Index: lib/Target/ARM/ARMISelLowering.cpp
===================================================================
--- lib/Target/ARM/ARMISelLowering.cpp
+++ lib/Target/ARM/ARMISelLowering.cpp
@@ -5800,6 +5800,12 @@
   return VT == MVT::v8i8 && M.size() == 8;
 }
 
+static unsigned SelectPairHalf(unsigned Elements, ArrayRef<int> Mask, unsigned Index) {
+  if (Mask.size() == Elements * 2)
+    return Index / Elements;
+  return Mask[Index] == 0 ? 0 : 1;
+}
+
 // Checks whether the shuffle mask represents a vector transpose (VTRN) by
 // checking that pairs of elements in the shuffle mask represent the same index
 // in each vector, incrementing the expected index by 2 at each step.
@@ -5836,10 +5842,7 @@
   // element is undefined, e.g. [-1, 4, 2, 6] will be rejected, because only
   // M[0] is used to determine WhichResult
   for (unsigned i = 0; i < M.size(); i += NumElts) {
-    if (M.size() == NumElts * 2)
-      WhichResult = i / NumElts;
-    else
-      WhichResult = M[i] == 0 ? 0 : 1;
+    WhichResult = SelectPairHalf(NumElts, M, i);
     for (unsigned j = 0; j < NumElts; j += 2) {
       if ((M[i+j] >= 0 && (unsigned) M[i+j] != j + WhichResult) ||
           (M[i+j+1] >= 0 && (unsigned) M[i+j+1] != j + NumElts + WhichResult))
@@ -5866,10 +5869,7 @@
     return false;
 
   for (unsigned i = 0; i < M.size(); i += NumElts) {
-    if (M.size() == NumElts * 2)
-      WhichResult = i / NumElts;
-    else
-      WhichResult = M[i] == 0 ? 0 : 1;
+    WhichResult = SelectPairHalf(NumElts, M, i);
     for (unsigned j = 0; j < NumElts; j += 2) {
       if ((M[i+j] >= 0 && (unsigned) M[i+j] != j + WhichResult) ||
           (M[i+j+1] >= 0 && (unsigned) M[i+j+1] != j + WhichResult))
@@ -5901,10 +5901,7 @@
     return false;
 
   for (unsigned i = 0; i < M.size(); i += NumElts) {
-    if (M.size() == NumElts * 2)
-      WhichResult = i / NumElts;
-    else
-      WhichResult = M[i] == 0 ? 0 : 1;
+    WhichResult = SelectPairHalf(NumElts, M, i);
     for (unsigned j = 0; j < NumElts; ++j) {
       if (M[i+j] >= 0 && (unsigned) M[i+j] != 2 * j + WhichResult)
         return false;
@@ -5935,10 +5932,7 @@
 
   unsigned Half = NumElts / 2;
   for (unsigned i = 0; i < M.size(); i += NumElts) {
-    if (M.size() == NumElts * 2)
-      WhichResult = i / NumElts;
-    else
-      WhichResult = M[i] == 0 ? 0 : 1;
+    WhichResult = SelectPairHalf(NumElts, M, i);
     for (unsigned j = 0; j < NumElts; j += Half) {
       unsigned Idx = WhichResult;
       for (unsigned k = 0; k < Half; ++k) {
@@ -5978,10 +5972,7 @@
     return false;
 
   for (unsigned i = 0; i < M.size(); i += NumElts) {
-    if (M.size() == NumElts * 2)
-      WhichResult = i / NumElts;
-    else
-      WhichResult = M[i] == 0 ? 0 : 1;
+    WhichResult = SelectPairHalf(NumElts, M, i);
     unsigned Idx = WhichResult * NumElts / 2;
     for (unsigned j = 0; j < NumElts; j += 2) {
       if ((M[i+j] >= 0 && (unsigned) M[i+j] != Idx) ||
@@ -6014,10 +6005,7 @@
     return false;
 
   for (unsigned i = 0; i < M.size(); i += NumElts) {
-    if (M.size() == NumElts * 2)
-      WhichResult = i / NumElts;
-    else
-      WhichResult = M[i] == 0 ? 0 : 1;
+    WhichResult = SelectPairHalf(NumElts, M, i);
     unsigned Idx = WhichResult * NumElts / 2;
     for (unsigned j = 0; j < NumElts; j += 2) {
       if ((M[i+j] >= 0 && (unsigned) M[i+j] != Idx) ||