Don't do a smi check twice in the TO_INTEGER macro.

src/macros.py

 # Copyright 2006-2009 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 102 matching lines @@
 macro FLOOR(arg)                = $floor(arg);
 
 # Macro for ECMAScript 5 queries of the type:
 # "Type(O) is object."
 # This is the same as being either a function or an object in V8 terminology.
 # In addition, an undetectable object is also included by this.
 macro IS_SPEC_OBJECT(arg) = (%_IsSpecObject(arg));
 
 # Inline macros. Use %IS_VAR to make sure arg is evaluated only once.
 macro NUMBER_IS_NAN(arg) = (!%_IsSmi(%IS_VAR(arg)) && !(arg == arg));
-macro TO_INTEGER(arg) = (%_IsSmi(%IS_VAR(arg)) ? arg : ToInteger(arg));
+macro TO_INTEGER(arg) = (%_IsSmi(%IS_VAR(arg)) ? arg : %NumberToInteger(ToNumber(arg)));
 macro TO_INTEGER_MAP_MINUS_ZERO(arg) = (%_IsSmi(%IS_VAR(arg)) ? arg : %NumberToIntegerMapMinusZero(ToNumber(arg)));
 macro TO_INT32(arg) = (%_IsSmi(%IS_VAR(arg)) ? arg : (arg >> 0));
 macro TO_UINT32(arg) = (arg >>> 0);
 macro TO_STRING_INLINE(arg) = (IS_STRING(%IS_VAR(arg)) ? arg : NonStringToString(arg));
 
 
 # Macros implemented in Python.
 python macro CHAR_CODE(str) = ord(str[1]);
 
 # Constants used on an array to implement the properties of the RegExp object.
@@ skipping 34 matching lines @@
 
 # PropertyDescriptor return value indices - must match 
 # PropertyDescriptorIndices in runtime.cc.
 const IS_ACCESSOR_INDEX = 0;
 const VALUE_INDEX = 1;
 const GETTER_INDEX = 2;
 const SETTER_INDEX = 3;
 const WRITABLE_INDEX = 4;
 const ENUMERABLE_INDEX = 5;
 const CONFIGURABLE_INDEX = 6;