TargetLowering.cpp File Reference

#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Analysis/VectorUtils.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/CodeGenCommonISel.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/Support/DivisionByConstantInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetMachine.h"
#include <cctype>

Go to the source code of this file.

Functions
static SDValue	combineShiftToAVG (SDValue Op, TargetLowering::TargetLoweringOpt &TLO, const TargetLowering &TLI, const APInt &DemandedBits, const APInt &DemandedElts, unsigned Depth)
static APInt	getKnownUndefForVectorBinop (SDValue BO, SelectionDAG &DAG, const APInt &UndefOp0, const APInt &UndefOp1)
	Given a vector binary operation and known undefined elements for each input operand, compute whether each element of the output is undefined.
static SDValue	simplifySetCCWithCTPOP (const TargetLowering &TLI, EVT VT, SDValue N0, const APInt &C1, ISD::CondCode Cond, const SDLoc &dl, SelectionDAG &DAG)
static SDValue	foldSetCCWithRotate (EVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond, const SDLoc &dl, SelectionDAG &DAG)
static SDValue	foldSetCCWithFunnelShift (EVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond, const SDLoc &dl, SelectionDAG &DAG)
static unsigned	getConstraintPiority (TargetLowering::ConstraintType CT)
	Return a number indicating our preference for chosing a type of constraint over another, for the purpose of sorting them.
static bool	lowerImmediateIfPossible (TargetLowering::ConstraintPair &P, SDValue Op, SelectionDAG *DAG, const TargetLowering &TLI)
	If we have an immediate, see if we can lower it.
static SDValue	BuildExactSDIV (const TargetLowering &TLI, SDNode *N, const SDLoc &dl, SelectionDAG &DAG, SmallVectorImpl< SDNode * > &Created)
	Given an exact SDIV by a constant, create a multiplication with the multiplicative inverse of the constant.
static SDValue	BuildExactUDIV (const TargetLowering &TLI, SDNode *N, const SDLoc &dl, SelectionDAG &DAG, SmallVectorImpl< SDNode * > &Created)
	Given an exact UDIV by a constant, create a multiplication with the multiplicative inverse of the constant.
static void	turnVectorIntoSplatVector (MutableArrayRef< SDValue > Values, std::function< bool(SDValue)> Predicate, SDValue AlternativeReplacement=SDValue())
	If all values in Values that don't match the predicate are same 'splat' value, then replace all values with that splat value.
static bool	isNonZeroModBitWidthOrUndef (SDValue Z, unsigned BW)
static SDValue	expandVPFunnelShift (SDNode *Node, SelectionDAG &DAG)
static std::optional< bool >	isFCmpEqualZero (FPClassTest Test, const fltSemantics &Semantics, const MachineFunction &MF)
	Returns a true value if if this FPClassTest can be performed with an ordered fcmp to 0, and a false value if it's an unordered fcmp to 0.
static bool	canExpandVectorCTPOP (const TargetLowering &TLI, EVT VT)
static SDValue	clampDynamicVectorIndex (SelectionDAG &DAG, SDValue Idx, EVT VecVT, const SDLoc &dl, ElementCount SubEC)

Function Documentation

BuildExactSDIV()

static SDValue BuildExactSDIV ( const TargetLowering &  TLI, SDNode *  N, const SDLoc &  dl, SelectionDAG &  DAG, SmallVectorImpl< SDNode * > &  Created  )

static

Given an exact SDIV by a constant, create a multiplication with the multiplicative inverse of the constant.

Ref: "Hacker's Delight" by Henry Warren, 2nd Edition, p. 242

Definition at line 6147 of file TargetLowering.cpp.

References llvm::APInt::ashrInPlace(), assert(), llvm::ISD::BUILD_VECTOR, llvm::CallingConv::C, llvm::APInt::countr_zero(), llvm::SDNodeFlags::Exact, llvm::SelectionDAG::getBuildVector(), llvm::SelectionDAG::getConstant(), llvm::SelectionDAG::getDataLayout(), llvm::SDValue::getNode(), llvm::SelectionDAG::getNode(), llvm::SDValue::getOpcode(), llvm::EVT::getScalarType(), llvm::TargetLoweringBase::getShiftAmountTy(), llvm::SelectionDAG::getSplatVector(), llvm::ISD::matchUnaryPredicate(), llvm::ISD::MUL, llvm::APInt::multiplicativeInverse(), N, llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::SmallVectorBase< Size_T >::size(), llvm::ISD::SPLAT_VECTOR, and llvm::ISD::SRA.

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

BuildExactUDIV()

static SDValue BuildExactUDIV ( const TargetLowering &  TLI, SDNode *  N, const SDLoc &  dl, SelectionDAG &  DAG, SmallVectorImpl< SDNode * > &  Created  )

static

Given an exact UDIV by a constant, create a multiplication with the multiplicative inverse of the constant.

Ref: "Hacker's Delight" by Henry Warren, 2nd Edition, p. 242

Definition at line 6207 of file TargetLowering.cpp.

References assert(), llvm::ISD::BUILD_VECTOR, llvm::CallingConv::C, llvm::APInt::countr_zero(), llvm::SDNodeFlags::Exact, llvm::SelectionDAG::getBuildVector(), llvm::SelectionDAG::getConstant(), llvm::SelectionDAG::getDataLayout(), llvm::SDValue::getNode(), llvm::SelectionDAG::getNode(), llvm::SDValue::getOpcode(), llvm::EVT::getScalarType(), llvm::TargetLoweringBase::getShiftAmountTy(), llvm::SelectionDAG::getSplatVector(), llvm::APInt::lshrInPlace(), llvm::ISD::matchUnaryPredicate(), llvm::ISD::MUL, llvm::APInt::multiplicativeInverse(), N, llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::SmallVectorBase< Size_T >::size(), llvm::ISD::SPLAT_VECTOR, and llvm::ISD::SRL.

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

canExpandVectorCTPOP()

static bool canExpandVectorCTPOP ( const TargetLowering &  TLI, EVT  VT  )

static

Definition at line 9073 of file TargetLowering.cpp.

References llvm::ISD::ADD, llvm::ISD::AND, assert(), llvm::EVT::getScalarSizeInBits(), llvm::TargetLoweringBase::isOperationLegalOrCustom(), llvm::TargetLoweringBase::isOperationLegalOrCustomOrPromote(), llvm::EVT::isVector(), llvm::ISD::MUL, llvm::ISD::SRL, and llvm::ISD::SUB.

Referenced by llvm::TargetLowering::expandCTLZ(), llvm::TargetLowering::expandCTPOP(), and llvm::TargetLowering::expandCTTZ().

clampDynamicVectorIndex()

static SDValue clampDynamicVectorIndex ( SelectionDAG &  DAG, SDValue  Idx, EVT  VecVT, const SDLoc &  dl, ElementCount  SubEC  )

static

Definition at line 10449 of file TargetLowering.cpp.

References llvm::ISD::AND, assert(), llvm::SelectionDAG::getConstant(), llvm::EVT::getFixedSizeInBits(), llvm::details::FixedOrScalableQuantity< LeafTy, ValueTy >::getKnownMinValue(), llvm::APInt::getLowBitsSet(), llvm::SelectionDAG::getNode(), llvm::EVT::getSizeInBits(), llvm::EVT::getVectorMinNumElements(), llvm::SelectionDAG::getVScale(), Idx, llvm::EVT::isFixedLengthVector(), llvm::isPowerOf2_32(), llvm::details::FixedOrScalableQuantity< LeafTy, ValueTy >::isScalable(), llvm::EVT::isScalableVector(), llvm::Log2_32(), llvm::ISD::SUB, llvm::ISD::UMIN, and llvm::ISD::USUBSAT.

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

combineShiftToAVG()

static SDValue combineShiftToAVG ( SDValue  Op, TargetLowering::TargetLoweringOpt &  TLO, const TargetLowering &  TLI, const APInt &  DemandedBits, const APInt &  DemandedElts, unsigned  Depth  )

static

Definition at line 987 of file TargetLowering.cpp.

References A, llvm::Add, llvm::ISD::ADD, assert(), llvm::ISD::AVGCEILS, llvm::ISD::AVGCEILU, llvm::ISD::AVGFLOORS, llvm::ISD::AVGFLOORU, llvm::bit_ceil(), llvm::SelectionDAG::computeKnownBits(), llvm::SelectionDAG::ComputeNumSignBits(), llvm::KnownBits::countMinLeadingZeros(), llvm::TargetLowering::TargetLoweringOpt::DAG, llvm::Depth, DL, llvm::SelectionDAG::getContext(), llvm::SelectionDAG::getExtOrTrunc(), llvm::EVT::getIntegerVT(), llvm::SelectionDAG::getNode(), llvm::SDValue::getOpcode(), llvm::SDValue::getOperand(), llvm::EVT::getScalarSizeInBits(), llvm::EVT::getVectorElementCount(), llvm::EVT::getVectorVT(), llvm::isConstOrConstSplat(), llvm::ConstantSDNode::isOne(), llvm::TargetLoweringBase::isOperationLegal(), llvm::EVT::isVector(), llvm::TargetLowering::TargetLoweringOpt::LegalOperations(), llvm::TargetLowering::TargetLoweringOpt::LegalTypes(), llvm_unreachable, llvm::ISD::SRA, llvm::ISD::SRL, and llvm::SelectionDAG::willNotOverflowAdd().

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

expandVPFunnelShift()

static SDValue expandVPFunnelShift ( SDNode *  Node, SelectionDAG &  DAG  )

static

Definition at line 7977 of file TargetLowering.cpp.

References DL, llvm::SelectionDAG::getAllOnesConstant(), llvm::SelectionDAG::getConstant(), llvm::SelectionDAG::getNode(), llvm::EVT::getScalarSizeInBits(), isNonZeroModBitWidthOrUndef(), llvm::isPowerOf2_32(), X, and Y.

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

foldSetCCWithFunnelShift()

static SDValue foldSetCCWithFunnelShift ( EVT  VT, SDValue  N0, SDValue  N1, ISD::CondCode  Cond, const SDLoc &  dl, SelectionDAG &  DAG  )

static

Definition at line 4437 of file TargetLowering.cpp.

References llvm::BitWidth, Cond, llvm::ISD::FSHL, llvm::ISD::FSHR, llvm::SelectionDAG::getConstant(), llvm::SelectionDAG::getNode(), llvm::SDValue::getOpcode(), llvm::SDValue::getOperand(), llvm::SDValue::getScalarValueSizeInBits(), llvm::SelectionDAG::getSetCC(), llvm::SDValue::getValueType(), llvm::SDValue::hasOneUse(), llvm::isConstOrConstSplat(), llvm::ConstantSDNode::isZero(), llvm::Or, llvm::ISD::OR, llvm::Other, llvm::ISD::SETEQ, llvm::ISD::SETNE, llvm::ISD::SHL, llvm::ISD::SRL, X, and Y.

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

foldSetCCWithRotate()

static SDValue foldSetCCWithRotate ( EVT  VT, SDValue  N0, SDValue  N1, ISD::CondCode  Cond, const SDLoc &  dl, SelectionDAG &  DAG  )

static

Definition at line 4394 of file TargetLowering.cpp.

References Cond, llvm::SelectionDAG::getNode(), llvm::SDValue::getOpcode(), llvm::SDValue::getOperand(), llvm::SelectionDAG::getSetCC(), llvm::SDValue::getValueType(), llvm::SDValue::hasOneUse(), llvm::ConstantSDNode::isAllOnes(), llvm::isConstOrConstSplat(), llvm::ConstantSDNode::isZero(), llvm::ISD::OR, llvm::ISD::ROTL, llvm::ISD::ROTR, llvm::ISD::SETEQ, llvm::ISD::SETNE, and X.

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

getConstraintPiority()

static unsigned getConstraintPiority ( TargetLowering::ConstraintType  CT )

static

Return a number indicating our preference for chosing a type of constraint over another, for the purpose of sorting them.

Immediates are almost always preferrable (when they can be emitted). A higher return value means a stronger preference for one constraint type relative to another. FIXME: We should prefer registers over memory but doing so may lead to unrecoverable register exhaustion later. https://github.com/llvm/llvm-project/issues/20571

Definition at line 5923 of file TargetLowering.cpp.

References llvm::TargetLowering::C_Address, llvm::TargetLowering::C_Immediate, llvm::TargetLowering::C_Memory, llvm::TargetLowering::C_Other, llvm::TargetLowering::C_Register, llvm::TargetLowering::C_RegisterClass, llvm::TargetLowering::C_Unknown, and llvm_unreachable.

getKnownUndefForVectorBinop()

static APInt getKnownUndefForVectorBinop ( SDValue  BO, SelectionDAG &  DAG, const APInt &  UndefOp0, const APInt &  UndefOp1  )

static

Given a vector binary operation and known undefined elements for each input operand, compute whether each element of the output is undefined.

Definition at line 3031 of file TargetLowering.cpp.

References assert(), llvm::CallingConv::C, llvm::APInt::getBitWidth(), llvm::SelectionDAG::getNode(), llvm::SDValue::getOpcode(), llvm::SDValue::getOperand(), llvm::SDNode::getOperand(), llvm::SelectionDAG::getTargetLoweringInfo(), llvm::SelectionDAG::getUNDEF(), llvm::SDValue::getValueType(), llvm::EVT::getVectorElementType(), llvm::EVT::getVectorNumElements(), llvm::APInt::getZero(), llvm::TargetLoweringBase::isBinOp(), llvm::EVT::isFixedLengthVector(), llvm::SDValue::isUndef(), isUndef(), llvm::EVT::isVector(), and llvm::APInt::setBit().

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

isFCmpEqualZero()

static std::optional< bool > isFCmpEqualZero ( FPClassTest  Test, const fltSemantics &  Semantics, const MachineFunction &  MF  )

static

Returns a true value if if this FPClassTest can be performed with an ordered fcmp to 0, and a false value if it's an unordered fcmp to 0.

Returns std::nullopt if it cannot be performed as a compare with 0.

Definition at line 8703 of file TargetLowering.cpp.

References llvm::fcNan, llvm::fcNone, llvm::fcSubnormal, llvm::fcZero, llvm::MachineFunction::getDenormalMode(), llvm::DenormalMode::IEEE, llvm::DenormalMode::Input, llvm::DenormalMode::inputsAreZero(), and llvm::Test.

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

isNonZeroModBitWidthOrUndef()

static bool isNonZeroModBitWidthOrUndef ( SDValue  Z, unsigned  BW  )

static

Definition at line 7970 of file TargetLowering.cpp.

References llvm::CallingConv::C, and llvm::ISD::matchUnaryPredicate().

lowerImmediateIfPossible()

static bool lowerImmediateIfPossible ( TargetLowering::ConstraintPair &  P, SDValue  Op, SelectionDAG *  DAG, const TargetLowering &  TLI  )

static

If we have an immediate, see if we can lower it.

Return true if we can, false otherwise.

Definition at line 6070 of file TargetLowering.cpp.

References assert(), llvm::TargetLowering::C_Immediate, llvm::TargetLowering::C_Other, llvm::TargetLowering::LowerAsmOperandForConstraint(), and P.

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

simplifySetCCWithCTPOP()

static SDValue simplifySetCCWithCTPOP ( const TargetLowering &  TLI, EVT  VT, SDValue  N0, const APInt &  C1, ISD::CondCode  Cond, const SDLoc &  dl, SelectionDAG &  DAG  )

static

Definition at line 4320 of file TargetLowering.cpp.

References llvm::Add, llvm::ISD::ADD, llvm::And, llvm::ISD::AND, assert(), CC, Cond, llvm::ISD::CTPOP, llvm::SelectionDAG::getAllOnesConstant(), llvm::SelectionDAG::getConstant(), llvm::TargetLoweringBase::getCustomCtpopCost(), llvm::APInt::getLimitedValue(), llvm::SelectionDAG::getNode(), llvm::SDValue::getOpcode(), llvm::SDValue::getOperand(), llvm::SDValue::getScalarValueSizeInBits(), llvm::SelectionDAG::getSetCC(), llvm::SDValue::hasOneUse(), llvm::TargetLoweringBase::isCtpopFast(), llvm::EVT::isInteger(), llvm::SelectionDAG::isKnownNeverZero(), llvm::EVT::isVector(), llvm::Log2_32(), Passes, RHS, llvm::ISD::SETEQ, llvm::ISD::SETNE, llvm::ISD::SETUGT, llvm::ISD::SETULE, llvm::ISD::SETULT, llvm::ISD::TRUNCATE, llvm::APInt::ugt(), llvm::Xor, and llvm::ISD::XOR.

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

turnVectorIntoSplatVector()

static void turnVectorIntoSplatVector ( MutableArrayRef< SDValue >  Values, std::function< bool(SDValue)>  Predicate, SDValue  AlternativeReplacement = SDValue()  )

static

If all values in Values that don't match the predicate are same 'splat' value, then replace all values with that splat value.

Else, if AlternativeReplacement was provided, then replace all values that do match predicate with AlternativeReplacement value.

Definition at line 6700 of file TargetLowering.cpp.

References llvm::all_of(), llvm::MutableArrayRef< T >::begin(), llvm::MutableArrayRef< T >::end(), and llvm::find_if_not().