[flang-commits] [flang] 085845a - [OMP5.2] Initial support for doacross clause.

Jennifer Yu via flang-commits flang-commits at lists.llvm.org
Thu Jun 29 12:07:38 PDT 2023


Author: Jennifer Yu
Date: 2023-06-29T11:58:17-07:00
New Revision: 085845a2acbefd26d5c229338225dfd76e2c2df3

URL: https://github.com/llvm/llvm-project/commit/085845a2acbefd26d5c229338225dfd76e2c2df3
DIFF: https://github.com/llvm/llvm-project/commit/085845a2acbefd26d5c229338225dfd76e2c2df3.diff

LOG: [OMP5.2] Initial support for doacross clause.

Added: 
    

Modified: 
    clang/include/clang/AST/OpenMPClause.h
    clang/include/clang/AST/RecursiveASTVisitor.h
    clang/include/clang/Basic/DiagnosticSemaKinds.td
    clang/include/clang/Basic/OpenMPKinds.def
    clang/include/clang/Basic/OpenMPKinds.h
    clang/include/clang/Sema/Sema.h
    clang/lib/AST/OpenMPClause.cpp
    clang/lib/AST/StmtProfile.cpp
    clang/lib/Basic/OpenMPKinds.cpp
    clang/lib/Parse/ParseOpenMP.cpp
    clang/lib/Sema/SemaOpenMP.cpp
    clang/lib/Sema/TreeTransform.h
    clang/lib/Serialization/ASTReader.cpp
    clang/lib/Serialization/ASTWriter.cpp
    clang/test/OpenMP/ordered_ast_print.cpp
    clang/test/OpenMP/ordered_messages.cpp
    clang/tools/libclang/CIndex.cpp
    flang/lib/Semantics/check-omp-structure.cpp
    llvm/include/llvm/Frontend/OpenMP/OMP.td

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/AST/OpenMPClause.h b/clang/include/clang/AST/OpenMPClause.h
index 627e9025c11289..0bea21270692cf 100644
--- a/clang/include/clang/AST/OpenMPClause.h
+++ b/clang/include/clang/AST/OpenMPClause.h
@@ -9046,6 +9046,132 @@ class OMPXDynCGroupMemClause
   Expr *getSize() const { return getStmtAs<Expr>(); }
 };
 
+/// This represents the 'doacross' clause for the '#pragma omp ordered'
+/// directive.
+///
+/// \code
+/// #pragma omp ordered doacross(sink: i-1, j-1)
+/// \endcode
+/// In this example directive '#pragma omp ordered' with clause 'doacross' with
+/// a dependence-type 'sink' and loop-iteration vector expressions i-1 and j-1.
+class OMPDoacrossClause final
+    : public OMPVarListClause<OMPDoacrossClause>,
+      private llvm::TrailingObjects<OMPDoacrossClause, Expr *> {
+  friend class OMPClauseReader;
+  friend OMPVarListClause;
+  friend TrailingObjects;
+
+  /// Dependence type (sink or source).
+  OpenMPDoacrossClauseModifier DepType = OMPC_DOACROSS_unknown;
+
+  /// Dependence type location.
+  SourceLocation DepLoc;
+
+  /// Colon location.
+  SourceLocation ColonLoc;
+
+  /// Number of loops, associated with the doacross clause.
+  unsigned NumLoops = 0;
+
+  /// Build clause with number of expressions \a N.
+  ///
+  /// \param StartLoc Starting location of the clause.
+  /// \param LParenLoc Location of '('.
+  /// \param EndLoc Ending location of the clause.
+  /// \param N Number of expressions in the clause.
+  /// \param NumLoops Number of loops associated with the clause.
+  OMPDoacrossClause(SourceLocation StartLoc, SourceLocation LParenLoc,
+                    SourceLocation EndLoc, unsigned N, unsigned NumLoops)
+      : OMPVarListClause<OMPDoacrossClause>(llvm::omp::OMPC_doacross, StartLoc,
+                                            LParenLoc, EndLoc, N),
+        NumLoops(NumLoops) {}
+
+  /// Build an empty clause.
+  ///
+  /// \param N Number of expressions in the clause.
+  /// \param NumLoops Number of loops associated with the clause.
+  explicit OMPDoacrossClause(unsigned N, unsigned NumLoops)
+      : OMPVarListClause<OMPDoacrossClause>(llvm::omp::OMPC_doacross,
+                                            SourceLocation(), SourceLocation(),
+                                            SourceLocation(), N),
+        NumLoops(NumLoops) {}
+
+  /// Set dependence type.
+  void setDependenceType(OpenMPDoacrossClauseModifier M) { DepType = M; }
+
+  /// Set dependence type location.
+  void setDependenceLoc(SourceLocation Loc) { DepLoc = Loc; }
+
+  /// Set colon location.
+  void setColonLoc(SourceLocation Loc) { ColonLoc = Loc; }
+
+public:
+  /// Creates clause with a list of expressions \a VL.
+  ///
+  /// \param C AST context.
+  /// \param StartLoc Starting location of the clause.
+  /// \param LParenLoc Location of '('.
+  /// \param EndLoc Ending location of the clause.
+  /// \param DepType The dependence type.
+  /// \param DepLoc Location of the dependence type.
+  /// \param ColonLoc Location of ':'.
+  /// \param VL List of references to the expressions.
+  /// \param NumLoops Number of loops that associated with the clause.
+  static OMPDoacrossClause *
+  Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc,
+         SourceLocation EndLoc, OpenMPDoacrossClauseModifier DepType,
+         SourceLocation DepLoc, SourceLocation ColonLoc, ArrayRef<Expr *> VL,
+         unsigned NumLoops);
+
+  /// Creates an empty clause with \a N expressions.
+  ///
+  /// \param C AST context.
+  /// \param N The number of expressions.
+  /// \param NumLoops Number of loops that is associated with this clause.
+  static OMPDoacrossClause *CreateEmpty(const ASTContext &C, unsigned N,
+                                        unsigned NumLoops);
+
+  /// Get dependence type.
+  OpenMPDoacrossClauseModifier getDependenceType() const { return DepType; }
+
+  /// Get dependence type location.
+  SourceLocation getDependenceLoc() const { return DepLoc; }
+
+  /// Get colon location.
+  SourceLocation getColonLoc() const { return ColonLoc; }
+
+  /// Get number of loops associated with the clause.
+  unsigned getNumLoops() const { return NumLoops; }
+
+  /// Set the loop data.
+  void setLoopData(unsigned NumLoop, Expr *Cnt);
+
+  /// Get the loop data.
+  Expr *getLoopData(unsigned NumLoop);
+  const Expr *getLoopData(unsigned NumLoop) const;
+
+  child_range children() {
+    return child_range(reinterpret_cast<Stmt **>(varlist_begin()),
+                       reinterpret_cast<Stmt **>(varlist_end()));
+  }
+
+  const_child_range children() const {
+    auto Children = const_cast<OMPDoacrossClause *>(this)->children();
+    return const_child_range(Children.begin(), Children.end());
+  }
+
+  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_doacross;
+  }
+};
+
 } // namespace clang
 
 #endif // LLVM_CLANG_AST_OPENMPCLAUSE_H

diff  --git a/clang/include/clang/AST/RecursiveASTVisitor.h b/clang/include/clang/AST/RecursiveASTVisitor.h
index 751249b57f9f1c..95b04fe3dd59b6 100644
--- a/clang/include/clang/AST/RecursiveASTVisitor.h
+++ b/clang/include/clang/AST/RecursiveASTVisitor.h
@@ -3864,6 +3864,13 @@ bool RecursiveASTVisitor<Derived>::VisitOMPXDynCGroupMemClause(
   return true;
 }
 
+template <typename Derived>
+bool RecursiveASTVisitor<Derived>::VisitOMPDoacrossClause(
+    OMPDoacrossClause *C) {
+  TRY_TO(VisitOMPClauseList(C));
+  return true;
+}
+
 // FIXME: look at the following tricky-seeming exprs to see if we
 // need to recurse on anything.  These are ones that have methods
 // returning decls or qualtypes or nestednamespecifier -- though I'm

diff  --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index c2b8bd4ce9cd96..edfa30abf594a2 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10868,7 +10868,7 @@ def note_omp_previous_named_if_clause : Note<
 def err_omp_ordered_directive_with_param : Error<
   "'ordered' directive %select{without any clauses|with 'threads' clause}0 cannot be closely nested inside ordered region with specified parameter">;
 def err_omp_ordered_directive_without_param : Error<
-  "'ordered' directive with 'depend' clause cannot be closely nested inside ordered region without specified parameter">;
+  "'ordered' directive with '%0' clause cannot be closely nested inside ordered region without specified parameter">;
 def note_omp_ordered_param : Note<
   "'ordered' clause%select{| with specified parameter}0">;
 def err_omp_expected_base_var_name : Error<
@@ -10900,7 +10900,7 @@ def note_omp_critical_hint_here : Note<
 def note_omp_critical_no_hint : Note<
   "%select{|previous }0directive with no 'hint' clause specified">;
 def err_omp_depend_clause_thread_simd : Error<
-  "'depend' clauses cannot be mixed with '%0' clause">;
+  "'%0' clauses cannot be mixed with '%1' clause">;
 def err_omp_depend_sink_expected_loop_iteration : Error<
   "expected%select{| %1}0 loop iteration variable">;
 def err_omp_depend_sink_unexpected_expr : Error<
@@ -10909,8 +10909,8 @@ def err_omp_depend_sink_expected_plus_minus : Error<
   "expected '+' or '-' operation">;
 def err_omp_taskwait_depend_mutexinoutset_not_allowed : Error<
   "'mutexinoutset' modifier not allowed in 'depend' clause on 'taskwait' directive">;
-def err_omp_depend_sink_source_not_allowed : Error<
-  "'depend(%select{source|sink:vec}0)' clause%select{|s}0 cannot be mixed with 'depend(%select{sink:vec|source}0)' clause%select{s|}0">;
+def err_omp_sink_and_source_not_allowed : Error<
+  "'%0(%select{source|sink:vec}1)' clause%select{|s}1 cannot be mixed with '%0(%select{sink:vec|source}1)' clause%select{s|}1">;
 def err_omp_depend_zero_length_array_section_not_allowed : Error<
   "zero-length array section is not allowed in 'depend' clause">;
 def err_omp_depend_sink_source_with_modifier : Error<

diff  --git a/clang/include/clang/Basic/OpenMPKinds.def b/clang/include/clang/Basic/OpenMPKinds.def
index 64c488caa6a9f4..eb5037c629dbf7 100644
--- a/clang/include/clang/Basic/OpenMPKinds.def
+++ b/clang/include/clang/Basic/OpenMPKinds.def
@@ -80,6 +80,9 @@
 #ifndef OPENMP_NUMTASKS_MODIFIER
 #define OPENMP_NUMTASKS_MODIFIER(Name)
 #endif
+#ifndef OPENMP_DOACROSS_MODIFIER
+#define OPENMP_DOACROSS_MODIFIER(Name)
+#endif
 
 // Static attributes for 'schedule' clause.
 OPENMP_SCHEDULE_KIND(static)
@@ -201,6 +204,10 @@ OPENMP_GRAINSIZE_MODIFIER(strict)
 // Modifiers for the 'num_tasks' clause.
 OPENMP_NUMTASKS_MODIFIER(strict)
 
+// Modifiers for the 'doacross' clause.
+OPENMP_DOACROSS_MODIFIER(source)
+OPENMP_DOACROSS_MODIFIER(sink)
+
 #undef OPENMP_NUMTASKS_MODIFIER
 #undef OPENMP_GRAINSIZE_MODIFIER
 #undef OPENMP_BIND_KIND
@@ -224,4 +231,5 @@ OPENMP_NUMTASKS_MODIFIER(strict)
 #undef OPENMP_DIST_SCHEDULE_KIND
 #undef OPENMP_DEFAULTMAP_KIND
 #undef OPENMP_DEFAULTMAP_MODIFIER
+#undef OPENMP_DOACROSS_MODIFIER
 

diff  --git a/clang/include/clang/Basic/OpenMPKinds.h b/clang/include/clang/Basic/OpenMPKinds.h
index 6491ee27782cbd..f5fc7a8ce5bb3c 100644
--- a/clang/include/clang/Basic/OpenMPKinds.h
+++ b/clang/include/clang/Basic/OpenMPKinds.h
@@ -215,6 +215,13 @@ enum OpenMPNumTasksClauseModifier {
   OMPC_NUMTASKS_unknown
 };
 
+/// OpenMP dependence types for 'doacross' clause.
+enum OpenMPDoacrossClauseModifier {
+#define OPENMP_DOACROSS_MODIFIER(Name) OMPC_DOACROSS_##Name,
+#include "clang/Basic/OpenMPKinds.def"
+  OMPC_DOACROSS_unknown
+};
+
 /// Contains 'interop' data for 'append_args' and 'init' clauses.
 class Expr;
 struct OMPInteropInfo final {

diff  --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 55d1dcf6ee0c26..4bf05b33bfb3ec 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -11032,10 +11032,7 @@ class Sema final {
   /// Initialization of data-sharing attributes stack.
   void InitDataSharingAttributesStack();
   void DestroyDataSharingAttributesStack();
-  ExprResult
-  VerifyPositiveIntegerConstantInClause(Expr *Op, OpenMPClauseKind CKind,
-                                        bool StrictlyPositive = true,
-                                        bool SuppressExprDiags = false);
+
   /// Returns OpenMP nesting level for current directive.
   unsigned getOpenMPNestingLevel() const;
 
@@ -11121,6 +11118,11 @@ class Sema final {
     return !OMPDeclareVariantScopes.empty();
   }
 
+  ExprResult
+  VerifyPositiveIntegerConstantInClause(Expr *Op, OpenMPClauseKind CKind,
+                                        bool StrictlyPositive = true,
+                                        bool SuppressExprDiags = false);
+
   /// Given the potential call expression \p Call, determine if there is a
   /// specialization via the OpenMP declare variant mechanism available. If
   /// there is, return the specialized call expression, otherwise return the
@@ -12281,6 +12283,13 @@ class Sema final {
                                             SourceLocation LParenLoc,
                                             SourceLocation EndLoc);
 
+  /// Called on well-formed 'doacross' clause.
+  OMPClause *
+  ActOnOpenMPDoacrossClause(OpenMPDoacrossClauseModifier DepType,
+                            SourceLocation DepLoc, SourceLocation ColonLoc,
+                            ArrayRef<Expr *> VarList, SourceLocation StartLoc,
+                            SourceLocation LParenLoc, SourceLocation EndLoc);
+
   /// The kind of conversion being performed.
   enum CheckedConversionKind {
     /// An implicit conversion.

diff  --git a/clang/lib/AST/OpenMPClause.cpp b/clang/lib/AST/OpenMPClause.cpp
index 2e88c08ae78986..4fc63093a87133 100644
--- a/clang/lib/AST/OpenMPClause.cpp
+++ b/clang/lib/AST/OpenMPClause.cpp
@@ -1669,6 +1669,52 @@ OMPBindClause::Create(const ASTContext &C, OpenMPBindClauseKind K,
 OMPBindClause *OMPBindClause::CreateEmpty(const ASTContext &C) {
   return new (C) OMPBindClause();
 }
+
+OMPDoacrossClause *
+OMPDoacrossClause::Create(const ASTContext &C, SourceLocation StartLoc,
+                          SourceLocation LParenLoc, SourceLocation EndLoc,
+                          OpenMPDoacrossClauseModifier DepType,
+                          SourceLocation DepLoc, SourceLocation ColonLoc,
+                          ArrayRef<Expr *> VL, unsigned NumLoops) {
+  void *Mem = C.Allocate(totalSizeToAlloc<Expr *>(VL.size() + NumLoops),
+                         alignof(OMPDoacrossClause));
+  OMPDoacrossClause *Clause = new (Mem)
+      OMPDoacrossClause(StartLoc, LParenLoc, EndLoc, VL.size(), NumLoops);
+  Clause->setDependenceType(DepType);
+  Clause->setDependenceLoc(DepLoc);
+  Clause->setColonLoc(ColonLoc);
+  Clause->setVarRefs(VL);
+  for (unsigned I = 0; I < NumLoops; ++I)
+    Clause->setLoopData(I, nullptr);
+  return Clause;
+}
+
+OMPDoacrossClause *OMPDoacrossClause::CreateEmpty(const ASTContext &C,
+                                                  unsigned N,
+                                                  unsigned NumLoops) {
+  void *Mem = C.Allocate(totalSizeToAlloc<Expr *>(N + NumLoops),
+                         alignof(OMPDoacrossClause));
+  return new (Mem) OMPDoacrossClause(N, NumLoops);
+}
+
+void OMPDoacrossClause::setLoopData(unsigned NumLoop, Expr *Cnt) {
+  assert(NumLoop < NumLoops && "Loop index must be less number of loops.");
+  auto *It = std::next(getVarRefs().end(), NumLoop);
+  *It = Cnt;
+}
+
+Expr *OMPDoacrossClause::getLoopData(unsigned NumLoop) {
+  assert(NumLoop < NumLoops && "Loop index must be less number of loops.");
+  auto *It = std::next(getVarRefs().end(), NumLoop);
+  return *It;
+}
+
+const Expr *OMPDoacrossClause::getLoopData(unsigned NumLoop) const {
+  assert(NumLoop < NumLoops && "Loop index must be less number of loops.");
+  const auto *It = std::next(getVarRefs().end(), NumLoop);
+  return *It;
+}
+
 //===----------------------------------------------------------------------===//
 //  OpenMP clauses printing methods
 //===----------------------------------------------------------------------===//
@@ -2464,6 +2510,14 @@ void OMPClausePrinter::VisitOMPXDynCGroupMemClause(
   OS << ")";
 }
 
+void OMPClausePrinter::VisitOMPDoacrossClause(OMPDoacrossClause *Node) {
+  OS << "doacross(";
+  OpenMPDoacrossClauseModifier DepType = Node->getDependenceType();
+  OS << (DepType == OMPC_DOACROSS_source ? "source:" : "sink:");
+  VisitOMPClauseList(Node, ' ');
+  OS << ")";
+}
+
 void OMPTraitInfo::getAsVariantMatchInfo(ASTContext &ASTCtx,
                                          VariantMatchInfo &VMI) const {
   for (const OMPTraitSet &Set : Sets) {

diff  --git a/clang/lib/AST/StmtProfile.cpp b/clang/lib/AST/StmtProfile.cpp
index 4d49f053e1f9ed..a9c4e14e87eff3 100644
--- a/clang/lib/AST/StmtProfile.cpp
+++ b/clang/lib/AST/StmtProfile.cpp
@@ -920,6 +920,9 @@ void OMPClauseProfiler::VisitOMPXDynCGroupMemClause(
   if (Expr *Size = C->getSize())
     Profiler->VisitStmt(Size);
 }
+void OMPClauseProfiler::VisitOMPDoacrossClause(const OMPDoacrossClause *C) {
+  VisitOMPClauseList(C);
+}
 } // namespace
 
 void

diff  --git a/clang/lib/Basic/OpenMPKinds.cpp b/clang/lib/Basic/OpenMPKinds.cpp
index 36bce7e44afbe5..48c9c2189a938a 100644
--- a/clang/lib/Basic/OpenMPKinds.cpp
+++ b/clang/lib/Basic/OpenMPKinds.cpp
@@ -50,6 +50,11 @@ unsigned clang::getOpenMPSimpleClauseType(OpenMPClauseKind Kind, StringRef Str,
       return OMPC_DEPEND_unknown;
     return Type;
   }
+  case OMPC_doacross:
+    return llvm::StringSwitch<OpenMPDoacrossClauseModifier>(Str)
+#define OPENMP_DOACROSS_MODIFIER(Name) .Case(#Name, OMPC_DOACROSS_##Name)
+#include "clang/Basic/OpenMPKinds.def"
+        .Default(OMPC_DOACROSS_unknown);
   case OMPC_linear:
     return llvm::StringSwitch<OpenMPLinearClauseKind>(Str)
 #define OPENMP_LINEAR_KIND(Name) .Case(#Name, OMPC_LINEAR_##Name)
@@ -282,6 +287,16 @@ const char *clang::getOpenMPSimpleClauseTypeName(OpenMPClauseKind Kind,
 #include "clang/Basic/OpenMPKinds.def"
     }
     llvm_unreachable("Invalid OpenMP 'depend' clause type");
+  case OMPC_doacross:
+    switch (Type) {
+    case OMPC_DOACROSS_unknown:
+      return "unknown";
+#define OPENMP_DOACROSS_MODIFIER(Name)                                         \
+  case OMPC_DOACROSS_##Name:                                                   \
+    return #Name;
+#include "clang/Basic/OpenMPKinds.def"
+    }
+    llvm_unreachable("Invalid OpenMP 'doacross' clause type");
   case OMPC_linear:
     switch (Type) {
     case OMPC_LINEAR_unknown:

diff  --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index 8c57dc9e071f95..8c4cf306bde2c4 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -2924,17 +2924,20 @@ StmtResult Parser::ParseOpenMPDeclarativeOrExecutableDirective(
     // Consume final annot_pragma_openmp_end.
     ConsumeAnnotationToken();
 
-    // OpenMP [2.13.8, ordered Construct, Syntax]
-    // If the depend clause is specified, the ordered construct is a stand-alone
-    // directive.
-    if (DKind == OMPD_ordered && FirstClauses[unsigned(OMPC_depend)].getInt()) {
-      if ((StmtCtx & ParsedStmtContext::AllowStandaloneOpenMPDirectives) ==
-          ParsedStmtContext()) {
-        Diag(Loc, diag::err_omp_immediate_directive)
-            << getOpenMPDirectiveName(DKind) << 1
-            << getOpenMPClauseName(OMPC_depend);
+    if (DKind == OMPD_ordered) {
+      // If the depend or doacross clause is specified, the ordered construct
+      // is a stand-alone directive.
+      for (auto CK : {OMPC_depend, OMPC_doacross}) {
+        if (FirstClauses[unsigned(CK)].getInt()) {
+          if ((StmtCtx & ParsedStmtContext::AllowStandaloneOpenMPDirectives) ==
+              ParsedStmtContext()) {
+            Diag(Loc, diag::err_omp_immediate_directive)
+                << getOpenMPDirectiveName(DKind) << 1
+                << getOpenMPClauseName(CK);
+          }
+          HasAssociatedStatement = false;
+        }
       }
-      HasAssociatedStatement = false;
     }
 
     if (DKind == OMPD_tile && !FirstClauses[unsigned(OMPC_sizes)].getInt()) {
@@ -3363,6 +3366,7 @@ OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
   case OMPC_inclusive:
   case OMPC_exclusive:
   case OMPC_affinity:
+  case OMPC_doacross:
     Clause = ParseOpenMPVarListClause(DKind, CKind, WrongDirective);
     break;
   case OMPC_sizes:
@@ -4366,7 +4370,7 @@ bool Parser::ParseOpenMPVarList(OpenMPDirectiveKind DKind,
     if (!InvalidReductionId)
       Data.ReductionOrMapperId =
           Actions.GetNameFromUnqualifiedId(UnqualifiedReductionId);
-  } else if (Kind == OMPC_depend) {
+  } else if (Kind == OMPC_depend || Kind == OMPC_doacross) {
     if (getLangOpts().OpenMP >= 50) {
       if (Tok.is(tok::identifier) && PP.getSpelling(Tok) == "iterator") {
         // Handle optional dependence modifier.
@@ -4389,13 +4393,16 @@ bool Parser::ParseOpenMPVarList(OpenMPDirectiveKind DKind,
         Kind, Tok.is(tok::identifier) ? PP.getSpelling(Tok) : "",
         getLangOpts());
     Data.ExtraModifierLoc = Tok.getLocation();
-    if (Data.ExtraModifier == OMPC_DEPEND_unknown) {
+    if ((Kind == OMPC_depend && Data.ExtraModifier == OMPC_DEPEND_unknown) ||
+        (Kind == OMPC_doacross &&
+         Data.ExtraModifier == OMPC_DOACROSS_unknown)) {
       SkipUntil(tok::colon, tok::r_paren, tok::annot_pragma_openmp_end,
                 StopBeforeMatch);
     } else {
       ConsumeToken();
       // Special processing for depend(source) clause.
-      if (DKind == OMPD_ordered && Data.ExtraModifier == OMPC_DEPEND_source) {
+      if (DKind == OMPD_ordered && Kind == OMPC_depend &&
+          Data.ExtraModifier == OMPC_DEPEND_source) {
         // Parse ')'.
         T.consumeClose();
         return false;
@@ -4406,7 +4413,13 @@ bool Parser::ParseOpenMPVarList(OpenMPDirectiveKind DKind,
     } else {
       Diag(Tok, DKind == OMPD_ordered ? diag::warn_pragma_expected_colon_r_paren
                                       : diag::warn_pragma_expected_colon)
-          << "dependency type";
+          << (Kind == OMPC_depend ? "dependency type" : "dependence-type");
+    }
+    // Special processing for doacross(source) clause.
+    if (Kind == OMPC_doacross && Data.ExtraModifier == OMPC_DOACROSS_source) {
+      // Parse ')'.
+      T.consumeClose();
+      return false;
     }
   } else if (Kind == OMPC_linear) {
     // Try to parse modifier if any.
@@ -4585,10 +4598,12 @@ bool Parser::ParseOpenMPVarList(OpenMPDirectiveKind DKind,
 
   bool IsComma =
       (Kind != OMPC_reduction && Kind != OMPC_task_reduction &&
-       Kind != OMPC_in_reduction && Kind != OMPC_depend && Kind != OMPC_map) ||
+       Kind != OMPC_in_reduction && Kind != OMPC_depend &&
+       Kind != OMPC_doacross && Kind != OMPC_map) ||
       (Kind == OMPC_reduction && !InvalidReductionId) ||
       (Kind == OMPC_map && Data.ExtraModifier != OMPC_MAP_unknown) ||
       (Kind == OMPC_depend && Data.ExtraModifier != OMPC_DEPEND_unknown) ||
+      (Kind == OMPC_doacross && Data.ExtraModifier != OMPC_DOACROSS_unknown) ||
       (Kind == OMPC_adjust_args &&
        Data.ExtraModifier != OMPC_ADJUST_ARGS_unknown);
   const bool MayHaveTail = (Kind == OMPC_linear || Kind == OMPC_aligned);
@@ -4646,7 +4661,8 @@ bool Parser::ParseOpenMPVarList(OpenMPDirectiveKind DKind,
   // Exit from scope when the iterator is used in depend clause.
   if (HasIterator)
     ExitScope();
-  return (Kind != OMPC_depend && Kind != OMPC_map && Vars.empty()) ||
+  return (Kind != OMPC_depend && Kind != OMPC_doacross && Kind != OMPC_map &&
+          Vars.empty()) ||
          (MustHaveTail && !Data.DepModOrTailExpr) || InvalidReductionId ||
          IsInvalidMapperModifier || InvalidIterator;
 }

diff  --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index e22425b208ccf6..2d7d6cf81732a9 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -88,8 +88,7 @@ class DSAStackTy {
   };
   using OperatorOffsetTy =
       llvm::SmallVector<std::pair<Expr *, OverloadedOperatorKind>, 4>;
-  using DoacrossDependMapTy =
-      llvm::DenseMap<OMPDependClause *, OperatorOffsetTy>;
+  using DoacrossClauseMapTy = llvm::DenseMap<OMPClause *, OperatorOffsetTy>;
   /// Kind of the declaration used in the uses_allocators clauses.
   enum class UsesAllocatorsDeclKind {
     /// Predefined allocator
@@ -170,7 +169,7 @@ class DSAStackTy {
     /// Set of 'depend' clauses with 'sink|source' dependence kind. Required to
     /// get the data (loop counters etc.) about enclosing loop-based construct.
     /// This data is required during codegen.
-    DoacrossDependMapTy DoacrossDepends;
+    DoacrossClauseMapTy DoacrossDepends;
     /// First argument (Expr *) contains optional argument of the
     /// 'ordered' clause, the second one is true if the regions has 'ordered'
     /// clause, false otherwise.
@@ -1055,17 +1054,16 @@ class DSAStackTy {
     assert(!isStackEmpty());
     return getStackSize() - 1;
   }
-  void addDoacrossDependClause(OMPDependClause *C,
-                               const OperatorOffsetTy &OpsOffs) {
+  void addDoacrossDependClause(OMPClause *C, const OperatorOffsetTy &OpsOffs) {
     SharingMapTy *Parent = getSecondOnStackOrNull();
     assert(Parent && isOpenMPWorksharingDirective(Parent->Directive));
     Parent->DoacrossDepends.try_emplace(C, OpsOffs);
   }
-  llvm::iterator_range<DoacrossDependMapTy::const_iterator>
+  llvm::iterator_range<DoacrossClauseMapTy::const_iterator>
   getDoacrossDependClauses() const {
     const SharingMapTy &StackElem = getTopOfStack();
     if (isOpenMPWorksharingDirective(StackElem.Directive)) {
-      const DoacrossDependMapTy &Ref = StackElem.DoacrossDepends;
+      const DoacrossClauseMapTy &Ref = StackElem.DoacrossDepends;
       return llvm::make_range(Ref.begin(), Ref.end());
     }
     return llvm::make_range(StackElem.DoacrossDepends.end(),
@@ -9335,30 +9333,45 @@ static bool checkOpenMPIterationSpace(
       }
     }
     for (auto &Pair : DSA.getDoacrossDependClauses()) {
-      if (CurrentNestedLoopCount >= Pair.first->getNumLoops()) {
+      auto *DependC = dyn_cast<OMPDependClause>(Pair.first);
+      auto *DoacrossC = dyn_cast<OMPDoacrossClause>(Pair.first);
+      unsigned NumLoops =
+          DependC ? DependC->getNumLoops() : DoacrossC->getNumLoops();
+      if (CurrentNestedLoopCount >= NumLoops) {
         // Erroneous case - clause has some problems.
         continue;
       }
-      if (Pair.first->getDependencyKind() == OMPC_DEPEND_sink &&
+      if (DependC && DependC->getDependencyKind() == OMPC_DEPEND_sink &&
           Pair.second.size() <= CurrentNestedLoopCount) {
         // Erroneous case - clause has some problems.
-        Pair.first->setLoopData(CurrentNestedLoopCount, nullptr);
+        DependC->setLoopData(CurrentNestedLoopCount, nullptr);
+        continue;
+      }
+      if (DoacrossC && DoacrossC->getDependenceType() == OMPC_DOACROSS_sink &&
+          Pair.second.size() <= CurrentNestedLoopCount) {
+        // Erroneous case - clause has some problems.
+        DoacrossC->setLoopData(CurrentNestedLoopCount, nullptr);
         continue;
       }
       Expr *CntValue;
-      if (Pair.first->getDependencyKind() == OMPC_DEPEND_source)
+      SourceLocation DepLoc =
+          DependC ? DependC->getDependencyLoc() : DoacrossC->getDependenceLoc();
+      if ((DependC && DependC->getDependencyKind() == OMPC_DEPEND_source) ||
+          (DoacrossC && DoacrossC->getDependenceType() == OMPC_DOACROSS_source))
         CntValue = ISC.buildOrderedLoopData(
             DSA.getCurScope(),
             ResultIterSpaces[CurrentNestedLoopCount].CounterVar, Captures,
-            Pair.first->getDependencyLoc());
+            DepLoc);
       else
         CntValue = ISC.buildOrderedLoopData(
             DSA.getCurScope(),
             ResultIterSpaces[CurrentNestedLoopCount].CounterVar, Captures,
-            Pair.first->getDependencyLoc(),
-            Pair.second[CurrentNestedLoopCount].first,
+            DepLoc, Pair.second[CurrentNestedLoopCount].first,
             Pair.second[CurrentNestedLoopCount].second);
-      Pair.first->setLoopData(CurrentNestedLoopCount, CntValue);
+      if (DependC)
+        DependC->setLoopData(CurrentNestedLoopCount, CntValue);
+      else
+        DoacrossC->setLoopData(CurrentNestedLoopCount, CntValue);
     }
   }
 
@@ -11274,33 +11287,47 @@ StmtResult Sema::ActOnOpenMPOrderedDirective(ArrayRef<OMPClause *> Clauses,
   const OMPClause *DependFound = nullptr;
   const OMPClause *DependSourceClause = nullptr;
   const OMPClause *DependSinkClause = nullptr;
+  const OMPClause *DoacrossFound = nullptr;
+  const OMPClause *DoacrossSourceClause = nullptr;
+  const OMPClause *DoacrossSinkClause = nullptr;
   bool ErrorFound = false;
   const OMPThreadsClause *TC = nullptr;
   const OMPSIMDClause *SC = nullptr;
   for (const OMPClause *C : Clauses) {
-    if (auto *DC = dyn_cast<OMPDependClause>(C)) {
-      DependFound = C;
-      if (DC->getDependencyKind() == OMPC_DEPEND_source) {
-        if (DependSourceClause) {
+    auto DOC = dyn_cast<OMPDoacrossClause>(C);
+    auto DC = dyn_cast<OMPDependClause>(C);
+    if (DC || DOC) {
+      DependFound = DC ? C : nullptr;
+      DoacrossFound = DOC ? C : nullptr;
+      if ((DC && DC->getDependencyKind() == OMPC_DEPEND_source) ||
+          (DOC && DOC->getDependenceType() == OMPC_DOACROSS_source)) {
+        if ((DC && DependSourceClause) || (DOC && DoacrossSourceClause)) {
           Diag(C->getBeginLoc(), diag::err_omp_more_one_clause)
               << getOpenMPDirectiveName(OMPD_ordered)
-              << getOpenMPClauseName(OMPC_depend) << 2;
+              << getOpenMPClauseName(DC ? OMPC_depend : OMPC_doacross) << 2;
           ErrorFound = true;
         } else {
-          DependSourceClause = C;
+          if (DC)
+            DependSourceClause = C;
+          else
+            DoacrossSourceClause = C;
         }
-        if (DependSinkClause) {
-          Diag(C->getBeginLoc(), diag::err_omp_depend_sink_source_not_allowed)
-              << 0;
+        if ((DC && DependSinkClause) || (DOC && DoacrossSinkClause)) {
+          Diag(C->getBeginLoc(), diag::err_omp_sink_and_source_not_allowed)
+              << (DC ? "depend" : "doacross") << 0;
           ErrorFound = true;
         }
-      } else if (DC->getDependencyKind() == OMPC_DEPEND_sink) {
-        if (DependSourceClause) {
-          Diag(C->getBeginLoc(), diag::err_omp_depend_sink_source_not_allowed)
-              << 1;
+      } else if ((DC && DC->getDependencyKind() == OMPC_DEPEND_sink) ||
+                 (DOC && DOC->getDependenceType() == OMPC_DOACROSS_sink)) {
+        if (DependSourceClause || DoacrossSourceClause) {
+          Diag(C->getBeginLoc(), diag::err_omp_sink_and_source_not_allowed)
+              << (DC ? "depend" : "doacross") << 1;
           ErrorFound = true;
         }
-        DependSinkClause = C;
+        if (DC)
+          DependSinkClause = C;
+        else
+          DoacrossSinkClause = C;
       }
     } else if (C->getClauseKind() == OMPC_threads) {
       TC = cast<OMPThreadsClause>(C);
@@ -11316,13 +11343,19 @@ StmtResult Sema::ActOnOpenMPOrderedDirective(ArrayRef<OMPClause *> Clauses,
     Diag(StartLoc, diag::err_omp_prohibited_region_simd)
         << (LangOpts.OpenMP >= 50 ? 1 : 0);
     ErrorFound = true;
-  } else if (DependFound && (TC || SC)) {
-    Diag(DependFound->getBeginLoc(), diag::err_omp_depend_clause_thread_simd)
+  } else if ((DependFound || DoacrossFound) && (TC || SC)) {
+    SourceLocation Loc =
+        DependFound ? DependFound->getBeginLoc() : DoacrossFound->getBeginLoc();
+    Diag(Loc, diag::err_omp_depend_clause_thread_simd)
+        << getOpenMPClauseName(DependFound ? OMPC_depend : OMPC_doacross)
         << getOpenMPClauseName(TC ? TC->getClauseKind() : SC->getClauseKind());
     ErrorFound = true;
-  } else if (DependFound && !DSAStack->getParentOrderedRegionParam().first) {
-    Diag(DependFound->getBeginLoc(),
-         diag::err_omp_ordered_directive_without_param);
+  } else if ((DependFound || DoacrossFound) &&
+             !DSAStack->getParentOrderedRegionParam().first) {
+    SourceLocation Loc =
+        DependFound ? DependFound->getBeginLoc() : DoacrossFound->getBeginLoc();
+    Diag(Loc, diag::err_omp_ordered_directive_without_param)
+        << getOpenMPClauseName(DependFound ? OMPC_depend : OMPC_doacross);
     ErrorFound = true;
   } else if (TC || Clauses.empty()) {
     if (const Expr *Param = DSAStack->getParentOrderedRegionParam().first) {
@@ -11333,7 +11366,7 @@ StmtResult Sema::ActOnOpenMPOrderedDirective(ArrayRef<OMPClause *> Clauses,
       ErrorFound = true;
     }
   }
-  if ((!AStmt && !DependFound) || ErrorFound)
+  if ((!AStmt && !DependFound && !DoacrossFound) || ErrorFound)
     return StmtError();
 
   // OpenMP 5.0, 2.17.9, ordered Construct, Restrictions.
@@ -11341,7 +11374,7 @@ StmtResult Sema::ActOnOpenMPOrderedDirective(ArrayRef<OMPClause *> Clauses,
   // within a worksharing-loop, simd, or worksharing-loop SIMD region, a thread
   // must not execute more than one ordered region corresponding to an ordered
   // construct without a depend clause.
-  if (!DependFound) {
+  if (!DependFound && !DoacrossFound) {
     if (DSAStack->doesParentHasOrderedDirective()) {
       Diag(StartLoc, diag::err_omp_several_directives_in_region) << "ordered";
       Diag(DSAStack->getParentOrderedDirectiveLoc(),
@@ -17904,6 +17937,11 @@ OMPClause *Sema::ActOnOpenMPVarListClause(OpenMPClauseKind Kind,
     Res = ActOnOpenMPAffinityClause(StartLoc, LParenLoc, ColonLoc, EndLoc,
                                     Data.DepModOrTailExpr, VarList);
     break;
+  case OMPC_doacross:
+    Res = ActOnOpenMPDoacrossClause(
+        static_cast<OpenMPDoacrossClauseModifier>(ExtraModifier),
+        ExtraModifierLoc, ColonLoc, VarList, StartLoc, LParenLoc, EndLoc);
+    break;
   case OMPC_if:
   case OMPC_depobj:
   case OMPC_final:
@@ -20525,71 +20563,35 @@ OMPClause *Sema::ActOnOpenMPDepobjClause(Expr *Depobj, SourceLocation StartLoc,
   return OMPDepobjClause::Create(Context, StartLoc, LParenLoc, EndLoc, Depobj);
 }
 
-OMPClause *
-Sema::ActOnOpenMPDependClause(const OMPDependClause::DependDataTy &Data,
-                              Expr *DepModifier, ArrayRef<Expr *> VarList,
-                              SourceLocation StartLoc, SourceLocation LParenLoc,
-                              SourceLocation EndLoc) {
-  OpenMPDependClauseKind DepKind = Data.DepKind;
-  SourceLocation DepLoc = Data.DepLoc;
-  if (DSAStack->getCurrentDirective() == OMPD_ordered &&
-      DepKind != OMPC_DEPEND_source && DepKind != OMPC_DEPEND_sink) {
-    Diag(DepLoc, diag::err_omp_unexpected_clause_value)
-        << "'source' or 'sink'" << getOpenMPClauseName(OMPC_depend);
-    return nullptr;
-  }
-  if (DSAStack->getCurrentDirective() == OMPD_taskwait &&
-      DepKind == OMPC_DEPEND_mutexinoutset) {
-    Diag(DepLoc, diag::err_omp_taskwait_depend_mutexinoutset_not_allowed);
-    return nullptr;
-  }
-  if ((DSAStack->getCurrentDirective() != OMPD_ordered ||
-       DSAStack->getCurrentDirective() == OMPD_depobj) &&
-      (DepKind == OMPC_DEPEND_unknown || DepKind == OMPC_DEPEND_source ||
-       DepKind == OMPC_DEPEND_sink ||
-       ((LangOpts.OpenMP < 50 ||
-         DSAStack->getCurrentDirective() == OMPD_depobj) &&
-        DepKind == OMPC_DEPEND_depobj))) {
-    SmallVector<unsigned, 6> Except = {OMPC_DEPEND_source, OMPC_DEPEND_sink,
-                                       OMPC_DEPEND_outallmemory,
-                                       OMPC_DEPEND_inoutallmemory};
-    if (LangOpts.OpenMP < 50 || DSAStack->getCurrentDirective() == OMPD_depobj)
-      Except.push_back(OMPC_DEPEND_depobj);
-    if (LangOpts.OpenMP < 51)
-      Except.push_back(OMPC_DEPEND_inoutset);
-    std::string Expected = (LangOpts.OpenMP >= 50 && !DepModifier)
-                               ? "depend modifier(iterator) or "
-                               : "";
-    Diag(DepLoc, diag::err_omp_unexpected_clause_value)
-        << Expected + getListOfPossibleValues(OMPC_depend, /*First=*/0,
-                                              /*Last=*/OMPC_DEPEND_unknown,
-                                              Except)
-        << getOpenMPClauseName(OMPC_depend);
-    return nullptr;
-  }
-  if (DepModifier &&
-      (DepKind == OMPC_DEPEND_source || DepKind == OMPC_DEPEND_sink)) {
-    Diag(DepModifier->getExprLoc(),
-         diag::err_omp_depend_sink_source_with_modifier);
-    return nullptr;
-  }
-  if (DepModifier &&
-      !DepModifier->getType()->isSpecificBuiltinType(BuiltinType::OMPIterator))
-    Diag(DepModifier->getExprLoc(), diag::err_omp_depend_modifier_not_iterator);
+namespace {
+// Utility struct that gathers the related info for doacross clause.
+struct DoacrossDataInfoTy {
+  // The list of expressions.
+  SmallVector<Expr *, 8> Vars;
+  // The OperatorOffset for doacross loop.
+  DSAStackTy::OperatorOffsetTy OpsOffs;
+  // The depended loop count.
+  llvm::APSInt TotalDepCount;
+};
+} // namespace
+static DoacrossDataInfoTy
+ProcessOpenMPDoacrossClauseCommon(Sema &SemaRef, bool IsSource,
+                                  ArrayRef<Expr *> VarList, DSAStackTy *Stack,
+                                  SourceLocation EndLoc) {
 
   SmallVector<Expr *, 8> Vars;
   DSAStackTy::OperatorOffsetTy OpsOffs;
   llvm::APSInt DepCounter(/*BitWidth=*/32);
   llvm::APSInt TotalDepCount(/*BitWidth=*/32);
-  if (DepKind == OMPC_DEPEND_sink || DepKind == OMPC_DEPEND_source) {
-    if (const Expr *OrderedCountExpr =
-            DSAStack->getParentOrderedRegionParam().first) {
-      TotalDepCount = OrderedCountExpr->EvaluateKnownConstInt(Context);
-      TotalDepCount.setIsUnsigned(/*Val=*/true);
-    }
+
+  if (const Expr *OrderedCountExpr =
+          Stack->getParentOrderedRegionParam().first) {
+    TotalDepCount = OrderedCountExpr->EvaluateKnownConstInt(SemaRef.Context);
+    TotalDepCount.setIsUnsigned(/*Val=*/true);
   }
+
   for (Expr *RefExpr : VarList) {
-    assert(RefExpr && "NULL expr in OpenMP shared clause.");
+    assert(RefExpr && "NULL expr in OpenMP doacross clause.");
     if (isa<DependentScopeDeclRefExpr>(RefExpr)) {
       // It will be analyzed later.
       Vars.push_back(RefExpr);
@@ -20598,10 +20600,10 @@ Sema::ActOnOpenMPDependClause(const OMPDependClause::DependDataTy &Data,
 
     SourceLocation ELoc = RefExpr->getExprLoc();
     Expr *SimpleExpr = RefExpr->IgnoreParenCasts();
-    if (DepKind == OMPC_DEPEND_sink) {
-      if (DSAStack->getParentOrderedRegionParam().first &&
+    if (!IsSource) {
+      if (Stack->getParentOrderedRegionParam().first &&
           DepCounter >= TotalDepCount) {
-        Diag(ELoc, diag::err_omp_depend_sink_unexpected_expr);
+        SemaRef.Diag(ELoc, diag::err_omp_depend_sink_unexpected_expr);
         continue;
       }
       ++DepCounter;
@@ -20613,7 +20615,7 @@ Sema::ActOnOpenMPDependClause(const OMPDependClause::DependDataTy &Data,
       // directive, xi denotes the loop iteration variable of the i-th nested
       // loop associated with the loop directive, and di is a constant
       // non-negative integer.
-      if (CurContext->isDependentContext()) {
+      if (SemaRef.CurContext->isDependentContext()) {
         // It will be analyzed later.
         Vars.push_back(RefExpr);
         continue;
@@ -20644,7 +20646,7 @@ Sema::ActOnOpenMPDependClause(const OMPDependClause::DependDataTy &Data,
       }
       SourceLocation ELoc;
       SourceRange ERange;
-      auto Res = getPrivateItem(*this, LHS, ELoc, ERange);
+      auto Res = getPrivateItem(SemaRef, LHS, ELoc, ERange);
       if (Res.second) {
         // It will be analyzed later.
         Vars.push_back(RefExpr);
@@ -20654,129 +20656,213 @@ Sema::ActOnOpenMPDependClause(const OMPDependClause::DependDataTy &Data,
         continue;
 
       if (OOK != OO_Plus && OOK != OO_Minus && (RHS || OOK != OO_None)) {
-        Diag(OOLoc, diag::err_omp_depend_sink_expected_plus_minus);
+        SemaRef.Diag(OOLoc, diag::err_omp_depend_sink_expected_plus_minus);
         continue;
       }
       if (RHS) {
-        ExprResult RHSRes = VerifyPositiveIntegerConstantInClause(
+        ExprResult RHSRes = SemaRef.VerifyPositiveIntegerConstantInClause(
             RHS, OMPC_depend, /*StrictlyPositive=*/false);
         if (RHSRes.isInvalid())
           continue;
       }
-      if (!CurContext->isDependentContext() &&
-          DSAStack->getParentOrderedRegionParam().first &&
-          DepCounter != DSAStack->isParentLoopControlVariable(D).first) {
+      if (!SemaRef.CurContext->isDependentContext() &&
+          Stack->getParentOrderedRegionParam().first &&
+          DepCounter != Stack->isParentLoopControlVariable(D).first) {
         const ValueDecl *VD =
-            DSAStack->getParentLoopControlVariable(DepCounter.getZExtValue());
+            Stack->getParentLoopControlVariable(DepCounter.getZExtValue());
         if (VD)
-          Diag(ELoc, diag::err_omp_depend_sink_expected_loop_iteration)
+          SemaRef.Diag(ELoc, diag::err_omp_depend_sink_expected_loop_iteration)
               << 1 << VD;
         else
-          Diag(ELoc, diag::err_omp_depend_sink_expected_loop_iteration) << 0;
+          SemaRef.Diag(ELoc, diag::err_omp_depend_sink_expected_loop_iteration)
+              << 0;
         continue;
       }
       OpsOffs.emplace_back(RHS, OOK);
-    } else {
-      bool OMPDependTFound = LangOpts.OpenMP >= 50;
-      if (OMPDependTFound)
-        OMPDependTFound = findOMPDependT(*this, StartLoc, DSAStack,
-                                         DepKind == OMPC_DEPEND_depobj);
-      if (DepKind == OMPC_DEPEND_depobj) {
-        // OpenMP 5.0, 2.17.11 depend Clause, Restrictions, C/C++
-        // List items used in depend clauses with the depobj dependence type
-        // must be expressions of the omp_depend_t type.
-        if (!RefExpr->isValueDependent() && !RefExpr->isTypeDependent() &&
-            !RefExpr->isInstantiationDependent() &&
-            !RefExpr->containsUnexpandedParameterPack() &&
-            (OMPDependTFound &&
-             !Context.hasSameUnqualifiedType(DSAStack->getOMPDependT(),
-                                             RefExpr->getType()))) {
-          Diag(ELoc, diag::err_omp_expected_omp_depend_t_lvalue)
-              << 0 << RefExpr->getType() << RefExpr->getSourceRange();
-          continue;
-        }
-        if (!RefExpr->isLValue()) {
-          Diag(ELoc, diag::err_omp_expected_omp_depend_t_lvalue)
-              << 1 << RefExpr->getType() << RefExpr->getSourceRange();
-          continue;
-        }
-      } else {
-        // OpenMP 5.0 [2.17.11, Restrictions]
-        // List items used in depend clauses cannot be zero-length array
-        // sections.
-        QualType ExprTy = RefExpr->getType().getNonReferenceType();
-        const auto *OASE = dyn_cast<OMPArraySectionExpr>(SimpleExpr);
-        if (OASE) {
-          QualType BaseType =
-              OMPArraySectionExpr::getBaseOriginalType(OASE->getBase());
-          if (const auto *ATy = BaseType->getAsArrayTypeUnsafe())
-            ExprTy = ATy->getElementType();
-          else
-            ExprTy = BaseType->getPointeeType();
-          ExprTy = ExprTy.getNonReferenceType();
-          const Expr *Length = OASE->getLength();
-          Expr::EvalResult Result;
-          if (Length && !Length->isValueDependent() &&
-              Length->EvaluateAsInt(Result, Context) &&
-              Result.Val.getInt().isZero()) {
-            Diag(ELoc,
-                 diag::err_omp_depend_zero_length_array_section_not_allowed)
-                << SimpleExpr->getSourceRange();
+    }
+    Vars.push_back(RefExpr->IgnoreParenImpCasts());
+  }
+  if (!SemaRef.CurContext->isDependentContext() && !IsSource &&
+      TotalDepCount > VarList.size() &&
+      Stack->getParentOrderedRegionParam().first &&
+      Stack->getParentLoopControlVariable(VarList.size() + 1)) {
+    SemaRef.Diag(EndLoc, diag::err_omp_depend_sink_expected_loop_iteration)
+        << 1 << Stack->getParentLoopControlVariable(VarList.size() + 1);
+  }
+  return {Vars, OpsOffs, TotalDepCount};
+}
+
+OMPClause *
+Sema::ActOnOpenMPDependClause(const OMPDependClause::DependDataTy &Data,
+                              Expr *DepModifier, ArrayRef<Expr *> VarList,
+                              SourceLocation StartLoc, SourceLocation LParenLoc,
+                              SourceLocation EndLoc) {
+  OpenMPDependClauseKind DepKind = Data.DepKind;
+  SourceLocation DepLoc = Data.DepLoc;
+  if (DSAStack->getCurrentDirective() == OMPD_ordered &&
+      DepKind != OMPC_DEPEND_source && DepKind != OMPC_DEPEND_sink) {
+    Diag(DepLoc, diag::err_omp_unexpected_clause_value)
+        << "'source' or 'sink'" << getOpenMPClauseName(OMPC_depend);
+    return nullptr;
+  }
+  if (DSAStack->getCurrentDirective() == OMPD_taskwait &&
+      DepKind == OMPC_DEPEND_mutexinoutset) {
+    Diag(DepLoc, diag::err_omp_taskwait_depend_mutexinoutset_not_allowed);
+    return nullptr;
+  }
+  if ((DSAStack->getCurrentDirective() != OMPD_ordered ||
+       DSAStack->getCurrentDirective() == OMPD_depobj) &&
+      (DepKind == OMPC_DEPEND_unknown || DepKind == OMPC_DEPEND_source ||
+       DepKind == OMPC_DEPEND_sink ||
+       ((LangOpts.OpenMP < 50 ||
+         DSAStack->getCurrentDirective() == OMPD_depobj) &&
+        DepKind == OMPC_DEPEND_depobj))) {
+    SmallVector<unsigned, 6> Except = {OMPC_DEPEND_source, OMPC_DEPEND_sink,
+                                       OMPC_DEPEND_outallmemory,
+                                       OMPC_DEPEND_inoutallmemory};
+    if (LangOpts.OpenMP < 50 || DSAStack->getCurrentDirective() == OMPD_depobj)
+      Except.push_back(OMPC_DEPEND_depobj);
+    if (LangOpts.OpenMP < 51)
+      Except.push_back(OMPC_DEPEND_inoutset);
+    std::string Expected = (LangOpts.OpenMP >= 50 && !DepModifier)
+                               ? "depend modifier(iterator) or "
+                               : "";
+    Diag(DepLoc, diag::err_omp_unexpected_clause_value)
+        << Expected + getListOfPossibleValues(OMPC_depend, /*First=*/0,
+                                              /*Last=*/OMPC_DEPEND_unknown,
+                                              Except)
+        << getOpenMPClauseName(OMPC_depend);
+    return nullptr;
+  }
+  if (DepModifier &&
+      (DepKind == OMPC_DEPEND_source || DepKind == OMPC_DEPEND_sink)) {
+    Diag(DepModifier->getExprLoc(),
+         diag::err_omp_depend_sink_source_with_modifier);
+    return nullptr;
+  }
+  if (DepModifier &&
+      !DepModifier->getType()->isSpecificBuiltinType(BuiltinType::OMPIterator))
+    Diag(DepModifier->getExprLoc(), diag::err_omp_depend_modifier_not_iterator);
+
+  SmallVector<Expr *, 8> Vars;
+  DSAStackTy::OperatorOffsetTy OpsOffs;
+  llvm::APSInt TotalDepCount(/*BitWidth=*/32);
+
+  if (DepKind == OMPC_DEPEND_sink || DepKind == OMPC_DEPEND_source) {
+    DoacrossDataInfoTy VarOffset = ProcessOpenMPDoacrossClauseCommon(
+        *this, DepKind == OMPC_DEPEND_source, VarList, DSAStack, EndLoc);
+    Vars = VarOffset.Vars;
+    OpsOffs = VarOffset.OpsOffs;
+    TotalDepCount = VarOffset.TotalDepCount;
+  } else {
+    for (Expr *RefExpr : VarList) {
+      assert(RefExpr && "NULL expr in OpenMP shared clause.");
+      if (isa<DependentScopeDeclRefExpr>(RefExpr)) {
+        // It will be analyzed later.
+        Vars.push_back(RefExpr);
+        continue;
+      }
+
+      SourceLocation ELoc = RefExpr->getExprLoc();
+      Expr *SimpleExpr = RefExpr->IgnoreParenCasts();
+      if (DepKind != OMPC_DEPEND_sink && DepKind != OMPC_DEPEND_source) {
+        bool OMPDependTFound = LangOpts.OpenMP >= 50;
+        if (OMPDependTFound)
+          OMPDependTFound = findOMPDependT(*this, StartLoc, DSAStack,
+                                           DepKind == OMPC_DEPEND_depobj);
+        if (DepKind == OMPC_DEPEND_depobj) {
+          // OpenMP 5.0, 2.17.11 depend Clause, Restrictions, C/C++
+          // List items used in depend clauses with the depobj dependence type
+          // must be expressions of the omp_depend_t type.
+          if (!RefExpr->isValueDependent() && !RefExpr->isTypeDependent() &&
+              !RefExpr->isInstantiationDependent() &&
+              !RefExpr->containsUnexpandedParameterPack() &&
+              (OMPDependTFound &&
+               !Context.hasSameUnqualifiedType(DSAStack->getOMPDependT(),
+                                               RefExpr->getType()))) {
+            Diag(ELoc, diag::err_omp_expected_omp_depend_t_lvalue)
+                << 0 << RefExpr->getType() << RefExpr->getSourceRange();
             continue;
           }
-        }
+          if (!RefExpr->isLValue()) {
+            Diag(ELoc, diag::err_omp_expected_omp_depend_t_lvalue)
+                << 1 << RefExpr->getType() << RefExpr->getSourceRange();
+            continue;
+          }
+        } else {
+          // OpenMP 5.0 [2.17.11, Restrictions]
+          // List items used in depend clauses cannot be zero-length array
+          // sections.
+          QualType ExprTy = RefExpr->getType().getNonReferenceType();
+          const auto *OASE = dyn_cast<OMPArraySectionExpr>(SimpleExpr);
+          if (OASE) {
+            QualType BaseType =
+                OMPArraySectionExpr::getBaseOriginalType(OASE->getBase());
+            if (const auto *ATy = BaseType->getAsArrayTypeUnsafe())
+              ExprTy = ATy->getElementType();
+            else
+              ExprTy = BaseType->getPointeeType();
+            ExprTy = ExprTy.getNonReferenceType();
+            const Expr *Length = OASE->getLength();
+            Expr::EvalResult Result;
+            if (Length && !Length->isValueDependent() &&
+                Length->EvaluateAsInt(Result, Context) &&
+                Result.Val.getInt().isZero()) {
+              Diag(ELoc,
+                   diag::err_omp_depend_zero_length_array_section_not_allowed)
+                  << SimpleExpr->getSourceRange();
+              continue;
+            }
+          }
 
-        // OpenMP 5.0, 2.17.11 depend Clause, Restrictions, C/C++
-        // List items used in depend clauses with the in, out, inout,
-        // inoutset, or mutexinoutset dependence types cannot be
-        // expressions of the omp_depend_t type.
-        if (!RefExpr->isValueDependent() && !RefExpr->isTypeDependent() &&
-            !RefExpr->isInstantiationDependent() &&
-            !RefExpr->containsUnexpandedParameterPack() &&
-            (!RefExpr->IgnoreParenImpCasts()->isLValue() ||
-             (OMPDependTFound &&
-              DSAStack->getOMPDependT().getTypePtr() == ExprTy.getTypePtr()))) {
-          Diag(ELoc, diag::err_omp_expected_addressable_lvalue_or_array_item)
-              << (LangOpts.OpenMP >= 50 ? 1 : 0)
-              << (LangOpts.OpenMP >= 50 ? 1 : 0) << RefExpr->getSourceRange();
-          continue;
-        }
+          // OpenMP 5.0, 2.17.11 depend Clause, Restrictions, C/C++
+          // List items used in depend clauses with the in, out, inout,
+          // inoutset, or mutexinoutset dependence types cannot be
+          // expressions of the omp_depend_t type.
+          if (!RefExpr->isValueDependent() && !RefExpr->isTypeDependent() &&
+              !RefExpr->isInstantiationDependent() &&
+              !RefExpr->containsUnexpandedParameterPack() &&
+              (!RefExpr->IgnoreParenImpCasts()->isLValue() ||
+               (OMPDependTFound && DSAStack->getOMPDependT().getTypePtr() ==
+                                       ExprTy.getTypePtr()))) {
+            Diag(ELoc, diag::err_omp_expected_addressable_lvalue_or_array_item)
+                << (LangOpts.OpenMP >= 50 ? 1 : 0)
+                << (LangOpts.OpenMP >= 50 ? 1 : 0) << RefExpr->getSourceRange();
+            continue;
+          }
 
-        auto *ASE = dyn_cast<ArraySubscriptExpr>(SimpleExpr);
-        if (ASE && !ASE->getBase()->isTypeDependent() &&
-            !ASE->getBase()->getType().getNonReferenceType()->isPointerType() &&
-            !ASE->getBase()->getType().getNonReferenceType()->isArrayType()) {
-          Diag(ELoc, diag::err_omp_expected_addressable_lvalue_or_array_item)
-              << (LangOpts.OpenMP >= 50 ? 1 : 0)
-              << (LangOpts.OpenMP >= 50 ? 1 : 0) << RefExpr->getSourceRange();
-          continue;
-        }
+          auto *ASE = dyn_cast<ArraySubscriptExpr>(SimpleExpr);
+          if (ASE && !ASE->getBase()->isTypeDependent() &&
+              !ASE->getBase()
+                   ->getType()
+                   .getNonReferenceType()
+                   ->isPointerType() &&
+              !ASE->getBase()->getType().getNonReferenceType()->isArrayType()) {
+            Diag(ELoc, diag::err_omp_expected_addressable_lvalue_or_array_item)
+                << (LangOpts.OpenMP >= 50 ? 1 : 0)
+                << (LangOpts.OpenMP >= 50 ? 1 : 0) << RefExpr->getSourceRange();
+            continue;
+          }
 
-        ExprResult Res;
-        {
-          Sema::TentativeAnalysisScope Trap(*this);
-          Res = CreateBuiltinUnaryOp(ELoc, UO_AddrOf,
-                                     RefExpr->IgnoreParenImpCasts());
-        }
-        if (!Res.isUsable() && !isa<OMPArraySectionExpr>(SimpleExpr) &&
-            !isa<OMPArrayShapingExpr>(SimpleExpr)) {
-          Diag(ELoc, diag::err_omp_expected_addressable_lvalue_or_array_item)
-              << (LangOpts.OpenMP >= 50 ? 1 : 0)
-              << (LangOpts.OpenMP >= 50 ? 1 : 0) << RefExpr->getSourceRange();
-          continue;
+          ExprResult Res;
+          {
+            Sema::TentativeAnalysisScope Trap(*this);
+            Res = CreateBuiltinUnaryOp(ELoc, UO_AddrOf,
+                                       RefExpr->IgnoreParenImpCasts());
+          }
+          if (!Res.isUsable() && !isa<OMPArraySectionExpr>(SimpleExpr) &&
+              !isa<OMPArrayShapingExpr>(SimpleExpr)) {
+            Diag(ELoc, diag::err_omp_expected_addressable_lvalue_or_array_item)
+                << (LangOpts.OpenMP >= 50 ? 1 : 0)
+                << (LangOpts.OpenMP >= 50 ? 1 : 0) << RefExpr->getSourceRange();
+            continue;
+          }
         }
       }
+      Vars.push_back(RefExpr->IgnoreParenImpCasts());
     }
-    Vars.push_back(RefExpr->IgnoreParenImpCasts());
   }
 
-  if (!CurContext->isDependentContext() && DepKind == OMPC_DEPEND_sink &&
-      TotalDepCount > VarList.size() &&
-      DSAStack->getParentOrderedRegionParam().first &&
-      DSAStack->getParentLoopControlVariable(VarList.size() + 1)) {
-    Diag(EndLoc, diag::err_omp_depend_sink_expected_loop_iteration)
-        << 1 << DSAStack->getParentLoopControlVariable(VarList.size() + 1);
-  }
   if (DepKind != OMPC_DEPEND_source && DepKind != OMPC_DEPEND_sink &&
       DepKind != OMPC_DEPEND_outallmemory &&
       DepKind != OMPC_DEPEND_inoutallmemory && Vars.empty())
@@ -23947,3 +24033,31 @@ OMPClause *Sema::ActOnOpenMPXDynCGroupMemClause(Expr *Size,
   return new (Context) OMPXDynCGroupMemClause(
       ValExpr, HelperValStmt, CaptureRegion, StartLoc, LParenLoc, EndLoc);
 }
+
+OMPClause *Sema::ActOnOpenMPDoacrossClause(
+    OpenMPDoacrossClauseModifier DepType, SourceLocation DepLoc,
+    SourceLocation ColonLoc, ArrayRef<Expr *> VarList, SourceLocation StartLoc,
+    SourceLocation LParenLoc, SourceLocation EndLoc) {
+
+  if (DSAStack->getCurrentDirective() == OMPD_ordered &&
+      DepType != OMPC_DOACROSS_source && DepType != OMPC_DOACROSS_sink) {
+    Diag(DepLoc, diag::err_omp_unexpected_clause_value)
+        << "'source' or 'sink'" << getOpenMPClauseName(OMPC_doacross);
+    return nullptr;
+  }
+
+  SmallVector<Expr *, 8> Vars;
+  DSAStackTy::OperatorOffsetTy OpsOffs;
+  llvm::APSInt TotalDepCount(/*BitWidth=*/32);
+  DoacrossDataInfoTy VarOffset = ProcessOpenMPDoacrossClauseCommon(
+      *this, DepType == OMPC_DOACROSS_source, VarList, DSAStack, EndLoc);
+  Vars = VarOffset.Vars;
+  OpsOffs = VarOffset.OpsOffs;
+  TotalDepCount = VarOffset.TotalDepCount;
+  auto *C = OMPDoacrossClause::Create(Context, StartLoc, LParenLoc, EndLoc,
+                                      DepType, DepLoc, ColonLoc, Vars,
+                                      TotalDepCount.getZExtValue());
+  if (DSAStack->isParentOrderedRegion())
+    DSAStack->addDoacrossDependClause(C, OpsOffs);
+  return C;
+}

diff  --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index f0401f080dd9f8..10b3587885e39f 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -2422,6 +2422,19 @@ class TreeTransform {
     return getSema().ActOnOpenMPMessageClause(MS, StartLoc, LParenLoc, EndLoc);
   }
 
+  /// Build a new OpenMP 'doacross' clause.
+  ///
+  /// By default, performs semantic analysis to build the new OpenMP clause.
+  /// Subclasses may override this routine to provide 
diff erent behavior.
+  OMPClause *
+  RebuildOMPDoacrossClause(OpenMPDoacrossClauseModifier DepType,
+                           SourceLocation DepLoc, SourceLocation ColonLoc,
+                           ArrayRef<Expr *> VarList, SourceLocation StartLoc,
+                           SourceLocation LParenLoc, SourceLocation EndLoc) {
+    return getSema().ActOnOpenMPDoacrossClause(
+        DepType, DepLoc, ColonLoc, VarList, StartLoc, LParenLoc, EndLoc);
+  }
+
   /// Rebuild the operand to an Objective-C \@synchronized statement.
   ///
   /// By default, performs semantic analysis to build the new statement.
@@ -10727,6 +10740,22 @@ OMPClause *TreeTransform<Derived>::TransformOMPXDynCGroupMemClause(
       Size.get(), C->getBeginLoc(), C->getLParenLoc(), C->getEndLoc());
 }
 
+template <typename Derived>
+OMPClause *
+TreeTransform<Derived>::TransformOMPDoacrossClause(OMPDoacrossClause *C) {
+  llvm::SmallVector<Expr *, 16> Vars;
+  Vars.reserve(C->varlist_size());
+  for (auto *VE : C->varlists()) {
+    ExprResult EVar = getDerived().TransformExpr(cast<Expr>(VE));
+    if (EVar.isInvalid())
+      return nullptr;
+    Vars.push_back(EVar.get());
+  }
+  return getDerived().RebuildOMPDoacrossClause(
+      C->getDependenceType(), C->getDependenceLoc(), C->getColonLoc(), Vars,
+      C->getBeginLoc(), C->getLParenLoc(), C->getEndLoc());
+}
+
 //===----------------------------------------------------------------------===//
 // Expression transformation
 //===----------------------------------------------------------------------===//

diff  --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index cba6791783e8b4..a9f25ec2ecb75b 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -10362,6 +10362,12 @@ OMPClause *OMPClauseReader::readClause() {
   case llvm::omp::OMPC_ompx_dyn_cgroup_mem:
     C = new (Context) OMPXDynCGroupMemClause();
     break;
+  case llvm::omp::OMPC_doacross: {
+    unsigned NumVars = Record.readInt();
+    unsigned NumLoops = Record.readInt();
+    C = OMPDoacrossClause::CreateEmpty(Context, NumVars, NumLoops);
+    break;
+  }
 #define OMP_CLAUSE_NO_CLASS(Enum, Str)                                         \
   case llvm::omp::Enum:                                                        \
     break;
@@ -11438,6 +11444,22 @@ void OMPClauseReader::VisitOMPXDynCGroupMemClause(OMPXDynCGroupMemClause *C) {
   C->setLParenLoc(Record.readSourceLocation());
 }
 
+void OMPClauseReader::VisitOMPDoacrossClause(OMPDoacrossClause *C) {
+  C->setLParenLoc(Record.readSourceLocation());
+  C->setDependenceType(
+      static_cast<OpenMPDoacrossClauseModifier>(Record.readInt()));
+  C->setDependenceLoc(Record.readSourceLocation());
+  C->setColonLoc(Record.readSourceLocation());
+  unsigned NumVars = C->varlist_size();
+  SmallVector<Expr *, 16> Vars;
+  Vars.reserve(NumVars);
+  for (unsigned I = 0; I != NumVars; ++I)
+    Vars.push_back(Record.readSubExpr());
+  C->setVarRefs(Vars);
+  for (unsigned I = 0, E = C->getNumLoops(); I < E; ++I)
+    C->setLoopData(I, Record.readSubExpr());
+}
+
 OMPTraitInfo *ASTRecordReader::readOMPTraitInfo() {
   OMPTraitInfo &TI = getContext().getNewOMPTraitInfo();
   TI.Sets.resize(readUInt32());

diff  --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index ff5bab7c99f788..ca0db085d94cc9 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -7155,6 +7155,19 @@ void OMPClauseWriter::VisitOMPXDynCGroupMemClause(OMPXDynCGroupMemClause *C) {
   Record.AddSourceLocation(C->getLParenLoc());
 }
 
+void OMPClauseWriter::VisitOMPDoacrossClause(OMPDoacrossClause *C) {
+  Record.push_back(C->varlist_size());
+  Record.push_back(C->getNumLoops());
+  Record.AddSourceLocation(C->getLParenLoc());
+  Record.push_back(C->getDependenceType());
+  Record.AddSourceLocation(C->getDependenceLoc());
+  Record.AddSourceLocation(C->getColonLoc());
+  for (auto *VE : C->varlists())
+    Record.AddStmt(VE);
+  for (unsigned I = 0, E = C->getNumLoops(); I < E; ++I)
+    Record.AddStmt(C->getLoopData(I));
+}
+
 void ASTRecordWriter::writeOMPTraitInfo(const OMPTraitInfo *TI) {
   writeUInt32(TI->Sets.size());
   for (const auto &Set : TI->Sets) {

diff  --git a/clang/test/OpenMP/ordered_ast_print.cpp b/clang/test/OpenMP/ordered_ast_print.cpp
index f36afab8b2075c..298d52132e9744 100644
--- a/clang/test/OpenMP/ordered_ast_print.cpp
+++ b/clang/test/OpenMP/ordered_ast_print.cpp
@@ -1,10 +1,14 @@
-// RUN: %clang_cc1 -verify -fopenmp -ast-print %s | FileCheck %s
+// RUN: %clang_cc1 -verify -fopenmp -ast-print %s | FileCheck -check-prefixes CHECK,OMP51 %s
 // RUN: %clang_cc1 -fopenmp -x c++ -std=c++11 -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck %s
+// RUN: %clang_cc1 -fopenmp -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck -check-prefixes CHECK,OMP51 %s
 
-// RUN: %clang_cc1 -verify -fopenmp-simd -ast-print %s | FileCheck %s
+// RUN: %clang_cc1 -verify -fopenmp-version=52 -fopenmp -ast-print %s | FileCheck -check-prefixes CHECK,OMP52 %s
+// RUN: %clang_cc1 -fopenmp -fopenmp-version=52 -x c++ -std=c++11 -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -fopenmp-version=52 -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck -check-prefixes CHECK,OMP52 %s
+
+// RUN: %clang_cc1 -verify -fopenmp-simd -ast-print %s | FileCheck -check-prefixes CHECK,OMP51 %s
 // RUN: %clang_cc1 -fopenmp-simd -x c++ -std=c++11 -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp-simd -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck %s
+// RUN: %clang_cc1 -fopenmp-simd -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck -check-prefixes CHECK,OMP51 %s
 // expected-no-diagnostics
 
 #ifndef HEADER
@@ -48,8 +52,13 @@ T tmain (T argc) {
   }
   #pragma omp parallel for ordered(1)
   for (int i =0 ; i < argc; ++i) {
+#if _OPENMP >= 202111
+  #pragma omp ordered doacross(source:)
+  #pragma omp ordered doacross(sink:i+N)
+#else
   #pragma omp ordered depend(source)
   #pragma omp ordered depend(sink:i+N)
+#endif
     a = 2;
   }
   return (0);
@@ -88,8 +97,13 @@ T tmain (T argc) {
 // CHECK-NEXT: }
 // CHECK-NEXT: #pragma omp parallel for ordered(1)
 // CHECK-NEXT: for (int i = 0; i < argc; ++i) {
-// CHECK-NEXT: #pragma omp ordered depend(source)
-// CHECK-NEXT: #pragma omp ordered depend(sink : i + N)
+#if _OPENMP >= 202111
+// OMP52: #pragma omp ordered doacross(source:)
+// OMP52-NEXT: #pragma omp ordered doacross(sink: i + N)
+#else
+// OMP51: #pragma omp ordered depend(source)
+// OMP51-NEXT: #pragma omp ordered depend(sink : i + N)
+#endif
 // CHECK-NEXT: a = 2;
 // CHECK-NEXT: }
 // CHECK: static int a;
@@ -125,8 +139,13 @@ T tmain (T argc) {
 // CHECK-NEXT: }
 // CHECK-NEXT: #pragma omp parallel for ordered(1)
 // CHECK-NEXT: for (int i = 0; i < argc; ++i) {
-// CHECK-NEXT: #pragma omp ordered depend(source)
-// CHECK-NEXT: #pragma omp ordered depend(sink : i + 3)
+#if _OPENMP >= 202111
+// OMP52: #pragma omp ordered doacross(source:)
+// OMP52-NEXT: #pragma omp ordered doacross(sink: i + 3)
+#else
+// OMP51: #pragma omp ordered depend(source)
+// OMP51-NEXT: #pragma omp ordered depend(sink : i + 3)
+#endif
 // CHECK-NEXT: a = 2;
 // CHECK-NEXT: }
 
@@ -167,8 +186,13 @@ int main (int argc, char **argv) {
   }
   #pragma omp parallel for ordered(1)
   for (int i =0 ; i < argc; ++i) {
+#if _OPENMP >= 202111
+  #pragma omp ordered doacross(source:)
+  #pragma omp ordered doacross(sink: i - 5)
+#else
   #pragma omp ordered depend(source)
   #pragma omp ordered depend(sink: i - 5)
+#endif
     a = 2;
   }
 // CHECK-NEXT: #pragma omp for ordered
@@ -203,8 +227,13 @@ int main (int argc, char **argv) {
 // CHECK-NEXT: }
 // CHECK-NEXT: #pragma omp parallel for ordered(1)
 // CHECK-NEXT: for (int i = 0; i < argc; ++i) {
-// CHECK-NEXT: #pragma omp ordered depend(source)
-// CHECK-NEXT: #pragma omp ordered depend(sink : i - 5)
+#if _OPENMP >= 202111
+// OMP52: #pragma omp ordered doacross(source:)
+// OMP52-NEXT: #pragma omp ordered doacross(sink: i - 5)
+#else
+// OMP51: #pragma omp ordered depend(source)
+// OMP51-NEXT: #pragma omp ordered depend(sink : i - 5)
+#endif
 // CHECK-NEXT: a = 2;
 // CHECK-NEXT: }
   return tmain<int, 3>(argc);

diff  --git a/clang/test/OpenMP/ordered_messages.cpp b/clang/test/OpenMP/ordered_messages.cpp
index 8a3a86443eb8c8..3711693688c519 100644
--- a/clang/test/OpenMP/ordered_messages.cpp
+++ b/clang/test/OpenMP/ordered_messages.cpp
@@ -1,6 +1,7 @@
 // RUN: %clang_cc1 -verify -fopenmp -ferror-limit 100 -o - %s -Wuninitialized
 // RUN: %clang_cc1 -verify -fopenmp -ferror-limit 100 -std=c++98 -o - %s -Wuninitialized
 // RUN: %clang_cc1 -verify -fopenmp -ferror-limit 100 -std=c++11 -o - %s -Wuninitialized
+// RUN: %clang_cc1 -verify=expected,omp52 -fopenmp -fopenmp-version=52 -ferror-limit 100 -o - %s -Wuninitialized
 
 // RUN: %clang_cc1 -verify -fopenmp-simd -ferror-limit 100 -o - %s -Wuninitialized
 // RUN: %clang_cc1 -verify -fopenmp-simd -ferror-limit 100 -std=c++98 -o - %s -Wuninitialized
@@ -135,12 +136,48 @@ T foo() {
   }
 #pragma omp parallel for ordered
   for (int i = 0; i < 10; ++i) {
+#if _OPENMP >= 202111
+    #pragma omp ordered doacross(source:) // omp52-error {{'ordered' directive with 'doacross' clause cannot be closely nested inside ordered region without specified parameter}}
+    #pragma omp ordered doacross(sink : i) // omp52-error {{'ordered' directive with 'doacross' clause cannot be closely nested inside ordered region without specified parameter}}
+#else
     #pragma omp ordered depend(source) // expected-error {{'ordered' directive with 'depend' clause cannot be closely nested inside ordered region without specified parameter}}
     #pragma omp ordered depend(sink : i) // expected-error {{'ordered' directive with 'depend' clause cannot be closely nested inside ordered region without specified parameter}}
+#endif
   }
 #pragma omp parallel for ordered(2) // expected-note 3 {{'ordered' clause with specified parameter}}
   for (int i = 0; i < 10; ++i) {
     for (int j = 0; j < 10; ++j) {
+#if _OPENMP >= 202111
+#pragma omp ordered doacross // omp52-error {{expected '(' after 'doacross'}} omp52-error {{'ordered' directive without any clauses cannot be closely nested inside ordered region with specified parameter}}
+#pragma omp ordered doacross( // omp52-error {{expected ')'}} omp52-error {{expected 'source' or 'sink' in OpenMP clause 'doacross'}} omp52-error {{'ordered' directive without any clauses cannot be closely nested inside ordered region with specified parameter}} omp52-warning {{missing ':' or ')' after dependence-type - ignoring}} omp52-note {{to match this '('}}
+#pragma omp ordered doacross(source // omp52-warning {{missing ':' or ')' after dependence-type - ignoring}} omp52-error {{expected ')'}} omp52-note {{to match this '('}}
+#pragma omp ordered doacross(sink // omp52-error {{expected expression}} omp52-warning {{missing ':' or ')' after dependence-type - ignoring}} omp52-error {{expected ')'}} omp52-note {{to match this '('}} omp52-error {{expected 'i' loop iteration variable}}
+#pragma omp ordered doacross(sink : // omp52-error {{expected ')'}} omp52-note {{to match this '('}} omp52-error {{expected expression}} omp52-error {{expected 'i' loop iteration variable}}
+#pragma omp ordered doacross(sink : i // omp52-error {{expected ')'}} omp52-note {{to match this '('}} omp52-error {{expected 'j' loop iteration variable}}
+#pragma omp ordered doacross(sink : i) // omp52-error {{expected 'j' loop iteration variable}}
+#pragma omp ordered doacross(source:)
+                           if (i == j)
+#pragma omp ordered doacross(source:) // omp52-error {{'#pragma omp ordered' with 'doacross' clause cannot be an immediate substatement}}
+                             ;
+                           if (i == j)
+#pragma omp ordered doacross(sink : i, j) // omp52-error {{'#pragma omp ordered' with 'doacross' clause cannot be an immediate substatement}}
+                             ;
+#pragma omp ordered doacross(source:) threads // omp52-error {{'doacross' clauses cannot be mixed with 'threads' clause}}
+#pragma omp ordered simd doacross(source:) // omp52-error {{'doacross' clauses cannot be mixed with 'simd' clause}}
+#pragma omp ordered doacross(source:) doacross(source:) // omp52-error {{directive '#pragma omp ordered' cannot contain more than one 'doacross' clause with 'source' dependence}}
+#pragma omp ordered doacross(in : i) // omp52-error {{expected 'source' or 'sink' in OpenMP clause 'doacross'}} omp52-error {{'ordered' directive without any clauses cannot be closely nested inside ordered region with specified parameter}}
+#pragma omp ordered doacross(sink : i, j)
+#pragma omp ordered doacross(sink : j, i) // omp52-error {{expected 'i' loop iteration variable}} omp52-error {{expected 'j' loop iteration variable}}
+#pragma omp ordered doacross(sink : i, j, k) // omp52-error {{unexpected expression: number of expressions is larger than the number of associated loops}}
+#pragma omp ordered doacross(sink : i+foo(), j/4) // omp52-error {{integral constant expression}} omp52-error {{expected '+' or '-' operation}}
+#if __cplusplus >= 201103L
+// omp52-note at -2 {{non-constexpr function 'foo' cannot be used in a constant expression}}
+#endif
+#pragma omp ordered doacross(sink : i*0, j-4)// omp52-error {{expected '+' or '-' operation}}
+#pragma omp ordered doacross(sink : i-0, j+sizeof(T)) doacross(sink : i-0, j+sizeof(T))
+#pragma omp ordered doacross(sink : i-0, j+sizeof(T)) doacross(source:) // omp52-error {{'doacross(source)' clause cannot be mixed with 'doacross(sink:vec)' clauses}}
+#pragma omp ordered doacross(source:) doacross(sink : i-0, j+sizeof(T)) // omp52-error {{'doacross(sink:vec)' clauses cannot be mixed with 'doacross(source)' clause}}
+#else
 #pragma omp ordered depend // expected-error {{expected '(' after 'depend'}} expected-error {{'ordered' directive without any clauses cannot be closely nested inside ordered region with specified parameter}}
 #pragma omp ordered depend( // expected-error {{expected ')'}} expected-error {{expected 'source' or 'sink' in OpenMP clause 'depend'}} expected-error {{'ordered' directive without any clauses cannot be closely nested inside ordered region with specified parameter}} expected-warning {{missing ':' or ')' after dependency type - ignoring}} expected-note {{to match this '('}}
 #pragma omp ordered depend(source // expected-error {{expected ')'}} expected-note {{to match this '('}}
@@ -170,10 +207,14 @@ T foo() {
 #pragma omp ordered depend(sink : i-0, j+sizeof(T)) depend(sink : i-0, j+sizeof(T))
 #pragma omp ordered depend(sink : i-0, j+sizeof(T)) depend(source) // expected-error {{'depend(source)' clause cannot be mixed with 'depend(sink:vec)' clauses}}
 #pragma omp ordered depend(source) depend(sink : i-0, j+sizeof(T)) // expected-error {{'depend(sink:vec)' clauses cannot be mixed with 'depend(source)' clause}}
+#endif
     }
   }
+#if _OPENMP >= 202111
+#else
 #pragma omp ordered depend(source) // expected-error {{'ordered' directive with 'depend' clause cannot be closely nested inside ordered region without specified parameter}}
 #pragma omp ordered depend(sink:k) // expected-error {{'ordered' directive with 'depend' clause cannot be closely nested inside ordered region without specified parameter}}
+#endif
   return T();
 }
 
@@ -272,12 +313,46 @@ int k;
   }
 #pragma omp parallel for ordered
   for (int i = 0; i < 10; ++i) {
+#if _OPENMP >= 202111
+#else
     #pragma omp ordered depend(source) // expected-error {{'ordered' directive with 'depend' clause cannot be closely nested inside ordered region without specified parameter}}
     #pragma omp ordered depend(sink : i) // expected-error {{'ordered' directive with 'depend' clause cannot be closely nested inside ordered region without specified parameter}}
+#endif
   }
 #pragma omp parallel for ordered(2) // expected-note 3 {{'ordered' clause with specified parameter}}
   for (int i = 0; i < 10; ++i) {
     for (int j = 0; j < 10; ++j) {
+#if _OPENMP >= 202111
+#pragma omp ordered doacross // omp52-error {{expected '(' after 'doacross'}} omp52-error {{'ordered' directive without any clauses cannot be closely nested inside ordered region with specified parameter}}
+#pragma omp ordered doacross( // omp52-error {{expected ')'}} omp52-error {{expected 'source' or 'sink' in OpenMP clause 'doacross'}} omp52-error {{'ordered' directive without any clauses cannot be closely nested inside ordered region with specified parameter}} omp52-warning {{missing ':' or ')' after dependence-type - ignoring}} omp52-note {{to match this '('}}
+#pragma omp ordered doacross(source // omp52-warning {{missing ':' or ')' after dependence-type - ignoring}} omp52-error {{expected ')'}} omp52-note {{to match this '('}}
+#pragma omp ordered doacross(sink // omp52-error {{expected expression}} omp52-warning {{missing ':' or ')' after dependence-type - ignoring}} omp52-error {{expected ')'}} omp52-note {{to match this '('}} omp52-error {{expected 'i' loop iteration variable}}
+#pragma omp ordered doacross(sink : // omp52-error {{expected ')'}} omp52-note {{to match this '('}} omp52-error {{expected expression}} omp52-error {{expected 'i' loop iteration variable}}
+#pragma omp ordered doacross(sink : i // omp52-error {{expected ')'}} omp52-note {{to match this '('}} omp52-error {{expected 'j' loop iteration variable}}
+#pragma omp ordered doacross(sink : i) // omp52-error {{expected 'j' loop iteration variable}}
+#pragma omp ordered doacross(source:)
+                           if (i == j)
+#pragma omp ordered doacross(source:) // omp52-error {{'#pragma omp ordered' with 'doacross' clause cannot be an immediate substatement}}
+                             ;
+                           if (i == j)
+#pragma omp ordered doacross(sink : i, j) // omp52-error {{'#pragma omp ordered' with 'doacross' clause cannot be an immediate substatement}}
+                             ;
+#pragma omp ordered doacross(source:) threads // omp52-error {{'doacross' clauses cannot be mixed with 'threads' clause}}
+#pragma omp ordered simd doacross(source:) // omp52-error {{'doacross' clauses cannot be mixed with 'simd' clause}}
+#pragma omp ordered doacross(source:) doacross(source:) // omp52-error {{directive '#pragma omp ordered' cannot contain more than one 'doacross' clause with 'source' dependence}}
+#pragma omp ordered doacross(in : i) // omp52-error {{expected 'source' or 'sink' in OpenMP clause 'doacross'}} omp52-error {{'ordered' directive without any clauses cannot be closely nested inside ordered region with specified parameter}}
+#pragma omp ordered doacross(sink : i, j) allocate(i) // omp52-error {{unexpected OpenMP clause 'allocate' in directive '#pragma omp ordered'}}
+#pragma omp ordered doacross(sink : j, i) // omp52-error {{expected 'i' loop iteration variable}} omp52-error {{expected 'j' loop iteration variable}}
+#pragma omp ordered doacross(sink : i, j, k) // omp52-error {{unexpected expression: number of expressions is larger than the number of associated loops}}
+#pragma omp ordered doacross(sink : i+foo(), j/4) // omp52-error {{integral constant expression}} omp52-error {{expected '+' or '-' operation}}
+#if __cplusplus >= 201103L
+// omp52-note at -2 {{non-constexpr function 'foo' cannot be used in a constant expression}}
+#endif
+#pragma omp ordered doacross(sink : i*0, j-4)// omp52-error {{expected '+' or '-' operation}}
+#pragma omp ordered doacross(sink : i-0, j+sizeof(int)) doacross(sink : i-0, j+sizeof(int))
+#pragma omp ordered doacross(sink : i-0, j+sizeof(int)) doacross(source:) // omp52-error {{'doacross(source)' clause cannot be mixed with 'doacross(sink:vec)' clauses}}
+#pragma omp ordered doacross(source:) doacross(sink : i-0, j+sizeof(int)) // omp52-error {{'doacross(sink:vec)' clauses cannot be mixed with 'doacross(source)' clause}}
+#else
 #pragma omp ordered depend // expected-error {{expected '(' after 'depend'}} expected-error {{'ordered' directive without any clauses cannot be closely nested inside ordered region with specified parameter}}
 #pragma omp ordered depend( // expected-error {{expected ')'}} expected-error {{expected 'source' or 'sink' in OpenMP clause 'depend'}} expected-error {{'ordered' directive without any clauses cannot be closely nested inside ordered region with specified parameter}} expected-warning {{missing ':' or ')' after dependency type - ignoring}} expected-note {{to match this '('}}
 #pragma omp ordered depend(source // expected-error {{expected ')'}} expected-note {{to match this '('}}
@@ -307,14 +382,21 @@ int k;
 #pragma omp ordered depend(sink : i-0, j+sizeof(int)) depend(sink : i-0, j+sizeof(int))
 #pragma omp ordered depend(sink : i-0, j+sizeof(int)) depend(source) // expected-error {{'depend(source)' clause cannot be mixed with 'depend(sink:vec)' clauses}}
 #pragma omp ordered depend(source) depend(sink : i-0, j+sizeof(int)) // expected-error {{'depend(sink:vec)' clauses cannot be mixed with 'depend(source)' clause}}
+#endif
     }
   }
 
 #pragma omp for ordered(2) // expected-note {{as specified in 'ordered' clause}}
   for (int i = 0; i < 10; ++i) { // expected-error {{expected 2 for loops after '#pragma omp for', but found only 1}}
+#if _OPENMP >= 202111
+#pragma omp ordered doacross(sink : i)
+    int j;
+#pragma omp ordered doacross(sink : i, j) // omp52-error {{expected loop iteration variable}}
+#else
 #pragma omp ordered depend(sink : i)
     int j;
 #pragma omp ordered depend(sink : i, j) // expected-error {{expected loop iteration variable}}
+#endif
     foo();
   }
 

diff  --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
index 25118c702f1be6..fb6cc96cac55d7 100644
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -2717,6 +2717,9 @@ void OMPClauseEnqueue::VisitOMPXDynCGroupMemClause(
   VisitOMPClauseWithPreInit(C);
   Visitor->AddStmt(C->getSize());
 }
+void OMPClauseEnqueue::VisitOMPDoacrossClause(const OMPDoacrossClause *C) {
+  VisitOMPClauseList(C);
+}
 
 } // namespace
 

diff  --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
index eb8de20a6b8ba0..c84ad3ffcbbdc2 100644
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -1937,6 +1937,7 @@ CHECK_SIMPLE_CLAUSE(Bind, OMPC_bind)
 CHECK_SIMPLE_CLAUSE(Align, OMPC_align)
 CHECK_SIMPLE_CLAUSE(Compare, OMPC_compare)
 CHECK_SIMPLE_CLAUSE(CancellationConstructType, OMPC_cancellation_construct_type)
+CHECK_SIMPLE_CLAUSE(Doacross, OMPC_doacross)
 
 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
index 0f8a9d58acc439..c67b54acc47c0d 100644
--- a/llvm/include/llvm/Frontend/OpenMP/OMP.td
+++ b/llvm/include/llvm/Frontend/OpenMP/OMP.td
@@ -444,6 +444,10 @@ def OMPC_OMPX_DynCGroupMem : Clause<"ompx_dyn_cgroup_mem"> {
   let flangClass = "ScalarIntExpr";
 }
 
+def OMPC_Doacross : Clause<"doacross"> {
+  let clangClass = "OMPDoacrossClause";
+}
+
 //===----------------------------------------------------------------------===//
 // Definition of OpenMP directives
 //===----------------------------------------------------------------------===//
@@ -604,7 +608,8 @@ def OMP_Flush : Directive<"flush"> {
 }
 def OMP_Ordered : Directive<"ordered"> {
   let allowedClauses = [
-    VersionedClause<OMPC_Depend>
+    VersionedClause<OMPC_Depend>,
+    VersionedClause<OMPC_Doacross, 52>
   ];
   let allowedOnceClauses = [
     VersionedClause<OMPC_Threads>,


        


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