public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug tree-optimization/107005] New: gcc not exploiting undefined behavior to optimize away the result of division
@ 2022-09-21 21:41 hiraditya at msn dot com
2022-09-21 21:46 ` [Bug tree-optimization/107005] " pinskia at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: hiraditya at msn dot com @ 2022-09-21 21:41 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107005
Bug ID: 107005
Summary: gcc not exploiting undefined behavior to optimize away
the result of division
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: hiraditya at msn dot com
Target Milestone: ---
#include <limits.h>
int main() { return INT_MIN / -1; }
gcc -O2
main:
mov eax, -2147483648
ret
clang -O2
main: # @main
ret
https://godbolt.org/z/Tjxx3KGdK
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/107005] gcc not exploiting undefined behavior to optimize away the result of division
2022-09-21 21:41 [Bug tree-optimization/107005] New: gcc not exploiting undefined behavior to optimize away the result of division hiraditya at msn dot com
@ 2022-09-21 21:46 ` pinskia at gcc dot gnu.org
2022-09-21 21:47 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-09-21 21:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107005
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
That is because GCC constants folds INT_MIN / -1 into INT_MIN.
GCC warns about this code for this expression while clang does not ...
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/107005] gcc not exploiting undefined behavior to optimize away the result of division
2022-09-21 21:41 [Bug tree-optimization/107005] New: gcc not exploiting undefined behavior to optimize away the result of division hiraditya at msn dot com
2022-09-21 21:46 ` [Bug tree-optimization/107005] " pinskia at gcc dot gnu.org
@ 2022-09-21 21:47 ` pinskia at gcc dot gnu.org
2022-09-22 6:53 ` rguenth at gcc dot gnu.org
2022-09-22 20:04 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-09-21 21:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107005
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Even ICC warns ....
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/107005] gcc not exploiting undefined behavior to optimize away the result of division
2022-09-21 21:41 [Bug tree-optimization/107005] New: gcc not exploiting undefined behavior to optimize away the result of division hiraditya at msn dot com
2022-09-21 21:46 ` [Bug tree-optimization/107005] " pinskia at gcc dot gnu.org
2022-09-21 21:47 ` pinskia at gcc dot gnu.org
@ 2022-09-22 6:53 ` rguenth at gcc dot gnu.org
2022-09-22 20:04 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-09-22 6:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107005
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |WONTFIX
Keywords| |missed-optimization
Status|UNCONFIRMED |RESOLVED
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
I wonder what's the point of the clang result? I'd say it's quite bad QOI.
So I think there's nothing to fix here.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/107005] gcc not exploiting undefined behavior to optimize away the result of division
2022-09-21 21:41 [Bug tree-optimization/107005] New: gcc not exploiting undefined behavior to optimize away the result of division hiraditya at msn dot com
` (2 preceding siblings ...)
2022-09-22 6:53 ` rguenth at gcc dot gnu.org
@ 2022-09-22 20:04 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-09-22 20:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107005
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 107011 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-09-22 20:04 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-09-21 21:41 [Bug tree-optimization/107005] New: gcc not exploiting undefined behavior to optimize away the result of division hiraditya at msn dot com
2022-09-21 21:46 ` [Bug tree-optimization/107005] " pinskia at gcc dot gnu.org
2022-09-21 21:47 ` pinskia at gcc dot gnu.org
2022-09-22 6:53 ` rguenth at gcc dot gnu.org
2022-09-22 20:04 ` 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).