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* [gcc r13-4094] doc: fix description of -mrelax-cmpxchg-loop [PR 107676]
@ 2022-11-16 13:42 Alexander Monakov
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From: Alexander Monakov @ 2022-11-16 13:42 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:85966f0d20baf50a767ac1110f537395441604a9
commit r13-4094-g85966f0d20baf50a767ac1110f537395441604a9
Author: Alexander Monakov <amonakov@ispras.ru>
Date: Wed Nov 16 16:33:11 2022 +0300
doc: fix description of -mrelax-cmpxchg-loop [PR 107676]
gcc/ChangeLog:
PR target/107676
* doc/invoke.texi (-mrelax-cmpxchg-loop): Reword description.
Diff:
---
gcc/doc/invoke.texi | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index cbfe1102bd2..96f0b6d08bd 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -33561,10 +33561,11 @@ registers.
@item -mrelax-cmpxchg-loop
@opindex mrelax-cmpxchg-loop
-Relax cmpxchg loop by emitting an early load and compare before cmpxchg,
-execute pause if load value is not expected. This reduces excessive
-cachline bouncing when and works for all atomic logic fetch builtins
-that generates compare and swap loop.
+When emitting a compare-and-swap loop for @ref{__sync Builtins}
+and @ref{__atomic Builtins} lacking a native instruction, optimize
+for the highly contended case by issuing an atomic load before the
+@code{CMPXCHG} instruction, and using the @code{PAUSE} instruction
+to save CPU power when restarting the loop.
@item -mindirect-branch=@var{choice}
@opindex mindirect-branch
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2022-11-16 13:42 [gcc r13-4094] doc: fix description of -mrelax-cmpxchg-loop [PR 107676] Alexander Monakov
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