Add edge source labels to SelectionDAG graphs, now that the graph printing
framework omits differentiated edge sources in the case where the labels
are empty strings.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90254 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGPrinter.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGPrinter.cpp
index 74f7e51..83fa5a8 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGPrinter.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGPrinter.cpp
@@ -50,6 +50,11 @@
       return ((const SDNode *) Node)->getValueType(i).getEVTString();
     }
 
+    template<typename EdgeIter>
+    static std::string getEdgeSourceLabel(const void *Node, EdgeIter I) {
+      return itostr(I - SDNodeIterator::begin((SDNode *) Node));
+    }
+
     /// edgeTargetsEdgeSource - This method returns true if this outgoing edge
     /// should actually target another edge source, not a node.  If this method
     /// is implemented, getEdgeTarget should be implemented.