Fix VectorizeVectorScalarArithmetic statement insertion

src/compiler/translator/IntermTraverse.cpp

@@ -122,6 +122,15 @@ TIntermTraverser::~TIntermTraverser()
 {
 }
 
+const TIntermBlock *TIntermTraverser::getParentBlock() const
+{
+    if (!mParentBlockStack.empty())
+    {
+        return mParentBlockStack.back().node;
+    }
+    return nullptr;
+}
+
 void TIntermTraverser::pushParentBlock(TIntermBlock *node)
 {
     mParentBlockStack.push_back(ParentBlock(node, 0));

src/compiler/translator/IntermTraverse.h

@@ -143,6 +143,8 @@ class TIntermTraverser : angle::NonCopyable
         return nullptr;
     }
 
+    const TIntermBlock *getParentBlock() const;
+
     void pushParentBlock(TIntermBlock *node);
     void incrementParentBlockPos();
     void popParentBlock();

src/compiler/translator/VectorizeVectorScalarArithmetic.cpp

@@ -11,6 +11,8 @@
 
 #include "compiler/translator/VectorizeVectorScalarArithmetic.h"
 
+#include <set>
+
 #include "compiler/translator/IntermNode.h"
 #include "compiler/translator/IntermTraverse.h"
 
@@ -29,7 +31,11 @@ class VectorizeVectorScalarArithmeticTraverser : public TIntermTraverser
     }
 
     bool didReplaceScalarsWithVectors() { return mReplaced; }
-    void nextIteration() { mReplaced = false; }
+    void nextIteration()
+    {
+        mReplaced = false;
+        mModifiedBlocks.clear();
+    }
 
   protected:
     bool visitBinary(Visit visit, TIntermBinary *node) override;
@@ -47,6 +53,7 @@ class VectorizeVectorScalarArithmeticTraverser : public TIntermTraverser
                                    TIntermTraverser::OriginalNode *originalNodeFate);
 
     bool mReplaced;
+    std::set<const TIntermBlock *> mModifiedBlocks;
 };
 
 TIntermTyped *VectorizeVectorScalarArithmeticTraverser::Vectorize(
@@ -241,11 +248,17 @@ bool VectorizeVectorScalarArithmeticTraverser::visitAggregate(Visit /*visit*/,
             // leave that be.
             if (!argBinary->getLeft()->hasSideEffects())
             {
-                replaceAssignInsideConstructor(node, argBinary);
-                mReplaced = true;
-                // Don't replace more nodes in the same subtree on this traversal.
-                // However, nodes elsewhere in the tree may still be replaced.
-                return false;
+                const TIntermBlock *parentBlock = getParentBlock();
+                // We can't do more than one insertion to the same block on the same traversal.
+                if (mModifiedBlocks.find(parentBlock) == mModifiedBlocks.end())
+                {
+                    replaceAssignInsideConstructor(node, argBinary);
+                    mModifiedBlocks.insert(parentBlock);
+                    mReplaced = true;
+                    // Don't replace more nodes in the same subtree on this traversal.
+                    // However, nodes elsewhere in the tree may still be replaced.
+                    return false;
+                }
             }
             break;
         }

src/tests/angle_unittests.gypi

@@ -88,6 +88,7 @@
             '<(angle_path)/src/tests/compiler_tests/ShCompile_test.cpp',
             '<(angle_path)/src/tests/compiler_tests/TypeTracking_test.cpp',
             '<(angle_path)/src/tests/compiler_tests/VariablePacker_test.cpp',
+            '<(angle_path)/src/tests/compiler_tests/VectorizeVectorScalarArithmetic_test.cpp',
             '<(angle_path)/src/tests/compiler_tests/WEBGL_multiview_test.cpp',
             '<(angle_path)/src/tests/compiler_tests/WorkGroupSize_test.cpp',
             '<(angle_path)/src/tests/preprocessor_tests/char_test.cpp',

src/tests/compiler_tests/VectorizeVectorScalarArithmetic_test.cpp

+//
+// Copyright (c) 2017 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.
+//
+// VectorizeVectorScalarArithmetic_test.cpp:
+//  Tests shader compilation with SH_REWRITE_VECTOR_SCALAR_ARITHMETIC workaround on.
+
+#include "GLSLANG/ShaderLang.h"
+#include "angle_gl.h"
+#include "gtest/gtest.h"
+#include "tests/test_utils/ShaderCompileTreeTest.h"
+
+using namespace sh;
+
+class VectorizeVectorScalarArithmeticTest : public ShaderCompileTreeTest
+{
+  public:
+    VectorizeVectorScalarArithmeticTest() : ShaderCompileTreeTest()
+    {
+        mExtraCompileOptions = SH_REWRITE_VECTOR_SCALAR_ARITHMETIC;
+    }
+
+  protected:
+    ::GLenum getShaderType() const override { return GL_FRAGMENT_SHADER; }
+    ShShaderSpec getShaderSpec() const override { return SH_GLES3_1_SPEC; }
+};
+
+// Test that two ops that generate statements in the parent block inside the same statement don't
+// trigger an assert.
+TEST_F(VectorizeVectorScalarArithmeticTest, TwoMutatedOpsWithSideEffectsInsideSameStatement)
+{
+    const std::string &shaderString =
+        R"(#version 300 es
+        precision highp float;
+
+        out vec4 res;
+        uniform float uf;
+
+        void main()
+        {
+            res = vec4(0.0);
+            float f = uf;
+            res += f *= f, res += f *= f;
+        })";
+    if (!compile(shaderString))
+    {
+        FAIL() << "Shader compilation failed, expecting success:\n" << mInfoLog;
+    }
+}