ScalarEvolution.h revision c050fd94c29e31414591e3a18aa20049e6b3a84f
1//===- llvm/Analysis/ScalarEvolution.h - Scalar Evolution -------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// The ScalarEvolution class is an LLVM pass which can be used to analyze and 11// catagorize scalar expressions in loops. It specializes in recognizing 12// general induction variables, representing them with the abstract and opaque 13// SCEV class. Given this analysis, trip counts of loops and other important 14// properties can be obtained. 15// 16// This analysis is primarily useful for induction variable substitution and 17// strength reduction. 18// 19//===----------------------------------------------------------------------===// 20 21#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_H 22#define LLVM_ANALYSIS_SCALAREVOLUTION_H 23 24#include "llvm/Pass.h" 25#include "llvm/Analysis/LoopInfo.h" 26#include "llvm/Support/DataTypes.h" 27#include "llvm/Support/ValueHandle.h" 28#include "llvm/Support/Allocator.h" 29#include "llvm/ADT/FoldingSet.h" 30#include "llvm/ADT/DenseMap.h" 31#include <iosfwd> 32 33namespace llvm { 34 class APInt; 35 class ConstantInt; 36 class Type; 37 class ScalarEvolution; 38 class TargetData; 39 class LLVMContext; 40 41 /// SCEV - This class represents an analyzed expression in the program. These 42 /// are opaque objects that the client is not allowed to do much with 43 /// directly. 44 /// 45 class SCEV : public FastFoldingSetNode { 46 const unsigned SCEVType; // The SCEV baseclass this node corresponds to 47 48 SCEV(const SCEV &); // DO NOT IMPLEMENT 49 void operator=(const SCEV &); // DO NOT IMPLEMENT 50 protected: 51 virtual ~SCEV(); 52 public: 53 explicit SCEV(const FoldingSetNodeID &ID, unsigned SCEVTy) : 54 FastFoldingSetNode(ID), SCEVType(SCEVTy) {} 55 56 unsigned getSCEVType() const { return SCEVType; } 57 58 /// isLoopInvariant - Return true if the value of this SCEV is unchanging in 59 /// the specified loop. 60 virtual bool isLoopInvariant(const Loop *L) const = 0; 61 62 /// hasComputableLoopEvolution - Return true if this SCEV changes value in a 63 /// known way in the specified loop. This property being true implies that 64 /// the value is variant in the loop AND that we can emit an expression to 65 /// compute the value of the expression at any particular loop iteration. 66 virtual bool hasComputableLoopEvolution(const Loop *L) const = 0; 67 68 /// getType - Return the LLVM type of this SCEV expression. 69 /// 70 virtual const Type *getType() const = 0; 71 72 /// isZero - Return true if the expression is a constant zero. 73 /// 74 bool isZero() const; 75 76 /// isOne - Return true if the expression is a constant one. 77 /// 78 bool isOne() const; 79 80 /// isAllOnesValue - Return true if the expression is a constant 81 /// all-ones value. 82 /// 83 bool isAllOnesValue() const; 84 85 /// replaceSymbolicValuesWithConcrete - If this SCEV internally references 86 /// the symbolic value "Sym", construct and return a new SCEV that produces 87 /// the same value, but which uses the concrete value Conc instead of the 88 /// symbolic value. If this SCEV does not use the symbolic value, it 89 /// returns itself. 90 virtual const SCEV * 91 replaceSymbolicValuesWithConcrete(const SCEV *Sym, 92 const SCEV *Conc, 93 ScalarEvolution &SE) const = 0; 94 95 /// dominates - Return true if elements that makes up this SCEV dominates 96 /// the specified basic block. 97 virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const = 0; 98 99 /// print - Print out the internal representation of this scalar to the 100 /// specified stream. This should really only be used for debugging 101 /// purposes. 102 virtual void print(raw_ostream &OS) const = 0; 103 void print(std::ostream &OS) const; 104 void print(std::ostream *OS) const { if (OS) print(*OS); } 105 106 /// dump - This method is used for debugging. 107 /// 108 void dump() const; 109 }; 110 111 inline raw_ostream &operator<<(raw_ostream &OS, const SCEV &S) { 112 S.print(OS); 113 return OS; 114 } 115 116 inline std::ostream &operator<<(std::ostream &OS, const SCEV &S) { 117 S.print(OS); 118 return OS; 119 } 120 121 /// SCEVCouldNotCompute - An object of this class is returned by queries that 122 /// could not be answered. For example, if you ask for the number of 123 /// iterations of a linked-list traversal loop, you will get one of these. 124 /// None of the standard SCEV operations are valid on this class, it is just a 125 /// marker. 126 struct SCEVCouldNotCompute : public SCEV { 127 SCEVCouldNotCompute(); 128 129 // None of these methods are valid for this object. 130 virtual bool isLoopInvariant(const Loop *L) const; 131 virtual const Type *getType() const; 132 virtual bool hasComputableLoopEvolution(const Loop *L) const; 133 virtual void print(raw_ostream &OS) const; 134 virtual const SCEV * 135 replaceSymbolicValuesWithConcrete(const SCEV *Sym, 136 const SCEV *Conc, 137 ScalarEvolution &SE) const; 138 139 virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const { 140 return true; 141 } 142 143 /// Methods for support type inquiry through isa, cast, and dyn_cast: 144 static inline bool classof(const SCEVCouldNotCompute *S) { return true; } 145 static bool classof(const SCEV *S); 146 }; 147 148 /// ScalarEvolution - This class is the main scalar evolution driver. Because 149 /// client code (intentionally) can't do much with the SCEV objects directly, 150 /// they must ask this class for services. 151 /// 152 class ScalarEvolution : public FunctionPass { 153 /// SCEVCallbackVH - A CallbackVH to arrange for ScalarEvolution to be 154 /// notified whenever a Value is deleted. 155 class SCEVCallbackVH : public CallbackVH { 156 ScalarEvolution *SE; 157 virtual void deleted(); 158 virtual void allUsesReplacedWith(Value *New); 159 public: 160 SCEVCallbackVH(Value *V, ScalarEvolution *SE = 0); 161 }; 162 163 friend class SCEVCallbackVH; 164 friend struct SCEVExpander; 165 166 /// F - The function we are analyzing. 167 /// 168 Function *F; 169 170 /// LI - The loop information for the function we are currently analyzing. 171 /// 172 LoopInfo *LI; 173 174 /// TD - The target data information for the target we are targetting. 175 /// 176 TargetData *TD; 177 178 /// CouldNotCompute - This SCEV is used to represent unknown trip 179 /// counts and things. 180 SCEVCouldNotCompute CouldNotCompute; 181 182 /// Scalars - This is a cache of the scalars we have analyzed so far. 183 /// 184 std::map<SCEVCallbackVH, const SCEV *> Scalars; 185 186 /// BackedgeTakenInfo - Information about the backedge-taken count 187 /// of a loop. This currently inclues an exact count and a maximum count. 188 /// 189 struct BackedgeTakenInfo { 190 /// Exact - An expression indicating the exact backedge-taken count of 191 /// the loop if it is known, or a SCEVCouldNotCompute otherwise. 192 const SCEV *Exact; 193 194 /// Max - An expression indicating the least maximum backedge-taken 195 /// count of the loop that is known, or a SCEVCouldNotCompute. 196 const SCEV *Max; 197 198 /*implicit*/ BackedgeTakenInfo(const SCEV *exact) : 199 Exact(exact), Max(exact) {} 200 201 BackedgeTakenInfo(const SCEV *exact, const SCEV *max) : 202 Exact(exact), Max(max) {} 203 204 /// hasAnyInfo - Test whether this BackedgeTakenInfo contains any 205 /// computed information, or whether it's all SCEVCouldNotCompute 206 /// values. 207 bool hasAnyInfo() const { 208 return !isa<SCEVCouldNotCompute>(Exact) || 209 !isa<SCEVCouldNotCompute>(Max); 210 } 211 }; 212 213 /// BackedgeTakenCounts - Cache the backedge-taken count of the loops for 214 /// this function as they are computed. 215 std::map<const Loop*, BackedgeTakenInfo> BackedgeTakenCounts; 216 217 /// ConstantEvolutionLoopExitValue - This map contains entries for all of 218 /// the PHI instructions that we attempt to compute constant evolutions for. 219 /// This allows us to avoid potentially expensive recomputation of these 220 /// properties. An instruction maps to null if we are unable to compute its 221 /// exit value. 222 std::map<PHINode*, Constant*> ConstantEvolutionLoopExitValue; 223 224 /// ValuesAtScopes - This map contains entries for all the instructions 225 /// that we attempt to compute getSCEVAtScope information for without 226 /// using SCEV techniques, which can be expensive. 227 std::map<Instruction *, std::map<const Loop *, Constant *> > ValuesAtScopes; 228 229 /// createSCEV - We know that there is no SCEV for the specified value. 230 /// Analyze the expression. 231 const SCEV *createSCEV(Value *V); 232 233 /// createNodeForPHI - Provide the special handling we need to analyze PHI 234 /// SCEVs. 235 const SCEV *createNodeForPHI(PHINode *PN); 236 237 /// createNodeForGEP - Provide the special handling we need to analyze GEP 238 /// SCEVs. 239 const SCEV *createNodeForGEP(User *GEP); 240 241 /// ReplaceSymbolicValueWithConcrete - This looks up the computed SCEV value 242 /// for the specified instruction and replaces any references to the 243 /// symbolic value SymName with the specified value. This is used during 244 /// PHI resolution. 245 void ReplaceSymbolicValueWithConcrete(Instruction *I, 246 const SCEV *SymName, 247 const SCEV *NewVal); 248 249 /// getBECount - Subtract the end and start values and divide by the step, 250 /// rounding up, to get the number of times the backedge is executed. Return 251 /// CouldNotCompute if an intermediate computation overflows. 252 const SCEV *getBECount(const SCEV *Start, 253 const SCEV *End, 254 const SCEV *Step); 255 256 /// getBackedgeTakenInfo - Return the BackedgeTakenInfo for the given 257 /// loop, lazily computing new values if the loop hasn't been analyzed 258 /// yet. 259 const BackedgeTakenInfo &getBackedgeTakenInfo(const Loop *L); 260 261 /// ComputeBackedgeTakenCount - Compute the number of times the specified 262 /// loop will iterate. 263 BackedgeTakenInfo ComputeBackedgeTakenCount(const Loop *L); 264 265 /// ComputeBackedgeTakenCountFromExit - Compute the number of times the 266 /// backedge of the specified loop will execute if it exits via the 267 /// specified block. 268 BackedgeTakenInfo ComputeBackedgeTakenCountFromExit(const Loop *L, 269 BasicBlock *ExitingBlock); 270 271 /// ComputeBackedgeTakenCountFromExitCond - Compute the number of times the 272 /// backedge of the specified loop will execute if its exit condition 273 /// were a conditional branch of ExitCond, TBB, and FBB. 274 BackedgeTakenInfo 275 ComputeBackedgeTakenCountFromExitCond(const Loop *L, 276 Value *ExitCond, 277 BasicBlock *TBB, 278 BasicBlock *FBB); 279 280 /// ComputeBackedgeTakenCountFromExitCondICmp - Compute the number of 281 /// times the backedge of the specified loop will execute if its exit 282 /// condition were a conditional branch of the ICmpInst ExitCond, TBB, 283 /// and FBB. 284 BackedgeTakenInfo 285 ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L, 286 ICmpInst *ExitCond, 287 BasicBlock *TBB, 288 BasicBlock *FBB); 289 290 /// ComputeLoadConstantCompareBackedgeTakenCount - Given an exit condition 291 /// of 'icmp op load X, cst', try to see if we can compute the trip count. 292 const SCEV * 293 ComputeLoadConstantCompareBackedgeTakenCount(LoadInst *LI, 294 Constant *RHS, 295 const Loop *L, 296 ICmpInst::Predicate p); 297 298 /// ComputeBackedgeTakenCountExhaustively - If the trip is known to execute 299 /// a constant number of times (the condition evolves only from constants), 300 /// try to evaluate a few iterations of the loop until we get the exit 301 /// condition gets a value of ExitWhen (true or false). If we cannot 302 /// evaluate the trip count of the loop, return CouldNotCompute. 303 const SCEV *ComputeBackedgeTakenCountExhaustively(const Loop *L, 304 Value *Cond, 305 bool ExitWhen); 306 307 /// HowFarToZero - Return the number of times a backedge comparing the 308 /// specified value to zero will execute. If not computable, return 309 /// CouldNotCompute. 310 const SCEV *HowFarToZero(const SCEV *V, const Loop *L); 311 312 /// HowFarToNonZero - Return the number of times a backedge checking the 313 /// specified value for nonzero will execute. If not computable, return 314 /// CouldNotCompute. 315 const SCEV *HowFarToNonZero(const SCEV *V, const Loop *L); 316 317 /// HowManyLessThans - Return the number of times a backedge containing the 318 /// specified less-than comparison will execute. If not computable, return 319 /// CouldNotCompute. isSigned specifies whether the less-than is signed. 320 BackedgeTakenInfo HowManyLessThans(const SCEV *LHS, const SCEV *RHS, 321 const Loop *L, bool isSigned); 322 323 /// getLoopPredecessor - If the given loop's header has exactly one unique 324 /// predecessor outside the loop, return it. Otherwise return null. 325 BasicBlock *getLoopPredecessor(const Loop *L); 326 327 /// getPredecessorWithUniqueSuccessorForBB - Return a predecessor of BB 328 /// (which may not be an immediate predecessor) which has exactly one 329 /// successor from which BB is reachable, or null if no such block is 330 /// found. 331 BasicBlock* getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB); 332 333 /// isNecessaryCond - Test whether the given CondValue value is a condition 334 /// which is at least as strict as the one described by Pred, LHS, and RHS. 335 bool isNecessaryCond(Value *Cond, ICmpInst::Predicate Pred, 336 const SCEV *LHS, const SCEV *RHS, 337 bool Inverse); 338 339 /// getConstantEvolutionLoopExitValue - If we know that the specified Phi is 340 /// in the header of its containing loop, we know the loop executes a 341 /// constant number of times, and the PHI node is just a recurrence 342 /// involving constants, fold it. 343 Constant *getConstantEvolutionLoopExitValue(PHINode *PN, const APInt& BEs, 344 const Loop *L); 345 346 public: 347 static char ID; // Pass identification, replacement for typeid 348 ScalarEvolution(); 349 350 LLVMContext *getContext() const { return Context; } 351 352 /// isSCEVable - Test if values of the given type are analyzable within 353 /// the SCEV framework. This primarily includes integer types, and it 354 /// can optionally include pointer types if the ScalarEvolution class 355 /// has access to target-specific information. 356 bool isSCEVable(const Type *Ty) const; 357 358 /// getTypeSizeInBits - Return the size in bits of the specified type, 359 /// for which isSCEVable must return true. 360 uint64_t getTypeSizeInBits(const Type *Ty) const; 361 362 /// getEffectiveSCEVType - Return a type with the same bitwidth as 363 /// the given type and which represents how SCEV will treat the given 364 /// type, for which isSCEVable must return true. For pointer types, 365 /// this is the pointer-sized integer type. 366 const Type *getEffectiveSCEVType(const Type *Ty) const; 367 368 /// getSCEV - Return a SCEV expression handle for the full generality of the 369 /// specified expression. 370 const SCEV *getSCEV(Value *V); 371 372 const SCEV *getConstant(ConstantInt *V); 373 const SCEV *getConstant(const APInt& Val); 374 const SCEV *getConstant(const Type *Ty, uint64_t V, bool isSigned = false); 375 const SCEV *getTruncateExpr(const SCEV *Op, const Type *Ty); 376 const SCEV *getZeroExtendExpr(const SCEV *Op, const Type *Ty); 377 const SCEV *getSignExtendExpr(const SCEV *Op, const Type *Ty); 378 const SCEV *getAnyExtendExpr(const SCEV *Op, const Type *Ty); 379 const SCEV *getAddExpr(SmallVectorImpl<const SCEV *> &Ops); 380 const SCEV *getAddExpr(const SCEV *LHS, const SCEV *RHS) { 381 SmallVector<const SCEV *, 2> Ops; 382 Ops.push_back(LHS); 383 Ops.push_back(RHS); 384 return getAddExpr(Ops); 385 } 386 const SCEV *getAddExpr(const SCEV *Op0, const SCEV *Op1, 387 const SCEV *Op2) { 388 SmallVector<const SCEV *, 3> Ops; 389 Ops.push_back(Op0); 390 Ops.push_back(Op1); 391 Ops.push_back(Op2); 392 return getAddExpr(Ops); 393 } 394 const SCEV *getMulExpr(SmallVectorImpl<const SCEV *> &Ops); 395 const SCEV *getMulExpr(const SCEV *LHS, const SCEV *RHS) { 396 SmallVector<const SCEV *, 2> Ops; 397 Ops.push_back(LHS); 398 Ops.push_back(RHS); 399 return getMulExpr(Ops); 400 } 401 const SCEV *getUDivExpr(const SCEV *LHS, const SCEV *RHS); 402 const SCEV *getAddRecExpr(const SCEV *Start, const SCEV *Step, 403 const Loop *L); 404 const SCEV *getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands, 405 const Loop *L); 406 const SCEV *getAddRecExpr(const SmallVectorImpl<const SCEV *> &Operands, 407 const Loop *L) { 408 SmallVector<const SCEV *, 4> NewOp(Operands.begin(), Operands.end()); 409 return getAddRecExpr(NewOp, L); 410 } 411 const SCEV *getSMaxExpr(const SCEV *LHS, const SCEV *RHS); 412 const SCEV *getSMaxExpr(SmallVectorImpl<const SCEV *> &Operands); 413 const SCEV *getUMaxExpr(const SCEV *LHS, const SCEV *RHS); 414 const SCEV *getUMaxExpr(SmallVectorImpl<const SCEV *> &Operands); 415 const SCEV *getSMinExpr(const SCEV *LHS, const SCEV *RHS); 416 const SCEV *getUMinExpr(const SCEV *LHS, const SCEV *RHS); 417 const SCEV *getUnknown(Value *V); 418 const SCEV *getCouldNotCompute(); 419 420 /// getNegativeSCEV - Return the SCEV object corresponding to -V. 421 /// 422 const SCEV *getNegativeSCEV(const SCEV *V); 423 424 /// getNotSCEV - Return the SCEV object corresponding to ~V. 425 /// 426 const SCEV *getNotSCEV(const SCEV *V); 427 428 /// getMinusSCEV - Return LHS-RHS. 429 /// 430 const SCEV *getMinusSCEV(const SCEV *LHS, 431 const SCEV *RHS); 432 433 /// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion 434 /// of the input value to the specified type. If the type must be 435 /// extended, it is zero extended. 436 const SCEV *getTruncateOrZeroExtend(const SCEV *V, const Type *Ty); 437 438 /// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion 439 /// of the input value to the specified type. If the type must be 440 /// extended, it is sign extended. 441 const SCEV *getTruncateOrSignExtend(const SCEV *V, const Type *Ty); 442 443 /// getNoopOrZeroExtend - Return a SCEV corresponding to a conversion of 444 /// the input value to the specified type. If the type must be extended, 445 /// it is zero extended. The conversion must not be narrowing. 446 const SCEV *getNoopOrZeroExtend(const SCEV *V, const Type *Ty); 447 448 /// getNoopOrSignExtend - Return a SCEV corresponding to a conversion of 449 /// the input value to the specified type. If the type must be extended, 450 /// it is sign extended. The conversion must not be narrowing. 451 const SCEV *getNoopOrSignExtend(const SCEV *V, const Type *Ty); 452 453 /// getNoopOrAnyExtend - Return a SCEV corresponding to a conversion of 454 /// the input value to the specified type. If the type must be extended, 455 /// it is extended with unspecified bits. The conversion must not be 456 /// narrowing. 457 const SCEV *getNoopOrAnyExtend(const SCEV *V, const Type *Ty); 458 459 /// getTruncateOrNoop - Return a SCEV corresponding to a conversion of the 460 /// input value to the specified type. The conversion must not be 461 /// widening. 462 const SCEV *getTruncateOrNoop(const SCEV *V, const Type *Ty); 463 464 /// getIntegerSCEV - Given a SCEVable type, create a constant for the 465 /// specified signed integer value and return a SCEV for the constant. 466 const SCEV *getIntegerSCEV(int Val, const Type *Ty); 467 468 /// getUMaxFromMismatchedTypes - Promote the operands to the wider of 469 /// the types using zero-extension, and then perform a umax operation 470 /// with them. 471 const SCEV *getUMaxFromMismatchedTypes(const SCEV *LHS, 472 const SCEV *RHS); 473 474 /// getUMinFromMismatchedTypes - Promote the operands to the wider of 475 /// the types using zero-extension, and then perform a umin operation 476 /// with them. 477 const SCEV *getUMinFromMismatchedTypes(const SCEV *LHS, 478 const SCEV *RHS); 479 480 /// getSCEVAtScope - Return a SCEV expression handle for the specified value 481 /// at the specified scope in the program. The L value specifies a loop 482 /// nest to evaluate the expression at, where null is the top-level or a 483 /// specified loop is immediately inside of the loop. 484 /// 485 /// This method can be used to compute the exit value for a variable defined 486 /// in a loop by querying what the value will hold in the parent loop. 487 /// 488 /// In the case that a relevant loop exit value cannot be computed, the 489 /// original value V is returned. 490 const SCEV *getSCEVAtScope(const SCEV *S, const Loop *L); 491 492 /// getSCEVAtScope - This is a convenience function which does 493 /// getSCEVAtScope(getSCEV(V), L). 494 const SCEV *getSCEVAtScope(Value *V, const Loop *L); 495 496 /// isLoopGuardedByCond - Test whether entry to the loop is protected by 497 /// a conditional between LHS and RHS. This is used to help avoid max 498 /// expressions in loop trip counts. 499 bool isLoopGuardedByCond(const Loop *L, ICmpInst::Predicate Pred, 500 const SCEV *LHS, const SCEV *RHS); 501 502 /// getBackedgeTakenCount - If the specified loop has a predictable 503 /// backedge-taken count, return it, otherwise return a SCEVCouldNotCompute 504 /// object. The backedge-taken count is the number of times the loop header 505 /// will be branched to from within the loop. This is one less than the 506 /// trip count of the loop, since it doesn't count the first iteration, 507 /// when the header is branched to from outside the loop. 508 /// 509 /// Note that it is not valid to call this method on a loop without a 510 /// loop-invariant backedge-taken count (see 511 /// hasLoopInvariantBackedgeTakenCount). 512 /// 513 const SCEV *getBackedgeTakenCount(const Loop *L); 514 515 /// getMaxBackedgeTakenCount - Similar to getBackedgeTakenCount, except 516 /// return the least SCEV value that is known never to be less than the 517 /// actual backedge taken count. 518 const SCEV *getMaxBackedgeTakenCount(const Loop *L); 519 520 /// hasLoopInvariantBackedgeTakenCount - Return true if the specified loop 521 /// has an analyzable loop-invariant backedge-taken count. 522 bool hasLoopInvariantBackedgeTakenCount(const Loop *L); 523 524 /// forgetLoopBackedgeTakenCount - This method should be called by the 525 /// client when it has changed a loop in a way that may effect 526 /// ScalarEvolution's ability to compute a trip count, or if the loop 527 /// is deleted. 528 void forgetLoopBackedgeTakenCount(const Loop *L); 529 530 /// GetMinTrailingZeros - Determine the minimum number of zero bits that S 531 /// is guaranteed to end in (at every loop iteration). It is, at the same 532 /// time, the minimum number of times S is divisible by 2. For example, 533 /// given {4,+,8} it returns 2. If S is guaranteed to be 0, it returns the 534 /// bitwidth of S. 535 uint32_t GetMinTrailingZeros(const SCEV *S); 536 537 /// GetMinLeadingZeros - Determine the minimum number of zero bits that S is 538 /// guaranteed to begin with (at every loop iteration). 539 uint32_t GetMinLeadingZeros(const SCEV *S); 540 541 /// GetMinSignBits - Determine the minimum number of sign bits that S is 542 /// guaranteed to begin with. 543 uint32_t GetMinSignBits(const SCEV *S); 544 545 virtual bool runOnFunction(Function &F); 546 virtual void releaseMemory(); 547 virtual void getAnalysisUsage(AnalysisUsage &AU) const; 548 void print(raw_ostream &OS, const Module* = 0) const; 549 virtual void print(std::ostream &OS, const Module* = 0) const; 550 void print(std::ostream *OS, const Module* M = 0) const { 551 if (OS) print(*OS, M); 552 } 553 554 private: 555 FoldingSet<SCEV> UniqueSCEVs; 556 BumpPtrAllocator SCEVAllocator; 557 }; 558} 559 560#endif 561