CompareKlassPointersTest.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * 2 along with this work; if not, write to the Free Software Foundation,
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/*
 * @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 { }