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;
48 /// SCEV - This class represents an analyzed expression in the program. These
49 /// are opaque objects that the client is not allowed to do much with
52 class SCEV : public FoldingSetNode {
53 /// FastID - A reference to an Interned FoldingSetNodeID for this node.
54 /// The ScalarEvolution's BumpPtrAllocator holds the data.
55 FoldingSetNodeIDRef FastID;
57 // The SCEV baseclass this node corresponds to
58 const unsigned short SCEVType;
61 /// SubclassData - This field is initialized to zero and may be used in
62 /// subclasses to store miscellaneous information.
63 unsigned short SubclassData;
66 SCEV(const SCEV &); // DO NOT IMPLEMENT
67 void operator=(const SCEV &); // DO NOT IMPLEMENT
71 explicit SCEV(const FoldingSetNodeIDRef ID, unsigned SCEVTy) :
72 FastID(ID), SCEVType(SCEVTy), SubclassData(0) {}
74 unsigned getSCEVType() const { return SCEVType; }
76 /// Profile - FoldingSet support.
77 void Profile(FoldingSetNodeID& ID) { ID = FastID; }
79 /// isLoopInvariant - Return true if the value of this SCEV is unchanging in
80 /// the specified loop.
81 virtual bool isLoopInvariant(const Loop *L) const = 0;
83 /// hasComputableLoopEvolution - Return true if this SCEV changes value in a
84 /// known way in the specified loop. This property being true implies that
85 /// the value is variant in the loop AND that we can emit an expression to
86 /// compute the value of the expression at any particular loop iteration.
87 virtual bool hasComputableLoopEvolution(const Loop *L) const = 0;
89 /// getType - Return the LLVM type of this SCEV expression.
91 virtual const Type *getType() const = 0;
93 /// isZero - Return true if the expression is a constant zero.
97 /// isOne - Return true if the expression is a constant one.
101 /// isAllOnesValue - Return true if the expression is a constant
104 bool isAllOnesValue() const;
106 /// hasOperand - Test whether this SCEV has Op as a direct or
107 /// indirect operand.
108 virtual bool hasOperand(const SCEV *Op) const = 0;
110 /// dominates - Return true if elements that makes up this SCEV dominates
111 /// the specified basic block.
112 virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const = 0;
114 /// properlyDominates - Return true if elements that makes up this SCEV
115 /// properly dominate the specified basic block.
116 virtual bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const = 0;
118 /// print - Print out the internal representation of this scalar to the
119 /// specified stream. This should really only be used for debugging
121 virtual void print(raw_ostream &OS) const = 0;
123 /// dump - This method is used for debugging.
128 inline raw_ostream &operator<<(raw_ostream &OS, const SCEV &S) {
133 /// SCEVCouldNotCompute - An object of this class is returned by queries that
134 /// could not be answered. For example, if you ask for the number of
135 /// iterations of a linked-list traversal loop, you will get one of these.
136 /// None of the standard SCEV operations are valid on this class, it is just a
138 struct SCEVCouldNotCompute : public SCEV {
139 SCEVCouldNotCompute();
141 // None of these methods are valid for this object.
142 virtual bool isLoopInvariant(const Loop *L) const;
143 virtual const Type *getType() const;
144 virtual bool hasComputableLoopEvolution(const Loop *L) const;
145 virtual void print(raw_ostream &OS) const;
146 virtual bool hasOperand(const SCEV *Op) const;
148 virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const {
152 virtual bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
156 /// Methods for support type inquiry through isa, cast, and dyn_cast:
157 static inline bool classof(const SCEVCouldNotCompute *S) { return true; }
158 static bool classof(const SCEV *S);
161 /// ScalarEvolution - This class is the main scalar evolution driver. Because
162 /// client code (intentionally) can't do much with the SCEV objects directly,
163 /// they must ask this class for services.
165 class ScalarEvolution : public FunctionPass {
166 /// SCEVCallbackVH - A CallbackVH to arrange for ScalarEvolution to be
167 /// notified whenever a Value is deleted.
168 class SCEVCallbackVH : public CallbackVH {
170 virtual void deleted();
171 virtual void allUsesReplacedWith(Value *New);
173 SCEVCallbackVH(Value *V, ScalarEvolution *SE = 0);
176 friend class SCEVCallbackVH;
177 friend class SCEVExpander;
179 /// F - The function we are analyzing.
183 /// LI - The loop information for the function we are currently analyzing.
187 /// TD - The target data information for the target we are targeting.
191 /// DT - The dominator tree.
195 /// CouldNotCompute - This SCEV is used to represent unknown trip
196 /// counts and things.
197 SCEVCouldNotCompute CouldNotCompute;
199 /// Scalars - This is a cache of the scalars we have analyzed so far.
201 std::map<SCEVCallbackVH, const SCEV *> Scalars;
203 /// BackedgeTakenInfo - Information about the backedge-taken count
204 /// of a loop. This currently includes an exact count and a maximum count.
206 struct BackedgeTakenInfo {
207 /// Exact - An expression indicating the exact backedge-taken count of
208 /// the loop if it is known, or a SCEVCouldNotCompute otherwise.
211 /// Max - An expression indicating the least maximum backedge-taken
212 /// count of the loop that is known, or a SCEVCouldNotCompute.
215 /*implicit*/ BackedgeTakenInfo(const SCEV *exact) :
216 Exact(exact), Max(exact) {}
218 BackedgeTakenInfo(const SCEV *exact, const SCEV *max) :
219 Exact(exact), Max(max) {}
221 /// hasAnyInfo - Test whether this BackedgeTakenInfo contains any
222 /// computed information, or whether it's all SCEVCouldNotCompute
224 bool hasAnyInfo() const {
225 return !isa<SCEVCouldNotCompute>(Exact) ||
226 !isa<SCEVCouldNotCompute>(Max);
230 /// BackedgeTakenCounts - Cache the backedge-taken count of the loops for
231 /// this function as they are computed.
232 std::map<const Loop*, BackedgeTakenInfo> BackedgeTakenCounts;
234 /// ConstantEvolutionLoopExitValue - This map contains entries for all of
235 /// the PHI instructions that we attempt to compute constant evolutions for.
236 /// This allows us to avoid potentially expensive recomputation of these
237 /// properties. An instruction maps to null if we are unable to compute its
239 std::map<PHINode*, Constant*> ConstantEvolutionLoopExitValue;
241 /// ValuesAtScopes - This map contains entries for all the expressions
242 /// that we attempt to compute getSCEVAtScope information for, which can
243 /// be expensive in extreme cases.
244 std::map<const SCEV *,
245 std::map<const Loop *, const SCEV *> > ValuesAtScopes;
247 /// createSCEV - We know that there is no SCEV for the specified value.
248 /// Analyze the expression.
249 const SCEV *createSCEV(Value *V);
251 /// createNodeForPHI - Provide the special handling we need to analyze PHI
253 const SCEV *createNodeForPHI(PHINode *PN);
255 /// createNodeForGEP - Provide the special handling we need to analyze GEP
257 const SCEV *createNodeForGEP(GEPOperator *GEP);
259 /// computeSCEVAtScope - Implementation code for getSCEVAtScope; called
260 /// at most once for each SCEV+Loop pair.
262 const SCEV *computeSCEVAtScope(const SCEV *S, const Loop *L);
264 /// ForgetSymbolicValue - This looks up computed SCEV values for all
265 /// instructions that depend on the given instruction and removes them from
266 /// the Scalars map if they reference SymName. This is used during PHI
268 void ForgetSymbolicName(Instruction *I, const SCEV *SymName);
270 /// getBECount - Subtract the end and start values and divide by the step,
271 /// rounding up, to get the number of times the backedge is executed. Return
272 /// CouldNotCompute if an intermediate computation overflows.
273 const SCEV *getBECount(const SCEV *Start,
278 /// getBackedgeTakenInfo - Return the BackedgeTakenInfo for the given
279 /// loop, lazily computing new values if the loop hasn't been analyzed
281 const BackedgeTakenInfo &getBackedgeTakenInfo(const Loop *L);
283 /// ComputeBackedgeTakenCount - Compute the number of times the specified
284 /// loop will iterate.
285 BackedgeTakenInfo ComputeBackedgeTakenCount(const Loop *L);
287 /// ComputeBackedgeTakenCountFromExit - Compute the number of times the
288 /// backedge of the specified loop will execute if it exits via the
290 BackedgeTakenInfo ComputeBackedgeTakenCountFromExit(const Loop *L,
291 BasicBlock *ExitingBlock);
293 /// ComputeBackedgeTakenCountFromExitCond - Compute the number of times the
294 /// backedge of the specified loop will execute if its exit condition
295 /// were a conditional branch of ExitCond, TBB, and FBB.
297 ComputeBackedgeTakenCountFromExitCond(const Loop *L,
302 /// ComputeBackedgeTakenCountFromExitCondICmp - Compute the number of
303 /// times the backedge of the specified loop will execute if its exit
304 /// condition were a conditional branch of the ICmpInst ExitCond, TBB,
307 ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L,
312 /// ComputeLoadConstantCompareBackedgeTakenCount - Given an exit condition
313 /// of 'icmp op load X, cst', try to see if we can compute the
314 /// backedge-taken count.
316 ComputeLoadConstantCompareBackedgeTakenCount(LoadInst *LI,
319 ICmpInst::Predicate p);
321 /// ComputeBackedgeTakenCountExhaustively - If the loop is known to execute
322 /// a constant number of times (the condition evolves only from constants),
323 /// try to evaluate a few iterations of the loop until we get the exit
324 /// condition gets a value of ExitWhen (true or false). If we cannot
325 /// evaluate the backedge-taken count of the loop, return CouldNotCompute.
326 const SCEV *ComputeBackedgeTakenCountExhaustively(const Loop *L,
330 /// HowFarToZero - Return the number of times a backedge comparing the
331 /// specified value to zero will execute. If not computable, return
333 BackedgeTakenInfo HowFarToZero(const SCEV *V, const Loop *L);
335 /// HowFarToNonZero - Return the number of times a backedge checking the
336 /// specified value for nonzero will execute. If not computable, return
338 BackedgeTakenInfo HowFarToNonZero(const SCEV *V, const Loop *L);
340 /// HowManyLessThans - Return the number of times a backedge containing the
341 /// specified less-than comparison will execute. If not computable, return
342 /// CouldNotCompute. isSigned specifies whether the less-than is signed.
343 BackedgeTakenInfo HowManyLessThans(const SCEV *LHS, const SCEV *RHS,
344 const Loop *L, bool isSigned);
346 /// getLoopPredecessor - If the given loop's header has exactly one unique
347 /// predecessor outside the loop, return it. Otherwise return null.
348 BasicBlock *getLoopPredecessor(const Loop *L);
350 /// getPredecessorWithUniqueSuccessorForBB - Return a predecessor of BB
351 /// (which may not be an immediate predecessor) which has exactly one
352 /// successor from which BB is reachable, or null if no such block is
354 std::pair<BasicBlock *, BasicBlock *>
355 getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB);
357 /// isImpliedCond - Test whether the condition described by Pred, LHS,
358 /// and RHS is true whenever the given Cond value evaluates to true.
359 bool isImpliedCond(Value *Cond, ICmpInst::Predicate Pred,
360 const SCEV *LHS, const SCEV *RHS,
363 /// isImpliedCondOperands - Test whether the condition described by Pred,
364 /// LHS, and RHS is true whenever the condition described by Pred, FoundLHS,
365 /// and FoundRHS is true.
366 bool isImpliedCondOperands(ICmpInst::Predicate Pred,
367 const SCEV *LHS, const SCEV *RHS,
368 const SCEV *FoundLHS, const SCEV *FoundRHS);
370 /// isImpliedCondOperandsHelper - Test whether the condition described by
371 /// Pred, LHS, and RHS is true whenever the condition described by Pred,
372 /// FoundLHS, and FoundRHS is true.
373 bool isImpliedCondOperandsHelper(ICmpInst::Predicate Pred,
374 const SCEV *LHS, const SCEV *RHS,
375 const SCEV *FoundLHS, const SCEV *FoundRHS);
377 /// getConstantEvolutionLoopExitValue - If we know that the specified Phi is
378 /// in the header of its containing loop, we know the loop executes a
379 /// constant number of times, and the PHI node is just a recurrence
380 /// involving constants, fold it.
381 Constant *getConstantEvolutionLoopExitValue(PHINode *PN, const APInt& BEs,
384 /// isKnownPredicateWithRanges - Test if the given expression is known to
385 /// satisfy the condition described by Pred and the known constant ranges
388 bool isKnownPredicateWithRanges(ICmpInst::Predicate Pred,
389 const SCEV *LHS, const SCEV *RHS);
392 static char ID; // Pass identification, replacement for typeid
395 LLVMContext &getContext() const { return F->getContext(); }
397 /// isSCEVable - Test if values of the given type are analyzable within
398 /// the SCEV framework. This primarily includes integer types, and it
399 /// can optionally include pointer types if the ScalarEvolution class
400 /// has access to target-specific information.
401 bool isSCEVable(const Type *Ty) const;
403 /// getTypeSizeInBits - Return the size in bits of the specified type,
404 /// for which isSCEVable must return true.
405 uint64_t getTypeSizeInBits(const Type *Ty) const;
407 /// getEffectiveSCEVType - Return a type with the same bitwidth as
408 /// the given type and which represents how SCEV will treat the given
409 /// type, for which isSCEVable must return true. For pointer types,
410 /// this is the pointer-sized integer type.
411 const Type *getEffectiveSCEVType(const Type *Ty) const;
413 /// getSCEV - Return a SCEV expression for the full generality of the
414 /// specified expression.
415 const SCEV *getSCEV(Value *V);
417 const SCEV *getConstant(ConstantInt *V);
418 const SCEV *getConstant(const APInt& Val);
419 const SCEV *getConstant(const Type *Ty, uint64_t V, bool isSigned = false);
420 const SCEV *getTruncateExpr(const SCEV *Op, const Type *Ty);
421 const SCEV *getZeroExtendExpr(const SCEV *Op, const Type *Ty);
422 const SCEV *getSignExtendExpr(const SCEV *Op, const Type *Ty);
423 const SCEV *getAnyExtendExpr(const SCEV *Op, const Type *Ty);
424 const SCEV *getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
425 bool HasNUW = false, bool HasNSW = false);
426 const SCEV *getAddExpr(const SCEV *LHS, const SCEV *RHS,
427 bool HasNUW = false, bool HasNSW = false) {
428 SmallVector<const SCEV *, 2> Ops;
431 return getAddExpr(Ops, HasNUW, HasNSW);
433 const SCEV *getAddExpr(const SCEV *Op0, const SCEV *Op1,
435 bool HasNUW = false, bool HasNSW = false) {
436 SmallVector<const SCEV *, 3> Ops;
440 return getAddExpr(Ops, HasNUW, HasNSW);
442 const SCEV *getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
443 bool HasNUW = false, bool HasNSW = false);
444 const SCEV *getMulExpr(const SCEV *LHS, const SCEV *RHS,
445 bool HasNUW = false, bool HasNSW = false) {
446 SmallVector<const SCEV *, 2> Ops;
449 return getMulExpr(Ops, HasNUW, HasNSW);
451 const SCEV *getUDivExpr(const SCEV *LHS, const SCEV *RHS);
452 const SCEV *getAddRecExpr(const SCEV *Start, const SCEV *Step,
454 bool HasNUW = false, bool HasNSW = false);
455 const SCEV *getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
457 bool HasNUW = false, bool HasNSW = false);
458 const SCEV *getAddRecExpr(const SmallVectorImpl<const SCEV *> &Operands,
460 bool HasNUW = false, bool HasNSW = false) {
461 SmallVector<const SCEV *, 4> NewOp(Operands.begin(), Operands.end());
462 return getAddRecExpr(NewOp, L, HasNUW, HasNSW);
464 const SCEV *getSMaxExpr(const SCEV *LHS, const SCEV *RHS);
465 const SCEV *getSMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
466 const SCEV *getUMaxExpr(const SCEV *LHS, const SCEV *RHS);
467 const SCEV *getUMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
468 const SCEV *getSMinExpr(const SCEV *LHS, const SCEV *RHS);
469 const SCEV *getUMinExpr(const SCEV *LHS, const SCEV *RHS);
470 const SCEV *getUnknown(Value *V);
471 const SCEV *getCouldNotCompute();
473 /// getSizeOfExpr - Return an expression for sizeof on the given type.
475 const SCEV *getSizeOfExpr(const Type *AllocTy);
477 /// getAlignOfExpr - Return an expression for alignof on the given type.
479 const SCEV *getAlignOfExpr(const Type *AllocTy);
481 /// getOffsetOfExpr - Return an expression for offsetof on the given field.
483 const SCEV *getOffsetOfExpr(const StructType *STy, unsigned FieldNo);
485 /// getOffsetOfExpr - Return an expression for offsetof on the given field.
487 const SCEV *getOffsetOfExpr(const Type *CTy, Constant *FieldNo);
489 /// getNegativeSCEV - Return the SCEV object corresponding to -V.
491 const SCEV *getNegativeSCEV(const SCEV *V);
493 /// getNotSCEV - Return the SCEV object corresponding to ~V.
495 const SCEV *getNotSCEV(const SCEV *V);
497 /// getMinusSCEV - Return LHS-RHS.
499 const SCEV *getMinusSCEV(const SCEV *LHS,
502 /// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
503 /// of the input value to the specified type. If the type must be
504 /// extended, it is zero extended.
505 const SCEV *getTruncateOrZeroExtend(const SCEV *V, const Type *Ty);
507 /// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion
508 /// of the input value to the specified type. If the type must be
509 /// extended, it is sign extended.
510 const SCEV *getTruncateOrSignExtend(const SCEV *V, const Type *Ty);
512 /// getNoopOrZeroExtend - Return a SCEV corresponding to a conversion of
513 /// the input value to the specified type. If the type must be extended,
514 /// it is zero extended. The conversion must not be narrowing.
515 const SCEV *getNoopOrZeroExtend(const SCEV *V, const Type *Ty);
517 /// getNoopOrSignExtend - Return a SCEV corresponding to a conversion of
518 /// the input value to the specified type. If the type must be extended,
519 /// it is sign extended. The conversion must not be narrowing.
520 const SCEV *getNoopOrSignExtend(const SCEV *V, const Type *Ty);
522 /// getNoopOrAnyExtend - Return a SCEV corresponding to a conversion of
523 /// the input value to the specified type. If the type must be extended,
524 /// it is extended with unspecified bits. The conversion must not be
526 const SCEV *getNoopOrAnyExtend(const SCEV *V, const Type *Ty);
528 /// getTruncateOrNoop - Return a SCEV corresponding to a conversion of the
529 /// input value to the specified type. The conversion must not be
531 const SCEV *getTruncateOrNoop(const SCEV *V, const Type *Ty);
533 /// getUMaxFromMismatchedTypes - Promote the operands to the wider of
534 /// the types using zero-extension, and then perform a umax operation
536 const SCEV *getUMaxFromMismatchedTypes(const SCEV *LHS,
539 /// getUMinFromMismatchedTypes - Promote the operands to the wider of
540 /// the types using zero-extension, and then perform a umin operation
542 const SCEV *getUMinFromMismatchedTypes(const SCEV *LHS,
545 /// getSCEVAtScope - Return a SCEV expression for the specified value
546 /// at the specified scope in the program. The L value specifies a loop
547 /// nest to evaluate the expression at, where null is the top-level or a
548 /// specified loop is immediately inside of the loop.
550 /// This method can be used to compute the exit value for a variable defined
551 /// in a loop by querying what the value will hold in the parent loop.
553 /// In the case that a relevant loop exit value cannot be computed, the
554 /// original value V is returned.
555 const SCEV *getSCEVAtScope(const SCEV *S, const Loop *L);
557 /// getSCEVAtScope - This is a convenience function which does
558 /// getSCEVAtScope(getSCEV(V), L).
559 const SCEV *getSCEVAtScope(Value *V, const Loop *L);
561 /// isLoopEntryGuardedByCond - Test whether entry to the loop is protected
562 /// by a conditional between LHS and RHS. This is used to help avoid max
563 /// expressions in loop trip counts, and to eliminate casts.
564 bool isLoopEntryGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
565 const SCEV *LHS, const SCEV *RHS);
567 /// isLoopBackedgeGuardedByCond - Test whether the backedge of the loop is
568 /// protected by a conditional between LHS and RHS. This is used to
569 /// to eliminate casts.
570 bool isLoopBackedgeGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
571 const SCEV *LHS, const SCEV *RHS);
573 /// getBackedgeTakenCount - If the specified loop has a predictable
574 /// backedge-taken count, return it, otherwise return a SCEVCouldNotCompute
575 /// object. The backedge-taken count is the number of times the loop header
576 /// will be branched to from within the loop. This is one less than the
577 /// trip count of the loop, since it doesn't count the first iteration,
578 /// when the header is branched to from outside the loop.
580 /// Note that it is not valid to call this method on a loop without a
581 /// loop-invariant backedge-taken count (see
582 /// hasLoopInvariantBackedgeTakenCount).
584 const SCEV *getBackedgeTakenCount(const Loop *L);
586 /// getMaxBackedgeTakenCount - Similar to getBackedgeTakenCount, except
587 /// return the least SCEV value that is known never to be less than the
588 /// actual backedge taken count.
589 const SCEV *getMaxBackedgeTakenCount(const Loop *L);
591 /// hasLoopInvariantBackedgeTakenCount - Return true if the specified loop
592 /// has an analyzable loop-invariant backedge-taken count.
593 bool hasLoopInvariantBackedgeTakenCount(const Loop *L);
595 /// forgetLoop - This method should be called by the client when it has
596 /// changed a loop in a way that may effect ScalarEvolution's ability to
597 /// compute a trip count, or if the loop is deleted.
598 void forgetLoop(const Loop *L);
600 /// forgetValue - This method should be called by the client when it has
601 /// changed a value in a way that may effect its value, or which may
602 /// disconnect it from a def-use chain linking it to a loop.
603 void forgetValue(Value *V);
605 /// GetMinTrailingZeros - Determine the minimum number of zero bits that S
606 /// is guaranteed to end in (at every loop iteration). It is, at the same
607 /// time, the minimum number of times S is divisible by 2. For example,
608 /// given {4,+,8} it returns 2. If S is guaranteed to be 0, it returns the
610 uint32_t GetMinTrailingZeros(const SCEV *S);
612 /// getUnsignedRange - Determine the unsigned range for a particular SCEV.
614 ConstantRange getUnsignedRange(const SCEV *S);
616 /// getSignedRange - Determine the signed range for a particular SCEV.
618 ConstantRange getSignedRange(const SCEV *S);
620 /// isKnownNegative - Test if the given expression is known to be negative.
622 bool isKnownNegative(const SCEV *S);
624 /// isKnownPositive - Test if the given expression is known to be positive.
626 bool isKnownPositive(const SCEV *S);
628 /// isKnownNonNegative - Test if the given expression is known to be
631 bool isKnownNonNegative(const SCEV *S);
633 /// isKnownNonPositive - Test if the given expression is known to be
636 bool isKnownNonPositive(const SCEV *S);
638 /// isKnownNonZero - Test if the given expression is known to be
641 bool isKnownNonZero(const SCEV *S);
643 /// isKnownPredicate - Test if the given expression is known to satisfy
644 /// the condition described by Pred, LHS, and RHS.
646 bool isKnownPredicate(ICmpInst::Predicate Pred,
647 const SCEV *LHS, const SCEV *RHS);
649 /// SimplifyICmpOperands - Simplify LHS and RHS in a comparison with
650 /// predicate Pred. Return true iff any changes were made. If the
651 /// operands are provably equal or inequal, LHS and RHS are set to
652 /// the same value and Pred is set to either ICMP_EQ or ICMP_NE.
654 bool SimplifyICmpOperands(ICmpInst::Predicate &Pred,
658 virtual bool runOnFunction(Function &F);
659 virtual void releaseMemory();
660 virtual void getAnalysisUsage(AnalysisUsage &AU) const;
661 virtual void print(raw_ostream &OS, const Module* = 0) const;
664 FoldingSet<SCEV> UniqueSCEVs;
665 BumpPtrAllocator SCEVAllocator;