This class represents a loop nest and can be used to query its properties. More...

#include "llvm/Analysis/LoopNestAnalysis.h"

Public Types
using	InstrVectorTy = SmallVector< const Instruction * >

Public Member Functions
	LoopNest (Loop &Root, ScalarEvolution &SE)
	Construct a loop nest rooted by loop `Root`.

	LoopNest ()=delete

Loop &	getOutermostLoop () const
	Return the outermost loop in the loop nest.

Loop *	getInnermostLoop () const
	Return the innermost loop in the loop nest if the nest has only one innermost loop, and a nullptr otherwise.

Loop *	getLoop (unsigned Index) const
	Return the loop at the given `Index`.

unsigned	getLoopIndex (const Loop &L) const
	Get the loop index of the given loop `L`.

size_t	getNumLoops () const
	Return the number of loops in the nest.

ArrayRef< Loop * >	getLoops () const
	Get the loops in the nest.

LoopVectorTy	getLoopsAtDepth (unsigned Depth) const
	Get the loops in the nest at the given `Depth`.

SmallVector< LoopVectorTy, 4 >	getPerfectLoops (ScalarEvolution &SE) const
	Retrieve a vector of perfect loop nests contained in the current loop nest.

unsigned	getNestDepth () const
	Return the loop nest depth (i.e.

unsigned	getMaxPerfectDepth () const
	Return the maximum perfect nesting depth.

bool	areAllLoopsSimplifyForm () const
	Return true if all loops in the loop nest are in simplify form.

bool	areAllLoopsRotatedForm () const
	Return true if all loops in the loop nest are in rotated form.

Function *	getParent () const
	Return the function to which the loop-nest belongs.

StringRef	getName () const

Static Public Member Functions
static std::unique_ptr< LoopNest >	getLoopNest (Loop &Root, ScalarEvolution &SE)
	Construct a LoopNest object.

static bool	arePerfectlyNested (const Loop &OuterLoop, const Loop &InnerLoop, ScalarEvolution &SE)
	Return true if the given loops `OuterLoop` and `InnerLoop` are perfectly nested with respect to each other, and false otherwise.

static InstrVectorTy	getInterveningInstructions (const Loop &OuterLoop, const Loop &InnerLoop, ScalarEvolution &SE)
	Return a vector of instructions that prevent the LoopNest given by loops `OuterLoop` and `InnerLoop` from being perfect.

static unsigned	getMaxPerfectDepth (const Loop &Root, ScalarEvolution &SE)
	Return the maximum nesting depth of the loop nest rooted by loop `Root`.

static const BasicBlock &	skipEmptyBlockUntil (const BasicBlock From, const BasicBlock End, bool CheckUniquePred=false)
	Recursivelly traverse all empty 'single successor' basic blocks of `From` (if there are any).

Protected Attributes
const unsigned	MaxPerfectDepth

LoopVectorTy	Loops

Detailed Description

This class represents a loop nest and can be used to query its properties.

Definition at line 28 of file LoopNestAnalysis.h.

Member Typedef Documentation

◆ InstrVectorTy

using llvm::LoopNest::InstrVectorTy = SmallVector<const Instruction *>

Definition at line 30 of file LoopNestAnalysis.h.

Constructor & Destructor Documentation

◆ LoopNest() [1/2]

LoopNest::LoopNest	(	Loop &	Root,
		ScalarEvolution &	SE
	)

Construct a loop nest rooted by loop Root.

Definition at line 42 of file LoopNestAnalysis.cpp.

References llvm::append_range(), llvm::breadth_first(), and Loops.

◆ LoopNest() [2/2]

llvm::LoopNest::LoopNest ( )

delete

Member Function Documentation

◆ areAllLoopsRotatedForm()

bool llvm::LoopNest::areAllLoopsRotatedForm ( ) const

inline

Return true if all loops in the loop nest are in rotated form.

Definition at line 171 of file LoopNestAnalysis.h.

References llvm::all_of(), and Loops.

◆ areAllLoopsSimplifyForm()

bool llvm::LoopNest::areAllLoopsSimplifyForm ( ) const

inline

Return true if all loops in the loop nest are in simplify form.

Definition at line 166 of file LoopNestAnalysis.h.

References llvm::all_of(), and Loops.

◆ arePerfectlyNested()

bool LoopNest::arePerfectlyNested	(	const Loop &	OuterLoop,
		const Loop &	InnerLoop,
		ScalarEvolution &	SE
	)

static

Return true if the given loops OuterLoop and InnerLoop are perfectly nested with respect to each other, and false otherwise.

Example:

for(i)
  for(j)
    for(k)

arePerfectlyNested(loop_i, loop_j, SE) would return true. arePerfectlyNested(loop_j, loop_k, SE) would return true. arePerfectlyNested(loop_i, loop_k, SE) would return false.

Definition at line 103 of file LoopNestAnalysis.cpp.

Referenced by getMaxPerfectDepth(), and getPerfectLoops().

◆ getInnermostLoop()

Loop * llvm::LoopNest::getInnermostLoop ( ) const

inline

Return the innermost loop in the loop nest if the nest has only one innermost loop, and a nullptr otherwise.

Note: the innermost loop returned is not necessarily perfectly nested.

Definition at line 85 of file LoopNestAnalysis.h.

References llvm::LoopBase< BlockT, LoopT >::getLoopDepth(), and Loops.

◆ getInterveningInstructions()

LoopNest::InstrVectorTy LoopNest::getInterveningInstructions	(	const Loop &	OuterLoop,
		const Loop &	InnerLoop,
		ScalarEvolution &	SE
	)

static

Return a vector of instructions that prevent the LoopNest given by loops OuterLoop and InnerLoop from being perfect.

Definition at line 181 of file LoopNestAnalysis.cpp.

References checkSafeInstruction(), llvm::dbgs(), DEBUG_WITH_TYPE, llvm::Loop::getBounds(), llvm::LoopBase< BlockT, LoopT >::getExitBlock(), llvm::LoopBase< BlockT, LoopT >::getHeader(), getInnerLoopGuardCmp(), llvm::LoopBase< BlockT, LoopT >::getLoopLatch(), llvm::LoopBase< BlockT, LoopT >::getLoopPreheader(), getOuterLoopLatchCmp(), I, LLVM_DEBUG, and VerboseDebug.

◆ getLoop()

Loop * llvm::LoopNest::getLoop ( unsigned Index ) const

inline

Return the loop at the given Index.

Definition at line 100 of file LoopNestAnalysis.h.

References assert(), Index, and Loops.

◆ getLoopIndex()

unsigned llvm::LoopNest::getLoopIndex ( const Loop & L ) const

inline

Get the loop index of the given loop L.

Definition at line 106 of file LoopNestAnalysis.h.

References I, and llvm_unreachable.

◆ getLoopNest()

std::unique_ptr< LoopNest > LoopNest::getLoopNest	(	Loop &	Root,
		ScalarEvolution &	SE
	)

static

Construct a LoopNest object.

Definition at line 47 of file LoopNestAnalysis.cpp.

Referenced by llvm::LoopNestPrinterPass::run(), and llvm::PassManager< Loop, LoopAnalysisManager, LoopStandardAnalysisResults &, LPMUpdater & >::runWithLoopNestPasses().

◆ getLoops()

ArrayRef< Loop * > llvm::LoopNest::getLoops ( ) const

inline

Get the loops in the nest.

Definition at line 117 of file LoopNestAnalysis.h.

References Loops.

Referenced by llvm::operator<<(), llvm::LoopInterchangePass::run(), llvm::LoopFlattenPass::run(), and tryToUnrollAndJamLoop().

◆ getLoopsAtDepth()

LoopVectorTy llvm::LoopNest::getLoopsAtDepth ( unsigned Depth ) const

inline

Get the loops in the nest at the given Depth.

Definition at line 120 of file LoopNestAnalysis.h.

References assert(), llvm::Depth, I, and Loops.

◆ getMaxPerfectDepth() [1/2]

unsigned llvm::LoopNest::getMaxPerfectDepth ( ) const

inline

Return the maximum perfect nesting depth.

Definition at line 163 of file LoopNestAnalysis.h.

◆ getMaxPerfectDepth() [2/2]

unsigned LoopNest::getMaxPerfectDepth	(	const Loop &	Root,
		ScalarEvolution &	SE
	)

static

Return the maximum nesting depth of the loop nest rooted by loop Root.

For example given the loop nest:

for(i)     // loop at level 1 and Root of the nest
  for(j)   // loop at level 2
    <code>
    for(k) // loop at level 3

getMaxPerfectDepth(Loop_i) would return 2.

Definition at line 261 of file LoopNestAnalysis.cpp.

References arePerfectlyNested(), llvm::dbgs(), llvm::Loop::getName(), llvm::LoopBase< BlockT, LoopT >::getSubLoops(), and LLVM_DEBUG.

Referenced by llvm::operator<<().

◆ getName()

StringRef llvm::LoopNest::getName ( ) const

inline

Definition at line 180 of file LoopNestAnalysis.h.

References Loops.

◆ getNestDepth()

unsigned llvm::LoopNest::getNestDepth ( ) const

inline

Return the loop nest depth (i.e.

the loop depth of the 'deepest' loop) For example given the loop nest:

for(i)      // loop at level 1 and Root of the nest
  for(j1)   // loop at level 2
    for(k)  // loop at level 3
  for(j2)   // loop at level 2

getNestDepth() would return 3.

Definition at line 155 of file LoopNestAnalysis.h.

References assert(), and Loops.

Referenced by llvm::operator<<().

◆ getNumLoops()

size_t llvm::LoopNest::getNumLoops ( ) const

inline

Return the number of loops in the nest.

Definition at line 114 of file LoopNestAnalysis.h.

References Loops.

◆ getOutermostLoop()

Loop & llvm::LoopNest::getOutermostLoop ( ) const

inline

Return the outermost loop in the loop nest.

Definition at line 80 of file LoopNestAnalysis.h.

References Loops.

Referenced by llvm::operator<<(), llvm::LNICMPass::run(), llvm::LoopInterchangePass::run(), and tryToUnrollAndJamLoop().

◆ getParent()

Function * llvm::LoopNest::getParent ( ) const

inline

Return the function to which the loop-nest belongs.

Definition at line 176 of file LoopNestAnalysis.h.

References Loops.

Referenced by llvm::LNICMPass::run(), llvm::LoopInterchangePass::run(), and llvm::LoopUnrollAndJamPass::run().

◆ getPerfectLoops()

SmallVector< LoopVectorTy, 4 > LoopNest::getPerfectLoops ( ScalarEvolution & SE ) const

Retrieve a vector of perfect loop nests contained in the current loop nest.

For example, given the following nest containing 4 loops, this member function would return {{L1,L2},{L3,L4}}.

for(i) // L1
  for(j) // L2
    <code>
    for(k) // L3
      for(l) // L4

Definition at line 241 of file LoopNestAnalysis.cpp.

References arePerfectlyNested(), llvm::SmallVectorImpl< T >::clear(), llvm::depth_first(), llvm::SmallVectorBase< Size_T >::empty(), llvm::SmallVectorTemplateCommon< T, typename >::front(), Loops, and llvm::SmallVectorTemplateBase< T, bool >::push_back().

◆ skipEmptyBlockUntil()

const BasicBlock & LoopNest::skipEmptyBlockUntil	(	const BasicBlock *	From,
		const BasicBlock *	End,
		bool	CheckUniquePred = `false`
	)

static

Recursivelly traverse all empty 'single successor' basic blocks of From (if there are any).

When CheckUniquePred is set to true, check if each of the empty single successors has a unique predecessor. Return the last basic block found or End if it was reached during the search.

Definition at line 288 of file LoopNestAnalysis.cpp.

References assert(), llvm::SmallPtrSetImpl< PtrType >::count(), End, From, llvm::BasicBlock::getUniquePredecessor(), llvm::BasicBlock::getUniqueSuccessor(), and llvm::SmallPtrSetImpl< PtrType >::insert().

Referenced by llvm::Loop::getLoopGuardBranch().

Member Data Documentation

◆ Loops

LoopVectorTy llvm::LoopNest::Loops

protected

Definition at line 184 of file LoopNestAnalysis.h.

Referenced by getPerfectLoops(), and LoopNest().

◆ MaxPerfectDepth

const unsigned llvm::LoopNest::MaxPerfectDepth

protected

Definition at line 183 of file LoopNestAnalysis.h.

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

include/llvm/Analysis/LoopNestAnalysis.h
lib/Analysis/LoopNestAnalysis.cpp

Public Types

Public Member Functions

Static Public Member Functions

Protected Attributes

Detailed Description

Member Typedef Documentation

◆ InstrVectorTy

Constructor & Destructor Documentation

◆ LoopNest() [1/2]

◆ LoopNest() [2/2]

Member Function Documentation

◆ areAllLoopsRotatedForm()

◆ areAllLoopsSimplifyForm()

◆ arePerfectlyNested()

◆ getInnermostLoop()

◆ getInterveningInstructions()

◆ getLoop()

◆ getLoopIndex()

◆ getLoopNest()

◆ getLoops()

◆ getLoopsAtDepth()

◆ getMaxPerfectDepth() [1/2]

◆ getMaxPerfectDepth() [2/2]

◆ getName()

◆ getNestDepth()

◆ getNumLoops()

◆ getOutermostLoop()

◆ getParent()

◆ getPerfectLoops()

◆ skipEmptyBlockUntil()

Member Data Documentation

◆ Loops

◆ MaxPerfectDepth