Small optimization: once the size is know, we don't have to call fillCurWord.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221891 91177308-0d34-0410-b5e6-96231b3b80d8
Simplify code a bit. NFC.

Thanks to Sean Silva for the suggestion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221892 91177308-0d34-0410-b5e6-96231b3b80d8