v8/test/mjsunit/compiler/minus-zero.js
bmeurer 00f7d1f5f8 [intrinsics] Kill the %_IsMinusZero intrinsic.
By now only the default %TypedArray%.prototype.sort compare function
and the JS implementation of SameValueZero were still using the odd
%_IsMinusZero intrinsic, whose semantics both included a number check
(actually HeapNumber test) plus testing if the heap number stores the
special -0 value. In both cases we already know that we deal with
number so we can reduce it to a simple number test for -0, which can
be expressed via dividing 1 by that value and checking the sign of
the result. In case of the compare function, we can be even smarter
and work with the reciprocal values in case x and y are equal to 0
(although long term we should probably rewrite the fast case for
the typed array sorting function in C++ anyway, which will be way,
way faster than our handwritten callback-style, type-feedback
polluted JS implementation).

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/1680783002

Cr-Commit-Position: refs/heads/master@{#33833}
2016-02-09 06:28:53 +00:00

70 lines
2.3 KiB
JavaScript

// 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 --no-fold-constants
function add(x, y) {
return x + y;
}
assertEquals(0, add(0, 0));
assertEquals(0, add(0, 0));
%OptimizeFunctionOnNextCall(add);
assertEquals(-0, add(-0, -0));
function testsin() {
assertEquals(-0, Math.sin(-0));
}
testsin();
testsin();
%OptimizeFunctionOnNextCall(testsin);
testsin();
function testfloor() {
assertEquals(-0, Math.floor(-0));
}
testfloor();
testfloor();
%OptimizeFunctionOnNextCall(testfloor);
testfloor();
var double_one = Math.cos(0);
function add(a, b) {
return a + b;
}
assertEquals(1, 1/add(double_one, 0));
assertEquals(1, 1/add(0, double_one));
%OptimizeFunctionOnNextCall(add);
assertEquals(1/(-0 + -0), 1/add(-0, -0));