Optimize %IsConstructCall() on IA-32.

src/messages.js

 // 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 641 matching lines @@
     %FunctionSetPrototype(ErrorPrototype, $Object.prototype);
     %FunctionSetInstanceClassName(ErrorPrototype, 'Error');
     %FunctionSetPrototype(f, new ErrorPrototype());
   } else {
     %FunctionSetPrototype(f, new $Error());
   }
   %FunctionSetInstanceClassName(f, 'Error');
   %SetProperty(f.prototype, 'constructor', f, DONT_ENUM);
   f.prototype.name = name;
   %SetCode(f, function(m) {
-    if (%IsConstructCall()) {
+    if (%_IsConstructCall()) {
       if (m === kAddMessageAccessorsMarker) {
         DefineOneShotAccessor(this, 'message', function (obj) {
           return FormatMessage({type: obj.type, args: obj.arguments});
         });
       } else if (!IS_UNDEFINED(m)) {
         this.message = ToString(m);
       }
     } else {
       return new f(m);
     }
@@ skipping 19 matching lines @@
     return this.name + ": " + FormatMessage({ type: type, args: this.arguments });
   }
   var message = this.message;
   return this.name + (message ? (": " + message) : "");
 }, DONT_ENUM);
 
 
 // Boilerplate for exceptions for stack overflows. Used from
 // Top::StackOverflow().
 const kStackOverflowBoilerplate = MakeRangeError('stack_overflow', []);