https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66200
--- Comment #4 from Sharad Singhai <singhai at gcc dot gnu.org> --- Author: singhai Date: Tue Jun 9 06:45:43 2015 New Revision: 224265 URL: https://gcc.gnu.org/viewcvs?rev=224265&root=gcc&view=rev Log: Backport r224118 from trunk for Google ref b/20542176 and b/20766120. Remove TARGET_RELAXED_ORDERING and optimize for weak memory models. This patch removes the special casing for targets with relaxed memory ordering and handles guard accesses with equivalent atomic load acquire operations. In this process we change the algorithm to load the guard variable with an atomic load that has ACQUIRE semantics. This then means that on targets which have weak memory models, the fast path is inlined and can directly use a load-acquire instruction where available (and yay! one more hook gone). 2015-06-04 Ramana Radhakrishnan <ramana.radhakrish...@arm.com> PR c++/66192 PR target/66200 * doc/tm.texi: Regenerate. * doc/tm.texi.in (TARGET_RELAXED_ORDERING): Delete. * target.def (TARGET_RELAXED_ORDERING): Likewise. * config/alpha/alpha.c (TARGET_RELAXED_ORDERING): Likewise. * config/ia64/ia64.c (TARGET_RELAXED_ORDERING): Likewise. * config/rs6000/rs6000.c (TARGET_RELAXED_ORDERING): Likewise. * config/sparc/linux.h (SPARC_RELAXED_ORDERING): Likewise. * config/sparc/linux64.h (SPARC_RELAXED_ORDERING): Likewise. * config/sparc/sparc.c (TARGET_RELAXED_ORDERING): Likewise. * config/sparc/sparc.h (SPARC_RELAXED_ORDERING): Likewise. * system.h (TARGET_RELAXED_ORDERING): Poison. 2015-06-04 Ramana Radhakrishnan <ramana.radhakrish...@arm.com> PR c++/66192 PR target/66200 * cp-tree.h (get_guard_cond): Adjust declaration * decl.c (expand_static_init): Use atomic load acquire and adjust call to get_guard_cond. * decl2.c (build_atomic_load_byte): New function. (get_guard_cond): Handle thread_safety. (one_static_initialization_or_destruction): Adjust call to get_guard_cond. Modified: branches/google/gcc-4_9/gcc/config/alpha/alpha.c branches/google/gcc-4_9/gcc/config/ia64/ia64.c branches/google/gcc-4_9/gcc/config/rs6000/rs6000.c branches/google/gcc-4_9/gcc/config/sparc/linux.h branches/google/gcc-4_9/gcc/config/sparc/linux64.h branches/google/gcc-4_9/gcc/config/sparc/sparc.c branches/google/gcc-4_9/gcc/config/sparc/sparc.h branches/google/gcc-4_9/gcc/cp/cp-tree.h branches/google/gcc-4_9/gcc/cp/decl.c branches/google/gcc-4_9/gcc/cp/decl2.c branches/google/gcc-4_9/gcc/doc/tm.texi branches/google/gcc-4_9/gcc/doc/tm.texi.in branches/google/gcc-4_9/gcc/system.h branches/google/gcc-4_9/gcc/target.def
