https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99992
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- So perhaps copy and tweak massage_constexpr_body and constexpr_fn_retval such that it doesn't break_out_target_exprs but just return non-NULL/error_mark_node on RETURN_EXPR and does something sensible for DECL_CONSTRUCTORs (or initially handles only non-ctors?)?
