Fiona Glaser b08ae7affb ComputeKnownBits: be a bit smarter about ADDs
If our two inputs have known top-zero bit counts M and N, we trivially
know that the output cannot have any bits set in the top (min(M, N)-1)
bits, since nothing could carry past that point.

llvm-svn: 241927
2015-07-10 18:29:02 +00:00
..