Use 1 byte push REG instructions instead of the 2 byte ModRM version.

src/builtins-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 639 matching lines @@
   __ push(Immediate(ArgumentsAdaptorFrame::SENTINEL));
 
   // Push the function on the stack.
   __ push(edi);
 
   // Preserve the number of arguments on the stack. Must preserve both
   // eax and ebx because these registers are used when copying the
   // arguments and the receiver.
   ASSERT(kSmiTagSize == 1);
   __ lea(ecx, Operand(eax, eax, times_1, kSmiTag));
-  __ push(Operand(ecx));
+  __ push(ecx);
 }
 
 
 static void LeaveArgumentsAdaptorFrame(MacroAssembler* masm) {
   // Retrieve the number of arguments from the stack.
   __ mov(ebx, Operand(ebp, ArgumentsAdaptorFrameConstants::kLengthOffset));
 
   // Leave the frame.
   __ leave();
 
@@ skipping 222 matching lines @@
   // Register state for stub CallFunction (from CallFunctionStub in ic-ia32.cc).
   // ----------- S t a t e -------------
   //  No registers used on entry.
   // -----------------------------------
   Generate_DebugBreakCallHelper(masm, 0, false);
 }
 
 #undef __
 
 } }  // namespace v8::internal