instanceof-opt2.js 557 Bytes
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// Copyright 2016 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

function Foo() {}

// TurboFan will optimize this to false via constant-folding the
// OrdinaryHasInstance call inside Function.prototype[@@hasInstance].
function foo() { return 1 instanceof Foo; }

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%PrepareFunctionForOptimization(foo);
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assertEquals(false, foo());
assertEquals(false, foo());
%OptimizeFunctionOnNextCall(foo);
assertEquals(false, foo());