[Polly] Remove Polly-ACC.

Polly-ACC is unmaintained and since it has never been ported to the NPM pipeline, since D136621 it is not even accessible anymore without manually specifying the passes on the `opt` command line.

Since there is no plan to put it to a maintainable state, remove it from Polly.

Reviewed By: grosser

Differential Revision: https://reviews.llvm.org/D142580

1 files changed, 0 insertions, 3657 deletions

diff --git a/polly/lib/CodeGen/PPCGCodeGeneration.cpp b/polly/lib/CodeGen/PPCGCodeGeneration.cpp
deleted file mode 100644
index 41b90bc976c2..000000000000
--- a/polly/lib/CodeGen/PPCGCodeGeneration.cpp
+++ /dev/null
@@ -1,3657 +0,0 @@
-//===------ PPCGCodeGeneration.cpp - Polly Accelerator Code Generation. ---===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-//
-// Take a scop created by ScopInfo and map it to GPU code using the ppcg
-// GPU mapping strategy.
-//
-//===----------------------------------------------------------------------===//
-
-#include "polly/CodeGen/PPCGCodeGeneration.h"
-#include "polly/CodeGen/CodeGeneration.h"
-#include "polly/CodeGen/IslAst.h"
-#include "polly/CodeGen/IslNodeBuilder.h"
-#include "polly/CodeGen/PerfMonitor.h"
-#include "polly/CodeGen/Utils.h"
-#include "polly/DependenceInfo.h"
-#include "polly/LinkAllPasses.h"
-#include "polly/Options.h"
-#include "polly/ScopDetection.h"
-#include "polly/ScopInfo.h"
-#include "polly/Support/ISLTools.h"
-#include "polly/Support/SCEVValidator.h"
-#include "llvm/ADT/PostOrderIterator.h"
-#include "llvm/Analysis/TargetTransformInfo.h"
-#include "llvm/IR/IntrinsicsNVPTX.h"
-#include "llvm/IR/LegacyPassManager.h"
-#include "llvm/IR/Verifier.h"
-#include "llvm/IRReader/IRReader.h"
-#include "llvm/InitializePasses.h"
-#include "llvm/Linker/Linker.h"
-#include "llvm/MC/TargetRegistry.h"
-#include "llvm/Support/SourceMgr.h"
-#include "llvm/Target/TargetMachine.h"
-#include "llvm/Transforms/IPO/PassManagerBuilder.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "isl/union_map.h"
-#include <algorithm>
-
-extern "C" {
-#include "ppcg/cuda.h"
-#include "ppcg/gpu.h"
-#include "ppcg/ppcg.h"
-}
-
-#include "llvm/Support/Debug.h"
-
-using namespace polly;
-using namespace llvm;
-
-#define DEBUG_TYPE "polly-codegen-ppcg"
-
-static cl::opt<bool> DumpSchedule("polly-acc-dump-schedule",
-                                  cl::desc("Dump the computed GPU Schedule"),
-                                  cl::Hidden, cl::cat(PollyCategory));
-
-static cl::opt<bool>
-    DumpCode("polly-acc-dump-code",
-             cl::desc("Dump C code describing the GPU mapping"), cl::Hidden,
-             cl::cat(PollyCategory));
-
-static cl::opt<bool> DumpKernelIR("polly-acc-dump-kernel-ir",
-                                  cl::desc("Dump the kernel LLVM-IR"),
-                                  cl::Hidden, cl::cat(PollyCategory));
-
-static cl::opt<bool> DumpKernelASM("polly-acc-dump-kernel-asm",
-                                   cl::desc("Dump the kernel assembly code"),
-                                   cl::Hidden, cl::cat(PollyCategory));
-
-static cl::opt<bool> FastMath("polly-acc-fastmath",
-                              cl::desc("Allow unsafe math optimizations"),
-                              cl::Hidden, cl::cat(PollyCategory));
-static cl::opt<bool> SharedMemory("polly-acc-use-shared",
-                                  cl::desc("Use shared memory"), cl::Hidden,
-                                  cl::cat(PollyCategory));
-static cl::opt<bool> PrivateMemory("polly-acc-use-private",
-                                   cl::desc("Use private memory"), cl::Hidden,
-                                   cl::cat(PollyCategory));
-
-bool polly::PollyManagedMemory;
-static cl::opt<bool, true>
-    XManagedMemory("polly-acc-codegen-managed-memory",
-                   cl::desc("Generate Host kernel code assuming"
-                            " that all memory has been"
-                            " declared as managed memory"),
-                   cl::location(PollyManagedMemory), cl::Hidden,
-                   cl::init(false), cl::cat(PollyCategory));
-
-static cl::opt<bool>
-    FailOnVerifyModuleFailure("polly-acc-fail-on-verify-module-failure",
-                              cl::desc("Fail and generate a backtrace if"
-                                       " verifyModule fails on the GPU "
-                                       " kernel module."),
-                              cl::Hidden, cl::cat(PollyCategory));
-
-static cl::opt<std::string> CUDALibDevice(
-    "polly-acc-libdevice", cl::desc("Path to CUDA libdevice"), cl::Hidden,
-    cl::init("/usr/local/cuda/nvvm/libdevice/libdevice.compute_20.10.ll"),
-    cl::cat(PollyCategory));
-
-static cl::opt<std::string>
-    CudaVersion("polly-acc-cuda-version",
-                cl::desc("The CUDA version to compile for"), cl::Hidden,
-                cl::init("sm_30"), cl::cat(PollyCategory));
-
-static cl::opt<int>
-    MinCompute("polly-acc-mincompute",
-               cl::desc("Minimal number of compute statements to run on GPU."),
-               cl::Hidden, cl::init(10 * 512 * 512));
-
-GPURuntime polly::GPURuntimeChoice;
-static cl::opt<GPURuntime, true>
-    XGPURuntimeChoice("polly-gpu-runtime",
-                      cl::desc("The GPU Runtime API to target"),
-                      cl::values(clEnumValN(GPURuntime::CUDA, "libcudart",
-                                            "use the CUDA Runtime API"),
-                                 clEnumValN(GPURuntime::OpenCL, "libopencl",
-                                            "use the OpenCL Runtime API")),
-                      cl::location(polly::GPURuntimeChoice),
-                      cl::init(GPURuntime::CUDA), cl::cat(PollyCategory));
-
-GPUArch polly::GPUArchChoice;
-static cl::opt<GPUArch, true>
-    XGPUArchChoice("polly-gpu-arch", cl::desc("The GPU Architecture to target"),
-                   cl::values(clEnumValN(GPUArch::NVPTX64, "nvptx64",
-                                         "target NVIDIA 64-bit architecture"),
-                              clEnumValN(GPUArch::SPIR32, "spir32",
-                                         "target SPIR 32-bit architecture"),
-                              clEnumValN(GPUArch::SPIR64, "spir64",
-                                         "target SPIR 64-bit architecture")),
-                   cl::location(polly::GPUArchChoice),
-                   cl::init(GPUArch::NVPTX64), cl::cat(PollyCategory));
-
-extern bool polly::PerfMonitoring;
-
-/// Return  a unique name for a Scop, which is the scop region with the
-/// function name.
-std::string getUniqueScopName(const Scop *S) {
-  return "Scop Region: " + S->getNameStr() +
-         " | Function: " + std::string(S->getFunction().getName());
-}
-
-/// Used to store information PPCG wants for kills. This information is
-/// used by live range reordering.
-///
-/// @see computeLiveRangeReordering
-/// @see GPUNodeBuilder::createPPCGScop
-/// @see GPUNodeBuilder::createPPCGProg
-struct MustKillsInfo {
-  /// Collection of all kill statements that will be sequenced at the end of
-  /// PPCGScop->schedule.
-  ///
-  /// The nodes in `KillsSchedule` will be merged using `isl_schedule_set`
-  /// which merges schedules in *arbitrary* order.
-  /// (we don't care about the order of the kills anyway).
-  isl::schedule KillsSchedule;
-  /// Map from kill statement instances to scalars that need to be
-  /// killed.
-  ///
-  /// We currently derive kill information for:
-  ///  1. phi nodes. PHI nodes are not alive outside the scop and can
-  ///     consequently all be killed.
-  ///  2. Scalar arrays that are not used outside the Scop. This is
-  ///     checked by `isScalarUsesContainedInScop`.
-  /// [params] -> { [Stmt_phantom[] -> ref_phantom[]] -> scalar_to_kill[] }
-  isl::union_map TaggedMustKills;
-
-  /// Tagged must kills stripped of the tags.
-  /// [params] -> { Stmt_phantom[]  -> scalar_to_kill[] }
-  isl::union_map MustKills;
-
-  MustKillsInfo() : KillsSchedule() {}
-};
-
-/// Check if SAI's uses are entirely contained within Scop S.
-/// If a scalar is used only with a Scop, we are free to kill it, as no data
-/// can flow in/out of the value any more.
-/// @see computeMustKillsInfo
-static bool isScalarUsesContainedInScop(const Scop &S,
-                                        const ScopArrayInfo *SAI) {
-  assert(SAI->isValueKind() && "this function only deals with scalars."
-                               " Dealing with arrays required alias analysis");
-
-  const Region &R = S.getRegion();
-  for (User *U : SAI->getBasePtr()->users()) {
-    Instruction *I = dyn_cast<Instruction>(U);
-    assert(I && "invalid user of scop array info");
-    if (!R.contains(I))
-      return false;
-  }
-  return true;
-}
-
-/// Compute must-kills needed to enable live range reordering with PPCG.
-///
-/// @params S The Scop to compute live range reordering information
-/// @returns live range reordering information that can be used to setup
-/// PPCG.
-static MustKillsInfo computeMustKillsInfo(const Scop &S) {
-  const isl::space ParamSpace = S.getParamSpace();
-  MustKillsInfo Info;
-
-  // 1. Collect all ScopArrayInfo that satisfy *any* of the criteria:
-  //      1.1 phi nodes in scop.
-  //      1.2 scalars that are only used within the scop
-  SmallVector<isl::id, 4> KillMemIds;
-  for (ScopArrayInfo *SAI : S.arrays()) {
-    if (SAI->isPHIKind() ||
-        (SAI->isValueKind() && isScalarUsesContainedInScop(S, SAI)))
-      KillMemIds.push_back(isl::manage(SAI->getBasePtrId().release()));
-  }
-
-  Info.TaggedMustKills = isl::union_map::empty(ParamSpace.ctx());
-  Info.MustKills = isl::union_map::empty(ParamSpace.ctx());
-
-  // Initialising KillsSchedule to `isl_set_empty` creates an empty node in the
-  // schedule:
-  //     - filter: "[control] -> { }"
-  // So, we choose to not create this to keep the output a little nicer,
-  // at the cost of some code complexity.
-  Info.KillsSchedule = {};
-
-  for (isl::id &ToKillId : KillMemIds) {
-    isl::id KillStmtId = isl::id::alloc(
-        S.getIslCtx(),
-        std::string("SKill_phantom_").append(ToKillId.get_name()), nullptr);
-
-    // NOTE: construction of tagged_must_kill:
-    // 2. We need to construct a map:
-    //     [param] -> { [Stmt_phantom[] -> ref_phantom[]] -> scalar_to_kill[] }
-    // To construct this, we use `isl_map_domain_product` on 2 maps`:
-    // 2a. StmtToScalar:
-    //         [param] -> { Stmt_phantom[] -> scalar_to_kill[] }
-    // 2b. PhantomRefToScalar:
-    //         [param] -> { ref_phantom[] -> scalar_to_kill[] }
-    //
-    // Combining these with `isl_map_domain_product` gives us
-    // TaggedMustKill:
-    //     [param] -> { [Stmt[] -> phantom_ref[]] -> scalar_to_kill[] }
-
-    // 2a. [param] -> { Stmt[] -> scalar_to_kill[] }
-    isl::map StmtToScalar = isl::map::universe(ParamSpace);
-    StmtToScalar = StmtToScalar.set_tuple_id(isl::dim::in, isl::id(KillStmtId));
-    StmtToScalar = StmtToScalar.set_tuple_id(isl::dim::out, isl::id(ToKillId));
-
-    isl::id PhantomRefId = isl::id::alloc(
-        S.getIslCtx(), std::string("ref_phantom") + ToKillId.get_name(),
-        nullptr);
-
-    // 2b. [param] -> { phantom_ref[] -> scalar_to_kill[] }
-    isl::map PhantomRefToScalar = isl::map::universe(ParamSpace);
-    PhantomRefToScalar =
-        PhantomRefToScalar.set_tuple_id(isl::dim::in, PhantomRefId);
-    PhantomRefToScalar =
-        PhantomRefToScalar.set_tuple_id(isl::dim::out, ToKillId);
-
-    // 2. [param] -> { [Stmt[] -> phantom_ref[]] -> scalar_to_kill[] }
-    isl::map TaggedMustKill = StmtToScalar.domain_product(PhantomRefToScalar);
-    Info.TaggedMustKills = Info.TaggedMustKills.unite(TaggedMustKill);
-
-    // 2. [param] -> { Stmt[] -> scalar_to_kill[] }
-    Info.MustKills = Info.TaggedMustKills.domain_factor_domain();
-
-    // 3. Create the kill schedule of the form:
-    //     "[param] -> { Stmt_phantom[] }"
-    // Then add this to Info.KillsSchedule.
-    isl::space KillStmtSpace = ParamSpace;
-    KillStmtSpace = KillStmtSpace.set_tuple_id(isl::dim::set, KillStmtId);
-    isl::union_set KillStmtDomain = isl::set::universe(KillStmtSpace);
-
-    isl::schedule KillSchedule = isl::schedule::from_domain(KillStmtDomain);
-    if (!Info.KillsSchedule.is_null())
-      Info.KillsSchedule = isl::manage(
-          isl_schedule_set(Info.KillsSchedule.release(), KillSchedule.copy()));
-    else
-      Info.KillsSchedule = KillSchedule;
-  }
-
-  return Info;
-}
-
-/// Create the ast expressions for a ScopStmt.
-///
-/// This function is a callback for to generate the ast expressions for each
-/// of the scheduled ScopStmts.
-static __isl_give isl_id_to_ast_expr *pollyBuildAstExprForStmt(
-    void *StmtT, __isl_take isl_ast_build *Build_C,
-    isl_multi_pw_aff *(*FunctionIndex)(__isl_take isl_multi_pw_aff *MPA,
-                                       isl_id *Id, void *User),
-    void *UserIndex,
-    isl_ast_expr *(*FunctionExpr)(isl_ast_expr *Expr, isl_id *Id, void *User),
-    void *UserExpr) {
-
-  ScopStmt *Stmt = (ScopStmt *)StmtT;
-
-  if (!Stmt || !Build_C)
-    return NULL;
-
-  isl::ast_build Build = isl::manage_copy(Build_C);
-  isl::ctx Ctx = Build.ctx();
-  isl::id_to_ast_expr RefToExpr = isl::id_to_ast_expr::alloc(Ctx, 0);
-
-  Stmt->setAstBuild(Build);
-
-  for (MemoryAccess *Acc : *Stmt) {
-    isl::map AddrFunc = Acc->getAddressFunction();
-    AddrFunc = AddrFunc.intersect_domain(Stmt->getDomain());
-
-    isl::id RefId = Acc->getId();
-    isl::pw_multi_aff PMA = isl::pw_multi_aff::from_map(AddrFunc);
-
-    isl::multi_pw_aff MPA = isl::multi_pw_aff(PMA);
-    MPA = MPA.coalesce();
-    MPA = isl::manage(FunctionIndex(MPA.release(), RefId.get(), UserIndex));
-
-    isl::ast_expr Access = Build.access_from(MPA);
-    Access = isl::manage(FunctionExpr(Access.release(), RefId.get(), UserExpr));
-    RefToExpr = RefToExpr.set(RefId, Access);
-  }
-
-  return RefToExpr.release();
-}
-
-/// Given a LLVM Type, compute its size in bytes,
-static int computeSizeInBytes(const Type *T) {
-  int bytes = T->getPrimitiveSizeInBits() / 8;
-  if (bytes == 0)
-    bytes = T->getScalarSizeInBits() / 8;
-  return bytes;
-}
-
-/// Generate code for a GPU specific isl AST.
-///
-/// The GPUNodeBuilder augments the general existing IslNodeBuilder, which
-/// generates code for general-purpose AST nodes, with special functionality
-/// for generating GPU specific user nodes.
-///
-/// @see GPUNodeBuilder::createUser
-class GPUNodeBuilder final : public IslNodeBuilder {
-public:
-  GPUNodeBuilder(PollyIRBuilder &Builder, ScopAnnotator &Annotator,
-                 const DataLayout &DL, LoopInfo &LI, ScalarEvolution &SE,
-                 DominatorTree &DT, Scop &S, BasicBlock *StartBlock,
-                 gpu_prog *Prog, GPURuntime Runtime, GPUArch Arch)
-      : IslNodeBuilder(Builder, Annotator, DL, LI, SE, DT, S, StartBlock),
-        Prog(Prog), Runtime(Runtime), Arch(Arch) {
-    getExprBuilder().setIDToSAI(&IDToSAI);
-  }
-
-  /// Create after-run-time-check initialization code.
-  void initializeAfterRTH();
-
-  /// Finalize the generated scop.
-  void finalize() override;
-
-  /// Track if the full build process was successful.
-  ///
-  /// This value is set to false, if throughout the build process an error
-  /// occurred which prevents us from generating valid GPU code.
-  bool BuildSuccessful = true;
-
-  /// The maximal number of loops surrounding a sequential kernel.
-  unsigned DeepestSequential = 0;
-
-  /// The maximal number of loops surrounding a parallel kernel.
-  unsigned DeepestParallel = 0;
-
-  /// Return the name to set for the ptx_kernel.
-  std::string getKernelFuncName(int Kernel_id);
-
-private:
-  /// A vector of array base pointers for which a new ScopArrayInfo was created.
-  ///
-  /// This vector is used to delete the ScopArrayInfo when it is not needed any
-  /// more.
-  std::vector<Value *> LocalArrays;
-
-  /// A map from ScopArrays to their corresponding device allocations.
-  std::map<ScopArrayInfo *, Value *> DeviceAllocations;
-
-  /// The current GPU context.
-  Value *GPUContext;
-
-  /// The set of isl_ids allocated in the kernel
-  std::vector<isl_id *> KernelIds;
-
-  /// A module containing GPU code.
-  ///
-  /// This pointer is only set in case we are currently generating GPU code.
-  std::unique_ptr<Module> GPUModule;
-
-  /// The GPU program we generate code for.
-  gpu_prog *Prog;
-
-  /// The GPU Runtime implementation to use (OpenCL or CUDA).
-  GPURuntime Runtime;
-
-  /// The GPU Architecture to target.
-  GPUArch Arch;
-
-  /// Class to free isl_ids.
-  class IslIdDeleter final {
-  public:
-    void operator()(__isl_take isl_id *Id) { isl_id_free(Id); };
-  };
-
-  /// A set containing all isl_ids allocated in a GPU kernel.
-  ///
-  /// By releasing this set all isl_ids will be freed.
-  std::set<std::unique_ptr<isl_id, IslIdDeleter>> KernelIDs;
-
-  IslExprBuilder::IDToScopArrayInfoTy IDToSAI;
-
-  /// Create code for user-defined AST nodes.
-  ///
-  /// These AST nodes can be of type:
-  ///
-  ///   - ScopStmt:      A computational statement (TODO)
-  ///   - Kernel:        A GPU kernel call (TODO)
-  ///   - Data-Transfer: A GPU <-> CPU data-transfer
-  ///   - In-kernel synchronization
-  ///   - In-kernel memory copy statement
-  ///
-  /// @param UserStmt The ast node to generate code for.
-  void createUser(__isl_take isl_ast_node *UserStmt) override;
-
-  void createFor(__isl_take isl_ast_node *Node) override;
-
-  enum DataDirection { HOST_TO_DEVICE, DEVICE_TO_HOST };
-
-  /// Create code for a data transfer statement
-  ///
-  /// @param TransferStmt The data transfer statement.
-  /// @param Direction The direction in which to transfer data.
-  void createDataTransfer(__isl_take isl_ast_node *TransferStmt,
-                          enum DataDirection Direction);
-
-  /// Find llvm::Values referenced in GPU kernel.
-  ///
-  /// @param Kernel The kernel to scan for llvm::Values
-  ///
-  /// @returns A tuple, whose:
-  ///          - First element contains the set of values referenced by the
-  ///            kernel
-  ///          - Second element contains the set of functions referenced by the
-  ///             kernel. All functions in the set satisfy
-  ///             `isValidFunctionInKernel`.
-  ///          - Third element contains loops that have induction variables
-  ///            which are used in the kernel, *and* these loops are *neither*
-  ///            in the scop, nor do they immediately surroung the Scop.
-  ///            See [Code generation of induction variables of loops outside
-  ///            Scops]
-  std::tuple<SetVector<Value *>, SetVector<Function *>, SetVector<const Loop *>,
-             isl::space>
-  getReferencesInKernel(ppcg_kernel *Kernel);
-
-  /// Compute the sizes of the execution grid for a given kernel.
-  ///
-  /// @param Kernel The kernel to compute grid sizes for.
-  ///
-  /// @returns A tuple with grid sizes for X and Y dimension
-  std::tuple<Value *, Value *> getGridSizes(ppcg_kernel *Kernel);
-
-  /// Get the managed array pointer for sending host pointers to the device.
-  /// \note
-  /// This is to be used only with managed memory
-  Value *getManagedDeviceArray(gpu_array_info *Array, ScopArrayInfo *ArrayInfo);
-
-  /// Compute the sizes of the thread blocks for a given kernel.
-  ///
-  /// @param Kernel The kernel to compute thread block sizes for.
-  ///
-  /// @returns A tuple with thread block sizes for X, Y, and Z dimensions.
-  std::tuple<Value *, Value *, Value *> getBlockSizes(ppcg_kernel *Kernel);
-
-  /// Store a specific kernel launch parameter in the array of kernel launch
-  /// parameters.
-  ///
-  /// @param ArrayTy    Array type of \p Parameters.
-  /// @param Parameters The list of parameters in which to store.
-  /// @param Param      The kernel launch parameter to store.
-  /// @param Index      The index in the parameter list, at which to store the
-  ///                   parameter.
-  void insertStoreParameter(Type *ArrayTy, Instruction *Parameters,
-                            Instruction *Param, int Index);
-
-  /// Create kernel launch parameters.
-  ///
-  /// @param Kernel        The kernel to create parameters for.
-  /// @param F             The kernel function that has been created.
-  /// @param SubtreeValues The set of llvm::Values referenced by this kernel.
-  ///
-  /// @returns A stack allocated array with pointers to the parameter
-  ///          values that are passed to the kernel.
-  Value *createLaunchParameters(ppcg_kernel *Kernel, Function *F,
-                                SetVector<Value *> SubtreeValues);
-
-  /// Create declarations for kernel variable.
-  ///
-  /// This includes shared memory declarations.
-  ///
-  /// @param Kernel        The kernel definition to create variables for.
-  /// @param FN            The function into which to generate the variables.
-  void createKernelVariables(ppcg_kernel *Kernel, Function *FN);
-
-  /// Add CUDA annotations to module.
-  ///
-  /// Add a set of CUDA annotations that declares the maximal block dimensions
-  /// that will be used to execute the CUDA kernel. This allows the NVIDIA
-  /// PTX compiler to bound the number of allocated registers to ensure the
-  /// resulting kernel is known to run with up to as many block dimensions
-  /// as specified here.
-  ///
-  /// @param M         The module to add the annotations to.
-  /// @param BlockDimX The size of block dimension X.
-  /// @param BlockDimY The size of block dimension Y.
-  /// @param BlockDimZ The size of block dimension Z.
-  void addCUDAAnnotations(Module *M, Value *BlockDimX, Value *BlockDimY,
-                          Value *BlockDimZ);
-
-  /// Create GPU kernel.
-  ///
-  /// Code generate the kernel described by @p KernelStmt.
-  ///
-  /// @param KernelStmt The ast node to generate kernel code for.
-  void createKernel(__isl_take isl_ast_node *KernelStmt);
-
-  /// Generate code that computes the size of an array.
-  ///
-  /// @param Array The array for which to compute a size.
-  Value *getArraySize(gpu_array_info *Array);
-
-  /// Generate code to compute the minimal offset at which an array is accessed.
-  ///
-  /// The offset of an array is the minimal array location accessed in a scop.
-  ///
-  /// Example:
-  ///
-  ///   for (long i = 0; i < 100; i++)
-  ///     A[i + 42] += ...
-  ///
-  ///   getArrayOffset(A) results in 42.
-  ///
-  /// @param Array The array for which to compute the offset.
-  /// @returns An llvm::Value that contains the offset of the array.
-  Value *getArrayOffset(gpu_array_info *Array);
-
-  /// Prepare the kernel arguments for kernel code generation
-  ///
-  /// @param Kernel The kernel to generate code for.
-  /// @param FN     The function created for the kernel.
-  void prepareKernelArguments(ppcg_kernel *Kernel, Function *FN);
-
-  /// Create kernel function.
-  ///
-  /// Create a kernel function located in a newly created module that can serve
-  /// as target for device code generation. Set the Builder to point to the
-  /// start block of this newly created function.
-  ///
-  /// @param Kernel The kernel to generate code for.
-  /// @param SubtreeValues The set of llvm::Values referenced by this kernel.
-  /// @param SubtreeFunctions The set of llvm::Functions referenced by this
-  ///                         kernel.
-  void createKernelFunction(ppcg_kernel *Kernel,
-                            SetVector<Value *> &SubtreeValues,
-                            SetVector<Function *> &SubtreeFunctions);
-
-  /// Create the declaration of a kernel function.
-  ///
-  /// The kernel function takes as arguments:
-  ///
-  ///   - One i8 pointer for each external array reference used in the kernel.
-  ///   - Host iterators
-  ///   - Parameters
-  ///   - Other LLVM Value references (TODO)
-  ///
-  /// @param Kernel The kernel to generate the function declaration for.
-  /// @param SubtreeValues The set of llvm::Values referenced by this kernel.
-  ///
-  /// @returns The newly declared function.
-  Function *createKernelFunctionDecl(ppcg_kernel *Kernel,
-                                     SetVector<Value *> &SubtreeValues);
-
-  /// Insert intrinsic functions to obtain thread and block ids.
-  ///
-  /// @param The kernel to generate the intrinsic functions for.
-  void insertKernelIntrinsics(ppcg_kernel *Kernel);
-
-  /// Insert function calls to retrieve the SPIR group/local ids.
-  ///
-  /// @param Kernel The kernel to generate the function calls for.
-  /// @param SizeTypeIs64Bit Whether size_t of the openCl device is 64bit.
-  void insertKernelCallsSPIR(ppcg_kernel *Kernel, bool SizeTypeIs64bit);
-
-  /// Setup the creation of functions referenced by the GPU kernel.
-  ///
-  /// 1. Create new function declarations in GPUModule which are the same as
-  /// SubtreeFunctions.
-  ///
-  /// 2. Populate IslNodeBuilder::ValueMap with mappings from
-  /// old functions (that come from the original module) to new functions
-  /// (that are created within GPUModule). That way, we generate references
-  /// to the correct function (in GPUModule) in BlockGenerator.
-  ///
-  /// @see IslNodeBuilder::ValueMap
-  /// @see BlockGenerator::GlobalMap
-  /// @see BlockGenerator::getNewValue
-  /// @see GPUNodeBuilder::getReferencesInKernel.
-  ///
-  /// @param SubtreeFunctions The set of llvm::Functions referenced by
-  ///                         this kernel.
-  void setupKernelSubtreeFunctions(SetVector<Function *> SubtreeFunctions);
-
-  /// Create a global-to-shared or shared-to-global copy statement.
-  ///
-  /// @param CopyStmt The copy statement to generate code for
-  void createKernelCopy(ppcg_kernel_stmt *CopyStmt);
-
-  /// Create code for a ScopStmt called in @p Expr.
-  ///
-  /// @param Expr The expression containing the call.
-  /// @param KernelStmt The kernel statement referenced in the call.
-  void createScopStmt(isl_ast_expr *Expr, ppcg_kernel_stmt *KernelStmt);
-
-  /// Create an in-kernel synchronization call.
-  void createKernelSync();
-
-  /// Create a PTX assembly string for the current GPU kernel.
-  ///
-  /// @returns A string containing the corresponding PTX assembly code.
-  std::string createKernelASM();
-
-  /// Remove references from the dominator tree to the kernel function @p F.
-  ///
-  /// @param F The function to remove references to.
-  void clearDominators(Function *F);
-
-  /// Remove references from scalar evolution to the kernel function @p F.
-  ///
-  /// @param F The function to remove references to.
-  void clearScalarEvolution(Function *F);
-
-  /// Remove references from loop info to the kernel function @p F.
-  ///
-  /// @param F The function to remove references to.
-  void clearLoops(Function *F);
-
-  /// Check if the scop requires to be linked with CUDA's libdevice.
-  bool requiresCUDALibDevice();
-
-  /// Link with the NVIDIA libdevice library (if needed and available).
-  void addCUDALibDevice();
-
-  /// Finalize the generation of the kernel function.
-  ///
-  /// Free the LLVM-IR module corresponding to the kernel and -- if requested --
-  /// dump its IR to stderr.
-  ///
-  /// @returns The Assembly string of the kernel.
-  std::string finalizeKernelFunction();
-
-  /// Finalize the generation of the kernel arguments.
-  ///
-  /// This function ensures that not-read-only scalars used in a kernel are
-  /// stored back to the global memory location they are backed with before
-  /// the kernel terminates.
-  ///
-  /// @params Kernel The kernel to finalize kernel arguments for.
-  void finalizeKernelArguments(ppcg_kernel *Kernel);
-
-  /// Create code that allocates memory to store arrays on device.
-  void allocateDeviceArrays();
-
-  /// Create code to prepare the managed device pointers.
-  void prepareManagedDeviceArrays();
-
-  /// Free all allocated device arrays.
-  void freeDeviceArrays();
-
-  /// Create a call to initialize the GPU context.
-  ///
-  /// @returns A pointer to the newly initialized context.
-  Value *createCallInitContext();
-
-  /// Create a call to get the device pointer for a kernel allocation.
-  ///
-  /// @param Allocation The Polly GPU allocation
-  ///
-  /// @returns The device parameter corresponding to this allocation.
-  Value *createCallGetDevicePtr(Value *Allocation);
-
-  /// Create a call to free the GPU context.
-  ///
-  /// @param Context A pointer to an initialized GPU context.
-  void createCallFreeContext(Value *Context);
-
-  /// Create a call to allocate memory on the device.
-  ///
-  /// @param Size The size of memory to allocate
-  ///
-  /// @returns A pointer that identifies this allocation.
-  Value *createCallAllocateMemoryForDevice(Value *Size);
-
-  /// Create a call to free a device array.
-  ///
-  /// @param Array The device array to free.
-  void createCallFreeDeviceMemory(Value *Array);
-
-  /// Create a call to copy data from host to device.
-  ///
-  /// @param HostPtr A pointer to the host data that should be copied.
-  /// @param DevicePtr A device pointer specifying the location to copy to.
-  void createCallCopyFromHostToDevice(Value *HostPtr, Value *DevicePtr,
-                                      Value *Size);
-
-  /// Create a call to copy data from device to host.
-  ///
-  /// @param DevicePtr A pointer to the device data that should be copied.
-  /// @param HostPtr A host pointer specifying the location to copy to.
-  void createCallCopyFromDeviceToHost(Value *DevicePtr, Value *HostPtr,
-                                      Value *Size);
-
-  /// Create a call to synchronize Host & Device.
-  /// \note
-  /// This is to be used only with managed memory.
-  void createCallSynchronizeDevice();
-
-  /// Create a call to get a kernel from an assembly string.
-  ///
-  /// @param Buffer The string describing the kernel.
-  /// @param Entry  The name of the kernel function to call.
-  ///
-  /// @returns A pointer to a kernel object
-  Value *createCallGetKernel(Value *Buffer, Value *Entry);
-
-  /// Create a call to free a GPU kernel.
-  ///
-  /// @param GPUKernel THe kernel to free.
-  void createCallFreeKernel(Value *GPUKernel);
-
-  /// Create a call to launch a GPU kernel.
-  ///
-  /// @param GPUKernel  The kernel to launch.
-  /// @param GridDimX   The size of the first grid dimension.
-  /// @param GridDimY   The size of the second grid dimension.
-  /// @param GridBlockX The size of the first block dimension.
-  /// @param GridBlockY The size of the second block dimension.
-  /// @param GridBlockZ The size of the third block dimension.
-  /// @param Parameters A pointer to an array that contains itself pointers to
-  ///                   the parameter values passed for each kernel argument.
-  void createCallLaunchKernel(Value *GPUKernel, Value *GridDimX,
-                              Value *GridDimY, Value *BlockDimX,
-                              Value *BlockDimY, Value *BlockDimZ,
-                              Value *Parameters);
-};
-
-std::string GPUNodeBuilder::getKernelFuncName(int Kernel_id) {
-  return "FUNC_" + S.getFunction().getName().str() + "_SCOP_" +
-         std::to_string(S.getID()) + "_KERNEL_" + std::to_string(Kernel_id);
-}
-
-void GPUNodeBuilder::initializeAfterRTH() {
-  BasicBlock *NewBB = SplitBlock(Builder.GetInsertBlock(),
-                                 &*Builder.GetInsertPoint(), &DT, &LI);
-  NewBB->setName("polly.acc.initialize");
-  Builder.SetInsertPoint(&NewBB->front());
-
-  GPUContext = createCallInitContext();
-
-  if (!PollyManagedMemory)
-    allocateDeviceArrays();
-  else
-    prepareManagedDeviceArrays();
-}
-
-void GPUNodeBuilder::finalize() {
-  if (!PollyManagedMemory)
-    freeDeviceArrays();
-
-  createCallFreeContext(GPUContext);
-  IslNodeBuilder::finalize();
-}
-
-void GPUNodeBuilder::allocateDeviceArrays() {
-  assert(!PollyManagedMemory &&
-         "Managed memory will directly send host pointers "
-         "to the kernel. There is no need for device arrays");
-  isl_ast_build *Build = isl_ast_build_from_context(S.getContext().release());
-
-  for (int i = 0; i < Prog->n_array; ++i) {
-    gpu_array_info *Array = &Prog->array[i];
-    auto *ScopArray = (ScopArrayInfo *)Array->user;
-    std::string DevArrayName("p_dev_array_");
-    DevArrayName.append(Array->name);
-
-    Value *ArraySize = getArraySize(Array);
-    Value *Offset = getArrayOffset(Array);
-    if (Offset)
-      ArraySize = Builder.CreateSub(
-          ArraySize,
-          Builder.CreateMul(Offset,
-                            Builder.getInt64(ScopArray->getElemSizeInBytes())));
-    const SCEV *SizeSCEV = SE.getSCEV(ArraySize);
-    // It makes no sense to have an array of size 0. The CUDA API will
-    // throw an error anyway if we invoke `cuMallocManaged` with size `0`. We
-    // choose to be defensive and catch this at the compile phase. It is
-    // most likely that we are doing something wrong with size computation.
-    if (SizeSCEV->isZero()) {
-      errs() << getUniqueScopName(&S)
-             << " has computed array size 0: " << *ArraySize
-             << " | for array: " << *(ScopArray->getBasePtr())
-             << ". This is illegal, exiting.\n";
-      report_fatal_error("array size was computed to be 0");
-    }
-
-    Value *DevArray = createCallAllocateMemoryForDevice(ArraySize);
-    DevArray->setName(DevArrayName);
-    DeviceAllocations[ScopArray] = DevArray;
-  }
-
-  isl_ast_build_free(Build);
-}
-
-void GPUNodeBuilder::prepareManagedDeviceArrays() {
-  assert(PollyManagedMemory &&
-         "Device array most only be prepared in managed-memory mode");
-  for (int i = 0; i < Prog->n_array; ++i) {
-    gpu_array_info *Array = &Prog->array[i];
-    ScopArrayInfo *ScopArray = (ScopArrayInfo *)Array->user;
-    Value *HostPtr;
-
-    if (gpu_array_is_scalar(Array))
-      HostPtr = BlockGen.getOrCreateAlloca(ScopArray);
-    else
-      HostPtr = ScopArray->getBasePtr();
-    HostPtr = getLatestValue(HostPtr);
-
-    Value *Offset = getArrayOffset(Array);
-    if (Offset) {
-      HostPtr = Builder.CreatePointerCast(
-          HostPtr, ScopArray->getElementType()->getPointerTo());
-      HostPtr = Builder.CreateGEP(ScopArray->getElementType(), HostPtr, Offset);
-    }
-
-    HostPtr = Builder.CreatePointerCast(HostPtr, Builder.getInt8PtrTy());
-    DeviceAllocations[ScopArray] = HostPtr;
-  }
-}
-
-void GPUNodeBuilder::addCUDAAnnotations(Module *M, Value *BlockDimX,
-                                        Value *BlockDimY, Value *BlockDimZ) {
-  auto AnnotationNode = M->getOrInsertNamedMetadata("nvvm.annotations");
-
-  for (auto &F : *M) {
-    if (F.getCallingConv() != CallingConv::PTX_Kernel)
-      continue;
-
-    Value *V[] = {BlockDimX, BlockDimY, BlockDimZ};
-
-    Metadata *Elements[] = {
-        ValueAsMetadata::get(&F),   MDString::get(M->getContext(), "maxntidx"),
-        ValueAsMetadata::get(V[0]), MDString::get(M->getContext(), "maxntidy"),
-        ValueAsMetadata::get(V[1]), MDString::get(M->getContext(), "maxntidz"),
-        ValueAsMetadata::get(V[2]),
-    };
-    MDNode *Node = MDNode::get(M->getContext(), Elements);
-    AnnotationNode->addOperand(Node);
-  }
-}
-
-void GPUNodeBuilder::freeDeviceArrays() {
-  assert(!PollyManagedMemory && "Managed memory does not use device arrays");
-  for (auto &Array : DeviceAllocations)
-    createCallFreeDeviceMemory(Array.second);
-}
-
-Value *GPUNodeBuilder::createCallGetKernel(Value *Buffer, Value *Entry) {
-  const char *Name = "polly_getKernel";
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    std::vector<Type *> Args;
-    Args.push_back(Builder.getInt8PtrTy());
-    Args.push_back(Builder.getInt8PtrTy());
-    FunctionType *Ty = FunctionType::get(Builder.getInt8PtrTy(), Args, false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  return Builder.CreateCall(F, {Buffer, Entry});
-}
-
-Value *GPUNodeBuilder::createCallGetDevicePtr(Value *Allocation) {
-  const char *Name = "polly_getDevicePtr";
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    std::vector<Type *> Args;
-    Args.push_back(Builder.getInt8PtrTy());
-    FunctionType *Ty = FunctionType::get(Builder.getInt8PtrTy(), Args, false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  return Builder.CreateCall(F, {Allocation});
-}
-
-void GPUNodeBuilder::createCallLaunchKernel(Value *GPUKernel, Value *GridDimX,
-                                            Value *GridDimY, Value *BlockDimX,
-                                            Value *BlockDimY, Value *BlockDimZ,
-                                            Value *Parameters) {
-  const char *Name = "polly_launchKernel";
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    std::vector<Type *> Args;
-    Args.push_back(Builder.getInt8PtrTy());
-    Args.push_back(Builder.getInt32Ty());
-    Args.push_back(Builder.getInt32Ty());
-    Args.push_back(Builder.getInt32Ty());
-    Args.push_back(Builder.getInt32Ty());
-    Args.push_back(Builder.getInt32Ty());
-    Args.push_back(Builder.getInt8PtrTy());
-    FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  Builder.CreateCall(F, {GPUKernel, GridDimX, GridDimY, BlockDimX, BlockDimY,
-                         BlockDimZ, Parameters});
-}
-
-void GPUNodeBuilder::createCallFreeKernel(Value *GPUKernel) {
-  const char *Name = "polly_freeKernel";
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    std::vector<Type *> Args;
-    Args.push_back(Builder.getInt8PtrTy());
-    FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  Builder.CreateCall(F, {GPUKernel});
-}
-
-void GPUNodeBuilder::createCallFreeDeviceMemory(Value *Array) {
-  assert(!PollyManagedMemory &&
-         "Managed memory does not allocate or free memory "
-         "for device");
-  const char *Name = "polly_freeDeviceMemory";
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    std::vector<Type *> Args;
-    Args.push_back(Builder.getInt8PtrTy());
-    FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  Builder.CreateCall(F, {Array});
-}
-
-Value *GPUNodeBuilder::createCallAllocateMemoryForDevice(Value *Size) {
-  assert(!PollyManagedMemory &&
-         "Managed memory does not allocate or free memory "
-         "for device");
-  const char *Name = "polly_allocateMemoryForDevice";
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    std::vector<Type *> Args;
-    Args.push_back(Builder.getInt64Ty());
-    FunctionType *Ty = FunctionType::get(Builder.getInt8PtrTy(), Args, false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  return Builder.CreateCall(F, {Size});
-}
-
-void GPUNodeBuilder::createCallCopyFromHostToDevice(Value *HostData,
-                                                    Value *DeviceData,
-                                                    Value *Size) {
-  assert(!PollyManagedMemory &&
-         "Managed memory does not transfer memory between "
-         "device and host");
-  const char *Name = "polly_copyFromHostToDevice";
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    std::vector<Type *> Args;
-    Args.push_back(Builder.getInt8PtrTy());
-    Args.push_back(Builder.getInt8PtrTy());
-    Args.push_back(Builder.getInt64Ty());
-    FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  Builder.CreateCall(F, {HostData, DeviceData, Size});
-}
-
-void GPUNodeBuilder::createCallCopyFromDeviceToHost(Value *DeviceData,
-                                                    Value *HostData,
-                                                    Value *Size) {
-  assert(!PollyManagedMemory &&
-         "Managed memory does not transfer memory between "
-         "device and host");
-  const char *Name = "polly_copyFromDeviceToHost";
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    std::vector<Type *> Args;
-    Args.push_back(Builder.getInt8PtrTy());
-    Args.push_back(Builder.getInt8PtrTy());
-    Args.push_back(Builder.getInt64Ty());
-    FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  Builder.CreateCall(F, {DeviceData, HostData, Size});
-}
-
-void GPUNodeBuilder::createCallSynchronizeDevice() {
-  assert(PollyManagedMemory && "explicit synchronization is only necessary for "
-                               "managed memory");
-  const char *Name = "polly_synchronizeDevice";
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  Builder.CreateCall(F);
-}
-
-Value *GPUNodeBuilder::createCallInitContext() {
-  const char *Name;
-
-  switch (Runtime) {
-  case GPURuntime::CUDA:
-    Name = "polly_initContextCUDA";
-    break;
-  case GPURuntime::OpenCL:
-    Name = "polly_initContextCL";
-    break;
-  }
-
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    std::vector<Type *> Args;
-    FunctionType *Ty = FunctionType::get(Builder.getInt8PtrTy(), Args, false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  return Builder.CreateCall(F, {});
-}
-
-void GPUNodeBuilder::createCallFreeContext(Value *Context) {
-  const char *Name = "polly_freeContext";
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  Function *F = M->getFunction(Name);
-
-  // If F is not available, declare it.
-  if (!F) {
-    GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-    std::vector<Type *> Args;
-    Args.push_back(Builder.getInt8PtrTy());
-    FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
-    F = Function::Create(Ty, Linkage, Name, M);
-  }
-
-  Builder.CreateCall(F, {Context});
-}
-
-/// Check if one string is a prefix of another.
-///
-/// @param String The string in which to look for the prefix.
-/// @param Prefix The prefix to look for.
-static bool isPrefix(std::string String, std::string Prefix) {
-  return String.find(Prefix) == 0;
-}
-
-Value *GPUNodeBuilder::getArraySize(gpu_array_info *Array) {
-  isl::ast_build Build = isl::ast_build::from_context(S.getContext());
-  Value *ArraySize = ConstantInt::get(Builder.getInt64Ty(), Array->size);
-
-  if (!gpu_array_is_scalar(Array)) {
-    isl::multi_pw_aff ArrayBound = isl::manage_copy(Array->bound);
-
-    isl::pw_aff OffsetDimZero = ArrayBound.at(0);
-    isl::ast_expr Res = Build.expr_from(OffsetDimZero);
-
-    for (unsigned int i = 1; i < Array->n_index; i++) {
-      isl::pw_aff Bound_I = ArrayBound.at(i);
-      isl::ast_expr Expr = Build.expr_from(Bound_I);
-      Res = Res.mul(Expr);
-    }
-
-    Value *NumElements = ExprBuilder.create(Res.release());
-    if (NumElements->getType() != ArraySize->getType())
-      NumElements = Builder.CreateSExt(NumElements, ArraySize->getType());
-    ArraySize = Builder.CreateMul(ArraySize, NumElements);
-  }
-  return ArraySize;
-}
-
-Value *GPUNodeBuilder::getArrayOffset(gpu_array_info *Array) {
-  if (gpu_array_is_scalar(Array))
-    return nullptr;
-
-  isl::ast_build Build = isl::ast_build::from_context(S.getContext());
-
-  isl::set Min = isl::manage_copy(Array->extent).lexmin();
-
-  isl::set ZeroSet = isl::set::universe(Min.get_space());
-
-  for (unsigned i : rangeIslSize(0, Min.tuple_dim()))
-    ZeroSet = ZeroSet.fix_si(isl::dim::set, i, 0);
-
-  if (Min.is_subset(ZeroSet)) {
-    return nullptr;
-  }
-
-  isl::ast_expr Result = isl::ast_expr::from_val(isl::val(Min.ctx(), 0));
-
-  for (unsigned i : rangeIslSize(0, Min.tuple_dim())) {
-    if (i > 0) {
-      isl::pw_aff Bound_I =
-          isl::manage(isl_multi_pw_aff_get_pw_aff(Array->bound, i - 1));
-      isl::ast_expr BExpr = Build.expr_from(Bound_I);
-      Result = Result.mul(BExpr);
-    }
-    isl::pw_aff DimMin = Min.dim_min(i);
-    isl::ast_expr MExpr = Build.expr_from(DimMin);
-    Result = Result.add(MExpr);
-  }
-
-  return ExprBuilder.create(Result.release());
-}
-
-Value *GPUNodeBuilder::getManagedDeviceArray(gpu_array_info *Array,
-                                             ScopArrayInfo *ArrayInfo) {
-  assert(PollyManagedMemory && "Only used when you wish to get a host "
-                               "pointer for sending data to the kernel, "
-                               "with managed memory");
-  std::map<ScopArrayInfo *, Value *>::iterator it;
-  it = DeviceAllocations.find(ArrayInfo);
-  assert(it != DeviceAllocations.end() &&
-         "Device array expected to be available");
-  return it->second;
-}
-
-void GPUNodeBuilder::createDataTransfer(__isl_take isl_ast_node *TransferStmt,
-                                        enum DataDirection Direction) {
-  assert(!PollyManagedMemory && "Managed memory needs no data transfers");
-  isl_ast_expr *Expr = isl_ast_node_user_get_expr(TransferStmt);
-  isl_ast_expr *Arg = isl_ast_expr_get_op_arg(Expr, 0);
-  isl_id *Id = isl_ast_expr_get_id(Arg);
-  auto Array = (gpu_array_info *)isl_id_get_user(Id);
-  auto ScopArray = (ScopArrayInfo *)(Array->user);
-
-  Value *Size = getArraySize(Array);
-  Value *Offset = getArrayOffset(Array);
-  Value *DevPtr = DeviceAllocations[ScopArray];
-
-  Value *HostPtr;
-
-  if (gpu_array_is_scalar(Array))
-    HostPtr = BlockGen.getOrCreateAlloca(ScopArray);
-  else
-    HostPtr = ScopArray->getBasePtr();
-  HostPtr = getLatestValue(HostPtr);
-
-  if (Offset) {
-    HostPtr = Builder.CreatePointerCast(
-        HostPtr, ScopArray->getElementType()->getPointerTo());
-    HostPtr = Builder.CreateGEP(ScopArray->getElementType(), HostPtr, Offset);
-  }
-
-  HostPtr = Builder.CreatePointerCast(HostPtr, Builder.getInt8PtrTy());
-
-  if (Offset) {
-    Size = Builder.CreateSub(
-        Size, Builder.CreateMul(
-                  Offset, Builder.getInt64(ScopArray->getElemSizeInBytes())));
-  }
-
-  if (Direction == HOST_TO_DEVICE)
-    createCallCopyFromHostToDevice(HostPtr, DevPtr, Size);
-  else
-    createCallCopyFromDeviceToHost(DevPtr, HostPtr, Size);
-
-  isl_id_free(Id);
-  isl_ast_expr_free(Arg);
-  isl_ast_expr_free(Expr);
-  isl_ast_node_free(TransferStmt);
-}
-
-void GPUNodeBuilder::createUser(__isl_take isl_ast_node *UserStmt) {
-  isl_ast_expr *Expr = isl_ast_node_user_get_expr(UserStmt);
-  isl_ast_expr *StmtExpr = isl_ast_expr_get_op_arg(Expr, 0);
-  isl_id *Id = isl_ast_expr_get_id(StmtExpr);
-  isl_id_free(Id);
-  isl_ast_expr_free(StmtExpr);
-
-  const char *Str = isl_id_get_name(Id);
-  if (!strcmp(Str, "kernel")) {
-    createKernel(UserStmt);
-    if (PollyManagedMemory)
-      createCallSynchronizeDevice();
-    isl_ast_expr_free(Expr);
-    return;
-  }
-  if (!strcmp(Str, "init_device")) {
-    initializeAfterRTH();
-    isl_ast_node_free(UserStmt);
-    isl_ast_expr_free(Expr);
-    return;
-  }
-  if (!strcmp(Str, "clear_device")) {
-    finalize();
-    isl_ast_node_free(UserStmt);
-    isl_ast_expr_free(Expr);
-    return;
-  }
-  if (isPrefix(Str, "to_device")) {
-    if (!PollyManagedMemory)
-      createDataTransfer(UserStmt, HOST_TO_DEVICE);
-    else
-      isl_ast_node_free(UserStmt);
-
-    isl_ast_expr_free(Expr);
-    return;
-  }
-
-  if (isPrefix(Str, "from_device")) {
-    if (!PollyManagedMemory) {
-      createDataTransfer(UserStmt, DEVICE_TO_HOST);
-    } else {
-      isl_ast_node_free(UserStmt);
-    }
-    isl_ast_expr_free(Expr);
-    return;
-  }
-
-  isl_id *Anno = isl_ast_node_get_annotation(UserStmt);
-  struct ppcg_kernel_stmt *KernelStmt =
-      (struct ppcg_kernel_stmt *)isl_id_get_user(Anno);
-  isl_id_free(Anno);
-
-  switch (KernelStmt->type) {
-  case ppcg_kernel_domain:
-    createScopStmt(Expr, KernelStmt);
-    isl_ast_node_free(UserStmt);
-    return;
-  case ppcg_kernel_copy:
-    createKernelCopy(KernelStmt);
-    isl_ast_expr_free(Expr);
-    isl_ast_node_free(UserStmt);
-    return;
-  case ppcg_kernel_sync:
-    createKernelSync();
-    isl_ast_expr_free(Expr);
-    isl_ast_node_free(UserStmt);
-    return;
-  }
-
-  isl_ast_expr_free(Expr);
-  isl_ast_node_free(UserStmt);
-}
-
-void GPUNodeBuilder::createFor(__isl_take isl_ast_node *Node) {
-  createForSequential(isl::manage(Node).as<isl::ast_node_for>(), false);
-}
-
-void GPUNodeBuilder::createKernelCopy(ppcg_kernel_stmt *KernelStmt) {
-  isl_ast_expr *LocalIndex = isl_ast_expr_copy(KernelStmt->u.c.local_index);
-  auto LocalAddr = ExprBuilder.createAccessAddress(LocalIndex);
-  isl_ast_expr *Index = isl_ast_expr_copy(KernelStmt->u.c.index);
-  auto GlobalAddr = ExprBuilder.createAccessAddress(Index);
-
-  if (KernelStmt->u.c.read) {
-    LoadInst *Load =
-        Builder.CreateLoad(GlobalAddr.second, GlobalAddr.first, "shared.read");
-    Builder.CreateStore(Load, LocalAddr.first);
-  } else {
-    LoadInst *Load =
-        Builder.CreateLoad(LocalAddr.second, LocalAddr.first, "shared.write");
-    Builder.CreateStore(Load, GlobalAddr.first);
-  }
-}
-
-void GPUNodeBuilder::createScopStmt(isl_ast_expr *Expr,
-                                    ppcg_kernel_stmt *KernelStmt) {
-  auto Stmt = (ScopStmt *)KernelStmt->u.d.stmt->stmt;
-  isl_id_to_ast_expr *Indexes = KernelStmt->u.d.ref2expr;
-
-  LoopToScevMapT LTS;
-  LTS.insert(OutsideLoopIterations.begin(), OutsideLoopIterations.end());
-
-  createSubstitutions(Expr, Stmt, LTS);
-
-  if (Stmt->isBlockStmt())
-    BlockGen.copyStmt(*Stmt, LTS, Indexes);
-  else
-    RegionGen.copyStmt(*Stmt, LTS, Indexes);
-}
-
-void GPUNodeBuilder::createKernelSync() {
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-  const char *SpirName = "__gen_ocl_barrier_global";
-
-  Function *Sync;
-
-  switch (Arch) {
-  case GPUArch::SPIR64:
-  case GPUArch::SPIR32:
-    Sync = M->getFunction(SpirName);
-
-    // If Sync is not available, declare it.
-    if (!Sync) {
-      GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-      std::vector<Type *> Args;
-      FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
-      Sync = Function::Create(Ty, Linkage, SpirName, M);
-      Sync->setCallingConv(CallingConv::SPIR_FUNC);
-    }
-    break;
-  case GPUArch::NVPTX64:
-    Sync = Intrinsic::getDeclaration(M, Intrinsic::nvvm_barrier0);
-    break;
-  }
-
-  Builder.CreateCall(Sync, {});
-}
-
-/// Collect llvm::Values referenced from @p Node
-///
-/// This function only applies to isl_ast_nodes that are user_nodes referring
-/// to a ScopStmt. All other node types are ignore.
-///
-/// @param Node The node to collect references for.
-/// @param User A user pointer used as storage for the data that is collected.
-///
-/// @returns isl_bool_true if data could be collected successfully.
-isl_bool collectReferencesInGPUStmt(__isl_keep isl_ast_node *Node, void *User) {
-  if (isl_ast_node_get_type(Node) != isl_ast_node_user)
-    return isl_bool_true;
-
-  isl_ast_expr *Expr = isl_ast_node_user_get_expr(Node);
-  isl_ast_expr *StmtExpr = isl_ast_expr_get_op_arg(Expr, 0);
-  isl_id *Id = isl_ast_expr_get_id(StmtExpr);
-  const char *Str = isl_id_get_name(Id);
-  isl_id_free(Id);
-  isl_ast_expr_free(StmtExpr);
-  isl_ast_expr_free(Expr);
-
-  if (!isPrefix(Str, "Stmt"))
-    return isl_bool_true;
-
-  Id = isl_ast_node_get_annotation(Node);
-  auto *KernelStmt = (ppcg_kernel_stmt *)isl_id_get_user(Id);
-  auto Stmt = (ScopStmt *)KernelStmt->u.d.stmt->stmt;
-  isl_id_free(Id);
-
-  addReferencesFromStmt(Stmt, User, false /* CreateScalarRefs */);
-
-  return isl_bool_true;
-}
-
-/// A list of functions that are available in NVIDIA's libdevice.
-const std::set<std::string> CUDALibDeviceFunctions = {
-    "exp",      "expf",      "expl",      "cos", "cosf", "sqrt", "sqrtf",
-    "copysign", "copysignf", "copysignl", "log", "logf", "powi", "powif"};
-
-// A map from intrinsics to their corresponding libdevice functions.
-const std::map<std::string, std::string> IntrinsicToLibdeviceFunc = {
-    {"llvm.exp.f64", "exp"},
-    {"llvm.exp.f32", "expf"},
-    {"llvm.powi.f64.i32", "powi"},
-    {"llvm.powi.f32.i32", "powif"}};
-
-/// Return the corresponding CUDA libdevice function name @p Name.
-/// Note that this function will try to convert instrinsics in the list
-/// IntrinsicToLibdeviceFunc into libdevice functions.
-/// This is because some intrinsics such as `exp`
-/// are not supported by the NVPTX backend.
-/// If this restriction of the backend is lifted, we should refactor our code
-/// so that we use intrinsics whenever possible.
-///
-/// Return "" if we are not compiling for CUDA.
-std::string getCUDALibDeviceFuntion(StringRef NameRef) {
-  std::string Name = NameRef.str();
-  auto It = IntrinsicToLibdeviceFunc.find(Name);
-  if (It != IntrinsicToLibdeviceFunc.end())
-    return getCUDALibDeviceFuntion(It->second);
-
-  if (CUDALibDeviceFunctions.count(Name))
-    return ("__nv_" + Name);
-
-  return "";
-}
-
-/// Check if F is a function that we can code-generate in a GPU kernel.
-static bool isValidFunctionInKernel(llvm::Function *F, bool AllowLibDevice) {
-  assert(F && "F is an invalid pointer");
-  // We string compare against the name of the function to allow
-  // all variants of the intrinsic "llvm.sqrt.*", "llvm.fabs", and
-  // "llvm.copysign".
-  const StringRef Name = F->getName();
-
-  if (AllowLibDevice && getCUDALibDeviceFuntion(Name).length() > 0)
-    return true;
-
-  return F->isIntrinsic() &&
-         (Name.startswith("llvm.sqrt") || Name.startswith("llvm.fabs") ||
-          Name.startswith("llvm.copysign"));
-}
-
-/// Do not take `Function` as a subtree value.
-///
-/// We try to take the reference of all subtree values and pass them along
-/// to the kernel from the host. Taking an address of any function and
-/// trying to pass along is nonsensical. Only allow `Value`s that are not
-/// `Function`s.
-static bool isValidSubtreeValue(llvm::Value *V) { return !isa<Function>(V); }
-
-/// Return `Function`s from `RawSubtreeValues`.
-static SetVector<Function *>
-getFunctionsFromRawSubtreeValues(SetVector<Value *> RawSubtreeValues,
-                                 bool AllowCUDALibDevice) {
-  SetVector<Function *> SubtreeFunctions;
-  for (Value *It : RawSubtreeValues) {
-    Function *F = dyn_cast<Function>(It);
-    if (F) {
-      assert(isValidFunctionInKernel(F, AllowCUDALibDevice) &&
-             "Code should have bailed out by "
-             "this point if an invalid function "
-             "were present in a kernel.");
-      SubtreeFunctions.insert(F);
-    }
-  }
-  return SubtreeFunctions;
-}
-
-std::tuple<SetVector<Value *>, SetVector<Function *>, SetVector<const Loop *>,
-           isl::space>
-GPUNodeBuilder::getReferencesInKernel(ppcg_kernel *Kernel) {
-  SetVector<Value *> SubtreeValues;
-  SetVector<const SCEV *> SCEVs;
-  SetVector<const Loop *> Loops;
-  isl::space ParamSpace = isl::space(S.getIslCtx(), 0, 0).params();
-  SubtreeReferences References = {
-      LI,         SE, S, ValueMap, SubtreeValues, SCEVs, getBlockGenerator(),
-      &ParamSpace};
-
-  for (const auto &I : IDToValue)
-    SubtreeValues.insert(I.second);
-
-  // NOTE: this is populated in IslNodeBuilder::addParameters
-  // See [Code generation of induction variables of loops outside Scops].
-  for (const auto &I : OutsideLoopIterations)
-    SubtreeValues.insert(cast<SCEVUnknown>(I.second)->getValue());
-
-  isl_ast_node_foreach_descendant_top_down(
-      Kernel->tree, collectReferencesInGPUStmt, &References);
-
-  for (const SCEV *Expr : SCEVs) {
-    findValues(Expr, SE, SubtreeValues);
-    findLoops(Expr, Loops);
-  }
-
-  Loops.remove_if([this](const Loop *L) {
-    return S.contains(L) || L->contains(S.getEntry());
-  });
-
-  for (auto &SAI : S.arrays())
-    SubtreeValues.remove(SAI->getBasePtr());
-
-  isl_space *Space = S.getParamSpace().release();
-  for (long i = 0, n = isl_space_dim(Space, isl_dim_param); i < n; i++) {
-    isl_id *Id = isl_space_get_dim_id(Space, isl_dim_param, i);
-    assert(IDToValue.count(Id));
-    Value *Val = IDToValue[Id];
-    SubtreeValues.remove(Val);
-    isl_id_free(Id);
-  }
-  isl_space_free(Space);
-
-  for (long i = 0, n = isl_space_dim(Kernel->space, isl_dim_set); i < n; i++) {
-    isl_id *Id = isl_space_get_dim_id(Kernel->space, isl_dim_set, i);
-    assert(IDToValue.count(Id));
-    Value *Val = IDToValue[Id];
-    SubtreeValues.remove(Val);
-    isl_id_free(Id);
-  }
-
-  // Note: { ValidSubtreeValues, ValidSubtreeFunctions } partitions
-  // SubtreeValues. This is important, because we should not lose any
-  // SubtreeValues in the process of constructing the
-  // "ValidSubtree{Values, Functions} sets. Nor should the set
-  // ValidSubtree{Values, Functions} have any common element.
-  auto ValidSubtreeValuesIt =
-      make_filter_range(SubtreeValues, isValidSubtreeValue);
-  SetVector<Value *> ValidSubtreeValues(ValidSubtreeValuesIt.begin(),
-                                        ValidSubtreeValuesIt.end());
-
-  bool AllowCUDALibDevice = Arch == GPUArch::NVPTX64;
-
-  SetVector<Function *> ValidSubtreeFunctions(
-      getFunctionsFromRawSubtreeValues(SubtreeValues, AllowCUDALibDevice));
-
-  // @see IslNodeBuilder::getReferencesInSubtree
-  SetVector<Value *> ReplacedValues;
-  for (Value *V : ValidSubtreeValues) {
-    auto It = ValueMap.find(V);
-    if (It == ValueMap.end())
-      ReplacedValues.insert(V);
-    else
-      ReplacedValues.insert(It->second);
-  }
-  return std::make_tuple(ReplacedValues, ValidSubtreeFunctions, Loops,
-                         ParamSpace);
-}
-
-void GPUNodeBuilder::clearDominators(Function *F) {
-  DomTreeNode *N = DT.getNode(&F->getEntryBlock());
-  std::vector<BasicBlock *> Nodes;
-  for (po_iterator<DomTreeNode *> I = po_begin(N), E = po_end(N); I != E; ++I)
-    Nodes.push_back(I->getBlock());
-
-  for (BasicBlock *BB : Nodes)
-    DT.eraseNode(BB);
-}
-
-void GPUNodeBuilder::clearScalarEvolution(Function *F) {
-  for (BasicBlock &BB : *F) {
-    Loop *L = LI.getLoopFor(&BB);
-    if (L)
-      SE.forgetLoop(L);
-  }
-}
-
-void GPUNodeBuilder::clearLoops(Function *F) {
-  SmallSet<Loop *, 1> WorkList;
-  for (BasicBlock &BB : *F) {
-    Loop *L = LI.getLoopFor(&BB);
-    if (L)
-      WorkList.insert(L);
-  }
-  for (auto *L : WorkList)
-    LI.erase(L);
-}
-
-std::tuple<Value *, Value *> GPUNodeBuilder::getGridSizes(ppcg_kernel *Kernel) {
-  std::vector<Value *> Sizes;
-  isl::ast_build Context = isl::ast_build::from_context(S.getContext());
-
-  isl::multi_pw_aff GridSizePwAffs = isl::manage_copy(Kernel->grid_size);
-  for (long i = 0; i < Kernel->n_grid; i++) {
-    isl::pw_aff Size = GridSizePwAffs.at(i);
-    isl::ast_expr GridSize = Context.expr_from(Size);
-    Value *Res = ExprBuilder.create(GridSize.release());
-    Res = Builder.CreateTrunc(Res, Builder.getInt32Ty());
-    Sizes.push_back(Res);
-  }
-
-  for (long i = Kernel->n_grid; i < 3; i++)
-    Sizes.push_back(ConstantInt::get(Builder.getInt32Ty(), 1));
-
-  return std::make_tuple(Sizes[0], Sizes[1]);
-}
-
-std::tuple<Value *, Value *, Value *>
-GPUNodeBuilder::getBlockSizes(ppcg_kernel *Kernel) {
-  std::vector<Value *> Sizes;
-
-  for (long i = 0; i < Kernel->n_block; i++) {
-    Value *Res = ConstantInt::get(Builder.getInt32Ty(), Kernel->block_dim[i]);
-    Sizes.push_back(Res);
-  }
-
-  for (long i = Kernel->n_block; i < 3; i++)
-    Sizes.push_back(ConstantInt::get(Builder.getInt32Ty(), 1));
-
-  return std::make_tuple(Sizes[0], Sizes[1], Sizes[2]);
-}
-
-void GPUNodeBuilder::insertStoreParameter(Type *ArrayTy,
-                                          Instruction *Parameters,
-                                          Instruction *Param, int Index) {
-  Value *Slot = Builder.CreateGEP(
-      ArrayTy, Parameters, {Builder.getInt64(0), Builder.getInt64(Index)});
-  Value *ParamTyped = Builder.CreatePointerCast(Param, Builder.getInt8PtrTy());
-  Builder.CreateStore(ParamTyped, Slot);
-}
-
-Value *
-GPUNodeBuilder::createLaunchParameters(ppcg_kernel *Kernel, Function *F,
-                                       SetVector<Value *> SubtreeValues) {
-  const int NumArgs = F->arg_size();
-  std::vector<int> ArgSizes(NumArgs);
-
-  // If we are using the OpenCL Runtime, we need to add the kernel argument
-  // sizes to the end of the launch-parameter list, so OpenCL can determine
-  // how big the respective kernel arguments are.
-  // Here we need to reserve adequate space for that.
-  Type *ArrayTy;
-  if (Runtime == GPURuntime::OpenCL)
-    ArrayTy = ArrayType::get(Builder.getInt8PtrTy(), 2 * NumArgs);
-  else
-    ArrayTy = ArrayType::get(Builder.getInt8PtrTy(), NumArgs);
-
-  BasicBlock *EntryBlock =
-      &Builder.GetInsertBlock()->getParent()->getEntryBlock();
-  auto AddressSpace = F->getParent()->getDataLayout().getAllocaAddrSpace();
-  std::string Launch = "polly_launch_" + std::to_string(Kernel->id);
-  Instruction *Parameters = new AllocaInst(
-      ArrayTy, AddressSpace, Launch + "_params", EntryBlock->getTerminator());
-
-  int Index = 0;
-  for (long i = 0; i < Prog->n_array; i++) {
-    if (!ppcg_kernel_requires_array_argument(Kernel, i))
-      continue;
-
-    isl_id *Id = isl_space_get_tuple_id(Prog->array[i].space, isl_dim_set);
-    const ScopArrayInfo *SAI = ScopArrayInfo::getFromId(isl::manage(Id));
-
-    if (Runtime == GPURuntime::OpenCL)
-      ArgSizes[Index] = SAI->getElemSizeInBytes();
-
-    Value *DevArray = nullptr;
-    if (PollyManagedMemory) {
-      DevArray = getManagedDeviceArray(&Prog->array[i],
-                                       const_cast<ScopArrayInfo *>(SAI));
-    } else {
-      DevArray = DeviceAllocations[const_cast<ScopArrayInfo *>(SAI)];
-      DevArray = createCallGetDevicePtr(DevArray);
-    }
-    assert(DevArray != nullptr && "Array to be offloaded to device not "
-                                  "initialized");
-    Value *Offset = getArrayOffset(&Prog->array[i]);
-
-    if (Offset) {
-      DevArray = Builder.CreatePointerCast(
-          DevArray, SAI->getElementType()->getPointerTo());
-      DevArray = Builder.CreateGEP(SAI->getElementType(), DevArray,
-                                   Builder.CreateNeg(Offset));
-      DevArray = Builder.CreatePointerCast(DevArray, Builder.getInt8PtrTy());
-    }
-    Value *Slot = Builder.CreateGEP(
-        ArrayTy, Parameters, {Builder.getInt64(0), Builder.getInt64(Index)});
-
-    if (gpu_array_is_read_only_scalar(&Prog->array[i])) {
-      Value *ValPtr = nullptr;
-      if (PollyManagedMemory)
-        ValPtr = DevArray;
-      else
-        ValPtr = BlockGen.getOrCreateAlloca(SAI);
-
-      assert(ValPtr != nullptr && "ValPtr that should point to a valid object"
-                                  " to be stored into Parameters");
-      Value *ValPtrCast =
-          Builder.CreatePointerCast(ValPtr, Builder.getInt8PtrTy());
-      Builder.CreateStore(ValPtrCast, Slot);
-    } else {
-      Instruction *Param =
-          new AllocaInst(Builder.getInt8PtrTy(), AddressSpace,
-                         Launch + "_param_" + std::to_string(Index),
-                         EntryBlock->getTerminator());
-      Builder.CreateStore(DevArray, Param);
-      Value *ParamTyped =
-          Builder.CreatePointerCast(Param, Builder.getInt8PtrTy());
-      Builder.CreateStore(ParamTyped, Slot);
-    }
-    Index++;
-  }
-
-  int NumHostIters = isl_space_dim(Kernel->space, isl_dim_set);
-
-  for (long i = 0; i < NumHostIters; i++) {
-    isl_id *Id = isl_space_get_dim_id(Kernel->space, isl_dim_set, i);
-    Value *Val = IDToValue[Id];
-    isl_id_free(Id);
-
-    if (Runtime == GPURuntime::OpenCL)
-      ArgSizes[Index] = computeSizeInBytes(Val->getType());
-
-    Instruction *Param =
-        new AllocaInst(Val->getType(), AddressSpace,
-                       Launch + "_param_" + std::to_string(Index),
-                       EntryBlock->getTerminator());
-    Builder.CreateStore(Val, Param);
-    insertStoreParameter(ArrayTy, Parameters, Param, Index);
-    Index++;
-  }
-
-  int NumVars = isl_space_dim(Kernel->space, isl_dim_param);
-
-  for (long i = 0; i < NumVars; i++) {
-    isl_id *Id = isl_space_get_dim_id(Kernel->space, isl_dim_param, i);
-    Value *Val = IDToValue[Id];
-    if (ValueMap.count(Val))
-      Val = ValueMap[Val];
-    isl_id_free(Id);
-
-    if (Runtime == GPURuntime::OpenCL)
-      ArgSizes[Index] = computeSizeInBytes(Val->getType());
-
-    Instruction *Param =
-        new AllocaInst(Val->getType(), AddressSpace,
-                       Launch + "_param_" + std::to_string(Index),
-                       EntryBlock->getTerminator());
-    Builder.CreateStore(Val, Param);
-    insertStoreParameter(ArrayTy, Parameters, Param, Index);
-    Index++;
-  }
-
-  for (auto Val : SubtreeValues) {
-    if (Runtime == GPURuntime::OpenCL)
-      ArgSizes[Index] = computeSizeInBytes(Val->getType());
-
-    Instruction *Param =
-        new AllocaInst(Val->getType(), AddressSpace,
-                       Launch + "_param_" + std::to_string(Index),
-                       EntryBlock->getTerminator());
-    Builder.CreateStore(Val, Param);
-    insertStoreParameter(ArrayTy, Parameters, Param, Index);
-    Index++;
-  }
-
-  if (Runtime == GPURuntime::OpenCL) {
-    for (int i = 0; i < NumArgs; i++) {
-      Value *Val = ConstantInt::get(Builder.getInt32Ty(), ArgSizes[i]);
-      Instruction *Param =
-          new AllocaInst(Builder.getInt32Ty(), AddressSpace,
-                         Launch + "_param_size_" + std::to_string(i),
-                         EntryBlock->getTerminator());
-      Builder.CreateStore(Val, Param);
-      insertStoreParameter(ArrayTy, Parameters, Param, Index);
-      Index++;
-    }
-  }
-
-  auto Location = EntryBlock->getTerminator();
-  return new BitCastInst(Parameters, Builder.getInt8PtrTy(),
-                         Launch + "_params_i8ptr", Location);
-}
-
-void GPUNodeBuilder::setupKernelSubtreeFunctions(
-    SetVector<Function *> SubtreeFunctions) {
-  for (auto Fn : SubtreeFunctions) {
-    const std::string ClonedFnName = Fn->getName().str();
-    Function *Clone = GPUModule->getFunction(ClonedFnName);
-    if (!Clone)
-      Clone =
-          Function::Create(Fn->getFunctionType(), GlobalValue::ExternalLinkage,
-                           ClonedFnName, GPUModule.get());
-    assert(Clone && "Expected cloned function to be initialized.");
-    assert(ValueMap.find(Fn) == ValueMap.end() &&
-           "Fn already present in ValueMap");
-    ValueMap[Fn] = Clone;
-  }
-}
-void GPUNodeBuilder::createKernel(__isl_take isl_ast_node *KernelStmt) {
-  isl_id *Id = isl_ast_node_get_annotation(KernelStmt);
-  ppcg_kernel *Kernel = (ppcg_kernel *)isl_id_get_user(Id);
-  isl_id_free(Id);
-  isl_ast_node_free(KernelStmt);
-
-  if (Kernel->n_grid > 1)
-    DeepestParallel = std::max(
-        DeepestParallel, (unsigned)isl_space_dim(Kernel->space, isl_dim_set));
-  else
-    DeepestSequential = std::max(
-        DeepestSequential, (unsigned)isl_space_dim(Kernel->space, isl_dim_set));
-
-  Value *BlockDimX, *BlockDimY, *BlockDimZ;
-  std::tie(BlockDimX, BlockDimY, BlockDimZ) = getBlockSizes(Kernel);
-
-  SetVector<Value *> SubtreeValues;
-  SetVector<Function *> SubtreeFunctions;
-  SetVector<const Loop *> Loops;
-  isl::space ParamSpace;
-  std::tie(SubtreeValues, SubtreeFunctions, Loops, ParamSpace) =
-      getReferencesInKernel(Kernel);
-
-  // Add parameters that appear only in the access function to the kernel
-  // space. This is important to make sure that all isl_ids are passed as
-  // parameters to the kernel, even though we may not have all parameters
-  // in the context to improve compile time.
-  Kernel->space = isl_space_align_params(Kernel->space, ParamSpace.release());
-
-  assert(Kernel->tree && "Device AST of kernel node is empty");
-
-  Instruction &HostInsertPoint = *Builder.GetInsertPoint();
-  IslExprBuilder::IDToValueTy HostIDs = IDToValue;
-  ValueMapT HostValueMap = ValueMap;
-  BlockGenerator::AllocaMapTy HostScalarMap = ScalarMap;
-  ScalarMap.clear();
-  BlockGenerator::EscapeUsersAllocaMapTy HostEscapeMap = EscapeMap;
-  EscapeMap.clear();
-
-  // Create for all loops we depend on values that contain the current loop
-  // iteration. These values are necessary to generate code for SCEVs that
-  // depend on such loops. As a result we need to pass them to the subfunction.
-  for (const Loop *L : Loops) {
-    const SCEV *OuterLIV = SE.getAddRecExpr(SE.getUnknown(Builder.getInt64(0)),
-                                            SE.getUnknown(Builder.getInt64(1)),
-                                            L, SCEV::FlagAnyWrap);
-    Value *V = generateSCEV(OuterLIV);
-    OutsideLoopIterations[L] = SE.getUnknown(V);
-    SubtreeValues.insert(V);
-  }
-
-  createKernelFunction(Kernel, SubtreeValues, SubtreeFunctions);
-  setupKernelSubtreeFunctions(SubtreeFunctions);
-
-  create(isl_ast_node_copy(Kernel->tree));
-
-  finalizeKernelArguments(Kernel);
-  Function *F = Builder.GetInsertBlock()->getParent();
-  if (Arch == GPUArch::NVPTX64)
-    addCUDAAnnotations(F->getParent(), BlockDimX, BlockDimY, BlockDimZ);
-  clearDominators(F);
-  clearScalarEvolution(F);
-  clearLoops(F);
-
-  IDToValue = HostIDs;
-
-  ValueMap = std::move(HostValueMap);
-  ScalarMap = std::move(HostScalarMap);
-  EscapeMap = std::move(HostEscapeMap);
-  IDToSAI.clear();
-  Annotator.resetAlternativeAliasBases();
-  for (auto &BasePtr : LocalArrays)
-    S.invalidateScopArrayInfo(BasePtr, MemoryKind::Array);
-  LocalArrays.clear();
-
-  std::string ASMString = finalizeKernelFunction();
-  Builder.SetInsertPoint(&HostInsertPoint);
-  Value *Parameters = createLaunchParameters(Kernel, F, SubtreeValues);
-
-  std::string Name = getKernelFuncName(Kernel->id);
-  Value *KernelString = Builder.CreateGlobalStringPtr(ASMString, Name);
-  Value *NameString = Builder.CreateGlobalStringPtr(Name, Name + "_name");
-  Value *GPUKernel = createCallGetKernel(KernelString, NameString);
-
-  Value *GridDimX, *GridDimY;
-  std::tie(GridDimX, GridDimY) = getGridSizes(Kernel);
-
-  createCallLaunchKernel(GPUKernel, GridDimX, GridDimY, BlockDimX, BlockDimY,
-                         BlockDimZ, Parameters);
-  createCallFreeKernel(GPUKernel);
-
-  for (auto Id : KernelIds)
-    isl_id_free(Id);
-
-  KernelIds.clear();
-}
-
-/// Compute the DataLayout string for the NVPTX backend.
-///
-/// @param is64Bit Are we looking for a 64 bit architecture?
-static std::string computeNVPTXDataLayout(bool is64Bit) {
-  std::string Ret = "";
-
-  if (!is64Bit) {
-    Ret += "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:"
-           "64-i128:128:128-f32:32:32-f64:64:64-v16:16:16-v32:32:32-v64:64:"
-           "64-v128:128:128-n16:32:64";
-  } else {
-    Ret += "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:"
-           "64-i128:128:128-f32:32:32-f64:64:64-v16:16:16-v32:32:32-v64:64:"
-           "64-v128:128:128-n16:32:64";
-  }
-
-  return Ret;
-}
-
-/// Compute the DataLayout string for a SPIR kernel.
-///
-/// @param is64Bit Are we looking for a 64 bit architecture?
-static std::string computeSPIRDataLayout(bool is64Bit) {
-  std::string Ret = "";
-
-  if (!is64Bit) {
-    Ret += "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:"
-           "64-i128:128:128-f32:32:32-f64:64:64-v16:16:16-v24:32:32-v32:32:"
-           "32-v48:64:64-v64:64:64-v96:128:128-v128:128:128-v192:"
-           "256:256-v256:256:256-v512:512:512-v1024:1024:1024";
-  } else {
-    Ret += "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:"
-           "64-i128:128:128-f32:32:32-f64:64:64-v16:16:16-v24:32:32-v32:32:"
-           "32-v48:64:64-v64:64:64-v96:128:128-v128:128:128-v192:"
-           "256:256-v256:256:256-v512:512:512-v1024:1024:1024";
-  }
-
-  return Ret;
-}
-
-Function *
-GPUNodeBuilder::createKernelFunctionDecl(ppcg_kernel *Kernel,
-                                         SetVector<Value *> &SubtreeValues) {
-  std::vector<Type *> Args;
-  std::string Identifier = getKernelFuncName(Kernel->id);
-
-  std::vector<Metadata *> MemoryType;
-
-  for (long i = 0; i < Prog->n_array; i++) {
-    if (!ppcg_kernel_requires_array_argument(Kernel, i))
-      continue;
-
-    if (gpu_array_is_read_only_scalar(&Prog->array[i])) {
-      isl_id *Id = isl_space_get_tuple_id(Prog->array[i].space, isl_dim_set);
-      const ScopArrayInfo *SAI = ScopArrayInfo::getFromId(isl::manage(Id));
-      Args.push_back(SAI->getElementType());
-      MemoryType.push_back(
-          ConstantAsMetadata::get(ConstantInt::get(Builder.getInt32Ty(), 0)));
-    } else {
-      static const int UseGlobalMemory = 1;
-      Args.push_back(Builder.getInt8PtrTy(UseGlobalMemory));
-      MemoryType.push_back(
-          ConstantAsMetadata::get(ConstantInt::get(Builder.getInt32Ty(), 1)));
-    }
-  }
-
-  int NumHostIters = isl_space_dim(Kernel->space, isl_dim_set);
-
-  for (long i = 0; i < NumHostIters; i++) {
-    Args.push_back(Builder.getInt64Ty());
-    MemoryType.push_back(
-        ConstantAsMetadata::get(ConstantInt::get(Builder.getInt32Ty(), 0)));
-  }
-
-  int NumVars = isl_space_dim(Kernel->space, isl_dim_param);
-
-  for (long i = 0; i < NumVars; i++) {
-    isl_id *Id = isl_space_get_dim_id(Kernel->space, isl_dim_param, i);
-    Value *Val = IDToValue[Id];
-    isl_id_free(Id);
-    Args.push_back(Val->getType());
-    MemoryType.push_back(
-        ConstantAsMetadata::get(ConstantInt::get(Builder.getInt32Ty(), 0)));
-  }
-
-  for (auto *V : SubtreeValues) {
-    Args.push_back(V->getType());
-    MemoryType.push_back(
-        ConstantAsMetadata::get(ConstantInt::get(Builder.getInt32Ty(), 0)));
-  }
-
-  auto *FT = FunctionType::get(Builder.getVoidTy(), Args, false);
-  auto *FN = Function::Create(FT, Function::ExternalLinkage, Identifier,
-                              GPUModule.get());
-
-  std::vector<Metadata *> EmptyStrings;
-
-  for (unsigned int i = 0; i < MemoryType.size(); i++) {
-    EmptyStrings.push_back(MDString::get(FN->getContext(), ""));
-  }
-
-  if (Arch == GPUArch::SPIR32 || Arch == GPUArch::SPIR64) {
-    FN->setMetadata("kernel_arg_addr_space",
-                    MDNode::get(FN->getContext(), MemoryType));
-    FN->setMetadata("kernel_arg_name",
-                    MDNode::get(FN->getContext(), EmptyStrings));
-    FN->setMetadata("kernel_arg_access_qual",
-                    MDNode::get(FN->getContext(), EmptyStrings));
-    FN->setMetadata("kernel_arg_type",
-                    MDNode::get(FN->getContext(), EmptyStrings));
-    FN->setMetadata("kernel_arg_type_qual",
-                    MDNode::get(FN->getContext(), EmptyStrings));
-    FN->setMetadata("kernel_arg_base_type",
-                    MDNode::get(FN->getContext(), EmptyStrings));
-  }
-
-  switch (Arch) {
-  case GPUArch::NVPTX64:
-    FN->setCallingConv(CallingConv::PTX_Kernel);
-    break;
-  case GPUArch::SPIR32:
-  case GPUArch::SPIR64:
-    FN->setCallingConv(CallingConv::SPIR_KERNEL);
-    break;
-  }
-
-  auto Arg = FN->arg_begin();
-  for (long i = 0; i < Kernel->n_array; i++) {
-    if (!ppcg_kernel_requires_array_argument(Kernel, i))
-      continue;
-
-    Arg->setName(Kernel->array[i].array->name);
-
-    isl_id *Id = isl_space_get_tuple_id(Prog->array[i].space, isl_dim_set);
-    const ScopArrayInfo *SAI = ScopArrayInfo::getFromId(isl::manage_copy(Id));
-    Type *EleTy = SAI->getElementType();
-    Value *Val = &*Arg;
-    SmallVector<const SCEV *, 4> Sizes;
-    isl_ast_build *Build =
-        isl_ast_build_from_context(isl_set_copy(Prog->context));
-    Sizes.push_back(nullptr);
-    for (long j = 1, n = Kernel->array[i].array->n_index; j < n; j++) {
-      isl_ast_expr *DimSize = isl_ast_build_expr_from_pw_aff(
-          Build, isl_multi_pw_aff_get_pw_aff(Kernel->array[i].array->bound, j));
-      auto V = ExprBuilder.create(DimSize);
-      Sizes.push_back(SE.getSCEV(V));
-    }
-    const ScopArrayInfo *SAIRep =
-        S.getOrCreateScopArrayInfo(Val, EleTy, Sizes, MemoryKind::Array);
-    LocalArrays.push_back(Val);
-
-    isl_ast_build_free(Build);
-    KernelIds.push_back(Id);
-    IDToSAI[Id] = SAIRep;
-    Arg++;
-  }
-
-  for (long i = 0; i < NumHostIters; i++) {
-    isl_id *Id = isl_space_get_dim_id(Kernel->space, isl_dim_set, i);
-    Arg->setName(isl_id_get_name(Id));
-    IDToValue[Id] = &*Arg;
-    KernelIDs.insert(std::unique_ptr<isl_id, IslIdDeleter>(Id));
-    Arg++;
-  }
-
-  for (long i = 0; i < NumVars; i++) {
-    isl_id *Id = isl_space_get_dim_id(Kernel->space, isl_dim_param, i);
-    Arg->setName(isl_id_get_name(Id));
-    Value *Val = IDToValue[Id];
-    ValueMap[Val] = &*Arg;
-    IDToValue[Id] = &*Arg;
-    KernelIDs.insert(std::unique_ptr<isl_id, IslIdDeleter>(Id));
-    Arg++;
-  }
-
-  for (auto *V : SubtreeValues) {
-    Arg->setName(V->getName());
-    ValueMap[V] = &*Arg;
-    Arg++;
-  }
-
-  return FN;
-}
-
-void GPUNodeBuilder::insertKernelIntrinsics(ppcg_kernel *Kernel) {
-  Intrinsic::ID IntrinsicsBID[2];
-  Intrinsic::ID IntrinsicsTID[3];
-
-  switch (Arch) {
-  case GPUArch::SPIR64:
-  case GPUArch::SPIR32:
-    llvm_unreachable("Cannot generate NVVM intrinsics for SPIR");
-  case GPUArch::NVPTX64:
-    IntrinsicsBID[0] = Intrinsic::nvvm_read_ptx_sreg_ctaid_x;
-    IntrinsicsBID[1] = Intrinsic::nvvm_read_ptx_sreg_ctaid_y;
-
-    IntrinsicsTID[0] = Intrinsic::nvvm_read_ptx_sreg_tid_x;
-    IntrinsicsTID[1] = Intrinsic::nvvm_read_ptx_sreg_tid_y;
-    IntrinsicsTID[2] = Intrinsic::nvvm_read_ptx_sreg_tid_z;
-    break;
-  }
-
-  auto addId = [this](__isl_take isl_id *Id, Intrinsic::ID Intr) mutable {
-    std::string Name = isl_id_get_name(Id);
-    Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-    Function *IntrinsicFn = Intrinsic::getDeclaration(M, Intr);
-    Value *Val = Builder.CreateCall(IntrinsicFn, {});
-    Val = Builder.CreateIntCast(Val, Builder.getInt64Ty(), false, Name);
-    IDToValue[Id] = Val;
-    KernelIDs.insert(std::unique_ptr<isl_id, IslIdDeleter>(Id));
-  };
-
-  for (int i = 0; i < Kernel->n_grid; ++i) {
-    isl_id *Id = isl_id_list_get_id(Kernel->block_ids, i);
-    addId(Id, IntrinsicsBID[i]);
-  }
-
-  for (int i = 0; i < Kernel->n_block; ++i) {
-    isl_id *Id = isl_id_list_get_id(Kernel->thread_ids, i);
-    addId(Id, IntrinsicsTID[i]);
-  }
-}
-
-void GPUNodeBuilder::insertKernelCallsSPIR(ppcg_kernel *Kernel,
-                                           bool SizeTypeIs64bit) {
-  const char *GroupName[3] = {"__gen_ocl_get_group_id0",
-                              "__gen_ocl_get_group_id1",
-                              "__gen_ocl_get_group_id2"};
-
-  const char *LocalName[3] = {"__gen_ocl_get_local_id0",
-                              "__gen_ocl_get_local_id1",
-                              "__gen_ocl_get_local_id2"};
-  IntegerType *SizeT =
-      SizeTypeIs64bit ? Builder.getInt64Ty() : Builder.getInt32Ty();
-
-  auto createFunc = [this](const char *Name, __isl_take isl_id *Id,
-                           IntegerType *SizeT) mutable {
-    Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-    Function *FN = M->getFunction(Name);
-
-    // If FN is not available, declare it.
-    if (!FN) {
-      GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
-      std::vector<Type *> Args;
-      FunctionType *Ty = FunctionType::get(SizeT, Args, false);
-      FN = Function::Create(Ty, Linkage, Name, M);
-      FN->setCallingConv(CallingConv::SPIR_FUNC);
-    }
-
-    Value *Val = Builder.CreateCall(FN, {});
-    if (SizeT == Builder.getInt32Ty())
-      Val = Builder.CreateIntCast(Val, Builder.getInt64Ty(), false, Name);
-    IDToValue[Id] = Val;
-    KernelIDs.insert(std::unique_ptr<isl_id, IslIdDeleter>(Id));
-  };
-
-  for (int i = 0; i < Kernel->n_grid; ++i)
-    createFunc(GroupName[i], isl_id_list_get_id(Kernel->block_ids, i), SizeT);
-
-  for (int i = 0; i < Kernel->n_block; ++i)
-    createFunc(LocalName[i], isl_id_list_get_id(Kernel->thread_ids, i), SizeT);
-}
-
-void GPUNodeBuilder::prepareKernelArguments(ppcg_kernel *Kernel, Function *FN) {
-  auto Arg = FN->arg_begin();
-  for (long i = 0; i < Kernel->n_array; i++) {
-    if (!ppcg_kernel_requires_array_argument(Kernel, i))
-      continue;
-
-    isl_id *Id = isl_space_get_tuple_id(Prog->array[i].space, isl_dim_set);
-    const ScopArrayInfo *SAI = ScopArrayInfo::getFromId(isl::manage_copy(Id));
-    isl_id_free(Id);
-
-    if (SAI->getNumberOfDimensions() > 0) {
-      Arg++;
-      continue;
-    }
-
-    Value *Val = &*Arg;
-
-    if (!gpu_array_is_read_only_scalar(&Prog->array[i])) {
-      Type *TypePtr = SAI->getElementType()->getPointerTo();
-      Value *TypedArgPtr = Builder.CreatePointerCast(Val, TypePtr);
-      Val = Builder.CreateLoad(SAI->getElementType(), TypedArgPtr);
-    }
-
-    Value *Alloca = BlockGen.getOrCreateAlloca(SAI);
-    Builder.CreateStore(Val, Alloca);
-
-    Arg++;
-  }
-}
-
-void GPUNodeBuilder::finalizeKernelArguments(ppcg_kernel *Kernel) {
-  auto *FN = Builder.GetInsertBlock()->getParent();
-  auto Arg = FN->arg_begin();
-
-  bool StoredScalar = false;
-  for (long i = 0; i < Kernel->n_array; i++) {
-    if (!ppcg_kernel_requires_array_argument(Kernel, i))
-      continue;
-
-    isl_id *Id = isl_space_get_tuple_id(Prog->array[i].space, isl_dim_set);
-    const ScopArrayInfo *SAI = ScopArrayInfo::getFromId(isl::manage_copy(Id));
-    isl_id_free(Id);
-
-    if (SAI->getNumberOfDimensions() > 0) {
-      Arg++;
-      continue;
-    }
-
-    if (gpu_array_is_read_only_scalar(&Prog->array[i])) {
-      Arg++;
-      continue;
-    }
-
-    Value *Alloca = BlockGen.getOrCreateAlloca(SAI);
-    Value *ArgPtr = &*Arg;
-    Type *TypePtr = SAI->getElementType()->getPointerTo();
-    Value *TypedArgPtr = Builder.CreatePointerCast(ArgPtr, TypePtr);
-    Value *Val = Builder.CreateLoad(SAI->getElementType(), Alloca);
-    Builder.CreateStore(Val, TypedArgPtr);
-    StoredScalar = true;
-
-    Arg++;
-  }
-
-  if (StoredScalar) {
-    /// In case more than one thread contains scalar stores, the generated
-    /// code might be incorrect, if we only store at the end of the kernel.
-    /// To support this case we need to store these scalars back at each
-    /// memory store or at least before each kernel barrier.
-    if (Kernel->n_block != 0 || Kernel->n_grid != 0) {
-      BuildSuccessful = 0;
-      LLVM_DEBUG(
-          dbgs() << getUniqueScopName(&S)
-                 << " has a store to a scalar value that"
-                    " would be undefined to run in parallel. Bailing out.\n";);
-    }
-  }
-}
-
-void GPUNodeBuilder::createKernelVariables(ppcg_kernel *Kernel, Function *FN) {
-  Module *M = Builder.GetInsertBlock()->getParent()->getParent();
-
-  for (int i = 0; i < Kernel->n_var; ++i) {
-    struct ppcg_kernel_var &Var = Kernel->var[i];
-    isl_id *Id = isl_space_get_tuple_id(Var.array->space, isl_dim_set);
-    Type *EleTy = ScopArrayInfo::getFromId(isl::manage(Id))->getElementType();
-
-    Type *ArrayTy = EleTy;
-    SmallVector<const SCEV *, 4> Sizes;
-
-    Sizes.push_back(nullptr);
-    for (unsigned int j = 1; j < Var.array->n_index; ++j) {
-      isl_val *Val = isl_vec_get_element_val(Var.size, j);
-      long Bound = isl_val_get_num_si(Val);
-      isl_val_free(Val);
-      Sizes.push_back(S.getSE()->getConstant(Builder.getInt64Ty(), Bound));
-    }
-
-    for (int j = Var.array->n_index - 1; j >= 0; --j) {
-      isl_val *Val = isl_vec_get_element_val(Var.size, j);
-      long Bound = isl_val_get_num_si(Val);
-      isl_val_free(Val);
-      ArrayTy = ArrayType::get(ArrayTy, Bound);
-    }
-
-    const ScopArrayInfo *SAI;
-    Value *Allocation;
-    if (Var.type == ppcg_access_shared) {
-      auto GlobalVar = new GlobalVariable(
-          *M, ArrayTy, false, GlobalValue::InternalLinkage, 0, Var.name,
-          nullptr, GlobalValue::ThreadLocalMode::NotThreadLocal, 3);
-      GlobalVar->setAlignment(llvm::Align(EleTy->getPrimitiveSizeInBits() / 8));
-      GlobalVar->setInitializer(Constant::getNullValue(ArrayTy));
-
-      Allocation = GlobalVar;
-    } else if (Var.type == ppcg_access_private) {
-      Allocation = Builder.CreateAlloca(ArrayTy, 0, "private_array");
-    } else {
-      llvm_unreachable("unknown variable type");
-    }
-    SAI =
-        S.getOrCreateScopArrayInfo(Allocation, EleTy, Sizes, MemoryKind::Array);
-    Id = isl_id_alloc(S.getIslCtx().get(), Var.name, nullptr);
-    IDToValue[Id] = Allocation;
-    LocalArrays.push_back(Allocation);
-    KernelIds.push_back(Id);
-    IDToSAI[Id] = SAI;
-  }
-}
-
-void GPUNodeBuilder::createKernelFunction(
-    ppcg_kernel *Kernel, SetVector<Value *> &SubtreeValues,
-    SetVector<Function *> &SubtreeFunctions) {
-  std::string Identifier = getKernelFuncName(Kernel->id);
-  GPUModule.reset(new Module(Identifier, Builder.getContext()));
-
-  switch (Arch) {
-  case GPUArch::NVPTX64:
-    if (Runtime == GPURuntime::CUDA)
-      GPUModule->setTargetTriple(Triple::normalize("nvptx64-nvidia-cuda"));
-    else if (Runtime == GPURuntime::OpenCL)
-      GPUModule->setTargetTriple(Triple::normalize("nvptx64-nvidia-nvcl"));
-    GPUModule->setDataLayout(computeNVPTXDataLayout(true /* is64Bit */));
-    break;
-  case GPUArch::SPIR32:
-    GPUModule->setTargetTriple(Triple::normalize("spir-unknown-unknown"));
-    GPUModule->setDataLayout(computeSPIRDataLayout(false /* is64Bit */));
-    break;
-  case GPUArch::SPIR64:
-    GPUModule->setTargetTriple(Triple::normalize("spir64-unknown-unknown"));
-    GPUModule->setDataLayout(computeSPIRDataLayout(true /* is64Bit */));
-    break;
-  }
-
-  Function *FN = createKernelFunctionDecl(Kernel, SubtreeValues);
-
-  BasicBlock *PrevBlock = Builder.GetInsertBlock();
-  auto EntryBlock = BasicBlock::Create(Builder.getContext(), "entry", FN);
-
-  DT.addNewBlock(EntryBlock, PrevBlock);
-
-  Builder.SetInsertPoint(EntryBlock);
-  Builder.CreateRetVoid();
-  Builder.SetInsertPoint(EntryBlock, EntryBlock->begin());
-
-  ScopDetection::markFunctionAsInvalid(FN);
-
-  prepareKernelArguments(Kernel, FN);
-  createKernelVariables(Kernel, FN);
-
-  switch (Arch) {
-  case GPUArch::NVPTX64:
-    insertKernelIntrinsics(Kernel);
-    break;
-  case GPUArch::SPIR32:
-    insertKernelCallsSPIR(Kernel, false);
-    break;
-  case GPUArch::SPIR64:
-    insertKernelCallsSPIR(Kernel, true);
-    break;
-  }
-}
-
-std::string GPUNodeBuilder::createKernelASM() {
-  llvm::Triple GPUTriple;
-
-  switch (Arch) {
-  case GPUArch::NVPTX64:
-    switch (Runtime) {
-    case GPURuntime::CUDA:
-      GPUTriple = llvm::Triple(Triple::normalize("nvptx64-nvidia-cuda"));
-      break;
-    case GPURuntime::OpenCL:
-      GPUTriple = llvm::Triple(Triple::normalize("nvptx64-nvidia-nvcl"));
-      break;
-    }
-    break;
-  case GPUArch::SPIR64:
-  case GPUArch::SPIR32:
-    std::string SPIRAssembly;
-    raw_string_ostream IROstream(SPIRAssembly);
-    IROstream << *GPUModule;
-    IROstream.flush();
-    return SPIRAssembly;
-  }
-
-  std::string ErrMsg;
-  auto GPUTarget = TargetRegistry::lookupTarget(GPUTriple.getTriple(), ErrMsg);
-
-  if (!GPUTarget) {
-    errs() << ErrMsg << "\n";
-    return "";
-  }
-
-  TargetOptions Options;
-  Options.UnsafeFPMath = FastMath;
-
-  std::string subtarget;
-
-  switch (Arch) {
-  case GPUArch::NVPTX64:
-    subtarget = CudaVersion;
-    break;
-  case GPUArch::SPIR32:
-  case GPUArch::SPIR64:
-    llvm_unreachable("No subtarget for SPIR architecture");
-  }
-
-  std::unique_ptr<TargetMachine> TargetM(GPUTarget->createTargetMachine(
-      GPUTriple.getTriple(), subtarget, "", Options, std::nullopt));
-
-  SmallString<0> ASMString;
-  raw_svector_ostream ASMStream(ASMString);
-  llvm::legacy::PassManager PM;
-
-  PM.add(createTargetTransformInfoWrapperPass(TargetM->getTargetIRAnalysis()));
-
-  if (TargetM->addPassesToEmitFile(PM, ASMStream, nullptr, CGFT_AssemblyFile,
-                                   true /* verify */)) {
-    errs() << "The target does not support generation of this file type!\n";
-    return "";
-  }
-
-  PM.run(*GPUModule);
-
-  return ASMStream.str().str();
-}
-
-bool GPUNodeBuilder::requiresCUDALibDevice() {
-  bool RequiresLibDevice = false;
-  for (Function &F : GPUModule->functions()) {
-    if (!F.isDeclaration())
-      continue;
-
-    const std::string CUDALibDeviceFunc = getCUDALibDeviceFuntion(F.getName());
-    if (CUDALibDeviceFunc.length() != 0) {
-      // We need to handle the case where a module looks like this:
-      // @expf(..)
-      // @llvm.exp.f64(..)
-      // Both of these functions would be renamed to `__nv_expf`.
-      //
-      // So, we must first check for the existence of the libdevice function.
-      // If this exists, we replace our current function with it.
-      //
-      // If it does not exist, we rename the current function to the
-      // libdevice functiono name.
-      if (Function *Replacement = F.getParent()->getFunction(CUDALibDeviceFunc))
-        F.replaceAllUsesWith(Replacement);
-      else
-        F.setName(CUDALibDeviceFunc);
-      RequiresLibDevice = true;
-    }
-  }
-
-  return RequiresLibDevice;
-}
-
-void GPUNodeBuilder::addCUDALibDevice() {
-  if (Arch != GPUArch::NVPTX64)
-    return;
-
-  if (requiresCUDALibDevice()) {
-    SMDiagnostic Error;
-
-    errs() << CUDALibDevice << "\n";
-    auto LibDeviceModule =
-        parseIRFile(CUDALibDevice, Error, GPUModule->getContext());
-
-    if (!LibDeviceModule) {
-      BuildSuccessful = false;
-      report_fatal_error("Could not find or load libdevice. Skipping GPU "
-                         "kernel generation. Please set -polly-acc-libdevice "
-                         "accordingly.\n");
-      return;
-    }
-
-    Linker L(*GPUModule);
-
-    // Set an nvptx64 target triple to avoid linker warnings. The original
-    // triple of the libdevice files are nvptx-unknown-unknown.
-    LibDeviceModule->setTargetTriple(Triple::normalize("nvptx64-nvidia-cuda"));
-    L.linkInModule(std::move(LibDeviceModule), Linker::LinkOnlyNeeded);
-  }
-}
-
-std::string GPUNodeBuilder::finalizeKernelFunction() {
-
-  if (verifyModule(*GPUModule)) {
-    LLVM_DEBUG(dbgs() << "verifyModule failed on module:\n";
-               GPUModule->print(dbgs(), nullptr); dbgs() << "\n";);
-    LLVM_DEBUG(dbgs() << "verifyModule Error:\n";
-               verifyModule(*GPUModule, &dbgs()););
-
-    if (FailOnVerifyModuleFailure)
-      llvm_unreachable("VerifyModule failed.");
-
-    BuildSuccessful = false;
-    return "";
-  }
-
-  addCUDALibDevice();
-
-  if (DumpKernelIR)
-    outs() << *GPUModule << "\n";
-
-  if (Arch != GPUArch::SPIR32 && Arch != GPUArch::SPIR64) {
-    // Optimize module.
-    llvm::legacy::PassManager OptPasses;
-    PassManagerBuilder PassBuilder;
-    PassBuilder.OptLevel = 3;
-    PassBuilder.SizeLevel = 0;
-    PassBuilder.populateModulePassManager(OptPasses);
-    OptPasses.run(*GPUModule);
-  }
-
-  std::string Assembly = createKernelASM();
-
-  if (DumpKernelASM)
-    outs() << Assembly << "\n";
-
-  GPUModule.release();
-  KernelIDs.clear();
-
-  return Assembly;
-}
-/// Construct an `isl_pw_aff_list` from a vector of `isl_pw_aff`
-/// @param PwAffs The list of piecewise affine functions to create an
-///               `isl_pw_aff_list` from. We expect an rvalue ref because
-///               all the isl_pw_aff are used up by this function.
-///
-/// @returns  The `isl_pw_aff_list`.
-__isl_give isl_pw_aff_list *
-createPwAffList(isl_ctx *Context,
-                const std::vector<__isl_take isl_pw_aff *> &&PwAffs) {
-  isl_pw_aff_list *List = isl_pw_aff_list_alloc(Context, PwAffs.size());
-
-  for (unsigned i = 0; i < PwAffs.size(); i++) {
-    List = isl_pw_aff_list_insert(List, i, PwAffs[i]);
-  }
-  return List;
-}
-
-/// Align all the `PwAffs` such that they have the same parameter dimensions.
-///
-/// We loop over all `pw_aff` and align all of their spaces together to
-/// create a common space for all the `pw_aff`. This common space is the
-/// `AlignSpace`. We then align all the `pw_aff` to this space. We start
-/// with the given `SeedSpace`.
-/// @param PwAffs    The list of piecewise affine functions we want to align.
-///                  This is an rvalue reference because the entire vector is
-///                  used up by the end of the operation.
-/// @param SeedSpace The space to start the alignment process with.
-/// @returns         A std::pair, whose first element is the aligned space,
-///                  whose second element is the vector of aligned piecewise
-///                  affines.
-static std::pair<__isl_give isl_space *, std::vector<__isl_give isl_pw_aff *>>
-alignPwAffs(const std::vector<__isl_take isl_pw_aff *> &&PwAffs,
-            __isl_take isl_space *SeedSpace) {
-  assert(SeedSpace && "Invalid seed space given.");
-
-  isl_space *AlignSpace = SeedSpace;
-  for (isl_pw_aff *PwAff : PwAffs) {
-    isl_space *PwAffSpace = isl_pw_aff_get_domain_space(PwAff);
-    AlignSpace = isl_space_align_params(AlignSpace, PwAffSpace);
-  }
-  std::vector<isl_pw_aff *> AdjustedPwAffs;
-
-  for (unsigned i = 0; i < PwAffs.size(); i++) {
-    isl_pw_aff *Adjusted = PwAffs[i];
-    assert(Adjusted && "Invalid pw_aff given.");
-    Adjusted = isl_pw_aff_align_params(Adjusted, isl_space_copy(AlignSpace));
-    AdjustedPwAffs.push_back(Adjusted);
-  }
-  return std::make_pair(AlignSpace, AdjustedPwAffs);
-}
-
-namespace {
-class PPCGCodeGeneration final : public ScopPass {
-public:
-  static char ID;
-
-  GPURuntime Runtime = GPURuntime::CUDA;
-
-  GPUArch Architecture = GPUArch::NVPTX64;
-
-  /// The scop that is currently processed.
-  Scop *S;
-
-  LoopInfo *LI;
-  DominatorTree *DT;
-  ScalarEvolution *SE;
-  const DataLayout *DL;
-  RegionInfo *RI;
-
-  PPCGCodeGeneration() : ScopPass(ID) {
-    // Apply defaults.
-    Runtime = GPURuntimeChoice;
-    Architecture = GPUArchChoice;
-  }
-
-  /// Construct compilation options for PPCG.
-  ///
-  /// @returns The compilation options.
-  ppcg_options *createPPCGOptions() {
-    auto DebugOptions =
-        (ppcg_debug_options *)malloc(sizeof(ppcg_debug_options));
-    auto Options = (ppcg_options *)malloc(sizeof(ppcg_options));
-
-    DebugOptions->dump_schedule_constraints = false;
-    DebugOptions->dump_schedule = false;
-    DebugOptions->dump_final_schedule = false;
-    DebugOptions->dump_sizes = false;
-    DebugOptions->verbose = false;
-
-    Options->debug = DebugOptions;
-
-    Options->group_chains = false;
-    Options->reschedule = true;
-    Options->scale_tile_loops = false;
-    Options->wrap = false;
-
-    Options->non_negative_parameters = false;
-    Options->ctx = nullptr;
-    Options->sizes = nullptr;
-
-    Options->tile = true;
-    Options->tile_size = 32;
-
-    Options->isolate_full_tiles = false;
-
-    Options->use_private_memory = PrivateMemory;
-    Options->use_shared_memory = SharedMemory;
-    Options->max_shared_memory = 48 * 1024;
-
-    Options->target = PPCG_TARGET_CUDA;
-    Options->openmp = false;
-    Options->linearize_device_arrays = true;
-    Options->allow_gnu_extensions = false;
-
-    Options->unroll_copy_shared = false;
-    Options->unroll_gpu_tile = false;
-    Options->live_range_reordering = true;
-
-    Options->live_range_reordering = true;
-    Options->hybrid = false;
-    Options->opencl_compiler_options = nullptr;
-    Options->opencl_use_gpu = false;
-    Options->opencl_n_include_file = 0;
-    Options->opencl_include_files = nullptr;
-    Options->opencl_print_kernel_types = false;
-    Options->opencl_embed_kernel_code = false;
-
-    Options->save_schedule_file = nullptr;
-    Options->load_schedule_file = nullptr;
-
-    return Options;
-  }
-
-  /// Get a tagged access relation containing all accesses of type @p AccessTy.
-  ///
-  /// Instead of a normal access of the form:
-  ///
-  ///   Stmt[i,j,k] -> Array[f_0(i,j,k), f_1(i,j,k)]
-  ///
-  /// a tagged access has the form
-  ///
-  ///   [Stmt[i,j,k] -> id[]] -> Array[f_0(i,j,k), f_1(i,j,k)]
-  ///
-  /// where 'id' is an additional space that references the memory access that
-  /// triggered the access.
-  ///
-  /// @param AccessTy The type of the memory accesses to collect.
-  ///
-  /// @return The relation describing all tagged memory accesses.
-  isl_union_map *getTaggedAccesses(enum MemoryAccess::AccessType AccessTy) {
-    isl_union_map *Accesses = isl_union_map_empty(S->getParamSpace().release());
-
-    for (auto &Stmt : *S)
-      for (auto &Acc : Stmt)
-        if (Acc->getType() == AccessTy) {
-          isl_map *Relation = Acc->getAccessRelation().release();
-          Relation =
-              isl_map_intersect_domain(Relation, Stmt.getDomain().release());
-
-          isl_space *Space = isl_map_get_space(Relation);
-          Space = isl_space_range(Space);
-          Space = isl_space_from_range(Space);
-          Space =
-              isl_space_set_tuple_id(Space, isl_dim_in, Acc->getId().release());
-          isl_map *Universe = isl_map_universe(Space);
-          Relation = isl_map_domain_product(Relation, Universe);
-          Accesses = isl_union_map_add_map(Accesses, Relation);
-        }
-
-    return Accesses;
-  }
-
-  /// Get the set of all read accesses, tagged with the access id.
-  ///
-  /// @see getTaggedAccesses
-  isl_union_map *getTaggedReads() {
-    return getTaggedAccesses(MemoryAccess::READ);
-  }
-
-  /// Get the set of all may (and must) accesses, tagged with the access id.
-  ///
-  /// @see getTaggedAccesses
-  isl_union_map *getTaggedMayWrites() {
-    return isl_union_map_union(getTaggedAccesses(MemoryAccess::MAY_WRITE),
-                               getTaggedAccesses(MemoryAccess::MUST_WRITE));
-  }
-
-  /// Get the set of all must accesses, tagged with the access id.
-  ///
-  /// @see getTaggedAccesses
-  isl_union_map *getTaggedMustWrites() {
-    return getTaggedAccesses(MemoryAccess::MUST_WRITE);
-  }
-
-  /// Collect parameter and array names as isl_ids.
-  ///
-  /// To reason about the different parameters and arrays used, ppcg requires
-  /// a list of all isl_ids in use. As PPCG traditionally performs
-  /// source-to-source compilation each of these isl_ids is mapped to the
-  /// expression that represents it. As we do not have a corresponding
-  /// expression in Polly, we just map each id to a 'zero' expression to match
-  /// the data format that ppcg expects.
-  ///
-  /// @returns Retun a map from collected ids to 'zero' ast expressions.
-  __isl_give isl_id_to_ast_expr *getNames() {
-    auto *Names = isl_id_to_ast_expr_alloc(
-        S->getIslCtx().get(),
-        S->getNumParams() + std::distance(S->array_begin(), S->array_end()));
-    auto *Zero = isl_ast_expr_from_val(isl_val_zero(S->getIslCtx().get()));
-
-    for (const SCEV *P : S->parameters()) {
-      isl_id *Id = S->getIdForParam(P).release();
-      Names = isl_id_to_ast_expr_set(Names, Id, isl_ast_expr_copy(Zero));
-    }
-
-    for (auto &Array : S->arrays()) {
-      auto Id = Array->getBasePtrId().release();
-      Names = isl_id_to_ast_expr_set(Names, Id, isl_ast_expr_copy(Zero));
-    }
-
-    isl_ast_expr_free(Zero);
-
-    return Names;
-  }
-
-  /// Create a new PPCG scop from the current scop.
-  ///
-  /// The PPCG scop is initialized with data from the current polly::Scop. From
-  /// this initial data, the data-dependences in the PPCG scop are initialized.
-  /// We do not use Polly's dependence analysis for now, to ensure we match
-  /// the PPCG default behaviour more closely.
-  ///
-  /// @returns A new ppcg scop.
-  ppcg_scop *createPPCGScop() {
-    MustKillsInfo KillsInfo = computeMustKillsInfo(*S);
-
-    auto PPCGScop = (ppcg_scop *)malloc(sizeof(ppcg_scop));
-
-    PPCGScop->options = createPPCGOptions();
-    // enable live range reordering
-    PPCGScop->options->live_range_reordering = 1;
-
-    PPCGScop->start = 0;
-    PPCGScop->end = 0;
-
-    PPCGScop->context = S->getContext().release();
-    PPCGScop->domain = S->getDomains().release();
-    // TODO: investigate this further. PPCG calls collect_call_domains.
-    PPCGScop->call = isl_union_set_from_set(S->getContext().release());
-    PPCGScop->tagged_reads = getTaggedReads();
-    PPCGScop->reads = S->getReads().release();
-    PPCGScop->live_in = nullptr;
-    PPCGScop->tagged_may_writes = getTaggedMayWrites();
-    PPCGScop->may_writes = S->getWrites().release();
-    PPCGScop->tagged_must_writes = getTaggedMustWrites();
-    PPCGScop->must_writes = S->getMustWrites().release();
-    PPCGScop->live_out = nullptr;
-    PPCGScop->tagged_must_kills = KillsInfo.TaggedMustKills.release();
-    PPCGScop->must_kills = KillsInfo.MustKills.release();
-
-    PPCGScop->tagger = nullptr;
-    PPCGScop->independence =
-        isl_union_map_empty(isl_set_get_space(PPCGScop->context));
-    PPCGScop->dep_flow = nullptr;
-    PPCGScop->tagged_dep_flow = nullptr;
-    PPCGScop->dep_false = nullptr;
-    PPCGScop->dep_forced = nullptr;
-    PPCGScop->dep_order = nullptr;
-    PPCGScop->tagged_dep_order = nullptr;
-
-    PPCGScop->schedule = S->getScheduleTree().release();
-    // If we have something non-trivial to kill, add it to the schedule
-    if (KillsInfo.KillsSchedule.get())
-      PPCGScop->schedule = isl_schedule_sequence(
-          PPCGScop->schedule, KillsInfo.KillsSchedule.release());
-
-    PPCGScop->names = getNames();
-    PPCGScop->pet = nullptr;
-
-    compute_tagger(PPCGScop);
-    compute_dependences(PPCGScop);
-    eliminate_dead_code(PPCGScop);
-
-    return PPCGScop;
-  }
-
-  /// Collect the array accesses in a statement.
-  ///
-  /// @param Stmt The statement for which to collect the accesses.
-  ///
-  /// @returns A list of array accesses.
-  gpu_stmt_access *getStmtAccesses(ScopStmt &Stmt) {
-    gpu_stmt_access *Accesses = nullptr;
-
-    for (MemoryAccess *Acc : Stmt) {
-      auto Access =
-          isl_alloc_type(S->getIslCtx().get(), struct gpu_stmt_access);
-      Access->read = Acc->isRead();
-      Access->write = Acc->isWrite();
-      Access->access = Acc->getAccessRelation().release();
-      isl_space *Space = isl_map_get_space(Access->access);
-      Space = isl_space_range(Space);
-      Space = isl_space_from_range(Space);
-      Space = isl_space_set_tuple_id(Space, isl_dim_in, Acc->getId().release());
-      isl_map *Universe = isl_map_universe(Space);
-      Access->tagged_access =
-          isl_map_domain_product(Acc->getAccessRelation().release(), Universe);
-      Access->exact_write = !Acc->isMayWrite();
-      Access->ref_id = Acc->getId().release();
-      Access->next = Accesses;
-      Access->n_index = Acc->getScopArrayInfo()->getNumberOfDimensions();
-      // TODO: Also mark one-element accesses to arrays as fixed-element.
-      Access->fixed_element =
-          Acc->isLatestScalarKind() ? isl_bool_true : isl_bool_false;
-      Accesses = Access;
-    }
-
-    return Accesses;
-  }
-
-  /// Collect the list of GPU statements.
-  ///
-  /// Each statement has an id, a pointer to the underlying data structure,
-  /// as well as a list with all memory accesses.
-  ///
-  /// TODO: Initialize the list of memory accesses.
-  ///
-  /// @returns A linked-list of statements.
-  gpu_stmt *getStatements() {
-    gpu_stmt *Stmts = isl_calloc_array(S->getIslCtx().get(), struct gpu_stmt,
-                                       std::distance(S->begin(), S->end()));
-
-    int i = 0;
-    for (auto &Stmt : *S) {
-      gpu_stmt *GPUStmt = &Stmts[i];
-
-      GPUStmt->id = Stmt.getDomainId().release();
-
-      // We use the pet stmt pointer to keep track of the Polly statements.
-      GPUStmt->stmt = (pet_stmt *)&Stmt;
-      GPUStmt->accesses = getStmtAccesses(Stmt);
-      i++;
-    }
-
-    return Stmts;
-  }
-
-  /// Derive the extent of an array.
-  ///
-  /// The extent of an array is the set of elements that are within the
-  /// accessed array. For the inner dimensions, the extent constraints are
-  /// 0 and the size of the corresponding array dimension. For the first
-  /// (outermost) dimension, the extent constraints are the minimal and maximal
-  /// subscript value for the first dimension.
-  ///
-  /// @param Array The array to derive the extent for.
-  ///
-  /// @returns An isl_set describing the extent of the array.
-  isl::set getExtent(ScopArrayInfo *Array) {
-    unsigned NumDims = Array->getNumberOfDimensions();
-
-    if (Array->getNumberOfDimensions() == 0)
-      return isl::set::universe(Array->getSpace());
-
-    isl::union_map Accesses = S->getAccesses(Array);
-    isl::union_set AccessUSet = Accesses.range();
-    AccessUSet = AccessUSet.coalesce();
-    AccessUSet = AccessUSet.detect_equalities();
-    AccessUSet = AccessUSet.coalesce();
-
-    if (AccessUSet.is_empty())
-      return isl::set::empty(Array->getSpace());
-
-    isl::set AccessSet = AccessUSet.extract_set(Array->getSpace());
-
-    isl::local_space LS = isl::local_space(Array->getSpace());
-
-    isl::pw_aff Val = isl::aff::var_on_domain(LS, isl::dim::set, 0);
-    isl::pw_aff OuterMin = AccessSet.dim_min(0);
-    isl::pw_aff OuterMax = AccessSet.dim_max(0);
-    OuterMin = OuterMin.add_dims(isl::dim::in,
-                                 unsignedFromIslSize(Val.dim(isl::dim::in)));
-    OuterMax = OuterMax.add_dims(isl::dim::in,
-                                 unsignedFromIslSize(Val.dim(isl::dim::in)));
-    OuterMin = OuterMin.set_tuple_id(isl::dim::in, Array->getBasePtrId());
-    OuterMax = OuterMax.set_tuple_id(isl::dim::in, Array->getBasePtrId());
-
-    isl::set Extent = isl::set::universe(Array->getSpace());
-
-    Extent = Extent.intersect(OuterMin.le_set(Val));
-    Extent = Extent.intersect(OuterMax.ge_set(Val));
-
-    for (unsigned i = 1; i < NumDims; ++i)
-      Extent = Extent.lower_bound_si(isl::dim::set, i, 0);
-
-    for (unsigned i = 0; i < NumDims; ++i) {
-      isl::pw_aff PwAff = Array->getDimensionSizePw(i);
-
-      // isl_pw_aff can be NULL for zero dimension. Only in the case of a
-      // Fortran array will we have a legitimate dimension.
-      if (PwAff.is_null()) {
-        assert(i == 0 && "invalid dimension isl_pw_aff for nonzero dimension");
-        continue;
-      }
-
-      isl::pw_aff Val = isl::aff::var_on_domain(
-          isl::local_space(Array->getSpace()), isl::dim::set, i);
-      PwAff = PwAff.add_dims(isl::dim::in,
-                             unsignedFromIslSize(Val.dim(isl::dim::in)));
-      PwAff = PwAff.set_tuple_id(isl::dim::in, Val.get_tuple_id(isl::dim::in));
-      isl::set Set = PwAff.gt_set(Val);
-      Extent = Set.intersect(Extent);
-    }
-
-    return Extent;
-  }
-
-  /// Derive the bounds of an array.
-  ///
-  /// For the first dimension we derive the bound of the array from the extent
-  /// of this dimension. For inner dimensions we obtain their size directly from
-  /// ScopArrayInfo.
-  ///
-  /// @param PPCGArray The array to compute bounds for.
-  /// @param Array The polly array from which to take the information.
-  void setArrayBounds(gpu_array_info &PPCGArray, ScopArrayInfo *Array) {
-    std::vector<isl_pw_aff *> Bounds;
-
-    if (PPCGArray.n_index > 0) {
-      if (isl_set_is_empty(PPCGArray.extent)) {
-        isl_set *Dom = isl_set_copy(PPCGArray.extent);
-        isl_local_space *LS = isl_local_space_from_space(
-            isl_space_params(isl_set_get_space(Dom)));
-        isl_set_free(Dom);
-        isl_pw_aff *Zero = isl_pw_aff_from_aff(isl_aff_zero_on_domain(LS));
-        Bounds.push_back(Zero);
-      } else {
-        isl_set *Dom = isl_set_copy(PPCGArray.extent);
-        Dom = isl_set_project_out(Dom, isl_dim_set, 1, PPCGArray.n_index - 1);
-        isl_pw_aff *Bound = isl_set_dim_max(isl_set_copy(Dom), 0);
-        isl_set_free(Dom);
-        Dom = isl_pw_aff_domain(isl_pw_aff_copy(Bound));
-        isl_local_space *LS =
-            isl_local_space_from_space(isl_set_get_space(Dom));
-        isl_aff *One = isl_aff_zero_on_domain(LS);
-        One = isl_aff_add_constant_si(One, 1);
-        Bound = isl_pw_aff_add(Bound, isl_pw_aff_alloc(Dom, One));
-        Bound = isl_pw_aff_gist(Bound, S->getContext().release());
-        Bounds.push_back(Bound);
-      }
-    }
-
-    for (unsigned i = 1; i < PPCGArray.n_index; ++i) {
-      isl_pw_aff *Bound = Array->getDimensionSizePw(i).release();
-      auto LS = isl_pw_aff_get_domain_space(Bound);
-      auto Aff = isl_multi_aff_zero(LS);
-
-      // We need types to work out, which is why we perform this weird dance
-      // with `Aff` and `Bound`. Consider this example:
-
-      // LS: [p] -> { [] }
-      // Zero: [p] -> { [] } | Implicitly, is [p] -> { ~ -> [] }.
-      // This `~` is used to denote a "null space" (which is different from
-      // a *zero dimensional* space), which is something that ISL does not
-      // show you when pretty printing.
-
-      // Bound: [p] -> { [] -> [(10p)] } | Here, the [] is a *zero dimensional*
-      // space, not a "null space" which does not exist at all.
-
-      // When we pullback (precompose) `Bound` with `Zero`, we get:
-      // Bound . Zero =
-      //     ([p] -> { [] -> [(10p)] }) . ([p] -> {~ -> [] }) =
-      //     [p] -> { ~ -> [(10p)] } =
-      //     [p] -> [(10p)] (as ISL pretty prints it)
-      // Bound Pullback: [p] -> { [(10p)] }
-
-      // We want this kind of an expression for Bound, without a
-      // zero dimensional input, but with a "null space" input for the types
-      // to work out later on, as far as I (Siddharth Bhat) understand.
-      // I was unable to find a reference to this in the ISL manual.
-      // References: Tobias Grosser.
-
-      Bound = isl_pw_aff_pullback_multi_aff(Bound, Aff);
-      Bounds.push_back(Bound);
-    }
-
-    /// To construct a `isl_multi_pw_aff`, we need all the indivisual `pw_aff`
-    /// to have the same parameter dimensions. So, we need to align them to an
-    /// appropriate space.
-    /// Scop::Context is _not_ an appropriate space, because when we have
-    /// `-polly-ignore-parameter-bounds` enabled, the Scop::Context does not
-    /// contain all parameter dimensions.
-    /// So, use the helper `alignPwAffs` to align all the `isl_pw_aff` together.
-    isl_space *SeedAlignSpace = S->getParamSpace().release();
-    SeedAlignSpace = isl_space_add_dims(SeedAlignSpace, isl_dim_set, 1);
-
-    isl_space *AlignSpace = nullptr;
-    std::vector<isl_pw_aff *> AlignedBounds;
-    std::tie(AlignSpace, AlignedBounds) =
-        alignPwAffs(std::move(Bounds), SeedAlignSpace);
-
-    assert(AlignSpace && "alignPwAffs did not initialise AlignSpace");
-
-    isl_pw_aff_list *BoundsList =
-        createPwAffList(S->getIslCtx().get(), std::move(AlignedBounds));
-
-    isl_space *BoundsSpace = isl_set_get_space(PPCGArray.extent);
-    BoundsSpace = isl_space_align_params(BoundsSpace, AlignSpace);
-
-    assert(BoundsSpace && "Unable to access space of array.");
-    assert(BoundsList && "Unable to access list of bounds.");
-
-    PPCGArray.bound =
-        isl_multi_pw_aff_from_pw_aff_list(BoundsSpace, BoundsList);
-    assert(PPCGArray.bound && "PPCGArray.bound was not constructed correctly.");
-  }
-
-  /// Create the arrays for @p PPCGProg.
-  ///
-  /// @param PPCGProg The program to compute the arrays for.
-  void createArrays(gpu_prog *PPCGProg,
-                    const SmallVector<ScopArrayInfo *, 4> &ValidSAIs) {
-    int i = 0;
-    for (auto &Array : ValidSAIs) {
-      std::string TypeName;
-      raw_string_ostream OS(TypeName);
-
-      OS << *Array->getElementType();
-      TypeName = OS.str();
-
-      gpu_array_info &PPCGArray = PPCGProg->array[i];
-
-      PPCGArray.space = Array->getSpace().release();
-      PPCGArray.type = strdup(TypeName.c_str());
-      PPCGArray.size = DL->getTypeAllocSize(Array->getElementType());
-      PPCGArray.name = strdup(Array->getName().c_str());
-      PPCGArray.extent = nullptr;
-      PPCGArray.n_index = Array->getNumberOfDimensions();
-      PPCGArray.extent = getExtent(Array).release();
-      PPCGArray.n_ref = 0;
-      PPCGArray.refs = nullptr;
-      PPCGArray.accessed = true;
-      PPCGArray.read_only_scalar =
-          Array->isReadOnly() && Array->getNumberOfDimensions() == 0;
-      PPCGArray.has_compound_element = false;
-      PPCGArray.local = false;
-      PPCGArray.declare_local = false;
-      PPCGArray.global = false;
-      PPCGArray.linearize = false;
-      PPCGArray.dep_order = nullptr;
-      PPCGArray.user = Array;
-
-      PPCGArray.bound = nullptr;
-      setArrayBounds(PPCGArray, Array);
-      i++;
-
-      collect_references(PPCGProg, &PPCGArray);
-      PPCGArray.only_fixed_element = only_fixed_element_accessed(&PPCGArray);
-    }
-  }
-
-  /// Create an identity map between the arrays in the scop.
-  ///
-  /// @returns An identity map between the arrays in the scop.
-  isl_union_map *getArrayIdentity() {
-    isl_union_map *Maps = isl_union_map_empty(S->getParamSpace().release());
-
-    for (auto &Array : S->arrays()) {
-      isl_space *Space = Array->getSpace().release();
-      Space = isl_space_map_from_set(Space);
-      isl_map *Identity = isl_map_identity(Space);
-      Maps = isl_union_map_add_map(Maps, Identity);
-    }
-
-    return Maps;
-  }
-
-  /// Create a default-initialized PPCG GPU program.
-  ///
-  /// @returns A new gpu program description.
-  gpu_prog *createPPCGProg(ppcg_scop *PPCGScop) {
-
-    if (!PPCGScop)
-      return nullptr;
-
-    auto PPCGProg = isl_calloc_type(S->getIslCtx().get(), struct gpu_prog);
-
-    PPCGProg->ctx = S->getIslCtx().get();
-    PPCGProg->scop = PPCGScop;
-    PPCGProg->context = isl_set_copy(PPCGScop->context);
-    PPCGProg->read = isl_union_map_copy(PPCGScop->reads);
-    PPCGProg->may_write = isl_union_map_copy(PPCGScop->may_writes);
-    PPCGProg->must_write = isl_union_map_copy(PPCGScop->must_writes);
-    PPCGProg->tagged_must_kill =
-        isl_union_map_copy(PPCGScop->tagged_must_kills);
-    PPCGProg->to_inner = getArrayIdentity();
-    PPCGProg->to_outer = getArrayIdentity();
-    // TODO: verify that this assignment is correct.
-    PPCGProg->any_to_outer = nullptr;
-    PPCGProg->n_stmts = std::distance(S->begin(), S->end());
-    PPCGProg->stmts = getStatements();
-
-    // Only consider arrays that have a non-empty extent.
-    // Otherwise, this will cause us to consider the following kinds of
-    // empty arrays:
-    //     1. Invariant loads that are represented by SAI objects.
-    //     2. Arrays with statically known zero size.
-    auto ValidSAIsRange =
-        make_filter_range(S->arrays(), [this](ScopArrayInfo *SAI) -> bool {
-          return !getExtent(SAI).is_empty();
-        });
-    SmallVector<ScopArrayInfo *, 4> ValidSAIs(ValidSAIsRange.begin(),
-                                              ValidSAIsRange.end());
-
-    PPCGProg->n_array =
-        ValidSAIs.size(); // std::distance(S->array_begin(), S->array_end());
-    PPCGProg->array = isl_calloc_array(
-        S->getIslCtx().get(), struct gpu_array_info, PPCGProg->n_array);
-
-    createArrays(PPCGProg, ValidSAIs);
-
-    PPCGProg->array_order = nullptr;
-    collect_order_dependences(PPCGProg);
-
-    PPCGProg->may_persist = compute_may_persist(PPCGProg);
-    return PPCGProg;
-  }
-
-  struct PrintGPUUserData {
-    struct cuda_info *CudaInfo;
-    struct gpu_prog *PPCGProg;
-    std::vector<ppcg_kernel *> Kernels;
-  };
-
-  /// Print a user statement node in the host code.
-  ///
-  /// We use ppcg's printing facilities to print the actual statement and
-  /// additionally build up a list of all kernels that are encountered in the
-  /// host ast.
-  ///
-  /// @param P The printer to print to
-  /// @param Options The printing options to use
-  /// @param Node The node to print
-  /// @param User A user pointer to carry additional data. This pointer is
-  ///             expected to be of type PrintGPUUserData.
-  ///
-  /// @returns A printer to which the output has been printed.
-  static __isl_give isl_printer *
-  printHostUser(__isl_take isl_printer *P,
-                __isl_take isl_ast_print_options *Options,
-                __isl_take isl_ast_node *Node, void *User) {
-    auto Data = (struct PrintGPUUserData *)User;
-    auto Id = isl_ast_node_get_annotation(Node);
-
-    if (Id) {
-      bool IsUser = !strcmp(isl_id_get_name(Id), "user");
-
-      // If this is a user statement, format it ourselves as ppcg would
-      // otherwise try to call pet functionality that is not available in
-      // Polly.
-      if (IsUser) {
-        P = isl_printer_start_line(P);
-        P = isl_printer_print_ast_node(P, Node);
-        P = isl_printer_end_line(P);
-        isl_id_free(Id);
-        isl_ast_print_options_free(Options);
-        return P;
-      }
-
-      auto Kernel = (struct ppcg_kernel *)isl_id_get_user(Id);
-      isl_id_free(Id);
-      Data->Kernels.push_back(Kernel);
-    }
-
-    return print_host_user(P, Options, Node, User);
-  }
-
-  /// Print C code corresponding to the control flow in @p Kernel.
-  ///
-  /// @param Kernel The kernel to print
-  void printKernel(ppcg_kernel *Kernel) {
-    auto *P = isl_printer_to_str(S->getIslCtx().get());
-    P = isl_printer_set_output_format(P, ISL_FORMAT_C);
-    auto *Options = isl_ast_print_options_alloc(S->getIslCtx().get());
-    P = isl_ast_node_print(Kernel->tree, P, Options);
-    char *String = isl_printer_get_str(P);
-    outs() << String << "\n";
-    free(String);
-    isl_printer_free(P);
-  }
-
-  /// Print C code corresponding to the GPU code described by @p Tree.
-  ///
-  /// @param Tree An AST describing GPU code
-  /// @param PPCGProg The PPCG program from which @Tree has been constructed.
-  void printGPUTree(isl_ast_node *Tree, gpu_prog *PPCGProg) {
-    auto *P = isl_printer_to_str(S->getIslCtx().get());
-    P = isl_printer_set_output_format(P, ISL_FORMAT_C);
-
-    PrintGPUUserData Data;
-    Data.PPCGProg = PPCGProg;
-
-    auto *Options = isl_ast_print_options_alloc(S->getIslCtx().get());
-    Options =
-        isl_ast_print_options_set_print_user(Options, printHostUser, &Data);
-    P = isl_ast_node_print(Tree, P, Options);
-    char *String = isl_printer_get_str(P);
-    outs() << "# host\n";
-    outs() << String << "\n";
-    free(String);
-    isl_printer_free(P);
-
-    for (auto Kernel : Data.Kernels) {
-      outs() << "# kernel" << Kernel->id << "\n";
-      printKernel(Kernel);
-    }
-  }
-
-  // Generate a GPU program using PPCG.
-  //
-  // GPU mapping consists of multiple steps:
-  //
-  //  1) Compute new schedule for the program.
-  //  2) Map schedule to GPU (TODO)
-  //  3) Generate code for new schedule (TODO)
-  //
-  // We do not use here the Polly ScheduleOptimizer, as the schedule optimizer
-  // is mostly CPU specific. Instead, we use PPCG's GPU code generation
-  // strategy directly from this pass.
-  gpu_gen *generateGPU(ppcg_scop *PPCGScop, gpu_prog *PPCGProg) {
-
-    auto PPCGGen = isl_calloc_type(S->getIslCtx().get(), struct gpu_gen);
-
-    PPCGGen->ctx = S->getIslCtx().get();
-    PPCGGen->options = PPCGScop->options;
-    PPCGGen->print = nullptr;
-    PPCGGen->print_user = nullptr;
-    PPCGGen->build_ast_expr = &pollyBuildAstExprForStmt;
-    PPCGGen->prog = PPCGProg;
-    PPCGGen->tree = nullptr;
-    PPCGGen->types.n = 0;
-    PPCGGen->types.name = nullptr;
-    PPCGGen->sizes = nullptr;
-    PPCGGen->used_sizes = nullptr;
-    PPCGGen->kernel_id = 0;
-
-    // Set scheduling strategy to same strategy PPCG is using.
-    isl_options_set_schedule_serialize_sccs(PPCGGen->ctx, false);
-    isl_options_set_schedule_outer_coincidence(PPCGGen->ctx, true);
-    isl_options_set_schedule_maximize_band_depth(PPCGGen->ctx, true);
-    isl_options_set_schedule_whole_component(PPCGGen->ctx, false);
-
-    isl_schedule *Schedule = get_schedule(PPCGGen);
-
-    int has_permutable = has_any_permutable_node(Schedule);
-
-    Schedule =
-        isl_schedule_align_params(Schedule, S->getFullParamSpace().release());
-
-    if (!has_permutable || has_permutable < 0) {
-      Schedule = isl_schedule_free(Schedule);
-      LLVM_DEBUG(dbgs() << getUniqueScopName(S)
-                        << " does not have permutable bands. Bailing out\n";);
-    } else {
-      const bool CreateTransferToFromDevice = !PollyManagedMemory;
-      Schedule = map_to_device(PPCGGen, Schedule, CreateTransferToFromDevice);
-      PPCGGen->tree = generate_code(PPCGGen, isl_schedule_copy(Schedule));
-    }
-
-    if (DumpSchedule) {
-      isl_printer *P = isl_printer_to_str(S->getIslCtx().get());
-      P = isl_printer_set_yaml_style(P, ISL_YAML_STYLE_BLOCK);
-      P = isl_printer_print_str(P, "Schedule\n");
-      P = isl_printer_print_str(P, "========\n");
-      if (Schedule)
-        P = isl_printer_print_schedule(P, Schedule);
-      else
-        P = isl_printer_print_str(P, "No schedule found\n");
-
-      outs() << isl_printer_get_str(P) << "\n";
-      isl_printer_free(P);
-    }
-
-    if (DumpCode) {
-      outs() << "Code\n";
-      outs() << "====\n";
-      if (PPCGGen->tree)
-        printGPUTree(PPCGGen->tree, PPCGProg);
-      else
-        outs() << "No code generated\n";
-    }
-
-    isl_schedule_free(Schedule);
-
-    return PPCGGen;
-  }
-
-  /// Free gpu_gen structure.
-  ///
-  /// @param PPCGGen The ppcg_gen object to free.
-  void freePPCGGen(gpu_gen *PPCGGen) {
-    isl_ast_node_free(PPCGGen->tree);
-    isl_union_map_free(PPCGGen->sizes);
-    isl_union_map_free(PPCGGen->used_sizes);
-    free(PPCGGen);
-  }
-
-  /// Free the options in the ppcg scop structure.
-  ///
-  /// ppcg is not freeing these options for us. To avoid leaks we do this
-  /// ourselves.
-  ///
-  /// @param PPCGScop The scop referencing the options to free.
-  void freeOptions(ppcg_scop *PPCGScop) {
-    free(PPCGScop->options->debug);
-    PPCGScop->options->debug = nullptr;
-    free(PPCGScop->options);
-    PPCGScop->options = nullptr;
-  }
-
-  /// Approximate the number of points in the set.
-  ///
-  /// This function returns an ast expression that overapproximates the number
-  /// of points in an isl set through the rectangular hull surrounding this set.
-  ///
-  /// @param Set   The set to count.
-  /// @param Build The isl ast build object to use for creating the ast
-  ///              expression.
-  ///
-  /// @returns An approximation of the number of points in the set.
-  __isl_give isl_ast_expr *approxPointsInSet(__isl_take isl_set *Set,
-                                             __isl_keep isl_ast_build *Build) {
-
-    isl_val *One = isl_val_int_from_si(isl_set_get_ctx(Set), 1);
-    auto *Expr = isl_ast_expr_from_val(isl_val_copy(One));
-
-    isl_space *Space = isl_set_get_space(Set);
-    Space = isl_space_params(Space);
-    auto *Univ = isl_set_universe(Space);
-    isl_pw_aff *OneAff = isl_pw_aff_val_on_domain(Univ, One);
-
-    for (long i = 0, n = isl_set_dim(Set, isl_dim_set); i < n; i++) {
-      isl_pw_aff *Max = isl_set_dim_max(isl_set_copy(Set), i);
-      isl_pw_aff *Min = isl_set_dim_min(isl_set_copy(Set), i);
-      isl_pw_aff *DimSize = isl_pw_aff_sub(Max, Min);
-      DimSize = isl_pw_aff_add(DimSize, isl_pw_aff_copy(OneAff));
-      auto DimSizeExpr = isl_ast_build_expr_from_pw_aff(Build, DimSize);
-      Expr = isl_ast_expr_mul(Expr, DimSizeExpr);
-    }
-
-    isl_set_free(Set);
-    isl_pw_aff_free(OneAff);
-
-    return Expr;
-  }
-
-  /// Approximate a number of dynamic instructions executed by a given
-  /// statement.
-  ///
-  /// @param Stmt  The statement for which to compute the number of dynamic
-  ///              instructions.
-  /// @param Build The isl ast build object to use for creating the ast
-  ///              expression.
-  /// @returns An approximation of the number of dynamic instructions executed
-  ///          by @p Stmt.
-  __isl_give isl_ast_expr *approxDynamicInst(ScopStmt &Stmt,
-                                             __isl_keep isl_ast_build *Build) {
-    auto Iterations = approxPointsInSet(Stmt.getDomain().release(), Build);
-
-    long InstCount = 0;
-
-    if (Stmt.isBlockStmt()) {
-      auto *BB = Stmt.getBasicBlock();
-      InstCount = std::distance(BB->begin(), BB->end());
-    } else {
-      auto *R = Stmt.getRegion();
-
-      for (auto *BB : R->blocks()) {
-        InstCount += std::distance(BB->begin(), BB->end());
-      }
-    }
-
-    isl_val *InstVal = isl_val_int_from_si(S->getIslCtx().get(), InstCount);
-    auto *InstExpr = isl_ast_expr_from_val(InstVal);
-    return isl_ast_expr_mul(InstExpr, Iterations);
-  }
-
-  /// Approximate dynamic instructions executed in scop.
-  ///
-  /// @param S     The scop for which to approximate dynamic instructions.
-  /// @param Build The isl ast build object to use for creating the ast
-  ///              expression.
-  /// @returns An approximation of the number of dynamic instructions executed
-  ///          in @p S.
-  __isl_give isl_ast_expr *
-  getNumberOfIterations(Scop &S, __isl_keep isl_ast_build *Build) {
-    isl_ast_expr *Instructions;
-
-    isl_val *Zero = isl_val_int_from_si(S.getIslCtx().get(), 0);
-    Instructions = isl_ast_expr_from_val(Zero);
-
-    for (ScopStmt &Stmt : S) {
-      isl_ast_expr *StmtInstructions = approxDynamicInst(Stmt, Build);
-      Instructions = isl_ast_expr_add(Instructions, StmtInstructions);
-    }
-    return Instructions;
-  }
-
-  /// Create a check that ensures sufficient compute in scop.
-  ///
-  /// @param S     The scop for which to ensure sufficient compute.
-  /// @param Build The isl ast build object to use for creating the ast
-  ///              expression.
-  /// @returns An expression that evaluates to TRUE in case of sufficient
-  ///          compute and to FALSE, otherwise.
-  __isl_give isl_ast_expr *
-  createSufficientComputeCheck(Scop &S, __isl_keep isl_ast_build *Build) {
-    auto Iterations = getNumberOfIterations(S, Build);
-    auto *MinComputeVal = isl_val_int_from_si(S.getIslCtx().get(), MinCompute);
-    auto *MinComputeExpr = isl_ast_expr_from_val(MinComputeVal);
-    return isl_ast_expr_ge(Iterations, MinComputeExpr);
-  }
-
-  /// Check if the basic block contains a function we cannot codegen for GPU
-  /// kernels.
-  ///
-  /// If this basic block does something with a `Function` other than calling
-  /// a function that we support in a kernel, return true.
-  bool containsInvalidKernelFunctionInBlock(const BasicBlock *BB,
-                                            bool AllowCUDALibDevice) {
-    for (const Instruction &Inst : *BB) {
-      const CallInst *Call = dyn_cast<CallInst>(&Inst);
-      if (Call && isValidFunctionInKernel(Call->getCalledFunction(),
-                                          AllowCUDALibDevice))
-        continue;
-
-      for (Value *Op : Inst.operands())
-        // Look for functions among operands of Inst.
-        if (isa<Function>(Op->stripPointerCasts())) {
-          LLVM_DEBUG(dbgs()
-                     << Inst << " has illegal use of function in kernel.\n");
-          return true;
-        }
-    }
-    return false;
-  }
-
-  /// Return whether the Scop S uses functions in a way that we do not support.
-  bool containsInvalidKernelFunction(const Scop &S, bool AllowCUDALibDevice) {
-    for (auto &Stmt : S) {
-      if (Stmt.isBlockStmt()) {
-        if (containsInvalidKernelFunctionInBlock(Stmt.getBasicBlock(),
-                                                 AllowCUDALibDevice))
-          return true;
-      } else {
-        assert(Stmt.isRegionStmt() &&
-               "Stmt was neither block nor region statement");
-        for (const BasicBlock *BB : Stmt.getRegion()->blocks())
-          if (containsInvalidKernelFunctionInBlock(BB, AllowCUDALibDevice))
-            return true;
-      }
-    }
-    return false;
-  }
-
-  /// Generate code for a given GPU AST described by @p Root.
-  ///
-  /// @param Root An isl_ast_node pointing to the root of the GPU AST.
-  /// @param Prog The GPU Program to generate code for.
-  void generateCode(__isl_take isl_ast_node *Root, gpu_prog *Prog) {
-    ScopAnnotator Annotator;
-    Annotator.buildAliasScopes(*S);
-
-    Region *R = &S->getRegion();
-
-    simplifyRegion(R, DT, LI, RI);
-
-    BasicBlock *EnteringBB = R->getEnteringBlock();
-
-    PollyIRBuilder Builder(EnteringBB->getContext(), ConstantFolder(),
-                           IRInserter(Annotator));
-    Builder.SetInsertPoint(EnteringBB->getTerminator());
-
-    // Only build the run-time condition and parameters _after_ having
-    // introduced the conditional branch. This is important as the conditional
-    // branch will guard the original scop from new induction variables that
-    // the SCEVExpander may introduce while code generating the parameters and
-    // which may introduce scalar dependences that prevent us from correctly
-    // code generating this scop.
-    BBPair StartExitBlocks;
-    BranchInst *CondBr = nullptr;
-    std::tie(StartExitBlocks, CondBr) =
-        executeScopConditionally(*S, Builder.getTrue(), *DT, *RI, *LI);
-    BasicBlock *StartBlock = std::get<0>(StartExitBlocks);
-
-    assert(CondBr && "CondBr not initialized by executeScopConditionally");
-
-    GPUNodeBuilder NodeBuilder(Builder, Annotator, *DL, *LI, *SE, *DT, *S,
-                               StartBlock, Prog, Runtime, Architecture);
-
-    // TODO: Handle LICM
-    auto SplitBlock = StartBlock->getSinglePredecessor();
-    Builder.SetInsertPoint(SplitBlock->getTerminator());
-
-    isl_ast_build *Build = isl_ast_build_alloc(S->getIslCtx().get());
-    isl::ast_expr Condition =
-        IslAst::buildRunCondition(*S, isl::manage_copy(Build));
-    isl_ast_expr *SufficientCompute = createSufficientComputeCheck(*S, Build);
-    Condition =
-        isl::manage(isl_ast_expr_and(Condition.release(), SufficientCompute));
-    isl_ast_build_free(Build);
-
-    // preload invariant loads. Note: This should happen before the RTC
-    // because the RTC may depend on values that are invariant load hoisted.
-    if (!NodeBuilder.preloadInvariantLoads()) {
-      // Patch the introduced branch condition to ensure that we always execute
-      // the original SCoP.
-      auto *FalseI1 = Builder.getFalse();
-      auto *SplitBBTerm = Builder.GetInsertBlock()->getTerminator();
-      SplitBBTerm->setOperand(0, FalseI1);
-
-      LLVM_DEBUG(dbgs() << "preloading invariant loads failed in function: " +
-                               S->getFunction().getName() +
-                               " | Scop Region: " + S->getNameStr());
-      // adjust the dominator tree accordingly.
-      auto *ExitingBlock = StartBlock->getUniqueSuccessor();
-      assert(ExitingBlock);
-      auto *MergeBlock = ExitingBlock->getUniqueSuccessor();
-      assert(MergeBlock);
-      polly::markBlockUnreachable(*StartBlock, Builder);
-      polly::markBlockUnreachable(*ExitingBlock, Builder);
-      auto *ExitingBB = S->getExitingBlock();
-      assert(ExitingBB);
-
-      DT->changeImmediateDominator(MergeBlock, ExitingBB);
-      DT->eraseNode(ExitingBlock);
-      isl_ast_node_free(Root);
-    } else {
-
-      if (polly::PerfMonitoring) {
-        PerfMonitor P(*S, EnteringBB->getParent()->getParent());
-        P.initialize();
-        P.insertRegionStart(SplitBlock->getTerminator());
-
-        // TODO: actually think if this is the correct exiting block to place
-        // the `end` performance marker. Invariant load hoisting changes
-        // the CFG in a way that I do not precisely understand, so I
-        // (Siddharth<siddu.druid@gmail.com>) should come back to this and
-        // think about which exiting block to use.
-        auto *ExitingBlock = StartBlock->getUniqueSuccessor();
-        assert(ExitingBlock);
-        BasicBlock *MergeBlock = ExitingBlock->getUniqueSuccessor();
-        P.insertRegionEnd(MergeBlock->getTerminator());
-      }
-
-      NodeBuilder.addParameters(S->getContext().release());
-      Value *RTC = NodeBuilder.createRTC(Condition.release());
-      Builder.GetInsertBlock()->getTerminator()->setOperand(0, RTC);
-
-      Builder.SetInsertPoint(&*StartBlock->begin());
-
-      NodeBuilder.create(Root);
-    }
-
-    /// In case a sequential kernel has more surrounding loops as any parallel
-    /// kernel, the SCoP is probably mostly sequential. Hence, there is no
-    /// point in running it on a GPU.
-    if (NodeBuilder.DeepestSequential > NodeBuilder.DeepestParallel)
-      CondBr->setOperand(0, Builder.getFalse());
-
-    if (!NodeBuilder.BuildSuccessful)
-      CondBr->setOperand(0, Builder.getFalse());
-  }
-
-  bool runOnScop(Scop &CurrentScop) override {
-    S = &CurrentScop;
-    LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
-    DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-    SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
-    DL = &S->getRegion().getEntry()->getModule()->getDataLayout();
-    RI = &getAnalysis<RegionInfoPass>().getRegionInfo();
-
-    LLVM_DEBUG(dbgs() << "PPCGCodeGen running on : " << getUniqueScopName(S)
-                      << " | loop depth: " << S->getMaxLoopDepth() << "\n");
-
-    // We currently do not support functions other than intrinsics inside
-    // kernels, as code generation will need to offload function calls to the
-    // kernel. This may lead to a kernel trying to call a function on the host.
-    // This also allows us to prevent codegen from trying to take the
-    // address of an intrinsic function to send to the kernel.
-    if (containsInvalidKernelFunction(CurrentScop,
-                                      Architecture == GPUArch::NVPTX64)) {
-      LLVM_DEBUG(
-          dbgs() << getUniqueScopName(S)
-                 << " contains function which cannot be materialised in a GPU "
-                    "kernel. Bailing out.\n";);
-      return false;
-    }
-
-    auto PPCGScop = createPPCGScop();
-    auto PPCGProg = createPPCGProg(PPCGScop);
-    auto PPCGGen = generateGPU(PPCGScop, PPCGProg);
-
-    if (PPCGGen->tree) {
-      generateCode(isl_ast_node_copy(PPCGGen->tree), PPCGProg);
-      CurrentScop.markAsToBeSkipped();
-    } else {
-      LLVM_DEBUG(dbgs() << getUniqueScopName(S)
-                        << " has empty PPCGGen->tree. Bailing out.\n");
-    }
-
-    freeOptions(PPCGScop);
-    freePPCGGen(PPCGGen);
-    gpu_prog_free(PPCGProg);
-    ppcg_scop_free(PPCGScop);
-
-    return true;
-  }
-
-  void printScop(raw_ostream &, Scop &) const override {}
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    ScopPass::getAnalysisUsage(AU);
-
-    AU.addRequired<DominatorTreeWrapperPass>();
-    AU.addRequired<RegionInfoPass>();
-    AU.addRequired<ScalarEvolutionWrapperPass>();
-    AU.addRequired<ScopDetectionWrapperPass>();
-    AU.addRequired<ScopInfoRegionPass>();
-    AU.addRequired<LoopInfoWrapperPass>();
-
-    // FIXME: We do not yet add regions for the newly generated code to the
-    //        region tree.
-  }
-};
-} // namespace
-
-char PPCGCodeGeneration::ID = 1;
-
-Pass *polly::createPPCGCodeGenerationPass(GPUArch Arch, GPURuntime Runtime) {
-  PPCGCodeGeneration *generator = new PPCGCodeGeneration();
-  generator->Runtime = Runtime;
-  generator->Architecture = Arch;
-  return generator;
-}
-
-INITIALIZE_PASS_BEGIN(PPCGCodeGeneration, "polly-codegen-ppcg",
-                      "Polly - Apply PPCG translation to SCOP", false, false)
-INITIALIZE_PASS_DEPENDENCY(DependenceInfo);
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass);
-INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
-INITIALIZE_PASS_DEPENDENCY(RegionInfoPass);
-INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass);
-INITIALIZE_PASS_DEPENDENCY(ScopDetectionWrapperPass);
-INITIALIZE_PASS_END(PPCGCodeGeneration, "polly-codegen-ppcg",
-                    "Polly - Apply PPCG translation to SCOP", false, false)