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From: "phosit at autistici dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/86072] Poor codegen with atomics
Date: Fri, 22 Dec 2023 20:30:20 +0000 [thread overview]
Message-ID: <bug-86072-4-00u3cIBUN7@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-86072-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86072
Phosit <phosit at autistici dot org> changed:
What |Removed |Added
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CC| |phosit at autistici dot org
--- Comment #4 from Phosit <phosit at autistici dot org> ---
(In reply to Richard Biener from comment #2)
> Somebody has to decide if it's worth optimizing them and has to sit down and
> exactly specify what kind of optimizations are valid.
There is a paper about the optimization of atomics. It might not be detailed
enough.
https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4455.html
Note that the memory-model changed a bit since the release of that paper.
> I guess it's worth optimizing them if these cases appear in real-world code
> (and then we'd like to see examples).
std::shared_ptr use fetch_add and fetch_sub. When a std::shared_ptr is not used
for syncronization this optimization could take effect.
PR 48987 is specifically about combining multiple fetch_add and fetch_sub.
parent reply other threads:[~2023-12-22 20:30 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <bug-86072-4@http.gcc.gnu.org/bugzilla/>]
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