macro_rules! sel_reg(
($self_:ident.$method: ident::<$type: ident>($($args: expr),*)) => {
$self_.$method(RegType::<<$type as ToSimd>::RegFallback>::new(), $($args),*)
};
($method: ident::<$type: ident>($($args: expr),*)) => {
$method(RegType::<<$type as ToSimd>::RegFallback>::new(), $($args),*)
};
);