[llvm] [VPlan] Add VPWidenInduction recipe as common base class (NFC). (PR #120008)

[Shih-Po Hung via llvm-commits]

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@@ -2099,38 +2099,81 @@ class VPHeaderPHIRecipe : public VPSingleDefRecipe {
   }
 };
 
+/// Base class for widened induction (VPWidenIntOrFpInductionRecipe and
+/// VPWidenPointerInductionRecipe), providing shared functionality, including
+/// retrieving the step value, induction descriptor and original phi node.
+class VPWidenInductionRecipe : public VPHeaderPHIRecipe {
+  const InductionDescriptor &IndDesc;
+
+public:
+  VPWidenInductionRecipe(unsigned char Kind, PHINode *IV, VPValue *Start,
+                         VPValue *Step, const InductionDescriptor &IndDesc,
+                         DebugLoc DL)
+      : VPHeaderPHIRecipe(Kind, IV, Start, DL), IndDesc(IndDesc) {
+    addOperand(Step);
+  }
+
+  static inline bool classof(const VPRecipeBase *R) {
+    return R->getVPDefID() == VPDef::VPWidenIntOrFpInductionSC ||
+           R->getVPDefID() == VPDef::VPWidenPointerInductionSC;
+  }
+
+  virtual void execute(VPTransformState &State) override = 0;
+
+  /// Returns the step value of the induction.
+  VPValue *getStepValue() { return getOperand(1); }
+  const VPValue *getStepValue() const { return getOperand(1); }
+
+  PHINode *getPHINode() const { return cast<PHINode>(getUnderlyingValue()); }
+
+  /// Returns the induction descriptor for the recipe.
+  const InductionDescriptor &getInductionDescriptor() const { return IndDesc; }
+
+  VPValue *getBackedgeValue() override {
+    // TODO: All operands of base recipe must exist and be at same index in
+    // derived recipe.
+    llvm_unreachable(
+        "VPWidenIntOrFpInductionRecipe generates its own backedge value");
+  }
+
+  VPRecipeBase &getBackedgeRecipe() override {
+    // TODO: All operands of base recipe must exist and be at same index in
+    // derived recipe.
+    llvm_unreachable(
+        "VPWidenIntOrFpInductionRecipe generates its own backedge value");
+  }
+};
+
 /// A recipe for handling phi nodes of integer and floating-point inductions,
 /// producing their vector values.
-class VPWidenIntOrFpInductionRecipe : public VPHeaderPHIRecipe {
-  PHINode *IV;
+class VPWidenIntOrFpInductionRecipe : public VPWidenInductionRecipe {
   TruncInst *Trunc;
-  const InductionDescriptor &IndDesc;
 
 public:
   VPWidenIntOrFpInductionRecipe(PHINode *IV, VPValue *Start, VPValue *Step,
                                 VPValue *VF, const InductionDescriptor &IndDesc,
                                 DebugLoc DL)
-      : VPHeaderPHIRecipe(VPDef::VPWidenIntOrFpInductionSC, IV, Start, DL),
-        IV(IV), Trunc(nullptr), IndDesc(IndDesc) {
-    addOperand(Step);
+      : VPWidenInductionRecipe(VPDef::VPWidenIntOrFpInductionSC, IV, Start,
+                               Step, IndDesc, DL),
+        Trunc(nullptr) {
     addOperand(VF);
   }
 
   VPWidenIntOrFpInductionRecipe(PHINode *IV, VPValue *Start, VPValue *Step,
                                 VPValue *VF, const InductionDescriptor &IndDesc,
                                 TruncInst *Trunc, DebugLoc DL)
-      : VPHeaderPHIRecipe(VPDef::VPWidenIntOrFpInductionSC, Trunc, Start, DL),
-        IV(IV), Trunc(Trunc), IndDesc(IndDesc) {
-    addOperand(Step);
+      : VPWidenInductionRecipe(VPDef::VPWidenIntOrFpInductionSC, IV, Start,
+                               Step, IndDesc, DL),
----------------
arcbbb wrote:

This is not NFC because the underlying instruction changed from Trunc to IV here.

https://github.com/llvm/llvm-project/pull/120008