[VPlan] Address post-commit for #114305.

Apply suggested renaming and adjust placement as suggested in
https://github.com/llvm/llvm-project/pull/114305. Also drop unneeded
RPOT creation.

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -7677,6 +7677,7 @@ DenseMap<const SCEV *, Value *> LoopVectorizationPlanner::executePlan(
   VPlanTransforms::unrollByUF(BestVPlan, BestUF,
                               OrigLoop->getHeader()->getContext());
   VPlanTransforms::optimizeForVFAndUF(BestVPlan, BestVF, BestUF, PSE);
+  VPlanTransforms::convertToConcreteRecipes(BestVPlan);
 
   // Perform the actual loop transformation.
   VPTransformState State(&TTI, BestVF, BestUF, LI, DT, ILV.Builder, &ILV,
@@ -7740,7 +7741,6 @@ DenseMap<const SCEV *, Value *> LoopVectorizationPlanner::executePlan(
   BestVPlan.prepareToExecute(ILV.getTripCount(),
                              ILV.getOrCreateVectorTripCount(nullptr),
                              CanonicalIVStartValue, State);
-  VPlanTransforms::prepareToExecute(BestVPlan);
 
   BestVPlan.execute(&State);
 

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -3486,7 +3486,7 @@ void VPEVLBasedIVPHIRecipe::print(raw_ostream &O, const Twine &Indent,
 
 void VPScalarPHIRecipe::execute(VPTransformState &State) {
   BasicBlock *VectorPH = State.CFG.getPreheaderBBFor(this);
-  Value *Start = State.get(getOperand(0), VPLane(0));
+  Value *Start = State.get(getStartValue(), VPLane(0));
   PHINode *Phi = State.Builder.CreatePHI(Start->getType(), 2, Name);
   Phi->addIncoming(Start, VectorPH);
   Phi->setDebugLoc(getDebugLoc());

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -1820,9 +1820,7 @@ void VPlanTransforms::createInterleaveGroups(
   }
 }
 
-void VPlanTransforms::prepareToExecute(VPlan &Plan) {
-  ReversePostOrderTraversal<VPBlockDeepTraversalWrapper<VPBlockBase *>> RPOT(
-      Plan.getVectorLoopRegion());
+void VPlanTransforms::convertToConcreteRecipes(VPlan &Plan) {
   for (VPBasicBlock *VPBB : VPBlockUtils::blocksOnly<VPBasicBlock>(
            vp_depth_first_deep(Plan.getEntry()))) {
     for (VPRecipeBase &R : make_early_inc_range(VPBB->phis())) {

llvm/lib/Transforms/Vectorize/VPlanTransforms.h

@@ -125,7 +125,7 @@ struct VPlanTransforms {
   static void removeDeadRecipes(VPlan &Plan);
 
   /// Lower abstract recipes to concrete ones, that can be codegen'd.
-  static void prepareToExecute(VPlan &Plan);
+  static void convertToConcreteRecipes(VPlan &Plan);
 };
 
 } // namespace llvm