There is also spdiff. A tool that generates semantic patches based previous on changes. Useful if
library api changes or some internal kernel api does. Also as noted in the article, just helpful for
finding better solutions.
Spdiff was presented here at diku (www.diku.dk) at a phd. defence i went to a few weeks ago.
Spdiff was stated as quite hard to use though (even for cochinelle folks), but it's also very young
so improvements are likely possible ;).