diff --git a/llvm/include/llvm/Support/Allocator.h b/llvm/include/llvm/Support/Allocator.h
index bc0265904ef65..fffcbd9f3c1d8 100644
--- a/llvm/include/llvm/Support/Allocator.h
+++ b/llvm/include/llvm/Support/Allocator.h
@@ -380,7 +380,7 @@ class BumpPtrAllocatorImpl
 
 /// The standard BumpPtrAllocator which just uses the default template
 /// parameters.
-typedef BumpPtrAllocatorImpl<> BumpPtrAllocator;
+using BumpPtrAllocator = BumpPtrAllocatorImpl<>;
 
 /// A BumpPtrAllocator that allows only elements of a specific type to be
 /// allocated.
diff --git a/llvm/include/llvm/Support/Atomic.h b/llvm/include/llvm/Support/Atomic.h
index c2d9ae2da231c..3c62672a077f1 100644
--- a/llvm/include/llvm/Support/Atomic.h
+++ b/llvm/include/llvm/Support/Atomic.h
@@ -30,9 +30,9 @@ namespace llvm {
   LLVM_ABI void MemoryFence();
 
 #ifdef _MSC_VER
-  typedef long cas_flag;
+  using cas_flag = long;
 #else
-  typedef uint32_t cas_flag;
+  using cas_flag = uint32_t;
 #endif
   LLVM_ABI cas_flag CompareAndSwap(volatile cas_flag *ptr, cas_flag new_value,
                                    cas_flag old_value);
diff --git a/llvm/include/llvm/Support/BinaryStreamArray.h b/llvm/include/llvm/Support/BinaryStreamArray.h
index ef2233c53ec2c..a7d03f6511f12 100644
--- a/llvm/include/llvm/Support/BinaryStreamArray.h
+++ b/llvm/include/llvm/Support/BinaryStreamArray.h
@@ -93,7 +93,7 @@ class VarStreamArray {
   friend class VarStreamArrayIterator<ValueType, Extractor>;
 
 public:
-  typedef VarStreamArrayIterator<ValueType, Extractor> Iterator;
+  using Iterator = VarStreamArrayIterator<ValueType, Extractor>;
 
   VarStreamArray() = default;
 
@@ -156,8 +156,8 @@ template <typename ValueType, typename Extractor>
 class VarStreamArrayIterator
     : public iterator_facade_base<VarStreamArrayIterator<ValueType, Extractor>,
                                   std::forward_iterator_tag, const ValueType> {
-  typedef VarStreamArrayIterator<ValueType, Extractor> IterType;
-  typedef VarStreamArray<ValueType, Extractor> ArrayType;
+  using IterType = VarStreamArrayIterator<ValueType, Extractor>;
+  using ArrayType = VarStreamArray<ValueType, Extractor>;
 
 public:
   VarStreamArrayIterator(const ArrayType &Array, const Extractor &E,
@@ -260,7 +260,7 @@ template <typename T> class FixedStreamArray {
   friend class FixedStreamArrayIterator<T>;
 
 public:
-  typedef FixedStreamArrayIterator<T> Iterator;
+  using Iterator = FixedStreamArrayIterator<T>;
 
   FixedStreamArray() = default;
   explicit FixedStreamArray(BinaryStreamRef Stream) : Stream(Stream) {
diff --git a/llvm/include/llvm/Support/Chrono.h b/llvm/include/llvm/Support/Chrono.h
index 5b8102d8e11cf..e5f98249cc074 100644
--- a/llvm/include/llvm/Support/Chrono.h
+++ b/llvm/include/llvm/Support/Chrono.h
@@ -150,10 +150,10 @@ template <> struct unit<std::nano> {
 template <typename Rep, typename Period>
 struct format_provider<std::chrono::duration<Rep, Period>> {
 private:
-  typedef std::chrono::duration<Rep, Period> Dur;
-  typedef std::conditional_t<std::chrono::treat_as_floating_point<Rep>::value,
-                             double, intmax_t>
-      InternalRep;
+  using Dur = std::chrono::duration<Rep, Period>;
+  using InternalRep =
+      std::conditional_t<std::chrono::treat_as_floating_point<Rep>::value,
+                         double, intmax_t>;
 
   template <typename AsPeriod> static InternalRep getAs(const Dur &D) {
     using namespace std::chrono;
diff --git a/llvm/include/llvm/Support/ConvertUTF.h b/llvm/include/llvm/Support/ConvertUTF.h
index bb1723518a490..ddf7057bff59d 100644
--- a/llvm/include/llvm/Support/ConvertUTF.h
+++ b/llvm/include/llvm/Support/ConvertUTF.h
@@ -126,10 +126,10 @@ namespace llvm {
     bit mask & shift operations.
 ------------------------------------------------------------------------ */
 
-typedef unsigned int    UTF32;  /* at least 32 bits */
-typedef unsigned short  UTF16;  /* at least 16 bits */
-typedef unsigned char   UTF8;   /* typically 8 bits */
-typedef unsigned char   Boolean; /* 0 or 1 */
+using UTF32 = unsigned int;    /* at least 32 bits */
+using UTF16 = unsigned short;  /* at least 16 bits */
+using UTF8 = unsigned char;    /* typically 8 bits */
+using Boolean = unsigned char; /* 0 or 1 */
 
 /* Some fundamental constants */
 #define UNI_REPLACEMENT_CHAR (UTF32)0x0000FFFD
@@ -146,17 +146,14 @@ typedef unsigned char   Boolean; /* 0 or 1 */
 #define UNI_UTF32_BYTE_ORDER_MARK_NATIVE 0x0000FEFF
 #define UNI_UTF32_BYTE_ORDER_MARK_SWAPPED 0xFFFE0000
 
-typedef enum {
-  conversionOK,           /* conversion successful */
-  sourceExhausted,        /* partial character in source, but hit end */
-  targetExhausted,        /* insuff. room in target for conversion */
-  sourceIllegal           /* source sequence is illegal/malformed */
-} ConversionResult;
-
-typedef enum {
-  strictConversion = 0,
-  lenientConversion
-} ConversionFlags;
+enum ConversionResult {
+  conversionOK,    /* conversion successful */
+  sourceExhausted, /* partial character in source, but hit end */
+  targetExhausted, /* insuff. room in target for conversion */
+  sourceIllegal    /* source sequence is illegal/malformed */
+};
+
+enum ConversionFlags { strictConversion = 0, lenientConversion };
 
 LLVM_ABI ConversionResult ConvertUTF8toUTF16(const UTF8 **sourceStart,
                                              const UTF8 *sourceEnd,
diff --git a/llvm/include/llvm/Support/DebugCounter.h b/llvm/include/llvm/Support/DebugCounter.h
index 39a08d499b67e..9904a0dd86559 100644
--- a/llvm/include/llvm/Support/DebugCounter.h
+++ b/llvm/include/llvm/Support/DebugCounter.h
@@ -140,7 +140,7 @@ class DebugCounter {
   }
 
   // Iterate through the registered counters
-  typedef UniqueVector<std::string> CounterVector;
+  using CounterVector = UniqueVector<std::string>;
   CounterVector::const_iterator begin() const {
     return RegisteredCounters.begin();
   }
diff --git a/llvm/include/llvm/Support/ErrorHandling.h b/llvm/include/llvm/Support/ErrorHandling.h
index 4c17b6e83acd2..a4fd008a9ff3f 100644
--- a/llvm/include/llvm/Support/ErrorHandling.h
+++ b/llvm/include/llvm/Support/ErrorHandling.h
@@ -21,8 +21,8 @@ class StringRef;
 class Twine;
 
 /// An error handler callback.
-typedef void (*fatal_error_handler_t)(void *user_data, const char *reason,
-                                      bool gen_crash_diag);
+using fatal_error_handler_t = void (*)(void *user_data, const char *reason,
+                                       bool gen_crash_diag);
 
 /// install_fatal_error_handler - Installs a new error handler to be used
 /// whenever a serious (non-recoverable) error is encountered by LLVM.
diff --git a/llvm/include/llvm/Support/FormatVariadicDetails.h b/llvm/include/llvm/Support/FormatVariadicDetails.h
index 0fdc7b6f94da7..c0b245e297a58 100644
--- a/llvm/include/llvm/Support/FormatVariadicDetails.h
+++ b/llvm/include/llvm/Support/FormatVariadicDetails.h
@@ -63,8 +63,8 @@ template <typename T> class missing_format_adapter;
 template <class T> class has_FormatProvider {
 public:
   using Decayed = std::decay_t<T>;
-  typedef void (*Signature_format)(const Decayed &, llvm::raw_ostream &,
-                                   StringRef);
+  using Signature_format = void (*)(const Decayed &, llvm::raw_ostream &,
+                                    StringRef);
 
   template <typename U> using check = SameType<Signature_format, &U::format>;
 
diff --git a/llvm/include/llvm/Support/GenericLoopInfo.h b/llvm/include/llvm/Support/GenericLoopInfo.h
index b6bb360d9868f..9e2f61fd03e78 100644
--- a/llvm/include/llvm/Support/GenericLoopInfo.h
+++ b/llvm/include/llvm/Support/GenericLoopInfo.h
@@ -150,9 +150,9 @@ template <class BlockT, class LoopT> class LoopBase {
     assert(!isInvalid() && "Loop not in a valid state!");
     return SubLoops;
   }
-  typedef typename std::vector<LoopT *>::const_iterator iterator;
-  typedef
-      typename std::vector<LoopT *>::const_reverse_iterator reverse_iterator;
+  using iterator = typename std::vector<LoopT *>::const_iterator;
+  using reverse_iterator =
+      typename std::vector<LoopT *>::const_reverse_iterator;
   iterator begin() const { return getSubLoops().begin(); }
   iterator end() const { return getSubLoops().end(); }
   reverse_iterator rbegin() const { return getSubLoops().rbegin(); }
@@ -174,7 +174,7 @@ template <class BlockT, class LoopT> class LoopBase {
     assert(!isInvalid() && "Loop not in a valid state!");
     return Blocks;
   }
-  typedef typename ArrayRef<BlockT *>::const_iterator block_iterator;
+  using block_iterator = typename ArrayRef<BlockT *>::const_iterator;
   block_iterator block_begin() const { return getBlocks().begin(); }
   block_iterator block_end() const { return getBlocks().end(); }
   inline iterator_range<block_iterator> blocks() const {
@@ -302,7 +302,7 @@ template <class BlockT, class LoopT> class LoopBase {
   bool hasNoExitBlocks() const;
 
   /// Edge type.
-  typedef std::pair<BlockT *, BlockT *> Edge;
+  using Edge = std::pair<BlockT *, BlockT *>;
 
   /// Return all pairs of (_inside_block_,_outside_block_).
   void getExitEdges(SmallVectorImpl<Edge> &ExitEdges) const;
@@ -575,9 +575,9 @@ template <class BlockT, class LoopT> class LoopInfoBase {
   /// iterator/begin/end - The interface to the top-level loops in the current
   /// function.
   ///
-  typedef typename std::vector<LoopT *>::const_iterator iterator;
-  typedef
-      typename std::vector<LoopT *>::const_reverse_iterator reverse_iterator;
+  using iterator = typename std::vector<LoopT *>::const_iterator;
+  using reverse_iterator =
+      typename std::vector<LoopT *>::const_reverse_iterator;
   iterator begin() const { return TopLevelLoops.begin(); }
   iterator end() const { return TopLevelLoops.end(); }
   reverse_iterator rbegin() const { return TopLevelLoops.rbegin(); }
diff --git a/llvm/include/llvm/Support/GenericLoopInfoImpl.h b/llvm/include/llvm/Support/GenericLoopInfoImpl.h
index 541678001a8ff..c830f0a67a448 100644
--- a/llvm/include/llvm/Support/GenericLoopInfoImpl.h
+++ b/llvm/include/llvm/Support/GenericLoopInfoImpl.h
@@ -459,7 +459,7 @@ template <class BlockT, class LoopT>
 static void discoverAndMapSubloop(LoopT *L, ArrayRef<BlockT *> Backedges,
                                   LoopInfoBase<BlockT, LoopT> *LI,
                                   const DomTreeBase<BlockT> &DomTree) {
-  typedef GraphTraits<Inverse<BlockT *>> InvBlockTraits;
+  using InvBlockTraits = GraphTraits<Inverse<BlockT *>>;
 
   unsigned NumBlocks = 0;
   unsigned NumSubloops = 0;
@@ -513,8 +513,8 @@ static void discoverAndMapSubloop(LoopT *L, ArrayRef<BlockT *> Backedges,
 
 /// Populate all loop data in a stable order during a single forward DFS.
 template <class BlockT, class LoopT> class PopulateLoopsDFS {
-  typedef GraphTraits<BlockT *> BlockTraits;
-  typedef typename BlockTraits::ChildIteratorType SuccIterTy;
+  using BlockTraits = GraphTraits<BlockT *>;
+  using SuccIterTy = typename BlockTraits::ChildIteratorType;
 
   LoopInfoBase<BlockT, LoopT> *LI;
 
diff --git a/llvm/include/llvm/Support/MD5.h b/llvm/include/llvm/Support/MD5.h
index 4ba386753f397..dbcb66d7680e4 100644
--- a/llvm/include/llvm/Support/MD5.h
+++ b/llvm/include/llvm/Support/MD5.h
@@ -90,7 +90,7 @@ class MD5 {
 
 private:
   // Any 32-bit or wider unsigned integer data type will do.
-  typedef uint32_t MD5_u32plus;
+  using MD5_u32plus = uint32_t;
 
   // Internal State
   struct {
diff --git a/llvm/include/llvm/Support/Mutex.h b/llvm/include/llvm/Support/Mutex.h
index d61e3fd96efbe..3ca5c9a2f6be8 100644
--- a/llvm/include/llvm/Support/Mutex.h
+++ b/llvm/include/llvm/Support/Mutex.h
@@ -63,12 +63,12 @@ namespace llvm
     };
 
     /// Mutex - A standard, always enforced mutex.
-    typedef SmartMutex<false> Mutex;
+    using Mutex = SmartMutex<false>;
 
     template <bool mt_only>
     using SmartScopedLock = std::lock_guard<SmartMutex<mt_only>>;
 
-    typedef SmartScopedLock<false> ScopedLock;
+    using ScopedLock = SmartScopedLock<false>;
   }
 }
 
diff --git a/llvm/include/llvm/Support/OnDiskHashTable.h b/llvm/include/llvm/Support/OnDiskHashTable.h
index d7d72cfbbc649..54c6b713478b9 100644
--- a/llvm/include/llvm/Support/OnDiskHashTable.h
+++ b/llvm/include/llvm/Support/OnDiskHashTable.h
@@ -69,7 +69,7 @@ template <typename Info> class OnDiskChainedHashTableGenerator {
         : Key(Key), Data(Data), Next(nullptr), Hash(InfoObj.ComputeHash(Key)) {}
   };
 
-  typedef typename Info::offset_type offset_type;
+  using offset_type = typename Info::offset_type;
   offset_type NumBuckets;
   offset_type NumEntries;
   llvm::SpecificBumpPtrAllocator<Item> BA;
@@ -278,12 +278,12 @@ template <typename Info> class OnDiskChainedHashTable {
   Info InfoObj;
 
 public:
-  typedef Info InfoType;
-  typedef typename Info::internal_key_type internal_key_type;
-  typedef typename Info::external_key_type external_key_type;
-  typedef typename Info::data_type data_type;
-  typedef typename Info::hash_value_type hash_value_type;
-  typedef typename Info::offset_type offset_type;
+  using InfoType = Info;
+  using internal_key_type = typename Info::internal_key_type;
+  using external_key_type = typename Info::external_key_type;
+  using data_type = typename Info::data_type;
+  using hash_value_type = typename Info::hash_value_type;
+  using offset_type = typename Info::offset_type;
 
   OnDiskChainedHashTable(offset_type NumBuckets, offset_type NumEntries,
                          const unsigned char *Buckets,
@@ -435,12 +435,12 @@ class OnDiskIterableChainedHashTable : public OnDiskChainedHashTable<Info> {
   const unsigned char *Payload;
 
 public:
-  typedef OnDiskChainedHashTable<Info>          base_type;
-  typedef typename base_type::internal_key_type internal_key_type;
-  typedef typename base_type::external_key_type external_key_type;
-  typedef typename base_type::data_type         data_type;
-  typedef typename base_type::hash_value_type   hash_value_type;
-  typedef typename base_type::offset_type       offset_type;
+  using base_type = OnDiskChainedHashTable<Info>;
+  using internal_key_type = typename base_type::internal_key_type;
+  using external_key_type = typename base_type::external_key_type;
+  using data_type = typename base_type::data_type;
+  using hash_value_type = typename base_type::hash_value_type;
+  using offset_type = typename base_type::offset_type;
 
 private:
   /// Iterates over all of the keys in the table.
@@ -450,7 +450,7 @@ class OnDiskIterableChainedHashTable : public OnDiskChainedHashTable<Info> {
     offset_type NumEntriesLeft;
 
   public:
-    typedef external_key_type value_type;
+    using value_type = external_key_type;
 
     iterator_base(const unsigned char *const Ptr, offset_type NumEntries)
         : Ptr(Ptr), NumItemsInBucketLeft(0), NumEntriesLeft(NumEntries) {}
@@ -505,7 +505,7 @@ class OnDiskIterableChainedHashTable : public OnDiskChainedHashTable<Info> {
     Info *InfoObj;
 
   public:
-    typedef external_key_type value_type;
+    using value_type = external_key_type;
 
     key_iterator(const unsigned char *const Ptr, offset_type NumEntries,
                  Info *InfoObj)
@@ -551,7 +551,7 @@ class OnDiskIterableChainedHashTable : public OnDiskChainedHashTable<Info> {
     Info *InfoObj;
 
   public:
-    typedef data_type value_type;
+    using value_type = data_type;
 
     data_iterator(const unsigned char *const Ptr, offset_type NumEntries,
                   Info *InfoObj)
diff --git a/llvm/include/llvm/Support/PointerLikeTypeTraits.h b/llvm/include/llvm/Support/PointerLikeTypeTraits.h
index 320f6b63b447e..a47d68406acf3 100644
--- a/llvm/include/llvm/Support/PointerLikeTypeTraits.h
+++ b/llvm/include/llvm/Support/PointerLikeTypeTraits.h
@@ -70,7 +70,7 @@ template <> struct PointerLikeTypeTraits<void *> {
 
 // Provide PointerLikeTypeTraits for const things.
 template <typename T> struct PointerLikeTypeTraits<const T> {
-  typedef PointerLikeTypeTraits<T> NonConst;
+  using NonConst = PointerLikeTypeTraits<T>;
 
   static inline const void *getAsVoidPointer(const T P) {
     return NonConst::getAsVoidPointer(P);
@@ -83,7 +83,7 @@ template <typename T> struct PointerLikeTypeTraits<const T> {
 
 // Provide PointerLikeTypeTraits for const pointers.
 template <typename T> struct PointerLikeTypeTraits<const T *> {
-  typedef PointerLikeTypeTraits<T *> NonConst;
+  using NonConst = PointerLikeTypeTraits<T *>;
 
   static inline const void *getAsVoidPointer(const T *P) {
     return NonConst::getAsVoidPointer(const_cast<T *>(P));
diff --git a/llvm/include/llvm/Support/Program.h b/llvm/include/llvm/Support/Program.h
index 53c2e7597b2b4..575e416587ea8 100644
--- a/llvm/include/llvm/Support/Program.h
+++ b/llvm/include/llvm/Support/Program.h
@@ -39,8 +39,8 @@ const char EnvPathSeparator = ';';
 typedef unsigned long procid_t; // Must match the type of DWORD on Windows.
 typedef void *process_t;        // Must match the type of HANDLE on Windows.
 #else
-typedef ::pid_t procid_t;
-typedef procid_t process_t;
+using procid_t = ::pid_t;
+using process_t = procid_t;
 #endif
 
 /// This struct encapsulates information about a process.
diff --git a/llvm/include/llvm/Support/RISCVISAUtils.h b/llvm/include/llvm/Support/RISCVISAUtils.h
index 165bb08d66431..05fd32e0e7cfe 100644
--- a/llvm/include/llvm/Support/RISCVISAUtils.h
+++ b/llvm/include/llvm/Support/RISCVISAUtils.h
@@ -40,8 +40,8 @@ struct ExtensionComparator {
 
 /// OrderedExtensionMap is std::map, it's specialized to keep entries
 /// in canonical order of extension.
-typedef std::map<std::string, ExtensionVersion, ExtensionComparator>
-    OrderedExtensionMap;
+using OrderedExtensionMap =
+    std::map<std::string, ExtensionVersion, ExtensionComparator>;
 
 } // namespace RISCVISAUtils
 
diff --git a/llvm/include/llvm/Support/RWMutex.h b/llvm/include/llvm/Support/RWMutex.h
index 8d221aaab9ab9..efc1ca19a1208 100644
--- a/llvm/include/llvm/Support/RWMutex.h
+++ b/llvm/include/llvm/Support/RWMutex.h
@@ -162,7 +162,7 @@ template <bool mt_only> class SmartRWMutex {
   bool try_lock() { return impl.try_lock(); }
 };
 
-typedef SmartRWMutex<false> RWMutex;
+using RWMutex = SmartRWMutex<false>;
 
 /// ScopedReader - RAII acquisition of a reader lock
 #if !defined(LLVM_USE_RW_MUTEX_IMPL)
@@ -179,7 +179,7 @@ template <bool mt_only> struct SmartScopedReader {
   ~SmartScopedReader() { mutex.unlock_shared(); }
 };
 #endif
-typedef SmartScopedReader<false> ScopedReader;
+using ScopedReader = SmartScopedReader<false>;
 
 /// ScopedWriter - RAII acquisition of a writer lock
 #if !defined(LLVM_USE_RW_MUTEX_IMPL)
@@ -196,7 +196,7 @@ template <bool mt_only> struct SmartScopedWriter {
   ~SmartScopedWriter() { mutex.unlock(); }
 };
 #endif
-typedef SmartScopedWriter<false> ScopedWriter;
+using ScopedWriter = SmartScopedWriter<false>;
 
 } // end namespace sys
 } // end namespace llvm
diff --git a/llvm/include/llvm/Support/Registry.h b/llvm/include/llvm/Support/Registry.h
index c02f15e5e32b8..acd3b06fde6e7 100644
--- a/llvm/include/llvm/Support/Registry.h
+++ b/llvm/include/llvm/Support/Registry.h
@@ -43,8 +43,8 @@ namespace llvm {
   template <typename T>
   class Registry {
   public:
-    typedef T type;
-    typedef SimpleRegistryEntry<T> entry;
+    using type = T;
+    using entry = SimpleRegistryEntry<T>;
 
     class node;
     class iterator;
diff --git a/llvm/include/llvm/Support/ScaledNumber.h b/llvm/include/llvm/Support/ScaledNumber.h
index 07baf153e10c6..8ca8d457e339e 100644
--- a/llvm/include/llvm/Support/ScaledNumber.h
+++ b/llvm/include/llvm/Support/ScaledNumber.h
@@ -498,10 +498,10 @@ template <class DigitsT> class ScaledNumber : ScaledNumberBase {
   static_assert(!std::numeric_limits<DigitsT>::is_signed,
                 "only unsigned floats supported");
 
-  typedef DigitsT DigitsType;
+  using DigitsType = DigitsT;
 
 private:
-  typedef std::numeric_limits<DigitsType> DigitsLimits;
+  using DigitsLimits = std::numeric_limits<DigitsType>;
 
   static constexpr int Width = sizeof(DigitsType) * 8;
   static_assert(Width <= 64, "invalid integer width for digits");
@@ -782,7 +782,7 @@ uint64_t ScaledNumber<DigitsT>::scale(uint64_t N) const {
 template <class DigitsT>
 template <class IntT>
 IntT ScaledNumber<DigitsT>::toInt() const {
-  typedef std::numeric_limits<IntT> Limits;
+  using Limits = std::numeric_limits<IntT>;
   if (*this < 1)
     return 0;
   if (*this >= Limits::max())
diff --git a/llvm/include/llvm/Support/SuffixTree.h b/llvm/include/llvm/Support/SuffixTree.h
index 4c78235abf508..eac66d84d6f63 100644
--- a/llvm/include/llvm/Support/SuffixTree.h
+++ b/llvm/include/llvm/Support/SuffixTree.h
@@ -219,7 +219,7 @@ class SuffixTree {
     }
   };
 
-  typedef RepeatedSubstringIterator iterator;
+  using iterator = RepeatedSubstringIterator;
   iterator begin() { return iterator(Root, LeafNodes); }
   iterator end() { return iterator(nullptr); }
 };
diff --git a/llvm/include/llvm/Support/Threading.h b/llvm/include/llvm/Support/Threading.h
index 88846807f111a..89d90b3438e92 100644
--- a/llvm/include/llvm/Support/Threading.h
+++ b/llvm/include/llvm/Support/Threading.h
@@ -53,7 +53,7 @@ constexpr bool llvm_is_multithreaded() { return LLVM_ENABLE_THREADS; }
 
 #if LLVM_THREADING_USE_STD_CALL_ONCE
 
-  typedef std::once_flag once_flag;
+using once_flag = std::once_flag;
 
 #else
 
diff --git a/llvm/include/llvm/Support/TrailingObjects.h b/llvm/include/llvm/Support/TrailingObjects.h
index c47976524dcd9..218c2e336d77b 100644
--- a/llvm/include/llvm/Support/TrailingObjects.h
+++ b/llvm/include/llvm/Support/TrailingObjects.h
@@ -76,7 +76,7 @@ class TrailingObjectsBase {
 // number of a different type. e.g.:
 //   ExtractSecondType<Foo..., int>::type
 template <typename Ty1, typename Ty2> struct ExtractSecondType {
-  typedef Ty2 type;
+  using type = Ty2;
 };
 
 // TrailingObjectsImpl is somewhat complicated, because it is a
@@ -101,8 +101,8 @@ class TrailingObjectsImpl<Align, BaseTy, TopTrailingObj, PrevTy, NextTy,
     : public TrailingObjectsImpl<Align, BaseTy, TopTrailingObj, NextTy,
                                  MoreTys...> {
 
-  typedef TrailingObjectsImpl<Align, BaseTy, TopTrailingObj, NextTy, MoreTys...>
-      ParentType;
+  using ParentType =
+      TrailingObjectsImpl<Align, BaseTy, TopTrailingObj, NextTy, MoreTys...>;
 
   struct RequiresRealignment {
     static const bool value = alignof(PrevTy) < alignof(NextTy);
diff --git a/llvm/include/llvm/Support/UnicodeCharRanges.h b/llvm/include/llvm/Support/UnicodeCharRanges.h
index 7f1a9b3ff0c3b..2b5fc83d34690 100644
--- a/llvm/include/llvm/Support/UnicodeCharRanges.h
+++ b/llvm/include/llvm/Support/UnicodeCharRanges.h
@@ -37,7 +37,7 @@ inline bool operator<(UnicodeCharRange Range, uint32_t Value) {
 /// array.
 class UnicodeCharSet {
 public:
-  typedef ArrayRef<UnicodeCharRange> CharRanges;
+  using CharRanges = ArrayRef<UnicodeCharRange>;
 
   /// Constructs a UnicodeCharSet instance from an array of
   /// UnicodeCharRanges.
diff --git a/llvm/include/llvm/Support/float128.h b/llvm/include/llvm/Support/float128.h
index e15a98dc5a677..ffad1241c3e3d 100644
--- a/llvm/include/llvm/Support/float128.h
+++ b/llvm/include/llvm/Support/float128.h
@@ -14,7 +14,7 @@ namespace llvm {
 #if defined(__clang__) && defined(__FLOAT128__) &&                             \
     defined(__SIZEOF_INT128__) && !defined(__LONG_DOUBLE_IBM128__)
 #define HAS_IEE754_FLOAT128
-typedef __float128 float128;
+using float128 = __float128;
 #elif defined(__FLOAT128__) && defined(__SIZEOF_INT128__) &&                   \
     !defined(__LONG_DOUBLE_IBM128__) &&                                        \
     (defined(__GNUC__) || defined(__GNUG__))
diff --git a/llvm/include/llvm/Support/thread.h b/llvm/include/llvm/Support/thread.h
index 16e322bfd8785..ecde62d8368e7 100644
--- a/llvm/include/llvm/Support/thread.h
+++ b/llvm/include/llvm/Support/thread.h
@@ -127,7 +127,7 @@ LLVM_ABI thread::id llvm_thread_get_current_id_impl();
 template <class Function, class... Args>
 thread::thread(std::optional<unsigned> StackSizeInBytes, Function &&f,
                Args &&...args) {
-  typedef std::tuple<std::decay_t<Function>, std::decay_t<Args>...> CalleeTuple;
+  using CalleeTuple = std::tuple<std::decay_t<Function>, std::decay_t<Args>...>;
   std::unique_ptr<CalleeTuple> Callee(
       new CalleeTuple(std::forward<Function>(f), std::forward<Args>(args)...));
 
diff --git a/llvm/lib/Support/BalancedPartitioning.cpp b/llvm/lib/Support/BalancedPartitioning.cpp
index 1914f4cc39d96..d859abddbcad8 100644
--- a/llvm/lib/Support/BalancedPartitioning.cpp
+++ b/llvm/lib/Support/BalancedPartitioning.cpp
@@ -231,7 +231,7 @@ unsigned BalancedPartitioning::runIteration(const FunctionNodeRange Nodes,
   }
 
   // Compute move gains
-  typedef std::pair<float, BPFunctionNode *> GainPair;
+  using GainPair = std::pair<float, BPFunctionNode *>;
   std::vector<GainPair> Gains;
   for (auto &N : Nodes) {
     bool FromLeftToRight = (N.Bucket == LeftBucket);
diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
index de5bd795403dc..dab8beeff7ca5 100644
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -2343,10 +2343,10 @@ namespace {
 class HelpPrinter {
 protected:
   const bool ShowHidden;
-  typedef SmallVector<std::pair<const char *, Option *>, 128>
-      StrOptionPairVector;
-  typedef SmallVector<std::pair<const char *, SubCommand *>, 128>
-      StrSubCommandPairVector;
+  using StrOptionPairVector =
+      SmallVector<std::pair<const char *, Option *>, 128>;
+  using StrSubCommandPairVector =
+      SmallVector<std::pair<const char *, SubCommand *>, 128>;
   // Print the options. Opts is assumed to be alphabetically sorted.
   virtual void printOptions(StrOptionPairVector &Opts, size_t MaxArgLen) {
     for (const auto &Opt : Opts)
diff --git a/llvm/lib/Support/DAGDeltaAlgorithm.cpp b/llvm/lib/Support/DAGDeltaAlgorithm.cpp
index 981536473d124..3bfae147d18c0 100644
--- a/llvm/lib/Support/DAGDeltaAlgorithm.cpp
+++ b/llvm/lib/Support/DAGDeltaAlgorithm.cpp
@@ -47,16 +47,16 @@ class DAGDeltaAlgorithmImpl {
   friend class DeltaActiveSetHelper;
 
 public:
-  typedef DAGDeltaAlgorithm::change_ty change_ty;
-  typedef DAGDeltaAlgorithm::changeset_ty changeset_ty;
-  typedef DAGDeltaAlgorithm::changesetlist_ty changesetlist_ty;
-  typedef DAGDeltaAlgorithm::edge_ty edge_ty;
+  using change_ty = DAGDeltaAlgorithm::change_ty;
+  using changeset_ty = DAGDeltaAlgorithm::changeset_ty;
+  using changesetlist_ty = DAGDeltaAlgorithm::changesetlist_ty;
+  using edge_ty = DAGDeltaAlgorithm::edge_ty;
 
 private:
-  typedef std::vector<change_ty>::iterator pred_iterator_ty;
-  typedef std::vector<change_ty>::iterator succ_iterator_ty;
-  typedef std::set<change_ty>::iterator pred_closure_iterator_ty;
-  typedef std::set<change_ty>::iterator succ_closure_iterator_ty;
+  using pred_iterator_ty = std::vector<change_ty>::iterator;
+  using succ_iterator_ty = std::vector<change_ty>::iterator;
+  using pred_closure_iterator_ty = std::set<change_ty>::iterator;
+  using succ_closure_iterator_ty = std::set<change_ty>::iterator;
 
   DAGDeltaAlgorithm &DDA;
 
diff --git a/llvm/lib/Support/DynamicLibrary.cpp b/llvm/lib/Support/DynamicLibrary.cpp
index f1c15c00cedea..61566d3722419 100644
--- a/llvm/lib/Support/DynamicLibrary.cpp
+++ b/llvm/lib/Support/DynamicLibrary.cpp
@@ -23,7 +23,7 @@ using namespace llvm::sys;
 
 // All methods for HandleSet should be used holding SymbolsMutex.
 class DynamicLibrary::HandleSet {
-  typedef std::vector<void *> HandleList;
+  using HandleList = std::vector<void *>;
   HandleList Handles;
   void *Process = &Invalid;
 
diff --git a/llvm/lib/Support/Timer.cpp b/llvm/lib/Support/Timer.cpp
index 9d45096dddd97..b08f5083e00a8 100644
--- a/llvm/lib/Support/Timer.cpp
+++ b/llvm/lib/Support/Timer.cpp
@@ -207,7 +207,7 @@ void TimeRecord::print(const TimeRecord &Total, raw_ostream &OS) const {
 
 namespace {
 
-typedef StringMap<Timer> Name2TimerMap;
+using Name2TimerMap = StringMap<Timer>;
 
 class Name2PairMap {
   StringMap<std::pair<TimerGroup*, Name2TimerMap> > Map;