// For a block argument, consider transforms only when it is a replicated
      // input (defining ops will be outside the replicate node).
      if (maybe_replicate == block_arg.getParentRegion()->getParentOp()) {
        HandleHostReplicatedInputs(input.index(), cluster_func, block_arg,
                                   maybe_replicate, block_size);
      }
    } else {

  absl::flat_hash_set<Region*> regions_with_token;
  while (!worklist.empty()) {
    Operation* op = worklist.back();
    worklist.pop_back();

    Region* region = op->getParentRegion();
    regions_with_token.insert(region);

    // If the parent is not a FuncOp, then add the parent op containing a region
    // to worklist.
    Operation* parent = region->getParentOp();

                   ArgMatcherFn matcher) {
  if (first.getNumOperands() != second.getNumOperands()) return false;

  Region& first_region = *first->getParentRegion();
  Region& second_region = *second->getParentRegion();

  for (auto it : llvm::zip(first.getArgOperands(), second.getArgOperands())) {
    // Get the defining Op, skipping over casts.
    auto get_defining_op = [](Value value) {

  }

  return func.getName().str();
}

absl::StatusOr<std::unique_ptr<NodeDef>> Exporter::GetArgumentNode(
    BlockArgument arg, unsigned index, llvm::StringRef name) {
  auto func = arg.getParentRegion()->getParentOfType<FuncOp>();

  auto node_def = std::make_unique<NodeDef>();
  if (!name.empty())
    node_def->set_name(std::string(ParseTensorName(name.str()).node()));
  else
    node_def->set_name(

  }

  return func.getName().str();
}

absl::StatusOr<std::unique_ptr<NodeDef>> Exporter::GetArgumentNode(
    BlockArgument arg, unsigned index, llvm::StringRef name) {
  auto func = arg.getParentRegion()->getParentOfType<FuncOp>();

  auto node_def = std::make_unique<NodeDef>();
  if (!name.empty())
    node_def->set_name(std::string(ParseTensorName(name.str()).node()));
  else
    node_def->set_name(

  // multiple TPU clusters.
  Region* region = (*forward_pass_ops.begin())->getParentRegion();
  StringAttr replication_attr = GetReplicationAttr(*forward_pass_ops.begin());
  llvm::SmallVector<Operation*> checkset(forward_pass_ops.getArrayRef());
  checkset.append(backward_pass_ops.begin(), backward_pass_ops.end());
  for (Operation* op : checkset) {
    if (op->getParentRegion() != region) {

      // within other sub-regions attached to ops in this region. So the check
      // for whether a user is in one of the regions attached to this op is
      // straightforward.
      if (user->getParentRegion()->getParentOp() != op_) continue;

      // For functions, if the resource is used as a return operand, use that
      // as its result index.
      if (is_func && isa<func::ReturnOp>(user)) {

  Region* region = (*forward_pass_ops.begin())->getParentRegion();
  StringAttr replication_attr = GetReplicationAttr(*forward_pass_ops.begin());
  llvm::SmallVector<Operation*> checkset(forward_pass_ops.getArrayRef());
  checkset.append(backward_pass_ops.begin(), backward_pass_ops.end());
  for (Operation* op : checkset) {
    if (op->getParentRegion() != region) {

  // `mhlo.while` cond terminator does not need to be rewritten as it always
  // returns a tensor<i1> predicate value.
  if (auto while_parent = dyn_cast_or_null<WhileOp>(terminator->getParentOp()))
    if (terminator->getParentRegion() == &while_parent.getCond()) return;

  builder.setInsertionPoint(terminator);
  llvm::SmallDenseMap<Value, Value> rewritten_operands;
  auto new_results =

    RegionBranchPoint point) {
  if (auto whileOp =
          llvm::dyn_cast<WhileRegionOp>(this->getOperation()->getParentOp())) {
    if (&whileOp.getCond() == this->getOperation()->getParentRegion()) {
      // cut off the boolean (the condition itself) at the start
      return MutableOperandRange(
          this->getOperation(), 1,
          this->getOperation()->getOperands().size() - 1);
    }