[Bug c++/60272] atomic<>::compare_exchange_weak has spurious store and can cause race conditions

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60272

--- Comment #6 from Richard Henderson <rth at gcc dot gnu.org> ---
Author: rth
Date: Fri Feb 21 00:14:05 2014
New Revision: 207973

URL: http://gcc.gnu.org/viewcvs?rev=207973&root=gcc&view=rev
Log:
PR c++/60272

gcc/
    * builtins.c (expand_builtin_atomic_compare_exchange): Conditionalize
    on failure the store back into EXPECT.
libatomic/
    * cas_n.c (libat_compare_exchange): Conditionalize on failure
    the store back to EPTR.

Modified:
    branches/gcc-4_8-branch/gcc/ChangeLog
    branches/gcc-4_8-branch/gcc/builtins.c
    branches/gcc-4_8-branch/libatomic/ChangeLog
    branches/gcc-4_8-branch/libatomic/cas_n.c