Experimental profiler: split RegExp.test() for better optimization.

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/9701064

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11065 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/regexp.js

@@ -250,29 +250,32 @@ function RegExpTest(string) {
     // Remove irrelevant preceeding '.*' in a non-global test regexp.
     // The expression checks whether this.source starts with '.*' and
     // that the third char is not a '?'.
-    if (%_StringCharCodeAt(this.source, 0) == 46 &&  // '.'
-        %_StringCharCodeAt(this.source, 1) == 42 &&  // '*'
-        %_StringCharCodeAt(this.source, 2) != 63) {  // '?'
-      if (!%_ObjectEquals(regexp_key, this)) {
-        regexp_key = this;
-        regexp_val = new $RegExp(SubString(this.source, 2, this.source.length),
-                                 (!this.ignoreCase
-                                  ? !this.multiline ? "" : "m"
-                                  : !this.multiline ? "i" : "im"));
-      }
-      if (%_RegExpExec(regexp_val, string, 0, lastMatchInfo) === null) {
-        return false;
-      }
+    var regexp = this;
+    if (%_StringCharCodeAt(regexp.source, 0) == 46 &&  // '.'
+        %_StringCharCodeAt(regexp.source, 1) == 42 &&  // '*'
+        %_StringCharCodeAt(regexp.source, 2) != 63) {  // '?'
+      regexp = TrimRegExp(regexp);
     }
-    %_Log('regexp', 'regexp-exec,%0r,%1S,%2i', [this, string, lastIndex]);
+    %_Log('regexp', 'regexp-exec,%0r,%1S,%2i', [regexp, string, lastIndex]);
     // matchIndices is either null or the lastMatchInfo array.
-    var matchIndices = %_RegExpExec(this, string, 0, lastMatchInfo);
+    var matchIndices = %_RegExpExec(regexp, string, 0, lastMatchInfo);
     if (matchIndices === null) return false;
     lastMatchInfoOverride = null;
     return true;
   }
 }
 
+function TrimRegExp(regexp) {
+  if (!%_ObjectEquals(regexp_key, regexp)) {
+    regexp_key = regexp;
+    regexp_val =
+      new $RegExp(SubString(regexp.source, 2, regexp.source.length),
+                  (regexp.ignoreCase ? regexp.multiline ? "im" : "i"
+                                     : regexp.multiline ? "m" : ""));
+  }
+  return regexp_val;
+}
+
 
 function RegExpToString() {
   // If this.source is an empty string, output /(?:)/.

test/mjsunit/regexp.js

-// Copyright 2008 the V8 project authors. All rights reserved.
+// Copyright 2012 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:
@@ -701,3 +701,7 @@ assertThrows("RegExp('(*)')");
 assertThrows("RegExp('(?:*)')");
 assertThrows("RegExp('(?=*)')");
 assertThrows("RegExp('(?!*)')");
+
+// Test trimmed regular expression for RegExp.test().
+assertTrue(/.*abc/.test("abc"));
+assertFalse(/.*\d+/.test("q"));