We assumed the output of a match was a Value, this would cause us to
assert because we would fail a cast<>. Instead, use a helper in the
Operator family to hide the distinction between Value and Constant.
This fixes PR22087.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225127 91177308-0d34-0410-b5e6-96231b3b80d8
07d7dbae9e