Class strided_ptr

less_slow.cpp:2815–2859

 */
template <typename value_type_>
class strided_ptr {
    std::byte *data_;
    std::size_t stride_;

  public:
    using value_type = value_type_;
    using pointer = value_type_ *;
    using reference = value_type_ &;
    using difference_type = std::ptrdiff_t;
    using iterator_category = std::random_access_iterator_tag;

    strided_ptr(std::byte *data, std::size_t stride_bytes) : data_(data), stride_(stride_bytes) {
        assert(data_ && "Pointer must not be null, as NULL arithmetic is undefined");
    }
#if defined(__cpp_lib_assume_aligned) // Not available in Apple Clang
    reference operator*() const noexcept {
        return *std::launder(std::assume_aligned<1>(reinterpret_cast<pointer>(data_)));
    }
    reference operator[](difference_type i) const noexcept {
        return *std::launder(std::assume_aligned<1>(reinterpret_cast<pointer>(data_ + i * stride_)));
    }
#else
    reference operator*() const noexcept { return *reinterpret_cast<pointer>(data_); }
    reference operator[](difference_type i) const noexcept { return *reinterpret_cast<pointer>(data_ + i * stride_); }
#endif // defined(__cpp_lib_assume_aligned)

    // clang-format off
    pointer operator->() const noexcept { return &operator*(); }
    strided_ptr &operator++() noexcept { data_ += stride_; return *this; }
    strided_ptr operator++(int) noexcept { strided_ptr temp = *this; ++(*this); return temp; }
    strided_ptr &operator--() noexcept { data_ -= stride_; return *this; }
    strided_ptr operator--(int) noexcept { strided_ptr temp = *this; --(*this); return temp; }
    strided_ptr &operator+=(difference_type offset) noexcept { data_ += offset * stride_; return *this; }
    strided_ptr &operator-=(difference_type offset) noexcept { data_ -= offset * stride_; return *this; }
    strided_ptr operator+(difference_type offset) const noexcept { strided_ptr temp = *this; return temp += offset; }
    strided_ptr operator-(difference_type offset) const noexcept { strided_ptr temp = *this; return temp -= offset; }
    friend difference_type operator-(strided_ptr const &a, strided_ptr const &b) noexcept { assert(a.stride_ == b.stride_); return (a.data_ - b.data_) / static_cast<difference_type>(a.stride_); }
    friend bool operator==(strided_ptr const &a, strided_ptr const &b) noexcept { return a.data_ == b.data_; }
    friend bool operator<(strided_ptr const &a, strided_ptr const &b) noexcept { return a.data_ < b.data_; }
    friend bool operator!=(strided_ptr const &a, strided_ptr const &b) noexcept { return !(a == b); }
    friend bool operator>(strided_ptr const &a, strided_ptr const &b) noexcept { return b < a; }
    friend bool operator<=(strided_ptr const &a, strided_ptr const &b) noexcept { return !(b < a); }
    friend bool operator>=(strided_ptr const &a, strided_ptr const &b) noexcept { return !(a < b); }
    // clang-format on
};

#if defined(__aarch64__)
/**