1 /* Data references and dependences detectors.
2 Copyright (C) 2003-2023 Free Software Foundation, Inc.
3 Contributed by Sebastian Pop <pop@cri.ensmp.fr>
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
11
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
20
21 #ifndef GCC_TREE_DATA_REF_H
22 #define GCC_TREE_DATA_REF_H
23
24 #include "graphds.h"
25 #include "tree-chrec.h"
26 #include "opt-problem.h"
27
28 /*
29 innermost_loop_behavior describes the evolution of the address of the memory
30 reference in the innermost enclosing loop. The address is expressed as
31 BASE + STEP * # of iteration, and base is further decomposed as the base
32 pointer (BASE_ADDRESS), loop invariant offset (OFFSET) and
33 constant offset (INIT). Examples, in loop nest
34
35 for (i = 0; i < 100; i++)
36 for (j = 3; j < 100; j++)
37
38 Example 1 Example 2
39 data-ref a[j].b[i][j] *(p + x + 16B + 4B * j)
40
41
42 innermost_loop_behavior
43 base_address &a p
44 offset i * D_i x
45 init 3 * D_j + offsetof (b) 28
46 step D_j 4
47
48 */
49 struct innermost_loop_behavior
50 {
51 tree base_address;
52 tree offset;
53 tree init;
54 tree step;
55
56 /* BASE_ADDRESS is known to be misaligned by BASE_MISALIGNMENT bytes
57 from an alignment boundary of BASE_ALIGNMENT bytes. For example,
58 if we had:
59
60 struct S __attribute__((aligned(16))) { ... };
61
62 char *ptr;
63 ... *(struct S *) (ptr - 4) ...;
64
65 the information would be:
66
67 base_address: ptr
68 base_aligment: 16
69 base_misalignment: 4
70 init: -4
71
72 where init cancels the base misalignment. If instead we had a
73 reference to a particular field:
74
75 struct S __attribute__((aligned(16))) { ... int f; ... };
76
77 char *ptr;
78 ... ((struct S *) (ptr - 4))->f ...;
79
80 the information would be:
81
82 base_address: ptr
83 base_aligment: 16
84 base_misalignment: 4
85 init: -4 + offsetof (S, f)
86
87 where base_address + init might also be misaligned, and by a different
88 amount from base_address. */
89 unsigned int base_alignment;
90 unsigned int base_misalignment;
91
92 /* The largest power of two that divides OFFSET, capped to a suitably
93 high value if the offset is zero. This is a byte rather than a bit
94 quantity. */
95 unsigned int offset_alignment;
96
97 /* Likewise for STEP. */
98 unsigned int step_alignment;
99 };
100
101 /* Describes the evolutions of indices of the memory reference. The indices
102 are indices of the ARRAY_REFs, indexes in artificial dimensions
103 added for member selection of records and the operands of MEM_REFs.
104 BASE_OBJECT is the part of the reference that is loop-invariant
105 (note that this reference does not have to cover the whole object
106 being accessed, in which case UNCONSTRAINED_BASE is set; hence it is
107 not recommended to use BASE_OBJECT in any code generation).
108 For the examples above,
109
110 base_object: a *(p + x + 4B * j_0)
111 indices: {j_0, +, 1}_2 {16, +, 4}_2
112 4
113 {i_0, +, 1}_1
114 {j_0, +, 1}_2
115 */
116
117 struct indices
118 {
119 /* The object. */
120 tree base_object;
121
122 /* A list of chrecs. Access functions of the indices. */
123 vec<tree> access_fns;
124
125 /* Whether BASE_OBJECT is an access representing the whole object
126 or whether the access could not be constrained. */
127 bool unconstrained_base;
128 };
129
130 struct dr_alias
131 {
132 /* The alias information that should be used for new pointers to this
133 location. */
134 struct ptr_info_def *ptr_info;
135 };
136
137 /* An integer vector. A vector formally consists of an element of a vector
138 space. A vector space is a set that is closed under vector addition
139 and scalar multiplication. In this vector space, an element is a list of
140 integers. */
141 typedef HOST_WIDE_INT lambda_int;
142 typedef lambda_int *lambda_vector;
143
144 /* An integer matrix. A matrix consists of m vectors of length n (IE
145 all vectors are the same length). */
146 typedef lambda_vector *lambda_matrix;
147
148
149
150 struct data_reference
151 {
152 /* A pointer to the statement that contains this DR. */
153 gimple *stmt;
154
155 /* A pointer to the memory reference. */
156 tree ref;
157
158 /* Auxiliary info specific to a pass. */
159 void *aux;
160
161 /* True when the data reference is in RHS of a stmt. */
162 bool is_read;
163
164 /* True when the data reference is conditional within STMT,
165 i.e. if it might not occur even when the statement is executed
166 and runs to completion. */
167 bool is_conditional_in_stmt;
168
169 /* Alias information for the data reference. */
170 struct dr_alias alias;
171
172 /* Behavior of the memory reference in the innermost loop. */
173 struct innermost_loop_behavior innermost;
174
175 /* Subscripts of this data reference. */
176 struct indices indices;
177
178 /* Alternate subscripts initialized lazily and used by data-dependence
179 analysis only when the main indices of two DRs are not comparable.
180 Keep last to keep vec_info_shared::check_datarefs happy. */
181 struct indices alt_indices;
182 };
183
184 #define DR_STMT(DR) (DR)->stmt
185 #define DR_REF(DR) (DR)->ref
186 #define DR_BASE_OBJECT(DR) (DR)->indices.base_object
187 #define DR_UNCONSTRAINED_BASE(DR) (DR)->indices.unconstrained_base
188 #define DR_ACCESS_FNS(DR) (DR)->indices.access_fns
189 #define DR_ACCESS_FN(DR, I) DR_ACCESS_FNS (DR)[I]
190 #define DR_NUM_DIMENSIONS(DR) DR_ACCESS_FNS (DR).length ()
191 #define DR_IS_READ(DR) (DR)->is_read
192 #define DR_IS_WRITE(DR) (!DR_IS_READ (DR))
193 #define DR_IS_CONDITIONAL_IN_STMT(DR) (DR)->is_conditional_in_stmt
194 #define DR_BASE_ADDRESS(DR) (DR)->innermost.base_address
195 #define DR_OFFSET(DR) (DR)->innermost.offset
196 #define DR_INIT(DR) (DR)->innermost.init
197 #define DR_STEP(DR) (DR)->innermost.step
198 #define DR_PTR_INFO(DR) (DR)->alias.ptr_info
199 #define DR_BASE_ALIGNMENT(DR) (DR)->innermost.base_alignment
200 #define DR_BASE_MISALIGNMENT(DR) (DR)->innermost.base_misalignment
201 #define DR_OFFSET_ALIGNMENT(DR) (DR)->innermost.offset_alignment
202 #define DR_STEP_ALIGNMENT(DR) (DR)->innermost.step_alignment
203 #define DR_INNERMOST(DR) (DR)->innermost
204
205 typedef struct data_reference *data_reference_p;
206
207 /* This struct is used to store the information of a data reference,
208 including the data ref itself and the segment length for aliasing
209 checks. This is used to merge alias checks. */
210
211 class dr_with_seg_len
212 {
213 public:
214 dr_with_seg_len (data_reference_p d, tree len, unsigned HOST_WIDE_INT size,
215 unsigned int a)
216 : dr (d), seg_len (len), access_size (size), align (a) {}
217
218 data_reference_p dr;
219 /* The offset of the last access that needs to be checked minus
220 the offset of the first. */
221 tree seg_len;
222 /* A value that, when added to abs (SEG_LEN), gives the total number of
223 bytes in the segment. */
224 poly_uint64 access_size;
225 /* The minimum common alignment of DR's start address, SEG_LEN and
226 ACCESS_SIZE. */
227 unsigned int align;
228 };
229
230 /* Flags that describe a potential alias between two dr_with_seg_lens.
231 In general, each pair of dr_with_seg_lens represents a composite of
232 multiple access pairs P, so testing flags like DR_IS_READ on the DRs
233 does not give meaningful information.
234
235 DR_ALIAS_RAW:
236 There is a pair in P for which the second reference is a read
237 and the first is a write.
238
239 DR_ALIAS_WAR:
240 There is a pair in P for which the second reference is a write
241 and the first is a read.
242
243 DR_ALIAS_WAW:
244 There is a pair in P for which both references are writes.
245
246 DR_ALIAS_ARBITRARY:
247 Either
248 (a) it isn't possible to classify one pair in P as RAW, WAW or WAR; or
249 (b) there is a pair in P that breaks the ordering assumption below.
250
251 This flag overrides the RAW, WAR and WAW flags above.
252
253 DR_ALIAS_UNSWAPPED:
254 DR_ALIAS_SWAPPED:
255 Temporary flags that indicate whether there is a pair P whose
256 DRs have or haven't been swapped around.
257
258 DR_ALIAS_MIXED_STEPS:
259 The DR_STEP for one of the data references in the pair does not
260 accurately describe that reference for all members of P. (Note
261 that the flag does not say anything about whether the DR_STEPs
262 of the two references in the pair are the same.)
263
264 The ordering assumption mentioned above is that for every pair
265 (DR_A, DR_B) in P:
266
267 (1) The original code accesses n elements for DR_A and n elements for DR_B,
268 interleaved as follows:
269
270 one access of size DR_A.access_size at DR_A.dr
271 one access of size DR_B.access_size at DR_B.dr
272 one access of size DR_A.access_size at DR_A.dr + STEP_A
273 one access of size DR_B.access_size at DR_B.dr + STEP_B
274 one access of size DR_A.access_size at DR_A.dr + STEP_A * 2
275 one access of size DR_B.access_size at DR_B.dr + STEP_B * 2
276 ...
277
278 (2) The new code accesses the same data in exactly two chunks:
279
280 one group of accesses spanning |DR_A.seg_len| + DR_A.access_size
281 one group of accesses spanning |DR_B.seg_len| + DR_B.access_size
282
283 A pair might break this assumption if the DR_A and DR_B accesses
284 in the original or the new code are mingled in some way. For example,
285 if DR_A.access_size represents the effect of two individual writes
286 to nearby locations, the pair breaks the assumption if those writes
287 occur either side of the access for DR_B.
288
289 Note that DR_ALIAS_ARBITRARY describes whether the ordering assumption
290 fails to hold for any individual pair in P. If the assumption *does*
291 hold for every pair in P, it doesn't matter whether it holds for the
292 composite pair or not. In other words, P should represent the complete
293 set of pairs that the composite pair is testing, so only the ordering
294 of two accesses in the same member of P matters. */
295 const unsigned int DR_ALIAS_RAW = 1U << 0;
296 const unsigned int DR_ALIAS_WAR = 1U << 1;
297 const unsigned int DR_ALIAS_WAW = 1U << 2;
298 const unsigned int DR_ALIAS_ARBITRARY = 1U << 3;
299 const unsigned int DR_ALIAS_SWAPPED = 1U << 4;
300 const unsigned int DR_ALIAS_UNSWAPPED = 1U << 5;
301 const unsigned int DR_ALIAS_MIXED_STEPS = 1U << 6;
302
303 /* This struct contains two dr_with_seg_len objects with aliasing data
304 refs. Two comparisons are generated from them. */
305
306 class dr_with_seg_len_pair_t
307 {
308 public:
309 /* WELL_ORDERED indicates that the ordering assumption described above
310 DR_ALIAS_ARBITRARY holds. REORDERED indicates that it doesn't. */
311 enum sequencing { WELL_ORDERED, REORDERED };
312
313 dr_with_seg_len_pair_t (const dr_with_seg_len &,
314 const dr_with_seg_len &, sequencing);
315
316 dr_with_seg_len first;
317 dr_with_seg_len second;
318 unsigned int flags;
319 };
320
321 inline dr_with_seg_len_pair_t::
322 dr_with_seg_len_pair_t (const dr_with_seg_len &d1, const dr_with_seg_len &d2,
323 sequencing seq)
324 : first (d1), second (d2), flags (0)
325 {
326 if (DR_IS_READ (d1.dr) && DR_IS_WRITE (d2.dr))
327 flags |= DR_ALIAS_WAR;
328 else if (DR_IS_WRITE (d1.dr) && DR_IS_READ (d2.dr))
329 flags |= DR_ALIAS_RAW;
330 else if (DR_IS_WRITE (d1.dr) && DR_IS_WRITE (d2.dr))
331 flags |= DR_ALIAS_WAW;
332 else
333 gcc_unreachable ();
334 if (seq == REORDERED)
335 flags |= DR_ALIAS_ARBITRARY;
336 }
337
338 enum data_dependence_direction {
339 dir_positive,
340 dir_negative,
341 dir_equal,
342 dir_positive_or_negative,
343 dir_positive_or_equal,
344 dir_negative_or_equal,
345 dir_star,
346 dir_independent
347 };
348
349 /* The description of the grid of iterations that overlap. At most
350 two loops are considered at the same time just now, hence at most
351 two functions are needed. For each of the functions, we store
352 the vector of coefficients, f[0] + x * f[1] + y * f[2] + ...,
353 where x, y, ... are variables. */
354
355 #define MAX_DIM 2
356
357 /* Special values of N. */
358 #define NO_DEPENDENCE 0
359 #define NOT_KNOWN (MAX_DIM + 1)
360 #define CF_NONTRIVIAL_P(CF) ((CF)->n != NO_DEPENDENCE && (CF)->n != NOT_KNOWN)
361 #define CF_NOT_KNOWN_P(CF) ((CF)->n == NOT_KNOWN)
362 #define CF_NO_DEPENDENCE_P(CF) ((CF)->n == NO_DEPENDENCE)
363
364 typedef vec<tree> affine_fn;
365
366 struct conflict_function
367 {
368 unsigned n;
369 affine_fn fns[MAX_DIM];
370 };
371
372 /* What is a subscript? Given two array accesses a subscript is the
373 tuple composed of the access functions for a given dimension.
374 Example: Given A[f1][f2][f3] and B[g1][g2][g3], there are three
375 subscripts: (f1, g1), (f2, g2), (f3, g3). These three subscripts
376 are stored in the data_dependence_relation structure under the form
377 of an array of subscripts. */
378
379 struct subscript
380 {
381 /* The access functions of the two references. */
382 tree access_fn[2];
383
384 /* A description of the iterations for which the elements are
385 accessed twice. */
386 conflict_function *conflicting_iterations_in_a;
387 conflict_function *conflicting_iterations_in_b;
388
389 /* This field stores the information about the iteration domain
390 validity of the dependence relation. */
391 tree last_conflict;
392
393 /* Distance from the iteration that access a conflicting element in
394 A to the iteration that access this same conflicting element in
395 B. The distance is a tree scalar expression, i.e. a constant or a
396 symbolic expression, but certainly not a chrec function. */
397 tree distance;
398 };
399
400 typedef struct subscript *subscript_p;
401
402 #define SUB_ACCESS_FN(SUB, I) (SUB)->access_fn[I]
403 #define SUB_CONFLICTS_IN_A(SUB) (SUB)->conflicting_iterations_in_a
404 #define SUB_CONFLICTS_IN_B(SUB) (SUB)->conflicting_iterations_in_b
405 #define SUB_LAST_CONFLICT(SUB) (SUB)->last_conflict
406 #define SUB_DISTANCE(SUB) (SUB)->distance
407
408 /* A data_dependence_relation represents a relation between two
409 data_references A and B. */
410
411 struct data_dependence_relation
412 {
413
414 struct data_reference *a;
415 struct data_reference *b;
416
417 /* A "yes/no/maybe" field for the dependence relation:
418
419 - when "ARE_DEPENDENT == NULL_TREE", there exist a dependence
420 relation between A and B, and the description of this relation
421 is given in the SUBSCRIPTS array,
422
423 - when "ARE_DEPENDENT == chrec_known", there is no dependence and
424 SUBSCRIPTS is empty,
425
426 - when "ARE_DEPENDENT == chrec_dont_know", there may be a dependence,
427 but the analyzer cannot be more specific. */
428 tree are_dependent;
429
430 /* If nonnull, COULD_BE_INDEPENDENT_P is true and the accesses are
431 independent when the runtime addresses of OBJECT_A and OBJECT_B
432 are different. The addresses of both objects are invariant in the
433 loop nest. */
434 tree object_a;
435 tree object_b;
436
437 /* For each subscript in the dependence test, there is an element in
438 this array. This is the attribute that labels the edge A->B of
439 the data_dependence_relation. */
440 vec<subscript_p> subscripts;
441
442 /* The analyzed loop nest. */
443 vec<loop_p> loop_nest;
444
445 /* The classic direction vector. */
446 vec<lambda_vector> dir_vects;
447
448 /* The classic distance vector. */
449 vec<lambda_vector> dist_vects;
450
451 /* Is the dependence reversed with respect to the lexicographic order? */
452 bool reversed_p;
453
454 /* When the dependence relation is affine, it can be represented by
455 a distance vector. */
456 bool affine_p;
457
458 /* Set to true when the dependence relation is on the same data
459 access. */
460 bool self_reference_p;
461
462 /* True if the dependence described is conservatively correct rather
463 than exact, and if it is still possible for the accesses to be
464 conditionally independent. For example, the a and b references in:
465
466 struct s *a, *b;
467 for (int i = 0; i < n; ++i)
468 a->f[i] += b->f[i];
469
470 conservatively have a distance vector of (0), for the case in which
471 a == b, but the accesses are independent if a != b. Similarly,
472 the a and b references in:
473
474 struct s *a, *b;
475 for (int i = 0; i < n; ++i)
476 a[0].f[i] += b[i].f[i];
477
478 conservatively have a distance vector of (0), but they are indepenent
479 when a != b + i. In contrast, the references in:
480
481 struct s *a;
482 for (int i = 0; i < n; ++i)
483 a->f[i] += a->f[i];
484
485 have the same distance vector of (0), but the accesses can never be
486 independent. */
487 bool could_be_independent_p;
488 };
489
490 typedef struct data_dependence_relation *ddr_p;
491
492 #define DDR_A(DDR) (DDR)->a
493 #define DDR_B(DDR) (DDR)->b
494 #define DDR_AFFINE_P(DDR) (DDR)->affine_p
495 #define DDR_ARE_DEPENDENT(DDR) (DDR)->are_dependent
496 #define DDR_OBJECT_A(DDR) (DDR)->object_a
497 #define DDR_OBJECT_B(DDR) (DDR)->object_b
498 #define DDR_SUBSCRIPTS(DDR) (DDR)->subscripts
499 #define DDR_SUBSCRIPT(DDR, I) DDR_SUBSCRIPTS (DDR)[I]
500 #define DDR_NUM_SUBSCRIPTS(DDR) DDR_SUBSCRIPTS (DDR).length ()
501
502 #define DDR_LOOP_NEST(DDR) (DDR)->loop_nest
503 /* The size of the direction/distance vectors: the number of loops in
504 the loop nest. */
505 #define DDR_NB_LOOPS(DDR) (DDR_LOOP_NEST (DDR).length ())
506 #define DDR_SELF_REFERENCE(DDR) (DDR)->self_reference_p
507
508 #define DDR_DIST_VECTS(DDR) ((DDR)->dist_vects)
509 #define DDR_DIR_VECTS(DDR) ((DDR)->dir_vects)
510 #define DDR_NUM_DIST_VECTS(DDR) \
511 (DDR_DIST_VECTS (DDR).length ())
512 #define DDR_NUM_DIR_VECTS(DDR) \
513 (DDR_DIR_VECTS (DDR).length ())
514 #define DDR_DIR_VECT(DDR, I) \
515 DDR_DIR_VECTS (DDR)[I]
516 #define DDR_DIST_VECT(DDR, I) \
517 DDR_DIST_VECTS (DDR)[I]
518 #define DDR_REVERSED_P(DDR) (DDR)->reversed_p
519 #define DDR_COULD_BE_INDEPENDENT_P(DDR) (DDR)->could_be_independent_p
520
521
522 opt_result dr_analyze_innermost (innermost_loop_behavior *, tree,
523 class loop *, const gimple *);
524 extern bool compute_data_dependences_for_loop (class loop *, bool,
525 vec<loop_p> *,
526 vec<data_reference_p> *,
527 vec<ddr_p> *);
528 extern void debug_ddrs (vec<ddr_p> );
529 extern void dump_data_reference (FILE *, struct data_reference *);
530 extern void debug (data_reference &ref);
531 extern void debug (data_reference *ptr);
532 extern void debug_data_reference (struct data_reference *);
533 extern void debug_data_references (vec<data_reference_p> );
534 extern void debug (vec<data_reference_p> &ref);
535 extern void debug (vec<data_reference_p> *ptr);
536 extern void debug_data_dependence_relation (const data_dependence_relation *);
537 extern void dump_data_dependence_relations (FILE *, const vec<ddr_p> &);
538 extern void debug (vec<ddr_p> &ref);
539 extern void debug (vec<ddr_p> *ptr);
540 extern void debug_data_dependence_relations (vec<ddr_p> );
541 extern void free_dependence_relation (struct data_dependence_relation *);
542 extern void free_dependence_relations (vec<ddr_p>& );
543 extern void free_data_ref (data_reference_p);
544 extern void free_data_refs (vec<data_reference_p>& );
545 extern opt_result find_data_references_in_stmt (class loop *, gimple *,
546 vec<data_reference_p> *);
547 extern bool graphite_find_data_references_in_stmt (edge, loop_p, gimple *,
548 vec<data_reference_p> *);
549 tree find_data_references_in_loop (class loop *, vec<data_reference_p> *);
550 bool loop_nest_has_data_refs (loop_p loop);
551 struct data_reference *create_data_ref (edge, loop_p, tree, gimple *, bool,
552 bool);
553 extern bool find_loop_nest (class loop *, vec<loop_p> *);
554 extern struct data_dependence_relation *initialize_data_dependence_relation
555 (struct data_reference *, struct data_reference *, vec<loop_p>);
556 extern void compute_affine_dependence (struct data_dependence_relation *,
557 loop_p);
558 extern void compute_self_dependence (struct data_dependence_relation *);
559 extern bool compute_all_dependences (const vec<data_reference_p> &,
560 vec<ddr_p> *,
561 const vec<loop_p> &, bool);
562 extern tree find_data_references_in_bb (class loop *, basic_block,
563 vec<data_reference_p> *);
564 extern unsigned int dr_alignment (innermost_loop_behavior *);
565 extern tree get_base_for_alignment (tree, unsigned int *);
566
567 /* Return the alignment in bytes that DR is guaranteed to have at all
568 times. */
569
570 inline unsigned int
571 dr_alignment (data_reference *dr)
572 {
573 return dr_alignment (&DR_INNERMOST (dr));
574 }
575
576 extern bool dr_may_alias_p (const struct data_reference *,
577 const struct data_reference *, class loop *);
578 extern bool dr_equal_offsets_p (struct data_reference *,
579 struct data_reference *);
580
581 extern opt_result runtime_alias_check_p (ddr_p, class loop *, bool);
582 extern int data_ref_compare_tree (tree, tree);
583 extern void prune_runtime_alias_test_list (vec<dr_with_seg_len_pair_t> *,
584 poly_uint64);
585 extern void create_runtime_alias_checks (class loop *,
586 const vec<dr_with_seg_len_pair_t> *,
587 tree*);
588 extern tree dr_direction_indicator (struct data_reference *);
589 extern tree dr_zero_step_indicator (struct data_reference *);
590 extern bool dr_known_forward_stride_p (struct data_reference *);
591
592 /* Return true when the base objects of data references A and B are
593 the same memory object. */
594
595 inline bool
596 same_data_refs_base_objects (data_reference_p a, data_reference_p b)
597 {
598 return DR_NUM_DIMENSIONS (a) == DR_NUM_DIMENSIONS (b)
599 && operand_equal_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b), 0);
600 }
601
602 /* Return true when the data references A and B are accessing the same
603 memory object with the same access functions. Optionally skip the
604 last OFFSET dimensions in the data reference. */
605
606 inline bool
607 same_data_refs (data_reference_p a, data_reference_p b, int offset = 0)
608 {
609 unsigned int i;
610
611 /* The references are exactly the same. */
612 if (operand_equal_p (DR_REF (a), DR_REF (b), 0))
613 return true;
614
615 if (!same_data_refs_base_objects (a, b))
616 return false;
617
618 for (i = offset; i < DR_NUM_DIMENSIONS (a); i++)
619 if (!eq_evolutions_p (DR_ACCESS_FN (a, i), DR_ACCESS_FN (b, i)))
620 return false;
621
622 return true;
623 }
624
625 /* Returns true when all the dependences are computable. */
626
627 inline bool
628 known_dependences_p (vec<ddr_p> dependence_relations)
629 {
630 ddr_p ddr;
631 unsigned int i;
632
633 FOR_EACH_VEC_ELT (dependence_relations, i, ddr)
634 if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
635 return false;
636
637 return true;
638 }
639
640 /* Returns the dependence level for a vector DIST of size LENGTH.
641 LEVEL = 0 means a lexicographic dependence, i.e. a dependence due
642 to the sequence of statements, not carried by any loop. */
643
644 inline unsigned
645 dependence_level (lambda_vector dist_vect, int length)
646 {
647 int i;
648
649 for (i = 0; i < length; i++)
650 if (dist_vect[i] != 0)
651 return i + 1;
652
653 return 0;
654 }
655
656 /* Return the dependence level for the DDR relation. */
657
658 inline unsigned
659 ddr_dependence_level (ddr_p ddr)
660 {
661 unsigned vector;
662 unsigned level = 0;
663
664 if (DDR_DIST_VECTS (ddr).exists ())
665 level = dependence_level (DDR_DIST_VECT (ddr, 0), DDR_NB_LOOPS (ddr));
666
667 for (vector = 1; vector < DDR_NUM_DIST_VECTS (ddr); vector++)
668 level = MIN (level, dependence_level (DDR_DIST_VECT (ddr, vector),
669 DDR_NB_LOOPS (ddr)));
670 return level;
671 }
672
673 /* Return the index of the variable VAR in the LOOP_NEST array. */
674
675 inline int
676 index_in_loop_nest (int var, const vec<loop_p> &loop_nest)
677 {
678 class loop *loopi;
679 int var_index;
680
681 for (var_index = 0; loop_nest.iterate (var_index, &loopi); var_index++)
682 if (loopi->num == var)
683 return var_index;
684
685 gcc_unreachable ();
686 }
687
688 /* Returns true when the data reference DR the form "A[i] = ..."
689 with a stride equal to its unit type size. */
690
691 inline bool
692 adjacent_dr_p (struct data_reference *dr)
693 {
694 /* If this is a bitfield store bail out. */
695 if (TREE_CODE (DR_REF (dr)) == COMPONENT_REF
696 && DECL_BIT_FIELD (TREE_OPERAND (DR_REF (dr), 1)))
697 return false;
698
699 if (!DR_STEP (dr)
700 || TREE_CODE (DR_STEP (dr)) != INTEGER_CST)
701 return false;
702
703 return tree_int_cst_equal (fold_unary (ABS_EXPR, TREE_TYPE (DR_STEP (dr)),
704 DR_STEP (dr)),
705 TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr))));
706 }
707
708 void split_constant_offset (tree , tree *, tree *);
709
710 /* Compute the greatest common divisor of a VECTOR of SIZE numbers. */
711
712 inline lambda_int
713 lambda_vector_gcd (lambda_vector vector, int size)
714 {
715 int i;
716 lambda_int gcd1 = 0;
717
718 if (size > 0)
719 {
720 gcd1 = vector[0];
721 for (i = 1; i < size; i++)
722 gcd1 = gcd (gcd1, vector[i]);
723 }
724 return gcd1;
725 }
726
727 /* Allocate a new vector of given SIZE. */
728
729 inline lambda_vector
730 lambda_vector_new (int size)
731 {
732 /* ??? We shouldn't abuse the GC allocator here. */
733 return ggc_cleared_vec_alloc<lambda_int> (size);
734 }
735
736 /* Clear out vector VEC1 of length SIZE. */
737
738 inline void
739 lambda_vector_clear (lambda_vector vec1, int size)
740 {
741 memset (vec1, 0, size * sizeof (*vec1));
742 }
743
744 /* Returns true when the vector V is lexicographically positive, in
745 other words, when the first nonzero element is positive. */
746
747 inline bool
748 lambda_vector_lexico_pos (lambda_vector v,
749 unsigned n)
750 {
751 unsigned i;
752 for (i = 0; i < n; i++)
753 {
754 if (v[i] == 0)
755 continue;
756 if (v[i] < 0)
757 return false;
758 if (v[i] > 0)
759 return true;
760 }
761 return true;
762 }
763
764 /* Return true if vector VEC1 of length SIZE is the zero vector. */
765
766 inline bool
767 lambda_vector_zerop (lambda_vector vec1, int size)
768 {
769 int i;
770 for (i = 0; i < size; i++)
771 if (vec1[i] != 0)
772 return false;
773 return true;
774 }
775
776 /* Allocate a matrix of M rows x N cols. */
777
778 inline lambda_matrix
779 lambda_matrix_new (int m, int n, struct obstack *lambda_obstack)
780 {
781 lambda_matrix mat;
782 int i;
783
784 mat = XOBNEWVEC (lambda_obstack, lambda_vector, m);
785
786 for (i = 0; i < m; i++)
787 mat[i] = XOBNEWVEC (lambda_obstack, lambda_int, n);
788
789 return mat;
790 }
791
792 #endif /* GCC_TREE_DATA_REF_H */