Address review comments

Author: preames

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp

@@ -430,13 +430,14 @@ costShuffleViaVRegSplitting(RISCVTTIImpl &TTI, MVT LegalVT,
   copy(Mask, NormalizedMask.begin());
   InstructionCost Cost = 0;
   int NumShuffles = 0;
-  DenseSet<std::pair<ArrayRef<int>, unsigned>> ReusedSingleSrcShuffles;
+  SmallDenseSet<std::pair<ArrayRef<int>, unsigned>> ReusedSingleSrcShuffles;
   processShuffleMasks(
       NormalizedMask, NumOfSrcRegs, NumOfDestRegs, NumOfDestRegs, []() {},
       [&](ArrayRef<int> RegMask, unsigned SrcReg, unsigned DestReg) {
         if (ShuffleVectorInst::isIdentityMask(RegMask, RegMask.size()))
           return;
-        if (!ReusedSingleSrcShuffles.insert(std::make_pair(RegMask, SrcReg)).second)
+        if (!ReusedSingleSrcShuffles.insert(std::make_pair(RegMask, SrcReg))
+                 .second)
           return;
         ++NumShuffles;
         Cost += TTI.getShuffleCost(TTI::SK_PermuteSingleSrc, SingleOpTy,