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4ee9c684 | 1 | /* Dependency analysis |
7b3423b9 | 2 | Copyright (C) 2000, 2001, 2002, 2005 Free Software Foundation, Inc. |
4ee9c684 | 3 | Contributed by Paul Brook <paul@nowt.org> |
4 | ||
c84b470d | 5 | This file is part of GCC. |
4ee9c684 | 6 | |
c84b470d | 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 2, or (at your option) any later | |
10 | version. | |
4ee9c684 | 11 | |
c84b470d | 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. | |
4ee9c684 | 16 | |
17 | You should have received a copy of the GNU General Public License | |
c84b470d | 18 | along with GCC; see the file COPYING. If not, write to the Free |
30d4ffea | 19 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
20 | 02110-1301, USA. */ | |
4ee9c684 | 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" | |
4ee9c684 | 31 | |
32 | /* static declarations */ | |
33 | /* Enums */ | |
34 | enum range {LHS, RHS, MID}; | |
35 | ||
36 | /* Dependency types. These must be in reverse order of priority. */ | |
37 | typedef enum | |
38 | { | |
39 | GFC_DEP_ERROR, | |
40 | GFC_DEP_EQUAL, /* Identical Ranges. */ | |
41 | GFC_DEP_FORWARD, /* eg. a(1:3), a(2:4). */ | |
42 | GFC_DEP_OVERLAP, /* May overlap in some other way. */ | |
43 | GFC_DEP_NODEP /* Distinct ranges. */ | |
44 | } | |
45 | gfc_dependency; | |
46 | ||
47 | /* Macros */ | |
48 | #define IS_ARRAY_EXPLICIT(as) ((as->type == AS_EXPLICIT ? 1 : 0)) | |
49 | ||
50 | ||
51 | /* Returns 1 if the expr is an integer constant value 1, 0 if it is not or | |
52 | def if the value could not be determined. */ | |
53 | ||
54 | int | |
55 | gfc_expr_is_one (gfc_expr * expr, int def) | |
56 | { | |
22d678e8 | 57 | gcc_assert (expr != NULL); |
4ee9c684 | 58 | |
59 | if (expr->expr_type != EXPR_CONSTANT) | |
60 | return def; | |
61 | ||
62 | if (expr->ts.type != BT_INTEGER) | |
63 | return def; | |
64 | ||
65 | return mpz_cmp_si (expr->value.integer, 1) == 0; | |
66 | } | |
67 | ||
68 | ||
69 | /* Compare two values. Returns 0 if e1 == e2, -1 if e1 < e2, +1 if e1 > e2, | |
70 | and -2 if the relationship could not be determined. */ | |
71 | ||
72 | int | |
73 | gfc_dep_compare_expr (gfc_expr * e1, gfc_expr * e2) | |
74 | { | |
75 | int i; | |
76 | ||
77 | if (e1->expr_type != e2->expr_type) | |
78 | return -2; | |
79 | ||
80 | switch (e1->expr_type) | |
81 | { | |
82 | case EXPR_CONSTANT: | |
83 | if (e1->ts.type != BT_INTEGER || e2->ts.type != BT_INTEGER) | |
84 | return -2; | |
85 | ||
86 | i = mpz_cmp (e1->value.integer, e2->value.integer); | |
87 | if (i == 0) | |
88 | return 0; | |
89 | else if (i < 0) | |
90 | return -1; | |
91 | return 1; | |
92 | ||
93 | case EXPR_VARIABLE: | |
94 | if (e1->ref || e2->ref) | |
95 | return -2; | |
96 | if (e1->symtree->n.sym == e2->symtree->n.sym) | |
97 | return 0; | |
98 | return -2; | |
99 | ||
100 | default: | |
101 | return -2; | |
102 | } | |
103 | } | |
104 | ||
105 | ||
106 | /* Returns 1 if the two ranges are the same, 0 if they are not, and def | |
107 | if the results are indeterminate. N is the dimension to compare. */ | |
108 | ||
109 | int | |
110 | gfc_is_same_range (gfc_array_ref * ar1, gfc_array_ref * ar2, int n, int def) | |
111 | { | |
112 | gfc_expr *e1; | |
113 | gfc_expr *e2; | |
114 | int i; | |
115 | ||
116 | /* TODO: More sophisticated range comparison. */ | |
22d678e8 | 117 | gcc_assert (ar1 && ar2); |
4ee9c684 | 118 | |
22d678e8 | 119 | gcc_assert (ar1->dimen_type[n] == ar2->dimen_type[n]); |
4ee9c684 | 120 | |
121 | e1 = ar1->stride[n]; | |
122 | e2 = ar2->stride[n]; | |
123 | /* Check for mismatching strides. A NULL stride means a stride of 1. */ | |
124 | if (e1 && !e2) | |
125 | { | |
126 | i = gfc_expr_is_one (e1, -1); | |
127 | if (i == -1) | |
128 | return def; | |
129 | else if (i == 0) | |
130 | return 0; | |
131 | } | |
132 | else if (e2 && !e1) | |
133 | { | |
134 | i = gfc_expr_is_one (e2, -1); | |
135 | if (i == -1) | |
136 | return def; | |
137 | else if (i == 0) | |
138 | return 0; | |
139 | } | |
140 | else if (e1 && e2) | |
141 | { | |
142 | i = gfc_dep_compare_expr (e1, e2); | |
143 | if (i == -2) | |
144 | return def; | |
145 | else if (i != 0) | |
146 | return 0; | |
147 | } | |
148 | /* The strides match. */ | |
149 | ||
150 | /* Check the range start. */ | |
151 | e1 = ar1->start[n]; | |
152 | e2 = ar2->start[n]; | |
153 | ||
154 | if (!(e1 || e2)) | |
155 | return 1; | |
156 | ||
157 | /* Use the bound of the array if no bound is specified. */ | |
158 | if (ar1->as && !e1) | |
159 | e1 = ar1->as->lower[n]; | |
160 | ||
161 | if (ar2->as && !e2) | |
162 | e2 = ar2->as->upper[n]; | |
163 | ||
164 | /* Check we have values for both. */ | |
165 | if (!(e1 && e2)) | |
166 | return def; | |
167 | ||
168 | i = gfc_dep_compare_expr (e1, e2); | |
169 | ||
170 | if (i == -2) | |
171 | return def; | |
172 | else if (i == 0) | |
173 | return 1; | |
174 | return 0; | |
175 | } | |
176 | ||
177 | ||
018ef8b8 | 178 | /* Some array-returning intrinsics can be implemented by reusing the |
22046c26 | 179 | data from one of the array arguments. For example, TRANSPOSE does |
018ef8b8 | 180 | not necessarily need to allocate new data: it can be implemented |
181 | by copying the original array's descriptor and simply swapping the | |
182 | two dimension specifications. | |
183 | ||
184 | If EXPR is a call to such an intrinsic, return the argument | |
185 | whose data can be reused, otherwise return NULL. */ | |
186 | ||
187 | gfc_expr * | |
188 | gfc_get_noncopying_intrinsic_argument (gfc_expr * expr) | |
189 | { | |
190 | if (expr->expr_type != EXPR_FUNCTION || !expr->value.function.isym) | |
191 | return NULL; | |
192 | ||
193 | switch (expr->value.function.isym->generic_id) | |
194 | { | |
195 | case GFC_ISYM_TRANSPOSE: | |
196 | return expr->value.function.actual->expr; | |
197 | ||
198 | default: | |
199 | return NULL; | |
200 | } | |
201 | } | |
202 | ||
203 | ||
c99d633f | 204 | /* Return true if the result of reference REF can only be constructed |
205 | using a temporary array. */ | |
206 | ||
207 | bool | |
208 | gfc_ref_needs_temporary_p (gfc_ref *ref) | |
209 | { | |
210 | int n; | |
211 | bool subarray_p; | |
212 | ||
213 | subarray_p = false; | |
214 | for (; ref; ref = ref->next) | |
215 | switch (ref->type) | |
216 | { | |
217 | case REF_ARRAY: | |
218 | /* Vector dimensions are generally not monotonic and must be | |
219 | handled using a temporary. */ | |
220 | if (ref->u.ar.type == AR_SECTION) | |
221 | for (n = 0; n < ref->u.ar.dimen; n++) | |
222 | if (ref->u.ar.dimen_type[n] == DIMEN_VECTOR) | |
223 | return true; | |
224 | ||
225 | subarray_p = true; | |
226 | break; | |
227 | ||
228 | case REF_SUBSTRING: | |
229 | /* Within an array reference, character substrings generally | |
230 | need a temporary. Character array strides are expressed as | |
231 | multiples of the element size (consistent with other array | |
232 | types), not in characters. */ | |
233 | return subarray_p; | |
234 | ||
235 | case REF_COMPONENT: | |
236 | break; | |
237 | } | |
238 | ||
239 | return false; | |
240 | } | |
241 | ||
242 | ||
018ef8b8 | 243 | /* Return true if array variable VAR could be passed to the same function |
244 | as argument EXPR without interfering with EXPR. INTENT is the intent | |
245 | of VAR. | |
246 | ||
247 | This is considerably less conservative than other dependencies | |
248 | because many function arguments will already be copied into a | |
249 | temporary. */ | |
250 | ||
251 | static int | |
252 | gfc_check_argument_var_dependency (gfc_expr * var, sym_intent intent, | |
253 | gfc_expr * expr) | |
254 | { | |
255 | gcc_assert (var->expr_type == EXPR_VARIABLE); | |
256 | gcc_assert (var->rank > 0); | |
257 | ||
258 | switch (expr->expr_type) | |
259 | { | |
260 | case EXPR_VARIABLE: | |
261 | return (gfc_ref_needs_temporary_p (expr->ref) | |
dded0b23 | 262 | || gfc_check_dependency (var, expr, 1)); |
018ef8b8 | 263 | |
264 | case EXPR_ARRAY: | |
dded0b23 | 265 | return gfc_check_dependency (var, expr, 1); |
018ef8b8 | 266 | |
267 | case EXPR_FUNCTION: | |
268 | if (intent != INTENT_IN && expr->inline_noncopying_intrinsic) | |
269 | { | |
270 | expr = gfc_get_noncopying_intrinsic_argument (expr); | |
271 | return gfc_check_argument_var_dependency (var, intent, expr); | |
272 | } | |
273 | return 0; | |
274 | ||
275 | default: | |
276 | return 0; | |
277 | } | |
278 | } | |
279 | ||
280 | ||
281 | /* Like gfc_check_argument_var_dependency, but extended to any | |
282 | array expression OTHER, not just variables. */ | |
283 | ||
284 | static int | |
285 | gfc_check_argument_dependency (gfc_expr * other, sym_intent intent, | |
286 | gfc_expr * expr) | |
287 | { | |
288 | switch (other->expr_type) | |
289 | { | |
290 | case EXPR_VARIABLE: | |
291 | return gfc_check_argument_var_dependency (other, intent, expr); | |
292 | ||
293 | case EXPR_FUNCTION: | |
294 | if (other->inline_noncopying_intrinsic) | |
295 | { | |
296 | other = gfc_get_noncopying_intrinsic_argument (other); | |
297 | return gfc_check_argument_dependency (other, INTENT_IN, expr); | |
298 | } | |
299 | return 0; | |
300 | ||
301 | default: | |
302 | return 0; | |
303 | } | |
304 | } | |
305 | ||
306 | ||
307 | /* Like gfc_check_argument_dependency, but check all the arguments in ACTUAL. | |
308 | FNSYM is the function being called, or NULL if not known. */ | |
4ee9c684 | 309 | |
310 | int | |
018ef8b8 | 311 | gfc_check_fncall_dependency (gfc_expr * other, sym_intent intent, |
312 | gfc_symbol * fnsym, gfc_actual_arglist * actual) | |
4ee9c684 | 313 | { |
018ef8b8 | 314 | gfc_formal_arglist *formal; |
4ee9c684 | 315 | gfc_expr *expr; |
4ee9c684 | 316 | |
018ef8b8 | 317 | formal = fnsym ? fnsym->formal : NULL; |
318 | for (; actual; actual = actual->next, formal = formal ? formal->next : NULL) | |
4ee9c684 | 319 | { |
320 | expr = actual->expr; | |
321 | ||
322 | /* Skip args which are not present. */ | |
323 | if (!expr) | |
324 | continue; | |
325 | ||
018ef8b8 | 326 | /* Skip intent(in) arguments if OTHER itself is intent(in). */ |
327 | if (formal | |
328 | && intent == INTENT_IN | |
329 | && formal->sym->attr.intent == INTENT_IN) | |
330 | continue; | |
331 | ||
332 | if (gfc_check_argument_dependency (other, intent, expr)) | |
333 | return 1; | |
4ee9c684 | 334 | } |
335 | ||
336 | return 0; | |
337 | } | |
338 | ||
339 | ||
340 | /* Return true if the statement body redefines the condition. Returns | |
341 | true if expr2 depends on expr1. expr1 should be a single term | |
dded0b23 | 342 | suitable for the lhs of an assignment. The IDENTICAL flag indicates |
343 | whether array references to the same symbol with identical range | |
344 | references count as a dependency or not. Used for forall and where | |
4ee9c684 | 345 | statements. Also used with functions returning arrays without a |
346 | temporary. */ | |
347 | ||
348 | int | |
dded0b23 | 349 | gfc_check_dependency (gfc_expr * expr1, gfc_expr * expr2, bool identical) |
4ee9c684 | 350 | { |
351 | gfc_ref *ref; | |
352 | int n; | |
353 | gfc_actual_arglist *actual; | |
354 | ||
22d678e8 | 355 | gcc_assert (expr1->expr_type == EXPR_VARIABLE); |
4ee9c684 | 356 | |
357 | /* TODO: -fassume-no-pointer-aliasing */ | |
358 | if (expr1->symtree->n.sym->attr.pointer) | |
359 | return 1; | |
360 | for (ref = expr1->ref; ref; ref = ref->next) | |
361 | { | |
362 | if (ref->type == REF_COMPONENT && ref->u.c.component->pointer) | |
363 | return 1; | |
364 | } | |
365 | ||
366 | switch (expr2->expr_type) | |
367 | { | |
368 | case EXPR_OP: | |
dded0b23 | 369 | n = gfc_check_dependency (expr1, expr2->value.op.op1, identical); |
4ee9c684 | 370 | if (n) |
371 | return n; | |
9b773341 | 372 | if (expr2->value.op.op2) |
dded0b23 | 373 | return gfc_check_dependency (expr1, expr2->value.op.op2, identical); |
4ee9c684 | 374 | return 0; |
375 | ||
376 | case EXPR_VARIABLE: | |
377 | if (expr2->symtree->n.sym->attr.pointer) | |
378 | return 1; | |
379 | ||
380 | for (ref = expr2->ref; ref; ref = ref->next) | |
381 | { | |
382 | if (ref->type == REF_COMPONENT && ref->u.c.component->pointer) | |
383 | return 1; | |
384 | } | |
385 | ||
386 | if (expr1->symtree->n.sym != expr2->symtree->n.sym) | |
387 | return 0; | |
388 | ||
dded0b23 | 389 | if (identical) |
390 | return 1; | |
391 | ||
392 | /* Identical ranges return 0, overlapping ranges return 1. */ | |
393 | ||
394 | /* Return zero if we refer to the same full arrays. */ | |
395 | if (expr1->ref->type == REF_ARRAY | |
396 | && expr2->ref->type == REF_ARRAY | |
397 | && expr1->ref->u.ar.type == AR_FULL | |
398 | && expr2->ref->u.ar.type == AR_FULL | |
399 | && !expr1->ref->next | |
400 | && !expr2->ref->next) | |
401 | return 0; | |
402 | ||
4ee9c684 | 403 | return 1; |
404 | ||
405 | case EXPR_FUNCTION: | |
dded0b23 | 406 | if (expr2->inline_noncopying_intrinsic) |
407 | identical = 1; | |
231e961a | 408 | /* Remember possible differences between elemental and |
4ee9c684 | 409 | transformational functions. All functions inside a FORALL |
410 | will be pure. */ | |
411 | for (actual = expr2->value.function.actual; | |
412 | actual; actual = actual->next) | |
413 | { | |
414 | if (!actual->expr) | |
415 | continue; | |
dded0b23 | 416 | n = gfc_check_dependency (expr1, actual->expr, identical); |
4ee9c684 | 417 | if (n) |
418 | return n; | |
419 | } | |
420 | return 0; | |
421 | ||
422 | case EXPR_CONSTANT: | |
423 | return 0; | |
424 | ||
425 | case EXPR_ARRAY: | |
426 | /* Probably ok in the majority of (constant) cases. */ | |
427 | return 1; | |
428 | ||
429 | default: | |
430 | return 1; | |
431 | } | |
432 | } | |
433 | ||
434 | ||
435 | /* Calculates size of the array reference using lower bound, upper bound | |
436 | and stride. */ | |
437 | ||
438 | static void | |
439 | get_no_of_elements(mpz_t ele, gfc_expr * u1, gfc_expr * l1, gfc_expr * s1) | |
440 | { | |
441 | /* nNoOfEle = (u1-l1)/s1 */ | |
442 | ||
443 | mpz_sub (ele, u1->value.integer, l1->value.integer); | |
444 | ||
445 | if (s1 != NULL) | |
446 | mpz_tdiv_q (ele, ele, s1->value.integer); | |
447 | } | |
448 | ||
449 | ||
450 | /* Returns if the ranges ((0..Y), (X1..X2)) overlap. */ | |
451 | ||
452 | static gfc_dependency | |
453 | get_deps (mpz_t x1, mpz_t x2, mpz_t y) | |
454 | { | |
455 | int start; | |
456 | int end; | |
457 | ||
458 | start = mpz_cmp_ui (x1, 0); | |
459 | end = mpz_cmp (x2, y); | |
460 | ||
461 | /* Both ranges the same. */ | |
462 | if (start == 0 && end == 0) | |
463 | return GFC_DEP_EQUAL; | |
464 | ||
465 | /* Distinct ranges. */ | |
466 | if ((start < 0 && mpz_cmp_ui (x2, 0) < 0) | |
467 | || (mpz_cmp (x1, y) > 0 && end > 0)) | |
468 | return GFC_DEP_NODEP; | |
469 | ||
470 | /* Overlapping, but with corresponding elements of the second range | |
471 | greater than the first. */ | |
472 | if (start > 0 && end > 0) | |
473 | return GFC_DEP_FORWARD; | |
474 | ||
475 | /* Overlapping in some other way. */ | |
476 | return GFC_DEP_OVERLAP; | |
477 | } | |
478 | ||
479 | ||
ef833b98 | 480 | /* Perform the same linear transformation on sections l and r such that |
4ee9c684 | 481 | (l_start:l_end:l_stride) -> (0:no_of_elements) |
482 | (r_start:r_end:r_stride) -> (X1:X2) | |
483 | Where r_end is implicit as both sections must have the same number of | |
7b3423b9 | 484 | elements. |
4ee9c684 | 485 | Returns 0 on success, 1 of the transformation failed. */ |
486 | /* TODO: Should this be (0:no_of_elements-1) */ | |
487 | ||
488 | static int | |
489 | transform_sections (mpz_t X1, mpz_t X2, mpz_t no_of_elements, | |
490 | gfc_expr * l_start, gfc_expr * l_end, gfc_expr * l_stride, | |
491 | gfc_expr * r_start, gfc_expr * r_stride) | |
492 | { | |
493 | if (NULL == l_start || NULL == l_end || NULL == r_start) | |
494 | return 1; | |
495 | ||
496 | /* TODO : Currently we check the dependency only when start, end and stride | |
497 | are constant. We could also check for equal (variable) values, and | |
498 | common subexpressions, eg. x vs. x+1. */ | |
499 | ||
500 | if (l_end->expr_type != EXPR_CONSTANT | |
501 | || l_start->expr_type != EXPR_CONSTANT | |
502 | || r_start->expr_type != EXPR_CONSTANT | |
503 | || ((NULL != l_stride) && (l_stride->expr_type != EXPR_CONSTANT)) | |
504 | || ((NULL != r_stride) && (r_stride->expr_type != EXPR_CONSTANT))) | |
505 | { | |
506 | return 1; | |
507 | } | |
508 | ||
509 | ||
510 | get_no_of_elements (no_of_elements, l_end, l_start, l_stride); | |
511 | ||
512 | mpz_sub (X1, r_start->value.integer, l_start->value.integer); | |
513 | if (l_stride != NULL) | |
514 | mpz_cdiv_q (X1, X1, l_stride->value.integer); | |
515 | ||
516 | if (r_stride == NULL) | |
517 | mpz_set (X2, no_of_elements); | |
518 | else | |
519 | mpz_mul (X2, no_of_elements, r_stride->value.integer); | |
520 | ||
521 | if (l_stride != NULL) | |
ef833b98 | 522 | mpz_cdiv_q (X2, X2, l_stride->value.integer); |
4ee9c684 | 523 | mpz_add (X2, X2, X1); |
524 | ||
525 | return 0; | |
526 | } | |
527 | ||
528 | ||
529 | /* Determines overlapping for two array sections. */ | |
530 | ||
531 | static gfc_dependency | |
532 | gfc_check_section_vs_section (gfc_ref * lref, gfc_ref * rref, int n) | |
533 | { | |
534 | gfc_expr *l_start; | |
535 | gfc_expr *l_end; | |
536 | gfc_expr *l_stride; | |
537 | ||
538 | gfc_expr *r_start; | |
539 | gfc_expr *r_stride; | |
540 | ||
541 | gfc_array_ref l_ar; | |
542 | gfc_array_ref r_ar; | |
543 | ||
544 | mpz_t no_of_elements; | |
545 | mpz_t X1, X2; | |
546 | gfc_dependency dep; | |
547 | ||
548 | l_ar = lref->u.ar; | |
549 | r_ar = rref->u.ar; | |
550 | ||
551 | l_start = l_ar.start[n]; | |
552 | l_end = l_ar.end[n]; | |
553 | l_stride = l_ar.stride[n]; | |
554 | r_start = r_ar.start[n]; | |
555 | r_stride = r_ar.stride[n]; | |
556 | ||
557 | /* if l_start is NULL take it from array specifier */ | |
558 | if (NULL == l_start && IS_ARRAY_EXPLICIT(l_ar.as)) | |
559 | l_start = l_ar.as->lower[n]; | |
560 | ||
561 | /* if l_end is NULL take it from array specifier */ | |
562 | if (NULL == l_end && IS_ARRAY_EXPLICIT(l_ar.as)) | |
563 | l_end = l_ar.as->upper[n]; | |
564 | ||
565 | /* if r_start is NULL take it from array specifier */ | |
566 | if (NULL == r_start && IS_ARRAY_EXPLICIT(r_ar.as)) | |
567 | r_start = r_ar.as->lower[n]; | |
568 | ||
569 | mpz_init (X1); | |
570 | mpz_init (X2); | |
571 | mpz_init (no_of_elements); | |
572 | ||
573 | if (transform_sections (X1, X2, no_of_elements, | |
574 | l_start, l_end, l_stride, | |
575 | r_start, r_stride)) | |
576 | dep = GFC_DEP_OVERLAP; | |
577 | else | |
578 | dep = get_deps (X1, X2, no_of_elements); | |
579 | ||
580 | mpz_clear (no_of_elements); | |
581 | mpz_clear (X1); | |
582 | mpz_clear (X2); | |
583 | return dep; | |
584 | } | |
585 | ||
586 | ||
587 | /* Checks if the expr chk is inside the range left-right. | |
588 | Returns GFC_DEP_NODEP if chk is outside the range, | |
589 | GFC_DEP_OVERLAP otherwise. | |
590 | Assumes left<=right. */ | |
591 | ||
592 | static gfc_dependency | |
593 | gfc_is_inside_range (gfc_expr * chk, gfc_expr * left, gfc_expr * right) | |
594 | { | |
595 | int l; | |
596 | int r; | |
597 | int s; | |
598 | ||
599 | s = gfc_dep_compare_expr (left, right); | |
600 | if (s == -2) | |
601 | return GFC_DEP_OVERLAP; | |
602 | ||
603 | l = gfc_dep_compare_expr (chk, left); | |
604 | r = gfc_dep_compare_expr (chk, right); | |
605 | ||
606 | /* Check for indeterminate relationships. */ | |
607 | if (l == -2 || r == -2 || s == -2) | |
608 | return GFC_DEP_OVERLAP; | |
609 | ||
610 | if (s == 1) | |
611 | { | |
612 | /* When left>right we want to check for right <= chk <= left. */ | |
613 | if (l <= 0 || r >= 0) | |
614 | return GFC_DEP_OVERLAP; | |
615 | } | |
616 | else | |
617 | { | |
618 | /* Otherwise check for left <= chk <= right. */ | |
619 | if (l >= 0 || r <= 0) | |
620 | return GFC_DEP_OVERLAP; | |
621 | } | |
622 | ||
623 | return GFC_DEP_NODEP; | |
624 | } | |
625 | ||
626 | ||
627 | /* Determines overlapping for a single element and a section. */ | |
628 | ||
629 | static gfc_dependency | |
630 | gfc_check_element_vs_section( gfc_ref * lref, gfc_ref * rref, int n) | |
631 | { | |
632 | gfc_array_ref l_ar; | |
633 | gfc_array_ref r_ar; | |
634 | gfc_expr *l_start; | |
635 | gfc_expr *r_start; | |
636 | gfc_expr *r_end; | |
637 | ||
638 | l_ar = lref->u.ar; | |
639 | r_ar = rref->u.ar; | |
640 | l_start = l_ar.start[n] ; | |
641 | r_start = r_ar.start[n] ; | |
642 | r_end = r_ar.end[n] ; | |
643 | if (NULL == r_start && IS_ARRAY_EXPLICIT (r_ar.as)) | |
644 | r_start = r_ar.as->lower[n]; | |
645 | if (NULL == r_end && IS_ARRAY_EXPLICIT (r_ar.as)) | |
646 | r_end = r_ar.as->upper[n]; | |
647 | if (NULL == r_start || NULL == r_end || l_start == NULL) | |
648 | return GFC_DEP_OVERLAP; | |
649 | ||
650 | return gfc_is_inside_range (l_start, r_end, r_start); | |
651 | } | |
652 | ||
653 | ||
654 | /* Determines overlapping for two single element array references. */ | |
655 | ||
656 | static gfc_dependency | |
657 | gfc_check_element_vs_element (gfc_ref * lref, gfc_ref * rref, int n) | |
658 | { | |
659 | gfc_array_ref l_ar; | |
660 | gfc_array_ref r_ar; | |
661 | gfc_expr *l_start; | |
662 | gfc_expr *r_start; | |
663 | gfc_dependency nIsDep; | |
664 | ||
665 | if (lref->type == REF_ARRAY && rref->type == REF_ARRAY) | |
666 | { | |
667 | l_ar = lref->u.ar; | |
668 | r_ar = rref->u.ar; | |
669 | l_start = l_ar.start[n] ; | |
670 | r_start = r_ar.start[n] ; | |
671 | if (gfc_dep_compare_expr (r_start, l_start) == 0) | |
672 | nIsDep = GFC_DEP_EQUAL; | |
673 | else | |
674 | nIsDep = GFC_DEP_NODEP; | |
675 | } | |
676 | else | |
677 | nIsDep = GFC_DEP_NODEP; | |
678 | ||
679 | return nIsDep; | |
680 | } | |
681 | ||
682 | ||
683 | /* Finds if two array references are overlapping or not. | |
684 | Return value | |
685 | 1 : array references are overlapping. | |
686 | 0 : array references are not overlapping. */ | |
687 | ||
688 | int | |
689 | gfc_dep_resolver (gfc_ref * lref, gfc_ref * rref) | |
690 | { | |
691 | int n; | |
692 | gfc_dependency fin_dep; | |
693 | gfc_dependency this_dep; | |
694 | ||
695 | ||
696 | fin_dep = GFC_DEP_ERROR; | |
697 | /* Dependencies due to pointers should already have been identified. | |
698 | We only need to check for overlapping array references. */ | |
699 | ||
700 | while (lref && rref) | |
701 | { | |
702 | /* We're resolving from the same base symbol, so both refs should be | |
703 | the same type. We traverse the reference chain intil we find ranges | |
704 | that are not equal. */ | |
22d678e8 | 705 | gcc_assert (lref->type == rref->type); |
4ee9c684 | 706 | switch (lref->type) |
707 | { | |
708 | case REF_COMPONENT: | |
709 | /* The two ranges can't overlap if they are from different | |
710 | components. */ | |
711 | if (lref->u.c.component != rref->u.c.component) | |
712 | return 0; | |
713 | break; | |
714 | ||
715 | case REF_SUBSTRING: | |
716 | /* Substring overlaps are handled by the string assignment code. */ | |
717 | return 0; | |
718 | ||
719 | case REF_ARRAY: | |
720 | ||
721 | for (n=0; n < lref->u.ar.dimen; n++) | |
722 | { | |
723 | /* Assume dependency when either of array reference is vector | |
724 | subscript. */ | |
725 | if (lref->u.ar.dimen_type[n] == DIMEN_VECTOR | |
726 | || rref->u.ar.dimen_type[n] == DIMEN_VECTOR) | |
727 | return 1; | |
728 | if (lref->u.ar.dimen_type[n] == DIMEN_RANGE | |
729 | && rref->u.ar.dimen_type[n] == DIMEN_RANGE) | |
730 | this_dep = gfc_check_section_vs_section (lref, rref, n); | |
731 | else if (lref->u.ar.dimen_type[n] == DIMEN_ELEMENT | |
732 | && rref->u.ar.dimen_type[n] == DIMEN_RANGE) | |
733 | this_dep = gfc_check_element_vs_section (lref, rref, n); | |
734 | else if (rref->u.ar.dimen_type[n] == DIMEN_ELEMENT | |
735 | && lref->u.ar.dimen_type[n] == DIMEN_RANGE) | |
736 | this_dep = gfc_check_element_vs_section (rref, lref, n); | |
737 | else | |
738 | { | |
22d678e8 | 739 | gcc_assert (rref->u.ar.dimen_type[n] == DIMEN_ELEMENT |
4ee9c684 | 740 | && lref->u.ar.dimen_type[n] == DIMEN_ELEMENT); |
741 | this_dep = gfc_check_element_vs_element (rref, lref, n); | |
742 | } | |
743 | ||
744 | /* If any dimension doesn't overlap, we have no dependency. */ | |
745 | if (this_dep == GFC_DEP_NODEP) | |
746 | return 0; | |
747 | ||
748 | /* Overlap codes are in order of priority. We only need to | |
749 | know the worst one.*/ | |
750 | if (this_dep > fin_dep) | |
751 | fin_dep = this_dep; | |
752 | } | |
753 | /* Exactly matching and forward overlapping ranges don't cause a | |
754 | dependency. */ | |
755 | if (fin_dep < GFC_DEP_OVERLAP) | |
756 | return 0; | |
757 | ||
758 | /* Keep checking. We only have a dependency if | |
759 | subsequent references also overlap. */ | |
760 | break; | |
761 | ||
762 | default: | |
22d678e8 | 763 | gcc_unreachable (); |
4ee9c684 | 764 | } |
765 | lref = lref->next; | |
766 | rref = rref->next; | |
767 | } | |
768 | ||
769 | /* If we haven't seen any array refs then something went wrong. */ | |
22d678e8 | 770 | gcc_assert (fin_dep != GFC_DEP_ERROR); |
4ee9c684 | 771 | |
772 | if (fin_dep < GFC_DEP_OVERLAP) | |
773 | return 0; | |
774 | else | |
775 | return 1; | |
776 | } | |
777 |