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/*
* Copyright (c) 2022, 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 8296389
* @summary Peeling of Irreducible loop can lead to NeverBranch being visited from either side
* @run main/othervm -Xcomp -XX:-TieredCompilation -XX:PerMethodTrapLimit=0
* -XX:CompileCommand=compileonly,TestPhaseCFGNeverBranchToGotoMain::test
* TestPhaseCFGNeverBranchToGotoMain
*/
/*
* @test
* @bug 8296389
* @compile TestPhaseCFGNeverBranchToGoto.jasm
* @summary Peeling of Irreducible loop can lead to NeverBranch being visited from either side
* @run main/othervm -Xcomp -XX:-TieredCompilation -XX:PerMethodTrapLimit=0
* -XX:CompileCommand=compileonly,TestPhaseCFGNeverBranchToGoto::test
* TestPhaseCFGNeverBranchToGoto
*/
public class TestPhaseCFGNeverBranchToGotoMain {
public static void main (String[] args) {
test(false, false);
}
public static void test(boolean flag1, boolean flag2) {
if (flag1) { // runtime check, avoid infinite loop
int a = 77;
int b = 0;
do { // empty loop
a--;
b++;
} while (a > 0);
// a == 0, b == 77 - after first loop-opts phase
int p = 0;
for (int i = 0; i < 4; i++) {
if ((i % 2) == 0) {
p = 1;
}
}
// p == 1 - after second loop-opts phase (via unrolling)
// in first loop-opts phase we have 2x unrolling, 4x after second
int x = 1;
if (flag2) {
x = 3;
} // have region here, so that NeverBranch does not get removed
do { // infinite loop
do {
// NeverBranch inserted here, during loop-opts 1
x *= 2;
if (p == 0) { // reason for peeling in loop-opts 1
// after we know that p == 1, we lose this exit
break;
}
// once we know that b == 77, we lose exit
} while (b == 77);
// after we lost both exits above, this loop gets cut off
int y = 5;
do {
y *= 3;
} while (b == 77);
} while (true);
}
}
}
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