1 files changed, 3 insertions, 4 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index eed3d820c120..d9cde609e599 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -21361,10 +21361,9 @@ static SDValue reduceBuildVecToShuffleWithZero(SDNode *BV, SelectionDAG &DAG) {
       // the source vector. The high bits map to zero. We will use a zero vector
       // as the 2nd source operand of the shuffle, so use the 1st element of
       // that vector (mask value is number-of-elements) for the high bits.
-      if (i % ZextRatio == 0)
-        ShufMask[i] = Extract.getConstantOperandVal(1);
-      else
-        ShufMask[i] = NumMaskElts;
+      int Low = DAG.getDataLayout().isBigEndian() ? (ZextRatio - 1) : 0;
+      ShufMask[i] = (i % ZextRatio == Low) ? Extract.getConstantOperandVal(1)
+                                           : NumMaskElts;
     }
 
     // Undef elements of the build vector remain undef because we initialize