Optimize isFinite and isNaN.

src/string.js

Index: src/string.js
diff --git a/src/string.js b/src/string.js
index 6f68ce089096db33a4e5c3f52a9a4ead7595400c..a70eeade83b9d68b51937611b621b628fa6be286 100644
--- a/src/string.js
+++ b/src/string.js
@@ -911,47 +911,50 @@ function ReplaceResultBuilder(str) {
   this.special_string = str;
 }
 
-SetUpLockedPrototype(ReplaceResultBuilder,
-  $Array("elements", "special_string"), $Array(
-  "add", function(str) {
-    str = TO_STRING_INLINE(str);
-    if (str.length > 0) this.elements.push(str);
-  },
-  "addSpecialSlice", function(start, end) {
-    var len = end - start;
-    if (start < 0 || len <= 0) return;
-    if (start < 0x80000 && len < 0x800) {
-      this.elements.push((start << 11) | len);
-    } else {
-      // 0 < len <= String::kMaxLength and Smi::kMaxValue >= String::kMaxLength,
-      // so -len is a smi.
-      var elements = this.elements;
-      elements.push(-len);
-      elements.push(start);
-    }
-  },
-  "generate", function() {
+ReplaceResultBuilder.prototype.__proto__ = null;
+
+
+ReplaceResultBuilder.prototype.add = function(str) {
+  str = TO_STRING_INLINE(str);
+  if (str.length > 0) this.elements.push(str);
+}
+
+
+ReplaceResultBuilder.prototype.addSpecialSlice = function(start, end) {
+  var len = end - start;
+  if (start < 0 || len <= 0) return;
+  if (start < 0x80000 && len < 0x800) {
+    this.elements.push((start << 11) | len);
+  } else {
+    // 0 < len <= String::kMaxLength and Smi::kMaxValue >= String::kMaxLength,
+    // so -len is a smi.
     var elements = this.elements;
-    return %StringBuilderConcat(elements, elements.length, this.special_string);
+    elements.push(-len);
+    elements.push(start);
   }
-));
+}
+
+
+ReplaceResultBuilder.prototype.generate = function() {
+  var elements = this.elements;
+  return %StringBuilderConcat(elements, elements.length, this.special_string);
+}
 
 
 // -------------------------------------------------------------------
 
-function SetUpString() {
-  %CheckIsBootstrapping();
-  // Set up the constructor property on the String prototype object.
+function SetupString() {
+  // Setup the constructor property on the String prototype object.
   %SetProperty($String.prototype, "constructor", $String, DONT_ENUM);
 
 
-  // Set up the non-enumerable functions on the String object.
+  // Setup the non-enumerable functions on the String object.
   InstallFunctions($String, DONT_ENUM, $Array(
     "fromCharCode", StringFromCharCode
   ));
 
 
-  // Set up the non-enumerable functions on the String prototype object.
+  // Setup the non-enumerable functions on the String prototype object.
   InstallFunctionsOnHiddenPrototype($String.prototype, DONT_ENUM, $Array(
     "valueOf", StringValueOf,
     "toString", StringToString,
@@ -991,4 +994,5 @@ function SetUpString() {
   ));
 }
 
-SetUpString();
+
+SetupString();