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

[Florian Hahn via llvm-commits]

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@@ -2694,6 +2724,202 @@ class VPReductionEVLRecipe : public VPReductionRecipe {
   }
 };
 
+/// A recipe to represent inloop extended reduction operations, performing a
+/// reduction on a vector operand into a scalar value, and adding the result to
+/// a chain. This recipe is high level abstract which will generate
+/// VPReductionRecipe and VPWidenCastRecipe before execution. The Operands are
+/// {ChainOp, VecOp, [Condition]}.
+class VPExtendedReductionRecipe : public VPReductionRecipe {
+  Instruction::CastOps ExtOp;
+  DebugLoc ExtDL;
+  /// Non-negative flag for the extended instruction.
+  bool IsNonNeg;
+
+protected:
+  VPExtendedReductionRecipe(const unsigned char SC,
+                            const RecurrenceDescriptor &R, Instruction *RedI,
+                            Instruction::CastOps ExtOp, DebugLoc ExtDL,
+                            bool IsNonNeg, VPValue *ChainOp, VPValue *VecOp,
+                            VPValue *CondOp, bool IsOrdered)
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fhahn wrote:

why do we need the private constructor?

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