https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114657
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org, | |jsm28 at gcc dot gnu.org --- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I believe Joseph said this isn't well specified in the C standard, see https://gcc.gnu.org/pipermail/gcc-patches/2023-July/625765.html If you use something like + 0uwb it should be the type after the integral promotions and so what the standard specifies for integral promotions of the _BitInt bit-fields.