kc3-lang/angle/src/compiler/translator/RewriteUnaryMinusOperatorFloat.cpp

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• Author : Qiankun Miao
  Date : 2016-12-07 13:39:15
  Hash : f52fe93d
  Message : Work around unary minus operator float issue on Intel Mac 10.11 Result of -float is wrong on Intel Mac 10.11 drivers. Replace -float with 0.0 - float to work around this issue. BUG=308366 BUG=672380 Change-Id: I53bc2eda7259fff5805bec39896fc7b7a6eaf665 Reviewed-on: https://chromium-review.googlesource.com/417169 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>

• src/compiler/translator/RewriteUnaryMinusOperatorFloat.cpp

• //
  // Copyright (c) 2016 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  
  #include "compiler/translator/RewriteUnaryMinusOperatorFloat.h"
  
  #include "compiler/translator/IntermNode.h"
  
  namespace sh
  {
  
  namespace
  {
  
  class Traverser : public TIntermTraverser
  {
    public:
      static void Apply(TIntermNode *root);
  
    private:
      Traverser();
      bool visitUnary(Visit visit, TIntermUnary *node) override;
      void nextIteration();
  
      bool mFound = false;
  };
  
  // static
  void Traverser::Apply(TIntermNode *root)
  {
      Traverser traverser;
      do
      {
          traverser.nextIteration();
          root->traverse(&traverser);
          if (traverser.mFound)
          {
              traverser.updateTree();
          }
      } while (traverser.mFound);
  }
  
  Traverser::Traverser() : TIntermTraverser(true, false, false)
  {
  }
  
  void Traverser::nextIteration()
  {
      mFound = false;
  }
  
  bool Traverser::visitUnary(Visit visit, TIntermUnary *node)
  {
      if (mFound)
      {
          return false;
      }
  
      // Detect if the current operator is unary minus operator.
      if (node->getOp() != EOpNegative)
      {
          return true;
      }
  
      // Detect if the current operand is a float variable.
      TIntermTyped *fValue = node->getOperand();
      if (!fValue->getType().isScalarFloat())
      {
          return true;
      }
  
      // 0.0 - float
      TIntermTyped *zero = TIntermTyped::CreateZero(fValue->getType());
      zero->setLine(fValue->getLine());
      TIntermBinary *sub = new TIntermBinary(EOpSub, zero, fValue);
      sub->setLine(fValue->getLine());
  
      queueReplacement(node, sub, OriginalNode::IS_DROPPED);
  
      mFound = true;
      return false;
  }
  
  }  // anonymous namespace
  
  void RewriteUnaryMinusOperatorFloat(TIntermNode *root)
  {
      Traverser::Apply(root);
  }
  
  }  // namespace sh