/* * Copyright (c) 2017, Red Hat Inc. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ /** * @test * @bug 8175887 * @summary C1 doesn't respect the JMM with volatile field loads * * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:TieredStopAtLevel=1 VolatileGuardTest */ public class VolatileGuardTest { volatile static private int a; static private int b; static void test() { int tt = b; // makes the JVM CSE the value of b while (a == 0) {} // burn if (b == 0) { System.err.println("wrong value of b"); System.exit(1); // fail hard to report the error } } public static void main(String [] args) throws Exception { for (int i = 0; i < 10; i++) { new Thread(VolatileGuardTest::test).start(); } b = 1; a = 1; } }