[llvm] [VPlan] Add initial VPScalarEvolution, use to get trip count SCEV (NFC) (PR #94464)

[via llvm-commits]

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@@ -26,6 +26,8 @@ struct VPWidenSelectRecipe;
 class VPReplicateRecipe;
 class VPRecipeBase;
 class VPlan;
+class SCEV;
+class ScalarEvolution;
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ayalz wrote:

nit: better placed above between LLVMContext and VPValue, along with Type.

https://github.com/llvm/llvm-project/pull/94464