[llvm] [NFC][DecoderEmitter] Arrange functions by class 1/N (PR #157107)

[Sergei Barannikov via llvm-commits]

================
@@ -697,6 +690,15 @@ Filter::Filter(ArrayRef<InstructionEncoding> Encodings,
          "Filter returns no instruction categories");
 }
 
+// Returns the number of fanout produced by the filter.  More fanout implies
+// the filter distinguishes more categories of instructions.
+unsigned Filter::usefulness() const {
+  return FilteredIDs.size() + VariableIDs.empty();
----------------
s-barannikov wrote:

This is so simple that it could be moved inside the class.

https://github.com/llvm/llvm-project/pull/157107