LLVM: lib/Transforms/InstCombine/InstCombineAddSub.cpp File Reference

LLVM 22.0.0git

#include "InstCombineInternal.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/AlignOf.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Transforms/InstCombine/InstCombiner.h"
#include <cassert>
#include <utility>

Go to the source code of this file.

Macros
#define	DEBUG_TYPE "instcombine"

Functions
static Value *	checkForNegativeOperand (BinaryOperator &I, InstCombiner::BuilderTy &Builder)
static Instruction *	foldNoWrapAdd (BinaryOperator &Add, InstCombiner::BuilderTy &Builder)
	Wrapping flags may allow combining constants separated by an extend.
template<bool FP, typename Mul2Rhs>
static bool	matchesSquareSum (BinaryOperator &I, Mul2Rhs M2Rhs, Value &A, Value &B)
static bool	MatchMul (Value E, Value &Op, APInt &C)
static bool	MatchRem (Value E, Value &Op, APInt &C, bool &IsSigned)
static bool	MatchDiv (Value E, Value &Op, APInt &C, bool IsSigned)
static bool	MulWillOverflow (APInt &C0, APInt &C1, bool IsSigned)
static Instruction *	canonicalizeLowbitMask (BinaryOperator &I, InstCombiner::BuilderTy &Builder)
	Fold (1 << NBits) - 1 Into: ~(-(1 << NBits)) Because a 'not' is better for bit-tracking analysis and other transforms than an 'add'.
static Instruction *	foldToUnsignedSaturatedAdd (BinaryOperator &I)
static Instruction *	combineAddSubWithShlAddSub (InstCombiner::BuilderTy &Builder, const BinaryOperator &I)
static Instruction *	foldAddToAshr (BinaryOperator &Add)
	Try to reduce signed division by power-of-2 to an arithmetic shift right.
static Instruction *	factorizeMathWithShlOps (BinaryOperator &I, InstCombiner::BuilderTy &Builder)
	This is a specialization of a more general transform from foldUsingDistributiveLaws.
static Instruction *	foldBoxMultiply (BinaryOperator &I)
	Reduce a sequence of masked half-width multiplies to a single multiply.
static Instruction *	factorizeLerp (BinaryOperator &I, InstCombiner::BuilderTy &Builder)
	Eliminate an op from a linear interpolation (lerp) pattern.
static Instruction *	factorizeFAddFSub (BinaryOperator &I, InstCombiner::BuilderTy &Builder)
	Factor a common operand out of fadd/fsub of fmul/fdiv.
static Instruction *	foldSubOfMinMax (BinaryOperator &I, InstCombiner::BuilderTy &Builder)
static Instruction *	foldFNegIntoConstant (Instruction &I, const DataLayout &DL)
	This eliminates floating-point negation in either 'fneg(X)' or 'fsub(-0.0, X)' form by combining into a constant operand.

Macro Definition Documentation

◆ DEBUG_TYPE

#define DEBUG_TYPE "instcombine"

Definition at line 39 of file InstCombineAddSub.cpp.

Function Documentation

◆ canonicalizeLowbitMask()

Instruction * canonicalizeLowbitMask	(	BinaryOperator &	I,
		InstCombiner::BuilderTy &	Builder )

static

Fold (1 << NBits) - 1 Into: ~(-(1 << NBits)) Because a 'not' is better for bit-tracking analysis and other transforms than an 'add'.

The new shl is always nsw, and is nuw if old and was.

Definition at line 1221 of file InstCombineAddSub.cpp.

References llvm::BinaryOperator::CreateNot(), llvm::dyn_cast(), llvm::Constant::getAllOnesValue(), llvm::Value::getType(), I, llvm::PatternMatch::m_Add(), llvm::PatternMatch::m_AllOnes(), llvm::PatternMatch::m_One(), llvm::MIPatternMatch::m_OneUse(), llvm::PatternMatch::m_Shl(), llvm::PatternMatch::m_Value(), and llvm::PatternMatch::match().

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

◆ checkForNegativeOperand()

Value * checkForNegativeOperand	(	BinaryOperator &	I,
		InstCombiner::BuilderTy &	Builder )

static

Definition at line 752 of file InstCombineAddSub.cpp.

References llvm::APInt::countr_zero(), I, LHS, llvm::PatternMatch::m_Add(), llvm::PatternMatch::m_And(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_One(), llvm::PatternMatch::m_Or(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::m_Xor(), llvm::PatternMatch::match(), RHS, std::swap(), X, and Y.

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

◆ combineAddSubWithShlAddSub()

Instruction * combineAddSubWithShlAddSub	(	InstCombiner::BuilderTy &	Builder,
		const BinaryOperator &	I )

static

Definition at line 1265 of file InstCombineAddSub.cpp.

References A(), B(), I, llvm::PatternMatch::m_c_Add(), llvm::MIPatternMatch::m_Neg(), llvm::MIPatternMatch::m_OneUse(), llvm::PatternMatch::m_Shl(), llvm::PatternMatch::m_Value(), and llvm::PatternMatch::match().

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

◆ factorizeFAddFSub()

Instruction * factorizeFAddFSub	(	BinaryOperator &	I,
		InstCombiner::BuilderTy &	Builder )

static

Factor a common operand out of fadd/fsub of fmul/fdiv.

Definition at line 1942 of file InstCombineAddSub.cpp.

References assert(), llvm::CallingConv::C, llvm::BinaryOperator::CreateFDivFMF(), llvm::BinaryOperator::CreateFMulFMF(), factorizeLerp(), llvm::Value::hasOneUse(), I, llvm::PatternMatch::m_APFloat(), llvm::PatternMatch::m_c_FMul(), llvm::PatternMatch::m_FDiv(), llvm::PatternMatch::m_FMul(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), X, and Y.

Referenced by llvm::InstCombinerImpl::visitFAdd(), and llvm::InstCombinerImpl::visitFSub().

◆ factorizeLerp()

Instruction * factorizeLerp	(	BinaryOperator &	I,
		InstCombiner::BuilderTy &	Builder )

static

Eliminate an op from a linear interpolation (lerp) pattern.

Definition at line 1926 of file InstCombineAddSub.cpp.

References llvm::BinaryOperator::CreateFAddFMF(), I, llvm::PatternMatch::m_c_FAdd(), llvm::PatternMatch::m_c_FMul(), llvm::PatternMatch::m_Deferred(), llvm::PatternMatch::m_FPOne(), llvm::PatternMatch::m_FSub(), llvm::MIPatternMatch::m_OneUse(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), X, and Y.

Referenced by factorizeFAddFSub().

◆ factorizeMathWithShlOps()

Instruction * factorizeMathWithShlOps	(	BinaryOperator &	I,
		InstCombiner::BuilderTy &	Builder )

static

This is a specialization of a more general transform from foldUsingDistributiveLaws.

If that code can be made to work optimally for multi-use cases or propagating nsw/nuw, then we would not need this.

Definition at line 1446 of file InstCombineAddSub.cpp.

References assert(), llvm::dyn_cast(), I, llvm::PatternMatch::m_Shl(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), X, and Y.

Referenced by llvm::InstCombinerImpl::visitAdd(), and llvm::InstCombinerImpl::visitSub().

◆ foldAddToAshr()

Instruction * foldAddToAshr ( BinaryOperator & Add )

static

Try to reduce signed division by power-of-2 to an arithmetic shift right.

Definition at line 1278 of file InstCombineAddSub.cpp.

References llvm::Add, llvm::APInt::exactLogBase2(), llvm::APInt::getSignedMinValue(), llvm::CmpInst::ICMP_EQ, llvm::CmpInst::ICMP_UGT, llvm::APInt::isNegative(), llvm::APInt::isSignMask(), llvm::PatternMatch::m_And(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_ICmp(), llvm::PatternMatch::m_Power2(), llvm::PatternMatch::m_SDiv(), llvm::PatternMatch::m_SExt(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), llvm::SMin, and X.

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

◆ foldBoxMultiply()

Instruction * foldBoxMultiply ( BinaryOperator & I )

static

Reduce a sequence of masked half-width multiplies to a single multiply.

((XLow * YHigh) + (YLow * XHigh)) << HalfBits) + (XLow * YLow) --> X * Y

Definition at line 1482 of file InstCombineAddSub.cpp.

References llvm::BitWidth, llvm::APInt::getMaxValue(), I, llvm::PatternMatch::m_And(), llvm::PatternMatch::m_c_Add(), llvm::PatternMatch::m_c_Mul(), llvm::PatternMatch::m_CombineOr(), llvm::PatternMatch::m_LShr(), llvm::PatternMatch::m_Mul(), llvm::MIPatternMatch::m_OneUse(), llvm::PatternMatch::m_Shl(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_SpecificInt(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), X, and Y.

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

◆ foldFNegIntoConstant()

Instruction * foldFNegIntoConstant	(	Instruction &	I,
		const DataLayout &	DL )

static

This eliminates floating-point negation in either 'fneg(X)' or 'fsub(-0.0, X)' form by combining into a constant operand.

Definition at line 2949 of file InstCombineAddSub.cpp.

References llvm::CallingConv::C, llvm::ConstantFoldUnaryOpOperand(), llvm::BinaryOperator::CreateFDivFMF(), llvm::BinaryOperator::CreateFMulFMF(), llvm::BinaryOperator::CreateFSubFMF(), DL, llvm::Instruction::getFastMathFlags(), I, llvm::FastMathFlags::intersectRewrite(), llvm::PatternMatch::m_Constant(), llvm::PatternMatch::m_FAdd(), llvm::PatternMatch::m_FDiv(), llvm::PatternMatch::m_FMul(), llvm::PatternMatch::m_FNeg(), llvm::PatternMatch::m_Instruction(), llvm::MIPatternMatch::m_OneUse(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), llvm::FastMathFlags::noInfs(), llvm::FastMathFlags::noSignedZeros(), llvm::Instruction::setHasNoInfs(), llvm::Instruction::setHasNoSignedZeros(), llvm::FastMathFlags::setNoInfs(), llvm::FastMathFlags::unionValue(), and X.

Referenced by llvm::InstCombinerImpl::visitFNeg(), and llvm::InstCombinerImpl::visitFSub().

◆ foldNoWrapAdd()

Instruction * foldNoWrapAdd	(	BinaryOperator &	Add,
		InstCombiner::BuilderTy &	Builder )

static

Wrapping flags may allow combining constants separated by an extend.

Definition at line 809 of file InstCombineAddSub.cpp.

References llvm::Add, llvm::APInt::getBitWidth(), llvm::Value::hasOneUse(), llvm::APInt::isNegative(), llvm::APInt::isZero(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_Constant(), llvm::PatternMatch::m_NSWAddLike(), llvm::PatternMatch::m_NUWAddLike(), llvm::MIPatternMatch::m_OneUse(), llvm::PatternMatch::m_SExtLike(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::m_ZExt(), llvm::PatternMatch::match(), llvm::APInt::sext(), llvm::APInt::sge(), llvm::APInt::trunc(), and X.

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

◆ foldSubOfMinMax()

Instruction * foldSubOfMinMax	(	BinaryOperator &	I,
		InstCombiner::BuilderTy &	Builder )

static

◆ foldToUnsignedSaturatedAdd()

Instruction * foldToUnsignedSaturatedAdd ( BinaryOperator & I )

static

Definition at line 1239 of file InstCombineAddSub.cpp.

References assert(), llvm::CallingConv::C, llvm::CallInst::Create(), llvm::Intrinsic::getOrInsertDeclaration(), I, llvm::PatternMatch::m_Add(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_c_Add(), llvm::PatternMatch::m_c_UMin(), llvm::PatternMatch::m_Deferred(), llvm::MIPatternMatch::m_Not(), llvm::PatternMatch::m_UMin(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), X, and Y.

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

◆ MatchDiv()

bool MatchDiv	(	Value *	E,
		Value *&	Op,
		APInt &	C,
		bool	IsSigned )

static

Definition at line 1122 of file InstCombineAddSub.cpp.

References llvm::CallingConv::C, E(), llvm::APInt::getBitWidth(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_LShr(), llvm::PatternMatch::m_SDiv(), llvm::PatternMatch::m_UDiv(), llvm::PatternMatch::m_Value(), and llvm::PatternMatch::match().

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

◆ matchesSquareSum()

template<bool FP, typename Mul2Rhs>

bool matchesSquareSum	(	BinaryOperator &	I,
		Mul2Rhs	M2Rhs,
		Value *&	A,
		Value *&	B )

static

Definition at line 1025 of file InstCombineAddSub.cpp.

References A(), B(), FP, I, llvm::PatternMatch::m_BinOp(), llvm::PatternMatch::m_c_BinOp(), llvm::PatternMatch::m_CombineOr(), llvm::PatternMatch::m_Deferred(), llvm::MIPatternMatch::m_OneUse(), llvm::PatternMatch::m_Value(), and llvm::PatternMatch::match().

Referenced by llvm::InstCombinerImpl::foldSquareSumFP(), and llvm::InstCombinerImpl::foldSquareSumInt().

◆ MatchMul()

bool MatchMul	(	Value *	E,
		Value *&	Op,
		APInt &	C )

static

Definition at line 1082 of file InstCombineAddSub.cpp.

References llvm::CallingConv::C, E(), llvm::APInt::getBitWidth(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_Mul(), llvm::PatternMatch::m_Shl(), llvm::PatternMatch::m_Value(), and llvm::PatternMatch::match().

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

◆ MatchRem()

bool MatchRem	(	Value *	E,
		Value *&	Op,
		APInt &	C,
		bool &	IsSigned )

static

Definition at line 1100 of file InstCombineAddSub.cpp.

References llvm::CallingConv::C, E(), llvm::PatternMatch::m_And(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_SRem(), llvm::PatternMatch::m_URem(), llvm::PatternMatch::m_Value(), and llvm::PatternMatch::match().

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

◆ MulWillOverflow()

bool MulWillOverflow	(	APInt &	C0,
		APInt &	C1,
		bool	IsSigned )

static

Definition at line 1143 of file InstCombineAddSub.cpp.

References llvm::APInt::smul_ov(), and llvm::APInt::umul_ov().

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