[llvm] [VPlan] Add opcode to create step for wide inductions. (PR #119284)

[Luke Lau via llvm-commits]

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@@ -865,6 +865,7 @@ class VPInstruction : public VPRecipeWithIRFlags,
     CalculateTripCountMinusVF,
     // Increment the canonical IV separately for each unrolled part.
     CanonicalIVIncrementForPart,
+    WideIVStep,
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lukel97 wrote:

Nit, add a doc comment explaining the operands?

https://github.com/llvm/llvm-project/pull/119284