8154537: AArch64: some integer rotate instructions are never emitted
Reviewed-by: aph, adinn, kvn
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/*
* @test
* @bug 8080190
* @bug 8154537
* @key regression
* @summary Test that the rotate distance used in the rotate instruction is properly masked with 0x1f
* @run main/othervm -Xbatch -XX:-UseOnStackReplacement IntRotateWithImmediate
* @author volker.simonis@gmail.com
*/
public class IntRotateWithImmediate {
// This is currently the same as Integer.rotateRight()
static int rotateRight1(int i, int distance) {
// On some architectures (i.e. x86_64 and ppc64) the following computation is
// matched in the .ad file into a single MachNode which emmits a single rotate
// machine instruction. It is important that the shift amount is masked to match
// corresponding immediate width in the native instruction. On x86_64 the rotate
// left instruction ('rol') encodes an 8-bit immediate while the corresponding
// 'rotlwi' instruction on Power only encodes a 5-bit immediate.
return ((i >>> distance) | (i << -distance));
}
static int rotateRight2(int i, int distance) {
return ((i >>> distance) | (i << (32-distance)));
}
static int compute1(int x) {
return rotateRight1(x, 3);
}
static int compute2(int x) {
return rotateRight2(x, 3);
}
public static void main(String args[]) {
int val = 4096;
int firstResult = compute1(val);
for (int i = 0; i < 100000; i++) {
int newResult = compute1(val);
if (firstResult != newResult) {
throw new InternalError(firstResult + " != " + newResult);
}
newResult = compute2(val);
if (firstResult != newResult) {
throw new InternalError(firstResult + " != " + newResult);
}
}
System.out.println("OK");
}
}