Unified Parallel C (UPC) is an extension to C that's intended for high-performance computing across large-scale parallel machines. Unified Parallel C can handle both SMP/NUMA systems with a global address space along with distributed clusters. UPC extends ISO C99 with a parallel execution model, a shared address space, synchronization primities and a memory consistency model, explicit communication primitives, and memory management primitives.
The GNU Unified Parallel C implementation has existed as a branch of GCC for years, but now its developers are interested in merging it into trunk for GCC 4.8.
Gary Funck writes to the gcc-patches mailing list, "We have maintained the gupc (GNU Unified Parallel C) branch for a couple of years now, and would like to merge these changes into the GCC trunk. The purpose of this note is to ask for suggestions on the best way to proceed through the GUPC review and merge process."
GUPC complies with the UPC 1.2 specification, provides UPC collectives library support, Global Address Space Languages (GASP) support, Pthreads support, libupc for SMP systems, and the Berkeley UPC run-time can be built with GUPC as the compiler front-end. More information on the current GUPC implementation can be found at gcc.gnu.org. There's also more information at gccupc.org.
Besides this possible Unified Parallel C support merging, GCC 4.8 already has support for next-generation CPUs, its codebase has been converted from C to C++, improved diagnostics support, possible D language support, and much more.