TestBarrierExpansionDeadMemPhi.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/**
 * @test
 * @bug 8255400
 * @summary C2 failures after JDK-8255000
 * @requires vm.gc.Shenandoah
 * @modules java.base/jdk.internal.misc:+open
 *
 * @run main/othervm -XX:-UseOnStackReplacement -XX:-BackgroundCompilation -XX:-TieredCompilation -XX:+UseShenandoahGC TestBarrierExpansionDeadMemPhi
 *
 *
 */

import jdk.internal.misc.Unsafe;
import java.util.Arrays;
import java.lang.reflect.Field;

public class TestBarrierExpansionDeadMemPhi {

    static final jdk.internal.misc.Unsafe UNSAFE = Unsafe.getUnsafe();

    static final long F_OFFSET;

    static class A {
        int f;
    }

    static {
        try {
            Field fField = A.class.getDeclaredField("f");
            F_OFFSET = UNSAFE.objectFieldOffset(fField);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    static int test(Object[] array) {
        int f = 0;
        for (int i = 0; i < 100; i++) {
            f += UNSAFE.getInt(array[i], F_OFFSET);
        }
        return f;
    }

    static public void main(String[] args) {
        Object[] array = new Object[100];
        Arrays.fill(array, new A());

        for (int i = 0; i < 20000; i++) {
            test(array);
        }
    }
}