v8/test/mjsunit/constant-fold-control-instructions.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

36 lines
920 B
JavaScript

// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --allow-natives-syntax --fold-constants
function test() {
assertEquals("string", typeof "");
assertEquals("number", typeof 1.1);
assertEquals("number", typeof 1);
assertEquals("boolean", typeof true);
assertEquals("function", typeof function() {});
assertEquals("object", typeof null);
assertEquals("object", typeof {});
assertEquals("object", typeof /regex/);
assertTrue(%_IsSmi(1));
assertFalse(%_IsSmi(1.1));
assertFalse(%_IsSmi({}));
assertTrue(%_IsRegExp(/regexp/));
assertFalse(%_IsRegExp({}));
assertTrue(%_IsArray([1]));
assertFalse(%_IsArray(function() {}));
assertTrue(%_IsJSReceiver(new Date()));
assertFalse(%_IsJSReceiver(1));
}
test();
test();
%OptimizeFunctionOnNextCall(test);
test();