v8/test/mjsunit/compiler/deopt-lazy-freeze.js

// Copyright 2017 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

var b = false;
var obj = {f: 1, g: 2};

function setMutability() {
  if (b) Object.freeze(obj);
}
%NeverOptimizeFunction(setMutability);

function setAndUseObject() {
  setMutability(obj);
  if (!Object.isFrozen(obj)) {
    var t = obj.f;
    obj.f = t * 2;
  }
  return obj.f;
}

%PrepareFunctionForOptimization(setAndUseObject);
assertEquals(setAndUseObject(), 2);
assertEquals(setAndUseObject(), 4);
%OptimizeFunctionOnNextCall(setAndUseObject);
b = true;
assertEquals(setAndUseObject(), 4);