Bernd Schmidt <bernds_...@t-online.de> writes: > On 10/03/11 19:23, Richard Sandiford wrote: >> Bernd Schmidt <bernds_...@t-online.de> writes: >>>> Reason for asking is that (AIUI) SMS used to use stronger memory >>>> disambiguation, but had to pull back to something more conservative >>>> for similar reasons. >>> >>> Pointers? All I could find is a thread where rth seems to be of the same >>> opinion as me: >>> >>> http://gcc.gnu.org/ml/gcc/2004-09/msg01648.html >> >> I was thinking of: >> >> http://gcc.gnu.org/ml/gcc-patches/2010-08/msg00294.html > > What I see in this thread is suggestions that people use > {true,anti,output}_dependence, which are exactly the ones used by > sched-deps. We know that using these is (or rather, must be) safe > because RTL loop unrolling followed by scheduling works.
But what I'm trying to say is that you're not just doing loop unrolling followed by scheduling. You're doing loop unrolling, followed by scheduling, followed by an overlapping of the unrolled loop iterations. It just felt strange that the overlapping was being done without any additional alias analysis. But I admit it's a theorotical objection at best, and I'm certainly not going to be able to come with an example, so never mind me :-) Richard
