[Bug tree-optimization/86865] New: [9 Regression] Wrong code w/ -O2 -floop-parallelize-all -fstack-reuse=none -fwrapv -fno-tree-ch -fno-tree-dce -fno-tree-dominator-opts -fno-tree-loop-ivcanon
asolokha at gmx dot com
gcc-bugzilla@gcc.gnu.org
Mon Aug 6 11:11:00 GMT 2018
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86865
Bug ID: 86865
Summary: [9 Regression] Wrong code w/ -O2
-floop-parallelize-all -fstack-reuse=none -fwrapv
-fno-tree-ch -fno-tree-dce -fno-tree-dominator-opts
-fno-tree-loop-ivcanon
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: asolokha at gmx dot com
Target Milestone: ---
gcc-9.0.0-alpha20180729 snapshot (r263055) generates wrong code when compiling
the following snippet w/ -O2 -floop-parallelize-all -fstack-reuse=none -fwrapv
-fno-tree-ch -fno-tree-dce -fno-tree-dominator-opts -fno-tree-loop-ivcanon:
int xy, tb;
void
bt (void)
{
for (xy = 0; xy >= 0; --xy)
{
int yt[8] = { 0 };
int pz[2] = { 0 };
int sa[32] = { 0 };
int us;
for (us = 0; us < 8; ++us)
yt[us] = 0;
(void) yt;
(void) pz;
(void) sa;
}
tb = 1;
}
int
main (void)
{
bt ();
if (xy != -1)
__builtin_abort ();
return 0;
}
% gcc-9.0.0-alpha20180729 -O2 jdoeqjdo.c -o good && ./good
% echo $?
0
% gcc-9.0.0-alpha20180729 -O2 -floop-parallelize-all -fstack-reuse=none -fwrapv
-fno-tree-ch -fno-tree-dce -fno-tree-dominator-opts -fno-tree-loop-ivcanon
jdoeqjdo.c -o bad && ./bad
zsh: abort (core dumped) ./bad
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