https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115065
--- Comment #1 from Georg-Johann Lay <gjl at gcc dot gnu.org> --- IIUC, this is just about the timing of a branch, which in the general != 0 is currently taken (takes 2 ticks), but it's better to only take it in the non-common (= 0) case? So that the common case falls through and thus takes 1 cycle less.
