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, scUnknown,
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 const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
57 ScalarEvolution &SE) const {
61 bool dominates(BasicBlock *BB, DominatorTree *DT) const {
65 virtual void print(raw_ostream &OS) const;
67 /// Methods for support type inquiry through isa, cast, and dyn_cast:
68 static inline bool classof(const SCEVConstant *S) { return true; }
69 static inline bool classof(const SCEV *S) {
70 return S->getSCEVType() == scConstant;
74 //===--------------------------------------------------------------------===//
75 /// SCEVCastExpr - This is the base class for unary cast operator classes.
77 class SCEVCastExpr : public SCEV {
82 SCEVCastExpr(const FoldingSetNodeID &ID,
83 unsigned SCEVTy, const SCEV *op, const Type *ty);
86 const SCEV *getOperand() const { return Op; }
87 virtual const Type *getType() const { return Ty; }
89 virtual bool isLoopInvariant(const Loop *L) const {
90 return Op->isLoopInvariant(L);
93 virtual bool hasComputableLoopEvolution(const Loop *L) const {
94 return Op->hasComputableLoopEvolution(L);
97 virtual bool dominates(BasicBlock *BB, DominatorTree *DT) const;
99 /// Methods for support type inquiry through isa, cast, and dyn_cast:
100 static inline bool classof(const SCEVCastExpr *S) { return true; }
101 static inline bool classof(const SCEV *S) {
102 return S->getSCEVType() == scTruncate ||
103 S->getSCEVType() == scZeroExtend ||
104 S->getSCEVType() == scSignExtend;
108 //===--------------------------------------------------------------------===//
109 /// SCEVTruncateExpr - This class represents a truncation of an integer value
110 /// to a smaller integer value.
112 class SCEVTruncateExpr : public SCEVCastExpr {
113 friend class ScalarEvolution;
115 SCEVTruncateExpr(const FoldingSetNodeID &ID,
116 const SCEV *op, const Type *ty);
119 const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
121 ScalarEvolution &SE) const {
122 const SCEV *H = Op->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
125 return SE.getTruncateExpr(H, Ty);
128 virtual void print(raw_ostream &OS) const;
130 /// Methods for support type inquiry through isa, cast, and dyn_cast:
131 static inline bool classof(const SCEVTruncateExpr *S) { return true; }
132 static inline bool classof(const SCEV *S) {
133 return S->getSCEVType() == scTruncate;
137 //===--------------------------------------------------------------------===//
138 /// SCEVZeroExtendExpr - This class represents a zero extension of a small
139 /// integer value to a larger integer value.
141 class SCEVZeroExtendExpr : public SCEVCastExpr {
142 friend class ScalarEvolution;
144 SCEVZeroExtendExpr(const FoldingSetNodeID &ID,
145 const SCEV *op, const Type *ty);
148 const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
150 ScalarEvolution &SE) const {
151 const SCEV *H = Op->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
154 return SE.getZeroExtendExpr(H, Ty);
157 virtual void print(raw_ostream &OS) const;
159 /// Methods for support type inquiry through isa, cast, and dyn_cast:
160 static inline bool classof(const SCEVZeroExtendExpr *S) { return true; }
161 static inline bool classof(const SCEV *S) {
162 return S->getSCEVType() == scZeroExtend;
166 //===--------------------------------------------------------------------===//
167 /// SCEVSignExtendExpr - This class represents a sign extension of a small
168 /// integer value to a larger integer value.
170 class SCEVSignExtendExpr : public SCEVCastExpr {
171 friend class ScalarEvolution;
173 SCEVSignExtendExpr(const FoldingSetNodeID &ID,
174 const SCEV *op, const Type *ty);
177 const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
179 ScalarEvolution &SE) const {
180 const SCEV *H = Op->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
183 return SE.getSignExtendExpr(H, Ty);
186 virtual void print(raw_ostream &OS) const;
188 /// Methods for support type inquiry through isa, cast, and dyn_cast:
189 static inline bool classof(const SCEVSignExtendExpr *S) { return true; }
190 static inline bool classof(const SCEV *S) {
191 return S->getSCEVType() == scSignExtend;
196 //===--------------------------------------------------------------------===//
197 /// SCEVNAryExpr - This node is a base class providing common
198 /// functionality for n'ary operators.
200 class SCEVNAryExpr : public SCEV {
202 SmallVector<const SCEV *, 8> Operands;
204 SCEVNAryExpr(const FoldingSetNodeID &ID,
205 enum SCEVTypes T, const SmallVectorImpl<const SCEV *> &ops)
206 : SCEV(ID, T), Operands(ops.begin(), ops.end()) {}
209 unsigned getNumOperands() const { return (unsigned)Operands.size(); }
210 const SCEV *getOperand(unsigned i) const {
211 assert(i < Operands.size() && "Operand index out of range!");
215 const SmallVectorImpl<const SCEV *> &getOperands() const {
218 typedef SmallVectorImpl<const SCEV *>::const_iterator op_iterator;
219 op_iterator op_begin() const { return Operands.begin(); }
220 op_iterator op_end() const { return Operands.end(); }
222 virtual bool isLoopInvariant(const Loop *L) const {
223 for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
224 if (!getOperand(i)->isLoopInvariant(L)) return false;
228 // hasComputableLoopEvolution - N-ary expressions have computable loop
229 // evolutions iff they have at least one operand that varies with the loop,
230 // but that all varying operands are computable.
231 virtual bool hasComputableLoopEvolution(const Loop *L) const {
232 bool HasVarying = false;
233 for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
234 if (!getOperand(i)->isLoopInvariant(L)) {
235 if (getOperand(i)->hasComputableLoopEvolution(L))
243 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
245 virtual const Type *getType() const { return getOperand(0)->getType(); }
247 /// Methods for support type inquiry through isa, cast, and dyn_cast:
248 static inline bool classof(const SCEVNAryExpr *S) { return true; }
249 static inline bool classof(const SCEV *S) {
250 return S->getSCEVType() == scAddExpr ||
251 S->getSCEVType() == scMulExpr ||
252 S->getSCEVType() == scSMaxExpr ||
253 S->getSCEVType() == scUMaxExpr ||
254 S->getSCEVType() == scAddRecExpr;
258 //===--------------------------------------------------------------------===//
259 /// SCEVCommutativeExpr - This node is the base class for n'ary commutative
262 class SCEVCommutativeExpr : public SCEVNAryExpr {
264 SCEVCommutativeExpr(const FoldingSetNodeID &ID,
266 const SmallVectorImpl<const SCEV *> &ops)
267 : SCEVNAryExpr(ID, T, ops) {}
270 const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
272 ScalarEvolution &SE) const;
274 virtual const char *getOperationStr() const = 0;
276 virtual void print(raw_ostream &OS) const;
278 /// Methods for support type inquiry through isa, cast, and dyn_cast:
279 static inline bool classof(const SCEVCommutativeExpr *S) { return true; }
280 static inline bool classof(const SCEV *S) {
281 return S->getSCEVType() == scAddExpr ||
282 S->getSCEVType() == scMulExpr ||
283 S->getSCEVType() == scSMaxExpr ||
284 S->getSCEVType() == scUMaxExpr;
289 //===--------------------------------------------------------------------===//
290 /// SCEVAddExpr - This node represents an addition of some number of SCEVs.
292 class SCEVAddExpr : public SCEVCommutativeExpr {
293 friend class ScalarEvolution;
295 SCEVAddExpr(const FoldingSetNodeID &ID,
296 const SmallVectorImpl<const SCEV *> &ops)
297 : SCEVCommutativeExpr(ID, scAddExpr, ops) {
301 virtual const char *getOperationStr() const { return " + "; }
303 /// Methods for support type inquiry through isa, cast, and dyn_cast:
304 static inline bool classof(const SCEVAddExpr *S) { return true; }
305 static inline bool classof(const SCEV *S) {
306 return S->getSCEVType() == scAddExpr;
310 //===--------------------------------------------------------------------===//
311 /// SCEVMulExpr - This node represents multiplication of some number of SCEVs.
313 class SCEVMulExpr : public SCEVCommutativeExpr {
314 friend class ScalarEvolution;
316 SCEVMulExpr(const FoldingSetNodeID &ID,
317 const SmallVectorImpl<const SCEV *> &ops)
318 : SCEVCommutativeExpr(ID, scMulExpr, ops) {
322 virtual const char *getOperationStr() const { return " * "; }
324 /// Methods for support type inquiry through isa, cast, and dyn_cast:
325 static inline bool classof(const SCEVMulExpr *S) { return true; }
326 static inline bool classof(const SCEV *S) {
327 return S->getSCEVType() == scMulExpr;
332 //===--------------------------------------------------------------------===//
333 /// SCEVUDivExpr - This class represents a binary unsigned division operation.
335 class SCEVUDivExpr : public SCEV {
336 friend class ScalarEvolution;
340 SCEVUDivExpr(const FoldingSetNodeID &ID, const SCEV *lhs, const SCEV *rhs)
341 : SCEV(ID, scUDivExpr), LHS(lhs), RHS(rhs) {}
344 const SCEV *getLHS() const { return LHS; }
345 const SCEV *getRHS() const { return RHS; }
347 virtual bool isLoopInvariant(const Loop *L) const {
348 return LHS->isLoopInvariant(L) && RHS->isLoopInvariant(L);
351 virtual bool hasComputableLoopEvolution(const Loop *L) const {
352 return LHS->hasComputableLoopEvolution(L) &&
353 RHS->hasComputableLoopEvolution(L);
356 const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
358 ScalarEvolution &SE) const {
359 const SCEV *L = LHS->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
360 const SCEV *R = RHS->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
361 if (L == LHS && R == RHS)
364 return SE.getUDivExpr(L, R);
367 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
369 virtual const Type *getType() const;
371 void print(raw_ostream &OS) const;
373 /// Methods for support type inquiry through isa, cast, and dyn_cast:
374 static inline bool classof(const SCEVUDivExpr *S) { return true; }
375 static inline bool classof(const SCEV *S) {
376 return S->getSCEVType() == scUDivExpr;
381 //===--------------------------------------------------------------------===//
382 /// SCEVAddRecExpr - This node represents a polynomial recurrence on the trip
383 /// count of the specified loop. This is the primary focus of the
384 /// ScalarEvolution framework; all the other SCEV subclasses are mostly just
385 /// supporting infrastructure to allow SCEVAddRecExpr expressions to be
386 /// created and analyzed.
388 /// All operands of an AddRec are required to be loop invariant.
390 class SCEVAddRecExpr : public SCEVNAryExpr {
391 friend class ScalarEvolution;
395 SCEVAddRecExpr(const FoldingSetNodeID &ID,
396 const SmallVectorImpl<const SCEV *> &ops, const Loop *l)
397 : SCEVNAryExpr(ID, scAddRecExpr, ops), L(l) {
398 for (size_t i = 0, e = Operands.size(); i != e; ++i)
399 assert(Operands[i]->isLoopInvariant(l) &&
400 "Operands of AddRec must be loop-invariant!");
404 const SCEV *getStart() const { return Operands[0]; }
405 const Loop *getLoop() const { return L; }
407 /// getStepRecurrence - This method constructs and returns the recurrence
408 /// indicating how much this expression steps by. If this is a polynomial
409 /// of degree N, it returns a chrec of degree N-1.
410 const SCEV *getStepRecurrence(ScalarEvolution &SE) const {
411 if (isAffine()) return getOperand(1);
412 return SE.getAddRecExpr(SmallVector<const SCEV *, 3>(op_begin()+1,
417 virtual bool hasComputableLoopEvolution(const Loop *QL) const {
418 if (L == QL) return true;
422 virtual bool isLoopInvariant(const Loop *QueryLoop) const;
424 /// isAffine - Return true if this is an affine AddRec (i.e., it represents
425 /// an expressions A+B*x where A and B are loop invariant values.
426 bool isAffine() const {
427 // We know that the start value is invariant. This expression is thus
428 // affine iff the step is also invariant.
429 return getNumOperands() == 2;
432 /// isQuadratic - Return true if this is an quadratic AddRec (i.e., it
433 /// represents an expressions A+B*x+C*x^2 where A, B and C are loop
434 /// invariant values. This corresponds to an addrec of the form {L,+,M,+,N}
435 bool isQuadratic() const {
436 return getNumOperands() == 3;
439 /// evaluateAtIteration - Return the value of this chain of recurrences at
440 /// the specified iteration number.
441 const SCEV *evaluateAtIteration(const SCEV *It, ScalarEvolution &SE) const;
443 /// getNumIterationsInRange - Return the number of iterations of this loop
444 /// that produce values in the specified constant range. Another way of
445 /// looking at this is that it returns the first iteration number where the
446 /// value is not in the condition, thus computing the exit count. If the
447 /// iteration count can't be computed, an instance of SCEVCouldNotCompute is
449 const SCEV *getNumIterationsInRange(ConstantRange Range,
450 ScalarEvolution &SE) const;
452 const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
454 ScalarEvolution &SE) const;
456 /// getPostIncExpr - Return an expression representing the value of
457 /// this expression one iteration of the loop ahead.
458 const SCEV *getPostIncExpr(ScalarEvolution &SE) const {
459 return SE.getAddExpr(this, getStepRecurrence(SE));
462 virtual void print(raw_ostream &OS) const;
464 /// Methods for support type inquiry through isa, cast, and dyn_cast:
465 static inline bool classof(const SCEVAddRecExpr *S) { return true; }
466 static inline bool classof(const SCEV *S) {
467 return S->getSCEVType() == scAddRecExpr;
472 //===--------------------------------------------------------------------===//
473 /// SCEVSMaxExpr - This class represents a signed maximum selection.
475 class SCEVSMaxExpr : public SCEVCommutativeExpr {
476 friend class ScalarEvolution;
478 SCEVSMaxExpr(const FoldingSetNodeID &ID,
479 const SmallVectorImpl<const SCEV *> &ops)
480 : SCEVCommutativeExpr(ID, scSMaxExpr, ops) {
484 virtual const char *getOperationStr() const { return " smax "; }
486 /// Methods for support type inquiry through isa, cast, and dyn_cast:
487 static inline bool classof(const SCEVSMaxExpr *S) { return true; }
488 static inline bool classof(const SCEV *S) {
489 return S->getSCEVType() == scSMaxExpr;
494 //===--------------------------------------------------------------------===//
495 /// SCEVUMaxExpr - This class represents an unsigned maximum selection.
497 class SCEVUMaxExpr : public SCEVCommutativeExpr {
498 friend class ScalarEvolution;
500 SCEVUMaxExpr(const FoldingSetNodeID &ID,
501 const SmallVectorImpl<const SCEV *> &ops)
502 : SCEVCommutativeExpr(ID, scUMaxExpr, ops) {
506 virtual const char *getOperationStr() const { return " umax "; }
508 /// Methods for support type inquiry through isa, cast, and dyn_cast:
509 static inline bool classof(const SCEVUMaxExpr *S) { return true; }
510 static inline bool classof(const SCEV *S) {
511 return S->getSCEVType() == scUMaxExpr;
516 //===--------------------------------------------------------------------===//
517 /// SCEVUnknown - This means that we are dealing with an entirely unknown SCEV
518 /// value, and only represent it as it's LLVM Value. This is the "bottom"
519 /// value for the analysis.
521 class SCEVUnknown : public SCEV {
522 friend class ScalarEvolution;
525 SCEVUnknown(const FoldingSetNodeID &ID, Value *v) :
526 SCEV(ID, scUnknown), V(v) {}
529 Value *getValue() const { return V; }
531 virtual bool isLoopInvariant(const Loop *L) const;
532 virtual bool hasComputableLoopEvolution(const Loop *QL) const {
533 return false; // not computable
536 const SCEV *replaceSymbolicValuesWithConcrete(const SCEV *Sym,
538 ScalarEvolution &SE) const {
539 if (&*Sym == this) return Conc;
543 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
545 virtual const Type *getType() const;
547 virtual void print(raw_ostream &OS) const;
549 /// Methods for support type inquiry through isa, cast, and dyn_cast:
550 static inline bool classof(const SCEVUnknown *S) { return true; }
551 static inline bool classof(const SCEV *S) {
552 return S->getSCEVType() == scUnknown;
556 /// SCEVVisitor - This class defines a simple visitor class that may be used
557 /// for various SCEV analysis purposes.
558 template<typename SC, typename RetVal=void>
560 RetVal visit(const SCEV *S) {
561 switch (S->getSCEVType()) {
563 return ((SC*)this)->visitConstant((const SCEVConstant*)S);
565 return ((SC*)this)->visitTruncateExpr((const SCEVTruncateExpr*)S);
567 return ((SC*)this)->visitZeroExtendExpr((const SCEVZeroExtendExpr*)S);
569 return ((SC*)this)->visitSignExtendExpr((const SCEVSignExtendExpr*)S);
571 return ((SC*)this)->visitAddExpr((const SCEVAddExpr*)S);
573 return ((SC*)this)->visitMulExpr((const SCEVMulExpr*)S);
575 return ((SC*)this)->visitUDivExpr((const SCEVUDivExpr*)S);
577 return ((SC*)this)->visitAddRecExpr((const SCEVAddRecExpr*)S);
579 return ((SC*)this)->visitSMaxExpr((const SCEVSMaxExpr*)S);
581 return ((SC*)this)->visitUMaxExpr((const SCEVUMaxExpr*)S);
583 return ((SC*)this)->visitUnknown((const SCEVUnknown*)S);
584 case scCouldNotCompute:
585 return ((SC*)this)->visitCouldNotCompute((const SCEVCouldNotCompute*)S);
587 llvm_unreachable("Unknown SCEV type!");
591 RetVal visitCouldNotCompute(const SCEVCouldNotCompute *S) {
592 llvm_unreachable("Invalid use of SCEVCouldNotCompute!");