https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110304
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
__builtin_adcb, __builtin_adcs and __builtin_subcb, __builtin_subcs weren't
added intentionally, I doubt they are widely used in practice. And
__builtin_u{add,sub}{,l,ll}_overflow isn't defined for them either. One can
always use a pair of __builtin_{add,sub}_overflow if one really needs the
8-bit/16-bit ones.
As for code generation on mips, loongarch etc., it is up to the target
maintainers to make sure good code is generated out of __builtin_*_overflow for
the common cases (all same types for them), or they even have now the option to
implement the uaddc5/usubc5 optabs if it helps with the code generation for
these.
