https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94359
--- Comment #2 from Iain Sandoe <iains at gcc dot gnu.org> --- it is not mandatory (for C++20 compliance) that the implementation provides symmetric transfer - so it could be switched off - or XFAILed. However, users state that an impl. that can't do the symmetric transfers is not useful in a number of important applications.
