https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95060
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I see the needed simplifiers in match.pd: (simplify (negate (fmas@3 @0 @1 @2)) (if (single_use (@3)) (IFN_FNMS @0 @1 @2)))) but perhaps the problem is that there is no forwprop after widening_mul that would perform that optimization? So, shall widening_mul itself if it matches some FMA check if the result of IFN_{FMA,FMS,FNMA,FNMS} it created isn't negation and if yes, try to gimple_fold it?