LLVM  7.0.0svn
Classes | Public Types | Public Member Functions | Static Public Member Functions | List of all members
llvm::RecurrenceDescriptor Class Reference

The RecurrenceDescriptor is used to identify recurrences variables in a loop. More...

#include "llvm/Transforms/Utils/LoopUtils.h"

Classes

class  InstDesc
 This POD struct holds information about a potential recurrence operation. More...
 

Public Types

enum  RecurrenceKind {
  RK_NoRecurrence, RK_IntegerAdd, RK_IntegerMult, RK_IntegerOr,
  RK_IntegerAnd, RK_IntegerXor, RK_IntegerMinMax, RK_FloatAdd,
  RK_FloatMult, RK_FloatMinMax
}
 This enum represents the kinds of recurrences that we support. More...
 
enum  MinMaxRecurrenceKind {
  MRK_Invalid, MRK_UIntMin, MRK_UIntMax, MRK_SIntMin,
  MRK_SIntMax, MRK_FloatMin, MRK_FloatMax
}
 

Public Member Functions

 RecurrenceDescriptor ()=default
 
 RecurrenceDescriptor (Value *Start, Instruction *Exit, RecurrenceKind K, MinMaxRecurrenceKind MK, Instruction *UAI, Type *RT, bool Signed, SmallPtrSetImpl< Instruction *> &CI)
 
RecurrenceKind getRecurrenceKind ()
 
MinMaxRecurrenceKind getMinMaxRecurrenceKind ()
 
TrackingVH< ValuegetRecurrenceStartValue ()
 
InstructiongetLoopExitInstr ()
 
bool hasUnsafeAlgebra ()
 Returns true if the recurrence has unsafe algebra which requires a relaxed floating-point model. More...
 
InstructiongetUnsafeAlgebraInst ()
 Returns first unsafe algebra instruction in the PHI node's use-chain. More...
 
TypegetRecurrenceType ()
 Returns the type of the recurrence. More...
 
SmallPtrSet< Instruction *, 8 > & getCastInsts ()
 Returns a reference to the instructions used for type-promoting the recurrence. More...
 
bool isSigned ()
 Returns true if all source operands of the recurrence are SExtInsts. More...
 

Static Public Member Functions

static InstDesc isRecurrenceInstr (Instruction *I, RecurrenceKind Kind, InstDesc &Prev, bool HasFunNoNaNAttr)
 Returns a struct describing if the instruction 'I' can be a recurrence variable of type 'Kind'. More...
 
static bool hasMultipleUsesOf (Instruction *I, SmallPtrSetImpl< Instruction *> &Insts)
 Returns true if instruction I has multiple uses in Insts. More...
 
static bool areAllUsesIn (Instruction *I, SmallPtrSetImpl< Instruction *> &Set)
 Returns true if all uses of the instruction I is within the Set. More...
 
static InstDesc isMinMaxSelectCmpPattern (Instruction *I, InstDesc &Prev)
 Returns a struct describing if the instruction if the instruction is a Select(ICmp(X, Y), X, Y) instruction pattern corresponding to a min(X, Y) or max(X, Y). More...
 
static ConstantgetRecurrenceIdentity (RecurrenceKind K, Type *Tp)
 Returns identity corresponding to the RecurrenceKind. More...
 
static unsigned getRecurrenceBinOp (RecurrenceKind Kind)
 Returns the opcode of binary operation corresponding to the RecurrenceKind. More...
 
static ValuecreateMinMaxOp (IRBuilder<> &Builder, MinMaxRecurrenceKind RK, Value *Left, Value *Right)
 Returns a Min/Max operation corresponding to MinMaxRecurrenceKind. More...
 
static bool AddReductionVar (PHINode *Phi, RecurrenceKind Kind, Loop *TheLoop, bool HasFunNoNaNAttr, RecurrenceDescriptor &RedDes, DemandedBits *DB=nullptr, AssumptionCache *AC=nullptr, DominatorTree *DT=nullptr)
 Returns true if Phi is a reduction of type Kind and adds it to the RecurrenceDescriptor. More...
 
static bool isReductionPHI (PHINode *Phi, Loop *TheLoop, RecurrenceDescriptor &RedDes, DemandedBits *DB=nullptr, AssumptionCache *AC=nullptr, DominatorTree *DT=nullptr)
 Returns true if Phi is a reduction in TheLoop. More...
 
static bool isFirstOrderRecurrence (PHINode *Phi, Loop *TheLoop, DenseMap< Instruction *, Instruction *> &SinkAfter, DominatorTree *DT)
 Returns true if Phi is a first-order recurrence. More...
 
static bool isIntegerRecurrenceKind (RecurrenceKind Kind)
 Returns true if the recurrence kind is an integer kind. More...
 
static bool isFloatingPointRecurrenceKind (RecurrenceKind Kind)
 Returns true if the recurrence kind is a floating point kind. More...
 
static bool isArithmeticRecurrenceKind (RecurrenceKind Kind)
 Returns true if the recurrence kind is an arithmetic kind. More...
 

Detailed Description

The RecurrenceDescriptor is used to identify recurrences variables in a loop.

Reduction is a special case of recurrence that has uses of the recurrence variable outside the loop. The method isReductionPHI identifies reductions that are basic recurrences.

Basic recurrences are defined as the summation, product, OR, AND, XOR, min, or max of a set of terms. For example: for(i=0; i<n; i++) { total += array[i]; } is a summation of array elements. Basic recurrences are a special case of chains of recurrences (CR). See ScalarEvolution for CR references. This struct holds information about recurrence variables.

Definition at line 74 of file LoopUtils.h.

Member Enumeration Documentation

◆ MinMaxRecurrenceKind

Enumerator
MRK_Invalid 
MRK_UIntMin 
MRK_UIntMax 
MRK_SIntMin 
MRK_SIntMax 
MRK_FloatMin 
MRK_FloatMax 

Definition at line 91 of file LoopUtils.h.

◆ RecurrenceKind

This enum represents the kinds of recurrences that we support.

Enumerator
RK_NoRecurrence 

Not a recurrence.

RK_IntegerAdd 

Sum of integers.

RK_IntegerMult 

Product of integers.

RK_IntegerOr 

Bitwise or logical OR of numbers.

RK_IntegerAnd 

Bitwise or logical AND of numbers.

RK_IntegerXor 

Bitwise or logical XOR of numbers.

RK_IntegerMinMax 

Min/max implemented in terms of select(cmp()).

RK_FloatAdd 

Sum of floats.

RK_FloatMult 

Product of floats.

RK_FloatMinMax 

Min/max implemented in terms of select(cmp()).

Definition at line 77 of file LoopUtils.h.

Constructor & Destructor Documentation

◆ RecurrenceDescriptor() [1/2]

llvm::RecurrenceDescriptor::RecurrenceDescriptor ( )
default

◆ RecurrenceDescriptor() [2/2]

llvm::RecurrenceDescriptor::RecurrenceDescriptor ( Value Start,
Instruction Exit,
RecurrenceKind  K,
MinMaxRecurrenceKind  MK,
Instruction UAI,
Type RT,
bool  Signed,
SmallPtrSetImpl< Instruction *> &  CI 
)
inline

Member Function Documentation

◆ AddReductionVar()

bool RecurrenceDescriptor::AddReductionVar ( PHINode Phi,
RecurrenceKind  Kind,
Loop TheLoop,
bool  HasFunNoNaNAttr,
RecurrenceDescriptor RedDes,
DemandedBits DB = nullptr,
AssumptionCache AC = nullptr,
DominatorTree DT = nullptr 
)
static

◆ areAllUsesIn()

bool RecurrenceDescriptor::areAllUsesIn ( Instruction I,
SmallPtrSetImpl< Instruction *> &  Set 
)
static

Returns true if all uses of the instruction I is within the Set.

Definition at line 42 of file LoopUtils.cpp.

References llvm::SmallPtrSetImpl< PtrType >::count(), E, llvm::User::op_begin(), and llvm::User::op_end().

◆ createMinMaxOp()

Value * RecurrenceDescriptor::createMinMaxOp ( IRBuilder<> &  Builder,
MinMaxRecurrenceKind  RK,
Value Left,
Value Right 
)
static

◆ getCastInsts()

SmallPtrSet<Instruction *, 8>& llvm::RecurrenceDescriptor::getCastInsts ( )
inline

Returns a reference to the instructions used for type-promoting the recurrence.

Definition at line 238 of file LoopUtils.h.

Referenced by llvm::LoopVectorizationCostModel::collectValuesToIgnore().

◆ getLoopExitInstr()

Instruction* llvm::RecurrenceDescriptor::getLoopExitInstr ( )
inline

Definition at line 214 of file LoopUtils.h.

Referenced by hasOutsideLoopUser().

◆ getMinMaxRecurrenceKind()

MinMaxRecurrenceKind llvm::RecurrenceDescriptor::getMinMaxRecurrenceKind ( )
inline

Definition at line 210 of file LoopUtils.h.

Referenced by llvm::createTargetReduction().

◆ getRecurrenceBinOp()

unsigned RecurrenceDescriptor::getRecurrenceBinOp ( RecurrenceKind  Kind)
static

Returns the opcode of binary operation corresponding to the RecurrenceKind.

This function translates the recurrence kind to an LLVM binary operator.

Definition at line 683 of file LoopUtils.cpp.

References llvm::MCID::Add, and llvm_unreachable.

Referenced by llvm::InnerLoopVectorizer::fixReduction().

◆ getRecurrenceIdentity()

Constant * RecurrenceDescriptor::getRecurrenceIdentity ( RecurrenceKind  K,
Type Tp 
)
static

Returns identity corresponding to the RecurrenceKind.

This function returns the identity element (or neutral element) for the operation K.

Definition at line 657 of file LoopUtils.cpp.

References llvm::ConstantInt::get(), llvm::ConstantFP::get(), and llvm_unreachable.

Referenced by llvm::InnerLoopVectorizer::fixReduction().

◆ getRecurrenceKind()

RecurrenceKind llvm::RecurrenceDescriptor::getRecurrenceKind ( )
inline

Definition at line 208 of file LoopUtils.h.

References Kind.

Referenced by llvm::createTargetReduction(), and llvm::InnerLoopVectorizer::fixReduction().

◆ getRecurrenceStartValue()

TrackingVH<Value> llvm::RecurrenceDescriptor::getRecurrenceStartValue ( )
inline

Definition at line 212 of file LoopUtils.h.

◆ getRecurrenceType()

Type* llvm::RecurrenceDescriptor::getRecurrenceType ( )
inline

Returns the type of the recurrence.

This type can be narrower than the actual type of the Phi if the recurrence has been type-promoted.

Definition at line 234 of file LoopUtils.h.

Referenced by llvm::LoopVectorizationCostModel::getSmallestAndWidestTypes().

◆ getUnsafeAlgebraInst()

Instruction* llvm::RecurrenceDescriptor::getUnsafeAlgebraInst ( )
inline

Returns first unsafe algebra instruction in the PHI node's use-chain.

Definition at line 221 of file LoopUtils.h.

Referenced by hasOutsideLoopUser().

◆ hasMultipleUsesOf()

bool RecurrenceDescriptor::hasMultipleUsesOf ( Instruction I,
SmallPtrSetImpl< Instruction *> &  Insts 
)
static

Returns true if instruction I has multiple uses in Insts.

Definition at line 531 of file LoopUtils.cpp.

References llvm::SmallPtrSetImpl< PtrType >::count(), E, llvm::User::op_begin(), and llvm::User::op_end().

◆ hasUnsafeAlgebra()

bool llvm::RecurrenceDescriptor::hasUnsafeAlgebra ( )
inline

Returns true if the recurrence has unsafe algebra which requires a relaxed floating-point model.

Definition at line 218 of file LoopUtils.h.

Referenced by hasOutsideLoopUser().

◆ isArithmeticRecurrenceKind()

bool RecurrenceDescriptor::isArithmeticRecurrenceKind ( RecurrenceKind  Kind)
static

Returns true if the recurrence kind is an arithmetic kind.

Definition at line 69 of file LoopUtils.cpp.

◆ isFirstOrderRecurrence()

bool RecurrenceDescriptor::isFirstOrderRecurrence ( PHINode Phi,
Loop TheLoop,
DenseMap< Instruction *, Instruction *> &  SinkAfter,
DominatorTree DT 
)
static

Returns true if Phi is a first-order recurrence.

A first-order recurrence is a non-reduction recurrence relation in which the value of the recurrence in the current loop iteration equals a value defined in the previous iteration. SinkAfter includes pairs of instructions where the first will be rescheduled to appear after the second if/when the loop is vectorized. It may be augmented with additional pairs if needed in order to handle Phi as a first-order recurrence.

Definition at line 603 of file LoopUtils.cpp.

References llvm::LoopBase< BlockT, LoopT >::contains(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT, BucketT >, KeyT, ValueT, KeyInfoT, BucketT >::count(), llvm::DominatorTree::dominates(), llvm::dyn_cast(), llvm::PHINode::getBasicBlockIndex(), llvm::LoopBase< BlockT, LoopT >::getHeader(), llvm::PHINode::getIncomingValueForBlock(), llvm::LoopBase< BlockT, LoopT >::getLoopLatch(), llvm::LoopBase< BlockT, LoopT >::getLoopPreheader(), llvm::PHINode::getNumIncomingValues(), llvm::Instruction::getParent(), llvm::Value::hasOneUse(), I, llvm::Instruction::user_back(), and llvm::Value::users().

Referenced by hasOutsideLoopUser().

◆ isFloatingPointRecurrenceKind()

bool RecurrenceDescriptor::isFloatingPointRecurrenceKind ( RecurrenceKind  Kind)
static

Returns true if the recurrence kind is a floating point kind.

Definition at line 65 of file LoopUtils.cpp.

◆ isIntegerRecurrenceKind()

bool RecurrenceDescriptor::isIntegerRecurrenceKind ( RecurrenceKind  Kind)
static

Returns true if the recurrence kind is an integer kind.

Definition at line 50 of file LoopUtils.cpp.

◆ isMinMaxSelectCmpPattern()

RecurrenceDescriptor::InstDesc RecurrenceDescriptor::isMinMaxSelectCmpPattern ( Instruction I,
InstDesc Prev 
)
static

Returns a struct describing if the instruction if the instruction is a Select(ICmp(X, Y), X, Y) instruction pattern corresponding to a min(X, Y) or max(X, Y).

Returns true if the instruction is a Select(ICmp(X, Y), X, Y) instruction pattern corresponding to a min(X, Y) or max(X, Y).

Definition at line 444 of file LoopUtils.cpp.

References assert(), llvm::dyn_cast(), llvm::RecurrenceDescriptor::InstDesc::getMinMaxKind(), llvm::User::getOperand(), llvm::Value::hasOneUse(), llvm::PatternMatch::m_OrdFMax(), llvm::PatternMatch::m_OrdFMin(), llvm::PatternMatch::m_SMax(), llvm::PatternMatch::m_SMin(), llvm::PatternMatch::m_UMax(), llvm::PatternMatch::m_UMin(), llvm::PatternMatch::m_UnordFMax(), llvm::PatternMatch::m_UnordFMin(), llvm::PatternMatch::m_Value(), llvm::MCID::Select, and llvm::Value::user_begin().

◆ isRecurrenceInstr()

RecurrenceDescriptor::InstDesc RecurrenceDescriptor::isRecurrenceInstr ( Instruction I,
RecurrenceKind  Kind,
InstDesc Prev,
bool  HasFunNoNaNAttr 
)
static

Returns a struct describing if the instruction 'I' can be a recurrence variable of type 'Kind'.

If the recurrence is a min/max pattern of select(icmp()) this function advances the instruction pointer 'I' from the compare instruction to the select instruction and stores this pointer in 'PatternLastInst' member of the returned struct.

Definition at line 493 of file LoopUtils.cpp.

References llvm::MCID::Add, llvm::RecurrenceDescriptor::InstDesc::getMinMaxKind(), llvm::Instruction::getOpcode(), llvm::Value::getType(), llvm::RecurrenceDescriptor::InstDesc::getUnsafeAlgebraInst(), llvm::Instruction::isFast(), llvm::Type::isFloatingPointTy(), and llvm::MCID::Select.

◆ isReductionPHI()

bool RecurrenceDescriptor::isReductionPHI ( PHINode Phi,
Loop TheLoop,
RecurrenceDescriptor RedDes,
DemandedBits DB = nullptr,
AssumptionCache AC = nullptr,
DominatorTree DT = nullptr 
)
static

Returns true if Phi is a reduction in TheLoop.

The RecurrenceDescriptor is returned in RedDes. If either DB is non-null or AC and DT are non-null, the minimal bit width needed to compute the reduction will be computed.

Definition at line 544 of file LoopUtils.cpp.

References llvm::dbgs(), DEBUG, F(), llvm::Function::getFnAttribute(), llvm::LoopBase< BlockT, LoopT >::getHeader(), llvm::BasicBlock::getParent(), and llvm::Attribute::getValueAsString().

Referenced by getInductionVariable(), and hasOutsideLoopUser().

◆ isSigned()

bool llvm::RecurrenceDescriptor::isSigned ( )
inline

Returns true if all source operands of the recurrence are SExtInsts.

Definition at line 241 of file LoopUtils.h.


The documentation for this class was generated from the following files: