https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107555
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- Just the preprocessed .ii file for the one translation unit compile-rule.cxx is all that's needed. The bug reporting instructions don't say you have to minimise it (though that's certainly preferred) but they do say we need the preprocessed source.