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DependenceAnalysis.h
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1 //===-- llvm/Analysis/DependenceAnalysis.h -------------------- -*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // DependenceAnalysis is an LLVM pass that analyses dependences between memory
10 // accesses. Currently, it is an implementation of the approach described in
11 //
12 // Practical Dependence Testing
13 // Goff, Kennedy, Tseng
14 // PLDI 1991
15 //
16 // There's a single entry point that analyzes the dependence between a pair
17 // of memory references in a function, returning either NULL, for no dependence,
18 // or a more-or-less detailed description of the dependence between them.
19 //
20 // This pass exists to support the DependenceGraph pass. There are two separate
21 // passes because there's a useful separation of concerns. A dependence exists
22 // if two conditions are met:
23 //
24 // 1) Two instructions reference the same memory location, and
25 // 2) There is a flow of control leading from one instruction to the other.
26 //
27 // DependenceAnalysis attacks the first condition; DependenceGraph will attack
28 // the second (it's not yet ready).
29 //
30 // Please note that this is work in progress and the interface is subject to
31 // change.
32 //
33 // Plausible changes:
34 // Return a set of more precise dependences instead of just one dependence
35 // summarizing all.
36 //
37 //===----------------------------------------------------------------------===//
38 
39 #ifndef LLVM_ANALYSIS_DEPENDENCEANALYSIS_H
40 #define LLVM_ANALYSIS_DEPENDENCEANALYSIS_H
41 
43 #include "llvm/IR/Instructions.h"
44 #include "llvm/IR/PassManager.h"
45 #include "llvm/Pass.h"
46 
47 namespace llvm {
48  class AAResults;
49  template <typename T> class ArrayRef;
50  class Loop;
51  class LoopInfo;
52  class ScalarEvolution;
53  class SCEV;
54  class SCEVConstant;
55  class raw_ostream;
56 
57  /// Dependence - This class represents a dependence between two memory
58  /// memory references in a function. It contains minimal information and
59  /// is used in the very common situation where the compiler is unable to
60  /// determine anything beyond the existence of a dependence; that is, it
61  /// represents a confused dependence (see also FullDependence). In most
62  /// cases (for output, flow, and anti dependences), the dependence implies
63  /// an ordering, where the source must precede the destination; in contrast,
64  /// input dependences are unordered.
65  ///
66  /// When a dependence graph is built, each Dependence will be a member of
67  /// the set of predecessor edges for its destination instruction and a set
68  /// if successor edges for its source instruction. These sets are represented
69  /// as singly-linked lists, with the "next" fields stored in the dependence
70  /// itelf.
71  class Dependence {
72  protected:
73  Dependence(Dependence &&) = default;
74  Dependence &operator=(Dependence &&) = default;
75 
76  public:
78  : Src(Source), Dst(Destination) {}
79  virtual ~Dependence() = default;
80 
81  /// Dependence::DVEntry - Each level in the distance/direction vector
82  /// has a direction (or perhaps a union of several directions), and
83  /// perhaps a distance.
84  struct DVEntry {
85  enum { NONE = 0,
86  LT = 1,
87  EQ = 2,
88  LE = 3,
89  GT = 4,
90  NE = 5,
91  GE = 6,
92  ALL = 7 };
93  unsigned char Direction : 3; // Init to ALL, then refine.
94  bool Scalar : 1; // Init to true.
95  bool PeelFirst : 1; // Peeling the first iteration will break dependence.
96  bool PeelLast : 1; // Peeling the last iteration will break the dependence.
97  bool Splitable : 1; // Splitting the loop will break dependence.
98  const SCEV *Distance = nullptr; // NULL implies no distance available.
101  Splitable(false) {}
102  };
103 
104  /// getSrc - Returns the source instruction for this dependence.
105  ///
106  Instruction *getSrc() const { return Src; }
107 
108  /// getDst - Returns the destination instruction for this dependence.
109  ///
110  Instruction *getDst() const { return Dst; }
111 
112  /// isInput - Returns true if this is an input dependence.
113  ///
114  bool isInput() const;
115 
116  /// isOutput - Returns true if this is an output dependence.
117  ///
118  bool isOutput() const;
119 
120  /// isFlow - Returns true if this is a flow (aka true) dependence.
121  ///
122  bool isFlow() const;
123 
124  /// isAnti - Returns true if this is an anti dependence.
125  ///
126  bool isAnti() const;
127 
128  /// isOrdered - Returns true if dependence is Output, Flow, or Anti
129  ///
130  bool isOrdered() const { return isOutput() || isFlow() || isAnti(); }
131 
132  /// isUnordered - Returns true if dependence is Input
133  ///
134  bool isUnordered() const { return isInput(); }
135 
136  /// isLoopIndependent - Returns true if this is a loop-independent
137  /// dependence.
138  virtual bool isLoopIndependent() const { return true; }
139 
140  /// isConfused - Returns true if this dependence is confused
141  /// (the compiler understands nothing and makes worst-case
142  /// assumptions).
143  virtual bool isConfused() const { return true; }
144 
145  /// isConsistent - Returns true if this dependence is consistent
146  /// (occurs every time the source and destination are executed).
147  virtual bool isConsistent() const { return false; }
148 
149  /// getLevels - Returns the number of common loops surrounding the
150  /// source and destination of the dependence.
151  virtual unsigned getLevels() const { return 0; }
152 
153  /// getDirection - Returns the direction associated with a particular
154  /// level.
155  virtual unsigned getDirection(unsigned Level) const { return DVEntry::ALL; }
156 
157  /// getDistance - Returns the distance (or NULL) associated with a
158  /// particular level.
159  virtual const SCEV *getDistance(unsigned Level) const { return nullptr; }
160 
161  /// isPeelFirst - Returns true if peeling the first iteration from
162  /// this loop will break this dependence.
163  virtual bool isPeelFirst(unsigned Level) const { return false; }
164 
165  /// isPeelLast - Returns true if peeling the last iteration from
166  /// this loop will break this dependence.
167  virtual bool isPeelLast(unsigned Level) const { return false; }
168 
169  /// isSplitable - Returns true if splitting this loop will break
170  /// the dependence.
171  virtual bool isSplitable(unsigned Level) const { return false; }
172 
173  /// isScalar - Returns true if a particular level is scalar; that is,
174  /// if no subscript in the source or destination mention the induction
175  /// variable associated with the loop at this level.
176  virtual bool isScalar(unsigned Level) const;
177 
178  /// getNextPredecessor - Returns the value of the NextPredecessor
179  /// field.
180  const Dependence *getNextPredecessor() const { return NextPredecessor; }
181 
182  /// getNextSuccessor - Returns the value of the NextSuccessor
183  /// field.
184  const Dependence *getNextSuccessor() const { return NextSuccessor; }
185 
186  /// setNextPredecessor - Sets the value of the NextPredecessor
187  /// field.
188  void setNextPredecessor(const Dependence *pred) { NextPredecessor = pred; }
189 
190  /// setNextSuccessor - Sets the value of the NextSuccessor
191  /// field.
192  void setNextSuccessor(const Dependence *succ) { NextSuccessor = succ; }
193 
194  /// dump - For debugging purposes, dumps a dependence to OS.
195  ///
196  void dump(raw_ostream &OS) const;
197 
198  private:
199  Instruction *Src, *Dst;
200  const Dependence *NextPredecessor = nullptr, *NextSuccessor = nullptr;
201  friend class DependenceInfo;
202  };
203 
204  /// FullDependence - This class represents a dependence between two memory
205  /// references in a function. It contains detailed information about the
206  /// dependence (direction vectors, etc.) and is used when the compiler is
207  /// able to accurately analyze the interaction of the references; that is,
208  /// it is not a confused dependence (see Dependence). In most cases
209  /// (for output, flow, and anti dependences), the dependence implies an
210  /// ordering, where the source must precede the destination; in contrast,
211  /// input dependences are unordered.
212  class FullDependence final : public Dependence {
213  public:
214  FullDependence(Instruction *Src, Instruction *Dst, bool LoopIndependent,
215  unsigned Levels);
216 
217  /// isLoopIndependent - Returns true if this is a loop-independent
218  /// dependence.
219  bool isLoopIndependent() const override { return LoopIndependent; }
220 
221  /// isConfused - Returns true if this dependence is confused
222  /// (the compiler understands nothing and makes worst-case
223  /// assumptions).
224  bool isConfused() const override { return false; }
225 
226  /// isConsistent - Returns true if this dependence is consistent
227  /// (occurs every time the source and destination are executed).
228  bool isConsistent() const override { return Consistent; }
229 
230  /// getLevels - Returns the number of common loops surrounding the
231  /// source and destination of the dependence.
232  unsigned getLevels() const override { return Levels; }
233 
234  /// getDirection - Returns the direction associated with a particular
235  /// level.
236  unsigned getDirection(unsigned Level) const override;
237 
238  /// getDistance - Returns the distance (or NULL) associated with a
239  /// particular level.
240  const SCEV *getDistance(unsigned Level) const override;
241 
242  /// isPeelFirst - Returns true if peeling the first iteration from
243  /// this loop will break this dependence.
244  bool isPeelFirst(unsigned Level) const override;
245 
246  /// isPeelLast - Returns true if peeling the last iteration from
247  /// this loop will break this dependence.
248  bool isPeelLast(unsigned Level) const override;
249 
250  /// isSplitable - Returns true if splitting the loop will break
251  /// the dependence.
252  bool isSplitable(unsigned Level) const override;
253 
254  /// isScalar - Returns true if a particular level is scalar; that is,
255  /// if no subscript in the source or destination mention the induction
256  /// variable associated with the loop at this level.
257  bool isScalar(unsigned Level) const override;
258 
259  private:
260  unsigned short Levels;
261  bool LoopIndependent;
262  bool Consistent; // Init to true, then refine.
263  std::unique_ptr<DVEntry[]> DV;
264  friend class DependenceInfo;
265  };
266 
267  /// DependenceInfo - This class is the main dependence-analysis driver.
268  ///
270  public:
272  LoopInfo *LI)
273  : AA(AA), SE(SE), LI(LI), F(F) {}
274 
275  /// Handle transitive invalidation when the cached analysis results go away.
276  bool invalidate(Function &F, const PreservedAnalyses &PA,
278 
279  /// depends - Tests for a dependence between the Src and Dst instructions.
280  /// Returns NULL if no dependence; otherwise, returns a Dependence (or a
281  /// FullDependence) with as much information as can be gleaned.
282  /// The flag PossiblyLoopIndependent should be set by the caller
283  /// if it appears that control flow can reach from Src to Dst
284  /// without traversing a loop back edge.
285  std::unique_ptr<Dependence> depends(Instruction *Src,
286  Instruction *Dst,
287  bool PossiblyLoopIndependent);
288 
289  /// getSplitIteration - Give a dependence that's splittable at some
290  /// particular level, return the iteration that should be used to split
291  /// the loop.
292  ///
293  /// Generally, the dependence analyzer will be used to build
294  /// a dependence graph for a function (basically a map from instructions
295  /// to dependences). Looking for cycles in the graph shows us loops
296  /// that cannot be trivially vectorized/parallelized.
297  ///
298  /// We can try to improve the situation by examining all the dependences
299  /// that make up the cycle, looking for ones we can break.
300  /// Sometimes, peeling the first or last iteration of a loop will break
301  /// dependences, and there are flags for those possibilities.
302  /// Sometimes, splitting a loop at some other iteration will do the trick,
303  /// and we've got a flag for that case. Rather than waste the space to
304  /// record the exact iteration (since we rarely know), we provide
305  /// a method that calculates the iteration. It's a drag that it must work
306  /// from scratch, but wonderful in that it's possible.
307  ///
308  /// Here's an example:
309  ///
310  /// for (i = 0; i < 10; i++)
311  /// A[i] = ...
312  /// ... = A[11 - i]
313  ///
314  /// There's a loop-carried flow dependence from the store to the load,
315  /// found by the weak-crossing SIV test. The dependence will have a flag,
316  /// indicating that the dependence can be broken by splitting the loop.
317  /// Calling getSplitIteration will return 5.
318  /// Splitting the loop breaks the dependence, like so:
319  ///
320  /// for (i = 0; i <= 5; i++)
321  /// A[i] = ...
322  /// ... = A[11 - i]
323  /// for (i = 6; i < 10; i++)
324  /// A[i] = ...
325  /// ... = A[11 - i]
326  ///
327  /// breaks the dependence and allows us to vectorize/parallelize
328  /// both loops.
329  const SCEV *getSplitIteration(const Dependence &Dep, unsigned Level);
330 
331  Function *getFunction() const { return F; }
332 
333  private:
334  AAResults *AA;
335  ScalarEvolution *SE;
336  LoopInfo *LI;
337  Function *F;
338 
339  /// Subscript - This private struct represents a pair of subscripts from
340  /// a pair of potentially multi-dimensional array references. We use a
341  /// vector of them to guide subscript partitioning.
342  struct Subscript {
343  const SCEV *Src;
344  const SCEV *Dst;
345  enum ClassificationKind { ZIV, SIV, RDIV, MIV, NonLinear } Classification;
346  SmallBitVector Loops;
347  SmallBitVector GroupLoops;
348  SmallBitVector Group;
349  };
350 
351  struct CoefficientInfo {
352  const SCEV *Coeff;
353  const SCEV *PosPart;
354  const SCEV *NegPart;
355  const SCEV *Iterations;
356  };
357 
358  struct BoundInfo {
359  const SCEV *Iterations;
360  const SCEV *Upper[8];
361  const SCEV *Lower[8];
362  unsigned char Direction;
363  unsigned char DirSet;
364  };
365 
366  /// Constraint - This private class represents a constraint, as defined
367  /// in the paper
368  ///
369  /// Practical Dependence Testing
370  /// Goff, Kennedy, Tseng
371  /// PLDI 1991
372  ///
373  /// There are 5 kinds of constraint, in a hierarchy.
374  /// 1) Any - indicates no constraint, any dependence is possible.
375  /// 2) Line - A line ax + by = c, where a, b, and c are parameters,
376  /// representing the dependence equation.
377  /// 3) Distance - The value d of the dependence distance;
378  /// 4) Point - A point <x, y> representing the dependence from
379  /// iteration x to iteration y.
380  /// 5) Empty - No dependence is possible.
381  class Constraint {
382  private:
383  enum ConstraintKind { Empty, Point, Distance, Line, Any } Kind;
384  ScalarEvolution *SE;
385  const SCEV *A;
386  const SCEV *B;
387  const SCEV *C;
388  const Loop *AssociatedLoop;
389 
390  public:
391  /// isEmpty - Return true if the constraint is of kind Empty.
392  bool isEmpty() const { return Kind == Empty; }
393 
394  /// isPoint - Return true if the constraint is of kind Point.
395  bool isPoint() const { return Kind == Point; }
396 
397  /// isDistance - Return true if the constraint is of kind Distance.
398  bool isDistance() const { return Kind == Distance; }
399 
400  /// isLine - Return true if the constraint is of kind Line.
401  /// Since Distance's can also be represented as Lines, we also return
402  /// true if the constraint is of kind Distance.
403  bool isLine() const { return Kind == Line || Kind == Distance; }
404 
405  /// isAny - Return true if the constraint is of kind Any;
406  bool isAny() const { return Kind == Any; }
407 
408  /// getX - If constraint is a point <X, Y>, returns X.
409  /// Otherwise assert.
410  const SCEV *getX() const;
411 
412  /// getY - If constraint is a point <X, Y>, returns Y.
413  /// Otherwise assert.
414  const SCEV *getY() const;
415 
416  /// getA - If constraint is a line AX + BY = C, returns A.
417  /// Otherwise assert.
418  const SCEV *getA() const;
419 
420  /// getB - If constraint is a line AX + BY = C, returns B.
421  /// Otherwise assert.
422  const SCEV *getB() const;
423 
424  /// getC - If constraint is a line AX + BY = C, returns C.
425  /// Otherwise assert.
426  const SCEV *getC() const;
427 
428  /// getD - If constraint is a distance, returns D.
429  /// Otherwise assert.
430  const SCEV *getD() const;
431 
432  /// getAssociatedLoop - Returns the loop associated with this constraint.
433  const Loop *getAssociatedLoop() const;
434 
435  /// setPoint - Change a constraint to Point.
436  void setPoint(const SCEV *X, const SCEV *Y, const Loop *CurrentLoop);
437 
438  /// setLine - Change a constraint to Line.
439  void setLine(const SCEV *A, const SCEV *B,
440  const SCEV *C, const Loop *CurrentLoop);
441 
442  /// setDistance - Change a constraint to Distance.
443  void setDistance(const SCEV *D, const Loop *CurrentLoop);
444 
445  /// setEmpty - Change a constraint to Empty.
446  void setEmpty();
447 
448  /// setAny - Change a constraint to Any.
449  void setAny(ScalarEvolution *SE);
450 
451  /// dump - For debugging purposes. Dumps the constraint
452  /// out to OS.
453  void dump(raw_ostream &OS) const;
454  };
455 
456  /// establishNestingLevels - Examines the loop nesting of the Src and Dst
457  /// instructions and establishes their shared loops. Sets the variables
458  /// CommonLevels, SrcLevels, and MaxLevels.
459  /// The source and destination instructions needn't be contained in the same
460  /// loop. The routine establishNestingLevels finds the level of most deeply
461  /// nested loop that contains them both, CommonLevels. An instruction that's
462  /// not contained in a loop is at level = 0. MaxLevels is equal to the level
463  /// of the source plus the level of the destination, minus CommonLevels.
464  /// This lets us allocate vectors MaxLevels in length, with room for every
465  /// distinct loop referenced in both the source and destination subscripts.
466  /// The variable SrcLevels is the nesting depth of the source instruction.
467  /// It's used to help calculate distinct loops referenced by the destination.
468  /// Here's the map from loops to levels:
469  /// 0 - unused
470  /// 1 - outermost common loop
471  /// ... - other common loops
472  /// CommonLevels - innermost common loop
473  /// ... - loops containing Src but not Dst
474  /// SrcLevels - innermost loop containing Src but not Dst
475  /// ... - loops containing Dst but not Src
476  /// MaxLevels - innermost loop containing Dst but not Src
477  /// Consider the follow code fragment:
478  /// for (a = ...) {
479  /// for (b = ...) {
480  /// for (c = ...) {
481  /// for (d = ...) {
482  /// A[] = ...;
483  /// }
484  /// }
485  /// for (e = ...) {
486  /// for (f = ...) {
487  /// for (g = ...) {
488  /// ... = A[];
489  /// }
490  /// }
491  /// }
492  /// }
493  /// }
494  /// If we're looking at the possibility of a dependence between the store
495  /// to A (the Src) and the load from A (the Dst), we'll note that they
496  /// have 2 loops in common, so CommonLevels will equal 2 and the direction
497  /// vector for Result will have 2 entries. SrcLevels = 4 and MaxLevels = 7.
498  /// A map from loop names to level indices would look like
499  /// a - 1
500  /// b - 2 = CommonLevels
501  /// c - 3
502  /// d - 4 = SrcLevels
503  /// e - 5
504  /// f - 6
505  /// g - 7 = MaxLevels
506  void establishNestingLevels(const Instruction *Src,
507  const Instruction *Dst);
508 
509  unsigned CommonLevels, SrcLevels, MaxLevels;
510 
511  /// mapSrcLoop - Given one of the loops containing the source, return
512  /// its level index in our numbering scheme.
513  unsigned mapSrcLoop(const Loop *SrcLoop) const;
514 
515  /// mapDstLoop - Given one of the loops containing the destination,
516  /// return its level index in our numbering scheme.
517  unsigned mapDstLoop(const Loop *DstLoop) const;
518 
519  /// isLoopInvariant - Returns true if Expression is loop invariant
520  /// in LoopNest.
521  bool isLoopInvariant(const SCEV *Expression, const Loop *LoopNest) const;
522 
523  /// Makes sure all subscript pairs share the same integer type by
524  /// sign-extending as necessary.
525  /// Sign-extending a subscript is safe because getelementptr assumes the
526  /// array subscripts are signed.
527  void unifySubscriptType(ArrayRef<Subscript *> Pairs);
528 
529  /// removeMatchingExtensions - Examines a subscript pair.
530  /// If the source and destination are identically sign (or zero)
531  /// extended, it strips off the extension in an effort to
532  /// simplify the actual analysis.
533  void removeMatchingExtensions(Subscript *Pair);
534 
535  /// collectCommonLoops - Finds the set of loops from the LoopNest that
536  /// have a level <= CommonLevels and are referred to by the SCEV Expression.
537  void collectCommonLoops(const SCEV *Expression,
538  const Loop *LoopNest,
539  SmallBitVector &Loops) const;
540 
541  /// checkSrcSubscript - Examines the SCEV Src, returning true iff it's
542  /// linear. Collect the set of loops mentioned by Src.
543  bool checkSrcSubscript(const SCEV *Src,
544  const Loop *LoopNest,
545  SmallBitVector &Loops);
546 
547  /// checkDstSubscript - Examines the SCEV Dst, returning true iff it's
548  /// linear. Collect the set of loops mentioned by Dst.
549  bool checkDstSubscript(const SCEV *Dst,
550  const Loop *LoopNest,
551  SmallBitVector &Loops);
552 
553  /// isKnownPredicate - Compare X and Y using the predicate Pred.
554  /// Basically a wrapper for SCEV::isKnownPredicate,
555  /// but tries harder, especially in the presence of sign and zero
556  /// extensions and symbolics.
557  bool isKnownPredicate(ICmpInst::Predicate Pred,
558  const SCEV *X,
559  const SCEV *Y) const;
560 
561  /// isKnownLessThan - Compare to see if S is less than Size
562  /// Another wrapper for isKnownNegative(S - max(Size, 1)) with some extra
563  /// checking if S is an AddRec and we can prove lessthan using the loop
564  /// bounds.
565  bool isKnownLessThan(const SCEV *S, const SCEV *Size) const;
566 
567  /// isKnownNonNegative - Compare to see if S is known not to be negative
568  /// Uses the fact that S comes from Ptr, which may be an inbound GEP,
569  /// Proving there is no wrapping going on.
570  bool isKnownNonNegative(const SCEV *S, const Value *Ptr) const;
571 
572  /// collectUpperBound - All subscripts are the same type (on my machine,
573  /// an i64). The loop bound may be a smaller type. collectUpperBound
574  /// find the bound, if available, and zero extends it to the Type T.
575  /// (I zero extend since the bound should always be >= 0.)
576  /// If no upper bound is available, return NULL.
577  const SCEV *collectUpperBound(const Loop *l, Type *T) const;
578 
579  /// collectConstantUpperBound - Calls collectUpperBound(), then
580  /// attempts to cast it to SCEVConstant. If the cast fails,
581  /// returns NULL.
582  const SCEVConstant *collectConstantUpperBound(const Loop *l, Type *T) const;
583 
584  /// classifyPair - Examines the subscript pair (the Src and Dst SCEVs)
585  /// and classifies it as either ZIV, SIV, RDIV, MIV, or Nonlinear.
586  /// Collects the associated loops in a set.
587  Subscript::ClassificationKind classifyPair(const SCEV *Src,
588  const Loop *SrcLoopNest,
589  const SCEV *Dst,
590  const Loop *DstLoopNest,
591  SmallBitVector &Loops);
592 
593  /// testZIV - Tests the ZIV subscript pair (Src and Dst) for dependence.
594  /// Returns true if any possible dependence is disproved.
595  /// If there might be a dependence, returns false.
596  /// If the dependence isn't proven to exist,
597  /// marks the Result as inconsistent.
598  bool testZIV(const SCEV *Src,
599  const SCEV *Dst,
600  FullDependence &Result) const;
601 
602  /// testSIV - Tests the SIV subscript pair (Src and Dst) for dependence.
603  /// Things of the form [c1 + a1*i] and [c2 + a2*j], where
604  /// i and j are induction variables, c1 and c2 are loop invariant,
605  /// and a1 and a2 are constant.
606  /// Returns true if any possible dependence is disproved.
607  /// If there might be a dependence, returns false.
608  /// Sets appropriate direction vector entry and, when possible,
609  /// the distance vector entry.
610  /// If the dependence isn't proven to exist,
611  /// marks the Result as inconsistent.
612  bool testSIV(const SCEV *Src,
613  const SCEV *Dst,
614  unsigned &Level,
615  FullDependence &Result,
616  Constraint &NewConstraint,
617  const SCEV *&SplitIter) const;
618 
619  /// testRDIV - Tests the RDIV subscript pair (Src and Dst) for dependence.
620  /// Things of the form [c1 + a1*i] and [c2 + a2*j]
621  /// where i and j are induction variables, c1 and c2 are loop invariant,
622  /// and a1 and a2 are constant.
623  /// With minor algebra, this test can also be used for things like
624  /// [c1 + a1*i + a2*j][c2].
625  /// Returns true if any possible dependence is disproved.
626  /// If there might be a dependence, returns false.
627  /// Marks the Result as inconsistent.
628  bool testRDIV(const SCEV *Src,
629  const SCEV *Dst,
630  FullDependence &Result) const;
631 
632  /// testMIV - Tests the MIV subscript pair (Src and Dst) for dependence.
633  /// Returns true if dependence disproved.
634  /// Can sometimes refine direction vectors.
635  bool testMIV(const SCEV *Src,
636  const SCEV *Dst,
637  const SmallBitVector &Loops,
638  FullDependence &Result) const;
639 
640  /// strongSIVtest - Tests the strong SIV subscript pair (Src and Dst)
641  /// for dependence.
642  /// Things of the form [c1 + a*i] and [c2 + a*i],
643  /// where i is an induction variable, c1 and c2 are loop invariant,
644  /// and a is a constant
645  /// Returns true if any possible dependence is disproved.
646  /// If there might be a dependence, returns false.
647  /// Sets appropriate direction and distance.
648  bool strongSIVtest(const SCEV *Coeff,
649  const SCEV *SrcConst,
650  const SCEV *DstConst,
651  const Loop *CurrentLoop,
652  unsigned Level,
653  FullDependence &Result,
654  Constraint &NewConstraint) const;
655 
656  /// weakCrossingSIVtest - Tests the weak-crossing SIV subscript pair
657  /// (Src and Dst) for dependence.
658  /// Things of the form [c1 + a*i] and [c2 - a*i],
659  /// where i is an induction variable, c1 and c2 are loop invariant,
660  /// and a is a constant.
661  /// Returns true if any possible dependence is disproved.
662  /// If there might be a dependence, returns false.
663  /// Sets appropriate direction entry.
664  /// Set consistent to false.
665  /// Marks the dependence as splitable.
666  bool weakCrossingSIVtest(const SCEV *SrcCoeff,
667  const SCEV *SrcConst,
668  const SCEV *DstConst,
669  const Loop *CurrentLoop,
670  unsigned Level,
671  FullDependence &Result,
672  Constraint &NewConstraint,
673  const SCEV *&SplitIter) const;
674 
675  /// ExactSIVtest - Tests the SIV subscript pair
676  /// (Src and Dst) for dependence.
677  /// Things of the form [c1 + a1*i] and [c2 + a2*i],
678  /// where i is an induction variable, c1 and c2 are loop invariant,
679  /// and a1 and a2 are constant.
680  /// Returns true if any possible dependence is disproved.
681  /// If there might be a dependence, returns false.
682  /// Sets appropriate direction entry.
683  /// Set consistent to false.
684  bool exactSIVtest(const SCEV *SrcCoeff,
685  const SCEV *DstCoeff,
686  const SCEV *SrcConst,
687  const SCEV *DstConst,
688  const Loop *CurrentLoop,
689  unsigned Level,
690  FullDependence &Result,
691  Constraint &NewConstraint) const;
692 
693  /// weakZeroSrcSIVtest - Tests the weak-zero SIV subscript pair
694  /// (Src and Dst) for dependence.
695  /// Things of the form [c1] and [c2 + a*i],
696  /// where i is an induction variable, c1 and c2 are loop invariant,
697  /// and a is a constant. See also weakZeroDstSIVtest.
698  /// Returns true if any possible dependence is disproved.
699  /// If there might be a dependence, returns false.
700  /// Sets appropriate direction entry.
701  /// Set consistent to false.
702  /// If loop peeling will break the dependence, mark appropriately.
703  bool weakZeroSrcSIVtest(const SCEV *DstCoeff,
704  const SCEV *SrcConst,
705  const SCEV *DstConst,
706  const Loop *CurrentLoop,
707  unsigned Level,
708  FullDependence &Result,
709  Constraint &NewConstraint) const;
710 
711  /// weakZeroDstSIVtest - Tests the weak-zero SIV subscript pair
712  /// (Src and Dst) for dependence.
713  /// Things of the form [c1 + a*i] and [c2],
714  /// where i is an induction variable, c1 and c2 are loop invariant,
715  /// and a is a constant. See also weakZeroSrcSIVtest.
716  /// Returns true if any possible dependence is disproved.
717  /// If there might be a dependence, returns false.
718  /// Sets appropriate direction entry.
719  /// Set consistent to false.
720  /// If loop peeling will break the dependence, mark appropriately.
721  bool weakZeroDstSIVtest(const SCEV *SrcCoeff,
722  const SCEV *SrcConst,
723  const SCEV *DstConst,
724  const Loop *CurrentLoop,
725  unsigned Level,
726  FullDependence &Result,
727  Constraint &NewConstraint) const;
728 
729  /// exactRDIVtest - Tests the RDIV subscript pair for dependence.
730  /// Things of the form [c1 + a*i] and [c2 + b*j],
731  /// where i and j are induction variable, c1 and c2 are loop invariant,
732  /// and a and b are constants.
733  /// Returns true if any possible dependence is disproved.
734  /// Marks the result as inconsistent.
735  /// Works in some cases that symbolicRDIVtest doesn't,
736  /// and vice versa.
737  bool exactRDIVtest(const SCEV *SrcCoeff,
738  const SCEV *DstCoeff,
739  const SCEV *SrcConst,
740  const SCEV *DstConst,
741  const Loop *SrcLoop,
742  const Loop *DstLoop,
743  FullDependence &Result) const;
744 
745  /// symbolicRDIVtest - Tests the RDIV subscript pair for dependence.
746  /// Things of the form [c1 + a*i] and [c2 + b*j],
747  /// where i and j are induction variable, c1 and c2 are loop invariant,
748  /// and a and b are constants.
749  /// Returns true if any possible dependence is disproved.
750  /// Marks the result as inconsistent.
751  /// Works in some cases that exactRDIVtest doesn't,
752  /// and vice versa. Can also be used as a backup for
753  /// ordinary SIV tests.
754  bool symbolicRDIVtest(const SCEV *SrcCoeff,
755  const SCEV *DstCoeff,
756  const SCEV *SrcConst,
757  const SCEV *DstConst,
758  const Loop *SrcLoop,
759  const Loop *DstLoop) const;
760 
761  /// gcdMIVtest - Tests an MIV subscript pair for dependence.
762  /// Returns true if any possible dependence is disproved.
763  /// Marks the result as inconsistent.
764  /// Can sometimes disprove the equal direction for 1 or more loops.
765  // Can handle some symbolics that even the SIV tests don't get,
766  /// so we use it as a backup for everything.
767  bool gcdMIVtest(const SCEV *Src,
768  const SCEV *Dst,
769  FullDependence &Result) const;
770 
771  /// banerjeeMIVtest - Tests an MIV subscript pair for dependence.
772  /// Returns true if any possible dependence is disproved.
773  /// Marks the result as inconsistent.
774  /// Computes directions.
775  bool banerjeeMIVtest(const SCEV *Src,
776  const SCEV *Dst,
777  const SmallBitVector &Loops,
778  FullDependence &Result) const;
779 
780  /// collectCoefficientInfo - Walks through the subscript,
781  /// collecting each coefficient, the associated loop bounds,
782  /// and recording its positive and negative parts for later use.
783  CoefficientInfo *collectCoeffInfo(const SCEV *Subscript,
784  bool SrcFlag,
785  const SCEV *&Constant) const;
786 
787  /// getPositivePart - X^+ = max(X, 0).
788  ///
789  const SCEV *getPositivePart(const SCEV *X) const;
790 
791  /// getNegativePart - X^- = min(X, 0).
792  ///
793  const SCEV *getNegativePart(const SCEV *X) const;
794 
795  /// getLowerBound - Looks through all the bounds info and
796  /// computes the lower bound given the current direction settings
797  /// at each level.
798  const SCEV *getLowerBound(BoundInfo *Bound) const;
799 
800  /// getUpperBound - Looks through all the bounds info and
801  /// computes the upper bound given the current direction settings
802  /// at each level.
803  const SCEV *getUpperBound(BoundInfo *Bound) const;
804 
805  /// exploreDirections - Hierarchically expands the direction vector
806  /// search space, combining the directions of discovered dependences
807  /// in the DirSet field of Bound. Returns the number of distinct
808  /// dependences discovered. If the dependence is disproved,
809  /// it will return 0.
810  unsigned exploreDirections(unsigned Level,
811  CoefficientInfo *A,
812  CoefficientInfo *B,
813  BoundInfo *Bound,
814  const SmallBitVector &Loops,
815  unsigned &DepthExpanded,
816  const SCEV *Delta) const;
817 
818  /// testBounds - Returns true iff the current bounds are plausible.
819  bool testBounds(unsigned char DirKind,
820  unsigned Level,
821  BoundInfo *Bound,
822  const SCEV *Delta) const;
823 
824  /// findBoundsALL - Computes the upper and lower bounds for level K
825  /// using the * direction. Records them in Bound.
826  void findBoundsALL(CoefficientInfo *A,
827  CoefficientInfo *B,
828  BoundInfo *Bound,
829  unsigned K) const;
830 
831  /// findBoundsLT - Computes the upper and lower bounds for level K
832  /// using the < direction. Records them in Bound.
833  void findBoundsLT(CoefficientInfo *A,
834  CoefficientInfo *B,
835  BoundInfo *Bound,
836  unsigned K) const;
837 
838  /// findBoundsGT - Computes the upper and lower bounds for level K
839  /// using the > direction. Records them in Bound.
840  void findBoundsGT(CoefficientInfo *A,
841  CoefficientInfo *B,
842  BoundInfo *Bound,
843  unsigned K) const;
844 
845  /// findBoundsEQ - Computes the upper and lower bounds for level K
846  /// using the = direction. Records them in Bound.
847  void findBoundsEQ(CoefficientInfo *A,
848  CoefficientInfo *B,
849  BoundInfo *Bound,
850  unsigned K) const;
851 
852  /// intersectConstraints - Updates X with the intersection
853  /// of the Constraints X and Y. Returns true if X has changed.
854  bool intersectConstraints(Constraint *X,
855  const Constraint *Y);
856 
857  /// propagate - Review the constraints, looking for opportunities
858  /// to simplify a subscript pair (Src and Dst).
859  /// Return true if some simplification occurs.
860  /// If the simplification isn't exact (that is, if it is conservative
861  /// in terms of dependence), set consistent to false.
862  bool propagate(const SCEV *&Src,
863  const SCEV *&Dst,
864  SmallBitVector &Loops,
865  SmallVectorImpl<Constraint> &Constraints,
866  bool &Consistent);
867 
868  /// propagateDistance - Attempt to propagate a distance
869  /// constraint into a subscript pair (Src and Dst).
870  /// Return true if some simplification occurs.
871  /// If the simplification isn't exact (that is, if it is conservative
872  /// in terms of dependence), set consistent to false.
873  bool propagateDistance(const SCEV *&Src,
874  const SCEV *&Dst,
875  Constraint &CurConstraint,
876  bool &Consistent);
877 
878  /// propagatePoint - Attempt to propagate a point
879  /// constraint into a subscript pair (Src and Dst).
880  /// Return true if some simplification occurs.
881  bool propagatePoint(const SCEV *&Src,
882  const SCEV *&Dst,
883  Constraint &CurConstraint);
884 
885  /// propagateLine - Attempt to propagate a line
886  /// constraint into a subscript pair (Src and Dst).
887  /// Return true if some simplification occurs.
888  /// If the simplification isn't exact (that is, if it is conservative
889  /// in terms of dependence), set consistent to false.
890  bool propagateLine(const SCEV *&Src,
891  const SCEV *&Dst,
892  Constraint &CurConstraint,
893  bool &Consistent);
894 
895  /// findCoefficient - Given a linear SCEV,
896  /// return the coefficient corresponding to specified loop.
897  /// If there isn't one, return the SCEV constant 0.
898  /// For example, given a*i + b*j + c*k, returning the coefficient
899  /// corresponding to the j loop would yield b.
900  const SCEV *findCoefficient(const SCEV *Expr,
901  const Loop *TargetLoop) const;
902 
903  /// zeroCoefficient - Given a linear SCEV,
904  /// return the SCEV given by zeroing out the coefficient
905  /// corresponding to the specified loop.
906  /// For example, given a*i + b*j + c*k, zeroing the coefficient
907  /// corresponding to the j loop would yield a*i + c*k.
908  const SCEV *zeroCoefficient(const SCEV *Expr,
909  const Loop *TargetLoop) const;
910 
911  /// addToCoefficient - Given a linear SCEV Expr,
912  /// return the SCEV given by adding some Value to the
913  /// coefficient corresponding to the specified TargetLoop.
914  /// For example, given a*i + b*j + c*k, adding 1 to the coefficient
915  /// corresponding to the j loop would yield a*i + (b+1)*j + c*k.
916  const SCEV *addToCoefficient(const SCEV *Expr,
917  const Loop *TargetLoop,
918  const SCEV *Value) const;
919 
920  /// updateDirection - Update direction vector entry
921  /// based on the current constraint.
922  void updateDirection(Dependence::DVEntry &Level,
923  const Constraint &CurConstraint) const;
924 
925  /// Given a linear access function, tries to recover subscripts
926  /// for each dimension of the array element access.
927  bool tryDelinearize(Instruction *Src, Instruction *Dst,
928  SmallVectorImpl<Subscript> &Pair);
929 
930  /// Tries to delinearize \p Src and \p Dst access functions for a fixed size
931  /// multi-dimensional array. Calls tryDelinearizeFixedSizeImpl() to
932  /// delinearize \p Src and \p Dst separately,
933  bool tryDelinearizeFixedSize(Instruction *Src, Instruction *Dst,
934  const SCEV *SrcAccessFn,
935  const SCEV *DstAccessFn,
936  SmallVectorImpl<const SCEV *> &SrcSubscripts,
937  SmallVectorImpl<const SCEV *> &DstSubscripts);
938 
939  /// Tries to delinearize access function for a multi-dimensional array with
940  /// symbolic runtime sizes.
941  /// Returns true upon success and false otherwise.
942  bool tryDelinearizeParametricSize(
943  Instruction *Src, Instruction *Dst, const SCEV *SrcAccessFn,
944  const SCEV *DstAccessFn, SmallVectorImpl<const SCEV *> &SrcSubscripts,
945  SmallVectorImpl<const SCEV *> &DstSubscripts);
946 
947  /// checkSubscript - Helper function for checkSrcSubscript and
948  /// checkDstSubscript to avoid duplicate code
949  bool checkSubscript(const SCEV *Expr, const Loop *LoopNest,
950  SmallBitVector &Loops, bool IsSrc);
951  }; // class DependenceInfo
952 
953  /// AnalysisPass to compute dependence information in a function
954  class DependenceAnalysis : public AnalysisInfoMixin<DependenceAnalysis> {
955  public:
958 
959  private:
960  static AnalysisKey Key;
962  }; // class DependenceAnalysis
963 
964  /// Printer pass to dump DA results.
966  : public PassInfoMixin<DependenceAnalysisPrinterPass> {
968 
970 
971  private:
972  raw_ostream &OS;
973  }; // class DependenceAnalysisPrinterPass
974 
975  /// Legacy pass manager pass to access dependence information
977  public:
978  static char ID; // Class identification, replacement for typeinfo
980 
981  bool runOnFunction(Function &F) override;
982  void releaseMemory() override;
983  void getAnalysisUsage(AnalysisUsage &) const override;
984  void print(raw_ostream &, const Module * = nullptr) const override;
985  DependenceInfo &getDI() const;
986 
987  private:
988  std::unique_ptr<DependenceInfo> info;
989  }; // class DependenceAnalysisWrapperPass
990 
991  /// createDependenceAnalysisPass - This creates an instance of the
992  /// DependenceAnalysis wrapper pass.
994 
995 } // namespace llvm
996 
997 #endif
llvm::PreservedAnalyses
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:152
llvm::Dependence::isSplitable
virtual bool isSplitable(unsigned Level) const
isSplitable - Returns true if splitting this loop will break the dependence.
Definition: DependenceAnalysis.h:171
llvm::FullDependence::isConfused
bool isConfused() const override
isConfused - Returns true if this dependence is confused (the compiler understands nothing and makes ...
Definition: DependenceAnalysis.h:224
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:17
llvm::Dependence::~Dependence
virtual ~Dependence()=default
llvm::Dependence::isFlow
bool isFlow() const
isFlow - Returns true if this is a flow (aka true) dependence.
Definition: DependenceAnalysis.cpp:235
llvm::HexPrintStyle::Upper
@ Upper
llvm::FullDependence::isConsistent
bool isConsistent() const override
isConsistent - Returns true if this dependence is consistent (occurs every time the source and destin...
Definition: DependenceAnalysis.h:228
llvm::DependenceAnalysisWrapperPass::getAnalysisUsage
void getAnalysisUsage(AnalysisUsage &) const override
getAnalysisUsage - This function should be overriden by passes that need analysis information to do t...
Definition: DependenceAnalysis.cpp:168
llvm::CmpInst::Predicate
Predicate
This enumeration lists the possible predicates for CmpInst subclasses.
Definition: InstrTypes.h:719
llvm::Dependence::DVEntry::LE
@ LE
Definition: DependenceAnalysis.h:88
llvm::PassInfoMixin
A CRTP mix-in to automatically provide informational APIs needed for passes.
Definition: PassManager.h:371
llvm::DependenceAnalysisWrapperPass
Legacy pass manager pass to access dependence information.
Definition: DependenceAnalysis.h:976
llvm::Function
Definition: Function.h:60
Pass.h
Loops
Hexagon Hardware Loops
Definition: HexagonHardwareLoops.cpp:372
llvm::Dependence::DVEntry::GE
@ GE
Definition: DependenceAnalysis.h:91
llvm::Dependence::getLevels
virtual unsigned getLevels() const
getLevels - Returns the number of common loops surrounding the source and destination of the dependen...
Definition: DependenceAnalysis.h:151
llvm::Dependence::dump
void dump(raw_ostream &OS) const
dump - For debugging purposes, dumps a dependence to OS.
Definition: DependenceAnalysis.cpp:593
llvm::FullDependence::isSplitable
bool isSplitable(unsigned Level) const override
isSplitable - Returns true if splitting the loop will break the dependence.
Definition: DependenceAnalysis.cpp:310
llvm::DependenceInfo::getFunction
Function * getFunction() const
Definition: DependenceAnalysis.h:331
llvm::DependenceInfo::DependenceInfo
DependenceInfo(Function *F, AAResults *AA, ScalarEvolution *SE, LoopInfo *LI)
Definition: DependenceAnalysis.h:271
llvm::ScalarEvolution
The main scalar evolution driver.
Definition: ScalarEvolution.h:449
llvm::Dependence
Dependence - This class represents a dependence between two memory memory references in a function.
Definition: DependenceAnalysis.h:71
FAM
FunctionAnalysisManager FAM
Definition: PassBuilderBindings.cpp:59
true
basic Basic Alias true
Definition: BasicAliasAnalysis.cpp:1886
llvm::Dependence::isUnordered
bool isUnordered() const
isUnordered - Returns true if dependence is Input
Definition: DependenceAnalysis.h:134
llvm::DependenceAnalysisWrapperPass::getDI
DependenceInfo & getDI() const
Definition: DependenceAnalysis.cpp:164
llvm::Dependence::isScalar
virtual bool isScalar(unsigned Level) const
isScalar - Returns true if a particular level is scalar; that is, if no subscript in the source or de...
Definition: DependenceAnalysis.cpp:250
llvm::Dependence::DVEntry::NONE
@ NONE
Definition: DependenceAnalysis.h:85
llvm::DependenceAnalysisWrapperPass::ID
static char ID
Definition: DependenceAnalysis.h:978
llvm::DependenceAnalysisWrapperPass::print
void print(raw_ostream &, const Module *=nullptr) const override
print - Print out the internal state of the pass.
Definition: DependenceAnalysis.cpp:207
llvm::dump
void dump(const SparseBitVector< ElementSize > &LHS, raw_ostream &out)
Definition: SparseBitVector.h:877
llvm::FullDependence::isPeelFirst
bool isPeelFirst(unsigned Level) const override
isPeelFirst - Returns true if peeling the first iteration from this loop will break this dependence.
Definition: DependenceAnalysis.cpp:295
llvm::FullDependence::isScalar
bool isScalar(unsigned Level) const override
isScalar - Returns true if a particular level is scalar; that is, if no subscript in the source or de...
Definition: DependenceAnalysis.cpp:287
llvm::Dependence::DVEntry::Distance
const SCEV * Distance
Definition: DependenceAnalysis.h:98
llvm::Dependence::isAnti
bool isAnti() const
isAnti - Returns true if this is an anti dependence.
Definition: DependenceAnalysis.cpp:241
llvm::Dependence::DVEntry::ALL
@ ALL
Definition: DependenceAnalysis.h:92
F
#define F(x, y, z)
Definition: MD5.cpp:55
llvm::Dependence::DVEntry
Dependence::DVEntry - Each level in the distance/direction vector has a direction (or perhaps a union...
Definition: DependenceAnalysis.h:84
llvm::Dependence::DVEntry::LT
@ LT
Definition: DependenceAnalysis.h:86
llvm::DependenceAnalysisWrapperPass::releaseMemory
void releaseMemory() override
releaseMemory() - This member can be implemented by a pass if it wants to be able to release its memo...
Definition: DependenceAnalysis.cpp:166
llvm::DependenceAnalysisWrapperPass::DependenceAnalysisWrapperPass
DependenceAnalysisWrapperPass()
Definition: DependenceAnalysis.cpp:147
llvm::AAResults
Definition: AliasAnalysis.h:511
llvm::FullDependence::FullDependence
FullDependence(Instruction *Src, Instruction *Dst, bool LoopIndependent, unsigned Levels)
Definition: DependenceAnalysis.cpp:258
llvm::Dependence::Dependence
Dependence(Instruction *Source, Instruction *Destination)
Definition: DependenceAnalysis.h:77
C
(vector float) vec_cmpeq(*A, *B) C
Definition: README_ALTIVEC.txt:86
llvm::ARM_PROC::A
@ A
Definition: ARMBaseInfo.h:34
Y
static GCMetadataPrinterRegistry::Add< OcamlGCMetadataPrinter > Y("ocaml", "ocaml 3.10-compatible collector")
llvm::createDependenceAnalysisWrapperPass
FunctionPass * createDependenceAnalysisWrapperPass()
createDependenceAnalysisPass - This creates an instance of the DependenceAnalysis wrapper pass.
Definition: DependenceAnalysis.cpp:152
llvm::AnalysisUsage
Represent the analysis usage information of a pass.
Definition: PassAnalysisSupport.h:47
l
This requires reassociating to forms of expressions that are already something that reassoc doesn t think about yet These two functions should generate the same code on big endian int * l
Definition: README.txt:100
false
Definition: StackSlotColoring.cpp:141
llvm::Dependence::DVEntry::GT
@ GT
Definition: DependenceAnalysis.h:89
B
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
llvm::Instruction
Definition: Instruction.h:42
llvm::Dependence::isConfused
virtual bool isConfused() const
isConfused - Returns true if this dependence is confused (the compiler understands nothing and makes ...
Definition: DependenceAnalysis.h:143
llvm::raw_ostream
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:54
llvm::Dependence::getDistance
virtual const SCEV * getDistance(unsigned Level) const
getDistance - Returns the distance (or NULL) associated with a particular level.
Definition: DependenceAnalysis.h:159
llvm::AnalysisManager::Invalidator
API to communicate dependencies between analyses during invalidation.
Definition: PassManager.h:667
llvm::DependenceInfo::invalidate
bool invalidate(Function &F, const PreservedAnalyses &PA, FunctionAnalysisManager::Invalidator &Inv)
Handle transitive invalidation when the cached analysis results go away.
Definition: DependenceAnalysis.cpp:3502
llvm::DependenceInfo::getSplitIteration
const SCEV * getSplitIteration(const Dependence &Dep, unsigned Level)
getSplitIteration - Give a dependence that's splittable at some particular level, return the iteratio...
Definition: DependenceAnalysis.cpp:3961
llvm::lltok::Kind
Kind
Definition: LLToken.h:18
X
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
llvm::Dependence::isOutput
bool isOutput() const
isOutput - Returns true if this is an output dependence.
Definition: DependenceAnalysis.cpp:229
llvm::DependenceAnalysisPrinterPass
Printer pass to dump DA results.
Definition: DependenceAnalysis.h:965
llvm::LegacyLegalizeActions::Lower
@ Lower
The operation itself must be expressed in terms of simpler actions on this target.
Definition: LegacyLegalizerInfo.h:58
llvm::SCEV
This class represents an analyzed expression in the program.
Definition: ScalarEvolution.h:75
llvm::DependenceInfo
DependenceInfo - This class is the main dependence-analysis driver.
Definition: DependenceAnalysis.h:269
llvm::Dependence::DVEntry::EQ
@ EQ
Definition: DependenceAnalysis.h:87
llvm::Dependence::DVEntry::Scalar
bool Scalar
Definition: DependenceAnalysis.h:94
D
static GCRegistry::Add< StatepointGC > D("statepoint-example", "an example strategy for statepoint")
llvm::AnalysisKey
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: PassManager.h:69
llvm::pdb::Empty
@ Empty
Definition: PDBTypes.h:395
llvm::Dependence::isPeelLast
virtual bool isPeelLast(unsigned Level) const
isPeelLast - Returns true if peeling the last iteration from this loop will break this dependence.
Definition: DependenceAnalysis.h:167
llvm::Dependence::isConsistent
virtual bool isConsistent() const
isConsistent - Returns true if this dependence is consistent (occurs every time the source and destin...
Definition: DependenceAnalysis.h:147
llvm::Dependence::operator=
Dependence & operator=(Dependence &&)=default
llvm::FullDependence::getDistance
const SCEV * getDistance(unsigned Level) const override
getDistance - Returns the distance (or NULL) associated with a particular level.
Definition: DependenceAnalysis.cpp:278
llvm::Module
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:65
llvm::Dependence::isPeelFirst
virtual bool isPeelFirst(unsigned Level) const
isPeelFirst - Returns true if peeling the first iteration from this loop will break this dependence.
Definition: DependenceAnalysis.h:163
llvm::AnalysisInfoMixin
A CRTP mix-in that provides informational APIs needed for analysis passes.
Definition: PassManager.h:394
llvm::Dependence::getDst
Instruction * getDst() const
getDst - Returns the destination instruction for this dependence.
Definition: DependenceAnalysis.h:110
llvm::Dependence::isInput
bool isInput() const
isInput - Returns true if this is an input dependence.
Definition: DependenceAnalysis.cpp:223
llvm::Sched::Source
@ Source
Definition: TargetLowering.h:99
llvm::LoopInfo
Definition: LoopInfo.h:1102
llvm::FullDependence::isPeelLast
bool isPeelLast(unsigned Level) const override
isPeelLast - Returns true if peeling the last iteration from this loop will break this dependence.
Definition: DependenceAnalysis.cpp:303
llvm::DependenceAnalysis
AnalysisPass to compute dependence information in a function.
Definition: DependenceAnalysis.h:954
S
add sub stmia L5 ldr r0 bl L_printf $stub Instead of a and a wouldn t it be better to do three moves *Return an aggregate type is even return S
Definition: README.txt:210
llvm::PICLevel::Level
Level
Definition: CodeGen.h:33
llvm::Dependence::DVEntry::Direction
unsigned char Direction
Definition: DependenceAnalysis.h:93
llvm::Dependence::setNextPredecessor
void setNextPredecessor(const Dependence *pred)
setNextPredecessor - Sets the value of the NextPredecessor field.
Definition: DependenceAnalysis.h:188
llvm::DependenceAnalysis::run
Result run(Function &F, FunctionAnalysisManager &FAM)
Definition: DependenceAnalysis.cpp:128
llvm::Dependence::DVEntry::NE
@ NE
Definition: DependenceAnalysis.h:90
llvm::Dependence::setNextSuccessor
void setNextSuccessor(const Dependence *succ)
setNextSuccessor - Sets the value of the NextSuccessor field.
Definition: DependenceAnalysis.h:192
llvm::Dependence::DVEntry::Splitable
bool Splitable
Definition: DependenceAnalysis.h:97
Direction
Loop::LoopBounds::Direction Direction
Definition: LoopInfo.cpp:226
llvm::TargetStackID::Value
Value
Definition: TargetFrameLowering.h:27
PassManager.h
AA
llvm::Dependence::Dependence
Dependence(Dependence &&)=default
llvm::DependenceInfo::depends
std::unique_ptr< Dependence > depends(Instruction *Src, Instruction *Dst, bool PossiblyLoopIndependent)
depends - Tests for a dependence between the Src and Dst instructions.
Definition: DependenceAnalysis.cpp:3527
llvm::Dependence::getDirection
virtual unsigned getDirection(unsigned Level) const
getDirection - Returns the direction associated with a particular level.
Definition: DependenceAnalysis.h:155
Instructions.h
llvm::Dependence::isOrdered
bool isOrdered() const
isOrdered - Returns true if dependence is Output, Flow, or Anti
Definition: DependenceAnalysis.h:130
SmallBitVector.h
llvm::Dependence::getNextPredecessor
const Dependence * getNextPredecessor() const
getNextPredecessor - Returns the value of the NextPredecessor field.
Definition: DependenceAnalysis.h:180
llvm::FullDependence::isLoopIndependent
bool isLoopIndependent() const override
isLoopIndependent - Returns true if this is a loop-independent dependence.
Definition: DependenceAnalysis.h:219
llvm::SystemZICMP::Any
@ Any
Definition: SystemZISelLowering.h:377
llvm::FullDependence::getDirection
unsigned getDirection(unsigned Level) const override
getDirection - Returns the direction associated with a particular level.
Definition: DependenceAnalysis.cpp:271
llvm::AnalysisManager
A container for analyses that lazily runs them and caches their results.
Definition: InstructionSimplify.h:42
pred
hexagon gen pred
Definition: HexagonGenPredicate.cpp:134
llvm::FunctionPass
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:308
llvm::Dependence::DVEntry::DVEntry
DVEntry()
Definition: DependenceAnalysis.h:99
llvm::FullDependence::getLevels
unsigned getLevels() const override
getLevels - Returns the number of common loops surrounding the source and destination of the dependen...
Definition: DependenceAnalysis.h:232
llvm::DependenceAnalysis::Result
DependenceInfo Result
Definition: DependenceAnalysis.h:956
llvm::Dependence::isLoopIndependent
virtual bool isLoopIndependent() const
isLoopIndependent - Returns true if this is a loop-independent dependence.
Definition: DependenceAnalysis.h:138
llvm::DependenceAnalysisPrinterPass::DependenceAnalysisPrinterPass
DependenceAnalysisPrinterPass(raw_ostream &OS)
Definition: DependenceAnalysis.h:967
llvm::Dependence::getNextSuccessor
const Dependence * getNextSuccessor() const
getNextSuccessor - Returns the value of the NextSuccessor field.
Definition: DependenceAnalysis.h:184
llvm::DependenceAnalysisPrinterPass::run
PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM)
Definition: DependenceAnalysis.cpp:213
llvm::Dependence::getSrc
Instruction * getSrc() const
getSrc - Returns the source instruction for this dependence.
Definition: DependenceAnalysis.h:106
llvm::FullDependence
FullDependence - This class represents a dependence between two memory references in a function.
Definition: DependenceAnalysis.h:212
llvm::DependenceAnalysisWrapperPass::runOnFunction
bool runOnFunction(Function &F) override
runOnFunction - Virtual method overriden by subclasses to do the per-function processing of the pass.
Definition: DependenceAnalysis.cpp:156
llvm::Dependence::DVEntry::PeelFirst
bool PeelFirst
Definition: DependenceAnalysis.h:95
llvm::Dependence::DVEntry::PeelLast
bool PeelLast
Definition: DependenceAnalysis.h:96