LLVM 22.0.0git
llvm::KnownBits Struct Reference

#include "llvm/Support/KnownBits.h"

Public Member Functions

 KnownBits ()=default
 KnownBits (unsigned BitWidth)
 Create a known bits object of BitWidth bits initialized to unknown.
unsigned getBitWidth () const
 Get the bit width of this value.
bool hasConflict () const
 Returns true if there is conflicting information.
bool isConstant () const
 Returns true if we know the value of all bits.
const APIntgetConstant () const
 Returns the value when all bits have a known value.
bool isUnknown () const
 Returns true if we don't know any bits.
bool isSignUnknown () const
 Returns true if we don't know the sign bit.
void resetAll ()
 Resets the known state of all bits.
bool isZero () const
 Returns true if value is all zero.
bool isAllOnes () const
 Returns true if value is all one bits.
void setAllZero ()
 Make all bits known to be zero and discard any previous information.
void setAllOnes ()
 Make all bits known to be one and discard any previous information.
void setAllConflict ()
 Make all bits known to be both zero and one.
bool isNegative () const
 Returns true if this value is known to be negative.
bool isNonNegative () const
 Returns true if this value is known to be non-negative.
bool isNonZero () const
 Returns true if this value is known to be non-zero.
bool isStrictlyPositive () const
 Returns true if this value is known to be positive.
void makeNegative ()
 Make this value negative.
void makeNonNegative ()
 Make this value non-negative.
APInt getMinValue () const
 Return the minimal unsigned value possible given these KnownBits.
APInt getSignedMinValue () const
 Return the minimal signed value possible given these KnownBits.
APInt getMaxValue () const
 Return the maximal unsigned value possible given these KnownBits.
APInt getSignedMaxValue () const
 Return the maximal signed value possible given these KnownBits.
KnownBits trunc (unsigned BitWidth) const
 Return known bits for a truncation of the value we're tracking.
KnownBits anyext (unsigned BitWidth) const
 Return known bits for an "any" extension of the value we're tracking, where we don't know anything about the extended bits.
KnownBits zext (unsigned BitWidth) const
 Return known bits for a zero extension of the value we're tracking.
KnownBits sext (unsigned BitWidth) const
 Return known bits for a sign extension of the value we're tracking.
KnownBits anyextOrTrunc (unsigned BitWidth) const
 Return known bits for an "any" extension or truncation of the value we're tracking.
KnownBits zextOrTrunc (unsigned BitWidth) const
 Return known bits for a zero extension or truncation of the value we're tracking.
KnownBits sextOrTrunc (unsigned BitWidth) const
 Return known bits for a sign extension or truncation of the value we're tracking.
LLVM_ABI KnownBits sextInReg (unsigned SrcBitWidth) const
 Return known bits for a in-register sign extension of the value we're tracking.
void insertBits (const KnownBits &SubBits, unsigned BitPosition)
 Insert the bits from a smaller known bits starting at bitPosition.
KnownBits extractBits (unsigned NumBits, unsigned BitPosition) const
 Return a subset of the known bits from [bitPosition,bitPosition+numBits).
KnownBits concat (const KnownBits &Lo) const
 Concatenate the bits from Lo onto the bottom of *this.
LLVM_ABI KnownBits makeGE (const APInt &Val) const
 Return KnownBits based on this, but updated given that the underlying value is known to be greater than or equal to Val.
unsigned countMinTrailingZeros () const
 Returns the minimum number of trailing zero bits.
unsigned countMinTrailingOnes () const
 Returns the minimum number of trailing one bits.
unsigned countMinLeadingZeros () const
 Returns the minimum number of leading zero bits.
unsigned countMinLeadingOnes () const
 Returns the minimum number of leading one bits.
unsigned countMinSignBits () const
 Returns the number of times the sign bit is replicated into the other bits.
unsigned countMaxSignificantBits () const
 Returns the maximum number of bits needed to represent all possible signed values with these known bits.
unsigned countMaxTrailingZeros () const
 Returns the maximum number of trailing zero bits possible.
unsigned countMaxTrailingOnes () const
 Returns the maximum number of trailing one bits possible.
unsigned countMaxLeadingZeros () const
 Returns the maximum number of leading zero bits possible.
unsigned countMaxLeadingOnes () const
 Returns the maximum number of leading one bits possible.
unsigned countMinPopulation () const
 Returns the number of bits known to be one.
unsigned countMaxPopulation () const
 Returns the maximum number of bits that could be one.
unsigned countMaxActiveBits () const
 Returns the maximum number of bits needed to represent all possible unsigned values with these known bits.
KnownBits intersectWith (const KnownBits &RHS) const
 Returns KnownBits information that is known to be true for both this and RHS.
KnownBits unionWith (const KnownBits &RHS) const
 Returns KnownBits information that is known to be true for either this or RHS or both.
LLVM_ABI KnownBitsoperator&= (const KnownBits &RHS)
 Update known bits based on ANDing with RHS.
LLVM_ABI KnownBitsoperator|= (const KnownBits &RHS)
 Update known bits based on ORing with RHS.
LLVM_ABI KnownBitsoperator^= (const KnownBits &RHS)
 Update known bits based on XORing with RHS.
KnownBitsoperator<<= (unsigned ShAmt)
 Shift known bits left by ShAmt. Shift in bits are unknown.
KnownBitsoperator>>= (unsigned ShAmt)
 Shift known bits right by ShAmt. Shifted in bits are unknown.
LLVM_ABI KnownBits abs (bool IntMinIsPoison=false) const
 Compute known bits for the absolute value.
KnownBits byteSwap () const
KnownBits reverseBits () const
LLVM_ABI KnownBits blsi () const
 Compute known bits for X & -X, which has only the lowest bit set of X set.
LLVM_ABI KnownBits blsmsk () const
 Compute known bits for X ^ (X - 1), which has all bits up to and including the lowest set bit of X set.
bool operator== (const KnownBits &Other) const
bool operator!= (const KnownBits &Other) const
LLVM_ABI void print (raw_ostream &OS) const
LLVM_DUMP_METHOD void dump () const

Static Public Member Functions

static KnownBits makeConstant (const APInt &C)
 Create known bits from a known constant.
static bool haveNoCommonBitsSet (const KnownBits &LHS, const KnownBits &RHS)
 Return true if LHS and RHS have no common bits set.
static LLVM_ABI KnownBits computeForAddCarry (const KnownBits &LHS, const KnownBits &RHS, const KnownBits &Carry)
 Compute known bits resulting from adding LHS, RHS and a 1-bit Carry.
static LLVM_ABI KnownBits computeForAddSub (bool Add, bool NSW, bool NUW, const KnownBits &LHS, const KnownBits &RHS)
 Compute known bits resulting from adding LHS and RHS.
static LLVM_ABI KnownBits computeForSubBorrow (const KnownBits &LHS, KnownBits RHS, const KnownBits &Borrow)
 Compute known bits results from subtracting RHS from LHS with 1-bit Borrow.
static KnownBits add (const KnownBits &LHS, const KnownBits &RHS, bool NSW=false, bool NUW=false)
 Compute knownbits resulting from addition of LHS and RHS.
static KnownBits sub (const KnownBits &LHS, const KnownBits &RHS, bool NSW=false, bool NUW=false)
 Compute knownbits resulting from subtraction of LHS and RHS.
static LLVM_ABI KnownBits sadd_sat (const KnownBits &LHS, const KnownBits &RHS)
 Compute knownbits resulting from llvm.sadd.sat(LHS, RHS)
static LLVM_ABI KnownBits uadd_sat (const KnownBits &LHS, const KnownBits &RHS)
 Compute knownbits resulting from llvm.uadd.sat(LHS, RHS)
static LLVM_ABI KnownBits ssub_sat (const KnownBits &LHS, const KnownBits &RHS)
 Compute knownbits resulting from llvm.ssub.sat(LHS, RHS)
static LLVM_ABI KnownBits usub_sat (const KnownBits &LHS, const KnownBits &RHS)
 Compute knownbits resulting from llvm.usub.sat(LHS, RHS)
static LLVM_ABI KnownBits avgFloorS (const KnownBits &LHS, const KnownBits &RHS)
 Compute knownbits resulting from APIntOps::avgFloorS.
static LLVM_ABI KnownBits avgFloorU (const KnownBits &LHS, const KnownBits &RHS)
 Compute knownbits resulting from APIntOps::avgFloorU.
static LLVM_ABI KnownBits avgCeilS (const KnownBits &LHS, const KnownBits &RHS)
 Compute knownbits resulting from APIntOps::avgCeilS.
static LLVM_ABI KnownBits avgCeilU (const KnownBits &LHS, const KnownBits &RHS)
 Compute knownbits resulting from APIntOps::avgCeilU.
static LLVM_ABI KnownBits mul (const KnownBits &LHS, const KnownBits &RHS, bool NoUndefSelfMultiply=false)
 Compute known bits resulting from multiplying LHS and RHS.
static LLVM_ABI KnownBits mulhs (const KnownBits &LHS, const KnownBits &RHS)
 Compute known bits from sign-extended multiply-hi.
static LLVM_ABI KnownBits mulhu (const KnownBits &LHS, const KnownBits &RHS)
 Compute known bits from zero-extended multiply-hi.
static LLVM_ABI KnownBits sdiv (const KnownBits &LHS, const KnownBits &RHS, bool Exact=false)
 Compute known bits for sdiv(LHS, RHS).
static LLVM_ABI KnownBits udiv (const KnownBits &LHS, const KnownBits &RHS, bool Exact=false)
 Compute known bits for udiv(LHS, RHS).
static LLVM_ABI KnownBits urem (const KnownBits &LHS, const KnownBits &RHS)
 Compute known bits for urem(LHS, RHS).
static LLVM_ABI KnownBits srem (const KnownBits &LHS, const KnownBits &RHS)
 Compute known bits for srem(LHS, RHS).
static LLVM_ABI KnownBits umax (const KnownBits &LHS, const KnownBits &RHS)
 Compute known bits for umax(LHS, RHS).
static LLVM_ABI KnownBits umin (const KnownBits &LHS, const KnownBits &RHS)
 Compute known bits for umin(LHS, RHS).
static LLVM_ABI KnownBits smax (const KnownBits &LHS, const KnownBits &RHS)
 Compute known bits for smax(LHS, RHS).
static LLVM_ABI KnownBits smin (const KnownBits &LHS, const KnownBits &RHS)
 Compute known bits for smin(LHS, RHS).
static LLVM_ABI KnownBits abdu (const KnownBits &LHS, const KnownBits &RHS)
 Compute known bits for abdu(LHS, RHS).
static LLVM_ABI KnownBits abds (KnownBits LHS, KnownBits RHS)
 Compute known bits for abds(LHS, RHS).
static LLVM_ABI KnownBits shl (const KnownBits &LHS, const KnownBits &RHS, bool NUW=false, bool NSW=false, bool ShAmtNonZero=false)
 Compute known bits for shl(LHS, RHS).
static LLVM_ABI KnownBits lshr (const KnownBits &LHS, const KnownBits &RHS, bool ShAmtNonZero=false, bool Exact=false)
 Compute known bits for lshr(LHS, RHS).
static LLVM_ABI KnownBits ashr (const KnownBits &LHS, const KnownBits &RHS, bool ShAmtNonZero=false, bool Exact=false)
 Compute known bits for ashr(LHS, RHS).
static LLVM_ABI std::optional< booleq (const KnownBits &LHS, const KnownBits &RHS)
 Determine if these known bits always give the same ICMP_EQ result.
static LLVM_ABI std::optional< boolne (const KnownBits &LHS, const KnownBits &RHS)
 Determine if these known bits always give the same ICMP_NE result.
static LLVM_ABI std::optional< boolugt (const KnownBits &LHS, const KnownBits &RHS)
 Determine if these known bits always give the same ICMP_UGT result.
static LLVM_ABI std::optional< booluge (const KnownBits &LHS, const KnownBits &RHS)
 Determine if these known bits always give the same ICMP_UGE result.
static LLVM_ABI std::optional< boolult (const KnownBits &LHS, const KnownBits &RHS)
 Determine if these known bits always give the same ICMP_ULT result.
static LLVM_ABI std::optional< boolule (const KnownBits &LHS, const KnownBits &RHS)
 Determine if these known bits always give the same ICMP_ULE result.
static LLVM_ABI std::optional< boolsgt (const KnownBits &LHS, const KnownBits &RHS)
 Determine if these known bits always give the same ICMP_SGT result.
static LLVM_ABI std::optional< boolsge (const KnownBits &LHS, const KnownBits &RHS)
 Determine if these known bits always give the same ICMP_SGE result.
static LLVM_ABI std::optional< boolslt (const KnownBits &LHS, const KnownBits &RHS)
 Determine if these known bits always give the same ICMP_SLT result.
static LLVM_ABI std::optional< boolsle (const KnownBits &LHS, const KnownBits &RHS)
 Determine if these known bits always give the same ICMP_SLE result.

Public Attributes

APInt Zero
APInt One

Detailed Description

Definition at line 24 of file KnownBits.h.

Constructor & Destructor Documentation

◆ KnownBits() [1/2]

◆ KnownBits() [2/2]

llvm::KnownBits::KnownBits ( unsigned BitWidth)
inline

Create a known bits object of BitWidth bits initialized to unknown.

Definition at line 41 of file KnownBits.h.

References llvm::BitWidth, One, and Zero.

Member Function Documentation

◆ abds()

KnownBits KnownBits::abds ( KnownBits LHS,
KnownBits RHS )
static

Compute known bits for abds(LHS, RHS).

Definition at line 247 of file KnownBits.cpp.

References computeForAddSub(), and intersectWith().

Referenced by llvm::SelectionDAG::computeKnownBits().

◆ abdu()

KnownBits KnownBits::abdu ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute known bits for abdu(LHS, RHS).

Definition at line 228 of file KnownBits.cpp.

References computeForAddSub(), and intersectWith().

Referenced by llvm::SelectionDAG::computeKnownBits(), and computeKnownBitsForPSADBW().

◆ abs()

◆ add()

◆ anyext()

KnownBits llvm::KnownBits::anyext ( unsigned BitWidth) const
inline

Return known bits for an "any" extension of the value we're tracking, where we don't know anything about the extended bits.

Definition at line 167 of file KnownBits.h.

References llvm::BitWidth, KnownBits(), One, and Zero.

Referenced by anyextOrTrunc(), llvm::SelectionDAG::computeKnownBits(), computeKnownBitsFromCond(), computeKnownBitsFromICmpCond(), llvm::GISelValueTracking::computeKnownBitsImpl(), llvm::FunctionLoweringInfo::GetLiveOutRegInfo(), and llvm::TargetLowering::SimplifyDemandedBits().

◆ anyextOrTrunc()

◆ ashr()

◆ avgCeilS()

KnownBits KnownBits::avgCeilS ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute knownbits resulting from APIntOps::avgCeilS.

Definition at line 792 of file KnownBits.cpp.

References avgCeilU().

Referenced by llvm::SelectionDAG::computeKnownBits().

◆ avgCeilU()

KnownBits KnownBits::avgCeilU ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute knownbits resulting from APIntOps::avgCeilU.

Definition at line 796 of file KnownBits.cpp.

References avgComputeU().

Referenced by avgCeilS(), and llvm::SelectionDAG::computeKnownBits().

◆ avgFloorS()

KnownBits KnownBits::avgFloorS ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute knownbits resulting from APIntOps::avgFloorS.

Definition at line 784 of file KnownBits.cpp.

References avgFloorU().

Referenced by llvm::SelectionDAG::computeKnownBits().

◆ avgFloorU()

KnownBits KnownBits::avgFloorU ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute knownbits resulting from APIntOps::avgFloorU.

Definition at line 788 of file KnownBits.cpp.

References avgComputeU().

Referenced by avgFloorS(), and llvm::SelectionDAG::computeKnownBits().

◆ blsi()

KnownBits KnownBits::blsi ( ) const

Compute known bits for X & -X, which has only the lowest bit set of X set.

The name comes from the X86 BMI instruction

Definition at line 1124 of file KnownBits.cpp.

References llvm::BitWidth, countMaxTrailingZeros(), countMinTrailingZeros(), getBitWidth(), One, llvm::APInt::setBit(), llvm::APInt::setBitsFrom(), and Zero.

Referenced by getKnownBitsFromAndXorOr().

◆ blsmsk()

KnownBits KnownBits::blsmsk ( ) const

Compute known bits for X ^ (X - 1), which has all bits up to and including the lowest set bit of X set.

The name comes from the X86 BMI instruction.

Definition at line 1135 of file KnownBits.cpp.

References llvm::BitWidth, countMaxTrailingZeros(), countMinTrailingZeros(), getBitWidth(), One, llvm::APInt::setBitsFrom(), llvm::APInt::setLowBits(), and Zero.

Referenced by getKnownBitsFromAndXorOr().

◆ byteSwap()

◆ computeForAddCarry()

KnownBits KnownBits::computeForAddCarry ( const KnownBits & LHS,
const KnownBits & RHS,
const KnownBits & Carry )
static

Compute known bits resulting from adding LHS, RHS and a 1-bit Carry.

Definition at line 53 of file KnownBits.cpp.

References assert(), getBitWidth(), llvm::APInt::getBoolValue(), One, and Zero.

Referenced by computeForAddSub(), and llvm::SelectionDAG::computeKnownBits().

◆ computeForAddSub()

◆ computeForSubBorrow()

KnownBits KnownBits::computeForSubBorrow ( const KnownBits & LHS,
KnownBits RHS,
const KnownBits & Borrow )
static

Compute known bits results from subtracting RHS from LHS with 1-bit Borrow.

Definition at line 146 of file KnownBits.cpp.

References assert(), getBitWidth(), llvm::APInt::getBoolValue(), One, std::swap(), and Zero.

Referenced by llvm::SelectionDAG::computeKnownBits().

◆ concat()

KnownBits llvm::KnownBits::concat ( const KnownBits & Lo) const
inline

Concatenate the bits from Lo onto the bottom of *this.

This is equivalent to: (this->zext(NewWidth) << Lo.getBitWidth()) | Lo.zext(NewWidth)

Definition at line 233 of file KnownBits.h.

References KnownBits(), llvm::Lo, One, and Zero.

Referenced by llvm::SelectionDAG::computeKnownBits(), computeKnownBitsForPRMT(), and llvm::TargetLowering::SimplifyDemandedBits().

◆ countMaxActiveBits()

unsigned llvm::KnownBits::countMaxActiveBits ( ) const
inline

Returns the maximum number of bits needed to represent all possible unsigned values with these known bits.

This is the inverse of the minimum number of leading zeros.

Definition at line 296 of file KnownBits.h.

References countMinLeadingZeros(), and getBitWidth().

Referenced by combinePMULH(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), llvm::RISCVTargetLowering::computeKnownBitsForTargetNode(), detectExtMul(), foldSwitchToSelect(), getPack(), narrowIndex(), llvm::AMDGPUTargetLowering::numBitsUnsigned(), performSIGN_EXTEND_INREGCombine(), simplifyAndInst(), and simplifyLShrInst().

◆ countMaxLeadingOnes()

unsigned llvm::KnownBits::countMaxLeadingOnes ( ) const
inline

Returns the maximum number of leading one bits possible.

Definition at line 283 of file KnownBits.h.

References Zero.

◆ countMaxLeadingZeros()

unsigned llvm::KnownBits::countMaxLeadingZeros ( ) const
inline

◆ countMaxPopulation()

◆ countMaxSignificantBits()

unsigned llvm::KnownBits::countMaxSignificantBits ( ) const
inline

Returns the maximum number of bits needed to represent all possible signed values with these known bits.

This is the inverse of the minimum number of known sign bits. Examples for bitwidth 5: 110?? --> 4 0000? --> 2

Definition at line 269 of file KnownBits.h.

References countMinSignBits(), and getBitWidth().

Referenced by llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode().

◆ countMaxTrailingOnes()

unsigned llvm::KnownBits::countMaxTrailingOnes ( ) const
inline

Returns the maximum number of trailing one bits possible.

Definition at line 277 of file KnownBits.h.

References Zero.

◆ countMaxTrailingZeros()

◆ countMinLeadingOnes()

unsigned llvm::KnownBits::countMinLeadingOnes ( ) const
inline

Returns the minimum number of leading one bits.

Definition at line 251 of file KnownBits.h.

References One.

Referenced by computeKnownBitsFromOperator(), countMinSignBits(), getMinUselessShift(), llvm::GCNTTIImpl::rewriteIntrinsicWithAddressSpace(), and llvm::InstCombinerImpl::visitSwitchInst().

◆ countMinLeadingZeros()

◆ countMinPopulation()

unsigned llvm::KnownBits::countMinPopulation ( ) const
inline

Returns the number of bits known to be one.

Definition at line 286 of file KnownBits.h.

References One.

Referenced by abs(), foldCtpop(), foldCtpopPow2Test(), llvm::InstCombinerImpl::foldICmpWithZero(), llvm::isKnownToBeAPowerOfTwo(), and llvm::TargetLowering::SimplifySetCC().

◆ countMinSignBits()

unsigned llvm::KnownBits::countMinSignBits ( ) const
inline

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

Definition at line 255 of file KnownBits.h.

References countMinLeadingOnes(), countMinLeadingZeros(), isNegative(), and isNonNegative().

Referenced by llvm::SelectionDAG::ComputeNumSignBits(), ComputeNumSignBitsImpl(), countMaxSignificantBits(), setShiftFlags(), and llvm::TargetLowering::SimplifyDemandedBits().

◆ countMinTrailingOnes()

unsigned llvm::KnownBits::countMinTrailingOnes ( ) const
inline

Returns the minimum number of trailing one bits.

Definition at line 245 of file KnownBits.h.

References One.

Referenced by getKnownBitsFromAndXorOr().

◆ countMinTrailingZeros()

◆ dump()

LLVM_DUMP_METHOD void KnownBits::dump ( ) const

Definition at line 1161 of file KnownBits.cpp.

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

◆ eq()

std::optional< bool > KnownBits::eq ( const KnownBits & LHS,
const KnownBits & RHS )
static

Determine if these known bits always give the same ICMP_EQ result.

Definition at line 484 of file KnownBits.cpp.

Referenced by binaryOpKnownBitsMapHelper(), llvm::ICmpInst::compare(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), computeKnownFPClass(), and ne().

◆ extractBits()

KnownBits llvm::KnownBits::extractBits ( unsigned NumBits,
unsigned BitPosition ) const
inline

◆ getBitWidth()

unsigned llvm::KnownBits::getBitWidth ( ) const
inline

Get the bit width of this value.

Definition at line 44 of file KnownBits.h.

References assert(), One, and Zero.

Referenced by abs(), llvm::adjustKnownBitsForSelectArm(), anyextOrTrunc(), blsi(), blsmsk(), combineFMulcFCMulc(), computeForAddCarry(), computeForSubBorrow(), computeKnownBits(), llvm::SelectionDAG::computeKnownBits(), computeKnownBitsForLoadV(), computeKnownBitsForPRMT(), llvm::AArch64TargetLowering::computeKnownBitsForTargetNode(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), llvm::ARMTargetLowering::computeKnownBitsForTargetNode(), llvm::LanaiTargetLowering::computeKnownBitsForTargetNode(), llvm::RISCVTargetLowering::computeKnownBitsForTargetNode(), llvm::SystemZTargetLowering::computeKnownBitsForTargetNode(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromCmp(), computeKnownBitsFromCond(), llvm::computeKnownBitsFromContext(), computeKnownBitsFromICmpCond(), computeKnownBitsFromOperator(), llvm::computeKnownBitsFromRangeMetadata(), computeKnownBitsFromShiftOperator(), llvm::GISelValueTracking::computeKnownBitsImpl(), computeKnownBitsMul(), countMaxActiveBits(), countMaxPopulation(), countMaxSignificantBits(), eliminateDeadSwitchCases(), foldShiftIntoShiftInAnotherHandOfAndInICmp(), llvm::ConstantRange::fromKnownBits(), getKnownBitsFromAndXorOr(), llvm::FunctionLoweringInfo::GetLiveOutRegInfo(), getMinUselessShift(), llvm::getOrEnforceKnownAlignment(), inferAlignment(), isConstant(), llvm::SelectionDAG::isKnownNeverZero(), isNonZeroShift(), isSignificantBitCheckWellFormed(), LowerCTPOP(), makeGE(), print(), setShiftFlags(), sextInReg(), sextOrTrunc(), llvm::TargetLowering::SimplifyDemandedBits(), llvm::InstCombinerImpl::SimplifyDemandedInstructionBits(), llvm::InstCombinerImpl::SimplifyDemandedUseBits(), simplifyDivRem(), simplifyShift(), smin(), tryBitfieldInsertOpFromOr(), llvm::InstCombinerImpl::visitCallInst(), llvm::InstCombinerImpl::visitSwitchInst(), zext(), and zextOrTrunc().

◆ getConstant()

const APInt & llvm::KnownBits::getConstant ( ) const
inline

Returns the value when all bits have a known value.

This just returns One with a protective assertion.

Definition at line 60 of file KnownBits.h.

References assert(), isConstant(), and One.

Referenced by combineFMulcFCMulc(), combineMul(), llvm::InstCombinerImpl::foldICmpUsingKnownBits(), LowerCTPOP(), LowerShift(), LowerVectorAllEqual(), llvm::X86TargetLowering::SimplifyDemandedBitsForTargetNode(), llvm::GCNTTIImpl::simplifyDemandedLaneMaskArg(), and tryFoldHelper().

◆ getMaxValue()

◆ getMinValue()

◆ getSignedMaxValue()

APInt llvm::KnownBits::getSignedMaxValue ( ) const
inline

Return the maximal signed value possible given these KnownBits.

Definition at line 151 of file KnownBits.h.

References One, and Zero.

Referenced by llvm::InstCombinerImpl::foldICmpUsingKnownBits().

◆ getSignedMinValue()

APInt llvm::KnownBits::getSignedMinValue ( ) const
inline

Return the minimal signed value possible given these KnownBits.

Definition at line 135 of file KnownBits.h.

References One, llvm::APInt::setSignBit(), and Zero.

Referenced by llvm::InstCombinerImpl::foldICmpUsingKnownBits(), and isSafeSignedCMN().

◆ hasConflict()

bool llvm::KnownBits::hasConflict ( ) const
inline

◆ haveNoCommonBitsSet()

bool llvm::KnownBits::haveNoCommonBitsSet ( const KnownBits & LHS,
const KnownBits & RHS )
inlinestatic

Return true if LHS and RHS have no common bits set.

Definition at line 326 of file KnownBits.h.

References LHS, and RHS.

Referenced by llvm::haveNoCommonBitsSet(), and llvm::SelectionDAG::haveNoCommonBitsSet().

◆ insertBits()

void llvm::KnownBits::insertBits ( const KnownBits & SubBits,
unsigned BitPosition )
inline

Insert the bits from a smaller known bits starting at bitPosition.

Definition at line 219 of file KnownBits.h.

References One, and Zero.

Referenced by llvm::SelectionDAG::computeKnownBits(), computeKnownBitsForPRMT(), computeKnownBitsFromOperator(), and llvm::GISelValueTracking::computeKnownBitsImpl().

◆ intersectWith()

◆ isAllOnes()

bool llvm::KnownBits::isAllOnes ( ) const
inline

Returns true if value is all one bits.

Definition at line 83 of file KnownBits.h.

References One.

Referenced by isTruncateOf(), matchBinaryShuffle(), and llvm::InstCombinerImpl::visitCallInst().

◆ isConstant()

◆ isNegative()

◆ isNonNegative()

◆ isNonZero()

◆ isSignUnknown()

bool llvm::KnownBits::isSignUnknown ( ) const
inline

Returns true if we don't know the sign bit.

Definition at line 69 of file KnownBits.h.

References One, and Zero.

Referenced by llvm::TargetLowering::SimplifyDemandedBits().

◆ isStrictlyPositive()

bool llvm::KnownBits::isStrictlyPositive ( ) const
inline

Returns true if this value is known to be positive.

Definition at line 114 of file KnownBits.h.

References One, and Zero.

Referenced by llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), llvm::InstCombinerImpl::foldICmpBinOp(), and llvm::SelectionDAG::isKnownNeverZero().

◆ isUnknown()

◆ isZero()

◆ lshr()

◆ makeConstant()

◆ makeGE()

KnownBits KnownBits::makeGE ( const APInt & Val) const

Return KnownBits based on this, but updated given that the underlying value is known to be greater than or equal to Val.

Definition at line 175 of file KnownBits.cpp.

References llvm::APInt::clearLowBits(), llvm::countl_one(), getBitWidth(), KnownBits(), N, One, and Zero.

◆ makeNegative()

void llvm::KnownBits::makeNegative ( )
inline

◆ makeNonNegative()

◆ mul()

◆ mulhs()

KnownBits KnownBits::mulhs ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute known bits from sign-extended multiply-hi.

Definition at line 905 of file KnownBits.cpp.

References assert(), llvm::BitWidth, extractBits(), and mul().

Referenced by llvm::SelectionDAG::computeKnownBits(), and computeKnownBitsFromOperator().

◆ mulhu()

KnownBits KnownBits::mulhu ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute known bits from zero-extended multiply-hi.

Definition at line 913 of file KnownBits.cpp.

References assert(), llvm::BitWidth, extractBits(), and mul().

Referenced by llvm::SelectionDAG::computeKnownBits(), computeKnownBitsFromOperator(), and llvm::X86TargetLowering::SimplifyDemandedBitsForTargetNode().

◆ ne()

std::optional< bool > KnownBits::ne ( const KnownBits & LHS,
const KnownBits & RHS )
static

Determine if these known bits always give the same ICMP_NE result.

Definition at line 492 of file KnownBits.cpp.

References eq().

Referenced by binaryOpKnownBitsMapHelper(), llvm::ICmpInst::compare(), and llvm::SelectionDAG::isKnownNeverZero().

◆ operator!=()

bool llvm::KnownBits::operator!= ( const KnownBits & Other) const
inline

Definition at line 534 of file KnownBits.h.

References llvm::Other.

◆ operator&=()

KnownBits & KnownBits::operator&= ( const KnownBits & RHS)

Update known bits based on ANDing with RHS.

Definition at line 1099 of file KnownBits.cpp.

References One, and Zero.

◆ operator<<=()

KnownBits & llvm::KnownBits::operator<<= ( unsigned ShAmt)
inline

Shift known bits left by ShAmt. Shift in bits are unknown.

Definition at line 498 of file KnownBits.h.

References One, and Zero.

◆ operator==()

bool llvm::KnownBits::operator== ( const KnownBits & Other) const
inline

Definition at line 530 of file KnownBits.h.

References One, llvm::Other, and Zero.

◆ operator>>=()

KnownBits & llvm::KnownBits::operator>>= ( unsigned ShAmt)
inline

Shift known bits right by ShAmt. Shifted in bits are unknown.

Definition at line 505 of file KnownBits.h.

References One, and Zero.

◆ operator^=()

KnownBits & KnownBits::operator^= ( const KnownBits & RHS)

Update known bits based on XORing with RHS.

Definition at line 1115 of file KnownBits.cpp.

References One, and Zero.

◆ operator|=()

KnownBits & KnownBits::operator|= ( const KnownBits & RHS)

Update known bits based on ORing with RHS.

Definition at line 1107 of file KnownBits.cpp.

References One, and Zero.

◆ print()

void KnownBits::print ( raw_ostream & OS) const

Definition at line 1145 of file KnownBits.cpp.

References llvm::BitWidth, getBitWidth(), I, N, One, and Zero.

Referenced by dump(), and llvm::operator<<().

◆ resetAll()

◆ reverseBits()

◆ sadd_sat()

KnownBits KnownBits::sadd_sat ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute knownbits resulting from llvm.sadd.sat(LHS, RHS)

Definition at line 761 of file KnownBits.cpp.

References computeForSatAddSub().

Referenced by computeKnownBitsForPMADDUBSW(), and computeKnownBitsFromOperator().

◆ sdiv()

◆ setAllConflict()

void llvm::KnownBits::setAllConflict ( )
inline

Make all bits known to be both zero and one.

Useful before a loop that calls intersectWith.

Definition at line 99 of file KnownBits.h.

References One, and Zero.

Referenced by ashr(), computeKnownBits(), llvm::SelectionDAG::computeKnownBits(), computeKnownBitsFromOperator(), llvm::computeKnownBitsFromRangeMetadata(), lshr(), shl(), and llvm::TargetLowering::SimplifyDemandedBits().

◆ setAllOnes()

void llvm::KnownBits::setAllOnes ( )
inline

Make all bits known to be one and discard any previous information.

Definition at line 92 of file KnownBits.h.

References One, and Zero.

Referenced by llvm::X86TargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromCond(), and llvm::computeKnownBitsFromContext().

◆ setAllZero()

◆ sext()

◆ sextInReg()

KnownBits KnownBits::sextInReg ( unsigned SrcBitWidth) const

Return known bits for a in-register sign extension of the value we're tracking.

Definition at line 158 of file KnownBits.cpp.

References assert(), llvm::BitWidth, getBitWidth(), One, and Zero.

Referenced by llvm::SelectionDAG::computeKnownBits(), and llvm::GISelValueTracking::computeKnownBitsImpl().

◆ sextOrTrunc()

KnownBits llvm::KnownBits::sextOrTrunc ( unsigned BitWidth) const
inline

Return known bits for a sign extension or truncation of the value we're tracking.

Definition at line 206 of file KnownBits.h.

References llvm::BitWidth, getBitWidth(), sext(), and trunc().

Referenced by computeKnownBitsFromOperator().

◆ sge()

std::optional< bool > KnownBits::sge ( const KnownBits & LHS,
const KnownBits & RHS )
static

Determine if these known bits always give the same ICMP_SGE result.

Definition at line 532 of file KnownBits.cpp.

References sgt().

Referenced by binaryOpKnownBitsMapHelper(), llvm::ICmpInst::compare(), llvm::TargetLowering::SimplifyDemandedBits(), and sle().

◆ sgt()

std::optional< bool > KnownBits::sgt ( const KnownBits & LHS,
const KnownBits & RHS )
static

◆ shl()

◆ sle()

std::optional< bool > KnownBits::sle ( const KnownBits & LHS,
const KnownBits & RHS )
static

Determine if these known bits always give the same ICMP_SLE result.

Definition at line 542 of file KnownBits.cpp.

References sge().

Referenced by binaryOpKnownBitsMapHelper(), llvm::ICmpInst::compare(), and llvm::TargetLowering::SimplifyDemandedBits().

◆ slt()

std::optional< bool > KnownBits::slt ( const KnownBits & LHS,
const KnownBits & RHS )
static

Determine if these known bits always give the same ICMP_SLT result.

Definition at line 538 of file KnownBits.cpp.

References sgt().

Referenced by binaryOpKnownBitsMapHelper(), llvm::ICmpInst::compare(), and llvm::TargetLowering::SimplifyDemandedBits().

◆ smax()

KnownBits KnownBits::smax ( const KnownBits & LHS,
const KnownBits & RHS )
static

◆ smin()

KnownBits KnownBits::smin ( const KnownBits & LHS,
const KnownBits & RHS )
static

◆ srem()

◆ ssub_sat()

KnownBits KnownBits::ssub_sat ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute knownbits resulting from llvm.ssub.sat(LHS, RHS)

Definition at line 764 of file KnownBits.cpp.

References computeForSatAddSub().

Referenced by computeKnownBitsFromOperator().

◆ sub()

KnownBits llvm::KnownBits::sub ( const KnownBits & LHS,
const KnownBits & RHS,
bool NSW = false,
bool NUW = false )
inlinestatic

◆ trunc()

◆ uadd_sat()

KnownBits KnownBits::uadd_sat ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute knownbits resulting from llvm.uadd.sat(LHS, RHS)

Definition at line 767 of file KnownBits.cpp.

References computeForSatAddSub().

Referenced by computeKnownBitsFromOperator().

◆ udiv()

◆ uge()

std::optional< bool > KnownBits::uge ( const KnownBits & LHS,
const KnownBits & RHS )
static

Determine if these known bits always give the same ICMP_UGE result.

Definition at line 508 of file KnownBits.cpp.

References ugt().

Referenced by llvm::ICmpInst::compare(), isKnownNonZeroFromOperator(), llvm::TargetLowering::SimplifyDemandedBits(), and ule().

◆ ugt()

std::optional< bool > KnownBits::ugt ( const KnownBits & LHS,
const KnownBits & RHS )
static

Determine if these known bits always give the same ICMP_UGT result.

Definition at line 498 of file KnownBits.cpp.

Referenced by llvm::ICmpInst::compare(), llvm::TargetLowering::SimplifyDemandedBits(), uge(), and ult().

◆ ule()

std::optional< bool > KnownBits::ule ( const KnownBits & LHS,
const KnownBits & RHS )
static

Determine if these known bits always give the same ICMP_ULE result.

Definition at line 518 of file KnownBits.cpp.

References uge().

Referenced by llvm::ICmpInst::compare(), and llvm::TargetLowering::SimplifyDemandedBits().

◆ ult()

std::optional< bool > KnownBits::ult ( const KnownBits & LHS,
const KnownBits & RHS )
static

Determine if these known bits always give the same ICMP_ULT result.

Definition at line 514 of file KnownBits.cpp.

References ugt().

Referenced by llvm::ICmpInst::compare(), and llvm::TargetLowering::SimplifyDemandedBits().

◆ umax()

◆ umin()

KnownBits KnownBits::umin ( const KnownBits & LHS,
const KnownBits & RHS )
static

◆ unionWith()

KnownBits llvm::KnownBits::unionWith ( const KnownBits & RHS) const
inline

Returns KnownBits information that is known to be true for either this or RHS or both.

This can be used to combine different sources of information about the known bits of a single value, e.g. information about the low bits and the high bits of the result of a multiplication.

Definition at line 321 of file KnownBits.h.

References KnownBits(), One, RHS, and Zero.

Referenced by llvm::adjustKnownBitsForSelectArm(), llvm::SelectionDAG::computeKnownBits(), computeKnownBitsFromCmp(), computeKnownBitsFromCond(), computeKnownBitsFromICmpCond(), computeKnownBitsFromOperator(), llvm::TargetLowering::SimplifyDemandedBits(), llvm::InstCombinerImpl::SimplifyDemandedUseBits(), and unionWithMinMaxIntrinsicClamp().

◆ urem()

KnownBits KnownBits::urem ( const KnownBits & LHS,
const KnownBits & RHS )
static

◆ usub_sat()

KnownBits KnownBits::usub_sat ( const KnownBits & LHS,
const KnownBits & RHS )
static

Compute knownbits resulting from llvm.usub.sat(LHS, RHS)

Definition at line 770 of file KnownBits.cpp.

References computeForSatAddSub().

Referenced by llvm::SelectionDAG::computeKnownBits(), and computeKnownBitsFromOperator().

◆ zext()

◆ zextOrTrunc()

Member Data Documentation

◆ One

APInt llvm::KnownBits::One

Definition at line 26 of file KnownBits.h.

Referenced by abs(), llvm::FunctionLoweringInfo::AddLiveOutRegInfo(), anyext(), ashr(), llvm::ConstantRange::binaryXor(), blsi(), blsmsk(), byteSwap(), llvm::SelectionDAGISel::CheckOrMask(), combineSetCC(), computeForAddCarry(), computeForAddCarry(), computeForAddSub(), computeForSatAddSub(), computeForSubBorrow(), computeKnownBits(), llvm::SelectionDAG::computeKnownBits(), llvm::SITargetLowering::computeKnownBitsForTargetInstr(), llvm::AArch64TargetLowering::computeKnownBitsForTargetNode(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), llvm::ARMTargetLowering::computeKnownBitsForTargetNode(), llvm::RISCVTargetLowering::computeKnownBitsForTargetNode(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromCmp(), llvm::computeKnownBitsFromContext(), computeKnownBitsFromOperator(), llvm::computeKnownBitsFromRangeMetadata(), llvm::GISelValueTracking::computeKnownBitsImpl(), llvm::GISelValueTracking::computeNumSignBits(), llvm::FunctionLoweringInfo::ComputePHILiveOutRegInfo(), concat(), countMaxLeadingZeros(), countMaxTrailingZeros(), countMinLeadingOnes(), countMinPopulation(), countMinTrailingOnes(), llvm::DemandedBits::determineLiveOperandBitsSub(), divComputeLowBit(), dumpResult(), eliminateDeadSwitchCases(), extractBits(), foldCtpopPow2Test(), foldCttzCtlz(), llvm::InstCombinerImpl::foldICmpBinOp(), llvm::InstCombinerImpl::foldICmpTruncConstant(), llvm::InstCombinerImpl::foldICmpUsingKnownBits(), llvm::InstCombinerImpl::foldICmpWithZero(), getBitWidth(), getConstant(), getKnownBitsFromAndXorOr(), llvm::GISelValueTracking::getKnownOnes(), getMinValue(), getSignedMaxValue(), getSignedMinValue(), hasConflict(), insertBits(), intersectWith(), isAllOnes(), isConstant(), llvm::SelectionDAG::isKnownNeverZero(), isKnownNonEqual(), isKnownNonZeroFromOperator(), llvm::isKnownToBeAPowerOfTwo(), isNegative(), isNonZero(), isNonZeroAdd(), isNonZeroMul(), isNonZeroShift(), isSignUnknown(), isStrictlyPositive(), isUnknown(), KnownBits(), makeGE(), makeNegative(), matchBinaryShuffle(), llvm::CombinerHelper::matchRedundantAnd(), llvm::CombinerHelper::matchRedundantOr(), mul(), operator&=(), operator<<=(), operator==(), operator>>=(), operator^=(), operator|=(), print(), resetAll(), reverseBits(), sdiv(), setAllConflict(), setAllOnes(), setAllZero(), sext(), sextInReg(), shl(), llvm::TargetLowering::SimplifyDemandedBits(), llvm::LoongArchTargetLowering::SimplifyDemandedBitsForTargetNode(), llvm::RISCVTargetLowering::SimplifyDemandedBitsForTargetNode(), llvm::X86TargetLowering::SimplifyDemandedBitsForTargetNode(), llvm::InstCombinerImpl::SimplifyDemandedUseBits(), llvm::InstCombinerImpl::SimplifyMultipleUseDemandedBits(), llvm::TargetLowering::SimplifyMultipleUseDemandedBits(), simplifyRightShift(), simplifyShift(), llvm::InstCombinerImpl::simplifyShrShlDemandedBits(), smin(), srem(), llvm::ConstantRange::toKnownBits(), trunc(), umin(), unionWith(), llvm::InstCombinerImpl::visitOr(), and zext().

◆ Zero

APInt llvm::KnownBits::Zero

Definition at line 25 of file KnownBits.h.

Referenced by abs(), llvm::FunctionLoweringInfo::AddLiveOutRegInfo(), adjustForRedundantAnd(), anyext(), ashr(), llvm::ConstantRange::binaryXor(), blsi(), blsmsk(), byteSwap(), combineSetCC(), computeForAddCarry(), computeForAddCarry(), computeForAddSub(), computeForSatAddSub(), computeForSubBorrow(), computeKnownBits(), llvm::SelectionDAG::computeKnownBits(), llvm::GISelValueTracking::computeKnownBitsForAlignment(), llvm::SITargetLowering::computeKnownBitsForFrameIndex(), llvm::TargetLowering::computeKnownBitsForFrameIndex(), computeKnownBitsForLoadV(), llvm::SITargetLowering::computeKnownBitsForTargetInstr(), llvm::AArch64TargetLowering::computeKnownBitsForTargetNode(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), llvm::ARMTargetLowering::computeKnownBitsForTargetNode(), llvm::LanaiTargetLowering::computeKnownBitsForTargetNode(), llvm::PPCTargetLowering::computeKnownBitsForTargetNode(), llvm::RISCVTargetLowering::computeKnownBitsForTargetNode(), llvm::SITargetLowering::computeKnownBitsForTargetNode(), llvm::SystemZTargetLowering::computeKnownBitsForTargetNode(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromCmp(), llvm::computeKnownBitsFromContext(), computeKnownBitsFromOperator(), llvm::computeKnownBitsFromRangeMetadata(), llvm::GISelValueTracking::computeKnownBitsImpl(), computeKnownBitsMul(), computeKnownFPClass(), llvm::SelectionDAG::ComputeNumSignBits(), llvm::GISelValueTracking::computeNumSignBits(), ComputeNumSignBitsImpl(), llvm::FunctionLoweringInfo::ComputePHILiveOutRegInfo(), concat(), countMaxLeadingOnes(), countMaxPopulation(), countMaxTrailingOnes(), countMinLeadingZeros(), countMinTrailingZeros(), llvm::DemandedBits::determineLiveOperandBitsSub(), divComputeLowBit(), dumpResult(), eliminateDeadSwitchCases(), extractBits(), llvm::InstCombinerImpl::foldAddWithConstant(), foldCtpop(), llvm::InstCombinerImpl::foldICmpTruncConstant(), llvm::InstCombinerImpl::foldICmpUsingKnownBits(), getBitWidth(), getKnownBitsFromAndXorOr(), llvm::GISelValueTracking::getKnownZeroes(), getMaxValue(), getSignedMaxValue(), getSignedMinValue(), hasConflict(), insertBits(), intersectWith(), isConstant(), isKnownNonEqual(), llvm::isKnownToBeAPowerOfTwo(), isNonNegative(), isNonZeroShift(), isSignUnknown(), isStrictlyPositive(), isTruncateOf(), isUnknown(), isZero(), KnownBits(), knownBitsForWorkitemID(), LowerMUL(), lshr(), makeGE(), makeNonNegative(), llvm::MaskedValueIsZero(), matchBinaryShuffle(), llvm::CombinerHelper::matchRedundantAnd(), llvm::CombinerHelper::matchRedundantOr(), mul(), operator&=(), operator<<=(), operator==(), operator>>=(), operator^=(), operator|=(), performANDCombine(), llvm::ARMTargetLowering::PerformCMOVCombine(), llvm::ARMTargetLowering::PerformCMOVToBFICombine(), performORCombine(), print(), provablyDisjointOr(), resetAll(), reverseBits(), sdiv(), llvm::PPCTargetLowering::SelectAddressRegImm(), llvm::PPCTargetLowering::SelectAddressRegImm34(), llvm::PPCTargetLowering::SelectAddressRegReg(), llvm::LoongArchDAGToDAGISel::selectShiftMask(), llvm::RISCVDAGToDAGISel::selectShiftMask(), setAllConflict(), setAllOnes(), setAllZero(), sext(), sextInReg(), shl(), llvm::simplifyBinaryIntrinsic(), llvm::TargetLowering::SimplifyDemandedBits(), llvm::LoongArchTargetLowering::SimplifyDemandedBitsForTargetNode(), llvm::RISCVTargetLowering::SimplifyDemandedBitsForTargetNode(), llvm::X86TargetLowering::SimplifyDemandedBitsForTargetNode(), llvm::InstCombinerImpl::SimplifyDemandedUseBits(), llvm::X86TTIImpl::simplifyDemandedUseBitsIntrinsic(), llvm::TargetLowering::SimplifyDemandedVectorElts(), llvm::InstCombinerImpl::SimplifyMultipleUseDemandedBits(), llvm::TargetLowering::SimplifyMultipleUseDemandedBits(), llvm::X86TargetLowering::SimplifyMultipleUseDemandedBitsForTargetNode(), simplifyShift(), llvm::InstCombinerImpl::simplifyShrShlDemandedBits(), simplifySubInst(), smin(), srem(), llvm::ConstantRange::toKnownBits(), trunc(), tryBitfieldInsertOpFromOr(), llvm::RISCVDAGToDAGISel::tryBitfieldInsertOpFromOrAndImm(), tryBitfieldInsertOpFromOrAndImm(), udiv(), umin(), unionWith(), urem(), llvm::InstCombinerImpl::visitSub(), and zext().


The documentation for this struct was generated from the following files: