There Were Many Changes During The Making Of The Film
Between the first and final drafts of the film, there were numerous major changes in the script that completely changed the direction of the movie. The original screenplay was written by Danny Rubin who wrote the role of Phil for someone like Kevin Kline.
His version had the audience kept in the dark about the time loop, something they would have to figure out themselves. Phil then kills himself yet wakes up to the same morning once again. Furthermore, in the original ending, Rita admitted that she was stuck in a time loop as well.