On Wed, Apr 8, 2009 at 5:19 PM, Richard Guenther <rguent...@suse.de> wrote: >> - We ought to be able to prove finitarity of simple loops so we can >> DCE more early and won't rely on full loop unrolling to get rid of >> empty loops originally initializing dead arrays. > > I wonder if CD-DCE should not catch this, but I see that for > > for(i=0;i<4;++i) > ; > > we do > > Marking useful stmt: if (i_1 <= 3) > > which is already a problem if we want to DCE the loop. Can we > mark the controlling predicate necessary somehow only if we > mark a stmt necessary in the BBs it controls?
This is just what CD-DCE is supposed to do. If it doesn't work, then CD-DCE is broken. Ciao! Steven
