(In reply to smoki from comment #3)
>  I can reproduce this on Kabini with current proper mesa and llvm, but not
> with Tom's perf-Jan-08-2015 llvm + vgpr-spilling-Jan07-2014 mesa branches it
> works fine there.

Indeed, switching llvm to perf-Jan-08-2015 fixes the GPU faults.

For the record, with my Mesa installation from git master I do get
> Warning: Compiler emitted unknown config register: 0x286e8
in glretrace, but that doesn't seem to cause any visible breakage.

Should I leave the bug open until the fix hits LLVM trunk?