[VPlan] Improve code around WidenPHI's constructor (NFC) (#162277)

Author: artagnon

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -2263,8 +2263,7 @@ class LLVM_ABI_FOR_TEST VPWidenPHIRecipe : public VPSingleDefRecipe,
   /// debug location \p DL.
   VPWidenPHIRecipe(PHINode *Phi, VPValue *Start = nullptr,
                    DebugLoc DL = DebugLoc::getUnknown(), const Twine &Name = "")
-      : VPSingleDefRecipe(VPDef::VPWidenPHISC, ArrayRef<VPValue *>(), Phi, DL),
-        Name(Name.str()) {
+      : VPSingleDefRecipe(VPDef::VPWidenPHISC, {}, Phi, DL), Name(Name.str()) {
     if (Start)
       addOperand(Start);
   }

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -3180,9 +3180,8 @@ expandVPWidenIntOrFpInduction(VPWidenIntOrFpInductionRecipe *WidenIVR,
                               DebugLoc::getUnknown(), "induction");
 
   // Create the widened phi of the vector IV.
-  auto *WidePHI = new VPWidenPHIRecipe(WidenIVR->getPHINode(), nullptr,
+  auto *WidePHI = new VPWidenPHIRecipe(WidenIVR->getPHINode(), Init,
                                        WidenIVR->getDebugLoc(), "vec.ind");
-  WidePHI->addOperand(Init);
   WidePHI->insertBefore(WidenIVR);
 
   // Create the backedge value for the vector IV.