jdk-24/test/hotspot/jtreg/compiler/loopopts/TestUndetectedLoopInInfiniteLoop.java
2022-12-14 17:25:49 +00:00

63 lines
2.5 KiB
Java

/*
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* 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
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*
* 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.
*
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*/
/*
* @test
* @bug 8296318
* @summary Loops inside infinite loops may not be detected, thus a region may still
* be the loop head, even if it is not a LoopNode.
* @run main/othervm -Xcomp -XX:-TieredCompilation
* -XX:CompileCommand=compileonly,TestUndetectedLoopInInfiniteLoop::test*
* -XX:PerMethodTrapLimit=0
* TestUndetectedLoopInInfiniteLoop
*/
public class TestUndetectedLoopInInfiniteLoop {
public static void main (String[] args) {
test(true, false);
}
public static void test(boolean flag, boolean flag2) {
int x = 0;
if (flag2) { // runtime check, avoid infinite loop
while (true) { // infinite loop (no exit)
if (flag) {
x++;
}
do { // inner loop
// assert for this block
// Region
// Phi -> SubI -> XorI ---> Phi
x = (x - 1) ^ 1;
// Problem: this looks like a loop, but we have no LoopNode
// We have no LoopNode, because this is all in an infinite
// loop, and during PhaseIdealLoop::build_loop_tree we do not
// attach the loops of an infinite loop to the loop tree,
// and hence we do not get to call beautify_loop on these loops
// which would have turned the Region into a LoopNode.
} while (x < 0);
}
}
}
}