On Mon, Nov 17, 2014 at 12:36 PM, Andi Kleen <a...@firstfloor.org> wrote: > "H.J. Lu" <hjl.to...@gmail.com> writes: > >> On Wed, Oct 29, 2014 at 11:07 PM, Andi Kleen <a...@linux.intel.com> wrote: >>>> >>>> Hmm, can't the insns themselves properly clobber/use memory? >>> >>> The transactions don't really use the memory. They just guard it, >>> like a lock. >>> >>> So the intrinsic doesn't know what memory is used inside the transaction, >>> but the accesses still cannot be moved out. >>> >>> I think a barrier is the only sensible option. >>> >>>> I suppose they are UNSPEC_VOLATILE anyway, right? >>> >>> That doesn't have any barrier semantics by itself, does it? >>> >> >> Do you have a testcase to show it makes a difference? > > It fixed customer code. I currently don't have a separate > test case. >
If you can extract a small testcase, it will be much easier to review. -- H.J.
