[Bug c/85365] -Wrestrict false positives with -fsanitize=undefined

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85365

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
We warn because we see
strcpy (0B, 0B);
created by jump threading (in a BB that is not reachable).