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 FastFoldingSetNode {
53 // The SCEV baseclass this node corresponds to
54 const unsigned short SCEVType;
57 /// SubclassData - This field is initialized to zero and may be used in
58 /// subclasses to store miscellaneous information.
59 unsigned short SubclassData;
62 SCEV(const SCEV &); // DO NOT IMPLEMENT
63 void operator=(const SCEV &); // DO NOT IMPLEMENT
67 explicit SCEV(const FoldingSetNodeID &ID, unsigned SCEVTy) :
68 FastFoldingSetNode(ID), SCEVType(SCEVTy), SubclassData(0) {}
70 unsigned getSCEVType() const { return SCEVType; }
72 /// isLoopInvariant - Return true if the value of this SCEV is unchanging in
73 /// the specified loop.
74 virtual bool isLoopInvariant(const Loop *L) const = 0;
76 /// hasComputableLoopEvolution - Return true if this SCEV changes value in a
77 /// known way in the specified loop. This property being true implies that
78 /// the value is variant in the loop AND that we can emit an expression to
79 /// compute the value of the expression at any particular loop iteration.
80 virtual bool hasComputableLoopEvolution(const Loop *L) const = 0;
82 /// getType - Return the LLVM type of this SCEV expression.
84 virtual const Type *getType() const = 0;
86 /// isZero - Return true if the expression is a constant zero.
90 /// isOne - Return true if the expression is a constant one.
94 /// isAllOnesValue - Return true if the expression is a constant
97 bool isAllOnesValue() const;
99 /// hasOperand - Test whether this SCEV has Op as a direct or
100 /// indirect operand.
101 virtual bool hasOperand(const SCEV *Op) const = 0;
103 /// dominates - Return true if elements that makes up this SCEV dominates
104 /// the specified basic block.
105 virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const = 0;
107 /// properlyDominates - Return true if elements that makes up this SCEV
108 /// properly dominate the specified basic block.
109 virtual bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const = 0;
111 /// print - Print out the internal representation of this scalar to the
112 /// specified stream. This should really only be used for debugging
114 virtual void print(raw_ostream &OS) const = 0;
116 /// dump - This method is used for debugging.
121 inline raw_ostream &operator<<(raw_ostream &OS, const SCEV &S) {
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
131 struct SCEVCouldNotCompute : public SCEV {
132 SCEVCouldNotCompute();
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 bool hasOperand(const SCEV *Op) const;
141 virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const {
145 virtual bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
149 /// Methods for support type inquiry through isa, cast, and dyn_cast:
150 static inline bool classof(const SCEVCouldNotCompute *S) { return true; }
151 static bool classof(const SCEV *S);
154 /// ScalarEvolution - This class is the main scalar evolution driver. Because
155 /// client code (intentionally) can't do much with the SCEV objects directly,
156 /// they must ask this class for services.
158 class ScalarEvolution : public FunctionPass {
159 /// SCEVCallbackVH - A CallbackVH to arrange for ScalarEvolution to be
160 /// notified whenever a Value is deleted.
161 class SCEVCallbackVH : public CallbackVH {
163 virtual void deleted();
164 virtual void allUsesReplacedWith(Value *New);
166 SCEVCallbackVH(Value *V, ScalarEvolution *SE = 0);
169 friend class SCEVCallbackVH;
170 friend class SCEVExpander;
172 /// F - The function we are analyzing.
176 /// LI - The loop information for the function we are currently analyzing.
180 /// TD - The target data information for the target we are targeting.
184 /// DT - The dominator tree.
188 /// CouldNotCompute - This SCEV is used to represent unknown trip
189 /// counts and things.
190 SCEVCouldNotCompute CouldNotCompute;
192 /// Scalars - This is a cache of the scalars we have analyzed so far.
194 std::map<SCEVCallbackVH, const SCEV *> Scalars;
196 /// BackedgeTakenInfo - Information about the backedge-taken count
197 /// of a loop. This currently includes an exact count and a maximum count.
199 struct BackedgeTakenInfo {
200 /// Exact - An expression indicating the exact backedge-taken count of
201 /// the loop if it is known, or a SCEVCouldNotCompute otherwise.
204 /// Max - An expression indicating the least maximum backedge-taken
205 /// count of the loop that is known, or a SCEVCouldNotCompute.
208 /*implicit*/ BackedgeTakenInfo(const SCEV *exact) :
209 Exact(exact), Max(exact) {}
211 BackedgeTakenInfo(const SCEV *exact, const SCEV *max) :
212 Exact(exact), Max(max) {}
214 /// hasAnyInfo - Test whether this BackedgeTakenInfo contains any
215 /// computed information, or whether it's all SCEVCouldNotCompute
217 bool hasAnyInfo() const {
218 return !isa<SCEVCouldNotCompute>(Exact) ||
219 !isa<SCEVCouldNotCompute>(Max);
223 /// BackedgeTakenCounts - Cache the backedge-taken count of the loops for
224 /// this function as they are computed.
225 std::map<const Loop*, BackedgeTakenInfo> BackedgeTakenCounts;
227 /// ConstantEvolutionLoopExitValue - This map contains entries for all of
228 /// the PHI instructions that we attempt to compute constant evolutions for.
229 /// This allows us to avoid potentially expensive recomputation of these
230 /// properties. An instruction maps to null if we are unable to compute its
232 std::map<PHINode*, Constant*> ConstantEvolutionLoopExitValue;
234 /// ValuesAtScopes - This map contains entries for all the expressions
235 /// that we attempt to compute getSCEVAtScope information for, which can
236 /// be expensive in extreme cases.
237 std::map<const SCEV *,
238 std::map<const Loop *, const SCEV *> > ValuesAtScopes;
240 /// createSCEV - We know that there is no SCEV for the specified value.
241 /// Analyze the expression.
242 const SCEV *createSCEV(Value *V);
244 /// createNodeForPHI - Provide the special handling we need to analyze PHI
246 const SCEV *createNodeForPHI(PHINode *PN);
248 /// createNodeForGEP - Provide the special handling we need to analyze GEP
250 const SCEV *createNodeForGEP(GEPOperator *GEP);
252 /// computeSCEVAtScope - Implementation code for getSCEVAtScope; called
253 /// at most once for each SCEV+Loop pair.
255 const SCEV *computeSCEVAtScope(const SCEV *S, const Loop *L);
257 /// ForgetSymbolicValue - This looks up computed SCEV values for all
258 /// instructions that depend on the given instruction and removes them from
259 /// the Scalars map if they reference SymName. This is used during PHI
261 void ForgetSymbolicName(Instruction *I, const SCEV *SymName);
263 /// getBECount - Subtract the end and start values and divide by the step,
264 /// rounding up, to get the number of times the backedge is executed. Return
265 /// CouldNotCompute if an intermediate computation overflows.
266 const SCEV *getBECount(const SCEV *Start,
271 /// getBackedgeTakenInfo - Return the BackedgeTakenInfo for the given
272 /// loop, lazily computing new values if the loop hasn't been analyzed
274 const BackedgeTakenInfo &getBackedgeTakenInfo(const Loop *L);
276 /// ComputeBackedgeTakenCount - Compute the number of times the specified
277 /// loop will iterate.
278 BackedgeTakenInfo ComputeBackedgeTakenCount(const Loop *L);
280 /// ComputeBackedgeTakenCountFromExit - Compute the number of times the
281 /// backedge of the specified loop will execute if it exits via the
283 BackedgeTakenInfo ComputeBackedgeTakenCountFromExit(const Loop *L,
284 BasicBlock *ExitingBlock);
286 /// ComputeBackedgeTakenCountFromExitCond - Compute the number of times the
287 /// backedge of the specified loop will execute if its exit condition
288 /// were a conditional branch of ExitCond, TBB, and FBB.
290 ComputeBackedgeTakenCountFromExitCond(const Loop *L,
295 /// ComputeBackedgeTakenCountFromExitCondICmp - Compute the number of
296 /// times the backedge of the specified loop will execute if its exit
297 /// condition were a conditional branch of the ICmpInst ExitCond, TBB,
300 ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L,
305 /// ComputeLoadConstantCompareBackedgeTakenCount - Given an exit condition
306 /// of 'icmp op load X, cst', try to see if we can compute the
307 /// backedge-taken count.
309 ComputeLoadConstantCompareBackedgeTakenCount(LoadInst *LI,
312 ICmpInst::Predicate p);
314 /// ComputeBackedgeTakenCountExhaustively - If the loop is known to execute
315 /// a constant number of times (the condition evolves only from constants),
316 /// try to evaluate a few iterations of the loop until we get the exit
317 /// condition gets a value of ExitWhen (true or false). If we cannot
318 /// evaluate the backedge-taken count of the loop, return CouldNotCompute.
319 const SCEV *ComputeBackedgeTakenCountExhaustively(const Loop *L,
323 /// HowFarToZero - Return the number of times a backedge comparing the
324 /// specified value to zero will execute. If not computable, return
326 BackedgeTakenInfo HowFarToZero(const SCEV *V, const Loop *L);
328 /// HowFarToNonZero - Return the number of times a backedge checking the
329 /// specified value for nonzero will execute. If not computable, return
331 BackedgeTakenInfo HowFarToNonZero(const SCEV *V, const Loop *L);
333 /// HowManyLessThans - Return the number of times a backedge containing the
334 /// specified less-than comparison will execute. If not computable, return
335 /// CouldNotCompute. isSigned specifies whether the less-than is signed.
336 BackedgeTakenInfo HowManyLessThans(const SCEV *LHS, const SCEV *RHS,
337 const Loop *L, bool isSigned);
339 /// getLoopPredecessor - If the given loop's header has exactly one unique
340 /// predecessor outside the loop, return it. Otherwise return null.
341 BasicBlock *getLoopPredecessor(const Loop *L);
343 /// getPredecessorWithUniqueSuccessorForBB - Return a predecessor of BB
344 /// (which may not be an immediate predecessor) which has exactly one
345 /// successor from which BB is reachable, or null if no such block is
347 BasicBlock* getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB);
349 /// isImpliedCond - Test whether the condition described by Pred, LHS,
350 /// and RHS is true whenever the given Cond value evaluates to true.
351 bool isImpliedCond(Value *Cond, ICmpInst::Predicate Pred,
352 const SCEV *LHS, const SCEV *RHS,
355 /// isImpliedCondOperands - Test whether the condition described by Pred,
356 /// LHS, and RHS is true whenever the condition described by Pred, FoundLHS,
357 /// and FoundRHS is true.
358 bool isImpliedCondOperands(ICmpInst::Predicate Pred,
359 const SCEV *LHS, const SCEV *RHS,
360 const SCEV *FoundLHS, const SCEV *FoundRHS);
362 /// isImpliedCondOperandsHelper - Test whether the condition described by
363 /// Pred, LHS, and RHS is true whenever the condition described by Pred,
364 /// FoundLHS, and FoundRHS is true.
365 bool isImpliedCondOperandsHelper(ICmpInst::Predicate Pred,
366 const SCEV *LHS, const SCEV *RHS,
367 const SCEV *FoundLHS, const SCEV *FoundRHS);
369 /// getConstantEvolutionLoopExitValue - If we know that the specified Phi is
370 /// in the header of its containing loop, we know the loop executes a
371 /// constant number of times, and the PHI node is just a recurrence
372 /// involving constants, fold it.
373 Constant *getConstantEvolutionLoopExitValue(PHINode *PN, const APInt& BEs,
377 static char ID; // Pass identification, replacement for typeid
380 LLVMContext &getContext() const { return F->getContext(); }
382 /// isSCEVable - Test if values of the given type are analyzable within
383 /// the SCEV framework. This primarily includes integer types, and it
384 /// can optionally include pointer types if the ScalarEvolution class
385 /// has access to target-specific information.
386 bool isSCEVable(const Type *Ty) const;
388 /// getTypeSizeInBits - Return the size in bits of the specified type,
389 /// for which isSCEVable must return true.
390 uint64_t getTypeSizeInBits(const Type *Ty) const;
392 /// getEffectiveSCEVType - Return a type with the same bitwidth as
393 /// the given type and which represents how SCEV will treat the given
394 /// type, for which isSCEVable must return true. For pointer types,
395 /// this is the pointer-sized integer type.
396 const Type *getEffectiveSCEVType(const Type *Ty) const;
398 /// getSCEV - Return a SCEV expression for the full generality of the
399 /// specified expression.
400 const SCEV *getSCEV(Value *V);
402 const SCEV *getConstant(ConstantInt *V);
403 const SCEV *getConstant(const APInt& Val);
404 const SCEV *getConstant(const Type *Ty, uint64_t V, bool isSigned = false);
405 const SCEV *getTruncateExpr(const SCEV *Op, const Type *Ty);
406 const SCEV *getZeroExtendExpr(const SCEV *Op, const Type *Ty);
407 const SCEV *getSignExtendExpr(const SCEV *Op, const Type *Ty);
408 const SCEV *getAnyExtendExpr(const SCEV *Op, const Type *Ty);
409 const SCEV *getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
410 bool HasNUW = false, bool HasNSW = false);
411 const SCEV *getAddExpr(const SCEV *LHS, const SCEV *RHS,
412 bool HasNUW = false, bool HasNSW = false) {
413 SmallVector<const SCEV *, 2> Ops;
416 return getAddExpr(Ops, HasNUW, HasNSW);
418 const SCEV *getAddExpr(const SCEV *Op0, const SCEV *Op1,
420 bool HasNUW = false, bool HasNSW = false) {
421 SmallVector<const SCEV *, 3> Ops;
425 return getAddExpr(Ops, HasNUW, HasNSW);
427 const SCEV *getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
428 bool HasNUW = false, bool HasNSW = false);
429 const SCEV *getMulExpr(const SCEV *LHS, const SCEV *RHS,
430 bool HasNUW = false, bool HasNSW = false) {
431 SmallVector<const SCEV *, 2> Ops;
434 return getMulExpr(Ops, HasNUW, HasNSW);
436 const SCEV *getUDivExpr(const SCEV *LHS, const SCEV *RHS);
437 const SCEV *getAddRecExpr(const SCEV *Start, const SCEV *Step,
439 bool HasNUW = false, bool HasNSW = false);
440 const SCEV *getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
442 bool HasNUW = false, bool HasNSW = false);
443 const SCEV *getAddRecExpr(const SmallVectorImpl<const SCEV *> &Operands,
445 bool HasNUW = false, bool HasNSW = false) {
446 SmallVector<const SCEV *, 4> NewOp(Operands.begin(), Operands.end());
447 return getAddRecExpr(NewOp, L, HasNUW, HasNSW);
449 const SCEV *getSMaxExpr(const SCEV *LHS, const SCEV *RHS);
450 const SCEV *getSMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
451 const SCEV *getUMaxExpr(const SCEV *LHS, const SCEV *RHS);
452 const SCEV *getUMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
453 const SCEV *getSMinExpr(const SCEV *LHS, const SCEV *RHS);
454 const SCEV *getUMinExpr(const SCEV *LHS, const SCEV *RHS);
455 const SCEV *getUnknown(Value *V);
456 const SCEV *getCouldNotCompute();
458 /// getSizeOfExpr - Return an expression for sizeof on the given type.
460 const SCEV *getSizeOfExpr(const Type *AllocTy);
462 /// getAlignOfExpr - Return an expression for alignof on the given type.
464 const SCEV *getAlignOfExpr(const Type *AllocTy);
466 /// getOffsetOfExpr - Return an expression for offsetof on the given field.
468 const SCEV *getOffsetOfExpr(const StructType *STy, unsigned FieldNo);
470 /// getOffsetOfExpr - Return an expression for offsetof on the given field.
472 const SCEV *getOffsetOfExpr(const Type *CTy, Constant *FieldNo);
474 /// getNegativeSCEV - Return the SCEV object corresponding to -V.
476 const SCEV *getNegativeSCEV(const SCEV *V);
478 /// getNotSCEV - Return the SCEV object corresponding to ~V.
480 const SCEV *getNotSCEV(const SCEV *V);
482 /// getMinusSCEV - Return LHS-RHS.
484 const SCEV *getMinusSCEV(const SCEV *LHS,
487 /// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
488 /// of the input value to the specified type. If the type must be
489 /// extended, it is zero extended.
490 const SCEV *getTruncateOrZeroExtend(const SCEV *V, const Type *Ty);
492 /// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion
493 /// of the input value to the specified type. If the type must be
494 /// extended, it is sign extended.
495 const SCEV *getTruncateOrSignExtend(const SCEV *V, const Type *Ty);
497 /// getNoopOrZeroExtend - Return a SCEV corresponding to a conversion of
498 /// the input value to the specified type. If the type must be extended,
499 /// it is zero extended. The conversion must not be narrowing.
500 const SCEV *getNoopOrZeroExtend(const SCEV *V, const Type *Ty);
502 /// getNoopOrSignExtend - Return a SCEV corresponding to a conversion of
503 /// the input value to the specified type. If the type must be extended,
504 /// it is sign extended. The conversion must not be narrowing.
505 const SCEV *getNoopOrSignExtend(const SCEV *V, const Type *Ty);
507 /// getNoopOrAnyExtend - Return a SCEV corresponding to a conversion of
508 /// the input value to the specified type. If the type must be extended,
509 /// it is extended with unspecified bits. The conversion must not be
511 const SCEV *getNoopOrAnyExtend(const SCEV *V, const Type *Ty);
513 /// getTruncateOrNoop - Return a SCEV corresponding to a conversion of the
514 /// input value to the specified type. The conversion must not be
516 const SCEV *getTruncateOrNoop(const SCEV *V, const Type *Ty);
518 /// getIntegerSCEV - Given a SCEVable type, create a constant for the
519 /// specified signed integer value and return a SCEV for the constant.
520 const SCEV *getIntegerSCEV(int64_t Val, const Type *Ty);
522 /// getUMaxFromMismatchedTypes - Promote the operands to the wider of
523 /// the types using zero-extension, and then perform a umax operation
525 const SCEV *getUMaxFromMismatchedTypes(const SCEV *LHS,
528 /// getUMinFromMismatchedTypes - Promote the operands to the wider of
529 /// the types using zero-extension, and then perform a umin operation
531 const SCEV *getUMinFromMismatchedTypes(const SCEV *LHS,
534 /// getSCEVAtScope - Return a SCEV expression for the specified value
535 /// at the specified scope in the program. The L value specifies a loop
536 /// nest to evaluate the expression at, where null is the top-level or a
537 /// specified loop is immediately inside of the loop.
539 /// This method can be used to compute the exit value for a variable defined
540 /// in a loop by querying what the value will hold in the parent loop.
542 /// In the case that a relevant loop exit value cannot be computed, the
543 /// original value V is returned.
544 const SCEV *getSCEVAtScope(const SCEV *S, const Loop *L);
546 /// getSCEVAtScope - This is a convenience function which does
547 /// getSCEVAtScope(getSCEV(V), L).
548 const SCEV *getSCEVAtScope(Value *V, const Loop *L);
550 /// isLoopGuardedByCond - Test whether entry to the loop is protected by
551 /// a conditional between LHS and RHS. This is used to help avoid max
552 /// expressions in loop trip counts, and to eliminate casts.
553 bool isLoopGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
554 const SCEV *LHS, const SCEV *RHS);
556 /// isLoopBackedgeGuardedByCond - Test whether the backedge of the loop is
557 /// protected by a conditional between LHS and RHS. This is used to
558 /// to eliminate casts.
559 bool isLoopBackedgeGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
560 const SCEV *LHS, const SCEV *RHS);
562 /// getBackedgeTakenCount - If the specified loop has a predictable
563 /// backedge-taken count, return it, otherwise return a SCEVCouldNotCompute
564 /// object. The backedge-taken count is the number of times the loop header
565 /// will be branched to from within the loop. This is one less than the
566 /// trip count of the loop, since it doesn't count the first iteration,
567 /// when the header is branched to from outside the loop.
569 /// Note that it is not valid to call this method on a loop without a
570 /// loop-invariant backedge-taken count (see
571 /// hasLoopInvariantBackedgeTakenCount).
573 const SCEV *getBackedgeTakenCount(const Loop *L);
575 /// getMaxBackedgeTakenCount - Similar to getBackedgeTakenCount, except
576 /// return the least SCEV value that is known never to be less than the
577 /// actual backedge taken count.
578 const SCEV *getMaxBackedgeTakenCount(const Loop *L);
580 /// hasLoopInvariantBackedgeTakenCount - Return true if the specified loop
581 /// has an analyzable loop-invariant backedge-taken count.
582 bool hasLoopInvariantBackedgeTakenCount(const Loop *L);
584 /// forgetLoop - This method should be called by the client when it has
585 /// changed a loop in a way that may effect ScalarEvolution's ability to
586 /// compute a trip count, or if the loop is deleted.
587 void forgetLoop(const Loop *L);
589 /// forgetValue - This method should be called by the client when it has
590 /// changed a value in a way that may effect its value, or which may
591 /// disconnect it from a def-use chain linking it to a loop.
592 void forgetValue(Value *V);
594 /// GetMinTrailingZeros - Determine the minimum number of zero bits that S
595 /// is guaranteed to end in (at every loop iteration). It is, at the same
596 /// time, the minimum number of times S is divisible by 2. For example,
597 /// given {4,+,8} it returns 2. If S is guaranteed to be 0, it returns the
599 uint32_t GetMinTrailingZeros(const SCEV *S);
601 /// getUnsignedRange - Determine the unsigned range for a particular SCEV.
603 ConstantRange getUnsignedRange(const SCEV *S);
605 /// getSignedRange - Determine the signed range for a particular SCEV.
607 ConstantRange getSignedRange(const SCEV *S);
609 /// isKnownNegative - Test if the given expression is known to be negative.
611 bool isKnownNegative(const SCEV *S);
613 /// isKnownPositive - Test if the given expression is known to be positive.
615 bool isKnownPositive(const SCEV *S);
617 /// isKnownNonNegative - Test if the given expression is known to be
620 bool isKnownNonNegative(const SCEV *S);
622 /// isKnownNonPositive - Test if the given expression is known to be
625 bool isKnownNonPositive(const SCEV *S);
627 /// isKnownNonZero - Test if the given expression is known to be
630 bool isKnownNonZero(const SCEV *S);
632 /// isKnownNonZero - Test if the given expression is known to satisfy
633 /// the condition described by Pred, LHS, and RHS.
635 bool isKnownPredicate(ICmpInst::Predicate Pred,
636 const SCEV *LHS, const SCEV *RHS);
638 virtual bool runOnFunction(Function &F);
639 virtual void releaseMemory();
640 virtual void getAnalysisUsage(AnalysisUsage &AU) const;
641 virtual void print(raw_ostream &OS, const Module* = 0) const;
644 FoldingSet<SCEV> UniqueSCEVs;
645 BumpPtrAllocator SCEVAllocator;