Prune unreferenced variables with a constructor initializer

src/compiler/translator/IntermNode.cpp

@@ -522,7 +522,13 @@ const char *TIntermAggregate::functionName() const
 
 bool TIntermAggregate::hasSideEffects() const
 {
-    if (isFunctionCall() && mFunction != nullptr && mFunction->isKnownToNotHaveSideEffects())
+    if (getQualifier() == EvqConst)
+    {
+        return false;
+    }
+    bool calledFunctionHasNoSideEffects =
+        isFunctionCall() && mFunction != nullptr && mFunction->isKnownToNotHaveSideEffects();
+    if (calledFunctionHasNoSideEffects || isConstructor())
     {
         for (TIntermNode *arg : mArguments)
         {

src/compiler/translator/RemoveUnreferencedVariables.cpp

@@ -177,7 +177,17 @@ void RemoveUnreferencedVariablesTraverser::removeVariableDeclaration(TIntermDecl
     if (declarator->getType().isStructSpecifier() && !declarator->getType().isNamelessStruct())
     {
         unsigned int structId = declarator->getType().getStruct()->uniqueId().get();
-        if ((*mStructIdRefCounts)[structId] > 1u)
+        unsigned int structRefCountInThisDeclarator = 1u;
+        if (declarator->getAsBinaryNode() &&
+            declarator->getAsBinaryNode()->getRight()->getAsAggregate())
+        {
+            ASSERT(declarator->getAsBinaryNode()->getLeft()->getType().getStruct() ==
+                   declarator->getType().getStruct());
+            ASSERT(declarator->getAsBinaryNode()->getRight()->getType().getStruct() ==
+                   declarator->getType().getStruct());
+            structRefCountInThisDeclarator = 2u;
+        }
+        if ((*mStructIdRefCounts)[structId] > structRefCountInThisDeclarator)
         {
             // If this declaration declares a named struct type that is used elsewhere, we need to
             // keep it. We can still change the declarator though so that it doesn't declare an
@@ -272,7 +282,7 @@ void RemoveUnreferencedVariablesTraverser::visitSymbol(TIntermSymbol *node)
 
 bool RemoveUnreferencedVariablesTraverser::visitAggregate(Visit visit, TIntermAggregate *node)
 {
-    if (mRemoveReferences)
+    if (visit == PreVisit && mRemoveReferences)
     {
         decrementStructTypeRefCount(node->getType());
     }

src/tests/compiler_tests/ConstantFolding_test.cpp

@@ -175,7 +175,7 @@ TEST_F(ConstantFoldingTest, Fold3x3MatrixInverse)
         "                                23.0f, 29.0f, 31.0f,\n"
         "                                37.0f, 41.0f, 43.0f));\n"
         "   mat3 m = m3 * mat3(i);\n"
-        "   my_Vec = m3[0];\n"
+        "   my_Vec = m[0];\n"
         "}\n";
     compileAssumeSuccess(shaderString);
     float inputElements[] =

src/tests/compiler_tests/RemoveUnreferencedVariables_test.cpp

@@ -686,3 +686,29 @@ TEST_F(RemoveUnreferencedVariablesTest, UserDefinedTypeInUniformBlock)
 
     ASSERT_TRUE(foundInCode("struct _umyStructType"));
 }
+
+// Test that a struct type that is referenced from an initializer with a constructor can be removed.
+TEST_F(RemoveUnreferencedVariablesTest, UserDefinedTypeConstructorInitializer)
+{
+    const std::string &shaderString =
+        R"(#version 300 es
+
+        precision highp float;
+        out vec4 my_FragColor;
+
+        struct myStructType
+        {
+            int iMember;
+        };
+
+        uniform int ui;
+
+        void main()
+        {
+            myStructType S = myStructType(ui);
+            my_FragColor = vec4(0, 1, 0, 1);
+        })";
+    compile(shaderString);
+
+    ASSERT_TRUE(notFoundInCode("myStructType"));
+}