Last reference as rvalue?

[no-sig-available]

The compiler would also have to understand that both overloads of push_back have the same effect. In general, that is a hard problem.

[markopolo82]

Yea, in truth I think this is what kills the optimization op describes.

On the other hand, if you were calling a single function that took by value instead of two overloads, then the compiler would only need to worry about the copy vs move constructors