--- /dev/null 2014-08-18 06:44:45.001973014 +0200 +++ new/test/compiler/membars/TestMemBarAcquire.java 2014-08-18 11:12:11.437309383 +0200 @@ -0,0 +1,52 @@ +/* + * Copyright (c) 2014, 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 TestMemBarAcquire + * @bug 8048879 + * @summary "Tests optimization of MemBarAcquireNodes" + * @run main/othervm -XX:-TieredCompilation -XX:-BackgroundCompilation TestMemBarAcquire + */ +public class TestMemBarAcquire { + private volatile static Object defaultObj = new Object(); + private Object obj; + + public TestMemBarAcquire(Object param) { + // Volatile load. MemBarAcquireNode is added after the + // load to prevent following loads from floating up past. + // StoreNode is added to store result of load in 'obj'. + this.obj = defaultObj; + // Overrides 'obj' and therefore makes previous StoreNode + // and the corresponding LoadNode useless. However, the + // LoadNode is still connected to the MemBarAcquireNode + // that should now release the reference. + this.obj = param; + } + + public static void main(String[] args) throws Exception { + // Make sure TestMemBarAcquire:: is compiled + for (int i = 0; i < 100000; ++i) { + TestMemBarAcquire p = new TestMemBarAcquire(new Object()); + } + } +}