extension property we're requesting - zero or sign extended.
This fixes cases where we want to return a zero extended 32-bit -1
and not be sign extended for the entire register. Also updated the
already out of date comment with the current behavior.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243192 91177308-0d34-0410-b5e6-96231b3b80d8