Fix a codegen abort seen in 483.xalancbmk.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93417 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 69a7a97..549527c 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1684,6 +1684,9 @@
   EVT VT = N0.getValueType();
   assert(N0.getOpcode() == N1.getOpcode() && "Bad input!");
 
+  // Bail early if none of these transforms apply.
+  if (N0.getNode()->getNumOperands() == 0) return SDValue();
+
   // For each of OP in AND/OR/XOR:
   // fold (OP (zext x), (zext y)) -> (zext (OP x, y))
   // fold (OP (sext x), (sext y)) -> (sext (OP x, y))