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Fix x64 MathMinMax for negative untagged int32 arguments.

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An untagged int32 has zeros in the upper half even if it is negative.
Using cmpq to compare such numbers will incorrectly ignore the sign.

BUG=164442
R=mvstanton@chromium.org

Review URL: https://chromiumcodereview.appspot.com/11665007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13273 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
ulan@chromium.org 2012-12-21 17:52:00 +00:00
parent d14b05a38d
commit b64f834383
2 changed files with 48 additions and 3 deletions
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6
src/x64/lithium-codegen-x64.cc
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@ -1642,17 +1642,17 @@ void LCodeGen::DoMathMinMax(LMathMinMax* instr) {
if (right->IsConstantOperand()) {
Immediate right_imm =
Immediate(ToInteger32(LConstantOperand::cast(right)));
__ cmpq(left_reg, right_imm);
__ cmpl(left_reg, right_imm);
__ j(condition, &return_left, Label::kNear);
__ movq(left_reg, right_imm);
} else if (right->IsRegister()) {
Register right_reg = ToRegister(right);
__ cmpq(left_reg, right_reg);
__ cmpl(left_reg, right_reg);
__ j(condition, &return_left, Label::kNear);
__ movq(left_reg, right_reg);
} else {
Operand right_op = ToOperand(right);
__ cmpq(left_reg, right_op);
__ cmpl(left_reg, right_op);
__ j(condition, &return_left, Label::kNear);
__ movq(left_reg, right_op);
}

45
test/mjsunit/regress/regress-164442.js Normal file
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@ -0,0 +1,45 @@
// 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:
//
// * 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
// Should not take a very long time (n^2 algorithms are bad)
function ensureNotNegative(x) {
return Math.max(0, x | 0);
}
ensureNotNegative(1);
ensureNotNegative(2);
%OptimizeFunctionOnNextCall(ensureNotNegative);
var r = ensureNotNegative(-1);
assertEquals(0, r);