https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55534
--- Comment #11 from Tobias Burnus <burnus at gcc dot gnu.org> ---
The problem is an ordering problem.
Namely:
* toplev.c calls:
lang_hooks.init_options (save_decoded_options_count, save_decoded_options);
which in turn is:
gfc_init_options ( ....
{
...
SET_OPTION_IF_UNSET (&global_options, &global_options_set,
cpp_warn_missing_include_dirs, 1);
...
/* Initialize cpp-related options. */
gfc_cpp_init_options (decoded_options_count, decoded_options);
...
}
Thus, cpp_warn_missing_include_dirs is enabled.
Now:
decode_options (&global_options, &global_options_set, ...
is run, which calls:
read_cmdline_options (opts, opts_set, ...
→ read_cmdline_option
→ handle_option
→ gfc_handle_option
→ gfc_add_include_path
→ gfc_warning_now
and only afterwards decode_options invokes:
set_option (...)
which then sets:
global_options_set->x_... = 1
and
global_options->x_... = commandline option.
and disables the already shown warning.
