diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.cpp b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
index a2ea0de..76f4467 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -697,6 +697,400 @@
   }
 }
 
+/// Check if the combiner is a call to UDR combiner and if it is so return the
+/// UDR decl used for reduction.
+static const OMPDeclareReductionDecl *
+getReductionInit(const Expr *ReductionOp) {
+  if (auto *CE = dyn_cast<CallExpr>(ReductionOp))
+    if (auto *OVE = dyn_cast<OpaqueValueExpr>(CE->getCallee()))
+      if (auto *DRE =
+              dyn_cast<DeclRefExpr>(OVE->getSourceExpr()->IgnoreImpCasts()))
+        if (auto *DRD = dyn_cast<OMPDeclareReductionDecl>(DRE->getDecl()))
+          return DRD;
+  return nullptr;
+}
+
+static void emitInitWithReductionInitializer(CodeGenFunction &CGF,
+                                             const OMPDeclareReductionDecl *DRD,
+                                             const Expr *InitOp,
+                                             Address Private, Address Original,
+                                             QualType Ty) {
+  if (DRD->getInitializer()) {
+    std::pair<llvm::Function *, llvm::Function *> Reduction =
+        CGF.CGM.getOpenMPRuntime().getUserDefinedReduction(DRD);
+    auto *CE = cast<CallExpr>(InitOp);
+    auto *OVE = cast<OpaqueValueExpr>(CE->getCallee());
+    const Expr *LHS = CE->getArg(/*Arg=*/0)->IgnoreParenImpCasts();
+    const Expr *RHS = CE->getArg(/*Arg=*/1)->IgnoreParenImpCasts();
+    auto *LHSDRE = cast<DeclRefExpr>(cast<UnaryOperator>(LHS)->getSubExpr());
+    auto *RHSDRE = cast<DeclRefExpr>(cast<UnaryOperator>(RHS)->getSubExpr());
+    CodeGenFunction::OMPPrivateScope PrivateScope(CGF);
+    PrivateScope.addPrivate(cast<VarDecl>(LHSDRE->getDecl()),
+                            [=]() -> Address { return Private; });
+    PrivateScope.addPrivate(cast<VarDecl>(RHSDRE->getDecl()),
+                            [=]() -> Address { return Original; });
+    (void)PrivateScope.Privatize();
+    RValue Func = RValue::get(Reduction.second);
+    CodeGenFunction::OpaqueValueMapping Map(CGF, OVE, Func);
+    CGF.EmitIgnoredExpr(InitOp);
+  } else {
+    llvm::Constant *Init = CGF.CGM.EmitNullConstant(Ty);
+    auto *GV = new llvm::GlobalVariable(
+        CGF.CGM.getModule(), Init->getType(), /*isConstant=*/true,
+        llvm::GlobalValue::PrivateLinkage, Init, ".init");
+    LValue LV = CGF.MakeNaturalAlignAddrLValue(GV, Ty);
+    RValue InitRVal;
+    switch (CGF.getEvaluationKind(Ty)) {
+    case TEK_Scalar:
+      InitRVal = CGF.EmitLoadOfLValue(LV, SourceLocation());
+      break;
+    case TEK_Complex:
+      InitRVal =
+          RValue::getComplex(CGF.EmitLoadOfComplex(LV, SourceLocation()));
+      break;
+    case TEK_Aggregate:
+      InitRVal = RValue::getAggregate(LV.getAddress());
+      break;
+    }
+    OpaqueValueExpr OVE(SourceLocation(), Ty, VK_RValue);
+    CodeGenFunction::OpaqueValueMapping OpaqueMap(CGF, &OVE, InitRVal);
+    CGF.EmitAnyExprToMem(&OVE, Private, Ty.getQualifiers(),
+                         /*IsInitializer=*/false);
+  }
+}
+
+/// \brief Emit initialization of arrays of complex types.
+/// \param DestAddr Address of the array.
+/// \param Type Type of array.
+/// \param Init Initial expression of array.
+/// \param SrcAddr Address of the original array.
+static void EmitOMPAggregateInit(CodeGenFunction &CGF, Address DestAddr,
+                                 QualType Type, const Expr *Init,
+                                 Address SrcAddr = Address::invalid()) {
+  auto *DRD = getReductionInit(Init);
+  // Perform element-by-element initialization.
+  QualType ElementTy;
+
+  // Drill down to the base element type on both arrays.
+  auto ArrayTy = Type->getAsArrayTypeUnsafe();
+  auto NumElements = CGF.emitArrayLength(ArrayTy, ElementTy, DestAddr);
+  DestAddr =
+      CGF.Builder.CreateElementBitCast(DestAddr, DestAddr.getElementType());
+  if (DRD)
+    SrcAddr =
+        CGF.Builder.CreateElementBitCast(SrcAddr, DestAddr.getElementType());
+
+  llvm::Value *SrcBegin = nullptr;
+  if (DRD)
+    SrcBegin = SrcAddr.getPointer();
+  auto DestBegin = DestAddr.getPointer();
+  // Cast from pointer to array type to pointer to single element.
+  auto DestEnd = CGF.Builder.CreateGEP(DestBegin, NumElements);
+  // The basic structure here is a while-do loop.
+  auto BodyBB = CGF.createBasicBlock("omp.arrayinit.body");
+  auto DoneBB = CGF.createBasicBlock("omp.arrayinit.done");
+  auto IsEmpty =
+      CGF.Builder.CreateICmpEQ(DestBegin, DestEnd, "omp.arrayinit.isempty");
+  CGF.Builder.CreateCondBr(IsEmpty, DoneBB, BodyBB);
+
+  // Enter the loop body, making that address the current address.
+  auto EntryBB = CGF.Builder.GetInsertBlock();
+  CGF.EmitBlock(BodyBB);
+
+  CharUnits ElementSize = CGF.getContext().getTypeSizeInChars(ElementTy);
+
+  llvm::PHINode *SrcElementPHI = nullptr;
+  Address SrcElementCurrent = Address::invalid();
+  if (DRD) {
+    SrcElementPHI = CGF.Builder.CreatePHI(SrcBegin->getType(), 2,
+                                          "omp.arraycpy.srcElementPast");
+    SrcElementPHI->addIncoming(SrcBegin, EntryBB);
+    SrcElementCurrent =
+        Address(SrcElementPHI,
+                SrcAddr.getAlignment().alignmentOfArrayElement(ElementSize));
+  }
+  llvm::PHINode *DestElementPHI = CGF.Builder.CreatePHI(
+      DestBegin->getType(), 2, "omp.arraycpy.destElementPast");
+  DestElementPHI->addIncoming(DestBegin, EntryBB);
+  Address DestElementCurrent =
+      Address(DestElementPHI,
+              DestAddr.getAlignment().alignmentOfArrayElement(ElementSize));
+
+  // Emit copy.
+  {
+    CodeGenFunction::RunCleanupsScope InitScope(CGF);
+    if (DRD && (DRD->getInitializer() || !Init)) {
+      emitInitWithReductionInitializer(CGF, DRD, Init, DestElementCurrent,
+                                       SrcElementCurrent, ElementTy);
+    } else
+      CGF.EmitAnyExprToMem(Init, DestElementCurrent, ElementTy.getQualifiers(),
+                           /*IsInitializer=*/false);
+  }
+
+  if (DRD) {
+    // Shift the address forward by one element.
+    auto SrcElementNext = CGF.Builder.CreateConstGEP1_32(
+        SrcElementPHI, /*Idx0=*/1, "omp.arraycpy.dest.element");
+    SrcElementPHI->addIncoming(SrcElementNext, CGF.Builder.GetInsertBlock());
+  }
+
+  // Shift the address forward by one element.
+  auto DestElementNext = CGF.Builder.CreateConstGEP1_32(
+      DestElementPHI, /*Idx0=*/1, "omp.arraycpy.dest.element");
+  // Check whether we've reached the end.
+  auto Done =
+      CGF.Builder.CreateICmpEQ(DestElementNext, DestEnd, "omp.arraycpy.done");
+  CGF.Builder.CreateCondBr(Done, DoneBB, BodyBB);
+  DestElementPHI->addIncoming(DestElementNext, CGF.Builder.GetInsertBlock());
+
+  // Done.
+  CGF.EmitBlock(DoneBB, /*IsFinished=*/true);
+}
+
+LValue ReductionCodeGen::emitSharedLValue(CodeGenFunction &CGF, const Expr *E) {
+  if (const auto *OASE = dyn_cast<OMPArraySectionExpr>(E))
+    return CGF.EmitOMPArraySectionExpr(OASE);
+  if (const auto *ASE = dyn_cast<ArraySubscriptExpr>(E))
+    return CGF.EmitLValue(ASE);
+  auto *OrigVD = cast<VarDecl>(cast<DeclRefExpr>(E)->getDecl());
+  DeclRefExpr DRE(const_cast<VarDecl *>(OrigVD),
+                  CGF.CapturedStmtInfo &&
+                      CGF.CapturedStmtInfo->lookup(OrigVD) != nullptr,
+                  E->getType(), VK_LValue, E->getExprLoc());
+  // Store the address of the original variable associated with the LHS
+  // implicit variable.
+  return CGF.EmitLValue(&DRE);
+}
+
+LValue ReductionCodeGen::emitSharedLValueUB(CodeGenFunction &CGF,
+                                            const Expr *E) {
+  if (const auto *OASE = dyn_cast<OMPArraySectionExpr>(E))
+    return CGF.EmitOMPArraySectionExpr(OASE, /*IsLowerBound=*/false);
+  return LValue();
+}
+
+void ReductionCodeGen::emitAggregateInitialization(CodeGenFunction &CGF,
+                                                   unsigned N,
+                                                   Address PrivateAddr,
+                                                   LValue SharedLVal) {
+  // Emit VarDecl with copy init for arrays.
+  // Get the address of the original variable captured in current
+  // captured region.
+  auto *PrivateVD =
+      cast<VarDecl>(cast<DeclRefExpr>(ClausesData[N].Private)->getDecl());
+  auto *DRD = getReductionInit(ClausesData[N].ReductionOp);
+  EmitOMPAggregateInit(CGF, PrivateAddr, PrivateVD->getType(),
+                       DRD ? ClausesData[N].ReductionOp : PrivateVD->getInit(),
+                       SharedLVal.getAddress());
+}
+
+ReductionCodeGen::ReductionCodeGen(ArrayRef<const Expr *> Shareds,
+                                   ArrayRef<const Expr *> Privates,
+                                   ArrayRef<const Expr *> ReductionOps) {
+  ClausesData.reserve(Shareds.size());
+  SharedAddresses.reserve(Shareds.size());
+  Sizes.reserve(Shareds.size());
+  auto IPriv = Privates.begin();
+  auto IRed = ReductionOps.begin();
+  for (const auto *Ref : Shareds) {
+    ClausesData.emplace_back(Ref, *IPriv, *IRed);
+    std::advance(IPriv, 1);
+    std::advance(IRed, 1);
+  }
+}
+
+void ReductionCodeGen::emitSharedLValue(CodeGenFunction &CGF, unsigned N) {
+  assert(SharedAddresses.size() == N &&
+         "Number of generated lvalues must be exactly N.");
+  SharedAddresses.emplace_back(emitSharedLValue(CGF, ClausesData[N].Ref),
+                               emitSharedLValueUB(CGF, ClausesData[N].Ref));
+}
+
+void ReductionCodeGen::emitAggregateType(CodeGenFunction &CGF, unsigned N) {
+  auto *PrivateVD =
+      cast<VarDecl>(cast<DeclRefExpr>(ClausesData[N].Private)->getDecl());
+  QualType PrivateType = PrivateVD->getType();
+  bool AsArraySection = isa<OMPArraySectionExpr>(ClausesData[N].Ref);
+  if (!AsArraySection && !PrivateType->isVariablyModifiedType()) {
+    Sizes.emplace_back(nullptr);
+    return;
+  }
+  llvm::Value *Size;
+  if (AsArraySection) {
+    Size = CGF.Builder.CreatePtrDiff(SharedAddresses[N].second.getPointer(),
+                                     SharedAddresses[N].first.getPointer());
+    Size = CGF.Builder.CreateNUWAdd(
+        Size, llvm::ConstantInt::get(Size->getType(), /*V=*/1));
+  } else {
+    Size = CGF.getTypeSize(
+        SharedAddresses[N].first.getType().getNonReferenceType());
+  }
+  Sizes.emplace_back(Size);
+  CodeGenFunction::OpaqueValueMapping OpaqueMap(
+      CGF,
+      cast<OpaqueValueExpr>(
+          CGF.getContext().getAsVariableArrayType(PrivateType)->getSizeExpr()),
+      RValue::get(Size));
+  CGF.EmitVariablyModifiedType(PrivateType);
+}
+
+void ReductionCodeGen::emitAggregateType(CodeGenFunction &CGF, unsigned N,
+                                         llvm::Value *Size) {
+  auto *PrivateVD =
+      cast<VarDecl>(cast<DeclRefExpr>(ClausesData[N].Private)->getDecl());
+  QualType PrivateType = PrivateVD->getType();
+  bool AsArraySection = isa<OMPArraySectionExpr>(ClausesData[N].Ref);
+  if (!AsArraySection && !PrivateType->isVariablyModifiedType()) {
+    assert(!Size && !Sizes[N] &&
+           "Size should be nullptr for non-variably modified redution "
+           "items.");
+    return;
+  }
+  CodeGenFunction::OpaqueValueMapping OpaqueMap(
+      CGF,
+      cast<OpaqueValueExpr>(
+          CGF.getContext().getAsVariableArrayType(PrivateType)->getSizeExpr()),
+      RValue::get(Size));
+  CGF.EmitVariablyModifiedType(PrivateType);
+}
+
+void ReductionCodeGen::emitInitialization(
+    CodeGenFunction &CGF, unsigned N, Address PrivateAddr, LValue SharedLVal,
+    llvm::function_ref<bool(CodeGenFunction &)> DefaultInit) {
+  assert(SharedAddresses.size() > N && "No variable was generated");
+  auto *PrivateVD =
+      cast<VarDecl>(cast<DeclRefExpr>(ClausesData[N].Private)->getDecl());
+  auto *DRD = getReductionInit(ClausesData[N].ReductionOp);
+  QualType PrivateType = PrivateVD->getType();
+  PrivateAddr = CGF.Builder.CreateElementBitCast(
+      PrivateAddr, CGF.ConvertTypeForMem(PrivateType));
+  QualType SharedType = SharedAddresses[N].first.getType();
+  SharedLVal = CGF.MakeAddrLValue(
+      CGF.Builder.CreateElementBitCast(SharedLVal.getAddress(),
+                                       CGF.ConvertTypeForMem(SharedType)),
+      SharedType, SharedAddresses[N].first.getBaseInfo());
+  if (isa<OMPArraySectionExpr>(ClausesData[N].Ref) ||
+      CGF.getContext().getAsArrayType(PrivateVD->getType())) {
+    emitAggregateInitialization(CGF, N, PrivateAddr, SharedLVal);
+  } else if (DRD && (DRD->getInitializer() || !PrivateVD->hasInit())) {
+    emitInitWithReductionInitializer(CGF, DRD, ClausesData[N].ReductionOp,
+                                     PrivateAddr, SharedLVal.getAddress(),
+                                     SharedLVal.getType());
+  } else if (!DefaultInit(CGF) && PrivateVD->hasInit() &&
+             !CGF.isTrivialInitializer(PrivateVD->getInit())) {
+    CGF.EmitAnyExprToMem(PrivateVD->getInit(), PrivateAddr,
+                         PrivateVD->getType().getQualifiers(),
+                         /*IsInitializer=*/false);
+  }
+}
+
+bool ReductionCodeGen::needCleanups(unsigned N) {
+  auto *PrivateVD =
+      cast<VarDecl>(cast<DeclRefExpr>(ClausesData[N].Private)->getDecl());
+  QualType PrivateType = PrivateVD->getType();
+  QualType::DestructionKind DTorKind = PrivateType.isDestructedType();
+  return DTorKind != QualType::DK_none;
+}
+
+void ReductionCodeGen::emitCleanups(CodeGenFunction &CGF, unsigned N,
+                                    Address PrivateAddr) {
+  auto *PrivateVD =
+      cast<VarDecl>(cast<DeclRefExpr>(ClausesData[N].Private)->getDecl());
+  QualType PrivateType = PrivateVD->getType();
+  QualType::DestructionKind DTorKind = PrivateType.isDestructedType();
+  if (needCleanups(N)) {
+    PrivateAddr = CGF.Builder.CreateElementBitCast(
+        PrivateAddr, CGF.ConvertTypeForMem(PrivateType));
+    CGF.pushDestroy(DTorKind, PrivateAddr, PrivateType);
+  }
+}
+
+static LValue loadToBegin(CodeGenFunction &CGF, QualType BaseTy, QualType ElTy,
+                          LValue BaseLV) {
+  BaseTy = BaseTy.getNonReferenceType();
+  while ((BaseTy->isPointerType() || BaseTy->isReferenceType()) &&
+         !CGF.getContext().hasSameType(BaseTy, ElTy)) {
+    if (auto *PtrTy = BaseTy->getAs<PointerType>())
+      BaseLV = CGF.EmitLoadOfPointerLValue(BaseLV.getAddress(), PtrTy);
+    else {
+      BaseLV = CGF.EmitLoadOfReferenceLValue(BaseLV.getAddress(),
+                                             BaseTy->castAs<ReferenceType>());
+    }
+    BaseTy = BaseTy->getPointeeType();
+  }
+  return CGF.MakeAddrLValue(
+      CGF.Builder.CreateElementBitCast(BaseLV.getAddress(),
+                                       CGF.ConvertTypeForMem(ElTy)),
+      BaseLV.getType(), BaseLV.getBaseInfo());
+}
+
+static Address castToBase(CodeGenFunction &CGF, QualType BaseTy, QualType ElTy,
+                          llvm::Type *BaseLVType, CharUnits BaseLVAlignment,
+                          llvm::Value *Addr) {
+  Address Tmp = Address::invalid();
+  Address TopTmp = Address::invalid();
+  Address MostTopTmp = Address::invalid();
+  BaseTy = BaseTy.getNonReferenceType();
+  while ((BaseTy->isPointerType() || BaseTy->isReferenceType()) &&
+         !CGF.getContext().hasSameType(BaseTy, ElTy)) {
+    Tmp = CGF.CreateMemTemp(BaseTy);
+    if (TopTmp.isValid())
+      CGF.Builder.CreateStore(Tmp.getPointer(), TopTmp);
+    else
+      MostTopTmp = Tmp;
+    TopTmp = Tmp;
+    BaseTy = BaseTy->getPointeeType();
+  }
+  llvm::Type *Ty = BaseLVType;
+  if (Tmp.isValid())
+    Ty = Tmp.getElementType();
+  Addr = CGF.Builder.CreatePointerBitCastOrAddrSpaceCast(Addr, Ty);
+  if (Tmp.isValid()) {
+    CGF.Builder.CreateStore(Addr, Tmp);
+    return MostTopTmp;
+  }
+  return Address(Addr, BaseLVAlignment);
+}
+
+Address ReductionCodeGen::adjustPrivateAddress(CodeGenFunction &CGF, unsigned N,
+                                               Address PrivateAddr) {
+  const DeclRefExpr *DE;
+  const VarDecl *OrigVD = nullptr;
+  if (auto *OASE = dyn_cast<OMPArraySectionExpr>(ClausesData[N].Ref)) {
+    auto *Base = OASE->getBase()->IgnoreParenImpCasts();
+    while (auto *TempOASE = dyn_cast<OMPArraySectionExpr>(Base))
+      Base = TempOASE->getBase()->IgnoreParenImpCasts();
+    while (auto *TempASE = dyn_cast<ArraySubscriptExpr>(Base))
+      Base = TempASE->getBase()->IgnoreParenImpCasts();
+    DE = cast<DeclRefExpr>(Base);
+    OrigVD = cast<VarDecl>(DE->getDecl());
+  } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(ClausesData[N].Ref)) {
+    auto *Base = ASE->getBase()->IgnoreParenImpCasts();
+    while (auto *TempASE = dyn_cast<ArraySubscriptExpr>(Base))
+      Base = TempASE->getBase()->IgnoreParenImpCasts();
+    DE = cast<DeclRefExpr>(Base);
+    OrigVD = cast<VarDecl>(DE->getDecl());
+  }
+  if (OrigVD) {
+    BaseDecls.emplace_back(OrigVD);
+    auto OriginalBaseLValue = CGF.EmitLValue(DE);
+    LValue BaseLValue =
+        loadToBegin(CGF, OrigVD->getType(), SharedAddresses[N].first.getType(),
+                    OriginalBaseLValue);
+    llvm::Value *Adjustment = CGF.Builder.CreatePtrDiff(
+        BaseLValue.getPointer(), SharedAddresses[N].first.getPointer());
+    llvm::Value *Ptr =
+        CGF.Builder.CreateGEP(PrivateAddr.getPointer(), Adjustment);
+    return castToBase(CGF, OrigVD->getType(),
+                      SharedAddresses[N].first.getType(),
+                      OriginalBaseLValue.getPointer()->getType(),
+                      OriginalBaseLValue.getAlignment(), Ptr);
+  }
+  BaseDecls.emplace_back(
+      cast<VarDecl>(cast<DeclRefExpr>(ClausesData[N].Ref)->getDecl()));
+  return PrivateAddr;
+}
+
 LValue CGOpenMPRegionInfo::getThreadIDVariableLValue(CodeGenFunction &CGF) {
   return CGF.EmitLoadOfPointerLValue(
       CGF.GetAddrOfLocalVar(getThreadIDVariable()),
diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.h b/clang/lib/CodeGen/CGOpenMPRuntime.h
index 6f460f1..a9b7ef7 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.h
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.h
@@ -105,6 +105,86 @@
   bool Nogroup = false;
 };
 
+/// Class intended to support codegen of all kind of the reduction clauses.
+class ReductionCodeGen {
+private:
+  /// Data requiored for codegen of reduction clauses.
+  struct ReductionData {
+    /// Reference to the original shared item.
+    const Expr *Ref = nullptr;
+    /// Helper expression for generation of private copy.
+    const Expr *Private = nullptr;
+    /// Helper expression for generation reduction operation.
+    const Expr *ReductionOp = nullptr;
+    ReductionData(const Expr *Ref, const Expr *Private, const Expr *ReductionOp)
+        : Ref(Ref), Private(Private), ReductionOp(ReductionOp) {}
+  };
+  /// List of reduction-based clauses.
+  SmallVector<ReductionData, 4> ClausesData;
+
+  /// List of addresses of original shared variables/expressions.
+  SmallVector<std::pair<LValue, LValue>, 4> SharedAddresses;
+  /// Sizes of the reduction items in chars.
+  SmallVector<llvm::Value *, 4> Sizes;
+  /// Base declarations for the reduction items.
+  SmallVector<const VarDecl *, 4> BaseDecls;
+  /// Emits lvalue for shared expresion.
+  LValue emitSharedLValue(CodeGenFunction &CGF, const Expr *E);
+  /// Emits upper bound for shared expression (if array section).
+  LValue emitSharedLValueUB(CodeGenFunction &CGF, const Expr *E);
+  /// Performs aggregate initialization.
+  /// \param N Number of reduction item in the common list.
+  /// \param PrivateAddr Address of the corresponding private item.
+  /// \param SharedLVal Addreiss of the original shared variable.
+  void emitAggregateInitialization(CodeGenFunction &CGF, unsigned N,
+                                   Address PrivateAddr, LValue SharedLVal);
+
+public:
+  ReductionCodeGen(ArrayRef<const Expr *> Shareds,
+                   ArrayRef<const Expr *> Privates,
+                   ArrayRef<const Expr *> ReductionOps);
+  /// Emits lvalue for a reduction item.
+  /// \param N Number of the reduction item.
+  void emitSharedLValue(CodeGenFunction &CGF, unsigned N);
+  /// Emits the code for the variable-modified type, if required.
+  /// \param N Number of the reduction item.
+  void emitAggregateType(CodeGenFunction &CGF, unsigned N);
+  /// Emits the code for the variable-modified type, if required.
+  /// \param N Number of the reduction item.
+  /// \param Size Size of the type in chars.
+  void emitAggregateType(CodeGenFunction &CGF, unsigned N, llvm::Value *Size);
+  /// Performs initialization of the private copy for the reduction item.
+  /// \param N Number of the reduction item.
+  /// \param PrivateAddr Address of the corresponding private item.
+  /// \param DefaultInit Default initialization sequence that should be
+  /// performed if no reduction specific initialization is found.
+  /// \param SharedLVal Addreiss of the original shared variable.
+  /// \return true, if the initialization sequence was emitted, false otherwise.
+  void
+  emitInitialization(CodeGenFunction &CGF, unsigned N, Address PrivateAddr,
+                     LValue SharedLVal,
+                     llvm::function_ref<bool(CodeGenFunction &)> DefaultInit);
+  /// ReturCns true if the private copy requires cleanups.
+  bool needCleanups(unsigned N);
+  /// Emits cleanup code nfor the reduction item.
+  /// \param N Number of the reduction item.
+  /// \param PrivateAddr Address of the corresponding private item.
+  void emitCleanups(CodeGenFunction &CGF, unsigned N, Address PrivateAddr);
+  /// Adjusts \p PrivatedAddr for using ninstead of the original variable
+  /// address in normal operations.
+  /// \param N Number of the reduction item.
+  /// \param PrivateAddr Address of the corresponding private item.
+  Address adjustPrivateAddress(CodeGenFunction &CGF, unsigned N,
+                               Address PrivateAddr);
+  /// Returns LValue for the reduction item.
+  LValue getSharedLValue(unsigned N) const { return SharedAddresses[N].first; }
+  /// Returns the size of the reduction item in chars, or nullptr, if the size
+  /// is a constant.
+  llvm::Value *getSizeInChars(unsigned N) const { return Sizes[N]; }
+  /// Returns the base declaration of the reduction item.
+  const VarDecl *getBaseDecl(unsigned N) const { return BaseDecls[N]; }
+};
+
 class CGOpenMPRuntime {
 protected:
   CodeGenModule &CGM;
diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index 71797e2..50240d4 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -549,156 +549,6 @@
   EmitBlock(DoneBB, /*IsFinished=*/true);
 }
 
-/// Check if the combiner is a call to UDR combiner and if it is so return the
-/// UDR decl used for reduction.
-static const OMPDeclareReductionDecl *
-getReductionInit(const Expr *ReductionOp) {
-  if (auto *CE = dyn_cast<CallExpr>(ReductionOp))
-    if (auto *OVE = dyn_cast<OpaqueValueExpr>(CE->getCallee()))
-      if (auto *DRE =
-              dyn_cast<DeclRefExpr>(OVE->getSourceExpr()->IgnoreImpCasts()))
-        if (auto *DRD = dyn_cast<OMPDeclareReductionDecl>(DRE->getDecl()))
-          return DRD;
-  return nullptr;
-}
-
-static void emitInitWithReductionInitializer(CodeGenFunction &CGF,
-                                             const OMPDeclareReductionDecl *DRD,
-                                             const Expr *InitOp,
-                                             Address Private, Address Original,
-                                             QualType Ty) {
-  if (DRD->getInitializer()) {
-    std::pair<llvm::Function *, llvm::Function *> Reduction =
-        CGF.CGM.getOpenMPRuntime().getUserDefinedReduction(DRD);
-    auto *CE = cast<CallExpr>(InitOp);
-    auto *OVE = cast<OpaqueValueExpr>(CE->getCallee());
-    const Expr *LHS = CE->getArg(/*Arg=*/0)->IgnoreParenImpCasts();
-    const Expr *RHS = CE->getArg(/*Arg=*/1)->IgnoreParenImpCasts();
-    auto *LHSDRE = cast<DeclRefExpr>(cast<UnaryOperator>(LHS)->getSubExpr());
-    auto *RHSDRE = cast<DeclRefExpr>(cast<UnaryOperator>(RHS)->getSubExpr());
-    CodeGenFunction::OMPPrivateScope PrivateScope(CGF);
-    PrivateScope.addPrivate(cast<VarDecl>(LHSDRE->getDecl()),
-                            [=]() -> Address { return Private; });
-    PrivateScope.addPrivate(cast<VarDecl>(RHSDRE->getDecl()),
-                            [=]() -> Address { return Original; });
-    (void)PrivateScope.Privatize();
-    RValue Func = RValue::get(Reduction.second);
-    CodeGenFunction::OpaqueValueMapping Map(CGF, OVE, Func);
-    CGF.EmitIgnoredExpr(InitOp);
-  } else {
-    llvm::Constant *Init = CGF.CGM.EmitNullConstant(Ty);
-    auto *GV = new llvm::GlobalVariable(
-        CGF.CGM.getModule(), Init->getType(), /*isConstant=*/true,
-        llvm::GlobalValue::PrivateLinkage, Init, ".init");
-    LValue LV = CGF.MakeNaturalAlignAddrLValue(GV, Ty);
-    RValue InitRVal;
-    switch (CGF.getEvaluationKind(Ty)) {
-    case TEK_Scalar:
-      InitRVal = CGF.EmitLoadOfLValue(LV, SourceLocation());
-      break;
-    case TEK_Complex:
-      InitRVal =
-          RValue::getComplex(CGF.EmitLoadOfComplex(LV, SourceLocation()));
-      break;
-    case TEK_Aggregate:
-      InitRVal = RValue::getAggregate(LV.getAddress());
-      break;
-    }
-    OpaqueValueExpr OVE(SourceLocation(), Ty, VK_RValue);
-    CodeGenFunction::OpaqueValueMapping OpaqueMap(CGF, &OVE, InitRVal);
-    CGF.EmitAnyExprToMem(&OVE, Private, Ty.getQualifiers(),
-                         /*IsInitializer=*/false);
-  }
-}
-
-/// \brief Emit initialization of arrays of complex types.
-/// \param DestAddr Address of the array.
-/// \param Type Type of array.
-/// \param Init Initial expression of array.
-/// \param SrcAddr Address of the original array.
-static void EmitOMPAggregateInit(CodeGenFunction &CGF, Address DestAddr,
-                                 QualType Type, const Expr *Init,
-                                 Address SrcAddr = Address::invalid()) {
-  auto *DRD = getReductionInit(Init);
-  // Perform element-by-element initialization.
-  QualType ElementTy;
-
-  // Drill down to the base element type on both arrays.
-  auto ArrayTy = Type->getAsArrayTypeUnsafe();
-  auto NumElements = CGF.emitArrayLength(ArrayTy, ElementTy, DestAddr);
-  DestAddr =
-      CGF.Builder.CreateElementBitCast(DestAddr, DestAddr.getElementType());
-  if (DRD)
-    SrcAddr =
-        CGF.Builder.CreateElementBitCast(SrcAddr, DestAddr.getElementType());
-
-  llvm::Value *SrcBegin = nullptr;
-  if (DRD)
-    SrcBegin = SrcAddr.getPointer();
-  auto DestBegin = DestAddr.getPointer();
-  // Cast from pointer to array type to pointer to single element.
-  auto DestEnd = CGF.Builder.CreateGEP(DestBegin, NumElements);
-  // The basic structure here is a while-do loop.
-  auto BodyBB = CGF.createBasicBlock("omp.arrayinit.body");
-  auto DoneBB = CGF.createBasicBlock("omp.arrayinit.done");
-  auto IsEmpty =
-      CGF.Builder.CreateICmpEQ(DestBegin, DestEnd, "omp.arrayinit.isempty");
-  CGF.Builder.CreateCondBr(IsEmpty, DoneBB, BodyBB);
-
-  // Enter the loop body, making that address the current address.
-  auto EntryBB = CGF.Builder.GetInsertBlock();
-  CGF.EmitBlock(BodyBB);
-
-  CharUnits ElementSize = CGF.getContext().getTypeSizeInChars(ElementTy);
-
-  llvm::PHINode *SrcElementPHI = nullptr;
-  Address SrcElementCurrent = Address::invalid();
-  if (DRD) {
-    SrcElementPHI = CGF.Builder.CreatePHI(SrcBegin->getType(), 2,
-                                          "omp.arraycpy.srcElementPast");
-    SrcElementPHI->addIncoming(SrcBegin, EntryBB);
-    SrcElementCurrent =
-        Address(SrcElementPHI,
-                SrcAddr.getAlignment().alignmentOfArrayElement(ElementSize));
-  }
-  llvm::PHINode *DestElementPHI = CGF.Builder.CreatePHI(
-      DestBegin->getType(), 2, "omp.arraycpy.destElementPast");
-  DestElementPHI->addIncoming(DestBegin, EntryBB);
-  Address DestElementCurrent =
-      Address(DestElementPHI,
-              DestAddr.getAlignment().alignmentOfArrayElement(ElementSize));
-
-  // Emit copy.
-  {
-    CodeGenFunction::RunCleanupsScope InitScope(CGF);
-    if (DRD && (DRD->getInitializer() || !Init)) {
-      emitInitWithReductionInitializer(CGF, DRD, Init, DestElementCurrent,
-                                       SrcElementCurrent, ElementTy);
-    } else
-      CGF.EmitAnyExprToMem(Init, DestElementCurrent, ElementTy.getQualifiers(),
-                           /*IsInitializer=*/false);
-  }
-
-  if (DRD) {
-    // Shift the address forward by one element.
-    auto SrcElementNext = CGF.Builder.CreateConstGEP1_32(
-        SrcElementPHI, /*Idx0=*/1, "omp.arraycpy.dest.element");
-    SrcElementPHI->addIncoming(SrcElementNext, CGF.Builder.GetInsertBlock());
-  }
-
-  // Shift the address forward by one element.
-  auto DestElementNext = CGF.Builder.CreateConstGEP1_32(
-      DestElementPHI, /*Idx0=*/1, "omp.arraycpy.dest.element");
-  // Check whether we've reached the end.
-  auto Done =
-      CGF.Builder.CreateICmpEQ(DestElementNext, DestEnd, "omp.arraycpy.done");
-  CGF.Builder.CreateCondBr(Done, DoneBB, BodyBB);
-  DestElementPHI->addIncoming(DestElementNext, CGF.Builder.GetInsertBlock());
-
-  // Done.
-  CGF.EmitBlock(DoneBB, /*IsFinished=*/true);
-}
-
 void CodeGenFunction::EmitOMPCopy(QualType OriginalType, Address DestAddr,
                                   Address SrcAddr, const VarDecl *DestVD,
                                   const VarDecl *SrcVD, const Expr *Copy) {
@@ -1051,254 +901,107 @@
     EmitBlock(DoneBB, /*IsFinished=*/true);
 }
 
-static Address castToBase(CodeGenFunction &CGF, QualType BaseTy, QualType ElTy,
-                          LValue BaseLV, llvm::Value *Addr) {
-  Address Tmp = Address::invalid();
-  Address TopTmp = Address::invalid();
-  Address MostTopTmp = Address::invalid();
-  BaseTy = BaseTy.getNonReferenceType();
-  while ((BaseTy->isPointerType() || BaseTy->isReferenceType()) &&
-         !CGF.getContext().hasSameType(BaseTy, ElTy)) {
-    Tmp = CGF.CreateMemTemp(BaseTy);
-    if (TopTmp.isValid())
-      CGF.Builder.CreateStore(Tmp.getPointer(), TopTmp);
-    else
-      MostTopTmp = Tmp;
-    TopTmp = Tmp;
-    BaseTy = BaseTy->getPointeeType();
-  }
-  llvm::Type *Ty = BaseLV.getPointer()->getType();
-  if (Tmp.isValid())
-    Ty = Tmp.getElementType();
-  Addr = CGF.Builder.CreatePointerBitCastOrAddrSpaceCast(Addr, Ty);
-  if (Tmp.isValid()) {
-    CGF.Builder.CreateStore(Addr, Tmp);
-    return MostTopTmp;
-  }
-  return Address(Addr, BaseLV.getAlignment());
-}
-
-static LValue loadToBegin(CodeGenFunction &CGF, QualType BaseTy, QualType ElTy,
-                          LValue BaseLV) {
-  BaseTy = BaseTy.getNonReferenceType();
-  while ((BaseTy->isPointerType() || BaseTy->isReferenceType()) &&
-         !CGF.getContext().hasSameType(BaseTy, ElTy)) {
-    if (auto *PtrTy = BaseTy->getAs<PointerType>())
-      BaseLV = CGF.EmitLoadOfPointerLValue(BaseLV.getAddress(), PtrTy);
-    else {
-      BaseLV = CGF.EmitLoadOfReferenceLValue(BaseLV.getAddress(),
-                                             BaseTy->castAs<ReferenceType>());
-    }
-    BaseTy = BaseTy->getPointeeType();
-  }
-  return CGF.MakeAddrLValue(
-      Address(
-          CGF.Builder.CreatePointerBitCastOrAddrSpaceCast(
-              BaseLV.getPointer(), CGF.ConvertTypeForMem(ElTy)->getPointerTo()),
-          BaseLV.getAlignment()),
-      BaseLV.getType(), BaseLV.getBaseInfo());
-}
-
 void CodeGenFunction::EmitOMPReductionClauseInit(
     const OMPExecutableDirective &D,
     CodeGenFunction::OMPPrivateScope &PrivateScope) {
   if (!HaveInsertPoint())
     return;
+  SmallVector<const Expr *, 4> Shareds;
+  SmallVector<const Expr *, 4> Privates;
+  SmallVector<const Expr *, 4> ReductionOps;
+  SmallVector<const Expr *, 4> LHSs;
+  SmallVector<const Expr *, 4> RHSs;
   for (const auto *C : D.getClausesOfKind<OMPReductionClause>()) {
-    auto ILHS = C->lhs_exprs().begin();
-    auto IRHS = C->rhs_exprs().begin();
     auto IPriv = C->privates().begin();
     auto IRed = C->reduction_ops().begin();
-    for (auto IRef : C->varlists()) {
-      auto *LHSVD = cast<VarDecl>(cast<DeclRefExpr>(*ILHS)->getDecl());
-      auto *RHSVD = cast<VarDecl>(cast<DeclRefExpr>(*IRHS)->getDecl());
-      auto *PrivateVD = cast<VarDecl>(cast<DeclRefExpr>(*IPriv)->getDecl());
-      auto *DRD = getReductionInit(*IRed);
-      if (auto *OASE = dyn_cast<OMPArraySectionExpr>(IRef)) {
-        auto *Base = OASE->getBase()->IgnoreParenImpCasts();
-        while (auto *TempOASE = dyn_cast<OMPArraySectionExpr>(Base))
-          Base = TempOASE->getBase()->IgnoreParenImpCasts();
-        while (auto *TempASE = dyn_cast<ArraySubscriptExpr>(Base))
-          Base = TempASE->getBase()->IgnoreParenImpCasts();
-        auto *DE = cast<DeclRefExpr>(Base);
-        auto *OrigVD = cast<VarDecl>(DE->getDecl());
-        auto OASELValueLB = EmitOMPArraySectionExpr(OASE);
-        auto OASELValueUB =
-            EmitOMPArraySectionExpr(OASE, /*IsLowerBound=*/false);
-        auto OriginalBaseLValue = EmitLValue(DE);
-        LValue BaseLValue =
-            loadToBegin(*this, OrigVD->getType(), OASELValueLB.getType(),
-                        OriginalBaseLValue);
-        // Store the address of the original variable associated with the LHS
-        // implicit variable.
-        PrivateScope.addPrivate(LHSVD, [OASELValueLB]() -> Address {
-          return OASELValueLB.getAddress();
-        });
-        // Emit reduction copy.
-        bool IsRegistered = PrivateScope.addPrivate(
-            OrigVD, [this, OrigVD, PrivateVD, BaseLValue, OASELValueLB,
-                     OASELValueUB, OriginalBaseLValue, DRD, IRed]() -> Address {
-              // Emit VarDecl with copy init for arrays.
-              // Get the address of the original variable captured in current
-              // captured region.
-              auto *Size = Builder.CreatePtrDiff(OASELValueUB.getPointer(),
-                                                 OASELValueLB.getPointer());
-              Size = Builder.CreateNUWAdd(
-                  Size, llvm::ConstantInt::get(Size->getType(), /*V=*/1));
-              CodeGenFunction::OpaqueValueMapping OpaqueMap(
-                  *this, cast<OpaqueValueExpr>(
-                             getContext()
-                                 .getAsVariableArrayType(PrivateVD->getType())
-                                 ->getSizeExpr()),
-                  RValue::get(Size));
-              EmitVariablyModifiedType(PrivateVD->getType());
-              auto Emission = EmitAutoVarAlloca(*PrivateVD);
-              auto Addr = Emission.getAllocatedAddress();
-              auto *Init = PrivateVD->getInit();
-              EmitOMPAggregateInit(*this, Addr, PrivateVD->getType(),
-                                   DRD ? *IRed : Init,
-                                   OASELValueLB.getAddress());
-              EmitAutoVarCleanups(Emission);
-              // Emit private VarDecl with reduction init.
-              auto *Offset = Builder.CreatePtrDiff(BaseLValue.getPointer(),
-                                                   OASELValueLB.getPointer());
-              auto *Ptr = Builder.CreateGEP(Addr.getPointer(), Offset);
-              return castToBase(*this, OrigVD->getType(),
-                                OASELValueLB.getType(), OriginalBaseLValue,
-                                Ptr);
-            });
-        assert(IsRegistered && "private var already registered as private");
-        // Silence the warning about unused variable.
-        (void)IsRegistered;
-        PrivateScope.addPrivate(RHSVD, [this, PrivateVD]() -> Address {
-          return GetAddrOfLocalVar(PrivateVD);
-        });
-      } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(IRef)) {
-        auto *Base = ASE->getBase()->IgnoreParenImpCasts();
-        while (auto *TempASE = dyn_cast<ArraySubscriptExpr>(Base))
-          Base = TempASE->getBase()->IgnoreParenImpCasts();
-        auto *DE = cast<DeclRefExpr>(Base);
-        auto *OrigVD = cast<VarDecl>(DE->getDecl());
-        auto ASELValue = EmitLValue(ASE);
-        auto OriginalBaseLValue = EmitLValue(DE);
-        LValue BaseLValue = loadToBegin(
-            *this, OrigVD->getType(), ASELValue.getType(), OriginalBaseLValue);
-        // Store the address of the original variable associated with the LHS
-        // implicit variable.
-        PrivateScope.addPrivate(
-            LHSVD, [ASELValue]() -> Address { return ASELValue.getAddress(); });
-        // Emit reduction copy.
-        bool IsRegistered = PrivateScope.addPrivate(
-            OrigVD, [this, OrigVD, PrivateVD, BaseLValue, ASELValue,
-                     OriginalBaseLValue, DRD, IRed]() -> Address {
-              // Emit private VarDecl with reduction init.
-              AutoVarEmission Emission = EmitAutoVarAlloca(*PrivateVD);
-              auto Addr = Emission.getAllocatedAddress();
-              if (DRD && (DRD->getInitializer() || !PrivateVD->hasInit())) {
-                emitInitWithReductionInitializer(*this, DRD, *IRed, Addr,
-                                                 ASELValue.getAddress(),
-                                                 ASELValue.getType());
-              } else
-                EmitAutoVarInit(Emission);
-              EmitAutoVarCleanups(Emission);
-              auto *Offset = Builder.CreatePtrDiff(BaseLValue.getPointer(),
-                                                   ASELValue.getPointer());
-              auto *Ptr = Builder.CreateGEP(Addr.getPointer(), Offset);
-              return castToBase(*this, OrigVD->getType(), ASELValue.getType(),
-                                OriginalBaseLValue, Ptr);
-            });
-        assert(IsRegistered && "private var already registered as private");
-        // Silence the warning about unused variable.
-        (void)IsRegistered;
-        PrivateScope.addPrivate(RHSVD, [this, PrivateVD, RHSVD]() -> Address {
-          return Builder.CreateElementBitCast(
-              GetAddrOfLocalVar(PrivateVD), ConvertTypeForMem(RHSVD->getType()),
-              "rhs.begin");
-        });
-      } else {
-        auto *OrigVD = cast<VarDecl>(cast<DeclRefExpr>(IRef)->getDecl());
-        QualType Type = PrivateVD->getType();
-        if (getContext().getAsArrayType(Type)) {
-          // Store the address of the original variable associated with the LHS
-          // implicit variable.
-          DeclRefExpr DRE(const_cast<VarDecl *>(OrigVD),
-                          CapturedStmtInfo->lookup(OrigVD) != nullptr,
-                          IRef->getType(), VK_LValue, IRef->getExprLoc());
-          Address OriginalAddr = EmitLValue(&DRE).getAddress();
-          PrivateScope.addPrivate(LHSVD, [this, &OriginalAddr,
-                                          LHSVD]() -> Address {
-            OriginalAddr = Builder.CreateElementBitCast(
-                OriginalAddr, ConvertTypeForMem(LHSVD->getType()), "lhs.begin");
-            return OriginalAddr;
-          });
-          bool IsRegistered = PrivateScope.addPrivate(OrigVD, [&]() -> Address {
-            if (Type->isVariablyModifiedType()) {
-              CodeGenFunction::OpaqueValueMapping OpaqueMap(
-                  *this, cast<OpaqueValueExpr>(
-                             getContext()
-                                 .getAsVariableArrayType(PrivateVD->getType())
-                                 ->getSizeExpr()),
-                  RValue::get(
-                      getTypeSize(OrigVD->getType().getNonReferenceType())));
-              EmitVariablyModifiedType(Type);
-            }
-            auto Emission = EmitAutoVarAlloca(*PrivateVD);
-            auto Addr = Emission.getAllocatedAddress();
-            auto *Init = PrivateVD->getInit();
-            EmitOMPAggregateInit(*this, Addr, PrivateVD->getType(),
-                                 DRD ? *IRed : Init, OriginalAddr);
-            EmitAutoVarCleanups(Emission);
-            return Emission.getAllocatedAddress();
-          });
-          assert(IsRegistered && "private var already registered as private");
-          // Silence the warning about unused variable.
-          (void)IsRegistered;
-          PrivateScope.addPrivate(RHSVD, [this, PrivateVD, RHSVD]() -> Address {
-            return Builder.CreateElementBitCast(
-                GetAddrOfLocalVar(PrivateVD),
-                ConvertTypeForMem(RHSVD->getType()), "rhs.begin");
-          });
-        } else {
-          // Store the address of the original variable associated with the LHS
-          // implicit variable.
-          Address OriginalAddr = Address::invalid();
-          PrivateScope.addPrivate(LHSVD, [this, OrigVD, IRef,
-                                          &OriginalAddr]() -> Address {
-            DeclRefExpr DRE(const_cast<VarDecl *>(OrigVD),
-                            CapturedStmtInfo->lookup(OrigVD) != nullptr,
-                            IRef->getType(), VK_LValue, IRef->getExprLoc());
-            OriginalAddr = EmitLValue(&DRE).getAddress();
-            return OriginalAddr;
-          });
-          // Emit reduction copy.
-          bool IsRegistered = PrivateScope.addPrivate(
-              OrigVD, [this, PrivateVD, OriginalAddr, DRD, IRed]() -> Address {
-                // Emit private VarDecl with reduction init.
-                AutoVarEmission Emission = EmitAutoVarAlloca(*PrivateVD);
-                auto Addr = Emission.getAllocatedAddress();
-                if (DRD && (DRD->getInitializer() || !PrivateVD->hasInit())) {
-                  emitInitWithReductionInitializer(*this, DRD, *IRed, Addr,
-                                                   OriginalAddr,
-                                                   PrivateVD->getType());
-                } else
-                  EmitAutoVarInit(Emission);
-                EmitAutoVarCleanups(Emission);
-                return Addr;
-              });
-          assert(IsRegistered && "private var already registered as private");
-          // Silence the warning about unused variable.
-          (void)IsRegistered;
-          PrivateScope.addPrivate(RHSVD, [this, PrivateVD]() -> Address {
-            return GetAddrOfLocalVar(PrivateVD);
-          });
-        }
-      }
-      ++ILHS;
-      ++IRHS;
-      ++IPriv;
-      ++IRed;
+    auto ILHS = C->lhs_exprs().begin();
+    auto IRHS = C->rhs_exprs().begin();
+    for (const auto *Ref : C->varlists()) {
+      Shareds.emplace_back(Ref);
+      Privates.emplace_back(*IPriv);
+      ReductionOps.emplace_back(*IRed);
+      LHSs.emplace_back(*ILHS);
+      RHSs.emplace_back(*IRHS);
+      std::advance(IPriv, 1);
+      std::advance(IRed, 1);
+      std::advance(ILHS, 1);
+      std::advance(IRHS, 1);
     }
   }
+  ReductionCodeGen RedCG(Shareds, Privates, ReductionOps);
+  unsigned Count = 0;
+  auto ILHS = LHSs.begin();
+  auto IRHS = RHSs.begin();
+  auto IPriv = Privates.begin();
+  for (const auto *IRef : Shareds) {
+    auto *PrivateVD = cast<VarDecl>(cast<DeclRefExpr>(*IPriv)->getDecl());
+    // Emit private VarDecl with reduction init.
+    RedCG.emitSharedLValue(*this, Count);
+    RedCG.emitAggregateType(*this, Count);
+    auto Emission = EmitAutoVarAlloca(*PrivateVD);
+    RedCG.emitInitialization(*this, Count, Emission.getAllocatedAddress(),
+                             RedCG.getSharedLValue(Count),
+                             [&Emission](CodeGenFunction &CGF) {
+                               CGF.EmitAutoVarInit(Emission);
+                               return true;
+                             });
+    EmitAutoVarCleanups(Emission);
+    Address BaseAddr = RedCG.adjustPrivateAddress(
+        *this, Count, Emission.getAllocatedAddress());
+    bool IsRegistered = PrivateScope.addPrivate(
+        RedCG.getBaseDecl(Count), [BaseAddr]() -> Address { return BaseAddr; });
+    assert(IsRegistered && "private var already registered as private");
+    // Silence the warning about unused variable.
+    (void)IsRegistered;
+
+    auto *LHSVD = cast<VarDecl>(cast<DeclRefExpr>(*ILHS)->getDecl());
+    auto *RHSVD = cast<VarDecl>(cast<DeclRefExpr>(*IRHS)->getDecl());
+    if (auto *OASE = dyn_cast<OMPArraySectionExpr>(IRef)) {
+      // Store the address of the original variable associated with the LHS
+      // implicit variable.
+      PrivateScope.addPrivate(LHSVD, [&RedCG, Count]() -> Address {
+        return RedCG.getSharedLValue(Count).getAddress();
+      });
+      PrivateScope.addPrivate(RHSVD, [this, PrivateVD]() -> Address {
+        return GetAddrOfLocalVar(PrivateVD);
+      });
+    } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(IRef)) {
+      // Store the address of the original variable associated with the LHS
+      // implicit variable.
+      PrivateScope.addPrivate(LHSVD, [&RedCG, Count]() -> Address {
+        return RedCG.getSharedLValue(Count).getAddress();
+      });
+      PrivateScope.addPrivate(RHSVD, [this, PrivateVD, RHSVD]() -> Address {
+        return Builder.CreateElementBitCast(GetAddrOfLocalVar(PrivateVD),
+                                            ConvertTypeForMem(RHSVD->getType()),
+                                            "rhs.begin");
+      });
+    } else {
+      QualType Type = PrivateVD->getType();
+      bool IsArray = getContext().getAsArrayType(Type) != nullptr;
+      Address OriginalAddr = RedCG.getSharedLValue(Count).getAddress();
+      // Store the address of the original variable associated with the LHS
+      // implicit variable.
+      if (IsArray) {
+        OriginalAddr = Builder.CreateElementBitCast(
+            OriginalAddr, ConvertTypeForMem(LHSVD->getType()), "lhs.begin");
+      }
+      PrivateScope.addPrivate(
+          LHSVD, [OriginalAddr]() -> Address { return OriginalAddr; });
+      PrivateScope.addPrivate(
+          RHSVD, [this, PrivateVD, RHSVD, IsArray]() -> Address {
+            return IsArray
+                       ? Builder.CreateElementBitCast(
+                             GetAddrOfLocalVar(PrivateVD),
+                             ConvertTypeForMem(RHSVD->getType()), "rhs.begin")
+                       : GetAddrOfLocalVar(PrivateVD);
+          });
+    }
+    ++ILHS;
+    ++IRHS;
+    ++IPriv;
+    ++Count;
+  }
 }
 
 void CodeGenFunction::EmitOMPReductionClauseFinal(
diff --git a/clang/test/OpenMP/for_reduction_codegen.cpp b/clang/test/OpenMP/for_reduction_codegen.cpp
index 274546b..01a179c 100644
--- a/clang/test/OpenMP/for_reduction_codegen.cpp
+++ b/clang/test/OpenMP/for_reduction_codegen.cpp
@@ -718,7 +718,6 @@
 // CHECK: br i1 [[DONE]],
 
 // Check initialization of private copy.
-// CHECK: [[LHS_BEGIN:%.+]] = bitcast [10 x [4 x [[S_FLOAT_TY]]]]* %{{.+}} to [[S_FLOAT_TY]]*
 // CHECK: [[BEGIN:%.+]] = getelementptr inbounds [10 x [4 x [[S_FLOAT_TY]]]], [10 x [4 x [[S_FLOAT_TY]]]]* [[ARRS_PRIV]], i32 0, i32 0, i32 0
 // CHECK: [[END:%.+]] = getelementptr [[S_FLOAT_TY]], [[S_FLOAT_TY]]* [[BEGIN]], i64 40
 // CHECK: [[ISEMPTY:%.+]] = icmp eq [[S_FLOAT_TY]]* [[BEGIN]], [[END]]
@@ -727,6 +726,7 @@
 // CHECK: call void @_ZN1SIfEC1Ev([[S_FLOAT_TY]]* %
 // CHECK: [[DONE:%.+]] = icmp eq [[S_FLOAT_TY]]* %{{.+}}, [[END]]
 // CHECK: br i1 [[DONE]],
+// CHECK: [[LHS_BEGIN:%.+]] = bitcast [10 x [4 x [[S_FLOAT_TY]]]]* %{{.+}} to [[S_FLOAT_TY]]*
 // CHECK: [[ARRS_PRIV_BEGIN:%.+]] = bitcast [10 x [4 x [[S_FLOAT_TY]]]]* [[ARRS_PRIV]] to [[S_FLOAT_TY]]*
 
 // CHECK: [[GTID_REF:%.+]] = load i{{[0-9]+}}*, i{{[0-9]+}}** [[GTID_ADDR_ADDR]]
@@ -903,8 +903,6 @@
 // CHECK: getelementptr inbounds [[S_FLOAT_TY]]*, [[S_FLOAT_TY]]** %{{.+}}, i64 4
 // CHECK: load [[S_FLOAT_TY]]*, [[S_FLOAT_TY]]** %
 // CHECK: getelementptr inbounds [[S_FLOAT_TY]], [[S_FLOAT_TY]]* %{{.+}}, i64 6
-// CHECK: [[LD:%.+]] = load [[S_FLOAT_TY]]**, [[S_FLOAT_TY]]*** [[VAR2_ORIG]],
-// CHECK: [[ORIG_START:%.+]] = load [[S_FLOAT_TY]]*, [[S_FLOAT_TY]]** [[LD]],
 // CHECK: [[LAST:%.+]] = ptrtoint [[S_FLOAT_TY]]* %{{.+}} to i64
 // CHECK: [[FIRST:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[BYTE_DIF:%.+]] = sub i64 [[LAST]], [[FIRST]]
@@ -912,6 +910,8 @@
 // CHECK: [[SIZE:%.+]] = add nuw i64 [[DIF]], 1
 // CHECK: call i8* @llvm.stacksave()
 // CHECK: [[VAR2_PRIV:%.+]] = alloca [[S_FLOAT_TY]], i64 [[SIZE]],
+// CHECK: [[LD:%.+]] = load [[S_FLOAT_TY]]**, [[S_FLOAT_TY]]*** [[VAR2_ORIG]],
+// CHECK: [[ORIG_START:%.+]] = load [[S_FLOAT_TY]]*, [[S_FLOAT_TY]]** [[LD]],
 // CHECK: [[START:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[ORIG_START]] to i64
 // CHECK: [[LOW_BOUND:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[OFFSET_BYTES:%.+]] = sub i64 [[START]], [[LOW_BOUND]]
@@ -933,7 +933,6 @@
 
 // CHECK: [[LOW:%.+]] = getelementptr inbounds [2 x [[S_FLOAT_TY]]], [2 x [[S_FLOAT_TY]]]* [[VVAR2_ORIG]], i64 0, i64 0
 // CHECK: getelementptr inbounds [2 x [[S_FLOAT_TY]]], [2 x [[S_FLOAT_TY]]]* [[VVAR2_ORIG]], i64 0, i64 4
-// CHECK: [[ORIG_START:%.+]] = bitcast [2 x [[S_FLOAT_TY]]]* [[VVAR2_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: [[LAST:%.+]] = ptrtoint [[S_FLOAT_TY]]* %{{.+}} to i64
 // CHECK: [[FIRST:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[BYTE_DIF:%.+]] = sub i64 [[LAST]], [[FIRST]]
@@ -941,6 +940,7 @@
 // CHECK: [[SIZE:%.+]] = add nuw i64 [[DIF]], 1
 // CHECK: call i8* @llvm.stacksave()
 // CHECK: [[VVAR2_PRIV:%.+]] = alloca [[S_FLOAT_TY]], i64 [[SIZE]],
+// CHECK: [[ORIG_START:%.+]] = bitcast [2 x [[S_FLOAT_TY]]]* [[VVAR2_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: [[START:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[ORIG_START]] to i64
 // CHECK: [[LOW_BOUND:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[OFFSET_BYTES:%.+]] = sub i64 [[START]], [[LOW_BOUND]]
@@ -964,8 +964,6 @@
 // CHECK: [[LOW:%.+]] = getelementptr inbounds [2 x [[S_FLOAT_TY]]], [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]], i64 0, i64 1
 // CHECK: [[VAR3_ORIG:%.+]] = load [2 x [[S_FLOAT_TY]]]*, [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR]],
 // CHECK: getelementptr inbounds [2 x [[S_FLOAT_TY]]], [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]], i64 0, i64 2
-// CHECK: [[VAR3_ORIG:%.+]] = load [2 x [[S_FLOAT_TY]]]*, [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR]],
-// CHECK: [[ORIG_START:%.+]] = bitcast [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: [[LAST:%.+]] = ptrtoint [[S_FLOAT_TY]]* %{{.+}} to i64
 // CHECK: [[FIRST:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[BYTE_DIF:%.+]] = sub i64 [[LAST]], [[FIRST]]
@@ -973,6 +971,8 @@
 // CHECK: [[SIZE:%.+]] = add nuw i64 [[DIF]], 1
 // CHECK: call i8* @llvm.stacksave()
 // CHECK: [[VAR3_PRIV:%.+]] = alloca [[S_FLOAT_TY]], i64 [[SIZE]],
+// CHECK: [[VAR3_ORIG:%.+]] = load [2 x [[S_FLOAT_TY]]]*, [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR]],
+// CHECK: [[ORIG_START:%.+]] = bitcast [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: [[START:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[ORIG_START]] to i64
 // CHECK: [[LOW_BOUND:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[OFFSET_BYTES:%.+]] = sub i64 [[START]], [[LOW_BOUND]]
@@ -997,11 +997,11 @@
 // CHECK: [[VAR3_ORIG:%.+]] = load [2 x [[S_FLOAT_TY]]]*, [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR]],
 // CHECK: store [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]], [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR:%.+]],
 // CHECK: [[VAR3_ORIG:%.+]] = load [2 x [[S_FLOAT_TY]]]*, [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR]],
-// CHECK: bitcast [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: getelementptr inbounds [2 x [[S_FLOAT_TY]]], [2 x [[S_FLOAT_TY]]]* [[VAR3_PRIV]], i32 0, i32 0
 // CHECK: getelementptr [[S_FLOAT_TY]], [[S_FLOAT_TY]]* %{{.+}}, i64 2
 
 // CHECK: store [2 x [[S_FLOAT_TY]]]* [[VAR3_PRIV]], [2 x [[S_FLOAT_TY]]]** %
+// CHECK: bitcast [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]] to [[S_FLOAT_TY]]*
 
 // CHECK: ret void
 
diff --git a/clang/test/OpenMP/for_reduction_codegen_UDR.cpp b/clang/test/OpenMP/for_reduction_codegen_UDR.cpp
index 699e06d..4f14b9d 100644
--- a/clang/test/OpenMP/for_reduction_codegen_UDR.cpp
+++ b/clang/test/OpenMP/for_reduction_codegen_UDR.cpp
@@ -522,8 +522,8 @@
 // CHECK: br i1 [[DONE]],
 
 // Check initialization of private copy.
-// CHECK: [[LHS_BEGIN:%.+]] = bitcast [10 x [4 x [[S_FLOAT_TY]]]]* %{{.+}} to [[S_FLOAT_TY]]*
 // CHECK: [[BEGIN:%.+]] = getelementptr inbounds [10 x [4 x [[S_FLOAT_TY]]]], [10 x [4 x [[S_FLOAT_TY]]]]* [[ARRS_PRIV]], i32 0, i32 0, i32 0
+// CHECK: [[LHS_BEGIN:%.+]] = bitcast [10 x [4 x [[S_FLOAT_TY]]]]* %{{.+}} to [[S_FLOAT_TY]]*
 // CHECK: [[END:%.+]] = getelementptr [[S_FLOAT_TY]], [[S_FLOAT_TY]]* [[BEGIN]], i64 40
 // CHECK: [[ISEMPTY:%.+]] = icmp eq [[S_FLOAT_TY]]* [[BEGIN]], [[END]]
 // CHECK: br i1 [[ISEMPTY]],
@@ -531,6 +531,7 @@
 // CHECK: call void @_Z4initR6BaseS1RKS_(%
 // CHECK: [[DONE:%.+]] = icmp eq [[S_FLOAT_TY]]* %{{.+}}, [[END]]
 // CHECK: br i1 [[DONE]],
+// CHECK: [[LHS_BEGIN:%.+]] = bitcast [10 x [4 x [[S_FLOAT_TY]]]]* %{{.+}} to [[S_FLOAT_TY]]*
 // CHECK: [[ARRS_PRIV_BEGIN:%.+]] = bitcast [10 x [4 x [[S_FLOAT_TY]]]]* [[ARRS_PRIV]] to [[S_FLOAT_TY]]*
 
 // CHECK: [[GTID_REF:%.+]] = load i{{[0-9]+}}*, i{{[0-9]+}}** [[GTID_ADDR_ADDR]]
@@ -703,8 +704,6 @@
 // CHECK: getelementptr inbounds [[S_FLOAT_TY]]*, [[S_FLOAT_TY]]** %{{.+}}, i64 4
 // CHECK: load [[S_FLOAT_TY]]*, [[S_FLOAT_TY]]** %
 // CHECK: getelementptr inbounds [[S_FLOAT_TY]], [[S_FLOAT_TY]]* %{{.+}}, i64 6
-// CHECK: [[LD:%.+]] = load [[S_FLOAT_TY]]**, [[S_FLOAT_TY]]*** [[VAR2_ORIG]],
-// CHECK: [[ORIG_START:%.+]] = load [[S_FLOAT_TY]]*, [[S_FLOAT_TY]]** [[LD]],
 // CHECK: [[LAST:%.+]] = ptrtoint [[S_FLOAT_TY]]* %{{.+}} to i64
 // CHECK: [[FIRST:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[BYTE_DIF:%.+]] = sub i64 [[LAST]], [[FIRST]]
@@ -712,6 +711,8 @@
 // CHECK: [[SIZE:%.+]] = add nuw i64 [[DIF]], 1
 // CHECK: call i8* @llvm.stacksave()
 // CHECK: [[VAR2_PRIV:%.+]] = alloca [[S_FLOAT_TY]], i64 [[SIZE]],
+// CHECK: [[LD:%.+]] = load [[S_FLOAT_TY]]**, [[S_FLOAT_TY]]*** [[VAR2_ORIG]],
+// CHECK: [[ORIG_START:%.+]] = load [[S_FLOAT_TY]]*, [[S_FLOAT_TY]]** [[LD]],
 // CHECK: [[START:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[ORIG_START]] to i64
 // CHECK: [[LOW_BOUND:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[OFFSET_BYTES:%.+]] = sub i64 [[START]], [[LOW_BOUND]]
@@ -733,7 +734,6 @@
 
 // CHECK: [[LOW:%.+]] = getelementptr inbounds [2 x [[S_FLOAT_TY]]], [2 x [[S_FLOAT_TY]]]* [[VVAR2_ORIG]], i64 0, i64 0
 // CHECK: getelementptr inbounds [2 x [[S_FLOAT_TY]]], [2 x [[S_FLOAT_TY]]]* [[VVAR2_ORIG]], i64 0, i64 4
-// CHECK: [[ORIG_START:%.+]] = bitcast [2 x [[S_FLOAT_TY]]]* [[VVAR2_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: [[LAST:%.+]] = ptrtoint [[S_FLOAT_TY]]* %{{.+}} to i64
 // CHECK: [[FIRST:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[BYTE_DIF:%.+]] = sub i64 [[LAST]], [[FIRST]]
@@ -741,6 +741,7 @@
 // CHECK: [[SIZE:%.+]] = add nuw i64 [[DIF]], 1
 // CHECK: call i8* @llvm.stacksave()
 // CHECK: [[VVAR2_PRIV:%.+]] = alloca [[S_FLOAT_TY]], i64 [[SIZE]],
+// CHECK: [[ORIG_START:%.+]] = bitcast [2 x [[S_FLOAT_TY]]]* [[VVAR2_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: [[START:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[ORIG_START]] to i64
 // CHECK: [[LOW_BOUND:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[OFFSET_BYTES:%.+]] = sub i64 [[START]], [[LOW_BOUND]]
@@ -764,8 +765,6 @@
 // CHECK: [[LOW:%.+]] = getelementptr inbounds [2 x [[S_FLOAT_TY]]], [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]], i64 0, i64 1
 // CHECK: [[VAR3_ORIG:%.+]] = load [2 x [[S_FLOAT_TY]]]*, [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR]],
 // CHECK: getelementptr inbounds [2 x [[S_FLOAT_TY]]], [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]], i64 0, i64 2
-// CHECK: [[VAR3_ORIG:%.+]] = load [2 x [[S_FLOAT_TY]]]*, [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR]],
-// CHECK: [[ORIG_START:%.+]] = bitcast [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: [[LAST:%.+]] = ptrtoint [[S_FLOAT_TY]]* %{{.+}} to i64
 // CHECK: [[FIRST:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[BYTE_DIF:%.+]] = sub i64 [[LAST]], [[FIRST]]
@@ -773,6 +772,8 @@
 // CHECK: [[SIZE:%.+]] = add nuw i64 [[DIF]], 1
 // CHECK: call i8* @llvm.stacksave()
 // CHECK: [[VAR3_PRIV:%.+]] = alloca [[S_FLOAT_TY]], i64 [[SIZE]],
+// CHECK: [[VAR3_ORIG:%.+]] = load [2 x [[S_FLOAT_TY]]]*, [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR]],
+// CHECK: [[ORIG_START:%.+]] = bitcast [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: [[START:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[ORIG_START]] to i64
 // CHECK: [[LOW_BOUND:%.+]] = ptrtoint [[S_FLOAT_TY]]* [[LOW]] to i64
 // CHECK: [[OFFSET_BYTES:%.+]] = sub i64 [[START]], [[LOW_BOUND]]
@@ -797,8 +798,8 @@
 // CHECK: [[VAR3_ORIG:%.+]] = load [2 x [[S_FLOAT_TY]]]*, [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR]],
 // CHECK: store [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]], [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR:%.+]],
 // CHECK: [[VAR3_ORIG:%.+]] = load [2 x [[S_FLOAT_TY]]]*, [2 x [[S_FLOAT_TY]]]** [[VAR3_ORIG_ADDR]],
-// CHECK: bitcast [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: getelementptr inbounds [2 x [[S_FLOAT_TY]]], [2 x [[S_FLOAT_TY]]]* [[VAR3_PRIV]], i32 0, i32 0
+// CHECK: bitcast [2 x [[S_FLOAT_TY]]]* [[VAR3_ORIG]] to [[S_FLOAT_TY]]*
 // CHECK: getelementptr [[S_FLOAT_TY]], [[S_FLOAT_TY]]* %{{.+}}, i64 2
 
 // CHECK: store [2 x [[S_FLOAT_TY]]]* [[VAR3_PRIV]], [2 x [[S_FLOAT_TY]]]** %