https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83255
Bug ID: 83255
Summary: [8 Regression] [graphite] Wrong code w/ -O1
-floop-nest-optimize
Product: gcc
Version: 8.0
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-8.0.0-alpha20171126 snapshot (r255155) produces wrong code w/ -O1 (-O2,
-O3, -Ofast) -floop-nest-optimize for the following snippet:
int rx, in;
int
main (void)
{
const int tj = 3;
int as[tj];
static int l4;
while (l4 < 1)
{
for (rx = 0; rx < tj; ++rx)
{
for (in = 0; in < tj; ++in)
as[in] = 1;
as[rx] = 0;
}
++l4;
}
return as[tj - 1];
}
% gcc-8.0.0-alpha20171126 -O1 -o good znyz2wee.c && ./good
% echo $?
0
% gcc-8.0.0-alpha20171126 -O1 -floop-nest-optimize -o bad znyz2wee.c && ./bad
zsh: exit 1 ./bad
% echo $?
1
