A problem related to const rvalue

[<chmodexplorer at sina dot com>]

Hi,
I used gcc 4.8.0 to compile the piece of code:

#include <stdio.h>
#include <utility>

void f( const int & i )
{
        fprintf( stdout, "1 -> f( const int & i )-> %d\n", i );
}

void f( const int && i )
{
        fprintf( stdout, "2 -> f( const int && i )-> %d\n", i );
}

void f( int & i )
{
        fprintf( stdout, "3 -> f( int & i )-> %d\n", i );
}

void f( int && i )
{
        fprintf( stdout, "4 -> f( int && i )-> %d\n", i );
}

int f1() { return 0; }
int const f2() { return 0; }
int & f3( int & i ) { return i; }
int const & f4( const int & i ) { return i; }

int && f5( int && i ) { return std::move( i ); }
int const && f6( int const && i ) { return std::move( i ); }

int main()
{
        int i1 = 0;
        const int i2 = 0;

        int & i3 = i1;
        const int & i4 = i2;

        int && i5 = std::move( i1 );
        const int && i6 = std::move( i2 );


        f( i1 );
        f( i2 );
        f( i3 );
        f( i4 );
        f( i5 );
        f( i6 );

        f( f1() );
        f( f2() );
        f( f3( i3 ) );
        f( f4( i4 ) );
        f( f5( std::move( i1 ) ) );
        f( f6( std::move( i2 ) ) );

        return 0;
}

And the output of the program is:
3 -> f( int & i )-> 0
1 -> f( const int & i )-> 0
3 -> f( int & i )-> 0
1 -> f( const int & i )-> 0
3 -> f( int & i )-> 0
1 -> f( const int & i )-> 0
4 -> f( int && i )-> 0
4 -> f( int && i )-> 0
3 -> f( int & i )-> 0
1 -> f( const int & i )-> 0
4 -> f( int && i )-> 0
2 -> f( const int && i )-> 0

There are two lines of the strings: "4 -> f( int && i )-> 0". The first one is reasonable, but the second one makes me surprised. I guess that it should have been "2 -> f( const int && i )-> 0".

Is it a bug or by design? Who can answer the question for me?

Thanks very much!
cyril.