[PATCH] doc: Reword the description of -mrelax-cmpxchg-loop [PR 107676]

[Hongyu Wang <hongyu.wang@intel.com>]

Hi,

According to PR 107676, the document of -mrelax-cmpxchg-loop is nonsensical.
Adjust the wording according to the comments.

Bootstrapped on x86_64-pc-linux-gnu, ok for trunk?

gcc/ChangeLog:

	PR target/107676
	* doc/invoke.texi: Reword the description of
	-mrelax-cmpxchg-loop.
---
 gcc/doc/invoke.texi | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 40f667a630a..bdd7c319aef 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -33805,10 +33805,12 @@ 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.
+For compare and swap loops that emitted by some __atomic_* builtins
+(e.g. __atomic_fetch_(or|and|xor|nand) and their __atomic_*_fetch
+counterparts), emit an atomic load before cmpxchg instruction. If the
+loaded value is not equal to expected, execute a pause instead of
+directly run the cmpxchg instruction. This might reduce excessive
+cacheline bouncing.
 
 @item -mindirect-branch=@var{choice}
 @opindex mindirect-branch
-- 
2.18.1