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From: "wwwhhhyyy333 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/103069] cmpxchg isn't optimized
Date: Tue, 22 Feb 2022 03:38:01 +0000 [thread overview]
Message-ID: <bug-103069-4-iZxDlOxGVM@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-103069-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103069
--- Comment #13 from Hongyu Wang <wwwhhhyyy333 at gmail dot com> ---
All above glibc cases are now both relaxed by an load/cmp to skip cmpxchg under
-mrelax-cmpxchg-loop,
but for
> do
> {
> flags = THREAD_GETMEM (self, cancelhandling);
> newval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
> flags & ~SETXID_BITMASK, flags);
> }
> while (flags != newval);
If we want to optimize it to lock btc, we need to know the cmpxchg lies in a
loop. So it may require an extra pass to do further analysis and optimize,
which is not a good idea to do in stage 4.
next prev parent reply other threads:[~2022-02-22 3:38 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-03 19:08 [Bug target/103069] New: " hjl.tools at gmail dot com
2021-11-03 20:53 ` [Bug target/103069] " thiago at kde dot org
2021-11-04 21:25 ` thiago at kde dot org
2021-11-15 11:10 ` cvs-commit at gcc dot gnu.org
2021-11-15 14:26 ` hjl.tools at gmail dot com
2021-11-18 8:31 ` cvs-commit at gcc dot gnu.org
2022-01-24 23:49 ` hjl.tools at gmail dot com
2022-01-24 23:52 ` hjl.tools at gmail dot com
2022-01-24 23:53 ` hjl.tools at gmail dot com
2022-01-24 23:55 ` hjl.tools at gmail dot com
2022-01-25 0:04 ` thiago at kde dot org
2022-02-15 8:59 ` wwwhhhyyy333 at gmail dot com
2022-02-22 3:36 ` cvs-commit at gcc dot gnu.org
2022-02-22 3:38 ` wwwhhhyyy333 at gmail dot com [this message]
2022-02-22 4:16 ` thiago at kde dot org
2022-02-22 8:21 ` wwwhhhyyy333 at gmail dot com
2022-02-22 18:05 ` thiago at kde dot org
2022-02-22 18:41 ` jakub at gcc dot gnu.org
2022-02-22 20:25 ` thiago at kde dot org
2022-02-23 3:35 ` wwwhhhyyy333 at gmail dot com
2022-02-23 4:06 ` thiago at kde dot org
2022-04-13 8:18 ` cvs-commit at gcc dot gnu.org
2022-05-06 8:31 ` jakub at gcc dot gnu.org
2023-05-08 12:23 ` rguenth at gcc dot gnu.org
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