Break typecheck dependency in escape analysis.

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 5550 matching lines @@
   DECLARE_INSTRUCTION_FACTORY_P3(HLoadNamedField, HValue*, HObjectAccess,
                                  HValue*);
 
   HValue* object() { return OperandAt(0); }
   HValue* typecheck() {
     ASSERT(HasTypeCheck());
     return OperandAt(1);
   }
 
   bool HasTypeCheck() const { return OperandAt(0) != OperandAt(1); }
+  void clear_typecheck() { SetOperandAt(1, object()); }

[Michael Starzinger, 2013/08/12 09:22:09]

nit: Can we name this "ClearTypeCheck" instead?

   HObjectAccess access() const { return access_; }
   Representation field_representation() const {
       return access_.representation();
   }
 
   virtual bool HasEscapingOperandAt(int index) { return false; }
   virtual Representation RequiredInputRepresentation(int index) {
     if (index == 0 && access().IsExternalMemory()) {
       // object must be external in case of external memory access
       return Representation::External();
@@ skipping 1184 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_