PoCL is aiming at becoming an efficient open source (MIT-licensed) implementation of the OpenCL 1.2 (and soon OpenCL 2.0) standard. This release adds support for LLVM/Clang 3.3, employs inner loop parallelization in the kernel compiler, uses Vecmathlib for inlineable efficient math library implementations, contains plenty of bug fixes, and provides several new OpenCL API implementations.
Portable OpenCL (pocl) is a MIT-licensed open source implementation of the OpenCL standard which can be easily adapted for new targets and devices, both for homogeneous CPU and heterogenous GPUs/accelerators. pocl uses Clang as an OpenCL C frontend and LLVM for the kernel compiler implementation, and as a portability layer. Thus, if your desired target has an LLVM backend, it should be able to get OpenCL support easily by using pocl.