#include <LoopInfo.h>

Inheritance diagram for llvm::Loop:

Collaboration diagram for llvm::Loop:

Public Member Functions
	Loop ()
bool	isLoopInvariant (Value *V) const
bool	hasLoopInvariantOperands (Instruction *I) const
bool	makeLoopInvariant (Value V, bool &Changed, Instruction InsertPt=nullptr) const
bool	makeLoopInvariant (Instruction I, bool &Changed, Instruction InsertPt=nullptr) const
PHINode *	getCanonicalInductionVariable () const
bool	isLCSSAForm (DominatorTree &DT) const
	isLCSSAForm - Return true if the Loop is in LCSSA form
bool	isLoopSimplifyForm () const
bool	isSafeToClone () const
	isSafeToClone - Return true if the loop body is safe to clone in practice.
bool	isAnnotatedParallel () const
MDNode *	getLoopID () const
void	setLoopID (MDNode *LoopID) const
bool	hasDedicatedExits () const
void	getUniqueExitBlocks (SmallVectorImpl< BasicBlock * > &ExitBlocks) const
BasicBlock *	getUniqueExitBlock () const
void	dump () const
DebugLoc	getStartLoc () const
	Return the debug location of the start of this loop. This looks for a BB terminating instruction with a known debug location by looking at the preheader and header blocks. If it cannot find a terminating instruction with location information, it returns an unknown location.
Friends
class	LoopInfoBase< BasicBlock, Loop >

Detailed Description

Definition at line 353 of file LoopInfo.h.

Constructor & Destructor Documentation

llvm::Loop::Loop ( ) [inline]

Definition at line 355 of file LoopInfo.h.

Member Function Documentation

void Loop::dump ( ) const

Definition at line 409 of file LoopInfo.cpp.

References llvm::dbgs(), and llvm::LoopBase< BasicBlock, Loop >::print().

PHINode * Loop::getCanonicalInductionVariable ( ) const

getCanonicalInductionVariable - Check to see if the loop has a canonical induction variable: an integer recurrence that starts at 0 and increments by one each time through the loop. If so, return the phi node that corresponds to it.

The IndVarSimplify pass transforms loops to have a canonical induction variable.

Definition at line 141 of file LoopInfo.cpp.

References llvm::BasicBlock::begin(), llvm::LoopBase< BasicBlock, Loop >::contains(), llvm::LoopBase< BasicBlock, Loop >::getHeader(), llvm::PHINode::getIncomingValueForBlock(), H, I, llvm::pred_begin(), llvm::pred_end(), and std::swap().

MDNode * Loop::getLoopID ( ) const

Return the llvm.loop loop id metadata node for this loop if it is present.

If this loop contains the same llvm.loop metadata on each branch to the header then the node is returned. If any latch instruction does not contain llvm.loop or or if multiple latches contain different nodes then 0 is returned.

Definition at line 234 of file LoopInfo.cpp.

References llvm::LoopBase< BasicBlock, Loop >::block_begin(), llvm::LoopBase< BasicBlock, Loop >::block_end(), llvm::LoopBase< BasicBlock, Loop >::getHeader(), llvm::LoopBase< BasicBlock, Loop >::getLoopLatch(), llvm::Instruction::getMetadata(), llvm::MDNode::getNumOperands(), llvm::TerminatorInst::getNumSuccessors(), llvm::MDNode::getOperand(), llvm::TerminatorInst::getSuccessor(), llvm::BasicBlock::getTerminator(), H, I, llvm::ARM_PROC::IE, isLoopSimplifyForm(), and LoopMDName.

Referenced by GetUnrollMetadata(), isAnnotatedParallel(), and SetLoopAlreadyUnrolled().

DebugLoc llvm::Loop::getStartLoc ( ) const [inline]

Return the debug location of the start of this loop. This looks for a BB terminating instruction with a known debug location by looking at the preheader and header blocks. If it cannot find a terminating instruction with location information, it returns an unknown location.

Definition at line 461 of file LoopInfo.h.

References llvm::Instruction::getDebugLoc(), llvm::BasicBlock::getTerminator(), and llvm::DebugLoc::isUnknown().

Referenced by llvm::UnrollLoop().

BasicBlock * Loop::getUniqueExitBlock ( ) const

getUniqueExitBlock - If getUniqueExitBlocks would return exactly one block, return that block. Otherwise return null.

Definition at line 400 of file LoopInfo.cpp.

References getUniqueExitBlocks(), and llvm::SmallVectorTemplateCommon< T >::size().

Referenced by ConnectProlog(), and llvm::UnrollRuntimeLoopProlog().

void Loop::getUniqueExitBlocks ( SmallVectorImpl< BasicBlock * > & ExitBlocks ) const

getUniqueExitBlocks - Return all unique successor blocks of this loop. These are the blocks _outside of the current loop_ which are branched to. This assumes that loop exits are in canonical form.

Definition at line 352 of file LoopInfo.cpp.

References llvm::SmallVectorTemplateCommon< T >::begin(), llvm::LoopBase< BasicBlock, Loop >::block_begin(), llvm::LoopBase< BasicBlock, Loop >::block_end(), llvm::SmallVectorImpl< T >::clear(), llvm::LoopBase< BasicBlock, Loop >::contains(), llvm::SmallVectorTemplateCommon< T >::end(), hasDedicatedExits(), I, llvm::pred_begin(), llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::SmallVectorTemplateBase< T, isPodLike >::push_back(), llvm::succ_begin(), and llvm::succ_end().

Referenced by getUniqueExitBlock().

bool Loop::hasDedicatedExits ( ) const

hasDedicatedExits - Return true if no exit block for the loop has a predecessor that is outside the loop.

Definition at line 333 of file LoopInfo.cpp.

References llvm::LoopBase< BasicBlock, Loop >::contains(), llvm::LoopBase< BasicBlock, Loop >::getExitBlocks(), llvm::pred_begin(), llvm::pred_end(), and llvm::SmallVectorTemplateCommon< T >::size().

Referenced by getUniqueExitBlocks(), and isLoopSimplifyForm().

bool Loop::hasLoopInvariantOperands ( Instruction * I ) const

hasLoopInvariantOperands - Return true if all the operands of the specified instruction are loop invariant.

Definition at line 69 of file LoopInfo.cpp.

References llvm::User::getNumOperands(), llvm::User::getOperand(), and isLoopInvariant().

bool Loop::isAnnotatedParallel ( ) const

Returns true if the loop is annotated parallel.

A parallel loop can be assumed to not contain any dependencies between iterations by the compiler. That is, any loop-carried dependency checking can be skipped completely when parallelizing the loop on the target machine. Thus, if the parallel loop information originates from the programmer, e.g. via the OpenMP parallel for pragma, it is the programmer's responsibility to ensure there are no loop-carried dependencies. The final execution order of the instructions across iterations is not guaranteed, thus, the end result might or might not implement actual concurrent execution of instructions across multiple iterations.

Definition at line 288 of file LoopInfo.cpp.

References llvm::LoopBase< BasicBlock, Loop >::block_begin(), llvm::LoopBase< BasicBlock, Loop >::block_end(), getLoopID(), llvm::MDNode::getNumOperands(), and llvm::MDNode::getOperand().

bool Loop::isLCSSAForm ( DominatorTree & DT ) const

isLCSSAForm - Return true if the Loop is in LCSSA form

Definition at line 178 of file LoopInfo.cpp.

References llvm::BasicBlock::begin(), llvm::LoopBase< BasicBlock, Loop >::block_begin(), llvm::LoopBase< BasicBlock, Loop >::block_end(), llvm::LoopBase< BasicBlock, Loop >::contains(), llvm::BasicBlock::end(), llvm::Instruction::getParent(), I, llvm::DominatorTree::isReachableFromEntry(), and P.

Referenced by llvm::formLCSSA().

bool Loop::isLoopInvariant ( Value * V ) const

isLoopInvariant - Return true if the specified value is loop invariant

Definition at line 61 of file LoopInfo.cpp.

References contains(), and I.

Referenced by getStrideFromPointer(), hasLoopInvariantOperands(), and makeLoopInvariant().

bool Loop::isLoopSimplifyForm ( ) const

isLoopSimplifyForm - Return true if the Loop is in the form that the LoopSimplify form transforms loops to, which is sometimes called normal form.

Definition at line 205 of file LoopInfo.cpp.

References llvm::LoopBase< BasicBlock, Loop >::getLoopLatch(), llvm::LoopBase< BasicBlock, Loop >::getLoopPreheader(), and hasDedicatedExits().

Referenced by getLoopID(), isSimplifiedLoopNest(), setLoopID(), and llvm::UnrollRuntimeLoopProlog().

bool Loop::isSafeToClone ( ) const

isSafeToClone - Return true if the loop body is safe to clone in practice.

isSafeToClone - Return true if the loop body is safe to clone in practice. Routines that reform the loop CFG and split edges often fail on indirectbr.

Definition at line 213 of file LoopInfo.cpp.

References llvm::LoopBase< BasicBlock, Loop >::block_begin(), llvm::LoopBase< BasicBlock, Loop >::block_end(), and I.

Referenced by llvm::UnrollLoop().

bool Loop::makeLoopInvariant	(	Value *	V,
		bool &	Changed,
		Instruction *	InsertPt = `nullptr`
	)		const

makeLoopInvariant - If the given value is an instruction inside of the loop and it can be hoisted, do so to make it trivially loop-invariant. Return true if the value after any hoisting is loop invariant. This function can be used as a slightly more aggressive replacement for isLoopInvariant.

If InsertPt is specified, it is the point to hoist instructions to. If null, the terminator of the loop preheader is used.

makeLoopInvariant - If the given value is an instruciton inside of the loop and it can be hoisted, do so to make it trivially loop-invariant. Return true if the value after any hoisting is loop invariant. This function can be used as a slightly more aggressive replacement for isLoopInvariant.

If InsertPt is specified, it is the point to hoist instructions to. If null, the terminator of the loop preheader is used.

Definition at line 86 of file LoopInfo.cpp.

References I.

Referenced by FindLIVLoopCondition(), makeLoopInvariant(), and simplifyOneLoop().

bool Loop::makeLoopInvariant	(	Instruction *	I,
		bool &	Changed,
		Instruction *	InsertPt = `nullptr`
	)		const

makeLoopInvariant - If the given instruction is inside of the loop and it can be hoisted, do so to make it trivially loop-invariant. Return true if the instruction after any hoisting is loop invariant. This function can be used as a slightly more aggressive replacement for isLoopInvariant.

If InsertPt is specified, it is the point to hoist instructions to. If null, the terminator of the loop preheader is used.

Definition at line 102 of file LoopInfo.cpp.

References llvm::LoopBase< BasicBlock, Loop >::getLoopPreheader(), llvm::User::getNumOperands(), llvm::User::getOperand(), llvm::BasicBlock::getTerminator(), isLoopInvariant(), llvm::isSafeToSpeculativelyExecute(), makeLoopInvariant(), llvm::Instruction::mayReadFromMemory(), and llvm::Instruction::moveBefore().