diff --git a/lib/Target/AArch64/AArch64ISelLowering.cpp b/lib/Target/AArch64/AArch64ISelLowering.cpp
index 430938e2f43..5ccc4bf9ff4 100644
--- a/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -7994,18 +7994,18 @@ static SDValue performVSelectCombine(SDNode *N, SelectionDAG &DAG) {
 static SDValue performSelectCombine(SDNode *N, SelectionDAG &DAG) {
   SDValue N0 = N->getOperand(0);
   EVT ResVT = N->getValueType(0);
-  EVT SrcVT = N0.getOperand(0).getValueType();
-  int NumMaskElts = ResVT.getSizeInBits() / SrcVT.getSizeInBits();
+
+  if (N0.getOpcode() != ISD::SETCC || N0.getValueType() != MVT::i1)
+    return SDValue();
 
   // If NumMaskElts == 0, the comparison is larger than select result. The
   // largest real NEON comparison is 64-bits per lane, which means the result is
   // at most 32-bits and an illegal vector. Just bail out for now.
+  EVT SrcVT = N0.getOperand(0).getValueType();
+  int NumMaskElts = ResVT.getSizeInBits() / SrcVT.getSizeInBits();
   if (!ResVT.isVector() || NumMaskElts == 0)
     return SDValue();
 
-  if (N0.getOpcode() != ISD::SETCC || N0.getValueType() != MVT::i1)
-    return SDValue();
-
   SrcVT = EVT::getVectorVT(*DAG.getContext(), SrcVT, NumMaskElts);
   EVT CCVT = SrcVT.changeVectorElementTypeToInteger();
 
diff --git a/test/CodeGen/AArch64/cond-sel.ll b/test/CodeGen/AArch64/cond-sel.ll
index 333f2436133..dfc83aacfcf 100644
--- a/test/CodeGen/AArch64/cond-sel.ll
+++ b/test/CodeGen/AArch64/cond-sel.ll
@@ -224,3 +224,10 @@ define <1 x i1> @test_wide_comparison(i32 %in) {
   %res = select i1 %tmp, <1 x i1> <i1 1>, <1 x i1> zeroinitializer
   ret <1 x i1> %res
 }
+
+define i32 @test_select_undef() {
+; CHECK-LABEL: test_select_undef:
+; CHECK: ret
+  %res = select i1 undef, i32 0, i32 42
+  ret i32 %res
+}