[Bug lto/65536] LTO line number information garbled

[hubicka at ucw dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65536

--- Comment #51 from Jan Hubicka <hubicka at ucw dot cz> ---
> 
> Contrary to what I said before, I think now that it really makes sense for
> line-maps to return UNKNOWN_LOCATION rather than the location of something else
> when overflow occurs, but then LTO has to detect this case and decide what to
> do.

This would affect not only LTO code - all C++ FE's can face an overflow in
exterme cases
and becuase we special case everyting <=BUILTINS_LOCATION perhaps we really can
just
add extra special value WRONG_LOCATION that would be used to denote this?

Honza