With that, the TGSI the driver sees is already a lot better optimized than before, but a few problems still remain: The per-LDS address calculation is still done, instruction groups are not filled if a TGSI instruction does not use all four slots, and if the shader does not allow for SB to be used, then this is the code that is executed by the hardware. Since the TGSI back-end doesn't support fp64 here, piglit was once run on NIR skipping the fp64 tests to directly compare to TGSI, and once including the fp64 tests: In addition, even though SB is usually capable of improving the code produced by the NIR back-end, the performance win is generally smaller then when optimizing the code that was created by the TGSI back-end.