Last month in Cambridge was the 2014 GNU Tools Cauldron where GCC as a JIT compiler and other interesting topics were discussed by developers. One of the topics discussed was surrounding better collaboration between GCC and LLVM developers.
While in my earlier 2014 GNU Tools Cauldron coverage I commented on the session about GCC+LLVM collaboration, after the past Phoronix article on the event some additional information was published. The purpose of the GCC and LLVM/Clang compiler teams collaborating is to reach common defaults between compilers, avoid confusion with architecture flags and other compiler switches, and make other improvements to better the interoperability between the compilers to make a better end-user/developer experience. The focus isn't on merging GCC+LLVM, debating licensing differences, fighting over who as the faster compiler, or other such heated topics.