[llvm] [VPlan] Update getBestPlan to return VF, use also for epilogue vec. (PR #98821)

[via llvm-commits]

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@@ -7178,12 +7177,10 @@ VPlan &LoopVectorizationPlanner::getBestPlan() const {
       VectorizationFactor CurrentFactor(VF, Cost, ScalarCost);
       if (isMoreProfitable(CurrentFactor, BestFactor)) {
         BestFactor = CurrentFactor;
-        BestPlan = &*P;
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ayalz wrote:

nit: can now also drop the {}

https://github.com/llvm/llvm-project/pull/98821