Patch for PR libgomp/37938, IA64 specific.

[Jakub Jelinek]

On Fri, Nov 07, 2008 at 11:33:26AM -0800, H.J. Lu wrote:
> I am testing this patch. There is no need for memory barrier with acq semantics.

Isn't acquire semantics of cmpxchg.acq weaker than fence semantics that
__sync_* builtins other than __sync_lock_{test_and_set,release} are supposed
to have?  E.g. http://refspecs.freestandards.org/elf/IA64-SysV-psABI.pdf
documents __sync_{bool,val}_compare_and_swap as Full barrier.  I think
in libgomp, glibc and many other places __sync_{bool,val}_compare_and_swap
is used in places where release semantics or fence semantics is needed.

	Jakub