don't add nodes to the now-dead nodes list multiple times, this
can cause a crash on crazy situations in msp430 when morph-node-to
is disabled.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99739 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 600557e..3981826 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -1592,8 +1592,9 @@
       assert(ChainVal.getValueType() == MVT::Other && "Not a chain?");
       CurDAG->ReplaceAllUsesOfValueWith(ChainVal, InputChain, &ISU);
       
-      // If the node became dead, delete it.
-      if (ChainNode->use_empty())
+      // If the node became dead and we haven't already seen it, delete it.
+      if (ChainNode->use_empty() &&
+          !std::count(NowDeadNodes.begin(), NowDeadNodes.end(), ChainNode))
         NowDeadNodes.push_back(ChainNode);
     }
   }