There was no real change in the Warsow gaming performance when switching out the AMD R600 compiler back-ends for graphics except for some very small changes here and there.
For low and high quality settings with the Xonotic game, the results were the same for the HD 4870/5830/6770 graphics cards. With the Radeon HD 4550 that is the lowest-end GPU tested, the LLVM back-end seemed to provide slightly more noticeable advantage.
When testing Xonotic with ultra quality settings, the R600 LLVM back-end was performing the best across all the Radeon GPUs tested, but by relatively small margins.
Overall, as far as Linux gamers and end-users are concerned, the R600 GPU LLVM back-end doesn't appear to yield any significant advantages in the OpenGL graphics performance but at least there are not any apparent regressions. The LLVM back-end is more pressing when it comes to allowing open-source OpenCL support and other capabilities. Stay tuned for more tests as the LLVM 3.3 release approaches in early June.