Reviewers: William Hesse,
Description:
Optimize isFinite and isNaN.
Arithmetic on infinities and NaN is much slower than doing several exact
comparisons.
Please review this at http://codereview.chromium.org/7830036/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/v8natives.js
Index: src/v8natives.js
diff --git a/src/v8natives.js b/src/v8natives.js
index
2039fea2766316f7bfa9f4038b115df734d11ac4..6e8d5bbad33ccf1c92ffa0bb6bc83ab456534a4a
100644
--- a/src/v8natives.js
+++ b/src/v8natives.js
@@ -41,7 +41,6 @@
const $isNaN = GlobalIsNaN;
const $isFinite = GlobalIsFinite;
-
//
----------------------------------------------------------------------------
@@ -86,17 +85,15 @@ function InstallFunctionsOnHiddenPrototype(object,
attributes, functions) {
// ECMA 262 - 15.1.4
function GlobalIsNaN(number) {
- var n = ToNumber(number);
- return NUMBER_IS_NAN(n);
+ if (!IS_NUMBER(number)) number = NonNumberToNumber(number);
+ return NUMBER_IS_NAN(number);
}
// ECMA 262 - 15.1.5
function GlobalIsFinite(number) {
if (!IS_NUMBER(number)) number = NonNumberToNumber(number);
-
- // NaN - NaN == NaN, Infinity - Infinity == NaN, -Infinity - -Infinity
== NaN.
- return %_IsSmi(number) || number - number == 0;
+ return !NUMBER_IS_NAN(number) && number !== (1 / 0) && number !== (-1 /
0);
}
--
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