ScalarEvolution.h revision 4d289bf4af88759be173a1a809bf8c092d729764
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/ADT/DenseMap.h" 29#include <iosfwd> 30 31namespace llvm { 32 class APInt; 33 class ConstantInt; 34 class Type; 35 class ScalarEvolution; 36 class TargetData; 37 class SCEVConstant; 38 class SCEVTruncateExpr; 39 class SCEVZeroExtendExpr; 40 class SCEVCommutativeExpr; 41 class SCEVUDivExpr; 42 class SCEVSignExtendExpr; 43 class SCEVAddRecExpr; 44 class SCEVUnknown; 45 46 /// SCEV - This class represents an analyzed expression in the program. These 47 /// are reference-counted opaque objects that the client is not allowed to 48 /// do much with directly. 49 /// 50 class SCEV { 51 const unsigned SCEVType; // The SCEV baseclass this node corresponds to 52 53 SCEV(const SCEV &); // DO NOT IMPLEMENT 54 void operator=(const SCEV &); // DO NOT IMPLEMENT 55 protected: 56 virtual ~SCEV(); 57 public: 58 explicit SCEV(unsigned SCEVTy) : 59 SCEVType(SCEVTy) {} 60 61 unsigned getSCEVType() const { return SCEVType; } 62 63 /// isLoopInvariant - Return true if the value of this SCEV is unchanging in 64 /// the specified loop. 65 virtual bool isLoopInvariant(const Loop *L) const = 0; 66 67 /// hasComputableLoopEvolution - Return true if this SCEV changes value in a 68 /// known way in the specified loop. This property being true implies that 69 /// the value is variant in the loop AND that we can emit an expression to 70 /// compute the value of the expression at any particular loop iteration. 71 virtual bool hasComputableLoopEvolution(const Loop *L) const = 0; 72 73 /// getType - Return the LLVM type of this SCEV expression. 74 /// 75 virtual const Type *getType() const = 0; 76 77 /// isZero - Return true if the expression is a constant zero. 78 /// 79 bool isZero() const; 80 81 /// isOne - Return true if the expression is a constant one. 82 /// 83 bool isOne() const; 84 85 /// isAllOnesValue - Return true if the expression is a constant 86 /// all-ones value. 87 /// 88 bool isAllOnesValue() const; 89 90 /// replaceSymbolicValuesWithConcrete - If this SCEV internally references 91 /// the symbolic value "Sym", construct and return a new SCEV that produces 92 /// the same value, but which uses the concrete value Conc instead of the 93 /// symbolic value. If this SCEV does not use the symbolic value, it 94 /// returns itself. 95 virtual const SCEV* 96 replaceSymbolicValuesWithConcrete(const SCEV* Sym, 97 const SCEV* Conc, 98 ScalarEvolution &SE) const = 0; 99 100 /// dominates - Return true if elements that makes up this SCEV dominates 101 /// the specified basic block. 102 virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const = 0; 103 104 /// print - Print out the internal representation of this scalar to the 105 /// specified stream. This should really only be used for debugging 106 /// purposes. 107 virtual void print(raw_ostream &OS) const = 0; 108 void print(std::ostream &OS) const; 109 void print(std::ostream *OS) const { if (OS) print(*OS); } 110 111 /// dump - This method is used for debugging. 112 /// 113 void dump() const; 114 }; 115 116 inline raw_ostream &operator<<(raw_ostream &OS, const SCEV &S) { 117 S.print(OS); 118 return OS; 119 } 120 121 inline std::ostream &operator<<(std::ostream &OS, const SCEV &S) { 122 S.print(OS); 123 return OS; 124 } 125 126 /// SCEVCouldNotCompute - An object of this class is returned by queries that 127 /// could not be answered. For example, if you ask for the number of 128 /// iterations of a linked-list traversal loop, you will get one of these. 129 /// None of the standard SCEV operations are valid on this class, it is just a 130 /// marker. 131 struct SCEVCouldNotCompute : public SCEV { 132 SCEVCouldNotCompute(); 133 134 // None of these methods are valid for this object. 135 virtual bool isLoopInvariant(const Loop *L) const; 136 virtual const Type *getType() const; 137 virtual bool hasComputableLoopEvolution(const Loop *L) const; 138 virtual void print(raw_ostream &OS) const; 139 virtual const SCEV* 140 replaceSymbolicValuesWithConcrete(const SCEV* Sym, 141 const SCEV* Conc, 142 ScalarEvolution &SE) const; 143 144 virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const { 145 return true; 146 } 147 148 /// Methods for support type inquiry through isa, cast, and dyn_cast: 149 static inline bool classof(const SCEVCouldNotCompute *S) { return true; } 150 static bool classof(const SCEV *S); 151 }; 152 153 /// ScalarEvolution - This class is the main scalar evolution driver. Because 154 /// client code (intentionally) can't do much with the SCEV objects directly, 155 /// they must ask this class for services. 156 /// 157 class ScalarEvolution : public FunctionPass { 158 /// SCEVCallbackVH - A CallbackVH to arrange for ScalarEvolution to be 159 /// notified whenever a Value is deleted. 160 class SCEVCallbackVH : public CallbackVH { 161 ScalarEvolution *SE; 162 virtual void deleted(); 163 virtual void allUsesReplacedWith(Value *New); 164 public: 165 SCEVCallbackVH(Value *V, ScalarEvolution *SE = 0); 166 }; 167 168 friend class SCEVCallbackVH; 169 friend class SCEVExpander; 170 171 /// F - The function we are analyzing. 172 /// 173 Function *F; 174 175 /// LI - The loop information for the function we are currently analyzing. 176 /// 177 LoopInfo *LI; 178 179 /// TD - The target data information for the target we are targetting. 180 /// 181 TargetData *TD; 182 183 /// CouldNotCompute - This SCEV is used to represent unknown trip 184 /// counts and things. 185 const SCEV* CouldNotCompute; 186 187 /// Scalars - This is a cache of the scalars we have analyzed so far. 188 /// 189 std::map<SCEVCallbackVH, const SCEV*> Scalars; 190 191 /// BackedgeTakenInfo - Information about the backedge-taken count 192 /// of a loop. This currently inclues an exact count and a maximum count. 193 /// 194 struct BackedgeTakenInfo { 195 /// Exact - An expression indicating the exact backedge-taken count of 196 /// the loop if it is known, or a SCEVCouldNotCompute otherwise. 197 const SCEV* Exact; 198 199 /// Exact - An expression indicating the least maximum backedge-taken 200 /// count of the loop that is known, or a SCEVCouldNotCompute. 201 const SCEV* Max; 202 203 /*implicit*/ BackedgeTakenInfo(const SCEV* exact) : 204 Exact(exact), Max(exact) {} 205 206 BackedgeTakenInfo(const SCEV* exact, const SCEV* max) : 207 Exact(exact), Max(max) {} 208 209 /// hasAnyInfo - Test whether this BackedgeTakenInfo contains any 210 /// computed information, or whether it's all SCEVCouldNotCompute 211 /// values. 212 bool hasAnyInfo() const { 213 return !isa<SCEVCouldNotCompute>(Exact) || 214 !isa<SCEVCouldNotCompute>(Max); 215 } 216 }; 217 218 /// BackedgeTakenCounts - Cache the backedge-taken count of the loops for 219 /// this function as they are computed. 220 std::map<const Loop*, BackedgeTakenInfo> BackedgeTakenCounts; 221 222 /// ConstantEvolutionLoopExitValue - This map contains entries for all of 223 /// the PHI instructions that we attempt to compute constant evolutions for. 224 /// This allows us to avoid potentially expensive recomputation of these 225 /// properties. An instruction maps to null if we are unable to compute its 226 /// exit value. 227 std::map<PHINode*, Constant*> ConstantEvolutionLoopExitValue; 228 229 /// ValuesAtScopes - This map contains entries for all the instructions 230 /// that we attempt to compute getSCEVAtScope information for without 231 /// using SCEV techniques, which can be expensive. 232 std::map<Instruction *, std::map<const Loop *, Constant *> > ValuesAtScopes; 233 234 /// createSCEV - We know that there is no SCEV for the specified value. 235 /// Analyze the expression. 236 const SCEV* createSCEV(Value *V); 237 238 /// createNodeForPHI - Provide the special handling we need to analyze PHI 239 /// SCEVs. 240 const SCEV* createNodeForPHI(PHINode *PN); 241 242 /// createNodeForGEP - Provide the special handling we need to analyze GEP 243 /// SCEVs. 244 const SCEV* createNodeForGEP(User *GEP); 245 246 /// ReplaceSymbolicValueWithConcrete - This looks up the computed SCEV value 247 /// for the specified instruction and replaces any references to the 248 /// symbolic value SymName with the specified value. This is used during 249 /// PHI resolution. 250 void ReplaceSymbolicValueWithConcrete(Instruction *I, 251 const SCEV* SymName, 252 const SCEV* NewVal); 253 254 /// getBECount - Subtract the end and start values and divide by the step, 255 /// rounding up, to get the number of times the backedge is executed. Return 256 /// CouldNotCompute if an intermediate computation overflows. 257 const SCEV* getBECount(const SCEV* Start, 258 const SCEV* End, 259 const SCEV* Step); 260 261 /// getBackedgeTakenInfo - Return the BackedgeTakenInfo for the given 262 /// loop, lazily computing new values if the loop hasn't been analyzed 263 /// yet. 264 const BackedgeTakenInfo &getBackedgeTakenInfo(const Loop *L); 265 266 /// ComputeBackedgeTakenCount - Compute the number of times the specified 267 /// loop will iterate. 268 BackedgeTakenInfo ComputeBackedgeTakenCount(const Loop *L); 269 270 /// ComputeBackedgeTakenCountFromExit - Compute the number of times the 271 /// backedge of the specified loop will execute if it exits via the 272 /// specified block. 273 BackedgeTakenInfo ComputeBackedgeTakenCountFromExit(const Loop *L, 274 BasicBlock *ExitingBlock); 275 276 /// ComputeBackedgeTakenCountFromExitCond - Compute the number of times the 277 /// backedge of the specified loop will execute if its exit condition 278 /// were a conditional branch of ExitCond, TBB, and FBB. 279 BackedgeTakenInfo 280 ComputeBackedgeTakenCountFromExitCond(const Loop *L, 281 Value *ExitCond, 282 BasicBlock *TBB, 283 BasicBlock *FBB); 284 285 /// ComputeBackedgeTakenCountFromExitCondICmp - Compute the number of 286 /// times the backedge of the specified loop will execute if its exit 287 /// condition were a conditional branch of the ICmpInst ExitCond, TBB, 288 /// and FBB. 289 BackedgeTakenInfo 290 ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L, 291 ICmpInst *ExitCond, 292 BasicBlock *TBB, 293 BasicBlock *FBB); 294 295 /// ComputeLoadConstantCompareBackedgeTakenCount - Given an exit condition 296 /// of 'icmp op load X, cst', try to see if we can compute the trip count. 297 const SCEV* 298 ComputeLoadConstantCompareBackedgeTakenCount(LoadInst *LI, 299 Constant *RHS, 300 const Loop *L, 301 ICmpInst::Predicate p); 302 303 /// ComputeBackedgeTakenCountExhaustively - If the trip is known to execute 304 /// a constant number of times (the condition evolves only from constants), 305 /// try to evaluate a few iterations of the loop until we get the exit 306 /// condition gets a value of ExitWhen (true or false). If we cannot 307 /// evaluate the trip count of the loop, return CouldNotCompute. 308 const SCEV* ComputeBackedgeTakenCountExhaustively(const Loop *L, Value *Cond, 309 bool ExitWhen); 310 311 /// HowFarToZero - Return the number of times a backedge comparing the 312 /// specified value to zero will execute. If not computable, return 313 /// CouldNotCompute. 314 const SCEV* HowFarToZero(const SCEV *V, const Loop *L); 315 316 /// HowFarToNonZero - Return the number of times a backedge checking the 317 /// specified value for nonzero will execute. If not computable, return 318 /// CouldNotCompute. 319 const SCEV* HowFarToNonZero(const SCEV *V, const Loop *L); 320 321 /// HowManyLessThans - Return the number of times a backedge containing the 322 /// specified less-than comparison will execute. If not computable, return 323 /// CouldNotCompute. isSigned specifies whether the less-than is signed. 324 BackedgeTakenInfo HowManyLessThans(const SCEV *LHS, const SCEV *RHS, 325 const Loop *L, bool isSigned); 326 327 /// getLoopPredecessor - If the given loop's header has exactly one unique 328 /// predecessor outside the loop, return it. Otherwise return null. 329 BasicBlock *getLoopPredecessor(const Loop *L); 330 331 /// getPredecessorWithUniqueSuccessorForBB - Return a predecessor of BB 332 /// (which may not be an immediate predecessor) which has exactly one 333 /// successor from which BB is reachable, or null if no such block is 334 /// found. 335 BasicBlock* getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB); 336 337 /// getConstantEvolutionLoopExitValue - If we know that the specified Phi is 338 /// in the header of its containing loop, we know the loop executes a 339 /// constant number of times, and the PHI node is just a recurrence 340 /// involving constants, fold it. 341 Constant *getConstantEvolutionLoopExitValue(PHINode *PN, const APInt& BEs, 342 const Loop *L); 343 344 /// forgetLoopPHIs - Delete the memoized SCEVs associated with the 345 /// PHI nodes in the given loop. This is used when the trip count of 346 /// the loop may have changed. 347 void forgetLoopPHIs(const Loop *L); 348 349 public: 350 static char ID; // Pass identification, replacement for typeid 351 ScalarEvolution(); 352 353 /// isSCEVable - Test if values of the given type are analyzable within 354 /// the SCEV framework. This primarily includes integer types, and it 355 /// can optionally include pointer types if the ScalarEvolution class 356 /// has access to target-specific information. 357 bool isSCEVable(const Type *Ty) const; 358 359 /// getTypeSizeInBits - Return the size in bits of the specified type, 360 /// for which isSCEVable must return true. 361 uint64_t getTypeSizeInBits(const Type *Ty) const; 362 363 /// getEffectiveSCEVType - Return a type with the same bitwidth as 364 /// the given type and which represents how SCEV will treat the given 365 /// type, for which isSCEVable must return true. For pointer types, 366 /// this is the pointer-sized integer type. 367 const Type *getEffectiveSCEVType(const Type *Ty) const; 368 369 /// getSCEV - Return a SCEV expression handle for the full generality of the 370 /// specified expression. 371 const SCEV* getSCEV(Value *V); 372 373 const SCEV* getConstant(ConstantInt *V); 374 const SCEV* getConstant(const APInt& Val); 375 const SCEV* getConstant(const Type *Ty, uint64_t V, bool isSigned = false); 376 const SCEV* getTruncateExpr(const SCEV* Op, const Type *Ty); 377 const SCEV* getZeroExtendExpr(const SCEV* Op, const Type *Ty); 378 const SCEV* getSignExtendExpr(const SCEV* Op, const Type *Ty); 379 const SCEV* getAnyExtendExpr(const SCEV* Op, const Type *Ty); 380 const SCEV* getAddExpr(SmallVectorImpl<const SCEV*> &Ops); 381 const SCEV* getAddExpr(const SCEV* LHS, const SCEV* RHS) { 382 SmallVector<const SCEV*, 2> Ops; 383 Ops.push_back(LHS); 384 Ops.push_back(RHS); 385 return getAddExpr(Ops); 386 } 387 const SCEV* getAddExpr(const SCEV* Op0, const SCEV* Op1, 388 const SCEV* Op2) { 389 SmallVector<const SCEV*, 3> Ops; 390 Ops.push_back(Op0); 391 Ops.push_back(Op1); 392 Ops.push_back(Op2); 393 return getAddExpr(Ops); 394 } 395 const SCEV* getMulExpr(SmallVectorImpl<const SCEV*> &Ops); 396 const SCEV* getMulExpr(const SCEV* LHS, const SCEV* RHS) { 397 SmallVector<const SCEV*, 2> Ops; 398 Ops.push_back(LHS); 399 Ops.push_back(RHS); 400 return getMulExpr(Ops); 401 } 402 const SCEV* getUDivExpr(const SCEV* LHS, const SCEV* RHS); 403 const SCEV* getAddRecExpr(const SCEV* Start, const SCEV* Step, 404 const Loop *L); 405 const SCEV* getAddRecExpr(SmallVectorImpl<const SCEV*> &Operands, 406 const Loop *L); 407 const SCEV* getAddRecExpr(const SmallVectorImpl<const SCEV*> &Operands, 408 const Loop *L) { 409 SmallVector<const SCEV*, 4> NewOp(Operands.begin(), Operands.end()); 410 return getAddRecExpr(NewOp, L); 411 } 412 const SCEV* getSMaxExpr(const SCEV* LHS, const SCEV* RHS); 413 const SCEV* getSMaxExpr(SmallVectorImpl<const SCEV*> &Operands); 414 const SCEV* getUMaxExpr(const SCEV* LHS, const SCEV* RHS); 415 const SCEV* getUMaxExpr(SmallVectorImpl<const SCEV*> &Operands); 416 const SCEV* getSMinExpr(const SCEV* LHS, const SCEV* RHS); 417 const SCEV* getUMinExpr(const SCEV* LHS, const SCEV* RHS); 418 const SCEV* getUnknown(Value *V); 419 const SCEV* getCouldNotCompute(); 420 421 /// getNegativeSCEV - Return the SCEV object corresponding to -V. 422 /// 423 const SCEV* getNegativeSCEV(const SCEV* V); 424 425 /// getNotSCEV - Return the SCEV object corresponding to ~V. 426 /// 427 const SCEV* getNotSCEV(const SCEV* V); 428 429 /// getMinusSCEV - Return LHS-RHS. 430 /// 431 const SCEV* getMinusSCEV(const SCEV* LHS, 432 const SCEV* RHS); 433 434 /// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion 435 /// of the input value to the specified type. If the type must be 436 /// extended, it is zero extended. 437 const SCEV* getTruncateOrZeroExtend(const SCEV* V, const Type *Ty); 438 439 /// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion 440 /// of the input value to the specified type. If the type must be 441 /// extended, it is sign extended. 442 const SCEV* getTruncateOrSignExtend(const SCEV* V, const Type *Ty); 443 444 /// getNoopOrZeroExtend - Return a SCEV corresponding to a conversion of 445 /// the input value to the specified type. If the type must be extended, 446 /// it is zero extended. The conversion must not be narrowing. 447 const SCEV* getNoopOrZeroExtend(const SCEV* V, const Type *Ty); 448 449 /// getNoopOrSignExtend - Return a SCEV corresponding to a conversion of 450 /// the input value to the specified type. If the type must be extended, 451 /// it is sign extended. The conversion must not be narrowing. 452 const SCEV* getNoopOrSignExtend(const SCEV* V, const Type *Ty); 453 454 /// getNoopOrAnyExtend - Return a SCEV corresponding to a conversion of 455 /// the input value to the specified type. If the type must be extended, 456 /// it is extended with unspecified bits. The conversion must not be 457 /// narrowing. 458 const SCEV* getNoopOrAnyExtend(const SCEV* V, const Type *Ty); 459 460 /// getTruncateOrNoop - Return a SCEV corresponding to a conversion of the 461 /// input value to the specified type. The conversion must not be 462 /// widening. 463 const SCEV* getTruncateOrNoop(const SCEV* V, const Type *Ty); 464 465 /// getIntegerSCEV - Given an integer or FP type, create a constant for the 466 /// specified signed integer value and return a SCEV for the constant. 467 const SCEV* getIntegerSCEV(int Val, const Type *Ty); 468 469 /// getUMaxFromMismatchedTypes - Promote the operands to the wider of 470 /// the types using zero-extension, and then perform a umax operation 471 /// with them. 472 const SCEV* getUMaxFromMismatchedTypes(const SCEV* LHS, 473 const SCEV* RHS); 474 475 /// getUMinFromMismatchedTypes - Promote the operands to the wider of 476 /// the types using zero-extension, and then perform a umin operation 477 /// with them. 478 const SCEV* getUMinFromMismatchedTypes(const SCEV* LHS, 479 const SCEV* RHS); 480 481 /// hasSCEV - Return true if the SCEV for this value has already been 482 /// computed. 483 bool hasSCEV(Value *V) const; 484 485 /// setSCEV - Insert the specified SCEV into the map of current SCEVs for 486 /// the specified value. 487 void setSCEV(Value *V, const SCEV* H); 488 489 /// getSCEVAtScope - Return a SCEV expression handle for the specified value 490 /// at the specified scope in the program. The L value specifies a loop 491 /// nest to evaluate the expression at, where null is the top-level or a 492 /// specified loop is immediately inside of the loop. 493 /// 494 /// This method can be used to compute the exit value for a variable defined 495 /// in a loop by querying what the value will hold in the parent loop. 496 /// 497 /// In the case that a relevant loop exit value cannot be computed, the 498 /// original value V is returned. 499 const SCEV* getSCEVAtScope(const SCEV *S, const Loop *L); 500 501 /// getSCEVAtScope - This is a convenience function which does 502 /// getSCEVAtScope(getSCEV(V), L). 503 const SCEV* getSCEVAtScope(Value *V, const Loop *L); 504 505 /// isLoopGuardedByCond - Test whether entry to the loop is protected by 506 /// a conditional between LHS and RHS. This is used to help avoid max 507 /// expressions in loop trip counts. 508 bool isLoopGuardedByCond(const Loop *L, ICmpInst::Predicate Pred, 509 const SCEV *LHS, const SCEV *RHS); 510 511 /// getBackedgeTakenCount - If the specified loop has a predictable 512 /// backedge-taken count, return it, otherwise return a SCEVCouldNotCompute 513 /// object. The backedge-taken count is the number of times the loop header 514 /// will be branched to from within the loop. This is one less than the 515 /// trip count of the loop, since it doesn't count the first iteration, 516 /// when the header is branched to from outside the loop. 517 /// 518 /// Note that it is not valid to call this method on a loop without a 519 /// loop-invariant backedge-taken count (see 520 /// hasLoopInvariantBackedgeTakenCount). 521 /// 522 const SCEV* getBackedgeTakenCount(const Loop *L); 523 524 /// getMaxBackedgeTakenCount - Similar to getBackedgeTakenCount, except 525 /// return the least SCEV value that is known never to be less than the 526 /// actual backedge taken count. 527 const SCEV* getMaxBackedgeTakenCount(const Loop *L); 528 529 /// hasLoopInvariantBackedgeTakenCount - Return true if the specified loop 530 /// has an analyzable loop-invariant backedge-taken count. 531 bool hasLoopInvariantBackedgeTakenCount(const Loop *L); 532 533 /// forgetLoopBackedgeTakenCount - This method should be called by the 534 /// client when it has changed a loop in a way that may effect 535 /// ScalarEvolution's ability to compute a trip count, or if the loop 536 /// is deleted. 537 void forgetLoopBackedgeTakenCount(const Loop *L); 538 539 /// GetMinTrailingZeros - Determine the minimum number of zero bits that S is 540 /// guaranteed to end in (at every loop iteration). It is, at the same time, 541 /// the minimum number of times S is divisible by 2. For example, given {4,+,8} 542 /// it returns 2. If S is guaranteed to be 0, it returns the bitwidth of S. 543 uint32_t GetMinTrailingZeros(const SCEV* S); 544 545 /// GetMinLeadingZeros - Determine the minimum number of zero bits that S is 546 /// guaranteed to begin with (at every loop iteration). 547 uint32_t GetMinLeadingZeros(const SCEV* S); 548 549 /// GetMinSignBits - Determine the minimum number of sign bits that S is 550 /// guaranteed to begin with. 551 uint32_t GetMinSignBits(const SCEV* S); 552 553 virtual bool runOnFunction(Function &F); 554 virtual void releaseMemory(); 555 virtual void getAnalysisUsage(AnalysisUsage &AU) const; 556 void print(raw_ostream &OS, const Module* = 0) const; 557 virtual void print(std::ostream &OS, const Module* = 0) const; 558 void print(std::ostream *OS, const Module* M = 0) const { 559 if (OS) print(*OS, M); 560 } 561 562 private: 563 // Uniquing tables. 564 std::map<ConstantInt*, SCEVConstant*> SCEVConstants; 565 std::map<std::pair<const SCEV*, const Type*>, 566 SCEVTruncateExpr*> SCEVTruncates; 567 std::map<std::pair<const SCEV*, const Type*>, 568 SCEVZeroExtendExpr*> SCEVZeroExtends; 569 std::map<std::pair<unsigned, std::vector<const SCEV*> >, 570 SCEVCommutativeExpr*> SCEVCommExprs; 571 std::map<std::pair<const SCEV*, const SCEV*>, 572 SCEVUDivExpr*> SCEVUDivs; 573 std::map<std::pair<const SCEV*, const Type*>, 574 SCEVSignExtendExpr*> SCEVSignExtends; 575 std::map<std::pair<const Loop *, std::vector<const SCEV*> >, 576 SCEVAddRecExpr*> SCEVAddRecExprs; 577 std::map<Value*, SCEVUnknown*> SCEVUnknowns; 578 }; 579} 580 581#endif 582