Comment some and reformat for clarity beginFunction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193894 91177308-0d34-0410-b5e6-96231b3b80d8
LoopVectorizer: Move cse code into its own function

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193895 91177308-0d34-0410-b5e6-96231b3b80d8