Get rid of the HInstanceSize instruction.

src/code-stubs-hydrogen.cc

 // 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 416 matching lines @@
 }
 
 
 Handle<Code> FastCloneShallowArrayStub::GenerateCode(Isolate* isolate) {
   return DoGenerateCode(isolate, this);
 }
 
 
 template <>
 HValue* CodeStubGraphBuilder<FastCloneShallowObjectStub>::BuildCodeStub() {
-  Zone* zone = this->zone();
   HValue* undefined = graph()->GetConstantUndefined();
 
   HInstruction* boilerplate = Add<HLoadKeyed>(GetParameter(0),
                                               GetParameter(1),
                                               static_cast<HValue*>(NULL),
                                               FAST_ELEMENTS);
 
   IfBuilder checker(this);
   checker.IfNot<HCompareObjectEqAndBranch, HValue*>(boilerplate,
                                                     undefined);
   checker.And();
 
   int size = JSObject::kHeaderSize + casted_stub()->length() * kPointerSize;
-  HValue* boilerplate_size =
-      AddInstruction(new(zone) HInstanceSize(boilerplate));
+  HValue* boilerplate_map = Add<HLoadNamedField>(
+      boilerplate, HObjectAccess::ForMap());
+  HValue* boilerplate_size = Add<HLoadNamedField>(
+      boilerplate_map, HObjectAccess::ForMapInstanceSize());
   HValue* size_in_words = Add<HConstant>(size >> kPointerSizeLog2);
   checker.If<HCompareNumericAndBranch>(boilerplate_size,
                                        size_in_words, Token::EQ);
   checker.Then();
 
   HValue* size_in_bytes = Add<HConstant>(size);
 
   HInstruction* object = Add<HAllocate>(size_in_bytes, HType::JSObject(),
       isolate()->heap()->GetPretenureMode(), JS_OBJECT_TYPE);
 
@@ skipping 673 matching lines @@
   return js_function;
 }
 
 
 Handle<Code> FastNewClosureStub::GenerateCode(Isolate* isolate) {
   return DoGenerateCode(isolate, this);
 }
 
 
 } }  // namespace v8::internal