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llvm-project/polly/lib/CodeGen/BlockGenerators.cpp

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//===--- 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 &LTS, 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");
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 &LTS) {
// 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 &LTS) {
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 &LTS) {
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 &LTS) {
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 &LTS) {
// 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 &LTS) {
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 &LTS) {
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 &LTS) {
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 &LTS) {
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(BBCopy);
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 &LTS) {
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 &LTS) {
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;
}
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