Operation* new_op = Operation::create(
      op_->getLoc(), op_->getName(), new_result_types, op_->getOperands(),
      op_->getAttrs(), op_->getPropertiesStorage(), op_->getSuccessors(),
      op_->getNumRegions());
  builder.insert(new_op);

  // Move regions to the new op.
  for (auto it : llvm::zip(op_->getRegions(), new_op->getRegions())) {
    Region& old_region = std::get<0>(it);