diff --git a/clang/include/clang/AST/PropertiesBase.td b/clang/include/clang/AST/PropertiesBase.td
index f952b08502db1..8a26aace90a14 100644
--- a/clang/include/clang/AST/PropertiesBase.td
+++ b/clang/include/clang/AST/PropertiesBase.td
@@ -41,7 +41,7 @@ class RefPropertyType<string className> : PropertyType<className # "*"> {
   let PackOptional =
     "value ? *value : nullptr";
   let UnpackOptional =
-    "value ? llvm::Optional<" # CXXName # ">(value) : llvm::None";
+    "value ? llvm::Optional<" # CXXName # ">(value) : std::nullopt";
 }
 
 /// Property types that correspond to a specific subclass of another type.
@@ -58,7 +58,7 @@ class DefaultValuePropertyType<string typeName = ""> : PropertyType<typeName> {
   let PackOptional =
     "value ? *value : " # CXXName # "()";
   let UnpackOptional =
-    "value.isNull() ? llvm::None : llvm::Optional<" # CXXName # ">(value)";
+    "value.isNull() ? std::nullopt : llvm::Optional<" # CXXName # ">(value)";
 }
 
 /// Property types that correspond to integer types and support optional
@@ -67,7 +67,7 @@ class CountPropertyType<string typeName = ""> : PropertyType<typeName> {
   let PackOptional =
     "value ? *value + 1 : 0";
   let UnpackOptional =
-    "value ? llvm::Optional<" # CXXName # ">(value - 1) : llvm::None";
+    "value ? llvm::Optional<" # CXXName # ">(value - 1) : std::nullopt";
 }
 
 def APInt : PropertyType<"llvm::APInt"> { let PassByReference = 1; }
diff --git a/clang/include/clang/AST/TypeProperties.td b/clang/include/clang/AST/TypeProperties.td
index 89bbc0fde7096..84cf787487b7b 100644
--- a/clang/include/clang/AST/TypeProperties.td
+++ b/clang/include/clang/AST/TypeProperties.td
@@ -668,7 +668,7 @@ let Class = TemplateSpecializationType in {
       node->isTypeAlias()
         ? llvm::Optional<QualType>(node->getAliasedType())
         : node->isCanonicalUnqualified()
-            ? llvm::None
+            ? std::nullopt
             : llvm::Optional<QualType>(node->getCanonicalTypeInternal())
     }];
   }
@@ -834,7 +834,7 @@ let Class = DependentNameType in {
   def : Property<"underlyingType", Optional<QualType>> {
     let Read = [{
       node->isCanonicalUnqualified()
-        ? llvm::None
+        ? std::nullopt
         : llvm::Optional<QualType>(node->getCanonicalTypeInternal())
     }];
   }
diff --git a/clang/utils/TableGen/ClangAttrEmitter.cpp b/clang/utils/TableGen/ClangAttrEmitter.cpp
index b7f7e507dd6cf..3ae1813d5d734 100644
--- a/clang/utils/TableGen/ClangAttrEmitter.cpp
+++ b/clang/utils/TableGen/ClangAttrEmitter.cpp
@@ -2116,7 +2116,7 @@ void PragmaClangAttributeSupport::generateParsingHelpers(raw_ostream &OS) {
   // Generate routines that check the names of sub-rules.
   OS << "Optional<attr::SubjectMatchRule> "
         "defaultIsAttributeSubjectMatchSubRuleFor(StringRef, bool) {\n";
-  OS << "  return None;\n";
+  OS << "  return std::nullopt;\n";
   OS << "}\n\n";
 
   llvm::MapVector<const Record *, std::vector<AttributeSubjectMatchRule>>
@@ -2139,7 +2139,7 @@ void PragmaClangAttributeSupport::generateParsingHelpers(raw_ostream &OS) {
         OS << "    Case(\"" << Rule.getName() << "\", " << Rule.getEnumValue()
            << ").\n";
     }
-    OS << "    Default(None);\n";
+    OS << "    Default(std::nullopt);\n";
     OS << "  return "
           "llvm::StringSwitch<Optional<attr::SubjectMatchRule>>(Name).\n";
     for (const auto &Rule : SubMatchRule.second) {
@@ -2147,7 +2147,7 @@ void PragmaClangAttributeSupport::generateParsingHelpers(raw_ostream &OS) {
         OS << "  Case(\"" << Rule.getName() << "\", " << Rule.getEnumValue()
            << ").\n";
     }
-    OS << "  Default(None);\n";
+    OS << "  Default(std::nullopt);\n";
     OS << "}\n\n";
   }
 
@@ -2171,7 +2171,7 @@ void PragmaClangAttributeSupport::generateParsingHelpers(raw_ostream &OS) {
     OS << "  Case(\"" << Rule.getName() << "\", std::make_pair("
        << Rule.getEnumValue() << ", " << SubRuleFunction << ")).\n";
   }
-  OS << "  Default(std::make_pair(None, "
+  OS << "  Default(std::make_pair(std::nullopt, "
         "defaultIsAttributeSubjectMatchSubRuleFor));\n";
   OS << "}\n\n";