SimplifyCFG.cpp File Reference

#include "llvm/Transforms/Utils/Local.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ConstantRange.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/NoFolder.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include <algorithm>
#include <map>
#include <set>

Include dependency graph for SimplifyCFG.cpp:

Go to the source code of this file.

Defines
#define	DEBUG_TYPE   "simplifycfg"
Functions
	STATISTIC (NumBitMaps,"Number of switch instructions turned into bitmaps")
	STATISTIC (NumLookupTables,"Number of switch instructions turned into lookup tables")
	STATISTIC (NumSinkCommons,"Number of common instructions sunk down to the end block")
	STATISTIC (NumSpeculations,"Number of speculative executed instructions")
static bool	SafeToMergeTerminators (TerminatorInst *SI1, TerminatorInst *SI2)
static bool	isProfitableToFoldUnconditional (BranchInst *SI1, BranchInst *SI2, Instruction *Cond, SmallVectorImpl< PHINode * > &PhiNodes)
static void	AddPredecessorToBlock (BasicBlock *Succ, BasicBlock *NewPred, BasicBlock *ExistPred)
static Value *	GetIfCondition (BasicBlock *BB, BasicBlock *&IfTrue, BasicBlock *&IfFalse)
static unsigned	ComputeSpeculationCost (const User *I)
static bool	DominatesMergePoint (Value *V, BasicBlock *BB, SmallPtrSet< Instruction *, 4 > *AggressiveInsts, unsigned &CostRemaining)
static ConstantInt *	GetConstantInt (Value *V, const DataLayout *TD)
static Value *	GatherConstantCompares (Value *V, std::vector< ConstantInt * > &Vals, Value *&Extra, const DataLayout *TD, bool isEQ, unsigned &UsedICmps)
static void	EraseTerminatorInstAndDCECond (TerminatorInst *TI)
static void	EliminateBlockCases (BasicBlock *BB, std::vector< ValueEqualityComparisonCase > &Cases)
static bool	ValuesOverlap (std::vector< ValueEqualityComparisonCase > &C1, std::vector< ValueEqualityComparisonCase > &C2)
static int	ConstantIntSortPredicate (const void *P1, const void *P2)
static bool	HasBranchWeights (const Instruction *I)
static void	GetBranchWeights (TerminatorInst *TI, SmallVectorImpl< uint64_t > &Weights)
static void	FitWeights (MutableArrayRef< uint64_t > Weights)
static bool	isSafeToHoistInvoke (BasicBlock *BB1, BasicBlock *BB2, Instruction *I1, Instruction *I2)
static bool	HoistThenElseCodeToIf (BranchInst *BI)
static bool	SinkThenElseCodeToEnd (BranchInst *BI1)
static Value *	isSafeToSpeculateStore (Instruction *I, BasicBlock *BrBB, BasicBlock *StoreBB, BasicBlock *EndBB)
	Determine if we can hoist sink a sole store instruction out of a conditional block.
static bool	SpeculativelyExecuteBB (BranchInst *BI, BasicBlock *ThenBB)
	Speculate a conditional basic block flattening the CFG.
static bool	BlockIsSimpleEnoughToThreadThrough (BasicBlock *BB)
static bool	FoldCondBranchOnPHI (BranchInst *BI, const DataLayout *TD)
static bool	FoldTwoEntryPHINode (PHINode *PN, const DataLayout *TD)
static bool	SimplifyCondBranchToTwoReturns (BranchInst *BI, IRBuilder<> &Builder)
static bool	ExtractBranchMetadata (BranchInst *BI, uint64_t &ProbTrue, uint64_t &ProbFalse)
static bool	checkCSEInPredecessor (Instruction *Inst, BasicBlock *PB)
static bool	SimplifyCondBranchToCondBranch (BranchInst *PBI, BranchInst *BI)
static bool	SimplifyTerminatorOnSelect (TerminatorInst *OldTerm, Value *Cond, BasicBlock *TrueBB, BasicBlock *FalseBB, uint32_t TrueWeight, uint32_t FalseWeight)
static bool	SimplifySwitchOnSelect (SwitchInst *SI, SelectInst *Select)
static bool	SimplifyIndirectBrOnSelect (IndirectBrInst *IBI, SelectInst *SI)
static bool	TryToSimplifyUncondBranchWithICmpInIt (ICmpInst *ICI, IRBuilder<> &Builder, const TargetTransformInfo &TTI, const DataLayout *TD)
static bool	SimplifyBranchOnICmpChain (BranchInst *BI, const DataLayout *TD, IRBuilder<> &Builder)
static bool	TurnSwitchRangeIntoICmp (SwitchInst *SI, IRBuilder<> &Builder)
static bool	EliminateDeadSwitchCases (SwitchInst *SI)
static PHINode *	FindPHIForConditionForwarding (ConstantInt *CaseValue, BasicBlock *BB, int *PhiIndex)
static bool	ForwardSwitchConditionToPHI (SwitchInst *SI)
static bool	ValidLookupTableConstant (Constant *C)
static Constant *	LookupConstant (Value *V, const SmallDenseMap< Value *, Constant * > &ConstantPool)
static Constant *	ConstantFold (Instruction *I, const SmallDenseMap< Value *, Constant * > &ConstantPool)
static bool	GetCaseResults (SwitchInst *SI, ConstantInt *CaseVal, BasicBlock *CaseDest, BasicBlock **CommonDest, SmallVector< std::pair< PHINode *, Constant * >, 4 > &Res)
static bool	ShouldBuildLookupTable (SwitchInst *SI, uint64_t TableSize, const TargetTransformInfo &TTI, const DataLayout *TD, const SmallDenseMap< PHINode *, Type * > &ResultTypes)
static bool	SwitchToLookupTable (SwitchInst *SI, IRBuilder<> &Builder, const TargetTransformInfo &TTI, const DataLayout *TD)
static bool	passingValueIsAlwaysUndefined (Value *V, Instruction *I)
	Check if passing a value to an instruction will cause undefined behavior.
static bool	removeUndefIntroducingPredecessor (BasicBlock *BB)
Variables
static cl::opt< unsigned >	PHINodeFoldingThreshold ("phi-node-folding-threshold", cl::Hidden, cl::init(1), cl::desc("Control the amount of phi node folding to perform (default = 1)"))
static cl::opt< bool >	DupRet ("simplifycfg-dup-ret", cl::Hidden, cl::init(false), cl::desc("Duplicate return instructions into unconditional branches"))
static cl::opt< bool >	SinkCommon ("simplifycfg-sink-common", cl::Hidden, cl::init(true), cl::desc("Sink common instructions down to the end block"))
static cl::opt< bool >	HoistCondStores ("simplifycfg-hoist-cond-stores", cl::Hidden, cl::init(true), cl::desc("Hoist conditional stores if an unconditional store preceeds"))

---

Define Documentation

#define DEBUG_TYPE   "simplifycfg"

Definition at line 14 of file SimplifyCFG.cpp.

---

Function Documentation

static void AddPredecessorToBlock	(	BasicBlock *	Succ,
		BasicBlock *	NewPred,
		BasicBlock *	ExistPred
	)		[static]

AddPredecessorToBlock - Update PHI nodes in Succ to indicate that there will now be entries in it from the 'NewPred' block. The values that will be flowing into the PHI nodes will be the same as those coming in from ExistPred, an existing predecessor of Succ.

Definition at line 187 of file SimplifyCFG.cpp.

References llvm::PHINode::addIncoming(), llvm::BasicBlock::begin(), llvm::dyn_cast(), llvm::PHINode::getIncomingValueForBlock(), and I.

Referenced by llvm::FoldBranchToCommonDest(), FoldCondBranchOnPHI(), HoistThenElseCodeToIf(), SimplifyBranchOnICmpChain(), and SimplifyCondBranchToCondBranch().

static bool BlockIsSimpleEnoughToThreadThrough

(

BasicBlock *

BB

)

[static]

BlockIsSimpleEnoughToThreadThrough - Return true if we can thread a branch across this block.

Definition at line 1603 of file SimplifyCFG.cpp.

References llvm::BasicBlock::begin(), llvm::Instruction::getParent(), and llvm::BasicBlock::getTerminator().

Referenced by FoldCondBranchOnPHI(), and SimplifyCondBranchToCondBranch().

static bool checkCSEInPredecessor	(	Instruction *	Inst,
		BasicBlock *	PB
	)		[static]

checkCSEInPredecessor - Return true if the given instruction is available in its predecessor block. If yes, the instruction will be removed.

Definition at line 1970 of file SimplifyCFG.cpp.

References llvm::BasicBlock::begin(), llvm::BasicBlock::end(), llvm::Instruction::eraseFromParent(), I, llvm::Instruction::isIdenticalTo(), and llvm::Value::replaceAllUsesWith().

Referenced by llvm::FoldBranchToCommonDest().

static unsigned ComputeSpeculationCost

(

const User *

I

)

[static]

ComputeSpeculuationCost - Compute an abstract "cost" of speculating the given instruction, which is assumed to be safe to speculate. 1 means cheap, 2 means less cheap, and UINT_MAX means prohibitively expensive.

Definition at line 287 of file SimplifyCFG.cpp.

References llvm::APIntOps::And(), llvm::Call, llvm::Operator::getOpcode(), llvm::ICmp, llvm::isSafeToSpeculativelyExecute(), llvm::SPII::Load, llvm::LShr, llvm::APIntOps::Or(), llvm::Select, llvm::SExt, llvm::Trunc, and llvm::APIntOps::Xor().

Referenced by DominatesMergePoint(), and SpeculativelyExecuteBB().

static Constant* ConstantFold	(	Instruction *	I,
		const SmallDenseMap< Value *, Constant * > &	ConstantPool
	)		[static]

ConstantFold - Try to fold instruction I into a constant. This works for simple instructions such as binary operations where both operands are constant or can be replaced by constants from the ConstantPool. Returns the resulting constant on success, 0 otherwise.

Definition at line 3348 of file SimplifyCFG.cpp.

References llvm::ARM_PROC::A, llvm::ISD::ConstantPool, llvm::ConstantExpr::get(), llvm::ConstantExpr::getCast(), llvm::ConstantExpr::getCompare(), llvm::User::getOperand(), llvm::Constant::isAllOnesValue(), llvm::Constant::isNullValue(), LookupConstant(), and llvm::Select.

Referenced by GetCaseResults().

static int ConstantIntSortPredicate	(	const void *	P1,
		const void *	P2
	)		[static]

Definition at line 766 of file SimplifyCFG.cpp.

References llvm::ConstantInt::getValue(), and llvm::APInt::ult().

Referenced by SimplifyBranchOnICmpChain(), and TurnSwitchRangeIntoICmp().

static bool DominatesMergePoint	(	Value *	V,
		BasicBlock *	BB,
		SmallPtrSet< Instruction *, 4 > *	AggressiveInsts,
		unsigned &	CostRemaining
	)		[static]

DominatesMergePoint - If we have a merge point of an "if condition" as accepted above, return true if the specified value dominates the block. We don't handle the true generality of domination here, just a special case which works well enough for us.

If AggressiveInsts is non-null, and if V does not dominate BB, we check to see if V (which must be an instruction) and its recursive operands that do not dominate BB have a combined cost lower than CostRemaining and are non-trapping. If both are true, the instruction is inserted into the set and true is returned.

The cost for most non-trapping instructions is defined as 1 except for Select whose cost is 2.

After this function returns, CostRemaining is decreased by the cost of V plus its non-dominating operands. If that cost is greater than CostRemaining, false is returned and CostRemaining is undefined.

Definition at line 337 of file SimplifyCFG.cpp.

References llvm::CallingConv::C, ComputeSpeculationCost(), llvm::SmallPtrSet< PtrType, SmallSize >::count(), llvm::dyn_cast(), llvm::Instruction::getParent(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), I, llvm::SmallPtrSet< PtrType, SmallSize >::insert(), llvm::BranchInst::isConditional(), llvm::isSafeToSpeculativelyExecute(), llvm::User::op_begin(), and llvm::User::op_end().

Referenced by FoldTwoEntryPHINode().

static void EliminateBlockCases	(	BasicBlock *	BB,
		std::vector< ValueEqualityComparisonCase > &	Cases
	)		[static]

EliminateBlockCases - Given a vector of bb/value pairs, remove any entries in the list that match the specified block.

Definition at line 574 of file SimplifyCFG.cpp.

References llvm::LibFunc::remove.

static bool EliminateDeadSwitchCases

(

SwitchInst *

SI

)

[static]

EliminateDeadSwitchCases - Compute masked bits for the condition of a switch and use it to remove dead cases.

Definition at line 3203 of file SimplifyCFG.cpp.

References llvm::SmallVectorTemplateCommon< T >::back(), llvm::SmallVectorTemplateCommon< T >::begin(), llvm::tgtok::Bits, llvm::SwitchInst::case_begin(), llvm::SwitchInst::case_default(), llvm::SwitchInst::case_end(), llvm::ComputeMaskedBits(), llvm::dbgs(), DEBUG, llvm::SmallVectorBase::empty(), llvm::SmallVectorTemplateCommon< T >::end(), llvm::SwitchInst::findCaseValue(), getBitWidth(), GetBranchWeights(), llvm::SwitchInst::CaseIteratorT< SwitchInstTy, ConstantIntTy, SubsetsItTy, BasicBlockTy >::getCaseIndex(), llvm::SwitchInst::CaseIteratorT< SwitchInstTy, ConstantIntTy, SubsetsItTy, BasicBlockTy >::getCaseSuccessor(), llvm::SwitchInst::getCondition(), llvm::BasicBlock::getContext(), llvm::SwitchInst::getNumCases(), llvm::Instruction::getParent(), llvm::Value::getType(), HasBranchWeights(), I, llvm::LLVMContext::MD_prof, llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::pop_back(), llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::SwitchInst::removeCase(), llvm::BasicBlock::removePredecessor(), llvm::Instruction::setMetadata(), llvm::SmallVectorTemplateCommon< T >::size(), and llvm::swap().

static void EraseTerminatorInstAndDCECond

(

TerminatorInst *

TI

)

[static]

Definition at line 508 of file SimplifyCFG.cpp.

References llvm::dyn_cast(), llvm::Instruction::eraseFromParent(), and llvm::RecursivelyDeleteTriviallyDeadInstructions().

Referenced by llvm::FoldBranchToCommonDest(), HoistThenElseCodeToIf(), SimplifyBranchOnICmpChain(), SimplifyCondBranchToTwoReturns(), and SimplifyTerminatorOnSelect().

static bool ExtractBranchMetadata	(	BranchInst *	BI,
		uint64_t &	ProbTrue,
		uint64_t &	ProbFalse
	)		[static]

ExtractBranchMetadata - Given a conditional BranchInstruction, retrieve the probabilities of the branch taking each edge. Fills in the two APInt parameters and return true, or returns false if no or invalid metadata was found.

Definition at line 1953 of file SimplifyCFG.cpp.

References llvm::dyn_cast(), llvm::Instruction::getMetadata(), llvm::ConstantInt::getValue(), llvm::APInt::getZExtValue(), llvm::BranchInst::isConditional(), and llvm::LLVMContext::MD_prof.

Referenced by llvm::FoldBranchToCommonDest(), and SimplifyCondBranchToCondBranch().

static PHINode* FindPHIForConditionForwarding	(	ConstantInt *	CaseValue,
		BasicBlock *	BB,
		int *	PhiIndex
	)		[static]

FindPHIForConditionForwarding - If BB would be eligible for simplification by TryToSimplifyUncondBranchFromEmptyBlock (i.e. it is empty and terminated by an unconditional branch), look at the phi node for BB in the successor block and see if the incoming value is equal to CaseValue. If so, return the phi node, and set PhiIndex to BB's index in the phi node.

Definition at line 3256 of file SimplifyCFG.cpp.

References llvm::BasicBlock::begin(), llvm::MCID::Branch, llvm::dyn_cast(), llvm::BasicBlock::getFirstNonPHIOrDbg(), llvm::BasicBlock::getSinglePredecessor(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::BranchInst::isUnconditional(), and llvm::PHI.

Referenced by ForwardSwitchConditionToPHI().

static void FitWeights

(

MutableArrayRef< uint64_t >

Weights

)

[static]

Sees if any of the weights are too big for a uint32_t, and halves all the weights if any are.

Definition at line 811 of file SimplifyCFG.cpp.

References llvm::ArrayRef< T >::size().

Referenced by llvm::FoldBranchToCommonDest(), and SimplifyCondBranchToCondBranch().

static bool FoldCondBranchOnPHI	(	BranchInst *	BI,
		const DataLayout *	TD
	)		[static]

FoldCondBranchOnPHI - If we have a conditional branch on a PHI node value that is defined in the same block as the branch and if any PHI entries are constants, thread edges corresponding to that entry to be branches to their ultimate destination.

Definition at line 1631 of file SimplifyCFG.cpp.

References AddPredecessorToBlock(), llvm::BasicBlock::begin(), BlockIsSimpleEnoughToThreadThrough(), llvm::BasicBlock::Create(), llvm::BranchInst::Create(), llvm::dyn_cast(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT >::end(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT >::find(), llvm::FoldSingleEntryPHINodes(), llvm::BranchInst::getCondition(), llvm::BasicBlock::getContext(), llvm::PHINode::getIncomingBlock(), llvm::PHINode::getIncomingValue(), llvm::PHINode::getIncomingValueForBlock(), llvm::BasicBlock::getInstList(), llvm::Value::getName(), llvm::PHINode::getNumIncomingValues(), llvm::TerminatorInst::getNumSuccessors(), llvm::Instruction::getParent(), llvm::BasicBlock::getParent(), llvm::TerminatorInst::getSuccessor(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::ConstantInt::getType(), llvm::ConstantInt::getZExtValue(), llvm::Value::hasOneUse(), llvm::Type::isIntegerTy(), N, llvm::User::op_begin(), llvm::User::op_end(), llvm::BasicBlock::removePredecessor(), llvm::Value::setName(), llvm::TerminatorInst::setSuccessor(), and llvm::SimplifyInstruction().

static bool FoldTwoEntryPHINode	(	PHINode *	PN,
		const DataLayout *	TD
	)		[static]

FoldTwoEntryPHINode - Given a BB that starts with the specified two-entry PHI node, see if we can eliminate it.

Definition at line 1727 of file SimplifyCFG.cpp.

References llvm::BasicBlock::begin(), llvm::SmallPtrSet< PtrType, SmallSize >::count(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateBr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateSelect(), llvm::dbgs(), DEBUG, DominatesMergePoint(), llvm::dyn_cast(), llvm::Instruction::eraseFromParent(), GetIfCondition(), llvm::PHINode::getIncomingBlock(), llvm::PHINode::getIncomingValue(), llvm::BasicBlock::getInstList(), llvm::Value::getName(), llvm::Instruction::getParent(), llvm::BasicBlock::getTerminator(), llvm::Value::getType(), I, llvm::Type::isIntegerTy(), llvm::A64CC::NV, PHINodeFoldingThreshold, llvm::pred_begin(), llvm::Value::replaceAllUsesWith(), llvm::IRBuilderBase::SetInsertPoint(), llvm::SimplifyInstruction(), and llvm::Value::takeName().

static bool ForwardSwitchConditionToPHI

(

SwitchInst *

SI

)

[static]

ForwardSwitchConditionToPHI - Try to forward the condition of a switch instruction to a phi node dominated by the switch, if that would mean that some of the destination blocks of the switch can be folded away. Returns true if a change is made.

Definition at line 3289 of file SimplifyCFG.cpp.

References llvm::SwitchInst::case_begin(), llvm::SwitchInst::case_end(), FindPHIForConditionForwarding(), llvm::SwitchInst::getCondition(), I, llvm::PHI, llvm::PHINode::setIncomingValue(), and llvm::SmallVectorTemplateCommon< T, typename >::size().

static Value* GatherConstantCompares	(	Value *	V,
		std::vector< ConstantInt * > &	Vals,
		Value *&	Extra,
		const DataLayout *	TD,
		bool	isEQ,
		unsigned &	UsedICmps
	)		[static]

GatherConstantCompares - Given a potentially 'or'd or 'and'd together collection of icmp eq/ne instructions that compare a value against a constant, return the value being compared, and stick the constant into the Values vector.

Definition at line 427 of file SimplifyCFG.cpp.

References llvm::APIntOps::And(), llvm::CallingConv::C, llvm::dyn_cast(), llvm::ConstantInt::get(), GetConstantInt(), llvm::Value::getContext(), llvm::ConstantRange::getLower(), llvm::Instruction::getOpcode(), llvm::User::getOperand(), llvm::ConstantRange::getSetSize(), llvm::ConstantRange::getUpper(), I, llvm::CmpInst::ICMP_EQ, llvm::CmpInst::ICMP_NE, llvm::ConstantRange::inverse(), llvm::ConstantRange::isEmptySet(), llvm::ConstantRange::makeICmpRegion(), llvm::APIntOps::Or(), and llvm::APInt::ugt().

Referenced by SimplifyBranchOnICmpChain().

static void GetBranchWeights	(	TerminatorInst *	TI,
		SmallVectorImpl< uint64_t > &	Weights
	)		[static]

Get Weights of a given TerminatorInst, the default weight is at the front of the vector. If TI is a conditional eq, we need to swap the branch-weight metadata.

Definition at line 788 of file SimplifyCFG.cpp.

References llvm::SmallVectorTemplateCommon< T >::back(), llvm::dyn_cast(), llvm::SmallVectorTemplateCommon< T >::front(), llvm::BranchInst::getCondition(), llvm::Instruction::getMetadata(), llvm::MDNode::getNumOperands(), llvm::MDNode::getOperand(), llvm::ConstantInt::getValue(), llvm::APInt::getZExtValue(), llvm::CmpInst::ICMP_EQ, llvm::LLVMContext::MD_prof, llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::SmallVectorTemplateCommon< T >::size(), and std::swap().

Referenced by EliminateDeadSwitchCases(), SimplifySwitchOnSelect(), TryToSimplifyUncondBranchWithICmpInIt(), and TurnSwitchRangeIntoICmp().

static bool GetCaseResults	(	SwitchInst *	SI,
		ConstantInt *	CaseVal,
		BasicBlock *	CaseDest,
		BasicBlock **	CommonDest,
		SmallVector< std::pair< PHINode *, Constant * >, 4 > &	Res
	)		[static]

GetCaseResults - Try to determine the resulting constant values in phi nodes at the common destination basic block, *CommonDest, for one of the case destionations CaseDest corresponding to value CaseVal (0 for the default case), of a switch instruction SI.

Definition at line 3395 of file SimplifyCFG.cpp.

References llvm::BasicBlock::begin(), llvm::CallingConv::C, ConstantFold(), llvm::ISD::ConstantPool, llvm::BasicBlock::end(), llvm::SwitchInst::getCondition(), llvm::Instruction::getParent(), I, llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, InlineBuckets, KeyInfoT >, KeyT, ValueT, KeyInfoT >::insert(), LookupConstant(), llvm::PHI, and ValidLookupTableConstant().

Referenced by SwitchToLookupTable().

static ConstantInt* GetConstantInt	(	Value *	V,
		const DataLayout *	TD
	)		[static]

GetConstantInt - Extract ConstantInt from value, looking through IntToPtr and PointerNullValue. Return NULL if value is not a constant int.

Definition at line 394 of file SimplifyCFG.cpp.

References llvm::dyn_cast(), llvm::ConstantInt::get(), llvm::ConstantExpr::getIntegerCast(), llvm::DataLayout::getIntPtrType(), llvm::Value::getType(), llvm::ConstantInt::getType(), llvm::IntToPtr, and llvm::Type::isPointerTy().

Referenced by GatherConstantCompares().

static Value* GetIfCondition	(	BasicBlock *	BB,
		BasicBlock *&	IfTrue,
		BasicBlock *&	IfFalse
	)		[static]

GetIfCondition - Given a basic block (BB) with two predecessors (and at least one PHI node in it), check to see if the merge at this block is due to an "if condition". If so, return the boolean condition that determines which entry into BB will be taken. Also, return by references the block that will be entered from if the condition is true, and the block that will be entered if the condition is false.

This does no checking to see if the true/false blocks have large or unsavory instructions in them.

Definition at line 207 of file SimplifyCFG.cpp.

References llvm::BasicBlock::begin(), llvm::dyn_cast(), llvm::BranchInst::getCondition(), llvm::PHINode::getIncomingBlock(), llvm::PHINode::getNumIncomingValues(), llvm::BasicBlock::getSinglePredecessor(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::BranchInst::isConditional(), and llvm::swap().

Referenced by FoldTwoEntryPHINode().

static bool HasBranchWeights

(

const Instruction *

I

)

[inline, static]

Definition at line 776 of file SimplifyCFG.cpp.

References llvm::Instruction::getMetadata(), llvm::MDNode::getOperand(), and llvm::LLVMContext::MD_prof.

Referenced by EliminateDeadSwitchCases(), SimplifySwitchOnSelect(), TryToSimplifyUncondBranchWithICmpInIt(), and TurnSwitchRangeIntoICmp().

static bool HoistThenElseCodeToIf

(

BranchInst *

BI

)

[static]

HoistThenElseCodeToIf - Given a conditional branch that goes to BB1 and BB2, hoist any common code in the two blocks up into the branch block. The caller of this function guarantees that BI's block dominates BB1 and BB2.

Definition at line 1060 of file SimplifyCFG.cpp.

References AddPredecessorToBlock(), llvm::BasicBlock::begin(), llvm::Instruction::clone(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateSelect(), llvm::dyn_cast(), EraseTerminatorInstAndDCECond(), llvm::BranchInst::getCondition(), llvm::PHINode::getIncomingBlock(), llvm::PHINode::getIncomingValueForBlock(), llvm::BasicBlock::getInstList(), llvm::Value::getName(), llvm::PHINode::getNumIncomingValues(), llvm::Instruction::getParent(), llvm::BranchInst::getSuccessor(), llvm::Value::getType(), llvm::Value::intersectOptionalDataWith(), llvm::Instruction::isIdenticalToWhenDefined(), isSafeToHoistInvoke(), llvm::Type::isVoidTy(), llvm::Value::replaceAllUsesWith(), llvm::PHINode::setIncomingValue(), llvm::succ_begin(), llvm::succ_end(), and llvm::Value::takeName().

static bool isProfitableToFoldUnconditional	(	BranchInst *	SI1,
		BranchInst *	SI2,
		Instruction *	Cond,
		SmallVectorImpl< PHINode * > &	PhiNodes
	)		[static]

isProfitableToFoldUnconditional - Return true if it is safe and profitable to merge these two terminator instructions together, where SI1 is an unconditional branch. PhiNodes will store all PHI nodes in common successors.

Definition at line 147 of file SimplifyCFG.cpp.

References llvm::SmallPtrSet< PtrType, SmallSize >::count(), llvm::dyn_cast(), llvm::BranchInst::getCondition(), llvm::PHINode::getIncomingValueForBlock(), llvm::User::getOperand(), llvm::Instruction::getParent(), I, llvm::BranchInst::isConditional(), llvm::BranchInst::isUnconditional(), llvm::SmallVectorTemplateBase< T, isPodLike >::push_back(), llvm::succ_begin(), and llvm::succ_end().

Referenced by llvm::FoldBranchToCommonDest().

static bool isSafeToHoistInvoke	(	BasicBlock *	BB1,
		BasicBlock *	BB2,
		Instruction *	I1,
		Instruction *	I2
	)		[static]

Definition at line 1041 of file SimplifyCFG.cpp.

References llvm::dyn_cast(), llvm::PHINode::getIncomingValueForBlock(), llvm::succ_begin(), and llvm::succ_end().

Referenced by HoistThenElseCodeToIf().

static Value* isSafeToSpeculateStore	(	Instruction *	I,
		BasicBlock *	BrBB,
		BasicBlock *	StoreBB,
		BasicBlock *	EndBB
	)		[static]

Determine if we can hoist sink a sole store instruction out of a conditional block.

We are looking for code like the following: BrBB: store i32 add, i32* arrayidx2 ... // No other stores or function calls (we could be calling a memory ... // function). cmp = icmp ult x, y br i1 cmp, label EndBB, label ThenBB ThenBB: store i32 add5, i32* arrayidx2 br label EndBB EndBB: ... We are going to transform this into: BrBB: store i32 add, i32* arrayidx2 ... // cmp = icmp ult x, y add.add5 = select i1 cmp, i32 add, add5 store i32 add.add5, i32* arrayidx2 ...

Returns:

The pointer to the value of the previous store if the store can be hoisted into the predecessor block. 0 otherwise.

Definition at line 1365 of file SimplifyCFG.cpp.

References llvm::dyn_cast(), llvm::StoreInst::getPointerOperand(), llvm::StoreInst::getValueOperand(), I, llvm::StoreInst::isSimple(), llvm::Instruction::mayHaveSideEffects(), llvm::BasicBlock::rbegin(), and llvm::BasicBlock::rend().

Referenced by SpeculativelyExecuteBB().

static Constant* LookupConstant	(	Value *	V,
		const SmallDenseMap< Value *, Constant * > &	ConstantPool
	)		[static]

LookupConstant - If V is a Constant, return it. Otherwise, try to look up its constant value in ConstantPool, returning 0 if it's not there.

Definition at line 3337 of file SimplifyCFG.cpp.

References llvm::CallingConv::C, and llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, InlineBuckets, KeyInfoT >, KeyT, ValueT, KeyInfoT >::lookup().

Referenced by ConstantFold(), and GetCaseResults().

static bool passingValueIsAlwaysUndefined	(	Value *	V,
		Instruction *	I
	)		[static]

Check if passing a value to an instruction will cause undefined behavior.

Definition at line 4023 of file SimplifyCFG.cpp.

References llvm::CallingConv::C, llvm::dyn_cast(), llvm::BasicBlock::end(), llvm::Instruction::getParent(), I, llvm::Constant::isNullValue(), LI, llvm::Value::use_begin(), and llvm::Value::use_empty().

Referenced by removeUndefIntroducingPredecessor().

static bool removeUndefIntroducingPredecessor

(

BasicBlock *

BB

)

[static]

If BB has an incoming value that will always trigger undefined behavior (eg. null pointer dereference), remove the branch leading here.

Definition at line 4065 of file SimplifyCFG.cpp.

References llvm::BasicBlock::begin(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateBr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateUnreachable(), llvm::dyn_cast(), llvm::Instruction::eraseFromParent(), llvm::PHINode::getIncomingBlock(), llvm::PHINode::getIncomingValue(), llvm::PHINode::getNumIncomingValues(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::BranchInst::isUnconditional(), passingValueIsAlwaysUndefined(), llvm::PHI, and llvm::BasicBlock::removePredecessor().

static bool SafeToMergeTerminators	(	TerminatorInst *	SI1,
		TerminatorInst *	SI2
	)		[static]

SafeToMergeTerminators - Return true if it is safe to merge these two terminator instructions together.

Definition at line 119 of file SimplifyCFG.cpp.

References llvm::SmallPtrSet< PtrType, SmallSize >::count(), llvm::PHINode::getIncomingValueForBlock(), llvm::Instruction::getParent(), I, llvm::succ_begin(), and llvm::succ_end().

Referenced by llvm::FoldBranchToCommonDest().

static bool ShouldBuildLookupTable	(	SwitchInst *	SI,
		uint64_t	TableSize,
		const TargetTransformInfo &	TTI,
		const DataLayout *	TD,
		const SmallDenseMap< PHINode *, Type * > &	ResultTypes
	)		[static]

ShouldBuildLookupTable - Determine whether a lookup table should be built for this switch, based on the number of caes, size of the table and the types of the results.

Definition at line 3648 of file SimplifyCFG.cpp.

References llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, InlineBuckets, KeyInfoT >, KeyT, ValueT, KeyInfoT >::begin(), llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, InlineBuckets, KeyInfoT >, KeyT, ValueT, KeyInfoT >::end(), llvm::SwitchInst::getNumCases(), I, llvm::TargetTransformInfo::isTypeLegal(), and UINT64_MAX.

Referenced by SwitchToLookupTable().

static bool SimplifyBranchOnICmpChain	(	BranchInst *	BI,
		const DataLayout *	TD,
		IRBuilder<> &	Builder
	)		[static]

SimplifyBranchOnICmpChain - The specified branch is a conditional branch. Check to see if it is branching on an or/and chain of icmp instructions, and fold it into a switch instruction if so.

Definition at line 2749 of file SimplifyCFG.cpp.

References llvm::SwitchInst::addCase(), llvm::PHINode::addIncoming(), AddPredecessorToBlock(), llvm::APIntOps::And(), llvm::array_pod_sort(), llvm::BasicBlock::begin(), ConstantIntSortPredicate(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateCondBr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreatePtrToInt(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateSwitch(), llvm::dbgs(), DEBUG, llvm::dyn_cast(), llvm::Instruction::eraseFromParent(), EraseTerminatorInstAndDCECond(), GatherConstantCompares(), llvm::BranchInst::getCondition(), llvm::Value::getContext(), llvm::PHINode::getIncomingValueForBlock(), llvm::DataLayout::getIntPtrType(), llvm::Instruction::getOpcode(), llvm::Instruction::getParent(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::Value::getType(), llvm::Type::isPointerTy(), llvm::APIntOps::Or(), llvm::IRBuilderBase::SetInsertPoint(), llvm::BasicBlock::size(), llvm::BasicBlock::splitBasicBlock(), and llvm::swap().

static bool SimplifyCondBranchToCondBranch	(	BranchInst *	PBI,
		BranchInst *	BI
	)		[static]

SimplifyCondBranchToCondBranch - If we have a conditional branch as a predecessor of another block, this function tries to simplify it. We know that PBI and BI are both conditional branches, and BI is in one of the successor blocks of PBI - PBI branches to BI.

Definition at line 2306 of file SimplifyCFG.cpp.

References llvm::PHINode::addIncoming(), AddPredecessorToBlock(), llvm::StringRef::begin(), llvm::SmallVectorTemplateCommon< T >::begin(), llvm::BasicBlock::begin(), BlockIsSimpleEnoughToThreadThrough(), llvm::BasicBlock::Create(), llvm::PHINode::Create(), llvm::BranchInst::Create(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateNot(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateOr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateSelect(), llvm::dbgs(), DEBUG, llvm::dyn_cast(), llvm::SmallVectorTemplateCommon< T >::end(), ExtractBranchMetadata(), FitWeights(), llvm::ConstantInt::get(), llvm::BranchInst::getCondition(), llvm::Value::getContext(), llvm::PHINode::getIncomingValueForBlock(), llvm::Type::getInt1Ty(), llvm::Value::getName(), llvm::Instruction::getParent(), llvm::BasicBlock::getParent(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::BranchInst::isConditional(), llvm::LLVMContext::MD_prof, llvm::A64CC::NV, P, llvm::pred_begin(), llvm::pred_end(), llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::BranchInst::setCondition(), llvm::Instruction::setMetadata(), and llvm::BranchInst::setSuccessor().

static bool SimplifyCondBranchToTwoReturns	(	BranchInst *	BI,
		IRBuilder<> &	Builder
	)		[static]

SimplifyCondBranchToTwoReturns - If we found a conditional branch that goes to two returning blocks, try to merge them together into one return, introducing a select if the return values disagree.

Definition at line 1864 of file SimplifyCFG.cpp.

References llvm::IRBuilder< preserveNames, T, Inserter >::CreateRet(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateRetVoid(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateSelect(), llvm::dbgs(), DEBUG, EraseTerminatorInstAndDCECond(), llvm::BranchInst::getCondition(), llvm::BasicBlock::getFirstNonPHIOrDbg(), llvm::Instruction::getParent(), llvm::ReturnInst::getReturnValue(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::BranchInst::isConditional(), llvm::Instruction::isTerminator(), llvm::BasicBlock::removePredecessor(), and llvm::IRBuilderBase::SetInsertPoint().

static bool SimplifyIndirectBrOnSelect	(	IndirectBrInst *	IBI,
		SelectInst *	SI
	)		[static]

Definition at line 2609 of file SimplifyCFG.cpp.

References llvm::dyn_cast(), llvm::BlockAddress::getBasicBlock(), llvm::SelectInst::getCondition(), llvm::SelectInst::getFalseValue(), llvm::SelectInst::getTrueValue(), and SimplifyTerminatorOnSelect().

static bool SimplifySwitchOnSelect	(	SwitchInst *	SI,
		SelectInst *	Select
	)		[static]

Definition at line 2573 of file SimplifyCFG.cpp.

References llvm::dyn_cast(), llvm::SwitchInst::findCaseValue(), GetBranchWeights(), llvm::SelectInst::getCondition(), llvm::SelectInst::getFalseValue(), llvm::SwitchInst::getNumCases(), llvm::SelectInst::getTrueValue(), HasBranchWeights(), SimplifyTerminatorOnSelect(), and llvm::SmallVectorTemplateCommon< T >::size().

static bool SimplifyTerminatorOnSelect	(	TerminatorInst *	OldTerm,
		Value *	Cond,
		BasicBlock *	TrueBB,
		BasicBlock *	FalseBB,
		uint32_t	TrueWeight,
		uint32_t	FalseWeight
	)		[static]

Definition at line 2508 of file SimplifyCFG.cpp.

References llvm::IRBuilder< preserveNames, T, Inserter >::CreateBr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateCondBr(), EraseTerminatorInstAndDCECond(), llvm::Value::getContext(), llvm::Instruction::getDebugLoc(), llvm::TerminatorInst::getNumSuccessors(), llvm::Instruction::getParent(), llvm::TerminatorInst::getSuccessor(), I, llvm::LLVMContext::MD_prof, llvm::BasicBlock::removePredecessor(), llvm::IRBuilderBase::SetCurrentDebugLocation(), and llvm::Instruction::setMetadata().

Referenced by SimplifyIndirectBrOnSelect(), and SimplifySwitchOnSelect().

static bool SinkThenElseCodeToEnd

(

BranchInst *

BI1

)

[static]

SinkThenElseCodeToEnd - Given an unconditional branch that goes to BBEnd, check whether BBEnd has only two predecessors and the other predecessor ends with an unconditional branch. If it is true, sink any common code in the two predecessors to BBEnd.

Definition at line 1174 of file SimplifyCFG.cpp.

References llvm::PHINode::addIncoming(), llvm::BasicBlock::begin(), llvm::PHINode::Create(), llvm::dbgs(), DEBUG, llvm::dyn_cast(), llvm::BasicBlock::end(), llvm::Instruction::eraseFromParent(), llvm::BasicBlock::getInstList(), llvm::Value::getName(), llvm::User::getNumOperands(), llvm::User::getOperand(), llvm::Instruction::getParent(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::Value::getType(), llvm::Value::hasOneUse(), I, llvm::Value::intersectOptionalDataWith(), llvm::Instruction::isSameOperationAs(), llvm::BranchInst::isUnconditional(), llvm::Instruction::mayHaveSideEffects(), llvm::Instruction::mayReadOrWriteMemory(), llvm::pred_begin(), llvm::pred_end(), llvm::Value::replaceAllUsesWith(), llvm::User::setOperand(), and llvm::Value::use_empty().

static bool SpeculativelyExecuteBB	(	BranchInst *	BI,
		BasicBlock *	ThenBB
	)		[static]

Speculate a conditional basic block flattening the CFG.

Note that this is a very risky transform currently. Speculating instructions like this is most often not desirable. Instead, there is an MI pass which can do it with full awareness of the resource constraints. However, some cases are "obvious" and we should do directly. An example of this is speculating a single, reasonably cheap instruction.

There is only one distinct advantage to flattening the CFG at the IR level: it makes very common but simplistic optimizations such as are common in instcombine and the DAG combiner more powerful by removing CFG edges and modeling their effects with easier to reason about SSA value graphs.

An illustration of this transform is turning this IR:

   BB:
     %cmp = icmp ult %x, %y
     br i1 %cmp, label %EndBB, label %ThenBB
   ThenBB:
     %sub = sub %x, %y
     br label BB2
   EndBB:
     %phi = phi [ %sub, %ThenBB ], [ 0, %EndBB ]
     ...

Into this IR:

   BB:
     %cmp = icmp ult %x, %y
     %sub = sub %x, %y
     %cond = select i1 %cmp, 0, %sub
     ...

Returns:

true if the conditional block is removed.

Definition at line 1436 of file SimplifyCFG.cpp.

References llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT >::begin(), llvm::BasicBlock::begin(), ComputeSpeculationCost(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateSelect(), llvm::dbgs(), DEBUG, llvm::dyn_cast(), llvm::BasicBlock::end(), llvm::PHINode::getBasicBlockIndex(), llvm::BranchInst::getCondition(), llvm::PHINode::getIncomingValue(), llvm::PHINode::getIncomingValueForBlock(), llvm::BasicBlock::getInstList(), llvm::Value::getName(), llvm::Instruction::getParent(), llvm::TerminatorInst::getSuccessor(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::StoreInst::getValueOperand(), HoistCondStores, I, isSafeToSpeculateStore(), llvm::isSafeToSpeculativelyExecute(), llvm::Instruction::mayHaveSideEffects(), llvm::User::op_begin(), llvm::User::op_end(), PHINodeFoldingThreshold, llvm::prior(), llvm::PHINode::setIncomingValue(), llvm::User::setOperand(), and llvm::swap().

STATISTIC	(	NumBitMaps	,
		"Number of switch instructions turned into bitmaps"
	)

STATISTIC	(	NumLookupTables	,
		"Number of switch instructions turned into lookup tables"
	)

STATISTIC	(	NumSinkCommons	,
		"Number of common instructions sunk down to the end block"
	)

STATISTIC	(	NumSpeculations	,
		"Number of speculative executed instructions"
	)

static bool SwitchToLookupTable	(	SwitchInst *	SI,
		IRBuilder<> &	Builder,
		const TargetTransformInfo &	TTI,
		const DataLayout *	TD
	)		[static]

SwitchToLookupTable - If the switch is only used to initialize one or more phi nodes in a common successor block with different constant values, replace the switch with lookup tables.

Definition at line 3693 of file SimplifyCFG.cpp.

References llvm::SwitchInst::case_begin(), llvm::SwitchInst::case_end(), llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, InlineBuckets, KeyInfoT >, KeyT, ValueT, KeyInfoT >::count(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateBr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateCondBr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateICmpULT(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateRet(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateSub(), llvm::Instruction::eraseFromParent(), GetCaseResults(), llvm::SwitchInst::getCondition(), llvm::Module::getContext(), llvm::SwitchInst::getDefaultDest(), llvm::BasicBlock::getFirstNonPHIOrDbg(), llvm::APInt::getLimitedValue(), llvm::SwitchInst::getNumCases(), llvm::SwitchInst::getNumSuccessors(), llvm::Instruction::getParent(), llvm::BasicBlock::getParent(), llvm::GlobalValue::getParent(), llvm::SwitchInst::getSuccessor(), llvm::Value::getType(), llvm::ConstantInt::getType(), llvm::ConstantInt::getValue(), I, llvm::PHI, llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::BasicBlock::removePredecessor(), llvm::IRBuilderBase::SetInsertPoint(), llvm::APInt::sgt(), ShouldBuildLookupTable(), llvm::TargetTransformInfo::shouldBuildLookupTables(), llvm::SmallVectorTemplateCommon< T >::size(), and llvm::APInt::slt().

static bool TryToSimplifyUncondBranchWithICmpInIt	(	ICmpInst *	ICI,
		IRBuilder<> &	Builder,
		const TargetTransformInfo &	TTI,
		const DataLayout *	TD
	)		[static]

TryToSimplifyUncondBranchWithICmpInIt - This is called when we find an icmp instruction (a seteq/setne with a constant) as the only instruction in a block that ends with an uncond branch. We are looking for a very specific pattern that occurs when "A == 1 || A == 2 || A == 3" gets simplified. In this case, we merge the first two "or's of icmp" into a switch, but then the default value goes to an uncond block with a seteq in it, we get something like:

switch i8 A, label DEFAULT [ i8 1, label end i8 2, label end ] DEFAULT: tmp = icmp eq i8 A, 92 br label end end: ... = phi i1 [ true, entry ], [ tmp, DEFAULT ], [ true, entry ]

We prefer to split the edge to 'end' so that there is a true/false entry to the PHI, merging the third icmp into the switch.

Definition at line 2642 of file SimplifyCFG.cpp.

References llvm::SwitchInst::addCase(), llvm::PHINode::addIncoming(), llvm::BasicBlock::begin(), llvm::SwitchInst::case_default(), llvm::BasicBlock::Create(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateBr(), llvm::dyn_cast(), llvm::Instruction::eraseFromParent(), llvm::SwitchInst::findCaseDest(), llvm::SwitchInst::findCaseValue(), llvm::BasicBlock::front(), GetBranchWeights(), llvm::SwitchInst::getCondition(), llvm::BasicBlock::getContext(), llvm::Value::getContext(), llvm::Instruction::getDebugLoc(), llvm::SwitchInst::getDefaultDest(), llvm::ConstantInt::getFalse(), llvm::SwitchInst::getNumCases(), llvm::User::getOperand(), llvm::Instruction::getParent(), llvm::BasicBlock::getParent(), llvm::CmpInst::getPredicate(), llvm::BasicBlock::getSinglePredecessor(), llvm::TerminatorInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::ConstantInt::getTrue(), HasBranchWeights(), llvm::Value::hasOneUse(), llvm::CmpInst::ICMP_EQ, llvm::LLVMContext::MD_prof, llvm::Value::replaceAllUsesWith(), llvm::IRBuilderBase::SetCurrentDebugLocation(), llvm::IRBuilderBase::SetInsertPoint(), llvm::Instruction::setMetadata(), llvm::User::setOperand(), llvm::SimplifyCFG(), llvm::SimplifyInstruction(), std::swap(), and llvm::Instruction::use_back().

static bool TurnSwitchRangeIntoICmp	(	SwitchInst *	SI,
		IRBuilder<> &	Builder
	)		[static]

TurnSwitchRangeIntoICmp - Turns a switch with that contains only a integer range comparison into a sub, an icmp and a branch.

Definition at line 3134 of file SimplifyCFG.cpp.

References llvm::array_pod_sort(), llvm::SwitchInst::case_begin(), llvm::SwitchInst::case_end(), ConstantIntSortPredicate(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateAdd(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateCondBr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateICmpULT(), llvm::Instruction::eraseFromParent(), llvm::ConstantInt::get(), GetBranchWeights(), llvm::SwitchInst::CaseIteratorT< SwitchInstTy, ConstantIntTy, SubsetsItTy, BasicBlockTy >::getCaseSuccessor(), llvm::SwitchInst::CaseIteratorT< SwitchInstTy, ConstantIntTy, SubsetsItTy, BasicBlockTy >::getCaseValue(), llvm::SwitchInst::getCondition(), llvm::Value::getContext(), llvm::SwitchInst::getDefaultDest(), llvm::Value::getName(), llvm::ConstantExpr::getNeg(), llvm::SwitchInst::getNumCases(), llvm::Instruction::getParent(), llvm::ConstantInt::getTrue(), llvm::Value::getType(), HasBranchWeights(), I, llvm::Constant::isNullValue(), llvm::LLVMContext::MD_prof, llvm::Instruction::setMetadata(), and llvm::SmallVectorTemplateCommon< T >::size().

static bool ValidLookupTableConstant

(

Constant *

C

)

[static]

ValidLookupTableConstant - Return true if the backend will be able to handle initializing an array of constants like C.

Definition at line 3324 of file SimplifyCFG.cpp.

References llvm::CallingConv::C.

Referenced by GetCaseResults().

static bool ValuesOverlap	(	std::vector< ValueEqualityComparisonCase > &	C1,
		std::vector< ValueEqualityComparisonCase > &	C2
	)		[static]

ValuesOverlap - Return true if there are any keys in C1 that exist in C2 as well.

Definition at line 582 of file SimplifyCFG.cpp.

References llvm::array_pod_sort(), std::swap(), llvm::NVPTX::PTXLdStInstCode::V2, and llvm::Value::Value().

---

Variable Documentation

cl::opt<bool> DupRet("simplifycfg-dup-ret", cl::Hidden, cl::init(false), cl::desc("Duplicate return instructions into unconditional branches")) [static]

cl::opt<bool> HoistCondStores("simplifycfg-hoist-cond-stores", cl::Hidden, cl::init(true), cl::desc("Hoist conditional stores if an unconditional store preceeds")) [static]

Referenced by SpeculativelyExecuteBB().

cl::opt<unsigned> PHINodeFoldingThreshold("phi-node-folding-threshold", cl::Hidden, cl::init(1), cl::desc("Control the amount of phi node folding to perform (default = 1)")) [static]

Referenced by FoldTwoEntryPHINode(), and SpeculativelyExecuteBB().

cl::opt<bool> SinkCommon("simplifycfg-sink-common", cl::Hidden, cl::init(true), cl::desc("Sink common instructions down to the end block")) [static]