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/**
 * @test
 * @bug 8199421
 * @summary Test vectorization of popcount
 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UsePopCountInstruction
 *      compiler.vectorization.TestPopCountVector
 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UsePopCountInstruction
 *      -XX:MaxVectorSize=8 compiler.vectorization.TestPopCountVector
 */

package compiler.vectorization;

public class TestPopCountVector {
    private int[] input;
    private int[] output;
    private static final int LEN = 1024;

    public static void main(String args[]) {
        TestPopCountVector test = new TestPopCountVector();
        int err = 0;

        for (int i = 0; i < 10_000; ++i) {
          test.vectorizeBitCount();
        }
        System.out.println("Checking popcount result");
        err += test.checkResult();

        for (int i = 0; i < 10_000; ++i) {
          test.vectorizeBitCount();
        }
        System.out.println("Checking popcount result");
        err += test.checkResult();
        if (err > 0) {
            throw new RuntimeException("Error!");
        }
    }

    public TestPopCountVector() {
        input = new int[LEN];
        output = new int[LEN];
        for (int i = 0; i < LEN; ++i) {
            input[i] = i % 2 == 0 ? i : -1 * i;
        }
    }

    public void vectorizeBitCount() {
        for (int i = 0; i < LEN; ++i) {
            output[i] = Integer.bitCount(input[i]);
        }
    }

    public int checkResult() {
        int err = 0;
        for (int i = 0; i < LEN; ++i) {
            int expected = Integer.bitCount(input[i]);
            if (output[i] != expected) {
                err++;
                System.err.println("Invalid result: output[" + i + "] = " + output[i] + " != " + expected +
                                   ", input[" + i + "] == " + Integer.toBinaryString(input[i]));
            }
        }
        return err;
    }
}