InstructionCombining.cpp File Reference

#include "InstCombineInternal.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SetOperations.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/BasicAliasAnalysis.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LastRunTrackingAnalysis.h"
#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/TargetFolder.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Analysis/Utils/Local.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Analysis/VectorUtils.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/EHPersonalities.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/ProfDataUtils.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Use.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/DebugCounter.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/KnownFPClass.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/InstCombine/InstCombine.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <memory>
#include <optional>
#include <string>
#include <utility>
#include "llvm/Transforms/Utils/InstructionWorklist.h"

Go to the source code of this file.

Classes
class	AliasScopeTracker

Macros
#define	DEBUG_TYPE   "instcombine"

Functions
	STATISTIC (NumWorklistIterations, "Number of instruction combining iterations performed")
	STATISTIC (NumOneIteration, "Number of functions with one iteration")
	STATISTIC (NumTwoIterations, "Number of functions with two iterations")
	STATISTIC (NumThreeIterations, "Number of functions with three iterations")
	STATISTIC (NumFourOrMoreIterations, "Number of functions with four or more iterations")
	STATISTIC (NumCombined, "Number of insts combined")
	STATISTIC (NumConstProp, "Number of constant folds")
	STATISTIC (NumDeadInst, "Number of dead inst eliminated")
	STATISTIC (NumSunkInst, "Number of instructions sunk")
	STATISTIC (NumExpand, "Number of expansions")
	STATISTIC (NumFactor, "Number of factorizations")
	STATISTIC (NumReassoc, "Number of reassociations")
	DEBUG_COUNTER (VisitCounter, "instcombine-visit", "Controls which instructions are visited")
static bool	maintainNoSignedWrap (BinaryOperator &I, Value *B, Value *C)
static bool	hasNoUnsignedWrap (BinaryOperator &I)
static bool	hasNoSignedWrap (BinaryOperator &I)
static bool	simplifyAssocCastAssoc (BinaryOperator *BinOp1, InstCombinerImpl &IC)
	Combine constant operands of associative operations either before or after a cast to eliminate one of the associative operations: (op (cast (op X, C2)), C1) --> (cast (op X, op (C1, C2))) (op (cast (op X, C2)), C1) --> (op (cast X), op (C1, C2))
static bool	leftDistributesOverRight (Instruction::BinaryOps LOp, Instruction::BinaryOps ROp)
	Return whether "X LOp (Y ROp Z)" is always equal to "(X LOp Y) ROp (X LOp Z)".
static bool	rightDistributesOverLeft (Instruction::BinaryOps LOp, Instruction::BinaryOps ROp)
	Return whether "(X LOp Y) ROp Z" is always equal to "(X ROp Z) LOp (Y ROp Z)".
static Value *	getIdentityValue (Instruction::BinaryOps Opcode, Value *V)
	This function returns identity value for given opcode, which can be used to factor patterns like (X * 2) + X ==> (X * 2) + (X * 1) ==> X * (2 + 1).
static Instruction::BinaryOps	getBinOpsForFactorization (Instruction::BinaryOps TopOpcode, BinaryOperator *Op, Value *&LHS, Value *&RHS, BinaryOperator *OtherOp)
	This function predicates factorization using distributive laws.
static Value *	tryFactorization (BinaryOperator &I, const SimplifyQuery &SQ, InstCombiner::BuilderTy &Builder, Instruction::BinaryOps InnerOpcode, Value *A, Value *B, Value *C, Value *D)
	This tries to simplify binary operations by factorizing out common terms (e.
static std::optional< std::pair< Value *, Value * > >	matchSymmetricPhiNodesPair (PHINode *LHS, PHINode *RHS)
static Value *	simplifyOperationIntoSelectOperand (Instruction &I, SelectInst *SI, bool IsTrueArm)
static Value *	foldOperationIntoSelectOperand (Instruction &I, SelectInst *SI, Value *NewOp, InstCombiner &IC)
static Value *	simplifyInstructionWithPHI (Instruction &I, PHINode *PN, Value *InValue, BasicBlock *InBB, const DataLayout &DL, const SimplifyQuery SQ)
static bool	shouldMergeGEPs (GEPOperator &GEP, GEPOperator &Src)
static Constant *	constantFoldBinOpWithSplat (unsigned Opcode, Constant *Vector, Constant *Splat, bool SplatLHS, const DataLayout &DL)
template<Intrinsic::ID SpliceID>
static Instruction *	foldSpliceBinOp (BinaryOperator &Inst, InstCombiner::BuilderTy &Builder)
static GEPNoWrapFlags	getMergedGEPNoWrapFlags (GEPOperator &GEP1, GEPOperator &GEP2)
	Determine nowrap flags for (gep (gep p, x), y) to (gep p, (x + y)) transform.
static Instruction *	foldSelectGEP (GetElementPtrInst &GEP, InstCombiner::BuilderTy &Builder)
	Thread a GEP operation with constant indices through the constant true/false arms of a select.
static Instruction *	canonicalizeGEPOfConstGEPI8 (GetElementPtrInst &GEP, GEPOperator *Src, InstCombinerImpl &IC)
static Instruction *	combineConstantOffsets (GetElementPtrInst &GEP, InstCombinerImpl &IC)
	Combine constant offsets separated by variable offsets.
static bool	shouldCanonicalizeGEPToPtrAdd (GetElementPtrInst &GEP)
	Return true if we should canonicalize the gep to an i8 ptradd.
static Instruction *	foldGEPOfPhi (GetElementPtrInst &GEP, PHINode *PN, IRBuilderBase &Builder)
static bool	isNeverEqualToUnescapedAlloc (Value *V, const TargetLibraryInfo &TLI, Instruction *AI)
static bool	isRemovableWrite (CallBase &CB, Value *UsedV, const TargetLibraryInfo &TLI)
	Given a call CB which uses an address UsedV, return true if we can prove the call's only possible effect is storing to V.
static std::optional< ModRefInfo >	isAllocSiteRemovable (Instruction *AI, SmallVectorImpl< Instruction * > &Users, const TargetLibraryInfo &TLI, bool KnowInit, unsigned MaxUsers)
static Instruction *	tryToMoveFreeBeforeNullTest (CallInst &FI, const DataLayout &DL)
	Move the call to free before a NULL test.
static Value *	simplifySwitchOnSelectUsingRanges (SwitchInst &SI, SelectInst *Select, bool IsTrueArm)
static Value *	foldFrexpOfSelect (ExtractValueInst &EV, IntrinsicInst *FrexpCall, SelectInst *SelectInst, InstCombiner::BuilderTy &Builder)
static bool	isCatchAll (EHPersonality Personality, Constant *TypeInfo)
	Return 'true' if the given typeinfo will match anything.
static bool	shorter_filter (const Value *LHS, const Value *RHS)
static bool	isUsedWithinShuffleVector (Value *V)
static bool	SoleWriteToDeadLocal (Instruction *I, TargetLibraryInfo &TLI)
	Check for case where the call writes to an otherwise dead alloca.
static bool	combineInstructionsOverFunction (Function &F, InstructionWorklist &Worklist, AliasAnalysis *AA, AssumptionCache &AC, TargetLibraryInfo &TLI, TargetTransformInfo &TTI, DominatorTree &DT, OptimizationRemarkEmitter &ORE, BlockFrequencyInfo *BFI, BranchProbabilityInfo *BPI, ProfileSummaryInfo *PSI, const InstCombineOptions &Opts)
	INITIALIZE_PASS_BEGIN (InstructionCombiningPass, "instcombine", "Combine redundant instructions", false, false) INITIALIZE_PASS_END(InstructionCombiningPass

Variables
	instcombine
Combine redundant	instructions
Combine redundant	false

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "instcombine"

Definition at line 112 of file InstructionCombining.cpp.

Function Documentation

canonicalizeGEPOfConstGEPI8()

Instruction * canonicalizeGEPOfConstGEPI8 ( GetElementPtrInst & GEP, GEPOperator * Src, InstCombinerImpl & IC )

static

Definition at line 2812 of file InstructionCombining.cpp.

References llvm::sampleprof::Base, llvm::InstCombiner::Builder, llvm::cast(), llvm::GetElementPtrInst::Create(), llvm::IRBuilderBase::CreatePtrAdd(), DL, GEP, llvm::APInt::getBitWidth(), llvm::InstCombiner::getDataLayout(), llvm::IRBuilderBase::getInt(), llvm::Type::getScalarType(), llvm::GEPNoWrapFlags::inBounds(), llvm::isa(), llvm::APInt::isZero(), llvm::PatternMatch::m_AddLike(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_NUWAddLike(), llvm::PatternMatch::m_PtrAdd(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), llvm::GEPNoWrapFlags::none(), and llvm::GEPNoWrapFlags::noUnsignedWrap().

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

combineConstantOffsets()

Instruction * combineConstantOffsets ( GetElementPtrInst & GEP, InstCombinerImpl & IC )

static

Combine constant offsets separated by variable offsets.

ptradd (ptradd (ptradd p, C1), x), C2 -> ptradd (ptradd p, x), C1+C2

Definition at line 2857 of file InstructionCombining.cpp.

References llvm::GEPNoWrapFlags::all(), llvm::InstCombiner::Builder, llvm::IRBuilderBase::CreatePtrAdd(), DL, llvm::dyn_cast(), GEP, llvm::InstCombiner::getDataLayout(), llvm::IRBuilderBase::getInt(), llvm::GEPNoWrapFlags::intersectForOffsetAdd(), llvm::GEPNoWrapFlags::intersectForReassociate(), llvm::Offset, llvm::InstCombiner::replaceInstUsesWith(), and llvm::InstCombiner::replaceOperand().

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

combineInstructionsOverFunction()

bool combineInstructionsOverFunction ( Function & F, InstructionWorklist & Worklist, AliasAnalysis * AA, AssumptionCache & AC, TargetLibraryInfo & TLI, TargetTransformInfo & TTI, DominatorTree & DT, OptimizationRemarkEmitter & ORE, BlockFrequencyInfo * BFI, BranchProbabilityInfo * BPI, ProfileSummaryInfo * PSI, const InstCombineOptions & Opts )

static

Definition at line 6266 of file InstructionCombining.cpp.

References llvm::dbgs(), DL, F, llvm::getInstCombineCLOptions(), LLVM_DEBUG, llvm::LowerDbgDeclare(), llvm::InstCombineOptions::MaxIterations, llvm::InstCombinerImpl::prepareWorklist(), llvm::reportFatalUsageError(), llvm::InstCombinerImpl::run(), and llvm::InstCombineOptions::VerifyFixpoint.

Referenced by llvm::InstCombinePass::run(), and llvm::InstructionCombiningPass::runOnFunction().

constantFoldBinOpWithSplat()

Constant * constantFoldBinOpWithSplat ( unsigned Opcode, Constant * Vector, Constant * Splat, bool SplatLHS, const DataLayout & DL )

static

Definition at line 2430 of file InstructionCombining.cpp.

References llvm::cast(), llvm::ConstantFoldBinaryOpOperands(), DL, llvm::ConstantVector::getSplat(), LHS, RHS, llvm::Splat, std::swap(), and llvm::Vector.

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

DEBUG_COUNTER()

DEBUG_COUNTER	(	VisitCounter	,
		"instcombine-visit"	,
		"Controls which instructions are visited"	)

References llvm::dyn_cast(), and I.

foldFrexpOfSelect()

Value * foldFrexpOfSelect ( ExtractValueInst & EV, IntrinsicInst * FrexpCall, SelectInst * SelectInst, InstCombiner::BuilderTy & Builder )

static

Definition at line 4726 of file InstructionCombining.cpp.

References Cond, llvm::Instruction::copyIRFlags(), llvm::frexp(), llvm::CallBase::getCalledFunction(), llvm::SelectInst::getCondition(), llvm::SelectInst::getFalseValue(), llvm::SelectInst::getTrueValue(), llvm::Value::hasOneUse(), llvm::PatternMatch::m_APFloat(), llvm::PatternMatch::match(), and llvm::APFloatBase::rmNearestTiesToEven.

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

foldGEPOfPhi()

Instruction * foldGEPOfPhi ( GetElementPtrInst & GEP, PHINode * PN, IRBuilderBase & Builder )

static

Definition at line 3245 of file InstructionCombining.cpp.

References llvm::PHINode::addIncoming(), assert(), llvm::cast(), llvm::dyn_cast(), E(), F, GEP, llvm::PHINode::getIncomingBlock(), llvm::User::getNumOperands(), llvm::User::getOperand(), llvm::GetElementPtrInst::getTypeAtIndex(), llvm::Value::hasOneUse(), I, llvm::Type::isStructTy(), llvm::User::op_begin(), llvm::User::op_end(), and llvm::User::operands().

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

foldOperationIntoSelectOperand()

Value * foldOperationIntoSelectOperand ( Instruction & I, SelectInst * SI, Value * NewOp, InstCombiner & IC )

static

Definition at line 1810 of file InstructionCombining.cpp.

References llvm::Instruction::dropUBImplyingAttrsAndMetadata(), I, llvm::InstCombiner::InsertNewInstBefore(), and llvm::User::replaceUsesOfWith().

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

foldSelectGEP()

Instruction * foldSelectGEP ( GetElementPtrInst & GEP, InstCombiner::BuilderTy & Builder )

static

Thread a GEP operation with constant indices through the constant true/false arms of a select.

Definition at line 2785 of file InstructionCombining.cpp.

References Cond, llvm::SelectInst::Create(), GEP, llvm::PatternMatch::m_Constant(), llvm::PatternMatch::m_Instruction(), llvm::PatternMatch::m_Select(), llvm::PatternMatch::m_Value(), and llvm::PatternMatch::match().

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

foldSpliceBinOp()

template<Intrinsic::ID SpliceID>

Instruction * foldSpliceBinOp ( BinaryOperator & Inst, InstCombiner::BuilderTy & Builder )

static

Definition at line 2442 of file InstructionCombining.cpp.

References llvm::Instruction::copyIRFlags(), llvm::CallInst::Create(), llvm::dyn_cast(), F, llvm::PoisonValue::get(), llvm::Instruction::getModule(), llvm::Value::getName(), llvm::BinaryOperator::getOpcode(), llvm::User::getOperand(), llvm::Intrinsic::getOrInsertDeclaration(), llvm::isSplatValue(), LHS, llvm::PatternMatch::m_Intrinsic(), llvm::MIPatternMatch::m_OneUse(), llvm::PatternMatch::m_Poison(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), llvm::Offset, RHS, llvm::V1, X, and Y.

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

getBinOpsForFactorization()

Instruction::BinaryOps getBinOpsForFactorization ( Instruction::BinaryOps TopOpcode, BinaryOperator * Op, Value *& LHS, Value *& RHS, BinaryOperator * OtherOp )

static

This function predicates factorization using distributive laws.

By default, it just returns the 'Op' inputs. But for special-cases like 'add(shl(X, 5), ...)', this function will have TopOpcode == Instruction::Add and Op = shl(X, 5). The 'shl' is treated as the more general 'mul X, 32' to allow more factorization opportunities.

Definition at line 719 of file InstructionCombining.cpp.

References assert(), C(), llvm::ConstantFoldBinaryInstruction(), llvm::BinaryOperator::getOpcode(), llvm::Instruction::isBitwiseLogicOp(), LHS, llvm::PatternMatch::m_ImmConstant(), llvm::PatternMatch::m_LShr(), llvm::PatternMatch::m_NonNegative(), llvm::PatternMatch::m_Shl(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), and RHS.

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

getIdentityValue()

Value * getIdentityValue ( Instruction::BinaryOps Opcode, Value * V )

static

This function returns identity value for given opcode, which can be used to factor patterns like (X * 2) + X ==> (X * 2) + (X * 1) ==> X * (2 + 1).

Definition at line 706 of file InstructionCombining.cpp.

References llvm::ConstantExpr::getBinOpIdentity(), and llvm::isa().

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

getMergedGEPNoWrapFlags()

GEPNoWrapFlags getMergedGEPNoWrapFlags ( GEPOperator & GEP1, GEPOperator & GEP2 )

static

Determine nowrap flags for (gep (gep p, x), y) to (gep p, (x + y)) transform.

Definition at line 2778 of file InstructionCombining.cpp.

References llvm::GEPOperator::getNoWrapFlags(), and llvm::GEPNoWrapFlags::intersectForOffsetAdd().

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

hasNoSignedWrap()

bool hasNoSignedWrap ( BinaryOperator & I )

static

Definition at line 377 of file InstructionCombining.cpp.

References llvm::dyn_cast(), and I.

Referenced by llvm::SDNode::print_details(), llvm::InstCombinerImpl::SimplifyAssociativeOrCommutative(), llvm::InstCombinerImpl::visitLShr(), and llvm::InstCombinerImpl::visitMul().

hasNoUnsignedWrap()

bool hasNoUnsignedWrap ( BinaryOperator & I )

static

Definition at line 372 of file InstructionCombining.cpp.

References llvm::dyn_cast(), and I.

Referenced by llvm::InstCombinerImpl::commonIDivTransforms(), computeKnownBitsFromCond(), computeKnownBitsFromICmpCond(), getSmallConstantTripCount(), llvm::ScalarEvolution::isKnownMultipleOf(), isTruePredicate(), llvm::SDNode::print_details(), llvm::InstCombinerImpl::SimplifyAssociativeOrCommutative(), llvm::InstCombinerImpl::visitAShr(), and llvm::InstCombinerImpl::visitLShr().

INITIALIZE_PASS_BEGIN()

INITIALIZE_PASS_BEGIN	(	InstructionCombiningPass	,
		"instcombine"	,
		"Combine redundant instructions"	,
		false	,
		false	)

References INITIALIZE_PASS_DEPENDENCY.

isAllocSiteRemovable()

std::optional< ModRefInfo > isAllocSiteRemovable ( Instruction * AI, SmallVectorImpl< Instruction * > & Users, const TargetLibraryInfo & TLI, bool KnowInit, unsigned MaxUsers )

static

Definition at line 3776 of file InstructionCombining.cpp.

References Access, assert(), llvm::cast(), llvm::dyn_cast(), llvm::SmallVectorTemplateCommon< T, typename >::empty(), llvm::getAllocationFamily(), llvm::getFreedOperand(), llvm::TargetLibraryInfo::getLibFunc(), llvm::User::getOperand(), llvm::LoadInst::getPointerOperand(), llvm::getReallocatedOperand(), llvm::TargetLibraryInfo::has(), I, II, llvm::ICmpInst::isEquality(), llvm::isModSet(), isNeverEqualToUnescapedAlloc(), llvm::isRefSet(), isRemovableWrite(), llvm::LoadInst::isVolatile(), llvm_unreachable, llvm::PatternMatch::m_APInt(), llvm::PatternMatch::match(), MI, llvm::Mod, llvm::ModRef, llvm::NoModRef, llvm::SmallVectorImpl< T >::pop_back_val(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::Ref, Size, Users, and llvm::Instruction::users().

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

isCatchAll()

bool isCatchAll ( EHPersonality Personality, Constant * TypeInfo )

static

Return 'true' if the given typeinfo will match anything.

Definition at line 4899 of file InstructionCombining.cpp.

References llvm::CoreCLR, llvm::GNU_Ada, llvm::GNU_C, llvm::GNU_C_SjLj, llvm::GNU_CXX, llvm::GNU_CXX_SjLj, llvm::GNU_ObjC, llvm::isa(), llvm_unreachable, llvm::MSVC_CXX, llvm::MSVC_TableSEH, llvm::MSVC_X86SEH, llvm::Rust, llvm::Unknown, llvm::Wasm_CXX, llvm::Wasm_D, llvm::XL_CXX, and llvm::ZOS_CXX.

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

isNeverEqualToUnescapedAlloc()

bool isNeverEqualToUnescapedAlloc ( Value * V, const TargetLibraryInfo & TLI, Instruction * AI )

static

Definition at line 3743 of file InstructionCombining.cpp.

References llvm::dyn_cast(), llvm::isa(), and llvm::isAllocLikeFn().

Referenced by isAllocSiteRemovable().

isRemovableWrite()

bool isRemovableWrite ( CallBase & CB, Value * UsedV, const TargetLibraryInfo & TLI )

static

Given a call CB which uses an address UsedV, return true if we can prove the call's only possible effect is storing to V.

Definition at line 3755 of file InstructionCombining.cpp.

References llvm::CallBase::doesNotThrow(), llvm::MemoryLocation::getForDest(), llvm::Instruction::isTerminator(), llvm::Value::use_empty(), and llvm::Instruction::willReturn().

Referenced by isAllocSiteRemovable().

isUsedWithinShuffleVector()

bool isUsedWithinShuffleVector ( Value * V )

static

Definition at line 5427 of file InstructionCombining.cpp.

References llvm::isa(), isUsedWithinShuffleVector(), llvm::PatternMatch::m_BitCast(), llvm::PatternMatch::m_Specific(), and llvm::PatternMatch::match().

Referenced by isUsedWithinShuffleVector(), and llvm::InstCombinerImpl::visitFreeze().

leftDistributesOverRight()

bool leftDistributesOverRight ( Instruction::BinaryOps LOp, Instruction::BinaryOps ROp )

static

Return whether "X LOp (Y ROp Z)" is always equal to "(X LOp Y) ROp (X LOp Z)".

Definition at line 670 of file InstructionCombining.cpp.

maintainNoSignedWrap()

bool maintainNoSignedWrap ( BinaryOperator & I, Value * B, Value * C )

static

Definition at line 344 of file InstructionCombining.cpp.

References B(), C(), llvm::dyn_cast(), I, llvm::PatternMatch::m_APInt(), llvm::PatternMatch::match(), llvm::APInt::sadd_ov(), llvm::APInt::smul_ov(), and llvm::APInt::ssub_ov().

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

matchSymmetricPhiNodesPair()

std::optional< std::pair< Value *, Value * > > matchSymmetricPhiNodesPair ( PHINode * LHS, PHINode * RHS )

static

Definition at line 1290 of file InstructionCombining.cpp.

References E(), llvm::equal(), I, LHS, and RHS.

rightDistributesOverLeft()

bool rightDistributesOverLeft ( Instruction::BinaryOps LOp, Instruction::BinaryOps ROp )

static

Return whether "(X LOp Y) ROp Z" is always equal to "(X ROp Z) LOp (Y ROp Z)".

Definition at line 691 of file InstructionCombining.cpp.

References llvm::Instruction::isBitwiseLogicOp(), llvm::Instruction::isCommutative(), llvm::Instruction::isShift(), and leftDistributesOverRight().

shorter_filter()

bool shorter_filter ( const Value * LHS, const Value * RHS )

static

Definition at line 4929 of file InstructionCombining.cpp.

References llvm::cast(), LHS, and RHS.

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

shouldCanonicalizeGEPToPtrAdd()

bool shouldCanonicalizeGEPToPtrAdd ( GetElementPtrInst & GEP )

static

Return true if we should canonicalize the gep to an i8 ptradd.

Definition at line 3216 of file InstructionCombining.cpp.

References llvm::any_of(), llvm::dyn_cast(), GEP, llvm::Type::isIntegerTy(), llvm::Type::isScalableTy(), llvm::PatternMatchHelpers::m_CombineOr(), llvm::PatternMatch::m_ConstantInt(), llvm::PatternMatch::m_Mul(), llvm::MIPatternMatch::m_OneUse(), llvm::PatternMatch::m_Shl(), llvm::PatternMatch::m_Value(), and llvm::PatternMatch::match().

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

shouldMergeGEPs()

bool shouldMergeGEPs ( GEPOperator & GEP, GEPOperator & Src )

static

Definition at line 2371 of file InstructionCombining.cpp.

References GEP.

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

simplifyAssocCastAssoc()

bool simplifyAssocCastAssoc ( BinaryOperator * BinOp1, InstCombinerImpl & IC )

static

Combine constant operands of associative operations either before or after a cast to eliminate one of the associative operations: (op (cast (op X, C2)), C1) --> (cast (op X, op (C1, C2))) (op (cast (op X, C2)), C1) --> (op (cast X), op (C1, C2))

Definition at line 386 of file InstructionCombining.cpp.

References llvm::ConstantFoldBinaryOpOperands(), llvm::ConstantFoldCastOperand(), DL, llvm::Instruction::dropPoisonGeneratingFlags(), llvm::dyn_cast(), llvm::InstCombiner::getDataLayout(), llvm::BinaryOperator::getOpcode(), llvm::User::getOperand(), llvm::Value::getType(), llvm::Instruction::isBitwiseLogicOp(), llvm::PatternMatch::m_Constant(), llvm::PatternMatch::match(), and llvm::InstCombiner::replaceOperand().

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

simplifyInstructionWithPHI()

Value * simplifyInstructionWithPHI ( Instruction & I, PHINode * PN, Value * InValue, BasicBlock * InBB, const DataLayout & DL, const SimplifyQuery SQ )

static

Definition at line 1885 of file InstructionCombining.cpp.

References AbstractManglingParser< Derived, Alloc >::Ops, DL, llvm::dyn_cast(), llvm::ConstantInt::getBool(), llvm::ICmpInst::getCmpPredicate(), llvm::CondBrInst::getCondition(), llvm::ilist_detail::node_parent_access< NodeTy, ParentTy >::getParent(), llvm::CondBrInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::SimplifyQuery::getWithInstruction(), I, llvm::isImpliedCondition(), llvm::PatternMatch::m_ConstantExpr(), llvm::PatternMatch::match(), and llvm::simplifyInstructionWithOperands().

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

simplifyOperationIntoSelectOperand()

Value * simplifyOperationIntoSelectOperand ( Instruction & I, SelectInst * SI, bool IsTrueArm )

static

Definition at line 1785 of file InstructionCombining.cpp.

References AbstractManglingParser< Derived, Alloc >::Ops, llvm::Constant::getNullValue(), I, llvm::CmpInst::ICMP_EQ, llvm::CmpInst::ICMP_NE, llvm::isGuaranteedNotToBeUndefOrPoison(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_SpecificICmp(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::m_ZExt(), llvm::PatternMatch::match(), and llvm::simplifyInstructionWithOperands().

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

simplifySwitchOnSelectUsingRanges()

Value * simplifySwitchOnSelectUsingRanges ( SwitchInst & SI, SelectInst * Select, bool IsTrueArm )

static

Definition at line 4476 of file InstructionCombining.cpp.

References C(), llvm::ConstantRange::contains(), llvm::dyn_cast(), llvm::CmpInst::getInversePredicate(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_ICmp(), llvm::PatternMatch::m_Specific(), llvm::ConstantRange::makeExactICmpRegion(), llvm::PatternMatch::match(), Select, and X.

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

SoleWriteToDeadLocal()

bool SoleWriteToDeadLocal ( Instruction * I, TargetLibraryInfo & TLI )

static

Check for case where the call writes to an otherwise dead alloca.

This shows up for unused out-params in idiomatic C/C++ code. Note that this helper only analyzes the write; doesn't check any other legality aspect.

Definition at line 5556 of file InstructionCombining.cpp.

References llvm::cast(), llvm::dyn_cast(), llvm::SmallVectorTemplateCommon< T, typename >::empty(), llvm::MemoryLocation::getForDest(), llvm::getUnderlyingObject(), I, llvm::SmallPtrSetImpl< PtrType >::insert(), llvm::isa(), llvm::SmallVectorImpl< T >::pop_back_val(), and llvm::SmallVectorTemplateBase< T, bool >::push_back().

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

STATISTIC() [1/12]

STATISTIC	(	NumCombined	,
		"Number of insts combined"	)

STATISTIC() [2/12]

STATISTIC	(	NumConstProp	,
		"Number of constant folds"	)

STATISTIC() [3/12]

STATISTIC	(	NumDeadInst	,
		"Number of dead inst eliminated"	)

STATISTIC() [4/12]

STATISTIC	(	NumExpand	,
		"Number of expansions"	)

STATISTIC() [5/12]

STATISTIC	(	NumFactor	,
		"Number of factorizations"	)

STATISTIC() [6/12]

STATISTIC	(	NumFourOrMoreIterations	,
		"Number of functions with four or more iterations"	)

STATISTIC() [7/12]

STATISTIC	(	NumOneIteration	,
		"Number of functions with one iteration"	)

STATISTIC() [8/12]

STATISTIC	(	NumReassoc	,
		"Number of reassociations"	)

STATISTIC() [9/12]

STATISTIC	(	NumSunkInst	,
		"Number of instructions sunk"	)

STATISTIC() [10/12]

STATISTIC	(	NumThreeIterations	,
		"Number of functions with three iterations"	)

STATISTIC() [11/12]

STATISTIC	(	NumTwoIterations	,
		"Number of functions with two iterations"	)

STATISTIC() [12/12]

STATISTIC	(	NumWorklistIterations	,
		"Number of instruction combining iterations performed"	)

tryFactorization()

Value * tryFactorization ( BinaryOperator & I, const SimplifyQuery & SQ, InstCombiner::BuilderTy & Builder, Instruction::BinaryOps InnerOpcode, Value * A, Value * B, Value * C, Value * D )

static

This tries to simplify binary operations by factorizing out common terms (e.

g. "(A*B)+(A*C)" -> "A*(B+C)").

Definition at line 747 of file InstructionCombining.cpp.

References A(), assert(), B(), C(), llvm::cast(), D(), llvm::dyn_cast(), llvm::SimplifyQuery::getWithInstruction(), I, llvm::isa(), llvm::Instruction::isCommutative(), llvm::APInt::isMinSignedValue(), leftDistributesOverRight(), LHS, llvm::PatternMatch::m_APInt(), llvm::PatternMatch::match(), RHS, rightDistributesOverLeft(), llvm::simplifyBinOp(), std::swap(), and llvm::Value::takeName().

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

tryToMoveFreeBeforeNullTest()

Instruction * tryToMoveFreeBeforeNullTest ( CallInst & FI, const DataLayout & DL )

static

Move the call to free before a NULL test.

Check if this free is accessed after its argument has been test against NULL (property 0). If yes, it is legal to move this call in its predecessor block.

The move is performed only if the block containing the call to free will be removed, i.e.:

1. it has only one predecessor P, and P has two successors
2. it contains the call, noops, and an unconditional branch
3. its successor is the same as its predecessor's successor

The profitability is out-of concern here and this function should be called only if the caller knows this transformation would be profitable (e.g., for code size).

Definition at line 4095 of file InstructionCombining.cpp.

References assert(), DL, llvm::dyn_cast(), llvm::CallBase::getArgOperand(), llvm::CallBase::getAttributes(), llvm::Value::getContext(), llvm::Attribute::getDereferenceableBytes(), llvm::ilist_node_impl< OptionsT >::getIterator(), llvm::ilist_detail::node_parent_access< NodeTy, ParentTy >::getParent(), llvm::BasicBlock::getSinglePredecessor(), llvm::BasicBlock::getTerminator(), llvm::CmpInst::ICMP_EQ, llvm::CmpInst::ICMP_NE, llvm::isa(), llvm::Attribute::isValid(), llvm::PatternMatch::m_Br(), llvm::PatternMatchHelpers::m_CombineOr(), llvm::PatternMatch::m_ICmp(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_UnconditionalBr(), llvm::PatternMatch::m_Zero(), llvm::make_early_inc_range(), llvm::PatternMatch::match(), llvm::CallBase::setAttributes(), llvm::BasicBlock::size(), and uint64_t.

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

Variable Documentation

false

Combine redundant false

Definition at line 6438 of file InstructionCombining.cpp.

instcombine

instcombine

Definition at line 6437 of file InstructionCombining.cpp.

instructions

Combine redundant instructions

Definition at line 6438 of file InstructionCombining.cpp.