1 //===- llvm/Analysis/ScalarEvolution.h - Scalar Evolution -------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // The ScalarEvolution class is an LLVM pass which can be used to analyze and
11 // categorize 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.
16 // This analysis is primarily useful for induction variable substitution and
17 // strength reduction.
19 //===----------------------------------------------------------------------===//
21 #ifndef LLVM_ANALYSIS_SCALAREVOLUTION_H
22 #define LLVM_ANALYSIS_SCALAREVOLUTION_H
24 #include "llvm/Pass.h"
25 #include "llvm/Instructions.h"
26 #include "llvm/Function.h"
27 #include "llvm/System/DataTypes.h"
28 #include "llvm/Support/ValueHandle.h"
29 #include "llvm/Support/Allocator.h"
30 #include "llvm/Support/ConstantRange.h"
31 #include "llvm/ADT/FoldingSet.h"
32 #include "llvm/ADT/DenseMap.h"
41 class ScalarEvolution;
49 template<> struct FoldingSetTrait<SCEV>;
51 /// SCEV - This class represents an analyzed expression in the program. These
52 /// are opaque objects that the client is not allowed to do much with
55 class SCEV : public FoldingSetNode {
56 friend struct FoldingSetTrait<SCEV>;
58 /// FastID - A reference to an Interned FoldingSetNodeID for this node.
59 /// The ScalarEvolution's BumpPtrAllocator holds the data.
60 FoldingSetNodeIDRef FastID;
62 // The SCEV baseclass this node corresponds to
63 const unsigned short SCEVType;
66 /// SubclassData - This field is initialized to zero and may be used in
67 /// subclasses to store miscellaneous information.
68 unsigned short SubclassData;
71 SCEV(const SCEV &); // DO NOT IMPLEMENT
72 void operator=(const SCEV &); // DO NOT IMPLEMENT
75 explicit SCEV(const FoldingSetNodeIDRef ID, unsigned SCEVTy) :
76 FastID(ID), SCEVType(SCEVTy), SubclassData(0) {}
78 unsigned getSCEVType() const { return SCEVType; }
80 /// getType - Return the LLVM type of this SCEV expression.
82 const Type *getType() const;
84 /// isZero - Return true if the expression is a constant zero.
88 /// isOne - Return true if the expression is a constant one.
92 /// isAllOnesValue - Return true if the expression is a constant
95 bool isAllOnesValue() const;
97 /// print - Print out the internal representation of this scalar to the
98 /// specified stream. This should really only be used for debugging
100 void print(raw_ostream &OS) const;
102 /// dump - This method is used for debugging.
107 // Specialize FoldingSetTrait for SCEV to avoid needing to compute
108 // temporary FoldingSetNodeID values.
109 template<> struct FoldingSetTrait<SCEV> : DefaultFoldingSetTrait<SCEV> {
110 static void Profile(const SCEV &X, FoldingSetNodeID& ID) {
113 static bool Equals(const SCEV &X, const FoldingSetNodeID &ID,
114 FoldingSetNodeID &TempID) {
115 return ID == X.FastID;
117 static unsigned ComputeHash(const SCEV &X, FoldingSetNodeID &TempID) {
118 return X.FastID.ComputeHash();
122 inline raw_ostream &operator<<(raw_ostream &OS, const SCEV &S) {
127 /// SCEVCouldNotCompute - An object of this class is returned by queries that
128 /// could not be answered. For example, if you ask for the number of
129 /// iterations of a linked-list traversal loop, you will get one of these.
130 /// None of the standard SCEV operations are valid on this class, it is just a
132 struct SCEVCouldNotCompute : public SCEV {
133 SCEVCouldNotCompute();
135 /// Methods for support type inquiry through isa, cast, and dyn_cast:
136 static inline bool classof(const SCEVCouldNotCompute *S) { return true; }
137 static bool classof(const SCEV *S);
140 /// ScalarEvolution - This class is the main scalar evolution driver. Because
141 /// client code (intentionally) can't do much with the SCEV objects directly,
142 /// they must ask this class for services.
144 class ScalarEvolution : public FunctionPass {
145 /// SCEVCallbackVH - A CallbackVH to arrange for ScalarEvolution to be
146 /// notified whenever a Value is deleted.
147 class SCEVCallbackVH : public CallbackVH {
149 virtual void deleted();
150 virtual void allUsesReplacedWith(Value *New);
152 SCEVCallbackVH(Value *V, ScalarEvolution *SE = 0);
155 friend class SCEVCallbackVH;
156 friend class SCEVExpander;
157 friend class SCEVUnknown;
159 /// F - The function we are analyzing.
163 /// LI - The loop information for the function we are currently analyzing.
167 /// TD - The target data information for the target we are targeting.
171 /// DT - The dominator tree.
175 /// CouldNotCompute - This SCEV is used to represent unknown trip
176 /// counts and things.
177 SCEVCouldNotCompute CouldNotCompute;
179 /// ValueExprMapType - The typedef for ValueExprMap.
181 typedef DenseMap<SCEVCallbackVH, const SCEV *, DenseMapInfo<Value *> >
184 /// ValueExprMap - This is a cache of the values we have analyzed so far.
186 ValueExprMapType ValueExprMap;
188 /// BackedgeTakenInfo - Information about the backedge-taken count
189 /// of a loop. This currently includes an exact count and a maximum count.
191 struct BackedgeTakenInfo {
192 /// Exact - An expression indicating the exact backedge-taken count of
193 /// the loop if it is known, or a SCEVCouldNotCompute otherwise.
196 /// Max - An expression indicating the least maximum backedge-taken
197 /// count of the loop that is known, or a SCEVCouldNotCompute.
200 /*implicit*/ BackedgeTakenInfo(const SCEV *exact) :
201 Exact(exact), Max(exact) {}
203 BackedgeTakenInfo(const SCEV *exact, const SCEV *max) :
204 Exact(exact), Max(max) {}
206 /// hasAnyInfo - Test whether this BackedgeTakenInfo contains any
207 /// computed information, or whether it's all SCEVCouldNotCompute
209 bool hasAnyInfo() const {
210 return !isa<SCEVCouldNotCompute>(Exact) ||
211 !isa<SCEVCouldNotCompute>(Max);
215 /// BackedgeTakenCounts - Cache the backedge-taken count of the loops for
216 /// this function as they are computed.
217 std::map<const Loop*, BackedgeTakenInfo> BackedgeTakenCounts;
219 /// ConstantEvolutionLoopExitValue - This map contains entries for all of
220 /// the PHI instructions that we attempt to compute constant evolutions for.
221 /// This allows us to avoid potentially expensive recomputation of these
222 /// properties. An instruction maps to null if we are unable to compute its
224 std::map<PHINode*, Constant*> ConstantEvolutionLoopExitValue;
226 /// ValuesAtScopes - This map contains entries for all the expressions
227 /// that we attempt to compute getSCEVAtScope information for, which can
228 /// be expensive in extreme cases.
229 std::map<const SCEV *,
230 std::map<const Loop *, const SCEV *> > ValuesAtScopes;
232 /// UnsignedRanges - Memoized results from getUnsignedRange
233 DenseMap<const SCEV *, ConstantRange> UnsignedRanges;
235 /// SignedRanges - Memoized results from getSignedRange
236 DenseMap<const SCEV *, ConstantRange> SignedRanges;
238 /// setUnsignedRange - Set the memoized unsigned range for the given SCEV.
239 const ConstantRange &setUnsignedRange(const SCEV *S,
240 const ConstantRange &CR) {
241 std::pair<DenseMap<const SCEV *, ConstantRange>::iterator, bool> Pair =
242 UnsignedRanges.insert(std::make_pair(S, CR));
244 Pair.first->second = CR;
245 return Pair.first->second;
248 /// setUnsignedRange - Set the memoized signed range for the given SCEV.
249 const ConstantRange &setSignedRange(const SCEV *S,
250 const ConstantRange &CR) {
251 std::pair<DenseMap<const SCEV *, ConstantRange>::iterator, bool> Pair =
252 SignedRanges.insert(std::make_pair(S, CR));
254 Pair.first->second = CR;
255 return Pair.first->second;
258 /// createSCEV - We know that there is no SCEV for the specified value.
259 /// Analyze the expression.
260 const SCEV *createSCEV(Value *V);
262 /// createNodeForPHI - Provide the special handling we need to analyze PHI
264 const SCEV *createNodeForPHI(PHINode *PN);
266 /// createNodeForGEP - Provide the special handling we need to analyze GEP
268 const SCEV *createNodeForGEP(GEPOperator *GEP);
270 /// computeSCEVAtScope - Implementation code for getSCEVAtScope; called
271 /// at most once for each SCEV+Loop pair.
273 const SCEV *computeSCEVAtScope(const SCEV *S, const Loop *L);
275 /// ForgetSymbolicValue - This looks up computed SCEV values for all
276 /// instructions that depend on the given instruction and removes them from
277 /// the ValueExprMap map if they reference SymName. This is used during PHI
279 void ForgetSymbolicName(Instruction *I, const SCEV *SymName);
281 /// getBECount - Subtract the end and start values and divide by the step,
282 /// rounding up, to get the number of times the backedge is executed. Return
283 /// CouldNotCompute if an intermediate computation overflows.
284 const SCEV *getBECount(const SCEV *Start,
289 /// getBackedgeTakenInfo - Return the BackedgeTakenInfo for the given
290 /// loop, lazily computing new values if the loop hasn't been analyzed
292 const BackedgeTakenInfo &getBackedgeTakenInfo(const Loop *L);
294 /// ComputeBackedgeTakenCount - Compute the number of times the specified
295 /// loop will iterate.
296 BackedgeTakenInfo ComputeBackedgeTakenCount(const Loop *L);
298 /// ComputeBackedgeTakenCountFromExit - Compute the number of times the
299 /// backedge of the specified loop will execute if it exits via the
301 BackedgeTakenInfo ComputeBackedgeTakenCountFromExit(const Loop *L,
302 BasicBlock *ExitingBlock);
304 /// ComputeBackedgeTakenCountFromExitCond - Compute the number of times the
305 /// backedge of the specified loop will execute if its exit condition
306 /// were a conditional branch of ExitCond, TBB, and FBB.
308 ComputeBackedgeTakenCountFromExitCond(const Loop *L,
313 /// ComputeBackedgeTakenCountFromExitCondICmp - Compute the number of
314 /// times the backedge of the specified loop will execute if its exit
315 /// condition were a conditional branch of the ICmpInst ExitCond, TBB,
318 ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L,
323 /// ComputeLoadConstantCompareBackedgeTakenCount - Given an exit condition
324 /// of 'icmp op load X, cst', try to see if we can compute the
325 /// backedge-taken count.
327 ComputeLoadConstantCompareBackedgeTakenCount(LoadInst *LI,
330 ICmpInst::Predicate p);
332 /// ComputeBackedgeTakenCountExhaustively - If the loop is known to execute
333 /// a constant number of times (the condition evolves only from constants),
334 /// try to evaluate a few iterations of the loop until we get the exit
335 /// condition gets a value of ExitWhen (true or false). If we cannot
336 /// evaluate the backedge-taken count of the loop, return CouldNotCompute.
337 const SCEV *ComputeBackedgeTakenCountExhaustively(const Loop *L,
341 /// HowFarToZero - Return the number of times a backedge comparing the
342 /// specified value to zero will execute. If not computable, return
344 BackedgeTakenInfo HowFarToZero(const SCEV *V, const Loop *L);
346 /// HowFarToNonZero - Return the number of times a backedge checking the
347 /// specified value for nonzero will execute. If not computable, return
349 BackedgeTakenInfo HowFarToNonZero(const SCEV *V, const Loop *L);
351 /// HowManyLessThans - Return the number of times a backedge containing the
352 /// specified less-than comparison will execute. If not computable, return
353 /// CouldNotCompute. isSigned specifies whether the less-than is signed.
354 BackedgeTakenInfo HowManyLessThans(const SCEV *LHS, const SCEV *RHS,
355 const Loop *L, bool isSigned);
357 /// getPredecessorWithUniqueSuccessorForBB - Return a predecessor of BB
358 /// (which may not be an immediate predecessor) which has exactly one
359 /// successor from which BB is reachable, or null if no such block is
361 std::pair<BasicBlock *, BasicBlock *>
362 getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB);
364 /// isImpliedCond - Test whether the condition described by Pred, LHS, and
365 /// RHS is true whenever the given FoundCondValue value evaluates to true.
366 bool isImpliedCond(ICmpInst::Predicate Pred,
367 const SCEV *LHS, const SCEV *RHS,
368 Value *FoundCondValue,
371 /// isImpliedCondOperands - Test whether the condition described by Pred,
372 /// LHS, and RHS is true whenever the condition described by Pred, FoundLHS,
373 /// and FoundRHS is true.
374 bool isImpliedCondOperands(ICmpInst::Predicate Pred,
375 const SCEV *LHS, const SCEV *RHS,
376 const SCEV *FoundLHS, const SCEV *FoundRHS);
378 /// isImpliedCondOperandsHelper - Test whether the condition described by
379 /// Pred, LHS, and RHS is true whenever the condition described by Pred,
380 /// FoundLHS, and FoundRHS is true.
381 bool isImpliedCondOperandsHelper(ICmpInst::Predicate Pred,
382 const SCEV *LHS, const SCEV *RHS,
383 const SCEV *FoundLHS, const SCEV *FoundRHS);
385 /// getConstantEvolutionLoopExitValue - If we know that the specified Phi is
386 /// in the header of its containing loop, we know the loop executes a
387 /// constant number of times, and the PHI node is just a recurrence
388 /// involving constants, fold it.
389 Constant *getConstantEvolutionLoopExitValue(PHINode *PN, const APInt& BEs,
392 /// isKnownPredicateWithRanges - Test if the given expression is known to
393 /// satisfy the condition described by Pred and the known constant ranges
396 bool isKnownPredicateWithRanges(ICmpInst::Predicate Pred,
397 const SCEV *LHS, const SCEV *RHS);
400 static char ID; // Pass identification, replacement for typeid
403 LLVMContext &getContext() const { return F->getContext(); }
405 /// isSCEVable - Test if values of the given type are analyzable within
406 /// the SCEV framework. This primarily includes integer types, and it
407 /// can optionally include pointer types if the ScalarEvolution class
408 /// has access to target-specific information.
409 bool isSCEVable(const Type *Ty) const;
411 /// getTypeSizeInBits - Return the size in bits of the specified type,
412 /// for which isSCEVable must return true.
413 uint64_t getTypeSizeInBits(const Type *Ty) const;
415 /// getEffectiveSCEVType - Return a type with the same bitwidth as
416 /// the given type and which represents how SCEV will treat the given
417 /// type, for which isSCEVable must return true. For pointer types,
418 /// this is the pointer-sized integer type.
419 const Type *getEffectiveSCEVType(const Type *Ty) const;
421 /// getSCEV - Return a SCEV expression for the full generality of the
422 /// specified expression.
423 const SCEV *getSCEV(Value *V);
425 const SCEV *getConstant(ConstantInt *V);
426 const SCEV *getConstant(const APInt& Val);
427 const SCEV *getConstant(const Type *Ty, uint64_t V, bool isSigned = false);
428 const SCEV *getTruncateExpr(const SCEV *Op, const Type *Ty);
429 const SCEV *getZeroExtendExpr(const SCEV *Op, const Type *Ty);
430 const SCEV *getSignExtendExpr(const SCEV *Op, const Type *Ty);
431 const SCEV *getAnyExtendExpr(const SCEV *Op, const Type *Ty);
432 const SCEV *getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
433 bool HasNUW = false, bool HasNSW = false);
434 const SCEV *getAddExpr(const SCEV *LHS, const SCEV *RHS,
435 bool HasNUW = false, bool HasNSW = false) {
436 SmallVector<const SCEV *, 2> Ops;
439 return getAddExpr(Ops, HasNUW, HasNSW);
441 const SCEV *getAddExpr(const SCEV *Op0, const SCEV *Op1,
443 bool HasNUW = false, bool HasNSW = false) {
444 SmallVector<const SCEV *, 3> Ops;
448 return getAddExpr(Ops, HasNUW, HasNSW);
450 const SCEV *getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
451 bool HasNUW = false, bool HasNSW = false);
452 const SCEV *getMulExpr(const SCEV *LHS, const SCEV *RHS,
453 bool HasNUW = false, bool HasNSW = false) {
454 SmallVector<const SCEV *, 2> Ops;
457 return getMulExpr(Ops, HasNUW, HasNSW);
459 const SCEV *getUDivExpr(const SCEV *LHS, const SCEV *RHS);
460 const SCEV *getAddRecExpr(const SCEV *Start, const SCEV *Step,
462 bool HasNUW = false, bool HasNSW = false);
463 const SCEV *getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
465 bool HasNUW = false, bool HasNSW = false);
466 const SCEV *getAddRecExpr(const SmallVectorImpl<const SCEV *> &Operands,
468 bool HasNUW = false, bool HasNSW = false) {
469 SmallVector<const SCEV *, 4> NewOp(Operands.begin(), Operands.end());
470 return getAddRecExpr(NewOp, L, HasNUW, HasNSW);
472 const SCEV *getSMaxExpr(const SCEV *LHS, const SCEV *RHS);
473 const SCEV *getSMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
474 const SCEV *getUMaxExpr(const SCEV *LHS, const SCEV *RHS);
475 const SCEV *getUMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
476 const SCEV *getSMinExpr(const SCEV *LHS, const SCEV *RHS);
477 const SCEV *getUMinExpr(const SCEV *LHS, const SCEV *RHS);
478 const SCEV *getUnknown(Value *V);
479 const SCEV *getCouldNotCompute();
481 /// getSizeOfExpr - Return an expression for sizeof on the given type.
483 const SCEV *getSizeOfExpr(const Type *AllocTy);
485 /// getAlignOfExpr - Return an expression for alignof on the given type.
487 const SCEV *getAlignOfExpr(const Type *AllocTy);
489 /// getOffsetOfExpr - Return an expression for offsetof on the given field.
491 const SCEV *getOffsetOfExpr(const StructType *STy, unsigned FieldNo);
493 /// getOffsetOfExpr - Return an expression for offsetof on the given field.
495 const SCEV *getOffsetOfExpr(const Type *CTy, Constant *FieldNo);
497 /// getNegativeSCEV - Return the SCEV object corresponding to -V.
499 const SCEV *getNegativeSCEV(const SCEV *V);
501 /// getNotSCEV - Return the SCEV object corresponding to ~V.
503 const SCEV *getNotSCEV(const SCEV *V);
505 /// getMinusSCEV - Return LHS-RHS.
507 const SCEV *getMinusSCEV(const SCEV *LHS,
510 /// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
511 /// of the input value to the specified type. If the type must be
512 /// extended, it is zero extended.
513 const SCEV *getTruncateOrZeroExtend(const SCEV *V, const Type *Ty);
515 /// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion
516 /// of the input value to the specified type. If the type must be
517 /// extended, it is sign extended.
518 const SCEV *getTruncateOrSignExtend(const SCEV *V, const Type *Ty);
520 /// getNoopOrZeroExtend - Return a SCEV corresponding to a conversion of
521 /// the input value to the specified type. If the type must be extended,
522 /// it is zero extended. The conversion must not be narrowing.
523 const SCEV *getNoopOrZeroExtend(const SCEV *V, const Type *Ty);
525 /// getNoopOrSignExtend - Return a SCEV corresponding to a conversion of
526 /// the input value to the specified type. If the type must be extended,
527 /// it is sign extended. The conversion must not be narrowing.
528 const SCEV *getNoopOrSignExtend(const SCEV *V, const Type *Ty);
530 /// getNoopOrAnyExtend - Return a SCEV corresponding to a conversion of
531 /// the input value to the specified type. If the type must be extended,
532 /// it is extended with unspecified bits. The conversion must not be
534 const SCEV *getNoopOrAnyExtend(const SCEV *V, const Type *Ty);
536 /// getTruncateOrNoop - Return a SCEV corresponding to a conversion of the
537 /// input value to the specified type. The conversion must not be
539 const SCEV *getTruncateOrNoop(const SCEV *V, const Type *Ty);
541 /// getUMaxFromMismatchedTypes - Promote the operands to the wider of
542 /// the types using zero-extension, and then perform a umax operation
544 const SCEV *getUMaxFromMismatchedTypes(const SCEV *LHS,
547 /// getUMinFromMismatchedTypes - Promote the operands to the wider of
548 /// the types using zero-extension, and then perform a umin operation
550 const SCEV *getUMinFromMismatchedTypes(const SCEV *LHS,
553 /// getSCEVAtScope - Return a SCEV expression for the specified value
554 /// at the specified scope in the program. The L value specifies a loop
555 /// nest to evaluate the expression at, where null is the top-level or a
556 /// specified loop is immediately inside of the loop.
558 /// This method can be used to compute the exit value for a variable defined
559 /// in a loop by querying what the value will hold in the parent loop.
561 /// In the case that a relevant loop exit value cannot be computed, the
562 /// original value V is returned.
563 const SCEV *getSCEVAtScope(const SCEV *S, const Loop *L);
565 /// getSCEVAtScope - This is a convenience function which does
566 /// getSCEVAtScope(getSCEV(V), L).
567 const SCEV *getSCEVAtScope(Value *V, const Loop *L);
569 /// isLoopEntryGuardedByCond - Test whether entry to the loop is protected
570 /// by a conditional between LHS and RHS. This is used to help avoid max
571 /// expressions in loop trip counts, and to eliminate casts.
572 bool isLoopEntryGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
573 const SCEV *LHS, const SCEV *RHS);
575 /// isLoopBackedgeGuardedByCond - Test whether the backedge of the loop is
576 /// protected by a conditional between LHS and RHS. This is used to
577 /// to eliminate casts.
578 bool isLoopBackedgeGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
579 const SCEV *LHS, const SCEV *RHS);
581 /// getBackedgeTakenCount - If the specified loop has a predictable
582 /// backedge-taken count, return it, otherwise return a SCEVCouldNotCompute
583 /// object. The backedge-taken count is the number of times the loop header
584 /// will be branched to from within the loop. This is one less than the
585 /// trip count of the loop, since it doesn't count the first iteration,
586 /// when the header is branched to from outside the loop.
588 /// Note that it is not valid to call this method on a loop without a
589 /// loop-invariant backedge-taken count (see
590 /// hasLoopInvariantBackedgeTakenCount).
592 const SCEV *getBackedgeTakenCount(const Loop *L);
594 /// getMaxBackedgeTakenCount - Similar to getBackedgeTakenCount, except
595 /// return the least SCEV value that is known never to be less than the
596 /// actual backedge taken count.
597 const SCEV *getMaxBackedgeTakenCount(const Loop *L);
599 /// hasLoopInvariantBackedgeTakenCount - Return true if the specified loop
600 /// has an analyzable loop-invariant backedge-taken count.
601 bool hasLoopInvariantBackedgeTakenCount(const Loop *L);
603 /// forgetLoop - This method should be called by the client when it has
604 /// changed a loop in a way that may effect ScalarEvolution's ability to
605 /// compute a trip count, or if the loop is deleted.
606 void forgetLoop(const Loop *L);
608 /// forgetValue - This method should be called by the client when it has
609 /// changed a value in a way that may effect its value, or which may
610 /// disconnect it from a def-use chain linking it to a loop.
611 void forgetValue(Value *V);
613 /// GetMinTrailingZeros - Determine the minimum number of zero bits that S
614 /// is guaranteed to end in (at every loop iteration). It is, at the same
615 /// time, the minimum number of times S is divisible by 2. For example,
616 /// given {4,+,8} it returns 2. If S is guaranteed to be 0, it returns the
618 uint32_t GetMinTrailingZeros(const SCEV *S);
620 /// getUnsignedRange - Determine the unsigned range for a particular SCEV.
622 ConstantRange getUnsignedRange(const SCEV *S);
624 /// getSignedRange - Determine the signed range for a particular SCEV.
626 ConstantRange getSignedRange(const SCEV *S);
628 /// isKnownNegative - Test if the given expression is known to be negative.
630 bool isKnownNegative(const SCEV *S);
632 /// isKnownPositive - Test if the given expression is known to be positive.
634 bool isKnownPositive(const SCEV *S);
636 /// isKnownNonNegative - Test if the given expression is known to be
639 bool isKnownNonNegative(const SCEV *S);
641 /// isKnownNonPositive - Test if the given expression is known to be
644 bool isKnownNonPositive(const SCEV *S);
646 /// isKnownNonZero - Test if the given expression is known to be
649 bool isKnownNonZero(const SCEV *S);
651 /// isKnownPredicate - Test if the given expression is known to satisfy
652 /// the condition described by Pred, LHS, and RHS.
654 bool isKnownPredicate(ICmpInst::Predicate Pred,
655 const SCEV *LHS, const SCEV *RHS);
657 /// SimplifyICmpOperands - Simplify LHS and RHS in a comparison with
658 /// predicate Pred. Return true iff any changes were made. If the
659 /// operands are provably equal or inequal, LHS and RHS are set to
660 /// the same value and Pred is set to either ICMP_EQ or ICMP_NE.
662 bool SimplifyICmpOperands(ICmpInst::Predicate &Pred,
666 /// isLoopInvariant - Return true if the value of the given SCEV is
667 /// unchanging in the specified loop.
668 bool isLoopInvariant(const SCEV *S, const Loop *L);
670 /// hasComputableLoopEvolution - Return true if the given SCEV changes value
671 /// in a known way in the specified loop. This property being true implies
672 /// that the value is variant in the loop AND that we can emit an expression
673 /// to compute the value of the expression at any particular loop iteration.
674 bool hasComputableLoopEvolution(const SCEV *S, const Loop *L);
676 /// dominates - Return true if elements that makes up the given SCEV
677 /// dominate the specified basic block.
678 bool dominates(const SCEV *S, BasicBlock *BB) const;
680 /// properlyDominates - Return true if elements that makes up the given SCEV
681 /// properly dominate the specified basic block.
682 bool properlyDominates(const SCEV *S, BasicBlock *BB) const;
684 /// hasOperand - Test whether the given SCEV has Op as a direct or
685 /// indirect operand.
686 bool hasOperand(const SCEV *S, const SCEV *Op) const;
688 virtual bool runOnFunction(Function &F);
689 virtual void releaseMemory();
690 virtual void getAnalysisUsage(AnalysisUsage &AU) const;
691 virtual void print(raw_ostream &OS, const Module* = 0) const;
694 FoldingSet<SCEV> UniqueSCEVs;
695 BumpPtrAllocator SCEVAllocator;
697 /// FirstUnknown - The head of a linked list of all SCEVUnknown
698 /// values that have been allocated. This is used by releaseMemory
699 /// to locate them all and call their destructors.
700 SCEVUnknown *FirstUnknown;