test/hotspot/jtreg/compiler/codegen/ShiftByZero.java

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 */

/*
 * @test
 * @bug 8288445
 * @summary Test shift by 0
 * @run main/othervm -Xbatch -XX:-TieredCompilation
 * compiler.codegen.ShiftByZero
 */

package compiler.codegen;

public class ShiftByZero {

    public static final int N = 64;

    public static int[] i32 = new int[N];

    public static void bMeth() {
        int shift = i32[0];
        // This loop is to confuse the optimizer, so that "shift" is
        // optimized to 0 only after loop vectorization.
        for (int i8 = 279; i8 > 1; --i8) {
            shift <<= 6;
        }
        // low 6 bits of shift are 0, so shift can be
        // simplified to constant 0
        {
            for (int i = 0; i < N; ++i) {
                i32[i] += i32[i] >>= shift;
            }
            for (int i = 0; i < N; ++i) {
                i32[i] += i32[i] >>>= shift;
            }
            for (int i = 0; i < N; ++i) {
                i32[i] >>>= shift;
            }
            for (int i = 0; i < N; ++i) {
                i32[i] >>= shift;
            }
            for (int i = 0; i < N; ++i) {
                i32[i] <<= shift;
            }
        }
    }

    public static void main(String[] strArr) {
        for (int i = 0; i < 20_000; i++) {
            bMeth();
        }
    }
}