diff --git a/clang-tools-extra/clang-tidy/modernize/UseEmplaceCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseEmplaceCheck.cpp
@@ -13,6 +13,10 @@ using namespace clang::ast_matchers;
 namespace clang::tidy::modernize {
 
 namespace {
+AST_MATCHER_P(InitListExpr, initCountLeq, unsigned, N) {
+  return Node.getNumInits() <= N;
+}
+
 // Identical to hasAnyName, except it does not take template specifiers into
 // account. This is used to match the functions names as in
 // DefaultEmplacyFunctions below without caring about the template types of the
@@ -205,11 +209,12 @@ void UseEmplaceCheck::registerMatchers(MatchFinder *Finder) {
   auto HasConstructExpr = has(ignoringImplicit(SoughtConstructExpr));
 
   // allow for T{} to be replaced, even if no CTOR is declared
-  auto HasConstructInitListExpr = has(initListExpr(anyOf(
-      allOf(has(SoughtConstructExpr),
-            has(cxxConstructExpr(argumentCountIs(0)))),
-      has(cxxBindTemporaryExpr(has(SoughtConstructExpr),
-                               has(cxxConstructExpr(argumentCountIs(0))))))));
+  auto HasConstructInitListExpr = has(initListExpr(
+      initCountLeq(1), anyOf(allOf(has(SoughtConstructExpr),
+                                   has(cxxConstructExpr(argumentCountIs(0)))),
+                             has(cxxBindTemporaryExpr(
+                                 has(SoughtConstructExpr),
+                                 has(cxxConstructExpr(argumentCountIs(0))))))));
   auto HasBracedInitListExpr =
       anyOf(has(cxxBindTemporaryExpr(HasConstructInitListExpr)),
             HasConstructInitListExpr);

diff --git a/clang-tools-extra/clang-tidy/readability/AvoidReturnWithVoidValueCheck.cpp b/clang-tools-extra/clang-tidy/readability/AvoidReturnWithVoidValueCheck.cpp
@@ -0,0 +1,57 @@
+//===--- AvoidReturnWithVoidValueCheck.cpp - clang-tidy -------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "AvoidReturnWithVoidValueCheck.h"
+#include "clang/AST/Stmt.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::readability {
+
+static constexpr auto IgnoreMacrosName = "IgnoreMacros";
+static constexpr auto IgnoreMacrosDefault = true;
+
+static constexpr auto StrictModeName = "StrictMode";
+static constexpr auto StrictModeDefault = true;
+
+AvoidReturnWithVoidValueCheck::AvoidReturnWithVoidValueCheck(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      IgnoreMacros(
+          Options.getLocalOrGlobal(IgnoreMacrosName, IgnoreMacrosDefault)),
+      StrictMode(Options.getLocalOrGlobal(StrictModeName, StrictModeDefault)) {}
+
+void AvoidReturnWithVoidValueCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      returnStmt(
+          hasReturnValue(allOf(hasType(voidType()), unless(initListExpr()))),
+          optionally(hasParent(compoundStmt().bind("compound_parent"))))
+          .bind("void_return"),
+      this);
+}
+
+void AvoidReturnWithVoidValueCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  const auto *VoidReturn = Result.Nodes.getNodeAs<ReturnStmt>("void_return");
+  if (IgnoreMacros && VoidReturn->getBeginLoc().isMacroID())
+    return;
+  if (!StrictMode && !Result.Nodes.getNodeAs<CompoundStmt>("compound_parent"))
+    return;
+  diag(VoidReturn->getBeginLoc(), "return statement within a void function "
+                                  "should not have a specified return value");
+}
+
+void AvoidReturnWithVoidValueCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, IgnoreMacrosName, IgnoreMacros);
+  Options.store(Opts, StrictModeName, StrictMode);
+}
+
+} // namespace clang::tidy::readability
diff --git a/clang-tools-extra/clang-tidy/readability/AvoidReturnWithVoidValueCheck.h b/clang-tools-extra/clang-tidy/readability/AvoidReturnWithVoidValueCheck.h
@@ -0,0 +1,44 @@
+//===--- AvoidReturnWithVoidValueCheck.h - clang-tidy -----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_AVOIDRETURNWITHVOIDVALUECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_AVOIDRETURNWITHVOIDVALUECHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang::tidy::readability {
+
+/// Finds return statements with `void` values used within functions with `void`
+/// result types.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/readability/avoid-return-with-void-value.html
+class AvoidReturnWithVoidValueCheck : public ClangTidyCheck {
+public:
+  AvoidReturnWithVoidValueCheck(StringRef Name, ClangTidyContext *Context);
+
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+  std::optional<TraversalKind> getCheckTraversalKind() const override {
+    return TK_IgnoreUnlessSpelledInSource;
+  }
+  bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
+    return LangOpts.CPlusPlus;
+  }
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
+
+private:
+  bool IgnoreMacros;
+  bool StrictMode;
+};
+
+} // namespace clang::tidy::readability
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_AVOIDRETURNWITHVOIDVALUECHECK_H
diff --git a/clang-tools-extra/clang-tidy/readability/CMakeLists.txt b/clang-tools-extra/clang-tidy/readability/CMakeLists.txt
@@ -5,6 +5,7 @@ set(LLVM_LINK_COMPONENTS
 
 add_clang_library(clangTidyReadabilityModule
   AvoidConstParamsInDecls.cpp
+  AvoidReturnWithVoidValueCheck.cpp
   AvoidUnconditionalPreprocessorIfCheck.cpp
   BracesAroundStatementsCheck.cpp
   ConstReturnTypeCheck.cpp

diff --git a/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp b/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp
@@ -10,6 +10,7 @@
 #include "../ClangTidyModule.h"
 #include "../ClangTidyModuleRegistry.h"
 #include "AvoidConstParamsInDecls.h"
+#include "AvoidReturnWithVoidValueCheck.h"
 #include "AvoidUnconditionalPreprocessorIfCheck.h"
 #include "BracesAroundStatementsCheck.h"
 #include "ConstReturnTypeCheck.h"
@@ -63,6 +64,8 @@ class ReadabilityModule : public ClangTidyModule {
   void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
     CheckFactories.registerCheck<AvoidConstParamsInDecls>(
         "readability-avoid-const-params-in-decls");
+    CheckFactories.registerCheck<AvoidReturnWithVoidValueCheck>(
+        "readability-avoid-return-with-void-value");
     CheckFactories.registerCheck<AvoidUnconditionalPreprocessorIfCheck>(
         "readability-avoid-unconditional-preprocessor-if");
     CheckFactories.registerCheck<BracesAroundStatementsCheck>(

diff --git a/clang-tools-extra/clangd/AST.cpp b/clang-tools-extra/clangd/AST.cpp
@@ -757,7 +757,7 @@ const TemplateTypeParmType *getFunctionPackType(const FunctionDecl *Callee) {
 // Returns the template parameter pack type that this parameter was expanded
 // from (if in the Args... or Args&... or Args&&... form), if this is the case,
 // nullptr otherwise.
-const TemplateTypeParmType *getUnderylingPackType(const ParmVarDecl *Param) {
+const TemplateTypeParmType *getUnderlyingPackType(const ParmVarDecl *Param) {
   const auto *PlainType = Param->getType().getTypePtr();
   if (auto *RT = dyn_cast<ReferenceType>(PlainType))
     PlainType = RT->getPointeeTypeAsWritten().getTypePtr();
@@ -793,8 +793,8 @@ class ForwardingCallVisitor
     : public RecursiveASTVisitor<ForwardingCallVisitor> {
 public:
   ForwardingCallVisitor(ArrayRef<const ParmVarDecl *> Parameters)
-      : Parameters{Parameters}, PackType{getUnderylingPackType(
-                                    Parameters.front())} {}
+      : Parameters{Parameters},
+        PackType{getUnderlyingPackType(Parameters.front())} {}
 
   bool VisitCallExpr(CallExpr *E) {
     auto *Callee = getCalleeDeclOrUniqueOverload(E);
@@ -859,7 +859,7 @@ class ForwardingCallVisitor
     if (const auto *TTPT = getFunctionPackType(Callee)) {
       // In this case: Separate the parameters into head, pack and tail
       auto IsExpandedPack = [&](const ParmVarDecl *P) {
-        return getUnderylingPackType(P) == TTPT;
+        return getUnderlyingPackType(P) == TTPT;
       };
       ForwardingInfo FI;
       FI.Head = MatchingParams.take_until(IsExpandedPack);
@@ -964,7 +964,7 @@ resolveForwardingParameters(const FunctionDecl *D, unsigned MaxDepth) {
   if (const auto *TTPT = getFunctionPackType(D)) {
     // Split the parameters into head, pack and tail
     auto IsExpandedPack = [TTPT](const ParmVarDecl *P) {
-      return getUnderylingPackType(P) == TTPT;
+      return getUnderlyingPackType(P) == TTPT;
     };
     ArrayRef<const ParmVarDecl *> Head = Parameters.take_until(IsExpandedPack);
     ArrayRef<const ParmVarDecl *> Pack =
@@ -1016,7 +1016,7 @@ resolveForwardingParameters(const FunctionDecl *D, unsigned MaxDepth) {
 }
 
 bool isExpandedFromParameterPack(const ParmVarDecl *D) {
-  return getUnderylingPackType(D) != nullptr;
+  return getUnderlyingPackType(D) != nullptr;
 }
 
 } // namespace clangd

diff --git a/clang-tools-extra/clangd/Selection.cpp b/clang-tools-extra/clangd/Selection.cpp
@@ -1113,6 +1113,9 @@ const DeclContext &SelectionTree::Node::getDeclContext() const {
           return *DC;
       return *Current->getLexicalDeclContext();
     }
+    if (const auto *LE = CurrentNode->ASTNode.get<LambdaExpr>())
+      if (CurrentNode != this)
+        return *LE->getCallOperator();
   }
   llvm_unreachable("A tree must always be rooted at TranslationUnitDecl.");
 }

diff --git a/clang-tools-extra/clangd/unittests/SelectionTests.cpp b/clang-tools-extra/clangd/unittests/SelectionTests.cpp
@@ -880,6 +880,19 @@ TEST(SelectionTest, DeclContextIsLexical) {
   }
 }
 
+TEST(SelectionTest, DeclContextLambda) {
+  llvm::Annotations Test(R"cpp(
+    void foo();
+    auto lambda = [] {
+      return $1^foo();
+    };
+  )cpp");
+  auto AST = TestTU::withCode(Test.code()).build();
+  auto ST = SelectionTree::createRight(AST.getASTContext(), AST.getTokens(),
+                                       Test.point("1"), Test.point("1"));
+  EXPECT_TRUE(ST.commonAncestor()->getDeclContext().isFunctionOrMethod());
+}
+
 } // namespace
 } // namespace clangd
 } // namespace clang
diff --git a/clang-tools-extra/clangd/unittests/tweaks/AddUsingTests.cpp b/clang-tools-extra/clangd/unittests/tweaks/AddUsingTests.cpp
@@ -309,6 +309,29 @@ namespace foo { void fun(); }
 void foo::fun() {
   ff();
 })cpp"},
+      // Inside a lambda.
+      {
+          R"cpp(
+namespace NS {
+void unrelated();
+void foo();
+}
+
+auto L = [] {
+  using NS::unrelated;
+  NS::f^oo();
+};)cpp",
+          R"cpp(
+namespace NS {
+void unrelated();
+void foo();
+}
+
+auto L = [] {
+  using NS::foo;using NS::unrelated;
+  foo();
+};)cpp",
+      },
       // If all other using are fully qualified, add ::
       {R"cpp(
 #include "test.hpp"

diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -230,6 +230,12 @@ New checks
   Detects C++ code where a reference variable is used to extend the lifetime
   of a temporary object that has just been constructed.
 
+- New :doc:`readability-avoid-return-with-void-value
+  <clang-tidy/checks/readability/avoid-return-with-void-value>` check.
+
+  Finds return statements with ``void`` values used within functions with
+  ``void`` result types.
+
 New check aliases
 ^^^^^^^^^^^^^^^^^
 
@@ -295,6 +301,10 @@ Changes in existing checks
   coroutine functions and increase issue detection for cases involving type
   aliases with references.
 
+- Improved :doc:`cppcoreguidelines-missing-std-forward
+  <clang-tidy/checks/cppcoreguidelines/missing-std-forward>` check to
+  address false positives in the capture list and body of lambdas.
+
 - Improved :doc:`cppcoreguidelines-narrowing-conversions
   <clang-tidy/checks/cppcoreguidelines/narrowing-conversions>` check by
   extending the `IgnoreConversionFromTypes` option to include types without a
@@ -358,7 +368,8 @@ Changes in existing checks
   <clang-tidy/checks/misc/const-correctness>` check to avoid false positive when
   using pointer to member function. Additionally, the check no longer emits
   a diagnostic when a variable that is not type-dependent is an operand of a
-  type-dependent binary operator.
+  type-dependent binary operator. Improved performance of the check through
+  optimizations.
 
 - Improved :doc:`misc-include-cleaner
   <clang-tidy/checks/misc/include-cleaner>` check by adding option
@@ -372,7 +383,7 @@ Changes in existing checks
 
 - Improved :doc:`misc-unused-using-decls
   <clang-tidy/checks/misc/unused-using-decls>` check to avoid false positive when
-  using in elaborated type.
+  using in elaborated type and only check cpp files.
 
 - Improved :doc:`modernize-avoid-bind
   <clang-tidy/checks/modernize/avoid-bind>` check to
@@ -394,6 +405,10 @@ Changes in existing checks
   false-positives when constructing the container with ``count`` copies of
   elements with value ``value``.
 
+- Improved :doc:`modernize-use-emplace
+  <clang-tidy/checks/modernize/use-emplace>` to not replace aggregates that
+  ``emplace`` cannot construct with aggregate initialization.
+
 - Improved :doc:`modernize-use-equals-delete
   <clang-tidy/checks/modernize/use-equals-delete>` check to ignore
   false-positives when special member function is actually used or implicit.

diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -337,6 +337,7 @@ Clang-Tidy Checks
    :doc:`portability-simd-intrinsics <portability/simd-intrinsics>`,
    :doc:`portability-std-allocator-const <portability/std-allocator-const>`,
    :doc:`readability-avoid-const-params-in-decls <readability/avoid-const-params-in-decls>`, "Yes"
+   :doc:`readability-avoid-return-with-void-value <readability/avoid-return-with-void-value>`,
    :doc:`readability-avoid-unconditional-preprocessor-if <readability/avoid-unconditional-preprocessor-if>`,
    :doc:`readability-braces-around-statements <readability/braces-around-statements>`, "Yes"
    :doc:`readability-const-return-type <readability/const-return-type>`, "Yes"

diff --git a/...tools-extra/docs/clang-tidy/checks/readability/avoid-return-with-void-value.rst b/...tools-extra/docs/clang-tidy/checks/readability/avoid-return-with-void-value.rst
@@ -0,0 +1,51 @@
+.. title:: clang-tidy - readability-avoid-return-with-void-value
+
+readability-avoid-return-with-void-value
+========================================
+
+Finds return statements with ``void`` values used within functions with
+``void`` result types.
+
+A function with a ``void`` return type is intended to perform a task without
+producing a return value. Return statements with expressions could lead
+to confusion and may miscommunicate the function's intended behavior.
+
+Example:
+
+.. code-block::
+
+   void g();
+   void f() {
+       // ...
+       return g();
+   }
+
+In a long function body, the ``return`` statement suggests that the function
+returns a value. However, ``return g();`` is a combination of two statements
+that should be written as
+
+.. code-block::
+
+   g();
+   return;
+
+to make clear that ``g()`` is called and immediately afterwards the function 
+returns (nothing).
+
+In C, the same issue is detected by the compiler if the ``-Wpedantic`` mode
+is enabled.
+
+Options
+-------
+
+.. option::  IgnoreMacros
+
+  The value `false` specifies that return statements expanded
+  from macros are not checked. The default value is `true`.
+
+.. option::  StrictMode
+
+  The value `false` specifies that a direct return statement shall
+  be excluded from the analysis if it is the only statement not 
+  contained in a block like ``if (cond) return g();``. The default
+  value is `true`.
diff --git a/clang-tools-extra/include-cleaner/tool/IncludeCleaner.cpp b/clang-tools-extra/include-cleaner/tool/IncludeCleaner.cpp
@@ -16,10 +16,10 @@
 #include "clang/Tooling/Tooling.h"
 #include "llvm/ADT/STLFunctionalExtras.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FormatVariadic.h"
-#include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Regex.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/raw_ostream.h"
@@ -110,14 +110,16 @@ format::FormatStyle getStyle(llvm::StringRef Filename) {
 
 class Action : public clang::ASTFrontendAction {
 public:
-  Action(llvm::function_ref<bool(llvm::StringRef)> HeaderFilter)
-      : HeaderFilter(HeaderFilter){};
+  Action(llvm::function_ref<bool(llvm::StringRef)> HeaderFilter,
+         llvm::StringMap<std::string> &EditedFiles)
+      : HeaderFilter(HeaderFilter), EditedFiles(EditedFiles) {}
 
 private:
   RecordedAST AST;
   RecordedPP PP;
   PragmaIncludes PI;
   llvm::function_ref<bool(llvm::StringRef)> HeaderFilter;
+  llvm::StringMap<std::string> &EditedFiles;
 
   bool BeginInvocation(CompilerInstance &CI) override {
     // We only perform include-cleaner analysis. So we disable diagnostics that
@@ -181,17 +183,8 @@ class Action : public clang::ASTFrontendAction {
       }
     }
 
-    if (Edit && (!Results.Missing.empty() || !Results.Unused.empty())) {
-      if (auto Err = llvm::writeToOutput(
-              Path, [&](llvm::raw_ostream &OS) -> llvm::Error {
-                OS << Final;
-                return llvm::Error::success();
-              })) {
-        llvm::errs() << "Failed to apply edits to " << Path << ": "
-                     << toString(std::move(Err)) << "\n";
-        ++Errors;
-      }
-    }
+    if (!Results.Missing.empty() || !Results.Unused.empty())
+      EditedFiles.try_emplace(Path, Final);
   }
 
   void writeHTML() {
@@ -215,11 +208,17 @@ class ActionFactory : public tooling::FrontendActionFactory {
       : HeaderFilter(HeaderFilter) {}
 
   std::unique_ptr<clang::FrontendAction> create() override {
-    return std::make_unique<Action>(HeaderFilter);
+    return std::make_unique<Action>(HeaderFilter, EditedFiles);
+  }
+
+  const llvm::StringMap<std::string> &editedFiles() const {
+    return EditedFiles;
   }
 
 private:
   llvm::function_ref<bool(llvm::StringRef)> HeaderFilter;
+  // Map from file name to final code with the include edits applied.
+  llvm::StringMap<std::string> EditedFiles;
 };
 
 std::function<bool(llvm::StringRef)> headerFilter() {
@@ -274,21 +273,26 @@ int main(int argc, const char **argv) {
 
   clang::tooling::ClangTool Tool(OptionsParser->getCompilations(),
                                  OptionsParser->getSourcePathList());
-  std::vector<std::unique_ptr<llvm::MemoryBuffer>> Buffers;
-  for (const auto &File : OptionsParser->getSourcePathList()) {
-    auto Content = llvm::MemoryBuffer::getFile(File);
-    if (!Content) {
-      llvm::errs() << "Error: can't read file '" << File
-                   << "': " << Content.getError().message() << "\n";
-      return 1;
-    }
-    Buffers.push_back(std::move(Content.get()));
-    Tool.mapVirtualFile(File, Buffers.back()->getBuffer());
-  }
 
   auto HeaderFilter = headerFilter();
   if (!HeaderFilter)
     return 1; // error already reported.
   ActionFactory Factory(HeaderFilter);
-  return Tool.run(&Factory) || Errors != 0;
+  auto ErrorCode = Tool.run(&Factory);
+  if (Edit) {
+    for (const auto &NameAndContent : Factory.editedFiles()) {
+      llvm::StringRef FileName = NameAndContent.first();
+      const std::string &FinalCode = NameAndContent.second;
+      if (auto Err = llvm::writeToOutput(
+              FileName, [&](llvm::raw_ostream &OS) -> llvm::Error {
+                OS << FinalCode;
+                return llvm::Error::success();
+              })) {
+        llvm::errs() << "Failed to apply edits to " << FileName << ": "
+                     << toString(std::move(Err)) << "\n";
+        ++Errors;
+      }
+    }
+  }
+  return ErrorCode || Errors != 0;
 }
diff --git a/clang-tools-extra/test/clang-doc/templates.cpp b/clang-tools-extra/test/clang-doc/templates.cpp
@@ -7,7 +7,7 @@
 // RUN: rm -rf %t
 
 template<typename T, int U = 1>
-void function<bool, 0>(T x) {}
+void function(T x) {}
 
 template<>
 void function<bool, 0>(bool x) {}

diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/missing-std-forward.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/missing-std-forward.cpp
@@ -90,9 +90,9 @@ void lambda_value_capture(T&& t) {
 }
 
 template <class T>
-void lambda_value_reference(T&& t) {
-  // CHECK-MESSAGES: :[[@LINE-1]]:33: warning: forwarding reference parameter 't' is never forwarded inside the function body [cppcoreguidelines-missing-std-forward]
-  [&]() { T other = std::forward<T>(t); };
+void lambda_value_capture_copy(T&& t) {
+  // CHECK-MESSAGES: :[[@LINE-1]]:36: warning: forwarding reference parameter 't' is never forwarded inside the function body [cppcoreguidelines-missing-std-forward]
+  [&,t]() { T other = std::forward<T>(t); };
 }
 
 } // namespace positive_cases
@@ -147,4 +147,29 @@ class AClass {
   T data;
 };
 
+template <class T>
+void lambda_value_reference(T&& t) {
+  [&]() { T other = std::forward<T>(t); };
+}
+
+template<typename T>
+void lambda_value_reference_capture_list_ref_1(T&& t) {
+    [=, &t] { T other = std::forward<T>(t); };
+}
+
+template<typename T>
+void lambda_value_reference_capture_list_ref_2(T&& t) {
+    [&t] { T other = std::forward<T>(t); };
+}
+
+template<typename T>
+void lambda_value_reference_capture_list(T&& t) {
+    [t = std::forward<T>(t)] { t(); };
+}
+
+template <class T>
+void lambda_value_reference_auxiliary_var(T&& t) {
+  [&x = t]() { T other = std::forward<T>(x); };
+}
+
 } // namespace negative_cases
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-emplace.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-emplace.cpp
@@ -1183,6 +1183,11 @@ struct NonTrivialWithVector {
   std::vector<int> it;
 };
 
+struct NonTrivialWithIntAndVector {
+  int x;
+  std::vector<int> it;
+};
+
 struct NonTrivialWithCtor {
   NonTrivialWithCtor();
   NonTrivialWithCtor(std::vector<int> const&);
@@ -1332,6 +1337,14 @@ void testBracedInitTemporaries() {
   v3.push_back(NonTrivialWithCtor{{}});
   v3.push_back({{0}});
   v3.push_back({{}});
+
+  std::vector<NonTrivialWithIntAndVector> v4;
+
+  // These should not be noticed or fixed; after the correction, the code won't
+  // compile.
+  v4.push_back(NonTrivialWithIntAndVector{1, {}});
+  v4.push_back(NonTrivialWithIntAndVector{});
+  v4.push_back({});
 }
 
 void testWithPointerTypes() {

diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/avoid-return-with-void-value.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/avoid-return-with-void-value.cpp
@@ -0,0 +1,69 @@
+// RUN: %check_clang_tidy %s readability-avoid-return-with-void-value %t
+// RUN: %check_clang_tidy -check-suffixes=,INCLUDE-MACROS %s readability-avoid-return-with-void-value %t \
+// RUN:     -- -config="{CheckOptions: [{key: readability-avoid-return-with-void-value.IgnoreMacros, value: false}]}" \
+// RUN:     --
+// RUN: %check_clang_tidy -check-suffixes=LENIENT %s readability-avoid-return-with-void-value %t \
+// RUN:     -- -config="{CheckOptions: [{key: readability-avoid-return-with-void-value.StrictMode, value: false}]}" \
+// RUN:     --
+
+void f1();
+
+void f2() {
+    return f1();
+    // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+    // CHECK-MESSAGES-LENIENT: :[[@LINE-2]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+}
+
+void f3(bool b) {
+    if (b) return f1();
+    // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+    return f2();
+    // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+    // CHECK-MESSAGES-LENIENT: :[[@LINE-2]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+}
+
+template<class T>
+T f4() {}
+
+void f5() {
+    return f4<void>();
+    // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+    // CHECK-MESSAGES-LENIENT: :[[@LINE-2]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+}
+
+void f6() { return; }
+
+int f7() { return 1; }
+
+int f8() { return f7(); }
+
+void f9() {
+    return (void)f7();
+    // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+    // CHECK-MESSAGES-LENIENT: :[[@LINE-2]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+}
+
+#define RETURN_VOID return (void)1
+
+void f10() {
+    RETURN_VOID;
+    // CHECK-MESSAGES-INCLUDE-MACROS: :[[@LINE-1]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+}
+
+template <typename A> 
+struct C {
+  C(A) {}
+};
+
+template <class T> 
+C<T> f11() { return {}; }
+
+using VOID = void;
+
+VOID f12();
+
+VOID f13() {
+    return f12();
+    // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+    // CHECK-MESSAGES-LENIENT: :[[@LINE-2]]:5: warning: return statement within a void function should not have a specified return value [readability-avoid-return-with-void-value]
+}
diff --git a/clang/.clang-tidy b/clang/.clang-tidy
@@ -1,5 +1,5 @@
 # Note that the readability-identifier-naming check is disabled, there are too
 # many violations in the codebase and they create too much noise in clang-tidy
 # results.
-Checks: '-readability-identifier-naming'
+Checks: '-readability-identifier-naming, -misc-include*'
 InheritParentConfig: true
diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
@@ -193,6 +193,12 @@ set(C_INCLUDE_DIRS "" CACHE STRING
 set(GCC_INSTALL_PREFIX "" CACHE PATH "Directory where gcc is installed." )
 set(DEFAULT_SYSROOT "" CACHE STRING
   "Default <path> to all compiler invocations for --sysroot=<path>." )
+if(GCC_INSTALL_PREFIX)
+  message(WARNING "GCC_INSTALL_PREFIX is deprecated and will be removed. Use "
+    "configuration files (https://clang.llvm.org/docs/UsersManual.html#configuration-files)"
+    "to specify the default --gcc-install-dir= or --gcc-triple=. --gcc-toolchain= is discouraged. "
+    "See https://github.com/llvm/llvm-project/pull/77537 for detail.")
+endif()
 
 set(ENABLE_LINKER_BUILD_ID OFF CACHE BOOL "pass --build-id to ld")
 

diff --git a/clang/cmake/caches/Release.cmake b/clang/cmake/caches/Release.cmake
@@ -0,0 +1,41 @@
+# Plain options configure the first build.
+# BOOTSTRAP_* options configure the second build.
+# BOOTSTRAP_BOOTSTRAP_* options configure the third build.
+
+set(CMAKE_BUILD_TYPE RELEASE CACHE STRING "")
+
+# Stage 1 Bootstrap Setup
+set(CLANG_ENABLE_BOOTSTRAP ON CACHE BOOL "")
+set(CLANG_BOOTSTRAP_TARGETS
+  clang
+  check-all
+  check-llvm
+  check-clang
+  test-suite
+  stage3
+  stage3-clang
+  stage3-check-all
+  stage3-check-llvm
+  stage3-check-clang
+  stage3-install
+  stage3-test-suite CACHE STRING "")
+
+# Stage 1 Options
+set(LLVM_ENABLE_PROJECTS "clang" CACHE STRING "")
+set(LLVM_TARGETS_TO_BUILD Native CACHE STRING "")
+
+# Stage 2 Bootstrap Setup
+set(BOOTSTRAP_CLANG_ENABLE_BOOTSTRAP ON CACHE STRING "")
+set(BOOTSTRAP_CLANG_BOOTSTRAP_TARGETS
+  clang
+  check-all
+  check-llvm
+  check-clang CACHE STRING "")
+
+# Stage 2 Options
+set(BOOTSTRAP_LLVM_ENABLE_PROJECTS "clang" CACHE STRING "")
+set(BOOTSTRAP_LLVM_TARGETS_TO_BUILD Native CACHE STRING "")
+
+# Stage 3 Options
+set(BOOTSTRAP_BOOTSTRAP_LLVM_ENABLE_RUNTIMES "compiler-rt;libcxx;libcxxabi;libunwind" CACHE STRING "")
+set(BOOTSTRAP_BOOTSTRAP_LLVM_ENABLE_PROJECTS "clang;lld;lldb;clang-tools-extra;bolt;polly;mlir;flang" CACHE STRING "")
diff --git a/clang/docs/ClangFormat.rst b/clang/docs/ClangFormat.rst
@@ -131,6 +131,9 @@ An easy way to create the ``.clang-format`` file is:
 
 Available style options are described in :doc:`ClangFormatStyleOptions`.
 
+.clang-format-ignore
+====================
+
 You can create ``.clang-format-ignore`` files to make ``clang-format`` ignore
 certain files. A ``.clang-format-ignore`` file consists of patterns of file path
 names. It has the following format:
@@ -141,7 +144,8 @@ names. It has the following format:
 * A non-comment line is a single pattern.
 * The slash (``/``) is used as the directory separator.
 * A pattern is relative to the directory of the ``.clang-format-ignore`` file
-  (or the root directory if the pattern starts with a slash).
+  (or the root directory if the pattern starts with a slash). Patterns
+  containing drive names (e.g. ``C:``) are not supported.
 * Patterns follow the rules specified in `POSIX 2.13.1, 2.13.2, and Rule 1 of
   2.13.3 <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/
   V3_chap02.html#tag_18_13>`_.

diff --git a/clang/docs/ClangFormatStyleOptions.rst b/clang/docs/ClangFormatStyleOptions.rst
@@ -392,6 +392,23 @@ the configuration (without a prefix: ``Auto``).
       a &= 2;
       bbb = 2;
 
+  * ``bool AlignFunctionPointers`` Only for ``AlignConsecutiveDeclarations``. Whether function pointers are
+    aligned.
+
+    .. code-block:: c++
+
+      true:
+      unsigned i;
+      int     &r;
+      int     *p;
+      int      (*f)();
+
+      false:
+      unsigned i;
+      int     &r;
+      int     *p;
+      int (*f)();
+
   * ``bool PadOperators`` Only for ``AlignConsecutiveAssignments``.  Whether short assignment
     operators are left-padded to the same length as long ones in order to
     put all assignment operators to the right of the left hand side.
@@ -517,6 +534,23 @@ the configuration (without a prefix: ``Auto``).
       a &= 2;
       bbb = 2;
 
+  * ``bool AlignFunctionPointers`` Only for ``AlignConsecutiveDeclarations``. Whether function pointers are
+    aligned.
+
+    .. code-block:: c++
+
+      true:
+      unsigned i;
+      int     &r;
+      int     *p;
+      int      (*f)();
+
+      false:
+      unsigned i;
+      int     &r;
+      int     *p;
+      int (*f)();
+
   * ``bool PadOperators`` Only for ``AlignConsecutiveAssignments``.  Whether short assignment
     operators are left-padded to the same length as long ones in order to
     put all assignment operators to the right of the left hand side.
@@ -642,6 +676,23 @@ the configuration (without a prefix: ``Auto``).
       a &= 2;
       bbb = 2;
 
+  * ``bool AlignFunctionPointers`` Only for ``AlignConsecutiveDeclarations``. Whether function pointers are
+    aligned.
+
+    .. code-block:: c++
+
+      true:
+      unsigned i;
+      int     &r;
+      int     *p;
+      int      (*f)();
+
+      false:
+      unsigned i;
+      int     &r;
+      int     *p;
+      int (*f)();
+
   * ``bool PadOperators`` Only for ``AlignConsecutiveAssignments``.  Whether short assignment
     operators are left-padded to the same length as long ones in order to
     put all assignment operators to the right of the left hand side.
@@ -768,6 +819,23 @@ the configuration (without a prefix: ``Auto``).
       a &= 2;
       bbb = 2;
 
+  * ``bool AlignFunctionPointers`` Only for ``AlignConsecutiveDeclarations``. Whether function pointers are
+    aligned.
+
+    .. code-block:: c++
+
+      true:
+      unsigned i;
+      int     &r;
+      int     *p;
+      int      (*f)();
+
+      false:
+      unsigned i;
+      int     &r;
+      int     *p;
+      int (*f)();
+
   * ``bool PadOperators`` Only for ``AlignConsecutiveAssignments``.  Whether short assignment
     operators are left-padded to the same length as long ones in order to
     put all assignment operators to the right of the left hand side.

diff --git a/clang/docs/HLSL/FunctionCalls.rst b/clang/docs/HLSL/FunctionCalls.rst
@@ -0,0 +1,321 @@
+===================
+HLSL Function Calls
+===================
+
+.. contents::
+   :local:
+
+Introduction
+============
+
+This document describes the design and implementation of HLSL's function call
+semantics in Clang. This includes details related to argument conversion and
+parameter lifetimes.
+
+This document does not seek to serve as official documentation for HLSL's
+call semantics, but does provide an overview to assist a reader. The
+authoritative documentation for HLSL's language semantics is the `draft language
+specification <https://microsoft.github.io/hlsl-specs/specs/hlsl.pdf>`_.
+
+Argument Semantics
+==================
+
+In HLSL, all function arguments are passed by value in and out of functions.
+HLSL has 3 keywords which denote the parameter semantics (``in``, ``out`` and
+``inout``). In a function declaration a parameter may be annotated any of the
+following ways:
+
+#. <no parameter annotation> - denotes input
+#. ``in`` - denotes input
+#. ``out`` - denotes output
+#. ``in out`` - denotes input and output
+#. ``out in`` - denotes input and output
+#. ``inout`` - denotes input and output
+
+Parameters that are exclusively input behave like C/C++ parameters that are
+passed by value.
+
+For parameters that are output (or input and output), a temporary value is
+created in the caller. The temporary value is then passed by-address. For
+output-only parameters, the temporary is uninitialized when passed (if the
+parameter is not explicitly initialized inside the function an undefined value
+is stored back to the argument expression). For parameters that are both input
+and output, the temporary is initialized from the lvalue argument expression
+through implicit  or explicit casting from the lvalue argument type to the
+parameter type.
+
+On return of the function, the values of any parameter temporaries are written
+back to the argument expression through an inverted conversion sequence (if an
+``out`` parameter was not initialized in the function, the uninitialized value
+may be written back).
+
+Parameters of constant-sized array type are also passed with value semantics.
+This requires input parameters of arrays to construct temporaries and the
+temporaries go through array-to-pointer decay when initializing parameters.
+
+Implementations are allowed to avoid unnecessary temporaries, and HLSL's strict
+no-alias rules can enable some trivial optimizations.
+
+Array Temporaries
+-----------------
+
+Given the following example:
+
+.. code-block:: c++
+
+  void fn(float a[4]) {
+    a[0] = a[1] + a[2] + a[3];
+  }
+
+  float4 main() : SV_Target {
+    float arr[4] = {1, 1, 1, 1};
+    fn(arr);
+    return float4(arr[0], arr[1], arr[2], arr[3]);
+  }
+
+In C or C++, the array parameter decays to a pointer, so after the call to
+``fn``, the value of ``arr[0]`` is ``3``. In HLSL, the array is passed by value,
+so modifications inside ``fn`` do not propagate out.
+
+.. note::
+
+  DXC may pass unsized arrays directly as decayed pointers, which is an
+  unfortunate behavior divergence.
+
+Out Parameter Temporaries
+-------------------------
+
+.. code-block:: c++
+
+  void Init(inout int X, inout int Y) {
+    Y = 2;
+    X = 1;
+  }
+
+  void main() {
+    int V;
+    Init(V, V); // MSVC (or clang-cl) V == 2, Clang V == 1
+  }
+
+In the above example the ``Init`` function's behavior depends on the C++
+implementation. C++ does not define the order in which parameters are
+initialized or destroyed. In MSVC and Clang's MSVC compatibility mode, arguments
+are emitted right-to-left and destroyed left-to-right. This means that  the
+parameter initialization and destruction occurs in the order: {``Y``, ``X``,
+``~X``, ``~Y``}. This causes the write-back of the value of ``Y`` to occur last,
+so the resulting value of ``V`` is ``2``. In the Itanium C++ ABI, the  parameter
+ordering is reversed, so the initialization and destruction occurs in the order:
+{``X``, ``Y``, ``~Y``, ``X``}. This causes the write-back of the value ``X`` to
+occur last, resulting in the value of ``V`` being set to ``1``.
+
+.. code-block:: c++
+
+  void Trunc(inout int3 V) { }
+
+
+  void main() {
+    float3 F = {1.5, 2.6, 3.3};
+    Trunc(F); // F == {1.0, 2.0, 3.0}
+  }
+
+In the above example, the argument expression ``F`` undergoes element-wise
+conversion from a float vector to an integer vector to create a temporary
+``int3``. On expiration the temporary undergoes elementwise conversion back to
+the floating point vector type ``float3``. This results in an implicit
+element-wise conversion of the vector even if the value is unused in the
+function (effectively truncating the floating point values).
+
+
+.. code-block:: c++
+
+  void UB(out int X) {}
+
+  void main() {
+    int X = 7;
+    UB(X); // X is undefined!
+  }
+
+In this example an initialized value is passed to an ``out`` parameter.
+Parameters marked ``out`` are not initialized by the argument expression or
+implicitly by the function. They must be explicitly initialized. In this case
+the argument is not initialized in the function so the temporary is still
+uninitialized when it is copied back to the argument expression. This is
+undefined behavior in HLSL, and any use of the argument after the call is a use
+of an undefined value which may be illegal in the target (DXIL programs with
+used or potentially used ``undef`` or ``poison`` values fail validation).
+
+Clang Implementation
+====================
+
+.. note::
+
+  The implementation described here is a proposal. It has not yet been fully
+  implemented, so the current state of Clang's sources may not reflect this
+  design. A prototype implementation was built on DXC which is Clang-3.7 based.
+  The prototype can be found
+  `here <https://github.com/microsoft/DirectXShaderCompiler/pull/5249>`_. A lot
+  of the changes in the prototype implementation are restoring Clang-3.7 code
+  that was previously modified to its original state.
+
+The implementation in clang depends on two new AST nodes and minor extensions to
+Clang's existing support for Objective-C write-back arguments. The goal of this
+design is to capture the semantic details of HLSL function calls in the AST, and
+minimize the amount of magic that needs to occur during IR generation.
+
+The two new AST nodes are ``HLSLArrayTemporaryExpr`` and ``HLSLOutParamExpr``,
+which respectively represent the temporaries used for passing arrays by value
+and the temporaries created for function outputs.
+
+Array Temporaries
+-----------------
+
+The ``HLSLArrayTemporaryExpr`` represents temporary values for input
+constant-sized array arguments. This applies for all constant-sized array
+arguments regardless of whether or not the parameter is constant-sized or
+unsized.
+
+.. code-block:: c++
+
+  void SizedArray(float a[4]);
+  void UnsizedArray(float a[]);
+
+  void main() {
+    float arr[4] = {1, 1, 1, 1};
+    SizedArray(arr);
+    UnsizedArray(arr);
+  }
+
+In the example above, the following AST is generated for the call to
+``SizedArray``:
+
+.. code-block:: text
+
+  CallExpr 'void'
+  |-ImplicitCastExpr 'void (*)(float [4])' <FunctionToPointerDecay>
+  | `-DeclRefExpr 'void (float [4])' lvalue Function 'SizedArray' 'void (float [4])'
+  `-HLSLArrayTemporaryExpr 'float [4]'
+    `-DeclRefExpr 'float [4]' lvalue Var 'arr' 'float [4]'
+
+In the example above, the following AST is generated for the call to
+``UnsizedArray``:
+
+.. code-block:: text
+
+  CallExpr 'void'
+  |-ImplicitCastExpr 'void (*)(float [])' <FunctionToPointerDecay>
+  | `-DeclRefExpr 'void (float [])' lvalue Function 'UnsizedArray' 'void (float [])'
+  `-HLSLArrayTemporaryExpr 'float [4]'
+    `-DeclRefExpr 'float [4]' lvalue Var 'arr' 'float [4]'
+
+In both of these cases the argument expression is of known array size so we can
+initialize an appropriately sized temporary.
+
+It is illegal in HLSL to convert an unsized array to a sized array:
+
+.. code-block:: c++
+
+  void SizedArray(float a[4]);
+  void UnsizedArray(float a[]) {
+    SizedArray(a); // Cannot convert float[] to float[4]
+  }
+
+When converting a sized array to an unsized array, an array temporary can also
+be inserted. Given the following code:
+
+.. code-block:: c++
+
+  void UnsizedArray(float a[]);
+  void SizedArray(float a[4]) {
+    UnsizedArray(a);
+  }
+
+An expected AST should be something like:
+
+.. code-block:: text
+
+  CallExpr 'void'
+  |-ImplicitCastExpr 'void (*)(float [])' <FunctionToPointerDecay>
+  | `-DeclRefExpr 'void (float [])' lvalue Function 'UnsizedArray' 'void (float [])'
+  `-HLSLArrayTemporaryExpr 'float [4]'
+    `-DeclRefExpr 'float [4]' lvalue Var 'arr' 'float [4]'
+
+Out Parameter Temporaries
+-------------------------
+
+Output parameters are defined in HLSL as *casting expiring values* (cx-values),
+which is a term made up for HLSL. A cx-value is a temporary value which may be
+the result of a cast, and stores its value back to an lvalue when the value
+expires.
+
+To represent this concept in Clang we introduce a new ``HLSLOutParamExpr``. An
+``HLSLOutParamExpr`` has two forms, one with a single sub-expression and one
+with two sub-expressions.
+
+The single sub-expression form is used when the argument expression and the
+function parameter are the same type, so no cast is required. As in this
+example:
+
+.. code-block:: c++
+
+  void Init(inout int X) {
+    X = 1;
+  }
+
+  void main() {
+    int V;
+    Init(V);
+  }
+
+The expected AST formulation for this code would be something like:
+
+.. code-block:: text
+
+  CallExpr 'void'
+  |-ImplicitCastExpr 'void (*)(int &)' <FunctionToPointerDecay>
+  | `-DeclRefExpr 'void (int &)' lvalue Function  'Init' 'void (int &)'
+  |-HLSLOutParamExpr 'int' lvalue inout
+    `-DeclRefExpr 'int' lvalue Var 'V' 'int'
+
+The ``HLSLOutParamExpr`` captures that the value is ``inout`` vs ``out`` to
+denote whether or not the temporary is initialized from the sub-expression. If
+no casting is required the sub-expression denotes the lvalue expression that the
+cx-value will be copied to when the value expires.
+
+The two sub-expression form of the AST node is required when the argument type
+is not the same as the parameter type. Given this example:
+
+.. code-block:: c++
+
+  void Trunc(inout int3 V) { }
+
+
+  void main() {
+    float3 F = {1.5, 2.6, 3.3};
+    Trunc(F);
+  }
+
+For this case the ``HLSLOutParamExpr`` will have sub-expressions to record both
+casting expression sequences for the initialization and write back:
+
+.. code-block:: text
+
+  -CallExpr 'void'
+    |-ImplicitCastExpr 'void (*)(int3 &)' <FunctionToPointerDecay>
+    | `-DeclRefExpr 'void (int3 &)' lvalue Function 'inc_i32' 'void (int3 &)'
+    `-HLSLOutParamExpr 'int3' lvalue inout
+      |-ImplicitCastExpr 'float3' <IntegralToFloating>
+      | `-ImplicitCastExpr 'int3' <LValueToRValue>
+      |   `-OpaqueValueExpr 'int3' lvalue
+      `-ImplicitCastExpr 'int3' <FloatingToIntegral>
+        `-ImplicitCastExpr 'float3' <LValueToRValue>
+          `-DeclRefExpr 'float3' lvalue 'F' 'float3'
+
+In this formation the write-back casts are captured as the first sub-expression
+and they cast from an ``OpaqueValueExpr``. In IR generation we can use the
+``OpaqueValueExpr`` as a placeholder for the ``HLSLOutParamExpr``'s temporary
+value on function return.
+
+In code generation this can be implemented with some targeted extensions to the
+Objective-C write-back support. Specifically extending CGCall.cpp's
+``EmitWriteback`` function to support casting expressions and emission of
+aggregate lvalues.
diff --git a/clang/docs/HLSL/HLSLDocs.rst b/clang/docs/HLSL/HLSLDocs.rst
@@ -14,3 +14,4 @@ HLSL Design and Implementation
    HLSLIRReference
    ResourceTypes
    EntryFunctions
+   FunctionCalls
diff --git a/clang/docs/InternalsManual.rst b/clang/docs/InternalsManual.rst
@@ -931,7 +931,7 @@ the option appears on the command line, the argument value is simply copied.
 .. code-block:: text
 
   def isysroot : JoinedOrSeparate<["-"], "isysroot">,
-    Visibility<[ClangOption, CC1Option]>,
+    Visibility<[ClangOption, CC1Option, FlangOption]>,
     MarshallingInfoString<HeaderSearchOpts<"Sysroot">, [{"/"}]>;
 
 **List of Strings**
@@ -3364,7 +3364,7 @@ Multiple occurrences accumulate prefixes.  For example,
 
 Specifying Diagnostics
 ^^^^^^^^^^^^^^^^^^^^^^
-Indicating that a line expects an error or a warning is simple. Put a comment
+Indicating that a line expects an error or a warning is easy. Put a comment
 on the line that has the diagnostic, use
 ``expected-{error,warning,remark,note}`` to tag if it's an expected error,
 warning, remark, or note (respectively), and place the expected text between
@@ -3373,6 +3373,9 @@ enough to ensure that the correct diagnostic was emitted. (Note: full text
 should be included in test cases unless there is a compelling reason to use
 truncated text instead.)
 
+For a full description of the matching behavior, including more complex
+matching scenarios, see :ref:`matching <DiagnosticMatching>` below.
+
 Here's an example of the most commonly used way to specify expected
 diagnostics:
 
@@ -3458,8 +3461,33 @@ A range can also be specified by ``<n>-<m>``. For example:
 
 In this example, the diagnostic may appear only once, if at all.
 
+.. _DiagnosticMatching:
+
+Matching Modes
+~~~~~~~~~~~~~~
+
+The default matching mode is simple string, which looks for the expected text
+that appears between the first `{{` and `}}` pair of the comment. The string is
+interpreted just as-is, with one exception: the sequence `\n` is converted to a
+single newline character. This mode matches the emitted diagnostic when the
+text appears as a substring at any position of the emitted message.
+
+To enable matching against desired strings that contain `}}` or `{{`, the
+string-mode parser accepts opening delimiters of more than two curly braces,
+like `{{{`. It then looks for a closing delimiter of equal "width" (i.e `}}}`).
+For example:
+
+.. code-block:: c++
+
+  // expected-note {{{evaluates to '{{2, 3, 4}} == {0, 3, 4}'}}}
+
+The intent is to allow the delimeter to be wider than the longest `{` or `}`
+brace sequence in the content, so that if your expected text contains `{{{`
+(three braces) it may be delimited with `{{{{` (four braces), and so on.
+
 Regex matching mode may be selected by appending ``-re`` to the diagnostic type
-and including regexes wrapped in double curly braces in the directive, such as:
+and including regexes wrapped in double curly braces (`{{` and `}}`) in the
+directive, such as:
 
 .. code-block:: text
 
@@ -3471,6 +3499,8 @@ Examples matching error: "variable has incomplete type 'struct s'"
 
   // expected-error {{variable has incomplete type 'struct s'}}
   // expected-error {{variable has incomplete type}}
+  // expected-error {{{variable has incomplete type}}}
+  // expected-error {{{{variable has incomplete type}}}}
 
   // expected-error-re {{variable has type 'struct {{.}}'}}
   // expected-error-re {{variable has type 'struct {{.*}}'}}

diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
@@ -829,6 +829,7 @@ to ``float``; see below for more information on this emulation.
   see below.
 
 * ``_Float16`` is supported on the following targets:
+
   * 32-bit ARM (natively on some architecture versions)
   * 64-bit ARM (AArch64) (natively on ARMv8.2a and above)
   * AMDGPU (natively)
@@ -837,6 +838,7 @@ to ``float``; see below for more information on this emulation.
   * RISC-V (natively if Zfh or Zhinx is available)
 
 * ``__bf16`` is supported on the following targets (currently never natively):
+
   * 32-bit ARM
   * 64-bit ARM (AArch64)
   * RISC-V

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
@@ -37,6 +37,12 @@ These changes are ones which we think may surprise users when upgrading to
 Clang |release| because of the opportunity they pose for disruption to existing
 code bases.
 
+- The CMake variable ``GCC_INSTALL_PREFIX`` (which sets the default
+  ``--gcc-toolchain=``) is deprecated and will be removed. Specify
+  ``--gcc-install-dir=`` or ``--gcc-triple=`` in a `configuration file
+  <https://clang.llvm.org/docs/UsersManual.html#configuration-files>` as a
+  replacement.
+  (`#77537 <https://github.com/llvm/llvm-project/pull/77537>`_)
 
 C/C++ Language Potentially Breaking Changes
 -------------------------------------------
@@ -202,6 +208,11 @@ C Language Changes
 - Enums will now be represented in TBAA metadata using their actual underlying
   integer type. Previously they were treated as chars, which meant they could
   alias with all other types.
+- Clang now supports the C-only attribute ``counted_by``. When applied to a
+  struct's flexible array member, it points to the struct field that holds the
+  number of elements in the flexible array member. This information can improve
+  the results of the array bound sanitizer and the
+  ``__builtin_dynamic_object_size`` builtin.
 
 C23 Feature Support
 ^^^^^^^^^^^^^^^^^^^
@@ -357,6 +368,7 @@ Attribute Changes in Clang
 - Clang now introduced ``[[clang::coro_lifetimebound]]`` attribute.
   All parameters of a function are considered to be lifetime bound if the function
   returns a type annotated with ``[[clang::coro_lifetimebound]]`` and ``[[clang::coro_return_type]]``.
+  This analysis can be disabled for a function by annotating the function with ``[[clang::coro_disable_lifetimebound]]``.
 
 Improvements to Clang's diagnostics
 -----------------------------------
@@ -518,6 +530,9 @@ Improvements to Clang's diagnostics
 - Clang now diagnoses definitions of friend function specializations, e.g. ``friend void f<>(int) {}``.
 - Clang now diagnoses narrowing conversions involving const references.
   (`#63151: <https://github.com/llvm/llvm-project/issues/63151>`_).
+- Clang now diagnoses unexpanded packs within the template argument lists of function template specializations.
+- Clang now diagnoses attempts to bind a bitfield to an NTTP of a reference type as erroneous
+  converted constant expression and not as a reference to subobject.
 
 
 Improvements to Clang's time-trace
@@ -607,7 +622,9 @@ Bug Fixes in This Version
 - Clang will correctly evaluate ``noexcept`` expression for template functions
   of template classes. Fixes
   (`#68543 <https://github.com/llvm/llvm-project/issues/68543>`_,
-  `#42496 <https://github.com/llvm/llvm-project/issues/42496>`_)
+  `#42496 <https://github.com/llvm/llvm-project/issues/42496>`_,
+  `#77071 <https://github.com/llvm/llvm-project/issues/77071>`_,
+  `#77411 <https://github.com/llvm/llvm-project/issues/77411>`_)
 - Fixed an issue when a shift count larger than ``__INT64_MAX__``, in a right
   shift operation, could result in missing warnings about
   ``shift count >= width of type`` or internal compiler error.
@@ -685,10 +702,26 @@ Bug Fixes in This Version
   (`#65568 <https://github.com/llvm/llvm-project/issues/65568>`_)
 - Fix an issue where clang doesn't respect detault template arguments that
   are added in a later redeclaration for CTAD.
-  Fixes (#69987 <https://github.com/llvm/llvm-project/issues/69987>`_)
+  Fixes (`#69987 <https://github.com/llvm/llvm-project/issues/69987>`_)
 - Fix an issue where CTAD fails for explicit type conversion.
-  Fixes (#64347 <https://github.com/llvm/llvm-project/issues/64347>`_)
-
+  Fixes (`#64347 <https://github.com/llvm/llvm-project/issues/64347>`_)
+- Fix crash when using C++ only tokens like ``::`` in C compiler clang.
+  Fixes (`#73559 <https://github.com/llvm/llvm-project/issues/73559>`_)
+- Clang now accepts recursive non-dependent calls to functions with deduced
+  return type.
+  Fixes (`#71015 <https://github.com/llvm/llvm-project/issues/71015>`_)
+- Fix assertion failure when initializing union containing struct with
+  flexible array member using empty initializer list.
+  Fixes (`#77085 <https://github.com/llvm/llvm-project/issues/77085>`_)
+- Fix assertion crash due to failed scope restoring caused by too-early VarDecl
+  invalidation by invalid initializer Expr.
+  Fixes (`#30908 <https://github.com/llvm/llvm-project/issues/30908>`_)
+- Clang now emits correct source location for code-coverage regions in `if constexpr`
+  and `if consteval` branches.
+  Fixes (`#54419 <https://github.com/llvm/llvm-project/issues/54419>`_)
+- Fix an issue where clang cannot find conversion function with template
+  parameter when instantiation of template class.
+  Fixes (`#77583 <https://github.com/llvm/llvm-project/issues/77583>`_)
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -716,7 +749,8 @@ Bug Fixes to C++ Support
 
 - Clang emits an error on substitution failure within lambda body inside a
   requires-expression. This fixes:
-  (`#64138 <https://github.com/llvm/llvm-project/issues/64138>`_).
+  (`#64138 <https://github.com/llvm/llvm-project/issues/64138>`_) and
+  (`#71684 <https://github.com/llvm/llvm-project/issues/71684>`_).
 
 - Update ``FunctionDeclBitfields.NumFunctionDeclBits``. This fixes:
   (`#64171 <https://github.com/llvm/llvm-project/issues/64171>`_).
@@ -843,6 +877,16 @@ Bug Fixes to C++ Support
 - Fix crash when parsing nested requirement. Fixes:
   (`#73112 <https://github.com/llvm/llvm-project/issues/73112>`_)
 
+- Fixed a crash caused by using return type requirement in a lambda. Fixes:
+  (`#63808 <https://github.com/llvm/llvm-project/issues/63808>`_)
+  (`#64607 <https://github.com/llvm/llvm-project/issues/64607>`_)
+  (`#64086 <https://github.com/llvm/llvm-project/issues/64086>`_)
+
+- Fixed a regression where clang forgets how to substitute into constraints on template-template
+  parameters. Fixes:
+  (`#57410 <https://github.com/llvm/llvm-project/issues/57410>`_) and
+  (`#76604 <https://github.com/llvm/llvm-project/issues/57410>`_)
+
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 - Fixed an import failure of recursive friend class template.
@@ -856,6 +900,9 @@ Bug Fixes to AST Handling
 - Fixed a bug where RecursiveASTVisitor fails to visit the
   initializer of a bitfield.
   `Issue 64916 <https://github.com/llvm/llvm-project/issues/64916>`_
+- Fixed a bug where range-loop-analysis checks for trivial copyability,
+  rather than trivial copy-constructibility
+  `Issue 47355 <https://github.com/llvm/llvm-project/issues/47355>`_
 - Fixed a bug where Template Instantiation failed to handle Lambda Expressions
   with certain types of Attributes.
   (`#76521 <https://github.com/llvm/llvm-project/issues/76521>`_)
@@ -913,6 +960,15 @@ X86 Support
   * Support intrinsic of ``_uwrmsr``.
 - Support ISA of ``AVX10.1``.
 - ``-march=pantherlake`` and ``-march=clearwaterforest`` are now supported.
+- Added ABI handling for ``__float128`` to match with GCC.
+- Emit warnings for options to enable knl/knm specific ISAs: AVX512PF, AVX512ER
+  and PREFETCHWT1. From next version (LLVM 19), these ISAs' intrinsic supports
+  will be deprecated:
+  * intrinsic series of *_exp2a23_*
+  * intrinsic series of *_rsqrt28_*
+  * intrinsic series of *_rcp28_*
+  * intrinsic series of *_prefetch_i[3|6][2|4]gather_*
+  * intrinsic series of *_prefetch_i[3|6][2|4]scatter_*
 
 Arm and AArch64 Support
 ^^^^^^^^^^^^^^^^^^^^^^^
@@ -1045,6 +1101,7 @@ clang-format
 - Add ``ObjCPropertyAttributeOrder`` which can be used to sort ObjC property
   attributes (like ``nonatomic, strong, nullable``).
 - Add ``.clang-format-ignore`` files.
+- Add ``AlignFunctionPointers`` sub-option for ``AlignConsecutiveDeclarations``.
 
 libclang
 --------
@@ -1130,9 +1187,10 @@ Improvements
 ^^^^^^^^^^^^
 
 - Improved the ``unix.StdCLibraryFunctions`` checker by modeling more
-  functions like ``send``, ``recv``, ``readlink``, ``fflush``, ``mkdtemp`` and
-  ``errno`` behavior.
+  functions like ``send``, ``recv``, ``readlink``, ``fflush``, ``mkdtemp``,
+  ``getcwd`` and ``errno`` behavior.
   (`52ac71f92d38 <https://github.com/llvm/llvm-project/commit/52ac71f92d38f75df5cb88e9c090ac5fd5a71548>`_,
+  `#77040 <https://github.com/llvm/llvm-project/pull/77040>`_,
   `#76671 <https://github.com/llvm/llvm-project/pull/76671>`_,
   `#71373 <https://github.com/llvm/llvm-project/pull/71373>`_,
   `#76557 <https://github.com/llvm/llvm-project/pull/76557>`_,
@@ -1161,16 +1219,18 @@ Improvements
   (`c3a87ddad62a <https://github.com/llvm/llvm-project/commit/c3a87ddad62a6cc01acaccc76592bc6730c8ac3c>`_,
   `0954dc3fb921 <https://github.com/llvm/llvm-project/commit/0954dc3fb9214b994623f5306473de075f8e3593>`_)
 
-- Improved the ``alpha.unix.Stream`` checker by modeling more functions like,
-  ``fflush``, ``fputs``, ``fgetc``, ``fputc``, ``fopen``, ``fdopen``, ``fgets``, ``tmpfile``.
+- Improved the ``alpha.unix.Stream`` checker by modeling more functions
+  ``fputs``, ``fputc``, ``fgets``, ``fgetc``, ``fdopen``, ``ungetc``, ``fflush``
+  and no not recognize alternative ``fopen`` and ``tmpfile`` implementations.
   (`#76776 <https://github.com/llvm/llvm-project/pull/76776>`_,
   `#74296 <https://github.com/llvm/llvm-project/pull/74296>`_,
   `#73335 <https://github.com/llvm/llvm-project/pull/73335>`_,
   `#72627 <https://github.com/llvm/llvm-project/pull/72627>`_,
   `#71518 <https://github.com/llvm/llvm-project/pull/71518>`_,
   `#72016 <https://github.com/llvm/llvm-project/pull/72016>`_,
   `#70540 <https://github.com/llvm/llvm-project/pull/70540>`_,
-  `#73638 <https://github.com/llvm/llvm-project/pull/73638>`_)
+  `#73638 <https://github.com/llvm/llvm-project/pull/73638>`_,
+  `#77331 <https://github.com/llvm/llvm-project/pull/77331>`_)
 
 - The ``alpha.security.taint.TaintPropagation`` checker no longer propagates
   taint on ``strlen`` and ``strnlen`` calls, unless these are marked

diff --git a/clang/include/clang/AST/Attr.h b/clang/include/clang/AST/Attr.h
@@ -25,6 +25,7 @@
 #include "clang/Basic/Sanitizers.h"
 #include "clang/Basic/SourceLocation.h"
 #include "llvm/Frontend/HLSL/HLSLResource.h"
+#include "llvm/Support/CodeGen.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/raw_ostream.h"

diff --git a/clang/include/clang/AST/DeclBase.h b/clang/include/clang/AST/DeclBase.h
@@ -19,6 +19,7 @@
 #include "clang/AST/SelectorLocationsKind.h"
 #include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/LLVM.h"
+#include "clang/Basic/LangOptions.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/Specifiers.h"
 #include "llvm/ADT/ArrayRef.h"
@@ -488,6 +489,15 @@ class alignas(8) Decl {
   // Return true if this is a FileContext Decl.
   bool isFileContextDecl() const;
 
+  /// Whether it resembles a flexible array member. This is a static member
+  /// because we want to be able to call it with a nullptr. That allows us to
+  /// perform non-Decl specific checks based on the object's type and strict
+  /// flex array level.
+  static bool isFlexibleArrayMemberLike(
+      ASTContext &Context, const Decl *D, QualType Ty,
+      LangOptions::StrictFlexArraysLevelKind StrictFlexArraysLevel,
+      bool IgnoreTemplateOrMacroSubstitution);
+
   ASTContext &getASTContext() const LLVM_READONLY;
 
   /// Helper to get the language options from the ASTContext.

diff --git a/clang/include/clang/AST/DeclCXX.h b/clang/include/clang/AST/DeclCXX.h
@@ -1425,6 +1425,9 @@ class CXXRecordDecl : public RecordDecl {
   /// (C++11 [class]p6).
   bool isTriviallyCopyable() const;
 
+  /// Determine whether this class is considered trivially copyable per
+  bool isTriviallyCopyConstructible() const;
+
   /// Determine whether this class is considered trivial.
   ///
   /// C++11 [class]p6:

diff --git a/clang/include/clang/AST/Stmt.h b/clang/include/clang/AST/Stmt.h
@@ -1631,8 +1631,10 @@ class CompoundStmt final
                               SourceLocation RB);
 
   // Build an empty compound statement with a location.
-  explicit CompoundStmt(SourceLocation Loc)
-      : Stmt(CompoundStmtClass), LBraceLoc(Loc), RBraceLoc(Loc) {
+  explicit CompoundStmt(SourceLocation Loc) : CompoundStmt(Loc, Loc) {}
+
+  CompoundStmt(SourceLocation Loc, SourceLocation EndLoc)
+      : Stmt(CompoundStmtClass), LBraceLoc(Loc), RBraceLoc(EndLoc) {
     CompoundStmtBits.NumStmts = 0;
     CompoundStmtBits.HasFPFeatures = 0;
   }

diff --git a/clang/include/clang/AST/TextNodeDumper.h b/clang/include/clang/AST/TextNodeDumper.h
@@ -252,6 +252,8 @@ class TextNodeDumper
   void VisitGotoStmt(const GotoStmt *Node);
   void VisitCaseStmt(const CaseStmt *Node);
   void VisitReturnStmt(const ReturnStmt *Node);
+  void VisitCoawaitExpr(const CoawaitExpr *Node);
+  void VisitCoreturnStmt(const CoreturnStmt *Node);
   void VisitCompoundStmt(const CompoundStmt *Node);
   void VisitConstantExpr(const ConstantExpr *Node);
   void VisitCallExpr(const CallExpr *Node);

diff --git a/clang/include/clang/AST/Type.h b/clang/include/clang/AST/Type.h
@@ -917,6 +917,9 @@ class QualType {
   /// Return true if this is a trivially copyable type (C++0x [basic.types]p9)
   bool isTriviallyCopyableType(const ASTContext &Context) const;
 
+  /// Return true if this is a trivially copyable type
+  bool isTriviallyCopyConstructibleType(const ASTContext &Context) const;
+
   /// Return true if this is a trivially relocatable type.
   bool isTriviallyRelocatableType(const ASTContext &Context) const;
 
@@ -4224,6 +4227,8 @@ class FunctionProtoType final
     ExceptionSpecInfo() = default;
 
     ExceptionSpecInfo(ExceptionSpecificationType EST) : Type(EST) {}
+
+    void instantiate();
   };
 
   /// Extra information about a function prototype. ExtProtoInfo is not

diff --git a/clang/include/clang/Analysis/CFG.h b/clang/include/clang/Analysis/CFG.h
@@ -1215,7 +1215,9 @@ class CFG {
   //===--------------------------------------------------------------------===//
 
   class BuildOptions {
-    std::bitset<Stmt::lastStmtConstant> alwaysAddMask;
+    // Stmt::lastStmtConstant has the same value as the last Stmt kind,
+    // so make sure we add one to account for this!
+    std::bitset<Stmt::lastStmtConstant + 1> alwaysAddMask;
 
   public:
     using ForcedBlkExprs = llvm::DenseMap<const Stmt *, const CFGBlock *>;

diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
@@ -143,6 +143,11 @@ def ExternalGlobalVar : SubsetSubject<Var,
                                !S->isLocalExternDecl()}],
                              "external global variables">;
 
+def NonTLSGlobalVar : SubsetSubject<Var,
+                             [{S->hasGlobalStorage() &&
+                               S->getTLSKind() == 0}],
+                             "non-TLS global variables">;
+
 def InlineFunction : SubsetSubject<Function,
                              [{S->isInlineSpecified()}], "inline functions">;
 
@@ -431,6 +436,7 @@ def TargetAArch64 : TargetArch<["aarch64", "aarch64_be", "aarch64_32"]>;
 def TargetAnyArm : TargetArch<!listconcat(TargetARM.Arches, TargetAArch64.Arches)>;
 def TargetAVR : TargetArch<["avr"]>;
 def TargetBPF : TargetArch<["bpfel", "bpfeb"]>;
+def TargetLoongArch : TargetArch<["loongarch32", "loongarch64"]>;
 def TargetMips32 : TargetArch<["mips", "mipsel"]>;
 def TargetAnyMips : TargetArch<["mips", "mipsel", "mips64", "mips64el"]>;
 def TargetMSP430 : TargetArch<["msp430"]>;
@@ -1121,6 +1127,14 @@ def CoroLifetimeBound : InheritableAttr {
   let SimpleHandler = 1;
 }
 
+def CoroDisableLifetimeBound : InheritableAttr {
+  let Spellings = [Clang<"coro_disable_lifetimebound">];
+  let Subjects = SubjectList<[Function]>;
+  let LangOpts = [CPlusPlus];
+  let Documentation = [CoroLifetimeBoundDoc];
+  let SimpleHandler = 1;
+}
+
 // OSObject-based attributes.
 def OSConsumed : InheritableParamAttr {
   let Spellings = [Clang<"os_consumed">];
@@ -2730,6 +2744,15 @@ def PragmaClangTextSection : InheritableAttr {
   let Documentation = [InternalOnly];
 }
 
+def CodeModel : InheritableAttr, TargetSpecificAttr<TargetLoongArch> {
+  let Spellings = [GCC<"model">];
+  let Args = [EnumArgument<"Model", "llvm::CodeModel::Model",
+              ["normal", "medium", "extreme"], ["Small", "Medium", "Large"],
+              /*opt=*/0, /*fake=*/0, /*isExternalType=*/1>];
+  let Subjects = SubjectList<[NonTLSGlobalVar], ErrorDiag>;
+  let Documentation = [CodeModelDocs];
+}
+
 def Sentinel : InheritableAttr {
   let Spellings = [GCC<"sentinel">];
   let Args = [DefaultIntArgument<"Sentinel", 0>,
@@ -4349,3 +4372,21 @@ def CodeAlign: StmtAttr {
     static constexpr int MaximumAlignment = 4096;
   }];
 }
+
+def CountedBy : InheritableAttr {
+  let Spellings = [Clang<"counted_by">];
+  let Subjects = SubjectList<[Field]>;
+  let Args = [IdentifierArgument<"CountedByField">];
+  let Documentation = [CountedByDocs];
+  let LangOpts = [COnly];
+  // FIXME: This is ugly. Let using a DeclArgument would be nice, but a Decl
+  // isn't yet available due to the fact that we're still parsing the
+  // structure. Maybe that code could be changed sometime in the future.
+  code AdditionalMembers = [{
+    private:
+      SourceRange CountedByFieldLoc;
+    public:
+      SourceRange getCountedByFieldLoc() const { return CountedByFieldLoc; }
+      void setCountedByFieldLoc(SourceRange Loc) { CountedByFieldLoc = Loc; }
+  }];
+}
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
@@ -57,6 +57,15 @@ global variable or function should be in after translation.
   let Heading = "section, __declspec(allocate)";
 }
 
+def CodeModelDocs : Documentation {
+  let Category = DocCatVariable;
+  let Content = [{
+The ``model`` attribute allows overriding the translation unit's
+code model (specified by ``-mcmodel``) for a specific global variable.
+  }];
+  let Heading = "model";
+}
+
 def UsedDocs : Documentation {
   let Category = DocCatFunction;
   let Content = [{
@@ -7671,9 +7680,12 @@ The ``[[clang::coro_lifetimebound]]`` is a class attribute which can be applied
 to a coroutine return type (`CRT`_) (i.e.
 it should also be annotated with ``[[clang::coro_return_type]]``).
 
-All parameters of a function are considered to be lifetime bound. See `documentation`_
-of ``[[clang::lifetimebound]]`` for more details.
-if the function returns a coroutine return type (CRT) annotated with ``[[clang::coro_lifetimebound]]``.
+All parameters of a function are considered to be lifetime bound if the function returns a
+coroutine return type (CRT) annotated with ``[[clang::coro_lifetimebound]]``.
+This lifetime bound analysis can be disabled for a coroutine wrapper or a coroutine by annotating the function
+with ``[[clang::coro_disable_lifetimebound]]`` function attribute .
+See `documentation`_ of ``[[clang::lifetimebound]]`` for details about lifetime bound analysis.
+
 
 Reference parameters of a coroutine are susceptible to capturing references to temporaries or local variables.
 
@@ -7703,7 +7715,7 @@ Both coroutines and coroutine wrappers are part of this analysis.
   };
 
   Task<int> coro(const int& a) { co_return a + 1; }
-  Task<int> [[clang::coro_wrapper]] coro_wrapper(const int& a, const int& b) {
+  [[clang::coro_wrapper]] Task<int> coro_wrapper(const int& a, const int& b) {
     return a > b ? coro(a) : coro(b);
   }
   Task<int> temporary_reference() {
@@ -7718,7 +7730,100 @@ Both coroutines and coroutine wrappers are part of this analysis.
     return coro(a); // warning: returning address of stack variable `a`.
   }
 
+This analysis can be disabled for all calls to a particular function by annotating the function
+with function attribute ``[[clang::coro_disable_lifetimebound]]``.
+For example, this could be useful for coroutine wrappers which accept reference parameters
+but do not pass them to the underlying coroutine or pass them by value.
+
+.. code-block:: c++
+
+  Task<int> coro(int a) { co_return a + 1; }
+  [[clang::coro_wrapper, clang::coro_disable_lifetimebound]] Task<int> coro_wrapper(const int& a) {
+    return coro(a + 1);
+  }
+  void use() {
+    auto task = coro_wrapper(1); // use of temporary is fine as the argument is not lifetime bound.
+  }
+
 .. _`documentation`: https://clang.llvm.org/docs/AttributeReference.html#lifetimebound
 .. _`CRT`: https://clang.llvm.org/docs/AttributeReference.html#coro-return-type
 }];
 }
+
+def CountedByDocs : Documentation {
+  let Category = DocCatField;
+  let Content = [{
+Clang supports the ``counted_by`` attribute on the flexible array member of a
+structure in C. The argument for the attribute is the name of a field member
+holding the count of elements in the flexible array. This information can be
+used to improve the results of the array bound sanitizer and the
+``__builtin_dynamic_object_size`` builtin. The ``count`` field member must be
+within the same non-anonymous, enclosing struct as the flexible array member.
+
+This example specifies that the flexible array member ``array`` has the number
+of elements allocated for it in ``count``:
+
+.. code-block:: c
+
+  struct bar;
+
+  struct foo {
+    size_t count;
+    char other;
+    struct bar *array[] __attribute__((counted_by(count)));
+  };
+
+This establishes a relationship between ``array`` and ``count``. Specifically,
+``array`` must have at least ``count`` number of elements available. It's the
+user's responsibility to ensure that this relationship is maintained through
+changes to the structure.
+
+In the following example, the allocated array erroneously has fewer elements
+than what's specified by ``p->count``. This would result in an out-of-bounds
+access not being detected.
+
+.. code-block:: c
+
+  #define SIZE_INCR 42
+
+  struct foo *p;
+
+  void foo_alloc(size_t count) {
+    p = malloc(MAX(sizeof(struct foo),
+                   offsetof(struct foo, array[0]) + count * sizeof(struct bar *)));
+    p->count = count + SIZE_INCR;
+  }
+
+The next example updates ``p->count``, but breaks the relationship requirement
+that ``p->array`` must have at least ``p->count`` number of elements available:
+
+.. code-block:: c
+
+  #define SIZE_INCR 42
+
+  struct foo *p;
+
+  void foo_alloc(size_t count) {
+    p = malloc(MAX(sizeof(struct foo),
+                   offsetof(struct foo, array[0]) + count * sizeof(struct bar *)));
+    p->count = count;
+  }
+
+  void use_foo(int index, int val) {
+    p->count += SIZE_INCR + 1; /* 'count' is now larger than the number of elements of 'array'. */
+    p->array[index] = val;     /* The sanitizer can't properly check this access. */
+  }
+
+In this example, an update to ``p->count`` maintains the relationship
+requirement:
+
+.. code-block:: c
+
+  void use_foo(int index, int val) {
+    if (p->count == 0)
+      return;
+    --p->count;
+    p->array[index] = val;
+  }
+  }];
+}
diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def
@@ -209,6 +209,7 @@ CODEGENOPT(CoverageMapping , 1, 0) ///< Generate coverage mapping regions to
                                    ///< enable code coverage analysis.
 CODEGENOPT(DumpCoverageMapping , 1, 0) ///< Dump the generated coverage mapping
                                        ///< regions.
+CODEGENOPT(MCDCCoverage , 1, 0) ///< Enable MC/DC code coverage criteria.
 
   /// If -fpcc-struct-return or -freg-struct-return is specified.
 ENUM_CODEGENOPT(StructReturnConvention, StructReturnConventionKind, 2, SRCK_Default)

diff --git a/clang/include/clang/Basic/DiagnosticCommonKinds.td b/clang/include/clang/Basic/DiagnosticCommonKinds.td
@@ -349,6 +349,9 @@ def warn_invalid_feature_combination : Warning<
 def warn_target_unrecognized_env : Warning<
   "mismatch between architecture and environment in target triple '%0'; did you mean '%1'?">,
   InGroup<InvalidCommandLineArgument>;
+def warn_knl_knm_isa_support_removed : Warning<
+  "KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.">,
+  InGroup<DiagGroup<"knl-knm-isa-support-removed">>;
 
 // Source manager
 def err_cannot_open_file : Error<"cannot open file '%0': %1">, DefaultFatal;

diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -786,4 +786,7 @@ def warn_android_unversioned_fallback : Warning<
   " directories will not be used in Clang 19. Provide a versioned directory"
   " for the target version or lower instead.">,
   InGroup<DiagGroup<"android-unversioned-fallback">>;
+
+def err_drv_triple_version_invalid : Error<
+  "version '%0' in target triple '%1' is invalid">;
 }
diff --git a/clang/include/clang/Basic/DiagnosticFrontendKinds.td b/clang/include/clang/Basic/DiagnosticFrontendKinds.td
@@ -167,7 +167,7 @@ def err_verify_no_such_marker : Error<
 def err_verify_missing_start : Error<
     "cannot find start ('{{') of expected %0">;
 def err_verify_missing_end : Error<
-    "cannot find end ('}}') of expected %0">;
+    "cannot find end ('%1') of expected %0">;
 def err_verify_invalid_content : Error<
     "invalid expected %0: %1">;
 def err_verify_missing_regex : Error<

diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -1364,6 +1364,8 @@ def err_acc_invalid_clause : Error<"invalid OpenACC clause %0">;
 def err_acc_missing_directive : Error<"expected OpenACC directive">;
 def err_acc_invalid_open_paren
     : Error<"expected clause-list or newline in OpenACC directive">;
+def err_acc_invalid_default_clause_kind
+    : Error<"invalid value for 'default' clause; expected 'present' or 'none'">;
 
 // OpenMP support.
 def warn_pragma_omp_ignored : Warning<

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2253,6 +2253,8 @@ def warn_cxx17_compat_aggregate_init_paren_list : Warning<
 def err_reference_bind_to_bitfield : Error<
   "%select{non-const|volatile}0 reference cannot bind to "
   "bit-field%select{| %1}2">;
+def err_reference_bind_to_bitfield_in_cce : Error<
+  "reference cannot bind to bit-field in converted constant expression">;
 def err_reference_bind_to_vector_element : Error<
   "%select{non-const|volatile}0 reference cannot bind to vector element">;
 def err_reference_bind_to_matrix_element : Error<
@@ -3415,6 +3417,8 @@ def warn_objc_redundant_literal_use : Warning<
 def err_attr_tlsmodel_arg : Error<"tls_model must be \"global-dynamic\", "
   "\"local-dynamic\", \"initial-exec\" or \"local-exec\"">;
 
+def err_attr_codemodel_arg : Error<"code model '%0' is not supported on this target">;
+
 def err_aix_attr_unsupported_tls_model : Error<"TLS model '%0' is not yet supported on AIX">;
 
 def err_tls_var_aligned_over_maximum : Error<
@@ -6158,23 +6162,19 @@ def err_illegal_initializer_type : Error<"illegal initializer type %0">;
 def ext_init_list_type_narrowing : ExtWarn<
   "type %0 cannot be narrowed to %1 in initializer list">,
   InGroup<CXX11Narrowing>, DefaultError, SFINAEFailure;
-// *_narrowing_const_reference diagnostics have the same messages, but are
-// controlled by -Wc++11-narrowing-const-reference for narrowing involving a
-// const reference.
 def ext_init_list_type_narrowing_const_reference : ExtWarn<
-  "type %0 cannot be narrowed to %1 in initializer list">,
+  ext_init_list_type_narrowing.Summary>,
   InGroup<CXX11NarrowingConstReference>, DefaultError, SFINAEFailure;
 def ext_init_list_variable_narrowing : ExtWarn<
   "non-constant-expression cannot be narrowed from type %0 to %1 in "
   "initializer list">, InGroup<CXX11Narrowing>, DefaultError, SFINAEFailure;
 def ext_init_list_variable_narrowing_const_reference : ExtWarn<
-  "non-constant-expression cannot be narrowed from type %0 to %1 in "
-  "initializer list">, InGroup<CXX11NarrowingConstReference>, DefaultError, SFINAEFailure;
+  ext_init_list_variable_narrowing.Summary>, InGroup<CXX11NarrowingConstReference>, DefaultError, SFINAEFailure;
 def ext_init_list_constant_narrowing : ExtWarn<
   "constant expression evaluates to %0 which cannot be narrowed to type %1">,
   InGroup<CXX11Narrowing>, DefaultError, SFINAEFailure;
 def ext_init_list_constant_narrowing_const_reference : ExtWarn<
-  "constant expression evaluates to %0 which cannot be narrowed to type %1">,
+  ext_init_list_constant_narrowing.Summary>,
   InGroup<CXX11NarrowingConstReference>, DefaultError, SFINAEFailure;
 def warn_init_list_type_narrowing : Warning<
   "type %0 cannot be narrowed to %1 in initializer list in C++11">,
@@ -6441,6 +6441,19 @@ def warn_superclass_variable_sized_type_not_at_end : Warning<
   "field %0 can overwrite instance variable %1 with variable sized type %2"
   " in superclass %3">, InGroup<ObjCFlexibleArray>;
 
+def err_flexible_array_count_not_in_same_struct : Error<
+  "'counted_by' field %0 isn't within the same struct as the flexible array">;
+def err_counted_by_attr_not_on_flexible_array_member : Error<
+  "'counted_by' only applies to C99 flexible array members">;
+def err_counted_by_attr_refers_to_flexible_array : Error<
+  "'counted_by' cannot refer to the flexible array %0">;
+def err_counted_by_must_be_in_structure : Error<
+  "field %0 in 'counted_by' not inside structure">;
+def err_flexible_array_counted_by_attr_field_not_integer : Error<
+  "field %0 in 'counted_by' must be a non-boolean integer type">;
+def note_flexible_array_counted_by_attr_field : Note<
+  "field %0 declared here">;
+
 let CategoryName = "ARC Semantic Issue" in {
 
 // ARC-mode diagnostics.

diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
@@ -457,6 +457,7 @@ ENUM_LANGOPT(SignReturnAddressKey, SignReturnAddressKeyKind, 1, SignReturnAddres
              "Key used for return address signing")
 LANGOPT(BranchTargetEnforcement, 1, 0, "Branch-target enforcement enabled")
 LANGOPT(BranchProtectionPAuthLR, 1, 0, "Use PC as a diversifier using PAuthLR NOP instructions.")
+LANGOPT(GuardedControlStack, 1, 0, "Guarded control stack enabled")
 
 LANGOPT(SpeculativeLoadHardening, 1, 0, "Speculative load hardening enabled")
 

diff --git a/clang/include/clang/Basic/OpenACCKinds.h b/clang/include/clang/Basic/OpenACCKinds.h
@@ -72,25 +72,47 @@ enum class OpenACCAtomicKind {
 
 /// Represents the kind of an OpenACC clause.
 enum class OpenACCClauseKind {
-  // 'finalize' clause, allowed on 'exit data' directive.
+  /// 'finalize' clause, allowed on 'exit data' directive.
   Finalize,
-  // 'if_present' clause, allowed on 'host_data' and 'update' directives.
+  /// 'if_present' clause, allowed on 'host_data' and 'update' directives.
   IfPresent,
-  // 'seq' clause, allowed on 'loop' and 'routine' directives.
+  /// 'seq' clause, allowed on 'loop' and 'routine' directives.
   Seq,
-  // 'independent' clause, allowed on 'loop' directives.
+  /// 'independent' clause, allowed on 'loop' directives.
   Independent,
-  // 'auto' clause, allowed on 'loop' directives.
+  /// 'auto' clause, allowed on 'loop' directives.
   Auto,
-  // 'worker' clause, allowed on 'loop' and 'routine' directives.
+  /// 'worker' clause, allowed on 'loop' and 'routine' directives.
   Worker,
-  // 'vector' clause, allowed on 'loop' and 'routine' directives. Takes no
-  // arguments for 'routine', so the 'loop' version is not yet implemented
-  // completely.
+  /// 'vector' clause, allowed on 'loop' and 'routine' directives. Takes no
+  /// arguments for 'routine', so the 'loop' version is not yet implemented
+  /// completely.
   Vector,
-  // 'nohost' clause, allowed on 'routine' directives.
+  /// 'nohost' clause, allowed on 'routine' directives.
   NoHost,
-  // Represents an invalid clause, for the purposes of parsing.
+  /// 'default' clause, allowed on parallel, serial, kernel (and compound)
+  /// constructs.
+  Default,
+  /// 'if' clause, allowed on all the Compute Constructs, Data Constructs,
+  /// Executable Constructs, and Combined Constructs.
+  If,
+  /// 'self' clause, allowed on Compute and Combined Constructs, plus 'update'.
+  Self,
+  /// 'copy' clause, allowed on Compute and Combined Constructs, plus 'data' and
+  /// 'declare'.
+  Copy,
+  /// 'use_device' clause, allowed on 'host_data' construct.
+  UseDevice,
+  /// Represents an invalid clause, for the purposes of parsing.
+  Invalid,
+};
+
+enum class OpenACCDefaultClauseKind {
+  /// 'none' option.
+  None,
+  /// 'present' option.
+  Present,
+  /// Not a valid option.
   Invalid,
 };
 } // namespace clang

diff --git a/clang/include/clang/Basic/TargetInfo.h b/clang/include/clang/Basic/TargetInfo.h
@@ -1373,6 +1373,7 @@ class TargetInfo : public TransferrableTargetInfo,
         LangOptions::SignReturnAddressKeyKind::AKey;
     bool BranchTargetEnforcement = false;
     bool BranchProtectionPAuthLR = false;
+    bool GuardedControlStack = false;
   };
 
   /// Determine if the Architecture in this TargetInfo supports branch

diff --git a/clang/include/clang/Basic/arm_sve.td b/clang/include/clang/Basic/arm_sve.td
diff --git a/clang/include/clang/Basic/arm_sve_sme_incl.td b/clang/include/clang/Basic/arm_sve_sme_incl.td
@@ -227,6 +227,7 @@ def IsPreservesZA             : FlagType<0x10000000000>;
 def IsReadZA                  : FlagType<0x20000000000>;
 def IsWriteZA                 : FlagType<0x40000000000>;
 def IsReductionQV             : FlagType<0x80000000000>;
+def IsStreamingOrSVE2p1       : FlagType<0x80000000000>; // Use for intrinsics that are common between sme/sme2 and sve2p1.
 
 // These must be kept in sync with the flags in include/clang/Basic/TargetBuiltins.h
 class ImmCheckType<int val> {

diff --git a/clang/include/clang/Basic/riscv_sifive_vector.td b/clang/include/clang/Basic/riscv_sifive_vector.td
@@ -121,11 +121,11 @@ multiclass RVVVQMACCDODBuiltinSet<list<list<string>> suffixes_prototypes> {
 }
 
 multiclass RVVVQMACCQOQBuiltinSet<list<list<string>> suffixes_prototypes> {
-   let OverloadedName = NAME,
-       Name = NAME,
-       HasMasked = false,
-       Log2LMUL = [-1, 0, 1, 2] in
-     defm NAME : RVVOutOp1Op2BuiltinSet<NAME, "s", suffixes_prototypes>;
+  let OverloadedName = NAME,
+      Name = NAME,
+      HasMasked = false,
+      Log2LMUL = [-1, 0, 1, 2] in
+    defm NAME : RVVOutOp1Op2BuiltinSet<NAME, "s", suffixes_prototypes>;
 }
 
 multiclass RVVVFNRCLIPBuiltinSet<string suffix, string prototype, string type_range> {

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
@@ -773,6 +773,8 @@ def gcc_install_dir_EQ : Joined<["--"], "gcc-install-dir=">,
 def gcc_toolchain : Joined<["--"], "gcc-toolchain=">, Flags<[NoXarchOption]>,
   HelpText<"Specify a directory where Clang can find 'include' and 'lib{,32,64}/gcc{,-cross}/$triple/$version'. "
   "Clang will use the GCC installation with the largest version">;
+def gcc_triple_EQ : Joined<["--"], "gcc-triple=">,
+  HelpText<"Search for the GCC installation with the specified triple.">;
 def CC : Flag<["-"], "CC">, Visibility<[ClangOption, CC1Option]>,
   Group<Preprocessor_Group>,
     HelpText<"Include comments from within macros in preprocessed output">,
@@ -1695,6 +1697,12 @@ defm coverage_mapping : BoolFOption<"coverage-mapping",
           "Generate coverage mapping to enable code coverage analysis">,
   NegFlag<SetFalse, [], [ClangOption], "Disable code coverage analysis">, BothFlags<
           [], [ClangOption, CLOption]>>;
+defm mcdc_coverage : BoolFOption<"coverage-mcdc",
+  CodeGenOpts<"MCDCCoverage">, DefaultFalse,
+  PosFlag<SetTrue, [], [ClangOption, CC1Option],
+          "Enable MC/DC criteria when generating code coverage">,
+  NegFlag<SetFalse, [], [ClangOption], "Disable MC/DC coverage criteria">,
+          BothFlags<[], [ClangOption, CLOption]>>;
 def fprofile_generate : Flag<["-"], "fprofile-generate">,
     Group<f_Group>, Visibility<[ClangOption, CLOption]>,
     HelpText<"Generate instrumented code to collect execution counts into default.profraw (overridden by LLVM_PROFILE_FILE env var)">;
@@ -4259,7 +4267,7 @@ def iquote : JoinedOrSeparate<["-"], "iquote">, Group<clang_i_Group>,
   Visibility<[ClangOption, CC1Option]>,
   HelpText<"Add directory to QUOTE include search path">, MetaVarName<"<directory>">;
 def isysroot : JoinedOrSeparate<["-"], "isysroot">, Group<clang_i_Group>,
-  Visibility<[ClangOption, CC1Option]>,
+  Visibility<[ClangOption, CC1Option, FlangOption]>,
   HelpText<"Set the system root directory (usually /)">, MetaVarName<"<dir>">,
   MarshallingInfoString<HeaderSearchOpts<"Sysroot">, [{"/"}]>;
 def isystem : JoinedOrSeparate<["-"], "isystem">, Group<clang_i_Group>,
@@ -4577,11 +4585,13 @@ let Flags = [TargetSpecific] in {
 def menable_experimental_extensions : Flag<["-"], "menable-experimental-extensions">, Group<m_Group>,
   HelpText<"Enable use of experimental RISC-V extensions.">;
 def mrvv_vector_bits_EQ : Joined<["-"], "mrvv-vector-bits=">, Group<m_Group>,
-  HelpText<"Specify the size in bits of an RVV vector register. Defaults to "
-           "the vector length agnostic value of \"scalable\". Accepts power of "
-           "2 values between 64 and 65536. Also accepts \"zvl\" "
-           "to use the value implied by -march/-mcpu. Value will be reflected "
-           "in __riscv_v_fixed_vlen preprocessor define (RISC-V only)">;
+  Visibility<[ClangOption, FlangOption]>,
+  HelpText<"Specify the size in bits of an RVV vector register">,
+  DocBrief<"Defaults to the vector length agnostic value of \"scalable\". "
+           "Accepts power of 2 values between 64 and 65536. Also accepts "
+           "\"zvl\" to use the value implied by -march/-mcpu. On Clang, value "
+           "will be reflected in __riscv_v_fixed_vlen preprocessor define "
+           "(RISC-V only)">;
 
 def munaligned_access : Flag<["-"], "munaligned-access">, Group<m_Group>,
   HelpText<"Allow memory accesses to be unaligned (AArch32/AArch64/LoongArch/RISC-V only)">;
@@ -5189,12 +5199,12 @@ def nohipwrapperinc : Flag<["-"], "nohipwrapperinc">, Group<IncludePath_Group>,
   HelpText<"Do not include the default HIP wrapper headers and include paths">;
 def : Flag<["-"], "nocudainc">, Alias<nogpuinc>;
 def nogpulib : Flag<["-"], "nogpulib">, MarshallingInfoFlag<LangOpts<"NoGPULib">>,
-  Visibility<[ClangOption, CC1Option]>,
+  Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
   HelpText<"Do not link device library for CUDA/HIP device compilation">;
 def : Flag<["-"], "nocudalib">, Alias<nogpulib>;
-def gpulibc : Flag<["-"], "gpulibc">, Visibility<[ClangOption, CC1Option]>,
+def gpulibc : Flag<["-"], "gpulibc">, Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
   HelpText<"Link the LLVM C Library for GPUs">;
-def nogpulibc : Flag<["-"], "nogpulibc">, Visibility<[ClangOption, CC1Option]>;
+def nogpulibc : Flag<["-"], "nogpulibc">, Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>;
 def nodefaultlibs : Flag<["-"], "nodefaultlibs">;
 def nodriverkitlib : Flag<["-"], "nodriverkitlib">;
 def nofixprebinding : Flag<["-"], "nofixprebinding">;
@@ -7002,6 +7012,8 @@ def mbranch_target_enforce : Flag<["-"], "mbranch-target-enforce">,
   MarshallingInfoFlag<LangOpts<"BranchTargetEnforcement">>;
 def mbranch_protection_pauth_lr : Flag<["-"], "mbranch-protection-pauth-lr">,
   MarshallingInfoFlag<LangOpts<"BranchProtectionPAuthLR">>;
+def mguarded_control_stack : Flag<["-"], "mguarded-control-stack">,
+  MarshallingInfoFlag<LangOpts<"GuardedControlStack">>;
 def fno_dllexport_inlines : Flag<["-"], "fno-dllexport-inlines">,
   MarshallingInfoNegativeFlag<LangOpts<"DllExportInlines">>;
 def cfguard_no_checks : Flag<["-"], "cfguard-no-checks">,

diff --git a/clang/include/clang/Format/.clang-format b/clang/include/clang/Format/.clang-format
@@ -1 +1,6 @@
-BasedOnStyle: clang-format
+BasedOnStyle: LLVM
+InsertBraces: true
+InsertNewlineAtEOF: true
+LineEnding: LF
+RemoveBracesLLVM: true
+RemoveParentheses: ReturnStatement
diff --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
@@ -225,6 +225,22 @@ struct FormatStyle {
     ///   bbb = 2;
     /// \endcode
     bool AlignCompound;
+    /// Only for ``AlignConsecutiveDeclarations``. Whether function pointers are
+    /// aligned.
+    /// \code
+    ///   true:
+    ///   unsigned i;
+    ///   int     &r;
+    ///   int     *p;
+    ///   int      (*f)();
+    ///
+    ///   false:
+    ///   unsigned i;
+    ///   int     &r;
+    ///   int     *p;
+    ///   int (*f)();
+    /// \endcode
+    bool AlignFunctionPointers;
     /// Only for ``AlignConsecutiveAssignments``.  Whether short assignment
     /// operators are left-padded to the same length as long ones in order to
     /// put all assignment operators to the right of the left hand side.
@@ -247,7 +263,9 @@ struct FormatStyle {
     bool operator==(const AlignConsecutiveStyle &R) const {
       return Enabled == R.Enabled && AcrossEmptyLines == R.AcrossEmptyLines &&
              AcrossComments == R.AcrossComments &&
-             AlignCompound == R.AlignCompound && PadOperators == R.PadOperators;
+             AlignCompound == R.AlignCompound &&
+             AlignFunctionPointers == R.AlignFunctionPointers &&
+             PadOperators == R.PadOperators;
     }
     bool operator!=(const AlignConsecutiveStyle &R) const {
       return !(*this == R);
@@ -3037,6 +3055,7 @@ struct FormatStyle {
   bool isProto() const {
     return Language == LK_Proto || Language == LK_TextProto;
   }
+  bool isTableGen() const { return Language == LK_TableGen; }
 
   /// Language, this format style is targeted at.
   /// \version 3.5

diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
@@ -13,6 +13,7 @@
 #ifndef LLVM_CLANG_PARSE_PARSER_H
 #define LLVM_CLANG_PARSE_PARSER_H
 
+#include "clang/Basic/OpenACCKinds.h"
 #include "clang/Basic/OperatorPrecedence.h"
 #include "clang/Lex/CodeCompletionHandler.h"
 #include "clang/Lex/Preprocessor.h"
@@ -234,6 +235,26 @@ class Parser : public CodeCompletionHandler {
   /// Parsing OpenACC directive mode.
   bool OpenACCDirectiveParsing = false;
 
+  /// Currently parsing a situation where an OpenACC array section could be
+  /// legal, such as a 'var-list'.
+  bool AllowOpenACCArraySections = false;
+
+  /// RAII object to set reset OpenACC parsing a context where Array Sections
+  /// are allowed.
+  class OpenACCArraySectionRAII {
+    Parser &P;
+
+  public:
+    OpenACCArraySectionRAII(Parser &P) : P(P) {
+      assert(!P.AllowOpenACCArraySections);
+      P.AllowOpenACCArraySections = true;
+    }
+    ~OpenACCArraySectionRAII() {
+      assert(P.AllowOpenACCArraySections);
+      P.AllowOpenACCArraySections = false;
+    }
+  };
+
   /// When true, we are directly inside an Objective-C message
   /// send expression.
   ///
@@ -3546,8 +3567,18 @@ class Parser : public CodeCompletionHandler {
   ExprResult ParseOpenACCIDExpression();
   /// Parses the variable list for the `cache` construct.
   void ParseOpenACCCacheVarList();
-  /// Parses a single variable in a variable list for the 'cache' construct.
-  bool ParseOpenACCCacheVar();
+  /// Parses a single variable in a variable list for OpenACC.
+  bool ParseOpenACCVar();
+  /// Parses the variable list for the variety of clauses that take a var-list,
+  /// including the optional Special Token listed for some,based on clause type.
+  bool ParseOpenACCClauseVarList(OpenACCClauseKind Kind);
+  /// Parses any parameters for an OpenACC Clause, including required/optional
+  /// parens.
+  bool ParseOpenACCClauseParams(OpenACCClauseKind Kind);
+  /// Parses a single clause in a clause-list for OpenACC.
+  bool ParseOpenACCClause();
+  /// Parses the clause-list for an OpenACC directive.
+  void ParseOpenACCClauseList();
   bool ParseOpenACCWaitArgument();
 
 private:

diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
@@ -4799,6 +4799,8 @@ class Sema final {
   bool CheckAlwaysInlineAttr(const Stmt *OrigSt, const Stmt *CurSt,
                              const AttributeCommonInfo &A);
 
+  bool CheckCountedByAttr(Scope *Scope, const FieldDecl *FD);
+
   /// Adjust the calling convention of a method to be the ABI default if it
   /// wasn't specified explicitly.  This handles method types formed from
   /// function type typedefs and typename template arguments.
@@ -5642,6 +5644,7 @@ class Sema final {
                       CorrectionCandidateCallback &CCC,
                       TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr,
                       ArrayRef<Expr *> Args = std::nullopt,
+                      DeclContext *LookupCtx = nullptr,
                       TypoExpr **Out = nullptr);
 
   DeclResult LookupIvarInObjCMethod(LookupResult &Lookup, Scope *S,
@@ -11346,9 +11349,12 @@ class Sema final {
   /// rigorous semantic checking in the new mapped directives.
   bool mapLoopConstruct(llvm::SmallVector<OMPClause *> &ClausesWithoutBind,
                         ArrayRef<OMPClause *> Clauses,
-                        OpenMPBindClauseKind BindKind,
+                        OpenMPBindClauseKind &BindKind,
                         OpenMPDirectiveKind &Kind,
-                        OpenMPDirectiveKind &PrevMappedDirective);
+                        OpenMPDirectiveKind &PrevMappedDirective,
+                        SourceLocation StartLoc, SourceLocation EndLoc,
+                        const DeclarationNameInfo &DirName,
+                        OpenMPDirectiveKind CancelRegion);
 
 public:
   /// The declarator \p D defines a function in the scope \p S which is nested
@@ -12969,7 +12975,7 @@ class Sema final {
   QualType FindCompositeObjCPointerType(ExprResult &LHS, ExprResult &RHS,
                                         SourceLocation QuestionLoc);
 
-  bool DiagnoseConditionalForNull(Expr *LHSExpr, Expr *RHSExpr,
+  bool DiagnoseConditionalForNull(const Expr *LHSExpr, const Expr *RHSExpr,
                                   SourceLocation QuestionLoc);
 
   void DiagnoseAlwaysNonNullPointer(Expr *E,

diff --git a/clang/include/clang/Sema/TypoCorrection.h b/clang/include/clang/Sema/TypoCorrection.h
@@ -282,7 +282,7 @@ class CorrectionCandidateCallback {
 public:
   static const unsigned InvalidDistance = TypoCorrection::InvalidDistance;
 
-  explicit CorrectionCandidateCallback(IdentifierInfo *Typo = nullptr,
+  explicit CorrectionCandidateCallback(const IdentifierInfo *Typo = nullptr,
                                        NestedNameSpecifier *TypoNNS = nullptr)
       : Typo(Typo), TypoNNS(TypoNNS) {}
 
@@ -319,7 +319,7 @@ class CorrectionCandidateCallback {
   /// this method.
   virtual std::unique_ptr<CorrectionCandidateCallback> clone() = 0;
 
-  void setTypoName(IdentifierInfo *II) { Typo = II; }
+  void setTypoName(const IdentifierInfo *II) { Typo = II; }
   void setTypoNNS(NestedNameSpecifier *NNS) { TypoNNS = NNS; }
 
   // Flags for context-dependent keywords. WantFunctionLikeCasts is only
@@ -345,13 +345,13 @@ class CorrectionCandidateCallback {
            candidate.getCorrectionSpecifier() == TypoNNS;
   }
 
-  IdentifierInfo *Typo;
+  const IdentifierInfo *Typo;
   NestedNameSpecifier *TypoNNS;
 };
 
 class DefaultFilterCCC final : public CorrectionCandidateCallback {
 public:
-  explicit DefaultFilterCCC(IdentifierInfo *Typo = nullptr,
+  explicit DefaultFilterCCC(const IdentifierInfo *Typo = nullptr,
                             NestedNameSpecifier *TypoNNS = nullptr)
       : CorrectionCandidateCallback(Typo, TypoNNS) {}
 
@@ -365,6 +365,10 @@ class DefaultFilterCCC final : public CorrectionCandidateCallback {
 template <class C>
 class DeclFilterCCC final : public CorrectionCandidateCallback {
 public:
+  explicit DeclFilterCCC(const IdentifierInfo *Typo = nullptr,
+                         NestedNameSpecifier *TypoNNS = nullptr)
+      : CorrectionCandidateCallback(Typo, TypoNNS) {}
+
   bool ValidateCandidate(const TypoCorrection &candidate) override {
     return candidate.getCorrectionDeclAs<C>();
   }

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
@@ -1318,6 +1318,13 @@ void ASTContext::InitBuiltinTypes(const TargetInfo &Target,
     InitBuiltinType(OMPArrayShapingTy, BuiltinType::OMPArrayShaping);
     InitBuiltinType(OMPIteratorTy, BuiltinType::OMPIterator);
   }
+  // Placeholder type for OpenACC array sections.
+  if (LangOpts.OpenACC) {
+    // FIXME: Once we implement OpenACC array sections in Sema, this will either
+    // be combined with the OpenMP type, or given its own type. In the meantime,
+    // just use the OpenMP type so that parsing can work.
+    InitBuiltinType(OMPArraySectionTy, BuiltinType::OMPArraySection);
+  }
   if (LangOpts.MatrixTypes)
     InitBuiltinType(IncompleteMatrixIdxTy, BuiltinType::IncompleteMatrixIdx);
 

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
@@ -2034,23 +2034,25 @@ ASTNodeImporter::ImportDeclContext(DeclContext *FromDC, bool ForceImport) {
     return ToDCOrErr.takeError();
   }
 
-  DeclContext *ToDC = *ToDCOrErr;
-  // Remove all declarations, which may be in wrong order in the
-  // lexical DeclContext and then add them in the proper order.
-  for (auto *D : FromDC->decls()) {
-    if (!MightNeedReordering(D))
-      continue;
+  if (const auto *FromRD = dyn_cast<RecordDecl>(FromDC)) {
+    DeclContext *ToDC = *ToDCOrErr;
+    // Remove all declarations, which may be in wrong order in the
+    // lexical DeclContext and then add them in the proper order.
+    for (auto *D : FromRD->decls()) {
+      if (!MightNeedReordering(D))
+        continue;
 
-    assert(D && "DC contains a null decl");
-    if (Decl *ToD = Importer.GetAlreadyImportedOrNull(D)) {
-      // Remove only the decls which we successfully imported.
-      assert(ToDC == ToD->getLexicalDeclContext() && ToDC->containsDecl(ToD));
-      // Remove the decl from its wrong place in the linked list.
-      ToDC->removeDecl(ToD);
-      // Add the decl to the end of the linked list.
-      // This time it will be at the proper place because the enclosing for
-      // loop iterates in the original (good) order of the decls.
-      ToDC->addDeclInternal(ToD);
+      assert(D && "DC contains a null decl");
+      if (Decl *ToD = Importer.GetAlreadyImportedOrNull(D)) {
+        // Remove only the decls which we successfully imported.
+        assert(ToDC == ToD->getLexicalDeclContext() && ToDC->containsDecl(ToD));
+        // Remove the decl from its wrong place in the linked list.
+        ToDC->removeDecl(ToD);
+        // Add the decl to the end of the linked list.
+        // This time it will be at the proper place because the enclosing for
+        // loop iterates in the original (good) order of the decls.
+        ToDC->addDeclInternal(ToD);
+      }
     }
   }
 
@@ -5927,15 +5929,22 @@ ExpectedDecl ASTNodeImporter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
   if (ToD)
     return ToD;
 
-  bool IsFriendTemplate = D->getFriendObjectKind() != Decl::FOK_None;
-  bool IsDependentContext = DC != LexicalDC ? LexicalDC->isDependentContext()
-                                            : DC->isDependentContext();
-  bool DependentFriend = IsFriendTemplate && IsDependentContext;
+  // Should check if a declaration is friend in a dependent context.
+  // Such templates are not linked together in a declaration chain.
+  // The ASTImporter strategy is to map existing forward declarations to
+  // imported ones only if strictly necessary, otherwise import these as new
+  // forward declarations. In case of the "dependent friend" declarations, new
+  // declarations are created, but not linked in a declaration chain.
+  auto IsDependentFriend = [](ClassTemplateDecl *TD) {
+    return TD->getFriendObjectKind() != Decl::FOK_None &&
+           TD->getLexicalDeclContext()->isDependentContext();
+  };
+  bool DependentFriend = IsDependentFriend(D);
 
   ClassTemplateDecl *FoundByLookup = nullptr;
 
   // We may already have a template of the same name; try to find and match it.
-  if (!DependentFriend && !DC->isFunctionOrMethod()) {
+  if (!DC->isFunctionOrMethod()) {
     SmallVector<NamedDecl *, 4> ConflictingDecls;
     auto FoundDecls = Importer.findDeclsInToCtx(DC, Name);
     for (auto *FoundDecl : FoundDecls) {
@@ -5951,10 +5960,13 @@ ExpectedDecl ASTNodeImporter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
 
         // FIXME: sufficient conditon for 'IgnoreTemplateParmDepth'?
         bool IgnoreTemplateParmDepth =
-            FoundTemplate->getFriendObjectKind() != Decl::FOK_None &&
-            !D->specializations().empty();
+            (FoundTemplate->getFriendObjectKind() != Decl::FOK_None) !=
+            (D->getFriendObjectKind() != Decl::FOK_None);
         if (IsStructuralMatch(D, FoundTemplate, /*Complain=*/true,
                               IgnoreTemplateParmDepth)) {
+          if (DependentFriend || IsDependentFriend(FoundTemplate))
+            continue;
+
           ClassTemplateDecl *TemplateWithDef =
               getTemplateDefinition(FoundTemplate);
           if (D->isThisDeclarationADefinition() && TemplateWithDef)
@@ -9028,6 +9040,10 @@ class AttrImporter {
 public:
   AttrImporter(ASTImporter &I) : Importer(I), NImporter(I) {}
 
+  // Useful for accessing the imported attribute.
+  template <typename T> T *castAttrAs() { return cast<T>(ToAttr); }
+  template <typename T> const T *castAttrAs() const { return cast<T>(ToAttr); }
+
   // Create an "importer" for an attribute parameter.
   // Result of the 'value()' of that object is to be passed to the function
   // 'importAttr', in the order that is expected by the attribute class.
@@ -9241,6 +9257,15 @@ Expected<Attr *> ASTImporter::Import(const Attr *FromAttr) {
                   From->args_size());
     break;
   }
+  case attr::CountedBy: {
+    AI.cloneAttr(FromAttr);
+    const auto *CBA = cast<CountedByAttr>(FromAttr);
+    Expected<SourceRange> SR = Import(CBA->getCountedByFieldLoc()).get();
+    if (!SR)
+      return SR.takeError();
+    AI.castAttrAs<CountedByAttr>()->setCountedByFieldLoc(SR.get());
+    break;
+  }
 
   default: {
     // The default branch works for attributes that have no arguments to import.

diff --git a/clang/lib/AST/ASTStructuralEquivalence.cpp b/clang/lib/AST/ASTStructuralEquivalence.cpp
@@ -1463,8 +1463,9 @@ IsStructurallyEquivalentLambdas(StructuralEquivalenceContext &Context,
 }
 
 /// Determine if context of a class is equivalent.
-static bool IsRecordContextStructurallyEquivalent(RecordDecl *D1,
-                                                  RecordDecl *D2) {
+static bool
+IsRecordContextStructurallyEquivalent(StructuralEquivalenceContext &Context,
+                                      RecordDecl *D1, RecordDecl *D2) {
   // The context should be completely equal, including anonymous and inline
   // namespaces.
   // We compare objects as part of full translation units, not subtrees of
@@ -1491,6 +1492,12 @@ static bool IsRecordContextStructurallyEquivalent(RecordDecl *D1,
         return false;
     }
 
+    if (auto *D1Spec = dyn_cast<ClassTemplateSpecializationDecl>(DC1)) {
+      auto *D2Spec = dyn_cast<ClassTemplateSpecializationDecl>(DC2);
+      if (!IsStructurallyEquivalent(Context, D1Spec, D2Spec))
+        return false;
+    }
+
     DC1 = DC1->getParent()->getNonTransparentContext();
     DC2 = DC2->getParent()->getNonTransparentContext();
   }
@@ -1544,7 +1551,7 @@ static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
   // If the records occur in different context (namespace), these should be
   // different. This is specially important if the definition of one or both
   // records is missing.
-  if (!IsRecordContextStructurallyEquivalent(D1, D2))
+  if (!IsRecordContextStructurallyEquivalent(Context, D1, D2))
     return false;
 
   // If both declarations are class template specializations, we know

diff --git a/clang/lib/AST/ComputeDependence.cpp b/clang/lib/AST/ComputeDependence.cpp
@@ -603,6 +603,8 @@ ExprDependence clang::computeDependence(PredefinedExpr *E) {
 ExprDependence clang::computeDependence(CallExpr *E,
                                         llvm::ArrayRef<Expr *> PreArgs) {
   auto D = E->getCallee()->getDependence();
+  if (E->getType()->isDependentType())
+    D |= ExprDependence::Type;
   for (auto *A : llvm::ArrayRef(E->getArgs(), E->getNumArgs())) {
     if (A)
       D |= A->getDependence();

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
@@ -2835,7 +2835,7 @@ CharUnits VarDecl::getFlexibleArrayInitChars(const ASTContext &Ctx) const {
   if (!Ty || !Ty->getDecl()->hasFlexibleArrayMember())
     return CharUnits::Zero();
   auto *List = dyn_cast<InitListExpr>(getInit()->IgnoreParens());
-  if (!List)
+  if (!List || List->getNumInits() == 0)
     return CharUnits::Zero();
   const Expr *FlexibleInit = List->getInit(List->getNumInits() - 1);
   auto InitTy = Ctx.getAsConstantArrayType(FlexibleInit->getType());