AMD's new Boltzmann initiative includes an LLVM-based compiler which has been posted online. I'm not sure what are the plans around an OpenCL fronted, but the backend should be there, so I think an OpenCL support in LLVM for AMD GPUs could be a realistic goal.

http://gpuopen.com/compute-product/hcc-heterogeneous-compute... https://github.com/RadeonOpenCompute/hcc