test/hotspot/jtreg/compiler/types/TestInterfaceArraySubtypeCheck.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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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,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/*
 * @test
 * @bug 8266615
 * @summary C2 incorrectly folds subtype checks involving an interface array.
 * @run main/othervm -Xbatch
 *                   compiler.types.TestInterfaceArraySubtypeCheck
 */

package compiler.types;

public class TestInterfaceArraySubtypeCheck {

    static interface MyInterface { }

    static class MyClassA { }

    static class MyClassB extends MyClassA implements MyInterface { }

    static MyInterface[] getMyInterfaceArray() {
        return new MyClassB[0];
    }

    static MyInterface getMyInterface() {
        return new MyClassB();
    }

    static MyClassA[] test1() {
        return (MyClassA[])getMyInterfaceArray();
    }

    static void test2() {
        if (!(getMyInterfaceArray() instanceof MyClassA[])) {
            throw new RuntimeException("test2 failed");
        }
    }

    static MyClassA test3() {
        return (MyClassA)getMyInterface();
    }

    static void test4() {
        if (!(getMyInterface() instanceof MyClassA)) {
            throw new RuntimeException("test4 failed");
        }
    }

    public static void main(String[] args) {
        for (int i = 0; i < 50_000; ++i) {
            test1();
            test2();
            test3();
            test4();
        }
    }
}