LLVM  4.0.0
Functions | Variables
ValueTracking.cpp File Reference
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/VectorUtils.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/Statepoint.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include <algorithm>
#include <array>
#include <cstring>
Include dependency graph for ValueTracking.cpp:

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Functions

static unsigned getBitWidth (Type *Ty, const DataLayout &DL)
 Returns the bitwidth of the given scalar or pointer type (if unknown returns 0). More...
 
static const InstructionsafeCxtI (const Value *V, const Instruction *CxtI)
 
static void computeKnownBits (const Value *V, APInt &KnownZero, APInt &KnownOne, unsigned Depth, const Query &Q)
 Determine which bits of V are known to be either zero or one and return them in the KnownZero/KnownOne bit sets. More...
 
static void ComputeSignBit (const Value *V, bool &KnownZero, bool &KnownOne, unsigned Depth, const Query &Q)
 Determine whether the sign bit is known to be zero or one. More...
 
static bool isKnownToBeAPowerOfTwo (const Value *V, bool OrZero, unsigned Depth, const Query &Q)
 Return true if the given value is known to have exactly one bit set when defined. More...
 
static bool isKnownNonZero (const Value *V, unsigned Depth, const Query &Q)
 Return true if the given value is known to be non-zero when defined. More...
 
static bool isKnownNonEqual (const Value *V1, const Value *V2, const Query &Q)
 Return true if it is known that V1 != V2. More...
 
static bool MaskedValueIsZero (const Value *V, const APInt &Mask, unsigned Depth, const Query &Q)
 Return true if 'V & Mask' is known to be zero. More...
 
static unsigned ComputeNumSignBits (const Value *V, unsigned Depth, const Query &Q)
 Return the number of times the sign bit of the register is replicated into the other bits. More...
 
static void computeKnownBitsAddSub (bool Add, const Value *Op0, const Value *Op1, bool NSW, APInt &KnownZero, APInt &KnownOne, APInt &KnownZero2, APInt &KnownOne2, unsigned Depth, const Query &Q)
 
static void computeKnownBitsMul (const Value *Op0, const Value *Op1, bool NSW, APInt &KnownZero, APInt &KnownOne, APInt &KnownZero2, APInt &KnownOne2, unsigned Depth, const Query &Q)
 
static bool isEphemeralValueOf (const Instruction *I, const Value *E)
 
static bool isAssumeLikeIntrinsic (const Instruction *I)
 
static void computeKnownBitsFromAssume (const Value *V, APInt &KnownZero, APInt &KnownOne, unsigned Depth, const Query &Q)
 
static void computeKnownBitsFromShiftOperator (const Operator *I, APInt &KnownZero, APInt &KnownOne, APInt &KnownZero2, APInt &KnownOne2, unsigned Depth, const Query &Q, function_ref< APInt(const APInt &, unsigned)> KZF, function_ref< APInt(const APInt &, unsigned)> KOF)
 
static void computeKnownBitsFromOperator (const Operator *I, APInt &KnownZero, APInt &KnownOne, unsigned Depth, const Query &Q)
 
static bool isGEPKnownNonNull (const GEPOperator *GEP, unsigned Depth, const Query &Q)
 Test whether a GEP's result is known to be non-null. More...
 
static bool rangeMetadataExcludesValue (const MDNode *Ranges, const APInt &Value)
 Does the 'Range' metadata (which must be a valid MD_range operand list) ensure that the value it's attached to is never Value? 'RangeType' is is the type of the value described by the range. More...
 
static bool isAddOfNonZero (const Value *V1, const Value *V2, const Query &Q)
 Return true if V2 == V1 + X, where X is known non-zero. More...
 
static unsigned computeNumSignBitsVectorConstant (const Value *V, unsigned TyBits)
 For vector constants, loop over the elements and find the constant with the minimum number of sign bits. More...
 
static bool cannotBeOrderedLessThanZeroImpl (const Value *V, const TargetLibraryInfo *TLI, bool SignBitOnly, unsigned Depth)
 If SignBitOnly is true, test for a known 0 sign bit rather than a standard ordered compare. More...
 
static ValueBuildSubAggregate (Value *From, Value *To, Type *IndexedType, SmallVectorImpl< unsigned > &Idxs, unsigned IdxSkip, Instruction *InsertBefore)
 
static ValueBuildSubAggregate (Value *From, ArrayRef< unsigned > idx_range, Instruction *InsertBefore)
 
static uint64_t GetStringLengthH (const Value *V, SmallPtrSetImpl< const PHINode * > &PHIs)
 If we can compute the length of the string pointed to by the specified pointer, return 'len+1'. More...
 
static bool isSameUnderlyingObjectInLoop (const PHINode *PN, const LoopInfo *LI)
 PN defines a loop-variant pointer to an object. More...
 
static bool isKnownNonNullFromDominatingCondition (const Value *V, const Instruction *CtxI, const DominatorTree *DT)
 
static OverflowResult computeOverflowForSignedAdd (const Value *LHS, const Value *RHS, const AddOperator *Add, const DataLayout &DL, AssumptionCache *AC, const Instruction *CxtI, const DominatorTree *DT)
 
static bool isKnownNonNaN (const Value *V, FastMathFlags FMF)
 
static bool isKnownNonZero (const Value *V)
 
static SelectPatternResult matchMinMax (CmpInst::Predicate Pred, Value *CmpLHS, Value *CmpRHS, Value *TrueVal, Value *FalseVal, Value *&LHS, Value *&RHS)
 Match non-obvious integer minimum and maximum sequences. More...
 
static SelectPatternResult matchSelectPattern (CmpInst::Predicate Pred, FastMathFlags FMF, Value *CmpLHS, Value *CmpRHS, Value *TrueVal, Value *FalseVal, Value *&LHS, Value *&RHS)
 
static ValuelookThroughCast (CmpInst *CmpI, Value *V1, Value *V2, Instruction::CastOps *CastOp)
 
static bool isTruePredicate (CmpInst::Predicate Pred, const Value *LHS, const Value *RHS, const DataLayout &DL, unsigned Depth, AssumptionCache *AC, const Instruction *CxtI, const DominatorTree *DT)
 Return true if "icmp Pred LHS RHS" is always true. More...
 
static Optional< boolisImpliedCondOperands (CmpInst::Predicate Pred, const Value *ALHS, const Value *ARHS, const Value *BLHS, const Value *BRHS, const DataLayout &DL, unsigned Depth, AssumptionCache *AC, const Instruction *CxtI, const DominatorTree *DT)
 Return true if "icmp Pred BLHS BRHS" is true whenever "icmp Pred ALHS ARHS" is true. More...
 
static bool isMatchingOps (const Value *ALHS, const Value *ARHS, const Value *BLHS, const Value *BRHS, bool &IsSwappedOps)
 Return true if the operands of the two compares match. More...
 
static Optional< boolisImpliedCondMatchingOperands (CmpInst::Predicate APred, const Value *ALHS, const Value *ARHS, CmpInst::Predicate BPred, const Value *BLHS, const Value *BRHS, bool IsSwappedOps)
 Return true if "icmp1 APred ALHS ARHS" implies "icmp2 BPred BLHS BRHS" is true. More...
 
static Optional< boolisImpliedCondMatchingImmOperands (CmpInst::Predicate APred, const Value *ALHS, const ConstantInt *C1, CmpInst::Predicate BPred, const Value *BLHS, const ConstantInt *C2)
 Return true if "icmp1 APred ALHS C1" implies "icmp2 BPred BLHS C2" is true. More...
 

Variables

const unsigned MaxDepth = 6
 
static cl::opt< unsignedDomConditionsMaxUses ("dom-conditions-max-uses", cl::Hidden, cl::init(20))
 
static cl::opt< boolDontImproveNonNegativePhiBits ("dont-improve-non-negative-phi-bits", cl::Hidden, cl::init(true))
 

Function Documentation

static Value* BuildSubAggregate ( Value From,
Value To,
Type IndexedType,
SmallVectorImpl< unsigned > &  Idxs,
unsigned  IdxSkip,
Instruction InsertBefore 
)
static
static Value* BuildSubAggregate ( Value From,
ArrayRef< unsigned idx_range,
Instruction InsertBefore 
)
static
static bool cannotBeOrderedLessThanZeroImpl ( const Value V,
const TargetLibraryInfo TLI,
bool  SignBitOnly,
unsigned  Depth 
)
static

If SignBitOnly is true, test for a known 0 sign bit rather than a standard ordered compare.

e.g. make -0.0 olt 0.0 be true because of the sign bit despite comparing equal.

Definition at line 2589 of file ValueTracking.cpp.

References llvm::Call, llvm::dyn_cast(), llvm::getIntrinsicForCallSite(), llvm::Operator::getOpcode(), llvm::User::getOperand(), I, LLVM_FALLTHROUGH, MaxDepth, llvm::maxnum(), llvm::minnum(), and llvm::MCID::Select.

Referenced by llvm::CannotBeOrderedLessThanZero(), and llvm::SignBitMustBeZero().

void computeKnownBits ( const Value V,
APInt KnownZero,
APInt KnownOne,
unsigned  Depth,
const Query Q 
)
static

Determine which bits of V are known to be either zero or one and return them in the KnownZero/KnownOne bit sets.

NOTE: we cannot consider 'undef' to be "IsZero" here. The problem is that we cannot optimize based on the assumption that it is zero without changing it to be an explicit zero. If we don't change it to zero, other code could optimized based on the contradictory assumption that it is non-zero. Because instcombine aggressively folds operations with undef args anyway, this won't lose us code quality.

This function is defined on values with integer type, values with pointer type, and vectors of integers. In the case where V is a vector, known zero, and known one values are the same width as the vector element, and the bit is set only if it is true for all of the elements in the vector.

Definition at line 1490 of file ValueTracking.cpp.

References assert(), C, llvm::APInt::clearAllBits(), llvm::computeKnownBits(), computeKnownBitsFromAssume(), computeKnownBitsFromOperator(), llvm::countTrailingZeros(), llvm::Constant::getAggregateElement(), llvm::APInt::getAllOnesValue(), llvm::APInt::getBitWidth(), llvm::APInt::getLowBitsSet(), llvm::Value::getPointerAlignment(), llvm::Type::getScalarSizeInBits(), llvm::Type::getScalarType(), llvm::Value::getType(), i, llvm::Type::isIntOrIntVectorTy(), llvm::Type::isPointerTy(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::match(), MaxDepth, and llvm::APInt::setAllBits().

static void computeKnownBitsAddSub ( bool  Add,
const Value Op0,
const Value Op1,
bool  NSW,
APInt KnownZero,
APInt KnownOne,
APInt KnownZero2,
APInt KnownOne2,
unsigned  Depth,
const Query Q 
)
static
static void computeKnownBitsFromAssume ( const Value V,
APInt KnownZero,
APInt KnownOne,
unsigned  Depth,
const Query Q 
)
static
static void computeKnownBitsFromOperator ( const Operator I,
APInt KnownZero,
APInt KnownOne,
unsigned  Depth,
const Query Q 
)
static

Definition at line 880 of file ValueTracking.cpp.

References llvm::APInt::abs(), llvm::MCID::Add, llvm::APIntOps::And(), llvm::APIntOps::ashr(), assert(), llvm::APInt::byteSwap(), llvm::Call, llvm::APInt::clearAllBits(), llvm::computeKnownBits(), computeKnownBitsAddSub(), llvm::computeKnownBitsFromRangeMetadata(), computeKnownBitsFromShiftOperator(), computeKnownBitsMul(), llvm::APInt::countLeadingOnes(), llvm::APInt::countLeadingZeros(), llvm::APInt::countPopulation(), llvm::APInt::countTrailingOnes(), llvm::countTrailingZeros(), llvm::Depth, DontImproveNonNegativePhiBits, llvm::dyn_cast(), llvm::SelectPatternResult::Flavor, llvm::gep_type_begin(), llvm::AllocaInst::getAlignment(), llvm::AllocaInst::getAllocatedType(), llvm::APInt::getAllOnesValue(), llvm::APInt::getBitWidth(), llvm::StructLayout::getElementOffset(), llvm::APInt::getHighBitsSet(), llvm::PHINode::getIncomingValue(), llvm::generic_gep_type_iterator< ItTy >::getIndexedType(), llvm::ExtractValueInst::getIndices(), llvm::APInt::getLowBitsSet(), llvm::PHINode::getNumIncomingValues(), llvm::ExtractValueInst::getNumIndices(), llvm::User::getNumOperands(), llvm::Operator::getOpcode(), llvm::User::getOperand(), llvm::Type::getScalarSizeInBits(), llvm::Type::getScalarType(), llvm::Constant::getSplatValue(), llvm::generic_gep_type_iterator< ItTy >::getStructTypeOrNull(), llvm::ConstantInt::getTrue(), llvm::Value::getType(), llvm::PHINode::hasConstantValue(), I, i, llvm::PHINode::incoming_values(), llvm::Type::isIntegerTy(), llvm::SelectPatternResult::isMinOrMax(), llvm::APInt::isNegative(), llvm::APInt::isNonNegative(), llvm::Type::isPointerTy(), llvm::APInt::isPowerOf2(), llvm::Type::isSized(), llvm::Type::isVectorTy(), llvm::Constant::isZeroValue(), L, LLVM_FALLTHROUGH, llvm::SPII::Load, llvm::Log2_32(), llvm::APIntOps::lshr(), llvm::PatternMatch::m_Add(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), llvm::matchSelectPattern(), MaxDepth, llvm::LLVMContext::MD_range, fuzzer::min(), Offset, llvm::APIntOps::Or(), P, llvm::MCID::Select, llvm::APInt::setBit(), llvm::SPF_SMAX, llvm::SPF_SMIN, llvm::SPF_UMAX, llvm::SPF_UMIN, llvm::APInt::trunc(), llvm::APIntOps::Xor(), Y, llvm::APInt::zext(), and llvm::APInt::zextOrTrunc().

Referenced by computeKnownBits().

static void computeKnownBitsFromShiftOperator ( const Operator I,
APInt KnownZero,
APInt KnownOne,
APInt KnownZero2,
APInt KnownOne2,
unsigned  Depth,
const Query Q,
function_ref< APInt(const APInt &, unsigned)>  KZF,
function_ref< APInt(const APInt &, unsigned)>  KOF 
)
static
static void computeKnownBitsMul ( const Value Op0,
const Value Op1,
bool  NSW,
APInt KnownZero,
APInt KnownOne,
APInt KnownZero2,
APInt KnownOne2,
unsigned  Depth,
const Query Q 
)
static
unsigned ComputeNumSignBits ( const Value V,
unsigned  Depth,
const Query Q 
)
static

Return the number of times the sign bit of the register is replicated into the other bits.

We know that at least 1 bit is always equal to the sign bit (itself), but other cases can give us information. For example, immediately after an "ashr X, 2", we know that the top 3 bits are all equal to each other, so we return 3. For vectors, return the number of sign bits for the vector element with the mininum number of known sign bits.

Definition at line 2084 of file ValueTracking.cpp.

References llvm::MCID::Add, llvm::APIntOps::And(), llvm::APInt::ceilLogBase2(), llvm::computeKnownBits(), llvm::ComputeNumSignBits(), computeNumSignBitsVectorConstant(), llvm::APInt::countLeadingOnes(), llvm::dyn_cast(), llvm::PHINode::getIncomingValue(), llvm::PHINode::getNumIncomingValues(), llvm::Operator::getOpcode(), llvm::User::getOperand(), llvm::Type::getScalarSizeInBits(), llvm::Type::getScalarType(), llvm::Value::getType(), llvm::APInt::getZExtValue(), i, llvm::APInt::isNegative(), llvm::APInt::isStrictlyPositive(), llvm::APInt::logBase2(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::match(), MaxDepth, fuzzer::min(), llvm::APIntOps::Or(), llvm::MCID::Select, and llvm::APIntOps::Xor().

Referenced by llvm::ComputeNumSignBits().

static unsigned computeNumSignBitsVectorConstant ( const Value V,
unsigned  TyBits 
)
static

For vector constants, loop over the elements and find the constant with the minimum number of sign bits.

Return 0 if the value is not a vector constant or if any element was not analyzed; otherwise, return the count for the element with the minimum number of sign bits.

Definition at line 2054 of file ValueTracking.cpp.

References llvm::APInt::countLeadingZeros(), llvm::dyn_cast(), i, llvm::APInt::isNegative(), and fuzzer::min().

Referenced by ComputeNumSignBits().

static OverflowResult computeOverflowForSignedAdd ( const Value LHS,
const Value RHS,
const AddOperator Add,
const DataLayout DL,
AssumptionCache AC,
const Instruction CxtI,
const DominatorTree DT 
)
static
void ComputeSignBit ( const Value V,
bool KnownZero,
bool KnownOne,
unsigned  Depth,
const Query Q 
)
static

Determine whether the sign bit is known to be zero or one.

Convenience wrapper around computeKnownBits.

Definition at line 1599 of file ValueTracking.cpp.

References llvm::computeKnownBits(), getBitWidth(), and llvm::Value::getType().

static unsigned getBitWidth ( Type Ty,
const DataLayout DL 
)
static
static uint64_t GetStringLengthH ( const Value V,
SmallPtrSetImpl< const PHINode * > &  PHIs 
)
static

If we can compute the length of the string pointed to by the specified pointer, return 'len+1'.

If we can't, return 0.

Definition at line 3052 of file ValueTracking.cpp.

References llvm::getConstantStringInfo(), llvm::SmallPtrSetImpl< PtrType >::insert(), SI, llvm::StringRef::size(), and llvm::Value::stripPointerCasts().

Referenced by llvm::GetStringLength().

static bool isAddOfNonZero ( const Value V1,
const Value V2,
const Query Q 
)
static

Return true if V2 == V1 + X, where X is known non-zero.

Definition at line 1992 of file ValueTracking.cpp.

References llvm::MCID::Add, llvm::dyn_cast(), llvm::BinaryOperator::getOpcode(), llvm::User::getOperand(), and llvm::isKnownNonZero().

Referenced by isKnownNonEqual().

static bool isAssumeLikeIntrinsic ( const Instruction I)
static

Definition at line 449 of file ValueTracking.cpp.

References F.

Referenced by llvm::isValidAssumeForContext().

static bool isEphemeralValueOf ( const Instruction I,
const Value E 
)
static
static bool isGEPKnownNonNull ( const GEPOperator GEP,
unsigned  Depth,
const Query Q 
)
static

Test whether a GEP's result is known to be non-null.

Uses properties inherent in a GEP to try to determine whether it is known to be non-null.

Currently this routine does not support vector GEPs.

Definition at line 1717 of file ValueTracking.cpp.

References assert(), llvm::Depth, llvm::gep_type_begin(), llvm::gep_type_end(), llvm::StructLayout::getElementOffset(), llvm::GEPOperator::getPointerAddressSpace(), llvm::GEPOperator::getPointerOperand(), llvm::Value::getType(), llvm::ConstantInt::getZExtValue(), llvm::GEPOperator::isInBounds(), llvm::isKnownNonZero(), llvm::Type::isPointerTy(), and MaxDepth.

Referenced by isKnownNonZero().

static Optional<bool> isImpliedCondMatchingImmOperands ( CmpInst::Predicate  APred,
const Value ALHS,
const ConstantInt C1,
CmpInst::Predicate  BPred,
const Value BLHS,
const ConstantInt C2 
)
static

Return true if "icmp1 APred ALHS C1" implies "icmp2 BPred BLHS C2" is true.

Return false if "icmp1 APred ALHS C1" implies "icmp2 BPred BLHS C2" is false. Otherwise, return None if we can't infer anything.

Definition at line 4328 of file ValueTracking.cpp.

References assert(), llvm::ConstantRange::difference(), llvm::ConstantInt::getValue(), llvm::ConstantRange::intersectWith(), llvm::ConstantRange::isEmptySet(), llvm::ConstantRange::makeAllowedICmpRegion(), llvm::ConstantRange::makeExactICmpRegion(), and llvm::None.

Referenced by llvm::isImpliedCondition().

static Optional<bool> isImpliedCondMatchingOperands ( CmpInst::Predicate  APred,
const Value ALHS,
const Value ARHS,
CmpInst::Predicate  BPred,
const Value BLHS,
const Value BRHS,
bool  IsSwappedOps 
)
static

Return true if "icmp1 APred ALHS ARHS" implies "icmp2 BPred BLHS BRHS" is true.

Return false if "icmp1 APred ALHS ARHS" implies "icmp2 BPred BLHS BRHS" is false. Otherwise, return None if we can't infer anything.

Definition at line 4304 of file ValueTracking.cpp.

References llvm::CmpInst::getSwappedPredicate(), llvm::CmpInst::isImpliedFalseByMatchingCmp(), llvm::CmpInst::isImpliedTrueByMatchingCmp(), llvm::None, and std::swap().

Referenced by llvm::isImpliedCondition().

static Optional<bool> isImpliedCondOperands ( CmpInst::Predicate  Pred,
const Value ALHS,
const Value ARHS,
const Value BLHS,
const Value BRHS,
const DataLayout DL,
unsigned  Depth,
AssumptionCache AC,
const Instruction CxtI,
const DominatorTree DT 
)
static

Return true if "icmp Pred BLHS BRHS" is true whenever "icmp Pred ALHS ARHS" is true.

Otherwise, return None.

Definition at line 4263 of file ValueTracking.cpp.

References llvm::CmpInst::ICMP_SLE, llvm::CmpInst::ICMP_SLT, llvm::CmpInst::ICMP_ULE, llvm::CmpInst::ICMP_ULT, isTruePredicate(), and llvm::None.

Referenced by llvm::isImpliedCondition().

static bool isKnownNonEqual ( const Value V1,
const Value V2,
const Query Q 
)
static

Return true if it is known that V1 != V2.

Definition at line 2007 of file ValueTracking.cpp.

References llvm::computeKnownBits(), llvm::Value::getType(), isAddOfNonZero(), llvm::Type::isVectorTy(), and llvm::NVPTX::PTXLdStInstCode::V2.

Referenced by llvm::isKnownNonEqual().

static bool isKnownNonNaN ( const Value V,
FastMathFlags  FMF 
)
static

Definition at line 3889 of file ValueTracking.cpp.

References C, and llvm::FastMathFlags::noNaNs().

Referenced by matchSelectPattern().

static bool isKnownNonNullFromDominatingCondition ( const Value V,
const Instruction CtxI,
const DominatorTree DT 
)
static
bool isKnownNonZero ( const Value V,
unsigned  Depth,
const Query Q 
)
static
static bool isKnownNonZero ( const Value V)
static

Definition at line 3898 of file ValueTracking.cpp.

References C.

bool isKnownToBeAPowerOfTwo ( const Value V,
bool  OrZero,
unsigned  Depth,
const Query Q 
)
static
static bool isMatchingOps ( const Value ALHS,
const Value ARHS,
const Value BLHS,
const Value BRHS,
bool IsSwappedOps 
)
static

Return true if the operands of the two compares match.

IsSwappedOps is true when the operands match, but are swapped.

Definition at line 4292 of file ValueTracking.cpp.

Referenced by llvm::isImpliedCondition().

static bool isSameUnderlyingObjectInLoop ( const PHINode PN,
const LoopInfo LI 
)
static

PN defines a loop-variant pointer to an object.

Check if the previous iteration of the loop was referring to the same object as PN.

Definition at line 3114 of file ValueTracking.cpp.

References llvm::dyn_cast(), llvm::PHINode::getIncomingValue(), llvm::LoopInfoBase< N, M >::getLoopFor(), llvm::PHINode::getNumIncomingValues(), llvm::Instruction::getParent(), llvm::Loop::isLoopInvariant(), L, and llvm::SPII::Load.

Referenced by llvm::GetUnderlyingObjects().

static bool isTruePredicate ( CmpInst::Predicate  Pred,
const Value LHS,
const Value RHS,
const DataLayout DL,
unsigned  Depth,
AssumptionCache AC,
const Instruction CxtI,
const DominatorTree DT 
)
static
static Value* lookThroughCast ( CmpInst CmpI,
Value V1,
Value V2,
Instruction::CastOps CastOp 
)
static
bool MaskedValueIsZero ( const Value V,
const APInt Mask,
unsigned  Depth,
const Query Q 
)
static

Return true if 'V & Mask' is known to be zero.

We use this predicate to simplify operations downstream. Mask is known to be zero for bits that V cannot have.

This function is defined on values with integer type, values with pointer type, and vectors of integers. In the case where V is a vector, the mask, known zero, and known one values are the same width as the vector element, and the bit is set only if it is true for all of the elements in the vector.

Definition at line 2043 of file ValueTracking.cpp.

References llvm::computeKnownBits(), llvm::APInt::getBitWidth(), and llvm::BitmaskEnumDetail::Mask().

Referenced by llvm::MaskedValueIsZero().

static SelectPatternResult matchMinMax ( CmpInst::Predicate  Pred,
Value CmpLHS,
Value CmpRHS,
Value TrueVal,
Value FalseVal,
Value *&  LHS,
Value *&  RHS 
)
static
static SelectPatternResult matchSelectPattern ( CmpInst::Predicate  Pred,
FastMathFlags  FMF,
Value CmpLHS,
Value CmpRHS,
Value TrueVal,
Value FalseVal,
Value *&  LHS,
Value *&  RHS 
)
static
static bool rangeMetadataExcludesValue ( const MDNode Ranges,
const APInt Value 
)
static

Does the 'Range' metadata (which must be a valid MD_range operand list) ensure that the value it's attached to is never Value? 'RangeType' is is the type of the value described by the range.

Definition at line 1776 of file ValueTracking.cpp.

References assert(), llvm::MDNode::getNumOperands(), llvm::MDNode::getOperand(), llvm::ConstantInt::getValue(), i, llvm::Lower, and llvm::Upper.

Referenced by isKnownNonZero().

static const Instruction* safeCxtI ( const Value V,
const Instruction CxtI 
)
static

Variable Documentation

cl::opt<unsigned> DomConditionsMaxUses("dom-conditions-max-uses", cl::Hidden, cl::init(20))
static
cl::opt<bool> DontImproveNonNegativePhiBits("dont-improve-non-negative-phi-bits", cl::Hidden, cl::init(true))
static
const unsigned MaxDepth = 6