Experimental: tiny change to enable using the shorter byte-register test...

src/codegen-ia32.cc

 // Copyright 2006-2008 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 1012 matching lines @@
         deferred = new DeferredInlineSmiAdd(this, smi_value, overwrite_mode);
       } else {
         deferred = new DeferredInlineSmiAddReversed(this, smi_value,
                                                     overwrite_mode);
       }
       Result operand = frame_->Pop();
       operand.ToRegister();
       frame_->Spill(operand.reg());
       __ add(Operand(operand.reg()), Immediate(value));
       deferred->enter()->Branch(overflow, &operand, not_taken);
-      __ test(Operand(operand.reg()), Immediate(kSmiTagMask));
+      __ test(operand.reg(), Immediate(kSmiTagMask));
       deferred->enter()->Branch(not_zero, &operand, not_taken);
       deferred->BindExit(&operand);
       frame_->Push(&operand);
       break;
     }
 
     case Token::SUB: {
       DeferredCode* deferred = NULL;
       Result operand = frame_->Pop();
       Result answer(this);  // Only allocated a new register if reversed.
@@ skipping 5499 matching lines @@
 
   // Slow-case: Go through the JavaScript implementation.
   __ bind(&slow);
   __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_FUNCTION);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal