1 files changed, 1025 insertions, 442 deletions

diff --git a/contrib/llvm/tools/clang/lib/Sema/SemaOpenMP.cpp b/contrib/llvm/tools/clang/lib/Sema/SemaOpenMP.cpp
index 6060e5b75c22..36048a38b999 100644
--- a/contrib/llvm/tools/clang/lib/Sema/SemaOpenMP.cpp
+++ b/contrib/llvm/tools/clang/lib/Sema/SemaOpenMP.cpp
@@ -22,6 +22,7 @@
 #include "clang/AST/StmtCXX.h"
 #include "clang/AST/StmtOpenMP.h"
 #include "clang/AST/StmtVisitor.h"
+#include "clang/AST/TypeOrdering.h"
 #include "clang/Basic/OpenMPKinds.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
@@ -138,12 +139,15 @@ private:
     /// 'ordered' clause, the second one is true if the regions has 'ordered'
     /// clause, false otherwise.
     llvm::Optional<std::pair<const Expr *, OMPOrderedClause *>> OrderedRegion;
+    unsigned AssociatedLoops = 1;
+    const Decl *PossiblyLoopCounter = nullptr;
     bool NowaitRegion = false;
     bool CancelRegion = false;
-    unsigned AssociatedLoops = 1;
+    bool LoopStart = false;
     SourceLocation InnerTeamsRegionLoc;
     /// Reference to the taskgroup task_reduction reference expression.
     Expr *TaskgroupReductionRef = nullptr;
+    llvm::DenseSet<QualType> MappedClassesQualTypes;
     SharingMapTy(OpenMPDirectiveKind DKind, DeclarationNameInfo Name,
                  Scope *CurScope, SourceLocation Loc)
         : Directive(DKind), DirectiveName(Name), CurScope(CurScope),
@@ -162,6 +166,9 @@ private:
   OpenMPClauseKind ClauseKindMode = OMPC_unknown;
   Sema &SemaRef;
   bool ForceCapturing = false;
+  /// true if all the vaiables in the target executable directives must be
+  /// captured by reference.
+  bool ForceCaptureByReferenceInTargetExecutable = false;
   CriticalsWithHintsTy Criticals;
 
   using iterator = StackTy::const_reverse_iterator;
@@ -177,6 +184,9 @@ private:
            Stack.back().first.empty();
   }
 
+  /// Vector of previously declared requires directives
+  SmallVector<const OMPRequiresDecl *, 2> RequiresDecls;
+
 public:
   explicit DSAStackTy(Sema &S) : SemaRef(S) {}
 
@@ -190,6 +200,13 @@ public:
   bool isForceVarCapturing() const { return ForceCapturing; }
   void setForceVarCapturing(bool V) { ForceCapturing = V; }
 
+  void setForceCaptureByReferenceInTargetExecutable(bool V) {
+    ForceCaptureByReferenceInTargetExecutable = V;
+  }
+  bool isForceCaptureByReferenceInTargetExecutable() const {
+    return ForceCaptureByReferenceInTargetExecutable;
+  }
+
   void push(OpenMPDirectiveKind DKind, const DeclarationNameInfo &DirName,
             Scope *CurScope, SourceLocation Loc) {
     if (Stack.empty() ||
@@ -205,6 +222,33 @@ public:
     Stack.back().first.pop_back();
   }
 
+  /// Marks that we're started loop parsing.
+  void loopInit() {
+    assert(isOpenMPLoopDirective(getCurrentDirective()) &&
+           "Expected loop-based directive.");
+    Stack.back().first.back().LoopStart = true;
+  }
+  /// Start capturing of the variables in the loop context.
+  void loopStart() {
+    assert(isOpenMPLoopDirective(getCurrentDirective()) &&
+           "Expected loop-based directive.");
+    Stack.back().first.back().LoopStart = false;
+  }
+  /// true, if variables are captured, false otherwise.
+  bool isLoopStarted() const {
+    assert(isOpenMPLoopDirective(getCurrentDirective()) &&
+           "Expected loop-based directive.");
+    return !Stack.back().first.back().LoopStart;
+  }
+  /// Marks (or clears) declaration as possibly loop counter.
+  void resetPossibleLoopCounter(const Decl *D = nullptr) {
+    Stack.back().first.back().PossiblyLoopCounter =
+        D ? D->getCanonicalDecl() : D;
+  }
+  /// Gets the possible loop counter decl.
+  const Decl *getPossiblyLoopCunter() const {
+    return Stack.back().first.back().PossiblyLoopCounter;
+  }
   /// Start new OpenMP region stack in new non-capturing function.
   void pushFunction() {
     const FunctionScopeInfo *CurFnScope = SemaRef.getCurFunction();
@@ -352,6 +396,33 @@ public:
     return std::next(Stack.back().first.rbegin())->Directive;
   }
 
+  /// Add requires decl to internal vector
+  void addRequiresDecl(OMPRequiresDecl *RD) {
+    RequiresDecls.push_back(RD);
+  }
+
+  /// Checks for a duplicate clause amongst previously declared requires
+  /// directives
+  bool hasDuplicateRequiresClause(ArrayRef<OMPClause *> ClauseList) const {
+    bool IsDuplicate = false;
+    for (OMPClause *CNew : ClauseList) {
+      for (const OMPRequiresDecl *D : RequiresDecls) {
+        for (const OMPClause *CPrev : D->clauselists()) {
+          if (CNew->getClauseKind() == CPrev->getClauseKind()) {
+            SemaRef.Diag(CNew->getBeginLoc(),
+                         diag::err_omp_requires_clause_redeclaration)
+                << getOpenMPClauseName(CNew->getClauseKind());
+            SemaRef.Diag(CPrev->getBeginLoc(),
+                         diag::note_omp_requires_previous_clause)
+                << getOpenMPClauseName(CPrev->getClauseKind());
+            IsDuplicate = true;
+          }
+        }
+      }
+    }
+    return IsDuplicate;
+  }
+
   /// Set default data sharing attribute to none.
   void setDefaultDSANone(SourceLocation Loc) {
     assert(!isStackEmpty());
@@ -591,17 +662,34 @@ public:
     return llvm::make_range(StackElem.DoacrossDepends.end(),
                             StackElem.DoacrossDepends.end());
   }
+
+  // Store types of classes which have been explicitly mapped
+  void addMappedClassesQualTypes(QualType QT) {
+    SharingMapTy &StackElem = Stack.back().first.back();
+    StackElem.MappedClassesQualTypes.insert(QT);
+  }
+
+  // Return set of mapped classes types
+  bool isClassPreviouslyMapped(QualType QT) const {
+    const SharingMapTy &StackElem = Stack.back().first.back();
+    return StackElem.MappedClassesQualTypes.count(QT) != 0;
+  }
+
 };
-bool isParallelOrTaskRegion(OpenMPDirectiveKind DKind) {
-  return isOpenMPParallelDirective(DKind) || isOpenMPTaskingDirective(DKind) ||
-         isOpenMPTeamsDirective(DKind) || DKind == OMPD_unknown;
+
+bool isImplicitTaskingRegion(OpenMPDirectiveKind DKind) {
+  return isOpenMPParallelDirective(DKind) || isOpenMPTeamsDirective(DKind);
+}
+
+bool isImplicitOrExplicitTaskingRegion(OpenMPDirectiveKind DKind) {
+  return isImplicitTaskingRegion(DKind) || isOpenMPTaskingDirective(DKind) || DKind == OMPD_unknown;
 }
 
 } // namespace
 
 static const Expr *getExprAsWritten(const Expr *E) {
-  if (const auto *ExprTemp = dyn_cast<ExprWithCleanups>(E))
-    E = ExprTemp->getSubExpr();
+  if (const auto *FE = dyn_cast<FullExpr>(E))
+    E = FE->getSubExpr();
 
   if (const auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
     E = MTE->GetTemporaryExpr();
@@ -735,7 +823,7 @@ DSAStackTy::DSAVarData DSAStackTy::getDSA(iterator &Iter,
           DVar.CKind = OMPC_firstprivate;
           return DVar;
         }
-      } while (I != E && !isParallelOrTaskRegion(I->Directive));
+      } while (I != E && !isImplicitTaskingRegion(I->Directive));
       DVar.CKind =
           (DVarTemp.CKind == OMPC_unknown) ? OMPC_firstprivate : OMPC_shared;
       return DVar;
@@ -982,7 +1070,7 @@ bool DSAStackTy::isOpenMPLocal(VarDecl *D, iterator Iter) const {
   if (!isStackEmpty()) {
     iterator I = Iter, E = Stack.back().first.rend();
     Scope *TopScope = nullptr;
-    while (I != E && !isParallelOrTaskRegion(I->Directive) &&
+    while (I != E && !isImplicitOrExplicitTaskingRegion(I->Directive) &&
            !isOpenMPTargetExecutionDirective(I->Directive))
       ++I;
     if (I == E)
@@ -996,6 +1084,51 @@ bool DSAStackTy::isOpenMPLocal(VarDecl *D, iterator Iter) const {
   return false;
 }
 
+static bool isConstNotMutableType(Sema &SemaRef, QualType Type,
+                                  bool AcceptIfMutable = true,
+                                  bool *IsClassType = nullptr) {
+  ASTContext &Context = SemaRef.getASTContext();
+  Type = Type.getNonReferenceType().getCanonicalType();
+  bool IsConstant = Type.isConstant(Context);
+  Type = Context.getBaseElementType(Type);
+  const CXXRecordDecl *RD = AcceptIfMutable && SemaRef.getLangOpts().CPlusPlus
+                                ? Type->getAsCXXRecordDecl()
+                                : nullptr;
+  if (const auto *CTSD = dyn_cast_or_null<ClassTemplateSpecializationDecl>(RD))
+    if (const ClassTemplateDecl *CTD = CTSD->getSpecializedTemplate())
+      RD = CTD->getTemplatedDecl();
+  if (IsClassType)
+    *IsClassType = RD;
+  return IsConstant && !(SemaRef.getLangOpts().CPlusPlus && RD &&
+                         RD->hasDefinition() && RD->hasMutableFields());
+}
+
+static bool rejectConstNotMutableType(Sema &SemaRef, const ValueDecl *D,
+                                      QualType Type, OpenMPClauseKind CKind,
+                                      SourceLocation ELoc,
+                                      bool AcceptIfMutable = true,
+                                      bool ListItemNotVar = false) {
+  ASTContext &Context = SemaRef.getASTContext();
+  bool IsClassType;
+  if (isConstNotMutableType(SemaRef, Type, AcceptIfMutable, &IsClassType)) {
+    unsigned Diag = ListItemNotVar
+                        ? diag::err_omp_const_list_item
+                        : IsClassType ? diag::err_omp_const_not_mutable_variable
+                                      : diag::err_omp_const_variable;
+    SemaRef.Diag(ELoc, Diag) << getOpenMPClauseName(CKind);
+    if (!ListItemNotVar && D) {
+      const VarDecl *VD = dyn_cast<VarDecl>(D);
+      bool IsDecl = !VD || VD->isThisDeclarationADefinition(Context) ==
+                               VarDecl::DeclarationOnly;
+      SemaRef.Diag(D->getLocation(),
+                   IsDecl ? diag::note_previous_decl : diag::note_defined_here)
+          << D;
+    }
+    return true;
+  }
+  return false;
+}
+
 const DSAStackTy::DSAVarData DSAStackTy::getTopDSA(ValueDecl *D,
                                                    bool FromParent) {
   D = getCanonicalDecl(D);
@@ -1093,31 +1226,28 @@ const DSAStackTy::DSAVarData DSAStackTy::getTopDSA(ValueDecl *D,
     return DVar;
   }
 
-  QualType Type = D->getType().getNonReferenceType().getCanonicalType();
-  bool IsConstant = Type.isConstant(SemaRef.getASTContext());
-  Type = SemaRef.getASTContext().getBaseElementType(Type);
-  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
-  // in a Construct, C/C++, predetermined, p.6]
-  //  Variables with const qualified type having no mutable member are
-  //  shared.
-  const CXXRecordDecl *RD =
-      SemaRef.getLangOpts().CPlusPlus ? Type->getAsCXXRecordDecl() : nullptr;
-  if (const auto *CTSD = dyn_cast_or_null<ClassTemplateSpecializationDecl>(RD))
-    if (const ClassTemplateDecl *CTD = CTSD->getSpecializedTemplate())
-      RD = CTD->getTemplatedDecl();
-  if (IsConstant &&
-      !(SemaRef.getLangOpts().CPlusPlus && RD && RD->hasDefinition() &&
-        RD->hasMutableFields())) {
-    // Variables with const-qualified type having no mutable member may be
-    // listed in a firstprivate clause, even if they are static data members.
-    DSAVarData DVarTemp =
-        hasDSA(D, [](OpenMPClauseKind C) { return C == OMPC_firstprivate; },
-               MatchesAlways, FromParent);
-    if (DVarTemp.CKind == OMPC_firstprivate && DVarTemp.RefExpr)
-      return DVarTemp;
+  // The predetermined shared attribute for const-qualified types having no
+  // mutable members was removed after OpenMP 3.1.
+  if (SemaRef.LangOpts.OpenMP <= 31) {
+    // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
+    // in a Construct, C/C++, predetermined, p.6]
+    //  Variables with const qualified type having no mutable member are
+    //  shared.
+    if (isConstNotMutableType(SemaRef, D->getType())) {
+      // Variables with const-qualified type having no mutable member may be
+      // listed in a firstprivate clause, even if they are static data members.
+      DSAVarData DVarTemp = hasInnermostDSA(
+          D,
+          [](OpenMPClauseKind C) {
+            return C == OMPC_firstprivate || C == OMPC_shared;
+          },
+          MatchesAlways, FromParent);
+      if (DVarTemp.CKind != OMPC_unknown && DVarTemp.RefExpr)
+        return DVarTemp;
 
-    DVar.CKind = OMPC_shared;
-    return DVar;
+      DVar.CKind = OMPC_shared;
+      return DVar;
+    }
   }
 
   // Explicitly specified attributes and local variables with predetermined
@@ -1166,7 +1296,7 @@ DSAStackTy::hasDSA(ValueDecl *D,
   if (FromParent && I != EndI)
     std::advance(I, 1);
   for (; I != EndI; std::advance(I, 1)) {
-    if (!DPred(I->Directive) && !isParallelOrTaskRegion(I->Directive))
+    if (!DPred(I->Directive) && !isImplicitOrExplicitTaskingRegion(I->Directive))
       continue;
     iterator NewI = I;
     DSAVarData DVar = getDSA(NewI, D);
@@ -1206,10 +1336,16 @@ bool DSAStackTy::hasExplicitDSA(
     return false;
   std::advance(StartI, Level);
   auto I = StartI->SharingMap.find(D);
-  return (I != StartI->SharingMap.end()) &&
+  if ((I != StartI->SharingMap.end()) &&
          I->getSecond().RefExpr.getPointer() &&
          CPred(I->getSecond().Attributes) &&
-         (!NotLastprivate || !I->getSecond().RefExpr.getInt());
+         (!NotLastprivate || !I->getSecond().RefExpr.getInt()))
+    return true;
+  // Check predetermined rules for the loop control variables.
+  auto LI = StartI->LCVMap.find(D);
+  if (LI != StartI->LCVMap.end())
+    return CPred(OMPC_private);
+  return false;
 }
 
 bool DSAStackTy::hasExplicitDirective(
@@ -1376,6 +1512,8 @@ bool Sema::isOpenMPCapturedByRef(const ValueDecl *D, unsigned Level) const {
       // By default, all the data that has a scalar type is mapped by copy
       // (except for reduction variables).
       IsByRef =
+          (DSAStack->isForceCaptureByReferenceInTargetExecutable() &&
+           !Ty->isAnyPointerType()) ||
           !Ty->isScalarType() ||
           DSAStack->getDefaultDMAAtLevel(Level) == DMA_tofrom_scalar ||
           DSAStack->hasExplicitDSA(
@@ -1385,10 +1523,12 @@ bool Sema::isOpenMPCapturedByRef(const ValueDecl *D, unsigned Level) const {
 
   if (IsByRef && Ty.getNonReferenceType()->isScalarType()) {
     IsByRef =
-        !DSAStack->hasExplicitDSA(
-            D,
-            [](OpenMPClauseKind K) -> bool { return K == OMPC_firstprivate; },
-            Level, /*NotLastprivate=*/true) &&
+        ((DSAStack->isForceCaptureByReferenceInTargetExecutable() &&
+          !Ty->isAnyPointerType()) ||
+         !DSAStack->hasExplicitDSA(
+             D,
+             [](OpenMPClauseKind K) -> bool { return K == OMPC_firstprivate; },
+             Level, /*NotLastprivate=*/true)) &&
         // If the variable is artificial and must be captured by value - try to
         // capture by value.
         !(isa<OMPCapturedExprDecl>(D) && !D->hasAttr<OMPCaptureNoInitAttr>() &&
@@ -1425,7 +1565,7 @@ bool Sema::isInOpenMPTargetExecutionDirective() const {
              false);
 }
 
-VarDecl *Sema::isOpenMPCapturedDecl(ValueDecl *D) const {
+VarDecl *Sema::isOpenMPCapturedDecl(ValueDecl *D) {
   assert(LangOpts.OpenMP && "OpenMP is not allowed");
   D = getCanonicalDecl(D);
 
@@ -1433,13 +1573,65 @@ VarDecl *Sema::isOpenMPCapturedDecl(ValueDecl *D) const {
   // 'target' we return true so that this global is also mapped to the device.
   //
   auto *VD = dyn_cast<VarDecl>(D);
-  if (VD && !VD->hasLocalStorage() && isInOpenMPTargetExecutionDirective()) {
-    // If the declaration is enclosed in a 'declare target' directive,
-    // then it should not be captured.
-    //
-    if (OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD))
+  if (VD && !VD->hasLocalStorage()) {
+    if (isInOpenMPDeclareTargetContext() &&
+        (getCurCapturedRegion() || getCurBlock() || getCurLambda())) {
+      // Try to mark variable as declare target if it is used in capturing
+      // regions.
+      if (!OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD))
+        checkDeclIsAllowedInOpenMPTarget(nullptr, VD);
       return nullptr;
-    return VD;
+    } else if (isInOpenMPTargetExecutionDirective()) {
+      // If the declaration is enclosed in a 'declare target' directive,
+      // then it should not be captured.
+      //
+      if (OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD))
+        return nullptr;
+      return VD;
+    }
+  }
+  // Capture variables captured by reference in lambdas for target-based
+  // directives.
+  if (VD && !DSAStack->isClauseParsingMode()) {
+    if (const auto *RD = VD->getType()
+                             .getCanonicalType()
+                             .getNonReferenceType()
+                             ->getAsCXXRecordDecl()) {
+      bool SavedForceCaptureByReferenceInTargetExecutable =
+          DSAStack->isForceCaptureByReferenceInTargetExecutable();
+      DSAStack->setForceCaptureByReferenceInTargetExecutable(/*V=*/true);
+      if (RD->isLambda()) {
+        llvm::DenseMap<const VarDecl *, FieldDecl *> Captures;
+        FieldDecl *ThisCapture;
+        RD->getCaptureFields(Captures, ThisCapture);
+        for (const LambdaCapture &LC : RD->captures()) {
+          if (LC.getCaptureKind() == LCK_ByRef) {
+            VarDecl *VD = LC.getCapturedVar();
+            DeclContext *VDC = VD->getDeclContext();
+            if (!VDC->Encloses(CurContext))
+              continue;
+            DSAStackTy::DSAVarData DVarPrivate =
+                DSAStack->getTopDSA(VD, /*FromParent=*/false);
+            // Do not capture already captured variables.
+            if (!OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD) &&
+                DVarPrivate.CKind == OMPC_unknown &&
+                !DSAStack->checkMappableExprComponentListsForDecl(
+                    D, /*CurrentRegionOnly=*/true,
+                    [](OMPClauseMappableExprCommon::
+                           MappableExprComponentListRef,
+                       OpenMPClauseKind) { return true; }))
+              MarkVariableReferenced(LC.getLocation(), LC.getCapturedVar());
+          } else if (LC.getCaptureKind() == LCK_This) {
+            QualType ThisTy = getCurrentThisType();
+            if (!ThisTy.isNull() &&
+                Context.typesAreCompatible(ThisTy, ThisCapture->getType()))
+              CheckCXXThisCapture(LC.getLocation());
+          }
+        }
+      }
+      DSAStack->setForceCaptureByReferenceInTargetExecutable(
+          SavedForceCaptureByReferenceInTargetExecutable);
+    }
   }
 
   if (DSAStack->getCurrentDirective() != OMPD_unknown &&
@@ -1448,7 +1640,7 @@ VarDecl *Sema::isOpenMPCapturedDecl(ValueDecl *D) const {
     auto &&Info = DSAStack->isLoopControlVariable(D);
     if (Info.first ||
         (VD && VD->hasLocalStorage() &&
-         isParallelOrTaskRegion(DSAStack->getCurrentDirective())) ||
+         isImplicitOrExplicitTaskingRegion(DSAStack->getCurrentDirective())) ||
         (VD && DSAStack->isForceVarCapturing()))
       return VD ? VD : Info.second;
     DSAStackTy::DSAVarData DVarPrivate =
@@ -1471,8 +1663,28 @@ void Sema::adjustOpenMPTargetScopeIndex(unsigned &FunctionScopesIndex,
   FunctionScopesIndex -= Regions.size();
 }
 
+void Sema::startOpenMPLoop() {
+  assert(LangOpts.OpenMP && "OpenMP must be enabled.");
+  if (isOpenMPLoopDirective(DSAStack->getCurrentDirective()))
+    DSAStack->loopInit();
+}
+
 bool Sema::isOpenMPPrivateDecl(const ValueDecl *D, unsigned Level) const {
   assert(LangOpts.OpenMP && "OpenMP is not allowed");
+  if (isOpenMPLoopDirective(DSAStack->getCurrentDirective())) {
+    if (DSAStack->getAssociatedLoops() > 0 &&
+        !DSAStack->isLoopStarted()) {
+      DSAStack->resetPossibleLoopCounter(D);
+      DSAStack->loopStart();
+      return true;
+    }
+    if ((DSAStack->getPossiblyLoopCunter() == D->getCanonicalDecl() ||
+         DSAStack->isLoopControlVariable(D).first) &&
+        !DSAStack->hasExplicitDSA(
+            D, [](OpenMPClauseKind K) { return K != OMPC_private; }, Level) &&
+        !isOpenMPSimdDirective(DSAStack->getCurrentDirective()))
+      return true;
+  }
   return DSAStack->hasExplicitDSA(
              D, [](OpenMPClauseKind K) { return K == OMPC_private; }, Level) ||
          (DSAStack->isClauseParsingMode() &&
@@ -1788,7 +2000,7 @@ public:
   bool VisitDeclRefExpr(const DeclRefExpr *E) {
     if (const auto *VD = dyn_cast<VarDecl>(E->getDecl())) {
       if (VD->hasLocalStorage()) {
-        SemaRef.Diag(E->getLocStart(),
+        SemaRef.Diag(E->getBeginLoc(),
                      diag::err_omp_local_var_in_threadprivate_init)
             << E->getSourceRange();
         SemaRef.Diag(VD->getLocation(), diag::note_defined_here)
@@ -1890,6 +2102,30 @@ Sema::CheckOMPThreadPrivateDecl(SourceLocation Loc, ArrayRef<Expr *> VarList) {
   return D;
 }
 
+Sema::DeclGroupPtrTy
+Sema::ActOnOpenMPRequiresDirective(SourceLocation Loc,
+                                   ArrayRef<OMPClause *> ClauseList) {
+  OMPRequiresDecl *D = nullptr;
+  if (!CurContext->isFileContext()) {
+    Diag(Loc, diag::err_omp_invalid_scope) << "requires";
+  } else {
+    D = CheckOMPRequiresDecl(Loc, ClauseList);
+    if (D) {
+      CurContext->addDecl(D);
+      DSAStack->addRequiresDecl(D);
+    }
+  }
+  return DeclGroupPtrTy::make(DeclGroupRef(D));
+}
+
+OMPRequiresDecl *Sema::CheckOMPRequiresDecl(SourceLocation Loc,
+                                            ArrayRef<OMPClause *> ClauseList) {
+  if (!DSAStack->hasDuplicateRequiresClause(ClauseList))
+    return OMPRequiresDecl::Create(Context, getCurLexicalContext(), Loc,
+                                   ClauseList);
+  return nullptr;
+}
+
 static void reportOriginalDsa(Sema &SemaRef, const DSAStackTy *Stack,
                               const ValueDecl *D,
                               const DSAStackTy::DSAVarData &DVar,
@@ -1958,6 +2194,30 @@ class DSAAttrChecker final : public StmtVisitor<DSAAttrChecker, void> {
   Sema::VarsWithInheritedDSAType VarsWithInheritedDSA;
   llvm::SmallDenseSet<const ValueDecl *, 4> ImplicitDeclarations;
 
+  void VisitSubCaptures(OMPExecutableDirective *S) {
+    // Check implicitly captured variables.
+    if (!S->hasAssociatedStmt() || !S->getAssociatedStmt())
+      return;
+    for (const CapturedStmt::Capture &Cap :
+         S->getInnermostCapturedStmt()->captures()) {
+      if (!Cap.capturesVariable())
+        continue;
+      VarDecl *VD = Cap.getCapturedVar();
+      // Do not try to map the variable if it or its sub-component was mapped
+      // already.
+      if (isOpenMPTargetExecutionDirective(Stack->getCurrentDirective()) &&
+          Stack->checkMappableExprComponentListsForDecl(
+              VD, /*CurrentRegionOnly=*/true,
+              [](OMPClauseMappableExprCommon::MappableExprComponentListRef,
+                 OpenMPClauseKind) { return true; }))
+        continue;
+      DeclRefExpr *DRE = buildDeclRefExpr(
+          SemaRef, VD, VD->getType().getNonLValueExprType(SemaRef.Context),
+          Cap.getLocation(), /*RefersToCapture=*/true);
+      Visit(DRE);
+    }
+  }
+
 public:
   void VisitDeclRefExpr(DeclRefExpr *E) {
     if (E->isTypeDependent() || E->isValueDependent() ||
@@ -1988,7 +2248,7 @@ public:
       // attribute, must have its data-sharing attribute explicitly determined
       // by being listed in a data-sharing attribute clause.
       if (DVar.CKind == OMPC_unknown && Stack->getDefaultDSA() == DSA_none &&
-          isParallelOrTaskRegion(DKind) &&
+          isImplicitOrExplicitTaskingRegion(DKind) &&
           VarsWithInheritedDSA.count(VD) == 0) {
         VarsWithInheritedDSA[VD] = E;
         return;
@@ -2065,7 +2325,7 @@ public:
       return;
     auto *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
     OpenMPDirectiveKind DKind = Stack->getCurrentDirective();
-    if (isa<CXXThisExpr>(E->getBase()->IgnoreParens())) {
+    if (auto *TE = dyn_cast<CXXThisExpr>(E->getBase()->IgnoreParens())) {
       if (!FD)
         return;
       DSAStackTy::DSAVarData DVar = Stack->getTopDSA(FD, /*FromParent=*/false);
@@ -2092,6 +2352,12 @@ public:
         //
         if (FD->isBitField())
           return;
+
+        // Check to see if the member expression is referencing a class that
+        // has already been explicitly mapped
+        if (Stack->isClassPreviouslyMapped(TE->getType()))
+          return;
+
         ImplicitMap.emplace_back(E);
         return;
       }
@@ -2118,8 +2384,14 @@ public:
       // Define implicit data-sharing attributes for task.
       DVar = Stack->getImplicitDSA(FD, /*FromParent=*/false);
       if (isOpenMPTaskingDirective(DKind) && DVar.CKind != OMPC_shared &&
-          !Stack->isLoopControlVariable(FD).first)
-        ImplicitFirstprivate.push_back(E);
+          !Stack->isLoopControlVariable(FD).first) {
+        // Check if there is a captured expression for the current field in the
+        // region. Do not mark it as firstprivate unless there is no captured
+        // expression.
+        // TODO: try to make it firstprivate.
+        if (DVar.CKind != OMPC_unknown)
+          ImplicitFirstprivate.push_back(E);
+      }
       return;
     }
     if (isOpenMPTargetExecutionDirective(DKind)) {
@@ -2179,11 +2451,16 @@ public:
         }
       }
     }
+    // Check implicitly captured variables.
+    VisitSubCaptures(S);
   }
   void VisitStmt(Stmt *S) {
     for (Stmt *C : S->children()) {
-      if (C && !isa<OMPExecutableDirective>(C))
+      if (C) {
+        // Check implicitly captured variables in the task-based directives to
+        // check if they must be firstprivatized.
         Visit(C);
+      }
     }
   }
 
@@ -2535,6 +2812,7 @@ void Sema::ActOnOpenMPRegionStart(OpenMPDirectiveKind DKind, Scope *CurScope) {
   case OMPD_declare_simd:
   case OMPD_declare_target:
   case OMPD_end_declare_target:
+  case OMPD_requires:
     llvm_unreachable("OpenMP Directive is not allowed");
   case OMPD_unknown:
     llvm_unreachable("Unknown OpenMP directive");
@@ -2568,7 +2846,7 @@ static OMPCapturedExprDecl *buildCaptureDecl(Sema &S, IdentifierInfo *Id,
     WithInit = true;
   }
   auto *CED = OMPCapturedExprDecl::Create(C, S.CurContext, Id, Ty,
-                                          CaptureExpr->getLocStart());
+                                          CaptureExpr->getBeginLoc());
   if (!WithInit)
     CED->addAttr(OMPCaptureNoInitAttr::CreateImplicit(C));
   S.CurContext->addHiddenDecl(CED);
@@ -2705,20 +2983,20 @@ StmtResult Sema::ActOnOpenMPRegionEnd(StmtResult S,
              ? SC->getFirstScheduleModifierLoc()
              : SC->getSecondScheduleModifierLoc(),
          diag::err_omp_schedule_nonmonotonic_ordered)
-        << SourceRange(OC->getLocStart(), OC->getLocEnd());
+        << SourceRange(OC->getBeginLoc(), OC->getEndLoc());
     ErrorFound = true;
   }
   if (!LCs.empty() && OC && OC->getNumForLoops()) {
     for (const OMPLinearClause *C : LCs) {
-      Diag(C->getLocStart(), diag::err_omp_linear_ordered)
-          << SourceRange(OC->getLocStart(), OC->getLocEnd());
+      Diag(C->getBeginLoc(), diag::err_omp_linear_ordered)
+          << SourceRange(OC->getBeginLoc(), OC->getEndLoc());
     }
     ErrorFound = true;
   }
   if (isOpenMPWorksharingDirective(DSAStack->getCurrentDirective()) &&
       isOpenMPSimdDirective(DSAStack->getCurrentDirective()) && OC &&
       OC->getNumForLoops()) {
-    Diag(OC->getLocStart(), diag::err_omp_ordered_simd)
+    Diag(OC->getBeginLoc(), diag::err_omp_ordered_simd)
         << getOpenMPDirectiveName(DSAStack->getCurrentDirective());
     ErrorFound = true;
   }
@@ -2820,11 +3098,13 @@ static bool checkNestingOfRegions(Sema &SemaRef, const DSAStackTy *Stack,
       }
       return false;
     }
-    // Allow some constructs (except teams) to be orphaned (they could be
-    // used in functions, called from OpenMP regions with the required
-    // preconditions).
+    // Allow some constructs (except teams and cancellation constructs) to be
+    // orphaned (they could be used in functions, called from OpenMP regions
+    // with the required preconditions).
     if (ParentRegion == OMPD_unknown &&
-        !isOpenMPNestingTeamsDirective(CurrentRegion))
+        !isOpenMPNestingTeamsDirective(CurrentRegion) &&
+        CurrentRegion != OMPD_cancellation_point &&
+        CurrentRegion != OMPD_cancel)
       return false;
     if (CurrentRegion == OMPD_cancellation_point ||
         CurrentRegion == OMPD_cancel) {
@@ -2853,6 +3133,7 @@ static bool checkNestingOfRegions(Sema &SemaRef, const DSAStackTy *Stack,
             (CancelRegion == OMPD_sections &&
              (ParentRegion == OMPD_section || ParentRegion == OMPD_sections ||
               ParentRegion == OMPD_parallel_sections)));
+      OrphanSeen = ParentRegion == OMPD_unknown;
     } else if (CurrentRegion == OMPD_master) {
       // OpenMP [2.16, Nesting of Regions]
       // A master region may not be closely nested inside a worksharing,
@@ -2997,7 +3278,7 @@ static bool checkIfClauses(Sema &S, OpenMPDirectiveKind Kind,
       // the directive.
       OpenMPDirectiveKind CurNM = IC->getNameModifier();
       if (FoundNameModifiers[CurNM]) {
-        S.Diag(C->getLocStart(), diag::err_omp_more_one_clause)
+        S.Diag(C->getBeginLoc(), diag::err_omp_more_one_clause)
             << getOpenMPDirectiveName(Kind) << getOpenMPClauseName(OMPC_if)
             << (CurNM != OMPD_unknown) << getOpenMPDirectiveName(CurNM);
         ErrorFound = true;
@@ -3031,7 +3312,7 @@ static bool checkIfClauses(Sema &S, OpenMPDirectiveKind Kind,
   // all if clauses on the directive must include a directive-name-modifier.
   if (FoundNameModifiers[OMPD_unknown] && NamedModifiersNumber > 0) {
     if (NamedModifiersNumber == AllowedNameModifiers.size()) {
-      S.Diag(FoundNameModifiers[OMPD_unknown]->getLocStart(),
+      S.Diag(FoundNameModifiers[OMPD_unknown]->getBeginLoc(),
              diag::err_omp_no_more_if_clause);
     } else {
       std::string Values;
@@ -3053,7 +3334,7 @@ static bool checkIfClauses(Sema &S, OpenMPDirectiveKind Kind,
           ++AllowedCnt;
         }
       }
-      S.Diag(FoundNameModifiers[OMPD_unknown]->getCondition()->getLocStart(),
+      S.Diag(FoundNameModifiers[OMPD_unknown]->getCondition()->getBeginLoc(),
              diag::err_omp_unnamed_if_clause)
           << (TotalAllowedNum > 1) << Values;
     }
@@ -3121,9 +3402,10 @@ StmtResult Sema::ActOnOpenMPExecutableDirective(
     }
     if (!ImplicitMaps.empty()) {
       if (OMPClause *Implicit = ActOnOpenMPMapClause(
-              OMPC_MAP_unknown, OMPC_MAP_tofrom, /*IsMapTypeImplicit=*/true,
-              SourceLocation(), SourceLocation(), ImplicitMaps,
-              SourceLocation(), SourceLocation(), SourceLocation())) {
+              llvm::None, llvm::None, OMPC_MAP_tofrom,
+              /*IsMapTypeImplicit=*/true, SourceLocation(), SourceLocation(),
+              ImplicitMaps, SourceLocation(), SourceLocation(),
+              SourceLocation())) {
         ClausesWithImplicit.emplace_back(Implicit);
         ErrorFound |=
             cast<OMPMapClause>(Implicit)->varlist_size() != ImplicitMaps.size();
@@ -3376,6 +3658,7 @@ StmtResult Sema::ActOnOpenMPExecutableDirective(
   case OMPD_threadprivate:
   case OMPD_declare_reduction:
   case OMPD_declare_simd:
+  case OMPD_requires:
     llvm_unreachable("OpenMP Directive is not allowed");
   case OMPD_unknown:
     llvm_unreachable("Unknown OpenMP directive");
@@ -3695,7 +3978,8 @@ class OpenMPIterationSpaceChecker {
   ///   Var <= UB
   ///   UB  >  Var
   ///   UB  >= Var
-  bool TestIsLessOp = false;
+  /// This will have no value when the condition is !=
+  llvm::Optional<bool> TestIsLessOp;
   /// This flag is true when condition is strict ( < or > ).
   bool TestIsStrictOp = false;
   /// This flag is true when step is subtracted on each iteration.
@@ -3761,8 +4045,8 @@ private:
   /// Helper to set loop counter variable and its initializer.
   bool setLCDeclAndLB(ValueDecl *NewLCDecl, Expr *NewDeclRefExpr, Expr *NewLB);
   /// Helper to set upper bound.
-  bool setUB(Expr *NewUB, bool LessOp, bool StrictOp, SourceRange SR,
-             SourceLocation SL);
+  bool setUB(Expr *NewUB, llvm::Optional<bool> LessOp, bool StrictOp,
+             SourceRange SR, SourceLocation SL);
   /// Helper to set loop increment.
   bool setStep(Expr *NewStep, bool Subtract);
 };
@@ -3797,15 +4081,17 @@ bool OpenMPIterationSpaceChecker::setLCDeclAndLB(ValueDecl *NewLCDecl,
   return false;
 }
 
-bool OpenMPIterationSpaceChecker::setUB(Expr *NewUB, bool LessOp, bool StrictOp,
-                                        SourceRange SR, SourceLocation SL) {
+bool OpenMPIterationSpaceChecker::setUB(Expr *NewUB, llvm::Optional<bool> LessOp,
+                                        bool StrictOp, SourceRange SR,
+                                        SourceLocation SL) {
   // State consistency checking to ensure correct usage.
   assert(LCDecl != nullptr && LB != nullptr && UB == nullptr &&
          Step == nullptr && !TestIsLessOp && !TestIsStrictOp);
   if (!NewUB)
     return true;
   UB = NewUB;
-  TestIsLessOp = LessOp;
+  if (LessOp)
+    TestIsLessOp = LessOp;
   TestIsStrictOp = StrictOp;
   ConditionSrcRange = SR;
   ConditionLoc = SL;
@@ -3819,7 +4105,7 @@ bool OpenMPIterationSpaceChecker::setStep(Expr *NewStep, bool Subtract) {
     return true;
   if (!NewStep->isValueDependent()) {
     // Check that the step is integer expression.
-    SourceLocation StepLoc = NewStep->getLocStart();
+    SourceLocation StepLoc = NewStep->getBeginLoc();
     ExprResult Val = SemaRef.PerformOpenMPImplicitIntegerConversion(
         StepLoc, getExprAsWritten(NewStep));
     if (Val.isInvalid())
@@ -3845,18 +4131,23 @@ bool OpenMPIterationSpaceChecker::setStep(Expr *NewStep, bool Subtract) {
     bool IsConstPos =
         IsConstant && Result.isSigned() && (Subtract == Result.isNegative());
     bool IsConstZero = IsConstant && !Result.getBoolValue();
+
+    // != with increment is treated as <; != with decrement is treated as >
+    if (!TestIsLessOp.hasValue())
+      TestIsLessOp = IsConstPos || (IsUnsigned && !Subtract);
     if (UB && (IsConstZero ||
-               (TestIsLessOp ? (IsConstNeg || (IsUnsigned && Subtract))
-                             : (IsConstPos || (IsUnsigned && !Subtract))))) {
+               (TestIsLessOp.getValue() ?
+                  (IsConstNeg || (IsUnsigned && Subtract)) :
+                  (IsConstPos || (IsUnsigned && !Subtract))))) {
       SemaRef.Diag(NewStep->getExprLoc(),
                    diag::err_omp_loop_incr_not_compatible)
-          << LCDecl << TestIsLessOp << NewStep->getSourceRange();
+          << LCDecl << TestIsLessOp.getValue() << NewStep->getSourceRange();
       SemaRef.Diag(ConditionLoc,
                    diag::note_omp_loop_cond_requres_compatible_incr)
-          << TestIsLessOp << ConditionSrcRange;
+          << TestIsLessOp.getValue() << ConditionSrcRange;
       return true;
     }
-    if (TestIsLessOp == Subtract) {
+    if (TestIsLessOp.getValue() == Subtract) {
       NewStep =
           SemaRef.CreateBuiltinUnaryOp(NewStep->getExprLoc(), UO_Minus, NewStep)
               .get();
@@ -3912,14 +4203,14 @@ bool OpenMPIterationSpaceChecker::checkAndSetInit(Stmt *S, bool EmitDiags) {
         if (Var->hasInit() && !Var->getType()->isReferenceType()) {
           // Accept non-canonical init form here but emit ext. warning.
           if (Var->getInitStyle() != VarDecl::CInit && EmitDiags)
-            SemaRef.Diag(S->getLocStart(),
+            SemaRef.Diag(S->getBeginLoc(),
                          diag::ext_omp_loop_not_canonical_init)
                 << S->getSourceRange();
           return setLCDeclAndLB(
               Var,
               buildDeclRefExpr(SemaRef, Var,
                                Var->getType().getNonReferenceType(),
-                               DS->getLocStart()),
+                               DS->getBeginLoc()),
               Var->getInit());
         }
       }
@@ -3944,7 +4235,7 @@ bool OpenMPIterationSpaceChecker::checkAndSetInit(Stmt *S, bool EmitDiags) {
   if (dependent() || SemaRef.CurContext->isDependentContext())
     return false;
   if (EmitDiags) {
-    SemaRef.Diag(S->getLocStart(), diag::err_omp_loop_not_canonical_init)
+    SemaRef.Diag(S->getBeginLoc(), diag::err_omp_loop_not_canonical_init)
         << S->getSourceRange();
   }
   return true;
@@ -3984,7 +4275,7 @@ bool OpenMPIterationSpaceChecker::checkAndSetCond(Expr *S) {
     return true;
   }
   S = getExprAsWritten(S);
-  SourceLocation CondLoc = S->getLocStart();
+  SourceLocation CondLoc = S->getBeginLoc();
   if (auto *BO = dyn_cast<BinaryOperator>(S)) {
     if (BO->isRelationalOp()) {
       if (getInitLCDecl(BO->getLHS()) == LCDecl)
@@ -3997,7 +4288,12 @@ bool OpenMPIterationSpaceChecker::checkAndSetCond(Expr *S) {
                      (BO->getOpcode() == BO_GT || BO->getOpcode() == BO_GE),
                      (BO->getOpcode() == BO_LT || BO->getOpcode() == BO_GT),
                      BO->getSourceRange(), BO->getOperatorLoc());
-    }
+    } else if (BO->getOpcode() == BO_NE)
+        return setUB(getInitLCDecl(BO->getLHS()) == LCDecl ?
+                       BO->getRHS() : BO->getLHS(),
+                     /*LessOp=*/llvm::None,
+                     /*StrictOp=*/true,
+                     BO->getSourceRange(), BO->getOperatorLoc());
   } else if (auto *CE = dyn_cast<CXXOperatorCallExpr>(S)) {
     if (CE->getNumArgs() == 2) {
       auto Op = CE->getOperator();
@@ -4015,6 +4311,14 @@ bool OpenMPIterationSpaceChecker::checkAndSetCond(Expr *S) {
                        Op == OO_Less || Op == OO_Greater, CE->getSourceRange(),
                        CE->getOperatorLoc());
         break;
+      case OO_ExclaimEqual:
+        return setUB(getInitLCDecl(CE->getArg(0)) == LCDecl ?
+                     CE->getArg(1) : CE->getArg(0),
+                     /*LessOp=*/llvm::None,
+                     /*StrictOp=*/true,
+                     CE->getSourceRange(),
+                     CE->getOperatorLoc());
+        break;
       default:
         break;
       }
@@ -4053,7 +4357,7 @@ bool OpenMPIterationSpaceChecker::checkAndSetIncRHS(Expr *RHS) {
   }
   if (dependent() || SemaRef.CurContext->isDependentContext())
     return false;
-  SemaRef.Diag(RHS->getLocStart(), diag::err_omp_loop_not_canonical_incr)
+  SemaRef.Diag(RHS->getBeginLoc(), diag::err_omp_loop_not_canonical_incr)
       << RHS->getSourceRange() << LCDecl;
   return true;
 }
@@ -4086,7 +4390,7 @@ bool OpenMPIterationSpaceChecker::checkAndSetInc(Expr *S) {
     if (UO->isIncrementDecrementOp() &&
         getInitLCDecl(UO->getSubExpr()) == LCDecl)
       return setStep(SemaRef
-                         .ActOnIntegerConstant(UO->getLocStart(),
+                         .ActOnIntegerConstant(UO->getBeginLoc(),
                                                (UO->isDecrementOp() ? -1 : 1))
                          .get(),
                      /*Subtract=*/false);
@@ -4111,7 +4415,7 @@ bool OpenMPIterationSpaceChecker::checkAndSetInc(Expr *S) {
       if (getInitLCDecl(CE->getArg(0)) == LCDecl)
         return setStep(SemaRef
                            .ActOnIntegerConstant(
-                               CE->getLocStart(),
+                               CE->getBeginLoc(),
                                ((CE->getOperator() == OO_MinusMinus) ? -1 : 1))
                            .get(),
                        /*Subtract=*/false);
@@ -4131,7 +4435,7 @@ bool OpenMPIterationSpaceChecker::checkAndSetInc(Expr *S) {
   }
   if (dependent() || SemaRef.CurContext->isDependentContext())
     return false;
-  SemaRef.Diag(S->getLocStart(), diag::err_omp_loop_not_canonical_incr)
+  SemaRef.Diag(S->getBeginLoc(), diag::err_omp_loop_not_canonical_incr)
       << S->getSourceRange() << LCDecl;
   return true;
 }
@@ -4163,8 +4467,8 @@ Expr *OpenMPIterationSpaceChecker::buildNumIterations(
   if (VarType->isIntegerType() || VarType->isPointerType() ||
       SemaRef.getLangOpts().CPlusPlus) {
     // Upper - Lower
-    Expr *UBExpr = TestIsLessOp ? UB : LB;
-    Expr *LBExpr = TestIsLessOp ? LB : UB;
+    Expr *UBExpr = TestIsLessOp.getValue() ? UB : LB;
+    Expr *LBExpr = TestIsLessOp.getValue() ? LB : UB;
     Expr *Upper = tryBuildCapture(SemaRef, UBExpr, Captures).get();
     Expr *Lower = tryBuildCapture(SemaRef, LBExpr, Captures).get();
     if (!Upper || !Lower)
@@ -4175,7 +4479,7 @@ Expr *OpenMPIterationSpaceChecker::buildNumIterations(
     if (!Diff.isUsable() && VarType->getAsCXXRecordDecl()) {
       // BuildBinOp already emitted error, this one is to point user to upper
       // and lower bound, and to tell what is passed to 'operator-'.
-      SemaRef.Diag(Upper->getLocStart(), diag::err_omp_loop_diff_cxx)
+      SemaRef.Diag(Upper->getBeginLoc(), diag::err_omp_loop_diff_cxx)
           << Upper->getSourceRange() << Lower->getSourceRange();
       return nullptr;
     }
@@ -4265,8 +4569,9 @@ Expr *OpenMPIterationSpaceChecker::buildPreCond(
 
   ExprResult CondExpr =
       SemaRef.BuildBinOp(S, DefaultLoc,
-                         TestIsLessOp ? (TestIsStrictOp ? BO_LT : BO_LE)
-                                      : (TestIsStrictOp ? BO_GT : BO_GE),
+                         TestIsLessOp.getValue() ?
+                           (TestIsStrictOp ? BO_LT : BO_LE) :
+                           (TestIsStrictOp ? BO_GT : BO_GE),
                          NewLB.get(), NewUB.get());
   if (CondExpr.isUsable()) {
     if (!SemaRef.Context.hasSameUnqualifiedType(CondExpr.get()->getType(),
@@ -4344,9 +4649,9 @@ Expr *OpenMPIterationSpaceChecker::buildOrderedLoopData(
       SemaRef.getLangOpts().CPlusPlus) {
     // Upper - Lower
     Expr *Upper =
-        TestIsLessOp ? Cnt : tryBuildCapture(SemaRef, UB, Captures).get();
+        TestIsLessOp.getValue() ? Cnt : tryBuildCapture(SemaRef, UB, Captures).get();
     Expr *Lower =
-        TestIsLessOp ? tryBuildCapture(SemaRef, LB, Captures).get() : Cnt;
+        TestIsLessOp.getValue() ? tryBuildCapture(SemaRef, LB, Captures).get() : Cnt;
     if (!Upper || !Lower)
       return nullptr;
 
@@ -4355,7 +4660,7 @@ Expr *OpenMPIterationSpaceChecker::buildOrderedLoopData(
     if (!Diff.isUsable() && VarType->getAsCXXRecordDecl()) {
       // BuildBinOp already emitted error, this one is to point user to upper
       // and lower bound, and to tell what is passed to 'operator-'.
-      SemaRef.Diag(Upper->getLocStart(), diag::err_omp_loop_diff_cxx)
+      SemaRef.Diag(Upper->getBeginLoc(), diag::err_omp_loop_diff_cxx)
           << Upper->getSourceRange() << Lower->getSourceRange();
       return nullptr;
     }
@@ -4414,6 +4719,7 @@ void Sema::ActOnOpenMPLoopInitialization(SourceLocation ForLoc, Stmt *Init) {
   unsigned AssociatedLoops = DSAStack->getAssociatedLoops();
   if (AssociatedLoops > 0 &&
       isOpenMPLoopDirective(DSAStack->getCurrentDirective())) {
+    DSAStack->loopStart();
     OpenMPIterationSpaceChecker ISC(*this, ForLoc);
     if (!ISC.checkAndSetInit(Init, /*EmitDiags=*/false)) {
       if (ValueDecl *D = ISC.getLoopDecl()) {
@@ -4428,6 +4734,15 @@ void Sema::ActOnOpenMPLoopInitialization(SourceLocation ForLoc, Stmt *Init) {
           }
         }
         DSAStack->addLoopControlVariable(D, VD);
+        const Decl *LD = DSAStack->getPossiblyLoopCunter();
+        if (LD != D->getCanonicalDecl()) {
+          DSAStack->resetPossibleLoopCounter();
+          if (auto *Var = dyn_cast_or_null<VarDecl>(LD))
+            MarkDeclarationsReferencedInExpr(
+                buildDeclRefExpr(*this, const_cast<VarDecl *>(Var),
+                                 Var->getType().getNonLValueExprType(Context),
+                                 ForLoc, /*RefersToCapture=*/true));
+        }
       }
     }
     DSAStack->setAssociatedLoops(AssociatedLoops - 1);
@@ -4448,7 +4763,7 @@ static bool checkOpenMPIterationSpace(
   //   for (init-expr; test-expr; incr-expr) structured-block
   auto *For = dyn_cast_or_null<ForStmt>(S);
   if (!For) {
-    SemaRef.Diag(S->getLocStart(), diag::err_omp_not_for)
+    SemaRef.Diag(S->getBeginLoc(), diag::err_omp_not_for)
         << (CollapseLoopCountExpr != nullptr || OrderedLoopCountExpr != nullptr)
         << getOpenMPDirectiveName(DKind) << TotalNestedLoopCount
         << (CurrentNestedLoopCount > 0) << CurrentNestedLoopCount;
@@ -4493,7 +4808,7 @@ static bool checkOpenMPIterationSpace(
     if (!VarType->isDependentType() && !VarType->isIntegerType() &&
         !VarType->isPointerType() &&
         !(SemaRef.getLangOpts().CPlusPlus && VarType->isOverloadableType())) {
-      SemaRef.Diag(Init->getLocStart(), diag::err_omp_loop_variable_type)
+      SemaRef.Diag(Init->getBeginLoc(), diag::err_omp_loop_variable_type)
           << SemaRef.getLangOpts().CPlusPlus;
       HasErrors = true;
     }
@@ -4531,7 +4846,7 @@ static bool checkOpenMPIterationSpace(
           !isOpenMPSimdDirective(DKind) && DVar.CKind != OMPC_unknown &&
           DVar.CKind != OMPC_private && DVar.CKind != OMPC_lastprivate)) &&
         (DVar.CKind != OMPC_private || DVar.RefExpr != nullptr)) {
-      SemaRef.Diag(Init->getLocStart(), diag::err_omp_loop_var_dsa)
+      SemaRef.Diag(Init->getBeginLoc(), diag::err_omp_loop_var_dsa)
           << getOpenMPClauseName(DVar.CKind) << getOpenMPDirectiveName(DKind)
           << getOpenMPClauseName(PredeterminedCKind);
       if (DVar.RefExpr == nullptr)
@@ -4801,15 +5116,16 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
   unsigned NestedLoopCount = 1;
   if (CollapseLoopCountExpr) {
     // Found 'collapse' clause - calculate collapse number.
-    llvm::APSInt Result;
+    Expr::EvalResult Result;
     if (CollapseLoopCountExpr->EvaluateAsInt(Result, SemaRef.getASTContext()))
-      NestedLoopCount = Result.getLimitedValue();
+      NestedLoopCount = Result.Val.getInt().getLimitedValue();
   }
   unsigned OrderedLoopCount = 1;
   if (OrderedLoopCountExpr) {
     // Found 'ordered' clause - calculate collapse number.
-    llvm::APSInt Result;
-    if (OrderedLoopCountExpr->EvaluateAsInt(Result, SemaRef.getASTContext())) {
+    Expr::EvalResult EVResult;
+    if (OrderedLoopCountExpr->EvaluateAsInt(EVResult, SemaRef.getASTContext())) {
+      llvm::APSInt Result = EVResult.Val.getInt();
       if (Result.getLimitedValue() < NestedLoopCount) {
         SemaRef.Diag(OrderedLoopCountExpr->getExprLoc(),
                      diag::err_omp_wrong_ordered_loop_count)
@@ -4954,13 +5270,14 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
 
   // Choose either the 32-bit or 64-bit version.
   ExprResult LastIteration = LastIteration64;
-  if (LastIteration32.isUsable() &&
-      C.getTypeSize(LastIteration32.get()->getType()) == 32 &&
-      (AllCountsNeedLessThan32Bits || NestedLoopCount == 1 ||
-       fitsInto(
-           /*Bits=*/32,
-           LastIteration32.get()->getType()->hasSignedIntegerRepresentation(),
-           LastIteration64.get(), SemaRef)))
+  if (SemaRef.getLangOpts().OpenMPOptimisticCollapse ||
+      (LastIteration32.isUsable() &&
+       C.getTypeSize(LastIteration32.get()->getType()) == 32 &&
+       (AllCountsNeedLessThan32Bits || NestedLoopCount == 1 ||
+        fitsInto(
+            /*Bits=*/32,
+            LastIteration32.get()->getType()->hasSignedIntegerRepresentation(),
+            LastIteration64.get(), SemaRef))))
     LastIteration = LastIteration32;
   QualType VType = LastIteration.get()->getType();
   QualType RealVType = VType;
@@ -5050,7 +5367,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
         LastIteration.get(), UB.get());
     EUB = SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, UB.get(),
                              CondOp.get());
-    EUB = SemaRef.ActOnFinishFullExpr(EUB.get());
+    EUB = SemaRef.ActOnFinishFullExpr(EUB.get(), /*DiscardedValue*/ false);
 
     // If we have a combined directive that combines 'distribute', 'for' or
     // 'simd' we need to be able to access the bounds of the schedule of the
@@ -5079,7 +5396,8 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
                                      LastIteration.get(), CombUB.get());
       CombEUB = SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, CombUB.get(),
                                    CombCondOp.get());
-      CombEUB = SemaRef.ActOnFinishFullExpr(CombEUB.get());
+      CombEUB =
+          SemaRef.ActOnFinishFullExpr(CombEUB.get(), /*DiscardedValue*/ false);
 
       const CapturedDecl *CD = cast<CapturedStmt>(AStmt)->getCapturedDecl();
       // We expect to have at least 2 more parameters than the 'parallel'
@@ -5113,7 +5431,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
             ? LB.get()
             : SemaRef.ActOnIntegerConstant(SourceLocation(), 0).get();
     Init = SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, IV.get(), RHS);
-    Init = SemaRef.ActOnFinishFullExpr(Init.get());
+    Init = SemaRef.ActOnFinishFullExpr(Init.get(), /*DiscardedValue*/ false);
 
     if (isOpenMPLoopBoundSharingDirective(DKind)) {
       Expr *CombRHS =
@@ -5124,32 +5442,40 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
               : SemaRef.ActOnIntegerConstant(SourceLocation(), 0).get();
       CombInit =
           SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, IV.get(), CombRHS);
-      CombInit = SemaRef.ActOnFinishFullExpr(CombInit.get());
+      CombInit =
+          SemaRef.ActOnFinishFullExpr(CombInit.get(), /*DiscardedValue*/ false);
     }
   }
 
   // Loop condition (IV < NumIterations) or (IV <= UB) for worksharing loops.
-  SourceLocation CondLoc = AStmt->getLocStart();
+  SourceLocation CondLoc = AStmt->getBeginLoc();
   ExprResult Cond =
       (isOpenMPWorksharingDirective(DKind) ||
        isOpenMPTaskLoopDirective(DKind) || isOpenMPDistributeDirective(DKind))
           ? SemaRef.BuildBinOp(CurScope, CondLoc, BO_LE, IV.get(), UB.get())
           : SemaRef.BuildBinOp(CurScope, CondLoc, BO_LT, IV.get(),
                                NumIterations.get());
+  ExprResult CombDistCond;
+  if (isOpenMPLoopBoundSharingDirective(DKind)) {
+    CombDistCond =
+        SemaRef.BuildBinOp(
+            CurScope, CondLoc, BO_LT, IV.get(), NumIterations.get());
+  }
+
   ExprResult CombCond;
   if (isOpenMPLoopBoundSharingDirective(DKind)) {
     CombCond =
         SemaRef.BuildBinOp(CurScope, CondLoc, BO_LE, IV.get(), CombUB.get());
   }
   // Loop increment (IV = IV + 1)
-  SourceLocation IncLoc = AStmt->getLocStart();
+  SourceLocation IncLoc = AStmt->getBeginLoc();
   ExprResult Inc =
       SemaRef.BuildBinOp(CurScope, IncLoc, BO_Add, IV.get(),
                          SemaRef.ActOnIntegerConstant(IncLoc, 1).get());
   if (!Inc.isUsable())
     return 0;
   Inc = SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, IV.get(), Inc.get());
-  Inc = SemaRef.ActOnFinishFullExpr(Inc.get());
+  Inc = SemaRef.ActOnFinishFullExpr(Inc.get(), /*DiscardedValue*/ false);
   if (!Inc.isUsable())
     return 0;
 
@@ -5167,7 +5493,8 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
     // LB = LB + ST
     NextLB =
         SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, LB.get(), NextLB.get());
-    NextLB = SemaRef.ActOnFinishFullExpr(NextLB.get());
+    NextLB =
+        SemaRef.ActOnFinishFullExpr(NextLB.get(), /*DiscardedValue*/ false);
     if (!NextLB.isUsable())
       return 0;
     // UB + ST
@@ -5177,7 +5504,8 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
     // UB = UB + ST
     NextUB =
         SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, UB.get(), NextUB.get());
-    NextUB = SemaRef.ActOnFinishFullExpr(NextUB.get());
+    NextUB =
+        SemaRef.ActOnFinishFullExpr(NextUB.get(), /*DiscardedValue*/ false);
     if (!NextUB.isUsable())
       return 0;
     if (isOpenMPLoopBoundSharingDirective(DKind)) {
@@ -5188,7 +5516,8 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
       // LB = LB + ST
       CombNextLB = SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, CombLB.get(),
                                       CombNextLB.get());
-      CombNextLB = SemaRef.ActOnFinishFullExpr(CombNextLB.get());
+      CombNextLB = SemaRef.ActOnFinishFullExpr(CombNextLB.get(),
+                                               /*DiscardedValue*/ false);
       if (!CombNextLB.isUsable())
         return 0;
       // UB + ST
@@ -5199,7 +5528,8 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
       // UB = UB + ST
       CombNextUB = SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, CombUB.get(),
                                       CombNextUB.get());
-      CombNextUB = SemaRef.ActOnFinishFullExpr(CombNextUB.get());
+      CombNextUB = SemaRef.ActOnFinishFullExpr(CombNextUB.get(),
+                                               /*DiscardedValue*/ false);
       if (!CombNextUB.isUsable())
         return 0;
     }
@@ -5209,8 +5539,8 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
   // directive with for as IV = IV + ST; ensure upper bound expression based
   // on PrevUB instead of NumIterations - used to implement 'for' when found
   // in combination with 'distribute', like in 'distribute parallel for'
-  SourceLocation DistIncLoc = AStmt->getLocStart();
-  ExprResult DistCond, DistInc, PrevEUB;
+  SourceLocation DistIncLoc = AStmt->getBeginLoc();
+  ExprResult DistCond, DistInc, PrevEUB, ParForInDistCond;
   if (isOpenMPLoopBoundSharingDirective(DKind)) {
     DistCond = SemaRef.BuildBinOp(CurScope, CondLoc, BO_LE, IV.get(), UB.get());
     assert(DistCond.isUsable() && "distribute cond expr was not built");
@@ -5220,19 +5550,26 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
     assert(DistInc.isUsable() && "distribute inc expr was not built");
     DistInc = SemaRef.BuildBinOp(CurScope, DistIncLoc, BO_Assign, IV.get(),
                                  DistInc.get());
-    DistInc = SemaRef.ActOnFinishFullExpr(DistInc.get());
+    DistInc =
+        SemaRef.ActOnFinishFullExpr(DistInc.get(), /*DiscardedValue*/ false);
     assert(DistInc.isUsable() && "distribute inc expr was not built");
 
     // Build expression: UB = min(UB, prevUB) for #for in composite or combined
     // construct
-    SourceLocation DistEUBLoc = AStmt->getLocStart();
+    SourceLocation DistEUBLoc = AStmt->getBeginLoc();
     ExprResult IsUBGreater =
         SemaRef.BuildBinOp(CurScope, DistEUBLoc, BO_GT, UB.get(), PrevUB.get());
     ExprResult CondOp = SemaRef.ActOnConditionalOp(
         DistEUBLoc, DistEUBLoc, IsUBGreater.get(), PrevUB.get(), UB.get());
     PrevEUB = SemaRef.BuildBinOp(CurScope, DistIncLoc, BO_Assign, UB.get(),
                                  CondOp.get());
-    PrevEUB = SemaRef.ActOnFinishFullExpr(PrevEUB.get());
+    PrevEUB =
+        SemaRef.ActOnFinishFullExpr(PrevEUB.get(), /*DiscardedValue*/ false);
+
+    // Build IV <= PrevUB to be used in parallel for is in combination with
+    // a distribute directive with schedule(static, 1)
+    ParForInDistCond =
+        SemaRef.BuildBinOp(CurScope, CondLoc, BO_LE, IV.get(), PrevUB.get());
   }
 
   // Build updates and final values of the loop counters.
@@ -5242,31 +5579,59 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
   Built.Updates.resize(NestedLoopCount);
   Built.Finals.resize(NestedLoopCount);
   {
-    ExprResult Div;
-    // Go from inner nested loop to outer.
-    for (int Cnt = NestedLoopCount - 1; Cnt >= 0; --Cnt) {
+    // We implement the following algorithm for obtaining the
+    // original loop iteration variable values based on the
+    // value of the collapsed loop iteration variable IV.
+    //
+    // Let n+1 be the number of collapsed loops in the nest.
+    // Iteration variables (I0, I1, .... In)
+    // Iteration counts (N0, N1, ... Nn)
+    //
+    // Acc = IV;
+    //
+    // To compute Ik for loop k, 0 <= k <= n, generate:
+    //    Prod = N(k+1) * N(k+2) * ... * Nn;
+    //    Ik = Acc / Prod;
+    //    Acc -= Ik * Prod;
+    //
+    ExprResult Acc = IV;
+    for (unsigned int Cnt = 0; Cnt < NestedLoopCount; ++Cnt) {
       LoopIterationSpace &IS = IterSpaces[Cnt];
       SourceLocation UpdLoc = IS.IncSrcRange.getBegin();
-      // Build: Iter = (IV / Div) % IS.NumIters
-      // where Div is product of previous iterations' IS.NumIters.
       ExprResult Iter;
-      if (Div.isUsable()) {
-        Iter =
-            SemaRef.BuildBinOp(CurScope, UpdLoc, BO_Div, IV.get(), Div.get());
-      } else {
-        Iter = IV;
-        assert((Cnt == (int)NestedLoopCount - 1) &&
-               "unusable div expected on first iteration only");
-      }
 
-      if (Cnt != 0 && Iter.isUsable())
-        Iter = SemaRef.BuildBinOp(CurScope, UpdLoc, BO_Rem, Iter.get(),
-                                  IS.NumIterations);
+      // Compute prod
+      ExprResult Prod =
+          SemaRef.ActOnIntegerConstant(SourceLocation(), 1).get();
+      for (unsigned int K = Cnt+1; K < NestedLoopCount; ++K)
+        Prod = SemaRef.BuildBinOp(CurScope, UpdLoc, BO_Mul, Prod.get(),
+                                  IterSpaces[K].NumIterations);
+
+      // Iter = Acc / Prod
+      // If there is at least one more inner loop to avoid
+      // multiplication by 1.
+      if (Cnt + 1 < NestedLoopCount)
+        Iter = SemaRef.BuildBinOp(CurScope, UpdLoc, BO_Div,
+                                  Acc.get(), Prod.get());
+      else
+        Iter = Acc;
       if (!Iter.isUsable()) {
         HasErrors = true;
         break;
       }
 
+      // Update Acc:
+      // Acc -= Iter * Prod
+      // Check if there is at least one more inner loop to avoid
+      // multiplication by 1.
+      if (Cnt + 1 < NestedLoopCount)
+        Prod = SemaRef.BuildBinOp(CurScope, UpdLoc, BO_Mul,
+                                  Iter.get(), Prod.get());
+      else
+        Prod = Iter;
+      Acc = SemaRef.BuildBinOp(CurScope, UpdLoc, BO_Sub,
+                               Acc.get(), Prod.get());
+
       // Build update: IS.CounterVar(Private) = IS.Start + Iter * IS.Step
       auto *VD = cast<VarDecl>(cast<DeclRefExpr>(IS.CounterVar)->getDecl());
       DeclRefExpr *CounterVar = buildDeclRefExpr(
@@ -5295,22 +5660,6 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
         break;
       }
 
-      // Build Div for the next iteration: Div <- Div * IS.NumIters
-      if (Cnt != 0) {
-        if (Div.isUnset())
-          Div = IS.NumIterations;
-        else
-          Div = SemaRef.BuildBinOp(CurScope, UpdLoc, BO_Mul, Div.get(),
-                                   IS.NumIterations);
-
-        // Add parentheses (for debugging purposes only).
-        if (Div.isUsable())
-          Div = tryBuildCapture(SemaRef, Div.get(), Captures);
-        if (!Div.isUsable()) {
-          HasErrors = true;
-          break;
-        }
-      }
       if (!Update.isUsable() || !Final.isUsable()) {
         HasErrors = true;
         break;
@@ -5331,8 +5680,10 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
   Built.IterationVarRef = IV.get();
   Built.LastIteration = LastIteration.get();
   Built.NumIterations = NumIterations.get();
-  Built.CalcLastIteration =
-      SemaRef.ActOnFinishFullExpr(CalcLastIteration.get()).get();
+  Built.CalcLastIteration = SemaRef
+                                .ActOnFinishFullExpr(CalcLastIteration.get(),
+                                                     /*DiscardedValue*/ false)
+                                .get();
   Built.PreCond = PreCond.get();
   Built.PreInits = buildPreInits(C, Captures);
   Built.Cond = Cond.get();
@@ -5356,6 +5707,8 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
   Built.DistCombinedFields.Cond = CombCond.get();
   Built.DistCombinedFields.NLB = CombNextLB.get();
   Built.DistCombinedFields.NUB = CombNextUB.get();
+  Built.DistCombinedFields.DistCond = CombDistCond.get();
+  Built.DistCombinedFields.ParForInDistCond = ParForInDistCond.get();
 
   return NestedLoopCount;
 }
@@ -5391,7 +5744,6 @@ static bool checkSimdlenSafelenSpecified(Sema &S,
   }
 
   if (Simdlen && Safelen) {
-    llvm::APSInt SimdlenRes, SafelenRes;
     const Expr *SimdlenLength = Simdlen->getSimdlen();
     const Expr *SafelenLength = Safelen->getSafelen();
     if (SimdlenLength->isValueDependent() || SimdlenLength->isTypeDependent() ||
@@ -5402,8 +5754,11 @@ static bool checkSimdlenSafelenSpecified(Sema &S,
         SafelenLength->isInstantiationDependent() ||
         SafelenLength->containsUnexpandedParameterPack())
       return false;
-    SimdlenLength->EvaluateAsInt(SimdlenRes, S.Context);
-    SafelenLength->EvaluateAsInt(SafelenRes, S.Context);
+    Expr::EvalResult SimdlenResult, SafelenResult;
+    SimdlenLength->EvaluateAsInt(SimdlenResult, S.Context);
+    SafelenLength->EvaluateAsInt(SafelenResult, S.Context);
+    llvm::APSInt SimdlenRes = SimdlenResult.Val.getInt();
+    llvm::APSInt SafelenRes = SafelenResult.Val.getInt();
     // OpenMP 4.5 [2.8.1, simd Construct, Restrictions]
     // If both simdlen and safelen clauses are specified, the value of the
     // simdlen parameter must be less than or equal to the value of the safelen
@@ -5552,7 +5907,7 @@ StmtResult Sema::ActOnOpenMPSectionsDirective(ArrayRef<OMPClause *> Clauses,
     for (Stmt *SectionStmt : llvm::make_range(std::next(S.begin()), S.end())) {
       if (!SectionStmt || !isa<OMPSectionDirective>(SectionStmt)) {
         if (SectionStmt)
-          Diag(SectionStmt->getLocStart(),
+          Diag(SectionStmt->getBeginLoc(),
                diag::err_omp_sections_substmt_not_section);
         return StmtError();
       }
@@ -5560,7 +5915,7 @@ StmtResult Sema::ActOnOpenMPSectionsDirective(ArrayRef<OMPClause *> Clauses,
           ->setHasCancel(DSAStack->isCancelRegion());
     }
   } else {
-    Diag(AStmt->getLocStart(), diag::err_omp_sections_not_compound_stmt);
+    Diag(AStmt->getBeginLoc(), diag::err_omp_sections_not_compound_stmt);
     return StmtError();
   }
 
@@ -5606,9 +5961,9 @@ StmtResult Sema::ActOnOpenMPSingleDirective(ArrayRef<OMPClause *> Clauses,
     else if (Clause->getClauseKind() == OMPC_copyprivate)
       Copyprivate = Clause;
     if (Copyprivate && Nowait) {
-      Diag(Copyprivate->getLocStart(),
+      Diag(Copyprivate->getBeginLoc(),
            diag::err_omp_single_copyprivate_with_nowait);
-      Diag(Nowait->getLocStart(), diag::note_omp_nowait_clause_here);
+      Diag(Nowait->getBeginLoc(), diag::note_omp_nowait_clause_here);
       return StmtError();
     }
   }
@@ -5644,7 +5999,7 @@ StmtResult Sema::ActOnOpenMPCriticalDirective(
   for (const OMPClause *C : Clauses) {
     if (C->getClauseKind() == OMPC_hint) {
       if (!DirName.getName()) {
-        Diag(C->getLocStart(), diag::err_omp_hint_clause_no_name);
+        Diag(C->getBeginLoc(), diag::err_omp_hint_clause_no_name);
         ErrorFound = true;
       }
       Expr *E = cast<OMPHintClause>(C)->getHint();
@@ -5653,7 +6008,7 @@ StmtResult Sema::ActOnOpenMPCriticalDirective(
         DependentHint = true;
       } else {
         Hint = E->EvaluateKnownConstInt(Context);
-        HintLoc = C->getLocStart();
+        HintLoc = C->getBeginLoc();
       }
     }
   }
@@ -5669,12 +6024,12 @@ StmtResult Sema::ActOnOpenMPCriticalDirective(
       else
         Diag(StartLoc, diag::note_omp_critical_no_hint) << 0;
       if (const auto *C = Pair.first->getSingleClause<OMPHintClause>()) {
-        Diag(C->getLocStart(), diag::note_omp_critical_hint_here)
+        Diag(C->getBeginLoc(), diag::note_omp_critical_hint_here)
             << 1
             << C->getHint()->EvaluateKnownConstInt(Context).toString(
                    /*Radix=*/10, /*Signed=*/false);
       } else {
-        Diag(Pair.first->getLocStart(), diag::note_omp_critical_no_hint) << 1;
+        Diag(Pair.first->getBeginLoc(), diag::note_omp_critical_no_hint) << 1;
       }
     }
   }
@@ -5795,7 +6150,7 @@ Sema::ActOnOpenMPParallelSectionsDirective(ArrayRef<OMPClause *> Clauses,
     for (Stmt *SectionStmt : llvm::make_range(std::next(S.begin()), S.end())) {
       if (!SectionStmt || !isa<OMPSectionDirective>(SectionStmt)) {
         if (SectionStmt)
-          Diag(SectionStmt->getLocStart(),
+          Diag(SectionStmt->getBeginLoc(),
                diag::err_omp_parallel_sections_substmt_not_section);
         return StmtError();
       }
@@ -5803,7 +6158,7 @@ Sema::ActOnOpenMPParallelSectionsDirective(ArrayRef<OMPClause *> Clauses,
           ->setHasCancel(DSAStack->isCancelRegion());
     }
   } else {
-    Diag(AStmt->getLocStart(),
+    Diag(AStmt->getBeginLoc(),
          diag::err_omp_parallel_sections_not_compound_stmt);
     return StmtError();
   }
@@ -5887,7 +6242,7 @@ StmtResult Sema::ActOnOpenMPOrderedDirective(ArrayRef<OMPClause *> Clauses,
       DependFound = C;
       if (DC->getDependencyKind() == OMPC_DEPEND_source) {
         if (DependSourceClause) {
-          Diag(C->getLocStart(), diag::err_omp_more_one_clause)
+          Diag(C->getBeginLoc(), diag::err_omp_more_one_clause)
               << getOpenMPDirectiveName(OMPD_ordered)
               << getOpenMPClauseName(OMPC_depend) << 2;
           ErrorFound = true;
@@ -5895,13 +6250,13 @@ StmtResult Sema::ActOnOpenMPOrderedDirective(ArrayRef<OMPClause *> Clauses,
           DependSourceClause = C;
         }
         if (DependSinkClause) {
-          Diag(C->getLocStart(), diag::err_omp_depend_sink_source_not_allowed)
+          Diag(C->getBeginLoc(), diag::err_omp_depend_sink_source_not_allowed)
               << 0;
           ErrorFound = true;
         }
       } else if (DC->getDependencyKind() == OMPC_DEPEND_sink) {
         if (DependSourceClause) {
-          Diag(C->getLocStart(), diag::err_omp_depend_sink_source_not_allowed)
+          Diag(C->getBeginLoc(), diag::err_omp_depend_sink_source_not_allowed)
               << 1;
           ErrorFound = true;
         }
@@ -5921,19 +6276,19 @@ StmtResult Sema::ActOnOpenMPOrderedDirective(ArrayRef<OMPClause *> Clauses,
     Diag(StartLoc, diag::err_omp_prohibited_region_simd);
     ErrorFound = true;
   } else if (DependFound && (TC || SC)) {
-    Diag(DependFound->getLocStart(), diag::err_omp_depend_clause_thread_simd)
+    Diag(DependFound->getBeginLoc(), diag::err_omp_depend_clause_thread_simd)
         << getOpenMPClauseName(TC ? TC->getClauseKind() : SC->getClauseKind());
     ErrorFound = true;
   } else if (DependFound && !DSAStack->getParentOrderedRegionParam().first) {
-    Diag(DependFound->getLocStart(),
+    Diag(DependFound->getBeginLoc(),
          diag::err_omp_ordered_directive_without_param);
     ErrorFound = true;
   } else if (TC || Clauses.empty()) {
     if (const Expr *Param = DSAStack->getParentOrderedRegionParam().first) {
-      SourceLocation ErrLoc = TC ? TC->getLocStart() : StartLoc;
+      SourceLocation ErrLoc = TC ? TC->getBeginLoc() : StartLoc;
       Diag(ErrLoc, diag::err_omp_ordered_directive_with_param)
           << (TC != nullptr);
-      Diag(Param->getLocStart(), diag::note_omp_ordered_param);
+      Diag(Param->getBeginLoc(), diag::note_omp_ordered_param);
       ErrorFound = true;
     }
   }
@@ -6154,12 +6509,12 @@ bool OpenMPAtomicUpdateChecker::checkStatement(Stmt *S, unsigned DiagId,
       }
     } else {
       ErrorFound = NotAScalarType;
-      NoteLoc = ErrorLoc = AtomicBody->getLocStart();
+      NoteLoc = ErrorLoc = AtomicBody->getBeginLoc();
       NoteRange = ErrorRange = SourceRange(NoteLoc, NoteLoc);
     }
   } else {
     ErrorFound = NotAnExpression;
-    NoteLoc = ErrorLoc = S->getLocStart();
+    NoteLoc = ErrorLoc = S->getBeginLoc();
     NoteRange = ErrorRange = SourceRange(NoteLoc, NoteLoc);
   }
   if (ErrorFound != NoError && DiagId != 0 && NoteId != 0) {
@@ -6211,13 +6566,13 @@ StmtResult Sema::ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
         C->getClauseKind() == OMPC_update ||
         C->getClauseKind() == OMPC_capture) {
       if (AtomicKind != OMPC_unknown) {
-        Diag(C->getLocStart(), diag::err_omp_atomic_several_clauses)
-            << SourceRange(C->getLocStart(), C->getLocEnd());
+        Diag(C->getBeginLoc(), diag::err_omp_atomic_several_clauses)
+            << SourceRange(C->getBeginLoc(), C->getEndLoc());
         Diag(AtomicKindLoc, diag::note_omp_atomic_previous_clause)
             << getOpenMPClauseName(AtomicKind);
       } else {
         AtomicKind = C->getClauseKind();
-        AtomicKindLoc = C->getLocStart();
+        AtomicKindLoc = C->getBeginLoc();
       }
     }
   }
@@ -6305,7 +6660,7 @@ StmtResult Sema::ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
       }
     } else {
       ErrorFound = NotAnExpression;
-      NoteLoc = ErrorLoc = Body->getLocStart();
+      NoteLoc = ErrorLoc = Body->getBeginLoc();
       NoteRange = ErrorRange = SourceRange(NoteLoc, NoteLoc);
     }
     if (ErrorFound != NoError) {
@@ -6367,7 +6722,7 @@ StmtResult Sema::ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
       }
     } else {
       ErrorFound = NotAnExpression;
-      NoteLoc = ErrorLoc = Body->getLocStart();
+      NoteLoc = ErrorLoc = Body->getBeginLoc();
       NoteRange = ErrorRange = SourceRange(NoteLoc, NoteLoc);
     }
     if (ErrorFound != NoError) {
@@ -6551,7 +6906,7 @@ StmtResult Sema::ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
               if (!FirstBinOp || FirstBinOp->getOpcode() != BO_Assign) {
                 ErrorFound = NotAnAssignmentOp;
                 NoteLoc = ErrorLoc = FirstBinOp ? FirstBinOp->getOperatorLoc()
-                                                : First->getLocStart();
+                                                : First->getBeginLoc();
                 NoteRange = ErrorRange = FirstBinOp
                                              ? FirstBinOp->getSourceRange()
                                              : SourceRange(ErrorLoc, ErrorLoc);
@@ -6561,7 +6916,7 @@ StmtResult Sema::ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
                   ErrorFound = NotAnAssignmentOp;
                   NoteLoc = ErrorLoc = SecondBinOp
                                            ? SecondBinOp->getOperatorLoc()
-                                           : Second->getLocStart();
+                                           : Second->getBeginLoc();
                   NoteRange = ErrorRange =
                       SecondBinOp ? SecondBinOp->getSourceRange()
                                   : SourceRange(ErrorLoc, ErrorLoc);
@@ -6595,15 +6950,15 @@ StmtResult Sema::ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
             }
           }
         } else {
-          NoteLoc = ErrorLoc = Body->getLocStart();
+          NoteLoc = ErrorLoc = Body->getBeginLoc();
           NoteRange = ErrorRange =
-              SourceRange(Body->getLocStart(), Body->getLocStart());
+              SourceRange(Body->getBeginLoc(), Body->getBeginLoc());
           ErrorFound = NotTwoSubstatements;
         }
       } else {
-        NoteLoc = ErrorLoc = Body->getLocStart();
+        NoteLoc = ErrorLoc = Body->getBeginLoc();
         NoteRange = ErrorRange =
-            SourceRange(Body->getLocStart(), Body->getLocStart());
+            SourceRange(Body->getBeginLoc(), Body->getBeginLoc());
         ErrorFound = NotACompoundStatement;
       }
       if (ErrorFound != NoError) {
@@ -6676,7 +7031,7 @@ StmtResult Sema::ActOnOpenMPTargetDirective(ArrayRef<OMPClause *> Clauses,
       Diag(StartLoc, diag::err_omp_target_contains_not_only_teams);
       Diag(DSAStack->getInnerTeamsRegionLoc(),
            diag::note_omp_nested_teams_construct_here);
-      Diag(S->getLocStart(), diag::note_omp_nested_statement_here)
+      Diag(S->getBeginLoc(), diag::note_omp_nested_statement_here)
           << isa<OMPExecutableDirective>(S);
       return StmtError();
     }
@@ -6980,11 +7335,11 @@ static bool checkGrainsizeNumTasksClauses(Sema &S,
       if (!PrevClause)
         PrevClause = C;
       else if (PrevClause->getClauseKind() != C->getClauseKind()) {
-        S.Diag(C->getLocStart(),
+        S.Diag(C->getBeginLoc(),
                diag::err_omp_grainsize_num_tasks_mutually_exclusive)
             << getOpenMPClauseName(C->getClauseKind())
             << getOpenMPClauseName(PrevClause->getClauseKind());
-        S.Diag(PrevClause->getLocStart(),
+        S.Diag(PrevClause->getBeginLoc(),
                diag::note_omp_previous_grainsize_num_tasks)
             << getOpenMPClauseName(PrevClause->getClauseKind());
         ErrorFound = true;
@@ -7013,9 +7368,9 @@ static bool checkReductionClauseWithNogroup(Sema &S,
     }
   }
   if (ReductionClause && NogroupClause) {
-    S.Diag(ReductionClause->getLocStart(), diag::err_omp_reduction_with_nogroup)
-        << SourceRange(NogroupClause->getLocStart(),
-                       NogroupClause->getLocEnd());
+    S.Diag(ReductionClause->getBeginLoc(), diag::err_omp_reduction_with_nogroup)
+        << SourceRange(NogroupClause->getBeginLoc(),
+                       NogroupClause->getEndLoc());
     return true;
   }
   return false;
@@ -7945,6 +8300,11 @@ OMPClause *Sema::ActOnOpenMPSingleExprClause(OpenMPClauseKind Kind, Expr *Expr,
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
+  case OMPC_unified_address:
+  case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
+  case OMPC_dynamic_allocators:
+  case OMPC_atomic_default_mem_order:
     llvm_unreachable("Clause is not allowed.");
   }
   return Res;
@@ -8030,6 +8390,7 @@ static OpenMPDirectiveKind getOpenMPCaptureRegionForClause(
     case OMPD_distribute_simd:
     case OMPD_teams_distribute:
     case OMPD_teams_distribute_simd:
+    case OMPD_requires:
       llvm_unreachable("Unexpected OpenMP directive with if-clause");
     case OMPD_unknown:
       llvm_unreachable("Unknown OpenMP directive");
@@ -8095,6 +8456,7 @@ static OpenMPDirectiveKind getOpenMPCaptureRegionForClause(
     case OMPD_distribute_simd:
     case OMPD_teams_distribute:
     case OMPD_teams_distribute_simd:
+    case OMPD_requires:
       llvm_unreachable("Unexpected OpenMP directive with num_threads-clause");
     case OMPD_unknown:
       llvm_unreachable("Unknown OpenMP directive");
@@ -8158,6 +8520,7 @@ static OpenMPDirectiveKind getOpenMPCaptureRegionForClause(
     case OMPD_ordered:
     case OMPD_atomic:
     case OMPD_distribute_simd:
+    case OMPD_requires:
       llvm_unreachable("Unexpected OpenMP directive with num_teams-clause");
     case OMPD_unknown:
       llvm_unreachable("Unknown OpenMP directive");
@@ -8221,6 +8584,7 @@ static OpenMPDirectiveKind getOpenMPCaptureRegionForClause(
     case OMPD_ordered:
     case OMPD_atomic:
     case OMPD_distribute_simd:
+    case OMPD_requires:
       llvm_unreachable("Unexpected OpenMP directive with thread_limit-clause");
     case OMPD_unknown:
       llvm_unreachable("Unknown OpenMP directive");
@@ -8284,6 +8648,7 @@ static OpenMPDirectiveKind getOpenMPCaptureRegionForClause(
     case OMPD_atomic:
     case OMPD_distribute_simd:
     case OMPD_target_teams:
+    case OMPD_requires:
       llvm_unreachable("Unexpected OpenMP directive with schedule clause");
     case OMPD_unknown:
       llvm_unreachable("Unknown OpenMP directive");
@@ -8347,6 +8712,7 @@ static OpenMPDirectiveKind getOpenMPCaptureRegionForClause(
     case OMPD_ordered:
     case OMPD_atomic:
     case OMPD_target_teams:
+    case OMPD_requires:
       llvm_unreachable("Unexpected OpenMP directive with schedule clause");
     case OMPD_unknown:
       llvm_unreachable("Unknown OpenMP directive");
@@ -8410,6 +8776,7 @@ static OpenMPDirectiveKind getOpenMPCaptureRegionForClause(
     case OMPD_ordered:
     case OMPD_atomic:
     case OMPD_distribute_simd:
+    case OMPD_requires:
       llvm_unreachable("Unexpected OpenMP directive with num_teams-clause");
     case OMPD_unknown:
       llvm_unreachable("Unknown OpenMP directive");
@@ -8459,6 +8826,11 @@ static OpenMPDirectiveKind getOpenMPCaptureRegionForClause(
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
+  case OMPC_unified_address:
+  case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
+  case OMPC_dynamic_allocators:
+  case OMPC_atomic_default_mem_order:
     llvm_unreachable("Unexpected OpenMP clause.");
   }
   return CaptureRegion;
@@ -8727,6 +9099,11 @@ OMPClause *Sema::ActOnOpenMPSimpleClause(
         static_cast<OpenMPProcBindClauseKind>(Argument), ArgumentLoc, StartLoc,
         LParenLoc, EndLoc);
     break;
+  case OMPC_atomic_default_mem_order:
+    Res = ActOnOpenMPAtomicDefaultMemOrderClause(
+        static_cast<OpenMPAtomicDefaultMemOrderClauseKind>(Argument),
+        ArgumentLoc, StartLoc, LParenLoc, EndLoc);
+    break;
   case OMPC_if:
   case OMPC_final:
   case OMPC_num_threads:
@@ -8776,6 +9153,10 @@ OMPClause *Sema::ActOnOpenMPSimpleClause(
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
+  case OMPC_unified_address:
+  case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
+  case OMPC_dynamic_allocators:
     llvm_unreachable("Clause is not allowed.");
   }
   return Res;
@@ -8848,6 +9229,21 @@ OMPClause *Sema::ActOnOpenMPProcBindClause(OpenMPProcBindClauseKind Kind,
       OMPProcBindClause(Kind, KindKwLoc, StartLoc, LParenLoc, EndLoc);
 }
 
+OMPClause *Sema::ActOnOpenMPAtomicDefaultMemOrderClause(
+    OpenMPAtomicDefaultMemOrderClauseKind Kind, SourceLocation KindKwLoc,
+    SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation EndLoc) {
+  if (Kind == OMPC_ATOMIC_DEFAULT_MEM_ORDER_unknown) {
+    Diag(KindKwLoc, diag::err_omp_unexpected_clause_value)
+        << getListOfPossibleValues(
+               OMPC_atomic_default_mem_order, /*First=*/0,
+               /*Last=*/OMPC_ATOMIC_DEFAULT_MEM_ORDER_unknown)
+        << getOpenMPClauseName(OMPC_atomic_default_mem_order);
+    return nullptr;
+  }
+  return new (Context) OMPAtomicDefaultMemOrderClause(Kind, KindKwLoc, StartLoc,
+                                                      LParenLoc, EndLoc);
+}
+
 OMPClause *Sema::ActOnOpenMPSingleExprWithArgClause(
     OpenMPClauseKind Kind, ArrayRef<unsigned> Argument, Expr *Expr,
     SourceLocation StartLoc, SourceLocation LParenLoc,
@@ -8932,6 +9328,11 @@ OMPClause *Sema::ActOnOpenMPSingleExprWithArgClause(
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
+  case OMPC_unified_address:
+  case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
+  case OMPC_dynamic_allocators:
+  case OMPC_atomic_default_mem_order:
     llvm_unreachable("Clause is not allowed.");
   }
   return Res;
@@ -9011,7 +9412,7 @@ OMPClause *Sema::ActOnOpenMPScheduleClause(
     if (!ChunkSize->isValueDependent() && !ChunkSize->isTypeDependent() &&
         !ChunkSize->isInstantiationDependent() &&
         !ChunkSize->containsUnexpandedParameterPack()) {
-      SourceLocation ChunkSizeLoc = ChunkSize->getLocStart();
+      SourceLocation ChunkSizeLoc = ChunkSize->getBeginLoc();
       ExprResult Val =
           PerformOpenMPImplicitIntegerConversion(ChunkSizeLoc, ChunkSize);
       if (Val.isInvalid())
@@ -9087,6 +9488,18 @@ OMPClause *Sema::ActOnOpenMPClause(OpenMPClauseKind Kind,
   case OMPC_nogroup:
     Res = ActOnOpenMPNogroupClause(StartLoc, EndLoc);
     break;
+  case OMPC_unified_address:
+    Res = ActOnOpenMPUnifiedAddressClause(StartLoc, EndLoc);
+    break;
+  case OMPC_unified_shared_memory:
+    Res = ActOnOpenMPUnifiedSharedMemoryClause(StartLoc, EndLoc);
+    break;
+  case OMPC_reverse_offload:
+    Res = ActOnOpenMPReverseOffloadClause(StartLoc, EndLoc);
+    break;
+  case OMPC_dynamic_allocators:
+    Res = ActOnOpenMPDynamicAllocatorsClause(StartLoc, EndLoc);
+    break;
   case OMPC_if:
   case OMPC_final:
   case OMPC_num_threads:
@@ -9126,6 +9539,7 @@ OMPClause *Sema::ActOnOpenMPClause(OpenMPClauseKind Kind,
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
+  case OMPC_atomic_default_mem_order:
     llvm_unreachable("Clause is not allowed.");
   }
   return Res;
@@ -9187,12 +9601,34 @@ OMPClause *Sema::ActOnOpenMPNogroupClause(SourceLocation StartLoc,
   return new (Context) OMPNogroupClause(StartLoc, EndLoc);
 }
 
+OMPClause *Sema::ActOnOpenMPUnifiedAddressClause(SourceLocation StartLoc,
+                                                 SourceLocation EndLoc) {
+  return new (Context) OMPUnifiedAddressClause(StartLoc, EndLoc);
+}
+
+OMPClause *Sema::ActOnOpenMPUnifiedSharedMemoryClause(SourceLocation StartLoc,
+                                                      SourceLocation EndLoc) {
+  return new (Context) OMPUnifiedSharedMemoryClause(StartLoc, EndLoc);
+}
+
+OMPClause *Sema::ActOnOpenMPReverseOffloadClause(SourceLocation StartLoc,
+                                                 SourceLocation EndLoc) {
+  return new (Context) OMPReverseOffloadClause(StartLoc, EndLoc);
+}
+
+OMPClause *Sema::ActOnOpenMPDynamicAllocatorsClause(SourceLocation StartLoc,
+                                                    SourceLocation EndLoc) {
+  return new (Context) OMPDynamicAllocatorsClause(StartLoc, EndLoc);
+}
+
 OMPClause *Sema::ActOnOpenMPVarListClause(
     OpenMPClauseKind Kind, ArrayRef<Expr *> VarList, Expr *TailExpr,
     SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation ColonLoc,
     SourceLocation EndLoc, CXXScopeSpec &ReductionIdScopeSpec,
     const DeclarationNameInfo &ReductionId, OpenMPDependClauseKind DepKind,
-    OpenMPLinearClauseKind LinKind, OpenMPMapClauseKind MapTypeModifier,
+    OpenMPLinearClauseKind LinKind,
+    ArrayRef<OpenMPMapModifierKind> MapTypeModifiers,
+    ArrayRef<SourceLocation> MapTypeModifiersLoc,
     OpenMPMapClauseKind MapType, bool IsMapTypeImplicit,
     SourceLocation DepLinMapLoc) {
   OMPClause *Res = nullptr;
@@ -9245,9 +9681,9 @@ OMPClause *Sema::ActOnOpenMPVarListClause(
                                   StartLoc, LParenLoc, EndLoc);
     break;
   case OMPC_map:
-    Res = ActOnOpenMPMapClause(MapTypeModifier, MapType, IsMapTypeImplicit,
-                               DepLinMapLoc, ColonLoc, VarList, StartLoc,
-                               LParenLoc, EndLoc);
+    Res = ActOnOpenMPMapClause(MapTypeModifiers, MapTypeModifiersLoc, MapType,
+                               IsMapTypeImplicit, DepLinMapLoc, ColonLoc,
+                               VarList, StartLoc, LParenLoc, EndLoc);
     break;
   case OMPC_to:
     Res = ActOnOpenMPToClause(VarList, StartLoc, LParenLoc, EndLoc);
@@ -9294,6 +9730,11 @@ OMPClause *Sema::ActOnOpenMPVarListClause(
   case OMPC_defaultmap:
   case OMPC_unknown:
   case OMPC_uniform:
+  case OMPC_unified_address:
+  case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
+  case OMPC_dynamic_allocators:
+  case OMPC_atomic_default_mem_order:
     llvm_unreachable("Clause is not allowed.");
   }
   return Res;
@@ -9409,6 +9850,17 @@ OMPClause *Sema::ActOnOpenMPPrivateClause(ArrayRef<Expr *> VarList,
       continue;
     Type = Type.getNonReferenceType();
 
+    // OpenMP 5.0 [2.19.3, List Item Privatization, Restrictions]
+    // A variable that is privatized must not have a const-qualified type
+    // unless it is of class type with a mutable member. This restriction does
+    // not apply to the firstprivate clause.
+    //
+    // OpenMP 3.1 [2.9.3.3, private clause, Restrictions]
+    // A variable that appears in a private clause must not have a
+    // const-qualified type unless it is of class type with a mutable member.
+    if (rejectConstNotMutableType(*this, D, Type, OMPC_private, ELoc))
+      continue;
+
     // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
     // in a Construct]
     //  Variables with the predetermined data-sharing attributes may not be
@@ -9830,6 +10282,17 @@ OMPClause *Sema::ActOnOpenMPLastprivateClause(ArrayRef<Expr *> VarList,
       continue;
     Type = Type.getNonReferenceType();
 
+    // OpenMP 5.0 [2.19.3, List Item Privatization, Restrictions]
+    // A variable that is privatized must not have a const-qualified type
+    // unless it is of class type with a mutable member. This restriction does
+    // not apply to the firstprivate clause.
+    //
+    // OpenMP 3.1 [2.9.3.5, lastprivate clause, Restrictions]
+    // A variable that appears in a lastprivate clause must not have a
+    // const-qualified type unless it is of class type with a mutable member.
+    if (rejectConstNotMutableType(*this, D, Type, OMPC_lastprivate, ELoc))
+      continue;
+
     OpenMPDirectiveKind CurrDir = DSAStack->getCurrentDirective();
     // OpenMP [2.14.1.1, Data-sharing Attribute Rules for Variables Referenced
     // in a Construct]
@@ -9895,8 +10358,8 @@ OMPClause *Sema::ActOnOpenMPLastprivateClause(ArrayRef<Expr *> VarList,
                                          PseudoDstExpr, PseudoSrcExpr);
     if (AssignmentOp.isInvalid())
       continue;
-    AssignmentOp = ActOnFinishFullExpr(AssignmentOp.get(), ELoc,
-                                       /*DiscardedValue=*/true);
+    AssignmentOp =
+        ActOnFinishFullExpr(AssignmentOp.get(), ELoc, /*DiscardedValue*/ false);
     if (AssignmentOp.isInvalid())
       continue;
 
@@ -10059,6 +10522,79 @@ static T filterLookupForUDR(SmallVectorImpl<U> &Lookups,
   return T();
 }
 
+static NamedDecl *findAcceptableDecl(Sema &SemaRef, NamedDecl *D) {
+  assert(!LookupResult::isVisible(SemaRef, D) && "not in slow case");
+
+  for (auto RD : D->redecls()) {
+    // Don't bother with extra checks if we already know this one isn't visible.
+    if (RD == D)
+      continue;
+
+    auto ND = cast<NamedDecl>(RD);
+    if (LookupResult::isVisible(SemaRef, ND))
+      return ND;
+  }
+
+  return nullptr;
+}
+
+static void
+argumentDependentLookup(Sema &SemaRef, const DeclarationNameInfo &ReductionId,
+                        SourceLocation Loc, QualType Ty,
+                        SmallVectorImpl<UnresolvedSet<8>> &Lookups) {
+  // Find all of the associated namespaces and classes based on the
+  // arguments we have.
+  Sema::AssociatedNamespaceSet AssociatedNamespaces;
+  Sema::AssociatedClassSet AssociatedClasses;
+  OpaqueValueExpr OVE(Loc, Ty, VK_LValue);
+  SemaRef.FindAssociatedClassesAndNamespaces(Loc, &OVE, AssociatedNamespaces,
+                                             AssociatedClasses);
+
+  // C++ [basic.lookup.argdep]p3:
+  //   Let X be the lookup set produced by unqualified lookup (3.4.1)
+  //   and let Y be the lookup set produced by argument dependent
+  //   lookup (defined as follows). If X contains [...] then Y is
+  //   empty. Otherwise Y is the set of declarations found in the
+  //   namespaces associated with the argument types as described
+  //   below. The set of declarations found by the lookup of the name
+  //   is the union of X and Y.
+  //
+  // Here, we compute Y and add its members to the overloaded
+  // candidate set.
+  for (auto *NS : AssociatedNamespaces) {
+    //   When considering an associated namespace, the lookup is the
+    //   same as the lookup performed when the associated namespace is
+    //   used as a qualifier (3.4.3.2) except that:
+    //
+    //     -- Any using-directives in the associated namespace are
+    //        ignored.
+    //
+    //     -- Any namespace-scope friend functions declared in
+    //        associated classes are visible within their respective
+    //        namespaces even if they are not visible during an ordinary
+    //        lookup (11.4).
+    DeclContext::lookup_result R = NS->lookup(ReductionId.getName());
+    for (auto *D : R) {
+      auto *Underlying = D;
+      if (auto *USD = dyn_cast<UsingShadowDecl>(D))
+        Underlying = USD->getTargetDecl();
+
+      if (!isa<OMPDeclareReductionDecl>(Underlying))
+        continue;
+
+      if (!SemaRef.isVisible(D)) {
+        D = findAcceptableDecl(SemaRef, D);
+        if (!D)
+          continue;
+        if (auto *USD = dyn_cast<UsingShadowDecl>(D))
+          Underlying = USD->getTargetDecl();
+      }
+      Lookups.emplace_back();
+      Lookups.back().addDecl(Underlying);
+    }
+  }
+}
+
 static ExprResult
 buildDeclareReductionRef(Sema &SemaRef, SourceLocation Loc, SourceRange Range,
                          Scope *S, CXXScopeSpec &ReductionIdScopeSpec,
@@ -10077,7 +10613,7 @@ buildDeclareReductionRef(Sema &SemaRef, SourceLocation Loc, SourceRange Range,
       } while (S && !S->isDeclScope(D));
       if (S)
         S = S->getParent();
-      Lookups.push_back(UnresolvedSet<8>());
+      Lookups.emplace_back();
       Lookups.back().append(Lookup.begin(), Lookup.end());
       Lookup.clear();
     }
@@ -10104,6 +10640,8 @@ buildDeclareReductionRef(Sema &SemaRef, SourceLocation Loc, SourceRange Range,
       })) {
     UnresolvedSet<8> ResSet;
     for (const UnresolvedSet<8> &Set : Lookups) {
+      if (Set.empty())
+        continue;
       ResSet.append(Set.begin(), Set.end());
       // The last item marks the end of all declarations at the specified scope.
       ResSet.addDecl(Set[Set.size() - 1]);
@@ -10113,6 +10651,36 @@ buildDeclareReductionRef(Sema &SemaRef, SourceLocation Loc, SourceRange Range,
         ReductionIdScopeSpec.getWithLocInContext(SemaRef.Context), ReductionId,
         /*ADL=*/true, /*Overloaded=*/true, ResSet.begin(), ResSet.end());
   }
+  // Lookup inside the classes.
+  // C++ [over.match.oper]p3:
+  //   For a unary operator @ with an operand of a type whose
+  //   cv-unqualified version is T1, and for a binary operator @ with
+  //   a left operand of a type whose cv-unqualified version is T1 and
+  //   a right operand of a type whose cv-unqualified version is T2,
+  //   three sets of candidate functions, designated member
+  //   candidates, non-member candidates and built-in candidates, are
+  //   constructed as follows:
+  //     -- If T1 is a complete class type or a class currently being
+  //        defined, the set of member candidates is the result of the
+  //        qualified lookup of T1::operator@ (13.3.1.1.1); otherwise,
+  //        the set of member candidates is empty.
+  LookupResult Lookup(SemaRef, ReductionId, Sema::LookupOMPReductionName);
+  Lookup.suppressDiagnostics();
+  if (const auto *TyRec = Ty->getAs<RecordType>()) {
+    // Complete the type if it can be completed.
+    // If the type is neither complete nor being defined, bail out now.
+    if (SemaRef.isCompleteType(Loc, Ty) || TyRec->isBeingDefined() ||
+        TyRec->getDecl()->getDefinition()) {
+      Lookup.clear();
+      SemaRef.LookupQualifiedName(Lookup, TyRec->getDecl());
+      if (Lookup.empty()) {
+        Lookups.emplace_back();
+        Lookups.back().append(Lookup.begin(), Lookup.end());
+      }
+    }
+  }
+  // Perform ADL.
+  argumentDependentLookup(SemaRef, ReductionId, Loc, Ty, Lookups);
   if (auto *VD = filterLookupForUDR<ValueDecl *>(
           Lookups, [&SemaRef, Ty](ValueDecl *D) -> ValueDecl * {
             if (!D->isInvalidDecl() &&
@@ -10219,10 +10787,11 @@ static bool checkOMPArraySectionConstantForReduction(
     SingleElement = true;
     ArraySizes.push_back(llvm::APSInt::get(1));
   } else {
-    llvm::APSInt ConstantLengthValue;
-    if (!Length->EvaluateAsInt(ConstantLengthValue, Context))
+    Expr::EvalResult Result;
+    if (!Length->EvaluateAsInt(Result, Context))
       return false;
 
+    llvm::APSInt ConstantLengthValue = Result.Val.getInt();
     SingleElement = (ConstantLengthValue.getSExtValue() == 1);
     ArraySizes.push_back(ConstantLengthValue);
   }
@@ -10243,9 +10812,12 @@ static bool checkOMPArraySectionConstantForReduction(
       // This is an array subscript which has implicit length 1!
       ArraySizes.push_back(llvm::APSInt::get(1));
     } else {
-      llvm::APSInt ConstantLengthValue;
-      if (!Length->EvaluateAsInt(ConstantLengthValue, Context) ||
-          ConstantLengthValue.getSExtValue() != 1)
+      Expr::EvalResult Result;
+      if (!Length->EvaluateAsInt(Result, Context))
+        return false;
+
+      llvm::APSInt ConstantLengthValue = Result.Val.getInt();
+      if (ConstantLengthValue.getSExtValue() != 1)
         return false;
 
       ArraySizes.push_back(ConstantLengthValue);
@@ -10430,76 +11002,71 @@ static bool actOnOMPReductionKindClause(
     // OpenMP [2.14.3.6, reduction clause, Restrictions]
     // A list item that appears in a reduction clause must not be
     // const-qualified.
-    if (Type.getNonReferenceType().isConstant(Context)) {
-      S.Diag(ELoc, diag::err_omp_const_reduction_list_item) << ERange;
-      if (!ASE && !OASE) {
-        bool IsDecl = !VD || VD->isThisDeclarationADefinition(Context) ==
-                                 VarDecl::DeclarationOnly;
-        S.Diag(D->getLocation(),
-               IsDecl ? diag::note_previous_decl : diag::note_defined_here)
-            << D;
-      }
+    if (rejectConstNotMutableType(S, D, Type, ClauseKind, ELoc,
+                                  /*AcceptIfMutable*/ false, ASE || OASE))
       continue;
-    }
+
+    OpenMPDirectiveKind CurrDir = Stack->getCurrentDirective();
     // OpenMP [2.9.3.6, Restrictions, C/C++, p.4]
     //  If a list-item is a reference type then it must bind to the same object
     //  for all threads of the team.
-    if (!ASE && !OASE && VD) {
-      VarDecl *VDDef = VD->getDefinition();
-      if (VD->getType()->isReferenceType() && VDDef && VDDef->hasInit()) {
-        DSARefChecker Check(Stack);
-        if (Check.Visit(VDDef->getInit())) {
-          S.Diag(ELoc, diag::err_omp_reduction_ref_type_arg)
-              << getOpenMPClauseName(ClauseKind) << ERange;
-          S.Diag(VDDef->getLocation(), diag::note_defined_here) << VDDef;
-          continue;
+    if (!ASE && !OASE) {
+      if (VD) {
+        VarDecl *VDDef = VD->getDefinition();
+        if (VD->getType()->isReferenceType() && VDDef && VDDef->hasInit()) {
+          DSARefChecker Check(Stack);
+          if (Check.Visit(VDDef->getInit())) {
+            S.Diag(ELoc, diag::err_omp_reduction_ref_type_arg)
+                << getOpenMPClauseName(ClauseKind) << ERange;
+            S.Diag(VDDef->getLocation(), diag::note_defined_here) << VDDef;
+            continue;
+          }
         }
       }
-    }
-
-    // OpenMP [2.14.1.1, Data-sharing Attribute Rules for Variables Referenced
-    // in a Construct]
-    //  Variables with the predetermined data-sharing attributes may not be
-    //  listed in data-sharing attributes clauses, except for the cases
-    //  listed below. For these exceptions only, listing a predetermined
-    //  variable in a data-sharing attribute clause is allowed and overrides
-    //  the variable's predetermined data-sharing attributes.
-    // OpenMP [2.14.3.6, Restrictions, p.3]
-    //  Any number of reduction clauses can be specified on the directive,
-    //  but a list item can appear only once in the reduction clauses for that
-    //  directive.
-    DSAStackTy::DSAVarData DVar = Stack->getTopDSA(D, /*FromParent=*/false);
-    if (DVar.CKind == OMPC_reduction) {
-      S.Diag(ELoc, diag::err_omp_once_referenced)
-          << getOpenMPClauseName(ClauseKind);
-      if (DVar.RefExpr)
-        S.Diag(DVar.RefExpr->getExprLoc(), diag::note_omp_referenced);
-      continue;
-    }
-    if (DVar.CKind != OMPC_unknown) {
-      S.Diag(ELoc, diag::err_omp_wrong_dsa)
-          << getOpenMPClauseName(DVar.CKind)
-          << getOpenMPClauseName(OMPC_reduction);
-      reportOriginalDsa(S, Stack, D, DVar);
-      continue;
-    }
 
-    // OpenMP [2.14.3.6, Restrictions, p.1]
-    //  A list item that appears in a reduction clause of a worksharing
-    //  construct must be shared in the parallel regions to which any of the
-    //  worksharing regions arising from the worksharing construct bind.
-    OpenMPDirectiveKind CurrDir = Stack->getCurrentDirective();
-    if (isOpenMPWorksharingDirective(CurrDir) &&
-        !isOpenMPParallelDirective(CurrDir) &&
-        !isOpenMPTeamsDirective(CurrDir)) {
-      DVar = Stack->getImplicitDSA(D, true);
-      if (DVar.CKind != OMPC_shared) {
-        S.Diag(ELoc, diag::err_omp_required_access)
-            << getOpenMPClauseName(OMPC_reduction)
-            << getOpenMPClauseName(OMPC_shared);
+      // OpenMP [2.14.1.1, Data-sharing Attribute Rules for Variables Referenced
+      // in a Construct]
+      //  Variables with the predetermined data-sharing attributes may not be
+      //  listed in data-sharing attributes clauses, except for the cases
+      //  listed below. For these exceptions only, listing a predetermined
+      //  variable in a data-sharing attribute clause is allowed and overrides
+      //  the variable's predetermined data-sharing attributes.
+      // OpenMP [2.14.3.6, Restrictions, p.3]
+      //  Any number of reduction clauses can be specified on the directive,
+      //  but a list item can appear only once in the reduction clauses for that
+      //  directive.
+      DSAStackTy::DSAVarData DVar = Stack->getTopDSA(D, /*FromParent=*/false);
+      if (DVar.CKind == OMPC_reduction) {
+        S.Diag(ELoc, diag::err_omp_once_referenced)
+            << getOpenMPClauseName(ClauseKind);
+        if (DVar.RefExpr)
+          S.Diag(DVar.RefExpr->getExprLoc(), diag::note_omp_referenced);
+        continue;
+      }
+      if (DVar.CKind != OMPC_unknown) {
+        S.Diag(ELoc, diag::err_omp_wrong_dsa)
+            << getOpenMPClauseName(DVar.CKind)
+            << getOpenMPClauseName(OMPC_reduction);
         reportOriginalDsa(S, Stack, D, DVar);
         continue;
       }
+
+      // OpenMP [2.14.3.6, Restrictions, p.1]
+      //  A list item that appears in a reduction clause of a worksharing
+      //  construct must be shared in the parallel regions to which any of the
+      //  worksharing regions arising from the worksharing construct bind.
+      if (isOpenMPWorksharingDirective(CurrDir) &&
+          !isOpenMPParallelDirective(CurrDir) &&
+          !isOpenMPTeamsDirective(CurrDir)) {
+        DVar = Stack->getImplicitDSA(D, true);
+        if (DVar.CKind != OMPC_shared) {
+          S.Diag(ELoc, diag::err_omp_required_access)
+              << getOpenMPClauseName(OMPC_reduction)
+              << getOpenMPClauseName(OMPC_shared);
+          reportOriginalDsa(S, Stack, D, DVar);
+          continue;
+        }
+      }
     }
 
     // Try to find 'declare reduction' corresponding construct before using
@@ -10518,7 +11085,7 @@ static bool actOnOMPReductionKindClause(
     }
     if (BOK == BO_Comma && DeclareReductionRef.isUnset()) {
       // Not allowed reduction identifier is found.
-      S.Diag(ReductionId.getLocStart(),
+      S.Diag(ReductionId.getBeginLoc(),
              diag::err_omp_unknown_reduction_identifier)
           << Type << ReductionIdRange;
       continue;
@@ -10771,26 +11338,27 @@ static bool actOnOMPReductionKindClause(
           ELoc, Context.getPointerType(FnTy), VK_RValue, OK_Ordinary,
           S.DefaultLvalueConversion(DeclareReductionRef.get()).get());
       Expr *Args[] = {LHS.get(), RHS.get()};
-      ReductionOp = new (Context)
-          CallExpr(Context, OVE, Args, Context.VoidTy, VK_RValue, ELoc);
+      ReductionOp =
+          CallExpr::Create(Context, OVE, Args, Context.VoidTy, VK_RValue, ELoc);
     } else {
       ReductionOp = S.BuildBinOp(
-          Stack->getCurScope(), ReductionId.getLocStart(), BOK, LHSDRE, RHSDRE);
+          Stack->getCurScope(), ReductionId.getBeginLoc(), BOK, LHSDRE, RHSDRE);
       if (ReductionOp.isUsable()) {
         if (BOK != BO_LT && BOK != BO_GT) {
           ReductionOp =
-              S.BuildBinOp(Stack->getCurScope(), ReductionId.getLocStart(),
+              S.BuildBinOp(Stack->getCurScope(), ReductionId.getBeginLoc(),
                            BO_Assign, LHSDRE, ReductionOp.get());
         } else {
           auto *ConditionalOp = new (Context)
               ConditionalOperator(ReductionOp.get(), ELoc, LHSDRE, ELoc, RHSDRE,
                                   Type, VK_LValue, OK_Ordinary);
           ReductionOp =
-              S.BuildBinOp(Stack->getCurScope(), ReductionId.getLocStart(),
+              S.BuildBinOp(Stack->getCurScope(), ReductionId.getBeginLoc(),
                            BO_Assign, LHSDRE, ConditionalOp);
         }
         if (ReductionOp.isUsable())
-          ReductionOp = S.ActOnFinishFullExpr(ReductionOp.get());
+          ReductionOp = S.ActOnFinishFullExpr(ReductionOp.get(),
+                                              /*DiscardedValue*/ false);
       }
       if (!ReductionOp.isUsable())
         continue;
@@ -10832,7 +11400,7 @@ static bool actOnOMPReductionKindClause(
           EmitError = RedId != ParentRedId;
         }
         if (EmitError) {
-          S.Diag(ReductionId.getLocStart(),
+          S.Diag(ReductionId.getBeginLoc(),
                  diag::err_omp_reduction_identifier_mismatch)
               << ReductionIdRange << RefExpr->getSourceRange();
           S.Diag(ParentSR.getBegin(),
@@ -10983,20 +11551,12 @@ bool Sema::CheckOpenMPLinearDecl(const ValueDecl *D, SourceLocation ELoc,
   }
   Type = Type.getNonReferenceType();
 
-  // A list item must not be const-qualified.
-  if (Type.isConstant(Context)) {
-    Diag(ELoc, diag::err_omp_const_variable)
-        << getOpenMPClauseName(OMPC_linear);
-    if (D) {
-      bool IsDecl =
-          !VD ||
-          VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
-      Diag(D->getLocation(),
-           IsDecl ? diag::note_previous_decl : diag::note_defined_here)
-          << D;
-    }
+  // OpenMP 5.0 [2.19.3, List Item Privatization, Restrictions]
+  // A variable that is privatized must not have a const-qualified type
+  // unless it is of class type with a mutable member. This restriction does
+  // not apply to the firstprivate clause.
+  if (rejectConstNotMutableType(*this, D, Type, OMPC_linear, ELoc))
     return true;
-  }
 
   // A list item must be of integral or pointer type.
   Type = Type.getUnqualifiedType().getCanonicalType();
@@ -11033,8 +11593,7 @@ OMPClause *Sema::ActOnOpenMPLinearClause(
     SourceLocation ELoc;
     SourceRange ERange;
     Expr *SimpleRefExpr = RefExpr;
-    auto Res = getPrivateItem(*this, SimpleRefExpr, ELoc, ERange,
-                              /*AllowArraySection=*/false);
+    auto Res = getPrivateItem(*this, SimpleRefExpr, ELoc, ERange);
     if (Res.second) {
       // It will be analyzed later.
       Vars.push_back(RefExpr);
@@ -11116,7 +11675,7 @@ OMPClause *Sema::ActOnOpenMPLinearClause(
   if (Step && !Step->isValueDependent() && !Step->isTypeDependent() &&
       !Step->isInstantiationDependent() &&
       !Step->containsUnexpandedParameterPack()) {
-    SourceLocation StepLoc = Step->getLocStart();
+    SourceLocation StepLoc = Step->getBeginLoc();
     ExprResult Val = PerformOpenMPImplicitIntegerConversion(StepLoc, Step);
     if (Val.isInvalid())
       return nullptr;
@@ -11129,7 +11688,7 @@ OMPClause *Sema::ActOnOpenMPLinearClause(
         buildDeclRefExpr(*this, SaveVar, StepExpr->getType(), StepLoc);
     ExprResult CalcStep =
         BuildBinOp(CurScope, StepLoc, BO_Assign, SaveRef.get(), StepExpr);
-    CalcStep = ActOnFinishFullExpr(CalcStep.get());
+    CalcStep = ActOnFinishFullExpr(CalcStep.get(), /*DiscardedValue*/ false);
 
     // Warn about zero linear step (it would be probably better specified as
     // making corresponding variables 'const').
@@ -11174,8 +11733,7 @@ static bool FinishOpenMPLinearClause(OMPLinearClause &Clause, DeclRefExpr *IV,
     SourceLocation ELoc;
     SourceRange ERange;
     Expr *SimpleRefExpr = RefExpr;
-    auto Res = getPrivateItem(SemaRef, SimpleRefExpr, ELoc, ERange,
-                              /*AllowArraySection=*/false);
+    auto Res = getPrivateItem(SemaRef, SimpleRefExpr, ELoc, ERange);
     ValueDecl *D = Res.first;
     if (Res.second || !D) {
       Updates.push_back(nullptr);
@@ -11217,8 +11775,8 @@ static bool FinishOpenMPLinearClause(OMPLinearClause &Clause, DeclRefExpr *IV,
                              InitExpr, IV, Step, /* Subtract */ false);
     else
       Update = *CurPrivate;
-    Update = SemaRef.ActOnFinishFullExpr(Update.get(), DE->getLocStart(),
-                                         /*DiscardedValue=*/true);
+    Update = SemaRef.ActOnFinishFullExpr(Update.get(), DE->getBeginLoc(),
+                                         /*DiscardedValue*/ false);
 
     // Build final: Var = InitExpr + NumIterations * Step
     ExprResult Final;
@@ -11228,8 +11786,8 @@ static bool FinishOpenMPLinearClause(OMPLinearClause &Clause, DeclRefExpr *IV,
                              InitExpr, NumIterations, Step, /*Subtract=*/false);
     else
       Final = *CurPrivate;
-    Final = SemaRef.ActOnFinishFullExpr(Final.get(), DE->getLocStart(),
-                                        /*DiscardedValue=*/true);
+    Final = SemaRef.ActOnFinishFullExpr(Final.get(), DE->getBeginLoc(),
+                                        /*DiscardedValue*/ false);
 
     if (!Update.isUsable() || !Final.isUsable()) {
       Updates.push_back(nullptr);
@@ -11256,8 +11814,7 @@ OMPClause *Sema::ActOnOpenMPAlignedClause(
     SourceLocation ELoc;
     SourceRange ERange;
     Expr *SimpleRefExpr = RefExpr;
-    auto Res = getPrivateItem(*this, SimpleRefExpr, ELoc, ERange,
-                              /*AllowArraySection=*/false);
+    auto Res = getPrivateItem(*this, SimpleRefExpr, ELoc, ERange);
     if (Res.second) {
       // It will be analyzed later.
       Vars.push_back(RefExpr);
@@ -11381,12 +11938,12 @@ OMPClause *Sema::ActOnOpenMPCopyinClause(ArrayRef<Expr *> VarList,
     //  operator for the class type.
     QualType ElemType = Context.getBaseElementType(Type).getNonReferenceType();
     VarDecl *SrcVD =
-        buildVarDecl(*this, DE->getLocStart(), ElemType.getUnqualifiedType(),
+        buildVarDecl(*this, DE->getBeginLoc(), ElemType.getUnqualifiedType(),
                      ".copyin.src", VD->hasAttrs() ? &VD->getAttrs() : nullptr);
     DeclRefExpr *PseudoSrcExpr = buildDeclRefExpr(
         *this, SrcVD, ElemType.getUnqualifiedType(), DE->getExprLoc());
     VarDecl *DstVD =
-        buildVarDecl(*this, DE->getLocStart(), ElemType, ".copyin.dst",
+        buildVarDecl(*this, DE->getBeginLoc(), ElemType, ".copyin.dst",
                      VD->hasAttrs() ? &VD->getAttrs() : nullptr);
     DeclRefExpr *PseudoDstExpr =
         buildDeclRefExpr(*this, DstVD, ElemType, DE->getExprLoc());
@@ -11398,7 +11955,7 @@ OMPClause *Sema::ActOnOpenMPCopyinClause(ArrayRef<Expr *> VarList,
     if (AssignmentOp.isInvalid())
       continue;
     AssignmentOp = ActOnFinishFullExpr(AssignmentOp.get(), DE->getExprLoc(),
-                                       /*DiscardedValue=*/true);
+                                       /*DiscardedValue*/ false);
     if (AssignmentOp.isInvalid())
       continue;
 
@@ -11429,8 +11986,7 @@ OMPClause *Sema::ActOnOpenMPCopyprivateClause(ArrayRef<Expr *> VarList,
     SourceLocation ELoc;
     SourceRange ERange;
     Expr *SimpleRefExpr = RefExpr;
-    auto Res = getPrivateItem(*this, SimpleRefExpr, ELoc, ERange,
-                              /*AllowArraySection=*/false);
+    auto Res = getPrivateItem(*this, SimpleRefExpr, ELoc, ERange);
     if (Res.second) {
       // It will be analyzed later.
       Vars.push_back(RefExpr);
@@ -11496,19 +12052,19 @@ OMPClause *Sema::ActOnOpenMPCopyprivateClause(ArrayRef<Expr *> VarList,
     Type = Context.getBaseElementType(Type.getNonReferenceType())
                .getUnqualifiedType();
     VarDecl *SrcVD =
-        buildVarDecl(*this, RefExpr->getLocStart(), Type, ".copyprivate.src",
+        buildVarDecl(*this, RefExpr->getBeginLoc(), Type, ".copyprivate.src",
                      D->hasAttrs() ? &D->getAttrs() : nullptr);
     DeclRefExpr *PseudoSrcExpr = buildDeclRefExpr(*this, SrcVD, Type, ELoc);
     VarDecl *DstVD =
-        buildVarDecl(*this, RefExpr->getLocStart(), Type, ".copyprivate.dst",
+        buildVarDecl(*this, RefExpr->getBeginLoc(), Type, ".copyprivate.dst",
                      D->hasAttrs() ? &D->getAttrs() : nullptr);
     DeclRefExpr *PseudoDstExpr = buildDeclRefExpr(*this, DstVD, Type, ELoc);
     ExprResult AssignmentOp = BuildBinOp(
         DSAStack->getCurScope(), ELoc, BO_Assign, PseudoDstExpr, PseudoSrcExpr);
     if (AssignmentOp.isInvalid())
       continue;
-    AssignmentOp = ActOnFinishFullExpr(AssignmentOp.get(), ELoc,
-                                       /*DiscardedValue=*/true);
+    AssignmentOp =
+        ActOnFinishFullExpr(AssignmentOp.get(), ELoc, /*DiscardedValue*/ false);
     if (AssignmentOp.isInvalid())
       continue;
 
@@ -11628,8 +12184,7 @@ Sema::ActOnOpenMPDependClause(OpenMPDependClauseKind DepKind,
       }
       SourceLocation ELoc;
       SourceRange ERange;
-      auto Res = getPrivateItem(*this, LHS, ELoc, ERange,
-                                /*AllowArraySection=*/false);
+      auto Res = getPrivateItem(*this, LHS, ELoc, ERange);
       if (Res.second) {
         // It will be analyzed later.
         Vars.push_back(RefExpr);
@@ -11770,9 +12325,11 @@ static bool checkArrayExpressionDoesNotReferToWholeSize(Sema &SemaRef,
   // If there is a lower bound that does not evaluates to zero, we are not
   // covering the whole dimension.
   if (LowerBound) {
-    llvm::APSInt ConstLowerBound;
-    if (!LowerBound->EvaluateAsInt(ConstLowerBound, SemaRef.getASTContext()))
+    Expr::EvalResult Result;
+    if (!LowerBound->EvaluateAsInt(Result, SemaRef.getASTContext()))
       return false; // Can't get the integer value as a constant.
+
+    llvm::APSInt ConstLowerBound = Result.Val.getInt();
     if (ConstLowerBound.getSExtValue())
       return true;
   }
@@ -11792,10 +12349,11 @@ static bool checkArrayExpressionDoesNotReferToWholeSize(Sema &SemaRef,
   if (!CATy)
     return false;
 
-  llvm::APSInt ConstLength;
-  if (!Length->EvaluateAsInt(ConstLength, SemaRef.getASTContext()))
+  Expr::EvalResult Result;
+  if (!Length->EvaluateAsInt(Result, SemaRef.getASTContext()))
     return false; // Can't get the integer value as a constant.
 
+  llvm::APSInt ConstLength = Result.Val.getInt();
   return CATy->getSize().getSExtValue() != ConstLength.getSExtValue();
 }
 
@@ -11826,10 +12384,11 @@ static bool checkArrayExpressionDoesNotReferToUnitySize(Sema &SemaRef,
   }
 
   // Check if the length evaluates to 1.
-  llvm::APSInt ConstLength;
-  if (!Length->EvaluateAsInt(ConstLength, SemaRef.getASTContext()))
+  Expr::EvalResult Result;
+  if (!Length->EvaluateAsInt(Result, SemaRef.getASTContext()))
     return false; // Can't get the integer value as a constant.
 
+  llvm::APSInt ConstLength = Result.Val.getInt();
   return ConstLength.getSExtValue() != 1;
 }
 
@@ -11986,6 +12545,19 @@ static const Expr *checkMapClauseExpressionBase(
                                                       E->getType()))
         AllowWholeSizeArraySection = false;
 
+      if (const auto *TE = dyn_cast<CXXThisExpr>(E)) {
+        Expr::EvalResult Result;
+        if (CurE->getIdx()->EvaluateAsInt(Result, SemaRef.getASTContext())) {
+          if (!Result.Val.getInt().isNullValue()) {
+            SemaRef.Diag(CurE->getIdx()->getExprLoc(),
+                         diag::err_omp_invalid_map_this_expr);
+            SemaRef.Diag(CurE->getIdx()->getExprLoc(),
+                         diag::note_omp_invalid_subscript_on_this_ptr_map);
+          }
+        }
+        RelevantExpr = TE;
+      }
+
       // Record the component - we don't have any declaration associated.
       CurComponents.emplace_back(CurE, nullptr);
     } else if (auto *CurE = dyn_cast<OMPArraySectionExpr>(E)) {
@@ -12032,6 +12604,30 @@ static const Expr *checkMapClauseExpressionBase(
         return nullptr;
       }
 
+      if (const auto *TE = dyn_cast<CXXThisExpr>(E)) {
+        Expr::EvalResult ResultR;
+        Expr::EvalResult ResultL;
+        if (CurE->getLength()->EvaluateAsInt(ResultR,
+                                             SemaRef.getASTContext())) {
+          if (!ResultR.Val.getInt().isOneValue()) {
+            SemaRef.Diag(CurE->getLength()->getExprLoc(),
+                         diag::err_omp_invalid_map_this_expr);
+            SemaRef.Diag(CurE->getLength()->getExprLoc(),
+                         diag::note_omp_invalid_length_on_this_ptr_mapping);
+          }
+        }
+        if (CurE->getLowerBound() && CurE->getLowerBound()->EvaluateAsInt(
+                                        ResultL, SemaRef.getASTContext())) {
+          if (!ResultL.Val.getInt().isNullValue()) {
+            SemaRef.Diag(CurE->getLowerBound()->getExprLoc(),
+                         diag::err_omp_invalid_map_this_expr);
+            SemaRef.Diag(CurE->getLowerBound()->getExprLoc(),
+                         diag::note_omp_invalid_lower_bound_on_this_ptr_mapping);
+          }
+        }
+        RelevantExpr = TE;
+      }
+
       // Record the component - we don't have any declaration associated.
       CurComponents.emplace_back(CurE, nullptr);
     } else {
@@ -12219,6 +12815,26 @@ static bool checkMapConflicts(
         // An expression is a subset of the other.
         if (CurrentRegionOnly && (CI == CE || SI == SE)) {
           if (CKind == OMPC_map) {
+            if (CI != CE || SI != SE) {
+              // Allow constructs like this: map(s, s.ptr[0:1]), where s.ptr is
+              // a pointer.
+              auto Begin =
+                  CI != CE ? CurComponents.begin() : StackComponents.begin();
+              auto End = CI != CE ? CurComponents.end() : StackComponents.end();
+              auto It = Begin;
+              while (It != End && !It->getAssociatedDeclaration())
+                std::advance(It, 1);
+              assert(It != End &&
+                     "Expected at least one component with the declaration.");
+              if (It != Begin && It->getAssociatedDeclaration()
+                                     ->getType()
+                                     .getCanonicalType()
+                                     ->isAnyPointerType()) {
+                IsEnclosedByDataEnvironmentExpr = false;
+                EnclosingExpr = nullptr;
+                return false;
+              }
+            }
             SemaRef.Diag(ELoc, diag::err_omp_map_shared_storage) << ERange;
           } else {
             assert(CKind == OMPC_to || CKind == OMPC_from);
@@ -12349,6 +12965,18 @@ checkMappableExpressionList(Sema &SemaRef, DSAStackTy *DSAS,
     assert(!CurComponents.empty() &&
            "Invalid mappable expression information.");
 
+    if (const auto *TE = dyn_cast<CXXThisExpr>(BE)) {
+      // Add store "this" pointer to class in DSAStackTy for future checking
+      DSAS->addMappedClassesQualTypes(TE->getType());
+      // Skip restriction checking for variable or field declarations
+      MVLI.ProcessedVarList.push_back(RE);
+      MVLI.VarComponents.resize(MVLI.VarComponents.size() + 1);
+      MVLI.VarComponents.back().append(CurComponents.begin(),
+                                       CurComponents.end());
+      MVLI.VarBaseDeclarations.push_back(nullptr);
+      continue;
+    }
+
     // For the following checks, we rely on the base declaration which is
     // expected to be associated with the last component. The declaration is
     // expected to be a variable or a field (if 'this' is being mapped).
@@ -12478,7 +13106,8 @@ checkMappableExpressionList(Sema &SemaRef, DSAStackTy *DSAS,
 }
 
 OMPClause *
-Sema::ActOnOpenMPMapClause(OpenMPMapClauseKind MapTypeModifier,
+Sema::ActOnOpenMPMapClause(ArrayRef<OpenMPMapModifierKind> MapTypeModifiers,
+                           ArrayRef<SourceLocation> MapTypeModifiersLoc,
                            OpenMPMapClauseKind MapType, bool IsMapTypeImplicit,
                            SourceLocation MapLoc, SourceLocation ColonLoc,
                            ArrayRef<Expr *> VarList, SourceLocation StartLoc,
@@ -12487,12 +13116,31 @@ Sema::ActOnOpenMPMapClause(OpenMPMapClauseKind MapTypeModifier,
   checkMappableExpressionList(*this, DSAStack, OMPC_map, MVLI, StartLoc,
                               MapType, IsMapTypeImplicit);
 
+  OpenMPMapModifierKind Modifiers[] = { OMPC_MAP_MODIFIER_unknown,
+                                        OMPC_MAP_MODIFIER_unknown };
+  SourceLocation ModifiersLoc[OMPMapClause::NumberOfModifiers];
+
+  // Process map-type-modifiers, flag errors for duplicate modifiers.
+  unsigned Count = 0;
+  for (unsigned I = 0, E = MapTypeModifiers.size(); I < E; ++I) {
+    if (MapTypeModifiers[I] != OMPC_MAP_MODIFIER_unknown &&
+        llvm::find(Modifiers, MapTypeModifiers[I]) != std::end(Modifiers)) {
+      Diag(MapTypeModifiersLoc[I], diag::err_omp_duplicate_map_type_modifier);
+      continue;
+    }
+    assert(Count < OMPMapClause::NumberOfModifiers &&
+           "Modifiers exceed the allowed number of map type modifiers");
+    Modifiers[Count] = MapTypeModifiers[I];
+    ModifiersLoc[Count] = MapTypeModifiersLoc[I];
+    ++Count;
+  }
+
   // We need to produce a map clause even if we don't have variables so that
   // other diagnostics related with non-existing map clauses are accurate.
   return OMPMapClause::Create(Context, StartLoc, LParenLoc, EndLoc,
                               MVLI.ProcessedVarList, MVLI.VarBaseDeclarations,
-                              MVLI.VarComponents, MapTypeModifier, MapType,
-                              IsMapTypeImplicit, MapLoc);
+                              MVLI.VarComponents, Modifiers, ModifiersLoc,
+                              MapType, IsMapTypeImplicit, MapLoc);
 }
 
 QualType Sema::ActOnOpenMPDeclareReductionType(SourceLocation TyLoc,
@@ -12649,6 +13297,11 @@ void Sema::ActOnOpenMPDeclareReductionCombinerStart(Scope *S, Decl *D) {
     DRD->addDecl(OmpInParm);
     DRD->addDecl(OmpOutParm);
   }
+  Expr *InE =
+      ::buildDeclRefExpr(*this, OmpInParm, ReductionType, D->getLocation());
+  Expr *OutE =
+      ::buildDeclRefExpr(*this, OmpOutParm, ReductionType, D->getLocation());
+  DRD->setCombinerData(InE, OutE);
 }
 
 void Sema::ActOnOpenMPDeclareReductionCombinerEnd(Decl *D, Expr *Combiner) {
@@ -12704,6 +13357,11 @@ VarDecl *Sema::ActOnOpenMPDeclareReductionInitializerStart(Scope *S, Decl *D) {
     DRD->addDecl(OmpPrivParm);
     DRD->addDecl(OmpOrigParm);
   }
+  Expr *OrigE =
+      ::buildDeclRefExpr(*this, OmpOrigParm, ReductionType, D->getLocation());
+  Expr *PrivE =
+      ::buildDeclRefExpr(*this, OmpPrivParm, ReductionType, D->getLocation());
+  DRD->setInitializerData(OrigE, PrivE);
   return OmpPrivParm;
 }
 
@@ -12875,7 +13533,7 @@ OMPClause *Sema::ActOnOpenMPDistScheduleClause(
     if (!ChunkSize->isValueDependent() && !ChunkSize->isTypeDependent() &&
         !ChunkSize->isInstantiationDependent() &&
         !ChunkSize->containsUnexpandedParameterPack()) {
-      SourceLocation ChunkSizeLoc = ChunkSize->getLocStart();
+      SourceLocation ChunkSizeLoc = ChunkSize->getBeginLoc();
       ExprResult Val =
           PerformOpenMPImplicitIntegerConversion(ChunkSizeLoc, ChunkSize);
       if (Val.isInvalid())
@@ -12951,19 +13609,14 @@ bool Sema::ActOnStartOpenMPDeclareTargetDirective(SourceLocation Loc) {
     Diag(Loc, diag::err_omp_region_not_file_context);
     return false;
   }
-  if (IsInOpenMPDeclareTargetContext) {
-    Diag(Loc, diag::err_omp_enclosed_declare_target);
-    return false;
-  }
-
-  IsInOpenMPDeclareTargetContext = true;
+  ++DeclareTargetNestingLevel;
   return true;
 }
 
 void Sema::ActOnFinishOpenMPDeclareTargetDirective() {
-  assert(IsInOpenMPDeclareTargetContext &&
+  assert(DeclareTargetNestingLevel > 0 &&
          "Unexpected ActOnFinishOpenMPDeclareTargetDirective");
-  IsInOpenMPDeclareTargetContext = false;
+  --DeclareTargetNestingLevel;
 }
 
 void Sema::ActOnOpenMPDeclareTargetName(Scope *CurScope,
@@ -12994,16 +13647,20 @@ void Sema::ActOnOpenMPDeclareTargetName(Scope *CurScope,
   }
 
   NamedDecl *ND = Lookup.getAsSingle<NamedDecl>();
-  if (isa<VarDecl>(ND) || isa<FunctionDecl>(ND)) {
+  if (isa<VarDecl>(ND) || isa<FunctionDecl>(ND) ||
+      isa<FunctionTemplateDecl>(ND)) {
     if (!SameDirectiveDecls.insert(cast<NamedDecl>(ND->getCanonicalDecl())))
       Diag(Id.getLoc(), diag::err_omp_declare_target_multiple) << Id.getName();
-    if (!ND->hasAttr<OMPDeclareTargetDeclAttr>()) {
+    llvm::Optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
+        OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(
+            cast<ValueDecl>(ND));
+    if (!Res) {
       auto *A = OMPDeclareTargetDeclAttr::CreateImplicit(Context, MT);
       ND->addAttr(A);
       if (ASTMutationListener *ML = Context.getASTMutationListener())
         ML->DeclarationMarkedOpenMPDeclareTarget(ND, A);
       checkDeclIsAllowedInOpenMPTarget(nullptr, ND, Id.getLoc());
-    } else if (ND->getAttr<OMPDeclareTargetDeclAttr>()->getMapType() != MT) {
+    } else if (*Res != MT) {
       Diag(Id.getLoc(), diag::err_omp_declare_target_to_and_link)
           << Id.getName();
     }
@@ -13014,79 +13671,13 @@ void Sema::ActOnOpenMPDeclareTargetName(Scope *CurScope,
 
 static void checkDeclInTargetContext(SourceLocation SL, SourceRange SR,
                                      Sema &SemaRef, Decl *D) {
-  if (!D)
+  if (!D || !isa<VarDecl>(D))
     return;
-  const Decl *LD = nullptr;
-  if (isa<TagDecl>(D)) {
-    LD = cast<TagDecl>(D)->getDefinition();
-  } else if (isa<VarDecl>(D)) {
-    LD = cast<VarDecl>(D)->getDefinition();
-
-    // If this is an implicit variable that is legal and we do not need to do
-    // anything.
-    if (cast<VarDecl>(D)->isImplicit()) {
-      auto *A = OMPDeclareTargetDeclAttr::CreateImplicit(
-          SemaRef.Context, OMPDeclareTargetDeclAttr::MT_To);
-      D->addAttr(A);
-      if (ASTMutationListener *ML = SemaRef.Context.getASTMutationListener())
-        ML->DeclarationMarkedOpenMPDeclareTarget(D, A);
-      return;
-    }
-  } else if (const auto *F = dyn_cast<FunctionDecl>(D)) {
-    const FunctionDecl *FD = nullptr;
-    if (cast<FunctionDecl>(D)->hasBody(FD)) {
-      LD = FD;
-      // If the definition is associated with the current declaration in the
-      // target region (it can be e.g. a lambda) that is legal and we do not
-      // need to do anything else.
-      if (LD == D) {
-        auto *A = OMPDeclareTargetDeclAttr::CreateImplicit(
-            SemaRef.Context, OMPDeclareTargetDeclAttr::MT_To);
-        D->addAttr(A);
-        if (ASTMutationListener *ML = SemaRef.Context.getASTMutationListener())
-          ML->DeclarationMarkedOpenMPDeclareTarget(D, A);
-        return;
-      }
-    } else if (F->isFunctionTemplateSpecialization() &&
-               F->getTemplateSpecializationKind() ==
-                   TSK_ImplicitInstantiation) {
-      // Check if the function is implicitly instantiated from the template
-      // defined in the declare target region.
-      const FunctionTemplateDecl *FTD = F->getPrimaryTemplate();
-      if (FTD && FTD->hasAttr<OMPDeclareTargetDeclAttr>())
-        return;
-    }
-  }
-  if (!LD)
-    LD = D;
-  if (LD && !LD->hasAttr<OMPDeclareTargetDeclAttr>() &&
-      ((isa<VarDecl>(LD) && !isa<ParmVarDecl>(LD)) || isa<FunctionDecl>(LD))) {
-    // Outlined declaration is not declared target.
-    if (!isa<FunctionDecl>(LD)) {
-      if (LD->isOutOfLine()) {
-        SemaRef.Diag(LD->getLocation(), diag::warn_omp_not_in_target_context);
-        SemaRef.Diag(SL, diag::note_used_here) << SR;
-      } else {
-        const DeclContext *DC = LD->getDeclContext();
-        while (DC &&
-               (!isa<FunctionDecl>(DC) ||
-                !cast<FunctionDecl>(DC)->hasAttr<OMPDeclareTargetDeclAttr>()))
-          DC = DC->getParent();
-        if (DC)
-          return;
-
-        // Is not declared in target context.
-        SemaRef.Diag(LD->getLocation(), diag::warn_omp_not_in_target_context);
-        SemaRef.Diag(SL, diag::note_used_here) << SR;
-      }
-    }
-    // Mark decl as declared target to prevent further diagnostic.
-    auto *A = OMPDeclareTargetDeclAttr::CreateImplicit(
-        SemaRef.Context, OMPDeclareTargetDeclAttr::MT_To);
-    D->addAttr(A);
-    if (ASTMutationListener *ML = SemaRef.Context.getASTMutationListener())
-      ML->DeclarationMarkedOpenMPDeclareTarget(D, A);
-  }
+  auto *VD = cast<VarDecl>(D);
+  if (OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD))
+    return;
+  SemaRef.Diag(VD->getLocation(), diag::warn_omp_not_in_target_context);
+  SemaRef.Diag(SL, diag::note_used_here) << SR;
 }
 
 static bool checkValueDeclInTarget(SourceLocation SL, SourceRange SR,
@@ -13102,10 +13693,11 @@ void Sema::checkDeclIsAllowedInOpenMPTarget(Expr *E, Decl *D,
   if (!D || D->isInvalidDecl())
     return;
   SourceRange SR = E ? E->getSourceRange() : D->getSourceRange();
-  SourceLocation SL = E ? E->getLocStart() : D->getLocation();
+  SourceLocation SL = E ? E->getBeginLoc() : D->getLocation();
   if (auto *VD = dyn_cast<VarDecl>(D)) {
     // Only global variables can be marked as declare target.
-    if (VD->isLocalVarDeclOrParm())
+    if (!VD->isFileVarDecl() && !VD->isStaticLocal() &&
+        !VD->isStaticDataMember())
       return;
     // 2.10.6: threadprivate variable cannot appear in a declare target
     // directive.
@@ -13115,48 +13707,39 @@ void Sema::checkDeclIsAllowedInOpenMPTarget(Expr *E, Decl *D,
       return;
     }
   }
+  if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(D))
+    D = FTD->getTemplatedDecl();
+  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
+    llvm::Optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
+        OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(FD);
+    if (Res && *Res == OMPDeclareTargetDeclAttr::MT_Link) {
+      assert(IdLoc.isValid() && "Source location is expected");
+      Diag(IdLoc, diag::err_omp_function_in_link_clause);
+      Diag(FD->getLocation(), diag::note_defined_here) << FD;
+      return;
+    }
+  }
   if (auto *VD = dyn_cast<ValueDecl>(D)) {
     // Problem if any with var declared with incomplete type will be reported
     // as normal, so no need to check it here.
     if ((E || !VD->getType()->isIncompleteType()) &&
-        !checkValueDeclInTarget(SL, SR, *this, DSAStack, VD)) {
-      // Mark decl as declared target to prevent further diagnostic.
-      if (isa<VarDecl>(VD) || isa<FunctionDecl>(VD) ||
-          isa<FunctionTemplateDecl>(VD)) {
+        !checkValueDeclInTarget(SL, SR, *this, DSAStack, VD))
+      return;
+    if (!E && !OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD)) {
+      // Checking declaration inside declare target region.
+      if (isa<VarDecl>(D) || isa<FunctionDecl>(D) ||
+          isa<FunctionTemplateDecl>(D)) {
         auto *A = OMPDeclareTargetDeclAttr::CreateImplicit(
             Context, OMPDeclareTargetDeclAttr::MT_To);
-        VD->addAttr(A);
+        D->addAttr(A);
         if (ASTMutationListener *ML = Context.getASTMutationListener())
-          ML->DeclarationMarkedOpenMPDeclareTarget(VD, A);
+          ML->DeclarationMarkedOpenMPDeclareTarget(D, A);
       }
       return;
     }
   }
-  if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(D))
-    D = FTD->getTemplatedDecl();
-  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
-    if (FD->hasAttr<OMPDeclareTargetDeclAttr>() &&
-        (FD->getAttr<OMPDeclareTargetDeclAttr>()->getMapType() ==
-         OMPDeclareTargetDeclAttr::MT_Link)) {
-      assert(IdLoc.isValid() && "Source location is expected");
-      Diag(IdLoc, diag::err_omp_function_in_link_clause);
-      Diag(FD->getLocation(), diag::note_defined_here) << FD;
-      return;
-    }
-  }
-  if (!E) {
-    // Checking declaration inside declare target region.
-    if (!D->hasAttr<OMPDeclareTargetDeclAttr>() &&
-        (isa<VarDecl>(D) || isa<FunctionDecl>(D) ||
-         isa<FunctionTemplateDecl>(D))) {
-      auto *A = OMPDeclareTargetDeclAttr::CreateImplicit(
-          Context, OMPDeclareTargetDeclAttr::MT_To);
-      D->addAttr(A);
-      if (ASTMutationListener *ML = Context.getASTMutationListener())
-        ML->DeclarationMarkedOpenMPDeclareTarget(D, A);
-    }
+  if (!E)
     return;
-  }
   checkDeclInTargetContext(E->getExprLoc(), E->getSourceRange(), *this, D);
 }