[Bug libstdc++/51798] [4.7 regression] libstdc++ atomicity performance regression due to __sync_fetch_and_add

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51798

--- Comment #24 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-01-27 
20:26:12 UTC ---
Author: jakub
Date: Fri Jan 27 20:26:03 2012
New Revision: 183644

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=183644
Log:
    PR libstdc++/51798
    * config/cpu/generic/atomicity_builtins/atomicity.h
    (__exchange_and_add, __atomic_add): Use __atomic_fetch_add
    with __ATOMIC_ACQ_REL semantics instead of __sync_fetch_and_add.
    * include/ext/atomicity.h (__exchange_and_add, __atomic_add):
    Likewise.

Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/config/cpu/generic/atomicity_builtins/atomicity.h
    trunk/libstdc++-v3/include/ext/atomicity.h