Optimize isFinite and isNaN.

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 104 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 NUMBER_IS_FINITE(arg) = (%_IsSmi(%IS_VAR(arg)) || arg - arg == 0);
+macro NUMBER_IS_FINITE(arg) = (%_IsSmi(%IS_VAR(arg)) || ((arg == arg) && (arg != 1/0) && (arg != -1/0)));
 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));
 macro TO_NUMBER_INLINE(arg) = (IS_NUMBER(%IS_VAR(arg)) ? arg : NonNumberToNumber(arg));
 macro TO_OBJECT_INLINE(arg) = (IS_SPEC_OBJECT(%IS_VAR(arg)) ? arg : ToObject(arg));
 macro JSON_NUMBER_TO_STRING(arg) = ((%_IsSmi(%IS_VAR(arg)) || arg - arg == 0) ? %_NumberToString(arg) : "null");
 
 # Macros implemented in Python.
@@ skipping 50 matching lines @@
 const TYPE_EXTENSION = 1;
 const TYPE_NORMAL = 2;
 
 # Matches Script::CompilationType from objects.h
 const COMPILATION_TYPE_HOST = 0;
 const COMPILATION_TYPE_EVAL = 1;
 const COMPILATION_TYPE_JSON = 2;
 
 # Matches Messages::kNoLineNumberInfo from v8.h
 const kNoLineNumberInfo = 0;