InstCombineCalls.cpp File Reference

#include "InstCombineInternal.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLFunctionalExtras.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumeBundleQueries.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Analysis/VectorUtils.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/InlineAsm.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/IntrinsicsAArch64.h"
#include "llvm/IR/IntrinsicsAMDGPU.h"
#include "llvm/IR/IntrinsicsARM.h"
#include "llvm/IR/IntrinsicsHexagon.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/Statepoint.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Support/AtomicOrdering.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/InstCombine/InstCombiner.h"
#include "llvm/Transforms/Utils/AssumeBundleBuilder.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <optional>
#include <utility>
#include <vector>
#include "llvm/Transforms/Utils/InstructionWorklist.h"

Go to the source code of this file.

Namespaces
namespace	llvm
	This is an optimization pass for GlobalISel generic memory operations.

Macros
#define	DEBUG_TYPE   "instcombine"

Functions
	STATISTIC (NumSimplified, "Number of library calls simplified")
static Type *	getPromotedType (Type *Ty)
	Return the specified type promoted as it would be to pass though a va_arg area.
static bool	hasUndefSource (AnyMemTransferInst *MI)
	Recognize a memcpy/memmove from a trivially otherwise unused alloca.
static Instruction *	simplifyInvariantGroupIntrinsic (IntrinsicInst &II, InstCombinerImpl &IC)
	This function transforms launder.invariant.group and strip.invariant.group like: launder(launder(x)) -> launder(x) (the result is not the argument) launder(strip(x)) -> launder(x) strip(strip(x)) -> strip(x) (the result is not the argument) strip(launder(x)) -> strip(x) This is legal because it preserves the most recent information about the presence or absence of invariant.group.
static Instruction *	foldCttzCtlz (IntrinsicInst &II, InstCombinerImpl &IC)
static Instruction *	foldCtpop (IntrinsicInst &II, InstCombinerImpl &IC)
static Value *	simplifyNeonTbl1 (const IntrinsicInst &II, InstCombiner::BuilderTy &Builder)
	Convert a table lookup to shufflevector if the mask is constant.
static bool	haveSameOperands (const IntrinsicInst &I, const IntrinsicInst &E, unsigned NumOperands)
static bool	removeTriviallyEmptyRange (IntrinsicInst &EndI, InstCombinerImpl &IC, std::function< bool(const IntrinsicInst &)> IsStart)
static CallInst *	canonicalizeConstantArg0ToArg1 (CallInst &Call)
static Instruction *	createOverflowTuple (IntrinsicInst *II, Value *Result, Constant *Overflow)
	Creates a result tuple for an overflow intrinsic II with a given Result and a constant Overflow value.
static bool	fpclassTestIsFCmp0 (FPClassTest Mask, const Function &F, Type *Ty)
static std::optional< bool >	getKnownSign (Value *Op, Instruction *CxtI, const DataLayout &DL, AssumptionCache *AC, DominatorTree *DT)
static Instruction *	moveAddAfterMinMax (IntrinsicInst *II, InstCombiner::BuilderTy &Builder)
	Try to canonicalize min/max(X + C0, C1) as min/max(X, C1 - C0) + C0.
static Instruction *	foldClampRangeOfTwo (IntrinsicInst *II, InstCombiner::BuilderTy &Builder)
	If we have a clamp pattern like max (min X, 42), 41 – where the output can only be one of two possible constant values – turn that into a select of constants.
static Value *	reassociateMinMaxWithConstants (IntrinsicInst *II, IRBuilderBase &Builder)
	If this min/max has a constant operand and an operand that is a matching min/max with a constant operand, constant-fold the 2 constant operands.
static Instruction *	reassociateMinMaxWithConstantInOperand (IntrinsicInst *II, InstCombiner::BuilderTy &Builder)
	If this min/max has a matching min/max operand with a constant, try to push the constant operand into this instruction.
static Instruction *	factorizeMinMaxTree (IntrinsicInst *II)
	Reduce a sequence of min/max intrinsics with a common operand.
static Instruction *	foldShuffledIntrinsicOperands (IntrinsicInst *II, InstCombiner::BuilderTy &Builder)
	If all arguments of the intrinsic are unary shuffles with the same mask, try to shuffle after the intrinsic.
static bool	isSafeToEliminateVarargsCast (const CallBase &Call, const DataLayout &DL, const CastInst *const CI, const int ix)
	If this cast does not affect the value passed through the varargs area, we can eliminate the use of the cast.
static IntrinsicInst *	findInitTrampolineFromAlloca (Value *TrampMem)
static IntrinsicInst *	findInitTrampolineFromBB (IntrinsicInst *AdjustTramp, Value *TrampMem)
static IntrinsicInst *	findInitTrampoline (Value *Callee)

Variables
static cl::opt< unsigned >	GuardWideningWindow ("instcombine-guard-widening-window", cl::init(3), cl::desc("How wide an instruction window to bypass looking for " "another guard"))

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "instcombine"

Definition at line 77 of file InstCombineCalls.cpp.

Function Documentation

canonicalizeConstantArg0ToArg1()

static CallInst * canonicalizeConstantArg0ToArg1 ( CallInst &  Call )

static

Definition at line 784 of file InstCombineCalls.cpp.

References assert().

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

createOverflowTuple()

static Instruction * createOverflowTuple ( IntrinsicInst *  II, Value *  Result, Constant *  Overflow  )

static

Creates a result tuple for an overflow intrinsic II with a given Result and a constant Overflow value.

Definition at line 797 of file InstCombineCalls.cpp.

References llvm::InsertValueInst::Create(), llvm::ConstantStruct::get(), llvm::PoisonValue::get(), llvm::Value::getType(), and Struct.

factorizeMinMaxTree()

static Instruction * factorizeMinMaxTree ( IntrinsicInst *  II )

static

Reduce a sequence of min/max intrinsics with a common operand.

Definition at line 1169 of file InstCombineCalls.cpp.

References A, assert(), B, llvm::CallingConv::C, llvm::CallInst::Create(), D, llvm::CallBase::getArgOperand(), llvm::Intrinsic::getDeclaration(), llvm::IntrinsicInst::getIntrinsicID(), llvm::Instruction::getModule(), llvm::Value::getType(), llvm::Value::hasOneUse(), LHS, llvm::Mod, and RHS.

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

findInitTrampoline()

static IntrinsicInst * findInitTrampoline ( Value *  Callee )

static

Definition at line 3257 of file InstCombineCalls.cpp.

References Callee, findInitTrampolineFromAlloca(), findInitTrampolineFromBB(), llvm::IntrinsicInst::getIntrinsicID(), llvm::User::getOperand(), and IT.

findInitTrampolineFromAlloca()

static IntrinsicInst * findInitTrampolineFromAlloca ( Value *  TrampMem )

static

Definition at line 3197 of file InstCombineCalls.cpp.

References llvm::IntrinsicInst::getIntrinsicID(), llvm::User::getOperand(), llvm::Value::stripPointerCasts(), and llvm::Value::users().

Referenced by findInitTrampoline().

findInitTrampolineFromBB()

static IntrinsicInst * findInitTrampolineFromBB ( IntrinsicInst *  AdjustTramp, Value *  TrampMem  )

static

Definition at line 3236 of file InstCombineCalls.cpp.

References llvm::BasicBlock::begin(), E, llvm::IntrinsicInst::getIntrinsicID(), llvm::ilist_node_impl< OptionsT >::getIterator(), llvm::User::getOperand(), llvm::Instruction::getParent(), I, and llvm::Instruction::mayWriteToMemory().

Referenced by findInitTrampoline().

foldClampRangeOfTwo()

static Instruction * foldClampRangeOfTwo ( IntrinsicInst *  II, InstCombiner::BuilderTy &  Builder  )

static

If we have a clamp pattern like max (min X, 42), 41 – where the output can only be one of two possible constant values – turn that into a select of constants.

Definition at line 1078 of file InstCombineCalls.cpp.

References llvm::CmpInst::BAD_ICMP_PREDICATE, Builder, llvm::SelectInst::Create(), llvm::ConstantInt::get(), llvm::CallBase::getArgOperand(), llvm::IntrinsicInst::getIntrinsicID(), llvm::Value::getType(), llvm::Value::hasOneUse(), llvm::CmpInst::ICMP_SGT, llvm::CmpInst::ICMP_SLT, llvm::CmpInst::ICMP_UGT, llvm::CmpInst::ICMP_ULT, llvm_unreachable, llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_SMax(), llvm::PatternMatch::m_SMin(), llvm::PatternMatch::m_UMax(), llvm::PatternMatch::m_UMin(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), and X.

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

foldCtpop()

static Instruction * foldCtpop ( IntrinsicInst &  II, InstCombinerImpl &  IC  )

static

Definition at line 608 of file InstCombineCalls.cpp.

References assert(), llvm::BitWidth, llvm::InstCombiner::Builder, llvm::InstCombiner::computeKnownBits(), llvm::KnownBits::countMaxPopulation(), llvm::KnownBits::countMinPopulation(), llvm::CallInst::Create(), llvm::CastInst::Create(), llvm::IRBuilderBase::CreateCall(), llvm::IRBuilderBase::CreateICmp(), llvm::IRBuilderBase::CreateSub(), llvm::IRBuilderBase::CreateUnaryIntrinsic(), F, llvm::ConstantAsMetadata::get(), llvm::MDNode::get(), llvm::ConstantInt::get(), llvm::CallBase::getArgOperand(), llvm::Value::getContext(), llvm::Intrinsic::getDeclaration(), llvm::IRBuilderBase::getFalse(), llvm::IntrinsicInst::getIntrinsicID(), llvm::Instruction::getMetadata(), llvm::Instruction::getModule(), llvm::Constant::getNullValue(), llvm::Type::getScalarSizeInBits(), llvm::Type::getScalarType(), llvm::Value::getType(), llvm::Value::hasOneUse(), llvm::CmpInst::ICMP_NE, llvm::InstCombiner::isKnownToBeAPowerOfTwo(), IT, LowAndHigh, llvm::PatternMatch::m_Add(), llvm::PatternMatch::m_AllOnes(), llvm::PatternMatch::m_BitReverse(), llvm::PatternMatch::m_BSwap(), llvm::PatternMatch::m_c_And(), llvm::PatternMatch::m_c_Or(), llvm::PatternMatch::m_Deferred(), llvm::PatternMatch::m_FShl(), llvm::PatternMatch::m_FShr(), llvm::PatternMatch::m_Neg(), llvm::PatternMatch::m_Not(), llvm::PatternMatch::m_OneUse(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::m_ZExt(), llvm::PatternMatch::match(), llvm::InstCombiner::replaceInstUsesWith(), llvm::InstCombiner::replaceOperand(), llvm::Instruction::setMetadata(), X, Y, and llvm::KnownBits::Zero.

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

foldCttzCtlz()

static Instruction * foldCttzCtlz ( IntrinsicInst &  II, InstCombinerImpl &  IC  )

static

Definition at line 508 of file InstCombineCalls.cpp.

References assert(), llvm::InstCombiner::Builder, llvm::CallingConv::C, llvm::InstCombiner::computeKnownBits(), llvm::KnownBits::countMaxLeadingZeros(), llvm::KnownBits::countMaxTrailingZeros(), llvm::KnownBits::countMinLeadingZeros(), llvm::KnownBits::countMinTrailingZeros(), llvm::CallInst::Create(), llvm::IRBuilderBase::CreateBinaryIntrinsic(), llvm::BinaryOperator::CreateNot(), llvm::IRBuilderBase::CreateZExt(), F, llvm::SelectPatternResult::Flavor, llvm::ConstantAsMetadata::get(), llvm::MDNode::get(), llvm::ConstantInt::get(), llvm::CallBase::getArgOperand(), llvm::InstCombiner::getAssumptionCache(), llvm::Value::getContext(), llvm::InstCombiner::getDataLayout(), llvm::Intrinsic::getDeclaration(), llvm::InstCombiner::getDominatorTree(), llvm::IntrinsicInst::getIntrinsicID(), llvm::Instruction::getMetadata(), llvm::Instruction::getModule(), llvm::Constant::getNullValue(), llvm::Type::getScalarType(), llvm::IRBuilderBase::getTrue(), llvm::Value::getType(), llvm::Type::isIntOrIntVectorTy(), llvm::isKnownNonZero(), llvm::APInt::isZero(), IT, LowAndHigh, llvm::PatternMatch::m_BitReverse(), llvm::PatternMatch::m_Neg(), llvm::PatternMatch::m_One(), llvm::PatternMatch::m_OneUse(), llvm::PatternMatch::m_SExt(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::m_Zero(), llvm::PatternMatch::m_ZExt(), llvm::PatternMatch::match(), llvm::matchSelectPattern(), llvm::KnownBits::One, llvm::InstCombiner::replaceInstUsesWith(), llvm::InstCombiner::replaceOperand(), llvm::Instruction::setMetadata(), llvm::SPF_ABS, llvm::SPF_NABS, X, and Y.

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

foldShuffledIntrinsicOperands()

static Instruction * foldShuffledIntrinsicOperands ( IntrinsicInst *  II, InstCombiner::BuilderTy &  Builder  )

static

If all arguments of the intrinsic are unary shuffles with the same mask, try to shuffle after the intrinsic.

Definition at line 1228 of file InstCombineCalls.cpp.

References llvm::CallBase::arg_size(), llvm::CallBase::args(), Builder, llvm::CallBase::getArgOperand(), llvm::IntrinsicInst::getIntrinsicID(), llvm::PatternMatch::m_Shuffle(), llvm::PatternMatch::m_Undef(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), llvm::none_of(), and X.

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

fpclassTestIsFCmp0()

static bool fpclassTestIsFCmp0 ( FPClassTest  Mask, const Function &  F, Type *  Ty  )

static

Returns

true if the test performed by llvm.is.fpclass(x, Mask) is equivalent to fcmp oeq x, 0.0 with the floating-point environment assumed for F for type Ty

Definition at line 819 of file InstCombineCalls.cpp.

References F, llvm::fcSubnormal, llvm::fcZero, llvm::Type::getFltSemantics(), llvm::Type::getScalarType(), llvm::DenormalMode::IEEE, llvm::DenormalMode::PositiveZero, and llvm::DenormalMode::PreserveSign.

getKnownSign()

static std::optional< bool > getKnownSign ( Value *  Op, Instruction *  CxtI, const DataLayout &  DL, AssumptionCache *  AC, DominatorTree *  DT  )

static

Definition at line 958 of file InstCombineCalls.cpp.

References llvm::computeKnownBits(), DL, llvm::Constant::getNullValue(), llvm::CmpInst::ICMP_SLT, llvm::isImpliedByDomCondition(), llvm::KnownBits::isNegative(), llvm::KnownBits::isNonNegative(), llvm::PatternMatch::m_NSWSub(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), X, and Y.

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

getPromotedType()

static Type * getPromotedType ( Type *  Ty )

static

Return the specified type promoted as it would be to pass though a va_arg area.

Definition at line 99 of file InstCombineCalls.cpp.

References llvm::Type::getContext(), and llvm::Type::getInt32Ty().

hasUndefSource()

static bool hasUndefSource ( AnyMemTransferInst *  MI )

static

Recognize a memcpy/memmove from a trivially otherwise unused alloca.

TODO: This should probably be integrated with visitAllocSites, but that requires a deeper change to allow either unread or unwritten objects.

Definition at line 110 of file InstCombineCalls.cpp.

References MI.

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

haveSameOperands()

static bool haveSameOperands ( const IntrinsicInst &  I, const IntrinsicInst &  E, unsigned  NumOperands  )

static

Definition at line 729 of file InstCombineCalls.cpp.

References assert(), E, and I.

Referenced by removeTriviallyEmptyRange().

isSafeToEliminateVarargsCast()

static bool isSafeToEliminateVarargsCast ( const CallBase &  Call, const DataLayout &  DL, const CastInst *const  CI, const int  ix  )

static

If this cast does not affect the value passed through the varargs area, we can eliminate the use of the cast.

Definition at line 3131 of file InstCombineCalls.cpp.

References DL, llvm::User::getOperand(), llvm::Value::getType(), llvm::CastInst::isLosslessCast(), and llvm::Type::isSized().

moveAddAfterMinMax()

static Instruction * moveAddAfterMinMax ( IntrinsicInst *  II, InstCombiner::BuilderTy &  Builder  )

static

Try to canonicalize min/max(X + C0, C1) as min/max(X, C1 - C0) + C0.

This can trigger other combines.

Definition at line 977 of file InstCombineCalls.cpp.

References llvm::Add, assert(), Builder, llvm::ConstantInt::get(), llvm::CallBase::getArgOperand(), llvm::IntrinsicInst::getIntrinsicID(), llvm::Value::getType(), llvm::PatternMatch::m_Add(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_OneUse(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), llvm::APInt::ssub_ov(), llvm::APInt::usub_ov(), and X.

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

reassociateMinMaxWithConstantInOperand()

static Instruction * reassociateMinMaxWithConstantInOperand ( IntrinsicInst *  II, InstCombiner::BuilderTy &  Builder  )

static

If this min/max has a matching min/max operand with a constant, try to push the constant operand into this instruction.

This can enable more folds.

Definition at line 1141 of file InstCombineCalls.cpp.

References Builder, llvm::CallingConv::C, llvm::CallInst::Create(), llvm::Intrinsic::getDeclaration(), llvm::IntrinsicInst::getIntrinsicID(), llvm::Instruction::getModule(), llvm::Value::getType(), llvm::PatternMatch::m_c_MaxOrMin(), llvm::PatternMatch::m_CombineAnd(), llvm::PatternMatch::m_ImmConstant(), llvm::PatternMatch::m_Instruction(), llvm::PatternMatch::m_MaxOrMin(), llvm::PatternMatch::m_OneUse(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), llvm::Value::takeName(), X, and Y.

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

reassociateMinMaxWithConstants()

static Value * reassociateMinMaxWithConstants ( IntrinsicInst *  II, IRBuilderBase &  Builder  )

static

If this min/max has a constant operand and an operand that is a matching min/max with a constant operand, constant-fold the 2 constant operands.

Definition at line 1118 of file InstCombineCalls.cpp.

References Builder, llvm::CallBase::getArgOperand(), llvm::IntrinsicInst::getIntrinsicID(), llvm::MinMaxIntrinsic::getPredicate(), llvm::Value::getType(), LHS, llvm::PatternMatch::m_ImmConstant(), and llvm::PatternMatch::match().

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

removeTriviallyEmptyRange()

static bool removeTriviallyEmptyRange ( IntrinsicInst &  EndI, InstCombinerImpl &  IC, std::function< bool(const IntrinsicInst &)>  IsStart  )

static

Definition at line 749 of file InstCombineCalls.cpp.

References llvm::CallBase::arg_size(), llvm::InstCombinerImpl::eraseInstFromFunction(), llvm::IntrinsicInst::getIntrinsicID(), llvm::Instruction::getParent(), haveSameOperands(), I, and llvm::BasicBlock::rend().

Referenced by llvm::InstCombinerImpl::visitCallInst(), and llvm::InstCombinerImpl::visitVAEndInst().

simplifyInvariantGroupIntrinsic()

static Instruction * simplifyInvariantGroupIntrinsic ( IntrinsicInst &  II, InstCombinerImpl &  IC  )

static

This function transforms launder.invariant.group and strip.invariant.group like: launder(launder(x)) -> launder(x) (the result is not the argument) launder(strip(x)) -> launder(x) strip(strip(x)) -> strip(x) (the result is not the argument) strip(launder(x)) -> strip(x) This is legal because it preserves the most recent information about the presence or absence of invariant.group.

Definition at line 476 of file InstCombineCalls.cpp.

References Arg, llvm::InstCombiner::Builder, llvm::IRBuilderBase::CreateAddrSpaceCast(), llvm::IRBuilderBase::CreateBitCast(), llvm::IRBuilderBase::CreateLaunderInvariantGroup(), llvm::IRBuilderBase::CreateStripInvariantGroup(), llvm::CallBase::getArgOperand(), llvm::IntrinsicInst::getIntrinsicID(), llvm::Type::getPointerAddressSpace(), llvm::Value::getType(), Intr, and llvm_unreachable.

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

simplifyNeonTbl1()

static Value * simplifyNeonTbl1 ( const IntrinsicInst &  II, InstCombiner::BuilderTy &  Builder  )

static

Convert a table lookup to shufflevector if the mask is constant.

This could benefit tbl1 if the mask is { 7,6,5,4,3,2,1,0 }, in which case we could lower the shufflevector with rev64 instructions as it's actually a byte reverse.

Definition at line 693 of file InstCombineCalls.cpp.

References Builder, llvm::CallingConv::C, llvm::CallBase::getArgOperand(), llvm::Constant::getNullValue(), llvm::Value::getType(), and I.

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

STATISTIC()

STATISTIC	(	NumSimplified	,
		"Number of library calls simplified"
	)

Variable Documentation

GuardWideningWindow

cl::opt< unsigned > GuardWideningWindow("instcombine-guard-widening-window", cl::init(3), cl::desc("How wide an instruction window to bypass looking for " "another guard")) ( "instcombine-guard-widening-window"  , cl::init(3)  , cl::desc("How wide an instruction window to bypass looking for " "another guard")    )

static

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