|  | // Copyright 2014 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 p(x) { | 
|  | this.x = x; | 
|  | } | 
|  |  | 
|  | function f() { | 
|  | var a = new p(1), b = new p(2); | 
|  | for (var i = 0; i < 1; i++) { | 
|  | a.x += b.x; | 
|  | } | 
|  | return a.x; | 
|  | }; | 
|  | %PrepareFunctionForOptimization(f); | 
|  | new p(0.1);  // make 'x' mutable box double field in p. | 
|  |  | 
|  | assertEquals(3, f()); | 
|  | assertEquals(3, f()); | 
|  | %OptimizeFunctionOnNextCall(f); | 
|  | assertEquals(3, f()); |