https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60519
--- Comment #2 from François Dumont <fdumont at gcc dot gnu.org> --- Created attachment 35305 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35305&action=edit Strict weak ordering debug check patch On my side here what I had plan to do. This patch rely on additional feature in the _Formatter type to pass a type or iterator value_type to point the user to the invalid operator or functor. It also do not perform the check if the comparator is not able to handle it. So yes it doubles the number of comparisons which is definitely a performance hint but your patch on the other hand expect to detect an implementation issue on only 1 use case so it can miss many kind of wrong implementation on special instances.
