[VPlan] Add createPtrAdd helper (NFC).

Preparation for llvm#106431.

Author: fhahn

llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h

@@ -220,6 +220,11 @@ class VPBuilder {
         new VPInstruction(Instruction::ICmp, Pred, A, B, DL, Name));
   }
 
+  VPInstruction *createPtrAdd(VPValue *Ptr, VPValue *Offset, DebugLoc DL,
+                              const Twine &Name = "") {
+    return createInstruction(VPInstruction::PtrAdd, {Ptr, Offset}, DL, Name);
+  }
+
   VPDerivedIVRecipe *createDerivedIV(InductionDescriptor::InductionKind Kind,
                                      FPMathOperator *FPBinOp, VPValue *Start,
                                      VPCanonicalIVPHIRecipe *CanonicalIV,

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -593,12 +593,10 @@ static void legalizeAndOptimizeInductions(VPlan &Plan) {
           Plan, InductionDescriptor::IK_IntInduction, Instruction::Add, nullptr,
           nullptr, StartV, StepV, Builder);
 
-      auto *Recipe = new VPInstruction(VPInstruction::PtrAdd,
-                                       {PtrIV->getStartValue(), Steps},
-                                       PtrIV->getDebugLoc(), "next.gep");
+      VPValue *PtrAdd = Builder.createPtrAdd(PtrIV->getStartValue(), Steps,
+                                             PtrIV->getDebugLoc(), "next.gep");
 
-      Recipe->insertAfter(Steps);
-      PtrIV->replaceAllUsesWith(Recipe);
+      PtrIV->replaceAllUsesWith(PtrAdd);
       continue;
     }