LLVM  8.0.0svn
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/Analysis/IVDescriptors.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 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 63 of file IVDescriptors.h.

Member Enumeration Documentation

◆ MinMaxRecurrenceKind

Enumerator
MRK_Invalid 
MRK_UIntMin 
MRK_UIntMax 
MRK_SIntMin 
MRK_SIntMax 
MRK_FloatMin 
MRK_FloatMax 

Definition at line 80 of file IVDescriptors.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 66 of file IVDescriptors.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

Definition at line 92 of file IVDescriptors.h.

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

Returns true if Phi is a reduction of type Kind and adds it to the RecurrenceDescriptor.

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 191 of file IVDescriptors.cpp.

References llvm::LoopBase< BlockT, LoopT >::getHeader(), llvm::PHINode::getIncomingValueForBlock(), llvm::LoopBase< BlockT, LoopT >::getLoopPreheader(), llvm::PHINode::getNumIncomingValues(), llvm::Instruction::getParent(), and llvm::Value::getType().

Referenced by llvm::RecurrenceDescriptor::InstDesc::getPatternInst(), and MatchReductions().

◆ 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 44 of file IVDescriptors.cpp.

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

Referenced by llvm::RecurrenceDescriptor::InstDesc::getPatternInst().

◆ getCastInsts()

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

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

Definition at line 223 of file IVDescriptors.h.

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

◆ getLoopExitInstr()

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

Definition at line 199 of file IVDescriptors.h.

Referenced by llvm::LoopVectorizationLegality::isUniform().

◆ getMinMaxRecurrenceKind()

MinMaxRecurrenceKind llvm::RecurrenceDescriptor::getMinMaxRecurrenceKind ( )
inline

Definition at line 195 of file IVDescriptors.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 686 of file IVDescriptors.cpp.

References llvm::MCID::Add, llvm::InductionDescriptor::InductionDescriptor(), and llvm_unreachable.

Referenced by llvm::InnerLoopVectorizer::fixReduction(), and llvm::RecurrenceDescriptor::InstDesc::getPatternInst().

◆ 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 660 of file IVDescriptors.cpp.

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

Referenced by llvm::InnerLoopVectorizer::fixReduction(), and llvm::RecurrenceDescriptor::InstDesc::getPatternInst().

◆ getRecurrenceKind()

RecurrenceKind llvm::RecurrenceDescriptor::getRecurrenceKind ( )
inline

◆ getRecurrenceStartValue()

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

Definition at line 197 of file IVDescriptors.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 219 of file IVDescriptors.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 206 of file IVDescriptors.h.

References isArithmeticRecurrenceKind(), isFloatingPointRecurrenceKind(), and isIntegerRecurrenceKind().

Referenced by llvm::LoopVectorizationLegality::isUniform().

◆ hasMultipleUsesOf()

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

Returns true if instruction I has multiple uses in Insts.

Definition at line 533 of file IVDescriptors.cpp.

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

Referenced by llvm::RecurrenceDescriptor::InstDesc::getPatternInst().

◆ hasUnsafeAlgebra()

bool llvm::RecurrenceDescriptor::hasUnsafeAlgebra ( )
inline

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

Definition at line 203 of file IVDescriptors.h.

Referenced by llvm::LoopVectorizationLegality::isUniform().

◆ isArithmeticRecurrenceKind()

bool RecurrenceDescriptor::isArithmeticRecurrenceKind ( RecurrenceKind  Kind)
static

Returns true if the recurrence kind is an arithmetic kind.

Definition at line 71 of file IVDescriptors.cpp.

Referenced by getUnsafeAlgebraInst().

◆ 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 606 of file IVDescriptors.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 llvm::RecurrenceDescriptor::InstDesc::getPatternInst(), and llvm::LoopVectorizationLegality::isUniform().

◆ isFloatingPointRecurrenceKind()

bool RecurrenceDescriptor::isFloatingPointRecurrenceKind ( RecurrenceKind  Kind)
static

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

Definition at line 67 of file IVDescriptors.cpp.

Referenced by getUnsafeAlgebraInst().

◆ isIntegerRecurrenceKind()

bool RecurrenceDescriptor::isIntegerRecurrenceKind ( RecurrenceKind  Kind)
static

Returns true if the recurrence kind is an integer kind.

Definition at line 52 of file IVDescriptors.cpp.

Referenced by getUnsafeAlgebraInst().

◆ 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 446 of file IVDescriptors.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().

Referenced by llvm::RecurrenceDescriptor::InstDesc::getPatternInst().

◆ 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 495 of file IVDescriptors.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.

Referenced by llvm::RecurrenceDescriptor::InstDesc::getPatternInst().

◆ 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 546 of file IVDescriptors.cpp.

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

Referenced by findInnerReductionPhi(), llvm::RecurrenceDescriptor::InstDesc::getPatternInst(), and llvm::LoopVectorizationLegality::isUniform().

◆ isSigned()

bool llvm::RecurrenceDescriptor::isSigned ( )
inline

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

Definition at line 226 of file IVDescriptors.h.

References MRK_Invalid, and RK_NoRecurrence.


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