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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 */

/*
 * @test
 * @bug 8344251
 * @summary Test that blackhole without control input are removed
 * @library /test/lib /
 * @run driver compiler.blackhole.DeadBhElimination
 */

package compiler.blackhole;

import compiler.lib.ir_framework.*;

public class DeadBhElimination {
    public static void main(String[] args) {
        TestFramework.runWithFlags(
                "-XX:-TieredCompilation",
                "-XX:+UnlockExperimentalVMOptions",
                // Prevent the dead branches to be compiled into an uncommon trap
                // instead of generating a BlackholeNode.
                "-XX:PerMethodTrapLimit=0",
                "-XX:PerMethodSpecTrapLimit=0",
                "-XX:CompileCommand=blackhole,compiler.blackhole.DeadBhElimination::iAmABlackhole"
        );
    }

    static public void iAmABlackhole(int x) {}

    @Test
    @IR(counts = {IRNode.BLACKHOLE, "1"}, phase = CompilePhase.AFTER_PARSING)
    @IR(failOn = {IRNode.BLACKHOLE}, phase = CompilePhase.FINAL_CODE)
    static void removalAfterLoopOpt() {
        int a = 77;
        int b = 0;
        do {
            a--;
            b++;
        } while (a > 0);
        // b == 77, known after first loop opts round
        // loop is detected as empty loop

        if (b == 78) { // dead
            iAmABlackhole(a);
        }
    }


}