LLVM 20.0.0git
Classes | Public Member Functions | Public Attributes | List of all members
llvm::SwitchCG::SwitchLowering Class Referenceabstract

#include "llvm/CodeGen/SwitchLoweringUtils.h"

Inheritance diagram for llvm::SwitchCG::SwitchLowering:
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Classes

struct  SplitWorkItemInfo
 

Public Member Functions

 SwitchLowering (FunctionLoweringInfo &funcinfo)
 
void init (const TargetLowering &tli, const TargetMachine &tm, const DataLayout &dl)
 
void findJumpTables (CaseClusterVector &Clusters, const SwitchInst *SI, std::optional< SDLoc > SL, MachineBasicBlock *DefaultMBB, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI)
 
bool buildJumpTable (const CaseClusterVector &Clusters, unsigned First, unsigned Last, const SwitchInst *SI, const std::optional< SDLoc > &SL, MachineBasicBlock *DefaultMBB, CaseCluster &JTCluster)
 
void findBitTestClusters (CaseClusterVector &Clusters, const SwitchInst *SI)
 
bool buildBitTests (CaseClusterVector &Clusters, unsigned First, unsigned Last, const SwitchInst *SI, CaseCluster &BTCluster)
 Build a bit test cluster from Clusters[First..Last].
 
virtual void addSuccessorWithProb (MachineBasicBlock *Src, MachineBasicBlock *Dst, BranchProbability Prob=BranchProbability::getUnknown())=0
 
unsigned caseClusterRank (const CaseCluster &CC, CaseClusterIt First, CaseClusterIt Last)
 Determine the rank by weight of CC in [First,Last].
 
SplitWorkItemInfo computeSplitWorkItemInfo (const SwitchWorkListItem &W)
 Compute information to balance the tree based on branch probabilities to create a near-optimal (in terms of search time given key frequency) binary search tree.
 
virtual ~SwitchLowering ()=default
 

Public Attributes

std::vector< CaseBlock > SwitchCases
 Vector of CaseBlock structures used to communicate SwitchInst code generation information.
 
std::vector< JumpTableBlock > JTCases
 Vector of JumpTable structures used to communicate SwitchInst code generation information.
 
std::vector< BitTestBlock > BitTestCases
 Vector of BitTestBlock structures used to communicate SwitchInst code generation information.
 

Detailed Description

Definition at line 258 of file SwitchLoweringUtils.h.

Constructor & Destructor Documentation

◆ SwitchLowering()

llvm::SwitchCG::SwitchLowering::SwitchLowering ( FunctionLoweringInfo &  funcinfo)
inline

Definition at line 260 of file SwitchLoweringUtils.h.

◆ ~SwitchLowering()

virtual llvm::SwitchCG::SwitchLowering::~SwitchLowering ( )
virtualdefault

References DL.

Member Function Documentation

◆ addSuccessorWithProb()

virtual void llvm::SwitchCG::SwitchLowering::addSuccessorWithProb ( MachineBasicBlock *  Src,
MachineBasicBlock *  Dst,
BranchProbability  Prob = BranchProbability::getUnknown() 
)
pure virtual

Implemented in llvm::SelectionDAGBuilder::SDAGSwitchLowering.

◆ buildBitTests()

bool SwitchCG::SwitchLowering::buildBitTests ( CaseClusterVector &  Clusters,
unsigned  First,
unsigned  Last,
const SwitchInst *  SI,
CaseCluster &  BTCluster 
)

Build a bit test cluster from Clusters[First..Last].

Returns false if it decides it's not a good idea.

Definition at line 367 of file SwitchLoweringUtils.cpp.

References assert(), llvm::SwitchCG::CaseBits::Bits, llvm::SwitchCG::CaseCluster::bitTests(), llvm::BitWidth, llvm::SwitchCG::CC_Range, llvm::BitVector::count(), DL, llvm::SwitchCG::CaseBits::ExtraProb, llvm::First, llvm::MachineBasicBlock::getNumber(), llvm::BranchProbability::getZero(), llvm::APInt::getZero(), llvm::Hi, High, I, if(), llvm::Last, llvm::Lo, llvm::Low, llvm::SwitchCG::CaseBits::Mask, MBB, llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::BitVector::set(), and llvm::sort().

◆ buildJumpTable()

bool SwitchCG::SwitchLowering::buildJumpTable ( const CaseClusterVector &  Clusters,
unsigned  First,
unsigned  Last,
const SwitchInst *  SI,
const std::optional< SDLoc > &  SL,
MachineBasicBlock *  DefaultMBB,
CaseCluster &  JTCluster 
)

Definition at line 192 of file SwitchLoweringUtils.cpp.

References assert(), llvm::SwitchCG::CC_Range, llvm::MachineJumpTableInfo::createJumpTableIndex(), llvm::MachineFunction::CreateMachineBasicBlock(), DL, llvm::Done, llvm::First, llvm::MachineFunction::getOrCreateJumpTableInfo(), llvm::BranchProbability::getZero(), High, I, llvm::SwitchCG::CaseCluster::jumpTable(), llvm::Last, llvm::Low, MBB, llvm::MachineBasicBlock::normalizeSuccProbs(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::size(), and llvm::APInt::slt().

Referenced by findJumpTables().

◆ caseClusterRank()

unsigned SwitchCG::SwitchLowering::caseClusterRank ( const CaseCluster &  CC,
CaseClusterIt  First,
CaseClusterIt  Last 
)

Determine the rank by weight of CC in [First,Last].

If CC has more weight than each cluster in the range, its rank is 0.

Definition at line 499 of file SwitchLoweringUtils.cpp.

References CC, llvm::First, llvm::Last, and X.

◆ computeSplitWorkItemInfo()

llvm::SwitchCG::SwitchLowering::SplitWorkItemInfo SwitchCG::SwitchLowering::computeSplitWorkItemInfo ( const SwitchWorkListItem &  W)

Compute information to balance the tree based on branch probabilities to create a near-optimal (in terms of search time given key frequency) binary search tree.

See e.g. Kurt Mehlhorn "Nearly Optimal Binary Search Trees" (1975).

Definition at line 512 of file SwitchLoweringUtils.cpp.

References assert(), CC, and I.

◆ findBitTestClusters()

void SwitchCG::SwitchLowering::findBitTestClusters ( CaseClusterVector &  Clusters,
const SwitchInst *  SI 
)

Definition at line 268 of file SwitchLoweringUtils.cpp.

References assert(), llvm::BitWidth, llvm::CallingConv::C, llvm::SwitchCG::CC_JumpTable, llvm::SwitchCG::CC_Range, llvm::BitVector::count(), DL, llvm::First, llvm::MachineBasicBlock::getNumber(), llvm::EVT::getSizeInBits(), High, llvm::Last, MBB, N, llvm::None, llvm::BitVector::set(), and llvm::ISD::SHL.

◆ findJumpTables()

void SwitchCG::SwitchLowering::findJumpTables ( CaseClusterVector &  Clusters,
const SwitchInst *  SI,
std::optional< SDLoc >  SL,
MachineBasicBlock *  DefaultMBB,
ProfileSummaryInfo *  PSI,
BlockFrequencyInfo *  BFI 
)

Definition at line 46 of file SwitchLoweringUtils.cpp.

References llvm::TargetLoweringBase::areJTsAllowed(), assert(), buildJumpTable(), llvm::CallingConv::C, llvm::SwitchCG::CC_Range, llvm::First, llvm::SwitchCG::getJumpTableNumCases(), llvm::SwitchCG::getJumpTableRange(), llvm::TargetLoweringBase::getMinimumJumpTableEntries(), llvm::TargetMachine::getOptLevel(), llvm::Hi, High, I, llvm::TargetLoweringBase::isSuitableForJumpTable(), llvm::Last, llvm::Lo, N, llvm::None, Range, and UINT64_MAX.

◆ init()

void llvm::SwitchCG::SwitchLowering::init ( const TargetLowering &  tli,
const TargetMachine &  tm,
const DataLayout &  dl 
)
inline

Definition at line 262 of file SwitchLoweringUtils.h.

References DL.

Member Data Documentation

◆ BitTestCases

std::vector<BitTestBlock> llvm::SwitchCG::SwitchLowering::BitTestCases

Vector of BitTestBlock structures used to communicate SwitchInst code generation information.

Definition at line 279 of file SwitchLoweringUtils.h.

◆ JTCases

std::vector<JumpTableBlock> llvm::SwitchCG::SwitchLowering::JTCases

Vector of JumpTable structures used to communicate SwitchInst code generation information.

Definition at line 275 of file SwitchLoweringUtils.h.

◆ SwitchCases

std::vector<CaseBlock> llvm::SwitchCG::SwitchLowering::SwitchCases

Vector of CaseBlock structures used to communicate SwitchInst code generation information.

Definition at line 271 of file SwitchLoweringUtils.h.

The documentation for this class was generated from the following files:
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