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* [Bug target/102672] New: [AArch64] Failure to optimize to using stp instead of 2 strs when possible
@ 2021-10-09 21:01 gabravier at gmail dot com
  2021-10-09 21:10 ` [Bug target/102672] " pinskia at gcc dot gnu.org
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: gabravier at gmail dot com @ 2021-10-09 21:01 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102672

            Bug ID: 102672
           Summary: [AArch64] Failure to optimize to using stp instead of
                    2 strs when possible
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gabravier at gmail dot com
  Target Milestone: ---

struct X {
    int i;
    void *p;
};

void foo(struct X *q, void *p)
{
    struct X b{};
    b.p = p;
    *q = b;
}

With -O3, GCC outputs this:

foo(X*, void*):
        str     wzr, [x0]
        str     x1, [x0, 8]
        ret

LLVM instead outputs this:

foo(X*, void*):
        stp     xzr, x1, [x0]
        ret

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

* [Bug target/102672] [AArch64] Failure to optimize to using stp instead of 2 strs when possible
  2021-10-09 21:01 [Bug target/102672] New: [AArch64] Failure to optimize to using stp instead of 2 strs when possible gabravier at gmail dot com
@ 2021-10-09 21:10 ` pinskia at gcc dot gnu.org
  2021-10-09 21:10 ` pinskia at gcc dot gnu.org
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-10-09 21:10 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102672

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Padding bytes are not zero in some cases and this is the case here.

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

* [Bug target/102672] [AArch64] Failure to optimize to using stp instead of 2 strs when possible
  2021-10-09 21:01 [Bug target/102672] New: [AArch64] Failure to optimize to using stp instead of 2 strs when possible gabravier at gmail dot com
  2021-10-09 21:10 ` [Bug target/102672] " pinskia at gcc dot gnu.org
@ 2021-10-09 21:10 ` pinskia at gcc dot gnu.org
  2021-10-09 21:17 ` pinskia at gcc dot gnu.org
  2021-10-10 20:06 ` pinskia at gcc dot gnu.org
  3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-10-09 21:10 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102672

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
There might be another bugs similar to this already too.

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

* [Bug target/102672] [AArch64] Failure to optimize to using stp instead of 2 strs when possible
  2021-10-09 21:01 [Bug target/102672] New: [AArch64] Failure to optimize to using stp instead of 2 strs when possible gabravier at gmail dot com
  2021-10-09 21:10 ` [Bug target/102672] " pinskia at gcc dot gnu.org
  2021-10-09 21:10 ` pinskia at gcc dot gnu.org
@ 2021-10-09 21:17 ` pinskia at gcc dot gnu.org
  2021-10-10 20:06 ` pinskia at gcc dot gnu.org
  3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-10-09 21:17 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102672

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 target/102672] [AArch64] Failure to optimize to using stp instead of 2 strs when possible
  2021-10-09 21:01 [Bug target/102672] New: [AArch64] Failure to optimize to using stp instead of 2 strs when possible gabravier at gmail dot com
                   ` (2 preceding siblings ...)
  2021-10-09 21:17 ` pinskia at gcc dot gnu.org
@ 2021-10-10 20:06 ` pinskia at gcc dot gnu.org
  3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-10-10 20:06 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102672

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-10-10
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
         Depends on|                            |82142

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
PR 82142 is simular.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82142
[Bug 82142] struct zeroing should use wide stores instead of avoiding
overwriting padding

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

end of thread, other threads:[~2021-10-10 20:06 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-10-09 21:01 [Bug target/102672] New: [AArch64] Failure to optimize to using stp instead of 2 strs when possible gabravier at gmail dot com
2021-10-09 21:10 ` [Bug target/102672] " pinskia at gcc dot gnu.org
2021-10-09 21:10 ` pinskia at gcc dot gnu.org
2021-10-09 21:17 ` pinskia at gcc dot gnu.org
2021-10-10 20:06 ` pinskia at gcc dot gnu.org

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