diff --git a/clang/lib/Basic/Diagnostic.cpp b/clang/lib/Basic/Diagnostic.cpp
index 8ecbd3c5a2cc4..2dec26ecacf26 100644
--- a/clang/lib/Basic/Diagnostic.cpp
+++ b/clang/lib/Basic/Diagnostic.cpp
@@ -525,7 +525,8 @@ std::unique_ptr<WarningsSpecialCaseList>
 WarningsSpecialCaseList::create(const llvm::MemoryBuffer &Input,
                                 std::string &Err) {
   auto WarningSuppressionList = std::make_unique<WarningsSpecialCaseList>();
-  if (!WarningSuppressionList->createInternal(&Input, Err))
+  if (!WarningSuppressionList->createInternal(&Input, Err,
+                                              /*OrderBySize=*/true))
     return nullptr;
   return WarningSuppressionList;
 }
diff --git a/llvm/include/llvm/Support/SpecialCaseList.h b/llvm/include/llvm/Support/SpecialCaseList.h
index 477987c576965..ead765562504d 100644
--- a/llvm/include/llvm/Support/SpecialCaseList.h
+++ b/llvm/include/llvm/Support/SpecialCaseList.h
@@ -115,7 +115,8 @@ class SpecialCaseList {
   // classes.
   LLVM_ABI bool createInternal(const std::vector<std::string> &Paths,
                                vfs::FileSystem &VFS, std::string &Error);
-  LLVM_ABI bool createInternal(const MemoryBuffer *MB, std::string &Error);
+  LLVM_ABI bool createInternal(const MemoryBuffer *MB, std::string &Error,
+                               bool OrderBySize = false);
 
   SpecialCaseList() = default;
   SpecialCaseList(SpecialCaseList const &) = delete;
@@ -126,6 +127,8 @@ class SpecialCaseList {
   class RegexMatcher {
   public:
     LLVM_ABI Error insert(StringRef Pattern, unsigned LineNumber);
+    LLVM_ABI void preprocess(bool BySize);
+
     LLVM_ABI void
     match(StringRef Query,
           llvm::function_ref<void(StringRef Rule, unsigned LineNo)> Cb) const;
@@ -144,6 +147,8 @@ class SpecialCaseList {
   class GlobMatcher {
   public:
     LLVM_ABI Error insert(StringRef Pattern, unsigned LineNumber);
+    LLVM_ABI void preprocess(bool BySize);
+
     LLVM_ABI void
     match(StringRef Query,
           llvm::function_ref<void(StringRef Rule, unsigned LineNo)> Cb) const;
@@ -165,6 +170,7 @@ class SpecialCaseList {
     LLVM_ABI Matcher(bool UseGlobs, bool RemoveDotSlash);
 
     LLVM_ABI Error insert(StringRef Pattern, unsigned LineNumber);
+    LLVM_ABI void preprocess(bool BySize);
 
     LLVM_ABI void
     match(StringRef Query,
@@ -206,6 +212,8 @@ class SpecialCaseList {
                                        StringRef Category) const;
 
   private:
+    friend class SpecialCaseList;
+    LLVM_ABI void preprocess(bool OrderBySize);
     LLVM_ABI const SpecialCaseList::Matcher *
     findMatcher(StringRef Prefix, StringRef Category) const;
   };
@@ -222,7 +230,7 @@ class SpecialCaseList {
 
   /// Parses just-constructed SpecialCaseList entries from a memory buffer.
   LLVM_ABI bool parse(unsigned FileIdx, const MemoryBuffer *MB,
-                      std::string &Error);
+                      std::string &Error, bool OrderBySize);
 };
 
 } // namespace llvm
diff --git a/llvm/lib/Support/SpecialCaseList.cpp b/llvm/lib/Support/SpecialCaseList.cpp
index 80fd48558fe67..549c4183298d8 100644
--- a/llvm/lib/Support/SpecialCaseList.cpp
+++ b/llvm/lib/Support/SpecialCaseList.cpp
@@ -55,12 +55,20 @@ Error SpecialCaseList::RegexMatcher::insert(StringRef Pattern,
   return Error::success();
 }
 
+void SpecialCaseList::RegexMatcher::preprocess(bool BySize) {
+  if (BySize) {
+    llvm::stable_sort(RegExes, [](const Reg &A, const Reg &B) {
+      return A.Name.size() < B.Name.size();
+    });
+  }
+}
+
 void SpecialCaseList::RegexMatcher::match(
     StringRef Query,
     llvm::function_ref<void(StringRef Rule, unsigned LineNo)> Cb) const {
   for (const auto &R : reverse(RegExes))
     if (R.Rg.match(Query))
-      Cb(R.Name, R.LineNo);
+      return Cb(R.Name, R.LineNo);
 }
 
 Error SpecialCaseList::GlobMatcher::insert(StringRef Pattern,
@@ -75,12 +83,20 @@ Error SpecialCaseList::GlobMatcher::insert(StringRef Pattern,
   return Error::success();
 }
 
+void SpecialCaseList::GlobMatcher::preprocess(bool BySize) {
+  if (BySize) {
+    llvm::stable_sort(Globs, [](const Glob &A, const Glob &B) {
+      return A.Name.size() < B.Name.size();
+    });
+  }
+}
+
 void SpecialCaseList::GlobMatcher::match(
     StringRef Query,
     llvm::function_ref<void(StringRef Rule, unsigned LineNo)> Cb) const {
   for (const auto &G : reverse(Globs))
     if (G.Pattern.match(Query))
-      Cb(G.Name, G.LineNo);
+      return Cb(G.Name, G.LineNo);
 }
 
 SpecialCaseList::Matcher::Matcher(bool UseGlobs, bool RemoveDotSlash)
@@ -91,6 +107,14 @@ SpecialCaseList::Matcher::Matcher(bool UseGlobs, bool RemoveDotSlash)
     M.emplace<RegexMatcher>();
 }
 
+Error SpecialCaseList::Matcher::insert(StringRef Pattern, unsigned LineNumber) {
+  return std::visit([&](auto &V) { return V.insert(Pattern, LineNumber); }, M);
+}
+
+LLVM_ABI void SpecialCaseList::Matcher::preprocess(bool BySize) {
+  return std::visit([&](auto &V) { return V.preprocess(BySize); }, M);
+}
+
 void SpecialCaseList::Matcher::match(
     StringRef Query,
     llvm::function_ref<void(StringRef Rule, unsigned LineNo)> Cb) const {
@@ -99,10 +123,6 @@ void SpecialCaseList::Matcher::match(
   return std::visit([&](auto &V) { return V.match(Query, Cb); }, M);
 }
 
-Error SpecialCaseList::Matcher::insert(StringRef Pattern, unsigned LineNumber) {
-  return std::visit([&](auto &V) { return V.insert(Pattern, LineNumber); }, M);
-}
-
 // TODO: Refactor this to return Expected<...>
 std::unique_ptr<SpecialCaseList>
 SpecialCaseList::create(const std::vector<std::string> &Paths,
@@ -141,7 +161,7 @@ bool SpecialCaseList::createInternal(const std::vector<std::string> &Paths,
       return false;
     }
     std::string ParseError;
-    if (!parse(i, FileOrErr.get().get(), ParseError)) {
+    if (!parse(i, FileOrErr.get().get(), ParseError, /*OrderBySize=*/false)) {
       Error = (Twine("error parsing file '") + Path + "': " + ParseError).str();
       return false;
     }
@@ -149,9 +169,9 @@ bool SpecialCaseList::createInternal(const std::vector<std::string> &Paths,
   return true;
 }
 
-bool SpecialCaseList::createInternal(const MemoryBuffer *MB,
-                                     std::string &Error) {
-  if (!parse(0, MB, Error))
+bool SpecialCaseList::createInternal(const MemoryBuffer *MB, std::string &Error,
+                                     bool OrderBySize) {
+  if (!parse(0, MB, Error, OrderBySize))
     return false;
   return true;
 }
@@ -174,7 +194,7 @@ SpecialCaseList::addSection(StringRef SectionStr, unsigned FileNo,
 }
 
 bool SpecialCaseList::parse(unsigned FileIdx, const MemoryBuffer *MB,
-                            std::string &Error) {
+                            std::string &Error, bool OrderBySize) {
   unsigned long long Version = 2;
 
   StringRef Header = MB->getBuffer();
@@ -246,6 +266,10 @@ bool SpecialCaseList::parse(unsigned FileIdx, const MemoryBuffer *MB,
       return false;
     }
   }
+
+  for (Section &S : Sections)
+    S.preprocess(OrderBySize);
+
   return true;
 }
 
@@ -283,6 +307,13 @@ SpecialCaseList::Section::findMatcher(StringRef Prefix,
   return &II->second;
 }
 
+LLVM_ABI void SpecialCaseList::Section::preprocess(bool OrderBySize) {
+  SectionMatcher.preprocess(false);
+  for (auto &[K1, E] : Entries)
+    for (auto &[K2, M] : E)
+      M.preprocess(OrderBySize);
+}
+
 unsigned SpecialCaseList::Section::getLastMatch(StringRef Prefix,
                                                 StringRef Query,
                                                 StringRef Category) const {