Fix field type handling in load elimination.

src/hydrogen-instructions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2752 matching lines @@
     return Representation::Tagged();
   }
   virtual bool HandleSideEffectDominator(GVNFlag side_effect,
                                          HValue* dominator) V8_OVERRIDE;
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   HValue* value() { return OperandAt(0); }
   HValue* typecheck() { return OperandAt(1); }
 
   Unique<Map> first_map() const { return map_set_.at(0); }
-  UniqueSet<Map> map_set() const { return map_set_; }
+  const UniqueSet<Map>* map_set() const { return &map_set_; }
 
   void set_map_set(UniqueSet<Map>* maps, Zone *zone) {
     map_set_.Clear();
     for (int i = 0; i < maps->size(); i++) {
       map_set_.Add(maps->at(i), zone);
     }
   }
 
   bool has_migration_target() const {
     return has_migration_target_;
@@ skipping 3381 matching lines @@
   HValue* dependency() {
     ASSERT(HasDependency());
     return OperandAt(1);
   }
   bool HasDependency() const { return OperandAt(0) != OperandAt(1); }
   HObjectAccess access() const { return access_; }
   Representation field_representation() const {
       return access_.representation();
   }
 
-  UniqueSet<Map> map_set() const { return map_set_; }
+  const UniqueSet<Map>* map_set() const { return &map_set_; }
 
   virtual bool HasEscapingOperandAt(int index) V8_OVERRIDE { return false; }
   virtual bool HasOutOfBoundsAccess(int size) V8_OVERRIDE {
     return !access().IsInobject() || access().offset() >= size;
   }
   virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     if (index == 0 && access().IsExternalMemory()) {
       // object must be external in case of external memory access
       return Representation::External();
     }
@@ skipping 1375 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_