const std::function<bool(SymbolUserOpInterface)> &predicate,
    llvm::SmallVector<SymbolUserOpInterface> &ops) {
  std::stack<func::FuncOp> worklist;
  worklist.push(root);
  while (!worklist.empty()) {
    func::FuncOp u = worklist.top();
    worklist.pop();
    auto result = u.walk([&](SymbolUserOpInterface op) {
      if (llvm::isa<T, Types...>(op) && (!predicate || predicate(op))) {
        ops.push_back(op);

  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();
    if (!isa<func::FuncOp>(parent)) {

    op_results_constraints[op].Insert(value, constraint);
  }

  // Keep a worklist of operations that need their constraints to be updated.
  llvm::SetVector<Operation *> worklist;
  for (Operation *op : root) worklist.insert(op);

  while (!worklist.empty()) {
    Operation *op = worklist.pop_back_val();

    // Use results constraints to infer operands constraints.

                 std::vector<IslandOp>& path) {
  std::queue<IslandOp> worklist;
  // Stores predecessor pointers.
  IslandToIslandHashMap pred_map;

  // BFS starting from `source_op`, stop when `target_op` is reached.
  worklist.push(source_op);
  while (!worklist.empty()) {
    IslandOp curr_op = worklist.front();
    worklist.pop();

    if (curr_op == target_op) break;

void RegionControlFlowToFunctional::runOnOperation() {
  ModuleOp module = getOperation();
  SymbolTableCollection symbol_table;

  // Seed worklist with all functions in the module.
  worklist = llvm::to_vector<4>(module.getOps<func::FuncOp>());
  while (!worklist.empty()) {
    func::FuncOp function = worklist.pop_back_val();

    auto result = function.walk([&](Operation* op) {
      if (auto if_region = llvm::dyn_cast<IfRegionOp>(op)) {

  mlir::Block* const cluster_block = cluster->getBlock();
  llvm::SetVector<mlir::Operation*> ops_to_reorder;

  llvm::SmallVector<mlir::Value> worklist;
  llvm::append_range(worklist, cluster->getResults());

  while (!worklist.empty()) {
    mlir::Value value = worklist.back();
    worklist.pop_back();

    for (mlir::Operation* const user : value.getUsers()) {

// need all uses of it, only uses that can become constants would be added into
// re-visit worklist since no matter how many times they are revisited, uses which
// can't become constants lattice remains unchanged, i.e. Bottom.
func (t *worklist) buildDefUses() {
	for _, block := range t.f.Blocks {
		for _, val := range block.Values {
			for _, arg := range val.Args {

  llvm::DenseMap<func::FuncOp, llvm::DenseSet<func::FuncOp>> caller_callee_map;

  // Use worklist to populate the set of reachable functions.
  std::queue<func::FuncOp> function_worklist;

  // Iterates over all functions within the module to (1) create caller-callee
  // map, and (2) initialize function worklist with functions referenced from
  // device cluster ops.
  for (auto func : module.getOps<func::FuncOp>()) {

          }
          // If the callee recording is modified, make sure that it will be
          // reprocessed.
          if (callee_needs_recompute) worklist.insert(callee);
        }
        return success();
      };

  while (!worklist.empty()) {
    auto func_op = worklist.pop_back_val();
    auto& func_res = per_function_results.find(func_op)->getSecond();
    // In-function propagation.

// running in parallel with earlier tests, or if it has some other reason
// for needing the earlier tests to be done.
func (t *tester) runPending(nextTest *distTest) {
	worklist := t.worklist
	t.worklist = nil
	for _, w := range worklist {
		w.start = make(chan bool)
		w.end = make(chan struct{})
		// w.cmd must be set up to write to w.out. We can't check that, but we
		// can check for easy mistakes.