ControlHeightReduction.cpp File Reference

#include "llvm/Transforms/Instrumentation/ControlHeightReduction.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/RegionInfo.h"
#include "llvm/Analysis/RegionIterator.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/PassManager.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/BranchProbability.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Transforms/Utils.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
#include <set>
#include <sstream>

Include dependency graph for ControlHeightReduction.cpp:

Go to the source code of this file.

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

Macros
#define	DEBUG_TYPE   "chr"
#define	CHR_DEBUG(X)   LLVM_DEBUG(X)

Functions
static void	parseCHRFilterFiles ()
	INITIALIZE_PASS_BEGIN (ControlHeightReductionLegacyPass, "chr", "Reduce control height in the hot paths", false, false) INITIALIZE_PASS_END(ControlHeightReductionLegacyPass
static raw_ostream LLVM_ATTRIBUTE_UNUSED &	operator<< (raw_ostream &OS, const CHRStats &Stats)
static raw_ostream &	operator<< (raw_ostream &OS, const CHRScope &Scope)
static bool	shouldApply (Function &F, ProfileSummaryInfo &PSI)
static void LLVM_ATTRIBUTE_UNUSED	dumpIR (Function &F, const char *Label, CHRStats *Stats)
static bool	isHoistableInstructionType (Instruction *I)
static bool	isHoistable (Instruction *I, DominatorTree &DT)
static const std::set< Value * > &	getBaseValues (Value *V, DominatorTree &DT, DenseMap< Value *, std::set< Value * >> &Visited)
static bool	checkHoistValue (Value *V, Instruction *InsertPoint, DominatorTree &DT, DenseSet< Instruction * > &Unhoistables, DenseSet< Instruction * > *HoistStops, DenseMap< Instruction *, bool > &Visited)
static bool	checkMDProf (MDNode *MD, BranchProbability &TrueProb, BranchProbability &FalseProb)
static BranchProbability	getCHRBiasThreshold ()
template<typename K , typename S , typename M >
static bool	checkBias (K *Key, BranchProbability TrueProb, BranchProbability FalseProb, S &TrueSet, S &FalseSet, M &BiasMap)
static bool	checkBiasedBranch (BranchInst *BI, Region *R, DenseSet< Region * > &TrueBiasedRegionsGlobal, DenseSet< Region * > &FalseBiasedRegionsGlobal, DenseMap< Region *, BranchProbability > &BranchBiasMap)
static bool	checkBiasedSelect (SelectInst *SI, Region *R, DenseSet< SelectInst * > &TrueBiasedSelectsGlobal, DenseSet< SelectInst * > &FalseBiasedSelectsGlobal, DenseMap< SelectInst *, BranchProbability > &SelectBiasMap)
static Instruction *	getBranchInsertPoint (RegInfo &RI)
static DenseSet< Value * >	getCHRConditionValuesForRegion (RegInfo &RI)
static bool	shouldSplit (Instruction *InsertPoint, DenseSet< Value * > &PrevConditionValues, DenseSet< Value * > &ConditionValues, DominatorTree &DT, DenseSet< Instruction * > &Unhoistables)
static void	getSelectsInScope (CHRScope *Scope, DenseSet< Instruction * > &Output)
static bool	hasAtLeastTwoBiasedBranches (CHRScope *Scope)
static bool	CHRScopeSorter (CHRScope *Scope1, CHRScope *Scope2)
static void	hoistValue (Value *V, Instruction *HoistPoint, Region *R, HoistStopMapTy &HoistStopMap, DenseSet< Instruction * > &HoistedSet, DenseSet< PHINode * > &TrivialPHIs, DominatorTree &DT)
static void	hoistScopeConditions (CHRScope *Scope, Instruction *HoistPoint, DenseSet< PHINode * > &TrivialPHIs, DominatorTree &DT)
static bool	negateICmpIfUsedByBranchOrSelectOnly (ICmpInst *ICmp, Instruction *ExcludedUser, CHRScope *Scope)
static void	insertTrivialPHIs (CHRScope *Scope, BasicBlock *EntryBlock, BasicBlock *ExitBlock, DenseSet< PHINode * > &TrivialPHIs)
static void LLVM_ATTRIBUTE_UNUSED	assertCHRRegionsHaveBiasedBranchOrSelect (CHRScope *Scope)
static void LLVM_ATTRIBUTE_UNUSED	assertBranchOrSelectConditionHoisted (CHRScope *Scope, BasicBlock *PreEntryBlock)
static void LLVM_ATTRIBUTE_UNUSED	dumpScopes (SmallVectorImpl< CHRScope * > &Scopes, const char *Label)

Variables
static cl::opt< bool >	ForceCHR ("force-chr", cl::init(false), cl::Hidden, cl::desc("Apply CHR for all functions"))
static cl::opt< double >	CHRBiasThreshold ("chr-bias-threshold", cl::init(0.99), cl::Hidden, cl::desc("CHR considers a branch bias greater than this ratio as biased"))
static cl::opt< unsigned >	CHRMergeThreshold ("chr-merge-threshold", cl::init(2), cl::Hidden, cl::desc("CHR merges a group of N branches/selects where N >= this value"))
static cl::opt< std::string >	CHRModuleList ("chr-module-list", cl::init(""), cl::Hidden, cl::desc("Specify file to retrieve the list of modules to apply CHR to"))
static cl::opt< std::string >	CHRFunctionList ("chr-function-list", cl::init(""), cl::Hidden, cl::desc("Specify file to retrieve the list of functions to apply CHR to"))
static StringSet	CHRModules
static StringSet	CHRFunctions
	chr
Reduce control height in the hot	paths
Reduce control height in the hot	false

Macro Definition Documentation

CHR_DEBUG

#define CHR_DEBUG

(

X

)

LLVM_DEBUG(X)

Definition at line 48 of file ControlHeightReduction.cpp.

DEBUG_TYPE

#define DEBUG_TYPE   "chr"

Definition at line 46 of file ControlHeightReduction.cpp.

Function Documentation

assertBranchOrSelectConditionHoisted()

static void LLVM_ATTRIBUTE_UNUSED assertBranchOrSelectConditionHoisted ( CHRScope *  Scope, BasicBlock *  PreEntryBlock  )

static

Definition at line 1672 of file ControlHeightReduction.cpp.

References assert(), CHR_DEBUG, llvm::dbgs(), I, llvm::RISCVFenceField::R, and SI.

assertCHRRegionsHaveBiasedBranchOrSelect()

static void LLVM_ATTRIBUTE_UNUSED assertCHRRegionsHaveBiasedBranchOrSelect ( CHRScope *  Scope )

static

Definition at line 1651 of file ControlHeightReduction.cpp.

References assert(), and SI.

checkBias()

template<typename K , typename S , typename M >

static bool checkBias ( K *  Key, BranchProbability  TrueProb, BranchProbability  FalseProb, S &  TrueSet, S &  FalseSet, M &  BiasMap  )

static

Definition at line 642 of file ControlHeightReduction.cpp.

References getCHRBiasThreshold().

Referenced by checkBiasedBranch(), and checkBiasedSelect().

checkBiasedBranch()

static bool checkBiasedBranch ( BranchInst *  BI, Region *  R, DenseSet< Region * > &  TrueBiasedRegionsGlobal, DenseSet< Region * > &  FalseBiasedRegionsGlobal, DenseMap< Region *, BranchProbability > &  BranchBiasMap  )

static

Definition at line 660 of file ControlHeightReduction.cpp.

References assert(), checkBias(), checkMDProf(), CHR_DEBUG, llvm::dbgs(), llvm::Instruction::getMetadata(), llvm::BranchInst::getSuccessor(), llvm::BranchInst::isConditional(), llvm::RISCVFenceField::R, and std::swap().

checkBiasedSelect()

static bool checkBiasedSelect ( SelectInst *  SI, Region *  R, DenseSet< SelectInst * > &  TrueBiasedSelectsGlobal, DenseSet< SelectInst * > &  FalseBiasedSelectsGlobal, DenseMap< SelectInst *, BranchProbability > &  SelectBiasMap  )

static

Definition at line 691 of file ControlHeightReduction.cpp.

References checkBias(), checkMDProf(), CHR_DEBUG, llvm::dbgs(), and SI.

checkHoistValue()

static bool checkHoistValue ( Value *  V, Instruction *  InsertPoint, DominatorTree &  DT, DenseSet< Instruction * > &  Unhoistables, DenseSet< Instruction * > *  HoistStops, DenseMap< Instruction *, bool > &  Visited  )

static

Definition at line 551 of file ControlHeightReduction.cpp.

References assert(), llvm::detail::DenseSetImpl< ValueT, DenseMap< ValueT, detail::DenseSetEmpty, DenseMapInfo< ValueT >, detail::DenseSetPair< ValueT > >, DenseMapInfo< ValueT > >::begin(), CHR_DEBUG, llvm::detail::DenseSetImpl< ValueT, DenseMap< ValueT, detail::DenseSetEmpty, DenseMapInfo< ValueT >, detail::DenseSetPair< ValueT > >, DenseMapInfo< ValueT > >::count(), llvm::dbgs(), llvm::DominatorTree::dominates(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::end(), llvm::detail::DenseSetImpl< ValueT, DenseMap< ValueT, detail::DenseSetEmpty, DenseMapInfo< ValueT >, detail::DenseSetPair< ValueT > >, DenseMapInfo< ValueT > >::end(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::find(), llvm::DominatorTreeBase< NodeT, IsPostDom >::getNode(), llvm::Instruction::getParent(), I, llvm::detail::DenseSetImpl< ValueT, DenseMap< ValueT, detail::DenseSetEmpty, DenseMapInfo< ValueT >, detail::DenseSetPair< ValueT > >, DenseMapInfo< ValueT > >::insert(), and isHoistable().

Referenced by shouldSplit().

checkMDProf()

static bool checkMDProf ( MDNode *  MD, BranchProbability &  TrueProb, BranchProbability &  FalseProb  )

static

Definition at line 605 of file ControlHeightReduction.cpp.

References assert(), llvm::MDNode::getNumOperands(), llvm::MDNode::getOperand(), llvm::MDString::getString(), llvm::ConstantInt::getValue(), and llvm::APInt::getZExtValue().

Referenced by checkBiasedBranch(), and checkBiasedSelect().

CHRScopeSorter()

static bool CHRScopeSorter ( CHRScope *  Scope1, CHRScope *  Scope2  )

static

Definition at line 1452 of file ControlHeightReduction.cpp.

dumpIR()

static void LLVM_ATTRIBUTE_UNUSED dumpIR ( Function &  F, const char *  Label, CHRStats *  Stats  )

static

Definition at line 454 of file ControlHeightReduction.cpp.

References CHR_DEBUG, llvm::dbgs(), F, and Stats.

dumpScopes()

static void LLVM_ATTRIBUTE_UNUSED dumpScopes ( SmallVectorImpl< CHRScope * > &  Scopes, const char *  Label  )

static

Definition at line 2002 of file ControlHeightReduction.cpp.

References llvm::dbgs().

getBaseValues()

static const std::set<Value *>& getBaseValues ( Value *  V, DominatorTree &  DT, DenseMap< Value *, std::set< Value * >> &  Visited  )

static

Definition at line 515 of file ControlHeightReduction.cpp.

References I, isHoistable(), and move.

Referenced by shouldSplit().

getBranchInsertPoint()

static Instruction* getBranchInsertPoint ( RegInfo &  RI )

static

Definition at line 711 of file ControlHeightReduction.cpp.

References assert(), llvm::detail::DenseSetImpl< ValueT, DenseMap< ValueT, detail::DenseSetEmpty, DenseMapInfo< ValueT >, detail::DenseSetPair< ValueT > >, DenseMapInfo< ValueT > >::contains(), llvm::BasicBlock::getTerminator(), I, llvm::detail::DenseSetImpl< ValueT, DenseMap< ValueT, detail::DenseSetEmpty, DenseMapInfo< ValueT >, detail::DenseSetPair< ValueT > >, DenseMapInfo< ValueT > >::insert(), llvm::RISCVFenceField::R, and SI.

getCHRBiasThreshold()

static BranchProbability getCHRBiasThreshold ( )

static

Definition at line 632 of file ControlHeightReduction.cpp.

References CHRBiasThreshold.

Referenced by checkBias().

getCHRConditionValuesForRegion()

static DenseSet<Value *> getCHRConditionValuesForRegion ( RegInfo &  RI )

static

Definition at line 1057 of file ControlHeightReduction.cpp.

References llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::insert(), and SI.

getSelectsInScope()

static void getSelectsInScope ( CHRScope *  Scope, DenseSet< Instruction * > &  Output  )

static

Definition at line 1138 of file ControlHeightReduction.cpp.

References SI.

hasAtLeastTwoBiasedBranches()

static bool hasAtLeastTwoBiasedBranches ( CHRScope *  Scope )

static

Definition at line 1347 of file ControlHeightReduction.cpp.

References CHRMergeThreshold.

hoistScopeConditions()

static void hoistScopeConditions ( CHRScope *  Scope, Instruction *  HoistPoint, DenseSet< PHINode * > &  TrivialPHIs, DominatorTree &  DT  )

static

Definition at line 1513 of file ControlHeightReduction.cpp.

References hoistValue(), llvm::RISCVFenceField::R, and SI.

hoistValue()

static void hoistValue ( Value *  V, Instruction *  HoistPoint, Region *  R, HoistStopMapTy &  HoistStopMap, DenseSet< Instruction * > &  HoistedSet, DenseSet< PHINode * > &  TrivialPHIs, DominatorTree &  DT  )

static

Definition at line 1465 of file ControlHeightReduction.cpp.

References assert(), CHR_DEBUG, llvm::detail::DenseSetImpl< ValueT, DenseMap< ValueT, detail::DenseSetEmpty, DenseMapInfo< ValueT >, detail::DenseSetPair< ValueT > >, DenseMapInfo< ValueT > >::count(), llvm::dbgs(), llvm::DominatorTree::dominates(), llvm::DominatorTreeBase< NodeT, IsPostDom >::getNode(), llvm::Instruction::getParent(), I, llvm::detail::DenseSetImpl< ValueT, DenseMap< ValueT, detail::DenseSetEmpty, DenseMapInfo< ValueT >, detail::DenseSetPair< ValueT > >, DenseMapInfo< ValueT > >::insert(), isHoistableInstructionType(), IT, and llvm::RISCVFenceField::R.

Referenced by hoistScopeConditions().

INITIALIZE_PASS_BEGIN()

INITIALIZE_PASS_BEGIN	(	ControlHeightReductionLegacyPass	,
		"chr"	,
		"Reduce control height in the hot paths"	,
		false	,
		false
	)

insertTrivialPHIs()

static void insertTrivialPHIs ( CHRScope *  Scope, BasicBlock *  EntryBlock, BasicBlock *  ExitBlock, DenseSet< PHINode * > &  TrivialPHIs  )

static

Definition at line 1588 of file ControlHeightReduction.cpp.

References llvm::PHINode::addIncoming(), BB, CHR_DEBUG, llvm::dbgs(), llvm::BasicBlock::front(), I, llvm::SetVector< T, SmallVector< T, N >, SmallDenseSet< T, N > >::insert(), llvm::detail::DenseSetImpl< ValueT, DenseMap< ValueT, detail::DenseSetEmpty, DenseMapInfo< ValueT >, detail::DenseSetPair< ValueT > >, DenseMapInfo< ValueT > >::insert(), llvm::pred_size(), llvm::predecessors(), and Users.

isHoistable()

static bool isHoistable ( Instruction *  I, DominatorTree &  DT  )

static

Definition at line 503 of file ControlHeightReduction.cpp.

References I, isHoistableInstructionType(), and llvm::isSafeToSpeculativelyExecute().

Referenced by checkHoistValue(), and getBaseValues().

isHoistableInstructionType()

static bool isHoistableInstructionType ( Instruction *  I )

static

Definition at line 494 of file ControlHeightReduction.cpp.

References I.

Referenced by hoistValue(), and isHoistable().

negateICmpIfUsedByBranchOrSelectOnly()

static bool negateICmpIfUsedByBranchOrSelectOnly ( ICmpInst *  ICmp, Instruction *  ExcludedUser, CHRScope *  Scope  )

static

Definition at line 1539 of file ControlHeightReduction.cpp.

References assert(), llvm::CmpInst::getPredicate(), llvm_unreachable, llvm::CmpInst::setPredicate(), SI, and llvm::Value::users().

operator<<() [1/2]

static raw_ostream& operator<< ( raw_ostream &  OS, const CHRScope &  Scope  )

inlinestatic

Definition at line 435 of file ControlHeightReduction.cpp.

operator<<() [2/2]

static raw_ostream LLVM_ATTRIBUTE_UNUSED& operator<< ( raw_ostream &  OS, const CHRStats &  Stats  )

inlinestatic

Definition at line 428 of file ControlHeightReduction.cpp.

References Stats.

parseCHRFilterFiles()

static void parseCHRFilterFiles ( )

static

Definition at line 72 of file ControlHeightReduction.cpp.

References CHRFunctionList, CHRFunctions, CHRModuleList, CHRModules, llvm::errs(), exit(), llvm::MemoryBuffer::getFile(), llvm::StringSet< AllocatorTy >::insert(), and llvm::StringRef::split().

Referenced by llvm::ControlHeightReductionPass::ControlHeightReductionPass().

shouldApply()

static bool shouldApply ( Function &  F, ProfileSummaryInfo &  PSI  )

static

Definition at line 440 of file ControlHeightReduction.cpp.

References assert(), CHRFunctionList, CHRFunctions, CHRModuleList, CHRModules, llvm::StringMap< ValueTy, AllocatorTy >::count(), F, ForceCHR, llvm::ProfileSummaryInfo::hasProfileSummary(), and llvm::ProfileSummaryInfo::isFunctionEntryHot().

shouldSplit()

static bool shouldSplit ( Instruction *  InsertPoint, DenseSet< Value * > &  PrevConditionValues, DenseSet< Value * > &  ConditionValues, DominatorTree &  DT, DenseSet< Instruction * > &  Unhoistables  )

static

Definition at line 1076 of file ControlHeightReduction.cpp.

References assert(), checkHoistValue(), CHR_DEBUG, llvm::dbgs(), and getBaseValues().

Variable Documentation

chr

chr

Definition at line 138 of file ControlHeightReduction.cpp.

CHRBiasThreshold

cl::opt<double> CHRBiasThreshold("chr-bias-threshold", cl::init(0.99), cl::Hidden, cl::desc("CHR considers a branch bias greater than this ratio as biased"))

static

Referenced by getCHRBiasThreshold().

CHRFunctionList

cl::opt<std::string> CHRFunctionList("chr-function-list", cl::init(""), cl::Hidden, cl::desc("Specify file to retrieve the list of functions to apply CHR to"))

static

Referenced by parseCHRFilterFiles(), and shouldApply().

CHRFunctions

StringSet CHRFunctions

static

Definition at line 70 of file ControlHeightReduction.cpp.

Referenced by parseCHRFilterFiles(), and shouldApply().

CHRMergeThreshold

cl::opt<unsigned> CHRMergeThreshold("chr-merge-threshold", cl::init(2), cl::Hidden, cl::desc("CHR merges a group of N branches/selects where N >= this value"))

static

Referenced by hasAtLeastTwoBiasedBranches().

CHRModuleList

cl::opt<std::string> CHRModuleList("chr-module-list", cl::init(""), cl::Hidden, cl::desc("Specify file to retrieve the list of modules to apply CHR to"))

static

Referenced by parseCHRFilterFiles(), and shouldApply().

CHRModules

StringSet CHRModules

static

Definition at line 69 of file ControlHeightReduction.cpp.

Referenced by parseCHRFilterFiles(), and shouldApply().

false

Reduce control height in the hot false

Definition at line 140 of file ControlHeightReduction.cpp.

ForceCHR

cl::opt<bool> ForceCHR("force-chr", cl::init(false), cl::Hidden, cl::desc("Apply CHR for all functions"))

static

Referenced by shouldApply().

paths

Reduce control height in the hot paths

Definition at line 139 of file ControlHeightReduction.cpp.