OMPIRBuilder.cpp

Go to the documentation of this file.

//===- OpenMPIRBuilder.cpp - Builder for LLVM-IR for OpenMP directives ----===//
//
// 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
//
//===----------------------------------------------------------------------===//
/// \file
///
/// This file implements the OpenMPIRBuilder class, which is used as a
/// convenient way to create LLVM instructions for OpenMP directives.
///
//===----------------------------------------------------------------------===//
 
#include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/CodeMetrics.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/Value.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/CodeExtractor.h"
#include "llvm/Transforms/Utils/LoopPeel.h"
#include "llvm/Transforms/Utils/UnrollLoop.h"
 
#include <cstdint>
#include <optional>
 
#define DEBUG_TYPE "openmp-ir-builder"
 
using namespace llvm;
using namespace omp;
 
static cl::opt<bool>
    OptimisticAttributes("openmp-ir-builder-optimistic-attributes", cl::Hidden,
                         cl::desc("Use optimistic attributes describing "
                                  "'as-if' properties of runtime calls."),
                         cl::init(false));
 
static cl::opt<double> UnrollThresholdFactor(
    "openmp-ir-builder-unroll-threshold-factor", cl::Hidden,
    cl::desc("Factor for the unroll threshold to account for code "
             "simplifications still taking place"),
    cl::init(1.5));
 
#ifndef NDEBUG
/// Return whether IP1 and IP2 are ambiguous, i.e. that inserting instructions
/// at position IP1 may change the meaning of IP2 or vice-versa. This is because
/// an InsertPoint stores the instruction before something is inserted. For
/// instance, if both point to the same instruction, two IRBuilders alternating
/// creating instruction will cause the instructions to be interleaved.
static bool isConflictIP(IRBuilder<>::InsertPoint IP1,
                         IRBuilder<>::InsertPoint IP2) {
  if (!IP1.isSet() || !IP2.isSet())
    return false;
  return IP1.getBlock() == IP2.getBlock() && IP1.getPoint() == IP2.getPoint();
}
 
static bool isValidWorkshareLoopScheduleType(OMPScheduleType SchedType) {
  // Valid ordered/unordered and base algorithm combinations.
  switch (SchedType & ~OMPScheduleType::MonotonicityMask) {
  case OMPScheduleType::UnorderedStaticChunked:
  case OMPScheduleType::UnorderedStatic:
  case OMPScheduleType::UnorderedDynamicChunked:
  case OMPScheduleType::UnorderedGuidedChunked:
  case OMPScheduleType::UnorderedRuntime:
  case OMPScheduleType::UnorderedAuto:
  case OMPScheduleType::UnorderedTrapezoidal:
  case OMPScheduleType::UnorderedGreedy:
  case OMPScheduleType::UnorderedBalanced:
  case OMPScheduleType::UnorderedGuidedIterativeChunked:
  case OMPScheduleType::UnorderedGuidedAnalyticalChunked:
  case OMPScheduleType::UnorderedSteal:
  case OMPScheduleType::UnorderedStaticBalancedChunked:
  case OMPScheduleType::UnorderedGuidedSimd:
  case OMPScheduleType::UnorderedRuntimeSimd:
  case OMPScheduleType::OrderedStaticChunked:
  case OMPScheduleType::OrderedStatic:
  case OMPScheduleType::OrderedDynamicChunked:
  case OMPScheduleType::OrderedGuidedChunked:
  case OMPScheduleType::OrderedRuntime:
  case OMPScheduleType::OrderedAuto:
  case OMPScheduleType::OrderdTrapezoidal:
  case OMPScheduleType::NomergeUnorderedStaticChunked:
  case OMPScheduleType::NomergeUnorderedStatic:
  case OMPScheduleType::NomergeUnorderedDynamicChunked:
  case OMPScheduleType::NomergeUnorderedGuidedChunked:
  case OMPScheduleType::NomergeUnorderedRuntime:
  case OMPScheduleType::NomergeUnorderedAuto:
  case OMPScheduleType::NomergeUnorderedTrapezoidal:
  case OMPScheduleType::NomergeUnorderedGreedy:
  case OMPScheduleType::NomergeUnorderedBalanced:
  case OMPScheduleType::NomergeUnorderedGuidedIterativeChunked:
  case OMPScheduleType::NomergeUnorderedGuidedAnalyticalChunked:
  case OMPScheduleType::NomergeUnorderedSteal:
  case OMPScheduleType::NomergeOrderedStaticChunked:
  case OMPScheduleType::NomergeOrderedStatic:
  case OMPScheduleType::NomergeOrderedDynamicChunked:
  case OMPScheduleType::NomergeOrderedGuidedChunked:
  case OMPScheduleType::NomergeOrderedRuntime:
  case OMPScheduleType::NomergeOrderedAuto:
  case OMPScheduleType::NomergeOrderedTrapezoidal:
    break;
  default:
    return false;
  }
 
  // Must not set both monotonicity modifiers at the same time.
  OMPScheduleType MonotonicityFlags =
      SchedType & OMPScheduleType::MonotonicityMask;
  if (MonotonicityFlags == OMPScheduleType::MonotonicityMask)
    return false;
 
  return true;
}
#endif
 
/// Determine which scheduling algorithm to use, determined from schedule clause
/// arguments.
static OMPScheduleType
getOpenMPBaseScheduleType(llvm::omp::ScheduleKind ClauseKind, bool HasChunks,
                          bool HasSimdModifier) {
  // Currently, the default schedule it static.
  switch (ClauseKind) {
  case OMP_SCHEDULE_Default:
  case OMP_SCHEDULE_Static:
    return HasChunks ? OMPScheduleType::BaseStaticChunked
                     : OMPScheduleType::BaseStatic;
  case OMP_SCHEDULE_Dynamic:
    return OMPScheduleType::BaseDynamicChunked;
  case OMP_SCHEDULE_Guided:
    return HasSimdModifier ? OMPScheduleType::BaseGuidedSimd
                           : OMPScheduleType::BaseGuidedChunked;
  case OMP_SCHEDULE_Auto:
    return llvm::omp::OMPScheduleType::BaseAuto;
  case OMP_SCHEDULE_Runtime:
    return HasSimdModifier ? OMPScheduleType::BaseRuntimeSimd
                           : OMPScheduleType::BaseRuntime;
  }
  llvm_unreachable("unhandled schedule clause argument");
}
 
/// Adds ordering modifier flags to schedule type.
static OMPScheduleType
getOpenMPOrderingScheduleType(OMPScheduleType BaseScheduleType,
                              bool HasOrderedClause) {
  assert((BaseScheduleType & OMPScheduleType::ModifierMask) ==
             OMPScheduleType::None &&
         "Must not have ordering nor monotonicity flags already set");
 
  OMPScheduleType OrderingModifier = HasOrderedClause
                                         ? OMPScheduleType::ModifierOrdered
                                         : OMPScheduleType::ModifierUnordered;
  OMPScheduleType OrderingScheduleType = BaseScheduleType | OrderingModifier;
 
  // Unsupported combinations
  if (OrderingScheduleType ==
      (OMPScheduleType::BaseGuidedSimd | OMPScheduleType::ModifierOrdered))
    return OMPScheduleType::OrderedGuidedChunked;
  else if (OrderingScheduleType == (OMPScheduleType::BaseRuntimeSimd |
                                    OMPScheduleType::ModifierOrdered))
    return OMPScheduleType::OrderedRuntime;
 
  return OrderingScheduleType;
}
 
/// Adds monotonicity modifier flags to schedule type.
static OMPScheduleType
getOpenMPMonotonicityScheduleType(OMPScheduleType ScheduleType,
                                  bool HasSimdModifier, bool HasMonotonic,
                                  bool HasNonmonotonic, bool HasOrderedClause) {
  assert((ScheduleType & OMPScheduleType::MonotonicityMask) ==
             OMPScheduleType::None &&
         "Must not have monotonicity flags already set");
  assert((!HasMonotonic || !HasNonmonotonic) &&
         "Monotonic and Nonmonotonic are contradicting each other");
 
  if (HasMonotonic) {
    return ScheduleType | OMPScheduleType::ModifierMonotonic;
  } else if (HasNonmonotonic) {
    return ScheduleType | OMPScheduleType::ModifierNonmonotonic;
  } else {
    // OpenMP 5.1, 2.11.4 Worksharing-Loop Construct, Description.
    // If the static schedule kind is specified or if the ordered clause is
    // specified, and if the nonmonotonic modifier is not specified, the
    // effect is as if the monotonic modifier is specified. Otherwise, unless
    // the monotonic modifier is specified, the effect is as if the
    // nonmonotonic modifier is specified.
    OMPScheduleType BaseScheduleType =
        ScheduleType & ~OMPScheduleType::ModifierMask;
    if ((BaseScheduleType == OMPScheduleType::BaseStatic) ||
        (BaseScheduleType == OMPScheduleType::BaseStaticChunked) ||
        HasOrderedClause) {
      // The monotonic is used by default in openmp runtime library, so no need
      // to set it.
      return ScheduleType;
    } else {
      return ScheduleType | OMPScheduleType::ModifierNonmonotonic;
    }
  }
}
 
/// Determine the schedule type using schedule and ordering clause arguments.
static OMPScheduleType
computeOpenMPScheduleType(ScheduleKind ClauseKind, bool HasChunks,
                          bool HasSimdModifier, bool HasMonotonicModifier,
                          bool HasNonmonotonicModifier, bool HasOrderedClause) {
  OMPScheduleType BaseSchedule =
      getOpenMPBaseScheduleType(ClauseKind, HasChunks, HasSimdModifier);
  OMPScheduleType OrderedSchedule =
      getOpenMPOrderingScheduleType(BaseSchedule, HasOrderedClause);
  OMPScheduleType Result = getOpenMPMonotonicityScheduleType(
      OrderedSchedule, HasSimdModifier, HasMonotonicModifier,
      HasNonmonotonicModifier, HasOrderedClause);
 
  assert(isValidWorkshareLoopScheduleType(Result));
  return Result;
}
 
/// Make \p Source branch to \p Target.
///
/// Handles two situations:
/// * \p Source already has an unconditional branch.
/// * \p Source is a degenerate block (no terminator because the BB is
///             the current head of the IR construction).
static void redirectTo(BasicBlock *Source, BasicBlock *Target, DebugLoc DL) {
  if (Instruction *Term = Source->getTerminator()) {
    auto *Br = cast<BranchInst>(Term);
    assert(!Br->isConditional() &&
           "BB's terminator must be an unconditional branch (or degenerate)");
    BasicBlock *Succ = Br->getSuccessor(0);
    Succ->removePredecessor(Source, /*KeepOneInputPHIs=*/true);
    Br->setSuccessor(0, Target);
    return;
  }
 
  auto *NewBr = BranchInst::Create(Target, Source);
  NewBr->setDebugLoc(DL);
}
 
void llvm::spliceBB(IRBuilderBase::InsertPoint IP, BasicBlock *New,
                    bool CreateBranch) {
  assert(New->getFirstInsertionPt() == New->begin() &&
         "Target BB must not have PHI nodes");
 
  // Move instructions to new block.
  BasicBlock *Old = IP.getBlock();
  New->splice(New->begin(), Old, IP.getPoint(), Old->end());
 
  if (CreateBranch)
    BranchInst::Create(New, Old);
}
 
void llvm::spliceBB(IRBuilder<> &Builder, BasicBlock *New, bool CreateBranch) {
  DebugLoc DebugLoc = Builder.getCurrentDebugLocation();
  BasicBlock *Old = Builder.GetInsertBlock();
 
  spliceBB(Builder.saveIP(), New, CreateBranch);
  if (CreateBranch)
    Builder.SetInsertPoint(Old->getTerminator());
  else
    Builder.SetInsertPoint(Old);
 
  // SetInsertPoint also updates the Builder's debug location, but we want to
  // keep the one the Builder was configured to use.
  Builder.SetCurrentDebugLocation(DebugLoc);
}
 
BasicBlock *llvm::splitBB(IRBuilderBase::InsertPoint IP, bool CreateBranch,
                          llvm::Twine Name) {
  BasicBlock *Old = IP.getBlock();
  BasicBlock *New = BasicBlock::Create(
      Old->getContext(), Name.isTriviallyEmpty() ? Old->getName() : Name,
      Old->getParent(), Old->getNextNode());
  spliceBB(IP, New, CreateBranch);
  New->replaceSuccessorsPhiUsesWith(Old, New);
  return New;
}
 
BasicBlock *llvm::splitBB(IRBuilderBase &Builder, bool CreateBranch,
                          llvm::Twine Name) {
  DebugLoc DebugLoc = Builder.getCurrentDebugLocation();
  BasicBlock *New = splitBB(Builder.saveIP(), CreateBranch, Name);
  if (CreateBranch)
    Builder.SetInsertPoint(Builder.GetInsertBlock()->getTerminator());
  else
    Builder.SetInsertPoint(Builder.GetInsertBlock());
  // SetInsertPoint also updates the Builder's debug location, but we want to
  // keep the one the Builder was configured to use.
  Builder.SetCurrentDebugLocation(DebugLoc);
  return New;
}
 
BasicBlock *llvm::splitBB(IRBuilder<> &Builder, bool CreateBranch,
                          llvm::Twine Name) {
  DebugLoc DebugLoc = Builder.getCurrentDebugLocation();
  BasicBlock *New = splitBB(Builder.saveIP(), CreateBranch, Name);
  if (CreateBranch)
    Builder.SetInsertPoint(Builder.GetInsertBlock()->getTerminator());
  else
    Builder.SetInsertPoint(Builder.GetInsertBlock());
  // SetInsertPoint also updates the Builder's debug location, but we want to
  // keep the one the Builder was configured to use.
  Builder.SetCurrentDebugLocation(DebugLoc);
  return New;
}
 
BasicBlock *llvm::splitBBWithSuffix(IRBuilderBase &Builder, bool CreateBranch,
                                    llvm::Twine Suffix) {
  BasicBlock *Old = Builder.GetInsertBlock();
  return splitBB(Builder, CreateBranch, Old->getName() + Suffix);
}
 
void OpenMPIRBuilder::addAttributes(omp::RuntimeFunction FnID, Function &Fn) {
  LLVMContext &Ctx = Fn.getContext();
  Triple T(M.getTargetTriple());
 
  // Get the function's current attributes.
  auto Attrs = Fn.getAttributes();
  auto FnAttrs = Attrs.getFnAttrs();
  auto RetAttrs = Attrs.getRetAttrs();
  SmallVector<AttributeSet, 4> ArgAttrs;
  for (size_t ArgNo = 0; ArgNo < Fn.arg_size(); ++ArgNo)
    ArgAttrs.emplace_back(Attrs.getParamAttrs(ArgNo));
 
  // Add AS to FnAS while taking special care with integer extensions.
  auto addAttrSet = [&](AttributeSet &FnAS, const AttributeSet &AS,
                        bool Param = true) -> void {
    bool HasSignExt = AS.hasAttribute(Attribute::SExt);
    bool HasZeroExt = AS.hasAttribute(Attribute::ZExt);
    if (HasSignExt || HasZeroExt) {
      assert(AS.getNumAttributes() == 1 &&
             "Currently not handling extension attr combined with others.");
      if (Param) {
        if (auto AK = TargetLibraryInfo::getExtAttrForI32Param(T, HasSignExt))
          FnAS = FnAS.addAttribute(Ctx, AK);
      } else
        if (auto AK = TargetLibraryInfo::getExtAttrForI32Return(T, HasSignExt))
          FnAS = FnAS.addAttribute(Ctx, AK);
    } else {
      FnAS = FnAS.addAttributes(Ctx, AS);
    }
  };
 
#define OMP_ATTRS_SET(VarName, AttrSet) AttributeSet VarName = AttrSet;
#include "llvm/Frontend/OpenMP/OMPKinds.def"
 
  // Add attributes to the function declaration.
  switch (FnID) {
#define OMP_RTL_ATTRS(Enum, FnAttrSet, RetAttrSet, ArgAttrSets)                \
  case Enum:                                                                   \
    FnAttrs = FnAttrs.addAttributes(Ctx, FnAttrSet);                           \
    addAttrSet(RetAttrs, RetAttrSet, /*Param*/false);                          \
    for (size_t ArgNo = 0; ArgNo < ArgAttrSets.size(); ++ArgNo)                \
      addAttrSet(ArgAttrs[ArgNo], ArgAttrSets[ArgNo]);                         \
    Fn.setAttributes(AttributeList::get(Ctx, FnAttrs, RetAttrs, ArgAttrs));    \
    break;
#include "llvm/Frontend/OpenMP/OMPKinds.def"
  default:
    // Attributes are optional.
    break;
  }
}
 
FunctionCallee
OpenMPIRBuilder::getOrCreateRuntimeFunction(Module &M, RuntimeFunction FnID) {
  FunctionType *FnTy = nullptr;
  Function *Fn = nullptr;
 
  // Try to find the declation in the module first.
  switch (FnID) {
#define OMP_RTL(Enum, Str, IsVarArg, ReturnType, ...)                          \
  case Enum:                                                                   \
    FnTy = FunctionType::get(ReturnType, ArrayRef<Type *>{__VA_ARGS__},        \
                             IsVarArg);                                        \
    Fn = M.getFunction(Str);                                                   \
    break;
#include "llvm/Frontend/OpenMP/OMPKinds.def"
  }
 
  if (!Fn) {
    // Create a new declaration if we need one.
    switch (FnID) {
#define OMP_RTL(Enum, Str, ...)                                                \
  case Enum:                                                                   \
    Fn = Function::Create(FnTy, GlobalValue::ExternalLinkage, Str, M);         \
    break;
#include "llvm/Frontend/OpenMP/OMPKinds.def"
    }
 
    // Add information if the runtime function takes a callback function
    if (FnID == OMPRTL___kmpc_fork_call || FnID == OMPRTL___kmpc_fork_teams) {
      if (!Fn->hasMetadata(LLVMContext::MD_callback)) {
        LLVMContext &Ctx = Fn->getContext();
        MDBuilder MDB(Ctx);
        // Annotate the callback behavior of the runtime function:
        //  - The callback callee is argument number 2 (microtask).
        //  - The first two arguments of the callback callee are unknown (-1).
        //  - All variadic arguments to the runtime function are passed to the
        //    callback callee.
        Fn->addMetadata(
            LLVMContext::MD_callback,
            *MDNode::get(Ctx, {MDB.createCallbackEncoding(
                                  2, {-1, -1}, /* VarArgsArePassed */ true)}));
      }
    }
 
    LLVM_DEBUG(dbgs() << "Created OpenMP runtime function " << Fn->getName()
                      << " with type " << *Fn->getFunctionType() << "\n");
    addAttributes(FnID, *Fn);
 
  } else {
    LLVM_DEBUG(dbgs() << "Found OpenMP runtime function " << Fn->getName()
                      << " with type " << *Fn->getFunctionType() << "\n");
  }
 
  assert(Fn && "Failed to create OpenMP runtime function");
 
  // Cast the function to the expected type if necessary
  Constant *C = ConstantExpr::getBitCast(Fn, FnTy->getPointerTo());
  return {FnTy, C};
}
 
Function *OpenMPIRBuilder::getOrCreateRuntimeFunctionPtr(RuntimeFunction FnID) {
  FunctionCallee RTLFn = getOrCreateRuntimeFunction(M, FnID);
  auto *Fn = dyn_cast<llvm::Function>(RTLFn.getCallee());
  assert(Fn && "Failed to create OpenMP runtime function pointer");
  return Fn;
}
 
void OpenMPIRBuilder::initialize() { initializeTypes(M); }
 
void OpenMPIRBuilder::finalize(Function *Fn) {
  SmallPtrSet<BasicBlock *, 32> ParallelRegionBlockSet;
  SmallVector<BasicBlock *, 32> Blocks;
  SmallVector<OutlineInfo, 16> DeferredOutlines;
  for (OutlineInfo &OI : OutlineInfos) {
    // Skip functions that have not finalized yet; may happen with nested
    // function generation.
    if (Fn && OI.getFunction() != Fn) {
      DeferredOutlines.push_back(OI);
      continue;
    }
 
    ParallelRegionBlockSet.clear();
    Blocks.clear();
    OI.collectBlocks(ParallelRegionBlockSet, Blocks);
 
    Function *OuterFn = OI.getFunction();
    CodeExtractorAnalysisCache CEAC(*OuterFn);
    CodeExtractor Extractor(Blocks, /* DominatorTree */ nullptr,
                            /* AggregateArgs */ true,
                            /* BlockFrequencyInfo */ nullptr,
                            /* BranchProbabilityInfo */ nullptr,
                            /* AssumptionCache */ nullptr,
                            /* AllowVarArgs */ true,
                            /* AllowAlloca */ true,
                            /* AllocaBlock*/ OI.OuterAllocaBB,
                            /* Suffix */ ".omp_par");
 
    LLVM_DEBUG(dbgs() << "Before     outlining: " << *OuterFn << "\n");
    LLVM_DEBUG(dbgs() << "Entry " << OI.EntryBB->getName()
                      << " Exit: " << OI.ExitBB->getName() << "\n");
    assert(Extractor.isEligible() &&
           "Expected OpenMP outlining to be possible!");
 
    for (auto *V : OI.ExcludeArgsFromAggregate)
      Extractor.excludeArgFromAggregate(V);
 
    Function *OutlinedFn = Extractor.extractCodeRegion(CEAC);
 
    LLVM_DEBUG(dbgs() << "After      outlining: " << *OuterFn << "\n");
    LLVM_DEBUG(dbgs() << "   Outlined function: " << *OutlinedFn << "\n");
    assert(OutlinedFn->getReturnType()->isVoidTy() &&
           "OpenMP outlined functions should not return a value!");
 
    // For compability with the clang CG we move the outlined function after the
    // one with the parallel region.
    OutlinedFn->removeFromParent();
    M.getFunctionList().insertAfter(OuterFn->getIterator(), OutlinedFn);
 
    // Remove the artificial entry introduced by the extractor right away, we
    // made our own entry block after all.
    {
      BasicBlock &ArtificialEntry = OutlinedFn->getEntryBlock();
      assert(ArtificialEntry.getUniqueSuccessor() == OI.EntryBB);
      assert(OI.EntryBB->getUniquePredecessor() == &ArtificialEntry);
      // Move instructions from the to-be-deleted ArtificialEntry to the entry
      // basic block of the parallel region. CodeExtractor generates
      // instructions to unwrap the aggregate argument and may sink
      // allocas/bitcasts for values that are solely used in the outlined region
      // and do not escape.
      assert(!ArtificialEntry.empty() &&
             "Expected instructions to add in the outlined region entry");
      for (BasicBlock::reverse_iterator It = ArtificialEntry.rbegin(),
                                        End = ArtificialEntry.rend();
           It != End;) {
        Instruction &I = *It;
        It++;
 
        if (I.isTerminator())
          continue;
 
        I.moveBefore(*OI.EntryBB, OI.EntryBB->getFirstInsertionPt());
      }
 
      OI.EntryBB->moveBefore(&ArtificialEntry);
      ArtificialEntry.eraseFromParent();
    }
    assert(&OutlinedFn->getEntryBlock() == OI.EntryBB);
    assert(OutlinedFn && OutlinedFn->getNumUses() == 1);
 
    // Run a user callback, e.g. to add attributes.
    if (OI.PostOutlineCB)
      OI.PostOutlineCB(*OutlinedFn);
  }
 
  // Remove work items that have been completed.
  OutlineInfos = std::move(DeferredOutlines);
}
 
OpenMPIRBuilder::~OpenMPIRBuilder() {
  assert(OutlineInfos.empty() && "There must be no outstanding outlinings");
}
 
GlobalValue *OpenMPIRBuilder::createGlobalFlag(unsigned Value, StringRef Name) {
  IntegerType *I32Ty = Type::getInt32Ty(M.getContext());
  auto *GV =
      new GlobalVariable(M, I32Ty,
                         /* isConstant = */ true, GlobalValue::WeakODRLinkage,
                         ConstantInt::get(I32Ty, Value), Name);
  GV->setVisibility(GlobalValue::HiddenVisibility);
 
  return GV;
}
 
Constant *OpenMPIRBuilder::getOrCreateIdent(Constant *SrcLocStr,
                                            uint32_t SrcLocStrSize,
                                            IdentFlag LocFlags,
                                            unsigned Reserve2Flags) {
  // Enable "C-mode".
  LocFlags |= OMP_IDENT_FLAG_KMPC;
 
  Constant *&Ident =
      IdentMap[{SrcLocStr, uint64_t(LocFlags) << 31 | Reserve2Flags}];
  if (!Ident) {
    Constant *I32Null = ConstantInt::getNullValue(Int32);
    Constant *IdentData[] = {I32Null,
                             ConstantInt::get(Int32, uint32_t(LocFlags)),
                             ConstantInt::get(Int32, Reserve2Flags),
                             ConstantInt::get(Int32, SrcLocStrSize), SrcLocStr};
    Constant *Initializer =
        ConstantStruct::get(OpenMPIRBuilder::Ident, IdentData);
 
    // Look for existing encoding of the location + flags, not needed but
    // minimizes the difference to the existing solution while we transition.
    for (GlobalVariable &GV : M.globals())
      if (GV.getValueType() == OpenMPIRBuilder::Ident && GV.hasInitializer())
        if (GV.getInitializer() == Initializer)
          Ident = &GV;
 
    if (!Ident) {
      auto *GV = new GlobalVariable(
          M, OpenMPIRBuilder::Ident,
          /* isConstant = */ true, GlobalValue::PrivateLinkage, Initializer, "",
          nullptr, GlobalValue::NotThreadLocal,
          M.getDataLayout().getDefaultGlobalsAddressSpace());
      GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
      GV->setAlignment(Align(8));
      Ident = GV;
    }
  }
 
  return ConstantExpr::getPointerBitCastOrAddrSpaceCast(Ident, IdentPtr);
}
 
Constant *OpenMPIRBuilder::getOrCreateSrcLocStr(StringRef LocStr,
                                                uint32_t &SrcLocStrSize) {
  SrcLocStrSize = LocStr.size();
  Constant *&SrcLocStr = SrcLocStrMap[LocStr];
  if (!SrcLocStr) {
    Constant *Initializer =
        ConstantDataArray::getString(M.getContext(), LocStr);
 
    // Look for existing encoding of the location, not needed but minimizes the
    // difference to the existing solution while we transition.
    for (GlobalVariable &GV : M.globals())
      if (GV.isConstant() && GV.hasInitializer() &&
          GV.getInitializer() == Initializer)
        return SrcLocStr = ConstantExpr::getPointerCast(&GV, Int8Ptr);
 
    SrcLocStr = Builder.CreateGlobalStringPtr(LocStr, /* Name */ "",
                                              /* AddressSpace */ 0, &M);
  }
  return SrcLocStr;
}
 
Constant *OpenMPIRBuilder::getOrCreateSrcLocStr(StringRef FunctionName,
                                                StringRef FileName,
                                                unsigned Line, unsigned Column,
                                                uint32_t &SrcLocStrSize) {
  SmallString<128> Buffer;
  Buffer.push_back(';');
  Buffer.append(FileName);
  Buffer.push_back(';');
  Buffer.append(FunctionName);
  Buffer.push_back(';');
  Buffer.append(std::to_string(Line));
  Buffer.push_back(';');
  Buffer.append(std::to_string(Column));
  Buffer.push_back(';');
  Buffer.push_back(';');
  return getOrCreateSrcLocStr(Buffer.str(), SrcLocStrSize);
}
 
Constant *
OpenMPIRBuilder::getOrCreateDefaultSrcLocStr(uint32_t &SrcLocStrSize) {
  StringRef UnknownLoc = ";unknown;unknown;0;0;;";
  return getOrCreateSrcLocStr(UnknownLoc, SrcLocStrSize);
}
 
Constant *OpenMPIRBuilder::getOrCreateSrcLocStr(DebugLoc DL,
                                                uint32_t &SrcLocStrSize,
                                                Function *F) {
  DILocation *DIL = DL.get();
  if (!DIL)
    return getOrCreateDefaultSrcLocStr(SrcLocStrSize);
  StringRef FileName = M.getName();
  if (DIFile *DIF = DIL->getFile())
    if (std::optional<StringRef> Source = DIF->getSource())
      FileName = *Source;
  StringRef Function = DIL->getScope()->getSubprogram()->getName();
  if (Function.empty() && F)
    Function = F->getName();
  return getOrCreateSrcLocStr(Function, FileName, DIL->getLine(),
                              DIL->getColumn(), SrcLocStrSize);
}
 
Constant *OpenMPIRBuilder::getOrCreateSrcLocStr(const LocationDescription &Loc,
                                                uint32_t &SrcLocStrSize) {
  return getOrCreateSrcLocStr(Loc.DL, SrcLocStrSize,
                              Loc.IP.getBlock()->getParent());
}
 
Value *OpenMPIRBuilder::getOrCreateThreadID(Value *Ident) {
  return Builder.CreateCall(
      getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_global_thread_num), Ident,
      "omp_global_thread_num");
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createBarrier(const LocationDescription &Loc, Directive DK,
                               bool ForceSimpleCall, bool CheckCancelFlag) {
  if (!updateToLocation(Loc))
    return Loc.IP;
  return emitBarrierImpl(Loc, DK, ForceSimpleCall, CheckCancelFlag);
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::emitBarrierImpl(const LocationDescription &Loc, Directive Kind,
                                 bool ForceSimpleCall, bool CheckCancelFlag) {
  // Build call __kmpc_cancel_barrier(loc, thread_id) or
  //            __kmpc_barrier(loc, thread_id);
 
  IdentFlag BarrierLocFlags;
  switch (Kind) {
  case OMPD_for:
    BarrierLocFlags = OMP_IDENT_FLAG_BARRIER_IMPL_FOR;
    break;
  case OMPD_sections:
    BarrierLocFlags = OMP_IDENT_FLAG_BARRIER_IMPL_SECTIONS;
    break;
  case OMPD_single:
    BarrierLocFlags = OMP_IDENT_FLAG_BARRIER_IMPL_SINGLE;
    break;
  case OMPD_barrier:
    BarrierLocFlags = OMP_IDENT_FLAG_BARRIER_EXPL;
    break;
  default:
    BarrierLocFlags = OMP_IDENT_FLAG_BARRIER_IMPL;
    break;
  }
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Args[] = {
      getOrCreateIdent(SrcLocStr, SrcLocStrSize, BarrierLocFlags),
      getOrCreateThreadID(getOrCreateIdent(SrcLocStr, SrcLocStrSize))};
 
  // If we are in a cancellable parallel region, barriers are cancellation
  // points.
  // TODO: Check why we would force simple calls or to ignore the cancel flag.
  bool UseCancelBarrier =
      !ForceSimpleCall && isLastFinalizationInfoCancellable(OMPD_parallel);
 
  Value *Result =
      Builder.CreateCall(getOrCreateRuntimeFunctionPtr(
                             UseCancelBarrier ? OMPRTL___kmpc_cancel_barrier
                                              : OMPRTL___kmpc_barrier),
                         Args);
 
  if (UseCancelBarrier && CheckCancelFlag)
    emitCancelationCheckImpl(Result, OMPD_parallel);
 
  return Builder.saveIP();
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createCancel(const LocationDescription &Loc,
                              Value *IfCondition,
                              omp::Directive CanceledDirective) {
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  // LLVM utilities like blocks with terminators.
  auto *UI = Builder.CreateUnreachable();
 
  Instruction *ThenTI = UI, *ElseTI = nullptr;
  if (IfCondition)
    SplitBlockAndInsertIfThenElse(IfCondition, UI, &ThenTI, &ElseTI);
  Builder.SetInsertPoint(ThenTI);
 
  Value *CancelKind = nullptr;
  switch (CanceledDirective) {
#define OMP_CANCEL_KIND(Enum, Str, DirectiveEnum, Value)                       \
  case DirectiveEnum:                                                          \
    CancelKind = Builder.getInt32(Value);                                      \
    break;
#include "llvm/Frontend/OpenMP/OMPKinds.def"
  default:
    llvm_unreachable("Unknown cancel kind!");
  }
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *Args[] = {Ident, getOrCreateThreadID(Ident), CancelKind};
  Value *Result = Builder.CreateCall(
      getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_cancel), Args);
  auto ExitCB = [this, CanceledDirective, Loc](InsertPointTy IP) {
    if (CanceledDirective == OMPD_parallel) {
      IRBuilder<>::InsertPointGuard IPG(Builder);
      Builder.restoreIP(IP);
      createBarrier(LocationDescription(Builder.saveIP(), Loc.DL),
                    omp::Directive::OMPD_unknown, /* ForceSimpleCall */ false,
                    /* CheckCancelFlag */ false);
    }
  };
 
  // The actual cancel logic is shared with others, e.g., cancel_barriers.
  emitCancelationCheckImpl(Result, CanceledDirective, ExitCB);
 
  // Update the insertion point and remove the terminator we introduced.
  Builder.SetInsertPoint(UI->getParent());
  UI->eraseFromParent();
 
  return Builder.saveIP();
}
 
void OpenMPIRBuilder::emitOffloadingEntry(Constant *Addr, StringRef Name,
                                          uint64_t Size, int32_t Flags,
                                          StringRef SectionName) {
  Type *Int8PtrTy = Type::getInt8PtrTy(M.getContext());
  Type *Int32Ty = Type::getInt32Ty(M.getContext());
  Type *SizeTy = M.getDataLayout().getIntPtrType(M.getContext());
 
  Constant *AddrName = ConstantDataArray::getString(M.getContext(), Name);
 
  // Create the constant string used to look up the symbol in the device.
  auto *Str =
      new llvm::GlobalVariable(M, AddrName->getType(), /*isConstant=*/true,
                               llvm::GlobalValue::InternalLinkage, AddrName,
                               ".omp_offloading.entry_name");
  Str->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
 
  // Construct the offloading entry.
  Constant *EntryData[] = {
      ConstantExpr::getPointerBitCastOrAddrSpaceCast(Addr, Int8PtrTy),
      ConstantExpr::getPointerBitCastOrAddrSpaceCast(Str, Int8PtrTy),
      ConstantInt::get(SizeTy, Size),
      ConstantInt::get(Int32Ty, Flags),
      ConstantInt::get(Int32Ty, 0),
  };
  Constant *EntryInitializer =
      ConstantStruct::get(OpenMPIRBuilder::OffloadEntry, EntryData);
 
  auto *Entry = new GlobalVariable(
      M, OpenMPIRBuilder::OffloadEntry,
      /* isConstant = */ true, GlobalValue::WeakAnyLinkage, EntryInitializer,
      ".omp_offloading.entry." + Name, nullptr, GlobalValue::NotThreadLocal,
      M.getDataLayout().getDefaultGlobalsAddressSpace());
 
  // The entry has to be created in the section the linker expects it to be.
  Entry->setSection(SectionName);
  Entry->setAlignment(Align(1));
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::emitTargetKernel(
    const LocationDescription &Loc, InsertPointTy AllocaIP, Value *&Return,
    Value *Ident, Value *DeviceID, Value *NumTeams, Value *NumThreads,
    Value *HostPtr, ArrayRef<Value *> KernelArgs) {
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  Builder.restoreIP(AllocaIP);
  auto *KernelArgsPtr =
      Builder.CreateAlloca(OpenMPIRBuilder::KernelArgs, nullptr, "kernel_args");
  Builder.restoreIP(Loc.IP);
 
  for (unsigned I = 0, Size = KernelArgs.size(); I != Size; ++I) {
    llvm::Value *Arg =
        Builder.CreateStructGEP(OpenMPIRBuilder::KernelArgs, KernelArgsPtr, I);
    Builder.CreateAlignedStore(
        KernelArgs[I], Arg,
        M.getDataLayout().getPrefTypeAlign(KernelArgs[I]->getType()));
  }
 
  SmallVector<Value *> OffloadingArgs{Ident,      DeviceID, NumTeams,
                                      NumThreads, HostPtr,  KernelArgsPtr};
 
  Return = Builder.CreateCall(
      getOrCreateRuntimeFunction(M, OMPRTL___tgt_target_kernel),
      OffloadingArgs);
 
  return Builder.saveIP();
}
 
void OpenMPIRBuilder::emitCancelationCheckImpl(Value *CancelFlag,
                                               omp::Directive CanceledDirective,
                                               FinalizeCallbackTy ExitCB) {
  assert(isLastFinalizationInfoCancellable(CanceledDirective) &&
         "Unexpected cancellation!");
 
  // For a cancel barrier we create two new blocks.
  BasicBlock *BB = Builder.GetInsertBlock();
  BasicBlock *NonCancellationBlock;
  if (Builder.GetInsertPoint() == BB->end()) {
    // TODO: This branch will not be needed once we moved to the
    // OpenMPIRBuilder codegen completely.
    NonCancellationBlock = BasicBlock::Create(
        BB->getContext(), BB->getName() + ".cont", BB->getParent());
  } else {
    NonCancellationBlock = SplitBlock(BB, &*Builder.GetInsertPoint());
    BB->getTerminator()->eraseFromParent();
    Builder.SetInsertPoint(BB);
  }
  BasicBlock *CancellationBlock = BasicBlock::Create(
      BB->getContext(), BB->getName() + ".cncl", BB->getParent());
 
  // Jump to them based on the return value.
  Value *Cmp = Builder.CreateIsNull(CancelFlag);
  Builder.CreateCondBr(Cmp, NonCancellationBlock, CancellationBlock,
                       /* TODO weight */ nullptr, nullptr);
 
  // From the cancellation block we finalize all variables and go to the
  // post finalization block that is known to the FiniCB callback.
  Builder.SetInsertPoint(CancellationBlock);
  if (ExitCB)
    ExitCB(Builder.saveIP());
  auto &FI = FinalizationStack.back();
  FI.FiniCB(Builder.saveIP());
 
  // The continuation block is where code generation continues.
  Builder.SetInsertPoint(NonCancellationBlock, NonCancellationBlock->begin());
}
 
IRBuilder<>::InsertPoint OpenMPIRBuilder::createParallel(
    const LocationDescription &Loc, InsertPointTy OuterAllocaIP,
    BodyGenCallbackTy BodyGenCB, PrivatizeCallbackTy PrivCB,
    FinalizeCallbackTy FiniCB, Value *IfCondition, Value *NumThreads,
    omp::ProcBindKind ProcBind, bool IsCancellable) {
  assert(!isConflictIP(Loc.IP, OuterAllocaIP) && "IPs must not be ambiguous");
 
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadID = getOrCreateThreadID(Ident);
 
  if (NumThreads) {
    // Build call __kmpc_push_num_threads(&Ident, global_tid, num_threads)
    Value *Args[] = {
        Ident, ThreadID,
        Builder.CreateIntCast(NumThreads, Int32, /*isSigned*/ false)};
    Builder.CreateCall(
        getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_push_num_threads), Args);
  }
 
  if (ProcBind != OMP_PROC_BIND_default) {
    // Build call __kmpc_push_proc_bind(&Ident, global_tid, proc_bind)
    Value *Args[] = {
        Ident, ThreadID,
        ConstantInt::get(Int32, unsigned(ProcBind), /*isSigned=*/true)};
    Builder.CreateCall(
        getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_push_proc_bind), Args);
  }
 
  BasicBlock *InsertBB = Builder.GetInsertBlock();
  Function *OuterFn = InsertBB->getParent();
 
  // Save the outer alloca block because the insertion iterator may get
  // invalidated and we still need this later.
  BasicBlock *OuterAllocaBlock = OuterAllocaIP.getBlock();
 
  // Vector to remember instructions we used only during the modeling but which
  // we want to delete at the end.
  SmallVector<Instruction *, 4> ToBeDeleted;
 
  // Change the location to the outer alloca insertion point to create and
  // initialize the allocas we pass into the parallel region.
  Builder.restoreIP(OuterAllocaIP);
  AllocaInst *TIDAddr = Builder.CreateAlloca(Int32, nullptr, "tid.addr");
  AllocaInst *ZeroAddr = Builder.CreateAlloca(Int32, nullptr, "zero.addr");
 
  // We only need TIDAddr and ZeroAddr for modeling purposes to get the
  // associated arguments in the outlined function, so we delete them later.
  ToBeDeleted.push_back(TIDAddr);
  ToBeDeleted.push_back(ZeroAddr);
 
  // Create an artificial insertion point that will also ensure the blocks we
  // are about to split are not degenerated.
  auto *UI = new UnreachableInst(Builder.getContext(), InsertBB);
 
  BasicBlock *EntryBB = UI->getParent();
  BasicBlock *PRegEntryBB = EntryBB->splitBasicBlock(UI, "omp.par.entry");
  BasicBlock *PRegBodyBB = PRegEntryBB->splitBasicBlock(UI, "omp.par.region");
  BasicBlock *PRegPreFiniBB =
      PRegBodyBB->splitBasicBlock(UI, "omp.par.pre_finalize");
  BasicBlock *PRegExitBB = PRegPreFiniBB->splitBasicBlock(UI, "omp.par.exit");
 
  auto FiniCBWrapper = [&](InsertPointTy IP) {
    // Hide "open-ended" blocks from the given FiniCB by setting the right jump
    // target to the region exit block.
    if (IP.getBlock()->end() == IP.getPoint()) {
      IRBuilder<>::InsertPointGuard IPG(Builder);
      Builder.restoreIP(IP);
      Instruction *I = Builder.CreateBr(PRegExitBB);
      IP = InsertPointTy(I->getParent(), I->getIterator());
    }
    assert(IP.getBlock()->getTerminator()->getNumSuccessors() == 1 &&
           IP.getBlock()->getTerminator()->getSuccessor(0) == PRegExitBB &&
           "Unexpected insertion point for finalization call!");
    return FiniCB(IP);
  };
 
  FinalizationStack.push_back({FiniCBWrapper, OMPD_parallel, IsCancellable});
 
  // Generate the privatization allocas in the block that will become the entry
  // of the outlined function.
  Builder.SetInsertPoint(PRegEntryBB->getTerminator());
  InsertPointTy InnerAllocaIP = Builder.saveIP();
 
  AllocaInst *PrivTIDAddr =
      Builder.CreateAlloca(Int32, nullptr, "tid.addr.local");
  Instruction *PrivTID = Builder.CreateLoad(Int32, PrivTIDAddr, "tid");
 
  // Add some fake uses for OpenMP provided arguments.
  ToBeDeleted.push_back(Builder.CreateLoad(Int32, TIDAddr, "tid.addr.use"));
  Instruction *ZeroAddrUse =
      Builder.CreateLoad(Int32, ZeroAddr, "zero.addr.use");
  ToBeDeleted.push_back(ZeroAddrUse);
 
  // EntryBB
  //   |
  //   V
  // PRegionEntryBB         <- Privatization allocas are placed here.
  //   |
  //   V
  // PRegionBodyBB          <- BodeGen is invoked here.
  //   |
  //   V
  // PRegPreFiniBB          <- The block we will start finalization from.
  //   |
  //   V
  // PRegionExitBB          <- A common exit to simplify block collection.
  //
 
  LLVM_DEBUG(dbgs() << "Before body codegen: " << *OuterFn << "\n");
 
  // Let the caller create the body.
  assert(BodyGenCB && "Expected body generation callback!");
  InsertPointTy CodeGenIP(PRegBodyBB, PRegBodyBB->begin());
  BodyGenCB(InnerAllocaIP, CodeGenIP);
 
  LLVM_DEBUG(dbgs() << "After  body codegen: " << *OuterFn << "\n");
  FunctionCallee RTLFn;
  if (IfCondition)
    RTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_fork_call_if);
  else
    RTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_fork_call);
 
  if (auto *F = dyn_cast<llvm::Function>(RTLFn.getCallee())) {
    if (!F->hasMetadata(llvm::LLVMContext::MD_callback)) {
      llvm::LLVMContext &Ctx = F->getContext();
      MDBuilder MDB(Ctx);
      // Annotate the callback behavior of the __kmpc_fork_call:
      //  - The callback callee is argument number 2 (microtask).
      //  - The first two arguments of the callback callee are unknown (-1).
      //  - All variadic arguments to the __kmpc_fork_call are passed to the
      //    callback callee.
      F->addMetadata(
          llvm::LLVMContext::MD_callback,
          *llvm::MDNode::get(
              Ctx, {MDB.createCallbackEncoding(2, {-1, -1},
                                               /* VarArgsArePassed */ true)}));
    }
  }
 
  OutlineInfo OI;
  OI.PostOutlineCB = [=](Function &OutlinedFn) {
    // Add some known attributes.
    OutlinedFn.addParamAttr(0, Attribute::NoAlias);
    OutlinedFn.addParamAttr(1, Attribute::NoAlias);
    OutlinedFn.addFnAttr(Attribute::NoUnwind);
    OutlinedFn.addFnAttr(Attribute::NoRecurse);
 
    assert(OutlinedFn.arg_size() >= 2 &&
           "Expected at least tid and bounded tid as arguments");
    unsigned NumCapturedVars =
        OutlinedFn.arg_size() - /* tid & bounded tid */ 2;
 
    CallInst *CI = cast<CallInst>(OutlinedFn.user_back());
    CI->getParent()->setName("omp_parallel");
    Builder.SetInsertPoint(CI);
 
    // Build call __kmpc_fork_call[_if](Ident, n, microtask, var1, .., varn);
    Value *ForkCallArgs[] = {
        Ident, Builder.getInt32(NumCapturedVars),
        Builder.CreateBitCast(&OutlinedFn, ParallelTaskPtr)};
 
    SmallVector<Value *, 16> RealArgs;
    RealArgs.append(std::begin(ForkCallArgs), std::end(ForkCallArgs));
    if (IfCondition) {
      Value *Cond = Builder.CreateSExtOrTrunc(IfCondition,
                                              Type::getInt32Ty(M.getContext()));
      RealArgs.push_back(Cond);
    }
    RealArgs.append(CI->arg_begin() + /* tid & bound tid */ 2, CI->arg_end());
 
    // __kmpc_fork_call_if always expects a void ptr as the last argument
    // If there are no arguments, pass a null pointer.
    auto PtrTy = Type::getInt8PtrTy(M.getContext());
    if (IfCondition && NumCapturedVars == 0) {
      llvm::Value *Void = ConstantPointerNull::get(PtrTy);
      RealArgs.push_back(Void);
    }
    if (IfCondition && RealArgs.back()->getType() != PtrTy)
      RealArgs.back() = Builder.CreateBitCast(RealArgs.back(), PtrTy);
 
    Builder.CreateCall(RTLFn, RealArgs);
 
    LLVM_DEBUG(dbgs() << "With fork_call placed: "
                      << *Builder.GetInsertBlock()->getParent() << "\n");
 
    InsertPointTy ExitIP(PRegExitBB, PRegExitBB->end());
 
    // Initialize the local TID stack location with the argument value.
    Builder.SetInsertPoint(PrivTID);
    Function::arg_iterator OutlinedAI = OutlinedFn.arg_begin();
    Builder.CreateStore(Builder.CreateLoad(Int32, OutlinedAI), PrivTIDAddr);
 
    CI->eraseFromParent();
 
    for (Instruction *I : ToBeDeleted)
      I->eraseFromParent();
  };
 
  // Adjust the finalization stack, verify the adjustment, and call the
  // finalize function a last time to finalize values between the pre-fini
  // block and the exit block if we left the parallel "the normal way".
  auto FiniInfo = FinalizationStack.pop_back_val();
  (void)FiniInfo;
  assert(FiniInfo.DK == OMPD_parallel &&
         "Unexpected finalization stack state!");
 
  Instruction *PRegPreFiniTI = PRegPreFiniBB->getTerminator();
 
  InsertPointTy PreFiniIP(PRegPreFiniBB, PRegPreFiniTI->getIterator());
  FiniCB(PreFiniIP);
 
  OI.OuterAllocaBB = OuterAllocaBlock;
  OI.EntryBB = PRegEntryBB;
  OI.ExitBB = PRegExitBB;
 
  SmallPtrSet<BasicBlock *, 32> ParallelRegionBlockSet;
  SmallVector<BasicBlock *, 32> Blocks;
  OI.collectBlocks(ParallelRegionBlockSet, Blocks);
 
  // Ensure a single exit node for the outlined region by creating one.
  // We might have multiple incoming edges to the exit now due to finalizations,
  // e.g., cancel calls that cause the control flow to leave the region.
  BasicBlock *PRegOutlinedExitBB = PRegExitBB;
  PRegExitBB = SplitBlock(PRegExitBB, &*PRegExitBB->getFirstInsertionPt());
  PRegOutlinedExitBB->setName("omp.par.outlined.exit");
  Blocks.push_back(PRegOutlinedExitBB);
 
  CodeExtractorAnalysisCache CEAC(*OuterFn);
  CodeExtractor Extractor(Blocks, /* DominatorTree */ nullptr,
                          /* AggregateArgs */ false,
                          /* BlockFrequencyInfo */ nullptr,
                          /* BranchProbabilityInfo */ nullptr,
                          /* AssumptionCache */ nullptr,
                          /* AllowVarArgs */ true,
                          /* AllowAlloca */ true,
                          /* AllocationBlock */ OuterAllocaBlock,
                          /* Suffix */ ".omp_par");
 
  // Find inputs to, outputs from the code region.
  BasicBlock *CommonExit = nullptr;
  SetVector<Value *> Inputs, Outputs, SinkingCands, HoistingCands;
  Extractor.findAllocas(CEAC, SinkingCands, HoistingCands, CommonExit);
  Extractor.findInputsOutputs(Inputs, Outputs, SinkingCands);
 
  LLVM_DEBUG(dbgs() << "Before privatization: " << *OuterFn << "\n");
 
  FunctionCallee TIDRTLFn =
      getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_global_thread_num);
 
  auto PrivHelper = [&](Value &V) {
    if (&V == TIDAddr || &V == ZeroAddr) {
      OI.ExcludeArgsFromAggregate.push_back(&V);
      return;
    }
 
    SetVector<Use *> Uses;
    for (Use &U : V.uses())
      if (auto *UserI = dyn_cast<Instruction>(U.getUser()))
        if (ParallelRegionBlockSet.count(UserI->getParent()))
          Uses.insert(&U);
 
    // __kmpc_fork_call expects extra arguments as pointers. If the input
    // already has a pointer type, everything is fine. Otherwise, store the
    // value onto stack and load it back inside the to-be-outlined region. This
    // will ensure only the pointer will be passed to the function.
    // FIXME: if there are more than 15 trailing arguments, they must be
    // additionally packed in a struct.
    Value *Inner = &V;
    if (!V.getType()->isPointerTy()) {
      IRBuilder<>::InsertPointGuard Guard(Builder);
      LLVM_DEBUG(llvm::dbgs() << "Forwarding input as pointer: " << V << "\n");
 
      Builder.restoreIP(OuterAllocaIP);
      Value *Ptr =
          Builder.CreateAlloca(V.getType(), nullptr, V.getName() + ".reloaded");
 
      // Store to stack at end of the block that currently branches to the entry
      // block of the to-be-outlined region.
      Builder.SetInsertPoint(InsertBB,
                             InsertBB->getTerminator()->getIterator());
      Builder.CreateStore(&V, Ptr);
 
      // Load back next to allocations in the to-be-outlined region.
      Builder.restoreIP(InnerAllocaIP);
      Inner = Builder.CreateLoad(V.getType(), Ptr);
    }
 
    Value *ReplacementValue = nullptr;
    CallInst *CI = dyn_cast<CallInst>(&V);
    if (CI && CI->getCalledFunction() == TIDRTLFn.getCallee()) {
      ReplacementValue = PrivTID;
    } else {
      Builder.restoreIP(
          PrivCB(InnerAllocaIP, Builder.saveIP(), V, *Inner, ReplacementValue));
      assert(ReplacementValue &&
             "Expected copy/create callback to set replacement value!");
      if (ReplacementValue == &V)
        return;
    }
 
    for (Use *UPtr : Uses)
      UPtr->set(ReplacementValue);
  };
 
  // Reset the inner alloca insertion as it will be used for loading the values
  // wrapped into pointers before passing them into the to-be-outlined region.
  // Configure it to insert immediately after the fake use of zero address so
  // that they are available in the generated body and so that the
  // OpenMP-related values (thread ID and zero address pointers) remain leading
  // in the argument list.
  InnerAllocaIP = IRBuilder<>::InsertPoint(
      ZeroAddrUse->getParent(), ZeroAddrUse->getNextNode()->getIterator());
 
  // Reset the outer alloca insertion point to the entry of the relevant block
  // in case it was invalidated.
  OuterAllocaIP = IRBuilder<>::InsertPoint(
      OuterAllocaBlock, OuterAllocaBlock->getFirstInsertionPt());
 
  for (Value *Input : Inputs) {
    LLVM_DEBUG(dbgs() << "Captured input: " << *Input << "\n");
    PrivHelper(*Input);
  }
  LLVM_DEBUG({
    for (Value *Output : Outputs)
      LLVM_DEBUG(dbgs() << "Captured output: " << *Output << "\n");
  });
  assert(Outputs.empty() &&
         "OpenMP outlining should not produce live-out values!");
 
  LLVM_DEBUG(dbgs() << "After  privatization: " << *OuterFn << "\n");
  LLVM_DEBUG({
    for (auto *BB : Blocks)
      dbgs() << " PBR: " << BB->getName() << "\n";
  });
 
  // Register the outlined info.
  addOutlineInfo(std::move(OI));
 
  InsertPointTy AfterIP(UI->getParent(), UI->getParent()->end());
  UI->eraseFromParent();
 
  return AfterIP;
}
 
void OpenMPIRBuilder::emitFlush(const LocationDescription &Loc) {
  // Build call void __kmpc_flush(ident_t *loc)
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Args[] = {getOrCreateIdent(SrcLocStr, SrcLocStrSize)};
 
  Builder.CreateCall(getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_flush), Args);
}
 
void OpenMPIRBuilder::createFlush(const LocationDescription &Loc) {
  if (!updateToLocation(Loc))
    return;
  emitFlush(Loc);
}
 
void OpenMPIRBuilder::emitTaskwaitImpl(const LocationDescription &Loc) {
  // Build call kmp_int32 __kmpc_omp_taskwait(ident_t *loc, kmp_int32
  // global_tid);
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *Args[] = {Ident, getOrCreateThreadID(Ident)};
 
  // Ignore return result until untied tasks are supported.
  Builder.CreateCall(getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_omp_taskwait),
                     Args);
}
 
void OpenMPIRBuilder::createTaskwait(const LocationDescription &Loc) {
  if (!updateToLocation(Loc))
    return;
  emitTaskwaitImpl(Loc);
}
 
void OpenMPIRBuilder::emitTaskyieldImpl(const LocationDescription &Loc) {
  // Build call __kmpc_omp_taskyield(loc, thread_id, 0);
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Constant *I32Null = ConstantInt::getNullValue(Int32);
  Value *Args[] = {Ident, getOrCreateThreadID(Ident), I32Null};
 
  Builder.CreateCall(getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_omp_taskyield),
                     Args);
}
 
void OpenMPIRBuilder::createTaskyield(const LocationDescription &Loc) {
  if (!updateToLocation(Loc))
    return;
  emitTaskyieldImpl(Loc);
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createTask(const LocationDescription &Loc,
                            InsertPointTy AllocaIP, BodyGenCallbackTy BodyGenCB,
                            bool Tied, Value *Final, Value *IfCondition,
                            SmallVector<DependData> Dependencies) {
  if (!updateToLocation(Loc))
    return InsertPointTy();
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  // The current basic block is split into four basic blocks. After outlining,
  // they will be mapped as follows:
  // ```
  // def current_fn() {
  //   current_basic_block:
  //     br label %task.exit
  //   task.exit:
  //     ; instructions after task
  // }
  // def outlined_fn() {
  //   task.alloca:
  //     br label %task.body
  //   task.body:
  //     ret void
  // }
  // ```
  BasicBlock *TaskExitBB = splitBB(Builder, /*CreateBranch=*/true, "task.exit");
  BasicBlock *TaskBodyBB = splitBB(Builder, /*CreateBranch=*/true, "task.body");
  BasicBlock *TaskAllocaBB =
      splitBB(Builder, /*CreateBranch=*/true, "task.alloca");
 
  OutlineInfo OI;
  OI.EntryBB = TaskAllocaBB;
  OI.OuterAllocaBB = AllocaIP.getBlock();
  OI.ExitBB = TaskExitBB;
  OI.PostOutlineCB = [this, Ident, Tied, Final, IfCondition,
                      Dependencies](Function &OutlinedFn) {
    // The input IR here looks like the following-
    // ```
    // func @current_fn() {
    //   outlined_fn(%args)
    // }
    // func @outlined_fn(%args) { ... }
    // ```
    //
    // This is changed to the following-
    //
    // ```
    // func @current_fn() {
    //   runtime_call(..., wrapper_fn, ...)
    // }
    // func @wrapper_fn(..., %args) {
    //   outlined_fn(%args)
    // }
    // func @outlined_fn(%args) { ... }
    // ```
 
    // The stale call instruction will be replaced with a new call instruction
    // for runtime call with a wrapper function.
    assert(OutlinedFn.getNumUses() == 1 &&
           "there must be a single user for the outlined function");
    CallInst *StaleCI = cast<CallInst>(OutlinedFn.user_back());
 
    // HasTaskData is true if any variables are captured in the outlined region,
    // false otherwise.
    bool HasTaskData = StaleCI->arg_size() > 0;
    Builder.SetInsertPoint(StaleCI);
 
    // Gather the arguments for emitting the runtime call for
    // @__kmpc_omp_task_alloc
    Function *TaskAllocFn =
        getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_omp_task_alloc);
 
    // Arguments - `loc_ref` (Ident) and `gtid` (ThreadID)
    // call.
    Value *ThreadID = getOrCreateThreadID(Ident);
 
    // Argument - `flags`
    // Task is tied iff (Flags & 1) == 1.
    // Task is untied iff (Flags & 1) == 0.
    // Task is final iff (Flags & 2) == 2.
    // Task is not final iff (Flags & 2) == 0.
    // TODO: Handle the other flags.
    Value *Flags = Builder.getInt32(Tied);
    if (Final) {
      Value *FinalFlag =
          Builder.CreateSelect(Final, Builder.getInt32(2), Builder.getInt32(0));
      Flags = Builder.CreateOr(FinalFlag, Flags);
    }
 
    // Argument - `sizeof_kmp_task_t` (TaskSize)
    // Tasksize refers to the size in bytes of kmp_task_t data structure
    // including private vars accessed in task.
    Value *TaskSize = Builder.getInt64(0);
    if (HasTaskData) {
      AllocaInst *ArgStructAlloca =
          dyn_cast<AllocaInst>(StaleCI->getArgOperand(0));
      assert(ArgStructAlloca &&
             "Unable to find the alloca instruction corresponding to arguments "
             "for extracted function");
      StructType *ArgStructType =
          dyn_cast<StructType>(ArgStructAlloca->getAllocatedType());
      assert(ArgStructType && "Unable to find struct type corresponding to "
                              "arguments for extracted function");
      TaskSize =
          Builder.getInt64(M.getDataLayout().getTypeStoreSize(ArgStructType));
    }
 
    // TODO: Argument - sizeof_shareds
 
    // Argument - task_entry (the wrapper function)
    // If the outlined function has some captured variables (i.e. HasTaskData is
    // true), then the wrapper function will have an additional argument (the
    // struct containing captured variables). Otherwise, no such argument will
    // be present.
    SmallVector<Type *> WrapperArgTys{Builder.getInt32Ty()};
    if (HasTaskData)
      WrapperArgTys.push_back(OutlinedFn.getArg(0)->getType());
    FunctionCallee WrapperFuncVal = M.getOrInsertFunction(
        (Twine(OutlinedFn.getName()) + ".wrapper").str(),
        FunctionType::get(Builder.getInt32Ty(), WrapperArgTys, false));
    Function *WrapperFunc = dyn_cast<Function>(WrapperFuncVal.getCallee());
    PointerType *WrapperFuncBitcastType =
        FunctionType::get(Builder.getInt32Ty(),
                          {Builder.getInt32Ty(), Builder.getInt8PtrTy()}, false)
            ->getPointerTo();
    Value *WrapperFuncBitcast =
        ConstantExpr::getBitCast(WrapperFunc, WrapperFuncBitcastType);
 
    // Emit the @__kmpc_omp_task_alloc runtime call
    // The runtime call returns a pointer to an area where the task captured
    // variables must be copied before the task is run (NewTaskData)
    CallInst *NewTaskData = Builder.CreateCall(
        TaskAllocFn,
        {/*loc_ref=*/Ident, /*gtid=*/ThreadID, /*flags=*/Flags,
         /*sizeof_task=*/TaskSize, /*sizeof_shared=*/Builder.getInt64(0),
         /*task_func=*/WrapperFuncBitcast});
 
    // Copy the arguments for outlined function
    if (HasTaskData) {
      Value *TaskData = StaleCI->getArgOperand(0);
      Align Alignment = TaskData->getPointerAlignment(M.getDataLayout());
      Builder.CreateMemCpy(NewTaskData, Alignment, TaskData, Alignment,
                           TaskSize);
    }
 
    Value *DepArrayPtr = nullptr;
    if (Dependencies.size()) {
      InsertPointTy OldIP = Builder.saveIP();
      Builder.SetInsertPoint(
          &OldIP.getBlock()->getParent()->getEntryBlock().back());
 
      Type *DepArrayTy = ArrayType::get(DependInfo, Dependencies.size());
      Value *DepArray =
          Builder.CreateAlloca(DepArrayTy, nullptr, ".dep.arr.addr");
 
      unsigned P = 0;
      for (const DependData &Dep : Dependencies) {
        Value *Base =
            Builder.CreateConstInBoundsGEP2_64(DepArrayTy, DepArray, 0, P);
        // Store the pointer to the variable
        Value *Addr = Builder.CreateStructGEP(
            DependInfo, Base,
            static_cast<unsigned int>(RTLDependInfoFields::BaseAddr));
        Value *DepValPtr =
            Builder.CreatePtrToInt(Dep.DepVal, Builder.getInt64Ty());
        Builder.CreateStore(DepValPtr, Addr);
        // Store the size of the variable
        Value *Size = Builder.CreateStructGEP(
            DependInfo, Base,
            static_cast<unsigned int>(RTLDependInfoFields::Len));
        Builder.CreateStore(Builder.getInt64(M.getDataLayout().getTypeStoreSize(
                                Dep.DepValueType)),
                            Size);
        // Store the dependency kind
        Value *Flags = Builder.CreateStructGEP(
            DependInfo, Base,
            static_cast<unsigned int>(RTLDependInfoFields::Flags));
        Builder.CreateStore(
            ConstantInt::get(Builder.getInt8Ty(),
                             static_cast<unsigned int>(Dep.DepKind)),
            Flags);
        ++P;
      }
 
      DepArrayPtr = Builder.CreateBitCast(DepArray, Builder.getInt8PtrTy());
      Builder.restoreIP(OldIP);
    }
 
    // In the presence of the `if` clause, the following IR is generated:
    //    ...
    //    %data = call @__kmpc_omp_task_alloc(...)
    //    br i1 %if_condition, label %then, label %else
    //  then:
    //    call @__kmpc_omp_task(...)
    //    br label %exit
    //  else:
    //    call @__kmpc_omp_task_begin_if0(...)
    //    call @wrapper_fn(...)
    //    call @__kmpc_omp_task_complete_if0(...)
    //    br label %exit
    //  exit:
    //    ...
    if (IfCondition) {
      // `SplitBlockAndInsertIfThenElse` requires the block to have a
      // terminator.
      BasicBlock *NewBasicBlock =
          splitBB(Builder, /*CreateBranch=*/true, "if.end");
      Instruction *IfTerminator =
          NewBasicBlock->getSinglePredecessor()->getTerminator();
      Instruction *ThenTI = IfTerminator, *ElseTI = nullptr;
      Builder.SetInsertPoint(IfTerminator);
      SplitBlockAndInsertIfThenElse(IfCondition, IfTerminator, &ThenTI,
                                    &ElseTI);
      Builder.SetInsertPoint(ElseTI);
      Function *TaskBeginFn =
          getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_omp_task_begin_if0);
      Function *TaskCompleteFn =
          getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_omp_task_complete_if0);
      Builder.CreateCall(TaskBeginFn, {Ident, ThreadID, NewTaskData});
      if (HasTaskData)
        Builder.CreateCall(WrapperFunc, {ThreadID, NewTaskData});
      else
        Builder.CreateCall(WrapperFunc, {ThreadID});
      Builder.CreateCall(TaskCompleteFn, {Ident, ThreadID, NewTaskData});
      Builder.SetInsertPoint(ThenTI);
    }
 
    if (Dependencies.size()) {
      Function *TaskFn =
          getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_omp_task_with_deps);
      Builder.CreateCall(
          TaskFn,
          {Ident, ThreadID, NewTaskData, Builder.getInt32(Dependencies.size()),
           DepArrayPtr, ConstantInt::get(Builder.getInt32Ty(), 0),
           ConstantPointerNull::get(Type::getInt8PtrTy(M.getContext()))});
 
    } else {
      // Emit the @__kmpc_omp_task runtime call to spawn the task
      Function *TaskFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_omp_task);
      Builder.CreateCall(TaskFn, {Ident, ThreadID, NewTaskData});
    }
 
    StaleCI->eraseFromParent();
 
    // Emit the body for wrapper function
    BasicBlock *WrapperEntryBB =
        BasicBlock::Create(M.getContext(), "", WrapperFunc);
    Builder.SetInsertPoint(WrapperEntryBB);
    if (HasTaskData)
      Builder.CreateCall(&OutlinedFn, {WrapperFunc->getArg(1)});
    else
      Builder.CreateCall(&OutlinedFn);
    Builder.CreateRet(Builder.getInt32(0));
  };
 
  addOutlineInfo(std::move(OI));
 
  InsertPointTy TaskAllocaIP =
      InsertPointTy(TaskAllocaBB, TaskAllocaBB->begin());
  InsertPointTy TaskBodyIP = InsertPointTy(TaskBodyBB, TaskBodyBB->begin());
  BodyGenCB(TaskAllocaIP, TaskBodyIP);
  Builder.SetInsertPoint(TaskExitBB, TaskExitBB->begin());
 
  return Builder.saveIP();
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createTaskgroup(const LocationDescription &Loc,
                                 InsertPointTy AllocaIP,
                                 BodyGenCallbackTy BodyGenCB) {
  if (!updateToLocation(Loc))
    return InsertPointTy();
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadID = getOrCreateThreadID(Ident);
 
  // Emit the @__kmpc_taskgroup runtime call to start the taskgroup
  Function *TaskgroupFn =
      getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_taskgroup);
  Builder.CreateCall(TaskgroupFn, {Ident, ThreadID});
 
  BasicBlock *TaskgroupExitBB = splitBB(Builder, true, "taskgroup.exit");
  BodyGenCB(AllocaIP, Builder.saveIP());
 
  Builder.SetInsertPoint(TaskgroupExitBB);
  // Emit the @__kmpc_end_taskgroup runtime call to end the taskgroup
  Function *EndTaskgroupFn =
      getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_end_taskgroup);
  Builder.CreateCall(EndTaskgroupFn, {Ident, ThreadID});
 
  return Builder.saveIP();
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::createSections(
    const LocationDescription &Loc, InsertPointTy AllocaIP,
    ArrayRef<StorableBodyGenCallbackTy> SectionCBs, PrivatizeCallbackTy PrivCB,
    FinalizeCallbackTy FiniCB, bool IsCancellable, bool IsNowait) {
  assert(!isConflictIP(AllocaIP, Loc.IP) && "Dedicated IP allocas required");
 
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  auto FiniCBWrapper = [&](InsertPointTy IP) {
    if (IP.getBlock()->end() != IP.getPoint())
      return FiniCB(IP);
    // This must be done otherwise any nested constructs using FinalizeOMPRegion
    // will fail because that function requires the Finalization Basic Block to
    // have a terminator, which is already removed by EmitOMPRegionBody.
    // IP is currently at cancelation block.
    // We need to backtrack to the condition block to fetch
    // the exit block and create a branch from cancelation
    // to exit block.
    IRBuilder<>::InsertPointGuard IPG(Builder);
    Builder.restoreIP(IP);
    auto *CaseBB = IP.getBlock()->getSinglePredecessor();
    auto *CondBB = CaseBB->getSinglePredecessor()->getSinglePredecessor();
    auto *ExitBB = CondBB->getTerminator()->getSuccessor(1);
    Instruction *I = Builder.CreateBr(ExitBB);
    IP = InsertPointTy(I->getParent(), I->getIterator());
    return FiniCB(IP);
  };
 
  FinalizationStack.push_back({FiniCBWrapper, OMPD_sections, IsCancellable});
 
  // Each section is emitted as a switch case
  // Each finalization callback is handled from clang.EmitOMPSectionDirective()
  // -> OMP.createSection() which generates the IR for each section
  // Iterate through all sections and emit a switch construct:
  // switch (IV) {
  //   case 0:
  //     <SectionStmt[0]>;
  //     break;
  // ...
  //   case <NumSection> - 1:
  //     <SectionStmt[<NumSection> - 1]>;
  //     break;
  // }
  // ...
  // section_loop.after:
  // <FiniCB>;
  auto LoopBodyGenCB = [&](InsertPointTy CodeGenIP, Value *IndVar) {
    Builder.restoreIP(CodeGenIP);
    BasicBlock *Continue =
        splitBBWithSuffix(Builder, /*CreateBranch=*/false, ".sections.after");
    Function *CurFn = Continue->getParent();
    SwitchInst *SwitchStmt = Builder.CreateSwitch(IndVar, Continue);
 
    unsigned CaseNumber = 0;
    for (auto SectionCB : SectionCBs) {
      BasicBlock *CaseBB = BasicBlock::Create(
          M.getContext(), "omp_section_loop.body.case", CurFn, Continue);
      SwitchStmt->addCase(Builder.getInt32(CaseNumber), CaseBB);
      Builder.SetInsertPoint(CaseBB);
      BranchInst *CaseEndBr = Builder.CreateBr(Continue);
      SectionCB(InsertPointTy(),
                {CaseEndBr->getParent(), CaseEndBr->getIterator()});
      CaseNumber++;
    }
    // remove the existing terminator from body BB since there can be no
    // terminators after switch/case
  };
  // Loop body ends here
  // LowerBound, UpperBound, and STride for createCanonicalLoop
  Type *I32Ty = Type::getInt32Ty(M.getContext());
  Value *LB = ConstantInt::get(I32Ty, 0);
  Value *UB = ConstantInt::get(I32Ty, SectionCBs.size());
  Value *ST = ConstantInt::get(I32Ty, 1);
  llvm::CanonicalLoopInfo *LoopInfo = createCanonicalLoop(
      Loc, LoopBodyGenCB, LB, UB, ST, true, false, AllocaIP, "section_loop");
  InsertPointTy AfterIP =
      applyStaticWorkshareLoop(Loc.DL, LoopInfo, AllocaIP, !IsNowait);
 
  // Apply the finalization callback in LoopAfterBB
  auto FiniInfo = FinalizationStack.pop_back_val();
  assert(FiniInfo.DK == OMPD_sections &&
         "Unexpected finalization stack state!");
  if (FinalizeCallbackTy &CB = FiniInfo.FiniCB) {
    Builder.restoreIP(AfterIP);
    BasicBlock *FiniBB =
        splitBBWithSuffix(Builder, /*CreateBranch=*/true, "sections.fini");
    CB(Builder.saveIP());
    AfterIP = {FiniBB, FiniBB->begin()};
  }
 
  return AfterIP;
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createSection(const LocationDescription &Loc,
                               BodyGenCallbackTy BodyGenCB,
                               FinalizeCallbackTy FiniCB) {
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  auto FiniCBWrapper = [&](InsertPointTy IP) {
    if (IP.getBlock()->end() != IP.getPoint())
      return FiniCB(IP);
    // This must be done otherwise any nested constructs using FinalizeOMPRegion
    // will fail because that function requires the Finalization Basic Block to
    // have a terminator, which is already removed by EmitOMPRegionBody.
    // IP is currently at cancelation block.
    // We need to backtrack to the condition block to fetch
    // the exit block and create a branch from cancelation
    // to exit block.
    IRBuilder<>::InsertPointGuard IPG(Builder);
    Builder.restoreIP(IP);
    auto *CaseBB = Loc.IP.getBlock();
    auto *CondBB = CaseBB->getSinglePredecessor()->getSinglePredecessor();
    auto *ExitBB = CondBB->getTerminator()->getSuccessor(1);
    Instruction *I = Builder.CreateBr(ExitBB);
    IP = InsertPointTy(I->getParent(), I->getIterator());
    return FiniCB(IP);
  };
 
  Directive OMPD = Directive::OMPD_sections;
  // Since we are using Finalization Callback here, HasFinalize
  // and IsCancellable have to be true
  return EmitOMPInlinedRegion(OMPD, nullptr, nullptr, BodyGenCB, FiniCBWrapper,
                              /*Conditional*/ false, /*hasFinalize*/ true,
                              /*IsCancellable*/ true);
}
 
/// Create a function with a unique name and a "void (i8*, i8*)" signature in
/// the given module and return it.
Function *getFreshReductionFunc(Module &M) {
  Type *VoidTy = Type::getVoidTy(M.getContext());
  Type *Int8PtrTy = Type::getInt8PtrTy(M.getContext());
  auto *FuncTy =
      FunctionType::get(VoidTy, {Int8PtrTy, Int8PtrTy}, /* IsVarArg */ false);
  return Function::Create(FuncTy, GlobalVariable::InternalLinkage,
                          M.getDataLayout().getDefaultGlobalsAddressSpace(),
                          ".omp.reduction.func", &M);
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::createReductions(
    const LocationDescription &Loc, InsertPointTy AllocaIP,
    ArrayRef<ReductionInfo> ReductionInfos, bool IsNoWait) {
  for (const ReductionInfo &RI : ReductionInfos) {
    (void)RI;
    assert(RI.Variable && "expected non-null variable");
    assert(RI.PrivateVariable && "expected non-null private variable");
    assert(RI.ReductionGen && "expected non-null reduction generator callback");
    assert(RI.Variable->getType() == RI.PrivateVariable->getType() &&
           "expected variables and their private equivalents to have the same "
           "type");
    assert(RI.Variable->getType()->isPointerTy() &&
           "expected variables to be pointers");
  }
 
  if (!updateToLocation(Loc))
    return InsertPointTy();
 
  BasicBlock *InsertBlock = Loc.IP.getBlock();
  BasicBlock *ContinuationBlock =
      InsertBlock->splitBasicBlock(Loc.IP.getPoint(), "reduce.finalize");
  InsertBlock->getTerminator()->eraseFromParent();
 
  // Create and populate array of type-erased pointers to private reduction
  // values.
  unsigned NumReductions = ReductionInfos.size();
  Type *RedArrayTy = ArrayType::get(Builder.getInt8PtrTy(), NumReductions);
  Builder.restoreIP(AllocaIP);
  Value *RedArray = Builder.CreateAlloca(RedArrayTy, nullptr, "red.array");
 
  Builder.SetInsertPoint(InsertBlock, InsertBlock->end());
 
  for (auto En : enumerate(ReductionInfos)) {
    unsigned Index = En.index();
    const ReductionInfo &RI = En.value();
    Value *RedArrayElemPtr = Builder.CreateConstInBoundsGEP2_64(
        RedArrayTy, RedArray, 0, Index, "red.array.elem." + Twine(Index));
    Value *Casted =
        Builder.CreateBitCast(RI.PrivateVariable, Builder.getInt8PtrTy(),
                              "private.red.var." + Twine(Index) + ".casted");
    Builder.CreateStore(Casted, RedArrayElemPtr);
  }
 
  // Emit a call to the runtime function that orchestrates the reduction.
  // Declare the reduction function in the process.
  Function *Func = Builder.GetInsertBlock()->getParent();
  Module *Module = Func->getParent();
  Value *RedArrayPtr =
      Builder.CreateBitCast(RedArray, Builder.getInt8PtrTy(), "red.array.ptr");
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  bool CanGenerateAtomic =
      llvm::all_of(ReductionInfos, [](const ReductionInfo &RI) {
        return RI.AtomicReductionGen;
      });
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize,
                                  CanGenerateAtomic
                                      ? IdentFlag::OMP_IDENT_FLAG_ATOMIC_REDUCE
                                      : IdentFlag(0));
  Value *ThreadId = getOrCreateThreadID(Ident);
  Constant *NumVariables = Builder.getInt32(NumReductions);
  const DataLayout &DL = Module->getDataLayout();
  unsigned RedArrayByteSize = DL.getTypeStoreSize(RedArrayTy);
  Constant *RedArraySize = Builder.getInt64(RedArrayByteSize);
  Function *ReductionFunc = getFreshReductionFunc(*Module);
  Value *Lock = getOMPCriticalRegionLock(".reduction");
  Function *ReduceFunc = getOrCreateRuntimeFunctionPtr(
      IsNoWait ? RuntimeFunction::OMPRTL___kmpc_reduce_nowait
               : RuntimeFunction::OMPRTL___kmpc_reduce);
  CallInst *ReduceCall =
      Builder.CreateCall(ReduceFunc,
                         {Ident, ThreadId, NumVariables, RedArraySize,
                          RedArrayPtr, ReductionFunc, Lock},
                         "reduce");
 
  // Create final reduction entry blocks for the atomic and non-atomic case.
  // Emit IR that dispatches control flow to one of the blocks based on the
  // reduction supporting the atomic mode.
  BasicBlock *NonAtomicRedBlock =
      BasicBlock::Create(Module->getContext(), "reduce.switch.nonatomic", Func);
  BasicBlock *AtomicRedBlock =
      BasicBlock::Create(Module->getContext(), "reduce.switch.atomic", Func);
  SwitchInst *Switch =
      Builder.CreateSwitch(ReduceCall, ContinuationBlock, /* NumCases */ 2);
  Switch->addCase(Builder.getInt32(1), NonAtomicRedBlock);
  Switch->addCase(Builder.getInt32(2), AtomicRedBlock);
 
  // Populate the non-atomic reduction using the elementwise reduction function.
  // This loads the elements from the global and private variables and reduces
  // them before storing back the result to the global variable.
  Builder.SetInsertPoint(NonAtomicRedBlock);
  for (auto En : enumerate(ReductionInfos)) {
    const ReductionInfo &RI = En.value();
    Type *ValueType = RI.ElementType;
    Value *RedValue = Builder.CreateLoad(ValueType, RI.Variable,
                                         "red.value." + Twine(En.index()));
    Value *PrivateRedValue =
        Builder.CreateLoad(ValueType, RI.PrivateVariable,
                           "red.private.value." + Twine(En.index()));
    Value *Reduced;
    Builder.restoreIP(
        RI.ReductionGen(Builder.saveIP(), RedValue, PrivateRedValue, Reduced));
    if (!Builder.GetInsertBlock())
      return InsertPointTy();
    Builder.CreateStore(Reduced, RI.Variable);
  }
  Function *EndReduceFunc = getOrCreateRuntimeFunctionPtr(
      IsNoWait ? RuntimeFunction::OMPRTL___kmpc_end_reduce_nowait
               : RuntimeFunction::OMPRTL___kmpc_end_reduce);
  Builder.CreateCall(EndReduceFunc, {Ident, ThreadId, Lock});
  Builder.CreateBr(ContinuationBlock);
 
  // Populate the atomic reduction using the atomic elementwise reduction
  // function. There are no loads/stores here because they will be happening
  // inside the atomic elementwise reduction.
  Builder.SetInsertPoint(AtomicRedBlock);
  if (CanGenerateAtomic) {
    for (const ReductionInfo &RI : ReductionInfos) {
      Builder.restoreIP(RI.AtomicReductionGen(Builder.saveIP(), RI.ElementType,
                                              RI.Variable, RI.PrivateVariable));
      if (!Builder.GetInsertBlock())
        return InsertPointTy();
    }
    Builder.CreateBr(ContinuationBlock);
  } else {
    Builder.CreateUnreachable();
  }
 
  // Populate the outlined reduction function using the elementwise reduction
  // function. Partial values are extracted from the type-erased array of
  // pointers to private variables.
  BasicBlock *ReductionFuncBlock =
      BasicBlock::Create(Module->getContext(), "", ReductionFunc);
  Builder.SetInsertPoint(ReductionFuncBlock);
  Value *LHSArrayPtr = Builder.CreateBitCast(ReductionFunc->getArg(0),
                                             RedArrayTy->getPointerTo());
  Value *RHSArrayPtr = Builder.CreateBitCast(ReductionFunc->getArg(1),
                                             RedArrayTy->getPointerTo());
  for (auto En : enumerate(ReductionInfos)) {
    const ReductionInfo &RI = En.value();
    Value *LHSI8PtrPtr = Builder.CreateConstInBoundsGEP2_64(
        RedArrayTy, LHSArrayPtr, 0, En.index());
    Value *LHSI8Ptr = Builder.CreateLoad(Builder.getInt8PtrTy(), LHSI8PtrPtr);
    Value *LHSPtr = Builder.CreateBitCast(LHSI8Ptr, RI.Variable->getType());
    Value *LHS = Builder.CreateLoad(RI.ElementType, LHSPtr);
    Value *RHSI8PtrPtr = Builder.CreateConstInBoundsGEP2_64(
        RedArrayTy, RHSArrayPtr, 0, En.index());
    Value *RHSI8Ptr = Builder.CreateLoad(Builder.getInt8PtrTy(), RHSI8PtrPtr);
    Value *RHSPtr =
        Builder.CreateBitCast(RHSI8Ptr, RI.PrivateVariable->getType());
    Value *RHS = Builder.CreateLoad(RI.ElementType, RHSPtr);
    Value *Reduced;
    Builder.restoreIP(RI.ReductionGen(Builder.saveIP(), LHS, RHS, Reduced));
    if (!Builder.GetInsertBlock())
      return InsertPointTy();
    Builder.CreateStore(Reduced, LHSPtr);
  }
  Builder.CreateRetVoid();
 
  Builder.SetInsertPoint(ContinuationBlock);
  return Builder.saveIP();
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createMaster(const LocationDescription &Loc,
                              BodyGenCallbackTy BodyGenCB,
                              FinalizeCallbackTy FiniCB) {
 
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  Directive OMPD = Directive::OMPD_master;
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  Value *Args[] = {Ident, ThreadId};
 
  Function *EntryRTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_master);
  Instruction *EntryCall = Builder.CreateCall(EntryRTLFn, Args);
 
  Function *ExitRTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_end_master);
  Instruction *ExitCall = Builder.CreateCall(ExitRTLFn, Args);
 
  return EmitOMPInlinedRegion(OMPD, EntryCall, ExitCall, BodyGenCB, FiniCB,
                              /*Conditional*/ true, /*hasFinalize*/ true);
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createMasked(const LocationDescription &Loc,
                              BodyGenCallbackTy BodyGenCB,
                              FinalizeCallbackTy FiniCB, Value *Filter) {
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  Directive OMPD = Directive::OMPD_masked;
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  Value *Args[] = {Ident, ThreadId, Filter};
  Value *ArgsEnd[] = {Ident, ThreadId};
 
  Function *EntryRTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_masked);
  Instruction *EntryCall = Builder.CreateCall(EntryRTLFn, Args);
 
  Function *ExitRTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_end_masked);
  Instruction *ExitCall = Builder.CreateCall(ExitRTLFn, ArgsEnd);
 
  return EmitOMPInlinedRegion(OMPD, EntryCall, ExitCall, BodyGenCB, FiniCB,
                              /*Conditional*/ true, /*hasFinalize*/ true);
}
 
CanonicalLoopInfo *OpenMPIRBuilder::createLoopSkeleton(
    DebugLoc DL, Value *TripCount, Function *F, BasicBlock *PreInsertBefore,
    BasicBlock *PostInsertBefore, const Twine &Name) {
  Module *M = F->getParent();
  LLVMContext &Ctx = M->getContext();
  Type *IndVarTy = TripCount->getType();
 
  // Create the basic block structure.
  BasicBlock *Preheader =
      BasicBlock::Create(Ctx, "omp_" + Name + ".preheader", F, PreInsertBefore);
  BasicBlock *Header =
      BasicBlock::Create(Ctx, "omp_" + Name + ".header", F, PreInsertBefore);
  BasicBlock *Cond =
      BasicBlock::Create(Ctx, "omp_" + Name + ".cond", F, PreInsertBefore);
  BasicBlock *Body =
      BasicBlock::Create(Ctx, "omp_" + Name + ".body", F, PreInsertBefore);
  BasicBlock *Latch =
      BasicBlock::Create(Ctx, "omp_" + Name + ".inc", F, PostInsertBefore);
  BasicBlock *Exit =
      BasicBlock::Create(Ctx, "omp_" + Name + ".exit", F, PostInsertBefore);
  BasicBlock *After =
      BasicBlock::Create(Ctx, "omp_" + Name + ".after", F, PostInsertBefore);
 
  // Use specified DebugLoc for new instructions.
  Builder.SetCurrentDebugLocation(DL);
 
  Builder.SetInsertPoint(Preheader);
  Builder.CreateBr(Header);
 
  Builder.SetInsertPoint(Header);
  PHINode *IndVarPHI = Builder.CreatePHI(IndVarTy, 2, "omp_" + Name + ".iv");
  IndVarPHI->addIncoming(ConstantInt::get(IndVarTy, 0), Preheader);
  Builder.CreateBr(Cond);
 
  Builder.SetInsertPoint(Cond);
  Value *Cmp =
      Builder.CreateICmpULT(IndVarPHI, TripCount, "omp_" + Name + ".cmp");
  Builder.CreateCondBr(Cmp, Body, Exit);
 
  Builder.SetInsertPoint(Body);
  Builder.CreateBr(Latch);
 
  Builder.SetInsertPoint(Latch);
  Value *Next = Builder.CreateAdd(IndVarPHI, ConstantInt::get(IndVarTy, 1),
                                  "omp_" + Name + ".next", /*HasNUW=*/true);
  Builder.CreateBr(Header);
  IndVarPHI->addIncoming(Next, Latch);
 
  Builder.SetInsertPoint(Exit);
  Builder.CreateBr(After);
 
  // Remember and return the canonical control flow.
  LoopInfos.emplace_front();
  CanonicalLoopInfo *CL = &LoopInfos.front();
 
  CL->Header = Header;
  CL->Cond = Cond;
  CL->Latch = Latch;
  CL->Exit = Exit;
 
#ifndef NDEBUG
  CL->assertOK();
#endif
  return CL;
}
 
CanonicalLoopInfo *
OpenMPIRBuilder::createCanonicalLoop(const LocationDescription &Loc,
                                     LoopBodyGenCallbackTy BodyGenCB,
                                     Value *TripCount, const Twine &Name) {
  BasicBlock *BB = Loc.IP.getBlock();
  BasicBlock *NextBB = BB->getNextNode();
 
  CanonicalLoopInfo *CL = createLoopSkeleton(Loc.DL, TripCount, BB->getParent(),
                                             NextBB, NextBB, Name);
  BasicBlock *After = CL->getAfter();
 
  // If location is not set, don't connect the loop.
  if (updateToLocation(Loc)) {
    // Split the loop at the insertion point: Branch to the preheader and move
    // every following instruction to after the loop (the After BB). Also, the
    // new successor is the loop's after block.
    spliceBB(Builder, After, /*CreateBranch=*/false);
    Builder.CreateBr(CL->getPreheader());
  }
 
  // Emit the body content. We do it after connecting the loop to the CFG to
  // avoid that the callback encounters degenerate BBs.
  BodyGenCB(CL->getBodyIP(), CL->getIndVar());
 
#ifndef NDEBUG
  CL->assertOK();
#endif
  return CL;
}
 
CanonicalLoopInfo *OpenMPIRBuilder::createCanonicalLoop(
    const LocationDescription &Loc, LoopBodyGenCallbackTy BodyGenCB,
    Value *Start, Value *Stop, Value *Step, bool IsSigned, bool InclusiveStop,
    InsertPointTy ComputeIP, const Twine &Name) {
 
  // Consider the following difficulties (assuming 8-bit signed integers):
  //  * Adding \p Step to the loop counter which passes \p Stop may overflow:
  //      DO I = 1, 100, 50
  ///  * A \p Step of INT_MIN cannot not be normalized to a positive direction:
  //      DO I = 100, 0, -128
 
  // Start, Stop and Step must be of the same integer type.
  auto *IndVarTy = cast<IntegerType>(Start->getType());
  assert(IndVarTy == Stop->getType() && "Stop type mismatch");
  assert(IndVarTy == Step->getType() && "Step type mismatch");
 
  LocationDescription ComputeLoc =
      ComputeIP.isSet() ? LocationDescription(ComputeIP, Loc.DL) : Loc;
  updateToLocation(ComputeLoc);
 
  ConstantInt *Zero = ConstantInt::get(IndVarTy, 0);
  ConstantInt *One = ConstantInt::get(IndVarTy, 1);
 
  // Like Step, but always positive.
  Value *Incr = Step;
 
  // Distance between Start and Stop; always positive.
  Value *Span;
 
  // Condition whether there are no iterations are executed at all, e.g. because
  // UB < LB.
  Value *ZeroCmp;
 
  if (IsSigned) {
    // Ensure that increment is positive. If not, negate and invert LB and UB.
    Value *IsNeg = Builder.CreateICmpSLT(Step, Zero);
    Incr = Builder.CreateSelect(IsNeg, Builder.CreateNeg(Step), Step);
    Value *LB = Builder.CreateSelect(IsNeg, Stop, Start);
    Value *UB = Builder.CreateSelect(IsNeg, Start, Stop);
    Span = Builder.CreateSub(UB, LB, "", false, true);
    ZeroCmp = Builder.CreateICmp(
        InclusiveStop ? CmpInst::ICMP_SLT : CmpInst::ICMP_SLE, UB, LB);
  } else {
    Span = Builder.CreateSub(Stop, Start, "", true);
    ZeroCmp = Builder.CreateICmp(
        InclusiveStop ? CmpInst::ICMP_ULT : CmpInst::ICMP_ULE, Stop, Start);
  }
 
  Value *CountIfLooping;
  if (InclusiveStop) {
    CountIfLooping = Builder.CreateAdd(Builder.CreateUDiv(Span, Incr), One);
  } else {
    // Avoid incrementing past stop since it could overflow.
    Value *CountIfTwo = Builder.CreateAdd(
        Builder.CreateUDiv(Builder.CreateSub(Span, One), Incr), One);
    Value *OneCmp = Builder.CreateICmp(
        InclusiveStop ? CmpInst::ICMP_ULT : CmpInst::ICMP_ULE, Span, Incr);
    CountIfLooping = Builder.CreateSelect(OneCmp, One, CountIfTwo);
  }
  Value *TripCount = Builder.CreateSelect(ZeroCmp, Zero, CountIfLooping,
                                          "omp_" + Name + ".tripcount");
 
  auto BodyGen = [=](InsertPointTy CodeGenIP, Value *IV) {
    Builder.restoreIP(CodeGenIP);
    Value *Span = Builder.CreateMul(IV, Step);
    Value *IndVar = Builder.CreateAdd(Span, Start);
    BodyGenCB(Builder.saveIP(), IndVar);
  };
  LocationDescription LoopLoc = ComputeIP.isSet() ? Loc.IP : Builder.saveIP();
  return createCanonicalLoop(LoopLoc, BodyGen, TripCount, Name);
}
 
// Returns an LLVM function to call for initializing loop bounds using OpenMP
// static scheduling depending on `type`. Only i32 and i64 are supported by the
// runtime. Always interpret integers as unsigned similarly to
// CanonicalLoopInfo.
static FunctionCallee getKmpcForStaticInitForType(Type *Ty, Module &M,
                                                  OpenMPIRBuilder &OMPBuilder) {
  unsigned Bitwidth = Ty->getIntegerBitWidth();
  if (Bitwidth == 32)
    return OMPBuilder.getOrCreateRuntimeFunction(
        M, omp::RuntimeFunction::OMPRTL___kmpc_for_static_init_4u);
  if (Bitwidth == 64)
    return OMPBuilder.getOrCreateRuntimeFunction(
        M, omp::RuntimeFunction::OMPRTL___kmpc_for_static_init_8u);
  llvm_unreachable("unknown OpenMP loop iterator bitwidth");
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::applyStaticWorkshareLoop(DebugLoc DL, CanonicalLoopInfo *CLI,
                                          InsertPointTy AllocaIP,
                                          bool NeedsBarrier) {
  assert(CLI->isValid() && "Requires a valid canonical loop");
  assert(!isConflictIP(AllocaIP, CLI->getPreheaderIP()) &&
         "Require dedicated allocate IP");
 
  // Set up the source location value for OpenMP runtime.
  Builder.restoreIP(CLI->getPreheaderIP());
  Builder.SetCurrentDebugLocation(DL);
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(DL, SrcLocStrSize);
  Value *SrcLoc = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
 
  // Declare useful OpenMP runtime functions.
  Value *IV = CLI->getIndVar();
  Type *IVTy = IV->getType();
  FunctionCallee StaticInit = getKmpcForStaticInitForType(IVTy, M, *this);
  FunctionCallee StaticFini =
      getOrCreateRuntimeFunction(M, omp::OMPRTL___kmpc_for_static_fini);
 
  // Allocate space for computed loop bounds as expected by the "init" function.
  Builder.restoreIP(AllocaIP);
  Type *I32Type = Type::getInt32Ty(M.getContext());
  Value *PLastIter = Builder.CreateAlloca(I32Type, nullptr, "p.lastiter");
  Value *PLowerBound = Builder.CreateAlloca(IVTy, nullptr, "p.lowerbound");
  Value *PUpperBound = Builder.CreateAlloca(IVTy, nullptr, "p.upperbound");
  Value *PStride = Builder.CreateAlloca(IVTy, nullptr, "p.stride");
 
  // At the end of the preheader, prepare for calling the "init" function by
  // storing the current loop bounds into the allocated space. A canonical loop
  // always iterates from 0 to trip-count with step 1. Note that "init" expects
  // and produces an inclusive upper bound.
  Builder.SetInsertPoint(CLI->getPreheader()->getTerminator());
  Constant *Zero = ConstantInt::get(IVTy, 0);
  Constant *One = ConstantInt::get(IVTy, 1);
  Builder.CreateStore(Zero, PLowerBound);
  Value *UpperBound = Builder.CreateSub(CLI->getTripCount(), One);
  Builder.CreateStore(UpperBound, PUpperBound);
  Builder.CreateStore(One, PStride);
 
  Value *ThreadNum = getOrCreateThreadID(SrcLoc);
 
  Constant *SchedulingType = ConstantInt::get(
      I32Type, static_cast<int>(OMPScheduleType::UnorderedStatic));
 
  // Call the "init" function and update the trip count of the loop with the
  // value it produced.
  Builder.CreateCall(StaticInit,
                     {SrcLoc, ThreadNum, SchedulingType, PLastIter, PLowerBound,
                      PUpperBound, PStride, One, Zero});
  Value *LowerBound = Builder.CreateLoad(IVTy, PLowerBound);
  Value *InclusiveUpperBound = Builder.CreateLoad(IVTy, PUpperBound);
  Value *TripCountMinusOne = Builder.CreateSub(InclusiveUpperBound, LowerBound);
  Value *TripCount = Builder.CreateAdd(TripCountMinusOne, One);
  CLI->setTripCount(TripCount);
 
  // Update all uses of the induction variable except the one in the condition
  // block that compares it with the actual upper bound, and the increment in
  // the latch block.
 
  CLI->mapIndVar([&](Instruction *OldIV) -> Value * {
    Builder.SetInsertPoint(CLI->getBody(),
                           CLI->getBody()->getFirstInsertionPt());
    Builder.SetCurrentDebugLocation(DL);
    return Builder.CreateAdd(OldIV, LowerBound);
  });
 
  // In the "exit" block, call the "fini" function.
  Builder.SetInsertPoint(CLI->getExit(),
                         CLI->getExit()->getTerminator()->getIterator());
  Builder.CreateCall(StaticFini, {SrcLoc, ThreadNum});
 
  // Add the barrier if requested.
  if (NeedsBarrier)
    createBarrier(LocationDescription(Builder.saveIP(), DL),
                  omp::Directive::OMPD_for, /* ForceSimpleCall */ false,
                  /* CheckCancelFlag */ false);
 
  InsertPointTy AfterIP = CLI->getAfterIP();
  CLI->invalidate();
 
  return AfterIP;
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::applyStaticChunkedWorkshareLoop(
    DebugLoc DL, CanonicalLoopInfo *CLI, InsertPointTy AllocaIP,
    bool NeedsBarrier, Value *ChunkSize) {
  assert(CLI->isValid() && "Requires a valid canonical loop");
  assert(ChunkSize && "Chunk size is required");
 
  LLVMContext &Ctx = CLI->getFunction()->getContext();
  Value *IV = CLI->getIndVar();
  Value *OrigTripCount = CLI->getTripCount();
  Type *IVTy = IV->getType();
  assert(IVTy->getIntegerBitWidth() <= 64 &&
         "Max supported tripcount bitwidth is 64 bits");
  Type *InternalIVTy = IVTy->getIntegerBitWidth() <= 32 ? Type::getInt32Ty(Ctx)
                                                        : Type::getInt64Ty(Ctx);
  Type *I32Type = Type::getInt32Ty(M.getContext());
  Constant *Zero = ConstantInt::get(InternalIVTy, 0);
  Constant *One = ConstantInt::get(InternalIVTy, 1);
 
  // Declare useful OpenMP runtime functions.
  FunctionCallee StaticInit =
      getKmpcForStaticInitForType(InternalIVTy, M, *this);
  FunctionCallee StaticFini =
      getOrCreateRuntimeFunction(M, omp::OMPRTL___kmpc_for_static_fini);
 
  // Allocate space for computed loop bounds as expected by the "init" function.
  Builder.restoreIP(AllocaIP);
  Builder.SetCurrentDebugLocation(DL);
  Value *PLastIter = Builder.CreateAlloca(I32Type, nullptr, "p.lastiter");
  Value *PLowerBound =
      Builder.CreateAlloca(InternalIVTy, nullptr, "p.lowerbound");
  Value *PUpperBound =
      Builder.CreateAlloca(InternalIVTy, nullptr, "p.upperbound");
  Value *PStride = Builder.CreateAlloca(InternalIVTy, nullptr, "p.stride");
 
  // Set up the source location value for the OpenMP runtime.
  Builder.restoreIP(CLI->getPreheaderIP());
  Builder.SetCurrentDebugLocation(DL);
 
  // TODO: Detect overflow in ubsan or max-out with current tripcount.
  Value *CastedChunkSize =
      Builder.CreateZExtOrTrunc(ChunkSize, InternalIVTy, "chunksize");
  Value *CastedTripCount =
      Builder.CreateZExt(OrigTripCount, InternalIVTy, "tripcount");
 
  Constant *SchedulingType = ConstantInt::get(
      I32Type, static_cast<int>(OMPScheduleType::UnorderedStaticChunked));
  Builder.CreateStore(Zero, PLowerBound);
  Value *OrigUpperBound = Builder.CreateSub(CastedTripCount, One);
  Builder.CreateStore(OrigUpperBound, PUpperBound);
  Builder.CreateStore(One, PStride);
 
  // Call the "init" function and update the trip count of the loop with the
  // value it produced.
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(DL, SrcLocStrSize);
  Value *SrcLoc = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadNum = getOrCreateThreadID(SrcLoc);
  Builder.CreateCall(StaticInit,
                     {/*loc=*/SrcLoc, /*global_tid=*/ThreadNum,
                      /*schedtype=*/SchedulingType, /*plastiter=*/PLastIter,
                      /*plower=*/PLowerBound, /*pupper=*/PUpperBound,
                      /*pstride=*/PStride, /*incr=*/One,
                      /*chunk=*/CastedChunkSize});
 
  // Load values written by the "init" function.
  Value *FirstChunkStart =
      Builder.CreateLoad(InternalIVTy, PLowerBound, "omp_firstchunk.lb");
  Value *FirstChunkStop =
      Builder.CreateLoad(InternalIVTy, PUpperBound, "omp_firstchunk.ub");
  Value *FirstChunkEnd = Builder.CreateAdd(FirstChunkStop, One);
  Value *ChunkRange =
      Builder.CreateSub(FirstChunkEnd, FirstChunkStart, "omp_chunk.range");
  Value *NextChunkStride =
      Builder.CreateLoad(InternalIVTy, PStride, "omp_dispatch.stride");
 
  // Create outer "dispatch" loop for enumerating the chunks.
  BasicBlock *DispatchEnter = splitBB(Builder, true);
  Value *DispatchCounter;
  CanonicalLoopInfo *DispatchCLI = createCanonicalLoop(
      {Builder.saveIP(), DL},
      [&](InsertPointTy BodyIP, Value *Counter) { DispatchCounter = Counter; },
      FirstChunkStart, CastedTripCount, NextChunkStride,
      /*IsSigned=*/false, /*InclusiveStop=*/false, /*ComputeIP=*/{},
      "dispatch");
 
  // Remember the BasicBlocks of the dispatch loop we need, then invalidate to
  // not have to preserve the canonical invariant.
  BasicBlock *DispatchBody = DispatchCLI->getBody();
  BasicBlock *DispatchLatch = DispatchCLI->getLatch();
  BasicBlock *DispatchExit = DispatchCLI->getExit();
  BasicBlock *DispatchAfter = DispatchCLI->getAfter();
  DispatchCLI->invalidate();
 
  // Rewire the original loop to become the chunk loop inside the dispatch loop.
  redirectTo(DispatchAfter, CLI->getAfter(), DL);
  redirectTo(CLI->getExit(), DispatchLatch, DL);
  redirectTo(DispatchBody, DispatchEnter, DL);
 
  // Prepare the prolog of the chunk loop.
  Builder.restoreIP(CLI->getPreheaderIP());
  Builder.SetCurrentDebugLocation(DL);
 
  // Compute the number of iterations of the chunk loop.
  Builder.SetInsertPoint(CLI->getPreheader()->getTerminator());
  Value *ChunkEnd = Builder.CreateAdd(DispatchCounter, ChunkRange);
  Value *IsLastChunk =
      Builder.CreateICmpUGE(ChunkEnd, CastedTripCount, "omp_chunk.is_last");
  Value *CountUntilOrigTripCount =
      Builder.CreateSub(CastedTripCount, DispatchCounter);
  Value *ChunkTripCount = Builder.CreateSelect(
      IsLastChunk, CountUntilOrigTripCount, ChunkRange, "omp_chunk.tripcount");
  Value *BackcastedChunkTC =
      Builder.CreateTrunc(ChunkTripCount, IVTy, "omp_chunk.tripcount.trunc");
  CLI->setTripCount(BackcastedChunkTC);
 
  // Update all uses of the induction variable except the one in the condition
  // block that compares it with the actual upper bound, and the increment in
  // the latch block.
  Value *BackcastedDispatchCounter =
      Builder.CreateTrunc(DispatchCounter, IVTy, "omp_dispatch.iv.trunc");
  CLI->mapIndVar([&](Instruction *) -> Value * {
    Builder.restoreIP(CLI->getBodyIP());
    return Builder.CreateAdd(IV, BackcastedDispatchCounter);
  });
 
  // In the "exit" block, call the "fini" function.
  Builder.SetInsertPoint(DispatchExit, DispatchExit->getFirstInsertionPt());
  Builder.CreateCall(StaticFini, {SrcLoc, ThreadNum});
 
  // Add the barrier if requested.
  if (NeedsBarrier)
    createBarrier(LocationDescription(Builder.saveIP(), DL), OMPD_for,
                  /*ForceSimpleCall=*/false, /*CheckCancelFlag=*/false);
 
#ifndef NDEBUG
  // Even though we currently do not support applying additional methods to it,
  // the chunk loop should remain a canonical loop.
  CLI->assertOK();
#endif
 
  return {DispatchAfter, DispatchAfter->getFirstInsertionPt()};
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::applyWorkshareLoop(
    DebugLoc DL, CanonicalLoopInfo *CLI, InsertPointTy AllocaIP,
    bool NeedsBarrier, llvm::omp::ScheduleKind SchedKind,
    llvm::Value *ChunkSize, bool HasSimdModifier, bool HasMonotonicModifier,
    bool HasNonmonotonicModifier, bool HasOrderedClause) {
  OMPScheduleType EffectiveScheduleType = computeOpenMPScheduleType(
      SchedKind, ChunkSize, HasSimdModifier, HasMonotonicModifier,
      HasNonmonotonicModifier, HasOrderedClause);
 
  bool IsOrdered = (EffectiveScheduleType & OMPScheduleType::ModifierOrdered) ==
                   OMPScheduleType::ModifierOrdered;
  switch (EffectiveScheduleType & ~OMPScheduleType::ModifierMask) {
  case OMPScheduleType::BaseStatic:
    assert(!ChunkSize && "No chunk size with static-chunked schedule");
    if (IsOrdered)
      return applyDynamicWorkshareLoop(DL, CLI, AllocaIP, EffectiveScheduleType,
                                       NeedsBarrier, ChunkSize);
    // FIXME: Monotonicity ignored?
    return applyStaticWorkshareLoop(DL, CLI, AllocaIP, NeedsBarrier);
 
  case OMPScheduleType::BaseStaticChunked:
    if (IsOrdered)
      return applyDynamicWorkshareLoop(DL, CLI, AllocaIP, EffectiveScheduleType,
                                       NeedsBarrier, ChunkSize);
    // FIXME: Monotonicity ignored?
    return applyStaticChunkedWorkshareLoop(DL, CLI, AllocaIP, NeedsBarrier,
                                           ChunkSize);
 
  case OMPScheduleType::BaseRuntime:
  case OMPScheduleType::BaseAuto:
  case OMPScheduleType::BaseGreedy:
  case OMPScheduleType::BaseBalanced:
  case OMPScheduleType::BaseSteal:
  case OMPScheduleType::BaseGuidedSimd:
  case OMPScheduleType::BaseRuntimeSimd:
    assert(!ChunkSize &&
           "schedule type does not support user-defined chunk sizes");
    LLVM_FALLTHROUGH;
  case OMPScheduleType::BaseDynamicChunked:
  case OMPScheduleType::BaseGuidedChunked:
  case OMPScheduleType::BaseGuidedIterativeChunked:
  case OMPScheduleType::BaseGuidedAnalyticalChunked:
  case OMPScheduleType::BaseStaticBalancedChunked:
    return applyDynamicWorkshareLoop(DL, CLI, AllocaIP, EffectiveScheduleType,
                                     NeedsBarrier, ChunkSize);
 
  default:
    llvm_unreachable("Unknown/unimplemented schedule kind");
  }
}
 
/// Returns an LLVM function to call for initializing loop bounds using OpenMP
/// dynamic scheduling depending on `type`. Only i32 and i64 are supported by
/// the runtime. Always interpret integers as unsigned similarly to
/// CanonicalLoopInfo.
static FunctionCallee
getKmpcForDynamicInitForType(Type *Ty, Module &M, OpenMPIRBuilder &OMPBuilder) {
  unsigned Bitwidth = Ty->getIntegerBitWidth();
  if (Bitwidth == 32)
    return OMPBuilder.getOrCreateRuntimeFunction(
        M, omp::RuntimeFunction::OMPRTL___kmpc_dispatch_init_4u);
  if (Bitwidth == 64)
    return OMPBuilder.getOrCreateRuntimeFunction(
        M, omp::RuntimeFunction::OMPRTL___kmpc_dispatch_init_8u);
  llvm_unreachable("unknown OpenMP loop iterator bitwidth");
}
 
/// Returns an LLVM function to call for updating the next loop using OpenMP
/// dynamic scheduling depending on `type`. Only i32 and i64 are supported by
/// the runtime. Always interpret integers as unsigned similarly to
/// CanonicalLoopInfo.
static FunctionCallee
getKmpcForDynamicNextForType(Type *Ty, Module &M, OpenMPIRBuilder &OMPBuilder) {
  unsigned Bitwidth = Ty->getIntegerBitWidth();
  if (Bitwidth == 32)
    return OMPBuilder.getOrCreateRuntimeFunction(
        M, omp::RuntimeFunction::OMPRTL___kmpc_dispatch_next_4u);
  if (Bitwidth == 64)
    return OMPBuilder.getOrCreateRuntimeFunction(
        M, omp::RuntimeFunction::OMPRTL___kmpc_dispatch_next_8u);
  llvm_unreachable("unknown OpenMP loop iterator bitwidth");
}
 
/// Returns an LLVM function to call for finalizing the dynamic loop using
/// depending on `type`. Only i32 and i64 are supported by the runtime. Always
/// interpret integers as unsigned similarly to CanonicalLoopInfo.
static FunctionCallee
getKmpcForDynamicFiniForType(Type *Ty, Module &M, OpenMPIRBuilder &OMPBuilder) {
  unsigned Bitwidth = Ty->getIntegerBitWidth();
  if (Bitwidth == 32)
    return OMPBuilder.getOrCreateRuntimeFunction(
        M, omp::RuntimeFunction::OMPRTL___kmpc_dispatch_fini_4u);
  if (Bitwidth == 64)
    return OMPBuilder.getOrCreateRuntimeFunction(
        M, omp::RuntimeFunction::OMPRTL___kmpc_dispatch_fini_8u);
  llvm_unreachable("unknown OpenMP loop iterator bitwidth");
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::applyDynamicWorkshareLoop(
    DebugLoc DL, CanonicalLoopInfo *CLI, InsertPointTy AllocaIP,
    OMPScheduleType SchedType, bool NeedsBarrier, Value *Chunk) {
  assert(CLI->isValid() && "Requires a valid canonical loop");
  assert(!isConflictIP(AllocaIP, CLI->getPreheaderIP()) &&
         "Require dedicated allocate IP");
  assert(isValidWorkshareLoopScheduleType(SchedType) &&
         "Require valid schedule type");
 
  bool Ordered = (SchedType & OMPScheduleType::ModifierOrdered) ==
                 OMPScheduleType::ModifierOrdered;
 
  // Set up the source location value for OpenMP runtime.
  Builder.SetCurrentDebugLocation(DL);
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(DL, SrcLocStrSize);
  Value *SrcLoc = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
 
  // Declare useful OpenMP runtime functions.
  Value *IV = CLI->getIndVar();
  Type *IVTy = IV->getType();
  FunctionCallee DynamicInit = getKmpcForDynamicInitForType(IVTy, M, *this);
  FunctionCallee DynamicNext = getKmpcForDynamicNextForType(IVTy, M, *this);
 
  // Allocate space for computed loop bounds as expected by the "init" function.
  Builder.restoreIP(AllocaIP);
  Type *I32Type = Type::getInt32Ty(M.getContext());
  Value *PLastIter = Builder.CreateAlloca(I32Type, nullptr, "p.lastiter");
  Value *PLowerBound = Builder.CreateAlloca(IVTy, nullptr, "p.lowerbound");
  Value *PUpperBound = Builder.CreateAlloca(IVTy, nullptr, "p.upperbound");
  Value *PStride = Builder.CreateAlloca(IVTy, nullptr, "p.stride");
 
  // At the end of the preheader, prepare for calling the "init" function by
  // storing the current loop bounds into the allocated space. A canonical loop
  // always iterates from 0 to trip-count with step 1. Note that "init" expects
  // and produces an inclusive upper bound.
  BasicBlock *PreHeader = CLI->getPreheader();
  Builder.SetInsertPoint(PreHeader->getTerminator());
  Constant *One = ConstantInt::get(IVTy, 1);
  Builder.CreateStore(One, PLowerBound);
  Value *UpperBound = CLI->getTripCount();
  Builder.CreateStore(UpperBound, PUpperBound);
  Builder.CreateStore(One, PStride);
 
  BasicBlock *Header = CLI->getHeader();
  BasicBlock *Exit = CLI->getExit();
  BasicBlock *Cond = CLI->getCond();
  BasicBlock *Latch = CLI->getLatch();
  InsertPointTy AfterIP = CLI->getAfterIP();
 
  // The CLI will be "broken" in the code below, as the loop is no longer
  // a valid canonical loop.
 
  if (!Chunk)
    Chunk = One;
 
  Value *ThreadNum = getOrCreateThreadID(SrcLoc);
 
  Constant *SchedulingType =
      ConstantInt::get(I32Type, static_cast<int>(SchedType));
 
  // Call the "init" function.
  Builder.CreateCall(DynamicInit,
                     {SrcLoc, ThreadNum, SchedulingType, /* LowerBound */ One,
                      UpperBound, /* step */ One, Chunk});
 
  // An outer loop around the existing one.
  BasicBlock *OuterCond = BasicBlock::Create(
      PreHeader->getContext(), Twine(PreHeader->getName()) + ".outer.cond",
      PreHeader->getParent());
  // This needs to be 32-bit always, so can't use the IVTy Zero above.
  Builder.SetInsertPoint(OuterCond, OuterCond->getFirstInsertionPt());
  Value *Res =
      Builder.CreateCall(DynamicNext, {SrcLoc, ThreadNum, PLastIter,
                                       PLowerBound, PUpperBound, PStride});
  Constant *Zero32 = ConstantInt::get(I32Type, 0);
  Value *MoreWork = Builder.CreateCmp(CmpInst::ICMP_NE, Res, Zero32);
  Value *LowerBound =
      Builder.CreateSub(Builder.CreateLoad(IVTy, PLowerBound), One, "lb");
  Builder.CreateCondBr(MoreWork, Header, Exit);
 
  // Change PHI-node in loop header to use outer cond rather than preheader,
  // and set IV to the LowerBound.
  Instruction *Phi = &Header->front();
  auto *PI = cast<PHINode>(Phi);
  PI->setIncomingBlock(0, OuterCond);
  PI->setIncomingValue(0, LowerBound);
 
  // Then set the pre-header to jump to the OuterCond
  Instruction *Term = PreHeader->getTerminator();
  auto *Br = cast<BranchInst>(Term);
  Br->setSuccessor(0, OuterCond);
 
  // Modify the inner condition:
  // * Use the UpperBound returned from the DynamicNext call.
  // * jump to the loop outer loop when done with one of the inner loops.
  Builder.SetInsertPoint(Cond, Cond->getFirstInsertionPt());
  UpperBound = Builder.CreateLoad(IVTy, PUpperBound, "ub");
  Instruction *Comp = &*Builder.GetInsertPoint();
  auto *CI = cast<CmpInst>(Comp);
  CI->setOperand(1, UpperBound);
  // Redirect the inner exit to branch to outer condition.
  Instruction *Branch = &Cond->back();
  auto *BI = cast<BranchInst>(Branch);
  assert(BI->getSuccessor(1) == Exit);
  BI->setSuccessor(1, OuterCond);
 
  // Call the "fini" function if "ordered" is present in wsloop directive.
  if (Ordered) {
    Builder.SetInsertPoint(&Latch->back());
    FunctionCallee DynamicFini = getKmpcForDynamicFiniForType(IVTy, M, *this);
    Builder.CreateCall(DynamicFini, {SrcLoc, ThreadNum});
  }
 
  // Add the barrier if requested.
  if (NeedsBarrier) {
    Builder.SetInsertPoint(&Exit->back());
    createBarrier(LocationDescription(Builder.saveIP(), DL),
                  omp::Directive::OMPD_for, /* ForceSimpleCall */ false,
                  /* CheckCancelFlag */ false);
  }
 
  CLI->invalidate();
  return AfterIP;
}
 
/// Redirect all edges that branch to \p OldTarget to \p NewTarget. That is,
/// after this \p OldTarget will be orphaned.
static void redirectAllPredecessorsTo(BasicBlock *OldTarget,
                                      BasicBlock *NewTarget, DebugLoc DL) {
  for (BasicBlock *Pred : make_early_inc_range(predecessors(OldTarget)))
    redirectTo(Pred, NewTarget, DL);
}
 
/// Determine which blocks in \p BBs are reachable from outside and remove the
/// ones that are not reachable from the function.
static void removeUnusedBlocksFromParent(ArrayRef<BasicBlock *> BBs) {
  SmallPtrSet<BasicBlock *, 6> BBsToErase{BBs.begin(), BBs.end()};
  auto HasRemainingUses = [&BBsToErase](BasicBlock *BB) {
    for (Use &U : BB->uses()) {
      auto *UseInst = dyn_cast<Instruction>(U.getUser());
      if (!UseInst)
        continue;
      if (BBsToErase.count(UseInst->getParent()))
        continue;
      return true;
    }
    return false;
  };
 
  while (true) {
    bool Changed = false;
    for (BasicBlock *BB : make_early_inc_range(BBsToErase)) {
      if (HasRemainingUses(BB)) {
        BBsToErase.erase(BB);
        Changed = true;
      }
    }
    if (!Changed)
      break;
  }
 
  SmallVector<BasicBlock *, 7> BBVec(BBsToErase.begin(), BBsToErase.end());
  DeleteDeadBlocks(BBVec);
}
 
CanonicalLoopInfo *
OpenMPIRBuilder::collapseLoops(DebugLoc DL, ArrayRef<CanonicalLoopInfo *> Loops,
                               InsertPointTy ComputeIP) {
  assert(Loops.size() >= 1 && "At least one loop required");
  size_t NumLoops = Loops.size();
 
  // Nothing to do if there is already just one loop.
  if (NumLoops == 1)
    return Loops.front();
 
  CanonicalLoopInfo *Outermost = Loops.front();
  CanonicalLoopInfo *Innermost = Loops.back();
  BasicBlock *OrigPreheader = Outermost->getPreheader();
  BasicBlock *OrigAfter = Outermost->getAfter();
  Function *F = OrigPreheader->getParent();
 
  // Loop control blocks that may become orphaned later.
  SmallVector<BasicBlock *, 12> OldControlBBs;
  OldControlBBs.reserve(6 * Loops.size());
  for (CanonicalLoopInfo *Loop : Loops)
    Loop->collectControlBlocks(OldControlBBs);
 
  // Setup the IRBuilder for inserting the trip count computation.
  Builder.SetCurrentDebugLocation(DL);
  if (ComputeIP.isSet())
    Builder.restoreIP(ComputeIP);
  else
    Builder.restoreIP(Outermost->getPreheaderIP());
 
  // Derive the collapsed' loop trip count.
  // TODO: Find common/largest indvar type.
  Value *CollapsedTripCount = nullptr;
  for (CanonicalLoopInfo *L : Loops) {
    assert(L->isValid() &&
           "All loops to collapse must be valid canonical loops");
    Value *OrigTripCount = L->getTripCount();
    if (!CollapsedTripCount) {
      CollapsedTripCount = OrigTripCount;
      continue;
    }
 
    // TODO: Enable UndefinedSanitizer to diagnose an overflow here.
    CollapsedTripCount = Builder.CreateMul(CollapsedTripCount, OrigTripCount,
                                           {}, /*HasNUW=*/true);
  }
 
  // Create the collapsed loop control flow.
  CanonicalLoopInfo *Result =
      createLoopSkeleton(DL, CollapsedTripCount, F,
                         OrigPreheader->getNextNode(), OrigAfter, "collapsed");
 
  // Build the collapsed loop body code.
  // Start with deriving the input loop induction variables from the collapsed
  // one, using a divmod scheme. To preserve the original loops' order, the
  // innermost loop use the least significant bits.
  Builder.restoreIP(Result->getBodyIP());
 
  Value *Leftover = Result->getIndVar();
  SmallVector<Value *> NewIndVars;
  NewIndVars.resize(NumLoops);
  for (int i = NumLoops - 1; i >= 1; --i) {
    Value *OrigTripCount = Loops[i]->getTripCount();
 
    Value *NewIndVar = Builder.CreateURem(Leftover, OrigTripCount);
    NewIndVars[i] = NewIndVar;
 
    Leftover = Builder.CreateUDiv(Leftover, OrigTripCount);
  }
  // Outermost loop gets all the remaining bits.
  NewIndVars[0] = Leftover;
 
  // Construct the loop body control flow.
  // We progressively construct the branch structure following in direction of
  // the control flow, from the leading in-between code, the loop nest body, the
  // trailing in-between code, and rejoining the collapsed loop's latch.
  // ContinueBlock and ContinuePred keep track of the source(s) of next edge. If
  // the ContinueBlock is set, continue with that block. If ContinuePred, use
  // its predecessors as sources.
  BasicBlock *ContinueBlock = Result->getBody();
  BasicBlock *ContinuePred = nullptr;
  auto ContinueWith = [&ContinueBlock, &ContinuePred, DL](BasicBlock *Dest,
                                                          BasicBlock *NextSrc) {
    if (ContinueBlock)
      redirectTo(ContinueBlock, Dest, DL);
    else
      redirectAllPredecessorsTo(ContinuePred, Dest, DL);
 
    ContinueBlock = nullptr;
    ContinuePred = NextSrc;
  };
 
  // The code before the nested loop of each level.
  // Because we are sinking it into the nest, it will be executed more often
  // that the original loop. More sophisticated schemes could keep track of what
  // the in-between code is and instantiate it only once per thread.
  for (size_t i = 0; i < NumLoops - 1; ++i)
    ContinueWith(Loops[i]->getBody(), Loops[i + 1]->getHeader());
 
  // Connect the loop nest body.
  ContinueWith(Innermost->getBody(), Innermost->getLatch());
 
  // The code after the nested loop at each level.
  for (size_t i = NumLoops - 1; i > 0; --i)
    ContinueWith(Loops[i]->getAfter(), Loops[i - 1]->getLatch());
 
  // Connect the finished loop to the collapsed loop latch.
  ContinueWith(Result->getLatch(), nullptr);
 
  // Replace the input loops with the new collapsed loop.
  redirectTo(Outermost->getPreheader(), Result->getPreheader(), DL);
  redirectTo(Result->getAfter(), Outermost->getAfter(), DL);
 
  // Replace the input loop indvars with the derived ones.
  for (size_t i = 0; i < NumLoops; ++i)
    Loops[i]->getIndVar()->replaceAllUsesWith(NewIndVars[i]);
 
  // Remove unused parts of the input loops.
  removeUnusedBlocksFromParent(OldControlBBs);
 
  for (CanonicalLoopInfo *L : Loops)
    L->invalidate();
 
#ifndef NDEBUG
  Result->assertOK();
#endif
  return Result;
}
 
std::vector<CanonicalLoopInfo *>
OpenMPIRBuilder::tileLoops(DebugLoc DL, ArrayRef<CanonicalLoopInfo *> Loops,
                           ArrayRef<Value *> TileSizes) {
  assert(TileSizes.size() == Loops.size() &&
         "Must pass as many tile sizes as there are loops");
  int NumLoops = Loops.size();
  assert(NumLoops >= 1 && "At least one loop to tile required");
 
  CanonicalLoopInfo *OutermostLoop = Loops.front();
  CanonicalLoopInfo *InnermostLoop = Loops.back();
  Function *F = OutermostLoop->getBody()->getParent();
  BasicBlock *InnerEnter = InnermostLoop->getBody();
  BasicBlock *InnerLatch = InnermostLoop->getLatch();
 
  // Loop control blocks that may become orphaned later.
  SmallVector<BasicBlock *, 12> OldControlBBs;
  OldControlBBs.reserve(6 * Loops.size());
  for (CanonicalLoopInfo *Loop : Loops)
    Loop->collectControlBlocks(OldControlBBs);
 
  // Collect original trip counts and induction variable to be accessible by
  // index. Also, the structure of the original loops is not preserved during
  // the construction of the tiled loops, so do it before we scavenge the BBs of
  // any original CanonicalLoopInfo.
  SmallVector<Value *, 4> OrigTripCounts, OrigIndVars;
  for (CanonicalLoopInfo *L : Loops) {
    assert(L->isValid() && "All input loops must be valid canonical loops");
    OrigTripCounts.push_back(L->getTripCount());
    OrigIndVars.push_back(L->getIndVar());
  }
 
  // Collect the code between loop headers. These may contain SSA definitions
  // that are used in the loop nest body. To be usable with in the innermost
  // body, these BasicBlocks will be sunk into the loop nest body. That is,
  // these instructions may be executed more often than before the tiling.
  // TODO: It would be sufficient to only sink them into body of the
  // corresponding tile loop.
  SmallVector<std::pair<BasicBlock *, BasicBlock *>, 4> InbetweenCode;
  for (int i = 0; i < NumLoops - 1; ++i) {
    CanonicalLoopInfo *Surrounding = Loops[i];
    CanonicalLoopInfo *Nested = Loops[i + 1];
 
    BasicBlock *EnterBB = Surrounding->getBody();
    BasicBlock *ExitBB = Nested->getHeader();
    InbetweenCode.emplace_back(EnterBB, ExitBB);
  }
 
  // Compute the trip counts of the floor loops.
  Builder.SetCurrentDebugLocation(DL);
  Builder.restoreIP(OutermostLoop->getPreheaderIP());
  SmallVector<Value *, 4> FloorCount, FloorRems;
  for (int i = 0; i < NumLoops; ++i) {
    Value *TileSize = TileSizes[i];
    Value *OrigTripCount = OrigTripCounts[i];
    Type *IVType = OrigTripCount->getType();
 
    Value *FloorTripCount = Builder.CreateUDiv(OrigTripCount, TileSize);
    Value *FloorTripRem = Builder.CreateURem(OrigTripCount, TileSize);
 
    // 0 if tripcount divides the tilesize, 1 otherwise.
    // 1 means we need an additional iteration for a partial tile.
    //
    // Unfortunately we cannot just use the roundup-formula
    //   (tripcount + tilesize - 1)/tilesize
    // because the summation might overflow. We do not want introduce undefined
    // behavior when the untiled loop nest did not.
    Value *FloorTripOverflow =
        Builder.CreateICmpNE(FloorTripRem, ConstantInt::get(IVType, 0));
 
    FloorTripOverflow = Builder.CreateZExt(FloorTripOverflow, IVType);
    FloorTripCount =
        Builder.CreateAdd(FloorTripCount, FloorTripOverflow,
                          "omp_floor" + Twine(i) + ".tripcount", true);
 
    // Remember some values for later use.
    FloorCount.push_back(FloorTripCount);
    FloorRems.push_back(FloorTripRem);
  }
 
  // Generate the new loop nest, from the outermost to the innermost.
  std::vector<CanonicalLoopInfo *> Result;
  Result.reserve(NumLoops * 2);
 
  // The basic block of the surrounding loop that enters the nest generated
  // loop.
  BasicBlock *Enter = OutermostLoop->getPreheader();
 
  // The basic block of the surrounding loop where the inner code should
  // continue.
  BasicBlock *Continue = OutermostLoop->getAfter();
 
  // Where the next loop basic block should be inserted.
  BasicBlock *OutroInsertBefore = InnermostLoop->getExit();
 
  auto EmbeddNewLoop =
      [this, DL, F, InnerEnter, &Enter, &Continue, &OutroInsertBefore](
          Value *TripCount, const Twine &Name) -> CanonicalLoopInfo * {
    CanonicalLoopInfo *EmbeddedLoop = createLoopSkeleton(
        DL, TripCount, F, InnerEnter, OutroInsertBefore, Name);
    redirectTo(Enter, EmbeddedLoop->getPreheader(), DL);
    redirectTo(EmbeddedLoop->getAfter(), Continue, DL);
 
    // Setup the position where the next embedded loop connects to this loop.
    Enter = EmbeddedLoop->getBody();
    Continue = EmbeddedLoop->getLatch();
    OutroInsertBefore = EmbeddedLoop->getLatch();
    return EmbeddedLoop;
  };
 
  auto EmbeddNewLoops = [&Result, &EmbeddNewLoop](ArrayRef<Value *> TripCounts,
                                                  const Twine &NameBase) {
    for (auto P : enumerate(TripCounts)) {
      CanonicalLoopInfo *EmbeddedLoop =
          EmbeddNewLoop(P.value(), NameBase + Twine(P.index()));
      Result.push_back(EmbeddedLoop);
    }
  };
 
  EmbeddNewLoops(FloorCount, "floor");
 
  // Within the innermost floor loop, emit the code that computes the tile
  // sizes.
  Builder.SetInsertPoint(Enter->getTerminator());
  SmallVector<Value *, 4> TileCounts;
  for (int i = 0; i < NumLoops; ++i) {
    CanonicalLoopInfo *FloorLoop = Result[i];
    Value *TileSize = TileSizes[i];
 
    Value *FloorIsEpilogue =
        Builder.CreateICmpEQ(FloorLoop->getIndVar(), FloorCount[i]);
    Value *TileTripCount =
        Builder.CreateSelect(FloorIsEpilogue, FloorRems[i], TileSize);
 
    TileCounts.push_back(TileTripCount);
  }
 
  // Create the tile loops.
  EmbeddNewLoops(TileCounts, "tile");
 
  // Insert the inbetween code into the body.
  BasicBlock *BodyEnter = Enter;
  BasicBlock *BodyEntered = nullptr;
  for (std::pair<BasicBlock *, BasicBlock *> P : InbetweenCode) {
    BasicBlock *EnterBB = P.first;
    BasicBlock *ExitBB = P.second;
 
    if (BodyEnter)
      redirectTo(BodyEnter, EnterBB, DL);
    else
      redirectAllPredecessorsTo(BodyEntered, EnterBB, DL);
 
    BodyEnter = nullptr;
    BodyEntered = ExitBB;
  }
 
  // Append the original loop nest body into the generated loop nest body.
  if (BodyEnter)
    redirectTo(BodyEnter, InnerEnter, DL);
  else
    redirectAllPredecessorsTo(BodyEntered, InnerEnter, DL);
  redirectAllPredecessorsTo(InnerLatch, Continue, DL);
 
  // Replace the original induction variable with an induction variable computed
  // from the tile and floor induction variables.
  Builder.restoreIP(Result.back()->getBodyIP());
  for (int i = 0; i < NumLoops; ++i) {
    CanonicalLoopInfo *FloorLoop = Result[i];
    CanonicalLoopInfo *TileLoop = Result[NumLoops + i];
    Value *OrigIndVar = OrigIndVars[i];
    Value *Size = TileSizes[i];
 
    Value *Scale =
        Builder.CreateMul(Size, FloorLoop->getIndVar(), {}, /*HasNUW=*/true);
    Value *Shift =
        Builder.CreateAdd(Scale, TileLoop->getIndVar(), {}, /*HasNUW=*/true);
    OrigIndVar->replaceAllUsesWith(Shift);
  }
 
  // Remove unused parts of the original loops.
  removeUnusedBlocksFromParent(OldControlBBs);
 
  for (CanonicalLoopInfo *L : Loops)
    L->invalidate();
 
#ifndef NDEBUG
  for (CanonicalLoopInfo *GenL : Result)
    GenL->assertOK();
#endif
  return Result;
}
 
/// Attach metadata \p Properties to the basic block described by \p BB. If the
/// basic block already has metadata, the basic block properties are appended.
static void addBasicBlockMetadata(BasicBlock *BB,
                                  ArrayRef<Metadata *> Properties) {
  // Nothing to do if no property to attach.
  if (Properties.empty())
    return;
 
  LLVMContext &Ctx = BB->getContext();
  SmallVector<Metadata *> NewProperties;
  NewProperties.push_back(nullptr);
 
  // If the basic block already has metadata, prepend it to the new metadata.
  MDNode *Existing = BB->getTerminator()->getMetadata(LLVMContext::MD_loop);
  if (Existing)
    append_range(NewProperties, drop_begin(Existing->operands(), 1));
 
  append_range(NewProperties, Properties);
  MDNode *BasicBlockID = MDNode::getDistinct(Ctx, NewProperties);
  BasicBlockID->replaceOperandWith(0, BasicBlockID);
 
  BB->getTerminator()->setMetadata(LLVMContext::MD_loop, BasicBlockID);
}
 
/// Attach loop metadata \p Properties to the loop described by \p Loop. If the
/// loop already has metadata, the loop properties are appended.
static void addLoopMetadata(CanonicalLoopInfo *Loop,
                            ArrayRef<Metadata *> Properties) {
  assert(Loop->isValid() && "Expecting a valid CanonicalLoopInfo");
 
  // Attach metadata to the loop's latch
  BasicBlock *Latch = Loop->getLatch();
  assert(Latch && "A valid CanonicalLoopInfo must have a unique latch");
  addBasicBlockMetadata(Latch, Properties);
}
 
/// Attach llvm.access.group metadata to the memref instructions of \p Block
static void addSimdMetadata(BasicBlock *Block, MDNode *AccessGroup,
                            LoopInfo &LI) {
  for (Instruction &I : *Block) {
    if (I.mayReadOrWriteMemory()) {
      // TODO: This instruction may already have access group from
      // other pragmas e.g. #pragma clang loop vectorize.  Append
      // so that the existing metadata is not overwritten.
      I.setMetadata(LLVMContext::MD_access_group, AccessGroup);
    }
  }
}
 
void OpenMPIRBuilder::unrollLoopFull(DebugLoc, CanonicalLoopInfo *Loop) {
  LLVMContext &Ctx = Builder.getContext();
  addLoopMetadata(
      Loop, {MDNode::get(Ctx, MDString::get(Ctx, "llvm.loop.unroll.enable")),
             MDNode::get(Ctx, MDString::get(Ctx, "llvm.loop.unroll.full"))});
}
 
void OpenMPIRBuilder::unrollLoopHeuristic(DebugLoc, CanonicalLoopInfo *Loop) {
  LLVMContext &Ctx = Builder.getContext();
  addLoopMetadata(
      Loop, {
                MDNode::get(Ctx, MDString::get(Ctx, "llvm.loop.unroll.enable")),
            });
}
 
void OpenMPIRBuilder::createIfVersion(CanonicalLoopInfo *CanonicalLoop,
                                      Value *IfCond, ValueToValueMapTy &VMap,
                                      const Twine &NamePrefix) {
  Function *F = CanonicalLoop->getFunction();
 
  // Define where if branch should be inserted
  Instruction *SplitBefore;
  if (Instruction::classof(IfCond)) {
    SplitBefore = dyn_cast<Instruction>(IfCond);
  } else {
    SplitBefore = CanonicalLoop->getPreheader()->getTerminator();
  }
 
  // TODO: We should not rely on pass manager. Currently we use pass manager
  // only for getting llvm::Loop which corresponds to given CanonicalLoopInfo
  // object. We should have a method  which returns all blocks between
  // CanonicalLoopInfo::getHeader() and CanonicalLoopInfo::getAfter()
  FunctionAnalysisManager FAM;
  FAM.registerPass([]() { return DominatorTreeAnalysis(); });
  FAM.registerPass([]() { return LoopAnalysis(); });
  FAM.registerPass([]() { return PassInstrumentationAnalysis(); });
 
  // Get the loop which needs to be cloned
  LoopAnalysis LIA;
  LoopInfo &&LI = LIA.run(*F, FAM);
  Loop *L = LI.getLoopFor(CanonicalLoop->getHeader());
 
  // Create additional blocks for the if statement
  BasicBlock *Head = SplitBefore->getParent();
  Instruction *HeadOldTerm = Head->getTerminator();
  llvm::LLVMContext &C = Head->getContext();
  llvm::BasicBlock *ThenBlock = llvm::BasicBlock::Create(
      C, NamePrefix + ".if.then", Head->getParent(), Head->getNextNode());
  llvm::BasicBlock *ElseBlock = llvm::BasicBlock::Create(
      C, NamePrefix + ".if.else", Head->getParent(), CanonicalLoop->getExit());
 
  // Create if condition branch.
  Builder.SetInsertPoint(HeadOldTerm);
  Instruction *BrInstr =
      Builder.CreateCondBr(IfCond, ThenBlock, /*ifFalse*/ ElseBlock);
  InsertPointTy IP{BrInstr->getParent(), ++BrInstr->getIterator()};
  // Then block contains branch to omp loop which needs to be vectorized
  spliceBB(IP, ThenBlock, false);
  ThenBlock->replaceSuccessorsPhiUsesWith(Head, ThenBlock);
 
  Builder.SetInsertPoint(ElseBlock);
 
  // Clone loop for the else branch
  SmallVector<BasicBlock *, 8> NewBlocks;
 
  VMap[CanonicalLoop->getPreheader()] = ElseBlock;
  for (BasicBlock *Block : L->getBlocks()) {
    BasicBlock *NewBB = CloneBasicBlock(Block, VMap, "", F);
    NewBB->moveBefore(CanonicalLoop->getExit());
    VMap[Block] = NewBB;
    NewBlocks.push_back(NewBB);
  }
  remapInstructionsInBlocks(NewBlocks, VMap);
  Builder.CreateBr(NewBlocks.front());
}
 
unsigned
OpenMPIRBuilder::getOpenMPDefaultSimdAlign(const Triple &TargetTriple,
                                           const StringMap<bool> &Features) {
  if (TargetTriple.isX86()) {
    if (Features.lookup("avx512f"))
      return 512;
    else if (Features.lookup("avx"))
      return 256;
    return 128;
  }
  if (TargetTriple.isPPC())
    return 128;
  if (TargetTriple.isWasm())
    return 128;
  return 0;
}
 
void OpenMPIRBuilder::applySimd(CanonicalLoopInfo *CanonicalLoop,
                                MapVector<Value *, Value *> AlignedVars,
                                Value *IfCond, OrderKind Order,
                                ConstantInt *Simdlen, ConstantInt *Safelen) {
  LLVMContext &Ctx = Builder.getContext();
 
  Function *F = CanonicalLoop->getFunction();
 
  // TODO: We should not rely on pass manager. Currently we use pass manager
  // only for getting llvm::Loop which corresponds to given CanonicalLoopInfo
  // object. We should have a method  which returns all blocks between
  // CanonicalLoopInfo::getHeader() and CanonicalLoopInfo::getAfter()
  FunctionAnalysisManager FAM;
  FAM.registerPass([]() { return DominatorTreeAnalysis(); });
  FAM.registerPass([]() { return LoopAnalysis(); });
  FAM.registerPass([]() { return PassInstrumentationAnalysis(); });
 
  LoopAnalysis LIA;
  LoopInfo &&LI = LIA.run(*F, FAM);
 
  Loop *L = LI.getLoopFor(CanonicalLoop->getHeader());
  if (AlignedVars.size()) {
    InsertPointTy IP = Builder.saveIP();
    Builder.SetInsertPoint(CanonicalLoop->getPreheader()->getTerminator());
    for (auto &AlignedItem : AlignedVars) {
      Value *AlignedPtr = AlignedItem.first;
      Value *Alignment = AlignedItem.second;
      Builder.CreateAlignmentAssumption(F->getParent()->getDataLayout(),
                                        AlignedPtr, Alignment);
    }
    Builder.restoreIP(IP);
  }
 
  if (IfCond) {
    ValueToValueMapTy VMap;
    createIfVersion(CanonicalLoop, IfCond, VMap, "simd");
    // Add metadata to the cloned loop which disables vectorization
    Value *MappedLatch = VMap.lookup(CanonicalLoop->getLatch());
    assert(MappedLatch &&
           "Cannot find value which corresponds to original loop latch");
    assert(isa<BasicBlock>(MappedLatch) &&
           "Cannot cast mapped latch block value to BasicBlock");
    BasicBlock *NewLatchBlock = dyn_cast<BasicBlock>(MappedLatch);
    ConstantAsMetadata *BoolConst =
        ConstantAsMetadata::get(ConstantInt::getFalse(Type::getInt1Ty(Ctx)));
    addBasicBlockMetadata(
        NewLatchBlock,
        {MDNode::get(Ctx, {MDString::get(Ctx, "llvm.loop.vectorize.enable"),
                           BoolConst})});
  }
 
  SmallSet<BasicBlock *, 8> Reachable;
 
  // Get the basic blocks from the loop in which memref instructions
  // can be found.
  // TODO: Generalize getting all blocks inside a CanonicalizeLoopInfo,
  // preferably without running any passes.
  for (BasicBlock *Block : L->getBlocks()) {
    if (Block == CanonicalLoop->getCond() ||
        Block == CanonicalLoop->getHeader())
      continue;
    Reachable.insert(Block);
  }
 
  SmallVector<Metadata *> LoopMDList;
 
  // In presence of finite 'safelen', it may be unsafe to mark all
  // the memory instructions parallel, because loop-carried
  // dependences of 'safelen' iterations are possible.
  // If clause order(concurrent) is specified then the memory instructions
  // are marked parallel even if 'safelen' is finite.
  if ((Safelen == nullptr) || (Order == OrderKind::OMP_ORDER_concurrent)) {
    // Add access group metadata to memory-access instructions.
    MDNode *AccessGroup = MDNode::getDistinct(Ctx, {});
    for (BasicBlock *BB : Reachable)
      addSimdMetadata(BB, AccessGroup, LI);
    // TODO:  If the loop has existing parallel access metadata, have
    // to combine two lists.
    LoopMDList.push_back(MDNode::get(
        Ctx, {MDString::get(Ctx, "llvm.loop.parallel_accesses"), AccessGroup}));
  }
 
  // Use the above access group metadata to create loop level
  // metadata, which should be distinct for each loop.
  ConstantAsMetadata *BoolConst =
      ConstantAsMetadata::get(ConstantInt::getTrue(Type::getInt1Ty(Ctx)));
  LoopMDList.push_back(MDNode::get(
      Ctx, {MDString::get(Ctx, "llvm.loop.vectorize.enable"), BoolConst}));
 
  if (Simdlen || Safelen) {
    // If both simdlen and safelen clauses are specified, the value of the
    // simdlen parameter must be less than or equal to the value of the safelen
    // parameter. Therefore, use safelen only in the absence of simdlen.
    ConstantInt *VectorizeWidth = Simdlen == nullptr ? Safelen : Simdlen;
    LoopMDList.push_back(
        MDNode::get(Ctx, {MDString::get(Ctx, "llvm.loop.vectorize.width"),
                          ConstantAsMetadata::get(VectorizeWidth)}));
  }
 
  addLoopMetadata(CanonicalLoop, LoopMDList);
}
 
/// Create the TargetMachine object to query the backend for optimization
/// preferences.
///
/// Ideally, this would be passed from the front-end to the OpenMPBuilder, but
/// e.g. Clang does not pass it to its CodeGen layer and creates it only when
/// needed for the LLVM pass pipline. We use some default options to avoid
/// having to pass too many settings from the frontend that probably do not
/// matter.
///
/// Currently, TargetMachine is only used sometimes by the unrollLoopPartial
/// method. If we are going to use TargetMachine for more purposes, especially
/// those that are sensitive to TargetOptions, RelocModel and CodeModel, it
/// might become be worth requiring front-ends to pass on their TargetMachine,
/// or at least cache it between methods. Note that while fontends such as Clang
/// have just a single main TargetMachine per translation unit, "target-cpu" and
/// "target-features" that determine the TargetMachine are per-function and can
/// be overrided using __attribute__((target("OPTIONS"))).
static std::unique_ptr<TargetMachine>
createTargetMachine(Function *F, CodeGenOpt::Level OptLevel) {
  Module *M = F->getParent();
 
  StringRef CPU = F->getFnAttribute("target-cpu").getValueAsString();
  StringRef Features = F->getFnAttribute("target-features").getValueAsString();
  const std::string &Triple = M->getTargetTriple();
 
  std::string Error;
  const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
  if (!TheTarget)
    return {};
 
  llvm::TargetOptions Options;
  return std::unique_ptr<TargetMachine>(TheTarget->createTargetMachine(
      Triple, CPU, Features, Options, /*RelocModel=*/std::nullopt,
      /*CodeModel=*/std::nullopt, OptLevel));
}
 
/// Heuristically determine the best-performant unroll factor for \p CLI. This
/// depends on the target processor. We are re-using the same heuristics as the
/// LoopUnrollPass.
static int32_t computeHeuristicUnrollFactor(CanonicalLoopInfo *CLI) {
  Function *F = CLI->getFunction();
 
  // Assume the user requests the most aggressive unrolling, even if the rest of
  // the code is optimized using a lower setting.
  CodeGenOpt::Level OptLevel = CodeGenOpt::Aggressive;
  std::unique_ptr<TargetMachine> TM = createTargetMachine(F, OptLevel);
 
  FunctionAnalysisManager FAM;
  FAM.registerPass([]() { return TargetLibraryAnalysis(); });
  FAM.registerPass([]() { return AssumptionAnalysis(); });
  FAM.registerPass([]() { return DominatorTreeAnalysis(); });
  FAM.registerPass([]() { return LoopAnalysis(); });
  FAM.registerPass([]() { return ScalarEvolutionAnalysis(); });
  FAM.registerPass([]() { return PassInstrumentationAnalysis(); });
  TargetIRAnalysis TIRA;
  if (TM)
    TIRA = TargetIRAnalysis(
        [&](const Function &F) { return TM->getTargetTransformInfo(F); });
  FAM.registerPass([&]() { return TIRA; });
 
  TargetIRAnalysis::Result &&TTI = TIRA.run(*F, FAM);
  ScalarEvolutionAnalysis SEA;
  ScalarEvolution &&SE = SEA.run(*F, FAM);
  DominatorTreeAnalysis DTA;
  DominatorTree &&DT = DTA.run(*F, FAM);
  LoopAnalysis LIA;
  LoopInfo &&LI = LIA.run(*F, FAM);
  AssumptionAnalysis ACT;
  AssumptionCache &&AC = ACT.run(*F, FAM);
  OptimizationRemarkEmitter ORE{F};
 
  Loop *L = LI.getLoopFor(CLI->getHeader());
  assert(L && "Expecting CanonicalLoopInfo to be recognized as a loop");
 
  TargetTransformInfo::UnrollingPreferences UP =
      gatherUnrollingPreferences(L, SE, TTI,
                                 /*BlockFrequencyInfo=*/nullptr,
                                 /*ProfileSummaryInfo=*/nullptr, ORE, OptLevel,
                                 /*UserThreshold=*/std::nullopt,
                                 /*UserCount=*/std::nullopt,
                                 /*UserAllowPartial=*/true,
                                 /*UserAllowRuntime=*/true,
                                 /*UserUpperBound=*/std::nullopt,
                                 /*UserFullUnrollMaxCount=*/std::nullopt);
 
  UP.Force = true;
 
  // Account for additional optimizations taking place before the LoopUnrollPass
  // would unroll the loop.
  UP.Threshold *= UnrollThresholdFactor;
  UP.PartialThreshold *= UnrollThresholdFactor;
 
  // Use normal unroll factors even if the rest of the code is optimized for
  // size.
  UP.OptSizeThreshold = UP.Threshold;
  UP.PartialOptSizeThreshold = UP.PartialThreshold;
 
  LLVM_DEBUG(dbgs() << "Unroll heuristic thresholds:\n"
                    << "  Threshold=" << UP.Threshold << "\n"
                    << "  PartialThreshold=" << UP.PartialThreshold << "\n"
                    << "  OptSizeThreshold=" << UP.OptSizeThreshold << "\n"
                    << "  PartialOptSizeThreshold="
                    << UP.PartialOptSizeThreshold << "\n");
 
  // Disable peeling.
  TargetTransformInfo::PeelingPreferences PP =
      gatherPeelingPreferences(L, SE, TTI,
                               /*UserAllowPeeling=*/false,
                               /*UserAllowProfileBasedPeeling=*/false,
                               /*UnrollingSpecficValues=*/false);
 
  SmallPtrSet<const Value *, 32> EphValues;
  CodeMetrics::collectEphemeralValues(L, &AC, EphValues);
 
  // Assume that reads and writes to stack variables can be eliminated by
  // Mem2Reg, SROA or LICM. That is, don't count them towards the loop body's
  // size.
  for (BasicBlock *BB : L->blocks()) {
    for (Instruction &I : *BB) {
      Value *Ptr;
      if (auto *Load = dyn_cast<LoadInst>(&I)) {
        Ptr = Load->getPointerOperand();
      } else if (auto *Store = dyn_cast<StoreInst>(&I)) {
        Ptr = Store->getPointerOperand();
      } else
        continue;
 
      Ptr = Ptr->stripPointerCasts();
 
      if (auto *Alloca = dyn_cast<AllocaInst>(Ptr)) {
        if (Alloca->getParent() == &F->getEntryBlock())
          EphValues.insert(&I);
      }
    }
  }
 
  unsigned NumInlineCandidates;
  bool NotDuplicatable;
  bool Convergent;
  InstructionCost LoopSizeIC =
      ApproximateLoopSize(L, NumInlineCandidates, NotDuplicatable, Convergent,
                          TTI, EphValues, UP.BEInsns);
  LLVM_DEBUG(dbgs() << "Estimated loop size is " << LoopSizeIC << "\n");
 
  // Loop is not unrollable if the loop contains certain instructions.
  if (NotDuplicatable || Convergent || !LoopSizeIC.isValid()) {
    LLVM_DEBUG(dbgs() << "Loop not considered unrollable\n");
    return 1;
  }
  unsigned LoopSize = *LoopSizeIC.getValue();
 
  // TODO: Determine trip count of \p CLI if constant, computeUnrollCount might
  // be able to use it.
  int TripCount = 0;
  int MaxTripCount = 0;
  bool MaxOrZero = false;
  unsigned TripMultiple = 0;
 
  bool UseUpperBound = false;
  computeUnrollCount(L, TTI, DT, &LI, &AC, SE, EphValues, &ORE, TripCount,
                     MaxTripCount, MaxOrZero, TripMultiple, LoopSize, UP, PP,
                     UseUpperBound);
  unsigned Factor = UP.Count;
  LLVM_DEBUG(dbgs() << "Suggesting unroll factor of " << Factor << "\n");
 
  // This function returns 1 to signal to not unroll a loop.
  if (Factor == 0)
    return 1;
  return Factor;
}
 
void OpenMPIRBuilder::unrollLoopPartial(DebugLoc DL, CanonicalLoopInfo *Loop,
                                        int32_t Factor,
                                        CanonicalLoopInfo **UnrolledCLI) {
  assert(Factor >= 0 && "Unroll factor must not be negative");
 
  Function *F = Loop->getFunction();
  LLVMContext &Ctx = F->getContext();
 
  // If the unrolled loop is not used for another loop-associated directive, it
  // is sufficient to add metadata for the LoopUnrollPass.
  if (!UnrolledCLI) {
    SmallVector<Metadata *, 2> LoopMetadata;
    LoopMetadata.push_back(
        MDNode::get(Ctx, MDString::get(Ctx, "llvm.loop.unroll.enable")));
 
    if (Factor >= 1) {
      ConstantAsMetadata *FactorConst = ConstantAsMetadata::get(
          ConstantInt::get(Type::getInt32Ty(Ctx), APInt(32, Factor)));
      LoopMetadata.push_back(MDNode::get(
          Ctx, {MDString::get(Ctx, "llvm.loop.unroll.count"), FactorConst}));
    }
 
    addLoopMetadata(Loop, LoopMetadata);
    return;
  }
 
  // Heuristically determine the unroll factor.
  if (Factor == 0)
    Factor = computeHeuristicUnrollFactor(Loop);
 
  // No change required with unroll factor 1.
  if (Factor == 1) {
    *UnrolledCLI = Loop;
    return;
  }
 
  assert(Factor >= 2 &&
         "unrolling only makes sense with a factor of 2 or larger");
 
  Type *IndVarTy = Loop->getIndVarType();
 
  // Apply partial unrolling by tiling the loop by the unroll-factor, then fully
  // unroll the inner loop.
  Value *FactorVal =
      ConstantInt::get(IndVarTy, APInt(IndVarTy->getIntegerBitWidth(), Factor,
                                       /*isSigned=*/false));
  std::vector<CanonicalLoopInfo *> LoopNest =
      tileLoops(DL, {Loop}, {FactorVal});
  assert(LoopNest.size() == 2 && "Expect 2 loops after tiling");
  *UnrolledCLI = LoopNest[0];
  CanonicalLoopInfo *InnerLoop = LoopNest[1];
 
  // LoopUnrollPass can only fully unroll loops with constant trip count.
  // Unroll by the unroll factor with a fallback epilog for the remainder
  // iterations if necessary.
  ConstantAsMetadata *FactorConst = ConstantAsMetadata::get(
      ConstantInt::get(Type::getInt32Ty(Ctx), APInt(32, Factor)));
  addLoopMetadata(
      InnerLoop,
      {MDNode::get(Ctx, MDString::get(Ctx, "llvm.loop.unroll.enable")),
       MDNode::get(
           Ctx, {MDString::get(Ctx, "llvm.loop.unroll.count"), FactorConst})});
 
#ifndef NDEBUG
  (*UnrolledCLI)->assertOK();
#endif
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createCopyPrivate(const LocationDescription &Loc,
                                   llvm::Value *BufSize, llvm::Value *CpyBuf,
                                   llvm::Value *CpyFn, llvm::Value *DidIt) {
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
 
  llvm::Value *DidItLD = Builder.CreateLoad(Builder.getInt32Ty(), DidIt);
 
  Value *Args[] = {Ident, ThreadId, BufSize, CpyBuf, CpyFn, DidItLD};
 
  Function *Fn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_copyprivate);
  Builder.CreateCall(Fn, Args);
 
  return Builder.saveIP();
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::createSingle(
    const LocationDescription &Loc, BodyGenCallbackTy BodyGenCB,
    FinalizeCallbackTy FiniCB, bool IsNowait, llvm::Value *DidIt) {
 
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  // If needed (i.e. not null), initialize `DidIt` with 0
  if (DidIt) {
    Builder.CreateStore(Builder.getInt32(0), DidIt);
  }
 
  Directive OMPD = Directive::OMPD_single;
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  Value *Args[] = {Ident, ThreadId};
 
  Function *EntryRTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_single);
  Instruction *EntryCall = Builder.CreateCall(EntryRTLFn, Args);
 
  Function *ExitRTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_end_single);
  Instruction *ExitCall = Builder.CreateCall(ExitRTLFn, Args);
 
  // generates the following:
  // if (__kmpc_single()) {
  //    .... single region ...
  //    __kmpc_end_single
  // }
  // __kmpc_barrier
 
  EmitOMPInlinedRegion(OMPD, EntryCall, ExitCall, BodyGenCB, FiniCB,
                       /*Conditional*/ true,
                       /*hasFinalize*/ true);
  if (!IsNowait)
    createBarrier(LocationDescription(Builder.saveIP(), Loc.DL),
                  omp::Directive::OMPD_unknown, /* ForceSimpleCall */ false,
                  /* CheckCancelFlag */ false);
  return Builder.saveIP();
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::createCritical(
    const LocationDescription &Loc, BodyGenCallbackTy BodyGenCB,
    FinalizeCallbackTy FiniCB, StringRef CriticalName, Value *HintInst) {
 
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  Directive OMPD = Directive::OMPD_critical;
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  Value *LockVar = getOMPCriticalRegionLock(CriticalName);
  Value *Args[] = {Ident, ThreadId, LockVar};
 
  SmallVector<llvm::Value *, 4> EnterArgs(std::begin(Args), std::end(Args));
  Function *RTFn = nullptr;
  if (HintInst) {
    // Add Hint to entry Args and create call
    EnterArgs.push_back(HintInst);
    RTFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_critical_with_hint);
  } else {
    RTFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_critical);
  }
  Instruction *EntryCall = Builder.CreateCall(RTFn, EnterArgs);
 
  Function *ExitRTLFn =
      getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_end_critical);
  Instruction *ExitCall = Builder.CreateCall(ExitRTLFn, Args);
 
  return EmitOMPInlinedRegion(OMPD, EntryCall, ExitCall, BodyGenCB, FiniCB,
                              /*Conditional*/ false, /*hasFinalize*/ true);
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createOrderedDepend(const LocationDescription &Loc,
                                     InsertPointTy AllocaIP, unsigned NumLoops,
                                     ArrayRef<llvm::Value *> StoreValues,
                                     const Twine &Name, bool IsDependSource) {
  assert(
      llvm::all_of(StoreValues,
                   [](Value *SV) { return SV->getType()->isIntegerTy(64); }) &&
      "OpenMP runtime requires depend vec with i64 type");
 
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  // Allocate space for vector and generate alloc instruction.
  auto *ArrI64Ty = ArrayType::get(Int64, NumLoops);
  Builder.restoreIP(AllocaIP);
  AllocaInst *ArgsBase = Builder.CreateAlloca(ArrI64Ty, nullptr, Name);
  ArgsBase->setAlignment(Align(8));
  Builder.restoreIP(Loc.IP);
 
  // Store the index value with offset in depend vector.
  for (unsigned I = 0; I < NumLoops; ++I) {
    Value *DependAddrGEPIter = Builder.CreateInBoundsGEP(
        ArrI64Ty, ArgsBase, {Builder.getInt64(0), Builder.getInt64(I)});
    StoreInst *STInst = Builder.CreateStore(StoreValues[I], DependAddrGEPIter);
    STInst->setAlignment(Align(8));
  }
 
  Value *DependBaseAddrGEP = Builder.CreateInBoundsGEP(
      ArrI64Ty, ArgsBase, {Builder.getInt64(0), Builder.getInt64(0)});
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  Value *Args[] = {Ident, ThreadId, DependBaseAddrGEP};
 
  Function *RTLFn = nullptr;
  if (IsDependSource)
    RTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_doacross_post);
  else
    RTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_doacross_wait);
  Builder.CreateCall(RTLFn, Args);
 
  return Builder.saveIP();
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::createOrderedThreadsSimd(
    const LocationDescription &Loc, BodyGenCallbackTy BodyGenCB,
    FinalizeCallbackTy FiniCB, bool IsThreads) {
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  Directive OMPD = Directive::OMPD_ordered;
  Instruction *EntryCall = nullptr;
  Instruction *ExitCall = nullptr;
 
  if (IsThreads) {
    uint32_t SrcLocStrSize;
    Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
    Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
    Value *ThreadId = getOrCreateThreadID(Ident);
    Value *Args[] = {Ident, ThreadId};
 
    Function *EntryRTLFn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_ordered);
    EntryCall = Builder.CreateCall(EntryRTLFn, Args);
 
    Function *ExitRTLFn =
        getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_end_ordered);
    ExitCall = Builder.CreateCall(ExitRTLFn, Args);
  }
 
  return EmitOMPInlinedRegion(OMPD, EntryCall, ExitCall, BodyGenCB, FiniCB,
                              /*Conditional*/ false, /*hasFinalize*/ true);
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::EmitOMPInlinedRegion(
    Directive OMPD, Instruction *EntryCall, Instruction *ExitCall,
    BodyGenCallbackTy BodyGenCB, FinalizeCallbackTy FiniCB, bool Conditional,
    bool HasFinalize, bool IsCancellable) {
 
  if (HasFinalize)
    FinalizationStack.push_back({FiniCB, OMPD, IsCancellable});
 
  // Create inlined region's entry and body blocks, in preparation
  // for conditional creation
  BasicBlock *EntryBB = Builder.GetInsertBlock();
  Instruction *SplitPos = EntryBB->getTerminator();
  if (!isa_and_nonnull<BranchInst>(SplitPos))
    SplitPos = new UnreachableInst(Builder.getContext(), EntryBB);
  BasicBlock *ExitBB = EntryBB->splitBasicBlock(SplitPos, "omp_region.end");
  BasicBlock *FiniBB =
      EntryBB->splitBasicBlock(EntryBB->getTerminator(), "omp_region.finalize");
 
  Builder.SetInsertPoint(EntryBB->getTerminator());
  emitCommonDirectiveEntry(OMPD, EntryCall, ExitBB, Conditional);
 
  // generate body
  BodyGenCB(/* AllocaIP */ InsertPointTy(),
            /* CodeGenIP */ Builder.saveIP());
 
  // emit exit call and do any needed finalization.
  auto FinIP = InsertPointTy(FiniBB, FiniBB->getFirstInsertionPt());
  assert(FiniBB->getTerminator()->getNumSuccessors() == 1 &&
         FiniBB->getTerminator()->getSuccessor(0) == ExitBB &&
         "Unexpected control flow graph state!!");
  emitCommonDirectiveExit(OMPD, FinIP, ExitCall, HasFinalize);
  assert(FiniBB->getUniquePredecessor()->getUniqueSuccessor() == FiniBB &&
         "Unexpected Control Flow State!");
  MergeBlockIntoPredecessor(FiniBB);
 
  // If we are skipping the region of a non conditional, remove the exit
  // block, and clear the builder's insertion point.
  assert(SplitPos->getParent() == ExitBB &&
         "Unexpected Insertion point location!");
  auto merged = MergeBlockIntoPredecessor(ExitBB);
  BasicBlock *ExitPredBB = SplitPos->getParent();
  auto InsertBB = merged ? ExitPredBB : ExitBB;
  if (!isa_and_nonnull<BranchInst>(SplitPos))
    SplitPos->eraseFromParent();
  Builder.SetInsertPoint(InsertBB);
 
  return Builder.saveIP();
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::emitCommonDirectiveEntry(
    Directive OMPD, Value *EntryCall, BasicBlock *ExitBB, bool Conditional) {
  // if nothing to do, Return current insertion point.
  if (!Conditional || !EntryCall)
    return Builder.saveIP();
 
  BasicBlock *EntryBB = Builder.GetInsertBlock();
  Value *CallBool = Builder.CreateIsNotNull(EntryCall);
  auto *ThenBB = BasicBlock::Create(M.getContext(), "omp_region.body");
  auto *UI = new UnreachableInst(Builder.getContext(), ThenBB);
 
  // Emit thenBB and set the Builder's insertion point there for
  // body generation next. Place the block after the current block.
  Function *CurFn = EntryBB->getParent();
  CurFn->insert(std::next(EntryBB->getIterator()), ThenBB);
 
  // Move Entry branch to end of ThenBB, and replace with conditional
  // branch (If-stmt)
  Instruction *EntryBBTI = EntryBB->getTerminator();
  Builder.CreateCondBr(CallBool, ThenBB, ExitBB);
  EntryBBTI->removeFromParent();
  Builder.SetInsertPoint(UI);
  Builder.Insert(EntryBBTI);
  UI->eraseFromParent();
  Builder.SetInsertPoint(ThenBB->getTerminator());
 
  // return an insertion point to ExitBB.
  return IRBuilder<>::InsertPoint(ExitBB, ExitBB->getFirstInsertionPt());
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::emitCommonDirectiveExit(
    omp::Directive OMPD, InsertPointTy FinIP, Instruction *ExitCall,
    bool HasFinalize) {
 
  Builder.restoreIP(FinIP);
 
  // If there is finalization to do, emit it before the exit call
  if (HasFinalize) {
    assert(!FinalizationStack.empty() &&
           "Unexpected finalization stack state!");
 
    FinalizationInfo Fi = FinalizationStack.pop_back_val();
    assert(Fi.DK == OMPD && "Unexpected Directive for Finalization call!");
 
    Fi.FiniCB(FinIP);
 
    BasicBlock *FiniBB = FinIP.getBlock();
    Instruction *FiniBBTI = FiniBB->getTerminator();
 
    // set Builder IP for call creation
    Builder.SetInsertPoint(FiniBBTI);
  }
 
  if (!ExitCall)
    return Builder.saveIP();
 
  // place the Exitcall as last instruction before Finalization block terminator
  ExitCall->removeFromParent();
  Builder.Insert(ExitCall);
 
  return IRBuilder<>::InsertPoint(ExitCall->getParent(),
                                  ExitCall->getIterator());
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::createCopyinClauseBlocks(
    InsertPointTy IP, Value *MasterAddr, Value *PrivateAddr,
    llvm::IntegerType *IntPtrTy, bool BranchtoEnd) {
  if (!IP.isSet())
    return IP;
 
  IRBuilder<>::InsertPointGuard IPG(Builder);
 
  // creates the following CFG structure
  //     OMP_Entry : (MasterAddr != PrivateAddr)?
  //       F     T
  //       |      \
  //       |     copin.not.master
  //       |      /
  //       v     /
  //   copyin.not.master.end
  //         |
  //         v
  //   OMP.Entry.Next
 
  BasicBlock *OMP_Entry = IP.getBlock();
  Function *CurFn = OMP_Entry->getParent();
  BasicBlock *CopyBegin =
      BasicBlock::Create(M.getContext(), "copyin.not.master", CurFn);
  BasicBlock *CopyEnd = nullptr;
 
  // If entry block is terminated, split to preserve the branch to following
  // basic block (i.e. OMP.Entry.Next), otherwise, leave everything as is.
  if (isa_and_nonnull<BranchInst>(OMP_Entry->getTerminator())) {
    CopyEnd = OMP_Entry->splitBasicBlock(OMP_Entry->getTerminator(),
                                         "copyin.not.master.end");
    OMP_Entry->getTerminator()->eraseFromParent();
  } else {
    CopyEnd =
        BasicBlock::Create(M.getContext(), "copyin.not.master.end", CurFn);
  }
 
  Builder.SetInsertPoint(OMP_Entry);
  Value *MasterPtr = Builder.CreatePtrToInt(MasterAddr, IntPtrTy);
  Value *PrivatePtr = Builder.CreatePtrToInt(PrivateAddr, IntPtrTy);
  Value *cmp = Builder.CreateICmpNE(MasterPtr, PrivatePtr);
  Builder.CreateCondBr(cmp, CopyBegin, CopyEnd);
 
  Builder.SetInsertPoint(CopyBegin);
  if (BranchtoEnd)
    Builder.SetInsertPoint(Builder.CreateBr(CopyEnd));
 
  return Builder.saveIP();
}
 
CallInst *OpenMPIRBuilder::createOMPAlloc(const LocationDescription &Loc,
                                          Value *Size, Value *Allocator,
                                          std::string Name) {
  IRBuilder<>::InsertPointGuard IPG(Builder);
  Builder.restoreIP(Loc.IP);
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  Value *Args[] = {ThreadId, Size, Allocator};
 
  Function *Fn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_alloc);
 
  return Builder.CreateCall(Fn, Args, Name);
}
 
CallInst *OpenMPIRBuilder::createOMPFree(const LocationDescription &Loc,
                                         Value *Addr, Value *Allocator,
                                         std::string Name) {
  IRBuilder<>::InsertPointGuard IPG(Builder);
  Builder.restoreIP(Loc.IP);
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  Value *Args[] = {ThreadId, Addr, Allocator};
  Function *Fn = getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_free);
  return Builder.CreateCall(Fn, Args, Name);
}
 
CallInst *OpenMPIRBuilder::createOMPInteropInit(
    const LocationDescription &Loc, Value *InteropVar,
    omp::OMPInteropType InteropType, Value *Device, Value *NumDependences,
    Value *DependenceAddress, bool HaveNowaitClause) {
  IRBuilder<>::InsertPointGuard IPG(Builder);
  Builder.restoreIP(Loc.IP);
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  if (Device == nullptr)
    Device = ConstantInt::get(Int32, -1);
  Constant *InteropTypeVal = ConstantInt::get(Int32, (int)InteropType);
  if (NumDependences == nullptr) {
    NumDependences = ConstantInt::get(Int64, 0);
    PointerType *PointerTypeVar = Type::getInt8PtrTy(M.getContext());
    DependenceAddress = ConstantPointerNull::get(PointerTypeVar);
  }
  Value *HaveNowaitClauseVal = ConstantInt::get(Int32, HaveNowaitClause);
  Value *Args[] = {
      Ident,  ThreadId,       InteropVar,        InteropTypeVal,
      Device, NumDependences, DependenceAddress, HaveNowaitClauseVal};
 
  Function *Fn = getOrCreateRuntimeFunctionPtr(OMPRTL___tgt_interop_init);
 
  return Builder.CreateCall(Fn, Args);
}
 
CallInst *OpenMPIRBuilder::createOMPInteropDestroy(
    const LocationDescription &Loc, Value *InteropVar, Value *Device,
    Value *NumDependences, Value *DependenceAddress, bool HaveNowaitClause) {
  IRBuilder<>::InsertPointGuard IPG(Builder);
  Builder.restoreIP(Loc.IP);
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  if (Device == nullptr)
    Device = ConstantInt::get(Int32, -1);
  if (NumDependences == nullptr) {
    NumDependences = ConstantInt::get(Int32, 0);
    PointerType *PointerTypeVar = Type::getInt8PtrTy(M.getContext());
    DependenceAddress = ConstantPointerNull::get(PointerTypeVar);
  }
  Value *HaveNowaitClauseVal = ConstantInt::get(Int32, HaveNowaitClause);
  Value *Args[] = {
      Ident,          ThreadId,          InteropVar,         Device,
      NumDependences, DependenceAddress, HaveNowaitClauseVal};
 
  Function *Fn = getOrCreateRuntimeFunctionPtr(OMPRTL___tgt_interop_destroy);
 
  return Builder.CreateCall(Fn, Args);
}
 
CallInst *OpenMPIRBuilder::createOMPInteropUse(const LocationDescription &Loc,
                                               Value *InteropVar, Value *Device,
                                               Value *NumDependences,
                                               Value *DependenceAddress,
                                               bool HaveNowaitClause) {
  IRBuilder<>::InsertPointGuard IPG(Builder);
  Builder.restoreIP(Loc.IP);
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  if (Device == nullptr)
    Device = ConstantInt::get(Int32, -1);
  if (NumDependences == nullptr) {
    NumDependences = ConstantInt::get(Int32, 0);
    PointerType *PointerTypeVar = Type::getInt8PtrTy(M.getContext());
    DependenceAddress = ConstantPointerNull::get(PointerTypeVar);
  }
  Value *HaveNowaitClauseVal = ConstantInt::get(Int32, HaveNowaitClause);
  Value *Args[] = {
      Ident,          ThreadId,          InteropVar,         Device,
      NumDependences, DependenceAddress, HaveNowaitClauseVal};
 
  Function *Fn = getOrCreateRuntimeFunctionPtr(OMPRTL___tgt_interop_use);
 
  return Builder.CreateCall(Fn, Args);
}
 
CallInst *OpenMPIRBuilder::createCachedThreadPrivate(
    const LocationDescription &Loc, llvm::Value *Pointer,
    llvm::ConstantInt *Size, const llvm::Twine &Name) {
  IRBuilder<>::InsertPointGuard IPG(Builder);
  Builder.restoreIP(Loc.IP);
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  Value *ThreadId = getOrCreateThreadID(Ident);
  Constant *ThreadPrivateCache =
      getOrCreateInternalVariable(Int8PtrPtr, Name.str());
  llvm::Value *Args[] = {Ident, ThreadId, Pointer, Size, ThreadPrivateCache};
 
  Function *Fn =
      getOrCreateRuntimeFunctionPtr(OMPRTL___kmpc_threadprivate_cached);
 
  return Builder.CreateCall(Fn, Args);
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createTargetInit(const LocationDescription &Loc, bool IsSPMD) {
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Constant *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  ConstantInt *IsSPMDVal = ConstantInt::getSigned(
      IntegerType::getInt8Ty(Int8->getContext()),
      IsSPMD ? OMP_TGT_EXEC_MODE_SPMD : OMP_TGT_EXEC_MODE_GENERIC);
  ConstantInt *UseGenericStateMachine =
      ConstantInt::getBool(Int32->getContext(), !IsSPMD);
 
  Function *Fn = getOrCreateRuntimeFunctionPtr(
      omp::RuntimeFunction::OMPRTL___kmpc_target_init);
 
  CallInst *ThreadKind = Builder.CreateCall(
      Fn, {Ident, IsSPMDVal, UseGenericStateMachine});
 
  Value *ExecUserCode = Builder.CreateICmpEQ(
      ThreadKind, ConstantInt::get(ThreadKind->getType(), -1),
      "exec_user_code");
 
  // ThreadKind = __kmpc_target_init(...)
  // if (ThreadKind == -1)
  //   user_code
  // else
  //   return;
 
  auto *UI = Builder.CreateUnreachable();
  BasicBlock *CheckBB = UI->getParent();
  BasicBlock *UserCodeEntryBB = CheckBB->splitBasicBlock(UI, "user_code.entry");
 
  BasicBlock *WorkerExitBB = BasicBlock::Create(
      CheckBB->getContext(), "worker.exit", CheckBB->getParent());
  Builder.SetInsertPoint(WorkerExitBB);
  Builder.CreateRetVoid();
 
  auto *CheckBBTI = CheckBB->getTerminator();
  Builder.SetInsertPoint(CheckBBTI);
  Builder.CreateCondBr(ExecUserCode, UI->getParent(), WorkerExitBB);
 
  CheckBBTI->eraseFromParent();
  UI->eraseFromParent();
 
  // Continue in the "user_code" block, see diagram above and in
  // openmp/libomptarget/deviceRTLs/common/include/target.h .
  return InsertPointTy(UserCodeEntryBB, UserCodeEntryBB->getFirstInsertionPt());
}
 
void OpenMPIRBuilder::createTargetDeinit(const LocationDescription &Loc,
                                         bool IsSPMD) {
  if (!updateToLocation(Loc))
    return;
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
  ConstantInt *IsSPMDVal = ConstantInt::getSigned(
      IntegerType::getInt8Ty(Int8->getContext()),
      IsSPMD ? OMP_TGT_EXEC_MODE_SPMD : OMP_TGT_EXEC_MODE_GENERIC);
 
  Function *Fn = getOrCreateRuntimeFunctionPtr(
      omp::RuntimeFunction::OMPRTL___kmpc_target_deinit);
 
  Builder.CreateCall(Fn, {Ident, IsSPMDVal});
}
 
void OpenMPIRBuilder::setOutlinedTargetRegionFunctionAttributes(
    Function *OutlinedFn, int32_t NumTeams, int32_t NumThreads) {
  if (Config.isEmbedded()) {
    OutlinedFn->setLinkage(GlobalValue::WeakODRLinkage);
    // TODO: Determine if DSO local can be set to true.
    OutlinedFn->setDSOLocal(false);
    OutlinedFn->setVisibility(GlobalValue::ProtectedVisibility);
    if (Triple(M.getTargetTriple()).isAMDGCN())
      OutlinedFn->setCallingConv(CallingConv::AMDGPU_KERNEL);
  }
 
  if (NumTeams > 0)
    OutlinedFn->addFnAttr("omp_target_num_teams", std::to_string(NumTeams));
  if (NumThreads > 0)
    OutlinedFn->addFnAttr("omp_target_thread_limit",
                          std::to_string(NumThreads));
}
 
Constant *OpenMPIRBuilder::createOutlinedFunctionID(Function *OutlinedFn,
                                                    StringRef EntryFnIDName) {
  if (Config.isEmbedded()) {
    assert(OutlinedFn && "The outlined function must exist if embedded");
    return ConstantExpr::getBitCast(OutlinedFn, Builder.getInt8PtrTy());
  }
 
  return new GlobalVariable(
      M, Builder.getInt8Ty(), /*isConstant=*/true, GlobalValue::WeakAnyLinkage,
      Constant::getNullValue(Builder.getInt8Ty()), EntryFnIDName);
}
 
Constant *OpenMPIRBuilder::createTargetRegionEntryAddr(Function *OutlinedFn,
                                                       StringRef EntryFnName) {
  if (OutlinedFn)
    return OutlinedFn;
 
  assert(!M.getGlobalVariable(EntryFnName, true) &&
         "Named kernel already exists?");
  return new GlobalVariable(
      M, Builder.getInt8Ty(), /*isConstant=*/true, GlobalValue::InternalLinkage,
      Constant::getNullValue(Builder.getInt8Ty()), EntryFnName);
}
 
void OpenMPIRBuilder::emitTargetRegionFunction(
    OffloadEntriesInfoManager &InfoManager, TargetRegionEntryInfo &EntryInfo,
    FunctionGenCallback &GenerateFunctionCallback, int32_t NumTeams,
    int32_t NumThreads, bool IsOffloadEntry, Function *&OutlinedFn,
    Constant *&OutlinedFnID) {
 
  SmallString<64> EntryFnName;
  InfoManager.getTargetRegionEntryFnName(EntryFnName, EntryInfo);
 
  OutlinedFn = Config.isEmbedded() || !Config.openMPOffloadMandatory()
                   ? GenerateFunctionCallback(EntryFnName)
                   : nullptr;
 
  // If this target outline function is not an offload entry, we don't need to
  // register it. This may be in the case of a false if clause, or if there are
  // no OpenMP targets.
  if (!IsOffloadEntry)
    return;
 
  std::string EntryFnIDName =
      Config.isEmbedded()
          ? std::string(EntryFnName)
          : createPlatformSpecificName({EntryFnName, "region_id"});
 
  OutlinedFnID = registerTargetRegionFunction(
      InfoManager, EntryInfo, OutlinedFn, EntryFnName, EntryFnIDName, NumTeams,
      NumThreads);
}
 
Constant *OpenMPIRBuilder::registerTargetRegionFunction(
    OffloadEntriesInfoManager &InfoManager, TargetRegionEntryInfo &EntryInfo,
    Function *OutlinedFn, StringRef EntryFnName, StringRef EntryFnIDName,
    int32_t NumTeams, int32_t NumThreads) {
  if (OutlinedFn)
    setOutlinedTargetRegionFunctionAttributes(OutlinedFn, NumTeams, NumThreads);
  auto OutlinedFnID = createOutlinedFunctionID(OutlinedFn, EntryFnIDName);
  auto EntryAddr = createTargetRegionEntryAddr(OutlinedFn, EntryFnName);
  InfoManager.registerTargetRegionEntryInfo(
      EntryInfo, EntryAddr, OutlinedFnID,
      OffloadEntriesInfoManager::OMPTargetRegionEntryTargetRegion);
  return OutlinedFnID;
}
 
OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::createTargetData(
    const LocationDescription &Loc, OpenMPIRBuilder::InsertPointTy CodeGenIP,
    SmallVectorImpl<uint64_t> &MapTypeFlags,
    SmallVectorImpl<Constant *> &MapNames, struct MapperAllocas &MapperAllocas,
    bool IsBegin, int64_t DeviceID, Value *IfCond,
    BodyGenCallbackTy ProcessMapOpCB, BodyGenCallbackTy BodyGenCB) {
  if (!updateToLocation(Loc))
    return InsertPointTy();
 
  Builder.restoreIP(CodeGenIP);
 
  // LLVM utilities like blocks with terminators.
  // The UI acts as a resume point for code insertion after the BodyGen
  auto *UI = Builder.CreateUnreachable();
  if (IfCond) {
    auto *ThenTI =
        SplitBlockAndInsertIfThen(IfCond, UI, /* Unreachable */ false);
    ThenTI->getParent()->setName("omp_if.then");
    Builder.SetInsertPoint(ThenTI);
  } else {
    Builder.SetInsertPoint(UI);
  }
 
  ProcessMapOpCB(Builder.saveIP(), Builder.saveIP());
 
  uint32_t SrcLocStrSize;
  Constant *SrcLocStr = getOrCreateSrcLocStr(Loc, SrcLocStrSize);
  Value *srcLocInfo = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
 
  GlobalVariable *MapTypesGV =
      createOffloadMaptypes(MapTypeFlags, ".offload_maptypes");
  Value *MapTypesArg = Builder.CreateConstInBoundsGEP2_32(
      ArrayType::get(Builder.getInt64Ty(), MapTypeFlags.size()), MapTypesGV,
      /*Idx0=*/0, /*Idx1=*/0);
 
  GlobalVariable *MapNamesGV =
      createOffloadMapnames(MapNames, ".offload_mapnames");
  Value *MapNamesArg = Builder.CreateConstInBoundsGEP2_32(
      ArrayType::get(Builder.getInt8PtrTy(), MapNames.size()), MapNamesGV,
      /*Idx0=*/0, /*Idx1=*/0);
 
  Function *beginMapperFunc =
      getOrCreateRuntimeFunctionPtr(omp::OMPRTL___tgt_target_data_begin_mapper);
  Function *endMapperFunc =
      getOrCreateRuntimeFunctionPtr(omp::OMPRTL___tgt_target_data_end_mapper);
 
  if (BodyGenCB) {
    // Create call to start the data region.
    emitMapperCall(Builder.saveIP(), beginMapperFunc, srcLocInfo, MapTypesArg,
                   MapNamesArg, MapperAllocas, DeviceID, MapTypeFlags.size());
 
    BodyGenCB(Builder.saveIP(), Builder.saveIP());
 
    Builder.SetInsertPoint(UI->getParent());
    // Create call to end the data region.
    emitMapperCall(Builder.saveIP(), endMapperFunc, srcLocInfo, MapTypesArg,
                   MapNamesArg, MapperAllocas, DeviceID, MapTypeFlags.size());
  } else {
    emitMapperCall(Builder.saveIP(), IsBegin ? beginMapperFunc : endMapperFunc,
                   srcLocInfo, MapTypesArg, MapNamesArg, MapperAllocas,
                   DeviceID, MapTypeFlags.size());
  }
 
  // Update the insertion point and remove the terminator we introduced.
  Builder.SetInsertPoint(UI->getParent());
  if (IfCond)
    UI->getParent()->setName("omp_if.end");
  UI->eraseFromParent();
  return Builder.saveIP();
}
 
std::string OpenMPIRBuilder::getNameWithSeparators(ArrayRef<StringRef> Parts,
                                                   StringRef FirstSeparator,
                                                   StringRef Separator) {
  SmallString<128> Buffer;
  llvm::raw_svector_ostream OS(Buffer);
  StringRef Sep = FirstSeparator;
  for (StringRef Part : Parts) {
    OS << Sep << Part;
    Sep = Separator;
  }
  return OS.str().str();
}
 
std::string
OpenMPIRBuilder::createPlatformSpecificName(ArrayRef<StringRef> Parts) const {
  return OpenMPIRBuilder::getNameWithSeparators(Parts, Config.firstSeparator(),
                                                Config.separator());
}
 
GlobalVariable *
OpenMPIRBuilder::getOrCreateInternalVariable(Type *Ty, const StringRef &Name,
                                             unsigned AddressSpace) {
  auto &Elem = *InternalVars.try_emplace(Name, nullptr).first;
  if (Elem.second) {
    assert(cast<PointerType>(Elem.second->getType())
               ->isOpaqueOrPointeeTypeMatches(Ty) &&
           "OMP internal variable has different type than requested");
  } else {
    // TODO: investigate the appropriate linkage type used for the global
    // variable for possibly changing that to internal or private, or maybe
    // create different versions of the function for different OMP internal
    // variables.
    Elem.second = new GlobalVariable(
        M, Ty, /*IsConstant=*/false, GlobalValue::CommonLinkage,
        Constant::getNullValue(Ty), Elem.first(),
        /*InsertBefore=*/nullptr, GlobalValue::NotThreadLocal, AddressSpace);
  }
 
  return cast<GlobalVariable>(&*Elem.second);
}
 
Value *OpenMPIRBuilder::getOMPCriticalRegionLock(StringRef CriticalName) {
  std::string Prefix = Twine("gomp_critical_user_", CriticalName).str();
  std::string Name = getNameWithSeparators({Prefix, "var"}, ".", ".");
  return getOrCreateInternalVariable(KmpCriticalNameTy, Name);
}
 
Value *OpenMPIRBuilder::getSizeInBytes(Value *BasePtr) {
  LLVMContext &Ctx = Builder.getContext();
  Value *Null = Constant::getNullValue(BasePtr->getType()->getPointerTo());
  Value *SizeGep =
      Builder.CreateGEP(BasePtr->getType(), Null, Builder.getInt32(1));
  Value *SizePtrToInt = Builder.CreatePtrToInt(SizeGep, Type::getInt64Ty(Ctx));
  return SizePtrToInt;
}
 
GlobalVariable *
OpenMPIRBuilder::createOffloadMaptypes(SmallVectorImpl<uint64_t> &Mappings,
                                       std::string VarName) {
  llvm::Constant *MaptypesArrayInit =
      llvm::ConstantDataArray::get(M.getContext(), Mappings);
  auto *MaptypesArrayGlobal = new llvm::GlobalVariable(
      M, MaptypesArrayInit->getType(),
      /*isConstant=*/true, llvm::GlobalValue::PrivateLinkage, MaptypesArrayInit,
      VarName);
  MaptypesArrayGlobal->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
  return MaptypesArrayGlobal;
}
 
void OpenMPIRBuilder::createMapperAllocas(const LocationDescription &Loc,
                                          InsertPointTy AllocaIP,
                                          unsigned NumOperands,
                                          struct MapperAllocas &MapperAllocas) {
  if (!updateToLocation(Loc))
    return;
 
  auto *ArrI8PtrTy = ArrayType::get(Int8Ptr, NumOperands);
  auto *ArrI64Ty = ArrayType::get(Int64, NumOperands);
  Builder.restoreIP(AllocaIP);
  AllocaInst *ArgsBase = Builder.CreateAlloca(
      ArrI8PtrTy, /* ArraySize = */ nullptr, ".offload_baseptrs");
  AllocaInst *Args = Builder.CreateAlloca(ArrI8PtrTy, /* ArraySize = */ nullptr,
                                          ".offload_ptrs");
  AllocaInst *ArgSizes = Builder.CreateAlloca(
      ArrI64Ty, /* ArraySize = */ nullptr, ".offload_sizes");
  Builder.restoreIP(Loc.IP);
  MapperAllocas.ArgsBase = ArgsBase;
  MapperAllocas.Args = Args;
  MapperAllocas.ArgSizes = ArgSizes;
}
 
void OpenMPIRBuilder::emitMapperCall(const LocationDescription &Loc,
                                     Function *MapperFunc, Value *SrcLocInfo,
                                     Value *MaptypesArg, Value *MapnamesArg,
                                     struct MapperAllocas &MapperAllocas,
                                     int64_t DeviceID, unsigned NumOperands) {
  if (!updateToLocation(Loc))
    return;
 
  auto *ArrI8PtrTy = ArrayType::get(Int8Ptr, NumOperands);
  auto *ArrI64Ty = ArrayType::get(Int64, NumOperands);
  Value *ArgsBaseGEP =
      Builder.CreateInBoundsGEP(ArrI8PtrTy, MapperAllocas.ArgsBase,
                                {Builder.getInt32(0), Builder.getInt32(0)});
  Value *ArgsGEP =
      Builder.CreateInBoundsGEP(ArrI8PtrTy, MapperAllocas.Args,
                                {Builder.getInt32(0), Builder.getInt32(0)});
  Value *ArgSizesGEP =
      Builder.CreateInBoundsGEP(ArrI64Ty, MapperAllocas.ArgSizes,
                                {Builder.getInt32(0), Builder.getInt32(0)});
  Value *NullPtr = Constant::getNullValue(Int8Ptr->getPointerTo());
  Builder.CreateCall(MapperFunc,
                     {SrcLocInfo, Builder.getInt64(DeviceID),
                      Builder.getInt32(NumOperands), ArgsBaseGEP, ArgsGEP,
                      ArgSizesGEP, MaptypesArg, MapnamesArg, NullPtr});
}
 
void OpenMPIRBuilder::emitOffloadingArraysArgument(IRBuilderBase &Builder,
                                                   TargetDataRTArgs &RTArgs,
                                                   TargetDataInfo &Info,
                                                   bool EmitDebug,
                                                   bool ForEndCall) {
  assert((!ForEndCall || Info.separateBeginEndCalls()) &&
         "expected region end call to runtime only when end call is separate");
  auto VoidPtrTy = Type::getInt8PtrTy(M.getContext());
  auto VoidPtrPtrTy = VoidPtrTy->getPointerTo(0);
  auto Int64Ty = Type::getInt64Ty(M.getContext());
  auto Int64PtrTy = Type::getInt64PtrTy(M.getContext());
 
  if (!Info.NumberOfPtrs) {
    RTArgs.BasePointersArray = ConstantPointerNull::get(VoidPtrPtrTy);
    RTArgs.PointersArray = ConstantPointerNull::get(VoidPtrPtrTy);
    RTArgs.SizesArray = ConstantPointerNull::get(Int64PtrTy);
    RTArgs.MapTypesArray = ConstantPointerNull::get(Int64PtrTy);
    RTArgs.MapNamesArray = ConstantPointerNull::get(VoidPtrPtrTy);
    RTArgs.MappersArray = ConstantPointerNull::get(VoidPtrPtrTy);
    return;
  }
 
  RTArgs.BasePointersArray = Builder.CreateConstInBoundsGEP2_32(
      ArrayType::get(VoidPtrTy, Info.NumberOfPtrs),
      Info.RTArgs.BasePointersArray,
      /*Idx0=*/0, /*Idx1=*/0);
  RTArgs.PointersArray = Builder.CreateConstInBoundsGEP2_32(
      ArrayType::get(VoidPtrTy, Info.NumberOfPtrs), Info.RTArgs.PointersArray,
      /*Idx0=*/0,
      /*Idx1=*/0);
  RTArgs.SizesArray = Builder.CreateConstInBoundsGEP2_32(
      ArrayType::get(Int64Ty, Info.NumberOfPtrs), Info.RTArgs.SizesArray,
      /*Idx0=*/0, /*Idx1=*/0);
  RTArgs.MapTypesArray = Builder.CreateConstInBoundsGEP2_32(
      ArrayType::get(Int64Ty, Info.NumberOfPtrs),
      ForEndCall && Info.RTArgs.MapTypesArrayEnd ? Info.RTArgs.MapTypesArrayEnd
                                                 : Info.RTArgs.MapTypesArray,
      /*Idx0=*/0,
      /*Idx1=*/0);
 
  // Only emit the mapper information arrays if debug information is
  // requested.
  if (!EmitDebug)
    RTArgs.MapNamesArray = ConstantPointerNull::get(VoidPtrPtrTy);
  else
    RTArgs.MapNamesArray = Builder.CreateConstInBoundsGEP2_32(
        ArrayType::get(VoidPtrTy, Info.NumberOfPtrs), Info.RTArgs.MapNamesArray,
        /*Idx0=*/0,
        /*Idx1=*/0);
  // If there is no user-defined mapper, set the mapper array to nullptr to
  // avoid an unnecessary data privatization
  if (!Info.HasMapper)
    RTArgs.MappersArray = ConstantPointerNull::get(VoidPtrPtrTy);
  else
    RTArgs.MappersArray =
        Builder.CreatePointerCast(Info.RTArgs.MappersArray, VoidPtrPtrTy);
}
 
bool OpenMPIRBuilder::checkAndEmitFlushAfterAtomic(
    const LocationDescription &Loc, llvm::AtomicOrdering AO, AtomicKind AK) {
  assert(!(AO == AtomicOrdering::NotAtomic ||
           AO == llvm::AtomicOrdering::Unordered) &&
         "Unexpected Atomic Ordering.");
 
  bool Flush = false;
  llvm::AtomicOrdering FlushAO = AtomicOrdering::Monotonic;
 
  switch (AK) {
  case Read:
    if (AO == AtomicOrdering::Acquire || AO == AtomicOrdering::AcquireRelease ||
        AO == AtomicOrdering::SequentiallyConsistent) {
      FlushAO = AtomicOrdering::Acquire;
      Flush = true;
    }
    break;
  case Write:
  case Compare:
  case Update:
    if (AO == AtomicOrdering::Release || AO == AtomicOrdering::AcquireRelease ||
        AO == AtomicOrdering::SequentiallyConsistent) {
      FlushAO = AtomicOrdering::Release;
      Flush = true;
    }
    break;
  case Capture:
    switch (AO) {
    case AtomicOrdering::Acquire:
      FlushAO = AtomicOrdering::Acquire;
      Flush = true;
      break;
    case AtomicOrdering::Release:
      FlushAO = AtomicOrdering::Release;
      Flush = true;
      break;
    case AtomicOrdering::AcquireRelease:
    case AtomicOrdering::SequentiallyConsistent:
      FlushAO = AtomicOrdering::AcquireRelease;
      Flush = true;
      break;
    default:
      // do nothing - leave silently.
      break;
    }
  }
 
  if (Flush) {
    // Currently Flush RT call still doesn't take memory_ordering, so for when
    // that happens, this tries to do the resolution of which atomic ordering
    // to use with but issue the flush call
    // TODO: pass `FlushAO` after memory ordering support is added
    (void)FlushAO;
    emitFlush(Loc);
  }
 
  // for AO == AtomicOrdering::Monotonic and  all other case combinations
  // do nothing
  return Flush;
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createAtomicRead(const LocationDescription &Loc,
                                  AtomicOpValue &X, AtomicOpValue &V,
                                  AtomicOrdering AO) {
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  Type *XTy = X.Var->getType();
  assert(XTy->isPointerTy() && "OMP Atomic expects a pointer to target memory");
  Type *XElemTy = X.ElemTy;
  assert((XElemTy->isFloatingPointTy() || XElemTy->isIntegerTy() ||
          XElemTy->isPointerTy()) &&
         "OMP atomic read expected a scalar type");
 
  Value *XRead = nullptr;
 
  if (XElemTy->isIntegerTy()) {
    LoadInst *XLD =
        Builder.CreateLoad(XElemTy, X.Var, X.IsVolatile, "omp.atomic.read");
    XLD->setAtomic(AO);
    XRead = cast<Value>(XLD);
  } else {
    // We need to bitcast and perform atomic op as integer
    unsigned Addrspace = cast<PointerType>(XTy)->getAddressSpace();
    IntegerType *IntCastTy =
        IntegerType::get(M.getContext(), XElemTy->getScalarSizeInBits());
    Value *XBCast = Builder.CreateBitCast(
        X.Var, IntCastTy->getPointerTo(Addrspace), "atomic.src.int.cast");
    LoadInst *XLoad =
        Builder.CreateLoad(IntCastTy, XBCast, X.IsVolatile, "omp.atomic.load");
    XLoad->setAtomic(AO);
    if (XElemTy->isFloatingPointTy()) {
      XRead = Builder.CreateBitCast(XLoad, XElemTy, "atomic.flt.cast");
    } else {
      XRead = Builder.CreateIntToPtr(XLoad, XElemTy, "atomic.ptr.cast");
    }
  }
  checkAndEmitFlushAfterAtomic(Loc, AO, AtomicKind::Read);
  Builder.CreateStore(XRead, V.Var, V.IsVolatile);
  return Builder.saveIP();
}
 
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::createAtomicWrite(const LocationDescription &Loc,
                                   AtomicOpValue &X, Value *Expr,
                                   AtomicOrdering AO) {
  if (!updateToLocation(Loc))
    return Loc.IP;
 
  Type *XTy = X.Var->getType();
  assert(XTy->isPointerTy() && "OMP Atomic expects a pointer to target memory");
  Type *XElemTy = X.ElemTy;
  assert((XElemTy->