On June 13, 2021 4:03:16 AM GMT+02:00, Andrew Pinski <pins...@gmail.com> wrote: >On Sat, Jun 12, 2021 at 5:21 PM Andrew Pinski <pins...@gmail.com> >wrote: >> >> On Sat, Jun 12, 2021 at 4:54 PM Andrew Pinski <pins...@gmail.com> >wrote: >> > >> > Hi all, >> > While moving the simple A CMP 0 ? A : -A patterns from >> > fold_cond_expr_with_comparison to match, I ran into an issue where >> > using cond directly in the patterns work while "for cnd (cond >> > vec_cond)" don't work. >> > It looks like in the first case we are able to correctly handle the >> > cond first operand being a comparison while with the for loop we >are >> > not. >> > >> > That is the following additional pattern works: >> > /* A == 0? A : -A same as -A */ >> > (simplify >> > (cond (eq @0 zerop) @0 (negate@1 @0)) >> > (if (!HONOR_SIGNED_ZEROS (element_mode (type))) >> > @1)) >> > (simplify >> > (cond (eq @0 zerop) zerop (negate@1 @0)) >> > (if (!HONOR_SIGNED_ZEROS (element_mode (type))) >> > @1))) >> > >> > While this one does not work: >> > (for cnd (cond vec_cond) >> > /* A == 0? A : -A same as -A */ >> > (simplify >> > (cnd (eq @0 zerop) @0 (negate@1 @0)) >> > (if (!HONOR_SIGNED_ZEROS (element_mode (type))) >> > @1)) >> > (simplify >> > (cnd (eq @0 zerop) zerop (negate@1 @0)) >> > (if (!HONOR_SIGNED_ZEROS (element_mode (type))) >> > @1))) >> > >> > ---- CUT --- >> > I will try to debug genmatch some but I wanted to get this email >out >> > to record what will need to be fixed to continue the movement of >> > phiopt over to match. >> >> So the problem is we lower for loops first and then cond. Though >> swapping the order in genmatch's lower function causes invalid C++ >> code to be generated :(. >> Still trying to figure out why though. > >I figured out why; lower_cond does not copy for_subst_vec for the new >simplifier. Fixing that allows the switching of the order of the two >lower functions which is needed in this case. >I will submit the patch for this when I submit the patch set for >converting the simple "A CMP 0 ? A : - A" of >fold_cond_expr_with_comparison.
Hmm, it was done so on purpose because cond lowering does not see what is a cond w/o for lowered. So why does it not work with lowered for? I'll have a look next week. Richard. >Thanks, >Andrew Pinski > >> >> Thanks, >> Andrew >> >> > >> > Thanks, >> > Andrew Pinski
