diff options
Diffstat (limited to 'include/llvm/Analysis/LoopInfo.h')
| -rw-r--r-- | include/llvm/Analysis/LoopInfo.h | 632 |
1 files changed, 286 insertions, 346 deletions
diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h index 8b293cb..7631110 100644 --- a/include/llvm/Analysis/LoopInfo.h +++ b/include/llvm/Analysis/LoopInfo.h @@ -8,7 +8,8 @@ //===----------------------------------------------------------------------===// // // This file defines the LoopInfo class that is used to identify natural loops -// and determine the loop depth of various nodes of the CFG. Note that natural +// 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 @@ -31,17 +32,13 @@ #define LLVM_ANALYSIS_LOOP_INFO_H #include "llvm/Pass.h" -#include "llvm/Constants.h" -#include "llvm/Instructions.h" #include "llvm/ADT/DepthFirstIterator.h" #include "llvm/ADT/GraphTraits.h" -#include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/SmallVector.h" #include "llvm/Analysis/Dominators.h" #include "llvm/Support/CFG.h" -#include "llvm/Support/Streams.h" +#include "llvm/Support/raw_ostream.h" #include <algorithm> -#include <ostream> namespace llvm { @@ -54,26 +51,27 @@ static void RemoveFromVector(std::vector<T*> &V, T *N) { class DominatorTree; class LoopInfo; -template<class N> class LoopInfoBase; -template<class N> class LoopBase; - -typedef LoopBase<BasicBlock> Loop; +class Loop; +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> +template<class BlockT, class LoopT> class LoopBase { - LoopBase<BlockT> *ParentLoop; + LoopT *ParentLoop; // SubLoops - Loops contained entirely within this one. - std::vector<LoopBase<BlockT>*> SubLoops; + std::vector<LoopT *> SubLoops; // Blocks - The list of blocks in this loop. First entry is the header node. std::vector<BlockT*> Blocks; - LoopBase(const LoopBase<BlockT> &); // DO NOT IMPLEMENT - const LoopBase<BlockT>&operator=(const LoopBase<BlockT> &);// DO NOT IMPLEMENT + // DO NOT IMPLEMENT + LoopBase(const LoopBase<BlockT, LoopT> &); + // DO NOT IMPLEMENT + const LoopBase<BlockT, LoopT>&operator=(const LoopBase<BlockT, LoopT> &); public: /// Loop ctor - This creates an empty loop. LoopBase() : ParentLoop(0) {} @@ -87,13 +85,13 @@ public: /// blocks, where depth 0 is used for blocks not inside any loops. unsigned getLoopDepth() const { unsigned D = 1; - for (const LoopBase<BlockT> *CurLoop = ParentLoop; CurLoop; + for (const LoopT *CurLoop = ParentLoop; CurLoop; CurLoop = CurLoop->ParentLoop) ++D; return D; } BlockT *getHeader() const { return Blocks.front(); } - LoopBase<BlockT> *getParentLoop() const { return ParentLoop; } + LoopT *getParentLoop() const { return ParentLoop; } /// contains - Return true if the specified basic block is in this loop /// @@ -103,8 +101,8 @@ public: /// iterator/begin/end - Return the loops contained entirely within this loop. /// - const std::vector<LoopBase<BlockT>*> &getSubLoops() const { return SubLoops; } - typedef typename std::vector<LoopBase<BlockT>*>::const_iterator iterator; + const std::vector<LoopT *> &getSubLoops() const { return SubLoops; } + typedef typename std::vector<LoopT *>::const_iterator iterator; iterator begin() const { return SubLoops.begin(); } iterator end() const { return SubLoops.end(); } bool empty() const { return SubLoops.empty(); } @@ -146,14 +144,6 @@ public: return NumBackEdges; } - /// isLoopInvariant - Return true if the specified value is loop invariant - /// - inline bool isLoopInvariant(Value *V) const { - if (Instruction *I = dyn_cast<Instruction>(V)) - return !contains(I->getParent()); - return true; // All non-instructions are loop invariant - } - //===--------------------------------------------------------------------===// // APIs for simple analysis of the loop. // @@ -223,72 +213,22 @@ public: return 0; } - /// 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 is in canonical form. - /// - void getUniqueExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const { + /// getExitEdges - Return all pairs of (_inside_block_,_outside_block_). + typedef std::pair<const BlockT*,const BlockT*> Edge; + void getExitEdges(SmallVectorImpl<Edge> &ExitEdges) const { // Sort the blocks vector so that we can use binary search to do quick // lookups. SmallVector<BlockT*, 128> LoopBBs(block_begin(), block_end()); std::sort(LoopBBs.begin(), LoopBBs.end()); - std::vector<BlockT*> switchExitBlocks; - - for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI) { - - BlockT *current = *BI; - switchExitBlocks.clear(); - - typedef GraphTraits<BlockT*> BlockTraits; - typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits; + typedef GraphTraits<BlockT*> BlockTraits; + for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI) for (typename BlockTraits::ChildIteratorType I = BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI); - I != E; ++I) { - if (std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I)) - // If block is inside the loop then it is not a exit block. - continue; - - typename InvBlockTraits::ChildIteratorType PI = - InvBlockTraits::child_begin(*I); - BlockT *firstPred = *PI; - - // If current basic block is this exit block's first predecessor - // then only insert exit block in to the output ExitBlocks vector. - // This ensures that same exit block is not inserted twice into - // ExitBlocks vector. - if (current != firstPred) - continue; - - // If a terminator has more then two successors, for example SwitchInst, - // then it is possible that there are multiple edges from current block - // to one exit block. - if (std::distance(BlockTraits::child_begin(current), - BlockTraits::child_end(current)) <= 2) { - ExitBlocks.push_back(*I); - continue; - } - - // In case of multiple edges from current block to exit block, collect - // only one edge in ExitBlocks. Use switchExitBlocks to keep track of - // duplicate edges. - if (std::find(switchExitBlocks.begin(), switchExitBlocks.end(), *I) - == switchExitBlocks.end()) { - switchExitBlocks.push_back(*I); - ExitBlocks.push_back(*I); - } - } - } - } - - /// getUniqueExitBlock - If getUniqueExitBlocks would return exactly one - /// block, return that block. Otherwise return null. - BlockT *getUniqueExitBlock() const { - SmallVector<BlockT*, 8> UniqueExitBlocks; - getUniqueExitBlocks(UniqueExitBlocks); - if (UniqueExitBlocks.size() == 1) - return UniqueExitBlocks[0]; - return 0; + I != E; ++I) + if (!std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I)) + // Not in current loop? It must be an exit block. + ExitEdges.push_back(std::make_pair(*BI, *I)); } /// getLoopPreheader - If there is a preheader for this loop, return it. A @@ -355,178 +295,6 @@ public: return Latch; } - - /// 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. - /// - inline PHINode *getCanonicalInductionVariable() const { - BlockT *H = getHeader(); - - BlockT *Incoming = 0, *Backedge = 0; - typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits; - typename InvBlockTraits::ChildIteratorType PI = - InvBlockTraits::child_begin(H); - assert(PI != InvBlockTraits::child_end(H) && - "Loop must have at least one backedge!"); - Backedge = *PI++; - if (PI == InvBlockTraits::child_end(H)) return 0; // dead loop - Incoming = *PI++; - if (PI != InvBlockTraits::child_end(H)) return 0; // multiple backedges? - - if (contains(Incoming)) { - if (contains(Backedge)) - return 0; - std::swap(Incoming, Backedge); - } else if (!contains(Backedge)) - return 0; - - // Loop over all of the PHI nodes, looking for a canonical indvar. - for (typename BlockT::iterator I = H->begin(); isa<PHINode>(I); ++I) { - PHINode *PN = cast<PHINode>(I); - if (ConstantInt *CI = - dyn_cast<ConstantInt>(PN->getIncomingValueForBlock(Incoming))) - if (CI->isNullValue()) - if (Instruction *Inc = - dyn_cast<Instruction>(PN->getIncomingValueForBlock(Backedge))) - if (Inc->getOpcode() == Instruction::Add && - Inc->getOperand(0) == PN) - if (ConstantInt *CI = dyn_cast<ConstantInt>(Inc->getOperand(1))) - if (CI->equalsInt(1)) - return PN; - } - return 0; - } - - /// getCanonicalInductionVariableIncrement - Return the LLVM value that holds - /// the canonical induction variable value for the "next" iteration of the - /// loop. This always succeeds if getCanonicalInductionVariable succeeds. - /// - inline Instruction *getCanonicalInductionVariableIncrement() const { - if (PHINode *PN = getCanonicalInductionVariable()) { - bool P1InLoop = contains(PN->getIncomingBlock(1)); - return cast<Instruction>(PN->getIncomingValue(P1InLoop)); - } - return 0; - } - - /// getTripCount - Return a loop-invariant LLVM value indicating the number of - /// times the loop will be executed. Note that this means that the backedge - /// of the loop executes N-1 times. If the trip-count cannot be determined, - /// this returns null. - /// - /// The IndVarSimplify pass transforms loops to have a form that this - /// function easily understands. - /// - inline Value *getTripCount() const { - // Canonical loops will end with a 'cmp ne I, V', where I is the incremented - // canonical induction variable and V is the trip count of the loop. - Instruction *Inc = getCanonicalInductionVariableIncrement(); - if (Inc == 0) return 0; - PHINode *IV = cast<PHINode>(Inc->getOperand(0)); - - BlockT *BackedgeBlock = - IV->getIncomingBlock(contains(IV->getIncomingBlock(1))); - - if (BranchInst *BI = dyn_cast<BranchInst>(BackedgeBlock->getTerminator())) - if (BI->isConditional()) { - if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition())) { - if (ICI->getOperand(0) == Inc) { - if (BI->getSuccessor(0) == getHeader()) { - if (ICI->getPredicate() == ICmpInst::ICMP_NE) - return ICI->getOperand(1); - } else if (ICI->getPredicate() == ICmpInst::ICMP_EQ) { - return ICI->getOperand(1); - } - } - } - } - - return 0; - } - - /// getSmallConstantTripCount - Returns the trip count of this loop as a - /// normal unsigned value, if possible. Returns 0 if the trip count is unknown - /// of not constant. Will also return 0 if the trip count is very large - /// (>= 2^32) - inline unsigned getSmallConstantTripCount() const { - Value* TripCount = this->getTripCount(); - if (TripCount) { - if (ConstantInt *TripCountC = dyn_cast<ConstantInt>(TripCount)) { - // Guard against huge trip counts. - if (TripCountC->getValue().getActiveBits() <= 32) { - return (unsigned)TripCountC->getZExtValue(); - } - } - } - return 0; - } - - /// getSmallConstantTripMultiple - Returns the largest constant divisor of the - /// trip count of this loop as a normal unsigned value, if possible. This - /// means that the actual trip count is always a multiple of the returned - /// value (don't forget the trip count could very well be zero as well!). - /// - /// Returns 1 if the trip count is unknown or not guaranteed to be the - /// multiple of a constant (which is also the case if the trip count is simply - /// constant, use getSmallConstantTripCount for that case), Will also return 1 - /// if the trip count is very large (>= 2^32). - inline unsigned getSmallConstantTripMultiple() const { - Value* TripCount = this->getTripCount(); - // This will hold the ConstantInt result, if any - ConstantInt *Result = NULL; - if (TripCount) { - // See if the trip count is constant itself - Result = dyn_cast<ConstantInt>(TripCount); - // if not, see if it is a multiplication - if (!Result) - if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TripCount)) { - switch (BO->getOpcode()) { - case BinaryOperator::Mul: - Result = dyn_cast<ConstantInt>(BO->getOperand(1)); - break; - default: - break; - } - } - } - // Guard against huge trip counts. - if (Result && Result->getValue().getActiveBits() <= 32) { - return (unsigned)Result->getZExtValue(); - } else { - return 1; - } - } - - /// isLCSSAForm - Return true if the Loop is in LCSSA form - inline bool isLCSSAForm() const { - // Sort the blocks vector so that we can use binary search to do quick - // lookups. - SmallPtrSet<BlockT*, 16> LoopBBs(block_begin(), block_end()); - - for (block_iterator BI = block_begin(), E = block_end(); BI != E; ++BI) { - BlockT *BB = *BI; - for (typename BlockT::iterator I = BB->begin(), E = BB->end(); I != E;++I) - for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; - ++UI) { - BlockT *UserBB = cast<Instruction>(*UI)->getParent(); - if (PHINode *P = dyn_cast<PHINode>(*UI)) { - UserBB = P->getIncomingBlock(UI); - } - - // Check the current block, as a fast-path. Most values are used in - // the same block they are defined in. - if (UserBB != BB && !LoopBBs.count(UserBB)) - return false; - } - } - - return true; - } //===--------------------------------------------------------------------===// // APIs for updating loop information after changing the CFG @@ -538,39 +306,39 @@ public: /// 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> &LI); + 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(LoopBase<BlockT> *OldChild, - LoopBase<BlockT> *NewChild) { + void replaceChildLoopWith(LoopT *OldChild, + LoopT *NewChild) { assert(OldChild->ParentLoop == this && "This loop is already broken!"); assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!"); - typename std::vector<LoopBase<BlockT>*>::iterator I = + typename std::vector<LoopT *>::iterator I = std::find(SubLoops.begin(), SubLoops.end(), OldChild); assert(I != SubLoops.end() && "OldChild not in loop!"); *I = NewChild; OldChild->ParentLoop = 0; - NewChild->ParentLoop = this; + NewChild->ParentLoop = static_cast<LoopT *>(this); } /// addChildLoop - Add the specified loop to be a child of this loop. This /// updates the loop depth of the new child. /// - void addChildLoop(LoopBase<BlockT> *NewChild) { + void addChildLoop(LoopT *NewChild) { assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!"); - NewChild->ParentLoop = this; + 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. - LoopBase<BlockT> *removeChildLoop(iterator I) { + LoopT *removeChildLoop(iterator I) { assert(I != SubLoops.end() && "Cannot remove end iterator!"); - LoopBase<BlockT> *Child = *I; + LoopT *Child = *I; assert(Child->ParentLoop == this && "Child is not a child of this loop!"); SubLoops.erase(SubLoops.begin()+(I-begin())); Child->ParentLoop = 0; @@ -609,16 +377,86 @@ public: /// verifyLoop - Verify loop structure void verifyLoop() const { #ifndef NDEBUG - assert (getHeader() && "Loop header is missing"); - assert (getLoopPreheader() && "Loop preheader is missing"); - assert (getLoopLatch() && "Loop latch is missing"); - for (iterator I = SubLoops.begin(), E = SubLoops.end(); I != E; ++I) - (*I)->verifyLoop(); + assert(!Blocks.empty() && "Loop header is missing"); + + // Sort the blocks vector so that we can use binary search to do quick + // lookups. + SmallVector<BlockT*, 128> LoopBBs(block_begin(), block_end()); + std::sort(LoopBBs.begin(), LoopBBs.end()); + + // Check the individual blocks. + for (block_iterator I = block_begin(), E = block_end(); I != E; ++I) { + BlockT *BB = *I; + bool HasInsideLoopSuccs = false; + bool HasInsideLoopPreds = false; + SmallVector<BlockT *, 2> OutsideLoopPreds; + + typedef GraphTraits<BlockT*> BlockTraits; + for (typename BlockTraits::ChildIteratorType SI = + BlockTraits::child_begin(BB), SE = BlockTraits::child_end(BB); + SI != SE; ++SI) + if (std::binary_search(LoopBBs.begin(), LoopBBs.end(), *SI)) { + HasInsideLoopSuccs = true; + break; + } + typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits; + for (typename InvBlockTraits::ChildIteratorType PI = + InvBlockTraits::child_begin(BB), PE = InvBlockTraits::child_end(BB); + PI != PE; ++PI) { + if (std::binary_search(LoopBBs.begin(), LoopBBs.end(), *PI)) + HasInsideLoopPreds = true; + else + OutsideLoopPreds.push_back(*PI); + } + + if (BB == getHeader()) { + assert(!OutsideLoopPreds.empty() && "Loop is unreachable!"); + } else if (!OutsideLoopPreds.empty()) { + // A non-header loop shouldn't be reachable from outside the loop, + // though it is permitted if the predecessor is not itself actually + // reachable. + BlockT *EntryBB = BB->getParent()->begin(); + for (df_iterator<BlockT *> NI = df_begin(EntryBB), + NE = df_end(EntryBB); NI != NE; ++NI) + for (unsigned i = 0, e = OutsideLoopPreds.size(); i != e; ++i) + assert(*NI != OutsideLoopPreds[i] && + "Loop has multiple entry points!"); + } + assert(HasInsideLoopPreds && "Loop block has no in-loop predecessors!"); + assert(HasInsideLoopSuccs && "Loop block has no in-loop successors!"); + assert(BB != getHeader()->getParent()->begin() && + "Loop contains function entry block!"); + } + + // Check the subloops. + for (iterator I = begin(), E = end(); I != E; ++I) + // Each block in each subloop should be contained within this loop. + for (block_iterator BI = (*I)->block_begin(), BE = (*I)->block_end(); + BI != BE; ++BI) { + assert(std::binary_search(LoopBBs.begin(), LoopBBs.end(), *BI) && + "Loop does not contain all the blocks of a subloop!"); + } + + // Check the parent loop pointer. + if (ParentLoop) { + assert(std::find(ParentLoop->begin(), ParentLoop->end(), this) != + ParentLoop->end() && + "Loop is not a subloop of its parent!"); + } #endif } - void print(std::ostream &OS, unsigned Depth = 0) const { - OS << std::string(Depth*2, ' ') << "Loop at depth " << getLoopDepth() + /// verifyLoop - Verify loop structure of this loop and all nested loops. + void verifyLoopNest() const { + // Verify this loop. + verifyLoop(); + // Verify the subloops. + for (iterator I = begin(), E = end(); I != E; ++I) + (*I)->verifyLoopNest(); + } + + void print(raw_ostream &OS, unsigned Depth = 0) const { + OS.indent(Depth*2) << "Loop at depth " << getLoopDepth() << " containing: "; for (unsigned i = 0; i < getBlocks().size(); ++i) { @@ -635,33 +473,131 @@ public: (*I)->print(OS, Depth+2); } - void print(std::ostream *O, unsigned Depth = 0) const { - if (O) print(*O, Depth); - } - void dump() const { - print(cerr); + print(errs()); } -private: - friend class LoopInfoBase<BlockT>; +protected: + friend class LoopInfoBase<BlockT, LoopT>; explicit LoopBase(BlockT *BB) : ParentLoop(0) { Blocks.push_back(BB); } }; +class Loop : public LoopBase<BasicBlock, Loop> { +public: + Loop() {} + + /// isLoopInvariant - Return true if the specified value is loop invariant + /// + bool isLoopInvariant(Value *V) const; + + /// isLoopInvariant - Return true if the specified instruction is + /// loop-invariant. + /// + bool isLoopInvariant(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 = 0) 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 = 0) 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; + + /// getCanonicalInductionVariableIncrement - Return the LLVM value that holds + /// the canonical induction variable value for the "next" iteration of the + /// loop. This always succeeds if getCanonicalInductionVariable succeeds. + /// + Instruction *getCanonicalInductionVariableIncrement() const; + + /// getTripCount - Return a loop-invariant LLVM value indicating the number of + /// times the loop will be executed. Note that this means that the backedge + /// of the loop executes N-1 times. If the trip-count cannot be determined, + /// this returns null. + /// + /// The IndVarSimplify pass transforms loops to have a form that this + /// function easily understands. + /// + Value *getTripCount() const; + + /// getSmallConstantTripCount - Returns the trip count of this loop as a + /// normal unsigned value, if possible. Returns 0 if the trip count is unknown + /// of not constant. Will also return 0 if the trip count is very large + /// (>= 2^32) + unsigned getSmallConstantTripCount() const; + + /// getSmallConstantTripMultiple - Returns the largest constant divisor of the + /// trip count of this loop as a normal unsigned value, if possible. This + /// means that the actual trip count is always a multiple of the returned + /// value (don't forget the trip count could very well be zero as well!). + /// + /// Returns 1 if the trip count is unknown or not guaranteed to be the + /// multiple of a constant (which is also the case if the trip count is simply + /// constant, use getSmallConstantTripCount for that case), Will also return 1 + /// if the trip count is very large (>= 2^32). + unsigned getSmallConstantTripMultiple() const; + + /// isLCSSAForm - Return true if the Loop is in LCSSA form + bool isLCSSAForm() 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; + + /// 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 is 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; + +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> +template<class BlockT, class LoopT> class LoopInfoBase { // BBMap - Mapping of basic blocks to the inner most loop they occur in - std::map<BlockT*, LoopBase<BlockT>*> BBMap; - std::vector<LoopBase<BlockT>*> TopLevelLoops; - friend class LoopBase<BlockT>; + std::map<BlockT *, LoopT *> BBMap; + std::vector<LoopT *> TopLevelLoops; + friend class LoopBase<BlockT, LoopT>; void operator=(const LoopInfoBase &); // do not implement LoopInfoBase(const LoopInfo &); // do not implement @@ -670,7 +606,7 @@ public: ~LoopInfoBase() { releaseMemory(); } void releaseMemory() { - for (typename std::vector<LoopBase<BlockT>* >::iterator I = + for (typename std::vector<LoopT *>::iterator I = TopLevelLoops.begin(), E = TopLevelLoops.end(); I != E; ++I) delete *I; // Delete all of the loops... @@ -681,7 +617,7 @@ public: /// iterator/begin/end - The interface to the top-level loops in the current /// function. /// - typedef typename std::vector<LoopBase<BlockT>*>::const_iterator iterator; + typedef typename std::vector<LoopT *>::const_iterator iterator; iterator begin() const { return TopLevelLoops.begin(); } iterator end() const { return TopLevelLoops.end(); } bool empty() const { return TopLevelLoops.empty(); } @@ -689,15 +625,15 @@ public: /// 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. /// - LoopBase<BlockT> *getLoopFor(const BlockT *BB) const { - typename std::map<BlockT *, LoopBase<BlockT>*>::const_iterator I= + LoopT *getLoopFor(const BlockT *BB) const { + typename std::map<BlockT *, LoopT *>::const_iterator I= BBMap.find(const_cast<BlockT*>(BB)); return I != BBMap.end() ? I->second : 0; } /// operator[] - same as getLoopFor... /// - const LoopBase<BlockT> *operator[](const BlockT *BB) const { + const LoopT *operator[](const BlockT *BB) const { return getLoopFor(BB); } @@ -705,22 +641,22 @@ public: /// depth of 0 means the block is not inside any loop. /// unsigned getLoopDepth(const BlockT *BB) const { - const LoopBase<BlockT> *L = getLoopFor(BB); + 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 LoopBase<BlockT> *L = getLoopFor(BB); + 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. - LoopBase<BlockT> *removeLoop(iterator I) { + LoopT *removeLoop(iterator I) { assert(I != end() && "Cannot remove end iterator!"); - LoopBase<BlockT> *L = *I; + LoopT *L = *I; assert(L->getParentLoop() == 0 && "Not a top-level loop!"); TopLevelLoops.erase(TopLevelLoops.begin() + (I-begin())); return L; @@ -729,17 +665,17 @@ public: /// 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, LoopBase<BlockT> *L) { - LoopBase<BlockT> *&OldLoop = BBMap[BB]; + void changeLoopFor(BlockT *BB, LoopT *L) { + LoopT *&OldLoop = BBMap[BB]; assert(OldLoop && "Block not in a loop yet!"); OldLoop = L; } /// changeTopLevelLoop - Replace the specified loop in the top-level loops /// list with the indicated loop. - void changeTopLevelLoop(LoopBase<BlockT> *OldLoop, - LoopBase<BlockT> *NewLoop) { - typename std::vector<LoopBase<BlockT>*>::iterator I = + void changeTopLevelLoop(LoopT *OldLoop, + LoopT *NewLoop) { + typename std::vector<LoopT *>::iterator I = std::find(TopLevelLoops.begin(), TopLevelLoops.end(), OldLoop); assert(I != TopLevelLoops.end() && "Old loop not at top level!"); *I = NewLoop; @@ -749,7 +685,7 @@ public: /// addTopLevelLoop - This adds the specified loop to the collection of /// top-level loops. - void addTopLevelLoop(LoopBase<BlockT> *New) { + void addTopLevelLoop(LoopT *New) { assert(New->getParentLoop() == 0 && "Loop already in subloop!"); TopLevelLoops.push_back(New); } @@ -758,9 +694,9 @@ public: /// including all of the Loop objects it is nested in and our mapping from /// BasicBlocks to loops. void removeBlock(BlockT *BB) { - typename std::map<BlockT *, LoopBase<BlockT>*>::iterator I = BBMap.find(BB); + typename std::map<BlockT *, LoopT *>::iterator I = BBMap.find(BB); if (I != BBMap.end()) { - for (LoopBase<BlockT> *L = I->second; L; L = L->getParentLoop()) + for (LoopT *L = I->second; L; L = L->getParentLoop()) L->removeBlockFromLoop(BB); BBMap.erase(I); @@ -769,8 +705,8 @@ public: // Internals - static bool isNotAlreadyContainedIn(const LoopBase<BlockT> *SubLoop, - const LoopBase<BlockT> *ParentLoop) { + static bool isNotAlreadyContainedIn(const LoopT *SubLoop, + const LoopT *ParentLoop) { if (SubLoop == 0) return true; if (SubLoop == ParentLoop) return false; return isNotAlreadyContainedIn(SubLoop->getParentLoop(), ParentLoop); @@ -781,11 +717,11 @@ public: for (df_iterator<BlockT*> NI = df_begin(RootNode), NE = df_end(RootNode); NI != NE; ++NI) - if (LoopBase<BlockT> *L = ConsiderForLoop(*NI, DT)) + if (LoopT *L = ConsiderForLoop(*NI, DT)) TopLevelLoops.push_back(L); } - LoopBase<BlockT> *ConsiderForLoop(BlockT *BB, DominatorTreeBase<BlockT> &DT) { + LoopT *ConsiderForLoop(BlockT *BB, DominatorTreeBase<BlockT> &DT) { if (BBMap.find(BB) != BBMap.end()) return 0;// Haven't processed this node? std::vector<BlockT *> TodoStack; @@ -796,13 +732,13 @@ public: for (typename InvBlockTraits::ChildIteratorType I = InvBlockTraits::child_begin(BB), E = InvBlockTraits::child_end(BB); I != E; ++I) - if (DT.dominates(BB, *I)) // If BB dominates it's predecessor... + if (DT.dominates(BB, *I)) // If BB dominates its predecessor... TodoStack.push_back(*I); if (TodoStack.empty()) return 0; // No backedges to this block... // Create a new loop to represent this basic block... - LoopBase<BlockT> *L = new LoopBase<BlockT>(BB); + LoopT *L = new LoopT(BB); BBMap[BB] = L; BlockT *EntryBlock = BB->getParent()->begin(); @@ -819,13 +755,13 @@ public: // occurs, this child loop gets added to a part of the current loop, // making it a sibling to the current loop. We have to reparent this // loop. - if (LoopBase<BlockT> *SubLoop = - const_cast<LoopBase<BlockT>*>(getLoopFor(X))) + if (LoopT *SubLoop = + const_cast<LoopT *>(getLoopFor(X))) if (SubLoop->getHeader() == X && isNotAlreadyContainedIn(SubLoop, L)){ - // Remove the subloop from it's current parent... + // Remove the subloop from its current parent... assert(SubLoop->ParentLoop && SubLoop->ParentLoop != L); - LoopBase<BlockT> *SLP = SubLoop->ParentLoop; // SubLoopParent - typename std::vector<LoopBase<BlockT>*>::iterator I = + LoopT *SLP = SubLoop->ParentLoop; // SubLoopParent + typename std::vector<LoopT *>::iterator I = std::find(SLP->SubLoops.begin(), SLP->SubLoops.end(), SubLoop); assert(I != SLP->SubLoops.end() &&"SubLoop not a child of parent?"); SLP->SubLoops.erase(I); // Remove from parent... @@ -849,7 +785,7 @@ public: // If there are any loops nested within this loop, create them now! for (typename std::vector<BlockT*>::iterator I = L->Blocks.begin(), E = L->Blocks.end(); I != E; ++I) - if (LoopBase<BlockT> *NewLoop = ConsiderForLoop(*I, DT)) { + if (LoopT *NewLoop = ConsiderForLoop(*I, DT)) { L->SubLoops.push_back(NewLoop); NewLoop->ParentLoop = L; } @@ -858,25 +794,20 @@ public: // loop can be found for them. // for (typename std::vector<BlockT*>::iterator I = L->Blocks.begin(), - E = L->Blocks.end(); I != E; ++I) { - typename std::map<BlockT*, LoopBase<BlockT>*>::iterator BBMI = - BBMap.find(*I); - if (BBMI == BBMap.end()) // Not in map yet... - BBMap.insert(BBMI, std::make_pair(*I, L)); // Must be at this level - } + E = L->Blocks.end(); I != E; ++I) + BBMap.insert(std::make_pair(*I, L)); // Now that we have a list of all of the child loops of this loop, check to // see if any of them should actually be nested inside of each other. We // can accidentally pull loops our of their parents, so we must make sure to // organize the loop nests correctly now. { - std::map<BlockT*, LoopBase<BlockT>*> ContainingLoops; + std::map<BlockT *, LoopT *> ContainingLoops; for (unsigned i = 0; i != L->SubLoops.size(); ++i) { - LoopBase<BlockT> *Child = L->SubLoops[i]; + LoopT *Child = L->SubLoops[i]; assert(Child->getParentLoop() == L && "Not proper child loop?"); - if (LoopBase<BlockT> *ContainingLoop = - ContainingLoops[Child->getHeader()]) { + if (LoopT *ContainingLoop = ContainingLoops[Child->getHeader()]) { // If there is already a loop which contains this loop, move this loop // into the containing loop. MoveSiblingLoopInto(Child, ContainingLoop); @@ -886,11 +817,11 @@ public: // if any of the contained blocks are loop headers for subloops we // have already processed. for (unsigned b = 0, e = Child->Blocks.size(); b != e; ++b) { - LoopBase<BlockT> *&BlockLoop = ContainingLoops[Child->Blocks[b]]; + LoopT *&BlockLoop = ContainingLoops[Child->Blocks[b]]; if (BlockLoop == 0) { // Child block not processed yet... BlockLoop = Child; } else if (BlockLoop != Child) { - LoopBase<BlockT> *SubLoop = BlockLoop; + LoopT *SubLoop = BlockLoop; // Reparent all of the blocks which used to belong to BlockLoops for (unsigned j = 0, e = SubLoop->Blocks.size(); j != e; ++j) ContainingLoops[SubLoop->Blocks[j]] = Child; @@ -911,14 +842,14 @@ public: /// MoveSiblingLoopInto - This method moves the NewChild loop to live inside /// of the NewParent Loop, instead of being a sibling of it. - void MoveSiblingLoopInto(LoopBase<BlockT> *NewChild, - LoopBase<BlockT> *NewParent) { - LoopBase<BlockT> *OldParent = NewChild->getParentLoop(); + void MoveSiblingLoopInto(LoopT *NewChild, + LoopT *NewParent) { + LoopT *OldParent = NewChild->getParentLoop(); assert(OldParent && OldParent == NewParent->getParentLoop() && NewChild != NewParent && "Not sibling loops!"); // Remove NewChild from being a child of OldParent - typename std::vector<LoopBase<BlockT>*>::iterator I = + typename std::vector<LoopT *>::iterator I = std::find(OldParent->SubLoops.begin(), OldParent->SubLoops.end(), NewChild); assert(I != OldParent->SubLoops.end() && "Parent fields incorrect??"); @@ -931,7 +862,7 @@ public: /// InsertLoopInto - This inserts loop L into the specified parent loop. If /// the parent loop contains a loop which should contain L, the loop gets /// inserted into L instead. - void InsertLoopInto(LoopBase<BlockT> *L, LoopBase<BlockT> *Parent) { + void InsertLoopInto(LoopT *L, LoopT *Parent) { BlockT *LHeader = L->getHeader(); assert(Parent->contains(LHeader) && "This loop should not be inserted here!"); @@ -951,11 +882,11 @@ public: // Debugging - void print(std::ostream &OS, const Module* ) const { + void print(raw_ostream &OS) const { for (unsigned i = 0; i < TopLevelLoops.size(); ++i) TopLevelLoops[i]->print(OS); #if 0 - for (std::map<BasicBlock*, Loop*>::const_iterator I = BBMap.begin(), + for (std::map<BasicBlock*, LoopT*>::const_iterator I = BBMap.begin(), E = BBMap.end(); I != E; ++I) OS << "BB '" << I->first->getName() << "' level = " << I->second->getLoopDepth() << "\n"; @@ -964,8 +895,8 @@ public: }; class LoopInfo : public FunctionPass { - LoopInfoBase<BasicBlock> LI; - friend class LoopBase<BasicBlock>; + LoopInfoBase<BasicBlock, Loop> LI; + friend class LoopBase<BasicBlock, Loop>; void operator=(const LoopInfo &); // do not implement LoopInfo(const LoopInfo &); // do not implement @@ -974,12 +905,12 @@ public: LoopInfo() : FunctionPass(&ID) {} - LoopInfoBase<BasicBlock>& getBase() { return LI; } + LoopInfoBase<BasicBlock, Loop>& getBase() { return LI; } /// iterator/begin/end - The interface to the top-level loops in the current /// function. /// - typedef LoopInfoBase<BasicBlock>::iterator iterator; + typedef LoopInfoBase<BasicBlock, Loop>::iterator iterator; inline iterator begin() const { return LI.begin(); } inline iterator end() const { return LI.end(); } bool empty() const { return LI.empty(); } @@ -1013,12 +944,12 @@ public: /// virtual bool runOnFunction(Function &F); - virtual void releaseMemory() { LI.releaseMemory(); } + virtual void verifyAnalysis() const; - virtual void print(std::ostream &O, const Module* M = 0) const { - LI.print(O, M); - } + 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 @@ -1051,6 +982,13 @@ public: void removeBlock(BasicBlock *BB) { LI.removeBlock(BB); } + + static bool isNotAlreadyContainedIn(const Loop *SubLoop, + const Loop *ParentLoop) { + return + LoopInfoBase<BasicBlock, Loop>::isNotAlreadyContainedIn(SubLoop, + ParentLoop); + } }; @@ -1081,19 +1019,21 @@ template <> struct GraphTraits<Loop*> { } }; -template<class BlockT> -void LoopBase<BlockT>::addBasicBlockToLoop(BlockT *NewBB, - LoopInfoBase<BlockT> &LIB) { +template<class BlockT, class LoopT> +void +LoopBase<BlockT, LoopT>::addBasicBlockToLoop(BlockT *NewBB, + LoopInfoBase<BlockT, LoopT> &LIB) { assert((Blocks.empty() || LIB[getHeader()] == this) && "Incorrect LI specified for this loop!"); assert(NewBB && "Cannot add a null basic block to the loop!"); assert(LIB[NewBB] == 0 && "BasicBlock already in the loop!"); + LoopT *L = static_cast<LoopT *>(this); + // Add the loop mapping to the LoopInfo object... - LIB.BBMap[NewBB] = this; + LIB.BBMap[NewBB] = L; // Add the basic block to this loop and all parent loops... - LoopBase<BlockT> *L = this; while (L) { L->Blocks.push_back(NewBB); L = L->getParentLoop(); |
