AMD's R600 GPU LLVM Back-End To Be Renamed

AMD's "R600" LLVM back-end is likely to be renamed for LLVM 3.6.

Tom Stellard of AMD is seeking the approval of other LLVM developers to rename the R600 back-end to something more generic like "AMDGPU" instead. The R600 back-end was originally developed for AMD's R600 class hardware with support through the HD 6000 "Northern Islands" graphics cards, just as is the case for the R600 Gallium3D driver. However, while AMD developed the RadeonSI Gallium3D driver for the HD 7000 series graphics processors and newer, the existing R600 LLVM back-end has been extended to support all newer AMD GPUs up through the latest Rx 200 series graphics cards. As a result, the "R600" name is rather irrelevant and no longer meaningful.

Rather than renaming it to something like "R600ThorughGCNGPUs", Stellard is looking to rename the compute back-end to just AMDGPU. Stellard explained the initial name reasoning:

The reason that the backend was originally called R600 and not AMDGPU is because there was concern that the name AMDGPU was too generic, and it would be confusing if AMD came out with a new architecture which required a new backend. In this happened, we would have an AMDGPU backend, which didn't support all AMD GPUs.

We actually have an example of this situation today with ARM and ARM64, and this doesn't seem to have caused too much confusion. Plus, I would much prefer people try a backend thinking something was supported and have it not work than people assuming the backend didn't work for their GPU and ignoring it completely.

Tom's proposal has went through with the approval of upstream. Following the LLVM 3.5 release later this month, R600 should be renamed to AMDGPU. For a release or two, the "R600" name will still be supported by the build systems for easing the transition while there should be no functional difference with the new AMDGPU name.