function login_form_olustur() {
    if( is_user_logged_in() )
        return 'Giriş Yaptınız.';

    $args = array(
        'echo'           => false,
        'remember'       => true,
        'redirect'       => ( is_ssl() ? 'https://' : 'http://' ) . $_SERVER[ 'HTTP_HOST' ] . $_SERVER[ 'REQUEST_URI' ],
        'form_id'        => 'loginform',
        'id_username'    => 'user_login',
        'id_password'    => 'user_pass',
        'id_remember'    => 'rememberme',
        'id_submit'      => 'wp-submit',
        'label_username' => __( 'Username or Email Address' ),
        'label_password' => __( 'Password' ),
        'label_remember' => __( 'Remember Me' ),
        'label_log_in'   => __( 'Log In' ),
        'value_username' => '',
    );

    return wp_login_form( $args );
}

add_action( 'init', 'login_form_kısakod' );

function login_form_kısakod() {
    add_shortcode( 'giris-yap', 'login_form_olustur' );
}