diff --git a/clang/include/clang/AST/OpenMPClause.h b/clang/include/clang/AST/OpenMPClause.h
--- a/clang/include/clang/AST/OpenMPClause.h
+++ b/clang/include/clang/AST/OpenMPClause.h
@@ -866,7 +866,7 @@
   SourceLocation LParenLoc;
 
   /// A kind of the 'default' clause.
-  OpenMPDefaultClauseKind Kind = OMPC_DEFAULT_unknown;
+  llvm::omp::DefaultKind Kind = llvm::omp::OMP_DEFAULT_unknown;
 
   /// Start location of the kind in source code.
   SourceLocation KindKwLoc;
@@ -874,7 +874,7 @@
   /// Set kind of the clauses.
   ///
   /// \param K Argument of clause.
-  void setDefaultKind(OpenMPDefaultClauseKind K) { Kind = K; }
+  void setDefaultKind(llvm::omp::DefaultKind K) { Kind = K; }
 
   /// Set argument location.
   ///
@@ -889,7 +889,7 @@
   /// \param StartLoc Starting location of the clause.
   /// \param LParenLoc Location of '('.
   /// \param EndLoc Ending location of the clause.
-  OMPDefaultClause(OpenMPDefaultClauseKind A, SourceLocation ALoc,
+  OMPDefaultClause(llvm::omp::DefaultKind A, SourceLocation ALoc,
                    SourceLocation StartLoc, SourceLocation LParenLoc,
                    SourceLocation EndLoc)
       : OMPClause(OMPC_default, StartLoc, EndLoc), LParenLoc(LParenLoc),
@@ -906,7 +906,7 @@
   SourceLocation getLParenLoc() const { return LParenLoc; }
 
   /// Returns kind of the clause.
-  OpenMPDefaultClauseKind getDefaultKind() const { return Kind; }
+  llvm::omp::DefaultKind getDefaultKind() const { return Kind; }
 
   /// Returns location of clause kind.
   SourceLocation getDefaultKindKwLoc() const { return KindKwLoc; }
diff --git a/clang/include/clang/ASTMatchers/ASTMatchers.h b/clang/include/clang/ASTMatchers/ASTMatchers.h
--- a/clang/include/clang/ASTMatchers/ASTMatchers.h
+++ b/clang/include/clang/ASTMatchers/ASTMatchers.h
@@ -7056,7 +7056,7 @@
 ///
 /// ``ompDefaultClause(isNoneKind())`` matches only ``default(none)``.
 AST_MATCHER(OMPDefaultClause, isNoneKind) {
-  return Node.getDefaultKind() == OMPC_DEFAULT_none;
+  return Node.getDefaultKind() == llvm::omp::OMP_DEFAULT_none;
 }
 
 /// Matches if the OpenMP ``default`` clause has ``shared`` kind specified.
@@ -7071,7 +7071,7 @@
 ///
 /// ``ompDefaultClause(isSharedKind())`` matches only ``default(shared)``.
 AST_MATCHER(OMPDefaultClause, isSharedKind) {
-  return Node.getDefaultKind() == OMPC_DEFAULT_shared;
+  return Node.getDefaultKind() == llvm::omp::OMP_DEFAULT_shared;
 }
 
 /// Matches if the OpenMP directive is allowed to contain the specified OpenMP
diff --git a/clang/include/clang/Basic/OpenMPKinds.h b/clang/include/clang/Basic/OpenMPKinds.h
--- a/clang/include/clang/Basic/OpenMPKinds.h
+++ b/clang/include/clang/Basic/OpenMPKinds.h
@@ -73,14 +73,6 @@
   OMPC_unknown
 };
 
-/// OpenMP attributes for 'default' clause.
-enum OpenMPDefaultClauseKind {
-#define OPENMP_DEFAULT_KIND(Name) \
-  OMPC_DEFAULT_##Name,
-#include "clang/Basic/OpenMPKinds.def"
-  OMPC_DEFAULT_unknown
-};
-
 /// OpenMP attributes for 'schedule' clause.
 enum OpenMPScheduleClauseKind {
 #define OPENMP_SCHEDULE_KIND(Name) \
diff --git a/clang/include/clang/Basic/OpenMPKinds.def b/clang/include/clang/Basic/OpenMPKinds.def
--- a/clang/include/clang/Basic/OpenMPKinds.def
+++ b/clang/include/clang/Basic/OpenMPKinds.def
@@ -107,9 +107,6 @@
 #ifndef OPENMP_DISTRIBUTE_CLAUSE
 #define OPENMP_DISTRIBUTE_CLAUSE(Name)
 #endif
-#ifndef OPENMP_DEFAULT_KIND
-#  define OPENMP_DEFAULT_KIND(Name)
-#endif
 #ifndef OPENMP_SCHEDULE_KIND
 #define OPENMP_SCHEDULE_KIND(Name)
 #endif
@@ -365,10 +362,6 @@
 // Clauses allowed for OpenMP directive 'cancel'.
 OPENMP_CANCEL_CLAUSE(if)
 
-// Static attributes for 'default' clause.
-OPENMP_DEFAULT_KIND(none)
-OPENMP_DEFAULT_KIND(shared)
-
 // Static attributes for 'schedule' clause.
 OPENMP_SCHEDULE_KIND(static)
 OPENMP_SCHEDULE_KIND(dynamic)
@@ -1118,7 +1111,6 @@
 #undef OPENMP_DEPEND_KIND
 #undef OPENMP_SCHEDULE_MODIFIER
 #undef OPENMP_SCHEDULE_KIND
-#undef OPENMP_DEFAULT_KIND
 #undef OPENMP_CLAUSE
 #undef OPENMP_CRITICAL_CLAUSE
 #undef OPENMP_ORDERED_CLAUSE
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -10272,7 +10272,7 @@
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc);
   /// Called on well-formed 'default' clause.
-  OMPClause *ActOnOpenMPDefaultClause(OpenMPDefaultClauseKind Kind,
+  OMPClause *ActOnOpenMPDefaultClause(llvm::omp::DefaultKind Kind,
                                       SourceLocation KindLoc,
                                       SourceLocation StartLoc,
                                       SourceLocation LParenLoc,
diff --git a/clang/lib/AST/OpenMPClause.cpp b/clang/lib/AST/OpenMPClause.cpp
--- a/clang/lib/AST/OpenMPClause.cpp
+++ b/clang/lib/AST/OpenMPClause.cpp
@@ -1244,7 +1244,8 @@
 
 void OMPClausePrinter::VisitOMPDefaultClause(OMPDefaultClause *Node) {
   OS << "default("
-     << getOpenMPSimpleClauseTypeName(OMPC_default, Node->getDefaultKind())
+     << getOpenMPSimpleClauseTypeName(OMPC_default,
+                                      unsigned(Node->getDefaultKind()))
      << ")";
 }
 
diff --git a/clang/lib/Basic/OpenMPKinds.cpp b/clang/lib/Basic/OpenMPKinds.cpp
--- a/clang/lib/Basic/OpenMPKinds.cpp
+++ b/clang/lib/Basic/OpenMPKinds.cpp
@@ -104,10 +104,10 @@
                                           StringRef Str) {
   switch (Kind) {
   case OMPC_default:
-    return llvm::StringSwitch<OpenMPDefaultClauseKind>(Str)
-#define OPENMP_DEFAULT_KIND(Name) .Case(#Name, OMPC_DEFAULT_##Name)
-#include "clang/Basic/OpenMPKinds.def"
-        .Default(OMPC_DEFAULT_unknown);
+    return llvm::StringSwitch<unsigned>(Str)
+#define OMP_DEFAULT_KIND(Enum, Name, Value) .Case(Name, Value)
+#include "llvm/Frontend/OpenMP/OMPKinds.def"
+        .Default(unsigned(llvm::omp::OMP_DEFAULT_unknown));
   case OMPC_proc_bind:
     return llvm::StringSwitch<unsigned>(Str)
 #define OMP_PROC_BIND_KIND(Enum, Name, Value) .Case(Name, Value)
@@ -247,12 +247,10 @@
   switch (Kind) {
   case OMPC_default:
     switch (Type) {
-    case OMPC_DEFAULT_unknown:
-      return "unknown";
-#define OPENMP_DEFAULT_KIND(Name)                                              \
-  case OMPC_DEFAULT_##Name:                                                    \
-    return #Name;
-#include "clang/Basic/OpenMPKinds.def"
+#define OMP_DEFAULT_KIND(Enum, Name, Value)                                    \
+  case Value:                                                                  \
+    return Name;
+#include "llvm/Frontend/OpenMP/OMPKinds.def"
     }
     llvm_unreachable("Invalid OpenMP 'default' clause type");
   case OMPC_proc_bind:
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -12034,9 +12034,8 @@
   OMPClause *Res = nullptr;
   switch (Kind) {
   case OMPC_default:
-    Res =
-        ActOnOpenMPDefaultClause(static_cast<OpenMPDefaultClauseKind>(Argument),
-                                 ArgumentLoc, StartLoc, LParenLoc, EndLoc);
+    Res = ActOnOpenMPDefaultClause(static_cast<DefaultKind>(Argument),
+                                   ArgumentLoc, StartLoc, LParenLoc, EndLoc);
     break;
   case OMPC_proc_bind:
     Res = ActOnOpenMPProcBindClause(static_cast<ProcBindKind>(Argument),
@@ -12139,31 +12138,24 @@
   return std::string(Out.str());
 }
 
-OMPClause *Sema::ActOnOpenMPDefaultClause(OpenMPDefaultClauseKind Kind,
+OMPClause *Sema::ActOnOpenMPDefaultClause(DefaultKind Kind,
                                           SourceLocation KindKwLoc,
                                           SourceLocation StartLoc,
                                           SourceLocation LParenLoc,
                                           SourceLocation EndLoc) {
-  if (Kind == OMPC_DEFAULT_unknown) {
-    static_assert(OMPC_DEFAULT_unknown > 0,
-                  "OMPC_DEFAULT_unknown not greater than 0");
+  if (Kind == OMP_DEFAULT_unknown) {
     Diag(KindKwLoc, diag::err_omp_unexpected_clause_value)
-        << getListOfPossibleValues(OMPC_default, /*First=*/0,
-                                   /*Last=*/OMPC_DEFAULT_unknown)
+        << getListOfPossibleValues(OMPC_default,
+                                   /*First=*/unsigned(OMP_DEFAULT_none),
+                                   /*Last=*/4)
         << getOpenMPClauseName(OMPC_default);
     return nullptr;
   }
-  switch (Kind) {
-  case OMPC_DEFAULT_none:
+  if (Kind == OMP_DEFAULT_none)
     DSAStack->setDefaultDSANone(KindKwLoc);
-    break;
-  case OMPC_DEFAULT_shared:
+  else if (Kind == OMP_DEFAULT_shared)
     DSAStack->setDefaultDSAShared(KindKwLoc);
-    break;
-  case OMPC_DEFAULT_unknown:
-    llvm_unreachable("Clause kind is not allowed.");
-    break;
-  }
+
   return new (Context)
       OMPDefaultClause(Kind, KindKwLoc, StartLoc, LParenLoc, EndLoc);
 }
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -1602,8 +1602,7 @@
   ///
   /// By default, performs semantic analysis to build the new OpenMP clause.
   /// Subclasses may override this routine to provide different behavior.
-  OMPClause *RebuildOMPDefaultClause(OpenMPDefaultClauseKind Kind,
-                                     SourceLocation KindKwLoc,
+  OMPClause *RebuildOMPDefaultClause(DefaultKind Kind, SourceLocation KindKwLoc,
                                      SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
                                      SourceLocation EndLoc) {
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -11887,8 +11887,7 @@
 }
 
 void OMPClauseReader::VisitOMPDefaultClause(OMPDefaultClause *C) {
-  C->setDefaultKind(
-       static_cast<OpenMPDefaultClauseKind>(Record.readInt()));
+  C->setDefaultKind(static_cast<llvm::omp::DefaultKind>(Record.readInt()));
   C->setLParenLoc(Record.readSourceLocation());
   C->setDefaultKindKwLoc(Record.readSourceLocation());
 }
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -6097,7 +6097,7 @@
 }
 
 void OMPClauseWriter::VisitOMPDefaultClause(OMPDefaultClause *C) {
-  Record.push_back(C->getDefaultKind());
+  Record.push_back(unsigned(C->getDefaultKind()));
   Record.AddSourceLocation(C->getLParenLoc());
   Record.AddSourceLocation(C->getDefaultKindKwLoc());
 }
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMPConstants.h b/llvm/include/llvm/Frontend/OpenMP/OMPConstants.h
--- a/llvm/include/llvm/Frontend/OpenMP/OMPConstants.h
+++ b/llvm/include/llvm/Frontend/OpenMP/OMPConstants.h
@@ -49,6 +49,16 @@
 #define OMP_RTL(Enum, ...) constexpr auto Enum = omp::RuntimeFunction::Enum;
 #include "llvm/Frontend/OpenMP/OMPKinds.def"
 
+/// IDs for the different default kinds.
+enum class DefaultKind {
+#define OMP_DEFAULT_KIND(Enum, Str, Value) Enum = Value,
+#include "llvm/Frontend/OpenMP/OMPKinds.def"
+};
+
+#define OMP_DEFAULT_KIND(Enum, ...)                                            \
+  constexpr auto Enum = omp::DefaultKind::Enum;
+#include "llvm/Frontend/OpenMP/OMPKinds.def"
+
 /// IDs for the different proc bind kinds.
 enum class ProcBindKind {
 #define OMP_PROC_BIND_KIND(Enum, Str, Value) Enum = Value,
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def b/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def
--- a/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def
+++ b/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def
@@ -342,6 +342,26 @@
 
 ///}
 
+/// Default kinds
+///
+///{
+
+#ifndef OMP_DEFAULT_KIND
+#define OMP_DEFAULT_KIND(Enum, Str, Value)
+#endif
+
+#define __OMP_DEFAULT_KIND(Name, Value)                                        \
+  OMP_DEFAULT_KIND(OMP_DEFAULT_##Name, #Name, Value)
+
+__OMP_DEFAULT_KIND(none, 2)
+__OMP_DEFAULT_KIND(shared, 3)
+__OMP_DEFAULT_KIND(unknown, 4)
+
+#undef __OMP_DEFAULT_KIND
+#undef OMP_DEFAULT_KIND
+
+///}
+
 /// Proc bind kinds
 ///
 ///{