Avoid FP exceptions when doing integer division.

BUG=v8:3039
R=titzer@chromium.org

Review URL: https://codereview.chromium.org/104003004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18277 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 4f918b3..e7ad219 100644 (file)
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -1776,10 +1776,7 @@ Range* HDiv::InferRange(Zone* zone) {
     result->set_can_be_minus_zero(!CheckFlag(kAllUsesTruncatingToInt32) &&
                                   (a->CanBeMinusZero() ||
                                    (a->CanBeZero() && b->CanBeNegative())));
-    if (!a->Includes(kMinInt) ||
-        !b->Includes(-1) ||
-        CheckFlag(kAllUsesTruncatingToInt32)) {
-      // It is safe to clear kCanOverflow when kAllUsesTruncatingToInt32.
+    if (!a->Includes(kMinInt) || !b->Includes(-1)) {
       ClearFlag(HValue::kCanOverflow);
     }
 

diff --git a/test/mjsunit/div-mul-minus-one.js b/test/mjsunit/div-mul-minus-one.js
index f05bf0f..5ade614 100644 (file)
--- a/test/mjsunit/div-mul-minus-one.js
+++ b/test/mjsunit/div-mul-minus-one.js
@@ -36,9 +36,7 @@ var expected_MinInt = div(kMinInt);
 var expected_minus_zero = div(0);
 %OptimizeFunctionOnNextCall(div);
 assertEquals(expected_MinInt, div(kMinInt));
-assertOptimized(div);
 assertEquals(expected_minus_zero , div(0));
-assertOptimized(div);
 
 function mul(g) {
   return (g * -1) ^ 1

diff --git a/test/mjsunit/regress/regress-3039.js b/test/mjsunit/regress/regress-3039.js
new file mode 100644 (file)
index 0000000..3c7f62c
--- /dev/null
+++ b/test/mjsunit/regress/regress-3039.js
@@ -0,0 +1,41 @@
+// 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 do_div(x, y) {
+  return (x / y) | 0;
+}
+
+// Preparation.
+assertEquals(17, do_div(51, 3));
+assertEquals(13, do_div(65, 5));
+%OptimizeFunctionOnNextCall(do_div);
+assertEquals(11, do_div(77, 7));
+
+// The actual test. We should not trigger a floating point exception.
+assertEquals(-2147483648, do_div(-2147483648, -1));