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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/98737] Atomic operation on x86 no optimized to use flags
Date: Tue, 19 Jan 2021 10:01:42 +0000	[thread overview]
Message-ID: <bug-98737-4-h2XfopcrTa@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-98737-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98737

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
That peephole handles only constants, i.e.
_Bool h(void)
{
  return __sync_fetch_and_add(&a, -32) == 32;
}

_Bool i(void)
{
  return __sync_fetch_and_add(&a, 64) == -64;
}

Anyway, for #c0 the peephole2 would need to match because it is op_fetch rather
than fetch_op the UNSPEC_XCHG followed by the operation again followed by
comparison.

  parent reply	other threads:[~2021-01-19 10:01 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-18 19:59 [Bug target/98737] New: " drepper.fsp+rhbz at gmail dot com
2021-01-19  7:55 ` [Bug target/98737] " rguenth at gcc dot gnu.org
2021-01-19  8:37 ` ubizjak at gmail dot com
2021-01-19  9:53 ` redi at gcc dot gnu.org
2021-01-19 10:01 ` jakub at gcc dot gnu.org [this message]
2021-01-26 15:09 ` jakub at gcc dot gnu.org
2021-01-26 16:45 ` drepper.fsp+rhbz at gmail dot com
2021-01-26 17:11 ` jakub at gcc dot gnu.org
2021-01-26 20:10 ` drepper.fsp+rhbz at gmail dot com
2021-12-14 10:20 ` jakub at gcc dot gnu.org
2022-01-03 13:17 ` cvs-commit at gcc dot gnu.org
2022-01-12 15:50 ` jakub at gcc dot gnu.org
2022-01-14 11:07 ` cvs-commit at gcc dot gnu.org

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