05459df0c7
Use the compilation-local seed in 'StressLCM' and 'StressGCM' rather than the global one. As a consequence, these options use by default a fresh seed in every compilation, unless 'StressSeed=N' is specified, in which case they behave deterministically. Annotate tests that use 'StressLCM' and 'StressGCM' with the 'stress' and 'randomness' keys to reflect this change in default behavior. Reviewed-by: kvn, thartmann
86 lines
3.1 KiB
Java
86 lines
3.1 KiB
Java
/*
|
|
* Copyright (c) 2020, Red Hat, Inc. All rights reserved.
|
|
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
|
|
*
|
|
* This code is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 only, as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This code is distributed in the hope that it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* version 2 for more details (a copy is included in the LICENSE file that
|
|
* accompanied this code).
|
|
*
|
|
* You should have received a copy of the GNU General Public License version
|
|
* 2 along with this work; if not, write to the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*
|
|
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
|
|
* or visit www.oracle.com if you need additional information or have any
|
|
* questions.
|
|
*/
|
|
|
|
/*
|
|
* @test
|
|
* @key stress randomness
|
|
* @bug 8241900
|
|
* @summary Loop unswitching may cause dependence on null check to be lost
|
|
*
|
|
* @requires vm.compiler2.enabled
|
|
* @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:-TieredCompilation -XX:-BackgroundCompilation -XX:+StressGCM -XX:+StressLCM TestLoopUnswitchingLostCastDependency
|
|
*/
|
|
|
|
import java.util.Arrays;
|
|
|
|
public class TestLoopUnswitchingLostCastDependency {
|
|
private static Object objectField;
|
|
|
|
public static void main(String[] args) {
|
|
Object[] array = new Object[100];
|
|
Arrays.fill(array, new Object());
|
|
for (int i = 0; i < 20_000; i++) {
|
|
array[1] = null;
|
|
test(array);
|
|
array[1] = new Object();
|
|
objectField = null;
|
|
test(array);
|
|
array[1] = new Object();
|
|
objectField = new Object();
|
|
test(array);
|
|
}
|
|
}
|
|
|
|
private static void test(Object[] array) {
|
|
Object o = objectField;
|
|
Object o3 = array[1];
|
|
int j = 0;
|
|
for (int i = 1; i < 100; i *= 2) {
|
|
Object o2 = array[i];
|
|
// Both branches taken: loop is unswitched.
|
|
if (o3 != null) {
|
|
if (o2 == null) {
|
|
}
|
|
// Both branches taken: loop is unswitched next.
|
|
if (o != null) {
|
|
// CastPP here becomes control dependent on o2 ==
|
|
// null check above.
|
|
if (o.getClass() == Object.class) {
|
|
}
|
|
// This causes partial peeling. When that happens,
|
|
// the o2 == null check becomes redundant with the
|
|
// o3 != null check in the peeled iteration. The
|
|
// CastPP with o as input that was control
|
|
// dependent on the o2 == null check becomes
|
|
// control dependent on the o3 != null check,
|
|
// above the o != null check.
|
|
if (j > 7) {
|
|
|
|
}
|
|
j++;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|