[llvm] [VPlan] Impl VPlan-based pattern match for ExtendedRed and MulAccRed (NFCI) (PR #113903)

[Alexey Bataev via llvm-commits]

================
@@ -9387,6 +9330,171 @@ VPlanPtr LoopVectorizationPlanner::buildVPlan(VFRange &Range) {
   return Plan;
 }
 
+/// Try to match the extended-reduction and create VPExtendedReductionRecipe.
+///
+/// This function try to match following pattern which will generate
+/// extended-reduction instruction.
+///    reduce(ext(...)).
+static VPExtendedReductionRecipe *tryToMatchAndCreateExtendedReduction(
+    const RecurrenceDescriptor &RdxDesc, Instruction *CurrentLinkI,
+    VPValue *PreviousLink, VPValue *VecOp, VPValue *CondOp,
+    LoopVectorizationCostModel &CM, VPCostContext &Ctx, VFRange &Range) {
+  using namespace VPlanPatternMatch;
+
+  VPValue *A;
+  Type *RedTy = RdxDesc.getRecurrenceType();
+
+  // Test if using extended-reduction is beneficial and clamp the range.
+  auto IsExtendedRedValidAndClampRange = [&](unsigned Opcode, bool isZExt,
+                                             Type *SrcTy) -> bool {
+    return LoopVectorizationPlanner::getDecisionAndClampRange(
+        [&](ElementCount VF) {
+          VectorType *SrcVecTy = cast<VectorType>(ToVectorTy(SrcTy, VF));
+          VectorType *VectorTy = cast<VectorType>(ToVectorTy(RedTy, VF));
----------------
alexey-bataev wrote:

```suggestion
          auto *SrcVecTy = cast<VectorType>(ToVectorTy(SrcTy, VF));
          auto *VectorTy = cast<VectorType>(ToVectorTy(RedTy, VF));
```

https://github.com/llvm/llvm-project/pull/113903