[llvm] [VPlan] Add VPValue for VF, use it for VPWidenIntOrFpInductionRecipe. (PR #95305)

[via llvm-commits]

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@@ -3282,6 +3287,8 @@ class VPlan {
   /// Represents the vector trip count.
   VPValue VectorTripCount;
 
+  VPValue VF;
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ayalz wrote:

(This is a follow-up thought, hence originally in brackets)
Regions (and blocks in general) currently model the HCFG only, leaving the def-use graph of values to recipes. A loop region has a canonical IV recipe which typically uses VFxUF as the canonical step controlling the loop. The latter could be a Mul recipe whose operands provide VF and UF, and a loop region could provide getVF() and getUF() to ease their retrieval?

https://github.com/llvm/llvm-project/pull/95305