[Bug sanitizer/119140] Diagnose with -fsanitize={bounds,bounds-strict} taking address of one past last element if it is obviously dereferenced in the same function

[siddhesh at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119140

--- Comment #1 from Siddhesh Poyarekar <siddhesh at gcc dot gnu.org> ---
How about emitting .ACCESS_WITH_SIZE for p (or in case of foo, the return
value), i.e.

const __SIZE_TYPE__ sz = sizeof (b) - i;
.ACCESS_WITH_SIZE(&p, &sz, ...)

which should survive optimizations and in a later ubsan pass, look at
.UBSAN_BOUNDS lhs to see if it has any .ACCESS_WITH_SIZE calls and then adjust
the size accordingly?