[llvm] [LV, VPlan] Check if plan is compatible to EVL transform (PR #92092)

[Florian Hahn via llvm-commits]

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@@ -104,7 +104,8 @@ struct VPlanTransforms {
   /// VPCanonicalIVPHIRecipe with a VPEVLBasedIVPHIRecipe.
   /// VPCanonicalIVPHIRecipe is only used to control the loop after
   /// this transformation.
-  static void addExplicitVectorLength(VPlan &Plan);
+  /// \returns true if the transformation succeeds, or false if it doesn't.
+  static bool addExplicitVectorLength(VPlan &Plan);
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fhahn wrote:

nit: `tryAddExplicitVectorLength` would be more accurate now?

https://github.com/llvm/llvm-project/pull/92092