[Bug lto/78529] [7 Regression] gcc.c-torture/execute/builtins/strcat-chk.c failed with lto/O2

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78529

--- Comment #29 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
I think the official answer for LTOing symbols implementing runtime (i.e. those
that can be introduced by middle-end) is "don't do that". We may support LTOing
them with an explicit attribute "used" on them or, if we get really into LTOing
runtime libraries, somehow auto generating used attributes by having some
central way of saying if symbol is implementing runtime or not. We don't have
this and we have many different runtime calls (libgcc, decnumber, standard
library symbols like printf->putc translation and many more).