LazyValueInfo.cpp File Reference

#include "llvm/Analysis/LazyValueInfo.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/ValueLattice.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/AssemblyAnnotationWriter.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/raw_ostream.h"
#include <optional>

Include dependency graph for LazyValueInfo.cpp:

Go to the source code of this file.

Namespaces
	llvm
	This is an optimization pass for GlobalISel generic memory operations.

Macros
#define	DEBUG_TYPE   "lazy-value-info"

Typedefs
typedef PointerIntPair< Value *, 1, bool >	CondValue

Functions
	INITIALIZE_PASS_BEGIN (LazyValueInfoWrapperPass, "lazy-value-info", "Lazy Value Information Analysis", false, true) INITIALIZE_PASS_END(LazyValueInfoWrapperPass
FunctionPass *	llvm::createLazyValueInfoPass ()
	createLazyValueInfoPass - This creates an instance of the LazyValueInfo pass. More...
static bool	hasSingleValue (const ValueLatticeElement &Val)
	Returns true if this lattice value represents at most one possible value. More...
static ValueLatticeElement	intersect (const ValueLatticeElement &A, const ValueLatticeElement &B)
	Combine two sets of facts about the same value into a single set of facts. More...
static ValueLatticeElement	getFromRangeMetadata (Instruction *BBI)
static void	AddNonNullPointer (Value *Ptr, NonNullPointerSet &PtrSet)
static void	AddNonNullPointersByInstruction (Instruction *I, NonNullPointerSet &PtrSet)
static ValueLatticeElement	getValueFromCondition (Value *Val, Value *Cond, bool isTrueDest=true)
static ConstantRange	getConstantRangeOrFull (const ValueLatticeElement &Val, Type *Ty, const DataLayout &DL)
static bool	matchICmpOperand (APInt &Offset, Value *LHS, Value *Val, ICmpInst::Predicate Pred)
static ValueLatticeElement	getValueFromSimpleICmpCondition (CmpInst::Predicate Pred, Value *RHS, const APInt &Offset)
	Get value range for a "(Val + Offset) Pred RHS" condition. More...
static ValueLatticeElement	getValueFromICmpCondition (Value *Val, ICmpInst *ICI, bool isTrueDest)
static ValueLatticeElement	getValueFromOverflowCondition (Value *Val, WithOverflowInst *WO, bool IsTrueDest)
static std::optional< ValueLatticeElement >	getValueFromConditionImpl (Value *Val, CondValue CondVal, bool isRevisit, SmallDenseMap< CondValue, ValueLatticeElement > &Visited, SmallVectorImpl< CondValue > &Worklist)
static bool	usesOperand (User *Usr, Value *Op)
static bool	isOperationFoldable (User *Usr)
static ValueLatticeElement	constantFoldUser (User *Usr, Value *Op, const APInt &OpConstVal, const DataLayout &DL)
static std::optional< ValueLatticeElement >	getEdgeValueLocal (Value *Val, BasicBlock *BBFrom, BasicBlock *BBTo)
	Compute the value of Val on the edge BBFrom -> BBTo. More...
static LazyValueInfoImpl &	getImpl (void *&PImpl, AssumptionCache *AC, const Module *M)
	This lazily constructs the LazyValueInfoImpl. More...
static bool	isKnownNonConstant (Value *V)
	Returns true if we can statically tell that this value will never be a "useful" constant. More...
static LazyValueInfo::Tristate	getPredicateResult (unsigned Pred, Constant *C, const ValueLatticeElement &Val, const DataLayout &DL, TargetLibraryInfo *TLI)
	INITIALIZE_PASS_BEGIN (LazyValueInfoPrinter, "print-lazy-value-info", "Lazy Value Info Printer Pass", false, false) INITIALIZE_PASS_END(LazyValueInfoPrinter

Variables
static const unsigned	MaxProcessedPerValue = 500
lazy value	info
lazy value Lazy Value Information	Analysis
lazy value Lazy Value Information	false
print lazy value Lazy Value Info Printer	Pass

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "lazy-value-info"

Definition at line 44 of file LazyValueInfo.cpp.

Typedef Documentation

CondValue

typedef PointerIntPair<Value *, 1, bool> CondValue

Definition at line 1172 of file LazyValueInfo.cpp.

Function Documentation

AddNonNullPointer()

static void AddNonNullPointer ( Value *  Ptr, NonNullPointerSet &  PtrSet  )

static

Definition at line 636 of file LazyValueInfo.cpp.

References llvm::getUnderlyingObject(), and Ptr.

Referenced by AddNonNullPointersByInstruction().

AddNonNullPointersByInstruction()

static void AddNonNullPointersByInstruction ( Instruction *  I, NonNullPointerSet &  PtrSet  )

static

Definition at line 642 of file LazyValueInfo.cpp.

References AddNonNullPointer(), I, MI, and S.

constantFoldUser()

static ValueLatticeElement constantFoldUser ( User *  Usr, Value *  Op, const APInt &  OpConstVal, const DataLayout &  DL  )

static

Definition at line 1288 of file LazyValueInfo.cpp.

References assert(), DL, llvm::CastInst::getDestTy(), llvm::Constant::getIntegerValue(), llvm::BinaryOperator::getOpcode(), llvm::CastInst::getOpcode(), llvm::User::getOperand(), llvm::ValueLatticeElement::getOverdefined(), llvm::ValueLatticeElement::getRange(), isOperationFoldable(), LHS, RHS, llvm::simplifyBinOp(), and llvm::simplifyCastInst().

Referenced by getEdgeValueLocal().

getConstantRangeOrFull()

static ConstantRange getConstantRangeOrFull ( const ValueLatticeElement &  Val, Type *  Ty, const DataLayout &  DL  )

static

Definition at line 801 of file LazyValueInfo.cpp.

References DL, llvm::ValueLatticeElement::getConstantRange(), and llvm::ValueLatticeElement::isConstantRange().

getEdgeValueLocal()

static std::optional<ValueLatticeElement> getEdgeValueLocal ( Value *  Val, BasicBlock *  BBFrom, BasicBlock *  BBTo  )

static

Compute the value of Val on the edge BBFrom -> BBTo.

Returns false if Val is not constrained on the edge. Result is unspecified if return value is false.

Definition at line 1322 of file LazyValueInfo.cpp.

References llvm::ValueLatticeElement::asConstantInteger(), assert(), llvm::BitWidth, constantFoldUser(), llvm::ConstantRange::difference(), DL, llvm::ConstantInt::get(), llvm::ValueLatticeElement::get(), llvm::ValueLatticeElement::getConstantRange(), llvm::Value::getContext(), llvm::Module::getDataLayout(), llvm::Type::getInt1Ty(), llvm::Type::getIntegerBitWidth(), llvm::BasicBlock::getModule(), llvm::ValueLatticeElement::getRange(), llvm::BasicBlock::getTerminator(), llvm::Value::getType(), getValueFromCondition(), i, isOperationFoldable(), llvm::ValueLatticeElement::isOverdefined(), move, SI, llvm::ConstantRange::unionWith(), and usesOperand().

Referenced by llvm::LazyValueInfo::getConstantRangeAtUse().

getFromRangeMetadata()

static ValueLatticeElement getFromRangeMetadata ( Instruction *  BBI )

static

Definition at line 559 of file LazyValueInfo.cpp.

References llvm::MCID::Call, llvm::getConstantRangeFromMetadata(), llvm::Instruction::getMetadata(), llvm::Instruction::getOpcode(), llvm::ValueLatticeElement::getOverdefined(), llvm::ValueLatticeElement::getRange(), llvm::Value::getType(), and llvm::SPII::Load.

getImpl()

static LazyValueInfoImpl& getImpl ( void *&  PImpl, AssumptionCache *  AC, const Module *  M  )

static

This lazily constructs the LazyValueInfoImpl.

Definition at line 1542 of file LazyValueInfo.cpp.

References assert(), DL, llvm::Intrinsic::getName(), and M.

Referenced by llvm::AttributeList::addParamAttribute(), llvm::LazyValueInfo::clear(), llvm::LazyValueInfo::eraseBlock(), llvm::AttributeList::get(), llvm::MDTuple::get(), llvm::LazyValueInfo::getConstant(), llvm::LazyValueInfo::getConstantOnEdge(), llvm::LazyValueInfo::getConstantRange(), llvm::LazyValueInfo::getConstantRangeOnEdge(), llvm::DIAssignID::getDistinct(), llvm::MDTuple::getDistinct(), llvm::MDTuple::getIfExists(), llvm::LazyValueInfo::getPredicateAt(), llvm::LazyValueInfo::getPredicateOnEdge(), llvm::DIAssignID::getTemporary(), llvm::MDTuple::getTemporary(), llvm::LazyValueInfo::printLVI(), llvm::LazyValueInfo::releaseMemory(), llvm::LazyValueInfoWrapperPass::runOnFunction(), and llvm::LazyValueInfo::threadEdge().

getPredicateResult()

static LazyValueInfo::Tristate getPredicateResult ( unsigned  Pred, Constant *  C, const ValueLatticeElement &  Val, const DataLayout &  DL, TargetLibraryInfo *  TLI  )

static

Definition at line 1737 of file LazyValueInfo.cpp.

References llvm::ConstantFoldCompareInstOperands(), llvm::ConstantRange::contains(), DL, llvm::LazyValueInfo::False, llvm::ValueLatticeElement::getConstant(), llvm::ValueLatticeElement::getConstantRange(), llvm::ValueLatticeElement::getNotConstant(), llvm::ConstantInt::getValue(), llvm::CmpInst::ICMP_EQ, llvm::CmpInst::ICMP_NE, llvm::ConstantRange::inverse(), llvm::ValueLatticeElement::isConstant(), llvm::ValueLatticeElement::isConstantRange(), llvm::ValueLatticeElement::isNotConstant(), llvm::Constant::isNullValue(), llvm::ConstantRange::isSingleElement(), llvm::ConstantRange::makeExactICmpRegion(), llvm::LazyValueInfo::True, and llvm::LazyValueInfo::Unknown.

Referenced by llvm::LazyValueInfo::getPredicateAt(), and llvm::LazyValueInfo::getPredicateOnEdge().

getValueFromCondition()

ValueLatticeElement getValueFromCondition ( Value *  Val, Value *  Cond, bool  isTrueDest = true  )

static

Definition at line 1240 of file LazyValueInfo.cpp.

References assert(), Cond, llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, 4, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::end(), llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, 4, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::find(), llvm::ValueLatticeElement::getOverdefined(), getValueFromConditionImpl(), and llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, 4, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::try_emplace().

Referenced by llvm::LazyValueInfo::getConstantRangeAtUse(), and getEdgeValueLocal().

getValueFromConditionImpl()

static std::optional<ValueLatticeElement> getValueFromConditionImpl ( Value *  Val, CondValue  CondVal, bool  isRevisit, SmallDenseMap< CondValue, ValueLatticeElement > &  Visited, SmallVectorImpl< CondValue > &  Worklist  )

static

Definition at line 1174 of file LazyValueInfo.cpp.

References assert(), Cond, llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, 4, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::end(), llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, 4, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::find(), llvm::ExtractValueInst::getAggregateOperand(), llvm::PointerIntPair< PointerTy, IntBits, IntType, PtrTraits, Info >::getInt(), llvm::ExtractValueInst::getNumIndices(), llvm::ValueLatticeElement::getOverdefined(), llvm::PointerIntPair< PointerTy, IntBits, IntType, PtrTraits, Info >::getPointer(), getValueFromICmpCondition(), getValueFromOverflowCondition(), llvm::ExtractValueInst::idx_begin(), intersect(), llvm::ValueLatticeElement::isOverdefined(), llvm::PatternMatch::m_LogicalAnd(), llvm::PatternMatch::m_LogicalOr(), llvm::MIPatternMatch::m_Not(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), llvm::ValueLatticeElement::mergeIn(), and N.

Referenced by getValueFromCondition().

getValueFromICmpCondition()

static ValueLatticeElement getValueFromICmpCondition ( Value *  Val, ICmpInst *  ICI, bool  isTrueDest  )

static

Definition at line 1081 of file LazyValueInfo.cpp.

References llvm::BitWidth, llvm::ConstantRange::fromKnownBits(), llvm::ValueLatticeElement::get(), llvm::CmpInst::getInversePredicate(), llvm::ConstantRange::getNonEmpty(), llvm::ValueLatticeElement::getNot(), llvm::APInt::getOneBitSet(), llvm::User::getOperand(), llvm::ValueLatticeElement::getOverdefined(), llvm::CmpInst::getPredicate(), llvm::ValueLatticeElement::getRange(), llvm::Type::getScalarSizeInBits(), llvm::CmpInst::getSwappedPredicate(), llvm::Value::getType(), llvm::ConstantRange::getUnsignedMin(), getValueFromSimpleICmpCondition(), llvm::APInt::getZero(), llvm::CmpInst::ICMP_EQ, llvm::CmpInst::ICMP_NE, llvm::ConstantRange::isEmptySet(), llvm::ICmpInst::isEquality(), llvm::Type::isIntegerTy(), LHS, llvm::PatternMatch::m_And(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_CombineOr(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_Trunc(), llvm::PatternMatch::m_URem(), llvm::PatternMatch::m_Value(), llvm::ConstantRange::makeExactICmpRegion(), llvm::BitmaskEnumDetail::Mask(), llvm::PatternMatch::match(), matchICmpOperand(), llvm::Offset, llvm::KnownBits::One, RHS, llvm::KnownBits::Zero, and llvm::APInt::zext().

Referenced by getValueFromConditionImpl().

getValueFromOverflowCondition()

static ValueLatticeElement getValueFromOverflowCondition ( Value *  Val, WithOverflowInst *  WO, bool  IsTrueDest  )

static

Definition at line 1151 of file LazyValueInfo.cpp.

References llvm::BinaryOpIntrinsic::getBinaryOp(), llvm::BinaryOpIntrinsic::getLHS(), llvm::BinaryOpIntrinsic::getNoWrapKind(), llvm::ValueLatticeElement::getOverdefined(), llvm::ValueLatticeElement::getRange(), llvm::BinaryOpIntrinsic::getRHS(), llvm::ConstantRange::inverse(), llvm::PatternMatch::m_APInt(), llvm::ConstantRange::makeExactNoWrapRegion(), and llvm::PatternMatch::match().

Referenced by getValueFromConditionImpl().

getValueFromSimpleICmpCondition()

static ValueLatticeElement getValueFromSimpleICmpCondition ( CmpInst::Predicate  Pred, Value *  RHS, const APInt &  Offset  )

static

Get value range for a "(Val + Offset) Pred RHS" condition.

Definition at line 1066 of file LazyValueInfo.cpp.

References llvm::getConstantRangeFromMetadata(), llvm::Type::getIntegerBitWidth(), llvm::ValueLatticeElement::getRange(), llvm::Value::getType(), I, llvm::ConstantRange::makeAllowedICmpRegion(), llvm::Offset, RHS, and llvm::ConstantRange::subtract().

Referenced by getValueFromICmpCondition().

hasSingleValue()

static bool hasSingleValue ( const ValueLatticeElement &  Val )

static

Returns true if this lattice value represents at most one possible value.

This is as precise as any lattice value can get while still representing reachable code.

Definition at line 70 of file LazyValueInfo.cpp.

References llvm::ValueLatticeElement::getConstantRange(), llvm::ValueLatticeElement::isConstant(), llvm::ValueLatticeElement::isConstantRange(), and llvm::ConstantRange::isSingleElement().

Referenced by intersect().

INITIALIZE_PASS_BEGIN() [1/2]

INITIALIZE_PASS_BEGIN	(	LazyValueInfoPrinter	,
		"print-lazy-value-info"	,
		"Lazy Value Info Printer Pass"	,
		false	,
		false
	)

INITIALIZE_PASS_BEGIN() [2/2]

INITIALIZE_PASS_BEGIN	(	LazyValueInfoWrapperPass	,
		"lazy-value-info"	,
		"Lazy Value Information Analysis"	,
		false	,
		true
	)

intersect()

static ValueLatticeElement intersect ( const ValueLatticeElement &  A, const ValueLatticeElement &  B  )

static

Combine two sets of facts about the same value into a single set of facts.

Note that this method is not suitable for merging facts along different paths in a CFG; that's what the mergeIn function is for. This is for merging facts gathered about the same value at the same location through two independent means. Notes:

• This method does not promise to return the most precise possible lattice value implied by A and B. It is allowed to return any lattice element which is at least as strong as either A or B (unless our facts conflict, see below).
• Due to unreachable code, the intersection of two lattice values could be contradictory. If this happens, we return some valid lattice value so as not confuse the rest of LVI. Ideally, we'd always return Undefined, but we do not make this guarantee. TODO: This would be a useful enhancement.

Definition at line 95 of file LazyValueInfo.cpp.

References B, llvm::ValueLatticeElement::getRange(), hasSingleValue(), and move.

Referenced by getValueFromConditionImpl().

isKnownNonConstant()

static bool isKnownNonConstant ( Value *  V )

static

Returns true if we can statically tell that this value will never be a "useful" constant.

In practice, this means we've got something like an alloca or a malloc call for which a comparison against a constant can only be guarding dead code. Note that we are potentially giving up some precision in dead code (a constant result) in favour of avoiding a expensive search for a easily answered common query.

Definition at line 1610 of file LazyValueInfo.cpp.

References llvm::Value::stripPointerCasts().

Referenced by llvm::LazyValueInfo::getConstant().

isOperationFoldable()

static bool isOperationFoldable ( User *  Usr )

static

Definition at line 1280 of file LazyValueInfo.cpp.

Referenced by constantFoldUser(), and getEdgeValueLocal().

matchICmpOperand()

static bool matchICmpOperand ( APInt &  Offset, Value *  LHS, Value *  Val, ICmpInst::Predicate  Pred  )

static

Definition at line 1032 of file LazyValueInfo.cpp.

References llvm::CmpInst::ICMP_UGE, llvm::CmpInst::ICMP_UGT, llvm::CmpInst::ICMP_ULE, llvm::CmpInst::ICMP_ULT, LHS, llvm::PatternMatch::m_Add(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_c_And(), llvm::PatternMatch::m_c_Or(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), and llvm::Offset.

Referenced by getValueFromICmpCondition().

usesOperand()

static bool usesOperand ( User *  Usr, Value *  Op  )

static

Definition at line 1272 of file LazyValueInfo.cpp.

References llvm::is_contained(), and llvm::User::operands().

Referenced by getEdgeValueLocal().

Variable Documentation

Analysis

lazy value Lazy Value Information Analysis

Definition at line 59 of file LazyValueInfo.cpp.

false

print lazy value Lazy Value Info Printer false

Definition at line 59 of file LazyValueInfo.cpp.

info

print lazy value info

Definition at line 58 of file LazyValueInfo.cpp.

Referenced by ARM64EmitRuntimeFunction(), ARM64EmitUnwindInfo(), ARM64EmitUnwindInfoForSegment(), ARM64FindSegmentsInFunction(), ARM64ProcessEpilogs(), ARMEmitRuntimeFunction(), ARMEmitUnwindInfo(), checkARM64PackedEpilog(), checkARMPackedEpilog(), EmitRuntimeFunction(), llvm::Win64EH::UnwindEmitter::EmitUnwindInfo(), llvm::Win64EH::ARMUnwindEmitter::EmitUnwindInfo(), llvm::Win64EH::ARM64UnwindEmitter::EmitUnwindInfo(), EmitUnwindInfo(), findLiveReferences(), FindMatchingEpilog(), llvm::CCState::getInRegsParamInfo(), llvm::TargetLowering::getMultipleConstraintMatchWeight(), llvm::SparcTargetLowering::getSingleConstraintMatchWeight(), llvm::AVRTargetLowering::getSingleConstraintMatchWeight(), llvm::SystemZTargetLowering::getSingleConstraintMatchWeight(), llvm::ARMTargetLowering::getSingleConstraintMatchWeight(), llvm::PPCTargetLowering::getSingleConstraintMatchWeight(), llvm::X86TargetLowering::getSingleConstraintMatchWeight(), llvm::TargetLowering::getSingleConstraintMatchWeight(), insertParsePoints(), recomputeLiveInValues(), llvm::MachO::swapStruct(), tryARM64PackedUnwind(), and tryARMPackedUnwind().

MaxProcessedPerValue

const unsigned MaxProcessedPerValue = 500

static

Definition at line 48 of file LazyValueInfo.cpp.

Pass

print lazy value Lazy Value Info Printer Pass

Definition at line 2066 of file LazyValueInfo.cpp.

Referenced by analyzeFunction(), llvm::PreservedCFGCheckerInstrumentation::registerCallbacks(), llvm::slpvectorizer::BoUpSLP::VLOperands::reorder(), llvm::SanitizerBinaryMetadataPass::run(), llvm::PassManager< LazyCallGraph::SCC, CGSCCAnalysisManager, LazyCallGraph &, CGSCCUpdateResult & >::run(), llvm::PassManager< Loop, LoopAnalysisManager, LoopStandardAnalysisResults &, LPMUpdater & >::runSinglePass(), and llvm::MIRProfileLoader::setFSPass().