[VPlan] Refine comments

Author: artagnon

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -939,8 +939,8 @@ static void recursivelyDeleteDeadRecipes(VPValue *V) {
   }
 }
 
-/// Try to fold \p R using InstSimplifyFolder to a constant. Will succeed and
-/// return a non-nullptr Value for a handled \p Opcode if \p Operands are
+/// Try to fold \p R using InstSimplifyFolder. Will succeed and return a
+/// non-nullptr Value for a handled \p Opcode if corresponding \p Operands are
 /// foldable.
 static Value *tryToConstantFold(const VPRecipeBase &R, unsigned Opcode,
                                 ArrayRef<VPValue *> Operands,
@@ -995,7 +995,8 @@ static Value *tryToConstantFold(const VPRecipeBase &R, unsigned Opcode,
 static void simplifyRecipe(VPRecipeBase &R, VPTypeAnalysis &TypeInfo) {
   using namespace llvm::VPlanPatternMatch;
 
-  // Constant folding.
+  // Simplification of live-in IR values for SingleDef recipes using
+  // InstSimplifyFolder.
   if (TypeSwitch<VPRecipeBase *, bool>(&R)
           .Case<VPInstruction, VPWidenRecipe, VPWidenCastRecipe,
                 VPReplicateRecipe>([&](auto *I) {