1 /*
2  * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
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8  *
9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
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17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
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22  */
23 
24 /*
25  * @test
26  * @bug 8220416
27  * @summary This test uses a class pointer comparison optimization which was not applied anymore since JDK-6964458 resulting in a better IR.
28  *
29  * @run main/othervm -Xbatch -XX:-TieredCompilation -XX:+IgnoreUnrecognizedVMOptions -XX:+AlwaysIncrementalInline
30  *                   -XX:CompileOnly=compiler.c2.CompareKlassPointersTest::test compiler.c2.CompareKlassPointersTest
31  */
32 
33 package compiler.c2;
34 
35 
36 
37 public class CompareKlassPointersTest {
38 
39     static A a;
40 
main(String[] args)41     public static void main(String[] args) {
42         a = new C();
43         for (int i = 0; i < 10_000; i++) {
44             test();
45         }
46     }
47 
test()48     public static int test() {
49         Object a = getA();
50 
51         /*
52          * This check is now optimized away which was not the case before anymore since JDK-6964458:
53          * The klass pointer comparison optimization sees that the check is always false since a and B are always unrelated klasses
54          */
55         if (a instanceof B) {
56             return 1;
57         }
58         return 0;
59     }
60 
getA()61     private static Object getA() {
62         return a;
63     }
64 }
65 
66 class A { }
67 
68 class B { }
69 
70 class C extends A { }
71