We have known for months that GUPC wants to be part of GCC 4.8, but it has yet to be merged while GCC 4.8 should be out in about H1'2013.
Gary Funck on Monday sent in another email with "request for comments" about merging GNU Unified Parallel C to GCC trunk for the 4.8 release. "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. It is our goal to integrate the GUPC changes into the GCC 4.8 trunk, in order to provide a UPC (Unified Parallel C) capability in the subsequent GCC 4.8 release."
GUPC is a Unified Parallel C (UPC) implementation for GCC with compilation and execution support. Unified Parallel C is a C programming language extension that targets high-performance computing on parallel machines by introducing an explicitly parallel execution model, shared address space, synchronization primitives, a memory consistency model, explicit communication primitives, and memory management primitives.
GUPC has been independently maintained for years, but now it wants to be part of the official GNU Compiler Collection.
More information on GUPC can be found from its GNU.org project page.