Elide unnecessary context reload in generated stubs.

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 1153 matching lines @@
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CompareMap)
 
  private:
   Handle<Map> map_;
 };
 
 
-class HReturn: public HTemplateControlInstruction<0, 1> {
+class HReturn: public HTemplateControlInstruction<0, 2> {
  public:
-  explicit HReturn(HValue* value) {
+  HReturn(HValue* value, HValue* context) {
     SetOperandAt(0, value);
+    SetOperandAt(1, context);
   }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
 
   virtual void PrintDataTo(StringStream* stream);
 
   HValue* value() { return OperandAt(0); }
+  HValue* context() { return OperandAt(1); }
 
   DECLARE_CONCRETE_INSTRUCTION(Return)
 };
 
 
 class HAbnormalExit: public HTemplateControlInstruction<0, 0> {
  public:
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::None();
   }
@@ skipping 4245 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_