v8/test/mjsunit/regress/regress-crbug-891627.js

// 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

// We need a NumberModulus, so we make sure that we have a
// SpeculativeNumberModulus with Number feedback, and later
// on use it with known Number inputs (via the bitwise or),
// such that JSTypedLowering turns it into the NumberModulus.
function bar(x) { return x % 2; }
bar(0.1);

// Check that the Word32->Float64 conversion works properly.
(function() {
  function foo(x) {
    // The NumberEqual identifies 0 and -0.
    return bar(x | -1) == 4294967295;
  }

  %PrepareFunctionForOptimization(foo);
  assertFalse(foo(1));
  assertFalse(foo(0));
  %OptimizeFunctionOnNextCall(foo);
  assertFalse(foo(1));
  assertFalse(foo(0));
})();

// Check that the Word32->Word32 conversion works properly.
(function() {
  function makeFoo(y) {
    return function foo(x) {
      return bar(x | -1) == y;
    }
  }
  makeFoo(0);  // Defeat the function context specialization.
  const foo = makeFoo(1);

  %PrepareFunctionForOptimization(foo);
  assertFalse(foo(1));
  assertFalse(foo(0));
  %OptimizeFunctionOnNextCall(foo);
  assertFalse(foo(1));
  assertFalse(foo(0));
})();