[Bug c++/121864] ICE with empty (or trivial) source, C++ modules, and -save-temps

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121864

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> The ICE is coming from this fatal error:
> 
>       if (fdeps_stream == deps_stream && fdeps_stream != stdout)
>         fatal_error (input_location, "%<-MF%> and %<-fdeps-file=%> cannot
> share an output file %s: %m",
>                      fdeps_file);

I am suspecting fdeps_file is null:
  gcc_checking_assert (str);