1193323Sed//===- llvm/Analysis/LoopInfo.h - Natural Loop Calculator -------*- C++ -*-===// 2193323Sed// 3193323Sed// The LLVM Compiler Infrastructure 4193323Sed// 5193323Sed// This file is distributed under the University of Illinois Open Source 6193323Sed// License. See LICENSE.TXT for details. 7193323Sed// 8193323Sed//===----------------------------------------------------------------------===// 9193323Sed// 10193323Sed// This file defines the LoopInfo class that is used to identify natural loops 11198090Srdivacky// and determine the loop depth of various nodes of the CFG. A natural loop 12198090Srdivacky// has exactly one entry-point, which is called the header. Note that natural 13193323Sed// loops may actually be several loops that share the same header node. 14193323Sed// 15193323Sed// This analysis calculates the nesting structure of loops in a function. For 16193323Sed// each natural loop identified, this analysis identifies natural loops 17193323Sed// contained entirely within the loop and the basic blocks the make up the loop. 18193323Sed// 19193323Sed// It can calculate on the fly various bits of information, for example: 20193323Sed// 21193323Sed// * whether there is a preheader for the loop 22193323Sed// * the number of back edges to the header 23193323Sed// * whether or not a particular block branches out of the loop 24193323Sed// * the successor blocks of the loop 25193323Sed// * the loop depth 26193323Sed// * etc... 27193323Sed// 28193323Sed//===----------------------------------------------------------------------===// 29193323Sed 30252723Sdim#ifndef LLVM_ANALYSIS_LOOPINFO_H 31252723Sdim#define LLVM_ANALYSIS_LOOPINFO_H 32193323Sed 33218893Sdim#include "llvm/ADT/DenseMap.h" 34226890Sdim#include "llvm/ADT/DenseSet.h" 35193323Sed#include "llvm/ADT/GraphTraits.h" 36193323Sed#include "llvm/ADT/SmallVector.h" 37193323Sed#include "llvm/Analysis/Dominators.h" 38252723Sdim#include "llvm/Pass.h" 39193323Sed#include <algorithm> 40193323Sed 41193323Sednamespace llvm { 42193323Sed 43193323Sedtemplate<typename T> 44245431Sdiminline void RemoveFromVector(std::vector<T*> &V, T *N) { 45193323Sed typename std::vector<T*>::iterator I = std::find(V.begin(), V.end(), N); 46193323Sed assert(I != V.end() && "N is not in this list!"); 47193323Sed V.erase(I); 48193323Sed} 49193323Sed 50193323Sedclass DominatorTree; 51193323Sedclass LoopInfo; 52198090Srdivackyclass Loop; 53263509Sdimclass MDNode; 54218893Sdimclass PHINode; 55252723Sdimclass raw_ostream; 56198090Srdivackytemplate<class N, class M> class LoopInfoBase; 57198090Srdivackytemplate<class N, class M> class LoopBase; 58193323Sed 59193323Sed//===----------------------------------------------------------------------===// 60193323Sed/// LoopBase class - Instances of this class are used to represent loops that 61193323Sed/// are detected in the flow graph 62193323Sed/// 63198090Srdivackytemplate<class BlockT, class LoopT> 64193323Sedclass LoopBase { 65198090Srdivacky LoopT *ParentLoop; 66193323Sed // SubLoops - Loops contained entirely within this one. 67198090Srdivacky std::vector<LoopT *> SubLoops; 68193323Sed 69193323Sed // Blocks - The list of blocks in this loop. First entry is the header node. 70193323Sed std::vector<BlockT*> Blocks; 71193323Sed 72263509Sdim SmallPtrSet<const BlockT*, 8> DenseBlockSet; 73263509Sdim 74245431Sdim LoopBase(const LoopBase<BlockT, LoopT> &) LLVM_DELETED_FUNCTION; 75245431Sdim const LoopBase<BlockT, LoopT>& 76245431Sdim operator=(const LoopBase<BlockT, LoopT> &) LLVM_DELETED_FUNCTION; 77193323Sedpublic: 78193323Sed /// Loop ctor - This creates an empty loop. 79193323Sed LoopBase() : ParentLoop(0) {} 80193323Sed ~LoopBase() { 81193323Sed for (size_t i = 0, e = SubLoops.size(); i != e; ++i) 82193323Sed delete SubLoops[i]; 83193323Sed } 84193323Sed 85193323Sed /// getLoopDepth - Return the nesting level of this loop. An outer-most 86193323Sed /// loop has depth 1, for consistency with loop depth values used for basic 87193323Sed /// blocks, where depth 0 is used for blocks not inside any loops. 88193323Sed unsigned getLoopDepth() const { 89193323Sed unsigned D = 1; 90198090Srdivacky for (const LoopT *CurLoop = ParentLoop; CurLoop; 91193323Sed CurLoop = CurLoop->ParentLoop) 92193323Sed ++D; 93193323Sed return D; 94193323Sed } 95193323Sed BlockT *getHeader() const { return Blocks.front(); } 96198090Srdivacky LoopT *getParentLoop() const { return ParentLoop; } 97193323Sed 98245431Sdim /// setParentLoop is a raw interface for bypassing addChildLoop. 99245431Sdim void setParentLoop(LoopT *L) { ParentLoop = L; } 100245431Sdim 101201360Srdivacky /// contains - Return true if the specified loop is contained within in 102201360Srdivacky /// this loop. 103193323Sed /// 104201360Srdivacky bool contains(const LoopT *L) const { 105201360Srdivacky if (L == this) return true; 106201360Srdivacky if (L == 0) return false; 107201360Srdivacky return contains(L->getParentLoop()); 108201360Srdivacky } 109226890Sdim 110201360Srdivacky /// contains - Return true if the specified basic block is in this loop. 111201360Srdivacky /// 112193323Sed bool contains(const BlockT *BB) const { 113263509Sdim return DenseBlockSet.count(BB); 114193323Sed } 115193323Sed 116201360Srdivacky /// contains - Return true if the specified instruction is in this loop. 117201360Srdivacky /// 118201360Srdivacky template<class InstT> 119201360Srdivacky bool contains(const InstT *Inst) const { 120201360Srdivacky return contains(Inst->getParent()); 121201360Srdivacky } 122201360Srdivacky 123193323Sed /// iterator/begin/end - Return the loops contained entirely within this loop. 124193323Sed /// 125198090Srdivacky const std::vector<LoopT *> &getSubLoops() const { return SubLoops; } 126245431Sdim std::vector<LoopT *> &getSubLoopsVector() { return SubLoops; } 127198090Srdivacky typedef typename std::vector<LoopT *>::const_iterator iterator; 128245431Sdim typedef typename std::vector<LoopT *>::const_reverse_iterator 129245431Sdim reverse_iterator; 130193323Sed iterator begin() const { return SubLoops.begin(); } 131193323Sed iterator end() const { return SubLoops.end(); } 132245431Sdim reverse_iterator rbegin() const { return SubLoops.rbegin(); } 133245431Sdim reverse_iterator rend() const { return SubLoops.rend(); } 134193323Sed bool empty() const { return SubLoops.empty(); } 135193323Sed 136193323Sed /// getBlocks - Get a list of the basic blocks which make up this loop. 137193323Sed /// 138193323Sed const std::vector<BlockT*> &getBlocks() const { return Blocks; } 139193323Sed typedef typename std::vector<BlockT*>::const_iterator block_iterator; 140193323Sed block_iterator block_begin() const { return Blocks.begin(); } 141193323Sed block_iterator block_end() const { return Blocks.end(); } 142193323Sed 143226890Sdim /// getNumBlocks - Get the number of blocks in this loop in constant time. 144226890Sdim unsigned getNumBlocks() const { 145226890Sdim return Blocks.size(); 146226890Sdim } 147226890Sdim 148199481Srdivacky /// isLoopExiting - True if terminator in the block can branch to another 149199481Srdivacky /// block that is outside of the current loop. 150193323Sed /// 151198892Srdivacky bool isLoopExiting(const BlockT *BB) const { 152252723Sdim typedef GraphTraits<const BlockT*> BlockTraits; 153193323Sed for (typename BlockTraits::ChildIteratorType SI = 154252723Sdim BlockTraits::child_begin(BB), 155252723Sdim SE = BlockTraits::child_end(BB); SI != SE; ++SI) { 156193323Sed if (!contains(*SI)) 157193323Sed return true; 158193323Sed } 159193323Sed return false; 160193323Sed } 161193323Sed 162193323Sed /// getNumBackEdges - Calculate the number of back edges to the loop header 163193323Sed /// 164193323Sed unsigned getNumBackEdges() const { 165193323Sed unsigned NumBackEdges = 0; 166193323Sed BlockT *H = getHeader(); 167193323Sed 168193323Sed typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits; 169193323Sed for (typename InvBlockTraits::ChildIteratorType I = 170252723Sdim InvBlockTraits::child_begin(H), 171252723Sdim E = InvBlockTraits::child_end(H); I != E; ++I) 172193323Sed if (contains(*I)) 173193323Sed ++NumBackEdges; 174193323Sed 175193323Sed return NumBackEdges; 176193323Sed } 177193323Sed 178193323Sed //===--------------------------------------------------------------------===// 179193323Sed // APIs for simple analysis of the loop. 180193323Sed // 181193323Sed // Note that all of these methods can fail on general loops (ie, there may not 182193323Sed // be a preheader, etc). For best success, the loop simplification and 183193323Sed // induction variable canonicalization pass should be used to normalize loops 184193323Sed // for easy analysis. These methods assume canonical loops. 185193323Sed 186193323Sed /// getExitingBlocks - Return all blocks inside the loop that have successors 187193323Sed /// outside of the loop. These are the blocks _inside of the current loop_ 188193323Sed /// which branch out. The returned list is always unique. 189193323Sed /// 190245431Sdim void getExitingBlocks(SmallVectorImpl<BlockT *> &ExitingBlocks) const; 191193323Sed 192193323Sed /// getExitingBlock - If getExitingBlocks would return exactly one block, 193193323Sed /// return that block. Otherwise return null. 194245431Sdim BlockT *getExitingBlock() const; 195193323Sed 196193323Sed /// getExitBlocks - Return all of the successor blocks of this loop. These 197193323Sed /// are the blocks _outside of the current loop_ which are branched to. 198193323Sed /// 199245431Sdim void getExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const; 200193323Sed 201193323Sed /// getExitBlock - If getExitBlocks would return exactly one block, 202193323Sed /// return that block. Otherwise return null. 203245431Sdim BlockT *getExitBlock() const; 204193323Sed 205212904Sdim /// Edge type. 206245431Sdim typedef std::pair<const BlockT*, const BlockT*> Edge; 207212904Sdim 208198090Srdivacky /// getExitEdges - Return all pairs of (_inside_block_,_outside_block_). 209245431Sdim void getExitEdges(SmallVectorImpl<Edge> &ExitEdges) const; 210193323Sed 211193323Sed /// getLoopPreheader - If there is a preheader for this loop, return it. A 212193323Sed /// loop has a preheader if there is only one edge to the header of the loop 213193323Sed /// from outside of the loop. If this is the case, the block branching to the 214193323Sed /// header of the loop is the preheader node. 215193323Sed /// 216193323Sed /// This method returns null if there is no preheader for the loop. 217193323Sed /// 218245431Sdim BlockT *getLoopPreheader() const; 219210299Sed 220210299Sed /// getLoopPredecessor - If the given loop's header has exactly one unique 221210299Sed /// predecessor outside the loop, return it. Otherwise return null. 222210299Sed /// This is less strict that the loop "preheader" concept, which requires 223210299Sed /// the predecessor to have exactly one successor. 224210299Sed /// 225245431Sdim BlockT *getLoopPredecessor() const; 226193323Sed 227193323Sed /// getLoopLatch - If there is a single latch block for this loop, return it. 228193323Sed /// A latch block is a block that contains a branch back to the header. 229245431Sdim BlockT *getLoopLatch() const; 230193323Sed 231193323Sed //===--------------------------------------------------------------------===// 232193323Sed // APIs for updating loop information after changing the CFG 233193323Sed // 234193323Sed 235193323Sed /// addBasicBlockToLoop - This method is used by other analyses to update loop 236193323Sed /// information. NewBB is set to be a new member of the current loop. 237193323Sed /// Because of this, it is added as a member of all parent loops, and is added 238193323Sed /// to the specified LoopInfo object as being in the current basic block. It 239193323Sed /// is not valid to replace the loop header with this method. 240193323Sed /// 241198090Srdivacky void addBasicBlockToLoop(BlockT *NewBB, LoopInfoBase<BlockT, LoopT> &LI); 242193323Sed 243193323Sed /// replaceChildLoopWith - This is used when splitting loops up. It replaces 244193323Sed /// the OldChild entry in our children list with NewChild, and updates the 245193323Sed /// parent pointer of OldChild to be null and the NewChild to be this loop. 246193323Sed /// This updates the loop depth of the new child. 247245431Sdim void replaceChildLoopWith(LoopT *OldChild, LoopT *NewChild); 248193323Sed 249193323Sed /// addChildLoop - Add the specified loop to be a child of this loop. This 250193323Sed /// updates the loop depth of the new child. 251193323Sed /// 252198090Srdivacky void addChildLoop(LoopT *NewChild) { 253193323Sed assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!"); 254198090Srdivacky NewChild->ParentLoop = static_cast<LoopT *>(this); 255193323Sed SubLoops.push_back(NewChild); 256193323Sed } 257193323Sed 258193323Sed /// removeChildLoop - This removes the specified child from being a subloop of 259193323Sed /// this loop. The loop is not deleted, as it will presumably be inserted 260193323Sed /// into another loop. 261198090Srdivacky LoopT *removeChildLoop(iterator I) { 262193323Sed assert(I != SubLoops.end() && "Cannot remove end iterator!"); 263198090Srdivacky LoopT *Child = *I; 264193323Sed assert(Child->ParentLoop == this && "Child is not a child of this loop!"); 265193323Sed SubLoops.erase(SubLoops.begin()+(I-begin())); 266193323Sed Child->ParentLoop = 0; 267193323Sed return Child; 268193323Sed } 269193323Sed 270193323Sed /// addBlockEntry - This adds a basic block directly to the basic block list. 271193323Sed /// This should only be used by transformations that create new loops. Other 272193323Sed /// transformations should use addBasicBlockToLoop. 273193323Sed void addBlockEntry(BlockT *BB) { 274193323Sed Blocks.push_back(BB); 275263509Sdim DenseBlockSet.insert(BB); 276193323Sed } 277193323Sed 278263509Sdim /// reverseBlocks - interface to reverse Blocks[from, end of loop] in this loop 279263509Sdim void reverseBlock(unsigned from) { 280263509Sdim std::reverse(Blocks.begin() + from, Blocks.end()); 281263509Sdim } 282263509Sdim 283263509Sdim /// reserveBlocks- interface to do reserve() for Blocks 284263509Sdim void reserveBlocks(unsigned size) { 285263509Sdim Blocks.reserve(size); 286263509Sdim } 287263509Sdim 288193323Sed /// moveToHeader - This method is used to move BB (which must be part of this 289193323Sed /// loop) to be the loop header of the loop (the block that dominates all 290193323Sed /// others). 291193323Sed void moveToHeader(BlockT *BB) { 292193323Sed if (Blocks[0] == BB) return; 293193323Sed for (unsigned i = 0; ; ++i) { 294193323Sed assert(i != Blocks.size() && "Loop does not contain BB!"); 295193323Sed if (Blocks[i] == BB) { 296193323Sed Blocks[i] = Blocks[0]; 297193323Sed Blocks[0] = BB; 298193323Sed return; 299193323Sed } 300193323Sed } 301193323Sed } 302193323Sed 303193323Sed /// removeBlockFromLoop - This removes the specified basic block from the 304193323Sed /// current loop, updating the Blocks as appropriate. This does not update 305193323Sed /// the mapping in the LoopInfo class. 306193323Sed void removeBlockFromLoop(BlockT *BB) { 307193323Sed RemoveFromVector(Blocks, BB); 308263509Sdim DenseBlockSet.erase(BB); 309193323Sed } 310193323Sed 311193323Sed /// verifyLoop - Verify loop structure 312245431Sdim void verifyLoop() const; 313198090Srdivacky 314198090Srdivacky /// verifyLoop - Verify loop structure of this loop and all nested loops. 315245431Sdim void verifyLoopNest(DenseSet<const LoopT*> *Loops) const; 316198090Srdivacky 317245431Sdim void print(raw_ostream &OS, unsigned Depth = 0) const; 318193323Sed 319198090Srdivackyprotected: 320198090Srdivacky friend class LoopInfoBase<BlockT, LoopT>; 321193323Sed explicit LoopBase(BlockT *BB) : ParentLoop(0) { 322193323Sed Blocks.push_back(BB); 323263509Sdim DenseBlockSet.insert(BB); 324193323Sed } 325193323Sed}; 326193323Sed 327212904Sdimtemplate<class BlockT, class LoopT> 328212904Sdimraw_ostream& operator<<(raw_ostream &OS, const LoopBase<BlockT, LoopT> &Loop) { 329212904Sdim Loop.print(OS); 330212904Sdim return OS; 331212904Sdim} 332212904Sdim 333245431Sdim// Implementation in LoopInfoImpl.h 334245431Sdim#ifdef __GNUC__ 335245431Sdim__extension__ extern template class LoopBase<BasicBlock, Loop>; 336245431Sdim#endif 337245431Sdim 338198090Srdivackyclass Loop : public LoopBase<BasicBlock, Loop> { 339198090Srdivackypublic: 340198090Srdivacky Loop() {} 341193323Sed 342198090Srdivacky /// isLoopInvariant - Return true if the specified value is loop invariant 343198090Srdivacky /// 344198090Srdivacky bool isLoopInvariant(Value *V) const; 345198090Srdivacky 346218893Sdim /// hasLoopInvariantOperands - Return true if all the operands of the 347226890Sdim /// specified instruction are loop invariant. 348218893Sdim bool hasLoopInvariantOperands(Instruction *I) const; 349198090Srdivacky 350198090Srdivacky /// makeLoopInvariant - If the given value is an instruction inside of the 351198090Srdivacky /// loop and it can be hoisted, do so to make it trivially loop-invariant. 352198090Srdivacky /// Return true if the value after any hoisting is loop invariant. This 353198090Srdivacky /// function can be used as a slightly more aggressive replacement for 354198090Srdivacky /// isLoopInvariant. 355198090Srdivacky /// 356198090Srdivacky /// If InsertPt is specified, it is the point to hoist instructions to. 357198090Srdivacky /// If null, the terminator of the loop preheader is used. 358198090Srdivacky /// 359198090Srdivacky bool makeLoopInvariant(Value *V, bool &Changed, 360198090Srdivacky Instruction *InsertPt = 0) const; 361198090Srdivacky 362198090Srdivacky /// makeLoopInvariant - If the given instruction is inside of the 363198090Srdivacky /// loop and it can be hoisted, do so to make it trivially loop-invariant. 364198090Srdivacky /// Return true if the instruction after any hoisting is loop invariant. This 365198090Srdivacky /// function can be used as a slightly more aggressive replacement for 366198090Srdivacky /// isLoopInvariant. 367198090Srdivacky /// 368198090Srdivacky /// If InsertPt is specified, it is the point to hoist instructions to. 369198090Srdivacky /// If null, the terminator of the loop preheader is used. 370198090Srdivacky /// 371198090Srdivacky bool makeLoopInvariant(Instruction *I, bool &Changed, 372198090Srdivacky Instruction *InsertPt = 0) const; 373198090Srdivacky 374198090Srdivacky /// getCanonicalInductionVariable - Check to see if the loop has a canonical 375198090Srdivacky /// induction variable: an integer recurrence that starts at 0 and increments 376198090Srdivacky /// by one each time through the loop. If so, return the phi node that 377198090Srdivacky /// corresponds to it. 378198090Srdivacky /// 379198090Srdivacky /// The IndVarSimplify pass transforms loops to have a canonical induction 380198090Srdivacky /// variable. 381198090Srdivacky /// 382198090Srdivacky PHINode *getCanonicalInductionVariable() const; 383198090Srdivacky 384198090Srdivacky /// isLCSSAForm - Return true if the Loop is in LCSSA form 385205218Srdivacky bool isLCSSAForm(DominatorTree &DT) const; 386198090Srdivacky 387198090Srdivacky /// isLoopSimplifyForm - Return true if the Loop is in the form that 388198090Srdivacky /// the LoopSimplify form transforms loops to, which is sometimes called 389198090Srdivacky /// normal form. 390198090Srdivacky bool isLoopSimplifyForm() const; 391198090Srdivacky 392235633Sdim /// isSafeToClone - Return true if the loop body is safe to clone in practice. 393235633Sdim bool isSafeToClone() const; 394235633Sdim 395252723Sdim /// Returns true if the loop is annotated parallel. 396252723Sdim /// 397252723Sdim /// A parallel loop can be assumed to not contain any dependencies between 398252723Sdim /// iterations by the compiler. That is, any loop-carried dependency checking 399252723Sdim /// can be skipped completely when parallelizing the loop on the target 400252723Sdim /// machine. Thus, if the parallel loop information originates from the 401252723Sdim /// programmer, e.g. via the OpenMP parallel for pragma, it is the 402252723Sdim /// programmer's responsibility to ensure there are no loop-carried 403252723Sdim /// dependencies. The final execution order of the instructions across 404252723Sdim /// iterations is not guaranteed, thus, the end result might or might not 405252723Sdim /// implement actual concurrent execution of instructions across multiple 406252723Sdim /// iterations. 407252723Sdim bool isAnnotatedParallel() const; 408252723Sdim 409263509Sdim /// Return the llvm.loop loop id metadata node for this loop if it is present. 410263509Sdim /// 411263509Sdim /// If this loop contains the same llvm.loop metadata on each branch to the 412263509Sdim /// header then the node is returned. If any latch instruction does not 413263509Sdim /// contain llvm.loop or or if multiple latches contain different nodes then 414263509Sdim /// 0 is returned. 415263509Sdim MDNode *getLoopID() const; 416263509Sdim /// Set the llvm.loop loop id metadata for this loop. 417263509Sdim /// 418263509Sdim /// The LoopID metadata node will be added to each terminator instruction in 419263509Sdim /// the loop that branches to the loop header. 420263509Sdim /// 421263509Sdim /// The LoopID metadata node should have one or more operands and the first 422263509Sdim /// operand should should be the node itself. 423263509Sdim void setLoopID(MDNode *LoopID) const; 424263509Sdim 425199481Srdivacky /// hasDedicatedExits - Return true if no exit block for the loop 426199481Srdivacky /// has a predecessor that is outside the loop. 427199481Srdivacky bool hasDedicatedExits() const; 428199481Srdivacky 429226890Sdim /// getUniqueExitBlocks - Return all unique successor blocks of this loop. 430198090Srdivacky /// These are the blocks _outside of the current loop_ which are branched to. 431200581Srdivacky /// This assumes that loop exits are in canonical form. 432198090Srdivacky /// 433198090Srdivacky void getUniqueExitBlocks(SmallVectorImpl<BasicBlock *> &ExitBlocks) const; 434198090Srdivacky 435198090Srdivacky /// getUniqueExitBlock - If getUniqueExitBlocks would return exactly one 436198090Srdivacky /// block, return that block. Otherwise return null. 437198090Srdivacky BasicBlock *getUniqueExitBlock() const; 438198090Srdivacky 439202375Srdivacky void dump() const; 440226890Sdim 441198090Srdivackyprivate: 442198090Srdivacky friend class LoopInfoBase<BasicBlock, Loop>; 443198090Srdivacky explicit Loop(BasicBlock *BB) : LoopBase<BasicBlock, Loop>(BB) {} 444198090Srdivacky}; 445198090Srdivacky 446193323Sed//===----------------------------------------------------------------------===// 447193323Sed/// LoopInfo - This class builds and contains all of the top level loop 448193323Sed/// structures in the specified function. 449193323Sed/// 450193323Sed 451198090Srdivackytemplate<class BlockT, class LoopT> 452193323Sedclass LoopInfoBase { 453193323Sed // BBMap - Mapping of basic blocks to the inner most loop they occur in 454218893Sdim DenseMap<BlockT *, LoopT *> BBMap; 455198090Srdivacky std::vector<LoopT *> TopLevelLoops; 456198090Srdivacky friend class LoopBase<BlockT, LoopT>; 457226890Sdim friend class LoopInfo; 458195340Sed 459245431Sdim void operator=(const LoopInfoBase &) LLVM_DELETED_FUNCTION; 460245431Sdim LoopInfoBase(const LoopInfo &) LLVM_DELETED_FUNCTION; 461193323Sedpublic: 462193323Sed LoopInfoBase() { } 463193323Sed ~LoopInfoBase() { releaseMemory(); } 464226890Sdim 465193323Sed void releaseMemory() { 466198090Srdivacky for (typename std::vector<LoopT *>::iterator I = 467193323Sed TopLevelLoops.begin(), E = TopLevelLoops.end(); I != E; ++I) 468193323Sed delete *I; // Delete all of the loops... 469193323Sed 470193323Sed BBMap.clear(); // Reset internal state of analysis 471193323Sed TopLevelLoops.clear(); 472193323Sed } 473226890Sdim 474193323Sed /// iterator/begin/end - The interface to the top-level loops in the current 475193323Sed /// function. 476193323Sed /// 477198090Srdivacky typedef typename std::vector<LoopT *>::const_iterator iterator; 478245431Sdim typedef typename std::vector<LoopT *>::const_reverse_iterator 479245431Sdim reverse_iterator; 480193323Sed iterator begin() const { return TopLevelLoops.begin(); } 481193323Sed iterator end() const { return TopLevelLoops.end(); } 482245431Sdim reverse_iterator rbegin() const { return TopLevelLoops.rbegin(); } 483245431Sdim reverse_iterator rend() const { return TopLevelLoops.rend(); } 484193323Sed bool empty() const { return TopLevelLoops.empty(); } 485226890Sdim 486193323Sed /// getLoopFor - Return the inner most loop that BB lives in. If a basic 487193323Sed /// block is in no loop (for example the entry node), null is returned. 488193323Sed /// 489198090Srdivacky LoopT *getLoopFor(const BlockT *BB) const { 490235633Sdim return BBMap.lookup(const_cast<BlockT*>(BB)); 491193323Sed } 492226890Sdim 493193323Sed /// operator[] - same as getLoopFor... 494193323Sed /// 495198090Srdivacky const LoopT *operator[](const BlockT *BB) const { 496193323Sed return getLoopFor(BB); 497193323Sed } 498226890Sdim 499193323Sed /// getLoopDepth - Return the loop nesting level of the specified block. A 500193323Sed /// depth of 0 means the block is not inside any loop. 501193323Sed /// 502193323Sed unsigned getLoopDepth(const BlockT *BB) const { 503198090Srdivacky const LoopT *L = getLoopFor(BB); 504193323Sed return L ? L->getLoopDepth() : 0; 505193323Sed } 506193323Sed 507193323Sed // isLoopHeader - True if the block is a loop header node 508193323Sed bool isLoopHeader(BlockT *BB) const { 509198090Srdivacky const LoopT *L = getLoopFor(BB); 510193323Sed return L && L->getHeader() == BB; 511193323Sed } 512226890Sdim 513193323Sed /// removeLoop - This removes the specified top-level loop from this loop info 514193323Sed /// object. The loop is not deleted, as it will presumably be inserted into 515193323Sed /// another loop. 516198090Srdivacky LoopT *removeLoop(iterator I) { 517193323Sed assert(I != end() && "Cannot remove end iterator!"); 518198090Srdivacky LoopT *L = *I; 519193323Sed assert(L->getParentLoop() == 0 && "Not a top-level loop!"); 520193323Sed TopLevelLoops.erase(TopLevelLoops.begin() + (I-begin())); 521193323Sed return L; 522193323Sed } 523226890Sdim 524193323Sed /// changeLoopFor - Change the top-level loop that contains BB to the 525193323Sed /// specified loop. This should be used by transformations that restructure 526193323Sed /// the loop hierarchy tree. 527198090Srdivacky void changeLoopFor(BlockT *BB, LoopT *L) { 528226890Sdim if (!L) { 529235633Sdim BBMap.erase(BB); 530226890Sdim return; 531226890Sdim } 532226890Sdim BBMap[BB] = L; 533193323Sed } 534226890Sdim 535193323Sed /// changeTopLevelLoop - Replace the specified loop in the top-level loops 536193323Sed /// list with the indicated loop. 537198090Srdivacky void changeTopLevelLoop(LoopT *OldLoop, 538198090Srdivacky LoopT *NewLoop) { 539198090Srdivacky typename std::vector<LoopT *>::iterator I = 540193323Sed std::find(TopLevelLoops.begin(), TopLevelLoops.end(), OldLoop); 541193323Sed assert(I != TopLevelLoops.end() && "Old loop not at top level!"); 542193323Sed *I = NewLoop; 543193323Sed assert(NewLoop->ParentLoop == 0 && OldLoop->ParentLoop == 0 && 544193323Sed "Loops already embedded into a subloop!"); 545193323Sed } 546226890Sdim 547193323Sed /// addTopLevelLoop - This adds the specified loop to the collection of 548193323Sed /// top-level loops. 549198090Srdivacky void addTopLevelLoop(LoopT *New) { 550193323Sed assert(New->getParentLoop() == 0 && "Loop already in subloop!"); 551193323Sed TopLevelLoops.push_back(New); 552193323Sed } 553226890Sdim 554193323Sed /// removeBlock - This method completely removes BB from all data structures, 555193323Sed /// including all of the Loop objects it is nested in and our mapping from 556193323Sed /// BasicBlocks to loops. 557193323Sed void removeBlock(BlockT *BB) { 558218893Sdim typename DenseMap<BlockT *, LoopT *>::iterator I = BBMap.find(BB); 559193323Sed if (I != BBMap.end()) { 560198090Srdivacky for (LoopT *L = I->second; L; L = L->getParentLoop()) 561193323Sed L->removeBlockFromLoop(BB); 562193323Sed 563193323Sed BBMap.erase(I); 564193323Sed } 565193323Sed } 566226890Sdim 567193323Sed // Internals 568226890Sdim 569198090Srdivacky static bool isNotAlreadyContainedIn(const LoopT *SubLoop, 570198090Srdivacky const LoopT *ParentLoop) { 571193323Sed if (SubLoop == 0) return true; 572193323Sed if (SubLoop == ParentLoop) return false; 573193323Sed return isNotAlreadyContainedIn(SubLoop->getParentLoop(), ParentLoop); 574193323Sed } 575226890Sdim 576245431Sdim /// Create the loop forest using a stable algorithm. 577245431Sdim void Analyze(DominatorTreeBase<BlockT> &DomTree); 578193323Sed 579193323Sed // Debugging 580226890Sdim 581245431Sdim void print(raw_ostream &OS) const; 582193323Sed}; 583193323Sed 584245431Sdim// Implementation in LoopInfoImpl.h 585245431Sdim#ifdef __GNUC__ 586245431Sdim__extension__ extern template class LoopInfoBase<BasicBlock, Loop>; 587245431Sdim#endif 588245431Sdim 589193323Sedclass LoopInfo : public FunctionPass { 590198090Srdivacky LoopInfoBase<BasicBlock, Loop> LI; 591198090Srdivacky friend class LoopBase<BasicBlock, Loop>; 592195340Sed 593245431Sdim void operator=(const LoopInfo &) LLVM_DELETED_FUNCTION; 594245431Sdim LoopInfo(const LoopInfo &) LLVM_DELETED_FUNCTION; 595193323Sedpublic: 596193323Sed static char ID; // Pass identification, replacement for typeid 597193323Sed 598218893Sdim LoopInfo() : FunctionPass(ID) { 599218893Sdim initializeLoopInfoPass(*PassRegistry::getPassRegistry()); 600218893Sdim } 601193323Sed 602198090Srdivacky LoopInfoBase<BasicBlock, Loop>& getBase() { return LI; } 603193323Sed 604193323Sed /// iterator/begin/end - The interface to the top-level loops in the current 605193323Sed /// function. 606193323Sed /// 607198090Srdivacky typedef LoopInfoBase<BasicBlock, Loop>::iterator iterator; 608245431Sdim typedef LoopInfoBase<BasicBlock, Loop>::reverse_iterator reverse_iterator; 609195340Sed inline iterator begin() const { return LI.begin(); } 610195340Sed inline iterator end() const { return LI.end(); } 611245431Sdim inline reverse_iterator rbegin() const { return LI.rbegin(); } 612245431Sdim inline reverse_iterator rend() const { return LI.rend(); } 613195340Sed bool empty() const { return LI.empty(); } 614193323Sed 615193323Sed /// getLoopFor - Return the inner most loop that BB lives in. If a basic 616193323Sed /// block is in no loop (for example the entry node), null is returned. 617193323Sed /// 618193323Sed inline Loop *getLoopFor(const BasicBlock *BB) const { 619195340Sed return LI.getLoopFor(BB); 620193323Sed } 621193323Sed 622193323Sed /// operator[] - same as getLoopFor... 623193323Sed /// 624193323Sed inline const Loop *operator[](const BasicBlock *BB) const { 625195340Sed return LI.getLoopFor(BB); 626193323Sed } 627193323Sed 628193323Sed /// getLoopDepth - Return the loop nesting level of the specified block. A 629193323Sed /// depth of 0 means the block is not inside any loop. 630193323Sed /// 631193323Sed inline unsigned getLoopDepth(const BasicBlock *BB) const { 632195340Sed return LI.getLoopDepth(BB); 633193323Sed } 634193323Sed 635193323Sed // isLoopHeader - True if the block is a loop header node 636193323Sed inline bool isLoopHeader(BasicBlock *BB) const { 637195340Sed return LI.isLoopHeader(BB); 638193323Sed } 639193323Sed 640193323Sed /// runOnFunction - Calculate the natural loop information. 641193323Sed /// 642193323Sed virtual bool runOnFunction(Function &F); 643193323Sed 644198090Srdivacky virtual void verifyAnalysis() const; 645198090Srdivacky 646195340Sed virtual void releaseMemory() { LI.releaseMemory(); } 647193323Sed 648198090Srdivacky virtual void print(raw_ostream &O, const Module* M = 0) const; 649226890Sdim 650193323Sed virtual void getAnalysisUsage(AnalysisUsage &AU) const; 651193323Sed 652193323Sed /// removeLoop - This removes the specified top-level loop from this loop info 653193323Sed /// object. The loop is not deleted, as it will presumably be inserted into 654193323Sed /// another loop. 655195340Sed inline Loop *removeLoop(iterator I) { return LI.removeLoop(I); } 656193323Sed 657193323Sed /// changeLoopFor - Change the top-level loop that contains BB to the 658193323Sed /// specified loop. This should be used by transformations that restructure 659193323Sed /// the loop hierarchy tree. 660193323Sed inline void changeLoopFor(BasicBlock *BB, Loop *L) { 661195340Sed LI.changeLoopFor(BB, L); 662193323Sed } 663193323Sed 664193323Sed /// changeTopLevelLoop - Replace the specified loop in the top-level loops 665193323Sed /// list with the indicated loop. 666193323Sed inline void changeTopLevelLoop(Loop *OldLoop, Loop *NewLoop) { 667195340Sed LI.changeTopLevelLoop(OldLoop, NewLoop); 668193323Sed } 669193323Sed 670193323Sed /// addTopLevelLoop - This adds the specified loop to the collection of 671193323Sed /// top-level loops. 672193323Sed inline void addTopLevelLoop(Loop *New) { 673195340Sed LI.addTopLevelLoop(New); 674193323Sed } 675193323Sed 676193323Sed /// removeBlock - This method completely removes BB from all data structures, 677193323Sed /// including all of the Loop objects it is nested in and our mapping from 678193323Sed /// BasicBlocks to loops. 679193323Sed void removeBlock(BasicBlock *BB) { 680195340Sed LI.removeBlock(BB); 681193323Sed } 682218893Sdim 683226890Sdim /// updateUnloop - Update LoopInfo after removing the last backedge from a 684226890Sdim /// loop--now the "unloop". This updates the loop forest and parent loops for 685226890Sdim /// each block so that Unloop is no longer referenced, but the caller must 686226890Sdim /// actually delete the Unloop object. 687226890Sdim void updateUnloop(Loop *Unloop); 688226890Sdim 689218893Sdim /// replacementPreservesLCSSAForm - Returns true if replacing From with To 690218893Sdim /// everywhere is guaranteed to preserve LCSSA form. 691218893Sdim bool replacementPreservesLCSSAForm(Instruction *From, Value *To) { 692218893Sdim // Preserving LCSSA form is only problematic if the replacing value is an 693218893Sdim // instruction. 694218893Sdim Instruction *I = dyn_cast<Instruction>(To); 695218893Sdim if (!I) return true; 696218893Sdim // If both instructions are defined in the same basic block then replacement 697218893Sdim // cannot break LCSSA form. 698218893Sdim if (I->getParent() == From->getParent()) 699218893Sdim return true; 700218893Sdim // If the instruction is not defined in a loop then it can safely replace 701218893Sdim // anything. 702218893Sdim Loop *ToLoop = getLoopFor(I->getParent()); 703218893Sdim if (!ToLoop) return true; 704218893Sdim // If the replacing instruction is defined in the same loop as the original 705218893Sdim // instruction, or in a loop that contains it as an inner loop, then using 706218893Sdim // it as a replacement will not break LCSSA form. 707218893Sdim return ToLoop->contains(getLoopFor(From->getParent())); 708218893Sdim } 709193323Sed}; 710193323Sed 711193323Sed 712193323Sed// Allow clients to walk the list of nested loops... 713193323Sedtemplate <> struct GraphTraits<const Loop*> { 714193323Sed typedef const Loop NodeType; 715195340Sed typedef LoopInfo::iterator ChildIteratorType; 716193323Sed 717193323Sed static NodeType *getEntryNode(const Loop *L) { return L; } 718193323Sed static inline ChildIteratorType child_begin(NodeType *N) { 719193323Sed return N->begin(); 720193323Sed } 721193323Sed static inline ChildIteratorType child_end(NodeType *N) { 722193323Sed return N->end(); 723193323Sed } 724193323Sed}; 725193323Sed 726193323Sedtemplate <> struct GraphTraits<Loop*> { 727193323Sed typedef Loop NodeType; 728195340Sed typedef LoopInfo::iterator ChildIteratorType; 729193323Sed 730193323Sed static NodeType *getEntryNode(Loop *L) { return L; } 731193323Sed static inline ChildIteratorType child_begin(NodeType *N) { 732193323Sed return N->begin(); 733193323Sed } 734193323Sed static inline ChildIteratorType child_end(NodeType *N) { 735193323Sed return N->end(); 736193323Sed } 737193323Sed}; 738193323Sed 739193323Sed} // End llvm namespace 740193323Sed 741193323Sed#endif 742