Optimize the equality check case of ICCompare stubs.

src/ic.h

 // Copyright 2011 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 692 matching lines @@
 
 class CompareIC: public IC {
  public:
   enum State {
     UNINITIALIZED,
     SMIS,
     HEAP_NUMBERS,
     SYMBOLS,
     STRINGS,
     OBJECTS,
+    KNOWN_OBJECTS,
     GENERIC
   };
 
   CompareIC(Isolate* isolate, Token::Value op)
       : IC(EXTRA_CALL_FRAME, isolate), op_(op) { }
 
   // Update the inline cache for the given operands.
   void UpdateCaches(Handle<Object> x, Handle<Object> y);
 
   // Factory method for getting an uninitialized compare stub.
@@ skipping 26 matching lines @@
   void patch(Code* code);
 };
 
 
 // Helper for BinaryOpIC and CompareIC.
 void PatchInlinedSmiCode(Address address);
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_H_