[Bug sanitizer/90347] [UBSAN] __attribute__((weak))__ results in "declared weak after being used" error

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90347

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
ubsan_maybe_instrument_reference_or_call sets
flag_delete_null_pointer_checks = 1;
and then we call tree_single_nonzero_warnv_p -> maybe_nonzero_address ->
symtab_node::nonzero_address

1979   if (!DECL_WEAK (decl)
1980       && flag_delete_null_pointer_checks)
1981     {
1982       refuse_visibility_changes = true;
1983       return true;
1984     }