Fix uninitialized variable compiler errors [GCC 4.8.4]

src/compiler/ast-graph-builder.cc

 // Copyright 2014 the V8 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 "src/compiler/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/js-type-feedback.h"
@@ skipping 2198 matching lines @@
 
 void AstGraphBuilder::VisitThrow(Throw* expr) {
   VisitForValue(expr->exception());
   Node* exception = environment()->Pop();
   Node* value = BuildThrowError(exception, expr->id());
   ast_context()->ProduceValue(value);
 }
 
 
 void AstGraphBuilder::VisitProperty(Property* expr) {
-  Node* value;
+  Node* value = nullptr;
   LhsKind property_kind = Property::GetAssignType(expr);
   VectorSlotPair pair = CreateVectorSlotPair(expr->PropertyFeedbackSlot());
   switch (property_kind) {
     case VARIABLE:
       UNREACHABLE();
-      value = nullptr;
       break;
     case NAMED_PROPERTY: {
       VisitForValue(expr->obj());
       FrameStateBeforeAndAfter states(this, expr->obj()->id());
       Node* object = environment()->Pop();
       Handle<Name> name = expr->key()->AsLiteral()->AsPropertyName();
       value = BuildNamedLoad(object, name, pair);
       states.AddToNode(value, expr->id(), ast_context()->GetStateCombine());
       break;
     }
@@ skipping 1803 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8