https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82853
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Component|target |middle-end --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- For your code aarch64 produces: mod3: mov w1, 43691 movk w1, 0xaaaa, lsl 16 umull x1, w0, w1 lsr x1, x1, 32 lsr w1, w1, 1 add w1, w1, w1, lsl 1 cmp w0, w1 cset w0, eq ret Oh you mean not to produce a%3 followed by == part :). Anyways this code should go into the middle-end expanders and not be part of match.pd.