Edit

IABSD.fr/xenocara/lib/mesa/src/intel/compiler/brw_fs_nir.cpp

Branch :

  • Show log

    Commit

  • Author : jsg
    Date : 2025-06-05 14:17:56
    Hash : 452696b8
    Message : Merge Mesa 25.0.7

  • lib/mesa/src/intel/compiler/brw_fs_nir.cpp
  • /*
     * Copyright © 2010 Intel Corporation
     *
     * Permission is hereby granted, free of charge, to any person obtaining a
     * copy of this software and associated documentation files (the "Software"),
     * to deal in the Software without restriction, including without limitation
     * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     * and/or sell copies of the Software, and to permit persons to whom the
     * Software is furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice (including the next
     * paragraph) shall be included in all copies or substantial portions of the
     * Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     * IN THE SOFTWARE.
     */
    
    #include "brw_fs.h"
    #include "brw_builder.h"
    #include "brw_nir.h"
    #include "brw_eu.h"
    #include "nir.h"
    #include "nir_intrinsics.h"
    #include "nir_search_helpers.h"
    #include "dev/intel_debug.h"
    #include "util/u_math.h"
    #include "util/bitscan.h"
    
    #include <vector>
    
    using namespace brw;
    
    struct brw_fs_bind_info {
       bool valid;
       bool bindless;
       unsigned block;
       unsigned set;
       unsigned binding;
    };
    
    struct nir_to_brw_state {
       fs_visitor &s;
       const nir_shader *nir;
       const intel_device_info *devinfo;
       void *mem_ctx;
    
       /* Points to the end of the program.  Annotated with the current NIR
        * instruction when applicable.
        */
       brw_builder bld;
    
       brw_reg *ssa_values;
       struct brw_fs_bind_info *ssa_bind_infos;
       brw_reg *system_values;
    
       bool annotate;
    };
    
    static brw_reg get_nir_src(nir_to_brw_state &ntb, const nir_src &src, int channel = 0);
    static brw_reg get_nir_def(nir_to_brw_state &ntb, const nir_def &def, bool all_sources_uniform = false);
    static nir_component_mask_t get_nir_write_mask(const nir_def &def);
    
    static void fs_nir_emit_intrinsic(nir_to_brw_state &ntb, const brw_builder &bld, nir_intrinsic_instr *instr);
    static brw_reg emit_samplepos_setup(nir_to_brw_state &ntb);
    static brw_reg emit_sampleid_setup(nir_to_brw_state &ntb);
    static brw_reg emit_samplemaskin_setup(nir_to_brw_state &ntb);
    static brw_reg emit_shading_rate_setup(nir_to_brw_state &ntb);
    
    static void fs_nir_emit_impl(nir_to_brw_state &ntb, nir_function_impl *impl);
    static void fs_nir_emit_cf_list(nir_to_brw_state &ntb, exec_list *list);
    static void fs_nir_emit_if(nir_to_brw_state &ntb, nir_if *if_stmt);
    static void fs_nir_emit_loop(nir_to_brw_state &ntb, nir_loop *loop);
    static void fs_nir_emit_block(nir_to_brw_state &ntb, nir_block *block);
    static void fs_nir_emit_instr(nir_to_brw_state &ntb, nir_instr *instr);
    
    static void fs_nir_emit_memory_access(nir_to_brw_state &ntb,
                                          const brw_builder &bld,
                                          const brw_builder &xbld,
                                          nir_intrinsic_instr *instr);
    
    static void brw_combine_with_vec(const brw_builder &bld, const brw_reg &dst,
                                     const brw_reg &src, unsigned n);
    
    static bool
    brw_texture_offset(const nir_tex_instr *tex, unsigned src,
                       uint32_t *offset_bits_out)
    {
       if (!nir_src_is_const(tex->src[src].src))
          return false;
    
       const unsigned num_components = nir_tex_instr_src_size(tex, src);
    
       /* Combine all three offsets into a single unsigned dword:
        *
        *    bits 11:8 - U Offset (X component)
        *    bits  7:4 - V Offset (Y component)
        *    bits  3:0 - R Offset (Z component)
        */
       uint32_t offset_bits = 0;
       for (unsigned i = 0; i < num_components; i++) {
          int offset = nir_src_comp_as_int(tex->src[src].src, i);
    
          /* offset out of bounds; caller will handle it. */
          if (offset > 7 || offset < -8)
             return false;
    
          const unsigned shift = 4 * (2 - i);
          offset_bits |= (offset & 0xF) << shift;
       }
    
       *offset_bits_out = offset_bits;
    
       return true;
    }
    
    static brw_reg
    setup_imm_b(const brw_builder &bld, int8_t v)
    {
       const brw_reg tmp = bld.vgrf(BRW_TYPE_B);
       bld.MOV(tmp, brw_imm_w(v));
       return tmp;
    }
    
    static void
    fs_nir_setup_outputs(nir_to_brw_state &ntb)
    {
       fs_visitor &s = ntb.s;
    
       if (s.stage == MESA_SHADER_TESS_CTRL ||
           s.stage == MESA_SHADER_TASK ||
           s.stage == MESA_SHADER_MESH ||
           s.stage == MESA_SHADER_FRAGMENT ||
           s.stage == MESA_SHADER_COMPUTE)
          return;
    
       unsigned vec4s[VARYING_SLOT_TESS_MAX] = { 0, };
    
       /* Calculate the size of output registers in a separate pass, before
        * allocating them.  With ARB_enhanced_layouts, multiple output variables
        * may occupy the same slot, but have different type sizes.
        */
       nir_foreach_shader_out_variable(var, s.nir) {
          const int loc = var->data.driver_location;
          const unsigned var_vec4s = nir_variable_count_slots(var, var->type);
          vec4s[loc] = MAX2(vec4s[loc], var_vec4s);
       }
    
       for (unsigned loc = 0; loc < ARRAY_SIZE(vec4s);) {
          if (vec4s[loc] == 0) {
             loc++;
             continue;
          }
    
          unsigned reg_size = vec4s[loc];
    
          /* Check if there are any ranges that start within this range and extend
           * past it. If so, include them in this allocation.
           */
          for (unsigned i = 1; i < reg_size; i++) {
             assert(i + loc < ARRAY_SIZE(vec4s));
             reg_size = MAX2(vec4s[i + loc] + i, reg_size);
          }
    
          brw_reg reg = ntb.bld.vgrf(BRW_TYPE_F, 4 * reg_size);
          for (unsigned i = 0; i < reg_size; i++) {
             assert(loc + i < ARRAY_SIZE(s.outputs));
             s.outputs[loc + i] = offset(reg, ntb.bld, 4 * i);
          }
    
          loc += reg_size;
       }
    }
    
    static void
    fs_nir_setup_uniforms(fs_visitor &s)
    {
       const intel_device_info *devinfo = s.devinfo;
    
       /* Only the first compile gets to set up uniforms. */
       if (s.uniforms)
          return;
    
       s.uniforms = s.nir->num_uniforms / 4;
    
       if (gl_shader_stage_is_compute(s.stage) && devinfo->verx10 < 125) {
          /* Add uniforms for builtins after regular NIR uniforms. */
          assert(s.uniforms == s.prog_data->nr_params);
    
          /* Subgroup ID must be the last uniform on the list.  This will make
           * easier later to split between cross thread and per thread
           * uniforms.
           */
          uint32_t *param = brw_stage_prog_data_add_params(s.prog_data, 1);
          *param = BRW_PARAM_BUILTIN_SUBGROUP_ID;
          s.uniforms++;
       }
    }
    
    static brw_reg
    emit_work_group_id_setup(nir_to_brw_state &ntb)
    {
       fs_visitor &s = ntb.s;
       const brw_builder &bld = ntb.bld.scalar_group();
    
       assert(gl_shader_stage_is_compute(s.stage));
    
       brw_reg id = bld.vgrf(BRW_TYPE_UD, 3);
    
       id.is_scalar = true;
    
       struct brw_reg r0_1(retype(brw_vec1_grf(0, 1), BRW_TYPE_UD));
       bld.MOV(id, r0_1);
    
       struct brw_reg r0_6(retype(brw_vec1_grf(0, 6), BRW_TYPE_UD));
       struct brw_reg r0_7(retype(brw_vec1_grf(0, 7), BRW_TYPE_UD));
       bld.MOV(offset(id, bld, 1), r0_6);
       bld.MOV(offset(id, bld, 2), r0_7);
    
       return id;
    }
    
    static bool
    emit_system_values_block(nir_to_brw_state &ntb, nir_block *block)
    {
       fs_visitor &s = ntb.s;
       brw_reg *reg;
    
       nir_foreach_instr(instr, block) {
          if (instr->type != nir_instr_type_intrinsic)
             continue;
    
          nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
          switch (intrin->intrinsic) {
          case nir_intrinsic_load_vertex_id:
          case nir_intrinsic_load_base_vertex:
             unreachable("should be lowered by nir_lower_system_values().");
    
          case nir_intrinsic_load_vertex_id_zero_base:
          case nir_intrinsic_load_is_indexed_draw:
          case nir_intrinsic_load_first_vertex:
          case nir_intrinsic_load_instance_id:
          case nir_intrinsic_load_base_instance:
             unreachable("should be lowered by brw_nir_lower_vs_inputs().");
             break;
    
          case nir_intrinsic_load_draw_id:
             /* For Task/Mesh, draw_id will be handled later in
              * nir_emit_mesh_task_intrinsic().
              */
             if (!gl_shader_stage_is_mesh(s.stage))
                unreachable("should be lowered by brw_nir_lower_vs_inputs().");
             break;
    
          case nir_intrinsic_load_invocation_id:
             if (s.stage == MESA_SHADER_TESS_CTRL)
                break;
             assert(s.stage == MESA_SHADER_GEOMETRY);
             reg = &ntb.system_values[SYSTEM_VALUE_INVOCATION_ID];
             if (reg->file == BAD_FILE) {
                *reg = s.gs_payload().instance_id;
             }
             break;
    
          case nir_intrinsic_load_sample_pos:
          case nir_intrinsic_load_sample_pos_or_center:
             assert(s.stage == MESA_SHADER_FRAGMENT);
             reg = &ntb.system_values[SYSTEM_VALUE_SAMPLE_POS];
             if (reg->file == BAD_FILE)
                *reg = emit_samplepos_setup(ntb);
             break;
    
          case nir_intrinsic_load_sample_id:
             assert(s.stage == MESA_SHADER_FRAGMENT);
             reg = &ntb.system_values[SYSTEM_VALUE_SAMPLE_ID];
             if (reg->file == BAD_FILE)
                *reg = emit_sampleid_setup(ntb);
             break;
    
          case nir_intrinsic_load_sample_mask_in:
             assert(s.stage == MESA_SHADER_FRAGMENT);
             reg = &ntb.system_values[SYSTEM_VALUE_SAMPLE_MASK_IN];
             if (reg->file == BAD_FILE)
                *reg = emit_samplemaskin_setup(ntb);
             break;
    
          case nir_intrinsic_load_workgroup_id:
             if (gl_shader_stage_is_mesh(s.stage))
                unreachable("should be lowered by nir_lower_compute_system_values().");
             assert(gl_shader_stage_is_compute(s.stage));
             reg = &ntb.system_values[SYSTEM_VALUE_WORKGROUP_ID];
             if (reg->file == BAD_FILE)
                *reg = emit_work_group_id_setup(ntb);
             break;
    
          case nir_intrinsic_load_helper_invocation:
             assert(s.stage == MESA_SHADER_FRAGMENT);
             reg = &ntb.system_values[SYSTEM_VALUE_HELPER_INVOCATION];
             if (reg->file == BAD_FILE) {
                const brw_builder abld =
                   ntb.bld.annotate("gl_HelperInvocation");
    
                /* On Gfx6+ (gl_HelperInvocation is only exposed on Gfx7+) the
                 * pixel mask is in g1.7 of the thread payload.
                 *
                 * We move the per-channel pixel enable bit to the low bit of each
                 * channel by shifting the byte containing the pixel mask by the
                 * vector immediate 0x76543210UV.
                 *
                 * The region of <1,8,0> reads only 1 byte (the pixel masks for
                 * subspans 0 and 1) in SIMD8 and an additional byte (the pixel
                 * masks for 2 and 3) in SIMD16.
                 */
                brw_reg shifted = abld.vgrf(BRW_TYPE_UW);
    
                for (unsigned i = 0; i < DIV_ROUND_UP(s.dispatch_width, 16); i++) {
                   const brw_builder hbld = abld.group(MIN2(16, s.dispatch_width), i);
                   /* According to the "PS Thread Payload for Normal
                    * Dispatch" pages on the BSpec, the dispatch mask is
                    * stored in R0.15/R1.15 on gfx20+ and in R1.7/R2.7 on
                    * gfx6+.
                    */
                   const struct brw_reg reg = s.devinfo->ver >= 20 ?
                      xe2_vec1_grf(i, 15) : brw_vec1_grf(i + 1, 7);
                   hbld.SHR(offset(shifted, hbld, i),
                            stride(retype(reg, BRW_TYPE_UB), 1, 8, 0),
                            brw_imm_v(0x76543210));
                }
    
                /* A set bit in the pixel mask means the channel is enabled, but
                 * that is the opposite of gl_HelperInvocation so we need to invert
                 * the mask.
                 *
                 * The negate source-modifier bit of logical instructions on Gfx8+
                 * performs 1's complement negation, so we can use that instead of
                 * a NOT instruction.
                 */
                brw_reg inverted = negate(shifted);
    
                /* We then resolve the 0/1 result to 0/~0 boolean values by ANDing
                 * with 1 and negating.
                 */
                brw_reg anded = abld.vgrf(BRW_TYPE_UD);
                abld.AND(anded, inverted, brw_imm_uw(1));
    
                *reg = abld.MOV(negate(retype(anded, BRW_TYPE_D)));
             }
             break;
    
          case nir_intrinsic_load_frag_shading_rate:
             reg = &ntb.system_values[SYSTEM_VALUE_FRAG_SHADING_RATE];
             if (reg->file == BAD_FILE)
                *reg = emit_shading_rate_setup(ntb);
             break;
    
          default:
             break;
          }
       }
    
       return true;
    }
    
    static void
    fs_nir_emit_system_values(nir_to_brw_state &ntb)
    {
       fs_visitor &s = ntb.s;
    
       ntb.system_values = ralloc_array(ntb.mem_ctx, brw_reg, SYSTEM_VALUE_MAX);
       for (unsigned i = 0; i < SYSTEM_VALUE_MAX; i++) {
          ntb.system_values[i] = brw_reg();
       }
    
       nir_function_impl *impl = nir_shader_get_entrypoint((nir_shader *)s.nir);
       nir_foreach_block(block, impl)
          emit_system_values_block(ntb, block);
    }
    
    static void
    fs_nir_emit_impl(nir_to_brw_state &ntb, nir_function_impl *impl)
    {
       ntb.ssa_values = rzalloc_array(ntb.mem_ctx, brw_reg, impl->ssa_alloc);
       ntb.ssa_bind_infos = rzalloc_array(ntb.mem_ctx, struct brw_fs_bind_info, impl->ssa_alloc);
    
       fs_nir_emit_cf_list(ntb, &impl->body);
    }
    
    static void
    fs_nir_emit_cf_list(nir_to_brw_state &ntb, exec_list *list)
    {
       exec_list_validate(list);
       foreach_list_typed(nir_cf_node, node, node, list) {
          switch (node->type) {
          case nir_cf_node_if:
             fs_nir_emit_if(ntb, nir_cf_node_as_if(node));
             break;
    
          case nir_cf_node_loop:
             fs_nir_emit_loop(ntb, nir_cf_node_as_loop(node));
             break;
    
          case nir_cf_node_block:
             fs_nir_emit_block(ntb, nir_cf_node_as_block(node));
             break;
    
          default:
             unreachable("Invalid CFG node block");
          }
       }
    }
    
    static void
    fs_nir_emit_if(nir_to_brw_state &ntb, nir_if *if_stmt)
    {
       const brw_builder &bld = ntb.bld;
    
       bool invert;
       brw_reg cond_reg;
    
       /* If the condition has the form !other_condition, use other_condition as
        * the source, but invert the predicate on the if instruction.
        */
       nir_alu_instr *cond = nir_src_as_alu_instr(if_stmt->condition);
       if (cond != NULL && cond->op == nir_op_inot) {
          invert = true;
          cond_reg = get_nir_src(ntb, cond->src[0].src, cond->src[0].swizzle[0]);
       } else {
          invert = false;
          cond_reg = get_nir_src(ntb, if_stmt->condition);
       }
    
       /* first, put the condition into f0 */
       fs_inst *inst = bld.MOV(bld.null_reg_d(),
                               retype(cond_reg, BRW_TYPE_D));
       inst->conditional_mod = BRW_CONDITIONAL_NZ;
    
       fs_inst *iff = bld.IF(BRW_PREDICATE_NORMAL);
       iff->predicate_inverse = invert;
    
       fs_nir_emit_cf_list(ntb, &if_stmt->then_list);
    
       if (!nir_cf_list_is_empty_block(&if_stmt->else_list)) {
          bld.emit(BRW_OPCODE_ELSE);
          fs_nir_emit_cf_list(ntb, &if_stmt->else_list);
       }
    
       fs_inst *endif = bld.emit(BRW_OPCODE_ENDIF);
    
       /* Peephole: replace IF-JUMP-ENDIF with predicated jump */
       if (endif->prev->prev == iff) {
          fs_inst *jump = (fs_inst *) endif->prev;
          if (jump->predicate == BRW_PREDICATE_NONE &&
              (jump->opcode == BRW_OPCODE_BREAK ||
               jump->opcode == BRW_OPCODE_CONTINUE)) {
             jump->predicate = iff->predicate;
             jump->predicate_inverse = iff->predicate_inverse;
             iff->exec_node::remove();
             endif->exec_node::remove();
          }
       }
    }
    
    static void
    fs_nir_emit_loop(nir_to_brw_state &ntb, nir_loop *loop)
    {
       const brw_builder &bld = ntb.bld;
    
       assert(!nir_loop_has_continue_construct(loop));
       bld.emit(BRW_OPCODE_DO);
    
       fs_nir_emit_cf_list(ntb, &loop->body);
    
       fs_inst *peep_while = bld.emit(BRW_OPCODE_WHILE);
    
       /* Peephole: replace (+f0) break; while with (-f0) while */
       fs_inst *peep_break = (fs_inst *) peep_while->prev;
    
       if (peep_break->opcode == BRW_OPCODE_BREAK &&
           peep_break->predicate != BRW_PREDICATE_NONE) {
          peep_while->predicate = peep_break->predicate;
          peep_while->predicate_inverse = !peep_break->predicate_inverse;
          peep_break->exec_node::remove();
       }
    }
    
    static void
    fs_nir_emit_block(nir_to_brw_state &ntb, nir_block *block)
    {
       brw_builder bld = ntb.bld;
    
       nir_foreach_instr(instr, block) {
          fs_nir_emit_instr(ntb, instr);
       }
    
       ntb.bld = bld;
    }
    
    /**
     * Recognizes a parent instruction of nir_op_extract_* and changes the type to
     * match instr.
     */
    static bool
    optimize_extract_to_float(nir_to_brw_state &ntb, const brw_builder &bld,
                              nir_alu_instr *instr, const brw_reg &result)
    {
       const intel_device_info *devinfo = ntb.devinfo;
    
       /* No fast path for f16 (yet) or f64. */
       assert(instr->op == nir_op_i2f32 || instr->op == nir_op_u2f32);
    
       if (!instr->src[0].src.ssa->parent_instr)
          return false;
    
       if (instr->src[0].src.ssa->parent_instr->type != nir_instr_type_alu)
          return false;
    
       nir_alu_instr *src0 =
          nir_instr_as_alu(instr->src[0].src.ssa->parent_instr);
    
       unsigned bytes;
       bool is_signed;
    
       switch (src0->op) {
       case nir_op_extract_u8:
       case nir_op_extract_u16:
          bytes = src0->op == nir_op_extract_u8 ? 1 : 2;
    
          /* i2f(extract_u8(a, b)) and u2f(extract_u8(a, b)) produce the same
           * result. Ditto for extract_u16.
           */
          is_signed = false;
          break;
    
       case nir_op_extract_i8:
       case nir_op_extract_i16:
          bytes = src0->op == nir_op_extract_i8 ? 1 : 2;
    
          /* The fast path can't handle u2f(extract_i8(a, b)) because the implicit
           * sign extension of the extract_i8 is lost. For example,
           * u2f(extract_i8(0x0000ff00, 1)) should produce 4294967295.0, but a
           * fast path could either give 255.0 (by implementing the fast path as
           * u2f(extract_u8(x))) or -1.0 (by implementing the fast path as
           * i2f(extract_i8(x))). At one point in time, we incorrectly implemented
           * the former.
           */
          if (instr->op != nir_op_i2f32)
             return false;
    
          is_signed = true;
          break;
    
       default:
          return false;
       }
    
       unsigned element = nir_src_as_uint(src0->src[1].src);
    
       /* Element type to extract.*/
       const brw_reg_type type = brw_int_type(bytes, is_signed);
    
       brw_reg op0 = get_nir_src(ntb, src0->src[0].src, -1);
       op0.type = brw_type_for_nir_type(devinfo,
          (nir_alu_type)(nir_op_infos[src0->op].input_types[0] |
                         nir_src_bit_size(src0->src[0].src)));
    
       /* It is not documented in the Bspec, but DG2 and newer platforms cannot do
        * direct byte-to-float conversions from scalars. MR !30140 has more
        * details. If the optimization is applied in cases that would require
        * lower_regioning to do some lowering, the code generated will be much,
        * much worse.
        */
       if (devinfo->verx10 >= 125 && bytes == 1) {
          /* If the source truly scalar, for example from the UNIFORM file, skip
           * the optimize_extract_to_float optimization.
           *
           * Note: is_scalar values won't have zero stride until after the call to
           * offset() below that applies the swizzle.
           */
          if (is_uniform(op0))
             return false;
    
          /* If the dispatch width matches the scalar allocation width, then
           * is_scalar can be demoted to non-is_scalar. This prevents offset() and
           * component() (both called below) from setting the stride to zero, and
           * that avoids the awful code generated by lower_regioning.
           */
          if (op0.is_scalar) {
             const unsigned allocation_width = 8 * reg_unit(ntb.devinfo);
             if (ntb.bld.dispatch_width() != allocation_width)
                return false;
    
             assert(bld.dispatch_width() == allocation_width);
             op0.is_scalar = false;
          }
       }
    
       op0 = offset(op0, bld, src0->src[0].swizzle[0]);
    
       /* If the dispatch width matches the scalar allocation width, offset() will
        * not modify the stride, but having source stride <0;1,0> is advantageous.
        */
       if (op0.is_scalar)
          op0 = component(op0, 0);
    
       /* Bspec "Register Region Restrictions" for Xe says:
        *
        *    "In case of all float point data types used in destination
        *
        *    1. Register Regioning patterns where register data bit location of
        *       the LSB of the channels are changed between source and destination
        *       are not supported on Src0 and Src1 except for broadcast of a
        *       scalar."
        *
        * This restriction is enfored in brw_lower_regioning.  There is no
        * reason to generate an optimized instruction that brw_lower_regioning
        * will have to break up later.
        */
       if (devinfo->verx10 >= 125 && element != 0 && !is_uniform(op0))
          return false;
    
       bld.MOV(result, subscript(op0, type, element));
       return true;
    }
    
    static bool
    optimize_frontfacing_ternary(nir_to_brw_state &ntb,
                                 nir_alu_instr *instr,
                                 const brw_reg &result)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       fs_visitor &s = ntb.s;
    
       nir_intrinsic_instr *src0 = nir_src_as_intrinsic(instr->src[0].src);
       if (src0 == NULL || src0->intrinsic != nir_intrinsic_load_front_face)
          return false;
    
       if (!nir_src_is_const(instr->src[1].src) ||
           !nir_src_is_const(instr->src[2].src))
          return false;
    
       const float value1 = nir_src_as_float(instr->src[1].src);
       const float value2 = nir_src_as_float(instr->src[2].src);
       if (fabsf(value1) != 1.0f || fabsf(value2) != 1.0f)
          return false;
    
       /* nir_opt_algebraic should have gotten rid of bcsel(b, a, a) */
       assert(value1 == -value2);
    
       brw_reg tmp = ntb.bld.vgrf(BRW_TYPE_D);
    
       if (devinfo->ver >= 20) {
          /* Gfx20+ has separate back-facing bits for each pair of
           * subspans in order to support multiple polygons, so we need to
           * use a <1;8,0> region in order to select the correct word for
           * each channel.  Unfortunately they're no longer aligned to the
           * sign bit of a 16-bit word, so a left shift is necessary.
           */
          brw_reg ff = ntb.bld.vgrf(BRW_TYPE_UW);
    
          for (unsigned i = 0; i < DIV_ROUND_UP(s.dispatch_width, 16); i++) {
             const brw_builder hbld = ntb.bld.group(16, i);
             const struct brw_reg gi_uw = retype(xe2_vec1_grf(i, 9),
                                                 BRW_TYPE_UW);
             hbld.SHL(offset(ff, hbld, i), stride(gi_uw, 1, 8, 0), brw_imm_ud(4));
          }
    
          if (value1 == -1.0f)
             ff.negate = true;
    
          ntb.bld.OR(subscript(tmp, BRW_TYPE_UW, 1), ff,
                      brw_imm_uw(0x3f80));
    
       } else if (devinfo->ver >= 12 && s.max_polygons == 2) {
          /* According to the BSpec "PS Thread Payload for Normal
           * Dispatch", the front/back facing interpolation bit is stored
           * as bit 15 of either the R1.1 or R1.6 poly info field, for the
           * first and second polygons respectively in multipolygon PS
           * dispatch mode.
           */
          assert(s.dispatch_width == 16);
    
          for (unsigned i = 0; i < s.max_polygons; i++) {
             const brw_builder hbld = ntb.bld.group(8, i);
             struct brw_reg g1 = retype(brw_vec1_grf(1, 1 + 5 * i),
                                        BRW_TYPE_UW);
    
             if (value1 == -1.0f)
                g1.negate = true;
    
             hbld.OR(subscript(offset(tmp, hbld, i), BRW_TYPE_UW, 1),
                     g1, brw_imm_uw(0x3f80));
          }
    
       } else if (devinfo->ver >= 12) {
          /* Bit 15 of g1.1 is 0 if the polygon is front facing. */
          brw_reg g1 = brw_reg(retype(brw_vec1_grf(1, 1), BRW_TYPE_W));
    
          /* For (gl_FrontFacing ? 1.0 : -1.0), emit:
           *
           *    or(8)  tmp.1<2>W  g1.1<0,1,0>W  0x00003f80W
           *    and(8) dst<1>D    tmp<8,8,1>D   0xbf800000D
           *
           * and negate g1.1<0,1,0>W for (gl_FrontFacing ? -1.0 : 1.0).
           */
          if (value1 == -1.0f)
             g1.negate = true;
    
          ntb.bld.OR(subscript(tmp, BRW_TYPE_W, 1),
                      g1, brw_imm_uw(0x3f80));
       } else {
          /* Bit 15 of g0.0 is 0 if the polygon is front facing. */
          brw_reg g0 = brw_reg(retype(brw_vec1_grf(0, 0), BRW_TYPE_W));
    
          /* For (gl_FrontFacing ? 1.0 : -1.0), emit:
           *
           *    or(8)  tmp.1<2>W  g0.0<0,1,0>W  0x00003f80W
           *    and(8) dst<1>D    tmp<8,8,1>D   0xbf800000D
           *
           * and negate g0.0<0,1,0>W for (gl_FrontFacing ? -1.0 : 1.0).
           *
           * This negation looks like it's safe in practice, because bits 0:4 will
           * surely be TRIANGLES
           */
    
          if (value1 == -1.0f) {
             g0.negate = true;
          }
    
          ntb.bld.OR(subscript(tmp, BRW_TYPE_W, 1),
                      g0, brw_imm_uw(0x3f80));
       }
       ntb.bld.AND(retype(result, BRW_TYPE_D), tmp, brw_imm_d(0xbf800000));
    
       return true;
    }
    
    static brw_rnd_mode
    brw_rnd_mode_from_nir_op (const nir_op op) {
       switch (op) {
       case nir_op_f2f16_rtz:
          return BRW_RND_MODE_RTZ;
       case nir_op_f2f16_rtne:
          return BRW_RND_MODE_RTNE;
       default:
          unreachable("Operation doesn't support rounding mode");
       }
    }
    
    static brw_rnd_mode
    brw_rnd_mode_from_execution_mode(unsigned execution_mode)
    {
       if (nir_has_any_rounding_mode_rtne(execution_mode))
          return BRW_RND_MODE_RTNE;
       if (nir_has_any_rounding_mode_rtz(execution_mode))
          return BRW_RND_MODE_RTZ;
       return BRW_RND_MODE_UNSPECIFIED;
    }
    
    static brw_reg
    prepare_alu_destination_and_sources(nir_to_brw_state &ntb,
                                        const brw_builder &bld,
                                        nir_alu_instr *instr,
                                        brw_reg *op,
                                        bool need_dest)
    {
       const intel_device_info *devinfo = ntb.devinfo;
    
       bool all_sources_uniform = true;
       for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
          op[i] = get_nir_src(ntb, instr->src[i].src, -1);
          op[i].type = brw_type_for_nir_type(devinfo,
             (nir_alu_type)(nir_op_infos[instr->op].input_types[i] |
                            nir_src_bit_size(instr->src[i].src)));
    
          /* is_scalar sources won't be is_uniform because get_nir_src was passed
           * -1 as the channel.
           */
          if (!is_uniform(op[i]) && !op[i].is_scalar)
             all_sources_uniform = false;
       }
    
       brw_reg result =
          need_dest ? get_nir_def(ntb, instr->def, all_sources_uniform) : bld.null_reg_ud();
    
       result.type = brw_type_for_nir_type(devinfo,
          (nir_alu_type)(nir_op_infos[instr->op].output_type |
                         instr->def.bit_size));
    
       /* Move and vecN instrutions may still be vectored.  Return the raw,
        * vectored source and destination so that fs_visitor::nir_emit_alu can
        * handle it.  Other callers should not have to handle these kinds of
        * instructions.
        */
       switch (instr->op) {
       case nir_op_mov:
       case nir_op_vec2:
       case nir_op_vec3:
       case nir_op_vec4:
       case nir_op_vec8:
       case nir_op_vec16:
          return result;
       default:
          break;
       }
    
       const bool is_scalar = result.is_scalar || (!need_dest && all_sources_uniform);
       const brw_builder xbld = is_scalar ? bld.scalar_group() : bld;
    
       /* At this point, we have dealt with any instruction that operates on
        * more than a single channel.  Therefore, we can just adjust the source
        * and destination registers for that channel and emit the instruction.
        */
       unsigned channel = 0;
       if (nir_op_infos[instr->op].output_size == 0) {
          /* Since NIR is doing the scalarizing for us, we should only ever see
           * vectorized operations with a single channel.
           */
          nir_component_mask_t write_mask = get_nir_write_mask(instr->def);
          assert(util_bitcount(write_mask) == 1);
          channel = ffs(write_mask) - 1;
    
          result = offset(result, xbld, channel);
       }
    
       for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
          assert(nir_op_infos[instr->op].input_sizes[i] < 2);
          op[i] = offset(op[i], xbld, instr->src[i].swizzle[channel]);
    
          /* If the dispatch width matches the scalar allocation width, offset()
           * won't set the stride to zero. Force that here.
           */
          if (op[i].is_scalar)
             op[i] = component(op[i], 0);
       }
    
       return result;
    }
    
    static brw_reg
    resolve_source_modifiers(const brw_builder &bld, const brw_reg &src)
    {
       return (src.abs || src.negate) ? bld.MOV(src) : src;
    }
    
    static void
    resolve_inot_sources(nir_to_brw_state &ntb, const brw_builder &bld, nir_alu_instr *instr,
                         brw_reg *op)
    {
       for (unsigned i = 0; i < 2; i++) {
          nir_alu_instr *inot_instr = nir_src_as_alu_instr(instr->src[i].src);
    
          if (inot_instr != NULL && inot_instr->op == nir_op_inot) {
             /* The source of the inot is now the source of instr. */
             prepare_alu_destination_and_sources(ntb, bld, inot_instr, &op[i], false);
    
             assert(!op[i].negate);
             op[i].negate = true;
          } else {
             op[i] = resolve_source_modifiers(bld, op[i]);
          }
       }
    }
    
    static bool
    try_emit_b2fi_of_inot(nir_to_brw_state &ntb, const brw_builder &bld,
                          brw_reg result,
                          nir_alu_instr *instr)
    {
       const intel_device_info *devinfo = bld.shader->devinfo;
    
       if (devinfo->verx10 >= 125)
          return false;
    
       nir_alu_instr *inot_instr = nir_src_as_alu_instr(instr->src[0].src);
    
       if (inot_instr == NULL || inot_instr->op != nir_op_inot)
          return false;
    
       /* HF is also possible as a destination on BDW+.  For nir_op_b2i, the set
        * of valid size-changing combinations is a bit more complex.
        *
        * The source restriction is just because I was lazy about generating the
        * constant below.
        */
       if (instr->def.bit_size != 32 ||
           nir_src_bit_size(inot_instr->src[0].src) != 32)
          return false;
    
       /* b2[fi](inot(a)) maps a=0 => 1, a=-1 => 0.  Since a can only be 0 or -1,
        * this is float(1 + a).
        */
       brw_reg op;
    
       prepare_alu_destination_and_sources(ntb, bld, inot_instr, &op, false);
    
       /* Ignore the saturate modifier, if there is one.  The result of the
        * arithmetic can only be 0 or 1, so the clamping will do nothing anyway.
        */
       bld.ADD(result, op, brw_imm_d(1));
    
       return true;
    }
    
    static bool
    is_const_zero(const nir_src &src)
    {
       return nir_src_is_const(src) && nir_src_as_int(src) == 0;
    }
    
    static void
    fs_nir_emit_alu(nir_to_brw_state &ntb, nir_alu_instr *instr,
                    bool need_dest)
    {
       const intel_device_info *devinfo = ntb.devinfo;
    
       fs_inst *inst;
       unsigned execution_mode =
          ntb.bld.shader->nir->info.float_controls_execution_mode;
    
       brw_reg op[NIR_MAX_VEC_COMPONENTS];
       brw_reg result = prepare_alu_destination_and_sources(ntb, ntb.bld, instr, op, need_dest);
    
    #ifndef NDEBUG
       /* Everything except raw moves, some type conversions, iabs, and ineg
        * should have 8-bit sources lowered by nir_lower_bit_size in
        * brw_preprocess_nir or by brw_nir_lower_conversions in
        * brw_postprocess_nir.
        */
       switch (instr->op) {
       case nir_op_mov:
       case nir_op_vec2:
       case nir_op_vec3:
       case nir_op_vec4:
       case nir_op_vec8:
       case nir_op_vec16:
       case nir_op_i2f16:
       case nir_op_i2f32:
       case nir_op_i2i16:
       case nir_op_i2i32:
       case nir_op_u2f16:
       case nir_op_u2f32:
       case nir_op_u2u16:
       case nir_op_u2u32:
       case nir_op_iabs:
       case nir_op_ineg:
       case nir_op_pack_32_4x8_split:
          break;
    
       default:
          for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
             assert(brw_type_size_bytes(op[i].type) > 1);
          }
       }
    #endif
    
       const brw_builder &bld = result.is_scalar ? ntb.bld.scalar_group() : ntb.bld;
    
       switch (instr->op) {
       case nir_op_mov:
       case nir_op_vec2:
       case nir_op_vec3:
       case nir_op_vec4:
       case nir_op_vec8:
       case nir_op_vec16: {
          brw_reg temp = result;
          bool need_extra_copy = false;
    
          nir_intrinsic_instr *store_reg =
             nir_store_reg_for_def(&instr->def);
          if (store_reg != NULL) {
             nir_def *dest_reg = store_reg->src[1].ssa;
             for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
                nir_intrinsic_instr *load_reg =
                   nir_load_reg_for_def(instr->src[i].src.ssa);
                if (load_reg == NULL)
                   continue;
    
                if (load_reg->src[0].ssa == dest_reg) {
                   need_extra_copy = true;
                   temp = bld.vgrf(result.type, 4);
                   break;
                }
             }
          }
    
          nir_component_mask_t write_mask = get_nir_write_mask(instr->def);
          unsigned last_bit = util_last_bit(write_mask);
    
          assert(last_bit <= NIR_MAX_VEC_COMPONENTS);
          brw_reg comps[NIR_MAX_VEC_COMPONENTS];
    
          for (unsigned i = 0; i < last_bit; i++) {
             if (instr->op == nir_op_mov)
                comps[i] = offset(op[0], bld, instr->src[0].swizzle[i]);
             else
                comps[i] = offset(op[i], bld, instr->src[i].swizzle[0]);
          }
    
          if (write_mask == (1u << last_bit) - 1) {
             bld.VEC(temp, comps, last_bit);
          } else {
             for (unsigned i = 0; i < last_bit; i++) {
                if (write_mask & (1 << i))
                   bld.MOV(offset(temp, bld, i), comps[i]);
             }
          }
    
          /* In this case the source and destination registers were the same,
           * so we need to insert an extra set of moves in order to deal with
           * any swizzling.
           */
          if (need_extra_copy) {
             for (unsigned i = 0; i < last_bit; i++) {
                if (!(write_mask & (1 << i)))
                   continue;
    
                bld.MOV(offset(result, bld, i), offset(temp, bld, i));
             }
          }
          return;
       }
    
       case nir_op_i2f32:
       case nir_op_u2f32:
          if (optimize_extract_to_float(ntb, bld, instr, result))
             return;
          bld.MOV(result, op[0]);
          break;
    
       case nir_op_f2f16_rtne:
       case nir_op_f2f16_rtz:
       case nir_op_f2f16: {
          brw_rnd_mode rnd = BRW_RND_MODE_UNSPECIFIED;
    
          if (nir_op_f2f16 == instr->op)
             rnd = brw_rnd_mode_from_execution_mode(execution_mode);
          else
             rnd = brw_rnd_mode_from_nir_op(instr->op);
    
          if (BRW_RND_MODE_UNSPECIFIED != rnd)
             bld.exec_all().emit(SHADER_OPCODE_RND_MODE, bld.null_reg_ud(), brw_imm_d(rnd));
    
          assert(brw_type_size_bytes(op[0].type) < 8); /* brw_nir_lower_conversions */
          bld.MOV(result, op[0]);
          break;
       }
    
       case nir_op_b2i8:
       case nir_op_b2i16:
       case nir_op_b2i32:
       case nir_op_b2i64:
       case nir_op_b2f16:
       case nir_op_b2f32:
       case nir_op_b2f64:
          if (try_emit_b2fi_of_inot(ntb, bld, result, instr))
             break;
          op[0].type = BRW_TYPE_D;
          op[0].negate = !op[0].negate;
          FALLTHROUGH;
       case nir_op_i2f64:
       case nir_op_i2i64:
       case nir_op_u2f64:
       case nir_op_u2u64:
       case nir_op_f2f64:
       case nir_op_f2i64:
       case nir_op_f2u64:
       case nir_op_i2i32:
       case nir_op_u2u32:
       case nir_op_f2i32:
       case nir_op_f2u32:
       case nir_op_i2f16:
       case nir_op_u2f16:
       case nir_op_f2i16:
       case nir_op_f2u16:
       case nir_op_f2i8:
       case nir_op_f2u8:
          if (result.type == BRW_TYPE_B ||
              result.type == BRW_TYPE_UB ||
              result.type == BRW_TYPE_HF)
             assert(brw_type_size_bytes(op[0].type) < 8); /* brw_nir_lower_conversions */
    
          if (op[0].type == BRW_TYPE_B ||
              op[0].type == BRW_TYPE_UB ||
              op[0].type == BRW_TYPE_HF)
             assert(brw_type_size_bytes(result.type) < 8); /* brw_nir_lower_conversions */
    
          bld.MOV(result, op[0]);
          break;
    
       case nir_op_i2i8:
       case nir_op_u2u8:
          assert(brw_type_size_bytes(op[0].type) < 8); /* brw_nir_lower_conversions */
          FALLTHROUGH;
       case nir_op_i2i16:
       case nir_op_u2u16: {
          /* Emit better code for u2u8(extract_u8(a, b)) and similar patterns.
           * Emitting the instructions one by one results in two MOV instructions
           * that won't be propagated.  By handling both instructions here, a
           * single MOV is emitted.
           */
          nir_alu_instr *extract_instr = nir_src_as_alu_instr(instr->src[0].src);
          if (extract_instr != NULL) {
             if (extract_instr->op == nir_op_extract_u8 ||
                 extract_instr->op == nir_op_extract_i8) {
                prepare_alu_destination_and_sources(ntb, ntb.bld, extract_instr, op, false);
    
                const unsigned byte = nir_src_as_uint(extract_instr->src[1].src);
                const brw_reg_type type =
                   brw_int_type(1, extract_instr->op == nir_op_extract_i8);
    
                op[0] = subscript(op[0], type, byte);
             } else if (extract_instr->op == nir_op_extract_u16 ||
                        extract_instr->op == nir_op_extract_i16) {
                prepare_alu_destination_and_sources(ntb, ntb.bld, extract_instr, op, false);
    
                const unsigned word = nir_src_as_uint(extract_instr->src[1].src);
                const brw_reg_type type =
                   brw_int_type(2, extract_instr->op == nir_op_extract_i16);
    
                op[0] = subscript(op[0], type, word);
             }
          }
    
          bld.MOV(result, op[0]);
          break;
       }
    
       case nir_op_fsat:
          inst = bld.MOV(result, op[0]);
          inst->saturate = true;
          break;
    
       case nir_op_fneg:
       case nir_op_ineg:
          op[0].negate = true;
          bld.MOV(result, op[0]);
          break;
    
       case nir_op_fabs:
       case nir_op_iabs:
          op[0].negate = false;
          op[0].abs = true;
          bld.MOV(result, op[0]);
          break;
    
       case nir_op_f2f32:
          if (nir_has_any_rounding_mode_enabled(execution_mode)) {
             brw_rnd_mode rnd =
                brw_rnd_mode_from_execution_mode(execution_mode);
             bld.exec_all().emit(SHADER_OPCODE_RND_MODE, bld.null_reg_ud(),
                                 brw_imm_d(rnd));
          }
    
          if (op[0].type == BRW_TYPE_HF)
             assert(brw_type_size_bytes(result.type) < 8); /* brw_nir_lower_conversions */
    
          bld.MOV(result, op[0]);
          break;
    
       case nir_op_fsign:
          unreachable("Should have been lowered by brw_nir_lower_fsign.");
    
       case nir_op_frcp:
          bld.RCP(result, op[0]);
          break;
    
       case nir_op_fexp2:
          bld.EXP2(result, op[0]);
          break;
    
       case nir_op_flog2:
          bld.LOG2(result, op[0]);
          break;
    
       case nir_op_fsin:
          bld.SIN(result, op[0]);
          break;
    
       case nir_op_fcos:
          bld.COS(result, op[0]);
          break;
    
       case nir_op_fadd:
          if (nir_has_any_rounding_mode_enabled(execution_mode)) {
             brw_rnd_mode rnd =
                brw_rnd_mode_from_execution_mode(execution_mode);
             bld.exec_all().emit(SHADER_OPCODE_RND_MODE, bld.null_reg_ud(),
                                 brw_imm_d(rnd));
          }
          FALLTHROUGH;
       case nir_op_iadd:
          bld.ADD(result, op[0], op[1]);
          break;
    
       case nir_op_iadd3:
          assert(instr->def.bit_size < 64);
          bld.ADD3(result, op[0], op[1], op[2]);
          break;
    
       case nir_op_iadd_sat:
       case nir_op_uadd_sat:
          inst = bld.ADD(result, op[0], op[1]);
          inst->saturate = true;
          break;
    
       case nir_op_isub_sat:
          bld.emit(SHADER_OPCODE_ISUB_SAT, result, op[0], op[1]);
          break;
    
       case nir_op_usub_sat:
          bld.emit(SHADER_OPCODE_USUB_SAT, result, op[0], op[1]);
          break;
    
       case nir_op_irhadd:
       case nir_op_urhadd:
          assert(instr->def.bit_size < 64);
          bld.AVG(result, op[0], op[1]);
          break;
    
       case nir_op_ihadd:
       case nir_op_uhadd: {
          assert(instr->def.bit_size < 64);
    
          op[0] = resolve_source_modifiers(bld, op[0]);
          op[1] = resolve_source_modifiers(bld, op[1]);
    
          /* AVG(x, y) - ((x ^ y) & 1) */
          brw_reg one = retype(brw_imm_ud(1), result.type);
          bld.ADD(result, bld.AVG(op[0], op[1]),
                  negate(bld.AND(bld.XOR(op[0], op[1]), one)));
          break;
       }
    
       case nir_op_fmul:
          if (nir_has_any_rounding_mode_enabled(execution_mode)) {
             brw_rnd_mode rnd =
                brw_rnd_mode_from_execution_mode(execution_mode);
             bld.exec_all().emit(SHADER_OPCODE_RND_MODE, bld.null_reg_ud(),
                                 brw_imm_d(rnd));
          }
    
          bld.MUL(result, op[0], op[1]);
          break;
    
       case nir_op_imul_2x32_64:
       case nir_op_umul_2x32_64:
          bld.MUL(result, op[0], op[1]);
          break;
    
       case nir_op_imul_32x16:
       case nir_op_umul_32x16: {
          const bool ud = instr->op == nir_op_umul_32x16;
          const enum brw_reg_type word_type = ud ? BRW_TYPE_UW : BRW_TYPE_W;
          const enum brw_reg_type dword_type = ud ? BRW_TYPE_UD : BRW_TYPE_D;
    
          assert(instr->def.bit_size == 32);
    
          /* Before copy propagation there are no immediate values. */
          assert(op[0].file != IMM && op[1].file != IMM);
    
          op[1] = subscript(op[1], word_type, 0);
    
          bld.MUL(result, retype(op[0], dword_type), op[1]);
    
          break;
       }
    
       case nir_op_imul:
          assert(instr->def.bit_size < 64);
          bld.MUL(result, op[0], op[1]);
          break;
    
       case nir_op_imul_high:
       case nir_op_umul_high:
          assert(instr->def.bit_size < 64);
          if (instr->def.bit_size == 32) {
             bld.emit(SHADER_OPCODE_MULH, result, op[0], op[1]);
          } else {
             brw_reg tmp = bld.vgrf(brw_type_with_size(op[0].type, 32));
             bld.MUL(tmp, op[0], op[1]);
             bld.MOV(result, subscript(tmp, result.type, 1));
          }
          break;
    
       case nir_op_idiv:
       case nir_op_udiv:
          assert(instr->def.bit_size < 64);
          bld.INT_QUOTIENT(result, op[0], op[1]);
          break;
    
       case nir_op_uadd_carry:
          unreachable("Should have been lowered by carry_to_arith().");
    
       case nir_op_usub_borrow:
          unreachable("Should have been lowered by borrow_to_arith().");
    
       case nir_op_umod:
       case nir_op_irem:
          /* According to the sign table for INT DIV in the Ivy Bridge PRM, it
           * appears that our hardware just does the right thing for signed
           * remainder.
           */
          assert(instr->def.bit_size < 64);
          bld.INT_REMAINDER(result, op[0], op[1]);
          break;
    
       case nir_op_imod: {
          /* Get a regular C-style remainder.  If a % b == 0, set the predicate. */
          bld.INT_REMAINDER(result, op[0], op[1]);
    
          /* Math instructions don't support conditional mod */
          inst = bld.MOV(bld.null_reg_d(), result);
          inst->conditional_mod = BRW_CONDITIONAL_NZ;
    
          /* Now, we need to determine if signs of the sources are different.
           * When we XOR the sources, the top bit is 0 if they are the same and 1
           * if they are different.  We can then use a conditional modifier to
           * turn that into a predicate.  This leads us to an XOR.l instruction.
           *
           * Technically, according to the PRM, you're not allowed to use .l on a
           * XOR instruction.  However, empirical experiments and Curro's reading
           * of the simulator source both indicate that it's safe.
           */
          bld.XOR(op[0], op[1], &inst);
          inst->predicate = BRW_PREDICATE_NORMAL;
          inst->conditional_mod = BRW_CONDITIONAL_L;
    
          /* If the result of the initial remainder operation is non-zero and the
           * two sources have different signs, add in a copy of op[1] to get the
           * final integer modulus value.
           */
          inst = bld.ADD(result, result, op[1]);
          inst->predicate = BRW_PREDICATE_NORMAL;
          break;
       }
    
       case nir_op_flt32:
       case nir_op_fge32:
       case nir_op_feq32:
       case nir_op_fneu32: {
          brw_reg dest = result;
    
          const uint32_t bit_size =  nir_src_bit_size(instr->src[0].src);
          if (bit_size != 32) {
             dest = bld.vgrf(op[0].type);
             bld.UNDEF(dest);
          }
    
          bld.CMP(dest, op[0], op[1], brw_cmod_for_nir_comparison(instr->op));
    
          /* The destination will now be used as a source, so select component 0
           * if it's is_scalar (as is done in get_nir_src).
           */
          if (bit_size != 32 && result.is_scalar)
             dest = component(dest, 0);
    
          if (bit_size > 32) {
             bld.MOV(result, subscript(dest, BRW_TYPE_UD, 0));
          } else if(bit_size < 32) {
             /* When we convert the result to 32-bit we need to be careful and do
              * it as a signed conversion to get sign extension (for 32-bit true)
              */
             const brw_reg_type src_type =
                brw_type_with_size(BRW_TYPE_D, bit_size);
    
             bld.MOV(retype(result, BRW_TYPE_D), retype(dest, src_type));
          }
          break;
       }
    
       case nir_op_ilt32:
       case nir_op_ult32:
       case nir_op_ige32:
       case nir_op_uge32:
       case nir_op_ieq32:
       case nir_op_ine32: {
          brw_reg dest = result;
    
          const uint32_t bit_size = brw_type_size_bits(op[0].type);
          if (bit_size != 32) {
             dest = bld.vgrf(op[0].type);
             bld.UNDEF(dest);
          }
    
          bld.CMP(dest, op[0], op[1],
                  brw_cmod_for_nir_comparison(instr->op));
    
          /* The destination will now be used as a source, so select component 0
           * if it's is_scalar (as is done in get_nir_src).
           */
          if (bit_size != 32 && result.is_scalar)
             dest = component(dest, 0);
    
          if (bit_size > 32) {
             bld.MOV(result, subscript(dest, BRW_TYPE_UD, 0));
          } else if (bit_size < 32) {
             /* When we convert the result to 32-bit we need to be careful and do
              * it as a signed conversion to get sign extension (for 32-bit true)
              */
             const brw_reg_type src_type =
                brw_type_with_size(BRW_TYPE_D, bit_size);
    
             bld.MOV(retype(result, BRW_TYPE_D), retype(dest, src_type));
          }
          break;
       }
    
       case nir_op_inot: {
          nir_alu_instr *inot_src_instr = nir_src_as_alu_instr(instr->src[0].src);
    
          if (inot_src_instr != NULL &&
              (inot_src_instr->op == nir_op_ior ||
               inot_src_instr->op == nir_op_ixor ||
               inot_src_instr->op == nir_op_iand)) {
             /* The sources of the source logical instruction are now the
              * sources of the instruction that will be generated.
              */
             prepare_alu_destination_and_sources(ntb, ntb.bld, inot_src_instr, op, false);
             resolve_inot_sources(ntb, bld, inot_src_instr, op);
    
             /* Smash all of the sources and destination to be signed.  This
              * doesn't matter for the operation of the instruction, but cmod
              * propagation fails on unsigned sources with negation (due to
              * fs_inst::can_do_cmod returning false).
              */
             result.type =
                brw_type_for_nir_type(devinfo,
                                      (nir_alu_type)(nir_type_int |
                                                     instr->def.bit_size));
             op[0].type =
                brw_type_for_nir_type(devinfo,
                                      (nir_alu_type)(nir_type_int |
                                                     nir_src_bit_size(inot_src_instr->src[0].src)));
             op[1].type =
                brw_type_for_nir_type(devinfo,
                                      (nir_alu_type)(nir_type_int |
                                                     nir_src_bit_size(inot_src_instr->src[1].src)));
    
             /* For XOR, only invert one of the sources.  Arbitrarily choose
              * the first source.
              */
             op[0].negate = !op[0].negate;
             if (inot_src_instr->op != nir_op_ixor)
                op[1].negate = !op[1].negate;
    
             switch (inot_src_instr->op) {
             case nir_op_ior:
                bld.AND(result, op[0], op[1]);
                return;
    
             case nir_op_iand:
                bld.OR(result, op[0], op[1]);
                return;
    
             case nir_op_ixor:
                bld.XOR(result, op[0], op[1]);
                return;
    
             default:
                unreachable("impossible opcode");
             }
          }
          op[0] = resolve_source_modifiers(bld, op[0]);
          bld.NOT(result, op[0]);
          break;
       }
    
       case nir_op_ixor:
          resolve_inot_sources(ntb, bld, instr, op);
          bld.XOR(result, op[0], op[1]);
          break;
       case nir_op_ior:
          resolve_inot_sources(ntb, bld, instr, op);
          bld.OR(result, op[0], op[1]);
          break;
       case nir_op_iand:
          resolve_inot_sources(ntb, bld, instr, op);
          bld.AND(result, op[0], op[1]);
          break;
    
       case nir_op_fdot2:
       case nir_op_fdot3:
       case nir_op_fdot4:
       case nir_op_b32all_fequal2:
       case nir_op_b32all_iequal2:
       case nir_op_b32all_fequal3:
       case nir_op_b32all_iequal3:
       case nir_op_b32all_fequal4:
       case nir_op_b32all_iequal4:
       case nir_op_b32any_fnequal2:
       case nir_op_b32any_inequal2:
       case nir_op_b32any_fnequal3:
       case nir_op_b32any_inequal3:
       case nir_op_b32any_fnequal4:
       case nir_op_b32any_inequal4:
          unreachable("Lowered by nir_lower_alu_reductions");
    
       case nir_op_ldexp:
          unreachable("not reached: should be handled by ldexp_to_arith()");
    
       case nir_op_fsqrt:
          bld.SQRT(result, op[0]);
          break;
    
       case nir_op_frsq:
          bld.RSQ(result, op[0]);
          break;
    
       case nir_op_ftrunc:
          bld.RNDZ(result, op[0]);
          break;
    
       case nir_op_fceil:
          bld.MOV(result, negate(bld.RNDD(negate(op[0]))));
          break;
       case nir_op_ffloor:
          bld.RNDD(result, op[0]);
          break;
       case nir_op_ffract:
          bld.FRC(result, op[0]);
          break;
       case nir_op_fround_even:
          bld.RNDE(result, op[0]);
          break;
    
       case nir_op_fquantize2f16: {
          brw_reg tmp16 = bld.vgrf(BRW_TYPE_D);
          brw_reg tmp32 = bld.vgrf(BRW_TYPE_F);
    
          /* The destination stride must be at least as big as the source stride. */
          tmp16 = subscript(tmp16, BRW_TYPE_HF, 0);
    
          /* Check for denormal */
          brw_reg abs_src0 = op[0];
          abs_src0.abs = true;
          bld.CMP(bld.null_reg_f(), abs_src0, brw_imm_f(ldexpf(1.0, -14)),
                  BRW_CONDITIONAL_L);
          /* Get the appropriately signed zero */
          brw_reg zero = retype(bld.AND(retype(op[0], BRW_TYPE_UD),
                                       brw_imm_ud(0x80000000)), BRW_TYPE_F);
          /* Do the actual F32 -> F16 -> F32 conversion */
          bld.MOV(tmp16, op[0]);
          bld.MOV(tmp32, tmp16);
          /* Select that or zero based on normal status */
          inst = bld.SEL(result, zero, tmp32);
          inst->predicate = BRW_PREDICATE_NORMAL;
          break;
       }
    
       case nir_op_imin:
       case nir_op_umin:
       case nir_op_fmin:
          bld.emit_minmax(result, op[0], op[1], BRW_CONDITIONAL_L);
          break;
    
       case nir_op_imax:
       case nir_op_umax:
       case nir_op_fmax:
          bld.emit_minmax(result, op[0], op[1], BRW_CONDITIONAL_GE);
          break;
    
       case nir_op_pack_snorm_2x16:
       case nir_op_pack_snorm_4x8:
       case nir_op_pack_unorm_2x16:
       case nir_op_pack_unorm_4x8:
       case nir_op_unpack_snorm_2x16:
       case nir_op_unpack_snorm_4x8:
       case nir_op_unpack_unorm_2x16:
       case nir_op_unpack_unorm_4x8:
       case nir_op_unpack_half_2x16:
       case nir_op_pack_half_2x16:
          unreachable("not reached: should be handled by lower_packing_builtins");
    
       case nir_op_unpack_half_2x16_split_x:
          bld.MOV(result, subscript(op[0], BRW_TYPE_HF, 0));
          break;
    
       case nir_op_unpack_half_2x16_split_y:
          bld.MOV(result, subscript(op[0], BRW_TYPE_HF, 1));
          break;
    
       case nir_op_pack_64_2x32_split:
       case nir_op_pack_32_2x16_split:
          bld.emit(FS_OPCODE_PACK, result, op[0], op[1]);
          break;
    
       case nir_op_pack_32_4x8_split:
          bld.emit(FS_OPCODE_PACK, result, op, 4);
          break;
    
       case nir_op_unpack_64_2x32_split_x:
       case nir_op_unpack_64_2x32_split_y: {
          if (instr->op == nir_op_unpack_64_2x32_split_x)
             bld.MOV(result, subscript(op[0], BRW_TYPE_UD, 0));
          else
             bld.MOV(result, subscript(op[0], BRW_TYPE_UD, 1));
          break;
       }
    
       case nir_op_unpack_32_2x16_split_x:
       case nir_op_unpack_32_2x16_split_y: {
          if (instr->op == nir_op_unpack_32_2x16_split_x)
             bld.MOV(result, subscript(op[0], BRW_TYPE_UW, 0));
          else
             bld.MOV(result, subscript(op[0], BRW_TYPE_UW, 1));
          break;
       }
    
       case nir_op_fpow:
          bld.POW(result, op[0], op[1]);
          break;
    
       case nir_op_bitfield_reverse:
          assert(instr->def.bit_size == 32);
          assert(nir_src_bit_size(instr->src[0].src) == 32);
          bld.BFREV(result, op[0]);
          break;
    
       case nir_op_bit_count:
          assert(instr->def.bit_size == 32);
          assert(nir_src_bit_size(instr->src[0].src) < 64);
          bld.CBIT(result, op[0]);
          break;
    
       case nir_op_uclz:
          assert(instr->def.bit_size == 32);
          assert(nir_src_bit_size(instr->src[0].src) == 32);
          bld.LZD(retype(result, BRW_TYPE_UD), op[0]);
          break;
    
       case nir_op_ifind_msb: {
          assert(instr->def.bit_size == 32);
          assert(nir_src_bit_size(instr->src[0].src) == 32);
    
          brw_reg tmp = bld.FBH(retype(op[0], BRW_TYPE_D));
    
          /* FBH counts from the MSB side, while GLSL's findMSB() wants the count
           * from the LSB side. If FBH didn't return an error (0xFFFFFFFF), then
           * subtract the result from 31 to convert the MSB count into an LSB
           * count.
           */
          brw_reg count_from_lsb = bld.ADD(negate(tmp), brw_imm_w(31));
    
          /* The high word of the FBH result will be 0xffff or 0x0000. After
           * calculating 31 - fbh, we can obtain the correct result for
           * ifind_msb(0) by ORing the (sign extended) upper word of the
           * intermediate result.
           */
          bld.OR(result, count_from_lsb, subscript(tmp, BRW_TYPE_W, 1));
          break;
       }
    
       case nir_op_find_lsb:
          assert(instr->def.bit_size == 32);
          assert(nir_src_bit_size(instr->src[0].src) == 32);
          bld.FBL(result, op[0]);
          break;
    
       case nir_op_ubitfield_extract:
       case nir_op_ibitfield_extract:
          unreachable("should have been lowered");
       case nir_op_ubfe:
       case nir_op_ibfe:
          assert(instr->def.bit_size < 64);
          bld.BFE(result, op[2], op[1], op[0]);
          break;
       case nir_op_bfm:
          assert(instr->def.bit_size < 64);
          bld.BFI1(result, op[0], op[1]);
          break;
       case nir_op_bfi:
          assert(instr->def.bit_size < 64);
    
          /* bfi is ((...) | (~src0 & src2)). The second part is zero when src2 is
           * either 0 or src0. Replacing the 0 with another value can eliminate a
           * temporary register.
           */
          if (is_const_zero(instr->src[2].src))
             bld.BFI2(result, op[0], op[1], op[0]);
          else
             bld.BFI2(result, op[0], op[1], op[2]);
    
          break;
    
       case nir_op_bitfield_insert:
          unreachable("not reached: should have been lowered");
    
       /* With regards to implicit masking of the shift counts for 8- and 16-bit
        * types, the PRMs are **incorrect**. They falsely state that on Gen9+ only
        * the low bits of src1 matching the size of src0 (e.g., 4-bits for W or UW
        * src0) are used. The Bspec (backed by data from experimentation) state
        * that 0x3f is used for Q and UQ types, and 0x1f is used for **all** other
        * types.
        *
        * The match the behavior expected for the NIR opcodes, explicit masks for
        * 8- and 16-bit types must be added.
        */
       case nir_op_ishl:
          if (instr->def.bit_size < 32) {
             bld.SHL(result,
                     op[0],
                     bld.AND(op[1], brw_imm_ud(instr->def.bit_size - 1)));
          } else {
             bld.SHL(result, op[0], op[1]);
          }
    
          break;
       case nir_op_ishr:
          if (instr->def.bit_size < 32) {
             bld.ASR(result,
                     op[0],
                     bld.AND(op[1], brw_imm_ud(instr->def.bit_size - 1)));
          } else {
             bld.ASR(result, op[0], op[1]);
          }
    
          break;
       case nir_op_ushr:
          if (instr->def.bit_size < 32) {
             bld.SHR(result,
                     op[0],
                     bld.AND(op[1], brw_imm_ud(instr->def.bit_size - 1)));
          } else {
             bld.SHR(result, op[0], op[1]);
          }
    
          break;
    
       case nir_op_urol:
          bld.ROL(result, op[0], op[1]);
          break;
       case nir_op_uror:
          bld.ROR(result, op[0], op[1]);
          break;
    
       case nir_op_pack_half_2x16_split:
          bld.emit(FS_OPCODE_PACK_HALF_2x16_SPLIT, result, op[0], op[1]);
          break;
    
       case nir_op_sdot_4x8_iadd:
       case nir_op_sdot_4x8_iadd_sat:
          inst = bld.DP4A(retype(result, BRW_TYPE_D),
                          retype(op[2], BRW_TYPE_D),
                          retype(op[0], BRW_TYPE_D),
                          retype(op[1], BRW_TYPE_D));
    
          if (instr->op == nir_op_sdot_4x8_iadd_sat)
             inst->saturate = true;
          break;
    
       case nir_op_udot_4x8_uadd:
       case nir_op_udot_4x8_uadd_sat:
          inst = bld.DP4A(retype(result, BRW_TYPE_UD),
                          retype(op[2], BRW_TYPE_UD),
                          retype(op[0], BRW_TYPE_UD),
                          retype(op[1], BRW_TYPE_UD));
    
          if (instr->op == nir_op_udot_4x8_uadd_sat)
             inst->saturate = true;
          break;
    
       case nir_op_sudot_4x8_iadd:
       case nir_op_sudot_4x8_iadd_sat:
          inst = bld.DP4A(retype(result, BRW_TYPE_D),
                          retype(op[2], BRW_TYPE_D),
                          retype(op[0], BRW_TYPE_D),
                          retype(op[1], BRW_TYPE_UD));
    
          if (instr->op == nir_op_sudot_4x8_iadd_sat)
             inst->saturate = true;
          break;
    
       case nir_op_ffma:
          if (nir_has_any_rounding_mode_enabled(execution_mode)) {
             brw_rnd_mode rnd =
                brw_rnd_mode_from_execution_mode(execution_mode);
             bld.exec_all().emit(SHADER_OPCODE_RND_MODE, bld.null_reg_ud(),
                                 brw_imm_d(rnd));
          }
    
          bld.MAD(result, op[2], op[1], op[0]);
          break;
    
       case nir_op_flrp:
          if (nir_has_any_rounding_mode_enabled(execution_mode)) {
             brw_rnd_mode rnd =
                brw_rnd_mode_from_execution_mode(execution_mode);
             bld.exec_all().emit(SHADER_OPCODE_RND_MODE, bld.null_reg_ud(),
                                 brw_imm_d(rnd));
          }
    
          bld.LRP(result, op[0], op[1], op[2]);
          break;
    
       case nir_op_b32csel:
          if (optimize_frontfacing_ternary(ntb, instr, result))
             return;
    
          bld.CMP(bld.null_reg_d(), op[0], brw_imm_d(0), BRW_CONDITIONAL_NZ);
          inst = bld.SEL(result, op[1], op[2]);
          inst->predicate = BRW_PREDICATE_NORMAL;
          break;
    
       case nir_op_fcsel:
          bld.CSEL(result, op[1], op[2], op[0], BRW_CONDITIONAL_NZ);
          break;
    
       case nir_op_fcsel_gt:
          bld.CSEL(result, op[1], op[2], op[0], BRW_CONDITIONAL_G);
          break;
    
       case nir_op_fcsel_ge:
          bld.CSEL(result, op[1], op[2], op[0], BRW_CONDITIONAL_GE);
          break;
    
       case nir_op_extract_u8:
       case nir_op_extract_i8: {
          const brw_reg_type type = brw_int_type(1, instr->op == nir_op_extract_i8);
          unsigned byte = nir_src_as_uint(instr->src[1].src);
    
          /* The PRMs say:
           *
           *    BDW+
           *    There is no direct conversion from B/UB to Q/UQ or Q/UQ to B/UB.
           *    Use two instructions and a word or DWord intermediate integer type.
           */
          if (instr->def.bit_size == 64) {
             if (instr->op == nir_op_extract_i8) {
                /* If we need to sign extend, extract to a word first */
                brw_reg w_temp = bld.vgrf(BRW_TYPE_W);
                bld.MOV(w_temp, subscript(op[0], type, byte));
                bld.MOV(result, w_temp);
             } else if (byte & 1) {
                /* Extract the high byte from the word containing the desired byte
                 * offset.
                 */
                bld.SHR(result,
                        subscript(op[0], BRW_TYPE_UW, byte / 2),
                        brw_imm_uw(8));
             } else {
                /* Otherwise use an AND with 0xff and a word type */
                bld.AND(result,
                        subscript(op[0], BRW_TYPE_UW, byte / 2),
                        brw_imm_uw(0xff));
             }
          } else {
             bld.MOV(result, subscript(op[0], type, byte));
          }
          break;
       }
    
       case nir_op_extract_u16:
       case nir_op_extract_i16: {
          const brw_reg_type type = brw_int_type(2, instr->op == nir_op_extract_i16);
          unsigned word = nir_src_as_uint(instr->src[1].src);
          bld.MOV(result, subscript(op[0], type, word));
          break;
       }
    
       default:
          unreachable("unhandled instruction");
       }
    }
    
    static void
    fs_nir_emit_load_const(nir_to_brw_state &ntb,
                           nir_load_const_instr *instr)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld.scalar_group();
    
       const brw_reg_type reg_type =
          brw_type_with_size(BRW_TYPE_D, instr->def.bit_size);
       brw_reg reg = bld.vgrf(reg_type, instr->def.num_components);
    
       reg.is_scalar = true;
    
       brw_reg comps[NIR_MAX_VEC_COMPONENTS];
    
       switch (instr->def.bit_size) {
       case 8:
          for (unsigned i = 0; i < instr->def.num_components; i++)
             comps[i] = setup_imm_b(bld, instr->value[i].i8);
          break;
    
       case 16:
          for (unsigned i = 0; i < instr->def.num_components; i++)
             comps[i] = brw_imm_w(instr->value[i].i16);
          break;
    
       case 32:
          for (unsigned i = 0; i < instr->def.num_components; i++)
             comps[i] = brw_imm_d(instr->value[i].i32);
          break;
    
       case 64:
          if (!devinfo->has_64bit_int) {
             reg.type = BRW_TYPE_DF;
             for (unsigned i = 0; i < instr->def.num_components; i++)
                comps[i] = brw_imm_df(instr->value[i].f64);
          } else {
             for (unsigned i = 0; i < instr->def.num_components; i++)
                comps[i] = brw_imm_q(instr->value[i].i64);
          }
          break;
    
       default:
          unreachable("Invalid bit size");
       }
    
       bld.VEC(reg, comps, instr->def.num_components);
    
       ntb.ssa_values[instr->def.index] = reg;
    }
    
    static bool
    get_nir_src_bindless(nir_to_brw_state &ntb, const nir_src &src)
    {
       return ntb.ssa_bind_infos[src.ssa->index].bindless;
    }
    
    /**
     * Specifying -1 for channel indicates that no channel selection should be applied.
     */
    static brw_reg
    get_nir_src(nir_to_brw_state &ntb, const nir_src &src, int channel)
    {
       nir_intrinsic_instr *load_reg = nir_load_reg_for_def(src.ssa);
    
       brw_reg reg;
       if (!load_reg) {
          if (nir_src_is_undef(src)) {
             const brw_reg_type reg_type =
                brw_type_with_size(BRW_TYPE_D, src.ssa->bit_size);
             reg = ntb.bld.vgrf(reg_type, src.ssa->num_components);
          } else {
             reg = ntb.ssa_values[src.ssa->index];
          }
       } else {
          nir_intrinsic_instr *decl_reg = nir_reg_get_decl(load_reg->src[0].ssa);
          /* We don't handle indirects on locals */
          assert(nir_intrinsic_base(load_reg) == 0);
          assert(load_reg->intrinsic != nir_intrinsic_load_reg_indirect);
          reg = ntb.ssa_values[decl_reg->def.index];
       }
    
       /* To avoid floating-point denorm flushing problems, set the type by
        * default to an integer type - instructions that need floating point
        * semantics will set this to F if they need to
        */
       reg.type = brw_type_with_size(BRW_TYPE_D, nir_src_bit_size(src));
    
       if (channel >= 0) {
          reg = offset(reg, ntb.bld, channel);
    
          /* If the dispatch width matches the scalar allocation width, offset()
           * won't set the stride to zero. Force that here.
           */
          if (reg.is_scalar)
             reg = component(reg, 0);
       }
    
       return reg;
    }
    
    /**
     * Return an IMM for 32-bit constants; otherwise call get_nir_src() as normal.
     */
    static brw_reg
    get_nir_src_imm(nir_to_brw_state &ntb, const nir_src &src)
    {
       return nir_src_is_const(src) && nir_src_bit_size(src) == 32 ?
              brw_reg(brw_imm_d(nir_src_as_int(src))) : get_nir_src(ntb, src);
    }
    
    static brw_reg
    get_nir_def(nir_to_brw_state &ntb, const nir_def &def, bool all_sources_uniform)
    {
       nir_intrinsic_instr *store_reg = nir_store_reg_for_def(&def);
       bool is_scalar = false;
    
       if (def.parent_instr->type == nir_instr_type_intrinsic &&
           store_reg == NULL) {
          const nir_intrinsic_instr *instr =
             nir_instr_as_intrinsic(def.parent_instr);
    
          switch (instr->intrinsic) {
          case nir_intrinsic_load_btd_global_arg_addr_intel:
          case nir_intrinsic_load_btd_local_arg_addr_intel:
          case nir_intrinsic_load_btd_shader_type_intel:
          case nir_intrinsic_load_global_constant_uniform_block_intel:
          case nir_intrinsic_load_inline_data_intel:
          case nir_intrinsic_load_reloc_const_intel:
          case nir_intrinsic_load_ssbo_uniform_block_intel:
          case nir_intrinsic_load_ubo_uniform_block_intel:
          case nir_intrinsic_load_workgroup_id:
             is_scalar = true;
             break;
    
          case nir_intrinsic_load_ubo:
             is_scalar = get_nir_src(ntb, instr->src[1]).is_scalar;
             break;
    
          case nir_intrinsic_load_uniform:
          case nir_intrinsic_load_push_constant:
             is_scalar = get_nir_src(ntb, instr->src[0]).is_scalar;
             break;
    
          case nir_intrinsic_ballot:
          case nir_intrinsic_resource_intel:
             is_scalar = !def.divergent;
             break;
    
          default:
             break;
          }
    
          /* This cannot be is_scalar if NIR thought it was divergent. */
          assert(!(is_scalar && def.divergent));
       } else if (def.parent_instr->type == nir_instr_type_alu) {
          is_scalar = store_reg == NULL && all_sources_uniform && !def.divergent;
       }
    
       const brw_builder &bld = is_scalar ? ntb.bld.scalar_group() : ntb.bld;
    
       if (!store_reg) {
          const brw_reg_type reg_type =
             brw_type_with_size(def.bit_size == 8 ? BRW_TYPE_D : BRW_TYPE_F,
                                def.bit_size);
          ntb.ssa_values[def.index] =
             bld.vgrf(reg_type, def.num_components);
    
          ntb.ssa_values[def.index].is_scalar = is_scalar;
    
          if (def.bit_size * bld.dispatch_width() < 8 * REG_SIZE)
             bld.UNDEF(ntb.ssa_values[def.index]);
    
          return ntb.ssa_values[def.index];
       } else {
          nir_intrinsic_instr *decl_reg =
             nir_reg_get_decl(store_reg->src[1].ssa);
          /* We don't handle indirects on locals */
          assert(nir_intrinsic_base(store_reg) == 0);
          assert(store_reg->intrinsic != nir_intrinsic_store_reg_indirect);
          assert(!is_scalar);
          return ntb.ssa_values[decl_reg->def.index];
       }
    }
    
    static nir_component_mask_t
    get_nir_write_mask(const nir_def &def)
    {
       nir_intrinsic_instr *store_reg = nir_store_reg_for_def(&def);
       if (!store_reg) {
          return nir_component_mask(def.num_components);
       } else {
          return nir_intrinsic_write_mask(store_reg);
       }
    }
    
    static fs_inst *
    emit_pixel_interpolater_send(const brw_builder &bld,
                                 enum opcode opcode,
                                 const brw_reg &dst,
                                 const brw_reg &src,
                                 const brw_reg &desc,
                                 const brw_reg &flag_reg,
                                 glsl_interp_mode interpolation)
    {
       struct brw_wm_prog_data *wm_prog_data =
          brw_wm_prog_data(bld.shader->prog_data);
    
       brw_reg srcs[INTERP_NUM_SRCS];
    
       if (src.is_scalar) {
          srcs[INTERP_SRC_OFFSET] = bld.vgrf(src.type, 2);
          brw_combine_with_vec(bld, srcs[INTERP_SRC_OFFSET], src, 2);
       } else {
          srcs[INTERP_SRC_OFFSET] = src;
       }
    
       srcs[INTERP_SRC_MSG_DESC]     = desc;
       srcs[INTERP_SRC_DYNAMIC_MODE] = flag_reg;
    
       fs_inst *inst = bld.emit(opcode, dst, srcs, INTERP_NUM_SRCS);
       /* 2 floats per slot returned */
       inst->size_written = 2 * dst.component_size(inst->exec_size);
       if (interpolation == INTERP_MODE_NOPERSPECTIVE) {
          inst->pi_noperspective = true;
          /* TGL BSpec says:
           *     This field cannot be set to "Linear Interpolation"
           *     unless Non-Perspective Barycentric Enable in 3DSTATE_CLIP is enabled"
           */
          wm_prog_data->uses_nonperspective_interp_modes = true;
       }
    
       wm_prog_data->pulls_bary = true;
    
       return inst;
    }
    
    /**
     * Return the specified component \p subreg of a per-polygon PS
     * payload register for the polygon corresponding to each channel
     * specified in the provided \p bld.
     *
     * \p reg specifies the payload register in REG_SIZE units for the
     * first polygon dispatched to the thread.  This function requires
     * that subsequent registers on the payload contain the corresponding
     * register for subsequent polygons, one GRF register per polygon, if
     * multiple polygons are being processed by the same PS thread.
     *
     * This can be used to access the value of a "Source Depth and/or W
     * Attribute Vertex Deltas", "Perspective Bary Planes" or
     * "Non-Perspective Bary Planes" payload field conveniently for
     * multiple polygons as a single brw_reg.
     */
    static brw_reg
    fetch_polygon_reg(const brw_builder &bld, unsigned reg, unsigned subreg)
    {
       const fs_visitor *shader = bld.shader;
       assert(shader->stage == MESA_SHADER_FRAGMENT);
    
       const struct intel_device_info *devinfo = shader->devinfo;
       const unsigned poly_width = shader->dispatch_width / shader->max_polygons;
       const unsigned poly_idx = bld.group() / poly_width;
       assert(bld.group() % poly_width == 0);
    
       if (bld.dispatch_width() > poly_width) {
          assert(bld.dispatch_width() <= 2 * poly_width);
          const unsigned reg_size = reg_unit(devinfo) * REG_SIZE;
          const unsigned vstride = reg_size / brw_type_size_bytes(BRW_TYPE_F);
          return stride(brw_vec1_grf(reg + reg_unit(devinfo) * poly_idx, subreg),
                        vstride, poly_width, 0);
       } else {
          return brw_vec1_grf(reg + reg_unit(devinfo) * poly_idx, subreg);
       }
    }
    
    /**
     * Interpolate per-polygon barycentrics at a specific offset relative
     * to each channel fragment coordinates, optionally using
     * perspective-correct interpolation if requested.  This is mostly
     * useful as replacement for the PI shared function that existed on
     * platforms prior to Xe2, but is expected to work on earlier
     * platforms since we can get the required polygon setup information
     * from the thread payload as far back as ICL.
     */
    static void
    emit_pixel_interpolater_alu_at_offset(const brw_builder &bld,
                                          const brw_reg &dst,
                                          const brw_reg &offs,
                                          glsl_interp_mode interpolation)
    {
       const fs_visitor *shader = bld.shader;
       assert(shader->stage == MESA_SHADER_FRAGMENT);
    
       const intel_device_info *devinfo = shader->devinfo;
       assert(devinfo->ver >= 11);
    
       const fs_thread_payload &payload = shader->fs_payload();
       const struct brw_wm_prog_data *wm_prog_data =
          brw_wm_prog_data(shader->prog_data);
    
       if (interpolation == INTERP_MODE_NOPERSPECTIVE) {
          assert(wm_prog_data->uses_npc_bary_coefficients &&
                 wm_prog_data->uses_nonperspective_interp_modes);
       } else {
          assert(interpolation == INTERP_MODE_SMOOTH);
          assert(wm_prog_data->uses_pc_bary_coefficients &&
                 wm_prog_data->uses_depth_w_coefficients);
       }
    
       /* Account for half-pixel X/Y coordinate offset. */
       const brw_reg off_x = bld.vgrf(BRW_TYPE_F);
       bld.ADD(off_x, offset(offs, bld, 0), brw_imm_f(0.5));
    
       const brw_reg off_y = bld.vgrf(BRW_TYPE_F);
       bld.ADD(off_y, offset(offs, bld, 1), brw_imm_f(0.5));
    
       /* Process no more than two polygons at a time to avoid hitting
        * regioning restrictions.
        */
       const unsigned poly_width = shader->dispatch_width / shader->max_polygons;
    
       for (unsigned i = 0; i < DIV_ROUND_UP(shader->max_polygons, 2); i++) {
          const brw_builder ibld = bld.group(MIN2(bld.dispatch_width(), 2 * poly_width), i);
    
          /* Fetch needed parameters from the thread payload. */
          const unsigned bary_coef_reg = interpolation == INTERP_MODE_NOPERSPECTIVE ?
             payload.npc_bary_coef_reg : payload.pc_bary_coef_reg;
          const brw_reg start_x = devinfo->ver < 12 ? fetch_polygon_reg(ibld, 1, 1) :
             fetch_polygon_reg(ibld, bary_coef_reg,
                               devinfo->ver >= 20 ? 6 : 2);
          const brw_reg start_y = devinfo->ver < 12 ? fetch_polygon_reg(ibld, 1, 6) :
             fetch_polygon_reg(ibld, bary_coef_reg,
                               devinfo->ver >= 20 ? 7 : 6);
    
          const brw_reg bary1_c0 = fetch_polygon_reg(ibld, bary_coef_reg,
                                                    devinfo->ver >= 20 ? 2 : 3);
          const brw_reg bary1_cx = fetch_polygon_reg(ibld, bary_coef_reg, 1);
          const brw_reg bary1_cy = fetch_polygon_reg(ibld, bary_coef_reg, 0);
    
          const brw_reg bary2_c0 = fetch_polygon_reg(ibld, bary_coef_reg,
                                                    devinfo->ver >= 20 ? 5 : 7);
          const brw_reg bary2_cx = fetch_polygon_reg(ibld, bary_coef_reg,
                                                    devinfo->ver >= 20 ? 4 : 5);
          const brw_reg bary2_cy = fetch_polygon_reg(ibld, bary_coef_reg,
                                                    devinfo->ver >= 20 ? 3 : 4);
    
          const brw_reg rhw_c0 = devinfo->ver >= 20 ?
             fetch_polygon_reg(ibld, payload.depth_w_coef_reg + 1, 5) :
             fetch_polygon_reg(ibld, payload.depth_w_coef_reg, 7);
          const brw_reg rhw_cx = devinfo->ver >= 20 ?
             fetch_polygon_reg(ibld, payload.depth_w_coef_reg + 1, 4) :
             fetch_polygon_reg(ibld, payload.depth_w_coef_reg, 5);
          const brw_reg rhw_cy = devinfo->ver >= 20 ?
             fetch_polygon_reg(ibld, payload.depth_w_coef_reg + 1, 3) :
             fetch_polygon_reg(ibld, payload.depth_w_coef_reg, 4);
    
          /* Compute X/Y coordinate deltas relative to the origin of the polygon. */
          const brw_reg delta_x = ibld.vgrf(BRW_TYPE_F);
          ibld.ADD(delta_x, offset(shader->pixel_x, ibld, i), negate(start_x));
          ibld.ADD(delta_x, delta_x, offset(off_x, ibld, i));
    
          const brw_reg delta_y = ibld.vgrf(BRW_TYPE_F);
          ibld.ADD(delta_y, offset(shader->pixel_y, ibld, i), negate(start_y));
          ibld.ADD(delta_y, delta_y, offset(off_y, ibld, i));
    
          /* Evaluate the plane equations obtained above for the
           * barycentrics and RHW coordinate at the offset specified for
           * each channel.  Limit arithmetic to acc_width in order to
           * allow the accumulator to be used for linear interpolation.
           */
          const unsigned acc_width = 16 * reg_unit(devinfo);
          const brw_reg rhw = ibld.vgrf(BRW_TYPE_F);
          const brw_reg bary1 = ibld.vgrf(BRW_TYPE_F);
          const brw_reg bary2 = ibld.vgrf(BRW_TYPE_F);
    
          for (unsigned j = 0; j < DIV_ROUND_UP(ibld.dispatch_width(), acc_width); j++) {
             const brw_builder jbld = ibld.group(MIN2(ibld.dispatch_width(), acc_width), j);
             const brw_reg acc = suboffset(brw_acc_reg(16), jbld.group() % acc_width);
    
             if (interpolation != INTERP_MODE_NOPERSPECTIVE) {
                jbld.MAD(acc, horiz_offset(rhw_c0, acc_width * j),
                         horiz_offset(rhw_cx, acc_width * j), offset(delta_x, jbld, j));
                jbld.MAC(offset(rhw, jbld, j),
                         horiz_offset(rhw_cy, acc_width * j), offset(delta_y, jbld, j));
             }
    
             jbld.MAD(acc, horiz_offset(bary1_c0, acc_width * j),
                      horiz_offset(bary1_cx, acc_width * j), offset(delta_x, jbld, j));
             jbld.MAC(offset(bary1, jbld, j),
                      horiz_offset(bary1_cy, acc_width * j), offset(delta_y, jbld, j));
    
             jbld.MAD(acc, horiz_offset(bary2_c0, acc_width * j),
                      horiz_offset(bary2_cx, acc_width * j), offset(delta_x, jbld, j));
             jbld.MAC(offset(bary2, jbld, j),
                      horiz_offset(bary2_cy, acc_width * j), offset(delta_y, jbld, j));
          }
    
          /* Scale the results dividing by the interpolated RHW coordinate
           * if the interpolation is required to be perspective-correct.
           */
          if (interpolation == INTERP_MODE_NOPERSPECTIVE) {
             ibld.MOV(offset(dst, ibld, i), bary1);
             ibld.MOV(offset(offset(dst, bld, 1), ibld, i), bary2);
          } else {
             const brw_reg w = ibld.vgrf(BRW_TYPE_F);
             ibld.emit(SHADER_OPCODE_RCP, w, rhw);
             ibld.MUL(offset(dst, ibld, i), bary1, w);
             ibld.MUL(offset(offset(dst, bld, 1), ibld, i), bary2, w);
          }
       }
    }
    
    /**
     * Interpolate per-polygon barycentrics at a specified sample index,
     * optionally using perspective-correct interpolation if requested.
     * This is mostly useful as replacement for the PI shared function
     * that existed on platforms prior to Xe2, but is expected to work on
     * earlier platforms since we can get the required polygon setup
     * information from the thread payload as far back as ICL.
     */
    static void
    emit_pixel_interpolater_alu_at_sample(const brw_builder &bld,
                                          const brw_reg &dst,
                                          const brw_reg &idx,
                                          glsl_interp_mode interpolation)
    {
       const fs_thread_payload &payload = bld.shader->fs_payload();
       const struct brw_wm_prog_data *wm_prog_data =
          brw_wm_prog_data(bld.shader->prog_data);
       const brw_builder ubld = bld.exec_all().group(16, 0);
       const brw_reg sample_offs_xy = ubld.vgrf(BRW_TYPE_UD);
       assert(wm_prog_data->uses_sample_offsets);
    
       /* Interleave the X/Y coordinates of each sample in order to allow
        * a single indirect look-up, by using a MOV for the 16 X
        * coordinates, then another MOV for the 16 Y coordinates.
        */
       for (unsigned i = 0; i < 2; i++) {
          const brw_reg reg = retype(brw_vec16_grf(payload.sample_offsets_reg, 4 * i),
                                    BRW_TYPE_UB);
          ubld.MOV(subscript(sample_offs_xy, BRW_TYPE_UW, i), reg);
       }
    
       /* Use indirect addressing to fetch the X/Y offsets of the sample
        * index provided for each channel.
        */
       const brw_reg idx_b = bld.vgrf(BRW_TYPE_UD);
       bld.MUL(idx_b, idx, brw_imm_ud(brw_type_size_bytes(BRW_TYPE_UD)));
    
       const brw_reg off_xy = bld.vgrf(BRW_TYPE_UD);
       bld.emit(SHADER_OPCODE_MOV_INDIRECT, off_xy, component(sample_offs_xy, 0),
                idx_b, brw_imm_ud(16 * brw_type_size_bytes(BRW_TYPE_UD)));
    
       /* Convert the selected fixed-point offsets to floating-point
        * offsets.
        */
       const brw_reg offs = bld.vgrf(BRW_TYPE_F, 2);
    
       for (unsigned i = 0; i < 2; i++) {
          const brw_reg tmp = bld.vgrf(BRW_TYPE_F);
          bld.MOV(tmp, subscript(off_xy, BRW_TYPE_UW, i));
          bld.MUL(tmp, tmp, brw_imm_f(0.0625));
          bld.ADD(offset(offs, bld, i), tmp, brw_imm_f(-0.5));
       }
    
       /* Interpolate at the resulting offsets. */
       emit_pixel_interpolater_alu_at_offset(bld, dst, offs, interpolation);
    }
    
    /**
     * Computes 1 << x, given a D/UD register containing some value x.
     */
    static brw_reg
    intexp2(const brw_builder &bld, const brw_reg &x)
    {
       assert(x.type == BRW_TYPE_UD || x.type == BRW_TYPE_D);
    
       return bld.SHL(bld.MOV(retype(brw_imm_d(1), x.type)), x);
    }
    
    static void
    emit_gs_end_primitive(nir_to_brw_state &ntb, const nir_src &vertex_count_nir_src)
    {
       fs_visitor &s = ntb.s;
       assert(s.stage == MESA_SHADER_GEOMETRY);
    
       struct brw_gs_prog_data *gs_prog_data = brw_gs_prog_data(s.prog_data);
    
       if (s.gs_compile->control_data_header_size_bits == 0)
          return;
    
       /* We can only do EndPrimitive() functionality when the control data
        * consists of cut bits.  Fortunately, the only time it isn't is when the
        * output type is points, in which case EndPrimitive() is a no-op.
        */
       if (gs_prog_data->control_data_format !=
           GFX7_GS_CONTROL_DATA_FORMAT_GSCTL_CUT) {
          return;
       }
    
       /* Cut bits use one bit per vertex. */
       assert(s.gs_compile->control_data_bits_per_vertex == 1);
    
       brw_reg vertex_count = get_nir_src(ntb, vertex_count_nir_src);
       vertex_count.type = BRW_TYPE_UD;
    
       /* Cut bit n should be set to 1 if EndPrimitive() was called after emitting
        * vertex n, 0 otherwise.  So all we need to do here is mark bit
        * (vertex_count - 1) % 32 in the cut_bits register to indicate that
        * EndPrimitive() was called after emitting vertex (vertex_count - 1);
        * vec4_gs_visitor::emit_control_data_bits() will take care of the rest.
        *
        * Note that if EndPrimitive() is called before emitting any vertices, this
        * will cause us to set bit 31 of the control_data_bits register to 1.
        * That's fine because:
        *
        * - If max_vertices < 32, then vertex number 31 (zero-based) will never be
        *   output, so the hardware will ignore cut bit 31.
        *
        * - If max_vertices == 32, then vertex number 31 is guaranteed to be the
        *   last vertex, so setting cut bit 31 has no effect (since the primitive
        *   is automatically ended when the GS terminates).
        *
        * - If max_vertices > 32, then the ir_emit_vertex visitor will reset the
        *   control_data_bits register to 0 when the first vertex is emitted.
        */
    
       const brw_builder abld = ntb.bld.annotate("end primitive");
    
       /* control_data_bits |= 1 << ((vertex_count - 1) % 32) */
       brw_reg prev_count = abld.ADD(vertex_count, brw_imm_ud(0xffffffffu));
       brw_reg mask = intexp2(abld, prev_count);
       /* Note: we're relying on the fact that the GEN SHL instruction only pays
        * attention to the lower 5 bits of its second source argument, so on this
        * architecture, 1 << (vertex_count - 1) is equivalent to 1 <<
        * ((vertex_count - 1) % 32).
        */
       abld.OR(s.control_data_bits, s.control_data_bits, mask);
    }
    
    brw_reg
    fs_visitor::gs_urb_per_slot_dword_index(const brw_reg &vertex_count)
    {
       /* We use a single UD register to accumulate control data bits (32 bits
        * for each of the SIMD8 channels).  So we need to write a DWord (32 bits)
        * at a time.
        *
        * On platforms < Xe2:
        *    Unfortunately,the URB_WRITE_SIMD8 message uses 128-bit (OWord)
        *    offsets.  We have select a 128-bit group via the Global and Per-Slot
        *    Offsets, then use the Channel Mask phase to enable/disable which DWord
        *    within that group to write.  (Remember, different SIMD8 channels may
        *    have emitted different numbers of vertices, so we may need per-slot
        *    offsets.)
        *
        *    Channel masking presents an annoying problem: we may have to replicate
        *    the data up to 4 times:
        *
        *    Msg = Handles, Per-Slot Offsets, Channel Masks, Data, Data, Data,
        *          Data.
        *
        *    To avoid penalizing shaders that emit a small number of vertices, we
        *    can avoid these sometimes: if the size of the control data header is
        *    <= 128 bits, then there is only 1 OWord.  All SIMD8 channels will land
        *    land in the same 128-bit group, so we can skip per-slot offsets.
        *
        *    Similarly, if the control data header is <= 32 bits, there is only one
        *    DWord, so we can skip channel masks.
        */
       const brw_builder bld = brw_builder(this).at_end();
       const brw_builder abld = bld.annotate("urb per slot offset");
    
       /* Figure out which DWord we're trying to write to using the formula:
        *
        *    dword_index = (vertex_count - 1) * bits_per_vertex / 32
        *
        * Since bits_per_vertex is a power of two, and is known at compile
        * time, this can be optimized to:
        *
        *    dword_index = (vertex_count - 1) >> (6 - log2(bits_per_vertex))
        */
       brw_reg prev_count = abld.ADD(vertex_count, brw_imm_ud(0xffffffffu));
       unsigned log2_bits_per_vertex =
          util_last_bit(gs_compile->control_data_bits_per_vertex);
       return abld.SHR(prev_count, brw_imm_ud(6u - log2_bits_per_vertex));
    }
    
    brw_reg
    fs_visitor::gs_urb_channel_mask(const brw_reg &dword_index)
    {
       brw_reg channel_mask;
    
       /* Xe2+ can do URB loads with a byte offset, so we don't need to
        * construct a channel mask.
        */
       if (devinfo->ver >= 20)
          return channel_mask;
    
       /* Channel masking presents an annoying problem: we may have to replicate
        * the data up to 4 times:
        *
        * Msg = Handles, Per-Slot Offsets, Channel Masks, Data, Data, Data, Data.
        *
        * To avoid penalizing shaders that emit a small number of vertices, we
        * can avoid these sometimes: if the size of the control data header is
        * <= 128 bits, then there is only 1 OWord.  All SIMD8 channels will land
        * land in the same 128-bit group, so we can skip per-slot offsets.
        *
        * Similarly, if the control data header is <= 32 bits, there is only one
        * DWord, so we can skip channel masks.
        */
       if (gs_compile->control_data_header_size_bits <= 32)
          return channel_mask;
    
       const brw_builder bld = brw_builder(this).at_end();
       const brw_builder ubld = bld.exec_all();
    
       /* Set the channel masks to 1 << (dword_index % 4), so that we'll
        * write to the appropriate DWORD within the OWORD.
        */
       brw_reg channel = ubld.AND(dword_index, brw_imm_ud(3u));
       /* Then the channel masks need to be in bits 23:16. */
       return ubld.SHL(intexp2(ubld, channel), brw_imm_ud(16u));
    }
    
    void
    fs_visitor::emit_gs_control_data_bits(const brw_reg &vertex_count)
    {
       assert(stage == MESA_SHADER_GEOMETRY);
       assert(gs_compile->control_data_bits_per_vertex != 0);
    
       const struct brw_gs_prog_data *gs_prog_data = brw_gs_prog_data(prog_data);
    
       const brw_builder bld = brw_builder(this).at_end();
       const brw_builder abld = bld.annotate("emit control data bits");
    
       brw_reg dword_index = gs_urb_per_slot_dword_index(vertex_count);
       brw_reg channel_mask = gs_urb_channel_mask(dword_index);
       brw_reg per_slot_offset;
    
       const unsigned max_control_data_header_size_bits =
          devinfo->ver >= 20 ? 32 : 128;
    
       if (gs_compile->control_data_header_size_bits > max_control_data_header_size_bits) {
          /* Convert dword_index to bytes on Xe2+ since LSC can do operate on byte
           * offset granularity.
           */
          if (devinfo->ver >= 20) {
             per_slot_offset = abld.SHL(dword_index, brw_imm_ud(2u));
          } else {
             /* Set the per-slot offset to dword_index / 4, so that we'll write to
              * the appropriate OWord within the control data header.
              */
             per_slot_offset = abld.SHR(dword_index, brw_imm_ud(2u));
          }
       }
    
       /* If there are channel masks, add 3 extra copies of the data. */
       const unsigned length = 1 + 3 * unsigned(channel_mask.file != BAD_FILE);
       assert(length <= 4);
       brw_reg sources[4];
    
       for (unsigned i = 0; i < length; i++)
          sources[i] = this->control_data_bits;
    
       brw_reg srcs[URB_LOGICAL_NUM_SRCS];
       srcs[URB_LOGICAL_SRC_HANDLE] = gs_payload().urb_handles;
       srcs[URB_LOGICAL_SRC_PER_SLOT_OFFSETS] = per_slot_offset;
       srcs[URB_LOGICAL_SRC_CHANNEL_MASK] = channel_mask;
       srcs[URB_LOGICAL_SRC_DATA] = bld.vgrf(BRW_TYPE_F, length);
       srcs[URB_LOGICAL_SRC_COMPONENTS] = brw_imm_ud(length);
       abld.LOAD_PAYLOAD(srcs[URB_LOGICAL_SRC_DATA], sources, length, 0);
    
       fs_inst *inst = abld.emit(SHADER_OPCODE_URB_WRITE_LOGICAL, reg_undef,
                                 srcs, ARRAY_SIZE(srcs));
    
       /* We need to increment Global Offset by 256-bits to make room for
        * Broadwell's extra "Vertex Count" payload at the beginning of the
        * URB entry.  Since this is an OWord message, Global Offset is counted
        * in 128-bit units, so we must set it to 2.
        */
       if (gs_prog_data->static_vertex_count == -1)
          inst->offset = 2;
    }
    
    static void
    set_gs_stream_control_data_bits(nir_to_brw_state &ntb, const brw_reg &vertex_count,
                                    unsigned stream_id)
    {
       fs_visitor &s = ntb.s;
    
       /* control_data_bits |= stream_id << ((2 * (vertex_count - 1)) % 32) */
    
       /* Note: we are calling this *before* increasing vertex_count, so
        * this->vertex_count == vertex_count - 1 in the formula above.
        */
    
       /* Stream mode uses 2 bits per vertex */
       assert(s.gs_compile->control_data_bits_per_vertex == 2);
    
       /* Must be a valid stream */
       assert(stream_id < 4); /* MAX_VERTEX_STREAMS */
    
       /* Control data bits are initialized to 0 so we don't have to set any
        * bits when sending vertices to stream 0.
        */
       if (stream_id == 0)
          return;
    
       const brw_builder abld = ntb.bld.annotate("set stream control data bits");
    
       /* reg::sid = stream_id */
       brw_reg sid = abld.MOV(brw_imm_ud(stream_id));
    
       /* reg:shift_count = 2 * (vertex_count - 1) */
       brw_reg shift_count = abld.SHL(vertex_count, brw_imm_ud(1u));
    
       /* Note: we're relying on the fact that the GEN SHL instruction only pays
        * attention to the lower 5 bits of its second source argument, so on this
        * architecture, stream_id << 2 * (vertex_count - 1) is equivalent to
        * stream_id << ((2 * (vertex_count - 1)) % 32).
        */
       brw_reg mask = abld.SHL(sid, shift_count);
       abld.OR(s.control_data_bits, s.control_data_bits, mask);
    }
    
    static void
    emit_gs_vertex(nir_to_brw_state &ntb, const nir_src &vertex_count_nir_src,
                   unsigned stream_id)
    {
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_GEOMETRY);
    
       struct brw_gs_prog_data *gs_prog_data = brw_gs_prog_data(s.prog_data);
    
       brw_reg vertex_count = get_nir_src(ntb, vertex_count_nir_src);
       vertex_count.type = BRW_TYPE_UD;
    
       /* Haswell and later hardware ignores the "Render Stream Select" bits
        * from the 3DSTATE_STREAMOUT packet when the SOL stage is disabled,
        * and instead sends all primitives down the pipeline for rasterization.
        * If the SOL stage is enabled, "Render Stream Select" is honored and
        * primitives bound to non-zero streams are discarded after stream output.
        *
        * Since the only purpose of primives sent to non-zero streams is to
        * be recorded by transform feedback, we can simply discard all geometry
        * bound to these streams when transform feedback is disabled.
        */
       if (stream_id > 0 && !s.nir->info.has_transform_feedback_varyings)
          return;
    
       /* If we're outputting 32 control data bits or less, then we can wait
        * until the shader is over to output them all.  Otherwise we need to
        * output them as we go.  Now is the time to do it, since we're about to
        * output the vertex_count'th vertex, so it's guaranteed that the
        * control data bits associated with the (vertex_count - 1)th vertex are
        * correct.
        */
       if (s.gs_compile->control_data_header_size_bits > 32) {
          const brw_builder abld =
             ntb.bld.annotate("emit vertex: emit control data bits");
    
          /* Only emit control data bits if we've finished accumulating a batch
           * of 32 bits.  This is the case when:
           *
           *     (vertex_count * bits_per_vertex) % 32 == 0
           *
           * (in other words, when the last 5 bits of vertex_count *
           * bits_per_vertex are 0).  Assuming bits_per_vertex == 2^n for some
           * integer n (which is always the case, since bits_per_vertex is
           * always 1 or 2), this is equivalent to requiring that the last 5-n
           * bits of vertex_count are 0:
           *
           *     vertex_count & (2^(5-n) - 1) == 0
           *
           * 2^(5-n) == 2^5 / 2^n == 32 / bits_per_vertex, so this is
           * equivalent to:
           *
           *     vertex_count & (32 / bits_per_vertex - 1) == 0
           *
           * TODO: If vertex_count is an immediate, we could do some of this math
           *       at compile time...
           */
          fs_inst *inst =
             abld.AND(ntb.bld.null_reg_d(), vertex_count,
                      brw_imm_ud(32u / s.gs_compile->control_data_bits_per_vertex - 1u));
          inst->conditional_mod = BRW_CONDITIONAL_Z;
    
          abld.IF(BRW_PREDICATE_NORMAL);
          /* If vertex_count is 0, then no control data bits have been
           * accumulated yet, so we can skip emitting them.
           */
          abld.CMP(ntb.bld.null_reg_d(), vertex_count, brw_imm_ud(0u),
                   BRW_CONDITIONAL_NEQ);
          abld.IF(BRW_PREDICATE_NORMAL);
          s.emit_gs_control_data_bits(vertex_count);
          abld.emit(BRW_OPCODE_ENDIF);
    
          /* Reset control_data_bits to 0 so we can start accumulating a new
           * batch.
           *
           * Note: in the case where vertex_count == 0, this neutralizes the
           * effect of any call to EndPrimitive() that the shader may have
           * made before outputting its first vertex.
           */
          abld.exec_all().MOV(s.control_data_bits, brw_imm_ud(0u));
          abld.emit(BRW_OPCODE_ENDIF);
       }
    
       s.emit_urb_writes(vertex_count);
    
       /* In stream mode we have to set control data bits for all vertices
        * unless we have disabled control data bits completely (which we do
        * do for MESA_PRIM_POINTS outputs that don't use streams).
        */
       if (s.gs_compile->control_data_header_size_bits > 0 &&
           gs_prog_data->control_data_format ==
              GFX7_GS_CONTROL_DATA_FORMAT_GSCTL_SID) {
          set_gs_stream_control_data_bits(ntb, vertex_count, stream_id);
       }
    }
    
    static void
    brw_combine_with_vec(const brw_builder &bld, const brw_reg &dst,
                         const brw_reg &src, unsigned n)
    {
       assert(n <= NIR_MAX_VEC_COMPONENTS);
       brw_reg comps[NIR_MAX_VEC_COMPONENTS];
       for (unsigned i = 0; i < n; i++)
          comps[i] = offset(src, bld, i);
       bld.VEC(dst, comps, n);
    }
    
    static void
    emit_gs_input_load(nir_to_brw_state &ntb, const brw_reg &dst,
                       const nir_src &vertex_src,
                       unsigned base_offset,
                       const nir_src &offset_src,
                       unsigned num_components,
                       unsigned first_component)
    {
       const brw_builder &bld = ntb.bld;
       const struct intel_device_info *devinfo = ntb.devinfo;
    
       fs_visitor &s = ntb.s;
    
       assert(brw_type_size_bytes(dst.type) == 4);
       struct brw_gs_prog_data *gs_prog_data = brw_gs_prog_data(s.prog_data);
       const unsigned push_reg_count = gs_prog_data->base.urb_read_length * 8;
    
       /* TODO: figure out push input layout for invocations == 1 */
       if (gs_prog_data->invocations == 1 &&
           nir_src_is_const(offset_src) && nir_src_is_const(vertex_src) &&
           4 * (base_offset + nir_src_as_uint(offset_src)) < push_reg_count) {
          int imm_offset = (base_offset + nir_src_as_uint(offset_src)) * 4 +
                           nir_src_as_uint(vertex_src) * push_reg_count;
    
          const brw_reg attr = offset(brw_attr_reg(0, dst.type), bld,
                                      first_component + imm_offset);
          brw_combine_with_vec(bld, dst, attr, num_components);
          return;
       }
    
       /* Resort to the pull model.  Ensure the VUE handles are provided. */
       assert(gs_prog_data->base.include_vue_handles);
    
       brw_reg start = s.gs_payload().icp_handle_start;
       brw_reg icp_handle = ntb.bld.vgrf(BRW_TYPE_UD);
       const unsigned grf_size_bytes = REG_SIZE * reg_unit(devinfo);
    
       if (gs_prog_data->invocations == 1) {
          if (nir_src_is_const(vertex_src)) {
             /* The vertex index is constant; just select the proper URB handle. */
             icp_handle =
                byte_offset(start, nir_src_as_uint(vertex_src) * grf_size_bytes);
          } else {
             /* The vertex index is non-constant.  We need to use indirect
              * addressing to fetch the proper URB handle.
              *
              * First, we start with the sequence <7, 6, 5, 4, 3, 2, 1, 0>
              * indicating that channel <n> should read the handle from
              * DWord <n>.  We convert that to bytes by multiplying by 4.
              *
              * Next, we convert the vertex index to bytes by multiplying
              * by 32/64 (shifting by 5/6), and add the two together.  This is
              * the final indirect byte offset.
              */
             brw_reg sequence = bld.LOAD_SUBGROUP_INVOCATION();
    
             /* channel_offsets = 4 * sequence = <28, 24, 20, 16, 12, 8, 4, 0> */
             brw_reg channel_offsets = bld.SHL(sequence, brw_imm_ud(2u));
             /* Convert vertex_index to bytes (multiply by 32/64) */
             assert(util_is_power_of_two_nonzero(grf_size_bytes)); /* for ffs() */
             brw_reg vertex_offset_bytes =
                bld.SHL(retype(get_nir_src(ntb, vertex_src), BRW_TYPE_UD),
                        brw_imm_ud(ffs(grf_size_bytes) - 1));
             brw_reg icp_offset_bytes =
                bld.ADD(vertex_offset_bytes, channel_offsets);
    
             /* Use first_icp_handle as the base offset.  There is one register
              * of URB handles per vertex, so inform the register allocator that
              * we might read up to nir->info.gs.vertices_in registers.
              */
             bld.emit(SHADER_OPCODE_MOV_INDIRECT, icp_handle, start,
                      brw_reg(icp_offset_bytes),
                      brw_imm_ud(s.nir->info.gs.vertices_in * grf_size_bytes));
          }
       } else {
          assert(gs_prog_data->invocations > 1);
    
          if (nir_src_is_const(vertex_src)) {
             unsigned vertex = nir_src_as_uint(vertex_src);
             bld.MOV(icp_handle, component(start, vertex));
          } else {
             /* The vertex index is non-constant.  We need to use indirect
              * addressing to fetch the proper URB handle.
              *
              * Convert vertex_index to bytes (multiply by 4)
              */
             brw_reg icp_offset_bytes =
                bld.SHL(retype(get_nir_src(ntb, vertex_src), BRW_TYPE_UD),
                        brw_imm_ud(2u));
    
             /* Use first_icp_handle as the base offset.  There is one DWord
              * of URB handles per vertex, so inform the register allocator that
              * we might read up to ceil(nir->info.gs.vertices_in / 8) registers.
              */
             bld.emit(SHADER_OPCODE_MOV_INDIRECT, icp_handle, start,
                      brw_reg(icp_offset_bytes),
                      brw_imm_ud(DIV_ROUND_UP(s.nir->info.gs.vertices_in, 8) *
                                 grf_size_bytes));
          }
       }
    
       fs_inst *inst;
       brw_reg indirect_offset = get_nir_src(ntb, offset_src);
    
       if (nir_src_is_const(offset_src)) {
          brw_reg srcs[URB_LOGICAL_NUM_SRCS];
          srcs[URB_LOGICAL_SRC_HANDLE] = icp_handle;
    
          /* Constant indexing - use global offset. */
          if (first_component != 0) {
             unsigned read_components = num_components + first_component;
             brw_reg tmp = bld.vgrf(dst.type, read_components);
             inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, tmp, srcs,
                             ARRAY_SIZE(srcs));
             inst->size_written = read_components *
                                  tmp.component_size(inst->exec_size);
             brw_combine_with_vec(bld, dst, offset(tmp, bld, first_component),
                                  num_components);
          } else {
             inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, dst, srcs,
                             ARRAY_SIZE(srcs));
             inst->size_written = num_components *
                                  dst.component_size(inst->exec_size);
          }
          inst->offset = base_offset + nir_src_as_uint(offset_src);
       } else {
          /* Indirect indexing - use per-slot offsets as well. */
          unsigned read_components = num_components + first_component;
          brw_reg tmp = bld.vgrf(dst.type, read_components);
    
          /* Convert oword offset to bytes on Xe2+ */
          if (devinfo->ver >= 20)
             indirect_offset = bld.SHL(indirect_offset, brw_imm_ud(4u));
    
          brw_reg srcs[URB_LOGICAL_NUM_SRCS];
          srcs[URB_LOGICAL_SRC_HANDLE] = icp_handle;
          srcs[URB_LOGICAL_SRC_PER_SLOT_OFFSETS] = indirect_offset;
    
          if (first_component != 0) {
             inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, tmp,
                             srcs, ARRAY_SIZE(srcs));
             inst->size_written = read_components *
                                  tmp.component_size(inst->exec_size);
             brw_combine_with_vec(bld, dst, offset(tmp, bld, first_component),
                                  num_components);
          } else {
             inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, dst,
                             srcs, ARRAY_SIZE(srcs));
             inst->size_written = num_components *
                                  dst.component_size(inst->exec_size);
          }
          inst->offset = base_offset;
       }
    }
    
    static brw_reg
    get_indirect_offset(nir_to_brw_state &ntb, nir_intrinsic_instr *instr)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       nir_src *offset_src = nir_get_io_offset_src(instr);
    
       if (nir_src_is_const(*offset_src)) {
          /* The only constant offset we should find is 0.  brw_nir.c's
           * add_const_offset_to_base() will fold other constant offsets
           * into the "base" index.
           */
          assert(nir_src_as_uint(*offset_src) == 0);
          return brw_reg();
       }
    
       brw_reg offset = get_nir_src(ntb, *offset_src);
    
       if (devinfo->ver < 20)
          return offset;
    
       /* Convert Owords (16-bytes) to bytes */
       return ntb.bld.SHL(retype(offset, BRW_TYPE_UD), brw_imm_ud(4u));
    }
    
    static void
    fs_nir_emit_vs_intrinsic(nir_to_brw_state &ntb,
                             nir_intrinsic_instr *instr)
    {
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
       assert(s.stage == MESA_SHADER_VERTEX);
    
       brw_reg dest;
       if (nir_intrinsic_infos[instr->intrinsic].has_dest)
          dest = get_nir_def(ntb, instr->def);
    
       switch (instr->intrinsic) {
       case nir_intrinsic_load_vertex_id:
       case nir_intrinsic_load_base_vertex:
          unreachable("should be lowered by nir_lower_system_values()");
    
       case nir_intrinsic_load_input: {
          assert(instr->def.bit_size == 32);
          const brw_reg src = offset(brw_attr_reg(0, dest.type), bld,
                                    nir_intrinsic_base(instr) * 4 +
                                    nir_intrinsic_component(instr) +
                                    nir_src_as_uint(instr->src[0]));
          brw_combine_with_vec(bld, dest, src, instr->num_components);
          break;
       }
    
       case nir_intrinsic_load_vertex_id_zero_base:
       case nir_intrinsic_load_instance_id:
       case nir_intrinsic_load_base_instance:
       case nir_intrinsic_load_draw_id:
       case nir_intrinsic_load_first_vertex:
       case nir_intrinsic_load_is_indexed_draw:
          unreachable("lowered by brw_nir_lower_vs_inputs");
    
       default:
          fs_nir_emit_intrinsic(ntb, bld, instr);
          break;
       }
    }
    
    static brw_reg
    get_tcs_single_patch_icp_handle(nir_to_brw_state &ntb, const brw_builder &bld,
                                    nir_intrinsic_instr *instr)
    {
       fs_visitor &s = ntb.s;
    
       struct brw_tcs_prog_data *tcs_prog_data = brw_tcs_prog_data(s.prog_data);
       const nir_src &vertex_src = instr->src[0];
       nir_intrinsic_instr *vertex_intrin = nir_src_as_intrinsic(vertex_src);
    
       const brw_reg start = s.tcs_payload().icp_handle_start;
    
       brw_reg icp_handle;
    
       if (nir_src_is_const(vertex_src)) {
          /* Emit a MOV to resolve <0,1,0> regioning. */
          unsigned vertex = nir_src_as_uint(vertex_src);
          icp_handle = bld.MOV(component(start, vertex));
       } else if (tcs_prog_data->instances == 1 && vertex_intrin &&
                  vertex_intrin->intrinsic == nir_intrinsic_load_invocation_id) {
          /* For the common case of only 1 instance, an array index of
           * gl_InvocationID means reading the handles from the start.  Skip all
           * the indirect work.
           */
          icp_handle = start;
       } else {
          /* The vertex index is non-constant.  We need to use indirect
           * addressing to fetch the proper URB handle.
           */
          icp_handle = bld.vgrf(BRW_TYPE_UD);
    
          /* Each ICP handle is a single DWord (4 bytes) */
          brw_reg vertex_offset_bytes =
             bld.SHL(retype(get_nir_src(ntb, vertex_src), BRW_TYPE_UD),
                     brw_imm_ud(2u));
    
          /* We might read up to 4 registers. */
          bld.emit(SHADER_OPCODE_MOV_INDIRECT, icp_handle,
                   start, vertex_offset_bytes,
                   brw_imm_ud(4 * REG_SIZE));
       }
    
       return icp_handle;
    }
    
    static brw_reg
    get_tcs_multi_patch_icp_handle(nir_to_brw_state &ntb, const brw_builder &bld,
                                   nir_intrinsic_instr *instr)
    {
       fs_visitor &s = ntb.s;
       const intel_device_info *devinfo = s.devinfo;
    
       struct brw_tcs_prog_key *tcs_key = (struct brw_tcs_prog_key *) s.key;
       const nir_src &vertex_src = instr->src[0];
       const unsigned grf_size_bytes = REG_SIZE * reg_unit(devinfo);
    
       const brw_reg start = s.tcs_payload().icp_handle_start;
    
       if (nir_src_is_const(vertex_src))
          return byte_offset(start, nir_src_as_uint(vertex_src) * grf_size_bytes);
    
       /* The vertex index is non-constant.  We need to use indirect
        * addressing to fetch the proper URB handle.
        *
        * First, we start with the sequence indicating that channel <n>
        * should read the handle from DWord <n>.  We convert that to bytes
        * by multiplying by 4.
        *
        * Next, we convert the vertex index to bytes by multiplying
        * by the GRF size (by shifting), and add the two together.  This is
        * the final indirect byte offset.
        */
       brw_reg sequence = bld.LOAD_SUBGROUP_INVOCATION();
    
       /* Offsets will be 0, 4, 8, ... */
       brw_reg channel_offsets = bld.SHL(sequence, brw_imm_ud(2u));
       /* Convert vertex_index to bytes (multiply by 32) */
       assert(util_is_power_of_two_nonzero(grf_size_bytes)); /* for ffs() */
       brw_reg vertex_offset_bytes =
          bld.SHL(retype(get_nir_src(ntb, vertex_src), BRW_TYPE_UD),
                  brw_imm_ud(ffs(grf_size_bytes) - 1));
       brw_reg icp_offset_bytes =
          bld.ADD(vertex_offset_bytes, channel_offsets);
    
       /* Use start of ICP handles as the base offset.  There is one register
        * of URB handles per vertex, so inform the register allocator that
        * we might read up to nir->info.gs.vertices_in registers.
        */
       brw_reg icp_handle = bld.vgrf(BRW_TYPE_UD);
       bld.emit(SHADER_OPCODE_MOV_INDIRECT, icp_handle, start,
                icp_offset_bytes,
                brw_imm_ud(brw_tcs_prog_key_input_vertices(tcs_key) *
                           grf_size_bytes));
    
       return icp_handle;
    }
    
    static void
    setup_barrier_message_payload_gfx125(const brw_builder &bld,
                                         const brw_reg &msg_payload)
    {
       const brw_builder ubld = bld.exec_all().group(1, 0);
       const struct intel_device_info *devinfo = bld.shader->devinfo;
       assert(devinfo->verx10 >= 125);
    
       /* From BSpec: 54006, mov r0.2[31:24] into m0.2[31:24] and m0.2[23:16] */
       brw_reg m0_10ub = horiz_offset(retype(msg_payload, BRW_TYPE_UB), 10);
       brw_reg r0_11ub =
          stride(suboffset(retype(brw_vec1_grf(0, 0), BRW_TYPE_UB), 11),
                 0, 1, 0);
       ubld.group(2, 0).MOV(m0_10ub, r0_11ub);
    
       if (devinfo->ver >= 20) {
          /* Use an active threads barrier. */
          const brw_reg m0_2ud = component(retype(msg_payload, BRW_TYPE_UD), 2);
          ubld.OR(m0_2ud, m0_2ud, brw_imm_ud(1u << 8));
       }
    }
    
    static void
    emit_barrier(nir_to_brw_state &ntb)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld;
       const brw_builder ubld = bld.exec_all();
       const brw_builder hbld = ubld.group(8 * reg_unit(devinfo), 0);
       fs_visitor &s = ntb.s;
    
       /* We are getting the barrier ID from the compute shader header */
       assert(gl_shader_stage_uses_workgroup(s.stage));
    
       /* Zero-initialize the payload */
       brw_reg payload = hbld.MOV(brw_imm_ud(0u));
    
       if (devinfo->verx10 >= 125) {
          setup_barrier_message_payload_gfx125(bld, payload);
       } else {
          assert(gl_shader_stage_is_compute(s.stage));
    
          brw_reg barrier_id_mask =
             brw_imm_ud(devinfo->ver == 9 ? 0x8f000000u : 0x7f000000u);
    
          /* Copy the barrier id from r0.2 to the message payload reg.2 */
          brw_reg r0_2 = brw_reg(retype(brw_vec1_grf(0, 2), BRW_TYPE_UD));
          ubld.group(1, 0).AND(component(payload, 2), r0_2, barrier_id_mask);
       }
    
       /* Emit a gateway "barrier" message using the payload we set up, followed
        * by a wait instruction.
        */
       ubld.emit(SHADER_OPCODE_BARRIER, reg_undef, payload);
    }
    
    static void
    emit_tcs_barrier(nir_to_brw_state &ntb)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_TESS_CTRL);
       struct brw_tcs_prog_data *tcs_prog_data = brw_tcs_prog_data(s.prog_data);
    
       brw_reg m0 = bld.vgrf(BRW_TYPE_UD);
       brw_reg m0_2 = component(m0, 2);
    
       const brw_builder chanbld = bld.exec_all().group(1, 0);
    
       /* Zero the message header */
       bld.exec_all().MOV(m0, brw_imm_ud(0u));
    
       if (devinfo->verx10 >= 125) {
          setup_barrier_message_payload_gfx125(bld, m0);
       } else if (devinfo->ver >= 11) {
          chanbld.AND(m0_2, retype(brw_vec1_grf(0, 2), BRW_TYPE_UD),
                      brw_imm_ud(INTEL_MASK(30, 24)));
    
          /* Set the Barrier Count and the enable bit */
          chanbld.OR(m0_2, m0_2,
                     brw_imm_ud(tcs_prog_data->instances << 8 | (1 << 15)));
       } else {
          /* Copy "Barrier ID" from r0.2, bits 16:13 */
          chanbld.AND(m0_2, retype(brw_vec1_grf(0, 2), BRW_TYPE_UD),
                      brw_imm_ud(INTEL_MASK(16, 13)));
    
          /* Shift it up to bits 27:24. */
          chanbld.SHL(m0_2, m0_2, brw_imm_ud(11));
    
          /* Set the Barrier Count and the enable bit */
          chanbld.OR(m0_2, m0_2,
                     brw_imm_ud(tcs_prog_data->instances << 9 | (1 << 15)));
       }
    
       bld.emit(SHADER_OPCODE_BARRIER, bld.null_reg_ud(), m0);
    }
    
    static void
    fs_nir_emit_tcs_intrinsic(nir_to_brw_state &ntb,
                              nir_intrinsic_instr *instr)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_TESS_CTRL);
       struct brw_tcs_prog_data *tcs_prog_data = brw_tcs_prog_data(s.prog_data);
       struct brw_vue_prog_data *vue_prog_data = &tcs_prog_data->base;
    
       brw_reg dst;
       if (nir_intrinsic_infos[instr->intrinsic].has_dest)
          dst = get_nir_def(ntb, instr->def);
    
       switch (instr->intrinsic) {
       case nir_intrinsic_load_primitive_id:
          bld.MOV(dst, s.tcs_payload().primitive_id);
          break;
       case nir_intrinsic_load_invocation_id:
          bld.MOV(retype(dst, s.invocation_id.type), s.invocation_id);
          break;
    
       case nir_intrinsic_barrier:
          if (nir_intrinsic_memory_scope(instr) != SCOPE_NONE)
             fs_nir_emit_intrinsic(ntb, bld, instr);
          if (nir_intrinsic_execution_scope(instr) == SCOPE_WORKGROUP) {
             if (tcs_prog_data->instances != 1)
                emit_tcs_barrier(ntb);
          }
          break;
    
       case nir_intrinsic_load_input:
          unreachable("nir_lower_io should never give us these.");
          break;
    
       case nir_intrinsic_load_per_vertex_input: {
          assert(instr->def.bit_size == 32);
          brw_reg indirect_offset = get_indirect_offset(ntb, instr);
          unsigned imm_offset = nir_intrinsic_base(instr);
          fs_inst *inst;
    
          const bool multi_patch =
             vue_prog_data->dispatch_mode == INTEL_DISPATCH_MODE_TCS_MULTI_PATCH;
    
          brw_reg icp_handle = multi_patch ?
             get_tcs_multi_patch_icp_handle(ntb, bld, instr) :
             get_tcs_single_patch_icp_handle(ntb, bld, instr);
    
          /* We can only read two double components with each URB read, so
           * we send two read messages in that case, each one loading up to
           * two double components.
           */
          unsigned num_components = instr->num_components;
          unsigned first_component = nir_intrinsic_component(instr);
    
          brw_reg srcs[URB_LOGICAL_NUM_SRCS];
          srcs[URB_LOGICAL_SRC_HANDLE] = icp_handle;
    
          if (indirect_offset.file == BAD_FILE) {
             /* Constant indexing - use global offset. */
             if (first_component != 0) {
                unsigned read_components = num_components + first_component;
                brw_reg tmp = bld.vgrf(dst.type, read_components);
                inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, tmp, srcs,
                                ARRAY_SIZE(srcs));
                brw_combine_with_vec(bld, dst, offset(tmp, bld, first_component),
                                     num_components);
             } else {
                inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, dst, srcs,
                                ARRAY_SIZE(srcs));
             }
             inst->offset = imm_offset;
          } else {
             /* Indirect indexing - use per-slot offsets as well. */
             srcs[URB_LOGICAL_SRC_PER_SLOT_OFFSETS] = indirect_offset;
    
             if (first_component != 0) {
                unsigned read_components = num_components + first_component;
                brw_reg tmp = bld.vgrf(dst.type, read_components);
                inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, tmp,
                                srcs, ARRAY_SIZE(srcs));
                brw_combine_with_vec(bld, dst, offset(tmp, bld, first_component),
                                     num_components);
             } else {
                inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, dst,
                                srcs, ARRAY_SIZE(srcs));
             }
             inst->offset = imm_offset;
          }
          inst->size_written = (num_components + first_component) *
                               inst->dst.component_size(inst->exec_size);
    
          /* Copy the temporary to the destination to deal with writemasking.
           *
           * Also attempt to deal with gl_PointSize being in the .w component.
           */
          if (inst->offset == 0 && indirect_offset.file == BAD_FILE) {
             assert(brw_type_size_bytes(dst.type) == 4);
             inst->dst = bld.vgrf(dst.type, 4);
             inst->size_written = 4 * REG_SIZE * reg_unit(devinfo);
             bld.MOV(dst, offset(inst->dst, bld, 3));
          }
          break;
       }
    
       case nir_intrinsic_load_output:
       case nir_intrinsic_load_per_vertex_output: {
          assert(instr->def.bit_size == 32);
          brw_reg indirect_offset = get_indirect_offset(ntb, instr);
          unsigned imm_offset = nir_intrinsic_base(instr);
          unsigned first_component = nir_intrinsic_component(instr);
    
          fs_inst *inst;
          if (indirect_offset.file == BAD_FILE) {
             /* This MOV replicates the output handle to all enabled channels
              * is SINGLE_PATCH mode.
              */
             brw_reg patch_handle = bld.MOV(s.tcs_payload().patch_urb_output);
    
             {
                brw_reg srcs[URB_LOGICAL_NUM_SRCS];
                srcs[URB_LOGICAL_SRC_HANDLE] = patch_handle;
    
                if (first_component != 0) {
                   unsigned read_components =
                      instr->num_components + first_component;
                   brw_reg tmp = bld.vgrf(dst.type, read_components);
                   inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, tmp,
                                   srcs, ARRAY_SIZE(srcs));
                   inst->size_written = read_components * REG_SIZE * reg_unit(devinfo);
                   brw_combine_with_vec(bld, dst, offset(tmp, bld, first_component),
                                        instr->num_components);
                } else {
                   inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, dst,
                                   srcs, ARRAY_SIZE(srcs));
                   inst->size_written = instr->num_components * REG_SIZE * reg_unit(devinfo);
                }
                inst->offset = imm_offset;
             }
          } else {
             /* Indirect indexing - use per-slot offsets as well. */
             brw_reg srcs[URB_LOGICAL_NUM_SRCS];
             srcs[URB_LOGICAL_SRC_HANDLE] = s.tcs_payload().patch_urb_output;
             srcs[URB_LOGICAL_SRC_PER_SLOT_OFFSETS] = indirect_offset;
    
             if (first_component != 0) {
                unsigned read_components =
                   instr->num_components + first_component;
                brw_reg tmp = bld.vgrf(dst.type, read_components);
                inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, tmp,
                                srcs, ARRAY_SIZE(srcs));
                inst->size_written = read_components * REG_SIZE * reg_unit(devinfo);
                brw_combine_with_vec(bld, dst, offset(tmp, bld, first_component),
                                     instr->num_components);
             } else {
                inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, dst,
                                srcs, ARRAY_SIZE(srcs));
                inst->size_written = instr->num_components * REG_SIZE * reg_unit(devinfo);
             }
             inst->offset = imm_offset;
          }
          break;
       }
    
       case nir_intrinsic_store_output:
       case nir_intrinsic_store_per_vertex_output: {
          assert(nir_src_bit_size(instr->src[0]) == 32);
          brw_reg value = get_nir_src(ntb, instr->src[0], -1);
          brw_reg indirect_offset = get_indirect_offset(ntb, instr);
          unsigned imm_offset = nir_intrinsic_base(instr);
          unsigned mask = nir_intrinsic_write_mask(instr);
    
          if (mask == 0)
             break;
    
          unsigned num_components = util_last_bit(mask);
          unsigned first_component = nir_intrinsic_component(instr);
          assert((first_component + num_components) <= 4);
    
          mask = mask << first_component;
    
          const bool has_urb_lsc = devinfo->ver >= 20;
    
          brw_reg mask_reg;
          if (mask != WRITEMASK_XYZW)
             mask_reg = brw_imm_ud(mask << 16);
    
          brw_reg sources[4];
    
          unsigned m = has_urb_lsc ? 0 : first_component;
          for (unsigned i = 0; i < num_components; i++) {
             int c = i + first_component;
             if (mask & (1 << c)) {
                sources[m++] = offset(value, bld, i);
             } else if (devinfo->ver < 20) {
                m++;
             }
          }
    
          assert(has_urb_lsc || m == (first_component + num_components));
    
          brw_reg srcs[URB_LOGICAL_NUM_SRCS];
          srcs[URB_LOGICAL_SRC_HANDLE] = s.tcs_payload().patch_urb_output;
          srcs[URB_LOGICAL_SRC_PER_SLOT_OFFSETS] = indirect_offset;
          srcs[URB_LOGICAL_SRC_CHANNEL_MASK] = mask_reg;
          srcs[URB_LOGICAL_SRC_DATA] = bld.vgrf(BRW_TYPE_F, m);
          srcs[URB_LOGICAL_SRC_COMPONENTS] = brw_imm_ud(m);
          bld.LOAD_PAYLOAD(srcs[URB_LOGICAL_SRC_DATA], sources, m, 0);
    
          fs_inst *inst = bld.emit(SHADER_OPCODE_URB_WRITE_LOGICAL, reg_undef,
                                   srcs, ARRAY_SIZE(srcs));
          inst->offset = imm_offset;
          break;
       }
    
       default:
          fs_nir_emit_intrinsic(ntb, bld, instr);
          break;
       }
    }
    
    static void
    fs_nir_emit_tes_intrinsic(nir_to_brw_state &ntb,
                              nir_intrinsic_instr *instr)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_TESS_EVAL);
       struct brw_tes_prog_data *tes_prog_data = brw_tes_prog_data(s.prog_data);
    
       brw_reg dest;
       if (nir_intrinsic_infos[instr->intrinsic].has_dest)
          dest = get_nir_def(ntb, instr->def);
    
       switch (instr->intrinsic) {
       case nir_intrinsic_load_primitive_id:
          bld.MOV(dest, s.tes_payload().primitive_id);
          break;
    
       case nir_intrinsic_load_tess_coord:
          for (unsigned i = 0; i < 3; i++)
             bld.MOV(offset(dest, bld, i), s.tes_payload().coords[i]);
          break;
    
       case nir_intrinsic_load_input:
       case nir_intrinsic_load_per_vertex_input: {
          assert(instr->def.bit_size == 32);
          brw_reg indirect_offset = get_indirect_offset(ntb, instr);
          unsigned imm_offset = nir_intrinsic_base(instr);
          unsigned first_component = nir_intrinsic_component(instr);
    
          fs_inst *inst;
          if (indirect_offset.file == BAD_FILE) {
             /* Arbitrarily only push up to 32 vec4 slots worth of data,
              * which is 16 registers (since each holds 2 vec4 slots).
              */
             const unsigned max_push_slots = 32;
             if (imm_offset < max_push_slots) {
                const brw_reg src = horiz_offset(brw_attr_reg(0, dest.type),
                                                4 * imm_offset + first_component);
                brw_reg comps[NIR_MAX_VEC_COMPONENTS];
                for (unsigned i = 0; i < instr->num_components; i++) {
                   comps[i] = component(src, i);
                }
                bld.VEC(dest, comps, instr->num_components);
    
                tes_prog_data->base.urb_read_length =
                   MAX2(tes_prog_data->base.urb_read_length,
                        (imm_offset / 2) + 1);
             } else {
                /* Replicate the patch handle to all enabled channels */
                brw_reg srcs[URB_LOGICAL_NUM_SRCS];
                srcs[URB_LOGICAL_SRC_HANDLE] = s.tes_payload().patch_urb_input;
    
                if (first_component != 0) {
                   unsigned read_components =
                      instr->num_components + first_component;
                   brw_reg tmp = bld.vgrf(dest.type, read_components);
                   inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, tmp,
                                   srcs, ARRAY_SIZE(srcs));
                   inst->size_written = read_components * REG_SIZE * reg_unit(devinfo);
                   brw_combine_with_vec(bld, dest, offset(tmp, bld, first_component),
                                        instr->num_components);
                } else {
                   inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, dest,
                                   srcs, ARRAY_SIZE(srcs));
                   inst->size_written = instr->num_components * REG_SIZE * reg_unit(devinfo);
                }
                inst->offset = imm_offset;
             }
          } else {
             /* Indirect indexing - use per-slot offsets as well. */
    
             /* We can only read two double components with each URB read, so
              * we send two read messages in that case, each one loading up to
              * two double components.
              */
             unsigned num_components = instr->num_components;
    
             brw_reg srcs[URB_LOGICAL_NUM_SRCS];
             srcs[URB_LOGICAL_SRC_HANDLE] = s.tes_payload().patch_urb_input;
             srcs[URB_LOGICAL_SRC_PER_SLOT_OFFSETS] = indirect_offset;
    
             if (first_component != 0) {
                unsigned read_components =
                    num_components + first_component;
                brw_reg tmp = bld.vgrf(dest.type, read_components);
                inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, tmp,
                                srcs, ARRAY_SIZE(srcs));
                brw_combine_with_vec(bld, dest, offset(tmp, bld, first_component),
                                     num_components);
             } else {
                inst = bld.emit(SHADER_OPCODE_URB_READ_LOGICAL, dest,
                                srcs, ARRAY_SIZE(srcs));
             }
             inst->offset = imm_offset;
             inst->size_written = (num_components + first_component) *
                                  inst->dst.component_size(inst->exec_size);
          }
          break;
       }
       default:
          fs_nir_emit_intrinsic(ntb, bld, instr);
          break;
       }
    }
    
    static void
    fs_nir_emit_gs_intrinsic(nir_to_brw_state &ntb,
                             nir_intrinsic_instr *instr)
    {
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_GEOMETRY);
    
       brw_reg dest;
       if (nir_intrinsic_infos[instr->intrinsic].has_dest)
          dest = get_nir_def(ntb, instr->def);
    
       switch (instr->intrinsic) {
       case nir_intrinsic_load_primitive_id:
          assert(s.stage == MESA_SHADER_GEOMETRY);
          assert(brw_gs_prog_data(s.prog_data)->include_primitive_id);
          bld.MOV(retype(dest, BRW_TYPE_UD), s.gs_payload().primitive_id);
          break;
    
       case nir_intrinsic_load_input:
          unreachable("load_input intrinsics are invalid for the GS stage");
    
       case nir_intrinsic_load_per_vertex_input:
          emit_gs_input_load(ntb, dest, instr->src[0], nir_intrinsic_base(instr),
                             instr->src[1], instr->num_components,
                             nir_intrinsic_component(instr));
          break;
    
       case nir_intrinsic_emit_vertex_with_counter:
          emit_gs_vertex(ntb, instr->src[0], nir_intrinsic_stream_id(instr));
    
          /* After an EmitVertex() call, the values of all outputs are undefined.
           * If this is not in control flow, recreate a fresh set of output
           * registers to keep their live ranges separate.
           */
          if (instr->instr.block->cf_node.parent->type == nir_cf_node_function)
             fs_nir_setup_outputs(ntb);
          break;
    
       case nir_intrinsic_end_primitive_with_counter:
          emit_gs_end_primitive(ntb, instr->src[0]);
          break;
    
       case nir_intrinsic_set_vertex_and_primitive_count:
          bld.MOV(s.final_gs_vertex_count, get_nir_src(ntb, instr->src[0]));
          break;
    
       case nir_intrinsic_load_invocation_id: {
          brw_reg val = ntb.system_values[SYSTEM_VALUE_INVOCATION_ID];
          assert(val.file != BAD_FILE);
          dest.type = val.type;
          bld.MOV(dest, val);
          break;
       }
    
       default:
          fs_nir_emit_intrinsic(ntb, bld, instr);
          break;
       }
    }
    
    /**
     * Fetch the current render target layer index.
     */
    static brw_reg
    fetch_render_target_array_index(const brw_builder &bld)
    {
       const fs_visitor *v = bld.shader;
    
       if (bld.shader->devinfo->ver >= 20) {
          /* Gfx20+ has separate Render Target Array indices for each pair
           * of subspans in order to support multiple polygons, so we need
           * to use a <1;8,0> region in order to select the correct word
           * for each channel.
           */
          const brw_reg idx = bld.vgrf(BRW_TYPE_UD);
    
          for (unsigned i = 0; i < DIV_ROUND_UP(bld.dispatch_width(), 16); i++) {
             const brw_builder hbld = bld.group(16, i);
             const struct brw_reg reg = retype(brw_vec1_grf(2 * i + 1, 1),
                                               BRW_TYPE_UW);
             hbld.AND(offset(idx, hbld, i), stride(reg, 1, 8, 0),
                      brw_imm_uw(0x7ff));
          }
    
          return idx;
       } else if (bld.shader->devinfo->ver >= 12 && v->max_polygons == 2) {
          /* According to the BSpec "PS Thread Payload for Normal
           * Dispatch", the render target array index is stored as bits
           * 26:16 of either the R1.1 or R1.6 poly info dwords, for the
           * first and second polygons respectively in multipolygon PS
           * dispatch mode.
           */
          assert(bld.dispatch_width() == 16);
          const brw_reg idx = bld.vgrf(BRW_TYPE_UD);
    
          for (unsigned i = 0; i < v->max_polygons; i++) {
             const brw_builder hbld = bld.group(8, i);
             const struct brw_reg g1 = brw_uw1_reg(FIXED_GRF, 1, 3 + 10 * i);
             hbld.AND(offset(idx, hbld, i), g1, brw_imm_uw(0x7ff));
          }
    
          return idx;
       } else if (bld.shader->devinfo->ver >= 12) {
          /* The render target array index is provided in the thread payload as
           * bits 26:16 of r1.1.
           */
          const brw_reg idx = bld.vgrf(BRW_TYPE_UD);
          bld.AND(idx, brw_uw1_reg(FIXED_GRF, 1, 3),
                  brw_imm_uw(0x7ff));
          return idx;
       } else {
          /* The render target array index is provided in the thread payload as
           * bits 26:16 of r0.0.
           */
          const brw_reg idx = bld.vgrf(BRW_TYPE_UD);
          bld.AND(idx, brw_uw1_reg(FIXED_GRF, 0, 1),
                  brw_imm_uw(0x7ff));
          return idx;
       }
    }
    
    static brw_reg
    fetch_viewport_index(const brw_builder &bld)
    {
       const fs_visitor *v = bld.shader;
    
       if (bld.shader->devinfo->ver >= 20) {
          /* Gfx20+ has separate viewport indices for each pair
           * of subspans in order to support multiple polygons, so we need
           * to use a <1;8,0> region in order to select the correct word
           * for each channel.
           */
          const brw_reg idx = bld.vgrf(BRW_TYPE_UD);
    
          for (unsigned i = 0; i < DIV_ROUND_UP(bld.dispatch_width(), 16); i++) {
             const brw_builder hbld = bld.group(16, i);
             const struct brw_reg reg = retype(xe2_vec1_grf(i, 9),
                                               BRW_TYPE_UW);
             hbld.AND(offset(idx, hbld, i), stride(reg, 1, 8, 0),
                      brw_imm_uw(0xf000));
          }
    
          bld.SHR(idx, idx, brw_imm_ud(12));
          return idx;
       } else if (bld.shader->devinfo->ver >= 12 && v->max_polygons == 2) {
          /* According to the BSpec "PS Thread Payload for Normal
           * Dispatch", the viewport index is stored as bits
           * 30:27 of either the R1.1 or R1.6 poly info dwords, for the
           * first and second polygons respectively in multipolygon PS
           * dispatch mode.
           */
          assert(bld.dispatch_width() == 16);
          const brw_reg idx = bld.vgrf(BRW_TYPE_UD);
          brw_reg vp_idx_per_poly_dw[2] = {
             brw_ud1_reg(FIXED_GRF, 1, 1), /* R1.1 bits 30:27 */
             brw_ud1_reg(FIXED_GRF, 1, 6), /* R1.6 bits 30:27 */
          };
    
          for (unsigned i = 0; i < v->max_polygons; i++) {
             const brw_builder hbld = bld.group(8, i);
             hbld.SHR(offset(idx, hbld, i), vp_idx_per_poly_dw[i], brw_imm_ud(27));
          }
    
          return bld.AND(idx, brw_imm_ud(0xf));
       } else if (bld.shader->devinfo->ver >= 12) {
          /* The viewport index is provided in the thread payload as
           * bits 30:27 of r1.1.
           */
          const brw_reg idx = bld.vgrf(BRW_TYPE_UD);
          bld.SHR(idx,
                  bld.AND(brw_uw1_reg(FIXED_GRF, 1, 3),
                          brw_imm_uw(0x7800)),
                  brw_imm_ud(11));
          return idx;
       } else {
          /* The viewport index is provided in the thread payload as
           * bits 30:27 of r0.0.
           */
          const brw_reg idx = bld.vgrf(BRW_TYPE_UD);
          bld.SHR(idx,
                  bld.AND(brw_uw1_reg(FIXED_GRF, 0, 1),
                          brw_imm_uw(0x7800)),
                  brw_imm_ud(11));
          return idx;
       }
    }
    
    /* Sample from the MCS surface attached to this multisample texture. */
    static brw_reg
    emit_mcs_fetch(nir_to_brw_state &ntb, const brw_reg &coordinate, unsigned components,
                   const brw_reg &texture,
                   const brw_reg &texture_handle)
    {
       const brw_builder &bld = ntb.bld;
    
       const brw_reg dest = bld.vgrf(BRW_TYPE_UD, 4);
    
       brw_reg srcs[TEX_LOGICAL_NUM_SRCS];
       srcs[TEX_LOGICAL_SRC_COORDINATE] = coordinate;
       srcs[TEX_LOGICAL_SRC_SURFACE] = texture;
       srcs[TEX_LOGICAL_SRC_SAMPLER] = brw_imm_ud(0);
       srcs[TEX_LOGICAL_SRC_SURFACE_HANDLE] = texture_handle;
       srcs[TEX_LOGICAL_SRC_COORD_COMPONENTS] = brw_imm_d(components);
       srcs[TEX_LOGICAL_SRC_GRAD_COMPONENTS] = brw_imm_d(0);
       srcs[TEX_LOGICAL_SRC_RESIDENCY] = brw_imm_d(0);
    
       fs_inst *inst = bld.emit(SHADER_OPCODE_TXF_MCS_LOGICAL, dest, srcs,
                                ARRAY_SIZE(srcs));
    
       /* We only care about one or two regs of response, but the sampler always
        * writes 4/8.
        */
       inst->size_written = 4 * dest.component_size(inst->exec_size);
    
       return dest;
    }
    
    /**
     * Fake non-coherent framebuffer read implemented using TXF to fetch from the
     * framebuffer at the current fragment coordinates and sample index.
     */
    static fs_inst *
    emit_non_coherent_fb_read(nir_to_brw_state &ntb, const brw_builder &bld, const brw_reg &dst,
                              unsigned target)
    {
       fs_visitor &s = ntb.s;
       const struct intel_device_info *devinfo = s.devinfo;
    
       assert(bld.shader->stage == MESA_SHADER_FRAGMENT);
       const brw_wm_prog_key *wm_key =
          reinterpret_cast<const brw_wm_prog_key *>(s.key);
       assert(!wm_key->coherent_fb_fetch);
    
       /* Calculate the fragment coordinates. */
       const brw_reg coords = bld.vgrf(BRW_TYPE_UD, 3);
       bld.MOV(offset(coords, bld, 0), s.pixel_x);
       bld.MOV(offset(coords, bld, 1), s.pixel_y);
       bld.MOV(offset(coords, bld, 2), fetch_render_target_array_index(bld));
    
       /* Calculate the sample index and MCS payload when multisampling.  Luckily
        * the MCS fetch message behaves deterministically for UMS surfaces, so it
        * shouldn't be necessary to recompile based on whether the framebuffer is
        * CMS or UMS.
        */
       assert(wm_key->multisample_fbo == INTEL_ALWAYS ||
              wm_key->multisample_fbo == INTEL_NEVER);
       if (wm_key->multisample_fbo &&
           ntb.system_values[SYSTEM_VALUE_SAMPLE_ID].file == BAD_FILE)
          ntb.system_values[SYSTEM_VALUE_SAMPLE_ID] = emit_sampleid_setup(ntb);
    
       const brw_reg sample = ntb.system_values[SYSTEM_VALUE_SAMPLE_ID];
       const brw_reg mcs = wm_key->multisample_fbo ?
          emit_mcs_fetch(ntb, coords, 3, brw_imm_ud(target), brw_reg()) : brw_reg();
    
       /* Use either a normal or a CMS texel fetch message depending on whether
        * the framebuffer is single or multisample.  On SKL+ use the wide CMS
        * message just in case the framebuffer uses 16x multisampling, it should
        * be equivalent to the normal CMS fetch for lower multisampling modes.
        */
       opcode op;
       if (wm_key->multisample_fbo) {
          /* On SKL+ use the wide CMS message just in case the framebuffer uses 16x
           * multisampling, it should be equivalent to the normal CMS fetch for
           * lower multisampling modes.
           *
           * On Gfx12HP, there is only CMS_W variant available.
           */
          if (devinfo->verx10 >= 125)
             op = SHADER_OPCODE_TXF_CMS_W_GFX12_LOGICAL;
          else
             op = SHADER_OPCODE_TXF_CMS_W_LOGICAL;
       } else {
          op = SHADER_OPCODE_TXF_LOGICAL;
       }
    
       /* Emit the instruction. */
       brw_reg srcs[TEX_LOGICAL_NUM_SRCS];
       srcs[TEX_LOGICAL_SRC_COORDINATE]       = coords;
       srcs[TEX_LOGICAL_SRC_LOD]              = brw_imm_ud(0);
       srcs[TEX_LOGICAL_SRC_SAMPLE_INDEX]     = sample;
       srcs[TEX_LOGICAL_SRC_MCS]              = mcs;
       srcs[TEX_LOGICAL_SRC_SURFACE]          = brw_imm_ud(target);
       srcs[TEX_LOGICAL_SRC_SAMPLER]          = brw_imm_ud(0);
       srcs[TEX_LOGICAL_SRC_COORD_COMPONENTS] = brw_imm_ud(3);
       srcs[TEX_LOGICAL_SRC_GRAD_COMPONENTS]  = brw_imm_ud(0);
       srcs[TEX_LOGICAL_SRC_RESIDENCY]        = brw_imm_ud(0);
    
       fs_inst *inst = bld.emit(op, dst, srcs, ARRAY_SIZE(srcs));
       inst->size_written = 4 * inst->dst.component_size(inst->exec_size);
    
       return inst;
    }
    
    /**
     * Actual coherent framebuffer read implemented using the native render target
     * read message.  Requires SKL+.
     */
    static fs_inst *
    emit_coherent_fb_read(const brw_builder &bld, const brw_reg &dst, unsigned target)
    {
       fs_inst *inst = bld.emit(FS_OPCODE_FB_READ_LOGICAL, dst);
       inst->target = target;
       inst->size_written = 4 * inst->dst.component_size(inst->exec_size);
    
       return inst;
    }
    
    static brw_reg
    alloc_temporary(const brw_builder &bld, unsigned size, brw_reg *regs, unsigned n)
    {
       if (n && regs[0].file != BAD_FILE) {
          return regs[0];
    
       } else {
          const brw_reg tmp = bld.vgrf(BRW_TYPE_F, size);
    
          for (unsigned i = 0; i < n; i++)
             regs[i] = tmp;
    
          return tmp;
       }
    }
    
    static brw_reg
    alloc_frag_output(nir_to_brw_state &ntb, unsigned location)
    {
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_FRAGMENT);
       const brw_wm_prog_key *const key =
          reinterpret_cast<const brw_wm_prog_key *>(s.key);
       const unsigned l = GET_FIELD(location, BRW_NIR_FRAG_OUTPUT_LOCATION);
       const unsigned i = GET_FIELD(location, BRW_NIR_FRAG_OUTPUT_INDEX);
    
       if (i > 0 || (key->force_dual_color_blend && l == FRAG_RESULT_DATA1))
          return alloc_temporary(ntb.bld, 4, &s.dual_src_output, 1);
    
       else if (l == FRAG_RESULT_COLOR)
          return alloc_temporary(ntb.bld, 4, s.outputs,
                                 MAX2(key->nr_color_regions, 1));
    
       else if (l == FRAG_RESULT_DEPTH)
          return alloc_temporary(ntb.bld, 1, &s.frag_depth, 1);
    
       else if (l == FRAG_RESULT_STENCIL)
          return alloc_temporary(ntb.bld, 1, &s.frag_stencil, 1);
    
       else if (l == FRAG_RESULT_SAMPLE_MASK)
          return alloc_temporary(ntb.bld, 1, &s.sample_mask, 1);
    
       else if (l >= FRAG_RESULT_DATA0 &&
                l < FRAG_RESULT_DATA0 + BRW_MAX_DRAW_BUFFERS)
          return alloc_temporary(ntb.bld, 4,
                                 &s.outputs[l - FRAG_RESULT_DATA0], 1);
    
       else
          unreachable("Invalid location");
    }
    
    static void
    emit_is_helper_invocation(nir_to_brw_state &ntb, brw_reg result)
    {
       const brw_builder &bld = ntb.bld;
    
       /* Unlike the regular gl_HelperInvocation, that is defined at dispatch,
        * the helperInvocationEXT() (aka SpvOpIsHelperInvocationEXT) takes into
        * consideration demoted invocations.
        */
       result.type = BRW_TYPE_UD;
    
       bld.MOV(result, brw_imm_ud(0));
    
       /* See brw_sample_mask_reg() for why we split SIMD32 into SIMD16 here. */
       unsigned width = bld.dispatch_width();
       for (unsigned i = 0; i < DIV_ROUND_UP(width, 16); i++) {
          const brw_builder b = bld.group(MIN2(width, 16), i);
    
          fs_inst *mov = b.MOV(offset(result, b, i), brw_imm_ud(~0));
    
          /* The at() ensures that any code emitted to get the predicate happens
           * before the mov right above.  This is not an issue elsewhere because
           * lowering code already set up the builder this way.
           */
          brw_emit_predicate_on_sample_mask(b.at(NULL, mov), mov);
          mov->predicate_inverse = true;
       }
    }
    
    static brw_reg
    emit_frontfacing_interpolation(nir_to_brw_state &ntb)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       brw_reg ff = bld.vgrf(BRW_TYPE_D);
    
       if (devinfo->ver >= 20) {
          /* Gfx20+ has separate back-facing bits for each pair of
           * subspans in order to support multiple polygons, so we need to
           * use a <1;8,0> region in order to select the correct word for
           * each channel.
           */
          const brw_reg tmp = bld.vgrf(BRW_TYPE_UW);
    
          for (unsigned i = 0; i < DIV_ROUND_UP(s.dispatch_width, 16); i++) {
             const brw_builder hbld = bld.group(16, i);
             const struct brw_reg gi_uw = retype(xe2_vec1_grf(i, 9),
                                                 BRW_TYPE_UW);
             hbld.AND(offset(tmp, hbld, i), gi_uw, brw_imm_uw(0x800));
          }
    
          bld.CMP(ff, tmp, brw_imm_uw(0), BRW_CONDITIONAL_Z);
    
       } else if (devinfo->ver >= 12 && s.max_polygons == 2) {
          /* According to the BSpec "PS Thread Payload for Normal
           * Dispatch", the front/back facing interpolation bit is stored
           * as bit 15 of either the R1.1 or R1.6 poly info field, for the
           * first and second polygons respectively in multipolygon PS
           * dispatch mode.
           */
          assert(s.dispatch_width == 16);
          brw_reg tmp = bld.vgrf(BRW_TYPE_W);
    
          for (unsigned i = 0; i < s.max_polygons; i++) {
             const brw_builder hbld = bld.group(8, i);
             const struct brw_reg g1 = retype(brw_vec1_grf(1, 1 + 5 * i),
                                              BRW_TYPE_W);
             hbld.ASR(offset(tmp, hbld, i), g1, brw_imm_d(15));
          }
    
          bld.NOT(ff, tmp);
    
       } else if (devinfo->ver >= 12) {
          brw_reg g1 = brw_reg(retype(brw_vec1_grf(1, 1), BRW_TYPE_W));
    
          brw_reg tmp = bld.vgrf(BRW_TYPE_W);
          bld.ASR(tmp, g1, brw_imm_d(15));
          bld.NOT(ff, tmp);
       } else {
          /* Bit 15 of g0.0 is 0 if the polygon is front facing. We want to create
           * a boolean result from this (~0/true or 0/false).
           *
           * We can use the fact that bit 15 is the MSB of g0.0:W to accomplish
           * this task in only one instruction:
           *    - a negation source modifier will flip the bit; and
           *    - a W -> D type conversion will sign extend the bit into the high
           *      word of the destination.
           *
           * An ASR 15 fills the low word of the destination.
           */
          brw_reg g0 = brw_reg(retype(brw_vec1_grf(0, 0), BRW_TYPE_W));
    
          bld.ASR(ff, negate(g0), brw_imm_d(15));
       }
    
       return ff;
    }
    
    static brw_reg
    emit_samplepos_setup(nir_to_brw_state &ntb)
    {
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_FRAGMENT);
       struct brw_wm_prog_data *wm_prog_data = brw_wm_prog_data(s.prog_data);
    
       const brw_builder abld = bld.annotate("compute sample position");
       brw_reg pos = abld.vgrf(BRW_TYPE_F, 2);
    
       if (wm_prog_data->persample_dispatch == INTEL_NEVER) {
          /* From ARB_sample_shading specification:
           * "When rendering to a non-multisample buffer, or if multisample
           *  rasterization is disabled, gl_SamplePosition will always be
           *  (0.5, 0.5).
           */
          bld.MOV(offset(pos, bld, 0), brw_imm_f(0.5f));
          bld.MOV(offset(pos, bld, 1), brw_imm_f(0.5f));
          return pos;
       }
    
       /* WM will be run in MSDISPMODE_PERSAMPLE. So, only one of SIMD8 or SIMD16
        * mode will be enabled.
        *
        * From the Ivy Bridge PRM, volume 2 part 1, page 344:
        * R31.1:0         Position Offset X/Y for Slot[3:0]
        * R31.3:2         Position Offset X/Y for Slot[7:4]
        * .....
        *
        * The X, Y sample positions come in as bytes in  thread payload. So, read
        * the positions using vstride=16, width=8, hstride=2.
        */
       const brw_reg sample_pos_reg =
          brw_fetch_payload_reg(abld, s.fs_payload().sample_pos_reg, BRW_TYPE_W);
    
       for (unsigned i = 0; i < 2; i++) {
          brw_reg tmp_d = bld.vgrf(BRW_TYPE_D);
          abld.MOV(tmp_d, subscript(sample_pos_reg, BRW_TYPE_B, i));
          /* Convert int_sample_pos to floating point */
          brw_reg tmp_f = bld.vgrf(BRW_TYPE_F);
          abld.MOV(tmp_f, tmp_d);
          /* Scale to the range [0, 1] */
          abld.MUL(offset(pos, abld, i), tmp_f, brw_imm_f(1 / 16.0f));
       }
    
       if (wm_prog_data->persample_dispatch == INTEL_SOMETIMES) {
          brw_check_dynamic_msaa_flag(abld, wm_prog_data,
                                      INTEL_MSAA_FLAG_PERSAMPLE_DISPATCH);
          for (unsigned i = 0; i < 2; i++) {
             set_predicate(BRW_PREDICATE_NORMAL,
                           bld.SEL(offset(pos, abld, i), offset(pos, abld, i),
                                   brw_imm_f(0.5f)));
          }
       }
    
       return pos;
    }
    
    static brw_reg
    emit_sampleid_setup(nir_to_brw_state &ntb)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_FRAGMENT);
       ASSERTED brw_wm_prog_key *key = (brw_wm_prog_key*) s.key;
       struct brw_wm_prog_data *wm_prog_data = brw_wm_prog_data(s.prog_data);
    
       const brw_builder abld = bld.annotate("compute sample id");
       brw_reg sample_id = abld.vgrf(BRW_TYPE_UD);
    
       assert(key->multisample_fbo != INTEL_NEVER);
    
       /* Sample ID comes in as 4-bit numbers in g1.0:
        *
        *    15:12 Slot 3 SampleID (only used in SIMD16)
        *     11:8 Slot 2 SampleID (only used in SIMD16)
        *      7:4 Slot 1 SampleID
        *      3:0 Slot 0 SampleID
        *
        * Each slot corresponds to four channels, so we want to replicate each
        * half-byte value to 4 channels in a row:
        *
        *    dst+0:    .7    .6    .5    .4    .3    .2    .1    .0
        *             7:4   7:4   7:4   7:4   3:0   3:0   3:0   3:0
        *
        *    dst+1:    .7    .6    .5    .4    .3    .2    .1    .0  (if SIMD16)
        *           15:12 15:12 15:12 15:12  11:8  11:8  11:8  11:8
        *
        * First, we read g1.0 with a <1,8,0>UB region, causing the first 8
        * channels to read the first byte (7:0), and the second group of 8
        * channels to read the second byte (15:8).  Then, we shift right by
        * a vector immediate of <4, 4, 4, 4, 0, 0, 0, 0>, moving the slot 1 / 3
        * values into place.  Finally, we AND with 0xf to keep the low nibble.
        *
        *    shr(16) tmp<1>W g1.0<1,8,0>B 0x44440000:V
        *    and(16) dst<1>D tmp<8,8,1>W  0xf:W
        *
        * TODO: These payload bits exist on Gfx7 too, but they appear to always
        *       be zero, so this code fails to work.  We should find out why.
        */
       const brw_reg tmp = abld.vgrf(BRW_TYPE_UW);
    
       for (unsigned i = 0; i < DIV_ROUND_UP(s.dispatch_width, 16); i++) {
          const brw_builder hbld = abld.group(MIN2(16, s.dispatch_width), i);
          /* According to the "PS Thread Payload for Normal Dispatch"
           * pages on the BSpec, the sample ids are stored in R0.8/R1.8
           * on gfx20+ and in R1.0/R2.0 on gfx8+.
           */
          const struct brw_reg id_reg = devinfo->ver >= 20 ? xe2_vec1_grf(i, 8) :
                                        brw_vec1_grf(i + 1, 0);
          hbld.SHR(offset(tmp, hbld, i),
                   stride(retype(id_reg, BRW_TYPE_UB), 1, 8, 0),
                   brw_imm_v(0x44440000));
       }
    
       abld.AND(sample_id, tmp, brw_imm_w(0xf));
    
       if (key->multisample_fbo == INTEL_SOMETIMES) {
          brw_check_dynamic_msaa_flag(abld, wm_prog_data,
                                      INTEL_MSAA_FLAG_MULTISAMPLE_FBO);
          set_predicate(BRW_PREDICATE_NORMAL,
                        abld.SEL(sample_id, sample_id, brw_imm_ud(0)));
       }
    
       return sample_id;
    }
    
    static brw_reg
    emit_samplemaskin_setup(nir_to_brw_state &ntb)
    {
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_FRAGMENT);
       struct brw_wm_prog_data *wm_prog_data = brw_wm_prog_data(s.prog_data);
    
       /* The HW doesn't provide us with expected values. */
       assert(wm_prog_data->coarse_pixel_dispatch != INTEL_ALWAYS);
    
       brw_reg coverage_mask =
          brw_fetch_payload_reg(bld, s.fs_payload().sample_mask_in_reg, BRW_TYPE_UD);
    
       if (wm_prog_data->persample_dispatch == INTEL_NEVER)
          return coverage_mask;
    
       /* gl_SampleMaskIn[] comes from two sources: the input coverage mask,
        * and a mask representing which sample is being processed by the
        * current shader invocation.
        *
        * From the OES_sample_variables specification:
        * "When per-sample shading is active due to the use of a fragment input
        *  qualified by "sample" or due to the use of the gl_SampleID or
        *  gl_SamplePosition variables, only the bit for the current sample is
        *  set in gl_SampleMaskIn."
        */
       const brw_builder abld = bld.annotate("compute gl_SampleMaskIn");
    
       if (ntb.system_values[SYSTEM_VALUE_SAMPLE_ID].file == BAD_FILE)
          ntb.system_values[SYSTEM_VALUE_SAMPLE_ID] = emit_sampleid_setup(ntb);
    
       brw_reg one = abld.MOV(brw_imm_ud(1));
       brw_reg enabled_mask = abld.SHL(one, ntb.system_values[SYSTEM_VALUE_SAMPLE_ID]);
       brw_reg mask = abld.AND(enabled_mask, coverage_mask);
    
       if (wm_prog_data->persample_dispatch == INTEL_ALWAYS)
          return mask;
    
       brw_check_dynamic_msaa_flag(abld, wm_prog_data,
                                   INTEL_MSAA_FLAG_PERSAMPLE_DISPATCH);
       set_predicate(BRW_PREDICATE_NORMAL, abld.SEL(mask, mask, coverage_mask));
    
       return mask;
    }
    
    static brw_reg
    emit_shading_rate_setup(nir_to_brw_state &ntb)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld;
    
       assert(devinfo->ver >= 11);
    
       struct brw_wm_prog_data *wm_prog_data =
          brw_wm_prog_data(bld.shader->prog_data);
    
       /* Coarse pixel shading size fields overlap with other fields of not in
        * coarse pixel dispatch mode, so report 0 when that's not the case.
        */
       if (wm_prog_data->coarse_pixel_dispatch == INTEL_NEVER)
          return brw_imm_ud(0);
    
       const brw_builder abld = bld.annotate("compute fragment shading rate");
    
       /* The shading rates provided in the shader are the actual 2D shading
        * rate while the SPIR-V built-in is the enum value that has the shading
        * rate encoded as a bitfield.  Fortunately, the bitfield value is just
        * the shading rate divided by two and shifted.
        */
    
       /* r1.0 - 0:7 ActualCoarsePixelShadingSize.X */
       brw_reg actual_x = brw_reg(retype(brw_vec1_grf(1, 0), BRW_TYPE_UB));
       /* r1.0 - 15:8 ActualCoarsePixelShadingSize.Y */
       brw_reg actual_y = byte_offset(actual_x, 1);
    
       brw_reg int_rate_y = abld.SHR(actual_y, brw_imm_ud(1));
       brw_reg int_rate_x = abld.SHR(actual_x, brw_imm_ud(1));
    
       brw_reg rate = abld.OR(abld.SHL(int_rate_x, brw_imm_ud(2)), int_rate_y);
    
       if (wm_prog_data->coarse_pixel_dispatch == INTEL_ALWAYS)
          return rate;
    
       brw_check_dynamic_msaa_flag(abld, wm_prog_data,
                                   INTEL_MSAA_FLAG_COARSE_RT_WRITES);
       set_predicate(BRW_PREDICATE_NORMAL, abld.SEL(rate, rate, brw_imm_ud(0)));
    
       return rate;
    }
    
    /* Input data is organized with first the per-primitive values, followed
     * by per-vertex values.  The per-vertex will have interpolation information
     * associated, so use 4 components for each value.
     */
    
    /* The register location here is relative to the start of the URB
     * data.  It will get adjusted to be a real location before
     * generate_code() time.
     */
    static brw_reg
    brw_interp_reg(const brw_builder &bld, unsigned location,
                   unsigned channel, unsigned comp)
    {
       fs_visitor &s = *bld.shader;
       assert(s.stage == MESA_SHADER_FRAGMENT);
       assert(BITFIELD64_BIT(location) & ~s.nir->info.per_primitive_inputs);
    
       const struct brw_wm_prog_data *prog_data = brw_wm_prog_data(s.prog_data);
    
       assert(prog_data->urb_setup[location] >= 0);
       unsigned nr = prog_data->urb_setup[location];
       channel += prog_data->urb_setup_channel[location];
    
       /* Adjust so we start counting from the first per_vertex input. */
       assert(nr >= prog_data->num_per_primitive_inputs);
       nr -= prog_data->num_per_primitive_inputs;
    
       const unsigned per_vertex_start = prog_data->num_per_primitive_inputs;
       const unsigned regnr = per_vertex_start + (nr * 4) + channel;
    
       if (s.max_polygons > 1) {
          /* In multipolygon dispatch each plane parameter is a
           * dispatch_width-wide SIMD vector (see comment in
           * assign_urb_setup()), so we need to use offset() instead of
           * component() to select the specified parameter.
           */
          const brw_reg tmp = bld.vgrf(BRW_TYPE_UD);
          bld.MOV(tmp, offset(brw_attr_reg(regnr, BRW_TYPE_UD),
                              s.dispatch_width, comp));
          return retype(tmp, BRW_TYPE_F);
       } else {
          return component(brw_attr_reg(regnr, BRW_TYPE_F), comp);
       }
    }
    
    /* The register location here is relative to the start of the URB
     * data.  It will get adjusted to be a real location before
     * generate_code() time.
     */
    static brw_reg
    brw_per_primitive_reg(const brw_builder &bld, int location, unsigned comp)
    {
       fs_visitor &s = *bld.shader;
       assert(s.stage == MESA_SHADER_FRAGMENT);
       assert(BITFIELD64_BIT(location) & s.nir->info.per_primitive_inputs);
    
       const struct brw_wm_prog_data *prog_data = brw_wm_prog_data(s.prog_data);
    
       comp += prog_data->urb_setup_channel[location];
    
       assert(prog_data->urb_setup[location] >= 0);
    
       const unsigned regnr = prog_data->urb_setup[location] + comp / 4;
    
       assert(regnr < prog_data->num_per_primitive_inputs);
    
       if (s.max_polygons > 1) {
          /* In multipolygon dispatch each primitive constant is a
           * dispatch_width-wide SIMD vector (see comment in
           * assign_urb_setup()), so we need to use offset() instead of
           * component() to select the specified parameter.
           */
          const brw_reg tmp = bld.vgrf(BRW_TYPE_UD);
          bld.MOV(tmp, offset(brw_attr_reg(regnr, BRW_TYPE_UD),
                              s.dispatch_width, comp % 4));
          return retype(tmp, BRW_TYPE_F);
       } else {
          return component(brw_attr_reg(regnr, BRW_TYPE_F), comp % 4);
       }
    }
    
    static void
    fs_nir_emit_fs_intrinsic(nir_to_brw_state &ntb,
                             nir_intrinsic_instr *instr)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_FRAGMENT);
    
       brw_reg dest;
       if (nir_intrinsic_infos[instr->intrinsic].has_dest)
          dest = get_nir_def(ntb, instr->def);
    
       switch (instr->intrinsic) {
       case nir_intrinsic_load_front_face:
          bld.MOV(retype(dest, BRW_TYPE_D), emit_frontfacing_interpolation(ntb));
          break;
    
       case nir_intrinsic_load_sample_pos:
       case nir_intrinsic_load_sample_pos_or_center: {
          brw_reg sample_pos = ntb.system_values[SYSTEM_VALUE_SAMPLE_POS];
          assert(sample_pos.file != BAD_FILE);
          dest.type = sample_pos.type;
          bld.MOV(dest, sample_pos);
          bld.MOV(offset(dest, bld, 1), offset(sample_pos, bld, 1));
          break;
       }
    
       case nir_intrinsic_load_layer_id:
          dest.type = BRW_TYPE_UD;
          bld.MOV(dest, fetch_render_target_array_index(bld));
          break;
    
       case nir_intrinsic_is_helper_invocation:
          emit_is_helper_invocation(ntb, dest);
          break;
    
       case nir_intrinsic_load_helper_invocation:
       case nir_intrinsic_load_sample_mask_in:
       case nir_intrinsic_load_sample_id:
       case nir_intrinsic_load_frag_shading_rate: {
          gl_system_value sv = nir_system_value_from_intrinsic(instr->intrinsic);
          brw_reg val = ntb.system_values[sv];
          assert(val.file != BAD_FILE);
          dest.type = val.type;
          bld.MOV(dest, val);
          break;
       }
    
       case nir_intrinsic_store_output: {
          const brw_reg src = get_nir_src(ntb, instr->src[0], -1);
          const unsigned store_offset = nir_src_as_uint(instr->src[1]);
          const unsigned location = nir_intrinsic_base(instr) +
             SET_FIELD(store_offset, BRW_NIR_FRAG_OUTPUT_LOCATION);
          const brw_reg new_dest =
             offset(retype(alloc_frag_output(ntb, location), src.type),
                    bld, nir_intrinsic_component(instr));
    
          brw_combine_with_vec(bld, new_dest, src, instr->num_components);
          break;
       }
    
       case nir_intrinsic_load_output: {
          const unsigned l = GET_FIELD(nir_intrinsic_base(instr),
                                       BRW_NIR_FRAG_OUTPUT_LOCATION);
          assert(l >= FRAG_RESULT_DATA0);
          const unsigned load_offset = nir_src_as_uint(instr->src[0]);
          const unsigned target = l - FRAG_RESULT_DATA0 + load_offset;
          const brw_reg tmp = bld.vgrf(dest.type, 4);
    
          if (reinterpret_cast<const brw_wm_prog_key *>(s.key)->coherent_fb_fetch)
             emit_coherent_fb_read(bld, tmp, target);
          else
             emit_non_coherent_fb_read(ntb, bld, tmp, target);
    
          brw_combine_with_vec(bld, dest,
                               offset(tmp, bld, nir_intrinsic_component(instr)),
                               instr->num_components);
          break;
       }
    
       case nir_intrinsic_demote:
       case nir_intrinsic_terminate:
       case nir_intrinsic_demote_if:
       case nir_intrinsic_terminate_if: {
          /* We track our discarded pixels in f0.1/f1.0.  By predicating on it, we
           * can update just the flag bits that aren't yet discarded.  If there's
           * no condition, we emit a CMP of g0 != g0, so all currently executing
           * channels will get turned off.
           */
          fs_inst *cmp = NULL;
          if (instr->intrinsic == nir_intrinsic_demote_if ||
              instr->intrinsic == nir_intrinsic_terminate_if) {
             nir_alu_instr *alu = nir_src_as_alu_instr(instr->src[0]);
    
             if (alu != NULL &&
                 alu->op != nir_op_bcsel) {
                /* Re-emit the instruction that generated the Boolean value, but
                 * do not store it.  Since this instruction will be conditional,
                 * other instructions that want to use the real Boolean value may
                 * get garbage.  This was a problem for piglit's fs-discard-exit-2
                 * test.
                 *
                 * Ideally we'd detect that the instruction cannot have a
                 * conditional modifier before emitting the instructions.  Alas,
                 * that is nigh impossible.  Instead, we're going to assume the
                 * instruction (or last instruction) generated can have a
                 * conditional modifier.  If it cannot, fallback to the old-style
                 * compare, and hope dead code elimination will clean up the
                 * extra instructions generated.
                 */
                fs_nir_emit_alu(ntb, alu, false);
    
                cmp = (fs_inst *) s.instructions.get_tail();
                if (cmp->conditional_mod == BRW_CONDITIONAL_NONE) {
                   if (cmp->can_do_cmod())
                      cmp->conditional_mod = BRW_CONDITIONAL_Z;
                   else
                      cmp = NULL;
                } else {
                   /* The old sequence that would have been generated is,
                    * basically, bool_result == false.  This is equivalent to
                    * !bool_result, so negate the old modifier.
                    *
                    * Unfortunately, we can't do this to most float comparisons
                    * because of NaN, so we'll have to fallback to the old-style
                    * compare.
                    *
                    * For example, this code (after negation):
                    *    (+f1.0) cmp.ge.f1.0(8) null<1>F g30<8,8,1>F     0x0F
                    * will provide different results from this:
                    *    cmp.l.f0.0(8)   g31<1>F         g30<1,1,0>F     0x0F
                    *    (+f1.0) cmp.z.f1.0(8) null<1>D  g31<8,8,1>D     0D
                    * because both (NaN >= 0) == false and (NaN < 0) == false.
                    *
                    * It will still work for == and != though, because
                    * (NaN == x) == false and (NaN != x) == true.
                    */
                   if (brw_type_is_float(cmp->src[0].type) &&
                       cmp->conditional_mod != BRW_CONDITIONAL_EQ &&
                       cmp->conditional_mod != BRW_CONDITIONAL_NEQ) {
                      cmp = NULL;
                   } else {
                      cmp->conditional_mod = brw_negate_cmod(cmp->conditional_mod);
                   }
                }
             }
    
             if (cmp == NULL) {
                cmp = bld.CMP(bld.null_reg_f(), get_nir_src(ntb, instr->src[0]),
                              brw_imm_d(0), BRW_CONDITIONAL_Z);
             }
          } else {
             brw_reg some_reg = brw_reg(retype(brw_vec8_grf(0, 0), BRW_TYPE_UW));
             cmp = bld.CMP(bld.null_reg_f(), some_reg, some_reg, BRW_CONDITIONAL_NZ);
          }
    
          cmp->predicate = BRW_PREDICATE_NORMAL;
          cmp->flag_subreg = sample_mask_flag_subreg(s);
    
          fs_inst *jump = bld.emit(BRW_OPCODE_HALT);
          jump->flag_subreg = sample_mask_flag_subreg(s);
          jump->predicate_inverse = true;
    
          if (instr->intrinsic == nir_intrinsic_terminate ||
              instr->intrinsic == nir_intrinsic_terminate_if) {
             jump->predicate = BRW_PREDICATE_NORMAL;
          } else {
             /* Only jump when the whole quad is demoted.  For historical
              * reasons this is also used for discard.
              */
             jump->predicate = (devinfo->ver >= 20 ? XE2_PREDICATE_ANY :
                                BRW_PREDICATE_ALIGN1_ANY4H);
          }
          break;
       }
    
       case nir_intrinsic_load_input:
       case nir_intrinsic_load_per_primitive_input: {
          /* In Fragment Shaders load_input is used either for flat inputs or
           * per-primitive inputs.
           */
          assert(instr->def.bit_size == 32);
          unsigned base = nir_intrinsic_base(instr);
          unsigned comp = nir_intrinsic_component(instr);
          unsigned num_components = instr->num_components;
    
          /* TODO(mesh): Multiview. Verify and handle these special cases for Mesh. */
    
          if (base == VARYING_SLOT_LAYER) {
             dest.type = BRW_TYPE_UD;
             bld.MOV(dest, fetch_render_target_array_index(bld));
             break;
          } else if (base == VARYING_SLOT_VIEWPORT) {
             dest.type = BRW_TYPE_UD;
             bld.MOV(dest, fetch_viewport_index(bld));
             break;
          }
    
          if (BITFIELD64_BIT(base) & s.nir->info.per_primitive_inputs) {
             assert(base != VARYING_SLOT_PRIMITIVE_INDICES);
             for (unsigned int i = 0; i < num_components; i++) {
                bld.MOV(offset(dest, bld, i),
                        retype(brw_per_primitive_reg(bld, base, comp + i), dest.type));
             }
          } else {
             /* Gfx20+ packs the plane parameters of a single logical
              * input in a vec3 format instead of the previously used vec4
              * format.
              */
             const unsigned k = devinfo->ver >= 20 ? 0 : 3;
             for (unsigned int i = 0; i < num_components; i++) {
                bld.MOV(offset(dest, bld, i),
                        retype(brw_interp_reg(bld, base, comp + i, k), dest.type));
             }
          }
          break;
       }
    
       case nir_intrinsic_load_fs_input_interp_deltas: {
          assert(s.stage == MESA_SHADER_FRAGMENT);
          assert(nir_src_as_uint(instr->src[0]) == 0);
          const unsigned base = nir_intrinsic_base(instr);
          const unsigned comp = nir_intrinsic_component(instr);
          dest.type = BRW_TYPE_F;
    
          /* Gfx20+ packs the plane parameters of a single logical
           * input in a vec3 format instead of the previously used vec4
           * format.
           */
          if (devinfo->ver >= 20) {
             bld.MOV(offset(dest, bld, 0), brw_interp_reg(bld, base, comp, 0));
             bld.MOV(offset(dest, bld, 1), brw_interp_reg(bld, base, comp, 2));
             bld.MOV(offset(dest, bld, 2), brw_interp_reg(bld, base, comp, 1));
          } else {
             bld.MOV(offset(dest, bld, 0), brw_interp_reg(bld, base, comp, 3));
             bld.MOV(offset(dest, bld, 1), brw_interp_reg(bld, base, comp, 1));
             bld.MOV(offset(dest, bld, 2), brw_interp_reg(bld, base, comp, 0));
          }
    
          break;
       }
    
       case nir_intrinsic_load_barycentric_pixel:
       case nir_intrinsic_load_barycentric_centroid:
       case nir_intrinsic_load_barycentric_sample: {
          /* Use the delta_xy values computed from the payload */
          enum intel_barycentric_mode bary = brw_barycentric_mode(
             reinterpret_cast<const brw_wm_prog_key *>(s.key), instr);
          const brw_reg srcs[] = { offset(s.delta_xy[bary], bld, 0),
                                  offset(s.delta_xy[bary], bld, 1) };
          bld.LOAD_PAYLOAD(dest, srcs, ARRAY_SIZE(srcs), 0);
          break;
       }
    
       case nir_intrinsic_load_barycentric_at_sample: {
          const glsl_interp_mode interpolation =
             (enum glsl_interp_mode) nir_intrinsic_interp_mode(instr);
    
          if (devinfo->ver >= 20) {
             emit_pixel_interpolater_alu_at_sample(
                bld, dest, retype(get_nir_src(ntb, instr->src[0]),
                                  BRW_TYPE_UD),
                interpolation);
    
          } else {
             const brw_reg sample_src = retype(get_nir_src(ntb, instr->src[0]),
                                               BRW_TYPE_UD);
             const brw_reg sample_id = bld.emit_uniformize(sample_src);
             const brw_reg msg_data = component(bld.group(8, 0).vgrf(BRW_TYPE_UD), 0);
    
             bld.exec_all().group(1, 0).SHL(msg_data, sample_id, brw_imm_ud(4u));
    
             brw_reg flag_reg;
             struct brw_wm_prog_key *wm_prog_key = (struct brw_wm_prog_key *) s.key;
             if (wm_prog_key->multisample_fbo == INTEL_SOMETIMES) {
                struct brw_wm_prog_data *wm_prog_data = brw_wm_prog_data(s.prog_data);
    
                brw_check_dynamic_msaa_flag(bld.exec_all().group(8, 0),
                                            wm_prog_data,
                                            INTEL_MSAA_FLAG_MULTISAMPLE_FBO);
                flag_reg = brw_flag_reg(0, 0);
             }
    
             emit_pixel_interpolater_send(bld,
                                          FS_OPCODE_INTERPOLATE_AT_SAMPLE,
                                          dest,
                                          brw_reg(), /* src */
                                          msg_data,
                                          flag_reg,
                                          interpolation);
          }
          break;
       }
    
       case nir_intrinsic_load_barycentric_at_offset: {
          const glsl_interp_mode interpolation =
             (enum glsl_interp_mode) nir_intrinsic_interp_mode(instr);
    
          if (devinfo->ver >= 20) {
             emit_pixel_interpolater_alu_at_offset(
                bld, dest,
                retype(get_nir_src(ntb, instr->src[0], -1), BRW_TYPE_F),
                interpolation);
    
          } else if (nir_const_value *const_offset = nir_src_as_const_value(instr->src[0])) {
             assert(nir_src_bit_size(instr->src[0]) == 32);
             unsigned off_x = const_offset[0].u32 & 0xf;
             unsigned off_y = const_offset[1].u32 & 0xf;
    
             emit_pixel_interpolater_send(bld,
                                          FS_OPCODE_INTERPOLATE_AT_SHARED_OFFSET,
                                          dest,
                                          brw_reg(), /* src */
                                          brw_imm_ud(off_x | (off_y << 4)),
                                          brw_reg(), /* flag_reg */
                                          interpolation);
          } else {
             brw_reg src = retype(get_nir_src(ntb, instr->src[0], -1), BRW_TYPE_D);
             const enum opcode opcode = FS_OPCODE_INTERPOLATE_AT_PER_SLOT_OFFSET;
             emit_pixel_interpolater_send(bld,
                                          opcode,
                                          dest,
                                          src,
                                          brw_imm_ud(0u),
                                          brw_reg(), /* flag_reg */
                                          interpolation);
          }
          break;
       }
    
       case nir_intrinsic_load_frag_coord: {
          brw_reg comps[4] = { s.pixel_x, s.pixel_y, s.pixel_z, s.wpos_w };
          bld.VEC(dest, comps, 4);
          break;
       }
    
       case nir_intrinsic_load_interpolated_input: {
          assert(instr->src[0].ssa &&
                 instr->src[0].ssa->parent_instr->type == nir_instr_type_intrinsic);
          nir_intrinsic_instr *bary_intrinsic =
             nir_instr_as_intrinsic(instr->src[0].ssa->parent_instr);
          nir_intrinsic_op bary_intrin = bary_intrinsic->intrinsic;
          brw_reg dst_xy;
    
          if (bary_intrin == nir_intrinsic_load_barycentric_at_offset ||
              bary_intrin == nir_intrinsic_load_barycentric_at_sample) {
             /* Use the result of the PI message. */
             dst_xy = retype(get_nir_src(ntb, instr->src[0], -1), BRW_TYPE_F);
          } else {
             /* Use the delta_xy values computed from the payload */
             enum intel_barycentric_mode bary = brw_barycentric_mode(
                reinterpret_cast<const brw_wm_prog_key *>(s.key), bary_intrinsic);
             dst_xy = s.delta_xy[bary];
          }
    
          for (unsigned int i = 0; i < instr->num_components; i++) {
             brw_reg interp =
                brw_interp_reg(bld, nir_intrinsic_base(instr),
                               nir_intrinsic_component(instr) + i, 0);
             interp.type = BRW_TYPE_F;
             dest.type = BRW_TYPE_F;
    
             bld.PLN(offset(dest, bld, i), interp, dst_xy);
          }
          break;
       }
    
       default:
          fs_nir_emit_intrinsic(ntb, bld, instr);
          break;
       }
    }
    
    static unsigned
    brw_workgroup_size(fs_visitor &s)
    {
       assert(gl_shader_stage_uses_workgroup(s.stage));
       assert(!s.nir->info.workgroup_size_variable);
       const struct brw_cs_prog_data *cs = brw_cs_prog_data(s.prog_data);
       return cs->local_size[0] * cs->local_size[1] * cs->local_size[2];
    }
    
    static void
    fs_nir_emit_cs_intrinsic(nir_to_brw_state &ntb,
                             nir_intrinsic_instr *instr)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(gl_shader_stage_uses_workgroup(s.stage));
       struct brw_cs_prog_data *cs_prog_data = brw_cs_prog_data(s.prog_data);
    
       brw_reg dest;
       if (nir_intrinsic_infos[instr->intrinsic].has_dest)
          dest = get_nir_def(ntb, instr->def);
    
       const brw_builder xbld = dest.is_scalar ? bld.scalar_group() : bld;
    
       switch (instr->intrinsic) {
       case nir_intrinsic_barrier:
          if (nir_intrinsic_memory_scope(instr) != SCOPE_NONE)
             fs_nir_emit_intrinsic(ntb, bld, instr);
          if (nir_intrinsic_execution_scope(instr) == SCOPE_WORKGROUP) {
             /* The whole workgroup fits in a single HW thread, so all the
              * invocations are already executed lock-step.  Instead of an actual
              * barrier just emit a scheduling fence, that will generate no code.
              */
             if (!s.nir->info.workgroup_size_variable &&
                 brw_workgroup_size(s) <= s.dispatch_width) {
                bld.exec_all().group(1, 0).emit(FS_OPCODE_SCHEDULING_FENCE);
                break;
             }
    
             emit_barrier(ntb);
             cs_prog_data->uses_barrier = true;
          }
          break;
    
       case nir_intrinsic_load_inline_data_intel: {
          const cs_thread_payload &payload = s.cs_payload();
          unsigned inline_stride = brw_type_size_bytes(dest.type);
          for (unsigned c = 0; c < instr->def.num_components; c++) {
             xbld.MOV(offset(dest, xbld, c),
                      retype(
                         byte_offset(payload.inline_parameter,
                                     nir_intrinsic_base(instr) +
                                     c * inline_stride),
                         dest.type));
          }
          break;
       }
    
       case nir_intrinsic_load_subgroup_id:
          s.cs_payload().load_subgroup_id(bld, dest);
          break;
    
       case nir_intrinsic_load_local_invocation_id:
          /* This is only used for hardware generated local IDs. */
          assert(cs_prog_data->generate_local_id);
    
          dest.type = BRW_TYPE_UD;
    
          for (unsigned i = 0; i < 3; i++)
             bld.MOV(offset(dest, bld, i), s.cs_payload().local_invocation_id[i]);
          break;
    
       case nir_intrinsic_load_workgroup_id: {
          brw_reg val = ntb.system_values[SYSTEM_VALUE_WORKGROUP_ID];
          const brw_builder ubld = bld.scalar_group();
    
          assert(val.file != BAD_FILE);
          assert(val.is_scalar);
    
          dest.type = val.type;
          for (unsigned i = 0; i < 3; i++)
             ubld.MOV(offset(dest, ubld, i), offset(val, ubld, i));
          break;
       }
    
       case nir_intrinsic_load_num_workgroups: {
          assert(instr->def.bit_size == 32);
    
          cs_prog_data->uses_num_work_groups = true;
    
          brw_reg srcs[MEMORY_LOGICAL_NUM_SRCS];
          srcs[MEMORY_LOGICAL_OPCODE] = brw_imm_ud(LSC_OP_LOAD);
          srcs[MEMORY_LOGICAL_MODE] = brw_imm_ud(MEMORY_MODE_UNTYPED);
          srcs[MEMORY_LOGICAL_BINDING_TYPE] = brw_imm_ud(LSC_ADDR_SURFTYPE_BTI);
          srcs[MEMORY_LOGICAL_BINDING] = brw_imm_ud(0);
          srcs[MEMORY_LOGICAL_ADDRESS] = brw_imm_ud(0);
          srcs[MEMORY_LOGICAL_COORD_COMPONENTS] = brw_imm_ud(1);
          srcs[MEMORY_LOGICAL_ALIGNMENT] = brw_imm_ud(4);
          srcs[MEMORY_LOGICAL_DATA_SIZE] = brw_imm_ud(LSC_DATA_SIZE_D32);
          srcs[MEMORY_LOGICAL_COMPONENTS] = brw_imm_ud(3);
          srcs[MEMORY_LOGICAL_FLAGS] = brw_imm_ud(0);
    
          fs_inst *inst =
             bld.emit(SHADER_OPCODE_MEMORY_LOAD_LOGICAL,
                      dest, srcs, MEMORY_LOGICAL_NUM_SRCS);
          inst->size_written = 3 * s.dispatch_width * 4;
          break;
       }
    
       case nir_intrinsic_load_workgroup_size: {
          /* Should have been lowered by brw_nir_lower_cs_intrinsics() or
           * iris_setup_uniforms() for the variable group size case.
           */
          unreachable("Should have been lowered");
          break;
       }
    
       case nir_intrinsic_dpas_intel: {
          const unsigned sdepth = nir_intrinsic_systolic_depth(instr);
          const unsigned rcount = nir_intrinsic_repeat_count(instr);
    
          const brw_reg_type dest_type =
             brw_type_for_nir_type(devinfo, nir_intrinsic_dest_type(instr));
          const brw_reg_type src_type =
             brw_type_for_nir_type(devinfo, nir_intrinsic_src_type(instr));
    
          dest = retype(dest, dest_type);
          brw_reg src0 = retype(get_nir_src(ntb, instr->src[0]), dest_type);
    
          brw_builder bld16 = bld.exec_all().group(16, 0);
          brw_builder bldn = devinfo->ver >= 20 ? bld16 : bld.exec_all().group(8, 0);
    
          bldn.DPAS(dest,
                    src0,
                    retype(get_nir_src(ntb, instr->src[2]), src_type),
                    retype(get_nir_src(ntb, instr->src[1]), src_type),
                    sdepth,
                    rcount)
             ->saturate = nir_intrinsic_saturate(instr);
    
          cs_prog_data->uses_systolic = true;
          break;
       }
    
       default:
          fs_nir_emit_intrinsic(ntb, bld, instr);
          break;
       }
    }
    
    static void
    emit_rt_lsc_fence(const brw_builder &bld,
                      enum lsc_fence_scope scope,
                      enum lsc_flush_type flush_type)
    {
       const intel_device_info *devinfo = bld.shader->devinfo;
    
       const brw_builder ubld = bld.exec_all().group(8, 0);
       brw_reg tmp = ubld.vgrf(BRW_TYPE_UD);
       fs_inst *send = ubld.emit(SHADER_OPCODE_SEND, tmp,
                                 brw_imm_ud(0) /* desc */,
                                 brw_imm_ud(0) /* ex_desc */,
                                 brw_vec8_grf(0, 0) /* payload */);
       send->sfid = GFX12_SFID_UGM;
       send->desc = lsc_fence_msg_desc(devinfo, scope, flush_type, true);
       send->mlen = reg_unit(devinfo); /* g0 header */
       send->ex_mlen = 0;
       /* Temp write for scheduling */
       send->size_written = REG_SIZE * reg_unit(devinfo);
       send->send_has_side_effects = true;
    
       ubld.emit(FS_OPCODE_SCHEDULING_FENCE, ubld.null_reg_ud(), tmp);
    }
    
    
    static void
    fs_nir_emit_bs_intrinsic(nir_to_brw_state &ntb,
                             nir_intrinsic_instr *instr)
    {
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(brw_shader_stage_is_bindless(s.stage));
       const bs_thread_payload &payload = s.bs_payload();
    
       brw_reg dest;
       if (nir_intrinsic_infos[instr->intrinsic].has_dest)
          dest = get_nir_def(ntb, instr->def);
    
       const brw_builder xbld = dest.is_scalar ? bld.scalar_group() : bld;
    
       switch (instr->intrinsic) {
       case nir_intrinsic_load_btd_global_arg_addr_intel:
          xbld.MOV(dest, retype(payload.global_arg_ptr, dest.type));
          break;
    
       case nir_intrinsic_load_btd_local_arg_addr_intel:
          xbld.MOV(dest, retype(payload.local_arg_ptr, dest.type));
          break;
    
       case nir_intrinsic_load_btd_shader_type_intel:
          payload.load_shader_type(xbld, dest);
          break;
    
       default:
          fs_nir_emit_intrinsic(ntb, bld, instr);
          break;
       }
    }
    
    static brw_reduce_op
    brw_reduce_op_for_nir_reduction_op(nir_op op)
    {
       switch (op) {
       case nir_op_iadd: return BRW_REDUCE_OP_ADD;
       case nir_op_fadd: return BRW_REDUCE_OP_ADD;
       case nir_op_imul: return BRW_REDUCE_OP_MUL;
       case nir_op_fmul: return BRW_REDUCE_OP_MUL;
       case nir_op_imin: return BRW_REDUCE_OP_MIN;
       case nir_op_umin: return BRW_REDUCE_OP_MIN;
       case nir_op_fmin: return BRW_REDUCE_OP_MIN;
       case nir_op_imax: return BRW_REDUCE_OP_MAX;
       case nir_op_umax: return BRW_REDUCE_OP_MAX;
       case nir_op_fmax: return BRW_REDUCE_OP_MAX;
       case nir_op_iand: return BRW_REDUCE_OP_AND;
       case nir_op_ior:  return BRW_REDUCE_OP_OR;
       case nir_op_ixor: return BRW_REDUCE_OP_XOR;
       default:
          unreachable("Invalid reduction operation");
       }
    }
    
    static brw_reg
    get_nir_image_intrinsic_image(nir_to_brw_state &ntb, const brw_builder &bld,
                                  nir_intrinsic_instr *instr)
    {
       brw_reg surf_index = get_nir_src_imm(ntb, instr->src[0]);
       enum brw_reg_type type = brw_type_with_size(BRW_TYPE_UD,
                                                   brw_type_size_bits(surf_index.type));
    
       return bld.emit_uniformize(retype(surf_index, type));
    }
    
    static brw_reg
    get_nir_buffer_intrinsic_index(nir_to_brw_state &ntb, const brw_builder &bld,
                                   nir_intrinsic_instr *instr, bool *no_mask_handle = NULL)
    {
       /* SSBO stores are weird in that their index is in src[1] */
       const bool is_store =
          instr->intrinsic == nir_intrinsic_store_ssbo ||
          instr->intrinsic == nir_intrinsic_store_ssbo_block_intel;
       nir_src src = is_store ? instr->src[1] : instr->src[0];
    
       brw_reg surf_index = get_nir_src_imm(ntb, src);
    
       if (no_mask_handle)
          *no_mask_handle = surf_index.is_scalar || surf_index.file == IMM;
    
       enum brw_reg_type type = brw_type_with_size(BRW_TYPE_UD,
                                                   brw_type_size_bits(surf_index.type));
    
       return bld.emit_uniformize(retype(surf_index, type));
    }
    
    /**
     * The offsets we get from NIR act as if each SIMD channel has it's own blob
     * of contiguous space.  However, if we actually place each SIMD channel in
     * it's own space, we end up with terrible cache performance because each SIMD
     * channel accesses a different cache line even when they're all accessing the
     * same byte offset.  To deal with this problem, we swizzle the address using
     * a simple algorithm which ensures that any time a SIMD message reads or
     * writes the same address, it's all in the same cache line.  We have to keep
     * the bottom two bits fixed so that we can read/write up to a dword at a time
     * and the individual element is contiguous.  We do this by splitting the
     * address as follows:
     *
     *    31                             4-6           2          0
     *    +-------------------------------+------------+----------+
     *    |        Hi address bits        | chan index | addr low |
     *    +-------------------------------+------------+----------+
     *
     * In other words, the bottom two address bits stay, and the top 30 get
     * shifted up so that we can stick the SIMD channel index in the middle.  This
     * way, we can access 8, 16, or 32-bit elements and, when accessing a 32-bit
     * at the same logical offset, the scratch read/write instruction acts on
     * continuous elements and we get good cache locality.
     */
    static brw_reg
    swizzle_nir_scratch_addr(nir_to_brw_state &ntb,
                             const brw_builder &bld,
                             const nir_src &nir_addr_src,
                             bool in_dwords)
    {
       fs_visitor &s = ntb.s;
    
       const brw_reg chan_index = bld.LOAD_SUBGROUP_INVOCATION();
       const unsigned chan_index_bits = ffs(s.dispatch_width) - 1;
    
       if (nir_src_is_const(nir_addr_src)) {
          unsigned nir_addr = nir_src_as_uint(nir_addr_src);
          if (in_dwords) {
             /* In this case, we know the address is aligned to a DWORD and we want
              * the final address in DWORDs.
              */
             return bld.OR(chan_index,
                           brw_imm_ud(nir_addr << (chan_index_bits - 2)));
          } else {
             /* This case is substantially more annoying because we have to pay
              * attention to those pesky two bottom bits.
              */
             unsigned addr_hi = (nir_addr & ~0x3u) << chan_index_bits;
             unsigned addr_lo = (nir_addr &  0x3u);
    
             return bld.OR(bld.SHL(chan_index, brw_imm_ud(2)),
                           brw_imm_ud(addr_lo | addr_hi));
          }
       }
    
       const brw_reg nir_addr =
          retype(get_nir_src(ntb, nir_addr_src), BRW_TYPE_UD);
    
       if (in_dwords) {
          /* In this case, we know the address is aligned to a DWORD and we want
           * the final address in DWORDs.
           */
          return bld.OR(bld.SHL(nir_addr, brw_imm_ud(chan_index_bits - 2)),
                        chan_index);
       } else {
          /* This case substantially more annoying because we have to pay
           * attention to those pesky two bottom bits.
           */
          brw_reg chan_addr = bld.SHL(chan_index, brw_imm_ud(2));
          brw_reg addr_bits =
             bld.OR(bld.AND(nir_addr, brw_imm_ud(0x3u)),
                    bld.SHL(bld.AND(nir_addr, brw_imm_ud(~0x3u)),
                            brw_imm_ud(chan_index_bits)));
          return bld.OR(addr_bits, chan_addr);
       }
    }
    
    static unsigned
    choose_block_size_dwords(const intel_device_info *devinfo, unsigned dwords)
    {
       const unsigned min_block = 8;
       const unsigned max_block = devinfo->has_lsc ? 64 : 32;
    
       const unsigned block = 1 << util_logbase2(dwords);
    
       return CLAMP(block, min_block, max_block);
    }
    
    static brw_reg
    increment_a64_address(const brw_builder &_bld, brw_reg address, uint32_t v, bool use_no_mask)
    {
       const brw_builder bld = use_no_mask ? _bld.exec_all().group(8, 0) : _bld;
    
       if (bld.shader->devinfo->has_64bit_int) {
          struct brw_reg imm = brw_imm_reg(address.type);
          imm.u64 = v;
          return bld.ADD(address, imm);
       } else {
          brw_reg dst = bld.vgrf(BRW_TYPE_UQ);
          brw_reg dst_low = subscript(dst, BRW_TYPE_UD, 0);
          brw_reg dst_high = subscript(dst, BRW_TYPE_UD, 1);
          brw_reg src_low = subscript(address, BRW_TYPE_UD, 0);
          brw_reg src_high = subscript(address, BRW_TYPE_UD, 1);
    
          /* Add low and if that overflows, add carry to high. */
          bld.ADD(dst_low, src_low, brw_imm_ud(v))->conditional_mod = BRW_CONDITIONAL_O;
          bld.ADD(dst_high, src_high, brw_imm_ud(0x1))->predicate = BRW_PREDICATE_NORMAL;
          return dst_low;
       }
    }
    
    static brw_reg
    emit_fence(const brw_builder &bld, enum opcode opcode,
               uint8_t sfid, uint32_t desc,
               bool commit_enable, uint8_t bti)
    {
       assert(opcode == SHADER_OPCODE_INTERLOCK ||
              opcode == SHADER_OPCODE_MEMORY_FENCE);
    
       brw_reg dst = bld.vgrf(BRW_TYPE_UD);
       fs_inst *fence = bld.emit(opcode, dst, brw_vec8_grf(0, 0),
                                 brw_imm_ud(commit_enable),
                                 brw_imm_ud(bti));
       fence->sfid = sfid;
       fence->desc = desc;
    
       return dst;
    }
    
    static uint32_t
    lsc_fence_descriptor_for_intrinsic(const struct intel_device_info *devinfo,
                                       nir_intrinsic_instr *instr)
    {
       assert(devinfo->has_lsc);
    
       enum lsc_fence_scope scope = LSC_FENCE_LOCAL;
       enum lsc_flush_type flush_type = LSC_FLUSH_TYPE_NONE;
    
       if (nir_intrinsic_has_memory_scope(instr)) {
          switch (nir_intrinsic_memory_scope(instr)) {
          case SCOPE_DEVICE:
          case SCOPE_QUEUE_FAMILY:
             scope = LSC_FENCE_TILE;
             flush_type = LSC_FLUSH_TYPE_EVICT;
             break;
          case SCOPE_WORKGROUP:
             scope = LSC_FENCE_THREADGROUP;
             break;
          case SCOPE_SHADER_CALL:
          case SCOPE_INVOCATION:
          case SCOPE_SUBGROUP:
          case SCOPE_NONE:
             break;
          }
       } else {
          /* No scope defined. */
          scope = LSC_FENCE_TILE;
          flush_type = LSC_FLUSH_TYPE_EVICT;
       }
       return lsc_fence_msg_desc(devinfo, scope, flush_type, true);
    }
    
    /**
     * Create a MOV to read the timestamp register.
     */
    static brw_reg
    get_timestamp(const brw_builder &bld)
    {
       fs_visitor &s = *bld.shader;
    
       brw_reg ts = brw_reg(retype(brw_vec4_reg(ARF,
                                              BRW_ARF_TIMESTAMP, 0), BRW_TYPE_UD));
    
       brw_reg dst = brw_vgrf(s.alloc.allocate(1), BRW_TYPE_UD);
    
       /* We want to read the 3 fields we care about even if it's not enabled in
        * the dispatch.
        */
       bld.group(4, 0).exec_all().MOV(dst, ts);
    
       return dst;
    }
    
    static unsigned
    component_from_intrinsic(nir_intrinsic_instr *instr)
    {
       if (nir_intrinsic_has_component(instr))
          return nir_intrinsic_component(instr);
       else
          return 0;
    }
    
    static void
    adjust_handle_and_offset(const brw_builder &bld,
                             brw_reg &urb_handle,
                             unsigned &urb_global_offset)
    {
       /* Make sure that URB global offset is below 2048 (2^11), because
        * that's the maximum possible value encoded in Message Descriptor.
        */
       unsigned adjustment = (urb_global_offset >> 11) << 11;
    
       if (adjustment) {
          brw_builder ubld8 = bld.group(8, 0).exec_all();
          /* Allocate new register to not overwrite the shared URB handle. */
          urb_handle = ubld8.ADD(urb_handle, brw_imm_ud(adjustment));
          urb_global_offset -= adjustment;
       }
    }
    
    static void
    emit_urb_direct_vec4_write(const brw_builder &bld,
                               unsigned urb_global_offset,
                               const brw_reg &src,
                               brw_reg urb_handle,
                               unsigned dst_comp_offset,
                               unsigned comps,
                               unsigned mask)
    {
       for (unsigned q = 0; q < bld.dispatch_width() / 8; q++) {
          brw_builder bld8 = bld.group(8, q);
    
          brw_reg payload_srcs[8];
          unsigned length = 0;
    
          for (unsigned i = 0; i < dst_comp_offset; i++)
             payload_srcs[length++] = reg_undef;
    
          for (unsigned c = 0; c < comps; c++)
             payload_srcs[length++] = quarter(offset(src, bld, c), q);
    
          brw_reg srcs[URB_LOGICAL_NUM_SRCS];
          srcs[URB_LOGICAL_SRC_HANDLE] = urb_handle;
          srcs[URB_LOGICAL_SRC_CHANNEL_MASK] = brw_imm_ud(mask << 16);
          srcs[URB_LOGICAL_SRC_DATA] = brw_vgrf(bld.shader->alloc.allocate(length),
                                                BRW_TYPE_F);
          srcs[URB_LOGICAL_SRC_COMPONENTS] = brw_imm_ud(length);
          bld8.LOAD_PAYLOAD(srcs[URB_LOGICAL_SRC_DATA], payload_srcs, length, 0);
    
          fs_inst *inst = bld8.emit(SHADER_OPCODE_URB_WRITE_LOGICAL,
                                    reg_undef, srcs, ARRAY_SIZE(srcs));
          inst->offset = urb_global_offset;
          assert(inst->offset < 2048);
       }
    }
    
    static void
    emit_urb_direct_writes(const brw_builder &bld, nir_intrinsic_instr *instr,
                           const brw_reg &src, brw_reg urb_handle)
    {
       assert(nir_src_bit_size(instr->src[0]) == 32);
    
       nir_src *offset_nir_src = nir_get_io_offset_src(instr);
       assert(nir_src_is_const(*offset_nir_src));
    
       const unsigned comps = nir_src_num_components(instr->src[0]);
       assert(comps <= 4);
    
       const unsigned offset_in_dwords = nir_intrinsic_base(instr) +
                                         nir_src_as_uint(*offset_nir_src) +
                                         component_from_intrinsic(instr);
    
       /* URB writes are vec4 aligned but the intrinsic offsets are in dwords.
        * We can write up to 8 dwords, so single vec4 write is enough.
        */
       const unsigned comp_shift = offset_in_dwords % 4;
       const unsigned mask = nir_intrinsic_write_mask(instr) << comp_shift;
    
       unsigned urb_global_offset = offset_in_dwords / 4;
       adjust_handle_and_offset(bld, urb_handle, urb_global_offset);
    
       emit_urb_direct_vec4_write(bld, urb_global_offset, src, urb_handle,
                                  comp_shift, comps, mask);
    }
    
    static void
    emit_urb_direct_vec4_write_xe2(const brw_builder &bld,
                                   unsigned offset_in_bytes,
                                   const brw_reg &src,
                                   brw_reg urb_handle,
                                   unsigned comps,
                                   unsigned mask)
    {
       const struct intel_device_info *devinfo = bld.shader->devinfo;
       const unsigned runit = reg_unit(devinfo);
       const unsigned write_size = 8 * runit;
    
       if (offset_in_bytes > 0) {
          brw_builder bldall = bld.group(write_size, 0).exec_all();
          urb_handle = bldall.ADD(urb_handle, brw_imm_ud(offset_in_bytes));
       }
    
       for (unsigned q = 0; q < bld.dispatch_width() / write_size; q++) {
          brw_builder hbld = bld.group(write_size, q);
    
          assert(comps <= 4);
          brw_reg payload_srcs[4];
    
          for (unsigned c = 0; c < comps; c++)
             payload_srcs[c] = horiz_offset(offset(src, bld, c), write_size * q);
    
          brw_reg srcs[URB_LOGICAL_NUM_SRCS];
          srcs[URB_LOGICAL_SRC_HANDLE] = urb_handle;
          srcs[URB_LOGICAL_SRC_CHANNEL_MASK] = brw_imm_ud(mask << 16);
          int nr = bld.shader->alloc.allocate(comps * runit);
          srcs[URB_LOGICAL_SRC_DATA] = brw_vgrf(nr, BRW_TYPE_F);
          srcs[URB_LOGICAL_SRC_COMPONENTS] = brw_imm_ud(comps);
          hbld.LOAD_PAYLOAD(srcs[URB_LOGICAL_SRC_DATA], payload_srcs, comps, 0);
    
          hbld.emit(SHADER_OPCODE_URB_WRITE_LOGICAL,
                    reg_undef, srcs, ARRAY_SIZE(srcs));
       }
    }
    
    static void
    emit_urb_direct_writes_xe2(const brw_builder &bld, nir_intrinsic_instr *instr,
                               const brw_reg &src, brw_reg urb_handle)
    {
       assert(nir_src_bit_size(instr->src[0]) == 32);
    
       nir_src *offset_nir_src = nir_get_io_offset_src(instr);
       assert(nir_src_is_const(*offset_nir_src));
    
       const unsigned comps = nir_src_num_components(instr->src[0]);
       assert(comps <= 4);
    
       const unsigned offset_in_dwords = nir_intrinsic_base(instr) +
                                         nir_src_as_uint(*offset_nir_src) +
                                         component_from_intrinsic(instr);
    
       const unsigned mask = nir_intrinsic_write_mask(instr);
    
       emit_urb_direct_vec4_write_xe2(bld, offset_in_dwords * 4, src,
                                        urb_handle, comps, mask);
    }
    
    static void
    emit_urb_indirect_vec4_write(const brw_builder &bld,
                                 const brw_reg &offset_src,
                                 unsigned base,
                                 const brw_reg &src,
                                 brw_reg urb_handle,
                                 unsigned dst_comp_offset,
                                 unsigned comps,
                                 unsigned mask)
    {
       for (unsigned q = 0; q < bld.dispatch_width() / 8; q++) {
          brw_builder bld8 = bld.group(8, q);
    
          /* offset is always positive, so signedness doesn't matter */
          assert(offset_src.type == BRW_TYPE_D || offset_src.type == BRW_TYPE_UD);
          brw_reg qtr = bld8.MOV(quarter(retype(offset_src, BRW_TYPE_UD), q));
          brw_reg off = bld8.SHR(bld8.ADD(qtr, brw_imm_ud(base)), brw_imm_ud(2));
    
          brw_reg payload_srcs[8];
          unsigned length = 0;
    
          for (unsigned i = 0; i < dst_comp_offset; i++)
             payload_srcs[length++] = reg_undef;
    
          for (unsigned c = 0; c < comps; c++)
             payload_srcs[length++] = quarter(offset(src, bld, c), q);
    
          brw_reg srcs[URB_LOGICAL_NUM_SRCS];
          srcs[URB_LOGICAL_SRC_HANDLE] = urb_handle;
          srcs[URB_LOGICAL_SRC_PER_SLOT_OFFSETS] = off;
          srcs[URB_LOGICAL_SRC_CHANNEL_MASK] = brw_imm_ud(mask << 16);
          srcs[URB_LOGICAL_SRC_DATA] = brw_vgrf(bld.shader->alloc.allocate(length),
                                                BRW_TYPE_F);
          srcs[URB_LOGICAL_SRC_COMPONENTS] = brw_imm_ud(length);
          bld8.LOAD_PAYLOAD(srcs[URB_LOGICAL_SRC_DATA], payload_srcs, length, 0);
    
          fs_inst *inst = bld8.emit(SHADER_OPCODE_URB_WRITE_LOGICAL,
                                    reg_undef, srcs, ARRAY_SIZE(srcs));
          inst->offset = 0;
       }
    }
    
    static void
    emit_urb_indirect_writes_mod(const brw_builder &bld, nir_intrinsic_instr *instr,
                                 const brw_reg &src, const brw_reg &offset_src,
                                 brw_reg urb_handle, unsigned mod)
    {
       assert(nir_src_bit_size(instr->src[0]) == 32);
    
       const unsigned comps = nir_src_num_components(instr->src[0]);
       assert(comps <= 4);
    
       const unsigned base_in_dwords = nir_intrinsic_base(instr) +
                                       component_from_intrinsic(instr);
    
       const unsigned comp_shift = mod;
       const unsigned mask = nir_intrinsic_write_mask(instr) << comp_shift;
    
       emit_urb_indirect_vec4_write(bld, offset_src, base_in_dwords, src,
                                    urb_handle, comp_shift, comps, mask);
    }
    
    static void
    emit_urb_indirect_writes_xe2(const brw_builder &bld, nir_intrinsic_instr *instr,
                                 const brw_reg &src, const brw_reg &offset_src,
                                 brw_reg urb_handle)
    {
       assert(nir_src_bit_size(instr->src[0]) == 32);
    
       const struct intel_device_info *devinfo = bld.shader->devinfo;
       const unsigned runit = reg_unit(devinfo);
       const unsigned write_size = 8 * runit;
    
       const unsigned comps = nir_src_num_components(instr->src[0]);
       assert(comps <= 4);
    
       const unsigned base_in_dwords = nir_intrinsic_base(instr) +
                                       component_from_intrinsic(instr);
    
       if (base_in_dwords > 0) {
          brw_builder bldall = bld.group(write_size, 0).exec_all();
          urb_handle = bldall.ADD(urb_handle, brw_imm_ud(base_in_dwords * 4));
       }
    
       const unsigned mask = nir_intrinsic_write_mask(instr);
    
       for (unsigned q = 0; q < bld.dispatch_width() / write_size; q++) {
          brw_builder wbld = bld.group(write_size, q);
    
          brw_reg payload_srcs[4];
    
          for (unsigned c = 0; c < comps; c++)
             payload_srcs[c] = horiz_offset(offset(src, bld, c), write_size * q);
    
          brw_reg addr =
             wbld.ADD(wbld.SHL(retype(horiz_offset(offset_src, write_size * q),
                                      BRW_TYPE_UD),
                               brw_imm_ud(2)), urb_handle);
    
          brw_reg srcs[URB_LOGICAL_NUM_SRCS];
          srcs[URB_LOGICAL_SRC_HANDLE] = addr;
          srcs[URB_LOGICAL_SRC_CHANNEL_MASK] = brw_imm_ud(mask << 16);
          int nr = bld.shader->alloc.allocate(comps * runit);
          srcs[URB_LOGICAL_SRC_DATA] = brw_vgrf(nr, BRW_TYPE_F);
          srcs[URB_LOGICAL_SRC_COMPONENTS] = brw_imm_ud(comps);
          wbld.LOAD_PAYLOAD(srcs[URB_LOGICAL_SRC_DATA], payload_srcs, comps, 0);
    
          wbld.emit(SHADER_OPCODE_URB_WRITE_LOGICAL,
                    reg_undef, srcs, ARRAY_SIZE(srcs));
       }
    }
    
    static void
    emit_urb_indirect_writes(const brw_builder &bld, nir_intrinsic_instr *instr,
                             const brw_reg &src, const brw_reg &offset_src,
                             brw_reg urb_handle)
    {
       assert(nir_src_bit_size(instr->src[0]) == 32);
    
       const unsigned comps = nir_src_num_components(instr->src[0]);
       assert(comps <= 4);
    
       const unsigned base_in_dwords = nir_intrinsic_base(instr) +
                                       component_from_intrinsic(instr);
    
       /* Use URB write message that allow different offsets per-slot.  The offset
        * is in units of vec4s (128 bits), so we use a write for each component,
        * replicating it in the sources and applying the appropriate mask based on
        * the dword offset.
        */
    
       for (unsigned c = 0; c < comps; c++) {
          if (((1 << c) & nir_intrinsic_write_mask(instr)) == 0)
             continue;
    
          brw_reg src_comp = offset(src, bld, c);
    
          for (unsigned q = 0; q < bld.dispatch_width() / 8; q++) {
             brw_builder bld8 = bld.group(8, q);
    
             /* offset is always positive, so signedness doesn't matter */
             assert(offset_src.type == BRW_TYPE_D ||
                    offset_src.type == BRW_TYPE_UD);
    
             brw_reg off =
                bld8.ADD(quarter(retype(offset_src, BRW_TYPE_UD), q),
                         brw_imm_ud(c + base_in_dwords));
             brw_reg m = bld8.AND(off, brw_imm_ud(0x3));
             brw_reg t = bld8.SHL(bld8.MOV(brw_imm_ud(1)), m);
             brw_reg mask = bld8.SHL(t, brw_imm_ud(16));
             brw_reg final_offset = bld8.SHR(off, brw_imm_ud(2));
    
             brw_reg payload_srcs[4];
             unsigned length = 0;
    
             for (unsigned j = 0; j < 4; j++)
                payload_srcs[length++] = quarter(src_comp, q);
    
             brw_reg srcs[URB_LOGICAL_NUM_SRCS];
             srcs[URB_LOGICAL_SRC_HANDLE] = urb_handle;
             srcs[URB_LOGICAL_SRC_PER_SLOT_OFFSETS] = final_offset;
             srcs[URB_LOGICAL_SRC_CHANNEL_MASK] = mask;
             srcs[URB_LOGICAL_SRC_DATA] = brw_vgrf(bld.shader->alloc.allocate(length),
                                                   BRW_TYPE_F);
             srcs[URB_LOGICAL_SRC_COMPONENTS] = brw_imm_ud(length);
             bld8.LOAD_PAYLOAD(srcs[URB_LOGICAL_SRC_DATA], payload_srcs, length, 0);
    
             fs_inst *inst = bld8.emit(SHADER_OPCODE_URB_WRITE_LOGICAL,
                                       reg_undef, srcs, ARRAY_SIZE(srcs));
             inst->offset = 0;
          }
       }
    }
    
    static void
    emit_urb_direct_reads(const brw_builder &bld, nir_intrinsic_instr *instr,
                          const brw_reg &dest, brw_reg urb_handle)
    {
       assert(instr->def.bit_size == 32);
    
       unsigned comps = instr->def.num_components;
       if (comps == 0)
          return;
    
       nir_src *offset_nir_src = nir_get_io_offset_src(instr);
       assert(nir_src_is_const(*offset_nir_src));
    
       const unsigned offset_in_dwords = nir_intrinsic_base(instr) +
                                         nir_src_as_uint(*offset_nir_src) +
                                         component_from_intrinsic(instr);
    
       unsigned urb_global_offset = offset_in_dwords / 4;
       adjust_handle_and_offset(bld, urb_handle, urb_global_offset);
    
       const unsigned comp_offset = offset_in_dwords % 4;
       const unsigned num_regs = comp_offset + comps;
    
       brw_builder ubld8 = bld.group(8, 0).exec_all();
       brw_reg data = ubld8.vgrf(BRW_TYPE_UD, num_regs);
       brw_reg srcs[URB_LOGICAL_NUM_SRCS];
       srcs[URB_LOGICAL_SRC_HANDLE] = urb_handle;
    
       fs_inst *inst = ubld8.emit(SHADER_OPCODE_URB_READ_LOGICAL, data,
                                  srcs, ARRAY_SIZE(srcs));
       inst->offset = urb_global_offset;
       assert(inst->offset < 2048);
       inst->size_written = num_regs * REG_SIZE;
    
       for (unsigned c = 0; c < comps; c++) {
          brw_reg dest_comp = offset(dest, bld, c);
          brw_reg data_comp = horiz_stride(offset(data, ubld8, comp_offset + c), 0);
          bld.MOV(retype(dest_comp, BRW_TYPE_UD), data_comp);
       }
    }
    
    static void
    emit_urb_direct_reads_xe2(const brw_builder &bld, nir_intrinsic_instr *instr,
                              const brw_reg &dest, brw_reg urb_handle)
    {
       assert(instr->def.bit_size == 32);
    
       unsigned comps = instr->def.num_components;
       if (comps == 0)
          return;
    
       nir_src *offset_nir_src = nir_get_io_offset_src(instr);
       assert(nir_src_is_const(*offset_nir_src));
    
       brw_builder ubld16 = bld.group(16, 0).exec_all();
    
       const unsigned offset_in_dwords = nir_intrinsic_base(instr) +
                                         nir_src_as_uint(*offset_nir_src) +
                                         component_from_intrinsic(instr);
    
       if (offset_in_dwords > 0)
          urb_handle = ubld16.ADD(urb_handle, brw_imm_ud(offset_in_dwords * 4));
    
       brw_reg data = ubld16.vgrf(BRW_TYPE_UD, comps);
       brw_reg srcs[URB_LOGICAL_NUM_SRCS];
       srcs[URB_LOGICAL_SRC_HANDLE] = urb_handle;
    
       fs_inst *inst = ubld16.emit(SHADER_OPCODE_URB_READ_LOGICAL,
                                   data, srcs, ARRAY_SIZE(srcs));
       inst->size_written = 2 * comps * REG_SIZE;
    
       for (unsigned c = 0; c < comps; c++) {
          brw_reg dest_comp = offset(dest, bld, c);
          brw_reg data_comp = horiz_stride(offset(data, ubld16, c), 0);
          bld.MOV(retype(dest_comp, BRW_TYPE_UD), data_comp);
       }
    }
    
    static void
    emit_urb_indirect_reads(const brw_builder &bld, nir_intrinsic_instr *instr,
                            const brw_reg &dest, const brw_reg &offset_src, brw_reg urb_handle)
    {
       assert(instr->def.bit_size == 32);
    
       unsigned comps = instr->def.num_components;
       if (comps == 0)
          return;
    
       brw_reg seq_ud;
       {
          brw_builder ubld8 = bld.group(8, 0).exec_all();
          seq_ud = ubld8.vgrf(BRW_TYPE_UD, 1);
          brw_reg seq_uw = ubld8.vgrf(BRW_TYPE_UW, 1);
          ubld8.MOV(seq_uw, brw_reg(brw_imm_v(0x76543210)));
          ubld8.MOV(seq_ud, seq_uw);
          seq_ud = ubld8.SHL(seq_ud, brw_imm_ud(2));
       }
    
       const unsigned base_in_dwords = nir_intrinsic_base(instr) +
                                       component_from_intrinsic(instr);
    
       for (unsigned c = 0; c < comps; c++) {
          for (unsigned q = 0; q < bld.dispatch_width() / 8; q++) {
             brw_builder bld8 = bld.group(8, q);
    
             /* offset is always positive, so signedness doesn't matter */
             assert(offset_src.type == BRW_TYPE_D ||
                    offset_src.type == BRW_TYPE_UD);
             brw_reg off =
                bld8.ADD(bld8.MOV(quarter(retype(offset_src, BRW_TYPE_UD), q)),
                         brw_imm_ud(base_in_dwords + c));
    
             STATIC_ASSERT(IS_POT(REG_SIZE) && REG_SIZE > 1);
    
             brw_reg comp;
             comp = bld8.AND(off, brw_imm_ud(0x3));
             comp = bld8.SHL(comp, brw_imm_ud(ffs(REG_SIZE) - 1));
             comp = bld8.ADD(comp, seq_ud);
    
             off = bld8.SHR(off, brw_imm_ud(2));
    
             brw_reg srcs[URB_LOGICAL_NUM_SRCS];
             srcs[URB_LOGICAL_SRC_HANDLE] = urb_handle;
             srcs[URB_LOGICAL_SRC_PER_SLOT_OFFSETS] = off;
    
             brw_reg data = bld8.vgrf(BRW_TYPE_UD, 4);
    
             fs_inst *inst = bld8.emit(SHADER_OPCODE_URB_READ_LOGICAL,
                                       data, srcs, ARRAY_SIZE(srcs));
             inst->offset = 0;
             inst->size_written = 4 * REG_SIZE;
    
             brw_reg dest_comp = offset(dest, bld, c);
             bld8.emit(SHADER_OPCODE_MOV_INDIRECT,
                       retype(quarter(dest_comp, q), BRW_TYPE_UD),
                       data,
                       comp,
                       brw_imm_ud(4 * REG_SIZE));
          }
       }
    }
    
    static void
    emit_urb_indirect_reads_xe2(const brw_builder &bld, nir_intrinsic_instr *instr,
                                const brw_reg &dest, const brw_reg &offset_src,
                                brw_reg urb_handle)
    {
       assert(instr->def.bit_size == 32);
    
       unsigned comps = instr->def.num_components;
       if (comps == 0)
          return;
    
       brw_builder ubld16 = bld.group(16, 0).exec_all();
    
       const unsigned offset_in_dwords = nir_intrinsic_base(instr) +
                                         component_from_intrinsic(instr);
    
       if (offset_in_dwords > 0)
          urb_handle = ubld16.ADD(urb_handle, brw_imm_ud(offset_in_dwords * 4));
    
       brw_reg data = ubld16.vgrf(BRW_TYPE_UD, comps);
    
       for (unsigned q = 0; q < bld.dispatch_width() / 16; q++) {
          brw_builder wbld = bld.group(16, q);
    
          brw_reg addr = wbld.SHL(retype(horiz_offset(offset_src, 16 * q),
                                         BRW_TYPE_UD),
                                  brw_imm_ud(2));
    
          brw_reg srcs[URB_LOGICAL_NUM_SRCS];
          srcs[URB_LOGICAL_SRC_HANDLE] = wbld.ADD(addr, urb_handle);
    
          fs_inst *inst = wbld.emit(SHADER_OPCODE_URB_READ_LOGICAL,
                                     data, srcs, ARRAY_SIZE(srcs));
          inst->size_written = 2 * comps * REG_SIZE;
    
          for (unsigned c = 0; c < comps; c++) {
             brw_reg dest_comp = horiz_offset(offset(dest, bld, c), 16 * q);
             brw_reg data_comp = offset(data, wbld, c);
             wbld.MOV(retype(dest_comp, BRW_TYPE_UD), data_comp);
          }
       }
    }
    
    static void
    emit_task_mesh_store(nir_to_brw_state &ntb,
                         const brw_builder &bld, nir_intrinsic_instr *instr,
                         const brw_reg &urb_handle)
    {
       brw_reg src = get_nir_src(ntb, instr->src[0], -1);
       nir_src *offset_nir_src = nir_get_io_offset_src(instr);
    
       if (nir_src_is_const(*offset_nir_src)) {
          if (bld.shader->devinfo->ver >= 20)
             emit_urb_direct_writes_xe2(bld, instr, src, urb_handle);
          else
             emit_urb_direct_writes(bld, instr, src, urb_handle);
       } else {
          if (bld.shader->devinfo->ver >= 20) {
             emit_urb_indirect_writes_xe2(bld, instr, src, get_nir_src(ntb, *offset_nir_src), urb_handle);
             return;
          }
          bool use_mod = false;
          unsigned mod;
    
          /* Try to calculate the value of (offset + base) % 4. If we can do
           * this, then we can do indirect writes using only 1 URB write.
           */
          use_mod = nir_mod_analysis(nir_get_scalar(offset_nir_src->ssa, 0), nir_type_uint, 4, &mod);
          if (use_mod) {
             mod += nir_intrinsic_base(instr) + component_from_intrinsic(instr);
             mod %= 4;
          }
    
          if (use_mod) {
             emit_urb_indirect_writes_mod(bld, instr, src, get_nir_src(ntb, *offset_nir_src), urb_handle, mod);
          } else {
             emit_urb_indirect_writes(bld, instr, src, get_nir_src(ntb, *offset_nir_src), urb_handle);
          }
       }
    }
    
    static void
    emit_task_mesh_load(nir_to_brw_state &ntb,
                        const brw_builder &bld, nir_intrinsic_instr *instr,
                        const brw_reg &urb_handle)
    {
       brw_reg dest = get_nir_def(ntb, instr->def);
       nir_src *offset_nir_src = nir_get_io_offset_src(instr);
    
       /* TODO(mesh): for per_vertex and per_primitive, if we could keep around
        * the non-array-index offset, we could use to decide if we can perform
        * a single large aligned read instead one per component.
        */
    
       if (nir_src_is_const(*offset_nir_src)) {
          if (bld.shader->devinfo->ver >= 20)
             emit_urb_direct_reads_xe2(bld, instr, dest, urb_handle);
          else
             emit_urb_direct_reads(bld, instr, dest, urb_handle);
       } else {
          if (bld.shader->devinfo->ver >= 20)
             emit_urb_indirect_reads_xe2(bld, instr, dest, get_nir_src(ntb, *offset_nir_src), urb_handle);
          else
             emit_urb_indirect_reads(bld, instr, dest, get_nir_src(ntb, *offset_nir_src), urb_handle);
       }
    }
    
    static void
    fs_nir_emit_task_mesh_intrinsic(nir_to_brw_state &ntb, const brw_builder &bld,
                                    nir_intrinsic_instr *instr)
    {
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_MESH || s.stage == MESA_SHADER_TASK);
       const task_mesh_thread_payload &payload = s.task_mesh_payload();
    
       brw_reg dest;
       if (nir_intrinsic_infos[instr->intrinsic].has_dest)
          dest = get_nir_def(ntb, instr->def);
    
       switch (instr->intrinsic) {
       case nir_intrinsic_load_draw_id:
          dest = retype(dest, BRW_TYPE_UD);
          bld.MOV(dest, payload.extended_parameter_0);
          break;
    
       case nir_intrinsic_load_local_invocation_id:
          unreachable("local invocation id should have been lowered earlier");
          break;
    
       case nir_intrinsic_load_local_invocation_index:
          dest = retype(dest, BRW_TYPE_UD);
          bld.MOV(dest, payload.local_index);
          break;
    
       case nir_intrinsic_load_num_workgroups:
          dest = retype(dest, BRW_TYPE_UD);
          bld.MOV(offset(dest, bld, 0), brw_uw1_grf(0, 13)); /* g0.6 >> 16 */
          bld.MOV(offset(dest, bld, 1), brw_uw1_grf(0, 8));  /* g0.4 & 0xffff */
          bld.MOV(offset(dest, bld, 2), brw_uw1_grf(0, 9));  /* g0.4 >> 16 */
          break;
    
       case nir_intrinsic_load_workgroup_index:
          dest = retype(dest, BRW_TYPE_UD);
          bld.MOV(dest, retype(brw_vec1_grf(0, 1), BRW_TYPE_UD));
          break;
    
       default:
          fs_nir_emit_cs_intrinsic(ntb, instr);
          break;
       }
    }
    
    static void
    fs_nir_emit_task_intrinsic(nir_to_brw_state &ntb,
                               nir_intrinsic_instr *instr)
    {
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_TASK);
       const task_mesh_thread_payload &payload = s.task_mesh_payload();
    
       switch (instr->intrinsic) {
       case nir_intrinsic_store_output:
       case nir_intrinsic_store_task_payload:
          emit_task_mesh_store(ntb, bld, instr, payload.urb_output);
          break;
    
       case nir_intrinsic_load_output:
       case nir_intrinsic_load_task_payload:
          emit_task_mesh_load(ntb, bld, instr, payload.urb_output);
          break;
    
       default:
          fs_nir_emit_task_mesh_intrinsic(ntb, bld, instr);
          break;
       }
    }
    
    static void
    fs_nir_emit_mesh_intrinsic(nir_to_brw_state &ntb,
                               nir_intrinsic_instr *instr)
    {
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       assert(s.stage == MESA_SHADER_MESH);
       const task_mesh_thread_payload &payload = s.task_mesh_payload();
    
       switch (instr->intrinsic) {
       case nir_intrinsic_store_per_primitive_output:
       case nir_intrinsic_store_per_vertex_output:
       case nir_intrinsic_store_output:
          emit_task_mesh_store(ntb, bld, instr, payload.urb_output);
          break;
    
       case nir_intrinsic_load_per_vertex_output:
       case nir_intrinsic_load_per_primitive_output:
       case nir_intrinsic_load_output:
          emit_task_mesh_load(ntb, bld, instr, payload.urb_output);
          break;
    
       case nir_intrinsic_load_task_payload:
          emit_task_mesh_load(ntb, bld, instr, payload.task_urb_input);
          break;
    
       default:
          fs_nir_emit_task_mesh_intrinsic(ntb, bld, instr);
          break;
       }
    }
    
    static void
    fs_nir_emit_intrinsic(nir_to_brw_state &ntb,
                          const brw_builder &bld, nir_intrinsic_instr *instr)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       fs_visitor &s = ntb.s;
    
       /* We handle this as a special case */
       if (instr->intrinsic == nir_intrinsic_decl_reg) {
          assert(nir_intrinsic_num_array_elems(instr) == 0);
          unsigned bit_size = nir_intrinsic_bit_size(instr);
          unsigned num_components = nir_intrinsic_num_components(instr);
          const brw_reg_type reg_type =
             brw_type_with_size(bit_size == 8 ? BRW_TYPE_D : BRW_TYPE_F,
                                bit_size);
    
          /* Re-use the destination's slot in the table for the register */
          ntb.ssa_values[instr->def.index] =
             bld.vgrf(reg_type, num_components);
          return;
       }
    
       brw_reg dest;
       if (nir_intrinsic_infos[instr->intrinsic].has_dest)
          dest = get_nir_def(ntb, instr->def);
    
       const brw_builder xbld = dest.is_scalar ? bld.scalar_group() : bld;
    
       switch (instr->intrinsic) {
       case nir_intrinsic_resource_intel: {
          ntb.ssa_bind_infos[instr->def.index].valid = true;
          ntb.ssa_bind_infos[instr->def.index].bindless =
             (nir_intrinsic_resource_access_intel(instr) &
              nir_resource_intel_bindless) != 0;
          ntb.ssa_bind_infos[instr->def.index].block =
             nir_intrinsic_resource_block_intel(instr);
          ntb.ssa_bind_infos[instr->def.index].set =
             nir_intrinsic_desc_set(instr);
          ntb.ssa_bind_infos[instr->def.index].binding =
             nir_intrinsic_binding(instr);
    
          dest = retype(dest, BRW_TYPE_UD);
          ntb.ssa_values[instr->def.index] = dest;
    
          xbld.MOV(dest,
                   bld.emit_uniformize(get_nir_src(ntb, instr->src[1])));
          break;
       }
    
       case nir_intrinsic_load_reg:
       case nir_intrinsic_store_reg:
          /* Nothing to do with these. */
          break;
    
       case nir_intrinsic_load_global_constant_uniform_block_intel:
       case nir_intrinsic_load_ssbo_uniform_block_intel:
       case nir_intrinsic_load_shared_uniform_block_intel:
       case nir_intrinsic_load_global_block_intel:
       case nir_intrinsic_store_global_block_intel:
       case nir_intrinsic_load_shared_block_intel:
       case nir_intrinsic_store_shared_block_intel:
       case nir_intrinsic_load_ssbo_block_intel:
       case nir_intrinsic_store_ssbo_block_intel:
       case nir_intrinsic_image_load:
       case nir_intrinsic_image_store:
       case nir_intrinsic_image_atomic:
       case nir_intrinsic_image_atomic_swap:
       case nir_intrinsic_bindless_image_load:
       case nir_intrinsic_bindless_image_store:
       case nir_intrinsic_bindless_image_atomic:
       case nir_intrinsic_bindless_image_atomic_swap:
       case nir_intrinsic_load_shared:
       case nir_intrinsic_store_shared:
       case nir_intrinsic_shared_atomic:
       case nir_intrinsic_shared_atomic_swap:
       case nir_intrinsic_load_ssbo:
       case nir_intrinsic_store_ssbo:
       case nir_intrinsic_ssbo_atomic:
       case nir_intrinsic_ssbo_atomic_swap:
       case nir_intrinsic_load_global:
       case nir_intrinsic_load_global_constant:
       case nir_intrinsic_store_global:
       case nir_intrinsic_global_atomic:
       case nir_intrinsic_global_atomic_swap:
       case nir_intrinsic_load_scratch:
       case nir_intrinsic_store_scratch:
          fs_nir_emit_memory_access(ntb, bld, xbld, instr);
          break;
    
       case nir_intrinsic_image_size:
       case nir_intrinsic_bindless_image_size: {
          /* Cube image sizes should have previously been lowered to a 2D array */
          assert(nir_intrinsic_image_dim(instr) != GLSL_SAMPLER_DIM_CUBE);
    
          /* Unlike the [un]typed load and store opcodes, the TXS that this turns
           * into will handle the binding table index for us in the geneerator.
           * Incidentally, this means that we can handle bindless with exactly the
           * same code.
           */
          brw_reg image = retype(get_nir_src_imm(ntb, instr->src[0]), BRW_TYPE_UD);
          image = bld.emit_uniformize(image);
    
          assert(nir_src_as_uint(instr->src[1]) == 0);
    
          brw_reg srcs[TEX_LOGICAL_NUM_SRCS];
          if (instr->intrinsic == nir_intrinsic_image_size)
             srcs[TEX_LOGICAL_SRC_SURFACE] = image;
          else
             srcs[TEX_LOGICAL_SRC_SURFACE_HANDLE] = image;
          srcs[TEX_LOGICAL_SRC_SAMPLER] = brw_imm_d(0);
          srcs[TEX_LOGICAL_SRC_COORD_COMPONENTS] = brw_imm_d(0);
          srcs[TEX_LOGICAL_SRC_GRAD_COMPONENTS] = brw_imm_d(0);
          srcs[TEX_LOGICAL_SRC_RESIDENCY] = brw_imm_d(0);
    
          /* Since the image size is always uniform, we can just emit a SIMD8
           * query instruction and splat the result out.
           */
          const brw_builder ubld = bld.scalar_group();
    
          brw_reg tmp = ubld.vgrf(BRW_TYPE_UD, 4);
          fs_inst *inst = ubld.emit(SHADER_OPCODE_IMAGE_SIZE_LOGICAL,
                                    tmp, srcs, ARRAY_SIZE(srcs));
          inst->size_written = 4 * REG_SIZE * reg_unit(devinfo);
    
          for (unsigned c = 0; c < instr->def.num_components; ++c) {
             bld.MOV(offset(retype(dest, tmp.type), bld, c),
                     component(offset(tmp, ubld, c), 0));
          }
          break;
       }
    
       case nir_intrinsic_barrier:
       case nir_intrinsic_begin_invocation_interlock:
       case nir_intrinsic_end_invocation_interlock: {
          bool ugm_fence, slm_fence, tgm_fence, urb_fence;
          enum opcode opcode = BRW_OPCODE_NOP;
    
          /* Handling interlock intrinsics here will allow the logic for IVB
           * render cache (see below) to be reused.
           */
    
          switch (instr->intrinsic) {
          case nir_intrinsic_barrier: {
             /* Note we only care about the memory part of the
              * barrier.  The execution part will be taken care
              * of by the stage specific intrinsic handler functions.
              */
             nir_variable_mode modes = nir_intrinsic_memory_modes(instr);
             ugm_fence = modes & (nir_var_mem_ssbo | nir_var_mem_global);
             slm_fence = modes & nir_var_mem_shared;
             tgm_fence = modes & nir_var_image;
             urb_fence = modes & (nir_var_shader_out | nir_var_mem_task_payload);
             if (nir_intrinsic_memory_scope(instr) != SCOPE_NONE)
                opcode = SHADER_OPCODE_MEMORY_FENCE;
             break;
          }
    
          case nir_intrinsic_begin_invocation_interlock:
             /* For beginInvocationInterlockARB(), we will generate a memory fence
              * but with a different opcode so that generator can pick SENDC
              * instead of SEND.
              */
             assert(s.stage == MESA_SHADER_FRAGMENT);
             ugm_fence = tgm_fence = true;
             slm_fence = urb_fence = false;
             opcode = SHADER_OPCODE_INTERLOCK;
             break;
    
          case nir_intrinsic_end_invocation_interlock:
             /* For endInvocationInterlockARB(), we need to insert a memory fence which
              * stalls in the shader until the memory transactions prior to that
              * fence are complete.  This ensures that the shader does not end before
              * any writes from its critical section have landed.  Otherwise, you can
              * end up with a case where the next invocation on that pixel properly
              * stalls for previous FS invocation on its pixel to complete but
              * doesn't actually wait for the dataport memory transactions from that
              * thread to land before submitting its own.
              */
             assert(s.stage == MESA_SHADER_FRAGMENT);
             ugm_fence = tgm_fence = true;
             slm_fence = urb_fence = false;
             opcode = SHADER_OPCODE_MEMORY_FENCE;
             break;
    
          default:
             unreachable("invalid intrinsic");
          }
    
          if (opcode == BRW_OPCODE_NOP)
             break;
    
          if (s.nir->info.shared_size > 0) {
             assert(gl_shader_stage_uses_workgroup(s.stage));
          } else {
             slm_fence = false;
          }
    
          /* If the workgroup fits in a single HW thread, the messages for SLM are
           * processed in-order and the shader itself is already synchronized so
           * the memory fence is not necessary.
           *
           * TODO: Check if applies for many HW threads sharing same Data Port.
           */
          if (!s.nir->info.workgroup_size_variable &&
              slm_fence && brw_workgroup_size(s) <= s.dispatch_width)
             slm_fence = false;
    
          switch (s.stage) {
             case MESA_SHADER_TESS_CTRL:
             case MESA_SHADER_TASK:
             case MESA_SHADER_MESH:
                break;
             default:
                urb_fence = false;
                break;
          }
    
          unsigned fence_regs_count = 0;
          brw_reg fence_regs[4] = {};
    
          const brw_builder ubld = bld.group(8, 0);
    
          /* A memory barrier with acquire semantics requires us to
           * guarantee that memory operations of the specified storage
           * class sequenced-after the barrier aren't reordered before the
           * barrier, nor before any previous atomic operation
           * sequenced-before the barrier which may be synchronizing this
           * acquire barrier with a prior release sequence.
           *
           * In order to guarantee the latter we must make sure that any
           * such previous operation has completed execution before
           * invalidating the relevant caches, since otherwise some cache
           * could be polluted by a concurrent thread after its
           * invalidation but before the previous atomic completes, which
           * could lead to a violation of the expected memory ordering if
           * a subsequent memory read hits the polluted cacheline, which
           * would return a stale value read from memory before the
           * completion of the atomic sequenced-before the barrier.
           *
           * This ordering inversion can be avoided trivially if the
           * operations we need to order are all handled by a single
           * in-order cache, since the flush implied by the memory fence
           * occurs after any pending operations have completed, however
           * that doesn't help us when dealing with multiple caches
           * processing requests out of order, in which case we need to
           * explicitly stall the EU until any pending memory operations
           * have executed.
           *
           * Note that that might be somewhat heavy handed in some cases.
           * In particular when this memory fence was inserted by
           * spirv_to_nir() lowering an atomic with acquire semantics into
           * an atomic+barrier sequence we could do a better job by
           * synchronizing with respect to that one atomic *only*, but
           * that would require additional information not currently
           * available to the backend.
           *
           * XXX - Use an alternative workaround on IVB and ICL, since
           *       SYNC.ALLWR is only available on Gfx12+.
           */
          if (devinfo->ver >= 12 &&
              (!nir_intrinsic_has_memory_scope(instr) ||
               (nir_intrinsic_memory_semantics(instr) & NIR_MEMORY_ACQUIRE))) {
             ubld.exec_all().group(1, 0).SYNC(TGL_SYNC_ALLWR);
          }
    
          if (devinfo->has_lsc) {
             assert(devinfo->verx10 >= 125);
             uint32_t desc =
                lsc_fence_descriptor_for_intrinsic(devinfo, instr);
             if (ugm_fence) {
                fence_regs[fence_regs_count++] =
                   emit_fence(ubld, opcode, GFX12_SFID_UGM, desc,
                              true /* commit_enable */,
                              0 /* bti; ignored for LSC */);
             }
    
             if (tgm_fence) {
                fence_regs[fence_regs_count++] =
                   emit_fence(ubld, opcode, GFX12_SFID_TGM, desc,
                              true /* commit_enable */,
                              0 /* bti; ignored for LSC */);
             }
    
             if (slm_fence) {
                assert(opcode == SHADER_OPCODE_MEMORY_FENCE);
                if (intel_needs_workaround(devinfo, 14014063774)) {
                   /* Wa_14014063774
                    *
                    * Before SLM fence compiler needs to insert SYNC.ALLWR in order
                    * to avoid the SLM data race.
                    */
                   ubld.exec_all().group(1, 0).SYNC(TGL_SYNC_ALLWR);
                }
                fence_regs[fence_regs_count++] =
                   emit_fence(ubld, opcode, GFX12_SFID_SLM, desc,
                              true /* commit_enable */,
                              0 /* BTI; ignored for LSC */);
             }
    
             if (urb_fence) {
                assert(opcode == SHADER_OPCODE_MEMORY_FENCE);
                fence_regs[fence_regs_count++] =
                   emit_fence(ubld, opcode, BRW_SFID_URB, desc,
                              true /* commit_enable */,
                              0 /* BTI; ignored for LSC */);
             }
          } else if (devinfo->ver >= 11) {
             if (tgm_fence || ugm_fence || urb_fence) {
                fence_regs[fence_regs_count++] =
                   emit_fence(ubld, opcode, GFX7_SFID_DATAPORT_DATA_CACHE, 0,
                              true /* commit_enable HSD ES # 1404612949 */,
                              0 /* BTI = 0 means data cache */);
             }
    
             if (slm_fence) {
                assert(opcode == SHADER_OPCODE_MEMORY_FENCE);
                fence_regs[fence_regs_count++] =
                   emit_fence(ubld, opcode, GFX7_SFID_DATAPORT_DATA_CACHE, 0,
                              true /* commit_enable HSD ES # 1404612949 */,
                              GFX7_BTI_SLM);
             }
          } else {
             /* Simulation also complains on Gfx9 if we do not enable commit.
              */
             const bool commit_enable =
                instr->intrinsic == nir_intrinsic_end_invocation_interlock ||
                devinfo->ver == 9;
    
             if (tgm_fence || ugm_fence || slm_fence || urb_fence) {
                fence_regs[fence_regs_count++] =
                   emit_fence(ubld, opcode, GFX7_SFID_DATAPORT_DATA_CACHE, 0,
                              commit_enable, 0 /* BTI */);
             }
          }
    
          assert(fence_regs_count <= ARRAY_SIZE(fence_regs));
    
          /* Be conservative in Gen11+ and always stall in a fence.  Since
           * there are two different fences, and shader might want to
           * synchronize between them.
           *
           * TODO: Use scope and visibility information for the barriers from NIR
           * to make a better decision on whether we need to stall.
           */
          bool force_stall = devinfo->ver >= 11;
    
          /* There are four cases where we want to insert a stall:
           *
           *  1. If we're a nir_intrinsic_end_invocation_interlock.  This is
           *     required to ensure that the shader EOT doesn't happen until
           *     after the fence returns.  Otherwise, we might end up with the
           *     next shader invocation for that pixel not respecting our fence
           *     because it may happen on a different HW thread.
           *
           *  2. If we have multiple fences.  This is required to ensure that
           *     they all complete and nothing gets weirdly out-of-order.
           *
           *  3. If we have no fences.  In this case, we need at least a
           *     scheduling barrier to keep the compiler from moving things
           *     around in an invalid way.
           *
           *  4. On Gen11+ and platforms with LSC, we have multiple fence types,
           *     without further information about the fence, we need to force a
           *     stall.
           */
          if (instr->intrinsic == nir_intrinsic_end_invocation_interlock ||
              fence_regs_count != 1 || devinfo->has_lsc || force_stall) {
             ubld.exec_all().group(1, 0).emit(
                FS_OPCODE_SCHEDULING_FENCE, ubld.null_reg_ud(),
                fence_regs, fence_regs_count);
          }
    
          break;
       }
    
       case nir_intrinsic_shader_clock: {
          /* We cannot do anything if there is an event, so ignore it for now */
          const brw_reg shader_clock = get_timestamp(bld);
          const brw_reg srcs[] = { component(shader_clock, 0),
                                  component(shader_clock, 1) };
          bld.LOAD_PAYLOAD(dest, srcs, ARRAY_SIZE(srcs), 0);
          break;
       }
    
       case nir_intrinsic_load_reloc_const_intel: {
          uint32_t id = nir_intrinsic_param_idx(instr);
          uint32_t base = nir_intrinsic_base(instr);
    
          assert(dest.is_scalar);
    
          xbld.emit(SHADER_OPCODE_MOV_RELOC_IMM, retype(dest, BRW_TYPE_D),
                    brw_imm_ud(id), brw_imm_ud(base));
          break;
       }
    
       case nir_intrinsic_load_uniform:
       case nir_intrinsic_load_push_constant: {
          /* Offsets are in bytes but they should always aligned to
           * the type size
           */
          unsigned base_offset = nir_intrinsic_base(instr);
          assert(base_offset % 4 == 0 || base_offset % brw_type_size_bytes(dest.type) == 0);
    
          brw_reg src = brw_uniform_reg(base_offset / 4, dest.type);
    
          if (nir_src_is_const(instr->src[0])) {
             unsigned load_offset = nir_src_as_uint(instr->src[0]);
             assert(load_offset % brw_type_size_bytes(dest.type) == 0);
             /* The base offset can only handle 32-bit units, so for 16-bit
              * data take the modulo of the offset with 4 bytes and add it to
              * the offset to read from within the source register.
              */
             src.offset = load_offset + base_offset % 4;
    
             for (unsigned j = 0; j < instr->num_components; j++) {
                xbld.MOV(offset(dest, xbld, j), offset(src, xbld, j));
             }
          } else {
             brw_reg indirect = retype(get_nir_src(ntb, instr->src[0]),
                                      BRW_TYPE_UD);
    
             /* We need to pass a size to the MOV_INDIRECT but we don't want it to
              * go past the end of the uniform.  In order to keep the n'th
              * component from running past, we subtract off the size of all but
              * one component of the vector.
              */
             assert(nir_intrinsic_range(instr) >=
                    instr->num_components * brw_type_size_bytes(dest.type));
             unsigned read_size = nir_intrinsic_range(instr) -
                (instr->num_components - 1) * brw_type_size_bytes(dest.type);
    
             bool supports_64bit_indirects = !intel_device_info_is_9lp(devinfo);
    
             if (brw_type_size_bytes(dest.type) != 8 || supports_64bit_indirects) {
                for (unsigned j = 0; j < instr->num_components; j++) {
                   xbld.emit(SHADER_OPCODE_MOV_INDIRECT,
                             offset(dest, xbld, j), offset(src, xbld, j),
                             indirect, brw_imm_ud(read_size));
                }
             } else {
                const unsigned num_mov_indirects =
                   brw_type_size_bytes(dest.type) / brw_type_size_bytes(BRW_TYPE_UD);
                /* We read a little bit less per MOV INDIRECT, as they are now
                 * 32-bits ones instead of 64-bit. Fix read_size then.
                 */
                const unsigned read_size_32bit = read_size -
                    (num_mov_indirects - 1) * brw_type_size_bytes(BRW_TYPE_UD);
                for (unsigned j = 0; j < instr->num_components; j++) {
                   for (unsigned i = 0; i < num_mov_indirects; i++) {
                      xbld.emit(SHADER_OPCODE_MOV_INDIRECT,
                                subscript(offset(dest, xbld, j), BRW_TYPE_UD, i),
                                subscript(offset(src, xbld, j), BRW_TYPE_UD, i),
                                indirect, brw_imm_ud(read_size_32bit));
                   }
                }
             }
          }
          break;
       }
    
       case nir_intrinsic_load_ubo:
       case nir_intrinsic_load_ubo_uniform_block_intel: {
          brw_reg surface, surface_handle;
          bool no_mask_handle = false;
    
          if (get_nir_src_bindless(ntb, instr->src[0]))
             surface_handle = get_nir_buffer_intrinsic_index(ntb, bld, instr, &no_mask_handle);
          else
             surface = get_nir_buffer_intrinsic_index(ntb, bld, instr, &no_mask_handle);
    
          const unsigned first_component =
             nir_def_first_component_read(&instr->def);
          const unsigned last_component =
             nir_def_last_component_read(&instr->def);
          const unsigned num_components = last_component - first_component + 1;
    
          if (!nir_src_is_const(instr->src[1])) {
             s.prog_data->has_ubo_pull = true;
    
             if (instr->intrinsic == nir_intrinsic_load_ubo) {
                /* load_ubo with non-constant offset. The offset might still be
                 * uniform on non-LSC platforms when loading fewer than 4
                 * components.
                 */
                brw_reg base_offset = retype(get_nir_src(ntb, instr->src[1]),
                                            BRW_TYPE_UD);
    
                const unsigned comps_per_load = brw_type_size_bytes(dest.type) == 8 ? 2 : 4;
    
                for (unsigned i = first_component;
                     i <= last_component;
                     i += comps_per_load) {
                   const unsigned remaining = last_component + 1 - i;
                   xbld.VARYING_PULL_CONSTANT_LOAD(offset(dest, xbld, i),
                                                   surface, surface_handle,
                                                   base_offset,
                                                   i * brw_type_size_bytes(dest.type),
                                                   instr->def.bit_size / 8,
                                                   MIN2(remaining, comps_per_load));
                }
             } else {
                /* load_ubo_uniform_block_intel with non-constant offset */
                fs_nir_emit_memory_access(ntb, bld, xbld, instr);
             }
          } else {
             /* Even if we are loading doubles, a pull constant load will load
              * a 32-bit vec4, so should only reserve vgrf space for that. If we
              * need to load a full dvec4 we will have to emit 2 loads. This is
              * similar to demote_pull_constants(), except that in that case we
              * see individual accesses to each component of the vector and then
              * we let CSE deal with duplicate loads. Here we see a vector access
              * and we have to split it if necessary.
              */
             const unsigned type_size = brw_type_size_bytes(dest.type);
             const unsigned load_offset =
                nir_src_as_uint(instr->src[1]) + first_component * type_size;
             const unsigned end_offset = load_offset + num_components * type_size;
             const unsigned ubo_block =
                brw_nir_ubo_surface_index_get_push_block(instr->src[0]);
             const unsigned offset_256b = load_offset / 32;
             const unsigned end_256b = DIV_ROUND_UP(end_offset, 32);
    
             /* See if we've selected this as a push constant candidate */
             brw_reg push_reg;
             for (int i = 0; i < 4; i++) {
                const struct brw_ubo_range *range = &s.prog_data->ubo_ranges[i];
                if (range->block == ubo_block &&
                    offset_256b >= range->start &&
                    end_256b <= range->start + range->length) {
    
                   push_reg = brw_uniform_reg(UBO_START + i, dest.type);
                   push_reg.offset = load_offset - 32 * range->start;
                   break;
                }
             }
    
             if (push_reg.file != BAD_FILE) {
                for (unsigned i = first_component; i <= last_component; i++) {
                   xbld.MOV(offset(dest, xbld, i),
                            byte_offset(push_reg,
                                        (i - first_component) * type_size));
                }
                break;
             }
    
             s.prog_data->has_ubo_pull = true;
    
             if (instr->intrinsic == nir_intrinsic_load_ubo_uniform_block_intel) {
                fs_nir_emit_memory_access(ntb, bld, xbld, instr);
                break;
             }
    
             const unsigned block_sz = 64; /* Fetch one cacheline at a time. */
             const brw_builder ubld = bld.exec_all().group(block_sz / 4, 0);
    
             for (unsigned c = 0; c < num_components;) {
                const unsigned base = load_offset + c * type_size;
                /* Number of usable components in the next block-aligned load. */
                const unsigned count = MIN2(num_components - c,
                                            (block_sz - base % block_sz) / type_size);
    
                const brw_reg packed_consts = ubld.vgrf(BRW_TYPE_UD);
                brw_reg srcs[PULL_UNIFORM_CONSTANT_SRCS];
                srcs[PULL_UNIFORM_CONSTANT_SRC_SURFACE]        = surface;
                srcs[PULL_UNIFORM_CONSTANT_SRC_SURFACE_HANDLE] = surface_handle;
                srcs[PULL_UNIFORM_CONSTANT_SRC_OFFSET]         = brw_imm_ud(base & ~(block_sz - 1));
                srcs[PULL_UNIFORM_CONSTANT_SRC_SIZE]           = brw_imm_ud(block_sz);
    
                ubld.emit(FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD, packed_consts,
                          srcs, PULL_UNIFORM_CONSTANT_SRCS);
    
                const brw_reg consts =
                   retype(byte_offset(packed_consts, base & (block_sz - 1)),
                          dest.type);
    
                for (unsigned d = 0; d < count; d++) {
                   xbld.MOV(offset(dest, xbld, first_component + c + d),
                            component(consts, d));
                }
    
                c += count;
             }
          }
          break;
       }
    
       case nir_intrinsic_store_output: {
          assert(nir_src_bit_size(instr->src[0]) == 32);
          brw_reg src = get_nir_src(ntb, instr->src[0], -1);
    
          unsigned store_offset = nir_src_as_uint(instr->src[1]);
          unsigned num_components = instr->num_components;
          unsigned first_component = nir_intrinsic_component(instr);
    
          brw_reg new_dest = retype(offset(s.outputs[instr->const_index[0]], bld,
                                          4 * store_offset), src.type);
    
          brw_combine_with_vec(bld, offset(new_dest, bld, first_component),
                               src, num_components);
          break;
       }
    
       case nir_intrinsic_get_ssbo_size: {
          assert(nir_src_num_components(instr->src[0]) == 1);
    
          /* A resinfo's sampler message is used to get the buffer size.  The
           * SIMD8's writeback message consists of four registers and SIMD16's
           * writeback message consists of 8 destination registers (two per each
           * component).  Because we are only interested on the first channel of
           * the first returned component, where resinfo returns the buffer size
           * for SURFTYPE_BUFFER, we can just use the SIMD8 variant regardless of
           * the dispatch width.
           */
          const brw_builder ubld = bld.scalar_group();
          brw_reg ret_payload = ubld.vgrf(BRW_TYPE_UD, 4);
    
          /* Set LOD = 0 */
          brw_reg src_payload = ubld.MOV(brw_imm_ud(0));
    
          brw_reg srcs[GET_BUFFER_SIZE_SRCS];
          srcs[get_nir_src_bindless(ntb, instr->src[0]) ?
               GET_BUFFER_SIZE_SRC_SURFACE_HANDLE :
               GET_BUFFER_SIZE_SRC_SURFACE] =
             get_nir_buffer_intrinsic_index(ntb, bld, instr);
          srcs[GET_BUFFER_SIZE_SRC_LOD] = src_payload;
          fs_inst *inst = ubld.emit(SHADER_OPCODE_GET_BUFFER_SIZE, ret_payload,
                                    srcs, GET_BUFFER_SIZE_SRCS);
          inst->header_size = 0;
          inst->mlen = reg_unit(devinfo);
          inst->size_written = 4 * REG_SIZE * reg_unit(devinfo);
    
          /* SKL PRM, vol07, 3D Media GPGPU Engine, Bounds Checking and Faulting:
           *
           * "Out-of-bounds checking is always performed at a DWord granularity. If
           * any part of the DWord is out-of-bounds then the whole DWord is
           * considered out-of-bounds."
           *
           * This implies that types with size smaller than 4-bytes need to be
           * padded if they don't complete the last dword of the buffer. But as we
           * need to maintain the original size we need to reverse the padding
           * calculation to return the correct size to know the number of elements
           * of an unsized array. As we stored in the last two bits of the surface
           * size the needed padding for the buffer, we calculate here the
           * original buffer_size reversing the surface_size calculation:
           *
           * surface_size = isl_align(buffer_size, 4) +
           *                (isl_align(buffer_size) - buffer_size)
           *
           * buffer_size = surface_size & ~3 - surface_size & 3
           */
          brw_reg size_padding  = ubld.AND(ret_payload, brw_imm_ud(3));
          brw_reg size_aligned4 = ubld.AND(ret_payload, brw_imm_ud(~3));
          brw_reg buffer_size   = ubld.ADD(size_aligned4, negate(size_padding));
    
          bld.MOV(retype(dest, ret_payload.type), component(buffer_size, 0));
          break;
       }
    
       case nir_intrinsic_load_subgroup_size:
          /* This should only happen for fragment shaders because every other case
           * is lowered in NIR so we can optimize on it.
           */
          assert(s.stage == MESA_SHADER_FRAGMENT);
          bld.MOV(retype(dest, BRW_TYPE_D), brw_imm_d(s.dispatch_width));
          break;
    
       case nir_intrinsic_load_subgroup_invocation:
          bld.MOV(retype(dest, BRW_TYPE_UD), bld.LOAD_SUBGROUP_INVOCATION());
          break;
    
       case nir_intrinsic_load_subgroup_eq_mask:
       case nir_intrinsic_load_subgroup_ge_mask:
       case nir_intrinsic_load_subgroup_gt_mask:
       case nir_intrinsic_load_subgroup_le_mask:
       case nir_intrinsic_load_subgroup_lt_mask:
          unreachable("not reached");
    
       case nir_intrinsic_ddx_fine:
          bld.emit(FS_OPCODE_DDX_FINE, retype(dest, BRW_TYPE_F),
                   retype(get_nir_src(ntb, instr->src[0]), BRW_TYPE_F));
          break;
       case nir_intrinsic_ddx:
       case nir_intrinsic_ddx_coarse:
          bld.emit(FS_OPCODE_DDX_COARSE, retype(dest, BRW_TYPE_F),
                   retype(get_nir_src(ntb, instr->src[0]), BRW_TYPE_F));
          break;
       case nir_intrinsic_ddy_fine:
          bld.emit(FS_OPCODE_DDY_FINE, retype(dest, BRW_TYPE_F),
                   retype(get_nir_src(ntb, instr->src[0]), BRW_TYPE_F));
          break;
       case nir_intrinsic_ddy:
       case nir_intrinsic_ddy_coarse:
          bld.emit(FS_OPCODE_DDY_COARSE, retype(dest, BRW_TYPE_F),
                   retype(get_nir_src(ntb, instr->src[0]), BRW_TYPE_F));
          break;
    
       case nir_intrinsic_vote_any:
       case nir_intrinsic_vote_all:
       case nir_intrinsic_quad_vote_any:
       case nir_intrinsic_quad_vote_all: {
          const bool any = instr->intrinsic == nir_intrinsic_vote_any ||
                           instr->intrinsic == nir_intrinsic_quad_vote_any;
          const bool quad = instr->intrinsic == nir_intrinsic_quad_vote_any ||
                            instr->intrinsic == nir_intrinsic_quad_vote_all;
    
          brw_reg cond = get_nir_src(ntb, instr->src[0]);
          const unsigned cluster_size = quad ? 4 : s.dispatch_width;
    
          bld.emit(any ? SHADER_OPCODE_VOTE_ANY : SHADER_OPCODE_VOTE_ALL,
                   retype(dest, BRW_TYPE_UD), cond, brw_imm_ud(cluster_size));
    
          break;
       }
    
       case nir_intrinsic_vote_feq:
       case nir_intrinsic_vote_ieq: {
          brw_reg value = get_nir_src(ntb, instr->src[0]);
          if (instr->intrinsic == nir_intrinsic_vote_feq) {
             const unsigned bit_size = nir_src_bit_size(instr->src[0]);
             value.type = bit_size == 8 ? BRW_TYPE_B :
                brw_type_with_size(BRW_TYPE_F, bit_size);
          }
          bld.emit(SHADER_OPCODE_VOTE_EQUAL, retype(dest, BRW_TYPE_D), value);
          break;
       }
    
       case nir_intrinsic_ballot: {
          if (instr->def.bit_size > 32) {
             dest.type = BRW_TYPE_UQ;
          } else {
             dest.type = BRW_TYPE_UD;
          }
    
          brw_reg value = get_nir_src(ntb, instr->src[0]);
    
          /* A ballot will always be at the full dispatch width even if the
           * use of the ballot result is smaller. If the source is_scalar,
           * it may be allocated at less than the full dispatch width (e.g.,
           * allocated at SIMD8 with SIMD32 dispatch). The input may or may
           * not be stride=0. If it is not, the generated ballot
           *
           *    ballot(32) dst, value<1>
           *
           * is invalid because it will read out of bounds from value.
           *
           * To account for this, modify the stride of an is_scalar input to be
           * zero.
           */
          if (value.is_scalar)
             value = component(value, 0);
    
          /* Note the use of bld here instead of xbld. As mentioned above, the
           * ballot must execute on all SIMD lanes regardless of the amount of
           * data (i.e., scalar or not scalar) generated.
           */
          fs_inst *inst = bld.emit(SHADER_OPCODE_BALLOT, dest, value);
    
          if (dest.is_scalar)
             inst->size_written = dest.component_size(xbld.dispatch_width());
    
          break;
       }
    
       case nir_intrinsic_read_invocation: {
          const brw_reg value = get_nir_src(ntb, instr->src[0]);
          const brw_reg invocation = get_nir_src_imm(ntb, instr->src[1]);
    
          bld.emit(SHADER_OPCODE_READ_FROM_CHANNEL, retype(dest, value.type),
                   value, invocation);
          break;
       }
    
       case nir_intrinsic_read_first_invocation: {
          const brw_reg value = get_nir_src(ntb, instr->src[0]);
    
          bld.emit(SHADER_OPCODE_READ_FROM_LIVE_CHANNEL, retype(dest, value.type), value);
          break;
       }
    
       case nir_intrinsic_shuffle: {
          const brw_reg value = get_nir_src(ntb, instr->src[0]);
          brw_reg index = get_nir_src(ntb, instr->src[1]);
    
          if (devinfo->ver >= 30) {
             /* Mask index to constrain it to be within the valid range in
              * order to avoid potentially reading past the end of the GRF
              * file, which can lead to hangs on Xe3+ with VRT enabled.
              */
             const brw_reg tmp = bld.vgrf(BRW_TYPE_UD);
             bld.AND(tmp, index, brw_imm_ud(s.dispatch_width - 1));
             index = tmp;
          }
    
          bld.emit(SHADER_OPCODE_SHUFFLE, retype(dest, value.type), value, index);
          break;
       }
    
       case nir_intrinsic_first_invocation: {
          brw_reg tmp = bld.vgrf(BRW_TYPE_UD);
          bld.exec_all().emit(SHADER_OPCODE_FIND_LIVE_CHANNEL, tmp);
          bld.MOV(retype(dest, BRW_TYPE_UD),
                  brw_reg(component(tmp, 0)));
          break;
       }
    
       case nir_intrinsic_last_invocation: {
          brw_reg tmp = bld.vgrf(BRW_TYPE_UD);
          bld.exec_all().emit(SHADER_OPCODE_FIND_LAST_LIVE_CHANNEL, tmp);
          bld.MOV(retype(dest, BRW_TYPE_UD),
                  brw_reg(component(tmp, 0)));
          break;
       }
    
       case nir_intrinsic_quad_broadcast: {
          const brw_reg value = get_nir_src(ntb, instr->src[0]);
          const unsigned index = nir_src_as_uint(instr->src[1]);
    
          bld.emit(SHADER_OPCODE_CLUSTER_BROADCAST, retype(dest, value.type),
                   value, brw_imm_ud(index), brw_imm_ud(4));
          break;
       }
    
       case nir_intrinsic_quad_swap_horizontal:
       case nir_intrinsic_quad_swap_vertical:
       case nir_intrinsic_quad_swap_diagonal: {
          const brw_reg value = get_nir_src(ntb, instr->src[0]);
    
          enum brw_swap_direction dir;
          switch (instr->intrinsic) {
          case nir_intrinsic_quad_swap_horizontal: dir = BRW_SWAP_HORIZONTAL; break;
          case nir_intrinsic_quad_swap_vertical:   dir = BRW_SWAP_VERTICAL;   break;
          case nir_intrinsic_quad_swap_diagonal:   dir = BRW_SWAP_DIAGONAL;   break;
          default: unreachable("invalid quad swap");
          }
    
          bld.emit(SHADER_OPCODE_QUAD_SWAP, retype(dest, value.type),
                   value, brw_imm_ud(dir));
          break;
       }
    
       case nir_intrinsic_reduce: {
          brw_reg src = get_nir_src(ntb, instr->src[0]);
          nir_op op = (nir_op)nir_intrinsic_reduction_op(instr);
          enum brw_reduce_op brw_op = brw_reduce_op_for_nir_reduction_op(op);
          unsigned cluster_size = nir_intrinsic_cluster_size(instr);
          if (cluster_size == 0 || cluster_size > s.dispatch_width)
             cluster_size = s.dispatch_width;
    
          /* Figure out the source type */
          src.type = brw_type_for_nir_type(devinfo,
             (nir_alu_type)(nir_op_infos[op].input_types[0] |
                            nir_src_bit_size(instr->src[0])));
    
          bld.emit(SHADER_OPCODE_REDUCE, retype(dest, src.type), src,
                   brw_imm_ud(brw_op), brw_imm_ud(cluster_size));
          break;
       }
    
       case nir_intrinsic_inclusive_scan:
       case nir_intrinsic_exclusive_scan: {
          brw_reg src = get_nir_src(ntb, instr->src[0]);
          nir_op op = (nir_op)nir_intrinsic_reduction_op(instr);
          enum brw_reduce_op brw_op = brw_reduce_op_for_nir_reduction_op(op);
    
          /* Figure out the source type */
          src.type = brw_type_for_nir_type(devinfo,
             (nir_alu_type)(nir_op_infos[op].input_types[0] |
                            nir_src_bit_size(instr->src[0])));
    
          enum opcode opcode = instr->intrinsic == nir_intrinsic_exclusive_scan ?
                SHADER_OPCODE_EXCLUSIVE_SCAN : SHADER_OPCODE_INCLUSIVE_SCAN;
    
          bld.emit(opcode, retype(dest, src.type), src, brw_imm_ud(brw_op));
          break;
       }
    
       case nir_intrinsic_load_topology_id_intel: {
          /* These move around basically every hardware generation, so don't
           * do any unbounded checks and fail if the platform hasn't explicitly
           * been enabled here.
           */
          assert(devinfo->ver >= 12 && devinfo->ver <= 30);
    
          /* Here is what the layout of SR0 looks like on Gfx12
           * https://gfxspecs.intel.com/Predator/Home/Index/47256
           *   [13:11] : Slice ID.
           *   [10:9]  : Dual-SubSlice ID
           *   [8]     : SubSlice ID
           *   [7]     : EUID[2] (aka EU Row ID)
           *   [6]     : Reserved
           *   [5:4]   : EUID[1:0]
           *   [2:0]   : Thread ID
           *
           * Xe2: Engine 3D and GPGPU Programs, EU Overview, Registers and
           * Register Regions, ARF Registers, State Register,
           * https://gfxspecs.intel.com/Predator/Home/Index/56623
           *   [15:11] : Slice ID.
           *   [9:8]   : SubSlice ID
           *   [6:4]   : EUID
           *   [2:0]   : Thread ID
           *
           * Xe3: Engine 3D and GPGPU Programs, EU Overview, Registers and
           * Register Regions, ARF Registers, State Register.
           * Bspec 56623 (r55736)
           *
           *   [17:14] : Slice ID.
           *   [11:8]  : SubSlice ID
           *   [6:4]   : EUID
           *   [3:0]   : Thread ID
           */
          brw_reg raw_id = bld.vgrf(BRW_TYPE_UD);
          bld.UNDEF(raw_id);
          bld.emit(SHADER_OPCODE_READ_ARCH_REG, raw_id, retype(brw_sr0_reg(0),
                                                               BRW_TYPE_UD));
          switch (nir_intrinsic_base(instr)) {
          case BRW_TOPOLOGY_ID_DSS:
             if (devinfo->ver >= 20) {
                /* Xe2+: 3D and GPGPU Programs, Shared Functions, Ray Tracing:
                 * https://gfxspecs.intel.com/Predator/Home/Index/56936
                 *
                 * Note: DSSID in all formulas below is a logical identifier of an
                 * XeCore (a value that goes from 0 to (number_of_slices *
                 * number_of_XeCores_per_slice -1). SW can get this value from
                 * either:
                 *
                 *  - Message Control Register LogicalSSID field (only in shaders
                 *    eligible for Mid-Thread Preemption).
                 *  - Calculated based of State Register with the following formula:
                 *    DSSID = StateRegister.SliceID * GT_ARCH_SS_PER_SLICE +
                 *    StateRRegister.SubSliceID where GT_SS_PER_SLICE is an
                 *    architectural parameter defined per product SKU.
                 *
                 * We are using the state register to calculate the DSSID.
                 */
                const uint32_t slice_id_mask = devinfo->ver >= 30 ?
                                               INTEL_MASK(17, 14) :
                                               INTEL_MASK(15, 11);
                const uint32_t slice_id_shift = devinfo->ver >= 30 ? 14 : 11;
    
                const uint32_t subslice_id_mask = devinfo->ver >= 30 ?
                                                  INTEL_MASK(11, 8) :
                                                  INTEL_MASK(9, 8);
                brw_reg slice_id =
                   bld.SHR(bld.AND(raw_id, brw_imm_ud(slice_id_mask)),
                           brw_imm_ud(slice_id_shift));
    
                /* Assert that max subslices covers at least 2 bits that we use for
                 * subslices.
                 */
                unsigned slice_stride = devinfo->max_subslices_per_slice;
                assert(slice_stride >= (1 << 2));
                brw_reg subslice_id =
                   bld.SHR(bld.AND(raw_id, brw_imm_ud(subslice_id_mask)),
                           brw_imm_ud(8));
                bld.ADD(retype(dest, BRW_TYPE_UD),
                        bld.MUL(slice_id, brw_imm_ud(slice_stride)), subslice_id);
             } else {
                /* Get rid of anything below dualsubslice */
                bld.SHR(retype(dest, BRW_TYPE_UD),
                        bld.AND(raw_id, brw_imm_ud(0x3fff)), brw_imm_ud(9));
             }
             break;
          case BRW_TOPOLOGY_ID_EU_THREAD_SIMD: {
             s.limit_dispatch_width(16, "Topology helper for Ray queries, "
                                  "not supported in SIMD32 mode.");
             brw_reg dst = retype(dest, BRW_TYPE_UD);
             brw_reg eu;
    
             if (devinfo->ver >= 20) {
                /* Xe2+: Graphics Engine, 3D and GPGPU Programs, Shared Functions
                 * Ray Tracing,
                 * https://gfxspecs.intel.com/Predator/Home/Index/56936
                 *
                 * SyncStackID = (EUID[2:0] <<  8) | (ThreadID[2:0] << 4) |
                 *               SIMDLaneID[3:0];
                 *
                 * This section just deals with the EUID part.
                 *
                 * The 3bit EU[2:0] we need to build for ray query memory addresses
                 * computations is a bit odd :
                 *
                 *   EU[2:0] = raw_id[6:4] (identified as EUID[2:0])
                 */
                eu = bld.SHL(bld.AND(raw_id, brw_imm_ud(INTEL_MASK(6, 4))),
                             brw_imm_ud(4));
             } else {
                /* EU[3:0] << 7
                 *
                 * The 4bit EU[3:0] we need to build for ray query memory addresses
                 * computations is a bit odd :
                 *
                 *   EU[1:0] = raw_id[5:4] (identified as EUID[1:0])
                 *   EU[2]   = raw_id[8]   (identified as SubSlice ID)
                 *   EU[3]   = raw_id[7]   (identified as EUID[2] or Row ID)
                 */
                brw_reg raw5_4 = bld.AND(raw_id, brw_imm_ud(INTEL_MASK(5, 4)));
                brw_reg raw7   = bld.AND(raw_id, brw_imm_ud(INTEL_MASK(7, 7)));
                brw_reg raw8   = bld.AND(raw_id, brw_imm_ud(INTEL_MASK(8, 8)));
                eu = bld.OR(bld.SHL(raw5_4, brw_imm_ud(3)),
                            bld.OR(bld.SHL(raw7, brw_imm_ud(3)),
                                   bld.SHL(raw8, brw_imm_ud(1))));
             }
    
             brw_reg tid;
             /* Xe3: Graphics Engine, 3D and GPGPU Programs, Shared Functions
              * Ray Tracing, (Bspec 56936 (r56740))
              *
              * SyncStackID = (EUID[2:0] << 8) | (ThreadID[3:0] << 4) |
              * SIMDLaneID[3:0];
              *
              * ThreadID[3:0] << 4 (ThreadID comes from raw_id[3:0])
              *
              * On older platforms (< Xe3):
              * ThreadID[2:0] << 4 (ThreadID comes from raw_id[2:0])
              */
             const uint32_t raw_id_mask = devinfo->ver >= 30 ?
                                          INTEL_MASK(3, 0) :
                                          INTEL_MASK(2, 0);
             tid = bld.SHL(bld.AND(raw_id, brw_imm_ud(raw_id_mask)),
                           brw_imm_ud(4));
    
             /* LaneID[0:3] << 0 (Use subgroup invocation) */
             assert(bld.dispatch_width() <= 16); /* Limit to 4 bits */
             bld.ADD(dst, bld.OR(eu, tid), bld.LOAD_SUBGROUP_INVOCATION());
             break;
          }
          default:
             unreachable("Invalid topology id type");
          }
          break;
       }
    
       case nir_intrinsic_load_btd_stack_id_intel:
          if (s.stage == MESA_SHADER_COMPUTE) {
             assert(brw_cs_prog_data(s.prog_data)->uses_btd_stack_ids);
          } else {
             assert(brw_shader_stage_is_bindless(s.stage));
          }
          /* Stack IDs are always in R1 regardless of whether we're coming from a
           * bindless shader or a regular compute shader.
           */
          bld.MOV(retype(dest, BRW_TYPE_UD),
                  retype(brw_vec8_grf(1 * reg_unit(devinfo), 0), BRW_TYPE_UW));
          break;
    
       case nir_intrinsic_btd_spawn_intel:
          if (s.stage == MESA_SHADER_COMPUTE) {
             assert(brw_cs_prog_data(s.prog_data)->uses_btd_stack_ids);
          } else {
             assert(brw_shader_stage_is_bindless(s.stage));
          }
          /* Make sure all the pointers to resume shaders have landed where other
           * threads can see them.
           */
          emit_rt_lsc_fence(bld, LSC_FENCE_LOCAL, LSC_FLUSH_TYPE_NONE);
    
          bld.emit(SHADER_OPCODE_BTD_SPAWN_LOGICAL, bld.null_reg_ud(),
                   bld.emit_uniformize(get_nir_src(ntb, instr->src[0], -1)),
                   get_nir_src(ntb, instr->src[1]));
          break;
    
       case nir_intrinsic_btd_retire_intel:
          if (s.stage == MESA_SHADER_COMPUTE) {
             assert(brw_cs_prog_data(s.prog_data)->uses_btd_stack_ids);
          } else {
             assert(brw_shader_stage_is_bindless(s.stage));
          }
          /* Make sure all the pointers to resume shaders have landed where other
           * threads can see them.
           */
          emit_rt_lsc_fence(bld, LSC_FENCE_LOCAL, LSC_FLUSH_TYPE_NONE);
          bld.emit(SHADER_OPCODE_BTD_RETIRE_LOGICAL);
          break;
    
       case nir_intrinsic_trace_ray_intel: {
          const bool synchronous = nir_intrinsic_synchronous(instr);
          assert(brw_shader_stage_is_bindless(s.stage) || synchronous);
    
          /* Make sure all the previous RT structure writes are visible to the RT
           * fixed function within the DSS, as well as stack pointers to resume
           * shaders.
           */
          emit_rt_lsc_fence(bld, LSC_FENCE_LOCAL, LSC_FLUSH_TYPE_NONE);
    
          brw_reg srcs[RT_LOGICAL_NUM_SRCS];
    
          brw_reg globals = get_nir_src(ntb, instr->src[0], -1);
          srcs[RT_LOGICAL_SRC_GLOBALS] = bld.emit_uniformize(globals);
          srcs[RT_LOGICAL_SRC_BVH_LEVEL] = get_nir_src(ntb, instr->src[1]);
          srcs[RT_LOGICAL_SRC_TRACE_RAY_CONTROL] = get_nir_src(ntb, instr->src[2]);
          srcs[RT_LOGICAL_SRC_SYNCHRONOUS] = brw_imm_ud(synchronous);
    
          /* Bspec 57508: Structure_SIMD16TraceRayMessage:: RayQuery Enable
           *
           *    "When this bit is set in the header, Trace Ray Message behaves like
           *    a Ray Query. This message requires a write-back message indicating
           *    RayQuery for all valid Rays (SIMD lanes) have completed."
           */
          brw_reg dst = (devinfo->ver >= 20 && synchronous) ?
                        bld.vgrf(BRW_TYPE_UD) :
                        bld.null_reg_ud();
    
          bld.emit(RT_OPCODE_TRACE_RAY_LOGICAL, dst, srcs, RT_LOGICAL_NUM_SRCS);
    
          /* There is no actual value to use in the destination register of the
           * synchronous trace instruction. All of the communication with the HW
           * unit happens through memory reads/writes. So to ensure that the
           * operation has completed before we go read the results in memory, we
           * need a barrier followed by an invalidate before accessing memory.
           */
          if (synchronous) {
             bld.SYNC(TGL_SYNC_ALLWR);
             emit_rt_lsc_fence(bld, LSC_FENCE_LOCAL, LSC_FLUSH_TYPE_INVALIDATE);
          }
          break;
       }
    
       default:
    #ifndef NDEBUG
          assert(instr->intrinsic < nir_num_intrinsics);
          fprintf(stderr, "intrinsic: %s\n", nir_intrinsic_infos[instr->intrinsic].name);
    #endif
          unreachable("unknown intrinsic");
       }
    }
    
    static enum lsc_data_size
    lsc_bits_to_data_size(unsigned bit_size)
    {
       switch (bit_size / 8) {
       case 1:  return LSC_DATA_SIZE_D8U32;
       case 2:  return LSC_DATA_SIZE_D16U32;
       case 4:  return LSC_DATA_SIZE_D32;
       case 8:  return LSC_DATA_SIZE_D64;
       default:
          unreachable("Unsupported data size.");
       }
    }
    
    /**
     *
     * \param bld  "Normal" builder. This is the full dispatch width of the shader.
     *
     * \param xbld Builder for the intrinsic. If the intrinsic is convergent, this
     *             builder will be scalar_group(). Otherwise it will be the same
     *             as bld.
     *
     * Some places in the function will also use \c ubld. There are two cases of
     * this. Sometimes it is to generate intermediate values as SIMD1. Other
     * places that use \c ubld need a scalar_group() builder to operate on sources
     * to the intrinsic that are is_scalar.
     */
    static void
    fs_nir_emit_memory_access(nir_to_brw_state &ntb,
                              const brw_builder &bld,
                              const brw_builder &xbld,
                              nir_intrinsic_instr *instr)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       fs_visitor &s = ntb.s;
    
       brw_reg srcs[MEMORY_LOGICAL_NUM_SRCS];
    
       /* Start with some default values for most cases */
    
       enum lsc_opcode op = lsc_op_for_nir_intrinsic(instr);
       const bool is_store = !nir_intrinsic_infos[instr->intrinsic].has_dest;
       const bool is_atomic = lsc_opcode_is_atomic(op);
       const bool is_load = !is_store && !is_atomic;
       const bool include_helpers = nir_intrinsic_has_access(instr) &&
          (nir_intrinsic_access(instr) & ACCESS_INCLUDE_HELPERS);
       const unsigned align =
          nir_intrinsic_has_align(instr) ? nir_intrinsic_align(instr) : 0;
       bool no_mask_handle = false;
       int data_src = -1;
    
       srcs[MEMORY_LOGICAL_OPCODE] = brw_imm_ud(op);
       /* BINDING_TYPE, BINDING, and ADDRESS are handled in the switch */
       srcs[MEMORY_LOGICAL_COORD_COMPONENTS] = brw_imm_ud(1);
       srcs[MEMORY_LOGICAL_ALIGNMENT] = brw_imm_ud(align);
       /* DATA_SIZE and CHANNELS are handled below the switch */
       srcs[MEMORY_LOGICAL_FLAGS] =
          brw_imm_ud(include_helpers ? MEMORY_FLAG_INCLUDE_HELPERS : 0);
       /* DATA0 and DATA1 are handled below */
    
       switch (instr->intrinsic) {
       case nir_intrinsic_bindless_image_load:
       case nir_intrinsic_bindless_image_store:
       case nir_intrinsic_bindless_image_atomic:
       case nir_intrinsic_bindless_image_atomic_swap:
          srcs[MEMORY_LOGICAL_BINDING_TYPE] = brw_imm_ud(LSC_ADDR_SURFTYPE_BSS);
          FALLTHROUGH;
       case nir_intrinsic_image_load:
       case nir_intrinsic_image_store:
       case nir_intrinsic_image_atomic:
       case nir_intrinsic_image_atomic_swap:
          srcs[MEMORY_LOGICAL_MODE] = brw_imm_ud(MEMORY_MODE_TYPED);
          srcs[MEMORY_LOGICAL_BINDING] =
             get_nir_image_intrinsic_image(ntb, bld, instr);
    
          if (srcs[MEMORY_LOGICAL_BINDING_TYPE].file == BAD_FILE)
             srcs[MEMORY_LOGICAL_BINDING_TYPE] = brw_imm_ud(LSC_ADDR_SURFTYPE_BTI);
    
          srcs[MEMORY_LOGICAL_ADDRESS] = get_nir_src(ntb, instr->src[1]);
          srcs[MEMORY_LOGICAL_COORD_COMPONENTS] =
             brw_imm_ud(nir_image_intrinsic_coord_components(instr));
    
          data_src = 3;
          break;
    
       case nir_intrinsic_load_ubo_uniform_block_intel:
          srcs[MEMORY_LOGICAL_MODE] = brw_imm_ud(MEMORY_MODE_CONSTANT);
          FALLTHROUGH;
       case nir_intrinsic_load_ssbo:
       case nir_intrinsic_store_ssbo:
       case nir_intrinsic_ssbo_atomic:
       case nir_intrinsic_ssbo_atomic_swap:
       case nir_intrinsic_load_ssbo_block_intel:
       case nir_intrinsic_store_ssbo_block_intel:
       case nir_intrinsic_load_ssbo_uniform_block_intel:
          if (srcs[MEMORY_LOGICAL_MODE].file == BAD_FILE)
             srcs[MEMORY_LOGICAL_MODE] = brw_imm_ud(MEMORY_MODE_UNTYPED);
          srcs[MEMORY_LOGICAL_BINDING_TYPE] =
             brw_imm_ud(get_nir_src_bindless(ntb, instr->src[is_store ? 1 : 0]) ?
                        LSC_ADDR_SURFTYPE_BSS : LSC_ADDR_SURFTYPE_BTI);
          srcs[MEMORY_LOGICAL_BINDING] =
             get_nir_buffer_intrinsic_index(ntb, bld, instr, &no_mask_handle);
          srcs[MEMORY_LOGICAL_ADDRESS] =
             get_nir_src_imm(ntb, instr->src[is_store ? 2 : 1]);
    
          data_src = is_atomic ? 2 : 0;
          break;
       case nir_intrinsic_load_shared:
       case nir_intrinsic_store_shared:
       case nir_intrinsic_shared_atomic:
       case nir_intrinsic_shared_atomic_swap:
       case nir_intrinsic_load_shared_block_intel:
       case nir_intrinsic_store_shared_block_intel:
       case nir_intrinsic_load_shared_uniform_block_intel: {
          srcs[MEMORY_LOGICAL_MODE] = brw_imm_ud(MEMORY_MODE_SHARED_LOCAL);
          srcs[MEMORY_LOGICAL_BINDING_TYPE] = brw_imm_ud(LSC_ADDR_SURFTYPE_FLAT);
    
          const brw_reg nir_src = get_nir_src(ntb, instr->src[is_store ? 1 : 0]);
          const brw_builder ubld = nir_src.is_scalar ? bld.scalar_group() : bld;
    
          /* If the logical address is not uniform, a call to emit_uniformize
           * below will fix it up.
           */
          srcs[MEMORY_LOGICAL_ADDRESS] =
             ubld.ADD(retype(nir_src, BRW_TYPE_UD),
                      brw_imm_ud(nir_intrinsic_base(instr)));
    
          /* If nir_src is_scalar, the MEMORY_LOGICAL_ADDRESS will be allocated at
           * scalar_group() size and will have every component the same
           * value. This is the definition of is_scalar. Much more importantly,
           * setting is_scalar properly also ensures that emit_uniformize (below)
           * will handle the value as scalar_group() size instead of full dispatch
           * width.
           */
          srcs[MEMORY_LOGICAL_ADDRESS].is_scalar = nir_src.is_scalar;
    
          data_src = is_atomic ? 1 : 0;
          no_mask_handle = true;
          break;
       }
       case nir_intrinsic_load_scratch:
       case nir_intrinsic_store_scratch: {
          srcs[MEMORY_LOGICAL_MODE] = brw_imm_ud(MEMORY_MODE_SCRATCH);
    
          const nir_src &addr = instr->src[is_store ? 1 : 0];
    
          if (devinfo->verx10 >= 125) {
             srcs[MEMORY_LOGICAL_BINDING_TYPE] = brw_imm_ud(LSC_ADDR_SURFTYPE_SS);
    
             const brw_builder ubld = bld.exec_all().group(8 * reg_unit(devinfo), 0);
             brw_reg bind = ubld.AND(retype(brw_vec1_grf(0, 5), BRW_TYPE_UD),
                                     brw_imm_ud(INTEL_MASK(31, 10)));
             if (devinfo->ver >= 20)
                bind = ubld.SHR(bind, brw_imm_ud(4));
    
             /* load_scratch / store_scratch cannot be is_scalar yet. */
             assert(xbld.dispatch_width() == bld.dispatch_width());
    
             srcs[MEMORY_LOGICAL_BINDING] = component(bind, 0);
             srcs[MEMORY_LOGICAL_ADDRESS] =
                swizzle_nir_scratch_addr(ntb, bld, addr, false);
          } else {
             unsigned bit_size =
                is_store ? nir_src_bit_size(instr->src[0]) : instr->def.bit_size;
             bool dword_aligned = align >= 4 && bit_size == 32;
    
             /* load_scratch / store_scratch cannot be is_scalar yet. */
             assert(xbld.dispatch_width() == bld.dispatch_width());
    
             srcs[MEMORY_LOGICAL_BINDING_TYPE] =
                brw_imm_ud(LSC_ADDR_SURFTYPE_FLAT);
             srcs[MEMORY_LOGICAL_ADDRESS] =
                swizzle_nir_scratch_addr(ntb, bld, addr, dword_aligned);
          }
    
          if (is_store)
             ++s.shader_stats.spill_count;
          else
             ++s.shader_stats.fill_count;
    
          data_src = 0;
          break;
       }
    
       case nir_intrinsic_load_global_constant_uniform_block_intel:
       case nir_intrinsic_load_global:
       case nir_intrinsic_load_global_constant:
       case nir_intrinsic_store_global:
       case nir_intrinsic_global_atomic:
       case nir_intrinsic_global_atomic_swap:
       case nir_intrinsic_load_global_block_intel:
       case nir_intrinsic_store_global_block_intel:
          srcs[MEMORY_LOGICAL_MODE] = brw_imm_ud(MEMORY_MODE_UNTYPED);
          srcs[MEMORY_LOGICAL_BINDING_TYPE] = brw_imm_ud(LSC_ADDR_SURFTYPE_FLAT);
          srcs[MEMORY_LOGICAL_ADDRESS] = get_nir_src(ntb, instr->src[is_store ? 1 : 0]);
          no_mask_handle = srcs[MEMORY_LOGICAL_ADDRESS].is_scalar;
    
          data_src = is_atomic ? 1 : 0;
          break;
    
       default:
          unreachable("unknown memory intrinsic");
       }
    
       unsigned components = is_store ? instr->src[data_src].ssa->num_components
                                      : instr->def.num_components;
       if (components == 0)
          components = instr->num_components;
    
       srcs[MEMORY_LOGICAL_COMPONENTS] = brw_imm_ud(components);
    
       const unsigned nir_bit_size =
          is_store ? instr->src[data_src].ssa->bit_size : instr->def.bit_size;
       enum lsc_data_size data_size = lsc_bits_to_data_size(nir_bit_size);
       uint32_t data_bit_size = lsc_data_size_bytes(data_size) * 8;
    
       srcs[MEMORY_LOGICAL_DATA_SIZE] = brw_imm_ud(data_size);
    
       const brw_reg_type data_type =
          brw_type_with_size(BRW_TYPE_UD, data_bit_size);
       const brw_reg_type nir_data_type =
          brw_type_with_size(BRW_TYPE_UD, nir_bit_size);
       assert(data_bit_size >= nir_bit_size);
    
       if (!is_load) {
          for (unsigned i = 0; i < lsc_op_num_data_values(op); i++) {
             brw_reg nir_src =
                retype(get_nir_src(ntb, instr->src[data_src + i], -1), nir_data_type);
    
             if (data_bit_size > nir_bit_size) {
                /* Expand e.g. D16 to D16U32 */
                srcs[MEMORY_LOGICAL_DATA0 + i] = xbld.vgrf(data_type, components);
                for (unsigned c = 0; c < components; c++) {
                   xbld.MOV(offset(srcs[MEMORY_LOGICAL_DATA0 + i], xbld, c),
                            offset(nir_src, xbld, c));
                }
             } else {
                srcs[MEMORY_LOGICAL_DATA0 + i] = nir_src;
             }
          }
       }
    
       brw_reg dest, nir_dest;
       if (!is_store) {
          nir_dest = retype(get_nir_def(ntb, instr->def), nir_data_type);
          dest = data_bit_size > nir_bit_size ? xbld.vgrf(data_type, components)
                                              : nir_dest;
       }
    
       enum opcode opcode = is_load ? SHADER_OPCODE_MEMORY_LOAD_LOGICAL :
                            is_store ? SHADER_OPCODE_MEMORY_STORE_LOGICAL :
                            SHADER_OPCODE_MEMORY_ATOMIC_LOGICAL;
    
       const bool convergent_block_load =
          instr->intrinsic == nir_intrinsic_load_ubo_uniform_block_intel ||
          instr->intrinsic == nir_intrinsic_load_ssbo_uniform_block_intel ||
          instr->intrinsic == nir_intrinsic_load_shared_uniform_block_intel ||
          instr->intrinsic == nir_intrinsic_load_global_constant_uniform_block_intel;
       const bool block = convergent_block_load ||
          instr->intrinsic == nir_intrinsic_load_global_block_intel ||
          instr->intrinsic == nir_intrinsic_load_shared_block_intel ||
          instr->intrinsic == nir_intrinsic_load_ssbo_block_intel ||
          instr->intrinsic == nir_intrinsic_store_global_block_intel ||
          instr->intrinsic == nir_intrinsic_store_shared_block_intel ||
          instr->intrinsic == nir_intrinsic_store_ssbo_block_intel;
    
       fs_inst *inst;
    
       if (!block) {
          inst = xbld.emit(opcode, dest, srcs, MEMORY_LOGICAL_NUM_SRCS);
          inst->size_written *= components;
    
          if (dest.file != BAD_FILE && data_bit_size > nir_bit_size) {
             /* Shrink e.g. D16U32 result back to D16 */
             for (unsigned i = 0; i < components; i++) {
                xbld.MOV(offset(nir_dest, xbld, i),
                         subscript(offset(dest, xbld, i), nir_dest.type, 0));
             }
          }
       } else {
          assert(nir_bit_size == 32);
    
          srcs[MEMORY_LOGICAL_FLAGS] =
             brw_imm_ud(MEMORY_FLAG_TRANSPOSE | srcs[MEMORY_LOGICAL_FLAGS].ud);
          srcs[MEMORY_LOGICAL_ADDRESS] =
             bld.emit_uniformize(srcs[MEMORY_LOGICAL_ADDRESS]);
    
          const brw_builder ubld = bld.exec_all().group(1, 0);
          unsigned total, done;
          unsigned first_read_component = 0;
    
          if (convergent_block_load) {
             /* If the address is a constant and alignment permits, skip unread
              * leading and trailing components.  (It's probably not worth the
              * extra address math for non-constant addresses.)
              *
              * Note that SLM block loads on HDC platforms need to be 16B aligned.
              */
             if (srcs[MEMORY_LOGICAL_ADDRESS].file == IMM &&
                 align >= data_bit_size / 8 &&
                 (devinfo->has_lsc ||
                  srcs[MEMORY_LOGICAL_MODE].ud != MEMORY_MODE_SHARED_LOCAL)) {
                first_read_component = nir_def_first_component_read(&instr->def);
                unsigned last_component = nir_def_last_component_read(&instr->def);
                srcs[MEMORY_LOGICAL_ADDRESS].u64 +=
                   first_read_component * (data_bit_size / 8);
                components = last_component - first_read_component + 1;
             }
    
             total = ALIGN(components, REG_SIZE * reg_unit(devinfo) / 4);
             dest = ubld.vgrf(BRW_TYPE_UD, total);
          } else {
             total = components * bld.dispatch_width();
             dest = nir_dest;
          }
    
          brw_reg src = srcs[MEMORY_LOGICAL_DATA0];
    
          unsigned block_comps = components;
    
          for (done = 0; done < total; done += block_comps) {
             block_comps = choose_block_size_dwords(devinfo, total - done);
             const unsigned block_bytes = block_comps * (nir_bit_size / 8);
    
             srcs[MEMORY_LOGICAL_COMPONENTS] = brw_imm_ud(block_comps);
    
             brw_reg dst_offset = is_store ? brw_reg() :
                retype(byte_offset(dest, done * 4), BRW_TYPE_UD);
             if (is_store) {
                srcs[MEMORY_LOGICAL_DATA0] =
                   retype(byte_offset(src, done * 4), BRW_TYPE_UD);
             }
    
             inst = ubld.emit(opcode, dst_offset, srcs, MEMORY_LOGICAL_NUM_SRCS);
             inst->has_no_mask_send_params = no_mask_handle;
             if (is_load)
                inst->size_written = block_bytes;
    
             if (brw_type_size_bits(srcs[MEMORY_LOGICAL_ADDRESS].type) == 64) {
                increment_a64_address(ubld, srcs[MEMORY_LOGICAL_ADDRESS],
                                      block_bytes, no_mask_handle);
             } else {
                srcs[MEMORY_LOGICAL_ADDRESS] =
                   ubld.ADD(retype(srcs[MEMORY_LOGICAL_ADDRESS], BRW_TYPE_UD),
                            brw_imm_ud(block_bytes));
             }
          }
          assert(done == total);
    
          if (convergent_block_load) {
             for (unsigned c = 0; c < components; c++) {
                xbld.MOV(retype(offset(nir_dest, xbld, first_read_component + c),
                                BRW_TYPE_UD),
                         component(dest, c));
             }
          }
       }
    }
    
    static void
    fs_nir_emit_texture(nir_to_brw_state &ntb,
                        nir_tex_instr *instr)
    {
       const intel_device_info *devinfo = ntb.devinfo;
       const brw_builder &bld = ntb.bld;
    
       brw_reg srcs[TEX_LOGICAL_NUM_SRCS];
    
       /* SKL PRMs: Volume 7: 3D-Media-GPGPU:
        *
        *    "The Pixel Null Mask field, when enabled via the Pixel Null Mask
        *     Enable will be incorect for sample_c when applied to a surface with
        *     64-bit per texel format such as R16G16BA16_UNORM. Pixel Null mask
        *     Enable may incorrectly report pixels as referencing a Null surface."
        *
        * We'll take care of this in NIR.
        */
       assert(!instr->is_sparse || srcs[TEX_LOGICAL_SRC_SHADOW_C].file == BAD_FILE);
    
       srcs[TEX_LOGICAL_SRC_RESIDENCY] = brw_imm_ud(instr->is_sparse);
    
       int lod_components = 0;
    
       /* The hardware requires a LOD for buffer textures */
       if (instr->sampler_dim == GLSL_SAMPLER_DIM_BUF)
          srcs[TEX_LOGICAL_SRC_LOD] = brw_imm_d(0);
    
       ASSERTED bool got_lod = false;
       ASSERTED bool got_bias = false;
       bool pack_lod_bias_and_offset = false;
       uint32_t header_bits = 0;
       for (unsigned i = 0; i < instr->num_srcs; i++) {
          nir_src nir_src = instr->src[i].src;
          brw_reg src = get_nir_src(ntb, nir_src, -1);
    
          /* If the source is not a vector (e.g., a 1D texture coordinate), then
           * the eventual LOAD_PAYLOAD lowering will not properly adjust the
           * stride, etc., so do it now.
           */
          if (nir_tex_instr_src_size(instr, i) == 1)
             src = offset(src, bld, 0);
    
          switch (instr->src[i].src_type) {
          case nir_tex_src_bias:
             assert(!got_lod);
             got_bias = true;
    
             srcs[TEX_LOGICAL_SRC_LOD] =
                retype(get_nir_src_imm(ntb, instr->src[i].src), BRW_TYPE_F);
             break;
          case nir_tex_src_comparator:
             srcs[TEX_LOGICAL_SRC_SHADOW_C] = retype(src, BRW_TYPE_F);
             break;
          case nir_tex_src_coord:
             switch (instr->op) {
             case nir_texop_txf:
             case nir_texop_txf_ms:
             case nir_texop_txf_ms_mcs_intel:
             case nir_texop_samples_identical:
                srcs[TEX_LOGICAL_SRC_COORDINATE] = retype(src, BRW_TYPE_D);
                break;
             default:
                srcs[TEX_LOGICAL_SRC_COORDINATE] = retype(src, BRW_TYPE_F);
                break;
             }
             break;
          case nir_tex_src_ddx:
             srcs[TEX_LOGICAL_SRC_LOD] = retype(src, BRW_TYPE_F);
             lod_components = nir_tex_instr_src_size(instr, i);
             break;
          case nir_tex_src_ddy:
             srcs[TEX_LOGICAL_SRC_LOD2] = retype(src, BRW_TYPE_F);
             break;
          case nir_tex_src_lod:
             assert(!got_bias);
             got_lod = true;
    
             switch (instr->op) {
             case nir_texop_txs:
                srcs[TEX_LOGICAL_SRC_LOD] =
                   retype(get_nir_src_imm(ntb, instr->src[i].src), BRW_TYPE_UD);
                break;
             case nir_texop_txf:
                srcs[TEX_LOGICAL_SRC_LOD] =
                   retype(get_nir_src_imm(ntb, instr->src[i].src), BRW_TYPE_D);
                break;
             default:
                srcs[TEX_LOGICAL_SRC_LOD] =
                   retype(get_nir_src_imm(ntb, instr->src[i].src), BRW_TYPE_F);
                break;
             }
             break;
          case nir_tex_src_min_lod:
             srcs[TEX_LOGICAL_SRC_MIN_LOD] =
                retype(get_nir_src_imm(ntb, instr->src[i].src), BRW_TYPE_F);
             break;
          case nir_tex_src_ms_index:
             srcs[TEX_LOGICAL_SRC_SAMPLE_INDEX] = retype(src, BRW_TYPE_UD);
             break;
    
          case nir_tex_src_offset: {
             uint32_t offset_bits = 0;
             if (brw_texture_offset(instr, i, &offset_bits)) {
                header_bits |= offset_bits;
             } else {
                /* On gfx12.5+, if the offsets are not both constant and in the
                 * {-8,7} range, nir_lower_tex() will have already lowered the
                 * source offset. So we should never reach this point.
                 */
                assert(devinfo->verx10 < 125);
                srcs[TEX_LOGICAL_SRC_TG4_OFFSET] =
                   retype(src, BRW_TYPE_D);
             }
             break;
          }
    
          case nir_tex_src_projector:
             unreachable("should be lowered");
    
          case nir_tex_src_texture_offset: {
             assert(srcs[TEX_LOGICAL_SRC_SURFACE].file == BAD_FILE);
             /* Emit code to evaluate the actual indexing expression */
             srcs[TEX_LOGICAL_SRC_SURFACE] =
                bld.emit_uniformize(bld.ADD(retype(src, BRW_TYPE_UD),
                                            brw_imm_ud(instr->texture_index)));
             assert(srcs[TEX_LOGICAL_SRC_SURFACE].file != BAD_FILE);
             break;
          }
    
          case nir_tex_src_sampler_offset: {
             /* Emit code to evaluate the actual indexing expression */
             srcs[TEX_LOGICAL_SRC_SAMPLER] =
                bld.emit_uniformize(bld.ADD(retype(src, BRW_TYPE_UD),
                                            brw_imm_ud(instr->sampler_index)));
             break;
          }
    
          case nir_tex_src_texture_handle:
             assert(nir_tex_instr_src_index(instr, nir_tex_src_texture_offset) == -1);
             srcs[TEX_LOGICAL_SRC_SURFACE] = brw_reg();
             srcs[TEX_LOGICAL_SRC_SURFACE_HANDLE] = bld.emit_uniformize(src);
             break;
    
          case nir_tex_src_sampler_handle:
             assert(nir_tex_instr_src_index(instr, nir_tex_src_sampler_offset) == -1);
             srcs[TEX_LOGICAL_SRC_SAMPLER] = brw_reg();
             srcs[TEX_LOGICAL_SRC_SAMPLER_HANDLE] = bld.emit_uniformize(src);
             break;
    
          case nir_tex_src_ms_mcs_intel:
             assert(instr->op == nir_texop_txf_ms);
             srcs[TEX_LOGICAL_SRC_MCS] = retype(src, BRW_TYPE_D);
             break;
    
          /* If this parameter is present, we are packing offset U, V and LOD/Bias
           * into a single (32-bit) value.
           */
          case nir_tex_src_backend2:
             assert(instr->op == nir_texop_tg4);
             pack_lod_bias_and_offset = true;
             srcs[TEX_LOGICAL_SRC_LOD] =
                retype(get_nir_src_imm(ntb, instr->src[i].src), BRW_TYPE_F);
             break;
    
          /* If this parameter is present, we are packing either the explicit LOD
           * or LOD bias and the array index into a single (32-bit) value when
           * 32-bit texture coordinates are used.
           */
          case nir_tex_src_backend1:
             assert(!got_lod && !got_bias);
             got_lod = true;
             assert(instr->op == nir_texop_txl || instr->op == nir_texop_txb);
             srcs[TEX_LOGICAL_SRC_LOD] =
                retype(get_nir_src_imm(ntb, instr->src[i].src), BRW_TYPE_F);
             break;
    
          default:
             unreachable("unknown texture source");
          }
       }
    
       /* If the surface or sampler were not specified through sources, use the
        * instruction index.
        */
       if (srcs[TEX_LOGICAL_SRC_SURFACE].file == BAD_FILE &&
           srcs[TEX_LOGICAL_SRC_SURFACE_HANDLE].file == BAD_FILE)
          srcs[TEX_LOGICAL_SRC_SURFACE] = brw_imm_ud(instr->texture_index);
       if (srcs[TEX_LOGICAL_SRC_SAMPLER].file == BAD_FILE &&
           srcs[TEX_LOGICAL_SRC_SAMPLER_HANDLE].file == BAD_FILE)
          srcs[TEX_LOGICAL_SRC_SAMPLER] = brw_imm_ud(instr->sampler_index);
    
       if (srcs[TEX_LOGICAL_SRC_MCS].file == BAD_FILE &&
           (instr->op == nir_texop_txf_ms ||
            instr->op == nir_texop_samples_identical)) {
          srcs[TEX_LOGICAL_SRC_MCS] =
             emit_mcs_fetch(ntb, srcs[TEX_LOGICAL_SRC_COORDINATE],
                            instr->coord_components,
                            srcs[TEX_LOGICAL_SRC_SURFACE],
                            srcs[TEX_LOGICAL_SRC_SURFACE_HANDLE]);
       }
    
       srcs[TEX_LOGICAL_SRC_COORD_COMPONENTS] = brw_imm_d(instr->coord_components);
       srcs[TEX_LOGICAL_SRC_GRAD_COMPONENTS] = brw_imm_d(lod_components);
    
       enum opcode opcode;
       switch (instr->op) {
       case nir_texop_tex:
          opcode = SHADER_OPCODE_TEX_LOGICAL;
          break;
       case nir_texop_txb:
          opcode = FS_OPCODE_TXB_LOGICAL;
          break;
       case nir_texop_txl:
          opcode = SHADER_OPCODE_TXL_LOGICAL;
          break;
       case nir_texop_txd:
          opcode = SHADER_OPCODE_TXD_LOGICAL;
          break;
       case nir_texop_txf:
          opcode = SHADER_OPCODE_TXF_LOGICAL;
          break;
       case nir_texop_txf_ms:
          /* On Gfx12HP there is only CMS_W available. From the Bspec: Shared
           * Functions - 3D Sampler - Messages - Message Format:
           *
           *   ld2dms REMOVEDBY(GEN:HAS:1406788836)
           */
          if (devinfo->verx10 >= 125)
             opcode = SHADER_OPCODE_TXF_CMS_W_GFX12_LOGICAL;
          else
             opcode = SHADER_OPCODE_TXF_CMS_W_LOGICAL;
          break;
       case nir_texop_txf_ms_mcs_intel:
          opcode = SHADER_OPCODE_TXF_MCS_LOGICAL;
          break;
       case nir_texop_query_levels:
       case nir_texop_txs:
          opcode = SHADER_OPCODE_TXS_LOGICAL;
          break;
       case nir_texop_lod:
          opcode = SHADER_OPCODE_LOD_LOGICAL;
          break;
       case nir_texop_tg4: {
          if (srcs[TEX_LOGICAL_SRC_TG4_OFFSET].file != BAD_FILE) {
             opcode = SHADER_OPCODE_TG4_OFFSET_LOGICAL;
          } else {
             opcode = SHADER_OPCODE_TG4_LOGICAL;
             if (devinfo->ver >= 20) {
                /* If SPV_AMD_texture_gather_bias_lod extension is enabled, all
                 * texture gather functions (ie. the ones which do not take the
                 * extra bias argument and the ones that do) fetch texels from
                 * implicit LOD in fragment shader stage. In all other shader
                 * stages, base level is used instead.
                 */
                if (instr->is_gather_implicit_lod)
                   opcode = SHADER_OPCODE_TG4_IMPLICIT_LOD_LOGICAL;
    
                if (got_bias)
                   opcode = SHADER_OPCODE_TG4_BIAS_LOGICAL;
    
                if (got_lod)
                   opcode = SHADER_OPCODE_TG4_EXPLICIT_LOD_LOGICAL;
    
                if (pack_lod_bias_and_offset) {
                   if (got_lod)
                      opcode = SHADER_OPCODE_TG4_OFFSET_LOD_LOGICAL;
                   if (got_bias)
                      opcode = SHADER_OPCODE_TG4_OFFSET_BIAS_LOGICAL;
                }
             }
          }
          break;
       }
       case nir_texop_texture_samples:
          opcode = SHADER_OPCODE_SAMPLEINFO_LOGICAL;
          break;
       case nir_texop_samples_identical: {
          brw_reg dst = retype(get_nir_def(ntb, instr->def), BRW_TYPE_D);
    
          /* If mcs is an immediate value, it means there is no MCS.  In that case
           * just return false.
           */
          if (srcs[TEX_LOGICAL_SRC_MCS].file == IMM) {
             bld.MOV(dst, brw_imm_ud(0u));
          } else {
             brw_reg tmp =
                bld.OR(srcs[TEX_LOGICAL_SRC_MCS],
                       offset(srcs[TEX_LOGICAL_SRC_MCS], bld, 1));
             bld.CMP(dst, tmp, brw_imm_ud(0u), BRW_CONDITIONAL_EQ);
          }
          return;
       }
       default:
          unreachable("unknown texture opcode");
       }
    
       if (instr->op == nir_texop_tg4) {
          header_bits |= instr->component << 16;
       }
    
       brw_reg nir_def_reg = get_nir_def(ntb, instr->def);
    
       const unsigned dest_size = nir_tex_instr_dest_size(instr);
       unsigned dest_comp;
       if (instr->op != nir_texop_tg4 && instr->op != nir_texop_query_levels) {
          unsigned write_mask = nir_def_components_read(&instr->def);
          assert(write_mask != 0); /* dead code should have been eliminated */
    
          dest_comp = util_last_bit(write_mask) - instr->is_sparse;
       } else {
          dest_comp = 4;
       }
    
       /* Compute the number of physical registers needed to hold a single
        * component and round it up to a physical register count.
        */
       brw_reg_type dst_type = brw_type_for_nir_type(devinfo, instr->dest_type);
       const unsigned grf_size = reg_unit(devinfo) * REG_SIZE;
       const unsigned per_component_regs =
          DIV_ROUND_UP(brw_type_size_bytes(dst_type) * bld.dispatch_width(),
                       grf_size);
       const unsigned total_regs =
          dest_comp * per_component_regs + instr->is_sparse;
       /* Allocate enough space for the components + one physical register for the
        * residency data.
        */
       brw_reg dst = brw_vgrf(
          bld.shader->alloc.allocate(total_regs * reg_unit(devinfo)),
          dst_type);
    
       fs_inst *inst = bld.emit(opcode, dst, srcs, ARRAY_SIZE(srcs));
       inst->offset = header_bits;
       inst->size_written = total_regs * grf_size;
    
       if (srcs[TEX_LOGICAL_SRC_SHADOW_C].file != BAD_FILE)
          inst->shadow_compare = true;
    
       /* Wa_14012688258:
        *
        * Don't trim zeros at the end of payload for sample operations
        * in cube and cube arrays.
        */
       if (instr->sampler_dim == GLSL_SAMPLER_DIM_CUBE &&
           intel_needs_workaround(devinfo, 14012688258)) {
    
          /* Compiler should send U,V,R parameters even if V,R are 0. */
          if (srcs[TEX_LOGICAL_SRC_COORDINATE].file != BAD_FILE)
             assert(instr->coord_components >= 3u);
    
          /* See opt_zero_samples(). */
          inst->keep_payload_trailing_zeros = true;
       }
    
       /* With half-floats returns, the stride into a GRF allocation for each
        * component might be different than where the sampler is storing each
        * component. For example in SIMD8 on DG2 the layout of the data returned
        * by the sampler is as follow for 2 components load:
        *
        *           _______________________________________________________________
        *   g0 : |           unused              |hf7|hf6|hf5|hf4|hf3|hf2|hf1|hf0|
        *   g1 : |           unused              |hf7|hf6|hf5|hf4|hf3|hf2|hf1|hf0|
        *
        * The same issue also happens in SIMD16 on Xe2 because the physical
        * register size has doubled but we're still loading data only on half the
        * register.
        *
        * In those cases we need the special remapping case below.
        */
       const bool non_aligned_component_stride =
          (brw_type_size_bytes(dst_type) * bld.dispatch_width()) % grf_size != 0;
       if (instr->op != nir_texop_query_levels && !instr->is_sparse &&
           !non_aligned_component_stride) {
          /* In most cases we can write directly to the result. */
          inst->dst = nir_def_reg;
       } else {
          /* In other cases, we have to reorganize the sampler message's results
           * a bit to match the NIR intrinsic's expectations.
           */
          brw_reg nir_dest[5];
          for (unsigned i = 0; i < dest_comp; i++)
             nir_dest[i] = byte_offset(dst, i * per_component_regs * grf_size);
    
          for (unsigned i = dest_comp; i < dest_size; i++)
             nir_dest[i].type = dst.type;
    
          if (instr->op == nir_texop_query_levels) {
             /* # levels is in .w */
             if (devinfo->ver == 9) {
                /**
                 * Wa_1940217:
                 *
                 * When a surface of type SURFTYPE_NULL is accessed by resinfo, the
                 * MIPCount returned is undefined instead of 0.
                 */
                fs_inst *mov = bld.MOV(bld.null_reg_d(), dst);
                mov->conditional_mod = BRW_CONDITIONAL_NZ;
                nir_dest[0] = bld.vgrf(BRW_TYPE_D);
                fs_inst *sel =
                   bld.SEL(nir_dest[0], offset(dst, bld, 3), brw_imm_d(0));
                sel->predicate = BRW_PREDICATE_NORMAL;
             } else {
                nir_dest[0] = offset(dst, bld, 3);
             }
          }
    
          /* The residency bits are only in the first component. */
          if (instr->is_sparse) {
             nir_dest[dest_size - 1] =
                component(offset(dst, bld, dest_size - 1), 0);
          }
    
          bld.LOAD_PAYLOAD(nir_def_reg, nir_dest, dest_size, 0);
       }
    }
    
    static void
    fs_nir_emit_jump(nir_to_brw_state &ntb, nir_jump_instr *instr)
    {
       switch (instr->type) {
       case nir_jump_break:
          ntb.bld.emit(BRW_OPCODE_BREAK);
          break;
       case nir_jump_continue:
          ntb.bld.emit(BRW_OPCODE_CONTINUE);
          break;
       case nir_jump_halt:
          ntb.bld.emit(BRW_OPCODE_HALT);
          break;
       case nir_jump_return:
       default:
          unreachable("unknown jump");
       }
    }
    
    static void
    fs_nir_emit_instr(nir_to_brw_state &ntb, nir_instr *instr)
    {
    #ifndef NDEBUG
       if (unlikely(ntb.annotate)) {
          /* Use shader mem_ctx since annotations outlive the NIR conversion. */
          ntb.bld = ntb.bld.annotate(nir_instr_as_str(instr, ntb.s.mem_ctx));
       }
    #endif
    
       switch (instr->type) {
       case nir_instr_type_alu:
          fs_nir_emit_alu(ntb, nir_instr_as_alu(instr), true);
          break;
    
       case nir_instr_type_deref:
          unreachable("All derefs should've been lowered");
          break;
    
       case nir_instr_type_intrinsic:
          switch (ntb.s.stage) {
          case MESA_SHADER_VERTEX:
             fs_nir_emit_vs_intrinsic(ntb, nir_instr_as_intrinsic(instr));
             break;
          case MESA_SHADER_TESS_CTRL:
             fs_nir_emit_tcs_intrinsic(ntb, nir_instr_as_intrinsic(instr));
             break;
          case MESA_SHADER_TESS_EVAL:
             fs_nir_emit_tes_intrinsic(ntb, nir_instr_as_intrinsic(instr));
             break;
          case MESA_SHADER_GEOMETRY:
             fs_nir_emit_gs_intrinsic(ntb, nir_instr_as_intrinsic(instr));
             break;
          case MESA_SHADER_FRAGMENT:
             fs_nir_emit_fs_intrinsic(ntb, nir_instr_as_intrinsic(instr));
             break;
          case MESA_SHADER_COMPUTE:
          case MESA_SHADER_KERNEL:
             fs_nir_emit_cs_intrinsic(ntb, nir_instr_as_intrinsic(instr));
             break;
          case MESA_SHADER_RAYGEN:
          case MESA_SHADER_ANY_HIT:
          case MESA_SHADER_CLOSEST_HIT:
          case MESA_SHADER_MISS:
          case MESA_SHADER_INTERSECTION:
          case MESA_SHADER_CALLABLE:
             fs_nir_emit_bs_intrinsic(ntb, nir_instr_as_intrinsic(instr));
             break;
          case MESA_SHADER_TASK:
             fs_nir_emit_task_intrinsic(ntb, nir_instr_as_intrinsic(instr));
             break;
          case MESA_SHADER_MESH:
             fs_nir_emit_mesh_intrinsic(ntb, nir_instr_as_intrinsic(instr));
             break;
          default:
             unreachable("unsupported shader stage");
          }
          break;
    
       case nir_instr_type_tex:
          fs_nir_emit_texture(ntb, nir_instr_as_tex(instr));
          break;
    
       case nir_instr_type_load_const:
          fs_nir_emit_load_const(ntb, nir_instr_as_load_const(instr));
          break;
    
       case nir_instr_type_undef:
          /* We create a new VGRF for undefs on every use (by handling
           * them in get_nir_src()), rather than for each definition.
           * This helps register coalescing eliminate MOVs from undef.
           */
          break;
    
       case nir_instr_type_jump:
          fs_nir_emit_jump(ntb, nir_instr_as_jump(instr));
          break;
    
       default:
          unreachable("unknown instruction type");
       }
    }
    
    static unsigned
    brw_rnd_mode_from_nir(unsigned mode, unsigned *mask)
    {
       unsigned brw_mode = 0;
       *mask = 0;
    
       if ((FLOAT_CONTROLS_ROUNDING_MODE_RTZ_FP16 |
            FLOAT_CONTROLS_ROUNDING_MODE_RTZ_FP32 |
            FLOAT_CONTROLS_ROUNDING_MODE_RTZ_FP64) &
           mode) {
          brw_mode |= BRW_RND_MODE_RTZ << BRW_CR0_RND_MODE_SHIFT;
          *mask |= BRW_CR0_RND_MODE_MASK;
       }
       if ((FLOAT_CONTROLS_ROUNDING_MODE_RTE_FP16 |
            FLOAT_CONTROLS_ROUNDING_MODE_RTE_FP32 |
            FLOAT_CONTROLS_ROUNDING_MODE_RTE_FP64) &
           mode) {
          brw_mode |= BRW_RND_MODE_RTNE << BRW_CR0_RND_MODE_SHIFT;
          *mask |= BRW_CR0_RND_MODE_MASK;
       }
       if (mode & FLOAT_CONTROLS_DENORM_PRESERVE_FP16) {
          brw_mode |= BRW_CR0_FP16_DENORM_PRESERVE;
          *mask |= BRW_CR0_FP16_DENORM_PRESERVE;
       }
       if (mode & FLOAT_CONTROLS_DENORM_PRESERVE_FP32) {
          brw_mode |= BRW_CR0_FP32_DENORM_PRESERVE;
          *mask |= BRW_CR0_FP32_DENORM_PRESERVE;
       }
       if (mode & FLOAT_CONTROLS_DENORM_PRESERVE_FP64) {
          brw_mode |= BRW_CR0_FP64_DENORM_PRESERVE;
          *mask |= BRW_CR0_FP64_DENORM_PRESERVE;
       }
       if (mode & FLOAT_CONTROLS_DENORM_FLUSH_TO_ZERO_FP16)
          *mask |= BRW_CR0_FP16_DENORM_PRESERVE;
       if (mode & FLOAT_CONTROLS_DENORM_FLUSH_TO_ZERO_FP32)
          *mask |= BRW_CR0_FP32_DENORM_PRESERVE;
       if (mode & FLOAT_CONTROLS_DENORM_FLUSH_TO_ZERO_FP64)
          *mask |= BRW_CR0_FP64_DENORM_PRESERVE;
       if (mode == FLOAT_CONTROLS_DEFAULT_FLOAT_CONTROL_MODE)
          *mask |= BRW_CR0_FP_MODE_MASK;
    
       if (*mask != 0)
          assert((*mask & brw_mode) == brw_mode);
    
       return brw_mode;
    }
    
    static void
    emit_shader_float_controls_execution_mode(nir_to_brw_state &ntb)
    {
       const brw_builder &bld = ntb.bld;
       fs_visitor &s = ntb.s;
    
       unsigned execution_mode = s.nir->info.float_controls_execution_mode;
       if (execution_mode == FLOAT_CONTROLS_DEFAULT_FLOAT_CONTROL_MODE)
          return;
    
       brw_builder ubld = bld.exec_all().group(1, 0);
       brw_builder abld = ubld.annotate("shader floats control execution mode");
       unsigned mask, mode = brw_rnd_mode_from_nir(execution_mode, &mask);
    
       if (mask == 0)
          return;
    
       abld.emit(SHADER_OPCODE_FLOAT_CONTROL_MODE, bld.null_reg_ud(),
                 brw_imm_d(mode), brw_imm_d(mask));
    }
    
    /**
     * Test the dispatch mask packing assumptions of
     * brw_stage_has_packed_dispatch().  Call this from e.g. the top of
     * nir_to_brw() to cause a GPU hang if any shader invocation is
     * executed with an unexpected dispatch mask.
     */
    static UNUSED void
    brw_fs_test_dispatch_packing(const brw_builder &bld)
    {
       const fs_visitor *shader = bld.shader;
       const gl_shader_stage stage = shader->stage;
       const bool uses_vmask =
          stage == MESA_SHADER_FRAGMENT &&
          brw_wm_prog_data(shader->prog_data)->uses_vmask;
    
       if (brw_stage_has_packed_dispatch(shader->devinfo, stage,
                                         shader->max_polygons,
                                         shader->prog_data)) {
          const brw_builder ubld = bld.exec_all().group(1, 0);
          const brw_reg tmp = component(bld.vgrf(BRW_TYPE_UD), 0);
          const brw_reg mask = uses_vmask ? brw_vmask_reg() : brw_dmask_reg();
    
          ubld.ADD(tmp, mask, brw_imm_ud(1));
          ubld.AND(tmp, mask, tmp);
    
          /* This will loop forever if the dispatch mask doesn't have the expected
           * form '2^n-1', in which case tmp will be non-zero.
           */
          bld.emit(BRW_OPCODE_DO);
          bld.CMP(bld.null_reg_ud(), tmp, brw_imm_ud(0), BRW_CONDITIONAL_NZ);
          set_predicate(BRW_PREDICATE_NORMAL, bld.emit(BRW_OPCODE_WHILE));
       }
    }
    
    void
    nir_to_brw(fs_visitor *s)
    {
       nir_to_brw_state ntb = {
          .s       = *s,
          .nir     = s->nir,
          .devinfo = s->devinfo,
          .mem_ctx = ralloc_context(NULL),
          .bld     = brw_builder(s).at_end(),
       };
    
       if (INTEL_DEBUG(DEBUG_ANNOTATION))
          ntb.annotate = true;
    
       if (ENABLE_FS_TEST_DISPATCH_PACKING)
          brw_fs_test_dispatch_packing(ntb.bld);
    
       for (unsigned i = 0; i < s->nir->printf_info_count; i++) {
          brw_stage_prog_data_add_printf(s->prog_data,
                                         s->mem_ctx,
                                         &s->nir->printf_info[i]);
       }
    
       emit_shader_float_controls_execution_mode(ntb);
    
       /* emit the arrays used for inputs and outputs - load/store intrinsics will
        * be converted to reads/writes of these arrays
        */
       fs_nir_setup_outputs(ntb);
       fs_nir_setup_uniforms(ntb.s);
       fs_nir_emit_system_values(ntb);
       ntb.s.last_scratch = ALIGN(ntb.nir->scratch_size, 4) * ntb.s.dispatch_width;
    
       fs_nir_emit_impl(ntb, nir_shader_get_entrypoint((nir_shader *)ntb.nir));
    
       ntb.bld.emit(SHADER_OPCODE_HALT_TARGET);
    
       ralloc_free(ntb.mem_ctx);
    
       brw_shader_phase_update(*s, BRW_SHADER_PHASE_AFTER_NIR);
    }