Fix the "partial pool allocator" on em3d and others. The problem is that

DSNodes, unlike other GraphTraits nodes, can have null outgoing edges, and
df_iterator doesn't take this into consideration.  As a workaround, the
successor iterator now handles null nodes and 'indicates' that null has
no successors.

llvm-svn: 12025

1 files changed, 8 insertions, 4 deletions

diff --git a/llvm/include/llvm/Analysis/DSGraphTraits.h b/llvm/include/llvm/Analysis/DSGraphTraits.h
index 72541b8cd1f..017d86f0b54 100644
--- a/llvm/include/llvm/Analysis/DSGraphTraits.h
+++ b/llvm/include/llvm/Analysis/DSGraphTraits.h
@@ -33,10 +33,14 @@ class DSNodeIterator : public forward_iterator<const DSNode, ptrdiff_t> {
 
   DSNodeIterator(NodeTy *N) : Node(N), Offset(0) {}   // begin iterator
   DSNodeIterator(NodeTy *N, bool) : Node(N) {         // Create end iterator
-    Offset = N->getNumLinks() << DS::PointerShift;
-    if (Offset == 0 && Node->getForwardNode() &&
-        Node->isDeadNode())        // Model Forward link
-      Offset += DS::PointerSize;
+    if (N != 0) {
+      Offset = N->getNumLinks() << DS::PointerShift;
+      if (Offset == 0 && Node->getForwardNode() &&
+          Node->isDeadNode())        // Model Forward link
+        Offset += DS::PointerSize;
+    } else {
+      Offset = 0;
+    }
   }
 public:
   DSNodeIterator(const DSNodeHandle &NH)