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* [Bug target/95751] New: [aarch64] Consider using ldapr for __atomic_load_n(acquire) on ARMv8.3-RCPC
@ 2020-06-18 20:07 andysem at mail dot ru
2022-12-20 10:06 ` [Bug target/95751] " ktkachov at gcc dot gnu.org
2023-09-07 14:16 ` wilco at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: andysem at mail dot ru @ 2020-06-18 20:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95751
Bug ID: 95751
Summary: [aarch64] Consider using ldapr for
__atomic_load_n(acquire) on ARMv8.3-RCPC
Product: gcc
Version: 10.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: andysem at mail dot ru
Target Milestone: ---
ARMv8.3-RCPC extension adds new ldapr[b/h] instructions for Load-AcquirePC
semantics that better matches C++ memory order semantics.
In particular, the core ldar instructions will wait until the previous stlr,
even on another address, completes on the same thread. The newer ldapr does not
wait for the previous stlr to complete, unless it is performed on the same
address.
Consider using these new instructions in __atomic_load_n(consume/acquire) when
-march=armv8.3 or higher is specified. Note that __atomic_load_n(relaxed) and
__atomic_load_n(seq_cst) should stay unchanged.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/95751] [aarch64] Consider using ldapr for __atomic_load_n(acquire) on ARMv8.3-RCPC
2020-06-18 20:07 [Bug target/95751] New: [aarch64] Consider using ldapr for __atomic_load_n(acquire) on ARMv8.3-RCPC andysem at mail dot ru
@ 2022-12-20 10:06 ` ktkachov at gcc dot gnu.org
2023-09-07 14:16 ` wilco at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: ktkachov at gcc dot gnu.org @ 2022-12-20 10:06 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95751
ktkachov at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ktkachov at gcc dot gnu.org
Ever confirmed|0 |1
Last reconfirmed| |2022-12-20
Status|UNCONFIRMED |NEW
--- Comment #1 from ktkachov at gcc dot gnu.org ---
I had not seen this report at the time, but LDAPR generation has now been
implemented in GCC 13.1 for acquire loads with
https://gcc.gnu.org/g:0431e8ae5bdb854bda5f9005e41c8c4d03f6d74e and follow-ups.
Any testing/evaluation/feedback would be welcome
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/95751] [aarch64] Consider using ldapr for __atomic_load_n(acquire) on ARMv8.3-RCPC
2020-06-18 20:07 [Bug target/95751] New: [aarch64] Consider using ldapr for __atomic_load_n(acquire) on ARMv8.3-RCPC andysem at mail dot ru
2022-12-20 10:06 ` [Bug target/95751] " ktkachov at gcc dot gnu.org
@ 2023-09-07 14:16 ` wilco at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: wilco at gcc dot gnu.org @ 2023-09-07 14:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95751
Wilco <wilco at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |wilco at gcc dot gnu.org
Resolution|--- |FIXED
Status|NEW |RESOLVED
Target Milestone|--- |13.0
--- Comment #2 from Wilco <wilco at gcc dot gnu.org> ---
Fixed in GCC13.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-09-07 14:16 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2020-06-18 20:07 [Bug target/95751] New: [aarch64] Consider using ldapr for __atomic_load_n(acquire) on ARMv8.3-RCPC andysem at mail dot ru
2022-12-20 10:06 ` [Bug target/95751] " ktkachov at gcc dot gnu.org
2023-09-07 14:16 ` wilco at gcc dot gnu.org
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