On 09/09/2011 10:17 AM, Jakub Jelinek wrote:
> Is the above analysis correct? Or should the users put explicit
> compiler barriers?
I'd say they should be optimization barriers too (and at the tree level
they I think work that way, being represented as function calls), so if
they don't act as memory barriers in RTL, the *.md patterns should be
fixed. The only exception should be IMHO the __SYNC_MEM_RELAXED
variants - if the CPU can reorder memory accesses across them at will,
why shouldn't the compiler be able to do the same as well?
Agreed, so we have a bug in all released versions of GCC. :(
Paolo
