std::experimental::element_aligned_tag, std::experimental::element_aligned
From cppreference.com
                    
                                        
                    < cpplrm; | experimentallrm; | simd
                    
                                                            
                    | Defined in header  <experimental/simd> | ||
| struct element_aligned_tag {}; inline constexpr element_aligned_tag element_aligned{}; | ||
This tag type indicates that the buffer of copy_from and copy_to is aligned to its element alignment.