friend constexpr mask_type operator==(const basic_vec& lhs, const basic_vec& rhs) noexcept;
friend constexpr mask_type operator!=(const basic_vec& lhs, const basic_vec& rhs) noexcept;
friend constexpr mask_type operator>=(const basic_vec& lhs, const basic_vec& rhs) noexcept;
friend constexpr mask_type operator<=(const basic_vec& lhs, const basic_vec& rhs) noexcept;
friend constexpr mask_type operator>(const basic_vec& lhs, const basic_vec& rhs) noexcept;
friend constexpr mask_type operator<(const basic_vec& lhs, const basic_vec& rhs) noexcept;