void MergeIfPerSegment(
    llvm::SmallVector<TF::IfRegionOp, 8>& if_op_segment,
    llvm::SmallVector<Operation*, 8>& moved_ops_list,
    llvm::SmallSetVector<TF::IfRegionOp, 8>& regions_to_remove,
    llvm::SmallDenseMap<Operation*, TF::IfRegionOp>& old_to_new_IfRegion_map) {
  TF::IfRegionOp first_if = if_op_segment[0];
  llvm::SmallVector<Type, 4> merged_return_types;
  llvm::SmallVector<TF::IfRegionOp, 8> sources_if_ops(

  builder.create<YieldOp>(loc, cond_block->getArgument(0));
}

// Create an IfRegionOp with a predicate from `optional_has_value`.  If true, it
// uses `get_next` to get the next value and calls `reduce_func`.  `body_args`
// is used as pass through of state values for else branch.  `dataset_types` is
// used for constructing the CallOp for `reduce_func`.
IfRegionOp CreateOptionalDatasetIf(

  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(),

    callee_names = {first_call.value().getCallee(),
                    second_call.value().getCallee()};
  }
};

// Transform IfRegionOp to IfOp.
LogicalResult RegionControlFlowToFunctional::ConvertIfOp(
    SymbolTableCollection& symbol_table, IfRegionOp if_region) {
  llvm::SmallVector<Value, 4> extern_values;

  // For IfOp, arguments of calls in the then and else regions match if they

  }
  while_op.replaceAllUsesWith(
      new_while.getResults().take_front(while_op.getNumResults()));
  while_op.erase();
  return success();
}

LogicalResult HandleIfRegionOp(
    TF::IfRegionOp if_op, ModuleOp module,
    llvm::SmallDenseMap<Value, SizeInfo>* buffer_to_size,
    llvm::StringMap<PartitionedCallDecompositionInfo>*
        decomposed_partitioned_call_callees) {
  // Rewrite the branches.

      op);
}

// Returns true if the given op is one of ops supported to have communication
// subcomputation in the TF/XLA bridge.
bool SupportsCommunicationComputation(Operation* op) {
  return isa<TF::IfRegionOp, TF::WhileRegionOp, TF::CaseRegionOp,
             TF::XlaCallModuleOp, TF::StatefulPartitionedCallOp,
             TF::PartitionedCallOp, TF::LegacyCallOp>(op);
}

#define GEN_PASS_DEF_PREPARETPUCOMPUTATIONFORTFEXPORTPASS

                       IRMapping &valueMapping) const final {
    // Allow inlining in regions attached to region based control flow
    // operations only if the src region is a single block region
    return isa<IfRegionOp, CaseRegionOp, WhileRegionOp>(dest->getParentOp()) &&
           llvm::hasSingleElement(*src);
  }

  // Returns true if its legal to inline a TF operation `op` into the `dest`
  // region.

        AddRegionSideEffectsForOp(branch_func.getBody(), op);
      }
    } else if (isa<tf_device::LaunchOp, tf_device::ClusterOp,
                   tf_executor::IslandOp, tf_executor::GraphOp, IfRegionOp,
                   CaseRegionOp>(op)) {
      for (Region& region : op->getRegions()) {
        AddRegionSideEffectsForOp(region, op);
      }
    } else if (auto xla_call_module_op = dyn_cast<XlaCallModuleOp>(op)) {

      (*arguments_to_erase)[callee].push_back(argument_index - 1);
      work_list->push_back(
          std::make_pair(&callee.getBody(), argument_index - 1));
    }
  } else if (auto if_op = dyn_cast<TF::IfRegionOp>(user_op)) {
    (*arguments_to_erase)[if_op].push_back(argument_index);
    for (auto callee : {&if_op.getThenBranch(), &if_op.getElseBranch()}) {
      work_list->push_back(std::make_pair(callee, argument_index));
    }

      if (while_op.cond_function().walk(check_while_cond).wasInterrupted())
        return WalkResult::interrupt();
      result = CanonicalizeFunctionalWhile(while_op);
    } else if (isa<TF::IfRegionOp, TF::CaseRegionOp, tf_device::ClusterOp>(
                   op)) {
      result = CanonicalizeRegionIfCaseCluster(op);
    } else if (auto while_region = dyn_cast<TF::WhileRegionOp>(op)) {