https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71336
--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #6) > Sorry this one is more correct > Something like (very much pesdu code): > (simplify > (cond (eq (bit_and@0 @1 int_pow2p@2) integer_zerop) INTEGET_CST@3 > INTEGER_CST@4) > (switch > (if (@3 u> @4 && exact_pow2(@3 - @4)) > (convert (plus (mult (rshift @0:typeu @2) (minus @3:typeu @4:typeu)) > @4:typeu))) > (if (@4 u> @3 && exact_pow2(@4 - @3)) > (convert (minus (mult (rshift @0:typeu @2) (minus @4:typeu @3:typeu)) > @3:typeu)) > )) > > The mult could be changed to lshift to be more correct. I should note, the above is now only possible because of the recent changes I did to phi-opt. You no longer need to open code anything in phi-opt for things like this bug, just add them to match.pd and be done with it :).
