LLVM: RecurrenceInfo Struct Reference (original) (raw)

A structure that can hold either a Simple Recurrence or a Conditional Recurrence. More...

Public Member Functions
	RecurrenceInfo (const Loop &L)
	operator bool () const
void	print (raw_ostream &OS, unsigned Indent=0) const
LLVM_DUMP_METHOD void	dump () const
bool	matchSimpleRecurrence (const PHINode *P)
	Wraps llvm::matchSimpleRecurrence.
bool	matchConditionalRecurrence (const PHINode *P, Instruction::BinaryOps BOWithConstOpToMatch=Instruction::BinaryOpsEnd)
	A Conditional Recurrence is a recurrence of the form:

Public Attributes
const Loop &	L
const PHINode *	Phi = nullptr
BinaryOperator *	BO = nullptr
Value *	Start = nullptr
Value *	Step = nullptr
std::optional< APInt >	ExtraConst

A structure that can hold either a Simple Recurrence or a Conditional Recurrence.

Note that in the case of a Simple Recurrence, Step is an operand of the BO, while in a Conditional Recurrence, it is a SelectInst.

Definition at line 106 of file HashRecognize.cpp.

RecurrenceInfo::RecurrenceInfo ( const Loop & L)	inline

◆ dump()

◆ matchConditionalRecurrence()

A Conditional Recurrence is a recurrence of the form:

loop: rec = phi [start, entry], [step, loop] ... step = select _, tv, fv

where tv and fv ultimately end up using rec via the same BO instruction, after digging through the use-def chain.

ExtraConst is relevant if BOWithConstOpToMatch is supplied: when digging the use-def chain, a BinOp with opcode BOWithConstOpToMatch is matched, and ExtraConst is a constant operand of that BinOp. This peculiarity exists, because in a CRC algorithm, the BOWithConstOpToMatch is an XOR, and the ExtraConst ends up being the generating polynomial.

Definition at line 283 of file HashRecognize.cpp.

References BO, llvm::dbgs(), ExtraConst, LLVM_DEBUG, llvm::PatternMatch::m_Cmp(), llvm::PatternMatch::m_Instruction(), llvm::PatternMatch::m_Select(), llvm::SCEVPatternMatch::match(), P, Phi, Start, and Step.