OpenArena, one of the most common and easiest tests of the Mesa graphics stack, regresses with the current 7.12-devel state. Mesa 7.11.2 Git is running at 85 FPS for this hardware/software configuration, but right now on Mesa Git master it has fallen to 76 FPS, a drop of more than 10%. Mesa 7.11 itself is also slower than Mesa 7.9 and 7.10.
World of Padman is based on the ioquake3 engine like OpenArena, and here its performance has fallen with this forthcoming Mesa release. The World of Padman frame-rate at 1920 x 1080 has dropped from 90 FPS to 78 FPS, which is not a big deal for a high-end R500 ASIC but for lower-end R500s or the R300/R400 hardware it could potentially make the game no longer playable.
The frame-rate of Urban Terror, the third ioquake3 game, has also fallen sharply. In fact, with this game the change in performance is the worst: going from 84 FPS to 49 FPS. Ouch.