[llvm] [SLP]Allow bitcast/bswap based reductions for types, larger than the total strided size (PR #184018)

[Alexey Bataev via llvm-commits]

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@@ -21634,17 +21648,25 @@ Value *BoUpSLP::vectorizeTree(TreeEntry *E) {
       Const->VectorizedValue = PoisonValue::get(getWidenedType(
           Const->Scalars.front()->getType(), Const->getVectorFactor()));
       Value *Op = vectorizeOperand(ZExt, 0);
+      auto *SrcType = IntegerType::get(
+          Op->getContext(),
+          DL->getTypeSizeInBits(cast<CastInst>(ZExt->getMainOp())->getSrcTy()) *
+              E->getVectorFactor());
+      auto *OrigScalarTy = ScalarTy;
       // Set the scalar type properly to avoid casting to the extending type.
       ScalarTy = cast<CastInst>(ZExt->getMainOp())->getSrcTy();
       Op = FinalShuffle(Op, E);
-      auto *V = Builder.CreateBitCast(
-          Op, IntegerType::get(
-                  Op->getContext(),
-                  DL->getTypeSizeInBits(ZExt->getMainOp()->getType())));
-      if (ShuffleOrOp == TreeEntry::ReducedBitcastBSwap)
+      auto *V = Builder.CreateBitCast(Op, SrcType);
+      ++NumVectorInstructions;
+      if (ShuffleOrOp == TreeEntry::ReducedBitcastBSwap) {
         V = Builder.CreateUnaryIntrinsic(Intrinsic::bswap, V);
+        ++NumVectorInstructions;
+      }
+      if (SrcType != OrigScalarTy) {
+        V = Builder.CreateIntCast(V, OrigScalarTy, /*isSigned=*/false);
+        ++NumVectorInstructions;
+      }
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alexey-bataev wrote:

Missing statistics increment, yes

https://github.com/llvm/llvm-project/pull/184018