test/hotspot/jtreg/compiler/profiling/TestMultiBranchDataOverflow.java

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/**
 * @test
 * @bug 8251458
 * @summary Test int range overflow of MultiBranchData counter.
 * @run main/othervm -XX:CompileCommand=dontinline,compiler.profiling.TestMultiBranchDataOverflow::test
 *                   -Xbatch -XX:Tier4BackEdgeThreshold=2147483647
 *                   compiler.profiling.TestMultiBranchDataOverflow
 */

package compiler.profiling;

public class TestMultiBranchDataOverflow {

    public static int test(int val, long max) {
        int res = 0;
        for (long l = 0; l < max; ++l) {
            switch (val) {
            case 0:
                return 0;
            case 42:
                res++;
                break;
            }
        }
        return res;
    }

    public static void main(String[] args) {
        // Warmup to generate profile information that has a MultiBranchData
        // counter > Integer.MAX_VALUE for the i == 42 lookupswitch branch.
        long max = Integer.MAX_VALUE + 100_000L;
        test(42, max);

        // Trigger C2 compilation
        for (int i = 0; i < 10_000; ++i) {
            test(42, 1);
        }
    }
}