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

[Florian Hahn via llvm-commits]

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@@ -2403,6 +2478,168 @@ class VPReductionEVLRecipe : public VPReductionRecipe {
   }
 };
 
+/// A recipe to represent inloop extended reduction operations, performing a
+/// reduction on a extended vector operand into a scalar value, and adding the
+/// result to a chain. This recipe is abstract and needs to be lowered to
+/// concrete recipes before codegen. The Operands are {ChainOp, VecOp,
+/// [Condition]}.
+class VPExtendedReductionRecipe : public VPReductionRecipe {
+  /// Opcode of the extend recipe will be lowered to.
+  Instruction::CastOps ExtOp;
+
+public:
+  VPExtendedReductionRecipe(VPReductionRecipe *R, VPWidenCastRecipe *Ext)
+      : VPReductionRecipe(VPDef::VPExtendedReductionSC,
+                          R->getRecurrenceDescriptor(),
+                          {R->getChainOp(), Ext->getOperand(0)}, R->getCondOp(),
+                          R->isOrdered(), Ext->isNonNeg(), Ext->getDebugLoc()),
+        ExtOp(Ext->getOpcode()) {}
+
+  /// For cloning VPExtendedReductionRecipe.
+  VPExtendedReductionRecipe(VPExtendedReductionRecipe *ExtRed)
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fhahn wrote:

should be private?

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