An Important Radeon R600 Change In LLVM 3.4

While LLVM 3.3 hasn't even been released yet, there's already an important change found in LLVM 3.4 for Radeon R600 GPU users.

The Radeon R600 LLVM back-end, which is used by the Radeon Gallium3D driver for Compute/OpenCL support and optionally for shader compilation, was merged for LLVM 3.3. While it was merged for LLVM 3.3 and has matured quite a bit, it remains an "experimental" back-end for the imminent LLVM release.

With LLVM 3.4, the R600 back-end is no longer deemed experimental. The R600 back-end in the LLVM 3.3 release requires the --enable-experimental-targets=R600 compiler switch, but per early LLVM 3.4 notes, "The R600 backend is not marked experimental anymore and is built by default."

Beyond this fundamental change, the R600 back-end in LLVM 3.4 has already picked up numerous Radeon improvements in the weeks since LLVM 3.3 was branched. For end-users, unfortunately the LLVM 3.4 release will likely not be here until around year's end.