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* [Bug c/110427] New: a<a-- will be satisfied in gcc 9 and gcc 11
@ 2023-06-27 7:49 qurong at ios dot ac.cn
2023-06-27 8:02 ` [Bug c/110427] " arsen at gcc dot gnu.org
2023-06-27 8:14 ` schwab@linux-m68k.org
0 siblings, 2 replies; 3+ messages in thread
From: qurong at ios dot ac.cn @ 2023-06-27 7:49 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110427
Bug ID: 110427
Summary: a<a-- will be satisfied in gcc 9 and gcc 11
Product: gcc
Version: 9.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: qurong at ios dot ac.cn
Target Milestone: ---
The output of the following c program is 1 in gcc while it is -1 in clang,
Maybe -1 is the expected output for this program.
#include <stdio.h>
int main() {
int a = 0;
if (a < a--) {
a = 1;
}
printf("%d\n", a);
return 0;
}
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c/110427] a<a-- will be satisfied in gcc 9 and gcc 11
2023-06-27 7:49 [Bug c/110427] New: a<a-- will be satisfied in gcc 9 and gcc 11 qurong at ios dot ac.cn
@ 2023-06-27 8:02 ` arsen at gcc dot gnu.org
2023-06-27 8:14 ` schwab@linux-m68k.org
1 sibling, 0 replies; 3+ messages in thread
From: arsen at gcc dot gnu.org @ 2023-06-27 8:02 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110427
Arsen Arsenović <arsen at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |arsen at gcc dot gnu.org
--- Comment #1 from Arsen Arsenović <arsen at gcc dot gnu.org> ---
<source>: In function 'main':
<source>:4:18: warning: operation on 'a' may be undefined [-Wsequence-point]
4 | if (a < a--) {
| ~^~
the result is simply undefined (is the first `a' pre- or post-decrement?)
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c/110427] a<a-- will be satisfied in gcc 9 and gcc 11
2023-06-27 7:49 [Bug c/110427] New: a<a-- will be satisfied in gcc 9 and gcc 11 qurong at ios dot ac.cn
2023-06-27 8:02 ` [Bug c/110427] " arsen at gcc dot gnu.org
@ 2023-06-27 8:14 ` schwab@linux-m68k.org
1 sibling, 0 replies; 3+ messages in thread
From: schwab@linux-m68k.org @ 2023-06-27 8:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110427
Andreas Schwab <schwab@linux-m68k.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #2 from Andreas Schwab <schwab@linux-m68k.org> ---
The behaviour is undefined.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-06-27 8:14 UTC | newest]
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2023-06-27 7:49 [Bug c/110427] New: a<a-- will be satisfied in gcc 9 and gcc 11 qurong at ios dot ac.cn
2023-06-27 8:02 ` [Bug c/110427] " arsen at gcc dot gnu.org
2023-06-27 8:14 ` schwab@linux-m68k.org
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