!fixup address latest comments, thanks

Author: fhahn

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -2381,7 +2381,6 @@ void InnerLoopVectorizer::introduceCheckBlockInVPlan(BasicBlock *CheckIRBB) {
   // We just connected a new block to the scalar preheader. Update all
   // VPPhis by adding an incoming value for it, replicating the last value.
   unsigned NumPredecessors = ScalarPH->getNumPredecessors();
-  (void)NumPredecessors;
   for (VPRecipeBase &R : cast<VPBasicBlock>(ScalarPH)->phis()) {
     assert(isa<VPPhi>(&R) && "Phi expected to be VPPhi");
     assert(cast<VPPhi>(&R)->getNumIncoming() == NumPredecessors - 1 &&

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -3530,17 +3530,16 @@ class VPScalarIVStepsRecipe : public VPRecipeWithIRFlags,
 
 /// Casting from VPRecipeBase -> VPPhiAccessors is supported for all recipe
 /// types implementing VPPhiAccessors. Used by isa<> & co.
-template <typename SrcTy> struct CastIsPossible<VPPhiAccessors, SrcTy> {
-  static inline bool isPossible(SrcTy f) {
+template <> struct CastIsPossible<VPPhiAccessors, const VPRecipeBase *> {
+  static inline bool isPossible(const VPRecipeBase *f) {
     // TODO: include VPPredInstPHIRecipe too, once it implements VPPhiAccessors.
     return isa<VPIRPhi, VPHeaderPHIRecipe, VPWidenPHIRecipe, VPPhi>(f);
   }
 };
 /// Support casting from VPRecipeBase -> VPPhiAccessors, by down-casting to the
 /// recipe types implementing VPPhiAccessors. Used by cast<>, dyn_cast<> & co.
 template <typename SrcTy>
-struct CastInfo<VPPhiAccessors, SrcTy>
-    : public CastIsPossible<VPPhiAccessors, SrcTy> {
+struct CastInfoVPPhiAccessors : public CastIsPossible<VPPhiAccessors, SrcTy> {
 
   using Self = CastInfo<VPPhiAccessors, SrcTy>;
 
@@ -3567,6 +3566,12 @@ struct CastInfo<VPPhiAccessors, SrcTy>
     return doCast(f);
   }
 };
+template <>
+struct CastInfo<VPPhiAccessors, VPRecipeBase *>
+    : CastInfoVPPhiAccessors<VPRecipeBase *> {};
+template <>
+struct CastInfo<VPPhiAccessors, const VPRecipeBase *>
+    : CastInfoVPPhiAccessors<const VPRecipeBase *> {};
 
 /// VPBasicBlock serves as the leaf of the Hierarchical Control-Flow Graph. It
 /// holds a sequence of zero or more VPRecipe's each representing a sequence of

llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp

@@ -548,7 +548,7 @@ void VPlanTransforms::prepareForVectorization(
 
   assert(MiddleVPBB->getNumSuccessors() == 2 && "must have 2 successors");
 
-  // Add a check in the middle block to see if we have completed$ all of the
+  // Add a check in the middle block to see if we have completed all of the
   // iterations in the first vector loop.
   //
   // Three cases:

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -1191,7 +1191,6 @@ void VPPhiAccessors::removeIncomingValueFor(VPBlockBase *IncomingBlock) const {
   assert(R->getNumOperands() == Preds.size() &&
          "Number of phi operands must match number of predecessors");
   unsigned Position = std::distance(Preds.begin(), find(Preds, IncomingBlock));
-  R->getOperand(Position)->removeUser(*R);
   R->removeOperand(Position);
 }
 

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -1867,10 +1867,8 @@ static void removeBranchOnConst(VPlan &Plan) {
            "There must be a single edge between VPBB and its successor");
     // Values coming from VPBB into phi recipes of RemoveSucc are removed from
     // these recipes.
-    for (VPRecipeBase &R : make_early_inc_range(*RemovedSucc)) {
-      auto *Phi = dyn_cast<VPPhiAccessors>(&R);
-      if (!Phi)
-        break;
+    for (VPRecipeBase &R : RemovedSucc->phis()) {
+      auto *Phi = cast<VPPhiAccessors>(&R);
       assert((!isa<VPIRPhi>(&R) || RemovedSucc->getNumPredecessors() == 1) &&
              "VPIRPhis must have a single predecessor");
       Phi->removeIncomingValueFor(VPBB);

llvm/lib/Transforms/Vectorize/VPlanValue.h

@@ -205,7 +205,12 @@ class VPUser {
 
   SmallVector<VPValue *, 2> Operands;
 
-  void removeOperand(unsigned Idx) { Operands.erase(Operands.begin() + Idx); }
+  /// Removes the operand at index \p Idx. This also removes the VPUser from the
+  /// use-list of the operand.
+  void removeOperand(unsigned Idx) {
+    getOperand(Idx)->removeUser(*this);
+    Operands.erase(Operands.begin() + Idx);
+  }
 
 protected:
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)