[VPlan] Improve iterator-related code (NFC) (llvm#155834)

Author: artagnon

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -1645,10 +1645,8 @@ class LLVM_ABI_FOR_TEST VPWidenCallRecipe : public VPRecipeWithIRFlags,
     return cast<Function>(getOperand(getNumOperands() - 1)->getLiveInIRValue());
   }
 
-  operand_range args() { return make_range(op_begin(), std::prev(op_end())); }
-  const_operand_range args() const {
-    return make_range(op_begin(), std::prev(op_end()));
-  }
+  operand_range args() { return drop_end(operands()); }
+  const_operand_range args() const { return drop_end(operands()); }
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
   /// Print the recipe.
@@ -2382,9 +2380,8 @@ class LLVM_ABI_FOR_TEST VPBlendRecipe : public VPSingleDefRecipe {
   }
 
   VPBlendRecipe *clone() override {
-    SmallVector<VPValue *> Ops(operands());
-    return new VPBlendRecipe(cast_or_null<PHINode>(getUnderlyingValue()), Ops,
-                             getDebugLoc());
+    return new VPBlendRecipe(cast_or_null<PHINode>(getUnderlyingValue()),
+                             operands(), getDebugLoc());
   }
 
   VP_CLASSOF_IMPL(VPDef::VPBlendSC)
@@ -4143,7 +4140,7 @@ class VPlan {
   /// Returns an iterator range over all VFs of the plan.
   iterator_range<SmallSetVector<ElementCount, 2>::iterator>
   vectorFactors() const {
-    return {VFs.begin(), VFs.end()};
+    return VFs;
   }
 
   bool hasScalarVFOnly() const {