Hello, > > The other thing we could try to do is put virtual variables in loop-closed- > > form, at least just before the vectorizer, and at least just for some > > loops. Does this sound reasonabale? (By the way, why don't we keep virtual > > variables in loop-closed-form?) > > We used to, nobody could come up with a good reason to keep doing it, so > we stopped.
there were couple of good reasons (consistency, faster updating after loop unrolling and loop header copying). However, LCSSA for virtual operands is memory expensive and this overweighted the advantages (in particular, slower updating during loop manipulations is compensated by everything else being faster). Zdenek
