diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1722,6 +1722,8 @@
         if (ShAmt < InnerBits && DemandedBits.getActiveBits() <= InnerBits &&
             isTypeDesirableForOp(ISD::SHL, InnerVT)) {
           EVT ShTy = getShiftAmountTy(InnerVT, DL);
+          if (ShTy.isScalableVector())
+            return false;
           if (!APInt(BitWidth, ShAmt).isIntN(ShTy.getSizeInBits()))
             ShTy = InnerVT;
           SDValue NarrowShl =