void runOnOperation() final;
};

// Returns the earlier value of which `v` is an identity. If `skipped` is
// provided, it will be used to store the identity nodes skipped.
Value SkipIdentity(Value v, bool allow_other_use,
                   llvm::SmallPtrSet<Operation*, 4>* skipped = nullptr) {
  while (auto result = mlir::dyn_cast<OpResult>(v)) {
    if (!(allow_other_use || v.hasOneUse())) break;