On 2013-09-20 16:47:24 +0200, Andres Freund wrote: > I think we should go through the various implementations and make sure > they are actual compiler barriers and then change the documented policy.
From a quick look * S_UNLOCK for PPC isn't a compiler barrier * S_UNLOCK for MIPS isn't a compiler barrier * I don't know enough about unixware (do we still support that as a platform even) to judge * True64 Alpha I have no clue about * PA-RISCs tas() might not be a compiler barrier for !GCC * PA-RISCs S_UNLOCK might not be a compiler barrier * HP-UX !GCC might not * IRIX 5 seems to be a compiler barrier * SINIX - I don't care * AIX PPC - compiler barrier * Sun - TAS is implemented in external assembly, normal function call, compiler barrier * Win(32|64) - compiler barrier * Generic S_UNLOCK *NOT* necessarily a compiler barrier.