https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63303
--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> --- To support the standards definition of p1 - p2 we'd need a POINTER_DIFF_EXPR that also embeds the exact division by the array element size. Btw, while C and C++ share pointer_int_sum they have differing implementations for computing pointer differences. The safe variant would be indeed to compute the pointer difference using an unsigned type and I can't see what optimizations we lose when doing that. Note that you'd still need to convert the result to a signed type before doing the exact division by the element size.
