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

[Florian Hahn via llvm-commits]

================
@@ -2653,6 +2657,210 @@ 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 {
+  /// Type after extend.
+  Type *ResultTy;
+  CastInst *ExtInstr;
+
+protected:
+  VPExtendedReductionRecipe(const unsigned char SC,
+                            const RecurrenceDescriptor &R, Instruction *RedI,
+                            Instruction::CastOps ExtOp, CastInst *ExtInstr,
+                            VPValue *ChainOp, VPValue *VecOp, VPValue *CondOp,
+                            bool IsOrdered, Type *ResultTy)
+      : VPReductionRecipe(SC, R, RedI, ArrayRef<VPValue *>({ChainOp, VecOp}),
+                          CondOp, IsOrdered),
+        ResultTy(ResultTy), ExtInstr(ExtInstr) {}
+
+public:
+  VPExtendedReductionRecipe(const RecurrenceDescriptor &R, Instruction *RedI,
+                            VPValue *ChainOp, VPWidenCastRecipe *Ext,
+                            VPValue *CondOp, bool IsOrdered)
+      : VPExtendedReductionRecipe(
+            VPDef::VPExtendedReductionSC, R, RedI, Ext->getOpcode(),
+            cast<CastInst>(Ext->getUnderlyingInstr()), ChainOp,
+            Ext->getOperand(0), CondOp, IsOrdered, Ext->getResultType()) {}
+
+  ~VPExtendedReductionRecipe() override = default;
+
+  VPExtendedReductionRecipe *clone() override {
+    llvm_unreachable("Not implement yet");
+  }
+
+  static inline bool classof(const VPRecipeBase *R) {
+    return R->getVPDefID() == VPDef::VPExtendedReductionSC;
+  }
+
+  static inline bool classof(const VPUser *U) {
+    auto *R = dyn_cast<VPRecipeBase>(U);
+    return R && classof(R);
+  }
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fhahn wrote:

Can `VP_CLASSOF_IMPL` be used?

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