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

3359 lines
115 KiB
C++

//===--------- 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/LinkAllPasses.h"
#include "polly/CodeGen/BlockGenerators.h"
#include "polly/Options.h"
#include "polly/ScopInfo.h"
#include "polly/Support/GICHelper.h"
#include "polly/Support/SCEVValidator.h"
#include "polly/Support/ScopHelper.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/LoopInfo.h"
#include "llvm/Analysis/LoopIterator.h"
#include "llvm/Analysis/RegionIterator.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.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");
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));
//===----------------------------------------------------------------------===//
/// Helper Classes
void Comparison::print(raw_ostream &OS) const {
// Not yet implemented.
}
// 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::ScopArrayInfo(Value *BasePtr, Type *ElementType, isl_ctx *Ctx,
ArrayRef<const SCEV *> Sizes, bool IsPHI, Scop *S)
: BasePtr(BasePtr), ElementType(ElementType), IsPHI(IsPHI), S(*S) {
std::string BasePtrName =
getIslCompatibleName("MemRef_", BasePtr, IsPHI ? "__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;
}
void ScopArrayInfo::updateSizes(ArrayRef<const SCEV *> NewSizes) {
#ifndef NDEBUG
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++) {
assert(NewSizes[i + ExtraDimsNew] == DimensionSizes[i + ExtraDimsOld] &&
"Array update with non-matching dimension sizes");
}
#endif
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);
}
}
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 ElementType->getPrimitiveSizeInBits() / 8;
}
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() << "[*]";
for (unsigned u = 0; u < getNumberOfDimensions(); u++) {
OS << "[";
if (SizeAsPwAff)
OS << " " << DimensionSizesPw[u] << " ";
else
OS << *DimensionSizes[u];
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);
}
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 = Subscripts.size(); 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 = Statement->getPwAff(Sizes[i - 1]);
SizeE = isl_pw_aff_drop_dims(SizeE, isl_dim_in, 0,
Statement->getNumIterators());
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(Outside);
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;
}
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;
}
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.
isl_val *v = isl_val_int_from_si(Ctx, getElemSizeInBytes());
Affine = isl_pw_aff_scale_down_val(Affine, v);
}
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);
assumeNoOutOfBound();
AccessRelation = isl_map_gist_domain(AccessRelation, Statement->getDomain());
isl_space_free(Space);
}
MemoryAccess::MemoryAccess(Instruction *AccessInst, __isl_take isl_id *Id,
AccessType Type, Value *BaseAddress,
unsigned ElemBytes, bool Affine,
ArrayRef<const SCEV *> Subscripts,
ArrayRef<const SCEV *> Sizes, Value *AccessValue,
AccessOrigin Origin, StringRef BaseName)
: Id(Id), Origin(Origin), AccType(Type), RedType(RT_NONE),
Statement(nullptr), 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) {}
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: " << isImplicit() << "]\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::buildAccesses(BasicBlock *Block, bool isApproximated) {
AccFuncSetType *AFS = Parent.getAccessFunctions(Block);
if (!AFS)
return;
for (auto &Access : *AFS) {
Instruction *AccessInst = Access.getAccessInstruction();
Type *ElementType = Access.getAccessValue()->getType();
const ScopArrayInfo *SAI = getParent()->getOrCreateScopArrayInfo(
Access.getBaseAddr(), ElementType, Access.Sizes, Access.isPHI());
if (isApproximated && Access.isMustWrite())
Access.AccType = MemoryAccess::MAY_WRITE;
MemoryAccessList *&MAL = InstructionToAccess[AccessInst];
if (!MAL)
MAL = new MemoryAccessList();
Access.setStatement(this);
Access.buildAccessRelation(SAI);
MAL->emplace_front(&Access);
MemAccs.push_back(MAL->front());
}
}
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 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");
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 {
auto *ICond = dyn_cast<ICmpInst>(Condition);
assert(ICond &&
"Condition of exiting branch was neither constant nor ICmp!");
ScalarEvolution &SE = *S.getSE();
BasicBlock *BB = TI->getParent();
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);
}
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))));
}
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();
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];
if (!isAffineExpr(&Parent.getRegion(), Expr, SE))
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);
Parent.addAssumption(InBoundIfExecuted);
}
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), BB(nullptr), R(&R), Build(nullptr) {
BaseName = getIslCompatibleName("Stmt_", R.getNameStr(), "");
buildDomain();
collectSurroundingLoops();
BasicBlock *EntryBB = R.getEntry();
for (BasicBlock *Block : R.blocks()) {
buildAccesses(Block, Block != EntryBB);
deriveAssumptions(Block);
}
if (DetectReductions)
checkForReductions();
}
ScopStmt::ScopStmt(Scop &parent, BasicBlock &bb)
: Parent(parent), BB(&bb), R(nullptr), Build(nullptr) {
BaseName = getIslCompatibleName("Stmt_", &bb, "");
buildDomain();
collectSurroundingLoops();
buildAccesses(BB);
deriveAssumptions(BB);
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(lookupAccessFor(PossibleLoad0));
if (PossibleLoad1 && PossibleLoad1->getNumUses() == 1)
if (PossibleLoad1->getParent() == Store->getParent())
Loads.push_back(lookupAccessFor(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() {
DeleteContainerSeconds(InstructionToAccess);
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::hoistMemoryAccesses(MemoryAccessList &InvMAs,
InvariantAccessesTy &TargetList) {
// Remove all memory accesses in @p InvMAs from this statement together
// with all scalar accesses that were caused by them. The tricky iteration
// order uses is needed because the MemAccs is a vector and the order in
// which the accesses of each memory access list (MAL) are stored in this
// vector is reversed.
for (MemoryAccess *MA : InvMAs) {
auto &MAL = *lookupAccessesFor(MA->getAccessInstruction());
MAL.reverse();
auto MALIt = MAL.begin();
auto MALEnd = MAL.end();
auto MemAccsIt = MemAccs.begin();
while (MALIt != MALEnd) {
while (*MemAccsIt != *MALIt)
MemAccsIt++;
MALIt++;
MemAccs.erase(MemAccsIt);
}
InstructionToAccess.erase(MA->getAccessInstruction());
delete &MAL;
}
// Get the context under which this statement, hence the memory accesses, are
// executed.
isl_set *DomainCtx = isl_set_params(getDomain());
DomainCtx = isl_set_remove_redundancies(DomainCtx);
DomainCtx = isl_set_detect_equalities(DomainCtx);
DomainCtx = isl_set_coalesce(DomainCtx);
for (MemoryAccess *MA : InvMAs)
TargetList.push_back(std::make_pair(MA, isl_set_copy(DomainCtx)));
isl_set_free(DomainCtx);
}
//===----------------------------------------------------------------------===//
/// 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;
}
void Scop::addParams(std::vector<const SCEV *> NewParameters) {
for (const SCEV *Parameter : NewParameters) {
Parameter = extractConstantFactor(Parameter, *SE).second;
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) const {
ParamIdType::const_iterator IdIter = ParameterIds.find(Parameter);
if (IdIter == ParameterIds.end())
return nullptr;
std::string ParameterName;
if (const SCEVUnknown *ValueParameter = dyn_cast<SCEVUnknown>(Parameter)) {
Value *Val = ValueParameter->getValue();
ParameterName = Val->getName();
}
if (ParameterName == "" || ParameterName.substr(0, 2) == "p_")
ParameterName = "p_" + utostr_32(IdIter->second);
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() {
BoundaryContext = Affinator.getWrappingContext();
BoundaryContext = isl_set_complement(BoundaryContext);
BoundaryContext = isl_set_gist_params(BoundaryContext, getContext());
}
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::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) {
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;
unsigned NumBlocks = 0;
Region *R = RN->getNodeAs<Region>();
for (auto BB : R->blocks()) {
(void)BB;
NumBlocks++;
}
return NumBlocks;
}
///}
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::buildDomains(Region *R, LoopInfo &LI, ScopDetection &SD,
DominatorTree &DT) {
auto *EntryBB = R->getEntry();
int LD = getRelativeLoopDepth(LI.getLoopFor(EntryBB));
auto *S = isl_set_universe(isl_space_set_alloc(getIslCtx(), 0, LD + 1));
Loop *L = LI.getLoopFor(EntryBB);
while (LD-- >= 0) {
S = addDomainDimId(S, LD + 1, L);
L = L->getParentLoop();
}
DomainMap[EntryBB] = S;
if (SD.isNonAffineSubRegion(R, R))
return;
buildDomainsWithBranchConstraints(R, LI, SD, DT);
propagateDomainConstraints(R, LI, SD, DT);
}
void Scop::buildDomainsWithBranchConstraints(Region *R, LoopInfo &LI,
ScopDetection &SD,
DominatorTree &DT) {
RegionInfo &RI = *R->getRegionInfo();
// 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, LI, SD, DT);
continue;
}
}
BasicBlock *BB = getRegionNodeBasicBlock(RN);
TerminatorInst *TI = BB->getTerminator();
// Unreachable instructions do not have successors so we can skip them.
if (isa<UnreachableInst>(TI)) {
// Assume unreachables only in error blocks.
assert(isErrorBlock(*BB));
continue;
}
isl_set *Domain = DomainMap[BB];
DEBUG(dbgs() << "\tVisit: " << BB->getName() << " : " << Domain << "\n");
assert(Domain && "Due to reverse post order traversal of the region all "
"predecessor of the current region node should have been "
"visited and a domain for this region node should have "
"been set.");
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);
Region *SuccRegion = RI.getRegionFor(SuccBB);
if (BBLoop != SuccBBLoop && !RN->isSubRegion() &&
!(SD.isNonAffineSubRegion(SuccRegion, &getRegion()) &&
SuccRegion->contains(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);
DEBUG(dbgs() << "\tSet SuccBB: " << SuccBB->getName() << " : " << Domain
<< "\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);
}
static bool containsErrorBlock(RegionNode *RN) {
if (!RN->isSubRegion())
return isErrorBlock(*RN->getNodeAs<BasicBlock>());
for (BasicBlock *BB : RN->getNodeAs<Region>()->blocks())
if (isErrorBlock(*BB))
return true;
return false;
}
void Scop::propagateDomainConstraints(Region *R, LoopInfo &LI,
ScopDetection &SD, DominatorTree &DT) {
// 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, LI, SD, DT);
continue;
}
}
BasicBlock *BB = getRegionNodeBasicBlock(RN);
Loop *BBLoop = getRegionNodeLoop(RN, LI);
int BBLoopDepth = getRelativeLoopDepth(BBLoop);
isl_set *&Domain = DomainMap[BB];
assert(Domain && "Due to reverse post order traversal of the region all "
"predecessor of the current region node should have been "
"visited and a domain for this region node should have "
"been set.");
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, LI);
// Add assumptions for error blocks.
if (containsErrorBlock(RN)) {
IsOptimized = true;
isl_set *DomPar = isl_set_params(isl_set_copy(Domain));
addAssumption(isl_set_complement(DomPar));
}
}
}
/// @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, LoopInfo &LI) {
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) {
assert(DomainMap.count(LatchBB));
isl_set *LatchBBDom = DomainMap[LatchBB];
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(BoundedCtx);
}
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.
addAssumption(isl_set_empty(getParamSpace()));
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->isImplicit())
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);
}
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();) {
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;
}
static Loop *getLoopSurroundingRegion(Region &R, LoopInfo &LI) {
Loop *L = LI.getLoopFor(R.getEntry());
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,
ScalarEvolution &ScalarEvolution, DominatorTree &DT,
isl_ctx *Context, unsigned MaxLoopDepth)
: DT(DT), SE(&ScalarEvolution), R(R), AccFuncMap(AccFuncMap),
IsOptimized(false), HasSingleExitEdge(R.getExitingBlock()),
MaxLoopDepth(MaxLoopDepth), IslCtx(Context), Affinator(this),
BoundaryContext(nullptr) {}
void Scop::init(LoopInfo &LI, ScopDetection &SD, AliasAnalysis &AA) {
buildContext();
buildDomains(&R, LI, SD, DT);
DenseMap<Loop *, std::pair<isl_schedule *, unsigned>> LoopSchedules;
Loop *L = getLoopSurroundingRegion(R, LI);
LoopSchedules[L];
buildSchedule(&R, LI, SD, LoopSchedules);
updateAccessDimensionality();
Schedule = LoopSchedules[L].first;
realignParams();
addParameterBounds();
addUserContext();
buildBoundaryContext();
simplifyContexts();
buildAliasChecks(AA);
hoistInvariantLoads();
simplifySCoP();
}
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 &IA : InvariantAccesses)
isl_set_free(IA.second);
}
void Scop::updateAccessDimensionality() {
for (auto &Stmt : *this)
for (auto &Access : Stmt)
Access->updateDimensionality();
}
void Scop::simplifySCoP() {
for (auto StmtIt = Stmts.begin(), StmtEnd = Stmts.end(); StmtIt != StmtEnd;) {
ScopStmt &Stmt = *StmtIt;
if (!StmtIt->isEmpty()) {
StmtIt++;
continue;
}
if (Stmt.isRegionStmt())
for (BasicBlock *BB : Stmt.getRegion()->blocks())
StmtMap.erase(BB);
else
StmtMap.erase(Stmt.getBasicBlock());
StmtIt = Stmts.erase(StmtIt);
}
}
void Scop::hoistInvariantLoads() {
isl_union_map *Writes = getWrites();
for (ScopStmt &Stmt : *this) {
// 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.
isl_set *Domain = Stmt.getDomain();
MemoryAccessList InvMAs;
for (MemoryAccess *MA : Stmt) {
if (MA->isImplicit() || MA->isWrite() || !MA->isAffine())
continue;
isl_map *AccessRelation = MA->getAccessRelation();
if (isl_map_involves_dims(AccessRelation, isl_dim_in, 0,
Stmt.getNumIterators())) {
isl_map_free(AccessRelation);
continue;
}
AccessRelation =
isl_map_intersect_domain(AccessRelation, isl_set_copy(Domain));
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)
continue;
InvMAs.push_front(MA);
}
// 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.
InvMAs.reverse();
// Transfer the memory access from the statement to the SCoP.
Stmt.hoistMemoryAccesses(InvMAs, InvariantAccesses);
isl_set_free(Domain);
}
isl_union_map_free(Writes);
if (!InvariantAccesses.empty())
IsOptimized = true;
}
const ScopArrayInfo *
Scop::getOrCreateScopArrayInfo(Value *BasePtr, Type *AccessType,
ArrayRef<const SCEV *> Sizes, bool IsPHI) {
auto &SAI = ScopArrayInfoMap[std::make_pair(BasePtr, IsPHI)];
if (!SAI) {
SAI.reset(new ScopArrayInfo(BasePtr, AccessType, getIslCtx(), Sizes, IsPHI,
this));
} else {
if (Sizes.size() > SAI->getNumberOfDimensions())
SAI->updateSizes(Sizes);
}
return SAI.get();
}
const ScopArrayInfo *Scop::getScopArrayInfo(Value *BasePtr, bool IsPHI) {
auto *SAI = ScopArrayInfoMap[std::make_pair(BasePtr, IsPHI)].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;
}
void Scop::addAssumption(__isl_take isl_set *Set) {
AssumedContext = isl_set_intersect(AssumedContext, Set);
AssumedContext = isl_set_coalesce(AssumedContext);
}
__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 &IA : InvariantAccesses) {
IA.first->print(OS);
OS.indent(12) << "Execution Context: " << IA.second << "\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::getMustWrites() {
isl_union_map *Write = isl_union_map_empty(getParamSpace());
for (ScopStmt &Stmt : *this) {
for (MemoryAccess *MA : Stmt) {
if (!MA->isMustWrite())
continue;
isl_set *Domain = Stmt.getDomain();
isl_map *AccessDomain = MA->getAccessRelation();
AccessDomain = isl_map_intersect_domain(AccessDomain, Domain);
Write = isl_union_map_add_map(Write, AccessDomain);
}
}
return isl_union_map_coalesce(Write);
}
__isl_give isl_union_map *Scop::getMayWrites() {
isl_union_map *Write = isl_union_map_empty(getParamSpace());
for (ScopStmt &Stmt : *this) {
for (MemoryAccess *MA : Stmt) {
if (!MA->isMayWrite())
continue;
isl_set *Domain = Stmt.getDomain();
isl_map *AccessDomain = MA->getAccessRelation();
AccessDomain = isl_map_intersect_domain(AccessDomain, Domain);
Write = isl_union_map_add_map(Write, AccessDomain);
}
}
return isl_union_map_coalesce(Write);
}
__isl_give isl_union_map *Scop::getWrites() {
isl_union_map *Write = isl_union_map_empty(getParamSpace());
for (ScopStmt &Stmt : *this) {
for (MemoryAccess *MA : Stmt) {
if (!MA->isWrite())
continue;
isl_set *Domain = Stmt.getDomain();
isl_map *AccessDomain = MA->getAccessRelation();
AccessDomain = isl_map_intersect_domain(AccessDomain, Domain);
Write = isl_union_map_add_map(Write, AccessDomain);
}
}
return isl_union_map_coalesce(Write);
}
__isl_give isl_union_map *Scop::getReads() {
isl_union_map *Read = isl_union_map_empty(getParamSpace());
for (ScopStmt &Stmt : *this) {
for (MemoryAccess *MA : Stmt) {
if (!MA->isRead())
continue;
isl_set *Domain = Stmt.getDomain();
isl_map *AccessDomain = MA->getAccessRelation();
AccessDomain = isl_map_intersect_domain(AccessDomain, Domain);
Read = isl_union_map_add_map(Read, AccessDomain);
}
}
return isl_union_map_coalesce(Read);
}
__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::isTrivialBB(BasicBlock *BB) {
if (getAccessFunctions(BB) && !isErrorBlock(*BB))
return false;
return true;
}
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.
//
// The result is added to 'User->Res'.
//
// @param Set The input set.
// @param N The dimension to map to.
//
// @returns Zero if no error occurred, non-zero otherwise.
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 a function that maps the elements of Domain to their Nth
// dimension.
//
// @param Domain The set of elements to map.
// @param N The dimension to map to.
static __isl_give isl_multi_union_pw_aff *
mapToDimension(__isl_take isl_union_set *Domain, int N) {
if (N <= 0 || isl_union_set_is_empty(Domain)) {
isl_union_set_free(Domain);
return nullptr;
}
struct MapToDimensionDataTy Data;
isl_space *Space;
Space = isl_union_set_get_space(Domain);
Data.N = N;
Data.Res = isl_union_pw_multi_aff_empty(Space);
if (isl_union_set_foreach_set(Domain, &mapToDimension_AddSet, &Data) < 0)
Data.Res = isl_union_pw_multi_aff_free(Data.Res);
isl_union_set_free(Domain);
return isl_multi_union_pw_aff_from_union_pw_multi_aff(Data.Res);
}
ScopStmt *Scop::addScopStmt(BasicBlock *BB, Region *R) {
ScopStmt *Stmt;
if (BB) {
Stmts.emplace_back(*this, *BB);
Stmt = &Stmts.back();
StmtMap[BB] = Stmt;
} else {
assert(R && "Either basic block or a region expected.");
Stmts.emplace_back(*this, *R);
Stmt = &Stmts.back();
for (BasicBlock *BB : R->blocks())
StmtMap[BB] = Stmt;
}
return Stmt;
}
void Scop::buildSchedule(
Region *R, LoopInfo &LI, ScopDetection &SD,
DenseMap<Loop *, std::pair<isl_schedule *, unsigned>> &LoopSchedules) {
if (SD.isNonAffineSubRegion(R, &getRegion())) {
auto *Stmt = addScopStmt(nullptr, R);
auto *UDomain = isl_union_set_from_set(Stmt->getDomain());
auto *StmtSchedule = isl_schedule_from_domain(UDomain);
Loop *L = getLoopSurroundingRegion(*R, LI);
auto &LSchedulePair = LoopSchedules[L];
LSchedulePair.first = StmtSchedule;
return;
}
ReversePostOrderTraversal<Region *> RTraversal(R);
for (auto *RN : RTraversal) {
if (RN->isSubRegion()) {
Region *SubRegion = RN->getNodeAs<Region>();
if (!SD.isNonAffineSubRegion(SubRegion, &getRegion())) {
buildSchedule(SubRegion, LI, SD, LoopSchedules);
continue;
}
}
Loop *L = getRegionNodeLoop(RN, LI);
int LD = getRelativeLoopDepth(L);
auto &LSchedulePair = LoopSchedules[L];
LSchedulePair.second += getNumBlocksInRegionNode(RN);
BasicBlock *BB = getRegionNodeBasicBlock(RN);
if (RN->isSubRegion() || !isTrivialBB(BB)) {
ScopStmt *Stmt;
if (RN->isSubRegion())
Stmt = addScopStmt(nullptr, RN->getNodeAs<Region>());
else
Stmt = addScopStmt(BB, nullptr);
auto *UDomain = isl_union_set_from_set(Stmt->getDomain());
auto *StmtSchedule = isl_schedule_from_domain(UDomain);
LSchedulePair.first =
combineInSequence(LSchedulePair.first, StmtSchedule);
}
unsigned NumVisited = LSchedulePair.second;
while (L && NumVisited == L->getNumBlocks()) {
auto *LDomain = isl_schedule_get_domain(LSchedulePair.first);
if (auto *MUPA = mapToDimension(LDomain, LD + 1))
LSchedulePair.first =
isl_schedule_insert_partial_schedule(LSchedulePair.first, MUPA);
auto *PL = L->getParentLoop();
assert(LoopSchedules.count(PL));
auto &PSchedulePair = LoopSchedules[PL];
PSchedulePair.first =
combineInSequence(PSchedulePair.first, LSchedulePair.first);
PSchedulePair.second += NumVisited;
L = PL;
NumVisited = PSchedulePair.second;
}
}
}
ScopStmt *Scop::getStmtForBasicBlock(BasicBlock *BB) const {
auto StmtMapIt = StmtMap.find(BB);
if (StmtMapIt == StmtMap.end())
return nullptr;
return StmtMapIt->second;
}
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 (OpIBB != OpBB) {
addScalarReadAccess(OpI, PHI, OpBB);
addScalarWriteAccess(OpI);
}
} else if (ModelReadOnlyScalars && !isa<Constant>(Op)) {
addScalarReadAccess(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 the users in the same BB (statement)
if (UseParent == ParentBB)
continue;
// Do not build scalar dependences inside a non-affine subregion.
if (NonAffineSubRegion && NonAffineSubRegion->contains(UseParent))
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.
addScalarReadAccess(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;
addScalarReadAccess(Op, Inst);
}
}
return AnyCrossStmtUse;
}
extern MapInsnToMemAcc InsnToMemAcc;
void ScopInfo::buildMemoryAccess(
Instruction *Inst, Loop *L, Region *R,
const ScopDetection::BoxedLoopsSetTy *BoxedLoops) {
unsigned Size;
Type *SizeType;
Value *Val;
enum MemoryAccess::AccessType Type;
if (LoadInst *Load = dyn_cast<LoadInst>(Inst)) {
SizeType = Load->getType();
Size = TD->getTypeStoreSize(SizeType);
Type = MemoryAccess::READ;
Val = Load;
} else {
StoreInst *Store = cast<StoreInst>(Inst);
SizeType = Store->getValueOperand()->getType();
Size = TD->getTypeStoreSize(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)
if (!isAffineExpr(R, Subscript, *SE)) {
AllAffineSubcripts = false;
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)));
addExplicitAccess(Inst, Type, BasePointer->getValue(), Size, true,
Subscripts, SizesSCEV, Val);
return;
}
}
}
auto AccItr = InsnToMemAcc.find(Inst);
if (PollyDelinearize && AccItr != InsnToMemAcc.end()) {
addExplicitAccess(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;
}
bool IsAffine = !isVariantInNonAffineLoop &&
isAffineExpr(R, AccessFunction, *SE, BasePointer->getValue());
// 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;
addExplicitAccess(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::buildAccessFunctions(Region &R, BasicBlock &BB,
Region *NonAffineSubRegion,
bool IsExitBlock) {
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);
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;
if (isa<LoadInst>(Inst) || isa<StoreInst>(Inst))
buildMemoryAccess(Inst, L, &R, BoxedLoops);
if (isIgnoredIntrinsic(Inst))
continue;
if (buildScalarDependences(Inst, &R, NonAffineSubRegion)) {
if (!isa<StoreInst>(Inst))
addScalarWriteAccess(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,
MemoryAccess::AccessOrigin Origin) {
AccFuncSetType &AccList = AccFuncMap[BB];
size_t Identifier = AccList.size();
Value *BaseAddr = BaseAddress;
std::string BaseName = getIslCompatibleName("MemRef_", BaseAddr, "");
std::string IdName = "__polly_array_ref_" + std::to_string(Identifier);
isl_id *Id = isl_id_alloc(ctx, IdName.c_str(), nullptr);
AccList.emplace_back(Inst, Id, Type, BaseAddress, ElemBytes, Affine,
Subscripts, Sizes, AccessValue, Origin, BaseName);
}
void ScopInfo::addExplicitAccess(
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,
MemoryAccess::EXPLICIT);
}
void ScopInfo::addScalarWriteAccess(Instruction *Value) {
addMemoryAccess(Value->getParent(), Value, MemoryAccess::MUST_WRITE, Value, 1,
true, Value, ArrayRef<const SCEV *>(),
ArrayRef<const SCEV *>(), MemoryAccess::SCALAR);
}
void ScopInfo::addScalarReadAccess(Value *Value, Instruction *User) {
assert(!isa<PHINode>(User));
addMemoryAccess(User->getParent(), User, MemoryAccess::READ, Value, 1, true,
Value, ArrayRef<const SCEV *>(), ArrayRef<const SCEV *>(),
MemoryAccess::SCALAR);
}
void ScopInfo::addScalarReadAccess(Value *Value, PHINode *User,
BasicBlock *UserBB) {
addMemoryAccess(UserBB, User, MemoryAccess::READ, Value, 1, true, Value,
ArrayRef<const SCEV *>(), ArrayRef<const SCEV *>(),
MemoryAccess::SCALAR);
}
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 ? MemoryAccess::SCALAR : MemoryAccess::PHI);
}
void ScopInfo::addPHIReadAccess(PHINode *PHI) {
addMemoryAccess(PHI->getParent(), PHI, MemoryAccess::READ, PHI, 1, true, PHI,
ArrayRef<const SCEV *>(), ArrayRef<const SCEV *>(),
MemoryAccess::PHI);
}
void ScopInfo::buildScop(Region &R, DominatorTree &DT) {
unsigned MaxLoopDepth = getMaxLoopDepthInRegion(R, *LI, *SD);
scop = new Scop(R, AccFuncMap, *SE, DT, ctx, MaxLoopDepth);
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(*LI, *SD, *AA);
}
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.addRequiredID(IndependentBlocksID);
AU.addRequired<LoopInfoWrapperPass>();
AU.addRequired<RegionInfoPass>();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequiredTransitive<ScalarEvolutionWrapperPass>();
AU.addRequiredTransitive<ScopDetection>();
AU.addRequired<AAResultsWrapperPass>();
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();
DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
buildScop(*R, DT);
DEBUG(scop->print(dbgs()));
if (!scop->hasFeasibleRuntimeContext()) {
delete scop;
scop = nullptr;
return false;
}
// Statistics.
++ScopFound;
if (scop->getMaxLoopDepth() > 0)
++RichScopFound;
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(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)