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llvm-svn: 128730

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -4929,9 +4929,11 @@ void SelectionDAGBuilder::LowerCallTo(ImmutableCallSite CS, SDValue Callee,
                          &ReturnValues[0], ReturnValues.size()));
   }
 
-  // As a special case, a null chain means that a tail call has been emitted and
-  // the DAG root is already updated.
+  // Assign order to nodes here. If the call does not produce a result, it won't
+  // be mapped to a SDNode and visit() will not assign it an order number.
   if (!Result.second.getNode()) {
+    // As a special case, a null chain means that a tail call has been emitted and
+    // the DAG root is already updated.
     HasTailCall = true;
     ++SDNodeOrder;
     AssignOrderingToNode(DAG.getRoot().getNode());