Don't replace the old Ordering object with a new one; just clear()
the old one.

llvm-svn: 106284
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 91df1ab..c421e85 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -833,8 +833,7 @@
   EntryNode.UseList = 0;
   AllNodes.push_back(&EntryNode);
   Root = getEntryNode();
-  delete Ordering;
-  Ordering = new SDNodeOrdering();
+  Ordering->clear();
   DbgInfo->clear();
 }