Hey Marek!

Thanks for having a look into this!

As far as I can tell, the bug occurs without the LLVM backend. I just realized,
that you have to set the environment variable "R600_LLVM", which I didn't.
Instead, I tried to activate the LLVM backend by adding the string "llvm" to
R600_DEBUG (yet, not in the run which created the traces). Furthermore,
R600_LLVM is not set by default on ArchLinux. So actually, I never tried the
LLVM backend.

If you'd like to have a trace using the LLVM backend, please let me know.