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

[Luke Lau via llvm-commits]

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@@ -2361,6 +2423,164 @@ 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;
+
+  /// For cloning VPExtendedReductionRecipe.
+  VPExtendedReductionRecipe(VPExtendedReductionRecipe *ExtRed)
+      : VPReductionRecipe(
+            VPDef::VPExtendedReductionSC, ExtRed->getRecurrenceDescriptor(),
+            nullptr, {ExtRed->getChainOp(), ExtRed->getVecOp()},
+            ExtRed->getCondOp(), ExtRed->isOrdered(), ExtRed->getDebugLoc()),
+        ExtOp(ExtRed->getExtOpcode()) {}
+
+public:
+  VPExtendedReductionRecipe(VPReductionRecipe *R, VPWidenCastRecipe *Ext)
+      : VPReductionRecipe(
+            VPDef::VPExtendedReductionSC, R->getRecurrenceDescriptor(),
+            {R->getChainOp(), Ext->getOperand(0)}, R->getCondOp(),
+            R->isOrdered(), NonNegFlagsTy(Ext->isNonNeg()), Ext->getDebugLoc()),
+        ExtOp(Ext->getOpcode()) {}
+
+  ~VPExtendedReductionRecipe() override = default;
+
+  VPExtendedReductionRecipe *clone() override {
+    auto *Copy = new VPExtendedReductionRecipe(this);
+    Copy->transferFlags(*this);
+    return Copy;
+  }
+
+  VP_CLASSOF_IMPL(VPDef::VPExtendedReductionSC);
+
+  void execute(VPTransformState &State) override {
+    llvm_unreachable("VPExtendedReductionRecipe should be transform to "
+                     "VPExtendedRecipe + VPReductionRecipe before execution.");
+  };
+
+  /// Return the cost of VPExtendedReductionRecipe.
+  InstructionCost computeCost(ElementCount VF,
+                              VPCostContext &Ctx) const override;
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+  /// Print the recipe.
+  void print(raw_ostream &O, const Twine &Indent,
+             VPSlotTracker &SlotTracker) const override;
+#endif
+
+  /// The scalar type after extended.
+  Type *getResultType() const {
+    return getRecurrenceDescriptor().getRecurrenceType();
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lukel97 wrote:

Actually I think if #131300 lands then you'll need to store the recurrence type separately. But that doesn't seem too bad.

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