diff --git a/clang/include/clang/AST/ASTNodeTraverser.h b/clang/include/clang/AST/ASTNodeTraverser.h
--- a/clang/include/clang/AST/ASTNodeTraverser.h
+++ b/clang/include/clang/AST/ASTNodeTraverser.h
@@ -214,6 +214,10 @@
   }
 
   void Visit(const OMPClause *C) {
+    if (OMPFailClause::classof(C)) {
+      Visit(static_cast<const OMPFailClause *>(C));
+      return;
+    }
     getNodeDelegate().AddChild([=] {
       getNodeDelegate().Visit(C);
       for (const auto *S : C->children())
@@ -221,6 +225,13 @@
     });
   }
 
+  void Visit(const OMPFailClause *C) {
+    getNodeDelegate().AddChild([=] {
+      getNodeDelegate().Visit(C);
+      const OMPClause *MOC = C->const_getMemoryOrderClause();
+      Visit(MOC);
+    });
+  }
   void Visit(const GenericSelectionExpr::ConstAssociation &A) {
     getNodeDelegate().AddChild([=] {
       getNodeDelegate().Visit(A);
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
@@ -2266,6 +2266,133 @@
   }
 };
 
+/// This represents 'fail' clause in the '#pragma omp atomic'
+/// directive.
+///
+/// \code
+/// #pragma omp atomic compare fail
+/// \endcode
+/// In this example directive '#pragma omp atomic compare' has 'fail' clause.
+class OMPFailClause final
+    : public OMPClause,
+      private llvm::TrailingObjects<OMPFailClause, SourceLocation,
+                                    OpenMPClauseKind> {
+  OMPClause *MemoryOrderClause;
+
+  friend class OMPClauseReader;
+  friend TrailingObjects;
+
+  /// Define the sizes of each trailing object array except the last one. This
+  /// is required for TrailingObjects to work properly.
+  size_t numTrailingObjects(OverloadToken<SourceLocation>) const {
+    // 2 locations: for '(' and argument location.
+    return 2;
+  }
+
+  /// Sets the location of '(' in fail clause.
+  void setLParenLoc(SourceLocation Loc) {
+    *getTrailingObjects<SourceLocation>() = Loc;
+  }
+
+  /// Sets the location of memoryOrder clause argument in fail clause.
+  void setArgumentLoc(SourceLocation Loc) {
+    *std::next(getTrailingObjects<SourceLocation>(), 1) = Loc;
+  }
+
+  /// Sets the mem_order clause for 'atomic compare fail' directive.
+  void setMemOrderClauseKind(OpenMPClauseKind MemOrder) {
+    OpenMPClauseKind *MOCK = getTrailingObjects<OpenMPClauseKind>();
+    *MOCK = MemOrder;
+  }
+
+  /// Sets the mem_order clause for 'atomic compare fail' directive.
+  void setMemOrderClause(OMPClause *MemoryOrderClauseParam) {
+    MemoryOrderClause = MemoryOrderClauseParam;
+  }
+public:
+  /// Build 'fail' clause.
+  ///
+  /// \param StartLoc Starting location of the clause.
+  /// \param EndLoc Ending location of the clause.
+  OMPFailClause(SourceLocation StartLoc, SourceLocation EndLoc)
+      : OMPClause(llvm::omp::OMPC_fail, StartLoc, EndLoc) {}
+
+  /// Build an empty clause.
+  OMPFailClause()
+      : OMPClause(llvm::omp::OMPC_fail, SourceLocation(), SourceLocation()) {}
+
+  static OMPFailClause *CreateEmpty(const ASTContext &C);
+  static OMPFailClause *Create(const ASTContext &C, SourceLocation StartLoc,
+                               SourceLocation EndLoc);
+
+  child_range children() {
+    return child_range(child_iterator(), child_iterator());
+  }
+
+
+  const_child_range children() const {
+    return const_child_range(const_child_iterator(), const_child_iterator());
+  }
+
+  child_range used_children() {
+    return child_range(child_iterator(), child_iterator());
+  }
+  const_child_range used_children() const {
+    return const_child_range(const_child_iterator(), const_child_iterator());
+  }
+
+  static bool classof(const OMPClause *T) {
+    return T->getClauseKind() == llvm::omp::OMPC_fail;
+  }
+
+  void initFailClause(SourceLocation LParenLoc, OMPClause *MemOClause,
+                      SourceLocation MemOrderLoc) {
+
+    setLParenLoc(LParenLoc);
+    MemoryOrderClause = MemOClause;
+    setArgumentLoc(MemOrderLoc);
+
+    OpenMPClauseKind ClauseKind = MemoryOrderClause->getClauseKind();
+    OpenMPClauseKind MemClauseKind = llvm::omp::OMPC_unknown;
+    switch(ClauseKind) {
+    case llvm::omp::OMPC_acq_rel:
+    case llvm::omp::OMPC_acquire:
+      MemClauseKind = llvm::omp::OMPC_acquire;
+      break;
+    case llvm::omp::OMPC_relaxed:
+    case llvm::omp::OMPC_release:
+      MemClauseKind = llvm::omp::OMPC_relaxed;
+      break;
+    case llvm::omp::OMPC_seq_cst:
+      MemClauseKind = llvm::omp::OMPC_seq_cst;
+      break;
+    default : break;
+    }
+    setMemOrderClauseKind(MemClauseKind);
+  }
+
+  /// Gets the location of '(' in fail clause.
+  SourceLocation getLParenLoc() const {
+    return *getTrailingObjects<SourceLocation>();
+  }
+
+  OMPClause *getMemoryOrderClause() { return MemoryOrderClause; }
+
+  const OMPClause *const_getMemoryOrderClause() const {
+    return static_cast<const OMPClause *>(MemoryOrderClause);
+  }
+
+  /// Gets the location of memoryOrder clause argument in fail clause.
+  SourceLocation getArgumentLoc() const {
+    return *std::next(getTrailingObjects<SourceLocation>(), 1);
+  }
+
+  /// Gets the dependence kind in clause for 'depobj' directive.
+  OpenMPClauseKind getMemOrderClauseKind() const {
+    return *getTrailingObjects<OpenMPClauseKind>();
+  }
+};
+
 /// This represents 'seq_cst' clause in the '#pragma omp atomic'
 /// directive.
 ///
diff --git a/clang/include/clang/AST/RecursiveASTVisitor.h b/clang/include/clang/AST/RecursiveASTVisitor.h
--- a/clang/include/clang/AST/RecursiveASTVisitor.h
+++ b/clang/include/clang/AST/RecursiveASTVisitor.h
@@ -3346,6 +3346,11 @@
   return true;
 }
 
+template <typename Derived>
+bool RecursiveASTVisitor<Derived>::VisitOMPFailClause(OMPFailClause *) {
+  return true;
+}
+
 template <typename Derived>
 bool RecursiveASTVisitor<Derived>::VisitOMPSeqCstClause(OMPSeqCstClause *) {
   return true;
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10633,6 +10633,10 @@
   "expect binary operator in conditional expression|expect '<', '>' or '==' as order operator|expect comparison in a form of 'x == e', 'e == x', 'x ordop expr', or 'expr ordop x'|"
   "expect lvalue for result value|expect scalar value|expect integer value|unexpected 'else' statement|expect '==' operator|expect an assignment statement 'v = x'|"
   "expect a 'if' statement|expect no more than two statements|expect a compound statement|expect 'else' statement|expect a form 'r = x == e; if (r) ...'}0">;
+def err_omp_atomic_fail_wrong_or_no_clauses : Error<"expected a memory order clause">;
+def err_omp_atomic_fail_extra_mem_order_clauses : Error<"directive '#pragma omp atomic compare fail' cannot contain more than one memory order clause">;
+def err_omp_atomic_fail_extra_clauses : Error<"directive '#pragma omp atomic compare' cannot contain more than one fail clause">;
+def err_omp_atomic_fail_no_compare : Error<"expected 'compare' clause with the 'fail' modifier">;
 def err_omp_atomic_several_clauses : Error<
   "directive '#pragma omp atomic' cannot contain more than one 'read', 'write', 'update', 'capture', or 'compare' clause">;
 def err_omp_several_mem_order_clauses : Error<
diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -433,6 +433,8 @@
   /// a statement expression and builds a suitable expression statement.
   StmtResult handleExprStmt(ExprResult E, ParsedStmtContext StmtCtx);
 
+  OMPClause *ParseOpenMPFailClause(OMPClause *Clause);
+
 public:
   Parser(Preprocessor &PP, Sema &Actions, bool SkipFunctionBodies);
   ~Parser() override;
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
@@ -11357,6 +11357,9 @@
   /// Called on well-formed 'compare' clause.
   OMPClause *ActOnOpenMPCompareClause(SourceLocation StartLoc,
                                       SourceLocation EndLoc);
+  /// Called on well-formed 'fail' clause.
+  OMPClause *ActOnOpenMPFailClause(SourceLocation StartLoc,
+                                   SourceLocation EndLoc);
   /// Called on well-formed 'seq_cst' clause.
   OMPClause *ActOnOpenMPSeqCstClause(SourceLocation StartLoc,
                                      SourceLocation EndLoc);
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
@@ -127,6 +127,7 @@
   case OMPC_update:
   case OMPC_capture:
   case OMPC_compare:
+  case OMPC_fail:
   case OMPC_seq_cst:
   case OMPC_acq_rel:
   case OMPC_acquire:
@@ -220,6 +221,7 @@
   case OMPC_update:
   case OMPC_capture:
   case OMPC_compare:
+  case OMPC_fail:
   case OMPC_seq_cst:
   case OMPC_acq_rel:
   case OMPC_acquire:
@@ -412,6 +414,25 @@
   return Clause;
 }
 
+OMPFailClause *OMPFailClause::Create(const ASTContext &C,
+                                     SourceLocation StartLoc,
+                                     SourceLocation EndLoc) {
+  void *Mem =
+      C.Allocate(totalSizeToAlloc<SourceLocation, OpenMPClauseKind>(2, 1),
+                 alignof(OMPFailClause));
+  auto *Clause =
+      new (Mem) OMPFailClause(StartLoc, EndLoc);
+  return Clause;
+}
+
+OMPFailClause *OMPFailClause::CreateEmpty(const ASTContext &C) {
+  void *Mem =
+      C.Allocate(totalSizeToAlloc<SourceLocation, OpenMPClauseKind>(2, 1),
+                 alignof(OMPFailClause));
+  auto *Clause = new (Mem) OMPFailClause();
+  return Clause;
+}
+
 void OMPPrivateClause::setPrivateCopies(ArrayRef<Expr *> VL) {
   assert(VL.size() == varlist_size() &&
          "Number of private copies is not the same as the preallocated buffer");
@@ -1847,6 +1868,16 @@
   OS << "compare";
 }
 
+void OMPClausePrinter::VisitOMPFailClause(OMPFailClause *Node) {
+  OS << "fail";
+  if(Node) {
+    OS << "(";
+    OS << getOpenMPSimpleClauseTypeName(Node->getClauseKind(),
+                       static_cast<int>(Node->getMemOrderClauseKind()));
+    OS << ")";
+  }
+}
+
 void OMPClausePrinter::VisitOMPSeqCstClause(OMPSeqCstClause *) {
   OS << "seq_cst";
 }
diff --git a/clang/lib/AST/StmtProfile.cpp b/clang/lib/AST/StmtProfile.cpp
--- a/clang/lib/AST/StmtProfile.cpp
+++ b/clang/lib/AST/StmtProfile.cpp
@@ -557,6 +557,8 @@
 
 void OMPClauseProfiler::VisitOMPCompareClause(const OMPCompareClause *) {}
 
+void OMPClauseProfiler::VisitOMPFailClause(const OMPFailClause *) {}
+
 void OMPClauseProfiler::VisitOMPSeqCstClause(const OMPSeqCstClause *) {}
 
 void OMPClauseProfiler::VisitOMPAcqRelClause(const OMPAcqRelClause *) {}
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
@@ -366,6 +366,20 @@
 #include "clang/Basic/OpenMPKinds.def"
     }
     llvm_unreachable("Invalid OpenMP 'depend' clause type");
+  case OMPC_fail: {
+    OpenMPClauseKind CK = static_cast<OpenMPClauseKind>(Type);
+    switch (CK) {
+    case OMPC_acquire:
+      return "acquire";
+    case OMPC_relaxed:
+      return "relaxed";
+    case OMPC_seq_cst:
+      return "seq_cst";
+    default:
+      return "unknown";
+    }
+    llvm_unreachable("Invalid OpenMP 'fail' clause modifier");
+  }
   case OMPC_device:
     switch (Type) {
     case OMPC_DEVICE_unknown:
diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -3234,6 +3234,7 @@
   case OMPC_write:
   case OMPC_capture:
   case OMPC_compare:
+  case OMPC_fail:
   case OMPC_seq_cst:
   case OMPC_acq_rel:
   case OMPC_acquire:
@@ -3620,6 +3621,45 @@
       Val.getValue().Loc, Val.getValue().RLoc);
 }
 
+OMPClause *Parser::ParseOpenMPFailClause(OMPClause *Clause) {
+
+  OMPFailClause *FailClause = static_cast<OMPFailClause *>(Clause);
+  SourceLocation LParenLoc;
+  if (Tok.is(tok::l_paren)) {
+    LParenLoc = Tok.getLocation();
+    ConsumeAnyToken();
+  } else {
+    Diag(diag::err_expected_lparen_after) << getOpenMPClauseName(OMPC_fail);
+    return Clause;
+  }
+
+
+  OpenMPClauseKind CKind = Tok.isAnnotation()
+				 ? OMPC_unknown
+				 : getOpenMPClauseKind(PP.getSpelling(Tok));
+  if (CKind == OMPC_unknown) {
+    Diag(diag::err_omp_expected_clause) << ("atomic compare fail");
+    return Clause;
+  }
+  OMPClause *MemoryOrderClause = ParseOpenMPClause(CKind, false);
+  SourceLocation MemOrderLoc;
+  // Store Memory Order SubClause for Sema.
+  if (MemoryOrderClause) {
+    MemOrderLoc = Tok.getLocation();
+  }
+
+  if (Tok.is(tok::r_paren)) {
+    FailClause->initFailClause(LParenLoc,MemoryOrderClause,MemOrderLoc);
+    ConsumeAnyToken();
+  } else {
+    const IdentifierInfo *Arg = Tok.getIdentifierInfo();
+    Diag(Tok, diag::err_expected_rparen_after)
+        << (Arg ? Arg->getName() : "atomic compare fail");
+  }
+
+  return Clause;
+}
+
 /// Parsing of OpenMP clauses like 'ordered'.
 ///
 ///    ordered-clause:
@@ -3652,7 +3692,11 @@
 
   if (ParseOnly)
     return nullptr;
-  return Actions.ActOnOpenMPClause(Kind, Loc, Tok.getLocation());
+  OMPClause *Clause = Actions.ActOnOpenMPClause(Kind, Loc, Tok.getLocation());
+  if (Kind == llvm::omp::Clause::OMPC_fail) {
+    Clause = ParseOpenMPFailClause(Clause);
+  }
+  return Clause;
 }
 
 /// Parsing of OpenMP clauses with single expressions and some additional
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
@@ -12026,6 +12026,68 @@
 
   return checkType(ErrorInfo);
 }
+
+class OpenMPAtomicFailChecker {
+
+protected:
+  Sema &SemaRef;
+  ASTContext &Context;
+
+public:
+  // Error descriptor type which will be returned to Sema
+  unsigned int ErrorNo;
+
+  OpenMPAtomicFailChecker(Sema &S) : SemaRef(S), Context(S.getASTContext()) {}
+
+  /// Check if all results conform with spec in terms of lvalue/rvalue
+  /// and scalar type.
+  bool checkSubClause(ArrayRef<OMPClause *> Clauses, SourceLocation *ErrorLoc);
+  /// Return the error descriptor that will guide the error message emission.
+  unsigned getErrorDesc() const { return ErrorNo; }
+};
+
+bool OpenMPAtomicFailChecker::checkSubClause(ArrayRef<OMPClause *> Clauses,
+                                             SourceLocation *ErrorLoc) {
+  int NoOfFails = 0;
+  ErrorNo = 0;
+  SourceLocation ClauseLoc;
+  for (const OMPClause *C : Clauses) {
+    if (C->getClauseKind() == OMPC_fail) {
+      NoOfFails++;
+      const OMPFailClause *FC = static_cast<const OMPFailClause *>(C);
+      const OMPClause *MemOrderC = FC->const_getMemoryOrderClause();
+      /* Clauses contains OMPC_fail and the subclause */
+      if (MemOrderC) {
+        OpenMPClauseKind ClauseKind = MemOrderC->getClauseKind();
+        if ((ClauseKind == OMPC_acq_rel) || (ClauseKind == OMPC_acquire) ||
+            (ClauseKind == OMPC_relaxed) || (ClauseKind == OMPC_release) ||
+            (ClauseKind == OMPC_seq_cst)) {
+          switch(ClauseKind) {
+          case OMPC_acq_rel :
+            ClauseKind = OMPC_acquire;
+            break;
+          case OMPC_release :
+            ClauseKind = OMPC_relaxed;
+            break;
+          default : break;
+          }
+          continue;
+        } else {
+          ErrorNo = diag::err_omp_atomic_fail_wrong_or_no_clauses;
+          *ErrorLoc = MemOrderC->getBeginLoc();
+          continue;
+        }
+      }
+    }
+  }
+  if (NoOfFails > 1) {
+    ErrorNo = diag::err_omp_atomic_fail_extra_clauses;
+    *ErrorLoc = ClauseLoc;
+  }
+
+  return !ErrorNo;
+}
+
 } // namespace
 
 StmtResult Sema::ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
@@ -12046,6 +12108,8 @@
   SourceLocation AtomicKindLoc;
   OpenMPClauseKind MemOrderKind = OMPC_unknown;
   SourceLocation MemOrderLoc;
+  llvm::omp::Clause SubClause = OMPC_unknown;
+  SourceLocation SubClauseLoc;
   bool MutexClauseEncountered = false;
   llvm::SmallSet<OpenMPClauseKind, 2> EncounteredAtomicKinds;
   for (const OMPClause *C : Clauses) {
@@ -12074,6 +12138,16 @@
       }
       break;
     }
+    case OMPC_fail: {
+      if (AtomicKind != OMPC_compare) {
+        Diag(C->getBeginLoc(), diag::err_omp_atomic_fail_no_compare)
+            << SourceRange(C->getBeginLoc(), C->getEndLoc());
+        return StmtError();
+      }
+      SubClause = OMPC_fail;
+      SubClauseLoc = C->getBeginLoc();
+      break;
+    }
     case OMPC_seq_cst:
     case OMPC_acq_rel:
     case OMPC_acquire:
@@ -12552,6 +12626,17 @@
       CE = Checker.getCond();
       // We reuse IsXLHSInRHSPart to tell if it is in the form 'x ordop expr'.
       IsXLHSInRHSPart = Checker.isXBinopExpr();
+      if (SubClause == OMPC_fail) {
+        OpenMPAtomicFailChecker Checker(*this);
+        SourceLocation ErrorLoc, NoteLoc;
+        NoteLoc = ErrorLoc = Body->getBeginLoc();
+        ErrorLoc = SubClauseLoc;
+        if (!Checker.checkSubClause(Clauses,&ErrorLoc)) {
+          unsigned ErrorNo = Checker.getErrorDesc();
+          Diag(ErrorLoc, ErrorNo);
+          return StmtError();
+        }
+      }
     }
   }
 
@@ -16491,6 +16576,9 @@
   case OMPC_compare:
     Res = ActOnOpenMPCompareClause(StartLoc, EndLoc);
     break;
+  case OMPC_fail:
+    Res = ActOnOpenMPFailClause(StartLoc, EndLoc);
+    break;
   case OMPC_seq_cst:
     Res = ActOnOpenMPSeqCstClause(StartLoc, EndLoc);
     break;
@@ -16644,6 +16732,11 @@
   return new (Context) OMPCompareClause(StartLoc, EndLoc);
 }
 
+OMPClause *Sema::ActOnOpenMPFailClause(SourceLocation StartLoc,
+                                       SourceLocation EndLoc) {
+  return OMPFailClause::Create(Context, StartLoc, EndLoc);
+}
+
 OMPClause *Sema::ActOnOpenMPSeqCstClause(SourceLocation StartLoc,
                                          SourceLocation EndLoc) {
   return new (Context) OMPSeqCstClause(StartLoc, 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
@@ -9559,6 +9559,13 @@
   return C;
 }
 
+template <typename Derived>
+OMPClause *
+TreeTransform<Derived>::TransformOMPFailClause(OMPFailClause *C) {
+  // No need to rebuild this clause, no template-dependent parameters.
+  return C;
+}
+
 template <typename Derived>
 OMPClause *
 TreeTransform<Derived>::TransformOMPSeqCstClause(OMPSeqCstClause *C) {
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
@@ -11744,6 +11744,9 @@
   case llvm::omp::OMPC_compare:
     C = new (Context) OMPCompareClause();
     break;
+  case llvm::omp::OMPC_fail:
+    C = OMPFailClause::CreateEmpty(Context);
+    break;
   case llvm::omp::OMPC_seq_cst:
     C = new (Context) OMPSeqCstClause();
     break;
@@ -12113,6 +12116,31 @@
 
 void OMPClauseReader::VisitOMPCompareClause(OMPCompareClause *) {}
 
+void OMPClauseReader::VisitOMPFailClause(OMPFailClause *C) {
+  C->setLParenLoc(Record.readSourceLocation());
+  SourceLocation SourceLoc = Record.readSourceLocation();
+  C->setArgumentLoc(SourceLoc);
+  OpenMPClauseKind CKind = Record.readEnum<OpenMPClauseKind>();
+  C->setMemOrderClauseKind(CKind);
+
+  SourceLocation EndLoc;
+  OMPClause *MemoryOrderClause = NULL;
+  switch(CKind) {
+  case llvm::omp::OMPC_acquire:
+    MemoryOrderClause = new (Context) OMPAcquireClause(SourceLoc, EndLoc);
+    break;
+  case llvm::omp::OMPC_relaxed:
+    MemoryOrderClause = new (Context) OMPRelaxedClause(SourceLoc, EndLoc);
+    break;
+  case llvm::omp::OMPC_seq_cst:
+    MemoryOrderClause = new (Context) OMPSeqCstClause(SourceLoc, EndLoc);
+    break;
+  default:
+    break;
+  }
+  C->setMemOrderClause(MemoryOrderClause);
+}
+
 void OMPClauseReader::VisitOMPSeqCstClause(OMPSeqCstClause *) {}
 
 void OMPClauseReader::VisitOMPAcqRelClause(OMPAcqRelClause *) {}
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
@@ -6327,6 +6327,14 @@
 
 void OMPClauseWriter::VisitOMPCompareClause(OMPCompareClause *) {}
 
+void OMPClauseWriter::VisitOMPFailClause(OMPFailClause *C) {
+  // Record.AddSourceLocation(C->getLParenLoc());
+  // Copied from VisitOMPUpdateClause
+  Record.AddSourceLocation(C->getLParenLoc());
+  Record.AddSourceLocation(C->getArgumentLoc());
+  Record.writeEnum(C->getMemOrderClauseKind());
+}
+
 void OMPClauseWriter::VisitOMPSeqCstClause(OMPSeqCstClause *) {}
 
 void OMPClauseWriter::VisitOMPAcqRelClause(OMPAcqRelClause *) {}
diff --git a/clang/test/OpenMP/atomic_ast_print.cpp b/clang/test/OpenMP/atomic_ast_print.cpp
--- a/clang/test/OpenMP/atomic_ast_print.cpp
+++ b/clang/test/OpenMP/atomic_ast_print.cpp
@@ -226,6 +226,16 @@
   { v = a; if (a < b) { a = b; } }
 #pragma omp atomic compare capture hint(6)
   { v = a == b; if (v) a = c; }
+#pragma omp atomic compare fail(acq_rel)
+  { if (a < c) { a = c; } }
+#pragma omp atomic compare fail(acquire)
+  { if (a < c) { a = c; } }
+#pragma omp atomic compare fail(release)
+  { if (a < c) { a = c; } }
+#pragma omp atomic compare fail(relaxed)
+  { if (a < c) { a = c; } }
+#pragma omp atomic compare fail(seq_cst)
+  { if (a < c) { a = c; } }
 #endif
   return T();
 }
@@ -1099,6 +1109,16 @@
   { v = a; if (a < b) { a = b; } }
 #pragma omp atomic compare capture hint(6)
   { v = a == b; if (v) a = c; }
+#pragma omp atomic compare fail(acq_rel)
+  if(a < b) { a = b; }
+#pragma omp atomic compare fail(acquire)
+  if(a < b) { a = b; }
+#pragma omp atomic compare fail(release)
+  if(a < b) { a = b; }
+#pragma omp atomic compare fail(relaxed)
+  if(a < b) { a = b; }
+#pragma omp atomic compare fail(seq_cst)
+  if(a < b) { a = b; }
 #endif
   // CHECK-NEXT: #pragma omp atomic
   // CHECK-NEXT: a++;
@@ -1429,6 +1449,26 @@
   // CHECK-51-NEXT: if (v)
   // CHECK-51-NEXT: a = c;
   // CHECK-51-NEXT: }
+  // CHECK-51-NEXT: #pragma omp atomic compare fail(acquire)
+  // CHECK-51-NEXT: if (a < b) {
+  // CHECK-51-NEXT: a = b;
+  // CHECK-51-NEXT: }
+  // CHECK-51-NEXT: #pragma omp atomic compare fail(acquire)
+  // CHECK-51-NEXT: if (a < b) {
+  // CHECK-51-NEXT: a = b;
+  // CHECK-51-NEXT: }
+  // CHECK-51-NEXT: #pragma omp atomic compare fail(relaxed)
+  // CHECK-51-NEXT: if (a < b) {
+  // CHECK-51-NEXT: a = b;
+  // CHECK-51-NEXT: }
+  // CHECK-51-NEXT: #pragma omp atomic compare fail(relaxed)
+  // CHECK-51-NEXT: if (a < b) {
+  // CHECK-51-NEXT: a = b;
+  // CHECK-51-NEXT: }
+  // CHECK-51-NEXT: #pragma omp atomic compare fail(seq_cst)
+  // CHECK-51-NEXT: if (a < b) {
+  // CHECK-51-NEXT: a = b;
+  // CHECK-51-NEXT: }
   // expect-note@+1 {{in instantiation of function template specialization 'foo<int>' requested here}}
   return foo(a);
 }
diff --git a/clang/test/OpenMP/atomic_messages.cpp b/clang/test/OpenMP/atomic_messages.cpp
--- a/clang/test/OpenMP/atomic_messages.cpp
+++ b/clang/test/OpenMP/atomic_messages.cpp
@@ -958,6 +958,24 @@
 // expected-error@+1 {{directive '#pragma omp atomic' cannot contain more than one 'capture' clause}}
 #pragma omp atomic compare compare capture capture
   { v = a; if (a > b) a = b; }
+// expected-error@+1 {{expected 'compare' clause with the 'fail' modifier}}
+#pragma omp atomic fail(seq_cst)
+  if(v == a) { v = a; }
+// expected-error@+1 {{expected '(' after 'fail'}}
+#pragma omp atomic compare fail
+  if(v < a) { v = a; }
+// expected-error@+1 {{expected a memory order clause}}
+#pragma omp atomic compare fail(capture)
+  if(v < a) { v = a; }
+ // expected-error@+2 {{expected ')' after 'atomic compare fail'}}
+ // expected-warning@+1 {{extra tokens at the end of '#pragma omp atomic' are ignored}}
+#pragma omp atomic compare fail(seq_cst | acquire)
+  if(v < a) { v = a; }
+// expected-error@+1 {{directive '#pragma omp atomic' cannot contain more than one 'fail' clause}}
+#pragma omp atomic compare fail(relaxed) fail(seq_cst)
+  if(v < a) { v = a; }
+
+
 #endif
   // expected-note@+1 {{in instantiation of function template specialization 'mixed<int>' requested here}}
   return mixed<int>();
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -2368,6 +2368,8 @@
 
 void OMPClauseEnqueue::VisitOMPCompareClause(const OMPCompareClause *) {}
 
+void OMPClauseEnqueue::VisitOMPFailClause(const OMPFailClause *) {}
+
 void OMPClauseEnqueue::VisitOMPSeqCstClause(const OMPSeqCstClause *) {}
 
 void OMPClauseEnqueue::VisitOMPAcqRelClause(const OMPAcqRelClause *) {}
diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -1807,6 +1807,7 @@
 CHECK_SIMPLE_CLAUSE(Align, OMPC_align)
 CHECK_SIMPLE_CLAUSE(Compare, OMPC_compare)
 CHECK_SIMPLE_CLAUSE(CancellationConstructType, OMPC_cancellation_construct_type)
+CHECK_SIMPLE_CLAUSE(Fail, OMPC_fail)
 
 CHECK_REQ_SCALAR_INT_CLAUSE(Grainsize, OMPC_grainsize)
 CHECK_REQ_SCALAR_INT_CLAUSE(NumTasks, OMPC_num_tasks)
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMP.td b/llvm/include/llvm/Frontend/OpenMP/OMP.td
--- a/llvm/include/llvm/Frontend/OpenMP/OMP.td
+++ b/llvm/include/llvm/Frontend/OpenMP/OMP.td
@@ -199,6 +199,7 @@
 def OMPC_Update : Clause<"update"> { let clangClass = "OMPUpdateClause"; }
 def OMPC_Capture : Clause<"capture"> { let clangClass = "OMPCaptureClause"; }
 def OMPC_Compare : Clause<"compare"> { let clangClass = "OMPCompareClause"; }
+def OMPC_Fail : Clause<"fail"> { let clangClass = "OMPFailClause"; }
 def OMPC_SeqCst : Clause<"seq_cst"> { let clangClass = "OMPSeqCstClause"; }
 def OMPC_AcqRel : Clause<"acq_rel"> { let clangClass = "OMPAcqRelClause"; }
 def OMPC_Acquire : Clause<"acquire"> { let clangClass = "OMPAcquireClause"; }
@@ -569,7 +570,8 @@
     VersionedClause<OMPC_Acquire, 50>,
     VersionedClause<OMPC_Release, 50>,
     VersionedClause<OMPC_Relaxed, 50>,
-    VersionedClause<OMPC_Hint, 50>
+    VersionedClause<OMPC_Hint, 50>,
+    VersionedClause<OMPC_Fail, 51>
   ];
 }
 def OMP_Target : Directive<"target"> {