OpenCL SPIR code generation

Hi all,

I am trying to compile a openCL code to SPIR with LLVM/Clang-3.2.

I see there is no backend for SPIR( which makes sense as SPIR is variant of LLVM-IR). However this leads me clueless how to configure LLVM/Clang for SPIR and what is the command I shall use to generate SPIR code from cl code.