LLVM 4.0 Causes Slow Performance For RadeonSI?

Several times in the past few weeks I've heard Phoronix readers claim the LLVM 4.0 SVN code causes "slow performance" or has rendering issues. Yet it's gone on for weeks and I haven't seen such myself, so I decided to run some definitive tests at least for the OpenGL games most relevant to our benchmarking here...