public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug tree-optimization/111631] New: Wrong code at -Os on x86_64-linux-gnu since r14-3217-g4d6132e5932
@ 2023-09-28 13:57 shaohua.li at inf dot ethz.ch
2023-09-28 15:15 ` [Bug tree-optimization/111631] [14 Regression] " pinskia at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: shaohua.li at inf dot ethz.ch @ 2023-09-28 13:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111631
Bug ID: 111631
Summary: Wrong code at -Os on x86_64-linux-gnu since
r14-3217-g4d6132e5932
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: shaohua.li at inf dot ethz.ch
CC: rguenth at gcc dot gnu.org
Target Milestone: ---
gcc at -Os produced the wrong code.
Bisected to r14-3217-g4d6132e5932
Compiler explorer: https://godbolt.org/z/Yj9bq1ecs
$ cat a.c
int printf(const char *, ...);
short a, f, i;
static const int *e;
short *g;
long h;
int main() {
{
unsigned j = i;
a = 1;
for (; a; a++) {
{
long b = j, d = h;
int c = 0;
while (d--)
*(char *)b++ = c;
}
if (e)
break;
}
j && (*g)--;
const int **k = &e;
*k = 0;
}
printf("%d\n", f);
}
$
$ gcc -O0 a.c && ./a.out
0
$ gcc -Os a.c && ./a.out
Segmentation fault
$ gcc -fsanitize=address,undefined a.c && ./a.out
0
$
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/111631] [14 Regression] Wrong code at -Os on x86_64-linux-gnu since r14-3217-g4d6132e5932
2023-09-28 13:57 [Bug tree-optimization/111631] New: Wrong code at -Os on x86_64-linux-gnu since r14-3217-g4d6132e5932 shaohua.li at inf dot ethz.ch
@ 2023-09-28 15:15 ` pinskia at gcc dot gnu.org
2023-09-28 15:17 ` pinskia at gcc dot gnu.org
2023-09-28 15:19 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-09-28 15:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111631
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |14.0
Summary|Wrong code at -Os on |[14 Regression] Wrong code
|x86_64-linux-gnu since |at -Os on x86_64-linux-gnu
|r14-3217-g4d6132e5932 |since r14-3217-g4d6132e5932
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/111631] [14 Regression] Wrong code at -Os on x86_64-linux-gnu since r14-3217-g4d6132e5932
2023-09-28 13:57 [Bug tree-optimization/111631] New: Wrong code at -Os on x86_64-linux-gnu since r14-3217-g4d6132e5932 shaohua.li at inf dot ethz.ch
2023-09-28 15:15 ` [Bug tree-optimization/111631] [14 Regression] " pinskia at gcc dot gnu.org
@ 2023-09-28 15:17 ` pinskia at gcc dot gnu.org
2023-09-28 15:19 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-09-28 15:17 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111631
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |DUPLICATE
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Same underlying issue as PR 111583.
*** This bug has been marked as a duplicate of bug 111583 ***
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/111631] [14 Regression] Wrong code at -Os on x86_64-linux-gnu since r14-3217-g4d6132e5932
2023-09-28 13:57 [Bug tree-optimization/111631] New: Wrong code at -Os on x86_64-linux-gnu since r14-3217-g4d6132e5932 shaohua.li at inf dot ethz.ch
2023-09-28 15:15 ` [Bug tree-optimization/111631] [14 Regression] " pinskia at gcc dot gnu.org
2023-09-28 15:17 ` pinskia at gcc dot gnu.org
@ 2023-09-28 15:19 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-09-28 15:19 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111631
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
ldist produces:
b_25 = (long int) j_23;
d_26 = h;
_8 = (sizetype) d_26;
_38 = (char *) b_25;
__builtin_memset (_38, 0, _8);
and also we have:
<bb 7> [local count: 13370358]:
if (j_23 != 0)
goto <bb 10>; [50.00%]
else
goto <bb 11>; [50.00%]
...
<bb 10> [local count: 6685179]:
g.10_9 = g;
_10 = *g.10_9;
_11 = (unsigned short) _10;
_12 = _11 + 65535;
_13 = (short int) _12;
*g.10_9 = _13;
But since d_26 is 0, originally there was no deferencing of _38 but now there
is and such.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-09-28 15:19 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-09-28 13:57 [Bug tree-optimization/111631] New: Wrong code at -Os on x86_64-linux-gnu since r14-3217-g4d6132e5932 shaohua.li at inf dot ethz.ch
2023-09-28 15:15 ` [Bug tree-optimization/111631] [14 Regression] " pinskia at gcc dot gnu.org
2023-09-28 15:17 ` pinskia at gcc dot gnu.org
2023-09-28 15:19 ` pinskia at gcc dot gnu.org
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).