Index: libcxxabi/src/demangle/ItaniumDemangle.h
===================================================================
--- libcxxabi/src/demangle/ItaniumDemangle.h
+++ libcxxabi/src/demangle/ItaniumDemangle.h
@@ -2821,7 +2821,8 @@
 
   if (consumeIf('C')) {
     bool IsInherited = consumeIf('I');
-    if (look() != '1' && look() != '2' && look() != '3' && look() != '5')
+    if (look() != '1' && look() != '2' && look() != '3' && look() != '4' &&
+        look() != '5')
       return nullptr;
     int Variant = look() - '0';
     ++First;
@@ -2830,15 +2831,15 @@
       if (getDerived().parseName(State) == nullptr)
         return nullptr;
     }
-    return make<CtorDtorName>(SoFar, false, Variant);
+    return make<CtorDtorName>(SoFar, /*IsDtor=*/false, Variant);
   }
 
-  if (look() == 'D' &&
-      (look(1) == '0' || look(1) == '1' || look(1) == '2' || look(1) == '5')) {
+  if (look() == 'D' && (look(1) == '0' || look(1) == '1' || look(1) == '2' ||
+                        look(1) == '4' || look(1) == '5')) {
     int Variant = look(1) - '0';
     First += 2;
     if (State) State->CtorDtorConversion = true;
-    return make<CtorDtorName>(SoFar, true, Variant);
+    return make<CtorDtorName>(SoFar, /*IsDtor=*/true, Variant);
   }
 
   return nullptr;
Index: libcxxabi/test/test_demangle.pass.cpp
===================================================================
--- libcxxabi/test/test_demangle.pass.cpp
+++ libcxxabi/test/test_demangle.pass.cpp
@@ -765,10 +765,16 @@
     {"_ZNK5clang14ASTMergeAction13hasPCHSupportEv", "clang::ASTMergeAction::hasPCHSupport() const"},
     {"_ZNK5clang14ASTMergeAction17hasASTFileSupportEv", "clang::ASTMergeAction::hasASTFileSupport() const"},
     {"_ZNK5clang14ASTMergeAction24hasCodeCompletionSupportEv", "clang::ASTMergeAction::hasCodeCompletionSupport() const"},
+    {"_ZN5clang7ASTUnitC0Eb", "clang::ASTUnit::ASTUnit(bool)"},
     {"_ZN5clang7ASTUnitC1Eb", "clang::ASTUnit::ASTUnit(bool)"},
     {"_ZN5clang7ASTUnitC2Eb", "clang::ASTUnit::ASTUnit(bool)"},
+    {"_ZN5clang7ASTUnitC4Eb", "clang::ASTUnit::ASTUnit(bool)"},
+    {"_ZN5clang7ASTUnitC5Eb", "clang::ASTUnit::ASTUnit(bool)"},
+    {"_ZN5clang7ASTUnitD0Ev", "clang::ASTUnit::~ASTUnit()"},
     {"_ZN5clang7ASTUnitD1Ev", "clang::ASTUnit::~ASTUnit()"},
     {"_ZN5clang7ASTUnitD2Ev", "clang::ASTUnit::~ASTUnit()"},
+    {"_ZN5clang7ASTUnitD4Ev", "clang::ASTUnit::~ASTUnit()"},
+    {"_ZN5clang7ASTUnitD5Ev", "clang::ASTUnit::~ASTUnit()"},
     {"_ZN5clang7ASTUnit19CleanTemporaryFilesEv", "clang::ASTUnit::CleanTemporaryFiles()"},
     {"_ZN5clang7ASTUnit28ClearCachedCompletionResultsEv", "clang::ASTUnit::ClearCachedCompletionResults()"},
     {"_ZN5clang7ASTUnit26CacheCodeCompletionResultsEv", "clang::ASTUnit::CacheCodeCompletionResults()"},
Index: llvm/include/llvm/Demangle/ItaniumDemangle.h
===================================================================
--- llvm/include/llvm/Demangle/ItaniumDemangle.h
+++ llvm/include/llvm/Demangle/ItaniumDemangle.h
@@ -2821,7 +2821,8 @@
 
   if (consumeIf('C')) {
     bool IsInherited = consumeIf('I');
-    if (look() != '1' && look() != '2' && look() != '3' && look() != '5')
+    if (look() != '1' && look() != '2' && look() != '3' && look() != '4' &&
+        look() != '5')
       return nullptr;
     int Variant = look() - '0';
     ++First;
@@ -2830,15 +2831,15 @@
       if (getDerived().parseName(State) == nullptr)
         return nullptr;
     }
-    return make<CtorDtorName>(SoFar, false, Variant);
+    return make<CtorDtorName>(SoFar, /*IsDtor=*/false, Variant);
   }
 
-  if (look() == 'D' &&
-      (look(1) == '0' || look(1) == '1' || look(1) == '2' || look(1) == '5')) {
+  if (look() == 'D' && (look(1) == '0' || look(1) == '1' || look(1) == '2' ||
+                        look(1) == '4' || look(1) == '5')) {
     int Variant = look(1) - '0';
     First += 2;
     if (State) State->CtorDtorConversion = true;
-    return make<CtorDtorName>(SoFar, true, Variant);
+    return make<CtorDtorName>(SoFar, /*IsDtor=*/true, Variant);
   }
 
   return nullptr;