test/hotspot/jtreg/compiler/stable/TestStableMemoryBarrier.java

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/*
 * @test TestStableMemoryBarrier
 * @bug 8139758
 * @summary tests memory barrier correctly inserted for stable fields
 * @modules java.base/jdk.internal.vm.annotation
 *
 * @run main/bootclasspath/othervm -Xcomp -XX:CompileOnly=::testCompile
 *                                 compiler.stable.TestStableMemoryBarrier
 *
 * @author hui.shi@linaro.org
 */

package compiler.stable;

import jdk.internal.vm.annotation.Stable;

public class TestStableMemoryBarrier {
    public static void main(String[] args) throws Exception {
        for (int i = 0; i < 1000000; i++) {
            NotDominate.testCompile(i);
        }
    }
    /* ====================================================
     * Stable field initialized in method, but its allocation
     * doesn't dominate MemBar Release at the end of method.
     */
    private static class NotDominate {
        public @Stable int v;
        public static int[] array = new int[100];

        public static NotDominate testCompile(int n) {
            if ((n % 2) == 0) return null;
            // add a loop here, trigger PhaseIdealLoop::verify_dominance
            for (int i = 0; i < 100; i++) {
                array[i] = n;
            }
            NotDominate nm = new NotDominate();
            nm.v = n;
            return nm;
        }


    }
}