Use CommonNodeCache for heap constants in ChangeLowering.

src/compiler/change-lowering.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/change-lowering.h"
 
 #include "src/compiler/common-node-cache.h"
 #include "src/compiler/graph.h"
 
 namespace v8 {
@@ skipping 16 matching lines @@
 Node* ChangeLoweringBase::ExternalConstant(ExternalReference reference) {
   Node** loc = cache()->FindExternalConstant(reference);
   if (*loc == NULL) {
     *loc = graph()->NewNode(common()->ExternalConstant(reference));
   }
   return *loc;
 }
 
 
 Node* ChangeLoweringBase::HeapConstant(PrintableUnique<HeapObject> value) {
-  // TODO(bmeurer): Use common node cache.
-  return graph()->NewNode(common()->HeapConstant(value));
+  Node** loc = cache()->FindHeapConstant(value);
+  if (*loc == NULL) {
+    *loc = graph()->NewNode(common()->HeapConstant(value));
+  }
+  return *loc;
 }
 
 
 Node* ChangeLoweringBase::ImmovableHeapConstant(Handle<HeapObject> value) {
   return HeapConstant(
       PrintableUnique<HeapObject>::CreateImmovable(graph()->zone(), value));
 }
 
 
 Node* ChangeLoweringBase::Int32Constant(int32_t value) {
@@ skipping 202 matching lines @@
   return Replace(phi);
 }
 
 
 template class ChangeLowering<4>;
 template class ChangeLowering<8>;
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8