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//===- polly/ScopInfo.h -----------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Store the polyhedral model representation of a static control flow region,
// also called SCoP (Static Control Part).
//
// This representation is shared among several tools in the polyhedral
// community, which are e.g. CLooG, Pluto, Loopo, Graphite.
//
//===----------------------------------------------------------------------===//
#ifndef POLLY_SCOPINFO_H
#define POLLY_SCOPINFO_H
#include "polly/ScopDetection.h"
#include "polly/Support/SCEVAffinator.h"
#include "polly/Support/ScopHelper.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/Analysis/RegionPass.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Pass.h"
#include "isl/isl-noexceptions.h"
#include <cassert>
#include <cstddef>
#include <forward_list>
namespace llvm {
void initializeScopInfoRegionPassPass(PassRegistry &);
void initializeScopInfoWrapperPassPass(PassRegistry &);
} // end namespace llvm
namespace polly {
using llvm::AnalysisInfoMixin;
using llvm::ArrayRef;
using llvm::AssertingVH;
using llvm::AssumptionCache;
using llvm::cast;
using llvm::DataLayout;
using llvm::DenseMap;
using llvm::DenseSet;
using llvm::function_ref;
using llvm::isa;
using llvm::iterator_range;
using llvm::LoadInst;
using llvm::make_range;
using llvm::MapVector;
using llvm::MemIntrinsic;
using llvm::Optional;
using llvm::PassInfoMixin;
using llvm::PHINode;
using llvm::RegionNode;
using llvm::RegionPass;
using llvm::RGPassManager;
using llvm::SetVector;
using llvm::SmallPtrSetImpl;
using llvm::SmallVector;
using llvm::SmallVectorImpl;
using llvm::StringMap;
using llvm::Type;
using llvm::Use;
using llvm::Value;
using llvm::ValueToValueMap;
class MemoryAccess;
//===---------------------------------------------------------------------===//
extern bool UseInstructionNames;
// 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.
extern unsigned const MaxDisjunctsInDomain;
/// The different memory kinds used in Polly.
///
/// We distinguish between arrays and various scalar memory objects. We use
/// the term ``array'' to describe memory objects that consist of a set of
/// individual data elements arranged in a multi-dimensional grid. A scalar
/// memory object describes an individual data element and is used to model
/// the definition and uses of llvm::Values.
///
/// The polyhedral model does traditionally not reason about SSA values. To
/// reason about llvm::Values we model them "as if" they were zero-dimensional
/// memory objects, even though they were not actually allocated in (main)
/// memory. Memory for such objects is only alloca[ed] at CodeGeneration
/// time. To relate the memory slots used during code generation with the
/// llvm::Values they belong to the new names for these corresponding stack
/// slots are derived by appending suffixes (currently ".s2a" and ".phiops")
/// to the name of the original llvm::Value. To describe how def/uses are
/// modeled exactly we use these suffixes here as well.
///
/// There are currently four different kinds of memory objects:
enum class MemoryKind {
/// MemoryKind::Array: Models a one or multi-dimensional array
///
/// A memory object that can be described by a multi-dimensional array.
/// Memory objects of this type are used to model actual multi-dimensional
/// arrays as they exist in LLVM-IR, but they are also used to describe
/// other objects:
/// - A single data element allocated on the stack using 'alloca' is
/// modeled as a one-dimensional, single-element array.
/// - A single data element allocated as a global variable is modeled as
/// one-dimensional, single-element array.
/// - Certain multi-dimensional arrays with variable size, which in
/// LLVM-IR are commonly expressed as a single-dimensional access with a
/// complicated access function, are modeled as multi-dimensional
/// memory objects (grep for "delinearization").
Array,
/// MemoryKind::Value: Models an llvm::Value
///
/// Memory objects of type MemoryKind::Value are used to model the data flow
/// induced by llvm::Values. For each llvm::Value that is used across
/// BasicBlocks, one ScopArrayInfo object is created. A single memory WRITE
/// stores the llvm::Value at its definition into the memory object and at
/// each use of the llvm::Value (ignoring trivial intra-block uses) a
/// corresponding READ is added. For instance, the use/def chain of a
/// llvm::Value %V depicted below
/// ______________________
/// |DefBB: |
/// | %V = float op ... |
/// ----------------------
/// | |
/// _________________ _________________
/// |UseBB1: | |UseBB2: |
/// | use float %V | | use float %V |
/// ----------------- -----------------
///
/// is modeled as if the following memory accesses occurred:
///
/// __________________________
/// |entry: |
/// | %V.s2a = alloca float |
/// --------------------------
/// |
/// ___________________________________
/// |DefBB: |
/// | store %float %V, float* %V.s2a |
/// -----------------------------------
/// | |
/// ____________________________________ ___________________________________
/// |UseBB1: | |UseBB2: |
/// | %V.reload1 = load float* %V.s2a | | %V.reload2 = load float* %V.s2a|
/// | use float %V.reload1 | | use float %V.reload2 |
/// ------------------------------------ -----------------------------------
///
Value,
/// MemoryKind::PHI: Models PHI nodes within the SCoP
///
/// Besides the MemoryKind::Value memory object used to model the normal
/// llvm::Value dependences described above, PHI nodes require an additional
/// memory object of type MemoryKind::PHI to describe the forwarding of values
/// to
/// the PHI node.
///
/// As an example, a PHIInst instructions
///
/// %PHI = phi float [ %Val1, %IncomingBlock1 ], [ %Val2, %IncomingBlock2 ]
///
/// is modeled as if the accesses occurred this way:
///
/// _______________________________
/// |entry: |
/// | %PHI.phiops = alloca float |
/// -------------------------------
/// | |
/// __________________________________ __________________________________
/// |IncomingBlock1: | |IncomingBlock2: |
/// | ... | | ... |
/// | store float %Val1 %PHI.phiops | | store float %Val2 %PHI.phiops |
/// | br label % JoinBlock | | br label %JoinBlock |
/// ---------------------------------- ----------------------------------
/// \ /
/// \ /
/// _________________________________________
/// |JoinBlock: |
/// | %PHI = load float, float* PHI.phiops |
/// -----------------------------------------
///
/// Note that there can also be a scalar write access for %PHI if used in a
/// different BasicBlock, i.e. there can be a memory object %PHI.phiops as
/// well as a memory object %PHI.s2a.
PHI,
/// MemoryKind::ExitPHI: Models PHI nodes in the SCoP's exit block
///
/// For PHI nodes in the Scop's exit block a special memory object kind is
/// used. The modeling used is identical to MemoryKind::PHI, with the
/// exception
/// that there are no READs from these memory objects. The PHINode's
/// llvm::Value is treated as a value escaping the SCoP. WRITE accesses
/// write directly to the escaping value's ".s2a" alloca.
ExitPHI
};
/// Maps from a loop to the affine function expressing its backedge taken count.
/// The backedge taken count already enough to express iteration domain as we
/// only allow loops with canonical induction variable.
/// A canonical induction variable is:
/// an integer recurrence that starts at 0 and increments by one each time
/// through the loop.
using LoopBoundMapType = std::map<const Loop *, const SCEV *>;
using AccFuncVector = std::vector<std::unique_ptr<MemoryAccess>>;
/// A class to store information about arrays in the SCoP.
///
/// Objects are accessible via the ScoP, MemoryAccess or the id associated with
/// the MemoryAccess access function.
///
class ScopArrayInfo {
public:
/// Construct a ScopArrayInfo object.
///
/// @param BasePtr The array base pointer.
/// @param ElementType The type of the elements stored in the array.
/// @param IslCtx The isl context used to create the base pointer id.
/// @param DimensionSizes A vector containing the size of each dimension.
/// @param Kind The kind of the array object.
/// @param DL The data layout of the module.
/// @param S The scop this array object belongs to.
/// @param BaseName The optional name of this memory reference.
ScopArrayInfo(Value *BasePtr, Type *ElementType, isl::ctx IslCtx,
ArrayRef<const SCEV *> DimensionSizes, MemoryKind Kind,
const DataLayout &DL, Scop *S, const char *BaseName = nullptr);
/// Destructor to free the isl id of the base pointer.
~ScopArrayInfo();
/// Update the element type of the ScopArrayInfo object.
///
/// Memory accesses referencing this ScopArrayInfo object may use
/// different element sizes. This function ensures the canonical element type
/// stored is small enough to model accesses to the current element type as
/// well as to @p NewElementType.
///
/// @param NewElementType An element type that is used to access this array.
void updateElementType(Type *NewElementType);
/// Update the sizes of the ScopArrayInfo object.
///
/// A ScopArrayInfo object may be created without all outer dimensions being
/// available. This function is called when new memory accesses are added for
/// this ScopArrayInfo object. It verifies that sizes are compatible and adds
/// additional outer array dimensions, if needed.
///
/// @param Sizes A vector of array sizes where the rightmost array
/// sizes need to match the innermost array sizes already
/// defined in SAI.
/// @param CheckConsistency Update sizes, even if new sizes are inconsistent
/// with old sizes
bool updateSizes(ArrayRef<const SCEV *> Sizes, bool CheckConsistency = true);
/// Set the base pointer to @p BP.
void setBasePtr(Value *BP) { BasePtr = BP; }
/// Return the base pointer.
Value *getBasePtr() const { return BasePtr; }
// Set IsOnHeap to the value in parameter.
void setIsOnHeap(bool value) { IsOnHeap = value; }
/// For indirect accesses return the origin SAI of the BP, else null.
const ScopArrayInfo *getBasePtrOriginSAI() const { return BasePtrOriginSAI; }
/// The set of derived indirect SAIs for this origin SAI.
const SmallSetVector<ScopArrayInfo *, 2> &getDerivedSAIs() const {
return DerivedSAIs;
}
/// Return the number of dimensions.
unsigned getNumberOfDimensions() const {
if (Kind == MemoryKind::PHI || Kind == MemoryKind::ExitPHI ||
Kind == MemoryKind::Value)
return 0;
return DimensionSizes.size();
}
/// Return the size of dimension @p dim as SCEV*.
//
// Scalars do not have array dimensions and the first dimension of
// a (possibly multi-dimensional) array also does not carry any size
// information, in case the array is not newly created.
const SCEV *getDimensionSize(unsigned Dim) const {
assert(Dim < getNumberOfDimensions() && "Invalid dimension");
return DimensionSizes[Dim];
}
/// Return the size of dimension @p dim as isl::pw_aff.
//
// Scalars do not have array dimensions and the first dimension of
// a (possibly multi-dimensional) array also does not carry any size
// information, in case the array is not newly created.
isl::pw_aff getDimensionSizePw(unsigned Dim) const {
assert(Dim < getNumberOfDimensions() && "Invalid dimension");
return DimensionSizesPw[Dim];
}
/// Get the canonical element type of this array.
///
/// @returns The canonical element type of this array.
Type *getElementType() const { return ElementType; }
/// Get element size in bytes.
int getElemSizeInBytes() const;
/// Get the name of this memory reference.
std::string getName() const;
/// Return the isl id for the base pointer.
isl::id getBasePtrId() const;
/// Return what kind of memory this represents.
MemoryKind getKind() const { return Kind; }
/// Is this array info modeling an llvm::Value?
bool isValueKind() const { return Kind == MemoryKind::Value; }
/// Is this array info modeling special PHI node memory?
///
/// During code generation of PHI nodes, there is a need for two kinds of
/// virtual storage. The normal one as it is used for all scalar dependences,
/// where the result of the PHI node is stored and later loaded from as well
/// as a second one where the incoming values of the PHI nodes are stored
/// into and reloaded when the PHI is executed. As both memories use the
/// original PHI node as virtual base pointer, we have this additional
/// attribute to distinguish the PHI node specific array modeling from the
/// normal scalar array modeling.
bool isPHIKind() const { return Kind == MemoryKind::PHI; }
/// Is this array info modeling an MemoryKind::ExitPHI?
bool isExitPHIKind() const { return Kind == MemoryKind::ExitPHI; }
/// Is this array info modeling an array?
bool isArrayKind() const { return Kind == MemoryKind::Array; }
/// Is this array allocated on heap
///
/// This property is only relevant if the array is allocated by Polly instead
/// of pre-existing. If false, it is allocated using alloca instead malloca.
bool isOnHeap() const { return IsOnHeap; }
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
/// Dump a readable representation to stderr.
void dump() const;
#endif
/// Print a readable representation to @p OS.
///
/// @param SizeAsPwAff Print the size as isl::pw_aff
void print(raw_ostream &OS, bool SizeAsPwAff = false) const;
/// Access the ScopArrayInfo associated with an access function.
static const ScopArrayInfo *getFromAccessFunction(isl::pw_multi_aff PMA);
/// Access the ScopArrayInfo associated with an isl Id.
static const ScopArrayInfo *getFromId(isl::id Id);
/// Get the space of this array access.
isl::space getSpace() const;
/// If the array is read only
bool isReadOnly();
/// Verify that @p Array is compatible to this ScopArrayInfo.
///
/// Two arrays are compatible if their dimensionality, the sizes of their
/// dimensions, and their element sizes match.
///
/// @param Array The array to compare against.
///
/// @returns True, if the arrays are compatible, False otherwise.
bool isCompatibleWith(const ScopArrayInfo *Array) const;
private:
void addDerivedSAI(ScopArrayInfo *DerivedSAI) {
DerivedSAIs.insert(DerivedSAI);
}
/// For indirect accesses this is the SAI of the BP origin.
const ScopArrayInfo *BasePtrOriginSAI;
/// For origin SAIs the set of derived indirect SAIs.
SmallSetVector<ScopArrayInfo *, 2> DerivedSAIs;
/// The base pointer.
AssertingVH<Value> BasePtr;
/// The canonical element type of this array.
///
/// The canonical element type describes the minimal accessible element in
/// this array. Not all elements accessed, need to be of the very same type,
/// but the allocation size of the type of the elements loaded/stored from/to
/// this array needs to be a multiple of the allocation size of the canonical
/// type.
Type *ElementType;
/// The isl id for the base pointer.
isl::id Id;
/// True if the newly allocated array is on heap.
bool IsOnHeap = false;
/// The sizes of each dimension as SCEV*.
SmallVector<const SCEV *, 4> DimensionSizes;
/// The sizes of each dimension as isl::pw_aff.
SmallVector<isl::pw_aff, 4> DimensionSizesPw;
/// The type of this scop array info object.
///
/// We distinguish between SCALAR, PHI and ARRAY objects.
MemoryKind Kind;
/// The data layout of the module.
const DataLayout &DL;
/// The scop this SAI object belongs to.
Scop &S;
};
/// Represent memory accesses in statements.
class MemoryAccess {
friend class Scop;
friend class ScopStmt;
friend class ScopBuilder;
public:
/// The access type of a memory access
///
/// There are three kind of access types:
///
/// * A read access
///
/// A certain set of memory locations are read and may be used for internal
/// calculations.
///
/// * A must-write access
///
/// A certain set of memory locations is definitely written. The old value is
/// replaced by a newly calculated value. The old value is not read or used at
/// all.
///
/// * A may-write access
///
/// A certain set of memory locations may be written. The memory location may
/// contain a new value if there is actually a write or the old value may
/// remain, if no write happens.
enum AccessType {
READ = 0x1,
MUST_WRITE = 0x2,
MAY_WRITE = 0x3,
};
/// Reduction access type
///
/// Commutative and associative binary operations suitable for reductions
enum ReductionType {
RT_NONE, ///< Indicate no reduction at all
RT_ADD, ///< Addition
RT_MUL, ///< Multiplication
RT_BOR, ///< Bitwise Or
RT_BXOR, ///< Bitwise XOr
RT_BAND, ///< Bitwise And
};
using SubscriptsTy = SmallVector<const SCEV *, 4>;
private:
/// A unique identifier for this memory access.
///
/// The identifier is unique between all memory accesses belonging to the same
/// scop statement.
isl::id Id;
/// What is modeled by this MemoryAccess.
/// @see MemoryKind
MemoryKind Kind;
/// Whether it a reading or writing access, and if writing, whether it
/// is conditional (MAY_WRITE).
enum AccessType AccType;
/// Reduction type for reduction like accesses, RT_NONE otherwise
///
/// An access is reduction like if it is part of a load-store chain in which
/// both access the same memory location (use the same LLVM-IR value
/// as pointer reference). Furthermore, between the load and the store there
/// is exactly one binary operator which is known to be associative and
/// commutative.
///
/// TODO:
///
/// We can later lift the constraint that the same LLVM-IR value defines the
/// memory location to handle scops such as the following:
///
/// for i
/// for j
/// sum[i+j] = sum[i] + 3;
///
/// Here not all iterations access the same memory location, but iterations
/// for which j = 0 holds do. After lifting the equality check in ScopBuilder,
/// subsequent transformations do not only need check if a statement is
/// reduction like, but they also need to verify that that the reduction
/// property is only exploited for statement instances that load from and
/// store to the same data location. Doing so at dependence analysis time
/// could allow us to handle the above example.
ReductionType RedType = RT_NONE;
/// Parent ScopStmt of this access.
ScopStmt *Statement;
/// The domain under which this access is not modeled precisely.
///
/// The invalid domain for an access describes all parameter combinations
/// under which the statement looks to be executed but is in fact not because
/// some assumption/restriction makes the access invalid.
isl::set InvalidDomain;
// Properties describing the accessed array.
// TODO: It might be possible to move them to ScopArrayInfo.
// @{
/// The base address (e.g., A for A[i+j]).
///
/// The #BaseAddr of a memory access of kind MemoryKind::Array is the base
/// pointer of the memory access.
/// The #BaseAddr of a memory access of kind MemoryKind::PHI or
/// MemoryKind::ExitPHI is the PHI node itself.
/// The #BaseAddr of a memory access of kind MemoryKind::Value is the
/// instruction defining the value.
AssertingVH<Value> BaseAddr;
/// Type a single array element wrt. this access.
Type *ElementType;
/// Size of each dimension of the accessed array.
SmallVector<const SCEV *, 4> Sizes;
// @}
// Properties describing the accessed element.
// @{
/// The access instruction of this memory access.
///
/// For memory accesses of kind MemoryKind::Array the access instruction is
/// the Load or Store instruction performing the access.
///
/// For memory accesses of kind MemoryKind::PHI or MemoryKind::ExitPHI the
/// access instruction of a load access is the PHI instruction. The access
/// instruction of a PHI-store is the incoming's block's terminator
/// instruction.
///
/// For memory accesses of kind MemoryKind::Value the access instruction of a
/// load access is nullptr because generally there can be multiple
/// instructions in the statement using the same llvm::Value. The access
/// instruction of a write access is the instruction that defines the
/// llvm::Value.
Instruction *AccessInstruction = nullptr;
/// Incoming block and value of a PHINode.
SmallVector<std::pair<BasicBlock *, Value *>, 4> Incoming;
/// The value associated with this memory access.
///
/// - For array memory accesses (MemoryKind::Array) it is the loaded result
/// or the stored value. If the access instruction is a memory intrinsic it
/// the access value is also the memory intrinsic.
/// - For accesses of kind MemoryKind::Value it is the access instruction
/// itself.
/// - For accesses of kind MemoryKind::PHI or MemoryKind::ExitPHI it is the
/// PHI node itself (for both, READ and WRITE accesses).
///
AssertingVH<Value> AccessValue;
/// Are all the subscripts affine expression?
bool IsAffine = true;
/// Subscript expression for each dimension.
SubscriptsTy Subscripts;
/// Relation from statement instances to the accessed array elements.
///
/// In the common case this relation is a function that maps a set of loop
/// indices to the memory address from which a value is loaded/stored:
///
/// for i
/// for j
/// S: A[i + 3 j] = ...
///
/// => { S[i,j] -> A[i + 3j] }
///
/// In case the exact access function is not known, the access relation may
/// also be a one to all mapping { S[i,j] -> A[o] } describing that any
/// element accessible through A might be accessed.
///
/// In case of an access to a larger element belonging to an array that also
/// contains smaller elements, the access relation models the larger access
/// with multiple smaller accesses of the size of the minimal array element
/// type:
///
/// short *A;
///
/// for i
/// S: A[i] = *((double*)&A[4 * i]);
///
/// => { S[i] -> A[i]; S[i] -> A[o] : 4i <= o <= 4i + 3 }
isl::map AccessRelation;
/// Updated access relation read from JSCOP file.
isl::map NewAccessRelation;
// @}
isl::basic_map createBasicAccessMap(ScopStmt *Statement);
isl::set assumeNoOutOfBound();
/// Compute bounds on an over approximated access relation.
///
/// @param ElementSize The size of one element accessed.
void computeBoundsOnAccessRelation(unsigned ElementSize);
/// Get the original access function as read from IR.
isl::map getOriginalAccessRelation() const;
/// Return the space in which the access relation lives in.
isl::space getOriginalAccessRelationSpace() const;
/// Get the new access function imported or set by a pass
isl::map getNewAccessRelation() const;
/// Fold the memory access to consider parametric offsets
///
/// To recover memory accesses with array size parameters in the subscript
/// expression we post-process the delinearization results.
///
/// We would normally recover from an access A[exp0(i) * N + exp1(i)] into an
/// array A[][N] the 2D access A[exp0(i)][exp1(i)]. However, another valid
/// delinearization is A[exp0(i) - 1][exp1(i) + N] which - depending on the
/// range of exp1(i) - may be preferable. Specifically, for cases where we
/// know exp1(i) is negative, we want to choose the latter expression.
///
/// As we commonly do not have any information about the range of exp1(i),
/// we do not choose one of the two options, but instead create a piecewise
/// access function that adds the (-1, N) offsets as soon as exp1(i) becomes
/// negative. For a 2D array such an access function is created by applying
/// the piecewise map:
///
/// [i,j] -> [i, j] : j >= 0
/// [i,j] -> [i-1, j+N] : j < 0
///
/// We can generalize this mapping to arbitrary dimensions by applying this
/// piecewise mapping pairwise from the rightmost to the leftmost access
/// dimension. It would also be possible to cover a wider range by introducing
/// more cases and adding multiple of Ns to these cases. However, this has
/// not yet been necessary.
/// The introduction of different cases necessarily complicates the memory
/// access function, but cases that can be statically proven to not happen
/// will be eliminated later on.
void foldAccessRelation();
/// Create the access relation for the underlying memory intrinsic.
void buildMemIntrinsicAccessRelation();
/// Assemble the access relation from all available information.
///
/// In particular, used the information passes in the constructor and the
/// parent ScopStmt set by setStatment().
///
/// @param SAI Info object for the accessed array.
void buildAccessRelation(const ScopArrayInfo *SAI);
/// Carry index overflows of dimensions with constant size to the next higher
/// dimension.
///
/// For dimensions that have constant size, modulo the index by the size and
/// add up the carry (floored division) to the next higher dimension. This is
/// how overflow is defined in row-major order.
/// It happens e.g. when ScalarEvolution computes the offset to the base
/// pointer and would algebraically sum up all lower dimensions' indices of
/// constant size.
///
/// Example:
/// float (*A)[4];
/// A[1][6] -> A[2][2]
void wrapConstantDimensions();
public:
/// Create a new MemoryAccess.
///
/// @param Stmt The parent statement.
/// @param AccessInst The instruction doing the access.
/// @param BaseAddr The accessed array's address.
/// @param ElemType The type of the accessed array elements.
/// @param AccType Whether read or write access.
/// @param IsAffine Whether the subscripts are affine expressions.
/// @param Kind The kind of memory accessed.
/// @param Subscripts Subscript expressions
/// @param Sizes Dimension lengths of the accessed array.
MemoryAccess(ScopStmt *Stmt, Instruction *AccessInst, AccessType AccType,
Value *BaseAddress, Type *ElemType, bool Affine,
ArrayRef<const SCEV *> Subscripts, ArrayRef<const SCEV *> Sizes,
Value *AccessValue, MemoryKind Kind);
/// Create a new MemoryAccess that corresponds to @p AccRel.
///
/// Along with @p Stmt and @p AccType it uses information about dimension
/// lengths of the accessed array, the type of the accessed array elements,
/// the name of the accessed array that is derived from the object accessible
/// via @p AccRel.
///
/// @param Stmt The parent statement.
/// @param AccType Whether read or write access.
/// @param AccRel The access relation that describes the memory access.
MemoryAccess(ScopStmt *Stmt, AccessType AccType, isl::map AccRel);
MemoryAccess(const MemoryAccess &) = delete;
MemoryAccess &operator=(const MemoryAccess &) = delete;
~MemoryAccess();
/// Add a new incoming block/value pairs for this PHI/ExitPHI access.
///
/// @param IncomingBlock The PHI's incoming block.
/// @param IncomingValue The value when reaching the PHI from the @p
/// IncomingBlock.
void addIncoming(BasicBlock *IncomingBlock, Value *IncomingValue) {
assert(!isRead());
assert(isAnyPHIKind());
Incoming.emplace_back(std::make_pair(IncomingBlock, IncomingValue));
}
/// Return the list of possible PHI/ExitPHI values.
///
/// After code generation moves some PHIs around during region simplification,
/// we cannot reliably locate the original PHI node and its incoming values
/// anymore. For this reason we remember these explicitly for all PHI-kind
/// accesses.
ArrayRef<std::pair<BasicBlock *, Value *>> getIncoming() const {
assert(isAnyPHIKind());
return Incoming;
}
/// Get the type of a memory access.
enum AccessType getType() { return AccType; }
/// Is this a reduction like access?
bool isReductionLike() const { return RedType != RT_NONE; }
/// Is this a read memory access?
bool isRead() const { return AccType == MemoryAccess::READ; }
/// Is this a must-write memory access?
bool isMustWrite() const { return AccType == MemoryAccess::MUST_WRITE; }
/// Is this a may-write memory access?
bool isMayWrite() const { return AccType == MemoryAccess::MAY_WRITE; }
/// Is this a write memory access?
bool isWrite() const { return isMustWrite() || isMayWrite(); }
/// Is this a memory intrinsic access (memcpy, memset, memmove)?
bool isMemoryIntrinsic() const {
return isa<MemIntrinsic>(getAccessInstruction());
}
/// Check if a new access relation was imported or set by a pass.
bool hasNewAccessRelation() const { return !NewAccessRelation.is_null(); }
/// Return the newest access relation of this access.
///
/// There are two possibilities:
/// 1) The original access relation read from the LLVM-IR.
/// 2) A new access relation imported from a json file or set by another
/// pass (e.g., for privatization).
///
/// As 2) is by construction "newer" than 1) we return the new access
/// relation if present.
///
isl::map getLatestAccessRelation() const {
return hasNewAccessRelation() ? getNewAccessRelation()
: getOriginalAccessRelation();
}
/// Old name of getLatestAccessRelation().
isl::map getAccessRelation() const { return getLatestAccessRelation(); }
/// Get an isl map describing the memory address accessed.
///
/// In most cases the memory address accessed is well described by the access
/// relation obtained with getAccessRelation. However, in case of arrays
/// accessed with types of different size the access relation maps one access
/// to multiple smaller address locations. This method returns an isl map that
/// relates each dynamic statement instance to the unique memory location
/// that is loaded from / stored to.
///
/// For an access relation { S[i] -> A[o] : 4i <= o <= 4i + 3 } this method
/// will return the address function { S[i] -> A[4i] }.
///
/// @returns The address function for this memory access.
isl::map getAddressFunction() const;
/// Return the access relation after the schedule was applied.
isl::pw_multi_aff
applyScheduleToAccessRelation(isl::union_map Schedule) const;
/// Get an isl string representing the access function read from IR.
std::string getOriginalAccessRelationStr() const;
/// Get an isl string representing a new access function, if available.
std::string getNewAccessRelationStr() const;
/// Get an isl string representing the latest access relation.
std::string getAccessRelationStr() const;
/// Get the original base address of this access (e.g. A for A[i+j]) when
/// detected.
///
/// This address may differ from the base address referenced by the original
/// ScopArrayInfo to which this array belongs, as this memory access may
/// have been canonicalized to a ScopArrayInfo which has a different but
/// identically-valued base pointer in case invariant load hoisting is
/// enabled.
Value *getOriginalBaseAddr() const { return BaseAddr; }
/// Get the detection-time base array isl::id for this access.
isl::id getOriginalArrayId() const;
/// Get the base array isl::id for this access, modifiable through
/// setNewAccessRelation().
isl::id getLatestArrayId() const;
/// Old name of getOriginalArrayId().
isl::id getArrayId() const { return getOriginalArrayId(); }
/// Get the detection-time ScopArrayInfo object for the base address.
const ScopArrayInfo *getOriginalScopArrayInfo() const;
/// Get the ScopArrayInfo object for the base address, or the one set
/// by setNewAccessRelation().
const ScopArrayInfo *getLatestScopArrayInfo() const;
/// Legacy name of getOriginalScopArrayInfo().
const ScopArrayInfo *getScopArrayInfo() const {
return getOriginalScopArrayInfo();
}
/// Return a string representation of the access's reduction type.
const std::string getReductionOperatorStr() const;
/// Return a string representation of the reduction type @p RT.
static const std::string getReductionOperatorStr(ReductionType RT);
/// Return the element type of the accessed array wrt. this access.
Type *getElementType() const { return ElementType; }
/// Return the access value of this memory access.
Value *getAccessValue() const { return AccessValue; }
/// Return llvm::Value that is stored by this access, if available.
///
/// PHI nodes may not have a unique value available that is stored, as in
/// case of region statements one out of possibly several llvm::Values
/// might be stored. In this case nullptr is returned.
Value *tryGetValueStored() {
assert(isWrite() && "Only write statement store values");
if (isAnyPHIKind()) {
if (Incoming.size() == 1)
return Incoming[0].second;
return nullptr;
}
return AccessValue;
}
/// Return the access instruction of this memory access.
Instruction *getAccessInstruction() const { return AccessInstruction; }
/// Return an iterator range containing the subscripts.
iterator_range<SubscriptsTy::const_iterator> subscripts() const {
return make_range(Subscripts.begin(), Subscripts.end());
}
/// Return the number of access function subscript.
unsigned getNumSubscripts() const { return Subscripts.size(); }
/// Return the access function subscript in the dimension @p Dim.
const SCEV *getSubscript(unsigned Dim) const { return Subscripts[Dim]; }
/// Compute the isl representation for the SCEV @p E wrt. this access.
///
/// Note that this function will also adjust the invalid context accordingly.
isl::pw_aff getPwAff(const SCEV *E);
/// Get the invalid domain for this access.
isl::set getInvalidDomain() const { return InvalidDomain; }
/// Get the invalid context for this access.
isl::set getInvalidContext() const { return getInvalidDomain().params(); }
/// Get the stride of this memory access in the specified Schedule. Schedule
/// is a map from the statement to a schedule where the innermost dimension is
/// the dimension of the innermost loop containing the statement.
isl::set getStride(isl::map Schedule) const;
/// Is the stride of the access equal to a certain width? Schedule is a map
/// from the statement to a schedule where the innermost dimension is the
/// dimension of the innermost loop containing the statement.
bool isStrideX(isl::map Schedule, int StrideWidth) const;
/// Is consecutive memory accessed for a given statement instance set?
/// Schedule is a map from the statement to a schedule where the innermost
/// dimension is the dimension of the innermost loop containing the
/// statement.
bool isStrideOne(isl::map Schedule) const;
/// Is always the same memory accessed for a given statement instance set?
/// Schedule is a map from the statement to a schedule where the innermost
/// dimension is the dimension of the innermost loop containing the
/// statement.
bool isStrideZero(isl::map Schedule) const;
/// Return the kind when this access was first detected.
MemoryKind getOriginalKind() const {
assert(!getOriginalScopArrayInfo() /* not yet initialized */ ||
getOriginalScopArrayInfo()->getKind() == Kind);
return Kind;
}
/// Return the kind considering a potential setNewAccessRelation.
MemoryKind getLatestKind() const {
return getLatestScopArrayInfo()->getKind();
}
/// Whether this is an access of an explicit load or store in the IR.
bool isOriginalArrayKind() const {
return getOriginalKind() == MemoryKind::Array;
}
/// Whether storage memory is either an custom .s2a/.phiops alloca
/// (false) or an existing pointer into an array (true).
bool isLatestArrayKind() const {
return getLatestKind() == MemoryKind::Array;
}
/// Old name of isOriginalArrayKind.
bool isArrayKind() const { return isOriginalArrayKind(); }
/// Whether this access is an array to a scalar memory object, without
/// considering changes by setNewAccessRelation.
///
/// Scalar accesses are accesses to MemoryKind::Value, MemoryKind::PHI or
/// MemoryKind::ExitPHI.
bool isOriginalScalarKind() const {
return getOriginalKind() != MemoryKind::Array;
}
/// Whether this access is an array to a scalar memory object, also
/// considering changes by setNewAccessRelation.
bool isLatestScalarKind() const {
return getLatestKind() != MemoryKind::Array;
}
/// Old name of isOriginalScalarKind.
bool isScalarKind() const { return isOriginalScalarKind(); }
/// Was this MemoryAccess detected as a scalar dependences?
bool isOriginalValueKind() const {
return getOriginalKind() == MemoryKind::Value;
}
/// Is this MemoryAccess currently modeling scalar dependences?
bool isLatestValueKind() const {
return getLatestKind() == MemoryKind::Value;
}
/// Old name of isOriginalValueKind().
bool isValueKind() const { return isOriginalValueKind(); }
/// Was this MemoryAccess detected as a special PHI node access?
bool isOriginalPHIKind() const {
return getOriginalKind() == MemoryKind::PHI;
}
/// Is this MemoryAccess modeling special PHI node accesses, also
/// considering a potential change by setNewAccessRelation?
bool isLatestPHIKind() const { return getLatestKind() == MemoryKind::PHI; }
/// Old name of isOriginalPHIKind.
bool isPHIKind() const { return isOriginalPHIKind(); }
/// Was this MemoryAccess detected as the accesses of a PHI node in the
/// SCoP's exit block?
bool isOriginalExitPHIKind() const {
return getOriginalKind() == MemoryKind::ExitPHI;
}
/// Is this MemoryAccess modeling the accesses of a PHI node in the
/// SCoP's exit block? Can be changed to an array access using
/// setNewAccessRelation().
bool isLatestExitPHIKind() const {
return getLatestKind() == MemoryKind::ExitPHI;
}
/// Old name of isOriginalExitPHIKind().
bool isExitPHIKind() const { return isOriginalExitPHIKind(); }
/// Was this access detected as one of the two PHI types?
bool isOriginalAnyPHIKind() const {
return isOriginalPHIKind() || isOriginalExitPHIKind();
}
/// Does this access originate from one of the two PHI types? Can be
/// changed to an array access using setNewAccessRelation().
bool isLatestAnyPHIKind() const {
return isLatestPHIKind() || isLatestExitPHIKind();
}
/// Old name of isOriginalAnyPHIKind().
bool isAnyPHIKind() const { return isOriginalAnyPHIKind(); }
/// Get the statement that contains this memory access.
ScopStmt *getStatement() const { return Statement; }
/// Get the reduction type of this access
ReductionType getReductionType() const { return RedType; }
/// Update the original access relation.
///
/// We need to update the original access relation during scop construction,
/// when unifying the memory accesses that access the same scop array info
/// object. After the scop has been constructed, the original access relation
/// should not be changed any more. Instead setNewAccessRelation should
/// be called.
void setAccessRelation(isl::map AccessRelation);
/// Set the updated access relation read from JSCOP file.
void setNewAccessRelation(isl::map NewAccessRelation);
/// Return whether the MemoryyAccess is a partial access. That is, the access
/// is not executed in some instances of the parent statement's domain.
bool isLatestPartialAccess() const;
/// Mark this a reduction like access
void markAsReductionLike(ReductionType RT) { RedType = RT; }
/// Align the parameters in the access relation to the scop context
void realignParams();
/// Update the dimensionality of the memory access.
///
/// During scop construction some memory accesses may not be constructed with
/// their full dimensionality, but outer dimensions may have been omitted if
/// they took the value 'zero'. By updating the dimensionality of the
/// statement we add additional zero-valued dimensions to match the
/// dimensionality of the ScopArrayInfo object that belongs to this memory
/// access.
void updateDimensionality();
/// Get identifier for the memory access.
///
/// This identifier is unique for all accesses that belong to the same scop
/// statement.
isl::id getId() const;
/// Print the MemoryAccess.
///
/// @param OS The output stream the MemoryAccess is printed to.
void print(raw_ostream &OS) const;
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
/// Print the MemoryAccess to stderr.
void dump() const;
#endif
/// Is the memory access affine?
bool isAffine() const { return IsAffine; }
};
raw_ostream &operator<<(raw_ostream &OS, MemoryAccess::ReductionType RT);
/// Ordered list type to hold accesses.
using MemoryAccessList = std::forward_list<MemoryAccess *>;
/// Helper structure for invariant memory accesses.
struct InvariantAccess {
/// The memory access that is (partially) invariant.
MemoryAccess *MA;
/// The context under which the access is not invariant.
isl::set NonHoistableCtx;
};
/// Ordered container type to hold invariant accesses.
using InvariantAccessesTy = SmallVector<InvariantAccess, 8>;
/// Type for equivalent invariant accesses and their domain context.
struct InvariantEquivClassTy {
/// The pointer that identifies this equivalence class
const SCEV *IdentifyingPointer;
/// Memory accesses now treated invariant
///
/// These memory accesses access the pointer location that identifies
/// this equivalence class. They are treated as invariant and hoisted during
/// code generation.
MemoryAccessList InvariantAccesses;
/// The execution context under which the memory location is accessed
///
/// It is the union of the execution domains of the memory accesses in the
/// InvariantAccesses list.
isl::set ExecutionContext;
/// The type of the invariant access
///
/// It is used to differentiate between differently typed invariant loads from
/// the same location.
Type *AccessType;
};
/// Type for invariant accesses equivalence classes.
using InvariantEquivClassesTy = SmallVector<InvariantEquivClassTy, 8>;
/// Statement of the Scop
///
/// A Scop statement represents an instruction in the Scop.
///
/// It is further described by its iteration domain, its schedule and its data
/// accesses.
/// At the moment every statement represents a single basic block of LLVM-IR.
class ScopStmt {
friend class ScopBuilder;
public:
/// Create the ScopStmt from a BasicBlock.
ScopStmt(Scop &parent, BasicBlock &bb, StringRef Name, Loop *SurroundingLoop,
std::vector<Instruction *> Instructions);
/// Create an overapproximating ScopStmt for the region @p R.
///
/// @param EntryBlockInstructions The list of instructions that belong to the
/// entry block of the region statement.
/// Instructions are only tracked for entry
/// blocks for now. We currently do not allow
/// to modify the instructions of blocks later
/// in the region statement.
ScopStmt(Scop &parent, Region &R, StringRef Name, Loop *SurroundingLoop,
std::vector<Instruction *> EntryBlockInstructions);
/// Create a copy statement.
///
/// @param Stmt The parent statement.
/// @param SourceRel The source location.
/// @param TargetRel The target location.
/// @param Domain The original domain under which the copy statement would
/// be executed.
ScopStmt(Scop &parent, isl::map SourceRel, isl::map TargetRel,
isl::set Domain);
ScopStmt(const ScopStmt &) = delete;
const ScopStmt &operator=(const ScopStmt &) = delete;
~ScopStmt();
private:
/// Polyhedral description
//@{
/// The Scop containing this ScopStmt.
Scop &Parent;
/// The domain under which this statement is not modeled precisely.
///
/// The invalid domain for a statement describes all parameter combinations
/// under which the statement looks to be executed but is in fact not because
/// some assumption/restriction makes the statement/scop invalid.
isl::set InvalidDomain;
/// The iteration domain describes the set of iterations for which this
/// statement is executed.
///
/// Example:
/// for (i = 0; i < 100 + b; ++i)
/// for (j = 0; j < i; ++j)
/// S(i,j);
///
/// 'S' is executed for different values of i and j. A vector of all
/// induction variables around S (i, j) is called iteration vector.
/// The domain describes the set of possible iteration vectors.
///
/// In this case it is:
///
/// Domain: 0 <= i <= 100 + b
/// 0 <= j <= i
///
/// A pair of statement and iteration vector (S, (5,3)) is called statement
/// instance.
isl::set Domain;
/// The memory accesses of this statement.
///
/// The only side effects of a statement are its memory accesses.
using MemoryAccessVec = llvm::SmallVector<MemoryAccess *, 8>;
MemoryAccessVec MemAccs;
/// Mapping from instructions to (scalar) memory accesses.
DenseMap<const Instruction *, MemoryAccessList> InstructionToAccess;
/// The set of values defined elsewhere required in this ScopStmt and
/// their MemoryKind::Value READ MemoryAccesses.
DenseMap<Value *, MemoryAccess *> ValueReads;
/// The set of values defined in this ScopStmt that are required
/// elsewhere, mapped to their MemoryKind::Value WRITE MemoryAccesses.
DenseMap<Instruction *, MemoryAccess *> ValueWrites;
/// Map from PHI nodes to its incoming value when coming from this
/// statement.
///
/// Non-affine subregions can have multiple exiting blocks that are incoming
/// blocks of the PHI nodes. This map ensures that there is only one write
/// operation for the complete subregion. A PHI selecting the relevant value
/// will be inserted.
DenseMap<PHINode *, MemoryAccess *> PHIWrites;
/// Map from PHI nodes to its read access in this statement.
DenseMap<PHINode *, MemoryAccess *> PHIReads;
//@}
/// A SCoP statement represents either a basic block (affine/precise case) or
/// a whole region (non-affine case).
///
/// Only one of the following two members will therefore be set and indicate
/// which kind of statement this is.
///
///{
/// The BasicBlock represented by this statement (in the affine case).
BasicBlock *BB = nullptr;
/// The region represented by this statement (in the non-affine case).
Region *R = nullptr;
///}
/// The isl AST build for the new generated AST.
isl::ast_build Build;
SmallVector<Loop *, 4> NestLoops;
std::string BaseName;
/// The closest loop that contains this statement.
Loop *SurroundingLoop;
/// Vector for Instructions in this statement.
std::vector<Instruction *> Instructions;
/// Remove @p MA from dictionaries pointing to them.
void removeAccessData(MemoryAccess *MA);
public:
/// Get an isl_ctx pointer.
isl::ctx getIslCtx() const;
/// Get the iteration domain of this ScopStmt.
///
/// @return The iteration domain of this ScopStmt.
isl::set getDomain() const;
/// Get the space of the iteration domain
///
/// @return The space of the iteration domain
isl::space getDomainSpace() const;
/// Get the id of the iteration domain space
///
/// @return The id of the iteration domain space
isl::id getDomainId() const;
/// Get an isl string representing this domain.
std::string getDomainStr() const;
/// Get the schedule function of this ScopStmt.
///
/// @return The schedule function of this ScopStmt, if it does not contain
/// extension nodes, and nullptr, otherwise.
isl::map getSchedule() const;
/// Get an isl string representing this schedule.
///
/// @return An isl string representing this schedule, if it does not contain
/// extension nodes, and an empty string, otherwise.
std::string getScheduleStr() const;
/// Get the invalid domain for this statement.
isl::set getInvalidDomain() const { return InvalidDomain; }
/// Get the invalid context for this statement.
isl::set getInvalidContext() const { return getInvalidDomain().params(); }
/// Set the invalid context for this statement to @p ID.
void setInvalidDomain(isl::set ID);
/// Get the BasicBlock represented by this ScopStmt (if any).
///
/// @return The BasicBlock represented by this ScopStmt, or null if the
/// statement represents a region.
BasicBlock *getBasicBlock() const { return BB; }
/// Return true if this statement represents a single basic block.
bool isBlockStmt() const { return BB != nullptr; }
/// Return true if this is a copy statement.
bool isCopyStmt() const { return BB == nullptr && R == nullptr; }
/// Get the region represented by this ScopStmt (if any).
///
/// @return The region represented by this ScopStmt, or null if the statement
/// represents a basic block.
Region *getRegion() const { return R; }
/// Return true if this statement represents a whole region.
bool isRegionStmt() const { return R != nullptr; }
/// Return a BasicBlock from this statement.
///
/// For block statements, it returns the BasicBlock itself. For subregion
/// statements, return its entry block.
BasicBlock *getEntryBlock() const;
/// Return whether @p L is boxed within this statement.
bool contains(const Loop *L) const {
// Block statements never contain loops.
if (isBlockStmt())
return false;
return getRegion()->contains(L);
}
/// Return whether this statement represents @p BB.
bool represents(BasicBlock *BB) const {
if (isCopyStmt())
return false;
if (isBlockStmt())
return BB == getBasicBlock();
return getRegion()->contains(BB);
}
/// Return whether this statement contains @p Inst.
bool contains(Instruction *Inst) const {
if (!Inst)
return false;
if (isBlockStmt())
return std::find(Instructions.begin(), Instructions.end(), Inst) !=
Instructions.end();
return represents(Inst->getParent());
}
/// Return the closest innermost loop that contains this statement, but is not
/// contained in it.
///
/// For block statement, this is just the loop that contains the block. Region
/// statements can contain boxed loops, so getting the loop of one of the
/// region's BBs might return such an inner loop. For instance, the region's
/// entry could be a header of a loop, but the region might extend to BBs
/// after the loop exit. Similarly, the region might only contain parts of the
/// loop body and still include the loop header.
///
/// Most of the time the surrounding loop is the top element of #NestLoops,
/// except when it is empty. In that case it return the loop that the whole
/// SCoP is contained in. That can be nullptr if there is no such loop.
Loop *getSurroundingLoop() const {
assert(!isCopyStmt() &&
"No surrounding loop for artificially created statements");
return SurroundingLoop;
}
/// Return true if this statement does not contain any accesses.
bool isEmpty() const { return MemAccs.empty(); }
/// Find all array accesses for @p Inst.
///
/// @param Inst The instruction accessing an array.
///
/// @return A list of array accesses (MemoryKind::Array) accessed by @p Inst.
/// If there is no such access, it returns nullptr.
const MemoryAccessList *
lookupArrayAccessesFor(const Instruction *Inst) const {
auto It = InstructionToAccess.find(Inst);
if (It == InstructionToAccess.end())
return nullptr;
if (It->second.empty())
return nullptr;
return &It->second;
}
/// Return the only array access for @p Inst, if existing.
///
/// @param Inst The instruction for which to look up the access.
/// @returns The unique array memory access related to Inst or nullptr if
/// no array access exists
MemoryAccess *getArrayAccessOrNULLFor(const Instruction *Inst) const {
auto It = InstructionToAccess.find(Inst);
if (It == InstructionToAccess.end())
return nullptr;
MemoryAccess *ArrayAccess = nullptr;
for (auto Access : It->getSecond()) {
if (!Access->isArrayKind())
continue;
assert(!ArrayAccess && "More then one array access for instruction");
ArrayAccess = Access;
}
return ArrayAccess;
}
/// Return the only array access for @p Inst.
///
/// @param Inst The instruction for which to look up the access.
/// @returns The unique array memory access related to Inst.
MemoryAccess &getArrayAccessFor(const Instruction *Inst) const {
MemoryAccess *ArrayAccess = getArrayAccessOrNULLFor(Inst);
assert(ArrayAccess && "No array access found for instruction!");
return *ArrayAccess;
}
/// Return the MemoryAccess that writes the value of an instruction
/// defined in this statement, or nullptr if not existing, respectively
/// not yet added.
MemoryAccess *lookupValueWriteOf(Instruction *Inst) const {
assert((isRegionStmt() && R->contains(Inst)) ||
(!isRegionStmt() && Inst->getParent() == BB));
return ValueWrites.lookup(Inst);
}
/// Return the MemoryAccess that reloads a value, or nullptr if not
/// existing, respectively not yet added.
MemoryAccess *lookupValueReadOf(Value *Inst) const {
return ValueReads.lookup(Inst);
}
/// Return the MemoryAccess that loads a PHINode value, or nullptr if not
/// existing, respectively not yet added.
MemoryAccess *lookupPHIReadOf(PHINode *PHI) const {
return PHIReads.lookup(PHI);
}
/// Return the PHI write MemoryAccess for the incoming values from any
/// basic block in this ScopStmt, or nullptr if not existing,
/// respectively not yet added.
MemoryAccess *lookupPHIWriteOf(PHINode *PHI) const {
assert(isBlockStmt() || R->getExit() == PHI->getParent());
return PHIWrites.lookup(PHI);
}
/// Return the input access of the value, or null if no such MemoryAccess
/// exists.
///
/// The input access is the MemoryAccess that makes an inter-statement value
/// available in this statement by reading it at the start of this statement.
/// This can be a MemoryKind::Value if defined in another statement or a
/// MemoryKind::PHI if the value is a PHINode in this statement.
MemoryAccess *lookupInputAccessOf(Value *Val) const {
if (isa<PHINode>(Val))
if (auto InputMA = lookupPHIReadOf(cast<PHINode>(Val))) {
assert(!lookupValueReadOf(Val) && "input accesses must be unique; a "
"statement cannot read a .s2a and "
".phiops simultaneously");
return InputMA;
}
if (auto *InputMA = lookupValueReadOf(Val))
return InputMA;
return nullptr;
}
/// Add @p Access to this statement's list of accesses.
///
/// @param Access The access to add.
/// @param Prepend If true, will add @p Access before all other instructions
/// (instead of appending it).
void addAccess(MemoryAccess *Access, bool Preprend = false);
/// Remove a MemoryAccess from this statement.
///
/// Note that scalar accesses that are caused by MA will
/// be eliminated too.
void removeMemoryAccess(MemoryAccess *MA);
/// Remove @p MA from this statement.
///
/// In contrast to removeMemoryAccess(), no other access will be eliminated.
///
/// @param MA The MemoryAccess to be removed.
/// @param AfterHoisting If true, also remove from data access lists.
/// These lists are filled during
/// ScopBuilder::buildAccessRelations. Therefore, if this
/// method is called before buildAccessRelations, false
/// must be passed.
void removeSingleMemoryAccess(MemoryAccess *MA, bool AfterHoisting = true);
using iterator = MemoryAccessVec::iterator;
using const_iterator = MemoryAccessVec::const_iterator;
iterator begin() { return MemAccs.begin(); }
iterator end() { return MemAccs.end(); }
const_iterator begin() const { return MemAccs.begin(); }
const_iterator end() const { return MemAccs.end(); }
size_t size() const { return MemAccs.size(); }
unsigned getNumIterators() const;
Scop *getParent() { return &Parent; }
const Scop *getParent() const { return &Parent; }
const std::vector<Instruction *> &getInstructions() const {
return Instructions;
}
/// Set the list of instructions for this statement. It replaces the current
/// list.
void setInstructions(ArrayRef<Instruction *> Range) {
Instructions.assign(Range.begin(), Range.end());
}
std::vector<Instruction *>::const_iterator insts_begin() const {
return Instructions.begin();
}
std::vector<Instruction *>::const_iterator insts_end() const {
return Instructions.end();
}
/// The range of instructions in this statement.
iterator_range<std::vector<Instruction *>::const_iterator> insts() const {
return {insts_begin(), insts_end()};
}
/// Insert an instruction before all other instructions in this statement.
void prependInstruction(Instruction *Inst) {
Instructions.insert(Instructions.begin(), Inst);
}
const char *getBaseName() const;
/// Set the isl AST build.
void setAstBuild(isl::ast_build B) { Build = B; }
/// Get the isl AST build.
isl::ast_build getAstBuild() const { return Build; }
/// Restrict the domain of the statement.
///
/// @param NewDomain The new statement domain.
void restrictDomain(isl::set NewDomain);
/// Get the loop for a dimension.
///
/// @param Dimension The dimension of the induction variable
/// @return The loop at a certain dimension.
Loop *getLoopForDimension(unsigned Dimension) const;
/// Align the parameters in the statement to the scop context
void realignParams();
/// Print the ScopStmt.
///
/// @param OS The output stream the ScopStmt is printed to.
/// @param PrintInstructions Whether to print the statement's instructions as
/// well.
void print(raw_ostream &OS, bool PrintInstructions) const;
/// Print the instructions in ScopStmt.
///
void printInstructions(raw_ostream &OS) const;
/// Check whether there is a value read access for @p V in this statement, and
/// if not, create one.
///
/// This allows to add MemoryAccesses after the initial creation of the Scop
/// by ScopBuilder.
///
/// @return The already existing or newly created MemoryKind::Value READ
/// MemoryAccess.
///
/// @see ScopBuilder::ensureValueRead(Value*,ScopStmt*)
MemoryAccess *ensureValueRead(Value *V);
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
/// Print the ScopStmt to stderr.
void dump() const;
#endif
};
/// Print ScopStmt S to raw_ostream OS.
raw_ostream &operator<<(raw_ostream &OS, const ScopStmt &S);
/// 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,
Instruction *TI, Loop *L, __isl_keep isl_set *Domain,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
SmallVectorImpl<__isl_give isl_set *> &ConditionSets);
/// 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);
/// 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, Instruction *TI, Loop *L,
__isl_keep isl_set *Domain,
DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
SmallVectorImpl<__isl_give isl_set *> &ConditionSets);
/// Static Control Part
///
/// A Scop is the polyhedral representation of a control flow region detected
/// by the Scop detection. It is generated by translating the LLVM-IR and
/// abstracting its effects.
///
/// A Scop consists of a set of:
///
/// * A set of statements executed in the Scop.
///
/// * A set of global parameters
/// Those parameters are scalar integer values, which are constant during
/// execution.
///
/// * A context
/// This context contains information about the values the parameters
/// can take and relations between different parameters.
class Scop {
public:
/// Type to represent a pair of minimal/maximal access to an array.
using MinMaxAccessTy = std::pair<isl::pw_multi_aff, isl::pw_multi_aff>;
/// Vector of minimal/maximal accesses to different arrays.
using MinMaxVectorTy = SmallVector<MinMaxAccessTy, 4>;
/// Pair of minimal/maximal access vectors representing
/// read write and read only accesses
using MinMaxVectorPairTy = std::pair<MinMaxVectorTy, MinMaxVectorTy>;
/// Vector of pair of minimal/maximal access vectors representing
/// non read only and read only accesses for each alias group.
using MinMaxVectorPairVectorTy = SmallVector<MinMaxVectorPairTy, 4>;
private:
friend class ScopBuilder;
/// Isl context.
///
/// We need a shared_ptr with reference counter to delete the context when all
/// isl objects are deleted. We will distribute the shared_ptr to all objects
/// that use the context to create isl objects, and increase the reference
/// counter. By doing this, we guarantee that the context is deleted when we
/// delete the last object that creates isl objects with the context. This
/// declaration needs to be the first in class to gracefully destroy all isl
/// objects before the context.
std::shared_ptr<isl_ctx> IslCtx;
ScalarEvolution *SE;
DominatorTree *DT;
/// The underlying Region.
Region &R;
/// The name of the SCoP (identical to the regions name)
Optional<std::string> name;
// Access functions of the SCoP.
//
// This owns all the MemoryAccess objects of the Scop created in this pass.
AccFuncVector AccessFunctions;
/// Flag to indicate that the scheduler actually optimized the SCoP.
bool IsOptimized = false;
/// True if the underlying region has a single exiting block.
bool HasSingleExitEdge;
/// Flag to remember if the SCoP contained an error block or not.
bool HasErrorBlock = false;
/// Max loop depth.
unsigned MaxLoopDepth = 0;
/// Number of copy statements.
unsigned CopyStmtsNum = 0;
/// Flag to indicate if the Scop is to be skipped.
bool SkipScop = false;
using StmtSet = std::list<ScopStmt>;
/// The statements in this Scop.
StmtSet Stmts;
/// Parameters of this Scop
ParameterSetTy Parameters;
/// Mapping from parameters to their ids.
DenseMap<const SCEV *, isl::id> ParameterIds;
/// The context of the SCoP created during SCoP detection.
ScopDetection::DetectionContext &DC;
/// OptimizationRemarkEmitter object for displaying diagnostic remarks
OptimizationRemarkEmitter &ORE;
/// A map from basic blocks to vector of SCoP statements. Currently this
/// vector comprises only of a single statement.
DenseMap<BasicBlock *, std::vector<ScopStmt *>> StmtMap;
/// A map from instructions to SCoP statements.
DenseMap<Instruction *, ScopStmt *> InstStmtMap;
/// A map from basic blocks to their domains.
DenseMap<BasicBlock *, isl::set> DomainMap;
/// Constraints on parameters.
isl::set Context;
/// The affinator used to translate SCEVs to isl expressions.
SCEVAffinator Affinator;
using ArrayInfoMapTy =
std::map<std::pair<AssertingVH<const Value>, MemoryKind>,
std::unique_ptr<ScopArrayInfo>>;
using ArrayNameMapTy = StringMap<std::unique_ptr<ScopArrayInfo>>;
using ArrayInfoSetTy = SetVector<ScopArrayInfo *>;
/// A map to remember ScopArrayInfo objects for all base pointers.
///
/// As PHI nodes may have two array info objects associated, we add a flag
/// that distinguishes between the PHI node specific ArrayInfo object
/// and the normal one.
ArrayInfoMapTy ScopArrayInfoMap;
/// A map to remember ScopArrayInfo objects for all names of memory
/// references.
ArrayNameMapTy ScopArrayNameMap;
/// A set to remember ScopArrayInfo objects.
/// @see Scop::ScopArrayInfoMap
ArrayInfoSetTy ScopArrayInfoSet;
/// The assumptions under which this scop was built.
///
/// When constructing a scop sometimes the exact representation of a statement
/// or condition would be very complex, but there is a common case which is a
/// lot simpler, but which is only valid under certain assumptions. The
/// assumed context records the assumptions taken during the construction of
/// this scop and that need to be code generated as a run-time test.
isl::set AssumedContext;
/// The restrictions under which this SCoP was built.
///
/// The invalid context is similar to the assumed context as it contains
/// constraints over the parameters. However, while we need the constraints
/// in the assumed context to be "true" the constraints in the invalid context
/// need to be "false". Otherwise they behave the same.
isl::set InvalidContext;
/// The context under which the SCoP must have defined behavior. Optimizer and
/// code generator can assume that the SCoP will only be executed with
/// parameter values within this context. This might be either because we can
/// prove that other values are impossible or explicitly have undefined
/// behavior, such as due to no-wrap flags. If this becomes too complex, can
/// also be nullptr.
///
/// In contrast to Scop::AssumedContext and Scop::InvalidContext, these do not
/// need to be checked at runtime.
///
/// Scop::Context on the other side is an overapproximation and does not
/// include all requirements, but is always defined. However, there is still
/// no guarantee that there is no undefined behavior in
/// DefinedBehaviorContext.
isl::set DefinedBehaviorContext;
/// The schedule of the SCoP
///
/// The schedule of the SCoP describes the execution order of the statements
/// in the scop by assigning each statement instance a possibly
/// multi-dimensional execution time. The schedule is stored as a tree of
/// schedule nodes.
///
/// The most common nodes in a schedule tree are so-called band nodes. Band
/// nodes map statement instances into a multi dimensional schedule space.
/// This space can be seen as a multi-dimensional clock.
///
/// Example:
///
/// <S,(5,4)> may be mapped to (5,4) by this schedule:
///
/// s0 = i (Year of execution)
/// s1 = j (Day of execution)
///
/// or to (9, 20) by this schedule:
///
/// s0 = i + j (Year of execution)
/// s1 = 20 (Day of execution)
///
/// The order statement instances are executed is defined by the
/// schedule vectors they are mapped to. A statement instance
/// <A, (i, j, ..)> is executed before a statement instance <B, (i', ..)>, if
/// the schedule vector of A is lexicographic smaller than the schedule
/// vector of B.
///
/// Besides band nodes, schedule trees contain additional nodes that specify
/// a textual ordering between two subtrees or filter nodes that filter the
/// set of statement instances that will be scheduled in a subtree. There
/// are also several other nodes. A full description of the different nodes
/// in a schedule tree is given in the isl manual.
isl::schedule Schedule;
/// Is this Scop marked as not to be transformed by an optimization heuristic?
bool HasDisableHeuristicsHint = false;
/// Whether the schedule has been modified after derived from the CFG by
/// ScopBuilder.
bool ScheduleModified = false;
/// The set of minimal/maximal accesses for each alias group.
///
/// When building runtime alias checks we look at all memory instructions and
/// build so called alias groups. Each group contains a set of accesses to
/// different base arrays which might alias with each other. However, between
/// alias groups there is no aliasing possible.
///
/// In a program with int and float pointers annotated with tbaa information
/// we would probably generate two alias groups, one for the int pointers and
/// one for the float pointers.
///
/// During code generation we will create a runtime alias check for each alias
/// group to ensure the SCoP is executed in an alias free environment.
MinMaxVectorPairVectorTy MinMaxAliasGroups;
/// Mapping from invariant loads to the representing invariant load of
/// their equivalence class.
ValueToValueMap InvEquivClassVMap;
/// List of invariant accesses.
InvariantEquivClassesTy InvariantEquivClasses;
/// The smallest array index not yet assigned.
long ArrayIdx = 0;
/// The smallest statement index not yet assigned.
long StmtIdx = 0;
/// A number that uniquely represents a Scop within its function
const int ID;
/// Map of values to the MemoryAccess that writes its definition.
///
/// There must be at most one definition per llvm::Instruction in a SCoP.
DenseMap<Value *, MemoryAccess *> ValueDefAccs;
/// Map of values to the MemoryAccess that reads a PHI.
DenseMap<PHINode *, MemoryAccess *> PHIReadAccs;
/// List of all uses (i.e. read MemoryAccesses) for a MemoryKind::Value
/// scalar.
DenseMap<const ScopArrayInfo *, SmallVector<MemoryAccess *, 4>> ValueUseAccs;
/// List of all incoming values (write MemoryAccess) of a MemoryKind::PHI or
/// MemoryKind::ExitPHI scalar.
DenseMap<const ScopArrayInfo *, SmallVector<MemoryAccess *, 4>>
PHIIncomingAccs;
/// Scop constructor; invoked from ScopBuilder::buildScop.
Scop(Region &R, ScalarEvolution &SE, LoopInfo &LI, DominatorTree &DT,
ScopDetection::DetectionContext &DC, OptimizationRemarkEmitter &ORE,
int ID);
//@}
/// Initialize this ScopBuilder.
void init(AAResults &AA, AssumptionCache &AC, DominatorTree &DT,
LoopInfo &LI);
/// Return the access for the base ptr of @p MA if any.
MemoryAccess *lookupBasePtrAccess(MemoryAccess *MA);
/// Create an id for @p Param and store it in the ParameterIds map.
void createParameterId(const SCEV *Param);
/// Build the Context of the Scop.
void buildContext();
/// Add the bounds of the parameters to the context.
void addParameterBounds();
/// Simplify the assumed and invalid context.
void simplifyContexts();
/// Create a new SCoP statement for @p BB.
///
/// A new statement for @p BB will be created and added to the statement
/// vector
/// and map.
///
/// @param BB The basic block we build the statement for.
/// @param Name The name of the new statement.
/// @param SurroundingLoop The loop the created statement is contained in.
/// @param Instructions The instructions in the statement.
void addScopStmt(BasicBlock *BB, StringRef Name, Loop *SurroundingLoop,
std::vector<Instruction *> Instructions);
/// Create a new SCoP statement for @p R.
///
/// A new statement for @p R will be created and added to the statement vector
/// and map.
///
/// @param R The region we build the statement for.
/// @param Name The name of the new statement.
/// @param SurroundingLoop The loop the created statement is contained
/// in.
/// @param EntryBlockInstructions The (interesting) instructions in the
/// entry block of the region statement.
void addScopStmt(Region *R, StringRef Name, Loop *SurroundingLoop,
std::vector<Instruction *> EntryBlockInstructions);
/// Removes @p Stmt from the StmtMap.
void removeFromStmtMap(ScopStmt &Stmt);
/// Removes all statements where the entry block of the statement does not
/// have a corresponding domain in the domain map (or it is empty).
void removeStmtNotInDomainMap();
/// Collect all memory access relations of a given type.
///
/// @param Predicate A predicate function that returns true if an access is
/// of a given type.
///
/// @returns The set of memory accesses in the scop that match the predicate.
isl::union_map
getAccessesOfType(std::function<bool(MemoryAccess &)> Predicate);
/// @name Helper functions for printing the Scop.
///
//@{
void printContext(raw_ostream &OS) const;
void printArrayInfo(raw_ostream &OS) const;
void printStatements(raw_ostream &OS, bool PrintInstructions) const;
void printAliasAssumptions(raw_ostream &OS) const;
//@}
public:
Scop(const Scop &) = delete;
Scop &operator=(const Scop &) = delete;
~Scop();
/// Increment actual number of aliasing assumptions taken
///
/// @param Step Number of new aliasing assumptions which should be added to
/// the number of already taken assumptions.
static void incrementNumberOfAliasingAssumptions(unsigned Step);
/// Get the count of copy statements added to this Scop.
///
/// @return The count of copy statements added to this Scop.
unsigned getCopyStmtsNum() { return CopyStmtsNum; }
/// Create a new copy statement.
///
/// A new statement will be created and added to the statement vector.
///
/// @param SourceRel The source location.
/// @param TargetRel The target location.
/// @param Domain The original domain under which the copy statement would
/// be executed.
ScopStmt *addScopStmt(isl::map SourceRel, isl::map TargetRel,
isl::set Domain);
/// Add the access function to all MemoryAccess objects of the Scop
/// created in this pass.
void addAccessFunction(MemoryAccess *Access) {
AccessFunctions.emplace_back(Access);
// Register value definitions.
if (Access->isWrite() && Access->isOriginalValueKind()) {
assert(!ValueDefAccs.count(Access->getAccessValue()) &&
"there can be just one definition per value");
ValueDefAccs[Access->getAccessValue()] = Access;
} else if (Access->isRead() && Access->isOriginalPHIKind()) {
PHINode *PHI = cast<PHINode>(Access->getAccessInstruction());
assert(!PHIReadAccs.count(PHI) &&
"there can be just one PHI read per PHINode");
PHIReadAccs[PHI] = Access;
}
}
/// Add metadata for @p Access.
void addAccessData(MemoryAccess *Access);
/// Add new invariant access equivalence class
void
addInvariantEquivClass(const InvariantEquivClassTy &InvariantEquivClass) {
InvariantEquivClasses.emplace_back(InvariantEquivClass);
}
/// Add mapping from invariant loads to the representing invariant load of
/// their equivalence class.
void addInvariantLoadMapping(const Value *LoadInst, Value *ClassRep) {
InvEquivClassVMap[LoadInst] = ClassRep;
}
/// Remove the metadata stored for @p Access.
void removeAccessData(MemoryAccess *Access);
/// Return the scalar evolution.
ScalarEvolution *getSE() const;
/// Return the dominator tree.
DominatorTree *getDT() const { return DT; }
/// Return the LoopInfo used for this Scop.
LoopInfo *getLI() const { return Affinator.getLI(); }
/// Get the count of parameters used in this Scop.
///
/// @return The count of parameters used in this Scop.
size_t getNumParams() const { return Parameters.size(); }
/// Return whether given SCEV is used as the parameter in this Scop.
bool isParam(const SCEV *Param) const { return Parameters.count(Param); }
/// Take a list of parameters and add the new ones to the scop.
void addParams(const ParameterSetTy &NewParameters);
/// Return an iterator range containing the scop parameters.
iterator_range<ParameterSetTy::iterator> parameters() const {
return make_range(Parameters.begin(), Parameters.end());
}
/// Return an iterator range containing invariant accesses.
iterator_range<InvariantEquivClassesTy::iterator> invariantEquivClasses() {
return make_range(InvariantEquivClasses.begin(),
InvariantEquivClasses.end());
}
/// Return an iterator range containing all the MemoryAccess objects of the
/// Scop.
iterator_range<AccFuncVector::iterator> access_functions() {
return make_range(AccessFunctions.begin(), AccessFunctions.end());
}
/// Return whether this scop is empty, i.e. contains no statements that
/// could be executed.
bool isEmpty() const { return Stmts.empty(); }
StringRef getName() {
if (!name)
name = R.getNameStr();
return *name;
}
using array_iterator = ArrayInfoSetTy::iterator;
using const_array_iterator = ArrayInfoSetTy::const_iterator;
using array_range = iterator_range<ArrayInfoSetTy::iterator>;
using const_array_range = iterator_range<ArrayInfoSetTy::const_iterator>;
inline array_iterator array_begin() { return ScopArrayInfoSet.begin(); }
inline array_iterator array_end() { return ScopArrayInfoSet.end(); }
inline const_array_iterator array_begin() const {
return ScopArrayInfoSet.begin();
}
inline const_array_iterator array_end() const {
return ScopArrayInfoSet.end();
}
inline array_range arrays() {
return array_range(array_begin(), array_end());
}
inline const_array_range arrays() const {
return const_array_range(array_begin(), array_end());
}
/// Return the isl_id that represents a certain parameter.
///
/// @param Parameter A SCEV that was recognized as a Parameter.
///
/// @return The corresponding isl_id or NULL otherwise.
isl::id getIdForParam(const SCEV *Parameter) const;
/// Get the maximum region of this static control part.
///
/// @return The maximum region of this static control part.
inline const Region &getRegion() const { return R; }
inline Region &getRegion() { return R; }
/// Return the function this SCoP is in.
Function &getFunction() const { return *R.getEntry()->getParent(); }
/// Check if @p L is contained in the SCoP.
bool contains(const Loop *L) const { return R.contains(L); }
/// Check if @p BB is contained in the SCoP.
bool contains(const BasicBlock *BB) const { return R.contains(BB); }
/// Check if @p I is contained in the SCoP.
bool contains(const Instruction *I) const { return R.contains(I); }
/// Return the unique exit block of the SCoP.
BasicBlock *getExit() const { return R.getExit(); }
/// Return the unique exiting block of the SCoP if any.
BasicBlock *getExitingBlock() const { return R.getExitingBlock(); }
/// Return the unique entry block of the SCoP.
BasicBlock *getEntry() const { return R.getEntry(); }
/// Return the unique entering block of the SCoP if any.
BasicBlock *getEnteringBlock() const { return R.getEnteringBlock(); }
/// Return true if @p BB is the exit block of the SCoP.
bool isExit(BasicBlock *BB) const { return getExit() == BB; }
/// Return a range of all basic blocks in the SCoP.
Region::block_range blocks() const { return R.blocks(); }
/// Return true if and only if @p BB dominates the SCoP.
bool isDominatedBy(const DominatorTree &DT, BasicBlock *BB) const;
/// Get the maximum depth of the loop.
///
/// @return The maximum depth of the loop.
inline unsigned getMaxLoopDepth() const { return MaxLoopDepth; }
/// Return the invariant equivalence class for @p Val if any.
InvariantEquivClassTy *lookupInvariantEquivClass(Value *Val);
/// Return the set of invariant accesses.
InvariantEquivClassesTy &getInvariantAccesses() {
return InvariantEquivClasses;
}
/// Check if the scop has any invariant access.
bool hasInvariantAccesses() { return !InvariantEquivClasses.empty(); }
/// Mark the SCoP as optimized by the scheduler.
void markAsOptimized() { IsOptimized = true; }
/// Check if the SCoP has been optimized by the scheduler.
bool isOptimized() const { return IsOptimized; }
/// Mark the SCoP to be skipped by ScopPass passes.
void markAsToBeSkipped() { SkipScop = true; }
/// Check if the SCoP is to be skipped by ScopPass passes.
bool isToBeSkipped() const { return SkipScop; }
/// Return the ID of the Scop
int getID() const { return ID; }
/// Get the name of the entry and exit blocks of this Scop.
///
/// These along with the function name can uniquely identify a Scop.
///
/// @return std::pair whose first element is the entry name & second element
/// is the exit name.
std::pair<std::string, std::string> getEntryExitStr() const;
/// Get the name of this Scop.
std::string getNameStr() const;
/// Get the constraint on parameter of this Scop.
///
/// @return The constraint on parameter of this Scop.
isl::set getContext() const;
/// Return the context where execution behavior is defined. Might return
/// nullptr.
isl::set getDefinedBehaviorContext() const { return DefinedBehaviorContext; }
/// Return the define behavior context, or if not available, its approximation
/// from all other contexts.
isl::set getBestKnownDefinedBehaviorContext() const {
if (!DefinedBehaviorContext.is_null())
return DefinedBehaviorContext;
return Context.intersect_params(AssumedContext).subtract(InvalidContext);
}
/// Return space of isl context parameters.
///
/// Returns the set of context parameters that are currently constrained. In
/// case the full set of parameters is needed, see @getFullParamSpace.
isl::space getParamSpace() const;
/// Return the full space of parameters.
///
/// getParamSpace will only return the parameters of the context that are
/// actually constrained, whereas getFullParamSpace will return all
// parameters. This is useful in cases, where we need to ensure all
// parameters are available, as certain isl functions will abort if this is
// not the case.
isl::space getFullParamSpace() const;
/// Get the assumed context for this Scop.
///
/// @return The assumed context of this Scop.
isl::set getAssumedContext() const;
/// Return true if the optimized SCoP can be executed.
///
/// In addition to the runtime check context this will also utilize the domain
/// constraints to decide it the optimized version can actually be executed.
///
/// @returns True if the optimized SCoP can be executed.
bool hasFeasibleRuntimeContext() const;
/// Check if the assumption in @p Set is trivial or not.
///
/// @param Set The relations between parameters that are assumed to hold.
/// @param Sign Enum to indicate if the assumptions in @p Set are positive
/// (needed/assumptions) or negative (invalid/restrictions).
///
/// @returns True if the assumption @p Set is not trivial.
bool isEffectiveAssumption(isl::set Set, AssumptionSign Sign);
/// Track and report an assumption.
///
/// Use 'clang -Rpass-analysis=polly-scops' or 'opt
/// -pass-remarks-analysis=polly-scops' to output the assumptions.
///
/// @param Kind The assumption kind describing the underlying cause.
/// @param Set The relations between parameters that are assumed to hold.
/// @param Loc The location in the source that caused this assumption.
/// @param Sign Enum to indicate if the assumptions in @p Set are positive
/// (needed/assumptions) or negative (invalid/restrictions).
/// @param BB The block in which this assumption was taken. Used to
/// calculate hotness when emitting remark.
///
/// @returns True if the assumption is not trivial.
bool trackAssumption(AssumptionKind Kind, isl::set Set, DebugLoc Loc,
AssumptionSign Sign, BasicBlock *BB);
/// Add the conditions from @p Set (or subtract them if @p Sign is
/// AS_RESTRICTION) to the defined behaviour context.
void intersectDefinedBehavior(isl::set Set, AssumptionSign Sign);
/// Add assumptions to assumed context.
///
/// The assumptions added will be assumed to hold during the execution of the
/// scop. However, as they are generally not statically provable, at code
/// generation time run-time checks will be generated that ensure the
/// assumptions hold.
///
/// WARNING: We currently exploit in simplifyAssumedContext the knowledge
/// that assumptions do not change the set of statement instances
/// executed.
///
/// @param Kind The assumption kind describing the underlying cause.
/// @param Set The relations between parameters that are assumed to hold.
/// @param Loc The location in the source that caused this assumption.
/// @param Sign Enum to indicate if the assumptions in @p Set are positive
/// (needed/assumptions) or negative (invalid/restrictions).
/// @param BB The block in which this assumption was taken. Used to
/// calculate hotness when emitting remark.
/// @param RTC Does the assumption require a runtime check?
void addAssumption(AssumptionKind Kind, isl::set Set, DebugLoc Loc,
AssumptionSign Sign, BasicBlock *BB, bool RTC = true);
/// Mark the scop as invalid.
///
/// This method adds an assumption to the scop that is always invalid. As a
/// result, the scop will not be optimized later on. This function is commonly
/// called when a condition makes it impossible (or too compile time
/// expensive) to process this scop any further.
///
/// @param Kind The assumption kind describing the underlying cause.
/// @param Loc The location in the source that triggered .
/// @param BB The BasicBlock where it was triggered.
void invalidate(AssumptionKind Kind, DebugLoc Loc, BasicBlock *BB = nullptr);
/// Get the invalid context for this Scop.
///
/// @return The invalid context of this Scop.
isl::set getInvalidContext() const;
/// Return true if and only if the InvalidContext is trivial (=empty).
bool hasTrivialInvalidContext() const { return InvalidContext.is_empty(); }
/// Return all alias groups for this SCoP.
const MinMaxVectorPairVectorTy &getAliasGroups() const {
return MinMaxAliasGroups;
}
void addAliasGroup(MinMaxVectorTy &MinMaxAccessesReadWrite,
MinMaxVectorTy &MinMaxAccessesReadOnly) {
MinMaxAliasGroups.emplace_back();
MinMaxAliasGroups.back().first = MinMaxAccessesReadWrite;
MinMaxAliasGroups.back().second = MinMaxAccessesReadOnly;
}
/// Remove statements from the list of scop statements.
///
/// @param ShouldDelete A function that returns true if the statement passed
/// to it should be deleted.
/// @param AfterHoisting If true, also remove from data access lists.
/// These lists are filled during
/// ScopBuilder::buildAccessRelations. Therefore, if this
/// method is called before buildAccessRelations, false
/// must be passed.
void removeStmts(function_ref<bool(ScopStmt &)> ShouldDelete,
bool AfterHoisting = true);
/// Get an isl string representing the context.
std::string getContextStr() const;
/// Get an isl string representing the assumed context.
std::string getAssumedContextStr() const;
/// Get an isl string representing the invalid context.
std::string getInvalidContextStr() const;
/// Return the list of ScopStmts that represent the given @p BB.
ArrayRef<ScopStmt *> getStmtListFor(BasicBlock *BB) const;
/// Get the statement to put a PHI WRITE into.
///
/// @param U The operand of a PHINode.
ScopStmt *getIncomingStmtFor(const Use &U) const;
/// Return the last statement representing @p BB.
///
/// Of the sequence of statements that represent a @p BB, this is the last one
/// to be executed. It is typically used to determine which instruction to add
/// a MemoryKind::PHI WRITE to. For this purpose, it is not strictly required
/// to be executed last, only that the incoming value is available in it.
ScopStmt *getLastStmtFor(BasicBlock *BB) const;
/// Return the ScopStmts that represents the Region @p R, or nullptr if
/// it is not represented by any statement in this Scop.
ArrayRef<ScopStmt *> getStmtListFor(Region *R) const;
/// Return the ScopStmts that represents @p RN; can return nullptr if
/// the RegionNode is not within the SCoP or has been removed due to
/// simplifications.
ArrayRef<ScopStmt *> getStmtListFor(RegionNode *RN) const;
/// Return the ScopStmt an instruction belongs to, or nullptr if it
/// does not belong to any statement in this Scop.
ScopStmt *getStmtFor(Instruction *Inst) const {
return InstStmtMap.lookup(Inst);
}
/// Return the number of statements in the SCoP.
size_t getSize() const { return Stmts.size(); }
/// @name Statements Iterators
///
/// These iterators iterate over all statements of this Scop.
//@{
using iterator = StmtSet::iterator;
using const_iterator = StmtSet::const_iterator;
iterator begin() { return Stmts.begin(); }
iterator end() { return Stmts.end(); }
const_iterator begin() const { return Stmts.begin(); }
const_iterator end() const { return Stmts.end(); }
using reverse_iterator = StmtSet::reverse_iterator;
using const_reverse_iterator = StmtSet::const_reverse_iterator;
reverse_iterator rbegin() { return Stmts.rbegin(); }
reverse_iterator rend() { return Stmts.rend(); }
const_reverse_iterator rbegin() const { return Stmts.rbegin(); }
const_reverse_iterator rend() const { return Stmts.rend(); }
//@}
/// Return the set of required invariant loads.
const InvariantLoadsSetTy &getRequiredInvariantLoads() const {
return DC.RequiredILS;
}
/// Add @p LI to the set of required invariant loads.
void addRequiredInvariantLoad(LoadInst *LI) { DC.RequiredILS.insert(LI); }
/// Return the set of boxed (thus overapproximated) loops.
const BoxedLoopsSetTy &getBoxedLoops() const { return DC.BoxedLoopsSet; }
/// Return true if and only if @p R is a non-affine subregion.
bool isNonAffineSubRegion(const Region *R) {
return DC.NonAffineSubRegionSet.count(R);
}
const MapInsnToMemAcc &getInsnToMemAccMap() const { return DC.InsnToMemAcc; }
/// Return the (possibly new) ScopArrayInfo object for @p Access.
///
/// @param ElementType The type of the elements stored in this array.
/// @param Kind The kind of the array info object.
/// @param BaseName The optional name of this memory reference.
ScopArrayInfo *getOrCreateScopArrayInfo(Value *BasePtr, Type *ElementType,
ArrayRef<const SCEV *> Sizes,
MemoryKind Kind,
const char *BaseName = nullptr);
/// Create an array and return the corresponding ScopArrayInfo object.
///
/// @param ElementType The type of the elements stored in this array.
/// @param BaseName The name of this memory reference.
/// @param Sizes The sizes of dimensions.
ScopArrayInfo *createScopArrayInfo(Type *ElementType,
const std::string &BaseName,
const std::vector<unsigned> &Sizes);
/// Return the cached ScopArrayInfo object for @p BasePtr.
///
/// @param BasePtr The base pointer the object has been stored for.
/// @param Kind The kind of array info object.
///
/// @returns The ScopArrayInfo pointer or NULL if no such pointer is
/// available.
ScopArrayInfo *getScopArrayInfoOrNull(Value *BasePtr, MemoryKind Kind);
/// Return the cached ScopArrayInfo object for @p BasePtr.
///
/// @param BasePtr The base pointer the object has been stored for.
/// @param Kind The kind of array info object.
///
/// @returns The ScopArrayInfo pointer (may assert if no such pointer is
/// available).
ScopArrayInfo *getScopArrayInfo(Value *BasePtr, MemoryKind Kind);
/// Invalidate ScopArrayInfo object for base address.
///
/// @param BasePtr The base pointer of the ScopArrayInfo object to invalidate.
/// @param Kind The Kind of the ScopArrayInfo object.
void invalidateScopArrayInfo(Value *BasePtr, MemoryKind Kind) {
auto It = ScopArrayInfoMap.find(std::make_pair(BasePtr, Kind));
if (It == ScopArrayInfoMap.end())
return;
ScopArrayInfoSet.remove(It->second.get());
ScopArrayInfoMap.erase(It);
}
/// Set new isl context.
void setContext(isl::set NewContext);
/// Update maximal loop depth. If @p Depth is smaller than current value,
/// then maximal loop depth is not updated.
void updateMaxLoopDepth(unsigned Depth) {
MaxLoopDepth = std::max(MaxLoopDepth, Depth);
}
/// Align the parameters in the statement to the scop context
void realignParams();
/// Return true if this SCoP can be profitably optimized.
///
/// @param ScalarsAreUnprofitable Never consider statements with scalar writes
/// as profitably optimizable.
///
/// @return Whether this SCoP can be profitably optimized.
bool isProfitable(bool ScalarsAreUnprofitable) const;
/// Return true if the SCoP contained at least one error block.
bool hasErrorBlock() const { return HasErrorBlock; }
/// Notify SCoP that it contains an error block
void notifyErrorBlock() { HasErrorBlock = true; }
/// Return true if the underlying region has a single exiting block.
bool hasSingleExitEdge() const { return HasSingleExitEdge; }
/// Print the static control part.
///
/// @param OS The output stream the static control part is printed to.
/// @param PrintInstructions Whether to print the statement's instructions as
/// well.
void print(raw_ostream &OS, bool PrintInstructions) const;
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
/// Print the ScopStmt to stderr.
void dump() const;
#endif
/// Get the isl context of this static control part.
///
/// @return The isl context of this static control part.
isl::ctx getIslCtx() const;
/// Directly return the shared_ptr of the context.
const std::shared_ptr<isl_ctx> &getSharedIslCtx() const { return IslCtx; }
/// Compute the isl representation for the SCEV @p E
///
/// @param E The SCEV that should be translated.
/// @param BB An (optional) basic block in which the isl_pw_aff is computed.
/// SCEVs known to not reference any loops in the SCoP can be
/// passed without a @p BB.
/// @param NonNegative Flag to indicate the @p E has to be non-negative.
///
/// Note that this function will always return a valid isl_pw_aff. However, if
/// the translation of @p E was deemed to complex the SCoP is invalidated and
/// a dummy value of appropriate dimension is returned. This allows to bail
/// for complex cases without "error handling code" needed on the users side.
PWACtx getPwAff(const SCEV *E, BasicBlock *BB = nullptr,
bool NonNegative = false,
RecordedAssumptionsTy *RecordedAssumptions = nullptr);
/// Compute the isl representation for the SCEV @p E
///
/// This function is like @see Scop::getPwAff() but strips away the invalid
/// domain part associated with the piecewise affine function.
isl::pw_aff
getPwAffOnly(const SCEV *E, BasicBlock *BB = nullptr,
RecordedAssumptionsTy *RecordedAssumptions = nullptr);
/// Check if an <nsw> AddRec for the loop L is cached.
bool hasNSWAddRecForLoop(Loop *L) { return Affinator.hasNSWAddRecForLoop(L); }
/// Return the domain of @p Stmt.
///
/// @param Stmt The statement for which the conditions should be returned.
isl::set getDomainConditions(const ScopStmt *Stmt) const;
/// Return the domain of @p BB.
///
/// @param BB The block for which the conditions should be returned.
isl::set getDomainConditions(BasicBlock *BB) const;
/// Return the domain of @p BB. If it does not exist, create an empty one.
isl::set &getOrInitEmptyDomain(BasicBlock *BB) { return DomainMap[BB]; }
/// Check if domain is determined for @p BB.
bool isDomainDefined(BasicBlock *BB) const { return DomainMap.count(BB) > 0; }
/// Set domain for @p BB.
void setDomain(BasicBlock *BB, isl::set &Domain) { DomainMap[BB] = Domain; }
/// Get a union set containing the iteration domains of all statements.
isl::union_set getDomains() const;
/// Get a union map of all may-writes performed in the SCoP.
isl::union_map getMayWrites();
/// Get a union map of all must-writes performed in the SCoP.
isl::union_map getMustWrites();
/// Get a union map of all writes performed in the SCoP.
isl::union_map getWrites();
/// Get a union map of all reads performed in the SCoP.
isl::union_map getReads();
/// Get a union map of all memory accesses performed in the SCoP.
isl::union_map getAccesses();
/// Get a union map of all memory accesses performed in the SCoP.
///
/// @param Array The array to which the accesses should belong.
isl::union_map getAccesses(ScopArrayInfo *Array);
/// Get the schedule of all the statements in the SCoP.
///
/// @return The schedule of all the statements in the SCoP, if the schedule of
/// the Scop does not contain extension nodes, and nullptr, otherwise.
isl::union_map getSchedule() const;
/// Get a schedule tree describing the schedule of all statements.
isl::schedule getScheduleTree() const;
/// Update the current schedule
///
/// NewSchedule The new schedule (given as a flat union-map).
void setSchedule(isl::union_map NewSchedule);
/// Update the current schedule
///
/// NewSchedule The new schedule (given as schedule tree).
void setScheduleTree(isl::schedule NewSchedule);
/// Whether the schedule is the original schedule as derived from the CFG by
/// ScopBuilder.
bool isOriginalSchedule() const { return !ScheduleModified; }
/// Intersects the domains of all statements in the SCoP.
///
/// @return true if a change was made
bool restrictDomains(isl::union_set Domain);
/// Get the depth of a loop relative to the outermost loop in the Scop.
///
/// This will return
/// 0 if @p L is an outermost loop in the SCoP
/// >0 for other loops in the SCoP
/// -1 if @p L is nullptr or there is no outermost loop in the SCoP
int getRelativeLoopDepth(const Loop *L) const;
/// Find the ScopArrayInfo associated with an isl Id
/// that has name @p Name.
ScopArrayInfo *getArrayInfoByName(const std::string BaseName);
/// Simplify the SCoP representation.
///
/// @param AfterHoisting Whether it is called after invariant load hoisting.
/// When true, also removes statements without
/// side-effects.
void simplifySCoP(bool AfterHoisting);
/// Get the next free array index.
///
/// This function returns a unique index which can be used to identify an
/// array.
long getNextArrayIdx() { return ArrayIdx++; }
/// Get the next free statement index.
///
/// This function returns a unique index which can be used to identify a
/// statement.
long getNextStmtIdx() { return StmtIdx++; }
/// Get the representing SCEV for @p S if applicable, otherwise @p S.
///
/// Invariant loads of the same location are put in an equivalence class and
/// only one of them is chosen as a representing element that will be
/// modeled as a parameter. The others have to be normalized, i.e.,
/// replaced by the representing element of their equivalence class, in order
/// to get the correct parameter value, e.g., in the SCEVAffinator.
///
/// @param S The SCEV to normalize.
///
/// @return The representing SCEV for invariant loads or @p S if none.
const SCEV *getRepresentingInvariantLoadSCEV(const SCEV *S) const;
/// Return the MemoryAccess that writes an llvm::Value, represented by a
/// ScopArrayInfo.
///
/// There can be at most one such MemoryAccess per llvm::Value in the SCoP.
/// Zero is possible for read-only values.
MemoryAccess *getValueDef(const ScopArrayInfo *SAI) const;
/// Return all MemoryAccesses that us an llvm::Value, represented by a
/// ScopArrayInfo.
ArrayRef<MemoryAccess *> getValueUses(const ScopArrayInfo *SAI) const;
/// Return the MemoryAccess that represents an llvm::PHINode.
///
/// ExitPHIs's PHINode is not within the SCoPs. This function returns nullptr
/// for them.
MemoryAccess *getPHIRead(const ScopArrayInfo *SAI) const;
/// Return all MemoryAccesses for all incoming statements of a PHINode,
/// represented by a ScopArrayInfo.
ArrayRef<MemoryAccess *> getPHIIncomings(const ScopArrayInfo *SAI) const;
/// Return whether @p Inst has a use outside of this SCoP.
bool isEscaping(Instruction *Inst);
struct ScopStatistics {
int NumAffineLoops = 0;
int NumBoxedLoops = 0;
int NumValueWrites = 0;
int NumValueWritesInLoops = 0;
int NumPHIWrites = 0;
int NumPHIWritesInLoops = 0;
int NumSingletonWrites = 0;
int NumSingletonWritesInLoops = 0;
};
/// Collect statistic about this SCoP.
///
/// These are most commonly used for LLVM's static counters (Statistic.h) in
/// various places. If statistics are disabled, only zeros are returned to
/// avoid the overhead.
ScopStatistics getStatistics() const;
/// Is this Scop marked as not to be transformed by an optimization heuristic?
/// In this case, only user-directed transformations are allowed.
bool hasDisableHeuristicsHint() const { return HasDisableHeuristicsHint; }
/// Mark this Scop to not apply an optimization heuristic.
void markDisableHeuristics() { HasDisableHeuristicsHint = true; }
};
/// Print Scop scop to raw_ostream OS.
raw_ostream &operator<<(raw_ostream &OS, const Scop &scop);
/// The legacy pass manager's analysis pass to compute scop information
/// for a region.
class ScopInfoRegionPass : public RegionPass {
/// The Scop pointer which is used to construct a Scop.
std::unique_ptr<Scop> S;
public:
static char ID; // Pass identification, replacement for typeid
ScopInfoRegionPass() : RegionPass(ID) {}
~ScopInfoRegionPass() override = default;
/// Build Scop object, the Polly IR of static control
/// part for the current SESE-Region.
///
/// @return If the current region is a valid for a static control part,
/// return the Polly IR representing this static control part,
/// return null otherwise.
Scop *getScop() { return S.get(); }
const Scop *getScop() const { return S.get(); }
/// Calculate the polyhedral scop information for a given Region.
bool runOnRegion(Region *R, RGPassManager &RGM) override;
void releaseMemory() override { S.reset(); }
void print(raw_ostream &O, const Module *M = nullptr) const override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
};
class ScopInfo {
public:
using RegionToScopMapTy = MapVector<Region *, std::unique_ptr<Scop>>;
using reverse_iterator = RegionToScopMapTy::reverse_iterator;
using const_reverse_iterator = RegionToScopMapTy::const_reverse_iterator;
using iterator = RegionToScopMapTy::iterator;
using const_iterator = RegionToScopMapTy::const_iterator;
private:
/// A map of Region to its Scop object containing
/// Polly IR of static control part.
RegionToScopMapTy RegionToScopMap;
const DataLayout &DL;
ScopDetection &SD;
ScalarEvolution &SE;
LoopInfo &LI;
AAResults &AA;
DominatorTree &DT;
AssumptionCache &AC;
OptimizationRemarkEmitter &ORE;
public:
ScopInfo(const DataLayout &DL, ScopDetection &SD, ScalarEvolution &SE,
LoopInfo &LI, AAResults &AA, DominatorTree &DT, AssumptionCache &AC,
OptimizationRemarkEmitter &ORE);
/// Get the Scop object for the given Region.
///
/// @return If the given region is the maximal region within a scop, return
/// the scop object. If the given region is a subregion, return a
/// nullptr. Top level region containing the entry block of a function
/// is not considered in the scop creation.
Scop *getScop(Region *R) const {
auto MapIt = RegionToScopMap.find(R);
if (MapIt != RegionToScopMap.end())
return MapIt->second.get();
return nullptr;
}
/// Recompute the Scop-Information for a function.
///
/// This invalidates any iterators.
void recompute();
/// Handle invalidation explicitly
bool invalidate(Function &F, const PreservedAnalyses &PA,
FunctionAnalysisManager::Invalidator &Inv);
iterator begin() { return RegionToScopMap.begin(); }
iterator end() { return RegionToScopMap.end(); }
const_iterator begin() const { return RegionToScopMap.begin(); }
const_iterator end() const { return RegionToScopMap.end(); }
reverse_iterator rbegin() { return RegionToScopMap.rbegin(); }
reverse_iterator rend() { return RegionToScopMap.rend(); }
const_reverse_iterator rbegin() const { return RegionToScopMap.rbegin(); }
const_reverse_iterator rend() const { return RegionToScopMap.rend(); }
bool empty() const { return RegionToScopMap.empty(); }
};
struct ScopInfoAnalysis : public AnalysisInfoMixin<ScopInfoAnalysis> {
static AnalysisKey Key;
using Result = ScopInfo;
Result run(Function &, FunctionAnalysisManager &);
};
struct ScopInfoPrinterPass : public PassInfoMixin<ScopInfoPrinterPass> {
ScopInfoPrinterPass(raw_ostream &OS) : Stream(OS) {}
PreservedAnalyses run(Function &, FunctionAnalysisManager &);
raw_ostream &Stream;
};
//===----------------------------------------------------------------------===//
/// The legacy pass manager's analysis pass to compute scop information
/// for the whole function.
///
/// This pass will maintain a map of the maximal region within a scop to its
/// scop object for all the feasible scops present in a function.
/// This pass is an alternative to the ScopInfoRegionPass in order to avoid a
/// region pass manager.
class ScopInfoWrapperPass : public FunctionPass {
std::unique_ptr<ScopInfo> Result;
public:
ScopInfoWrapperPass() : FunctionPass(ID) {}
~ScopInfoWrapperPass() override = default;
static char ID; // Pass identification, replacement for typeid
ScopInfo *getSI() { return Result.get(); }
const ScopInfo *getSI() const { return Result.get(); }
/// Calculate all the polyhedral scops for a given function.
bool runOnFunction(Function &F) override;
void releaseMemory() override { Result.reset(); }
void print(raw_ostream &O, const Module *M = nullptr) const override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
};
} // end namespace polly
#endif // POLLY_SCOPINFO_H