[Bug target/54087] __atomic_fetch_add does not use xadd instruction

[drepper.fsp at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54087

--- Comment #6 from Ulrich Drepper <drepper.fsp at gmail dot com> 2012-08-03 
02:16:57 UTC ---
(In reply to comment #5)
> This patch introduces atomic_fetch_sub<mode>:

Seems to work nicely.