auto num_loop_carried = while_op.getCond().getNumArguments();
  auto not_carried_operands =
      while_op.getOperands().drop_front(num_loop_carried);
  extern_values.insert(not_carried_operands.begin(),
                       not_carried_operands.end());
  auto old_extern_values_size = extern_values.size();

  llvm::SmallVector<Region*, 2> regions{&while_op.getCond(),

  Block &cond = while_op.getCond().front();
  Block &body = while_op.getBody().front();

  auto n = while_op.getNumOperands();
  if (!AllOperationSafe(cond) || !AllOperationSafe(body)) return false;

  // Find all Consumed indices.
  // i is consumed element if result(i) is used outside whileOp or
  // argument(i) is used in whileOp.getCond().
  for (auto i = 0; i < n; ++i) {

      while_op->erase();
    } else if (auto while_op = dyn_cast<TF::WhileRegionOp>(user_op)) {
      auto new_while_op = GetUpdatedWhileOp(
          while_op, while_op.getCond().getArgumentTypes(), args_to_erase);
      new_while_op.getCond().takeBody(while_op.getCond());
      new_while_op.getBody().takeBody(while_op.getBody());
      llvm::BitVector erase_indices;
      UpdateTerminatorArguments(new_while_op.getBody(), args_to_erase,

    // integers. Thus, we use the `tensor.extract` op to compute the condition
    // of `scf.if` from that of `tf.IfRegion`.
    auto scf_if_condition =
        rewriter.create<tensor::ExtractOp>(loc, op.getCond());

    TypeRange tf_if_region_return_type = op.getResultTypes();

    // Create the `scf.if` op.
    auto scf_if_op =
        rewriter.create<scf::IfOp>(loc, tf_if_region_return_type,

      op->getLoc(), op->getResultTypes(), op->getOperands(),
      while_op.getIsStateless());
  Location loc = while_op->getLoc();
  CreateRegionWithCall(while_op.cond_function(), new_op.getCond(), loc);
  CreateRegionWithCall(while_op.body_function(), new_op.getBody(), loc);

  op->replaceAllUsesWith(new_op.getResults());
  op->erase();
}

void LegalizeWhilePass::RunOnFunction(func::FuncOp func) {

  return to_bool;
}

// Transform a functional IfOp to a region based IfRegionOp.
LogicalResult ConvertIfOp(IfOp if_op) {
  Value cond = ConvertConditionToBoolean(if_op, if_op.getCond());
  OpBuilder builder(if_op);
  auto if_region = builder.create<TF::IfRegionOp>(
      if_op.getLoc(), if_op.getResultTypes(), cond, if_op.getIsStateless(),
      builder.getStringAttr(if_op.then_function().getName()),

  // Don't prune if result is used.
  if (!result.use_empty()) return false;

  Block& body_block = while_op.getBody().front();
  Block& cond_block = while_op.getCond().front();
  Operation* body_yield_op = body_block.getTerminator();

  // The body yield operand, body block argument, condition block argument, and
  // result all correspond to each other (see definition of `WhileRegionOp`).

    regions.push_back(
        RegionSuccessor(&getCond(), getCond().front().getArguments()));
  } else if (point.isParent()) {
    // The parent branches to 'cond'. It is also considered to branch to `body`
    // in case the terminator of `cond` doesn't forward the arguments of `cond`.
    regions.push_back(
        RegionSuccessor(&getCond(), getCond().front().getArguments()));
    regions.push_back(

      grouped_if_ops;
  llvm::SmallVector<Value, 4> if_cond_order;
  block->walk([&](TF::IfRegionOp if_op) {
    auto it = grouped_if_ops.try_emplace(if_op.getCond());
    if (it.second) {
      if_cond_order.push_back(if_op.getCond());
    }
    it.first->getSecond().push_back(if_op);
  });

  MapToRegionVec2D planned_merged_groups;
  MapToOperationVec2D moved_ops_groups;

        worklist, /*extern_values_passthrough=*/false,
        /*only_one_return_value=*/false);
  }

  // Look through ToBool operations for the condition.
  Value cond = if_region.getCond();
  auto to_bool = dyn_cast_or_null<ToBoolOp>(cond.getDefiningOp());
  if (to_bool) cond = to_bool.getOperand();

  // Once we have the `then` and `else` functions ready (either outlined or