Fix a crash compiling Olden/tsp


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23630 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 19c61a5..9f83673 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1069,18 +1069,16 @@
   
   // Determine if the condition we're dealing with is constant
   SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC);
-  ConstantSDNode *SCCC = dyn_cast<ConstantSDNode>(SCC);
-  bool constTrue = SCCC && SCCC->getValue() == 1;
-  bool constFalse = SCCC && SCCC->isNullValue();
-    
+  ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
+  
   // fold select_cc lhs, rhs, x, x, cc -> x
   if (N2 == N3)
     return N2;
   // fold select_cc true, x, y -> x
-  if (constTrue)
+  if (SCCC && SCCC->getValue())
     return N2;
   // fold select_cc false, x, y -> y
-  if (constFalse)
+  if (SCCC && SCCC->getValue() == 0)
     return N3;
   // fold select_cc into other things, such as min/max/abs
   return SimplifySelectCC(N0, N1, N2, N3, CC);