Implemented LowerVSELECT to custom lower some instructions.

No functionality change intended. The types that previously were set to
lower as Expand or Legal are doing the same thing with this lowering
function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209042 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed