| //===--- BlockGenerators.cpp - Generate code for statements -----*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the BlockGenerator and VectorBlockGenerator classes, |
| // which generate sequential code and vectorized code for a polyhedral |
| // statement, respectively. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "polly/ScopInfo.h" |
| #include "polly/CodeGen/BlockGenerators.h" |
| #include "polly/CodeGen/CodeGeneration.h" |
| #include "polly/CodeGen/IslExprBuilder.h" |
| #include "polly/Options.h" |
| #include "polly/Support/GICHelper.h" |
| #include "polly/Support/SCEVValidator.h" |
| #include "polly/Support/ScopHelper.h" |
| #include "llvm/Analysis/LoopInfo.h" |
| #include "llvm/Analysis/RegionInfo.h" |
| #include "llvm/Analysis/ScalarEvolution.h" |
| #include "llvm/Analysis/ScalarEvolutionExpander.h" |
| #include "llvm/IR/IntrinsicInst.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/Transforms/Utils/BasicBlockUtils.h" |
| #include "isl/aff.h" |
| #include "isl/ast.h" |
| #include "isl/ast_build.h" |
| #include "isl/set.h" |
| #include <deque> |
| |
| using namespace llvm; |
| using namespace polly; |
| |
| static cl::opt<bool> Aligned("enable-polly-aligned", |
| cl::desc("Assumed aligned memory accesses."), |
| cl::Hidden, cl::init(false), cl::ZeroOrMore, |
| cl::cat(PollyCategory)); |
| |
| bool polly::canSynthesize(const Instruction *I, const llvm::LoopInfo *LI, |
| ScalarEvolution *SE, const Region *R) { |
| if (!I || !SE->isSCEVable(I->getType())) |
| return false; |
| |
| if (const SCEV *Scev = SE->getSCEV(const_cast<Instruction *>(I))) |
| if (!isa<SCEVCouldNotCompute>(Scev)) |
| if (!hasScalarDepsInsideRegion(Scev, R)) |
| return true; |
| |
| return false; |
| } |
| |
| bool polly::isIgnoredIntrinsic(const Value *V) { |
| if (auto *IT = dyn_cast<IntrinsicInst>(V)) { |
| switch (IT->getIntrinsicID()) { |
| // Lifetime markers are supported/ignored. |
| case llvm::Intrinsic::lifetime_start: |
| case llvm::Intrinsic::lifetime_end: |
| // Invariant markers are supported/ignored. |
| case llvm::Intrinsic::invariant_start: |
| case llvm::Intrinsic::invariant_end: |
| // Some misc annotations are supported/ignored. |
| case llvm::Intrinsic::var_annotation: |
| case llvm::Intrinsic::ptr_annotation: |
| case llvm::Intrinsic::annotation: |
| case llvm::Intrinsic::donothing: |
| case llvm::Intrinsic::assume: |
| case llvm::Intrinsic::expect: |
| return true; |
| default: |
| break; |
| } |
| } |
| return false; |
| } |
| |
| BlockGenerator::BlockGenerator(PollyIRBuilder &B, LoopInfo &LI, |
| ScalarEvolution &SE, DominatorTree &DT, |
| ScalarAllocaMapTy &ScalarMap, |
| ScalarAllocaMapTy &PHIOpMap, |
| EscapeUsersAllocaMapTy &EscapeMap, |
| IslExprBuilder *ExprBuilder) |
| : Builder(B), LI(LI), SE(SE), ExprBuilder(ExprBuilder), DT(DT), |
| EntryBB(nullptr), PHIOpMap(PHIOpMap), ScalarMap(ScalarMap), |
| EscapeMap(EscapeMap) {} |
| |
| Value *BlockGenerator::getNewValue(ScopStmt &Stmt, const Value *Old, |
| ValueMapT &BBMap, ValueMapT &GlobalMap, |
| LoopToScevMapT <S, Loop *L) const { |
| // We assume constants never change. |
| // This avoids map lookups for many calls to this function. |
| if (isa<Constant>(Old)) |
| return const_cast<Value *>(Old); |
| |
| if (Value *New = GlobalMap.lookup(Old)) { |
| if (Old->getType()->getScalarSizeInBits() < |
| New->getType()->getScalarSizeInBits()) |
| New = Builder.CreateTruncOrBitCast(New, Old->getType()); |
| |
| return New; |
| } |
| |
| if (Value *New = BBMap.lookup(Old)) |
| return New; |
| |
| if (SE.isSCEVable(Old->getType())) |
| if (const SCEV *Scev = SE.getSCEVAtScope(const_cast<Value *>(Old), L)) { |
| if (!isa<SCEVCouldNotCompute>(Scev)) { |
| const SCEV *NewScev = apply(Scev, LTS, SE); |
| ValueToValueMap VTV; |
| VTV.insert(BBMap.begin(), BBMap.end()); |
| VTV.insert(GlobalMap.begin(), GlobalMap.end()); |
| NewScev = SCEVParameterRewriter::rewrite(NewScev, SE, VTV); |
| SCEVExpander Expander(SE, Stmt.getParent() |
| ->getRegion() |
| .getEntry() |
| ->getParent() |
| ->getParent() |
| ->getDataLayout(), |
| "polly"); |
| assert(Builder.GetInsertPoint() != Builder.GetInsertBlock()->end() && |
| "Only instructions can be insert points for SCEVExpander"); |
| Value *Expanded = Expander.expandCodeFor(NewScev, Old->getType(), |
| Builder.GetInsertPoint()); |
| |
| BBMap[Old] = Expanded; |
| return Expanded; |
| } |
| } |
| |
| // A scop-constant value defined by a global or a function parameter. |
| if (isa<GlobalValue>(Old) || isa<Argument>(Old)) |
| return const_cast<Value *>(Old); |
| |
| // A scop-constant value defined by an instruction executed outside the scop. |
| if (const Instruction *Inst = dyn_cast<Instruction>(Old)) |
| if (!Stmt.getParent()->getRegion().contains(Inst->getParent())) |
| return const_cast<Value *>(Old); |
| |
| // The scalar dependence is neither available nor SCEVCodegenable. |
| llvm_unreachable("Unexpected scalar dependence in region!"); |
| return nullptr; |
| } |
| |
| void BlockGenerator::copyInstScalar(ScopStmt &Stmt, const Instruction *Inst, |
| ValueMapT &BBMap, ValueMapT &GlobalMap, |
| LoopToScevMapT <S) { |
| // We do not generate debug intrinsics as we did not investigate how to |
| // copy them correctly. At the current state, they just crash the code |
| // generation as the meta-data operands are not correctly copied. |
| if (isa<DbgInfoIntrinsic>(Inst)) |
| return; |
| |
| Instruction *NewInst = Inst->clone(); |
| |
| // Replace old operands with the new ones. |
| for (Value *OldOperand : Inst->operands()) { |
| Value *NewOperand = getNewValue(Stmt, OldOperand, BBMap, GlobalMap, LTS, |
| getLoopForInst(Inst)); |
| |
| if (!NewOperand) { |
| assert(!isa<StoreInst>(NewInst) && |
| "Store instructions are always needed!"); |
| delete NewInst; |
| return; |
| } |
| |
| NewInst->replaceUsesOfWith(OldOperand, NewOperand); |
| } |
| |
| Builder.Insert(NewInst); |
| BBMap[Inst] = NewInst; |
| |
| if (!NewInst->getType()->isVoidTy()) |
| NewInst->setName("p_" + Inst->getName()); |
| } |
| |
| Value *BlockGenerator::getNewAccessOperand(ScopStmt &Stmt, |
| const MemoryAccess &MA) { |
| isl_pw_multi_aff *PWAccRel; |
| isl_union_map *Schedule; |
| isl_ast_expr *Expr; |
| isl_ast_build *Build = Stmt.getAstBuild(); |
| |
| assert(ExprBuilder && Build && |
| "Cannot generate new value without IslExprBuilder!"); |
| |
| Schedule = isl_ast_build_get_schedule(Build); |
| PWAccRel = MA.applyScheduleToAccessRelation(Schedule); |
| |
| Expr = isl_ast_build_access_from_pw_multi_aff(Build, PWAccRel); |
| Expr = isl_ast_expr_address_of(Expr); |
| |
| return ExprBuilder->create(Expr); |
| } |
| |
| Value *BlockGenerator::generateLocationAccessed( |
| ScopStmt &Stmt, const Instruction *Inst, const Value *Pointer, |
| ValueMapT &BBMap, ValueMapT &GlobalMap, LoopToScevMapT <S) { |
| const MemoryAccess &MA = Stmt.getAccessFor(Inst); |
| |
| Value *NewPointer; |
| if (MA.hasNewAccessRelation()) |
| NewPointer = getNewAccessOperand(Stmt, MA); |
| else |
| NewPointer = |
| getNewValue(Stmt, Pointer, BBMap, GlobalMap, LTS, getLoopForInst(Inst)); |
| |
| return NewPointer; |
| } |
| |
| Loop *BlockGenerator::getLoopForInst(const llvm::Instruction *Inst) { |
| return LI.getLoopFor(Inst->getParent()); |
| } |
| |
| Value *BlockGenerator::generateScalarLoad(ScopStmt &Stmt, const LoadInst *Load, |
| ValueMapT &BBMap, |
| ValueMapT &GlobalMap, |
| LoopToScevMapT <S) { |
| const Value *Pointer = Load->getPointerOperand(); |
| Value *NewPointer = |
| generateLocationAccessed(Stmt, Load, Pointer, BBMap, GlobalMap, LTS); |
| Value *ScalarLoad = Builder.CreateAlignedLoad( |
| NewPointer, Load->getAlignment(), Load->getName() + "_p_scalar_"); |
| return ScalarLoad; |
| } |
| |
| Value *BlockGenerator::generateScalarStore(ScopStmt &Stmt, |
| const StoreInst *Store, |
| ValueMapT &BBMap, |
| ValueMapT &GlobalMap, |
| LoopToScevMapT <S) { |
| const Value *Pointer = Store->getPointerOperand(); |
| Value *NewPointer = |
| generateLocationAccessed(Stmt, Store, Pointer, BBMap, GlobalMap, LTS); |
| Value *ValueOperand = getNewValue(Stmt, Store->getValueOperand(), BBMap, |
| GlobalMap, LTS, getLoopForInst(Store)); |
| |
| Value *NewStore = Builder.CreateAlignedStore(ValueOperand, NewPointer, |
| Store->getAlignment()); |
| return NewStore; |
| } |
| |
| void BlockGenerator::copyInstruction(ScopStmt &Stmt, const Instruction *Inst, |
| ValueMapT &BBMap, ValueMapT &GlobalMap, |
| LoopToScevMapT <S) { |
| |
| // First check for possible scalar dependences for this instruction. |
| generateScalarLoads(Stmt, Inst, BBMap); |
| |
| // Terminator instructions control the control flow. They are explicitly |
| // expressed in the clast and do not need to be copied. |
| if (Inst->isTerminator()) |
| return; |
| |
| Loop *L = getLoopForInst(Inst); |
| if ((Stmt.isBlockStmt() || !Stmt.getRegion()->contains(L)) && |
| canSynthesize(Inst, &LI, &SE, &Stmt.getParent()->getRegion())) { |
| Value *NewValue = getNewValue(Stmt, Inst, BBMap, GlobalMap, LTS, L); |
| BBMap[Inst] = NewValue; |
| return; |
| } |
| |
| if (const LoadInst *Load = dyn_cast<LoadInst>(Inst)) { |
| Value *NewLoad = generateScalarLoad(Stmt, Load, BBMap, GlobalMap, LTS); |
| // Compute NewLoad before its insertion in BBMap to make the insertion |
| // deterministic. |
| BBMap[Load] = NewLoad; |
| return; |
| } |
| |
| if (const StoreInst *Store = dyn_cast<StoreInst>(Inst)) { |
| Value *NewStore = generateScalarStore(Stmt, Store, BBMap, GlobalMap, LTS); |
| // Compute NewStore before its insertion in BBMap to make the insertion |
| // deterministic. |
| BBMap[Store] = NewStore; |
| return; |
| } |
| |
| if (const PHINode *PHI = dyn_cast<PHINode>(Inst)) { |
| copyPHIInstruction(Stmt, PHI, BBMap, GlobalMap, LTS); |
| return; |
| } |
| |
| // Skip some special intrinsics for which we do not adjust the semantics to |
| // the new schedule. All others are handled like every other instruction. |
| if (auto *IT = dyn_cast<IntrinsicInst>(Inst)) { |
| switch (IT->getIntrinsicID()) { |
| // Lifetime markers are ignored. |
| case llvm::Intrinsic::lifetime_start: |
| case llvm::Intrinsic::lifetime_end: |
| // Invariant markers are ignored. |
| case llvm::Intrinsic::invariant_start: |
| case llvm::Intrinsic::invariant_end: |
| // Some misc annotations are ignored. |
| case llvm::Intrinsic::var_annotation: |
| case llvm::Intrinsic::ptr_annotation: |
| case llvm::Intrinsic::annotation: |
| case llvm::Intrinsic::donothing: |
| case llvm::Intrinsic::assume: |
| case llvm::Intrinsic::expect: |
| return; |
| default: |
| // Other intrinsics are copied. |
| break; |
| } |
| } |
| |
| copyInstScalar(Stmt, Inst, BBMap, GlobalMap, LTS); |
| } |
| |
| void BlockGenerator::copyStmt(ScopStmt &Stmt, ValueMapT &GlobalMap, |
| LoopToScevMapT <S) { |
| assert(Stmt.isBlockStmt() && |
| "Only block statements can be copied by the block generator"); |
| |
| ValueMapT BBMap; |
| |
| BasicBlock *BB = Stmt.getBasicBlock(); |
| copyBB(Stmt, BB, BBMap, GlobalMap, LTS); |
| } |
| |
| BasicBlock *BlockGenerator::splitBB(BasicBlock *BB) { |
| BasicBlock *CopyBB = |
| SplitBlock(Builder.GetInsertBlock(), Builder.GetInsertPoint(), &DT, &LI); |
| CopyBB->setName("polly.stmt." + BB->getName()); |
| return CopyBB; |
| } |
| |
| BasicBlock *BlockGenerator::copyBB(ScopStmt &Stmt, BasicBlock *BB, |
| ValueMapT &BBMap, ValueMapT &GlobalMap, |
| LoopToScevMapT <S) { |
| BasicBlock *CopyBB = splitBB(BB); |
| copyBB(Stmt, BB, CopyBB, BBMap, GlobalMap, LTS); |
| return CopyBB; |
| } |
| |
| void BlockGenerator::copyBB(ScopStmt &Stmt, BasicBlock *BB, BasicBlock *CopyBB, |
| ValueMapT &BBMap, ValueMapT &GlobalMap, |
| LoopToScevMapT <S) { |
| Builder.SetInsertPoint(CopyBB->begin()); |
| EntryBB = &CopyBB->getParent()->getEntryBlock(); |
| |
| for (Instruction &Inst : *BB) |
| copyInstruction(Stmt, &Inst, BBMap, GlobalMap, LTS); |
| |
| // After a basic block was copied store all scalars that escape this block |
| // in their alloca. First the scalars that have dependences inside the SCoP, |
| // then the ones that might escape the SCoP. |
| generateScalarStores(Stmt, BB, BBMap, GlobalMap); |
| |
| const Region &R = Stmt.getParent()->getRegion(); |
| for (Instruction &Inst : *BB) |
| handleOutsideUsers(R, &Inst, BBMap[&Inst]); |
| } |
| |
| AllocaInst *BlockGenerator::getOrCreateAlloca(Instruction *ScalarBase, |
| ScalarAllocaMapTy &Map, |
| const char *NameExt, |
| bool *IsNew) { |
| |
| // Check if an alloca was cached for the base instruction. |
| AllocaInst *&Addr = Map[ScalarBase]; |
| |
| // If needed indicate if it was found already or will be created. |
| if (IsNew) |
| *IsNew = (Addr == nullptr); |
| |
| // If no alloca was found create one and insert it in the entry block. |
| if (!Addr) { |
| auto *Ty = ScalarBase->getType(); |
| Addr = new AllocaInst(Ty, ScalarBase->getName() + NameExt); |
| Addr->insertBefore(EntryBB->getFirstInsertionPt()); |
| } |
| |
| return Addr; |
| } |
| |
| void BlockGenerator::handleOutsideUsers(const Region &R, Instruction *Inst, |
| Value *InstCopy) { |
| BasicBlock *ExitBB = R.getExit(); |
| |
| EscapeUserVectorTy EscapeUsers; |
| for (User *U : Inst->users()) { |
| |
| // Non-instruction user will never escape. |
| Instruction *UI = dyn_cast<Instruction>(U); |
| if (!UI) |
| continue; |
| |
| if (R.contains(UI) && ExitBB != UI->getParent()) |
| continue; |
| |
| EscapeUsers.push_back(UI); |
| } |
| |
| // Exit if no escape uses were found. |
| if (EscapeUsers.empty()) |
| return; |
| |
| // If there are escape users we get the alloca for this instruction and put |
| // it in the EscapeMap for later finalization. However, if the alloca was not |
| // created by an already handled scalar dependence we have to initialize it |
| // also. Lastly, if the instruction was copied multiple times we already did |
| // this and can exit. |
| if (EscapeMap.count(Inst)) |
| return; |
| |
| // Get or create an escape alloca for this instruction. |
| bool IsNew; |
| AllocaInst *ScalarAddr = |
| getOrCreateAlloca(Inst, ScalarMap, ".escape", &IsNew); |
| |
| // Remember that this instruction has escape uses and the escape alloca. |
| EscapeMap[Inst] = std::make_pair(ScalarAddr, std::move(EscapeUsers)); |
| |
| // If the escape alloca was just created store the instruction in there, |
| // otherwise that happened already. |
| if (IsNew) { |
| assert(InstCopy && "Except PHIs every instruction should have a copy!"); |
| Builder.CreateStore(InstCopy, ScalarAddr); |
| } |
| } |
| |
| void BlockGenerator::generateScalarLoads(ScopStmt &Stmt, |
| const Instruction *Inst, |
| ValueMapT &BBMap) { |
| |
| // Iterate over all memory accesses for the given instruction and handle all |
| // scalar reads. |
| if (ScopStmt::MemoryAccessList *MAL = Stmt.lookupAccessesFor(Inst)) { |
| for (MemoryAccess &MA : *MAL) { |
| if (!MA.isScalar() || !MA.isRead()) |
| continue; |
| |
| Instruction *ScalarBase = cast<Instruction>(MA.getBaseAddr()); |
| Instruction *ScalarInst = MA.getAccessInstruction(); |
| |
| PHINode *ScalarBasePHI = dyn_cast<PHINode>(ScalarBase); |
| |
| // This is either a common scalar use (second case) or the use of a phi |
| // operand by the PHI node (first case). |
| if (ScalarBasePHI == ScalarInst) { |
| AllocaInst *PHIOpAddr = |
| getOrCreateAlloca(ScalarBase, PHIOpMap, ".phiops"); |
| LoadInst *LI = |
| Builder.CreateLoad(PHIOpAddr, PHIOpAddr->getName() + ".reload"); |
| BBMap[ScalarBase] = LI; |
| } else { |
| // For non-PHI operand uses we look up the alloca in the ScalarMap, |
| // reload it and add the mapping to the ones in the current basic block. |
| AllocaInst *ScalarAddr = |
| getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a"); |
| LoadInst *LI = |
| Builder.CreateLoad(ScalarAddr, ScalarAddr->getName() + ".reload"); |
| BBMap[ScalarBase] = LI; |
| } |
| } |
| } |
| } |
| |
| Value *BlockGenerator::getNewScalarValue(Value *ScalarValue, const Region &R, |
| ScalarAllocaMapTy &ReloadMap, |
| ValueMapT &BBMap, |
| ValueMapT &GlobalMap) { |
| // If the value we want to store is an instruction we might have demoted it |
| // in order to make it accessible here. In such a case a reload is |
| // necessary. If it is no instruction it will always be a value that |
| // dominates the current point and we can just use it. In total there are 4 |
| // options: |
| // (1) The value is no instruction ==> use the value. |
| // (2) The value is an instruction that was split out of the region prior to |
| // code generation ==> use the instruction as it dominates the region. |
| // (3) The value is an instruction: |
| // (a) The value was defined in the current block, thus a copy is in |
| // the BBMap ==> use the mapped value. |
| // (b) The value was defined in a previous block, thus we demoted it |
| // earlier ==> use the reloaded value. |
| Instruction *ScalarValueInst = dyn_cast<Instruction>(ScalarValue); |
| if (!ScalarValueInst) |
| return ScalarValue; |
| |
| if (!R.contains(ScalarValueInst)) { |
| if (Value *ScalarValueCopy = GlobalMap.lookup(ScalarValueInst)) |
| return /* Case (3a) */ ScalarValueCopy; |
| else |
| return /* Case 2 */ ScalarValue; |
| } |
| |
| if (Value *ScalarValueCopy = BBMap.lookup(ScalarValueInst)) |
| return /* Case (3a) */ ScalarValueCopy; |
| |
| // Case (3b) |
| assert(ReloadMap.count(ScalarValueInst) && |
| "ScalarInst not mapped in the block and not in the given reload map!"); |
| Value *ReloadAddr = ReloadMap[ScalarValueInst]; |
| ScalarValue = |
| Builder.CreateLoad(ReloadAddr, ReloadAddr->getName() + ".reload"); |
| |
| return ScalarValue; |
| } |
| |
| void BlockGenerator::generateScalarStores(ScopStmt &Stmt, BasicBlock *BB, |
| ValueMapT &BBMap, |
| ValueMapT &GlobalMap) { |
| const Region &R = Stmt.getParent()->getRegion(); |
| |
| assert(Stmt.isBlockStmt() && BB == Stmt.getBasicBlock() && |
| "Region statements need to use the generateScalarStores() " |
| "function in the RegionGenerator"); |
| |
| // Set to remember a store to the phiops alloca of a PHINode. It is needed as |
| // we might have multiple write accesses to the same PHI and while one is the |
| // self write of the PHI (to the ScalarMap alloca) the other is the write to |
| // the operand alloca (PHIOpMap). |
| SmallPtrSet<PHINode *, 4> SeenPHIs; |
| |
| // Iterate over all accesses in the given statement. |
| for (MemoryAccess *MA : Stmt) { |
| |
| // Skip non-scalar and read accesses. |
| if (!MA->isScalar() || MA->isRead()) |
| continue; |
| |
| Instruction *ScalarBase = cast<Instruction>(MA->getBaseAddr()); |
| Instruction *ScalarInst = MA->getAccessInstruction(); |
| PHINode *ScalarBasePHI = dyn_cast<PHINode>(ScalarBase); |
| |
| // Get the alloca node for the base instruction and the value we want to |
| // store. In total there are 4 options: |
| // (1) The base is no PHI, hence it is a simple scalar def-use chain. |
| // (2) The base is a PHI, |
| // (a) and the write is caused by an operand in the block. |
| // (b) and it is the PHI self write (same as case (1)). |
| // (c) (2a) and (2b) are not distinguishable. |
| // For case (1) and (2b) we get the alloca from the scalar map and the value |
| // we want to store is initialized with the instruction attached to the |
| // memory access. For case (2a) we get the alloca from the PHI operand map |
| // and the value we want to store is initialized with the incoming value for |
| // this block. The tricky case (2c) is when both (2a) and (2b) match. This |
| // happens if the PHI operand is in the same block as the PHI. To handle |
| // that we choose the alloca of (2a) first and (2b) for the next write |
| // access to that PHI (there must be 2). |
| Value *ScalarValue = nullptr; |
| AllocaInst *ScalarAddr = nullptr; |
| |
| if (!ScalarBasePHI) { |
| // Case (1) |
| ScalarAddr = getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a"); |
| ScalarValue = ScalarInst; |
| } else { |
| int PHIIdx = ScalarBasePHI->getBasicBlockIndex(BB); |
| if (ScalarBasePHI != ScalarInst) { |
| // Case (2a) |
| assert(PHIIdx >= 0 && "Bad scalar write to PHI operand"); |
| SeenPHIs.insert(ScalarBasePHI); |
| ScalarAddr = getOrCreateAlloca(ScalarBase, PHIOpMap, ".phiops"); |
| ScalarValue = ScalarBasePHI->getIncomingValue(PHIIdx); |
| } else if (PHIIdx < 0) { |
| // Case (2b) |
| ScalarAddr = getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a"); |
| ScalarValue = ScalarInst; |
| } else { |
| // Case (2c) |
| if (SeenPHIs.insert(ScalarBasePHI).second) { |
| // First access ==> same as (2a) |
| ScalarAddr = getOrCreateAlloca(ScalarBase, PHIOpMap, ".phiops"); |
| ScalarValue = ScalarBasePHI->getIncomingValue(PHIIdx); |
| } else { |
| // Second access ==> same as (2b) |
| ScalarAddr = getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a"); |
| ScalarValue = ScalarInst; |
| } |
| } |
| } |
| |
| ScalarValue = |
| getNewScalarValue(ScalarValue, R, ScalarMap, BBMap, GlobalMap); |
| Builder.CreateStore(ScalarValue, ScalarAddr); |
| } |
| } |
| |
| void BlockGenerator::createScalarInitialization(Region &R, |
| ValueMapT &GlobalMap) { |
| // The split block __just before__ the region and optimized region. |
| BasicBlock *SplitBB = R.getEnteringBlock(); |
| BranchInst *SplitBBTerm = cast<BranchInst>(SplitBB->getTerminator()); |
| assert(SplitBBTerm->getNumSuccessors() == 2 && "Bad region entering block!"); |
| |
| // Get the start block of the __optimized__ region. |
| BasicBlock *StartBB = SplitBBTerm->getSuccessor(0); |
| if (StartBB == R.getEntry()) |
| StartBB = SplitBBTerm->getSuccessor(1); |
| |
| // For each PHI predecessor outside the region store the incoming operand |
| // value prior to entering the optimized region. |
| Builder.SetInsertPoint(StartBB->getTerminator()); |
| |
| ScalarAllocaMapTy EmptyMap; |
| for (const auto &PHIOpMapping : PHIOpMap) { |
| const PHINode *PHI = cast<PHINode>(PHIOpMapping.getFirst()); |
| |
| // Check if this PHI has the split block as predecessor (that is the only |
| // possible predecessor outside the SCoP). |
| int idx = PHI->getBasicBlockIndex(SplitBB); |
| if (idx < 0) |
| continue; |
| |
| Value *ScalarValue = PHI->getIncomingValue(idx); |
| ScalarValue = |
| getNewScalarValue(ScalarValue, R, EmptyMap, GlobalMap, GlobalMap); |
| |
| // If the split block is the predecessor initialize the PHI operator alloca. |
| Builder.CreateStore(ScalarValue, PHIOpMapping.getSecond()); |
| } |
| } |
| |
| void BlockGenerator::createScalarFinalization(Region &R) { |
| // The exit block of the __unoptimized__ region. |
| BasicBlock *ExitBB = R.getExitingBlock(); |
| // The merge block __just after__ the region and the optimized region. |
| BasicBlock *MergeBB = R.getExit(); |
| |
| // The exit block of the __optimized__ region. |
| BasicBlock *OptExitBB = *(pred_begin(MergeBB)); |
| if (OptExitBB == ExitBB) |
| OptExitBB = *(++pred_begin(MergeBB)); |
| |
| Builder.SetInsertPoint(OptExitBB->getTerminator()); |
| for (const auto &EscapeMapping : EscapeMap) { |
| // Extract the escaping instruction and the escaping users as well as the |
| // alloca the instruction was demoted to. |
| Instruction *EscapeInst = EscapeMapping.getFirst(); |
| const auto &EscapeMappingValue = EscapeMapping.getSecond(); |
| const EscapeUserVectorTy &EscapeUsers = EscapeMappingValue.second; |
| AllocaInst *ScalarAddr = EscapeMappingValue.first; |
| |
| // Reload the demoted instruction in the optimized version of the SCoP. |
| Instruction *EscapeInstReload = |
| Builder.CreateLoad(ScalarAddr, EscapeInst->getName() + ".final_reload"); |
| |
| // Create the merge PHI that merges the optimized and unoptimized version. |
| PHINode *MergePHI = PHINode::Create(EscapeInst->getType(), 2, |
| EscapeInst->getName() + ".merge"); |
| MergePHI->insertBefore(MergeBB->getFirstInsertionPt()); |
| |
| // Add the respective values to the merge PHI. |
| MergePHI->addIncoming(EscapeInstReload, OptExitBB); |
| MergePHI->addIncoming(EscapeInst, ExitBB); |
| |
| // The information of scalar evolution about the escaping instruction needs |
| // to be revoked so the new merged instruction will be used. |
| if (SE.isSCEVable(EscapeInst->getType())) |
| SE.forgetValue(EscapeInst); |
| |
| // Replace all uses of the demoted instruction with the merge PHI. |
| for (Instruction *EUser : EscapeUsers) |
| EUser->replaceUsesOfWith(EscapeInst, MergePHI); |
| } |
| } |
| |
| void BlockGenerator::finalizeSCoP(Scop &S, ValueMapT &GlobalMap) { |
| createScalarInitialization(S.getRegion(), GlobalMap); |
| createScalarFinalization(S.getRegion()); |
| } |
| |
| VectorBlockGenerator::VectorBlockGenerator(BlockGenerator &BlockGen, |
| VectorValueMapT &GlobalMaps, |
| std::vector<LoopToScevMapT> &VLTS, |
| isl_map *Schedule) |
| : BlockGenerator(BlockGen), GlobalMaps(GlobalMaps), VLTS(VLTS), |
| Schedule(Schedule) { |
| assert(GlobalMaps.size() > 1 && "Only one vector lane found"); |
| assert(Schedule && "No statement domain provided"); |
| } |
| |
| Value *VectorBlockGenerator::getVectorValue(ScopStmt &Stmt, const Value *Old, |
| ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps, |
| Loop *L) { |
| if (Value *NewValue = VectorMap.lookup(Old)) |
| return NewValue; |
| |
| int Width = getVectorWidth(); |
| |
| Value *Vector = UndefValue::get(VectorType::get(Old->getType(), Width)); |
| |
| for (int Lane = 0; Lane < Width; Lane++) |
| Vector = Builder.CreateInsertElement( |
| Vector, getNewValue(Stmt, Old, ScalarMaps[Lane], GlobalMaps[Lane], |
| VLTS[Lane], L), |
| Builder.getInt32(Lane)); |
| |
| VectorMap[Old] = Vector; |
| |
| return Vector; |
| } |
| |
| Type *VectorBlockGenerator::getVectorPtrTy(const Value *Val, int Width) { |
| PointerType *PointerTy = dyn_cast<PointerType>(Val->getType()); |
| assert(PointerTy && "PointerType expected"); |
| |
| Type *ScalarType = PointerTy->getElementType(); |
| VectorType *VectorType = VectorType::get(ScalarType, Width); |
| |
| return PointerType::getUnqual(VectorType); |
| } |
| |
| Value *VectorBlockGenerator::generateStrideOneLoad( |
| ScopStmt &Stmt, const LoadInst *Load, VectorValueMapT &ScalarMaps, |
| bool NegativeStride = false) { |
| unsigned VectorWidth = getVectorWidth(); |
| const Value *Pointer = Load->getPointerOperand(); |
| Type *VectorPtrType = getVectorPtrTy(Pointer, VectorWidth); |
| unsigned Offset = NegativeStride ? VectorWidth - 1 : 0; |
| |
| Value *NewPointer = nullptr; |
| NewPointer = generateLocationAccessed(Stmt, Load, Pointer, ScalarMaps[Offset], |
| GlobalMaps[Offset], VLTS[Offset]); |
| Value *VectorPtr = |
| Builder.CreateBitCast(NewPointer, VectorPtrType, "vector_ptr"); |
| LoadInst *VecLoad = |
| Builder.CreateLoad(VectorPtr, Load->getName() + "_p_vec_full"); |
| if (!Aligned) |
| VecLoad->setAlignment(8); |
| |
| if (NegativeStride) { |
| SmallVector<Constant *, 16> Indices; |
| for (int i = VectorWidth - 1; i >= 0; i--) |
| Indices.push_back(ConstantInt::get(Builder.getInt32Ty(), i)); |
| Constant *SV = llvm::ConstantVector::get(Indices); |
| Value *RevVecLoad = Builder.CreateShuffleVector( |
| VecLoad, VecLoad, SV, Load->getName() + "_reverse"); |
| return RevVecLoad; |
| } |
| |
| return VecLoad; |
| } |
| |
| Value *VectorBlockGenerator::generateStrideZeroLoad(ScopStmt &Stmt, |
| const LoadInst *Load, |
| ValueMapT &BBMap) { |
| const Value *Pointer = Load->getPointerOperand(); |
| Type *VectorPtrType = getVectorPtrTy(Pointer, 1); |
| Value *NewPointer = generateLocationAccessed(Stmt, Load, Pointer, BBMap, |
| GlobalMaps[0], VLTS[0]); |
| Value *VectorPtr = Builder.CreateBitCast(NewPointer, VectorPtrType, |
| Load->getName() + "_p_vec_p"); |
| LoadInst *ScalarLoad = |
| Builder.CreateLoad(VectorPtr, Load->getName() + "_p_splat_one"); |
| |
| if (!Aligned) |
| ScalarLoad->setAlignment(8); |
| |
| Constant *SplatVector = Constant::getNullValue( |
| VectorType::get(Builder.getInt32Ty(), getVectorWidth())); |
| |
| Value *VectorLoad = Builder.CreateShuffleVector( |
| ScalarLoad, ScalarLoad, SplatVector, Load->getName() + "_p_splat"); |
| return VectorLoad; |
| } |
| |
| Value *VectorBlockGenerator::generateUnknownStrideLoad( |
| ScopStmt &Stmt, const LoadInst *Load, VectorValueMapT &ScalarMaps) { |
| int VectorWidth = getVectorWidth(); |
| const Value *Pointer = Load->getPointerOperand(); |
| VectorType *VectorType = VectorType::get( |
| dyn_cast<PointerType>(Pointer->getType())->getElementType(), VectorWidth); |
| |
| Value *Vector = UndefValue::get(VectorType); |
| |
| for (int i = 0; i < VectorWidth; i++) { |
| Value *NewPointer = generateLocationAccessed( |
| Stmt, Load, Pointer, ScalarMaps[i], GlobalMaps[i], VLTS[i]); |
| Value *ScalarLoad = |
| Builder.CreateLoad(NewPointer, Load->getName() + "_p_scalar_"); |
| Vector = Builder.CreateInsertElement( |
| Vector, ScalarLoad, Builder.getInt32(i), Load->getName() + "_p_vec_"); |
| } |
| |
| return Vector; |
| } |
| |
| void VectorBlockGenerator::generateLoad(ScopStmt &Stmt, const LoadInst *Load, |
| ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps) { |
| if (!VectorType::isValidElementType(Load->getType())) { |
| for (int i = 0; i < getVectorWidth(); i++) |
| ScalarMaps[i][Load] = |
| generateScalarLoad(Stmt, Load, ScalarMaps[i], GlobalMaps[i], VLTS[i]); |
| return; |
| } |
| |
| const MemoryAccess &Access = Stmt.getAccessFor(Load); |
| |
| // Make sure we have scalar values available to access the pointer to |
| // the data location. |
| extractScalarValues(Load, VectorMap, ScalarMaps); |
| |
| Value *NewLoad; |
| if (Access.isStrideZero(isl_map_copy(Schedule))) |
| NewLoad = generateStrideZeroLoad(Stmt, Load, ScalarMaps[0]); |
| else if (Access.isStrideOne(isl_map_copy(Schedule))) |
| NewLoad = generateStrideOneLoad(Stmt, Load, ScalarMaps); |
| else if (Access.isStrideX(isl_map_copy(Schedule), -1)) |
| NewLoad = generateStrideOneLoad(Stmt, Load, ScalarMaps, true); |
| else |
| NewLoad = generateUnknownStrideLoad(Stmt, Load, ScalarMaps); |
| |
| VectorMap[Load] = NewLoad; |
| } |
| |
| void VectorBlockGenerator::copyUnaryInst(ScopStmt &Stmt, |
| const UnaryInstruction *Inst, |
| ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps) { |
| int VectorWidth = getVectorWidth(); |
| Value *NewOperand = getVectorValue(Stmt, Inst->getOperand(0), VectorMap, |
| ScalarMaps, getLoopForInst(Inst)); |
| |
| assert(isa<CastInst>(Inst) && "Can not generate vector code for instruction"); |
| |
| const CastInst *Cast = dyn_cast<CastInst>(Inst); |
| VectorType *DestType = VectorType::get(Inst->getType(), VectorWidth); |
| VectorMap[Inst] = Builder.CreateCast(Cast->getOpcode(), NewOperand, DestType); |
| } |
| |
| void VectorBlockGenerator::copyBinaryInst(ScopStmt &Stmt, |
| const BinaryOperator *Inst, |
| ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps) { |
| Loop *L = getLoopForInst(Inst); |
| Value *OpZero = Inst->getOperand(0); |
| Value *OpOne = Inst->getOperand(1); |
| |
| Value *NewOpZero, *NewOpOne; |
| NewOpZero = getVectorValue(Stmt, OpZero, VectorMap, ScalarMaps, L); |
| NewOpOne = getVectorValue(Stmt, OpOne, VectorMap, ScalarMaps, L); |
| |
| Value *NewInst = Builder.CreateBinOp(Inst->getOpcode(), NewOpZero, NewOpOne, |
| Inst->getName() + "p_vec"); |
| VectorMap[Inst] = NewInst; |
| } |
| |
| void VectorBlockGenerator::copyStore(ScopStmt &Stmt, const StoreInst *Store, |
| ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps) { |
| const MemoryAccess &Access = Stmt.getAccessFor(Store); |
| |
| const Value *Pointer = Store->getPointerOperand(); |
| Value *Vector = getVectorValue(Stmt, Store->getValueOperand(), VectorMap, |
| ScalarMaps, getLoopForInst(Store)); |
| |
| // Make sure we have scalar values available to access the pointer to |
| // the data location. |
| extractScalarValues(Store, VectorMap, ScalarMaps); |
| |
| if (Access.isStrideOne(isl_map_copy(Schedule))) { |
| Type *VectorPtrType = getVectorPtrTy(Pointer, getVectorWidth()); |
| Value *NewPointer = generateLocationAccessed( |
| Stmt, Store, Pointer, ScalarMaps[0], GlobalMaps[0], VLTS[0]); |
| |
| Value *VectorPtr = |
| Builder.CreateBitCast(NewPointer, VectorPtrType, "vector_ptr"); |
| StoreInst *Store = Builder.CreateStore(Vector, VectorPtr); |
| |
| if (!Aligned) |
| Store->setAlignment(8); |
| } else { |
| for (unsigned i = 0; i < ScalarMaps.size(); i++) { |
| Value *Scalar = Builder.CreateExtractElement(Vector, Builder.getInt32(i)); |
| Value *NewPointer = generateLocationAccessed( |
| Stmt, Store, Pointer, ScalarMaps[i], GlobalMaps[i], VLTS[i]); |
| Builder.CreateStore(Scalar, NewPointer); |
| } |
| } |
| } |
| |
| bool VectorBlockGenerator::hasVectorOperands(const Instruction *Inst, |
| ValueMapT &VectorMap) { |
| for (Value *Operand : Inst->operands()) |
| if (VectorMap.count(Operand)) |
| return true; |
| return false; |
| } |
| |
| bool VectorBlockGenerator::extractScalarValues(const Instruction *Inst, |
| ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps) { |
| bool HasVectorOperand = false; |
| int VectorWidth = getVectorWidth(); |
| |
| for (Value *Operand : Inst->operands()) { |
| ValueMapT::iterator VecOp = VectorMap.find(Operand); |
| |
| if (VecOp == VectorMap.end()) |
| continue; |
| |
| HasVectorOperand = true; |
| Value *NewVector = VecOp->second; |
| |
| for (int i = 0; i < VectorWidth; ++i) { |
| ValueMapT &SM = ScalarMaps[i]; |
| |
| // If there is one scalar extracted, all scalar elements should have |
| // already been extracted by the code here. So no need to check for the |
| // existance of all of them. |
| if (SM.count(Operand)) |
| break; |
| |
| SM[Operand] = |
| Builder.CreateExtractElement(NewVector, Builder.getInt32(i)); |
| } |
| } |
| |
| return HasVectorOperand; |
| } |
| |
| void VectorBlockGenerator::copyInstScalarized(ScopStmt &Stmt, |
| const Instruction *Inst, |
| ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps) { |
| bool HasVectorOperand; |
| int VectorWidth = getVectorWidth(); |
| |
| HasVectorOperand = extractScalarValues(Inst, VectorMap, ScalarMaps); |
| |
| for (int VectorLane = 0; VectorLane < getVectorWidth(); VectorLane++) |
| BlockGenerator::copyInstruction(Stmt, Inst, ScalarMaps[VectorLane], |
| GlobalMaps[VectorLane], VLTS[VectorLane]); |
| |
| if (!VectorType::isValidElementType(Inst->getType()) || !HasVectorOperand) |
| return; |
| |
| // Make the result available as vector value. |
| VectorType *VectorType = VectorType::get(Inst->getType(), VectorWidth); |
| Value *Vector = UndefValue::get(VectorType); |
| |
| for (int i = 0; i < VectorWidth; i++) |
| Vector = Builder.CreateInsertElement(Vector, ScalarMaps[i][Inst], |
| Builder.getInt32(i)); |
| |
| VectorMap[Inst] = Vector; |
| } |
| |
| int VectorBlockGenerator::getVectorWidth() { return GlobalMaps.size(); } |
| |
| void VectorBlockGenerator::copyInstruction(ScopStmt &Stmt, |
| const Instruction *Inst, |
| ValueMapT &VectorMap, |
| VectorValueMapT &ScalarMaps) { |
| // Terminator instructions control the control flow. They are explicitly |
| // expressed in the clast and do not need to be copied. |
| if (Inst->isTerminator()) |
| return; |
| |
| if (canSynthesize(Inst, &LI, &SE, &Stmt.getParent()->getRegion())) |
| return; |
| |
| if (const LoadInst *Load = dyn_cast<LoadInst>(Inst)) { |
| generateLoad(Stmt, Load, VectorMap, ScalarMaps); |
| return; |
| } |
| |
| if (hasVectorOperands(Inst, VectorMap)) { |
| if (const StoreInst *Store = dyn_cast<StoreInst>(Inst)) { |
| copyStore(Stmt, Store, VectorMap, ScalarMaps); |
| return; |
| } |
| |
| if (const UnaryInstruction *Unary = dyn_cast<UnaryInstruction>(Inst)) { |
| copyUnaryInst(Stmt, Unary, VectorMap, ScalarMaps); |
| return; |
| } |
| |
| if (const BinaryOperator *Binary = dyn_cast<BinaryOperator>(Inst)) { |
| copyBinaryInst(Stmt, Binary, VectorMap, ScalarMaps); |
| return; |
| } |
| |
| // Falltrough: We generate scalar instructions, if we don't know how to |
| // generate vector code. |
| } |
| |
| copyInstScalarized(Stmt, Inst, VectorMap, ScalarMaps); |
| } |
| |
| void VectorBlockGenerator::copyStmt(ScopStmt &Stmt) { |
| assert(Stmt.isBlockStmt() && "TODO: Only block statements can be copied by " |
| "the vector block generator"); |
| |
| BasicBlock *BB = Stmt.getBasicBlock(); |
| BasicBlock *CopyBB = |
| SplitBlock(Builder.GetInsertBlock(), Builder.GetInsertPoint(), &DT, &LI); |
| CopyBB->setName("polly.stmt." + BB->getName()); |
| Builder.SetInsertPoint(CopyBB->begin()); |
| |
| // Create two maps that store the mapping from the original instructions of |
| // the old basic block to their copies in the new basic block. Those maps |
| // are basic block local. |
| // |
| // As vector code generation is supported there is one map for scalar values |
| // and one for vector values. |
| // |
| // In case we just do scalar code generation, the vectorMap is not used and |
| // the scalarMap has just one dimension, which contains the mapping. |
| // |
| // In case vector code generation is done, an instruction may either appear |
| // in the vector map once (as it is calculating >vectorwidth< values at a |
| // time. Or (if the values are calculated using scalar operations), it |
| // appears once in every dimension of the scalarMap. |
| VectorValueMapT ScalarBlockMap(getVectorWidth()); |
| ValueMapT VectorBlockMap; |
| |
| for (Instruction &Inst : *BB) |
| copyInstruction(Stmt, &Inst, VectorBlockMap, ScalarBlockMap); |
| } |
| |
| BasicBlock *RegionGenerator::repairDominance(BasicBlock *BB, |
| BasicBlock *BBCopy) { |
| |
| BasicBlock *BBIDom = DT.getNode(BB)->getIDom()->getBlock(); |
| BasicBlock *BBCopyIDom = BlockMap.lookup(BBIDom); |
| |
| if (BBCopyIDom) |
| DT.changeImmediateDominator(BBCopy, BBCopyIDom); |
| |
| return BBCopyIDom; |
| } |
| |
| void RegionGenerator::copyStmt(ScopStmt &Stmt, ValueMapT &GlobalMap, |
| LoopToScevMapT <S) { |
| assert(Stmt.isRegionStmt() && |
| "Only region statements can be copied by the block generator"); |
| |
| // Forget all old mappings. |
| BlockMap.clear(); |
| RegionMaps.clear(); |
| IncompletePHINodeMap.clear(); |
| |
| // The region represented by the statement. |
| Region *R = Stmt.getRegion(); |
| |
| // Create a dedicated entry for the region where we can reload all demoted |
| // inputs. |
| BasicBlock *EntryBB = R->getEntry(); |
| BasicBlock *EntryBBCopy = |
| SplitBlock(Builder.GetInsertBlock(), Builder.GetInsertPoint(), &DT, &LI); |
| EntryBBCopy->setName("polly.stmt." + EntryBB->getName() + ".entry"); |
| Builder.SetInsertPoint(EntryBBCopy->begin()); |
| |
| for (auto PI = pred_begin(EntryBB), PE = pred_end(EntryBB); PI != PE; ++PI) |
| if (!R->contains(*PI)) |
| BlockMap[*PI] = EntryBBCopy; |
| |
| // Iterate over all blocks in the region in a breadth-first search. |
| std::deque<BasicBlock *> Blocks; |
| SmallPtrSet<BasicBlock *, 8> SeenBlocks; |
| Blocks.push_back(EntryBB); |
| SeenBlocks.insert(EntryBB); |
| |
| while (!Blocks.empty()) { |
| BasicBlock *BB = Blocks.front(); |
| Blocks.pop_front(); |
| |
| // First split the block and update dominance information. |
| BasicBlock *BBCopy = splitBB(BB); |
| BasicBlock *BBCopyIDom = repairDominance(BB, BBCopy); |
| |
| // In order to remap PHI nodes we store also basic block mappings. |
| BlockMap[BB] = BBCopy; |
| |
| // Get the mapping for this block and initialize it with the mapping |
| // available at its immediate dominator (in the new region). |
| ValueMapT &RegionMap = RegionMaps[BBCopy]; |
| RegionMap = RegionMaps[BBCopyIDom]; |
| |
| // Copy the block with the BlockGenerator. |
| copyBB(Stmt, BB, BBCopy, RegionMap, GlobalMap, LTS); |
| |
| // In order to remap PHI nodes we store also basic block mappings. |
| BlockMap[BB] = BBCopy; |
| |
| // Add values to incomplete PHI nodes waiting for this block to be copied. |
| for (const PHINodePairTy &PHINodePair : IncompletePHINodeMap[BB]) |
| addOperandToPHI(Stmt, PHINodePair.first, PHINodePair.second, BB, |
| GlobalMap, LTS); |
| IncompletePHINodeMap[BB].clear(); |
| |
| // And continue with new successors inside the region. |
| for (auto SI = succ_begin(BB), SE = succ_end(BB); SI != SE; SI++) |
| if (R->contains(*SI) && SeenBlocks.insert(*SI).second) |
| Blocks.push_back(*SI); |
| } |
| |
| // Now create a new dedicated region exit block and add it to the region map. |
| BasicBlock *ExitBBCopy = |
| SplitBlock(Builder.GetInsertBlock(), Builder.GetInsertPoint(), &DT, &LI); |
| ExitBBCopy->setName("polly.stmt." + R->getExit()->getName() + ".exit"); |
| BlockMap[R->getExit()] = ExitBBCopy; |
| |
| repairDominance(R->getExit(), ExitBBCopy); |
| |
| // As the block generator doesn't handle control flow we need to add the |
| // region control flow by hand after all blocks have been copied. |
| for (BasicBlock *BB : SeenBlocks) { |
| |
| BranchInst *BI = cast<BranchInst>(BB->getTerminator()); |
| |
| BasicBlock *BBCopy = BlockMap[BB]; |
| Instruction *BICopy = BBCopy->getTerminator(); |
| |
| ValueMapT &RegionMap = RegionMaps[BBCopy]; |
| RegionMap.insert(BlockMap.begin(), BlockMap.end()); |
| |
| Builder.SetInsertPoint(BICopy); |
| copyInstScalar(Stmt, BI, RegionMap, GlobalMap, LTS); |
| BICopy->eraseFromParent(); |
| } |
| |
| // Add counting PHI nodes to all loops in the region that can be used as |
| // replacement for SCEVs refering to the old loop. |
| for (BasicBlock *BB : SeenBlocks) { |
| Loop *L = LI.getLoopFor(BB); |
| if (L == nullptr || L->getHeader() != BB) |
| continue; |
| |
| BasicBlock *BBCopy = BlockMap[BB]; |
| Value *NullVal = Builder.getInt32(0); |
| PHINode *LoopPHI = |
| PHINode::Create(Builder.getInt32Ty(), 2, "polly.subregion.iv"); |
| Instruction *LoopPHIInc = BinaryOperator::CreateAdd( |
| LoopPHI, Builder.getInt32(1), "polly.subregion.iv.inc"); |
| LoopPHI->insertBefore(BBCopy->begin()); |
| LoopPHIInc->insertBefore(BBCopy->getTerminator()); |
| |
| for (auto *PredBB : make_range(pred_begin(BB), pred_end(BB))) { |
| if (!R->contains(PredBB)) |
| continue; |
| if (L->contains(PredBB)) |
| LoopPHI->addIncoming(LoopPHIInc, BlockMap[PredBB]); |
| else |
| LoopPHI->addIncoming(NullVal, BlockMap[PredBB]); |
| } |
| |
| for (auto *PredBBCopy : make_range(pred_begin(BBCopy), pred_end(BBCopy))) |
| if (LoopPHI->getBasicBlockIndex(PredBBCopy) < 0) |
| LoopPHI->addIncoming(NullVal, PredBBCopy); |
| |
| LTS[L] = SE.getUnknown(LoopPHI); |
| } |
| |
| // Add all mappings from the region to the global map so outside uses will use |
| // the copied instructions. |
| for (auto &BBMap : RegionMaps) |
| GlobalMap.insert(BBMap.second.begin(), BBMap.second.end()); |
| |
| // Reset the old insert point for the build. |
| Builder.SetInsertPoint(ExitBBCopy->begin()); |
| } |
| |
| void RegionGenerator::generateScalarLoads(ScopStmt &Stmt, |
| const Instruction *Inst, |
| ValueMapT &BBMap) { |
| |
| // Inside a non-affine region PHI nodes are copied not demoted. Once the |
| // phi is copied it will reload all inputs from outside the region, hence |
| // we do not need to generate code for the read access of the operands of a |
| // PHI. |
| if (isa<PHINode>(Inst)) |
| return; |
| |
| return BlockGenerator::generateScalarLoads(Stmt, Inst, BBMap); |
| } |
| |
| void RegionGenerator::generateScalarStores(ScopStmt &Stmt, BasicBlock *BB, |
| ValueMapT &BBMap, |
| ValueMapT &GlobalMap) { |
| const Region &R = Stmt.getParent()->getRegion(); |
| |
| Region *StmtR = Stmt.getRegion(); |
| assert(StmtR && "Block statements need to use the generateScalarStores() " |
| "function in the BlockGenerator"); |
| |
| BasicBlock *ExitBB = StmtR->getExit(); |
| |
| // For region statements three kinds of scalar stores exists: |
| // (1) A definition used by a non-phi instruction outside the region. |
| // (2) A phi-instruction in the region entry. |
| // (3) A write to a phi instruction in the region exit. |
| // The last case is the tricky one since we do not know anymore which |
| // predecessor of the exit needs to store the operand value that doesn't |
| // have a definition in the region. Therefore, we have to check in each |
| // block in the region if we should store the value or not. |
| |
| // Iterate over all accesses in the given statement. |
| for (MemoryAccess *MA : Stmt) { |
| |
| // Skip non-scalar and read accesses. |
| if (!MA->isScalar() || MA->isRead()) |
| continue; |
| |
| Instruction *ScalarBase = cast<Instruction>(MA->getBaseAddr()); |
| Instruction *ScalarInst = MA->getAccessInstruction(); |
| PHINode *ScalarBasePHI = dyn_cast<PHINode>(ScalarBase); |
| |
| Value *ScalarValue = nullptr; |
| AllocaInst *ScalarAddr = nullptr; |
| |
| if (!ScalarBasePHI) { |
| // Case (1) |
| ScalarAddr = getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a"); |
| ScalarValue = ScalarInst; |
| } else if (ScalarBasePHI->getParent() != ExitBB) { |
| // Case (2) |
| assert(ScalarBasePHI->getParent() == StmtR->getEntry() && |
| "Bad PHI self write in non-affine region"); |
| assert(ScalarBase == ScalarInst && |
| "Bad PHI self write in non-affine region"); |
| ScalarAddr = getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a"); |
| ScalarValue = ScalarInst; |
| } else { |
| int PHIIdx = ScalarBasePHI->getBasicBlockIndex(BB); |
| // Skip accesses we will not handle in this basic block but in another one |
| // in the statement region. |
| if (PHIIdx < 0) |
| continue; |
| |
| // Case (3) |
| ScalarAddr = getOrCreateAlloca(ScalarBase, PHIOpMap, ".phiops"); |
| ScalarValue = ScalarBasePHI->getIncomingValue(PHIIdx); |
| } |
| |
| ScalarValue = |
| getNewScalarValue(ScalarValue, R, ScalarMap, BBMap, GlobalMap); |
| Builder.CreateStore(ScalarValue, ScalarAddr); |
| } |
| } |
| |
| void RegionGenerator::addOperandToPHI(ScopStmt &Stmt, const PHINode *PHI, |
| PHINode *PHICopy, BasicBlock *IncomingBB, |
| ValueMapT &GlobalMap, |
| LoopToScevMapT <S) { |
| Region *StmtR = Stmt.getRegion(); |
| |
| // If the incoming block was not yet copied mark this PHI as incomplete. |
| // Once the block will be copied the incoming value will be added. |
| BasicBlock *BBCopy = BlockMap[IncomingBB]; |
| if (!BBCopy) { |
| assert(StmtR->contains(IncomingBB) && |
| "Bad incoming block for PHI in non-affine region"); |
| IncompletePHINodeMap[IncomingBB].push_back(std::make_pair(PHI, PHICopy)); |
| return; |
| } |
| |
| Value *OpCopy = nullptr; |
| if (StmtR->contains(IncomingBB)) { |
| assert(RegionMaps.count(BBCopy) && |
| "Incoming PHI block did not have a BBMap"); |
| ValueMapT &BBCopyMap = RegionMaps[BBCopy]; |
| |
| Value *Op = PHI->getIncomingValueForBlock(IncomingBB); |
| OpCopy = |
| getNewValue(Stmt, Op, BBCopyMap, GlobalMap, LTS, getLoopForInst(PHI)); |
| } else { |
| |
| if (PHICopy->getBasicBlockIndex(BBCopy) >= 0) |
| return; |
| |
| AllocaInst *PHIOpAddr = |
| getOrCreateAlloca(const_cast<PHINode *>(PHI), PHIOpMap, ".phiops"); |
| OpCopy = new LoadInst(PHIOpAddr, PHIOpAddr->getName() + ".reload", |
| BlockMap[IncomingBB]->getTerminator()); |
| } |
| |
| assert(OpCopy && "Incoming PHI value was not copied properly"); |
| assert(BBCopy && "Incoming PHI block was not copied properly"); |
| PHICopy->addIncoming(OpCopy, BBCopy); |
| } |
| |
| Value *RegionGenerator::copyPHIInstruction(ScopStmt &Stmt, const PHINode *PHI, |
| ValueMapT &BBMap, |
| ValueMapT &GlobalMap, |
| LoopToScevMapT <S) { |
| unsigned NumIncoming = PHI->getNumIncomingValues(); |
| PHINode *PHICopy = |
| Builder.CreatePHI(PHI->getType(), NumIncoming, "polly." + PHI->getName()); |
| PHICopy->moveBefore(PHICopy->getParent()->getFirstNonPHI()); |
| BBMap[PHI] = PHICopy; |
| |
| for (unsigned u = 0; u < NumIncoming; u++) |
| addOperandToPHI(Stmt, PHI, PHICopy, PHI->getIncomingBlock(u), GlobalMap, |
| LTS); |
| return PHICopy; |
| } |