[VPlan] Simplify addCanonicalIVRecipes by using VPBuilder (NFC).

Use VPBuilder to construct VPInstructions, which means there's no need
to manually inserting recipes.

Author: fhahn

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -8510,21 +8510,16 @@ static void addCanonicalIVRecipes(VPlan &Plan, Type *IdxTy, bool HasNUW,
   VPBasicBlock *Header = TopRegion->getEntryBasicBlock();
   Header->insert(CanonicalIVPHI, Header->begin());
 
-  // Add a CanonicalIVIncrement{NUW} VPInstruction to increment the scalar
-  // IV by VF * UF.
-  auto *CanonicalIVIncrement =
-      new VPInstruction(Instruction::Add, {CanonicalIVPHI, &Plan.getVFxUF()},
-                        {HasNUW, false}, DL, "index.next");
+  VPBuilder Builder(TopRegion->getExitingBasicBlock());
+  // Add a VPInstruction to increment the scalar canonical IV by VF * UF.
+  auto *CanonicalIVIncrement = Builder.createOverflowingOp(
+      Instruction::Add, {CanonicalIVPHI, &Plan.getVFxUF()}, {HasNUW, false}, DL,
+      "index.next");
   CanonicalIVPHI->addOperand(CanonicalIVIncrement);
 
-  VPBasicBlock *EB = TopRegion->getExitingBasicBlock();
-  EB->appendRecipe(CanonicalIVIncrement);
-
   // Add the BranchOnCount VPInstruction to the latch.
-  VPInstruction *BranchBack =
-      new VPInstruction(VPInstruction::BranchOnCount,
-                        {CanonicalIVIncrement, &Plan.getVectorTripCount()}, DL);
-  EB->appendRecipe(BranchBack);
+  Builder.createNaryOp(VPInstruction::BranchOnCount,
+                       {CanonicalIVIncrement, &Plan.getVectorTripCount()}, DL);
 }
 
 // Add exit values to \p Plan. VPLiveOuts are added for each LCSSA phi in the