https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94902
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Or there are possible target ways, e.g. asm ("frame") would be rejected if that
register isn't in accessible_reg_set or operand_reg_set. Now, I haven't
investigated if it doesn't have to be in both sets for what the register is
used internally.
