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 scUnknown, scCouldNotCompute
33 //===--------------------------------------------------------------------===//
34 /// SCEVConstant - This class represents a constant integer value.
36 class SCEVConstant : public SCEV {
37 friend class ScalarEvolution;
40 SCEVConstant(const FoldingSetNodeIDRef 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 FoldingSetNodeIDRef 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 FoldingSetNodeIDRef ID,
124 const SCEV *op, const Type *ty);
127 virtual void print(raw_ostream &OS) const;
129 virtual bool hasComputableLoopEvolution(const Loop *QL) const {
130 // Not computable. A truncate of an addrec is always folded into
135 /// Methods for support type inquiry through isa, cast, and dyn_cast:
136 static inline bool classof(const SCEVTruncateExpr *S) { return true; }
137 static inline bool classof(const SCEV *S) {
138 return S->getSCEVType() == scTruncate;
142 //===--------------------------------------------------------------------===//
143 /// SCEVZeroExtendExpr - This class represents a zero extension of a small
144 /// integer value to a larger integer value.
146 class SCEVZeroExtendExpr : public SCEVCastExpr {
147 friend class ScalarEvolution;
149 SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID,
150 const SCEV *op, const Type *ty);
153 virtual void print(raw_ostream &OS) const;
155 /// Methods for support type inquiry through isa, cast, and dyn_cast:
156 static inline bool classof(const SCEVZeroExtendExpr *S) { return true; }
157 static inline bool classof(const SCEV *S) {
158 return S->getSCEVType() == scZeroExtend;
162 //===--------------------------------------------------------------------===//
163 /// SCEVSignExtendExpr - This class represents a sign extension of a small
164 /// integer value to a larger integer value.
166 class SCEVSignExtendExpr : public SCEVCastExpr {
167 friend class ScalarEvolution;
169 SCEVSignExtendExpr(const FoldingSetNodeIDRef ID,
170 const SCEV *op, const Type *ty);
173 virtual void print(raw_ostream &OS) const;
175 /// Methods for support type inquiry through isa, cast, and dyn_cast:
176 static inline bool classof(const SCEVSignExtendExpr *S) { return true; }
177 static inline bool classof(const SCEV *S) {
178 return S->getSCEVType() == scSignExtend;
183 //===--------------------------------------------------------------------===//
184 /// SCEVNAryExpr - This node is a base class providing common
185 /// functionality for n'ary operators.
187 class SCEVNAryExpr : public SCEV {
189 // Since SCEVs are immutable, ScalarEvolution allocates operand
190 // arrays with its SCEVAllocator, so this class just needs a simple
191 // pointer rather than a more elaborate vector-like data structure.
192 // This also avoids the need for a non-trivial destructor.
193 const SCEV *const *Operands;
196 SCEVNAryExpr(const FoldingSetNodeIDRef ID,
197 enum SCEVTypes T, const SCEV *const *O, size_t N)
198 : SCEV(ID, T), Operands(O), NumOperands(N) {}
201 size_t getNumOperands() const { return NumOperands; }
202 const SCEV *getOperand(unsigned i) const {
203 assert(i < NumOperands && "Operand index out of range!");
207 typedef const SCEV *const *op_iterator;
208 op_iterator op_begin() const { return Operands; }
209 op_iterator op_end() const { return Operands + NumOperands; }
211 virtual bool isLoopInvariant(const Loop *L) const;
213 // hasComputableLoopEvolution - N-ary expressions have computable loop
214 // evolutions iff they have at least one operand that varies with the loop,
215 // but that all varying operands are computable.
216 virtual bool hasComputableLoopEvolution(const Loop *L) const;
218 virtual bool hasOperand(const SCEV *O) const;
220 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
222 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
224 virtual const Type *getType() const { return getOperand(0)->getType(); }
226 bool hasNoUnsignedWrap() const { return SubclassData & (1 << 0); }
227 void setHasNoUnsignedWrap(bool B) {
228 SubclassData = (SubclassData & ~(1 << 0)) | (B << 0);
230 bool hasNoSignedWrap() const { return SubclassData & (1 << 1); }
231 void setHasNoSignedWrap(bool B) {
232 SubclassData = (SubclassData & ~(1 << 1)) | (B << 1);
235 /// Methods for support type inquiry through isa, cast, and dyn_cast:
236 static inline bool classof(const SCEVNAryExpr *S) { return true; }
237 static inline bool classof(const SCEV *S) {
238 return S->getSCEVType() == scAddExpr ||
239 S->getSCEVType() == scMulExpr ||
240 S->getSCEVType() == scSMaxExpr ||
241 S->getSCEVType() == scUMaxExpr ||
242 S->getSCEVType() == scAddRecExpr;
246 //===--------------------------------------------------------------------===//
247 /// SCEVCommutativeExpr - This node is the base class for n'ary commutative
250 class SCEVCommutativeExpr : public SCEVNAryExpr {
252 SCEVCommutativeExpr(const FoldingSetNodeIDRef ID,
253 enum SCEVTypes T, const SCEV *const *O, size_t N)
254 : SCEVNAryExpr(ID, T, O, N) {}
257 virtual const char *getOperationStr() const = 0;
259 virtual void print(raw_ostream &OS) const;
261 /// Methods for support type inquiry through isa, cast, and dyn_cast:
262 static inline bool classof(const SCEVCommutativeExpr *S) { return true; }
263 static inline bool classof(const SCEV *S) {
264 return S->getSCEVType() == scAddExpr ||
265 S->getSCEVType() == scMulExpr ||
266 S->getSCEVType() == scSMaxExpr ||
267 S->getSCEVType() == scUMaxExpr;
272 //===--------------------------------------------------------------------===//
273 /// SCEVAddExpr - This node represents an addition of some number of SCEVs.
275 class SCEVAddExpr : public SCEVCommutativeExpr {
276 friend class ScalarEvolution;
278 SCEVAddExpr(const FoldingSetNodeIDRef ID,
279 const SCEV *const *O, size_t N)
280 : SCEVCommutativeExpr(ID, scAddExpr, O, N) {
284 virtual bool hasComputableLoopEvolution(const Loop *QL) const {
285 // Not computable. An add of an addrec is always folded into the addrec
286 // if the other operands are loop-variant or loop-computable.
290 virtual const char *getOperationStr() const { return " + "; }
292 virtual const Type *getType() const {
293 // Use the type of the last operand, which is likely to be a pointer
294 // type, if there is one. This doesn't usually matter, but it can help
295 // reduce casts when the expressions are expanded.
296 return getOperand(getNumOperands() - 1)->getType();
299 /// Methods for support type inquiry through isa, cast, and dyn_cast:
300 static inline bool classof(const SCEVAddExpr *S) { return true; }
301 static inline bool classof(const SCEV *S) {
302 return S->getSCEVType() == scAddExpr;
306 //===--------------------------------------------------------------------===//
307 /// SCEVMulExpr - This node represents multiplication of some number of SCEVs.
309 class SCEVMulExpr : public SCEVCommutativeExpr {
310 friend class ScalarEvolution;
312 SCEVMulExpr(const FoldingSetNodeIDRef ID,
313 const SCEV *const *O, size_t N)
314 : SCEVCommutativeExpr(ID, scMulExpr, O, N) {
318 virtual bool hasComputableLoopEvolution(const Loop *QL) const {
319 // Not computable. A mul of an addrec is always folded into the addrec
320 // if the other operands are loop-variant or loop-computable.
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 FoldingSetNodeIDRef 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 FoldingSetNodeIDRef ID,
393 const SCEV *const *O, size_t N, const Loop *l)
394 : SCEVNAryExpr(ID, scAddRecExpr, O, N), L(l) {
395 for (size_t i = 0, e = NumOperands; 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 {
418 virtual bool isLoopInvariant(const Loop *QueryLoop) const;
420 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
422 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) 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 /// getPostIncExpr - Return an expression representing the value of
453 /// this expression one iteration of the loop ahead.
454 const SCEVAddRecExpr *getPostIncExpr(ScalarEvolution &SE) const {
455 return cast<SCEVAddRecExpr>(SE.getAddExpr(this, getStepRecurrence(SE)));
458 virtual void print(raw_ostream &OS) const;
460 /// Methods for support type inquiry through isa, cast, and dyn_cast:
461 static inline bool classof(const SCEVAddRecExpr *S) { return true; }
462 static inline bool classof(const SCEV *S) {
463 return S->getSCEVType() == scAddRecExpr;
468 //===--------------------------------------------------------------------===//
469 /// SCEVSMaxExpr - This class represents a signed maximum selection.
471 class SCEVSMaxExpr : public SCEVCommutativeExpr {
472 friend class ScalarEvolution;
474 SCEVSMaxExpr(const FoldingSetNodeIDRef ID,
475 const SCEV *const *O, size_t N)
476 : SCEVCommutativeExpr(ID, scSMaxExpr, O, N) {
477 // Max never overflows.
478 setHasNoUnsignedWrap(true);
479 setHasNoSignedWrap(true);
483 virtual const char *getOperationStr() const { return " smax "; }
485 /// Methods for support type inquiry through isa, cast, and dyn_cast:
486 static inline bool classof(const SCEVSMaxExpr *S) { return true; }
487 static inline bool classof(const SCEV *S) {
488 return S->getSCEVType() == scSMaxExpr;
493 //===--------------------------------------------------------------------===//
494 /// SCEVUMaxExpr - This class represents an unsigned maximum selection.
496 class SCEVUMaxExpr : public SCEVCommutativeExpr {
497 friend class ScalarEvolution;
499 SCEVUMaxExpr(const FoldingSetNodeIDRef ID,
500 const SCEV *const *O, size_t N)
501 : SCEVCommutativeExpr(ID, scUMaxExpr, O, N) {
502 // Max never overflows.
503 setHasNoUnsignedWrap(true);
504 setHasNoSignedWrap(true);
508 virtual const char *getOperationStr() const { return " umax "; }
510 /// Methods for support type inquiry through isa, cast, and dyn_cast:
511 static inline bool classof(const SCEVUMaxExpr *S) { return true; }
512 static inline bool classof(const SCEV *S) {
513 return S->getSCEVType() == scUMaxExpr;
517 //===--------------------------------------------------------------------===//
518 /// SCEVUnknown - This means that we are dealing with an entirely unknown SCEV
519 /// value, and only represent it as its LLVM Value. This is the "bottom"
520 /// value for the analysis.
522 class SCEVUnknown : public SCEV, private CallbackVH {
523 friend class ScalarEvolution;
525 // Implement CallbackVH.
526 virtual void deleted();
527 virtual void allUsesReplacedWith(Value *New);
529 /// SE - The parent ScalarEvolution value. This is used to update
530 /// the parent's maps when the value associated with a SCEVUnknown
531 /// is deleted or RAUW'd.
534 /// Next - The next pointer in the linked list of all
535 /// SCEVUnknown instances owned by a ScalarEvolution.
538 SCEVUnknown(const FoldingSetNodeIDRef ID, Value *V,
539 ScalarEvolution *se, SCEVUnknown *next) :
540 SCEV(ID, scUnknown), CallbackVH(V), SE(se), Next(next) {}
543 Value *getValue() const { return getValPtr(); }
545 /// isSizeOf, isAlignOf, isOffsetOf - Test whether this is a special
546 /// constant representing a type size, alignment, or field offset in
547 /// a target-independent manner, and hasn't happened to have been
548 /// folded with other operations into something unrecognizable. This
549 /// is mainly only useful for pretty-printing and other situations
550 /// where it isn't absolutely required for these to succeed.
551 bool isSizeOf(const Type *&AllocTy) const;
552 bool isAlignOf(const Type *&AllocTy) const;
553 bool isOffsetOf(const Type *&STy, Constant *&FieldNo) const;
555 virtual bool isLoopInvariant(const Loop *L) const;
556 virtual bool hasComputableLoopEvolution(const Loop *QL) const {
557 return false; // not computable
560 virtual bool hasOperand(const SCEV *) const {
564 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
566 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
568 virtual const Type *getType() const;
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 SCEVUnknown *S) { return true; }
574 static inline bool classof(const SCEV *S) {
575 return S->getSCEVType() == scUnknown;
579 /// SCEVVisitor - This class defines a simple visitor class that may be used
580 /// for various SCEV analysis purposes.
581 template<typename SC, typename RetVal=void>
583 RetVal visit(const SCEV *S) {
584 switch (S->getSCEVType()) {
586 return ((SC*)this)->visitConstant((const SCEVConstant*)S);
588 return ((SC*)this)->visitTruncateExpr((const SCEVTruncateExpr*)S);
590 return ((SC*)this)->visitZeroExtendExpr((const SCEVZeroExtendExpr*)S);
592 return ((SC*)this)->visitSignExtendExpr((const SCEVSignExtendExpr*)S);
594 return ((SC*)this)->visitAddExpr((const SCEVAddExpr*)S);
596 return ((SC*)this)->visitMulExpr((const SCEVMulExpr*)S);
598 return ((SC*)this)->visitUDivExpr((const SCEVUDivExpr*)S);
600 return ((SC*)this)->visitAddRecExpr((const SCEVAddRecExpr*)S);
602 return ((SC*)this)->visitSMaxExpr((const SCEVSMaxExpr*)S);
604 return ((SC*)this)->visitUMaxExpr((const SCEVUMaxExpr*)S);
606 return ((SC*)this)->visitUnknown((const SCEVUnknown*)S);
607 case scCouldNotCompute:
608 return ((SC*)this)->visitCouldNotCompute((const SCEVCouldNotCompute*)S);
610 llvm_unreachable("Unknown SCEV type!");
614 RetVal visitCouldNotCompute(const SCEVCouldNotCompute *S) {
615 llvm_unreachable("Invalid use of SCEVCouldNotCompute!");