test/hotspot/jtreg/compiler/c2/TestDeadLoopSplitIfLoop.java

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/*
 * @test
 * @key stress randomness
 * @requires vm.compiler2.enabled
 * @bug 8268019
 * @summary Splitting an If through a dying loop header region that is not a LoopNode, yet, results in a dead data loop.
 * @run main/othervm -Xcomp -XX:-TieredCompilation -XX:CompileCommand=compileonly,compiler.c2.TestDeadLoopSplitIfLoop::test -XX:+UnlockDiagnosticVMOptions
 *                   -XX:+StressIGVN -XX:StressSeed=2382674767 -XX:CompileCommand=dontinline,compiler.c2.TestDeadLoopSplitIfLoop::test
 *                   compiler.c2.TestDeadLoopSplitIfLoop
 * @run main/othervm -Xcomp -XX:-TieredCompilation -XX:CompileCommand=compileonly,compiler.c2.TestDeadLoopSplitIfLoop::test -XX:+UnlockDiagnosticVMOptions
 *                   -XX:+StressIGVN -XX:CompileCommand=dontinline,compiler.c2.TestDeadLoopSplitIfLoop::test
 *                   compiler.c2.TestDeadLoopSplitIfLoop
 */
package compiler.c2;

public class TestDeadLoopSplitIfLoop {
    int a;
    int b;
    boolean c;

    public static void main(String[] g) {
        TestDeadLoopSplitIfLoop h = new TestDeadLoopSplitIfLoop();
        h.test();
    }

    void test() {
        int e = 4;
        long f[] = new long[a];
        if (c) {
        } else if (c) {
            // Dead path is removed after parsing which results in a dead data loop for certain node orderings in IGVN.
            switch (126) {
                case 126:
                    do {
                        f[e] = b;
                        switch (6) {
                            case 7:
                                f = f;
                        }
                    } while (e++ < 93);
            }
        }
    }
}