I used the code found here. However, that does not update the title field until you open the post and hit Update button both via the back and front-end. I tried changing "save-post" hook with "edit_post", "publish_artist" and "wp_insert_post_data" but still get the same result. Below is the code I used upon using "wp_insert_post_data" hook.
add_filter( 'wp_insert_post_data' , 'modify_post_title' , '99', 2 ); // Grabs the inserted post data so you can modify it.
function modify_post_title( $data )
{
if($data['post_type'] == 'artist' && isset($_POST['artist_name'])) { // The custom field
$ArtistName = $_POST['artist_name'];
$data['post_title'] = $ArtistName ; //Updates the post title to your new title.
}
return $data; // Returns the modified data.
}