[llvm] [VPlan] Introduce VPSingleDefRecipe. (PR #77023)

[via llvm-commits]

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@@ -819,10 +810,77 @@ class VPRecipeBase : public ilist_node_with_parent<VPRecipeBase, VPBasicBlock>,
   }                                                                            \
   static inline bool classof(const VPRecipeBase *R) {                          \
     return R->getVPDefID() == VPDefID;                                         \
+  }                                                                            \
+  static inline bool classof(const VPSingleDefRecipe *R) {                     \
+    return R->getVPDefID() == VPDefID;                                         \
   }
 
+/// A common base class for recipes defining a single result value.
+class VPSingleDefRecipe : public VPRecipeBase, public VPValue {
+public:
+  template <typename IterT>
+  VPSingleDefRecipe(const unsigned char SC, IterT Operands, DebugLoc DL = {})
+      : VPRecipeBase(SC, Operands, DL), VPValue(this) {}
+
+  VPSingleDefRecipe(const unsigned char SC, ArrayRef<VPValue *> Operands,
+                    DebugLoc DL = {})
+      : VPRecipeBase(SC, Operands, DL), VPValue(this) {}
+
+  template <typename IterT>
+  VPSingleDefRecipe(const unsigned char SC, IterT Operands, Value *UV,
+                    DebugLoc DL = {})
+      : VPRecipeBase(SC, Operands, DL), VPValue(this, UV) {}
+
+  static inline bool classof(const VPRecipeBase *R) {
+    switch (R->getVPDefID()) {
+    case VPRecipeBase::VPDerivedIVSC:
+    case VPRecipeBase::VPExpandSCEVSC:
+    case VPRecipeBase::VPInstructionSC:
+    case VPRecipeBase::VPReductionSC:
+    case VPRecipeBase::VPReplicateSC:
+    case VPRecipeBase::VPScalarIVStepsSC:
+    case VPRecipeBase::VPVectorPointerSC:
+    case VPRecipeBase::VPWidenCallSC:
+    case VPRecipeBase::VPWidenCanonicalIVSC:
+    case VPRecipeBase::VPWidenCastSC:
+    case VPRecipeBase::VPWidenGEPSC:
+    case VPRecipeBase::VPWidenSC:
+    case VPRecipeBase::VPWidenSelectSC:
+    case VPRecipeBase::VPBlendSC:
+    case VPRecipeBase::VPPredInstPHISC:
+    case VPRecipeBase::VPCanonicalIVPHISC:
+    case VPRecipeBase::VPActiveLaneMaskPHISC:
+    case VPRecipeBase::VPFirstOrderRecurrencePHISC:
+    case VPRecipeBase::VPWidenPHISC:
+    case VPRecipeBase::VPWidenIntOrFpInductionSC:
+    case VPRecipeBase::VPWidenPointerInductionSC:
+    case VPRecipeBase::VPReductionPHISC:
+      return true;
+    case VPRecipeBase::VPInterleaveSC:
+    case VPRecipeBase::VPBranchOnMaskSC:
+    case VPRecipeBase::VPWidenMemoryInstructionSC:
+      return false;
+    }
+    llvm_unreachable("Unhandled VPDefID");
+  }
+
+  static inline bool classof(const VPUser *U) {
+    auto *R = dyn_cast<VPRecipeBase>(U);
+    return R && classof(R);
+  }
+
+  /// Returns the underlying instruction, if the recipe is a VPValue or nullptr
+  /// otherwise.
----------------
ayalz wrote:

Above comment deserves an update - recipe is a VPValue.
(does it really return nullptr otherwise?)

https://github.com/llvm/llvm-project/pull/77023