if (it != infos.end() && !it->getSecond().used) {
        return_op->eraseOperand(entry.index() - skipped_retvals++);
      }
    }
  }
  llvm::BitVector indices_to_erase(func_op.getNumArguments());
  llvm::SmallVector<Type, 4> new_types;
  int64_t skipped_args = 0;
  for (auto arg : func_op.getArguments()) {
    auto it = infos.find(arg.getArgNumber());
    if (it != infos.end() && !it->getSecond().used) {

                                   updated_result_types));
  });
  Region &entry = func.getRegion();
  TypeConverter::SignatureConversion signature_conversion(
      entry.getNumArguments());
  for (const BlockArgument &arg : entry.getArguments()) {
    signature_conversion.addInputs(arg.getArgNumber(),
                                   updated_argument_types[arg.getArgNumber()]);
  }