[llvm] [VPlan] Introduce VPInstructionWithType, use instead of VPScalarCast(NFC) (PR #129706)

[Florian Hahn via llvm-commits]

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@@ -1025,6 +1024,55 @@ class VPInstruction : public VPRecipeWithIRFlags,
   StringRef getName() const { return Name; }
 };
 
+/// A specialization of VPInstruction augmenting it with a dedicated result
+/// type, to be used when the opcode and operands of the VPInstruction don't
+/// directly determine the result type.
+class VPInstructionWithType : public VPInstruction {
+  /// Scalar result type produced by the recipe.
+  Type *ResultTy;
+
+  Value *generate(VPTransformState &State);
+
+public:
+  VPInstructionWithType(unsigned Opcode, ArrayRef<VPValue *> Operands,
+                        Type *ResultTy, DebugLoc DL, const Twine &Name = "")
+      : VPInstruction(Opcode, Operands, DL, Name), ResultTy(ResultTy) {}
+
+  static inline bool classof(const VPRecipeBase *R) {
+    auto *VPI = dyn_cast<VPInstruction>(R);
+    return VPI && Instruction::isCast(VPI->getOpcode());
+  }
+
+  static inline bool classof(const VPUser *R) {
+    return isa<VPInstructionWithType>(cast<VPRecipeBase>(R));
+  }
+
+  VPInstruction *clone() override {
+    auto *New =
+        new VPInstructionWithType(getOpcode(), {getOperand(0)}, getResultType(),
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fhahn wrote:

For now yes, but removed restriction, thanks!

https://github.com/llvm/llvm-project/pull/129706