v8/test/mjsunit/compiler/optimized-instanceof-2.js
bmeurer 551e0aa11b [es6] Reintroduce the instanceof operator in the backends.
This adds back the instanceof operator support in the backends and
introduces a @@hasInstance protector cell on the isolate that guards the
fast path for the InstanceOfStub. This way we recover the ~10%
regression on Octane EarleyBoyer in Crankshaft and greatly improve
TurboFan and Ignition performance of instanceof.

R=ishell@chromium.org
TBR=hpayer@chromium.org,rossberg@chromium.org
BUG=chromium:597249, v8:4447
LOG=n

Review-Url: https://codereview.chromium.org/1980483003
Cr-Commit-Position: refs/heads/master@{#36275}
2016-05-17 11:25:59 +00:00

20 lines
530 B
JavaScript

// 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 --harmony-instanceof
function F() {}
var f = new F
function foo(x) { return x instanceof F };
%OptimizeFunctionOnNextCall(foo);
assertFalse(foo(1));
var proto = Object.getPrototypeOf(F);
Object.setPrototypeOf(F, null);
F[Symbol.hasInstance] = function(v) { return true };
Object.setPrototypeOf(F, proto);
assertTrue(foo(1));