https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66090
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Since the pointer is wrapping to null, you need to use -fno-delete-null-pointer-checks to disable removing of checks of null pointers or rather it enables allowing pointers to wrap to become null. In C, once a pointer is non-null, it can't become null by adding a value to it. So GCC enables an optimization around that case (and fno-delete-null-pointer-checks disables that optimization). So no GCC bug, just wrongly assuming pointers can't become null pointers if they were not null pointers.