PeelingAndLoopStripMining.java

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/*
 * @test
 * @bug 8229994
 * @summary Tests dominance in PhaseIdealLoop::get_early_ctrl_for_expensive() if an expensive SqrtD node is peeled.
 *
 * @run main/othervm -Xbatch -XX:-TieredCompilation
 *                   -XX:CompileCommand=compileonly,compiler.loopopts.PeelingAndLoopStripMining::*
 *                   compiler.loopopts.PeelingAndLoopStripMining
 */

package compiler.loopopts;

public class PeelingAndLoopStripMining {

    static double dFld = 3.3;

    public void test(int k) {
        for (int i = 1; i < 100; i++) {
            // Loop invariant check triggers loop peeling
            if (k == 300) {
                return;
            }

            /*
             * sqrtAdd() is inlined which contains an expensive node SqrtD with a control input from the above IfTrue node 'ifT'
             * (flipped in IR, i.e. when not returning). PhaseIdealLoop::peeled_dom_test_elim() will change the control input
             * of SqrtD to the peeled IfTrue node 'pifT' of 'ifT' and test if 'pifT' is on the idom chain starting from 'ifT'.
             * This failed previously because the new loop entry from the peeled iteration was always set as idom of the
             * CountedLoop node and not of the OuterStripMinedLoop node if present. Thus, 'pifT' was not found on the idom chain
             * starting from 'ifT' resulting in a bad graph assertion failure in PhaseIdealLoop::get_early_ctrl_for_expensive().
             */
            dFld = sqrtAdd(i);
        }
    }

    public static void main(String[] strArr) {
        PeelingAndLoopStripMining _instance = new SubClass();
        for (int i = 0; i < 10000; i++ ) {
            _instance.test(12);
        }

        _instance = new PeelingAndLoopStripMining();
        for (int i = 0; i < 10000; i++ ) {
            _instance.test(300);
        }
        for (int i = 0; i < 10000; i++ ) {
            _instance.test(45);
        }
    }

    public double sqrtAdd(int i) {
        return 1.0 + Math.sqrt(i);
    }
}

class SubClass extends PeelingAndLoopStripMining {
    public double sqrtAdd(int i) {
        return 2.0 + Math.sqrt(i);
    }
}