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_SCALAREVOLUTIONEXPRESSIONS_H
15 #define LLVM_ANALYSIS_SCALAREVOLUTIONEXPRESSIONS_H
17 #include "llvm/ADT/iterator_range.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/Analysis/ScalarEvolution.h"
20 #include "llvm/Support/ErrorHandling.h"
28 // These should be ordered in terms of increasing complexity to make the
30 scConstant, scTruncate, scZeroExtend, scSignExtend, scAddExpr, scMulExpr,
31 scUDivExpr, scAddRecExpr, scUMaxExpr, scSMaxExpr,
32 scUnknown, scCouldNotCompute
35 //===--------------------------------------------------------------------===//
36 /// SCEVConstant - This class represents a constant integer value.
38 class SCEVConstant : public SCEV {
39 friend class ScalarEvolution;
42 SCEVConstant(const FoldingSetNodeIDRef ID, ConstantInt *v) :
43 SCEV(ID, scConstant), V(v) {}
45 ConstantInt *getValue() const { return V; }
47 Type *getType() const { return V->getType(); }
49 /// Methods for support type inquiry through isa, cast, and dyn_cast:
50 static inline bool classof(const SCEV *S) {
51 return S->getSCEVType() == scConstant;
55 //===--------------------------------------------------------------------===//
56 /// SCEVCastExpr - This is the base class for unary cast operator classes.
58 class SCEVCastExpr : public SCEV {
63 SCEVCastExpr(const FoldingSetNodeIDRef ID,
64 unsigned SCEVTy, const SCEV *op, Type *ty);
67 const SCEV *getOperand() const { return Op; }
68 Type *getType() const { return Ty; }
70 /// Methods for support type inquiry through isa, cast, and dyn_cast:
71 static inline bool classof(const SCEV *S) {
72 return S->getSCEVType() == scTruncate ||
73 S->getSCEVType() == scZeroExtend ||
74 S->getSCEVType() == scSignExtend;
78 //===--------------------------------------------------------------------===//
79 /// SCEVTruncateExpr - This class represents a truncation of an integer value
80 /// to a smaller integer value.
82 class SCEVTruncateExpr : public SCEVCastExpr {
83 friend class ScalarEvolution;
85 SCEVTruncateExpr(const FoldingSetNodeIDRef ID,
86 const SCEV *op, Type *ty);
89 /// Methods for support type inquiry through isa, cast, and dyn_cast:
90 static inline bool classof(const SCEV *S) {
91 return S->getSCEVType() == scTruncate;
95 //===--------------------------------------------------------------------===//
96 /// SCEVZeroExtendExpr - This class represents a zero extension of a small
97 /// integer value to a larger integer value.
99 class SCEVZeroExtendExpr : public SCEVCastExpr {
100 friend class ScalarEvolution;
102 SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID,
103 const SCEV *op, Type *ty);
106 /// Methods for support type inquiry through isa, cast, and dyn_cast:
107 static inline bool classof(const SCEV *S) {
108 return S->getSCEVType() == scZeroExtend;
112 //===--------------------------------------------------------------------===//
113 /// SCEVSignExtendExpr - This class represents a sign extension of a small
114 /// integer value to a larger integer value.
116 class SCEVSignExtendExpr : public SCEVCastExpr {
117 friend class ScalarEvolution;
119 SCEVSignExtendExpr(const FoldingSetNodeIDRef ID,
120 const SCEV *op, Type *ty);
123 /// Methods for support type inquiry through isa, cast, and dyn_cast:
124 static inline bool classof(const SCEV *S) {
125 return S->getSCEVType() == scSignExtend;
130 //===--------------------------------------------------------------------===//
131 /// SCEVNAryExpr - This node is a base class providing common
132 /// functionality for n'ary operators.
134 class SCEVNAryExpr : public SCEV {
136 // Since SCEVs are immutable, ScalarEvolution allocates operand
137 // arrays with its SCEVAllocator, so this class just needs a simple
138 // pointer rather than a more elaborate vector-like data structure.
139 // This also avoids the need for a non-trivial destructor.
140 const SCEV *const *Operands;
143 SCEVNAryExpr(const FoldingSetNodeIDRef ID,
144 enum SCEVTypes T, const SCEV *const *O, size_t N)
145 : SCEV(ID, T), Operands(O), NumOperands(N) {}
148 size_t getNumOperands() const { return NumOperands; }
149 const SCEV *getOperand(unsigned i) const {
150 assert(i < NumOperands && "Operand index out of range!");
154 typedef const SCEV *const *op_iterator;
155 typedef iterator_range<op_iterator> op_range;
156 op_iterator op_begin() const { return Operands; }
157 op_iterator op_end() const { return Operands + NumOperands; }
158 op_range operands() const {
159 return make_range(op_begin(), op_end());
162 Type *getType() const { return getOperand(0)->getType(); }
164 NoWrapFlags getNoWrapFlags(NoWrapFlags Mask = NoWrapMask) const {
165 return (NoWrapFlags)(SubclassData & Mask);
168 /// Methods for support type inquiry through isa, cast, and dyn_cast:
169 static inline bool classof(const SCEV *S) {
170 return S->getSCEVType() == scAddExpr ||
171 S->getSCEVType() == scMulExpr ||
172 S->getSCEVType() == scSMaxExpr ||
173 S->getSCEVType() == scUMaxExpr ||
174 S->getSCEVType() == scAddRecExpr;
178 //===--------------------------------------------------------------------===//
179 /// SCEVCommutativeExpr - This node is the base class for n'ary commutative
182 class SCEVCommutativeExpr : public SCEVNAryExpr {
184 SCEVCommutativeExpr(const FoldingSetNodeIDRef ID,
185 enum SCEVTypes T, const SCEV *const *O, size_t N)
186 : SCEVNAryExpr(ID, T, O, N) {}
189 /// Methods for support type inquiry through isa, cast, and dyn_cast:
190 static inline bool classof(const SCEV *S) {
191 return S->getSCEVType() == scAddExpr ||
192 S->getSCEVType() == scMulExpr ||
193 S->getSCEVType() == scSMaxExpr ||
194 S->getSCEVType() == scUMaxExpr;
197 /// Set flags for a non-recurrence without clearing previously set flags.
198 void setNoWrapFlags(NoWrapFlags Flags) {
199 SubclassData |= Flags;
204 //===--------------------------------------------------------------------===//
205 /// SCEVAddExpr - This node represents an addition of some number of SCEVs.
207 class SCEVAddExpr : public SCEVCommutativeExpr {
208 friend class ScalarEvolution;
210 SCEVAddExpr(const FoldingSetNodeIDRef ID,
211 const SCEV *const *O, size_t N)
212 : SCEVCommutativeExpr(ID, scAddExpr, O, N) {
216 Type *getType() const {
217 // Use the type of the last operand, which is likely to be a pointer
218 // type, if there is one. This doesn't usually matter, but it can help
219 // reduce casts when the expressions are expanded.
220 return getOperand(getNumOperands() - 1)->getType();
223 /// Methods for support type inquiry through isa, cast, and dyn_cast:
224 static inline bool classof(const SCEV *S) {
225 return S->getSCEVType() == scAddExpr;
229 //===--------------------------------------------------------------------===//
230 /// SCEVMulExpr - This node represents multiplication of some number of SCEVs.
232 class SCEVMulExpr : public SCEVCommutativeExpr {
233 friend class ScalarEvolution;
235 SCEVMulExpr(const FoldingSetNodeIDRef ID,
236 const SCEV *const *O, size_t N)
237 : SCEVCommutativeExpr(ID, scMulExpr, O, N) {
241 /// Methods for support type inquiry through isa, cast, and dyn_cast:
242 static inline bool classof(const SCEV *S) {
243 return S->getSCEVType() == scMulExpr;
248 //===--------------------------------------------------------------------===//
249 /// SCEVUDivExpr - This class represents a binary unsigned division operation.
251 class SCEVUDivExpr : public SCEV {
252 friend class ScalarEvolution;
256 SCEVUDivExpr(const FoldingSetNodeIDRef ID, const SCEV *lhs, const SCEV *rhs)
257 : SCEV(ID, scUDivExpr), LHS(lhs), RHS(rhs) {}
260 const SCEV *getLHS() const { return LHS; }
261 const SCEV *getRHS() const { return RHS; }
263 Type *getType() const {
264 // In most cases the types of LHS and RHS will be the same, but in some
265 // crazy cases one or the other may be a pointer. ScalarEvolution doesn't
266 // depend on the type for correctness, but handling types carefully can
267 // avoid extra casts in the SCEVExpander. The LHS is more likely to be
268 // a pointer type than the RHS, so use the RHS' type here.
269 return getRHS()->getType();
272 /// Methods for support type inquiry through isa, cast, and dyn_cast:
273 static inline bool classof(const SCEV *S) {
274 return S->getSCEVType() == scUDivExpr;
279 //===--------------------------------------------------------------------===//
280 /// SCEVAddRecExpr - This node represents a polynomial recurrence on the trip
281 /// count of the specified loop. This is the primary focus of the
282 /// ScalarEvolution framework; all the other SCEV subclasses are mostly just
283 /// supporting infrastructure to allow SCEVAddRecExpr expressions to be
284 /// created and analyzed.
286 /// All operands of an AddRec are required to be loop invariant.
288 class SCEVAddRecExpr : public SCEVNAryExpr {
289 friend class ScalarEvolution;
293 SCEVAddRecExpr(const FoldingSetNodeIDRef ID,
294 const SCEV *const *O, size_t N, const Loop *l)
295 : SCEVNAryExpr(ID, scAddRecExpr, O, N), L(l) {}
298 const SCEV *getStart() const { return Operands[0]; }
299 const Loop *getLoop() const { return L; }
301 /// getStepRecurrence - This method constructs and returns the recurrence
302 /// indicating how much this expression steps by. If this is a polynomial
303 /// of degree N, it returns a chrec of degree N-1.
304 /// We cannot determine whether the step recurrence has self-wraparound.
305 const SCEV *getStepRecurrence(ScalarEvolution &SE) const {
306 if (isAffine()) return getOperand(1);
307 return SE.getAddRecExpr(SmallVector<const SCEV *, 3>(op_begin()+1,
309 getLoop(), FlagAnyWrap);
312 /// isAffine - Return true if this is an affine AddRec (i.e., it represents
313 /// an expressions A+B*x where A and B are loop invariant values.
314 bool isAffine() const {
315 // We know that the start value is invariant. This expression is thus
316 // affine iff the step is also invariant.
317 return getNumOperands() == 2;
320 /// isQuadratic - Return true if this is an quadratic AddRec (i.e., it
321 /// represents an expressions A+B*x+C*x^2 where A, B and C are loop
322 /// invariant values. This corresponds to an addrec of the form {L,+,M,+,N}
323 bool isQuadratic() const {
324 return getNumOperands() == 3;
327 /// Set flags for a recurrence without clearing any previously set flags.
328 /// For AddRec, either NUW or NSW implies NW. Keep track of this fact here
329 /// to make it easier to propagate flags.
330 void setNoWrapFlags(NoWrapFlags Flags) {
331 if (Flags & (FlagNUW | FlagNSW))
332 Flags = ScalarEvolution::setFlags(Flags, FlagNW);
333 SubclassData |= Flags;
336 /// evaluateAtIteration - Return the value of this chain of recurrences at
337 /// the specified iteration number.
338 const SCEV *evaluateAtIteration(const SCEV *It, ScalarEvolution &SE) const;
340 /// getNumIterationsInRange - Return the number of iterations of this loop
341 /// that produce values in the specified constant range. Another way of
342 /// looking at this is that it returns the first iteration number where the
343 /// value is not in the condition, thus computing the exit count. If the
344 /// iteration count can't be computed, an instance of SCEVCouldNotCompute is
346 const SCEV *getNumIterationsInRange(ConstantRange Range,
347 ScalarEvolution &SE) const;
349 /// getPostIncExpr - Return an expression representing the value of
350 /// this expression one iteration of the loop ahead.
351 const SCEVAddRecExpr *getPostIncExpr(ScalarEvolution &SE) const {
352 return cast<SCEVAddRecExpr>(SE.getAddExpr(this, getStepRecurrence(SE)));
355 /// Methods for support type inquiry through isa, cast, and dyn_cast:
356 static inline bool classof(const SCEV *S) {
357 return S->getSCEVType() == scAddRecExpr;
360 /// Collect parametric terms occurring in step expressions.
361 void collectParametricTerms(ScalarEvolution &SE,
362 SmallVectorImpl<const SCEV *> &Terms) const;
364 /// Return in Subscripts the access functions for each dimension in Sizes.
366 computeAccessFunctions(ScalarEvolution &SE,
367 SmallVectorImpl<const SCEV *> &Subscripts,
368 SmallVectorImpl<const SCEV *> &Sizes) const;
370 /// Split this SCEVAddRecExpr into two vectors of SCEVs representing the
371 /// subscripts and sizes of an array access. Returns the remainder of the
372 /// delinearization that is the offset start of the array.
374 /// The delinearization is a 3 step process: the first two steps compute the
375 /// sizes of each subscript and the third step computes the access functions
376 /// for the delinearized array:
378 /// 1. Find the terms in the step functions
379 /// 2. Compute the array size
380 /// 3. Compute the access function: divide the SCEV by the array size
381 /// starting with the innermost dimensions found in step 2. The Quotient
382 /// is the SCEV to be divided in the next step of the recursion. The
383 /// Remainder is the subscript of the innermost dimension. Loop over all
384 /// array dimensions computed in step 2.
386 /// To compute a uniform array size for several memory accesses to the same
387 /// object, one can collect in step 1 all the step terms for all the memory
388 /// accesses, and compute in step 2 a unique array shape. This guarantees
389 /// that the array shape will be the same across all memory accesses.
391 /// FIXME: We could derive the result of steps 1 and 2 from a description of
392 /// the array shape given in metadata.
403 /// The initial SCEV:
405 /// A[{{{0,+,2*m+5}_i, +, n*m}_j, +, n*m}_k]
407 /// 1. Find the different terms in the step functions:
408 /// -> [2*m, 5, n*m, n*m]
410 /// 2. Compute the array size: sort and unique them
412 /// find the GCD of all the terms = 1
413 /// divide by the GCD and erase constant terms
416 /// divide by GCD -> [n, 2]
417 /// remove constant terms
419 /// size of the array is A[unknown][n][m]
421 /// 3. Compute the access function
422 /// a. Divide {{{0,+,2*m+5}_i, +, n*m}_j, +, n*m}_k by the innermost size m
423 /// Quotient: {{{0,+,2}_i, +, n}_j, +, n}_k
424 /// Remainder: {{{0,+,5}_i, +, 0}_j, +, 0}_k
425 /// The remainder is the subscript of the innermost array dimension: [5i].
427 /// b. Divide Quotient: {{{0,+,2}_i, +, n}_j, +, n}_k by next outer size n
428 /// Quotient: {{{0,+,0}_i, +, 1}_j, +, 1}_k
429 /// Remainder: {{{0,+,2}_i, +, 0}_j, +, 0}_k
430 /// The Remainder is the subscript of the next array dimension: [2i].
432 /// The subscript of the outermost dimension is the Quotient: [j+k].
434 /// Overall, we have: A[][n][m], and the access function: A[j+k][2i][5i].
435 const SCEV *delinearize(ScalarEvolution &SE,
436 SmallVectorImpl<const SCEV *> &Subscripts,
437 SmallVectorImpl<const SCEV *> &Sizes,
438 const SCEV *ElementSize) const;
441 //===--------------------------------------------------------------------===//
442 /// SCEVSMaxExpr - This class represents a signed maximum selection.
444 class SCEVSMaxExpr : public SCEVCommutativeExpr {
445 friend class ScalarEvolution;
447 SCEVSMaxExpr(const FoldingSetNodeIDRef ID,
448 const SCEV *const *O, size_t N)
449 : SCEVCommutativeExpr(ID, scSMaxExpr, O, N) {
450 // Max never overflows.
451 setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW));
455 /// Methods for support type inquiry through isa, cast, and dyn_cast:
456 static inline bool classof(const SCEV *S) {
457 return S->getSCEVType() == scSMaxExpr;
462 //===--------------------------------------------------------------------===//
463 /// SCEVUMaxExpr - This class represents an unsigned maximum selection.
465 class SCEVUMaxExpr : public SCEVCommutativeExpr {
466 friend class ScalarEvolution;
468 SCEVUMaxExpr(const FoldingSetNodeIDRef ID,
469 const SCEV *const *O, size_t N)
470 : SCEVCommutativeExpr(ID, scUMaxExpr, O, N) {
471 // Max never overflows.
472 setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW));
476 /// Methods for support type inquiry through isa, cast, and dyn_cast:
477 static inline bool classof(const SCEV *S) {
478 return S->getSCEVType() == scUMaxExpr;
482 //===--------------------------------------------------------------------===//
483 /// SCEVUnknown - This means that we are dealing with an entirely unknown SCEV
484 /// value, and only represent it as its LLVM Value. This is the "bottom"
485 /// value for the analysis.
487 class SCEVUnknown : public SCEV, private CallbackVH {
488 friend class ScalarEvolution;
490 // Implement CallbackVH.
491 void deleted() override;
492 void allUsesReplacedWith(Value *New) override;
494 /// SE - The parent ScalarEvolution value. This is used to update
495 /// the parent's maps when the value associated with a SCEVUnknown
496 /// is deleted or RAUW'd.
499 /// Next - The next pointer in the linked list of all
500 /// SCEVUnknown instances owned by a ScalarEvolution.
503 SCEVUnknown(const FoldingSetNodeIDRef ID, Value *V,
504 ScalarEvolution *se, SCEVUnknown *next) :
505 SCEV(ID, scUnknown), CallbackVH(V), SE(se), Next(next) {}
508 Value *getValue() const { return getValPtr(); }
510 /// isSizeOf, isAlignOf, isOffsetOf - Test whether this is a special
511 /// constant representing a type size, alignment, or field offset in
512 /// a target-independent manner, and hasn't happened to have been
513 /// folded with other operations into something unrecognizable. This
514 /// is mainly only useful for pretty-printing and other situations
515 /// where it isn't absolutely required for these to succeed.
516 bool isSizeOf(Type *&AllocTy) const;
517 bool isAlignOf(Type *&AllocTy) const;
518 bool isOffsetOf(Type *&STy, Constant *&FieldNo) const;
520 Type *getType() const { return getValPtr()->getType(); }
522 /// Methods for support type inquiry through isa, cast, and dyn_cast:
523 static inline bool classof(const SCEV *S) {
524 return S->getSCEVType() == scUnknown;
528 /// SCEVVisitor - This class defines a simple visitor class that may be used
529 /// for various SCEV analysis purposes.
530 template<typename SC, typename RetVal=void>
532 RetVal visit(const SCEV *S) {
533 switch (S->getSCEVType()) {
535 return ((SC*)this)->visitConstant((const SCEVConstant*)S);
537 return ((SC*)this)->visitTruncateExpr((const SCEVTruncateExpr*)S);
539 return ((SC*)this)->visitZeroExtendExpr((const SCEVZeroExtendExpr*)S);
541 return ((SC*)this)->visitSignExtendExpr((const SCEVSignExtendExpr*)S);
543 return ((SC*)this)->visitAddExpr((const SCEVAddExpr*)S);
545 return ((SC*)this)->visitMulExpr((const SCEVMulExpr*)S);
547 return ((SC*)this)->visitUDivExpr((const SCEVUDivExpr*)S);
549 return ((SC*)this)->visitAddRecExpr((const SCEVAddRecExpr*)S);
551 return ((SC*)this)->visitSMaxExpr((const SCEVSMaxExpr*)S);
553 return ((SC*)this)->visitUMaxExpr((const SCEVUMaxExpr*)S);
555 return ((SC*)this)->visitUnknown((const SCEVUnknown*)S);
556 case scCouldNotCompute:
557 return ((SC*)this)->visitCouldNotCompute((const SCEVCouldNotCompute*)S);
559 llvm_unreachable("Unknown SCEV type!");
563 RetVal visitCouldNotCompute(const SCEVCouldNotCompute *S) {
564 llvm_unreachable("Invalid use of SCEVCouldNotCompute!");
568 /// Visit all nodes in the expression tree using worklist traversal.
570 /// Visitor implements:
571 /// // return true to follow this node.
572 /// bool follow(const SCEV *S);
573 /// // return true to terminate the search.
575 template<typename SV>
576 class SCEVTraversal {
578 SmallVector<const SCEV *, 8> Worklist;
579 SmallPtrSet<const SCEV *, 8> Visited;
581 void push(const SCEV *S) {
582 if (Visited.insert(S) && Visitor.follow(S))
583 Worklist.push_back(S);
586 SCEVTraversal(SV& V): Visitor(V) {}
588 void visitAll(const SCEV *Root) {
590 while (!Worklist.empty() && !Visitor.isDone()) {
591 const SCEV *S = Worklist.pop_back_val();
593 switch (S->getSCEVType()) {
600 push(cast<SCEVCastExpr>(S)->getOperand());
607 const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(S);
608 for (SCEVNAryExpr::op_iterator I = NAry->op_begin(),
609 E = NAry->op_end(); I != E; ++I) {
615 const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S);
616 push(UDiv->getLHS());
617 push(UDiv->getRHS());
620 case scCouldNotCompute:
621 llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
623 llvm_unreachable("Unknown SCEV kind!");
629 /// Use SCEVTraversal to visit all nodes in the givien expression tree.
630 template<typename SV>
631 void visitAll(const SCEV *Root, SV& Visitor) {
632 SCEVTraversal<SV> T(Visitor);
636 typedef DenseMap<const Value*, Value*> ValueToValueMap;
638 /// The SCEVParameterRewriter takes a scalar evolution expression and updates
639 /// the SCEVUnknown components following the Map (Value -> Value).
640 struct SCEVParameterRewriter
641 : public SCEVVisitor<SCEVParameterRewriter, const SCEV*> {
643 static const SCEV *rewrite(const SCEV *Scev, ScalarEvolution &SE,
644 ValueToValueMap &Map,
645 bool InterpretConsts = false) {
646 SCEVParameterRewriter Rewriter(SE, Map, InterpretConsts);
647 return Rewriter.visit(Scev);
650 SCEVParameterRewriter(ScalarEvolution &S, ValueToValueMap &M, bool C)
651 : SE(S), Map(M), InterpretConsts(C) {}
653 const SCEV *visitConstant(const SCEVConstant *Constant) {
657 const SCEV *visitTruncateExpr(const SCEVTruncateExpr *Expr) {
658 const SCEV *Operand = visit(Expr->getOperand());
659 return SE.getTruncateExpr(Operand, Expr->getType());
662 const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *Expr) {
663 const SCEV *Operand = visit(Expr->getOperand());
664 return SE.getZeroExtendExpr(Operand, Expr->getType());
667 const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) {
668 const SCEV *Operand = visit(Expr->getOperand());
669 return SE.getSignExtendExpr(Operand, Expr->getType());
672 const SCEV *visitAddExpr(const SCEVAddExpr *Expr) {
673 SmallVector<const SCEV *, 2> Operands;
674 for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
675 Operands.push_back(visit(Expr->getOperand(i)));
676 return SE.getAddExpr(Operands);
679 const SCEV *visitMulExpr(const SCEVMulExpr *Expr) {
680 SmallVector<const SCEV *, 2> Operands;
681 for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
682 Operands.push_back(visit(Expr->getOperand(i)));
683 return SE.getMulExpr(Operands);
686 const SCEV *visitUDivExpr(const SCEVUDivExpr *Expr) {
687 return SE.getUDivExpr(visit(Expr->getLHS()), visit(Expr->getRHS()));
690 const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
691 SmallVector<const SCEV *, 2> Operands;
692 for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
693 Operands.push_back(visit(Expr->getOperand(i)));
694 return SE.getAddRecExpr(Operands, Expr->getLoop(),
695 Expr->getNoWrapFlags());
698 const SCEV *visitSMaxExpr(const SCEVSMaxExpr *Expr) {
699 SmallVector<const SCEV *, 2> Operands;
700 for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
701 Operands.push_back(visit(Expr->getOperand(i)));
702 return SE.getSMaxExpr(Operands);
705 const SCEV *visitUMaxExpr(const SCEVUMaxExpr *Expr) {
706 SmallVector<const SCEV *, 2> Operands;
707 for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
708 Operands.push_back(visit(Expr->getOperand(i)));
709 return SE.getUMaxExpr(Operands);
712 const SCEV *visitUnknown(const SCEVUnknown *Expr) {
713 Value *V = Expr->getValue();
716 if (InterpretConsts && isa<ConstantInt>(NV))
717 return SE.getConstant(cast<ConstantInt>(NV));
718 return SE.getUnknown(NV);
723 const SCEV *visitCouldNotCompute(const SCEVCouldNotCompute *Expr) {
729 ValueToValueMap ⤅
730 bool InterpretConsts;
733 typedef DenseMap<const Loop*, const SCEV*> LoopToScevMapT;
735 /// The SCEVApplyRewriter takes a scalar evolution expression and applies
736 /// the Map (Loop -> SCEV) to all AddRecExprs.
737 struct SCEVApplyRewriter
738 : public SCEVVisitor<SCEVApplyRewriter, const SCEV*> {
740 static const SCEV *rewrite(const SCEV *Scev, LoopToScevMapT &Map,
741 ScalarEvolution &SE) {
742 SCEVApplyRewriter Rewriter(SE, Map);
743 return Rewriter.visit(Scev);
746 SCEVApplyRewriter(ScalarEvolution &S, LoopToScevMapT &M)
749 const SCEV *visitConstant(const SCEVConstant *Constant) {
753 const SCEV *visitTruncateExpr(const SCEVTruncateExpr *Expr) {
754 const SCEV *Operand = visit(Expr->getOperand());
755 return SE.getTruncateExpr(Operand, Expr->getType());
758 const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *Expr) {
759 const SCEV *Operand = visit(Expr->getOperand());
760 return SE.getZeroExtendExpr(Operand, Expr->getType());
763 const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) {
764 const SCEV *Operand = visit(Expr->getOperand());
765 return SE.getSignExtendExpr(Operand, Expr->getType());
768 const SCEV *visitAddExpr(const SCEVAddExpr *Expr) {
769 SmallVector<const SCEV *, 2> Operands;
770 for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
771 Operands.push_back(visit(Expr->getOperand(i)));
772 return SE.getAddExpr(Operands);
775 const SCEV *visitMulExpr(const SCEVMulExpr *Expr) {
776 SmallVector<const SCEV *, 2> Operands;
777 for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
778 Operands.push_back(visit(Expr->getOperand(i)));
779 return SE.getMulExpr(Operands);
782 const SCEV *visitUDivExpr(const SCEVUDivExpr *Expr) {
783 return SE.getUDivExpr(visit(Expr->getLHS()), visit(Expr->getRHS()));
786 const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
787 SmallVector<const SCEV *, 2> Operands;
788 for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
789 Operands.push_back(visit(Expr->getOperand(i)));
791 const Loop *L = Expr->getLoop();
792 const SCEV *Res = SE.getAddRecExpr(Operands, L, Expr->getNoWrapFlags());
794 if (0 == Map.count(L))
797 const SCEVAddRecExpr *Rec = (const SCEVAddRecExpr *) Res;
798 return Rec->evaluateAtIteration(Map[L], SE);
801 const SCEV *visitSMaxExpr(const SCEVSMaxExpr *Expr) {
802 SmallVector<const SCEV *, 2> Operands;
803 for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
804 Operands.push_back(visit(Expr->getOperand(i)));
805 return SE.getSMaxExpr(Operands);
808 const SCEV *visitUMaxExpr(const SCEVUMaxExpr *Expr) {
809 SmallVector<const SCEV *, 2> Operands;
810 for (int i = 0, e = Expr->getNumOperands(); i < e; ++i)
811 Operands.push_back(visit(Expr->getOperand(i)));
812 return SE.getUMaxExpr(Operands);
815 const SCEV *visitUnknown(const SCEVUnknown *Expr) {
819 const SCEV *visitCouldNotCompute(const SCEVCouldNotCompute *Expr) {
828 /// Applies the Map (Loop -> SCEV) to the given Scev.
829 static inline const SCEV *apply(const SCEV *Scev, LoopToScevMapT &Map,
830 ScalarEvolution &SE) {
831 return SCEVApplyRewriter::rewrite(Scev, Map, SE);