[llvm] [VPlan] Add VPInstruction::StepVector and use it in VPWidenIntOrFpInductionRecipe (PR #129508)

[Florian Hahn via llvm-commits]

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@@ -1063,6 +1065,9 @@ class VPInstructionWithType : public VPInstruction {
       : VPInstruction(Opcode, Operands, FMFs, DL, Name), ResultTy(ResultTy) {}
 
   static inline bool classof(const VPRecipeBase *R) {
+    if (isa<VPInstruction>(R) &&
+        cast<VPInstruction>(R)->getOpcode() == VPInstruction::StepVector)
+      return true;
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fhahn wrote:

merge with the check for WideIVStep, possibly via switch?

https://github.com/llvm/llvm-project/pull/129508