#include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/Analysis/CmpInstAnalysis.h"
#include "llvm/CodeGen/GlobalISel/GISelChangeObserver.h"
#include "llvm/CodeGen/GlobalISel/GISelKnownBits.h"
#include "llvm/CodeGen/GlobalISel/GenericMachineInstrs.h"
#include "llvm/CodeGen/GlobalISel/LegalizerHelper.h"
#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
#include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
#include "llvm/CodeGen/GlobalISel/Utils.h"
#include "llvm/CodeGen/LowLevelTypeUtils.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterBankInfo.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetOpcodes.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/DivisionByConstantInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetMachine.h"
#include <cmath>
#include <optional>
#include <tuple>

Macros
#define	DEBUG_TYPE "gi-combiner"

Functions
static unsigned	littleEndianByteAt (const unsigned ByteWidth, const unsigned I)

static Register	buildLogBase2 (Register V, MachineIRBuilder &MIB)
	Determines the LogBase2 value for a non-null input value using the transform: LogBase2(V) = (EltBits - 1) - ctlz(V).

static unsigned	bigEndianByteAt (const unsigned ByteWidth, const unsigned I)

static std::optional< bool >	isBigEndian (const SmallDenseMap< int64_t, int64_t, 8 > &MemOffset2Idx, int64_t LowestIdx)
	Given a map from byte offsets in memory to indices in a load/store, determine if that map corresponds to a little or big endian byte pattern.

static unsigned	getExtLoadOpcForExtend (unsigned ExtOpc)

static bool	canFoldInAddressingMode (GLoadStore *MI, const TargetLowering &TLI, MachineRegisterInfo &MRI)
	Return true if 'MI' is a load or a store that may be fold it's address operand into the load / store addressing mode.

static unsigned	getIndexedOpc (unsigned LdStOpc)

static APFloat	constantFoldFpUnary (const MachineInstr &MI, const MachineRegisterInfo &MRI, const APFloat &Val)

static Register	peekThroughBitcast (Register Reg, const MachineRegisterInfo &MRI)

static LLT	getMidVTForTruncRightShiftCombine (LLT ShiftTy, LLT TruncTy)

static bool	isConstValidTrue (const TargetLowering &TLI, unsigned ScalarSizeBits, int64_t Cst, bool IsVector, bool IsFP)

static std::optional< std::pair< GZExtLoad *, int64_t > >	matchLoadAndBytePosition (Register Reg, unsigned MemSizeInBits, const MachineRegisterInfo &MRI)
	Helper function for findLoadOffsetsForLoadOrCombine.

static bool	isContractableFMul (MachineInstr &MI, bool AllowFusionGlobally)
	Checks if `MI` is TargetOpcode::G_FMUL and contractable either due to global flags or MachineInstr flags.

static bool	hasMoreUses (const MachineInstr &MI0, const MachineInstr &MI1, const MachineRegisterInfo &MRI)

static std::optional< unsigned >	getMinUselessShift (KnownBits ValueKB, unsigned Opcode, std::optional< int64_t > &Result)
	Return the minimum useless shift amount that results in complete loss of the source value.

static void	commuteMask (MutableArrayRef< int > Mask, const unsigned NumElems)

Variables
static cl::opt< bool >	ForceLegalIndexing ("force-legal-indexing", cl::Hidden, cl::init(false), cl::desc("Force all indexed operations to be " "legal for the GlobalISel combiner"))

static cl::opt< unsigned >	PostIndexUseThreshold ("post-index-use-threshold", cl::Hidden, cl::init(32), cl::desc("Number of uses of a base pointer to check before it is no longer " "considered for post-indexing."))

Macro Definition Documentation

◆ DEBUG_TYPE

#define DEBUG_TYPE "gi-combiner"

Definition at line 44 of file CombinerHelper.cpp.

Function Documentation

◆ bigEndianByteAt()

static unsigned bigEndianByteAt	(	const unsigned	ByteWidth,
		const unsigned	I
	)

static

Returns: The big endian in-memory byte position of byte I in a ByteWidth bytes wide type.

E.g. Given a 4-byte type x, x[0] -> byte 3

Definition at line 104 of file CombinerHelper.cpp.

References assert(), and I.

Referenced by isBigEndian(), and llvm::CombinerHelper::matchLoadOrCombine().

◆ buildLogBase2()

static Register buildLogBase2	(	Register	V,
		MachineIRBuilder &	MIB
	)

static

Determines the LogBase2 value for a non-null input value using the transform: LogBase2(V) = (EltBits - 1) - ctlz(V).

Definition at line 92 of file CombinerHelper.cpp.

References llvm::sampleprof::Base, llvm::MachineIRBuilder::buildConstant(), llvm::MachineIRBuilder::buildCTLZ(), llvm::MachineIRBuilder::buildSub(), llvm::MachineIRBuilder::getMRI(), llvm::MachineInstrBuilder::getReg(), llvm::LLT::getScalarSizeInBits(), and MRI.

Referenced by llvm::CombinerHelper::applyUMulHToLShr().

◆ canFoldInAddressingMode()

static bool canFoldInAddressingMode	(	GLoadStore *	MI,
		const TargetLowering &	TLI,
		MachineRegisterInfo &	MRI
	)

static

Return true if 'MI' is a load or a store that may be fold it's address operand into the load / store addressing mode.

Definition at line 1127 of file CombinerHelper.cpp.

References Addr, llvm::TargetLoweringBase::AddrMode::BaseOffs, llvm::getIConstantVRegVal(), llvm::getTypeForLLT(), llvm::TargetLoweringBase::AddrMode::HasBaseReg, llvm::TargetLoweringBase::isLegalAddressingMode(), MI, MRI, and llvm::TargetLoweringBase::AddrMode::Scale.

Referenced by shouldCombineToPostInc().

◆ commuteMask()

static void commuteMask	(	MutableArrayRef< int >	Mask,
		const unsigned	NumElems
	)

static

Definition at line 7864 of file CombinerHelper.cpp.

References I, and Idx.

Referenced by llvm::CombinerHelper::matchShuffleDisjointMask().

◆ constantFoldFpUnary()

static APFloat constantFoldFpUnary	(	const MachineInstr &	MI,
		const MachineRegisterInfo &	MRI,
		const APFloat &	Val
	)

static

Definition at line 1669 of file CombinerHelper.cpp.

References llvm::getFltSemanticForLLT(), llvm::APFloat::getSemantics(), llvm::APFloatBase::IEEEdouble(), llvm_unreachable, llvm::log2(), MI, MRI, and llvm::APFloatBase::rmNearestTiesToEven.

Referenced by llvm::CombinerHelper::applyCombineConstantFoldFpUnary().

◆ getExtLoadOpcForExtend()

static unsigned getExtLoadOpcForExtend ( unsigned ExtOpc )

static

Definition at line 703 of file CombinerHelper.cpp.

References llvm_unreachable.

Referenced by llvm::CombinerHelper::applyCombineExtendingLoads(), and llvm::CombinerHelper::matchCombineExtendingLoads().

◆ getIndexedOpc()

static unsigned getIndexedOpc ( unsigned LdStOpc )

static

Definition at line 1148 of file CombinerHelper.cpp.

References llvm_unreachable.

Referenced by llvm::CombinerHelper::applyCombineIndexedLoadStore().

◆ getMidVTForTruncRightShiftCombine()

static LLT getMidVTForTruncRightShiftCombine	(	LLT	ShiftTy,
		LLT	TruncTy
	)

static

Definition at line 2588 of file CombinerHelper.cpp.

References llvm::LLT::changeElementSize(), and llvm::LLT::getScalarSizeInBits().

Referenced by llvm::CombinerHelper::matchCombineTruncOfShift().

◆ getMinUselessShift()

static std::optional< unsigned > getMinUselessShift	(	KnownBits	ValueKB,
		unsigned	Opcode,
		std::optional< int64_t > &	Result
	)

static

Return the minimum useless shift amount that results in complete loss of the source value.

Return std::nullopt when it cannot determine a value.

Definition at line 6596 of file CombinerHelper.cpp.

References assert(), llvm::KnownBits::countMinLeadingOnes(), llvm::KnownBits::countMinLeadingZeros(), llvm::KnownBits::countMinTrailingZeros(), llvm::KnownBits::getBitWidth(), llvm::KnownBits::isNegative(), and llvm::KnownBits::isNonNegative().

Referenced by llvm::CombinerHelper::matchShiftsTooBig().

◆ hasMoreUses()

static bool hasMoreUses	(	const MachineInstr &	MI0,
		const MachineInstr &	MI1,
		const MachineRegisterInfo &	MRI
	)

static

Definition at line 5758 of file CombinerHelper.cpp.

References llvm::MachineInstr::getOperand(), llvm::MachineOperand::getReg(), and MRI.

Referenced by llvm::CombinerHelper::matchCombineFAddFMAFMulToFMadOrFMA(), llvm::CombinerHelper::matchCombineFAddFMulToFMadOrFMA(), llvm::CombinerHelper::matchCombineFAddFpExtFMulToFMadOrFMA(), llvm::CombinerHelper::matchCombineFAddFpExtFMulToFMadOrFMAAggressive(), and llvm::CombinerHelper::matchCombineFSubFMulToFMadOrFMA().

◆ isBigEndian()

static std::optional< bool > isBigEndian	(	const SmallDenseMap< int64_t, int64_t, 8 > &	MemOffset2Idx,
		int64_t	LowestIdx
	)

static

Given a map from byte offsets in memory to indices in a load/store, determine if that map corresponds to a little or big endian byte pattern.

Parameters

MemOffset2Idx	maps memory offsets to address offsets.
LowestIdx	is the lowest index in `MemOffset2Idx`.

Returns: true if the map corresponds to a big endian byte pattern, false if it corresponds to a little endian byte pattern, and std::nullopt otherwise.

E.g. given a 32-bit type x, and x[AddrOffset], the in-memory byte patterns are as follows:

AddrOffset Little endian Big endian 0 0 3 1 1 2 2 2 1 3 3 0

Definition at line 127 of file CombinerHelper.cpp.

References assert(), bigEndianByteAt(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::end(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::find(), Idx, littleEndianByteAt(), and llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::size().

Referenced by collectInsertionElements(), createGPRPairNodei64(), llvm::SelectionDAG::getConstant(), llvm::CombinerHelper::matchLoadOrCombine(), PerformSTORECombine(), llvm::LegalizerHelper::reduceLoadStoreWidth(), ReplaceCMP_SWAP_64Results(), and llvm::orc::OrcMips32_Base::writeResolverCode().

◆ isConstValidTrue()

static bool isConstValidTrue	(	const TargetLowering &	TLI,
		unsigned	ScalarSizeBits,
		int64_t	Cst,
		bool	IsVector,
		bool	IsFP
	)

static

Definition at line 3373 of file CombinerHelper.cpp.

References llvm::isConstTrueVal().

Referenced by llvm::CombinerHelper::matchNotCmp().

◆ isContractableFMul()

static bool isContractableFMul	(	MachineInstr &	MI,
		bool	AllowFusionGlobally
	)

static

Checks if MI is TargetOpcode::G_FMUL and contractable either due to global flags or MachineInstr flags.

Definition at line 5752 of file CombinerHelper.cpp.

References llvm::MachineInstr::FmContract, and MI.

◆ littleEndianByteAt()

static unsigned littleEndianByteAt	(	const unsigned	ByteWidth,
		const unsigned	I
	)

static

Returns: The little endian in-memory byte position of byte I in a ByteWidth bytes wide type.

E.g. Given a 4-byte type x, x[0] -> byte 0

Definition at line 85 of file CombinerHelper.cpp.

References assert(), and I.

Referenced by isBigEndian(), and llvm::CombinerHelper::matchLoadOrCombine().

◆ matchLoadAndBytePosition()

static std::optional< std::pair< GZExtLoad *, int64_t > > matchLoadAndBytePosition	(	Register	Reg,
		unsigned	MemSizeInBits,
		const MachineRegisterInfo &	MRI
	)

static

Helper function for findLoadOffsetsForLoadOrCombine.

Check if Reg is the result of loading a MemSizeInBits wide value, and then moving that value into a specific byte offset.

e.g. x[i] << 24

Returns: The load instruction and the byte offset it is moved into.

Definition at line 3840 of file CombinerHelper.cpp.

References assert(), llvm::MIPatternMatch::m_GShl(), llvm::MIPatternMatch::m_ICst(), llvm::MIPatternMatch::m_OneNonDBGUse(), llvm::MIPatternMatch::m_Reg(), llvm::MIPatternMatch::mi_match(), and MRI.

◆ peekThroughBitcast()

static Register peekThroughBitcast	(	Register	Reg,
		const MachineRegisterInfo &	MRI
	)

static

Definition at line 2154 of file CombinerHelper.cpp.

References llvm::MIPatternMatch::m_GBitcast(), llvm::MIPatternMatch::m_Reg(), llvm::MIPatternMatch::mi_match(), and MRI.

Referenced by llvm::CombinerHelper::matchCombineUnmergeMergeToPlainValues().

Variable Documentation

◆ ForceLegalIndexing

cl::opt< bool > ForceLegalIndexing("force-legal-indexing", cl::Hidden, cl::init(false), cl::desc("Force all indexed operations to be " "legal for the GlobalISel combiner"))	(	"force-legal-indexing"	,
		cl::Hidden	,
		cl::init(false)	,
		cl::desc("Force all indexed operations to be " "legal for the GlobalISel combiner")
	)

static

◆ PostIndexUseThreshold

cl::opt< unsigned > PostIndexUseThreshold("post-index-use-threshold", cl::Hidden, cl::init(32), cl::desc("Number of uses of a base pointer to check before it is no longer " "considered for post-indexing."))	(	"post-index-use-threshold"	,
		cl::Hidden	,
		cl::init(32)	,
		cl::desc("Number of uses of a base pointer to check before it is no longer " "considered for post-indexing.")
	)

static

Macros

Functions

Variables

Macro Definition Documentation

◆ DEBUG_TYPE

Function Documentation

◆ bigEndianByteAt()

◆ buildLogBase2()

◆ canFoldInAddressingMode()

◆ commuteMask()

◆ constantFoldFpUnary()

◆ getExtLoadOpcForExtend()

◆ getIndexedOpc()

◆ getMidVTForTruncRightShiftCombine()

◆ getMinUselessShift()

◆ hasMoreUses()

◆ isBigEndian()

◆ isConstValidTrue()

◆ isContractableFMul()

◆ littleEndianByteAt()

◆ matchLoadAndBytePosition()

◆ peekThroughBitcast()

Variable Documentation

◆ ForceLegalIndexing

◆ PostIndexUseThreshold