simplify expression

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190826 91177308-0d34-0410-b5e6-96231b3b80d8
mention command line parameters

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190827 91177308-0d34-0410-b5e6-96231b3b80d8