eliminate some ops if they have an undef RHS


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34908 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 2679a8c..0de7120 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1325,6 +1325,8 @@
   if (N2.getOpcode() == ISD::UNDEF) {
     switch (Opcode) {
     case ISD::ADD:
+    case ISD::ADDC:
+    case ISD::ADDE:
     case ISD::SUB:
     case ISD::FADD:
     case ISD::FSUB: