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* [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
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