Represents a single loop in the control flow graph. More...
#include "llvm/Analysis/LoopInfo.h"
Classes | |
| class | LocRange |
| A range representing the start and end location of a loop. More... | |
Public Member Functions | |
| bool | isLoopInvariant (const Value *V) const |
| Return true if the specified value is loop invariant. More... | |
| bool | hasLoopInvariantOperands (const Instruction *I) const |
| Return true if all the operands of the specified instruction are loop invariant. More... | |
| bool | makeLoopInvariant (Value *V, bool &Changed, Instruction *InsertPt=nullptr) const |
| If the given value is an instruction inside of the loop and it can be hoisted, do so to make it trivially loop-invariant. More... | |
| bool | makeLoopInvariant (Instruction *I, bool &Changed, Instruction *InsertPt=nullptr) const |
| If the given instruction is inside of the loop and it can be hoisted, do so to make it trivially loop-invariant. More... | |
| PHINode * | getCanonicalInductionVariable () const |
| 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. More... | |
| bool | isLCSSAForm (DominatorTree &DT) const |
| Return true if the Loop is in LCSSA form. More... | |
| bool | isRecursivelyLCSSAForm (DominatorTree &DT, const LoopInfo &LI) const |
| Return true if this Loop and all inner subloops are in LCSSA form. More... | |
| bool | isLoopSimplifyForm () const |
| Return true if the Loop is in the form that the LoopSimplify form transforms loops to, which is sometimes called normal form. More... | |
| bool | isSafeToClone () const |
| Return true if the loop body is safe to clone in practice. More... | |
| bool | isAnnotatedParallel () const |
| Returns true if the loop is annotated parallel. More... | |
| MDNode * | getLoopID () const |
| Return the llvm.loop loop id metadata node for this loop if it is present. More... | |
| void | setLoopID (MDNode *LoopID) const |
| Set the llvm.loop loop id metadata for this loop. More... | |
| void | setLoopAlreadyUnrolled () |
| Add llvm.loop.unroll.disable to this loop's loop id metadata. More... | |
| void | dump () const |
| void | dumpVerbose () const |
| DebugLoc | getStartLoc () const |
| Return the debug location of the start of this loop. More... | |
| LocRange | getLocRange () const |
| Return the source code span of the loop. More... | |
| StringRef | getName () const |
 Public Member Functions inherited from llvm::LoopBase< BasicBlock, Loop > | |
| unsigned | getLoopDepth () const |
| Return the nesting level of this loop. More... | |
| BasicBlock * | getHeader () const |
| Loop * | getParentLoop () const |
| void | setParentLoop (Loop *L) |
| This is a raw interface for bypassing addChildLoop. More... | |
| bool | contains (const Loop *L) const |
| Return true if the specified loop is contained within in this loop. More... | |
| bool | contains (const BasicBlock *BB) const |
| Return true if the specified basic block is in this loop. More... | |
| bool | contains (const InstT *Inst) const |
| Return true if the specified instruction is in this loop. More... | |
| const std::vector< Loop *> & | getSubLoops () const |
| Return the loops contained entirely within this loop. More... | |
| std::vector< Loop *> & | getSubLoopsVector () |
| iterator | begin () const |
| iterator | end () const |
| reverse_iterator | rbegin () const |
| reverse_iterator | rend () const |
| bool | empty () const |
| ArrayRef< BasicBlock *> | getBlocks () const |
| Get a list of the basic blocks which make up this loop. More... | |
| block_iterator | block_begin () const |
| block_iterator | block_end () const |
| iterator_range< block_iterator > | blocks () const |
| unsigned | getNumBlocks () const |
| Get the number of blocks in this loop in constant time. More... | |
| std::vector< BasicBlock *> & | getBlocksVector () |
Return a direct, mutable handle to the blocks vector so that we can mutate it efficiently with techniques like std::remove. More... | |
| SmallPtrSetImpl< const BasicBlock *> & | getBlocksSet () |
| Return a direct, mutable handle to the blocks set so that we can mutate it efficiently. More... | |
| const SmallPtrSetImpl< const BasicBlock *> & | getBlocksSet () const |
| Return a direct, immutable handle to the blocks set. More... | |
| bool | isInvalid () const |
| Return true if this loop is no longer valid. More... | |
| bool | isLoopExiting (const BasicBlock *BB) const |
| True if terminator in the block can branch to another block that is outside of the current loop. More... | |
| bool | isLoopLatch (const BasicBlock *BB) const |
| unsigned | getNumBackEdges () const |
| Calculate the number of back edges to the loop header. More... | |
| void | getExitingBlocks (SmallVectorImpl< BasicBlock * > &ExitingBlocks) const |
| Return all blocks inside the loop that have successors outside of the loop. More... | |
| BasicBlock * | getExitingBlock () const |
| If getExitingBlocks would return exactly one block, return that block. More... | |
| void | getExitBlocks (SmallVectorImpl< BasicBlock * > &ExitBlocks) const |
| Return all of the successor blocks of this loop. More... | |
| BasicBlock * | getExitBlock () const |
| If getExitBlocks would return exactly one block, return that block. More... | |
| bool | hasDedicatedExits () const |
| Return true if no exit block for the loop has a predecessor that is outside the loop. More... | |
| void | getUniqueExitBlocks (SmallVectorImpl< BasicBlock * > &ExitBlocks) const |
| Return all unique successor blocks of this loop. More... | |
| BasicBlock * | getUniqueExitBlock () const |
| If getUniqueExitBlocks would return exactly one block, return that block. More... | |
| void | getExitEdges (SmallVectorImpl< Edge > &ExitEdges) const |
| Return all pairs of (inside_block,outside_block). More... | |
| BasicBlock * | getLoopPreheader () const |
| If there is a preheader for this loop, return it. More... | |
| BasicBlock * | getLoopPredecessor () const |
| If the given loop's header has exactly one unique predecessor outside the loop, return it. More... | |
| BasicBlock * | getLoopLatch () const |
| If there is a single latch block for this loop, return it. More... | |
| void | getLoopLatches (SmallVectorImpl< BasicBlock * > &LoopLatches) const |
| Return all loop latch blocks of this loop. More... | |
| void | addBasicBlockToLoop (BasicBlock *NewBB, LoopInfoBase< BasicBlock, Loop > &LI) |
| This method is used by other analyses to update loop information. More... | |
| void | replaceChildLoopWith (Loop *OldChild, Loop *NewChild) |
| This is used when splitting loops up. More... | |
| void | addChildLoop (Loop *NewChild) |
| Add the specified loop to be a child of this loop. More... | |
| Loop * | removeChildLoop (iterator I) |
| This removes the specified child from being a subloop of this loop. More... | |
| Loop * | removeChildLoop (Loop *Child) |
| This removes the specified child from being a subloop of this loop. More... | |
| void | addBlockEntry (BasicBlock *BB) |
| This adds a basic block directly to the basic block list. More... | |
| void | reverseBlock (unsigned from) |
| interface to reverse Blocks[from, end of loop] in this loop More... | |
| void | reserveBlocks (unsigned size) |
| interface to do reserve() for Blocks More... | |
| void | moveToHeader (BasicBlock *BB) |
| This method is used to move BB (which must be part of this loop) to be the loop header of the loop (the block that dominates all others). More... | |
| void | removeBlockFromLoop (BasicBlock *BB) |
| This removes the specified basic block from the current loop, updating the Blocks as appropriate. More... | |
| void | verifyLoop () const |
| Verify loop structure. More... | |
| void | verifyLoopNest (DenseSet< const Loop * > *Loops) const |
| Verify loop structure of this loop and all nested loops. More... | |
| bool | isAnnotatedParallel () const |
| Returns true if the loop is annotated parallel. More... | |
| void | print (raw_ostream &OS, unsigned Depth=0, bool Verbose=false) const |
| Print loop with all the BBs inside it. More... | |
Friends | |
| class | LoopInfoBase< BasicBlock, Loop > |
| class | LoopBase< BasicBlock, Loop > |
Additional Inherited Members | |
| Public Types inherited from llvm::LoopBase< BasicBlock, Loop > | |
| typedef std::vector< Loop *>::const_iterator | iterator |
| typedef std::vector< Loop *>::const_reverse_iterator | reverse_iterator |
| typedef ArrayRef< BasicBlock *>::const_iterator | block_iterator |
| typedef std::pair< const BasicBlock *, const BasicBlock *> | Edge |
| Edge type. More... | |
| Protected Member Functions inherited from llvm::LoopBase< BasicBlock, Loop > | |
| LoopBase () | |
| This creates an empty loop. More... | |
| LoopBase (BasicBlock *BB) | |
| ~LoopBase () | |
Detailed Description
Represents a single loop in the control flow graph.
Note that not all SCCs in the CFG are necessarily loops.
Definition at line 465 of file LoopInfo.h.
Member Function Documentation
◆ dump()
| LLVM_DUMP_METHOD void Loop::dump | ( | ) | const |
Definition at line 401 of file LoopInfo.cpp.
References llvm::dbgs(), and llvm::LoopBase< BasicBlock, Loop >::print().
Referenced by CheckMACMemory(), llvm::createLoopDeletionPass(), llvm::LoopDeletionPass::run(), shouldRotateLoopExitingLatch(), and llvm::UnrollRuntimeLoopRemainder().
◆ dumpVerbose()
| LLVM_DUMP_METHOD void Loop::dumpVerbose | ( | ) | const |
Definition at line 403 of file LoopInfo.cpp.
References assert(), llvm::LoopBase< BlockT, LoopT >::contains(), llvm::dbgs(), DFS(), E, first, llvm::LoopBase< BlockT, LoopT >::getParentLoop(), I, llvm::LoopInfo::LoopInfo(), llvm::LoopBase< BasicBlock, Loop >::print(), llvm::LoopBase< BlockT, LoopT >::removeChildLoop(), llvm::succ_begin(), and llvm::succ_end().
◆ getCanonicalInductionVariable()
| PHINode * Loop::getCanonicalInductionVariable | ( | ) | const |
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 113 of file LoopInfo.cpp.
References llvm::MCID::Add, assert(), 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().
Referenced by getInductionVariable(), and llvm::isUniformLoop().
◆ getLocRange()
| Loop::LocRange Loop::getLocRange | ( | ) | const |
Return the source code span of the loop.
Definition at line 367 of file LoopInfo.cpp.
References getLoopID().
Referenced by getStartLoc().
◆ getLoopID()
| 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 if multiple latches contain different nodes then 0 is returned.
Definition at line 215 of file LoopInfo.cpp.
References llvm::LoopBase< BasicBlock, Loop >::getLoopLatches(), llvm::Instruction::getMetadata(), llvm::MDNode::getNumOperands(), llvm::MDNode::getOperand(), and llvm::LLVMContext::MD_loop.
Referenced by AddRuntimeUnrollDisableMetaData(), llvm::addStringMetadataToLoop(), CloneLoopBlocks(), llvm::InnerLoopVectorizer::createVectorizedLoopSkeleton(), llvm::findOptionMDForLoop(), getLocRange(), GetUnrollMetadataForLoop(), HasAnyUnrollPragma(), isAnnotatedParallel(), llvm::LoopVectorizePass::processLoop(), setLoopAlreadyUnrolled(), tryToUnrollAndJamLoop(), and tryToUnrollLoop().
◆ getName()
|
inline |
Definition at line 589 of file LoopInfo.h.
References llvm::LoopBase< BlockT, LoopT >::getHeader().
Referenced by asmClobbersCTR(), llvm::DivergenceAnalysis::inRegion(), llvm::LoopDeletionPass::run(), llvm::SimpleLoopUnswitchPass::run(), llvm::LoopUnrollPass::run(), and llvm::LPPassManager::runOnFunction().
◆ getStartLoc()
| DebugLoc Loop::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.
Definition at line 365 of file LoopInfo.cpp.
References getLocRange(), and llvm::Loop::LocRange::getStart().
Referenced by llvm::LoopVectorizeHints::allowVectorization(), areLoopExitPHIsSupported(), llvm::LoopAccessInfo::blockNeedsPredication(), llvm::computeUnrollCount(), containsSafePHI(), llvm::createLVMissedAnalysis(), llvm::LoopVectorizationRequirements::doesNotMeet(), getDebugLocString(), getInductionVariable(), isProfitableForVectorization(), llvm::LoopVectorizePass::processLoop(), llvm::UnrollAndJamLoop(), llvm::UnrollLoop(), and warnAboutLeftoverTransformations().
◆ hasLoopInvariantOperands()
| bool Loop::hasLoopInvariantOperands | ( | const Instruction * | I | ) | const |
Return true if all the operands of the specified instruction are loop invariant.
Definition at line 64 of file LoopInfo.cpp.
References llvm::all_of(), isLoopInvariant(), and llvm::User::operands().
Referenced by ConvertToSInt(), llvm::hoistRegion(), shouldRotateLoopExitingLatch(), sinkLoopInvariantInstructions(), llvm::sinkRegion(), and llvm::InnerLoopVectorizer::widenInstruction().
◆ isAnnotatedParallel()
| 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 290 of file LoopInfo.cpp.
References assert(), llvm::LoopBase< BasicBlock, Loop >::blocks(), llvm::SmallPtrSetImpl< PtrType >::count(), llvm::drop_begin(), llvm::findOptionMDForLoop(), getLoopID(), I, llvm::SmallPtrSetImpl< PtrType >::insert(), llvm::isValidAsAccessGroup(), llvm::LLVMContext::MD_access_group, llvm::LLVMContext::MD_mem_parallel_loop_access, and llvm::MDNode::operands().
Referenced by llvm::MemoryDepChecker::Dependence::print().
◆ isLCSSAForm()
| bool Loop::isLCSSAForm | ( | DominatorTree & | DT | ) | const |
Return true if the Loop is in LCSSA form.
Definition at line 177 of file LoopInfo.cpp.
References llvm::all_of(), llvm::LoopBase< BasicBlock, Loop >::blocks(), and isBlockInLCSSAForm().
Referenced by analyzeLoopUnrollCost(), ConvertToSInt(), llvm::createLICMPass(), llvm::deleteDeadLoop(), deleteLoopIfDead(), FindLIVLoopCondition(), llvm::formLCSSA(), and llvm::UnrollLoop().
◆ isLoopInvariant()
Return true if the specified value is loop invariant.
Definition at line 58 of file LoopInfo.cpp.
References llvm::LoopBase< BasicBlock, Loop >::contains(), and I.
Referenced by llvm::PredicatedScalarEvolution::areAddRecsEqualWithPreds(), areLoopExitPHIsLoopInvariant(), calculateIterationsToInvariance(), llvm::canSinkOrHoistInst(), collectHomogenousInstGraphLoopInvariants(), ConvertToSInt(), llvm::createFalkorMarkStridedAccessesPass(), llvm::createLICMPass(), llvm::createSeparateConstOffsetFromGEPPass(), llvm::InnerLoopVectorizer::fixFirstOrderRecurrence(), llvm::InnerLoopVectorizer::getBroadcastInstrs(), getFalkorUnrollingPreferences(), getInductionVariable(), llvm::InnerLoopVectorizer::getOrCreateScalarValue(), GetPointerOperand(), llvm::getStrideFromPointer(), llvm::AMDGPUTTIImpl::getUnrollingPreferences(), hasLoopInvariantOperands(), llvm::hoistRegion(), isSafeToExecuteUnconditionally(), isSameUnderlyingObjectInLoop(), llvm::isUniformLoop(), makeLoopInvariant(), llvm::LoopDataPrefetchPass::run(), unswitchBestCondition(), unswitchTrivialBranch(), unswitchTrivialSwitch(), and llvm::InnerLoopVectorizer::widenInstruction().
◆ isLoopSimplifyForm()
| bool Loop::isLoopSimplifyForm | ( | ) | const |
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 193 of file LoopInfo.cpp.
References llvm::LoopBase< BasicBlock, Loop >::getLoopLatch(), llvm::LoopBase< BasicBlock, Loop >::getLoopPreheader(), and llvm::LoopBase< BasicBlock, Loop >::hasDedicatedExits().
Referenced by analyzeLoopUnrollCost(), llvm::canPeel(), countToEliminateCompares(), INITIALIZE_PASS(), isLoadConditional(), llvm::isSafeToUnrollAndJam(), isSimplifiedLoopNest(), llvm::LoopVersioning::LoopVersioning(), mayUsePostIncMode(), ReduceLoopStrength(), tryToUnrollAndJamLoop(), tryToUnrollLoop(), llvm::UnrollAndJamLoop(), llvm::UnrollRuntimeLoopRemainder(), and unswitchLoop().
◆ isRecursivelyLCSSAForm()
| bool Loop::isRecursivelyLCSSAForm | ( | DominatorTree & | DT, |
| const LoopInfo & | LI | ||
| ) | const |
Return true if this Loop and all inner subloops are in LCSSA form.
Definition at line 184 of file LoopInfo.cpp.
References llvm::all_of(), llvm::LoopBase< BasicBlock, Loop >::blocks(), llvm::LoopInfoBase< BlockT, LoopT >::getLoopFor(), and isBlockInLCSSAForm().
Referenced by ConvertToSInt(), llvm::createLoopSimplifyPass(), formLCSSAOnAllLoops(), llvm::FunctionToLoopPassAdaptor< LoopPassT >::run(), llvm::LPPassManager::runOnFunction(), separateNestedLoop(), llvm::simplifyLoop(), llvm::UnrollAndJamLoop(), and unswitchLoop().
◆ isSafeToClone()
| bool Loop::isSafeToClone | ( | ) | const |
Return true if the loop body is safe to clone in practice.
Definition at line 200 of file LoopInfo.cpp.
References llvm::LoopBase< BasicBlock, Loop >::blocks(), and I.
Referenced by EqualityPropUnSafe(), and llvm::UnrollLoop().
◆ makeLoopInvariant() [1/2]
| bool Loop::makeLoopInvariant | ( | Value * | V, |
| bool & | Changed, | ||
| Instruction * | InsertPt = nullptr |
||
| ) | const |
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.
Definition at line 68 of file LoopInfo.cpp.
References I.
Referenced by FindLIVLoopCondition(), isLoopDead(), makeLoopInvariant(), and simplifyOneLoop().
◆ makeLoopInvariant() [2/2]
| bool Loop::makeLoopInvariant | ( | Instruction * | I, |
| bool & | Changed, | ||
| Instruction * | InsertPt = nullptr |
||
| ) | const |
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 75 of file LoopInfo.cpp.
References llvm::Instruction::dropUnknownNonDebugMetadata(), llvm::LoopBase< BasicBlock, Loop >::getLoopPreheader(), llvm::BasicBlock::getTerminator(), llvm::Instruction::isEHPad(), isLoopInvariant(), llvm::isSafeToSpeculativelyExecute(), makeLoopInvariant(), llvm::Instruction::mayReadFromMemory(), llvm::Instruction::moveBefore(), and llvm::User::operands().
◆ setLoopAlreadyUnrolled()
| void Loop::setLoopAlreadyUnrolled | ( | ) |
Add llvm.loop.unroll.disable to this loop's loop id metadata.
Remove existing unroll metadata and add unroll disable metadata to indicate the loop has already been unrolled. This prevents a loop from being unrolled more than is directed by a pragma if the loop unrolling pass is run more than once (which it generally is).
Definition at line 257 of file LoopInfo.cpp.
References Context, llvm::dyn_cast(), llvm::MDString::get(), llvm::MDNode::get(), llvm::BasicBlock::getContext(), llvm::LoopBase< BasicBlock, Loop >::getHeader(), getLoopID(), llvm::MDNode::getNumOperands(), llvm::MDNode::getOperand(), llvm::MDString::getString(), llvm::SmallVectorTemplateBase< T >::push_back(), llvm::MDNode::replaceOperandWith(), setLoopID(), and llvm::StringRef::startswith().
Referenced by CloneLoopBlocks(), tryToUnrollAndJamLoop(), and tryToUnrollLoop().
◆ setLoopID()
| void Loop::setLoopID | ( | MDNode * | LoopID | ) | const |
Set the llvm.loop loop id metadata for this loop.
The LoopID metadata node will be added to each terminator instruction in the loop that branches to the loop header.
The LoopID metadata node should have one or more operands and the first operand should be the node itself.
Definition at line 239 of file LoopInfo.cpp.
References assert(), llvm::LoopBase< BasicBlock, Loop >::blocks(), llvm::LoopBase< BasicBlock, Loop >::getHeader(), llvm::MDNode::getNumOperands(), llvm::MDNode::getOperand(), H, llvm::LLVMContext::MD_loop, llvm::Instruction::setMetadata(), llvm::Successor, and llvm::successors().
Referenced by AddRuntimeUnrollDisableMetaData(), CloneLoopBlocks(), llvm::InnerLoopVectorizer::createVectorizedLoopSkeleton(), DisableAllLoopOptsOnLoop(), llvm::LoopVectorizePass::processLoop(), setLoopAlreadyUnrolled(), tryToUnrollAndJamLoop(), and tryToUnrollLoop().
Friends And Related Function Documentation
◆ LoopBase< BasicBlock, Loop >
|
friend |
Definition at line 600 of file LoopInfo.h.
◆ LoopInfoBase< BasicBlock, Loop >
|
friend |
Definition at line 599 of file LoopInfo.h.
The documentation for this class was generated from the following files:
- include/llvm/Analysis/LoopInfo.h
- lib/Analysis/LoopInfo.cpp
