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* [Bug tree-optimization/101754] New: Missed fold for a/b*b
@ 2021-08-03 14:00 llvm at rifkin dot dev
2021-08-04 5:54 ` [Bug tree-optimization/101754] " rguenth at gcc dot gnu.org
2021-12-16 0:19 ` pinskia at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: llvm at rifkin dot dev @ 2021-08-03 14:00 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101754
Bug ID: 101754
Summary: Missed fold for a/b*b
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: llvm at rifkin dot dev
Target Milestone: ---
GCC is not optimizing the following (contrived) divisibility check
https://godbolt.org/z/1rEhYa8Ts.
bool foo(int a, int b) {
return a/b*b == a;
}
bool bar(int a, int b) {
return a%b == 0;
}
If GCC can fold a/b*b into a-a%b, it will be able to optimize properly the rest
of the way.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/101754] Missed fold for a/b*b
2021-08-03 14:00 [Bug tree-optimization/101754] New: Missed fold for a/b*b llvm at rifkin dot dev
@ 2021-08-04 5:54 ` rguenth at gcc dot gnu.org
2021-12-16 0:19 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-08-04 5:54 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101754
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Keywords| |missed-optimization
Last reconfirmed| |2021-08-04
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/101754] Missed fold for a/b*b
2021-08-03 14:00 [Bug tree-optimization/101754] New: Missed fold for a/b*b llvm at rifkin dot dev
2021-08-04 5:54 ` [Bug tree-optimization/101754] " rguenth at gcc dot gnu.org
@ 2021-12-16 0:19 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-16 0:19 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101754
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-12-16 0:19 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-08-03 14:00 [Bug tree-optimization/101754] New: Missed fold for a/b*b llvm at rifkin dot dev
2021-08-04 5:54 ` [Bug tree-optimization/101754] " rguenth at gcc dot gnu.org
2021-12-16 0:19 ` pinskia at gcc dot gnu.org
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