In the paragraph #15 of section 6.9.2.2 Data races of the C++20 Standard  there is written
 
«15 If an operation A that modifies an atomic object M happens before an operation B that modifies M, then A shall be earlier than B in the modification order of M.»
 
Is not it just a tautology?
 
With best regards
(Vlad from Moscow)
You can meet me at http://cpp.forum24.ru/ or www.stackoverflow.com or http://ru.stackoverflow.com