diff --git a/include/swift/AST/PluginRegistry.h b/include/swift/AST/PluginRegistry.h
index 74a323e520b80..b363362689c5a 100644
--- a/include/swift/AST/PluginRegistry.h
+++ b/include/swift/AST/PluginRegistry.h
@@ -147,7 +147,7 @@ class LoadedExecutablePlugin {
 
   /// Remove "on reconnect" callback.
   void removeOnReconnect(std::function<void(void)> *fn) {
-    llvm::erase_value(onReconnect, fn);
+    llvm::erase(onReconnect, fn);
   }
 
   llvm::sys::procid_t getPid() { return Process->process.Pid; }
diff --git a/include/swift/Basic/ExponentialGrowthAppendingBinaryByteStream.h b/include/swift/Basic/ExponentialGrowthAppendingBinaryByteStream.h
index bb48937baef9b..59df3eeb09552 100644
--- a/include/swift/Basic/ExponentialGrowthAppendingBinaryByteStream.h
+++ b/include/swift/Basic/ExponentialGrowthAppendingBinaryByteStream.h
@@ -23,6 +23,7 @@
 #include "swift/Basic/LLVM.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/BinaryByteStream.h"
+#include "llvm/Support/Endian.h"
 
 namespace swift {
 
@@ -34,13 +35,14 @@ class ExponentialGrowthAppendingBinaryByteStream
   SmallVector<uint8_t, 0> Data;
 
   /// Data in the stream is always encoded in little-endian byte order.
-  const llvm::support::endianness Endian = llvm::support::endianness::little;
+  const llvm::endianness Endian = llvm::endianness::little;
+
 public:
   ExponentialGrowthAppendingBinaryByteStream() = default;
 
   void reserve(size_t Size);
 
-  llvm::support::endianness getEndian() const override { return Endian; }
+  llvm::endianness getEndian() const override { return Endian; }
 
   llvm::Error readBytes(uint64_t Offset, uint64_t Size,
                         ArrayRef<uint8_t> &Buffer) override;
diff --git a/include/swift/Basic/StableHasher.h b/include/swift/Basic/StableHasher.h
index 786931a74607b..9a96e25fe2059 100644
--- a/include/swift/Basic/StableHasher.h
+++ b/include/swift/Basic/StableHasher.h
@@ -133,7 +133,7 @@ class StableHasher final {
       return setBufferLength(bufLen + N);
     }
 
-    constexpr auto endian = llvm::support::endianness::little;
+    constexpr auto endian = llvm::endianness::little;
     compress(llvm::support::endian::read<uint64_t>(byteBuffer, endian));
 
     // Now reseed the buffer with the remaining bytes.
@@ -146,7 +146,7 @@ class StableHasher final {
       typename T,
       typename std::enable_if<std::is_integral<T>::value>::type * = nullptr>
   void combine(T bits) {
-    constexpr auto endian = llvm::support::endianness::little;
+    constexpr auto endian = llvm::endianness::little;
     uint8_t buf[sizeof(T)] = {0};
     bits = llvm::support::endian::byte_swap<T>(bits, endian);
     std::memcpy(buf, &bits, sizeof(T));
diff --git a/include/swift/ClangImporter/ClangModule.h b/include/swift/ClangImporter/ClangModule.h
index 470c7b481f4b4..29cf61c9b64c9 100644
--- a/include/swift/ClangImporter/ClangModule.h
+++ b/include/swift/ClangImporter/ClangModule.h
@@ -20,6 +20,7 @@
 #include "swift/Basic/Version.h"
 #include "swift/ClangImporter/ClangImporter.h"
 #include "clang/AST/ExternalASTSource.h"
+#include "clang/Basic/ASTSourceDescriptor.h"
 #include "clang/Basic/Module.h"
 
 namespace clang {
diff --git a/include/swift/ClangImporter/SwiftAbstractBasicReader.h b/include/swift/ClangImporter/SwiftAbstractBasicReader.h
index 0889de8d9cc39..b5063c1c43493 100644
--- a/include/swift/ClangImporter/SwiftAbstractBasicReader.h
+++ b/include/swift/ClangImporter/SwiftAbstractBasicReader.h
@@ -72,7 +72,7 @@ class DataStreamBasicReader
       return clang::Selector();
 
     unsigned numArgs = unsigned(numArgsPlusOne - 1);
-    SmallVector<clang::IdentifierInfo *, 4> chunks;
+    SmallVector<const clang::IdentifierInfo *, 4> chunks;
     for (unsigned i = 0, e = std::max(numArgs, 1U); i != e; ++i)
       chunks.push_back(asImpl().readIdentifier());
 
@@ -94,6 +94,11 @@ class DataStreamBasicReader
     llvm::report_fatal_error("Read BTFTypeTagAttr that should never have been"
                              " serialized");
   }
+
+  template<typename T>
+  T *readDeclAs() {
+    return asImpl().template readDeclAs<T>();
+  }
 };
 
 }
diff --git a/include/swift/DependencyScan/ModuleDependencyScanner.h b/include/swift/DependencyScan/ModuleDependencyScanner.h
index a8af234469f5d..00e7877becd07 100644
--- a/include/swift/DependencyScan/ModuleDependencyScanner.h
+++ b/include/swift/DependencyScan/ModuleDependencyScanner.h
@@ -145,7 +145,7 @@ class ModuleDependencyScanner {
   /// The available pool of workers for filesystem module search
   unsigned NumThreads;
   std::list<std::unique_ptr<ModuleDependencyScanningWorker>> Workers;
-  llvm::ThreadPool ScanningThreadPool;
+  llvm::StdThreadPool ScanningThreadPool;
   /// Protect worker access.
   std::mutex WorkersLock;
 };
diff --git a/include/swift/Localization/LocalizationFormat.h b/include/swift/Localization/LocalizationFormat.h
index 78c6937e03ea6..23e38f0f49402 100644
--- a/include/swift/Localization/LocalizationFormat.h
+++ b/include/swift/Localization/LocalizationFormat.h
@@ -40,8 +40,6 @@ enum class DiagID : uint32_t;
 
 namespace diag {
 
-using namespace llvm::support;
-
 enum LocalizationProducerState : uint8_t {
   NotInitialized,
   Initialized,
@@ -77,14 +75,15 @@ class LocalizationWriterInfo {
                                                         key_type_ref key,
                                                         data_type_ref data) {
     offset_type dataLength = static_cast<offset_type>(data.size());
-    endian::write<offset_type>(out, dataLength, little);
+    llvm::support::endian::write<offset_type>(out, dataLength,
+                                              llvm::endianness::little);
     // No need to write the key length; it's constant.
     return {sizeof(key_type), dataLength};
   }
 
   void EmitKey(llvm::raw_ostream &out, key_type_ref key, unsigned len) {
     assert(len == sizeof(key_type));
-    endian::write<key_type>(out, key, little);
+    llvm::support::endian::write<key_type>(out, key, llvm::endianness::little);
   }
 
   void EmitData(llvm::raw_ostream &out, key_type_ref key, data_type_ref data,
@@ -120,12 +119,15 @@ class LocalizationReaderInfo {
   static std::pair<offset_type, offset_type>
   ReadKeyDataLength(const unsigned char *&data) {
     offset_type dataLength =
-        endian::readNext<offset_type, little, unaligned>(data);
+        llvm::support::endian::readNext<offset_type, llvm::endianness::little,
+                                        llvm::support::unaligned>(data);
     return {sizeof(uint32_t), dataLength};
   }
 
   internal_key_type ReadKey(const unsigned char *data, offset_type length) {
-    return endian::readNext<internal_key_type, little, unaligned>(data);
+    return llvm::support::endian::readNext<
+        internal_key_type, llvm::endianness::little, llvm::support::unaligned>(
+        data);
   }
 
   data_type ReadData(internal_key_type Key, const unsigned char *data,
diff --git a/include/swift/Option/Options.h b/include/swift/Option/Options.h
index 0f24e0bd7d0df..b3ce193b56f73 100644
--- a/include/swift/Option/Options.h
+++ b/include/swift/Option/Options.h
@@ -13,13 +13,9 @@
 #ifndef SWIFT_OPTION_OPTIONS_H
 #define SWIFT_OPTION_OPTIONS_H
 
-#include <memory>
+#include "llvm/Option/OptTable.h"
 
-namespace llvm {
-namespace opt {
-  class OptTable;
-}
-}
+#include <memory>
 
 namespace swift {
 namespace options {
@@ -49,9 +45,7 @@ namespace options {
 
   enum ID {
     OPT_INVALID = 0, // This is not an option ID.
-#define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
-               HELPTEXT, METAVAR, VALUES)                                      \
-    OPT_##ID,
+#define OPTION(...) LLVM_MAKE_OPT_ID(__VA_ARGS__),
 #include "swift/Option/Options.inc"
     LastOption
 #undef OPTION
diff --git a/include/swift/SIL/SILInstruction.h b/include/swift/SIL/SILInstruction.h
index e36b07f375a57..38d4c48d73ef6 100644
--- a/include/swift/SIL/SILInstruction.h
+++ b/include/swift/SIL/SILInstruction.h
@@ -94,6 +94,7 @@ template <> struct compute_node_options<::swift::SILInstruction> {
 
     static const bool enable_sentinel_tracking = false;
     static const bool is_sentinel_tracking_explicit = false;
+    static const bool has_iterator_bits = false;
     typedef void tag;
     typedef ilist_node_base<enable_sentinel_tracking> node_base_type;
     typedef SILInstructionListBase list_base_type;
diff --git a/lib/AST/ASTMangler.cpp b/lib/AST/ASTMangler.cpp
index 090a521a5c8b4..8a7aaa67b9c03 100644
--- a/lib/AST/ASTMangler.cpp
+++ b/lib/AST/ASTMangler.cpp
@@ -3038,7 +3038,7 @@ void ASTMangler::appendClangType(FnType *fn, llvm::raw_svector_ostream &out) {
       fn->getASTContext().getClangModuleLoader()->getClangASTContext();
   std::unique_ptr<clang::ItaniumMangleContext> mangler{
       clang::ItaniumMangleContext::create(clangCtx, clangCtx.getDiagnostics())};
-  mangler->mangleTypeName(clang::QualType(clangType, 0), scratchOS);
+  mangler->mangleCanonicalTypeName(clang::QualType(clangType, 0), scratchOS);
   out << scratchOS.str().size() << scratchOS.str();
 }
 
diff --git a/lib/AST/ClangTypeConverter.cpp b/lib/AST/ClangTypeConverter.cpp
index 85ae8f62458ab..2e3198dff733d 100644
--- a/lib/AST/ClangTypeConverter.cpp
+++ b/lib/AST/ClangTypeConverter.cpp
@@ -227,7 +227,7 @@ clang::QualType ClangTypeConverter::convertMemberType(NominalTypeDecl *DC,
 // we could recover in some other way.
 static clang::QualType getClangVectorType(const clang::ASTContext &ctx,
                                           clang::BuiltinType::Kind eltKind,
-                                          clang::VectorType::VectorKind vecKind,
+                                          clang::VectorKind vecKind,
                                           StringRef numEltsString) {
   unsigned numElts;
   bool failedParse = numEltsString.getAsInteger<unsigned>(10, numElts);
@@ -268,11 +268,11 @@ clang::QualType ClangTypeConverter::visitStructType(StructType *type) {
 #undef CHECK_NAMED_TYPE
 
   // Map vector types to the corresponding C vectors.
-#define MAP_SIMD_TYPE(TYPE_NAME, _, BUILTIN_KIND)                      \
-  if (name.starts_with(#TYPE_NAME)) {                                   \
-    return getClangVectorType(ctx, clang::BuiltinType::BUILTIN_KIND,   \
-                              clang::VectorType::GenericVector,        \
-                              name.drop_front(sizeof(#TYPE_NAME)-1));  \
+#define MAP_SIMD_TYPE(TYPE_NAME, _, BUILTIN_KIND)                              \
+  if (name.starts_with(#TYPE_NAME)) {                                          \
+    return getClangVectorType(ctx, clang::BuiltinType::BUILTIN_KIND,           \
+                              clang::VectorKind::Generic,                      \
+                              name.drop_front(sizeof(#TYPE_NAME) - 1));        \
   }
 #include "swift/ClangImporter/SIMDMappedTypes.def"
 
@@ -427,8 +427,8 @@ clang::QualType ClangTypeConverter::visitTupleType(TupleType *type) {
     return clang::QualType();
 
   APInt size(32, tupleNumElements);
-  return ClangASTContext.getConstantArrayType(clangEltTy, size, nullptr,
-           clang::ArrayType::Normal, 0);
+  return ClangASTContext.getConstantArrayType(
+      clangEltTy, size, nullptr, clang::ArraySizeModifier::Normal, 0);
 }
 
 clang::QualType ClangTypeConverter::visitProtocolType(ProtocolType *type) {
@@ -617,7 +617,7 @@ ClangTypeConverter::visitBoundGenericType(BoundGenericType *type) {
       return clang::QualType();
     (void) failedParse;
     auto vectorTy = ClangASTContext.getVectorType(scalarTy, numElts,
-      clang::VectorType::VectorKind::GenericVector);
+                                                  clang::VectorKind::Generic);
     return vectorTy;
   }
   }
@@ -890,8 +890,8 @@ ClangTypeConverter::getClangTemplateArguments(
     auto templateParam = cast<clang::TemplateTypeParmDecl>(param);
     // We must have found a defaulted parameter at the end of the list.
     if (templateParam->getIndex() >= genericArgs.size()) {
-      templateArgs.push_back(
-          clang::TemplateArgument(templateParam->getDefaultArgument()));
+      templateArgs.push_back(clang::TemplateArgument(
+          templateParam->getDefaultArgument().getArgument()));
       continue;
     }
 
diff --git a/lib/AST/PluginRegistry.cpp b/lib/AST/PluginRegistry.cpp
index 12a82ff9f36d9..21598ee52a01b 100644
--- a/lib/AST/PluginRegistry.cpp
+++ b/lib/AST/PluginRegistry.cpp
@@ -271,8 +271,8 @@ llvm::Error LoadedExecutablePlugin::sendMessage(llvm::StringRef message) const {
   size_t size = message.size();
 
   // Write header (message size).
-  uint64_t header = llvm::support::endian::byte_swap(
-      uint64_t(size), llvm::support::endianness::little);
+  uint64_t header = llvm::support::endian::byte_swap(uint64_t(size),
+                                                     llvm::endianness::little);
   writtenSize = Process->write(&header, sizeof(header));
   if (writtenSize != sizeof(header)) {
     setStale();
@@ -304,8 +304,8 @@ llvm::Expected<std::string> LoadedExecutablePlugin::waitForNextMessage() const {
                                    "failed to read plugin message header");
   }
 
-  size_t size = llvm::support::endian::read<uint64_t>(
-      &header, llvm::support::endianness::little);
+  size_t size =
+      llvm::support::endian::read<uint64_t>(&header, llvm::endianness::little);
 
   // Read message.
   std::string message;
diff --git a/lib/Basic/Platform.cpp b/lib/Basic/Platform.cpp
index 256f5c02254ee..eff748ca354e3 100644
--- a/lib/Basic/Platform.cpp
+++ b/lib/Basic/Platform.cpp
@@ -196,32 +196,31 @@ static StringRef getPlatformNameForDarwin(const DarwinPlatformKind platform) {
 
 StringRef swift::getPlatformNameForTriple(const llvm::Triple &triple) {
   switch (triple.getOS()) {
-  case llvm::Triple::ZOS:
-  case llvm::Triple::Ananas:
-  case llvm::Triple::CloudABI:
+  case llvm::Triple::AIX:
+  case llvm::Triple::AMDHSA:
+  case llvm::Triple::AMDPAL:
+  case llvm::Triple::BridgeOS:
+  case llvm::Triple::CUDA:
   case llvm::Triple::DragonFly:
   case llvm::Triple::DriverKit:
+  case llvm::Triple::ELFIAMCU:
   case llvm::Triple::Emscripten:
   case llvm::Triple::Fuchsia:
+  case llvm::Triple::HermitCore:
+  case llvm::Triple::Hurd:
   case llvm::Triple::KFreeBSD:
   case llvm::Triple::Lv2:
+  case llvm::Triple::Mesa3D:
+  case llvm::Triple::NaCl:
   case llvm::Triple::NetBSD:
+  case llvm::Triple::NVCL:
   case llvm::Triple::PS5:
+  case llvm::Triple::RTEMS:
+  case llvm::Triple::Serenity:
   case llvm::Triple::ShaderModel:
   case llvm::Triple::Solaris:
-  case llvm::Triple::Minix:
-  case llvm::Triple::RTEMS:
-  case llvm::Triple::NaCl:
-  case llvm::Triple::AIX:
-  case llvm::Triple::CUDA:
-  case llvm::Triple::NVCL:
-  case llvm::Triple::AMDHSA:
-  case llvm::Triple::ELFIAMCU:
-  case llvm::Triple::Mesa3D:
-  case llvm::Triple::Contiki:
-  case llvm::Triple::AMDPAL:
-  case llvm::Triple::HermitCore:
-  case llvm::Triple::Hurd:
+  case llvm::Triple::Vulkan:
+  case llvm::Triple::ZOS:
     return "";
   case llvm::Triple::Darwin:
   case llvm::Triple::MacOSX:
diff --git a/lib/ClangImporter/ClangAdapter.cpp b/lib/ClangImporter/ClangAdapter.cpp
index c96e41f26b333..23d8d22d3837f 100644
--- a/lib/ClangImporter/ClangAdapter.cpp
+++ b/lib/ClangImporter/ClangAdapter.cpp
@@ -364,6 +364,7 @@ OmissionTypeName importer::getClangTypeNameForOmission(clang::ASTContext &ctx,
     case clang::BuiltinType::Overload:
     case clang::BuiltinType::PseudoObject:
     case clang::BuiltinType::UnknownAny:
+    case clang::BuiltinType::UnresolvedTemplate:
       return OmissionTypeName();
 
     // FIXME: Types that can be mapped, but aren't yet.
@@ -464,7 +465,7 @@ OmissionTypeName importer::getClangTypeNameForOmission(clang::ASTContext &ctx,
       return OmissionTypeName();
 
     // OpenMP types that don't have Swift equivalents.
-    case clang::BuiltinType::OMPArraySection:
+    case clang::BuiltinType::ArraySection:
     case clang::BuiltinType::OMPArrayShaping:
     case clang::BuiltinType::OMPIterator:
       return OmissionTypeName();
@@ -776,7 +777,7 @@ OptionalTypeKind importer::getParamOptionality(const clang::ParmVarDecl *param,
   // Check for the 'static' annotation on C arrays.
   if (const auto *DT = dyn_cast<clang::DecayedType>(paramTy))
     if (const auto *AT = DT->getOriginalType()->getAsArrayTypeUnsafe())
-      if (AT->getSizeModifier() == clang::ArrayType::Static)
+      if (AT->getSizeModifier() == clang::ArraySizeModifier::Static)
         return OTK_None;
 
   // Default to implicitly unwrapped optionals.
diff --git a/lib/ClangImporter/ClangDerivedConformances.cpp b/lib/ClangImporter/ClangDerivedConformances.cpp
index 9219140eff63e..eaea4af632c2e 100644
--- a/lib/ClangImporter/ClangDerivedConformances.cpp
+++ b/lib/ClangImporter/ClangDerivedConformances.cpp
@@ -264,8 +264,8 @@ instantiateTemplatedOperator(ClangImporter::Implementation &impl,
 
   clang::UnresolvedSet<1> ops;
   auto qualType = clang::QualType(classDecl->getTypeForDecl(), 0);
-  auto arg = new (clangCtx)
-      clang::CXXThisExpr(clang::SourceLocation(), qualType, false);
+  auto arg = clang::CXXThisExpr::Create(clangCtx, clang::SourceLocation(),
+                                        qualType, false);
   arg->setType(clang::QualType(classDecl->getTypeForDecl(), 0));
 
   clang::OverloadedOperatorKind opKind =
diff --git a/lib/ClangImporter/ClangImporter.cpp b/lib/ClangImporter/ClangImporter.cpp
index 687a2b21045de..9ef537cd222de 100644
--- a/lib/ClangImporter/ClangImporter.cpp
+++ b/lib/ClangImporter/ClangImporter.cpp
@@ -1505,19 +1505,17 @@ ClangImporter::create(ASTContext &ctx,
   importer->Impl.objectAtIndexedSubscript
     = clangContext.Selectors.getUnarySelector(
         &clangContext.Idents.get("objectAtIndexedSubscript"));
-  clang::IdentifierInfo *setObjectAtIndexedSubscriptIdents[2] = {
-    &clangContext.Idents.get("setObject"),
-    &clangContext.Idents.get("atIndexedSubscript")
-  };
+  const clang::IdentifierInfo *setObjectAtIndexedSubscriptIdents[2] = {
+      &clangContext.Idents.get("setObject"),
+      &clangContext.Idents.get("atIndexedSubscript")};
   importer->Impl.setObjectAtIndexedSubscript
     = clangContext.Selectors.getSelector(2, setObjectAtIndexedSubscriptIdents);
   importer->Impl.objectForKeyedSubscript
     = clangContext.Selectors.getUnarySelector(
         &clangContext.Idents.get("objectForKeyedSubscript"));
-  clang::IdentifierInfo *setObjectForKeyedSubscriptIdents[2] = {
-    &clangContext.Idents.get("setObject"),
-    &clangContext.Idents.get("forKeyedSubscript")
-  };
+  const clang::IdentifierInfo *setObjectForKeyedSubscriptIdents[2] = {
+      &clangContext.Idents.get("setObject"),
+      &clangContext.Idents.get("forKeyedSubscript")};
   importer->Impl.setObjectForKeyedSubscript
     = clangContext.Selectors.getSelector(2, setObjectForKeyedSubscriptIdents);
 
@@ -2228,9 +2226,9 @@ ClangImporter::Implementation::lookupModule(StringRef moduleName) {
   if (moduleFile == PrebuiltModules.end())
     return nullptr;
 
-  if (!Instance->loadModuleFile(moduleFile->second))
+  clang::serialization::ModuleFile *Loaded = nullptr;
+  if (!Instance->loadModuleFile(moduleFile->second, Loaded))
     return nullptr; // error loading, return not found.
-  // Lookup again.
   return loadFromMM();
 }
 
@@ -2396,13 +2394,15 @@ ModuleDecl *ClangImporter::Implementation::finishLoadingClangModule(
   // instead, manually register all `.h` inputs of Clang module dependnecies.
   if (SwiftDependencyTracker &&
       !Instance->getInvocation().getLangOpts().ImplicitModules) {
-    auto *moduleFile = Instance->getASTReader()->getModuleManager().lookup(
-        clangModule->getASTFile());
-    Instance->getASTReader()->visitInputFileInfos(
-        *moduleFile, /*IncludeSystem=*/true,
-        [&](const clang::serialization::InputFileInfo &IFI, bool isSystem) {
-          SwiftDependencyTracker->addDependency(IFI.Filename, isSystem);
-        });
+    if (auto moduleRef = clangModule->getASTFile()) {
+      auto *moduleFile = Instance->getASTReader()->getModuleManager().lookup(
+          *moduleRef);
+      Instance->getASTReader()->visitInputFileInfos(
+          *moduleFile, /*IncludeSystem=*/true,
+          [&](const clang::serialization::InputFileInfo &IFI, bool isSystem) {
+            SwiftDependencyTracker->addDependency(IFI.Filename, isSystem);
+          });
+    }
   }
 
   if (clangModule->isSubModule()) {
@@ -2874,7 +2874,7 @@ ClangImporter::Implementation::exportSelector(DeclName name,
 
   clang::ASTContext &ctx = getClangASTContext();
 
-  SmallVector<clang::IdentifierInfo *, 8> pieces;
+  SmallVector<const clang::IdentifierInfo *, 8> pieces;
   pieces.push_back(exportName(name.getBaseIdentifier()).getAsIdentifierInfo());
 
   auto argNames = name.getArgumentNames();
@@ -2893,7 +2893,7 @@ ClangImporter::Implementation::exportSelector(DeclName name,
 
 clang::Selector
 ClangImporter::Implementation::exportSelector(ObjCSelector selector) {
-  SmallVector<clang::IdentifierInfo *, 4> pieces;
+  SmallVector<const clang::IdentifierInfo *, 4> pieces;
   for (auto piece : selector.getSelectorPieces())
     pieces.push_back(exportName(piece).getAsIdentifierInfo());
   return getClangASTContext().Selectors.getSelector(selector.getNumArgs(),
@@ -2909,7 +2909,7 @@ isPotentiallyConflictingSetter(const clang::ObjCProtocolDecl *proto,
   if (sel.getNumArgs() != 1)
     return false;
 
-  clang::IdentifierInfo *setterID = sel.getIdentifierInfoForSlot(0);
+  const clang::IdentifierInfo *setterID = sel.getIdentifierInfoForSlot(0);
   if (!setterID || !setterID->getName().starts_with("set"))
     return false;
 
@@ -3943,11 +3943,12 @@ void ClangModuleUnit::lookupObjCMethods(
   // Collect all of the Objective-C methods with this selector.
   SmallVector<clang::ObjCMethodDecl *, 8> objcMethods;
   auto &clangSema = owner.getClangSema();
-  clangSema.CollectMultipleMethodsInGlobalPool(clangSelector,
+  auto &clangObjc = clangSema.ObjC();
+  clangObjc.CollectMultipleMethodsInGlobalPool(clangSelector,
                                                objcMethods,
                                                /*InstanceFirst=*/true,
                                                /*CheckTheOther=*/false);
-  clangSema.CollectMultipleMethodsInGlobalPool(clangSelector,
+  clangObjc.CollectMultipleMethodsInGlobalPool(clangSelector,
                                                objcMethods,
                                                /*InstanceFirst=*/false,
                                                /*CheckTheOther=*/false);
@@ -4008,14 +4009,13 @@ StringRef ClangModuleUnit::getFilename() const {
     else
       return SinglePCH;
   }
-  if (const clang::FileEntry *F = clangModule->getASTFile())
-    if (!F->getName().empty())
-      return F->getName();
+  if (auto F = clangModule->getASTFile())
+    return F->getName();
   return StringRef();
 }
 
 StringRef ClangModuleUnit::getLoadedFilename() const {
-  if (const clang::FileEntry *F = clangModule->getASTFile())
+  if (auto F = clangModule->getASTFile())
     return F->getName();
   return StringRef();
 }
@@ -5312,9 +5312,9 @@ static clang::CXXMethodDecl *synthesizeCxxBaseGetterAccessorMethod(
 
   // Returns the expression that accesses the base field from derived type.
   auto createFieldAccess = [&]() -> clang::Expr * {
-    auto *thisExpr = new (clangCtx)
-        clang::CXXThisExpr(clang::SourceLocation(), newMethod->getThisType(),
-                           /*IsImplicit=*/false);
+    auto *thisExpr = clang::CXXThisExpr::Create(
+        clangCtx, clang::SourceLocation(), newMethod->getThisType(),
+        /*IsImplicit=*/false);
     clang::QualType baseClassPtr = clangCtx.getRecordType(baseClass);
     baseClassPtr.addConst();
     baseClassPtr = clangCtx.getPointerType(baseClassPtr);
@@ -7886,7 +7886,7 @@ bool importer::requiresCPlusPlus(const clang::Module *module) {
   }
 
   return llvm::any_of(module->Requirements, [](clang::Module::Requirement req) {
-    return req.first == "cplusplus";
+    return req.FeatureName == "cplusplus";
   });
 }
 
diff --git a/lib/ClangImporter/ImportDecl.cpp b/lib/ClangImporter/ImportDecl.cpp
index 3e1827dcbd2ca..00a8b48e01d5c 100644
--- a/lib/ClangImporter/ImportDecl.cpp
+++ b/lib/ClangImporter/ImportDecl.cpp
@@ -59,6 +59,7 @@
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/Lookup.h"
 
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringExtras.h"
@@ -872,26 +873,6 @@ static bool areRecordFieldsComplete(const clang::CXXRecordDecl *decl) {
 }
 
 namespace {
-  /// Customized llvm::DenseMapInfo for storing borrowed APSInts.
-  struct APSIntRefDenseMapInfo {
-    static inline const llvm::APSInt *getEmptyKey() {
-      return llvm::DenseMapInfo<const llvm::APSInt *>::getEmptyKey();
-    }
-    static inline const llvm::APSInt *getTombstoneKey() {
-      return llvm::DenseMapInfo<const llvm::APSInt *>::getTombstoneKey();
-    }
-    static unsigned getHashValue(const llvm::APSInt *ptrVal) {
-      assert(ptrVal != getEmptyKey() && ptrVal != getTombstoneKey());
-      return llvm::hash_value(*ptrVal);
-    }
-    static bool isEqual(const llvm::APSInt *lhs, const llvm::APSInt *rhs) {
-      if (lhs == rhs) return true;
-      if (lhs == getEmptyKey() || rhs == getEmptyKey()) return false;
-      if (lhs == getTombstoneKey() || rhs == getTombstoneKey()) return false;
-      return *lhs == *rhs;
-    }
-  };
-
   /// Search the member tables for this class and its superclasses and try to
   /// identify the nearest VarDecl that serves as a base for an override.  We
   /// have to do this ourselves because Objective-C has no semantic notion of
@@ -1861,17 +1842,16 @@ namespace {
         break;
       }
 
-      llvm::SmallDenseMap<const llvm::APSInt *,
+      llvm::SmallDenseMap<llvm::APSInt,
                           PointerUnion<const clang::EnumConstantDecl *,
-                                       EnumElementDecl *>, 8,
-                          APSIntRefDenseMapInfo> canonicalEnumConstants;
+                                       EnumElementDecl *>, 8> canonicalEnumConstants;
 
       if (enumKind == EnumKind::NonFrozenEnum ||
           enumKind == EnumKind::FrozenEnum) {
         for (auto constant : decl->enumerators()) {
           if (Impl.isUnavailableInSwift(constant))
             continue;
-          canonicalEnumConstants.insert({&constant->getInitVal(), constant});
+          canonicalEnumConstants.insert({constant->getInitVal(), constant});
         }
       }
 
@@ -1932,7 +1912,7 @@ namespace {
         case EnumKind::NonFrozenEnum:
         case EnumKind::FrozenEnum: {
           auto canonicalCaseIter =
-            canonicalEnumConstants.find(&constant->getInitVal());
+            canonicalEnumConstants.find(constant->getInitVal());
 
           if (canonicalCaseIter == canonicalEnumConstants.end()) {
             // Unavailable declarations get no special treatment.
@@ -2256,7 +2236,7 @@ namespace {
 
           // Unnamed bitfields are just for padding and should not
           // inhibit creation of a memberwise initializer.
-          if (field->isUnnamedBitfield()) {
+          if (field->isUnnamedBitField()) {
             hasUnreferenceableStorage = true;
             continue;
           }
@@ -3375,7 +3355,7 @@ namespace {
                    d->getName() == "cos" || d->getName() == "exit";
           return false;
         };
-        
+
         if (clang::Module *owningModule = decl->getOwningModule();
             owningModule && importer::isCxxStdModule(owningModule)) {
           if (isAlternativeCStdlibFunctionFromTextualHeader(decl)) {
@@ -3383,7 +3363,7 @@ namespace {
           }
 
           auto &sourceManager = Impl.getClangPreprocessor().getSourceManager();
-          if (const auto file = sourceManager.getFileEntryForID(
+          if (auto file = sourceManager.getFileEntryRefForID(
                   sourceManager.getFileID(decl->getLocation()))) {
             auto filename = file->getName();
             if ((file->getDir() == owningModule->Directory) &&
@@ -3461,8 +3441,9 @@ namespace {
             // parameters when the function template is instantiated, so do not
             // import the function template if the template parameter has
             // dependent default value.
-            auto defaultArgumentType = templateTypeParam->getDefaultArgument();
-            if (defaultArgumentType->isDependentType())
+            auto &defaultArgument =
+                templateTypeParam->getDefaultArgument().getArgument();
+            if (defaultArgument.isDependent())
               return nullptr;
             continue;
           }
@@ -3768,7 +3749,7 @@ namespace {
             // this method would get sliced away, and an invocation would get
             // dispatched statically. This is fine because it matches the C++
             // behavior.
-            if (decl->isPure()) {
+            if (decl->isPureVirtual()) {
               // If this is a pure virtual method, we won't have any
               // implementation of it to invoke.
               Impl.markUnavailable(funcDecl,
@@ -4586,7 +4567,8 @@ namespace {
                                                : getOverridableAccessLevel(dc));
 
       // Optional methods in protocols.
-      if (decl->getImplementationControl() == clang::ObjCMethodDecl::Optional &&
+      if (decl->getImplementationControl() ==
+              clang::ObjCImplementationControl::Optional &&
           isa<ProtocolDecl>(dc))
         result->getAttrs().add(new (Impl.SwiftContext)
                                       OptionalAttr(/*implicit*/false));
@@ -5495,8 +5477,9 @@ namespace {
       if (decl->hasAttr<clang::IBOutletAttr>())
         result->getAttrs().add(
             new (Impl.SwiftContext) IBOutletAttr(/*IsImplicit=*/false));
-      if (decl->getPropertyImplementation() == clang::ObjCPropertyDecl::Optional
-          && isa<ProtocolDecl>(dc) &&
+      if (decl->getPropertyImplementation() ==
+              clang::ObjCPropertyDecl::Optional &&
+          isa<ProtocolDecl>(dc) &&
           !result->getAttrs().hasAttribute<OptionalAttr>())
         result->getAttrs().add(new (Impl.SwiftContext)
                                       OptionalAttr(/*implicit*/false));
@@ -5593,12 +5576,6 @@ namespace {
       return nullptr;
     }
 
-    Decl *VisitClassScopeFunctionSpecializationDecl(
-                 const clang::ClassScopeFunctionSpecializationDecl *decl) {
-      // Note: templates are not imported.
-      return nullptr;
-    }
-
     Decl *VisitImportDecl(const clang::ImportDecl *decl) {
       // Transitive module imports are not handled at the declaration level.
       // Rather, they are understood from the module itself.
@@ -7026,7 +7003,7 @@ SwiftDeclConverter::importSubscript(Decl *decl,
 
   // Find the counterpart.
   bool optionalMethods = (objcMethod->getImplementationControl() ==
-                          clang::ObjCMethodDecl::Optional);
+                          clang::ObjCImplementationControl::Optional);
 
   if (auto *counterpart = findCounterpart(counterpartSelector)) {
     const clang::ObjCMethodDecl *counterpartMethod = nullptr;
@@ -7040,7 +7017,7 @@ SwiftDeclConverter::importSubscript(Decl *decl,
       counterpartMethod = cast<clang::ObjCMethodDecl>(importedFrom);
       if (optionalMethods)
         optionalMethods = (counterpartMethod->getImplementationControl() ==
-                           clang::ObjCMethodDecl::Optional);
+                           clang::ObjCImplementationControl::Optional);
     }
 
     assert(!counterpart || !counterpart->isStatic());
@@ -8558,12 +8535,12 @@ ClangImporter::Implementation::importDeclImpl(const clang::NamedDecl *ClangDecl,
     if (auto clangProto
           = dyn_cast<clang::ObjCProtocolDecl>(ClangDecl->getDeclContext())) {
       if (auto method = dyn_cast<clang::ObjCMethodDecl>(ClangDecl)) {
-        if (method->getImplementationControl()
-              == clang::ObjCMethodDecl::Required)
+        if (method->getImplementationControl() ==
+            clang::ObjCImplementationControl::Required)
           hasMissingRequiredMember = true;
       } else if (auto prop = dyn_cast<clang::ObjCPropertyDecl>(ClangDecl)) {
-        if (prop->getPropertyImplementation()
-              == clang::ObjCPropertyDecl::Required)
+        if (prop->getPropertyImplementation() ==
+            clang::ObjCPropertyDecl::Required)
           hasMissingRequiredMember = true;
       }
 
@@ -9209,7 +9186,7 @@ void ClangImporter::Implementation::loadAllMembersOfRecordDecl(
 
     // Currently, we don't import unnamed bitfields.
     if (isa<clang::FieldDecl>(m) &&
-        cast<clang::FieldDecl>(m)->isUnnamedBitfield())
+        cast<clang::FieldDecl>(m)->isUnnamedBitField())
       continue;
 
     // Make sure we always pull in record fields. Everything else had better
diff --git a/lib/ClangImporter/ImportEnumInfo.cpp b/lib/ClangImporter/ImportEnumInfo.cpp
index 972f9a641bb19..c1622b2497b80 100644
--- a/lib/ClangImporter/ImportEnumInfo.cpp
+++ b/lib/ClangImporter/ImportEnumInfo.cpp
@@ -108,11 +108,11 @@ void EnumInfo::classifyEnum(const clang::EnumDecl *decl,
 
   // If API notes have /removed/ a FlagEnum or EnumExtensibility attribute,
   // then we don't need to check the macros.
-  for (auto *attr : decl->specific_attrs<clang::SwiftVersionedAttr>()) {
+  for (auto *attr : decl->specific_attrs<clang::SwiftVersionedAdditionAttr>()) {
     if (!attr->getIsReplacedByActive())
       continue;
-    if (isa<clang::FlagEnumAttr>(attr->getAttrToAdd()) ||
-        isa<clang::EnumExtensibilityAttr>(attr->getAttrToAdd())) {
+    if (isa<clang::FlagEnumAttr>(attr->getAdditionalAttr()) ||
+        isa<clang::EnumExtensibilityAttr>(attr->getAdditionalAttr())) {
       kind = EnumKind::Unknown;
       return;
     }
diff --git a/lib/ClangImporter/ImportMacro.cpp b/lib/ClangImporter/ImportMacro.cpp
index 2a194468f7a22..32a1346d2b7ad 100644
--- a/lib/ClangImporter/ImportMacro.cpp
+++ b/lib/ClangImporter/ImportMacro.cpp
@@ -399,10 +399,9 @@ static ValueDecl *importMacro(ClangImporter::Implementation &impl,
 
   // Handle tokens starting with a type cast
   bool castTypeIsId = false;
-  if (numTokens > 3 &&
-      tokenI[0].is(clang::tok::l_paren) &&
+  if (numTokens > 3 && tokenI[0].is(clang::tok::l_paren) &&
       (tokenI[1].is(clang::tok::identifier) ||
-        impl.getClangSema().isSimpleTypeSpecifier(tokenI[1].getKind())) &&
+       tokenI[1].isSimpleTypeSpecifier(impl.getClangSema().getLangOpts())) &&
       tokenI[2].is(clang::tok::r_paren)) {
     if (!castType.isNull()) {
       // this is a nested cast
diff --git a/lib/ClangImporter/ImportName.cpp b/lib/ClangImporter/ImportName.cpp
index 06d5c9329dfb5..b0ab9cb972064 100644
--- a/lib/ClangImporter/ImportName.cpp
+++ b/lib/ClangImporter/ImportName.cpp
@@ -548,7 +548,7 @@ struct AnySwiftNameAttr {
   }
 };
 
-/// Aggregate struct for the common members of clang::SwiftVersionedAttr and
+/// Aggregate struct for the common members of clang::SwiftVersionedAdditionAttr and
 /// clang::SwiftVersionedRemovalAttr.
 ///
 /// For a SwiftVersionedRemovalAttr, the Attr member will be null.
@@ -671,8 +671,8 @@ findSwiftNameAttr(const clang::Decl *decl, ImportNameVersion version) {
     for (auto *attr : decl->attrs()) {
       VersionedSwiftNameInfo info;
 
-      if (auto *versionedAttr = dyn_cast<clang::SwiftVersionedAttr>(attr)) {
-        auto added = decodeAttr(versionedAttr->getAttrToAdd());
+      if (auto *versionedAttr = dyn_cast<clang::SwiftVersionedAdditionAttr>(attr)) {
+        auto added = decodeAttr(versionedAttr->getAdditionalAttr());
         if (!added)
           continue;
 
@@ -1430,7 +1430,7 @@ bool NameImporter::hasErrorMethodNameCollision(
   unsigned numArgs = selector.getNumArgs();
   assert(numArgs > 0);
 
-  SmallVector<clang::IdentifierInfo *, 4> chunks;
+  SmallVector<const clang::IdentifierInfo *, 4> chunks;
   for (unsigned i = 0, e = selector.getNumArgs(); i != e; ++i) {
     chunks.push_back(selector.getIdentifierInfoForSlot(i));
   }
diff --git a/lib/ClangImporter/ImportType.cpp b/lib/ClangImporter/ImportType.cpp
index a9e55610d5d2e..1426eee0ca03b 100644
--- a/lib/ClangImporter/ImportType.cpp
+++ b/lib/ClangImporter/ImportType.cpp
@@ -283,6 +283,7 @@ namespace {
       case clang::BuiltinType::Overload:
       case clang::BuiltinType::PseudoObject:
       case clang::BuiltinType::UnknownAny:
+      case clang::BuiltinType::UnresolvedTemplate:
         return Type();
 
       // FIXME: Types that can be mapped, but aren't yet.
@@ -381,7 +382,7 @@ namespace {
         return Type();
 
       // OpenMP types that don't have Swift equivalents.
-      case clang::BuiltinType::OMPArraySection:
+      case clang::BuiltinType::ArraySection:
       case clang::BuiltinType::OMPArrayShaping:
       case clang::BuiltinType::OMPIterator:
         return Type();
@@ -450,6 +451,17 @@ namespace {
       return Type();
     }
 
+    ImportResult VisitCountAttributedType(
+        const clang::CountAttributedType *type) {
+      // CountAttributedType is a clang type representing a pointer with
+      // a "counted_by" type attribute. For now, we don't import these
+      // into Swift.
+      // In the future we could do something more clever (such as trying to
+      // import as an Array where possible) or less clever (such as importing
+      // as the desugared, underlying pointer type).
+      return Type();
+    }
+
     ImportResult VisitMemberPointerType(const clang::MemberPointerType *type) {
       return Type();
     }
@@ -1285,6 +1297,10 @@ namespace {
 
       return { importedType, ImportHint::ObjCPointer };
     }
+
+    ImportResult VisitPackIndexingType(const clang::PackIndexingType *type) {
+      return Type();
+    }
   };
 } // end anonymous namespace
 
diff --git a/lib/ClangImporter/Serializability.cpp b/lib/ClangImporter/Serializability.cpp
index bbb8668652ac2..d59863b06c5c3 100644
--- a/lib/ClangImporter/Serializability.cpp
+++ b/lib/ClangImporter/Serializability.cpp
@@ -317,6 +317,18 @@ namespace {
     }
 
     void writeAttr(const clang::Attr *attr) {}
+
+    // CountAttributedType is a clang type representing a pointer with
+    // a "counted_by" type attribute and DynamicRangePointerType
+    // is representing a "__ended_by" type attribute.
+    // TypeCoupledDeclRefInfo is used to hold information of a declaration
+    // referenced from an expression argument of "__counted_by(expr)" or
+    // "__ended_by(expr)".
+    // Leave it non-serializable for now as we currently don't import
+    // these types into Swift.
+    void writeTypeCoupledDeclRefInfo(clang::TypeCoupledDeclRefInfo info) {
+      llvm_unreachable("TypeCoupledDeclRefInfo shouldn't be reached from swift");
+    }
   };
 }
 
diff --git a/lib/ClangImporter/SwiftDeclSynthesizer.cpp b/lib/ClangImporter/SwiftDeclSynthesizer.cpp
index b8d6614bd11c9..fbbf5fc11fff9 100644
--- a/lib/ClangImporter/SwiftDeclSynthesizer.cpp
+++ b/lib/ClangImporter/SwiftDeclSynthesizer.cpp
@@ -2132,8 +2132,9 @@ clang::CXXMethodDecl *SwiftDeclSynthesizer::synthesizeCXXForwardingMethod(
   auto diagState = clangSema.DelayedDiagnostics.push(diagPool);
 
   // Construct the method's body.
-  clang::Expr *thisExpr = new (clangCtx) clang::CXXThisExpr(
-      clang::SourceLocation(), newMethod->getThisType(), /*IsImplicit=*/false);
+  clang::Expr *thisExpr = clang::CXXThisExpr::Create(
+      clangCtx, clang::SourceLocation(), newMethod->getThisType(),
+      /*IsImplicit=*/false);
   if (castThisToNonConstThis) {
     auto baseClassPtr =
         clangCtx.getPointerType(clangCtx.getRecordType(derivedClass));
diff --git a/lib/ClangImporter/SwiftLookupTable.cpp b/lib/ClangImporter/SwiftLookupTable.cpp
index be60f796c0032..c62466e621ae0 100644
--- a/lib/ClangImporter/SwiftLookupTable.cpp
+++ b/lib/ClangImporter/SwiftLookupTable.cpp
@@ -51,6 +51,12 @@ static bool matchesExistingDecl(clang::Decl *decl, clang::Decl *existingDecl) {
   return false;
 }
 
+template <typename value_type, typename CharT>
+[[nodiscard]] static inline value_type readNext(const CharT *&memory) {
+  return llvm::support::endian::readNext<value_type, llvm::endianness::little,
+                                         llvm::support::unaligned>(memory);
+}
+
 namespace {
   class BaseNameToEntitiesTableReaderInfo;
   class GlobalsAsMembersTableReaderInfo;
@@ -827,9 +833,9 @@ ArrayRef<clang::ObjCCategoryDecl *> SwiftLookupTable::categories() {
 
   // Map categories known to the reader.
   for (auto declID : Reader->categories()) {
-    auto category =
-      cast_or_null<clang::ObjCCategoryDecl>(
-        Reader->getASTReader().GetLocalDecl(Reader->getModuleFile(), declID));
+    auto category = cast_or_null<clang::ObjCCategoryDecl>(
+        Reader->getASTReader().GetLocalDecl(Reader->getModuleFile(),
+                                            clang::LocalDeclID(declID)));
     if (category)
       Categories.push_back(category);
 
@@ -924,10 +930,10 @@ static void printStoredContext(SwiftLookupTable::StoredContext context,
   }
 }
 
-static uint32_t getEncodedDeclID(uint64_t entry) {
-  assert(SwiftLookupTable::isSerializationIDEntry(entry)); 
+static clang::LocalDeclID getEncodedDeclID(uint64_t entry) {
+  assert(SwiftLookupTable::isSerializationIDEntry(entry));
   assert(SwiftLookupTable::isDeclEntry(entry));
-  return entry >> 2;
+  return clang::LocalDeclID(entry >> 2);
 }
 
 namespace {
@@ -949,7 +955,7 @@ static void printStoredEntry(const SwiftLookupTable *table, uint64_t entry,
                              llvm::raw_ostream &out) {
   if (SwiftLookupTable::isSerializationIDEntry(entry)) {
     if (SwiftLookupTable::isDeclEntry(entry)) {
-      llvm::errs() << "decl ID #" << getEncodedDeclID(entry);
+      llvm::errs() << "decl ID #" << getEncodedDeclID(entry).get();
     } else {
       LocalMacroIDs macroIDs = getEncodedModuleMacroIDs(entry);
       if (macroIDs.moduleID == 0) {
@@ -1146,14 +1152,14 @@ namespace {
         dataLength += (sizeof(uint64_t) * entry.DeclsOrMacros.size());
       }
 
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint16_t>(keyLength);
       writer.write<uint32_t>(dataLength);
       return { keyLength, dataLength };
     }
 
     void EmitKey(raw_ostream &out, key_type_ref key, unsigned len) {
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint8_t>((uint8_t)key.Kind);
       if (key.Kind == swift::DeclBaseName::Kind::Normal)
         writer.OS << key.Name;
@@ -1161,7 +1167,7 @@ namespace {
 
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
 
       // # of entries
       writer.write<uint16_t>(data.size());
@@ -1184,7 +1190,7 @@ namespace {
           uint64_t id;
           auto mappedEntry = Table.mapStored(entry, isModule);
           if (auto *decl = mappedEntry.dyn_cast<clang::NamedDecl *>()) {
-            id = (Writer.getDeclID(decl) << 2) | 0x02;
+            id = (Writer.getDeclID(decl).get() << 2) | 0x02;
           } else if (auto *macro = mappedEntry.dyn_cast<clang::MacroInfo *>()) {
             id = static_cast<uint64_t>(Writer.getMacroID(macro)) << 32;
             id |= 0x02 | 0x01;
@@ -1240,14 +1246,14 @@ namespace {
         sizeof(uint16_t) + sizeof(uint64_t) * data.size();
       assert(dataLength == static_cast<uint32_t>(dataLength));
 
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint16_t>(keyLength);
       writer.write<uint32_t>(dataLength);
       return { keyLength, dataLength };
     }
 
     void EmitKey(raw_ostream &out, key_type_ref key, unsigned len) {
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint8_t>(static_cast<unsigned>(key.first) - 2);
       if (SwiftLookupTable::contextRequiresName(key.first))
         out << key.second;
@@ -1255,7 +1261,7 @@ namespace {
 
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
 
       // # of entries
       writer.write<uint16_t>(data.size());
@@ -1266,7 +1272,7 @@ namespace {
         uint64_t id;
         auto mappedEntry = Table.mapStored(entry, isModule);
         if (auto *decl = mappedEntry.dyn_cast<clang::NamedDecl *>()) {
-          id = (Writer.getDeclID(decl) << 2) | 0x02;
+          id = (Writer.getDeclID(decl).get() << 2) | 0x02;
         } else if (auto *macro = mappedEntry.dyn_cast<clang::MacroInfo *>()) {
           id = static_cast<uint64_t>(Writer.getMacroID(macro)) << 32;
           id |= 0x02 | 0x01;
@@ -1314,7 +1320,7 @@ void SwiftLookupTableWriter::writeExtensionContents(
 
       llvm::raw_svector_ostream blobStream(hashTableBlob);
       // Make sure that no bucket is at offset 0
-      endian::write<uint32_t>(blobStream, 0, little);
+      endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
       tableOffset = generator.Emit(blobStream, info);
     }
 
@@ -1326,7 +1332,7 @@ void SwiftLookupTableWriter::writeExtensionContents(
   if (!table.Categories.empty()) {
     SmallVector<clang::serialization::DeclID, 4> categoryIDs;
     for (auto category : table.Categories) {
-      categoryIDs.push_back(Writer.getDeclID(category));
+      categoryIDs.push_back(Writer.getDeclID(category).get());
     }
 
     StringRef blob(reinterpret_cast<const char *>(categoryIDs.data()),
@@ -1356,7 +1362,7 @@ void SwiftLookupTableWriter::writeExtensionContents(
 
         llvm::raw_svector_ostream blobStream(hashTableBlob);
         // Make sure that no bucket is at offset 0
-        endian::write<uint32_t>(blobStream, 0, little);
+        endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
         tableOffset = generator.Emit(blobStream, info);
       }
 
@@ -1386,7 +1392,7 @@ void SwiftLookupTableWriter::writeExtensionContents(
 
       llvm::raw_svector_ostream blobStream(hashTableBlob);
       // Make sure that no bucket is at offset 0
-      endian::write<uint32_t>(blobStream, 0, little);
+      endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
       tableOffset = generator.Emit(blobStream, info);
     }
 
@@ -1423,13 +1429,13 @@ namespace {
 
     static std::pair<unsigned, unsigned>
     ReadKeyDataLength(const uint8_t *&data) {
-      unsigned keyLength = endian::readNext<uint16_t, little, unaligned>(data);
-      unsigned dataLength = endian::readNext<uint32_t, little, unaligned>(data);
+      unsigned keyLength = readNext<uint16_t>(data);
+      unsigned dataLength = readNext<uint32_t>(data);
       return { keyLength, dataLength };
     }
 
     static internal_key_type ReadKey(const uint8_t *data, unsigned length) {
-      uint8_t kind = endian::readNext<uint8_t, little, unaligned>(data);
+      uint8_t kind = readNext<uint8_t>(data);
       switch (kind) {
       case (uint8_t)DeclBaseName::Kind::Normal: {
         StringRef str(reinterpret_cast<const char *>(data),
@@ -1452,7 +1458,7 @@ namespace {
       data_type result;
 
       // # of entries.
-      unsigned numEntries = endian::readNext<uint16_t, little, unaligned>(data);
+      unsigned numEntries = readNext<uint16_t>(data);
       result.reserve(numEntries);
 
       // Read all of the entries.
@@ -1461,19 +1467,17 @@ namespace {
 
         // Read the context.
         entry.Context.first =
-          static_cast<SwiftLookupTable::ContextKind>(
-            endian::readNext<uint8_t, little, unaligned>(data));
+            static_cast<SwiftLookupTable::ContextKind>(readNext<uint8_t>(data));
         if (SwiftLookupTable::contextRequiresName(entry.Context.first)) {
-          uint16_t length = endian::readNext<uint16_t, little, unaligned>(data);
+          uint16_t length = readNext<uint16_t>(data);
           entry.Context.second = StringRef((const char *)data, length);
           data += length;
         }
 
         // Read the declarations and macros.
-        unsigned numDeclsOrMacros =
-          endian::readNext<uint16_t, little, unaligned>(data);
+        unsigned numDeclsOrMacros = readNext<uint16_t>(data);
         while (numDeclsOrMacros--) {
-          auto id = endian::readNext<uint64_t, little, unaligned>(data);
+          auto id = readNext<uint64_t>(data);
           entry.DeclsOrMacros.push_back(id);
         }
 
@@ -1511,8 +1515,8 @@ namespace {
 
     static std::pair<unsigned, unsigned>
     ReadKeyDataLength(const uint8_t *&data) {
-      unsigned keyLength = endian::readNext<uint16_t, little, unaligned>(data);
-      unsigned dataLength = endian::readNext<uint32_t, little, unaligned>(data);
+      unsigned keyLength = readNext<uint16_t>(data);
+      unsigned dataLength = readNext<uint32_t>(data);
       return { keyLength, dataLength };
     }
 
@@ -1527,12 +1531,12 @@ namespace {
       data_type result;
 
       // # of entries.
-      unsigned numEntries = endian::readNext<uint16_t, little, unaligned>(data);
+      unsigned numEntries = readNext<uint16_t>(data);
       result.reserve(numEntries);
 
       // Read all of the entries.
       while (numEntries--) {
-        auto id = endian::readNext<uint64_t, little, unaligned>(data);
+        auto id = readNext<uint64_t>(data);
         result.push_back(id);
       }
 
@@ -1551,7 +1555,7 @@ clang::NamedDecl *SwiftLookupTable::mapStoredDecl(uint64_t &entry) {
 
   // Otherwise, resolve the declaration.
   assert(Reader && "Cannot resolve the declaration without a reader");
-  uint32_t declID = getEncodedDeclID(entry);
+  clang::LocalDeclID declID = getEncodedDeclID(entry);
   auto decl = cast_or_null<clang::NamedDecl>(
                 Reader->getASTReader().GetLocalDecl(Reader->getModuleFile(),
                                                     declID));
diff --git a/lib/Driver/Compilation.cpp b/lib/Driver/Compilation.cpp
index ee4cfcc678bd4..63dd11bdbba5b 100644
--- a/lib/Driver/Compilation.cpp
+++ b/lib/Driver/Compilation.cpp
@@ -731,7 +731,7 @@ namespace driver {
     /// Create \c NumberOfParallelCommands batches and assign each job to a
     /// batch either filling each partition in order or, if seeded with a
     /// nonzero value, pseudo-randomly (but deterministically and nearly-evenly).
-    void partitionIntoBatches(std::vector<const Job *> Batchable,
+    void partitionIntoBatches(const llvm::SmallVectorImpl<const Job *> &Batchable,
                               BatchPartition &Partition) {
       if (Comp.getShowJobLifecycle()) {
         llvm::outs() << "Found " << Batchable.size() << " batchable jobs\n";
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index 49dfb4707f8c9..a019722698e61 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -249,7 +249,7 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
   }
 
   inputArgs.AddAllArgs(arguments, options::OPT_I);
-  inputArgs.AddAllArgs(arguments, options::OPT_F, options::OPT_Fsystem);
+  inputArgs.addAllArgs(arguments, {options::OPT_F, options::OPT_Fsystem});
   inputArgs.AddAllArgs(arguments, options::OPT_vfsoverlay);
 
   inputArgs.AddLastArg(arguments, options::OPT_AssertConfig);
@@ -305,8 +305,8 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
   inputArgs.AddLastArg(arguments, options::OPT_profile_generate);
   inputArgs.AddLastArg(arguments, options::OPT_profile_use);
   inputArgs.AddLastArg(arguments, options::OPT_profile_coverage_mapping);
-  inputArgs.AddAllArgs(arguments, options::OPT_warnings_as_errors,
-                       options::OPT_no_warnings_as_errors);
+  inputArgs.addAllArgs(arguments, {options::OPT_warnings_as_errors,
+                                   options::OPT_no_warnings_as_errors});
   inputArgs.AddLastArg(arguments, options::OPT_sanitize_EQ);
   inputArgs.AddLastArg(arguments, options::OPT_sanitize_recover_EQ);
   inputArgs.AddLastArg(arguments,
@@ -349,9 +349,9 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
   inputArgs.AddAllArgs(arguments, options::OPT_D);
 
   // Pass on file paths that should be remapped in debug info.
-  inputArgs.AddAllArgs(arguments, options::OPT_debug_prefix_map,
-                                  options::OPT_coverage_prefix_map,
-                                  options::OPT_file_prefix_map);
+  inputArgs.addAllArgs(arguments, {options::OPT_debug_prefix_map,
+                                   options::OPT_coverage_prefix_map,
+                                   options::OPT_file_prefix_map});
 
   std::string globalRemapping = getGlobalDebugPathRemapping();
   if (!globalRemapping.empty()) {
@@ -1312,7 +1312,8 @@ ToolChain::constructInvocation(const REPLJobAction &job,
   addRuntimeLibraryFlags(context.OI, FrontendArgs);
 
   context.Args.AddLastArg(FrontendArgs, options::OPT_import_objc_header);
-  context.Args.AddAllArgs(FrontendArgs, options::OPT_framework, options::OPT_L);
+  context.Args.addAllArgs(FrontendArgs,
+                          {options::OPT_framework, options::OPT_L});
   ToolChain::addLinkedLibArgs(context.Args, FrontendArgs);
 
   if (!useLLDB) {
diff --git a/lib/DriverTool/swift_cache_tool_main.cpp b/lib/DriverTool/swift_cache_tool_main.cpp
index 72096cc2045c0..f79d3a811333e 100644
--- a/lib/DriverTool/swift_cache_tool_main.cpp
+++ b/lib/DriverTool/swift_cache_tool_main.cpp
@@ -56,9 +56,7 @@ struct OutputEntry {
 
 enum ID {
   OPT_INVALID = 0, // This is not an option ID.
-#define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
-               HELPTEXT, METAVAR, VALUES)                                      \
-  OPT_##ID,
+#define OPTION(...) LLVM_MAKE_OPT_ID(__VA_ARGS__),
 #include "SwiftCacheToolOptions.inc"
   LastOption
 #undef OPTION
@@ -72,10 +70,7 @@ enum ID {
 #undef PREFIX
 
 static const OptTable::Info InfoTable[] = {
-#define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
-               HELPTEXT, METAVAR, VALUES)                                      \
-  {PREFIX, NAME,  HELPTEXT,    METAVAR,     OPT_##ID,  Option::KIND##Class,    \
-   PARAM,  FLAGS, OPT_##GROUP, OPT_##ALIAS, ALIASARGS, VALUES},
+#define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
 #include "SwiftCacheToolOptions.inc"
 #undef OPTION
 };
diff --git a/lib/DriverTool/swift_llvm_opt_main.cpp b/lib/DriverTool/swift_llvm_opt_main.cpp
index 17f7ae298d7a1..0acc283b74af5 100644
--- a/lib/DriverTool/swift_llvm_opt_main.cpp
+++ b/lib/DriverTool/swift_llvm_opt_main.cpp
@@ -114,11 +114,11 @@ static llvm::cl::opt<std::string> PassPipeline(
 //                               Helper Methods
 //===----------------------------------------------------------------------===//
 
-static llvm::CodeGenOpt::Level GetCodeGenOptLevel(const SwiftLLVMOptOptions &options) {
+static llvm::CodeGenOptLevel GetCodeGenOptLevel(const SwiftLLVMOptOptions &options) {
   // TODO: Is this the right thing to do here?
   if (options.Optimized)
-    return llvm::CodeGenOpt::Default;
-  return llvm::CodeGenOpt::None;
+    return llvm::CodeGenOptLevel::Default;
+  return llvm::CodeGenOptLevel::None;
 }
 
 // Returns the TargetMachine instance or zero if no triple is provided.
diff --git a/lib/Frontend/CachedDiagnostics.cpp b/lib/Frontend/CachedDiagnostics.cpp
index 069d2641ab8bb..180e639706b9b 100644
--- a/lib/Frontend/CachedDiagnostics.cpp
+++ b/lib/Frontend/CachedDiagnostics.cpp
@@ -828,7 +828,7 @@ CachingDiagnosticsProcessor::CachingDiagnosticsProcessor(
     // Write the uncompressed size in the end.
     if (!Compression.empty()) {
       llvm::raw_svector_ostream BufOS((SmallVectorImpl<char> &)Compression);
-      llvm::support::endian::Writer Writer(BufOS, llvm::support::little);
+      llvm::support::endian::Writer Writer(BufOS, llvm::endianness::little);
       Writer.write(uint32_t(Output.size()));
     }
 
@@ -876,7 +876,7 @@ CachingDiagnosticsProcessor::replayCachedDiagnostics(llvm::StringRef Buffer) {
           std::make_error_code(std::errc::message_size));
 
     uint32_t UncompressedSize =
-        llvm::support::endian::read<uint32_t, llvm::support::little>(
+        llvm::support::endian::read<uint32_t, llvm::endianness::little>(
             Buffer.data() + Buffer.size() - sizeof(uint32_t));
 
     StringRef CompressedData = Buffer.drop_back(sizeof(uint32_t));
diff --git a/lib/Frontend/CompileJobCacheKey.cpp b/lib/Frontend/CompileJobCacheKey.cpp
index 3aa065ff2577f..d6506abfee751 100644
--- a/lib/Frontend/CompileJobCacheKey.cpp
+++ b/lib/Frontend/CompileJobCacheKey.cpp
@@ -94,7 +94,8 @@ swift::createCompileJobCacheKeyForOutput(llvm::cas::ObjectStore &CAS,
 
   // CacheKey is the index of the producting input + the base key.
   // Encode the unsigned value as little endian in the field.
-  llvm::support::endian::write<uint32_t>(OS, InputIndex, llvm::support::little);
+  llvm::support::endian::write<uint32_t>(OS, InputIndex,
+                                         llvm::endianness::little);
 
   return CAS.storeFromString({BaseKey}, OS.str());
 }
diff --git a/lib/FrontendTool/FrontendTool.cpp b/lib/FrontendTool/FrontendTool.cpp
index ffb44e70c60d0..7e68844b61674 100644
--- a/lib/FrontendTool/FrontendTool.cpp
+++ b/lib/FrontendTool/FrontendTool.cpp
@@ -1263,9 +1263,9 @@ static bool printSwiftFeature(CompilerInstance &instance) {
     out << "}\n";
   };
   out << "  \"SupportedArguments\": [\n";
-#define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
-               HELPTEXT, METAVAR, VALUES)                                      \
-  printSingleFrontendOpt(*table, swift::options::OPT_##ID, out);
+#define OPTION(...)                                                            \
+  printSingleFrontendOpt(*table,                                               \
+                         swift::options::LLVM_MAKE_OPT_ID(__VA_ARGS__), out);
 #include "swift/Option/Options.inc"
 #undef OPTION
   out << "    \"LastOption\"\n";
diff --git a/lib/IDE/CodeCompletionCache.cpp b/lib/IDE/CodeCompletionCache.cpp
index 94820e1e828d6..2392f489b4779 100644
--- a/lib/IDE/CodeCompletionCache.cpp
+++ b/lib/IDE/CodeCompletionCache.cpp
@@ -303,8 +303,7 @@ static bool readCachedModule(llvm::MemoryBuffer *in,
 static void writeCachedModule(llvm::raw_ostream &out,
                               const CodeCompletionCache::Key &K,
                               CodeCompletionCache::Value &V) {
-  using namespace llvm::support;
-  endian::Writer LE(out, little);
+  llvm::support::endian::Writer LE(out, llvm::endianness::little);
 
   // HEADER
   // Metadata required for reading the completions.
@@ -320,7 +319,7 @@ static void writeCachedModule(llvm::raw_ostream &out,
     llvm::raw_svector_ostream OSS(scratch);
     OSS << K.ModuleFilename << "\0";
     OSS << K.ModuleName << "\0";
-    endian::Writer OSSLE(OSS, little);
+    llvm::support::endian::Writer OSSLE(OSS, llvm::endianness::little);
     OSSLE.write(K.AccessPath.size());
     for (StringRef p : K.AccessPath)
       OSS << p << "\0";
@@ -339,7 +338,7 @@ static void writeCachedModule(llvm::raw_ostream &out,
   llvm::raw_string_ostream results(results_);
   std::string chunks_;
   llvm::raw_string_ostream chunks(chunks_);
-  endian::Writer chunksLE(chunks, little);
+  llvm::support::endian::Writer chunksLE(chunks, llvm::endianness::little);
   std::string strings_;
   llvm::raw_string_ostream strings(strings_);
   llvm::StringMap<uint32_t> knownStrings;
@@ -355,7 +354,7 @@ static void writeCachedModule(llvm::raw_ostream &out,
       return found->second;
     }
     auto size = strings.tell();
-    endian::Writer LE(strings, little);
+    llvm::support::endian::Writer LE(strings, llvm::endianness::little);
     LE.write(static_cast<uint32_t>(str.size()));
     strings << str;
     knownStrings[str] = size;
@@ -380,7 +379,7 @@ static void writeCachedModule(llvm::raw_ostream &out,
     }
 
     auto size = types.tell();
-    endian::Writer LE(types, little);
+    llvm::support::endian::Writer LE(types, llvm::endianness::little);
     StringRef USR = type->getUSR();
     LE.write(static_cast<uint32_t>(USR.size()));
     types << USR;
@@ -413,7 +412,7 @@ static void writeCachedModule(llvm::raw_ostream &out,
 
   // RESULTS
   {
-    endian::Writer LE(results, little);
+    llvm::support::endian::Writer LE(results, llvm::endianness::little);
     for (const ContextFreeCodeCompletionResult *R : V.Results) {
       // FIXME: compress bitfield
       LE.write(static_cast<uint8_t>(R->getKind()));
diff --git a/lib/IRGen/GenCall.cpp b/lib/IRGen/GenCall.cpp
index e2a9f164e3373..1b0a37f123146 100644
--- a/lib/IRGen/GenCall.cpp
+++ b/lib/IRGen/GenCall.cpp
@@ -1027,6 +1027,10 @@ namespace {
         llvm_unreachable("ConstantMatrix type in ABI lowering?");
       }
 
+      case clang::Type::ArrayParameter:
+        llvm_unreachable("HLSL type in ABI lowering");
+
+
       case clang::Type::ConstantArray: {
         auto array = Ctx.getAsConstantArrayType(type);
         auto elt = Ctx.getCanonicalType(array->getElementType());
diff --git a/lib/IRGen/GenClass.cpp b/lib/IRGen/GenClass.cpp
index bb2635428c653..1fcdcdf40fa7e 100644
--- a/lib/IRGen/GenClass.cpp
+++ b/lib/IRGen/GenClass.cpp
@@ -1606,8 +1606,7 @@ namespace {
       std::optional<CanType> specializedGenericType;
       if ((specializedGenericType = getSpecializedGenericType()) && forMeta) {
         //     ClassMetadata *NonMetaClass;
-        b.addBitCast(IGM.getAddrOfTypeMetadata(*specializedGenericType),
-                     IGM.Int8PtrTy);
+        b.add(IGM.getAddrOfTypeMetadata(*specializedGenericType));
       } else {
         //     const uint8_t *IvarLayout;
         // GC/ARC layout.  TODO.
diff --git a/lib/IRGen/GenConstant.cpp b/lib/IRGen/GenConstant.cpp
index df18be6e11d99..4b5dd56178bad 100644
--- a/lib/IRGen/GenConstant.cpp
+++ b/lib/IRGen/GenConstant.cpp
@@ -30,7 +30,9 @@
 #include "DebugTypeInfo.h"
 #include "swift/IRGen/Linking.h"
 #include "swift/Basic/Range.h"
+#include "swift/Basic/Require.h"
 #include "swift/SIL/SILModule.h"
+#include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Support/BLAKE3.h"
 
 using namespace swift;
@@ -321,8 +323,16 @@ Explosion irgen::emitConstantValue(IRGenModule &IGM, SILValue operand,
       }
       case BuiltinValueKind::ZExtOrBitCast: {
         auto *val = emitConstantValue(IGM, args[0]).claimNextConstant();
-        return llvm::ConstantExpr::getZExtOrBitCast(val,
-                                                    IGM.getStorageType(BI->getType()));
+        auto storageTy = IGM.getStorageType(BI->getType());
+
+        if (val->getType() == storageTy)
+          return val;
+
+        auto *result = llvm::ConstantFoldCastOperand(
+            llvm::Instruction::ZExt, val, storageTy, IGM.DataLayout);
+        require(result != nullptr,
+                "couldn't constant fold initializer expression");
+        return result;
       }
       case BuiltinValueKind::StringObjectOr: {
         // It is a requirement that the or'd bits in the left argument are
diff --git a/lib/IRGen/GenCoverage.cpp b/lib/IRGen/GenCoverage.cpp
index 122d1229b0323..bf49a92e06015 100644
--- a/lib/IRGen/GenCoverage.cpp
+++ b/lib/IRGen/GenCoverage.cpp
@@ -42,7 +42,7 @@ using llvm::coverage::CovMapVersion;
 /// cannot pin our version, as it must remain in sync with the version Clang is
 /// using.
 /// Do not bump without at least filing a bug and pinging a coverage maintainer.
-static_assert(CovMapVersion::CurrentVersion == CovMapVersion::Version6,
+static_assert(CovMapVersion::CurrentVersion == CovMapVersion::Version7,
               "Coverage mapping emission needs updating");
 
 static std::string getInstrProfSection(IRGenModule &IGM,
diff --git a/lib/IRGen/GenDiffWitness.cpp b/lib/IRGen/GenDiffWitness.cpp
index d931647524fc3..488092757cc2e 100644
--- a/lib/IRGen/GenDiffWitness.cpp
+++ b/lib/IRGen/GenDiffWitness.cpp
@@ -39,10 +39,8 @@ void IRGenModule::emitSILDifferentiabilityWitness(
          "Differentiability witness definition should have JVP");
   assert(dw->getVJP() &&
          "Differentiability witness definition should have VJP");
-  diffWitnessContents.addBitCast(
-      getAddrOfSILFunction(dw->getJVP(), NotForDefinition), Int8PtrTy);
-  diffWitnessContents.addBitCast(
-      getAddrOfSILFunction(dw->getVJP(), NotForDefinition), Int8PtrTy);
+  diffWitnessContents.add(getAddrOfSILFunction(dw->getJVP(), NotForDefinition));
+  diffWitnessContents.add(getAddrOfSILFunction(dw->getVJP(), NotForDefinition));
   getAddrOfDifferentiabilityWitness(
       dw, diffWitnessContents.finishAndCreateFuture());
 }
diff --git a/lib/IRGen/GenOpaque.cpp b/lib/IRGen/GenOpaque.cpp
index 51cdc11bf7ec1..858ce581af7fc 100644
--- a/lib/IRGen/GenOpaque.cpp
+++ b/lib/IRGen/GenOpaque.cpp
@@ -623,8 +623,9 @@ StackAddress IRGenFunction::emitDynamicAlloca(llvm::Type *eltTy,
   // executed more than once).
   bool isInEntryBlock = (Builder.GetInsertBlock() == &*CurFn->begin());
   if (!isInEntryBlock) {
-    stackRestorePoint =
-        Builder.CreateIntrinsicCall(llvm::Intrinsic::stacksave, {}, "spsave");
+    stackRestorePoint = Builder.CreateIntrinsicCall(
+        llvm::Intrinsic::stacksave,
+        {IGM.DataLayout.getAllocaPtrType(IGM.getLLVMContext())}, {}, "spsave");
   }
 
   // Emit the dynamic alloca.
@@ -664,7 +665,8 @@ void IRGenFunction::emitDeallocateDynamicAlloca(StackAddress address,
   auto savedSP = address.getExtraInfo();
   if (savedSP == nullptr)
     return;
-  Builder.CreateIntrinsicCall(llvm::Intrinsic::stackrestore, savedSP);
+  Builder.CreateIntrinsicCall(llvm::Intrinsic::stackrestore,
+                              {savedSP->getType()}, {savedSP});
 }
 
 /// Emit a call to do an 'initializeArrayWithCopy' operation.
diff --git a/lib/IRGen/GenProto.cpp b/lib/IRGen/GenProto.cpp
index 02d9f10ef2374..05d2982c77fe1 100644
--- a/lib/IRGen/GenProto.cpp
+++ b/lib/IRGen/GenProto.cpp
@@ -1478,7 +1478,7 @@ class AccessorConformanceInfo : public ConformanceInfo {
       if (isRelative)
         Table.addRelativeAddress(descriptor);
       else
-        Table.addBitCast(descriptor, IGM.Int8PtrTy);
+        Table.add(descriptor);
     }
 
     /// A base protocol is witnessed by a pointer to the conformance
@@ -1514,7 +1514,7 @@ class AccessorConformanceInfo : public ConformanceInfo {
         Table.addRelativeAddress(baseWitness);
         return;
       } else if (baseWitness) {
-        Table.addBitCast(baseWitness, IGM.Int8PtrTy);
+        Table.add(baseWitness);
         return;
       }
 
diff --git a/lib/IRGen/IRGen.cpp b/lib/IRGen/IRGen.cpp
index 118a634d01509..1431b91f666c5 100644
--- a/lib/IRGen/IRGen.cpp
+++ b/lib/IRGen/IRGen.cpp
@@ -330,7 +330,7 @@ void swift::performLLVMOptimizations(const IRGenOptions &Opts,
     options.Atomic = bool(Opts.Sanitizers & SanitizerKind::Thread);
     PB.registerPipelineStartEPCallback(
         [options](ModulePassManager &MPM, OptimizationLevel level) {
-          MPM.addPass(InstrProfiling(options, false));
+           MPM.addPass(InstrProfilingLoweringPass(options, false));
         });
   }
   if (Opts.shouldOptimize()) {
@@ -662,8 +662,8 @@ bool swift::compileAndWriteLLVM(
     legacy::PassManager EmitPasses;
     CodeGenFileType FileType;
     FileType =
-        (opts.OutputKind == IRGenOutputKind::NativeAssembly ? CGFT_AssemblyFile
-                                                            : CGFT_ObjectFile);
+        (opts.OutputKind == IRGenOutputKind::NativeAssembly ? CodeGenFileType::AssemblyFile
+                                                            : CodeGenFileType::ObjectFile);
     EmitPasses.add(createTargetTransformInfoWrapperPass(
         targetMachine->getTargetIRAnalysis()));
 
@@ -861,9 +861,9 @@ static void setPointerAuthOptions(PointerAuthOptions &opts,
 
 std::unique_ptr<llvm::TargetMachine>
 swift::createTargetMachine(const IRGenOptions &Opts, ASTContext &Ctx) {
-  CodeGenOpt::Level OptLevel = Opts.shouldOptimize()
-                                   ? CodeGenOpt::Default // -Os
-                                   : CodeGenOpt::None;
+  CodeGenOptLevel OptLevel = Opts.shouldOptimize()
+                                   ? CodeGenOptLevel::Default // -Os
+                                   : CodeGenOptLevel::None;
 
   // Set up TargetOptions and create the target features string.
   TargetOptions TargetOpts;
diff --git a/lib/IRGen/IRGenDebugInfo.cpp b/lib/IRGen/IRGenDebugInfo.cpp
index d3a0cabb5f27b..77cccbbd99d72 100644
--- a/lib/IRGen/IRGenDebugInfo.cpp
+++ b/lib/IRGen/IRGenDebugInfo.cpp
@@ -3365,9 +3365,9 @@ struct DbgIntrinsicEmitter {
 
   ///
 
-  llvm::Instruction *insert(llvm::Value *Addr, llvm::DILocalVariable *VarInfo,
-                            llvm::DIExpression *Expr,
-                            const llvm::DILocation *DL) {
+  llvm::DbgInstPtr insert(llvm::Value *Addr, llvm::DILocalVariable *VarInfo,
+                          llvm::DIExpression *Expr,
+                          const llvm::DILocation *DL) {
     if (auto *Inst = InsertPt.dyn_cast<llvm::Instruction *>()) {
       return insert(Addr, VarInfo, Expr, DL, Inst);
     } else {
@@ -3376,10 +3376,10 @@ struct DbgIntrinsicEmitter {
     }
   }
 
-  llvm::Instruction *insert(llvm::Value *Addr, llvm::DILocalVariable *VarInfo,
-                            llvm::DIExpression *Expr,
-                            const llvm::DILocation *DL,
-                            llvm::Instruction *InsertBefore) {
+  llvm::DbgInstPtr insert(llvm::Value *Addr, llvm::DILocalVariable *VarInfo,
+                          llvm::DIExpression *Expr,
+                          const llvm::DILocation *DL,
+                          llvm::Instruction *InsertBefore) {
     if (ForceDbgDeclare == AddrDbgInstrKind::DbgDeclare)
       return DIBuilder.insertDeclare(Addr, VarInfo, Expr, DL, InsertBefore);
     Expr = llvm::DIExpression::append(Expr, llvm::dwarf::DW_OP_deref);
@@ -3387,10 +3387,10 @@ struct DbgIntrinsicEmitter {
                                             InsertBefore);
   }
 
-  llvm::Instruction *insert(llvm::Value *Addr, llvm::DILocalVariable *VarInfo,
-                            llvm::DIExpression *Expr,
-                            const llvm::DILocation *DL,
-                            llvm::BasicBlock *Block) {
+  llvm::DbgInstPtr insert(llvm::Value *Addr, llvm::DILocalVariable *VarInfo,
+                          llvm::DIExpression *Expr,
+                          const llvm::DILocation *DL,
+                          llvm::BasicBlock *Block) {
     if (ForceDbgDeclare == AddrDbgInstrKind::DbgDeclare)
       return DIBuilder.insertDeclare(Addr, VarInfo, Expr, DL, Block);
     Expr = llvm::DIExpression::append(Expr, llvm::dwarf::DW_OP_deref);
diff --git a/lib/IRGen/IRGenModule.cpp b/lib/IRGen/IRGenModule.cpp
index 0d9b66255f1ea..bd355ba40be1f 100644
--- a/lib/IRGen/IRGenModule.cpp
+++ b/lib/IRGen/IRGenModule.cpp
@@ -239,7 +239,7 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   Int32Ty = llvm::Type::getInt32Ty(getLLVMContext());
   Int32PtrTy = Int32Ty->getPointerTo();
   Int64Ty = llvm::Type::getInt64Ty(getLLVMContext());
-  Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
+  Int8PtrTy = PtrTy;
   Int8PtrPtrTy = Int8PtrTy->getPointerTo(0);
   SizeTy = DataLayout.getIntPtrType(getLLVMContext(), /*addrspace*/ 0);
 
diff --git a/lib/IRGen/IRGenModule.h b/lib/IRGen/IRGenModule.h
index 9b1e8bf8386d8..51a43e4ffd2cc 100644
--- a/lib/IRGen/IRGenModule.h
+++ b/lib/IRGen/IRGenModule.h
@@ -695,7 +695,7 @@ class IRGenModule {
   bool ShouldUseSwiftError;
 
   llvm::Type *VoidTy;                  /// void (usually {})
-  llvm::Type *PtrTy;                   /// ptr
+  llvm::PointerType *PtrTy;            /// ptr
   llvm::IntegerType *Int1Ty;           /// i1
   llvm::IntegerType *Int8Ty;           /// i8
   llvm::IntegerType *Int16Ty;          /// i16
diff --git a/lib/IRGen/IRGenSIL.cpp b/lib/IRGen/IRGenSIL.cpp
index 82c13597ef4ad..9e377c8feca9f 100644
--- a/lib/IRGen/IRGenSIL.cpp
+++ b/lib/IRGen/IRGenSIL.cpp
@@ -6451,8 +6451,6 @@ void IRGenSILFunction::visitBeginAccessInst(BeginAccessInst *access) {
   case SILAccessEnforcement::Signed: {
     auto &ti = getTypeInfo(access->getType());
     auto *sea = cast<StructElementAddrInst>(access->getOperand());
-    auto *Int64PtrTy = llvm::Type::getInt64PtrTy(IGM.getLLVMContext());
-    auto *Int64PtrPtrTy = Int64PtrTy->getPointerTo();
     if (access->getAccessKind() == SILAccessKind::Read) {
       // When we see a signed read access, generate code to:
       // authenticate the signed pointer if non-null, and store the
@@ -6460,19 +6458,17 @@ void IRGenSILFunction::visitBeginAccessInst(BeginAccessInst *access) {
       // of the access to this stack location.
       auto pointerAuthQual = sea->getField()->getPointerAuthQualifier();
       auto *pointerToSignedFptr = getLoweredAddress(sea).getAddress();
-      auto *pointerToIntPtr =
-          Builder.CreateBitCast(pointerToSignedFptr, Int64PtrPtrTy);
-      auto *signedFptr = Builder.CreateLoad(pointerToIntPtr, Int64PtrTy,
+      auto *signedFptr = Builder.CreateLoad(pointerToSignedFptr, IGM.PtrTy,
                                             IGM.getPointerAlignment());
 
       // Create a stack temporary.
       auto temp = ti.allocateStack(*this, access->getType(), "ptrauth.temp");
       auto *tempAddressToIntPtr =
-          Builder.CreateBitCast(temp.getAddressPointer(), Int64PtrPtrTy);
+          Builder.CreateBitCast(temp.getAddressPointer(), IGM.PtrTy);
 
       // Branch based on pointer is null or not.
       llvm::Value *cond = Builder.CreateICmpNE(
-          signedFptr, llvm::ConstantPointerNull::get(Int64PtrTy));
+          signedFptr, llvm::ConstantPointerNull::get(IGM.PtrTy));
       auto *resignNonNull = createBasicBlock("resign-nonnull");
       auto *resignNull = createBasicBlock("resign-null");
       auto *resignCont = createBasicBlock("resign-cont");
@@ -6605,23 +6601,17 @@ void IRGenSILFunction::visitEndAccessInst(EndAccessInst *i) {
     // access which is the shadow stack slot, sign the value if non-null and
     // write back to the struct field.
     auto *sea = cast<StructElementAddrInst>(access->getOperand());
-    auto *Int64PtrTy = llvm::Type::getInt64PtrTy(IGM.getLLVMContext());
-    auto *Int64PtrPtrTy = Int64PtrTy->getPointerTo();
     auto pointerAuthQual = cast<StructElementAddrInst>(access->getOperand())
                                ->getField()
                                ->getPointerAuthQualifier();
     auto *pointerToSignedFptr =
         getLoweredAddress(access->getOperand()).getAddress();
-    auto *pointerToIntPtr =
-        Builder.CreateBitCast(pointerToSignedFptr, Int64PtrPtrTy);
-    auto tempAddress = getLoweredAddress(access);
-    auto *tempAddressToIntPtr =
-        Builder.CreateBitCast(tempAddress.getAddress(), Int64PtrPtrTy);
-    auto *tempAddressValue = Builder.CreateLoad(tempAddressToIntPtr, Int64PtrTy,
+    auto tempAddress = getLoweredAddress(access).getAddress();
+    auto *tempAddressValue = Builder.CreateLoad(tempAddress, IGM.PtrTy,
                                                 IGM.getPointerAlignment());
     // Branch based on value is null or not.
     llvm::Value *cond = Builder.CreateICmpNE(
-        tempAddressValue, llvm::ConstantPointerNull::get(Int64PtrTy));
+        tempAddressValue, llvm::ConstantPointerNull::get(IGM.PtrTy));
     auto *resignNonNull = createBasicBlock("resign-nonnull");
     auto *resignNull = createBasicBlock("resign-null");
     auto *resignCont = createBasicBlock("resign-cont");
@@ -6636,18 +6626,18 @@ void IRGenSILFunction::visitEndAccessInst(EndAccessInst *i) {
         sea->getType().getOptionalObjectType().getAs<SILFunctionType>());
     auto oldAuthInfo = PointerAuthInfo::emit(
         *this, IGM.getOptions().PointerAuth.FunctionPointers,
-        tempAddress.getAddress(), entity);
+        tempAddress, entity);
     auto newAuthInfo =
         PointerAuthInfo::emit(*this, pointerAuthQual, pointerToSignedFptr);
     auto *signedFptr = emitPointerAuthResign(*this, tempAddressValue,
                                              oldAuthInfo, newAuthInfo);
-    Builder.CreateStore(signedFptr, pointerToIntPtr, IGM.getPointerAlignment());
+    Builder.CreateStore(signedFptr, pointerToSignedFptr, IGM.getPointerAlignment());
 
     Builder.CreateBr(resignCont);
 
     // If null, no need to resign
     Builder.emitBlock(resignNull);
-    Builder.CreateStore(tempAddressValue, pointerToIntPtr, IGM.getPointerAlignment());
+    Builder.CreateStore(tempAddressValue, pointerToSignedFptr, IGM.getPointerAlignment());
     Builder.CreateBr(resignCont);
 
     Builder.emitBlock(resignCont);
diff --git a/lib/Immediate/SwiftMaterializationUnit.cpp b/lib/Immediate/SwiftMaterializationUnit.cpp
index dcda3baf6c2ce..92a01bcb0d6c9 100644
--- a/lib/Immediate/SwiftMaterializationUnit.cpp
+++ b/lib/Immediate/SwiftMaterializationUnit.cpp
@@ -157,7 +157,7 @@ SwiftJIT::CreateLLJIT(CompilerInstance &CI) {
                   .setOptions(std::move(TargetOpt))
                   .setCPU(std::move(CPU))
                   .addFeatures(Features)
-                  .setCodeGenOptLevel(llvm::CodeGenOpt::Default);
+                  .setCodeGenOptLevel(llvm::CodeGenOptLevel::Default);
   auto J = llvm::orc::LLJITBuilder()
                .setJITTargetMachineBuilder(std::move(JTMB))
                .create();
diff --git a/lib/Index/IndexRecord.cpp b/lib/Index/IndexRecord.cpp
index c9d24d69b2e7f..e73d7fa7f94de 100644
--- a/lib/Index/IndexRecord.cpp
+++ b/lib/Index/IndexRecord.cpp
@@ -479,10 +479,13 @@ static void emitSymbolicInterfaceForClangModule(
     return;
   }
 
+  auto moduleRef = clangModule->getASTFile();
+  if (!moduleRef)
+    return;
+
   // Determine the output name for the symbolic interface file.
   clang::serialization::ModuleFile *ModFile =
-      clangCI.getASTReader()->getModuleManager().lookup(
-          clangModule->getASTFile());
+      clangCI.getASTReader()->getModuleManager().lookup(*moduleRef);
   assert(ModFile && "no module file loaded for module ?");
   SmallString<128> interfaceOutputPath = indexStorePath;
   appendSymbolicInterfaceToIndexStorePath(interfaceOutputPath);
@@ -631,7 +634,7 @@ static void addModuleDependencies(ArrayRef<ImportedModule> imports,
           modulePath = LFU->getSourceFilename();
         }
 
-        auto F = fileMgr.getFile(modulePath);
+        auto F = fileMgr.getFileRef(modulePath);
         if (!F)
           break;
 
@@ -850,17 +853,18 @@ emitDataForSwiftSerializedModule(ModuleDecl *module,
 
   IndexUnitWriter unitWriter(
       fileMgr, indexStorePath, "swift", swiftVersion, filename, moduleName,
-      /*MainFile=*/nullptr, isSystem, /*IsModuleUnit=*/true, isDebugCompilation,
+      /*MainFile=*/{}, isSystem, /*IsModuleUnit=*/true, isDebugCompilation,
       targetTriple, sysrootPath, clangRemapper, getModuleInfoFromOpaqueModule);
 
-  auto FE = fileMgr.getFile(filename);
-  for (auto &pair : records) {
-    std::string &recordFile = pair.first;
-    std::string &groupName = pair.second;
-    if (recordFile.empty())
-      continue;
-    clang::index::writer::OpaqueModule mod = &groupName;
-    unitWriter.addRecordFile(recordFile, *FE, isSystem, mod);
+  if (auto FE = fileMgr.getFileRef(filename)) {
+    for (auto &pair : records) {
+      std::string &recordFile = pair.first;
+      std::string &groupName = pair.second;
+      if (recordFile.empty())
+        continue;
+      clang::index::writer::OpaqueModule mod = &groupName;
+      unitWriter.addRecordFile(recordFile, *FE, isSystem, mod);
+    }
   }
 
   SmallVector<ImportedModule, 8> imports;
@@ -887,21 +891,25 @@ recordSourceFileUnit(SourceFile *primarySourceFile, StringRef indexUnitToken,
                      bool indexSystemModules, bool skipStdlib,
                      bool includeLocals, bool isDebugCompilation,
                      bool isExplicitModuleBuild, StringRef targetTriple,
-                     ArrayRef<const clang::FileEntry *> fileDependencies,
+                     ArrayRef<clang::FileEntryRef> fileDependencies,
                      const clang::CompilerInstance &clangCI,
                      const PathRemapper &pathRemapper,
                      DiagnosticEngine &diags) {
   auto &fileMgr = clangCI.getFileManager();
   auto *module = primarySourceFile->getParentModule();
   bool isSystem = module->isNonUserModule();
-  auto mainFile = fileMgr.getFile(primarySourceFile->getFilename());
   auto clangRemapper = pathRemapper.asClangPathRemapper();
+
+  auto mainFile = fileMgr.getFileRef(primarySourceFile->getFilename());
+  if (!mainFile)
+    return false;
+
   // FIXME: Get real values for the following.
   StringRef swiftVersion;
   StringRef sysrootPath = clangCI.getHeaderSearchOpts().Sysroot;
   IndexUnitWriter unitWriter(
       fileMgr, indexStorePath, "swift", swiftVersion, indexUnitToken,
-      module->getNameStr(), mainFile ? *mainFile : nullptr, isSystem,
+      module->getNameStr(), *mainFile, isSystem,
       /*isModuleUnit=*/false, isDebugCompilation, targetTriple, sysrootPath,
       clangRemapper, getModuleInfoFromOpaqueModule);
 
@@ -917,15 +925,16 @@ recordSourceFileUnit(SourceFile *primarySourceFile, StringRef indexUnitToken,
                         primarySourceFile);
 
   // File dependencies.
-  for (auto *F : fileDependencies)
+  for (auto F : fileDependencies)
     unitWriter.addFileDependency(F, /*FIXME:isSystem=*/false, /*Module=*/nullptr);
 
   recordSourceFile(primarySourceFile, indexStorePath, includeLocals, diags,
                    [&](StringRef recordFile, StringRef filename) {
-                     auto file = fileMgr.getFile(filename);
-                     unitWriter.addRecordFile(
-                         recordFile, file ? *file : nullptr,
-                         module->isNonUserModule(), /*Module=*/nullptr);
+                     if (auto file = fileMgr.getFileRef(filename)) {
+                       unitWriter.addRecordFile(
+                           recordFile, *file,
+                           module->isNonUserModule(), /*Module=*/nullptr);
+                     }
                    });
 
   std::string error;
@@ -983,24 +992,11 @@ bool index::indexAndRecord(SourceFile *primarySourceFile,
     return true;
   }
 
-  llvm::SetVector<const clang::FileEntry *> fileDependencies;
-  // FIXME: This is not desirable because:
-  // 1. It picks shim header files as file dependencies
-  // 2. Having all the other swift files of the module as file dependencies ends
-  //   up making all of them associated with all the other files as main files.
-  //   It's better to associate each swift file with the unit that recorded it
-  //   as the main one.
-  // Keeping the code in case we want to revisit.
-#if 0
-  auto *module = primarySourceFile->getParentModule();
-  collectFileDependencies(fileDependencies, dependencyTracker, module, fileMgr);
-#endif
-
   return recordSourceFileUnit(primarySourceFile, indexUnitToken,
                               indexStorePath, indexClangModules,
                               indexSystemModules, skipStdlib, includeLocals,
                               isDebugCompilation, isExplicitModuleBuild,
-                              targetTriple, fileDependencies.getArrayRef(),
+                              targetTriple, {},
                               clangCI, pathRemapper, diags);
 }
 
@@ -1027,19 +1023,6 @@ bool index::indexAndRecord(ModuleDecl *module,
     return true;
   }
 
-  // Add the current module's source files to the dependencies.
-  llvm::SetVector<const clang::FileEntry *> fileDependencies;
-  // FIXME: This is not desirable because:
-  // 1. It picks shim header files as file dependencies
-  // 2. Having all the other swift files of the module as file dependencies ends
-  //   up making all of them associated with all the other files as main files.
-  //   It's better to associate each swift file with the unit that recorded it
-  //   as the main one.
-  // Keeping the code in case we want to revisit.
-#if 0
-  collectFileDependencies(fileDependencies, dependencyTracker, module, fileMgr);
-#endif
-
   // Write a unit for each source file.
   unsigned unitIndex = 0;
   for (auto *F : module->getFiles()) {
@@ -1052,7 +1035,7 @@ bool index::indexAndRecord(ModuleDecl *module,
                                indexStorePath, indexClangModules,
                                indexSystemModules, skipStdlib, includeLocals,
                                isDebugCompilation, isExplicitModuleBuild,
-                               targetTriple, fileDependencies.getArrayRef(),
+                               targetTriple, {},
                                clangCI, pathRemapper, diags))
         return true;
       unitIndex += 1;
diff --git a/lib/LLVMPasses/LLVMMergeFunctions.cpp b/lib/LLVMPasses/LLVMMergeFunctions.cpp
index 831f3d3daf6e7..b7b3f2f66e276 100644
--- a/lib/LLVMPasses/LLVMMergeFunctions.cpp
+++ b/lib/LLVMPasses/LLVMMergeFunctions.cpp
@@ -31,31 +31,32 @@
 #include "swift/LLVMPasses/Passes.h"
 #include "clang/AST/StableHash.h"
 #include "clang/Basic/PointerAuthOptions.h"
-#include "llvm/Transforms/IPO.h"
-#include "llvm/Transforms/Utils/FunctionComparator.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/Hashing.h"
-#include "llvm/TargetParser/Triple.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
+#include "llvm/IR/GlobalPtrAuthInfo.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Operator.h"
+#include "llvm/IR/StructuralHash.h"
 #include "llvm/IR/ValueHandle.h"
 #include "llvm/IR/ValueMap.h"
-#include "llvm/IR/GlobalPtrAuthInfo.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/TargetParser/Triple.h"
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/Utils/FunctionComparator.h"
 #include <vector>
 
 using namespace llvm;
@@ -256,11 +257,12 @@ class SwiftMergeFunctions {
     FunctionEntry *First;
 
     /// A very cheap hash, used to early exit if functions do not match.
-    FunctionComparator::FunctionHash Hash;
+    llvm::IRHash Hash;
+
   public:
     // Note the hash is recalculated potentially multiple times, but it is cheap.
     EquivalenceClass(FunctionEntry *First)
-      : First(First), Hash(FunctionComparator::functionHash(*First->F)) {
+        : First(First), Hash(llvm::StructuralHash(*First->F)) {
       assert(!First->Next);
     }
   };
@@ -710,21 +712,18 @@ bool SwiftMergeFunctions::runOnModule(Module &M) {
 
   // All functions in the module, ordered by hash. Functions with a unique
   // hash value are easily eliminated.
-  std::vector<std::pair<FunctionComparator::FunctionHash, Function *>>
-    HashedFuncs;
+  std::vector<std::pair<IRHash, Function *>> HashedFuncs;
 
   for (Function &Func : M) {
     if (isEligibleFunction(&Func)) {
-      HashedFuncs.push_back({FunctionComparator::functionHash(Func), &Func});
+      HashedFuncs.push_back({llvm::StructuralHash(Func), &Func});
     }
   }
 
   std::stable_sort(
       HashedFuncs.begin(), HashedFuncs.end(),
-      [](const std::pair<FunctionComparator::FunctionHash, Function *> &a,
-         const std::pair<FunctionComparator::FunctionHash, Function *> &b) {
-        return a.first < b.first;
-      });
+      [](const std::pair<IRHash, Function *> &a,
+         const std::pair<IRHash, Function *> &b) { return a.first < b.first; });
 
   std::vector<FunctionEntry> FuncEntryStorage;
   FuncEntryStorage.reserve(HashedFuncs.size());
@@ -1079,6 +1078,7 @@ void SwiftMergeFunctions::mergeWithParams(const FunctionInfos &FInfos,
   Function *NewFunction = Function::Create(funcType,
                                            FirstF->getLinkage(),
                                            FirstF->getName() + "Tm");
+  NewFunction->setIsNewDbgInfoFormat(FirstF->IsNewDbgInfoFormat);
   NewFunction->copyAttributesFrom(FirstF);
   // NOTE: this function is not externally available, do ensure that we reset
   // the DLL storage
diff --git a/lib/Localization/LocalizationFormat.cpp b/lib/Localization/LocalizationFormat.cpp
index ccd566b1409e9..016c48633d59b 100644
--- a/lib/Localization/LocalizationFormat.cpp
+++ b/lib/Localization/LocalizationFormat.cpp
@@ -64,11 +64,11 @@ bool SerializedLocalizationWriter::emit(llvm::StringRef filePath) {
 
   offset_type offset;
   {
-    llvm::support::endian::write<offset_type>(OS, 0, llvm::support::little);
+    llvm::support::endian::write<offset_type>(OS, 0, llvm::endianness::little);
     offset = generator.Emit(OS);
   }
   OS.seek(0);
-  llvm::support::endian::write(OS, offset, llvm::support::little);
+  llvm::support::endian::write(OS, offset, llvm::endianness::little);
   OS.close();
 
   return OS.has_error();
@@ -116,7 +116,8 @@ SerializedLocalizationProducer::SerializedLocalizationProducer(
 bool SerializedLocalizationProducer::initializeImpl() {
   auto base =
       reinterpret_cast<const unsigned char *>(Buffer.get()->getBufferStart());
-  auto tableOffset = endian::read<offset_type>(base, little);
+  auto tableOffset =
+      llvm::support::endian::read<offset_type>(base, llvm::endianness::little);
   SerializedTable.reset(SerializedLocalizationTable::Create(
       base + tableOffset, base + sizeof(offset_type), base));
   return true;
diff --git a/lib/Option/Options.cpp b/lib/Option/Options.cpp
index aeeed8dc9797d..6a159de3150ba 100644
--- a/lib/Option/Options.cpp
+++ b/lib/Option/Options.cpp
@@ -27,10 +27,7 @@ using namespace llvm::opt;
 #undef PREFIX
 
 static const llvm::opt::GenericOptTable::Info InfoTable[] = {
-#define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
-               HELPTEXT, METAVAR, VALUES)                                      \
-  {PREFIX, NAME,  HELPTEXT,    METAVAR,     OPT_##ID,  Option::KIND##Class,    \
-   PARAM,  FLAGS, OPT_##GROUP, OPT_##ALIAS, ALIASARGS, VALUES},
+#define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
 #include "swift/Option/Options.inc"
 #undef OPTION
 };
diff --git a/lib/Serialization/Deserialization.cpp b/lib/Serialization/Deserialization.cpp
index 1bdf847588bbc..93caaa85ae324 100644
--- a/lib/Serialization/Deserialization.cpp
+++ b/lib/Serialization/Deserialization.cpp
@@ -8007,6 +8007,18 @@ class SwiftToClangBasicReader :
 
     return attr;
   }
+
+  // CountAttributedType is a clang type representing a pointer with
+  // a "counted_by" type attribute and DynamicRangePointerType is
+  // representing a "__ended_by" type attribute.
+  // TypeCoupledDeclRefInfo is used to hold information of a declaration
+  // referenced from an expression argument of "__counted_by(expr)" or
+  // "__ended_by(expr)".
+  // Nothing to be done for now as we currently don't import
+  // these types into Swift.
+  clang::TypeCoupledDeclRefInfo readTypeCoupledDeclRefInfo() {
+    llvm_unreachable("TypeCoupledDeclRefInfo shouldn't be reached from swift");
+  }
 };
 
 } // end anonymous namespace
diff --git a/lib/Serialization/DeserializeSIL.cpp b/lib/Serialization/DeserializeSIL.cpp
index 135640d62b139..3504ef71939d3 100644
--- a/lib/Serialization/DeserializeSIL.cpp
+++ b/lib/Serialization/DeserializeSIL.cpp
@@ -13,12 +13,12 @@
 #define DEBUG_TYPE "deserialize"
 
 #include "DeserializeSIL.h"
-
 #include "BCReadingExtras.h"
 #include "DeserializationErrors.h"
 #include "ModuleFile.h"
 #include "SILFormat.h"
 #include "SILSerializationFunctionBuilder.h"
+#include "SerializationFormat.h"
 
 #include "swift/AST/DiagnosticsSIL.h"
 #include "swift/AST/GenericSignature.h"
@@ -143,14 +143,14 @@ class SILDeserializer::FuncTableInfo {
 
   internal_key_type ReadKey(const uint8_t *data, unsigned length) {
     assert(length == sizeof(uint32_t) && "Expect a single IdentifierID.");
-    IdentifierID keyID = endian::readNext<uint32_t, little, unaligned>(data);
+    IdentifierID keyID = readNext<uint32_t>(data);
     return MF.getIdentifierText(keyID);
   }
 
   static data_type ReadData(internal_key_type key, const uint8_t *data,
                             unsigned length) {
     assert(length == sizeof(uint32_t) && "Expect a single DeclID.");
-    data_type result = endian::readNext<uint32_t, little, unaligned>(data);
+    data_type result = readNext<uint32_t>(data);
     return result;
   }
 };
diff --git a/lib/Serialization/ModuleFile.cpp b/lib/Serialization/ModuleFile.cpp
index 0542ce66aefef..637164e0e49bc 100644
--- a/lib/Serialization/ModuleFile.cpp
+++ b/lib/Serialization/ModuleFile.cpp
@@ -11,15 +11,14 @@
 //===----------------------------------------------------------------------===//
 
 #include "ModuleFile.h"
-#include "ModuleFileCoreTableInfo.h"
 #include "BCReadingExtras.h"
 #include "DeserializationErrors.h"
+#include "ModuleFileCoreTableInfo.h"
 #include "ModuleFormat.h"
-#include "swift/Serialization/SerializationOptions.h"
-#include "swift/Subsystems.h"
-#include "swift/AST/DiagnosticsSema.h"
+#include "SerializationFormat.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTMangler.h"
+#include "swift/AST/DiagnosticsSema.h"
 #include "swift/AST/GenericSignature.h"
 #include "swift/AST/ModuleLoader.h"
 #include "swift/AST/NameLookup.h"
@@ -27,7 +26,9 @@
 #include "swift/AST/USRGeneration.h"
 #include "swift/Basic/Range.h"
 #include "swift/ClangImporter/ClangImporter.h"
+#include "swift/Serialization/SerializationOptions.h"
 #include "swift/Serialization/SerializedModuleLoader.h"
+#include "swift/Subsystems.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/Chrono.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -1120,7 +1121,7 @@ void ModuleFile::collectBasicSourceFileInfo(
   auto *End = Core->SourceFileListData.bytes_end();
   while (Cursor < End) {
     // FilePath (byte offset in 'SourceLocsTextData').
-    auto fileID = endian::readNext<uint32_t, little, unaligned>(Cursor);
+    auto fileID = readNext<uint32_t>(Cursor);
 
     // InterfaceHashIncludingTypeMembers (fixed length string).
     auto fpStrIncludingTypeMembers = StringRef{reinterpret_cast<const char *>(Cursor),
@@ -1133,9 +1134,9 @@ void ModuleFile::collectBasicSourceFileInfo(
     Cursor += Fingerprint::DIGEST_LENGTH;
 
     // LastModified (nanoseconds since epoch).
-    auto timestamp = endian::readNext<uint64_t, little, unaligned>(Cursor);
+    auto timestamp = readNext<uint64_t>(Cursor);
     // FileSize (num of bytes).
-    auto fileSize = endian::readNext<uint64_t, little, unaligned>(Cursor);
+    auto fileSize = readNext<uint64_t>(Cursor);
 
     assert(fileID < Core->SourceLocsTextData.size());
     auto filePath = Core->SourceLocsTextData.substr(fileID);
@@ -1165,8 +1166,7 @@ void ModuleFile::collectBasicSourceFileInfo(
 }
 
 static StringRef readLocString(const char *&Data, StringRef StringData) {
-  auto Str =
-      StringData.substr(endian::readNext<uint32_t, little, unaligned>(Data));
+  auto Str = StringData.substr(readNext<uint32_t>(Data));
   size_t TerminatorOffset = Str.find('\0');
   assert(TerminatorOffset != StringRef::npos && "unterminated string data");
   return Str.slice(0, TerminatorOffset);
@@ -1174,13 +1174,13 @@ static StringRef readLocString(const char *&Data, StringRef StringData) {
 
 static void readRawLoc(ExternalSourceLocs::RawLoc &Loc, const char *&Data,
                        StringRef StringData) {
-  Loc.Offset = endian::readNext<uint32_t, little, unaligned>(Data);
-  Loc.Line = endian::readNext<uint32_t, little, unaligned>(Data);
-  Loc.Column = endian::readNext<uint32_t, little, unaligned>(Data);
+  Loc.Offset = readNext<uint32_t>(Data);
+  Loc.Line = readNext<uint32_t>(Data);
+  Loc.Column = readNext<uint32_t>(Data);
 
-  Loc.Directive.Offset = endian::readNext<uint32_t, little, unaligned>(Data);
-  Loc.Directive.LineOffset = endian::readNext<int32_t, little, unaligned>(Data);
-  Loc.Directive.Length = endian::readNext<uint32_t, little, unaligned>(Data);
+  Loc.Directive.Offset = readNext<uint32_t>(Data);
+  Loc.Directive.LineOffset = readNext<int32_t>(Data);
+  Loc.Directive.Length = readNext<uint32_t>(Data);
   Loc.Directive.Name = readLocString(Data, StringData);
 }
 
@@ -1225,19 +1225,18 @@ ModuleFile::getExternalRawLocsForDecl(const Decl *D) const {
   ExternalSourceLocs::RawLocs Result;
   Result.SourceFilePath = readLocString(Record, Core->SourceLocsTextData);
 
-  const auto DocRangesOffset =
-      endian::readNext<uint32_t, little, unaligned>(Record);
+  const auto DocRangesOffset = readNext<uint32_t>(Record);
   if (DocRangesOffset) {
     assert(!Core->DocRangesData.empty());
     const auto *Data = Core->DocRangesData.data() + DocRangesOffset;
-    const auto NumLocs = endian::readNext<uint32_t, little, unaligned>(Data);
+    const auto NumLocs = readNext<uint32_t>(Data);
     assert(NumLocs);
 
     for (uint32_t I = 0; I < NumLocs; ++I) {
       auto &Range =
           Result.DocRanges.emplace_back(ExternalSourceLocs::RawLoc(), 0);
       readRawLoc(Range.first, Data, Core->SourceLocsTextData);
-      Range.second = endian::readNext<uint32_t, little, unaligned>(Data);
+      Range.second = readNext<uint32_t>(Data);
     }
   }
 
diff --git a/lib/Serialization/ModuleFileCoreTableInfo.h b/lib/Serialization/ModuleFileCoreTableInfo.h
index 659cfd0344b1a..a48672d2666d3 100644
--- a/lib/Serialization/ModuleFileCoreTableInfo.h
+++ b/lib/Serialization/ModuleFileCoreTableInfo.h
@@ -13,8 +13,9 @@
 #ifndef SWIFT_SERIALIZATION_MODULEFILECORETABLEINFO_H
 #define SWIFT_SERIALIZATION_MODULEFILECORETABLEINFO_H
 
-#include "ModuleFileSharedCore.h"
 #include "DocFormat.h"
+#include "ModuleFileSharedCore.h"
+#include "SerializationFormat.h"
 #include "SourceInfoFormat.h"
 #include "swift/AST/RawComment.h"
 #include "llvm/Support/DJB.h"
@@ -51,16 +52,14 @@ class ModuleFileSharedCore::DeclTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
-    unsigned keyLength = endian::readNext<uint16_t, little, unaligned>(data);
-    unsigned dataLength = endian::readNext<uint16_t, little, unaligned>(data);
+    unsigned keyLength = readNext<uint16_t>(data);
+    unsigned dataLength = readNext<uint16_t>(data);
     return { keyLength, dataLength };
   }
 
   static internal_key_type ReadKey(const uint8_t *data, unsigned length) {
     using namespace swift::serialization;
-    using namespace llvm::support;
-    uint8_t kind = endian::readNext<uint8_t, little, unaligned>(data);
+    uint8_t kind = readNext<uint8_t>(data);
     switch (kind) {
     case static_cast<uint8_t>(DeclNameKind::Normal): {
       StringRef str(reinterpret_cast<const char *>(data),
@@ -78,11 +77,10 @@ class ModuleFileSharedCore::DeclTableInfo {
 
   static data_type ReadData(internal_key_type key, const uint8_t *data,
                             unsigned length) {
-    using namespace llvm::support;
     data_type result;
     while (length > 0) {
       uint8_t kind = *data++;
-      DeclID offset = endian::readNext<uint32_t, little, unaligned>(data);
+      DeclID offset = readNext<uint32_t>(data);
       result.push_back({ kind, offset });
       length -= 5;
     }
@@ -114,9 +112,8 @@ class ModuleFileSharedCore::ExtensionTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
-    unsigned keyLength = endian::readNext<uint16_t, little, unaligned>(data);
-    unsigned dataLength = endian::readNext<uint16_t, little, unaligned>(data);
+    unsigned keyLength = readNext<uint16_t>(data);
+    unsigned dataLength = readNext<uint16_t>(data);
     return { keyLength, dataLength };
   }
 
@@ -126,14 +123,12 @@ class ModuleFileSharedCore::ExtensionTableInfo {
 
   data_type ReadData(internal_key_type key, const uint8_t *data,
                      unsigned length) {
-    using namespace llvm::support;
     data_type result;
     const uint8_t *limit = data + length;
     while (data < limit) {
-      DeclID offset = endian::readNext<uint32_t, little, unaligned>(data);
+      DeclID offset = readNext<uint32_t>(data);
 
-      int32_t nameIDOrLength =
-          endian::readNext<int32_t, little, unaligned>(data);
+      int32_t nameIDOrLength = readNext<int32_t>(data);
       StringRef moduleNameOrMangledBase;
       if (nameIDOrLength < 0) {
         StringRef moduleName = Core.getModuleNameFromID(-nameIDOrLength);
@@ -180,8 +175,7 @@ class ModuleFileSharedCore::LocalDeclTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
-    unsigned keyLength = endian::readNext<uint16_t, little, unaligned>(data);
+    unsigned keyLength = readNext<uint16_t>(data);
     return { keyLength, sizeof(uint32_t) };
   }
 
@@ -191,8 +185,7 @@ class ModuleFileSharedCore::LocalDeclTableInfo {
 
   static data_type ReadData(internal_key_type key, const uint8_t *data,
                             unsigned length) {
-    using namespace llvm::support;
-    return endian::readNext<uint32_t, little, unaligned>(data);
+    return readNext<uint32_t>(data);
   }
 };
 
@@ -217,9 +210,8 @@ class ModuleFileSharedCore::NestedTypeDeclsTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
-    unsigned keyLength = endian::readNext<uint16_t, little, unaligned>(data);
-    unsigned dataLength = endian::readNext<uint16_t, little, unaligned>(data);
+    unsigned keyLength = readNext<uint16_t>(data);
+    unsigned dataLength = readNext<uint16_t>(data);
     return { keyLength, dataLength };
   }
 
@@ -229,11 +221,10 @@ class ModuleFileSharedCore::NestedTypeDeclsTableInfo {
 
   static data_type ReadData(internal_key_type key, const uint8_t *data,
                             unsigned length) {
-    using namespace llvm::support;
     data_type result;
     while (length > 0) {
-      DeclID parentID = endian::readNext<uint32_t, little, unaligned>(data);
-      DeclID childID = endian::readNext<uint32_t, little, unaligned>(data);
+      DeclID parentID = readNext<uint32_t>(data);
+      DeclID childID = readNext<uint32_t>(data);
       result.push_back({ parentID, childID });
       length -= sizeof(uint32_t) * 2;
     }
@@ -277,15 +268,13 @@ class ModuleFileSharedCore::DeclMemberNamesTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
-    unsigned keyLength = endian::readNext<uint16_t, little, unaligned>(data);
+    unsigned keyLength = readNext<uint16_t>(data);
     return { keyLength, sizeof(uint32_t) };
   }
 
   static internal_key_type ReadKey(const uint8_t *data, unsigned length) {
     using namespace swift::serialization;
-    using namespace llvm::support;
-    uint8_t kind = endian::readNext<uint8_t, little, unaligned>(data);
+    uint8_t kind = readNext<uint8_t>(data);
     switch (kind) {
     case static_cast<uint8_t>(DeclNameKind::Normal): {
       StringRef str(reinterpret_cast<const char *>(data),
@@ -305,9 +294,8 @@ class ModuleFileSharedCore::DeclMemberNamesTableInfo {
 
   static data_type ReadData(internal_key_type key, const uint8_t *data,
                             unsigned length) {
-    using namespace llvm::support;
     assert(length == sizeof(uint32_t));
-    return endian::readNext<uint32_t, little, unaligned>(data);
+    return readNext<uint32_t>(data);
   }
 };
 
@@ -338,22 +326,19 @@ class ModuleFileSharedCore::DeclMembersTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
-    unsigned dataLength = endian::readNext<uint16_t, little, unaligned>(data);
+    unsigned dataLength = readNext<uint16_t>(data);
     return { sizeof(uint32_t), dataLength };
   }
 
   static internal_key_type ReadKey(const uint8_t *data, unsigned length) {
-    using namespace llvm::support;
-    return endian::readNext<uint32_t, little, unaligned>(data);
+    return readNext<uint32_t>(data);
   }
 
   static data_type ReadData(internal_key_type key, const uint8_t *data,
                             unsigned length) {
-    using namespace llvm::support;
     data_type result;
     while (length > 0) {
-      DeclID declID = endian::readNext<uint32_t, little, unaligned>(data);
+      DeclID declID = readNext<uint32_t>(data);
       result.push_back(declID);
       length -= sizeof(uint32_t);
     }
@@ -384,9 +369,8 @@ class ModuleFileSharedCore::ObjCMethodTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
-    unsigned keyLength = endian::readNext<uint16_t, little, unaligned>(data);
-    unsigned dataLength = endian::readNext<uint32_t, little, unaligned>(data);
+    unsigned keyLength = readNext<uint16_t>(data);
+    unsigned dataLength = readNext<uint32_t>(data);
     return { keyLength, dataLength };
   }
 
@@ -396,13 +380,12 @@ class ModuleFileSharedCore::ObjCMethodTableInfo {
 
   static data_type ReadData(internal_key_type key, const uint8_t *data,
                             unsigned length) {
-    using namespace llvm::support;
     const constexpr auto recordSize = sizeof(uint32_t) + 1 + sizeof(uint32_t);
     data_type result;
     while (length > 0) {
-      unsigned ownerLen = endian::readNext<uint32_t, little, unaligned>(data);
+      unsigned ownerLen = readNext<uint32_t>(data);
       bool isInstanceMethod = *data++ != 0;
-      DeclID methodID = endian::readNext<uint32_t, little, unaligned>(data);
+      DeclID methodID = readNext<uint32_t>(data);
       std::string ownerName((const char *)data, ownerLen);
       result.push_back(
         std::make_tuple(std::move(ownerName), isInstanceMethod, methodID));
@@ -438,9 +421,8 @@ class ModuleFileSharedCore::DerivativeFunctionConfigTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
-    unsigned keyLength = endian::readNext<uint16_t, little, unaligned>(data);
-    unsigned dataLength = endian::readNext<uint16_t, little, unaligned>(data);
+    unsigned keyLength = readNext<uint16_t>(data);
+    unsigned dataLength = readNext<uint16_t>(data);
     return {keyLength, dataLength};
   }
 
@@ -450,12 +432,11 @@ class ModuleFileSharedCore::DerivativeFunctionConfigTableInfo {
 
   static data_type ReadData(internal_key_type key, const uint8_t *data,
                             unsigned length) {
-    using namespace llvm::support;
     data_type result;
     const uint8_t *limit = data + length;
     while (data < limit) {
-      DeclID genSigId = endian::readNext<uint32_t, little, unaligned>(data);
-      int32_t nameLength = endian::readNext<int32_t, little, unaligned>(data);
+      DeclID genSigId = readNext<uint32_t>(data);
+      int32_t nameLength = readNext<int32_t>(data);
       std::string mangledName(reinterpret_cast<const char *>(data), nameLength);
       data += nameLength;
       result.push_back({std::string(mangledName), genSigId});
@@ -491,9 +472,8 @@ class ModuleFileSharedCore::DeclCommentTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
-    unsigned keyLength = endian::readNext<uint32_t, little, unaligned>(data);
-    unsigned dataLength = endian::readNext<uint32_t, little, unaligned>(data);
+    unsigned keyLength = readNext<uint32_t>(data);
+    unsigned dataLength = readNext<uint32_t>(data);
     return { keyLength, dataLength };
   }
 
@@ -503,29 +483,27 @@ class ModuleFileSharedCore::DeclCommentTableInfo {
 
   data_type ReadData(internal_key_type key, const uint8_t *data,
                      unsigned length) {
-    using namespace llvm::support;
     data_type result = std::make_unique<DeserializedCommentInfo>();
 
     {
-      unsigned BriefSize = endian::readNext<uint32_t, little, unaligned>(data);
+      unsigned BriefSize = readNext<uint32_t>(data);
       result->Info.Brief = StringRef(reinterpret_cast<const char *>(data), BriefSize);
       data += BriefSize;
     }
 
-    unsigned NumComments = endian::readNext<uint32_t, little, unaligned>(data);
+    unsigned NumComments = readNext<uint32_t>(data);
 
     for (unsigned i = 0; i != NumComments; ++i) {
-      unsigned StartColumn =
-          endian::readNext<uint32_t, little, unaligned>(data);
-      unsigned RawSize = endian::readNext<uint32_t, little, unaligned>(data);
+      unsigned StartColumn = readNext<uint32_t>(data);
+      unsigned RawSize = readNext<uint32_t>(data);
       auto RawText = StringRef(reinterpret_cast<const char *>(data), RawSize);
       data += RawSize;
 
       result->RawCommentStore.emplace_back(RawText, StartColumn);
     }
     result->Info.Raw = RawComment(result->RawCommentStore);
-    result->Info.Group = endian::readNext<uint32_t, little, unaligned>(data);
-    result->Info.SourceOrder = endian::readNext<uint32_t, little, unaligned>(data);
+    result->Info.Group = readNext<uint32_t>(data);
+    result->Info.SourceOrder = readNext<uint32_t>(data);
     return result;
   }
 };
@@ -550,8 +528,7 @@ class ModuleFileSharedCore::DeclUSRTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
-    unsigned keyLength = endian::readNext<uint32_t, little, unaligned>(data);
+    unsigned keyLength = readNext<uint32_t>(data);
     unsigned dataLength = 4;
     return { keyLength, dataLength };
   }
@@ -560,10 +537,10 @@ class ModuleFileSharedCore::DeclUSRTableInfo {
     return StringRef(reinterpret_cast<const char*>(data), length);
   }
 
-  data_type ReadData(internal_key_type key, const uint8_t *data, unsigned length) {
-    using namespace llvm::support;
+  data_type ReadData(internal_key_type key, const uint8_t *data,
+                     unsigned length) {
     assert(length == 4);
-    return endian::readNext<uint32_t, little, unaligned>(data);
+    return readNext<uint32_t>(data);
   }
 };
 
@@ -588,19 +565,16 @@ class ModuleFileSharedCore::DeclFingerprintsTableInfo {
   }
 
   static std::pair<unsigned, unsigned> ReadKeyDataLength(const uint8_t *&data) {
-    using namespace llvm::support;
     const unsigned dataLen = Fingerprint::DIGEST_LENGTH;
     return {sizeof(uint32_t), dataLen};
   }
 
   static internal_key_type ReadKey(const uint8_t *data, unsigned length) {
-    using namespace llvm::support;
-    return endian::readNext<uint32_t, little, unaligned>(data);
+    return readNext<uint32_t>(data);
   }
 
   static data_type ReadData(internal_key_type key, const uint8_t *data,
                             unsigned length) {
-    using namespace llvm::support;
     auto str = llvm::StringRef{reinterpret_cast<const char *>(data),
                                Fingerprint::DIGEST_LENGTH};
     if (auto fp = Fingerprint::fromString(str))
diff --git a/lib/Serialization/ModuleFileSharedCore.cpp b/lib/Serialization/ModuleFileSharedCore.cpp
index c389311df45d8..c593a751b55c2 100644
--- a/lib/Serialization/ModuleFileSharedCore.cpp
+++ b/lib/Serialization/ModuleFileSharedCore.cpp
@@ -14,6 +14,7 @@
 #include "BCReadingExtras.h"
 #include "DeserializationErrors.h"
 #include "ModuleFileCoreTableInfo.h"
+#include "SerializationFormat.h"
 #include "swift/Basic/LangOptions.h"
 #include "swift/Parse/ParseVersion.h"
 #include "swift/Serialization/SerializedModuleLoader.h"
@@ -1014,9 +1015,9 @@ ModuleFileSharedCore::readGroupTable(ArrayRef<uint64_t> Fields,
                                      StringRef BlobData) const {
   auto pMap = std::make_unique<llvm::DenseMap<unsigned, StringRef>>();
   auto Data = reinterpret_cast<const uint8_t *>(BlobData.data());
-  unsigned GroupCount = endian::readNext<uint32_t, little, unaligned>(Data);
+  unsigned GroupCount = readNext<uint32_t>(Data);
   for (unsigned I = 0; I < GroupCount; ++I) {
-    auto RawSize = endian::readNext<uint32_t, little, unaligned>(Data);
+    auto RawSize = readNext<uint32_t>(Data);
     auto RawText = StringRef(reinterpret_cast<const char *>(Data), RawSize);
     Data += RawSize;
     (*pMap)[I] = RawText;
diff --git a/lib/Serialization/Serialization.cpp b/lib/Serialization/Serialization.cpp
index 51e4c1f74e2ad..6e4637680f4df 100644
--- a/lib/Serialization/Serialization.cpp
+++ b/lib/Serialization/Serialization.cpp
@@ -146,14 +146,14 @@ namespace {
       uint32_t dataLength = (sizeof(uint32_t) + 1) * data.size();
       assert(dataLength == static_cast<uint16_t>(dataLength));
 
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint16_t>(keyLength);
       writer.write<uint16_t>(dataLength);
       return { keyLength, dataLength };
     }
 
     void EmitKey(raw_ostream &out, key_type_ref key, unsigned len) {
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       switch (key.getKind()) {
       case DeclBaseName::Kind::Normal:
         writer.write<uint8_t>(static_cast<uint8_t>(DeclNameKind::Normal));
@@ -174,7 +174,7 @@ namespace {
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
       static_assert(declIDFitsIn32Bits(), "DeclID too large");
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       for (auto entry : data) {
         writer.write<uint8_t>(entry.first);
         writer.write<uint32_t>(entry.second);
@@ -230,7 +230,7 @@ namespace {
           dataLength += nameData;
       }
       assert(dataLength == static_cast<uint16_t>(dataLength));
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint16_t>(keyLength);
       writer.write<uint16_t>(dataLength);
       return { keyLength, dataLength };
@@ -243,7 +243,7 @@ namespace {
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
       static_assert(declIDFitsIn32Bits(), "DeclID too large");
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       for (auto entry : data) {
         StringRef dataToWrite;
         writer.write<uint32_t>(entry.second);
@@ -273,7 +273,7 @@ namespace {
       uint32_t keyLength = key.size();
       assert(keyLength == static_cast<uint16_t>(keyLength));
       uint32_t dataLength = sizeof(uint32_t);
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint16_t>(keyLength);
       // No need to write the data length; it's constant.
       return { keyLength, dataLength };
@@ -286,7 +286,7 @@ namespace {
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
       static_assert(declIDFitsIn32Bits(), "DeclID too large");
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint32_t>(data);
     }
   };
@@ -315,7 +315,7 @@ namespace {
       assert(keyLength == static_cast<uint16_t>(keyLength));
       uint32_t dataLength = (sizeof(uint32_t) * 2) * data.size();
       assert(dataLength == static_cast<uint16_t>(dataLength));
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint16_t>(keyLength);
       writer.write<uint16_t>(dataLength);
       return { keyLength, dataLength };
@@ -329,7 +329,7 @@ namespace {
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
       static_assert(declIDFitsIn32Bits(), "DeclID too large");
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       for (auto entry : data) {
         writer.write<uint32_t>(entry.first);
         writer.write<uint32_t>(entry.second);
@@ -370,14 +370,14 @@ namespace {
       }
       assert(keyLength == static_cast<uint16_t>(keyLength));
       uint32_t dataLength = sizeof(uint32_t);
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint16_t>(keyLength);
       // No need to write dataLength, it's constant.
       return { keyLength, dataLength };
     }
 
     void EmitKey(raw_ostream &out, key_type_ref key, unsigned len) {
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       switch (key.getKind()) {
       case DeclBaseName::Kind::Normal:
         writer.write<uint8_t>(static_cast<uint8_t>(DeclNameKind::Normal));
@@ -398,7 +398,7 @@ namespace {
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
       static_assert(bitOffsetFitsIn32Bits(), "BitOffset too large");
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint32_t>(static_cast<uint32_t>(data));
     }
   };
@@ -423,7 +423,7 @@ namespace {
       // with the same DeclBaseName. Seems highly unlikely.
       assert((data.size() < (1 << 14)) && "Too many members");
       uint32_t dataLength = sizeof(uint32_t) * data.size(); // value DeclIDs
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       // No need to write the key length; it's constant.
       writer.write<uint16_t>(dataLength);
       return { sizeof(uint32_t), dataLength };
@@ -432,14 +432,14 @@ namespace {
     void EmitKey(raw_ostream &out, key_type_ref key, unsigned len) {
       static_assert(declIDFitsIn32Bits(), "DeclID too large");
       assert(len == sizeof(uint32_t));
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint32_t>(key);
     }
 
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
       static_assert(declIDFitsIn32Bits(), "DeclID too large");
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       for (auto entry : data) {
         writer.write<uint32_t>(entry);
       }
@@ -463,7 +463,7 @@ namespace {
 
     std::pair<unsigned, unsigned>
     EmitKeyDataLength(raw_ostream &out, key_type_ref key, data_type_ref data) {
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       // No need to write the key or value length; they're both constant.
       const unsigned valueLen = Fingerprint::DIGEST_LENGTH;
       return {sizeof(uint32_t), valueLen};
@@ -472,7 +472,7 @@ namespace {
     void EmitKey(raw_ostream &out, key_type_ref key, unsigned len) {
       static_assert(declIDFitsIn32Bits(), "DeclID too large");
       assert(len == sizeof(uint32_t));
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint32_t>(key);
     }
 
@@ -480,7 +480,7 @@ namespace {
                   unsigned len) {
       static_assert(declIDFitsIn32Bits(), "DeclID too large");
       assert(len == Fingerprint::DIGEST_LENGTH);
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       out << data;
     }
   };
@@ -5974,6 +5974,18 @@ class ClangToSwiftBasicWriter :
     writeBool(swiftAttr->isPackExpansion());
     writeUInt64(S.addUniquedStringRef(swiftAttr->getAttribute()));
   }
+
+  // CountAttributedType is a clang type representing a pointer with
+  // a "counted_by" type attribute and DynamicRangePointerType is
+  // representing a "__ended_by" type attribute.
+  // TypeCoupledDeclRefInfo is used to hold information of a declaration
+  // referenced from an expression argument of "__counted_by(expr)" or
+  // "__ended_by(expr)".
+  // Nothing to be done for now as we currently don't import
+  // these types into Swift.
+  void writeTypeCoupledDeclRefInfo(clang::TypeCoupledDeclRefInfo info) {
+    llvm_unreachable("TypeCoupledDeclRefInfo shouldn't be reached from swift");
+  }
 };
 
 }
@@ -6211,7 +6223,7 @@ static void writeDeclTable(const index_block::DeclListLayout &DeclList,
 
     llvm::raw_svector_ostream blobStream(hashTableBlob);
     // Make sure that no bucket is at offset 0
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = generator.Emit(blobStream);
   }
 
@@ -6237,7 +6249,7 @@ writeExtensionTable(const index_block::ExtensionTableLayout &ExtensionTable,
 
     llvm::raw_svector_ostream blobStream(hashTableBlob);
     // Make sure that no bucket is at offset 0
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = generator.Emit(blobStream, info);
   }
 
@@ -6253,7 +6265,7 @@ static void writeLocalDeclTable(const index_block::DeclListLayout &DeclList,
   {
     llvm::raw_svector_ostream blobStream(hashTableBlob);
     // Make sure that no bucket is at offset 0
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = generator.Emit(blobStream);
   }
 
@@ -6273,7 +6285,7 @@ writeNestedTypeDeclsTable(const index_block::NestedTypeDeclsLayout &declList,
 
     llvm::raw_svector_ostream blobStream(hashTableBlob);
     // Make sure that no bucket is at offset 0
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = generator.Emit(blobStream);
   }
 
@@ -6298,7 +6310,7 @@ writeDeclMemberNamesTable(const index_block::DeclMemberNamesLayout &declNames,
 
     llvm::raw_svector_ostream blobStream(hashTableBlob);
     // Make sure that no bucket is at offset 0
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = generator.Emit(blobStream);
   }
 
@@ -6318,7 +6330,7 @@ writeDeclMembersTable(const decl_member_tables_block::DeclMembersLayout &mems,
 
     llvm::raw_svector_ostream blobStream(hashTableBlob);
     // Make sure that no bucket is at offset 0
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = generator.Emit(blobStream);
   }
 
@@ -6339,7 +6351,7 @@ writeDeclFingerprintsTable(const index_block::DeclFingerprintsLayout &fpl,
 
     llvm::raw_svector_ostream blobStream(hashTableBlob);
     // Make sure that no bucket is at offset 0
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = generator.Emit(blobStream);
   }
 
@@ -6375,7 +6387,7 @@ namespace {
         dataLength += std::get<0>(entry).size();
       }
 
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint16_t>(keyLength);
       writer.write<uint32_t>(dataLength);
       return { keyLength, dataLength };
@@ -6392,7 +6404,7 @@ namespace {
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
       static_assert(declIDFitsIn32Bits(), "DeclID too large");
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       for (const auto &entry : data) {
         writer.write<uint32_t>(std::get<0>(entry).size());
         writer.write<uint8_t>(std::get<1>(entry));
@@ -6425,7 +6437,7 @@ static void writeObjCMethodTable(const index_block::ObjCMethodTableLayout &out,
     }
 
     // Make sure that no bucket is at offset 0
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = generator.Emit(blobStream);
   }
 
@@ -6458,7 +6470,7 @@ namespace {
       for (auto entry : data)
         dataLength += entry.first.size();
       assert(dataLength == static_cast<uint16_t>(dataLength));
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       writer.write<uint16_t>(keyLength);
       writer.write<uint16_t>(dataLength);
       return { keyLength, dataLength };
@@ -6471,7 +6483,7 @@ namespace {
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
       static_assert(declIDFitsIn32Bits(), "DeclID too large");
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       for (auto &entry : data) {
         // Write `GenericSignatureID`.
         writer.write<uint32_t>(entry.second);
@@ -6496,7 +6508,7 @@ static void writeDerivativeFunctionConfigs(
     for (auto &entry : derivativeConfigs)
       generator.insert(entry.first.get(), entry.second);
     // Make sure that no bucket is at offset 0.
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = generator.Emit(blobStream);
   }
   SmallVector<uint64_t, 8> scratch;
diff --git a/lib/Serialization/SerializationFormat.h b/lib/Serialization/SerializationFormat.h
new file mode 100644
index 0000000000000..867b5baa62215
--- /dev/null
+++ b/lib/Serialization/SerializationFormat.h
@@ -0,0 +1,33 @@
+//===--- SerializationFormat.h - Serialization helpers ------ ---*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Various helper functions to deal with common serialization functionality.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SERIALIZATION_SERIALIZATIONFORMAT_H
+#define SWIFT_SERIALIZATION_SERIALIZATIONFORMAT_H
+
+#include "llvm/ADT/bit.h"
+#include "llvm/Support/Endian.h"
+
+namespace swift {
+
+template <typename value_type, typename CharT>
+[[nodiscard]] inline value_type readNext(const CharT *&memory) {
+  return llvm::support::endian::readNext<value_type, llvm::endianness::little, llvm::support::unaligned>(memory);
+}
+
+} // end namespace swift
+
+#endif
diff --git a/lib/Serialization/SerializeDoc.cpp b/lib/Serialization/SerializeDoc.cpp
index 812bf48f1ddb9..a2b24af1ada69 100644
--- a/lib/Serialization/SerializeDoc.cpp
+++ b/lib/Serialization/SerializeDoc.cpp
@@ -232,7 +232,7 @@ class DeclCommentTableInfo {
 
     // Source order.
     dataLength += numLen;
-    endian::Writer writer(out, little);
+    endian::Writer writer(out, llvm::endianness::little);
     writer.write<uint32_t>(keyLength);
     writer.write<uint32_t>(dataLength);
     return { keyLength, dataLength };
@@ -244,7 +244,7 @@ class DeclCommentTableInfo {
 
   void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                 unsigned len) {
-    endian::Writer writer(out, little);
+    endian::Writer writer(out, llvm::endianness::little);
     writer.write<uint32_t>(data.Brief.size());
     out << data.Brief;
     writer.write<uint32_t>(data.Raw.Comments.size());
@@ -300,7 +300,7 @@ static void writeGroupNames(const comment_block::GroupNamesLayout &GroupNames,
                             ArrayRef<StringRef> Names) {
   llvm::SmallString<32> Blob;
   llvm::raw_svector_ostream BlobStream(Blob);
-  endian::Writer Writer(BlobStream, little);
+  endian::Writer Writer(BlobStream, llvm::endianness::little);
   Writer.write<uint32_t>(Names.size());
   for (auto N : Names) {
     Writer.write<uint32_t>(N.size());
@@ -447,7 +447,7 @@ static void writeDeclCommentTable(
   {
     llvm::raw_svector_ostream blobStream(hashTableBlob);
     // Make sure that no bucket is at offset 0
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = Writer.generator.Emit(blobStream);
   }
 
@@ -519,7 +519,7 @@ class USRTableInfo {
     const unsigned numLen = 4;
     uint32_t keyLength = key.size();
     uint32_t dataLength = numLen;
-    endian::Writer writer(out, little);
+    endian::Writer writer(out, llvm::endianness::little);
     writer.write<uint32_t>(keyLength);
     return { keyLength, dataLength };
   }
@@ -530,7 +530,7 @@ class USRTableInfo {
 
   void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                 unsigned len) {
-    endian::Writer writer(out, little);
+    endian::Writer writer(out, llvm::endianness::little);
     writer.write<uint32_t>(data);
   }
 };
@@ -560,7 +560,7 @@ class DeclUSRsTableWriter {
     {
       llvm::raw_svector_ostream blobStream(hashTableBlob);
       // Make sure that no bucket is at offset 0
-      endian::write<uint32_t>(blobStream, 0, little);
+      endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
       tableOffset = generator.Emit(blobStream);
     }
     USRsList.emit(scratch, tableOffset, hashTableBlob);
@@ -637,7 +637,7 @@ class DocRangeWriter {
     }
 
     llvm::raw_svector_ostream OS(Buffer);
-    endian::Writer Writer(OS, little);
+    endian::Writer Writer(OS, llvm::endianness::little);
     Writer.write<uint32_t>(DocRanges.size());
     for (const auto &DocRange : DocRanges) {
       writeRawLoc(DocRange.first, Writer, Strings);
@@ -719,7 +719,7 @@ struct BasicDeclLocsTableWriter : public ASTWalker {
     llvm::sys::fs::make_absolute(AbsolutePath);
 
     llvm::raw_svector_ostream Out(Buffer);
-    endian::Writer Writer(Out, little);
+    endian::Writer Writer(Out, llvm::endianness::little);
     Writer.write<uint32_t>(FWriter.getTextOffset(AbsolutePath.str()));
     Writer.write<uint32_t>(
         DocWriter.getDocRangesOffset(D, llvm::ArrayRef(RawLocs->DocRanges)));
@@ -782,7 +782,7 @@ static void emitFileListRecord(llvm::BitstreamWriter &Out,
                            .count();
 
       llvm::raw_svector_ostream out(Buffer);
-      endian::Writer writer(out, little);
+      endian::Writer writer(out, llvm::endianness::little);
       // FilePath.
       writer.write<uint32_t>(fileID);
 
diff --git a/lib/Serialization/SerializeSIL.cpp b/lib/Serialization/SerializeSIL.cpp
index 94eab6a24880f..cc62d734cc6d0 100644
--- a/lib/Serialization/SerializeSIL.cpp
+++ b/lib/Serialization/SerializeSIL.cpp
@@ -147,12 +147,12 @@ namespace {
 
     void EmitKey(raw_ostream &out, key_type_ref key, unsigned len) {
       uint32_t keyID = S.addUniquedStringRef(key);
-      endian::write<uint32_t>(out, keyID, little);
+      endian::write<uint32_t>(out, keyID, llvm::endianness::little);
     }
 
     void EmitData(raw_ostream &out, key_type_ref key, data_type_ref data,
                   unsigned len) {
-      endian::write<uint32_t>(out, data, little);
+      endian::write<uint32_t>(out, data, llvm::endianness::little);
     }
   };
 
@@ -2796,7 +2796,7 @@ static void writeIndexTable(Serializer &S,
 
     llvm::raw_svector_ostream blobStream(hashTableBlob);
     // Make sure that no bucket is at offset 0.
-    endian::write<uint32_t>(blobStream, 0, little);
+    endian::write<uint32_t>(blobStream, 0, llvm::endianness::little);
     tableOffset = generator.Emit(blobStream, tableInfo);
   }
   SmallVector<uint64_t, 8> scratch;
diff --git a/test/AutoDiff/compiler_crashers_fixed/issue-58123-invalid-debug-info.swift b/test/AutoDiff/compiler_crashers_fixed/issue-58123-invalid-debug-info.swift
index da171b9fa71d3..beb746eb5c964 100644
--- a/test/AutoDiff/compiler_crashers_fixed/issue-58123-invalid-debug-info.swift
+++ b/test/AutoDiff/compiler_crashers_fixed/issue-58123-invalid-debug-info.swift
@@ -4,7 +4,7 @@
 // Mutating functions with control flow can cause assertion failure for
 // conflicting debug variable type
 
-// CHECK-LABEL: define internal swiftcc float @"$s4main8TestTypeV24doDifferentiableTimeStep04timeG0ySf_tFTJpSSpSrTA"
+// CHECK-LABEL: define internal swiftcc{{.*}} float @"$s4main8TestTypeV24doDifferentiableTimeStep04timeG0ySf_tFTJpSSpSrTA"
 // CHECK: [[SELF:%.*]] = alloca %T4main8TestTypeV06ManualB7TangentV
 // CHECK: call void @llvm.dbg.value(metadata ptr [[SELF]]
 
diff --git a/test/DebugInfo/debug_scope_distinct.swift b/test/DebugInfo/debug_scope_distinct.swift
index c90756c3e3d6c..1cbc56cca4eb7 100644
--- a/test/DebugInfo/debug_scope_distinct.swift
+++ b/test/DebugInfo/debug_scope_distinct.swift
@@ -1,5 +1,7 @@
 // REQUIRES: differentiable_programming
 
+// XFAIL: *
+
 // RUN: %empty-directory(%t)
 // RUN: %target-swiftc_driver -DM -emit-module -emit-module-path %t/M.swiftmodule %s -module-name M
 // RUN: %target-swiftc_driver -O -g -I %t -c %s -emit-ir -o - | %FileCheck %s
diff --git a/test/Frontend/verify-fixits.swift b/test/Frontend/verify-fixits.swift
index 65ed600df5bb8..bd4399f82d5e3 100644
--- a/test/Frontend/verify-fixits.swift
+++ b/test/Frontend/verify-fixits.swift
@@ -5,10 +5,10 @@
 func labeledFunc(aa: Int, bb: Int) {}
 
 func testNoneMarkerCheck() {
-  // CHECK: [[@LINE+1]]:87: error: A second {{{{}}none}} was found. It may only appear once in an expectation.
+  // CHECK: [[@LINE+1]]:87: error: A second {{\{\{}}none}} was found. It may only appear once in an expectation.
   undefinedFunc() // expected-error {{cannot find 'undefinedFunc' in scope}} {{none}} {{none}}
 
-  // CHECK: [[@LINE+1]]:134: error: {{{{}}none}} must be at the end.
+  // CHECK: [[@LINE+1]]:134: error: {{\{\{}}none}} must be at the end.
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{none}} {{23-26=bb}}
 }
 
@@ -173,27 +173,27 @@ func test1Fixits() {
 
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}}
 
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}}
 
-  // CHECK: [[@LINE+1]]:134: error: expected fix-it not seen; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:134: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{15-18=xx}}
 
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}} {{15-18=aa}}
 
-  // CHECK: [[@LINE+1]]:121: error: expected no fix-its; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected no fix-its; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{none}}
 
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{none}}
 
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}} {{none}}
 
-  // CHECK: [[@LINE+1]]:134: error: expected fix-it not seen; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:134: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=aa}} {{15-18=xx}} {{none}}
 
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{15-18=xx}} {{15-18=aa}} {{none}}
 
   // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
@@ -215,13 +215,13 @@ func test1Fixits() {
   labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{216:15-+1:18=bb}}
               bbx: 1)
 
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{61:15-18=aa}}
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{-1:15-18=aa}}
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{+0:15--1:18=aa}}
-  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{{{}}15-18=aa}}
+  // CHECK: [[@LINE+1]]:121: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}15-18=aa}}
   labeledFunc(aax: 0, bb: 1) // expected-error {{incorrect argument label in call (have 'aax:bb:', expected 'aa:bb:')}} {{61:15-+1:18=aa}}
 }
 
@@ -232,7 +232,7 @@ func testDefaultedLineNumbers() {
   // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
   unlabeledFunc(aa: // expected-error {{extraneous argument label 'aa:' in call}} {{+0:17-+1:5=}}
     1)
-  // CHECK: [[@LINE+1]]:83: error: expected fix-it not seen; actual fix-it seen: {{{{}}17-[[@LINE+2]]:5=}}
+  // CHECK: [[@LINE+1]]:83: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}17-[[@LINE+2]]:5=}}
   unlabeledFunc(aa: // expected-error {{extraneous argument label 'aa:' in call}} {{+0:17-5=}}
     1)
 
@@ -240,7 +240,7 @@ func testDefaultedLineNumbers() {
   // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
   labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{+1:15-+1:18=bb}}
               bbx: 1)
-  // CHECK: [[@LINE+1]]:113: error: expected fix-it not seen; actual fix-it seen: {{{{}}[[@LINE+2]]:15-18=bb}}
+  // CHECK: [[@LINE+1]]:113: error: expected fix-it not seen; actual fix-it seen: {{\{\{}}[[@LINE+2]]:15-18=bb}}
   labeledFunc(aa: 0, // expected-error {{incorrect argument label in call (have 'aa:bbx:', expected 'aa:bb:')}} {{15-+1:18=bb}}
               bbx: 1)
 }
@@ -250,22 +250,22 @@ func test2Fixits() {
 
   labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}}
 
-  // CHECK: [[@LINE+1]]:124: error: expected fix-it not seen; actual fix-its seen: {{{{}}15-18=aa}} {{{{}}23-26=bb}}
+  // CHECK: [[@LINE+1]]:124: error: expected fix-it not seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
   labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=xx}}
 
   labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=bb}}
 
-  // CHECK: [[@LINE+1]]:137: error: expected fix-it not seen; actual fix-its seen: {{{{}}15-18=aa}} {{{{}}23-26=bb}}
+  // CHECK: [[@LINE+1]]:137: error: expected fix-it not seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
   labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=xx}}
 
-  // CHECK: [[@LINE+1]]:124: error: expected no fix-its; actual fix-its seen: {{{{}}15-18=aa}} {{{{}}23-26=bb}}
+  // CHECK: [[@LINE+1]]:124: error: expected no fix-its; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
   labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{none}}
 
-  // CHECK: [[@LINE+1]]:137: error: unexpected fix-it seen; actual fix-its seen: {{{{}}15-18=aa}} {{{{}}23-26=bb}}
+  // CHECK: [[@LINE+1]]:137: error: unexpected fix-it seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
   labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{none}}
 
   labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=bb}} {{none}}
 
-  // CHECK: [[@LINE+1]]:137: error: expected fix-it not seen; actual fix-its seen: {{{{}}15-18=aa}} {{{{}}23-26=bb}}
+  // CHECK: [[@LINE+1]]:137: error: expected fix-it not seen; actual fix-its seen: {{\{\{}}15-18=aa}} {{\{\{}}23-26=bb}}
   labeledFunc(aax: 0, bbx: 1) // expected-error {{incorrect argument labels in call (have 'aax:bbx:', expected 'aa:bb:')}} {{15-18=aa}} {{23-26=xx}} {{none}}
 }
diff --git a/test/IRGen/class_field_other_module.swift b/test/IRGen/class_field_other_module.swift
index 9bea86f328409..b74db17246396 100644
--- a/test/IRGen/class_field_other_module.swift
+++ b/test/IRGen/class_field_other_module.swift
@@ -3,11 +3,14 @@
 // RUN: %target-swift-frontend -emit-module -emit-module-path=%t/other_class.swiftmodule %S/Inputs/other_class.swift
 // RUN: %target-swift-frontend -I %t -emit-ir -O -enforce-exclusivity=unchecked %s | %FileCheck %s -DINT=i%target-ptrsize
 
+// REQUIRES: PTRSIZE=64
+
 import other_class
 
 // CHECK-LABEL: define {{(protected )?}}{{(dllexport )?}}swiftcc i32 @"$s24class_field_other_module12getSubclassXys5Int32V0c1_A00F0CF"(ptr nocapture readonly %0)
 // CHECK-NEXT: entry:
-// CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds %T11other_class5OtherC, ptr %0, [[INT]] 0, i32 1
+// An Int32 after the heap object header
+// CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, ptr %0, i64 16
 // CHECK-NEXT: [[RESULT:%.*]] = load i32, ptr [[GEP]]
 // CHECK-NEXT: ret i32 [[RESULT]]
 public func getSubclassX(_ o: Subclass) -> Int32 {
@@ -16,7 +19,8 @@ public func getSubclassX(_ o: Subclass) -> Int32 {
 
 // CHECK-LABEL: define {{(protected )?}}{{(dllexport )?}}swiftcc i32 @"$s24class_field_other_module12getSubclassYys5Int32V0c1_A00F0CF"(ptr nocapture readonly %0)
 // CHECK-NEXT: entry:
-// CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds %T11other_class8SubclassC, ptr %0, [[INT]] 0, i32 2
+// An Int32 after an Int32 after the heap object header
+// CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, ptr %0, i64 20
 // CHECK-NEXT: [[RESULT:%.*]] = load i32, ptr [[GEP]]
 // CHECK-NEXT: ret i32 [[RESULT]]
 public func getSubclassY(_ o: Subclass) -> Int32 {
diff --git a/test/IRGen/dllexport.swift b/test/IRGen/dllexport.swift
index dc764bfbcef45..836cc85139bdc 100644
--- a/test/IRGen/dllexport.swift
+++ b/test/IRGen/dllexport.swift
@@ -37,7 +37,7 @@ open class d {
 // CHECK-DAG: define dllexport swiftcc ptr @"$s9dllexport1cCfd"(ptr{{.*}})
 // CHECK-DAG-NO-OPT: define dllexport swiftcc ptr @"$s9dllexport1cCACycfc"(ptr %0)
 // CHECK-DAG-NO-OPT: define dllexport swiftcc ptr @"$s9dllexport1cCACycfC"(ptr %0)
-// CHECK-DAG: define dllexport swiftcc {{(nonnull )?}}ptr @"$s9dllexport2ciAA1cCvau"()
+// CHECK-DAG: define dllexport swiftcc {{(noundef )?(nonnull )?}}ptr @"$s9dllexport2ciAA1cCvau"()
 // CHECK-DAG-NO-OPT: define dllexport swiftcc void @"$s9dllexport1dC1m33_C57BA610BA35E21738CC992438E660E9LLyyF"(ptr %0)
 // CHECK-DAG-NO-OPT: define dllexport swiftcc void @"$s9dllexport1dCfD"(ptr %0)
 // CHECK-DAG: define dllexport swiftcc ptr @"$s9dllexport1dCfd"(ptr{{.*}})
diff --git a/test/IRGen/entrypoint-section-run-main_swift.cpp b/test/IRGen/entrypoint-section-run-main_swift.cpp
index a83299ab88e5e..0e43b2f7a14ff 100644
--- a/test/IRGen/entrypoint-section-run-main_swift.cpp
+++ b/test/IRGen/entrypoint-section-run-main_swift.cpp
@@ -24,6 +24,13 @@ using mach_header_platform = mach_header_64;
 using mach_header_platform = mach_header;
 #endif
 
+#if __has_feature(ptrauth_function_pointer_type_discrimination)
+#define my_ptrauth_function_pointer_type_discriminator(__type) \
+  __builtin_ptrauth_type_discriminator(__type)
+#else
+#define my_ptrauth_function_pointer_type_discriminator(__type) ((ptrauth_extra_data_t)0)
+#endif
+
 int main(int argc, char *argv[]) {
   if (argc != 2) {
     printf("no argument!\n");
@@ -67,7 +74,7 @@ int main(int argc, char *argv[]) {
               reinterpret_cast<long>(data) + offset
           ),
           ptrauth_key_function_pointer,
-          ptrauth_function_pointer_type_discriminator(MainFunction)
+          my_ptrauth_function_pointer_type_discriminator(MainFunction)
       )
     );
 
diff --git a/test/IRGen/entrypoint-section-run.cpp b/test/IRGen/entrypoint-section-run.cpp
index 22c47354fe3a9..a429f5896f9f9 100644
--- a/test/IRGen/entrypoint-section-run.cpp
+++ b/test/IRGen/entrypoint-section-run.cpp
@@ -23,6 +23,13 @@ using mach_header_platform = mach_header_64;
 using mach_header_platform = mach_header;
 #endif
 
+#if __has_feature(ptrauth_function_pointer_type_discrimination)
+#define my_ptrauth_function_pointer_type_discriminator(__type) \
+  __builtin_ptrauth_type_discriminator(__type)
+#else
+#define my_ptrauth_function_pointer_type_discriminator(__type) ((ptrauth_extra_data_t)0)
+#endif
+
 int main(int argc, char *argv[]) {
   if (argc != 2) {
     printf("no argument!\n");
@@ -66,7 +73,7 @@ int main(int argc, char *argv[]) {
               reinterpret_cast<long>(data) + offset
           ),
           ptrauth_key_function_pointer,
-          ptrauth_function_pointer_type_discriminator(MainFunction)
+          my_ptrauth_function_pointer_type_discriminator(MainFunction)
       )
     );
 
diff --git a/test/IRGen/enum_singleton.swift b/test/IRGen/enum_singleton.swift
index 0df76406a196b..66f940619fbb3 100644
--- a/test/IRGen/enum_singleton.swift
+++ b/test/IRGen/enum_singleton.swift
@@ -41,7 +41,7 @@ public enum SingletonEnum {
 // CHECK-OPT:   ret void
 // CHECK: }
 
-// CHECK: define internal i32 @"$s14enum_singleton13SingletonEnumOwug"
+// CHECK: define internal{{.*}} i32 @"$s14enum_singleton13SingletonEnumOwug"
 // CHECK:   ret i32 0
 // CHECK: }
 
diff --git a/test/IRGen/has_symbol.swift b/test/IRGen/has_symbol.swift
index a0c5d72237f55..2a9025953b2a2 100644
--- a/test/IRGen/has_symbol.swift
+++ b/test/IRGen/has_symbol.swift
@@ -55,11 +55,13 @@ public func testGlobalFunctions() {
 
 // --- funcWithOpaqueResult() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper20funcWithOpaqueResultQryFTwS"()
-// CHECK:   ret i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper20funcWithOpaqueResultQryFQOMQ", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper20funcWithOpaqueResultQryF", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper20funcWithOpaqueResultQryFQOMQ", ptr null), icmp ne (ptr @"$s17has_symbol_helper20funcWithOpaqueResultQryF", ptr null)
+// CHECK:   ret i1 %0
 
 // --- cdeclFunc() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper9cdeclFuncyyFTwS"()
-// CHECK:   ret i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper9cdeclFuncyyF", ptr null), i1 icmp ne (ptr @cdecl_func, ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper9cdeclFuncyyF", ptr null), icmp ne (ptr @cdecl_func, ptr null)
+// CHECK:   ret i1 %0
 
 // --- forwardDeclaredFunc() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper19forwardDeclaredFuncyyFTwS"()
@@ -67,19 +69,33 @@ public func testGlobalFunctions() {
 
 // --- dynamicFunc() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper11dynamicFuncyyFTwS"()
-// CHECK:   ret i1 and (i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper11dynamicFuncyyF", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper11dynamicFuncyyFTX", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper11dynamicFuncyyFTx", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper11dynamicFuncyyF", ptr null), icmp ne (ptr @"$s17has_symbol_helper11dynamicFuncyyFTX", ptr null)
+// CHECK:   %1 = and i1 %0, icmp ne (ptr @"$s17has_symbol_helper11dynamicFuncyyFTx", ptr null)
+// CHECK:   ret i1 %1
 
 // --- replacementFunc() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper15replacementFuncyyFTwS"()
-// CHECK:   ret i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper15replacementFuncyyF", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper15replacementFuncyyFTX", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper15replacementFuncyyF", ptr null), icmp ne (ptr @"$s17has_symbol_helper15replacementFuncyyFTX", ptr null)
+// CHECK:   ret i1 %0
 
 // --- dynamicFuncOpaqueResult() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFTwS"()
-// CHECK:   ret i1 and (i1 and (i1 and (i1 and (i1 and (i1 and (i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFQOMQ", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFQOMg", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFQOMh", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFQOMg", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFQOMg", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryF", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFTX", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFTx", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFQOMQ", ptr null), icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFQOMg", ptr null)
+// CHECK:   %1 = and i1 %0, icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFQOMh", ptr null)
+// CHECK:   %2 = and i1 %1, icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFQOMg", ptr null)
+// CHECK:   %3 = and i1 %2, icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFQOMg", ptr null)
+// CHECK:   %4 = and i1 %3, icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryF", ptr null)
+// CHECK:   %5 = and i1 %4, icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFTX", ptr null)
+// CHECK:   %6 = and i1 %5, icmp ne (ptr @"$s17has_symbol_helper23dynamicFuncOpaqueResultQryFTx", ptr null)
+// CHECK:   ret i1 %6
 
 // --- replacementFuncOpaqueResult() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper27replacementFuncOpaqueResultQryFTwS"()
-// CHECK:   ret i1 and (i1 and (i1 and (i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper27replacementFuncOpaqueResultQryFQOMQ", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper27replacementFuncOpaqueResultQryFQOMg", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper27replacementFuncOpaqueResultQryFQOMg", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper27replacementFuncOpaqueResultQryF", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper27replacementFuncOpaqueResultQryFTX", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper27replacementFuncOpaqueResultQryFQOMQ", ptr null), icmp ne (ptr @"$s17has_symbol_helper27replacementFuncOpaqueResultQryFQOMg", ptr null)
+// CHECK:   %1 = and i1 %0, icmp ne (ptr @"$s17has_symbol_helper27replacementFuncOpaqueResultQryFQOMg", ptr null)
+// CHECK:   %2 = and i1 %1, icmp ne (ptr @"$s17has_symbol_helper27replacementFuncOpaqueResultQryF", ptr null)
+// CHECK:   %3 = and i1 %2, icmp ne (ptr @"$s17has_symbol_helper27replacementFuncOpaqueResultQryFTX", ptr null)
+// CHECK:   ret i1 %3
 
 public func testVars() {
   // CHECK: %{{[0-9]+}} = call i1 @"$s17has_symbol_helper6globalSivpTwS"()
@@ -100,11 +116,13 @@ public func testClass(_ c: C) {
 
 // --- C.init() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper1CCACycfcTwS"()
-// CHECK:   ret i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper1CCACycfc", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper1CCACycfC", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper1CCACycfc", ptr null), icmp ne (ptr @"$s17has_symbol_helper1CCACycfC", ptr null)
+// CHECK:   ret i1 %0
 
 // --- C.method(with:) ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper1CC6method4withySi_tFTwS"()
-// CHECK:   ret i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper1CC6method4withySi_tFTj", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper1CC6method4withySi_tFTq", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper1CC6method4withySi_tFTj", ptr null), icmp ne (ptr @"$s17has_symbol_helper1CC6method4withySi_tFTq", ptr null)
+// CHECK:   ret i1 %0
 
 public func testStruct(_ s: S) {
   // CHECK: %{{[0-9]+}} = call i1 @"$s17has_symbol_helper1SV6memberSivpTwS"()
@@ -116,7 +134,10 @@ public func testStruct(_ s: S) {
 
 // --- S.member ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper1SV6memberSivpTwS"()
-// CHECK:   ret i1 and (i1 and (i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper1SV6memberSivpMV", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper1SV6memberSivg", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper1SV6memberSivs", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper1SV6memberSivM", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper1SV6memberSivpMV", ptr null), icmp ne (ptr @"$s17has_symbol_helper1SV6memberSivg", ptr null)
+// CHECK:   %1 = and i1 %0, icmp ne (ptr @"$s17has_symbol_helper1SV6memberSivs", ptr null)
+// CHECK:   %2 = and i1 %1, icmp ne (ptr @"$s17has_symbol_helper1SV6memberSivM", ptr null)
+// CHECK:   ret i1 %2
 
 // --- S.method(with:) ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper1SV6method4withySi_tFTwS"()
@@ -169,4 +190,6 @@ public func testMetatypes() {
 
 // --- S.self ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper1SVTwS"()
-// CHECK:   ret i1 and (i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper1SVMn", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper1SVN", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper1SVMa", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper1SVMn", ptr null), icmp ne (ptr @"$s17has_symbol_helper1SVN", ptr null)
+// CHECK:   %1 = and i1 %0, icmp ne (ptr @"$s17has_symbol_helper1SVMa", ptr null)
+// CHECK:   ret i1 %1
diff --git a/test/IRGen/has_symbol_async.swift b/test/IRGen/has_symbol_async.swift
index abef30caa448f..cb39dd5cefa3d 100644
--- a/test/IRGen/has_symbol_async.swift
+++ b/test/IRGen/has_symbol_async.swift
@@ -17,7 +17,8 @@ public func testGlobalFunctions() {
 
 // --- asyncFunc() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper9asyncFuncyyYaFTwS"()
-// CHECK:   ret i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper9asyncFuncyyYaF", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper9asyncFuncyyYaFTu", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper9asyncFuncyyYaF", ptr null), icmp ne (ptr @"$s17has_symbol_helper9asyncFuncyyYaFTu", ptr null)
+// CHECK:   ret i1 %0
 
 // --- isolatedFunc() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper12isolatedFuncyyFTwS"()
@@ -35,8 +36,11 @@ public func testActor(_ a: A) {
 
 // --- A.init() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper1ACACycfcTwS"()
-// CHECK:   ret i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper1ACACycfc", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper1ACACycfC", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper1ACACycfc", ptr null), icmp ne (ptr @"$s17has_symbol_helper1ACACycfC", ptr null)
+// CHECK:   ret i1 %0
 
 // --- A.asyncMethod() ---
 // CHECK: define linkonce_odr hidden i1 @"$s17has_symbol_helper1AC11asyncMethodyyYaFTwS"()
-// CHECK:   ret i1 and (i1 and (i1 icmp ne (ptr @"$s17has_symbol_helper1AC11asyncMethodyyYaFTj", ptr null), i1 icmp ne (ptr @"$s17has_symbol_helper1AC11asyncMethodyyYaFTjTu", ptr null)), i1 icmp ne (ptr @"$s17has_symbol_helper1AC11asyncMethodyyYaFTq", ptr null))
+// CHECK:   %0 = and i1 icmp ne (ptr @"$s17has_symbol_helper1AC11asyncMethodyyYaFTj", ptr null), icmp ne (ptr @"$s17has_symbol_helper1AC11asyncMethodyyYaFTjTu", ptr null)
+// CHECK:   %1 = and i1 %0, icmp ne (ptr @"$s17has_symbol_helper1AC11asyncMethodyyYaFTq", ptr null)
+// CHECK:   ret i1 %1
diff --git a/test/IRGen/large_argument_result_c.swift b/test/IRGen/large_argument_result_c.swift
index 07d3f30d1ff86..c90042fbd4b66 100644
--- a/test/IRGen/large_argument_result_c.swift
+++ b/test/IRGen/large_argument_result_c.swift
@@ -16,7 +16,7 @@
 // CHECK:  call void @pass_and_return(ptr {{.*}} [[CALL_ALLOCA]], ptr nonnull [[TMP_ALLOCA]], ptr nonnull [[TMP_ALLOCA2]])
 // CHECK:  call {{.*}} @swift_allocObject
 // CHECK:  [[BOX:%.*]] = call noalias ptr @swift_allocObject(
-// CHECK:  [[ADDR_IN_BOX:%.*]] = getelementptr inbounds <{ %swift.refcounted, [128 x i8] }>, ptr [[BOX]], i64 0, i32 1
+// CHECK:  [[ADDR_IN_BOX:%.*]] = getelementptr inbounds i8, ptr [[BOX]], i64 16
 // CHECK:  call void @llvm.memcpy.p0.p0.i64(ptr {{.*}} [[ADDR_IN_BOX]], ptr {{.*}} [[CALL_ALLOCA]], i64 128, i1 false)
 // CHECK:  call void @llvm.lifetime.end.p0(i64 128, ptr nonnull [[CALL_ALLOCA]])
 public func runTest(_ l : large_thing) {
diff --git a/test/IRGen/large_argument_result_c_x86_64.swift b/test/IRGen/large_argument_result_c_x86_64.swift
index 7624d8b00849b..be69a0c5e09af 100644
--- a/test/IRGen/large_argument_result_c_x86_64.swift
+++ b/test/IRGen/large_argument_result_c_x86_64.swift
@@ -15,7 +15,7 @@
 // CHECK:  call void @pass_and_return(ptr {{.*}} [[CALL_ALLOCA]], ptr nonnull byval{{.*}} %0, ptr nonnull byval{{.*}} %0)
 // CHECK:  call {{.*}} @swift_allocObject
 // CHECK:  [[BOX:%.*]] = {{.*}}call noalias ptr @swift_allocObject(
-// CHECK:  [[ADDR_IN_BOX:%.*]] = getelementptr inbounds <{ %swift.refcounted, [128 x i8] }>, ptr [[BOX]], i64 0, i32 1
+// CHECK:  [[ADDR_IN_BOX:%.*]] = getelementptr inbounds i8, ptr [[BOX]], i64 16
 // CHECK:  call void @llvm.memcpy.p0.p0.i64(ptr {{.*}} [[ADDR_IN_BOX]], ptr {{.*}} [[CALL_ALLOCA]], i64 128, i1 false)
 // CHECK:  call void @llvm.lifetime.end.p0(i64 128, ptr nonnull [[CALL_ALLOCA]])
 public func runTest(_ l : large_thing) {
diff --git a/test/IRGen/non_fixed_return.swift b/test/IRGen/non_fixed_return.swift
index 18d08cf30a91f..ec84250f3e596 100644
--- a/test/IRGen/non_fixed_return.swift
+++ b/test/IRGen/non_fixed_return.swift
@@ -64,8 +64,8 @@ func create<T>(_ t: T) -> C<T> {
 // Make sure we don't loose the stores for the optional UInt32? in optimize mode.
 // OPT-LABEL: define hidden swiftcc void @"$s16non_fixed_return1CVACyxGycfC"(ptr noalias sret(%swift.opaque) %0
 // OPT:  store i32 0, ptr [[BASE:%[0-9]+]]
-// OPT:  [[ADDR2:%.*]] = getelementptr inbounds %Ts6UInt32VSg, ptr [[BASE]], i64 0, i32 1
+// OPT:  [[ADDR2:%.*]] = getelementptr inbounds i8, ptr [[BASE]], i64 4
 // OPT:  store i1 true, ptr [[ADDR2]]
-// OPT:  [[ADDR4:%.*]] = getelementptr inbounds %T16non_fixed_return1BV, ptr [[BASE]], i64 0, i32 2
+// OPT:  [[ADDR4:%.*]] = getelementptr inbounds i8, ptr [[BASE]], i64 8
 // OPT: call void @llvm.memset.p0.i64(ptr {{.*}}[[ADDR4]], i8 0, i64 16, i1 false)
 // OPT: ret void
diff --git a/test/IRGen/objc_local.swift b/test/IRGen/objc_local.swift
index d20e087b0d6f7..5b1a45ddb53c4 100644
--- a/test/IRGen/objc_local.swift
+++ b/test/IRGen/objc_local.swift
@@ -8,7 +8,7 @@
 import Foundation
 
 func foo() -> Int64 {
-  // CHECK-LABEL: define internal i64 @"$s10objc_local3foos5Int64VyF3BarL_C10returnFiveADyFTo"
+  // CHECK-LABEL: define internal{{( noundef)?}} i64 @"$s10objc_local3foos5Int64VyF3BarL_C10returnFiveADyFTo"
   class Bar: NSObject {
     @objc func returnFive() -> Int64 { return 6 }
   }
diff --git a/test/IRGen/recursion_infinite_optimized.sil b/test/IRGen/recursion_infinite_optimized.sil
index ee0d26fed0dcc..fe8a676859fd3 100644
--- a/test/IRGen/recursion_infinite_optimized.sil
+++ b/test/IRGen/recursion_infinite_optimized.sil
@@ -13,7 +13,7 @@ bb0(%arg : $Int):
   return %res : $Int
 }
 
-// CHECK: define{{.*}} swiftcc [[T:i[0-9]+]] @rec([[T]] %0) #0 {
+// CHECK: define{{.*}} swiftcc{{( noundef)?}} [[T:i[0-9]+]] @rec([[T]] %0) #0 {
 // CHECK-NEXT: entry:
 // CHECK-NEXT: br label %tailrecurse
 // CHECK-EMPTY:
diff --git a/test/IRGen/struct_with_resilient_type.swift b/test/IRGen/struct_with_resilient_type.swift
index 91cdf93c7eae6..20bc54a4cfa0b 100644
--- a/test/IRGen/struct_with_resilient_type.swift
+++ b/test/IRGen/struct_with_resilient_type.swift
@@ -49,12 +49,12 @@ crashCaller()
 // VWT-macosx:   store i64 [[VAL1]]
 // VWT-macosx:   [[T1:%.*]] = tail call swiftcc %swift.metadata_response @"$s16resilient_struct13ResilientBoolVMa"(i64 0)
 // VWT-macosx:   [[T2:%.*]] = extractvalue %swift.metadata_response [[T1]], 0
-// VWT-macosx:   [[T3:%.*]] = getelementptr inbounds ptr, ptr [[T2]], i64 -1
+// VWT-macosx:   [[T3:%.*]] = getelementptr inbounds i8, ptr [[T2]], i64 -8
 // VWT-macosx:   [[T5:%.*]] = load ptr, ptr [[T3]]
-// VWT-macosx:   [[T6:%.*]] = getelementptr inbounds ptr, ptr [[T5]], i64 5
+// VWT-macosx:   [[T6:%.*]] = getelementptr inbounds i8, ptr [[T5]], i64 4
 // VWT-macosx:   [[T8:%.*]] = load ptr, ptr [[T6]]
 // VWT-macosx:   tail call ptr [[T8]](
-// VWT-macosx:   [[F01:%.*]] = getelementptr inbounds i32, ptr [[MT]], i64 6
+// VWT-macosx:   [[F01:%.*]] = getelementptr inbounds i8, ptr [[MT]], i64 24
 // VWT-macosx:   [[F03:%.*]] = load i32, ptr [[F01]], align 8
 // VWT-macosx:   [[F04:%.*]] = sext i32 [[F03]] to i64
 // VWT-macosx:   [[FA1:%.*]] = getelementptr inbounds i8, ptr {{.*}}, i64 [[F04]]
diff --git a/test/IRGen/typelayout_based_value_witness.swift b/test/IRGen/typelayout_based_value_witness.swift
index 97af3213ab8cd..f16626c0617cc 100644
--- a/test/IRGen/typelayout_based_value_witness.swift
+++ b/test/IRGen/typelayout_based_value_witness.swift
@@ -2,6 +2,8 @@
 // RUN: %target-swift-frontend -enable-type-layout -primary-file %s -O -emit-ir | %FileCheck %s --check-prefix=OPT --check-prefix=OPT-%target-ptrsize
 // RUN: %target-swift-frontend -primary-file %s -emit-ir | %FileCheck %s --check-prefix=NOTL
 
+// REQUIRES: PTRSIZE=64
+
 public struct B<T> {
   var x: T
   var y: T
@@ -80,20 +82,20 @@ public enum ForwardEnum<T> {
 
 
 // OPT: define{{.*}} void @"$s30typelayout_based_value_witness1AVwxx"(ptr noalias %object, ptr nocapture readonly %"A<T>")
-// OPT:   [[T_PARAM:%.*]] = getelementptr inbounds ptr, ptr %"A<T>", {{(i64|i32)}} 2
+// OPT:   [[T_PARAM:%.*]] = getelementptr inbounds i8, ptr %"A<T>", i64 16
 // OPT:   [[T:%.*]] = load ptr, ptr [[T_PARAM]]
-// OPT:   [[VWT_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[T]], {{(i64|i32)}} -1
+// OPT:   [[VWT_ADDR:%.*]] = getelementptr inbounds i8, ptr [[T]], {{(i64|i32)}} -8
 // OPT:   [[VWT:%.*]] = load ptr, ptr [[VWT_ADDR]]
-// OPT:   [[DESTROY_VW:%.*]] = getelementptr inbounds ptr, ptr [[VWT]], {{(i64|i32)}} 1
+// OPT:   [[DESTROY_VW:%.*]] = getelementptr inbounds i8, ptr [[VWT]], {{(i64|i32)}} 8
 // OPT:   [[DESTROY:%.*]] = load ptr, ptr [[DESTROY_VW]]
 // OPT:   tail call void [[DESTROY]](ptr noalias %object, ptr [[T]])
-// OPT:   [[SIZE_VW:%.*]] = getelementptr inbounds %swift.vwtable, ptr [[VWT]], {{i64|i32}} 0, {{(i64|i32)}} 8
+// OPT:   [[SIZE_VW:%.*]] = getelementptr inbounds i8, ptr [[VWT]], {{(i64|i32)}} 64
 // OPT:   [[SIZE_T:%.*]] = load {{(i64|i32)}}, ptr [[SIZE_VW]]
 // OPT:   [[OBJECT:%.*]] = ptrtoint ptr %object to {{(i64|i32)}}
-// OPT:   [[FLAGS_VW:%.*]] = getelementptr inbounds {{.*}}, ptr [[VWT]], {{i64|i32}} 0, {{(i64|i32)}} 10
+// OPT:   [[FLAGS_VW:%.*]] = getelementptr inbounds i8, ptr [[VWT]], {{(i64|i32)}} 80
 // OPT:   [[FLAGS3:%.*]] = load i32, ptr [[FLAGS_VW]]
 // OPT:   [[FLAGS:%.*]] = and i32 [[FLAGS3]], 255
-// OPT-64:   %flags.alignmentMask = zext i32 [[FLAGS]] to i64
+// OPT-64:   %flags.alignmentMask = zext nneg i32 [[FLAGS]] to i64
 // OPT-64:   [[TMP:%.*]] = add {{(i64|i32)}} [[SIZE_T]], %flags.alignmentMask
 // OPT-32:   [[TMP:%.*]] = add {{(i64|i32)}} %flags.alignmentMask, [[SIZE_T]]
 // OPT:   [[TMP2:%.*]] = add {{(i64|i32)}} [[TMP]], [[OBJECT]]
diff --git a/test/IRGen/variadic_generic_functions.sil b/test/IRGen/variadic_generic_functions.sil
index 3737ce93d186a..0d8257698e285 100644
--- a/test/IRGen/variadic_generic_functions.sil
+++ b/test/IRGen/variadic_generic_functions.sil
@@ -126,13 +126,13 @@ sil @associatedtype_with_added_conformance_2_callee : $<each T : R> () -> () {}
 // CHECK-SAME:        ptr %"each T",
 // CHECK-SAME:        ptr %"each T.Q")
 // CHECK:             [[GEN2_TYPES:%[^,]+]] = alloca ptr, [[INT]] [[SHAPE]]
-// CHECK:             [[STORED_STACK_LOC:%[^,]+]] = call ptr @llvm.stacksave()
+// CHECK:             [[STORED_STACK_LOC:%[^,]+]] = call ptr @llvm.stacksave.p0()
 // CHECK:             [[GEN2_CONFORMANCES_TO_Q:%[^,]+]] = alloca ptr, [[INT]] [[SHAPE]]
 // CHECK:             call swiftcc void @associatedtype_with_forwarded_conformance_1_callee(
 // CHECK-SAME:            [[INT]] [[SHAPE]],
 // CHECK-SAME:            ptr [[GEN2_TYPES]],
 // CHECK-SAME:            ptr [[GEN2_CONFORMANCES_TO_Q]])
-// CHECK:             call void @llvm.stackrestore(ptr [[STORED_STACK_LOC]])
+// CHECK:             call void @llvm.stackrestore.p0(ptr [[STORED_STACK_LOC]])
 sil @associatedtype_with_forwarded_conformance_1 : $<each T : Q> () -> () {
     %i = function_ref @associatedtype_with_forwarded_conformance_1_callee : $@convention(thin) <each T : Q> () -> ()
     apply %i<Pack{repeat Gen2<each T>}>() : $@convention(thin) <each T : Q> () -> ()
@@ -149,14 +149,14 @@ sil @associatedtype_with_forwarded_conformance_1_callee : $<each T : Q> () -> ()
 // CHECK-SAME:        ptr %"each T.PA",
 // CHECK-SAME:        ptr %"(each T).A.Q")
 // CHECK:         [[GEN1_TYPES:%[^,]+]] = alloca ptr, [[INT]] [[SHAPE]]
-// CHECK:         [[STORED_STACK_LOC:%[^,]+]] = call ptr @llvm.stacksave()
+// CHECK:         [[STORED_STACK_LOC:%[^,]+]] = call ptr @llvm.stacksave.p0()
 // CHECK:         [[GEN1_CONFORMANCES_TO_PA:%[^,]+]] = alloca ptr, [[INT]] [[SHAPE]]
 // CHECK:         call swiftcc void @generictype_with_forwarded_conformance_2_callee(
 // CHECK-SAME:        [[INT]] [[SHAPE]],
 // CHECK-SAME:        ptr [[GEN1_TYPES]],
 // CHECK-SAME:        ptr [[GEN1_CONFORMANCES_TO_PA]],
 // CHECK-SAME:        ptr %"(each T).A.Q")
-// CHECK:         call void @llvm.stackrestore(ptr [[STORED_STACK_LOC]])
+// CHECK:         call void @llvm.stackrestore.p0(ptr [[STORED_STACK_LOC]])
 sil @generictype_with_forwarded_conformance_2 : $<each T : PA where repeat (each T).A : Q>() -> () {
     %callee = function_ref @generictype_with_forwarded_conformance_2_callee : $@convention(thin) <each T : PA where repeat (each T).A : Q> () -> ()
     apply %callee<Pack{repeat Gen1<each T>}>() : $@convention(thin) <each T : PA where repeat (each T).A : Q> () -> ()
@@ -172,14 +172,14 @@ sil @generictype_with_forwarded_conformance_2_callee : $<each T : PA where repea
 // CHECK-SAME:        ptr %"each T.PA",
 // CHECK-SAME:        ptr %"(each T).A.Q")
 // CHECK:         [[GEN1_GEN1_TYPES:%[^,]+]] = alloca ptr, [[INT]] [[SHAPE]]
-// CHECK:         [[STORED_STACK_LOC:%[^,]+]] = call ptr @llvm.stacksave()
+// CHECK:         [[STORED_STACK_LOC:%[^,]+]] = call ptr @llvm.stacksave.p0()
 // CHECK:         [[GEN1_GEN1_CONFORMANCES_TO_PA:%[^,]+]] = alloca ptr, [[INT]] [[SHAPE]]
 // CHECK:         call swiftcc void @generic_with_forwarded_conformance_3_callee(
 // CHECK-SAME:        [[INT]] [[SHAPE]],
 // CHECK-SAME:        ptr [[GEN1_GEN1_TYPES]],
 // CHECK-SAME:        ptr [[GEN1_GEN1_CONFORMANCES_TO_PA]],
 // CHECK-SAME:        ptr %"(each T).A.Q")
-// CHECK:         call void @llvm.stackrestore(ptr [[STORED_STACK_LOC]])
+// CHECK:         call void @llvm.stackrestore.p0(ptr [[STORED_STACK_LOC]])
 sil @generic_with_forwarded_conformance_3 : $<each T : PA where repeat (each T).A : Q> () -> () {
     %callee = function_ref @generic_with_forwarded_conformance_3_callee : $@convention(thin) <each T : PA where repeat (each T).A : Q> () -> ()
     apply %callee<Pack{repeat Gen1<Gen1<each T>>}>() : $@convention(thin) <each T : PA where repeat (each T).A : Q> () -> ()
diff --git a/test/IRGen/variadic_generics.sil b/test/IRGen/variadic_generics.sil
index 3fb598b5e6b8c..4876fe99b1d17 100644
--- a/test/IRGen/variadic_generics.sil
+++ b/test/IRGen/variadic_generics.sil
@@ -105,9 +105,9 @@ bb0(%pack : $*Pack{Int, repeat each T, Int}, %value : $Int):
 // CHECK-LABEL: define {{.*}}@test_pack_alloc_1_dynamic(
 // CHECK-SAME:       [[INT]] [[PACK_SIZE:%[^,]+]]
 // CHECK:        [[SIZE:%[^,]+]] = add [[INT]] [[PACK_SIZE]], [[PACK_SIZE]]
-// CHECK:        [[SP_SAVE:%[^,]+]] = call ptr @llvm.stacksave()
+// CHECK:        [[SP_SAVE:%[^,]+]] = call ptr @llvm.stacksave.p0()
 // CHECK:        alloca ptr, [[INT]] [[SIZE]]
-// CHECK:        call void @llvm.stackrestore(ptr [[SP_SAVE]])
+// CHECK:        call void @llvm.stackrestore.p0(ptr [[SP_SAVE]])
 sil @test_pack_alloc_1_dynamic : $<each T> () -> () {
 // Control flow so that stack saving/restoring is emitted
 entry:
diff --git a/test/Interop/Cxx/class/method/methods-this-and-indirect-return-irgen-itanium.swift b/test/Interop/Cxx/class/method/methods-this-and-indirect-return-irgen-itanium.swift
index cc722ffb5e9d9..2cbba9a6571b6 100644
--- a/test/Interop/Cxx/class/method/methods-this-and-indirect-return-irgen-itanium.swift
+++ b/test/Interop/Cxx/class/method/methods-this-and-indirect-return-irgen-itanium.swift
@@ -14,4 +14,4 @@ public func use() -> CInt {
 // CHECK: %[[result:.*]] = alloca %TSo19NonTrivialInWrapperV
 // CHECK: call void @_ZN10HasMethods28nonConstPassThroughAsWrapperEi(ptr noalias sret(%TSo19NonTrivialInWrapperV) %[[result]], ptr %[[instance]], i32 42)
 
-// CHECK: define {{.*}} void @_ZN10HasMethods28nonConstPassThroughAsWrapperEi(ptr noalias sret(%struct.NonTrivialInWrapper) {{.*}} %{{.*}}, ptr {{.*}} %{{.*}}, i32 noundef %{{.*}})
+// CHECK: define {{.*}} void @_ZN10HasMethods28nonConstPassThroughAsWrapperEi(ptr noalias sret(%struct.NonTrivialInWrapper) {{.*}} %{{.*}}, ptr {{.*}} %{{.*}}, i32{{( noundef)?}} %{{.*}})
diff --git a/test/Serialization/load-target-normalization.swift b/test/Serialization/load-target-normalization.swift
index 50b42addef435..09f3483219a13 100644
--- a/test/Serialization/load-target-normalization.swift
+++ b/test/Serialization/load-target-normalization.swift
@@ -1,10 +1,6 @@
 // RUN: %empty-directory(%t/ForeignModule.swiftmodule)
 // RUN: touch %t/ForeignModule.swiftmodule/garbage-garbage-garbage.swiftmodule
 
-// https://github.com/apple/swift/issues/54797
-// This test crashes on 'next' branch.
-// XFAIL: asserts
-
 // Test format: We try to import ForeignModule with architectures besides
 // garbage-garbage-garbage and check the target triple listed in the error
 // message to make sure it was normalized correctly. This works in lieu of a
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp b/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp
index cc11e3b15e124..b3f9be68d82a7 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp
@@ -864,7 +864,7 @@ static void setLocationInfoForClangNode(ClangNode ClangNode,
   std::pair<clang::FileID, unsigned> Decomp =
       ClangSM.getDecomposedLoc(CharRange.getBegin());
   if (!Decomp.first.isInvalid()) {
-    if (auto FE = ClangSM.getFileEntryForID(Decomp.first)) {
+    if (auto FE = ClangSM.getFileEntryRefForID(Decomp.first)) {
       Location.Filename = FE->getName();
 
       std::pair<clang::FileID, unsigned> EndDecomp =
@@ -1351,7 +1351,7 @@ getClangDeclarationName(const clang::NamedDecl *ND, NameTranslatingInfo &Info) {
       return clang::DeclarationName();
 
     ArrayRef<StringRef> Args = llvm::ArrayRef(Info.ArgNames);
-    std::vector<clang::IdentifierInfo *> Pieces;
+    std::vector<const clang::IdentifierInfo *> Pieces;
     for (unsigned i = 0; i < NumPieces; ++i) {
       if (i >= Info.ArgNames.size() || Info.ArgNames[i].empty()) {
         Pieces.push_back(OrigSel.getIdentifierInfoForSlot(i));
diff --git a/tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp b/tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp
index 69cb760afa603..2fc43eade84f2 100644
--- a/tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp
+++ b/tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp
@@ -20,6 +20,7 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 
+using namespace llvm::opt;
 using namespace sourcekitd_test;
 using llvm::StringRef;
 
@@ -28,9 +29,7 @@ namespace {
 // Create enum with OPT_xxx values for each option in Options.td.
 enum Opt {
   OPT_INVALID = 0,
-#define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
-               HELP, META, VALUES)                                             \
-  OPT_##ID,
+#define OPTION(...) LLVM_MAKE_OPT_ID(__VA_ARGS__),
 #include "Options.inc"
   LastOption
 #undef OPTION
@@ -46,12 +45,7 @@ enum Opt {
 
 // Create table mapping all options defined in Options.td.
 static const llvm::opt::OptTable::Info InfoTable[] = {
-#define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
-               HELPTEXT, METAVAR, VALUES)                                      \
-  {PREFIX,      NAME,      HELPTEXT,                                           \
-   METAVAR,     OPT_##ID,  llvm::opt::Option::KIND##Class,                     \
-   PARAM,       FLAGS,     OPT_##GROUP,                                        \
-   OPT_##ALIAS, ALIASARGS, VALUES},
+#define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
 #include "Options.inc"
 #undef OPTION
 };
diff --git a/tools/libMockPlugin/MockPlugin.cpp b/tools/libMockPlugin/MockPlugin.cpp
index 3cd3b42d64c23..2e2b8faeac0ed 100644
--- a/tools/libMockPlugin/MockPlugin.cpp
+++ b/tools/libMockPlugin/MockPlugin.cpp
@@ -203,7 +203,7 @@ int TestRunner::run() {
 
     // Read request data.
     auto request_size = llvm::support::endian::byte_swap(
-        request_header, llvm::support::endianness::little);
+        request_header, llvm::endianness::little);
     llvm::SmallVector<char, 0> request_data;
     request_data.assign(request_size, 0);
     ioSize = fread(request_data.data(), request_size, 1, stdin);
@@ -240,8 +240,9 @@ int TestRunner::run() {
     llvm::SmallVector<char, 0> response_data;
     llvm::raw_svector_ostream(response_data) << response;
     auto response_size = response_data.size();
-    auto response_header = llvm::support::endian::byte_swap<
-        uint64_t, llvm::support::endianness::little>(response_size);
+    auto response_header =
+        llvm::support::endian::byte_swap<uint64_t, llvm::endianness::little>(
+            response_size);
     ioSize = fwrite(&response_header, sizeof(response_header), 1, stdout);
     if (!ioSize) {
       llvm::errs() << "failed to write response header\n";
diff --git a/tools/libSwiftScan/SwiftCaching.cpp b/tools/libSwiftScan/SwiftCaching.cpp
index aedf855423a9f..75b0dd10f1578 100644
--- a/tools/libSwiftScan/SwiftCaching.cpp
+++ b/tools/libSwiftScan/SwiftCaching.cpp
@@ -405,7 +405,7 @@ createCachedCompilation(SwiftScanCAS &CAS, const llvm::cas::CASID &ID,
   auto Input = KeyProxy->getData();
 
   unsigned Index =
-      llvm::support::endian::read<uint32_t, llvm::support::little,
+      llvm::support::endian::read<uint32_t, llvm::endianness::little,
                                   llvm::support::unaligned>(Input.data());
   {
     swift::cas::CompileJobResultSchema Schema(CAS.getCAS());
diff --git a/tools/libSwiftScan/libSwiftScan.cpp b/tools/libSwiftScan/libSwiftScan.cpp
index 7575a2b6a14a1..7312969881304 100644
--- a/tools/libSwiftScan/libSwiftScan.cpp
+++ b/tools/libSwiftScan/libSwiftScan.cpp
@@ -655,9 +655,9 @@ swiftscan_string_set_t *
 swiftscan_compiler_supported_arguments_query() {
   std::unique_ptr<llvm::opt::OptTable> table = swift::createSwiftOptTable();
   std::vector<std::string> frontendFlags;
-#define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
-               HELPTEXT, METAVAR, VALUES)                                      \
-  addFrontendFlagOption(*table, swift::options::OPT_##ID, frontendFlags);
+#define OPTION(...)                                                            \
+  addFrontendFlagOption(*table, swift::options::LLVM_MAKE_OPT_ID(__VA_ARGS__), \
+                        frontendFlags);
 #include "swift/Option/Options.inc"
 #undef OPTION
   return swift::c_string_utils::create_set(frontendFlags);
diff --git a/tools/swift-scan-test/swift-scan-test.cpp b/tools/swift-scan-test/swift-scan-test.cpp
index 663dccdc561b9..4fce9186cbc25 100644
--- a/tools/swift-scan-test/swift-scan-test.cpp
+++ b/tools/swift-scan-test/swift-scan-test.cpp
@@ -279,7 +279,7 @@ int main(int argc, char *argv[]) {
   auto Args = createArgs(SwiftCommands, Saver, Action);
 
   std::atomic<int> Ret = 0;
-  llvm::ThreadPool Pool(llvm::hardware_concurrency(Threads));
+  llvm::StdThreadPool Pool(llvm::hardware_concurrency(Threads));
   for (unsigned i = 0; i < Threads; ++i) {
     Pool.async([&]() {
       switch (Action) {
diff --git a/unittests/DependencyScan/Features.cpp b/unittests/DependencyScan/Features.cpp
index a35315819cb8f..89cdc1b900b46 100644
--- a/unittests/DependencyScan/Features.cpp
+++ b/unittests/DependencyScan/Features.cpp
@@ -45,9 +45,9 @@ TEST_F(ScanTest, TestHasArgumentQuery) {
     optionSet.insert(std::string(data, option.length));
   }
   swiftscan_string_set_dispose(supported_args_set);
-#define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
-               HELPTEXT, METAVAR, VALUES)                                      \
-  testHasOption(*table, swift::options::OPT_##ID, optionSet);
+#define OPTION(...)                                                            \
+  testHasOption(*table, swift::options::LLVM_MAKE_OPT_ID(__VA_ARGS__),         \
+                optionSet);
 #include "swift/Option/Options.inc"
 #undef OPTION
 }
diff --git a/validation-test/IRGen/pack_stack_metadata_alloc_loop.sil b/validation-test/IRGen/pack_stack_metadata_alloc_loop.sil
index e788af1a5a327..10bcbcbebfb9f 100644
--- a/validation-test/IRGen/pack_stack_metadata_alloc_loop.sil
+++ b/validation-test/IRGen/pack_stack_metadata_alloc_loop.sil
@@ -2,6 +2,7 @@
 // RUN: %target-swift-frontend -parse-sil -enable-pack-metadata-stack-promotion=true -emit-ir -primary-file %s | %IRGenFileCheck %s
 
 // REQUIRES: executable_test
+// REQUIRES: CPU=arm64
 
 // Allocate metadata packs on the stack in a loop.  If these packs weren't
 // deallocated, the stack would be exhausted.
@@ -36,11 +37,11 @@ sil @callee : $@convention(thin) <each T> () -> () {
 // CHECK:       [[HEADER]]:
 // CHECK:         [[PREVIOUS:%[^,]+]] = phi i64 [ 10000000, %[[ENTRY]] ], [ [[REMAINING:%[^,]+]], %{{[^,]+}} ]
 // CHECK:         [[COMBINED_PACK_SIZE:%[^,]+]] = add [[INT]] %0, %1
-// CHECK:         [[STACK_BEFORE_FIRST_ALLOCA:%[^,]+]] = call ptr @llvm.stacksave()
+// CHECK:         [[STACK_BEFORE_FIRST_ALLOCA:%[^,]+]] = call ptr @llvm.stacksave.p0()
 // CHECK:         [[FIRST_ALLOCA_METADATA_PACK:%[^,]+]] = alloca ptr, [[INT]] [[COMBINED_PACK_SIZE]]
 // CHECK:         call swiftcc void @callee([[INT]] [[COMBINED_PACK_SIZE]], ptr [[FIRST_ALLOCA_METADATA_PACK]])
 // CHECK:         [[COMBINED_PACK_SIZE_2:%[^,]+]] = add [[INT]] %1, %0
-// CHECK:         [[STACK_BEFORE_SECOND_ALLOCA:%[^,]+]] = call ptr @llvm.stacksave()
+// CHECK:         [[STACK_BEFORE_SECOND_ALLOCA:%[^,]+]] = call ptr @llvm.stacksave.p0()
 // CHECK:         [[SECOND_ALLOCA_METADATA_PACK:%[^,]+]] = alloca ptr, [[INT]] [[COMBINED_PACK_SIZE_2]]
 // CHECK:         call swiftcc void @callee([[INT]] [[COMBINED_PACK_SIZE_2]], ptr [[SECOND_ALLOCA_METADATA_PACK]])
 // CHECK:         [[REMAINING_AND_OVERFLOW:%[^,]+]] = call { i64, i1 } @llvm.ssub.with.overflow.i64(i64 [[PREVIOUS]], i64 1)
@@ -48,12 +49,14 @@ sil @callee : $@convention(thin) <each T> () -> () {
 // CHECK:         [[IS_ZERO:%[^,]+]] = icmp eq i64 [[REMAINING]], 0
 // CHECK:         br i1 [[IS_ZERO]], label %[[EXIT:[^,]+]], label %[[BACKEDGE:[^,]+]]
 // CHECK:       [[BACKEDGE]]:
-// CHECK:         call void @llvm.stackrestore(ptr [[STACK_BEFORE_SECOND_ALLOCA]])
-// CHECK:         call void @llvm.stackrestore(ptr [[STACK_BEFORE_FIRST_ALLOCA]])
+// CHECK:         call void @llvm.stackrestore.p0(ptr [[STACK_BEFORE_SECOND_ALLOCA]])
+// CHECK:         call void @llvm.stackrestore.p0(ptr [[STACK_BEFORE_FIRST_ALLOCA]])
 // CHECK:         br label %[[HEADER]]
 // CHECK:       [[EXIT]]:
-// CHECK:         call void @llvm.stackrestore(ptr [[STACK_BEFORE_SECOND_ALLOCA]])
-// CHECK:         call void @llvm.stackrestore(ptr [[STACK_BEFORE_FIRST_ALLOCA]])
+// CHECK:         [[STACK_BEFORE_SECOND_ALLOCAlcssa:%.*]] = phi ptr [ [[STACK_BEFORE_SECOND_ALLOCA]], %{{.*}} ]
+// CHECK:         [[STACK_BEFORE_FIRST_ALLOCAlcssa:%.*]] = phi ptr [ [[STACK_BEFORE_FIRST_ALLOCA]], %{{.*}} ]
+// CHECK:         call void @llvm.stackrestore.p0(ptr [[STACK_BEFORE_SECOND_ALLOCAlcssa]])
+// CHECK:         call void @llvm.stackrestore.p0(ptr [[STACK_BEFORE_FIRST_ALLOCAlcssa]])
 // CHECK:         ret void
 // CHECK:       }
 sil @looper : $@convention(thin) <each T_1, each T_2> () -> () {
diff --git a/validation-test/IRGen/rdar114013709.swift b/validation-test/IRGen/rdar114013709.swift
index 71b1549c0d508..dc04b86ad3eb0 100644
--- a/validation-test/IRGen/rdar114013709.swift
+++ b/validation-test/IRGen/rdar114013709.swift
@@ -1,6 +1,6 @@
 // RUN: %target-swift-frontend -O -primary-file %s -disable-availability-checking -emit-ir | %FileCheck %s
 
-// CHECK: define{{( dllexport)?}}{{( protected)?}} i32 @main{{.*}} {
+// CHECK: define{{( dllexport)?}}{{( protected)?}}{{( noundef)?}} i32 @main{{.*}} {
 // CHECK:      store ptr %{{[0-9]+}}, ptr @"$s13rdar1140137091xQrvp"
 actor Actor {}
 let x: some Actor = Actor()