// execution.
  if (llvm::isa<mlir::func::ReturnOp, mlir::quantfork::StatisticsOp>(op))
    return std::nullopt;

  if (!HasValidHardwareTarget(op)) return std::nullopt;

  auto device = op->getAttrOfType<mlir::StringAttr>(mlir::TFL::tac::kDevice);
  if (device == nullptr) return std::nullopt;

  llvm::StringRef device_name_str = device.getValue();
  return device_name_str.str();
}