/*

 * Copyright (c) 2019, Oracle and/or its affiliates. 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 8220416

 * @summary This test uses a class pointer comparison optimization which was not applied anymore since JDK-6964458 resulting in a better IR.

 *

 * @run main/othervm -Xbatch -XX:-TieredCompilation -XX:+IgnoreUnrecognizedVMOptions -XX:+AlwaysIncrementalInline

 *                   -XX:CompileOnly=compiler.c2.CompareKlassPointersTest::test compiler.c2.CompareKlassPointersTest

 */

package compiler.c2;

public class CompareKlassPointersTest {

    static A a;

    public static void main(String[] args) {

        a = new C();

        for (int i = 0; i < 10_000; i++) {

            test();

        }

    }

    public static int test() {

        Object a = getA();

        /*

         * This check is now optimized away which was not the case before anymore since JDK-6964458:

         * The klass pointer comparison optimization sees that the check is always false since a and B are always unrelated klasses

         */

        if (a instanceof B) {

            return 1;

        }

        return 0;

    }

    private static Object getA() {

        return a;

    }

}

class A { }

class B { }

class C extends A { }