diff --git a/llvm/lib/Transforms/Scalar/Scalarizer.cpp b/llvm/lib/Transforms/Scalar/Scalarizer.cpp
--- a/llvm/lib/Transforms/Scalar/Scalarizer.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalarizer.cpp
@@ -174,7 +174,7 @@
   }
 
   // The type of the vector.
-  VectorType *VecTy = nullptr;
+  FixedVectorType *VecTy = nullptr;
 
   // The type of each element.
   Type *ElemTy = nullptr;
@@ -488,7 +488,7 @@
                                    const DataLayout &DL) {
   VectorLayout Layout;
   // Make sure we're dealing with a vector.
-  Layout.VecTy = dyn_cast<VectorType>(Ty);
+  Layout.VecTy = dyn_cast<FixedVectorType>(Ty);
   if (!Layout.VecTy)
     return std::nullopt;
   // Check that we're dealing with full-byte elements.
@@ -504,11 +504,11 @@
 // to create an instruction like I with operand X and name Name.
 template<typename Splitter>
 bool ScalarizerVisitor::splitUnary(Instruction &I, const Splitter &Split) {
-  VectorType *VT = dyn_cast<VectorType>(I.getType());
+  auto *VT = dyn_cast<FixedVectorType>(I.getType());
   if (!VT)
     return false;
 
-  unsigned NumElems = cast<FixedVectorType>(VT)->getNumElements();
+  unsigned NumElems = VT->getNumElements();
   IRBuilder<> Builder(&I);
   Scatterer Op = scatter(&I, I.getOperand(0));
   assert(Op.size() == NumElems && "Mismatched unary operation");
@@ -524,11 +524,11 @@
 // to create an instruction like I with operands X and Y and name Name.
 template<typename Splitter>
 bool ScalarizerVisitor::splitBinary(Instruction &I, const Splitter &Split) {
-  VectorType *VT = dyn_cast<VectorType>(I.getType());
+  auto *VT = dyn_cast<FixedVectorType>(I.getType());
   if (!VT)
     return false;
 
-  unsigned NumElems = cast<FixedVectorType>(VT)->getNumElements();
+  unsigned NumElems = VT->getNumElements();
   IRBuilder<> Builder(&I);
   Scatterer VOp0 = scatter(&I, I.getOperand(0));
   Scatterer VOp1 = scatter(&I, I.getOperand(1));
@@ -559,7 +559,7 @@
 /// If a call to a vector typed intrinsic function, split into a scalar call per
 /// element if possible for the intrinsic.
 bool ScalarizerVisitor::splitCall(CallInst &CI) {
-  VectorType *VT = dyn_cast<VectorType>(CI.getType());
+  auto *VT = dyn_cast<FixedVectorType>(CI.getType());
   if (!VT)
     return false;
 
@@ -571,7 +571,7 @@
   if (ID == Intrinsic::not_intrinsic || !isTriviallyScalariable(ID))
     return false;
 
-  unsigned NumElems = cast<FixedVectorType>(VT)->getNumElements();
+  unsigned NumElems = VT->getNumElements();
   unsigned NumArgs = CI.arg_size();
 
   ValueVector ScalarOperands(NumArgs);
@@ -624,11 +624,11 @@
 }
 
 bool ScalarizerVisitor::visitSelectInst(SelectInst &SI) {
-  VectorType *VT = dyn_cast<VectorType>(SI.getType());
+  auto *VT = dyn_cast<FixedVectorType>(SI.getType());
   if (!VT)
     return false;
 
-  unsigned NumElems = cast<FixedVectorType>(VT)->getNumElements();
+  unsigned NumElems = VT->getNumElements();
   IRBuilder<> Builder(&SI);
   Scatterer VOp1 = scatter(&SI, SI.getOperand(1));
   Scatterer VOp2 = scatter(&SI, SI.getOperand(2));
@@ -677,12 +677,12 @@
 }
 
 bool ScalarizerVisitor::visitGetElementPtrInst(GetElementPtrInst &GEPI) {
-  VectorType *VT = dyn_cast<VectorType>(GEPI.getType());
+  auto *VT = dyn_cast<FixedVectorType>(GEPI.getType());
   if (!VT)
     return false;
 
   IRBuilder<> Builder(&GEPI);
-  unsigned NumElems = cast<FixedVectorType>(VT)->getNumElements();
+  unsigned NumElems = VT->getNumElements();
   unsigned NumIndices = GEPI.getNumIndices();
 
   // The base pointer might be scalar even if it's a vector GEP. In those cases,
@@ -723,11 +723,11 @@
 }
 
 bool ScalarizerVisitor::visitCastInst(CastInst &CI) {
-  VectorType *VT = dyn_cast<VectorType>(CI.getDestTy());
+  auto *VT = dyn_cast<FixedVectorType>(CI.getDestTy());
   if (!VT)
     return false;
 
-  unsigned NumElems = cast<FixedVectorType>(VT)->getNumElements();
+  unsigned NumElems = VT->getNumElements();
   IRBuilder<> Builder(&CI);
   Scatterer Op0 = scatter(&CI, CI.getOperand(0));
   assert(Op0.size() == NumElems && "Mismatched cast");
@@ -741,13 +741,13 @@
 }
 
 bool ScalarizerVisitor::visitBitCastInst(BitCastInst &BCI) {
-  VectorType *DstVT = dyn_cast<VectorType>(BCI.getDestTy());
-  VectorType *SrcVT = dyn_cast<VectorType>(BCI.getSrcTy());
+  auto *DstVT = dyn_cast<FixedVectorType>(BCI.getDestTy());
+  auto *SrcVT = dyn_cast<FixedVectorType>(BCI.getSrcTy());
   if (!DstVT || !SrcVT)
     return false;
 
-  unsigned DstNumElems = cast<FixedVectorType>(DstVT)->getNumElements();
-  unsigned SrcNumElems = cast<FixedVectorType>(SrcVT)->getNumElements();
+  unsigned DstNumElems = DstVT->getNumElements();
+  unsigned SrcNumElems = SrcVT->getNumElements();
   IRBuilder<> Builder(&BCI);
   Scatterer Op0 = scatter(&BCI, BCI.getOperand(0));
   ValueVector Res;
@@ -796,11 +796,11 @@
 }
 
 bool ScalarizerVisitor::visitInsertElementInst(InsertElementInst &IEI) {
-  VectorType *VT = dyn_cast<VectorType>(IEI.getType());
+  auto *VT = dyn_cast<FixedVectorType>(IEI.getType());
   if (!VT)
     return false;
 
-  unsigned NumElems = cast<FixedVectorType>(VT)->getNumElements();
+  unsigned NumElems = VT->getNumElements();
   IRBuilder<> Builder(&IEI);
   Scatterer Op0 = scatter(&IEI, IEI.getOperand(0));
   Value *NewElt = IEI.getOperand(1);
@@ -831,11 +831,11 @@
 }
 
 bool ScalarizerVisitor::visitExtractElementInst(ExtractElementInst &EEI) {
-  VectorType *VT = dyn_cast<VectorType>(EEI.getOperand(0)->getType());
+  auto *VT = dyn_cast<FixedVectorType>(EEI.getOperand(0)->getType());
   if (!VT)
     return false;
 
-  unsigned NumSrcElems = cast<FixedVectorType>(VT)->getNumElements();
+  unsigned NumSrcElems = VT->getNumElements();
   IRBuilder<> Builder(&EEI);
   Scatterer Op0 = scatter(&EEI, EEI.getOperand(0));
   Value *ExtIdx = EEI.getOperand(1);
@@ -863,11 +863,11 @@
 }
 
 bool ScalarizerVisitor::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
-  VectorType *VT = dyn_cast<VectorType>(SVI.getType());
+  auto *VT = dyn_cast<FixedVectorType>(SVI.getType());
   if (!VT)
     return false;
 
-  unsigned NumElems = cast<FixedVectorType>(VT)->getNumElements();
+  unsigned NumElems = VT->getNumElements();
   Scatterer Op0 = scatter(&SVI, SVI.getOperand(0));
   Scatterer Op1 = scatter(&SVI, SVI.getOperand(1));
   ValueVector Res;
@@ -887,7 +887,7 @@
 }
 
 bool ScalarizerVisitor::visitPHINode(PHINode &PHI) {
-  VectorType *VT = dyn_cast<VectorType>(PHI.getType());
+  auto *VT = dyn_cast<FixedVectorType>(PHI.getType());
   if (!VT)
     return false;
 
@@ -982,9 +982,9 @@
       // The value is still needed, so recreate it using a series of
       // InsertElements.
       Value *Res = PoisonValue::get(Op->getType());
-      if (auto *Ty = dyn_cast<VectorType>(Op->getType())) {
+      if (auto *Ty = dyn_cast<FixedVectorType>(Op->getType())) {
         BasicBlock *BB = Op->getParent();
-        unsigned Count = cast<FixedVectorType>(Ty)->getNumElements();
+        unsigned Count = Ty->getNumElements();
         IRBuilder<> Builder(Op);
         if (isa<PHINode>(Op))
           Builder.SetInsertPoint(BB, BB->getFirstInsertionPt());
diff --git a/llvm/test/Transforms/Scalarizer/ignore-scalable-vectors.ll b/llvm/test/Transforms/Scalarizer/ignore-scalable-vectors.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/Scalarizer/ignore-scalable-vectors.ll
@@ -0,0 +1,11 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt %s -passes=scalarizer -S -o - | FileCheck %s
+
+define <vscale x 1 x i32> @test1(<vscale x 1 x i32> %a, <vscale x 1 x i32> %b) {
+; CHECK-LABEL: @test1(
+; CHECK-NEXT:    [[R:%.*]] = add <vscale x 1 x i32> [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT:    ret <vscale x 1 x i32> [[R]]
+;
+  %r = add <vscale x 1 x i32> %a, %b
+  ret <vscale x 1 x i32> %r
+}