Remove unused argument.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183992 91177308-0d34-0410-b5e6-96231b3b80d8
SelectionDAG: Fix incorrect condition checks in some cases of folding FADD/FMUL combinations; also improve accuracy of comments


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183993 91177308-0d34-0410-b5e6-96231b3b80d8