https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107703
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> --- aarch64 isn't affected (yet), the __bf16 arithmetics support patch has just been posted but not reviewed. So, on arm and aarch64 __bf16 is a store only type one can't convert to/from nor use in unary/binary operations.
