<< "Cannot find function " << sym.getRootReference();
    }
    callees.push_back(callee);
  }
  return success();
}

bool HasSingleBlock(func::FuncOp func) {
  return func->getNumRegions() == 1 && func.getBody().hasOneBlock();
}

                               output_types, candidate_op->getAttrs());
      for (int i = 0; i < candidate_op->getNumRegions(); ++i) {
        new_state.addRegion();
      }
      Operation* quantized_op = rewriter.create(new_state);
      if (candidate_op->getNumRegions() != 0) {
        for (const auto& indexed_regions :
             llvm::enumerate(candidate_op->getRegions())) {

// This is a lengthy bit of code, since it has to recreate the operation.
// TODO(kramm): Move this under utils/ somewhere.
void EraseResults(Operation* op, llvm::BitVector erase) {
  assert(!op->getNumRegions());
  std::vector<Type> result_types;
  for (auto result : op->getResults()) {
    if (!erase[result.getResultNumber()]) {
      result_types.push_back(result.getType());
    }
  }
  OpBuilder builder(op);

  // could be folded should have a custom folder instead of relying on the
  // TensorFlow folding hook.
  if (inst == nullptr || inst->getNumResults() == 0 ||
      inst->hasTrait<OpTrait::TF::NoConstantFold>() ||
      inst->getNumRegions() != 0 || !isMemoryEffectFree(inst)) {
    return false;
  }

  // If any of the result types are variants, don't try to constant fold them.
  // This creates opaque variant constants which lose information and would

  }

  void runOnOperation() override;
};

// Returns true iff func_op has either no Region or the body has no Blocks.
bool IsFuncOpEmpty(func::FuncOp func_op) {
  return func_op->getNumRegions() == 0 || func_op.getBody().empty();
}

// Gets the GraphOp from the function op. Returns an empty op iff it doesn't
// exist.
GraphOp GetGraphOpFromFuncOp(func::FuncOp func_op) {

                               output_types, quantizing_op->getAttrs());
      for (int i = 0; i < quantizing_op->getNumRegions(); ++i) {
        new_state.addRegion();
      }
      Operation* quantized_op = rewriter.create(new_state);
      if (quantizing_op->getNumRegions() != 0) {
        for (const auto& indexed_regions :
             llvm::enumerate(quantizing_op->getRegions())) {
          IRMapping mapping;

        }
      }
    } else if (isa<tf_device::LaunchOp, tf_device::ClusterOp,
                   tf_executor::IslandOp, tf_executor::GraphOp>(op) &&
               op->getNumRegions() == 1) {
      Region& region = op->getRegion(0);
      const auto& body_info = backtrack_analysis.GetAnalysisForRegion(region);
      for (auto result : filter_resources(op->getResults())) {

  }

  num_new_results_ = op_->getNumResults();

  for (auto resource : all_resources) {
    ResourceInfo info;
    info.data_type = GetResourceSubtype(resource);
    llvm::BitVector written_regions(op_->getNumRegions());
    bool unsupported_use = false;
    for (OpOperand& use : resource.getUses()) {
      Operation* user = use.getOwner();
      // If the user is not in one of the regions, we are not interested in it.

                tf_saved_model::TensorFlowSavedModelDialect>();
  }
};

// Returns true iff func_op has either no Region or the body has no Blocks.
bool IsFuncOpEmpty(func::FuncOp func_op) {
  return func_op->getNumRegions() == 0 || func_op.getBody().empty();
}

// Gets the GraphOp from the function op. Returns an empty op iff it doesn't
// exist.
GraphOp GetGraphOpFromFuncOp(func::FuncOp func_op) {

  builder.setInsertionPoint(region_if);

  if (!region_idx) {
    RewriteRegionIfOp(builder, region_if, ops_to_visit, token);
    return true;
  }

  if (*region_idx < region_if.getNumRegions()) {
    // For the region-blocks of If op, we create a dummy token argument. Later
    // we replace that block-argument's uses with the same (implicitly captured)
    // token 'token', used for If op, and erase the argument.