I just finished going through the API document adding missing content and updating stale information. While there are various aspects of GIMPLE that are not covered in the document, it is probably complete enough for converting/adding gimple code.
At the moment I'm wondering what would be the best way to host this documentation. Do we leave it on some web-based form (wiki or google docs)? Do we move it to the source tree as .texi files? I can see advantages to both approaches. Leaving it on the web, makes it easier to edit and evolve. Moving to the source tree makes it easier to version but harder to edit. The document is now linked off of the tuples wiki (http://gcc.gnu.org/wiki/tuples). The direct link is http://docs.google.com/Doc?id=dgfkmttj_107hcr98sg3 I would also appreciate feedback in terms of what is missing and what would be useful to add. Thanks. Diego.