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

[via llvm-commits]

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@@ -2099,38 +2099,81 @@ class VPHeaderPHIRecipe : public VPSingleDefRecipe {
   }
 };
 
+/// Base class for widened induction (VPWidenIntOrFpInductionRecipe and
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ayalz wrote:

Independent: perhaps worth handling Int and FP separately?

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