diff --git a/llvm/include/llvm/ADT/DenseMap.h b/llvm/include/llvm/ADT/DenseMap.h
index 4bda50f5a5cc0..25b5262800a10 100644
--- a/llvm/include/llvm/ADT/DenseMap.h
+++ b/llvm/include/llvm/ADT/DenseMap.h
@@ -42,7 +42,7 @@ namespace detail {
 // We extend a pair to allow users to override the bucket type with their own
 // implementation without requiring two members.
 template <typename KeyT, typename ValueT>
-struct DenseMapPair : public std::pair<KeyT, ValueT> {
+struct DenseMapPair : std::pair<KeyT, ValueT> {
   using std::pair<KeyT, ValueT>::pair;
 
   KeyT &getFirst() { return std::pair<KeyT, ValueT>::first; }
diff --git a/llvm/include/llvm/ADT/DepthFirstIterator.h b/llvm/include/llvm/ADT/DepthFirstIterator.h
index 4ced758343806..3c54f321bf2d5 100644
--- a/llvm/include/llvm/ADT/DepthFirstIterator.h
+++ b/llvm/include/llvm/ADT/DepthFirstIterator.h
@@ -66,8 +66,8 @@ class df_iterator_storage<SetType, true> {
 // one more method, completed, which is invoked when all children of a
 // node have been processed. It is intended to distinguish of back and
 // cross edges in the spanning tree but is not used in the common case.
-template <typename NodeRef, unsigned SmallSize=8>
-struct df_iterator_default_set : public SmallPtrSet<NodeRef, SmallSize> {
+template <typename NodeRef, unsigned SmallSize = 8>
+struct df_iterator_default_set : SmallPtrSet<NodeRef, SmallSize> {
   using BaseSet = SmallPtrSet<NodeRef, SmallSize>;
   using iterator = typename BaseSet::iterator;
 
@@ -235,8 +235,10 @@ iterator_range<df_iterator<T>> depth_first(const T& G) {
 }
 
 // Provide global definitions of external depth first iterators...
-template <class T, class SetTy = df_iterator_default_set<typename GraphTraits<T>::NodeRef>>
-struct df_ext_iterator : public df_iterator<T, SetTy, true> {
+template <class T,
+          class SetTy =
+              df_iterator_default_set<typename GraphTraits<T>::NodeRef>>
+struct df_ext_iterator : df_iterator<T, SetTy, true> {
   df_ext_iterator(const df_iterator<T, SetTy, true> &V)
     : df_iterator<T, SetTy, true>(V) {}
 };
@@ -262,7 +264,7 @@ template <class T,
           class SetTy =
               df_iterator_default_set<typename GraphTraits<T>::NodeRef>,
           bool External = false>
-struct idf_iterator : public df_iterator<Inverse<T>, SetTy, External> {
+struct idf_iterator : df_iterator<Inverse<T>, SetTy, External> {
   idf_iterator(const df_iterator<Inverse<T>, SetTy, External> &V)
     : df_iterator<Inverse<T>, SetTy, External>(V) {}
 };
@@ -284,8 +286,10 @@ iterator_range<idf_iterator<T>> inverse_depth_first(const T& G) {
 }
 
 // Provide global definitions of external inverse depth first iterators...
-template <class T, class SetTy = df_iterator_default_set<typename GraphTraits<T>::NodeRef>>
-struct idf_ext_iterator : public idf_iterator<T, SetTy, true> {
+template <class T,
+          class SetTy =
+              df_iterator_default_set<typename GraphTraits<T>::NodeRef>>
+struct idf_ext_iterator : idf_iterator<T, SetTy, true> {
   idf_ext_iterator(const idf_iterator<T, SetTy, true> &V)
     : idf_iterator<T, SetTy, true>(V) {}
   idf_ext_iterator(const df_iterator<Inverse<T>, SetTy, true> &V)
diff --git a/llvm/include/llvm/ADT/ImmutableSet.h b/llvm/include/llvm/ADT/ImmutableSet.h
index 310539fbb0f99..8b2425e4e8fef 100644
--- a/llvm/include/llvm/ADT/ImmutableSet.h
+++ b/llvm/include/llvm/ADT/ImmutableSet.h
@@ -931,8 +931,7 @@ struct ImutProfileInfo<T*> {
 /// ImutContainerInfo - Generic definition of comparison operations for
 ///   elements of immutable containers that defaults to using
 ///   std::equal_to<> and std::less<> to perform comparison of elements.
-template <typename T>
-struct ImutContainerInfo : public ImutProfileInfo<T> {
+template <typename T> struct ImutContainerInfo : ImutProfileInfo<T> {
   using value_type = typename ImutProfileInfo<T>::value_type;
   using value_type_ref = typename ImutProfileInfo<T>::value_type_ref;
   using key_type = value_type;
@@ -957,8 +956,7 @@ struct ImutContainerInfo : public ImutProfileInfo<T> {
 /// ImutContainerInfo - Specialization for pointer values to treat pointers
 ///  as references to unique objects.  Pointers are thus compared by
 ///  their addresses.
-template <typename T>
-struct ImutContainerInfo<T*> : public ImutProfileInfo<T*> {
+template <typename T> struct ImutContainerInfo<T *> : ImutProfileInfo<T *> {
   using value_type = typename ImutProfileInfo<T*>::value_type;
   using value_type_ref = typename ImutProfileInfo<T*>::value_type_ref;
   using key_type = value_type;
diff --git a/llvm/include/llvm/ADT/PostOrderIterator.h b/llvm/include/llvm/ADT/PostOrderIterator.h
index 1cbd3c170052c..d9aa452e25d18 100644
--- a/llvm/include/llvm/ADT/PostOrderIterator.h
+++ b/llvm/include/llvm/ADT/PostOrderIterator.h
@@ -200,7 +200,7 @@ template <class T> iterator_range<po_iterator<T>> post_order(const T &G) {
 
 // Provide global definitions of external postorder iterators...
 template <class T, class SetType = std::set<typename GraphTraits<T>::NodeRef>>
-struct po_ext_iterator : public po_iterator<T, SetType, true> {
+struct po_ext_iterator : po_iterator<T, SetType, true> {
   po_ext_iterator(const po_iterator<T, SetType, true> &V) :
   po_iterator<T, SetType, true>(V) {}
 };
@@ -223,7 +223,7 @@ iterator_range<po_ext_iterator<T, SetType>> post_order_ext(const T &G, SetType &
 // Provide global definitions of inverse post order iterators...
 template <class T, class SetType = std::set<typename GraphTraits<T>::NodeRef>,
           bool External = false>
-struct ipo_iterator : public po_iterator<Inverse<T>, SetType, External> {
+struct ipo_iterator : po_iterator<Inverse<T>, SetType, External> {
   ipo_iterator(const po_iterator<Inverse<T>, SetType, External> &V) :
      po_iterator<Inverse<T>, SetType, External> (V) {}
 };
@@ -245,7 +245,7 @@ iterator_range<ipo_iterator<T>> inverse_post_order(const T &G) {
 
 // Provide global definitions of external inverse postorder iterators...
 template <class T, class SetType = std::set<typename GraphTraits<T>::NodeRef>>
-struct ipo_ext_iterator : public ipo_iterator<T, SetType, true> {
+struct ipo_ext_iterator : ipo_iterator<T, SetType, true> {
   ipo_ext_iterator(const ipo_iterator<T, SetType, true> &V) :
     ipo_iterator<T, SetType, true>(V) {}
   ipo_ext_iterator(const po_iterator<Inverse<T>, SetType, true> &V) :
diff --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h
index 658f26249122a..a9841c6651b72 100644
--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -674,7 +674,7 @@ using zip_traits = iterator_facade_base<
     ReferenceTupleType *, ReferenceTupleType>;
 
 template <typename ZipType, typename ReferenceTupleType, typename... Iters>
-struct zip_common : public zip_traits<ZipType, ReferenceTupleType, Iters...> {
+struct zip_common : zip_traits<ZipType, ReferenceTupleType, Iters...> {
   using Base = zip_traits<ZipType, ReferenceTupleType, Iters...>;
   using IndexSequence = std::index_sequence_for<Iters...>;
   using value_type = typename Base::value_type;
diff --git a/llvm/include/llvm/Support/Alignment.h b/llvm/include/llvm/Support/Alignment.h
index a4ca54e26f18d..f9d7c76836657 100644
--- a/llvm/include/llvm/Support/Alignment.h
+++ b/llvm/include/llvm/Support/Alignment.h
@@ -103,7 +103,7 @@ inline Align assumeAligned(uint64_t Value) {
 
 /// This struct is a compact representation of a valid (power of two) or
 /// undefined (0) alignment.
-struct MaybeAlign : public std::optional<Align> {
+struct MaybeAlign : std::optional<Align> {
 private:
   using UP = std::optional<Align>;
 
diff --git a/llvm/include/llvm/Support/Casting.h b/llvm/include/llvm/Support/Casting.h
index 2a9a149327d83..6f6df2e9703ea 100644
--- a/llvm/include/llvm/Support/Casting.h
+++ b/llvm/include/llvm/Support/Casting.h
@@ -340,7 +340,7 @@ struct ValueFromPointerCast
 /// during the cast. It's also a good example of how to implement a move-only
 /// cast.
 template <typename To, typename From, typename Derived = void>
-struct UniquePtrCast : public CastIsPossible<To, From *> {
+struct UniquePtrCast : CastIsPossible<To, From *> {
   using Self = detail::SelfType<Derived, UniquePtrCast<To, From>>;
   using CastResultType = std::unique_ptr<
       std::remove_reference_t<typename cast_retty<To, From>::ret_type>>;
@@ -473,7 +473,7 @@ struct ForwardToPointerCast {
 // take advantage of the cast traits whenever possible!
 
 template <typename To, typename From, typename Enable = void>
-struct CastInfo : public CastIsPossible<To, From> {
+struct CastInfo : CastIsPossible<To, From> {
   using Self = CastInfo<To, From, Enable>;
 
   using CastReturnType = typename cast_retty<To, From>::ret_type;
@@ -536,8 +536,7 @@ struct CastInfo<To, std::unique_ptr<From>> : public UniquePtrCast<To, From> {};
 /// the input is std::optional<From> that the output can be std::optional<To>.
 /// If that's not the case, specialize CastInfo for your use case.
 template <typename To, typename From>
-struct CastInfo<To, std::optional<From>> : public OptionalValueCast<To, From> {
-};
+struct CastInfo<To, std::optional<From>> : OptionalValueCast<To, From> {};
 
 /// isa<X> - Return true if the parameter to the template is an instance of one
 /// of the template type arguments.  Used like this:
diff --git a/llvm/include/llvm/Support/CommandLine.h b/llvm/include/llvm/Support/CommandLine.h
index dd05c530cc06e..5a5f00e844705 100644
--- a/llvm/include/llvm/Support/CommandLine.h
+++ b/llvm/include/llvm/Support/CommandLine.h
@@ -549,7 +549,7 @@ template <class DataType> struct OptionValue;
 // The default value safely does nothing. Option value printing is only
 // best-effort.
 template <class DataType, bool isClass>
-struct OptionValueBase : public GenericOptionValue {
+struct OptionValueBase : GenericOptionValue {
   // Temporary storage for argument passing.
   using WrapperType = OptionValue<DataType>;
 
diff --git a/llvm/include/llvm/Support/DOTGraphTraits.h b/llvm/include/llvm/Support/DOTGraphTraits.h
index bf30aa4df9fab..3b9fe00d3282f 100644
--- a/llvm/include/llvm/Support/DOTGraphTraits.h
+++ b/llvm/include/llvm/Support/DOTGraphTraits.h
@@ -162,8 +162,7 @@ struct DefaultDOTGraphTraits {
 /// graphs are converted to 'dot' graphs.  When specializing, you may inherit
 /// from DefaultDOTGraphTraits if you don't need to override everything.
 ///
-template <typename Ty>
-struct DOTGraphTraits : public DefaultDOTGraphTraits {
+template <typename Ty> struct DOTGraphTraits : DefaultDOTGraphTraits {
   using DefaultDOTGraphTraits::DefaultDOTGraphTraits;
 };
 
diff --git a/llvm/include/llvm/Support/LSP/Protocol.h b/llvm/include/llvm/Support/LSP/Protocol.h
index 93b82f1e581f8..e38203a8b4a39 100644
--- a/llvm/include/llvm/Support/LSP/Protocol.h
+++ b/llvm/include/llvm/Support/LSP/Protocol.h
@@ -449,7 +449,7 @@ struct ReferenceContext {
 bool fromJSON(const llvm::json::Value &value, ReferenceContext &result,
               llvm::json::Path path);
 
-struct ReferenceParams : public TextDocumentPositionParams {
+struct ReferenceParams : TextDocumentPositionParams {
   ReferenceContext context;
 };
 
diff --git a/llvm/include/llvm/Support/MD5.h b/llvm/include/llvm/Support/MD5.h
index ed29826bab0cb..4ba386753f397 100644
--- a/llvm/include/llvm/Support/MD5.h
+++ b/llvm/include/llvm/Support/MD5.h
@@ -41,7 +41,7 @@ template <typename T> class ArrayRef;
 
 class MD5 {
 public:
-  struct MD5Result : public std::array<uint8_t, 16> {
+  struct MD5Result : std::array<uint8_t, 16> {
     LLVM_ABI SmallString<32> digest() const;
 
     uint64_t low() const {
diff --git a/llvm/include/llvm/Support/Timer.h b/llvm/include/llvm/Support/Timer.h
index 40709d49db011..a4ed712577582 100644
--- a/llvm/include/llvm/Support/Timer.h
+++ b/llvm/include/llvm/Support/Timer.h
@@ -167,7 +167,7 @@ class TimeRegion {
 /// you to declare a new timer, AND specify the region to time, all in one
 /// statement.  All timers with the same name are merged.  This is primarily
 /// used for debugging and for hunting performance problems.
-struct NamedRegionTimer : public TimeRegion {
+struct NamedRegionTimer : TimeRegion {
   LLVM_ABI explicit NamedRegionTimer(StringRef Name, StringRef Description,
                                      StringRef GroupName,
                                      StringRef GroupDescription,