v8/test/mjsunit/compiler/number-subtract.js
Benedikt Meurer 2c40c5250b [turbofan] Test coverage for SpeculativeNumberAdd/Subtract in SimplifiedLowering.
This adds missing test coverage for corner cases of SpeculativeNumberAdd
and SpeculativeNumberSubtract inside of SimplifiedLowering. This was
discovered to be untested by the coverage bot.

Bug: v8:8015
Change-Id: I7355b1b840a76bc12bd911adb6c2d88f05d816c5
Reviewed-on: https://chromium-review.googlesource.com/1236256
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56090}
2018-09-20 14:23:34 +00:00

35 lines
1.1 KiB
JavaScript

// Copyright 2018 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
// This tests that SpeculativeNumberSubtract can still lower to
// Int32Sub in SimplifiedLowering, which requires some magic
// to make sure that SpeculativeNumberSubtract survives to that
// point, especially the JSTypedLowering needs to be unable
// to tell that the inputs to SpeculativeNumberAdd are not
// Number, Undefined, Null or Boolean.
(function() {
// We need a function that has a - with feedback Number or
// NumberOrOddball, but for whose inputs the JSTypedLowering
// cannot reduce it to NumberSubtract (with SpeculativeToNumber
// conversions). We achieve this utilizing an object literal
// indirection here.
function baz(x) {
return {x}.x - x;
}
baz(null);
baz(undefined);
// Now we just need to truncate the result.
function foo(x) {
return baz(42) | 0;
}
assertEquals(0, foo());
assertEquals(0, foo());
%OptimizeFunctionOnNextCall(foo);
assertEquals(0, foo());
})();