diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index a3b617ede26..4576f3ce20b 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -6162,7 +6162,7 @@ static SDValue LowerAVXCONCAT_VECTORS(SDValue Op, SelectionDAG &DAG) {
 }
 
 static SDValue LowerCONCAT_VECTORS(SDValue Op, SelectionDAG &DAG) {
-  MVT VT = Op.getSimpleValueType();
+  MVT LLVM_ATTRIBUTE_UNUSED VT = Op.getSimpleValueType();
   assert((VT.is256BitVector() && Op.getNumOperands() == 2) ||
          (VT.is512BitVector() && (Op.getNumOperands() == 2 ||
           Op.getNumOperands() == 4)));