... BTW, I wonder why you did not add pg_compiler_barrier_impl()
to our other use of __atomic_thread_fence:
#if !defined(pg_memory_barrier_impl)
# if defined(HAVE_GCC__ATOMIC_INT32_CAS)
# define pg_memory_barrier_impl()
__atomic_thread_fence(__ATOMIC_SEQ_CST)
# elif defined(__GNUC__)
# define pg_memory_barrier_impl() __sync_synchronize()
# endif
#endif /* !defined(pg_memory_barrier_impl) */
If the problem is that Clang doesn't treat __atomic_thread_fence
as a compiler barrier, why is this usage safer than the other two?
regards, tom lane
