diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index cc98713241395..090a54eedaa07 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -1050,10 +1050,10 @@ static void handleDiagnoseAsBuiltinAttr(Sema &S, Decl *D,
   FunctionDecl *AttrFD = [&]() -> FunctionDecl * {
     if (!AL.isArgExpr(0))
       return nullptr;
-    auto *F = dyn_cast_or_null<DeclRefExpr>(AL.getArgAsExpr(0));
+    auto *F = dyn_cast_if_present<DeclRefExpr>(AL.getArgAsExpr(0));
     if (!F)
       return nullptr;
-    return dyn_cast_or_null<FunctionDecl>(F->getFoundDecl());
+    return dyn_cast_if_present<FunctionDecl>(F->getFoundDecl());
   }();
 
   if (!AttrFD || !AttrFD->getBuiltinID(true)) {
@@ -1452,7 +1452,7 @@ static void handlePreferredName(Sema &S, Decl *D, const ParsedAttr &AL) {
   if (!T.hasQualifiers() && T->isTypedefNameType()) {
     // Find the template name, if this type names a template specialization.
     const TemplateDecl *Template = nullptr;
-    if (const auto *CTSD = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
+    if (const auto *CTSD = dyn_cast_if_present<ClassTemplateSpecializationDecl>(
             T->getAsCXXRecordDecl())) {
       Template = CTSD->getSpecializedTemplate();
     } else if (const auto *TST = T->getAs<TemplateSpecializationType>()) {
@@ -2643,10 +2643,11 @@ static void handleAvailabilityAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   bool IsUnavailable = AL.getUnavailableLoc().isValid();
   bool IsStrict = AL.getStrictLoc().isValid();
   StringRef Str;
-  if (const auto *SE = dyn_cast_or_null<StringLiteral>(AL.getMessageExpr()))
+  if (const auto *SE = dyn_cast_if_present<StringLiteral>(AL.getMessageExpr()))
     Str = SE->getString();
   StringRef Replacement;
-  if (const auto *SE = dyn_cast_or_null<StringLiteral>(AL.getReplacementExpr()))
+  if (const auto *SE =
+          dyn_cast_if_present<StringLiteral>(AL.getReplacementExpr()))
     Replacement = SE->getString();
 
   if (II->isStr("swift")) {
@@ -2863,14 +2864,14 @@ static void handleExternalSourceSymbolAttr(Sema &S, Decl *D,
     return;
 
   StringRef Language;
-  if (const auto *SE = dyn_cast_or_null<StringLiteral>(AL.getArgAsExpr(0)))
+  if (const auto *SE = dyn_cast_if_present<StringLiteral>(AL.getArgAsExpr(0)))
     Language = SE->getString();
   StringRef DefinedIn;
-  if (const auto *SE = dyn_cast_or_null<StringLiteral>(AL.getArgAsExpr(1)))
+  if (const auto *SE = dyn_cast_if_present<StringLiteral>(AL.getArgAsExpr(1)))
     DefinedIn = SE->getString();
   bool IsGeneratedDeclaration = AL.getArgAsIdent(2) != nullptr;
   StringRef USR;
-  if (const auto *SE = dyn_cast_or_null<StringLiteral>(AL.getArgAsExpr(3)))
+  if (const auto *SE = dyn_cast_if_present<StringLiteral>(AL.getArgAsExpr(3)))
     USR = SE->getString();
 
   D->addAttr(::new (S.Context) ExternalSourceSymbolAttr(
@@ -6148,7 +6149,7 @@ static void handleObjCRequiresSuperAttr(Sema &S, Decl *D,
   const auto *Method = cast<ObjCMethodDecl>(D);
 
   const DeclContext *DC = Method->getDeclContext();
-  if (const auto *PDecl = dyn_cast_or_null<ObjCProtocolDecl>(DC)) {
+  if (const auto *PDecl = dyn_cast_if_present<ObjCProtocolDecl>(DC)) {
     S.Diag(D->getBeginLoc(), diag::warn_objc_requires_super_protocol) << Attrs
                                                                       << 0;
     S.Diag(PDecl->getLocation(), diag::note_protocol_decl);