We were assuming all SBFX-like operations would have the shl/asr form, but
often when the field being extracted is an i8 or i16, we end up with a
SIGN_EXTEND_INREG acting on a shift instead. Simple enough to check for though.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213754 91177308-0d34-0410-b5e6-96231b3b80d8