/*

 * 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

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 */

import java.lang.reflect.Field;

/**

 * @test

 * @bug 8175887

 * @summary C1 value numbering handling of Unsafe.get*Volatile is incorrect

 * @modules java.base/jdk.internal.misc

 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:TieredStopAtLevel=1 UnsafeVolatileGuardTest

 */

public class UnsafeVolatileGuardTest {

    volatile static private int a;

    static private int b;

    static final jdk.internal.misc.Unsafe UNSAFE = jdk.internal.misc.Unsafe.getUnsafe();

    static final Object BASE;

    static final long OFFSET;

    static {

        try {

            Field f = UnsafeVolatileGuardTest.class.getDeclaredField("a");

            BASE = UNSAFE.staticFieldBase(f);

            OFFSET = UNSAFE.staticFieldOffset(f);

        } catch (Exception e) {

            throw new RuntimeException(e);

        }

    }

    static void test() {

        int tt = b; // makes the JVM CSE the value of b

        while (UNSAFE.getIntVolatile(BASE, OFFSET) == 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(UnsafeVolatileGuardTest::test).start();

        }

        b = 1;

        a = 1;

    }

}