[VPlan] Use VPBuilder to create ActiveLaneMask (NFC).

Author: fhahn

llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h

@@ -79,6 +79,13 @@ class VPBuilder {
   VPBasicBlock *getInsertBlock() const { return BB; }
   VPBasicBlock::iterator getInsertPoint() const { return InsertPt; }
 
+  /// Create a VPBuilder to insert after \p R.
+  static VPBuilder getToInsertAfter(VPRecipeBase *R) {
+    VPBuilder B;
+    B.setInsertPoint(R->getParent(), std::next(R->getIterator()));
+    return B;
+  }
+
   /// InsertPoint - A saved insertion point.
   class VPInsertPoint {
     VPBasicBlock *Block = nullptr;
@@ -131,17 +138,18 @@ class VPBuilder {
 
   /// Create an N-ary operation with \p Opcode, \p Operands and set \p Inst as
   /// its underlying Instruction.
-  VPValue *createNaryOp(unsigned Opcode, ArrayRef<VPValue *> Operands,
-                        Instruction *Inst = nullptr, const Twine &Name = "") {
+  VPInstruction *createNaryOp(unsigned Opcode, ArrayRef<VPValue *> Operands,
+                              Instruction *Inst = nullptr,
+                              const Twine &Name = "") {
     DebugLoc DL;
     if (Inst)
       DL = Inst->getDebugLoc();
     VPInstruction *NewVPInst = createInstruction(Opcode, Operands, DL, Name);
     NewVPInst->setUnderlyingValue(Inst);
     return NewVPInst;
   }
-  VPValue *createNaryOp(unsigned Opcode, ArrayRef<VPValue *> Operands,
-                        DebugLoc DL, const Twine &Name = "") {
+  VPInstruction *createNaryOp(unsigned Opcode, ArrayRef<VPValue *> Operands,
+                              DebugLoc DL, const Twine &Name = "") {
     return createInstruction(Opcode, Operands, DL, Name);
   }
 

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -1192,10 +1192,10 @@ void VPlanTransforms::addActiveLaneMask(
     LaneMask = addVPLaneMaskPhiAndUpdateExitBranch(
         Plan, DataAndControlFlowWithoutRuntimeCheck);
   } else {
-    LaneMask = new VPInstruction(VPInstruction::ActiveLaneMask,
-                                 {WideCanonicalIV, Plan.getTripCount()},
-                                 nullptr, "active.lane.mask");
-    LaneMask->insertAfter(WideCanonicalIV);
+    VPBuilder B = VPBuilder::getToInsertAfter(WideCanonicalIV);
+    LaneMask = B.createNaryOp(VPInstruction::ActiveLaneMask,
+                              {WideCanonicalIV, Plan.getTripCount()}, nullptr,
+                              "active.lane.mask");
   }
 
   // Walk users of WideCanonicalIV and replace all compares of the form