From eb04a6a95fc32805d5051459b927b98f3818dd97 Mon Sep 17 00:00:00 2001
From: "serya@chromium.org"
 <serya@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Tue, 6 Apr 2010 10:40:25 +0000
Subject: [PATCH] JS implementation of isFinite. Review URL:
 http://codereview.chromium.org/1608003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4344 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/runtime.cc   | 15 ---------------
 src/runtime.h    |  1 -
 src/v8natives.js |  5 ++++-
 3 files changed, 4 insertions(+), 17 deletions(-)

diff --git a/src/runtime.cc b/src/runtime.cc
index 4b35924c47..40b37d96e1 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -7100,21 +7100,6 @@ static Object* Runtime_DateDaylightSavingsOffset(Arguments args) {
 }
 
 
-static Object* Runtime_NumberIsFinite(Arguments args) {
-  NoHandleAllocation ha;
-  ASSERT(args.length() == 1);
-
-  CONVERT_DOUBLE_CHECKED(value, args[0]);
-  Object* result;
-  if (isnan(value) || (fpclassify(value) == FP_INFINITE)) {
-    result = Heap::false_value();
-  } else {
-    result = Heap::true_value();
-  }
-  return result;
-}
-
-
 static Object* Runtime_GlobalReceiver(Arguments args) {
   ASSERT(args.length() == 1);
   Object* global = args[0];
diff --git a/src/runtime.h b/src/runtime.h
index a55a27135b..c079345ef9 100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -210,7 +210,6 @@ namespace internal {
   F(DateYMDFromTime, 2, 1) \
   \
   /* Numbers */ \
-  F(NumberIsFinite, 1, 1) \
   \
   /* Globals */ \
   F(CompileString, 2, 1) \
diff --git a/src/v8natives.js b/src/v8natives.js
index fc787367ee..86d3ad87c9 100644
--- a/src/v8natives.js
+++ b/src/v8natives.js
@@ -82,7 +82,10 @@ function GlobalIsNaN(number) {
 
 // ECMA 262 - 15.1.5
 function GlobalIsFinite(number) {
-  return %NumberIsFinite(ToNumber(number));
+  if (!IS_NUMBER(number)) number = ToNumber(number);
+
+  // NaN - NaN == NaN, Infinity - Infinity == NaN, -Infinity - -Infinity == NaN.
+  return %_IsSmi(number) || number - number == 0;
 }