https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97309
--- Comment #1 from qinzhao at gcc dot gnu.org ---
proposed patch:
Subject: [PATCH] PR97309--improve documentation of -fallow-store-data-races
---
gcc/doc/invoke.texi | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 7c81d7f41bd..926ee1ff28e 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -11621,7 +11621,18 @@ Do not remove unused C++ allocations in dead code
elimination.
@item -fallow-store-data-races
@opindex fallow-store-data-races
-Allow the compiler to introduce new data races on stores.
+Allow the compiler to perform optimizations that may introduce new data races
+on stores, without proving that the variable cannot be concurrently accessed
+by other threads. Does not affect optimization of local data. It is safe to
+use this option if it is known that global data will not be accessed by
+multiple threads.
+
+Examples of optimizations enabled by @option{-fallow-store-data-races} include
+hoisting or if-conversions that may cause a value that was already in memory
+to be re-written with that same value. Such re-writing is safe in a single
+threaded context but may be unsafe in a multi-threaded context. Note that on
+some processors, if-conversions may be required in order to enable
+vectorization.
Enabled at level @option{-Ofast}.
--
2.11.0
