Edit

IABSD.fr/xenocara/lib/mesa/src/amd/compiler/aco_instruction_selection_setup.cpp

Branch :

  • Show log

    Commit

  • Author : jsg
    Date : 2025-06-05 11:23:11
    Hash : 67d6f117
    Message : Import Mesa 25.0.7

  • lib/mesa/src/amd/compiler/aco_instruction_selection_setup.cpp
  • /*
     * Copyright © 2018 Valve Corporation
     *
     * SPDX-License-Identifier: MIT
     */
    
    #include "aco_instruction_selection.h"
    
    #include "common/nir/ac_nir.h"
    #include "common/sid.h"
    
    #include "nir_control_flow.h"
    #include "nir_builder.h"
    
    #include <vector>
    
    namespace aco {
    
    namespace {
    
    /* Check whether the given SSA def is only used by cross-lane instructions. */
    bool
    only_used_by_cross_lane_instrs(nir_def* ssa, bool follow_phis = true)
    {
       nir_foreach_use (src, ssa) {
          switch (nir_src_parent_instr(src)->type) {
          case nir_instr_type_alu: {
             nir_alu_instr* alu = nir_instr_as_alu(nir_src_parent_instr(src));
             if (alu->op != nir_op_unpack_64_2x32_split_x && alu->op != nir_op_unpack_64_2x32_split_y)
                return false;
             if (!only_used_by_cross_lane_instrs(&alu->def, follow_phis))
                return false;
    
             continue;
          }
          case nir_instr_type_intrinsic: {
             nir_intrinsic_instr* intrin = nir_instr_as_intrinsic(nir_src_parent_instr(src));
             if (intrin->intrinsic != nir_intrinsic_read_invocation &&
                 intrin->intrinsic != nir_intrinsic_read_first_invocation &&
                 intrin->intrinsic != nir_intrinsic_lane_permute_16_amd)
                return false;
    
             continue;
          }
          case nir_instr_type_phi: {
             /* Don't follow more than 1 phis, this avoids infinite loops. */
             if (!follow_phis)
                return false;
    
             nir_phi_instr* phi = nir_instr_as_phi(nir_src_parent_instr(src));
             if (!only_used_by_cross_lane_instrs(&phi->def, false))
                return false;
    
             continue;
          }
          default: return false;
          }
       }
    
       return true;
    }
    
    /* If one side of a divergent IF ends in a branch and the other doesn't, we
     * might have to emit the contents of the side without the branch at the merge
     * block instead. This is so that we can use any SGPR live-out of the side
     * without the branch without creating a linear phi in the invert or merge block.
     *
     * This also removes any unreachable merge blocks.
     */
    bool
    sanitize_if(nir_function_impl* impl, nir_if* nif)
    {
       nir_block* then_block = nir_if_last_then_block(nif);
       nir_block* else_block = nir_if_last_else_block(nif);
       bool then_jump = nir_block_ends_in_jump(then_block);
       bool else_jump = nir_block_ends_in_jump(else_block);
       if (!then_jump && !else_jump)
          return false;
    
       /* If the continue from block is empty then return as there is nothing to
        * move.
        */
       if (nir_cf_list_is_empty_block(then_jump ? &nif->else_list : &nif->then_list))
          return false;
    
       /* Even though this if statement has a jump on one side, we may still have
        * phis afterwards.  Single-source phis can be produced by loop unrolling
        * or dead control-flow passes and are perfectly legal.  Run a quick phi
        * removal on the block after the if to clean up any such phis.
        */
       nir_remove_single_src_phis_block(nir_cf_node_as_block(nir_cf_node_next(&nif->cf_node)));
    
       /* Finally, move the continue from branch after the if-statement. */
       nir_block* last_continue_from_blk = then_jump ? else_block : then_block;
       nir_block* first_continue_from_blk =
          then_jump ? nir_if_first_else_block(nif) : nir_if_first_then_block(nif);
    
       /* We don't need to repair SSA. nir_remove_after_cf_node() replaces any uses with undef. */
       if (then_jump && else_jump)
          nir_remove_after_cf_node(&nif->cf_node);
    
       nir_cf_list tmp;
       nir_cf_extract(&tmp, nir_before_block(first_continue_from_blk),
                      nir_after_block(last_continue_from_blk));
       nir_cf_reinsert(&tmp, nir_after_cf_node(&nif->cf_node));
    
       return true;
    }
    
    bool
    sanitize_cf_list(nir_function_impl* impl, struct exec_list* cf_list)
    {
       bool progress = false;
       foreach_list_typed (nir_cf_node, cf_node, node, cf_list) {
          switch (cf_node->type) {
          case nir_cf_node_block: break;
          case nir_cf_node_if: {
             nir_if* nif = nir_cf_node_as_if(cf_node);
             progress |= sanitize_cf_list(impl, &nif->then_list);
             progress |= sanitize_cf_list(impl, &nif->else_list);
             progress |= sanitize_if(impl, nif);
             break;
          }
          case nir_cf_node_loop: {
             nir_loop* loop = nir_cf_node_as_loop(cf_node);
             assert(!nir_loop_has_continue_construct(loop));
             progress |= sanitize_cf_list(impl, &loop->body);
    
             /* NIR seems to allow this, and even though the loop exit has no predecessors, SSA defs from the
              * loop header are live. Handle this without complicating the ACO IR by creating a dummy break.
              */
             if (nir_cf_node_cf_tree_next(&loop->cf_node)->predecessors->entries == 0) {
                nir_builder b = nir_builder_create(impl);
                b.cursor = nir_after_block_before_jump(nir_loop_last_block(loop));
    
                nir_def *cond = nir_imm_false(&b);
                /* We don't use block divergence information, so just this is enough. */
                cond->divergent = false;
    
                nir_push_if(&b, cond);
                nir_jump(&b, nir_jump_break);
                nir_pop_if(&b, NULL);
    
                progress = true;
             }
             break;
          }
          case nir_cf_node_function: unreachable("Invalid cf type");
          }
       }
    
       return progress;
    }
    
    void
    apply_nuw_to_ssa(isel_context* ctx, nir_def* ssa)
    {
       nir_scalar scalar;
       scalar.def = ssa;
       scalar.comp = 0;
    
       if (!nir_scalar_is_alu(scalar) || nir_scalar_alu_op(scalar) != nir_op_iadd)
          return;
    
       nir_alu_instr* add = nir_instr_as_alu(ssa->parent_instr);
    
       if (add->no_unsigned_wrap)
          return;
    
       nir_scalar src0 = nir_scalar_chase_alu_src(scalar, 0);
       nir_scalar src1 = nir_scalar_chase_alu_src(scalar, 1);
    
       if (nir_scalar_is_const(src0)) {
          nir_scalar tmp = src0;
          src0 = src1;
          src1 = tmp;
       }
    
       uint32_t src1_ub = nir_unsigned_upper_bound(ctx->shader, ctx->range_ht, src1, &ctx->ub_config);
       add->no_unsigned_wrap =
          !nir_addition_might_overflow(ctx->shader, ctx->range_ht, src0, src1_ub, &ctx->ub_config);
    }
    
    void
    apply_nuw_to_offsets(isel_context* ctx, nir_function_impl* impl)
    {
       nir_foreach_block (block, impl) {
          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_constant:
             case nir_intrinsic_load_uniform:
             case nir_intrinsic_load_push_constant:
                if (!nir_src_is_divergent(&intrin->src[0]))
                   apply_nuw_to_ssa(ctx, intrin->src[0].ssa);
                break;
             case nir_intrinsic_load_ubo:
             case nir_intrinsic_load_ssbo:
                if (!nir_src_is_divergent(&intrin->src[1]))
                   apply_nuw_to_ssa(ctx, intrin->src[1].ssa);
                break;
             case nir_intrinsic_store_ssbo:
                if (!nir_src_is_divergent(&intrin->src[2]))
                   apply_nuw_to_ssa(ctx, intrin->src[2].ssa);
                break;
             case nir_intrinsic_load_scratch: apply_nuw_to_ssa(ctx, intrin->src[0].ssa); break;
             case nir_intrinsic_store_scratch:
             case nir_intrinsic_load_smem_amd: apply_nuw_to_ssa(ctx, intrin->src[1].ssa); break;
             default: break;
             }
          }
       }
    }
    
    RegClass
    get_reg_class(isel_context* ctx, RegType type, unsigned components, unsigned bitsize)
    {
       if (bitsize == 1)
          return RegClass(RegType::sgpr, ctx->program->lane_mask.size() * components);
       else
          return RegClass::get(type, components * bitsize / 8u);
    }
    
    void
    setup_tcs_info(isel_context* ctx)
    {
       ctx->tcs_in_out_eq = ctx->program->info.vs.tcs_in_out_eq;
       ctx->any_tcs_inputs_via_lds = ctx->program->info.vs.any_tcs_inputs_via_lds;
    }
    
    void
    setup_lds_size(isel_context* ctx, nir_shader* nir)
    {
       /* TCS and GFX9 GS are special cases, already in units of the allocation granule. */
       if (ctx->stage.has(SWStage::TCS))
          ctx->program->config->lds_size = ctx->program->info.tcs.num_lds_blocks;
       else if (ctx->stage.hw == AC_HW_LEGACY_GEOMETRY_SHADER && ctx->options->gfx_level >= GFX9)
          ctx->program->config->lds_size = ctx->program->info.gfx9_gs_ring_lds_size;
       else
          ctx->program->config->lds_size =
             DIV_ROUND_UP(nir->info.shared_size, ctx->program->dev.lds_encoding_granule);
    
       /* Make sure we fit the available LDS space. */
       assert((ctx->program->config->lds_size * ctx->program->dev.lds_encoding_granule) <=
              ctx->program->dev.lds_limit);
    }
    
    void
    setup_nir(isel_context* ctx, nir_shader* nir)
    {
       nir_convert_to_lcssa(nir, true, false);
       if (nir_lower_phis_to_scalar(nir, true)) {
          nir_copy_prop(nir);
          nir_opt_dce(nir);
       }
    
       nir_function_impl* func = nir_shader_get_entrypoint(nir);
       nir_index_ssa_defs(func);
    }
    
    /* Returns true if we can skip uniformization of a merge phi. This makes the destination divergent,
     * and so is only safe if the inconsistency it introduces into the divergence analysis won't break
     * code generation. If we unsafely skip uniformization, later instructions (such as SSBO loads,
     * some subgroup intrinsics and certain conversions) can use divergence analysis information which
     * is no longer correct.
     */
    bool
    skip_uniformize_merge_phi(nir_def* ssa, unsigned depth)
    {
       if (depth >= 16)
          return false;
    
       nir_foreach_use (src, ssa) {
          switch (nir_src_parent_instr(src)->type) {
          case nir_instr_type_alu: {
             nir_alu_instr* alu = nir_instr_as_alu(nir_src_parent_instr(src));
             if (alu->def.divergent)
                break;
    
             switch (alu->op) {
             case nir_op_f2i16:
             case nir_op_f2u16:
             case nir_op_f2i32:
             case nir_op_f2u32:
             case nir_op_b2i8:
             case nir_op_b2i16:
             case nir_op_b2i32:
             case nir_op_b2b32:
             case nir_op_b2f16:
             case nir_op_b2f32:
             case nir_op_b2f64:
             case nir_op_mov:
                /* These opcodes p_as_uniform or vote_any() the source, so fail immediately. We don't
                 * need to do this for non-nir_op_b2 if we know we'll move it back into a VGPR,
                 * in which case the p_as_uniform would be eliminated. This would be way too fragile,
                 * though.
                 */
                return false;
             default:
                if (!skip_uniformize_merge_phi(&alu->def, depth + 1))
                   return false;
                break;
             }
             break;
          }
          case nir_instr_type_intrinsic: {
             nir_intrinsic_instr* intrin = nir_instr_as_intrinsic(nir_src_parent_instr(src));
             unsigned src_idx = src - intrin->src;
             /* nir_intrinsic_lane_permute_16_amd is only safe because we don't use divergence analysis
              * for it's instruction selection. We use that intrinsic for NGG culling. All others are
              * stores with VGPR sources.
              */
             if (intrin->intrinsic == nir_intrinsic_lane_permute_16_amd ||
                 intrin->intrinsic == nir_intrinsic_export_amd ||
                 intrin->intrinsic == nir_intrinsic_export_dual_src_blend_amd ||
                 (intrin->intrinsic == nir_intrinsic_export_row_amd && src_idx == 0) ||
                 (intrin->intrinsic == nir_intrinsic_store_buffer_amd && src_idx == 0) ||
                 (intrin->intrinsic == nir_intrinsic_store_ssbo && src_idx == 0) ||
                 (intrin->intrinsic == nir_intrinsic_store_global && src_idx == 0) ||
                 (intrin->intrinsic == nir_intrinsic_store_scratch && src_idx == 0) ||
                 (intrin->intrinsic == nir_intrinsic_store_shared && src_idx == 0))
                break;
             return false;
          }
          case nir_instr_type_phi: {
             nir_phi_instr* phi = nir_instr_as_phi(nir_src_parent_instr(src));
             if (phi->def.divergent || skip_uniformize_merge_phi(&phi->def, depth + 1))
                break;
             return false;
          }
          case nir_instr_type_tex: {
             /* This is either used as a VGPR source or it's a (potentially undef) descriptor. */
             break;
          }
          default: {
             return false;
          }
          }
       }
    
       return true;
    }
    
    } /* end namespace */
    
    void
    init_context(isel_context* ctx, nir_shader* shader)
    {
       nir_function_impl* impl = nir_shader_get_entrypoint(shader);
       ctx->shader = shader;
    
       /* Init NIR range analysis. */
       ctx->range_ht = _mesa_pointer_hash_table_create(NULL);
       ctx->ub_config.min_subgroup_size = ctx->program->wave_size;
       ctx->ub_config.max_subgroup_size = ctx->program->wave_size;
       ctx->ub_config.max_workgroup_invocations = 2048;
       ctx->ub_config.max_workgroup_count[0] = 4294967295;
       ctx->ub_config.max_workgroup_count[1] = 65535;
       ctx->ub_config.max_workgroup_count[2] = 65535;
       ctx->ub_config.max_workgroup_size[0] = 1024;
       ctx->ub_config.max_workgroup_size[1] = 1024;
       ctx->ub_config.max_workgroup_size[2] = 1024;
    
       uint32_t options =
          shader->options->divergence_analysis_options | nir_divergence_ignore_undef_if_phi_srcs;
       nir_divergence_analysis_impl(impl, (nir_divergence_options)options);
       shader->info.divergence_analysis_run = true;
    
       apply_nuw_to_offsets(ctx, impl);
       ac_nir_flag_smem_for_loads(shader, ctx->program->gfx_level, false, true);
    
       /* sanitize control flow */
       sanitize_cf_list(impl, &impl->body);
       nir_metadata_preserve(impl, nir_metadata_none);
    
       /* we'll need these for isel */
       nir_metadata_require(impl, nir_metadata_block_index);
    
       if (ctx->options->dump_preoptir) {
          fprintf(stderr, "NIR shader before instruction selection:\n");
          nir_print_shader(shader, stderr);
       }
    
       ctx->first_temp_id = ctx->program->peekAllocationId();
       ctx->program->allocateRange(impl->ssa_alloc);
       RegClass* regclasses = ctx->program->temp_rc.data() + ctx->first_temp_id;
    
       /* TODO: make this recursive to improve compile times */
       bool done = false;
       while (!done) {
          done = true;
          nir_foreach_block (block, impl) {
             nir_foreach_instr (instr, block) {
                switch (instr->type) {
                case nir_instr_type_alu: {
                   nir_alu_instr* alu_instr = nir_instr_as_alu(instr);
                   RegType type = RegType::sgpr;
    
                   /* packed 16bit instructions have to be VGPR */
                   if (alu_instr->def.num_components == 2 &&
                       nir_op_infos[alu_instr->op].output_size == 0)
                      type = RegType::vgpr;
    
                   switch (alu_instr->op) {
                   case nir_op_f2i16:
                   case nir_op_f2u16:
                   case nir_op_f2i32:
                   case nir_op_f2u32:
                   case nir_op_mov:
                      if (alu_instr->def.divergent &&
                          regclasses[alu_instr->src[0].src.ssa->index].type() == RegType::vgpr)
                         type = RegType::vgpr;
                      break;
                   case nir_op_fmulz:
                   case nir_op_ffmaz:
                   case nir_op_f2f64:
                   case nir_op_u2f64:
                   case nir_op_i2f64:
                   case nir_op_pack_unorm_2x16:
                   case nir_op_pack_snorm_2x16:
                   case nir_op_pack_uint_2x16:
                   case nir_op_pack_sint_2x16:
                   case nir_op_ldexp:
                   case nir_op_frexp_sig:
                   case nir_op_frexp_exp:
                   case nir_op_cube_amd:
                   case nir_op_msad_4x8:
                   case nir_op_mqsad_4x8:
                   case nir_op_udot_4x8_uadd:
                   case nir_op_sdot_4x8_iadd:
                   case nir_op_sudot_4x8_iadd:
                   case nir_op_udot_4x8_uadd_sat:
                   case nir_op_sdot_4x8_iadd_sat:
                   case nir_op_sudot_4x8_iadd_sat:
                   case nir_op_udot_2x16_uadd:
                   case nir_op_sdot_2x16_iadd:
                   case nir_op_udot_2x16_uadd_sat:
                   case nir_op_sdot_2x16_iadd_sat:
                   case nir_op_alignbyte_amd: type = RegType::vgpr; break;
                   case nir_op_fmul:
                   case nir_op_ffma:
                   case nir_op_fadd:
                   case nir_op_fsub:
                   case nir_op_fmax:
                   case nir_op_fmin:
                   case nir_op_fsat:
                   case nir_op_fneg:
                   case nir_op_fabs:
                   case nir_op_fsign:
                   case nir_op_i2f16:
                   case nir_op_i2f32:
                   case nir_op_u2f16:
                   case nir_op_u2f32:
                   case nir_op_f2f16:
                   case nir_op_f2f16_rtz:
                   case nir_op_f2f16_rtne:
                   case nir_op_f2f32:
                   case nir_op_fquantize2f16:
                   case nir_op_ffract:
                   case nir_op_ffloor:
                   case nir_op_fceil:
                   case nir_op_ftrunc:
                   case nir_op_fround_even:
                   case nir_op_frcp:
                   case nir_op_frsq:
                   case nir_op_fsqrt:
                   case nir_op_fexp2:
                   case nir_op_flog2:
                   case nir_op_fsin_amd:
                   case nir_op_fcos_amd:
                   case nir_op_pack_half_2x16_rtz_split:
                   case nir_op_pack_half_2x16_split:
                   case nir_op_unpack_half_2x16_split_x:
                   case nir_op_unpack_half_2x16_split_y: {
                      if (ctx->program->gfx_level < GFX11_5 ||
                          alu_instr->src[0].src.ssa->bit_size > 32) {
                         type = RegType::vgpr;
                         break;
                      }
                      FALLTHROUGH;
                   }
                   default:
                      for (unsigned i = 0; i < nir_op_infos[alu_instr->op].num_inputs; i++) {
                         if (alu_instr->src[i].src.ssa->bit_size == 1
                                ? nir_src_is_divergent(&alu_instr->src[i].src)
                                : regclasses[alu_instr->src[i].src.ssa->index].type() == RegType::vgpr)
                            type = RegType::vgpr;
                      }
                      break;
                   }
    
                   RegClass rc =
                      get_reg_class(ctx, type, alu_instr->def.num_components, alu_instr->def.bit_size);
                   regclasses[alu_instr->def.index] = rc;
                   break;
                }
                case nir_instr_type_load_const: {
                   unsigned num_components = nir_instr_as_load_const(instr)->def.num_components;
                   unsigned bit_size = nir_instr_as_load_const(instr)->def.bit_size;
                   RegClass rc = get_reg_class(ctx, RegType::sgpr, num_components, bit_size);
                   regclasses[nir_instr_as_load_const(instr)->def.index] = rc;
                   break;
                }
                case nir_instr_type_intrinsic: {
                   nir_intrinsic_instr* intrinsic = nir_instr_as_intrinsic(instr);
                   if (!nir_intrinsic_infos[intrinsic->intrinsic].has_dest)
                      break;
                   if (intrinsic->intrinsic == nir_intrinsic_strict_wqm_coord_amd) {
                      regclasses[intrinsic->def.index] =
                         RegClass::get(RegType::vgpr, intrinsic->def.num_components * 4 +
                                                         nir_intrinsic_base(intrinsic))
                            .as_linear();
                      break;
                   }
                   RegType type = RegType::sgpr;
                   switch (intrinsic->intrinsic) {
                   case nir_intrinsic_load_push_constant:
                   case nir_intrinsic_load_workgroup_id:
                   case nir_intrinsic_load_num_workgroups:
                   case nir_intrinsic_load_sbt_base_amd:
                   case nir_intrinsic_load_subgroup_id:
                   case nir_intrinsic_load_num_subgroups:
                   case nir_intrinsic_vote_all:
                   case nir_intrinsic_vote_any:
                   case nir_intrinsic_read_first_invocation:
                   case nir_intrinsic_as_uniform:
                   case nir_intrinsic_read_invocation:
                   case nir_intrinsic_first_invocation:
                   case nir_intrinsic_ballot:
                   case nir_intrinsic_ballot_relaxed:
                   case nir_intrinsic_bindless_image_samples:
                   case nir_intrinsic_load_scalar_arg_amd:
                   case nir_intrinsic_load_lds_ngg_scratch_base_amd:
                   case nir_intrinsic_load_lds_ngg_gs_out_vertex_base_amd:
                   case nir_intrinsic_load_smem_amd:
                   case nir_intrinsic_unit_test_uniform_amd: type = RegType::sgpr; break;
                   case nir_intrinsic_load_input:
                   case nir_intrinsic_load_per_primitive_input:
                   case nir_intrinsic_load_output:
                   case nir_intrinsic_load_input_vertex:
                   case nir_intrinsic_load_per_vertex_input:
                   case nir_intrinsic_load_per_vertex_output:
                   case nir_intrinsic_load_interpolated_input:
                   case nir_intrinsic_write_invocation_amd:
                   case nir_intrinsic_mbcnt_amd:
                   case nir_intrinsic_lane_permute_16_amd:
                   case nir_intrinsic_dpp16_shift_amd:
                   case nir_intrinsic_ssbo_atomic:
                   case nir_intrinsic_ssbo_atomic_swap:
                   case nir_intrinsic_global_atomic_amd:
                   case nir_intrinsic_global_atomic_swap_amd:
                   case nir_intrinsic_bindless_image_atomic:
                   case nir_intrinsic_bindless_image_atomic_swap:
                   case nir_intrinsic_bindless_image_size:
                   case nir_intrinsic_shared_atomic:
                   case nir_intrinsic_shared_atomic_swap:
                   case nir_intrinsic_load_scratch:
                   case nir_intrinsic_load_typed_buffer_amd:
                   case nir_intrinsic_load_buffer_amd:
                   case nir_intrinsic_load_initial_edgeflags_amd:
                   case nir_intrinsic_gds_atomic_add_amd:
                   case nir_intrinsic_bvh64_intersect_ray_amd:
                   case nir_intrinsic_load_vector_arg_amd:
                   case nir_intrinsic_ordered_xfb_counter_add_gfx11_amd:
                   case nir_intrinsic_cmat_muladd_amd:
                   case nir_intrinsic_unit_test_divergent_amd: type = RegType::vgpr; break;
                   case nir_intrinsic_load_shared:
                   case nir_intrinsic_load_shared2_amd:
                      /* When the result of these loads is only used by cross-lane instructions,
                       * it is beneficial to use a VGPR destination. This is because this allows
                       * to put the s_waitcnt further down, which decreases latency.
                       */
                      if (only_used_by_cross_lane_instrs(&intrinsic->def)) {
                         type = RegType::vgpr;
                         break;
                      }
                      FALLTHROUGH;
                   case nir_intrinsic_shuffle:
                   case nir_intrinsic_quad_broadcast:
                   case nir_intrinsic_quad_swap_horizontal:
                   case nir_intrinsic_quad_swap_vertical:
                   case nir_intrinsic_quad_swap_diagonal:
                   case nir_intrinsic_quad_swizzle_amd:
                   case nir_intrinsic_masked_swizzle_amd:
                   case nir_intrinsic_rotate:
                   case nir_intrinsic_inclusive_scan:
                   case nir_intrinsic_exclusive_scan:
                   case nir_intrinsic_reduce:
                   case nir_intrinsic_load_ubo:
                   case nir_intrinsic_load_ssbo:
                   case nir_intrinsic_load_global_amd:
                      type = intrinsic->def.divergent ? RegType::vgpr : RegType::sgpr;
                      break;
                   case nir_intrinsic_ddx:
                   case nir_intrinsic_ddy:
                   case nir_intrinsic_ddx_fine:
                   case nir_intrinsic_ddy_fine:
                   case nir_intrinsic_ddx_coarse:
                   case nir_intrinsic_ddy_coarse: type = RegType::vgpr; break;
                   default:
                      for (unsigned i = 0; i < nir_intrinsic_infos[intrinsic->intrinsic].num_srcs;
                           i++) {
                         if (regclasses[intrinsic->src[i].ssa->index].type() == RegType::vgpr)
                            type = RegType::vgpr;
                      }
                      break;
                   }
                   RegClass rc =
                      get_reg_class(ctx, type, intrinsic->def.num_components, intrinsic->def.bit_size);
                   regclasses[intrinsic->def.index] = rc;
                   break;
                }
                case nir_instr_type_tex: {
                   nir_tex_instr* tex = nir_instr_as_tex(instr);
                   RegType type = tex->def.divergent ? RegType::vgpr : RegType::sgpr;
    
                   if (tex->op == nir_texop_texture_samples) {
                      assert(!tex->def.divergent);
                   }
    
                   RegClass rc = get_reg_class(ctx, type, tex->def.num_components, tex->def.bit_size);
                   regclasses[tex->def.index] = rc;
                   break;
                }
                case nir_instr_type_undef: {
                   unsigned num_components = nir_instr_as_undef(instr)->def.num_components;
                   unsigned bit_size = nir_instr_as_undef(instr)->def.bit_size;
                   RegClass rc = get_reg_class(ctx, RegType::sgpr, num_components, bit_size);
                   regclasses[nir_instr_as_undef(instr)->def.index] = rc;
                   break;
                }
                case nir_instr_type_phi: {
                   nir_phi_instr* phi = nir_instr_as_phi(instr);
                   RegType type = RegType::sgpr;
                   unsigned num_components = phi->def.num_components;
                   assert((phi->def.bit_size != 1 || num_components == 1) &&
                          "Multiple components not supported on boolean phis.");
    
                   if (phi->def.divergent) {
                      type = RegType::vgpr;
                   } else {
                      bool vgpr_src = false;
                      nir_foreach_phi_src (src, phi)
                         vgpr_src |= regclasses[src->src.ssa->index].type() == RegType::vgpr;
    
                      if (vgpr_src) {
                         type = RegType::vgpr;
    
                         /* This might be the case because of nir_divergence_ignore_undef_if_phi_srcs. */
                         bool divergent_merge = false;
                         if (nir_cf_node_prev(&block->cf_node) &&
                             nir_cf_node_prev(&block->cf_node)->type == nir_cf_node_if) {
                            nir_if* nif = nir_cf_node_as_if(nir_cf_node_prev(&block->cf_node));
                            divergent_merge = nir_src_is_divergent(&nif->condition);
                         }
    
                         /* In case of uniform phis after divergent merges, ensure that the dst is an
                          * SGPR and does not contain undefined values for some invocations.
                          */
                         if (divergent_merge && !skip_uniformize_merge_phi(&phi->def, 0))
                            type = RegType::sgpr;
                      }
                   }
    
                   RegClass rc = get_reg_class(ctx, type, num_components, phi->def.bit_size);
                   if (rc != regclasses[phi->def.index])
                      done = false;
                   regclasses[phi->def.index] = rc;
                   break;
                }
                default: break;
                }
             }
          }
       }
    
       ctx->program->config->spi_ps_input_ena = ctx->program->info.ps.spi_ps_input_ena;
       ctx->program->config->spi_ps_input_addr = ctx->program->info.ps.spi_ps_input_addr;
    
       /* align and copy constant data */
       while (ctx->program->constant_data.size() % 4u)
          ctx->program->constant_data.push_back(0);
       ctx->constant_data_offset = ctx->program->constant_data.size();
       ctx->program->constant_data.insert(ctx->program->constant_data.end(),
                                          (uint8_t*)shader->constant_data,
                                          (uint8_t*)shader->constant_data + shader->constant_data_size);
    
       BITSET_CLEAR_RANGE(ctx->output_args, 0, BITSET_SIZE(ctx->output_args));
    }
    
    void
    cleanup_context(isel_context* ctx)
    {
       _mesa_hash_table_destroy(ctx->range_ht, NULL);
    }
    
    isel_context
    setup_isel_context(Program* program, unsigned shader_count, struct nir_shader* const* shaders,
                       ac_shader_config* config, const struct aco_compiler_options* options,
                       const struct aco_shader_info* info, const struct ac_shader_args* args,
                       SWStage sw_stage)
    {
       for (unsigned i = 0; i < shader_count; i++) {
          switch (shaders[i]->info.stage) {
          case MESA_SHADER_VERTEX: sw_stage = sw_stage | SWStage::VS; break;
          case MESA_SHADER_TESS_CTRL: sw_stage = sw_stage | SWStage::TCS; break;
          case MESA_SHADER_TESS_EVAL: sw_stage = sw_stage | SWStage::TES; break;
          case MESA_SHADER_GEOMETRY: sw_stage = sw_stage | SWStage::GS; break;
          case MESA_SHADER_FRAGMENT: sw_stage = sw_stage | SWStage::FS; break;
          case MESA_SHADER_KERNEL:
          case MESA_SHADER_COMPUTE: sw_stage = sw_stage | SWStage::CS; break;
          case MESA_SHADER_TASK: sw_stage = sw_stage | SWStage::TS; break;
          case MESA_SHADER_MESH: sw_stage = sw_stage | SWStage::MS; break;
          case MESA_SHADER_RAYGEN:
          case MESA_SHADER_CLOSEST_HIT:
          case MESA_SHADER_MISS:
          case MESA_SHADER_CALLABLE:
          case MESA_SHADER_INTERSECTION:
          case MESA_SHADER_ANY_HIT: sw_stage = SWStage::RT; break;
          default: unreachable("Shader stage not implemented");
          }
       }
    
       init_program(program, Stage{info->hw_stage, sw_stage}, info, options->gfx_level, options->family,
                    options->wgp_mode, config);
    
       isel_context ctx = {};
       ctx.program = program;
       ctx.args = args;
       ctx.options = options;
       ctx.stage = program->stage;
    
       program->workgroup_size = program->info.workgroup_size;
       assert(program->workgroup_size);
    
       /* Mesh shading only works on GFX10.3+. */
       ASSERTED bool mesh_shading = ctx.stage.has(SWStage::TS) || ctx.stage.has(SWStage::MS);
       assert(!mesh_shading || ctx.program->gfx_level >= GFX10_3);
    
       setup_tcs_info(&ctx);
    
       calc_min_waves(program);
    
       unsigned scratch_size = 0;
       for (unsigned i = 0; i < shader_count; i++) {
          nir_shader* nir = shaders[i];
          setup_nir(&ctx, nir);
          setup_lds_size(&ctx, nir);
       }
    
       for (unsigned i = 0; i < shader_count; i++)
          scratch_size = std::max(scratch_size, shaders[i]->scratch_size);
    
       ctx.program->config->scratch_bytes_per_wave = scratch_size * ctx.program->wave_size;
    
       unsigned nir_num_blocks = 0;
       for (unsigned i = 0; i < shader_count; i++)
          nir_num_blocks += nir_shader_get_entrypoint(shaders[i])->num_blocks;
       ctx.program->blocks.reserve(nir_num_blocks * 2);
       ctx.block = ctx.program->create_and_insert_block();
       ctx.block->kind = block_kind_top_level;
    
       return ctx;
    }
    
    } // namespace aco