[llvm] r364515 - [DebugInfo] Avoid register coalesing unsoundly changing DBG_VALUE locations

[Jeremy Morse via llvm-commits]

I've done a couple of stage2-with-asan builds and have found
AMDGPUDisassembler.cpp has a large jump in RegisterCoalescing time --
from 2 seconds to 41 seconds. I guess I'll get digging there.

(And will probably add asan-build-profiles to my testing regime ._.)

--
Thanks,
Jeremy