llvm-6502/include/llvm/Analysis/LoopInfo.h
Duncan P. N. Exon Smith f175439a2b Transforms: Use the new DebugLoc API, NFC
Update lib/Analysis and lib/Transforms to use the new `DebugLoc` API.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233587 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-30 19:49:49 +00:00

781 lines
28 KiB
C++

//===- llvm/Analysis/LoopInfo.h - Natural Loop Calculator -------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the LoopInfo class that is used to identify natural loops
// and determine the loop depth of various nodes of the CFG. A natural loop
// has exactly one entry-point, which is called the header. Note that natural
// loops may actually be several loops that share the same header node.
//
// This analysis calculates the nesting structure of loops in a function. For
// each natural loop identified, this analysis identifies natural loops
// contained entirely within the loop and the basic blocks the make up the loop.
//
// It can calculate on the fly various bits of information, for example:
//
// * whether there is a preheader for the loop
// * the number of back edges to the header
// * whether or not a particular block branches out of the loop
// * the successor blocks of the loop
// * the loop depth
// * etc...
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_LOOPINFO_H
#define LLVM_ANALYSIS_LOOPINFO_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Instruction.h"
#include "llvm/Pass.h"
#include <algorithm>
namespace llvm {
// FIXME: Replace this brittle forward declaration with the include of the new
// PassManager.h when doing so doesn't break the PassManagerBuilder.
template <typename IRUnitT> class AnalysisManager;
class PreservedAnalyses;
template<typename T>
inline void RemoveFromVector(std::vector<T*> &V, T *N) {
typename std::vector<T*>::iterator I = std::find(V.begin(), V.end(), N);
assert(I != V.end() && "N is not in this list!");
V.erase(I);
}
class DominatorTree;
class LoopInfo;
class Loop;
class MDNode;
class PHINode;
class raw_ostream;
template<class N> class DominatorTreeBase;
template<class N, class M> class LoopInfoBase;
template<class N, class M> class LoopBase;
//===----------------------------------------------------------------------===//
/// LoopBase class - Instances of this class are used to represent loops that
/// are detected in the flow graph
///
template<class BlockT, class LoopT>
class LoopBase {
LoopT *ParentLoop;
// SubLoops - Loops contained entirely within this one.
std::vector<LoopT *> SubLoops;
// Blocks - The list of blocks in this loop. First entry is the header node.
std::vector<BlockT*> Blocks;
SmallPtrSet<const BlockT*, 8> DenseBlockSet;
LoopBase(const LoopBase<BlockT, LoopT> &) = delete;
const LoopBase<BlockT, LoopT>&
operator=(const LoopBase<BlockT, LoopT> &) = delete;
public:
/// Loop ctor - This creates an empty loop.
LoopBase() : ParentLoop(nullptr) {}
~LoopBase() {
for (size_t i = 0, e = SubLoops.size(); i != e; ++i)
delete SubLoops[i];
}
/// getLoopDepth - Return the nesting level of this loop. An outer-most
/// loop has depth 1, for consistency with loop depth values used for basic
/// blocks, where depth 0 is used for blocks not inside any loops.
unsigned getLoopDepth() const {
unsigned D = 1;
for (const LoopT *CurLoop = ParentLoop; CurLoop;
CurLoop = CurLoop->ParentLoop)
++D;
return D;
}
BlockT *getHeader() const { return Blocks.front(); }
LoopT *getParentLoop() const { return ParentLoop; }
/// setParentLoop is a raw interface for bypassing addChildLoop.
void setParentLoop(LoopT *L) { ParentLoop = L; }
/// contains - Return true if the specified loop is contained within in
/// this loop.
///
bool contains(const LoopT *L) const {
if (L == this) return true;
if (!L) return false;
return contains(L->getParentLoop());
}
/// contains - Return true if the specified basic block is in this loop.
///
bool contains(const BlockT *BB) const {
return DenseBlockSet.count(BB);
}
/// contains - Return true if the specified instruction is in this loop.
///
template<class InstT>
bool contains(const InstT *Inst) const {
return contains(Inst->getParent());
}
/// iterator/begin/end - Return the loops contained entirely within this loop.
///
const std::vector<LoopT *> &getSubLoops() const { return SubLoops; }
std::vector<LoopT *> &getSubLoopsVector() { return SubLoops; }
typedef typename std::vector<LoopT *>::const_iterator iterator;
typedef typename std::vector<LoopT *>::const_reverse_iterator
reverse_iterator;
iterator begin() const { return SubLoops.begin(); }
iterator end() const { return SubLoops.end(); }
reverse_iterator rbegin() const { return SubLoops.rbegin(); }
reverse_iterator rend() const { return SubLoops.rend(); }
bool empty() const { return SubLoops.empty(); }
/// getBlocks - Get a list of the basic blocks which make up this loop.
///
const std::vector<BlockT*> &getBlocks() const { return Blocks; }
typedef typename std::vector<BlockT*>::const_iterator block_iterator;
block_iterator block_begin() const { return Blocks.begin(); }
block_iterator block_end() const { return Blocks.end(); }
/// getNumBlocks - Get the number of blocks in this loop in constant time.
unsigned getNumBlocks() const {
return Blocks.size();
}
/// isLoopExiting - True if terminator in the block can branch to another
/// block that is outside of the current loop.
///
bool isLoopExiting(const BlockT *BB) const {
typedef GraphTraits<const BlockT*> BlockTraits;
for (typename BlockTraits::ChildIteratorType SI =
BlockTraits::child_begin(BB),
SE = BlockTraits::child_end(BB); SI != SE; ++SI) {
if (!contains(*SI))
return true;
}
return false;
}
/// getNumBackEdges - Calculate the number of back edges to the loop header
///
unsigned getNumBackEdges() const {
unsigned NumBackEdges = 0;
BlockT *H = getHeader();
typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
for (typename InvBlockTraits::ChildIteratorType I =
InvBlockTraits::child_begin(H),
E = InvBlockTraits::child_end(H); I != E; ++I)
if (contains(*I))
++NumBackEdges;
return NumBackEdges;
}
//===--------------------------------------------------------------------===//
// APIs for simple analysis of the loop.
//
// Note that all of these methods can fail on general loops (ie, there may not
// be a preheader, etc). For best success, the loop simplification and
// induction variable canonicalization pass should be used to normalize loops
// for easy analysis. These methods assume canonical loops.
/// getExitingBlocks - Return all blocks inside the loop that have successors
/// outside of the loop. These are the blocks _inside of the current loop_
/// which branch out. The returned list is always unique.
///
void getExitingBlocks(SmallVectorImpl<BlockT *> &ExitingBlocks) const;
/// getExitingBlock - If getExitingBlocks would return exactly one block,
/// return that block. Otherwise return null.
BlockT *getExitingBlock() const;
/// getExitBlocks - Return all of the successor blocks of this loop. These
/// are the blocks _outside of the current loop_ which are branched to.
///
void getExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const;
/// getExitBlock - If getExitBlocks would return exactly one block,
/// return that block. Otherwise return null.
BlockT *getExitBlock() const;
/// Edge type.
typedef std::pair<const BlockT*, const BlockT*> Edge;
/// getExitEdges - Return all pairs of (_inside_block_,_outside_block_).
void getExitEdges(SmallVectorImpl<Edge> &ExitEdges) const;
/// getLoopPreheader - If there is a preheader for this loop, return it. A
/// loop has a preheader if there is only one edge to the header of the loop
/// from outside of the loop. If this is the case, the block branching to the
/// header of the loop is the preheader node.
///
/// This method returns null if there is no preheader for the loop.
///
BlockT *getLoopPreheader() const;
/// getLoopPredecessor - If the given loop's header has exactly one unique
/// predecessor outside the loop, return it. Otherwise return null.
/// This is less strict that the loop "preheader" concept, which requires
/// the predecessor to have exactly one successor.
///
BlockT *getLoopPredecessor() const;
/// getLoopLatch - If there is a single latch block for this loop, return it.
/// A latch block is a block that contains a branch back to the header.
BlockT *getLoopLatch() const;
/// getLoopLatches - Return all loop latch blocks of this loop. A latch block
/// is a block that contains a branch back to the header.
void getLoopLatches(SmallVectorImpl<BlockT *> &LoopLatches) const {
BlockT *H = getHeader();
typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
for (typename InvBlockTraits::ChildIteratorType I =
InvBlockTraits::child_begin(H),
E = InvBlockTraits::child_end(H); I != E; ++I)
if (contains(*I))
LoopLatches.push_back(*I);
}
//===--------------------------------------------------------------------===//
// APIs for updating loop information after changing the CFG
//
/// addBasicBlockToLoop - This method is used by other analyses to update loop
/// information. NewBB is set to be a new member of the current loop.
/// Because of this, it is added as a member of all parent loops, and is added
/// to the specified LoopInfo object as being in the current basic block. It
/// is not valid to replace the loop header with this method.
///
void addBasicBlockToLoop(BlockT *NewBB, LoopInfoBase<BlockT, LoopT> &LI);
/// replaceChildLoopWith - This is used when splitting loops up. It replaces
/// the OldChild entry in our children list with NewChild, and updates the
/// parent pointer of OldChild to be null and the NewChild to be this loop.
/// This updates the loop depth of the new child.
void replaceChildLoopWith(LoopT *OldChild, LoopT *NewChild);
/// addChildLoop - Add the specified loop to be a child of this loop. This
/// updates the loop depth of the new child.
///
void addChildLoop(LoopT *NewChild) {
assert(!NewChild->ParentLoop && "NewChild already has a parent!");
NewChild->ParentLoop = static_cast<LoopT *>(this);
SubLoops.push_back(NewChild);
}
/// removeChildLoop - This removes the specified child from being a subloop of
/// this loop. The loop is not deleted, as it will presumably be inserted
/// into another loop.
LoopT *removeChildLoop(iterator I) {
assert(I != SubLoops.end() && "Cannot remove end iterator!");
LoopT *Child = *I;
assert(Child->ParentLoop == this && "Child is not a child of this loop!");
SubLoops.erase(SubLoops.begin()+(I-begin()));
Child->ParentLoop = nullptr;
return Child;
}
/// addBlockEntry - This adds a basic block directly to the basic block list.
/// This should only be used by transformations that create new loops. Other
/// transformations should use addBasicBlockToLoop.
void addBlockEntry(BlockT *BB) {
Blocks.push_back(BB);
DenseBlockSet.insert(BB);
}
/// reverseBlocks - interface to reverse Blocks[from, end of loop] in this loop
void reverseBlock(unsigned from) {
std::reverse(Blocks.begin() + from, Blocks.end());
}
/// reserveBlocks- interface to do reserve() for Blocks
void reserveBlocks(unsigned size) {
Blocks.reserve(size);
}
/// moveToHeader - 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).
void moveToHeader(BlockT *BB) {
if (Blocks[0] == BB) return;
for (unsigned i = 0; ; ++i) {
assert(i != Blocks.size() && "Loop does not contain BB!");
if (Blocks[i] == BB) {
Blocks[i] = Blocks[0];
Blocks[0] = BB;
return;
}
}
}
/// removeBlockFromLoop - This removes the specified basic block from the
/// current loop, updating the Blocks as appropriate. This does not update
/// the mapping in the LoopInfo class.
void removeBlockFromLoop(BlockT *BB) {
RemoveFromVector(Blocks, BB);
DenseBlockSet.erase(BB);
}
/// verifyLoop - Verify loop structure
void verifyLoop() const;
/// verifyLoop - Verify loop structure of this loop and all nested loops.
void verifyLoopNest(DenseSet<const LoopT*> *Loops) const;
void print(raw_ostream &OS, unsigned Depth = 0) const;
protected:
friend class LoopInfoBase<BlockT, LoopT>;
explicit LoopBase(BlockT *BB) : ParentLoop(nullptr) {
Blocks.push_back(BB);
DenseBlockSet.insert(BB);
}
};
template<class BlockT, class LoopT>
raw_ostream& operator<<(raw_ostream &OS, const LoopBase<BlockT, LoopT> &Loop) {
Loop.print(OS);
return OS;
}
// Implementation in LoopInfoImpl.h
#ifdef __GNUC__
__extension__ extern template class LoopBase<BasicBlock, Loop>;
#endif
class Loop : public LoopBase<BasicBlock, Loop> {
public:
Loop() {}
/// isLoopInvariant - Return true if the specified value is loop invariant
///
bool isLoopInvariant(Value *V) const;
/// hasLoopInvariantOperands - Return true if all the operands of the
/// specified instruction are loop invariant.
bool hasLoopInvariantOperands(Instruction *I) 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.
///
bool makeLoopInvariant(Value *V, 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.
///
bool makeLoopInvariant(Instruction *I, bool &Changed,
Instruction *InsertPt = nullptr) 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.
///
PHINode *getCanonicalInductionVariable() const;
/// isLCSSAForm - Return true if the Loop is in LCSSA form
bool isLCSSAForm(DominatorTree &DT) const;
/// isLoopSimplifyForm - Return true if the Loop is in the form that
/// the LoopSimplify form transforms loops to, which is sometimes called
/// normal form.
bool isLoopSimplifyForm() const;
/// isSafeToClone - Return true if the loop body is safe to clone in practice.
bool isSafeToClone() 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.
bool isAnnotatedParallel() 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.
MDNode *getLoopID() 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 should be the node itself.
void setLoopID(MDNode *LoopID) const;
/// hasDedicatedExits - Return true if no exit block for the loop
/// has a predecessor that is outside the loop.
bool hasDedicatedExits() 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.
///
void getUniqueExitBlocks(SmallVectorImpl<BasicBlock *> &ExitBlocks) const;
/// getUniqueExitBlock - If getUniqueExitBlocks would return exactly one
/// block, return that block. Otherwise return null.
BasicBlock *getUniqueExitBlock() const;
void dump() const;
/// \brief 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.
DebugLoc getStartLoc() const {
BasicBlock *HeadBB;
// Try the pre-header first.
if ((HeadBB = getLoopPreheader()) != nullptr)
if (DebugLoc DL = HeadBB->getTerminator()->getDebugLoc())
return DL;
// If we have no pre-header or there are no instructions with debug
// info in it, try the header.
HeadBB = getHeader();
if (HeadBB)
return HeadBB->getTerminator()->getDebugLoc();
return DebugLoc();
}
private:
friend class LoopInfoBase<BasicBlock, Loop>;
explicit Loop(BasicBlock *BB) : LoopBase<BasicBlock, Loop>(BB) {}
};
//===----------------------------------------------------------------------===//
/// LoopInfo - This class builds and contains all of the top level loop
/// structures in the specified function.
///
template<class BlockT, class LoopT>
class LoopInfoBase {
// BBMap - Mapping of basic blocks to the inner most loop they occur in
DenseMap<BlockT *, LoopT *> BBMap;
std::vector<LoopT *> TopLevelLoops;
friend class LoopBase<BlockT, LoopT>;
friend class LoopInfo;
void operator=(const LoopInfoBase &) = delete;
LoopInfoBase(const LoopInfoBase &) = delete;
public:
LoopInfoBase() { }
~LoopInfoBase() { releaseMemory(); }
LoopInfoBase(LoopInfoBase &&Arg)
: BBMap(std::move(Arg.BBMap)),
TopLevelLoops(std::move(Arg.TopLevelLoops)) {
// We have to clear the arguments top level loops as we've taken ownership.
Arg.TopLevelLoops.clear();
}
LoopInfoBase &operator=(LoopInfoBase &&RHS) {
BBMap = std::move(RHS.BBMap);
for (auto *L : TopLevelLoops)
delete L;
TopLevelLoops = std::move(RHS.TopLevelLoops);
RHS.TopLevelLoops.clear();
return *this;
}
void releaseMemory() {
BBMap.clear();
for (auto *L : TopLevelLoops)
delete L;
TopLevelLoops.clear();
}
/// iterator/begin/end - The interface to the top-level loops in the current
/// function.
///
typedef typename std::vector<LoopT *>::const_iterator iterator;
typedef typename std::vector<LoopT *>::const_reverse_iterator
reverse_iterator;
iterator begin() const { return TopLevelLoops.begin(); }
iterator end() const { return TopLevelLoops.end(); }
reverse_iterator rbegin() const { return TopLevelLoops.rbegin(); }
reverse_iterator rend() const { return TopLevelLoops.rend(); }
bool empty() const { return TopLevelLoops.empty(); }
/// getLoopFor - Return the inner most loop that BB lives in. If a basic
/// block is in no loop (for example the entry node), null is returned.
///
LoopT *getLoopFor(const BlockT *BB) const {
return BBMap.lookup(const_cast<BlockT*>(BB));
}
/// operator[] - same as getLoopFor...
///
const LoopT *operator[](const BlockT *BB) const {
return getLoopFor(BB);
}
/// getLoopDepth - Return the loop nesting level of the specified block. A
/// depth of 0 means the block is not inside any loop.
///
unsigned getLoopDepth(const BlockT *BB) const {
const LoopT *L = getLoopFor(BB);
return L ? L->getLoopDepth() : 0;
}
// isLoopHeader - True if the block is a loop header node
bool isLoopHeader(BlockT *BB) const {
const LoopT *L = getLoopFor(BB);
return L && L->getHeader() == BB;
}
/// removeLoop - This removes the specified top-level loop from this loop info
/// object. The loop is not deleted, as it will presumably be inserted into
/// another loop.
LoopT *removeLoop(iterator I) {
assert(I != end() && "Cannot remove end iterator!");
LoopT *L = *I;
assert(!L->getParentLoop() && "Not a top-level loop!");
TopLevelLoops.erase(TopLevelLoops.begin() + (I-begin()));
return L;
}
/// changeLoopFor - Change the top-level loop that contains BB to the
/// specified loop. This should be used by transformations that restructure
/// the loop hierarchy tree.
void changeLoopFor(BlockT *BB, LoopT *L) {
if (!L) {
BBMap.erase(BB);
return;
}
BBMap[BB] = L;
}
/// changeTopLevelLoop - Replace the specified loop in the top-level loops
/// list with the indicated loop.
void changeTopLevelLoop(LoopT *OldLoop,
LoopT *NewLoop) {
auto I = std::find(TopLevelLoops.begin(), TopLevelLoops.end(), OldLoop);
assert(I != TopLevelLoops.end() && "Old loop not at top level!");
*I = NewLoop;
assert(!NewLoop->ParentLoop && !OldLoop->ParentLoop &&
"Loops already embedded into a subloop!");
}
/// addTopLevelLoop - This adds the specified loop to the collection of
/// top-level loops.
void addTopLevelLoop(LoopT *New) {
assert(!New->getParentLoop() && "Loop already in subloop!");
TopLevelLoops.push_back(New);
}
/// removeBlock - This method completely removes BB from all data structures,
/// including all of the Loop objects it is nested in and our mapping from
/// BasicBlocks to loops.
void removeBlock(BlockT *BB) {
auto I = BBMap.find(BB);
if (I != BBMap.end()) {
for (LoopT *L = I->second; L; L = L->getParentLoop())
L->removeBlockFromLoop(BB);
BBMap.erase(I);
}
}
// Internals
static bool isNotAlreadyContainedIn(const LoopT *SubLoop,
const LoopT *ParentLoop) {
if (!SubLoop) return true;
if (SubLoop == ParentLoop) return false;
return isNotAlreadyContainedIn(SubLoop->getParentLoop(), ParentLoop);
}
/// Create the loop forest using a stable algorithm.
void Analyze(DominatorTreeBase<BlockT> &DomTree);
// Debugging
void print(raw_ostream &OS) const;
void verify() const;
};
// Implementation in LoopInfoImpl.h
#ifdef __GNUC__
__extension__ extern template class LoopInfoBase<BasicBlock, Loop>;
#endif
class LoopInfo : public LoopInfoBase<BasicBlock, Loop> {
typedef LoopInfoBase<BasicBlock, Loop> BaseT;
friend class LoopBase<BasicBlock, Loop>;
void operator=(const LoopInfo &) = delete;
LoopInfo(const LoopInfo &) = delete;
public:
LoopInfo() {}
LoopInfo(LoopInfo &&Arg) : BaseT(std::move(static_cast<BaseT &>(Arg))) {}
LoopInfo &operator=(LoopInfo &&RHS) {
BaseT::operator=(std::move(static_cast<BaseT &>(RHS)));
return *this;
}
// Most of the public interface is provided via LoopInfoBase.
/// updateUnloop - Update LoopInfo after removing the last backedge from a
/// loop--now the "unloop". This updates the loop forest and parent loops for
/// each block so that Unloop is no longer referenced, but the caller must
/// actually delete the Unloop object.
void updateUnloop(Loop *Unloop);
/// replacementPreservesLCSSAForm - Returns true if replacing From with To
/// everywhere is guaranteed to preserve LCSSA form.
bool replacementPreservesLCSSAForm(Instruction *From, Value *To) {
// Preserving LCSSA form is only problematic if the replacing value is an
// instruction.
Instruction *I = dyn_cast<Instruction>(To);
if (!I) return true;
// If both instructions are defined in the same basic block then replacement
// cannot break LCSSA form.
if (I->getParent() == From->getParent())
return true;
// If the instruction is not defined in a loop then it can safely replace
// anything.
Loop *ToLoop = getLoopFor(I->getParent());
if (!ToLoop) return true;
// If the replacing instruction is defined in the same loop as the original
// instruction, or in a loop that contains it as an inner loop, then using
// it as a replacement will not break LCSSA form.
return ToLoop->contains(getLoopFor(From->getParent()));
}
};
// Allow clients to walk the list of nested loops...
template <> struct GraphTraits<const Loop*> {
typedef const Loop NodeType;
typedef LoopInfo::iterator ChildIteratorType;
static NodeType *getEntryNode(const Loop *L) { return L; }
static inline ChildIteratorType child_begin(NodeType *N) {
return N->begin();
}
static inline ChildIteratorType child_end(NodeType *N) {
return N->end();
}
};
template <> struct GraphTraits<Loop*> {
typedef Loop NodeType;
typedef LoopInfo::iterator ChildIteratorType;
static NodeType *getEntryNode(Loop *L) { return L; }
static inline ChildIteratorType child_begin(NodeType *N) {
return N->begin();
}
static inline ChildIteratorType child_end(NodeType *N) {
return N->end();
}
};
/// \brief Analysis pass that exposes the \c LoopInfo for a function.
class LoopAnalysis {
static char PassID;
public:
typedef LoopInfo Result;
/// \brief Opaque, unique identifier for this analysis pass.
static void *ID() { return (void *)&PassID; }
/// \brief Provide a name for the analysis for debugging and logging.
static StringRef name() { return "LoopAnalysis"; }
LoopAnalysis() {}
LoopAnalysis(const LoopAnalysis &Arg) {}
LoopAnalysis(LoopAnalysis &&Arg) {}
LoopAnalysis &operator=(const LoopAnalysis &RHS) { return *this; }
LoopAnalysis &operator=(LoopAnalysis &&RHS) { return *this; }
LoopInfo run(Function &F, AnalysisManager<Function> *AM);
};
/// \brief Printer pass for the \c LoopAnalysis results.
class LoopPrinterPass {
raw_ostream &OS;
public:
explicit LoopPrinterPass(raw_ostream &OS) : OS(OS) {}
PreservedAnalyses run(Function &F, AnalysisManager<Function> *AM);
static StringRef name() { return "LoopPrinterPass"; }
};
/// \brief The legacy pass manager's analysis pass to compute loop information.
class LoopInfoWrapperPass : public FunctionPass {
LoopInfo LI;
public:
static char ID; // Pass identification, replacement for typeid
LoopInfoWrapperPass() : FunctionPass(ID) {
initializeLoopInfoWrapperPassPass(*PassRegistry::getPassRegistry());
}
LoopInfo &getLoopInfo() { return LI; }
const LoopInfo &getLoopInfo() const { return LI; }
/// \brief Calculate the natural loop information for a given function.
bool runOnFunction(Function &F) override;
void verifyAnalysis() const override;
void releaseMemory() override { LI.releaseMemory(); }
void print(raw_ostream &O, const Module *M = nullptr) const override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
};
} // End llvm namespace
#endif