Remove the HValueOf instruction.

src/hydrogen.cc

 // Copyright 2013 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 10295 matching lines @@
 void HOptimizedGraphBuilder::GenerateClassOf(CallRuntime* call) {
   // The special form detected by IsClassOfTest is detected before we get here
   // and does not cause a bailout.
   return Bailout(kInlinedRuntimeFunctionClassOf);
 }
 
 
 void HOptimizedGraphBuilder::GenerateValueOf(CallRuntime* call) {
   ASSERT(call->arguments()->length() == 1);
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
-  HValue* value = Pop();
-  HValueOf* result = New<HValueOf>(value);
-  return ast_context()->ReturnInstruction(result, call->id());
+  HValue* object = Pop();
+
+  IfBuilder if_objectisvalue(this);
+  HValue* objectisvalue = if_objectisvalue.If<HHasInstanceTypeAndBranch>(
+      object, JS_VALUE_TYPE);
+  if_objectisvalue.Then();
+  {
+    // Return the actual value.
+    Push(Add<HLoadNamedField>(
+            object, objectisvalue,
+            HObjectAccess::ForJSObjectOffset(JSValue::kValueOffset)));
+    Add<HSimulate>(call->id(), FIXED_SIMULATE);
+  }
+  if_objectisvalue.Else();
+  {
+    // If the object is not a value return the object.
+    Push(object);
+    Add<HSimulate>(call->id(), FIXED_SIMULATE);
+  }
+  if_objectisvalue.End();
+  return ast_context()->ReturnValue(Pop());
 }
 
 
 void HOptimizedGraphBuilder::GenerateDateField(CallRuntime* call) {
   ASSERT(call->arguments()->length() == 2);
   ASSERT_NE(NULL, call->arguments()->at(1)->AsLiteral());
   Smi* index = Smi::cast(*(call->arguments()->at(1)->AsLiteral()->value()));
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
   HValue* date = Pop();
   HDateField* result = New<HDateField>(date, index);
@@ skipping 912 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal