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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  Instruction *Destination) :
79  Src(Source),
80  Dst(Destination),
81  NextPredecessor(nullptr),
82  NextSuccessor(nullptr) {}
83  virtual ~Dependence() {}
84 
85  /// Dependence::DVEntry - Each level in the distance/direction vector
86  /// has a direction (or perhaps a union of several directions), and
87  /// perhaps a distance.
88  struct DVEntry {
89  enum { NONE = 0,
90  LT = 1,
91  EQ = 2,
92  LE = 3,
93  GT = 4,
94  NE = 5,
95  GE = 6,
96  ALL = 7 };
97  unsigned char Direction : 3; // Init to ALL, then refine.
98  bool Scalar : 1; // Init to true.
99  bool PeelFirst : 1; // Peeling the first iteration will break dependence.
100  bool PeelLast : 1; // Peeling the last iteration will break the dependence.
101  bool Splitable : 1; // Splitting the loop will break dependence.
102  const SCEV *Distance; // NULL implies no distance available.
104  PeelLast(false), Splitable(false), Distance(nullptr) { }
105  };
106 
107  /// getSrc - Returns the source instruction for this dependence.
108  ///
109  Instruction *getSrc() const { return Src; }
110 
111  /// getDst - Returns the destination instruction for this dependence.
112  ///
113  Instruction *getDst() const { return Dst; }
114 
115  /// isInput - Returns true if this is an input dependence.
116  ///
117  bool isInput() const;
118 
119  /// isOutput - Returns true if this is an output dependence.
120  ///
121  bool isOutput() const;
122 
123  /// isFlow - Returns true if this is a flow (aka true) dependence.
124  ///
125  bool isFlow() const;
126 
127  /// isAnti - Returns true if this is an anti dependence.
128  ///
129  bool isAnti() const;
130 
131  /// isOrdered - Returns true if dependence is Output, Flow, or Anti
132  ///
133  bool isOrdered() const { return isOutput() || isFlow() || isAnti(); }
134 
135  /// isUnordered - Returns true if dependence is Input
136  ///
137  bool isUnordered() const { return isInput(); }
138 
139  /// isLoopIndependent - Returns true if this is a loop-independent
140  /// dependence.
141  virtual bool isLoopIndependent() const { return true; }
142 
143  /// isConfused - Returns true if this dependence is confused
144  /// (the compiler understands nothing and makes worst-case
145  /// assumptions).
146  virtual bool isConfused() const { return true; }
147 
148  /// isConsistent - Returns true if this dependence is consistent
149  /// (occurs every time the source and destination are executed).
150  virtual bool isConsistent() const { return false; }
151 
152  /// getLevels - Returns the number of common loops surrounding the
153  /// source and destination of the dependence.
154  virtual unsigned getLevels() const { return 0; }
155 
156  /// getDirection - Returns the direction associated with a particular
157  /// level.
158  virtual unsigned getDirection(unsigned Level) const { return DVEntry::ALL; }
159 
160  /// getDistance - Returns the distance (or NULL) associated with a
161  /// particular level.
162  virtual const SCEV *getDistance(unsigned Level) const { return nullptr; }
163 
164  /// isPeelFirst - Returns true if peeling the first iteration from
165  /// this loop will break this dependence.
166  virtual bool isPeelFirst(unsigned Level) const { return false; }
167 
168  /// isPeelLast - Returns true if peeling the last iteration from
169  /// this loop will break this dependence.
170  virtual bool isPeelLast(unsigned Level) const { return false; }
171 
172  /// isSplitable - Returns true if splitting this loop will break
173  /// the dependence.
174  virtual bool isSplitable(unsigned Level) const { return false; }
175 
176  /// isScalar - Returns true if a particular level is scalar; that is,
177  /// if no subscript in the source or destination mention the induction
178  /// variable associated with the loop at this level.
179  virtual bool isScalar(unsigned Level) const;
180 
181  /// getNextPredecessor - Returns the value of the NextPredecessor
182  /// field.
183  const Dependence *getNextPredecessor() const { return NextPredecessor; }
184 
185  /// getNextSuccessor - Returns the value of the NextSuccessor
186  /// field.
187  const Dependence *getNextSuccessor() const { return NextSuccessor; }
188 
189  /// setNextPredecessor - Sets the value of the NextPredecessor
190  /// field.
191  void setNextPredecessor(const Dependence *pred) { NextPredecessor = pred; }
192 
193  /// setNextSuccessor - Sets the value of the NextSuccessor
194  /// field.
195  void setNextSuccessor(const Dependence *succ) { NextSuccessor = succ; }
196 
197  /// dump - For debugging purposes, dumps a dependence to OS.
198  ///
199  void dump(raw_ostream &OS) const;
200 
201  private:
202  Instruction *Src, *Dst;
203  const Dependence *NextPredecessor, *NextSuccessor;
204  friend class DependenceInfo;
205  };
206 
207  /// FullDependence - This class represents a dependence between two memory
208  /// references in a function. It contains detailed information about the
209  /// dependence (direction vectors, etc.) and is used when the compiler is
210  /// able to accurately analyze the interaction of the references; that is,
211  /// it is not a confused dependence (see Dependence). In most cases
212  /// (for output, flow, and anti dependences), the dependence implies an
213  /// ordering, where the source must precede the destination; in contrast,
214  /// input dependences are unordered.
215  class FullDependence final : public Dependence {
216  public:
217  FullDependence(Instruction *Src, Instruction *Dst, bool LoopIndependent,
218  unsigned Levels);
219 
220  /// isLoopIndependent - Returns true if this is a loop-independent
221  /// dependence.
222  bool isLoopIndependent() const override { return LoopIndependent; }
223 
224  /// isConfused - Returns true if this dependence is confused
225  /// (the compiler understands nothing and makes worst-case
226  /// assumptions).
227  bool isConfused() const override { return false; }
228 
229  /// isConsistent - Returns true if this dependence is consistent
230  /// (occurs every time the source and destination are executed).
231  bool isConsistent() const override { return Consistent; }
232 
233  /// getLevels - Returns the number of common loops surrounding the
234  /// source and destination of the dependence.
235  unsigned getLevels() const override { return Levels; }
236 
237  /// getDirection - Returns the direction associated with a particular
238  /// level.
239  unsigned getDirection(unsigned Level) const override;
240 
241  /// getDistance - Returns the distance (or NULL) associated with a
242  /// particular level.
243  const SCEV *getDistance(unsigned Level) const override;
244 
245  /// isPeelFirst - Returns true if peeling the first iteration from
246  /// this loop will break this dependence.
247  bool isPeelFirst(unsigned Level) const override;
248 
249  /// isPeelLast - Returns true if peeling the last iteration from
250  /// this loop will break this dependence.
251  bool isPeelLast(unsigned Level) const override;
252 
253  /// isSplitable - Returns true if splitting the loop will break
254  /// the dependence.
255  bool isSplitable(unsigned Level) const override;
256 
257  /// isScalar - Returns true if a particular level is scalar; that is,
258  /// if no subscript in the source or destination mention the induction
259  /// variable associated with the loop at this level.
260  bool isScalar(unsigned Level) const override;
261 
262  private:
263  unsigned short Levels;
264  bool LoopIndependent;
265  bool Consistent; // Init to true, then refine.
266  std::unique_ptr<DVEntry[]> DV;
267  friend class DependenceInfo;
268  };
269 
270  /// DependenceInfo - This class is the main dependence-analysis driver.
271  ///
273  public:
275  LoopInfo *LI)
276  : AA(AA), SE(SE), LI(LI), F(F) {}
277 
278  /// Handle transitive invalidation when the cached analysis results go away.
279  bool invalidate(Function &F, const PreservedAnalyses &PA,
281 
282  /// depends - Tests for a dependence between the Src and Dst instructions.
283  /// Returns NULL if no dependence; otherwise, returns a Dependence (or a
284  /// FullDependence) with as much information as can be gleaned.
285  /// The flag PossiblyLoopIndependent should be set by the caller
286  /// if it appears that control flow can reach from Src to Dst
287  /// without traversing a loop back edge.
288  std::unique_ptr<Dependence> depends(Instruction *Src,
289  Instruction *Dst,
290  bool PossiblyLoopIndependent);
291 
292  /// getSplitIteration - Give a dependence that's splittable at some
293  /// particular level, return the iteration that should be used to split
294  /// the loop.
295  ///
296  /// Generally, the dependence analyzer will be used to build
297  /// a dependence graph for a function (basically a map from instructions
298  /// to dependences). Looking for cycles in the graph shows us loops
299  /// that cannot be trivially vectorized/parallelized.
300  ///
301  /// We can try to improve the situation by examining all the dependences
302  /// that make up the cycle, looking for ones we can break.
303  /// Sometimes, peeling the first or last iteration of a loop will break
304  /// dependences, and there are flags for those possibilities.
305  /// Sometimes, splitting a loop at some other iteration will do the trick,
306  /// and we've got a flag for that case. Rather than waste the space to
307  /// record the exact iteration (since we rarely know), we provide
308  /// a method that calculates the iteration. It's a drag that it must work
309  /// from scratch, but wonderful in that it's possible.
310  ///
311  /// Here's an example:
312  ///
313  /// for (i = 0; i < 10; i++)
314  /// A[i] = ...
315  /// ... = A[11 - i]
316  ///
317  /// There's a loop-carried flow dependence from the store to the load,
318  /// found by the weak-crossing SIV test. The dependence will have a flag,
319  /// indicating that the dependence can be broken by splitting the loop.
320  /// Calling getSplitIteration will return 5.
321  /// Splitting the loop breaks the dependence, like so:
322  ///
323  /// for (i = 0; i <= 5; i++)
324  /// A[i] = ...
325  /// ... = A[11 - i]
326  /// for (i = 6; i < 10; i++)
327  /// A[i] = ...
328  /// ... = A[11 - i]
329  ///
330  /// breaks the dependence and allows us to vectorize/parallelize
331  /// both loops.
332  const SCEV *getSplitIteration(const Dependence &Dep, unsigned Level);
333 
334  Function *getFunction() const { return F; }
335 
336  private:
337  AAResults *AA;
338  ScalarEvolution *SE;
339  LoopInfo *LI;
340  Function *F;
341 
342  /// Subscript - This private struct represents a pair of subscripts from
343  /// a pair of potentially multi-dimensional array references. We use a
344  /// vector of them to guide subscript partitioning.
345  struct Subscript {
346  const SCEV *Src;
347  const SCEV *Dst;
348  enum ClassificationKind { ZIV, SIV, RDIV, MIV, NonLinear } Classification;
349  SmallBitVector Loops;
350  SmallBitVector GroupLoops;
351  SmallBitVector Group;
352  };
353 
354  struct CoefficientInfo {
355  const SCEV *Coeff;
356  const SCEV *PosPart;
357  const SCEV *NegPart;
358  const SCEV *Iterations;
359  };
360 
361  struct BoundInfo {
362  const SCEV *Iterations;
363  const SCEV *Upper[8];
364  const SCEV *Lower[8];
365  unsigned char Direction;
366  unsigned char DirSet;
367  };
368 
369  /// Constraint - This private class represents a constraint, as defined
370  /// in the paper
371  ///
372  /// Practical Dependence Testing
373  /// Goff, Kennedy, Tseng
374  /// PLDI 1991
375  ///
376  /// There are 5 kinds of constraint, in a hierarchy.
377  /// 1) Any - indicates no constraint, any dependence is possible.
378  /// 2) Line - A line ax + by = c, where a, b, and c are parameters,
379  /// representing the dependence equation.
380  /// 3) Distance - The value d of the dependence distance;
381  /// 4) Point - A point <x, y> representing the dependence from
382  /// iteration x to iteration y.
383  /// 5) Empty - No dependence is possible.
384  class Constraint {
385  private:
386  enum ConstraintKind { Empty, Point, Distance, Line, Any } Kind;
387  ScalarEvolution *SE;
388  const SCEV *A;
389  const SCEV *B;
390  const SCEV *C;
391  const Loop *AssociatedLoop;
392 
393  public:
394  /// isEmpty - Return true if the constraint is of kind Empty.
395  bool isEmpty() const { return Kind == Empty; }
396 
397  /// isPoint - Return true if the constraint is of kind Point.
398  bool isPoint() const { return Kind == Point; }
399 
400  /// isDistance - Return true if the constraint is of kind Distance.
401  bool isDistance() const { return Kind == Distance; }
402 
403  /// isLine - Return true if the constraint is of kind Line.
404  /// Since Distance's can also be represented as Lines, we also return
405  /// true if the constraint is of kind Distance.
406  bool isLine() const { return Kind == Line || Kind == Distance; }
407 
408  /// isAny - Return true if the constraint is of kind Any;
409  bool isAny() const { return Kind == Any; }
410 
411  /// getX - If constraint is a point <X, Y>, returns X.
412  /// Otherwise assert.
413  const SCEV *getX() const;
414 
415  /// getY - If constraint is a point <X, Y>, returns Y.
416  /// Otherwise assert.
417  const SCEV *getY() const;
418 
419  /// getA - If constraint is a line AX + BY = C, returns A.
420  /// Otherwise assert.
421  const SCEV *getA() const;
422 
423  /// getB - If constraint is a line AX + BY = C, returns B.
424  /// Otherwise assert.
425  const SCEV *getB() const;
426 
427  /// getC - If constraint is a line AX + BY = C, returns C.
428  /// Otherwise assert.
429  const SCEV *getC() const;
430 
431  /// getD - If constraint is a distance, returns D.
432  /// Otherwise assert.
433  const SCEV *getD() const;
434 
435  /// getAssociatedLoop - Returns the loop associated with this constraint.
436  const Loop *getAssociatedLoop() const;
437 
438  /// setPoint - Change a constraint to Point.
439  void setPoint(const SCEV *X, const SCEV *Y, const Loop *CurrentLoop);
440 
441  /// setLine - Change a constraint to Line.
442  void setLine(const SCEV *A, const SCEV *B,
443  const SCEV *C, const Loop *CurrentLoop);
444 
445  /// setDistance - Change a constraint to Distance.
446  void setDistance(const SCEV *D, const Loop *CurrentLoop);
447 
448  /// setEmpty - Change a constraint to Empty.
449  void setEmpty();
450 
451  /// setAny - Change a constraint to Any.
452  void setAny(ScalarEvolution *SE);
453 
454  /// dump - For debugging purposes. Dumps the constraint
455  /// out to OS.
456  void dump(raw_ostream &OS) const;
457  };
458 
459  /// establishNestingLevels - Examines the loop nesting of the Src and Dst
460  /// instructions and establishes their shared loops. Sets the variables
461  /// CommonLevels, SrcLevels, and MaxLevels.
462  /// The source and destination instructions needn't be contained in the same
463  /// loop. The routine establishNestingLevels finds the level of most deeply
464  /// nested loop that contains them both, CommonLevels. An instruction that's
465  /// not contained in a loop is at level = 0. MaxLevels is equal to the level
466  /// of the source plus the level of the destination, minus CommonLevels.
467  /// This lets us allocate vectors MaxLevels in length, with room for every
468  /// distinct loop referenced in both the source and destination subscripts.
469  /// The variable SrcLevels is the nesting depth of the source instruction.
470  /// It's used to help calculate distinct loops referenced by the destination.
471  /// Here's the map from loops to levels:
472  /// 0 - unused
473  /// 1 - outermost common loop
474  /// ... - other common loops
475  /// CommonLevels - innermost common loop
476  /// ... - loops containing Src but not Dst
477  /// SrcLevels - innermost loop containing Src but not Dst
478  /// ... - loops containing Dst but not Src
479  /// MaxLevels - innermost loop containing Dst but not Src
480  /// Consider the follow code fragment:
481  /// for (a = ...) {
482  /// for (b = ...) {
483  /// for (c = ...) {
484  /// for (d = ...) {
485  /// A[] = ...;
486  /// }
487  /// }
488  /// for (e = ...) {
489  /// for (f = ...) {
490  /// for (g = ...) {
491  /// ... = A[];
492  /// }
493  /// }
494  /// }
495  /// }
496  /// }
497  /// If we're looking at the possibility of a dependence between the store
498  /// to A (the Src) and the load from A (the Dst), we'll note that they
499  /// have 2 loops in common, so CommonLevels will equal 2 and the direction
500  /// vector for Result will have 2 entries. SrcLevels = 4 and MaxLevels = 7.
501  /// A map from loop names to level indices would look like
502  /// a - 1
503  /// b - 2 = CommonLevels
504  /// c - 3
505  /// d - 4 = SrcLevels
506  /// e - 5
507  /// f - 6
508  /// g - 7 = MaxLevels
509  void establishNestingLevels(const Instruction *Src,
510  const Instruction *Dst);
511 
512  unsigned CommonLevels, SrcLevels, MaxLevels;
513 
514  /// mapSrcLoop - Given one of the loops containing the source, return
515  /// its level index in our numbering scheme.
516  unsigned mapSrcLoop(const Loop *SrcLoop) const;
517 
518  /// mapDstLoop - Given one of the loops containing the destination,
519  /// return its level index in our numbering scheme.
520  unsigned mapDstLoop(const Loop *DstLoop) const;
521 
522  /// isLoopInvariant - Returns true if Expression is loop invariant
523  /// in LoopNest.
524  bool isLoopInvariant(const SCEV *Expression, const Loop *LoopNest) const;
525 
526  /// Makes sure all subscript pairs share the same integer type by
527  /// sign-extending as necessary.
528  /// Sign-extending a subscript is safe because getelementptr assumes the
529  /// array subscripts are signed.
530  void unifySubscriptType(ArrayRef<Subscript *> Pairs);
531 
532  /// removeMatchingExtensions - Examines a subscript pair.
533  /// If the source and destination are identically sign (or zero)
534  /// extended, it strips off the extension in an effort to
535  /// simplify the actual analysis.
536  void removeMatchingExtensions(Subscript *Pair);
537 
538  /// collectCommonLoops - Finds the set of loops from the LoopNest that
539  /// have a level <= CommonLevels and are referred to by the SCEV Expression.
540  void collectCommonLoops(const SCEV *Expression,
541  const Loop *LoopNest,
542  SmallBitVector &Loops) const;
543 
544  /// checkSrcSubscript - Examines the SCEV Src, returning true iff it's
545  /// linear. Collect the set of loops mentioned by Src.
546  bool checkSrcSubscript(const SCEV *Src,
547  const Loop *LoopNest,
548  SmallBitVector &Loops);
549 
550  /// checkDstSubscript - Examines the SCEV Dst, returning true iff it's
551  /// linear. Collect the set of loops mentioned by Dst.
552  bool checkDstSubscript(const SCEV *Dst,
553  const Loop *LoopNest,
554  SmallBitVector &Loops);
555 
556  /// isKnownPredicate - Compare X and Y using the predicate Pred.
557  /// Basically a wrapper for SCEV::isKnownPredicate,
558  /// but tries harder, especially in the presence of sign and zero
559  /// extensions and symbolics.
560  bool isKnownPredicate(ICmpInst::Predicate Pred,
561  const SCEV *X,
562  const SCEV *Y) const;
563 
564  /// isKnownLessThan - Compare to see if S is less than Size
565  /// Another wrapper for isKnownNegative(S - max(Size, 1)) with some extra
566  /// checking if S is an AddRec and we can prove lessthan using the loop
567  /// bounds.
568  bool isKnownLessThan(const SCEV *S, const SCEV *Size) const;
569 
570  /// isKnownNonNegative - Compare to see if S is known not to be negative
571  /// Uses the fact that S comes from Ptr, which may be an inbound GEP,
572  /// Proving there is no wrapping going on.
573  bool isKnownNonNegative(const SCEV *S, const Value *Ptr) const;
574 
575  /// collectUpperBound - All subscripts are the same type (on my machine,
576  /// an i64). The loop bound may be a smaller type. collectUpperBound
577  /// find the bound, if available, and zero extends it to the Type T.
578  /// (I zero extend since the bound should always be >= 0.)
579  /// If no upper bound is available, return NULL.
580  const SCEV *collectUpperBound(const Loop *l, Type *T) const;
581 
582  /// collectConstantUpperBound - Calls collectUpperBound(), then
583  /// attempts to cast it to SCEVConstant. If the cast fails,
584  /// returns NULL.
585  const SCEVConstant *collectConstantUpperBound(const Loop *l, Type *T) const;
586 
587  /// classifyPair - Examines the subscript pair (the Src and Dst SCEVs)
588  /// and classifies it as either ZIV, SIV, RDIV, MIV, or Nonlinear.
589  /// Collects the associated loops in a set.
590  Subscript::ClassificationKind classifyPair(const SCEV *Src,
591  const Loop *SrcLoopNest,
592  const SCEV *Dst,
593  const Loop *DstLoopNest,
594  SmallBitVector &Loops);
595 
596  /// testZIV - Tests the ZIV subscript pair (Src and Dst) for dependence.
597  /// Returns true if any possible dependence is disproved.
598  /// If there might be a dependence, returns false.
599  /// If the dependence isn't proven to exist,
600  /// marks the Result as inconsistent.
601  bool testZIV(const SCEV *Src,
602  const SCEV *Dst,
603  FullDependence &Result) const;
604 
605  /// testSIV - Tests the SIV subscript pair (Src and Dst) for dependence.
606  /// Things of the form [c1 + a1*i] and [c2 + a2*j], where
607  /// i and j are induction variables, c1 and c2 are loop invariant,
608  /// and a1 and a2 are constant.
609  /// Returns true if any possible dependence is disproved.
610  /// If there might be a dependence, returns false.
611  /// Sets appropriate direction vector entry and, when possible,
612  /// the distance vector entry.
613  /// If the dependence isn't proven to exist,
614  /// marks the Result as inconsistent.
615  bool testSIV(const SCEV *Src,
616  const SCEV *Dst,
617  unsigned &Level,
618  FullDependence &Result,
619  Constraint &NewConstraint,
620  const SCEV *&SplitIter) const;
621 
622  /// testRDIV - Tests the RDIV subscript pair (Src and Dst) for dependence.
623  /// Things of the form [c1 + a1*i] and [c2 + a2*j]
624  /// where i and j are induction variables, c1 and c2 are loop invariant,
625  /// and a1 and a2 are constant.
626  /// With minor algebra, this test can also be used for things like
627  /// [c1 + a1*i + a2*j][c2].
628  /// Returns true if any possible dependence is disproved.
629  /// If there might be a dependence, returns false.
630  /// Marks the Result as inconsistent.
631  bool testRDIV(const SCEV *Src,
632  const SCEV *Dst,
633  FullDependence &Result) const;
634 
635  /// testMIV - Tests the MIV subscript pair (Src and Dst) for dependence.
636  /// Returns true if dependence disproved.
637  /// Can sometimes refine direction vectors.
638  bool testMIV(const SCEV *Src,
639  const SCEV *Dst,
640  const SmallBitVector &Loops,
641  FullDependence &Result) const;
642 
643  /// strongSIVtest - Tests the strong SIV subscript pair (Src and Dst)
644  /// for dependence.
645  /// Things of the form [c1 + a*i] and [c2 + a*i],
646  /// where i is an induction variable, c1 and c2 are loop invariant,
647  /// and a is a constant
648  /// Returns true if any possible dependence is disproved.
649  /// If there might be a dependence, returns false.
650  /// Sets appropriate direction and distance.
651  bool strongSIVtest(const SCEV *Coeff,
652  const SCEV *SrcConst,
653  const SCEV *DstConst,
654  const Loop *CurrentLoop,
655  unsigned Level,
656  FullDependence &Result,
657  Constraint &NewConstraint) const;
658 
659  /// weakCrossingSIVtest - Tests the weak-crossing SIV subscript pair
660  /// (Src and Dst) for dependence.
661  /// Things of the form [c1 + a*i] and [c2 - a*i],
662  /// where i is an induction variable, c1 and c2 are loop invariant,
663  /// and a is a constant.
664  /// Returns true if any possible dependence is disproved.
665  /// If there might be a dependence, returns false.
666  /// Sets appropriate direction entry.
667  /// Set consistent to false.
668  /// Marks the dependence as splitable.
669  bool weakCrossingSIVtest(const SCEV *SrcCoeff,
670  const SCEV *SrcConst,
671  const SCEV *DstConst,
672  const Loop *CurrentLoop,
673  unsigned Level,
674  FullDependence &Result,
675  Constraint &NewConstraint,
676  const SCEV *&SplitIter) const;
677 
678  /// ExactSIVtest - Tests the SIV subscript pair
679  /// (Src and Dst) for dependence.
680  /// Things of the form [c1 + a1*i] and [c2 + a2*i],
681  /// where i is an induction variable, c1 and c2 are loop invariant,
682  /// and a1 and a2 are constant.
683  /// Returns true if any possible dependence is disproved.
684  /// If there might be a dependence, returns false.
685  /// Sets appropriate direction entry.
686  /// Set consistent to false.
687  bool exactSIVtest(const SCEV *SrcCoeff,
688  const SCEV *DstCoeff,
689  const SCEV *SrcConst,
690  const SCEV *DstConst,
691  const Loop *CurrentLoop,
692  unsigned Level,
693  FullDependence &Result,
694  Constraint &NewConstraint) const;
695 
696  /// weakZeroSrcSIVtest - Tests the weak-zero SIV subscript pair
697  /// (Src and Dst) for dependence.
698  /// Things of the form [c1] and [c2 + a*i],
699  /// where i is an induction variable, c1 and c2 are loop invariant,
700  /// and a is a constant. See also weakZeroDstSIVtest.
701  /// Returns true if any possible dependence is disproved.
702  /// If there might be a dependence, returns false.
703  /// Sets appropriate direction entry.
704  /// Set consistent to false.
705  /// If loop peeling will break the dependence, mark appropriately.
706  bool weakZeroSrcSIVtest(const SCEV *DstCoeff,
707  const SCEV *SrcConst,
708  const SCEV *DstConst,
709  const Loop *CurrentLoop,
710  unsigned Level,
711  FullDependence &Result,
712  Constraint &NewConstraint) const;
713 
714  /// weakZeroDstSIVtest - Tests the weak-zero SIV subscript pair
715  /// (Src and Dst) for dependence.
716  /// Things of the form [c1 + a*i] and [c2],
717  /// where i is an induction variable, c1 and c2 are loop invariant,
718  /// and a is a constant. See also weakZeroSrcSIVtest.
719  /// Returns true if any possible dependence is disproved.
720  /// If there might be a dependence, returns false.
721  /// Sets appropriate direction entry.
722  /// Set consistent to false.
723  /// If loop peeling will break the dependence, mark appropriately.
724  bool weakZeroDstSIVtest(const SCEV *SrcCoeff,
725  const SCEV *SrcConst,
726  const SCEV *DstConst,
727  const Loop *CurrentLoop,
728  unsigned Level,
729  FullDependence &Result,
730  Constraint &NewConstraint) const;
731 
732  /// exactRDIVtest - Tests the RDIV subscript pair for dependence.
733  /// Things of the form [c1 + a*i] and [c2 + b*j],
734  /// where i and j are induction variable, c1 and c2 are loop invariant,
735  /// and a and b are constants.
736  /// Returns true if any possible dependence is disproved.
737  /// Marks the result as inconsistent.
738  /// Works in some cases that symbolicRDIVtest doesn't,
739  /// and vice versa.
740  bool exactRDIVtest(const SCEV *SrcCoeff,
741  const SCEV *DstCoeff,
742  const SCEV *SrcConst,
743  const SCEV *DstConst,
744  const Loop *SrcLoop,
745  const Loop *DstLoop,
746  FullDependence &Result) const;
747 
748  /// symbolicRDIVtest - Tests the RDIV subscript pair for dependence.
749  /// Things of the form [c1 + a*i] and [c2 + b*j],
750  /// where i and j are induction variable, c1 and c2 are loop invariant,
751  /// and a and b are constants.
752  /// Returns true if any possible dependence is disproved.
753  /// Marks the result as inconsistent.
754  /// Works in some cases that exactRDIVtest doesn't,
755  /// and vice versa. Can also be used as a backup for
756  /// ordinary SIV tests.
757  bool symbolicRDIVtest(const SCEV *SrcCoeff,
758  const SCEV *DstCoeff,
759  const SCEV *SrcConst,
760  const SCEV *DstConst,
761  const Loop *SrcLoop,
762  const Loop *DstLoop) const;
763 
764  /// gcdMIVtest - Tests an MIV subscript pair for dependence.
765  /// Returns true if any possible dependence is disproved.
766  /// Marks the result as inconsistent.
767  /// Can sometimes disprove the equal direction for 1 or more loops.
768  // Can handle some symbolics that even the SIV tests don't get,
769  /// so we use it as a backup for everything.
770  bool gcdMIVtest(const SCEV *Src,
771  const SCEV *Dst,
772  FullDependence &Result) const;
773 
774  /// banerjeeMIVtest - Tests an MIV subscript pair for dependence.
775  /// Returns true if any possible dependence is disproved.
776  /// Marks the result as inconsistent.
777  /// Computes directions.
778  bool banerjeeMIVtest(const SCEV *Src,
779  const SCEV *Dst,
780  const SmallBitVector &Loops,
781  FullDependence &Result) const;
782 
783  /// collectCoefficientInfo - Walks through the subscript,
784  /// collecting each coefficient, the associated loop bounds,
785  /// and recording its positive and negative parts for later use.
786  CoefficientInfo *collectCoeffInfo(const SCEV *Subscript,
787  bool SrcFlag,
788  const SCEV *&Constant) const;
789 
790  /// getPositivePart - X^+ = max(X, 0).
791  ///
792  const SCEV *getPositivePart(const SCEV *X) const;
793 
794  /// getNegativePart - X^- = min(X, 0).
795  ///
796  const SCEV *getNegativePart(const SCEV *X) const;
797 
798  /// getLowerBound - Looks through all the bounds info and
799  /// computes the lower bound given the current direction settings
800  /// at each level.
801  const SCEV *getLowerBound(BoundInfo *Bound) const;
802 
803  /// getUpperBound - Looks through all the bounds info and
804  /// computes the upper bound given the current direction settings
805  /// at each level.
806  const SCEV *getUpperBound(BoundInfo *Bound) const;
807 
808  /// exploreDirections - Hierarchically expands the direction vector
809  /// search space, combining the directions of discovered dependences
810  /// in the DirSet field of Bound. Returns the number of distinct
811  /// dependences discovered. If the dependence is disproved,
812  /// it will return 0.
813  unsigned exploreDirections(unsigned Level,
814  CoefficientInfo *A,
815  CoefficientInfo *B,
816  BoundInfo *Bound,
817  const SmallBitVector &Loops,
818  unsigned &DepthExpanded,
819  const SCEV *Delta) const;
820 
821  /// testBounds - Returns true iff the current bounds are plausible.
822  bool testBounds(unsigned char DirKind,
823  unsigned Level,
824  BoundInfo *Bound,
825  const SCEV *Delta) const;
826 
827  /// findBoundsALL - Computes the upper and lower bounds for level K
828  /// using the * direction. Records them in Bound.
829  void findBoundsALL(CoefficientInfo *A,
830  CoefficientInfo *B,
831  BoundInfo *Bound,
832  unsigned K) const;
833 
834  /// findBoundsLT - Computes the upper and lower bounds for level K
835  /// using the < direction. Records them in Bound.
836  void findBoundsLT(CoefficientInfo *A,
837  CoefficientInfo *B,
838  BoundInfo *Bound,
839  unsigned K) const;
840 
841  /// findBoundsGT - Computes the upper and lower bounds for level K
842  /// using the > direction. Records them in Bound.
843  void findBoundsGT(CoefficientInfo *A,
844  CoefficientInfo *B,
845  BoundInfo *Bound,
846  unsigned K) const;
847 
848  /// findBoundsEQ - Computes the upper and lower bounds for level K
849  /// using the = direction. Records them in Bound.
850  void findBoundsEQ(CoefficientInfo *A,
851  CoefficientInfo *B,
852  BoundInfo *Bound,
853  unsigned K) const;
854 
855  /// intersectConstraints - Updates X with the intersection
856  /// of the Constraints X and Y. Returns true if X has changed.
857  bool intersectConstraints(Constraint *X,
858  const Constraint *Y);
859 
860  /// propagate - Review the constraints, looking for opportunities
861  /// to simplify a subscript pair (Src and Dst).
862  /// Return true if some simplification occurs.
863  /// If the simplification isn't exact (that is, if it is conservative
864  /// in terms of dependence), set consistent to false.
865  bool propagate(const SCEV *&Src,
866  const SCEV *&Dst,
867  SmallBitVector &Loops,
868  SmallVectorImpl<Constraint> &Constraints,
869  bool &Consistent);
870 
871  /// propagateDistance - Attempt to propagate a distance
872  /// constraint into a subscript pair (Src and Dst).
873  /// Return true if some simplification occurs.
874  /// If the simplification isn't exact (that is, if it is conservative
875  /// in terms of dependence), set consistent to false.
876  bool propagateDistance(const SCEV *&Src,
877  const SCEV *&Dst,
878  Constraint &CurConstraint,
879  bool &Consistent);
880 
881  /// propagatePoint - Attempt to propagate a point
882  /// constraint into a subscript pair (Src and Dst).
883  /// Return true if some simplification occurs.
884  bool propagatePoint(const SCEV *&Src,
885  const SCEV *&Dst,
886  Constraint &CurConstraint);
887 
888  /// propagateLine - Attempt to propagate a line
889  /// constraint into a subscript pair (Src and Dst).
890  /// Return true if some simplification occurs.
891  /// If the simplification isn't exact (that is, if it is conservative
892  /// in terms of dependence), set consistent to false.
893  bool propagateLine(const SCEV *&Src,
894  const SCEV *&Dst,
895  Constraint &CurConstraint,
896  bool &Consistent);
897 
898  /// findCoefficient - Given a linear SCEV,
899  /// return the coefficient corresponding to specified loop.
900  /// If there isn't one, return the SCEV constant 0.
901  /// For example, given a*i + b*j + c*k, returning the coefficient
902  /// corresponding to the j loop would yield b.
903  const SCEV *findCoefficient(const SCEV *Expr,
904  const Loop *TargetLoop) const;
905 
906  /// zeroCoefficient - Given a linear SCEV,
907  /// return the SCEV given by zeroing out the coefficient
908  /// corresponding to the specified loop.
909  /// For example, given a*i + b*j + c*k, zeroing the coefficient
910  /// corresponding to the j loop would yield a*i + c*k.
911  const SCEV *zeroCoefficient(const SCEV *Expr,
912  const Loop *TargetLoop) const;
913 
914  /// addToCoefficient - Given a linear SCEV Expr,
915  /// return the SCEV given by adding some Value to the
916  /// coefficient corresponding to the specified TargetLoop.
917  /// For example, given a*i + b*j + c*k, adding 1 to the coefficient
918  /// corresponding to the j loop would yield a*i + (b+1)*j + c*k.
919  const SCEV *addToCoefficient(const SCEV *Expr,
920  const Loop *TargetLoop,
921  const SCEV *Value) const;
922 
923  /// updateDirection - Update direction vector entry
924  /// based on the current constraint.
925  void updateDirection(Dependence::DVEntry &Level,
926  const Constraint &CurConstraint) const;
927 
928  /// Given a linear access function, tries to recover subscripts
929  /// for each dimension of the array element access.
930  bool tryDelinearize(Instruction *Src, Instruction *Dst,
931  SmallVectorImpl<Subscript> &Pair);
932 
933  /// Tries to delinearize access function for a fixed size multi-dimensional
934  /// array, by deriving subscripts from GEP instructions. Returns true upon
935  /// success and false otherwise.
936  bool tryDelinearizeFixedSize(Instruction *Src, Instruction *Dst,
937  const SCEV *SrcAccessFn,
938  const SCEV *DstAccessFn,
939  SmallVectorImpl<const SCEV *> &SrcSubscripts,
940  SmallVectorImpl<const SCEV *> &DstSubscripts);
941 
942  /// Tries to delinearize access function for a multi-dimensional array with
943  /// symbolic runtime sizes.
944  /// Returns true upon success and false otherwise.
945  bool tryDelinearizeParametricSize(
946  Instruction *Src, Instruction *Dst, const SCEV *SrcAccessFn,
947  const SCEV *DstAccessFn, SmallVectorImpl<const SCEV *> &SrcSubscripts,
948  SmallVectorImpl<const SCEV *> &DstSubscripts);
949 
950  /// checkSubscript - Helper function for checkSrcSubscript and
951  /// checkDstSubscript to avoid duplicate code
952  bool checkSubscript(const SCEV *Expr, const Loop *LoopNest,
953  SmallBitVector &Loops, bool IsSrc);
954  }; // class DependenceInfo
955 
956  /// AnalysisPass to compute dependence information in a function
957  class DependenceAnalysis : public AnalysisInfoMixin<DependenceAnalysis> {
958  public:
961 
962  private:
963  static AnalysisKey Key;
965  }; // class DependenceAnalysis
966 
967  /// Printer pass to dump DA results.
969  : public PassInfoMixin<DependenceAnalysisPrinterPass> {
971 
973 
974  private:
975  raw_ostream &OS;
976  }; // class DependenceAnalysisPrinterPass
977 
978  /// Legacy pass manager pass to access dependence information
980  public:
981  static char ID; // Class identification, replacement for typeinfo
983 
984  bool runOnFunction(Function &F) override;
985  void releaseMemory() override;
986  void getAnalysisUsage(AnalysisUsage &) const override;
987  void print(raw_ostream &, const Module * = nullptr) const override;
988  DependenceInfo &getDI() const;
989 
990  private:
991  std::unique_ptr<DependenceInfo> info;
992  }; // class DependenceAnalysisWrapperPass
993 
994  /// createDependenceAnalysisPass - This creates an instance of the
995  /// DependenceAnalysis wrapper pass.
997 
998 } // namespace llvm
999 
1000 #endif
llvm::Check::Size
@ Size
Definition: FileCheck.h:73
llvm::PreservedAnalyses
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:155
llvm::Dependence::isSplitable
virtual bool isSplitable(unsigned Level) const
isSplitable - Returns true if splitting this loop will break the dependence.
Definition: DependenceAnalysis.h:174
llvm::Dependence::DVEntry::NONE
@ NONE
Definition: DependenceAnalysis.h:89
llvm::FullDependence::isConfused
bool isConfused() const override
isConfused - Returns true if this dependence is confused (the compiler understands nothing and makes ...
Definition: DependenceAnalysis.h:227
llvm
This file implements support for optimizing divisions by a constant.
Definition: AllocatorList.h:23
llvm::Dependence::isFlow
bool isFlow() const
isFlow - Returns true if this is a flow (aka true) dependence.
Definition: DependenceAnalysis.cpp:239
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:231
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:172
llvm::CmpInst::Predicate
Predicate
This enumeration lists the possible predicates for CmpInst subclasses.
Definition: InstrTypes.h:720
llvm::PassInfoMixin
A CRTP mix-in to automatically provide informational APIs needed for passes.
Definition: PassManager.h:374
llvm::DependenceAnalysisWrapperPass
Legacy pass manager pass to access dependence information.
Definition: DependenceAnalysis.h:979
llvm::Function
Definition: Function.h:62
Pass.h
Loops
Hexagon Hardware Loops
Definition: HexagonHardwareLoops.cpp:372
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:154
llvm::Dependence::dump
void dump(raw_ostream &OS) const
dump - For debugging purposes, dumps a dependence to OS.
Definition: DependenceAnalysis.cpp:597
llvm::FullDependence::isSplitable
bool isSplitable(unsigned Level) const override
isSplitable - Returns true if splitting the loop will break the dependence.
Definition: DependenceAnalysis.cpp:314
llvm::DependenceInfo::getFunction
Function * getFunction() const
Definition: DependenceAnalysis.h:334
llvm::DependenceInfo::DependenceInfo
DependenceInfo(Function *F, AAResults *AA, ScalarEvolution *SE, LoopInfo *LI)
Definition: DependenceAnalysis.h:274
llvm::ScalarEvolution
The main scalar evolution driver.
Definition: ScalarEvolution.h:460
llvm::Dependence::DVEntry::GE
@ GE
Definition: DependenceAnalysis.h:95
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
llvm::Dependence::DVEntry::ALL
@ ALL
Definition: DependenceAnalysis.h:96
llvm::Dependence::isUnordered
bool isUnordered() const
isUnordered - Returns true if dependence is Input
Definition: DependenceAnalysis.h:137
llvm::DependenceAnalysisWrapperPass::getDI
DependenceInfo & getDI() const
Definition: DependenceAnalysis.cpp:168
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:254
llvm::DependenceAnalysisWrapperPass::ID
static char ID
Definition: DependenceAnalysis.h:981
llvm::Dependence::DVEntry::LT
@ LT
Definition: DependenceAnalysis.h:90
llvm::DependenceAnalysisWrapperPass::print
void print(raw_ostream &, const Module *=nullptr) const override
print - Print out the internal state of the pass.
Definition: DependenceAnalysis.cpp:211
llvm::dump
void dump(const SparseBitVector< ElementSize > &LHS, raw_ostream &out)
Definition: SparseBitVector.h:876
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:299
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:291
llvm::Dependence::DVEntry::Distance
const SCEV * Distance
Definition: DependenceAnalysis.h:102
llvm::Dependence::isAnti
bool isAnti() const
isAnti - Returns true if this is an anti dependence.
Definition: DependenceAnalysis.cpp:245
F
#define F(x, y, z)
Definition: MD5.cpp:56
llvm::Dependence::DVEntry
Dependence::DVEntry - Each level in the distance/direction vector has a direction (or perhaps a union...
Definition: DependenceAnalysis.h:88
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:170
llvm::DependenceAnalysisWrapperPass::DependenceAnalysisWrapperPass
DependenceAnalysisWrapperPass()
Definition: DependenceAnalysis.cpp:151
llvm::AAResults
Definition: AliasAnalysis.h:508
llvm::FullDependence::FullDependence
FullDependence(Instruction *Src, Instruction *Dst, bool LoopIndependent, unsigned Levels)
Definition: DependenceAnalysis.cpp:262
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:156
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:142
B
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
llvm::Instruction
Definition: Instruction.h:45
llvm::Dependence::isConfused
virtual bool isConfused() const
isConfused - Returns true if this dependence is confused (the compiler understands nothing and makes ...
Definition: DependenceAnalysis.h:146
llvm::raw_ostream
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:53
llvm::Dependence::getDistance
virtual const SCEV * getDistance(unsigned Level) const
getDistance - Returns the distance (or NULL) associated with a particular level.
Definition: DependenceAnalysis.h:162
llvm::AnalysisManager::Invalidator
API to communicate dependencies between analyses during invalidation.
Definition: PassManager.h:670
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:3500
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:3959
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:233
llvm::DependenceAnalysisPrinterPass
Printer pass to dump DA results.
Definition: DependenceAnalysis.h:968
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:77
llvm::DependenceInfo
DependenceInfo - This class is the main dependence-analysis driver.
Definition: DependenceAnalysis.h:272
llvm::Dependence::DVEntry::Scalar
bool Scalar
Definition: DependenceAnalysis.h:98
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:72
llvm::pdb::Empty
@ Empty
Definition: PDBTypes.h:394
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:170
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:150
llvm::Dependence::DVEntry::LE
@ LE
Definition: DependenceAnalysis.h:92
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:282
llvm::Module
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:67
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:166
llvm::AnalysisInfoMixin
A CRTP mix-in that provides informational APIs needed for analysis passes.
Definition: PassManager.h:397
llvm::Dependence::getDst
Instruction * getDst() const
getDst - Returns the destination instruction for this dependence.
Definition: DependenceAnalysis.h:113
llvm::Dependence::isInput
bool isInput() const
isInput - Returns true if this is an input dependence.
Definition: DependenceAnalysis.cpp:227
llvm::Sched::Source
@ Source
Definition: TargetLowering.h:100
llvm::LoopInfo
Definition: LoopInfo.h:1083
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:307
llvm::DependenceAnalysis
AnalysisPass to compute dependence information in a function.
Definition: DependenceAnalysis.h:957
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::NE
@ NE
Definition: DependenceAnalysis.h:94
llvm::Dependence::DVEntry::Direction
unsigned char Direction
Definition: DependenceAnalysis.h:97
llvm::Dependence::setNextPredecessor
void setNextPredecessor(const Dependence *pred)
setNextPredecessor - Sets the value of the NextPredecessor field.
Definition: DependenceAnalysis.h:191
llvm::DependenceAnalysis::run
Result run(Function &F, FunctionAnalysisManager &FAM)
Definition: DependenceAnalysis.cpp:132
llvm::Dependence::setNextSuccessor
void setNextSuccessor(const Dependence *succ)
setNextSuccessor - Sets the value of the NextSuccessor field.
Definition: DependenceAnalysis.h:195
llvm::SystemZICMP::Any
@ Any
Definition: SystemZISelLowering.h:374
llvm::Dependence::DVEntry::Splitable
bool Splitable
Definition: DependenceAnalysis.h:101
Direction
Loop::LoopBounds::Direction Direction
Definition: LoopInfo.cpp:230
llvm::TargetStackID::Value
Value
Definition: TargetFrameLowering.h:27
PassManager.h
llvm::Dependence::DVEntry::GT
@ GT
Definition: DependenceAnalysis.h:93
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:3525
llvm::Dependence::getDirection
virtual unsigned getDirection(unsigned Level) const
getDirection - Returns the direction associated with a particular level.
Definition: DependenceAnalysis.h:158
Instructions.h
llvm::Dependence::DVEntry::EQ
@ EQ
Definition: DependenceAnalysis.h:91
llvm::Dependence::isOrdered
bool isOrdered() const
isOrdered - Returns true if dependence is Output, Flow, or Anti
Definition: DependenceAnalysis.h:133
llvm::Dependence::~Dependence
virtual ~Dependence()
Definition: DependenceAnalysis.h:83
SmallBitVector.h
llvm::Dependence::getNextPredecessor
const Dependence * getNextPredecessor() const
getNextPredecessor - Returns the value of the NextPredecessor field.
Definition: DependenceAnalysis.h:183
llvm::FullDependence::isLoopIndependent
bool isLoopIndependent() const override
isLoopIndependent - Returns true if this is a loop-independent dependence.
Definition: DependenceAnalysis.h:222
llvm::FullDependence::getDirection
unsigned getDirection(unsigned Level) const override
getDirection - Returns the direction associated with a particular level.
Definition: DependenceAnalysis.cpp:275
llvm::AnalysisManager
A container for analyses that lazily runs them and caches their results.
Definition: InstructionSimplify.h:44
pred
hexagon gen pred
Definition: HexagonGenPredicate.cpp:134
llvm::FunctionPass
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:298
llvm::Dependence::DVEntry::DVEntry
DVEntry()
Definition: DependenceAnalysis.h:103
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:235
llvm::DependenceAnalysis::Result
DependenceInfo Result
Definition: DependenceAnalysis.h:959
true
basic Basic Alias true
Definition: BasicAliasAnalysis.cpp:1903
llvm::Dependence::isLoopIndependent
virtual bool isLoopIndependent() const
isLoopIndependent - Returns true if this is a loop-independent dependence.
Definition: DependenceAnalysis.h:141
llvm::DependenceAnalysisPrinterPass::DependenceAnalysisPrinterPass
DependenceAnalysisPrinterPass(raw_ostream &OS)
Definition: DependenceAnalysis.h:970
llvm::Dependence::getNextSuccessor
const Dependence * getNextSuccessor() const
getNextSuccessor - Returns the value of the NextSuccessor field.
Definition: DependenceAnalysis.h:187
llvm::DependenceAnalysisPrinterPass::run
PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM)
Definition: DependenceAnalysis.cpp:217
llvm::Dependence::getSrc
Instruction * getSrc() const
getSrc - Returns the source instruction for this dependence.
Definition: DependenceAnalysis.h:109
llvm::FullDependence
FullDependence - This class represents a dependence between two memory references in a function.
Definition: DependenceAnalysis.h:215
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:160
llvm::Dependence::DVEntry::PeelFirst
bool PeelFirst
Definition: DependenceAnalysis.h:99
llvm::Dependence::DVEntry::PeelLast
bool PeelLast
Definition: DependenceAnalysis.h:100