if x.Else != nil {
			r := d.reachable
			d.reachable = true
			d.findDead(x.Else)
			d.reachable = d.reachable || r
		} else {
			// might not have executed if statement
			d.reachable = true
		}

	case *ast.LabeledStmt:
		d.findDead(x.Stmt)

	case *ast.RangeStmt:
		d.findDead(x.Body)
		d.reachable = true

	case *ast.ReturnStmt:
		d.reachable = false

	case *ast.SelectStmt:

			}
			if !reachable[c.ID] {
				reachable[c.ID] = true
				p = append(p, c) // push
			}
		}
	}
	return reachable
}

// liveValues returns the live values in f and a list of values that are eligible
// to be statements in reversed data flow order.
// The second result is used to help conserve statement boundaries for debugging.
// reachable is a map from block ID to whether the block is reachable.

	fmt.Fprintln(p.w, f.Type)
}

func (p stringFuncPrinter) startBlock(b *Block, reachable bool) {
	if !p.printDead && !reachable {
		return
	}
	fmt.Fprintf(p.w, "  b%d:", b.ID)
	if len(b.Preds) > 0 {
		io.WriteString(p.w, " <-")
		for _, e := range b.Preds {
			pred := e.b
			fmt.Fprintf(p.w, " b%d", pred.ID)
		}
	}
	if !reachable {
		fmt.Fprint(p.w, " DEAD")
	}
	io.WriteString(p.w, "\n")
}

namespace tensorflow {

// Checks if a graph or reachable functions in the library have any
// StatefulPartitionedOps with _XlaMustCompile=true. The function library will
// be skipped if nullptr is provided.
bool IsSupportedByNonReplicatedBridge(
    const Graph& graph, const FunctionLibraryDefinition* function_library);

// Checks if a graph or reachable functions in the library have any ops with

//
// There are three ways a method of a reachable type can be invoked:
//
//  1. direct call
//  2. through a reachable interface type
//  3. reflect.Value.Method (or MethodByName), or reflect.Type.Method
//     (or MethodByName)
//
// The first case is handled by the flood fill, a directly called method
// is marked as reachable.
//
// The second case is handled by decomposing all reachable interface

	// To help catch disconnected-graph bugs, enforce that all required versions
	// are actually reachable from the roots (and therefore should affect the
	// selected versions of the modules they name).
	if _, reachable := g.isRoot[m]; !reachable {
		panic(fmt.Sprintf("%v is not reachable from any root", m))
	}

	// Truncate reqs to its capacity to avoid aliasing bugs if it is later

  SymbolUserMap symbol_map(table, module);

  // Create map from caller to set of all callee(s).
  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

  // Visit fetches first to create a starting point for ops that are reachable.
  reachable_ops.insert(graph.GetFetch());
  VisitOpOperands(graph, graph.GetFetch(), &reachable_ops, &ops_to_visit);

  // Find and visit ops that should be preserved regardless of being reachable
  // from a fetch.
  for (Operation& op : graph.GetBody().without_terminator()) {
    auto island = llvm::dyn_cast<IslandOp>(op);

  }

  /**
   * Creates a new traverser for the given general {@code graph}.
   *
   * <p>Traversers created using this method are guaranteed to visit each node reachable from the
   * start node(s) at most once.
   *
   * <p>If you know that no node in {@code graph} is reachable by more than one path from the start
   * node(s), consider using {@link #forTree(SuccessorsFunction)} instead.
   *
   * <p><b>Performance notes</b>
   *

  }

  /**
   * Creates a new traverser for the given general {@code graph}.
   *
   * <p>Traversers created using this method are guaranteed to visit each node reachable from the
   * start node(s) at most once.
   *
   * <p>If you know that no node in {@code graph} is reachable by more than one path from the start
   * node(s), consider using {@link #forTree(SuccessorsFunction)} instead.
   *
   * <p><b>Performance notes</b>
   *