Fix regexp bug reported by Ian where [6-9] would match any digit.

Review URL: http://codereview.chromium.org/140021

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2226 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/jsregexp.cc

@@ -1885,7 +1885,8 @@ void TextNode::GetQuickCheckDetails(QuickCheckDetails* details,
         uint32_t differing_bits = (from ^ to);
         // A mask and compare is only perfect if the differing bits form a
         // number like 00011111 with one single block of trailing 1s.
-        if ((differing_bits & (differing_bits + 1)) == 0) {
+        if ((differing_bits & (differing_bits + 1)) == 0 &&
+             from + differing_bits == to) {
           pos->determines_perfectly = true;
         }
         uint32_t common_bits = ~SmearBitsRight(differing_bits);

test/mjsunit/regress/regress-6-9-regexp.js

+// Copyright 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Check that the perfect mask check isn't overly optimistic.
+
+assertFalse(/[6-9]/.test('2'));