Can compiler generate std::move for a last use of lvalue automatically?

Question

A code like this is often seen in r-value references articles:

Dave Abrams: Move It With Rvalue References

void g(X);

void f()
{
    X b;
    g(b);          


        

Answer 1

(...) assuming a generic case the compiler does not know anything about how is move, copy or destruct implemented for the X class?

No, compilers are not allowed to do optimisations based on faith.

For clarity, this question is unrelated to copy elision: compilers may be allowed to elide a copy, but they cannot change copies to moves willy-nilly.