#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/Analysis/Dominators.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
#include "llvm/Pass.h"
#include <algorithm>
namespace llvm {
-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);
-}
+// 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;
class DominatorTree;
class LoopInfo;
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;
// Blocks - The list of blocks in this loop. First entry is the header node.
std::vector<BlockT*> Blocks;
- LoopBase(const LoopBase<BlockT, LoopT> &) LLVM_DELETED_FUNCTION;
+ SmallPtrSet<const BlockT*, 8> DenseBlockSet;
+
+ /// Indicator that this loop is no longer a valid loop.
+ bool IsInvalid = false;
+
+ LoopBase(const LoopBase<BlockT, LoopT> &) = delete;
const LoopBase<BlockT, LoopT>&
- operator=(const LoopBase<BlockT, LoopT> &) LLVM_DELETED_FUNCTION;
+ operator=(const LoopBase<BlockT, LoopT> &) = delete;
public:
/// Loop ctor - This creates an empty loop.
- LoopBase() : ParentLoop(0) {}
+ LoopBase() : ParentLoop(nullptr) {}
~LoopBase() {
for (size_t i = 0, e = SubLoops.size(); i != e; ++i)
delete SubLoops[i];
///
bool contains(const LoopT *L) const {
if (L == this) return true;
- if (L == 0) return false;
+ 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 std::find(block_begin(), block_end(), BB) != block_end();
+ return DenseBlockSet.count(BB);
}
/// contains - Return true if the specified instruction is in this loop.
/// getBlocks - Get a list of the basic blocks which make up this loop.
///
const std::vector<BlockT*> &getBlocks() const { return Blocks; }
- std::vector<BlockT*> &getBlocksVector() { 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(); }
+ inline iterator_range<block_iterator> blocks() const {
+ return make_range(block_begin(), block_end());
+ }
/// getNumBlocks - Get the number of blocks in this loop in constant time.
unsigned getNumBlocks() const {
return Blocks.size();
}
+ /// Invalidate the loop, indicating that it is no longer a loop.
+ void invalidate() { IsInvalid = true; }
+
+ /// Return true if this loop is no longer valid.
+ bool isInvalid() { return IsInvalid; }
+
/// isLoopExiting - True if terminator in the block can branch to another
/// block that is outside of the current loop.
///
/// 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
//
/// updates the loop depth of the new child.
///
void addChildLoop(LoopT *NewChild) {
- assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!");
+ assert(!NewChild->ParentLoop && "NewChild already has a parent!");
NewChild->ParentLoop = static_cast<LoopT *>(this);
SubLoops.push_back(NewChild);
}
LoopT *Child = *I;
assert(Child->ParentLoop == this && "Child is not a child of this loop!");
SubLoops.erase(SubLoops.begin()+(I-begin()));
- Child->ParentLoop = 0;
+ Child->ParentLoop = nullptr;
return Child;
}
/// 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
/// current loop, updating the Blocks as appropriate. This does not update
/// the mapping in the LoopInfo class.
void removeBlockFromLoop(BlockT *BB) {
- RemoveFromVector(Blocks, BB);
+ auto I = std::find(Blocks.begin(), Blocks.end(), BB);
+ assert(I != Blocks.end() && "N is not in this list!");
+ Blocks.erase(I);
+
+ DenseBlockSet.erase(BB);
}
/// verifyLoop - Verify loop structure
protected:
friend class LoopInfoBase<BlockT, LoopT>;
- explicit LoopBase(BlockT *BB) : ParentLoop(0) {
+ explicit LoopBase(BlockT *BB) : ParentLoop(nullptr) {
Blocks.push_back(BB);
+ DenseBlockSet.insert(BB);
}
};
}
// Implementation in LoopInfoImpl.h
-#ifdef __GNUC__
-__extension__ extern template class LoopBase<BasicBlock, Loop>;
-#endif
+extern template class LoopBase<BasicBlock, Loop>;
class Loop : public LoopBase<BasicBlock, Loop> {
public:
/// isLoopInvariant - Return true if the specified value is loop invariant
///
- bool isLoopInvariant(Value *V) const;
+ bool isLoopInvariant(const Value *V) const;
/// hasLoopInvariantOperands - Return true if all the operands of the
/// specified instruction are loop invariant.
- bool hasLoopInvariantOperands(Instruction *I) const;
+ bool hasLoopInvariantOperands(const 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.
/// If null, the terminator of the loop preheader is used.
///
bool makeLoopInvariant(Value *V, bool &Changed,
- Instruction *InsertPt = 0) const;
+ 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.
/// If null, the terminator of the loop preheader is used.
///
bool makeLoopInvariant(Instruction *I, bool &Changed,
- Instruction *InsertPt = 0) const;
+ 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
/// isLCSSAForm - Return true if the Loop is in LCSSA form
bool isLCSSAForm(DominatorTree &DT) const;
+ /// \brief Return true if this Loop and all inner subloops are in LCSSA form.
+ bool isRecursivelyLCSSAForm(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.
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) {}
template<class BlockT, class LoopT>
class LoopInfoBase {
// BBMap - Mapping of basic blocks to the inner most loop they occur in
- DenseMap<BlockT *, LoopT *> BBMap;
+ DenseMap<const BlockT *, LoopT *> BBMap;
std::vector<LoopT *> TopLevelLoops;
+ std::vector<LoopT *> RemovedLoops;
+
friend class LoopBase<BlockT, LoopT>;
friend class LoopInfo;
- void operator=(const LoopInfoBase &) LLVM_DELETED_FUNCTION;
- LoopInfoBase(const LoopInfo &) LLVM_DELETED_FUNCTION;
+ 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() {
- for (typename std::vector<LoopT *>::iterator I =
- TopLevelLoops.begin(), E = TopLevelLoops.end(); I != E; ++I)
- delete *I; // Delete all of the loops...
+ BBMap.clear();
- BBMap.clear(); // Reset internal state of analysis
+ for (auto *L : TopLevelLoops)
+ delete L;
TopLevelLoops.clear();
+ for (auto *L : RemovedLoops)
+ delete L;
+ RemovedLoops.clear();
}
/// iterator/begin/end - The interface to the top-level loops in the current
/// 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));
- }
+ LoopT *getLoopFor(const BlockT *BB) const { return BBMap.lookup(BB); }
/// operator[] - same as getLoopFor...
///
}
// isLoopHeader - True if the block is a loop header node
- bool isLoopHeader(BlockT *BB) const {
+ bool isLoopHeader(const BlockT *BB) const {
const LoopT *L = getLoopFor(BB);
return L && L->getHeader() == BB;
}
LoopT *removeLoop(iterator I) {
assert(I != end() && "Cannot remove end iterator!");
LoopT *L = *I;
- assert(L->getParentLoop() == 0 && "Not a top-level loop!");
+ assert(!L->getParentLoop() && "Not a top-level loop!");
TopLevelLoops.erase(TopLevelLoops.begin() + (I-begin()));
return L;
}
/// list with the indicated loop.
void changeTopLevelLoop(LoopT *OldLoop,
LoopT *NewLoop) {
- typename std::vector<LoopT *>::iterator I =
- std::find(TopLevelLoops.begin(), TopLevelLoops.end(), OldLoop);
+ auto I = std::find(TopLevelLoops.begin(), TopLevelLoops.end(), OldLoop);
assert(I != TopLevelLoops.end() && "Old loop not at top level!");
*I = NewLoop;
- assert(NewLoop->ParentLoop == 0 && OldLoop->ParentLoop == 0 &&
+ 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() == 0 && "Loop already in subloop!");
+ assert(!New->getParentLoop() && "Loop already in subloop!");
TopLevelLoops.push_back(New);
}
/// including all of the Loop objects it is nested in and our mapping from
/// BasicBlocks to loops.
void removeBlock(BlockT *BB) {
- typename DenseMap<BlockT *, LoopT *>::iterator I = BBMap.find(BB);
+ auto I = BBMap.find(BB);
if (I != BBMap.end()) {
for (LoopT *L = I->second; L; L = L->getParentLoop())
L->removeBlockFromLoop(BB);
static bool isNotAlreadyContainedIn(const LoopT *SubLoop,
const LoopT *ParentLoop) {
- if (SubLoop == 0) return true;
+ 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);
+ void analyze(const 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
+extern template class LoopInfoBase<BasicBlock, Loop>;
+
+class LoopInfo : public LoopInfoBase<BasicBlock, Loop> {
+ typedef LoopInfoBase<BasicBlock, Loop> BaseT;
-class LoopInfo : public FunctionPass {
- LoopInfoBase<BasicBlock, Loop> LI;
friend class LoopBase<BasicBlock, Loop>;
- void operator=(const LoopInfo &) LLVM_DELETED_FUNCTION;
- LoopInfo(const LoopInfo &) LLVM_DELETED_FUNCTION;
+ void operator=(const LoopInfo &) = delete;
+ LoopInfo(const LoopInfo &) = delete;
public:
- static char ID; // Pass identification, replacement for typeid
-
- LoopInfo() : FunctionPass(ID) {
- initializeLoopInfoPass(*PassRegistry::getPassRegistry());
- }
-
- LoopInfoBase<BasicBlock, Loop>& getBase() { return LI; }
-
- /// iterator/begin/end - The interface to the top-level loops in the current
- /// function.
- ///
- typedef LoopInfoBase<BasicBlock, Loop>::iterator iterator;
- typedef LoopInfoBase<BasicBlock, Loop>::reverse_iterator reverse_iterator;
- inline iterator begin() const { return LI.begin(); }
- inline iterator end() const { return LI.end(); }
- inline reverse_iterator rbegin() const { return LI.rbegin(); }
- inline reverse_iterator rend() const { return LI.rend(); }
- bool empty() const { return LI.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.
- ///
- inline Loop *getLoopFor(const BasicBlock *BB) const {
- return LI.getLoopFor(BB);
- }
-
- /// operator[] - same as getLoopFor...
- ///
- inline const Loop *operator[](const BasicBlock *BB) const {
- return LI.getLoopFor(BB);
- }
+ LoopInfo() {}
+ explicit LoopInfo(const DominatorTreeBase<BasicBlock> &DomTree);
- /// getLoopDepth - Return the loop nesting level of the specified block. A
- /// depth of 0 means the block is not inside any loop.
- ///
- inline unsigned getLoopDepth(const BasicBlock *BB) const {
- return LI.getLoopDepth(BB);
+ LoopInfo(LoopInfo &&Arg) : BaseT(std::move(static_cast<BaseT &>(Arg))) {}
+ LoopInfo &operator=(LoopInfo &&RHS) {
+ BaseT::operator=(std::move(static_cast<BaseT &>(RHS)));
+ return *this;
}
- // isLoopHeader - True if the block is a loop header node
- inline bool isLoopHeader(BasicBlock *BB) const {
- return LI.isLoopHeader(BB);
- }
-
- /// runOnFunction - Calculate the natural loop information.
- ///
- virtual bool runOnFunction(Function &F);
-
- virtual void verifyAnalysis() const;
+ // Most of the public interface is provided via LoopInfoBase.
- virtual void releaseMemory() { LI.releaseMemory(); }
-
- virtual void print(raw_ostream &O, const Module* M = 0) const;
-
- virtual void getAnalysisUsage(AnalysisUsage &AU) const;
-
- /// 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.
- inline Loop *removeLoop(iterator I) { return LI.removeLoop(I); }
-
- /// 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.
- inline void changeLoopFor(BasicBlock *BB, Loop *L) {
- LI.changeLoopFor(BB, L);
- }
-
- /// changeTopLevelLoop - Replace the specified loop in the top-level loops
- /// list with the indicated loop.
- inline void changeTopLevelLoop(Loop *OldLoop, Loop *NewLoop) {
- LI.changeTopLevelLoop(OldLoop, NewLoop);
- }
-
- /// addTopLevelLoop - This adds the specified loop to the collection of
- /// top-level loops.
- inline void addTopLevelLoop(Loop *New) {
- LI.addTopLevelLoop(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(BasicBlock *BB) {
- LI.removeBlock(BB);
- }
-
- /// 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);
+ /// Update LoopInfo after removing the last backedge from a loop. This updates
+ /// the loop forest and parent loops for each block so that \c L is no longer
+ /// referenced, but does not actually delete \c L immediately. The pointer
+ /// will remain valid until this LoopInfo's memory is released.
+ void markAsRemoved(Loop *L);
/// replacementPreservesLCSSAForm - Returns true if replacing From with To
/// everywhere is guaranteed to preserve LCSSA form.
// it as a replacement will not break LCSSA form.
return ToLoop->contains(getLoopFor(From->getParent()));
}
-};
+ /// \brief Checks if moving a specific instruction can break LCSSA in any
+ /// loop.
+ ///
+ /// Return true if moving \p Inst to before \p NewLoc will break LCSSA,
+ /// assuming that the function containing \p Inst and \p NewLoc is currently
+ /// in LCSSA form.
+ bool movementPreservesLCSSAForm(Instruction *Inst, Instruction *NewLoc) {
+ assert(Inst->getFunction() == NewLoc->getFunction() &&
+ "Can't reason about IPO!");
+
+ auto *OldBB = Inst->getParent();
+ auto *NewBB = NewLoc->getParent();
+
+ // Movement within the same loop does not break LCSSA (the equality check is
+ // to avoid doing a hashtable lookup in case of intra-block movement).
+ if (OldBB == NewBB)
+ return true;
+
+ auto *OldLoop = getLoopFor(OldBB);
+ auto *NewLoop = getLoopFor(NewBB);
+
+ if (OldLoop == NewLoop)
+ return true;
+
+ // Check if Outer contains Inner; with the null loop counting as the
+ // "outermost" loop.
+ auto Contains = [](const Loop *Outer, const Loop *Inner) {
+ return !Outer || Outer->contains(Inner);
+ };
+
+ // To check that the movement of Inst to before NewLoc does not break LCSSA,
+ // we need to check two sets of uses for possible LCSSA violations at
+ // NewLoc: the users of NewInst, and the operands of NewInst.
+
+ // If we know we're hoisting Inst out of an inner loop to an outer loop,
+ // then the uses *of* Inst don't need to be checked.
+
+ if (!Contains(NewLoop, OldLoop)) {
+ for (Use &U : Inst->uses()) {
+ auto *UI = cast<Instruction>(U.getUser());
+ auto *UBB = isa<PHINode>(UI) ? cast<PHINode>(UI)->getIncomingBlock(U)
+ : UI->getParent();
+ if (UBB != NewBB && getLoopFor(UBB) != NewLoop)
+ return false;
+ }
+ }
+
+ // If we know we're sinking Inst from an outer loop into an inner loop, then
+ // the *operands* of Inst don't need to be checked.
+
+ if (!Contains(OldLoop, NewLoop)) {
+ // See below on why we can't handle phi nodes here.
+ if (isa<PHINode>(Inst))
+ return false;
+
+ for (Use &U : Inst->operands()) {
+ auto *DefI = dyn_cast<Instruction>(U.get());
+ if (!DefI)
+ return false;
+
+ // This would need adjustment if we allow Inst to be a phi node -- the
+ // new use block won't simply be NewBB.
+
+ auto *DefBlock = DefI->getParent();
+ if (DefBlock != NewBB && getLoopFor(DefBlock) != NewLoop)
+ return false;
+ }
+ }
+
+ return true;
+ }
+};
// Allow clients to walk the list of nested loops...
template <> struct GraphTraits<const Loop*> {
}
};
+/// \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"; }
+
+ 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;
+};
+
+/// \brief Pass for printing a loop's contents as LLVM's text IR assembly.
+class PrintLoopPass {
+ raw_ostream &OS;
+ std::string Banner;
+
+public:
+ PrintLoopPass();
+ PrintLoopPass(raw_ostream &OS, const std::string &Banner = "");
+
+ PreservedAnalyses run(Loop &L);
+ static StringRef name() { return "PrintLoopPass"; }
+};
+
} // End llvm namespace
#endif
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