I would highly, strongly recommend that you NOT do that. I am almost certain that you will pop another log-in controller onto the view controller stack. You will then have 4 view controllers in the stack when you only want one. Please look at this post on unwind segues or use popViewController.
http://stackoverflow.com/questions/12561735/what-are-unwind-segues-for-and-how-do-you-use-them