https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106542
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- The code is undefined as the subtraction is done in the int type. You either need to use -fwrapv or cast to an unsigned type before doing the subtraction.