SemaOpenMP.cpp

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//===--- SemaOpenMP.cpp - Semantic Analysis for OpenMP constructs ---------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements semantic analysis for OpenMP directives and
/// clauses.
///
//===----------------------------------------------------------------------===//

#include "TreeTransform.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclOpenMP.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/StmtOpenMP.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/OpenMPKinds.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaInternal.h"
#include "llvm/ADT/PointerEmbeddedInt.h"
using namespace clang;

//===----------------------------------------------------------------------===//
// Stack of data-sharing attributes for variables
//===----------------------------------------------------------------------===//

static const Expr *checkMapClauseExpressionBase(
    Sema &SemaRef, Expr *E,
    OMPClauseMappableExprCommon::MappableExprComponentList &CurComponents,
    OpenMPClauseKind CKind, bool NoDiagnose);

namespace {
/// Default data sharing attributes, which can be applied to directive.
enum DefaultDataSharingAttributes {
  DSA_unspecified = 0, /// Data sharing attribute not specified.
  DSA_none = 1 << 0,   /// Default data sharing attribute 'none'.
  DSA_shared = 1 << 1, /// Default data sharing attribute 'shared'.
};

/// Attributes of the defaultmap clause.
enum DefaultMapAttributes {
  DMA_unspecified,   /// Default mapping is not specified.
  DMA_tofrom_scalar, /// Default mapping is 'tofrom:scalar'.
};

/// Stack for tracking declarations used in OpenMP directives and
/// clauses and their data-sharing attributes.
class DSAStackTy {
public:
  struct DSAVarData {
    OpenMPDirectiveKind DKind = OMPD_unknown;
    OpenMPClauseKind CKind = OMPC_unknown;
    const Expr *RefExpr = nullptr;
    DeclRefExpr *PrivateCopy = nullptr;
    SourceLocation ImplicitDSALoc;
    DSAVarData() = default;
    DSAVarData(OpenMPDirectiveKind DKind, OpenMPClauseKind CKind,
               const Expr *RefExpr, DeclRefExpr *PrivateCopy,
               SourceLocation ImplicitDSALoc)
        : DKind(DKind), CKind(CKind), RefExpr(RefExpr),
          PrivateCopy(PrivateCopy), ImplicitDSALoc(ImplicitDSALoc) {}
  };
  using OperatorOffsetTy =
      llvm::SmallVector<std::pair<Expr *, OverloadedOperatorKind>, 4>;
  using DoacrossDependMapTy =
      llvm::DenseMap<OMPDependClause *, OperatorOffsetTy>;

private:
  struct DSAInfo {
    OpenMPClauseKind Attributes = OMPC_unknown;
    /// Pointer to a reference expression and a flag which shows that the
    /// variable is marked as lastprivate(true) or not (false).
    llvm::PointerIntPair<const Expr *, 1, bool> RefExpr;
    DeclRefExpr *PrivateCopy = nullptr;
  };
  using DeclSAMapTy = llvm::SmallDenseMap<const ValueDecl *, DSAInfo, 8>;
  using AlignedMapTy = llvm::SmallDenseMap<const ValueDecl *, const Expr *, 8>;
  using LCDeclInfo = std::pair<unsigned, VarDecl *>;
  using LoopControlVariablesMapTy =
      llvm::SmallDenseMap<const ValueDecl *, LCDeclInfo, 8>;
  /// Struct that associates a component with the clause kind where they are
  /// found.
  struct MappedExprComponentTy {
    OMPClauseMappableExprCommon::MappableExprComponentLists Components;
    OpenMPClauseKind Kind = OMPC_unknown;
  };
  using MappedExprComponentsTy =
      llvm::DenseMap<const ValueDecl *, MappedExprComponentTy>;
  using CriticalsWithHintsTy =
      llvm::StringMap<std::pair<const OMPCriticalDirective *, llvm::APSInt>>;
  struct ReductionData {
    using BOKPtrType = llvm::PointerEmbeddedInt<BinaryOperatorKind, 16>;
    SourceRange ReductionRange;
    llvm::PointerUnion<const Expr *, BOKPtrType> ReductionOp;
    ReductionData() = default;
    void set(BinaryOperatorKind BO, SourceRange RR) {
      ReductionRange = RR;
      ReductionOp = BO;
    }
    void set(const Expr *RefExpr, SourceRange RR) {
      ReductionRange = RR;
      ReductionOp = RefExpr;
    }
  };
  using DeclReductionMapTy =
      llvm::SmallDenseMap<const ValueDecl *, ReductionData, 4>;

  struct SharingMapTy {
    DeclSAMapTy SharingMap;
    DeclReductionMapTy ReductionMap;
    AlignedMapTy AlignedMap;
    MappedExprComponentsTy MappedExprComponents;
    LoopControlVariablesMapTy LCVMap;
    DefaultDataSharingAttributes DefaultAttr = DSA_unspecified;
    SourceLocation DefaultAttrLoc;
    DefaultMapAttributes DefaultMapAttr = DMA_unspecified;
    SourceLocation DefaultMapAttrLoc;
    OpenMPDirectiveKind Directive = OMPD_unknown;
    DeclarationNameInfo DirectiveName;
    Scope *CurScope = nullptr;
    SourceLocation ConstructLoc;
    /// Set of 'depend' clauses with 'sink|source' dependence kind. Required to
    /// get the data (loop counters etc.) about enclosing loop-based construct.
    /// This data is required during codegen.
    DoacrossDependMapTy DoacrossDepends;
    /// first argument (Expr *) contains optional argument of the
    /// 'ordered' clause, the second one is true if the regions has 'ordered'
    /// clause, false otherwise.
    llvm::Optional<std::pair<const Expr *, OMPOrderedClause *>> OrderedRegion;
    bool NowaitRegion = false;
    bool CancelRegion = false;
    unsigned AssociatedLoops = 1;
    SourceLocation InnerTeamsRegionLoc;
    /// Reference to the taskgroup task_reduction reference expression.
    Expr *TaskgroupReductionRef = nullptr;
    SharingMapTy(OpenMPDirectiveKind DKind, DeclarationNameInfo Name,
                 Scope *CurScope, SourceLocation Loc)
        : Directive(DKind), DirectiveName(Name), CurScope(CurScope),
          ConstructLoc(Loc) {}
    SharingMapTy() = default;
  };

  using StackTy = SmallVector<SharingMapTy, 4>;

  /// Stack of used declaration and their data-sharing attributes.
  DeclSAMapTy Threadprivates;
  const FunctionScopeInfo *CurrentNonCapturingFunctionScope = nullptr;
  SmallVector<std::pair<StackTy, const FunctionScopeInfo *>, 4> Stack;
  /// true, if check for DSA must be from parent directive, false, if
  /// from current directive.
  OpenMPClauseKind ClauseKindMode = OMPC_unknown;
  Sema &SemaRef;
  bool ForceCapturing = false;
  CriticalsWithHintsTy Criticals;

  using iterator = StackTy::const_reverse_iterator;

  DSAVarData getDSA(iterator &Iter, ValueDecl *D) const;

  /// Checks if the variable is a local for OpenMP region.
  bool isOpenMPLocal(VarDecl *D, iterator Iter) const;

  bool isStackEmpty() const {
    return Stack.empty() ||
           Stack.back().second != CurrentNonCapturingFunctionScope ||
           Stack.back().first.empty();
  }

  /// Vector of previously declared requires directives
  SmallVector<const OMPRequiresDecl *, 2> RequiresDecls;

public:
  explicit DSAStackTy(Sema &S) : SemaRef(S) {}

  bool isClauseParsingMode() const { return ClauseKindMode != OMPC_unknown; }
  OpenMPClauseKind getClauseParsingMode() const {
    assert(isClauseParsingMode() && "Must be in clause parsing mode.");
    return ClauseKindMode;
  }
  void setClauseParsingMode(OpenMPClauseKind K) { ClauseKindMode = K; }

  bool isForceVarCapturing() const { return ForceCapturing; }
  void setForceVarCapturing(bool V) { ForceCapturing = V; }

  void push(OpenMPDirectiveKind DKind, const DeclarationNameInfo &DirName,
            Scope *CurScope, SourceLocation Loc) {
    if (Stack.empty() ||
        Stack.back().second != CurrentNonCapturingFunctionScope)
      Stack.emplace_back(StackTy(), CurrentNonCapturingFunctionScope);
    Stack.back().first.emplace_back(DKind, DirName, CurScope, Loc);
    Stack.back().first.back().DefaultAttrLoc = Loc;
  }

  void pop() {
    assert(!Stack.back().first.empty() &&
           "Data-sharing attributes stack is empty!");
    Stack.back().first.pop_back();
  }

  /// Start new OpenMP region stack in new non-capturing function.
  void pushFunction() {
    const FunctionScopeInfo *CurFnScope = SemaRef.getCurFunction();
    assert(!isa<CapturingScopeInfo>(CurFnScope));
    CurrentNonCapturingFunctionScope = CurFnScope;
  }
  /// Pop region stack for non-capturing function.
  void popFunction(const FunctionScopeInfo *OldFSI) {
    if (!Stack.empty() && Stack.back().second == OldFSI) {
      assert(Stack.back().first.empty());
      Stack.pop_back();
    }
    CurrentNonCapturingFunctionScope = nullptr;
    for (const FunctionScopeInfo *FSI : llvm::reverse(SemaRef.FunctionScopes)) {
      if (!isa<CapturingScopeInfo>(FSI)) {
        CurrentNonCapturingFunctionScope = FSI;
        break;
      }
    }
  }

  void addCriticalWithHint(const OMPCriticalDirective *D, llvm::APSInt Hint) {
    Criticals.try_emplace(D->getDirectiveName().getAsString(), D, Hint);
  }
  const std::pair<const OMPCriticalDirective *, llvm::APSInt>
  getCriticalWithHint(const DeclarationNameInfo &Name) const {
    auto I = Criticals.find(Name.getAsString());
    if (I != Criticals.end())
      return I->second;
    return std::make_pair(nullptr, llvm::APSInt());
  }
  /// If 'aligned' declaration for given variable \a D was not seen yet,
  /// add it and return NULL; otherwise return previous occurrence's expression
  /// for diagnostics.
  const Expr *addUniqueAligned(const ValueDecl *D, const Expr *NewDE);

  /// Register specified variable as loop control variable.
  void addLoopControlVariable(const ValueDecl *D, VarDecl *Capture);
  /// Check if the specified variable is a loop control variable for
  /// current region.
  /// \return The index of the loop control variable in the list of associated
  /// for-loops (from outer to inner).
  const LCDeclInfo isLoopControlVariable(const ValueDecl *D) const;
  /// Check if the specified variable is a loop control variable for
  /// parent region.
  /// \return The index of the loop control variable in the list of associated
  /// for-loops (from outer to inner).
  const LCDeclInfo isParentLoopControlVariable(const ValueDecl *D) const;
  /// Get the loop control variable for the I-th loop (or nullptr) in
  /// parent directive.
  const ValueDecl *getParentLoopControlVariable(unsigned I) const;

  /// Adds explicit data sharing attribute to the specified declaration.
  void addDSA(const ValueDecl *D, const Expr *E, OpenMPClauseKind A,
              DeclRefExpr *PrivateCopy = nullptr);

  /// Adds additional information for the reduction items with the reduction id
  /// represented as an operator.
  void addTaskgroupReductionData(const ValueDecl *D, SourceRange SR,
                                 BinaryOperatorKind BOK);
  /// Adds additional information for the reduction items with the reduction id
  /// represented as reduction identifier.
  void addTaskgroupReductionData(const ValueDecl *D, SourceRange SR,
                                 const Expr *ReductionRef);
  /// Returns the location and reduction operation from the innermost parent
  /// region for the given \p D.
  const DSAVarData
  getTopMostTaskgroupReductionData(const ValueDecl *D, SourceRange &SR,
                                   BinaryOperatorKind &BOK,
                                   Expr *&TaskgroupDescriptor) const;
  /// Returns the location and reduction operation from the innermost parent
  /// region for the given \p D.
  const DSAVarData
  getTopMostTaskgroupReductionData(const ValueDecl *D, SourceRange &SR,
                                   const Expr *&ReductionRef,
                                   Expr *&TaskgroupDescriptor) const;
  /// Return reduction reference expression for the current taskgroup.
  Expr *getTaskgroupReductionRef() const {
    assert(Stack.back().first.back().Directive == OMPD_taskgroup &&
           "taskgroup reference expression requested for non taskgroup "
           "directive.");
    return Stack.back().first.back().TaskgroupReductionRef;
  }
  /// Checks if the given \p VD declaration is actually a taskgroup reduction
  /// descriptor variable at the \p Level of OpenMP regions.
  bool isTaskgroupReductionRef(const ValueDecl *VD, unsigned Level) const {
    return Stack.back().first[Level].TaskgroupReductionRef &&
           cast<DeclRefExpr>(Stack.back().first[Level].TaskgroupReductionRef)
                   ->getDecl() == VD;
  }

  /// Returns data sharing attributes from top of the stack for the
  /// specified declaration.
  const DSAVarData getTopDSA(ValueDecl *D, bool FromParent);
  /// Returns data-sharing attributes for the specified declaration.
  const DSAVarData getImplicitDSA(ValueDecl *D, bool FromParent) const;
  /// Checks if the specified variables has data-sharing attributes which
  /// match specified \a CPred predicate in any directive which matches \a DPred
  /// predicate.
  const DSAVarData
  hasDSA(ValueDecl *D, const llvm::function_ref<bool(OpenMPClauseKind)> CPred,
         const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
         bool FromParent) const;
  /// Checks if the specified variables has data-sharing attributes which
  /// match specified \a CPred predicate in any innermost directive which
  /// matches \a DPred predicate.
  const DSAVarData
  hasInnermostDSA(ValueDecl *D,
                  const llvm::function_ref<bool(OpenMPClauseKind)> CPred,
                  const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
                  bool FromParent) const;
  /// Checks if the specified variables has explicit data-sharing
  /// attributes which match specified \a CPred predicate at the specified
  /// OpenMP region.
  bool hasExplicitDSA(const ValueDecl *D,
                      const llvm::function_ref<bool(OpenMPClauseKind)> CPred,
                      unsigned Level, bool NotLastprivate = false) const;

  /// Returns true if the directive at level \Level matches in the
  /// specified \a DPred predicate.
  bool hasExplicitDirective(
      const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
      unsigned Level) const;

  /// Finds a directive which matches specified \a DPred predicate.
  bool hasDirective(
      const llvm::function_ref<bool(
          OpenMPDirectiveKind, const DeclarationNameInfo &, SourceLocation)>
          DPred,
      bool FromParent) const;

  /// Returns currently analyzed directive.
  OpenMPDirectiveKind getCurrentDirective() const {
    return isStackEmpty() ? OMPD_unknown : Stack.back().first.back().Directive;
  }
  /// Returns directive kind at specified level.
  OpenMPDirectiveKind getDirective(unsigned Level) const {
    assert(!isStackEmpty() && "No directive at specified level.");
    return Stack.back().first[Level].Directive;
  }
  /// Returns parent directive.
  OpenMPDirectiveKind getParentDirective() const {
    if (isStackEmpty() || Stack.back().first.size() == 1)
      return OMPD_unknown;
    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());
    Stack.back().first.back().DefaultAttr = DSA_none;
    Stack.back().first.back().DefaultAttrLoc = Loc;
  }
  /// Set default data sharing attribute to shared.
  void setDefaultDSAShared(SourceLocation Loc) {
    assert(!isStackEmpty());
    Stack.back().first.back().DefaultAttr = DSA_shared;
    Stack.back().first.back().DefaultAttrLoc = Loc;
  }
  /// Set default data mapping attribute to 'tofrom:scalar'.
  void setDefaultDMAToFromScalar(SourceLocation Loc) {
    assert(!isStackEmpty());
    Stack.back().first.back().DefaultMapAttr = DMA_tofrom_scalar;
    Stack.back().first.back().DefaultMapAttrLoc = Loc;
  }

  DefaultDataSharingAttributes getDefaultDSA() const {
    return isStackEmpty() ? DSA_unspecified
                          : Stack.back().first.back().DefaultAttr;
  }
  SourceLocation getDefaultDSALocation() const {
    return isStackEmpty() ? SourceLocation()
                          : Stack.back().first.back().DefaultAttrLoc;
  }
  DefaultMapAttributes getDefaultDMA() const {
    return isStackEmpty() ? DMA_unspecified
                          : Stack.back().first.back().DefaultMapAttr;
  }
  DefaultMapAttributes getDefaultDMAAtLevel(unsigned Level) const {
    return Stack.back().first[Level].DefaultMapAttr;
  }
  SourceLocation getDefaultDMALocation() const {
    return isStackEmpty() ? SourceLocation()
                          : Stack.back().first.back().DefaultMapAttrLoc;
  }

  /// Checks if the specified variable is a threadprivate.
  bool isThreadPrivate(VarDecl *D) {
    const DSAVarData DVar = getTopDSA(D, false);
    return isOpenMPThreadPrivate(DVar.CKind);
  }

  /// Marks current region as ordered (it has an 'ordered' clause).
  void setOrderedRegion(bool IsOrdered, const Expr *Param,
                        OMPOrderedClause *Clause) {
    assert(!isStackEmpty());
    if (IsOrdered)
      Stack.back().first.back().OrderedRegion.emplace(Param, Clause);
    else
      Stack.back().first.back().OrderedRegion.reset();
  }
  /// Returns true, if region is ordered (has associated 'ordered' clause),
  /// false - otherwise.
  bool isOrderedRegion() const {
    if (isStackEmpty())
      return false;
    return Stack.back().first.rbegin()->OrderedRegion.hasValue();
  }
  /// Returns optional parameter for the ordered region.
  std::pair<const Expr *, OMPOrderedClause *> getOrderedRegionParam() const {
    if (isStackEmpty() ||
        !Stack.back().first.rbegin()->OrderedRegion.hasValue())
      return std::make_pair(nullptr, nullptr);
    return Stack.back().first.rbegin()->OrderedRegion.getValue();
  }
  /// Returns true, if parent region is ordered (has associated
  /// 'ordered' clause), false - otherwise.
  bool isParentOrderedRegion() const {
    if (isStackEmpty() || Stack.back().first.size() == 1)
      return false;
    return std::next(Stack.back().first.rbegin())->OrderedRegion.hasValue();
  }
  /// Returns optional parameter for the ordered region.
  std::pair<const Expr *, OMPOrderedClause *>
  getParentOrderedRegionParam() const {
    if (isStackEmpty() || Stack.back().first.size() == 1 ||
        !std::next(Stack.back().first.rbegin())->OrderedRegion.hasValue())
      return std::make_pair(nullptr, nullptr);
    return std::next(Stack.back().first.rbegin())->OrderedRegion.getValue();
  }
  /// Marks current region as nowait (it has a 'nowait' clause).
  void setNowaitRegion(bool IsNowait = true) {
    assert(!isStackEmpty());
    Stack.back().first.back().NowaitRegion = IsNowait;
  }
  /// Returns true, if parent region is nowait (has associated
  /// 'nowait' clause), false - otherwise.
  bool isParentNowaitRegion() const {
    if (isStackEmpty() || Stack.back().first.size() == 1)
      return false;
    return std::next(Stack.back().first.rbegin())->NowaitRegion;
  }
  /// Marks parent region as cancel region.
  void setParentCancelRegion(bool Cancel = true) {
    if (!isStackEmpty() && Stack.back().first.size() > 1) {
      auto &StackElemRef = *std::next(Stack.back().first.rbegin());
      StackElemRef.CancelRegion |= StackElemRef.CancelRegion || Cancel;
    }
  }
  /// Return true if current region has inner cancel construct.
  bool isCancelRegion() const {
    return isStackEmpty() ? false : Stack.back().first.back().CancelRegion;
  }

  /// Set collapse value for the region.
  void setAssociatedLoops(unsigned Val) {
    assert(!isStackEmpty());
    Stack.back().first.back().AssociatedLoops = Val;
  }
  /// Return collapse value for region.
  unsigned getAssociatedLoops() const {
    return isStackEmpty() ? 0 : Stack.back().first.back().AssociatedLoops;
  }

  /// Marks current target region as one with closely nested teams
  /// region.
  void setParentTeamsRegionLoc(SourceLocation TeamsRegionLoc) {
    if (!isStackEmpty() && Stack.back().first.size() > 1) {
      std::next(Stack.back().first.rbegin())->InnerTeamsRegionLoc =
          TeamsRegionLoc;
    }
  }
  /// Returns true, if current region has closely nested teams region.
  bool hasInnerTeamsRegion() const {
    return getInnerTeamsRegionLoc().isValid();
  }
  /// Returns location of the nested teams region (if any).
  SourceLocation getInnerTeamsRegionLoc() const {
    return isStackEmpty() ? SourceLocation()
                          : Stack.back().first.back().InnerTeamsRegionLoc;
  }

  Scope *getCurScope() const {
    return isStackEmpty() ? nullptr : Stack.back().first.back().CurScope;
  }
  SourceLocation getConstructLoc() const {
    return isStackEmpty() ? SourceLocation()
                          : Stack.back().first.back().ConstructLoc;
  }

  /// Do the check specified in \a Check to all component lists and return true
  /// if any issue is found.
  bool checkMappableExprComponentListsForDecl(
      const ValueDecl *VD, bool CurrentRegionOnly,
      const llvm::function_ref<
          bool(OMPClauseMappableExprCommon::MappableExprComponentListRef,
               OpenMPClauseKind)>
          Check) const {
    if (isStackEmpty())
      return false;
    auto SI = Stack.back().first.rbegin();
    auto SE = Stack.back().first.rend();

    if (SI == SE)
      return false;

    if (CurrentRegionOnly)
      SE = std::next(SI);
    else
      std::advance(SI, 1);

    for (; SI != SE; ++SI) {
      auto MI = SI->MappedExprComponents.find(VD);
      if (MI != SI->MappedExprComponents.end())
        for (OMPClauseMappableExprCommon::MappableExprComponentListRef L :
             MI->second.Components)
          if (Check(L, MI->second.Kind))
            return true;
    }
    return false;
  }

  /// Do the check specified in \a Check to all component lists at a given level
  /// and return true if any issue is found.
  bool checkMappableExprComponentListsForDeclAtLevel(
      const ValueDecl *VD, unsigned Level,
      const llvm::function_ref<
          bool(OMPClauseMappableExprCommon::MappableExprComponentListRef,
               OpenMPClauseKind)>
          Check) const {
    if (isStackEmpty())
      return false;

    auto StartI = Stack.back().first.begin();
    auto EndI = Stack.back().first.end();
    if (std::distance(StartI, EndI) <= (int)Level)
      return false;
    std::advance(StartI, Level);

    auto MI = StartI->MappedExprComponents.find(VD);
    if (MI != StartI->MappedExprComponents.end())
      for (OMPClauseMappableExprCommon::MappableExprComponentListRef L :
           MI->second.Components)
        if (Check(L, MI->second.Kind))
          return true;
    return false;
  }

  /// Create a new mappable expression component list associated with a given
  /// declaration and initialize it with the provided list of components.
  void addMappableExpressionComponents(
      const ValueDecl *VD,
      OMPClauseMappableExprCommon::MappableExprComponentListRef Components,
      OpenMPClauseKind WhereFoundClauseKind) {
    assert(!isStackEmpty() &&
           "Not expecting to retrieve components from a empty stack!");
    MappedExprComponentTy &MEC =
        Stack.back().first.back().MappedExprComponents[VD];
    // Create new entry and append the new components there.
    MEC.Components.resize(MEC.Components.size() + 1);
    MEC.Components.back().append(Components.begin(), Components.end());
    MEC.Kind = WhereFoundClauseKind;
  }

  unsigned getNestingLevel() const {
    assert(!isStackEmpty());
    return Stack.back().first.size() - 1;
  }
  void addDoacrossDependClause(OMPDependClause *C,
                               const OperatorOffsetTy &OpsOffs) {
    assert(!isStackEmpty() && Stack.back().first.size() > 1);
    SharingMapTy &StackElem = *std::next(Stack.back().first.rbegin());
    assert(isOpenMPWorksharingDirective(StackElem.Directive));
    StackElem.DoacrossDepends.try_emplace(C, OpsOffs);
  }
  llvm::iterator_range<DoacrossDependMapTy::const_iterator>
  getDoacrossDependClauses() const {
    assert(!isStackEmpty());
    const SharingMapTy &StackElem = Stack.back().first.back();
    if (isOpenMPWorksharingDirective(StackElem.Directive)) {
      const DoacrossDependMapTy &Ref = StackElem.DoacrossDepends;
      return llvm::make_range(Ref.begin(), Ref.end());
    }
    return llvm::make_range(StackElem.DoacrossDepends.end(),
                            StackElem.DoacrossDepends.end());
  }
};
bool isParallelOrTaskRegion(OpenMPDirectiveKind DKind) {
  return isOpenMPParallelDirective(DKind) || isOpenMPTaskingDirective(DKind) ||
         isOpenMPTeamsDirective(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 *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
    E = MTE->GetTemporaryExpr();

  while (const auto *Binder = dyn_cast<CXXBindTemporaryExpr>(E))
    E = Binder->getSubExpr();

  if (const auto *ICE = dyn_cast<ImplicitCastExpr>(E))
    E = ICE->getSubExprAsWritten();
  return E->IgnoreParens();
}

static Expr *getExprAsWritten(Expr *E) {
  return const_cast<Expr *>(getExprAsWritten(const_cast<const Expr *>(E)));
}

static const ValueDecl *getCanonicalDecl(const ValueDecl *D) {
  if (const auto *CED = dyn_cast<OMPCapturedExprDecl>(D))
    if (const auto *ME = dyn_cast<MemberExpr>(getExprAsWritten(CED->getInit())))
      D = ME->getMemberDecl();
  const auto *VD = dyn_cast<VarDecl>(D);
  const auto *FD = dyn_cast<FieldDecl>(D);
  if (VD != nullptr) {
    VD = VD->getCanonicalDecl();
    D = VD;
  } else {
    assert(FD);
    FD = FD->getCanonicalDecl();
    D = FD;
  }
  return D;
}

static ValueDecl *getCanonicalDecl(ValueDecl *D) {
  return const_cast<ValueDecl *>(
      getCanonicalDecl(const_cast<const ValueDecl *>(D)));
}

DSAStackTy::DSAVarData DSAStackTy::getDSA(iterator &Iter,
                                          ValueDecl *D) const {
  D = getCanonicalDecl(D);
  auto *VD = dyn_cast<VarDecl>(D);
  const auto *FD = dyn_cast<FieldDecl>(D);
  DSAVarData DVar;
  if (isStackEmpty() || Iter == Stack.back().first.rend()) {
    // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
    // in a region but not in construct]
    //  File-scope or namespace-scope variables referenced in called routines
    //  in the region are shared unless they appear in a threadprivate
    //  directive.
    if (VD && !VD->isFunctionOrMethodVarDecl() && !isa<ParmVarDecl>(VD))
      DVar.CKind = OMPC_shared;

    // OpenMP [2.9.1.2, Data-sharing Attribute Rules for Variables Referenced
    // in a region but not in construct]
    //  Variables with static storage duration that are declared in called
    //  routines in the region are shared.
    if (VD && VD->hasGlobalStorage())
      DVar.CKind = OMPC_shared;

    // Non-static data members are shared by default.
    if (FD)
      DVar.CKind = OMPC_shared;

    return DVar;
  }

  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.1]
  // Variables with automatic storage duration that are declared in a scope
  // inside the construct are private.
  if (VD && isOpenMPLocal(VD, Iter) && VD->isLocalVarDecl() &&
      (VD->getStorageClass() == SC_Auto || VD->getStorageClass() == SC_None)) {
    DVar.CKind = OMPC_private;
    return DVar;
  }

  DVar.DKind = Iter->Directive;
  // Explicitly specified attributes and local variables with predetermined
  // attributes.
  if (Iter->SharingMap.count(D)) {
    const DSAInfo &Data = Iter->SharingMap.lookup(D);
    DVar.RefExpr = Data.RefExpr.getPointer();
    DVar.PrivateCopy = Data.PrivateCopy;
    DVar.CKind = Data.Attributes;
    DVar.ImplicitDSALoc = Iter->DefaultAttrLoc;
    return DVar;
  }

  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, implicitly determined, p.1]
  //  In a parallel or task construct, the data-sharing attributes of these
  //  variables are determined by the default clause, if present.
  switch (Iter->DefaultAttr) {
  case DSA_shared:
    DVar.CKind = OMPC_shared;
    DVar.ImplicitDSALoc = Iter->DefaultAttrLoc;
    return DVar;
  case DSA_none:
    return DVar;
  case DSA_unspecified:
    // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
    // in a Construct, implicitly determined, p.2]
    //  In a parallel construct, if no default clause is present, these
    //  variables are shared.
    DVar.ImplicitDSALoc = Iter->DefaultAttrLoc;
    if (isOpenMPParallelDirective(DVar.DKind) ||
        isOpenMPTeamsDirective(DVar.DKind)) {
      DVar.CKind = OMPC_shared;
      return DVar;
    }

    // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
    // in a Construct, implicitly determined, p.4]
    //  In a task construct, if no default clause is present, a variable that in
    //  the enclosing context is determined to be shared by all implicit tasks
    //  bound to the current team is shared.
    if (isOpenMPTaskingDirective(DVar.DKind)) {
      DSAVarData DVarTemp;
      iterator I = Iter, E = Stack.back().first.rend();
      do {
        ++I;
        // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables
        // Referenced in a Construct, implicitly determined, p.6]
        //  In a task construct, if no default clause is present, a variable
        //  whose data-sharing attribute is not determined by the rules above is
        //  firstprivate.
        DVarTemp = getDSA(I, D);
        if (DVarTemp.CKind != OMPC_shared) {
          DVar.RefExpr = nullptr;
          DVar.CKind = OMPC_firstprivate;
          return DVar;
        }
      } while (I != E && !isParallelOrTaskRegion(I->Directive));
      DVar.CKind =
          (DVarTemp.CKind == OMPC_unknown) ? OMPC_firstprivate : OMPC_shared;
      return DVar;
    }
  }
  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, implicitly determined, p.3]
  //  For constructs other than task, if no default clause is present, these
  //  variables inherit their data-sharing attributes from the enclosing
  //  context.
  return getDSA(++Iter, D);
}

const Expr *DSAStackTy::addUniqueAligned(const ValueDecl *D,
                                         const Expr *NewDE) {
  assert(!isStackEmpty() && "Data sharing attributes stack is empty");
  D = getCanonicalDecl(D);
  SharingMapTy &StackElem = Stack.back().first.back();
  auto It = StackElem.AlignedMap.find(D);
  if (It == StackElem.AlignedMap.end()) {
    assert(NewDE && "Unexpected nullptr expr to be added into aligned map");
    StackElem.AlignedMap[D] = NewDE;
    return nullptr;
  }
  assert(It->second && "Unexpected nullptr expr in the aligned map");
  return It->second;
}

void DSAStackTy::addLoopControlVariable(const ValueDecl *D, VarDecl *Capture) {
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty");
  D = getCanonicalDecl(D);
  SharingMapTy &StackElem = Stack.back().first.back();
  StackElem.LCVMap.try_emplace(
      D, LCDeclInfo(StackElem.LCVMap.size() + 1, Capture));
}

const DSAStackTy::LCDeclInfo
DSAStackTy::isLoopControlVariable(const ValueDecl *D) const {
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty");
  D = getCanonicalDecl(D);
  const SharingMapTy &StackElem = Stack.back().first.back();
  auto It = StackElem.LCVMap.find(D);
  if (It != StackElem.LCVMap.end())
    return It->second;
  return {0, nullptr};
}

const DSAStackTy::LCDeclInfo
DSAStackTy::isParentLoopControlVariable(const ValueDecl *D) const {
  assert(!isStackEmpty() && Stack.back().first.size() > 1 &&
         "Data-sharing attributes stack is empty");
  D = getCanonicalDecl(D);
  const SharingMapTy &StackElem = *std::next(Stack.back().first.rbegin());
  auto It = StackElem.LCVMap.find(D);
  if (It != StackElem.LCVMap.end())
    return It->second;
  return {0, nullptr};
}

const ValueDecl *DSAStackTy::getParentLoopControlVariable(unsigned I) const {
  assert(!isStackEmpty() && Stack.back().first.size() > 1 &&
         "Data-sharing attributes stack is empty");
  const SharingMapTy &StackElem = *std::next(Stack.back().first.rbegin());
  if (StackElem.LCVMap.size() < I)
    return nullptr;
  for (const auto &Pair : StackElem.LCVMap)
    if (Pair.second.first == I)
      return Pair.first;
  return nullptr;
}

void DSAStackTy::addDSA(const ValueDecl *D, const Expr *E, OpenMPClauseKind A,
                        DeclRefExpr *PrivateCopy) {
  D = getCanonicalDecl(D);
  if (A == OMPC_threadprivate) {
    DSAInfo &Data = Threadprivates[D];
    Data.Attributes = A;
    Data.RefExpr.setPointer(E);
    Data.PrivateCopy = nullptr;
  } else {
    assert(!isStackEmpty() && "Data-sharing attributes stack is empty");
    DSAInfo &Data = Stack.back().first.back().SharingMap[D];
    assert(Data.Attributes == OMPC_unknown || (A == Data.Attributes) ||
           (A == OMPC_firstprivate && Data.Attributes == OMPC_lastprivate) ||
           (A == OMPC_lastprivate && Data.Attributes == OMPC_firstprivate) ||
           (isLoopControlVariable(D).first && A == OMPC_private));
    if (A == OMPC_lastprivate && Data.Attributes == OMPC_firstprivate) {
      Data.RefExpr.setInt(/*IntVal=*/true);
      return;
    }
    const bool IsLastprivate =
        A == OMPC_lastprivate || Data.Attributes == OMPC_lastprivate;
    Data.Attributes = A;
    Data.RefExpr.setPointerAndInt(E, IsLastprivate);
    Data.PrivateCopy = PrivateCopy;
    if (PrivateCopy) {
      DSAInfo &Data =
          Stack.back().first.back().SharingMap[PrivateCopy->getDecl()];
      Data.Attributes = A;
      Data.RefExpr.setPointerAndInt(PrivateCopy, IsLastprivate);
      Data.PrivateCopy = nullptr;
    }
  }
}

/// Build a variable declaration for OpenMP loop iteration variable.
static VarDecl *buildVarDecl(Sema &SemaRef, SourceLocation Loc, QualType Type,
                             StringRef Name, const AttrVec *Attrs = nullptr,
                             DeclRefExpr *OrigRef = nullptr) {
  DeclContext *DC = SemaRef.CurContext;
  IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
  TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc);
  auto *Decl =
      VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, TInfo, SC_None);
  if (Attrs) {
    for (specific_attr_iterator<AlignedAttr> I(Attrs->begin()), E(Attrs->end());
         I != E; ++I)
      Decl->addAttr(*I);
  }
  Decl->setImplicit();
  if (OrigRef) {
    Decl->addAttr(
        OMPReferencedVarAttr::CreateImplicit(SemaRef.Context, OrigRef));
  }
  return Decl;
}

static DeclRefExpr *buildDeclRefExpr(Sema &S, VarDecl *D, QualType Ty,
                                     SourceLocation Loc,
                                     bool RefersToCapture = false) {
  D->setReferenced();
  D->markUsed(S.Context);
  return DeclRefExpr::Create(S.getASTContext(), NestedNameSpecifierLoc(),
                             SourceLocation(), D, RefersToCapture, Loc, Ty,
                             VK_LValue);
}

void DSAStackTy::addTaskgroupReductionData(const ValueDecl *D, SourceRange SR,
                                           BinaryOperatorKind BOK) {
  D = getCanonicalDecl(D);
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty");
  assert(
      Stack.back().first.back().SharingMap[D].Attributes == OMPC_reduction &&
      "Additional reduction info may be specified only for reduction items.");
  ReductionData &ReductionData = Stack.back().first.back().ReductionMap[D];
  assert(ReductionData.ReductionRange.isInvalid() &&
         Stack.back().first.back().Directive == OMPD_taskgroup &&
         "Additional reduction info may be specified only once for reduction "
         "items.");
  ReductionData.set(BOK, SR);
  Expr *&TaskgroupReductionRef =
      Stack.back().first.back().TaskgroupReductionRef;
  if (!TaskgroupReductionRef) {
    VarDecl *VD = buildVarDecl(SemaRef, SR.getBegin(),
                               SemaRef.Context.VoidPtrTy, ".task_red.");
    TaskgroupReductionRef =
        buildDeclRefExpr(SemaRef, VD, SemaRef.Context.VoidPtrTy, SR.getBegin());
  }
}

void DSAStackTy::addTaskgroupReductionData(const ValueDecl *D, SourceRange SR,
                                           const Expr *ReductionRef) {
  D = getCanonicalDecl(D);
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty");
  assert(
      Stack.back().first.back().SharingMap[D].Attributes == OMPC_reduction &&
      "Additional reduction info may be specified only for reduction items.");
  ReductionData &ReductionData = Stack.back().first.back().ReductionMap[D];
  assert(ReductionData.ReductionRange.isInvalid() &&
         Stack.back().first.back().Directive == OMPD_taskgroup &&
         "Additional reduction info may be specified only once for reduction "
         "items.");
  ReductionData.set(ReductionRef, SR);
  Expr *&TaskgroupReductionRef =
      Stack.back().first.back().TaskgroupReductionRef;
  if (!TaskgroupReductionRef) {
    VarDecl *VD = buildVarDecl(SemaRef, SR.getBegin(),
                               SemaRef.Context.VoidPtrTy, ".task_red.");
    TaskgroupReductionRef =
        buildDeclRefExpr(SemaRef, VD, SemaRef.Context.VoidPtrTy, SR.getBegin());
  }
}

const DSAStackTy::DSAVarData DSAStackTy::getTopMostTaskgroupReductionData(
    const ValueDecl *D, SourceRange &SR, BinaryOperatorKind &BOK,
    Expr *&TaskgroupDescriptor) const {
  D = getCanonicalDecl(D);
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty.");
  if (Stack.back().first.empty())
      return DSAVarData();
  for (iterator I = std::next(Stack.back().first.rbegin(), 1),
                E = Stack.back().first.rend();
       I != E; std::advance(I, 1)) {
    const DSAInfo &Data = I->SharingMap.lookup(D);
    if (Data.Attributes != OMPC_reduction || I->Directive != OMPD_taskgroup)
      continue;
    const ReductionData &ReductionData = I->ReductionMap.lookup(D);
    if (!ReductionData.ReductionOp ||
        ReductionData.ReductionOp.is<const Expr *>())
      return DSAVarData();
    SR = ReductionData.ReductionRange;
    BOK = ReductionData.ReductionOp.get<ReductionData::BOKPtrType>();
    assert(I->TaskgroupReductionRef && "taskgroup reduction reference "
                                       "expression for the descriptor is not "
                                       "set.");
    TaskgroupDescriptor = I->TaskgroupReductionRef;
    return DSAVarData(OMPD_taskgroup, OMPC_reduction, Data.RefExpr.getPointer(),
                      Data.PrivateCopy, I->DefaultAttrLoc);
  }
  return DSAVarData();
}

const DSAStackTy::DSAVarData DSAStackTy::getTopMostTaskgroupReductionData(
    const ValueDecl *D, SourceRange &SR, const Expr *&ReductionRef,
    Expr *&TaskgroupDescriptor) const {
  D = getCanonicalDecl(D);
  assert(!isStackEmpty() && "Data-sharing attributes stack is empty.");
  if (Stack.back().first.empty())
      return DSAVarData();
  for (iterator I = std::next(Stack.back().first.rbegin(), 1),
                E = Stack.back().first.rend();
       I != E; std::advance(I, 1)) {
    const DSAInfo &Data = I->SharingMap.lookup(D);
    if (Data.Attributes != OMPC_reduction || I->Directive != OMPD_taskgroup)
      continue;
    const ReductionData &ReductionData = I->ReductionMap.lookup(D);
    if (!ReductionData.ReductionOp ||
        !ReductionData.ReductionOp.is<const Expr *>())
      return DSAVarData();
    SR = ReductionData.ReductionRange;
    ReductionRef = ReductionData.ReductionOp.get<const Expr *>();
    assert(I->TaskgroupReductionRef && "taskgroup reduction reference "
                                       "expression for the descriptor is not "
                                       "set.");
    TaskgroupDescriptor = I->TaskgroupReductionRef;
    return DSAVarData(OMPD_taskgroup, OMPC_reduction, Data.RefExpr.getPointer(),
                      Data.PrivateCopy, I->DefaultAttrLoc);
  }
  return DSAVarData();
}

bool DSAStackTy::isOpenMPLocal(VarDecl *D, iterator Iter) const {
  D = D->getCanonicalDecl();
  if (!isStackEmpty()) {
    iterator I = Iter, E = Stack.back().first.rend();
    Scope *TopScope = nullptr;
    while (I != E && !isParallelOrTaskRegion(I->Directive) &&
           !isOpenMPTargetExecutionDirective(I->Directive))
      ++I;
    if (I == E)
      return false;
    TopScope = I->CurScope ? I->CurScope->getParent() : nullptr;
    Scope *CurScope = getCurScope();
    while (CurScope != TopScope && !CurScope->isDeclScope(D))
      CurScope = CurScope->getParent();
    return CurScope != TopScope;
  }
  return false;
}

const DSAStackTy::DSAVarData DSAStackTy::getTopDSA(ValueDecl *D,
                                                   bool FromParent) {
  D = getCanonicalDecl(D);
  DSAVarData DVar;

  auto *VD = dyn_cast<VarDecl>(D);
  auto TI = Threadprivates.find(D);
  if (TI != Threadprivates.end()) {
    DVar.RefExpr = TI->getSecond().RefExpr.getPointer();
    DVar.CKind = OMPC_threadprivate;
    return DVar;
  }
  if (VD && VD->hasAttr<OMPThreadPrivateDeclAttr>()) {
    DVar.RefExpr = buildDeclRefExpr(
        SemaRef, VD, D->getType().getNonReferenceType(),
        VD->getAttr<OMPThreadPrivateDeclAttr>()->getLocation());
    DVar.CKind = OMPC_threadprivate;
    addDSA(D, DVar.RefExpr, OMPC_threadprivate);
    return DVar;
  }
  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.1]
  //  Variables appearing in threadprivate directives are threadprivate.
  if ((VD && VD->getTLSKind() != VarDecl::TLS_None &&
       !(VD->hasAttr<OMPThreadPrivateDeclAttr>() &&
         SemaRef.getLangOpts().OpenMPUseTLS &&
         SemaRef.getASTContext().getTargetInfo().isTLSSupported())) ||
      (VD && VD->getStorageClass() == SC_Register &&
       VD->hasAttr<AsmLabelAttr>() && !VD->isLocalVarDecl())) {
    DVar.RefExpr = buildDeclRefExpr(
        SemaRef, VD, D->getType().getNonReferenceType(), D->getLocation());
    DVar.CKind = OMPC_threadprivate;
    addDSA(D, DVar.RefExpr, OMPC_threadprivate);
    return DVar;
  }
  if (SemaRef.getLangOpts().OpenMPCUDAMode && VD &&
      VD->isLocalVarDeclOrParm() && !isStackEmpty() &&
      !isLoopControlVariable(D).first) {
    iterator IterTarget =
        std::find_if(Stack.back().first.rbegin(), Stack.back().first.rend(),
                     [](const SharingMapTy &Data) {
                       return isOpenMPTargetExecutionDirective(Data.Directive);
                     });
    if (IterTarget != Stack.back().first.rend()) {
      iterator ParentIterTarget = std::next(IterTarget, 1);
      for (iterator Iter = Stack.back().first.rbegin();
           Iter != ParentIterTarget; std::advance(Iter, 1)) {
        if (isOpenMPLocal(VD, Iter)) {
          DVar.RefExpr =
              buildDeclRefExpr(SemaRef, VD, D->getType().getNonReferenceType(),
                               D->getLocation());
          DVar.CKind = OMPC_threadprivate;
          return DVar;
        }
      }
      if (!isClauseParsingMode() || IterTarget != Stack.back().first.rbegin()) {
        auto DSAIter = IterTarget->SharingMap.find(D);
        if (DSAIter != IterTarget->SharingMap.end() &&
            isOpenMPPrivate(DSAIter->getSecond().Attributes)) {
          DVar.RefExpr = DSAIter->getSecond().RefExpr.getPointer();
          DVar.CKind = OMPC_threadprivate;
          return DVar;
        }
        iterator End = Stack.back().first.rend();
        if (!SemaRef.isOpenMPCapturedByRef(
                D, std::distance(ParentIterTarget, End))) {
          DVar.RefExpr =
              buildDeclRefExpr(SemaRef, VD, D->getType().getNonReferenceType(),
                               IterTarget->ConstructLoc);
          DVar.CKind = OMPC_threadprivate;
          return DVar;
        }
      }
    }
  }

  if (isStackEmpty())
    // Not in OpenMP execution region and top scope was already checked.
    return DVar;

  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.4]
  //  Static data members are shared.
  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.7]
  //  Variables with static storage duration that are declared in a scope
  //  inside the construct are shared.
  auto &&MatchesAlways = [](OpenMPDirectiveKind) { return true; };
  if (VD && VD->isStaticDataMember()) {
    DSAVarData DVarTemp = hasDSA(D, isOpenMPPrivate, MatchesAlways, FromParent);
    if (DVarTemp.CKind != OMPC_unknown && DVarTemp.RefExpr)
      return DVar;

    DVar.CKind = OMPC_shared;
    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;

    DVar.CKind = OMPC_shared;
    return DVar;
  }

  // Explicitly specified attributes and local variables with predetermined
  // attributes.
  iterator I = Stack.back().first.rbegin();
  iterator EndI = Stack.back().first.rend();
  if (FromParent && I != EndI)
    std::advance(I, 1);
  auto It = I->SharingMap.find(D);
  if (It != I->SharingMap.end()) {
    const DSAInfo &Data = It->getSecond();
    DVar.RefExpr = Data.RefExpr.getPointer();
    DVar.PrivateCopy = Data.PrivateCopy;
    DVar.CKind = Data.Attributes;
    DVar.ImplicitDSALoc = I->DefaultAttrLoc;
    DVar.DKind = I->Directive;
  }

  return DVar;
}

const DSAStackTy::DSAVarData DSAStackTy::getImplicitDSA(ValueDecl *D,
                                                        bool FromParent) const {
  if (isStackEmpty()) {
    iterator I;
    return getDSA(I, D);
  }
  D = getCanonicalDecl(D);
  iterator StartI = Stack.back().first.rbegin();
  iterator EndI = Stack.back().first.rend();
  if (FromParent && StartI != EndI)
    std::advance(StartI, 1);
  return getDSA(StartI, D);
}

const DSAStackTy::DSAVarData
DSAStackTy::hasDSA(ValueDecl *D,
                   const llvm::function_ref<bool(OpenMPClauseKind)> CPred,
                   const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
                   bool FromParent) const {
  if (isStackEmpty())
    return {};
  D = getCanonicalDecl(D);
  iterator I = Stack.back().first.rbegin();
  iterator EndI = Stack.back().first.rend();
  if (FromParent && I != EndI)
    std::advance(I, 1);
  for (; I != EndI; std::advance(I, 1)) {
    if (!DPred(I->Directive) && !isParallelOrTaskRegion(I->Directive))
      continue;
    iterator NewI = I;
    DSAVarData DVar = getDSA(NewI, D);
    if (I == NewI && CPred(DVar.CKind))
      return DVar;
  }
  return {};
}

const DSAStackTy::DSAVarData DSAStackTy::hasInnermostDSA(
    ValueDecl *D, const llvm::function_ref<bool(OpenMPClauseKind)> CPred,
    const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
    bool FromParent) const {
  if (isStackEmpty())
    return {};
  D = getCanonicalDecl(D);
  iterator StartI = Stack.back().first.rbegin();
  iterator EndI = Stack.back().first.rend();
  if (FromParent && StartI != EndI)
    std::advance(StartI, 1);
  if (StartI == EndI || !DPred(StartI->Directive))
    return {};
  iterator NewI = StartI;
  DSAVarData DVar = getDSA(NewI, D);
  return (NewI == StartI && CPred(DVar.CKind)) ? DVar : DSAVarData();
}

bool DSAStackTy::hasExplicitDSA(
    const ValueDecl *D, const llvm::function_ref<bool(OpenMPClauseKind)> CPred,
    unsigned Level, bool NotLastprivate) const {
  if (isStackEmpty())
    return false;
  D = getCanonicalDecl(D);
  auto StartI = Stack.back().first.begin();
  auto EndI = Stack.back().first.end();
  if (std::distance(StartI, EndI) <= (int)Level)
    return false;
  std::advance(StartI, Level);
  auto I = StartI->SharingMap.find(D);
  return (I != StartI->SharingMap.end()) &&
         I->getSecond().RefExpr.getPointer() &&
         CPred(I->getSecond().Attributes) &&
         (!NotLastprivate || !I->getSecond().RefExpr.getInt());
}

bool DSAStackTy::hasExplicitDirective(
    const llvm::function_ref<bool(OpenMPDirectiveKind)> DPred,
    unsigned Level) const {
  if (isStackEmpty())
    return false;
  auto StartI = Stack.back().first.begin();
  auto EndI = Stack.back().first.end();
  if (std::distance(StartI, EndI) <= (int)Level)
    return false;
  std::advance(StartI, Level);
  return DPred(StartI->Directive);
}

bool DSAStackTy::hasDirective(
    const llvm::function_ref<bool(OpenMPDirectiveKind,
                                  const DeclarationNameInfo &, SourceLocation)>
        DPred,
    bool FromParent) const {
  // We look only in the enclosing region.
  if (isStackEmpty())
    return false;
  auto StartI = std::next(Stack.back().first.rbegin());
  auto EndI = Stack.back().first.rend();
  if (FromParent && StartI != EndI)
    StartI = std::next(StartI);
  for (auto I = StartI, EE = EndI; I != EE; ++I) {
    if (DPred(I->Directive, I->DirectiveName, I->ConstructLoc))
      return true;
  }
  return false;
}

void Sema::InitDataSharingAttributesStack() {
  VarDataSharingAttributesStack = new DSAStackTy(*this);
}

#define DSAStack static_cast<DSAStackTy *>(VarDataSharingAttributesStack)

void Sema::pushOpenMPFunctionRegion() {
  DSAStack->pushFunction();
}

void Sema::popOpenMPFunctionRegion(const FunctionScopeInfo *OldFSI) {
  DSAStack->popFunction(OldFSI);
}

bool Sema::isOpenMPCapturedByRef(const ValueDecl *D, unsigned Level) const {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");

  ASTContext &Ctx = getASTContext();
  bool IsByRef = true;

  // Find the directive that is associated with the provided scope.
  D = cast<ValueDecl>(D->getCanonicalDecl());
  QualType Ty = D->getType();

  if (DSAStack->hasExplicitDirective(isOpenMPTargetExecutionDirective, Level)) {
    // This table summarizes how a given variable should be passed to the device
    // given its type and the clauses where it appears. This table is based on
    // the description in OpenMP 4.5 [2.10.4, target Construct] and
    // OpenMP 4.5 [2.15.5, Data-mapping Attribute Rules and Clauses].
    //
    // =========================================================================
    // | type |  defaultmap   | pvt | first | is_device_ptr |    map   | res.  |
    // |      |(tofrom:scalar)|     |  pvt  |               |          |       |
    // =========================================================================
    // | scl  |               |     |       |       -       |          | bycopy|
    // | scl  |               |  -  |   x   |       -       |     -    | bycopy|
    // | scl  |               |  x  |   -   |       -       |     -    | null  |
    // | scl  |       x       |     |       |       -       |          | byref |
    // | scl  |       x       |  -  |   x   |       -       |     -    | bycopy|
    // | scl  |       x       |  x  |   -   |       -       |     -    | null  |
    // | scl  |               |  -  |   -   |       -       |     x    | byref |
    // | scl  |       x       |  -  |   -   |       -       |     x    | byref |
    //
    // | agg  |      n.a.     |     |       |       -       |          | byref |
    // | agg  |      n.a.     |  -  |   x   |       -       |     -    | byref |
    // | agg  |      n.a.     |  x  |   -   |       -       |     -    | null  |
    // | agg  |      n.a.     |  -  |   -   |       -       |     x    | byref |
    // | agg  |      n.a.     |  -  |   -   |       -       |    x[]   | byref |
    //
    // | ptr  |      n.a.     |     |       |       -       |          | bycopy|
    // | ptr  |      n.a.     |  -  |   x   |       -       |     -    | bycopy|
    // | ptr  |      n.a.     |  x  |   -   |       -       |     -    | null  |
    // | ptr  |      n.a.     |  -  |   -   |       -       |     x    | byref |
    // | ptr  |      n.a.     |  -  |   -   |       -       |    x[]   | bycopy|
    // | ptr  |      n.a.     |  -  |   -   |       x       |          | bycopy|
    // | ptr  |      n.a.     |  -  |   -   |       x       |     x    | bycopy|
    // | ptr  |      n.a.     |  -  |   -   |       x       |    x[]   | bycopy|
    // =========================================================================
    // Legend:
    //  scl - scalar
    //  ptr - pointer
    //  agg - aggregate
    //  x - applies
    //  - - invalid in this combination
    //  [] - mapped with an array section
    //  byref - should be mapped by reference
    //  byval - should be mapped by value
    //  null - initialize a local variable to null on the device
    //
    // Observations:
    //  - All scalar declarations that show up in a map clause have to be passed
    //    by reference, because they may have been mapped in the enclosing data
    //    environment.
    //  - If the scalar value does not fit the size of uintptr, it has to be
    //    passed by reference, regardless the result in the table above.
    //  - For pointers mapped by value that have either an implicit map or an
    //    array section, the runtime library may pass the NULL value to the
    //    device instead of the value passed to it by the compiler.

    if (Ty->isReferenceType())
      Ty = Ty->castAs<ReferenceType>()->getPointeeType();

    // Locate map clauses and see if the variable being captured is referred to
    // in any of those clauses. Here we only care about variables, not fields,
    // because fields are part of aggregates.
    bool IsVariableUsedInMapClause = false;
    bool IsVariableAssociatedWithSection = false;

    DSAStack->checkMappableExprComponentListsForDeclAtLevel(
        D, Level,
        [&IsVariableUsedInMapClause, &IsVariableAssociatedWithSection, D](
            OMPClauseMappableExprCommon::MappableExprComponentListRef
                MapExprComponents,
            OpenMPClauseKind WhereFoundClauseKind) {
          // Only the map clause information influences how a variable is
          // captured. E.g. is_device_ptr does not require changing the default
          // behavior.
          if (WhereFoundClauseKind != OMPC_map)
            return false;

          auto EI = MapExprComponents.rbegin();
          auto EE = MapExprComponents.rend();

          assert(EI != EE && "Invalid map expression!");

          if (isa<DeclRefExpr>(EI->getAssociatedExpression()))
            IsVariableUsedInMapClause |= EI->getAssociatedDeclaration() == D;

          ++EI;
          if (EI == EE)
            return false;

          if (isa<ArraySubscriptExpr>(EI->getAssociatedExpression()) ||
              isa<OMPArraySectionExpr>(EI->getAssociatedExpression()) ||
              isa<MemberExpr>(EI->getAssociatedExpression())) {
            IsVariableAssociatedWithSection = true;
            // There is nothing more we need to know about this variable.
            return true;
          }

          // Keep looking for more map info.
          return false;
        });

    if (IsVariableUsedInMapClause) {
      // If variable is identified in a map clause it is always captured by
      // reference except if it is a pointer that is dereferenced somehow.
      IsByRef = !(Ty->isPointerType() && IsVariableAssociatedWithSection);
    } else {
      // By default, all the data that has a scalar type is mapped by copy
      // (except for reduction variables).
      IsByRef =
          !Ty->isScalarType() ||
          DSAStack->getDefaultDMAAtLevel(Level) == DMA_tofrom_scalar ||
          DSAStack->hasExplicitDSA(
              D, [](OpenMPClauseKind K) { return K == OMPC_reduction; }, Level);
    }
  }

  if (IsByRef && Ty.getNonReferenceType()->isScalarType()) {
    IsByRef =
        !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>() &&
          !cast<OMPCapturedExprDecl>(D)->getInit()->isGLValue());
  }

  // When passing data by copy, we need to make sure it fits the uintptr size
  // and alignment, because the runtime library only deals with uintptr types.
  // If it does not fit the uintptr size, we need to pass the data by reference
  // instead.
  if (!IsByRef &&
      (Ctx.getTypeSizeInChars(Ty) >
           Ctx.getTypeSizeInChars(Ctx.getUIntPtrType()) ||
       Ctx.getDeclAlign(D) > Ctx.getTypeAlignInChars(Ctx.getUIntPtrType()))) {
    IsByRef = true;
  }

  return IsByRef;
}

unsigned Sema::getOpenMPNestingLevel() const {
  assert(getLangOpts().OpenMP);
  return DSAStack->getNestingLevel();
}

bool Sema::isInOpenMPTargetExecutionDirective() const {
  return (isOpenMPTargetExecutionDirective(DSAStack->getCurrentDirective()) &&
          !DSAStack->isClauseParsingMode()) ||
         DSAStack->hasDirective(
             [](OpenMPDirectiveKind K, const DeclarationNameInfo &,
                SourceLocation) -> bool {
               return isOpenMPTargetExecutionDirective(K);
             },
             false);
}

VarDecl *Sema::isOpenMPCapturedDecl(ValueDecl *D) {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");
  D = getCanonicalDecl(D);

  // If we are attempting to capture a global variable in a directive with
  // 'target' we return true so that this global is also mapped to the device.
  //
  auto *VD = dyn_cast<VarDecl>(D);
  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;
    } 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;
    }
  }

  if (DSAStack->getCurrentDirective() != OMPD_unknown &&
      (!DSAStack->isClauseParsingMode() ||
       DSAStack->getParentDirective() != OMPD_unknown)) {
    auto &&Info = DSAStack->isLoopControlVariable(D);
    if (Info.first ||
        (VD && VD->hasLocalStorage() &&
         isParallelOrTaskRegion(DSAStack->getCurrentDirective())) ||
        (VD && DSAStack->isForceVarCapturing()))
      return VD ? VD : Info.second;
    DSAStackTy::DSAVarData DVarPrivate =
        DSAStack->getTopDSA(D, DSAStack->isClauseParsingMode());
    if (DVarPrivate.CKind != OMPC_unknown && isOpenMPPrivate(DVarPrivate.CKind))
      return VD ? VD : cast<VarDecl>(DVarPrivate.PrivateCopy->getDecl());
    DVarPrivate = DSAStack->hasDSA(D, isOpenMPPrivate,
                                   [](OpenMPDirectiveKind) { return true; },
                                   DSAStack->isClauseParsingMode());
    if (DVarPrivate.CKind != OMPC_unknown)
      return VD ? VD : cast<VarDecl>(DVarPrivate.PrivateCopy->getDecl());
  }
  return nullptr;
}

void Sema::adjustOpenMPTargetScopeIndex(unsigned &FunctionScopesIndex,
                                        unsigned Level) const {
  SmallVector<OpenMPDirectiveKind, 4> Regions;
  getOpenMPCaptureRegions(Regions, DSAStack->getDirective(Level));
  FunctionScopesIndex -= Regions.size();
}

bool Sema::isOpenMPPrivateDecl(const ValueDecl *D, unsigned Level) const {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");
  return DSAStack->hasExplicitDSA(
             D, [](OpenMPClauseKind K) { return K == OMPC_private; }, Level) ||
         (DSAStack->isClauseParsingMode() &&
          DSAStack->getClauseParsingMode() == OMPC_private) ||
         // Consider taskgroup reduction descriptor variable a private to avoid
         // possible capture in the region.
         (DSAStack->hasExplicitDirective(
              [](OpenMPDirectiveKind K) { return K == OMPD_taskgroup; },
              Level) &&
          DSAStack->isTaskgroupReductionRef(D, Level));
}

void Sema::setOpenMPCaptureKind(FieldDecl *FD, const ValueDecl *D,
                                unsigned Level) {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");
  D = getCanonicalDecl(D);
  OpenMPClauseKind OMPC = OMPC_unknown;
  for (unsigned I = DSAStack->getNestingLevel() + 1; I > Level; --I) {
    const unsigned NewLevel = I - 1;
    if (DSAStack->hasExplicitDSA(D,
                                 [&OMPC](const OpenMPClauseKind K) {
                                   if (isOpenMPPrivate(K)) {
                                     OMPC = K;
                                     return true;
                                   }
                                   return false;
                                 },
                                 NewLevel))
      break;
    if (DSAStack->checkMappableExprComponentListsForDeclAtLevel(
            D, NewLevel,
            [](OMPClauseMappableExprCommon::MappableExprComponentListRef,
               OpenMPClauseKind) { return true; })) {
      OMPC = OMPC_map;
      break;
    }
    if (DSAStack->hasExplicitDirective(isOpenMPTargetExecutionDirective,
                                       NewLevel)) {
      OMPC = OMPC_map;
      if (D->getType()->isScalarType() &&
          DSAStack->getDefaultDMAAtLevel(NewLevel) !=
              DefaultMapAttributes::DMA_tofrom_scalar)
        OMPC = OMPC_firstprivate;
      break;
    }
  }
  if (OMPC != OMPC_unknown)
    FD->addAttr(OMPCaptureKindAttr::CreateImplicit(Context, OMPC));
}

bool Sema::isOpenMPTargetCapturedDecl(const ValueDecl *D,
                                      unsigned Level) const {
  assert(LangOpts.OpenMP && "OpenMP is not allowed");
  // Return true if the current level is no longer enclosed in a target region.

  const auto *VD = dyn_cast<VarDecl>(D);
  return VD && !VD->hasLocalStorage() &&
         DSAStack->hasExplicitDirective(isOpenMPTargetExecutionDirective,
                                        Level);
}

void Sema::DestroyDataSharingAttributesStack() { delete DSAStack; }

void Sema::StartOpenMPDSABlock(OpenMPDirectiveKind DKind,
                               const DeclarationNameInfo &DirName,
                               Scope *CurScope, SourceLocation Loc) {
  DSAStack->push(DKind, DirName, CurScope, Loc);
  PushExpressionEvaluationContext(
      ExpressionEvaluationContext::PotentiallyEvaluated);
}

void Sema::StartOpenMPClause(OpenMPClauseKind K) {
  DSAStack->setClauseParsingMode(K);
}

void Sema::EndOpenMPClause() {
  DSAStack->setClauseParsingMode(/*K=*/OMPC_unknown);
}

void Sema::EndOpenMPDSABlock(Stmt *CurDirective) {
  // OpenMP [2.14.3.5, Restrictions, C/C++, p.1]
  //  A variable of class type (or array thereof) that appears in a lastprivate
  //  clause requires an accessible, unambiguous default constructor for the
  //  class type, unless the list item is also specified in a firstprivate
  //  clause.
  if (const auto *D = dyn_cast_or_null<OMPExecutableDirective>(CurDirective)) {
    for (OMPClause *C : D->clauses()) {
      if (auto *Clause = dyn_cast<OMPLastprivateClause>(C)) {
        SmallVector<Expr *, 8> PrivateCopies;
        for (Expr *DE : Clause->varlists()) {
          if (DE->isValueDependent() || DE->isTypeDependent()) {
            PrivateCopies.push_back(nullptr);
            continue;
          }
          auto *DRE = cast<DeclRefExpr>(DE->IgnoreParens());
          auto *VD = cast<VarDecl>(DRE->getDecl());
          QualType Type = VD->getType().getNonReferenceType();
          const DSAStackTy::DSAVarData DVar =
              DSAStack->getTopDSA(VD, /*FromParent=*/false);
          if (DVar.CKind == OMPC_lastprivate) {
            // Generate helper private variable and initialize it with the
            // default value. The address of the original variable is replaced
            // by the address of the new private variable in CodeGen. This new
            // variable is not added to IdResolver, so the code in the OpenMP
            // region uses original variable for proper diagnostics.
            VarDecl *VDPrivate = buildVarDecl(
                *this, DE->getExprLoc(), Type.getUnqualifiedType(),
                VD->getName(), VD->hasAttrs() ? &VD->getAttrs() : nullptr, DRE);
            ActOnUninitializedDecl(VDPrivate);
            if (VDPrivate->isInvalidDecl())
              continue;
            PrivateCopies.push_back(buildDeclRefExpr(
                *this, VDPrivate, DE->getType(), DE->getExprLoc()));
          } else {
            // The variable is also a firstprivate, so initialization sequence
            // for private copy is generated already.
            PrivateCopies.push_back(nullptr);
          }
        }
        // Set initializers to private copies if no errors were found.
        if (PrivateCopies.size() == Clause->varlist_size())
          Clause->setPrivateCopies(PrivateCopies);
      }
    }
  }

  DSAStack->pop();
  DiscardCleanupsInEvaluationContext();
  PopExpressionEvaluationContext();
}

static bool FinishOpenMPLinearClause(OMPLinearClause &Clause, DeclRefExpr *IV,
                                     Expr *NumIterations, Sema &SemaRef,
                                     Scope *S, DSAStackTy *Stack);

namespace {

class VarDeclFilterCCC final : public CorrectionCandidateCallback {
private:
  Sema &SemaRef;

public:
  explicit VarDeclFilterCCC(Sema &S) : SemaRef(S) {}
  bool ValidateCandidate(const TypoCorrection &Candidate) override {
    NamedDecl *ND = Candidate.getCorrectionDecl();
    if (const auto *VD = dyn_cast_or_null<VarDecl>(ND)) {
      return VD->hasGlobalStorage() &&
             SemaRef.isDeclInScope(ND, SemaRef.getCurLexicalContext(),
                                   SemaRef.getCurScope());
    }
    return false;
  }
};

class VarOrFuncDeclFilterCCC final : public CorrectionCandidateCallback {
private:
  Sema &SemaRef;

public:
  explicit VarOrFuncDeclFilterCCC(Sema &S) : SemaRef(S) {}
  bool ValidateCandidate(const TypoCorrection &Candidate) override {
    NamedDecl *ND = Candidate.getCorrectionDecl();
    if (ND && (isa<VarDecl>(ND) || isa<FunctionDecl>(ND))) {
      return SemaRef.isDeclInScope(ND, SemaRef.getCurLexicalContext(),
                                   SemaRef.getCurScope());
    }
    return false;
  }
};

} // namespace

ExprResult Sema::ActOnOpenMPIdExpression(Scope *CurScope,
                                         CXXScopeSpec &ScopeSpec,
                                         const DeclarationNameInfo &Id) {
  LookupResult Lookup(*this, Id, LookupOrdinaryName);
  LookupParsedName(Lookup, CurScope, &ScopeSpec, true);

  if (Lookup.isAmbiguous())
    return ExprError();

  VarDecl *VD;
  if (!Lookup.isSingleResult()) {
    if (TypoCorrection Corrected = CorrectTypo(
            Id, LookupOrdinaryName, CurScope, nullptr,
            llvm::make_unique<VarDeclFilterCCC>(*this), CTK_ErrorRecovery)) {
      diagnoseTypo(Corrected,
                   PDiag(Lookup.empty()
                             ? diag::err_undeclared_var_use_suggest
                             : diag::err_omp_expected_var_arg_suggest)
                       << Id.getName());
      VD = Corrected.getCorrectionDeclAs<VarDecl>();
    } else {
      Diag(Id.getLoc(), Lookup.empty() ? diag::err_undeclared_var_use
                                       : diag::err_omp_expected_var_arg)
          << Id.getName();
      return ExprError();
    }
  } else if (!(VD = Lookup.getAsSingle<VarDecl>())) {
    Diag(Id.getLoc(), diag::err_omp_expected_var_arg) << Id.getName();
    Diag(Lookup.getFoundDecl()->getLocation(), diag::note_declared_at);
    return ExprError();
  }
  Lookup.suppressDiagnostics();

  // OpenMP [2.9.2, Syntax, C/C++]
  //   Variables must be file-scope, namespace-scope, or static block-scope.
  if (!VD->hasGlobalStorage()) {
    Diag(Id.getLoc(), diag::err_omp_global_var_arg)
        << getOpenMPDirectiveName(OMPD_threadprivate) << !VD->isStaticLocal();
    bool IsDecl =
        VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
    Diag(VD->getLocation(),
         IsDecl ? diag::note_previous_decl : diag::note_defined_here)
        << VD;
    return ExprError();
  }

  VarDecl *CanonicalVD = VD->getCanonicalDecl();
  NamedDecl *ND = CanonicalVD;
  // OpenMP [2.9.2, Restrictions, C/C++, p.2]
  //   A threadprivate directive for file-scope variables must appear outside
  //   any definition or declaration.
  if (CanonicalVD->getDeclContext()->isTranslationUnit() &&
      !getCurLexicalContext()->isTranslationUnit()) {
    Diag(Id.getLoc(), diag::err_omp_var_scope)
        << getOpenMPDirectiveName(OMPD_threadprivate) << VD;
    bool IsDecl =
        VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
    Diag(VD->getLocation(),
         IsDecl ? diag::note_previous_decl : diag::note_defined_here)
        << VD;
    return ExprError();
  }
  // OpenMP [2.9.2, Restrictions, C/C++, p.3]
  //   A threadprivate directive for static class member variables must appear
  //   in the class definition, in the same scope in which the member
  //   variables are declared.
  if (CanonicalVD->isStaticDataMember() &&
      !CanonicalVD->getDeclContext()->Equals(getCurLexicalContext())) {
    Diag(Id.getLoc(), diag::err_omp_var_scope)
        << getOpenMPDirectiveName(OMPD_threadprivate) << VD;
    bool IsDecl =
        VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
    Diag(VD->getLocation(),
         IsDecl ? diag::note_previous_decl : diag::note_defined_here)
        << VD;
    return ExprError();
  }
  // OpenMP [2.9.2, Restrictions, C/C++, p.4]
  //   A threadprivate directive for namespace-scope variables must appear
  //   outside any definition or declaration other than the namespace
  //   definition itself.
  if (CanonicalVD->getDeclContext()->isNamespace() &&
      (!getCurLexicalContext()->isFileContext() ||
       !getCurLexicalContext()->Encloses(CanonicalVD->getDeclContext()))) {
    Diag(Id.getLoc(), diag::err_omp_var_scope)
        << getOpenMPDirectiveName(OMPD_threadprivate) << VD;
    bool IsDecl =
        VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
    Diag(VD->getLocation(),
         IsDecl ? diag::note_previous_decl : diag::note_defined_here)
        << VD;
    return ExprError();
  }
  // OpenMP [2.9.2, Restrictions, C/C++, p.6]
  //   A threadprivate directive for static block-scope variables must appear
  //   in the scope of the variable and not in a nested scope.
  if (CanonicalVD->isStaticLocal() && CurScope &&
      !isDeclInScope(ND, getCurLexicalContext(), CurScope)) {
    Diag(Id.getLoc(), diag::err_omp_var_scope)
        << getOpenMPDirectiveName(OMPD_threadprivate) << VD;
    bool IsDecl =
        VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
    Diag(VD->getLocation(),
         IsDecl ? diag::note_previous_decl : diag::note_defined_here)
        << VD;
    return ExprError();
  }

  // OpenMP [2.9.2, Restrictions, C/C++, p.2-6]
  //   A threadprivate directive must lexically precede all references to any
  //   of the variables in its list.
  if (VD->isUsed() && !DSAStack->isThreadPrivate(VD)) {
    Diag(Id.getLoc(), diag::err_omp_var_used)
        << getOpenMPDirectiveName(OMPD_threadprivate) << VD;
    return ExprError();
  }

  QualType ExprType = VD->getType().getNonReferenceType();
  return DeclRefExpr::Create(Context, NestedNameSpecifierLoc(),
                             SourceLocation(), VD,
                             /*RefersToEnclosingVariableOrCapture=*/false,
                             Id.getLoc(), ExprType, VK_LValue);
}

Sema::DeclGroupPtrTy
Sema::ActOnOpenMPThreadprivateDirective(SourceLocation Loc,
                                        ArrayRef<Expr *> VarList) {
  if (OMPThreadPrivateDecl *D = CheckOMPThreadPrivateDecl(Loc, VarList)) {
    CurContext->addDecl(D);
    return DeclGroupPtrTy::make(DeclGroupRef(D));
  }
  return nullptr;
}

namespace {
class LocalVarRefChecker final
    : public ConstStmtVisitor<LocalVarRefChecker, bool> {
  Sema &SemaRef;

public:
  bool VisitDeclRefExpr(const DeclRefExpr *E) {
    if (const auto *VD = dyn_cast<VarDecl>(E->getDecl())) {
      if (VD->hasLocalStorage()) {
        SemaRef.Diag(E->getBeginLoc(),
                     diag::err_omp_local_var_in_threadprivate_init)
            << E->getSourceRange();
        SemaRef.Diag(VD->getLocation(), diag::note_defined_here)
            << VD << VD->getSourceRange();
        return true;
      }
    }
    return false;
  }
  bool VisitStmt(const Stmt *S) {
    for (const Stmt *Child : S->children()) {
      if (Child && Visit(Child))
        return true;
    }
    return false;
  }
  explicit LocalVarRefChecker(Sema &SemaRef) : SemaRef(SemaRef) {}
};
} // namespace

OMPThreadPrivateDecl *
Sema::CheckOMPThreadPrivateDecl(SourceLocation Loc, ArrayRef<Expr *> VarList) {
  SmallVector<Expr *, 8> Vars;
  for (Expr *RefExpr : VarList) {
    auto *DE = cast<DeclRefExpr>(RefExpr);
    auto *VD = cast<VarDecl>(DE->getDecl());
    SourceLocation ILoc = DE->getExprLoc();

    // Mark variable as used.
    VD->setReferenced();
    VD->markUsed(Context);

    QualType QType = VD->getType();
    if (QType->isDependentType() || QType->isInstantiationDependentType()) {
      // It will be analyzed later.
      Vars.push_back(DE);
      continue;
    }

    // OpenMP [2.9.2, Restrictions, C/C++, p.10]
    //   A threadprivate variable must not have an incomplete type.
    if (RequireCompleteType(ILoc, VD->getType(),
                            diag::err_omp_threadprivate_incomplete_type)) {
      continue;
    }

    // OpenMP [2.9.2, Restrictions, C/C++, p.10]
    //   A threadprivate variable must not have a reference type.
    if (VD->getType()->isReferenceType()) {
      Diag(ILoc, diag::err_omp_ref_type_arg)
          << getOpenMPDirectiveName(OMPD_threadprivate) << VD->getType();
      bool IsDecl =
          VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
      Diag(VD->getLocation(),
           IsDecl ? diag::note_previous_decl : diag::note_defined_here)
          << VD;
      continue;
    }

    // Check if this is a TLS variable. If TLS is not being supported, produce
    // the corresponding diagnostic.
    if ((VD->getTLSKind() != VarDecl::TLS_None &&
         !(VD->hasAttr<OMPThreadPrivateDeclAttr>() &&
           getLangOpts().OpenMPUseTLS &&
           getASTContext().getTargetInfo().isTLSSupported())) ||
        (VD->getStorageClass() == SC_Register && VD->hasAttr<AsmLabelAttr>() &&
         !VD->isLocalVarDecl())) {
      Diag(ILoc, diag::err_omp_var_thread_local)
          << VD << ((VD->getTLSKind() != VarDecl::TLS_None) ? 0 : 1);
      bool IsDecl =
          VD->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly;
      Diag(VD->getLocation(),
           IsDecl ? diag::note_previous_decl : diag::note_defined_here)
          << VD;
      continue;
    }

    // Check if initial value of threadprivate variable reference variable with
    // local storage (it is not supported by runtime).
    if (const Expr *Init = VD->getAnyInitializer()) {
      LocalVarRefChecker Checker(*this);
      if (Checker.Visit(Init))
        continue;
    }

    Vars.push_back(RefExpr);
    DSAStack->addDSA(VD, DE, OMPC_threadprivate);
    VD->addAttr(OMPThreadPrivateDeclAttr::CreateImplicit(
        Context, SourceRange(Loc, Loc)));
    if (ASTMutationListener *ML = Context.getASTMutationListener())
      ML->DeclarationMarkedOpenMPThreadPrivate(VD);
  }
  OMPThreadPrivateDecl *D = nullptr;
  if (!Vars.empty()) {
    D = OMPThreadPrivateDecl::Create(Context, getCurLexicalContext(), Loc,
                                     Vars);
    D->setAccess(AS_public);
  }
  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,
                              bool IsLoopIterVar = false) {
  if (DVar.RefExpr) {
    SemaRef.Diag(DVar.RefExpr->getExprLoc(), diag::note_omp_explicit_dsa)
        << getOpenMPClauseName(DVar.CKind);
    return;
  }
  enum {
    PDSA_StaticMemberShared,
    PDSA_StaticLocalVarShared,
    PDSA_LoopIterVarPrivate,
    PDSA_LoopIterVarLinear,
    PDSA_LoopIterVarLastprivate,
    PDSA_ConstVarShared,
    PDSA_GlobalVarShared,
    PDSA_TaskVarFirstprivate,
    PDSA_LocalVarPrivate,
    PDSA_Implicit
  } Reason = PDSA_Implicit;
  bool ReportHint = false;
  auto ReportLoc = D->getLocation();
  auto *VD = dyn_cast<VarDecl>(D);
  if (IsLoopIterVar) {
    if (DVar.CKind == OMPC_private)
      Reason = PDSA_LoopIterVarPrivate;
    else if (DVar.CKind == OMPC_lastprivate)
      Reason = PDSA_LoopIterVarLastprivate;
    else
      Reason = PDSA_LoopIterVarLinear;
  } else if (isOpenMPTaskingDirective(DVar.DKind) &&
             DVar.CKind == OMPC_firstprivate) {
    Reason = PDSA_TaskVarFirstprivate;
    ReportLoc = DVar.ImplicitDSALoc;
  } else if (VD && VD->isStaticLocal())
    Reason = PDSA_StaticLocalVarShared;
  else if (VD && VD->isStaticDataMember())
    Reason = PDSA_StaticMemberShared;
  else if (VD && VD->isFileVarDecl())
    Reason = PDSA_GlobalVarShared;
  else if (D->getType().isConstant(SemaRef.getASTContext()))
    Reason = PDSA_ConstVarShared;
  else if (VD && VD->isLocalVarDecl() && DVar.CKind == OMPC_private) {
    ReportHint = true;
    Reason = PDSA_LocalVarPrivate;
  }
  if (Reason != PDSA_Implicit) {
    SemaRef.Diag(ReportLoc, diag::note_omp_predetermined_dsa)
        << Reason << ReportHint
        << getOpenMPDirectiveName(Stack->getCurrentDirective());
  } else if (DVar.ImplicitDSALoc.isValid()) {
    SemaRef.Diag(DVar.ImplicitDSALoc, diag::note_omp_implicit_dsa)
        << getOpenMPClauseName(DVar.CKind);
  }
}

namespace {
class DSAAttrChecker final : public StmtVisitor<DSAAttrChecker, void> {
  DSAStackTy *Stack;
  Sema &SemaRef;
  bool ErrorFound = false;
  CapturedStmt *CS = nullptr;
  llvm::SmallVector<Expr *, 4> ImplicitFirstprivate;
  llvm::SmallVector<Expr *, 4> ImplicitMap;
  Sema::VarsWithInheritedDSAType VarsWithInheritedDSA;
  llvm::SmallDenseSet<const ValueDecl *, 4> ImplicitDeclarations;

public:
  void VisitDeclRefExpr(DeclRefExpr *E) {
    if (E->isTypeDependent() || E->isValueDependent() ||
        E->containsUnexpandedParameterPack() || E->isInstantiationDependent())
      return;
    if (auto *VD = dyn_cast<VarDecl>(E->getDecl())) {
      VD = VD->getCanonicalDecl();
      // Skip internally declared variables.
      if (VD->hasLocalStorage() && !CS->capturesVariable(VD))
        return;

      DSAStackTy::DSAVarData DVar = Stack->getTopDSA(VD, /*FromParent=*/false);
      // Check if the variable has explicit DSA set and stop analysis if it so.
      if (DVar.RefExpr || !ImplicitDeclarations.insert(VD).second)
        return;

      // Skip internally declared static variables.
      llvm::Optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
          OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD);
      if (VD->hasGlobalStorage() && !CS->capturesVariable(VD) &&
          (!Res || *Res != OMPDeclareTargetDeclAttr::MT_Link))
        return;

      SourceLocation ELoc = E->getExprLoc();
      OpenMPDirectiveKind DKind = Stack->getCurrentDirective();
      // The default(none) clause requires that each variable that is referenced
      // in the construct, and does not have a predetermined data-sharing
      // 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) &&
          VarsWithInheritedDSA.count(VD) == 0) {
        VarsWithInheritedDSA[VD] = E;
        return;
      }

      if (isOpenMPTargetExecutionDirective(DKind) &&
          !Stack->isLoopControlVariable(VD).first) {
        if (!Stack->checkMappableExprComponentListsForDecl(
                VD, /*CurrentRegionOnly=*/true,
                [](OMPClauseMappableExprCommon::MappableExprComponentListRef
                       StackComponents,
                   OpenMPClauseKind) {
                  // Variable is used if it has been marked as an array, array
                  // section or the variable iself.
                  return StackComponents.size() == 1 ||
                         std::all_of(
                             std::next(StackComponents.rbegin()),
                             StackComponents.rend(),
                             [](const OMPClauseMappableExprCommon::
                                    MappableComponent &MC) {
                               return MC.getAssociatedDeclaration() ==
                                          nullptr &&
                                      (isa<OMPArraySectionExpr>(
                                           MC.getAssociatedExpression()) ||
                                       isa<ArraySubscriptExpr>(
                                           MC.getAssociatedExpression()));
                             });
                })) {
          bool IsFirstprivate = false;
          // By default lambdas are captured as firstprivates.
          if (const auto *RD =
                  VD->getType().getNonReferenceType()->getAsCXXRecordDecl())
            IsFirstprivate = RD->isLambda();
          IsFirstprivate =
              IsFirstprivate ||
              (VD->getType().getNonReferenceType()->isScalarType() &&
               Stack->getDefaultDMA() != DMA_tofrom_scalar && !Res);
          if (IsFirstprivate)
            ImplicitFirstprivate.emplace_back(E);
          else
            ImplicitMap.emplace_back(E);
          return;
        }
      }

      // OpenMP [2.9.3.6, Restrictions, p.2]
      //  A list item that appears in a reduction clause of the innermost
      //  enclosing worksharing or parallel construct may not be accessed in an
      //  explicit task.
      DVar = Stack->hasInnermostDSA(
          VD, [](OpenMPClauseKind C) { return C == OMPC_reduction; },
          [](OpenMPDirectiveKind K) {
            return isOpenMPParallelDirective(K) ||
                   isOpenMPWorksharingDirective(K) || isOpenMPTeamsDirective(K);
          },
          /*FromParent=*/true);
      if (isOpenMPTaskingDirective(DKind) && DVar.CKind == OMPC_reduction) {
        ErrorFound = true;
        SemaRef.Diag(ELoc, diag::err_omp_reduction_in_task);
        reportOriginalDsa(SemaRef, Stack, VD, DVar);
        return;
      }

      // Define implicit data-sharing attributes for task.
      DVar = Stack->getImplicitDSA(VD, /*FromParent=*/false);
      if (isOpenMPTaskingDirective(DKind) && DVar.CKind != OMPC_shared &&
          !Stack->isLoopControlVariable(VD).first)
        ImplicitFirstprivate.push_back(E);
    }
  }
  void VisitMemberExpr(MemberExpr *E) {
    if (E->isTypeDependent() || E->isValueDependent() ||
        E->containsUnexpandedParameterPack() || E->isInstantiationDependent())
      return;
    auto *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
    OpenMPDirectiveKind DKind = Stack->getCurrentDirective();
    if (isa<CXXThisExpr>(E->getBase()->IgnoreParens())) {
      if (!FD)
        return;
      DSAStackTy::DSAVarData DVar = Stack->getTopDSA(FD, /*FromParent=*/false);
      // Check if the variable has explicit DSA set and stop analysis if it
      // so.
      if (DVar.RefExpr || !ImplicitDeclarations.insert(FD).second)
        return;

      if (isOpenMPTargetExecutionDirective(DKind) &&
          !Stack->isLoopControlVariable(FD).first &&
          !Stack->checkMappableExprComponentListsForDecl(
              FD, /*CurrentRegionOnly=*/true,
              [](OMPClauseMappableExprCommon::MappableExprComponentListRef
                     StackComponents,
                 OpenMPClauseKind) {
                return isa<CXXThisExpr>(
                    cast<MemberExpr>(
                        StackComponents.back().getAssociatedExpression())
                        ->getBase()
                        ->IgnoreParens());
              })) {
        // OpenMP 4.5 [2.15.5.1, map Clause, Restrictions, C/C++, p.3]
        //  A bit-field cannot appear in a map clause.
        //
        if (FD->isBitField())
          return;
        ImplicitMap.emplace_back(E);
        return;
      }

      SourceLocation ELoc = E->getExprLoc();
      // OpenMP [2.9.3.6, Restrictions, p.2]
      //  A list item that appears in a reduction clause of the innermost
      //  enclosing worksharing or parallel construct may not be accessed in
      //  an  explicit task.
      DVar = Stack->hasInnermostDSA(
          FD, [](OpenMPClauseKind C) { return C == OMPC_reduction; },
          [](OpenMPDirectiveKind K) {
            return isOpenMPParallelDirective(K) ||
                   isOpenMPWorksharingDirective(K) || isOpenMPTeamsDirective(K);
          },
          /*FromParent=*/true);
      if (isOpenMPTaskingDirective(DKind) && DVar.CKind == OMPC_reduction) {
        ErrorFound = true;
        SemaRef.Diag(ELoc, diag::err_omp_reduction_in_task);
        reportOriginalDsa(SemaRef, Stack, FD, DVar);
        return;
      }

      // 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);
      return;
    }
    if (isOpenMPTargetExecutionDirective(DKind)) {
      OMPClauseMappableExprCommon::MappableExprComponentList CurComponents;
      if (!checkMapClauseExpressionBase(SemaRef, E, CurComponents, OMPC_map,
                                        /*NoDiagnose=*/true))
        return;
      const auto *VD = cast<ValueDecl>(
          CurComponents.back().getAssociatedDeclaration()->getCanonicalDecl());
      if (!Stack->checkMappableExprComponentListsForDecl(
              VD, /*CurrentRegionOnly=*/true,
              [&CurComponents](
                  OMPClauseMappableExprCommon::MappableExprComponentListRef
                      StackComponents,
                  OpenMPClauseKind) {
                auto CCI = CurComponents.rbegin();
                auto CCE = CurComponents.rend();
                for (const auto &SC : llvm::reverse(StackComponents)) {
                  // Do both expressions have the same kind?
                  if (CCI->getAssociatedExpression()->getStmtClass() !=
                      SC.getAssociatedExpression()->getStmtClass())
                    if (!(isa<OMPArraySectionExpr>(
                              SC.getAssociatedExpression()) &&
                          isa<ArraySubscriptExpr>(
                              CCI->getAssociatedExpression())))
                      return false;

                  const Decl *CCD = CCI->getAssociatedDeclaration();
                  const Decl *SCD = SC.getAssociatedDeclaration();
                  CCD = CCD ? CCD->getCanonicalDecl() : nullptr;
                  SCD = SCD ? SCD->getCanonicalDecl() : nullptr;
                  if (SCD != CCD)
                    return false;
                  std::advance(CCI, 1);
                  if (CCI == CCE)
                    break;
                }
                return true;
              })) {
        Visit(E->getBase());
      }
    } else {
      Visit(E->getBase());
    }
  }
  void VisitOMPExecutableDirective(OMPExecutableDirective *S) {
    for (OMPClause *C : S->clauses()) {
      // Skip analysis of arguments of implicitly defined firstprivate clause
      // for task|target directives.
      // Skip analysis of arguments of implicitly defined map clause for target
      // directives.
      if (C && !((isa<OMPFirstprivateClause>(C) || isa<OMPMapClause>(C)) &&
                 C->isImplicit())) {
        for (Stmt *CC : C->children()) {
          if (CC)
            Visit(CC);
        }
      }
    }
  }
  void VisitStmt(Stmt *S) {
    for (Stmt *C : S->children()) {
      if (C && !isa<OMPExecutableDirective>(C))
        Visit(C);
    }
  }

  bool isErrorFound() const { return ErrorFound; }
  ArrayRef<Expr *> getImplicitFirstprivate() const {
    return ImplicitFirstprivate;
  }
  ArrayRef<Expr *> getImplicitMap() const { return ImplicitMap; }
  const Sema::VarsWithInheritedDSAType &getVarsWithInheritedDSA() const {
    return VarsWithInheritedDSA;
  }

  DSAAttrChecker(DSAStackTy *S, Sema &SemaRef, CapturedStmt *CS)
      : Stack(S), SemaRef(SemaRef), ErrorFound(false), CS(CS) {}
};
} // namespace

void Sema::ActOnOpenMPRegionStart(OpenMPDirectiveKind DKind, Scope *CurScope) {
  switch (DKind) {
  case OMPD_parallel:
  case OMPD_parallel_for:
  case OMPD_parallel_for_simd:
  case OMPD_parallel_sections:
  case OMPD_teams:
  case OMPD_teams_distribute:
  case OMPD_teams_distribute_simd: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    break;
  }
  case OMPD_target_teams:
  case OMPD_target_parallel:
  case OMPD_target_parallel_for:
  case OMPD_target_parallel_for_simd:
  case OMPD_target_teams_distribute:
  case OMPD_target_teams_distribute_simd: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, AlwaysInlineAttr::Keyword_forceinline));
    Sema::CapturedParamNameType ParamsTarget[] = {
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'target' with no implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTarget);
    Sema::CapturedParamNameType ParamsTeamsOrParallel[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'teams' or 'parallel'.  Both regions have
    // the same implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTeamsOrParallel);
    break;
  }
  case OMPD_target:
  case OMPD_target_simd: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, AlwaysInlineAttr::Keyword_forceinline));
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             std::make_pair(StringRef(), QualType()));
    break;
  }
  case OMPD_simd:
  case OMPD_for:
  case OMPD_for_simd:
  case OMPD_sections:
  case OMPD_section:
  case OMPD_single:
  case OMPD_master:
  case OMPD_critical:
  case OMPD_taskgroup:
  case OMPD_distribute:
  case OMPD_distribute_simd:
  case OMPD_ordered:
  case OMPD_atomic:
  case OMPD_target_data: {
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    break;
  }
  case OMPD_task: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, AlwaysInlineAttr::Keyword_forceinline));
    break;
  }
  case OMPD_taskloop:
  case OMPD_taskloop_simd: {
    QualType KmpInt32Ty =
        Context.getIntTypeForBitwidth(/*DestWidth=*/32, /*Signed=*/1)
            .withConst();
    QualType KmpUInt64Ty =
        Context.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/0)
            .withConst();
    QualType KmpInt64Ty =
        Context.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/1)
            .withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(".lb.", KmpUInt64Ty),
        std::make_pair(".ub.", KmpUInt64Ty),
        std::make_pair(".st.", KmpInt64Ty),
        std::make_pair(".liter.", KmpInt32Ty),
        std::make_pair(".reductions.", VoidPtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, AlwaysInlineAttr::Keyword_forceinline));
    break;
  }
  case OMPD_distribute_parallel_for_simd:
  case OMPD_distribute_parallel_for: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(".previous.lb.", Context.getSizeType().withConst()),
        std::make_pair(".previous.ub.", Context.getSizeType().withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    break;
  }
  case OMPD_target_teams_distribute_parallel_for:
  case OMPD_target_teams_distribute_parallel_for_simd: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();

    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, AlwaysInlineAttr::Keyword_forceinline));
    Sema::CapturedParamNameType ParamsTarget[] = {
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'target' with no implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTarget);

    Sema::CapturedParamNameType ParamsTeams[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'target' with no implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTeams);

    Sema::CapturedParamNameType ParamsParallel[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(".previous.lb.", Context.getSizeType().withConst()),
        std::make_pair(".previous.ub.", Context.getSizeType().withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'teams' or 'parallel'.  Both regions have
    // the same implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsParallel);
    break;
  }

  case OMPD_teams_distribute_parallel_for:
  case OMPD_teams_distribute_parallel_for_simd: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();

    Sema::CapturedParamNameType ParamsTeams[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'target' with no implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsTeams);

    Sema::CapturedParamNameType ParamsParallel[] = {
        std::make_pair(".global_tid.", KmpInt32PtrTy),
        std::make_pair(".bound_tid.", KmpInt32PtrTy),
        std::make_pair(".previous.lb.", Context.getSizeType().withConst()),
        std::make_pair(".previous.ub.", Context.getSizeType().withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    // Start a captured region for 'teams' or 'parallel'.  Both regions have
    // the same implicit parameters.
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             ParamsParallel);
    break;
  }
  case OMPD_target_update:
  case OMPD_target_enter_data:
  case OMPD_target_exit_data: {
    QualType KmpInt32Ty = Context.getIntTypeForBitwidth(32, 1).withConst();
    QualType VoidPtrTy = Context.VoidPtrTy.withConst().withRestrict();
    QualType KmpInt32PtrTy =
        Context.getPointerType(KmpInt32Ty).withConst().withRestrict();
    QualType Args[] = {VoidPtrTy};
    FunctionProtoType::ExtProtoInfo EPI;
    EPI.Variadic = true;
    QualType CopyFnType = Context.getFunctionType(Context.VoidTy, Args, EPI);
    Sema::CapturedParamNameType Params[] = {
        std::make_pair(".global_tid.", KmpInt32Ty),
        std::make_pair(".part_id.", KmpInt32PtrTy),
        std::make_pair(".privates.", VoidPtrTy),
        std::make_pair(
            ".copy_fn.",
            Context.getPointerType(CopyFnType).withConst().withRestrict()),
        std::make_pair(".task_t.", Context.VoidPtrTy.withConst()),
        std::make_pair(StringRef(), QualType()) // __context with shared vars
    };
    ActOnCapturedRegionStart(DSAStack->getConstructLoc(), CurScope, CR_OpenMP,
                             Params);
    // Mark this captured region as inlined, because we don't use outlined
    // function directly.
    getCurCapturedRegion()->TheCapturedDecl->addAttr(
        AlwaysInlineAttr::CreateImplicit(
            Context, AlwaysInlineAttr::Keyword_forceinline));
    break;
  }
  case OMPD_threadprivate:
  case OMPD_taskyield:
  case OMPD_barrier:
  case OMPD_taskwait:
  case OMPD_cancellation_point:
  case OMPD_cancel:
  case OMPD_flush:
  case OMPD_declare_reduction:
  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");
  }
}

int Sema::getOpenMPCaptureLevels(OpenMPDirectiveKind DKind) {
  SmallVector<OpenMPDirectiveKind, 4> CaptureRegions;
  getOpenMPCaptureRegions(CaptureRegions, DKind);
  return CaptureRegions.size();
}

static OMPCapturedExprDecl *buildCaptureDecl(Sema &S, IdentifierInfo *Id,
                                             Expr *CaptureExpr, bool WithInit,
                                             bool AsExpression) {
  assert(CaptureExpr);
  ASTContext &C = S.getASTContext();
  Expr *Init = AsExpression ? CaptureExpr : CaptureExpr->IgnoreImpCasts();
  QualType Ty = Init->getType();
  if (CaptureExpr->getObjectKind() == OK_Ordinary && CaptureExpr->isGLValue()) {
    if (S.getLangOpts().CPlusPlus) {
      Ty = C.getLValueReferenceType(Ty);
    } else {
      Ty = C.getPointerType(Ty);
      ExprResult Res =
          S.CreateBuiltinUnaryOp(CaptureExpr->getExprLoc(), UO_AddrOf, Init);
      if (!Res.isUsable())
        return nullptr;
      Init = Res.get();
    }
    WithInit = true;
  }
  auto *CED = OMPCapturedExprDecl::Create(C, S.CurContext, Id, Ty,
                                          CaptureExpr->getBeginLoc());
  if (!WithInit)
    CED->addAttr(OMPCaptureNoInitAttr::CreateImplicit(C));
  S.CurContext->addHiddenDecl(CED);
  S.AddInitializerToDecl(CED, Init, /*DirectInit=*/false);
  return CED;
}

static DeclRefExpr *buildCapture(Sema &S, ValueDecl *D, Expr *CaptureExpr,
                                 bool WithInit) {
  OMPCapturedExprDecl *CD;
  if (VarDecl *VD = S.isOpenMPCapturedDecl(D))
    CD = cast<OMPCapturedExprDecl>(VD);
  else
    CD = buildCaptureDecl(S, D->getIdentifier(), CaptureExpr, WithInit,
                          /*AsExpression=*/false);
  return buildDeclRefExpr(S, CD, CD->getType().getNonReferenceType(),
                          CaptureExpr->getExprLoc());
}

static ExprResult buildCapture(Sema &S, Expr *CaptureExpr, DeclRefExpr *&Ref) {
  CaptureExpr = S.DefaultLvalueConversion(CaptureExpr).get();
  if (!Ref) {
    OMPCapturedExprDecl *CD = buildCaptureDecl(
        S, &S.getASTContext().Idents.get(".capture_expr."), CaptureExpr,
        /*WithInit=*/true, /*AsExpression=*/true);
    Ref = buildDeclRefExpr(S, CD, CD->getType().getNonReferenceType(),
                           CaptureExpr->getExprLoc());
  }
  ExprResult Res = Ref;
  if (!S.getLangOpts().CPlusPlus &&
      CaptureExpr->getObjectKind() == OK_Ordinary && CaptureExpr->isGLValue() &&
      Ref->getType()->isPointerType()) {
    Res = S.CreateBuiltinUnaryOp(CaptureExpr->getExprLoc(), UO_Deref, Ref);
    if (!Res.isUsable())
      return ExprError();
  }
  return S.DefaultLvalueConversion(Res.get());
}

namespace {
// OpenMP directives parsed in this section are represented as a
// CapturedStatement with an associated statement.  If a syntax error
// is detected during the parsing of the associated statement, the
// compiler must abort processing and close the CapturedStatement.
//
// Combined directives such as 'target parallel' have more than one
// nested CapturedStatements.  This RAII ensures that we unwind out
// of all the nested CapturedStatements when an error is found.
class CaptureRegionUnwinderRAII {
private:
  Sema &S;
  bool &ErrorFound;
  OpenMPDirectiveKind DKind = OMPD_unknown;

public:
  CaptureRegionUnwinderRAII(Sema &S, bool &ErrorFound,
                            OpenMPDirectiveKind DKind)
      : S(S), ErrorFound(ErrorFound), DKind(DKind) {}
  ~CaptureRegionUnwinderRAII() {
    if (ErrorFound) {
      int ThisCaptureLevel = S.getOpenMPCaptureLevels(DKind);
      while (--ThisCaptureLevel >= 0)
        S.ActOnCapturedRegionError();
    }
  }
};
} // namespace

StmtResult Sema::ActOnOpenMPRegionEnd(StmtResult S,
                                      ArrayRef<OMPClause *> Clauses) {
  bool ErrorFound = false;
  CaptureRegionUnwinderRAII CaptureRegionUnwinder(
      *this, ErrorFound, DSAStack->getCurrentDirective());
  if (!S.isUsable()) {
    ErrorFound = true;
    return StmtError();
  }

  SmallVector<OpenMPDirectiveKind, 4> CaptureRegions;
  getOpenMPCaptureRegions(CaptureRegions, DSAStack->getCurrentDirective());
  OMPOrderedClause *OC = nullptr;
  OMPScheduleClause *SC = nullptr;
  SmallVector<const OMPLinearClause *, 4> LCs;
  SmallVector<const OMPClauseWithPreInit *, 4> PICs;
  // This is required for proper codegen.
  for (OMPClause *Clause : Clauses) {
    if (isOpenMPTaskingDirective(DSAStack->getCurrentDirective()) &&
        Clause->getClauseKind() == OMPC_in_reduction) {
      // Capture taskgroup task_reduction descriptors inside the tasking regions
      // with the corresponding in_reduction items.
      auto *IRC = cast<OMPInReductionClause>(Clause);
      for (Expr *E : IRC->taskgroup_descriptors())
        if (E)
          MarkDeclarationsReferencedInExpr(E);
    }
    if (isOpenMPPrivate(Clause->getClauseKind()) ||
        Clause->getClauseKind() == OMPC_copyprivate ||
        (getLangOpts().OpenMPUseTLS &&
         getASTContext().getTargetInfo().isTLSSupported() &&
         Clause->getClauseKind() == OMPC_copyin)) {
      DSAStack->setForceVarCapturing(Clause->getClauseKind() == OMPC_copyin);
      // Mark all variables in private list clauses as used in inner region.
      for (Stmt *VarRef : Clause->children()) {
        if (auto *E = cast_or_null<Expr>(VarRef)) {
          MarkDeclarationsReferencedInExpr(E);
        }
      }
      DSAStack->setForceVarCapturing(/*V=*/false);
    } else if (CaptureRegions.size() > 1 ||
               CaptureRegions.back() != OMPD_unknown) {
      if (auto *C = OMPClauseWithPreInit::get(Clause))
        PICs.push_back(C);
      if (auto *C = OMPClauseWithPostUpdate::get(Clause)) {
        if (Expr *E = C->getPostUpdateExpr())
          MarkDeclarationsReferencedInExpr(E);
      }
    }
    if (Clause->getClauseKind() == OMPC_schedule)
      SC = cast<OMPScheduleClause>(Clause);
    else if (Clause->getClauseKind() == OMPC_ordered)
      OC = cast<OMPOrderedClause>(Clause);
    else if (Clause->getClauseKind() == OMPC_linear)
      LCs.push_back(cast<OMPLinearClause>(Clause));
  }
  // OpenMP, 2.7.1 Loop Construct, Restrictions
  // The nonmonotonic modifier cannot be specified if an ordered clause is
  // specified.
  if (SC &&
      (SC->getFirstScheduleModifier() == OMPC_SCHEDULE_MODIFIER_nonmonotonic ||
       SC->getSecondScheduleModifier() ==
           OMPC_SCHEDULE_MODIFIER_nonmonotonic) &&
      OC) {
    Diag(SC->getFirstScheduleModifier() == OMPC_SCHEDULE_MODIFIER_nonmonotonic
             ? SC->getFirstScheduleModifierLoc()
             : SC->getSecondScheduleModifierLoc(),
         diag::err_omp_schedule_nonmonotonic_ordered)
        << SourceRange(OC->getBeginLoc(), OC->getEndLoc());
    ErrorFound = true;
  }
  if (!LCs.empty() && OC && OC->getNumForLoops()) {
    for (const OMPLinearClause *C : LCs) {
      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->getBeginLoc(), diag::err_omp_ordered_simd)
        << getOpenMPDirectiveName(DSAStack->getCurrentDirective());
    ErrorFound = true;
  }
  if (ErrorFound) {
    return StmtError();
  }
  StmtResult SR = S;
  for (OpenMPDirectiveKind ThisCaptureRegion : llvm::reverse(CaptureRegions)) {
    // Mark all variables in private list clauses as used in inner region.
    // Required for proper codegen of combined directives.
    // TODO: add processing for other clauses.
    if (ThisCaptureRegion != OMPD_unknown) {
      for (const clang::OMPClauseWithPreInit *C : PICs) {
        OpenMPDirectiveKind CaptureRegion = C->getCaptureRegion();
        // Find the particular capture region for the clause if the
        // directive is a combined one with multiple capture regions.
        // If the directive is not a combined one, the capture region
        // associated with the clause is OMPD_unknown and is generated
        // only once.
        if (CaptureRegion == ThisCaptureRegion ||
            CaptureRegion == OMPD_unknown) {
          if (auto *DS = cast_or_null<DeclStmt>(C->getPreInitStmt())) {
            for (Decl *D : DS->decls())
              MarkVariableReferenced(D->getLocation(), cast<VarDecl>(D));
          }
        }
      }
    }
    SR = ActOnCapturedRegionEnd(SR.get());
  }
  return SR;
}

static bool checkCancelRegion(Sema &SemaRef, OpenMPDirectiveKind CurrentRegion,
                              OpenMPDirectiveKind CancelRegion,
                              SourceLocation StartLoc) {
  // CancelRegion is only needed for cancel and cancellation_point.
  if (CurrentRegion != OMPD_cancel && CurrentRegion != OMPD_cancellation_point)
    return false;

  if (CancelRegion == OMPD_parallel || CancelRegion == OMPD_for ||
      CancelRegion == OMPD_sections || CancelRegion == OMPD_taskgroup)
    return false;

  SemaRef.Diag(StartLoc, diag::err_omp_wrong_cancel_region)
      << getOpenMPDirectiveName(CancelRegion);
  return true;
}

static bool checkNestingOfRegions(Sema &SemaRef, const DSAStackTy *Stack,
                                  OpenMPDirectiveKind CurrentRegion,
                                  const DeclarationNameInfo &CurrentName,
                                  OpenMPDirectiveKind CancelRegion,
                                  SourceLocation StartLoc) {
  if (Stack->getCurScope()) {
    OpenMPDirectiveKind ParentRegion = Stack->getParentDirective();
    OpenMPDirectiveKind OffendingRegion = ParentRegion;
    bool NestingProhibited = false;
    bool CloseNesting = true;
    bool OrphanSeen = false;
    enum {
      NoRecommend,
      ShouldBeInParallelRegion,
      ShouldBeInOrderedRegion,
      ShouldBeInTargetRegion,
      ShouldBeInTeamsRegion
    } Recommend = NoRecommend;
    if (isOpenMPSimdDirective(ParentRegion) && CurrentRegion != OMPD_ordered) {
      // OpenMP [2.16, Nesting of Regions]
      // OpenMP constructs may not be nested inside a simd region.
      // OpenMP [2.8.1,simd Construct, Restrictions]
      // An ordered construct with the simd clause is the only OpenMP
      // construct that can appear in the simd region.
      // Allowing a SIMD construct nested in another SIMD construct is an
      // extension. The OpenMP 4.5 spec does not allow it. Issue a warning
      // message.
      SemaRef.Diag(StartLoc, (CurrentRegion != OMPD_simd)
                                 ? diag::err_omp_prohibited_region_simd
                                 : diag::warn_omp_nesting_simd);
      return CurrentRegion != OMPD_simd;
    }
    if (ParentRegion == OMPD_atomic) {
      // OpenMP [2.16, Nesting of Regions]
      // OpenMP constructs may not be nested inside an atomic region.
      SemaRef.Diag(StartLoc, diag::err_omp_prohibited_region_atomic);
      return true;
    }
    if (CurrentRegion == OMPD_section) {
      // OpenMP [2.7.2, sections Construct, Restrictions]
      // Orphaned section directives are prohibited. That is, the section
      // directives must appear within the sections construct and must not be
      // encountered elsewhere in the sections region.
      if (ParentRegion != OMPD_sections &&
          ParentRegion != OMPD_parallel_sections) {
        SemaRef.Diag(StartLoc, diag::err_omp_orphaned_section_directive)
            << (ParentRegion != OMPD_unknown)
            << getOpenMPDirectiveName(ParentRegion);
        return true;
      }
      return false;
    }
    // Allow some constructs (except teams) to be orphaned (they could be
    // used in functions, called from OpenMP regions with the required
    // preconditions).
    if (ParentRegion == OMPD_unknown &&
        !isOpenMPNestingTeamsDirective(CurrentRegion))
      return false;
    if (CurrentRegion == OMPD_cancellation_point ||
        CurrentRegion == OMPD_cancel) {
      // OpenMP [2.16, Nesting of Regions]
      // A cancellation point construct for which construct-type-clause is
      // taskgroup must be nested inside a task construct. A cancellation
      // point construct for which construct-type-clause is not taskgroup must
      // be closely nested inside an OpenMP construct that matches the type
      // specified in construct-type-clause.
      // A cancel construct for which construct-type-clause is taskgroup must be
      // nested inside a task construct. A cancel construct for which
      // construct-type-clause is not taskgroup must be closely nested inside an
      // OpenMP construct that matches the type specified in
      // construct-type-clause.
      NestingProhibited =
          !((CancelRegion == OMPD_parallel &&
             (ParentRegion == OMPD_parallel ||
              ParentRegion == OMPD_target_parallel)) ||
            (CancelRegion == OMPD_for &&
             (ParentRegion == OMPD_for || ParentRegion == OMPD_parallel_for ||
              ParentRegion == OMPD_target_parallel_for ||
              ParentRegion == OMPD_distribute_parallel_for ||
              ParentRegion == OMPD_teams_distribute_parallel_for ||
              ParentRegion == OMPD_target_teams_distribute_parallel_for)) ||
            (CancelRegion == OMPD_taskgroup && ParentRegion == OMPD_task) ||
            (CancelRegion == OMPD_sections &&
             (ParentRegion == OMPD_section || ParentRegion == OMPD_sections ||
              ParentRegion == OMPD_parallel_sections)));
    } else if (CurrentRegion == OMPD_master) {
      // OpenMP [2.16, Nesting of Regions]
      // A master region may not be closely nested inside a worksharing,
      // atomic, or explicit task region.
      NestingProhibited = isOpenMPWorksharingDirective(ParentRegion) ||
                          isOpenMPTaskingDirective(ParentRegion);
    } else if (CurrentRegion == OMPD_critical && CurrentName.getName()) {
      // OpenMP [2.16, Nesting of Regions]
      // A critical region may not be nested (closely or otherwise) inside a
      // critical region with the same name. Note that this restriction is not
      // sufficient to prevent deadlock.
      SourceLocation PreviousCriticalLoc;
      bool DeadLock = Stack->hasDirective(
          [CurrentName, &PreviousCriticalLoc](OpenMPDirectiveKind K,
                                              const DeclarationNameInfo &DNI,
                                              SourceLocation Loc) {
            if (K == OMPD_critical && DNI.getName() == CurrentName.getName()) {
              PreviousCriticalLoc = Loc;
              return true;
            }
            return false;
          },
          false /* skip top directive */);
      if (DeadLock) {
        SemaRef.Diag(StartLoc,
                     diag::err_omp_prohibited_region_critical_same_name)
            << CurrentName.getName();
        if (PreviousCriticalLoc.isValid())
          SemaRef.Diag(PreviousCriticalLoc,
                       diag::note_omp_previous_critical_region);
        return true;
      }
    } else if (CurrentRegion == OMPD_barrier) {
      // OpenMP [2.16, Nesting of Regions]
      // A barrier region may not be closely nested inside a worksharing,
      // explicit task, critical, ordered, atomic, or master region.
      NestingProhibited = isOpenMPWorksharingDirective(ParentRegion) ||
                          isOpenMPTaskingDirective(ParentRegion) ||
                          ParentRegion == OMPD_master ||
                          ParentRegion == OMPD_critical ||
                          ParentRegion == OMPD_ordered;
    } else if (isOpenMPWorksharingDirective(CurrentRegion) &&
               !isOpenMPParallelDirective(CurrentRegion) &&
               !isOpenMPTeamsDirective(CurrentRegion)) {
      // OpenMP [2.16, Nesting of Regions]
      // A worksharing region may not be closely nested inside a worksharing,
      // explicit task, critical, ordered, atomic, or master region.
      NestingProhibited = isOpenMPWorksharingDirective(ParentRegion) ||
                          isOpenMPTaskingDirective(ParentRegion) ||
                          ParentRegion == OMPD_master ||
                          ParentRegion == OMPD_critical ||
                          ParentRegion == OMPD_ordered;
      Recommend = ShouldBeInParallelRegion;
    } else if (CurrentRegion == OMPD_ordered) {
      // OpenMP [2.16, Nesting of Regions]
      // An ordered region may not be closely nested inside a critical,
      // atomic, or explicit task region.
      // An ordered region must be closely nested inside a loop region (or
      // parallel loop region) with an ordered clause.
      // OpenMP [2.8.1,simd Construct, Restrictions]
      // An ordered construct with the simd clause is the only OpenMP construct
      // that can appear in the simd region.
      NestingProhibited = ParentRegion == OMPD_critical ||
                          isOpenMPTaskingDirective(ParentRegion) ||
                          !(isOpenMPSimdDirective(ParentRegion) ||
                            Stack->isParentOrderedRegion());
      Recommend = ShouldBeInOrderedRegion;
    } else if (isOpenMPNestingTeamsDirective(CurrentRegion)) {
      // OpenMP [2.16, Nesting of Regions]
      // If specified, a teams construct must be contained within a target
      // construct.
      NestingProhibited = ParentRegion != OMPD_target;
      OrphanSeen = ParentRegion == OMPD_unknown;
      Recommend = ShouldBeInTargetRegion;
    }
    if (!NestingProhibited &&
        !isOpenMPTargetExecutionDirective(CurrentRegion) &&
        !isOpenMPTargetDataManagementDirective(CurrentRegion) &&
        (ParentRegion == OMPD_teams || ParentRegion == OMPD_target_teams)) {
      // OpenMP [2.16, Nesting of Regions]
      // distribute, parallel, parallel sections, parallel workshare, and the
      // parallel loop and parallel loop SIMD constructs are the only OpenMP
      // constructs that can be closely nested in the teams region.
      NestingProhibited = !isOpenMPParallelDirective(CurrentRegion) &&
                          !isOpenMPDistributeDirective(CurrentRegion);
      Recommend = ShouldBeInParallelRegion;
    }
    if (!NestingProhibited &&
        isOpenMPNestingDistributeDirective(CurrentRegion)) {
      // OpenMP 4.5 [2.17 Nesting of Regions]
      // The region associated with the distribute construct must be strictly
      // nested inside a teams region
      NestingProhibited =
          (ParentRegion != OMPD_teams && ParentRegion != OMPD_target_teams);
      Recommend = ShouldBeInTeamsRegion;
    }
    if (!NestingProhibited &&
        (isOpenMPTargetExecutionDirective(CurrentRegion) ||
         isOpenMPTargetDataManagementDirective(CurrentRegion))) {
      // OpenMP 4.5 [2.17 Nesting of Regions]
      // If a target, target update, target data, target enter data, or
      // target exit data construct is encountered during execution of a
      // target region, the behavior is unspecified.
      NestingProhibited = Stack->hasDirective(
          [&OffendingRegion](OpenMPDirectiveKind K, const DeclarationNameInfo &,
                             SourceLocation) {
            if (isOpenMPTargetExecutionDirective(K)) {
              OffendingRegion = K;
              return true;
            }
            return false;
          },
          false /* don't skip top directive */);
      CloseNesting = false;
    }
    if (NestingProhibited) {
      if (OrphanSeen) {
        SemaRef.Diag(StartLoc, diag::err_omp_orphaned_device_directive)
            << getOpenMPDirectiveName(CurrentRegion) << Recommend;
      } else {
        SemaRef.Diag(StartLoc, diag::err_omp_prohibited_region)
            << CloseNesting << getOpenMPDirectiveName(OffendingRegion)
            << Recommend << getOpenMPDirectiveName(CurrentRegion);
      }
      return true;
    }
  }
  return false;
}

static bool checkIfClauses(Sema &S, OpenMPDirectiveKind Kind,
                           ArrayRef<OMPClause *> Clauses,
                           ArrayRef<OpenMPDirectiveKind> AllowedNameModifiers) {
  bool ErrorFound = false;
  unsigned NamedModifiersNumber = 0;
  SmallVector<const OMPIfClause *, OMPC_unknown + 1> FoundNameModifiers(
      OMPD_unknown + 1);
  SmallVector<SourceLocation, 4> NameModifierLoc;
  for (const OMPClause *C : Clauses) {
    if (const auto *IC = dyn_cast_or_null<OMPIfClause>(C)) {
      // At most one if clause without a directive-name-modifier can appear on
      // the directive.
      OpenMPDirectiveKind CurNM = IC->getNameModifier();
      if (FoundNameModifiers[CurNM]) {
        S.Diag(C->getBeginLoc(), diag::err_omp_more_one_clause)
            << getOpenMPDirectiveName(Kind) << getOpenMPClauseName(OMPC_if)
            << (CurNM != OMPD_unknown) << getOpenMPDirectiveName(CurNM);
        ErrorFound = true;
      } else if (CurNM != OMPD_unknown) {
        NameModifierLoc.push_back(IC->getNameModifierLoc());
        ++NamedModifiersNumber;
      }
      FoundNameModifiers[CurNM] = IC;
      if (CurNM == OMPD_unknown)
        continue;
      // Check if the specified name modifier is allowed for the current
      // directive.
      // At most one if clause with the particular directive-name-modifier can
      // appear on the directive.
      bool MatchFound = false;
      for (auto NM : AllowedNameModifiers) {
        if (CurNM == NM) {
          MatchFound = true;
          break;
        }
      }
      if (!MatchFound) {
        S.Diag(IC->getNameModifierLoc(),
               diag::err_omp_wrong_if_directive_name_modifier)
            << getOpenMPDirectiveName(CurNM) << getOpenMPDirectiveName(Kind);
        ErrorFound = true;
      }
    }
  }
  // If any if clause on the directive includes a directive-name-modifier then
  // 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]->getBeginLoc(),
             diag::err_omp_no_more_if_clause);
    } else {
      std::string Values;
      std::string Sep(", ");
      unsigned AllowedCnt = 0;
      unsigned TotalAllowedNum =
          AllowedNameModifiers.size() - NamedModifiersNumber;
      for (unsigned Cnt = 0, End = AllowedNameModifiers.size(); Cnt < End;
           ++Cnt) {
        OpenMPDirectiveKind NM = AllowedNameModifiers[Cnt];
        if (!FoundNameModifiers[NM]) {
          Values += "'";
          Values += getOpenMPDirectiveName(NM);
          Values += "'";
          if (AllowedCnt + 2 == TotalAllowedNum)
            Values += " or ";
          else if (AllowedCnt + 1 != TotalAllowedNum)
            Values += Sep;
          ++AllowedCnt;
        }
      }
      S.Diag(FoundNameModifiers[OMPD_unknown]->getCondition()->getBeginLoc(),
             diag::err_omp_unnamed_if_clause)
          << (TotalAllowedNum > 1) << Values;
    }
    for (SourceLocation Loc : NameModifierLoc) {
      S.Diag(Loc, diag::note_omp_previous_named_if_clause);
    }
    ErrorFound = true;
  }
  return ErrorFound;
}

StmtResult Sema::ActOnOpenMPExecutableDirective(
    OpenMPDirectiveKind Kind, const DeclarationNameInfo &DirName,
    OpenMPDirectiveKind CancelRegion, ArrayRef<OMPClause *> Clauses,
    Stmt *AStmt, SourceLocation StartLoc, SourceLocation EndLoc) {
  StmtResult Res = StmtError();
  // First check CancelRegion which is then used in checkNestingOfRegions.
  if (checkCancelRegion(*this, Kind, CancelRegion, StartLoc) ||
      checkNestingOfRegions(*this, DSAStack, Kind, DirName, CancelRegion,
                            StartLoc))
    return StmtError();

  llvm::SmallVector<OMPClause *, 8> ClausesWithImplicit;
  VarsWithInheritedDSAType VarsWithInheritedDSA;
  bool ErrorFound = false;
  ClausesWithImplicit.append(Clauses.begin(), Clauses.end());
  if (AStmt && !CurContext->isDependentContext()) {
    assert(isa<CapturedStmt>(AStmt) && "Captured statement expected");

    // Check default data sharing attributes for referenced variables.
    DSAAttrChecker DSAChecker(DSAStack, *this, cast<CapturedStmt>(AStmt));
    int ThisCaptureLevel = getOpenMPCaptureLevels(Kind);
    Stmt *S = AStmt;
    while (--ThisCaptureLevel >= 0)
      S = cast<CapturedStmt>(S)->getCapturedStmt();
    DSAChecker.Visit(S);
    if (DSAChecker.isErrorFound())
      return StmtError();
    // Generate list of implicitly defined firstprivate variables.
    VarsWithInheritedDSA = DSAChecker.getVarsWithInheritedDSA();

    SmallVector<Expr *, 4> ImplicitFirstprivates(
        DSAChecker.getImplicitFirstprivate().begin(),
        DSAChecker.getImplicitFirstprivate().end());
    SmallVector<Expr *, 4> ImplicitMaps(DSAChecker.getImplicitMap().begin(),
                                        DSAChecker.getImplicitMap().end());
    // Mark taskgroup task_reduction descriptors as implicitly firstprivate.
    for (OMPClause *C : Clauses) {
      if (auto *IRC = dyn_cast<OMPInReductionClause>(C)) {
        for (Expr *E : IRC->taskgroup_descriptors())
          if (E)
            ImplicitFirstprivates.emplace_back(E);
      }
    }
    if (!ImplicitFirstprivates.empty()) {
      if (OMPClause *Implicit = ActOnOpenMPFirstprivateClause(
              ImplicitFirstprivates, SourceLocation(), SourceLocation(),
              SourceLocation())) {
        ClausesWithImplicit.push_back(Implicit);
        ErrorFound = cast<OMPFirstprivateClause>(Implicit)->varlist_size() !=
                     ImplicitFirstprivates.size();
      } else {
        ErrorFound = true;
      }
    }
    if (!ImplicitMaps.empty()) {
      if (OMPClause *Implicit = ActOnOpenMPMapClause(
              OMPC_MAP_unknown, OMPC_MAP_tofrom, /*IsMapTypeImplicit=*/true,
              SourceLocation(), SourceLocation(), ImplicitMaps,
              SourceLocation(), SourceLocation(), SourceLocation())) {
        ClausesWithImplicit.emplace_back(Implicit);
        ErrorFound |=
            cast<OMPMapClause>(Implicit)->varlist_size() != ImplicitMaps.size();
      } else {
        ErrorFound = true;
      }
    }
  }

  llvm::SmallVector<OpenMPDirectiveKind, 4> AllowedNameModifiers;
  switch (Kind) {
  case OMPD_parallel:
    Res = ActOnOpenMPParallelDirective(ClausesWithImplicit, AStmt, StartLoc,
                                       EndLoc);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_simd:
    Res = ActOnOpenMPSimdDirective(ClausesWithImplicit, AStmt, StartLoc, EndLoc,
                                   VarsWithInheritedDSA);
    break;
  case OMPD_for:
    Res = ActOnOpenMPForDirective(ClausesWithImplicit, AStmt, StartLoc, EndLoc,
                                  VarsWithInheritedDSA);
    break;
  case OMPD_for_simd:
    Res = ActOnOpenMPForSimdDirective(ClausesWithImplicit, AStmt, StartLoc,
                                      EndLoc, VarsWithInheritedDSA);
    break;
  case OMPD_sections:
    Res = ActOnOpenMPSectionsDirective(ClausesWithImplicit, AStmt, StartLoc,
                                       EndLoc);
    break;
  case OMPD_section:
    assert(ClausesWithImplicit.empty() &&
           "No clauses are allowed for 'omp section' directive");
    Res = ActOnOpenMPSectionDirective(AStmt, StartLoc, EndLoc);
    break;
  case OMPD_single:
    Res = ActOnOpenMPSingleDirective(ClausesWithImplicit, AStmt, StartLoc,
                                     EndLoc);
    break;
  case OMPD_master:
    assert(ClausesWithImplicit.empty() &&
           "No clauses are allowed for 'omp master' directive");
    Res = ActOnOpenMPMasterDirective(AStmt, StartLoc, EndLoc);
    break;
  case OMPD_critical:
    Res = ActOnOpenMPCriticalDirective(DirName, ClausesWithImplicit, AStmt,
                                       StartLoc, EndLoc);
    break;
  case OMPD_parallel_for:
    Res = ActOnOpenMPParallelForDirective(ClausesWithImplicit, AStmt, StartLoc,
                                          EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_parallel_for_simd:
    Res = ActOnOpenMPParallelForSimdDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_parallel_sections:
    Res = ActOnOpenMPParallelSectionsDirective(ClausesWithImplicit, AStmt,
                                               StartLoc, EndLoc);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_task:
    Res =
        ActOnOpenMPTaskDirective(ClausesWithImplicit, AStmt, StartLoc, EndLoc);
    AllowedNameModifiers.push_back(OMPD_task);
    break;
  case OMPD_taskyield:
    assert(ClausesWithImplicit.empty() &&
           "No clauses are allowed for 'omp taskyield' directive");
    assert(AStmt == nullptr &&
           "No associated statement allowed for 'omp taskyield' directive");
    Res = ActOnOpenMPTaskyieldDirective(StartLoc, EndLoc);
    break;
  case OMPD_barrier:
    assert(ClausesWithImplicit.empty() &&
           "No clauses are allowed for 'omp barrier' directive");
    assert(AStmt == nullptr &&
           "No associated statement allowed for 'omp barrier' directive");
    Res = ActOnOpenMPBarrierDirective(StartLoc, EndLoc);
    break;
  case OMPD_taskwait:
    assert(ClausesWithImplicit.empty() &&
           "No clauses are allowed for 'omp taskwait' directive");
    assert(AStmt == nullptr &&
           "No associated statement allowed for 'omp taskwait' directive");
    Res = ActOnOpenMPTaskwaitDirective(StartLoc, EndLoc);
    break;
  case OMPD_taskgroup:
    Res = ActOnOpenMPTaskgroupDirective(ClausesWithImplicit, AStmt, StartLoc,
                                        EndLoc);
    break;
  case OMPD_flush:
    assert(AStmt == nullptr &&
           "No associated statement allowed for 'omp flush' directive");
    Res = ActOnOpenMPFlushDirective(ClausesWithImplicit, StartLoc, EndLoc);
    break;
  case OMPD_ordered:
    Res = ActOnOpenMPOrderedDirective(ClausesWithImplicit, AStmt, StartLoc,
                                      EndLoc);
    break;
  case OMPD_atomic:
    Res = ActOnOpenMPAtomicDirective(ClausesWithImplicit, AStmt, StartLoc,
                                     EndLoc);
    break;
  case OMPD_teams:
    Res =
        ActOnOpenMPTeamsDirective(ClausesWithImplicit, AStmt, StartLoc, EndLoc);
    break;
  case OMPD_target:
    Res = ActOnOpenMPTargetDirective(ClausesWithImplicit, AStmt, StartLoc,
                                     EndLoc);
    AllowedNameModifiers.push_back(OMPD_target);
    break;
  case OMPD_target_parallel:
    Res = ActOnOpenMPTargetParallelDirective(ClausesWithImplicit, AStmt,
                                             StartLoc, EndLoc);
    AllowedNameModifiers.push_back(OMPD_target);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_target_parallel_for:
    Res = ActOnOpenMPTargetParallelForDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_target);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_cancellation_point:
    assert(ClausesWithImplicit.empty() &&
           "No clauses are allowed for 'omp cancellation point' directive");
    assert(AStmt == nullptr && "No associated statement allowed for 'omp "
                               "cancellation point' directive");
    Res = ActOnOpenMPCancellationPointDirective(StartLoc, EndLoc, CancelRegion);
    break;
  case OMPD_cancel:
    assert(AStmt == nullptr &&
           "No associated statement allowed for 'omp cancel' directive");
    Res = ActOnOpenMPCancelDirective(ClausesWithImplicit, StartLoc, EndLoc,
                                     CancelRegion);
    AllowedNameModifiers.push_back(OMPD_cancel);
    break;
  case OMPD_target_data:
    Res = ActOnOpenMPTargetDataDirective(ClausesWithImplicit, AStmt, StartLoc,
                                         EndLoc);
    AllowedNameModifiers.push_back(OMPD_target_data);
    break;
  case OMPD_target_enter_data:
    Res = ActOnOpenMPTargetEnterDataDirective(ClausesWithImplicit, StartLoc,
                                              EndLoc, AStmt);
    AllowedNameModifiers.push_back(OMPD_target_enter_data);
    break;
  case OMPD_target_exit_data:
    Res = ActOnOpenMPTargetExitDataDirective(ClausesWithImplicit, StartLoc,
                                             EndLoc, AStmt);
    AllowedNameModifiers.push_back(OMPD_target_exit_data);
    break;
  case OMPD_taskloop:
    Res = ActOnOpenMPTaskLoopDirective(ClausesWithImplicit, AStmt, StartLoc,
                                       EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_taskloop);
    break;
  case OMPD_taskloop_simd:
    Res = ActOnOpenMPTaskLoopSimdDirective(ClausesWithImplicit, AStmt, StartLoc,
                                           EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_taskloop);
    break;
  case OMPD_distribute:
    Res = ActOnOpenMPDistributeDirective(ClausesWithImplicit, AStmt, StartLoc,
                                         EndLoc, VarsWithInheritedDSA);
    break;
  case OMPD_target_update:
    Res = ActOnOpenMPTargetUpdateDirective(ClausesWithImplicit, StartLoc,
                                           EndLoc, AStmt);
    AllowedNameModifiers.push_back(OMPD_target_update);
    break;
  case OMPD_distribute_parallel_for:
    Res = ActOnOpenMPDistributeParallelForDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_distribute_parallel_for_simd:
    Res = ActOnOpenMPDistributeParallelForSimdDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_distribute_simd:
    Res = ActOnOpenMPDistributeSimdDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    break;
  case OMPD_target_parallel_for_simd:
    Res = ActOnOpenMPTargetParallelForSimdDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_target);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_target_simd:
    Res = ActOnOpenMPTargetSimdDirective(ClausesWithImplicit, AStmt, StartLoc,
                                         EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_target);
    break;
  case OMPD_teams_distribute:
    Res = ActOnOpenMPTeamsDistributeDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    break;
  case OMPD_teams_distribute_simd:
    Res = ActOnOpenMPTeamsDistributeSimdDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    break;
  case OMPD_teams_distribute_parallel_for_simd:
    Res = ActOnOpenMPTeamsDistributeParallelForSimdDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_teams_distribute_parallel_for:
    Res = ActOnOpenMPTeamsDistributeParallelForDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_target_teams:
    Res = ActOnOpenMPTargetTeamsDirective(ClausesWithImplicit, AStmt, StartLoc,
                                          EndLoc);
    AllowedNameModifiers.push_back(OMPD_target);
    break;
  case OMPD_target_teams_distribute:
    Res = ActOnOpenMPTargetTeamsDistributeDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_target);
    break;
  case OMPD_target_teams_distribute_parallel_for:
    Res = ActOnOpenMPTargetTeamsDistributeParallelForDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_target);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_target_teams_distribute_parallel_for_simd:
    Res = ActOnOpenMPTargetTeamsDistributeParallelForSimdDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_target);
    AllowedNameModifiers.push_back(OMPD_parallel);
    break;
  case OMPD_target_teams_distribute_simd:
    Res = ActOnOpenMPTargetTeamsDistributeSimdDirective(
        ClausesWithImplicit, AStmt, StartLoc, EndLoc, VarsWithInheritedDSA);
    AllowedNameModifiers.push_back(OMPD_target);
    break;
  case OMPD_declare_target:
  case OMPD_end_declare_target:
  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");
  }

  for (const auto &P : VarsWithInheritedDSA) {
    Diag(P.second->getExprLoc(), diag::err_omp_no_dsa_for_variable)
        << P.first << P.second->getSourceRange();
  }
  ErrorFound = !VarsWithInheritedDSA.empty() || ErrorFound;

  if (!AllowedNameModifiers.empty())
    ErrorFound = checkIfClauses(*this, Kind, Clauses, AllowedNameModifiers) ||
                 ErrorFound;

  if (ErrorFound)
    return StmtError();
  return Res;
}

Sema::DeclGroupPtrTy Sema::ActOnOpenMPDeclareSimdDirective(
    DeclGroupPtrTy DG, OMPDeclareSimdDeclAttr::BranchStateTy BS, Expr *Simdlen,
    ArrayRef<Expr *> Uniforms, ArrayRef<Expr *> Aligneds,
    ArrayRef<Expr *> Alignments, ArrayRef<Expr *> Linears,
    ArrayRef<unsigned> LinModifiers, ArrayRef<Expr *> Steps, SourceRange SR) {
  assert(Aligneds.size() == Alignments.size());
  assert(Linears.size() == LinModifiers.size());
  assert(Linears.size() == Steps.size());
  if (!DG || DG.get().isNull())
    return DeclGroupPtrTy();

  if (!DG.get().isSingleDecl()) {
    Diag(SR.getBegin(), diag::err_omp_single_decl_in_declare_simd);
    return DG;
  }
  Decl *ADecl = DG.get().getSingleDecl();
  if (auto *FTD = dyn_cast<FunctionTemplateDecl>(ADecl))
    ADecl = FTD->getTemplatedDecl();

  auto *FD = dyn_cast<FunctionDecl>(ADecl);
  if (!FD) {
    Diag(ADecl->getLocation(), diag::err_omp_function_expected);
    return DeclGroupPtrTy();
  }

  // OpenMP [2.8.2, declare simd construct, Description]
  // The parameter of the simdlen clause must be a constant positive integer
  // expression.
  ExprResult SL;
  if (Simdlen)
    SL = VerifyPositiveIntegerConstantInClause(Simdlen, OMPC_simdlen);
  // OpenMP [2.8.2, declare simd construct, Description]
  // The special this pointer can be used as if was one of the arguments to the
  // function in any of the linear, aligned, or uniform clauses.
  // The uniform clause declares one or more arguments to have an invariant
  // value for all concurrent invocations of the function in the execution of a
  // single SIMD loop.
  llvm::DenseMap<const Decl *, const Expr *> UniformedArgs;
  const Expr *UniformedLinearThis = nullptr;
  for (const Expr *E : Uniforms) {
    E = E->IgnoreParenImpCasts();
    if (const auto *DRE = dyn_cast<DeclRefExpr>(E))
      if (const auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl()))
        if (FD->getNumParams() > PVD->getFunctionScopeIndex() &&
            FD->getParamDecl(PVD->getFunctionScopeIndex())
                    ->getCanonicalDecl() == PVD->getCanonicalDecl()) {
          UniformedArgs.try_emplace(PVD->getCanonicalDecl(), E);
          continue;
        }
    if (isa<CXXThisExpr>(E)) {
      UniformedLinearThis = E;
      continue;
    }
    Diag(E->getExprLoc(), diag::err_omp_param_or_this_in_clause)
        << FD->getDeclName() << (isa<CXXMethodDecl>(ADecl) ? 1 : 0);
  }
  // OpenMP [2.8.2, declare simd construct, Description]
  // The aligned clause declares that the object to which each list item points
  // is aligned to the number of bytes expressed in the optional parameter of
  // the aligned clause.
  // The special this pointer can be used as if was one of the arguments to the
  // function in any of the linear, aligned, or uniform clauses.
  // The type of list items appearing in the aligned clause must be array,
  // pointer, reference to array, or reference to pointer.
  llvm::DenseMap<const Decl *, const Expr *> AlignedArgs;
  const Expr *AlignedThis = nullptr;
  for (const Expr *E : Aligneds) {
    E = E->IgnoreParenImpCasts();
    if (const auto *DRE = dyn_cast<DeclRefExpr>(E))
      if (const auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
        const VarDecl *CanonPVD = PVD->getCanonicalDecl();
        if (FD->getNumParams() > PVD->getFunctionScopeIndex() &&
            FD->getParamDecl(PVD->getFunctionScopeIndex())
                    ->getCanonicalDecl() == CanonPVD) {
          // OpenMP  [2.8.1, simd construct, Restrictions]
          // A list-item cannot appear in more than one aligned clause.
          if (AlignedArgs.count(CanonPVD) > 0) {
            Diag(E->getExprLoc(), diag::err_omp_aligned_twice)
                << 1 << E->getSourceRange();
            Diag(AlignedArgs[CanonPVD]->getExprLoc(),
                 diag::note_omp_explicit_dsa)
                << getOpenMPClauseName(OMPC_aligned);
            continue;
          }
          AlignedArgs[CanonPVD] = E;
          QualType QTy = PVD->getType()
                             .getNonReferenceType()
                             .getUnqualifiedType()
                             .getCanonicalType();
          const Type *Ty = QTy.getTypePtrOrNull();
          if (!Ty || (!Ty->isArrayType() && !Ty->isPointerType())) {
            Diag(E->getExprLoc(), diag::err_omp_aligned_expected_array_or_ptr)
                << QTy << getLangOpts().CPlusPlus << E->getSourceRange();
            Diag(PVD->getLocation(), diag::note_previous_decl) << PVD;
          }
          continue;
        }
      }
    if (isa<CXXThisExpr>(E)) {
      if (AlignedThis) {
        Diag(E->getExprLoc(), diag::err_omp_aligned_twice)
            << 2 << E->getSourceRange();
        Diag(AlignedThis->getExprLoc(), diag::note_omp_explicit_dsa)
            << getOpenMPClauseName(OMPC_aligned);
      }
      AlignedThis = E;
      continue;
    }
    Diag(E->getExprLoc(), diag::err_omp_param_or_this_in_clause)
        << FD->getDeclName() << (isa<CXXMethodDecl>(ADecl) ? 1 : 0);
  }
  // The optional parameter of the aligned clause, alignment, must be a constant
  // positive integer expression. If no optional parameter is specified,
  // implementation-defined default alignments for SIMD instructions on the
  // target platforms are assumed.
  SmallVector<const Expr *, 4> NewAligns;
  for (Expr *E : Alignments) {
    ExprResult Align;
    if (E)
      Align = VerifyPositiveIntegerConstantInClause(E, OMPC_aligned);
    NewAligns.push_back(Align.get());
  }
  // OpenMP [2.8.2, declare simd construct, Description]
  // The linear clause declares one or more list items to be private to a SIMD
  // lane and to have a linear relationship with respect to the iteration space
  // of a loop.
  // The special this pointer can be used as if was one of the arguments to the
  // function in any of the linear, aligned, or uniform clauses.
  // When a linear-step expression is specified in a linear clause it must be
  // either a constant integer expression or an integer-typed parameter that is
  // specified in a uniform clause on the directive.
  llvm::DenseMap<const Decl *, const Expr *> LinearArgs;
  const bool IsUniformedThis = UniformedLinearThis != nullptr;
  auto MI = LinModifiers.begin();
  for (const Expr *E : Linears) {
    auto LinKind = static_cast<OpenMPLinearClauseKind>(*MI);
    ++MI;
    E = E->IgnoreParenImpCasts();
    if (const auto *DRE = dyn_cast<DeclRefExpr>(E))
      if (const auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
        const VarDecl *CanonPVD = PVD->getCanonicalDecl();
        if (FD->getNumParams() > PVD->getFunctionScopeIndex() &&
            FD->getParamDecl(PVD->getFunctionScopeIndex())
                    ->getCanonicalDecl() == CanonPVD) {
          // OpenMP  [2.15.3.7, linear Clause, Restrictions]
          // A list-item cannot appear in more than one linear clause.
          if (LinearArgs.count(CanonPVD) > 0) {
            Diag(E->getExprLoc(), diag::err_omp_wrong_dsa)
                << getOpenMPClauseName(OMPC_linear)
                << getOpenMPClauseName(OMPC_linear) << E->getSourceRange();
            Diag(LinearArgs[CanonPVD]->getExprLoc(),
                 diag::note_omp_explicit_dsa)
                << getOpenMPClauseName(OMPC_linear);
            continue;
          }
          // Each argument can appear in at most one uniform or linear clause.
          if (UniformedArgs.count(CanonPVD) > 0) {
            Diag(E->getExprLoc(), diag::err_omp_wrong_dsa)
                << getOpenMPClauseName(OMPC_linear)
                << getOpenMPClauseName(OMPC_uniform) << E->getSourceRange();
            Diag(UniformedArgs[CanonPVD]->getExprLoc(),
                 diag::note_omp_explicit_dsa)
                << getOpenMPClauseName(OMPC_uniform);
            continue;
          }
          LinearArgs[CanonPVD] = E;
          if (E->isValueDependent() || E->isTypeDependent() ||
              E->isInstantiationDependent() ||
              E->containsUnexpandedParameterPack())
            continue;
          (void)CheckOpenMPLinearDecl(CanonPVD, E->getExprLoc(), LinKind,
                                      PVD->getOriginalType());
          continue;
        }
      }
    if (isa<CXXThisExpr>(E)) {
      if (UniformedLinearThis) {
        Diag(E->getExprLoc(), diag::err_omp_wrong_dsa)
            << getOpenMPClauseName(OMPC_linear)
            << getOpenMPClauseName(IsUniformedThis ? OMPC_uniform : OMPC_linear)
            << E->getSourceRange();
        Diag(UniformedLinearThis->getExprLoc(), diag::note_omp_explicit_dsa)
            << getOpenMPClauseName(IsUniformedThis ? OMPC_uniform
                                                   : OMPC_linear);
        continue;
      }
      UniformedLinearThis = E;
      if (E->isValueDependent() || E->isTypeDependent() ||
          E->isInstantiationDependent() || E->containsUnexpandedParameterPack())
        continue;
      (void)CheckOpenMPLinearDecl(/*D=*/nullptr, E->getExprLoc(), LinKind,
                                  E->getType());
      continue;
    }
    Diag(E->getExprLoc(), diag::err_omp_param_or_this_in_clause)
        << FD->getDeclName() << (isa<CXXMethodDecl>(ADecl) ? 1 : 0);
  }
  Expr *Step = nullptr;
  Expr *NewStep = nullptr;
  SmallVector<Expr *, 4> NewSteps;
  for (Expr *E : Steps) {
    // Skip the same step expression, it was checked already.
    if (Step == E || !E) {
      NewSteps.push_back(E ? NewStep : nullptr);
      continue;
    }
    Step = E;
    if (const auto *DRE = dyn_cast<DeclRefExpr>(Step))
      if (const auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
        const VarDecl *CanonPVD = PVD->getCanonicalDecl();
        if (UniformedArgs.count(CanonPVD) == 0) {
          Diag(Step->getExprLoc(), diag::err_omp_expected_uniform_param)
              << Step->getSourceRange();
        } else if (E->isValueDependent() || E->isTypeDependent() ||
                   E->isInstantiationDependent() ||
                   E->containsUnexpandedParameterPack() ||
                   CanonPVD->getType()->hasIntegerRepresentation()) {
          NewSteps.push_back(Step);
        } else {
          Diag(Step->getExprLoc(), diag::err_omp_expected_int_param)
              << Step->getSourceRange();
        }
        continue;
      }
    NewStep = Step;
    if (Step && !Step->isValueDependent() && !Step->isTypeDependent() &&
        !Step->isInstantiationDependent() &&
        !Step->containsUnexpandedParameterPack()) {
      NewStep = PerformOpenMPImplicitIntegerConversion(Step->getExprLoc(), Step)
                    .get();
      if (NewStep)
        NewStep = VerifyIntegerConstantExpression(NewStep).get();
    }
    NewSteps.push_back(NewStep);
  }
  auto *NewAttr = OMPDeclareSimdDeclAttr::CreateImplicit(
      Context, BS, SL.get(), const_cast<Expr **>(Uniforms.data()),
      Uniforms.size(), const_cast<Expr **>(Aligneds.data()), Aligneds.size(),
      const_cast<Expr **>(NewAligns.data()), NewAligns.size(),
      const_cast<Expr **>(Linears.data()), Linears.size(),
      const_cast<unsigned *>(LinModifiers.data()), LinModifiers.size(),
      NewSteps.data(), NewSteps.size(), SR);
  ADecl->addAttr(NewAttr);
  return ConvertDeclToDeclGroup(ADecl);
}

StmtResult Sema::ActOnOpenMPParallelDirective(ArrayRef<OMPClause *> Clauses,
                                              Stmt *AStmt,
                                              SourceLocation StartLoc,
                                              SourceLocation EndLoc) {
  if (!AStmt)
    return StmtError();

  auto *CS = cast<CapturedStmt>(AStmt);
  // 1.2.2 OpenMP Language Terminology
  // Structured block - An executable statement with a single entry at the
  // top and a single exit at the bottom.
  // The point of exit cannot be a branch out of the structured block.
  // longjmp() and throw() must not violate the entry/exit criteria.
  CS->getCapturedDecl()->setNothrow();

  setFunctionHasBranchProtectedScope();

  return OMPParallelDirective::Create(Context, StartLoc, EndLoc, Clauses, AStmt,
                                      DSAStack->isCancelRegion());
}

namespace {
/// Helper class for checking canonical form of the OpenMP loops and
/// extracting iteration space of each loop in the loop nest, that will be used
/// for IR generation.
class OpenMPIterationSpaceChecker {
  /// Reference to Sema.
  Sema &SemaRef;
  /// A location for diagnostics (when there is no some better location).
  SourceLocation DefaultLoc;
  /// A location for diagnostics (when increment is not compatible).
  SourceLocation ConditionLoc;
  /// A source location for referring to loop init later.
  SourceRange InitSrcRange;
  /// A source location for referring to condition later.
  SourceRange ConditionSrcRange;
  /// A source location for referring to increment later.
  SourceRange IncrementSrcRange;
  /// Loop variable.
  ValueDecl *LCDecl = nullptr;
  /// Reference to loop variable.
  Expr *LCRef = nullptr;
  /// Lower bound (initializer for the var).
  Expr *LB = nullptr;
  /// Upper bound.
  Expr *UB = nullptr;
  /// Loop step (increment).
  Expr *Step = nullptr;
  /// This flag is true when condition is one of:
  ///   Var <  UB
  ///   Var <= UB
  ///   UB  >  Var
  ///   UB  >= Var
  bool TestIsLessOp = false;
  /// This flag is true when condition is strict ( < or > ).
  bool TestIsStrictOp = false;
  /// This flag is true when step is subtracted on each iteration.
  bool SubtractStep = false;

public:
  OpenMPIterationSpaceChecker(Sema &SemaRef, SourceLocation DefaultLoc)
      : SemaRef(SemaRef), DefaultLoc(DefaultLoc), ConditionLoc(DefaultLoc) {}
  /// Check init-expr for canonical loop form and save loop counter
  /// variable - #Var and its initialization value - #LB.
  bool checkAndSetInit(Stmt *S, bool EmitDiags = true);
  /// Check test-expr for canonical form, save upper-bound (#UB), flags
  /// for less/greater and for strict/non-strict comparison.
  bool checkAndSetCond(Expr *S);
  /// Check incr-expr for canonical loop form and return true if it
  /// does not conform, otherwise save loop step (#Step).
  bool checkAndSetInc(Expr *S);
  /// Return the loop counter variable.
  ValueDecl *getLoopDecl() const { return LCDecl; }
  /// Return the reference expression to loop counter variable.
  Expr *getLoopDeclRefExpr() const { return LCRef; }
  /// Source range of the loop init.
  SourceRange getInitSrcRange() const { return InitSrcRange; }
  /// Source range of the loop condition.
  SourceRange getConditionSrcRange() const { return ConditionSrcRange; }
  /// Source range of the loop increment.
  SourceRange getIncrementSrcRange() const { return IncrementSrcRange; }
  /// True if the step should be subtracted.
  bool shouldSubtractStep() const { return SubtractStep; }
  /// Build the expression to calculate the number of iterations.
  Expr *buildNumIterations(
      Scope *S, const bool LimitedType,
      llvm::MapVector<const Expr *, DeclRefExpr *> &Captures) const;
  /// Build the precondition expression for the loops.
  Expr *
  buildPreCond(Scope *S, Expr *Cond,
               llvm::MapVector<const Expr *, DeclRefExpr *> &Captures) const;
  /// Build reference expression to the counter be used for codegen.
  DeclRefExpr *
  buildCounterVar(llvm::MapVector<const Expr *, DeclRefExpr *> &Captures,
                  DSAStackTy &DSA) const;
  /// Build reference expression to the private counter be used for
  /// codegen.
  Expr *buildPrivateCounterVar() const;
  /// Build initialization of the counter be used for codegen.
  Expr *buildCounterInit() const;
  /// Build step of the counter be used for codegen.
  Expr *buildCounterStep() const;
  /// Build loop data with counter value for depend clauses in ordered
  /// directives.
  Expr *
  buildOrderedLoopData(Scope *S, Expr *Counter,
                       llvm::MapVector<const Expr *, DeclRefExpr *> &Captures,
                       SourceLocation Loc, Expr *Inc = nullptr,
                       OverloadedOperatorKind OOK = OO_Amp);
  /// Return true if any expression is dependent.
  bool dependent() const;

private:
  /// Check the right-hand side of an assignment in the increment
  /// expression.
  bool checkAndSetIncRHS(Expr *RHS);
  /// 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);
  /// Helper to set loop increment.
  bool setStep(Expr *NewStep, bool Subtract);
};

bool OpenMPIterationSpaceChecker::dependent() const {
  if (!LCDecl) {
    assert(!LB && !UB && !Step);
    return false;
  }
  return LCDecl->getType()->isDependentType() ||
         (LB && LB->isValueDependent()) || (UB && UB->isValueDependent()) ||
         (Step && Step->isValueDependent());
}

bool OpenMPIterationSpaceChecker::setLCDeclAndLB(ValueDecl *NewLCDecl,
                                                 Expr *NewLCRefExpr,
                                                 Expr *NewLB) {
  // State consistency checking to ensure correct usage.
  assert(LCDecl == nullptr && LB == nullptr && LCRef == nullptr &&
         UB == nullptr && Step == nullptr && !TestIsLessOp && !TestIsStrictOp);
  if (!NewLCDecl || !NewLB)
    return true;
  LCDecl = getCanonicalDecl(NewLCDecl);
  LCRef = NewLCRefExpr;
  if (auto *CE = dyn_cast_or_null<CXXConstructExpr>(NewLB))
    if (const CXXConstructorDecl *Ctor = CE->getConstructor())
      if ((Ctor->isCopyOrMoveConstructor() ||
           Ctor->isConvertingConstructor(/*AllowExplicit=*/false)) &&
          CE->getNumArgs() > 0 && CE->getArg(0) != nullptr)
        NewLB = CE->getArg(0)->IgnoreParenImpCasts();
  LB = NewLB;
  return false;
}

bool OpenMPIterationSpaceChecker::setUB(Expr *NewUB, 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;
  TestIsStrictOp = StrictOp;
  ConditionSrcRange = SR;
  ConditionLoc = SL;
  return false;
}

bool OpenMPIterationSpaceChecker::setStep(Expr *NewStep, bool Subtract) {
  // State consistency checking to ensure correct usage.
  assert(LCDecl != nullptr && LB != nullptr && Step == nullptr);
  if (!NewStep)
    return true;
  if (!NewStep->isValueDependent()) {
    // Check that the step is integer expression.
    SourceLocation StepLoc = NewStep->getBeginLoc();
    ExprResult Val = SemaRef.PerformOpenMPImplicitIntegerConversion(
        StepLoc, getExprAsWritten(NewStep));
    if (Val.isInvalid())
      return true;
    NewStep = Val.get();

    // OpenMP [2.6, Canonical Loop Form, Restrictions]
    //  If test-expr is of form var relational-op b and relational-op is < or
    //  <= then incr-expr must cause var to increase on each iteration of the
    //  loop. If test-expr is of form var relational-op b and relational-op is
    //  > or >= then incr-expr must cause var to decrease on each iteration of
    //  the loop.
    //  If test-expr is of form b relational-op var and relational-op is < or
    //  <= then incr-expr must cause var to decrease on each iteration of the
    //  loop. If test-expr is of form b relational-op var and relational-op is
    //  > or >= then incr-expr must cause var to increase on each iteration of
    //  the loop.
    llvm::APSInt Result;
    bool IsConstant = NewStep->isIntegerConstantExpr(Result, SemaRef.Context);
    bool IsUnsigned = !NewStep->getType()->hasSignedIntegerRepresentation();
    bool IsConstNeg =
        IsConstant && Result.isSigned() && (Subtract != Result.isNegative());
    bool IsConstPos =
        IsConstant && Result.isSigned() && (Subtract == Result.isNegative());
    bool IsConstZero = IsConstant && !Result.getBoolValue();
    if (UB && (IsConstZero ||
               (TestIsLessOp ? (IsConstNeg || (IsUnsigned && Subtract))
                             : (IsConstPos || (IsUnsigned && !Subtract))))) {
      SemaRef.Diag(NewStep->getExprLoc(),
                   diag::err_omp_loop_incr_not_compatible)
          << LCDecl << TestIsLessOp << NewStep->getSourceRange();
      SemaRef.Diag(ConditionLoc,
                   diag::note_omp_loop_cond_requres_compatible_incr)
          << TestIsLessOp << ConditionSrcRange;
      return true;
    }
    if (TestIsLessOp == Subtract) {
      NewStep =
          SemaRef.CreateBuiltinUnaryOp(NewStep->getExprLoc(), UO_Minus, NewStep)
              .get();
      Subtract = !Subtract;
    }
  }

  Step = NewStep;
  SubtractStep = Subtract;
  return false;
}

bool OpenMPIterationSpaceChecker::checkAndSetInit(Stmt *S, bool EmitDiags) {
  // Check init-expr for canonical loop form and save loop counter
  // variable - #Var and its initialization value - #LB.
  // OpenMP [2.6] Canonical loop form. init-expr may be one of the following:
  //   var = lb
  //   integer-type var = lb
  //   random-access-iterator-type var = lb
  //   pointer-type var = lb
  //
  if (!S) {
    if (EmitDiags) {
      SemaRef.Diag(DefaultLoc, diag::err_omp_loop_not_canonical_init);
    }
    return true;
  }
  if (auto *ExprTemp = dyn_cast<ExprWithCleanups>(S))
    if (!ExprTemp->cleanupsHaveSideEffects())
      S = ExprTemp->getSubExpr();

  InitSrcRange = S->getSourceRange();
  if (Expr *E = dyn_cast<Expr>(S))
    S = E->IgnoreParens();
  if (auto *BO = dyn_cast<BinaryOperator>(S)) {
    if (BO->getOpcode() == BO_Assign) {
      Expr *LHS = BO->getLHS()->IgnoreParens();
      if (auto *DRE = dyn_cast<DeclRefExpr>(LHS)) {
        if (auto *CED = dyn_cast<OMPCapturedExprDecl>(DRE->getDecl()))
          if (auto *ME = dyn_cast<MemberExpr>(getExprAsWritten(CED->getInit())))
            return setLCDeclAndLB(ME->getMemberDecl(), ME, BO->getRHS());
        return setLCDeclAndLB(DRE->getDecl(), DRE, BO->getRHS());
      }
      if (auto *ME = dyn_cast<MemberExpr>(LHS)) {
        if (ME->isArrow() &&
            isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts()))
          return setLCDeclAndLB(ME->getMemberDecl(), ME, BO->getRHS());
      }
    }
  } else if (auto *DS = dyn_cast<DeclStmt>(S)) {
    if (DS->isSingleDecl()) {
      if (auto *Var = dyn_cast_or_null<VarDecl>(DS->getSingleDecl())) {
        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->getBeginLoc(),
                         diag::ext_omp_loop_not_canonical_init)
                << S->getSourceRange();
          return setLCDeclAndLB(
              Var,
              buildDeclRefExpr(SemaRef, Var,
                               Var->getType().getNonReferenceType(),
                               DS->getBeginLoc()),
              Var->getInit());
        }
      }
    }
  } else if (auto *CE = dyn_cast<CXXOperatorCallExpr>(S)) {
    if (CE->getOperator() == OO_Equal) {
      Expr *LHS = CE->getArg(0);
      if (auto *DRE = dyn_cast<DeclRefExpr>(LHS)) {
        if (auto *CED = dyn_cast<OMPCapturedExprDecl>(DRE->getDecl()))
          if (auto *ME = dyn_cast<MemberExpr>(getExprAsWritten(CED->getInit())))
            return setLCDeclAndLB(ME->getMemberDecl(), ME, BO->getRHS());
        return setLCDeclAndLB(DRE->getDecl(), DRE, CE->getArg(1));
      }
      if (auto *ME = dyn_cast<MemberExpr>(LHS)) {
        if (ME->isArrow() &&
            isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts()))
          return setLCDeclAndLB(ME->getMemberDecl(), ME, BO->getRHS());
      }
    }
  }

  if (dependent() || SemaRef.CurContext->isDependentContext())
    return false;
  if (EmitDiags) {
    SemaRef.Diag(S->getBeginLoc(), diag::err_omp_loop_not_canonical_init)
        << S->getSourceRange();
  }
  return true;
}

/// Ignore parenthesizes, implicit casts, copy constructor and return the
/// variable (which may be the loop variable) if possible.
static const ValueDecl *getInitLCDecl(const Expr *E) {
  if (!E)
    return nullptr;
  E = getExprAsWritten(E);
  if (const auto *CE = dyn_cast_or_null<CXXConstructExpr>(E))
    if (const CXXConstructorDecl *Ctor = CE->getConstructor())
      if ((Ctor->isCopyOrMoveConstructor() ||
           Ctor->isConvertingConstructor(/*AllowExplicit=*/false)) &&
          CE->getNumArgs() > 0 && CE->getArg(0) != nullptr)
        E = CE->getArg(0)->IgnoreParenImpCasts();
  if (const auto *DRE = dyn_cast_or_null<DeclRefExpr>(E)) {
    if (const auto *VD = dyn_cast<VarDecl>(DRE->getDecl()))
      return getCanonicalDecl(VD);
  }
  if (const auto *ME = dyn_cast_or_null<MemberExpr>(E))
    if (ME->isArrow() && isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts()))
      return getCanonicalDecl(ME->getMemberDecl());
  return nullptr;
}

bool OpenMPIterationSpaceChecker::checkAndSetCond(Expr *S) {
  // Check test-expr for canonical form, save upper-bound UB, flags for
  // less/greater and for strict/non-strict comparison.
  // OpenMP [2.6] Canonical loop form. Test-expr may be one of the following:
  //   var relational-op b
  //   b relational-op var
  //
  if (!S) {
    SemaRef.Diag(DefaultLoc, diag::err_omp_loop_not_canonical_cond) << LCDecl;
    return true;
  }
  S = getExprAsWritten(S);
  SourceLocation CondLoc = S->getBeginLoc();
  if (auto *BO = dyn_cast<BinaryOperator>(S)) {
    if (BO->isRelationalOp()) {
      if (getInitLCDecl(BO->getLHS()) == LCDecl)
        return setUB(BO->getRHS(),
                     (BO->getOpcode() == BO_LT || BO->getOpcode() == BO_LE),
                     (BO->getOpcode() == BO_LT || BO->getOpcode() == BO_GT),
                     BO->getSourceRange(), BO->getOperatorLoc());
      if (getInitLCDecl(BO->getRHS()) == LCDecl)
        return setUB(BO->getLHS(),
                     (BO->getOpcode() == BO_GT || BO->getOpcode() == BO_GE),
                     (BO->getOpcode() == BO_LT || BO->getOpcode() == BO_GT),
                     BO->getSourceRange(), BO->getOperatorLoc());
    }
  } else if (auto *CE = dyn_cast<CXXOperatorCallExpr>(S)) {
    if (CE->getNumArgs() == 2) {
      auto Op = CE->getOperator();
      switch (Op) {
      case OO_Greater:
      case OO_GreaterEqual:
      case OO_Less:
      case OO_LessEqual:
        if (getInitLCDecl(CE->getArg(0)) == LCDecl)
          return setUB(CE->getArg(1), Op == OO_Less || Op == OO_LessEqual,
                       Op == OO_Less || Op == OO_Greater, CE->getSourceRange(),
                       CE->getOperatorLoc());
        if (getInitLCDecl(CE->getArg(1)) == LCDecl)
          return setUB(CE->getArg(0), Op == OO_Greater || Op == OO_GreaterEqual,
                       Op == OO_Less || Op == OO_Greater, CE->getSourceRange(),
                       CE->getOperatorLoc());
        break;
      default:
        break;
      }
    }
  }
  if (dependent() || SemaRef.CurContext->isDependentContext())
    return false;
  SemaRef.Diag(CondLoc, diag::err_omp_loop_not_canonical_cond)
      << S->getSourceRange() << LCDecl;
  return true;
}

bool OpenMPIterationSpaceChecker::checkAndSetIncRHS(Expr *RHS) {
  // RHS of canonical loop form increment can be:
  //   var + incr
  //   incr + var
  //   var - incr
  //
  RHS = RHS->IgnoreParenImpCasts();
  if (auto *BO = dyn_cast<BinaryOperator>(RHS)) {
    if (BO->isAdditiveOp()) {
      bool IsAdd = BO->getOpcode() == BO_Add;
      if (getInitLCDecl(BO->getLHS()) == LCDecl)
        return setStep(BO->getRHS(), !IsAdd);
      if (IsAdd && getInitLCDecl(BO->getRHS()) == LCDecl)
        return setStep(BO->getLHS(), /*Subtract=*/false);
    }
  } else if (auto *CE = dyn_cast<CXXOperatorCallExpr>(RHS)) {
    bool IsAdd = CE->getOperator() == OO_Plus;
    if ((IsAdd || CE->getOperator() == OO_Minus) && CE->getNumArgs() == 2) {
      if (getInitLCDecl(CE->getArg(0)) == LCDecl)
        return setStep(CE->getArg(1), !IsAdd);
      if (IsAdd && getInitLCDecl(CE->getArg(1)) == LCDecl)
        return setStep(CE->getArg(0), /*Subtract=*/false);
    }
  }
  if (dependent() || SemaRef.CurContext->isDependentContext())
    return false;
  SemaRef.Diag(RHS->getBeginLoc(), diag::err_omp_loop_not_canonical_incr)
      << RHS->getSourceRange() << LCDecl;
  return true;
}

bool OpenMPIterationSpaceChecker::checkAndSetInc(Expr *S) {
  // Check incr-expr for canonical loop form and return true if it
  // does not conform.
  // OpenMP [2.6] Canonical loop form. Test-expr may be one of the following:
  //   ++var
  //   var++
  //   --var
  //   var--
  //   var += incr
  //   var -= incr
  //   var = var + incr
  //   var = incr + var
  //   var = var - incr
  //
  if (!S) {
    SemaRef.Diag(DefaultLoc, diag::err_omp_loop_not_canonical_incr) << LCDecl;
    return true;
  }
  if (auto *ExprTemp = dyn_cast<ExprWithCleanups>(S))
    if (!ExprTemp->cleanupsHaveSideEffects())
      S = ExprTemp->getSubExpr();

  IncrementSrcRange = S->getSourceRange();
  S = S->IgnoreParens();
  if (auto *UO = dyn_cast<UnaryOperator>(S)) {
    if (UO->isIncrementDecrementOp() &&
        getInitLCDecl(UO->getSubExpr()) == LCDecl)
      return setStep(SemaRef
                         .ActOnIntegerConstant(UO->getBeginLoc(),
                                               (UO->isDecrementOp() ? -1 : 1))
                         .get(),
                     /*Subtract=*/false);
  } else if (auto *BO = dyn_cast<BinaryOperator>(S)) {
    switch (BO->getOpcode()) {
    case BO_AddAssign:
    case BO_SubAssign:
      if (getInitLCDecl(BO->getLHS()) == LCDecl)
        return setStep(BO->getRHS(), BO->getOpcode() == BO_SubAssign);
      break;
    case BO_Assign:
      if (getInitLCDecl(BO->getLHS()) == LCDecl)
        return checkAndSetIncRHS(BO->getRHS());
      break;
    default:
      break;
    }
  } else if (auto *CE = dyn_cast<CXXOperatorCallExpr>(S)) {
    switch (CE->getOperator()) {
    case OO_PlusPlus:
    case OO_MinusMinus:
      if (getInitLCDecl(CE->getArg(0)) == LCDecl)
        return setStep(SemaRef
                           .ActOnIntegerConstant(
                               CE->getBeginLoc(),
                               ((CE->getOperator() == OO_MinusMinus) ? -1 : 1))
                           .get(),
                       /*Subtract=*/false);
      break;
    case OO_PlusEqual:
    case OO_MinusEqual:
      if (getInitLCDecl(CE->getArg(0)) == LCDecl)
        return setStep(CE->getArg(1), CE->getOperator() == OO_MinusEqual);
      break;
    case OO_Equal:
      if (getInitLCDecl(CE->getArg(0)) == LCDecl)
        return checkAndSetIncRHS(CE->getArg(1));
      break;
    default:
      break;
    }
  }
  if (dependent() || SemaRef.CurContext->isDependentContext())
    return false;
  SemaRef.Diag(S->getBeginLoc(), diag::err_omp_loop_not_canonical_incr)
      << S->getSourceRange() << LCDecl;
  return true;
}

static ExprResult
tryBuildCapture(Sema &SemaRef, Expr *Capture,
                llvm::MapVector<const Expr *, DeclRefExpr *> &Captures) {
  if (SemaRef.CurContext->isDependentContext())
    return ExprResult(Capture);
  if (Capture->isEvaluatable(SemaRef.Context, Expr::SE_AllowSideEffects))
    return SemaRef.PerformImplicitConversion(
        Capture->IgnoreImpCasts(), Capture->getType(), Sema::AA_Converting,
        /*AllowExplicit=*/true);
  auto I = Captures.find(Capture);
  if (I != Captures.end())
    return buildCapture(SemaRef, Capture, I->second);
  DeclRefExpr *Ref = nullptr;
  ExprResult Res = buildCapture(SemaRef, Capture, Ref);
  Captures[Capture] = Ref;
  return Res;
}

/// Build the expression to calculate the number of iterations.
Expr *OpenMPIterationSpaceChecker::buildNumIterations(
    Scope *S, const bool LimitedType,
    llvm::MapVector<const Expr *, DeclRefExpr *> &Captures) const {
  ExprResult Diff;
  QualType VarType = LCDecl->getType().getNonReferenceType();
  if (VarType->isIntegerType() || VarType->isPointerType() ||
      SemaRef.getLangOpts().CPlusPlus) {
    // Upper - Lower
    Expr *UBExpr = TestIsLessOp ? UB : LB;
    Expr *LBExpr = TestIsLessOp ? LB : UB;
    Expr *Upper = tryBuildCapture(SemaRef, UBExpr, Captures).get();
    Expr *Lower = tryBuildCapture(SemaRef, LBExpr, Captures).get();
    if (!Upper || !Lower)
      return nullptr;

    Diff = SemaRef.BuildBinOp(S, DefaultLoc, BO_Sub, Upper, Lower);

    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->getBeginLoc(), diag::err_omp_loop_diff_cxx)
          << Upper->getSourceRange() << Lower->getSourceRange();
      return nullptr;
    }
  }

  if (!Diff.isUsable())
    return nullptr;

  // Upper - Lower [- 1]
  if (TestIsStrictOp)
    Diff = SemaRef.BuildBinOp(
        S, DefaultLoc, BO_Sub, Diff.get(),
        SemaRef.ActOnIntegerConstant(SourceLocation(), 1).get());
  if (!Diff.isUsable())
    return nullptr;

  // Upper - Lower [- 1] + Step
  ExprResult NewStep = tryBuildCapture(SemaRef, Step, Captures);
  if (!NewStep.isUsable())
    return nullptr;
  Diff = SemaRef.BuildBinOp(S, DefaultLoc, BO_Add, Diff.get(), NewStep.get());
  if (!Diff.isUsable())
    return nullptr;

  // Parentheses (for dumping/debugging purposes only).
  Diff = SemaRef.ActOnParenExpr(DefaultLoc, DefaultLoc, Diff.get());
  if (!Diff.isUsable())
    return nullptr;

  // (Upper - Lower [- 1] + Step) / Step
  Diff = SemaRef.BuildBinOp(S, DefaultLoc, BO_Div, Diff.get(), NewStep.get());
  if (!Diff.isUsable())
    return nullptr;

  // OpenMP runtime requires 32-bit or 64-bit loop variables.
  QualType Type = Diff.get()->getType();
  ASTContext &C = SemaRef.Context;
  bool UseVarType = VarType->hasIntegerRepresentation() &&
                    C.getTypeSize(Type) > C.getTypeSize(VarType);
  if (!Type->isIntegerType() || UseVarType) {
    unsigned NewSize =
        UseVarType ? C.getTypeSize(VarType) : C.getTypeSize(Type);
    bool IsSigned = UseVarType ? VarType->hasSignedIntegerRepresentation()
                               : Type->hasSignedIntegerRepresentation();
    Type = C.getIntTypeForBitwidth(NewSize, IsSigned);
    if (!SemaRef.Context.hasSameType(Diff.get()->getType(), Type)) {
      Diff = SemaRef.PerformImplicitConversion(
          Diff.get(), Type, Sema::AA_Converting, /*AllowExplicit=*/true);
      if (!Diff.isUsable())
        return nullptr;
    }
  }
  if (LimitedType) {
    unsigned NewSize = (C.getTypeSize(Type) > 32) ? 64 : 32;
    if (NewSize != C.getTypeSize(Type)) {
      if (NewSize < C.getTypeSize(Type)) {
        assert(NewSize == 64 && "incorrect loop var size");
        SemaRef.Diag(DefaultLoc, diag::warn_omp_loop_64_bit_var)
            << InitSrcRange << ConditionSrcRange;
      }
      QualType NewType = C.getIntTypeForBitwidth(
          NewSize, Type->hasSignedIntegerRepresentation() ||
                       C.getTypeSize(Type) < NewSize);
      if (!SemaRef.Context.hasSameType(Diff.get()->getType(), NewType)) {
        Diff = SemaRef.PerformImplicitConversion(Diff.get(), NewType,
                                                 Sema::AA_Converting, true);
        if (!Diff.isUsable())
          return nullptr;
      }
    }
  }

  return Diff.get();
}

Expr *OpenMPIterationSpaceChecker::buildPreCond(
    Scope *S, Expr *Cond,
    llvm::MapVector<const Expr *, DeclRefExpr *> &Captures) const {
  // Try to build LB <op> UB, where <op> is <, >, <=, or >=.
  bool Suppress = SemaRef.getDiagnostics().getSuppressAllDiagnostics();
  SemaRef.getDiagnostics().setSuppressAllDiagnostics(/*Val=*/true);

  ExprResult NewLB = tryBuildCapture(SemaRef, LB, Captures);
  ExprResult NewUB = tryBuildCapture(SemaRef, UB, Captures);
  if (!NewLB.isUsable() || !NewUB.isUsable())
    return nullptr;

  ExprResult CondExpr =
      SemaRef.BuildBinOp(S, DefaultLoc,
                         TestIsLessOp ? (TestIsStrictOp ? BO_LT : BO_LE)
                                      : (TestIsStrictOp ? BO_GT : BO_GE),
                         NewLB.get(), NewUB.get());
  if (CondExpr.isUsable()) {
    if (!SemaRef.Context.hasSameUnqualifiedType(CondExpr.get()->getType(),
                                                SemaRef.Context.BoolTy))
      CondExpr = SemaRef.PerformImplicitConversion(
          CondExpr.get(), SemaRef.Context.BoolTy, /*Action=*/Sema::AA_Casting,
          /*AllowExplicit=*/true);
  }
  SemaRef.getDiagnostics().setSuppressAllDiagnostics(Suppress);
  // Otherwise use original loop conditon and evaluate it in runtime.
  return CondExpr.isUsable() ? CondExpr.get() : Cond;
}

/// Build reference expression to the counter be used for codegen.
DeclRefExpr *OpenMPIterationSpaceChecker::buildCounterVar(
    llvm::MapVector<const Expr *, DeclRefExpr *> &Captures,
    DSAStackTy &DSA) const {
  auto *VD = dyn_cast<VarDecl>(LCDecl);
  if (!VD) {
    VD = SemaRef.isOpenMPCapturedDecl(LCDecl);
    DeclRefExpr *Ref = buildDeclRefExpr(
        SemaRef, VD, VD->getType().getNonReferenceType(), DefaultLoc);
    const DSAStackTy::DSAVarData Data =
        DSA.getTopDSA(LCDecl, /*FromParent=*/false);
    // If the loop control decl is explicitly marked as private, do not mark it
    // as captured again.
    if (!isOpenMPPrivate(Data.CKind) || !Data.RefExpr)
      Captures.insert(std::make_pair(LCRef, Ref));
    return Ref;
  }
  return buildDeclRefExpr(SemaRef, VD, VD->getType().getNonReferenceType(),
                          DefaultLoc);
}

Expr *OpenMPIterationSpaceChecker::buildPrivateCounterVar() const {
  if (LCDecl && !LCDecl->isInvalidDecl()) {
    QualType Type = LCDecl->getType().getNonReferenceType();
    VarDecl *PrivateVar = buildVarDecl(
        SemaRef, DefaultLoc, Type, LCDecl->getName(),
        LCDecl->hasAttrs() ? &LCDecl->getAttrs() : nullptr,
        isa<VarDecl>(LCDecl)
            ? buildDeclRefExpr(SemaRef, cast<VarDecl>(LCDecl), Type, DefaultLoc)
            : nullptr);
    if (PrivateVar->isInvalidDecl())
      return nullptr;
    return buildDeclRefExpr(SemaRef, PrivateVar, Type, DefaultLoc);
  }
  return nullptr;
}

/// Build initialization of the counter to be used for codegen.
Expr *OpenMPIterationSpaceChecker::buildCounterInit() const { return LB; }

/// Build step of the counter be used for codegen.
Expr *OpenMPIterationSpaceChecker::buildCounterStep() const { return Step; }

Expr *OpenMPIterationSpaceChecker::buildOrderedLoopData(
    Scope *S, Expr *Counter,
    llvm::MapVector<const Expr *, DeclRefExpr *> &Captures, SourceLocation Loc,
    Expr *Inc, OverloadedOperatorKind OOK) {
  Expr *Cnt = SemaRef.DefaultLvalueConversion(Counter).get();
  if (!Cnt)
    return nullptr;
  if (Inc) {
    assert((OOK == OO_Plus || OOK == OO_Minus) &&
           "Expected only + or - operations for depend clauses.");
    BinaryOperatorKind BOK = (OOK == OO_Plus) ? BO_Add : BO_Sub;
    Cnt = SemaRef.BuildBinOp(S, Loc, BOK, Cnt, Inc).get();
    if (!Cnt)
      return nullptr;
  }
  ExprResult Diff;
  QualType VarType = LCDecl->getType().getNonReferenceType();
  if (VarType->isIntegerType() || VarType->isPointerType() ||
      SemaRef.getLangOpts().CPlusPlus) {
    // Upper - Lower
    Expr *Upper =
        TestIsLessOp ? Cnt : tryBuildCapture(SemaRef, UB, Captures).get();
    Expr *Lower =
        TestIsLessOp ? tryBuildCapture(SemaRef, LB, Captures).get() : Cnt;
    if (!Upper || !Lower)
      return nullptr;

    Diff = SemaRef.BuildBinOp(S, DefaultLoc, BO_Sub, Upper, Lower);

    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->getBeginLoc(), diag::err_omp_loop_diff_cxx)
          << Upper->getSourceRange() << Lower->getSourceRange();
      return nullptr;
    }
  }

  if (!Diff.isUsable())
    return nullptr;

  // Parentheses (for dumping/debugging purposes only).
  Diff = SemaRef.ActOnParenExpr(DefaultLoc, DefaultLoc, Diff.get());
  if (!Diff.isUsable())
    return nullptr;

  ExprResult NewStep = tryBuildCapture(SemaRef, Step, Captures);
  if (!NewStep.isUsable())
    return nullptr;
  // (Upper - Lower) / Step
  Diff = SemaRef.BuildBinOp(S, DefaultLoc, BO_Div, Diff.get(), NewStep.get());
  if (!Diff.isUsable())
    return nullptr;

  return Diff.get();
}

/// Iteration space of a single for loop.
struct LoopIterationSpace final {
  /// Condition of the loop.
  Expr *PreCond = nullptr;
  /// This expression calculates the number of iterations in the loop.
  /// It is always possible to calculate it before starting the loop.
  Expr *NumIterations = nullptr;
  /// The loop counter variable.
  Expr *CounterVar = nullptr;
  /// Private loop counter variable.
  Expr *PrivateCounterVar = nullptr;
  /// This is initializer for the initial value of #CounterVar.
  Expr *CounterInit = nullptr;
  /// This is step for the #CounterVar used to generate its update:
  /// #CounterVar = #CounterInit + #CounterStep * CurrentIteration.
  Expr *CounterStep = nullptr;
  /// Should step be subtracted?
  bool Subtract = false;
  /// Source range of the loop init.
  SourceRange InitSrcRange;
  /// Source range of the loop condition.
  SourceRange CondSrcRange;
  /// Source range of the loop increment.
  SourceRange IncSrcRange;
};

} // namespace

void Sema::ActOnOpenMPLoopInitialization(SourceLocation ForLoc, Stmt *Init) {
  assert(getLangOpts().OpenMP && "OpenMP is not active.");
  assert(Init && "Expected loop in canonical form.");
  unsigned AssociatedLoops = DSAStack->getAssociatedLoops();
  if (AssociatedLoops > 0 &&
      isOpenMPLoopDirective(DSAStack->getCurrentDirective())) {
    OpenMPIterationSpaceChecker ISC(*this, ForLoc);
    if (!ISC.checkAndSetInit(Init, /*EmitDiags=*/false)) {
      if (ValueDecl *D = ISC.getLoopDecl()) {
        auto *VD = dyn_cast<VarDecl>(D);
        if (!VD) {
          if (VarDecl *Private = isOpenMPCapturedDecl(D)) {
            VD = Private;
          } else {
            DeclRefExpr *Ref = buildCapture(*this, D, ISC.getLoopDeclRefExpr(),
                                            /*WithInit=*/false);
            VD = cast<VarDecl>(Ref->getDecl());
          }
        }
        DSAStack->addLoopControlVariable(D, VD);
      }
    }
    DSAStack->setAssociatedLoops(AssociatedLoops - 1);
  }
}

/// Called on a for stmt to check and extract its iteration space
/// for further processing (such as collapsing).
static bool checkOpenMPIterationSpace(
    OpenMPDirectiveKind DKind, Stmt *S, Sema &SemaRef, DSAStackTy &DSA,
    unsigned CurrentNestedLoopCount, unsigned NestedLoopCount,
    unsigned TotalNestedLoopCount, Expr *CollapseLoopCountExpr,
    Expr *OrderedLoopCountExpr,
    Sema::VarsWithInheritedDSAType &VarsWithImplicitDSA,
    LoopIterationSpace &ResultIterSpace,
    llvm::MapVector<const Expr *, DeclRefExpr *> &Captures) {
  // OpenMP [2.6, Canonical Loop Form]
  //   for (init-expr; test-expr; incr-expr) structured-block
  auto *For = dyn_cast_or_null<ForStmt>(S);
  if (!For) {
    SemaRef.Diag(S->getBeginLoc(), diag::err_omp_not_for)
        << (CollapseLoopCountExpr != nullptr || OrderedLoopCountExpr != nullptr)
        << getOpenMPDirectiveName(DKind) << TotalNestedLoopCount
        << (CurrentNestedLoopCount > 0) << CurrentNestedLoopCount;
    if (TotalNestedLoopCount > 1) {
      if (CollapseLoopCountExpr && OrderedLoopCountExpr)
        SemaRef.Diag(DSA.getConstructLoc(),
                     diag::note_omp_collapse_ordered_expr)
            << 2 << CollapseLoopCountExpr->getSourceRange()
            << OrderedLoopCountExpr->getSourceRange();
      else if (CollapseLoopCountExpr)
        SemaRef.Diag(CollapseLoopCountExpr->getExprLoc(),
                     diag::note_omp_collapse_ordered_expr)
            << 0 << CollapseLoopCountExpr->getSourceRange();
      else
        SemaRef.Diag(OrderedLoopCountExpr->getExprLoc(),
                     diag::note_omp_collapse_ordered_expr)
            << 1 << OrderedLoopCountExpr->getSourceRange();
    }
    return true;
  }
  assert(For->getBody());

  OpenMPIterationSpaceChecker ISC(SemaRef, For->getForLoc());

  // Check init.
  Stmt *Init = For->getInit();
  if (ISC.checkAndSetInit(Init))
    return true;

  bool HasErrors = false;

  // Check loop variable's type.
  if (ValueDecl *LCDecl = ISC.getLoopDecl()) {
    Expr *LoopDeclRefExpr = ISC.getLoopDeclRefExpr();

    // OpenMP [2.6, Canonical Loop Form]
    // Var is one of the following:
    //   A variable of signed or unsigned integer type.
    //   For C++, a variable of a random access iterator type.
    //   For C, a variable of a pointer type.
    QualType VarType = LCDecl->getType().getNonReferenceType();
    if (!VarType->isDependentType() && !VarType->isIntegerType() &&
        !VarType->isPointerType() &&
        !(SemaRef.getLangOpts().CPlusPlus && VarType->isOverloadableType())) {
      SemaRef.Diag(Init->getBeginLoc(), diag::err_omp_loop_variable_type)
          << SemaRef.getLangOpts().CPlusPlus;
      HasErrors = true;
    }

    // OpenMP, 2.14.1.1 Data-sharing Attribute Rules for Variables Referenced in
    // a Construct
    // The loop iteration variable(s) in the associated for-loop(s) of a for or
    // parallel for construct is (are) private.
    // The loop iteration variable in the associated for-loop of a simd
    // construct with just one associated for-loop is linear with a
    // constant-linear-step that is the increment of the associated for-loop.
    // Exclude loop var from the list of variables with implicitly defined data
    // sharing attributes.
    VarsWithImplicitDSA.erase(LCDecl);

    // OpenMP [2.14.1.1, Data-sharing Attribute Rules for Variables Referenced
    // in a Construct, C/C++].
    // The loop iteration variable in the associated for-loop of a simd
    // construct with just one associated for-loop may be listed in a linear
    // clause with a constant-linear-step that is the increment of the
    // associated for-loop.
    // The loop iteration variable(s) in the associated for-loop(s) of a for or
    // parallel for construct may be listed in a private or lastprivate clause.
    DSAStackTy::DSAVarData DVar = DSA.getTopDSA(LCDecl, false);
    // If LoopVarRefExpr is nullptr it means the corresponding loop variable is
    // declared in the loop and it is predetermined as a private.
    OpenMPClauseKind PredeterminedCKind =
        isOpenMPSimdDirective(DKind)
            ? ((NestedLoopCount == 1) ? OMPC_linear : OMPC_lastprivate)
            : OMPC_private;
    if (((isOpenMPSimdDirective(DKind) && DVar.CKind != OMPC_unknown &&
          DVar.CKind != PredeterminedCKind) ||
         ((isOpenMPWorksharingDirective(DKind) || DKind == OMPD_taskloop ||
           isOpenMPDistributeDirective(DKind)) &&
          !isOpenMPSimdDirective(DKind) && DVar.CKind != OMPC_unknown &&
          DVar.CKind != OMPC_private && DVar.CKind != OMPC_lastprivate)) &&
        (DVar.CKind != OMPC_private || DVar.RefExpr != nullptr)) {
      SemaRef.Diag(Init->getBeginLoc(), diag::err_omp_loop_var_dsa)
          << getOpenMPClauseName(DVar.CKind) << getOpenMPDirectiveName(DKind)
          << getOpenMPClauseName(PredeterminedCKind);
      if (DVar.RefExpr == nullptr)
        DVar.CKind = PredeterminedCKind;
      reportOriginalDsa(SemaRef, &DSA, LCDecl, DVar, /*IsLoopIterVar=*/true);
      HasErrors = true;
    } else if (LoopDeclRefExpr != nullptr) {
      // Make the loop iteration variable private (for worksharing constructs),
      // linear (for simd directives with the only one associated loop) or
      // lastprivate (for simd directives with several collapsed or ordered
      // loops).
      if (DVar.CKind == OMPC_unknown)
        DVar = DSA.hasDSA(LCDecl, isOpenMPPrivate,
                          [](OpenMPDirectiveKind) -> bool { return true; },
                          /*FromParent=*/false);
      DSA.addDSA(LCDecl, LoopDeclRefExpr, PredeterminedCKind);
    }

    assert(isOpenMPLoopDirective(DKind) && "DSA for non-loop vars");

    // Check test-expr.
    HasErrors |= ISC.checkAndSetCond(For->getCond());

    // Check incr-expr.
    HasErrors |= ISC.checkAndSetInc(For->getInc());
  }

  if (ISC.dependent() || SemaRef.CurContext->isDependentContext() || HasErrors)
    return HasErrors;

  // Build the loop's iteration space representation.
  ResultIterSpace.PreCond =
      ISC.buildPreCond(DSA.getCurScope(), For->getCond(), Captures);
  ResultIterSpace.NumIterations = ISC.buildNumIterations(
      DSA.getCurScope(),
      (isOpenMPWorksharingDirective(DKind) ||
       isOpenMPTaskLoopDirective(DKind) || isOpenMPDistributeDirective(DKind)),
      Captures);
  ResultIterSpace.CounterVar = ISC.buildCounterVar(Captures, DSA);
  ResultIterSpace.PrivateCounterVar = ISC.buildPrivateCounterVar();
  ResultIterSpace.CounterInit = ISC.buildCounterInit();
  ResultIterSpace.CounterStep = ISC.buildCounterStep();
  ResultIterSpace.InitSrcRange = ISC.getInitSrcRange();
  ResultIterSpace.CondSrcRange = ISC.getConditionSrcRange();
  ResultIterSpace.IncSrcRange = ISC.getIncrementSrcRange();
  ResultIterSpace.Subtract = ISC.shouldSubtractStep();

  HasErrors |= (ResultIterSpace.PreCond == nullptr ||
                ResultIterSpace.NumIterations == nullptr ||
                ResultIterSpace.CounterVar == nullptr ||
                ResultIterSpace.PrivateCounterVar == nullptr ||
                ResultIterSpace.CounterInit == nullptr ||
                ResultIterSpace.CounterStep == nullptr);
  if (!HasErrors && DSA.isOrderedRegion()) {
    if (DSA.getOrderedRegionParam().second->getNumForLoops()) {
      if (CurrentNestedLoopCount <
          DSA.getOrderedRegionParam().second->getLoopNumIterations().size()) {
        DSA.getOrderedRegionParam().second->setLoopNumIterations(
            CurrentNestedLoopCount, ResultIterSpace.NumIterations);
        DSA.getOrderedRegionParam().second->setLoopCounter(
            CurrentNestedLoopCount, ResultIterSpace.CounterVar);
      }
    }
    for (auto &Pair : DSA.getDoacrossDependClauses()) {
      if (CurrentNestedLoopCount >= Pair.first->getNumLoops()) {
        // Erroneous case - clause has some problems.
        continue;
      }
      if (Pair.first->getDependencyKind() == OMPC_DEPEND_sink &&
          Pair.second.size() <= CurrentNestedLoopCount) {
        // Erroneous case - clause has some problems.
        Pair.first->setLoopData(CurrentNestedLoopCount, nullptr);
        continue;
      }
      Expr *CntValue;
      if (Pair.first->getDependencyKind() == OMPC_DEPEND_source)
        CntValue = ISC.buildOrderedLoopData(
            DSA.getCurScope(), ResultIterSpace.CounterVar, Captures,
            Pair.first->getDependencyLoc());
      else
        CntValue = ISC.buildOrderedLoopData(
            DSA.getCurScope(), ResultIterSpace.CounterVar, Captures,
            Pair.first->getDependencyLoc(),
            Pair.second[CurrentNestedLoopCount].first,
            Pair.second[CurrentNestedLoopCount].second);
      Pair.first->setLoopData(CurrentNestedLoopCount, CntValue);
    }
  }

  return HasErrors;
}

/// Build 'VarRef = Start.
static ExprResult
buildCounterInit(Sema &SemaRef, Scope *S, SourceLocation Loc, ExprResult VarRef,
                 ExprResult Start,
                 llvm::MapVector<const Expr *, DeclRefExpr *> &Captures) {
  // Build 'VarRef = Start.
  ExprResult NewStart = tryBuildCapture(SemaRef, Start.get(), Captures);
  if (!NewStart.isUsable())
    return ExprError();
  if (!SemaRef.Context.hasSameType(NewStart.get()->getType(),
                                   VarRef.get()->getType())) {
    NewStart = SemaRef.PerformImplicitConversion(
        NewStart.get(), VarRef.get()->getType(), Sema::AA_Converting,
        /*AllowExplicit=*/true);
    if (!NewStart.isUsable())
      return ExprError();
  }

  ExprResult Init =
      SemaRef.BuildBinOp(S, Loc, BO_Assign, VarRef.get(), NewStart.get());
  return Init;
}

/// Build 'VarRef = Start + Iter * Step'.
static ExprResult buildCounterUpdate(
    Sema &SemaRef, Scope *S, SourceLocation Loc, ExprResult VarRef,
    ExprResult Start, ExprResult Iter, ExprResult Step, bool Subtract,
    llvm::MapVector<const Expr *, DeclRefExpr *> *Captures = nullptr) {
  // Add parentheses (for debugging purposes only).
  Iter = SemaRef.ActOnParenExpr(Loc, Loc, Iter.get());
  if (!VarRef.isUsable() || !Start.isUsable() || !Iter.isUsable() ||
      !Step.isUsable())
    return ExprError();

  ExprResult NewStep = Step;
  if (Captures)
    NewStep = tryBuildCapture(SemaRef, Step.get(), *Captures);
  if (NewStep.isInvalid())
    return ExprError();
  ExprResult Update =
      SemaRef.BuildBinOp(S, Loc, BO_Mul, Iter.get(), NewStep.get());
  if (!Update.isUsable())
    return ExprError();

  // Try to build 'VarRef = Start, VarRef (+|-)= Iter * Step' or
  // 'VarRef = Start (+|-) Iter * Step'.
  ExprResult NewStart = Start;
  if (Captures)
    NewStart = tryBuildCapture(SemaRef, Start.get(), *Captures);
  if (NewStart.isInvalid())
    return ExprError();

  // First attempt: try to build 'VarRef = Start, VarRef += Iter * Step'.
  ExprResult SavedUpdate = Update;
  ExprResult UpdateVal;
  if (VarRef.get()->getType()->isOverloadableType() ||
      NewStart.get()->getType()->isOverloadableType() ||
      Update.get()->getType()->isOverloadableType()) {
    bool Suppress = SemaRef.getDiagnostics().getSuppressAllDiagnostics();
    SemaRef.getDiagnostics().setSuppressAllDiagnostics(/*Val=*/true);
    Update =
        SemaRef.BuildBinOp(S, Loc, BO_Assign, VarRef.get(), NewStart.get());
    if (Update.isUsable()) {
      UpdateVal =
          SemaRef.BuildBinOp(S, Loc, Subtract ? BO_SubAssign : BO_AddAssign,
                             VarRef.get(), SavedUpdate.get());
      if (UpdateVal.isUsable()) {
        Update = SemaRef.CreateBuiltinBinOp(Loc, BO_Comma, Update.get(),
                                            UpdateVal.get());
      }
    }
    SemaRef.getDiagnostics().setSuppressAllDiagnostics(Suppress);
  }

  // Second attempt: try to build 'VarRef = Start (+|-) Iter * Step'.
  if (!Update.isUsable() || !UpdateVal.isUsable()) {
    Update = SemaRef.BuildBinOp(S, Loc, Subtract ? BO_Sub : BO_Add,
                                NewStart.get(), SavedUpdate.get());
    if (!Update.isUsable())
      return ExprError();

    if (!SemaRef.Context.hasSameType(Update.get()->getType(),
                                     VarRef.get()->getType())) {
      Update = SemaRef.PerformImplicitConversion(
          Update.get(), VarRef.get()->getType(), Sema::AA_Converting, true);
      if (!Update.isUsable())
        return ExprError();
    }

    Update = SemaRef.BuildBinOp(S, Loc, BO_Assign, VarRef.get(), Update.get());
  }
  return Update;
}

/// Convert integer expression \a E to make it have at least \a Bits
/// bits.
static ExprResult widenIterationCount(unsigned Bits, Expr *E, Sema &SemaRef) {
  if (E == nullptr)
    return ExprError();
  ASTContext &C = SemaRef.Context;
  QualType OldType = E->getType();
  unsigned HasBits = C.getTypeSize(OldType);
  if (HasBits >= Bits)
    return ExprResult(E);
  // OK to convert to signed, because new type has more bits than old.
  QualType NewType = C.getIntTypeForBitwidth(Bits, /* Signed */ true);
  return SemaRef.PerformImplicitConversion(E, NewType, Sema::AA_Converting,
                                           true);
}

/// Check if the given expression \a E is a constant integer that fits
/// into \a Bits bits.
static bool fitsInto(unsigned Bits, bool Signed, const Expr *E, Sema &SemaRef) {
  if (E == nullptr)
    return false;
  llvm::APSInt Result;
  if (E->isIntegerConstantExpr(Result, SemaRef.Context))
    return Signed ? Result.isSignedIntN(Bits) : Result.isIntN(Bits);
  return false;
}

/// Build preinits statement for the given declarations.
static Stmt *buildPreInits(ASTContext &Context,
                           MutableArrayRef<Decl *> PreInits) {
  if (!PreInits.empty()) {
    return new (Context) DeclStmt(
        DeclGroupRef::Create(Context, PreInits.begin(), PreInits.size()),
        SourceLocation(), SourceLocation());
  }
  return nullptr;
}

/// Build preinits statement for the given declarations.
static Stmt *
buildPreInits(ASTContext &Context,
              const llvm::MapVector<const Expr *, DeclRefExpr *> &Captures) {
  if (!Captures.empty()) {
    SmallVector<Decl *, 16> PreInits;
    for (const auto &Pair : Captures)
      PreInits.push_back(Pair.second->getDecl());
    return buildPreInits(Context, PreInits);
  }
  return nullptr;
}

/// Build postupdate expression for the given list of postupdates expressions.
static Expr *buildPostUpdate(Sema &S, ArrayRef<Expr *> PostUpdates) {
  Expr *PostUpdate = nullptr;
  if (!PostUpdates.empty()) {
    for (Expr *E : PostUpdates) {
      Expr *ConvE = S.BuildCStyleCastExpr(
                         E->getExprLoc(),
                         S.Context.getTrivialTypeSourceInfo(S.Context.VoidTy),
                         E->getExprLoc(), E)
                        .get();
      PostUpdate = PostUpdate
                       ? S.CreateBuiltinBinOp(ConvE->getExprLoc(), BO_Comma,
                                              PostUpdate, ConvE)
                             .get()
                       : ConvE;
    }
  }
  return PostUpdate;
}

/// Called on a for stmt to check itself and nested loops (if any).
/// \return Returns 0 if one of the collapsed stmts is not canonical for loop,
/// number of collapsed loops otherwise.
static unsigned
checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
                Expr *OrderedLoopCountExpr, Stmt *AStmt, Sema &SemaRef,
                DSAStackTy &DSA,
                Sema::VarsWithInheritedDSAType &VarsWithImplicitDSA,
                OMPLoopDirective::HelperExprs &Built) {
  unsigned NestedLoopCount = 1;
  if (CollapseLoopCountExpr) {
    // Found 'collapse' clause - calculate collapse number.
    llvm::APSInt Result;
    if (CollapseLoopCountExpr->EvaluateAsInt(Result, SemaRef.getASTContext()))
      NestedLoopCount = Result.getLimitedValue();
  }
  unsigned OrderedLoopCount = 1;
  if (OrderedLoopCountExpr) {
    // Found 'ordered' clause - calculate collapse number.
    llvm::APSInt Result;
    if (OrderedLoopCountExpr->EvaluateAsInt(Result, SemaRef.getASTContext())) {
      if (Result.getLimitedValue() < NestedLoopCount) {
        SemaRef.Diag(OrderedLoopCountExpr->getExprLoc(),
                     diag::err_omp_wrong_ordered_loop_count)
            << OrderedLoopCountExpr->getSourceRange();
        SemaRef.Diag(CollapseLoopCountExpr->getExprLoc(),
                     diag::note_collapse_loop_count)
            << CollapseLoopCountExpr->getSourceRange();
      }
      OrderedLoopCount = Result.getLimitedValue();
    }
  }
  // This is helper routine for loop directives (e.g., 'for', 'simd',
  // 'for simd', etc.).
  llvm::MapVector<const Expr *, DeclRefExpr *> Captures;
  SmallVector<LoopIterationSpace, 4> IterSpaces;
  IterSpaces.resize(std::max(OrderedLoopCount, NestedLoopCount));
  Stmt *CurStmt = AStmt->IgnoreContainers(/* IgnoreCaptured */ true);
  for (unsigned Cnt = 0; Cnt < NestedLoopCount; ++Cnt) {
    if (checkOpenMPIterationSpace(
            DKind, CurStmt, SemaRef, DSA, Cnt, NestedLoopCount,
            std::max(OrderedLoopCount, NestedLoopCount), CollapseLoopCountExpr,
            OrderedLoopCountExpr, VarsWithImplicitDSA, IterSpaces[Cnt],
            Captures))
      return 0;
    // Move on to the next nested for loop, or to the loop body.
    // OpenMP [2.8.1, simd construct, Restrictions]
    // All loops associated with the construct must be perfectly nested; that
    // is, there must be no intervening code nor any OpenMP directive between
    // any two loops.
    CurStmt = cast<ForStmt>(CurStmt)->getBody()->IgnoreContainers();
  }
  for (unsigned Cnt = NestedLoopCount; Cnt < OrderedLoopCount; ++Cnt) {
    if (checkOpenMPIterationSpace(
            DKind, CurStmt, SemaRef, DSA, Cnt, NestedLoopCount,
            std::max(OrderedLoopCount, NestedLoopCount), CollapseLoopCountExpr,
            OrderedLoopCountExpr, VarsWithImplicitDSA, IterSpaces[Cnt],
            Captures))
      return 0;
    if (Cnt > 0 && IterSpaces[Cnt].CounterVar) {
      // Handle initialization of captured loop iterator variables.
      auto *DRE = cast<DeclRefExpr>(IterSpaces[Cnt].CounterVar);
      if (isa<OMPCapturedExprDecl>(DRE->getDecl())) {
        Captures[DRE] = DRE;
      }
    }
    // Move on to the next nested for loop, or to the loop body.
    // OpenMP [2.8.1, simd construct, Restrictions]
    // All loops associated with the construct must be perfectly nested; that
    // is, there must be no intervening code nor any OpenMP directive between
    // any two loops.
    CurStmt = cast<ForStmt>(CurStmt)->getBody()->IgnoreContainers();
  }

  Built.clear(/* size */ NestedLoopCount);

  if (SemaRef.CurContext->isDependentContext())
    return NestedLoopCount;

  // An example of what is generated for the following code:
  //
  //   #pragma omp simd collapse(2) ordered(2)
  //   for (i = 0; i < NI; ++i)
  //     for (k = 0; k < NK; ++k)
  //       for (j = J0; j < NJ; j+=2) {
  //         <loop body>
  //       }
  //
  // We generate the code below.
  // Note: the loop body may be outlined in CodeGen.
  // Note: some counters may be C++ classes, operator- is used to find number of
  // iterations and operator+= to calculate counter value.
  // Note: decltype(NumIterations) must be integer type (in 'omp for', only i32
  // or i64 is currently supported).
  //
  //   #define NumIterations (NI * ((NJ - J0 - 1 + 2) / 2))
  //   for (int[32|64]_t IV = 0; IV < NumIterations; ++IV ) {
  //     .local.i = IV / ((NJ - J0 - 1 + 2) / 2);
  //     .local.j = J0 + (IV % ((NJ - J0 - 1 + 2) / 2)) * 2;
  //     // similar updates for vars in clauses (e.g. 'linear')
  //     <loop body (using local i and j)>
  //   }
  //   i = NI; // assign final values of counters
  //   j = NJ;
  //

  // Last iteration number is (I1 * I2 * ... In) - 1, where I1, I2 ... In are
  // the iteration counts of the collapsed for loops.
  // Precondition tests if there is at least one iteration (all conditions are
  // true).
  auto PreCond = ExprResult(IterSpaces[0].PreCond);
  Expr *N0 = IterSpaces[0].NumIterations;
  ExprResult LastIteration32 =
      widenIterationCount(/*Bits=*/32,
                          SemaRef
                              .PerformImplicitConversion(
                                  N0->IgnoreImpCasts(), N0->getType(),
                                  Sema::AA_Converting, /*AllowExplicit=*/true)
                              .get(),
                          SemaRef);
  ExprResult LastIteration64 = widenIterationCount(
      /*Bits=*/64,
      SemaRef
          .PerformImplicitConversion(N0->IgnoreImpCasts(), N0->getType(),
                                     Sema::AA_Converting,
                                     /*AllowExplicit=*/true)
          .get(),
      SemaRef);

  if (!LastIteration32.isUsable() || !LastIteration64.isUsable())
    return NestedLoopCount;

  ASTContext &C = SemaRef.Context;
  bool AllCountsNeedLessThan32Bits = C.getTypeSize(N0->getType()) < 32;

  Scope *CurScope = DSA.getCurScope();
  for (unsigned Cnt = 1; Cnt < NestedLoopCount; ++Cnt) {
    if (PreCond.isUsable()) {
      PreCond =
          SemaRef.BuildBinOp(CurScope, PreCond.get()->getExprLoc(), BO_LAnd,
                             PreCond.get(), IterSpaces[Cnt].PreCond);
    }
    Expr *N = IterSpaces[Cnt].NumIterations;
    SourceLocation Loc = N->getExprLoc();
    AllCountsNeedLessThan32Bits &= C.getTypeSize(N->getType()) < 32;
    if (LastIteration32.isUsable())
      LastIteration32 = SemaRef.BuildBinOp(
          CurScope, Loc, BO_Mul, LastIteration32.get(),
          SemaRef
              .PerformImplicitConversion(N->IgnoreImpCasts(), N->getType(),
                                         Sema::AA_Converting,
                                         /*AllowExplicit=*/true)
              .get());
    if (LastIteration64.isUsable())
      LastIteration64 = SemaRef.BuildBinOp(
          CurScope, Loc, BO_Mul, LastIteration64.get(),
          SemaRef
              .PerformImplicitConversion(N->IgnoreImpCasts(), N->getType(),
                                         Sema::AA_Converting,
                                         /*AllowExplicit=*/true)
              .get());
  }

  // 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)))
    LastIteration = LastIteration32;
  QualType VType = LastIteration.get()->getType();
  QualType RealVType = VType;
  QualType StrideVType = VType;
  if (isOpenMPTaskLoopDirective(DKind)) {
    VType =
        SemaRef.Context.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/0);
    StrideVType =
        SemaRef.Context.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/1);
  }

  if (!LastIteration.isUsable())
    return 0;

  // Save the number of iterations.
  ExprResult NumIterations = LastIteration;
  {
    LastIteration = SemaRef.BuildBinOp(
        CurScope, LastIteration.get()->getExprLoc(), BO_Sub,
        LastIteration.get(),
        SemaRef.ActOnIntegerConstant(SourceLocation(), 1).get());
    if (!LastIteration.isUsable())
      return 0;
  }

  // Calculate the last iteration number beforehand instead of doing this on
  // each iteration. Do not do this if the number of iterations may be kfold-ed.
  llvm::APSInt Result;
  bool IsConstant =
      LastIteration.get()->isIntegerConstantExpr(Result, SemaRef.Context);
  ExprResult CalcLastIteration;
  if (!IsConstant) {
    ExprResult SaveRef =
        tryBuildCapture(SemaRef, LastIteration.get(), Captures);
    LastIteration = SaveRef;

    // Prepare SaveRef + 1.
    NumIterations = SemaRef.BuildBinOp(
        CurScope, SaveRef.get()->getExprLoc(), BO_Add, SaveRef.get(),
        SemaRef.ActOnIntegerConstant(SourceLocation(), 1).get());
    if (!NumIterations.isUsable())
      return 0;
  }

  SourceLocation InitLoc = IterSpaces[0].InitSrcRange.getBegin();

  // Build variables passed into runtime, necessary for worksharing directives.
  ExprResult LB, UB, IL, ST, EUB, CombLB, CombUB, PrevLB, PrevUB, CombEUB;
  if (isOpenMPWorksharingDirective(DKind) || isOpenMPTaskLoopDirective(DKind) ||
      isOpenMPDistributeDirective(DKind)) {
    // Lower bound variable, initialized with zero.
    VarDecl *LBDecl = buildVarDecl(SemaRef, InitLoc, VType, ".omp.lb");
    LB = buildDeclRefExpr(SemaRef, LBDecl, VType, InitLoc);
    SemaRef.AddInitializerToDecl(LBDecl,
                                 SemaRef.ActOnIntegerConstant(InitLoc, 0).get(),
                                 /*DirectInit*/ false);

    // Upper bound variable, initialized with last iteration number.
    VarDecl *UBDecl = buildVarDecl(SemaRef, InitLoc, VType, ".omp.ub");
    UB = buildDeclRefExpr(SemaRef, UBDecl, VType, InitLoc);
    SemaRef.AddInitializerToDecl(UBDecl, LastIteration.get(),
                                 /*DirectInit*/ false);

    // A 32-bit variable-flag where runtime returns 1 for the last iteration.
    // This will be used to implement clause 'lastprivate'.
    QualType Int32Ty = SemaRef.Context.getIntTypeForBitwidth(32, true);
    VarDecl *ILDecl = buildVarDecl(SemaRef, InitLoc, Int32Ty, ".omp.is_last");
    IL = buildDeclRefExpr(SemaRef, ILDecl, Int32Ty, InitLoc);
    SemaRef.AddInitializerToDecl(ILDecl,
                                 SemaRef.ActOnIntegerConstant(InitLoc, 0).get(),
                                 /*DirectInit*/ false);

    // Stride variable returned by runtime (we initialize it to 1 by default).
    VarDecl *STDecl =
        buildVarDecl(SemaRef, InitLoc, StrideVType, ".omp.stride");
    ST = buildDeclRefExpr(SemaRef, STDecl, StrideVType, InitLoc);
    SemaRef.AddInitializerToDecl(STDecl,
                                 SemaRef.ActOnIntegerConstant(InitLoc, 1).get(),
                                 /*DirectInit*/ false);

    // Build expression: UB = min(UB, LastIteration)
    // It is necessary for CodeGen of directives with static scheduling.
    ExprResult IsUBGreater = SemaRef.BuildBinOp(CurScope, InitLoc, BO_GT,
                                                UB.get(), LastIteration.get());
    ExprResult CondOp = SemaRef.ActOnConditionalOp(
        LastIteration.get()->getExprLoc(), InitLoc, IsUBGreater.get(),
        LastIteration.get(), UB.get());
    EUB = SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, UB.get(),
                             CondOp.get());
    EUB = SemaRef.ActOnFinishFullExpr(EUB.get());

    // 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
    // enclosing region. E.g. in 'distribute parallel for' the bounds obtained
    // by scheduling 'distribute' have to be passed to the schedule of 'for'.
    if (isOpenMPLoopBoundSharingDirective(DKind)) {
      // Lower bound variable, initialized with zero.
      VarDecl *CombLBDecl =
          buildVarDecl(SemaRef, InitLoc, VType, ".omp.comb.lb");
      CombLB = buildDeclRefExpr(SemaRef, CombLBDecl, VType, InitLoc);
      SemaRef.AddInitializerToDecl(
          CombLBDecl, SemaRef.ActOnIntegerConstant(InitLoc, 0).get(),
          /*DirectInit*/ false);

      // Upper bound variable, initialized with last iteration number.
      VarDecl *CombUBDecl =
          buildVarDecl(SemaRef, InitLoc, VType, ".omp.comb.ub");
      CombUB = buildDeclRefExpr(SemaRef, CombUBDecl, VType, InitLoc);
      SemaRef.AddInitializerToDecl(CombUBDecl, LastIteration.get(),
                                   /*DirectInit*/ false);

      ExprResult CombIsUBGreater = SemaRef.BuildBinOp(
          CurScope, InitLoc, BO_GT, CombUB.get(), LastIteration.get());
      ExprResult CombCondOp =
          SemaRef.ActOnConditionalOp(InitLoc, InitLoc, CombIsUBGreater.get(),
                                     LastIteration.get(), CombUB.get());
      CombEUB = SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, CombUB.get(),
                                   CombCondOp.get());
      CombEUB = SemaRef.ActOnFinishFullExpr(CombEUB.get());

      const CapturedDecl *CD = cast<CapturedStmt>(AStmt)->getCapturedDecl();
      // We expect to have at least 2 more parameters than the 'parallel'
      // directive does - the lower and upper bounds of the previous schedule.
      assert(CD->getNumParams() >= 4 &&
             "Unexpected number of parameters in loop combined directive");

      // Set the proper type for the bounds given what we learned from the
      // enclosed loops.
      ImplicitParamDecl *PrevLBDecl = CD->getParam(/*PrevLB=*/2);
      ImplicitParamDecl *PrevUBDecl = CD->getParam(/*PrevUB=*/3);

      // Previous lower and upper bounds are obtained from the region
      // parameters.
      PrevLB =
          buildDeclRefExpr(SemaRef, PrevLBDecl, PrevLBDecl->getType(), InitLoc);
      PrevUB =
          buildDeclRefExpr(SemaRef, PrevUBDecl, PrevUBDecl->getType(), InitLoc);
    }
  }

  // Build the iteration variable and its initialization before loop.
  ExprResult IV;
  ExprResult Init, CombInit;
  {
    VarDecl *IVDecl = buildVarDecl(SemaRef, InitLoc, RealVType, ".omp.iv");
    IV = buildDeclRefExpr(SemaRef, IVDecl, RealVType, InitLoc);
    Expr *RHS =
        (isOpenMPWorksharingDirective(DKind) ||
         isOpenMPTaskLoopDirective(DKind) || isOpenMPDistributeDirective(DKind))
            ? LB.get()
            : SemaRef.ActOnIntegerConstant(SourceLocation(), 0).get();
    Init = SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, IV.get(), RHS);
    Init = SemaRef.ActOnFinishFullExpr(Init.get());

    if (isOpenMPLoopBoundSharingDirective(DKind)) {
      Expr *CombRHS =
          (isOpenMPWorksharingDirective(DKind) ||
           isOpenMPTaskLoopDirective(DKind) ||
           isOpenMPDistributeDirective(DKind))
              ? CombLB.get()
              : SemaRef.ActOnIntegerConstant(SourceLocation(), 0).get();
      CombInit =
          SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, IV.get(), CombRHS);
      CombInit = SemaRef.ActOnFinishFullExpr(CombInit.get());
    }
  }

  // Loop condition (IV < NumIterations) or (IV <= UB) for worksharing loops.
  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 CombCond;
  if (isOpenMPLoopBoundSharingDirective(DKind)) {
    CombCond =
        SemaRef.BuildBinOp(CurScope, CondLoc, BO_LE, IV.get(), CombUB.get());
  }
  // Loop increment (IV = IV + 1)
  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());
  if (!Inc.isUsable())
    return 0;

  // Increments for worksharing loops (LB = LB + ST; UB = UB + ST).
  // Used for directives with static scheduling.
  // In combined construct, add combined version that use CombLB and CombUB
  // base variables for the update
  ExprResult NextLB, NextUB, CombNextLB, CombNextUB;
  if (isOpenMPWorksharingDirective(DKind) || isOpenMPTaskLoopDirective(DKind) ||
      isOpenMPDistributeDirective(DKind)) {
    // LB + ST
    NextLB = SemaRef.BuildBinOp(CurScope, IncLoc, BO_Add, LB.get(), ST.get());
    if (!NextLB.isUsable())
      return 0;
    // LB = LB + ST
    NextLB =
        SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, LB.get(), NextLB.get());
    NextLB = SemaRef.ActOnFinishFullExpr(NextLB.get());
    if (!NextLB.isUsable())
      return 0;
    // UB + ST
    NextUB = SemaRef.BuildBinOp(CurScope, IncLoc, BO_Add, UB.get(), ST.get());
    if (!NextUB.isUsable())
      return 0;
    // UB = UB + ST
    NextUB =
        SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, UB.get(), NextUB.get());
    NextUB = SemaRef.ActOnFinishFullExpr(NextUB.get());
    if (!NextUB.isUsable())
      return 0;
    if (isOpenMPLoopBoundSharingDirective(DKind)) {
      CombNextLB =
          SemaRef.BuildBinOp(CurScope, IncLoc, BO_Add, CombLB.get(), ST.get());
      if (!NextLB.isUsable())
        return 0;
      // LB = LB + ST
      CombNextLB = SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, CombLB.get(),
                                      CombNextLB.get());
      CombNextLB = SemaRef.ActOnFinishFullExpr(CombNextLB.get());
      if (!CombNextLB.isUsable())
        return 0;
      // UB + ST
      CombNextUB =
          SemaRef.BuildBinOp(CurScope, IncLoc, BO_Add, CombUB.get(), ST.get());
      if (!CombNextUB.isUsable())
        return 0;
      // UB = UB + ST
      CombNextUB = SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, CombUB.get(),
                                      CombNextUB.get());
      CombNextUB = SemaRef.ActOnFinishFullExpr(CombNextUB.get());
      if (!CombNextUB.isUsable())
        return 0;
    }
  }

  // Create increment expression for distribute loop when combined in a same
  // 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->getBeginLoc();
  ExprResult DistCond, DistInc, PrevEUB;
  if (isOpenMPLoopBoundSharingDirective(DKind)) {
    DistCond = SemaRef.BuildBinOp(CurScope, CondLoc, BO_LE, IV.get(), UB.get());
    assert(DistCond.isUsable() && "distribute cond expr was not built");

    DistInc =
        SemaRef.BuildBinOp(CurScope, DistIncLoc, BO_Add, IV.get(), ST.get());
    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());
    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->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());
  }

  // Build updates and final values of the loop counters.
  bool HasErrors = false;
  Built.Counters.resize(NestedLoopCount);
  Built.Inits.resize(NestedLoopCount);
  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) {
      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);
      if (!Iter.isUsable()) {
        HasErrors = true;
        break;
      }

      // Build update: IS.CounterVar(Private) = IS.Start + Iter * IS.Step
      auto *VD = cast<VarDecl>(cast<DeclRefExpr>(IS.CounterVar)->getDecl());
      DeclRefExpr *CounterVar = buildDeclRefExpr(
          SemaRef, VD, IS.CounterVar->getType(), IS.CounterVar->getExprLoc(),
          /*RefersToCapture=*/true);
      ExprResult Init = buildCounterInit(SemaRef, CurScope, UpdLoc, CounterVar,
                                         IS.CounterInit, Captures);
      if (!Init.isUsable()) {
        HasErrors = true;
        break;
      }
      ExprResult Update = buildCounterUpdate(
          SemaRef, CurScope, UpdLoc, CounterVar, IS.CounterInit, Iter,
          IS.CounterStep, IS.Subtract, &Captures);
      if (!Update.isUsable()) {
        HasErrors = true;
        break;
      }

      // Build final: IS.CounterVar = IS.Start + IS.NumIters * IS.Step
      ExprResult Final = buildCounterUpdate(
          SemaRef, CurScope, UpdLoc, CounterVar, IS.CounterInit,
          IS.NumIterations, IS.CounterStep, IS.Subtract, &Captures);
      if (!Final.isUsable()) {
        HasErrors = true;
        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;
      }
      // Save results
      Built.Counters[Cnt] = IS.CounterVar;
      Built.PrivateCounters[Cnt] = IS.PrivateCounterVar;
      Built.Inits[Cnt] = Init.get();
      Built.Updates[Cnt] = Update.get();
      Built.Finals[Cnt] = Final.get();
    }
  }

  if (HasErrors)
    return 0;

  // Save results
  Built.IterationVarRef = IV.get();
  Built.LastIteration = LastIteration.get();
  Built.NumIterations = NumIterations.get();
  Built.CalcLastIteration =
      SemaRef.ActOnFinishFullExpr(CalcLastIteration.get()).get();
  Built.PreCond = PreCond.get();
  Built.PreInits = buildPreInits(C, Captures);
  Built.Cond = Cond.get();
  Built.Init = Init.get();
  Built.Inc = Inc.get();
  Built.LB = LB.get();
  Built.UB = UB.get();
  Built.IL = IL.get();
  Built.ST = ST.get();
  Built.EUB = EUB.get();
  Built.NLB = NextLB.get();
  Built.NUB = NextUB.get();
  Built.PrevLB = PrevLB.get();
  Built.PrevUB = PrevUB.get();
  Built.DistInc = DistInc.get();
  Built.PrevEUB = PrevEUB.get();
  Built.DistCombinedFields.LB = CombLB.get();
  Built.DistCombinedFields.UB = CombUB.get();
  Built.DistCombinedFields.EUB = CombEUB.get();
  Built.DistCombinedFields.Init = CombInit.get();
  Built.DistCombinedFields.Cond = CombCond.get();
  Built.DistCombinedFields.NLB = CombNextLB.get();
  Built.DistCombinedFields.NUB = CombNextUB.get();

  return NestedLoopCount;
}

static Expr *getCollapseNumberExpr(ArrayRef<OMPClause *> Clauses) {
  auto CollapseClauses =
      OMPExecutableDirective::getClausesOfKind<OMPCollapseClause>(Clauses);
  if (CollapseClauses.begin() != CollapseClauses.end())
    return (*CollapseClauses.begin())->getNumForLoops();
  return nullptr;
}

static Expr *getOrderedNumberExpr(ArrayRef<OMPClause *> Clauses) {
  auto OrderedClauses =
      OMPExecutableDirective::getClausesOfKind<OMPOrderedClause>(Clauses);
  if (OrderedClauses.begin() != OrderedClauses.end())
    return (*OrderedClauses.begin())->getNumForLoops();
  return nullptr;
}

static bool checkSimdlenSafelenSpecified(Sema &S,
                                         const ArrayRef<OMPClause *> Clauses) {
  const OMPSafelenClause *Safelen = nullptr;
  const OMPSimdlenClause *Simdlen = nullptr;

  for (const OMPClause *Clause : Clauses) {
    if (Clause->getClauseKind() == OMPC_safelen)
      Safelen = cast<OMPSafelenClause>(Clause);
    else if (Clause->getClauseKind() == OMPC_simdlen)
      Simdlen = cast<OMPSimdlenClause>(Clause);
    if (Safelen && Simdlen)
      break;
  }

  if (Simdlen && Safelen) {
    llvm::APSInt SimdlenRes, SafelenRes;
    const Expr *SimdlenLength = Simdlen->getSimdlen();
    const Expr *SafelenLength = Safelen->getSafelen();
    if (SimdlenLength->isValueDependent() || SimdlenLength->isTypeDependent() ||
        SimdlenLength->isInstantiationDependent() ||
        SimdlenLength->containsUnexpandedParameterPack())
      return false;
    if (SafelenLength->isValueDependent() || SafelenLength->isTypeDependent() ||
        SafelenLength->isInstantiationDependent() ||
        SafelenLength->containsUnexpandedParameterPack())
      return false;
    SimdlenLength->EvaluateAsInt(SimdlenRes, S.Context);
    SafelenLength->EvaluateAsInt(SafelenRes, S.Context);
    // 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
    // parameter.
    if (SimdlenRes > SafelenRes) {
      S.Diag(SimdlenLength->getExprLoc(),
             diag::err_omp_wrong_simdlen_safelen_values)
          << SimdlenLength->getSourceRange() << SafelenLength->getSourceRange();
      return true;
    }
  }
  return false;
}

StmtResult
Sema::ActOnOpenMPSimdDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                               SourceLocation StartLoc, SourceLocation EndLoc,
                               VarsWithInheritedDSAType &VarsWithImplicitDSA) {
  if (!AStmt)
    return StmtError();

  assert(isa<CapturedStmt>(AStmt) && "Captured statement expected");
  OMPLoopDirective::HelperExprs B;
  // In presence of clause 'collapse' or 'ordered' with number of loops, it will
  // define the nested loops number.
  unsigned NestedLoopCount = checkOpenMPLoop(
      OMPD_simd, getCollapseNumberExpr(Clauses), getOrderedNumberExpr(Clauses),
      AStmt, *this, *DSAStack, VarsWithImplicitDSA, B);
  if (NestedLoopCount == 0)
    return StmtError();

  assert((CurContext->isDependentContext() || B.builtAll()) &&
         "omp simd loop exprs were not built");

  if (!CurContext->isDependentContext()) {
    // Finalize the clauses that need pre-built expressions for CodeGen.
    for (OMPClause *C : Clauses) {
      if (auto *LC = dyn_cast<OMPLinearClause>(C))
        if (FinishOpenMPLinearClause(*LC, cast<DeclRefExpr>(B.IterationVarRef),
                                     B.NumIterations, *this, CurScope,
                                     DSAStack))
          return StmtError();
    }
  }

  if (checkSimdlenSafelenSpecified(*this, Clauses))
    return StmtError();

  setFunctionHasBranchProtectedScope();
  return OMPSimdDirective::Create(Context, StartLoc, EndLoc, NestedLoopCount,
                                  Clauses, AStmt, B);
}

StmtResult
Sema::ActOnOpenMPForDirective(ArrayRef<OMPClause *> Clauses, Stmt *AStmt,
                              SourceLocation StartLoc, SourceLocation EndLoc,
                              VarsWithInheritedDSAType &VarsWithImplicitDSA) {
  if (!AStmt)
    return StmtError();

  assert(isa<CapturedStmt>(AStmt) && "Captured statement expected");
  OMPLoopDirective::HelperExprs B;
  // In presence of clause 'collapse' or 'ordered' with number of loops, it will
  // define the nested loops number.
  unsigned NestedLoopCount = checkOpenMPLoop(
      OMPD_for, getCollapseNumberExpr(Clauses), getOrderedNumberExpr(Clauses),
      AStmt, *this, *DSAStack, VarsWithImplicitDSA, B);
  if (NestedLoopCount == 0)
    return StmtError();

  assert((CurContext->isDependentContext() || B.builtAll()) &&
         "omp for loop exprs were not built");

  if (!CurContext->isDependentContext()) {
    // Finalize the clauses that need pre-built expressions for CodeGen.
    for (OMPClause *C : Clauses) {
      if (auto *LC = dyn_cast<OMPLinearClause>(C))
        if (FinishOpenMPLinearClause(*LC, cast<DeclRefExpr>(B.IterationVarRef),
                                     B.NumIterations, *this, CurScope,
                                     DSAStack))
          return StmtError();
    }
  }

  setFunctionHasBranchProtectedScope();
  return OMPForDirective::Create(Context, StartLoc, EndLoc, NestedLoopCount,
                                 Clauses, AStmt, B, DSAStack->isCancelRegion());
}

StmtResult Sema::ActOnOpenMPForSimdDirective(
    ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
    SourceLocation EndLoc, VarsWithInheritedDSAType &VarsWithImplicitDSA) {
  if (!AStmt)
    return StmtError();

  assert(isa<CapturedStmt>(AStmt) && "Captured statement expected");
  OMPLoopDirective::HelperExprs B;
  // In presence of clause 'collapse' or 'ordered' with number of loops, it will
  // define the nested loops number.
  unsigned NestedLoopCount =
      checkOpenMPLoop(OMPD_for_simd, getCollapseNumberExpr(Clauses),
                      getOrderedNumberExpr(Clauses), AStmt, *this, *DSAStack,
                      VarsWithImplicitDSA, B);
  if (NestedLoopCount == 0)
    return StmtError();

  assert((CurContext->isDependentContext() || B.builtAll()) &&
         "omp for simd loop exprs were not built");

  if (!CurContext->isDependentContext()) {
    // Finalize the clauses that need pre-built expressions for CodeGen.
    for (OMPClause *C : Clauses) {
      if (auto *LC = dyn_cast<OMPLinearClause>(C))
        if (FinishOpenMPLinearClause(*LC, cast<DeclRefExpr>(B.IterationVarRef),
                                     B.NumIterations, *this, CurScope,
                                     DSAStack))
          return StmtError();
    }
  }

  if (checkSimdlenSafelenSpecified(*this, Clauses))
    return StmtError();

  setFunctionHasBranchProtectedScope();
  return OMPForSimdDirective::Create(Context, StartLoc, EndLoc, NestedLoopCount,
                                     Clauses, AStmt, B);
}

StmtResult Sema::ActOnOpenMPSectionsDirective(ArrayRef<OMPClause *> Clauses,
                                              Stmt *AStmt,
                                              SourceLocation StartLoc,
                                              SourceLocation EndLoc) {
  if (!AStmt)
    return StmtError();

  assert(isa<CapturedStmt>(AStmt) && "Captured statement expected");
  auto BaseStmt = AStmt;
  while (auto *CS = dyn_cast_or_null<CapturedStmt>(BaseStmt))
    BaseStmt = CS->getCapturedStmt();
  if (auto *C = dyn_cast_or_null<CompoundStmt>(BaseStmt)) {
    auto S = C->children();
    if (S.begin() == S.end())
      return StmtError();
    // All associated statements must be '#pragma omp section' except for
    // the first one.
    for (Stmt *SectionStmt : llvm::make_range(std::next(S.begin()), S.end())) {
      if (!SectionStmt || !isa<OMPSectionDirective>(SectionStmt)) {
        if (SectionStmt)
          Diag(SectionStmt->getBeginLoc(),
               diag::err_omp_sections_substmt_not_section);
        return StmtError();
      }
      cast<OMPSectionDirective>(SectionStmt)
          ->setHasCancel(DSAStack->isCancelRegion());
    }
  } else {
    Diag(AStmt->getBeginLoc(), diag::err_omp_sections_not_compound_stmt);
    return StmtError();
  }

  setFunctionHasBranchProtectedScope();

  return OMPSectionsDirective::Create(Context, StartLoc, EndLoc, Clauses, AStmt,
                                      DSAStack->isCancelRegion());
}

StmtResult Sema::ActOnOpenMPSectionDirective(Stmt *AStmt,
                                             SourceLocation StartLoc,
                                             SourceLocation EndLoc) {
  if (!AStmt)
    return StmtError();

  assert(isa<CapturedStmt>(AStmt) && "Captured statement expected");

  setFunctionHasBranchProtectedScope();
  DSAStack->setParentCancelRegion(DSAStack->isCancelRegion());

  return OMPSectionDirective::Create(Context, StartLoc, EndLoc, AStmt,
                                     DSAStack->isCancelRegion());
}

StmtResult Sema::ActOnOpenMPSingleDirective(ArrayRef<OMPClause *> Clauses,
                                            Stmt *AStmt,
                                            SourceLocation StartLoc,
                                            SourceLocation EndLoc) {
  if (!AStmt)
    return StmtError();

  assert(isa<CapturedStmt>(AStmt) && "Captured statement expected");

  setFunctionHasBranchProtectedScope();

  // OpenMP [2.7.3, single Construct, Restrictions]
  // The copyprivate clause must not be used with the nowait clause.
  const OMPClause *Nowait = nullptr;
  const OMPClause *Copyprivate = nullptr;
  for (const OMPClause *Clause : Clauses) {
    if (Clause->getClauseKind() == OMPC_nowait)
      Nowait = Clause;
    else if (Clause->getClauseKind() == OMPC_copyprivate)
      Copyprivate = Clause;
    if (Copyprivate && Nowait) {
      Diag(Copyprivate->getBeginLoc(),