[Bug middle-end/123801] [12/13/14/15/16 Regression] Wstringop-overflow false positive since r12-4240

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123801

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Before IPA we try to preserve the exact access path for __builtin_object_size
reasons (except for bugs) but after IPA it is really solely about equivalent
addresses.
There were talks in other PRs about VN changing the access path on ADDR_EXPRs
to something that could to some extent work in both, whether it is just MEM_REF
of the base with offset or e.g. in this case to the anon union as something
common between those, but nothing has been implemented and the question is how
hard would it be to do so.