1 //===- llvm/Analysis/ScalarEvolutionExpressions.h - SCEV Exprs --*- 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 // This file defines the classes used to represent and build scalar expressions.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H
15 #define LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H
17 #include "llvm/Analysis/ScalarEvolution.h"
18 #include "llvm/Support/ErrorHandling.h"
26 // These should be ordered in terms of increasing complexity to make the
28 scConstant, scTruncate, scZeroExtend, scSignExtend, scAddExpr, scMulExpr,
29 scUDivExpr, scAddRecExpr, scUMaxExpr, scSMaxExpr,
30 scFieldOffset, scAllocSize, scUnknown, scCouldNotCompute
33 //===--------------------------------------------------------------------===//
34 /// SCEVConstant - This class represents a constant integer value.
36 class SCEVConstant : public SCEV {
37 friend class ScalarEvolution;
40 SCEVConstant(const FoldingSetNodeID &ID, ConstantInt *v) :
41 SCEV(ID, scConstant), V(v) {}
43 ConstantInt *getValue() const { return V; }
45 virtual bool isLoopInvariant(const Loop *L) const {
49 virtual bool hasComputableLoopEvolution(const Loop *L) const {
50 return false; // Not loop variant
53 virtual const Type *getType() const;
55 virtual bool hasOperand(const SCEV *) const {
59 bool dominates(BasicBlock *BB, DominatorTree *DT) const {
63 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
67 virtual void print(raw_ostream &OS) const;
69 /// Methods for support type inquiry through isa, cast, and dyn_cast:
70 static inline bool classof(const SCEVConstant *S) { return true; }
71 static inline bool classof(const SCEV *S) {
72 return S->getSCEVType() == scConstant;
76 //===--------------------------------------------------------------------===//
77 /// SCEVCastExpr - This is the base class for unary cast operator classes.
79 class SCEVCastExpr : public SCEV {
84 SCEVCastExpr(const FoldingSetNodeID &ID,
85 unsigned SCEVTy, const SCEV *op, const Type *ty);
88 const SCEV *getOperand() const { return Op; }
89 virtual const Type *getType() const { return Ty; }
91 virtual bool isLoopInvariant(const Loop *L) const {
92 return Op->isLoopInvariant(L);
95 virtual bool hasComputableLoopEvolution(const Loop *L) const {
96 return Op->hasComputableLoopEvolution(L);
99 virtual bool hasOperand(const SCEV *O) const {
100 return Op == O || Op->hasOperand(O);
103 virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const;
105 virtual bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
107 /// Methods for support type inquiry through isa, cast, and dyn_cast:
108 static inline bool classof(const SCEVCastExpr *S) { return true; }
109 static inline bool classof(const SCEV *S) {
110 return S->getSCEVType() == scTruncate ||
111 S->getSCEVType() == scZeroExtend ||
112 S->getSCEVType() == scSignExtend;
116 //===--------------------------------------------------------------------===//
117 /// SCEVTruncateExpr - This class represents a truncation of an integer value
118 /// to a smaller integer value.
120 class SCEVTruncateExpr : public SCEVCastExpr {
121 friend class ScalarEvolution;
123 SCEVTruncateExpr(const FoldingSetNodeID &ID,
124 const SCEV *op, const Type *ty);
127 virtual void print(raw_ostream &OS) const;
129 /// Methods for support type inquiry through isa, cast, and dyn_cast:
130 static inline bool classof(const SCEVTruncateExpr *S) { return true; }
131 static inline bool classof(const SCEV *S) {
132 return S->getSCEVType() == scTruncate;
136 //===--------------------------------------------------------------------===//
137 /// SCEVZeroExtendExpr - This class represents a zero extension of a small
138 /// integer value to a larger integer value.
140 class SCEVZeroExtendExpr : public SCEVCastExpr {
141 friend class ScalarEvolution;
143 SCEVZeroExtendExpr(const FoldingSetNodeID &ID,
144 const SCEV *op, const Type *ty);
147 virtual void print(raw_ostream &OS) const;
149 /// Methods for support type inquiry through isa, cast, and dyn_cast:
150 static inline bool classof(const SCEVZeroExtendExpr *S) { return true; }
151 static inline bool classof(const SCEV *S) {
152 return S->getSCEVType() == scZeroExtend;
156 //===--------------------------------------------------------------------===//
157 /// SCEVSignExtendExpr - This class represents a sign extension of a small
158 /// integer value to a larger integer value.
160 class SCEVSignExtendExpr : public SCEVCastExpr {
161 friend class ScalarEvolution;
163 SCEVSignExtendExpr(const FoldingSetNodeID &ID,
164 const SCEV *op, const Type *ty);
167 virtual void print(raw_ostream &OS) const;
169 /// Methods for support type inquiry through isa, cast, and dyn_cast:
170 static inline bool classof(const SCEVSignExtendExpr *S) { return true; }
171 static inline bool classof(const SCEV *S) {
172 return S->getSCEVType() == scSignExtend;
177 //===--------------------------------------------------------------------===//
178 /// SCEVNAryExpr - This node is a base class providing common
179 /// functionality for n'ary operators.
181 class SCEVNAryExpr : public SCEV {
183 SmallVector<const SCEV *, 8> Operands;
185 SCEVNAryExpr(const FoldingSetNodeID &ID,
186 enum SCEVTypes T, const SmallVectorImpl<const SCEV *> &ops)
187 : SCEV(ID, T), Operands(ops.begin(), ops.end()) {}
190 unsigned getNumOperands() const { return (unsigned)Operands.size(); }
191 const SCEV *getOperand(unsigned i) const {
192 assert(i < Operands.size() && "Operand index out of range!");
196 const SmallVectorImpl<const SCEV *> &getOperands() const {
199 typedef SmallVectorImpl<const SCEV *>::const_iterator op_iterator;
200 op_iterator op_begin() const { return Operands.begin(); }
201 op_iterator op_end() const { return Operands.end(); }
203 virtual bool isLoopInvariant(const Loop *L) const {
204 for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
205 if (!getOperand(i)->isLoopInvariant(L)) return false;
209 // hasComputableLoopEvolution - N-ary expressions have computable loop
210 // evolutions iff they have at least one operand that varies with the loop,
211 // but that all varying operands are computable.
212 virtual bool hasComputableLoopEvolution(const Loop *L) const {
213 bool HasVarying = false;
214 for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
215 if (!getOperand(i)->isLoopInvariant(L)) {
216 if (getOperand(i)->hasComputableLoopEvolution(L))
224 virtual bool hasOperand(const SCEV *O) const {
225 for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
226 if (O == getOperand(i) || getOperand(i)->hasOperand(O))
231 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
233 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
235 virtual const Type *getType() const { return getOperand(0)->getType(); }
237 bool hasNoUnsignedWrap() const { return SubclassData & (1 << 0); }
238 void setHasNoUnsignedWrap(bool B) {
239 SubclassData = (SubclassData & ~(1 << 0)) | (B << 0);
241 bool hasNoSignedWrap() const { return SubclassData & (1 << 1); }
242 void setHasNoSignedWrap(bool B) {
243 SubclassData = (SubclassData & ~(1 << 1)) | (B << 1);
246 /// Methods for support type inquiry through isa, cast, and dyn_cast:
247 static inline bool classof(const SCEVNAryExpr *S) { return true; }
248 static inline bool classof(const SCEV *S) {
249 return S->getSCEVType() == scAddExpr ||
250 S->getSCEVType() == scMulExpr ||
251 S->getSCEVType() == scSMaxExpr ||
252 S->getSCEVType() == scUMaxExpr ||
253 S->getSCEVType() == scAddRecExpr;
257 //===--------------------------------------------------------------------===//
258 /// SCEVCommutativeExpr - This node is the base class for n'ary commutative
261 class SCEVCommutativeExpr : public SCEVNAryExpr {
263 SCEVCommutativeExpr(const FoldingSetNodeID &ID,
265 const SmallVectorImpl<const SCEV *> &ops)
266 : SCEVNAryExpr(ID, T, ops) {}
269 virtual const char *getOperationStr() const = 0;
271 virtual void print(raw_ostream &OS) const;
273 /// Methods for support type inquiry through isa, cast, and dyn_cast:
274 static inline bool classof(const SCEVCommutativeExpr *S) { return true; }
275 static inline bool classof(const SCEV *S) {
276 return S->getSCEVType() == scAddExpr ||
277 S->getSCEVType() == scMulExpr ||
278 S->getSCEVType() == scSMaxExpr ||
279 S->getSCEVType() == scUMaxExpr;
284 //===--------------------------------------------------------------------===//
285 /// SCEVAddExpr - This node represents an addition of some number of SCEVs.
287 class SCEVAddExpr : public SCEVCommutativeExpr {
288 friend class ScalarEvolution;
290 SCEVAddExpr(const FoldingSetNodeID &ID,
291 const SmallVectorImpl<const SCEV *> &ops)
292 : SCEVCommutativeExpr(ID, scAddExpr, ops) {
296 virtual const char *getOperationStr() const { return " + "; }
298 virtual const Type *getType() const {
299 // Use the type of the last operand, which is likely to be a pointer
300 // type, if there is one. This doesn't usually matter, but it can help
301 // reduce casts when the expressions are expanded.
302 return getOperand(getNumOperands() - 1)->getType();
305 /// Methods for support type inquiry through isa, cast, and dyn_cast:
306 static inline bool classof(const SCEVAddExpr *S) { return true; }
307 static inline bool classof(const SCEV *S) {
308 return S->getSCEVType() == scAddExpr;
312 //===--------------------------------------------------------------------===//
313 /// SCEVMulExpr - This node represents multiplication of some number of SCEVs.
315 class SCEVMulExpr : public SCEVCommutativeExpr {
316 friend class ScalarEvolution;
318 SCEVMulExpr(const FoldingSetNodeID &ID,
319 const SmallVectorImpl<const SCEV *> &ops)
320 : SCEVCommutativeExpr(ID, scMulExpr, ops) {
324 virtual const char *getOperationStr() const { return " * "; }
326 /// Methods for support type inquiry through isa, cast, and dyn_cast:
327 static inline bool classof(const SCEVMulExpr *S) { return true; }
328 static inline bool classof(const SCEV *S) {
329 return S->getSCEVType() == scMulExpr;
334 //===--------------------------------------------------------------------===//
335 /// SCEVUDivExpr - This class represents a binary unsigned division operation.
337 class SCEVUDivExpr : public SCEV {
338 friend class ScalarEvolution;
342 SCEVUDivExpr(const FoldingSetNodeID &ID, const SCEV *lhs, const SCEV *rhs)
343 : SCEV(ID, scUDivExpr), LHS(lhs), RHS(rhs) {}
346 const SCEV *getLHS() const { return LHS; }
347 const SCEV *getRHS() const { return RHS; }
349 virtual bool isLoopInvariant(const Loop *L) const {
350 return LHS->isLoopInvariant(L) && RHS->isLoopInvariant(L);
353 virtual bool hasComputableLoopEvolution(const Loop *L) const {
354 return LHS->hasComputableLoopEvolution(L) &&
355 RHS->hasComputableLoopEvolution(L);
358 virtual bool hasOperand(const SCEV *O) const {
359 return O == LHS || O == RHS || LHS->hasOperand(O) || RHS->hasOperand(O);
362 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
364 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
366 virtual const Type *getType() const;
368 void print(raw_ostream &OS) const;
370 /// Methods for support type inquiry through isa, cast, and dyn_cast:
371 static inline bool classof(const SCEVUDivExpr *S) { return true; }
372 static inline bool classof(const SCEV *S) {
373 return S->getSCEVType() == scUDivExpr;
378 //===--------------------------------------------------------------------===//
379 /// SCEVAddRecExpr - This node represents a polynomial recurrence on the trip
380 /// count of the specified loop. This is the primary focus of the
381 /// ScalarEvolution framework; all the other SCEV subclasses are mostly just
382 /// supporting infrastructure to allow SCEVAddRecExpr expressions to be
383 /// created and analyzed.
385 /// All operands of an AddRec are required to be loop invariant.
387 class SCEVAddRecExpr : public SCEVNAryExpr {
388 friend class ScalarEvolution;
392 SCEVAddRecExpr(const FoldingSetNodeID &ID,
393 const SmallVectorImpl<const SCEV *> &ops, const Loop *l)
394 : SCEVNAryExpr(ID, scAddRecExpr, ops), L(l) {
395 for (size_t i = 0, e = Operands.size(); i != e; ++i)
396 assert(Operands[i]->isLoopInvariant(l) &&
397 "Operands of AddRec must be loop-invariant!");
401 const SCEV *getStart() const { return Operands[0]; }
402 const Loop *getLoop() const { return L; }
404 /// getStepRecurrence - This method constructs and returns the recurrence
405 /// indicating how much this expression steps by. If this is a polynomial
406 /// of degree N, it returns a chrec of degree N-1.
407 const SCEV *getStepRecurrence(ScalarEvolution &SE) const {
408 if (isAffine()) return getOperand(1);
409 return SE.getAddRecExpr(SmallVector<const SCEV *, 3>(op_begin()+1,
414 virtual bool hasComputableLoopEvolution(const Loop *QL) const {
415 if (L == QL) return true;
419 virtual bool isLoopInvariant(const Loop *QueryLoop) const;
421 /// isAffine - Return true if this is an affine AddRec (i.e., it represents
422 /// an expressions A+B*x where A and B are loop invariant values.
423 bool isAffine() const {
424 // We know that the start value is invariant. This expression is thus
425 // affine iff the step is also invariant.
426 return getNumOperands() == 2;
429 /// isQuadratic - Return true if this is an quadratic AddRec (i.e., it
430 /// represents an expressions A+B*x+C*x^2 where A, B and C are loop
431 /// invariant values. This corresponds to an addrec of the form {L,+,M,+,N}
432 bool isQuadratic() const {
433 return getNumOperands() == 3;
436 /// evaluateAtIteration - Return the value of this chain of recurrences at
437 /// the specified iteration number.
438 const SCEV *evaluateAtIteration(const SCEV *It, ScalarEvolution &SE) const;
440 /// getNumIterationsInRange - Return the number of iterations of this loop
441 /// that produce values in the specified constant range. Another way of
442 /// looking at this is that it returns the first iteration number where the
443 /// value is not in the condition, thus computing the exit count. If the
444 /// iteration count can't be computed, an instance of SCEVCouldNotCompute is
446 const SCEV *getNumIterationsInRange(ConstantRange Range,
447 ScalarEvolution &SE) const;
449 /// getPostIncExpr - Return an expression representing the value of
450 /// this expression one iteration of the loop ahead.
451 const SCEVAddRecExpr *getPostIncExpr(ScalarEvolution &SE) const {
452 return cast<SCEVAddRecExpr>(SE.getAddExpr(this, getStepRecurrence(SE)));
455 virtual void print(raw_ostream &OS) const;
457 /// Methods for support type inquiry through isa, cast, and dyn_cast:
458 static inline bool classof(const SCEVAddRecExpr *S) { return true; }
459 static inline bool classof(const SCEV *S) {
460 return S->getSCEVType() == scAddRecExpr;
465 //===--------------------------------------------------------------------===//
466 /// SCEVSMaxExpr - This class represents a signed maximum selection.
468 class SCEVSMaxExpr : public SCEVCommutativeExpr {
469 friend class ScalarEvolution;
471 SCEVSMaxExpr(const FoldingSetNodeID &ID,
472 const SmallVectorImpl<const SCEV *> &ops)
473 : SCEVCommutativeExpr(ID, scSMaxExpr, ops) {
474 // Max never overflows.
475 setHasNoUnsignedWrap(true);
476 setHasNoSignedWrap(true);
480 virtual const char *getOperationStr() const { return " smax "; }
482 /// Methods for support type inquiry through isa, cast, and dyn_cast:
483 static inline bool classof(const SCEVSMaxExpr *S) { return true; }
484 static inline bool classof(const SCEV *S) {
485 return S->getSCEVType() == scSMaxExpr;
490 //===--------------------------------------------------------------------===//
491 /// SCEVUMaxExpr - This class represents an unsigned maximum selection.
493 class SCEVUMaxExpr : public SCEVCommutativeExpr {
494 friend class ScalarEvolution;
496 SCEVUMaxExpr(const FoldingSetNodeID &ID,
497 const SmallVectorImpl<const SCEV *> &ops)
498 : SCEVCommutativeExpr(ID, scUMaxExpr, ops) {
499 // Max never overflows.
500 setHasNoUnsignedWrap(true);
501 setHasNoSignedWrap(true);
505 virtual const char *getOperationStr() const { return " umax "; }
507 /// Methods for support type inquiry through isa, cast, and dyn_cast:
508 static inline bool classof(const SCEVUMaxExpr *S) { return true; }
509 static inline bool classof(const SCEV *S) {
510 return S->getSCEVType() == scUMaxExpr;
514 //===--------------------------------------------------------------------===//
515 /// SCEVTargetDataConstant - This node is the base class for representing
516 /// target-dependent values in a target-independent way.
518 class SCEVTargetDataConstant : public SCEV {
521 SCEVTargetDataConstant(const FoldingSetNodeID &ID, enum SCEVTypes T,
523 SCEV(ID, T), Ty(ty) {}
526 virtual bool isLoopInvariant(const Loop *) const { return true; }
527 virtual bool hasComputableLoopEvolution(const Loop *) const {
528 return false; // not computable
531 virtual bool hasOperand(const SCEV *) const {
535 bool dominates(BasicBlock *, DominatorTree *) const {
539 bool properlyDominates(BasicBlock *, DominatorTree *) const {
543 virtual const Type *getType() const { return Ty; }
545 /// Methods for support type inquiry through isa, cast, and dyn_cast:
546 static inline bool classof(const SCEVTargetDataConstant *S) { return true; }
547 static inline bool classof(const SCEV *S) {
548 return S->getSCEVType() == scFieldOffset ||
549 S->getSCEVType() == scAllocSize;
553 //===--------------------------------------------------------------------===//
554 /// SCEVFieldOffsetExpr - This node represents an offsetof expression.
556 class SCEVFieldOffsetExpr : public SCEVTargetDataConstant {
557 friend class ScalarEvolution;
559 const StructType *STy;
561 SCEVFieldOffsetExpr(const FoldingSetNodeID &ID, const Type *ty,
562 const StructType *sty, unsigned fieldno) :
563 SCEVTargetDataConstant(ID, scFieldOffset, ty),
564 STy(sty), FieldNo(fieldno) {}
567 const StructType *getStructType() const { return STy; }
568 unsigned getFieldNo() const { return FieldNo; }
570 virtual void print(raw_ostream &OS) const;
572 /// Methods for support type inquiry through isa, cast, and dyn_cast:
573 static inline bool classof(const SCEVFieldOffsetExpr *S) { return true; }
574 static inline bool classof(const SCEV *S) {
575 return S->getSCEVType() == scFieldOffset;
579 //===--------------------------------------------------------------------===//
580 /// SCEVAllocSize - This node represents a sizeof expression.
582 class SCEVAllocSizeExpr : public SCEVTargetDataConstant {
583 friend class ScalarEvolution;
586 SCEVAllocSizeExpr(const FoldingSetNodeID &ID,
587 const Type *ty, const Type *allocty) :
588 SCEVTargetDataConstant(ID, scAllocSize, ty),
592 const Type *getAllocType() const { return AllocTy; }
594 virtual void print(raw_ostream &OS) const;
596 /// Methods for support type inquiry through isa, cast, and dyn_cast:
597 static inline bool classof(const SCEVAllocSizeExpr *S) { return true; }
598 static inline bool classof(const SCEV *S) {
599 return S->getSCEVType() == scAllocSize;
603 //===--------------------------------------------------------------------===//
604 /// SCEVUnknown - This means that we are dealing with an entirely unknown SCEV
605 /// value, and only represent it as its LLVM Value. This is the "bottom"
606 /// value for the analysis.
608 class SCEVUnknown : public SCEV {
609 friend class ScalarEvolution;
612 SCEVUnknown(const FoldingSetNodeID &ID, Value *v) :
613 SCEV(ID, scUnknown), V(v) {}
616 Value *getValue() const { return V; }
618 virtual bool isLoopInvariant(const Loop *L) const;
619 virtual bool hasComputableLoopEvolution(const Loop *QL) const {
620 return false; // not computable
623 virtual bool hasOperand(const SCEV *) const {
627 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
629 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
631 virtual const Type *getType() const;
633 virtual void print(raw_ostream &OS) const;
635 /// Methods for support type inquiry through isa, cast, and dyn_cast:
636 static inline bool classof(const SCEVUnknown *S) { return true; }
637 static inline bool classof(const SCEV *S) {
638 return S->getSCEVType() == scUnknown;
642 /// SCEVVisitor - This class defines a simple visitor class that may be used
643 /// for various SCEV analysis purposes.
644 template<typename SC, typename RetVal=void>
646 RetVal visit(const SCEV *S) {
647 switch (S->getSCEVType()) {
649 return ((SC*)this)->visitConstant((const SCEVConstant*)S);
651 return ((SC*)this)->visitTruncateExpr((const SCEVTruncateExpr*)S);
653 return ((SC*)this)->visitZeroExtendExpr((const SCEVZeroExtendExpr*)S);
655 return ((SC*)this)->visitSignExtendExpr((const SCEVSignExtendExpr*)S);
657 return ((SC*)this)->visitAddExpr((const SCEVAddExpr*)S);
659 return ((SC*)this)->visitMulExpr((const SCEVMulExpr*)S);
661 return ((SC*)this)->visitUDivExpr((const SCEVUDivExpr*)S);
663 return ((SC*)this)->visitAddRecExpr((const SCEVAddRecExpr*)S);
665 return ((SC*)this)->visitSMaxExpr((const SCEVSMaxExpr*)S);
667 return ((SC*)this)->visitUMaxExpr((const SCEVUMaxExpr*)S);
669 return ((SC*)this)->visitFieldOffsetExpr((const SCEVFieldOffsetExpr*)S);
671 return ((SC*)this)->visitAllocSizeExpr((const SCEVAllocSizeExpr*)S);
673 return ((SC*)this)->visitUnknown((const SCEVUnknown*)S);
674 case scCouldNotCompute:
675 return ((SC*)this)->visitCouldNotCompute((const SCEVCouldNotCompute*)S);
677 llvm_unreachable("Unknown SCEV type!");
681 RetVal visitCouldNotCompute(const SCEVCouldNotCompute *S) {
682 llvm_unreachable("Invalid use of SCEVCouldNotCompute!");