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* [Bug tree-optimization/95176] New: Failure to optimize division followed by multiplication to modulo followed by subtraction
@ 2020-05-17 17:13 gabravier at gmail dot com
  2020-05-17 17:25 ` [Bug tree-optimization/95176] " pinskia at gcc dot gnu.org
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: gabravier at gmail dot com @ 2020-05-17 17:13 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95176

            Bug ID: 95176
           Summary: Failure to optimize division followed by
                    multiplication to modulo followed by subtraction
           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: ---

int f(int a, int b)
{
    return a * (b / a);
}

This is equivalent to `return b - (b % a);`. This transformation is done by
LLVM, but not by GCC.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* [Bug tree-optimization/95176] Failure to optimize division followed by multiplication to modulo followed by subtraction
  2020-05-17 17:13 [Bug tree-optimization/95176] New: Failure to optimize division followed by multiplication to modulo followed by subtraction gabravier at gmail dot com
@ 2020-05-17 17:25 ` pinskia at gcc dot gnu.org
  2020-05-18  6:28 ` rguenth at gcc dot gnu.org
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2020-05-17 17:25 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95176

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement

^ permalink raw reply	[flat|nested] 5+ messages in thread

* [Bug tree-optimization/95176] Failure to optimize division followed by multiplication to modulo followed by subtraction
  2020-05-17 17:13 [Bug tree-optimization/95176] New: Failure to optimize division followed by multiplication to modulo followed by subtraction gabravier at gmail dot com
  2020-05-17 17:25 ` [Bug tree-optimization/95176] " pinskia at gcc dot gnu.org
@ 2020-05-18  6:28 ` rguenth at gcc dot gnu.org
  2021-08-12 14:09 ` arjun.is at lostca dot se
  2021-08-24 19:51 ` arjun.is at lostca dot se
  3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-05-18  6:28 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95176

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
           Keywords|                            |easyhack
   Last reconfirmed|                            |2020-05-18
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* [Bug tree-optimization/95176] Failure to optimize division followed by multiplication to modulo followed by subtraction
  2020-05-17 17:13 [Bug tree-optimization/95176] New: Failure to optimize division followed by multiplication to modulo followed by subtraction gabravier at gmail dot com
  2020-05-17 17:25 ` [Bug tree-optimization/95176] " pinskia at gcc dot gnu.org
  2020-05-18  6:28 ` rguenth at gcc dot gnu.org
@ 2021-08-12 14:09 ` arjun.is at lostca dot se
  2021-08-24 19:51 ` arjun.is at lostca dot se
  3 siblings, 0 replies; 5+ messages in thread
From: arjun.is at lostca dot se @ 2021-08-12 14:09 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95176

Arjun Shankar <arjun.is at lostca dot se> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |arjun.is at lostca dot se

--- Comment #2 from Arjun Shankar <arjun.is at lostca dot se> ---
This appears to have been fixed as bug 96696 via the following commit:

https://gcc.gnu.org/g:3dcd1334b4f522352b80814513fdca902fc2a207

^ permalink raw reply	[flat|nested] 5+ messages in thread

* [Bug tree-optimization/95176] Failure to optimize division followed by multiplication to modulo followed by subtraction
  2020-05-17 17:13 [Bug tree-optimization/95176] New: Failure to optimize division followed by multiplication to modulo followed by subtraction gabravier at gmail dot com
                   ` (2 preceding siblings ...)
  2021-08-12 14:09 ` arjun.is at lostca dot se
@ 2021-08-24 19:51 ` arjun.is at lostca dot se
  3 siblings, 0 replies; 5+ messages in thread
From: arjun.is at lostca dot se @ 2021-08-24 19:51 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95176

Arjun Shankar <arjun.is at lostca dot se> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
   Target Milestone|---                         |12.0
         Resolution|---                         |FIXED

--- Comment #3 from Arjun Shankar <arjun.is at lostca dot se> ---
This should make it to GCC 12 when it's released, so I'm closing it
accordingly.

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-08-24 19:51 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-17 17:13 [Bug tree-optimization/95176] New: Failure to optimize division followed by multiplication to modulo followed by subtraction gabravier at gmail dot com
2020-05-17 17:25 ` [Bug tree-optimization/95176] " pinskia at gcc dot gnu.org
2020-05-18  6:28 ` rguenth at gcc dot gnu.org
2021-08-12 14:09 ` arjun.is at lostca dot se
2021-08-24 19:51 ` arjun.is at lostca dot se

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