Index: include/clang/ASTMatchers/ASTMatchers.h
===================================================================
--- include/clang/ASTMatchers/ASTMatchers.h
+++ include/clang/ASTMatchers/ASTMatchers.h
@@ -267,8 +267,8 @@
   }
 
   auto Filename = FileEntry->getName();
-  llvm::Regex RE(RegExp);
-  return RE.match(Filename);
+  auto RE = llvm::Regex::compile(RegExp);
+  return RE && RE->match(Filename);
 }
 
 /// \brief Matches declarations.
@@ -2178,8 +2178,8 @@
 AST_MATCHER_P(NamedDecl, matchesName, std::string, RegExp) {
   assert(!RegExp.empty());
   std::string FullNameString = "::" + Node.getQualifiedNameAsString();
-  llvm::Regex RE(RegExp);
-  return RE.match(FullNameString);
+  auto RE = llvm::Regex::compile(RegExp);
+  return RE && RE->match(FullNameString);
 }
 
 /// \brief Matches overloaded operator names.
@@ -2550,8 +2550,8 @@
 AST_MATCHER_P(ObjCMessageExpr, matchesSelector, std::string, RegExp) {
   assert(!RegExp.empty());
   std::string SelectorString = Node.getSelector().getAsString();
-  llvm::Regex RE(RegExp);
-  return RE.match(SelectorString);
+  auto RE = llvm::Regex::compile(RegExp);
+  return RE && RE->match(SelectorString);
 }
 
 /// \brief Matches when the selector is the empty selector
Index: lib/Driver/Multilib.cpp
===================================================================
--- lib/Driver/Multilib.cpp
+++ lib/Driver/Multilib.cpp
@@ -214,16 +214,15 @@
 }
 
 MultilibSet &MultilibSet::FilterOut(const char *Regex) {
-  llvm::Regex R(Regex);
+  auto R = llvm::Regex::compile(Regex);
+  if (!R) {
 #ifndef NDEBUG
-  std::string Error;
-  if (!R.isValid(Error)) {
-    llvm::errs() << Error;
+    llvm::errs() << R.takeError();
+#endif
     llvm_unreachable("Invalid regex!");
   }
-#endif
 
-  filterInPlace([&R](const Multilib &M) { return R.match(M.gccSuffix()); },
+  filterInPlace([&R](const Multilib &M) { return R->match(M.gccSuffix()); },
                 Multilibs);
   return *this;
 }
Index: lib/Format/ContinuationIndenter.cpp
===================================================================
--- lib/Format/ContinuationIndenter.cpp
+++ lib/Format/ContinuationIndenter.cpp
@@ -69,8 +69,11 @@
                                            bool BinPackInconclusiveFunctions)
     : Style(Style), Keywords(Keywords), SourceMgr(SourceMgr),
       Whitespaces(Whitespaces), Encoding(Encoding),
-      BinPackInconclusiveFunctions(BinPackInconclusiveFunctions),
-      CommentPragmasRegex(Style.CommentPragmas) {}
+      BinPackInconclusiveFunctions(BinPackInconclusiveFunctions) {
+  if (auto RegexOrError = llvm::Regex::compile(Style.CommentPragmas)) {
+    CommentPragmasRegex = std::move(*RegexOrError);
+  }
+}
 
 LineState ContinuationIndenter::getInitialState(unsigned FirstIndent,
                                                 const AnnotatedLine *Line,
Index: lib/Format/Format.cpp
===================================================================
--- lib/Format/Format.cpp
+++ lib/Format/Format.cpp
@@ -1336,8 +1336,11 @@
   IncludeCategoryManager(const FormatStyle &Style, StringRef FileName)
       : Style(Style), FileName(FileName) {
     FileStem = llvm::sys::path::stem(FileName);
-    for (const auto &Category : Style.IncludeCategories)
-      CategoryRegexs.emplace_back(Category.Regex);
+    for (const auto &Category : Style.IncludeCategories) {
+      if (auto RegexOrError = llvm::Regex::compile(Category.Regex)) {
+        CategoryRegexs.emplace_back(std::move(*RegexOrError));
+      }
+    }
     IsMainFile = FileName.endswith(".c") || FileName.endswith(".cc") ||
                  FileName.endswith(".cpp") || FileName.endswith(".c++") ||
                  FileName.endswith(".cxx") || FileName.endswith(".m") ||
@@ -1366,9 +1369,9 @@
     StringRef HeaderStem =
         llvm::sys::path::stem(IncludeName.drop_front(1).drop_back(1));
     if (FileStem.startswith(HeaderStem)) {
-      llvm::Regex MainIncludeRegex(
+      auto MainIncludeRegex = llvm::Regex::compile(
           (HeaderStem + Style.IncludeIsMainRegex).str());
-      if (MainIncludeRegex.match(FileStem))
+      if (MainIncludeRegex && MainIncludeRegex->match(FileStem))
         return true;
     }
     return false;
@@ -1393,7 +1396,7 @@
                                       unsigned *Cursor) {
   unsigned Prev = 0;
   unsigned SearchFrom = 0;
-  llvm::Regex IncludeRegex(IncludeRegexPattern);
+  auto IncludeRegex = llvm::Regex::compile(IncludeRegexPattern);
   SmallVector<StringRef, 4> Matches;
   SmallVector<IncludeDirective, 16> IncludesInBlock;
 
@@ -1421,7 +1424,7 @@
       FormattingOff = false;
 
     if (!FormattingOff && !Line.endswith("\\")) {
-      if (IncludeRegex.match(Line, &Matches)) {
+      if (IncludeRegex && IncludeRegex->match(Line, &Matches)) {
         StringRef IncludeName = Matches[2];
         int Category = Categories.getIncludePriority(
             IncludeName,
@@ -1506,8 +1509,9 @@
 namespace {
 
 inline bool isHeaderInsertion(const tooling::Replacement &Replace) {
+  auto RegexOrError = llvm::Regex::compile(IncludeRegexPattern);
   return Replace.getOffset() == UINT_MAX && Replace.getLength() == 0 &&
-         llvm::Regex(IncludeRegexPattern).match(Replace.getReplacementText());
+      RegexOrError && RegexOrError->match(Replace.getReplacementText());
 }
 
 inline bool isHeaderDeletion(const tooling::Replacement &Replace) {
@@ -1658,8 +1662,7 @@
   if (HeaderInsertions.empty() && HeadersToDelete.empty())
     return Replaces;
 
-  llvm::Regex IncludeRegex(IncludeRegexPattern);
-  llvm::Regex DefineRegex(R"(^[\t\ ]*#[\t\ ]*define[\t\ ]*[^\\]*$)");
+  auto IncludeRegex = llvm::Regex::compile(IncludeRegexPattern);
   SmallVector<StringRef, 4> Matches;
 
   StringRef FileName = Replaces.begin()->getFilePath();
@@ -1686,7 +1689,7 @@
   std::set<StringRef> ExistingIncludes;
   for (auto Line : Lines) {
     NextLineOffset = std::min(Code.size(), Offset + Line.size() + 1);
-    if (IncludeRegex.match(Line, &Matches)) {
+    if (IncludeRegex && IncludeRegex->match(Line, &Matches)) {
       // The header name with quotes or angle brackets.
       StringRef IncludeName = Matches[2];
       ExistingIncludes.insert(IncludeName);
@@ -1737,7 +1740,8 @@
   bool NeedNewLineAtEnd = !Code.empty() && Code.back() != '\n';
   for (const auto &R : HeaderInsertions) {
     auto IncludeDirective = R.getReplacementText();
-    bool Matched = IncludeRegex.match(IncludeDirective, &Matches);
+    bool Matched =
+        IncludeRegex && IncludeRegex->match(IncludeDirective, &Matches);
     assert(Matched && "Header insertion replacement must have replacement text "
                       "'#include ...'");
     (void)Matched;
Index: lib/Format/FormatTokenLexer.cpp
===================================================================
--- lib/Format/FormatTokenLexer.cpp
+++ lib/Format/FormatTokenLexer.cpp
@@ -30,8 +30,13 @@
       Column(0), TrailingWhitespace(0), SourceMgr(SourceMgr), ID(ID),
       Style(Style), IdentTable(getFormattingLangOpts(Style)),
       Keywords(IdentTable), Encoding(Encoding), FirstInLineIndex(0),
-      FormattingDisabled(false), MacroBlockBeginRegex(Style.MacroBlockBegin),
-      MacroBlockEndRegex(Style.MacroBlockEnd) {
+      FormattingDisabled(false) {
+  if (auto RegexOrError = llvm::Regex::compile(Style.MacroBlockBegin)) {
+    MacroBlockBeginRegex = std::move(*RegexOrError);
+  }
+  if (auto RegexOrError = llvm::Regex::compile(Style.MacroBlockEnd)) {
+    MacroBlockEndRegex = std::move(*RegexOrError);
+  }
   Lex.reset(new Lexer(ID, SourceMgr.getBuffer(ID), SourceMgr,
                       getFormattingLangOpts(Style)));
   Lex->SetKeepWhitespaceMode(true);
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -338,13 +338,13 @@
                                 Arg *RpassArg) {
   StringRef Val = RpassArg->getValue();
   std::string RegexError;
-  std::shared_ptr<llvm::Regex> Pattern = std::make_shared<llvm::Regex>(Val);
-  if (!Pattern->isValid(RegexError)) {
+  auto RegexOrError = llvm::Regex::compile(Val);
+  if (!RegexOrError) {
     Diags.Report(diag::err_drv_optimization_remark_pattern)
-        << RegexError << RpassArg->getAsString(Args);
-    Pattern.reset();
+        << toString(RegexOrError.takeError()) << RpassArg->getAsString(Args);
+    return nullptr;
   }
-  return Pattern;
+  return std::make_shared<llvm::Regex>(std::move(*RegexOrError));
 }
 
 static bool parseDiagnosticLevelMask(StringRef FlagName,
Index: lib/Frontend/VerifyDiagnosticConsumer.cpp
===================================================================
--- lib/Frontend/VerifyDiagnosticConsumer.cpp
+++ lib/Frontend/VerifyDiagnosticConsumer.cpp
@@ -184,18 +184,21 @@
                  bool MatchAnyLine, StringRef Text, unsigned Min, unsigned Max,
                  StringRef RegexStr)
     : Directive(DirectiveLoc, DiagnosticLoc, MatchAnyLine, Text, Min, Max),
-      Regex(RegexStr) { }
+      Regex(llvm::Regex::compile(RegexStr)) { }
 
   bool isValid(std::string &Error) override {
-    return Regex.isValid(Error);
+    if (Regex)
+      return true;
+    Error = toString(Regex.takeError());
+    return false;
   }
 
   bool match(StringRef S) override {
-    return Regex.match(S);
+    return Regex && Regex->match(S);
   }
 
 private:
-  llvm::Regex Regex;
+  llvm::Expected<llvm::Regex> Regex;
 };
 
 class ParseHelper
Index: tools/driver/driver.cpp
===================================================================
--- tools/driver/driver.cpp
+++ tools/driver/driver.cpp
@@ -120,7 +120,8 @@
       // Ignore end-of-line response file markers
       if (Args[i] == nullptr)
         continue;
-      std::string Repl = llvm::Regex(MatchPattern).sub(ReplPattern, Args[i]);
+      auto RE = llvm::Regex::compile(MatchPattern);
+      std::string Repl = RE ? RE->sub(ReplPattern, Args[i]) : Args[i];
 
       if (Repl != Args[i]) {
         OS << "### Replacing '" << Args[i] << "' with '" << Repl << "'\n";