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

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//===--------- ScopInfo.cpp ----------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Create a polyhedral description for a static control flow region.
//
// The pass creates a polyhedral description of the Scops detected by the Scop
// detection derived from their LLVM-IR code.
//
// This representation is shared among several tools in the polyhedral
// community, which are e.g. Cloog, Pluto, Loopo, Graphite.
//
//===----------------------------------------------------------------------===//
#include "polly/ScopInfo.h"
#include "polly/LinkAllPasses.h"
#include "polly/Options.h"
#include "polly/ScopBuilder.h"
#include "polly/Support/GICHelper.h"
#include "polly/Support/SCEVValidator.h"
#include "polly/Support/ScopHelper.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopIterator.h"
#include "llvm/Analysis/RegionIterator.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/Support/Debug.h"
#include "isl/aff.h"
#include "isl/constraint.h"
#include "isl/local_space.h"
#include "isl/map.h"
#include "isl/options.h"
#include "isl/printer.h"
#include "isl/schedule.h"
#include "isl/schedule_node.h"
#include "isl/set.h"
#include "isl/union_map.h"
#include "isl/union_set.h"
#include "isl/val.h"
#include <sstream>
#include <string>
#include <vector>
using namespace llvm;
using namespace polly;
#define DEBUG_TYPE "polly-scops"
// The maximal number of basic sets we allow during domain construction to
// be created. More complex scops will result in very high compile time and
// are also unlikely to result in good code
static int const MaxDisjunctionsInDomain = 20;
static cl::opt<bool> PollyRemarksMinimal(
"polly-remarks-minimal",
cl::desc("Do not emit remarks about assumptions that are known"),
cl::Hidden, cl::ZeroOrMore, cl::init(false), cl::cat(PollyCategory));
// Multiplicative reductions can be disabled separately as these kind of
// operations can overflow easily. Additive reductions and bit operations
// are in contrast pretty stable.
static cl::opt<bool> DisableMultiplicativeReductions(
"polly-disable-multiplicative-reductions",
cl::desc("Disable multiplicative reductions"), cl::Hidden, cl::ZeroOrMore,
cl::init(false), cl::cat(PollyCategory));
static cl::opt<unsigned> RunTimeChecksMaxParameters(
"polly-rtc-max-parameters",
cl::desc("The maximal number of parameters allowed in RTCs."), cl::Hidden,
cl::ZeroOrMore, cl::init(8), cl::cat(PollyCategory));
static cl::opt<unsigned> RunTimeChecksMaxArraysPerGroup(
"polly-rtc-max-arrays-per-group",
cl::desc("The maximal number of arrays to compare in each alias group."),
cl::Hidden, cl::ZeroOrMore, cl::init(20), cl::cat(PollyCategory));
static cl::opt<std::string> UserContextStr(
"polly-context", cl::value_desc("isl parameter set"),
cl::desc("Provide additional constraints on the context parameters"),
cl::init(""), cl::cat(PollyCategory));
static cl::opt<bool> DetectReductions("polly-detect-reductions",
cl::desc("Detect and exploit reductions"),
cl::Hidden, cl::ZeroOrMore,
cl::init(true), cl::cat(PollyCategory));
static cl::opt<bool>
IslOnErrorAbort("polly-on-isl-error-abort",
cl::desc("Abort if an isl error is encountered"),
cl::init(true), cl::cat(PollyCategory));
//===----------------------------------------------------------------------===//
// Create a sequence of two schedules. Either argument may be null and is
// interpreted as the empty schedule. Can also return null if both schedules are
// empty.
static __isl_give isl_schedule *
combineInSequence(__isl_take isl_schedule *Prev,
__isl_take isl_schedule *Succ) {
if (!Prev)
return Succ;
if (!Succ)
return Prev;
return isl_schedule_sequence(Prev, Succ);
}
static __isl_give isl_set *addRangeBoundsToSet(__isl_take isl_set *S,
const ConstantRange &Range,
int dim,
enum isl_dim_type type) {
isl_val *V;
isl_ctx *ctx = isl_set_get_ctx(S);
bool useLowerUpperBound = Range.isSignWrappedSet() && !Range.isFullSet();
const auto LB = useLowerUpperBound ? Range.getLower() : Range.getSignedMin();
V = isl_valFromAPInt(ctx, LB, true);
isl_set *SLB = isl_set_lower_bound_val(isl_set_copy(S), type, dim, V);
const auto UB = useLowerUpperBound ? Range.getUpper() : Range.getSignedMax();
V = isl_valFromAPInt(ctx, UB, true);
if (useLowerUpperBound)
V = isl_val_sub_ui(V, 1);
isl_set *SUB = isl_set_upper_bound_val(S, type, dim, V);
if (useLowerUpperBound)
return isl_set_union(SLB, SUB);
else
return isl_set_intersect(SLB, SUB);
}
static const ScopArrayInfo *identifyBasePtrOriginSAI(Scop *S, Value *BasePtr) {
LoadInst *BasePtrLI = dyn_cast<LoadInst>(BasePtr);
if (!BasePtrLI)
return nullptr;
if (!S->contains(BasePtrLI))
return nullptr;
ScalarEvolution &SE = *S->getSE();
auto *OriginBaseSCEV =
SE.getPointerBase(SE.getSCEV(BasePtrLI->getPointerOperand()));
if (!OriginBaseSCEV)
return nullptr;
auto *OriginBaseSCEVUnknown = dyn_cast<SCEVUnknown>(OriginBaseSCEV);
if (!OriginBaseSCEVUnknown)
return nullptr;
return S->getScopArrayInfo(OriginBaseSCEVUnknown->getValue(),
ScopArrayInfo::MK_Array);
}
ScopArrayInfo::ScopArrayInfo(Value *BasePtr, Type *ElementType, isl_ctx *Ctx,
ArrayRef<const SCEV *> Sizes, enum MemoryKind Kind,
const DataLayout &DL, Scop *S)
: BasePtr(BasePtr), ElementType(ElementType), Kind(Kind), DL(DL), S(*S) {
std::string BasePtrName =
getIslCompatibleName("MemRef_", BasePtr, Kind == MK_PHI ? "__phi" : "");
Id = isl_id_alloc(Ctx, BasePtrName.c_str(), this);
updateSizes(Sizes);
BasePtrOriginSAI = identifyBasePtrOriginSAI(S, BasePtr);
if (BasePtrOriginSAI)
const_cast<ScopArrayInfo *>(BasePtrOriginSAI)->addDerivedSAI(this);
}
__isl_give isl_space *ScopArrayInfo::getSpace() const {
auto *Space =
isl_space_set_alloc(isl_id_get_ctx(Id), 0, getNumberOfDimensions());
Space = isl_space_set_tuple_id(Space, isl_dim_set, isl_id_copy(Id));
return Space;
}
void ScopArrayInfo::updateElementType(Type *NewElementType) {
if (NewElementType == ElementType)
return;
auto OldElementSize = DL.getTypeAllocSizeInBits(ElementType);
auto NewElementSize = DL.getTypeAllocSizeInBits(NewElementType);
if (NewElementSize == OldElementSize || NewElementSize == 0)
return;
if (NewElementSize % OldElementSize == 0 && NewElementSize < OldElementSize) {
ElementType = NewElementType;
} else {
auto GCD = GreatestCommonDivisor64(NewElementSize, OldElementSize);
ElementType = IntegerType::get(ElementType->getContext(), GCD);
}
}
bool ScopArrayInfo::updateSizes(ArrayRef<const SCEV *> NewSizes) {
int SharedDims = std::min(NewSizes.size(), DimensionSizes.size());
int ExtraDimsNew = NewSizes.size() - SharedDims;
int ExtraDimsOld = DimensionSizes.size() - SharedDims;
for (int i = 0; i < SharedDims; i++)
if (NewSizes[i + ExtraDimsNew] != DimensionSizes[i + ExtraDimsOld])
return false;
if (DimensionSizes.size() >= NewSizes.size())
return true;
DimensionSizes.clear();
DimensionSizes.insert(DimensionSizes.begin(), NewSizes.begin(),
NewSizes.end());
for (isl_pw_aff *Size : DimensionSizesPw)
isl_pw_aff_free(Size);
DimensionSizesPw.clear();
for (const SCEV *Expr : DimensionSizes) {
isl_pw_aff *Size = S.getPwAffOnly(Expr);
DimensionSizesPw.push_back(Size);
}
return true;
}
ScopArrayInfo::~ScopArrayInfo() {
isl_id_free(Id);
for (isl_pw_aff *Size : DimensionSizesPw)
isl_pw_aff_free(Size);
}
std::string ScopArrayInfo::getName() const { return isl_id_get_name(Id); }
int ScopArrayInfo::getElemSizeInBytes() const {
return DL.getTypeAllocSize(ElementType);
}
__isl_give isl_id *ScopArrayInfo::getBasePtrId() const {
return isl_id_copy(Id);
}
void ScopArrayInfo::dump() const { print(errs()); }
void ScopArrayInfo::print(raw_ostream &OS, bool SizeAsPwAff) const {
OS.indent(8) << *getElementType() << " " << getName();
if (getNumberOfDimensions() > 0)
OS << "[*]";
for (unsigned u = 1; u < getNumberOfDimensions(); u++) {
OS << "[";
if (SizeAsPwAff) {
auto *Size = getDimensionSizePw(u);
OS << " " << Size << " ";
isl_pw_aff_free(Size);
} else {
OS << *getDimensionSize(u);
}
OS << "]";
}
OS << ";";
if (BasePtrOriginSAI)
OS << " [BasePtrOrigin: " << BasePtrOriginSAI->getName() << "]";
OS << " // Element size " << getElemSizeInBytes() << "\n";
}
const ScopArrayInfo *
ScopArrayInfo::getFromAccessFunction(__isl_keep isl_pw_multi_aff *PMA) {
isl_id *Id = isl_pw_multi_aff_get_tuple_id(PMA, isl_dim_out);
assert(Id && "Output dimension didn't have an ID");
return getFromId(Id);
}
const ScopArrayInfo *ScopArrayInfo::getFromId(isl_id *Id) {
void *User = isl_id_get_user(Id);
const ScopArrayInfo *SAI = static_cast<ScopArrayInfo *>(User);
isl_id_free(Id);
return SAI;
}
void MemoryAccess::wrapConstantDimensions() {
auto *SAI = getScopArrayInfo();
auto *ArraySpace = SAI->getSpace();
auto *Ctx = isl_space_get_ctx(ArraySpace);
unsigned DimsArray = SAI->getNumberOfDimensions();
auto *DivModAff = isl_multi_aff_identity(isl_space_map_from_domain_and_range(
isl_space_copy(ArraySpace), isl_space_copy(ArraySpace)));
auto *LArraySpace = isl_local_space_from_space(ArraySpace);
// Begin with last dimension, to iteratively carry into higher dimensions.
for (int i = DimsArray - 1; i > 0; i--) {
auto *DimSize = SAI->getDimensionSize(i);
auto *DimSizeCst = dyn_cast<SCEVConstant>(DimSize);
// This transformation is not applicable to dimensions with dynamic size.
if (!DimSizeCst)
continue;
auto *DimSizeVal = isl_valFromAPInt(Ctx, DimSizeCst->getAPInt(), false);
auto *Var = isl_aff_var_on_domain(isl_local_space_copy(LArraySpace),
isl_dim_set, i);
auto *PrevVar = isl_aff_var_on_domain(isl_local_space_copy(LArraySpace),
isl_dim_set, i - 1);
// Compute: index % size
// Modulo must apply in the divide of the previous iteration, if any.
auto *Modulo = isl_aff_copy(Var);
Modulo = isl_aff_mod_val(Modulo, isl_val_copy(DimSizeVal));
Modulo = isl_aff_pullback_multi_aff(Modulo, isl_multi_aff_copy(DivModAff));
// Compute: floor(index / size)
auto *Divide = Var;
Divide = isl_aff_div(
Divide,
isl_aff_val_on_domain(isl_local_space_copy(LArraySpace), DimSizeVal));
Divide = isl_aff_floor(Divide);
Divide = isl_aff_add(Divide, PrevVar);
Divide = isl_aff_pullback_multi_aff(Divide, isl_multi_aff_copy(DivModAff));
// Apply Modulo and Divide.
DivModAff = isl_multi_aff_set_aff(DivModAff, i, Modulo);
DivModAff = isl_multi_aff_set_aff(DivModAff, i - 1, Divide);
}
// Apply all modulo/divides on the accesses.
AccessRelation =
isl_map_apply_range(AccessRelation, isl_map_from_multi_aff(DivModAff));
AccessRelation = isl_map_detect_equalities(AccessRelation);
isl_local_space_free(LArraySpace);
}
void MemoryAccess::updateDimensionality() {
auto *SAI = getScopArrayInfo();
auto *ArraySpace = SAI->getSpace();
auto *AccessSpace = isl_space_range(isl_map_get_space(AccessRelation));
auto *Ctx = isl_space_get_ctx(AccessSpace);
auto DimsArray = isl_space_dim(ArraySpace, isl_dim_set);
auto DimsAccess = isl_space_dim(AccessSpace, isl_dim_set);
auto DimsMissing = DimsArray - DimsAccess;
auto *BB = getStatement()->getEntryBlock();
auto &DL = BB->getModule()->getDataLayout();
unsigned ArrayElemSize = SAI->getElemSizeInBytes();
unsigned ElemBytes = DL.getTypeAllocSize(getElementType());
auto *Map = isl_map_from_domain_and_range(
isl_set_universe(AccessSpace),
isl_set_universe(isl_space_copy(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);
// 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. If the base pointer was accessed with offsets not divisible
// by the accesses element size, we will have choosen a smaller ArrayElemSize
// that divides the offsets of all accesses to this base pointer.
if (DimsAccess == 1) {
isl_val *V = isl_val_int_from_si(Ctx, ArrayElemSize);
AccessRelation = isl_map_floordiv_val(AccessRelation, V);
}
// We currently do this only if we added at least one dimension, which means
// some dimension's indices have not been specified, an indicator that some
// index values have been added together.
// TODO: Investigate general usefulness; Effect on unit tests is to make index
// expressions more complicated.
if (DimsMissing)
wrapConstantDimensions();
if (!isAffine())
computeBoundsOnAccessRelation(ArrayElemSize);
// Introduce multi-element accesses in case the type loaded by this memory
// access is larger than the canonical element type of the array.
//
// An access ((float *)A)[i] to an array char *A is modeled as
// {[i] -> A[o] : 4 i <= o <= 4 i + 3
if (ElemBytes > ArrayElemSize) {
assert(ElemBytes % ArrayElemSize == 0 &&
"Loaded element size should be multiple of canonical element size");
auto *Map = isl_map_from_domain_and_range(
isl_set_universe(isl_space_copy(ArraySpace)),
isl_set_universe(isl_space_copy(ArraySpace)));
for (unsigned i = 0; i < DimsArray - 1; i++)
Map = isl_map_equate(Map, isl_dim_in, i, isl_dim_out, i);
isl_constraint *C;
isl_local_space *LS;
LS = isl_local_space_from_space(isl_map_get_space(Map));
int Num = ElemBytes / getScopArrayInfo()->getElemSizeInBytes();
C = isl_constraint_alloc_inequality(isl_local_space_copy(LS));
C = isl_constraint_set_constant_val(C, isl_val_int_from_si(Ctx, Num - 1));
C = isl_constraint_set_coefficient_si(C, isl_dim_in, DimsArray - 1, 1);
C = isl_constraint_set_coefficient_si(C, isl_dim_out, DimsArray - 1, -1);
Map = isl_map_add_constraint(Map, C);
C = isl_constraint_alloc_inequality(LS);
C = isl_constraint_set_coefficient_si(C, isl_dim_in, DimsArray - 1, -1);
C = isl_constraint_set_coefficient_si(C, isl_dim_out, DimsArray - 1, 1);
C = isl_constraint_set_constant_val(C, isl_val_int_from_si(Ctx, 0));
Map = isl_map_add_constraint(Map, C);
AccessRelation = isl_map_apply_range(AccessRelation, Map);
}
isl_space_free(ArraySpace);
assumeNoOutOfBound();
}
const std::string
MemoryAccess::getReductionOperatorStr(MemoryAccess::ReductionType RT) {
switch (RT) {
case MemoryAccess::RT_NONE:
llvm_unreachable("Requested a reduction operator string for a memory "
"access which isn't a reduction");
case MemoryAccess::RT_ADD:
return "+";
case MemoryAccess::RT_MUL:
return "*";
case MemoryAccess::RT_BOR:
return "|";
case MemoryAccess::RT_BXOR:
return "^";
case MemoryAccess::RT_BAND:
return "&";
}
llvm_unreachable("Unknown reduction type");
return "";
}
/// @brief Return the reduction type for a given binary operator
static MemoryAccess::ReductionType getReductionType(const BinaryOperator *BinOp,
const Instruction *Load) {
if (!BinOp)
return MemoryAccess::RT_NONE;
switch (BinOp->getOpcode()) {
case Instruction::FAdd:
if (!BinOp->hasUnsafeAlgebra())
return MemoryAccess::RT_NONE;
// Fall through
case Instruction::Add:
return MemoryAccess::RT_ADD;
case Instruction::Or:
return MemoryAccess::RT_BOR;
case Instruction::Xor:
return MemoryAccess::RT_BXOR;
case Instruction::And:
return MemoryAccess::RT_BAND;
case Instruction::FMul:
if (!BinOp->hasUnsafeAlgebra())
return MemoryAccess::RT_NONE;
// Fall through
case Instruction::Mul:
if (DisableMultiplicativeReductions)
return MemoryAccess::RT_NONE;
return MemoryAccess::RT_MUL;
default:
return MemoryAccess::RT_NONE;
}
}
MemoryAccess::~MemoryAccess() {
isl_id_free(Id);
isl_set_free(InvalidDomain);
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_map *MemoryAccess::getAddressFunction() const {
return isl_map_lexmin(getAccessRelation());
}
__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(getAddressFunction(), 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() {
auto *SAI = getScopArrayInfo();
isl_space *Space = isl_space_range(getOriginalAccessRelationSpace());
isl_set *Outside = isl_set_empty(isl_space_copy(Space));
for (int i = 1, Size = isl_space_dim(Space, isl_dim_set); i < Size; ++i) {
isl_local_space *LS = isl_local_space_from_space(isl_space_copy(Space));
isl_pw_aff *Var =
isl_pw_aff_var_on_domain(isl_local_space_copy(LS), isl_dim_set, i);
isl_pw_aff *Zero = isl_pw_aff_zero_on_domain(LS);
isl_set *DimOutside;
DimOutside = isl_pw_aff_lt_set(isl_pw_aff_copy(Var), Zero);
isl_pw_aff *SizeE = SAI->getDimensionSizePw(i);
SizeE = isl_pw_aff_add_dims(SizeE, isl_dim_in,
isl_space_dim(Space, isl_dim_set));
SizeE = isl_pw_aff_set_tuple_id(SizeE, isl_dim_in,
isl_space_get_tuple_id(Space, isl_dim_set));
DimOutside = isl_set_union(DimOutside, isl_pw_aff_le_set(SizeE, Var));
Outside = isl_set_union(Outside, DimOutside);
}
Outside = isl_set_apply(Outside, isl_map_reverse(getAccessRelation()));
Outside = isl_set_intersect(Outside, Statement->getDomain());
Outside = isl_set_params(Outside);
// Remove divs to avoid the construction of overly complicated assumptions.
// Doing so increases the set of parameter combinations that are assumed to
// not appear. This is always save, but may make the resulting run-time check
// bail out more often than strictly necessary.
Outside = isl_set_remove_divs(Outside);
Outside = isl_set_complement(Outside);
const auto &Loc = getAccessInstruction()
? getAccessInstruction()->getDebugLoc()
: DebugLoc();
Statement->getParent()->recordAssumption(INBOUNDS, Outside, Loc,
AS_ASSUMPTION);
isl_space_free(Space);
}
void MemoryAccess::buildMemIntrinsicAccessRelation() {
assert(isa<MemIntrinsic>(getAccessInstruction()));
assert(Subscripts.size() == 2 && Sizes.size() == 0);
auto *SubscriptPWA = getPwAff(Subscripts[0]);
auto *SubscriptMap = isl_map_from_pw_aff(SubscriptPWA);
isl_map *LengthMap;
if (Subscripts[1] == nullptr) {
LengthMap = isl_map_universe(isl_map_get_space(SubscriptMap));
} else {
auto *LengthPWA = getPwAff(Subscripts[1]);
LengthMap = isl_map_from_pw_aff(LengthPWA);
auto *RangeSpace = isl_space_range(isl_map_get_space(LengthMap));
LengthMap = isl_map_apply_range(LengthMap, isl_map_lex_gt(RangeSpace));
}
LengthMap = isl_map_lower_bound_si(LengthMap, isl_dim_out, 0, 0);
LengthMap = isl_map_align_params(LengthMap, isl_map_get_space(SubscriptMap));
SubscriptMap =
isl_map_align_params(SubscriptMap, isl_map_get_space(LengthMap));
LengthMap = isl_map_sum(LengthMap, SubscriptMap);
AccessRelation = isl_map_set_tuple_id(LengthMap, isl_dim_in,
getStatement()->getDomainId());
}
void MemoryAccess::computeBoundsOnAccessRelation(unsigned ElementSize) {
ScalarEvolution *SE = Statement->getParent()->getSE();
auto MAI = MemAccInst(getAccessInstruction());
if (isa<MemIntrinsic>(MAI))
return;
Value *Ptr = MAI.getPointerOperand();
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 One = APInt(BW, 1);
const auto LB = isWrapping ? Range.getLower() : Range.getSignedMin();
const auto UB = isWrapping ? (Range.getUpper() - One) : Range.getSignedMax();
auto Min = LB.sdiv(APInt(BW, ElementSize));
auto Max = UB.sdiv(APInt(BW, ElementSize)) + One;
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 = getPwAff(Sizes[i]);
isl_space *SpaceSize = isl_pw_aff_get_space(DimSize);
isl_pw_aff_free(DimSize);
isl_id *ParamId = isl_space_get_dim_id(SpaceSize, isl_dim_param, 0);
Space = isl_map_get_space(AccessRelation);
Space = isl_space_map_from_set(isl_space_range(Space));
Space = isl_space_align_params(Space, SpaceSize);
int ParamLocation = isl_space_find_dim_by_id(Space, isl_dim_param, ParamId);
isl_id_free(ParamId);
MapOne = isl_map_universe(isl_space_copy(Space));
for (int j = 0; j < Size; ++j)
MapOne = isl_map_equate(MapOne, isl_dim_in, j, isl_dim_out, j);
MapOne = isl_map_lower_bound_si(MapOne, isl_dim_in, i + 1, 0);
MapTwo = isl_map_universe(isl_space_copy(Space));
for (int j = 0; j < Size; ++j)
if (j < i || j > i + 1)
MapTwo = isl_map_equate(MapTwo, isl_dim_in, j, isl_dim_out, j);
isl_local_space *LS = isl_local_space_from_space(Space);
isl_constraint *C;
C = isl_equality_alloc(isl_local_space_copy(LS));
C = isl_constraint_set_constant_si(C, -1);
C = isl_constraint_set_coefficient_si(C, isl_dim_in, i, 1);
C = isl_constraint_set_coefficient_si(C, isl_dim_out, i, -1);
MapTwo = isl_map_add_constraint(MapTwo, C);
C = isl_equality_alloc(LS);
C = isl_constraint_set_coefficient_si(C, isl_dim_in, i + 1, 1);
C = isl_constraint_set_coefficient_si(C, isl_dim_out, i + 1, -1);
C = isl_constraint_set_coefficient_si(C, isl_dim_param, ParamLocation, 1);
MapTwo = isl_map_add_constraint(MapTwo, C);
MapTwo = isl_map_upper_bound_si(MapTwo, isl_dim_in, i + 1, -1);
MapOne = isl_map_union(MapOne, MapTwo);
AccessRelation = isl_map_apply_range(AccessRelation, MapOne);
}
return AccessRelation;
}
/// @brief Check if @p Expr is divisible by @p Size.
static bool isDivisible(const SCEV *Expr, unsigned Size, ScalarEvolution &SE) {
assert(Size != 0);
if (Size == 1)
return true;
// Only one factor needs to be divisible.
if (auto *MulExpr = dyn_cast<SCEVMulExpr>(Expr)) {
for (auto *FactorExpr : MulExpr->operands())
if (isDivisible(FactorExpr, Size, SE))
return true;
return false;
}
// For other n-ary expressions (Add, AddRec, Max,...) all operands need
// to be divisble.
if (auto *NAryExpr = dyn_cast<SCEVNAryExpr>(Expr)) {
for (auto *OpExpr : NAryExpr->operands())
if (!isDivisible(OpExpr, Size, SE))
return false;
return true;
}
auto *SizeSCEV = SE.getConstant(Expr->getType(), Size);
auto *UDivSCEV = SE.getUDivExpr(Expr, SizeSCEV);
auto *MulSCEV = SE.getMulExpr(UDivSCEV, SizeSCEV);
return MulSCEV == Expr;
}
void MemoryAccess::buildAccessRelation(const ScopArrayInfo *SAI) {
assert(!AccessRelation && "AccessReltation already built");
// Initialize the invalid domain which describes all iterations for which the
// access relation is not modeled correctly.
auto *StmtInvalidDomain = getStatement()->getInvalidDomain();
InvalidDomain = isl_set_empty(isl_set_get_space(StmtInvalidDomain));
isl_set_free(StmtInvalidDomain);
isl_ctx *Ctx = isl_id_get_ctx(Id);
isl_id *BaseAddrId = SAI->getBasePtrId();
if (!isAffine()) {
if (isa<MemIntrinsic>(getAccessInstruction()))
buildMemIntrinsicAccessRelation();
// 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.
if (!AccessRelation)
AccessRelation = isl_map_from_basic_map(createBasicAccessMap(Statement));
AccessRelation =
isl_map_set_tuple_id(AccessRelation, isl_dim_out, BaseAddrId);
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 = getPwAff(Subscripts[i]);
isl_map *SubscriptMap = isl_map_from_pw_aff(Affine);
AccessRelation = isl_map_flat_range_product(AccessRelation, SubscriptMap);
}
if (Sizes.size() >= 1 && !isa<SCEVConstant>(Sizes[0]))
AccessRelation = foldAccess(AccessRelation, Statement);
Space = Statement->getDomainSpace();
AccessRelation = isl_map_set_tuple_id(
AccessRelation, isl_dim_in, isl_space_get_tuple_id(Space, isl_dim_set));
AccessRelation =
isl_map_set_tuple_id(AccessRelation, isl_dim_out, BaseAddrId);
AccessRelation = isl_map_gist_domain(AccessRelation, Statement->getDomain());
isl_space_free(Space);
}
MemoryAccess::MemoryAccess(ScopStmt *Stmt, Instruction *AccessInst,
AccessType AccType, Value *BaseAddress,
Type *ElementType, bool Affine,
ArrayRef<const SCEV *> Subscripts,
ArrayRef<const SCEV *> Sizes, Value *AccessValue,
ScopArrayInfo::MemoryKind Kind, StringRef BaseName)
: Kind(Kind), AccType(AccType), RedType(RT_NONE), Statement(Stmt),
InvalidDomain(nullptr), BaseAddr(BaseAddress), BaseName(BaseName),
ElementType(ElementType), Sizes(Sizes.begin(), Sizes.end()),
AccessInstruction(AccessInst), AccessValue(AccessValue), IsAffine(Affine),
Subscripts(Subscripts.begin(), Subscripts.end()), AccessRelation(nullptr),
NewAccessRelation(nullptr) {
static const std::string TypeStrings[] = {"", "_Read", "_Write", "_MayWrite"};
const std::string Access = TypeStrings[AccType] + utostr(Stmt->size()) + "_";
std::string IdName =
getIslCompatibleName(Stmt->getBaseName(), Access, BaseName);
Id = isl_id_alloc(Stmt->getParent()->getIslCtx(), IdName.c_str(), this);
}
void MemoryAccess::realignParams() {
auto *Ctx = Statement->getParent()->getContext();
InvalidDomain = isl_set_gist_params(InvalidDomain, isl_set_copy(Ctx));
AccessRelation = isl_map_gist_params(AccessRelation, Ctx);
}
const std::string MemoryAccess::getReductionOperatorStr() const {
return MemoryAccess::getReductionOperatorStr(getReductionType());
}
__isl_give isl_id *MemoryAccess::getId() const { return isl_id_copy(Id); }
raw_ostream &polly::operator<<(raw_ostream &OS,
MemoryAccess::ReductionType RT) {
if (RT == MemoryAccess::RT_NONE)
OS << "NONE";
else
OS << MemoryAccess::getReductionOperatorStr(RT);
return OS;
}
void MemoryAccess::print(raw_ostream &OS) const {
switch (AccType) {
case READ:
OS.indent(12) << "ReadAccess :=\t";
break;
case MUST_WRITE:
OS.indent(12) << "MustWriteAccess :=\t";
break;
case MAY_WRITE:
OS.indent(12) << "MayWriteAccess :=\t";
break;
}
OS << "[Reduction Type: " << getReductionType() << "] ";
OS << "[Scalar: " << isScalarKind() << "]\n";
OS.indent(16) << getOriginalAccessRelationStr() << ";\n";
if (hasNewAccessRelation())
OS.indent(11) << "new: " << getNewAccessRelationStr() << ";\n";
}
void MemoryAccess::dump() const { print(errs()); }
__isl_give isl_pw_aff *MemoryAccess::getPwAff(const SCEV *E) {
auto *Stmt = getStatement();
PWACtx PWAC = Stmt->getParent()->getPwAff(E, Stmt->getEntryBlock());
isl_set *StmtDom = isl_set_reset_tuple_id(getStatement()->getDomain());
isl_set *NewInvalidDom = isl_set_intersect(StmtDom, PWAC.second);
InvalidDomain = isl_set_union(InvalidDomain, NewInvalidDom);
return PWAC.first;
}
// 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_give 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, bool NonNegative) {
PWACtx PWAC = getParent()->getPwAff(E, getEntryBlock(), NonNegative);
InvalidDomain = isl_set_union(InvalidDomain, PWAC.second);
return PWAC.first;
}
void ScopStmt::restrictDomain(__isl_take isl_set *NewDomain) {
assert(isl_set_is_subset(NewDomain, Domain) &&
"New domain is not a subset of old domain!");
isl_set_free(Domain);
Domain = NewDomain;
}
void ScopStmt::buildAccessRelations() {
Scop &S = *getParent();
for (MemoryAccess *Access : MemAccs) {
Type *ElementType = Access->getElementType();
ScopArrayInfo::MemoryKind Ty;
if (Access->isPHIKind())
Ty = ScopArrayInfo::MK_PHI;
else if (Access->isExitPHIKind())
Ty = ScopArrayInfo::MK_ExitPHI;
else if (Access->isValueKind())
Ty = ScopArrayInfo::MK_Value;
else
Ty = ScopArrayInfo::MK_Array;
auto *SAI = S.getOrCreateScopArrayInfo(Access->getBaseAddr(), ElementType,
Access->Sizes, Ty);
Access->buildAccessRelation(SAI);
}
}
void ScopStmt::addAccess(MemoryAccess *Access) {
Instruction *AccessInst = Access->getAccessInstruction();
if (Access->isArrayKind()) {
MemoryAccessList &MAL = InstructionToAccess[AccessInst];
MAL.emplace_front(Access);
} else if (Access->isValueKind() && Access->isWrite()) {
Instruction *AccessVal = cast<Instruction>(Access->getAccessValue());
assert(Parent.getStmtFor(AccessVal) == this);
assert(!ValueWrites.lookup(AccessVal));
ValueWrites[AccessVal] = Access;
} else if (Access->isValueKind() && Access->isRead()) {
Value *AccessVal = Access->getAccessValue();
assert(!ValueReads.lookup(AccessVal));
ValueReads[AccessVal] = Access;
} else if (Access->isAnyPHIKind() && Access->isWrite()) {
PHINode *PHI = cast<PHINode>(Access->getBaseAddr());
assert(!PHIWrites.lookup(PHI));
PHIWrites[PHI] = Access;
}
MemAccs.push_back(Access);
}
void ScopStmt::realignParams() {
for (MemoryAccess *MA : *this)
MA->realignParams();
auto *Ctx = Parent.getContext();
InvalidDomain = isl_set_gist_params(InvalidDomain, isl_set_copy(Ctx));
Domain = isl_set_gist_params(Domain, Ctx);
}
/// @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 bool
buildConditionSets(ScopStmt &Stmt, 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");
Scop &S = *Stmt.getParent();
ScalarEvolution &SE = *S.getSE();
isl_pw_aff *LHS, *RHS;
LHS = Stmt.getPwAff(SE.getSCEVAtScope(Condition, L));
unsigned NumSuccessors = SI->getNumSuccessors();
ConditionSets.resize(NumSuccessors);
for (auto &Case : SI->cases()) {
unsigned Idx = Case.getSuccessorIndex();
ConstantInt *CaseValue = Case.getCaseValue();
RHS = Stmt.getPwAff(SE.getSCEV(CaseValue));
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));
isl_pw_aff_free(LHS);
return true;
}
/// @brief Build the conditions sets for the branch condition @p Condition in
/// the @p Domain.
///
/// This will fill @p ConditionSets with the conditions under which control
/// will be moved from @p TI to its successors. Hence, @p ConditionSets will
/// have as many elements as @p TI has successors. If @p TI is nullptr the
/// context under which @p Condition is true/false will be returned as the
/// new elements of @p ConditionSets.
static bool
buildConditionSets(ScopStmt &Stmt, Value *Condition, TerminatorInst *TI,
Loop *L, __isl_keep isl_set *Domain,
SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
Scop &S = *Stmt.getParent();
isl_set *ConsequenceCondSet = nullptr;
if (auto *CCond = dyn_cast<ConstantInt>(Condition)) {
if (CCond->isZero())
ConsequenceCondSet = isl_set_empty(isl_set_get_space(Domain));
else
ConsequenceCondSet = isl_set_universe(isl_set_get_space(Domain));
} else if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Condition)) {
auto Opcode = BinOp->getOpcode();
assert(Opcode == Instruction::And || Opcode == Instruction::Or);
bool Valid = buildConditionSets(Stmt, BinOp->getOperand(0), TI, L, Domain,
ConditionSets) &&
buildConditionSets(Stmt, BinOp->getOperand(1), TI, L, Domain,
ConditionSets);
if (!Valid) {
while (!ConditionSets.empty())
isl_set_free(ConditionSets.pop_back_val());
return false;
}
isl_set_free(ConditionSets.pop_back_val());
isl_set *ConsCondPart0 = ConditionSets.pop_back_val();
isl_set_free(ConditionSets.pop_back_val());
isl_set *ConsCondPart1 = ConditionSets.pop_back_val();
if (Opcode == Instruction::And)
ConsequenceCondSet = isl_set_intersect(ConsCondPart0, ConsCondPart1);
else
ConsequenceCondSet = isl_set_union(ConsCondPart0, ConsCondPart1);
} else {
auto *ICond = dyn_cast<ICmpInst>(Condition);
assert(ICond &&
"Condition of exiting branch was neither constant nor ICmp!");
ScalarEvolution &SE = *S.getSE();
isl_pw_aff *LHS, *RHS;
// For unsigned comparisons we assumed the signed bit of neither operand
// to be set. The comparison is equal to a signed comparison under this
// assumption.
bool NonNeg = ICond->isUnsigned();
LHS = Stmt.getPwAff(SE.getSCEVAtScope(ICond->getOperand(0), L), NonNeg);
RHS = Stmt.getPwAff(SE.getSCEVAtScope(ICond->getOperand(1), L), NonNeg);
ConsequenceCondSet =
buildConditionSet(ICond->getPredicate(), LHS, RHS, Domain);
}
// If no terminator was given we are only looking for parameter constraints
// under which @p Condition is true/false.
if (!TI)
ConsequenceCondSet = isl_set_params(ConsequenceCondSet);
assert(ConsequenceCondSet);
ConsequenceCondSet = isl_set_coalesce(
isl_set_intersect(ConsequenceCondSet, isl_set_copy(Domain)));
isl_set *AlternativeCondSet = nullptr;
bool TooComplex =
isl_set_n_basic_set(ConsequenceCondSet) >= MaxDisjunctionsInDomain;
if (!TooComplex) {
AlternativeCondSet = isl_set_subtract(isl_set_copy(Domain),
isl_set_copy(ConsequenceCondSet));
TooComplex =
isl_set_n_basic_set(AlternativeCondSet) >= MaxDisjunctionsInDomain;
}
if (TooComplex) {
S.invalidate(COMPLEXITY, TI ? TI->getDebugLoc() : DebugLoc());
isl_set_free(AlternativeCondSet);
isl_set_free(ConsequenceCondSet);
return false;
}
ConditionSets.push_back(ConsequenceCondSet);
ConditionSets.push_back(isl_set_coalesce(AlternativeCondSet));
return true;
}
/// @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 bool
buildConditionSets(ScopStmt &Stmt, TerminatorInst *TI, Loop *L,
__isl_keep isl_set *Domain,
SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
if (SwitchInst *SI = dyn_cast<SwitchInst>(TI))
return buildConditionSets(Stmt, 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 true;
}
Value *Condition = getConditionFromTerminator(TI);
assert(Condition && "No condition for Terminator");
return buildConditionSets(Stmt, Condition, TI, L, Domain, ConditionSets);
}
void ScopStmt::buildDomain() {
isl_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, LoopInfo &LI) {
isl_ctx *Ctx = Parent.getIslCtx();
isl_local_space *LSpace = isl_local_space_from_space(getDomainSpace());
ScalarEvolution &SE = *Parent.getSE();
// The set of loads that are required to be invariant.
auto &ScopRIL = Parent.getRequiredInvariantLoads();
std::vector<const SCEV *> Subscripts;
std::vector<int> Sizes;
std::tie(Subscripts, Sizes) = getIndexExpressionsFromGEP(GEP, SE);
int IndexOffset = Subscripts.size() - Sizes.size();
assert(IndexOffset <= 1 && "Unexpected large index offset");
auto *NotExecuted = isl_set_complement(isl_set_params(getDomain()));
for (size_t i = 0; i < Sizes.size(); i++) {
auto *Expr = Subscripts[i + IndexOffset];
auto Size = Sizes[i];
auto *Scope = LI.getLoopFor(getEntryBlock());
InvariantLoadsSetTy AccessILS;
if (!isAffineExpr(&Parent.getRegion(), Scope, Expr, SE, &AccessILS))
continue;
bool NonAffine = false;
for (LoadInst *LInst : AccessILS)
if (!ScopRIL.count(LInst))
NonAffine = true;
if (NonAffine)
continue;
isl_pw_aff *AccessOffset = getPwAff(Expr);
AccessOffset =
isl_pw_aff_set_tuple_id(AccessOffset, isl_dim_in, getDomainId());
isl_pw_aff *DimSize = isl_pw_aff_from_aff(isl_aff_val_on_domain(
isl_local_space_copy(LSpace), isl_val_int_from_si(Ctx, Size)));
isl_set *OutOfBound = isl_pw_aff_ge_set(AccessOffset, DimSize);
OutOfBound = isl_set_intersect(getDomain(), OutOfBound);
OutOfBound = isl_set_params(OutOfBound);
isl_set *InBound = isl_set_complement(OutOfBound);
// A => B == !A or B
isl_set *InBoundIfExecuted =
isl_set_union(isl_set_copy(NotExecuted), InBound);
InBoundIfExecuted = isl_set_coalesce(InBoundIfExecuted);
Parent.recordAssumption(INBOUNDS, InBoundIfExecuted, GEP->getDebugLoc(),
AS_ASSUMPTION);
}
isl_local_space_free(LSpace);
isl_set_free(NotExecuted);
}
void ScopStmt::deriveAssumptions(LoopInfo &LI) {
for (auto *MA : *this) {
if (!MA->isArrayKind())
continue;
MemAccInst Acc(MA->getAccessInstruction());
auto *GEP = dyn_cast_or_null<GetElementPtrInst>(Acc.getPointerOperand());
if (GEP)
deriveAssumptionsFromGEP(GEP, LI);
}
}
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), InvalidDomain(nullptr), Domain(nullptr), BB(nullptr),
R(&R), Build(nullptr) {
BaseName = getIslCompatibleName("Stmt_", R.getNameStr(), "");
}
ScopStmt::ScopStmt(Scop &parent, BasicBlock &bb)
: Parent(parent), InvalidDomain(nullptr), Domain(nullptr), BB(&bb),
R(nullptr), Build(nullptr) {
BaseName = getIslCompatibleName("Stmt_", &bb, "");
}
void ScopStmt::init(LoopInfo &LI) {
assert(!Domain && "init must be called only once");
buildDomain();
collectSurroundingLoops();
buildAccessRelations();
deriveAssumptions(LI);
if (DetectReductions)
checkForReductions();
}
/// @brief Collect loads which might form a reduction chain with @p StoreMA
///
/// Check if the stored value for @p StoreMA is a binary operator with one or
/// two loads as operands. If the binary operand is commutative & associative,
/// used only once (by @p StoreMA) and its load operands are also used only
/// once, we have found a possible reduction chain. It starts at an operand
/// load and includes the binary operator and @p StoreMA.
///
/// Note: We allow only one use to ensure the load and binary operator cannot
/// escape this block or into any other store except @p StoreMA.
void ScopStmt::collectCandiateReductionLoads(
MemoryAccess *StoreMA, SmallVectorImpl<MemoryAccess *> &Loads) {
auto *Store = dyn_cast<StoreInst>(StoreMA->getAccessInstruction());
if (!Store)
return;
// Skip if there is not one binary operator between the load and the store
auto *BinOp = dyn_cast<BinaryOperator>(Store->getValueOperand());
if (!BinOp)
return;
// Skip if the binary operators has multiple uses
if (BinOp->getNumUses() != 1)
return;
// Skip if the opcode of the binary operator is not commutative/associative
if (!BinOp->isCommutative() || !BinOp->isAssociative())
return;
// Skip if the binary operator is outside the current SCoP
if (BinOp->getParent() != Store->getParent())
return;
// Skip if it is a multiplicative reduction and we disabled them
if (DisableMultiplicativeReductions &&
(BinOp->getOpcode() == Instruction::Mul ||
BinOp->getOpcode() == Instruction::FMul))
return;
// Check the binary operator operands for a candidate load
auto *PossibleLoad0 = dyn_cast<LoadInst>(BinOp->getOperand(0));
auto *PossibleLoad1 = dyn_cast<LoadInst>(BinOp->getOperand(1));
if (!PossibleLoad0 && !PossibleLoad1)
return;
// A load is only a candidate if it cannot escape (thus has only this use)
if (PossibleLoad0 && PossibleLoad0->getNumUses() == 1)
if (PossibleLoad0->getParent() == Store->getParent())
Loads.push_back(&getArrayAccessFor(PossibleLoad0));
if (PossibleLoad1 && PossibleLoad1->getNumUses() == 1)
if (PossibleLoad1->getParent() == Store->getParent())
Loads.push_back(&getArrayAccessFor(PossibleLoad1));
}
/// @brief Check for reductions in this ScopStmt
///
/// Iterate over all store memory accesses and check for valid binary reduction
/// like chains. For all candidates we check if they have the same base address
/// and there are no other accesses which overlap with them. The base address
/// check rules out impossible reductions candidates early. The overlap check,
/// together with the "only one user" check in collectCandiateReductionLoads,
/// guarantees that none of the intermediate results will escape during
/// execution of the loop nest. We basically check here that no other memory
/// access can access the same memory as the potential reduction.
void ScopStmt::checkForReductions() {
SmallVector<MemoryAccess *, 2> Loads;
SmallVector<std::pair<MemoryAccess *, MemoryAccess *>, 4> Candidates;
// First collect candidate load-store reduction chains by iterating over all
// stores and collecting possible reduction loads.
for (MemoryAccess *StoreMA : MemAccs) {
if (StoreMA->isRead())
continue;
Loads.clear();
collectCandiateReductionLoads(StoreMA, Loads);
for (MemoryAccess *LoadMA : Loads)
Candidates.push_back(std::make_pair(LoadMA, StoreMA));
}
// Then check each possible candidate pair.
for (const auto &CandidatePair : Candidates) {
bool Valid = true;
isl_map *LoadAccs = CandidatePair.first->getAccessRelation();
isl_map *StoreAccs = CandidatePair.second->getAccessRelation();
// Skip those with obviously unequal base addresses.
if (!isl_map_has_equal_space(LoadAccs, StoreAccs)) {
isl_map_free(LoadAccs);
isl_map_free(StoreAccs);
continue;
}
// And check if the remaining for overlap with other memory accesses.
isl_map *AllAccsRel = isl_map_union(LoadAccs, StoreAccs);
AllAccsRel = isl_map_intersect_domain(AllAccsRel, getDomain());
isl_set *AllAccs = isl_map_range(AllAccsRel);
for (MemoryAccess *MA : MemAccs) {
if (MA == CandidatePair.first || MA == CandidatePair.second)
continue;
isl_map *AccRel =
isl_map_intersect_domain(MA->getAccessRelation(), getDomain());
isl_set *Accs = isl_map_range(AccRel);
if (isl_set_has_equal_space(AllAccs, Accs) || isl_set_free(Accs)) {
isl_set *OverlapAccs = isl_set_intersect(Accs, isl_set_copy(AllAccs));
Valid = Valid && isl_set_is_empty(OverlapAccs);
isl_set_free(OverlapAccs);
}
}
isl_set_free(AllAccs);
if (!Valid)
continue;
const LoadInst *Load =
dyn_cast<const LoadInst>(CandidatePair.first->getAccessInstruction());
MemoryAccess::ReductionType RT =
getReductionType(dyn_cast<BinaryOperator>(Load->user_back()), Load);
// If no overlapping access was found we mark the load and store as
// reduction like.
CandidatePair.first->markAsReductionLike(RT);
CandidatePair.second->markAsReductionLike(RT);
}
}
std::string ScopStmt::getDomainStr() const { return stringFromIslObj(Domain); }
std::string ScopStmt::getScheduleStr() const {
auto *S = getSchedule();
auto Str = stringFromIslObj(S);
isl_map_free(S);
return Str;
}
void ScopStmt::setInvalidDomain(__isl_take isl_set *ID) {
isl_set_free(InvalidDomain);
InvalidDomain = ID;
}
BasicBlock *ScopStmt::getEntryBlock() const {
if (isBlockStmt())
return getBasicBlock();
return getRegion()->getEntry();
}
unsigned ScopStmt::getNumIterators() const { return NestLoops.size(); }
const char *ScopStmt::getBaseName() const { return BaseName.c_str(); }
Loop *ScopStmt::getLoopForDimension(unsigned Dimension) const {
return NestLoops[Dimension];
}
isl_ctx *ScopStmt::getIslCtx() const { return Parent.getIslCtx(); }
__isl_give isl_set *ScopStmt::getDomain() const { return isl_set_copy(Domain); }
__isl_give isl_space *ScopStmt::getDomainSpace() const {
return isl_set_get_space(Domain);
}
__isl_give isl_id *ScopStmt::getDomainId() const {
return isl_set_get_tuple_id(Domain);
}
ScopStmt::~ScopStmt() {
isl_set_free(Domain);
isl_set_free(InvalidDomain);
}
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::removeMemoryAccess(MemoryAccess *MA) {
// Remove the memory accesses from this statement
// together with all scalar accesses that were caused by it.
// MK_Value READs have no access instruction, hence would not be removed by
// this function. However, it is only used for invariant LoadInst accesses,
// its arguments are always affine, hence synthesizable, and therefore there
// are no MK_Value READ accesses to be removed.
auto Predicate = [&](MemoryAccess *Acc) {
return Acc->getAccessInstruction() == MA->getAccessInstruction();
};
MemAccs.erase(std::remove_if(MemAccs.begin(), MemAccs.end(), Predicate),
MemAccs.end());
InstructionToAccess.erase(MA->getAccessInstruction());
}
//===----------------------------------------------------------------------===//
/// Scop class implement
void Scop::setContext(__isl_take isl_set *NewContext) {
NewContext = isl_set_align_params(NewContext, isl_set_get_space(Context));
isl_set_free(Context);
Context = NewContext;
}
/// @brief Remap parameter values but keep AddRecs valid wrt. invariant loads.
struct SCEVSensitiveParameterRewriter
: public SCEVVisitor<SCEVSensitiveParameterRewriter, const SCEV *> {
ValueToValueMap &VMap;
ScalarEvolution &SE;
public:
SCEVSensitiveParameterRewriter(ValueToValueMap &VMap, ScalarEvolution &SE)
: VMap(VMap), SE(SE) {}
static const SCEV *rewrite(const SCEV *E, ScalarEvolution &SE,
ValueToValueMap &VMap) {
SCEVSensitiveParameterRewriter SSPR(VMap, SE);
return SSPR.visit(E);
}
const SCEV *visit(const SCEV *E) {
return SCEVVisitor<SCEVSensitiveParameterRewriter, const SCEV *>::visit(E);
}
const SCEV *visitConstant(const SCEVConstant *E) { return E; }
const SCEV *visitTruncateExpr(const SCEVTruncateExpr *E) {
return SE.getTruncateExpr(visit(E->getOperand()), E->getType());
}
const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *E) {
return SE.getZeroExtendExpr(visit(E->getOperand()), E->getType());
}
const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *E) {
return SE.getSignExtendExpr(visit(E->getOperand()), E->getType());
}
const SCEV *visitAddExpr(const SCEVAddExpr *E) {
SmallVector<const SCEV *, 4> Operands;
for (int i = 0, e = E->getNumOperands(); i < e; ++i)
Operands.push_back(visit(E->getOperand(i)));
return SE.getAddExpr(Operands);
}
const SCEV *visitMulExpr(const SCEVMulExpr *E) {
SmallVector<const SCEV *, 4> Operands;
for (int i = 0, e = E->getNumOperands(); i < e; ++i)
Operands.push_back(visit(E->getOperand(i)));
return SE.getMulExpr(Operands);
}
const SCEV *visitSMaxExpr(const SCEVSMaxExpr *E) {
SmallVector<const SCEV *, 4> Operands;
for (int i = 0, e = E->getNumOperands(); i < e; ++i)
Operands.push_back(visit(E->getOperand(i)));
return SE.getSMaxExpr(Operands);
}
const SCEV *visitUMaxExpr(const SCEVUMaxExpr *E) {
SmallVector<const SCEV *, 4> Operands;
for (int i = 0, e = E->getNumOperands(); i < e; ++i)
Operands.push_back(visit(E->getOperand(i)));
return SE.getUMaxExpr(Operands);
}
const SCEV *visitUDivExpr(const SCEVUDivExpr *E) {
return SE.getUDivExpr(visit(E->getLHS()), visit(E->getRHS()));
}
const SCEV *visitAddRecExpr(const SCEVAddRecExpr *E) {
auto *Start = visit(E->getStart());
auto *AddRec = SE.getAddRecExpr(SE.getConstant(E->getType(), 0),
visit(E->getStepRecurrence(SE)),
E->getLoop(), SCEV::FlagAnyWrap);
return SE.getAddExpr(Start, AddRec);
}
const SCEV *visitUnknown(const SCEVUnknown *E) {
if (auto *NewValue = VMap.lookup(E->getValue()))
return SE.getUnknown(NewValue);
return E;
}
};
const SCEV *Scop::getRepresentingInvariantLoadSCEV(const SCEV *S) {
return SCEVSensitiveParameterRewriter::rewrite(S, *SE, InvEquivClassVMap);
}
void Scop::createParameterId(const SCEV *Parameter) {
assert(Parameters.count(Parameter));
assert(!ParameterIds.count(Parameter));
std::string ParameterName = "p_" + std::to_string(getNumParams() - 1);
if (const SCEVUnknown *ValueParameter = dyn_cast<SCEVUnknown>(Parameter)) {
Value *Val = ValueParameter->getValue();
// If this parameter references a specific Value and this value has a name
// we use this name as it is likely to be unique and more useful than just
// a number.
if (Val->hasName())
ParameterName = Val->getName();
else if (LoadInst *LI = dyn_cast<LoadInst>(Val)) {
auto *LoadOrigin = LI->getPointerOperand()->stripInBoundsOffsets();
if (LoadOrigin->hasName()) {
ParameterName += "_loaded_from_";
ParameterName +=
LI->getPointerOperand()->stripInBoundsOffsets()->getName();
}
}
}
ParameterName = getIslCompatibleName("", ParameterName, "");
auto *Id = isl_id_alloc(getIslCtx(), ParameterName.c_str(),
const_cast<void *>((const void *)Parameter));
ParameterIds[Parameter] = Id;
}
void Scop::addParams(const ParameterSetTy &NewParameters) {
for (const SCEV *Parameter : NewParameters) {
// Normalize the SCEV to get the representing element for an invariant load.
Parameter = extractConstantFactor(Parameter, *SE).second;
Parameter = getRepresentingInvariantLoadSCEV(Parameter);
if (Parameters.insert(Parameter))
createParameterId(Parameter);
}
}
__isl_give isl_id *Scop::getIdForParam(const SCEV *Parameter) {
// Normalize the SCEV to get the representing element for an invariant load.
Parameter = getRepresentingInvariantLoadSCEV(Parameter);
return isl_id_copy(ParameterIds.lookup(Parameter));
}
__isl_give isl_set *Scop::addNonEmptyDomainConstraints(isl_set *C) const {
isl_set *DomainContext = isl_union_set_params(getDomains());
return isl_set_intersect_params(C, DomainContext);
}
bool Scop::isDominatedBy(const DominatorTree &DT, BasicBlock *BB) const {
return DT.dominates(BB, getEntry());
}
void Scop::addUserAssumptions(AssumptionCache &AC, DominatorTree &DT,
LoopInfo &LI) {
auto &F = getFunction();
for (auto &Assumption : AC.assumptions()) {
auto *CI = dyn_cast_or_null<CallInst>(Assumption);
if (!CI || CI->getNumArgOperands() != 1)
continue;
bool InScop = contains(CI);
if (!InScop && !isDominatedBy(DT, CI->getParent()))
continue;
auto *L = LI.getLoopFor(CI->getParent());
auto *Val = CI->getArgOperand(0);
ParameterSetTy DetectedParams;
if (!isAffineConstraint(Val, &R, L, *SE, DetectedParams)) {
emitOptimizationRemarkAnalysis(F.getContext(), DEBUG_TYPE, F,
CI->getDebugLoc(),
"Non-affine user assumption ignored.");
continue;
}
// Collect all newly introduced parameters.
ParameterSetTy NewParams;
for (auto *Param : DetectedParams) {
Param = extractConstantFactor(Param, *SE).second;
Param = getRepresentingInvariantLoadSCEV(Param);
if (Parameters.count(Param))
continue;
NewParams.insert(Param);
}
SmallVector<isl_set *, 2> ConditionSets;
auto *TI = InScop ? CI->getParent()->getTerminator() : nullptr;
auto &Stmt = InScop ? *getStmtFor(CI->getParent()) : *Stmts.begin();
auto *Dom = InScop ? getDomainConditions(&Stmt) : isl_set_copy(Context);
bool Valid = buildConditionSets(Stmt, Val, TI, L, Dom, ConditionSets);
isl_set_free(Dom);
if (!Valid)
continue;
isl_set *AssumptionCtx = nullptr;
if (InScop) {
AssumptionCtx = isl_set_complement(isl_set_params(ConditionSets[1]));
isl_set_free(ConditionSets[0]);
} else {
AssumptionCtx = isl_set_complement(ConditionSets[1]);
AssumptionCtx = isl_set_intersect(AssumptionCtx, ConditionSets[0]);
}
// Project out newly introduced parameters as they are not otherwise useful.
if (!NewParams.empty()) {
for (unsigned u = 0; u < isl_set_n_param(AssumptionCtx); u++) {
auto *Id = isl_set_get_dim_id(AssumptionCtx, isl_dim_param, u);
auto *Param = static_cast<const SCEV *>(isl_id_get_user(Id));
isl_id_free(Id);
if (!NewParams.count(Param))
continue;
AssumptionCtx =
isl_set_project_out(AssumptionCtx, isl_dim_param, u--, 1);
}
}
emitOptimizationRemarkAnalysis(
F.getContext(), DEBUG_TYPE, F, CI->getDebugLoc(),
"Use user assumption: " + stringFromIslObj(AssumptionCtx));
Context = isl_set_intersect(Context, AssumptionCtx);
}
}
void Scop::addUserContext() {
if (UserContextStr.empty())
return;
isl_set *UserContext =
isl_set_read_from_str(getIslCtx(), UserContextStr.c_str());
isl_space *Space = getParamSpace();
if (isl_space_dim(Space, isl_dim_param) !=
isl_set_dim(UserContext, isl_dim_param)) {
auto SpaceStr = isl_space_to_str(Space);
errs() << "Error: the context provided in -polly-context has not the same "
<< "number of dimensions than the computed context. Due to this "
<< "mismatch, the -polly-context option is ignored. Please provide "
<< "the context in the parameter space: " << SpaceStr << ".\n";
free(SpaceStr);
isl_set_free(UserContext);
isl_space_free(Space);
return;
}
for (unsigned i = 0; i < isl_space_dim(Space, isl_dim_param); i++) {
auto *NameContext = isl_set_get_dim_name(Context, isl_dim_param, i);
auto *NameUserContext = isl_set_get_dim_name(UserContext, isl_dim_param, i);
if (strcmp(NameContext, NameUserContext) != 0) {
auto SpaceStr = isl_space_to_str(Space);
errs() << "Error: the name of dimension " << i
<< " provided in -polly-context "
<< "is '" << NameUserContext << "', but the name in the computed "
<< "context is '" << NameContext
<< "'. Due to this name mismatch, "
<< "the -polly-context option is ignored. Please provide "
<< "the context in the parameter space: " << SpaceStr << ".\n";
free(SpaceStr);
isl_set_free(UserContext);
isl_space_free(Space);
return;
}
UserContext =
isl_set_set_dim_id(UserContext, isl_dim_param, i,
isl_space_get_dim_id(Space, isl_dim_param, i));
}
Context = isl_set_intersect(Context, UserContext);
isl_space_free(Space);
}
void Scop::buildInvariantEquivalenceClasses() {
DenseMap<std::pair<const SCEV *, Type *>, LoadInst *> EquivClasses;
const InvariantLoadsSetTy &RIL = getRequiredInvariantLoads();
for (LoadInst *LInst : RIL) {
const SCEV *PointerSCEV = SE->getSCEV(LInst->getPointerOperand());
Type *Ty = LInst->getType();
LoadInst *&ClassRep = EquivClasses[std::make_pair(PointerSCEV, Ty)];
if (ClassRep) {
InvEquivClassVMap[LInst] = ClassRep;
continue;
}
ClassRep = LInst;
InvariantEquivClasses.emplace_back(PointerSCEV, MemoryAccessList(), nullptr,
Ty);
}
}
void Scop::buildContext() {
isl_space *Space = isl_space_params_alloc(getIslCtx(), 0);
Context = isl_set_universe(isl_space_copy(Space));
InvalidContext = isl_set_empty(isl_space_copy(Space));
AssumedContext = isl_set_universe(Space);
}
void Scop::addParameterBounds() {
unsigned PDim = 0;
for (auto *Parameter : Parameters) {
ConstantRange SRange = SE->getSignedRange(Parameter);
Context = addRangeBoundsToSet(Context, SRange, PDim++, isl_dim_param);
}
}
void Scop::realignParams() {
// Add all parameters into a common model.
isl_space *Space = isl_space_params_alloc(getIslCtx(), ParameterIds.size());
unsigned PDim = 0;
for (const auto *Parameter : Parameters) {
isl_id *id = getIdForParam(Parameter);
Space = isl_space_set_dim_id(Space, isl_dim_param, PDim++, id);
}
// Align the parameters of all data structures to the model.
Context = isl_set_align_params(Context, Space);
// As all parameters are known add bounds to them.
addParameterBounds();
for (ScopStmt &Stmt : *this)
Stmt.realignParams();
// Simplify the schedule according to the context too.
Schedule = isl_schedule_gist_domain_params(Schedule, getContext());
}
static __isl_give isl_set *
simplifyAssumptionContext(__isl_take isl_set *AssumptionContext,
const Scop &S) {
// If we modelt all blocks in the SCoP that have side effects we can simplify
// the context with the constraints that are needed for anything to be
// executed at all. However, if we have error blocks in the SCoP we already
// assumed some parameter combinations cannot occure and removed them from the
// domains, thus we cannot use the remaining domain to simplify the
// assumptions.
if (!S.hasErrorBlock()) {
isl_set *DomainParameters = isl_union_set_params(S.getDomains());
AssumptionContext =
isl_set_gist_params(AssumptionContext, DomainParameters);
}
AssumptionContext = isl_set_gist_params(AssumptionContext, S.getContext());
return AssumptionContext;
}
void Scop::simplifyContexts() {
// The parameter constraints of the iteration domains give us a set of
// constraints that need to hold for all cases where at least a single
// statement iteration is executed in the whole scop. We now simplify the
// assumed context under the assumption that such constraints hold and at
// least a single statement iteration is executed. For cases where no
// statement instances are executed, the assumptions we have taken about
// the executed code do not matter and can be changed.
//
// WARNING: This only holds if the assumptions we have taken do not reduce
// the set of statement instances that are executed. Otherwise we
// may run into a case where the iteration domains suggest that
// for a certain set of parameter constraints no code is executed,
// but in the original program some computation would have been
// performed. In such a case, modifying the run-time conditions and
// possibly influencing the run-time check may cause certain scops
// to not be executed.
//
// Example:
//
// When delinearizing the following code:
//
// for (long i = 0; i < 100; i++)
// for (long j = 0; j < m; j++)
// A[i+p][j] = 1.0;
//
// we assume that the condition m <= 0 or (m >= 1 and p >= 0) holds as
// otherwise we would access out of bound data. Now, knowing that code is
// only executed for the case m >= 0, it is sufficient to assume p >= 0.
AssumedContext = simplifyAssumptionContext(AssumedContext, *this);
InvalidContext = isl_set_align_params(InvalidContext, getParamSpace());
}
/// @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;
Set = isl_set_remove_divs(Set);
if (isl_set_n_basic_set(Set) >= MaxDisjunctionsInDomain) {
isl_set_free(Set);
return isl_stat_error;
}
// 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;
}
}
MinPMA = isl_set_lexmin_pw_multi_aff(isl_set_copy(Set));
MaxPMA = isl_set_lexmax_pw_multi_aff(isl_set_copy(Set));
MinPMA = isl_pw_multi_aff_coalesce(MinPMA);
MaxPMA = isl_pw_multi_aff_coalesce(MaxPMA);
// Adjust the last dimension of the maximal access by one as we want to
// enclose the accessed memory region by MinPMA and MaxPMA. The pointer
// we test during code generation might now point after the end of the
// allocated array but we will never dereference it anyway.
assert(isl_pw_multi_aff_dim(MaxPMA, isl_dim_out) &&
"Assumed at least one output dimension");
Pos = isl_pw_multi_aff_dim(MaxPMA, isl_dim_out) - 1;
LastDimAff = isl_pw_multi_aff_get_pw_aff(MaxPMA, Pos);
OneAff = isl_aff_zero_on_domain(
isl_local_space_from_space(isl_pw_aff_get_domain_space(LastDimAff)));
OneAff = isl_aff_add_constant_si(OneAff, 1);
LastDimAff = isl_pw_aff_add(LastDimAff, isl_pw_aff_from_aff(OneAff));
MaxPMA = isl_pw_multi_aff_set_pw_aff(MaxPMA, Pos, LastDimAff);
MinMaxAccesses->push_back(std::make_pair(MinPMA, MaxPMA));
isl_set_free(Set);
return isl_stat_ok;
}
static __isl_give isl_set *getAccessDomain(MemoryAccess *MA) {
isl_set *Domain = MA->getStatement()->getDomain();
Domain = isl_set_project_out(Domain, isl_dim_set, 0, isl_set_n_dim(Domain));
return isl_set_reset_tuple_id(Domain);
}
/// @brief Wrapper function to calculate minimal/maximal accesses to each array.
static bool calculateMinMaxAccess(__isl_take isl_union_map *Accesses,
__isl_take isl_union_set *Domains,
Scop::MinMaxVectorTy &MinMaxAccesses) {
Accesses = isl_union_map_intersect_domain(Accesses, Domains);
isl_union_set *Locations = isl_union_map_range(Accesses);
Locations = isl_union_set_coalesce(Locations);
Locations = isl_union_set_detect_equalities(Locations);
bool Valid = (0 == isl_union_set_foreach_set(Locations, buildMinMaxAccess,
&MinMaxAccesses));
isl_union_set_free(Locations);
return Valid;
}
/// @brief Helper to treat non-affine regions and basic blocks the same.
///
///{
/// @brief Return the block that is the representing block for @p RN.
static inline BasicBlock *getRegionNodeBasicBlock(RegionNode *RN) {
return RN->isSubRegion() ? RN->getNodeAs<Region>()->getEntry()
: RN->getNodeAs<BasicBlock>();
}
/// @brief Return the @p idx'th block that is executed after @p RN.
static inline BasicBlock *
getRegionNodeSuccessor(RegionNode *RN, TerminatorInst *TI, unsigned idx) {
if (RN->isSubRegion()) {
assert(idx == 0);
return RN->getNodeAs<Region>()->getExit();
}
return TI->getSuccessor(idx);
}
/// @brief Return the smallest loop surrounding @p RN.
static inline Loop *getRegionNodeLoop(RegionNode *RN, LoopInfo &LI) {
if (!RN->isSubRegion())
return LI.getLoopFor(RN->getNodeAs<BasicBlock>());
Region *NonAffineSubRegion = RN->getNodeAs<Region>();
Loop *L = LI.getLoopFor(NonAffineSubRegion->getEntry());
while (L && NonAffineSubRegion->contains(L))
L = L->getParentLoop();
return L;
}
static inline unsigned getNumBlocksInRegionNode(RegionNode *RN) {
if (!RN->isSubRegion())
return 1;
Region *R = RN->getNodeAs<Region>();
return std::distance(R->block_begin(), R->block_end());
}
static bool containsErrorBlock(RegionNode *RN, const Region &R, LoopInfo &LI,
const DominatorTree &DT) {
if (!RN->isSubRegion())
return isErrorBlock(*RN->getNodeAs<BasicBlock>(), R, LI, DT);
for (BasicBlock *BB : RN->getNodeAs<Region>()->blocks())
if (isErrorBlock(*BB, R, LI, DT))
return true;
return false;
}
///}
static inline __isl_give isl_set *addDomainDimId(__isl_take isl_set *Domain,
unsigned Dim, Loop *L) {
Domain = isl_set_lower_bound_si(Domain, isl_dim_set, Dim, -1);
isl_id *DimId =
isl_id_alloc(isl_set_get_ctx(Domain), nullptr, static_cast<void *>(L));
return isl_set_set_dim_id(Domain, isl_dim_set, Dim, DimId);
}
__isl_give isl_set *Scop::getDomainConditions(const ScopStmt *Stmt) const {
return getDomainConditions(Stmt->getEntryBlock());
}
__isl_give isl_set *Scop::getDomainConditions(BasicBlock *BB) const {
auto DIt = DomainMap.find(BB);
if (DIt != DomainMap.end())
return isl_set_copy(DIt->getSecond());
auto &RI = *R.getRegionInfo();
auto *BBR = RI.getRegionFor(BB);
while (BBR->getEntry() == BB)
BBR = BBR->getParent();
return getDomainConditions(BBR->getEntry());
}
bool Scop::buildDomains(Region *R, DominatorTree &DT, LoopInfo &LI) {
bool IsOnlyNonAffineRegion = isNonAffineSubRegion(R);
auto *EntryBB = R->getEntry();
auto *L = IsOnlyNonAffineRegion ? nullptr : LI.getLoopFor(EntryBB);
int LD = getRelativeLoopDepth(L);
auto *S = isl_set_universe(isl_space_set_alloc(getIslCtx(), 0, LD + 1));
while (LD-- >= 0) {
S = addDomainDimId(S, LD + 1, L);
L = L->getParentLoop();
}
// Initialize the invalid domain.
auto *EntryStmt = getStmtFor(EntryBB);
EntryStmt->setInvalidDomain(isl_set_empty(isl_set_get_space(S)));
DomainMap[EntryBB] = S;
if (IsOnlyNonAffineRegion)
return !containsErrorBlock(R->getNode(), *R, LI, DT);
if (!buildDomainsWithBranchConstraints(R, DT, LI))
return false;
if (!propagateDomainConstraints(R, DT, LI))
return false;
// Error blocks and blocks dominated by them have been assumed to never be
// executed. Representing them in the Scop does not add any value. In fact,
// it is likely to cause issues during construction of the ScopStmts. The
// contents of error blocks have not been verified to be expressible and
// will cause problems when building up a ScopStmt for them.
// Furthermore, basic blocks dominated by error blocks may reference
// instructions in the error block which, if the error block is not modeled,
// can themselves not be constructed properly. To this end we will replace
// the domains of error blocks and those only reachable via error blocks
// with an empty set. Additionally, we will record for each block under which
// parameter combination it would be reached via an error block in its
// InvalidDomain. This information is needed during load hoisting.
if (!propagateInvalidStmtDomains(R, DT, LI))
return false;
return true;
}
// If the loop is nonaffine/boxed, return the first non-boxed surrounding loop
// for Polly. If the loop is affine, return the loop itself. Do not call
// `getSCEVAtScope()` on the result of `getFirstNonBoxedLoopFor()`, as we need
// to analyze the memory accesses of the nonaffine/boxed loops.
static Loop *getFirstNonBoxedLoopFor(BasicBlock *BB, LoopInfo &LI,
const BoxedLoopsSetTy &BoxedLoops) {
auto *L = LI.getLoopFor(BB);
while (BoxedLoops.count(L))
L = L->getParentLoop();
return L;
}
/// @brief Adjust the dimensions of @p Dom that was constructed for @p OldL
/// to be compatible to domains constructed for loop @p NewL.
///
/// This function assumes @p NewL and @p OldL are equal or there is a CFG
/// edge from @p OldL to @p NewL.
static __isl_give isl_set *adjustDomainDimensions(Scop &S,
__isl_take isl_set *Dom,
Loop *OldL, Loop *NewL) {
// If the loops are the same there is nothing to do.
if (NewL == OldL)
return Dom;
int OldDepth = S.getRelativeLoopDepth(OldL);
int NewDepth = S.getRelativeLoopDepth(NewL);
// If both loops are non-affine loops there is nothing to do.
if (OldDepth == -1 && NewDepth == -1)
return Dom;
// Distinguish three cases:
// 1) The depth is the same but the loops are not.
// => One loop was left one was entered.
// 2) The depth increased from OldL to NewL.
// => One loop was entered, none was left.
// 3) The depth decreased from OldL to NewL.
// => Loops were left were difference of the depths defines how many.
if (OldDepth == NewDepth) {
assert(OldL->getParentLoop() == NewL->getParentLoop());
Dom = isl_set_project_out(Dom, isl_dim_set, NewDepth, 1);
Dom = isl_set_add_dims(Dom, isl_dim_set, 1);
Dom = addDomainDimId(Dom, NewDepth, NewL);
} else if (OldDepth < NewDepth) {
assert(OldDepth + 1 == NewDepth);
auto &R = S.getRegion();
(void)R;
assert(NewL->getParentLoop() == OldL ||
((!OldL || !R.contains(OldL)) && R.contains(NewL)));
Dom = isl_set_add_dims(Dom, isl_dim_set, 1);
Dom = addDomainDimId(Dom, NewDepth, NewL);
} else {
assert(OldDepth > NewDepth);
int Diff = OldDepth - NewDepth;
int NumDim = isl_set_n_dim(Dom);
assert(NumDim >= Diff);
Dom = isl_set_project_out(Dom, isl_dim_set, NumDim - Diff, Diff);
}
return Dom;
}
bool Scop::propagateInvalidStmtDomains(Region *R, DominatorTree &DT,
LoopInfo &LI) {
auto &BoxedLoops = getBoxedLoops();
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 (!isNonAffineSubRegion(SubRegion)) {
propagateInvalidStmtDomains(SubRegion, DT, LI);
continue;
}
}
bool ContainsErrorBlock = containsErrorBlock(RN, getRegion(), LI, DT);
BasicBlock *BB = getRegionNodeBasicBlock(RN);
ScopStmt *Stmt = getStmtFor(BB);
isl_set *&Domain = DomainMap[BB];
assert(Domain && "Cannot propagate a nullptr");
auto *InvalidDomain = Stmt->getInvalidDomain();
bool IsInvalidBlock =
ContainsErrorBlock || isl_set_is_subset(Domain, InvalidDomain);
if (!IsInvalidBlock) {
InvalidDomain = isl_set_intersect(InvalidDomain, isl_set_copy(Domain));
} else {
isl_set_free(InvalidDomain);
InvalidDomain = Domain;
isl_set *DomPar = isl_set_params(isl_set_copy(Domain));
recordAssumption(ERRORBLOCK, DomPar, BB->getTerminator()->getDebugLoc(),
AS_RESTRICTION);
Domain = nullptr;
}
if (isl_set_is_empty(InvalidDomain)) {
Stmt->setInvalidDomain(InvalidDomain);
continue;
}
auto *BBLoop = getRegionNodeLoop(RN, LI);
auto *TI = BB->getTerminator();
unsigned NumSuccs = RN->isSubRegion() ? 1 : TI->getNumSuccessors();
for (unsigned u = 0; u < NumSuccs; u++) {
auto *SuccBB = getRegionNodeSuccessor(RN, TI, u);
auto *SuccStmt = getStmtFor(SuccBB);
// Skip successors outside the SCoP.
if (!SuccStmt)
continue;
// Skip backedges.
if (DT.dominates(SuccBB, BB))
continue;
auto *SuccBBLoop = getFirstNonBoxedLoopFor(SuccBB, LI, BoxedLoops);
auto *AdjustedInvalidDomain = adjustDomainDimensions(
*this, isl_set_copy(InvalidDomain), BBLoop, SuccBBLoop);
auto *SuccInvalidDomain = SuccStmt->getInvalidDomain();
SuccInvalidDomain =
isl_set_union(SuccInvalidDomain, AdjustedInvalidDomain);
SuccInvalidDomain = isl_set_coalesce(SuccInvalidDomain);
unsigned NumConjucts = isl_set_n_basic_set(SuccInvalidDomain);
SuccStmt->setInvalidDomain(SuccInvalidDomain);
// Check if the maximal number of domain disjunctions was reached.
// In case this happens we will bail.
if (NumConjucts < MaxDisjunctionsInDomain)
continue;
isl_set_free(InvalidDomain);
invalidate(COMPLEXITY, TI->getDebugLoc());
return false;
}
Stmt->setInvalidDomain(InvalidDomain);
}
return true;
}
void Scop::propagateDomainConstraintsToRegionExit(
BasicBlock *BB, Loop *BBLoop,
SmallPtrSetImpl<BasicBlock *> &FinishedExitBlocks, LoopInfo &LI) {
// Check if the block @p BB is the entry of a region. If so we propagate it's
// domain to the exit block of the region. Otherwise we are done.
auto *RI = R.getRegionInfo();
auto *BBReg = RI ? RI->getRegionFor(BB) : nullptr;
auto *ExitBB = BBReg ? BBReg->getExit() : nullptr;
if (!BBReg || BBReg->getEntry() != BB || !contains(ExitBB))
return;
auto &BoxedLoops = getBoxedLoops();
// Do not propagate the domain if there is a loop backedge inside the region
// that would prevent the exit block from beeing executed.
auto *L = BBLoop;
while (L && contains(L)) {
SmallVector<BasicBlock *, 4> LatchBBs;
BBLoop->getLoopLatches(LatchBBs);
for (auto *LatchBB : LatchBBs)
if (BB != LatchBB && BBReg->contains(LatchBB))
return;
L = L->getParentLoop();
}
auto *Domain = DomainMap[BB];
assert(Domain && "Cannot propagate a nullptr");
auto *ExitBBLoop = getFirstNonBoxedLoopFor(ExitBB, LI, BoxedLoops);
// Since the dimensions of @p BB and @p ExitBB might be different we have to
// adjust the domain before we can propagate it.
auto *AdjustedDomain =
adjustDomainDimensions(*this, isl_set_copy(Domain), BBLoop, ExitBBLoop);
auto *&ExitDomain = DomainMap[ExitBB];
// If the exit domain is not yet created we set it otherwise we "add" the
// current domain.
ExitDomain =
ExitDomain ? isl_set_union(AdjustedDomain, ExitDomain) : AdjustedDomain;
// Initialize the invalid domain.
auto *ExitStmt = getStmtFor(ExitBB);
ExitStmt->setInvalidDomain(isl_set_empty(isl_set_get_space(ExitDomain)));
FinishedExitBlocks.insert(ExitBB);
}
bool Scop::buildDomainsWithBranchConstraints(Region *R, DominatorTree &DT,
LoopInfo &LI) {
// 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.
SmallPtrSet<BasicBlock *, 8> FinishedExitBlocks;
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 (!isNonAffineSubRegion(SubRegion)) {
if (!buildDomainsWithBranchConstraints(SubRegion, DT, LI))
return false;
continue;
}
}
if (containsErrorBlock(RN, getRegion(), LI, DT))
HasErrorBlock = true;
BasicBlock *BB = getRegionNodeBasicBlock(RN);
TerminatorInst *TI = BB->getTerminator();
if (isa<UnreachableInst>(TI))
continue;
isl_set *Domain = DomainMap.lookup(BB);
if (!Domain)
continue;
MaxLoopDepth = std::max(MaxLoopDepth, isl_set_n_dim(Domain));
auto *BBLoop = getRegionNodeLoop(RN, LI);
// Propagate the domain from BB directly to blocks that have a superset
// domain, at the moment only region exit nodes of regions that start in BB.
propagateDomainConstraintsToRegionExit(BB, BBLoop, FinishedExitBlocks, LI);
// If all successors of BB have been set a domain through the propagation
// above we do not need to build condition sets but can just skip this
// block. However, it is important to note that this is a local property
// with regards to the region @p R. To this end FinishedExitBlocks is a
// local variable.
auto IsFinishedRegionExit = [&FinishedExitBlocks](BasicBlock *SuccBB) {
return FinishedExitBlocks.count(SuccBB);
};
if (std::all_of(succ_begin(BB), succ_end(BB), IsFinishedRegionExit))
continue;
// 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 if (!buildConditionSets(*getStmtFor(BB), TI, BBLoop, Domain,
ConditionSets))
return false;
// 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);
auto *SuccStmt = getStmtFor(SuccBB);
// Skip blocks outside the region.
if (!SuccStmt) {
isl_set_free(CondSet);
continue;
}
// If we propagate the domain of some block to "SuccBB" we do not have to
// adjust the domain.
if (FinishedExitBlocks.count(SuccBB)) {
isl_set_free(CondSet);
continue;
}
// Skip back edges.
if (DT.dominates(SuccBB, BB)) {
isl_set_free(CondSet);
continue;
}
auto &BoxedLoops = getBoxedLoops();
auto *SuccBBLoop = getFirstNonBoxedLoopFor(SuccBB, LI, BoxedLoops);
CondSet = adjustDomainDimensions(*this, CondSet, BBLoop, 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 = isl_set_coalesce(isl_set_union(SuccDomain, CondSet));
} else {
// Initialize the invalid domain.
SuccStmt->setInvalidDomain(isl_set_empty(isl_set_get_space(CondSet)));
SuccDomain = CondSet;
}
// Check if the maximal number of domain disjunctions was reached.
// In case this happens we will clean up and bail.
if (isl_set_n_basic_set(SuccDomain) < MaxDisjunctionsInDomain)
continue;
invalidate(COMPLEXITY, DebugLoc());
while (++u < ConditionSets.size())
isl_set_free(ConditionSets[u]);
return false;
}
}
return true;
}
__isl_give isl_set *Scop::getPredecessorDomainConstraints(BasicBlock *BB,
isl_set *Domain,
DominatorTree &DT,
LoopInfo &LI) {
// If @p BB is the ScopEntry we are done
if (R.getEntry() == BB)
return isl_set_universe(isl_set_get_space(Domain));
// The set of boxed loops (loops in non-affine subregions) for this SCoP.
auto &BoxedLoops = getBoxedLoops();
// The region info of this function.
auto &RI = *R.getRegionInfo();
auto *BBLoop = getFirstNonBoxedLoopFor(BB, LI, BoxedLoops);
// A domain to collect all predecessor domains, thus all conditions under
// which the block is executed. To this end we start with the empty domain.
isl_set *PredDom = isl_set_empty(isl_set_get_space(Domain));
// Set of regions of which the entry block domain has been propagated to BB.
// all predecessors inside any of the regions can be skipped.
SmallSet<Region *, 8> PropagatedRegions;
for (auto *PredBB : predecessors(BB)) {
// Skip backedges.
if (DT.dominates(BB, PredBB))
continue;
// If the predecessor is in a region we used for propagation we can skip it.
auto PredBBInRegion = [PredBB](Region *PR) { return PR->contains(PredBB); };
if (std::any_of(PropagatedRegions.begin(), PropagatedRegions.end(),
PredBBInRegion)) {
continue;
}
// Check if there is a valid region we can use for propagation, thus look
// for a region that contains the predecessor and has @p BB as exit block.
auto *PredR = RI.getRegionFor(PredBB);
while (PredR->getExit() != BB && !PredR->contains(BB))
PredR->getParent();
// If a valid region for propagation was found use the entry of that region
// for propagation, otherwise the PredBB directly.
if (PredR->getExit() == BB) {
PredBB = PredR->getEntry();
PropagatedRegions.insert(PredR);
}
auto *PredBBDom = getDomainConditions(PredBB);
auto *PredBBLoop = getFirstNonBoxedLoopFor(PredBB, LI, BoxedLoops);
PredBBDom = adjustDomainDimensions(*this, PredBBDom, PredBBLoop, BBLoop);
PredDom = isl_set_union(PredDom, PredBBDom);
}
return PredDom;
}
bool Scop::propagateDomainConstraints(Region *R, DominatorTree &DT,
LoopInfo &LI) {
// 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.
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 (!isNonAffineSubRegion(SubRegion)) {
if (!propagateDomainConstraints(SubRegion, DT, LI))
return false;
continue;
}
}
BasicBlock *BB = getRegionNodeBasicBlock(RN);
isl_set *&Domain = DomainMap[BB];
assert(Domain);
// Under the union of all predecessor conditions we can reach this block.
auto *PredDom = getPredecessorDomainConstraints(BB, Domain, DT, LI);
Domain = isl_set_coalesce(isl_set_intersect(Domain, PredDom));
Domain = isl_set_align_params(Domain, getParamSpace());
Loop *BBLoop = getRegionNodeLoop(RN, LI);
if (BBLoop && BBLoop->getHeader() == BB && contains(BBLoop))
if (!addLoopBoundsToHeaderDomain(BBLoop, LI))
return false;
}
return true;
}
/// @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;
}
bool 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) {
// If the latch is only reachable via error statements we skip it.
isl_set *LatchBBDom = DomainMap.lookup(LatchBB);
if (!LatchBBDom)
continue;
isl_set *BackedgeCondition = nullptr;
TerminatorInst *TI = LatchBB->getTerminator();
BranchInst *BI = dyn_cast<BranchInst>(TI);
if (BI && BI->isUnconditional())
BackedgeCondition = isl_set_copy(LatchBBDom);
else {
SmallVector<isl_set *, 8> ConditionSets;
int idx = BI->getSuccessor(0) != HeaderBB;
if (!buildConditionSets(*getStmtFor(LatchBB), TI, L, LatchBBDom,
ConditionSets))
return false;
// 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 true;
}
isl_set *UnboundedCtx = isl_set_params(Parts.first);
recordAssumption(INFINITELOOP, UnboundedCtx,
HeaderBB->getTerminator()->getDebugLoc(), AS_RESTRICTION);
return true;
}
MemoryAccess *Scop::lookupBasePtrAccess(MemoryAccess *MA) {
auto *BaseAddr = SE->getSCEV(MA->getBaseAddr());
auto *PointerBase = dyn_cast<SCEVUnknown>(SE->getPointerBase(BaseAddr));
if (!PointerBase)
return nullptr;
auto *PointerBaseInst = dyn_cast<Instruction>(PointerBase->getValue());
if (!PointerBaseInst)
return nullptr;
auto *BasePtrStmt = getStmtFor(PointerBaseInst);
if (!BasePtrStmt)
return nullptr;
return BasePtrStmt->getArrayAccessOrNULLFor(PointerBaseInst);
}
bool Scop::hasNonHoistableBasePtrInScop(MemoryAccess *MA,
__isl_keep isl_union_map *Writes) {
if (auto *BasePtrMA = lookupBasePtrAccess(MA)) {
auto *NHCtx = getNonHoistableCtx(BasePtrMA, Writes);
bool Hoistable = NHCtx != nullptr;
isl_set_free(NHCtx);
return !Hoistable;
}
auto *BaseAddr = SE->getSCEV(MA->getBaseAddr());
auto *PointerBase = dyn_cast<SCEVUnknown>(SE->getPointerBase(BaseAddr));
if (auto *BasePtrInst = dyn_cast<Instruction>(PointerBase->getValue()))
if (!isa<LoadInst>(BasePtrInst))
return contains(BasePtrInst);
return false;
}
bool Scop::buildAliasChecks(AliasAnalysis &AA) {
if (!PollyUseRuntimeAliasChecks)
return true;
if (buildAliasGroups(AA))
return true;
// If a problem occurs while building the alias groups we need to delete
// this SCoP and pretend it wasn't valid in the first place. To this end
// we make the assumed context infeasible.
invalidate(ALIASING, DebugLoc());
DEBUG(dbgs() << "\n\nNOTE: Run time checks for " << getNameStr()
<< " could not be created as the number of parameters involved "
"is too high. The SCoP will be "
"dismissed.\nUse:\n\t--polly-rtc-max-parameters=X\nto adjust "
"the maximal number of parameters but be advised that the "
"compile time might increase exponentially.\n\n");
return false;
}
bool Scop::buildAliasGroups(AliasAnalysis &AA) {
// To create sound alias checks we perform the following steps:
// o) Use the alias analysis and an alias set tracker to build alias sets
// for all memory accesses inside the SCoP.
// o) For each alias set we then map the aliasing pointers back to the
// memory accesses we know, thus obtain groups of memory accesses which
// might alias.
// o) We divide each group based on the domains of the minimal/maximal
// accesses. That means two minimal/maximal accesses are only in a group
// if their access domains intersect, otherwise they are in different
// ones.
// o) We partition each group into read only and non read only accesses.
// o) For each group with more than one base pointer we then compute minimal
// and maximal accesses to each array of a group in read only and non
// read only partitions separately.
using AliasGroupTy = SmallVector<MemoryAccess *, 4>;
AliasSetTracker AST(AA);
DenseMap<Value *, MemoryAccess *> PtrToAcc;
DenseSet<Value *> HasWriteAccess;
for (ScopStmt &Stmt : *this) {
// Skip statements with an empty domain as they will never be executed.
isl_set *StmtDomain = Stmt.getDomain();
bool StmtDomainEmpty = isl_set_is_empty(StmtDomain);
isl_set_free(StmtDomain);
if (StmtDomainEmpty)
continue;
for (MemoryAccess *MA : Stmt) {
if (MA->isScalarKind())
continue;
if (!MA->isRead())
HasWriteAccess.insert(MA->getBaseAddr());
MemAccInst Acc(MA->getAccessInstruction());
if (MA->isRead() && isa<MemTransferInst>(Acc))
PtrToAcc[cast<MemTransferInst>(Acc)->getSource()] = MA;
else
PtrToAcc[Acc.getPointerOperand()] = 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()]);
if (AG.size() < 2)
continue;
AliasGroups.push_back(std::move(AG));
}
// Split the alias groups based on their domain.
for (unsigned u = 0; u < AliasGroups.size(); u++) {
AliasGroupTy NewAG;
AliasGroupTy &AG = AliasGroups[u];
AliasGroupTy::iterator AGI = AG.begin();
isl_set *AGDomain = getAccessDomain(*AGI);
while (AGI != AG.end()) {
MemoryAccess *MA = *AGI;
isl_set *MADomain = getAccessDomain(MA);
if (isl_set_is_disjoint(AGDomain, MADomain)) {
NewAG.push_back(MA);
AGI = AG.erase(AGI);
isl_set_free(MADomain);
} else {
AGDomain = isl_set_union(AGDomain, MADomain);
AGI++;
}
}
if (NewAG.size() > 1)
AliasGroups.push_back(std::move(NewAG));
isl_set_free(AGDomain);
}
auto &F = getFunction();
MapVector<const Value *, SmallPtrSet<MemoryAccess *, 8>> ReadOnlyPairs;
SmallPtrSet<const Value *, 4> NonReadOnlyBaseValues;
for (AliasGroupTy &AG : AliasGroups) {
NonReadOnlyBaseValues.clear();
ReadOnlyPairs.clear();
if (AG.size() < 2) {
AG.clear();
continue;
}
for (auto II = AG.begin(); II != AG.end();) {
emitOptimizationRemarkAnalysis(
F.getContext(), DEBUG_TYPE, F,
(*II)->getAccessInstruction()->getDebugLoc(),
"Possibly aliasing pointer, use restrict keyword.");
Value *BaseAddr = (*II)->getBaseAddr();
if (HasWriteAccess.count(BaseAddr)) {
NonReadOnlyBaseValues.insert(BaseAddr);
II++;
} else {
ReadOnlyPairs[BaseAddr].insert(*II);
II = AG.erase(II);
}
}
// If we don't have read only pointers check if there are at least two
// non read only pointers, otherwise clear the alias group.
if (ReadOnlyPairs.empty() && NonReadOnlyBaseValues.size() <= 1) {
AG.clear();
continue;
}
// If we don't have non read only pointers clear the alias group.
if (NonReadOnlyBaseValues.empty()) {
AG.clear();
continue;
}
// Check if we have non-affine accesses left, if so bail out as we cannot
// generate a good access range yet.
for (auto *MA : AG) {
if (!MA->isAffine()) {
invalidate(ALIASING, MA->getAccessInstruction()->getDebugLoc());
return false;
}
if (auto *BasePtrMA = lookupBasePtrAccess(MA))
addRequiredInvariantLoad(
cast<LoadInst>(BasePtrMA->getAccessInstruction()));
}
for (auto &ReadOnlyPair : ReadOnlyPairs)
for (auto *MA : ReadOnlyPair.second) {
if (!MA->isAffine()) {
invalidate(ALIASING, MA->getAccessInstruction()->getDebugLoc());
return false;
}
if (auto *BasePtrMA = lookupBasePtrAccess(MA))
addRequiredInvariantLoad(
cast<LoadInst>(BasePtrMA->getAccessInstruction()));
}
// 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.size() >
RunTimeChecksMaxArraysPerGroup))
return false;
// Calculate minimal and maximal accesses for read only accesses.
MinMaxAccessesReadOnly.reserve(ReadOnlyPairs.size());
Accesses = isl_union_map_empty(getParamSpace());
for (const auto &ReadOnlyPair : ReadOnlyPairs)
for (MemoryAccess *MA : ReadOnlyPair.second)
Accesses = isl_union_map_add_map(Accesses, MA->getAccessRelation());
Valid =
calculateMinMaxAccess(Accesses, getDomains(), MinMaxAccessesReadOnly);
if (!Valid)
return false;
}
return true;
}
/// @brief Get the smallest loop that contains @p S but is not in @p S.
static Loop *getLoopSurroundingScop(Scop &S, LoopInfo &LI) {
// Start with the smallest loop containing the entry and expand that
// loop until it contains all blocks in the region. If there is a loop
// containing all blocks in the region check if it is itself contained
// and if so take the parent loop as it will be the smallest containing
// the region but not contained by it.
Loop *L = LI.getLoopFor(S.getEntry());
while (L) {
bool AllContained = true;
for (auto *BB : S.blocks())
AllContained &= L->contains(BB);
if (AllContained)
break;
L = L->getParentLoop();
}
return L ? (S.contains(L) ? L->getParentLoop() : L) : nullptr;
}
Scop::Scop(Region &R, ScalarEvolution &ScalarEvolution, LoopInfo &LI,
ScopDetection::DetectionContext &DC)
: SE(&ScalarEvolution), R(R), IsOptimized(false),
HasSingleExitEdge(R.getExitingBlock()), HasErrorBlock(false),
MaxLoopDepth(0), DC(DC), IslCtx(isl_ctx_alloc(), isl_ctx_free),
Context(nullptr), Affinator(this, LI), AssumedContext(nullptr),
InvalidContext(nullptr), Schedule(nullptr) {
if (IslOnErrorAbort)
isl_options_set_on_error(getIslCtx(), ISL_ON_ERROR_ABORT);
buildContext();
}
void Scop::init(AliasAnalysis &AA, AssumptionCache &AC, DominatorTree &DT,
LoopInfo &LI) {
buildInvariantEquivalenceClasses();
if (!buildDomains(&R, DT, LI))
return;
addUserAssumptions(AC, DT, LI);
// Remove empty statements.
// Exit early in case there are no executable statements left in this scop.
simplifySCoP(false, DT, LI);
if (Stmts.empty())
return;
// The ScopStmts now have enough information to initialize themselves.
for (ScopStmt &Stmt : Stmts)
Stmt.init(LI);
// Check early for profitability. Afterwards it cannot change anymore,
// only the runtime context could become infeasible.
if (!isProfitable()) {
invalidate(PROFITABLE, DebugLoc());
return;
}
buildSchedule(LI);
updateAccessDimensionality();
realignParams();
addUserContext();
// After the context was fully constructed, thus all our knowledge about
// the parameters is in there, we add all recorded assumptions to the
// assumed/invalid context.
addRecordedAssumptions();
simplifyContexts();
if (!buildAliasChecks(AA))
return;
hoistInvariantLoads();
verifyInvariantLoads();
simplifySCoP(true, DT, LI);
// Check late for a feasible runtime context because profitability did not
// change.
if (!hasFeasibleRuntimeContext()) {
invalidate(PROFITABLE, DebugLoc());
return;
}
}
Scop::~Scop() {
isl_set_free(Context);
isl_set_free(AssumedContext);
isl_set_free(InvalidContext);
isl_schedule_free(Schedule);
for (auto &It : ParameterIds)
isl_id_free(It.second);
for (auto It : DomainMap)
isl_set_free(It.second);
for (auto &AS : RecordedAssumptions)
isl_set_free(AS.Set);
// Free the alias groups
for (MinMaxVectorPairTy &MinMaxAccessPair : MinMaxAliasGroups) {
for (MinMaxAccessTy &MMA : MinMaxAccessPair.first) {
isl_pw_multi_aff_free(MMA.first);
isl_pw_multi_aff_free(MMA.second);
}
for (MinMaxAccessTy &MMA : MinMaxAccessPair.second) {
isl_pw_multi_aff_free(MMA.first);
isl_pw_multi_aff_free(MMA.second);
}
}
for (const auto &IAClass : InvariantEquivClasses)
isl_set_free(std::get<2>(IAClass));
// Explicitly release all Scop objects and the underlying isl objects before
// we relase the isl context.
Stmts.clear();
ScopArrayInfoMap.clear();
AccFuncMap.clear();
}
void Scop::updateAccessDimensionality() {
// Check all array accesses for each base pointer and find a (virtual) element
// size for the base pointer that divides all access functions.
for (auto &Stmt : *this)
for (auto *Access : Stmt) {
if (!Access->isArrayKind())
continue;
auto &SAI = ScopArrayInfoMap[std::make_pair(Access->getBaseAddr(),
ScopArrayInfo::MK_Array)];
if (SAI->getNumberOfDimensions() != 1)
continue;
unsigned DivisibleSize = SAI->getElemSizeInBytes();
auto *Subscript = Access->getSubscript(0);
while (!isDivisible(Subscript, DivisibleSize, *SE))
DivisibleSize /= 2;
auto *Ty = IntegerType::get(SE->getContext(), DivisibleSize * 8);
SAI->updateElementType(Ty);
}
for (auto &Stmt : *this)
for (auto &Access : Stmt)
Access->updateDimensionality();
}
void Scop::simplifySCoP(bool AfterHoisting, DominatorTree &DT, LoopInfo &LI) {
for (auto StmtIt = Stmts.begin(), StmtEnd = Stmts.end(); StmtIt != StmtEnd;) {
ScopStmt &Stmt = *StmtIt;
bool RemoveStmt = Stmt.isEmpty();
if (!RemoveStmt)
RemoveStmt = !DomainMap[Stmt.getEntryBlock()];
// Remove read only statements only after invariant loop hoisting.
if (!RemoveStmt && AfterHoisting) {
bool OnlyRead = true;
for (MemoryAccess *MA : Stmt) {
if (MA->isRead())
continue;
OnlyRead = false;
break;
}
RemoveStmt = OnlyRead;
}
if (!RemoveStmt) {
StmtIt++;
continue;
}
// Remove the statement because it is unnecessary.
if (Stmt.isRegionStmt())
for (BasicBlock *BB : Stmt.getRegion()->blocks())
StmtMap.erase(BB);
else
StmtMap.erase(Stmt.getBasicBlock());
StmtIt = Stmts.erase(StmtIt);
}
}
InvariantEquivClassTy *Scop::lookupInvariantEquivClass(Value *Val) {
LoadInst *LInst = dyn_cast<LoadInst>(Val);
if (!LInst)
return nullptr;
if (Value *Rep = InvEquivClassVMap.lookup(LInst))
LInst = cast<LoadInst>(Rep);
Type *Ty = LInst->getType();
const SCEV *PointerSCEV = SE->getSCEV(LInst->getPointerOperand());
for (auto &IAClass : InvariantEquivClasses) {
if (PointerSCEV != std::get<0>(IAClass) || Ty != std::get<3>(IAClass))
continue;
auto &MAs = std::get<1>(IAClass);
for (auto *MA : MAs)
if (MA->getAccessInstruction() == Val)
return &IAClass;
}
return nullptr;
}
/// @brief Check if @p MA can always be hoisted without execution context.
static bool canAlwaysBeHoisted(MemoryAccess *MA, bool StmtInvalidCtxIsEmpty,
bool MAInvalidCtxIsEmpty,
bool NonHoistableCtxIsEmpty) {
LoadInst *LInst = cast<LoadInst>(MA->getAccessInstruction());
const DataLayout &DL = LInst->getParent()->getModule()->getDataLayout();
// TODO: We can provide more information for better but more expensive
// results.
if (!isDereferenceableAndAlignedPointer(LInst->getPointerOperand(),
LInst->getAlignment(), DL))
return false;
// If the location might be overwritten we do not hoist it unconditionally.
//
// TODO: This is probably to conservative.
if (!NonHoistableCtxIsEmpty)
return false;
// If a dereferencable load is in a statement that is modeled precisely we can
// hoist it.
if (StmtInvalidCtxIsEmpty && MAInvalidCtxIsEmpty)
return true;
// Even if the statement is not modeled precisely we can hoist the load if it
// does not involve any parameters that might have been specilized by the
// statement domain.
for (unsigned u = 0, e = MA->getNumSubscripts(); u < e; u++)
if (!isa<SCEVConstant>(MA->getSubscript(u)))
return false;
return true;
}
void Scop::addInvariantLoads(ScopStmt &Stmt, InvariantAccessesTy &InvMAs) {
if (InvMAs.empty())
return;
auto *StmtInvalidCtx = Stmt.getInvalidContext();
bool StmtInvalidCtxIsEmpty = isl_set_is_empty(StmtInvalidCtx);
// Get the context under which the statement is executed but remove the error
// context under which this statement is reached.
isl_set *DomainCtx = isl_set_params(Stmt.getDomain());
DomainCtx = isl_set_subtract(DomainCtx, StmtInvalidCtx);
if (isl_set_n_basic_set(DomainCtx) >= MaxDisjunctionsInDomain) {
auto *AccInst = InvMAs.front().MA->getAccessInstruction();
invalidate(COMPLEXITY, AccInst->getDebugLoc());
isl_set_free(DomainCtx);
for (auto &InvMA : InvMAs)
isl_set_free(InvMA.NonHoistableCtx);
return;
}
// Project out all parameters that relate to loads in the statement. Otherwise
// we could have cyclic dependences on the constraints under which the
// hoisted loads are executed and we could not determine an order in which to
// pre-load them. This happens because not only lower bounds are part of the
// domain but also upper bounds.
for (auto &InvMA : InvMAs) {
auto *MA = InvMA.MA;
Instruction *AccInst = MA->getAccessInstruction();
if (SE->isSCEVable(AccInst->getType())) {
SetVector<Value *> Values;
for (const SCEV *Parameter : Parameters) {
Values.clear();
findValues(Parameter, *SE, Values);
if (!Values.count(AccInst))
continue;
if (isl_id *ParamId = getIdForParam(Parameter)) {
int Dim = isl_set_find_dim_by_id(DomainCtx, isl_dim_param, ParamId);
DomainCtx = isl_set_eliminate(DomainCtx, isl_dim_param, Dim, 1);
isl_id_free(ParamId);
}
}
}
}
for (auto &InvMA : InvMAs) {
auto *MA = InvMA.MA;
auto *NHCtx = InvMA.NonHoistableCtx;
// Check for another invariant access that accesses the same location as
// MA and if found consolidate them. Otherwise create a new equivalence
// class at the end of InvariantEquivClasses.
LoadInst *LInst = cast<LoadInst>(MA->getAccessInstruction());
Type *Ty = LInst->getType();
const SCEV *PointerSCEV = SE->getSCEV(LInst->getPointerOperand());
auto *MAInvalidCtx = MA->getInvalidContext();
bool NonHoistableCtxIsEmpty = isl_set_is_empty(NHCtx);
bool MAInvalidCtxIsEmpty = isl_set_is_empty(MAInvalidCtx);
isl_set *MACtx;
// Check if we know that this pointer can be speculatively accessed.
if (canAlwaysBeHoisted(MA, StmtInvalidCtxIsEmpty, MAInvalidCtxIsEmpty,
NonHoistableCtxIsEmpty)) {
MACtx = isl_set_universe(isl_set_get_space(DomainCtx));
isl_set_free(MAInvalidCtx);
isl_set_free(NHCtx);
} else {
MACtx = isl_set_copy(DomainCtx);
MACtx = isl_set_subtract(MACtx, isl_set_union(MAInvalidCtx, NHCtx));
MACtx = isl_set_gist_params(MACtx, getContext());
}
bool Consolidated = false;
for (auto &IAClass : InvariantEquivClasses) {
if (PointerSCEV != std::get<0>(IAClass) || Ty != std::get<3>(IAClass))
continue;
// If the pointer and the type is equal check if the access function wrt.
// to the domain is equal too. It can happen that the domain fixes
// parameter values and these can be different for distinct part of the
// SCoP. If this happens we cannot consolidate the loads but need to
// create a new invariant load equivalence class.
auto &MAs = std::get<1>(IAClass);
if (!MAs.empty()) {
auto *LastMA = MAs.front();
auto *AR = isl_map_range(MA->getAccessRelation());
auto *LastAR = isl_map_range(LastMA->getAccessRelation());
bool SameAR = isl_set_is_equal(AR, LastAR);
isl_set_free(AR);
isl_set_free(LastAR);
if (!SameAR)
continue;
}
// Add MA to the list of accesses that are in this class.
MAs.push_front(MA);
Consolidated = true;
// Unify the execution context of the class and this statement.
isl_set *&IAClassDomainCtx = std::get<2>(IAClass);
if (IAClassDomainCtx)
IAClassDomainCtx =
isl_set_coalesce(isl_set_union(IAClassDomainCtx, MACtx));
else
IAClassDomainCtx = MACtx;
break;
}
if (Consolidated)
continue;
// If we did not consolidate MA, thus did not find an equivalence class
// for it, we create a new one.
InvariantEquivClasses.emplace_back(PointerSCEV, MemoryAccessList{MA}, MACtx,
Ty);
}
isl_set_free(DomainCtx);
}
__isl_give isl_set *Scop::getNonHoistableCtx(MemoryAccess *Access,
__isl_keep isl_union_map *Writes) {
// TODO: Loads that are not loop carried, hence are in a statement with
// zero iterators, are by construction invariant, though we
// currently "hoist" them anyway. This is necessary because we allow
// them to be treated as parameters (e.g., in conditions) and our code
// generation would otherwise use the old value.
auto &Stmt = *Access->getStatement();
BasicBlock *BB = Stmt.getEntryBlock();
if (Access->isScalarKind() || Access->isWrite() || !Access->isAffine())
return nullptr;
// Skip accesses that have an invariant base pointer which is defined but
// not loaded inside the SCoP. This can happened e.g., if a readnone call
// returns a pointer that is used as a base address. However, as we want
// to hoist indirect pointers, we allow the base pointer to be defined in
// the region if it is also a memory access. Each ScopArrayInfo object
// that has a base pointer origin has a base pointer that is loaded and
// that it is invariant, thus it will be hoisted too. However, if there is
// no base pointer origin we check that the base pointer is defined
// outside the region.
auto *LI = cast<LoadInst>(Access->getAccessInstruction());
if (hasNonHoistableBasePtrInScop(Access, Writes))
return nullptr;
// Skip accesses in non-affine subregions as they might not be executed
// under the same condition as the entry of the non-affine subregion.
if (BB != LI->getParent())
return nullptr;
isl_map *AccessRelation = Access->getAccessRelation();
assert(!isl_map_is_empty(AccessRelation));
if (isl_map_involves_dims(AccessRelation, isl_dim_in, 0,
Stmt.getNumIterators())) {
isl_map_free(AccessRelation);
return nullptr;
}
AccessRelation = isl_map_intersect_domain(AccessRelation, Stmt.getDomain());
isl_set *AccessRange = isl_map_range(AccessRelation);
isl_union_map *Written = isl_union_map_intersect_range(
isl_union_map_copy(Writes), isl_union_set_from_set(AccessRange));
auto *WrittenCtx = isl_union_map_params(Written);
bool IsWritten = !isl_set_is_empty(WrittenCtx);
if (!IsWritten)
return WrittenCtx;
WrittenCtx = isl_set_remove_divs(WrittenCtx);
bool TooComplex = isl_set_n_basic_set(WrittenCtx) >= MaxDisjunctionsInDomain;
if (TooComplex || !isRequiredInvariantLoad(LI)) {
isl_set_free(WrittenCtx);
return nullptr;
}
addAssumption(INVARIANTLOAD, isl_set_copy(WrittenCtx), LI->getDebugLoc(),
AS_RESTRICTION);
return WrittenCtx;
}
void Scop::verifyInvariantLoads() {
auto &RIL = getRequiredInvariantLoads();
for (LoadInst *LI : RIL) {
assert(LI && contains(LI));
ScopStmt *Stmt = getStmtFor(LI);
if (Stmt && Stmt->getArrayAccessOrNULLFor(LI)) {
invalidate(INVARIANTLOAD, LI->getDebugLoc());
return;
}
}
}
void Scop::hoistInvariantLoads() {
if (!PollyInvariantLoadHoisting)
return;
isl_union_map *Writes = getWrites();
for (ScopStmt &Stmt : *this) {
InvariantAccessesTy InvariantAccesses;
for (MemoryAccess *Access : Stmt)
if (auto *NHCtx = getNonHoistableCtx(Access, Writes))
InvariantAccesses.push_back({Access, NHCtx});
// Transfer the memory access from the statement to the SCoP.
for (auto InvMA : InvariantAccesses)
Stmt.removeMemoryAccess(InvMA.MA);
addInvariantLoads(Stmt, InvariantAccesses);
}
isl_union_map_free(Writes);
}
const ScopArrayInfo *
Scop::getOrCreateScopArrayInfo(Value *BasePtr, Type *ElementType,
ArrayRef<const SCEV *> Sizes,
ScopArrayInfo::MemoryKind Kind) {
auto &SAI = ScopArrayInfoMap[std::make_pair(BasePtr, Kind)];
if (!SAI) {
auto &DL = getFunction().getParent()->getDataLayout();
SAI.reset(new ScopArrayInfo(BasePtr, ElementType, getIslCtx(), Sizes, Kind,
DL, this));
} else {
SAI->updateElementType(ElementType);
// In case of mismatching array sizes, we bail out by setting the run-time
// context to false.
if (!SAI->updateSizes(Sizes))
invalidate(DELINEARIZATION, DebugLoc());
}
return SAI.get();
}
const ScopArrayInfo *Scop::getScopArrayInfo(Value *BasePtr,
ScopArrayInfo::MemoryKind Kind) {
auto *SAI = ScopArrayInfoMap[std::make_pair(BasePtr, Kind)].get();
assert(SAI && "No ScopArrayInfo available for this base pointer");
return SAI;
}
std::string Scop::getContextStr() const { return stringFromIslObj(Context); }
std::string Scop::getAssumedContextStr() const {
assert(AssumedContext && "Assumed context not yet built");
return stringFromIslObj(AssumedContext);
}
std::string Scop::getInvalidContextStr() const {
return stringFromIslObj(InvalidContext);
}
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 {
assert(AssumedContext && "Assumed context not yet built");
return isl_set_copy(AssumedContext);
}
bool Scop::isProfitable() const {
if (PollyProcessUnprofitable)
return true;
if (!hasFeasibleRuntimeContext())
return false;
if (isEmpty())
return false;
unsigned OptimizableStmtsOrLoops = 0;
for (auto &Stmt : *this) {
if (Stmt.getNumIterators() == 0)
continue;
bool ContainsArrayAccs = false;
bool ContainsScalarAccs = false;
for (auto *MA : Stmt) {
if (MA->isRead())
continue;
ContainsArrayAccs |= MA->isArrayKind();
ContainsScalarAccs |= MA->isScalarKind();
}
if (ContainsArrayAccs && !ContainsScalarAccs)
OptimizableStmtsOrLoops += Stmt.getNumIterators();
}
return OptimizableStmtsOrLoops > 1;
}
bool Scop::hasFeasibleRuntimeContext() const {
auto *PositiveContext = getAssumedContext();
auto *NegativeContext = getInvalidContext();
PositiveContext = addNonEmptyDomainConstraints(PositiveContext);
bool IsFeasible = !(isl_set_is_empty(PositiveContext) ||
isl_set_is_subset(PositiveContext, NegativeContext));
isl_set_free(PositiveContext);
if (!IsFeasible) {
isl_set_free(NegativeContext);
return false;
}
auto *DomainContext = isl_union_set_params(getDomains());
IsFeasible = !isl_set_is_subset(DomainContext, NegativeContext);
IsFeasible &= !isl_set_is_subset(Context, NegativeContext);
isl_set_free(NegativeContext);
isl_set_free(DomainContext);
return IsFeasible;
}
static std::string toString(AssumptionKind Kind) {
switch (Kind) {
case ALIASING:
return "No-aliasing";
case INBOUNDS:
return "Inbounds";
case WRAPPING:
return "No-overflows";
case UNSIGNED:
return "Signed-unsigned";
case COMPLEXITY:
return "Low complexity";
case PROFITABLE:
return "Profitable";
case ERRORBLOCK:
return "No-error";
case INFINITELOOP:
return "Finite loop";
case INVARIANTLOAD:
return "Invariant load";
case DELINEARIZATION:
return "Delinearization";
}
llvm_unreachable("Unknown AssumptionKind!");
}
bool Scop::isEffectiveAssumption(__isl_keep isl_set *Set, AssumptionSign Sign) {
if (Sign == AS_ASSUMPTION) {
if (isl_set_is_subset(Context, Set))
return false;
if (isl_set_is_subset(AssumedContext, Set))
return false;
} else {
if (isl_set_is_disjoint(Set, Context))
return false;
if (isl_set_is_subset(Set, InvalidContext))
return false;
}
return true;
}
bool Scop::trackAssumption(AssumptionKind Kind, __isl_keep isl_set *Set,
DebugLoc Loc, AssumptionSign Sign) {
if (PollyRemarksMinimal && !isEffectiveAssumption(Set, Sign))
return false;
auto &F = getFunction();
auto Suffix = Sign == AS_ASSUMPTION ? " assumption:\t" : " restriction:\t";
std::string Msg = toString(Kind) + Suffix + stringFromIslObj(Set);
emitOptimizationRemarkAnalysis(F.getContext(), DEBUG_TYPE, F, Loc, Msg);
return true;
}
void Scop::addAssumption(AssumptionKind Kind, __isl_take isl_set *Set,
DebugLoc Loc, AssumptionSign Sign) {
// Simplify the assumptions/restrictions first.
Set = isl_set_gist_params(Set, getContext());
if (!trackAssumption(Kind, Set, Loc, Sign)) {
isl_set_free(Set);
return;
}
if (Sign == AS_ASSUMPTION) {
AssumedContext = isl_set_intersect(AssumedContext, Set);
AssumedContext = isl_set_coalesce(AssumedContext);
} else {
InvalidContext = isl_set_union(InvalidContext, Set);
InvalidContext = isl_set_coalesce(InvalidContext);
}
}
void Scop::recordAssumption(AssumptionKind Kind, __isl_take isl_set *Set,
DebugLoc Loc, AssumptionSign Sign, BasicBlock *BB) {
RecordedAssumptions.push_back({Kind, Sign, Set, Loc, BB});
}
void Scop::addRecordedAssumptions() {
while (!RecordedAssumptions.empty()) {
const Assumption &AS = RecordedAssumptions.pop_back_val();
if (!AS.BB) {
addAssumption(AS.Kind, AS.Set, AS.Loc, AS.Sign);
continue;
}
// If the domain was deleted the assumptions are void.
isl_set *Dom = getDomainConditions(AS.BB);
if (!Dom) {
isl_set_free(AS.Set);
continue;
}
// If a basic block was given use its domain to simplify the assumption.
// In case of restrictions we know they only have to hold on the domain,
// thus we can intersect them with the domain of the block. However, for
// assumptions the domain has to imply them, thus:
// _ _____
// Dom => S <==> A v B <==> A - B
//
// To avoid the complement we will register A - B as a restricton not an
// assumption.
isl_set *S = AS.Set;
if (AS.Sign == AS_RESTRICTION)
S = isl_set_params(isl_set_intersect(S, Dom));
else /* (AS.Sign == AS_ASSUMPTION) */
S = isl_set_params(isl_set_subtract(Dom, S));
addAssumption(AS.Kind, S, AS.Loc, AS_RESTRICTION);
}
}
void Scop::invalidate(AssumptionKind Kind, DebugLoc Loc) {
addAssumption(Kind, isl_set_empty(getParamSpace()), Loc, AS_ASSUMPTION);
}
__isl_give isl_set *Scop::getInvalidContext() const {
return isl_set_copy(InvalidContext);
}
void Scop::printContext(raw_ostream &OS) const {
OS << "Context:\n";
OS.indent(4) << Context << "\n";
OS.indent(4) << "Assumed Context:\n";
OS.indent(4) << AssumedContext << "\n";
OS.indent(4) << "Invalid Context:\n";
OS.indent(4) << InvalidContext << "\n";
unsigned Dim = 0;
for (const SCEV *Parameter : Parameters)
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: " << getFunction().getName() << "\n";
OS.indent(4) << "Region: " << getNameStr() << "\n";
OS.indent(4) << "Max Loop Depth: " << getMaxLoopDepth() << "\n";
OS.indent(4) << "Invariant Accesses: {\n";
for (const auto &IAClass : InvariantEquivClasses) {
const auto &MAs = std::get<1>(IAClass);
if (MAs.empty()) {
OS.indent(12) << "Class Pointer: " << *std::get<0>(IAClass) << "\n";
} else {
MAs.front()->print(OS);
OS.indent(12) << "Execution Context: " << std::get<2>(IAClass) << "\n";
}
}
OS.indent(4) << "}\n";
printContext(OS.indent(4));
printArrayInfo(OS.indent(4));
printAliasAssumptions(OS);
printStatements(OS.indent(4));
}
void Scop::dump() const { print(dbgs()); }
isl_ctx *Scop::getIslCtx() const { return IslCtx.get(); }
__isl_give PWACtx Scop::getPwAff(const SCEV *E, BasicBlock *BB,
bool NonNegative) {
// First try to use the SCEVAffinator to generate a piecewise defined
// affine function from @p E in the context of @p BB. If that tasks becomes to
// complex the affinator might return a nullptr. In such a case we invalidate
// the SCoP and return a dummy value. This way we do not need to add error
// handling cdoe to all users of this function.
auto PWAC = Affinator.getPwAff(E, BB);
if (PWAC.first) {
// TODO: We could use a heuristic and either use:
// SCEVAffinator::takeNonNegativeAssumption
// or
// SCEVAffinator::interpretAsUnsigned
// to deal with unsigned or "NonNegative" SCEVs.
if (NonNegative)
Affinator.takeNonNegativeAssumption(PWAC);
return PWAC;
}
auto DL = BB ? BB->getTerminator()->getDebugLoc() : DebugLoc();
invalidate(COMPLEXITY, DL);
return Affinator.getPwAff(SE->getZero(E->getType()), 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_pw_aff *Scop::getPwAffOnly(const SCEV *E, BasicBlock *BB) {
PWACtx PWAC = getPwAff(E, BB);
isl_set_free(PWAC.second);
return PWAC.first;
}
__isl_give isl_union_map *
Scop::getAccessesOfType(std::function<bool(MemoryAccess &)> Predicate) {
isl_union_map *Accesses = isl_union_map_empty(getParamSpace());
for (ScopStmt &Stmt : *this) {
for (MemoryAccess *MA : Stmt) {
if (!Predicate(*MA))
continue;
isl_set *Domain = Stmt.getDomain();
isl_map *AccessDomain = MA->getAccessRelation();
AccessDomain = isl_map_intersect_domain(AccessDomain, Domain);
Accesses = isl_union_map_add_map(Accesses, AccessDomain);
}
}
return isl_union_map_coalesce(Accesses);
}
__isl_give isl_union_map *Scop::getMustWrites() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isMustWrite(); });
}
__isl_give isl_union_map *Scop::getMayWrites() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isMayWrite(); });
}
__isl_give isl_union_map *Scop::getWrites() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isWrite(); });
}
__isl_give isl_union_map *Scop::getReads() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isRead(); });
}
__isl_give isl_union_map *Scop::getAccesses() {
return getAccessesOfType([](MemoryAccess &MA) { return true; });
}
__isl_give isl_union_map *Scop::getSchedule() const {
auto *Tree = getScheduleTree();
auto *S = isl_schedule_get_map(Tree);
isl_schedule_free(Tree);
return S;
}
__isl_give isl_schedule *Scop::getScheduleTree() const {
return isl_schedule_intersect_domain(isl_schedule_copy(Schedule),
getDomains());
}
void Scop::setSchedule(__isl_take isl_union_map *NewSchedule) {
auto *S = isl_schedule_from_domain(getDomains());
S = isl_schedule_insert_partial_schedule(
S, isl_multi_union_pw_aff_from_union_map(NewSchedule));
isl_schedule_free(Schedule);
Schedule = S;
}
void Scop::setScheduleTree(__isl_take isl_schedule *NewSchedule) {
isl_schedule_free(Schedule);
Schedule = NewSchedule;
}
bool Scop::restrictDomains(__isl_take isl_union_set *Domain) {
bool Changed = false;
for (ScopStmt &Stmt : *this) {
isl_union_set *StmtDomain = isl_union_set_from_set(Stmt.getDomain());
isl_union_set *NewStmtDomain = isl_union_set_intersect(
isl_union_set_copy(StmtDomain), isl_union_set_copy(Domain));
if (isl_union_set_is_subset(StmtDomain, NewStmtDomain)) {
isl_union_set_free(StmtDomain);
isl_union_set_free(NewStmtDomain);
continue;
}
Changed = true;
isl_union_set_free(StmtDomain);
NewStmtDomain = isl_union_set_coalesce(NewStmtDomain);
if (isl_union_set_is_empty(NewStmtDomain)) {
Stmt.restrictDomain(isl_set_empty(Stmt.getDomainSpace()));
isl_union_set_free(NewStmtDomain);
} else
Stmt.restrictDomain(isl_set_from_union_set(NewStmtDomain));
}
isl_union_set_free(Domain);
return Changed;
}
ScalarEvolution *Scop::getSE() const { return SE; }
struct MapToDimensionDataTy {
int N;
isl_union_pw_multi_aff *Res;
};
// @brief Create a function that maps the elements of 'Set' to its N-th
// dimension and add it to User->Res.
//
// @param Set The input set.
// @param User->N The dimension to map to.
// @param User->Res The isl_union_pw_multi_aff to which to add the result.
//
// @returns isl_stat_ok if no error occured, othewise isl_stat_error.
static isl_stat mapToDimension_AddSet(__isl_take isl_set *Set, void *User) {
struct MapToDimensionDataTy *Data = (struct MapToDimensionDataTy *)User;
int Dim;
isl_space *Space;
isl_pw_multi_aff *PMA;
Dim = isl_set_dim(Set, isl_dim_set);
Space = isl_set_get_space(Set);
PMA = isl_pw_multi_aff_project_out_map(Space, isl_dim_set, Data->N,
Dim - Data->N);
if (Data->N > 1)
PMA = isl_pw_multi_aff_drop_dims(PMA, isl_dim_out, 0, Data->N - 1);
Data->Res = isl_union_pw_multi_aff_add_pw_multi_aff(Data->Res, PMA);
isl_set_free(Set);
return isl_stat_ok;
}
// @brief Create an isl_multi_union_aff that defines an identity mapping
// from the elements of USet to their N-th dimension.
//
// # Example:
//
// Domain: { A[i,j]; B[i,j,k] }
// N: 1
//
// Resulting Mapping: { {A[i,j] -> [(j)]; B[i,j,k] -> [(j)] }
//
// @param USet A union set describing the elements for which to generate a
// mapping.
// @param N The dimension to map to.
// @returns A mapping from USet to its N-th dimension.
static __isl_give isl_multi_union_pw_aff *
mapToDimension(__isl_take isl_union_set *USet, int N) {
assert(N >= 0);
assert(USet);
assert(!isl_union_set_is_empty(USet));
struct MapToDimensionDataTy Data;
auto *Space = isl_union_set_get_space(USet);
auto *PwAff = isl_union_pw_multi_aff_empty(Space);
Data = {N, PwAff};
auto Res = isl_union_set_foreach_set(USet, &mapToDimension_AddSet, &Data);
(void)Res;
assert(Res == isl_stat_ok);
isl_union_set_free(USet);
return isl_multi_union_pw_aff_from_union_pw_multi_aff(Data.Res);
}
void Scop::addScopStmt(BasicBlock *BB, Region *R) {
if (BB) {
Stmts.emplace_back(*this, *BB);
auto *Stmt = &Stmts.back();
StmtMap[BB] = Stmt;
} else {
assert(R && "Either basic block or a region expected.");
Stmts.emplace_back(*this, *R);
auto *Stmt = &Stmts.back();
for (BasicBlock *BB : R->blocks())
StmtMap[BB] = Stmt;
}
}
void Scop::buildSchedule(LoopInfo &LI) {
Loop *L = getLoopSurroundingScop(*this, LI);
LoopStackTy LoopStack({LoopStackElementTy(L, nullptr, 0)});
buildSchedule(getRegion().getNode(), LoopStack, LI);
assert(LoopStack.size() == 1 && LoopStack.back().L == L);
Schedule = LoopStack[0].Schedule;
}
/// To generate a schedule for the elements in a Region we traverse the Region
/// in reverse-post-order and add the contained RegionNodes in traversal order
/// to the schedule of the loop that is currently at the top of the LoopStack.
/// For loop-free codes, this results in a correct sequential ordering.
///
/// Example:
/// bb1(0)
/// / \.
/// bb2(1) bb3(2)
/// \ / \.
/// bb4(3) bb5(4)
/// \ /
/// bb6(5)
///
/// Including loops requires additional processing. Whenever a loop header is
/// encountered, the corresponding loop is added to the @p LoopStack. Starting
/// from an empty schedule, we first process all RegionNodes that are within
/// this loop and complete the sequential schedule at this loop-level before
/// processing about any other nodes. To implement this
/// loop-nodes-first-processing, the reverse post-order traversal is
/// insufficient. Hence, we additionally check if the traversal yields
/// sub-regions or blocks that are outside the last loop on the @p LoopStack.
/// These region-nodes are then queue and only traverse after the all nodes
/// within the current loop have been processed.
void Scop::buildSchedule(Region *R, LoopStackTy &LoopStack, LoopInfo &LI) {
Loop *OuterScopLoop = getLoopSurroundingScop(*this, LI);
ReversePostOrderTraversal<Region *> RTraversal(R);
std::deque<RegionNode *> WorkList(RTraversal.begin(), RTraversal.end());
std::deque<RegionNode *> DelayList;
bool LastRNWaiting = false;
// Iterate over the region @p R in reverse post-order but queue
// sub-regions/blocks iff they are not part of the last encountered but not
// completely traversed loop. The variable LastRNWaiting is a flag to indicate
// that we queued the last sub-region/block from the reverse post-order
// iterator. If it is set we have to explore the next sub-region/block from
// the iterator (if any) to guarantee progress. If it is not set we first try
// the next queued sub-region/blocks.
while (!WorkList.empty() || !DelayList.empty()) {
RegionNode *RN;
if ((LastRNWaiting && !WorkList.empty()) || DelayList.size() == 0) {
RN = WorkList.front();
WorkList.pop_front();
LastRNWaiting = false;
} else {
RN = DelayList.front();
DelayList.pop_front();
}
Loop *L = getRegionNodeLoop(RN, LI);
if (!contains(L))
L = OuterScopLoop;
Loop *LastLoop = LoopStack.back().L;
if (LastLoop != L) {
if (LastLoop && !LastLoop->contains(L)) {
LastRNWaiting = true;
DelayList.push_back(RN);
continue;
}
LoopStack.push_back({L, nullptr, 0});
}
buildSchedule(RN, LoopStack, LI);
}
return;
}
void Scop::buildSchedule(RegionNode *RN, LoopStackTy &LoopStack, LoopInfo &LI) {
if (RN->isSubRegion()) {
auto *LocalRegion = RN->getNodeAs<Region>();
if (!isNonAffineSubRegion(LocalRegion)) {
buildSchedule(LocalRegion, LoopStack, LI);
return;
}
}
auto &LoopData = LoopStack.back();
LoopData.NumBlocksProcessed += getNumBlocksInRegionNode(RN);
if (auto *Stmt = getStmtFor(RN)) {
auto *UDomain = isl_union_set_from_set(Stmt->getDomain());
auto *StmtSchedule = isl_schedule_from_domain(UDomain);
LoopData.Schedule = combineInSequence(LoopData.Schedule, StmtSchedule);
}
// Check if we just processed the last node in this loop. If we did, finalize
// the loop by:
//
// - adding new schedule dimensions
// - folding the resulting schedule into the parent loop schedule
// - dropping the loop schedule from the LoopStack.
//
// Then continue to check surrounding loops, which might also have been
// completed by this node.
while (LoopData.L &&
LoopData.NumBlocksProcessed == LoopData.L->getNumBlocks()) {
auto *Schedule = LoopData.Schedule;
auto NumBlocksProcessed = LoopData.NumBlocksProcessed;
LoopStack.pop_back();
auto &NextLoopData = LoopStack.back();
if (Schedule) {
auto *Domain = isl_schedule_get_domain(Schedule);
auto *MUPA = mapToDimension(Domain, LoopStack.size());
Schedule = isl_schedule_insert_partial_schedule(Schedule, MUPA);
NextLoopData.Schedule =
combineInSequence(NextLoopData.Schedule, Schedule);
}
NextLoopData.NumBlocksProcessed += NumBlocksProcessed;
LoopData = NextLoopData;
}
}
ScopStmt *Scop::getStmtFor(BasicBlock *BB) const {
auto StmtMapIt = StmtMap.find(BB);
if (StmtMapIt == StmtMap.end())
return nullptr;
return StmtMapIt->second;
}
ScopStmt *Scop::getStmtFor(RegionNode *RN) const {
if (RN->isSubRegion())
return getStmtFor(RN->getNodeAs<Region>());
return getStmtFor(RN->getNodeAs<BasicBlock>());
}
ScopStmt *Scop::getStmtFor(Region *R) const {
ScopStmt *Stmt = getStmtFor(R->getEntry());
assert(!Stmt || Stmt->getRegion() == R);
return Stmt;
}
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 ScopInfoRegionPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LoopInfoWrapperPass>();
AU.addRequired<RegionInfoPass>();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequiredTransitive<ScalarEvolutionWrapperPass>();
AU.addRequiredTransitive<ScopDetection>();
AU.addRequired<AAResultsWrapperPass>();
AU.addRequired<AssumptionCacheTracker>();
AU.setPreservesAll();
}
bool ScopInfoRegionPass::runOnRegion(Region *R, RGPassManager &RGM) {
auto &SD = getAnalysis<ScopDetection>();
if (!SD.isMaxRegionInScop(*R))
return false;
Function *F = R->getEntry()->getParent();
auto &SE = getAnalysis<ScalarEvolutionWrapperPass>().getSE();
auto &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
auto const &DL = F->getParent()->getDataLayout();
auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(*F);
ScopBuilder SB(R, AC, AA, DL, DT, LI, SD, SE);
S = SB.getScop(); // take ownership of scop object
return false;
}
void ScopInfoRegionPass::print(raw_ostream &OS, const Module *) const {
if (S)
S->print(OS);
else
OS << "Invalid Scop!\n";
}
char ScopInfoRegionPass::ID = 0;
Pass *polly::createScopInfoRegionPassPass() { return new ScopInfoRegionPass(); }
INITIALIZE_PASS_BEGIN(ScopInfoRegionPass, "polly-scops",
"Polly - Create polyhedral description of Scops", false,
false);
INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass);
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker);
INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
INITIALIZE_PASS_DEPENDENCY(RegionInfoPass);
INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass);
INITIALIZE_PASS_DEPENDENCY(ScopDetection);
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass);
INITIALIZE_PASS_END(ScopInfoRegionPass, "polly-scops",
"Polly - Create polyhedral description of Scops", false,
false)
//===----------------------------------------------------------------------===//
void ScopInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LoopInfoWrapperPass>();
AU.addRequired<RegionInfoPass>();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequiredTransitive<ScalarEvolutionWrapperPass>();
AU.addRequiredTransitive<ScopDetection>();
AU.addRequired<AAResultsWrapperPass>();
AU.addRequired<AssumptionCacheTracker>();
AU.setPreservesAll();
}
bool ScopInfoWrapperPass::runOnFunction(Function &F) {
auto &SD = getAnalysis<ScopDetection>();
auto &SE = getAnalysis<ScalarEvolutionWrapperPass>().getSE();
auto &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
auto const &DL = F.getParent()->getDataLayout();
auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
/// Create polyhedral descripton of scops for all the valid regions of a
/// function.
for (auto &It : SD) {
Region *R = const_cast<Region *>(It);
if (!SD.isMaxRegionInScop(*R))
continue;
ScopBuilder SB(R, AC, AA, DL, DT, LI, SD, SE);
bool Inserted =
RegionToScopMap.insert(std::make_pair(R, SB.getScop())).second;
assert(Inserted && "Building Scop for the same region twice!");
(void)Inserted;
}
return false;
}
void ScopInfoWrapperPass::print(raw_ostream &OS, const Module *) const {
for (auto &It : RegionToScopMap) {
if (It.second)
It.second->print(OS);
else
OS << "Invalid Scop!\n";
}
}
char ScopInfoWrapperPass::ID = 0;
Pass *polly::createScopInfoWrapperPassPass() {
return new ScopInfoWrapperPass();
}
INITIALIZE_PASS_BEGIN(
ScopInfoWrapperPass, "polly-function-scops",
"Polly - Create polyhedral description of all Scops of a function", false,
false);
INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass);
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker);
INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
INITIALIZE_PASS_DEPENDENCY(RegionInfoPass);
INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass);
INITIALIZE_PASS_DEPENDENCY(ScopDetection);
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass);
INITIALIZE_PASS_END(
ScopInfoWrapperPass, "polly-function-scops",
"Polly - Create polyhedral description of all Scops of a function", false,
false)
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