[Bug tree-optimization/94335] False positive -Wstringop-overflow warning with -O2

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94335

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
You should be using (intptr_t)t - (intptr_t)this when computing the relative
pointer, not sure if that makes a difference but pointer difference between
pointers to different objects invokes undefined behavior.