In the 1980s movie 'Girls Just Want to Have Fun' does Sarah Jessica Parker perform the movie's memorable gymnastics, or is a stunt double used?

I have not seen the movie myself. IF the "memorable gymnastics" can somehow be equated with the elaborate dance sequences that I have read about. I would say that a stunt double was involved.

Here are some excerpts from the reputable IMDB movie database:

Revealing mistakes: Obvious stand-ins for Janey and Jeff during the dance auditions.

Revealing mistakes: During the first audition, when Lynn gets stepped on and thrown on the floor by her dance partner, behind them you can see Jeff's and Janey's dance doubles.

http://www.imdb.com/title/tt0089208/goofs

I can't find a totally reputable source for this, but the source I did find says that a stunt double was used in the gymnastics scenes, but not in the dance scenes.

http://www.youtube.com/watch?v=KgirOQ-Ll1M