http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51766
--- Comment #8 from David Edelsohn <dje at gcc dot gnu.org> 2012-01-10 18:08:23 UTC --- For the way that programmers use __sync_* builtins, release or acquire-release semantics are sufficient. As we see in libstdc++, release semantics are overly strict when incrementing the reference, as opposed to destroying an object. Again, there is no cost to Intel specifying sequential consistency as opposed to a slightly weaker memory model. Intel chose a memory model that matched and benefited their architecture. IBM should have the freedom to choose memory models that benefit its architectures.
