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llvm-project/polly/lib/Analysis/TempScopInfo.cpp

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//===---------- TempScopInfo.cpp - Extract TempScops ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Collect information about the control flow regions detected by the Scop
// detection, such that this information can be translated info its polyhedral
// representation.
//
//===----------------------------------------------------------------------===//
#include "polly/TempScopInfo.h"
#include "polly/LinkAllPasses.h"
#include "polly/Support/AffineSCEVIterator.h"
#include "polly/Support/GICHelper.h"
#include "polly/Support/ScopHelper.h"
#include "polly/Support/SCEVValidator.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/RegionIterator.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/ADT/STLExtras.h"
#define DEBUG_TYPE "polly-analyze-ir"
#include "llvm/Support/Debug.h"
using namespace llvm;
using namespace polly;
//===----------------------------------------------------------------------===//
/// Helper Class
SCEVAffFunc::SCEVAffFunc(const SCEV *S, SCEVAffFuncType Type, Region &R,
ParamSetType &Params, LoopInfo *LI,
ScalarEvolution *SE)
: ElemBytes(0), FuncType(Type) {
assert(S && "S can not be null!");
assert(!isa<SCEVCouldNotCompute>(S) && "Non affine function in Scop");
OriginalSCEV = S;
for (AffineSCEVIterator I = affine_begin(S, SE), E = affine_end();
I != E; ++I) {
// The constant part must be a SCEVConstant.
// TODO: support sizeof in coefficient.
assert(isa<SCEVConstant>(I->second)
&& "Expected SCEVConst in coefficient!");
const SCEV *Var = I->first;
if (isa<SCEVConstant>(Var)) // Extract the constant part.
// Add the translation component.
TransComp = I->second;
else if (Var->getType()->isPointerTy()) { // Extract the base address.
const SCEVUnknown *Addr = dyn_cast<SCEVUnknown>(Var);
assert(Addr && "Broken SCEV detected!");
BaseAddr = Addr->getValue();
} else { // Extract other affine components.
LnrTrans.insert(*I);
if (isIndVar(Var, R, *LI, *SE))
continue;
assert(isParameter(Var, R, *LI, *SE)
&& "Found non affine function in Scop!");
Params.insert(Var);
}
}
}
void SCEVAffFunc::print(raw_ostream &OS, bool PrintInequality) const {
// Print BaseAddr.
if (isDataRef()) {
OS << (isRead() ? "Reads" : "Writes") << " ";
WriteAsOperand(OS, getBaseAddr(), false);
OS << "[";
}
for (LnrTransSet::const_iterator I = LnrTrans.begin(), E = LnrTrans.end();
I != E; ++I)
OS << *I->second << " * " << *I->first << " + ";
if (TransComp)
OS << *TransComp;
if (isDataRef())
OS << "]";
if (!PrintInequality)
return;
if (getType() == GE)
OS << " >= 0";
else if (getType() == Eq)
OS << " == 0";
else if (getType() == Ne)
OS << " != 0";
}
void SCEVAffFunc::dump() const {
print(errs());
}
inline raw_ostream &operator<<(raw_ostream &OS, const SCEVAffFunc &AffFunc) {
AffFunc.print(OS);
return OS;
}
void Comparison::print(raw_ostream &OS) const {
// Not yet implemented.
}
/// Helper function to print the condition
static void printBBCond(raw_ostream &OS, const BBCond &Cond) {
assert(!Cond.empty() && "Unexpected empty condition!");
Cond[0].print(OS);
for (unsigned i = 1, e = Cond.size(); i != e; ++i) {
OS << " && ";
Cond[i].print(OS);
}
}
inline raw_ostream &operator<<(raw_ostream &OS, const BBCond &Cond) {
printBBCond(OS, Cond);
return OS;
}
//===----------------------------------------------------------------------===//
// TempScop implementation
TempScop::~TempScop() {
if (MayASInfo) delete MayASInfo;
}
void TempScop::print(raw_ostream &OS, ScalarEvolution *SE, LoopInfo *LI) const {
OS << "Scop: " << R.getNameStr() << "\tParameters: (";
// Print Parameters.
for (ParamSetType::const_iterator PI = Params.begin(), PE = Params.end();
PI != PE; ++PI)
OS << **PI << ", ";
OS << "), Max Loop Depth: "<< MaxLoopDepth <<"\n";
printDetail(OS, SE, LI, &R, 0);
}
void TempScop::printDetail(llvm::raw_ostream &OS, ScalarEvolution *SE,
LoopInfo *LI, const Region *CurR,
unsigned ind) const {
// Print the loop bounds, if the current region is a loop.
LoopBoundMapType::const_iterator at = LoopBounds.find(castToLoop(*CurR, *LI));
if (at != LoopBounds.end()) {
OS.indent(ind) << "Bounds of Loop: " << at->first->getHeader()->getName()
<< ":\t{ ";
OS << *(at->second);
OS << " }\n";
ind += 2;
}
// Iterate over the region nodes of this Scop to print the access functions
// and loop bounds.
for (Region::const_element_iterator I = CurR->element_begin(),
E = CurR->element_end(); I != E; ++I) {
if (I->isSubRegion()) {
Region *subR = I->getNodeAs<Region>();
printDetail(OS, SE, LI, subR, ind + 2);
} else {
BasicBlock *BB = I->getNodeAs<BasicBlock>();
if (const AccFuncSetType *AccFunc = getAccessFunctions(BB)) {
OS.indent(ind) << "BB: " << BB->getName() << "{\n";
for (AccFuncSetType::const_iterator FI = AccFunc->begin(),
FE = AccFunc->end(); FI != FE; ++FI) {
const SCEVAffFunc &AF = FI->first;
const Value *Ptr = AF.getBaseAddr();
OS.indent(ind + 2) << AF << " Refs: ";
for (MayAliasSetInfo::const_alias_iterator
MI = MayASInfo->alias_begin(Ptr), ME = MayASInfo->alias_end(Ptr);
MI != ME; ++MI) {
MI->second->print(OS);
OS << ", ";
}
OS << '\n';
}
OS.indent(ind) << "}\n";
}
}
}
}
void TempScopInfo::buildAffineFunction(const SCEV *S, SCEVAffFunc &FuncToBuild,
Region &R, ParamSetType &Params) const {
assert(S && "S can not be null!");
assert(!isa<SCEVCouldNotCompute>(S)
&& "Un Expect broken affine function in Scop!");
for (AffineSCEVIterator I = affine_begin(S, SE), E = affine_end();
I != E; ++I) {
// The constant part must be a SCEVConstant.
// TODO: support sizeof in coefficient.
assert(isa<SCEVConstant>(I->second) && "Expect SCEVConst in coefficient!");
const SCEV *Var = I->first;
// Extract the constant part
if (isa<SCEVConstant>(Var))
// Add the translation component
FuncToBuild.TransComp = I->second;
else if (Var->getType()->isPointerTy()) { // Extract the base address
const SCEVUnknown *BaseAddr = dyn_cast<SCEVUnknown>(Var);
assert(BaseAddr && "Why we got a broken scev?");
FuncToBuild.BaseAddr = BaseAddr->getValue();
} else { // Extract other affine components.
FuncToBuild.LnrTrans.insert(*I);
// Do not add the indvar to the parameter list.
if (!isIndVar(Var, R, *LI, *SE)) {
DEBUG(dbgs() << "Non indvar: "<< *Var << '\n');
assert(isParameter(Var, R, *LI, *SE)
&& "Find non affine function in scop!");
Params.insert(Var);
}
}
}
}
void TempScopInfo::buildAccessFunctions(Region &R, ParamSetType &Parameter,
BasicBlock &BB) {
AccFuncSetType Functions;
for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I) {
Instruction &Inst = *I;
if (isa<LoadInst>(&Inst) || isa<StoreInst>(&Inst)) {
unsigned Size;
enum SCEVAffFunc::SCEVAffFuncType Type;
if (LoadInst *Load = dyn_cast<LoadInst>(&Inst)) {
Size = TD->getTypeStoreSize(Load->getType());
Type = SCEVAffFunc::ReadMem;
} else {
StoreInst *Store = cast<StoreInst>(&Inst);
Size = TD->getTypeStoreSize(Store->getValueOperand()->getType());
Type = SCEVAffFunc::WriteMem;
}
const SCEV *AccessFunction = SE->getSCEV(getPointerOperand(Inst));
Functions.push_back(
std::make_pair(SCEVAffFunc(Type, AccessFunction, Size), &Inst));
buildAffineFunction(AccessFunction, Functions.back().first, R, Parameter);
}
}
if (Functions.empty())
return;
AccFuncSetType &Accs = AccFuncMap[&BB];
Accs.insert(Accs.end(), Functions.begin(), Functions.end());
}
void TempScopInfo::buildLoopBounds(TempScop &Scop) {
Region &R = Scop.getMaxRegion();
unsigned MaxLoopDepth = 0;
for (Region::block_iterator I = R.block_begin(), E = R.block_end();
I != E; ++I) {
Loop *L = LI->getLoopFor(I->getNodeAs<BasicBlock>());
if (!L || !R.contains(L))
continue;
if (LoopBounds.find(L) != LoopBounds.end())
continue;
const SCEV *BackedgeTakenCount = SE->getBackedgeTakenCount(L);
LoopBounds[L] = BackedgeTakenCount;
// FIXME: Do not build TempSCEVAffFunc. It is not needed anywhere else
// and only build to register the parameters in this SCoP. We should
// move this functionality to the ScopDetection.
SCEVAffFunc Temp(SCEVAffFunc::Eq, BackedgeTakenCount);
buildAffineFunction(BackedgeTakenCount, Temp, Scop.getMaxRegion(),
Scop.getParamSet());
Loop *OL = R.outermostLoopInRegion(L);
unsigned LoopDepth = L->getLoopDepth() - OL->getLoopDepth() + 1;
if (LoopDepth > MaxLoopDepth)
MaxLoopDepth = LoopDepth;
}
Scop.MaxLoopDepth = MaxLoopDepth;
}
void TempScopInfo::buildAffineCondition(Value &V, bool inverted,
Comparison **Comp,
TempScop &Scop) const {
Region &R = Scop.getMaxRegion();
ParamSetType &Params = Scop.getParamSet();
if (ConstantInt *C = dyn_cast<ConstantInt>(&V)) {
// If this is always true condition, we will create 1 >= 0,
// otherwise we will create 1 == 0.
SCEVAffFunc *AffLHS = new SCEVAffFunc(SE->getConstant(C->getType(), 0),
SCEVAffFunc::Eq, R, Params, LI, SE);
SCEVAffFunc *AffRHS = new SCEVAffFunc(SE->getConstant(C->getType(), 1),
SCEVAffFunc::Eq, R, Params, LI, SE);
if (C->isOne() == inverted)
*Comp = new Comparison(AffRHS, AffLHS, ICmpInst::ICMP_NE);
else
*Comp = new Comparison(AffLHS, AffLHS, ICmpInst::ICMP_EQ);
return;
}
ICmpInst *ICmp = dyn_cast<ICmpInst>(&V);
assert(ICmp && "Only ICmpInst of constant as condition supported!");
const SCEV *LHS = SE->getSCEV(ICmp->getOperand(0)),
*RHS = SE->getSCEV(ICmp->getOperand(1));
ICmpInst::Predicate Pred = ICmp->getPredicate();
// Invert the predicate if needed.
if (inverted)
Pred = ICmpInst::getInversePredicate(Pred);
SCEVAffFunc *AffLHS = new SCEVAffFunc(LHS, SCEVAffFunc::Eq, R, Params, LI,
SE);
SCEVAffFunc *AffRHS = new SCEVAffFunc(RHS, SCEVAffFunc::Eq, R, Params, LI,
SE);
switch (Pred) {
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_UGE:
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_ULE:
// TODO: At the moment we need to see everything as signed. This is an
// correctness issue that needs to be solved.
//AffLHS->setUnsigned();
//AffRHS->setUnsigned();
break;
default:
break;
}
*Comp = new Comparison(AffLHS, AffRHS, Pred);
}
void TempScopInfo::buildCondition(BasicBlock *BB, BasicBlock *RegionEntry,
TempScop &Scop) {
BBCond Cond;
DomTreeNode *BBNode = DT->getNode(BB), *EntryNode = DT->getNode(RegionEntry);
assert(BBNode && EntryNode && "Get null node while building condition!");
// Walk up the dominance tree until reaching the entry node. Add all
// conditions on the path to BB except if BB postdominates the block
// containing the condition.
while (BBNode != EntryNode) {
BasicBlock *CurBB = BBNode->getBlock();
BBNode = BBNode->getIDom();
assert(BBNode && "BBNode should not reach the root node!");
if (PDT->dominates(CurBB, BBNode->getBlock()))
continue;
BranchInst *Br = dyn_cast<BranchInst>(BBNode->getBlock()->getTerminator());
assert(Br && "A Valid Scop should only contain branch instruction");
if (Br->isUnconditional())
continue;
// Is BB on the ELSE side of the branch?
bool inverted = DT->dominates(Br->getSuccessor(1), BB);
Comparison *Cmp;
buildAffineCondition(*(Br->getCondition()), inverted, &Cmp, Scop);
Cond.push_back(*Cmp);
}
if (!Cond.empty())
BBConds[BB] = Cond;
}
TempScop *TempScopInfo::buildTempScop(Region &R) {
TempScop *TScop = new TempScop(R, LoopBounds, BBConds, AccFuncMap);
for (Region::block_iterator I = R.block_begin(), E = R.block_end();
I != E; ++I) {
BasicBlock *BB = I->getNodeAs<BasicBlock>();
buildAccessFunctions(R, TScop->getParamSet(), *BB);
buildCondition(BB, R.getEntry(), *TScop);
}
buildLoopBounds(*TScop);
// Build the MayAliasSets.
TScop->MayASInfo->buildMayAliasSets(*TScop, *AA);
return TScop;
}
TempScop *TempScopInfo::getTempScop(const Region *R) const {
TempScopMapType::const_iterator at = TempScops.find(R);
return at == TempScops.end() ? 0 : at->second;
}
void TempScopInfo::print(raw_ostream &OS, const Module *) const {
for (TempScopMapType::const_iterator I = TempScops.begin(),
E = TempScops.end(); I != E; ++I)
I->second->print(OS, SE, LI);
}
bool TempScopInfo::runOnFunction(Function &F) {
DT = &getAnalysis<DominatorTree>();
PDT = &getAnalysis<PostDominatorTree>();
SE = &getAnalysis<ScalarEvolution>();
LI = &getAnalysis<LoopInfo>();
SD = &getAnalysis<ScopDetection>();
AA = &getAnalysis<AliasAnalysis>();
TD = &getAnalysis<TargetData>();
for (ScopDetection::iterator I = SD->begin(), E = SD->end(); I != E; ++I) {
Region *R = const_cast<Region*>(*I);
TempScops.insert(std::make_pair(R, buildTempScop(*R)));
}
return false;
}
void TempScopInfo::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetData>();
AU.addRequiredTransitive<DominatorTree>();
AU.addRequiredTransitive<PostDominatorTree>();
AU.addRequiredTransitive<LoopInfo>();
AU.addRequiredTransitive<ScalarEvolution>();
AU.addRequiredTransitive<ScopDetection>();
AU.addRequiredID(IndependentBlocksID);
AU.addRequired<AliasAnalysis>();
AU.setPreservesAll();
}
TempScopInfo::~TempScopInfo() {
clear();
}
void TempScopInfo::clear() {
BBConds.clear();
LoopBounds.clear();
AccFuncMap.clear();
DeleteContainerSeconds(TempScops);
TempScops.clear();
}
//===----------------------------------------------------------------------===//
// TempScop information extraction pass implement
char TempScopInfo::ID = 0;
INITIALIZE_PASS_BEGIN(TempScopInfo, "polly-analyze-ir",
"Polly - Analyse the LLVM-IR in the detected regions",
false, false)
INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
INITIALIZE_PASS_DEPENDENCY(DominatorTree)
INITIALIZE_PASS_DEPENDENCY(LoopInfo)
INITIALIZE_PASS_DEPENDENCY(PostDominatorTree)
INITIALIZE_PASS_DEPENDENCY(RegionInfo)
INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
INITIALIZE_PASS_DEPENDENCY(TargetData)
INITIALIZE_PASS_END(TempScopInfo, "polly-analyze-ir",
"Polly - Analyse the LLVM-IR in the detected regions",
false, false)
Pass *polly::createTempScopInfoPass() {
return new TempScopInfo();
}
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