diff mbox series

[7/8,RFC] Mention floating point atomic fetch_add etc in docs

Message ID 20240919131204.3865854-8-mmalcomson@nvidia.com
State New
Headers
Series Introduce floating point fetch_add builtins |

Checks

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Commit Message

Matthew Malcomson Sept. 19, 2024, 1:12 p.m. UTC 
  From: Matthew Malcomson <mmalcomson@nvidia.com>

Signed-off-by: Matthew Malcomson <mmalcomson@nvidia.com>
---
 gcc/doc/extend.texi | 12 ++++++++++++
 1 file changed, 12 insertions(+)
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Patch

diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 66c99ef7a66..a3e3e7da5d6 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -13501,6 +13501,18 @@  the same format with the addition of a @samp{size_t} parameter inserted
 as the first parameter indicating the size of the object being pointed to.
 All objects must be the same size.
 
+Moreover, the @samp{__atomic_fetch_add}, @samp{__atomic_fetch_sub},
+@samp{__atomic_add_fetch} and @samp{__atomic_sub_fetch} builtins can all
+accept floating point types of @code{float}, @code{double}, @code{long double},
+@code{bfloat16}, @code{_Float16}, @code{_Float32}, @code{_Float64},
+@code{_Float128}, @code{_Float32x} and @code{_Float64x}.  These use a lock-free
+built-in function if the size of the floating point type makes that possible
+and otherwise leave an external call to be resolved at run time.  This external
+call is of the same format but specialised to the given floating point type.
+The specialised versions of these functions are denoted by one of the
+suffixes @code{_fpf}, @code{_fp}, @code{_fpl}, @code{_fpf16b}, @code{_fpf16},
+@code{_fpf32}, @code{_fpf64}, @code{_fpf128}, @code{_fpf32x}, @code{_fpf64x}.
+
 There are 6 different memory orders that can be specified.  These map
 to the C++11 memory orders with the same names, see the C++11 standard
 or the @uref{https://gcc.gnu.org/wiki/Atomic/GCCMM/AtomicSync,GCC wiki