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 /// 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 FoldingSetNodeIDRef 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 FoldingSetNodeIDRef 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 // Since SCEVs are immutable, ScalarEvolution allocates operand
184 // arrays with its SCEVAllocator, so this class just needs a simple
185 // pointer rather than a more elaborate vector-like data structure.
186 // This also avoids the need for a non-trivial destructor.
187 const SCEV *const *Operands;
190 SCEVNAryExpr(const FoldingSetNodeIDRef ID,
191 enum SCEVTypes T, const SCEV *const *O, size_t N)
192 : SCEV(ID, T), Operands(O), NumOperands(N) {}
195 size_t getNumOperands() const { return NumOperands; }
196 const SCEV *getOperand(unsigned i) const {
197 assert(i < NumOperands && "Operand index out of range!");
201 typedef const SCEV *const *op_iterator;
202 op_iterator op_begin() const { return Operands; }
203 op_iterator op_end() const { return Operands + NumOperands; }
205 virtual bool isLoopInvariant(const Loop *L) const;
207 // hasComputableLoopEvolution - N-ary expressions have computable loop
208 // evolutions iff they have at least one operand that varies with the loop,
209 // but that all varying operands are computable.
210 virtual bool hasComputableLoopEvolution(const Loop *L) const;
212 virtual bool hasOperand(const SCEV *O) const;
214 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
216 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
218 virtual const Type *getType() const { return getOperand(0)->getType(); }
220 bool hasNoUnsignedWrap() const { return SubclassData & (1 << 0); }
221 void setHasNoUnsignedWrap(bool B) {
222 SubclassData = (SubclassData & ~(1 << 0)) | (B << 0);
224 bool hasNoSignedWrap() const { return SubclassData & (1 << 1); }
225 void setHasNoSignedWrap(bool B) {
226 SubclassData = (SubclassData & ~(1 << 1)) | (B << 1);
229 /// Methods for support type inquiry through isa, cast, and dyn_cast:
230 static inline bool classof(const SCEVNAryExpr *S) { return true; }
231 static inline bool classof(const SCEV *S) {
232 return S->getSCEVType() == scAddExpr ||
233 S->getSCEVType() == scMulExpr ||
234 S->getSCEVType() == scSMaxExpr ||
235 S->getSCEVType() == scUMaxExpr ||
236 S->getSCEVType() == scAddRecExpr;
240 //===--------------------------------------------------------------------===//
241 /// SCEVCommutativeExpr - This node is the base class for n'ary commutative
244 class SCEVCommutativeExpr : public SCEVNAryExpr {
246 SCEVCommutativeExpr(const FoldingSetNodeIDRef ID,
247 enum SCEVTypes T, const SCEV *const *O, size_t N)
248 : SCEVNAryExpr(ID, T, O, N) {}
251 virtual const char *getOperationStr() const = 0;
253 virtual void print(raw_ostream &OS) const;
255 /// Methods for support type inquiry through isa, cast, and dyn_cast:
256 static inline bool classof(const SCEVCommutativeExpr *S) { return true; }
257 static inline bool classof(const SCEV *S) {
258 return S->getSCEVType() == scAddExpr ||
259 S->getSCEVType() == scMulExpr ||
260 S->getSCEVType() == scSMaxExpr ||
261 S->getSCEVType() == scUMaxExpr;
266 //===--------------------------------------------------------------------===//
267 /// SCEVAddExpr - This node represents an addition of some number of SCEVs.
269 class SCEVAddExpr : public SCEVCommutativeExpr {
270 friend class ScalarEvolution;
272 SCEVAddExpr(const FoldingSetNodeIDRef ID,
273 const SCEV *const *O, size_t N)
274 : SCEVCommutativeExpr(ID, scAddExpr, O, N) {
278 virtual const char *getOperationStr() const { return " + "; }
280 virtual const Type *getType() const {
281 // Use the type of the last operand, which is likely to be a pointer
282 // type, if there is one. This doesn't usually matter, but it can help
283 // reduce casts when the expressions are expanded.
284 return getOperand(getNumOperands() - 1)->getType();
287 /// Methods for support type inquiry through isa, cast, and dyn_cast:
288 static inline bool classof(const SCEVAddExpr *S) { return true; }
289 static inline bool classof(const SCEV *S) {
290 return S->getSCEVType() == scAddExpr;
294 //===--------------------------------------------------------------------===//
295 /// SCEVMulExpr - This node represents multiplication of some number of SCEVs.
297 class SCEVMulExpr : public SCEVCommutativeExpr {
298 friend class ScalarEvolution;
300 SCEVMulExpr(const FoldingSetNodeIDRef ID,
301 const SCEV *const *O, size_t N)
302 : SCEVCommutativeExpr(ID, scMulExpr, O, N) {
306 virtual const char *getOperationStr() const { return " * "; }
308 /// Methods for support type inquiry through isa, cast, and dyn_cast:
309 static inline bool classof(const SCEVMulExpr *S) { return true; }
310 static inline bool classof(const SCEV *S) {
311 return S->getSCEVType() == scMulExpr;
316 //===--------------------------------------------------------------------===//
317 /// SCEVUDivExpr - This class represents a binary unsigned division operation.
319 class SCEVUDivExpr : public SCEV {
320 friend class ScalarEvolution;
324 SCEVUDivExpr(const FoldingSetNodeIDRef ID, const SCEV *lhs, const SCEV *rhs)
325 : SCEV(ID, scUDivExpr), LHS(lhs), RHS(rhs) {}
328 const SCEV *getLHS() const { return LHS; }
329 const SCEV *getRHS() const { return RHS; }
331 virtual bool isLoopInvariant(const Loop *L) const {
332 return LHS->isLoopInvariant(L) && RHS->isLoopInvariant(L);
335 virtual bool hasComputableLoopEvolution(const Loop *L) const {
336 return LHS->hasComputableLoopEvolution(L) &&
337 RHS->hasComputableLoopEvolution(L);
340 virtual bool hasOperand(const SCEV *O) const {
341 return O == LHS || O == RHS || LHS->hasOperand(O) || RHS->hasOperand(O);
344 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
346 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
348 virtual const Type *getType() const;
350 void print(raw_ostream &OS) const;
352 /// Methods for support type inquiry through isa, cast, and dyn_cast:
353 static inline bool classof(const SCEVUDivExpr *S) { return true; }
354 static inline bool classof(const SCEV *S) {
355 return S->getSCEVType() == scUDivExpr;
360 //===--------------------------------------------------------------------===//
361 /// SCEVAddRecExpr - This node represents a polynomial recurrence on the trip
362 /// count of the specified loop. This is the primary focus of the
363 /// ScalarEvolution framework; all the other SCEV subclasses are mostly just
364 /// supporting infrastructure to allow SCEVAddRecExpr expressions to be
365 /// created and analyzed.
367 /// All operands of an AddRec are required to be loop invariant.
369 class SCEVAddRecExpr : public SCEVNAryExpr {
370 friend class ScalarEvolution;
374 SCEVAddRecExpr(const FoldingSetNodeIDRef ID,
375 const SCEV *const *O, size_t N, const Loop *l)
376 : SCEVNAryExpr(ID, scAddRecExpr, O, N), L(l) {
377 for (size_t i = 0, e = NumOperands; i != e; ++i)
378 assert(Operands[i]->isLoopInvariant(l) &&
379 "Operands of AddRec must be loop-invariant!");
383 const SCEV *getStart() const { return Operands[0]; }
384 const Loop *getLoop() const { return L; }
386 /// getStepRecurrence - This method constructs and returns the recurrence
387 /// indicating how much this expression steps by. If this is a polynomial
388 /// of degree N, it returns a chrec of degree N-1.
389 const SCEV *getStepRecurrence(ScalarEvolution &SE) const {
390 if (isAffine()) return getOperand(1);
391 return SE.getAddRecExpr(SmallVector<const SCEV *, 3>(op_begin()+1,
396 virtual bool hasComputableLoopEvolution(const Loop *QL) const {
400 virtual bool isLoopInvariant(const Loop *QueryLoop) const;
402 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
404 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
406 /// isAffine - Return true if this is an affine AddRec (i.e., it represents
407 /// an expressions A+B*x where A and B are loop invariant values.
408 bool isAffine() const {
409 // We know that the start value is invariant. This expression is thus
410 // affine iff the step is also invariant.
411 return getNumOperands() == 2;
414 /// isQuadratic - Return true if this is an quadratic AddRec (i.e., it
415 /// represents an expressions A+B*x+C*x^2 where A, B and C are loop
416 /// invariant values. This corresponds to an addrec of the form {L,+,M,+,N}
417 bool isQuadratic() const {
418 return getNumOperands() == 3;
421 /// evaluateAtIteration - Return the value of this chain of recurrences at
422 /// the specified iteration number.
423 const SCEV *evaluateAtIteration(const SCEV *It, ScalarEvolution &SE) const;
425 /// getNumIterationsInRange - Return the number of iterations of this loop
426 /// that produce values in the specified constant range. Another way of
427 /// looking at this is that it returns the first iteration number where the
428 /// value is not in the condition, thus computing the exit count. If the
429 /// iteration count can't be computed, an instance of SCEVCouldNotCompute is
431 const SCEV *getNumIterationsInRange(ConstantRange Range,
432 ScalarEvolution &SE) const;
434 /// getPostIncExpr - Return an expression representing the value of
435 /// this expression one iteration of the loop ahead.
436 const SCEVAddRecExpr *getPostIncExpr(ScalarEvolution &SE) const {
437 return cast<SCEVAddRecExpr>(SE.getAddExpr(this, getStepRecurrence(SE)));
440 virtual void print(raw_ostream &OS) const;
442 /// Methods for support type inquiry through isa, cast, and dyn_cast:
443 static inline bool classof(const SCEVAddRecExpr *S) { return true; }
444 static inline bool classof(const SCEV *S) {
445 return S->getSCEVType() == scAddRecExpr;
450 //===--------------------------------------------------------------------===//
451 /// SCEVSMaxExpr - This class represents a signed maximum selection.
453 class SCEVSMaxExpr : public SCEVCommutativeExpr {
454 friend class ScalarEvolution;
456 SCEVSMaxExpr(const FoldingSetNodeIDRef ID,
457 const SCEV *const *O, size_t N)
458 : SCEVCommutativeExpr(ID, scSMaxExpr, O, N) {
459 // Max never overflows.
460 setHasNoUnsignedWrap(true);
461 setHasNoSignedWrap(true);
465 virtual const char *getOperationStr() const { return " smax "; }
467 /// Methods for support type inquiry through isa, cast, and dyn_cast:
468 static inline bool classof(const SCEVSMaxExpr *S) { return true; }
469 static inline bool classof(const SCEV *S) {
470 return S->getSCEVType() == scSMaxExpr;
475 //===--------------------------------------------------------------------===//
476 /// SCEVUMaxExpr - This class represents an unsigned maximum selection.
478 class SCEVUMaxExpr : public SCEVCommutativeExpr {
479 friend class ScalarEvolution;
481 SCEVUMaxExpr(const FoldingSetNodeIDRef ID,
482 const SCEV *const *O, size_t N)
483 : SCEVCommutativeExpr(ID, scUMaxExpr, O, N) {
484 // Max never overflows.
485 setHasNoUnsignedWrap(true);
486 setHasNoSignedWrap(true);
490 virtual const char *getOperationStr() const { return " umax "; }
492 /// Methods for support type inquiry through isa, cast, and dyn_cast:
493 static inline bool classof(const SCEVUMaxExpr *S) { return true; }
494 static inline bool classof(const SCEV *S) {
495 return S->getSCEVType() == scUMaxExpr;
499 //===--------------------------------------------------------------------===//
500 /// SCEVUnknown - This means that we are dealing with an entirely unknown SCEV
501 /// value, and only represent it as its LLVM Value. This is the "bottom"
502 /// value for the analysis.
504 class SCEVUnknown : public SCEV, private CallbackVH {
505 friend class ScalarEvolution;
507 // Implement CallbackVH.
508 virtual void deleted();
509 virtual void allUsesReplacedWith(Value *New);
511 /// SE - The parent ScalarEvolution value. This is used to update
512 /// the parent's maps when the value associated with a SCEVUnknown
513 /// is deleted or RAUW'd.
516 /// Next - The next pointer in the linked list of all
517 /// SCEVUnknown instances owned by a ScalarEvolution.
520 SCEVUnknown(const FoldingSetNodeIDRef ID, Value *V,
521 ScalarEvolution *se, SCEVUnknown *next) :
522 SCEV(ID, scUnknown), CallbackVH(V), SE(se), Next(next) {}
525 Value *getValue() const { return getValPtr(); }
527 /// isSizeOf, isAlignOf, isOffsetOf - Test whether this is a special
528 /// constant representing a type size, alignment, or field offset in
529 /// a target-independent manner, and hasn't happened to have been
530 /// folded with other operations into something unrecognizable. This
531 /// is mainly only useful for pretty-printing and other situations
532 /// where it isn't absolutely required for these to succeed.
533 bool isSizeOf(const Type *&AllocTy) const;
534 bool isAlignOf(const Type *&AllocTy) const;
535 bool isOffsetOf(const Type *&STy, Constant *&FieldNo) const;
537 virtual bool isLoopInvariant(const Loop *L) const;
538 virtual bool hasComputableLoopEvolution(const Loop *QL) const {
539 return false; // not computable
542 virtual bool hasOperand(const SCEV *) const {
546 bool dominates(BasicBlock *BB, DominatorTree *DT) const;
548 bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
550 virtual const Type *getType() const;
552 virtual void print(raw_ostream &OS) const;
554 /// Methods for support type inquiry through isa, cast, and dyn_cast:
555 static inline bool classof(const SCEVUnknown *S) { return true; }
556 static inline bool classof(const SCEV *S) {
557 return S->getSCEVType() == scUnknown;
561 /// SCEVVisitor - This class defines a simple visitor class that may be used
562 /// for various SCEV analysis purposes.
563 template<typename SC, typename RetVal=void>
565 RetVal visit(const SCEV *S) {
566 switch (S->getSCEVType()) {
568 return ((SC*)this)->visitConstant((const SCEVConstant*)S);
570 return ((SC*)this)->visitTruncateExpr((const SCEVTruncateExpr*)S);
572 return ((SC*)this)->visitZeroExtendExpr((const SCEVZeroExtendExpr*)S);
574 return ((SC*)this)->visitSignExtendExpr((const SCEVSignExtendExpr*)S);
576 return ((SC*)this)->visitAddExpr((const SCEVAddExpr*)S);
578 return ((SC*)this)->visitMulExpr((const SCEVMulExpr*)S);
580 return ((SC*)this)->visitUDivExpr((const SCEVUDivExpr*)S);
582 return ((SC*)this)->visitAddRecExpr((const SCEVAddRecExpr*)S);
584 return ((SC*)this)->visitSMaxExpr((const SCEVSMaxExpr*)S);
586 return ((SC*)this)->visitUMaxExpr((const SCEVUMaxExpr*)S);
588 return ((SC*)this)->visitUnknown((const SCEVUnknown*)S);
589 case scCouldNotCompute:
590 return ((SC*)this)->visitCouldNotCompute((const SCEVCouldNotCompute*)S);
592 llvm_unreachable("Unknown SCEV type!");
596 RetVal visitCouldNotCompute(const SCEVCouldNotCompute *S) {
597 llvm_unreachable("Invalid use of SCEVCouldNotCompute!");