apply comment

Author: HanKuanChen

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -9616,16 +9616,16 @@ void BoUpSLP::reorderGatherNode(TreeEntry &TE) {
     Cost += ::getShuffleCost(*TTI, TTI::SK_InsertSubvector, VecTy, {}, CostKind,
                              Idx, getWidenedType(ScalarTy, Sz));
   }
-  if (isa<FixedVectorType>(ScalarTy)) {
+  if (auto *FTy = dyn_cast<FixedVectorType>(ScalarTy)) {
     assert(SLPReVec && "Only supported by REVEC.");
     // If ScalarTy is FixedVectorType, we should use CreateInsertVector instead
     // of CreateInsertElement.
     unsigned ScalarTyNumElements = getNumElements(ScalarTy);
     for (unsigned I : seq<unsigned>(TE.Scalars.size()))
       if (DemandedElts[I])
-        Cost += TTI->getShuffleCost(
-            TTI::SK_InsertSubvector, VecTy, std::nullopt, CostKind,
-            I * ScalarTyNumElements, cast<FixedVectorType>(ScalarTy));
+        Cost +=
+            TTI->getShuffleCost(TTI::SK_InsertSubvector, VecTy, std::nullopt,
+                                CostKind, I * ScalarTyNumElements, FTy);
   } else {
     Cost += TTI->getScalarizationOverhead(VecTy, DemandedElts, /*Insert=*/true,
                                           /*Extract=*/false, CostKind);