Revert r111394. It was too aggressive.

We must complete the DFS, otherwise we might miss needed phi-defs, and
prematurely color live ranges with a non-dominating value.

This is not a big deal since we get to color more of the CFG and the next
mapValue call will be faster.

llvm-svn: 111397

2 files changed, 3 insertions, 12 deletions

diff --git a/llvm/include/llvm/ADT/DepthFirstIterator.h b/llvm/include/llvm/ADT/DepthFirstIterator.h
index 3edb5550788..b9e5cbdf8c6 100644
--- a/llvm/include/llvm/ADT/DepthFirstIterator.h
+++ b/llvm/include/llvm/ADT/DepthFirstIterator.h
@@ -193,15 +193,6 @@ 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();
-  }
 };
 
 
diff --git a/llvm/lib/CodeGen/SplitKit.cpp b/llvm/lib/CodeGen/SplitKit.cpp
index dae282dfce6..b081bf37337 100644
--- a/llvm/lib/CodeGen/SplitKit.cpp
+++ b/llvm/lib/CodeGen/SplitKit.cpp
@@ -446,9 +446,9 @@ VNInfo *LiveIntervalMap::mapValue(const VNInfo *ParentVNI, SlotIndex Idx) {
     }
 
     // No need to search the children, we found a dominating value.
-    // MBB is either the found dominating value, or the last phi-def we created.
-    // Either way, the children of MBB would be shadowed, so don't search them.
-    IDFI.skipChildren(MBB);
+    // FIXME: We could prune up to the last phi-def we inserted, need df_iterator
+    // for that.
+    IDFI.skipChildren();
   }
 
   // The search should at least find a dominating value for IdxMBB.