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llvm / polly / refs/heads/release_38 / . / lib / Analysis / ScopInfo.cpp
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//===--------- ScopInfo.cpp - Create Scops from LLVM IR ------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Create a polyhedral description for a static control flow region.
//
// The pass creates a polyhedral description of the Scops detected by the Scop
// detection derived from their LLVM-IR code.
//
// This representation is shared among several tools in the polyhedral
// community, which are e.g. Cloog, Pluto, Loopo, Graphite.
//
//===----------------------------------------------------------------------===//
#include "polly/ScopInfo.h"
#include "polly/LinkAllPasses.h"
#include "polly/Options.h"
#include "polly/Support/GICHelper.h"
#include "polly/Support/SCEVValidator.h"
#include "polly/Support/ScopHelper.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopIterator.h"
#include "llvm/Analysis/RegionIterator.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/Support/Debug.h"
#include "isl/aff.h"
#include "isl/constraint.h"
#include "isl/local_space.h"
#include "isl/map.h"
#include "isl/options.h"
#include "isl/printer.h"
#include "isl/schedule.h"
#include "isl/schedule_node.h"
#include "isl/set.h"
#include "isl/union_map.h"
#include "isl/union_set.h"
#include "isl/val.h"
#include <sstream>
#include <string>
#include <vector>
using namespace llvm;
using namespace polly;
#define DEBUG_TYPE "polly-scops"
STATISTIC(ScopFound, "Number of valid Scops");
STATISTIC(RichScopFound, "Number of Scops containing a loop");
// The maximal number of basic sets we allow during domain construction to
// be created. More complex scops will result in very high compile time and
// are also unlikely to result in good code
static int const MaxConjunctsInDomain = 20;
static cl::opt<bool> ModelReadOnlyScalars(
"polly-analyze-read-only-scalars",
cl::desc("Model read-only scalar values in the scop description"),
cl::Hidden, cl::ZeroOrMore, cl::init(true), cl::cat(PollyCategory));
// Multiplicative reductions can be disabled separately as these kind of
// operations can overflow easily. Additive reductions and bit operations
// are in contrast pretty stable.
static cl::opt<bool> DisableMultiplicativeReductions(
"polly-disable-multiplicative-reductions",
cl::desc("Disable multiplicative reductions"), cl::Hidden, cl::ZeroOrMore,
cl::init(false), cl::cat(PollyCategory));
static cl::opt<unsigned> RunTimeChecksMaxParameters(
"polly-rtc-max-parameters",
cl::desc("The maximal number of parameters allowed in RTCs."), cl::Hidden,
cl::ZeroOrMore, cl::init(8), cl::cat(PollyCategory));
static cl::opt<unsigned> RunTimeChecksMaxArraysPerGroup(
"polly-rtc-max-arrays-per-group",
cl::desc("The maximal number of arrays to compare in each alias group."),
cl::Hidden, cl::ZeroOrMore, cl::init(20), cl::cat(PollyCategory));
static cl::opt<std::string> UserContextStr(
"polly-context", cl::value_desc("isl parameter set"),
cl::desc("Provide additional constraints on the context parameters"),
cl::init(""), cl::cat(PollyCategory));
static cl::opt<bool> DetectReductions("polly-detect-reductions",
cl::desc("Detect and exploit reductions"),
cl::Hidden, cl::ZeroOrMore,
cl::init(true), cl::cat(PollyCategory));
static cl::opt<int> MaxDisjunctsAssumed(
"polly-max-disjuncts-assumed",
cl::desc("The maximal number of disjuncts we allow in the assumption "
"context (this bounds compile time)"),
cl::Hidden, cl::ZeroOrMore, cl::init(150), cl::cat(PollyCategory));
static cl::opt<bool> IgnoreIntegerWrapping(
"polly-ignore-integer-wrapping",
cl::desc("Do not build run-time checks to proof absence of integer "
"wrapping"),
cl::Hidden, cl::ZeroOrMore, cl::init(false), cl::cat(PollyCategory));
//===----------------------------------------------------------------------===//
// Create a sequence of two schedules. Either argument may be null and is
// interpreted as the empty schedule. Can also return null if both schedules are
// empty.
static __isl_give isl_schedule *
combineInSequence(__isl_take isl_schedule *Prev,
__isl_take isl_schedule *Succ) {
if (!Prev)
return Succ;
if (!Succ)
return Prev;
return isl_schedule_sequence(Prev, Succ);
}
static __isl_give isl_set *addRangeBoundsToSet(__isl_take isl_set *S,
const ConstantRange &Range,
int dim,
enum isl_dim_type type) {
isl_val *V;
isl_ctx *ctx = isl_set_get_ctx(S);
bool useLowerUpperBound = Range.isSignWrappedSet() && !Range.isFullSet();
const auto LB = useLowerUpperBound ? Range.getLower() : Range.getSignedMin();
V = isl_valFromAPInt(ctx, LB, true);
isl_set *SLB = isl_set_lower_bound_val(isl_set_copy(S), type, dim, V);
const auto UB = useLowerUpperBound ? Range.getUpper() : Range.getSignedMax();
V = isl_valFromAPInt(ctx, UB, true);
if (useLowerUpperBound)
V = isl_val_sub_ui(V, 1);
isl_set *SUB = isl_set_upper_bound_val(S, type, dim, V);
if (useLowerUpperBound)
return isl_set_union(SLB, SUB);
else
return isl_set_intersect(SLB, SUB);
}
static const ScopArrayInfo *identifyBasePtrOriginSAI(Scop *S, Value *BasePtr) {
LoadInst *BasePtrLI = dyn_cast<LoadInst>(BasePtr);
if (!BasePtrLI)
return nullptr;
if (!S->getRegion().contains(BasePtrLI))
return nullptr;
ScalarEvolution &SE = *S->getSE();
auto *OriginBaseSCEV =
SE.getPointerBase(SE.getSCEV(BasePtrLI->getPointerOperand()));
if (!OriginBaseSCEV)
return nullptr;
auto *OriginBaseSCEVUnknown = dyn_cast<SCEVUnknown>(OriginBaseSCEV);
if (!OriginBaseSCEVUnknown)
return nullptr;
return S->getScopArrayInfo(OriginBaseSCEVUnknown->getValue(),
ScopArrayInfo::MK_Array);
}
ScopArrayInfo::ScopArrayInfo(Value *BasePtr, Type *ElementType, isl_ctx *Ctx,
ArrayRef<const SCEV *> Sizes, enum MemoryKind Kind,
const DataLayout &DL, Scop *S)
: BasePtr(BasePtr), ElementType(ElementType), Kind(Kind), DL(DL), S(*S) {
std::string BasePtrName =
getIslCompatibleName("MemRef_", BasePtr, Kind == MK_PHI ? "__phi" : "");
Id = isl_id_alloc(Ctx, BasePtrName.c_str(), this);
updateSizes(Sizes);
BasePtrOriginSAI = identifyBasePtrOriginSAI(S, BasePtr);
if (BasePtrOriginSAI)
const_cast<ScopArrayInfo *>(BasePtrOriginSAI)->addDerivedSAI(this);
}
__isl_give isl_space *ScopArrayInfo::getSpace() const {
auto Space =
isl_space_set_alloc(isl_id_get_ctx(Id), 0, getNumberOfDimensions());
Space = isl_space_set_tuple_id(Space, isl_dim_set, isl_id_copy(Id));
return Space;
}
bool ScopArrayInfo::updateSizes(ArrayRef<const SCEV *> NewSizes) {
int SharedDims = std::min(NewSizes.size(), DimensionSizes.size());
int ExtraDimsNew = NewSizes.size() - SharedDims;
int ExtraDimsOld = DimensionSizes.size() - SharedDims;
for (int i = 0; i < SharedDims; i++)
if (NewSizes[i + ExtraDimsNew] != DimensionSizes[i + ExtraDimsOld])
return false;
if (DimensionSizes.size() >= NewSizes.size())
return true;
DimensionSizes.clear();
DimensionSizes.insert(DimensionSizes.begin(), NewSizes.begin(),
NewSizes.end());
for (isl_pw_aff *Size : DimensionSizesPw)
isl_pw_aff_free(Size);
DimensionSizesPw.clear();
for (const SCEV *Expr : DimensionSizes) {
isl_pw_aff *Size = S.getPwAff(Expr);
DimensionSizesPw.push_back(Size);
}
return true;
}
ScopArrayInfo::~ScopArrayInfo() {
isl_id_free(Id);
for (isl_pw_aff *Size : DimensionSizesPw)
isl_pw_aff_free(Size);
}
std::string ScopArrayInfo::getName() const { return isl_id_get_name(Id); }
int ScopArrayInfo::getElemSizeInBytes() const {
return DL.getTypeAllocSize(ElementType);
}
isl_id *ScopArrayInfo::getBasePtrId() const { return isl_id_copy(Id); }
void ScopArrayInfo::dump() const { print(errs()); }
void ScopArrayInfo::print(raw_ostream &OS, bool SizeAsPwAff) const {
OS.indent(8) << *getElementType() << " " << getName();
if (getNumberOfDimensions() > 0)
OS << "[*]";
for (unsigned u = 1; u < getNumberOfDimensions(); u++) {
OS << "[";
if (SizeAsPwAff) {
auto Size = getDimensionSizePw(u);
OS << " " << Size << " ";
isl_pw_aff_free(Size);
} else {
OS << *getDimensionSize(u);
}
OS << "]";
}
OS << ";";
if (BasePtrOriginSAI)
OS << " [BasePtrOrigin: " << BasePtrOriginSAI->getName() << "]";
OS << " // Element size " << getElemSizeInBytes() << "\n";
}
const ScopArrayInfo *
ScopArrayInfo::getFromAccessFunction(__isl_keep isl_pw_multi_aff *PMA) {
isl_id *Id = isl_pw_multi_aff_get_tuple_id(PMA, isl_dim_out);
assert(Id && "Output dimension didn't have an ID");
return getFromId(Id);
}
const ScopArrayInfo *ScopArrayInfo::getFromId(isl_id *Id) {
void *User = isl_id_get_user(Id);
const ScopArrayInfo *SAI = static_cast<ScopArrayInfo *>(User);
isl_id_free(Id);
return SAI;
}
void MemoryAccess::updateDimensionality() {
auto ArraySpace = getScopArrayInfo()->getSpace();
auto AccessSpace = isl_space_range(isl_map_get_space(AccessRelation));
auto DimsArray = isl_space_dim(ArraySpace, isl_dim_set);
auto DimsAccess = isl_space_dim(AccessSpace, isl_dim_set);
auto DimsMissing = DimsArray - DimsAccess;
auto Map = isl_map_from_domain_and_range(isl_set_universe(AccessSpace),
isl_set_universe(ArraySpace));
for (unsigned i = 0; i < DimsMissing; i++)
Map = isl_map_fix_si(Map, isl_dim_out, i, 0);
for (unsigned i = DimsMissing; i < DimsArray; i++)
Map = isl_map_equate(Map, isl_dim_in, i - DimsMissing, isl_dim_out, i);
AccessRelation = isl_map_apply_range(AccessRelation, Map);
assumeNoOutOfBound();
}
const std::string
MemoryAccess::getReductionOperatorStr(MemoryAccess::ReductionType RT) {
switch (RT) {
case MemoryAccess::RT_NONE:
llvm_unreachable("Requested a reduction operator string for a memory "
"access which isn't a reduction");
case MemoryAccess::RT_ADD:
return "+";
case MemoryAccess::RT_MUL:
return "*";
case MemoryAccess::RT_BOR:
return "|";
case MemoryAccess::RT_BXOR:
return "^";
case MemoryAccess::RT_BAND:
return "&";
}
llvm_unreachable("Unknown reduction type");
return "";
}
/// @brief Return the reduction type for a given binary operator
static MemoryAccess::ReductionType getReductionType(const BinaryOperator *BinOp,
const Instruction *Load) {
if (!BinOp)
return MemoryAccess::RT_NONE;
switch (BinOp->getOpcode()) {
case Instruction::FAdd:
if (!BinOp->hasUnsafeAlgebra())
return MemoryAccess::RT_NONE;
// Fall through
case Instruction::Add:
return MemoryAccess::RT_ADD;
case Instruction::Or:
return MemoryAccess::RT_BOR;
case Instruction::Xor:
return MemoryAccess::RT_BXOR;
case Instruction::And:
return MemoryAccess::RT_BAND;
case Instruction::FMul:
if (!BinOp->hasUnsafeAlgebra())
return MemoryAccess::RT_NONE;
// Fall through
case Instruction::Mul:
if (DisableMultiplicativeReductions)
return MemoryAccess::RT_NONE;
return MemoryAccess::RT_MUL;
default:
return MemoryAccess::RT_NONE;
}
}
/// @brief Derive the individual index expressions from a GEP instruction
///
/// This function optimistically assumes the GEP references into a fixed size
/// array. If this is actually true, this function returns a list of array
/// subscript expressions as SCEV as well as a list of integers describing
/// the size of the individual array dimensions. Both lists have either equal
/// length of the size list is one element shorter in case there is no known
/// size available for the outermost array dimension.
///
/// @param GEP The GetElementPtr instruction to analyze.
///
/// @return A tuple with the subscript expressions and the dimension sizes.
static std::tuple<std::vector<const SCEV *>, std::vector<int>>
getIndexExpressionsFromGEP(GetElementPtrInst *GEP, ScalarEvolution &SE) {
std::vector<const SCEV *> Subscripts;
std::vector<int> Sizes;
Type *Ty = GEP->getPointerOperandType();
bool DroppedFirstDim = false;
for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
const SCEV *Expr = SE.getSCEV(GEP->getOperand(i));
if (i == 1) {
if (auto PtrTy = dyn_cast<PointerType>(Ty)) {
Ty = PtrTy->getElementType();
} else if (auto ArrayTy = dyn_cast<ArrayType>(Ty)) {
Ty = ArrayTy->getElementType();
} else {
Subscripts.clear();
Sizes.clear();
break;
}
if (auto Const = dyn_cast<SCEVConstant>(Expr))
if (Const->getValue()->isZero()) {
DroppedFirstDim = true;
continue;
}
Subscripts.push_back(Expr);
continue;
}
auto ArrayTy = dyn_cast<ArrayType>(Ty);
if (!ArrayTy) {
Subscripts.clear();
Sizes.clear();
break;
}
Subscripts.push_back(Expr);
if (!(DroppedFirstDim && i == 2))
Sizes.push_back(ArrayTy->getNumElements());
Ty = ArrayTy->getElementType();
}
return std::make_tuple(Subscripts, Sizes);
}
MemoryAccess::~MemoryAccess() {
isl_id_free(Id);
isl_map_free(AccessRelation);
isl_map_free(NewAccessRelation);
}
const ScopArrayInfo *MemoryAccess::getScopArrayInfo() const {
isl_id *ArrayId = getArrayId();
void *User = isl_id_get_user(ArrayId);
const ScopArrayInfo *SAI = static_cast<ScopArrayInfo *>(User);
isl_id_free(ArrayId);
return SAI;
}
__isl_give isl_id *MemoryAccess::getArrayId() const {
return isl_map_get_tuple_id(AccessRelation, isl_dim_out);
}
__isl_give isl_pw_multi_aff *MemoryAccess::applyScheduleToAccessRelation(
__isl_take isl_union_map *USchedule) const {
isl_map *Schedule, *ScheduledAccRel;
isl_union_set *UDomain;
UDomain = isl_union_set_from_set(getStatement()->getDomain());
USchedule = isl_union_map_intersect_domain(USchedule, UDomain);
Schedule = isl_map_from_union_map(USchedule);
ScheduledAccRel = isl_map_apply_domain(getAccessRelation(), Schedule);
return isl_pw_multi_aff_from_map(ScheduledAccRel);
}
__isl_give isl_map *MemoryAccess::getOriginalAccessRelation() const {
return isl_map_copy(AccessRelation);
}
std::string MemoryAccess::getOriginalAccessRelationStr() const {
return stringFromIslObj(AccessRelation);
}
__isl_give isl_space *MemoryAccess::getOriginalAccessRelationSpace() const {
return isl_map_get_space(AccessRelation);
}
__isl_give isl_map *MemoryAccess::getNewAccessRelation() const {
return isl_map_copy(NewAccessRelation);
}
std::string MemoryAccess::getNewAccessRelationStr() const {
return stringFromIslObj(NewAccessRelation);
}
__isl_give isl_basic_map *
MemoryAccess::createBasicAccessMap(ScopStmt *Statement) {
isl_space *Space = isl_space_set_alloc(Statement->getIslCtx(), 0, 1);
Space = isl_space_align_params(Space, Statement->getDomainSpace());
return isl_basic_map_from_domain_and_range(
isl_basic_set_universe(Statement->getDomainSpace()),
isl_basic_set_universe(Space));
}
// Formalize no out-of-bound access assumption
//
// When delinearizing array accesses we optimistically assume that the
// delinearized accesses do not access out of bound locations (the subscript
// expression of each array evaluates for each statement instance that is
// executed to a value that is larger than zero and strictly smaller than the
// size of the corresponding dimension). The only exception is the outermost
// dimension for which we do not need to assume any upper bound. At this point
// we formalize this assumption to ensure that at code generation time the
// relevant run-time checks can be generated.
//
// To find the set of constraints necessary to avoid out of bound accesses, we
// first build the set of data locations that are not within array bounds. We
// then apply the reverse access relation to obtain the set of iterations that
// may contain invalid accesses and reduce this set of iterations to the ones
// that are actually executed by intersecting them with the domain of the
// statement. If we now project out all loop dimensions, we obtain a set of
// parameters that may cause statement instances to be executed that may
// possibly yield out of bound memory accesses. The complement of these
// constraints is the set of constraints that needs to be assumed to ensure such
// statement instances are never executed.
void MemoryAccess::assumeNoOutOfBound() {
isl_space *Space = isl_space_range(getOriginalAccessRelationSpace());
isl_set *Outside = isl_set_empty(isl_space_copy(Space));
for (int i = 1, Size = isl_space_dim(Space, isl_dim_set); i < Size; ++i) {
isl_local_space *LS = isl_local_space_from_space(isl_space_copy(Space));
isl_pw_aff *Var =
isl_pw_aff_var_on_domain(isl_local_space_copy(LS), isl_dim_set, i);
isl_pw_aff *Zero = isl_pw_aff_zero_on_domain(LS);
isl_set *DimOutside;
DimOutside = isl_pw_aff_lt_set(isl_pw_aff_copy(Var), Zero);
isl_pw_aff *SizeE = getScopArrayInfo()->getDimensionSizePw(i);
SizeE = isl_pw_aff_add_dims(SizeE, isl_dim_in,
isl_space_dim(Space, isl_dim_set));
SizeE = isl_pw_aff_set_tuple_id(SizeE, isl_dim_in,
isl_space_get_tuple_id(Space, isl_dim_set));
DimOutside = isl_set_union(DimOutside, isl_pw_aff_le_set(SizeE, Var));
Outside = isl_set_union(Outside, DimOutside);
}
Outside = isl_set_apply(Outside, isl_map_reverse(getAccessRelation()));
Outside = isl_set_intersect(Outside, Statement->getDomain());
Outside = isl_set_params(Outside);
// Remove divs to avoid the construction of overly complicated assumptions.
// Doing so increases the set of parameter combinations that are assumed to
// not appear. This is always save, but may make the resulting run-time check
// bail out more often than strictly necessary.
Outside = isl_set_remove_divs(Outside);
Outside = isl_set_complement(Outside);
Statement->getParent()->addAssumption(INBOUNDS, Outside,
getAccessInstruction()->getDebugLoc());
isl_space_free(Space);
}
void MemoryAccess::computeBoundsOnAccessRelation(unsigned ElementSize) {
ScalarEvolution *SE = Statement->getParent()->getSE();
Value *Ptr = getPointerOperand(*getAccessInstruction());
if (!Ptr || !SE->isSCEVable(Ptr->getType()))
return;
auto *PtrSCEV = SE->getSCEV(Ptr);
if (isa<SCEVCouldNotCompute>(PtrSCEV))
return;
auto *BasePtrSCEV = SE->getPointerBase(PtrSCEV);
if (BasePtrSCEV && !isa<SCEVCouldNotCompute>(BasePtrSCEV))
PtrSCEV = SE->getMinusSCEV(PtrSCEV, BasePtrSCEV);
const ConstantRange &Range = SE->getSignedRange(PtrSCEV);
if (Range.isFullSet())
return;
bool isWrapping = Range.isSignWrappedSet();
unsigned BW = Range.getBitWidth();
const auto LB = isWrapping ? Range.getLower() : Range.getSignedMin();
const auto UB = isWrapping ? Range.getUpper() : Range.getSignedMax();
auto Min = LB.sdiv(APInt(BW, ElementSize));
auto Max = (UB - APInt(BW, 1)).sdiv(APInt(BW, ElementSize));
isl_set *AccessRange = isl_map_range(isl_map_copy(AccessRelation));
AccessRange =
addRangeBoundsToSet(AccessRange, ConstantRange(Min, Max), 0, isl_dim_set);
AccessRelation = isl_map_intersect_range(AccessRelation, AccessRange);
}
__isl_give isl_map *MemoryAccess::foldAccess(__isl_take isl_map *AccessRelation,
ScopStmt *Statement) {
int Size = Subscripts.size();
for (int i = Size - 2; i >= 0; --i) {
isl_space *Space;
isl_map *MapOne, *MapTwo;
isl_pw_aff *DimSize = Statement->getPwAff(Sizes[i]);
isl_space *SpaceSize = isl_pw_aff_get_space(DimSize);
isl_pw_aff_free(DimSize);
isl_id *ParamId = isl_space_get_dim_id(SpaceSize, isl_dim_param, 0);
Space = isl_map_get_space(AccessRelation);
Space = isl_space_map_from_set(isl_space_range(Space));
Space = isl_space_align_params(Space, SpaceSize);
int ParamLocation = isl_space_find_dim_by_id(Space, isl_dim_param, ParamId);
isl_id_free(ParamId);
MapOne = isl_map_universe(isl_space_copy(Space));
for (int j = 0; j < Size; ++j)
MapOne = isl_map_equate(MapOne, isl_dim_in, j, isl_dim_out, j);
MapOne = isl_map_lower_bound_si(MapOne, isl_dim_in, i + 1, 0);
MapTwo = isl_map_universe(isl_space_copy(Space));
for (int j = 0; j < Size; ++j)
if (j < i || j > i + 1)
MapTwo = isl_map_equate(MapTwo, isl_dim_in, j, isl_dim_out, j);
isl_local_space *LS = isl_local_space_from_space(Space);
isl_constraint *C;
C = isl_equality_alloc(isl_local_space_copy(LS));
C = isl_constraint_set_constant_si(C, -1);
C = isl_constraint_set_coefficient_si(C, isl_dim_in, i, 1);
C = isl_constraint_set_coefficient_si(C, isl_dim_out, i, -1);
MapTwo = isl_map_add_constraint(MapTwo, C);
C = isl_equality_alloc(LS);
C = isl_constraint_set_coefficient_si(C, isl_dim_in, i + 1, 1);
C = isl_constraint_set_coefficient_si(C, isl_dim_out, i + 1, -1);
C = isl_constraint_set_coefficient_si(C, isl_dim_param, ParamLocation, 1);
MapTwo = isl_map_add_constraint(MapTwo, C);
MapTwo = isl_map_upper_bound_si(MapTwo, isl_dim_in, i + 1, -1);
MapOne = isl_map_union(MapOne, MapTwo);
AccessRelation = isl_map_apply_range(AccessRelation, MapOne);
}
return AccessRelation;
}
/// @brief Check if @p Expr is divisible by @p Size.
static bool isDivisible(const SCEV *Expr, unsigned Size, ScalarEvolution &SE) {
// Only one factor needs to be divisible.
if (auto *MulExpr = dyn_cast<SCEVMulExpr>(Expr)) {
for (auto *FactorExpr : MulExpr->operands())
if (isDivisible(FactorExpr, Size, SE))
return true;
return false;
}
// For other n-ary expressions (Add, AddRec, Max,...) all operands need
// to be divisble.
if (auto *NAryExpr = dyn_cast<SCEVNAryExpr>(Expr)) {
for (auto *OpExpr : NAryExpr->operands())
if (!isDivisible(OpExpr, Size, SE))
return false;
return true;
}
auto *SizeSCEV = SE.getConstant(Expr->getType(), Size);
auto *UDivSCEV = SE.getUDivExpr(Expr, SizeSCEV);
auto *MulSCEV = SE.getMulExpr(UDivSCEV, SizeSCEV);
return MulSCEV == Expr;
}
void MemoryAccess::buildAccessRelation(const ScopArrayInfo *SAI) {
assert(!AccessRelation && "AccessReltation already built");
isl_ctx *Ctx = isl_id_get_ctx(Id);
isl_id *BaseAddrId = SAI->getBasePtrId();
if (!isAffine()) {
// We overapproximate non-affine accesses with a possible access to the
// whole array. For read accesses it does not make a difference, if an
// access must or may happen. However, for write accesses it is important to
// differentiate between writes that must happen and writes that may happen.
AccessRelation = isl_map_from_basic_map(createBasicAccessMap(Statement));
AccessRelation =
isl_map_set_tuple_id(AccessRelation, isl_dim_out, BaseAddrId);
computeBoundsOnAccessRelation(getElemSizeInBytes());
return;
}
Scop &S = *getStatement()->getParent();
isl_space *Space = isl_space_alloc(Ctx, 0, Statement->getNumIterators(), 0);
AccessRelation = isl_map_universe(Space);
for (int i = 0, Size = Subscripts.size(); i < Size; ++i) {
isl_pw_aff *Affine = Statement->getPwAff(Subscripts[i]);
if (Size == 1) {
// For the non delinearized arrays, divide the access function of the last
// subscript by the size of the elements in the array.
//
// A stride one array access in C expressed as A[i] is expressed in
// LLVM-IR as something like A[i * elementsize]. This hides the fact that
// two subsequent values of 'i' index two values that are stored next to
// each other in memory. By this division we make this characteristic
// obvious again. However, if the index is not divisible by the element
// size we will bail out.
isl_val *v = isl_val_int_from_si(Ctx, getElemSizeInBytes());
Affine = isl_pw_aff_scale_down_val(Affine, v);
if (!isDivisible(Subscripts[0], getElemSizeInBytes(), *S.getSE()))
S.invalidate(ALIGNMENT, AccessInstruction->getDebugLoc());
}
isl_map *SubscriptMap = isl_map_from_pw_aff(Affine);
AccessRelation = isl_map_flat_range_product(AccessRelation, SubscriptMap);
}
if (Sizes.size() > 1 && !isa<SCEVConstant>(Sizes[0]))
AccessRelation = foldAccess(AccessRelation, Statement);
Space = Statement->getDomainSpace();
AccessRelation = isl_map_set_tuple_id(
AccessRelation, isl_dim_in, isl_space_get_tuple_id(Space, isl_dim_set));
AccessRelation =
isl_map_set_tuple_id(AccessRelation, isl_dim_out, BaseAddrId);
AccessRelation = isl_map_gist_domain(AccessRelation, Statement->getDomain());
isl_space_free(Space);
}
MemoryAccess::MemoryAccess(ScopStmt *Stmt, Instruction *AccessInst,
AccessType Type, Value *BaseAddress,
unsigned ElemBytes, bool Affine,
ArrayRef<const SCEV *> Subscripts,
ArrayRef<const SCEV *> Sizes, Value *AccessValue,
ScopArrayInfo::MemoryKind Kind, StringRef BaseName)
: Kind(Kind), AccType(Type), RedType(RT_NONE), Statement(Stmt),
BaseAddr(BaseAddress), BaseName(BaseName), ElemBytes(ElemBytes),
Sizes(Sizes.begin(), Sizes.end()), AccessInstruction(AccessInst),
AccessValue(AccessValue), IsAffine(Affine),
Subscripts(Subscripts.begin(), Subscripts.end()), AccessRelation(nullptr),
NewAccessRelation(nullptr) {
std::string IdName = "__polly_array_ref";
Id = isl_id_alloc(Stmt->getParent()->getIslCtx(), IdName.c_str(), this);
}
void MemoryAccess::realignParams() {
isl_space *ParamSpace = Statement->getParent()->getParamSpace();
AccessRelation = isl_map_align_params(AccessRelation, ParamSpace);
}
const std::string MemoryAccess::getReductionOperatorStr() const {
return MemoryAccess::getReductionOperatorStr(getReductionType());
}
__isl_give isl_id *MemoryAccess::getId() const { return isl_id_copy(Id); }
raw_ostream &polly::operator<<(raw_ostream &OS,
MemoryAccess::ReductionType RT) {
if (RT == MemoryAccess::RT_NONE)
OS << "NONE";
else
OS << MemoryAccess::getReductionOperatorStr(RT);
return OS;
}
void MemoryAccess::print(raw_ostream &OS) const {
switch (AccType) {
case READ:
OS.indent(12) << "ReadAccess :=\t";
break;
case MUST_WRITE:
OS.indent(12) << "MustWriteAccess :=\t";
break;
case MAY_WRITE:
OS.indent(12) << "MayWriteAccess :=\t";
break;
}
OS << "[Reduction Type: " << getReductionType() << "] ";
OS << "[Scalar: " << isScalarKind() << "]\n";
OS.indent(16) << getOriginalAccessRelationStr() << ";\n";
if (hasNewAccessRelation())
OS.indent(11) << "new: " << getNewAccessRelationStr() << ";\n";
}
void MemoryAccess::dump() const { print(errs()); }
// Create a map in the size of the provided set domain, that maps from the
// one element of the provided set domain to another element of the provided
// set domain.
// The mapping is limited to all points that are equal in all but the last
// dimension and for which the last dimension of the input is strict smaller
// than the last dimension of the output.
//
// getEqualAndLarger(set[i0, i1, ..., iX]):
//
// set[i0, i1, ..., iX] -> set[o0, o1, ..., oX]
// : i0 = o0, i1 = o1, ..., i(X-1) = o(X-1), iX < oX
//
static isl_map *getEqualAndLarger(isl_space *setDomain) {
isl_space *Space = isl_space_map_from_set(setDomain);
isl_map *Map = isl_map_universe(Space);
unsigned lastDimension = isl_map_dim(Map, isl_dim_in) - 1;
// Set all but the last dimension to be equal for the input and output
//
// input[i0, i1, ..., iX] -> output[o0, o1, ..., oX]
// : i0 = o0, i1 = o1, ..., i(X-1) = o(X-1)
for (unsigned i = 0; i < lastDimension; ++i)
Map = isl_map_equate(Map, isl_dim_in, i, isl_dim_out, i);
// Set the last dimension of the input to be strict smaller than the
// last dimension of the output.
//
// input[?,?,?,...,iX] -> output[?,?,?,...,oX] : iX < oX
Map = isl_map_order_lt(Map, isl_dim_in, lastDimension, isl_dim_out,
lastDimension);
return Map;
}
__isl_give isl_set *
MemoryAccess::getStride(__isl_take const isl_map *Schedule) const {
isl_map *S = const_cast<isl_map *>(Schedule);
isl_map *AccessRelation = getAccessRelation();
isl_space *Space = isl_space_range(isl_map_get_space(S));
isl_map *NextScatt = getEqualAndLarger(Space);
S = isl_map_reverse(S);
NextScatt = isl_map_lexmin(NextScatt);
NextScatt = isl_map_apply_range(NextScatt, isl_map_copy(S));
NextScatt = isl_map_apply_range(NextScatt, isl_map_copy(AccessRelation));
NextScatt = isl_map_apply_domain(NextScatt, S);
NextScatt = isl_map_apply_domain(NextScatt, AccessRelation);
isl_set *Deltas = isl_map_deltas(NextScatt);
return Deltas;
}
bool MemoryAccess::isStrideX(__isl_take const isl_map *Schedule,
int StrideWidth) const {
isl_set *Stride, *StrideX;
bool IsStrideX;
Stride = getStride(Schedule);
StrideX = isl_set_universe(isl_set_get_space(Stride));
for (unsigned i = 0; i < isl_set_dim(StrideX, isl_dim_set) - 1; i++)
StrideX = isl_set_fix_si(StrideX, isl_dim_set, i, 0);
StrideX = isl_set_fix_si(StrideX, isl_dim_set,
isl_set_dim(StrideX, isl_dim_set) - 1, StrideWidth);
IsStrideX = isl_set_is_subset(Stride, StrideX);
isl_set_free(StrideX);
isl_set_free(Stride);
return IsStrideX;
}
bool MemoryAccess::isStrideZero(const isl_map *Schedule) const {
return isStrideX(Schedule, 0);
}
bool MemoryAccess::isStrideOne(const isl_map *Schedule) const {
return isStrideX(Schedule, 1);
}
void MemoryAccess::setNewAccessRelation(isl_map *NewAccess) {
isl_map_free(NewAccessRelation);
NewAccessRelation = NewAccess;
}
//===----------------------------------------------------------------------===//
isl_map *ScopStmt::getSchedule() const {
isl_set *Domain = getDomain();
if (isl_set_is_empty(Domain)) {
isl_set_free(Domain);
return isl_map_from_aff(
isl_aff_zero_on_domain(isl_local_space_from_space(getDomainSpace())));
}
auto *Schedule = getParent()->getSchedule();
Schedule = isl_union_map_intersect_domain(
Schedule, isl_union_set_from_set(isl_set_copy(Domain)));
if (isl_union_map_is_empty(Schedule)) {
isl_set_free(Domain);
isl_union_map_free(Schedule);
return isl_map_from_aff(
isl_aff_zero_on_domain(isl_local_space_from_space(getDomainSpace())));
}
auto *M = isl_map_from_union_map(Schedule);
M = isl_map_coalesce(M);
M = isl_map_gist_domain(M, Domain);
M = isl_map_coalesce(M);
return M;
}
__isl_give isl_pw_aff *ScopStmt::getPwAff(const SCEV *E) {
return getParent()->getPwAff(E, isBlockStmt() ? getBasicBlock()
: getRegion()->getEntry());
}
void ScopStmt::restrictDomain(__isl_take isl_set *NewDomain) {
assert(isl_set_is_subset(NewDomain, Domain) &&
"New domain is not a subset of old domain!");
isl_set_free(Domain);
Domain = NewDomain;
}
void ScopStmt::buildAccessRelations() {
for (MemoryAccess *Access : MemAccs) {
Type *ElementType = Access->getAccessValue()->getType();
ScopArrayInfo::MemoryKind Ty;
if (Access->isPHIKind())
Ty = ScopArrayInfo::MK_PHI;
else if (Access->isExitPHIKind())
Ty = ScopArrayInfo::MK_ExitPHI;
else if (Access->isValueKind())
Ty = ScopArrayInfo::MK_Value;
else
Ty = ScopArrayInfo::MK_Array;
const ScopArrayInfo *SAI = getParent()->getOrCreateScopArrayInfo(
Access->getBaseAddr(), ElementType, Access->Sizes, Ty);
Access->buildAccessRelation(SAI);
}
}
void ScopStmt::addAccess(MemoryAccess *Access) {
Instruction *AccessInst = Access->getAccessInstruction();
if (Access->isArrayKind()) {
MemoryAccessList &MAL = InstructionToAccess[AccessInst];
MAL.emplace_front(Access);
}
MemAccs.push_back(Access);
}
void ScopStmt::realignParams() {
for (MemoryAccess *MA : *this)
MA->realignParams();
Domain = isl_set_align_params(Domain, Parent.getParamSpace());
}
/// @brief Add @p BSet to the set @p User if @p BSet is bounded.
static isl_stat collectBoundedParts(__isl_take isl_basic_set *BSet,
void *User) {
isl_set **BoundedParts = static_cast<isl_set **>(User);
if (isl_basic_set_is_bounded(BSet))
*BoundedParts = isl_set_union(*BoundedParts, isl_set_from_basic_set(BSet));
else
isl_basic_set_free(BSet);
return isl_stat_ok;
}
/// @brief Return the bounded parts of @p S.
static __isl_give isl_set *collectBoundedParts(__isl_take isl_set *S) {
isl_set *BoundedParts = isl_set_empty(isl_set_get_space(S));
isl_set_foreach_basic_set(S, collectBoundedParts, &BoundedParts);
isl_set_free(S);
return BoundedParts;
}
/// @brief Compute the (un)bounded parts of @p S wrt. to dimension @p Dim.
///
/// @returns A separation of @p S into first an unbounded then a bounded subset,
/// both with regards to the dimension @p Dim.
static std::pair<__isl_give isl_set *, __isl_give isl_set *>
partitionSetParts(__isl_take isl_set *S, unsigned Dim) {
for (unsigned u = 0, e = isl_set_n_dim(S); u < e; u++)
S = isl_set_lower_bound_si(S, isl_dim_set, u, 0);
unsigned NumDimsS = isl_set_n_dim(S);
isl_set *OnlyDimS = isl_set_copy(S);
// Remove dimensions that are greater than Dim as they are not interesting.
assert(NumDimsS >= Dim + 1);
OnlyDimS =
isl_set_project_out(OnlyDimS, isl_dim_set, Dim + 1, NumDimsS - Dim - 1);
// Create artificial parametric upper bounds for dimensions smaller than Dim
// as we are not interested in them.
OnlyDimS = isl_set_insert_dims(OnlyDimS, isl_dim_param, 0, Dim);
for (unsigned u = 0; u < Dim; u++) {
isl_constraint *C = isl_inequality_alloc(
isl_local_space_from_space(isl_set_get_space(OnlyDimS)));
C = isl_constraint_set_coefficient_si(C, isl_dim_param, u, 1);
C = isl_constraint_set_coefficient_si(C, isl_dim_set, u, -1);
OnlyDimS = isl_set_add_constraint(OnlyDimS, C);
}
// Collect all bounded parts of OnlyDimS.
isl_set *BoundedParts = collectBoundedParts(OnlyDimS);
// Create the dimensions greater than Dim again.
BoundedParts = isl_set_insert_dims(BoundedParts, isl_dim_set, Dim + 1,
NumDimsS - Dim - 1);
// Remove the artificial upper bound parameters again.
BoundedParts = isl_set_remove_dims(BoundedParts, isl_dim_param, 0, Dim);
isl_set *UnboundedParts = isl_set_subtract(S, isl_set_copy(BoundedParts));
return std::make_pair(UnboundedParts, BoundedParts);
}
/// @brief Set the dimension Ids from @p From in @p To.
static __isl_give isl_set *setDimensionIds(__isl_keep isl_set *From,
__isl_take isl_set *To) {
for (unsigned u = 0, e = isl_set_n_dim(From); u < e; u++) {
isl_id *DimId = isl_set_get_dim_id(From, isl_dim_set, u);
To = isl_set_set_dim_id(To, isl_dim_set, u, DimId);
}
return To;
}
/// @brief Create the conditions under which @p L @p Pred @p R is true.
static __isl_give isl_set *buildConditionSet(ICmpInst::Predicate Pred,
__isl_take isl_pw_aff *L,
__isl_take isl_pw_aff *R) {
switch (Pred) {
case ICmpInst::ICMP_EQ:
return isl_pw_aff_eq_set(L, R);
case ICmpInst::ICMP_NE:
return isl_pw_aff_ne_set(L, R);
case ICmpInst::ICMP_SLT:
return isl_pw_aff_lt_set(L, R);
case ICmpInst::ICMP_SLE:
return isl_pw_aff_le_set(L, R);
case ICmpInst::ICMP_SGT:
return isl_pw_aff_gt_set(L, R);
case ICmpInst::ICMP_SGE:
return isl_pw_aff_ge_set(L, R);
case ICmpInst::ICMP_ULT:
return isl_pw_aff_lt_set(L, R);
case ICmpInst::ICMP_UGT:
return isl_pw_aff_gt_set(L, R);
case ICmpInst::ICMP_ULE:
return isl_pw_aff_le_set(L, R);
case ICmpInst::ICMP_UGE:
return isl_pw_aff_ge_set(L, R);
default:
llvm_unreachable("Non integer predicate not supported");
}
}
/// @brief Create the conditions under which @p L @p Pred @p R is true.
///
/// Helper function that will make sure the dimensions of the result have the
/// same isl_id's as the @p Domain.
static __isl_give isl_set *buildConditionSet(ICmpInst::Predicate Pred,
__isl_take isl_pw_aff *L,
__isl_take isl_pw_aff *R,
__isl_keep isl_set *Domain) {
isl_set *ConsequenceCondSet = buildConditionSet(Pred, L, R);
return setDimensionIds(Domain, ConsequenceCondSet);
}
/// @brief Build the conditions sets for the switch @p SI in the @p Domain.
///
/// This will fill @p ConditionSets with the conditions under which control
/// will be moved from @p SI to its successors. Hence, @p ConditionSets will
/// have as many elements as @p SI has successors.
static void
buildConditionSets(Scop &S, SwitchInst *SI, Loop *L, __isl_keep isl_set *Domain,
SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
Value *Condition = getConditionFromTerminator(SI);
assert(Condition && "No condition for switch");
ScalarEvolution &SE = *S.getSE();
BasicBlock *BB = SI->getParent();
isl_pw_aff *LHS, *RHS;
LHS = S.getPwAff(SE.getSCEVAtScope(Condition, L), BB);
unsigned NumSuccessors = SI->getNumSuccessors();
ConditionSets.resize(NumSuccessors);
for (auto &Case : SI->cases()) {
unsigned Idx = Case.getSuccessorIndex();
ConstantInt *CaseValue = Case.getCaseValue();
RHS = S.getPwAff(SE.getSCEV(CaseValue), BB);
isl_set *CaseConditionSet =
buildConditionSet(ICmpInst::ICMP_EQ, isl_pw_aff_copy(LHS), RHS, Domain);
ConditionSets[Idx] = isl_set_coalesce(
isl_set_intersect(CaseConditionSet, isl_set_copy(Domain)));
}
assert(ConditionSets[0] == nullptr && "Default condition set was set");
isl_set *ConditionSetUnion = isl_set_copy(ConditionSets[1]);
for (unsigned u = 2; u < NumSuccessors; u++)
ConditionSetUnion =
isl_set_union(ConditionSetUnion, isl_set_copy(ConditionSets[u]));
ConditionSets[0] = setDimensionIds(
Domain, isl_set_subtract(isl_set_copy(Domain), ConditionSetUnion));
S.markAsOptimized();
isl_pw_aff_free(LHS);
}
/// @brief Build the conditions sets for the branch condition @p Condition in
/// the @p Domain.
///
/// This will fill @p ConditionSets with the conditions under which control
/// will be moved from @p TI to its successors. Hence, @p ConditionSets will
/// have as many elements as @p TI has successors. If @p TI is nullptr the
/// context under which @p Condition is true/false will be returned as the
/// new elements of @p ConditionSets.
static void
buildConditionSets(Scop &S, Value *Condition, TerminatorInst *TI, Loop *L,
__isl_keep isl_set *Domain,
SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
isl_set *ConsequenceCondSet = nullptr;
if (auto *CCond = dyn_cast<ConstantInt>(Condition)) {
if (CCond->isZero())
ConsequenceCondSet = isl_set_empty(isl_set_get_space(Domain));
else
ConsequenceCondSet = isl_set_universe(isl_set_get_space(Domain));
} else if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Condition)) {
auto Opcode = BinOp->getOpcode();
assert(Opcode == Instruction::And || Opcode == Instruction::Or);
buildConditionSets(S, BinOp->getOperand(0), TI, L, Domain, ConditionSets);
buildConditionSets(S, BinOp->getOperand(1), TI, L, Domain, ConditionSets);
isl_set_free(ConditionSets.pop_back_val());
isl_set *ConsCondPart0 = ConditionSets.pop_back_val();
isl_set_free(ConditionSets.pop_back_val());
isl_set *ConsCondPart1 = ConditionSets.pop_back_val();
if (Opcode == Instruction::And)
ConsequenceCondSet = isl_set_intersect(ConsCondPart0, ConsCondPart1);
else
ConsequenceCondSet = isl_set_union(ConsCondPart0, ConsCondPart1);
} else {
auto *ICond = dyn_cast<ICmpInst>(Condition);
assert(ICond &&
"Condition of exiting branch was neither constant nor ICmp!");
ScalarEvolution &SE = *S.getSE();
BasicBlock *BB = TI ? TI->getParent() : nullptr;
isl_pw_aff *LHS, *RHS;
LHS = S.getPwAff(SE.getSCEVAtScope(ICond->getOperand(0), L), BB);
RHS = S.getPwAff(SE.getSCEVAtScope(ICond->getOperand(1), L), BB);
ConsequenceCondSet =
buildConditionSet(ICond->getPredicate(), LHS, RHS, Domain);
}
// If no terminator was given we are only looking for parameter constraints
// under which @p Condition is true/false.
if (!TI)
ConsequenceCondSet = isl_set_params(ConsequenceCondSet);
assert(ConsequenceCondSet);
isl_set *AlternativeCondSet =
isl_set_complement(isl_set_copy(ConsequenceCondSet));
ConditionSets.push_back(isl_set_coalesce(
isl_set_intersect(ConsequenceCondSet, isl_set_copy(Domain))));
ConditionSets.push_back(isl_set_coalesce(
isl_set_intersect(AlternativeCondSet, isl_set_copy(Domain))));
}
/// @brief Build the conditions sets for the terminator @p TI in the @p Domain.
///
/// This will fill @p ConditionSets with the conditions under which control
/// will be moved from @p TI to its successors. Hence, @p ConditionSets will
/// have as many elements as @p TI has successors.
static void
buildConditionSets(Scop &S, TerminatorInst *TI, Loop *L,
__isl_keep isl_set *Domain,
SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
if (SwitchInst *SI = dyn_cast<SwitchInst>(TI))
return buildConditionSets(S, SI, L, Domain, ConditionSets);
assert(isa<BranchInst>(TI) && "Terminator was neither branch nor switch.");
if (TI->getNumSuccessors() == 1) {
ConditionSets.push_back(isl_set_copy(Domain));
return;
}
Value *Condition = getConditionFromTerminator(TI);
assert(Condition && "No condition for Terminator");
return buildConditionSets(S, Condition, TI, L, Domain, ConditionSets);
}
void ScopStmt::buildDomain() {
isl_id *Id;
Id = isl_id_alloc(getIslCtx(), getBaseName(), this);
Domain = getParent()->getDomainConditions(this);
Domain = isl_set_set_tuple_id(Domain, Id);
}
void ScopStmt::deriveAssumptionsFromGEP(GetElementPtrInst *GEP) {
isl_ctx *Ctx = Parent.getIslCtx();
isl_local_space *LSpace = isl_local_space_from_space(getDomainSpace());
Type *Ty = GEP->getPointerOperandType();
ScalarEvolution &SE = *Parent.getSE();
ScopDetection &SD = Parent.getSD();
// The set of loads that are required to be invariant.
auto &ScopRIL = *SD.getRequiredInvariantLoads(&Parent.getRegion());
std::vector<const SCEV *> Subscripts;
std::vector<int> Sizes;
std::tie(Subscripts, Sizes) = getIndexExpressionsFromGEP(GEP, SE);
if (auto *PtrTy = dyn_cast<PointerType>(Ty)) {
Ty = PtrTy->getElementType();
}
int IndexOffset = Subscripts.size() - Sizes.size();
assert(IndexOffset <= 1 && "Unexpected large index offset");
for (size_t i = 0; i < Sizes.size(); i++) {
auto Expr = Subscripts[i + IndexOffset];
auto Size = Sizes[i];
InvariantLoadsSetTy AccessILS;
if (!isAffineExpr(&Parent.getRegion(), Expr, SE, nullptr, &AccessILS))
continue;
bool NonAffine = false;
for (LoadInst *LInst : AccessILS)
if (!ScopRIL.count(LInst))
NonAffine = true;
if (NonAffine)
continue;
isl_pw_aff *AccessOffset = getPwAff(Expr);
AccessOffset =
isl_pw_aff_set_tuple_id(AccessOffset, isl_dim_in, getDomainId());
isl_pw_aff *DimSize = isl_pw_aff_from_aff(isl_aff_val_on_domain(
isl_local_space_copy(LSpace), isl_val_int_from_si(Ctx, Size)));
isl_set *OutOfBound = isl_pw_aff_ge_set(AccessOffset, DimSize);
OutOfBound = isl_set_intersect(getDomain(), OutOfBound);
OutOfBound = isl_set_params(OutOfBound);
isl_set *InBound = isl_set_complement(OutOfBound);
isl_set *Executed = isl_set_params(getDomain());
// A => B == !A or B
isl_set *InBoundIfExecuted =
isl_set_union(isl_set_complement(Executed), InBound);
InBoundIfExecuted = isl_set_coalesce(InBoundIfExecuted);
Parent.addAssumption(INBOUNDS, InBoundIfExecuted, GEP->getDebugLoc());
}
isl_local_space_free(LSpace);
}
void ScopStmt::deriveAssumptions(BasicBlock *Block) {
for (Instruction &Inst : *Block)
if (auto *GEP = dyn_cast<GetElementPtrInst>(&Inst))
deriveAssumptionsFromGEP(GEP);
}
void ScopStmt::collectSurroundingLoops() {
for (unsigned u = 0, e = isl_set_n_dim(Domain); u < e; u++) {
isl_id *DimId = isl_set_get_dim_id(Domain, isl_dim_set, u);
NestLoops.push_back(static_cast<Loop *>(isl_id_get_user(DimId)));
isl_id_free(DimId);
}
}
ScopStmt::ScopStmt(Scop &parent, Region &R)
: Parent(parent), Domain(nullptr), BB(nullptr), R(&R), Build(nullptr) {
BaseName = getIslCompatibleName("Stmt_", R.getNameStr(), "");
}
ScopStmt::ScopStmt(Scop &parent, BasicBlock &bb)
: Parent(parent), Domain(nullptr), BB(&bb), R(nullptr), Build(nullptr) {
BaseName = getIslCompatibleName("Stmt_", &bb, "");
}
void ScopStmt::init() {
assert(!Domain && "init must be called only once");
buildDomain();
collectSurroundingLoops();
buildAccessRelations();
if (BB) {
deriveAssumptions(BB);
} else {
for (BasicBlock *Block : R->blocks()) {
deriveAssumptions(Block);
}
}
if (DetectReductions)
checkForReductions();
}
/// @brief Collect loads which might form a reduction chain with @p StoreMA
///
/// Check if the stored value for @p StoreMA is a binary operator with one or
/// two loads as operands. If the binary operand is commutative & associative,
/// used only once (by @p StoreMA) and its load operands are also used only
/// once, we have found a possible reduction chain. It starts at an operand
/// load and includes the binary operator and @p StoreMA.
///
/// Note: We allow only one use to ensure the load and binary operator cannot
/// escape this block or into any other store except @p StoreMA.
void ScopStmt::collectCandiateReductionLoads(
MemoryAccess *StoreMA, SmallVectorImpl<MemoryAccess *> &Loads) {
auto *Store = dyn_cast<StoreInst>(StoreMA->getAccessInstruction());
if (!Store)
return;
// Skip if there is not one binary operator between the load and the store
auto *BinOp = dyn_cast<BinaryOperator>(Store->getValueOperand());
if (!BinOp)
return;
// Skip if the binary operators has multiple uses
if (BinOp->getNumUses() != 1)
return;
// Skip if the opcode of the binary operator is not commutative/associative
if (!BinOp->isCommutative() || !BinOp->isAssociative())
return;
// Skip if the binary operator is outside the current SCoP
if (BinOp->getParent() != Store->getParent())
return;
// Skip if it is a multiplicative reduction and we disabled them
if (DisableMultiplicativeReductions &&
(BinOp->getOpcode() == Instruction::Mul ||
BinOp->getOpcode() == Instruction::FMul))
return;
// Check the binary operator operands for a candidate load
auto *PossibleLoad0 = dyn_cast<LoadInst>(BinOp->getOperand(0));
auto *PossibleLoad1 = dyn_cast<LoadInst>(BinOp->getOperand(1));
if (!PossibleLoad0 && !PossibleLoad1)
return;
// A load is only a candidate if it cannot escape (thus has only this use)
if (PossibleLoad0 && PossibleLoad0->getNumUses() == 1)
if (PossibleLoad0->getParent() == Store->getParent())
Loads.push_back(&getArrayAccessFor(PossibleLoad0));
if (PossibleLoad1 && PossibleLoad1->getNumUses() == 1)
if (PossibleLoad1->getParent() == Store->getParent())
Loads.push_back(&getArrayAccessFor(PossibleLoad1));
}
/// @brief Check for reductions in this ScopStmt
///
/// Iterate over all store memory accesses and check for valid binary reduction
/// like chains. For all candidates we check if they have the same base address
/// and there are no other accesses which overlap with them. The base address
/// check rules out impossible reductions candidates early. The overlap check,
/// together with the "only one user" check in collectCandiateReductionLoads,
/// guarantees that none of the intermediate results will escape during
/// execution of the loop nest. We basically check here that no other memory
/// access can access the same memory as the potential reduction.
void ScopStmt::checkForReductions() {
SmallVector<MemoryAccess *, 2> Loads;
SmallVector<std::pair<MemoryAccess *, MemoryAccess *>, 4> Candidates;
// First collect candidate load-store reduction chains by iterating over all
// stores and collecting possible reduction loads.
for (MemoryAccess *StoreMA : MemAccs) {
if (StoreMA->isRead())
continue;
Loads.clear();
collectCandiateReductionLoads(StoreMA, Loads);
for (MemoryAccess *LoadMA : Loads)
Candidates.push_back(std::make_pair(LoadMA, StoreMA));
}
// Then check each possible candidate pair.
for (const auto &CandidatePair : Candidates) {
bool Valid = true;
isl_map *LoadAccs = CandidatePair.first->getAccessRelation();
isl_map *StoreAccs = CandidatePair.second->getAccessRelation();
// Skip those with obviously unequal base addresses.
if (!isl_map_has_equal_space(LoadAccs, StoreAccs)) {
isl_map_free(LoadAccs);
isl_map_free(StoreAccs);
continue;
}
// And check if the remaining for overlap with other memory accesses.
isl_map *AllAccsRel = isl_map_union(LoadAccs, StoreAccs);
AllAccsRel = isl_map_intersect_domain(AllAccsRel, getDomain());
isl_set *AllAccs = isl_map_range(AllAccsRel);
for (MemoryAccess *MA : MemAccs) {
if (MA == CandidatePair.first || MA == CandidatePair.second)
continue;
isl_map *AccRel =
isl_map_intersect_domain(MA->getAccessRelation(), getDomain());
isl_set *Accs = isl_map_range(AccRel);
if (isl_set_has_equal_space(AllAccs, Accs) || isl_set_free(Accs)) {
isl_set *OverlapAccs = isl_set_intersect(Accs, isl_set_copy(AllAccs));
Valid = Valid && isl_set_is_empty(OverlapAccs);
isl_set_free(OverlapAccs);
}
}
isl_set_free(AllAccs);
if (!Valid)
continue;
const LoadInst *Load =
dyn_cast<const LoadInst>(CandidatePair.first->getAccessInstruction());
MemoryAccess::ReductionType RT =
getReductionType(dyn_cast<BinaryOperator>(Load->user_back()), Load);
// If no overlapping access was found we mark the load and store as
// reduction like.
CandidatePair.first->markAsReductionLike(RT);
CandidatePair.second->markAsReductionLike(RT);
}
}
std::string ScopStmt::getDomainStr() const { return stringFromIslObj(Domain); }
std::string ScopStmt::getScheduleStr() const {
auto *S = getSchedule();
auto Str = stringFromIslObj(S);
isl_map_free(S);
return Str;
}
unsigned ScopStmt::getNumParams() const { return Parent.getNumParams(); }
unsigned ScopStmt::getNumIterators() const { return NestLoops.size(); }
const char *ScopStmt::getBaseName() const { return BaseName.c_str(); }
const Loop *ScopStmt::getLoopForDimension(unsigned Dimension) const {
return NestLoops[Dimension];
}
isl_ctx *ScopStmt::getIslCtx() const { return Parent.getIslCtx(); }
__isl_give isl_set *ScopStmt::getDomain() const { return isl_set_copy(Domain); }
__isl_give isl_space *ScopStmt::getDomainSpace() const {
return isl_set_get_space(Domain);
}
__isl_give isl_id *ScopStmt::getDomainId() const {
return isl_set_get_tuple_id(Domain);
}
ScopStmt::~ScopStmt() { isl_set_free(Domain); }
void ScopStmt::print(raw_ostream &OS) const {
OS << "\t" << getBaseName() << "\n";
OS.indent(12) << "Domain :=\n";
if (Domain) {
OS.indent(16) << getDomainStr() << ";\n";
} else
OS.indent(16) << "n/a\n";
OS.indent(12) << "Schedule :=\n";
if (Domain) {
OS.indent(16) << getScheduleStr() << ";\n";
} else
OS.indent(16) << "n/a\n";
for (MemoryAccess *Access : MemAccs)
Access->print(OS);
}
void ScopStmt::dump() const { print(dbgs()); }
void ScopStmt::removeMemoryAccesses(MemoryAccessList &InvMAs) {
// Remove all memory accesses in @p InvMAs from this statement
// together with all scalar accesses that were caused by them.
for (MemoryAccess *MA : InvMAs) {
auto Predicate = [&](MemoryAccess *Acc) {
return Acc->getAccessInstruction() == MA->getAccessInstruction();
};
MemAccs.erase(std::remove_if(MemAccs.begin(), MemAccs.end(), Predicate),
MemAccs.end());
InstructionToAccess.erase(MA->getAccessInstruction());
}
}
//===----------------------------------------------------------------------===//
/// Scop class implement
void Scop::setContext(__isl_take isl_set *NewContext) {
NewContext = isl_set_align_params(NewContext, isl_set_get_space(Context));
isl_set_free(Context);
Context = NewContext;
}
/// @brief Remap parameter values but keep AddRecs valid wrt. invariant loads.
struct SCEVSensitiveParameterRewriter
: public SCEVVisitor<SCEVSensitiveParameterRewriter, const SCEV *> {
ValueToValueMap &VMap;
ScalarEvolution &SE;
public:
SCEVSensitiveParameterRewriter(ValueToValueMap &VMap, ScalarEvolution &SE)
: VMap(VMap), SE(SE) {}
static const SCEV *rewrite(const SCEV *E, ScalarEvolution &SE,
ValueToValueMap &VMap) {
SCEVSensitiveParameterRewriter SSPR(VMap, SE);
return SSPR.visit(E);
}
const SCEV *visit(const SCEV *E) {
return SCEVVisitor<SCEVSensitiveParameterRewriter, const SCEV *>::visit(E);
}
const SCEV *visitConstant(const SCEVConstant *E) { return E; }
const SCEV *visitTruncateExpr(const SCEVTruncateExpr *E) {
return SE.getTruncateExpr(visit(E->getOperand()), E->getType());
}
const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *E) {
return SE.getZeroExtendExpr(visit(E->getOperand()), E->getType());
}
const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *E) {
return SE.getSignExtendExpr(visit(E->getOperand()), E->getType());
}
const SCEV *visitAddExpr(const SCEVAddExpr *E) {
SmallVector<const SCEV *, 4> Operands;
for (int i = 0, e = E->getNumOperands(); i < e; ++i)
Operands.push_back(visit(E->getOperand(i)));
return SE.getAddExpr(Operands);
}
const SCEV *visitMulExpr(const SCEVMulExpr *E) {
SmallVector<const SCEV *, 4> Operands;
for (int i = 0, e = E->getNumOperands(); i < e; ++i)
Operands.push_back(visit(E->getOperand(i)));
return SE.getMulExpr(Operands);
}
const SCEV *visitSMaxExpr(const SCEVSMaxExpr *E) {
SmallVector<const SCEV *, 4> Operands;
for (int i = 0, e = E->getNumOperands(); i < e; ++i)
Operands.push_back(visit(E->getOperand(i)));
return SE.getSMaxExpr(Operands);
}
const SCEV *visitUMaxExpr(const SCEVUMaxExpr *E) {
SmallVector<const SCEV *, 4> Operands;
for (int i = 0, e = E->getNumOperands(); i < e; ++i)
Operands.push_back(visit(E->getOperand(i)));
return SE.getUMaxExpr(Operands);
}
const SCEV *visitUDivExpr(const SCEVUDivExpr *E) {
return SE.getUDivExpr(visit(E->getLHS()), visit(E->getRHS()));
}
const SCEV *visitAddRecExpr(const SCEVAddRecExpr *E) {
auto *Start = visit(E->getStart());
auto *AddRec = SE.getAddRecExpr(SE.getConstant(E->getType(), 0),
visit(E->getStepRecurrence(SE)),
E->getLoop(), SCEV::FlagAnyWrap);
return SE.getAddExpr(Start, AddRec);
}
const SCEV *visitUnknown(const SCEVUnknown *E) {
if (auto *NewValue = VMap.lookup(E->getValue()))
return SE.getUnknown(NewValue);
return E;
}
};
const SCEV *Scop::getRepresentingInvariantLoadSCEV(const SCEV *S) {
return SCEVSensitiveParameterRewriter::rewrite(S, *SE, InvEquivClassVMap);
}
void Scop::addParams(std::vector<const SCEV *> NewParameters) {
for (const SCEV *Parameter : NewParameters) {
Parameter = extractConstantFactor(Parameter, *SE).second;
// Normalize the SCEV to get the representing element for an invariant load.
Parameter = getRepresentingInvariantLoadSCEV(Parameter);
if (ParameterIds.find(Parameter) != ParameterIds.end())
continue;
int dimension = Parameters.size();
Parameters.push_back(Parameter);
ParameterIds[Parameter] = dimension;
}
}
__isl_give isl_id *Scop::getIdForParam(const SCEV *Parameter) {
// Normalize the SCEV to get the representing element for an invariant load.
Parameter = getRepresentingInvariantLoadSCEV(Parameter);
ParamIdType::const_iterator IdIter = ParameterIds.find(Parameter);
if (IdIter == ParameterIds.end())
return nullptr;
std::string ParameterName;
ParameterName = "p_" + utostr_32(IdIter->second);
if (const SCEVUnknown *ValueParameter = dyn_cast<SCEVUnknown>(Parameter)) {
Value *Val = ValueParameter->getValue();
// If this parameter references a specific Value and this value has a name
// we use this name as it is likely to be unique and more useful than just
// a number.
if (Val->hasName())
ParameterName = Val->getName();
else if (LoadInst *LI = dyn_cast<LoadInst>(Val)) {
auto LoadOrigin = LI->getPointerOperand()->stripInBoundsOffsets();
if (LoadOrigin->hasName()) {
ParameterName += "_loaded_from_";
ParameterName +=
LI->getPointerOperand()->stripInBoundsOffsets()->getName();
}
}
}
return isl_id_alloc(getIslCtx(), ParameterName.c_str(),
const_cast<void *>((const void *)Parameter));
}
isl_set *Scop::addNonEmptyDomainConstraints(isl_set *C) const {
isl_set *DomainContext = isl_union_set_params(getDomains());
return isl_set_intersect_params(C, DomainContext);
}
void Scop::buildBoundaryContext() {
if (IgnoreIntegerWrapping) {
BoundaryContext = isl_set_universe(getParamSpace());
return;
}
BoundaryContext = Affinator.getWrappingContext();
// The isl_set_complement operation used to create the boundary context
// can possibly become very expensive. We bound the compile time of
// this operation by setting a compute out.
//
// TODO: We can probably get around using isl_set_complement and directly
// AST generate BoundaryContext.
long MaxOpsOld = isl_ctx_get_max_operations(getIslCtx());
isl_ctx_reset_operations(getIslCtx());
isl_ctx_set_max_operations(getIslCtx(), 300000);
isl_options_set_on_error(getIslCtx(), ISL_ON_ERROR_CONTINUE);
BoundaryContext = isl_set_complement(BoundaryContext);
if (isl_ctx_last_error(getIslCtx()) == isl_error_quota) {
isl_set_free(BoundaryContext);
BoundaryContext = isl_set_empty(getParamSpace());
}
isl_options_set_on_error(getIslCtx(), ISL_ON_ERROR_ABORT);
isl_ctx_reset_operations(getIslCtx());
isl_ctx_set_max_operations(getIslCtx(), MaxOpsOld);
BoundaryContext = isl_set_gist_params(BoundaryContext, getContext());
trackAssumption(WRAPPING, BoundaryContext, DebugLoc());
}
void Scop::addUserAssumptions(AssumptionCache &AC) {
auto *R = &getRegion();
auto &F = *R->getEntry()->getParent();
for (auto &Assumption : AC.assumptions()) {
auto *CI = dyn_cast_or_null<CallInst>(Assumption);
if (!CI || CI->getNumArgOperands() != 1)
continue;
if (!DT.dominates(CI->getParent(), R->getEntry()))
continue;
auto *Val = CI->getArgOperand(0);
std::vector<const SCEV *> Params;
if (!isAffineParamConstraint(Val, R, *SE, Params)) {
emitOptimizationRemarkAnalysis(F.getContext(), DEBUG_TYPE, F,
CI->getDebugLoc(),
"Non-affine user assumption ignored.");
continue;
}
addParams(Params);
auto *L = LI.getLoopFor(CI->getParent());
SmallVector<isl_set *, 2> ConditionSets;
buildConditionSets(*this, Val, nullptr, L, Context, ConditionSets);
assert(ConditionSets.size() == 2);
isl_set_free(ConditionSets[1]);
auto *AssumptionCtx = ConditionSets[0];
emitOptimizationRemarkAnalysis(
F.getContext(), DEBUG_TYPE, F, CI->getDebugLoc(),
"Use user assumption: " + stringFromIslObj(AssumptionCtx));
Context = isl_set_intersect(Context, AssumptionCtx);
}
}
void Scop::addUserContext() {
if (UserContextStr.empty())
return;
isl_set *UserContext = isl_set_read_from_str(IslCtx, UserContextStr.c_str());
isl_space *Space = getParamSpace();
if (isl_space_dim(Space, isl_dim_param) !=
isl_set_dim(UserContext, isl_dim_param)) {
auto SpaceStr = isl_space_to_str(Space);
errs() << "Error: the context provided in -polly-context has not the same "
<< "number of dimensions than the computed context. Due to this "
<< "mismatch, the -polly-context option is ignored. Please provide "
<< "the context in the parameter space: " << SpaceStr << ".\n";
free(SpaceStr);
isl_set_free(UserContext);
isl_space_free(Space);
return;
}
for (unsigned i = 0; i < isl_space_dim(Space, isl_dim_param); i++) {
auto NameContext = isl_set_get_dim_name(Context, isl_dim_param, i);
auto NameUserContext = isl_set_get_dim_name(UserContext, isl_dim_param, i);
if (strcmp(NameContext, NameUserContext) != 0) {
auto SpaceStr = isl_space_to_str(Space);
errs() << "Error: the name of dimension " << i
<< " provided in -polly-context "
<< "is '" << NameUserContext << "', but the name in the computed "
<< "context is '" << NameContext
<< "'. Due to this name mismatch, "
<< "the -polly-context option is ignored. Please provide "
<< "the context in the parameter space: " << SpaceStr << ".\n";
free(SpaceStr);
isl_set_free(UserContext);
isl_space_free(Space);
return;
}
UserContext =
isl_set_set_dim_id(UserContext, isl_dim_param, i,
isl_space_get_dim_id(Space, isl_dim_param, i));
}
Context = isl_set_intersect(Context, UserContext);
isl_space_free(Space);
}
void Scop::buildInvariantEquivalenceClasses() {
DenseMap<const SCEV *, LoadInst *> EquivClasses;
const InvariantLoadsSetTy &RIL = *SD.getRequiredInvariantLoads(&getRegion());
for (LoadInst *LInst : RIL) {
const SCEV *PointerSCEV = SE->getSCEV(LInst->getPointerOperand());
LoadInst *&ClassRep = EquivClasses[PointerSCEV];
if (ClassRep) {
InvEquivClassVMap[LInst] = ClassRep;
continue;
}
ClassRep = LInst;
InvariantEquivClasses.emplace_back(PointerSCEV, MemoryAccessList(),
nullptr);
}
}
void Scop::buildContext() {
isl_space *Space = isl_space_params_alloc(IslCtx, 0);
Context = isl_set_universe(isl_space_copy(Space));
AssumedContext = isl_set_universe(Space);
}
void Scop::addParameterBounds() {
for (const auto &ParamID : ParameterIds) {
int dim = ParamID.second;
ConstantRange SRange = SE->getSignedRange(ParamID.first);
Context = addRangeBoundsToSet(Context, SRange, dim, isl_dim_param);
}
}
void Scop::realignParams() {
// Add all parameters into a common model.
isl_space *Space = isl_space_params_alloc(IslCtx, ParameterIds.size());
for (const auto &ParamID : ParameterIds) {
const SCEV *Parameter = ParamID.first;
isl_id *id = getIdForParam(Parameter);
Space = isl_space_set_dim_id(Space, isl_dim_param, ParamID.second, id);
}
// Align the parameters of all data structures to the model.
Context = isl_set_align_params(Context, Space);
for (ScopStmt &Stmt : *this)
Stmt.realignParams();
}
static __isl_give isl_set *
simplifyAssumptionContext(__isl_take isl_set *AssumptionContext,
const Scop &S) {
// If we modelt all blocks in the SCoP that have side effects we can simplify
// the context with the constraints that are needed for anything to be
// executed at all. However, if we have error blocks in the SCoP we already
// assumed some parameter combinations cannot occure and removed them from the
// domains, thus we cannot use the remaining domain to simplify the
// assumptions.
if (!S.hasErrorBlock()) {
isl_set *DomainParameters = isl_union_set_params(S.getDomains());
AssumptionContext =
isl_set_gist_params(AssumptionContext, DomainParameters);
}
AssumptionContext = isl_set_gist_params(AssumptionContext, S.getContext());
return AssumptionContext;
}
void Scop::simplifyContexts() {
// The parameter constraints of the iteration domains give us a set of
// constraints that need to hold for all cases where at least a single
// statement iteration is executed in the whole scop. We now simplify the
// assumed context under the assumption that such constraints hold and at
// least a single statement iteration is executed. For cases where no
// statement instances are executed, the assumptions we have taken about
// the executed code do not matter and can be changed.
//
// WARNING: This only holds if the assumptions we have taken do not reduce
// the set of statement instances that are executed. Otherwise we
// may run into a case where the iteration domains suggest that
// for a certain set of parameter constraints no code is executed,
// but in the original program some computation would have been
// performed. In such a case, modifying the run-time conditions and
// possibly influencing the run-time check may cause certain scops
// to not be executed.
//
// Example:
//
// When delinearizing the following code:
//
// for (long i = 0; i < 100; i++)
// for (long j = 0; j < m; j++)
// A[i+p][j] = 1.0;
//
// we assume that the condition m <= 0 or (m >= 1 and p >= 0) holds as
// otherwise we would access out of bound data. Now, knowing that code is
// only executed for the case m >= 0, it is sufficient to assume p >= 0.
AssumedContext = simplifyAssumptionContext(AssumedContext, *this);
BoundaryContext = simplifyAssumptionContext(BoundaryContext, *this);
}
/// @brief Add the minimal/maximal access in @p Set to @p User.
static isl_stat buildMinMaxAccess(__isl_take isl_set *Set, void *User) {
Scop::MinMaxVectorTy *MinMaxAccesses = (Scop::MinMaxVectorTy *)User;
isl_pw_multi_aff *MinPMA, *MaxPMA;
isl_pw_aff *LastDimAff;
isl_aff *OneAff;
unsigned Pos;
// Restrict the number of parameters involved in the access as the lexmin/
// lexmax computation will take too long if this number is high.
//
// Experiments with a simple test case using an i7 4800MQ:
//
// #Parameters involved | Time (in sec)
// 6 | 0.01
// 7 | 0.04
// 8 | 0.12
// 9 | 0.40
// 10 | 1.54
// 11 | 6.78
// 12 | 30.38
//
if (isl_set_n_param(Set) > RunTimeChecksMaxParameters) {
unsigned InvolvedParams = 0;
for (unsigned u = 0, e = isl_set_n_param(Set); u < e; u++)
if (isl_set_involves_dims(Set, isl_dim_param, u, 1))
InvolvedParams++;
if (InvolvedParams > RunTimeChecksMaxParameters) {
isl_set_free(Set);
return isl_stat_error;
}
}
Set = isl_set_remove_divs(Set);
MinPMA = isl_set_lexmin_pw_multi_aff(isl_set_copy(Set));
MaxPMA = isl_set_lexmax_pw_multi_aff(isl_set_copy(Set));
MinPMA = isl_pw_multi_aff_coalesce(MinPMA);
MaxPMA = isl_pw_multi_aff_coalesce(MaxPMA);
// Adjust the last dimension of the maximal access by one as we want to
// enclose the accessed memory region by MinPMA and MaxPMA. The pointer
// we test during code generation might now point after the end of the
// allocated array but we will never dereference it anyway.
assert(isl_pw_multi_aff_dim(MaxPMA, isl_dim_out) &&
"Assumed at least one output dimension");
Pos = isl_pw_multi_aff_dim(MaxPMA, isl_dim_out) - 1;
LastDimAff = isl_pw_multi_aff_get_pw_aff(MaxPMA, Pos);
OneAff = isl_aff_zero_on_domain(
isl_local_space_from_space(isl_pw_aff_get_domain_space(LastDimAff)));
OneAff = isl_aff_add_constant_si(OneAff, 1);
LastDimAff = isl_pw_aff_add(LastDimAff, isl_pw_aff_from_aff(OneAff));
MaxPMA = isl_pw_multi_aff_set_pw_aff(MaxPMA, Pos, LastDimAff);
MinMaxAccesses->push_back(std::make_pair(MinPMA, MaxPMA));
isl_set_free(Set);
return isl_stat_ok;
}
static __isl_give isl_set *getAccessDomain(MemoryAccess *MA) {
isl_set *Domain = MA->getStatement()->getDomain();
Domain = isl_set_project_out(Domain, isl_dim_set, 0, isl_set_n_dim(Domain));
return isl_set_reset_tuple_id(Domain);
}
/// @brief Wrapper function to calculate minimal/maximal accesses to each array.
static bool calculateMinMaxAccess(__isl_take isl_union_map *Accesses,
__isl_take isl_union_set *Domains,
Scop::MinMaxVectorTy &MinMaxAccesses) {
Accesses = isl_union_map_intersect_domain(Accesses, Domains);
isl_union_set *Locations = isl_union_map_range(Accesses);
Locations = isl_union_set_coalesce(Locations);
Locations = isl_union_set_detect_equalities(Locations);
bool Valid = (0 == isl_union_set_foreach_set(Locations, buildMinMaxAccess,
&MinMaxAccesses));
isl_union_set_free(Locations);
return Valid;
}
/// @brief Helper to treat non-affine regions and basic blocks the same.
///
///{
/// @brief Return the block that is the representing block for @p RN.
static inline BasicBlock *getRegionNodeBasicBlock(RegionNode *RN) {
return RN->isSubRegion() ? RN->getNodeAs<Region>()->getEntry()
: RN->getNodeAs<BasicBlock>();
}
/// @brief Return the @p idx'th block that is executed after @p RN.
static inline BasicBlock *
getRegionNodeSuccessor(RegionNode *RN, TerminatorInst *TI, unsigned idx) {
if (RN->isSubRegion()) {
assert(idx == 0);
return RN->getNodeAs<Region>()->getExit();
}
return TI->getSuccessor(idx);
}
/// @brief Return the smallest loop surrounding @p RN.
static inline Loop *getRegionNodeLoop(RegionNode *RN, LoopInfo &LI) {
if (!RN->isSubRegion())
return LI.getLoopFor(RN->getNodeAs<BasicBlock>());
Region *NonAffineSubRegion = RN->getNodeAs<Region>();
Loop *L = LI.getLoopFor(NonAffineSubRegion->getEntry());
while (L && NonAffineSubRegion->contains(L))
L = L->getParentLoop();
return L;
}
static inline unsigned getNumBlocksInRegionNode(RegionNode *RN) {
if (!RN->isSubRegion())
return 1;
Region *R = RN->getNodeAs<Region>();
return std::distance(R->block_begin(), R->block_end());
}
static bool containsErrorBlock(RegionNode *RN, const Region &R, LoopInfo &LI,
const DominatorTree &DT) {
if (!RN->isSubRegion())
return isErrorBlock(*RN->getNodeAs<BasicBlock>(), R, LI, DT);
for (BasicBlock *BB : RN->getNodeAs<Region>()->blocks())
if (isErrorBlock(*BB, R, LI, DT))
return true;
return false;
}
///}
static inline __isl_give isl_set *addDomainDimId(__isl_take isl_set *Domain,
unsigned Dim, Loop *L) {
Domain = isl_set_lower_bound_si(Domain, isl_dim_set, Dim, -1);
isl_id *DimId =
isl_id_alloc(isl_set_get_ctx(Domain), nullptr, static_cast<void *>(L));
return isl_set_set_dim_id(Domain, isl_dim_set, Dim, DimId);
}
isl_set *Scop::getDomainConditions(ScopStmt *Stmt) {
BasicBlock *BB = Stmt->isBlockStmt() ? Stmt->getBasicBlock()
: Stmt->getRegion()->getEntry();
return getDomainConditions(BB);
}
isl_set *Scop::getDomainConditions(BasicBlock *BB) {
assert(DomainMap.count(BB) && "Requested BB did not have a domain");
return isl_set_copy(DomainMap[BB]);
}
void Scop::removeErrorBlockDomains() {
auto removeDomains = [this](BasicBlock *Start) {
auto BBNode = DT.getNode(Start);
for (auto ErrorChild : depth_first(BBNode)) {
auto ErrorChildBlock = ErrorChild->getBlock();
auto CurrentDomain = DomainMap[ErrorChildBlock];
auto Empty = isl_set_empty(isl_set_get_space(CurrentDomain));
DomainMap[ErrorChildBlock] = Empty;
isl_set_free(CurrentDomain);
}
};
SmallVector<Region *, 4> Todo = {&R};
while (!Todo.empty()) {
auto SubRegion = Todo.back();
Todo.pop_back();
if (!SD.isNonAffineSubRegion(SubRegion, &getRegion())) {
for (auto &Child : *SubRegion)
Todo.push_back(Child.get());
continue;
}
if (containsErrorBlock(SubRegion->getNode(), getRegion(), LI, DT))
removeDomains(SubRegion->getEntry());
}
for (auto BB : R.blocks())
if (isErrorBlock(*BB, R, LI, DT))
removeDomains(BB);
}
void Scop::buildDomains(Region *R) {
bool IsOnlyNonAffineRegion = SD.isNonAffineSubRegion(R, R);
auto *EntryBB = R->getEntry();
auto *L = IsOnlyNonAffineRegion ? nullptr : LI.getLoopFor(EntryBB);
int LD = getRelativeLoopDepth(L);
auto *S = isl_set_universe(isl_space_set_alloc(getIslCtx(), 0, LD + 1));
while (LD-- >= 0) {
S = addDomainDimId(S, LD + 1, L);
L = L->getParentLoop();
}
DomainMap[EntryBB] = S;
if (IsOnlyNonAffineRegion)
return;
buildDomainsWithBranchConstraints(R);
propagateDomainConstraints(R);
// Error blocks and blocks dominated by them have been assumed to never be
// executed. Representing them in the Scop does not add any value. In fact,
// it is likely to cause issues during construction of the ScopStmts. The
// contents of error blocks have not been verfied to be expressible and
// will cause problems when building up a ScopStmt for them.
// Furthermore, basic blocks dominated by error blocks may reference
// instructions in the error block which, if the error block is not modeled,
// can themselves not be constructed properly.
removeErrorBlockDomains();
}
void Scop::buildDomainsWithBranchConstraints(Region *R) {
auto &BoxedLoops = *SD.getBoxedLoops(&getRegion());
// To create the domain for each block in R we iterate over all blocks and
// subregions in R and propagate the conditions under which the current region
// element is executed. To this end we iterate in reverse post order over R as
// it ensures that we first visit all predecessors of a region node (either a
// basic block or a subregion) before we visit the region node itself.
// Initially, only the domain for the SCoP region entry block is set and from
// there we propagate the current domain to all successors, however we add the
// condition that the successor is actually executed next.
// As we are only interested in non-loop carried constraints here we can
// simply skip loop back edges.
ReversePostOrderTraversal<Region *> RTraversal(R);
for (auto *RN : RTraversal) {
// Recurse for affine subregions but go on for basic blocks and non-affine
// subregions.
if (RN->isSubRegion()) {
Region *SubRegion = RN->getNodeAs<Region>();
if (!SD.isNonAffineSubRegion(SubRegion, &getRegion())) {
buildDomainsWithBranchConstraints(SubRegion);
continue;
}
}
if (containsErrorBlock(RN, getRegion(), LI, DT))
HasErrorBlock = true;
BasicBlock *BB = getRegionNodeBasicBlock(RN);
TerminatorInst *TI = BB->getTerminator();
if (isa<UnreachableInst>(TI))
continue;
isl_set *Domain = DomainMap.lookup(BB);
if (!Domain) {
DEBUG(dbgs() << "\tSkip: " << BB->getName()
<< ", it is only reachable from error blocks.\n");
continue;
}
DEBUG(dbgs() << "\tVisit: " << BB->getName() << " : " << Domain << "\n");
Loop *BBLoop = getRegionNodeLoop(RN, LI);
int BBLoopDepth = getRelativeLoopDepth(BBLoop);
// Build the condition sets for the successor nodes of the current region
// node. If it is a non-affine subregion we will always execute the single
// exit node, hence the single entry node domain is the condition set. For
// basic blocks we use the helper function buildConditionSets.
SmallVector<isl_set *, 8> ConditionSets;
if (RN->isSubRegion())
ConditionSets.push_back(isl_set_copy(Domain));
else
buildConditionSets(*this, TI, BBLoop, Domain, ConditionSets);
// Now iterate over the successors and set their initial domain based on
// their condition set. We skip back edges here and have to be careful when
// we leave a loop not to keep constraints over a dimension that doesn't
// exist anymore.
assert(RN->isSubRegion() || TI->getNumSuccessors() == ConditionSets.size());
for (unsigned u = 0, e = ConditionSets.size(); u < e; u++) {
isl_set *CondSet = ConditionSets[u];
BasicBlock *SuccBB = getRegionNodeSuccessor(RN, TI, u);
// Skip back edges.
if (DT.dominates(SuccBB, BB)) {
isl_set_free(CondSet);
continue;
}
// Do not adjust the number of dimensions if we enter a boxed loop or are
// in a non-affine subregion or if the surrounding loop stays the same.
Loop *SuccBBLoop = LI.getLoopFor(SuccBB);
while (BoxedLoops.count(SuccBBLoop))
SuccBBLoop = SuccBBLoop->getParentLoop();
if (BBLoop != SuccBBLoop) {
// Check if the edge to SuccBB is a loop entry or exit edge. If so
// adjust the dimensionality accordingly. Lastly, if we leave a loop
// and enter a new one we need to drop the old constraints.
int SuccBBLoopDepth = getRelativeLoopDepth(SuccBBLoop);
unsigned LoopDepthDiff = std::abs(BBLoopDepth - SuccBBLoopDepth);
if (BBLoopDepth > SuccBBLoopDepth) {
CondSet = isl_set_project_out(CondSet, isl_dim_set,
isl_set_n_dim(CondSet) - LoopDepthDiff,
LoopDepthDiff);
} else if (SuccBBLoopDepth > BBLoopDepth) {
assert(LoopDepthDiff == 1);
CondSet = isl_set_add_dims(CondSet, isl_dim_set, 1);
CondSet = addDomainDimId(CondSet, SuccBBLoopDepth, SuccBBLoop);
} else if (BBLoopDepth >= 0) {
assert(LoopDepthDiff <= 1);
CondSet = isl_set_project_out(CondSet, isl_dim_set, BBLoopDepth, 1);
CondSet = isl_set_add_dims(CondSet, isl_dim_set, 1);
CondSet = addDomainDimId(CondSet, SuccBBLoopDepth, SuccBBLoop);
}
}
// Set the domain for the successor or merge it with an existing domain in
// case there are multiple paths (without loop back edges) to the
// successor block.
isl_set *&SuccDomain = DomainMap[SuccBB];
if (!SuccDomain)
SuccDomain = CondSet;
else
SuccDomain = isl_set_union(SuccDomain, CondSet);
SuccDomain = isl_set_coalesce(SuccDomain);
if (isl_set_n_basic_set(SuccDomain) > MaxConjunctsInDomain) {
auto *Empty = isl_set_empty(isl_set_get_space(SuccDomain));
isl_set_free(SuccDomain);
SuccDomain = Empty;
invalidate(ERROR_DOMAINCONJUNCTS, DebugLoc());
}
DEBUG(dbgs() << "\tSet SuccBB: " << SuccBB->getName() << " : "
<< SuccDomain << "\n");
}
}
}
/// @brief Return the domain for @p BB wrt @p DomainMap.
///
/// This helper function will lookup @p BB in @p DomainMap but also handle the
/// case where @p BB is contained in a non-affine subregion using the region
/// tree obtained by @p RI.
static __isl_give isl_set *
getDomainForBlock(BasicBlock *BB, DenseMap<BasicBlock *, isl_set *> &DomainMap,
RegionInfo &RI) {
auto DIt = DomainMap.find(BB);
if (DIt != DomainMap.end())
return isl_set_copy(DIt->getSecond());
Region *R = RI.getRegionFor(BB);
while (R->getEntry() == BB)
R = R->getParent();
return getDomainForBlock(R->getEntry(), DomainMap, RI);
}
void Scop::propagateDomainConstraints(Region *R) {
// Iterate over the region R and propagate the domain constrains from the
// predecessors to the current node. In contrast to the
// buildDomainsWithBranchConstraints function, this one will pull the domain
// information from the predecessors instead of pushing it to the successors.
// Additionally, we assume the domains to be already present in the domain
// map here. However, we iterate again in reverse post order so we know all
// predecessors have been visited before a block or non-affine subregion is
// visited.
// The set of boxed loops (loops in non-affine subregions) for this SCoP.
auto &BoxedLoops = *SD.getBoxedLoops(&getRegion());
ReversePostOrderTraversal<Region *> RTraversal(R);
for (auto *RN : RTraversal) {
// Recurse for affine subregions but go on for basic blocks and non-affine
// subregions.
if (RN->isSubRegion()) {
Region *SubRegion = RN->getNodeAs<Region>();
if (!SD.isNonAffineSubRegion(SubRegion, &getRegion())) {
propagateDomainConstraints(SubRegion);
continue;
}
}
// Get the domain for the current block and check if it was initialized or
// not. The only way it was not is if this block is only reachable via error
// blocks, thus will not be executed under the assumptions we make. Such
// blocks have to be skipped as their predecessors might not have domains
// either. It would not benefit us to compute the domain anyway, only the
// domains of the error blocks that are reachable from non-error blocks
// are needed to generate assumptions.
BasicBlock *BB = getRegionNodeBasicBlock(RN);
isl_set *&Domain = DomainMap[BB];
if (!Domain) {
DEBUG(dbgs() << "\tSkip: " << BB->getName()
<< ", it is only reachable from error blocks.\n");
DomainMap.erase(BB);
continue;
}
DEBUG(dbgs() << "\tVisit: " << BB->getName() << " : " << Domain << "\n");
Loop *BBLoop = getRegionNodeLoop(RN, LI);
int BBLoopDepth = getRelativeLoopDepth(BBLoop);
isl_set *PredDom = isl_set_empty(isl_set_get_space(Domain));
for (auto *PredBB : predecessors(BB)) {
// Skip backedges
if (DT.dominates(BB, PredBB))
continue;
isl_set *PredBBDom = nullptr;
// Handle the SCoP entry block with its outside predecessors.
if (!getRegion().contains(PredBB))
PredBBDom = isl_set_universe(isl_set_get_space(PredDom));
if (!PredBBDom) {
// Determine the loop depth of the predecessor and adjust its domain to
// the domain of the current block. This can mean we have to:
// o) Drop a dimension if this block is the exit of a loop, not the
// header of a new loop and the predecessor was part of the loop.
// o) Add an unconstrainted new dimension if this block is the header
// of a loop and the predecessor is not part of it.
// o) Drop the information about the innermost loop dimension when the
// predecessor and the current block are surrounded by different
// loops in the same depth.
PredBBDom = getDomainForBlock(PredBB, DomainMap, *R->getRegionInfo());
Loop *PredBBLoop = LI.getLoopFor(PredBB);
while (BoxedLoops.count(PredBBLoop))
PredBBLoop = PredBBLoop->getParentLoop();
int PredBBLoopDepth = getRelativeLoopDepth(PredBBLoop);
unsigned LoopDepthDiff = std::abs(BBLoopDepth - PredBBLoopDepth);
if (BBLoopDepth < PredBBLoopDepth)
PredBBDom = isl_set_project_out(
PredBBDom, isl_dim_set, isl_set_n_dim(PredBBDom) - LoopDepthDiff,
LoopDepthDiff);
else if (PredBBLoopDepth < BBLoopDepth) {
assert(LoopDepthDiff == 1);
PredBBDom = isl_set_add_dims(PredBBDom, isl_dim_set, 1);
} else if (BBLoop != PredBBLoop && BBLoopDepth >= 0) {
assert(LoopDepthDiff <= 1);
PredBBDom = isl_set_drop_constraints_involving_dims(
PredBBDom, isl_dim_set, BBLoopDepth, 1);
}
}
PredDom = isl_set_union(PredDom, PredBBDom);
}
// Under the union of all predecessor conditions we can reach this block.
Domain = isl_set_coalesce(isl_set_intersect(Domain, PredDom));
if (BBLoop && BBLoop->getHeader() == BB && getRegion().contains(BBLoop))
addLoopBoundsToHeaderDomain(BBLoop);
// Add assumptions for error blocks.
if (containsErrorBlock(RN, getRegion(), LI, DT)) {
IsOptimized = true;
isl_set *DomPar = isl_set_params(isl_set_copy(Domain));
addAssumption(ERRORBLOCK, isl_set_complement(DomPar),
BB->getTerminator()->getDebugLoc());
}
}
}
/// @brief Create a map from SetSpace -> SetSpace where the dimensions @p Dim
/// is incremented by one and all other dimensions are equal, e.g.,
/// [i0, i1, i2, i3] -> [i0, i1, i2 + 1, i3]
/// if @p Dim is 2 and @p SetSpace has 4 dimensions.
static __isl_give isl_map *
createNextIterationMap(__isl_take isl_space *SetSpace, unsigned Dim) {
auto *MapSpace = isl_space_map_from_set(SetSpace);
auto *NextIterationMap = isl_map_universe(isl_space_copy(MapSpace));
for (unsigned u = 0; u < isl_map_n_in(NextIterationMap); u++)
if (u != Dim)
NextIterationMap =
isl_map_equate(NextIterationMap, isl_dim_in, u, isl_dim_out, u);
auto *C = isl_constraint_alloc_equality(isl_local_space_from_space(MapSpace));
C = isl_constraint_set_constant_si(C, 1);
C = isl_constraint_set_coefficient_si(C, isl_dim_in, Dim, 1);
C = isl_constraint_set_coefficient_si(C, isl_dim_out, Dim, -1);
NextIterationMap = isl_map_add_constraint(NextIterationMap, C);
return NextIterationMap;
}
void Scop::addLoopBoundsToHeaderDomain(Loop *L) {
int LoopDepth = getRelativeLoopDepth(L);
assert(LoopDepth >= 0 && "Loop in region should have at least depth one");
BasicBlock *HeaderBB = L->getHeader();
assert(DomainMap.count(HeaderBB));
isl_set *&HeaderBBDom = DomainMap[HeaderBB];
isl_map *NextIterationMap =
createNextIterationMap(isl_set_get_space(HeaderBBDom), LoopDepth);
isl_set *UnionBackedgeCondition =
isl_set_empty(isl_set_get_space(HeaderBBDom));
SmallVector<llvm::BasicBlock *, 4> LatchBlocks;
L->getLoopLatches(LatchBlocks);
for (BasicBlock *LatchBB : LatchBlocks) {
// If the latch is only reachable via error statements we skip it.
isl_set *LatchBBDom = DomainMap.lookup(LatchBB);
if (!LatchBBDom)
continue;
isl_set *BackedgeCondition = nullptr;
TerminatorInst *TI = LatchBB->getTerminator();
BranchInst *BI = dyn_cast<BranchInst>(TI);
if (BI && BI->isUnconditional())
BackedgeCondition = isl_set_copy(LatchBBDom);
else {
SmallVector<isl_set *, 8> ConditionSets;
int idx = BI->getSuccessor(0) != HeaderBB;
buildConditionSets(*this, TI, L, LatchBBDom, ConditionSets);
// Free the non back edge condition set as we do not need it.
isl_set_free(ConditionSets[1 - idx]);
BackedgeCondition = ConditionSets[idx];
}
int LatchLoopDepth = getRelativeLoopDepth(LI.getLoopFor(LatchBB));
assert(LatchLoopDepth >= LoopDepth);
BackedgeCondition =
isl_set_project_out(BackedgeCondition, isl_dim_set, LoopDepth + 1,
LatchLoopDepth - LoopDepth);
UnionBackedgeCondition =
isl_set_union(UnionBackedgeCondition, BackedgeCondition);
}
isl_map *ForwardMap = isl_map_lex_le(isl_set_get_space(HeaderBBDom));
for (int i = 0; i < LoopDepth; i++)
ForwardMap = isl_map_equate(ForwardMap, isl_dim_in, i, isl_dim_out, i);
isl_set *UnionBackedgeConditionComplement =
isl_set_complement(UnionBackedgeCondition);
UnionBackedgeConditionComplement = isl_set_lower_bound_si(
UnionBackedgeConditionComplement, isl_dim_set, LoopDepth, 0);
UnionBackedgeConditionComplement =
isl_set_apply(UnionBackedgeConditionComplement, ForwardMap);
HeaderBBDom = isl_set_subtract(HeaderBBDom, UnionBackedgeConditionComplement);
HeaderBBDom = isl_set_apply(HeaderBBDom, NextIterationMap);
auto Parts = partitionSetParts(HeaderBBDom, LoopDepth);
HeaderBBDom = Parts.second;
// Check if there is a <nsw> tagged AddRec for this loop and if so do not add
// the bounded assumptions to the context as they are already implied by the
// <nsw> tag.
if (Affinator.hasNSWAddRecForLoop(L)) {
isl_set_free(Parts.first);
return;
}
isl_set *UnboundedCtx = isl_set_params(Parts.first);
isl_set *BoundedCtx = isl_set_complement(UnboundedCtx);
addAssumption(INFINITELOOP, BoundedCtx,
HeaderBB->getTerminator()->getDebugLoc());
}
void Scop::buildAliasChecks(AliasAnalysis &AA) {
if (!PollyUseRuntimeAliasChecks)
return;
if (buildAliasGroups(AA))
return;
// If a problem occurs while building the alias groups we need to delete
// this SCoP and pretend it wasn't valid in the first place. To this end
// we make the assumed context infeasible.
invalidate(ALIASING, DebugLoc());
DEBUG(dbgs() << "\n\nNOTE: Run time checks for " << getNameStr()
<< " could not be created as the number of parameters involved "
"is too high. The SCoP will be "
"dismissed.\nUse:\n\t--polly-rtc-max-parameters=X\nto adjust "
"the maximal number of parameters but be advised that the "
"compile time might increase exponentially.\n\n");
}
bool Scop::buildAliasGroups(AliasAnalysis &AA) {
// To create sound alias checks we perform the following steps:
// o) Use the alias analysis and an alias set tracker to build alias sets
// for all memory accesses inside the SCoP.
// o) For each alias set we then map the aliasing pointers back to the
// memory accesses we know, thus obtain groups of memory accesses which
// might alias.
// o) We divide each group based on the domains of the minimal/maximal
// accesses. That means two minimal/maximal accesses are only in a group
// if their access domains intersect, otherwise they are in different
// ones.
// o) We partition each group into read only and non read only accesses.
// o) For each group with more than one base pointer we then compute minimal
// and maximal accesses to each array of a group in read only and non
// read only partitions separately.
using AliasGroupTy = SmallVector<MemoryAccess *, 4>;
AliasSetTracker AST(AA);
DenseMap<Value *, MemoryAccess *> PtrToAcc;
DenseSet<Value *> HasWriteAccess;
for (ScopStmt &Stmt : *this) {
// Skip statements with an empty domain as they will never be executed.
isl_set *StmtDomain = Stmt.getDomain();
bool StmtDomainEmpty = isl_set_is_empty(StmtDomain);
isl_set_free(StmtDomain);
if (StmtDomainEmpty)
continue;
for (MemoryAccess *MA : Stmt) {
if (MA->isScalarKind())
continue;
if (!MA->isRead())
HasWriteAccess.insert(MA->getBaseAddr());
Instruction *Acc = MA->getAccessInstruction();
PtrToAcc[getPointerOperand(*Acc)] = MA;
AST.add(Acc);
}
}
SmallVector<AliasGroupTy, 4> AliasGroups;
for (AliasSet &AS : AST) {
if (AS.isMustAlias() || AS.isForwardingAliasSet())
continue;
AliasGroupTy AG;
for (auto PR : AS)
AG.push_back(PtrToAcc[PR.getValue()]);
assert(AG.size() > 1 &&
"Alias groups should contain at least two accesses");
AliasGroups.push_back(std::move(AG));
}
// Split the alias groups based on their domain.
for (unsigned u = 0; u < AliasGroups.size(); u++) {
AliasGroupTy NewAG;
AliasGroupTy &AG = AliasGroups[u];
AliasGroupTy::iterator AGI = AG.begin();
isl_set *AGDomain = getAccessDomain(*AGI);
while (AGI != AG.end()) {
MemoryAccess *MA = *AGI;
isl_set *MADomain = getAccessDomain(MA);
if (isl_set_is_disjoint(AGDomain, MADomain)) {
NewAG.push_back(MA);
AGI = AG.erase(AGI);
isl_set_free(MADomain);
} else {
AGDomain = isl_set_union(AGDomain, MADomain);
AGI++;
}
}
if (NewAG.size() > 1)
AliasGroups.push_back(std::move(NewAG));
isl_set_free(AGDomain);
}
auto &F = *getRegion().getEntry()->getParent();
MapVector<const Value *, SmallPtrSet<MemoryAccess *, 8>> ReadOnlyPairs;
SmallPtrSet<const Value *, 4> NonReadOnlyBaseValues;
for (AliasGroupTy &AG : AliasGroups) {
NonReadOnlyBaseValues.clear();
ReadOnlyPairs.clear();
if (AG.size() < 2) {
AG.clear();
continue;
}
for (auto II = AG.begin(); II != AG.end();) {
emitOptimizationRemarkAnalysis(
F.getContext(), DEBUG_TYPE, F,
(*II)->getAccessInstruction()->getDebugLoc(),
"Possibly aliasing pointer, use restrict keyword.");
Value *BaseAddr = (*II)->getBaseAddr();
if (HasWriteAccess.count(BaseAddr)) {
NonReadOnlyBaseValues.insert(BaseAddr);
II++;
} else {
ReadOnlyPairs[BaseAddr].insert(*II);
II = AG.erase(II);
}
}
// If we don't have read only pointers check if there are at least two
// non read only pointers, otherwise clear the alias group.
if (ReadOnlyPairs.empty() && NonReadOnlyBaseValues.size() <= 1) {
AG.clear();
continue;
}
// If we don't have non read only pointers clear the alias group.
if (NonReadOnlyBaseValues.empty()) {
AG.clear();
continue;
}
// Calculate minimal and maximal accesses for non read only accesses.
MinMaxAliasGroups.emplace_back();
MinMaxVectorPairTy &pair = MinMaxAliasGroups.back();
MinMaxVectorTy &MinMaxAccessesNonReadOnly = pair.first;
MinMaxVectorTy &MinMaxAccessesReadOnly = pair.second;
MinMaxAccessesNonReadOnly.reserve(AG.size());
isl_union_map *Accesses = isl_union_map_empty(getParamSpace());
// AG contains only non read only accesses.
for (MemoryAccess *MA : AG)
Accesses = isl_union_map_add_map(Accesses, MA->getAccessRelation());
bool Valid = calculateMinMaxAccess(Accesses, getDomains(),
MinMaxAccessesNonReadOnly);
// Bail out if the number of values we need to compare is too large.
// This is important as the number of comparisions grows quadratically with
// the number of values we need to compare.
if (!Valid || (MinMaxAccessesNonReadOnly.size() + !ReadOnlyPairs.empty() >
RunTimeChecksMaxArraysPerGroup))
return false;
// Calculate minimal and maximal accesses for read only accesses.
MinMaxAccessesReadOnly.reserve(ReadOnlyPairs.size());
Accesses = isl_union_map_empty(getParamSpace());
for (const auto &ReadOnlyPair : ReadOnlyPairs)
for (MemoryAccess *MA : ReadOnlyPair.second)
Accesses = isl_union_map_add_map(Accesses, MA->getAccessRelation());
Valid =
calculateMinMaxAccess(Accesses, getDomains(), MinMaxAccessesReadOnly);
if (!Valid)
return false;
}
return true;
}
/// @brief Get the smallest loop that contains @p R but is not in @p R.
static Loop *getLoopSurroundingRegion(Region &R, LoopInfo &LI) {
// Start with the smallest loop containing the entry and expand that
// loop until it contains all blocks in the region. If there is a loop
// containing all blocks in the region check if it is itself contained
// and if so take the parent loop as it will be the smallest containing
// the region but not contained by it.
Loop *L = LI.getLoopFor(R.getEntry());
while (L) {
bool AllContained = true;
for (auto *BB : R.blocks())
AllContained &= L->contains(BB);
if (AllContained)
break;
L = L->getParentLoop();
}
return L ? (R.contains(L) ? L->getParentLoop() : L) : nullptr;
}
static unsigned getMaxLoopDepthInRegion(const Region &R, LoopInfo &LI,
ScopDetection &SD) {
const ScopDetection::BoxedLoopsSetTy *BoxedLoops = SD.getBoxedLoops(&R);
unsigned MinLD = INT_MAX, MaxLD = 0;
for (BasicBlock *BB : R.blocks()) {
if (Loop *L = LI.getLoopFor(BB)) {
if (!R.contains(L))
continue;
if (BoxedLoops && BoxedLoops->count(L))
continue;
unsigned LD = L->getLoopDepth();
MinLD = std::min(MinLD, LD);
MaxLD = std::max(MaxLD, LD);
}
}
// Handle the case that there is no loop in the SCoP first.
if (MaxLD == 0)
return 1;
assert(MinLD >= 1 && "Minimal loop depth should be at least one");
assert(MaxLD >= MinLD &&
"Maximal loop depth was smaller than mininaml loop depth?");
return MaxLD - MinLD + 1;
}
Scop::Scop(Region &R, AccFuncMapType &AccFuncMap, ScopDetection &SD,
ScalarEvolution &ScalarEvolution, DominatorTree &DT, LoopInfo &LI,
isl_ctx *Context, unsigned MaxLoopDepth)
: LI(LI), DT(DT), SE(&ScalarEvolution), SD(SD), R(R),
AccFuncMap(AccFuncMap), IsOptimized(false),
HasSingleExitEdge(R.getExitingBlock()), HasErrorBlock(false),
MaxLoopDepth(MaxLoopDepth), IslCtx(Context), Context(nullptr),
Affinator(this), AssumedContext(nullptr), BoundaryContext(nullptr),
Schedule(nullptr) {}
void Scop::init(AliasAnalysis &AA, AssumptionCache &AC) {
buildContext();
addUserAssumptions(AC);
buildInvariantEquivalenceClasses();
buildDomains(&R);
// Remove empty and ignored statements.
// Exit early in case there are no executable statements left in this scop.
simplifySCoP(true);
if (Stmts.empty())
return;
// The ScopStmts now have enough information to initialize themselves.
for (ScopStmt &Stmt : Stmts)
Stmt.init();
buildSchedule();
if (isl_set_is_empty(AssumedContext))
return;
updateAccessDimensionality();
realignParams();
addParameterBounds();
addUserContext();
buildBoundaryContext();
simplifyContexts();
buildAliasChecks(AA);
hoistInvariantLoads();
simplifySCoP(false);
}
Scop::~Scop() {
isl_set_free(Context);
isl_set_free(AssumedContext);
isl_set_free(BoundaryContext);
isl_schedule_free(Schedule);
for (auto It : DomainMap)
isl_set_free(It.second);
// Free the alias groups
for (MinMaxVectorPairTy &MinMaxAccessPair : MinMaxAliasGroups) {
for (MinMaxAccessTy &MMA : MinMaxAccessPair.first) {
isl_pw_multi_aff_free(MMA.first);
isl_pw_multi_aff_free(MMA.second);
}
for (MinMaxAccessTy &MMA : MinMaxAccessPair.second) {
isl_pw_multi_aff_free(MMA.first);
isl_pw_multi_aff_free(MMA.second);
}
}
for (const auto &IAClass : InvariantEquivClasses)
isl_set_free(std::get<2>(IAClass));
}
void Scop::updateAccessDimensionality() {
for (auto &Stmt : *this)
for (auto &Access : Stmt)
Access->updateDimensionality();
}
void Scop::simplifySCoP(bool RemoveIgnoredStmts) {
for (auto StmtIt = Stmts.begin(), StmtEnd = Stmts.end(); StmtIt != StmtEnd;) {
ScopStmt &Stmt = *StmtIt;
RegionNode *RN = Stmt.isRegionStmt()
? Stmt.getRegion()->getNode()
: getRegion().getBBNode(Stmt.getBasicBlock());
bool RemoveStmt = StmtIt->isEmpty();
if (!RemoveStmt)
RemoveStmt = isl_set_is_empty(DomainMap[getRegionNodeBasicBlock(RN)]);
if (!RemoveStmt)
RemoveStmt = (RemoveIgnoredStmts && isIgnored(RN));
// Remove read only statements only after invariant loop hoisting.
if (!RemoveStmt && !RemoveIgnoredStmts) {
bool OnlyRead = true;
for (MemoryAccess *MA : Stmt) {
if (MA->isRead())
continue;
OnlyRead = false;
break;
}
RemoveStmt = OnlyRead;
}
if (RemoveStmt) {
// Remove the statement because it is unnecessary.
if (Stmt.isRegionStmt())
for (BasicBlock *BB : Stmt.getRegion()->blocks())
StmtMap.erase(BB);
else
StmtMap.erase(Stmt.getBasicBlock());
StmtIt = Stmts.erase(StmtIt);
continue;
}
StmtIt++;
}
}
const InvariantEquivClassTy *Scop::lookupInvariantEquivClass(Value *Val) const {
LoadInst *LInst = dyn_cast<LoadInst>(Val);
if (!LInst)
return nullptr;
if (Value *Rep = InvEquivClassVMap.lookup(LInst))
LInst = cast<LoadInst>(Rep);
const SCEV *PointerSCEV = SE->getSCEV(LInst->getPointerOperand());
for (auto &IAClass : InvariantEquivClasses)
if (PointerSCEV == std::get<0>(IAClass))
return &IAClass;
return nullptr;
}
void Scop::addInvariantLoads(ScopStmt &Stmt, MemoryAccessList &InvMAs) {
// Get the context under which the statement is executed.
isl_set *DomainCtx = isl_set_params(Stmt.getDomain());
DomainCtx = isl_set_remove_redundancies(DomainCtx);
DomainCtx = isl_set_detect_equalities(DomainCtx);
DomainCtx = isl_set_coalesce(DomainCtx);
// Project out all parameters that relate to loads in the statement. Otherwise
// we could have cyclic dependences on the constraints under which the
// hoisted loads are executed and we could not determine an order in which to
// pre-load them. This happens because not only lower bounds are part of the
// domain but also upper bounds.
for (MemoryAccess *MA : InvMAs) {
Instruction *AccInst = MA->getAccessInstruction();
if (SE->isSCEVable(AccInst->getType())) {
SetVector<Value *> Values;
for (const SCEV *Parameter : Parameters) {
Values.clear();
findValues(Parameter, Values);
if (!Values.count(AccInst))
continue;
if (isl_id *ParamId = getIdForParam(Parameter)) {
int Dim = isl_set_find_dim_by_id(DomainCtx, isl_dim_param, ParamId);
DomainCtx = isl_set_eliminate(DomainCtx, isl_dim_param, Dim, 1);
isl_id_free(ParamId);
}
}
}
}
for (MemoryAccess *MA : InvMAs) {
// Check for another invariant access that accesses the same location as
// MA and if found consolidate them. Otherwise create a new equivalence
// class at the end of InvariantEquivClasses.
LoadInst *LInst = cast<LoadInst>(MA->getAccessInstruction());
const SCEV *PointerSCEV = SE->getSCEV(LInst->getPointerOperand());
bool Consolidated = false;
for (auto &IAClass : InvariantEquivClasses) {
if (PointerSCEV != std::get<0>(IAClass))
continue;
// If the pointer and the type is equal check if the access function wrt.
// to the domain is equal too. It can happen that the domain fixes
// parameter values and these can be different for distinct part of the
// SCoP. If this happens we cannot consolitate the loads but need to
// create a new invariant load equivalence class.
auto &MAs = std::get<1>(IAClass);
if (!MAs.empty()) {
auto *LastMA = MAs.front();
auto *AR = isl_map_range(MA->getAccessRelation());
auto *LastAR = isl_map_range(LastMA->getAccessRelation());
bool SameAR = isl_set_is_equal(AR, LastAR);
isl_set_free(AR);
isl_set_free(LastAR);
if (!SameAR)
continue;
}
// Add MA to the list of accesses that are in this class.
MAs.push_front(MA);
Consolidated = true;
// Unify the execution context of the class and this statement.
isl_set *&IAClassDomainCtx = std::get<2>(IAClass);
if (IAClassDomainCtx)
IAClassDomainCtx = isl_set_coalesce(
isl_set_union(IAClassDomainCtx, isl_set_copy(DomainCtx)));
else
IAClassDomainCtx = isl_set_copy(DomainCtx);
break;
}
if (Consolidated)
continue;
// If we did not consolidate MA, thus did not find an equivalence class
// for it, we create a new one.
InvariantEquivClasses.emplace_back(PointerSCEV, MemoryAccessList{MA},
isl_set_copy(DomainCtx));
}
isl_set_free(DomainCtx);
}
bool Scop::isHoistableAccess(MemoryAccess *Access,
__isl_keep isl_union_map *Writes) {
// TODO: Loads that are not loop carried, hence are in a statement with
// zero iterators, are by construction invariant, though we
// currently "hoist" them anyway. This is necessary because we allow
// them to be treated as parameters (e.g., in conditions) and our code
// generation would otherwise use the old value.
auto &Stmt = *Access->getStatement();
BasicBlock *BB =
Stmt.isBlockStmt() ? Stmt.getBasicBlock() : Stmt.getRegion()->getEntry();
if (Access->isScalarKind() || Access->isWrite() || !Access->isAffine())
return false;
// Skip accesses that have an invariant base pointer which is defined but
// not loaded inside the SCoP. This can happened e.g., if a readnone call
// returns a pointer that is used as a base address. However, as we want
// to hoist indirect pointers, we allow the base pointer to be defined in
// the region if it is also a memory access. Each ScopArrayInfo object
// that has a base pointer origin has a base pointer that is loaded and
// that it is invariant, thus it will be hoisted too. However, if there is
// no base pointer origin we check that the base pointer is defined
// outside the region.
const ScopArrayInfo *SAI = Access->getScopArrayInfo();
while (auto *BasePtrOriginSAI = SAI->getBasePtrOriginSAI())
SAI = BasePtrOriginSAI;
if (auto *BasePtrInst = dyn_cast<Instruction>(SAI->getBasePtr()))
if (R.contains(BasePtrInst))
return false;
// Skip accesses in non-affine subregions as they might not be executed
// under the same condition as the entry of the non-affine subregion.
if (BB != Access->getAccessInstruction()->getParent())
return false;
isl_map *AccessRelation = Access->getAccessRelation();
// Skip accesses that have an empty access relation. These can be caused
// by multiple offsets with a type cast in-between that cause the overall
// byte offset to be not divisible by the new types sizes.
if (isl_map_is_empty(AccessRelation)) {
isl_map_free(AccessRelation);
return false;
}
if (isl_map_involves_dims(AccessRelation, isl_dim_in, 0,
Stmt.getNumIterators())) {
isl_map_free(AccessRelation);
return false;
}
AccessRelation = isl_map_intersect_domain(AccessRelation, Stmt.getDomain());
isl_set *AccessRange = isl_map_range(AccessRelation);
isl_union_map *Written = isl_union_map_intersect_range(
isl_union_map_copy(Writes), isl_union_set_from_set(AccessRange));
bool IsWritten = !isl_union_map_is_empty(Written);
isl_union_map_free(Written);
if (IsWritten)
return false;
return true;
}
void Scop::verifyInvariantLoads() {
auto &RIL = *SD.getRequiredInvariantLoads(&getRegion());
for (LoadInst *LI : RIL) {
assert(LI && getRegion().contains(LI));
ScopStmt *Stmt = getStmtForBasicBlock(LI->getParent());
if (Stmt && Stmt->getArrayAccessOrNULLFor(LI)) {
invalidate(INVARIANTLOAD, LI->getDebugLoc());
return;
}
}
}
void Scop::hoistInvariantLoads() {
isl_union_map *Writes = getWrites();
for (ScopStmt &Stmt : *this) {
MemoryAccessList InvariantAccesses;
for (MemoryAccess *Access : Stmt)
if (isHoistableAccess(Access, Writes))
InvariantAccesses.push_front(Access);
// We inserted invariant accesses always in the front but need them to be
// sorted in a "natural order". The statements are already sorted in reverse
// post order and that suffices for the accesses too. The reason we require
// an order in the first place is the dependences between invariant loads
// that can be caused by indirect loads.
InvariantAccesses.reverse();
// Transfer the memory access from the statement to the SCoP.
Stmt.removeMemoryAccesses(InvariantAccesses);
addInvariantLoads(Stmt, InvariantAccesses);
}
isl_union_map_free(Writes);
verifyInvariantLoads();
}
const ScopArrayInfo *
Scop::getOrCreateScopArrayInfo(Value *BasePtr, Type *AccessType,
ArrayRef<const SCEV *> Sizes,
ScopArrayInfo::MemoryKind Kind) {
auto &SAI = ScopArrayInfoMap[std::make_pair(BasePtr, Kind)];
if (!SAI) {
auto &DL = getRegion().getEntry()->getModule()->getDataLayout();
SAI.reset(new ScopArrayInfo(BasePtr, AccessType, getIslCtx(), Sizes, Kind,
DL, this));
} else {
// In case of mismatching array sizes, we bail out by setting the run-time
// context to false.
if (!SAI->updateSizes(Sizes))
invalidate(DELINEARIZATION, DebugLoc());
}
return SAI.get();
}
const ScopArrayInfo *Scop::getScopArrayInfo(Value *BasePtr,
ScopArrayInfo::MemoryKind Kind) {
auto *SAI = ScopArrayInfoMap[std::make_pair(BasePtr, Kind)].get();
assert(SAI && "No ScopArrayInfo available for this base pointer");
return SAI;
}
std::string Scop::getContextStr() const { return stringFromIslObj(Context); }
std::string Scop::getAssumedContextStr() const {
return stringFromIslObj(AssumedContext);
}
std::string Scop::getBoundaryContextStr() const {
return stringFromIslObj(BoundaryContext);
}
std::string Scop::getNameStr() const {
std::string ExitName, EntryName;
raw_string_ostream ExitStr(ExitName);
raw_string_ostream EntryStr(EntryName);
R.getEntry()->printAsOperand(EntryStr, false);
EntryStr.str();
if (R.getExit()) {
R.getExit()->printAsOperand(ExitStr, false);
ExitStr.str();
} else
ExitName = "FunctionExit";
return EntryName + "---" + ExitName;
}
__isl_give isl_set *Scop::getContext() const { return isl_set_copy(Context); }
__isl_give isl_space *Scop::getParamSpace() const {
return isl_set_get_space(Context);
}
__isl_give isl_set *Scop::getAssumedContext() const {
return isl_set_copy(AssumedContext);
}
__isl_give isl_set *Scop::getRuntimeCheckContext() const {
isl_set *RuntimeCheckContext = getAssumedContext();
RuntimeCheckContext =
isl_set_intersect(RuntimeCheckContext, getBoundaryContext());
RuntimeCheckContext = simplifyAssumptionContext(RuntimeCheckContext, *this);
return RuntimeCheckContext;
}
bool Scop::hasFeasibleRuntimeContext() const {
isl_set *RuntimeCheckContext = getRuntimeCheckContext();
RuntimeCheckContext = addNonEmptyDomainConstraints(RuntimeCheckContext);
bool IsFeasible = !isl_set_is_empty(RuntimeCheckContext);
isl_set_free(RuntimeCheckContext);
return IsFeasible;
}
static std::string toString(AssumptionKind Kind) {
switch (Kind) {
case ALIASING:
return "No-aliasing";
case INBOUNDS:
return "Inbounds";
case WRAPPING:
return "No-overflows";
case ALIGNMENT:
return "Alignment";
case ERRORBLOCK:
return "No-error";
case INFINITELOOP:
return "Finite loop";
case INVARIANTLOAD:
return "Invariant load";
case DELINEARIZATION:
return "Delinearization";
case ERROR_DOMAINCONJUNCTS:
return "Low number of domain conjuncts";
}
llvm_unreachable("Unknown AssumptionKind!");
}
void Scop::trackAssumption(AssumptionKind Kind, __isl_keep isl_set *Set,
DebugLoc Loc) {
if (isl_set_is_subset(Context, Set))
return;
if (isl_set_is_subset(AssumedContext, Set))
return;
auto &F = *getRegion().getEntry()->getParent();
std::string Msg = toString(Kind) + " assumption:\t" + stringFromIslObj(Set);
emitOptimizationRemarkAnalysis(F.getContext(), DEBUG_TYPE, F, Loc, Msg);
}
void Scop::addAssumption(AssumptionKind Kind, __isl_take isl_set *Set,
DebugLoc Loc) {
trackAssumption(Kind, Set, Loc);
AssumedContext = isl_set_intersect(AssumedContext, Set);
int NSets = isl_set_n_basic_set(AssumedContext);
if (NSets >= MaxDisjunctsAssumed) {
isl_space *Space = isl_set_get_space(AssumedContext);
isl_set_free(AssumedContext);
AssumedContext = isl_set_empty(Space);
}
AssumedContext = isl_set_coalesce(AssumedContext);
}
void Scop::invalidate(AssumptionKind Kind, DebugLoc Loc) {
addAssumption(Kind, isl_set_empty(getParamSpace()), Loc);
}
__isl_give isl_set *Scop::getBoundaryContext() const {
return isl_set_copy(BoundaryContext);
}
void Scop::printContext(raw_ostream &OS) const {
OS << "Context:\n";
if (!Context) {
OS.indent(4) << "n/a\n\n";
return;
}
OS.indent(4) << getContextStr() << "\n";
OS.indent(4) << "Assumed Context:\n";
if (!AssumedContext) {
OS.indent(4) << "n/a\n\n";
return;
}
OS.indent(4) << getAssumedContextStr() << "\n";
OS.indent(4) << "Boundary Context:\n";
if (!BoundaryContext) {
OS.indent(4) << "n/a\n\n";
return;
}
OS.indent(4) << getBoundaryContextStr() << "\n";
for (const SCEV *Parameter : Parameters) {
int Dim = ParameterIds.find(Parameter)->second;
OS.indent(4) << "p" << Dim << ": " << *Parameter << "\n";
}
}
void Scop::printAliasAssumptions(raw_ostream &OS) const {
int noOfGroups = 0;
for (const MinMaxVectorPairTy &Pair : MinMaxAliasGroups) {
if (Pair.second.size() == 0)
noOfGroups += 1;
else
noOfGroups += Pair.second.size();
}
OS.indent(4) << "Alias Groups (" << noOfGroups << "):\n";
if (MinMaxAliasGroups.empty()) {
OS.indent(8) << "n/a\n";
return;
}
for (const MinMaxVectorPairTy &Pair : MinMaxAliasGroups) {
// If the group has no read only accesses print the write accesses.
if (Pair.second.empty()) {
OS.indent(8) << "[[";
for (const MinMaxAccessTy &MMANonReadOnly : Pair.first) {
OS << " <" << MMANonReadOnly.first << ", " << MMANonReadOnly.second
<< ">";
}
OS << " ]]\n";
}
for (const MinMaxAccessTy &MMAReadOnly : Pair.second) {
OS.indent(8) << "[[";
OS << " <" << MMAReadOnly.first << ", " << MMAReadOnly.second << ">";
for (const MinMaxAccessTy &MMANonReadOnly : Pair.first) {
OS << " <" << MMANonReadOnly.first << ", " << MMANonReadOnly.second
<< ">";
}
OS << " ]]\n";
}
}
}
void Scop::printStatements(raw_ostream &OS) const {
OS << "Statements {\n";
for (const ScopStmt &Stmt : *this)
OS.indent(4) << Stmt;
OS.indent(4) << "}\n";
}
void Scop::printArrayInfo(raw_ostream &OS) const {
OS << "Arrays {\n";
for (auto &Array : arrays())
Array.second->print(OS);
OS.indent(4) << "}\n";
OS.indent(4) << "Arrays (Bounds as pw_affs) {\n";
for (auto &Array : arrays())
Array.second->print(OS, /* SizeAsPwAff */ true);
OS.indent(4) << "}\n";
}
void Scop::print(raw_ostream &OS) const {
OS.indent(4) << "Function: " << getRegion().getEntry()->getParent()->getName()
<< "\n";
OS.indent(4) << "Region: " << getNameStr() << "\n";
OS.indent(4) << "Max Loop Depth: " << getMaxLoopDepth() << "\n";
OS.indent(4) << "Invariant Accesses: {\n";
for (const auto &IAClass : InvariantEquivClasses) {
const auto &MAs = std::get<1>(IAClass);
if (MAs.empty()) {
OS.indent(12) << "Class Pointer: " << *std::get<0>(IAClass) << "\n";
} else {
MAs.front()->print(OS);
OS.indent(12) << "Execution Context: " << std::get<2>(IAClass) << "\n";
}
}
OS.indent(4) << "}\n";
printContext(OS.indent(4));
printArrayInfo(OS.indent(4));
printAliasAssumptions(OS);
printStatements(OS.indent(4));
}
void Scop::dump() const { print(dbgs()); }
isl_ctx *Scop::getIslCtx() const { return IslCtx; }
__isl_give isl_pw_aff *Scop::getPwAff(const SCEV *E, BasicBlock *BB) {
return Affinator.getPwAff(E, BB);
}
__isl_give isl_union_set *Scop::getDomains() const {
isl_union_set *Domain = isl_union_set_empty(getParamSpace());
for (const ScopStmt &Stmt : *this)
Domain = isl_union_set_add_set(Domain, Stmt.getDomain());
return Domain;
}
__isl_give isl_union_map *
Scop::getAccessesOfType(std::function<bool(MemoryAccess &)> Predicate) {
isl_union_map *Accesses = isl_union_map_empty(getParamSpace());
for (ScopStmt &Stmt : *this) {
for (MemoryAccess *MA : Stmt) {
if (!Predicate(*MA))
continue;
isl_set *Domain = Stmt.getDomain();
isl_map *AccessDomain = MA->getAccessRelation();
AccessDomain = isl_map_intersect_domain(AccessDomain, Domain);
Accesses = isl_union_map_add_map(Accesses, AccessDomain);
}
}
return isl_union_map_coalesce(Accesses);
}
__isl_give isl_union_map *Scop::getMustWrites() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isMustWrite(); });
}
__isl_give isl_union_map *Scop::getMayWrites() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isMayWrite(); });
}
__isl_give isl_union_map *Scop::getWrites() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isWrite(); });
}
__isl_give isl_union_map *Scop::getReads() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isRead(); });
}
__isl_give isl_union_map *Scop::getAccesses() {
return getAccessesOfType([](MemoryAccess &MA) { return true; });
}
__isl_give isl_union_map *Scop::getSchedule() const {
auto Tree = getScheduleTree();
auto S = isl_schedule_get_map(Tree);
isl_schedule_free(Tree);
return S;
}
__isl_give isl_schedule *Scop::getScheduleTree() const {
return isl_schedule_intersect_domain(isl_schedule_copy(Schedule),
getDomains());
}
void Scop::setSchedule(__isl_take isl_union_map *NewSchedule) {
auto *S = isl_schedule_from_domain(getDomains());
S = isl_schedule_insert_partial_schedule(
S, isl_multi_union_pw_aff_from_union_map(NewSchedule));
isl_schedule_free(Schedule);
Schedule = S;
}
void Scop::setScheduleTree(__isl_take isl_schedule *NewSchedule) {
isl_schedule_free(Schedule);
Schedule = NewSchedule;
}
bool Scop::restrictDomains(__isl_take isl_union_set *Domain) {
bool Changed = false;
for (ScopStmt &Stmt : *this) {
isl_union_set *StmtDomain = isl_union_set_from_set(Stmt.getDomain());
isl_union_set *NewStmtDomain = isl_union_set_intersect(
isl_union_set_copy(StmtDomain), isl_union_set_copy(Domain));
if (isl_union_set_is_subset(StmtDomain, NewStmtDomain)) {
isl_union_set_free(StmtDomain);
isl_union_set_free(NewStmtDomain);
continue;
}
Changed = true;
isl_union_set_free(StmtDomain);
NewStmtDomain = isl_union_set_coalesce(NewStmtDomain);
if (isl_union_set_is_empty(NewStmtDomain)) {
Stmt.restrictDomain(isl_set_empty(Stmt.getDomainSpace()));
isl_union_set_free(NewStmtDomain);
} else
Stmt.restrictDomain(isl_set_from_union_set(NewStmtDomain));
}
isl_union_set_free(Domain);
return Changed;
}
ScalarEvolution *Scop::getSE() const { return SE; }
bool Scop::isIgnored(RegionNode *RN) {
BasicBlock *BB = getRegionNodeBasicBlock(RN);
ScopStmt *Stmt = getStmtForRegionNode(RN);
// If there is no stmt, then it already has been removed.
if (!Stmt)
return true;
// Check if there are accesses contained.
if (Stmt->isEmpty())
return true;
// Check for reachability via non-error blocks.
if (!DomainMap.count(BB))
return true;
// Check if error blocks are contained.
if (containsErrorBlock(RN, getRegion(), LI, DT))
return true;
return false;
}
struct MapToDimensionDataTy {
int N;
isl_union_pw_multi_aff *Res;
};
// @brief Create a function that maps the elements of 'Set' to its N-th
// dimension and add it to User->Res.
//
// @param Set The input set.
// @param User->N The dimension to map to.
// @param User->Res The isl_union_pw_multi_aff to which to add the result.
//
// @returns isl_stat_ok if no error occured, othewise isl_stat_error.
static isl_stat mapToDimension_AddSet(__isl_take isl_set *Set, void *User) {
struct MapToDimensionDataTy *Data = (struct MapToDimensionDataTy *)User;
int Dim;
isl_space *Space;
isl_pw_multi_aff *PMA;
Dim = isl_set_dim(Set, isl_dim_set);
Space = isl_set_get_space(Set);
PMA = isl_pw_multi_aff_project_out_map(Space, isl_dim_set, Data->N,
Dim - Data->N);
if (Data->N > 1)
PMA = isl_pw_multi_aff_drop_dims(PMA, isl_dim_out, 0, Data->N - 1);
Data->Res = isl_union_pw_multi_aff_add_pw_multi_aff(Data->Res, PMA);
isl_set_free(Set);
return isl_stat_ok;
}
// @brief Create an isl_multi_union_aff that defines an identity mapping
// from the elements of USet to their N-th dimension.
//
// # Example:
//
// Domain: { A[i,j]; B[i,j,k] }
// N: 1
//
// Resulting Mapping: { {A[i,j] -> [(j)]; B[i,j,k] -> [(j)] }
//
// @param USet A union set describing the elements for which to generate a
// mapping.
// @param N The dimension to map to.
// @returns A mapping from USet to its N-th dimension.
static __isl_give isl_multi_union_pw_aff *
mapToDimension(__isl_take isl_union_set *USet, int N) {
assert(N >= 0);
assert(USet);
assert(!isl_union_set_is_empty(USet));
struct MapToDimensionDataTy Data;
auto *Space = isl_union_set_get_space(USet);
auto *PwAff = isl_union_pw_multi_aff_empty(Space);
Data = {N, PwAff};
auto Res = isl_union_set_foreach_set(USet, &mapToDimension_AddSet, &Data);
(void)Res;
assert(Res == isl_stat_ok);
isl_union_set_free(USet);
return isl_multi_union_pw_aff_from_union_pw_multi_aff(Data.Res);
}
void Scop::addScopStmt(BasicBlock *BB, Region *R) {
if (BB) {
Stmts.emplace_back(*this, *BB);
auto Stmt = &Stmts.back();
StmtMap[BB] = Stmt;
} else {
assert(R && "Either basic block or a region expected.");
Stmts.emplace_back(*this, *R);
auto Stmt = &Stmts.back();
for (BasicBlock *BB : R->blocks())
StmtMap[BB] = Stmt;
}
}
void Scop::buildSchedule() {
Loop *L = getLoopSurroundingRegion(getRegion(), LI);
LoopStackTy LoopStack({LoopStackElementTy(L, nullptr, 0)});
buildSchedule(getRegion().getNode(), LoopStack);
assert(LoopStack.size() == 1 && LoopStack.back().L == L);
Schedule = LoopStack[0].Schedule;
}
/// To generate a schedule for the elements in a Region we traverse the Region
/// in reverse-post-order and add the contained RegionNodes in traversal order
/// to the schedule of the loop that is currently at the top of the LoopStack.
/// For loop-free codes, this results in a correct sequential ordering.
///
/// Example:
/// bb1(0)
/// / \.
/// bb2(1) bb3(2)
/// \ / \.
/// bb4(3) bb5(4)
/// \ /
/// bb6(5)
///
/// Including loops requires additional processing. Whenever a loop header is
/// encountered, the corresponding loop is added to the @p LoopStack. Starting
/// from an empty schedule, we first process all RegionNodes that are within
/// this loop and complete the sequential schedule at this loop-level before
/// processing about any other nodes. To implement this
/// loop-nodes-first-processing, the reverse post-order traversal is
/// insufficient. Hence, we additionally check if the traversal yields
/// sub-regions or blocks that are outside the last loop on the @p LoopStack.
/// These region-nodes are then queue and only traverse after the all nodes
/// within the current loop have been processed.
void Scop::buildSchedule(Region *R, LoopStackTy &LoopStack) {
Loop *OuterScopLoop = getLoopSurroundingRegion(getRegion(), LI);
ReversePostOrderTraversal<Region *> RTraversal(R);
std::deque<RegionNode *> WorkList(RTraversal.begin(), RTraversal.end());
std::deque<RegionNode *> DelayList;
bool LastRNWaiting = false;
// Iterate over the region @p R in reverse post-order but queue
// sub-regions/blocks iff they are not part of the last encountered but not
// completely traversed loop. The variable LastRNWaiting is a flag to indicate
// that we queued the last sub-region/block from the reverse post-order
// iterator. If it is set we have to explore the next sub-region/block from
// the iterator (if any) to guarantee progress. If it is not set we first try
// the next queued sub-region/blocks.
while (!WorkList.empty() || !DelayList.empty()) {
RegionNode *RN;
if ((LastRNWaiting && !WorkList.empty()) || DelayList.size() == 0) {
RN = WorkList.front();
WorkList.pop_front();
LastRNWaiting = false;
} else {
RN = DelayList.front();
DelayList.pop_front();
}
Loop *L = getRegionNodeLoop(RN, LI);
if (!getRegion().contains(L))
L = OuterScopLoop;
Loop *LastLoop = LoopStack.back().L;
if (LastLoop != L) {
if (!LastLoop->contains(L)) {
LastRNWaiting = true;
DelayList.push_back(RN);
continue;
}
LoopStack.push_back({L, nullptr, 0});
}
buildSchedule(RN, LoopStack);
}
return;
}
void Scop::buildSchedule(RegionNode *RN, LoopStackTy &LoopStack) {
if (RN->isSubRegion()) {
auto *LocalRegion = RN->getNodeAs<Region>();
if (!SD.isNonAffineSubRegion(LocalRegion, &getRegion())) {
buildSchedule(LocalRegion, LoopStack);
return;
}
}
auto &LoopData = LoopStack.back();
LoopData.NumBlocksProcessed += getNumBlocksInRegionNode(RN);
if (auto *Stmt = getStmtForRegionNode(RN)) {
auto *UDomain = isl_union_set_from_set(Stmt->getDomain());
auto *StmtSchedule = isl_schedule_from_domain(UDomain);
LoopData.Schedule = combineInSequence(LoopData.Schedule, StmtSchedule);
}
// Check if we just processed the last node in this loop. If we did, finalize
// the loop by:
//
// - adding new schedule dimensions
// - folding the resulting schedule into the parent loop schedule
// - dropping the loop schedule from the LoopStack.
//
// Then continue to check surrounding loops, which might also have been
// completed by this node.
while (LoopData.L &&
LoopData.NumBlocksProcessed == LoopData.L->getNumBlocks()) {
auto Schedule = LoopData.Schedule;
auto NumBlocksProcessed = LoopData.NumBlocksProcessed;
LoopStack.pop_back();
auto &NextLoopData = LoopStack.back();
if (Schedule) {
auto *Domain = isl_schedule_get_domain(Schedule);
auto *MUPA = mapToDimension(Domain, LoopStack.size());
Schedule = isl_schedule_insert_partial_schedule(Schedule, MUPA);
NextLoopData.Schedule =
combineInSequence(NextLoopData.Schedule, Schedule);
}
NextLoopData.NumBlocksProcessed += NumBlocksProcessed;
LoopData = NextLoopData;
}
}
ScopStmt *Scop::getStmtForBasicBlock(BasicBlock *BB) const {
auto StmtMapIt = StmtMap.find(BB);
if (StmtMapIt == StmtMap.end())
return nullptr;
return StmtMapIt->second;
}
ScopStmt *Scop::getStmtForRegionNode(RegionNode *RN) const {
return getStmtForBasicBlock(getRegionNodeBasicBlock(RN));
}
int Scop::getRelativeLoopDepth(const Loop *L) const {
Loop *OuterLoop =
L ? R.outermostLoopInRegion(const_cast<Loop *>(L)) : nullptr;
if (!OuterLoop)
return -1;
return L->getLoopDepth() - OuterLoop->getLoopDepth();
}
void ScopInfo::buildPHIAccesses(PHINode *PHI, Region &R,
Region *NonAffineSubRegion, bool IsExitBlock) {
// PHI nodes that are in the exit block of the region, hence if IsExitBlock is
// true, are not modeled as ordinary PHI nodes as they are not part of the
// region. However, we model the operands in the predecessor blocks that are
// part of the region as regular scalar accesses.
// If we can synthesize a PHI we can skip it, however only if it is in
// the region. If it is not it can only be in the exit block of the region.
// In this case we model the operands but not the PHI itself.
if (!IsExitBlock && canSynthesize(PHI, LI, SE, &R))
return;
// PHI nodes are modeled as if they had been demoted prior to the SCoP
// detection. Hence, the PHI is a load of a new memory location in which the
// incoming value was written at the end of the incoming basic block.
bool OnlyNonAffineSubRegionOperands = true;
for (unsigned u = 0; u < PHI->getNumIncomingValues(); u++) {
Value *Op = PHI->getIncomingValue(u);
BasicBlock *OpBB = PHI->getIncomingBlock(u);
// Do not build scalar dependences inside a non-affine subregion.
if (NonAffineSubRegion && NonAffineSubRegion->contains(OpBB))
continue;
OnlyNonAffineSubRegionOperands = false;
if (!R.contains(OpBB))
continue;
Instruction *OpI = dyn_cast<Instruction>(Op);
if (OpI) {
BasicBlock *OpIBB = OpI->getParent();
// As we pretend there is a use (or more precise a write) of OpI in OpBB
// we have to insert a scalar dependence from the definition of OpI to
// OpBB if the definition is not in OpBB.
if (scop->getStmtForBasicBlock(OpIBB) !=
scop->getStmtForBasicBlock(OpBB)) {
addValueReadAccess(OpI, PHI, OpBB);
addValueWriteAccess(OpI);
}
} else if (ModelReadOnlyScalars && !isa<Constant>(Op)) {
addValueReadAccess(Op, PHI, OpBB);
}
addPHIWriteAccess(PHI, OpBB, Op, IsExitBlock);
}
if (!OnlyNonAffineSubRegionOperands && !IsExitBlock) {
addPHIReadAccess(PHI);
}
}
bool ScopInfo::buildScalarDependences(Instruction *Inst, Region *R,
Region *NonAffineSubRegion) {
bool canSynthesizeInst = canSynthesize(Inst, LI, SE, R);
if (isIgnoredIntrinsic(Inst))
return false;
bool AnyCrossStmtUse = false;
BasicBlock *ParentBB = Inst->getParent();
for (User *U : Inst->users()) {
Instruction *UI = dyn_cast<Instruction>(U);
// Ignore the strange user
if (UI == 0)
continue;
BasicBlock *UseParent = UI->getParent();
// Ignore basic block local uses. A value that is defined in a scop, but
// used in a PHI node in the same basic block does not count as basic block
// local, as for such cases a control flow edge is passed between definition
// and use.
if (UseParent == ParentBB && !isa<PHINode>(UI))
continue;
// Uses by PHI nodes in the entry node count as external uses in case the
// use is through an incoming block that is itself not contained in the
// region.
if (R->getEntry() == UseParent) {
if (auto *PHI = dyn_cast<PHINode>(UI)) {
bool ExternalUse = false;
for (unsigned i = 0; i < PHI->getNumIncomingValues(); i++) {
if (PHI->getIncomingValue(i) == Inst &&
!R->contains(PHI->getIncomingBlock(i))) {
ExternalUse = true;
break;
}
}
if (ExternalUse) {
AnyCrossStmtUse = true;
continue;
}
}
}
// Do not build scalar dependences inside a non-affine subregion.
if (NonAffineSubRegion && NonAffineSubRegion->contains(UseParent))
continue;
// Check for PHI nodes in the region exit and skip them, if they will be
// modeled as PHI nodes.
//
// PHI nodes in the region exit that have more than two incoming edges need
// to be modeled as PHI-Nodes to correctly model the fact that depending on
// the control flow a different value will be assigned to the PHI node. In
// case this is the case, there is no need to create an additional normal
// scalar dependence. Hence, bail out before we register an "out-of-region"
// use for this definition.
if (isa<PHINode>(UI) && UI->getParent() == R->getExit() &&
!R->getExitingBlock())
continue;
// Check whether or not the use is in the SCoP.
if (!R->contains(UseParent)) {
AnyCrossStmtUse = true;
continue;
}
// If the instruction can be synthesized and the user is in the region
// we do not need to add scalar dependences.
if (canSynthesizeInst)
continue;
// No need to translate these scalar dependences into polyhedral form,
// because synthesizable scalars can be generated by the code generator.
if (canSynthesize(UI, LI, SE, R))
continue;
// Skip PHI nodes in the region as they handle their operands on their own.
if (isa<PHINode>(UI))
continue;
// Now U is used in another statement.
AnyCrossStmtUse = true;
// Do not build a read access that is not in the current SCoP
// Use the def instruction as base address of the MemoryAccess, so that it
// will become the name of the scalar access in the polyhedral form.
addValueReadAccess(Inst, UI);
}
if (ModelReadOnlyScalars && !isa<PHINode>(Inst)) {
for (Value *Op : Inst->operands()) {
if (canSynthesize(Op, LI, SE, R))
continue;
if (Instruction *OpInst = dyn_cast<Instruction>(Op))
if (R->contains(OpInst))
continue;
if (isa<Constant>(Op))
continue;
addValueReadAccess(Op, Inst);
}
}
return AnyCrossStmtUse;
}
extern MapInsnToMemAcc InsnToMemAcc;
void ScopInfo::buildMemoryAccess(
Instruction *Inst, Loop *L, Region *R,
const ScopDetection::BoxedLoopsSetTy *BoxedLoops,
const InvariantLoadsSetTy &ScopRIL) {
unsigned Size;
Type *SizeType;
Value *Val;
enum MemoryAccess::AccessType Type;
if (LoadInst *Load = dyn_cast<LoadInst>(Inst)) {
SizeType = Load->getType();
Size = TD->getTypeAllocSize(SizeType);
Type = MemoryAccess::READ;
Val = Load;
} else {
StoreInst *Store = cast<StoreInst>(Inst);
SizeType = Store->getValueOperand()->getType();
Size = TD->getTypeAllocSize(SizeType);
Type = MemoryAccess::MUST_WRITE;
Val = Store->getValueOperand();
}
auto Address = getPointerOperand(*Inst);
const SCEV *AccessFunction = SE->getSCEVAtScope(Address, L);
const SCEVUnknown *BasePointer =
dyn_cast<SCEVUnknown>(SE->getPointerBase(AccessFunction));
assert(BasePointer && "Could not find base pointer");
AccessFunction = SE->getMinusSCEV(AccessFunction, BasePointer);
if (isa<GetElementPtrInst>(Address) || isa<BitCastInst>(Address)) {
auto NewAddress = Address;
if (auto *BitCast = dyn_cast<BitCastInst>(Address)) {
auto Src = BitCast->getOperand(0);
auto SrcTy = Src->getType();
auto DstTy = BitCast->getType();
if (SrcTy->getPrimitiveSizeInBits() == DstTy->getPrimitiveSizeInBits())
NewAddress = Src;
}
if (auto *GEP = dyn_cast<GetElementPtrInst>(NewAddress)) {
std::vector<const SCEV *> Subscripts;
std::vector<int> Sizes;
std::tie(Subscripts, Sizes) = getIndexExpressionsFromGEP(GEP, *SE);
auto BasePtr = GEP->getOperand(0);
std::vector<const SCEV *> SizesSCEV;
bool AllAffineSubcripts = true;
for (auto Subscript : Subscripts) {
InvariantLoadsSetTy AccessILS;
AllAffineSubcripts =
isAffineExpr(R, Subscript, *SE, nullptr, &AccessILS);
for (LoadInst *LInst : AccessILS)
if (!ScopRIL.count(LInst))
AllAffineSubcripts = false;
if (!AllAffineSubcripts)
break;
}
if (AllAffineSubcripts && Sizes.size() > 0) {
for (auto V : Sizes)
SizesSCEV.push_back(SE->getSCEV(ConstantInt::get(
IntegerType::getInt64Ty(BasePtr->getContext()), V)));
SizesSCEV.push_back(SE->getSCEV(ConstantInt::get(
IntegerType::getInt64Ty(BasePtr->getContext()), Size)));
addArrayAccess(Inst, Type, BasePointer->getValue(), Size, true,
Subscripts, SizesSCEV, Val);
return;
}
}
}
auto AccItr = InsnToMemAcc.find(Inst);
if (PollyDelinearize && AccItr != InsnToMemAcc.end()) {
addArrayAccess(Inst, Type, BasePointer->getValue(), Size, true,
AccItr->second.DelinearizedSubscripts,
AccItr->second.Shape->DelinearizedSizes, Val);
return;
}
// Check if the access depends on a loop contained in a non-affine subregion.
bool isVariantInNonAffineLoop = false;
if (BoxedLoops) {
SetVector<const Loop *> Loops;
findLoops(AccessFunction, Loops);
for (const Loop *L : Loops)
if (BoxedLoops->count(L))
isVariantInNonAffineLoop = true;
}
InvariantLoadsSetTy AccessILS;
bool IsAffine =
!isVariantInNonAffineLoop &&
isAffineExpr(R, AccessFunction, *SE, BasePointer->getValue(), &AccessILS);
for (LoadInst *LInst : AccessILS)
if (!ScopRIL.count(LInst))
IsAffine = false;
// FIXME: Size of the number of bytes of an array element, not the number of
// elements as probably intended here.
const SCEV *SizeSCEV =
SE->getConstant(TD->getIntPtrType(Inst->getContext()), Size);
if (!IsAffine && Type == MemoryAccess::MUST_WRITE)
Type = MemoryAccess::MAY_WRITE;
addArrayAccess(Inst, Type, BasePointer->getValue(), Size, IsAffine,
ArrayRef<const SCEV *>(AccessFunction),
ArrayRef<const SCEV *>(SizeSCEV), Val);
}
void ScopInfo::buildAccessFunctions(Region &R, Region &SR) {
if (SD->isNonAffineSubRegion(&SR, &R)) {
for (BasicBlock *BB : SR.blocks())
buildAccessFunctions(R, *BB, &SR);
return;
}
for (auto I = SR.element_begin(), E = SR.element_end(); I != E; ++I)
if (I->isSubRegion())
buildAccessFunctions(R, *I->getNodeAs<Region>());
else
buildAccessFunctions(R, *I->getNodeAs<BasicBlock>());
}
void ScopInfo::buildStmts(Region &SR) {
Region *R = getRegion();
if (SD->isNonAffineSubRegion(&SR, R)) {
scop->addScopStmt(nullptr, &SR);
return;
}
for (auto I = SR.element_begin(), E = SR.element_end(); I != E; ++I)
if (I->isSubRegion())
buildStmts(*I->getNodeAs<Region>());
else
scop->addScopStmt(I->getNodeAs<BasicBlock>(), nullptr);
}
void ScopInfo::buildAccessFunctions(Region &R, BasicBlock &BB,
Region *NonAffineSubRegion,
bool IsExitBlock) {
// We do not build access functions for error blocks, as they may contain
// instructions we can not model.
DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
if (isErrorBlock(BB, R, *LI, DT) && !IsExitBlock)
return;
Loop *L = LI->getLoopFor(&BB);
// The set of loops contained in non-affine subregions that are part of R.
const ScopDetection::BoxedLoopsSetTy *BoxedLoops = SD->getBoxedLoops(&R);
// The set of loads that are required to be invariant.
auto &ScopRIL = *SD->getRequiredInvariantLoads(&R);
for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I) {
Instruction *Inst = &*I;
PHINode *PHI = dyn_cast<PHINode>(Inst);
if (PHI)
buildPHIAccesses(PHI, R, NonAffineSubRegion, IsExitBlock);
// For the exit block we stop modeling after the last PHI node.
if (!PHI && IsExitBlock)
break;
// TODO: At this point we only know that elements of ScopRIL have to be
// invariant and will be hoisted for the SCoP to be processed. Though,
// there might be other invariant accesses that will be hoisted and
// that would allow to make a non-affine access affine.
if (isa<LoadInst>(Inst) || isa<StoreInst>(Inst))
buildMemoryAccess(Inst, L, &R, BoxedLoops, ScopRIL);
if (isIgnoredIntrinsic(Inst))
continue;
// Do not build scalar dependences for required invariant loads as we will
// hoist them later on anyway or drop the SCoP if we cannot.
if (ScopRIL.count(dyn_cast<LoadInst>(Inst)))
continue;
if (buildScalarDependences(Inst, &R, NonAffineSubRegion)) {
if (!isa<StoreInst>(Inst))
addValueWriteAccess(Inst);
}
}
}
void ScopInfo::addMemoryAccess(BasicBlock *BB, Instruction *Inst,
MemoryAccess::AccessType Type,
Value *BaseAddress, unsigned ElemBytes,
bool Affine, Value *AccessValue,
ArrayRef<const SCEV *> Subscripts,
ArrayRef<const SCEV *> Sizes,
ScopArrayInfo::MemoryKind Kind) {
ScopStmt *Stmt = scop->getStmtForBasicBlock(BB);
// Do not create a memory access for anything not in the SCoP. It would be
// ignored anyway.
if (!Stmt)
return;
AccFuncSetType &AccList = AccFuncMap[BB];
Value *BaseAddr = BaseAddress;
std::string BaseName = getIslCompatibleName("MemRef_", BaseAddr, "");
bool isKnownMustAccess = false;
// Accesses in single-basic block statements are always excuted.
if (Stmt->isBlockStmt())
isKnownMustAccess = true;
if (Stmt->isRegionStmt()) {
// Accesses that dominate the exit block of a non-affine region are always
// executed. In non-affine regions there may exist MK_Values that do not
// dominate the exit. MK_Values will always dominate the exit and MK_PHIs
// only if there is at most one PHI_WRITE in the non-affine region.
if (DT->dominates(BB, Stmt->getRegion()->getExit()))
isKnownMustAccess = true;
}
if (!isKnownMustAccess && Type == MemoryAccess::MUST_WRITE)
Type = MemoryAccess::MAY_WRITE;
AccList.emplace_back(Stmt, Inst, Type, BaseAddress, ElemBytes, Affine,
Subscripts, Sizes, AccessValue, Kind, BaseName);
Stmt->addAccess(&AccList.back());
}
void ScopInfo::addArrayAccess(Instruction *MemAccInst,
MemoryAccess::AccessType Type, Value *BaseAddress,
unsigned ElemBytes, bool IsAffine,
ArrayRef<const SCEV *> Subscripts,
ArrayRef<const SCEV *> Sizes,
Value *AccessValue) {
assert(isa<LoadInst>(MemAccInst) || isa<StoreInst>(MemAccInst));
assert(isa<LoadInst>(MemAccInst) == (Type == MemoryAccess::READ));
addMemoryAccess(MemAccInst->getParent(), MemAccInst, Type, BaseAddress,
ElemBytes, IsAffine, AccessValue, Subscripts, Sizes,
ScopArrayInfo::MK_Array);
}
void ScopInfo::addValueWriteAccess(Instruction *Value) {
addMemoryAccess(Value->getParent(), Value, MemoryAccess::MUST_WRITE, Value, 1,
true, Value, ArrayRef<const SCEV *>(),
ArrayRef<const SCEV *>(), ScopArrayInfo::MK_Value);
}
void ScopInfo::addValueReadAccess(Value *Value, Instruction *User) {
assert(!isa<PHINode>(User));
addMemoryAccess(User->getParent(), User, MemoryAccess::READ, Value, 1, true,
Value, ArrayRef<const SCEV *>(), ArrayRef<const SCEV *>(),
ScopArrayInfo::MK_Value);
}
void ScopInfo::addValueReadAccess(Value *Value, PHINode *User,
BasicBlock *UserBB) {
addMemoryAccess(UserBB, User, MemoryAccess::READ, Value, 1, true, Value,
ArrayRef<const SCEV *>(), ArrayRef<const SCEV *>(),
ScopArrayInfo::MK_Value);
}
void ScopInfo::addPHIWriteAccess(PHINode *PHI, BasicBlock *IncomingBlock,
Value *IncomingValue, bool IsExitBlock) {
addMemoryAccess(IncomingBlock, IncomingBlock->getTerminator(),
MemoryAccess::MUST_WRITE, PHI, 1, true, IncomingValue,
ArrayRef<const SCEV *>(), ArrayRef<const SCEV *>(),
IsExitBlock ? ScopArrayInfo::MK_ExitPHI
: ScopArrayInfo::MK_PHI);
}
void ScopInfo::addPHIReadAccess(PHINode *PHI) {
addMemoryAccess(PHI->getParent(), PHI, MemoryAccess::READ, PHI, 1, true, PHI,
ArrayRef<const SCEV *>(), ArrayRef<const SCEV *>(),
ScopArrayInfo::MK_PHI);
}
void ScopInfo::buildScop(Region &R, AssumptionCache &AC) {
unsigned MaxLoopDepth = getMaxLoopDepthInRegion(R, *LI, *SD);
scop = new Scop(R, AccFuncMap, *SD, *SE, *DT, *LI, ctx, MaxLoopDepth);
buildStmts(R);
buildAccessFunctions(R, R);
// In case the region does not have an exiting block we will later (during
// code generation) split the exit block. This will move potential PHI nodes
// from the current exit block into the new region exiting block. Hence, PHI
// nodes that are at this point not part of the region will be.
// To handle these PHI nodes later we will now model their operands as scalar
// accesses. Note that we do not model anything in the exit block if we have
// an exiting block in the region, as there will not be any splitting later.
if (!R.getExitingBlock())
buildAccessFunctions(R, *R.getExit(), nullptr, /* IsExitBlock */ true);
scop->init(*AA, AC);
}
void ScopInfo::print(raw_ostream &OS, const Module *) const {
if (!scop) {
OS << "Invalid Scop!\n";
return;
}
scop->print(OS);
}
void ScopInfo::clear() {
AccFuncMap.clear();
if (scop) {
delete scop;
scop = 0;
}
}
//===----------------------------------------------------------------------===//
ScopInfo::ScopInfo() : RegionPass(ID), scop(0) {
ctx = isl_ctx_alloc();
isl_options_set_on_error(ctx, ISL_ON_ERROR_ABORT);
}
ScopInfo::~ScopInfo() {
clear();
isl_ctx_free(ctx);
}
void ScopInfo::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LoopInfoWrapperPass>();
AU.addRequired<RegionInfoPass>();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequiredTransitive<ScalarEvolutionWrapperPass>();
AU.addRequiredTransitive<ScopDetection>();
AU.addRequired<AAResultsWrapperPass>();
AU.addRequired<AssumptionCacheTracker>();
AU.setPreservesAll();
}
bool ScopInfo::runOnRegion(Region *R, RGPassManager &RGM) {
SD = &getAnalysis<ScopDetection>();
if (!SD->isMaxRegionInScop(*R))
return false;
Function *F = R->getEntry()->getParent();
SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
TD = &F->getParent()->getDataLayout();
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(*F);
DebugLoc Beg, End;
getDebugLocations(R, Beg, End);
std::string Msg = "SCoP begins here.";
emitOptimizationRemarkAnalysis(F->getContext(), DEBUG_TYPE, *F, Beg, Msg);
buildScop(*R, AC);
DEBUG(scop->print(dbgs()));
if (scop->isEmpty() || !scop->hasFeasibleRuntimeContext()) {
Msg = "SCoP ends here but was dismissed.";
delete scop;
scop = nullptr;
} else {
Msg = "SCoP ends here.";
++ScopFound;
if (scop->getMaxLoopDepth() > 0)
++RichScopFound;
}
emitOptimizationRemarkAnalysis(F->getContext(), DEBUG_TYPE, *F, End, Msg);
return false;
}
char ScopInfo::ID = 0;
Pass *polly::createScopInfoPass() { return new ScopInfo(); }
INITIALIZE_PASS_BEGIN(ScopInfo, "polly-scops",
"Polly - Create polyhedral description of Scops", false,
false);
INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass);
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker);
INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
INITIALIZE_PASS_DEPENDENCY(RegionInfoPass);
INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass);
INITIALIZE_PASS_DEPENDENCY(ScopDetection);
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass);
INITIALIZE_PASS_END(ScopInfo, "polly-scops",
"Polly - Create polyhedral description of Scops", false,
false)