OpenMP support for LLVM/Clang has been talked about for a long time but only recently has it been acted upon. OpenMP is the multi-platform shared memory multi-processing API for Fortran/C/C++ that is very common for software developers to use for parallel programming.
Sanjoy Das is one of the developers that has been making progress in allowing LLVM to support OpenMP. In a new mailing list post, Sanjoy says, "I made some progress on implementing Hal's proposal for implementing OpenMP support in LLVM. The patch I've attached just barely compiles, but I'd like to get some input on the design early on to prevent grief later."
The code for the OpenMP LLVM support isn't currently within the mainline SVN repository but for the time being is being developed on GitHub.