[Bug libstdc++/77686] [6/7 Regression] wrong code on arm-linux-gnueabi and arm-linux-gnueabihf

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77686

--- Comment #16 from Jonathan Wakely <redi at gcc dot gnu.org> ---
For C++ 12.8 [class.copy] says:

-16- The implicitly-defined copy/move constructor for a union X copies the
object representation (3.9) of X.


and 

-29- The implicitly-defined copy assignment operator for a union X copies the
object representation (3.9) of X.

so it is a bytewise copy for PODs.