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4ee9c684 | 1 | /* Dependency analysis |
2 | Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc. | |
3 | Contributed by Paul Brook <paul@nowt.org> | |
4 | ||
5 | This file is part of GNU G95. | |
6 | ||
7 | GNU G95 is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2, or (at your option) | |
10 | any later version. | |
11 | ||
12 | GNU G95 is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GNU G95; see the file COPYING. If not, write to | |
19 | the Free Software Foundation, 59 Temple Place - Suite 330, | |
20 | Boston, MA 02111-1307, USA. */ | |
21 | ||
22 | /* dependency.c -- Expression dependency analysis code. */ | |
23 | /* There's probably quite a bit of duplication in this file. We currently | |
24 | have different dependency checking functions for different types | |
25 | if dependencies. Ideally these would probably be merged. */ | |
26 | ||
27 | ||
28 | #include "config.h" | |
29 | #include "gfortran.h" | |
30 | #include "dependency.h" | |
31 | #include <assert.h> | |
32 | ||
33 | /* static declarations */ | |
34 | /* Enums */ | |
35 | enum range {LHS, RHS, MID}; | |
36 | ||
37 | /* Dependency types. These must be in reverse order of priority. */ | |
38 | typedef enum | |
39 | { | |
40 | GFC_DEP_ERROR, | |
41 | GFC_DEP_EQUAL, /* Identical Ranges. */ | |
42 | GFC_DEP_FORWARD, /* eg. a(1:3), a(2:4). */ | |
43 | GFC_DEP_OVERLAP, /* May overlap in some other way. */ | |
44 | GFC_DEP_NODEP /* Distinct ranges. */ | |
45 | } | |
46 | gfc_dependency; | |
47 | ||
48 | /* Macros */ | |
49 | #define IS_ARRAY_EXPLICIT(as) ((as->type == AS_EXPLICIT ? 1 : 0)) | |
50 | ||
51 | ||
52 | /* Returns 1 if the expr is an integer constant value 1, 0 if it is not or | |
53 | def if the value could not be determined. */ | |
54 | ||
55 | int | |
56 | gfc_expr_is_one (gfc_expr * expr, int def) | |
57 | { | |
58 | assert (expr != NULL); | |
59 | ||
60 | if (expr->expr_type != EXPR_CONSTANT) | |
61 | return def; | |
62 | ||
63 | if (expr->ts.type != BT_INTEGER) | |
64 | return def; | |
65 | ||
66 | return mpz_cmp_si (expr->value.integer, 1) == 0; | |
67 | } | |
68 | ||
69 | ||
70 | /* Compare two values. Returns 0 if e1 == e2, -1 if e1 < e2, +1 if e1 > e2, | |
71 | and -2 if the relationship could not be determined. */ | |
72 | ||
73 | int | |
74 | gfc_dep_compare_expr (gfc_expr * e1, gfc_expr * e2) | |
75 | { | |
76 | int i; | |
77 | ||
78 | if (e1->expr_type != e2->expr_type) | |
79 | return -2; | |
80 | ||
81 | switch (e1->expr_type) | |
82 | { | |
83 | case EXPR_CONSTANT: | |
84 | if (e1->ts.type != BT_INTEGER || e2->ts.type != BT_INTEGER) | |
85 | return -2; | |
86 | ||
87 | i = mpz_cmp (e1->value.integer, e2->value.integer); | |
88 | if (i == 0) | |
89 | return 0; | |
90 | else if (i < 0) | |
91 | return -1; | |
92 | return 1; | |
93 | ||
94 | case EXPR_VARIABLE: | |
95 | if (e1->ref || e2->ref) | |
96 | return -2; | |
97 | if (e1->symtree->n.sym == e2->symtree->n.sym) | |
98 | return 0; | |
99 | return -2; | |
100 | ||
101 | default: | |
102 | return -2; | |
103 | } | |
104 | } | |
105 | ||
106 | ||
107 | /* Returns 1 if the two ranges are the same, 0 if they are not, and def | |
108 | if the results are indeterminate. N is the dimension to compare. */ | |
109 | ||
110 | int | |
111 | gfc_is_same_range (gfc_array_ref * ar1, gfc_array_ref * ar2, int n, int def) | |
112 | { | |
113 | gfc_expr *e1; | |
114 | gfc_expr *e2; | |
115 | int i; | |
116 | ||
117 | /* TODO: More sophisticated range comparison. */ | |
118 | assert (ar1 && ar2); | |
119 | ||
120 | assert (ar1->dimen_type[n] == ar2->dimen_type[n]); | |
121 | ||
122 | e1 = ar1->stride[n]; | |
123 | e2 = ar2->stride[n]; | |
124 | /* Check for mismatching strides. A NULL stride means a stride of 1. */ | |
125 | if (e1 && !e2) | |
126 | { | |
127 | i = gfc_expr_is_one (e1, -1); | |
128 | if (i == -1) | |
129 | return def; | |
130 | else if (i == 0) | |
131 | return 0; | |
132 | } | |
133 | else if (e2 && !e1) | |
134 | { | |
135 | i = gfc_expr_is_one (e2, -1); | |
136 | if (i == -1) | |
137 | return def; | |
138 | else if (i == 0) | |
139 | return 0; | |
140 | } | |
141 | else if (e1 && e2) | |
142 | { | |
143 | i = gfc_dep_compare_expr (e1, e2); | |
144 | if (i == -2) | |
145 | return def; | |
146 | else if (i != 0) | |
147 | return 0; | |
148 | } | |
149 | /* The strides match. */ | |
150 | ||
151 | /* Check the range start. */ | |
152 | e1 = ar1->start[n]; | |
153 | e2 = ar2->start[n]; | |
154 | ||
155 | if (!(e1 || e2)) | |
156 | return 1; | |
157 | ||
158 | /* Use the bound of the array if no bound is specified. */ | |
159 | if (ar1->as && !e1) | |
160 | e1 = ar1->as->lower[n]; | |
161 | ||
162 | if (ar2->as && !e2) | |
163 | e2 = ar2->as->upper[n]; | |
164 | ||
165 | /* Check we have values for both. */ | |
166 | if (!(e1 && e2)) | |
167 | return def; | |
168 | ||
169 | i = gfc_dep_compare_expr (e1, e2); | |
170 | ||
171 | if (i == -2) | |
172 | return def; | |
173 | else if (i == 0) | |
174 | return 1; | |
175 | return 0; | |
176 | } | |
177 | ||
178 | ||
179 | /* Dependency checking for direct function return by reference. | |
180 | Returns true if the arguments of the function depend on the | |
181 | destination. This is considerably less conservative than other | |
182 | dependencies because many function arguments will already be | |
183 | copied into a temporary. */ | |
184 | ||
185 | int | |
186 | gfc_check_fncall_dependency (gfc_expr * dest, gfc_expr * fncall) | |
187 | { | |
188 | gfc_actual_arglist *actual; | |
189 | gfc_ref *ref; | |
190 | gfc_expr *expr; | |
191 | int n; | |
192 | ||
193 | assert (dest->expr_type == EXPR_VARIABLE | |
194 | && fncall->expr_type == EXPR_FUNCTION); | |
195 | assert (fncall->rank > 0); | |
196 | ||
197 | for (actual = fncall->value.function.actual; actual; actual = actual->next) | |
198 | { | |
199 | expr = actual->expr; | |
200 | ||
201 | /* Skip args which are not present. */ | |
202 | if (!expr) | |
203 | continue; | |
204 | ||
205 | /* Non-variable expressions will be allocated temporaries anyway. */ | |
206 | switch (expr->expr_type) | |
207 | { | |
208 | case EXPR_VARIABLE: | |
209 | if (expr->rank > 1) | |
210 | { | |
211 | /* This is an array section. */ | |
212 | for (ref = expr->ref; ref; ref = ref->next) | |
213 | { | |
214 | if (ref->type == REF_ARRAY && ref->u.ar.type != AR_ELEMENT) | |
215 | break; | |
216 | } | |
217 | assert (ref); | |
218 | /* AR_FULL can't contain vector subscripts. */ | |
219 | if (ref->u.ar.type == AR_SECTION) | |
220 | { | |
221 | for (n = 0; n < ref->u.ar.dimen; n++) | |
222 | { | |
223 | if (ref->u.ar.dimen_type[n] == DIMEN_VECTOR) | |
224 | break; | |
225 | } | |
226 | /* Vector subscript array sections will be copied to a | |
227 | temporary. */ | |
228 | if (n != ref->u.ar.dimen) | |
229 | continue; | |
230 | } | |
231 | } | |
232 | ||
233 | if (gfc_check_dependency (dest, actual->expr, NULL, 0)) | |
234 | return 1; | |
235 | break; | |
236 | ||
237 | case EXPR_ARRAY: | |
238 | if (gfc_check_dependency (dest, expr, NULL, 0)) | |
239 | return 1; | |
240 | break; | |
241 | ||
242 | default: | |
243 | break; | |
244 | } | |
245 | } | |
246 | ||
247 | return 0; | |
248 | } | |
249 | ||
250 | ||
251 | /* Return true if the statement body redefines the condition. Returns | |
252 | true if expr2 depends on expr1. expr1 should be a single term | |
253 | suitable for the lhs of an assignment. The symbols listed in VARS | |
254 | must be considered to have all possible values. All other scalar | |
255 | variables may be considered constant. Used for forall and where | |
256 | statements. Also used with functions returning arrays without a | |
257 | temporary. */ | |
258 | ||
259 | int | |
260 | gfc_check_dependency (gfc_expr * expr1, gfc_expr * expr2, gfc_expr ** vars, | |
261 | int nvars) | |
262 | { | |
263 | gfc_ref *ref; | |
264 | int n; | |
265 | gfc_actual_arglist *actual; | |
266 | ||
267 | assert (expr1->expr_type == EXPR_VARIABLE); | |
268 | ||
269 | /* TODO: -fassume-no-pointer-aliasing */ | |
270 | if (expr1->symtree->n.sym->attr.pointer) | |
271 | return 1; | |
272 | for (ref = expr1->ref; ref; ref = ref->next) | |
273 | { | |
274 | if (ref->type == REF_COMPONENT && ref->u.c.component->pointer) | |
275 | return 1; | |
276 | } | |
277 | ||
278 | switch (expr2->expr_type) | |
279 | { | |
280 | case EXPR_OP: | |
281 | n = gfc_check_dependency (expr1, expr2->op1, vars, nvars); | |
282 | if (n) | |
283 | return n; | |
284 | if (expr2->op2) | |
285 | return gfc_check_dependency (expr1, expr2->op2, vars, nvars); | |
286 | return 0; | |
287 | ||
288 | case EXPR_VARIABLE: | |
289 | if (expr2->symtree->n.sym->attr.pointer) | |
290 | return 1; | |
291 | ||
292 | for (ref = expr2->ref; ref; ref = ref->next) | |
293 | { | |
294 | if (ref->type == REF_COMPONENT && ref->u.c.component->pointer) | |
295 | return 1; | |
296 | } | |
297 | ||
298 | if (expr1->symtree->n.sym != expr2->symtree->n.sym) | |
299 | return 0; | |
300 | ||
301 | for (ref = expr2->ref; ref; ref = ref->next) | |
302 | { | |
303 | /* Identical ranges return 0, overlapping ranges return 1. */ | |
304 | if (ref->type == REF_ARRAY) | |
305 | return 1; | |
306 | } | |
307 | return 1; | |
308 | ||
309 | case EXPR_FUNCTION: | |
310 | /* Remember possible differences betweeen elemental and | |
311 | transformational functions. All functions inside a FORALL | |
312 | will be pure. */ | |
313 | for (actual = expr2->value.function.actual; | |
314 | actual; actual = actual->next) | |
315 | { | |
316 | if (!actual->expr) | |
317 | continue; | |
318 | n = gfc_check_dependency (expr1, actual->expr, vars, nvars); | |
319 | if (n) | |
320 | return n; | |
321 | } | |
322 | return 0; | |
323 | ||
324 | case EXPR_CONSTANT: | |
325 | return 0; | |
326 | ||
327 | case EXPR_ARRAY: | |
328 | /* Probably ok in the majority of (constant) cases. */ | |
329 | return 1; | |
330 | ||
331 | default: | |
332 | return 1; | |
333 | } | |
334 | } | |
335 | ||
336 | ||
337 | /* Calculates size of the array reference using lower bound, upper bound | |
338 | and stride. */ | |
339 | ||
340 | static void | |
341 | get_no_of_elements(mpz_t ele, gfc_expr * u1, gfc_expr * l1, gfc_expr * s1) | |
342 | { | |
343 | /* nNoOfEle = (u1-l1)/s1 */ | |
344 | ||
345 | mpz_sub (ele, u1->value.integer, l1->value.integer); | |
346 | ||
347 | if (s1 != NULL) | |
348 | mpz_tdiv_q (ele, ele, s1->value.integer); | |
349 | } | |
350 | ||
351 | ||
352 | /* Returns if the ranges ((0..Y), (X1..X2)) overlap. */ | |
353 | ||
354 | static gfc_dependency | |
355 | get_deps (mpz_t x1, mpz_t x2, mpz_t y) | |
356 | { | |
357 | int start; | |
358 | int end; | |
359 | ||
360 | start = mpz_cmp_ui (x1, 0); | |
361 | end = mpz_cmp (x2, y); | |
362 | ||
363 | /* Both ranges the same. */ | |
364 | if (start == 0 && end == 0) | |
365 | return GFC_DEP_EQUAL; | |
366 | ||
367 | /* Distinct ranges. */ | |
368 | if ((start < 0 && mpz_cmp_ui (x2, 0) < 0) | |
369 | || (mpz_cmp (x1, y) > 0 && end > 0)) | |
370 | return GFC_DEP_NODEP; | |
371 | ||
372 | /* Overlapping, but with corresponding elements of the second range | |
373 | greater than the first. */ | |
374 | if (start > 0 && end > 0) | |
375 | return GFC_DEP_FORWARD; | |
376 | ||
377 | /* Overlapping in some other way. */ | |
378 | return GFC_DEP_OVERLAP; | |
379 | } | |
380 | ||
381 | ||
382 | /* Transforms a sections l and r such that | |
383 | (l_start:l_end:l_stride) -> (0:no_of_elements) | |
384 | (r_start:r_end:r_stride) -> (X1:X2) | |
385 | Where r_end is implicit as both sections must have the same number of | |
386 | elelments. | |
387 | Returns 0 on success, 1 of the transformation failed. */ | |
388 | /* TODO: Should this be (0:no_of_elements-1) */ | |
389 | ||
390 | static int | |
391 | transform_sections (mpz_t X1, mpz_t X2, mpz_t no_of_elements, | |
392 | gfc_expr * l_start, gfc_expr * l_end, gfc_expr * l_stride, | |
393 | gfc_expr * r_start, gfc_expr * r_stride) | |
394 | { | |
395 | if (NULL == l_start || NULL == l_end || NULL == r_start) | |
396 | return 1; | |
397 | ||
398 | /* TODO : Currently we check the dependency only when start, end and stride | |
399 | are constant. We could also check for equal (variable) values, and | |
400 | common subexpressions, eg. x vs. x+1. */ | |
401 | ||
402 | if (l_end->expr_type != EXPR_CONSTANT | |
403 | || l_start->expr_type != EXPR_CONSTANT | |
404 | || r_start->expr_type != EXPR_CONSTANT | |
405 | || ((NULL != l_stride) && (l_stride->expr_type != EXPR_CONSTANT)) | |
406 | || ((NULL != r_stride) && (r_stride->expr_type != EXPR_CONSTANT))) | |
407 | { | |
408 | return 1; | |
409 | } | |
410 | ||
411 | ||
412 | get_no_of_elements (no_of_elements, l_end, l_start, l_stride); | |
413 | ||
414 | mpz_sub (X1, r_start->value.integer, l_start->value.integer); | |
415 | if (l_stride != NULL) | |
416 | mpz_cdiv_q (X1, X1, l_stride->value.integer); | |
417 | ||
418 | if (r_stride == NULL) | |
419 | mpz_set (X2, no_of_elements); | |
420 | else | |
421 | mpz_mul (X2, no_of_elements, r_stride->value.integer); | |
422 | ||
423 | if (l_stride != NULL) | |
424 | mpz_cdiv_q (X2, X2, r_stride->value.integer); | |
425 | mpz_add (X2, X2, X1); | |
426 | ||
427 | return 0; | |
428 | } | |
429 | ||
430 | ||
431 | /* Determines overlapping for two array sections. */ | |
432 | ||
433 | static gfc_dependency | |
434 | gfc_check_section_vs_section (gfc_ref * lref, gfc_ref * rref, int n) | |
435 | { | |
436 | gfc_expr *l_start; | |
437 | gfc_expr *l_end; | |
438 | gfc_expr *l_stride; | |
439 | ||
440 | gfc_expr *r_start; | |
441 | gfc_expr *r_stride; | |
442 | ||
443 | gfc_array_ref l_ar; | |
444 | gfc_array_ref r_ar; | |
445 | ||
446 | mpz_t no_of_elements; | |
447 | mpz_t X1, X2; | |
448 | gfc_dependency dep; | |
449 | ||
450 | l_ar = lref->u.ar; | |
451 | r_ar = rref->u.ar; | |
452 | ||
453 | l_start = l_ar.start[n]; | |
454 | l_end = l_ar.end[n]; | |
455 | l_stride = l_ar.stride[n]; | |
456 | r_start = r_ar.start[n]; | |
457 | r_stride = r_ar.stride[n]; | |
458 | ||
459 | /* if l_start is NULL take it from array specifier */ | |
460 | if (NULL == l_start && IS_ARRAY_EXPLICIT(l_ar.as)) | |
461 | l_start = l_ar.as->lower[n]; | |
462 | ||
463 | /* if l_end is NULL take it from array specifier */ | |
464 | if (NULL == l_end && IS_ARRAY_EXPLICIT(l_ar.as)) | |
465 | l_end = l_ar.as->upper[n]; | |
466 | ||
467 | /* if r_start is NULL take it from array specifier */ | |
468 | if (NULL == r_start && IS_ARRAY_EXPLICIT(r_ar.as)) | |
469 | r_start = r_ar.as->lower[n]; | |
470 | ||
471 | mpz_init (X1); | |
472 | mpz_init (X2); | |
473 | mpz_init (no_of_elements); | |
474 | ||
475 | if (transform_sections (X1, X2, no_of_elements, | |
476 | l_start, l_end, l_stride, | |
477 | r_start, r_stride)) | |
478 | dep = GFC_DEP_OVERLAP; | |
479 | else | |
480 | dep = get_deps (X1, X2, no_of_elements); | |
481 | ||
482 | mpz_clear (no_of_elements); | |
483 | mpz_clear (X1); | |
484 | mpz_clear (X2); | |
485 | return dep; | |
486 | } | |
487 | ||
488 | ||
489 | /* Checks if the expr chk is inside the range left-right. | |
490 | Returns GFC_DEP_NODEP if chk is outside the range, | |
491 | GFC_DEP_OVERLAP otherwise. | |
492 | Assumes left<=right. */ | |
493 | ||
494 | static gfc_dependency | |
495 | gfc_is_inside_range (gfc_expr * chk, gfc_expr * left, gfc_expr * right) | |
496 | { | |
497 | int l; | |
498 | int r; | |
499 | int s; | |
500 | ||
501 | s = gfc_dep_compare_expr (left, right); | |
502 | if (s == -2) | |
503 | return GFC_DEP_OVERLAP; | |
504 | ||
505 | l = gfc_dep_compare_expr (chk, left); | |
506 | r = gfc_dep_compare_expr (chk, right); | |
507 | ||
508 | /* Check for indeterminate relationships. */ | |
509 | if (l == -2 || r == -2 || s == -2) | |
510 | return GFC_DEP_OVERLAP; | |
511 | ||
512 | if (s == 1) | |
513 | { | |
514 | /* When left>right we want to check for right <= chk <= left. */ | |
515 | if (l <= 0 || r >= 0) | |
516 | return GFC_DEP_OVERLAP; | |
517 | } | |
518 | else | |
519 | { | |
520 | /* Otherwise check for left <= chk <= right. */ | |
521 | if (l >= 0 || r <= 0) | |
522 | return GFC_DEP_OVERLAP; | |
523 | } | |
524 | ||
525 | return GFC_DEP_NODEP; | |
526 | } | |
527 | ||
528 | ||
529 | /* Determines overlapping for a single element and a section. */ | |
530 | ||
531 | static gfc_dependency | |
532 | gfc_check_element_vs_section( gfc_ref * lref, gfc_ref * rref, int n) | |
533 | { | |
534 | gfc_array_ref l_ar; | |
535 | gfc_array_ref r_ar; | |
536 | gfc_expr *l_start; | |
537 | gfc_expr *r_start; | |
538 | gfc_expr *r_end; | |
539 | ||
540 | l_ar = lref->u.ar; | |
541 | r_ar = rref->u.ar; | |
542 | l_start = l_ar.start[n] ; | |
543 | r_start = r_ar.start[n] ; | |
544 | r_end = r_ar.end[n] ; | |
545 | if (NULL == r_start && IS_ARRAY_EXPLICIT (r_ar.as)) | |
546 | r_start = r_ar.as->lower[n]; | |
547 | if (NULL == r_end && IS_ARRAY_EXPLICIT (r_ar.as)) | |
548 | r_end = r_ar.as->upper[n]; | |
549 | if (NULL == r_start || NULL == r_end || l_start == NULL) | |
550 | return GFC_DEP_OVERLAP; | |
551 | ||
552 | return gfc_is_inside_range (l_start, r_end, r_start); | |
553 | } | |
554 | ||
555 | ||
556 | /* Determines overlapping for two single element array references. */ | |
557 | ||
558 | static gfc_dependency | |
559 | gfc_check_element_vs_element (gfc_ref * lref, gfc_ref * rref, int n) | |
560 | { | |
561 | gfc_array_ref l_ar; | |
562 | gfc_array_ref r_ar; | |
563 | gfc_expr *l_start; | |
564 | gfc_expr *r_start; | |
565 | gfc_dependency nIsDep; | |
566 | ||
567 | if (lref->type == REF_ARRAY && rref->type == REF_ARRAY) | |
568 | { | |
569 | l_ar = lref->u.ar; | |
570 | r_ar = rref->u.ar; | |
571 | l_start = l_ar.start[n] ; | |
572 | r_start = r_ar.start[n] ; | |
573 | if (gfc_dep_compare_expr (r_start, l_start) == 0) | |
574 | nIsDep = GFC_DEP_EQUAL; | |
575 | else | |
576 | nIsDep = GFC_DEP_NODEP; | |
577 | } | |
578 | else | |
579 | nIsDep = GFC_DEP_NODEP; | |
580 | ||
581 | return nIsDep; | |
582 | } | |
583 | ||
584 | ||
585 | /* Finds if two array references are overlapping or not. | |
586 | Return value | |
587 | 1 : array references are overlapping. | |
588 | 0 : array references are not overlapping. */ | |
589 | ||
590 | int | |
591 | gfc_dep_resolver (gfc_ref * lref, gfc_ref * rref) | |
592 | { | |
593 | int n; | |
594 | gfc_dependency fin_dep; | |
595 | gfc_dependency this_dep; | |
596 | ||
597 | ||
598 | fin_dep = GFC_DEP_ERROR; | |
599 | /* Dependencies due to pointers should already have been identified. | |
600 | We only need to check for overlapping array references. */ | |
601 | ||
602 | while (lref && rref) | |
603 | { | |
604 | /* We're resolving from the same base symbol, so both refs should be | |
605 | the same type. We traverse the reference chain intil we find ranges | |
606 | that are not equal. */ | |
607 | assert (lref->type == rref->type); | |
608 | switch (lref->type) | |
609 | { | |
610 | case REF_COMPONENT: | |
611 | /* The two ranges can't overlap if they are from different | |
612 | components. */ | |
613 | if (lref->u.c.component != rref->u.c.component) | |
614 | return 0; | |
615 | break; | |
616 | ||
617 | case REF_SUBSTRING: | |
618 | /* Substring overlaps are handled by the string assignment code. */ | |
619 | return 0; | |
620 | ||
621 | case REF_ARRAY: | |
622 | ||
623 | for (n=0; n < lref->u.ar.dimen; n++) | |
624 | { | |
625 | /* Assume dependency when either of array reference is vector | |
626 | subscript. */ | |
627 | if (lref->u.ar.dimen_type[n] == DIMEN_VECTOR | |
628 | || rref->u.ar.dimen_type[n] == DIMEN_VECTOR) | |
629 | return 1; | |
630 | if (lref->u.ar.dimen_type[n] == DIMEN_RANGE | |
631 | && rref->u.ar.dimen_type[n] == DIMEN_RANGE) | |
632 | this_dep = gfc_check_section_vs_section (lref, rref, n); | |
633 | else if (lref->u.ar.dimen_type[n] == DIMEN_ELEMENT | |
634 | && rref->u.ar.dimen_type[n] == DIMEN_RANGE) | |
635 | this_dep = gfc_check_element_vs_section (lref, rref, n); | |
636 | else if (rref->u.ar.dimen_type[n] == DIMEN_ELEMENT | |
637 | && lref->u.ar.dimen_type[n] == DIMEN_RANGE) | |
638 | this_dep = gfc_check_element_vs_section (rref, lref, n); | |
639 | else | |
640 | { | |
641 | assert (rref->u.ar.dimen_type[n] == DIMEN_ELEMENT | |
642 | && lref->u.ar.dimen_type[n] == DIMEN_ELEMENT); | |
643 | this_dep = gfc_check_element_vs_element (rref, lref, n); | |
644 | } | |
645 | ||
646 | /* If any dimension doesn't overlap, we have no dependency. */ | |
647 | if (this_dep == GFC_DEP_NODEP) | |
648 | return 0; | |
649 | ||
650 | /* Overlap codes are in order of priority. We only need to | |
651 | know the worst one.*/ | |
652 | if (this_dep > fin_dep) | |
653 | fin_dep = this_dep; | |
654 | } | |
655 | /* Exactly matching and forward overlapping ranges don't cause a | |
656 | dependency. */ | |
657 | if (fin_dep < GFC_DEP_OVERLAP) | |
658 | return 0; | |
659 | ||
660 | /* Keep checking. We only have a dependency if | |
661 | subsequent references also overlap. */ | |
662 | break; | |
663 | ||
664 | default: | |
665 | abort(); | |
666 | } | |
667 | lref = lref->next; | |
668 | rref = rref->next; | |
669 | } | |
670 | ||
671 | /* If we haven't seen any array refs then something went wrong. */ | |
672 | assert (fin_dep != GFC_DEP_ERROR); | |
673 | ||
674 | if (fin_dep < GFC_DEP_OVERLAP) | |
675 | return 0; | |
676 | else | |
677 | return 1; | |
678 | } | |
679 |