(In reply to comment #7)
> Any chance you could try an LLVM 3.5 snapshot?
> 
> Also, if you could log in via ssh and grab dmesg after the problem occurs,
> that might be interesting.

I don't have a second machine of my own setup to try it from but I'll see what
I can do. For now, Xorg.0.log.old seems to better match up with the time of the
error, and shows a mumber of EQ overflow errors that aren't in Xorg.0.log.