--- /dev/null 2016-10-10 09:13:50.705707062 +0200 +++ new/test/compiler/intrinsics/unsafe/TestCAEAntiDep.java 2016-10-13 12:27:58.022569727 +0200 @@ -0,0 +1,68 @@ +/* + * Copyright (c) 2016, 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 + * or visit www.oracle.com if you need additional information or have any + * questions. + */ + +/** + * @test + * @bug 8167298 + * @summary Unsafe.compareAndExchangeObject should keep track of returned type after matching + * @modules java.base/jdk.internal.misc + * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-BackgroundCompilation -XX:-UseOnStackReplacement -XX:-UseCompressedOops TestCAEAntiDep + * + */ + +import java.lang.reflect.Field; +import jdk.internal.misc.Unsafe; + +public class TestCAEAntiDep { + static final jdk.internal.misc.Unsafe UNSAFE = Unsafe.getUnsafe(); + static final long O_OFFSET; + + static class C { + int f1; + } + + C o = new C(); + + static { + try { + Field oField = TestCAEAntiDep.class.getDeclaredField("o"); + O_OFFSET = UNSAFE.objectFieldOffset(oField); + } catch (Exception e) { + throw new RuntimeException(e); + } + } + + static int m(TestCAEAntiDep test, Object expected, Object x) { + C old = (C)UNSAFE.compareAndExchangeObjectVolatile(test, O_OFFSET, expected, x); + int res = old.f1; + old.f1 = 0x42; + return res; + } + + static public void main(String[] args) { + TestCAEAntiDep test = new TestCAEAntiDep(); + for (int i = 0; i < 20000; i++) { + m(test, test.o, test.o); + } + } +}