[PATCH] D29767: GraphTraits: Add range versions of graph traits functions (graph_nodes, graph_children, inverse_graph_nodes, inverse_graph_children).

[Daniel Berlin via Phabricator via llvm-commits]

dberlin added inline comments.


================
Comment at: include/llvm/Support/GenericDomTreeConstruction.h:203
     WInfo.Semi = WInfo.Parent;
-    typedef GraphTraits<Inverse<NodeT> > InvTraits;
-    for (typename InvTraits::ChildIteratorType CI =
-         InvTraits::child_begin(W),
-         E = InvTraits::child_end(W); CI != E; ++CI) {
-      typename InvTraits::NodeRef N = *CI;
-      if (DT.Info.count(N)) {  // Only if this predecessor is reachable!
+    for (const auto &N : inverse_graph_children<NodeT>(W))
+      if (DT.Info.count(N)) { // Only if this predecessor is reachable!
----------------
Note that this use of const auto & is required to make clang build, as the iterator type it for CFG blocks ends up returning blocks directly otherwise here.

I'm not sure this is a legal definition of graphtraits, and the definition of CFG inverse graph traits is also definitely broken:
```

 template <> struct GraphTraits<Inverse< ::clang::CFGBlock*> > {
   typedef ::clang::CFGBlock *NodeRef;
-  typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType;
+  typedef ::clang::CFGBlock::pred_iterator ChildIteratorType;
```

(the constant iterator is being used for the non-constant version of inverse graphtraits, which looks like a paste error)

I don't usually work in clang world, so i added someone who does :)



https://reviews.llvm.org/D29767