The analysis. More...

#include "llvm/Analysis/HashRecognize.h"

Public Member Functions
	HashRecognize (const Loop &L, ScalarEvolution &SE)
std::variant< PolynomialInfo, StringRef >	recognizeCRC () const
	The main entry point for analyzing a loop and recognizing the CRC algorithm.
std::optional< PolynomialInfo >	getResult () const
void	print (raw_ostream &OS) const
LLVM_DUMP_METHOD void	dump () const

Static Public Member Functions
static CRCTable	genSarwateTable (const APInt &GenPoly, bool ByteOrderSwapped)
	Generate a lookup table of 256 entries by interleaving the generating polynomial.

Detailed Description

The analysis.

Definition at line 74 of file HashRecognize.h.

Constructor & Destructor Documentation

◆ HashRecognize()

HashRecognize::HashRecognize	(	const Loop &	L,
		ScalarEvolution &	SE )

Definition at line 579 of file HashRecognize.cpp.

Referenced by getResult().

Member Function Documentation

◆ dump()

void HashRecognize::dump ( ) const

Definition at line 569 of file HashRecognize.cpp.

References llvm::dbgs(), and print().

◆ genSarwateTable()

CRCTable HashRecognize::genSarwateTable	(	const APInt &	GenPoly,
		bool	ByteOrderSwapped )

static

Generate a lookup table of 256 entries by interleaving the generating polynomial.

The optimization technique of table-lookup for CRC is also called the Sarwate algorithm.

Definition at line 353 of file HashRecognize.cpp.

References llvm::APInt::getBitWidth(), llvm::APInt::getSignedMinValue(), llvm::APInt::getZero(), I, llvm::APInt::isSignBitSet(), llvm::APInt::lshr(), and llvm::APInt::shl().

Referenced by print().

◆ getResult()

std::optional< PolynomialInfo > HashRecognize::getResult ( ) const

Definition at line 572 of file HashRecognize.cpp.

References HashRecognize().

◆ print()

void HashRecognize::print ( raw_ostream & OS ) const

Definition at line 532 of file HashRecognize.cpp.

References genSarwateTable(), llvm::raw_ostream::indent(), llvm::CRCTable::print(), and recognizeCRC().

Referenced by dump(), and llvm::HashRecognizePrinterPass::run().

◆ recognizeCRC()

std::variant< PolynomialInfo, StringRef > HashRecognize::recognizeCRC ( ) const

The main entry point for analyzing a loop and recognizing the CRC algorithm.

Returns a PolynomialInfo on success, and a StringRef on failure.

Definition at line 440 of file HashRecognize.cpp.

References assert(), llvm::cast(), containsUnreachable(), llvm::PHINode::getIncomingValueForBlock(), llvm::Type::getIntegerBitWidth(), getRecurrences(), llvm::BasicBlock::getTerminator(), llvm::Value::getType(), isBigEndianBitShift(), isConditionalOnXorOfPHIs(), isSignificantBitCheckWellFormed(), llvm::none_of(), and llvm::SmallVectorTemplateBase< T, bool >::push_back().