Fix overflow check computation for Smi Phis

BUG=v8:2836
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/22629011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16180 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen-representation-changes.cc

@@ -127,7 +127,7 @@ void HRepresentationChangesPhase::Run() {
            !(input_representation.IsInteger32() &&
              use->CheckFlag(HValue::kTruncatingToInt32))) ||
           (phi->representation().IsSmi() &&
-           !(input_representation.IsSmi() ||
+           !(input_representation.IsSmi() &&
              use->CheckFlag(HValue::kTruncatingToSmi)))) {
         if (FLAG_trace_representation) {
           PrintF("#%d Phi is not truncating because of #%d %s\n",

test/mjsunit/regress/regress-2836.js

+// Copyright 2013 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.
+
+// Flags: --allow-natives-syntax
+
+function f() {
+  var end = 1073741823;  // 2^30 - 1
+  var start = end - 100000;  // Run long enough to trigger OSR.
+  for (var i = start; i <= end; ++i) {
+    assertTrue(i >= start);  // No overflow allowed!
+  }
+}
+
+f();