Support for this common multi-processing API has long been desired for LLVM/Clang -- with GCC and other compilers having supported OpenMP for years now -- but only recently was there serious work on supporting OpenMP in LLVM/Clang for possible upstream inclusion.
Published today to the OpenMP mailing list thread was the latest OpenMP support enablement for Clang. The work allows for -fopenmp to be exposed and supported by Clang for utilizing this cross-platform multi-processing API used by programs like NPB and GraphicsMagick.
LLVM/Clang 3.2 will be released in December and its feature freeze is scheduled to happen in November. It's unknown at this point whether the Clang OpenMP support will settle by then and be merged or whether developers will still be waiting until next year to see this support.
On a semi-related note, there's LLVM Polly optimizer improvements in 3.2. I also published some LLVM/Clang 3.2 SVN performance benchmarks this morning.