https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113734
--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Tamar Christina from comment #10) > (In reply to Richard Biener from comment #9) > > Another bug in the dependence checking code is > > > > if (dr_may_alias_p (dr_ref, dr_read, loop_nest)) > > > > which will end up using TBAA - dr_may_alias_p doesn't think you are ever > > going to move stores down across loads. To verify if that's possible > > you need to use > > > > if (dr_may_alias_p (dr_read, dr_ref, loop_nest)) > > > > instead. > > > > Note there's still my very original review consideration that you move > > stmts out-of-order but the main dependence checking the vectorizer does > > assumes the stores and loads appear in their original order. I'm not > > sure whether with the above we prove this doesn't matter. > > But in the original review I had it that way and you said: > > > + for (auto dr_read : bases) > > + if (dr_may_alias_p (dr_read, dr_ref, loop_nest)) > > I think you need to swap dr_read and dr_ref operands, since you > are walking stmts backwards and thus all reads from 'bases' are > after the write. > > so I'm somewhat confused.. I was confused.
