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* [Bug tree-optimization/98907] New: Failure to optimize abs pattern
@ 2021-02-01 7:48 gabravier at gmail dot com
2021-02-02 7:56 ` [Bug tree-optimization/98907] " rguenth at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: gabravier at gmail dot com @ 2021-02-01 7:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98907
Bug ID: 98907
Summary: Failure to optimize abs pattern
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: gabravier at gmail dot com
Target Milestone: ---
int32_t f(int32_t x)
{
return ((x >> 31) | 1) * x;
}
This can be optimized into `return __builtin_abs(x);` (where sizeof(int) ==
sizeof(int32_t)). This transformation is done by LLVM, but not GCC.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/98907] Failure to optimize abs pattern
2021-02-01 7:48 [Bug tree-optimization/98907] New: Failure to optimize abs pattern gabravier at gmail dot com
@ 2021-02-02 7:56 ` rguenth at gcc dot gnu.org
2021-07-25 5:50 ` pinskia at gcc dot gnu.org
2023-09-04 9:10 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-02-02 7:56 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98907
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2021-02-02
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/98907] Failure to optimize abs pattern
2021-02-01 7:48 [Bug tree-optimization/98907] New: Failure to optimize abs pattern gabravier at gmail dot com
2021-02-02 7:56 ` [Bug tree-optimization/98907] " rguenth at gcc dot gnu.org
@ 2021-07-25 5:50 ` pinskia at gcc dot gnu.org
2023-09-04 9:10 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-07-25 5:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98907
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
What LLVM does is the following:
((x >> 31) | 1) * x;
Convert (x >> 31) into -(x < 0)
(-(x < 0)) | -> x < 0 ? -1 : 1
(x < 0 ? -1 : 1) *x -> x < 0 ? -x : x
Now we could do the same I don't know to do this way or another way.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/98907] Failure to optimize abs pattern
2021-02-01 7:48 [Bug tree-optimization/98907] New: Failure to optimize abs pattern gabravier at gmail dot com
2021-02-02 7:56 ` [Bug tree-optimization/98907] " rguenth at gcc dot gnu.org
2021-07-25 5:50 ` pinskia at gcc dot gnu.org
@ 2023-09-04 9:10 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-09-04 9:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98907
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot gnu.org
Status|NEW |ASSIGNED
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Mine,
bug 110009 comment #3 has the patch for this and that one.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-09-04 9:10 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-02-01 7:48 [Bug tree-optimization/98907] New: Failure to optimize abs pattern gabravier at gmail dot com
2021-02-02 7:56 ` [Bug tree-optimization/98907] " rguenth at gcc dot gnu.org
2021-07-25 5:50 ` pinskia at gcc dot gnu.org
2023-09-04 9:10 ` pinskia at gcc dot gnu.org
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