While new LLVM/Clang releases come every six months, traditionally the LLVM project doesn't see point, bug-fix releases even though it's been talked up many times in the past. In Marc, Tom Stellard at AMD began gaining support for going ahead with an LLVM 3.4.1 release mainly so they could ship minor fixes/improvements for their GPU LLVM back-end but to also benefit other back-end targets and the LLVM code-base as a whole. LLVM 3.4.1 was in testing since last month and finally today it's officially available.
Among the improvements to find with LLVM 3.4.1 are a var args fix for x86, geometry shaders support for the R600 AMD back-end, C++11 fixes, and fixes to other LLVM back-ends -- including the targets for AArch64, ARM, PowerPC, R600, and x86.
Besides needing the LLVM 3.4.1+ release to have working OpenGL Geometry Shaders support for the RadeonSI Gallium3D driver, you also need Mesa Git, particularly today's commit that will allow OpenGL Geometry Shaders to be used with exposing the OpenGL 3.3 GLSL level.
More information on the LLVM 3.4.1 point release can be found via the mailing list release announcement.