Aggressively prune the DFS when inserting phi-defs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111394 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/include/llvm/ADT/DepthFirstIterator.h b/include/llvm/ADT/DepthFirstIterator.h
index b9e5cbdf8c..3edb555078 100644
--- a/include/llvm/ADT/DepthFirstIterator.h
+++ b/include/llvm/ADT/DepthFirstIterator.h
@@ -193,6 +193,15 @@ public:
   NodeType *getPath(unsigned n) const {
     return VisitStack[n].first.getPointer();
   }
+
+  /// skipChildren - Skip all children of Node, assuming that Node is on the
+  /// current path. This allows more aggressive pruning than just skipping
+  /// children of the current node.
+  _Self& skipChildren(NodeType *Node) {
+    while (!VisitStack.empty() && **this != Node)
+      VisitStack.pop_back();
+    return skipChildren();
+  }
 };