When figuring out which operands match which encoding fields in an instruction,

When figuring out which operands match which encoding fields in an instruction,
try to match them by name first. If there is no by-name match, fall back to
assuming they are in order (this was the previous behavior).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116211 91177308-0d34-0410-b5e6-96231b3b80d8