diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index e113dbc67601..6ea5ee15d02c 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -6393,7 +6393,8 @@ static bool getFauxShuffleMask(SDValue N, SmallVectorImpl<int> &Mask,
       return false;
     SmallVector<int, 64> SubMask;
     SmallVector<SDValue, 2> SubInputs;
-    if (!resolveTargetShuffleInputs(Sub, SubInputs, SubMask, DAG))
+    if (!resolveTargetShuffleInputs(Sub, SubInputs, SubMask, DAG) ||
+        SubMask.size() != NumSubElts)
       return false;
     Ops.push_back(Src);
     for (SDValue &SubInput : SubInputs) {