[OpenMP] Parallel reduction on the NVPTX device.

[arpith-jacob]

Summary

This patch implements codegen for the reduction clause on
any parallel construct for elementary data types. An efficient
implementation requires hierarchical reduction within a
warp and a threadblock. It is complicated by the fact that
variables declared in the stack of a CUDA thread cannot be
shared with other threads.

The patch creates a struct to hold reduction variables and
a number of helper functions. The OpenMP runtime on the GPU
implements reduction algorithms that uses these helper
functions to perform reductions within a team. Variables are
shared between CUDA threads using shuffle intrinsics.

An implementation of reductions on the NVPTX device is
substantially different to that of CPUs. However, this patch
is written so that there are minimal changes to the rest of
OpenMP codegen.

The implemented design allows the compiler and runtime to be
decoupled, i.e., the runtime does not need to know of the
reduction operation(s), the type of the reduction variable(s),
or the number of reductions. The design also allows reuse of
host codegen, with appropriate specialization for the NVPTX
device.

While the patch does introduce a number of abstractions, the
expected use case calls for inlining of the GPU OpenMP runtime.
After inlining and optimizations in LLVM, these abstractions
are unwound and performance of OpenMP reductions is comparable
to CUDA-canonical code.

Patch by Tian Jin in collaboration with Arpith Jacob

[ABataev]

lib/CodeGen/CGOpenMPRuntime.h

956–962 ↗

(On Diff #87799)

Number of parameters is getting too big, maybe it is better to aggregate them into a struct/class?

lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp

118–133 ↗

(On Diff #87799)

It's better to use /// style of comments here

653–675 ↗

(On Diff #87799)

Use // instead of ///

963–965 ↗

(On Diff #87799)

Comments here?

969–974 ↗

(On Diff #87799)

Use ///

1272 ↗

(On Diff #87799)

/// style here

1488 ↗

(On Diff #87799)

/// here

lib/CodeGen/CGOpenMPRuntimeNVPTX.h

245 ↗

(On Diff #87799)

Bo \brief

263 ↗

(On Diff #87799)

No \brief

[arpith-jacob]

lib/CodeGen/CGOpenMPRuntime.h

956–962 ↗

(On Diff #87799)

Thanks Alexey for your comments. I can place 'WithNoWait, SimpleReduction, ReductionKind' in a struct.

Can you explain what 'SimpleReduction' stands for? It isn't create to me when the reduction is simple...

Thanks.

[arpith-jacob]

Updated patch to address Alexey's comments. Condensed parameters in emitReduction() to a struct Options.

[arpith-jacob]

Minor fixup of comment style on emitInterWarpCopyFunction().

[ABataev]

LG

cfe/trunk/lib/CodeGen/CGOpenMPRuntime.h

public:
   /// is a directive itself, for combined - its innermost directive).
   /// \param CodeGen Code generation sequence for the \a D directive.
   /// \param HasCancel true if region has inner cancel directive, false
   /// otherwise.
   virtual void emitInlinedDirective(CodeGenFunction &CGF,
                                     OpenMPDirectiveKind InnermostKind,
                                     const RegionCodeGenTy &CodeGen,
                                     bool HasCancel = false);
+
+  /// Emits reduction function.
+  /// \param ArgsType Array type containing pointers to reduction variables.
+  /// \param Privates List of private copies for original reduction arguments.
+  /// \param LHSExprs List of LHS in \a ReductionOps reduction operations.
+  /// \param RHSExprs List of RHS in \a ReductionOps reduction operations.
+  /// \param ReductionOps List of reduction operations in form 'LHS binop RHS'
+  /// or 'operator binop(LHS, RHS)'.
+  llvm::Value *emitReductionFunction(CodeGenModule &CGM, llvm::Type *ArgsType,
+                                     ArrayRef<const Expr *> Privates,
+                                     ArrayRef<const Expr *> LHSExprs,
+                                     ArrayRef<const Expr *> RHSExprs,
+                                     ArrayRef<const Expr *> ReductionOps);
+
+  /// Emits single reduction combiner
+  void emitSingleReductionCombiner(CodeGenFunction &CGF,
+                                   const Expr *ReductionOp,
+                                   const Expr *PrivateRef,
+                                   const DeclRefExpr *LHS,
+                                   const DeclRefExpr *RHS);
+
+  struct ReductionOptionsTy {
+    bool WithNowait;
+    bool SimpleReduction;
+    OpenMPDirectiveKind ReductionKind;
+  };
   /// \brief Emit a code for reduction clause. Next code should be emitted for
   /// reduction:
   /// \code
   ///
   /// static kmp_critical_name lock = { 0 };
   ///
   /// void reduce_func(void *lhs[<n>], void *rhs[<n>]) {
   ///  ...
public:
   /// }
   /// \endcode
   ///
   /// \param Privates List of private copies for original reduction arguments.
   /// \param LHSExprs List of LHS in \a ReductionOps reduction operations.
   /// \param RHSExprs List of RHS in \a ReductionOps reduction operations.
   /// \param ReductionOps List of reduction operations in form 'LHS binop RHS'
   /// or 'operator binop(LHS, RHS)'.
-  /// \param WithNowait true if parent directive has also nowait clause, false
-  /// otherwise.
+  /// \param Options List of options for reduction codegen:
+  ///     WithNowait true if parent directive has also nowait clause, false
+  ///     otherwise.
+  ///     SimpleReduction Emit reduction operation only. Used for omp simd
+  ///     directive on the host.
+  ///     ReductionKind The kind of reduction to perform.
   virtual void emitReduction(CodeGenFunction &CGF, SourceLocation Loc,
                              ArrayRef<const Expr *> Privates,
                              ArrayRef<const Expr *> LHSExprs,
                              ArrayRef<const Expr *> RHSExprs,
                              ArrayRef<const Expr *> ReductionOps,
-                             bool WithNowait, bool SimpleReduction);
+                             ReductionOptionsTy Options);
 
   /// \brief Emit code for 'taskwait' directive.
   virtual void emitTaskwaitCall(CodeGenFunction &CGF, SourceLocation Loc);
 
   /// \brief Emit code for 'cancellation point' construct.
   /// \param CancelRegion Region kind for which the cancellation point must be
   /// emitted.
   ///

cfe/trunk/lib/CodeGen/CGOpenMPRuntime.cpp

if (auto *OVE = dyn_cast<OpaqueValueExpr>(CE->getCallee()))
           RValue Func = RValue::get(Reduction.first);
           CodeGenFunction::OpaqueValueMapping Map(CGF, OVE, Func);
           CGF.EmitIgnoredExpr(ReductionOp);
           return;
         }
   CGF.EmitIgnoredExpr(ReductionOp);
 }
 
-static llvm::Value *emitReductionFunction(CodeGenModule &CGM,
-                                          llvm::Type *ArgsType,
-                                          ArrayRef<const Expr *> Privates,
-                                          ArrayRef<const Expr *> LHSExprs,
-                                          ArrayRef<const Expr *> RHSExprs,
-                                          ArrayRef<const Expr *> ReductionOps) {
+llvm::Value *CGOpenMPRuntime::emitReductionFunction(
+    CodeGenModule &CGM, llvm::Type *ArgsType, ArrayRef<const Expr *> Privates,
+    ArrayRef<const Expr *> LHSExprs, ArrayRef<const Expr *> RHSExprs,
   auto &C = CGM.getContext();
 
   // void reduction_func(void *LHSArg, void *RHSArg);
   FunctionArgList Args;
   ImplicitParamDecl LHSArg(C, /*DC=*/nullptr, SourceLocation(), /*Id=*/nullptr,
                            C.VoidPtrTy);
   ImplicitParamDecl RHSArg(C, /*DC=*/nullptr, SourceLocation(), /*Id=*/nullptr,
                            C.VoidPtrTy);
for (auto *E : ReductionOps) {
     ++ILHS;
     ++IRHS;
   }
   Scope.ForceCleanup();
   CGF.FinishFunction();
   return Fn;
 }
 
-static void emitSingleReductionCombiner(CodeGenFunction &CGF,
+void CGOpenMPRuntime::emitSingleReductionCombiner(CodeGenFunction &CGF,
                                                   const Expr *ReductionOp,
                                                   const Expr *PrivateRef,
                                                   const DeclRefExpr *LHS,
                                                   const DeclRefExpr *RHS) {
   if (PrivateRef->getType()->isArrayType()) {
     // Emit reduction for array section.
     auto *LHSVar = cast<VarDecl>(LHS->getDecl());
     auto *RHSVar = cast<VarDecl>(RHS->getDecl());
     EmitOMPAggregateReduction(
         CGF, PrivateRef->getType(), LHSVar, RHSVar,
         [=](CodeGenFunction &CGF, const Expr *, const Expr *, const Expr *) {
           emitReductionCombiner(CGF, ReductionOp);
         });
   } else
     // Emit reduction for array subscript or single variable.
     emitReductionCombiner(CGF, ReductionOp);
 }
 
 void CGOpenMPRuntime::emitReduction(CodeGenFunction &CGF, SourceLocation Loc,
                                     ArrayRef<const Expr *> Privates,
                                     ArrayRef<const Expr *> LHSExprs,
                                     ArrayRef<const Expr *> RHSExprs,
                                     ArrayRef<const Expr *> ReductionOps,
-                                    bool WithNowait, bool SimpleReduction) {
+                                    ReductionOptionsTy Options) {
   if (!CGF.HaveInsertPoint())
     return;
+
+  bool WithNowait = Options.WithNowait;
+  bool SimpleReduction = Options.SimpleReduction;
+
   // Next code should be emitted for reduction:
   //
   // static kmp_critical_name lock = { 0 };
   //
   // void reduce_func(void *lhs[<n>], void *rhs[<n>]) {
   //  *(Type0*)lhs[0] = ReductionOperation0(*(Type0*)lhs[0], *(Type0*)rhs[0]);
   //  ...
   //  *(Type<n>-1*)lhs[<n>-1] = ReductionOperation<n>-1(*(Type<n>-1*)lhs[<n>-1],
void CGOpenMPRuntime::emitReduction(CodeGenFunction &CGF, SourceLocation Loc,
   // Add emission of __kmpc_end_reduce{_nowait}(<loc>, <gtid>, &<lock>);
   llvm::Value *EndArgs[] = {
       IdentTLoc, // ident_t *<loc>
       ThreadId,  // i32 <gtid>
       Lock       // kmp_critical_name *&<lock>
   };
   auto &&CodeGen = [&Privates, &LHSExprs, &RHSExprs, &ReductionOps](
       CodeGenFunction &CGF, PrePostActionTy &Action) {
+    auto &RT = CGF.CGM.getOpenMPRuntime();
     auto IPriv = Privates.begin();
     auto ILHS = LHSExprs.begin();
     auto IRHS = RHSExprs.begin();
     for (auto *E : ReductionOps) {
-      emitSingleReductionCombiner(CGF, E, *IPriv, cast<DeclRefExpr>(*ILHS),
+      RT.emitSingleReductionCombiner(CGF, E, *IPriv, cast<DeclRefExpr>(*ILHS),
                                      cast<DeclRefExpr>(*IRHS));
       ++IPriv;
       ++ILHS;
       ++IRHS;
     }
   };
   RegionCodeGenTy RCG(CodeGen);
   CommonActionTy Action(
       nullptr, llvm::None,

cfe/trunk/lib/CodeGen/CGOpenMPRuntimeNVPTX.h

private:
 
   /// \brief Helper for Spmd mode target directive's entry function.
   void emitSpmdEntryHeader(CodeGenFunction &CGF, EntryFunctionState &EST,
                            const OMPExecutableDirective &D);
 
   /// \brief Signal termination of Spmd mode execution.
   void emitSpmdEntryFooter(CodeGenFunction &CGF, EntryFunctionState &EST);
 
-  /// \brief Returns specified OpenMP runtime function for the current OpenMP
-  /// implementation.  Specialized for the NVPTX device.
-  /// \param Function OpenMP runtime function.
-  /// \return Specified function.
-  llvm::Constant *createNVPTXRuntimeFunction(unsigned Function);
-
   //
   // Base class overrides.
   //
 
   /// \brief Creates offloading entry for the provided entry ID \a ID,
   /// address \a Addr, size \a Size, and flags \a Flags.
   void createOffloadEntry(llvm::Constant *ID, llvm::Constant *Addr,
                           uint64_t Size, int32_t Flags = 0) override;
public:
   /// variables used in \a OutlinedFn function.
   /// \param IfCond Condition in the associated 'if' clause, if it was
   /// specified, nullptr otherwise.
   void emitParallelCall(CodeGenFunction &CGF, SourceLocation Loc,
                         llvm::Value *OutlinedFn,
                         ArrayRef<llvm::Value *> CapturedVars,
                         const Expr *IfCond) override;
 
-public:
+  /// Emit a code for reduction clause.
+  ///
+  /// \param Privates List of private copies for original reduction arguments.
+  /// \param LHSExprs List of LHS in \a ReductionOps reduction operations.
+  /// \param RHSExprs List of RHS in \a ReductionOps reduction operations.
+  /// \param ReductionOps List of reduction operations in form 'LHS binop RHS'
+  /// or 'operator binop(LHS, RHS)'.
+  /// \param Options List of options for reduction codegen:
+  ///     WithNowait true if parent directive has also nowait clause, false
+  ///     otherwise.
+  ///     SimpleReduction Emit reduction operation only. Used for omp simd
+  ///     directive on the host.
+  ///     ReductionKind The kind of reduction to perform.
+  virtual void emitReduction(CodeGenFunction &CGF, SourceLocation Loc,
+                             ArrayRef<const Expr *> Privates,
+                             ArrayRef<const Expr *> LHSExprs,
+                             ArrayRef<const Expr *> RHSExprs,
+                             ArrayRef<const Expr *> ReductionOps,
+                             ReductionOptionsTy Options) override;
+
+  /// Returns specified OpenMP runtime function for the current OpenMP
+  /// implementation.  Specialized for the NVPTX device.
+  /// \param Function OpenMP runtime function.
+  /// \return Specified function.
+  llvm::Constant *createNVPTXRuntimeFunction(unsigned Function);
+
   /// Target codegen is specialized based on two programming models: the
   /// 'generic' fork-join model of OpenMP, and a more GPU efficient 'spmd'
   /// model for constructs like 'target parallel' that support it.
   enum ExecutionMode {
     /// Single Program Multiple Data.
     Spmd,
     /// Generic codegen to support fork-join model.
     Generic,

cfe/trunk/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp

enum OpenMPRTLFunctionNVPTX {
   /// \brief Call to void __kmpc_kernel_end_parallel();
   OMPRTL_NVPTX__kmpc_kernel_end_parallel,
   /// Call to void __kmpc_serialized_parallel(ident_t *loc, kmp_int32
   /// global_tid);
   OMPRTL_NVPTX__kmpc_serialized_parallel,
   /// Call to void __kmpc_end_serialized_parallel(ident_t *loc, kmp_int32
   /// global_tid);
   OMPRTL_NVPTX__kmpc_end_serialized_parallel,
+  /// \brief Call to int32_t __kmpc_shuffle_int32(int32_t element,
+  /// int16_t lane_offset, int16_t warp_size);
+  OMPRTL_NVPTX__kmpc_shuffle_int32,
+  /// \brief Call to int64_t __kmpc_shuffle_int64(int64_t element,
+  /// int16_t lane_offset, int16_t warp_size);
+  OMPRTL_NVPTX__kmpc_shuffle_int64,
+  /// \brief Call to __kmpc_nvptx_parallel_reduce_nowait(kmp_int32
+  /// global_tid, kmp_int32 num_vars, size_t reduce_size, void* reduce_data,
+  /// void (*kmp_ShuffleReductFctPtr)(void *rhsData, int16_t lane_id, int16_t
+  /// lane_offset, int16_t shortCircuit),
+  /// void (*kmp_InterWarpCopyFctPtr)(void* src, int32_t warp_num));
+  OMPRTL_NVPTX__kmpc_parallel_reduce_nowait,
+  /// \brief Call to __kmpc_nvptx_end_reduce_nowait(int32_t global_tid);
+  OMPRTL_NVPTX__kmpc_end_reduce_nowait
 };
 
 /// Pre(post)-action for different OpenMP constructs specialized for NVPTX.
 class NVPTXActionTy final : public PrePostActionTy {
   llvm::Value *EnterCallee;
   ArrayRef<llvm::Value *> EnterArgs;
   llvm::Value *ExitCallee;
   ArrayRef<llvm::Value *> ExitArgs;
public:
   ExecutionModeRAII(CGOpenMPRuntimeNVPTX::ExecutionMode &Mode,
                     CGOpenMPRuntimeNVPTX::ExecutionMode NewMode)
       : Mode(Mode) {
     SavedMode = Mode;
     Mode = NewMode;
   }
   ~ExecutionModeRAII() { Mode = SavedMode; }
 };
+
+/// GPU Configuration:  This information can be derived from cuda registers,
+/// however, providing compile time constants helps generate more efficient
+/// code.  For all practical purposes this is fine because the configuration
+/// is the same for all known NVPTX architectures.
+enum MachineConfiguration : unsigned {
+  WarpSize = 32,
+  /// Number of bits required to represent a lane identifier, which is
+  /// computed as log_2(WarpSize).
+  LaneIDBits = 5,
+  LaneIDMask = WarpSize - 1,
+};
+
+enum NamedBarrier : unsigned {
+  /// Synchronize on this barrier #ID using a named barrier primitive.
+  /// Only the subset of active threads in a parallel region arrive at the
+  /// barrier.
+  NB_Parallel = 1,
+};
 } // anonymous namespace
 
 /// Get the GPU warp size.
 static llvm::Value *getNVPTXWarpSize(CodeGenFunction &CGF) {
   CGBuilderTy &Bld = CGF.Builder;
   return Bld.CreateCall(
       llvm::Intrinsic::getDeclaration(
           &CGF.CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_warpsize),
       llvm::None, "nvptx_warp_size");
 }
 
 /// Get the id of the current thread on the GPU.
 static llvm::Value *getNVPTXThreadID(CodeGenFunction &CGF) {
   CGBuilderTy &Bld = CGF.Builder;
   return Bld.CreateCall(
       llvm::Intrinsic::getDeclaration(
           &CGF.CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_tid_x),
       llvm::None, "nvptx_tid");
 }
 
+/// Get the id of the warp in the block.
+/// We assume that the warp size is 32, which is always the case
+/// on the NVPTX device, to generate more efficient code.
+static llvm::Value *getNVPTXWarpID(CodeGenFunction &CGF) {
+  CGBuilderTy &Bld = CGF.Builder;
+  return Bld.CreateAShr(getNVPTXThreadID(CGF), LaneIDBits, "nvptx_warp_id");
+}
+
+/// Get the id of the current lane in the Warp.
+/// We assume that the warp size is 32, which is always the case
+/// on the NVPTX device, to generate more efficient code.
+static llvm::Value *getNVPTXLaneID(CodeGenFunction &CGF) {
+  CGBuilderTy &Bld = CGF.Builder;
+  return Bld.CreateAnd(getNVPTXThreadID(CGF), Bld.getInt32(LaneIDMask),
+                       "nvptx_lane_id");
+}
+
 /// Get the maximum number of threads in a block of the GPU.
 static llvm::Value *getNVPTXNumThreads(CodeGenFunction &CGF) {
   CGBuilderTy &Bld = CGF.Builder;
   return Bld.CreateCall(
       llvm::Intrinsic::getDeclaration(
           &CGF.CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_ntid_x),
       llvm::None, "nvptx_num_threads");
 }
 
 /// Get barrier to synchronize all threads in a block.
 static void getNVPTXCTABarrier(CodeGenFunction &CGF) {
   CGBuilderTy &Bld = CGF.Builder;
   Bld.CreateCall(llvm::Intrinsic::getDeclaration(
       &CGF.CGM.getModule(), llvm::Intrinsic::nvvm_barrier0));
 }
 
+/// Get barrier #ID to synchronize selected (multiple of warp size) threads in
+/// a CTA.
+static void getNVPTXBarrier(CodeGenFunction &CGF, int ID,
+                            llvm::Value *NumThreads) {
+  CGBuilderTy &Bld = CGF.Builder;
+  llvm::Value *Args[] = {Bld.getInt32(ID), NumThreads};
+  Bld.CreateCall(llvm::Intrinsic::getDeclaration(&CGF.CGM.getModule(),
+                                                 llvm::Intrinsic::nvvm_barrier),
+                 Args);
+}
+
 /// Synchronize all GPU threads in a block.
 static void syncCTAThreads(CodeGenFunction &CGF) { getNVPTXCTABarrier(CGF); }
 
+/// Synchronize worker threads in a parallel region.
+static void syncParallelThreads(CodeGenFunction &CGF, llvm::Value *NumThreads) {
+  return getNVPTXBarrier(CGF, NB_Parallel, NumThreads);
+}
+
 /// Get the value of the thread_limit clause in the teams directive.
 /// For the 'generic' execution mode, the runtime encodes thread_limit in
 /// the launch parameters, always starting thread_limit+warpSize threads per
 /// CTA. The threads in the last warp are reserved for master execution.
 /// For the 'spmd' execution mode, all threads in a CTA are part of the team.
 static llvm::Value *getThreadLimit(CodeGenFunction &CGF,
                                    bool IsInSpmdExecutionMode = false) {
   CGBuilderTy &Bld = CGF.Builder;
case OMPRTL_NVPTX__kmpc_end_serialized_parallel: {
     // Build void __kmpc_end_serialized_parallel(ident_t *loc, kmp_int32
     // global_tid);
     llvm::Type *TypeParams[] = {getIdentTyPointerTy(), CGM.Int32Ty};
     llvm::FunctionType *FnTy =
         llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
     RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_end_serialized_parallel");
     break;
   }
+  case OMPRTL_NVPTX__kmpc_shuffle_int32: {
+    // Build int32_t __kmpc_shuffle_int32(int32_t element,
+    // int16_t lane_offset, int16_t warp_size);
+    llvm::Type *TypeParams[] = {CGM.Int32Ty, CGM.Int16Ty, CGM.Int16Ty};
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(CGM.Int32Ty, TypeParams, /*isVarArg*/ false);
+    RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_shuffle_int32");
+    break;
+  }
+  case OMPRTL_NVPTX__kmpc_shuffle_int64: {
+    // Build int64_t __kmpc_shuffle_int64(int64_t element,
+    // int16_t lane_offset, int16_t warp_size);
+    llvm::Type *TypeParams[] = {CGM.Int64Ty, CGM.Int16Ty, CGM.Int16Ty};
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(CGM.Int64Ty, TypeParams, /*isVarArg*/ false);
+    RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_shuffle_int64");
+    break;
+  }
+  case OMPRTL_NVPTX__kmpc_parallel_reduce_nowait: {
+    // Build int32_t kmpc_nvptx_parallel_reduce_nowait(kmp_int32 global_tid,
+    // kmp_int32 num_vars, size_t reduce_size, void* reduce_data,
+    // void (*kmp_ShuffleReductFctPtr)(void *rhsData, int16_t lane_id, int16_t
+    // lane_offset, int16_t Algorithm Version),
+    // void (*kmp_InterWarpCopyFctPtr)(void* src, int warp_num));
+    llvm::Type *ShuffleReduceTypeParams[] = {CGM.VoidPtrTy, CGM.Int16Ty,
+                                             CGM.Int16Ty, CGM.Int16Ty};
+    auto *ShuffleReduceFnTy =
+        llvm::FunctionType::get(CGM.VoidTy, ShuffleReduceTypeParams,
+                                /*isVarArg=*/false);
+    llvm::Type *InterWarpCopyTypeParams[] = {CGM.VoidPtrTy, CGM.Int32Ty};
+    auto *InterWarpCopyFnTy =
+        llvm::FunctionType::get(CGM.VoidTy, InterWarpCopyTypeParams,
+                                /*isVarArg=*/false);
+    llvm::Type *TypeParams[] = {CGM.Int32Ty,
+                                CGM.Int32Ty,
+                                CGM.SizeTy,
+                                CGM.VoidPtrTy,
+                                ShuffleReduceFnTy->getPointerTo(),
+                                InterWarpCopyFnTy->getPointerTo()};
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(CGM.Int32Ty, TypeParams, /*isVarArg=*/false);
+    RTLFn = CGM.CreateRuntimeFunction(
+        FnTy, /*Name=*/"__kmpc_nvptx_parallel_reduce_nowait");
+    break;
+  }
+  case OMPRTL_NVPTX__kmpc_end_reduce_nowait: {
+    // Build __kmpc_end_reduce_nowait(kmp_int32 global_tid);
+    llvm::Type *TypeParams[] = {CGM.Int32Ty};
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg=*/false);
+    RTLFn = CGM.CreateRuntimeFunction(
+        FnTy, /*Name=*/"__kmpc_nvptx_end_reduce_nowait");
+    break;
+  }
   }
   return RTLFn;
 }
 
 void CGOpenMPRuntimeNVPTX::createOffloadEntry(llvm::Constant *ID,
                                               llvm::Constant *Addr,
                                               uint64_t Size, int32_t) {
   auto *F = dyn_cast<llvm::Function>(Addr);
void CGOpenMPRuntimeNVPTX::emitSpmdParallelCall(
   llvm::SmallVector<llvm::Value *, 16> OutlinedFnArgs;
   OutlinedFnArgs.push_back(
       llvm::ConstantPointerNull::get(CGM.Int32Ty->getPointerTo()));
   OutlinedFnArgs.push_back(
       llvm::ConstantPointerNull::get(CGM.Int32Ty->getPointerTo()));
   OutlinedFnArgs.append(CapturedVars.begin(), CapturedVars.end());
   CGF.EmitCallOrInvoke(OutlinedFn, OutlinedFnArgs);
 }
+
+/// This function creates calls to one of two shuffle functions to copy
+/// variables between lanes in a warp.
+static llvm::Value *createRuntimeShuffleFunction(CodeGenFunction &CGF,
+                                                 QualType ElemTy,
+                                                 llvm::Value *Elem,
+                                                 llvm::Value *Offset) {
+  auto &CGM = CGF.CGM;
+  auto &C = CGM.getContext();
+  auto &Bld = CGF.Builder;
+  CGOpenMPRuntimeNVPTX &RT =
+      *(static_cast<CGOpenMPRuntimeNVPTX *>(&CGM.getOpenMPRuntime()));
+
+  unsigned Size = CGM.getContext().getTypeSizeInChars(ElemTy).getQuantity();
+  assert(Size <= 8 && "Unsupported bitwidth in shuffle instruction.");
+
+  OpenMPRTLFunctionNVPTX ShuffleFn = Size <= 4
+                                         ? OMPRTL_NVPTX__kmpc_shuffle_int32
+                                         : OMPRTL_NVPTX__kmpc_shuffle_int64;
+
+  // Cast all types to 32- or 64-bit values before calling shuffle routines.
+  auto CastTy = Size <= 4 ? CGM.Int32Ty : CGM.Int64Ty;
+  auto *ElemCast = Bld.CreateSExtOrBitCast(Elem, CastTy);
+  auto *WarpSize = CGF.EmitScalarConversion(
+      getNVPTXWarpSize(CGF), C.getIntTypeForBitwidth(32, /* Signed */ true),
+      C.getIntTypeForBitwidth(16, /* Signed */ true), SourceLocation());
+
+  auto *ShuffledVal =
+      CGF.EmitRuntimeCall(RT.createNVPTXRuntimeFunction(ShuffleFn),
+                          {ElemCast, Offset, WarpSize});
+
+  return Bld.CreateTruncOrBitCast(ShuffledVal, CGF.ConvertTypeForMem(ElemTy));
+}
+
+namespace {
+enum CopyAction : unsigned {
+  // RemoteLaneToThread: Copy over a Reduce list from a remote lane in
+  // the warp using shuffle instructions.
+  RemoteLaneToThread,
+  // ThreadCopy: Make a copy of a Reduce list on the thread's stack.
+  ThreadCopy,
+};
+} // namespace
+
+/// Emit instructions to copy a Reduce list, which contains partially
+/// aggregated values, in the specified direction.
+static void emitReductionListCopy(CopyAction Action, CodeGenFunction &CGF,
+                                  QualType ReductionArrayTy,
+                                  ArrayRef<const Expr *> Privates,
+                                  Address SrcBase, Address DestBase,
+                                  llvm::Value *RemoteLaneOffset = nullptr) {
+
+  auto &CGM = CGF.CGM;
+  auto &C = CGM.getContext();
+  auto &Bld = CGF.Builder;
+
+  // Iterates, element-by-element, through the source Reduce list and
+  // make a copy.
+  unsigned Idx = 0;
+  for (auto &Private : Privates) {
+    Address SrcElementAddr = Address::invalid();
+    Address DestElementAddr = Address::invalid();
+    Address DestElementPtrAddr = Address::invalid();
+    // Should we shuffle in an element from a remote lane?
+    bool ShuffleInElement = false;
+    // Set to true to update the pointer in the dest Reduce list to a
+    // newly created element.
+    bool UpdateDestListPtr = false;
+
+    switch (Action) {
+    case RemoteLaneToThread: {
+      // Step 1.1: Get the address for the src element in the Reduce list.
+      Address SrcElementPtrAddr =
+          Bld.CreateConstArrayGEP(SrcBase, Idx, CGF.getPointerSize());
+      llvm::Value *SrcElementPtrPtr = CGF.EmitLoadOfScalar(
+          SrcElementPtrAddr, /*Volatile=*/false, C.VoidPtrTy, SourceLocation());
+      SrcElementAddr =
+          Address(SrcElementPtrPtr, C.getTypeAlignInChars(Private->getType()));
+
+      // Step 1.2: Create a temporary to store the element in the destination
+      // Reduce list.
+      DestElementPtrAddr =
+          Bld.CreateConstArrayGEP(DestBase, Idx, CGF.getPointerSize());
+      DestElementAddr =
+          CGF.CreateMemTemp(Private->getType(), ".omp.reduction.element");
+      ShuffleInElement = true;
+      UpdateDestListPtr = true;
+      break;
+    }
+    case ThreadCopy: {
+      // Step 1.1: Get the address for the src element in the Reduce list.
+      Address SrcElementPtrAddr =
+          Bld.CreateConstArrayGEP(SrcBase, Idx, CGF.getPointerSize());
+      llvm::Value *SrcElementPtrPtr = CGF.EmitLoadOfScalar(
+          SrcElementPtrAddr, /*Volatile=*/false, C.VoidPtrTy, SourceLocation());
+      SrcElementAddr =
+          Address(SrcElementPtrPtr, C.getTypeAlignInChars(Private->getType()));
+
+      // Step 1.2: Get the address for dest element.  The destination
+      // element has already been created on the thread's stack.
+      DestElementPtrAddr =
+          Bld.CreateConstArrayGEP(DestBase, Idx, CGF.getPointerSize());
+      llvm::Value *DestElementPtr =
+          CGF.EmitLoadOfScalar(DestElementPtrAddr, /*Volatile=*/false,
+                               C.VoidPtrTy, SourceLocation());
+      Address DestElemAddr =
+          Address(DestElementPtr, C.getTypeAlignInChars(Private->getType()));
+      DestElementAddr = Bld.CreateElementBitCast(
+          DestElemAddr, CGF.ConvertTypeForMem(Private->getType()));
+      break;
+    }
+    }
+
+    // Regardless of src and dest of copy, we emit the load of src
+    // element as this is required in all directions
+    SrcElementAddr = Bld.CreateElementBitCast(
+        SrcElementAddr, CGF.ConvertTypeForMem(Private->getType()));
+    llvm::Value *Elem =
+        CGF.EmitLoadOfScalar(SrcElementAddr, /*Volatile=*/false,
+                             Private->getType(), SourceLocation());
+
+    // Now that all active lanes have read the element in the
+    // Reduce list, shuffle over the value from the remote lane.
+    if (ShuffleInElement) {
+      Elem = createRuntimeShuffleFunction(CGF, Private->getType(), Elem,
+                                          RemoteLaneOffset);
+    }
+
+    // Store the source element value to the dest element address.
+    CGF.EmitStoreOfScalar(Elem, DestElementAddr, /*Volatile=*/false,
+                          Private->getType());
+
+    // Step 3.1: Modify reference in dest Reduce list as needed.
+    // Modifying the reference in Reduce list to point to the newly
+    // created element.  The element is live in the current function
+    // scope and that of functions it invokes (i.e., reduce_function).
+    // RemoteReduceData[i] = (void*)&RemoteElem
+    if (UpdateDestListPtr) {
+      CGF.EmitStoreOfScalar(Bld.CreatePointerBitCastOrAddrSpaceCast(
+                                DestElementAddr.getPointer(), CGF.VoidPtrTy),
+                            DestElementPtrAddr, /*Volatile=*/false,
+                            C.VoidPtrTy);
+    }
+
+    Idx++;
+  }
+}
+
+/// This function emits a helper that gathers Reduce lists from the first
+/// lane of every active warp to lanes in the first warp.
+///
+/// void inter_warp_copy_func(void* reduce_data, num_warps)
+///   shared smem[warp_size];
+///   For all data entries D in reduce_data:
+///     If (I am the first lane in each warp)
+///       Copy my local D to smem[warp_id]
+///     sync
+///     if (I am the first warp)
+///       Copy smem[thread_id] to my local D
+///     sync
+static llvm::Value *emitInterWarpCopyFunction(CodeGenModule &CGM,
+                                              ArrayRef<const Expr *> Privates,
+                                              QualType ReductionArrayTy) {
+  auto &C = CGM.getContext();
+  auto &M = CGM.getModule();
+
+  // ReduceList: thread local Reduce list.
+  // At the stage of the computation when this function is called, partially
+  // aggregated values reside in the first lane of every active warp.
+  ImplicitParamDecl ReduceListArg(C, /*DC=*/nullptr, SourceLocation(),
+                                  /*Id=*/nullptr, C.VoidPtrTy);
+  // NumWarps: number of warps active in the parallel region.  This could
+  // be smaller than 32 (max warps in a CTA) for partial block reduction.
+  ImplicitParamDecl NumWarpsArg(C, /*DC=*/nullptr, SourceLocation(),
+                                /*Id=*/nullptr,
+                                C.getIntTypeForBitwidth(32, /* Signed */ true));
+  FunctionArgList Args;
+  Args.push_back(&ReduceListArg);
+  Args.push_back(&NumWarpsArg);
+
+  auto &CGFI = CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, Args);
+  auto *Fn = llvm::Function::Create(
+      CGM.getTypes().GetFunctionType(CGFI), llvm::GlobalValue::InternalLinkage,
+      "_omp_reduction_inter_warp_copy_func", &CGM.getModule());
+  CGM.SetInternalFunctionAttributes(/*DC=*/nullptr, Fn, CGFI);
+  CodeGenFunction CGF(CGM);
+  // We don't need debug information in this function as nothing here refers to
+  // user code.
+  CGF.disableDebugInfo();
+  CGF.StartFunction(GlobalDecl(), C.VoidTy, Fn, CGFI, Args);
+
+  auto &Bld = CGF.Builder;
+
+  // This array is used as a medium to transfer, one reduce element at a time,
+  // the data from the first lane of every warp to lanes in the first warp
+  // in order to perform the final step of a reduction in a parallel region
+  // (reduction across warps).  The array is placed in NVPTX __shared__ memory
+  // for reduced latency, as well as to have a distinct copy for concurrently
+  // executing target regions.  The array is declared with common linkage so
+  // as to be shared across compilation units.
+  const char *TransferMediumName =
+      "__openmp_nvptx_data_transfer_temporary_storage";
+  llvm::GlobalVariable *TransferMedium =
+      M.getGlobalVariable(TransferMediumName);
+  if (!TransferMedium) {
+    auto *Ty = llvm::ArrayType::get(CGM.Int64Ty, WarpSize);
+    unsigned SharedAddressSpace = C.getTargetAddressSpace(LangAS::cuda_shared);
+    TransferMedium = new llvm::GlobalVariable(
+        M, Ty,
+        /*isConstant=*/false, llvm::GlobalVariable::CommonLinkage,
+        llvm::Constant::getNullValue(Ty), TransferMediumName,
+        /*InsertBefore=*/nullptr, llvm::GlobalVariable::NotThreadLocal,
+        SharedAddressSpace);
+  }
+
+  // Get the CUDA thread id of the current OpenMP thread on the GPU.
+  auto *ThreadID = getNVPTXThreadID(CGF);
+  // nvptx_lane_id = nvptx_id % warpsize
+  auto *LaneID = getNVPTXLaneID(CGF);
+  // nvptx_warp_id = nvptx_id / warpsize
+  auto *WarpID = getNVPTXWarpID(CGF);
+
+  Address AddrReduceListArg = CGF.GetAddrOfLocalVar(&ReduceListArg);
+  Address LocalReduceList(
+      Bld.CreatePointerBitCastOrAddrSpaceCast(
+          CGF.EmitLoadOfScalar(AddrReduceListArg, /*Volatile=*/false,
+                               C.VoidPtrTy, SourceLocation()),
+          CGF.ConvertTypeForMem(ReductionArrayTy)->getPointerTo()),
+      CGF.getPointerAlign());
+
+  unsigned Idx = 0;
+  for (auto &Private : Privates) {
+    //
+    // Warp master copies reduce element to transfer medium in __shared__
+    // memory.
+    //
+    llvm::BasicBlock *ThenBB = CGF.createBasicBlock("then");
+    llvm::BasicBlock *ElseBB = CGF.createBasicBlock("else");
+    llvm::BasicBlock *MergeBB = CGF.createBasicBlock("ifcont");
+
+    // if (lane_id == 0)
+    auto IsWarpMaster =
+        Bld.CreateICmpEQ(LaneID, Bld.getInt32(0), "warp_master");
+    Bld.CreateCondBr(IsWarpMaster, ThenBB, ElseBB);
+    CGF.EmitBlock(ThenBB);
+
+    // Reduce element = LocalReduceList[i]
+    Address ElemPtrPtrAddr =
+        Bld.CreateConstArrayGEP(LocalReduceList, Idx, CGF.getPointerSize());
+    llvm::Value *ElemPtrPtr = CGF.EmitLoadOfScalar(
+        ElemPtrPtrAddr, /*Volatile=*/false, C.VoidPtrTy, SourceLocation());
+    // elemptr = (type[i]*)(elemptrptr)
+    Address ElemPtr =
+        Address(ElemPtrPtr, C.getTypeAlignInChars(Private->getType()));
+    ElemPtr = Bld.CreateElementBitCast(
+        ElemPtr, CGF.ConvertTypeForMem(Private->getType()));
+    // elem = *elemptr
+    llvm::Value *Elem = CGF.EmitLoadOfScalar(
+        ElemPtr, /*Volatile=*/false, Private->getType(), SourceLocation());
+
+    // Get pointer to location in transfer medium.
+    // MediumPtr = &medium[warp_id]
+    llvm::Value *MediumPtrVal = Bld.CreateInBoundsGEP(
+        TransferMedium, {llvm::Constant::getNullValue(CGM.Int64Ty), WarpID});
+    Address MediumPtr(MediumPtrVal, C.getTypeAlignInChars(Private->getType()));
+    // Casting to actual data type.
+    // MediumPtr = (type[i]*)MediumPtrAddr;
+    MediumPtr = Bld.CreateElementBitCast(
+        MediumPtr, CGF.ConvertTypeForMem(Private->getType()));
+
+    //*MediumPtr = elem
+    Bld.CreateStore(Elem, MediumPtr);
+
+    Bld.CreateBr(MergeBB);
+
+    CGF.EmitBlock(ElseBB);
+    Bld.CreateBr(MergeBB);
+
+    CGF.EmitBlock(MergeBB);
+
+    Address AddrNumWarpsArg = CGF.GetAddrOfLocalVar(&NumWarpsArg);
+    llvm::Value *NumWarpsVal = CGF.EmitLoadOfScalar(
+        AddrNumWarpsArg, /*Volatile=*/false, C.IntTy, SourceLocation());
+
+    auto *NumActiveThreads = Bld.CreateNSWMul(
+        NumWarpsVal, getNVPTXWarpSize(CGF), "num_active_threads");
+    // named_barrier_sync(ParallelBarrierID, num_active_threads)
+    syncParallelThreads(CGF, NumActiveThreads);
+
+    //
+    // Warp 0 copies reduce element from transfer medium.
+    //
+    llvm::BasicBlock *W0ThenBB = CGF.createBasicBlock("then");
+    llvm::BasicBlock *W0ElseBB = CGF.createBasicBlock("else");
+    llvm::BasicBlock *W0MergeBB = CGF.createBasicBlock("ifcont");
+
+    // Up to 32 threads in warp 0 are active.
+    auto IsActiveThread =
+        Bld.CreateICmpULT(ThreadID, NumWarpsVal, "is_active_thread");
+    Bld.CreateCondBr(IsActiveThread, W0ThenBB, W0ElseBB);
+
+    CGF.EmitBlock(W0ThenBB);
+
+    // SrcMediumPtr = &medium[tid]
+    llvm::Value *SrcMediumPtrVal = Bld.CreateInBoundsGEP(
+        TransferMedium, {llvm::Constant::getNullValue(CGM.Int64Ty), ThreadID});
+    Address SrcMediumPtr(SrcMediumPtrVal,
+                         C.getTypeAlignInChars(Private->getType()));
+    // SrcMediumVal = *SrcMediumPtr;
+    SrcMediumPtr = Bld.CreateElementBitCast(
+        SrcMediumPtr, CGF.ConvertTypeForMem(Private->getType()));
+    llvm::Value *SrcMediumValue = CGF.EmitLoadOfScalar(
+        SrcMediumPtr, /*Volatile=*/false, Private->getType(), SourceLocation());
+
+    // TargetElemPtr = (type[i]*)(SrcDataAddr[i])
+    Address TargetElemPtrPtr =
+        Bld.CreateConstArrayGEP(LocalReduceList, Idx, CGF.getPointerSize());
+    llvm::Value *TargetElemPtrVal = CGF.EmitLoadOfScalar(
+        TargetElemPtrPtr, /*Volatile=*/false, C.VoidPtrTy, SourceLocation());
+    Address TargetElemPtr =
+        Address(TargetElemPtrVal, C.getTypeAlignInChars(Private->getType()));
+    TargetElemPtr = Bld.CreateElementBitCast(
+        TargetElemPtr, CGF.ConvertTypeForMem(Private->getType()));
+
+    // *TargetElemPtr = SrcMediumVal;
+    CGF.EmitStoreOfScalar(SrcMediumValue, TargetElemPtr, /*Volatile=*/false,
+                          Private->getType());
+    Bld.CreateBr(W0MergeBB);
+
+    CGF.EmitBlock(W0ElseBB);
+    Bld.CreateBr(W0MergeBB);
+
+    CGF.EmitBlock(W0MergeBB);
+
+    // While warp 0 copies values from transfer medium, all other warps must
+    // wait.
+    syncParallelThreads(CGF, NumActiveThreads);
+    Idx++;
+  }
+
+  CGF.FinishFunction();
+  return Fn;
+}
+
+/// Emit a helper that reduces data across two OpenMP threads (lanes)
+/// in the same warp.  It uses shuffle instructions to copy over data from
+/// a remote lane's stack.  The reduction algorithm performed is specified
+/// by the fourth parameter.
+///
+/// Algorithm Versions.
+/// Full Warp Reduce (argument value 0):
+///   This algorithm assumes that all 32 lanes are active and gathers
+///   data from these 32 lanes, producing a single resultant value.
+/// Contiguous Partial Warp Reduce (argument value 1):
+///   This algorithm assumes that only a *contiguous* subset of lanes
+///   are active.  This happens for the last warp in a parallel region
+///   when the user specified num_threads is not an integer multiple of
+///   32.  This contiguous subset always starts with the zeroth lane.
+/// Partial Warp Reduce (argument value 2):
+///   This algorithm gathers data from any number of lanes at any position.
+/// All reduced values are stored in the lowest possible lane.  The set
+/// of problems every algorithm addresses is a super set of those
+/// addressable by algorithms with a lower version number.  Overhead
+/// increases as algorithm version increases.
+///
+/// Terminology
+/// Reduce element:
+///   Reduce element refers to the individual data field with primitive
+///   data types to be combined and reduced across threads.
+/// Reduce list:
+///   Reduce list refers to a collection of local, thread-private
+///   reduce elements.
+/// Remote Reduce list:
+///   Remote Reduce list refers to a collection of remote (relative to
+///   the current thread) reduce elements.
+///
+/// We distinguish between three states of threads that are important to
+/// the implementation of this function.
+/// Alive threads:
+///   Threads in a warp executing the SIMT instruction, as distinguished from
+///   threads that are inactive due to divergent control flow.
+/// Active threads:
+///   The minimal set of threads that has to be alive upon entry to this
+///   function.  The computation is correct iff active threads are alive.
+///   Some threads are alive but they are not active because they do not
+///   contribute to the computation in any useful manner.  Turning them off
+///   may introduce control flow overheads without any tangible benefits.
+/// Effective threads:
+///   In order to comply with the argument requirements of the shuffle
+///   function, we must keep all lanes holding data alive.  But at most
+///   half of them perform value aggregation; we refer to this half of
+///   threads as effective. The other half is simply handing off their
+///   data.
+///
+/// Procedure
+/// Value shuffle:
+///   In this step active threads transfer data from higher lane positions
+///   in the warp to lower lane positions, creating Remote Reduce list.
+/// Value aggregation:
+///   In this step, effective threads combine their thread local Reduce list
+///   with Remote Reduce list and store the result in the thread local
+///   Reduce list.
+/// Value copy:
+///   In this step, we deal with the assumption made by algorithm 2
+///   (i.e. contiguity assumption).  When we have an odd number of lanes
+///   active, say 2k+1, only k threads will be effective and therefore k
+///   new values will be produced.  However, the Reduce list owned by the
+///   (2k+1)th thread is ignored in the value aggregation.  Therefore
+///   we copy the Reduce list from the (2k+1)th lane to (k+1)th lane so
+///   that the contiguity assumption still holds.
+static llvm::Value *
+emitShuffleAndReduceFunction(CodeGenModule &CGM,
+                             ArrayRef<const Expr *> Privates,
+                             QualType ReductionArrayTy, llvm::Value *ReduceFn) {
+  auto &C = CGM.getContext();
+
+  // Thread local Reduce list used to host the values of data to be reduced.
+  ImplicitParamDecl ReduceListArg(C, /*DC=*/nullptr, SourceLocation(),
+                                  /*Id=*/nullptr, C.VoidPtrTy);
+  // Current lane id; could be logical.
+  ImplicitParamDecl LaneIDArg(C, /*DC=*/nullptr, SourceLocation(),
+                              /*Id=*/nullptr, C.ShortTy);
+  // Offset of the remote source lane relative to the current lane.
+  ImplicitParamDecl RemoteLaneOffsetArg(C, /*DC=*/nullptr, SourceLocation(),
+                                        /*Id=*/nullptr, C.ShortTy);
+  // Algorithm version.  This is expected to be known at compile time.
+  ImplicitParamDecl AlgoVerArg(C, /*DC=*/nullptr, SourceLocation(),
+                               /*Id=*/nullptr, C.ShortTy);
+  FunctionArgList Args;
+  Args.push_back(&ReduceListArg);
+  Args.push_back(&LaneIDArg);
+  Args.push_back(&RemoteLaneOffsetArg);
+  Args.push_back(&AlgoVerArg);
+
+  auto &CGFI = CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, Args);
+  auto *Fn = llvm::Function::Create(
+      CGM.getTypes().GetFunctionType(CGFI), llvm::GlobalValue::InternalLinkage,
+      "_omp_reduction_shuffle_and_reduce_func", &CGM.getModule());
+  CGM.SetInternalFunctionAttributes(/*D=*/nullptr, Fn, CGFI);
+  CodeGenFunction CGF(CGM);
+  // We don't need debug information in this function as nothing here refers to
+  // user code.
+  CGF.disableDebugInfo();
+  CGF.StartFunction(GlobalDecl(), C.VoidTy, Fn, CGFI, Args);
+
+  auto &Bld = CGF.Builder;
+
+  Address AddrReduceListArg = CGF.GetAddrOfLocalVar(&ReduceListArg);
+  Address LocalReduceList(
+      Bld.CreatePointerBitCastOrAddrSpaceCast(
+          CGF.EmitLoadOfScalar(AddrReduceListArg, /*Volatile=*/false,
+                               C.VoidPtrTy, SourceLocation()),
+          CGF.ConvertTypeForMem(ReductionArrayTy)->getPointerTo()),
+      CGF.getPointerAlign());
+
+  Address AddrLaneIDArg = CGF.GetAddrOfLocalVar(&LaneIDArg);
+  llvm::Value *LaneIDArgVal = CGF.EmitLoadOfScalar(
+      AddrLaneIDArg, /*Volatile=*/false, C.ShortTy, SourceLocation());
+
+  Address AddrRemoteLaneOffsetArg = CGF.GetAddrOfLocalVar(&RemoteLaneOffsetArg);
+  llvm::Value *RemoteLaneOffsetArgVal = CGF.EmitLoadOfScalar(
+      AddrRemoteLaneOffsetArg, /*Volatile=*/false, C.ShortTy, SourceLocation());
+
+  Address AddrAlgoVerArg = CGF.GetAddrOfLocalVar(&AlgoVerArg);
+  llvm::Value *AlgoVerArgVal = CGF.EmitLoadOfScalar(
+      AddrAlgoVerArg, /*Volatile=*/false, C.ShortTy, SourceLocation());
+
+  // Create a local thread-private variable to host the Reduce list
+  // from a remote lane.
+  Address RemoteReduceList =
+      CGF.CreateMemTemp(ReductionArrayTy, ".omp.reduction.remote_reduce_list");
+
+  // This loop iterates through the list of reduce elements and copies,
+  // element by element, from a remote lane in the warp to RemoteReduceList,
+  // hosted on the thread's stack.
+  emitReductionListCopy(RemoteLaneToThread, CGF, ReductionArrayTy, Privates,
+                        LocalReduceList, RemoteReduceList,
+                        RemoteLaneOffsetArgVal);
+
+  // The actions to be performed on the Remote Reduce list is dependent
+  // on the algorithm version.
+  //
+  //  if (AlgoVer==0) || (AlgoVer==1 && (LaneId < Offset)) || (AlgoVer==2 &&
+  //  LaneId % 2 == 0 && Offset > 0):
+  //    do the reduction value aggregation
+  //
+  //  The thread local variable Reduce list is mutated in place to host the
+  //  reduced data, which is the aggregated value produced from local and
+  //  remote lanes.
+  //
+  //  Note that AlgoVer is expected to be a constant integer known at compile
+  //  time.
+  //  When AlgoVer==0, the first conjunction evaluates to true, making
+  //    the entire predicate true during compile time.
+  //  When AlgoVer==1, the second conjunction has only the second part to be
+  //    evaluated during runtime.  Other conjunctions evaluates to false
+  //    during compile time.
+  //  When AlgoVer==2, the third conjunction has only the second part to be
+  //    evaluated during runtime.  Other conjunctions evaluates to false
+  //    during compile time.
+  auto CondAlgo0 = Bld.CreateICmpEQ(AlgoVerArgVal, Bld.getInt16(0));
+
+  auto CondAlgo1 =
+      Bld.CreateAnd(Bld.CreateICmpEQ(AlgoVerArgVal, Bld.getInt16(1)),
+                    Bld.CreateICmpULT(LaneIDArgVal, RemoteLaneOffsetArgVal));
+
+  auto CondAlgo2 = Bld.CreateAnd(
+      Bld.CreateICmpEQ(AlgoVerArgVal, Bld.getInt16(2)),
+      Bld.CreateICmpEQ(Bld.CreateAnd(LaneIDArgVal, Bld.getInt16(1)),
+                       Bld.getInt16(0)));
+  CondAlgo2 = Bld.CreateAnd(
+      CondAlgo2, Bld.CreateICmpSGT(RemoteLaneOffsetArgVal, Bld.getInt16(0)));
+
+  auto CondReduce = Bld.CreateOr(CondAlgo0, CondAlgo1);
+  CondReduce = Bld.CreateOr(CondReduce, CondAlgo2);
+
+  llvm::BasicBlock *ThenBB = CGF.createBasicBlock("then");
+  llvm::BasicBlock *ElseBB = CGF.createBasicBlock("else");
+  llvm::BasicBlock *MergeBB = CGF.createBasicBlock("ifcont");
+  Bld.CreateCondBr(CondReduce, ThenBB, ElseBB);
+
+  CGF.EmitBlock(ThenBB);
+  // reduce_function(LocalReduceList, RemoteReduceList)
+  llvm::Value *LocalReduceListPtr = Bld.CreatePointerBitCastOrAddrSpaceCast(
+      LocalReduceList.getPointer(), CGF.VoidPtrTy);
+  llvm::Value *RemoteReduceListPtr = Bld.CreatePointerBitCastOrAddrSpaceCast(
+      RemoteReduceList.getPointer(), CGF.VoidPtrTy);
+  CGF.EmitCallOrInvoke(ReduceFn, {LocalReduceListPtr, RemoteReduceListPtr});
+  Bld.CreateBr(MergeBB);
+
+  CGF.EmitBlock(ElseBB);
+  Bld.CreateBr(MergeBB);
+
+  CGF.EmitBlock(MergeBB);
+
+  // if (AlgoVer==1 && (LaneId >= Offset)) copy Remote Reduce list to local
+  // Reduce list.
+  auto CondCopy =
+      Bld.CreateAnd(Bld.CreateICmpEQ(AlgoVerArgVal, Bld.getInt16(1)),
+                    Bld.CreateICmpUGE(LaneIDArgVal, RemoteLaneOffsetArgVal));
+
+  llvm::BasicBlock *CpyThenBB = CGF.createBasicBlock("then");
+  llvm::BasicBlock *CpyElseBB = CGF.createBasicBlock("else");
+  llvm::BasicBlock *CpyMergeBB = CGF.createBasicBlock("ifcont");
+  Bld.CreateCondBr(CondCopy, CpyThenBB, CpyElseBB);
+
+  CGF.EmitBlock(CpyThenBB);
+  emitReductionListCopy(ThreadCopy, CGF, ReductionArrayTy, Privates,
+                        RemoteReduceList, LocalReduceList);
+  Bld.CreateBr(CpyMergeBB);
+
+  CGF.EmitBlock(CpyElseBB);
+  Bld.CreateBr(CpyMergeBB);
+
+  CGF.EmitBlock(CpyMergeBB);
+
+  CGF.FinishFunction();
+  return Fn;
+}
+
+///
+/// Design of OpenMP reductions on the GPU
+///
+/// Consider a typical OpenMP program with one or more reduction
+/// clauses:
+///
+/// float foo;
+/// double bar;
+/// #pragma omp target teams distribute parallel for \
+///             reduction(+:foo) reduction(*:bar)
+/// for (int i = 0; i < N; i++) {
+///   foo += A[i]; bar *= B[i];
+/// }
+///
+/// where 'foo' and 'bar' are reduced across all OpenMP threads in
+/// all teams.  In our OpenMP implementation on the NVPTX device an
+/// OpenMP team is mapped to a CUDA threadblock and OpenMP threads
+/// within a team are mapped to CUDA threads within a threadblock.
+/// Our goal is to efficiently aggregate values across all OpenMP
+/// threads such that:
+///
+///   - the compiler and runtime are logically concise, and
+///   - the reduction is performed efficiently in a hierarchical
+///     manner as follows: within OpenMP threads in the same warp,
+///     across warps in a threadblock, and finally across teams on
+///     the NVPTX device.
+///
+/// Introduction to Decoupling
+///
+/// We would like to decouple the compiler and the runtime so that the
+/// latter is ignorant of the reduction variables (number, data types)
+/// and the reduction operators.  This allows a simpler interface
+/// and implementation while still attaining good performance.
+///
+/// Pseudocode for the aforementioned OpenMP program generated by the
+/// compiler is as follows:
+///
+/// 1. Create private copies of reduction variables on each OpenMP
+///    thread: 'foo_private', 'bar_private'
+/// 2. Each OpenMP thread reduces the chunk of 'A' and 'B' assigned
+///    to it and writes the result in 'foo_private' and 'bar_private'
+///    respectively.
+/// 3. Call the OpenMP runtime on the GPU to reduce within a team
+///    and store the result on the team master:
+///
+///     __kmpc_nvptx_parallel_reduce_nowait(...,
+///        reduceData, shuffleReduceFn, interWarpCpyFn)
+///
+///     where:
+///       struct ReduceData {
+///         double *foo;
+///         double *bar;
+///       } reduceData
+///       reduceData.foo = &foo_private
+///       reduceData.bar = &bar_private
+///
+///     'shuffleReduceFn' and 'interWarpCpyFn' are pointers to two
+///     auxiliary functions generated by the compiler that operate on
+///     variables of type 'ReduceData'.  They aid the runtime perform
+///     algorithmic steps in a data agnostic manner.
+///
+///     'shuffleReduceFn' is a pointer to a function that reduces data
+///     of type 'ReduceData' across two OpenMP threads (lanes) in the
+///     same warp.  It takes the following arguments as input:
+///
+///     a. variable of type 'ReduceData' on the calling lane,
+///     b. its lane_id,
+///     c. an offset relative to the current lane_id to generate a
+///        remote_lane_id.  The remote lane contains the second
+///        variable of type 'ReduceData' that is to be reduced.
+///     d. an algorithm version parameter determining which reduction
+///        algorithm to use.
+///
+///     'shuffleReduceFn' retrieves data from the remote lane using
+///     efficient GPU shuffle intrinsics and reduces, using the
+///     algorithm specified by the 4th parameter, the two operands
+///     element-wise.  The result is written to the first operand.
+///
+///     Different reduction algorithms are implemented in different
+///     runtime functions, all calling 'shuffleReduceFn' to perform
+///     the essential reduction step.  Therefore, based on the 4th
+///     parameter, this function behaves slightly differently to
+///     cooperate with the runtime to ensure correctness under
+///     different circumstances.
+///
+///     'InterWarpCpyFn' is a pointer to a function that transfers
+///     reduced variables across warps.  It tunnels, through CUDA
+///     shared memory, the thread-private data of type 'ReduceData'
+///     from lane 0 of each warp to a lane in the first warp.
+/// 5. if ret == 1:
+///     The team master of the last team stores the reduced
+///     result to the globals in memory.
+///     foo += reduceData.foo; bar *= reduceData.bar
+///
+///
+/// Warp Reduction Algorithms
+///
+/// On the warp level, we have three algorithms implemented in the
+/// OpenMP runtime depending on the number of active lanes:
+///
+/// Full Warp Reduction
+///
+/// The reduce algorithm within a warp where all lanes are active
+/// is implemented in the runtime as follows:
+///
+/// full_warp_reduce(void *reduce_data,
+///                  kmp_ShuffleReductFctPtr ShuffleReduceFn) {
+///   for (int offset = WARPSIZE/2; offset > 0; offset /= 2)
+///     ShuffleReduceFn(reduce_data, 0, offset, 0);
+/// }
+///
+/// The algorithm completes in log(2, WARPSIZE) steps.
+///
+/// 'ShuffleReduceFn' is used here with lane_id set to 0 because it is
+/// not used therefore we save instructions by not retrieving lane_id
+/// from the corresponding special registers.  The 4th parameter, which
+/// represents the version of the algorithm being used, is set to 0 to
+/// signify full warp reduction.
+///
+/// In this version, 'ShuffleReduceFn' behaves, per element, as follows:
+///
+/// #reduce_elem refers to an element in the local lane's data structure
+/// #remote_elem is retrieved from a remote lane
+/// remote_elem = shuffle_down(reduce_elem, offset, WARPSIZE);
+/// reduce_elem = reduce_elem REDUCE_OP remote_elem;
+///
+/// Contiguous Partial Warp Reduction
+///
+/// This reduce algorithm is used within a warp where only the first
+/// 'n' (n <= WARPSIZE) lanes are active.  It is typically used when the
+/// number of OpenMP threads in a parallel region is not a multiple of
+/// WARPSIZE.  The algorithm is implemented in the runtime as follows:
+///
+/// void
+/// contiguous_partial_reduce(void *reduce_data,
+///                           kmp_ShuffleReductFctPtr ShuffleReduceFn,
+///                           int size, int lane_id) {
+///   int curr_size;
+///   int offset;
+///   curr_size = size;
+///   mask = curr_size/2;
+///   while (offset>0) {
+///     ShuffleReduceFn(reduce_data, lane_id, offset, 1);
+///     curr_size = (curr_size+1)/2;
+///     offset = curr_size/2;
+///   }
+/// }
+///
+/// In this version, 'ShuffleReduceFn' behaves, per element, as follows:
+///
+/// remote_elem = shuffle_down(reduce_elem, offset, WARPSIZE);
+/// if (lane_id < offset)
+///     reduce_elem = reduce_elem REDUCE_OP remote_elem
+/// else
+///     reduce_elem = remote_elem
+///
+/// This algorithm assumes that the data to be reduced are located in a
+/// contiguous subset of lanes starting from the first.  When there is
+/// an odd number of active lanes, the data in the last lane is not
+/// aggregated with any other lane's dat but is instead copied over.
+///
+/// Dispersed Partial Warp Reduction
+///
+/// This algorithm is used within a warp when any discontiguous subset of
+/// lanes are active.  It is used to implement the reduction operation
+/// across lanes in an OpenMP simd region or in a nested parallel region.
+///
+/// void
+/// dispersed_partial_reduce(void *reduce_data,
+///                          kmp_ShuffleReductFctPtr ShuffleReduceFn) {
+///   int size, remote_id;
+///   int logical_lane_id = number_of_active_lanes_before_me() * 2;
+///   do {
+///       remote_id = next_active_lane_id_right_after_me();
+///       # the above function returns 0 of no active lane
+///       # is present right after the current lane.
+///       size = number_of_active_lanes_in_this_warp();
+///       logical_lane_id /= 2;
+///       ShuffleReduceFn(reduce_data, logical_lane_id,
+///                       remote_id-1-threadIdx.x, 2);
+///   } while (logical_lane_id % 2 == 0 && size > 1);
+/// }
+///
+/// There is no assumption made about the initial state of the reduction.
+/// Any number of lanes (>=1) could be active at any position.  The reduction
+/// result is returned in the first active lane.
+///
+/// In this version, 'ShuffleReduceFn' behaves, per element, as follows:
+///
+/// remote_elem = shuffle_down(reduce_elem, offset, WARPSIZE);
+/// if (lane_id % 2 == 0 && offset > 0)
+///     reduce_elem = reduce_elem REDUCE_OP remote_elem
+/// else
+///     reduce_elem = remote_elem
+///
+///
+/// Intra-Team Reduction
+///
+/// This function, as implemented in the runtime call
+/// '__kmpc_nvptx_parallel_reduce_nowait', aggregates data across OpenMP
+/// threads in a team.  It first reduces within a warp using the
+/// aforementioned algorithms.  We then proceed to gather all such
+/// reduced values at the first warp.
+///
+/// The runtime makes use of the function 'InterWarpCpyFn', which copies
+/// data from each of the "warp master" (zeroth lane of each warp, where
+/// warp-reduced data is held) to the zeroth warp.  This step reduces (in
+/// a mathematical sense) the problem of reduction across warp masters in
+/// a block to the problem of warp reduction.
+///
+void CGOpenMPRuntimeNVPTX::emitReduction(
+    CodeGenFunction &CGF, SourceLocation Loc, ArrayRef<const Expr *> Privates,
+    ArrayRef<const Expr *> LHSExprs, ArrayRef<const Expr *> RHSExprs,
+    ArrayRef<const Expr *> ReductionOps, ReductionOptionsTy Options) {
+  if (!CGF.HaveInsertPoint())
+    return;
+
+  bool ParallelReduction = isOpenMPParallelDirective(Options.ReductionKind);
+  assert(ParallelReduction && "Invalid reduction selection in emitReduction.");
+
+  auto &C = CGM.getContext();
+
+  // 1. Build a list of reduction variables.
+  // void *RedList[<n>] = {<ReductionVars>[0], ..., <ReductionVars>[<n>-1]};
+  auto Size = RHSExprs.size();
+  for (auto *E : Privates) {
+    if (E->getType()->isVariablyModifiedType())
+      // Reserve place for array size.
+      ++Size;
+  }
+  llvm::APInt ArraySize(/*unsigned int numBits=*/32, Size);
+  QualType ReductionArrayTy =
+      C.getConstantArrayType(C.VoidPtrTy, ArraySize, ArrayType::Normal,
+                             /*IndexTypeQuals=*/0);
+  Address ReductionList =
+      CGF.CreateMemTemp(ReductionArrayTy, ".omp.reduction.red_list");
+  auto IPriv = Privates.begin();
+  unsigned Idx = 0;
+  for (unsigned I = 0, E = RHSExprs.size(); I < E; ++I, ++IPriv, ++Idx) {
+    Address Elem = CGF.Builder.CreateConstArrayGEP(ReductionList, Idx,
+                                                   CGF.getPointerSize());
+    CGF.Builder.CreateStore(
+        CGF.Builder.CreatePointerBitCastOrAddrSpaceCast(
+            CGF.EmitLValue(RHSExprs[I]).getPointer(), CGF.VoidPtrTy),
+        Elem);
+    if ((*IPriv)->getType()->isVariablyModifiedType()) {
+      // Store array size.
+      ++Idx;
+      Elem = CGF.Builder.CreateConstArrayGEP(ReductionList, Idx,
+                                             CGF.getPointerSize());
+      llvm::Value *Size = CGF.Builder.CreateIntCast(
+          CGF.getVLASize(
+                 CGF.getContext().getAsVariableArrayType((*IPriv)->getType()))
+              .first,
+          CGF.SizeTy, /*isSigned=*/false);
+      CGF.Builder.CreateStore(CGF.Builder.CreateIntToPtr(Size, CGF.VoidPtrTy),
+                              Elem);
+    }
+  }
+
+  // 2. Emit reduce_func().
+  auto *ReductionFn = emitReductionFunction(
+      CGM, CGF.ConvertTypeForMem(ReductionArrayTy)->getPointerTo(), Privates,
+      LHSExprs, RHSExprs, ReductionOps);
+
+  // 4. Build res = __kmpc_reduce{_nowait}(<gtid>, <n>, sizeof(RedList),
+  // RedList, shuffle_reduce_func, interwarp_copy_func);
+  auto *ThreadId = getThreadID(CGF, Loc);
+  auto *ReductionArrayTySize = CGF.getTypeSize(ReductionArrayTy);
+  auto *RL = CGF.Builder.CreatePointerBitCastOrAddrSpaceCast(
+      ReductionList.getPointer(), CGF.VoidPtrTy);
+
+  auto *ShuffleAndReduceFn = emitShuffleAndReduceFunction(
+      CGM, Privates, ReductionArrayTy, ReductionFn);
+  auto *InterWarpCopyFn =
+      emitInterWarpCopyFunction(CGM, Privates, ReductionArrayTy);
+
+  llvm::Value *Res = nullptr;
+  if (ParallelReduction) {
+    llvm::Value *Args[] = {ThreadId,
+                           CGF.Builder.getInt32(RHSExprs.size()),
+                           ReductionArrayTySize,
+                           RL,
+                           ShuffleAndReduceFn,
+                           InterWarpCopyFn};
+
+    Res = CGF.EmitRuntimeCall(
+        createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_parallel_reduce_nowait),
+        Args);
+  }
+
+  // 5. Build switch(res)
+  auto *DefaultBB = CGF.createBasicBlock(".omp.reduction.default");
+  auto *SwInst = CGF.Builder.CreateSwitch(Res, DefaultBB, /*NumCases=*/1);
+
+  // 6. Build case 1: where we have reduced values in the master
+  //    thread in each team.
+  //    __kmpc_end_reduce{_nowait}(<gtid>);
+  //    break;
+  auto *Case1BB = CGF.createBasicBlock(".omp.reduction.case1");
+  SwInst->addCase(CGF.Builder.getInt32(1), Case1BB);
+  CGF.EmitBlock(Case1BB);
+
+  // Add emission of __kmpc_end_reduce{_nowait}(<gtid>);
+  llvm::Value *EndArgs[] = {ThreadId};
+  auto &&CodeGen = [&Privates, &LHSExprs, &RHSExprs, &ReductionOps,
+                    this](CodeGenFunction &CGF, PrePostActionTy &Action) {
+    auto IPriv = Privates.begin();
+    auto ILHS = LHSExprs.begin();
+    auto IRHS = RHSExprs.begin();
+    for (auto *E : ReductionOps) {
+      emitSingleReductionCombiner(CGF, E, *IPriv, cast<DeclRefExpr>(*ILHS),
+                                  cast<DeclRefExpr>(*IRHS));
+      ++IPriv;
+      ++ILHS;
+      ++IRHS;
+    }
+  };
+  RegionCodeGenTy RCG(CodeGen);
+  NVPTXActionTy Action(
+      nullptr, llvm::None,
+      createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_end_reduce_nowait),
+      EndArgs);
+  RCG.setAction(Action);
+  RCG(CGF);
+  CGF.EmitBranch(DefaultBB);
+  CGF.EmitBlock(DefaultBB, /*IsFinished=*/true);
+}

cfe/trunk/lib/CodeGen/CGStmtOpenMP.cpp

for (auto IRef : C->varlists()) {
       ++IRHS;
       ++IPriv;
       ++IRed;
     }
   }
 }
 
 void CodeGenFunction::EmitOMPReductionClauseFinal(
-    const OMPExecutableDirective &D) {
+    const OMPExecutableDirective &D, const OpenMPDirectiveKind ReductionKind) {
   if (!HaveInsertPoint())
     return;
   llvm::SmallVector<const Expr *, 8> Privates;
   llvm::SmallVector<const Expr *, 8> LHSExprs;
   llvm::SmallVector<const Expr *, 8> RHSExprs;
   llvm::SmallVector<const Expr *, 8> ReductionOps;
   bool HasAtLeastOneReduction = false;
   for (const auto *C : D.getClausesOfKind<OMPReductionClause>()) {
     HasAtLeastOneReduction = true;
     Privates.append(C->privates().begin(), C->privates().end());
     LHSExprs.append(C->lhs_exprs().begin(), C->lhs_exprs().end());
     RHSExprs.append(C->rhs_exprs().begin(), C->rhs_exprs().end());
     ReductionOps.append(C->reduction_ops().begin(), C->reduction_ops().end());
   }
   if (HasAtLeastOneReduction) {
+    bool WithNowait = D.getSingleClause<OMPNowaitClause>() ||
+                      isOpenMPParallelDirective(D.getDirectiveKind()) ||
+                      D.getDirectiveKind() == OMPD_simd;
+    bool SimpleReduction = D.getDirectiveKind() == OMPD_simd;
     // Emit nowait reduction if nowait clause is present or directive is a
     // parallel directive (it always has implicit barrier).
     CGM.getOpenMPRuntime().emitReduction(
         *this, D.getLocEnd(), Privates, LHSExprs, RHSExprs, ReductionOps,
-        D.getSingleClause<OMPNowaitClause>() ||
-            isOpenMPParallelDirective(D.getDirectiveKind()) ||
-            D.getDirectiveKind() == OMPD_simd,
-        D.getDirectiveKind() == OMPD_simd);
+        {WithNowait, SimpleReduction, ReductionKind});
   }
 }
 
 static void emitPostUpdateForReductionClause(
     CodeGenFunction &CGF, const OMPExecutableDirective &D,
     const llvm::function_ref<llvm::Value *(CodeGenFunction &)> &CondGen) {
   if (!CGF.HaveInsertPoint())
     return;
if (Copyins) {
       CGF.CGM.getOpenMPRuntime().emitBarrierCall(
           CGF, S.getLocStart(), OMPD_unknown, /*EmitChecks=*/false,
           /*ForceSimpleCall=*/true);
     }
     CGF.EmitOMPPrivateClause(S, PrivateScope);
     CGF.EmitOMPReductionClauseInit(S, PrivateScope);
     (void)PrivateScope.Privatize();
     CGF.EmitStmt(cast<CapturedStmt>(S.getAssociatedStmt())->getCapturedStmt());
-    CGF.EmitOMPReductionClauseFinal(S);
+    CGF.EmitOMPReductionClauseFinal(S, /*ReductionKind=*/OMPD_parallel);
   };
   emitCommonOMPParallelDirective(*this, S, OMPD_parallel, CodeGen);
   emitPostUpdateForReductionClause(
       *this, S, [](CodeGenFunction &) -> llvm::Value * { return nullptr; });
 }
 
 void CodeGenFunction::EmitOMPLoopBody(const OMPLoopDirective &D,
                                       JumpDest LoopExit) {
CGF.EmitOMPLinearClauseInit(S);
                              CGF.EmitStopPoint(&S);
                            },
                            [](CodeGenFunction &) {});
       CGF.EmitOMPSimdFinal(
           S, [](CodeGenFunction &) -> llvm::Value * { return nullptr; });
       // Emit final copy of the lastprivate variables at the end of loops.
       if (HasLastprivateClause)
         CGF.EmitOMPLastprivateClauseFinal(S, /*NoFinals=*/true);
-      CGF.EmitOMPReductionClauseFinal(S);
+      CGF.EmitOMPReductionClauseFinal(S, /*ReductionKind=*/OMPD_simd);
       emitPostUpdateForReductionClause(
           CGF, S, [](CodeGenFunction &) -> llvm::Value * { return nullptr; });
     }
     CGF.EmitOMPLinearClauseFinal(
         S, [](CodeGenFunction &) -> llvm::Value * { return nullptr; });
     // Emit: if (PreCond) - end.
     if (ContBlock) {
       CGF.EmitBranch(ContBlock);
// Emit 'then' code.
       }
       if (isOpenMPSimdDirective(S.getDirectiveKind())) {
         EmitOMPSimdFinal(S,
                          [&](CodeGenFunction &CGF) -> llvm::Value * {
                            return CGF.Builder.CreateIsNotNull(
                                CGF.EmitLoadOfScalar(IL, S.getLocStart()));
                          });
       }
-      EmitOMPReductionClauseFinal(S);
+      EmitOMPReductionClauseFinal(
+          S, /*ReductionKind=*/isOpenMPSimdDirective(S.getDirectiveKind())
+                 ? /*Parallel and Simd*/ OMPD_parallel_for_simd
+                 : /*Parallel only*/ OMPD_parallel);
       // Emit post-update of the reduction variables if IsLastIter != 0.
       emitPostUpdateForReductionClause(
           *this, S, [&](CodeGenFunction &CGF) -> llvm::Value * {
             return CGF.Builder.CreateIsNotNull(
                 CGF.EmitLoadOfScalar(IL, S.getLocStart()));
           });
       // Emit final copy of the lastprivate variables if IsLastIter != 0.
       if (HasLastprivateClause)
auto &&CodeGen = [&S, Stmt, CS, &HasLastprivates](CodeGenFunction &CGF,
     // while (idx <= UB) { BODY; ++idx; }
     CGF.EmitOMPInnerLoop(S, /*RequiresCleanup=*/false, &Cond, &Inc, BodyGen,
                          [](CodeGenFunction &) {});
     // Tell the runtime we are done.
     auto &&CodeGen = [&S](CodeGenFunction &CGF) {
       CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, S.getLocEnd());
     };
     CGF.OMPCancelStack.emitExit(CGF, S.getDirectiveKind(), CodeGen);
-    CGF.EmitOMPReductionClauseFinal(S);
+    CGF.EmitOMPReductionClauseFinal(S, /*ReductionKind=*/OMPD_parallel);
     // Emit post-update of the reduction variables if IsLastIter != 0.
     emitPostUpdateForReductionClause(
         CGF, S, [&](CodeGenFunction &CGF) -> llvm::Value * {
           return CGF.Builder.CreateIsNotNull(
               CGF.EmitLoadOfScalar(IL, S.getLocStart()));
         });
 
     // Emit final copy of the lastprivate variables if IsLastIter != 0.

 }
 
 static void emitTargetParallelRegion(CodeGenFunction &CGF,
                                      const OMPTargetParallelDirective &S,
                                      PrePostActionTy &Action) {
   // Get the captured statement associated with the 'parallel' region.
   auto *CS = S.getCapturedStmt(OMPD_parallel);
   Action.Enter(CGF);
-  auto &&CodeGen = [CS](CodeGenFunction &CGF, PrePostActionTy &) {
+  auto &&CodeGen = [&S, CS](CodeGenFunction &CGF, PrePostActionTy &) {
+    CodeGenFunction::OMPPrivateScope PrivateScope(CGF);
+    (void)CGF.EmitOMPFirstprivateClause(S, PrivateScope);
+    CGF.EmitOMPPrivateClause(S, PrivateScope);
+    CGF.EmitOMPReductionClauseInit(S, PrivateScope);
+    (void)PrivateScope.Privatize();
     // TODO: Add support for clauses.
     CGF.EmitStmt(CS->getCapturedStmt());
+    CGF.EmitOMPReductionClauseFinal(S, /*ReductionKind=*/OMPD_parallel);
   };
   emitCommonOMPParallelDirective(CGF, S, OMPD_parallel, CodeGen);
+  emitPostUpdateForReductionClause(
+      CGF, S, [](CodeGenFunction &) -> llvm::Value * { return nullptr; });
 }
 
 void CodeGenFunction::EmitOMPTargetParallelDeviceFunction(
     CodeGenModule &CGM, StringRef ParentName,
     const OMPTargetParallelDirective &S) {
   auto &&CodeGen = [&S](CodeGenFunction &CGF, PrePostActionTy &Action) {
     emitTargetParallelRegion(CGF, S, Action);
   };

cfe/trunk/lib/CodeGen/CodeGenFunction.h

#endif
   /// proper codegen in internal captured statement.
   ///
   void EmitOMPReductionClauseInit(const OMPExecutableDirective &D,
                                   OMPPrivateScope &PrivateScope);
   /// \brief Emit final update of reduction values to original variables at
   /// the end of the directive.
   ///
   /// \param D Directive that has at least one 'reduction' directives.
-  void EmitOMPReductionClauseFinal(const OMPExecutableDirective &D);
+  /// \param ReductionKind The kind of reduction to perform.
+  void EmitOMPReductionClauseFinal(const OMPExecutableDirective &D,
+                                   const OpenMPDirectiveKind ReductionKind);
   /// \brief Emit initial code for linear variables. Creates private copies
   /// and initializes them with the values according to OpenMP standard.
   ///
   /// \param D Directive (possibly) with the 'linear' clause.
   void EmitOMPLinearClauseInit(const OMPLoopDirective &D);
 
   typedef const llvm::function_ref<void(CodeGenFunction & /*CGF*/,
                                         llvm::Value * /*OutlinedFn*/,

cfe/trunk/test/OpenMP/nvptx_target_parallel_reduction_codegen.cpp

+// Test target codegen - host bc file has to be created first.
+// RUN: %clang_cc1 -verify -fopenmp -x c++ -triple powerpc64le-unknown-unknown -fopenmp-targets=nvptx64-nvidia-cuda -emit-llvm-bc %s -o %t-ppc-host.bc
+// RUN: %clang_cc1 -verify -fopenmp -x c++ -triple nvptx64-unknown-unknown -fopenmp-targets=nvptx64-nvidia-cuda -emit-llvm %s -fopenmp-is-device -fopenmp-host-ir-file-path %t-ppc-host.bc -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-64
+// RUN: %clang_cc1 -verify -fopenmp -x c++ -triple i386-unknown-unknown -fopenmp-targets=nvptx-nvidia-cuda -emit-llvm-bc %s -o %t-x86-host.bc
+// RUN: %clang_cc1 -verify -fopenmp -x c++ -triple nvptx-unknown-unknown -fopenmp-targets=nvptx-nvidia-cuda -emit-llvm %s -fopenmp-is-device -fopenmp-host-ir-file-path %t-x86-host.bc -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-32
+// RUN: %clang_cc1 -verify -fopenmp -fexceptions -fcxx-exceptions -x c++ -triple nvptx-unknown-unknown -fopenmp-targets=nvptx-nvidia-cuda -emit-llvm %s -fopenmp-is-device -fopenmp-host-ir-file-path %t-x86-host.bc -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-32
+// expected-no-diagnostics
+#ifndef HEADER
+#define HEADER
+
+// Check for the data transfer medium in shared memory to transfer the reduction list to the first warp.
+// CHECK-DAG: [[TRANSFER_STORAGE:@.+]] = common addrspace([[SHARED_ADDRSPACE:[0-9]+]]) global [32 x i64]
+
+// Check that the execution mode of all 3 target regions is set to Spmd Mode.
+// CHECK-DAG: {{@__omp_offloading_.+l27}}_exec_mode = weak constant i8 0
+// CHECK-DAG: {{@__omp_offloading_.+l32}}_exec_mode = weak constant i8 0
+// CHECK-DAG: {{@__omp_offloading_.+l38}}_exec_mode = weak constant i8 0
+
+template<typename tx>
+tx ftemplate(int n) {
+  int a;
+  short b;
+  tx c;
+  float d;
+  double e;
+
+  #pragma omp target parallel reduction(+: e) map(tofrom: e)
+  {
+    e += 5;
+  }
+
+  #pragma omp target parallel reduction(^: c) reduction(*: d) map(tofrom: c,d)
+  {
+    c ^= 2;
+    d *= 33;
+  }
+
+  #pragma omp target parallel reduction(|: a) reduction(max: b) map(tofrom: a,b)
+  {
+    a |= 1;
+    b = 99 > b ? 99 : b;
+  }
+
+  return a+b+c+d+e;
+}
+
+int bar(int n){
+  int a = 0;
+
+  a += ftemplate<char>(n);
+
+  return a;
+}
+
+  // CHECK: define {{.*}}void {{@__omp_offloading_.+template.+l27}}(
+  //
+  // CHECK: call void @__kmpc_spmd_kernel_init(
+  // CHECK: br label {{%?}}[[EXECUTE:.+]]
+  //
+  // CHECK: [[EXECUTE]]
+  // CHECK: {{call|invoke}} void [[PFN:@.+]](i32*
+  // CHECK: call void @__kmpc_spmd_kernel_deinit()
+  //
+  //
+  // define internal void [[PFN]](
+  // CHECK: store double {{[0\.e\+]+}}, double* [[E:%.+]], align
+  // CHECK: [[EV:%.+]] = load double, double* [[E]], align
+  // CHECK: [[ADD:%.+]] = fadd double [[EV]], 5
+  // CHECK: store double [[ADD]], double* [[E]], align
+  // CHECK: [[PTR1:%.+]] = getelementptr inbounds [[RLT:.+]], [1 x i8*]* [[RL:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[E_CAST:%.+]] = bitcast double* [[E]] to i8*
+  // CHECK: store i8* [[E_CAST]], i8** [[PTR1]], align
+  // CHECK: [[ARG_RL:%.+]] = bitcast [[RLT]]* [[RL]] to i8*
+  // CHECK: [[RET:%.+]] = call i32 @__kmpc_nvptx_parallel_reduce_nowait(i32 {{.+}}, i32 1, i{{32|64}} {{4|8}}, i8* [[ARG_RL]], void (i8*, i16, i16, i16)* [[SHUFFLE_REDUCE_FN:@.+]], void (i8*, i32)* [[WARP_COPY_FN:@.+]])
+  // CHECK: switch i32 [[RET]], label {{%?}}[[DEFAULTLABEL:.+]] [
+  // CHECK: i32 1, label {{%?}}[[REDLABEL:.+]]
+
+  // CHECK: [[REDLABEL]]
+  // CHECK: [[E_INV:%.+]] = load double, double* [[E_IN:%.+]], align
+  // CHECK: [[EV:%.+]] = load double, double* [[E]], align
+  // CHECK: [[ADD:%.+]] = fadd double [[E_INV]], [[EV]]
+  // CHECK: store double [[ADD]], double* [[E_IN]], align
+  // CHECK: call void @__kmpc_nvptx_end_reduce_nowait(
+  // CHECK: br label %[[DEFAULTLABEL]]
+  //
+  // CHECK: [[DEFAULTLABEL]]
+  // CHECK: ret
+
+  //
+  // Reduction function
+  // CHECK: define internal void [[REDUCTION_FUNC:@.+]](i8*, i8*)
+  // CHECK: [[VAR_RHS_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST_RHS:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[VAR_RHS_VOID:%.+]] = load i8*, i8** [[VAR_RHS_REF]],
+  // CHECK: [[VAR_RHS:%.+]] = bitcast i8* [[VAR_RHS_VOID]] to double*
+  //
+  // CHECK: [[VAR_LHS_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST_LHS:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[VAR_LHS_VOID:%.+]] = load i8*, i8** [[VAR_LHS_REF]],
+  // CHECK: [[VAR_LHS:%.+]] = bitcast i8* [[VAR_LHS_VOID]] to double*
+  //
+  // CHECK: [[VAR_LHS_VAL:%.+]] = load double, double* [[VAR_LHS]],
+  // CHECK: [[VAR_RHS_VAL:%.+]] = load double, double* [[VAR_RHS]],
+  // CHECK: [[RES:%.+]] = fadd double [[VAR_LHS_VAL]], [[VAR_RHS_VAL]]
+  // CHECK: store double [[RES]], double* [[VAR_LHS]],
+  // CHECK: ret void
+
+  //
+  // Shuffle and reduce function
+  // CHECK: define internal void [[SHUFFLE_REDUCE_FN]](i8*, i16 {{.*}}, i16 {{.*}}, i16 {{.*}})
+  // CHECK: [[REMOTE_RED_LIST:%.+]] = alloca [[RLT]], align
+  // CHECK: [[REMOTE_ELT:%.+]] = alloca double
+  //
+  // CHECK: [[LANEID:%.+]] = load i16, i16* {{.+}}, align
+  // CHECK: [[LANEOFFSET:%.+]] = load i16, i16* {{.+}}, align
+  // CHECK: [[ALGVER:%.+]] = load i16, i16* {{.+}}, align
+  //
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[REMOTE_ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[REMOTE_RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to double*
+  // CHECK: [[ELT_VAL:%.+]] = load double, double* [[ELT]], align
+  //
+  // CHECK: [[ELT_CAST:%.+]] = bitcast double [[ELT_VAL]] to i64
+  // CHECK: [[WS32:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+  // CHECK: [[WS:%.+]] = trunc i32 [[WS32]] to i16
+  // CHECK: [[REMOTE_ELT_VAL64:%.+]] = call i64 @__kmpc_shuffle_int64(i64 [[ELT_CAST]], i16 [[LANEOFFSET]], i16 [[WS]])
+  // CHECK: [[REMOTE_ELT_VAL:%.+]] = bitcast i64 [[REMOTE_ELT_VAL64]] to double
+  //
+  // CHECK: store double [[REMOTE_ELT_VAL]], double* [[REMOTE_ELT]], align
+  // CHECK: [[REMOTE_ELT_VOID:%.+]] = bitcast double* [[REMOTE_ELT]] to i8*
+  // CHECK: store i8* [[REMOTE_ELT_VOID]], i8** [[REMOTE_ELT_REF]], align
+  //
+  // Condition to reduce
+  // CHECK: [[CONDALG0:%.+]] = icmp eq i16 [[ALGVER]], 0
+  //
+  // CHECK: [[COND1:%.+]] = icmp eq i16 [[ALGVER]], 1
+  // CHECK: [[COND2:%.+]] = icmp ult i16 [[LANEID]], [[LANEOFFSET]]
+  // CHECK: [[CONDALG1:%.+]] = and i1 [[COND1]], [[COND2]]
+  //
+  // CHECK: [[COND3:%.+]] = icmp eq i16 [[ALGVER]], 2
+  // CHECK: [[COND4:%.+]] = and i16 [[LANEID]], 1
+  // CHECK: [[COND5:%.+]] = icmp eq i16 [[COND4]], 0
+  // CHECK: [[COND6:%.+]] = and i1 [[COND3]], [[COND5]]
+  // CHECK: [[COND7:%.+]] = icmp sgt i16 [[LANEOFFSET]], 0
+  // CHECK: [[CONDALG2:%.+]] = and i1 [[COND6]], [[COND7]]
+  //
+  // CHECK: [[COND8:%.+]] = or i1 [[CONDALG0]], [[CONDALG1]]
+  // CHECK: [[SHOULD_REDUCE:%.+]] = or i1 [[COND8]], [[CONDALG2]]
+  // CHECK: br i1 [[SHOULD_REDUCE]], label {{%?}}[[DO_REDUCE:.+]], label {{%?}}[[REDUCE_ELSE:.+]]
+  //
+  // CHECK: [[DO_REDUCE]]
+  // CHECK: [[RED_LIST1_VOID:%.+]] = bitcast [[RLT]]* [[RED_LIST]] to i8*
+  // CHECK: [[RED_LIST2_VOID:%.+]] = bitcast [[RLT]]* [[REMOTE_RED_LIST]] to i8*
+  // CHECK: call void [[REDUCTION_FUNC]](i8* [[RED_LIST1_VOID]], i8* [[RED_LIST2_VOID]])
+  // CHECK: br label {{%?}}[[REDUCE_CONT:.+]]
+  //
+  // CHECK: [[REDUCE_ELSE]]
+  // CHECK: br label {{%?}}[[REDUCE_CONT]]
+  //
+  // CHECK: [[REDUCE_CONT]]
+  // Now check if we should just copy over the remote reduction list
+  // CHECK: [[COND1:%.+]] = icmp eq i16 [[ALGVER]], 1
+  // CHECK: [[COND2:%.+]] = icmp uge i16 [[LANEID]], [[LANEOFFSET]]
+  // CHECK: [[SHOULD_COPY:%.+]] = and i1 [[COND1]], [[COND2]]
+  // CHECK: br i1 [[SHOULD_COPY]], label {{%?}}[[DO_COPY:.+]], label {{%?}}[[COPY_ELSE:.+]]
+  //
+  // CHECK: [[DO_COPY]]
+  // CHECK: [[REMOTE_ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[REMOTE_RED_LIST]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[REMOTE_ELT_VOID:%.+]] = load i8*, i8** [[REMOTE_ELT_REF]],
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to double*
+  // CHECK: [[REMOTE_ELT:%.+]] = bitcast i8* [[REMOTE_ELT_VOID]] to double*
+  // CHECK: [[REMOTE_ELT_VAL:%.+]] = load double, double* [[REMOTE_ELT]], align
+  // CHECK: store double [[REMOTE_ELT_VAL]], double* [[ELT]], align
+  // CHECK: br label {{%?}}[[COPY_CONT:.+]]
+  //
+  // CHECK: [[COPY_ELSE]]
+  // CHECK: br label {{%?}}[[COPY_CONT]]
+  //
+  // CHECK: [[COPY_CONT]]
+  // CHECK: void
+
+  //
+  // Inter warp copy function
+  // CHECK: define internal void [[WARP_COPY_FN]](i8*, i32)
+  // CHECK-DAG: [[LANEID:%.+]] = and i32 {{.+}}, 31
+  // CHECK-DAG: [[WARPID:%.+]] = ashr i32 {{.+}}, 5
+  // CHECK-DAG: [[RED_LIST:%.+]] = bitcast i8* {{.+}} to [[RLT]]*
+  // CHECK: [[IS_WARP_MASTER:%.+]] = icmp eq i32 [[LANEID]], 0
+  // CHECK: br i1 [[IS_WARP_MASTER]], label {{%?}}[[DO_COPY:.+]], label {{%?}}[[COPY_ELSE:.+]]
+  //
+  // [[DO_COPY]]
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to double*
+  // CHECK: [[ELT_VAL:%.+]] = load double, double* [[ELT]], align
+  //
+  // CHECK: [[MEDIUM_ELT64:%.+]] = getelementptr inbounds [32 x i64], [32 x i64] addrspace([[SHARED_ADDRSPACE]])* [[TRANSFER_STORAGE]], i64 0, i32 [[WARPID]]
+  // CHECK: [[MEDIUM_ELT:%.+]] = bitcast i64 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT64]] to double addrspace([[SHARED_ADDRSPACE]])*
+  // CHECK: store double [[ELT_VAL]], double addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT]], align
+  // CHECK: br label {{%?}}[[COPY_CONT:.+]]
+  //
+  // CHECK: [[COPY_ELSE]]
+  // CHECK: br label {{%?}}[[COPY_CONT]]
+  //
+  // Barrier after copy to shared memory storage medium.
+  // CHECK: [[COPY_CONT]]
+  // CHECK: [[WS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+  // CHECK: [[ACTIVE_THREADS:%.+]] = mul nsw i32 [[ACTIVE_WARPS:%.+]], [[WS]]
+  // CHECK: call void @llvm.nvvm.barrier(i32 1, i32 [[ACTIVE_THREADS]])
+  //
+  // Read into warp 0.
+  // CHECK: [[IS_W0_ACTIVE_THREAD:%.+]] = icmp ult i32 [[TID:%.+]], [[ACTIVE_WARPS]]
+  // CHECK: br i1 [[IS_W0_ACTIVE_THREAD]], label {{%?}}[[DO_READ:.+]], label {{%?}}[[READ_ELSE:.+]]
+  //
+  // CHECK: [[DO_READ]]
+  // CHECK: [[MEDIUM_ELT64:%.+]] = getelementptr inbounds [32 x i64], [32 x i64] addrspace([[SHARED_ADDRSPACE]])* [[TRANSFER_STORAGE]], i64 0, i32 [[TID]]
+  // CHECK: [[MEDIUM_ELT:%.+]] = bitcast i64 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT64]] to double addrspace([[SHARED_ADDRSPACE]])*
+  // CHECK: [[MEDIUM_ELT_VAL:%.+]] = load double, double addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT]], align
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to double*
+  // CHECK: store double [[MEDIUM_ELT_VAL]], double* [[ELT]], align
+  // CHECK: br label {{%?}}[[READ_CONT:.+]]
+  //
+  // CHECK: [[READ_ELSE]]
+  // CHECK: br label {{%?}}[[READ_CONT]]
+  //
+  // CHECK: [[READ_CONT]]
+  // CHECK: call void @llvm.nvvm.barrier(i32 1, i32 [[ACTIVE_THREADS]])
+  // CHECK: ret
+
+
+
+
+
+
+
+
+
+
+  // CHECK: define {{.*}}void {{@__omp_offloading_.+template.+l32}}(
+  //
+  // CHECK: call void @__kmpc_spmd_kernel_init(
+  // CHECK: br label {{%?}}[[EXECUTE:.+]]
+  //
+  // CHECK: [[EXECUTE]]
+  // CHECK: {{call|invoke}} void [[PFN1:@.+]](i32*
+  // CHECK: call void @__kmpc_spmd_kernel_deinit()
+  //
+  //
+  // define internal void [[PFN1]](
+  // CHECK: store float {{1\.[0e\+]+}}, float* [[D:%.+]], align
+  // CHECK: [[C_VAL:%.+]] = load i8, i8* [[C:%.+]], align
+  // CHECK: [[CONV:%.+]] = sext i8 [[C_VAL]] to i32
+  // CHECK: [[XOR:%.+]] = xor i32 [[CONV]], 2
+  // CHECK: [[TRUNC:%.+]] = trunc i32 [[XOR]] to i8
+  // CHECK: store i8 [[TRUNC]], i8* [[C]], align
+  // CHECK: [[DV:%.+]] = load float, float* [[D]], align
+  // CHECK: [[MUL:%.+]] = fmul float [[DV]], {{[0-9e\.\+]+}}
+  // CHECK: store float [[MUL]], float* [[D]], align
+  // CHECK: [[PTR1:%.+]] = getelementptr inbounds [[RLT:.+]], [2 x i8*]* [[RL:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: store i8* [[C]], i8** [[PTR1]], align
+  // CHECK: [[PTR2:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RL]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[D_CAST:%.+]] = bitcast float* [[D]] to i8*
+  // CHECK: store i8* [[D_CAST]], i8** [[PTR2]], align
+  // CHECK: [[ARG_RL:%.+]] = bitcast [[RLT]]* [[RL]] to i8*
+  // CHECK: [[RET:%.+]] = call i32 @__kmpc_nvptx_parallel_reduce_nowait(i32 {{.+}}, i32 2, i{{32|64}} {{8|16}}, i8* [[ARG_RL]], void (i8*, i16, i16, i16)* [[SHUFFLE_REDUCE_FN:@.+]], void (i8*, i32)* [[WARP_COPY_FN:@.+]])
+  // CHECK: switch i32 [[RET]], label {{%?}}[[DEFAULTLABEL:.+]] [
+  // CHECK: i32 1, label {{%?}}[[REDLABEL:.+]]
+
+  // CHECK: [[REDLABEL]]
+  // CHECK: [[C_INV8:%.+]] = load i8, i8* [[C_IN:%.+]], align
+  // CHECK: [[C_INV:%.+]] = sext i8 [[C_INV8]] to i32
+  // CHECK: [[CV8:%.+]] = load i8, i8* [[C]], align
+  // CHECK: [[CV:%.+]] = sext i8 [[CV8]] to i32
+  // CHECK: [[XOR:%.+]] = xor i32 [[C_INV]], [[CV]]
+  // CHECK: [[TRUNC:%.+]] = trunc i32 [[XOR]] to i8
+  // CHECK: store i8 [[TRUNC]], i8* [[C_IN]], align
+  // CHECK: [[D_INV:%.+]] = load float, float* [[D_IN:%.+]], align
+  // CHECK: [[DV:%.+]] = load float, float* [[D]], align
+  // CHECK: [[MUL:%.+]] = fmul float [[D_INV]], [[DV]]
+  // CHECK: store float [[MUL]], float* [[D_IN]], align
+  // CHECK: call void @__kmpc_nvptx_end_reduce_nowait(
+  // CHECK: br label %[[DEFAULTLABEL]]
+  //
+  // CHECK: [[DEFAULTLABEL]]
+  // CHECK: ret
+
+  //
+  // Reduction function
+  // CHECK: define internal void [[REDUCTION_FUNC:@.+]](i8*, i8*)
+  // CHECK: [[VAR1_RHS_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST_RHS:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[VAR1_RHS:%.+]] = load i8*, i8** [[VAR1_RHS_REF]],
+  //
+  // CHECK: [[VAR1_LHS_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST_LHS:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[VAR1_LHS:%.+]] = load i8*, i8** [[VAR1_LHS_REF]],
+  //
+  // CHECK: [[VAR2_RHS_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST_RHS]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[VAR2_RHS_VOID:%.+]] = load i8*, i8** [[VAR2_RHS_REF]],
+  // CHECK: [[VAR2_RHS:%.+]] = bitcast i8* [[VAR2_RHS_VOID]] to float*
+  //
+  // CHECK: [[VAR2_LHS_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST_LHS]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[VAR2_LHS_VOID:%.+]] = load i8*, i8** [[VAR2_LHS_REF]],
+  // CHECK: [[VAR2_LHS:%.+]] = bitcast i8* [[VAR2_LHS_VOID]] to float*
+  //
+  // CHECK: [[VAR1_LHS_VAL8:%.+]] = load i8, i8* [[VAR1_LHS]],
+  // CHECK: [[VAR1_LHS_VAL:%.+]] = sext i8 [[VAR1_LHS_VAL8]] to i32
+  // CHECK: [[VAR1_RHS_VAL8:%.+]] = load i8, i8* [[VAR1_RHS]],
+  // CHECK: [[VAR1_RHS_VAL:%.+]] = sext i8 [[VAR1_RHS_VAL8]] to i32
+  // CHECK: [[XOR:%.+]] = xor i32 [[VAR1_LHS_VAL]], [[VAR1_RHS_VAL]]
+  // CHECK: [[RES:%.+]] = trunc i32 [[XOR]] to i8
+  // CHECK: store i8 [[RES]], i8* [[VAR1_LHS]],
+  //
+  // CHECK: [[VAR2_LHS_VAL:%.+]] = load float, float* [[VAR2_LHS]],
+  // CHECK: [[VAR2_RHS_VAL:%.+]] = load float, float* [[VAR2_RHS]],
+  // CHECK: [[RES:%.+]] = fmul float [[VAR2_LHS_VAL]], [[VAR2_RHS_VAL]]
+  // CHECK: store float [[RES]], float* [[VAR2_LHS]],
+  // CHECK: ret void
+
+  //
+  // Shuffle and reduce function
+  // CHECK: define internal void [[SHUFFLE_REDUCE_FN]](i8*, i16 {{.*}}, i16 {{.*}}, i16 {{.*}})
+  // CHECK: [[REMOTE_RED_LIST:%.+]] = alloca [[RLT]], align
+  // CHECK: [[REMOTE_ELT1:%.+]] = alloca i8
+  // CHECK: [[REMOTE_ELT2:%.+]] = alloca float
+  //
+  // CHECK: [[LANEID:%.+]] = load i16, i16* {{.+}}, align
+  // CHECK: [[LANEOFFSET:%.+]] = load i16, i16* {{.+}}, align
+  // CHECK: [[ALGVER:%.+]] = load i16, i16* {{.+}}, align
+  //
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[REMOTE_ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[REMOTE_RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VAL:%.+]] = load i8, i8* [[ELT_VOID]], align
+  //
+  // CHECK: [[ELT_CAST:%.+]] = sext i8 [[ELT_VAL]] to i32
+  // CHECK: [[WS32:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+  // CHECK: [[WS:%.+]] = trunc i32 [[WS32]] to i16
+  // CHECK: [[REMOTE_ELT1_VAL32:%.+]] = call i32 @__kmpc_shuffle_int32(i32 [[ELT_CAST]], i16 [[LANEOFFSET]], i16 [[WS]])
+  // CHECK: [[REMOTE_ELT1_VAL:%.+]] = trunc i32 [[REMOTE_ELT1_VAL32]] to i8
+  //
+  // CHECK: store i8 [[REMOTE_ELT1_VAL]], i8* [[REMOTE_ELT1]], align
+  // CHECK: store i8* [[REMOTE_ELT1]], i8** [[REMOTE_ELT_REF]], align
+  //
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[REMOTE_ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[REMOTE_RED_LIST]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to float*
+  // CHECK: [[ELT_VAL:%.+]] = load float, float* [[ELT]], align
+  //
+  // CHECK: [[ELT_CAST:%.+]] = bitcast float [[ELT_VAL]] to i32
+  // CHECK: [[WS32:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+  // CHECK: [[WS:%.+]] = trunc i32 [[WS32]] to i16
+  // CHECK: [[REMOTE_ELT2_VAL32:%.+]] = call i32 @__kmpc_shuffle_int32(i32 [[ELT_CAST]], i16 [[LANEOFFSET]], i16 [[WS]])
+  // CHECK: [[REMOTE_ELT2_VAL:%.+]] = bitcast i32 [[REMOTE_ELT2_VAL32]] to float
+  //
+  // CHECK: store float [[REMOTE_ELT2_VAL]], float* [[REMOTE_ELT2]], align
+  // CHECK: [[REMOTE_ELT2C:%.+]] = bitcast float* [[REMOTE_ELT2]] to i8*
+  // CHECK: store i8* [[REMOTE_ELT2C]], i8** [[REMOTE_ELT_REF]], align
+  //
+  // Condition to reduce
+  // CHECK: [[CONDALG0:%.+]] = icmp eq i16 [[ALGVER]], 0
+  //
+  // CHECK: [[COND1:%.+]] = icmp eq i16 [[ALGVER]], 1
+  // CHECK: [[COND2:%.+]] = icmp ult i16 [[LANEID]], [[LANEOFFSET]]
+  // CHECK: [[CONDALG1:%.+]] = and i1 [[COND1]], [[COND2]]
+  //
+  // CHECK: [[COND3:%.+]] = icmp eq i16 [[ALGVER]], 2
+  // CHECK: [[COND4:%.+]] = and i16 [[LANEID]], 1
+  // CHECK: [[COND5:%.+]] = icmp eq i16 [[COND4]], 0
+  // CHECK: [[COND6:%.+]] = and i1 [[COND3]], [[COND5]]
+  // CHECK: [[COND7:%.+]] = icmp sgt i16 [[LANEOFFSET]], 0
+  // CHECK: [[CONDALG2:%.+]] = and i1 [[COND6]], [[COND7]]
+  //
+  // CHECK: [[COND8:%.+]] = or i1 [[CONDALG0]], [[CONDALG1]]
+  // CHECK: [[SHOULD_REDUCE:%.+]] = or i1 [[COND8]], [[CONDALG2]]
+  // CHECK: br i1 [[SHOULD_REDUCE]], label {{%?}}[[DO_REDUCE:.+]], label {{%?}}[[REDUCE_ELSE:.+]]
+  //
+  // CHECK: [[DO_REDUCE]]
+  // CHECK: [[RED_LIST1_VOID:%.+]] = bitcast [[RLT]]* [[RED_LIST]] to i8*
+  // CHECK: [[RED_LIST2_VOID:%.+]] = bitcast [[RLT]]* [[REMOTE_RED_LIST]] to i8*
+  // CHECK: call void [[REDUCTION_FUNC]](i8* [[RED_LIST1_VOID]], i8* [[RED_LIST2_VOID]])
+  // CHECK: br label {{%?}}[[REDUCE_CONT:.+]]
+  //
+  // CHECK: [[REDUCE_ELSE]]
+  // CHECK: br label {{%?}}[[REDUCE_CONT]]
+  //
+  // CHECK: [[REDUCE_CONT]]
+  // Now check if we should just copy over the remote reduction list
+  // CHECK: [[COND1:%.+]] = icmp eq i16 [[ALGVER]], 1
+  // CHECK: [[COND2:%.+]] = icmp uge i16 [[LANEID]], [[LANEOFFSET]]
+  // CHECK: [[SHOULD_COPY:%.+]] = and i1 [[COND1]], [[COND2]]
+  // CHECK: br i1 [[SHOULD_COPY]], label {{%?}}[[DO_COPY:.+]], label {{%?}}[[COPY_ELSE:.+]]
+  //
+  // CHECK: [[DO_COPY]]
+  // CHECK: [[REMOTE_ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[REMOTE_RED_LIST]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[REMOTE_ELT_VOID:%.+]] = load i8*, i8** [[REMOTE_ELT_REF]],
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[REMOTE_ELT_VAL:%.+]] = load i8, i8* [[REMOTE_ELT_VOID]], align
+  // CHECK: store i8 [[REMOTE_ELT_VAL]], i8* [[ELT_VOID]], align
+  //
+  // CHECK: [[REMOTE_ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[REMOTE_RED_LIST]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[REMOTE_ELT_VOID:%.+]] = load i8*, i8** [[REMOTE_ELT_REF]],
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to float*
+  // CHECK: [[REMOTE_ELT:%.+]] = bitcast i8* [[REMOTE_ELT_VOID]] to float*
+  // CHECK: [[REMOTE_ELT_VAL:%.+]] = load float, float* [[REMOTE_ELT]], align
+  // CHECK: store float [[REMOTE_ELT_VAL]], float* [[ELT]], align
+  // CHECK: br label {{%?}}[[COPY_CONT:.+]]
+  //
+  // CHECK: [[COPY_ELSE]]
+  // CHECK: br label {{%?}}[[COPY_CONT]]
+  //
+  // CHECK: [[COPY_CONT]]
+  // CHECK: void
+
+  //
+  // Inter warp copy function
+  // CHECK: define internal void [[WARP_COPY_FN]](i8*, i32)
+  // CHECK-DAG: [[LANEID:%.+]] = and i32 {{.+}}, 31
+  // CHECK-DAG: [[WARPID:%.+]] = ashr i32 {{.+}}, 5
+  // CHECK-DAG: [[RED_LIST:%.+]] = bitcast i8* {{.+}} to [[RLT]]*
+  // CHECK: [[IS_WARP_MASTER:%.+]] = icmp eq i32 [[LANEID]], 0
+  // CHECK: br i1 [[IS_WARP_MASTER]], label {{%?}}[[DO_COPY:.+]], label {{%?}}[[COPY_ELSE:.+]]
+  //
+  // [[DO_COPY]]
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT_VAL:%.+]] = load i8, i8* [[ELT_VOID]], align
+  //
+  // CHECK: [[MEDIUM_ELT64:%.+]] = getelementptr inbounds [32 x i64], [32 x i64] addrspace([[SHARED_ADDRSPACE]])* [[TRANSFER_STORAGE]], i64 0, i32 [[WARPID]]
+  // CHECK: [[MEDIUM_ELT:%.+]] = bitcast i64 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT64]] to i8 addrspace([[SHARED_ADDRSPACE]])*
+  // CHECK: store i8 [[ELT_VAL]], i8 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT]], align
+  // CHECK: br label {{%?}}[[COPY_CONT:.+]]
+  //
+  // CHECK: [[COPY_ELSE]]
+  // CHECK: br label {{%?}}[[COPY_CONT]]
+  //
+  // Barrier after copy to shared memory storage medium.
+  // CHECK: [[COPY_CONT]]
+  // CHECK: [[WS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+  // CHECK: [[ACTIVE_THREADS:%.+]] = mul nsw i32 [[ACTIVE_WARPS:%.+]], [[WS]]
+  // CHECK: call void @llvm.nvvm.barrier(i32 1, i32 [[ACTIVE_THREADS]])
+  //
+  // Read into warp 0.
+  // CHECK: [[IS_W0_ACTIVE_THREAD:%.+]] = icmp ult i32 [[TID:%.+]], [[ACTIVE_WARPS]]
+  // CHECK: br i1 [[IS_W0_ACTIVE_THREAD]], label {{%?}}[[DO_READ:.+]], label {{%?}}[[READ_ELSE:.+]]
+  //
+  // CHECK: [[DO_READ]]
+  // CHECK: [[MEDIUM_ELT64:%.+]] = getelementptr inbounds [32 x i64], [32 x i64] addrspace([[SHARED_ADDRSPACE]])* [[TRANSFER_STORAGE]], i64 0, i32 [[TID]]
+  // CHECK: [[MEDIUM_ELT:%.+]] = bitcast i64 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT64]] to i8 addrspace([[SHARED_ADDRSPACE]])*
+  // CHECK: [[MEDIUM_ELT_VAL:%.+]] = load i8, i8 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT]], align
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: store i8 [[MEDIUM_ELT_VAL]], i8* [[ELT_VOID]], align
+  // CHECK: br label {{%?}}[[READ_CONT:.+]]
+  //
+  // CHECK: [[READ_ELSE]]
+  // CHECK: br label {{%?}}[[READ_CONT]]
+  //
+  // CHECK: [[READ_CONT]]
+  // CHECK: call void @llvm.nvvm.barrier(i32 1, i32 [[ACTIVE_THREADS]])
+  // CHECK: [[IS_WARP_MASTER:%.+]] = icmp eq i32 [[LANEID]], 0
+  // CHECK: br i1 [[IS_WARP_MASTER]], label {{%?}}[[DO_COPY:.+]], label {{%?}}[[COPY_ELSE:.+]]
+  //
+  // [[DO_COPY]]
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to float*
+  // CHECK: [[ELT_VAL:%.+]] = load float, float* [[ELT]], align
+  //
+  // CHECK: [[MEDIUM_ELT64:%.+]] = getelementptr inbounds [32 x i64], [32 x i64] addrspace([[SHARED_ADDRSPACE]])* [[TRANSFER_STORAGE]], i64 0, i32 [[WARPID]]
+  // CHECK: [[MEDIUM_ELT:%.+]] = bitcast i64 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT64]] to float addrspace([[SHARED_ADDRSPACE]])*
+  // CHECK: store float [[ELT_VAL]], float addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT]], align
+  // CHECK: br label {{%?}}[[COPY_CONT:.+]]
+  //
+  // CHECK: [[COPY_ELSE]]
+  // CHECK: br label {{%?}}[[COPY_CONT]]
+  //
+  // Barrier after copy to shared memory storage medium.
+  // CHECK: [[COPY_CONT]]
+  // CHECK: [[WS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+  // CHECK: [[ACTIVE_THREADS:%.+]] = mul nsw i32 [[ACTIVE_WARPS:%.+]], [[WS]]
+  // CHECK: call void @llvm.nvvm.barrier(i32 1, i32 [[ACTIVE_THREADS]])
+  //
+  // Read into warp 0.
+  // CHECK: [[IS_W0_ACTIVE_THREAD:%.+]] = icmp ult i32 [[TID:%.+]], [[ACTIVE_WARPS]]
+  // CHECK: br i1 [[IS_W0_ACTIVE_THREAD]], label {{%?}}[[DO_READ:.+]], label {{%?}}[[READ_ELSE:.+]]
+  //
+  // CHECK: [[DO_READ]]
+  // CHECK: [[MEDIUM_ELT64:%.+]] = getelementptr inbounds [32 x i64], [32 x i64] addrspace([[SHARED_ADDRSPACE]])* [[TRANSFER_STORAGE]], i64 0, i32 [[TID]]
+  // CHECK: [[MEDIUM_ELT:%.+]] = bitcast i64 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT64]] to float addrspace([[SHARED_ADDRSPACE]])*
+  // CHECK: [[MEDIUM_ELT_VAL:%.+]] = load float, float addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT]], align
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to float*
+  // CHECK: store float [[MEDIUM_ELT_VAL]], float* [[ELT]], align
+  // CHECK: br label {{%?}}[[READ_CONT:.+]]
+  //
+  // CHECK: [[READ_ELSE]]
+  // CHECK: br label {{%?}}[[READ_CONT]]
+  //
+  // CHECK: [[READ_CONT]]
+  // CHECK: call void @llvm.nvvm.barrier(i32 1, i32 [[ACTIVE_THREADS]])
+  // CHECK: ret
+
+
+
+
+
+
+
+
+
+
+  // CHECK: define {{.*}}void {{@__omp_offloading_.+template.+l38}}(
+  //
+  // CHECK: call void @__kmpc_spmd_kernel_init(
+  // CHECK: br label {{%?}}[[EXECUTE:.+]]
+  //
+  // CHECK: [[EXECUTE]]
+  // CHECK: {{call|invoke}} void [[PFN2:@.+]](i32*
+  // CHECK: call void @__kmpc_spmd_kernel_deinit()
+  //
+  //
+  // define internal void [[PFN2]](
+  // CHECK: store i32 0, i32* [[A:%.+]], align
+  // CHECK: store i16 -32768, i16* [[B:%.+]], align
+  // CHECK: [[A_VAL:%.+]] = load i32, i32* [[A:%.+]], align
+  // CHECK: [[OR:%.+]] = or i32 [[A_VAL]], 1
+  // CHECK: store i32 [[OR]], i32* [[A]], align
+  // CHECK: [[BV16:%.+]] = load i16, i16* [[B]], align
+  // CHECK: [[BV:%.+]] = sext i16 [[BV16]] to i32
+  // CHECK: [[CMP:%.+]] = icmp sgt i32 99, [[BV]]
+  // CHECK: br i1 [[CMP]], label {{%?}}[[DO_MAX:.+]], label {{%?}}[[MAX_ELSE:.+]]
+  //
+  // CHECK: [[DO_MAX]]
+  // CHECK: br label {{%?}}[[MAX_CONT:.+]]
+  //
+  // CHECK: [[MAX_ELSE]]
+  // CHECK: [[BV:%.+]] = load i16, i16* [[B]], align
+  // CHECK: [[MAX:%.+]] = sext i16 [[BV]] to i32
+  // CHECK: br label {{%?}}[[MAX_CONT]]
+  //
+  // CHECK: [[MAX_CONT]]
+  // CHECK: [[B_LVALUE:%.+]] = phi i32 [ 99, %[[DO_MAX]] ], [ [[MAX]], %[[MAX_ELSE]] ]
+  // CHECK: [[TRUNC:%.+]] = trunc i32 [[B_LVALUE]] to i16
+  // CHECK: store i16 [[TRUNC]], i16* [[B]], align
+  // CHECK: [[PTR1:%.+]] = getelementptr inbounds [[RLT:.+]], [2 x i8*]* [[RL:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[A_CAST:%.+]] = bitcast i32* [[A]] to i8*
+  // CHECK: store i8* [[A_CAST]], i8** [[PTR1]], align
+  // CHECK: [[PTR2:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RL]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[B_CAST:%.+]] = bitcast i16* [[B]] to i8*
+  // CHECK: store i8* [[B_CAST]], i8** [[PTR2]], align
+  // CHECK: [[ARG_RL:%.+]] = bitcast [[RLT]]* [[RL]] to i8*
+  // CHECK: [[RET:%.+]] = call i32 @__kmpc_nvptx_parallel_reduce_nowait(i32 {{.+}}, i32 2, i{{32|64}} {{8|16}}, i8* [[ARG_RL]], void (i8*, i16, i16, i16)* [[SHUFFLE_REDUCE_FN:@.+]], void (i8*, i32)* [[WARP_COPY_FN:@.+]])
+  // CHECK: switch i32 [[RET]], label {{%?}}[[DEFAULTLABEL:.+]] [
+  // CHECK: i32 1, label {{%?}}[[REDLABEL:.+]]
+
+  // CHECK: [[REDLABEL]]
+  // CHECK: [[A_INV:%.+]] = load i32, i32* [[A_IN:%.+]], align
+  // CHECK: [[AV:%.+]] = load i32, i32* [[A]], align
+  // CHECK: [[OR:%.+]] = or i32 [[A_INV]], [[AV]]
+  // CHECK: store i32 [[OR]], i32* [[A_IN]], align
+  // CHECK: [[B_INV16:%.+]] = load i16, i16* [[B_IN:%.+]], align
+  // CHECK: [[B_INV:%.+]] = sext i16 [[B_INV16]] to i32
+  // CHECK: [[BV16:%.+]] = load i16, i16* [[B]], align
+  // CHECK: [[BV:%.+]] = sext i16 [[BV16]] to i32
+  // CHECK: [[CMP:%.+]] = icmp sgt i32 [[B_INV]], [[BV]]
+  // CHECK: br i1 [[CMP]], label {{%?}}[[DO_MAX:.+]], label {{%?}}[[MAX_ELSE:.+]]
+  //
+  // CHECK: [[DO_MAX]]
+  // CHECK: [[MAX1:%.+]] = load i16, i16* [[B_IN]], align
+  // CHECK: br label {{%?}}[[MAX_CONT:.+]]
+  //
+  // CHECK: [[MAX_ELSE]]
+  // CHECK: [[MAX2:%.+]] = load i16, i16* [[B]], align
+  // CHECK: br label {{%?}}[[MAX_CONT]]
+  //
+  // CHECK: [[MAX_CONT]]
+  // CHECK: [[B_MAX:%.+]] = phi i16 [ [[MAX1]], %[[DO_MAX]] ], [ [[MAX2]], %[[MAX_ELSE]] ]
+  // CHECK: store i16 [[B_MAX]], i16* [[B_IN]], align
+  // CHECK: call void @__kmpc_nvptx_end_reduce_nowait(
+  // CHECK: br label %[[DEFAULTLABEL]]
+  //
+  // CHECK: [[DEFAULTLABEL]]
+  // CHECK: ret
+
+  //
+  // Reduction function
+  // CHECK: define internal void [[REDUCTION_FUNC:@.+]](i8*, i8*)
+  // CHECK: [[VAR1_RHS_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST_RHS:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[VAR1_RHS_VOID:%.+]] = load i8*, i8** [[VAR1_RHS_REF]],
+  // CHECK: [[VAR1_RHS:%.+]] = bitcast i8* [[VAR1_RHS_VOID]] to i32*
+  //
+  // CHECK: [[VAR1_LHS_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST_LHS:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[VAR1_LHS_VOID:%.+]] = load i8*, i8** [[VAR1_LHS_REF]],
+  // CHECK: [[VAR1_LHS:%.+]] = bitcast i8* [[VAR1_LHS_VOID]] to i32*
+  //
+  // CHECK: [[VAR2_RHS_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST_RHS]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[VAR2_RHS_VOID:%.+]] = load i8*, i8** [[VAR2_RHS_REF]],
+  // CHECK: [[VAR2_RHS:%.+]] = bitcast i8* [[VAR2_RHS_VOID]] to i16*
+  //
+  // CHECK: [[VAR2_LHS_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST_LHS]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[VAR2_LHS_VOID:%.+]] = load i8*, i8** [[VAR2_LHS_REF]],
+  // CHECK: [[VAR2_LHS:%.+]] = bitcast i8* [[VAR2_LHS_VOID]] to i16*
+  //
+  // CHECK: [[VAR1_LHS_VAL:%.+]] = load i32, i32* [[VAR1_LHS]],
+  // CHECK: [[VAR1_RHS_VAL:%.+]] = load i32, i32* [[VAR1_RHS]],
+  // CHECK: [[OR:%.+]] = or i32 [[VAR1_LHS_VAL]], [[VAR1_RHS_VAL]]
+  // CHECK: store i32 [[OR]], i32* [[VAR1_LHS]],
+  //
+  // CHECK: [[VAR2_LHS_VAL16:%.+]] = load i16, i16* [[VAR2_LHS]],
+  // CHECK: [[VAR2_LHS_VAL:%.+]] = sext i16 [[VAR2_LHS_VAL16]] to i32
+  // CHECK: [[VAR2_RHS_VAL16:%.+]] = load i16, i16* [[VAR2_RHS]],
+  // CHECK: [[VAR2_RHS_VAL:%.+]] = sext i16 [[VAR2_RHS_VAL16]] to i32
+  //
+  // CHECK: [[CMP:%.+]] = icmp sgt i32 [[VAR2_LHS_VAL]], [[VAR2_RHS_VAL]]
+  // CHECK: br i1 [[CMP]], label {{%?}}[[DO_MAX:.+]], label {{%?}}[[MAX_ELSE:.+]]
+  //
+  // CHECK: [[DO_MAX]]
+  // CHECK: [[MAX1:%.+]] = load i16, i16* [[VAR2_LHS]], align
+  // CHECK: br label {{%?}}[[MAX_CONT:.+]]
+  //
+  // CHECK: [[MAX_ELSE]]
+  // CHECK: [[MAX2:%.+]] = load i16, i16* [[VAR2_RHS]], align
+  // CHECK: br label {{%?}}[[MAX_CONT]]
+  //
+  // CHECK: [[MAX_CONT]]
+  // CHECK: [[MAXV:%.+]] = phi i16 [ [[MAX1]], %[[DO_MAX]] ], [ [[MAX2]], %[[MAX_ELSE]] ]
+  // CHECK: store i16 [[MAXV]], i16* [[VAR2_LHS]],
+  // CHECK: ret void
+
+  //
+  // Shuffle and reduce function
+  // CHECK: define internal void [[SHUFFLE_REDUCE_FN]](i8*, i16 {{.*}}, i16 {{.*}}, i16 {{.*}})
+  // CHECK: [[REMOTE_RED_LIST:%.+]] = alloca [[RLT]], align
+  // CHECK: [[REMOTE_ELT1:%.+]] = alloca i32
+  // CHECK: [[REMOTE_ELT2:%.+]] = alloca i16
+  //
+  // CHECK: [[LANEID:%.+]] = load i16, i16* {{.+}}, align
+  // CHECK: [[LANEOFFSET:%.+]] = load i16, i16* {{.+}}, align
+  // CHECK: [[ALGVER:%.+]] = load i16, i16* {{.+}}, align
+  //
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[REMOTE_ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[REMOTE_RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to i32*
+  // CHECK: [[ELT_VAL:%.+]] = load i32, i32* [[ELT]], align
+  //
+  // CHECK: [[WS32:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+  // CHECK: [[WS:%.+]] = trunc i32 [[WS32]] to i16
+  // CHECK: [[REMOTE_ELT1_VAL:%.+]] = call i32 @__kmpc_shuffle_int32(i32 [[ELT_VAL]], i16 [[LANEOFFSET]], i16 [[WS]])
+  //
+  // CHECK: store i32 [[REMOTE_ELT1_VAL]], i32* [[REMOTE_ELT1]], align
+  // CHECK: [[REMOTE_ELT1C:%.+]] = bitcast i32* [[REMOTE_ELT1]] to i8*
+  // CHECK: store i8* [[REMOTE_ELT1C]], i8** [[REMOTE_ELT_REF]], align
+  //
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[REMOTE_ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[REMOTE_RED_LIST]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to i16*
+  // CHECK: [[ELT_VAL:%.+]] = load i16, i16* [[ELT]], align
+  //
+  // CHECK: [[ELT_CAST:%.+]] = sext i16 [[ELT_VAL]] to i32
+  // CHECK: [[WS32:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+  // CHECK: [[WS:%.+]] = trunc i32 [[WS32]] to i16
+  // CHECK: [[REMOTE_ELT2_VAL32:%.+]] = call i32 @__kmpc_shuffle_int32(i32 [[ELT_CAST]], i16 [[LANEOFFSET]], i16 [[WS]])
+  // CHECK: [[REMOTE_ELT2_VAL:%.+]] = trunc i32 [[REMOTE_ELT2_VAL32]] to i16
+  //
+  // CHECK: store i16 [[REMOTE_ELT2_VAL]], i16* [[REMOTE_ELT2]], align
+  // CHECK: [[REMOTE_ELT2C:%.+]] = bitcast i16* [[REMOTE_ELT2]] to i8*
+  // CHECK: store i8* [[REMOTE_ELT2C]], i8** [[REMOTE_ELT_REF]], align
+  //
+  // Condition to reduce
+  // CHECK: [[CONDALG0:%.+]] = icmp eq i16 [[ALGVER]], 0
+  //
+  // CHECK: [[COND1:%.+]] = icmp eq i16 [[ALGVER]], 1
+  // CHECK: [[COND2:%.+]] = icmp ult i16 [[LANEID]], [[LANEOFFSET]]
+  // CHECK: [[CONDALG1:%.+]] = and i1 [[COND1]], [[COND2]]
+  //
+  // CHECK: [[COND3:%.+]] = icmp eq i16 [[ALGVER]], 2
+  // CHECK: [[COND4:%.+]] = and i16 [[LANEID]], 1
+  // CHECK: [[COND5:%.+]] = icmp eq i16 [[COND4]], 0
+  // CHECK: [[COND6:%.+]] = and i1 [[COND3]], [[COND5]]
+  // CHECK: [[COND7:%.+]] = icmp sgt i16 [[LANEOFFSET]], 0
+  // CHECK: [[CONDALG2:%.+]] = and i1 [[COND6]], [[COND7]]
+  //
+  // CHECK: [[COND8:%.+]] = or i1 [[CONDALG0]], [[CONDALG1]]
+  // CHECK: [[SHOULD_REDUCE:%.+]] = or i1 [[COND8]], [[CONDALG2]]
+  // CHECK: br i1 [[SHOULD_REDUCE]], label {{%?}}[[DO_REDUCE:.+]], label {{%?}}[[REDUCE_ELSE:.+]]
+  //
+  // CHECK: [[DO_REDUCE]]
+  // CHECK: [[RED_LIST1_VOID:%.+]] = bitcast [[RLT]]* [[RED_LIST]] to i8*
+  // CHECK: [[RED_LIST2_VOID:%.+]] = bitcast [[RLT]]* [[REMOTE_RED_LIST]] to i8*
+  // CHECK: call void [[REDUCTION_FUNC]](i8* [[RED_LIST1_VOID]], i8* [[RED_LIST2_VOID]])
+  // CHECK: br label {{%?}}[[REDUCE_CONT:.+]]
+  //
+  // CHECK: [[REDUCE_ELSE]]
+  // CHECK: br label {{%?}}[[REDUCE_CONT]]
+  //
+  // CHECK: [[REDUCE_CONT]]
+  // Now check if we should just copy over the remote reduction list
+  // CHECK: [[COND1:%.+]] = icmp eq i16 [[ALGVER]], 1
+  // CHECK: [[COND2:%.+]] = icmp uge i16 [[LANEID]], [[LANEOFFSET]]
+  // CHECK: [[SHOULD_COPY:%.+]] = and i1 [[COND1]], [[COND2]]
+  // CHECK: br i1 [[SHOULD_COPY]], label {{%?}}[[DO_COPY:.+]], label {{%?}}[[COPY_ELSE:.+]]
+  //
+  // CHECK: [[DO_COPY]]
+  // CHECK: [[REMOTE_ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[REMOTE_RED_LIST]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[REMOTE_ELT_VOID:%.+]] = load i8*, i8** [[REMOTE_ELT_REF]],
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to i32*
+  // CHECK: [[REMOTE_ELT:%.+]] = bitcast i8* [[REMOTE_ELT_VOID]] to i32*
+  // CHECK: [[REMOTE_ELT_VAL:%.+]] = load i32, i32* [[REMOTE_ELT]], align
+  // CHECK: store i32 [[REMOTE_ELT_VAL]], i32* [[ELT]], align
+  //
+  // CHECK: [[REMOTE_ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[REMOTE_RED_LIST]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[REMOTE_ELT_VOID:%.+]] = load i8*, i8** [[REMOTE_ELT_REF]],
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to i16*
+  // CHECK: [[REMOTE_ELT:%.+]] = bitcast i8* [[REMOTE_ELT_VOID]] to i16*
+  // CHECK: [[REMOTE_ELT_VAL:%.+]] = load i16, i16* [[REMOTE_ELT]], align
+  // CHECK: store i16 [[REMOTE_ELT_VAL]], i16* [[ELT]], align
+  // CHECK: br label {{%?}}[[COPY_CONT:.+]]
+  //
+  // CHECK: [[COPY_ELSE]]
+  // CHECK: br label {{%?}}[[COPY_CONT]]
+  //
+  // CHECK: [[COPY_CONT]]
+  // CHECK: void
+
+  //
+  // Inter warp copy function
+  // CHECK: define internal void [[WARP_COPY_FN]](i8*, i32)
+  // CHECK-DAG: [[LANEID:%.+]] = and i32 {{.+}}, 31
+  // CHECK-DAG: [[WARPID:%.+]] = ashr i32 {{.+}}, 5
+  // CHECK-DAG: [[RED_LIST:%.+]] = bitcast i8* {{.+}} to [[RLT]]*
+  // CHECK: [[IS_WARP_MASTER:%.+]] = icmp eq i32 [[LANEID]], 0
+  // CHECK: br i1 [[IS_WARP_MASTER]], label {{%?}}[[DO_COPY:.+]], label {{%?}}[[COPY_ELSE:.+]]
+  //
+  // [[DO_COPY]]
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to i32*
+  // CHECK: [[ELT_VAL:%.+]] = load i32, i32* [[ELT]], align
+  //
+  // CHECK: [[MEDIUM_ELT64:%.+]] = getelementptr inbounds [32 x i64], [32 x i64] addrspace([[SHARED_ADDRSPACE]])* [[TRANSFER_STORAGE]], i64 0, i32 [[WARPID]]
+  // CHECK: [[MEDIUM_ELT:%.+]] = bitcast i64 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT64]] to i32 addrspace([[SHARED_ADDRSPACE]])*
+  // CHECK: store i32 [[ELT_VAL]], i32 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT]], align
+  // CHECK: br label {{%?}}[[COPY_CONT:.+]]
+  //
+  // CHECK: [[COPY_ELSE]]
+  // CHECK: br label {{%?}}[[COPY_CONT]]
+  //
+  // Barrier after copy to shared memory storage medium.
+  // CHECK: [[COPY_CONT]]
+  // CHECK: [[WS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+  // CHECK: [[ACTIVE_THREADS:%.+]] = mul nsw i32 [[ACTIVE_WARPS:%.+]], [[WS]]
+  // CHECK: call void @llvm.nvvm.barrier(i32 1, i32 [[ACTIVE_THREADS]])
+  //
+  // Read into warp 0.
+  // CHECK: [[IS_W0_ACTIVE_THREAD:%.+]] = icmp ult i32 [[TID:%.+]], [[ACTIVE_WARPS]]
+  // CHECK: br i1 [[IS_W0_ACTIVE_THREAD]], label {{%?}}[[DO_READ:.+]], label {{%?}}[[READ_ELSE:.+]]
+  //
+  // CHECK: [[DO_READ]]
+  // CHECK: [[MEDIUM_ELT64:%.+]] = getelementptr inbounds [32 x i64], [32 x i64] addrspace([[SHARED_ADDRSPACE]])* [[TRANSFER_STORAGE]], i64 0, i32 [[TID]]
+  // CHECK: [[MEDIUM_ELT:%.+]] = bitcast i64 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT64]] to i32 addrspace([[SHARED_ADDRSPACE]])*
+  // CHECK: [[MEDIUM_ELT_VAL:%.+]] = load i32, i32 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT]], align
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 0
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to i32*
+  // CHECK: store i32 [[MEDIUM_ELT_VAL]], i32* [[ELT]], align
+  // CHECK: br label {{%?}}[[READ_CONT:.+]]
+  //
+  // CHECK: [[READ_ELSE]]
+  // CHECK: br label {{%?}}[[READ_CONT]]
+  //
+  // CHECK: [[READ_CONT]]
+  // CHECK: call void @llvm.nvvm.barrier(i32 1, i32 [[ACTIVE_THREADS]])
+  // CHECK: [[IS_WARP_MASTER:%.+]] = icmp eq i32 [[LANEID]], 0
+  // CHECK: br i1 [[IS_WARP_MASTER]], label {{%?}}[[DO_COPY:.+]], label {{%?}}[[COPY_ELSE:.+]]
+  //
+  // [[DO_COPY]]
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to i16*
+  // CHECK: [[ELT_VAL:%.+]] = load i16, i16* [[ELT]], align
+  //
+  // CHECK: [[MEDIUM_ELT64:%.+]] = getelementptr inbounds [32 x i64], [32 x i64] addrspace([[SHARED_ADDRSPACE]])* [[TRANSFER_STORAGE]], i64 0, i32 [[WARPID]]
+  // CHECK: [[MEDIUM_ELT:%.+]] = bitcast i64 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT64]] to i16 addrspace([[SHARED_ADDRSPACE]])*
+  // CHECK: store i16 [[ELT_VAL]], i16 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT]], align
+  // CHECK: br label {{%?}}[[COPY_CONT:.+]]
+  //
+  // CHECK: [[COPY_ELSE]]
+  // CHECK: br label {{%?}}[[COPY_CONT]]
+  //
+  // Barrier after copy to shared memory storage medium.
+  // CHECK: [[COPY_CONT]]
+  // CHECK: [[WS:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.warpsize()
+  // CHECK: [[ACTIVE_THREADS:%.+]] = mul nsw i32 [[ACTIVE_WARPS:%.+]], [[WS]]
+  // CHECK: call void @llvm.nvvm.barrier(i32 1, i32 [[ACTIVE_THREADS]])
+  //
+  // Read into warp 0.
+  // CHECK: [[IS_W0_ACTIVE_THREAD:%.+]] = icmp ult i32 [[TID:%.+]], [[ACTIVE_WARPS]]
+  // CHECK: br i1 [[IS_W0_ACTIVE_THREAD]], label {{%?}}[[DO_READ:.+]], label {{%?}}[[READ_ELSE:.+]]
+  //
+  // CHECK: [[DO_READ]]
+  // CHECK: [[MEDIUM_ELT64:%.+]] = getelementptr inbounds [32 x i64], [32 x i64] addrspace([[SHARED_ADDRSPACE]])* [[TRANSFER_STORAGE]], i64 0, i32 [[TID]]
+  // CHECK: [[MEDIUM_ELT:%.+]] = bitcast i64 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT64]] to i16 addrspace([[SHARED_ADDRSPACE]])*
+  // CHECK: [[MEDIUM_ELT_VAL:%.+]] = load i16, i16 addrspace([[SHARED_ADDRSPACE]])* [[MEDIUM_ELT]], align
+  // CHECK: [[ELT_REF:%.+]] = getelementptr inbounds [[RLT]], [[RLT]]* [[RED_LIST:%.+]], i{{32|64}} 0, i{{32|64}} 1
+  // CHECK: [[ELT_VOID:%.+]] = load i8*, i8** [[ELT_REF]],
+  // CHECK: [[ELT:%.+]] = bitcast i8* [[ELT_VOID]] to i16*
+  // CHECK: store i16 [[MEDIUM_ELT_VAL]], i16* [[ELT]], align
+  // CHECK: br label {{%?}}[[READ_CONT:.+]]
+  //
+  // CHECK: [[READ_ELSE]]
+  // CHECK: br label {{%?}}[[READ_CONT]]
+  //
+  // CHECK: [[READ_CONT]]
+  // CHECK: call void @llvm.nvvm.barrier(i32 1, i32 [[ACTIVE_THREADS]])
+  // CHECK: ret
+
+#endif