diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index efc0781260760ea2a003e672449845b672c038bf..6ebbf871995a59a8e264c3348dfb923b83d883fe 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -101,7 +101,8 @@ static SDValue ExtractSubVector(SDValue Vec, unsigned IdxVal,
 /// lowering EXTRACT_VECTOR_ELT operations easier.
 static SDValue Extract128BitVector(SDValue Vec, unsigned IdxVal,
                                    SelectionDAG &DAG, SDLoc dl) {
-  assert(Vec.getValueType().is256BitVector() && "Unexpected vector size!");
+  assert((Vec.getValueType().is256BitVector() ||
+          Vec.getValueType().is512BitVector()) && "Unexpected vector size!");
   return ExtractSubVector(Vec, IdxVal, DAG, dl, 128);
 }