wcloginout.php

/**
 * Login menu
 */

add_filter( 'wp_nav_menu_items', 'add_loginout_link', 10, 2 );
function add_loginout_link( $items, $args ) {
    if (is_user_logged_in() && $args->theme_location == 'primary') {
        $items .= '<li><a href="'. wp_logout_url( get_permalink( woocommerce_get_page_id( 'myaccount' ) ) ) .'">Log Out</a></li>';
    }
    elseif (!is_user_logged_in() && $args->theme_location == 'primary') {
        $items .= '<li><a href="' . get_permalink( woocommerce_get_page_id( 'myaccount' ) ) . '">Log In/Register</a></li>';
    }
    return $items;
}