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/*
* Copyright (c) 2019, Oracle and/or its affiliates. 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
* @bug 8235452
* @library /test/lib /
* @summary Test loop strip mining verification with dying outer loop.
* @run main/othervm -Xbatch -XX:-TieredCompilation
* compiler.loopstripmining.TestDeadOuterStripMinedLoop
*/
package compiler.loopstripmining;
import jdk.test.lib.Asserts;
public class TestDeadOuterStripMinedLoop {
public static int test(boolean b) {
int res = 5000;
for (int i = 0; i < 42; i++) {
if (!b) {
break;
}
// Strip mined loop
while (--res > 0) {
if (res < 1) {
throw new RuntimeException("Should not reach here!");
}
}
/*
After parsing:
Loop:
res--;
if (res <= 0) {
goto End;
}
if (res < 1) { <- Treated as loop exit check (res <= 0)
UncommonTrap();
}
goto Loop;
End:
Loop opts convert this into:
// Outer strip mined loop
do {
// Strip mined loop
do {
res--;
if (res <= 0) {
goto End;
}
} while (res > 0); <- Always false due to above res <= 0 check
Safepoint()
} while (false);
UncommonTrap();
End:
The safepoint path dies, because the exit condition of the strip mined loop is always false:
// Strip mined loop
do {
res--;
if (res <= 0) {
goto End;
}
} while (true);
End:
*/
}
return res;
}
public static void main(String[] args) {
for (int i = 0; i < 100; i++) {
Asserts.assertEQ(test(true), -41);
}
Asserts.assertEQ(test(false), 5000);
}
}
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