rewrite rules "/cpt-label/category/slug/"

gistfile1.php

/*
don't forget to flush permalinks
/cpt-label/category/slug/
*/
function os_part_tags() {
  add_rewrite_rule("^cpt-label/([^/]+)/page/([^/]+)/?",'index.php?post_type=cpt-label&cat=$matches[1]&paged=$matches[2]','top');
	add_rewrite_rule("^cpt-label/([^/]+)/([^/]+)/?",'index.php?cpt-label=$matches[2]','top');
	add_rewrite_rule("^cpt-label/?",'index.php?post_type=cpt-label','top');

}
add_action('init','os_part_tags');


function os_adds_link( $post_link, $id = 0 ) {

	$post = get_post($id);

	if ( is_wp_error($post) || 'cpt-label' != $post->post_type || empty($post->post_name) )
		return $post_link;

	// Get the model:
	$terms = get_the_terms($post->ID, 'category');

	if( is_wp_error($terms) || !$terms ) {
		$genre = 'uncategorised';
	}
	else {
		$genre_obj = array_pop($terms);
		$genre = $genre_obj->slug;
	}

	return home_url(user_trailingslashit( "cpt-label/$genre/$post->post_name" ));
}
add_filter( 'post_type_link', 'os_adds_link' , 10, 2 );