[Bug c/67999] Wrong optimization of pointer comparisons

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67999

--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC assumes objects will not wrap around zero only (well, it assumes objects
cannot live at address zero but it also assumes that the
pointer-to-one-element-after isn't zero or wraps around zero).