[VPlan] Mark getUnrollPart argument as const (NFC).

Author: fhahn

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -906,10 +906,10 @@ template <unsigned PartOpIdx> class LLVM_ABI_FOR_TEST VPUnrollPartAccessor {
 protected:
   /// Return the VPValue operand containing the unroll part or null if there is
   /// no such operand.
-  VPValue *getUnrollPartOperand(VPUser &U) const;
+  VPValue *getUnrollPartOperand(const VPUser &U) const;
 
   /// Return the unroll part.
-  unsigned getUnrollPart(VPUser &U) const;
+  unsigned getUnrollPart(const VPUser &U) const;
 };
 
 /// Helper to manage IR metadata for recipes. It filters out metadata that
@@ -3486,7 +3486,7 @@ class LLVM_ABI_FOR_TEST VPScalarIVStepsRecipe : public VPRecipeWithIRFlags,
 
   /// Return true if this VPScalarIVStepsRecipe corresponds to part 0. Note that
   /// this is only accurate after the VPlan has been unrolled.
-  bool isPart0() { return getUnrollPart(*this) == 0; }
+  bool isPart0() const { return getUnrollPart(*this) == 0; }
 
   VP_CLASSOF_IMPL(VPDef::VPScalarIVStepsSC)
 

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -413,14 +413,14 @@ void VPSingleDefRecipe::dump() const { VPDef::dump(); }
 
 template <unsigned PartOpIdx>
 VPValue *
-VPUnrollPartAccessor<PartOpIdx>::getUnrollPartOperand(VPUser &U) const {
+VPUnrollPartAccessor<PartOpIdx>::getUnrollPartOperand(const VPUser &U) const {
   if (U.getNumOperands() == PartOpIdx + 1)
     return U.getOperand(PartOpIdx);
   return nullptr;
 }
 
 template <unsigned PartOpIdx>
-unsigned VPUnrollPartAccessor<PartOpIdx>::getUnrollPart(VPUser &U) const {
+unsigned VPUnrollPartAccessor<PartOpIdx>::getUnrollPart(const VPUser &U) const {
   if (auto *UnrollPartOp = getUnrollPartOperand(U))
     return cast<ConstantInt>(UnrollPartOp->getLiveInIRValue())->getZExtValue();
   return 0;