Being worked on this past summer were improvements to the open-source ATI R300 driver when it comes to GLSL compiler optimizations. This work was done by Tom Stellar as part of Google's Summer of Code for student developers. While we reported on some of the R300 compiler improvements
back in June, there hasn't been too much more information to pass along, especially as the summer is now over. However, there is now a new branch by Stellar containing some additional optimizations.
Pushed to Tom Stellar's Mesa branch are R300 compiler optimization improvements for handling of flow control instructions in data-flow analysis, more aggressive use of pre-subtact operations, and more scheduler improvements. According to Tom, this has resulted in a 10% decrease on average in shader program size for his test cases.
Details and the Git tree are mentioned on his blog
. Now to hopefully see these optimizations merged into Mesa master for the Mesa 7.10 release...