diff options
| -rw-r--r-- | include/llvm/Analysis/LoopInfo.h | 370 | ||||
| -rw-r--r-- | lib/Analysis/LoopInfo.cpp | 231 |
2 files changed, 334 insertions, 267 deletions
diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h index 32115aea3f..f8748e4960 100644 --- a/include/llvm/Analysis/LoopInfo.h +++ b/include/llvm/Analysis/LoopInfo.h @@ -33,9 +33,11 @@ #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 <algorithm> @@ -54,6 +56,7 @@ class DominatorTree; class LoopInfo; class PHINode; class Instruction; +template<class N> class LoopInfoBase; //===----------------------------------------------------------------------===// /// LoopBase class - Instances of this class are used to represent loops that are @@ -513,7 +516,7 @@ public: } private: - friend class LoopInfo; + friend class LoopInfoBase<BlockT>; LoopBase(BlockT *BB) : ParentLoop(0) { Blocks.push_back(BB); } @@ -526,61 +529,352 @@ typedef LoopBase<BasicBlock> Loop; /// LoopInfo - This class builds and contains all of the top level loop /// structures in the specified function. /// -class LoopInfo : public FunctionPass { + +template<class BlockT> +class LoopInfoBase { // BBMap - Mapping of basic blocks to the inner most loop they occur in - std::map<BasicBlock*, Loop*> BBMap; - std::vector<Loop*> TopLevelLoops; - friend class LoopBase<BasicBlock>; + std::map<BlockT*, Loop*> BBMap; + std::vector<LoopBase<BlockT>*> TopLevelLoops; + friend class LoopBase<BlockT>; + public: - static char ID; // Pass identification, replacement for typeid - - LoopInfo() : FunctionPass(intptr_t(&ID)) {} - ~LoopInfo() { releaseMemory(); } + LoopInfoBase() { } + ~LoopInfoBase() { releaseMemory(); } + + void releaseMemory() { + for (typename std::vector<LoopBase<BlockT>* >::iterator I = + TopLevelLoops.begin(), E = TopLevelLoops.end(); I != E; ++I) + delete *I; // Delete all of the loops... + BBMap.clear(); // Reset internal state of analysis + TopLevelLoops.clear(); + } + /// iterator/begin/end - The interface to the top-level loops in the current /// function. /// - typedef std::vector<Loop*>::const_iterator iterator; + typedef typename std::vector<LoopBase<BlockT>*>::const_iterator iterator; iterator begin() const { return TopLevelLoops.begin(); } iterator end() const { return TopLevelLoops.end(); } - + /// 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. /// - Loop *getLoopFor(const BasicBlock *BB) const { - std::map<BasicBlock *, Loop*>::const_iterator I= + LoopBase<BlockT> *getLoopFor(const BlockT *BB) const { + typename std::map<BlockT *, LoopBase<BlockT>*>::const_iterator I= BBMap.find(const_cast<BasicBlock*>(BB)); return I != BBMap.end() ? I->second : 0; } - + /// operator[] - same as getLoopFor... /// - const Loop *operator[](const BasicBlock *BB) const { + const LoopBase<BlockT> *operator[](const BlockT *BB) const { return getLoopFor(BB); } - + /// getLoopDepth - Return the loop nesting level of the specified block... /// - unsigned getLoopDepth(const BasicBlock *BB) const { + unsigned getLoopDepth(const BlockT *BB) const { const Loop *L = getLoopFor(BB); return L ? L->getLoopDepth() : 0; } // isLoopHeader - True if the block is a loop header node - bool isLoopHeader(BasicBlock *BB) const { + bool isLoopHeader(BlockT *BB) const { const Loop *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) { + assert(I != end() && "Cannot remove end iterator!"); + LoopBase<BlockT> *L = *I; + assert(L->getParentLoop() == 0 && "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, LoopBase<BlockT> *L) { + LoopBase<BlockT> *&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 = + 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 && + "Loops already embedded into a subloop!"); + } + + /// addTopLevelLoop - This adds the specified loop to the collection of + /// top-level loops. + void addTopLevelLoop(LoopBase<BlockT> *New) { + assert(New->getParentLoop() == 0 && "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) { + typename std::map<BlockT *, LoopBase<BlockT>*>::iterator I = BBMap.find(BB); + if (I != BBMap.end()) { + for (Loop *L = I->second; L; L = L->getParentLoop()) + L->removeBlockFromLoop(BB); + + BBMap.erase(I); + } + } + + // Internals + + static bool isNotAlreadyContainedIn(Loop *SubLoop, Loop *ParentLoop) { + if (SubLoop == 0) return true; + if (SubLoop == ParentLoop) return false; + return isNotAlreadyContainedIn(SubLoop->getParentLoop(), ParentLoop); + } + + void Calculate(DominatorTree &DT) { + BlockT *RootNode = DT.getRootNode()->getBlock(); + + for (df_iterator<BlockT*> NI = df_begin(RootNode), + NE = df_end(RootNode); NI != NE; ++NI) + if (LoopBase<BlockT> *L = ConsiderForLoop(*NI, DT)) + TopLevelLoops.push_back(L); + } + + LoopBase<BlockT> *ConsiderForLoop(BlockT *BB, DominatorTree &DT) { + if (BBMap.find(BB) != BBMap.end()) return 0;// Haven't processed this node? + + std::vector<BlockT *> TodoStack; + + // Scan the predecessors of BB, checking to see if BB dominates any of + // them. This identifies backedges which target this node... + for (pred_iterator I = pred_begin(BB), E = pred_end(BB); I != E; ++I) + if (DT.dominates(BB, *I)) // If BB dominates it's 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); + BBMap[BB] = L; + + BlockT *EntryBlock = &BB->getParent()->getEntryBlock(); + + while (!TodoStack.empty()) { // Process all the nodes in the loop + BlockT *X = TodoStack.back(); + TodoStack.pop_back(); + + if (!L->contains(X) && // As of yet unprocessed?? + DT.dominates(EntryBlock, X)) { // X is reachable from entry block? + // Check to see if this block already belongs to a loop. If this occurs + // then we have a case where a loop that is supposed to be a child of the + // current loop was processed before the current loop. When this 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 (SubLoop->getHeader() == X && isNotAlreadyContainedIn(SubLoop, L)) { + // Remove the subloop from it's current parent... + assert(SubLoop->ParentLoop && SubLoop->ParentLoop != L); + LoopBase<BlockT> *SLP = SubLoop->ParentLoop; // SubLoopParent + typename std::vector<LoopBase<BlockT>*>::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... + + // Add the subloop to THIS loop... + SubLoop->ParentLoop = L; + L->SubLoops.push_back(SubLoop); + } + + // Normal case, add the block to our loop... + L->Blocks.push_back(X); + + // Add all of the predecessors of X to the end of the work stack... + TodoStack.insert(TodoStack.end(), pred_begin(X), pred_end(X)); + } + } + + // 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)) { + L->SubLoops.push_back(NewLoop); + NewLoop->ParentLoop = L; + } + + // Add the basic blocks that comprise this loop to the BBMap so that this + // 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.lower_bound(*I); + if (BBMI == BBMap.end() || BBMI->first != *I) // Not in map yet... + BBMap.insert(BBMI, std::make_pair(*I, L)); // Must be at this level + } + + // 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; + for (unsigned i = 0; i != L->SubLoops.size(); ++i) { + LoopBase<BlockT> *Child = L->SubLoops[i]; + assert(Child->getParentLoop() == L && "Not proper child loop?"); + + if (LoopBase<BlockT> *ContainingLoop = + ContainingLoops[Child->getHeader()]) { + // If there is already a loop which contains this loop, move this loop + // into the containing loop. + MoveSiblingLoopInto(Child, ContainingLoop); + --i; // The loop got removed from the SubLoops list. + } else { + // This is currently considered to be a top-level loop. Check to see 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]]; + if (BlockLoop == 0) { // Child block not processed yet... + BlockLoop = Child; + } else if (BlockLoop != Child) { + LoopBase<BlockT> *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; + + // There is already a loop which contains this block, that means + // that we should reparent the loop which the block is currently + // considered to belong to to be a child of this loop. + MoveSiblingLoopInto(SubLoop, Child); + --i; // We just shrunk the SubLoops list. + } + } + } + } + } + + return L; + } + + /// 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(); + 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 = + std::find(OldParent->SubLoops.begin(), OldParent->SubLoops.end(), NewChild); + assert(I != OldParent->SubLoops.end() && "Parent fields incorrect??"); + OldParent->SubLoops.erase(I); // Remove from parent's subloops list + NewChild->ParentLoop = 0; + + InsertLoopInto(NewChild, NewParent); + } + + /// 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) { + BlockT *LHeader = L->getHeader(); + assert(Parent->contains(LHeader) && "This loop should not be inserted here!"); + + // Check to see if it belongs in a child loop... + for (unsigned i = 0, e = Parent->SubLoops.size(); i != e; ++i) + if (Parent->SubLoops[i]->contains(LHeader)) { + InsertLoopInto(L, Parent->SubLoops[i]); + return; + } + + // If not, insert it here! + Parent->SubLoops.push_back(L); + L->ParentLoop = Parent; + } + + // Debugging + + void print(std::ostream &OS, const Module* ) 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(), + E = BBMap.end(); I != E; ++I) + OS << "BB '" << I->first->getName() << "' level = " + << I->second->getLoopDepth() << "\n"; + #endif + } +}; + +class LoopInfo : public FunctionPass { + LoopInfoBase<BasicBlock>* LI; + friend class LoopBase<BasicBlock>; + + LoopInfoBase<BasicBlock>& getBase() { return *LI; } +public: + static char ID; // Pass identification, replacement for typeid + + LoopInfo() : FunctionPass(intptr_t(&ID)) { + LI = new LoopInfoBase<BasicBlock>(); + } + + ~LoopInfo() { LI->releaseMemory(); } + + /// iterator/begin/end - The interface to the top-level loops in the current + /// function. + /// + typedef std::vector<Loop*>::const_iterator iterator; + inline iterator begin() const { return LI->begin(); } + inline iterator end() const { return LI->end(); } + + /// 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); + } + + /// getLoopDepth - Return the loop nesting level of the specified block... + /// + inline unsigned getLoopDepth(const BasicBlock *BB) const { + return LI->getLoopDepth(BB); + } + + // 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 releaseMemory(); + virtual void releaseMemory() { LI->releaseMemory(); } - void print(std::ostream &O, const Module* = 0) const; - void print(std::ostream *O, const Module* M = 0) const { - if (O) print(*O, M); + virtual void print(std::ostream &O, const Module* M = 0) const { + if (O) LI->print(O, M); } virtual void getAnalysisUsage(AnalysisUsage &AU) const; @@ -588,34 +882,33 @@ public: /// 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. - Loop *removeLoop(iterator I); + 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. - void changeLoopFor(BasicBlock *BB, Loop *L); + 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. - void changeTopLevelLoop(Loop *OldLoop, Loop *NewLoop); + inline void changeTopLevelLoop(Loop *OldLoop, Loop *NewLoop) { + LI->changeTopLevelLoop(OldLoop, NewLoop); + } /// addTopLevelLoop - This adds the specified loop to the collection of /// top-level loops. - void addTopLevelLoop(Loop *New) { - assert(New->getParentLoop() == 0 && "Loop already in subloop!"); - TopLevelLoops.push_back(New); + 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); - -private: - void Calculate(DominatorTree &DT); - Loop *ConsiderForLoop(BasicBlock *BB, DominatorTree &DT); - void MoveSiblingLoopInto(Loop *NewChild, Loop *NewParent); - void InsertLoopInto(Loop *L, Loop *Parent); + void removeBlock(BasicBlock *BB) { + LI->removeBlock(BB); + } }; @@ -647,14 +940,17 @@ template <> struct GraphTraits<Loop*> { }; template<class BlockT> -void LoopBase<BlockT>::addBasicBlockToLoop(BlockT *NewBB, LoopInfo &LI) { +void LoopBase<BlockT>::addBasicBlockToLoop(BlockT *NewBB, + LoopInfo &LI) { assert((Blocks.empty() || LI[getHeader()] == this) && "Incorrect LI specified for this loop!"); assert(NewBB && "Cannot add a null basic block to the loop!"); assert(LI[NewBB] == 0 && "BasicBlock already in the loop!"); + LoopInfoBase<BasicBlock>& LIB = LI.getBase(); + // Add the loop mapping to the LoopInfo object... - LI.BBMap[NewBB] = this; + LIB.BBMap[NewBB] = this; // Add the basic block to this loop and all parent loops... LoopBase<BlockT> *L = this; diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp index 20ca892997..559f676806 100644 --- a/lib/Analysis/LoopInfo.cpp +++ b/lib/Analysis/LoopInfo.cpp @@ -43,243 +43,14 @@ X("loops", "Natural Loop Construction", true); // bool LoopInfo::runOnFunction(Function &) { releaseMemory(); - Calculate(getAnalysis<DominatorTree>()); // Update + LI->Calculate(getAnalysis<DominatorTree>()); // Update return false; } -void LoopInfo::releaseMemory() { - for (std::vector<Loop*>::iterator I = TopLevelLoops.begin(), - E = TopLevelLoops.end(); I != E; ++I) - delete *I; // Delete all of the loops... - - BBMap.clear(); // Reset internal state of analysis - TopLevelLoops.clear(); -} - -void LoopInfo::Calculate(DominatorTree &DT) { - BasicBlock *RootNode = DT.getRootNode()->getBlock(); - - for (df_iterator<BasicBlock*> NI = df_begin(RootNode), - NE = df_end(RootNode); NI != NE; ++NI) - if (Loop *L = ConsiderForLoop(*NI, DT)) - TopLevelLoops.push_back(L); -} - void LoopInfo::getAnalysisUsage(AnalysisUsage &AU) const { AU.setPreservesAll(); AU.addRequired<DominatorTree>(); } -void LoopInfo::print(std::ostream &OS, const Module* ) 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(), - E = BBMap.end(); I != E; ++I) - OS << "BB '" << I->first->getName() << "' level = " - << I->second->getLoopDepth() << "\n"; -#endif -} - -static bool isNotAlreadyContainedIn(Loop *SubLoop, Loop *ParentLoop) { - if (SubLoop == 0) return true; - if (SubLoop == ParentLoop) return false; - return isNotAlreadyContainedIn(SubLoop->getParentLoop(), ParentLoop); -} - -Loop *LoopInfo::ConsiderForLoop(BasicBlock *BB, DominatorTree &DT) { - if (BBMap.find(BB) != BBMap.end()) return 0; // Haven't processed this node? - - std::vector<BasicBlock *> TodoStack; - - // Scan the predecessors of BB, checking to see if BB dominates any of - // them. This identifies backedges which target this node... - for (pred_iterator I = pred_begin(BB), E = pred_end(BB); I != E; ++I) - if (DT.dominates(BB, *I)) // If BB dominates it's predecessor... - TodoStack.push_back(*I); - - if (TodoStack.empty()) return 0; // No backedges to this block... - - // Create a new loop to represent this basic block... - Loop *L = new Loop(BB); - BBMap[BB] = L; - - BasicBlock *EntryBlock = &BB->getParent()->getEntryBlock(); - - while (!TodoStack.empty()) { // Process all the nodes in the loop - BasicBlock *X = TodoStack.back(); - TodoStack.pop_back(); - - if (!L->contains(X) && // As of yet unprocessed?? - DT.dominates(EntryBlock, X)) { // X is reachable from entry block? - // Check to see if this block already belongs to a loop. If this occurs - // then we have a case where a loop that is supposed to be a child of the - // current loop was processed before the current loop. When this 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 (Loop *SubLoop = const_cast<Loop*>(getLoopFor(X))) - if (SubLoop->getHeader() == X && isNotAlreadyContainedIn(SubLoop, L)) { - // Remove the subloop from it's current parent... - assert(SubLoop->ParentLoop && SubLoop->ParentLoop != L); - Loop *SLP = SubLoop->ParentLoop; // SubLoopParent - std::vector<Loop*>::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... - - // Add the subloop to THIS loop... - SubLoop->ParentLoop = L; - L->SubLoops.push_back(SubLoop); - } - - // Normal case, add the block to our loop... - L->Blocks.push_back(X); - - // Add all of the predecessors of X to the end of the work stack... - TodoStack.insert(TodoStack.end(), pred_begin(X), pred_end(X)); - } - } - - // If there are any loops nested within this loop, create them now! - for (std::vector<BasicBlock*>::iterator I = L->Blocks.begin(), - E = L->Blocks.end(); I != E; ++I) - if (Loop *NewLoop = ConsiderForLoop(*I, DT)) { - L->SubLoops.push_back(NewLoop); - NewLoop->ParentLoop = L; - } - - // Add the basic blocks that comprise this loop to the BBMap so that this - // loop can be found for them. - // - for (std::vector<BasicBlock*>::iterator I = L->Blocks.begin(), - E = L->Blocks.end(); I != E; ++I) { - std::map<BasicBlock*, Loop*>::iterator BBMI = BBMap.lower_bound(*I); - if (BBMI == BBMap.end() || BBMI->first != *I) // Not in map yet... - BBMap.insert(BBMI, std::make_pair(*I, L)); // Must be at this level - } - - // 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<BasicBlock*, Loop*> ContainingLoops; - for (unsigned i = 0; i != L->SubLoops.size(); ++i) { - Loop *Child = L->SubLoops[i]; - assert(Child->getParentLoop() == L && "Not proper child loop?"); - - if (Loop *ContainingLoop = ContainingLoops[Child->getHeader()]) { - // If there is already a loop which contains this loop, move this loop - // into the containing loop. - MoveSiblingLoopInto(Child, ContainingLoop); - --i; // The loop got removed from the SubLoops list. - } else { - // This is currently considered to be a top-level loop. Check to see 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) { - Loop *&BlockLoop = ContainingLoops[Child->Blocks[b]]; - if (BlockLoop == 0) { // Child block not processed yet... - BlockLoop = Child; - } else if (BlockLoop != Child) { - Loop *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; - - // There is already a loop which contains this block, that means - // that we should reparent the loop which the block is currently - // considered to belong to to be a child of this loop. - MoveSiblingLoopInto(SubLoop, Child); - --i; // We just shrunk the SubLoops list. - } - } - } - } - } - - return L; -} - -/// MoveSiblingLoopInto - This method moves the NewChild loop to live inside of -/// the NewParent Loop, instead of being a sibling of it. -void LoopInfo::MoveSiblingLoopInto(Loop *NewChild, Loop *NewParent) { - Loop *OldParent = NewChild->getParentLoop(); - assert(OldParent && OldParent == NewParent->getParentLoop() && - NewChild != NewParent && "Not sibling loops!"); - - // Remove NewChild from being a child of OldParent - std::vector<Loop*>::iterator I = - std::find(OldParent->SubLoops.begin(), OldParent->SubLoops.end(), NewChild); - assert(I != OldParent->SubLoops.end() && "Parent fields incorrect??"); - OldParent->SubLoops.erase(I); // Remove from parent's subloops list - NewChild->ParentLoop = 0; - - InsertLoopInto(NewChild, NewParent); -} - -/// 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 LoopInfo::InsertLoopInto(Loop *L, Loop *Parent) { - BasicBlock *LHeader = L->getHeader(); - assert(Parent->contains(LHeader) && "This loop should not be inserted here!"); - - // Check to see if it belongs in a child loop... - for (unsigned i = 0, e = Parent->SubLoops.size(); i != e; ++i) - if (Parent->SubLoops[i]->contains(LHeader)) { - InsertLoopInto(L, Parent->SubLoops[i]); - return; - } - - // If not, insert it here! - Parent->SubLoops.push_back(L); - L->ParentLoop = Parent; -} - -/// 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 LoopInfo::changeLoopFor(BasicBlock *BB, Loop *L) { - Loop *&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 LoopInfo::changeTopLevelLoop(Loop *OldLoop, Loop *NewLoop) { - std::vector<Loop*>::iterator 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 && - "Loops already embedded into a subloop!"); -} - -/// 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. -Loop *LoopInfo::removeLoop(iterator I) { - assert(I != end() && "Cannot remove end iterator!"); - Loop *L = *I; - assert(L->getParentLoop() == 0 && "Not a top-level loop!"); - TopLevelLoops.erase(TopLevelLoops.begin() + (I-begin())); - return L; -} - -/// 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 LoopInfo::removeBlock(BasicBlock *BB) { - std::map<BasicBlock *, Loop*>::iterator I = BBMap.find(BB); - if (I != BBMap.end()) { - for (Loop *L = I->second; L; L = L->getParentLoop()) - L->removeBlockFromLoop(BB); - - BBMap.erase(I); - } -} - // Ensure this file gets linked when LoopInfo.h is used. DEFINING_FILE_FOR(LoopInfo) |