auto range = llvm::make_filter_range(op->getUsers(), [&](Operation *user) {
      bool same_block = user->getBlock() == op->getBlock();
      bool same_device = op->getAttr(kDeviceAttr) == user->getAttr(kDeviceAttr);
      return same_block && same_device && state.IsMember(user);
    });
    return {range.begin(), range.end()};
  }

  // Users of block argument must be in the same block.