Google Git
Sign in
llvm / polly / 1e159f4b75187455c2ee5b060873d7a675840eed / . / lib / Analysis / ScopInfo.cpp
blob: e68551b470f6b955027466967e7d2d8b0d361dd5 [file] [log] [blame]
//===- 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/ScopDetection.h"
#include "polly/Support/GICHelper.h"
#include "polly/Support/ISLOStream.h"
#include "polly/Support/SCEVAffinator.h"
#include "polly/Support/SCEVValidator.h"
#include "polly/Support/ScopHelper.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AliasSetTracker.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/RegionInfo.h"
#include "llvm/Analysis/RegionIterator.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Use.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/Pass.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.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 <algorithm>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <iterator>
#include <memory>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace llvm;
using namespace polly;
#define DEBUG_TYPE "polly-scops"
STATISTIC(AssumptionsAliasing, "Number of aliasing assumptions taken.");
STATISTIC(AssumptionsInbounds, "Number of inbounds assumptions taken.");
STATISTIC(AssumptionsWrapping, "Number of wrapping assumptions taken.");
STATISTIC(AssumptionsUnsigned, "Number of unsigned assumptions taken.");
STATISTIC(AssumptionsComplexity, "Number of too complex SCoPs.");
STATISTIC(AssumptionsUnprofitable, "Number of unprofitable SCoPs.");
STATISTIC(AssumptionsErrorBlock, "Number of error block assumptions taken.");
STATISTIC(AssumptionsInfiniteLoop, "Number of bounded loop assumptions taken.");
STATISTIC(AssumptionsInvariantLoad,
"Number of invariant loads assumptions taken.");
STATISTIC(AssumptionsDelinearization,
"Number of delinearization assumptions taken.");
STATISTIC(NumScops, "Number of feasible SCoPs after ScopInfo");
STATISTIC(NumLoopsInScop, "Number of loops in scops");
STATISTIC(NumBoxedLoops, "Number of boxed loops in SCoPs after ScopInfo");
STATISTIC(NumAffineLoops, "Number of affine loops in SCoPs after ScopInfo");
STATISTIC(NumScopsDepthOne, "Number of scops with maximal loop depth 1");
STATISTIC(NumScopsDepthTwo, "Number of scops with maximal loop depth 2");
STATISTIC(NumScopsDepthThree, "Number of scops with maximal loop depth 3");
STATISTIC(NumScopsDepthFour, "Number of scops with maximal loop depth 4");
STATISTIC(NumScopsDepthFive, "Number of scops with maximal loop depth 5");
STATISTIC(NumScopsDepthLarger,
"Number of scops with maximal loop depth 6 and larger");
STATISTIC(MaxNumLoopsInScop, "Maximal number of loops in scops");
STATISTIC(NumValueWrites, "Number of scalar value writes after ScopInfo");
STATISTIC(
NumValueWritesInLoops,
"Number of scalar value writes nested in affine loops after ScopInfo");
STATISTIC(NumPHIWrites, "Number of scalar phi writes after ScopInfo");
STATISTIC(NumPHIWritesInLoops,
"Number of scalar phi writes nested in affine loops after ScopInfo");
STATISTIC(NumSingletonWrites, "Number of singleton writes after ScopInfo");
STATISTIC(NumSingletonWritesInLoops,
"Number of singleton writes nested in affine loops after ScopInfo");
// 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 MaxDisjunctsInDomain = 20;
// The number of disjunct in the context after which we stop to add more
// disjuncts. This parameter is there to avoid exponential growth in the
// number of disjunct when adding non-convex sets to the context.
static int const MaxDisjunctsInContext = 4;
// The maximal number of dimensions we allow during invariant load construction.
// More complex access ranges will result in very high compile time and are also
// unlikely to result in good code. This value is very high and should only
// trigger for corner cases (e.g., the "dct_luma" function in h264, SPEC2006).
static int const MaxDimensionsInAccessRange = 9;
static cl::opt<int>
OptComputeOut("polly-analysis-computeout",
cl::desc("Bound the scop analysis by a maximal amount of "
"computational steps (0 means no bound)"),
cl::Hidden, cl::init(800000), cl::ZeroOrMore,
cl::cat(PollyCategory));
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));
static cl::opt<int> RunTimeChecksMaxAccessDisjuncts(
"polly-rtc-max-array-disjuncts",
cl::desc("The maximal number of disjunts allowed in memory accesses to "
"to build RTCs."),
cl::Hidden, cl::ZeroOrMore, cl::init(8), 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>
IslOnErrorAbort("polly-on-isl-error-abort",
cl::desc("Abort if an isl error is encountered"),
cl::init(true), cl::cat(PollyCategory));
static cl::opt<bool> PollyPreciseInbounds(
"polly-precise-inbounds",
cl::desc("Take more precise inbounds assumptions (do not scale well)"),
cl::Hidden, cl::init(false), cl::cat(PollyCategory));
static cl::opt<bool>
PollyIgnoreInbounds("polly-ignore-inbounds",
cl::desc("Do not take inbounds assumptions at all"),
cl::Hidden, cl::init(false), cl::cat(PollyCategory));
static cl::opt<bool> PollyIgnoreParamBounds(
"polly-ignore-parameter-bounds",
cl::desc(
"Do not add parameter bounds and do no gist simplify sets accordingly"),
cl::Hidden, cl::init(false), cl::cat(PollyCategory));
static cl::opt<bool> PollyAllowDereferenceOfAllFunctionParams(
"polly-allow-dereference-of-all-function-parameters",
cl::desc(
"Treat all parameters to functions that are pointers as dereferencible."
" This is useful for invariant load hoisting, since we can generate"
" less runtime checks. This is only valid if all pointers to functions"
" are always initialized, so that Polly can choose to hoist"
" their loads. "),
cl::Hidden, cl::init(false), cl::cat(PollyCategory));
static cl::opt<bool> PollyPreciseFoldAccesses(
"polly-precise-fold-accesses",
cl::desc("Fold memory accesses to model more possible delinearizations "
"(does not scale well)"),
cl::Hidden, cl::init(false), cl::cat(PollyCategory));
bool polly::UseInstructionNames;
static cl::opt<bool, true> XUseInstructionNames(
"polly-use-llvm-names",
cl::desc("Use LLVM-IR names when deriving statement names"),
cl::location(UseInstructionNames), cl::Hidden, cl::init(false),
cl::ZeroOrMore, cl::cat(PollyCategory));
static cl::opt<bool> PollyPrintInstructions(
"polly-print-instructions", cl::desc("Output instructions per ScopStmt"),
cl::Hidden, cl::Optional, cl::init(false), cl::cat(PollyCategory));
//===----------------------------------------------------------------------===//
// Create a sequence of two schedules. Either argument may be null and is
// interpreted as the empty schedule. Can also return null if both schedules are
// empty.
static isl::schedule combineInSequence(isl::schedule Prev, isl::schedule Succ) {
if (!Prev)
return Succ;
if (!Succ)
return Prev;
return Prev.sequence(Succ);
}
static isl::set addRangeBoundsToSet(isl::set S, const ConstantRange &Range,
int dim, isl::dim type) {
isl::val V;
isl::ctx Ctx = S.get_ctx();
// The upper and lower bound for a parameter value is derived either from
// the data type of the parameter or from the - possibly more restrictive -
// range metadata.
V = valFromAPInt(Ctx.get(), Range.getSignedMin(), true);
S = S.lower_bound_val(type, dim, V);
V = valFromAPInt(Ctx.get(), Range.getSignedMax(), true);
S = S.upper_bound_val(type, dim, V);
if (Range.isFullSet())
return S;
if (isl_set_n_basic_set(S.get()) > MaxDisjunctsInContext)
return S;
// In case of signed wrapping, we can refine the set of valid values by
// excluding the part not covered by the wrapping range.
if (Range.isSignWrappedSet()) {
V = valFromAPInt(Ctx.get(), Range.getLower(), true);
isl::set SLB = S.lower_bound_val(type, dim, V);
V = valFromAPInt(Ctx.get(), Range.getUpper(), true);
V = V.sub_ui(1);
isl::set SUB = S.upper_bound_val(type, dim, V);
S = SLB.unite(SUB);
}
return S;
}
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(),
MemoryKind::Array);
}
ScopArrayInfo::ScopArrayInfo(Value *BasePtr, Type *ElementType, isl::ctx Ctx,
ArrayRef<const SCEV *> Sizes, MemoryKind Kind,
const DataLayout &DL, Scop *S,
const char *BaseName)
: BasePtr(BasePtr), ElementType(ElementType), Kind(Kind), DL(DL), S(*S) {
std::string BasePtrName =
BaseName ? BaseName
: getIslCompatibleName("MemRef", BasePtr, S->getNextArrayIdx(),
Kind == MemoryKind::PHI ? "__phi" : "",
UseInstructionNames);
Id = isl::id::alloc(Ctx, BasePtrName, this);
updateSizes(Sizes);
if (!BasePtr || Kind != MemoryKind::Array) {
BasePtrOriginSAI = nullptr;
return;
}
BasePtrOriginSAI = identifyBasePtrOriginSAI(S, BasePtr);
if (BasePtrOriginSAI)
const_cast<ScopArrayInfo *>(BasePtrOriginSAI)->addDerivedSAI(this);
}
ScopArrayInfo::~ScopArrayInfo() = default;
isl::space ScopArrayInfo::getSpace() const {
auto Space = isl::space(Id.get_ctx(), 0, getNumberOfDimensions());
Space = Space.set_tuple_id(isl::dim::set, Id);
return Space;
}
bool ScopArrayInfo::isReadOnly() {
isl::union_set WriteSet = S.getWrites().range();
isl::space Space = getSpace();
WriteSet = WriteSet.extract_set(Space);
return bool(WriteSet.is_empty());
}
bool ScopArrayInfo::isCompatibleWith(const ScopArrayInfo *Array) const {
if (Array->getElementType() != getElementType())
return false;
if (Array->getNumberOfDimensions() != getNumberOfDimensions())
return false;
for (unsigned i = 0; i < getNumberOfDimensions(); i++)
if (Array->getDimensionSize(i) != getDimensionSize(i))
return false;
return true;
}
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);
}
}
/// Make the ScopArrayInfo model a Fortran Array
void ScopArrayInfo::applyAndSetFAD(Value *FAD) {
assert(FAD && "got invalid Fortran array descriptor");
if (this->FAD) {
assert(this->FAD == FAD &&
"receiving different array descriptors for same array");
return;
}
assert(DimensionSizesPw.size() > 0 && !DimensionSizesPw[0]);
assert(!this->FAD);
this->FAD = FAD;
isl::space Space(S.getIslCtx(), 1, 0);
std::string param_name = getName();
param_name += "_fortranarr_size";
isl::id IdPwAff = isl::id::alloc(S.getIslCtx(), param_name, this);
Space = Space.set_dim_id(isl::dim::param, 0, IdPwAff);
isl::pw_aff PwAff =
isl::aff::var_on_domain(isl::local_space(Space), isl::dim::param, 0);
DimensionSizesPw[0] = PwAff;
}
bool ScopArrayInfo::updateSizes(ArrayRef<const SCEV *> NewSizes,
bool CheckConsistency) {
int SharedDims = std::min(NewSizes.size(), DimensionSizes.size());
int ExtraDimsNew = NewSizes.size() - SharedDims;
int ExtraDimsOld = DimensionSizes.size() - SharedDims;
if (CheckConsistency) {
for (int i = 0; i < SharedDims; i++) {
auto *NewSize = NewSizes[i + ExtraDimsNew];
auto *KnownSize = DimensionSizes[i + ExtraDimsOld];
if (NewSize && KnownSize && NewSize != KnownSize)
return false;
}
if (DimensionSizes.size() >= NewSizes.size())
return true;
}
DimensionSizes.clear();
DimensionSizes.insert(DimensionSizes.begin(), NewSizes.begin(),
NewSizes.end());
DimensionSizesPw.clear();
for (const SCEV *Expr : DimensionSizes) {
if (!Expr) {
DimensionSizesPw.push_back(nullptr);
continue;
}
isl::pw_aff Size = S.getPwAffOnly(Expr);
DimensionSizesPw.push_back(Size);
}
return true;
}
std::string ScopArrayInfo::getName() const { return Id.get_name(); }
int ScopArrayInfo::getElemSizeInBytes() const {
return DL.getTypeAllocSize(ElementType);
}
isl::id ScopArrayInfo::getBasePtrId() const { return Id; }
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void ScopArrayInfo::dump() const { print(errs()); }
#endif
void ScopArrayInfo::print(raw_ostream &OS, bool SizeAsPwAff) const {
OS.indent(8) << *getElementType() << " " << getName();
unsigned u = 0;
// If this is a Fortran array, then we can print the outermost dimension
// as a isl_pw_aff even though there is no SCEV information.
bool IsOutermostSizeKnown = SizeAsPwAff && FAD;
if (!IsOutermostSizeKnown && getNumberOfDimensions() > 0 &&
!getDimensionSize(0)) {
OS << "[*]";
u++;
}
for (; u < getNumberOfDimensions(); u++) {
OS << "[";
if (SizeAsPwAff) {
isl::pw_aff Size = getDimensionSizePw(u);
OS << " " << Size << " ";
} else {
OS << *getDimensionSize(u);
}
OS << "]";
}
OS << ";";
if (BasePtrOriginSAI)
OS << " [BasePtrOrigin: " << BasePtrOriginSAI->getName() << "]";
OS << " // Element size " << getElemSizeInBytes() << "\n";
}
const ScopArrayInfo *
ScopArrayInfo::getFromAccessFunction(isl::pw_multi_aff PMA) {
isl::id Id = PMA.get_tuple_id(isl::dim::out);
assert(!Id.is_null() && "Output dimension didn't have an ID");
return getFromId(Id);
}
const ScopArrayInfo *ScopArrayInfo::getFromId(isl::id Id) {
void *User = Id.get_user();
const ScopArrayInfo *SAI = static_cast<ScopArrayInfo *>(User);
return SAI;
}
void MemoryAccess::wrapConstantDimensions() {
auto *SAI = getScopArrayInfo();
isl::space ArraySpace = SAI->getSpace();
isl::ctx Ctx = ArraySpace.get_ctx();
unsigned DimsArray = SAI->getNumberOfDimensions();
isl::multi_aff DivModAff = isl::multi_aff::identity(
ArraySpace.map_from_domain_and_range(ArraySpace));
isl::local_space LArraySpace = isl::local_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;
// This transformation is not applicable to dimensions of size zero.
if (DimSize->isZero())
continue;
isl::val DimSizeVal =
valFromAPInt(Ctx.get(), DimSizeCst->getAPInt(), false);
isl::aff Var = isl::aff::var_on_domain(LArraySpace, isl::dim::set, i);
isl::aff PrevVar =
isl::aff::var_on_domain(LArraySpace, isl::dim::set, i - 1);
// Compute: index % size
// Modulo must apply in the divide of the previous iteration, if any.
isl::aff Modulo = Var.mod(DimSizeVal);
Modulo = Modulo.pullback(DivModAff);
// Compute: floor(index / size)
isl::aff Divide = Var.div(isl::aff(LArraySpace, DimSizeVal));
Divide = Divide.floor();
Divide = Divide.add(PrevVar);
Divide = Divide.pullback(DivModAff);
// Apply Modulo and Divide.
DivModAff = DivModAff.set_aff(i, Modulo);
DivModAff = DivModAff.set_aff(i - 1, Divide);
}
// Apply all modulo/divides on the accesses.
isl::map Relation = AccessRelation;
Relation = Relation.apply_range(isl::map::from_multi_aff(DivModAff));
Relation = Relation.detect_equalities();
AccessRelation = Relation;
}
void MemoryAccess::updateDimensionality() {
auto *SAI = getScopArrayInfo();
isl::space ArraySpace = SAI->getSpace();
isl::space AccessSpace = AccessRelation.get_space().range();
isl::ctx Ctx = ArraySpace.get_ctx();
auto DimsArray = ArraySpace.dim(isl::dim::set);
auto DimsAccess = AccessSpace.dim(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());
isl::map Map = isl::map::from_domain_and_range(
isl::set::universe(AccessSpace), isl::set::universe(ArraySpace));
for (unsigned i = 0; i < DimsMissing; i++)
Map = Map.fix_si(isl::dim::out, i, 0);
for (unsigned i = DimsMissing; i < DimsArray; i++)
Map = Map.equate(isl::dim::in, i - DimsMissing, isl::dim::out, i);
AccessRelation = AccessRelation.apply_range(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 chosen a smaller ArrayElemSize
// that divides the offsets of all accesses to this base pointer.
if (DimsAccess == 1) {
isl::val V = isl::val(Ctx, ArrayElemSize);
AccessRelation = AccessRelation.floordiv_val(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");
isl::map Map = isl::map::from_domain_and_range(
isl::set::universe(ArraySpace), isl::set::universe(ArraySpace));
for (unsigned i = 0; i < DimsArray - 1; i++)
Map = Map.equate(isl::dim::in, i, isl::dim::out, i);
isl::constraint C;
isl::local_space LS;
LS = isl::local_space(Map.get_space());
int Num = ElemBytes / getScopArrayInfo()->getElemSizeInBytes();
C = isl::constraint::alloc_inequality(LS);
C = C.set_constant_val(isl::val(Ctx, Num - 1));
C = C.set_coefficient_si(isl::dim::in, DimsArray - 1, 1);
C = C.set_coefficient_si(isl::dim::out, DimsArray - 1, -1);
Map = Map.add_constraint(C);
C = isl::constraint::alloc_inequality(LS);
C = C.set_coefficient_si(isl::dim::in, DimsArray - 1, -1);
C = C.set_coefficient_si(isl::dim::out, DimsArray - 1, 1);
C = C.set_constant_val(isl::val(Ctx, 0));
Map = Map.add_constraint(C);
AccessRelation = AccessRelation.apply_range(Map);
}
}
const std::string
MemoryAccess::getReductionOperatorStr(MemoryAccess::ReductionType RT) {
switch (RT) {
case MemoryAccess::RT_NONE:
llvm_unreachable("Requested a reduction operator string for a memory "
"access which isn't a reduction");
case MemoryAccess::RT_ADD:
return "+";
case MemoryAccess::RT_MUL:
return "*";
case MemoryAccess::RT_BOR:
return "|";
case MemoryAccess::RT_BXOR:
return "^";
case MemoryAccess::RT_BAND:
return "&";
}
llvm_unreachable("Unknown reduction type");
}
const ScopArrayInfo *MemoryAccess::getOriginalScopArrayInfo() const {
isl::id ArrayId = getArrayId();
void *User = ArrayId.get_user();
const ScopArrayInfo *SAI = static_cast<ScopArrayInfo *>(User);
return SAI;
}
const ScopArrayInfo *MemoryAccess::getLatestScopArrayInfo() const {
isl::id ArrayId = getLatestArrayId();
void *User = ArrayId.get_user();
const ScopArrayInfo *SAI = static_cast<ScopArrayInfo *>(User);
return SAI;
}
isl::id MemoryAccess::getOriginalArrayId() const {
return AccessRelation.get_tuple_id(isl::dim::out);
}
isl::id MemoryAccess::getLatestArrayId() const {
if (!hasNewAccessRelation())
return getOriginalArrayId();
return NewAccessRelation.get_tuple_id(isl::dim::out);
}
isl::map MemoryAccess::getAddressFunction() const {
return getAccessRelation().lexmin();
}
isl::pw_multi_aff
MemoryAccess::applyScheduleToAccessRelation(isl::union_map USchedule) const {
isl::map Schedule, ScheduledAccRel;
isl::union_set UDomain;
UDomain = getStatement()->getDomain();
USchedule = USchedule.intersect_domain(UDomain);
Schedule = isl::map::from_union_map(USchedule);
ScheduledAccRel = getAddressFunction().apply_domain(Schedule);
return isl::pw_multi_aff::from_map(ScheduledAccRel);
}
isl::map MemoryAccess::getOriginalAccessRelation() const {
return AccessRelation;
}
std::string MemoryAccess::getOriginalAccessRelationStr() const {
return AccessRelation.to_str();
}
isl::space MemoryAccess::getOriginalAccessRelationSpace() const {
return AccessRelation.get_space();
}
isl::map MemoryAccess::getNewAccessRelation() const {
return NewAccessRelation;
}
std::string MemoryAccess::getNewAccessRelationStr() const {
return NewAccessRelation.to_str();
}
std::string MemoryAccess::getAccessRelationStr() const {
return getAccessRelation().to_str();
}
isl::basic_map MemoryAccess::createBasicAccessMap(ScopStmt *Statement) {
isl::space Space = isl::space(Statement->getIslCtx(), 0, 1);
Space = Space.align_params(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() {
if (PollyIgnoreInbounds)
return;
auto *SAI = getScopArrayInfo();
isl::space Space = getOriginalAccessRelationSpace().range();
isl::set Outside = isl::set::empty(Space);
for (int i = 1, Size = Space.dim(isl::dim::set); i < Size; ++i) {
isl::local_space LS(Space);
isl::pw_aff Var = isl::pw_aff::var_on_domain(LS, isl::dim::set, i);
isl::pw_aff Zero = isl::pw_aff(LS);
isl::set DimOutside = Var.lt_set(Zero);
isl::pw_aff SizeE = SAI->getDimensionSizePw(i);
SizeE = SizeE.add_dims(isl::dim::in, Space.dim(isl::dim::set));
SizeE = SizeE.set_tuple_id(isl::dim::in, Space.get_tuple_id(isl::dim::set));
DimOutside = DimOutside.unite(SizeE.le_set(Var));
Outside = Outside.unite(DimOutside);
}
Outside = Outside.apply(getAccessRelation().reverse());
Outside = Outside.intersect(Statement->getDomain());
Outside = Outside.params();
// 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 = Outside.remove_divs();
Outside = Outside.complement();
const auto &Loc = getAccessInstruction()
? getAccessInstruction()->getDebugLoc()
: DebugLoc();
if (!PollyPreciseInbounds)
Outside = Outside.gist_params(Statement->getDomain().params());
Statement->getParent()->recordAssumption(INBOUNDS, Outside, Loc,
AS_ASSUMPTION);
}
void MemoryAccess::buildMemIntrinsicAccessRelation() {
assert(isMemoryIntrinsic());
assert(Subscripts.size() == 2 && Sizes.size() == 1);
isl::pw_aff SubscriptPWA = getPwAff(Subscripts[0]);
isl::map SubscriptMap = isl::map::from_pw_aff(SubscriptPWA);
isl::map LengthMap;
if (Subscripts[1] == nullptr) {
LengthMap = isl::map::universe(SubscriptMap.get_space());
} else {
isl::pw_aff LengthPWA = getPwAff(Subscripts[1]);
LengthMap = isl::map::from_pw_aff(LengthPWA);
isl::space RangeSpace = LengthMap.get_space().range();
LengthMap = LengthMap.apply_range(isl::map::lex_gt(RangeSpace));
}
LengthMap = LengthMap.lower_bound_si(isl::dim::out, 0, 0);
LengthMap = LengthMap.align_params(SubscriptMap.get_space());
SubscriptMap = SubscriptMap.align_params(LengthMap.get_space());
LengthMap = LengthMap.sum(SubscriptMap);
AccessRelation =
LengthMap.set_tuple_id(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;
if (Range.isWrappedSet() || Range.isSignWrappedSet())
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;
assert(Min.sle(Max) && "Minimum expected to be less or equal than max");
isl::map Relation = AccessRelation;
isl::set AccessRange = Relation.range();
AccessRange = addRangeBoundsToSet(AccessRange, ConstantRange(Min, Max), 0,
isl::dim::set);
AccessRelation = Relation.intersect_range(AccessRange);
}
void MemoryAccess::foldAccessRelation() {
if (Sizes.size() < 2 || isa<SCEVConstant>(Sizes[1]))
return;
int Size = Subscripts.size();
isl::map NewAccessRelation = AccessRelation;
for (int i = Size - 2; i >= 0; --i) {
isl::space Space;
isl::map MapOne, MapTwo;
isl::pw_aff DimSize = getPwAff(Sizes[i + 1]);
isl::space SpaceSize = DimSize.get_space();
isl::id ParamId =
give(isl_space_get_dim_id(SpaceSize.get(), isl_dim_param, 0));
Space = AccessRelation.get_space();
Space = Space.range().map_from_set();
Space = Space.align_params(SpaceSize);
int ParamLocation = Space.find_dim_by_id(isl::dim::param, ParamId);
MapOne = isl::map::universe(Space);
for (int j = 0; j < Size; ++j)
MapOne = MapOne.equate(isl::dim::in, j, isl::dim::out, j);
MapOne = MapOne.lower_bound_si(isl::dim::in, i + 1, 0);
MapTwo = isl::map::universe(Space);
for (int j = 0; j < Size; ++j)
if (j < i || j > i + 1)
MapTwo = MapTwo.equate(isl::dim::in, j, isl::dim::out, j);
isl::local_space LS(Space);
isl::constraint C;
C = isl::constraint::alloc_equality(LS);
C = C.set_constant_si(-1);
C = C.set_coefficient_si(isl::dim::in, i, 1);
C = C.set_coefficient_si(isl::dim::out, i, -1);
MapTwo = MapTwo.add_constraint(C);
C = isl::constraint::alloc_equality(LS);
C = C.set_coefficient_si(isl::dim::in, i + 1, 1);
C = C.set_coefficient_si(isl::dim::out, i + 1, -1);
C = C.set_coefficient_si(isl::dim::param, ParamLocation, 1);
MapTwo = MapTwo.add_constraint(C);
MapTwo = MapTwo.upper_bound_si(isl::dim::in, i + 1, -1);
MapOne = MapOne.unite(MapTwo);
NewAccessRelation = NewAccessRelation.apply_range(MapOne);
}
isl::id BaseAddrId = getScopArrayInfo()->getBasePtrId();
isl::space Space = Statement->getDomainSpace();
NewAccessRelation = NewAccessRelation.set_tuple_id(
isl::dim::in, Space.get_tuple_id(isl::dim::set));
NewAccessRelation = NewAccessRelation.set_tuple_id(isl::dim::out, BaseAddrId);
NewAccessRelation = NewAccessRelation.gist_domain(Statement->getDomain());
// Access dimension folding might in certain cases increase the number of
// disjuncts in the memory access, which can possibly complicate the generated
// run-time checks and can lead to costly compilation.
if (!PollyPreciseFoldAccesses &&
isl_map_n_basic_map(NewAccessRelation.get()) >
isl_map_n_basic_map(AccessRelation.get())) {
} else {
AccessRelation = NewAccessRelation;
}
}
/// 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 divisible.
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.is_null() && "AccessRelation already built");
// Initialize the invalid domain which describes all iterations for which the
// access relation is not modeled correctly.
isl::set StmtInvalidDomain = getStatement()->getInvalidDomain();
InvalidDomain = isl::set::empty(StmtInvalidDomain.get_space());
isl::ctx Ctx = Id.get_ctx();
isl::id BaseAddrId = SAI->getBasePtrId();
if (getAccessInstruction() && isa<MemIntrinsic>(getAccessInstruction())) {
buildMemIntrinsicAccessRelation();
AccessRelation = AccessRelation.set_tuple_id(isl::dim::out, BaseAddrId);
return;
}
if (!isAffine()) {
// We overapproximate non-affine accesses with a possible access to the
// whole array. For read accesses it does not make a difference, if an
// access must or may happen. However, for write accesses it is important to
// differentiate between writes that must happen and writes that may happen.
if (AccessRelation.is_null())
AccessRelation = createBasicAccessMap(Statement);
AccessRelation = AccessRelation.set_tuple_id(isl::dim::out, BaseAddrId);
return;
}
isl::space Space = isl::space(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 = AccessRelation.flat_range_product(SubscriptMap);
}
Space = Statement->getDomainSpace();
AccessRelation = AccessRelation.set_tuple_id(
isl::dim::in, Space.get_tuple_id(isl::dim::set));
AccessRelation = AccessRelation.set_tuple_id(isl::dim::out, BaseAddrId);
AccessRelation = AccessRelation.gist_domain(Statement->getDomain());
}
MemoryAccess::MemoryAccess(ScopStmt *Stmt, Instruction *AccessInst,
AccessType AccType, Value *BaseAddress,
Type *ElementType, bool Affine,
ArrayRef<const SCEV *> Subscripts,
ArrayRef<const SCEV *> Sizes, Value *AccessValue,
MemoryKind Kind)
: Kind(Kind), AccType(AccType), Statement(Stmt), InvalidDomain(nullptr),
BaseAddr(BaseAddress), ElementType(ElementType),
Sizes(Sizes.begin(), Sizes.end()), AccessInstruction(AccessInst),
AccessValue(AccessValue), IsAffine(Affine),
Subscripts(Subscripts.begin(), Subscripts.end()), AccessRelation(nullptr),
NewAccessRelation(nullptr), FAD(nullptr) {
static const std::string TypeStrings[] = {"", "_Read", "_Write", "_MayWrite"};
const std::string Access = TypeStrings[AccType] + utostr(Stmt->size());
std::string IdName = Stmt->getBaseName() + Access;
Id = isl::id::alloc(Stmt->getParent()->getIslCtx(), IdName, this);
}
MemoryAccess::MemoryAccess(ScopStmt *Stmt, AccessType AccType, isl::map AccRel)
: Kind(MemoryKind::Array), AccType(AccType), Statement(Stmt),
InvalidDomain(nullptr), AccessRelation(nullptr),
NewAccessRelation(AccRel), FAD(nullptr) {
isl::id ArrayInfoId = NewAccessRelation.get_tuple_id(isl::dim::out);
auto *SAI = ScopArrayInfo::getFromId(ArrayInfoId);
Sizes.push_back(nullptr);
for (unsigned i = 1; i < SAI->getNumberOfDimensions(); i++)
Sizes.push_back(SAI->getDimensionSize(i));
ElementType = SAI->getElementType();
BaseAddr = SAI->getBasePtr();
static const std::string TypeStrings[] = {"", "_Read", "_Write", "_MayWrite"};
const std::string Access = TypeStrings[AccType] + utostr(Stmt->size());
std::string IdName = Stmt->getBaseName() + Access;
Id = isl::id::alloc(Stmt->getParent()->getIslCtx(), IdName, this);
}
MemoryAccess::~MemoryAccess() = default;
void MemoryAccess::realignParams() {
isl::set Ctx = Statement->getParent()->getContext();
InvalidDomain = InvalidDomain.gist_params(Ctx);
AccessRelation = AccessRelation.gist_params(Ctx);
}
const std::string MemoryAccess::getReductionOperatorStr() const {
return MemoryAccess::getReductionOperatorStr(getReductionType());
}
isl::id MemoryAccess::getId() const { return 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::setFortranArrayDescriptor(Value *FAD) { this->FAD = FAD; }
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() << "] ";
if (FAD) {
OS << "[Fortran array descriptor: " << FAD->getName();
OS << "] ";
};
OS << "[Scalar: " << isScalarKind() << "]\n";
OS.indent(16) << getOriginalAccessRelationStr() << ";\n";
if (hasNewAccessRelation())
OS.indent(11) << "new: " << getNewAccessRelationStr() << ";\n";
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void MemoryAccess::dump() const { print(errs()); }
#endif
isl::pw_aff MemoryAccess::getPwAff(const SCEV *E) {
auto *Stmt = getStatement();
PWACtx PWAC = Stmt->getParent()->getPwAff(E, Stmt->getEntryBlock());
isl::set StmtDom = getStatement()->getDomain();
StmtDom = StmtDom.reset_tuple_id();
isl::set NewInvalidDom = StmtDom.intersect(PWAC.second);
InvalidDomain = InvalidDomain.unite(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 = SetDomain.map_from_set();
isl::map Map = isl::map::universe(Space);
unsigned lastDimension = Map.dim(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 = Map.equate(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 = Map.order_lt(isl::dim::in, lastDimension, isl::dim::out, lastDimension);
return Map;
}
isl::set MemoryAccess::getStride(isl::map Schedule) const {
isl::map AccessRelation = getAccessRelation();
isl::space Space = Schedule.get_space().range();
isl::map NextScatt = getEqualAndLarger(Space);
Schedule = Schedule.reverse();
NextScatt = NextScatt.lexmin();
NextScatt = NextScatt.apply_range(Schedule);
NextScatt = NextScatt.apply_range(AccessRelation);
NextScatt = NextScatt.apply_domain(Schedule);
NextScatt = NextScatt.apply_domain(AccessRelation);
isl::set Deltas = NextScatt.deltas();
return Deltas;
}
bool MemoryAccess::isStrideX(isl::map Schedule, int StrideWidth) const {
isl::set Stride, StrideX;
bool IsStrideX;
Stride = getStride(Schedule);
StrideX = isl::set::universe(Stride.get_space());
for (unsigned i = 0; i < StrideX.dim(isl::dim::set) - 1; i++)
StrideX = StrideX.fix_si(isl::dim::set, i, 0);
StrideX = StrideX.fix_si(isl::dim::set, StrideX.dim(isl::dim::set) - 1,
StrideWidth);
IsStrideX = Stride.is_subset(StrideX);
return IsStrideX;
}
bool MemoryAccess::isStrideZero(isl::map Schedule) const {
return isStrideX(Schedule, 0);
}
bool MemoryAccess::isStrideOne(isl::map Schedule) const {
return isStrideX(Schedule, 1);
}
void MemoryAccess::setAccessRelation(isl::map NewAccess) {
AccessRelation = NewAccess;
}
void MemoryAccess::setNewAccessRelation(isl::map NewAccess) {
assert(NewAccess);
#ifndef NDEBUG
// Check domain space compatibility.
isl::space NewSpace = NewAccess.get_space();
isl::space NewDomainSpace = NewSpace.domain();
isl::space OriginalDomainSpace = getStatement()->getDomainSpace();
assert(OriginalDomainSpace.has_equal_tuples(NewDomainSpace));
// Reads must be executed unconditionally. Writes might be executed in a
// subdomain only.
if (isRead()) {
// Check whether there is an access for every statement instance.
isl::set StmtDomain = getStatement()->getDomain();
StmtDomain =
StmtDomain.intersect_params(getStatement()->getParent()->getContext());
isl::set NewDomain = NewAccess.domain();
assert(StmtDomain.is_subset(NewDomain) &&
"Partial READ accesses not supported");
}
isl::space NewAccessSpace = NewAccess.get_space();
assert(NewAccessSpace.has_tuple_id(isl::dim::set) &&
"Must specify the array that is accessed");
isl::id NewArrayId = NewAccessSpace.get_tuple_id(isl::dim::set);
auto *SAI = static_cast<ScopArrayInfo *>(NewArrayId.get_user());
assert(SAI && "Must set a ScopArrayInfo");
if (SAI->isArrayKind() && SAI->getBasePtrOriginSAI()) {
InvariantEquivClassTy *EqClass =
getStatement()->getParent()->lookupInvariantEquivClass(
SAI->getBasePtr());
assert(EqClass &&
"Access functions to indirect arrays must have an invariant and "
"hoisted base pointer");
}
// Check whether access dimensions correspond to number of dimensions of the
// accesses array.
auto Dims = SAI->getNumberOfDimensions();
assert(NewAccessSpace.dim(isl::dim::set) == Dims &&
"Access dims must match array dims");
#endif
NewAccess = NewAccess.gist_domain(getStatement()->getDomain());
NewAccessRelation = NewAccess;
}
bool MemoryAccess::isLatestPartialAccess() const {
isl::set StmtDom = getStatement()->getDomain();
isl::set AccDom = getLatestAccessRelation().domain();
return isl_set_is_subset(StmtDom.keep(), AccDom.keep()) == isl_bool_false;
}
//===----------------------------------------------------------------------===//
isl::map ScopStmt::getSchedule() const {
isl::set Domain = getDomain();
if (Domain.is_empty())
return isl::map::from_aff(isl::aff(isl::local_space(getDomainSpace())));
auto Schedule = getParent()->getSchedule();
if (!Schedule)
return nullptr;
Schedule = Schedule.intersect_domain(isl::union_set(Domain));
if (Schedule.is_empty())
return isl::map::from_aff(isl::aff(isl::local_space(getDomainSpace())));
isl::map M = M.from_union_map(Schedule);
M = M.coalesce();
M = M.gist_domain(Domain);
M = M.coalesce();
return M;
}
void ScopStmt::restrictDomain(isl::set NewDomain) {
assert(NewDomain.is_subset(Domain) &&
"New domain is not a subset of old domain!");
Domain = NewDomain;
}
void ScopStmt::addAccess(MemoryAccess *Access, bool Prepend) {
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(!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->getAccessValue());
assert(!PHIWrites.lookup(PHI));
PHIWrites[PHI] = Access;
} else if (Access->isAnyPHIKind() && Access->isRead()) {
PHINode *PHI = cast<PHINode>(Access->getAccessValue());
assert(!PHIReads.lookup(PHI));
PHIReads[PHI] = Access;
}
if (Prepend) {
MemAccs.insert(MemAccs.begin(), Access);
return;
}
MemAccs.push_back(Access);
}
void ScopStmt::realignParams() {
for (MemoryAccess *MA : *this)
MA->realignParams();
isl::set Ctx = Parent.getContext();
InvalidDomain = InvalidDomain.gist_params(Ctx);
Domain = Domain.gist_params(Ctx);
}
/// 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;
}
/// 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;
}
/// 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);
}
/// 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");
}
}
/// Compute the isl representation for the SCEV @p E in this BB.
///
/// @param S The Scop in which @p BB resides in.
/// @param BB The BB for which isl representation is to be
/// computed.
/// @param InvalidDomainMap A map of BB to their invalid domains.
/// @param E The SCEV that should be translated.
/// @param NonNegative Flag to indicate the @p E has to be non-negative.
///
/// Note that this function will also adjust the invalid context accordingly.
__isl_give isl_pw_aff *
getPwAff(Scop &S, BasicBlock *BB,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap, const SCEV *E,
bool NonNegative = false) {
PWACtx PWAC = S.getPwAff(E, BB, NonNegative);
InvalidDomainMap[BB] = InvalidDomainMap[BB].unite(PWAC.second);
return PWAC.first.take();
}
/// 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.
bool buildConditionSets(Scop &S, BasicBlock *BB, SwitchInst *SI, Loop *L,
__isl_keep isl_set *Domain,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
Value *Condition = getConditionFromTerminator(SI);
assert(Condition && "No condition for switch");
ScalarEvolution &SE = *S.getSE();
isl_pw_aff *LHS, *RHS;
LHS = getPwAff(S, BB, InvalidDomainMap, 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 = getPwAff(S, BB, InvalidDomainMap, SE.getSCEV(CaseValue));
isl_set *CaseConditionSet =
buildConditionSet(ICmpInst::ICMP_EQ, isl_pw_aff_copy(LHS), RHS);
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] = isl_set_subtract(isl_set_copy(Domain), ConditionSetUnion);
isl_pw_aff_free(LHS);
return true;
}
/// Build condition sets for unsigned ICmpInst(s).
/// Special handling is required for unsigned operands to ensure that if
/// MSB (aka the Sign bit) is set for an operands in an unsigned ICmpInst
/// it should wrap around.
///
/// @param IsStrictUpperBound holds information on the predicate relation
/// between TestVal and UpperBound, i.e,
/// TestVal < UpperBound OR TestVal <= UpperBound
__isl_give isl_set *
buildUnsignedConditionSets(Scop &S, BasicBlock *BB, Value *Condition,
__isl_keep isl_set *Domain, const SCEV *SCEV_TestVal,
const SCEV *SCEV_UpperBound,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
bool IsStrictUpperBound) {
// Do not take NonNeg assumption on TestVal
// as it might have MSB (Sign bit) set.
isl_pw_aff *TestVal = getPwAff(S, BB, InvalidDomainMap, SCEV_TestVal, false);
// Take NonNeg assumption on UpperBound.
isl_pw_aff *UpperBound =
getPwAff(S, BB, InvalidDomainMap, SCEV_UpperBound, true);
// 0 <= TestVal
isl_set *First =
isl_pw_aff_le_set(isl_pw_aff_zero_on_domain(isl_local_space_from_space(
isl_pw_aff_get_domain_space(TestVal))),
isl_pw_aff_copy(TestVal));
isl_set *Second;
if (IsStrictUpperBound)
// TestVal < UpperBound
Second = isl_pw_aff_lt_set(TestVal, UpperBound);
else
// TestVal <= UpperBound
Second = isl_pw_aff_le_set(TestVal, UpperBound);
isl_set *ConsequenceCondSet = isl_set_intersect(First, Second);
return ConsequenceCondSet;
}
/// 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.
bool buildConditionSets(Scop &S, BasicBlock *BB, Value *Condition,
TerminatorInst *TI, Loop *L, __isl_keep isl_set *Domain,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
ScalarEvolution &SE = *S.getSE();
isl_set *ConsequenceCondSet = nullptr;
if (auto Load = dyn_cast<LoadInst>(Condition)) {
const SCEV *LHSSCEV = SE.getSCEVAtScope(Load, L);
const SCEV *RHSSCEV = SE.getZero(LHSSCEV->getType());
bool NonNeg = false;
isl_pw_aff *LHS = getPwAff(S, BB, InvalidDomainMap, LHSSCEV, NonNeg);
isl_pw_aff *RHS = getPwAff(S, BB, InvalidDomainMap, RHSSCEV, NonNeg);
ConsequenceCondSet = buildConditionSet(ICmpInst::ICMP_SLE, LHS, RHS);
} else if (auto *PHI = dyn_cast<PHINode>(Condition)) {
auto *Unique = dyn_cast<ConstantInt>(
getUniqueNonErrorValue(PHI, &S.getRegion(), *S.getLI(), *S.getDT()));
if (Unique->isZero())
ConsequenceCondSet = isl_set_empty(isl_set_get_space(Domain));
else
ConsequenceCondSet = isl_set_universe(isl_set_get_space(Domain));
} else 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(S, BB, BinOp->getOperand(0), TI, L, Domain,
InvalidDomainMap, ConditionSets) &&
buildConditionSets(S, BB, BinOp->getOperand(1), TI, L, Domain,
InvalidDomainMap, 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!");
LoopInfo &LI = *S.getLI();
DominatorTree &DT = *S.getDT();
Region &R = S.getRegion();
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();
const SCEV *LeftOperand = SE.getSCEVAtScope(ICond->getOperand(0), L),
*RightOperand = SE.getSCEVAtScope(ICond->getOperand(1), L);
LeftOperand = tryForwardThroughPHI(LeftOperand, R, SE, LI, DT);
RightOperand = tryForwardThroughPHI(RightOperand, R, SE, LI, DT);
switch (ICond->getPredicate()) {
case ICmpInst::ICMP_ULT:
ConsequenceCondSet =
buildUnsignedConditionSets(S, BB, Condition, Domain, LeftOperand,
RightOperand, InvalidDomainMap, true);
break;
case ICmpInst::ICMP_ULE:
ConsequenceCondSet =
buildUnsignedConditionSets(S, BB, Condition, Domain, LeftOperand,
RightOperand, InvalidDomainMap, false);
break;
case ICmpInst::ICMP_UGT:
ConsequenceCondSet =
buildUnsignedConditionSets(S, BB, Condition, Domain, RightOperand,
LeftOperand, InvalidDomainMap, true);
break;
case ICmpInst::ICMP_UGE:
ConsequenceCondSet =
buildUnsignedConditionSets(S, BB, Condition, Domain, RightOperand,
LeftOperand, InvalidDomainMap, false);
break;
default:
LHS = getPwAff(S, BB, InvalidDomainMap, LeftOperand, NonNeg);
RHS = getPwAff(S, BB, InvalidDomainMap, RightOperand, NonNeg);
ConsequenceCondSet = buildConditionSet(ICond->getPredicate(), LHS, RHS);
break;
}
}
// 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) >= MaxDisjunctsInDomain;
if (!TooComplex) {
AlternativeCondSet = isl_set_subtract(isl_set_copy(Domain),
isl_set_copy(ConsequenceCondSet));
TooComplex =
isl_set_n_basic_set(AlternativeCondSet) >= MaxDisjunctsInDomain;
}
if (TooComplex) {
S.invalidate(COMPLEXITY, TI ? TI->getDebugLoc() : DebugLoc(),
TI ? TI->getParent() : nullptr /* BasicBlock */);
isl_set_free(AlternativeCondSet);
isl_set_free(ConsequenceCondSet);
return false;
}
ConditionSets.push_back(ConsequenceCondSet);
ConditionSets.push_back(isl_set_coalesce(AlternativeCondSet));
return true;
}
/// 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.
bool buildConditionSets(Scop &S, BasicBlock *BB, TerminatorInst *TI, Loop *L,
__isl_keep isl_set *Domain,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
if (SwitchInst *SI = dyn_cast<SwitchInst>(TI))
return buildConditionSets(S, BB, SI, L, Domain, InvalidDomainMap,
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(S, BB, Condition, TI, L, Domain, InvalidDomainMap,
ConditionSets);
}
ScopStmt::ScopStmt(Scop &parent, Region &R, StringRef Name,
Loop *SurroundingLoop,
std::vector<Instruction *> EntryBlockInstructions)
: Parent(parent), InvalidDomain(nullptr), Domain(nullptr), R(&R),
Build(nullptr), BaseName(Name), SurroundingLoop(SurroundingLoop),
Instructions(EntryBlockInstructions) {}
ScopStmt::ScopStmt(Scop &parent, BasicBlock &bb, StringRef Name,
Loop *SurroundingLoop,
std::vector<Instruction *> Instructions)
: Parent(parent), InvalidDomain(nullptr), Domain(nullptr), BB(&bb),
Build(nullptr), BaseName(Name), SurroundingLoop(SurroundingLoop),
Instructions(Instructions) {}
ScopStmt::ScopStmt(Scop &parent, isl::map SourceRel, isl::map TargetRel,
isl::set NewDomain)
: Parent(parent), InvalidDomain(nullptr), Domain(NewDomain),
Build(nullptr) {
BaseName = getIslCompatibleName("CopyStmt_", "",
std::to_string(parent.getCopyStmtsNum()));
isl::id Id = isl::id::alloc(getIslCtx(), getBaseName(), this);
Domain = Domain.set_tuple_id(Id);
TargetRel = TargetRel.set_tuple_id(isl::dim::in, Id);
auto *Access =
new MemoryAccess(this, MemoryAccess::AccessType::MUST_WRITE, TargetRel);
parent.addAccessFunction(Access);
addAccess(Access);
SourceRel = SourceRel.set_tuple_id(isl::dim::in, Id);
Access = new MemoryAccess(this, MemoryAccess::AccessType::READ, SourceRel);
parent.addAccessFunction(Access);
addAccess(Access);
}
ScopStmt::~ScopStmt() = default;
std::string ScopStmt::getDomainStr() const { return Domain.to_str(); }
std::string ScopStmt::getScheduleStr() const {
auto *S = getSchedule().release();
if (!S)
return {};
auto Str = stringFromIslObj(S);
isl_map_free(S);
return Str;
}
void ScopStmt::setInvalidDomain(isl::set ID) { 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::set ScopStmt::getDomain() const { return Domain; }
isl::space ScopStmt::getDomainSpace() const { return Domain.get_space(); }
isl::id ScopStmt::getDomainId() const { return Domain.get_tuple_id(); }
void ScopStmt::printInstructions(raw_ostream &OS) const {
OS << "Instructions {\n";
for (Instruction *Inst : Instructions)
OS.indent(16) << *Inst << "\n";
OS.indent(12) << "}\n";
}
void ScopStmt::print(raw_ostream &OS, bool PrintInstructions) 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);
if (PrintInstructions)
printInstructions(OS.indent(12));
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void ScopStmt::dump() const { print(dbgs(), true); }
#endif
void ScopStmt::removeAccessData(MemoryAccess *MA) {
if (MA->isRead() && MA->isOriginalValueKind()) {
bool Found = ValueReads.erase(MA->getAccessValue());
(void)Found;
assert(Found && "Expected access data not found");
}
if (MA->isWrite() && MA->isOriginalValueKind()) {
bool Found = ValueWrites.erase(cast<Instruction>(MA->getAccessValue()));
(void)Found;
assert(Found && "Expected access data not found");
}
if (MA->isWrite() && MA->isOriginalAnyPHIKind()) {
bool Found = PHIWrites.erase(cast<PHINode>(MA->getAccessInstruction()));
(void)Found;
assert(Found && "Expected access data not found");
}
if (MA->isRead() && MA->isOriginalAnyPHIKind()) {
bool Found = PHIReads.erase(cast<PHINode>(MA->getAccessInstruction()));
(void)Found;
assert(Found && "Expected access data not found");
}
}
void ScopStmt::removeMemoryAccess(MemoryAccess *MA) {
// Remove the memory accesses from this statement together with all scalar
// accesses that were caused by it. MemoryKind::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 MemoryKind::Value READ
// accesses to be removed.
auto Predicate = [&](MemoryAccess *Acc) {
return Acc->getAccessInstruction() == MA->getAccessInstruction();
};
for (auto *MA : MemAccs) {
if (Predicate(MA)) {
removeAccessData(MA);
Parent.removeAccessData(MA);
}
}
MemAccs.erase(std::remove_if(MemAccs.begin(), MemAccs.end(), Predicate),
MemAccs.end());
InstructionToAccess.erase(MA->getAccessInstruction());
}
void ScopStmt::removeSingleMemoryAccess(MemoryAccess *MA) {
auto MAIt = std::find(MemAccs.begin(), MemAccs.end(), MA);
assert(MAIt != MemAccs.end());
MemAccs.erase(MAIt);
removeAccessData(MA);
Parent.removeAccessData(MA);
auto It = InstructionToAccess.find(MA->getAccessInstruction());
if (It != InstructionToAccess.end()) {
It->second.remove(MA);
if (It->second.empty())
InstructionToAccess.erase(MA->getAccessInstruction());
}
}
MemoryAccess *ScopStmt::ensureValueRead(Value *V) {
MemoryAccess *Access = lookupInputAccessOf(V);
if (Access)
return Access;
ScopArrayInfo *SAI =
Parent.getOrCreateScopArrayInfo(V, V->getType(), {}, MemoryKind::Value);
Access = new MemoryAccess(this, nullptr, MemoryAccess::READ, V, V->getType(),
true, {}, {}, V, MemoryKind::Value);
Parent.addAccessFunction(Access);
Access->buildAccessRelation(SAI);
addAccess(Access);
Parent.addAccessData(Access);
return Access;
}
raw_ostream &polly::operator<<(raw_ostream &OS, const ScopStmt &S) {
S.print(OS, PollyPrintInstructions);
return OS;
}
//===----------------------------------------------------------------------===//
/// Scop class implement
void Scop::setContext(isl::set NewContext) {
Context = NewContext.align_params(Context.get_space());
}
namespace {
/// Remap parameter values but keep AddRecs valid wrt. invariant loads.
struct SCEVSensitiveParameterRewriter
: public SCEVRewriteVisitor<SCEVSensitiveParameterRewriter> {
const ValueToValueMap &VMap;
public:
SCEVSensitiveParameterRewriter(const ValueToValueMap &VMap,
ScalarEvolution &SE)
: SCEVRewriteVisitor(SE), VMap(VMap) {}
static const SCEV *rewrite(const SCEV *E, ScalarEvolution &SE,
const ValueToValueMap &VMap) {
SCEVSensitiveParameterRewriter SSPR(VMap, SE);
return SSPR.visit(E);
}
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;
}
};
/// Check whether we should remap a SCEV expression.
struct SCEVFindInsideScop : public SCEVTraversal<SCEVFindInsideScop> {
const ValueToValueMap &VMap;
bool FoundInside = false;
const Scop *S;
public:
SCEVFindInsideScop(const ValueToValueMap &VMap, ScalarEvolution &SE,
const Scop *S)
: SCEVTraversal(*this), VMap(VMap), S(S) {}
static bool hasVariant(const SCEV *E, ScalarEvolution &SE,
const ValueToValueMap &VMap, const Scop *S) {
SCEVFindInsideScop SFIS(VMap, SE, S);
SFIS.visitAll(E);
return SFIS.FoundInside;
}
bool follow(const SCEV *E) {
if (auto *AddRec = dyn_cast<SCEVAddRecExpr>(E)) {
FoundInside |= S->getRegion().contains(AddRec->getLoop());
} else if (auto *Unknown = dyn_cast<SCEVUnknown>(E)) {
if (Instruction *I = dyn_cast<Instruction>(Unknown->getValue()))
FoundInside |= S->getRegion().contains(I) && !VMap.count(I);
}
return !FoundInside;
}
bool isDone() { return FoundInside; }
};
} // end anonymous namespace
const SCEV *Scop::getRepresentingInvariantLoadSCEV(const SCEV *E) const {
// Check whether it makes sense to rewrite the SCEV. (ScalarEvolution
// doesn't like addition between an AddRec and an expression that
// doesn't have a dominance relationship with it.)
if (SCEVFindInsideScop::hasVariant(E, *SE, InvEquivClassVMap, this))
return E;
// Rewrite SCEV.
return SCEVSensitiveParameterRewriter::rewrite(E, *SE, InvEquivClassVMap);
}
// This table of function names is used to translate parameter names in more
// human-readable names. This makes it easier to interpret Polly analysis
// results.
StringMap<std::string> KnownNames = {
{"_Z13get_global_idj", "global_id"},
{"_Z12get_local_idj", "local_id"},
{"_Z15get_global_sizej", "global_size"},
{"_Z14get_local_sizej", "local_size"},
{"_Z12get_work_dimv", "work_dim"},
{"_Z17get_global_offsetj", "global_offset"},
{"_Z12get_group_idj", "group_id"},
{"_Z14get_num_groupsj", "num_groups"},
};
static std::string getCallParamName(CallInst *Call) {
std::string Result;
raw_string_ostream OS(Result);
std::string Name = Call->getCalledFunction()->getName();
auto Iterator = KnownNames.find(Name);
if (Iterator != KnownNames.end())
Name = "__" + Iterator->getValue();
OS << Name;
for (auto &Operand : Call->arg_operands()) {
ConstantInt *Op = cast<ConstantInt>(&Operand);
OS << "_" << Op->getValue();
}
OS.flush();
return Result;
}
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();
CallInst *Call = dyn_cast<CallInst>(Val);
if (Call && isConstCall(Call)) {
ParameterName = getCallParamName(Call);
} else if (UseInstructionNames) {
// 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, "");
}
isl::id Id = isl::id::alloc(getIslCtx(), ParameterName,
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::id Scop::getIdForParam(const SCEV *Parameter) const {
// Normalize the SCEV to get the representing element for an invariant load.
Parameter = getRepresentingInvariantLoadSCEV(Parameter);
return ParameterIds.lookup(Parameter);
}
isl::set Scop::addNonEmptyDomainConstraints(isl::set C) const {
isl_set *DomainContext = isl_union_set_params(getDomains().release());
return isl::manage(isl_set_intersect_params(C.release(), DomainContext));
}
bool Scop::isDominatedBy(const DominatorTree &DT, BasicBlock *BB) const {
return DT.dominates(BB, getEntry());
}
void Scop::addUserAssumptions(
AssumptionCache &AC, DominatorTree &DT, LoopInfo &LI,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap) {
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)) {
ORE.emit(
OptimizationRemarkAnalysis(DEBUG_TYPE, "IgnoreUserAssumption", CI)
<< "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;
BasicBlock *BB = InScop ? CI->getParent() : getRegion().getEntry();
auto *Dom = InScop ? DomainMap[BB].copy() : Context.copy();
assert(Dom && "Cannot propagate a nullptr.");
bool Valid = buildConditionSets(*this, BB, Val, TI, L, Dom,
InvalidDomainMap, 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);
}
}
ORE.emit(OptimizationRemarkAnalysis(DEBUG_TYPE, "UserAssumption", CI)
<< "Use user assumption: " << stringFromIslObj(AssumptionCtx));
Context = Context.intersect(isl::manage(AssumptionCtx));
}
}
void Scop::addUserContext() {
if (UserContextStr.empty())
return;
isl_set *UserContext =
isl_set_read_from_str(getIslCtx().get(), UserContextStr.c_str());
isl_space *Space = getParamSpace().release();
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++) {
std::string NameContext = Context.get_dim_name(isl::dim::param, i);
std::string NameUserContext =
isl_set_get_dim_name(UserContext, isl_dim_param, i);
if (NameContext != NameUserContext) {
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 = Context.intersect(isl::manage(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(
InvariantEquivClassTy{PointerSCEV, MemoryAccessList(), nullptr, Ty});
}
}
void Scop::buildContext() {
isl::space Space = isl::space::params_alloc(getIslCtx(), 0);
Context = isl::set::universe(Space);
InvalidContext = isl::set::empty(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);
}
}
static std::vector<isl::id> getFortranArrayIds(Scop::array_range Arrays) {
std::vector<isl::id> OutermostSizeIds;
for (auto Array : Arrays) {
// To check if an array is a Fortran array, we check if it has a isl_pw_aff
// for its outermost dimension. Fortran arrays will have this since the
// outermost dimension size can be picked up from their runtime description.
// TODO: actually need to check if it has a FAD, but for now this works.
if (Array->getNumberOfDimensions() > 0) {
isl::pw_aff PwAff = Array->getDimensionSizePw(0);
if (!PwAff)
continue;
isl::id Id =
isl::manage(isl_pw_aff_get_dim_id(PwAff.get(), isl_dim_param, 0));
assert(!Id.is_null() &&
"Invalid Id for PwAff expression in Fortran array");
Id.dump();
OutermostSizeIds.push_back(Id);
}
}
return OutermostSizeIds;
}
// The FORTRAN array size parameters are known to be non-negative.
static isl::set boundFortranArrayParams(isl::set Context,
Scop::array_range Arrays) {
std::vector<isl::id> OutermostSizeIds;
OutermostSizeIds = getFortranArrayIds(Arrays);
for (isl::id Id : OutermostSizeIds) {
int dim = Context.find_dim_by_id(isl::dim::param, Id);
Context = Context.lower_bound_si(isl::dim::param, dim, 0);
}
return Context;
}
void Scop::realignParams() {
if (PollyIgnoreParamBounds)
return;
// Add all parameters into a common model.
isl::space Space = getFullParamSpace();
// Align the parameters of all data structures to the model.
Context = Context.align_params(Space);
// Bound the size of the fortran array dimensions.
Context = boundFortranArrayParams(Context, arrays());
// 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 = Schedule.gist_domain_params(getContext());
}
static isl::set simplifyAssumptionContext(isl::set AssumptionContext,
const Scop &S) {
// If we have modeled 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 occur and removed them from the
// domains, thus we cannot use the remaining domain to simplify the
// assumptions.
if (!S.hasErrorBlock()) {
auto DomainParameters = S.getDomains().params();
AssumptionContext = AssumptionContext.gist_params(DomainParameters);
}
AssumptionContext = AssumptionContext.gist_params(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 = InvalidContext.align_params(getParamSpace());
}
/// Add the minimal/maximal access in @p Set to @p User.
static isl::stat
buildMinMaxAccess(isl::set Set, Scop::MinMaxVectorTy &MinMaxAccesses, Scop &S) {
isl::pw_multi_aff MinPMA, MaxPMA;
isl::pw_aff LastDimAff;
isl::aff OneAff;
unsigned Pos;
isl::ctx Ctx = Set.get_ctx();
Set = Set.remove_divs();
if (isl_set_n_basic_set(Set.get()) >= MaxDisjunctsInDomain)
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.get()) > RunTimeChecksMaxParameters) {
unsigned InvolvedParams = 0;
for (unsigned u = 0, e = isl_set_n_param(Set.get()); u < e; u++)
if (Set.involves_dims(isl::dim::param, u, 1))
InvolvedParams++;
if (InvolvedParams > RunTimeChecksMaxParameters)
return isl::stat::error;
}
if (isl_set_n_basic_set(Set.get()) > RunTimeChecksMaxAccessDisjuncts)
return isl::stat::error;
MinPMA = Set.lexmin_pw_multi_aff();
MaxPMA = Set.lexmax_pw_multi_aff();
if (isl_ctx_last_error(Ctx.get()) == isl_error_quota)
return isl::stat::error;
MinPMA = MinPMA.coalesce();
MaxPMA = MaxPMA.coalesce();
// 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(MaxPMA.dim(isl::dim::out) && "Assumed at least one output dimension");
Pos = MaxPMA.dim(isl::dim::out) - 1;
LastDimAff = MaxPMA.get_pw_aff(Pos);
OneAff = isl::aff(isl::local_space(LastDimAff.get_domain_space()));
OneAff = OneAff.add_constant_si(1);
LastDimAff = LastDimAff.add(OneAff);
MaxPMA = MaxPMA.set_pw_aff(Pos, LastDimAff);
MinMaxAccesses.push_back(std::make_pair(MinPMA, MaxPMA));
return isl::stat::ok;
}
static __isl_give isl_set *getAccessDomain(MemoryAccess *MA) {
isl_set *Domain = MA->getStatement()->getDomain().release();
Domain = isl_set_project_out(Domain, isl_dim_set, 0, isl_set_n_dim(Domain));
return isl_set_reset_tuple_id(Domain);
}
/// Wrapper function to calculate minimal/maximal accesses to each array.
static bool calculateMinMaxAccess(Scop::AliasGroupTy AliasGroup, Scop &S,
Scop::MinMaxVectorTy &MinMaxAccesses) {
MinMaxAccesses.reserve(AliasGroup.size());
isl::union_set Domains = S.getDomains();
isl::union_map Accesses = isl::union_map::empty(S.getParamSpace());
for (MemoryAccess *MA : AliasGroup)
Accesses = Accesses.add_map(give(MA->getAccessRelation().release()));
Accesses = Accesses.intersect_domain(Domains);
isl::union_set Locations = Accesses.range();
Locations = Locations.coalesce();
Locations = Locations.detect_equalities();
auto Lambda = [&MinMaxAccesses, &S](isl::set Set) -> isl::stat {
return buildMinMaxAccess(Set, MinMaxAccesses, S);
};
return Locations.foreach_set(Lambda) == isl::stat::ok;
}
/// Helper to treat non-affine regions and basic blocks the same.
///
///{
/// 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>();
}
/// 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);
}
/// Return the smallest loop surrounding @p RN.
static inline Loop *getRegionNodeLoop(RegionNode *RN, LoopInfo &LI) {
if (!RN->isSubRegion()) {
BasicBlock *BB = RN->getNodeAs<BasicBlock>();
Loop *L = LI.getLoopFor(BB);
// Unreachable statements are not considered to belong to a LLVM loop, as
// they are not part of an actual loop in the control flow graph.
// Nevertheless, we handle certain unreachable statements that are common
// when modeling run-time bounds checks as being part of the loop to be
// able to model them and to later eliminate the run-time bounds checks.
//
// Specifically, for basic blocks that terminate in an unreachable and
// where the immediate predecessor is part of a loop, we assume these
// basic blocks belong to the loop the predecessor belongs to. This
// allows us to model the following code.
//
// for (i = 0; i < N; i++) {
// if (i > 1024)
// abort(); <- this abort might be translated to an
// unreachable
//
// A[i] = ...
// }
if (!L && isa<UnreachableInst>(BB->getTerminator()) && BB->getPrevNode())
L = LI.getLoopFor(BB->getPrevNode());
return L;
}
Region *NonAffineSubRegion = RN->getNodeAs<Region>();
Loop *L = LI.getLoopFor(NonAffineSubRegion->getEntry());
while (L && NonAffineSubRegion->contains(L))
L = L->getParentLoop();
return L;
}
/// Get the number of blocks in @p L.
///
/// The number of blocks in a loop are the number of basic blocks actually
/// belonging to the loop, as well as all single basic blocks that the loop
/// exits to and which terminate in an unreachable instruction. We do not
/// allow such basic blocks in the exit of a scop, hence they belong to the
/// scop and represent run-time conditions which we want to model and
/// subsequently speculate away.
///
/// @see getRegionNodeLoop for additional details.
unsigned getNumBlocksInLoop(Loop *L) {
unsigned NumBlocks = L->getNumBlocks();
SmallVector<BasicBlock *, 4> ExitBlocks;
L->getExitBlocks(ExitBlocks);
for (auto ExitBlock : ExitBlocks) {
if (isa<UnreachableInst>(ExitBlock->getTerminator()))
NumBlocks++;
}
return NumBlocks;
}
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;
}
///}
isl::set Scop::getDomainConditions(const ScopStmt *Stmt) const {
return getDomainConditions(Stmt->getEntryBlock());
}
isl::set Scop::getDomainConditions(BasicBlock *BB) const {
auto DIt = DomainMap.find(BB);
if (DIt != DomainMap.end())
return 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,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap) {
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().get(), 0, LD + 1));
while (LD-- >= 0) {
L = L->getParentLoop();
}
InvalidDomainMap[EntryBB] = isl::manage(isl_set_empty(isl_set_get_space(S)));
DomainMap[EntryBB] = isl::manage(S);
if (IsOnlyNonAffineRegion)
return !containsErrorBlock(R->getNode(), *R, LI, DT);
if (!buildDomainsWithBranchConstraints(R, DT, LI, InvalidDomainMap))
return false;
if (!propagateDomainConstraints(R, DT, LI, InvalidDomainMap))
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, InvalidDomainMap))
return false;
return true;
}
/// 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);
} 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);
} 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,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap) {
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, InvalidDomainMap);
continue;
}
}
bool ContainsErrorBlock = containsErrorBlock(RN, getRegion(), LI, DT);
BasicBlock *BB = getRegionNodeBasicBlock(RN);
isl::set &Domain = DomainMap[BB];
assert(Domain && "Cannot propagate a nullptr");
isl::set InvalidDomain = InvalidDomainMap[BB];
bool IsInvalidBlock = ContainsErrorBlock || Domain.is_subset(InvalidDomain);
if (!IsInvalidBlock) {
InvalidDomain = InvalidDomain.intersect(Domain);
} else {
InvalidDomain = Domain;
isl::set DomPar = Domain.params();
recordAssumption(ERRORBLOCK, DomPar, BB->getTerminator()->getDebugLoc(),
AS_RESTRICTION);
Domain = nullptr;
}
if (InvalidDomain.is_empty()) {
InvalidDomainMap[BB] = 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);
// Skip successors outside the SCoP.
if (!contains(SuccBB))
continue;
// Skip backedges.
if (DT.dominates(SuccBB, BB))
continue;
Loop *SuccBBLoop = getFirstNonBoxedLoopFor(SuccBB, LI, getBoxedLoops());
auto *AdjustedInvalidDomain = adjustDomainDimensions(
*this, InvalidDomain.copy(), BBLoop, SuccBBLoop);
auto *SuccInvalidDomain = InvalidDomainMap[SuccBB].copy();
SuccInvalidDomain =
isl_set_union(SuccInvalidDomain, AdjustedInvalidDomain);
SuccInvalidDomain = isl_set_coalesce(SuccInvalidDomain);
unsigned NumConjucts = isl_set_n_basic_set(SuccInvalidDomain);
InvalidDomainMap[SuccBB] = isl::manage(SuccInvalidDomain);
// Check if the maximal number of domain disjunctions was reached.
// In case this happens we will bail.
if (NumConjucts < MaxDisjunctsInDomain)
continue;
InvalidDomainMap.erase(BB);
invalidate(COMPLEXITY, TI->getDebugLoc(), TI->getParent());
return false;
}
InvalidDomainMap[BB] = InvalidDomain;
}
return true;
}
void Scop::propagateDomainConstraintsToRegionExit(
BasicBlock *BB, Loop *BBLoop,
SmallPtrSetImpl<BasicBlock *> &FinishedExitBlocks, LoopInfo &LI,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap) {
// 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;
// Do not propagate the domain if there is a loop backedge inside the region
// that would prevent the exit block from being 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();
}
isl::set Domain = DomainMap[BB];
assert(Domain && "Cannot propagate a nullptr");
Loop *ExitBBLoop = getFirstNonBoxedLoopFor(ExitBB, LI, getBoxedLoops());
// Since the dimensions of @p BB and @p ExitBB might be different we have to
// adjust the domain before we can propagate it.
isl::set AdjustedDomain = isl::manage(
adjustDomainDimensions(*this, Domain.copy(), BBLoop, ExitBBLoop));
isl::set &ExitDomain = DomainMap[ExitBB];
// If the exit domain is not yet created we set it otherwise we "add" the
// current domain.
ExitDomain = ExitDomain ? AdjustedDomain.unite(ExitDomain) : AdjustedDomain;
// Initialize the invalid domain.
InvalidDomainMap[ExitBB] = ExitDomain.empty(ExitDomain.get_space());
FinishedExitBlocks.insert(ExitBB);
}
bool Scop::buildDomainsWithBranchConstraints(
Region *R, DominatorTree &DT, LoopInfo &LI,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap) {
// 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,
InvalidDomainMap))
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.get()));
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,
InvalidDomainMap);
// 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(Domain.copy());
else if (!buildConditionSets(*this, BB, TI, BBLoop, Domain.get(),
InvalidDomainMap, 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 = isl::manage(ConditionSets[u]);
BasicBlock *SuccBB = getRegionNodeSuccessor(RN, TI, u);
// Skip blocks outside the region.
if (!contains(SuccBB))
continue;
// If we propagate the domain of some block to "SuccBB" we do not have to
// adjust the domain.
if (FinishedExitBlocks.count(SuccBB))
continue;
// Skip back edges.
if (DT.dominates(SuccBB, BB))
continue;
Loop *SuccBBLoop = getFirstNonBoxedLoopFor(SuccBB, LI, getBoxedLoops());
CondSet = isl::manage(
adjustDomainDimensions(*this, CondSet.copy(), 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 = SuccDomain.unite(CondSet).coalesce();
} else {
// Initialize the invalid domain.
InvalidDomainMap[SuccBB] = CondSet.empty(CondSet.get_space());
SuccDomain = CondSet;
}
SuccDomain = SuccDomain.detect_equalities();
// 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.get()) < MaxDisjunctsInDomain)
continue;
invalidate(COMPLEXITY, DebugLoc());
while (++u < ConditionSets.size())
isl_set_free(ConditionSets[u]);
return false;
}
}
return true;
}
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(Domain.get_space());
// The region info of this function.
auto &RI = *R.getRegionInfo();
Loop *BBLoop = getFirstNonBoxedLoopFor(BB, LI, getBoxedLoops());
// 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(Domain.get_space());
// 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).release();
Loop *PredBBLoop = getFirstNonBoxedLoopFor(PredBB, LI, getBoxedLoops());
PredBBDom = adjustDomainDimensions(*this, PredBBDom, PredBBLoop, BBLoop);
PredDom = PredDom.unite(isl::manage(PredBBDom));
}
return PredDom;
}
bool Scop::propagateDomainConstraints(
Region *R, DominatorTree &DT, LoopInfo &LI,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap) {
// 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, InvalidDomainMap))
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.
isl::set PredDom = getPredecessorDomainConstraints(BB, Domain, DT, LI);
Domain = Domain.intersect(PredDom).coalesce();
Domain = Domain.align_params(getParamSpace());
Loop *BBLoop = getRegionNodeLoop(RN, LI);
if (BBLoop && BBLoop->getHeader() == BB && contains(BBLoop))
if (!addLoopBoundsToHeaderDomain(BBLoop, LI, InvalidDomainMap))
return false;
}
return true;
}
/// Create a map to map from a given iteration to a subsequent iteration.
///
/// This map maps 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_dim(NextIterationMap, isl_dim_in); 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, DenseMap<BasicBlock *, isl::set> &InvalidDomainMap) {
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 = isl::manage(
createNextIterationMap(HeaderBBDom.get_space().release(), LoopDepth));
isl::set UnionBackedgeCondition = HeaderBBDom.empty(HeaderBBDom.get_space());
SmallVector<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);
assert(BI && "Only branch instructions allowed in loop latches");
if (BI->isUnconditional())
BackedgeCondition = LatchBBDom;
else {
SmallVector<isl_set *, 8> ConditionSets;
int idx = BI->getSuccessor(0) != HeaderBB;
if (!buildConditionSets(*this, LatchBB, TI, L, LatchBBDom.get(),
InvalidDomainMap, ConditionSets))
return false;
// Free the non back edge condition set as we do not need it.
isl_set_free(ConditionSets[1 - idx]);
BackedgeCondition = isl::manage(ConditionSets[idx]);
}
int LatchLoopDepth = getRelativeLoopDepth(LI.getLoopFor(LatchBB));
assert(LatchLoopDepth >= LoopDepth);
BackedgeCondition = BackedgeCondition.project_out(
isl::dim::set, LoopDepth + 1, LatchLoopDepth - LoopDepth);
UnionBackedgeCondition = UnionBackedgeCondition.unite(BackedgeCondition);
}
isl::map ForwardMap = ForwardMap.lex_le(HeaderBBDom.get_space());
for (int i = 0; i < LoopDepth; i++)
ForwardMap = ForwardMap.equate(isl::dim::in, i, isl::dim::out, i);
isl::set UnionBackedgeConditionComplement =
UnionBackedgeCondition.complement();
UnionBackedgeConditionComplement =
UnionBackedgeConditionComplement.lower_bound_si(isl::dim::set, LoopDepth,
0);
UnionBackedgeConditionComplement =
UnionBackedgeConditionComplement.apply(ForwardMap);
HeaderBBDom = HeaderBBDom.subtract(UnionBackedgeConditionComplement);
HeaderBBDom = HeaderBBDom.apply(NextIterationMap);
auto Parts = partitionSetParts(HeaderBBDom.copy(), LoopDepth);
HeaderBBDom = isl::manage(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::manage(Parts.first).params();
recordAssumption(INFINITELOOP, UnboundedCtx,
HeaderBB->getTerminator()->getDebugLoc(), AS_RESTRICTION);
return true;
}
MemoryAccess *Scop::lookupBasePtrAccess(MemoryAccess *MA) {
Value *PointerBase = MA->getOriginalBaseAddr();
auto *PointerBaseInst = dyn_cast<Instruction>(PointerBase);
if (!PointerBaseInst)
return nullptr;
auto *BasePtrStmt = getStmtFor(PointerBaseInst);
if (!BasePtrStmt)
return nullptr;
return BasePtrStmt->getArrayAccessOrNULLFor(PointerBaseInst);
}
bool Scop::hasNonHoistableBasePtrInScop(MemoryAccess *MA,
isl::union_map Writes) {
if (auto *BasePtrMA = lookupBasePtrAccess(MA)) {
return getNonHoistableCtx(BasePtrMA, Writes).is_null();
}
Value *BaseAddr = MA->getOriginalBaseAddr();
if (auto *BasePtrInst = dyn_cast<Instruction>(BaseAddr))
if (!isa<LoadInst>(BasePtrInst))
return contains(BasePtrInst);
return false;
}
bool Scop::buildAliasChecks(AliasAnalysis &AA) {
if (!PollyUseRuntimeAliasChecks)
return true;
if (buildAliasGroups(AA)) {
// Aliasing assumptions do not go through addAssumption but we still want to
// collect statistics so we do it here explicitly.
if (MinMaxAliasGroups.size())
AssumptionsAliasing++;
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;
}
std::tuple<Scop::AliasGroupVectorTy, DenseSet<const ScopArrayInfo *>>
Scop::buildAliasGroupsForAccesses(AliasAnalysis &AA) {
AliasSetTracker AST(AA);
DenseMap<Value *, MemoryAccess *> PtrToAcc;
DenseSet<const ScopArrayInfo *> HasWriteAccess;
for (ScopStmt &Stmt : *this) {
isl_set *StmtDomain = Stmt.getDomain().release();
bool StmtDomainEmpty = isl_set_is_empty(StmtDomain);
isl_set_free(StmtDomain);
// Statements with an empty domain will never be executed.
if (StmtDomainEmpty)
continue;
for (MemoryAccess *MA : Stmt) {
if (MA->isScalarKind())
continue;
if (!MA->isRead())
HasWriteAccess.insert(MA->getScopArrayInfo());
MemAccInst Acc(MA->getAccessInstruction());
if (MA->isRead() && isa<MemTransferInst>(Acc))
PtrToAcc[cast<MemTransferInst>(Acc)->getRawSource()] = MA;
else
PtrToAcc[Acc.getPointerOperand()] = MA;
AST.add(Acc);
}
}
AliasGroupVectorTy 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));
}
return std::make_tuple(AliasGroups, HasWriteAccess);
}
void Scop::splitAliasGroupsByDomain(AliasGroupVectorTy &AliasGroups) {
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);
}
}
bool Scop::buildAliasGroups(AliasAnalysis &AA) {
// To create sound alias checks we perform the following steps:
// 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.
AliasGroupVectorTy AliasGroups;
DenseSet<const ScopArrayInfo *> HasWriteAccess;
std::tie(AliasGroups, HasWriteAccess) = buildAliasGroupsForAccesses(AA);
splitAliasGroupsByDomain(AliasGroups);
for (AliasGroupTy &AG : AliasGroups) {
if (!hasFeasibleRuntimeContext())
return false;
{
IslMaxOperationsGuard MaxOpGuard(getIslCtx().get(), OptComputeOut);
bool Valid = buildAliasGroup(AG, HasWriteAccess);
if (!Valid)
return false;
}
if (isl_ctx_last_error(getIslCtx().get()) == isl_error_quota) {
invalidate(COMPLEXITY, DebugLoc());
return false;
}
}
return true;
}
bool Scop::buildAliasGroup(Scop::AliasGroupTy &AliasGroup,
DenseSet<const ScopArrayInfo *> HasWriteAccess) {
AliasGroupTy ReadOnlyAccesses;
AliasGroupTy ReadWriteAccesses;
SmallPtrSet<const ScopArrayInfo *, 4> ReadWriteArrays;
SmallPtrSet<const ScopArrayInfo *, 4> ReadOnlyArrays;
if (AliasGroup.size() < 2)
return true;
for (MemoryAccess *Access : AliasGroup) {
ORE.emit(OptimizationRemarkAnalysis(DEBUG_TYPE, "PossibleAlias",
Access->getAccessInstruction())
<< "Possibly aliasing pointer, use restrict keyword.");
const ScopArrayInfo *Array = Access->getScopArrayInfo();
if (HasWriteAccess.count(Array)) {
ReadWriteArrays.insert(Array);
ReadWriteAccesses.push_back(Access);
} else {
ReadOnlyArrays.insert(Array);
ReadOnlyAccesses.push_back(Access);
}
}
// If there are no read-only pointers, and less than two read-write pointers,
// no alias check is needed.
if (ReadOnlyAccesses.empty() && ReadWriteArrays.size() <= 1)
return true;
// If there is no read-write pointer, no alias check is needed.
if (ReadWriteArrays.empty())
return true;
// For non-affine accesses, no alias check can be generated as we cannot
// compute a sufficiently tight lower and upper bound: bail out.
for (MemoryAccess *MA : AliasGroup) {
if (!MA->isAffine()) {
invalidate(ALIASING, MA->getAccessInstruction()->getDebugLoc(),
MA->getAccessInstruction()->getParent());
return false;
}
}
// Ensure that for all memory accesses for which we generate alias checks,
// their base pointers are available.
for (MemoryAccess *MA : AliasGroup) {
if (MemoryAccess *BasePtrMA = lookupBasePtrAccess(MA))
addRequiredInvariantLoad(
cast<LoadInst>(BasePtrMA->getAccessInstruction()));
}
MinMaxAliasGroups.emplace_back();
MinMaxVectorPairTy &pair = MinMaxAliasGroups.back();
MinMaxVectorTy &MinMaxAccessesReadWrite = pair.first;
MinMaxVectorTy &MinMaxAccessesReadOnly = pair.second;
bool Valid;
Valid =
calculateMinMaxAccess(ReadWriteAccesses, *this, MinMaxAccessesReadWrite);
if (!Valid)
return false;
// Bail out if the number of values we need to compare is too large.
// This is important as the number of comparisons grows quadratically with
// the number of values we need to compare.
if (MinMaxAccessesReadWrite.size() + ReadOnlyArrays.size() >
RunTimeChecksMaxArraysPerGroup)
return false;
Valid =
calculateMinMaxAccess(ReadOnlyAccesses, *this, MinMaxAccessesReadOnly);
if (!Valid)
return false;
return true;
}
/// 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;
}
int Scop::NextScopID = 0;
std::string Scop::CurrentFunc;
int Scop::getNextID(std::string ParentFunc) {
if (ParentFunc != CurrentFunc) {
CurrentFunc = ParentFunc;
NextScopID = 0;
}
return NextScopID++;
}
Scop::Scop(Region &R, ScalarEvolution &ScalarEvolution, LoopInfo &LI,
DominatorTree &DT, ScopDetection::DetectionContext &DC,
OptimizationRemarkEmitter &ORE)
: IslCtx(isl_ctx_alloc(), isl_ctx_free), SE(&ScalarEvolution), DT(&DT),
R(R), name(R.getNameStr()), HasSingleExitEdge(R.getExitingBlock()),
DC(DC), ORE(ORE), Affinator(this, LI),
ID(getNextID((*R.getEntry()->getParent()).getName().str())) {
if (IslOnErrorAbort)
isl_options_set_on_error(getIslCtx().get(), ISL_ON_ERROR_ABORT);
buildContext();
}
Scop::~Scop() = default;
void Scop::foldSizeConstantsToRight() {
isl_union_set *Accessed = isl_union_map_range(getAccesses().release());
for (auto Array : arrays()) {
if (Array->getNumberOfDimensions() <= 1)
continue;
isl_space *Space = Array->getSpace().release();
Space = isl_space_align_params(Space, isl_union_set_get_space(Accessed));
if (!isl_union_set_contains(Accessed, Space)) {
isl_space_free(Space);
continue;
}
isl_set *Elements = isl_union_set_extract_set(Accessed, Space);
isl_map *Transform =
isl_map_universe(isl_space_map_from_set(Array->getSpace().release()));
std::vector<int> Int;
int Dims = isl_set_dim(Elements, isl_dim_set);
for (int i = 0; i < Dims; i++) {
isl_set *DimOnly =
isl_set_project_out(isl_set_copy(Elements), isl_dim_set, 0, i);
DimOnly = isl_set_project_out(DimOnly, isl_dim_set, 1, Dims - i - 1);
DimOnly = isl_set_lower_bound_si(DimOnly, isl_dim_set, 0, 0);
isl_basic_set *DimHull = isl_set_affine_hull(DimOnly);
if (i == Dims - 1) {
Int.push_back(1);
Transform = isl_map_equate(Transform, isl_dim_in, i, isl_dim_out, i);
isl_basic_set_free(DimHull);
continue;
}
if (isl_basic_set_dim(DimHull, isl_dim_div) == 1) {
isl_aff *Diff = isl_basic_set_get_div(DimHull, 0);
isl_val *Val = isl_aff_get_denominator_val(Diff);
isl_aff_free(Diff);
int ValInt = 1;
if (isl_val_is_int(Val)) {
auto ValAPInt = APIntFromVal(Val);
if (ValAPInt.isSignedIntN(32))
ValInt = ValAPInt.getSExtValue();
} else {
isl_val_free(Val);
}
Int.push_back(ValInt);
isl_constraint *C = isl_constraint_alloc_equality(
isl_local_space_from_space(isl_map_get_space(Transform)));
C = isl_constraint_set_coefficient_si(C, isl_dim_out, i, ValInt);
C = isl_constraint_set_coefficient_si(C, isl_dim_in, i, -1);
Transform = isl_map_add_constraint(Transform, C);
isl_basic_set_free(DimHull);
continue;
}
isl_basic_set *ZeroSet = isl_basic_set_copy(DimHull);
ZeroSet = isl_basic_set_fix_si(ZeroSet, isl_dim_set, 0, 0);
int ValInt = 1;
if (isl_basic_set_is_equal(ZeroSet, DimHull)) {
ValInt = 0;
}
Int.push_back(ValInt);
Transform = isl_map_equate(Transform, isl_dim_in, i, isl_dim_out, i);
isl_basic_set_free(DimHull);
isl_basic_set_free(ZeroSet);
}
isl_set *MappedElements = isl_map_domain(isl_map_copy(Transform));
if (!isl_set_is_subset(Elements, MappedElements)) {
isl_set_free(Elements);
isl_set_free(MappedElements);
isl_map_free(Transform);
continue;
}
isl_set_free(MappedElements);
bool CanFold = true;
if (Int[0] <= 1)
CanFold = false;
unsigned NumDims = Array->getNumberOfDimensions();
for (unsigned i = 1; i < NumDims - 1; i++)
if (Int[0] != Int[i] && Int[i])
CanFold = false;
if (!CanFold) {
isl_set_free(Elements);
isl_map_free(Transform);
continue;
}
for (auto &Access : AccessFunctions)
if (Access->getScopArrayInfo() == Array)
Access->setAccessRelation(Access->getAccessRelation().apply_range(
isl::manage_copy(Transform)));
isl_map_free(Transform);
std::vector<const SCEV *> Sizes;
for (unsigned i = 0; i < NumDims; i++) {
auto Size = Array->getDimensionSize(i);
if (i == NumDims - 1)
Size = SE->getMulExpr(Size, SE->getConstant(Size->getType(), Int[0]));
Sizes.push_back(Size);
}
Array->updateSizes(Sizes, false /* CheckConsistency */);
isl_set_free(Elements);
}
isl_union_set_free(Accessed);
}
void Scop::markFortranArrays() {
for (ScopStmt &Stmt : Stmts) {
for (MemoryAccess *MemAcc : Stmt) {
Value *FAD = MemAcc->getFortranArrayDescriptor();
if (!FAD)
continue;
// TODO: const_cast-ing to edit
ScopArrayInfo *SAI =
const_cast<ScopArrayInfo *>(MemAcc->getLatestScopArrayInfo());
assert(SAI && "memory access into a Fortran array does not "
"have an associated ScopArrayInfo");
SAI->applyAndSetFAD(FAD);
}
}
}
void Scop::finalizeAccesses() {
updateAccessDimensionality();
foldSizeConstantsToRight();
foldAccessRelations();
assumeNoOutOfBounds();
markFortranArrays();
}
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 (ScopStmt &Stmt : *this)
for (MemoryAccess *Access : Stmt) {
if (!Access->isArrayKind())
continue;
ScopArrayInfo *Array =
const_cast<ScopArrayInfo *>(Access->getScopArrayInfo());
if (Array->getNumberOfDimensions() != 1)
continue;
unsigned DivisibleSize = Array->getElemSizeInBytes();
const SCEV *Subscript = Access->getSubscript(0);
while (!isDivisible(Subscript, DivisibleSize, *SE))
DivisibleSize /= 2;
auto *Ty = IntegerType::get(SE->getContext(), DivisibleSize * 8);
Array->updateElementType(Ty);
}
for (auto &Stmt : *this)
for (auto &Access : Stmt)
Access->updateDimensionality();
}
void Scop::foldAccessRelations() {
for (auto &Stmt : *this)
for (auto &Access : Stmt)
Access->foldAccessRelation();
}
void Scop::assumeNoOutOfBounds() {
for (auto &Stmt : *this)
for (auto &Access : Stmt)
Access->assumeNoOutOfBound();
}
void Scop::removeFromStmtMap(ScopStmt &Stmt) {
for (Instruction *Inst : Stmt.getInstructions())
InstStmtMap.erase(Inst);
if (Stmt.isRegionStmt()) {
for (BasicBlock *BB : Stmt.getRegion()->blocks()) {
StmtMap.erase(BB);
// Skip entry basic block, as its instructions are already deleted as
// part of the statement's instruction list.
if (BB == Stmt.getEntryBlock())
continue;
for (Instruction &Inst : *BB)
InstStmtMap.erase(&Inst);
}
} else {
auto StmtMapIt = StmtMap.find(Stmt.getBasicBlock());
if (StmtMapIt != StmtMap.end())
StmtMapIt->second.erase(std::remove(StmtMapIt->second.begin(),
StmtMapIt->second.end(), &Stmt),
StmtMapIt->second.end());
for (Instruction *Inst : Stmt.getInstructions())
InstStmtMap.erase(Inst);
}
}
void Scop::removeStmts(std::function<bool(ScopStmt &)> ShouldDelete) {
for (auto StmtIt = Stmts.begin(), StmtEnd = Stmts.end(); StmtIt != StmtEnd;) {
if (!ShouldDelete(*StmtIt)) {
StmtIt++;
continue;
}
removeFromStmtMap(*StmtIt);
StmtIt = Stmts.erase(StmtIt);
}
}
void Scop::removeStmtNotInDomainMap() {
auto ShouldDelete = [this](ScopStmt &Stmt) -> bool {
return !this->DomainMap.lookup(Stmt.getEntryBlock());
};
removeStmts(ShouldDelete);
}
void Scop::simplifySCoP(bool AfterHoisting) {
auto ShouldDelete = [AfterHoisting](ScopStmt &Stmt) -> bool {
bool RemoveStmt = Stmt.isEmpty();
// Remove read only statements only after invariant load hoisting.
if (!RemoveStmt && AfterHoisting) {
bool OnlyRead = true;
for (MemoryAccess *MA : Stmt) {
if (MA->isRead())
continue;
OnlyRead = false;
break;
}
RemoveStmt = OnlyRead;
}
return RemoveStmt;
};
removeStmts(ShouldDelete);
}
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 != IAClass.IdentifyingPointer || Ty != IAClass.AccessType)
continue;
auto &MAs = IAClass.InvariantAccesses;
for (auto *MA : MAs)
if (MA->getAccessInstruction() == Val)
return &IAClass;
}
return nullptr;
}
bool isAParameter(llvm::Value *maybeParam, const Function &F) {
for (const llvm::Argument &Arg : F.args())
if (&Arg == maybeParam)
return true;
return false;
}
bool Scop::canAlwaysBeHoisted(MemoryAccess *MA, bool StmtInvalidCtxIsEmpty,
bool MAInvalidCtxIsEmpty,
bool NonHoistableCtxIsEmpty) {
LoadInst *LInst = cast<LoadInst>(MA->getAccessInstruction());
const DataLayout &DL = LInst->getParent()->getModule()->getDataLayout();
if (PollyAllowDereferenceOfAllFunctionParams &&
isAParameter(LInst->getPointerOperand(), getFunction()))
return true;
// 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 too conservative.
if (!NonHoistableCtxIsEmpty)
return false;
// If a dereferenceable 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 specialized 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;
isl::set StmtInvalidCtx = Stmt.getInvalidContext();
bool StmtInvalidCtxIsEmpty = StmtInvalidCtx.is_empty();
// Get the context under which the statement is executed but remove the error
// context under which this statement is reached.
isl::set DomainCtx = Stmt.getDomain().params();
DomainCtx = DomainCtx.subtract(StmtInvalidCtx);
if (isl_set_n_basic_set(DomainCtx.get()) >= MaxDisjunctsInDomain) {
auto *AccInst = InvMAs.front().MA->getAccessInstruction();
invalidate(COMPLEXITY, AccInst->getDebugLoc(), AccInst->getParent());
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 = DomainCtx.find_dim_by_id(isl::dim::param, ParamId);
if (Dim >= 0)
DomainCtx = DomainCtx.eliminate(isl::dim::param, Dim, 1);
}
}
}
}
for (auto &InvMA : InvMAs) {
auto *MA = InvMA.MA;
isl::set 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());
isl::set MAInvalidCtx = MA->getInvalidContext();
bool NonHoistableCtxIsEmpty = NHCtx.is_empty();
bool MAInvalidCtxIsEmpty = MAInvalidCtx.is_empty();
isl::set MACtx;
// Check if we know that this pointer can be speculatively accessed.
if (canAlwaysBeHoisted(MA, StmtInvalidCtxIsEmpty, MAInvalidCtxIsEmpty,
NonHoistableCtxIsEmpty)) {
MACtx = isl::set::universe(DomainCtx.get_space());
} else {
MACtx = DomainCtx;
MACtx = MACtx.subtract(MAInvalidCtx.unite(NHCtx));
MACtx = MACtx.gist_params(getContext());
}
bool Consolidated = false;
for (auto &IAClass : InvariantEquivClasses) {
if (PointerSCEV != IAClass.IdentifyingPointer || Ty != IAClass.AccessType)
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 = IAClass.InvariantAccesses;
if (!MAs.empty()) {
auto *LastMA = MAs.front();
isl::set AR = MA->getAccessRelation().range();
isl::set LastAR = LastMA->getAccessRelation().range();
bool SameAR = AR.is_equal(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 = IAClass.ExecutionContext;
if (IAClassDomainCtx)
IAClassDomainCtx = IAClassDomainCtx.unite(MACtx).coalesce();
else
IAClassDomainCtx = MACtx;
IAClass.ExecutionContext = IAClassDomainCtx;
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(
InvariantEquivClassTy{PointerSCEV, MemoryAccessList{MA}, MACtx, Ty});
}
}
/// Check if an access range is too complex.
///
/// An access range is too complex, if it contains either many disjuncts or
/// very complex expressions. As a simple heuristic, we assume if a set to
/// be too complex if the sum of existentially quantified dimensions and
/// set dimensions is larger than a threshold. This reliably detects both
/// sets with many disjuncts as well as sets with many divisions as they
/// arise in h264.
///
/// @param AccessRange The range to check for complexity.
///
/// @returns True if the access range is too complex.
static bool isAccessRangeTooComplex(isl::set AccessRange) {
unsigned NumTotalDims = 0;
auto CountDimensions = [&NumTotalDims](isl::basic_set BSet) -> isl::stat {
NumTotalDims += BSet.dim(isl::dim::div);
NumTotalDims += BSet.dim(isl::dim::set);
return isl::stat::ok;
};
AccessRange.foreach_basic_set(CountDimensions);
if (NumTotalDims > MaxDimensionsInAccessRange)
return true;
return false;
}
isl::set Scop::getNonHoistableCtx(MemoryAccess *Access, 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() ||
Access->isMemoryIntrinsic())
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;
isl::map AccessRelation = give(Access->getAccessRelation().release());
assert(!AccessRelation.is_empty());
if (AccessRelation.involves_dims(isl::dim::in, 0, Stmt.getNumIterators()))
return nullptr;
AccessRelation = AccessRelation.intersect_domain(Stmt.getDomain());
isl::set SafeToLoad;
auto &DL = getFunction().getParent()->getDataLayout();
if (isSafeToLoadUnconditionally(LI->getPointerOperand(), LI->getAlignment(),
DL)) {
SafeToLoad = isl::set::universe(AccessRelation.get_space().range());
} else if (BB != LI->getParent()) {
// Skip accesses in non-affine subregions as they might not be executed
// under the same condition as the entry of the non-affine subregion.
return nullptr;
} else {
SafeToLoad = AccessRelation.range();
}
if (isAccessRangeTooComplex(AccessRelation.range()))
return nullptr;
isl::union_map Written = Writes.intersect_range(SafeToLoad);
isl::set WrittenCtx = Written.params();
bool IsWritten = !WrittenCtx.is_empty();
if (!IsWritten)
return WrittenCtx;
WrittenCtx = WrittenCtx.remove_divs();
bool TooComplex =
isl_set_n_basic_set(WrittenCtx.get()) >= MaxDisjunctsInDomain;
if (TooComplex || !isRequiredInvariantLoad(LI))
return nullptr;
addAssumption(INVARIANTLOAD, WrittenCtx, LI->getDebugLoc(), AS_RESTRICTION,
LI->getParent());
return WrittenCtx;
}
void Scop::verifyInvariantLoads() {
auto &RIL = getRequiredInvariantLoads();
for (LoadInst *LI : RIL) {
assert(LI && contains(LI));
// If there exists a statement in the scop which has a memory access for
// @p LI, then mark this scop as infeasible for optimization.
for (ScopStmt &Stmt : Stmts)
if (Stmt.getArrayAccessOrNULLFor(LI)) {
invalidate(INVARIANTLOAD, LI->getDebugLoc(), LI->getParent());
return;
}
}
}
void Scop::hoistInvariantLoads() {
if (!PollyInvariantLoadHoisting)
return;
isl::union_map Writes = getWrites();
for (ScopStmt &Stmt : *this) {
InvariantAccessesTy InvariantAccesses;
for (MemoryAccess *Access : Stmt)
if (isl::set 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);
}
}
/// Find the canonical scop array info object for a set of invariant load
/// hoisted loads. The canonical array is the one that corresponds to the
/// first load in the list of accesses which is used as base pointer of a
/// scop array.
static const ScopArrayInfo *findCanonicalArray(Scop *S,
MemoryAccessList &Accesses) {
for (MemoryAccess *Access : Accesses) {
const ScopArrayInfo *CanonicalArray = S->getScopArrayInfoOrNull(
Access->getAccessInstruction(), MemoryKind::Array);
if (CanonicalArray)
return CanonicalArray;
}
return nullptr;
}
/// Check if @p Array severs as base array in an invariant load.
static bool isUsedForIndirectHoistedLoad(Scop *S, const ScopArrayInfo *Array) {
for (InvariantEquivClassTy &EqClass2 : S->getInvariantAccesses())
for (MemoryAccess *Access2 : EqClass2.InvariantAccesses)
if (Access2->getScopArrayInfo() == Array)
return true;
return false;
}
/// Replace the base pointer arrays in all memory accesses referencing @p Old,
/// with a reference to @p New.
static void replaceBasePtrArrays(Scop *S, const ScopArrayInfo *Old,
const ScopArrayInfo *New) {
for (ScopStmt &Stmt : *S)
for (MemoryAccess *Access : Stmt) {
if (Access->getLatestScopArrayInfo() != Old)
continue;
isl::id Id = New->getBasePtrId();
isl::map Map = Access->getAccessRelation();
Map = Map.set_tuple_id(isl::dim::out, Id);
Access->setAccessRelation(Map);
}
}
void Scop::canonicalizeDynamicBasePtrs() {
for (InvariantEquivClassTy &EqClass : InvariantEquivClasses) {
MemoryAccessList &BasePtrAccesses = EqClass.InvariantAccesses;
const ScopArrayInfo *CanonicalBasePtrSAI =
findCanonicalArray(this, BasePtrAccesses);
if (!CanonicalBasePtrSAI)
continue;
for (MemoryAccess *BasePtrAccess : BasePtrAccesses) {
const ScopArrayInfo *BasePtrSAI = getScopArrayInfoOrNull(
BasePtrAccess->getAccessInstruction(), MemoryKind::Array);
if (!BasePtrSAI || BasePtrSAI == CanonicalBasePtrSAI ||
!BasePtrSAI->isCompatibleWith(CanonicalBasePtrSAI))
continue;
// we currently do not canonicalize arrays where some accesses are
// hoisted as invariant loads. If we would, we need to update the access
// function of the invariant loads as well. However, as this is not a
// very common situation, we leave this for now to avoid further
// complexity increases.
if (isUsedForIndirectHoistedLoad(this, BasePtrSAI))
continue;
replaceBasePtrArrays(this, BasePtrSAI, CanonicalBasePtrSAI);
}
}
}
ScopArrayInfo *Scop::getOrCreateScopArrayInfo(Value *BasePtr, Type *ElementType,
ArrayRef<const SCEV *> Sizes,
MemoryKind Kind,
const char *BaseName) {
assert((BasePtr || BaseName) &&
"BasePtr and BaseName can not be nullptr at the same time.");
assert(!(BasePtr && BaseName) && "BaseName is redundant.");
auto &SAI = BasePtr ? ScopArrayInfoMap[std::make_pair(BasePtr, Kind)]
: ScopArrayNameMap[BaseName];
if (!SAI) {
auto &DL = getFunction().getParent()->getDataLayout();
SAI.reset(new ScopArrayInfo(BasePtr, ElementType, getIslCtx(), Sizes, Kind,
DL, this, BaseName));
ScopArrayInfoSet.insert(SAI.get());
} 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();
}
ScopArrayInfo *Scop::createScopArrayInfo(Type *ElementType,
const std::string &BaseName,
const std::vector<unsigned> &Sizes) {
auto *DimSizeType = Type::getInt64Ty(getSE()->getContext());
std::vector<const SCEV *> SCEVSizes;
for (auto size : Sizes)
if (size)
SCEVSizes.push_back(getSE()->getConstant(DimSizeType, size, false));
else
SCEVSizes.push_back(nullptr);
auto *SAI = getOrCreateScopArrayInfo(nullptr, ElementType, SCEVSizes,
MemoryKind::Array, BaseName.c_str());
return SAI;
}
const ScopArrayInfo *Scop::getScopArrayInfoOrNull(Value *BasePtr,
MemoryKind Kind) {
auto *SAI = ScopArrayInfoMap[std::make_pair(BasePtr, Kind)].get();
return SAI;
}
const ScopArrayInfo *Scop::getScopArrayInfo(Value *BasePtr, MemoryKind Kind) {
auto *SAI = getScopArrayInfoOrNull(BasePtr, Kind);
assert(SAI && "No ScopArrayInfo available for this base pointer");
return SAI;
}
std::string Scop::getContextStr() const { return getContext().to_str(); }
std::string Scop::getAssumedContextStr() const {
assert(AssumedContext && "Assumed context not yet built");
return AssumedContext.to_str();
}
std::string Scop::getInvalidContextStr() const {
return InvalidContext.to_str();
}
std::string Scop::getNameStr() const {
std::string ExitName, EntryName;
std::tie(EntryName, ExitName) = getEntryExitStr();
return EntryName + "---" + ExitName;
}
std::pair<std::string, std::string> Scop::getEntryExitStr() 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 std::make_pair(EntryName, ExitName);
}
isl::set Scop::getContext() const { return Context; }
isl::space Scop::getParamSpace() const { return getContext().get_space(); }
isl::space Scop::getFullParamSpace() const {
std::vector<isl::id> FortranIDs;
FortranIDs = getFortranArrayIds(arrays());
isl::space Space = isl::space::params_alloc(
getIslCtx(), ParameterIds.size() + FortranIDs.size());
unsigned PDim = 0;
for (const SCEV *Parameter : Parameters) {
isl::id Id = getIdForParam(Parameter);
Space = Space.set_dim_id(isl::dim::param, PDim++, Id);
}
for (isl::id Id : FortranIDs)
Space = Space.set_dim_id(isl::dim::param, PDim++, Id);
return Space;
}
isl::set Scop::getAssumedContext() const {
assert(AssumedContext && "Assumed context not yet built");
return AssumedContext;
}
bool Scop::isProfitable(bool ScalarsAreUnprofitable) const {
if (PollyProcessUnprofitable)
return true;
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->isLatestArrayKind();
ContainsScalarAccs |= MA->isLatestScalarKind();
}
if (!ScalarsAreUnprofitable || (ContainsArrayAccs && !ContainsScalarAccs))
OptimizableStmtsOrLoops += Stmt.getNumIterators();
}
return OptimizableStmtsOrLoops > 1;
}
bool Scop::hasFeasibleRuntimeContext() const {
auto PositiveContext = getAssumedContext();
auto NegativeContext = getInvalidContext();
PositiveContext = addNonEmptyDomainConstraints(PositiveContext);
// addNonEmptyDomainConstraints returns null if ScopStmts have a null domain
if (!PositiveContext)
return false;
bool IsFeasible = !(PositiveContext.is_empty() ||
PositiveContext.is_subset(NegativeContext));
if (!IsFeasible)
return false;
auto DomainContext = getDomains().params();
IsFeasible = !DomainContext.is_subset(NegativeContext);
IsFeasible &= !Context.is_subset(NegativeContext);
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::set Set, AssumptionSign Sign) {
if (Sign == AS_ASSUMPTION) {
if (Context.is_subset(Set))
return false;
if (AssumedContext.is_subset(Set))
return false;
} else {
if (Set.is_disjoint(Context))
return false;
if (Set.is_subset(InvalidContext))
return false;
}
return true;
}
bool Scop::trackAssumption(AssumptionKind Kind, isl::set Set, DebugLoc Loc,
AssumptionSign Sign, BasicBlock *BB) {
if (PollyRemarksMinimal && !isEffectiveAssumption(Set, Sign))
return false;
// Do never emit trivial assumptions as they only clutter the output.
if (!PollyRemarksMinimal) {
isl::set Univ;
if (Sign == AS_ASSUMPTION)
Univ = isl::set::universe(Set.get_space());
bool IsTrivial = (Sign == AS_RESTRICTION && Set.is_empty()) ||
(Sign == AS_ASSUMPTION && Univ.is_equal(Set));
if (IsTrivial)
return false;
}
switch (Kind) {
case ALIASING:
AssumptionsAliasing++;
break;
case INBOUNDS:
AssumptionsInbounds++;
break;
case WRAPPING:
AssumptionsWrapping++;
break;
case UNSIGNED:
AssumptionsUnsigned++;
break;
case COMPLEXITY:
AssumptionsComplexity++;
break;
case PROFITABLE:
AssumptionsUnprofitable++;
break;
case ERRORBLOCK:
AssumptionsErrorBlock++;
break;
case INFINITELOOP:
AssumptionsInfiniteLoop++;
break;
case INVARIANTLOAD:
AssumptionsInvariantLoad++;
break;
case DELINEARIZATION:
AssumptionsDelinearization++;
break;
}
auto Suffix = Sign == AS_ASSUMPTION ? " assumption:\t" : " restriction:\t";
std::string Msg = toString(Kind) + Suffix + Set.to_str();
if (BB)
ORE.emit(OptimizationRemarkAnalysis(DEBUG_TYPE, "AssumpRestrict", Loc, BB)
<< Msg);
else
ORE.emit(OptimizationRemarkAnalysis(DEBUG_TYPE, "AssumpRestrict", Loc,
R.getEntry())
<< Msg);
return true;
}
void Scop::addAssumption(AssumptionKind Kind, isl::set Set, DebugLoc Loc,
AssumptionSign Sign, BasicBlock *BB) {
// Simplify the assumptions/restrictions first.
Set = Set.gist_params(getContext());
if (!trackAssumption(Kind, Set, Loc, Sign, BB))
return;
if (Sign == AS_ASSUMPTION)
AssumedContext = AssumedContext.intersect(Set).coalesce();
else
InvalidContext = InvalidContext.unite(Set).coalesce();
}
void Scop::recordAssumption(AssumptionKind Kind, isl::set Set, DebugLoc Loc,
AssumptionSign Sign, BasicBlock *BB) {
assert((Set.is_params() || BB) &&
"Assumptions without a basic block must be parameter sets");
RecordedAssumptions.push_back({Kind, Sign, Set, Loc, BB});
}
void Scop::addRecordedAssumptions() {
while (!RecordedAssumptions.empty()) {
Assumption AS = RecordedAssumptions.pop_back_val();
if (!AS.BB) {
addAssumption(AS.Kind, AS.Set, AS.Loc, AS.Sign, nullptr /* BasicBlock */);
continue;
}
// If the domain was deleted the assumptions are void.
isl_set *Dom = getDomainConditions(AS.BB).release();
if (!Dom)
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 restriction not an
// assumption.
isl_set *S = AS.Set.copy();
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, isl::manage(S), AS.Loc, AS_RESTRICTION, AS.BB);
}
}
void Scop::invalidate(AssumptionKind Kind, DebugLoc Loc, BasicBlock *BB) {
DEBUG(dbgs() << "Invalidate SCoP because of reason " << Kind << "\n");
addAssumption(Kind, isl::set::empty(getParamSpace()), Loc, AS_ASSUMPTION, BB);
}
isl::set Scop::getInvalidContext() const { return 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, bool PrintInstructions) const {
OS << "Statements {\n";
for (const ScopStmt &Stmt : *this) {
OS.indent(4);
Stmt.print(OS, PrintInstructions);
}
OS.indent(4) << "}\n";
}
void Scop::printArrayInfo(raw_ostream &OS) const {
OS << "Arrays {\n";
for (auto &Array : arrays())
Array->print(OS);
OS.indent(4) << "}\n";
OS.indent(4) << "Arrays (Bounds as pw_affs) {\n";
for (auto &Array : arrays())
Array->print(OS, /* SizeAsPwAff */ true);
OS.indent(4) << "}\n";
}
void Scop::print(raw_ostream &OS, bool PrintInstructions) 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 = IAClass.InvariantAccesses;
if (MAs.empty()) {
OS.indent(12) << "Class Pointer: " << *IAClass.IdentifyingPointer << "\n";
} else {
MAs.front()->print(OS);
OS.indent(12) << "Execution Context: " << IAClass.ExecutionContext
<< "\n";
}
}
OS.indent(4) << "}\n";
printContext(OS.indent(4));
printArrayInfo(OS.indent(4));
printAliasAssumptions(OS);
printStatements(OS.indent(4), PrintInstructions);
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void Scop::dump() const { print(dbgs(), true); }
#endif
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 code 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, BB);
return Affinator.getPwAff(SE->getZero(E->getType()), BB);
}
isl::union_set Scop::getDomains() const {
isl_space *EmptySpace = isl_space_params_alloc(getIslCtx().get(), 0);
isl_union_set *Domain = isl_union_set_empty(EmptySpace);
for (const ScopStmt &Stmt : *this)
Domain = isl_union_set_add_set(Domain, Stmt.getDomain().release());
return isl::manage(Domain);
}
isl::pw_aff Scop::getPwAffOnly(const SCEV *E, BasicBlock *BB) {
PWACtx PWAC = getPwAff(E, BB);
return PWAC.first;
}
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 = AccessDomain.intersect_domain(Domain);
Accesses = Accesses.add_map(AccessDomain);
}
}
return Accesses.coalesce();
}
isl::union_map Scop::getMustWrites() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isMustWrite(); });
}
isl::union_map Scop::getMayWrites() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isMayWrite(); });
}
isl::union_map Scop::getWrites() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isWrite(); });
}
isl::union_map Scop::getReads() {
return getAccessesOfType([](MemoryAccess &MA) { return MA.isRead(); });
}
isl::union_map Scop::getAccesses() {
return getAccessesOfType([](MemoryAccess &MA) { return true; });
}
isl::union_map Scop::getAccesses(ScopArrayInfo *Array) {
return getAccessesOfType(
[Array](MemoryAccess &MA) { return MA.getScopArrayInfo() == Array; });
}
// Check whether @p Node is an extension node.
//
// @return true if @p Node is an extension node.
isl_bool isNotExtNode(__isl_keep isl_schedule_node *Node, void *User) {
if (isl_schedule_node_get_type(Node) == isl_schedule_node_extension)
return isl_bool_error;
else
return isl_bool_true;
}
bool Scop::containsExtensionNode(isl::schedule Schedule) {
return isl_schedule_foreach_schedule_node_top_down(
Schedule.keep(), isNotExtNode, nullptr) == isl_stat_error;
}
isl::union_map Scop::getSchedule() const {
auto Tree = getScheduleTree();
if (containsExtensionNode(Tree))
return nullptr;
return Tree.get_map();
}
isl::schedule Scop::getScheduleTree() const {
return Schedule.intersect_domain(getDomains());
}
void Scop::setSchedule(isl::union_map NewSchedule) {
auto S = isl::schedule::from_domain(getDomains());
Schedule = S.insert_partial_schedule(
isl::multi_union_pw_aff::from_union_map(NewSchedule));
}
void Scop::setScheduleTree(isl::schedule NewSchedule) {
Schedule = NewSchedule;
}
bool Scop::restrictDomains(isl::union_set Domain) {
bool Changed = false;
for (ScopStmt &Stmt : *this) {
isl::union_set StmtDomain = isl::union_set(Stmt.getDomain());
isl::union_set NewStmtDomain = StmtDomain.intersect(Domain);
if (StmtDomain.is_subset(NewStmtDomain))
continue;
Changed = true;
NewStmtDomain = NewStmtDomain.coalesce();
if (NewStmtDomain.is_empty())
Stmt.restrictDomain(isl::set::empty(Stmt.getDomainSpace()));
else
Stmt.restrictDomain(isl::set(NewStmtDomain));
}
return Changed;
}
ScalarEvolution *Scop::getSE() const { return SE; }
// 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::multi_union_pw_aff mapToDimension(isl::union_set USet, int N) {
assert(N >= 0);
assert(USet);
assert(!USet.is_empty());
auto Result = isl::union_pw_multi_aff::empty(USet.get_space());
auto Lambda = [&Result, N](isl::set S) -> isl::stat {
int Dim = S.dim(isl::dim::set);
auto PMA = isl::pw_multi_aff::project_out_map(S.get_space(), isl::dim::set,
N, Dim - N);
if (N > 1)
PMA = PMA.drop_dims(isl::dim::out, 0, N - 1);
Result = Result.add_pw_multi_aff(PMA);
return isl::stat::ok;
};
isl::stat Res = USet.foreach_set(Lambda);
(void)Res;
assert(Res == isl::stat::ok);
return isl::multi_union_pw_aff(isl::union_pw_multi_aff(Result));
}
void Scop::addScopStmt(BasicBlock *BB, StringRef Name, Loop *SurroundingLoop,
std::vector<Instruction *> Instructions) {
assert(BB && "Unexpected nullptr!");
Stmts.emplace_back(*this, *BB, Name, SurroundingLoop, Instructions);
auto *Stmt = &Stmts.back();
StmtMap[BB].push_back(Stmt);
for (Instruction *Inst : Instructions) {
assert(!InstStmtMap.count(Inst) &&
"Unexpected statement corresponding to the instruction.");
InstStmtMap[Inst] = Stmt;
}
}
void Scop::addScopStmt(Region *R, StringRef Name, Loop *SurroundingLoop,
std::vector<Instruction *> Instructions) {
assert(R && "Unexpected nullptr!");
Stmts.emplace_back(*this, *R, Name, SurroundingLoop, Instructions);
auto *Stmt = &Stmts.back();
for (Instruction *Inst : Instructions) {
assert(!InstStmtMap.count(Inst) &&
"Unexpected statement corresponding to the instruction.");
InstStmtMap[Inst] = Stmt;
}
for (BasicBlock *BB : R->blocks()) {
StmtMap[BB].push_back(Stmt);
if (BB == R->getEntry())
continue;
for (Instruction &Inst : *BB) {
assert(!InstStmtMap.count(&Inst) &&
"Unexpected statement corresponding to the instruction.");
InstStmtMap[&Inst] = Stmt;
}
}
}
ScopStmt *Scop::addScopStmt(isl::map SourceRel, isl::map TargetRel,
isl::set Domain) {
#ifndef NDEBUG
isl::set SourceDomain = SourceRel.domain();
isl::set TargetDomain = TargetRel.domain();
assert(Domain.is_subset(TargetDomain) &&
"Target access not defined for complete statement domain");
assert(Domain.is_subset(SourceDomain) &&
"Source access not defined for complete statement domain");
#endif
Stmts.emplace_back(*this, SourceRel, TargetRel, Domain);
CopyStmtsNum++;
return &(Stmts.back());
}
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.empty()) {
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);
}
}
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;
}
}
assert(LoopStack.rbegin() != LoopStack.rend());
auto LoopData = LoopStack.rbegin();
LoopData->NumBlocksProcessed += getNumBlocksInRegionNode(RN);
for (auto *Stmt : getStmtListFor(RN)) {
isl::union_set UDomain{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.
size_t Dimension = LoopStack.size();
while (LoopData->L &&
LoopData->NumBlocksProcessed == getNumBlocksInLoop(LoopData->L)) {
isl::schedule Schedule = LoopData->Schedule;
auto NumBlocksProcessed = LoopData->NumBlocksProcessed;
assert(std::next(LoopData) != LoopStack.rend());
++LoopData;
--Dimension;
if (Schedule) {
isl::union_set Domain = Schedule.get_domain();
isl::multi_union_pw_aff MUPA = mapToDimension(Domain, Dimension);
Schedule = Schedule.insert_partial_schedule(MUPA);
LoopData->Schedule = combineInSequence(LoopData->Schedule, Schedule);
}
LoopData->NumBlocksProcessed += NumBlocksProcessed;
}
// Now pop all loops processed up there from the LoopStack
LoopStack.erase(LoopStack.begin() + Dimension, LoopStack.end());
}
ArrayRef<ScopStmt *> Scop::getStmtListFor(BasicBlock *BB) const {
auto StmtMapIt = StmtMap.find(BB);
if (StmtMapIt == StmtMap.end())
return {};
return StmtMapIt->second;
}
ScopStmt *Scop::getIncomingStmtFor(const Use &U) const {
auto *PHI = cast<PHINode>(U.getUser());
BasicBlock *IncomingBB = PHI->getIncomingBlock(U);
// If the value is a non-synthesizable from the incoming block, use the
// statement that contains it as user statement.
if (auto *IncomingInst = dyn_cast<Instruction>(U.get())) {
if (IncomingInst->getParent() == IncomingBB) {
if (ScopStmt *IncomingStmt = getStmtFor(IncomingInst))
return IncomingStmt;
}
}
// Otherwise, use the epilogue/last statement.
return getLastStmtFor(IncomingBB);
}
ScopStmt *Scop::getLastStmtFor(BasicBlock *BB) const {
ArrayRef<ScopStmt *> StmtList = getStmtListFor(BB);
if (!StmtList.empty())
return StmtList.back();
return nullptr;
}
ArrayRef<ScopStmt *> Scop::getStmtListFor(RegionNode *RN) const {
if (RN->isSubRegion())
return getStmtListFor(RN->getNodeAs<Region>());
return getStmtListFor(RN->getNodeAs<BasicBlock>());
}
ArrayRef<ScopStmt *> Scop::getStmtListFor(Region *R) const {
return getStmtListFor(R->getEntry());
}
int Scop::getRelativeLoopDepth(const Loop *L) const {
if (!L || !R.contains(L))
return -1;
// outermostLoopInRegion always returns nullptr for top level regions
if (R.isTopLevelRegion()) {
// LoopInfo's depths start at 1, we start at 0
return L->getLoopDepth() - 1;
} else {
Loop *OuterLoop = R.outermostLoopInRegion(const_cast<Loop *>(L));
assert(OuterLoop);
return L->getLoopDepth() - OuterLoop->getLoopDepth();
}
}
ScopArrayInfo *Scop::getArrayInfoByName(const std::string BaseName) {
for (auto &SAI : arrays()) {
if (SAI->getName() == BaseName)
return SAI;
}
return nullptr;
}
void Scop::addAccessData(MemoryAccess *Access) {
const ScopArrayInfo *SAI = Access->getOriginalScopArrayInfo();
assert(SAI && "can only use after access relations have been constructed");
if (Access->isOriginalValueKind() && Access->isRead())
ValueUseAccs[SAI].push_back(Access);
else if (Access->isOriginalAnyPHIKind() && Access->isWrite())
PHIIncomingAccs[SAI].push_back(Access);
}
void Scop::removeAccessData(MemoryAccess *Access) {
if (Access->isOriginalValueKind() && Access->isWrite()) {
ValueDefAccs.erase(Access->getAccessValue());
} else if (Access->isOriginalValueKind() && Access->isRead()) {
auto &Uses = ValueUseAccs[Access->getScopArrayInfo()];
std::remove(Uses.begin(), Uses.end(), Access);
} else if (Access->isOriginalPHIKind() && Access->isRead()) {
PHINode *PHI = cast<PHINode>(Access->getAccessInstruction());
PHIReadAccs.erase(PHI);
} else if (Access->isOriginalAnyPHIKind() && Access->isWrite()) {
auto &Incomings = PHIIncomingAccs[Access->getScopArrayInfo()];
std::remove(Incomings.begin(), Incomings.end(), Access);
}
}
MemoryAccess *Scop::getValueDef(const ScopArrayInfo *SAI) const {
assert(SAI->isValueKind());
Instruction *Val = dyn_cast<Instruction>(SAI->getBasePtr());
if (!Val)
return nullptr;
return ValueDefAccs.lookup(Val);
}
ArrayRef<MemoryAccess *> Scop::getValueUses(const ScopArrayInfo *SAI) const {
assert(SAI->isValueKind());
auto It = ValueUseAccs.find(SAI);
if (It == ValueUseAccs.end())
return {};
return It->second;
}
MemoryAccess *Scop::getPHIRead(const ScopArrayInfo *SAI) const {
assert(SAI->isPHIKind() || SAI->isExitPHIKind());
if (SAI->isExitPHIKind())
return nullptr;
PHINode *PHI = cast<PHINode>(SAI->getBasePtr());
return PHIReadAccs.lookup(PHI);
}
ArrayRef<MemoryAccess *> Scop::getPHIIncomings(const ScopArrayInfo *SAI) const {
assert(SAI->isPHIKind() || SAI->isExitPHIKind());
auto It = PHIIncomingAccs.find(SAI);
if (It == PHIIncomingAccs.end())
return {};
return It->second;
}
bool Scop::isEscaping(Instruction *Inst) {
assert(contains(Inst) && "The concept of escaping makes only sense for "
"values defined inside the SCoP");
for (Use &Use : Inst->uses()) {
BasicBlock *UserBB = getUseBlock(Use);
if (!contains(UserBB))
return true;
// When the SCoP region exit needs to be simplified, PHIs in the region exit
// move to a new basic block such that its incoming blocks are not in the
// SCoP anymore.
if (hasSingleExitEdge() && isa<PHINode>(Use.getUser()) &&
isExit(cast<PHINode>(Use.getUser())->getParent()))
return true;
}
return false;
}
Scop::ScopStatistics Scop::getStatistics() const {
ScopStatistics Result;
#if !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
auto LoopStat = ScopDetection::countBeneficialLoops(&R, *SE, *getLI(), 0);
int NumTotalLoops = LoopStat.NumLoops;
Result.NumBoxedLoops = getBoxedLoops().size();
Result.NumAffineLoops = NumTotalLoops - Result.NumBoxedLoops;
for (const ScopStmt &Stmt : *this) {
isl::set Domain = Stmt.getDomain().intersect_params(getContext());
bool IsInLoop = Stmt.getNumIterators() >= 1;
for (MemoryAccess *MA : Stmt) {
if (!MA->isWrite())
continue;
if (MA->isLatestValueKind()) {
Result.NumValueWrites += 1;
if (IsInLoop)
Result.NumValueWritesInLoops += 1;
}
if (MA->isLatestAnyPHIKind()) {
Result.NumPHIWrites += 1;
if (IsInLoop)
Result.NumPHIWritesInLoops += 1;
}
isl::set AccSet =
MA->getAccessRelation().intersect_domain(Domain).range();
if (AccSet.is_singleton()) {
Result.NumSingletonWrites += 1;
if (IsInLoop)
Result.NumSingletonWritesInLoops += 1;
}
}
}
#endif
return Result;
}
raw_ostream &polly::operator<<(raw_ostream &OS, const Scop &scop) {
scop.print(OS, PollyPrintInstructions);
return OS;
}
//===----------------------------------------------------------------------===//
void ScopInfoRegionPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LoopInfoWrapperPass>();
AU.addRequired<RegionInfoPass>();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequiredTransitive<ScalarEvolutionWrapperPass>();
AU.addRequiredTransitive<ScopDetectionWrapperPass>();
AU.addRequired<AAResultsWrapperPass>();
AU.addRequired<AssumptionCacheTracker>();
AU.addRequired<OptimizationRemarkEmitterWrapperPass>();
AU.setPreservesAll();
}
void updateLoopCountStatistic(ScopDetection::LoopStats Stats,
Scop::ScopStatistics ScopStats) {
assert(Stats.NumLoops == ScopStats.NumAffineLoops + ScopStats.NumBoxedLoops);
NumScops++;
NumLoopsInScop += Stats.NumLoops;
MaxNumLoopsInScop =
std::max(MaxNumLoopsInScop.getValue(), (unsigned)Stats.NumLoops);
if (Stats.MaxDepth == 1)
NumScopsDepthOne++;
else if (Stats.MaxDepth == 2)
NumScopsDepthTwo++;
else if (Stats.MaxDepth == 3)
NumScopsDepthThree++;
else if (Stats.MaxDepth == 4)
NumScopsDepthFour++;
else if (Stats.MaxDepth == 5)
NumScopsDepthFive++;
else
NumScopsDepthLarger++;
NumAffineLoops += ScopStats.NumAffineLoops;
NumBoxedLoops += ScopStats.NumBoxedLoops;
NumValueWrites += ScopStats.NumValueWrites;
NumValueWritesInLoops += ScopStats.NumValueWritesInLoops;
NumPHIWrites += ScopStats.NumPHIWrites;
NumPHIWritesInLoops += ScopStats.NumPHIWritesInLoops;
NumSingletonWrites += ScopStats.NumSingletonWrites;
NumSingletonWritesInLoops += ScopStats.NumSingletonWritesInLoops;
}
bool ScopInfoRegionPass::runOnRegion(Region *R, RGPassManager &RGM) {
auto &SD = getAnalysis<ScopDetectionWrapperPass>().getSD();
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);
auto &ORE = getAnalysis<OptimizationRemarkEmitterWrapperPass>().getORE();
ScopBuilder SB(R, AC, AA, DL, DT, LI, SD, SE, ORE);
S = SB.getScop(); // take ownership of scop object
#if !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
if (S) {
ScopDetection::LoopStats Stats =
ScopDetection::countBeneficialLoops(&S->getRegion(), SE, LI, 0);
updateLoopCountStatistic(Stats, S->getStatistics());
}
#endif
return false;
}
void ScopInfoRegionPass::print(raw_ostream &OS, const Module *) const {
if (S)
S->print(OS, PollyPrintInstructions);
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(ScopDetectionWrapperPass);
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass);
INITIALIZE_PASS_END(ScopInfoRegionPass, "polly-scops",
"Polly - Create polyhedral description of Scops", false,
false)
//===----------------------------------------------------------------------===//
ScopInfo::ScopInfo(const DataLayout &DL, ScopDetection &SD, ScalarEvolution &SE,
LoopInfo &LI, AliasAnalysis &AA, DominatorTree &DT,
AssumptionCache &AC, OptimizationRemarkEmitter &ORE)
: DL(DL), SD(SD), SE(SE), LI(LI), AA(AA), DT(DT), AC(AC), ORE(ORE) {
recompute();
}
void ScopInfo::recompute() {
RegionToScopMap.clear();
/// Create polyhedral description 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, ORE);
std::unique_ptr<Scop> S = SB.getScop();
if (!S)
continue;
#if !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
ScopDetection::LoopStats Stats =
ScopDetection::countBeneficialLoops(&S->getRegion(), SE, LI, 0);
updateLoopCountStatistic(Stats, S->getStatistics());
#endif
bool Inserted = RegionToScopMap.insert({R, std::move(S)}).second;
assert(Inserted && "Building Scop for the same region twice!");
(void)Inserted;
}
}
bool ScopInfo::invalidate(Function &F, const PreservedAnalyses &PA,
FunctionAnalysisManager::Invalidator &Inv) {
// Check whether the analysis, all analyses on functions have been preserved
// or anything we're holding references to is being invalidated
auto PAC = PA.getChecker<ScopInfoAnalysis>();
return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>()) ||
Inv.invalidate<ScopAnalysis>(F, PA) ||
Inv.invalidate<ScalarEvolutionAnalysis>(F, PA) ||
Inv.invalidate<LoopAnalysis>(F, PA) ||
Inv.invalidate<AAManager>(F, PA) ||
Inv.invalidate<DominatorTreeAnalysis>(F, PA) ||
Inv.invalidate<AssumptionAnalysis>(F, PA);
}
AnalysisKey ScopInfoAnalysis::Key;
ScopInfoAnalysis::Result ScopInfoAnalysis::run(Function &F,
FunctionAnalysisManager &FAM) {
auto &SD = FAM.getResult<ScopAnalysis>(F);
auto &SE = FAM.getResult<ScalarEvolutionAnalysis>(F);
auto &LI = FAM.getResult<LoopAnalysis>(F);
auto &AA = FAM.getResult<AAManager>(F);
auto &DT = FAM.getResult<DominatorTreeAnalysis>(F);
auto &AC = FAM.getResult<AssumptionAnalysis>(F);
auto &DL = F.getParent()->getDataLayout();
auto &ORE = FAM.getResult<OptimizationRemarkEmitterAnalysis>(F);
return {DL, SD, SE, LI, AA, DT, AC, ORE};
}
PreservedAnalyses ScopInfoPrinterPass::run(Function &F,
FunctionAnalysisManager &FAM) {
auto &SI = FAM.getResult<ScopInfoAnalysis>(F);
// Since the legacy PM processes Scops in bottom up, we print them in reverse
// order here to keep the output persistent
for (auto &It : reverse(SI)) {
if (It.second)
It.second->print(Stream, PollyPrintInstructions);
else
Stream << "Invalid Scop!\n";
}
return PreservedAnalyses::all();
}
void ScopInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LoopInfoWrapperPass>();
AU.addRequired<RegionInfoPass>();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequiredTransitive<ScalarEvolutionWrapperPass>();
AU.addRequiredTransitive<ScopDetectionWrapperPass>();
AU.addRequired<AAResultsWrapperPass>();
AU.addRequired<AssumptionCacheTracker>();
AU.addRequired<OptimizationRemarkEmitterWrapperPass>();
AU.setPreservesAll();
}
bool ScopInfoWrapperPass::runOnFunction(Function &F) {
auto &SD = getAnalysis<ScopDetectionWrapperPass>().getSD();
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);
auto &ORE = getAnalysis<OptimizationRemarkEmitterWrapperPass>().getORE();
Result.reset(new ScopInfo{DL, SD, SE, LI, AA, DT, AC, ORE});
return false;
}
void ScopInfoWrapperPass::print(raw_ostream &OS, const Module *) const {
for (auto &It : *Result) {
if (It.second)
It.second->print(OS, PollyPrintInstructions);
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(ScopDetectionWrapperPass);
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass);
INITIALIZE_PASS_END(
ScopInfoWrapperPass, "polly-function-scops",
"Polly - Create polyhedral description of all Scops of a function", false,
false)