[NFC] Factor out function to detect if an attribute has an argument.

[jdoerfert]

LGTM with one small nit

llvm/include/llvm/IR/Attributes.h

114

Nit: iff means if and only if usually, just remove one f

llvm/include/llvm/IR/Attributes.h

static Attribute getWithAllocSizeArgs(LLVMContext &Context,
                                         unsigned ElemSizeArg,
                                         const Optional<unsigned> &NumElemsArg);
   static Attribute getWithByValType(LLVMContext &Context, Type *Ty);
 
   static Attribute::AttrKind getAttrKindFromName(StringRef AttrName);
 
   static StringRef getNameFromAttrKind(Attribute::AttrKind AttrKind);
 
+  /// Return true if and only if the attribute has an Argument.
+  static bool doesAttrKindHaveArgument(Attribute::AttrKind AttrKind);
+
   //===--------------------------------------------------------------------===//
   // Attribute Accessors
   //===--------------------------------------------------------------------===//
 
   /// Return true if the attribute is an Attribute::AttrKind type.
   bool isEnumAttribute() const;
 
   /// Return true if the attribute is an integer attribute.

llvm/lib/IR/AttributeImpl.h

 class IntAttributeImpl : public EnumAttributeImpl {
   uint64_t Val;
 
   void anchor() override;
 
 public:
   IntAttributeImpl(Attribute::AttrKind Kind, uint64_t Val)
       : EnumAttributeImpl(IntAttrEntry, Kind), Val(Val) {
-    assert((Kind == Attribute::Alignment || Kind == Attribute::StackAlignment ||
-            Kind == Attribute::Dereferenceable ||
-            Kind == Attribute::DereferenceableOrNull ||
-            Kind == Attribute::AllocSize) &&
+    assert(Attribute::doesAttrKindHaveArgument(Kind) &&
            "Wrong kind for int attribute!");
   }
 
   uint64_t getValue() const { return Val; }
 };
 
 class StringAttributeImpl : public AttributeImpl {
   virtual void anchor();

llvm/lib/IR/Attributes.cpp

 #include "llvm/IR/Attributes.inc"
   case AttrKind::None:
     return "none";
   default:
     llvm_unreachable("invalid Kind");
   }
 }
 
+bool Attribute::doesAttrKindHaveArgument(Attribute::AttrKind AttrKind) {
+  return AttrKind == Attribute::Alignment ||
+         AttrKind == Attribute::StackAlignment ||
+         AttrKind == Attribute::Dereferenceable ||
+         AttrKind == Attribute::AllocSize ||
+         AttrKind == Attribute::DereferenceableOrNull;
+}
+
 //===----------------------------------------------------------------------===//
 // Attribute Accessor Methods
 //===----------------------------------------------------------------------===//
 
 bool Attribute::isEnumAttribute() const {
   return pImpl && pImpl->isEnumAttribute();
 }
 
void AttrBuilder::clear() {
   StackAlignment.reset();
   DerefBytes = DerefOrNullBytes = 0;
   AllocSizeArgs = 0;
   ByValType = nullptr;
 }
 
 AttrBuilder &AttrBuilder::addAttribute(Attribute::AttrKind Val) {
   assert((unsigned)Val < Attribute::EndAttrKinds && "Attribute out of range!");
-  assert(Val != Attribute::Alignment && Val != Attribute::StackAlignment &&
-         Val != Attribute::Dereferenceable && Val != Attribute::AllocSize &&
+  assert(!Attribute::doesAttrKindHaveArgument(Val) &&
          "Adding integer attribute without adding a value!");
   Attrs[Val] = true;
   return *this;
 }
 
 AttrBuilder &AttrBuilder::addAttribute(Attribute Attr) {
   if (Attr.isStringAttribute()) {
     addAttribute(Attr.getKindAsString(), Attr.getValueAsString());

llvm/lib/IR/Verifier.cpp

 }
 
 void Verifier::verifyAttributeTypes(AttributeSet Attrs, bool IsFunction,
                                     const Value *V) {
   for (Attribute A : Attrs) {
     if (A.isStringAttribute())
       continue;
 
+    if (A.isIntAttribute() !=
+        Attribute::doesAttrKindHaveArgument(A.getKindAsEnum())) {
+      CheckFailed("Attribute '" + A.getAsString() + "' should have an Argument",
+                  V);
+      return;
+    }
+
     if (isFuncOnlyAttr(A.getKindAsEnum())) {
       if (!IsFunction) {
         CheckFailed("Attribute '" + A.getAsString() +
                         "' only applies to functions!",
                     V);
         return;
       }
     } else if (IsFunction && !isFuncOrArgAttr(A.getKindAsEnum())) {

llvm/lib/Transforms/Utils/KnowledgeRetention.cpp

struct AssumeBuilderState {
   CallInst *build() {
     if (AssumedKnowledgeSet.empty())
       return nullptr;
     Function *FnAssume = Intrinsic::getDeclaration(M, Intrinsic::assume);
     LLVMContext &C = M->getContext();
     SmallVector<OperandBundleDef, 8> OpBundle;
     for (const AssumedKnowledge &Elem : AssumedKnowledgeSet) {
       SmallVector<Value *, 2> Args;
+      assert(Attribute::getAttrKindFromName(Elem.Name) ==
+                 Attribute::AttrKind::None ||
+             static_cast<bool>(Elem.Argument) ==
+                 Attribute::doesAttrKindHaveArgument(
+                     Attribute::getAttrKindFromName(Elem.Name)));
       if (Elem.WasOn.getPointer())
         Args.push_back(Elem.WasOn.getPointer());
       if (Elem.Argument)
         Args.push_back(Elem.Argument);
       OpBundle.push_back(OperandBundleDefT<Value *>(Elem.Name, Args));
     }
     llvm::sort(OpBundle, isLowerOpBundle);
     return CallInst::Create(