56f6a763c2
Previously we'd check `x` for -0 by testing `(1.0 / x) == -Infinity`, but this will yield the wrong results when `x` is a subnormal, i.e. really close to 0. In CSA we already perform bit checks to test for -0, so teach TurboFan to do the same for comparisons to -0 (via `Object.is`). We introduce a new NumberIsMinusZero simplified operator to handle the case where SimplifiedLowering already knows that the input is a number. Bug: chromium:903043, v8:6882 Change-Id: I0cb7c568029b461a92fc183104d5f359b4bfe7f4 Reviewed-on: https://chromium-review.googlesource.com/c/1328802 Commit-Queue: Benedikt Meurer <bmeurer@chromium.org> Reviewed-by: Sigurd Schneider <sigurds@chromium.org> Cr-Commit-Position: refs/heads/master@{#57382}
40 lines
835 B
JavaScript
40 lines
835 B
JavaScript
// Copyright 2018 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// Flags: --allow-natives-syntax
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(function() {
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function foo() {
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const x = 1e-1;
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return Object.is(-0, x * (-1e-308));
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}
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assertFalse(foo());
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assertFalse(foo());
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%OptimizeFunctionOnNextCall(foo);
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assertFalse(foo());
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})();
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(function() {
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function foo(x) {
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return Object.is(-0, x * (-1e-308));
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}
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assertFalse(foo(1e-1));
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assertFalse(foo(1e-1));
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%OptimizeFunctionOnNextCall(foo);
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assertFalse(foo(1e-1));
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})();
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(function() {
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function foo(x) {
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return Object.is(-0, x);
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}
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assertFalse(foo(1e-1 * (-1e-308)));
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assertFalse(foo(1e-1 * (-1e-308)));
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%OptimizeFunctionOnNextCall(foo);
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assertFalse(foo(1e-1 * (-1e-308)));
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})();
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