https://bugs.freedesktop.org/show_bug.cgi?id=65873
--- Comment #3 from Tom Stellard tstellar@gmail.com --- These patches should fix the issue:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20130617/178156....
The first patch is unrelated to the bug, but it is required in order to prevent the test case in the second patch from crashing on Cayman. I've tested this on llc, can you verify it works on real hardware.