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1b727a0a | 1 | /* Code to analyze doloop loops in order for targets to perform late |
2 | optimizations converting doloops to other forms of hardware loops. | |
3 | Copyright (C) 2011 Free Software Foundation, Inc. | |
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 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
24 | #include "tm.h" | |
25 | #include "rtl.h" | |
26 | #include "flags.h" | |
27 | #include "expr.h" | |
28 | #include "hard-reg-set.h" | |
29 | #include "regs.h" | |
30 | #include "basic-block.h" | |
31 | #include "tm_p.h" | |
32 | #include "df.h" | |
1b727a0a | 33 | #include "cfgloop.h" |
1b727a0a | 34 | #include "recog.h" |
35 | #include "target.h" | |
36 | #include "hw-doloop.h" | |
b9ed1410 | 37 | #include "dumpfile.h" |
1b727a0a | 38 | |
39 | #ifdef HAVE_doloop_end | |
40 | ||
41 | /* Dump information collected in LOOPS. */ | |
42 | static void | |
43 | dump_hwloops (hwloop_info loops) | |
44 | { | |
45 | hwloop_info loop; | |
46 | ||
47 | for (loop = loops; loop; loop = loop->next) | |
48 | { | |
49 | hwloop_info i; | |
50 | basic_block b; | |
51 | unsigned ix; | |
52 | ||
53 | fprintf (dump_file, ";; loop %d: ", loop->loop_no); | |
54 | if (loop->bad) | |
55 | fprintf (dump_file, "(bad) "); | |
56 | fprintf (dump_file, "{head:%d, depth:%d, reg:%u}", | |
57 | loop->head == NULL ? -1 : loop->head->index, | |
58 | loop->depth, REGNO (loop->iter_reg)); | |
59 | ||
60 | fprintf (dump_file, " blocks: [ "); | |
f1f41a6c | 61 | for (ix = 0; loop->blocks.iterate (ix, &b); ix++) |
1b727a0a | 62 | fprintf (dump_file, "%d ", b->index); |
63 | fprintf (dump_file, "] "); | |
64 | ||
65 | fprintf (dump_file, " inner loops: [ "); | |
f1f41a6c | 66 | for (ix = 0; loop->loops.iterate (ix, &i); ix++) |
1b727a0a | 67 | fprintf (dump_file, "%d ", i->loop_no); |
68 | fprintf (dump_file, "]\n"); | |
69 | } | |
70 | fprintf (dump_file, "\n"); | |
71 | } | |
72 | ||
73 | /* Return true if BB is part of LOOP. */ | |
74 | static bool | |
75 | bb_in_loop_p (hwloop_info loop, basic_block bb) | |
76 | { | |
77 | return bitmap_bit_p (loop->block_bitmap, bb->index); | |
78 | } | |
79 | ||
80 | /* Scan the blocks of LOOP (and its inferiors), and record things such as | |
81 | hard registers set, jumps out of and within the loop. */ | |
82 | static void | |
83 | scan_loop (hwloop_info loop) | |
84 | { | |
85 | unsigned ix; | |
86 | basic_block bb; | |
87 | ||
88 | if (loop->bad) | |
89 | return; | |
90 | ||
91 | if (REGNO_REG_SET_P (df_get_live_in (loop->successor), | |
92 | REGNO (loop->iter_reg))) | |
93 | loop->iter_reg_used_outside = true; | |
94 | ||
f1f41a6c | 95 | for (ix = 0; loop->blocks.iterate (ix, &bb); ix++) |
1b727a0a | 96 | { |
97 | rtx insn; | |
98 | edge e; | |
99 | edge_iterator ei; | |
100 | ||
101 | if (bb != loop->tail) | |
102 | FOR_EACH_EDGE (e, ei, bb->succs) | |
103 | { | |
104 | if (bb_in_loop_p (loop, e->dest)) | |
105 | { | |
106 | if (!(e->flags & EDGE_FALLTHRU)) | |
107 | loop->jumps_within = true; | |
108 | } | |
109 | else | |
110 | { | |
111 | loop->jumps_outof = true; | |
112 | if (!loop->bad) | |
113 | gcc_assert (!REGNO_REG_SET_P (df_get_live_in (e->dest), | |
114 | REGNO (loop->iter_reg))); | |
115 | } | |
116 | } | |
117 | ||
118 | for (insn = BB_HEAD (bb); | |
119 | insn != NEXT_INSN (BB_END (bb)); | |
120 | insn = NEXT_INSN (insn)) | |
121 | { | |
122 | df_ref *def_rec; | |
123 | HARD_REG_SET set_this_insn; | |
124 | ||
ee567e6b | 125 | if (!NONDEBUG_INSN_P (insn)) |
1b727a0a | 126 | continue; |
127 | ||
128 | if (recog_memoized (insn) < 0 | |
129 | && (GET_CODE (PATTERN (insn)) == ASM_INPUT | |
130 | || asm_noperands (PATTERN (insn)) >= 0)) | |
131 | loop->has_asm = true; | |
132 | ||
133 | CLEAR_HARD_REG_SET (set_this_insn); | |
134 | for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++) | |
135 | { | |
136 | rtx dreg = DF_REF_REG (*def_rec); | |
137 | ||
138 | if (!REG_P (dreg)) | |
139 | continue; | |
140 | ||
141 | add_to_hard_reg_set (&set_this_insn, GET_MODE (dreg), | |
142 | REGNO (dreg)); | |
143 | } | |
144 | ||
145 | if (insn == loop->loop_end) | |
146 | CLEAR_HARD_REG_BIT (set_this_insn, REGNO (loop->iter_reg)); | |
147 | else if (reg_mentioned_p (loop->iter_reg, PATTERN (insn))) | |
148 | loop->iter_reg_used = true; | |
149 | IOR_HARD_REG_SET (loop->regs_set_in_loop, set_this_insn); | |
150 | } | |
151 | } | |
152 | } | |
153 | ||
154 | /* Compute the incoming_dest and incoming_src members of LOOP by | |
155 | identifying the edges that jump into the loop. If there is more | |
156 | than one block that jumps into the loop, incoming_src will be set | |
157 | to NULL; likewise, if there is more than one block in the loop that | |
158 | is the destination of an incoming edge, incoming_dest will be NULL. | |
159 | ||
160 | Return true if either of these two fields is nonnull, false | |
161 | otherwise. */ | |
162 | static bool | |
163 | process_incoming_edges (hwloop_info loop) | |
164 | { | |
165 | edge e; | |
166 | edge_iterator ei; | |
167 | bool first = true; | |
168 | ||
169 | FOR_EACH_EDGE (e, ei, loop->incoming) | |
170 | { | |
171 | if (first) | |
172 | { | |
173 | loop->incoming_src = e->src; | |
174 | loop->incoming_dest = e->dest; | |
175 | first = false; | |
176 | } | |
177 | else | |
178 | { | |
179 | if (e->dest != loop->incoming_dest) | |
180 | loop->incoming_dest = NULL; | |
181 | if (e->src != loop->incoming_src) | |
182 | loop->incoming_src = NULL; | |
183 | } | |
184 | } | |
185 | if (loop->incoming_src == NULL && loop->incoming_dest == NULL) | |
186 | return false; | |
187 | ||
188 | return true; | |
189 | } | |
190 | ||
191 | /* Try to identify a forwarder block that jump into LOOP, and add it to | |
192 | the set of blocks in the loop, updating the vector of incoming blocks as | |
193 | well. This transformation gives a second chance to loops we couldn't | |
194 | otherwise handle by increasing the chance that we'll end up with one | |
195 | incoming_src block. | |
196 | Return true if we made a change, false otherwise. */ | |
197 | static bool | |
198 | add_forwarder_blocks (hwloop_info loop) | |
199 | { | |
200 | edge e; | |
201 | edge_iterator ei; | |
202 | ||
203 | FOR_EACH_EDGE (e, ei, loop->incoming) | |
204 | { | |
205 | if (forwarder_block_p (e->src)) | |
206 | { | |
207 | edge e2; | |
208 | edge_iterator ei2; | |
209 | ||
210 | if (dump_file) | |
211 | fprintf (dump_file, | |
212 | ";; Adding forwarder block %d to loop %d and retrying\n", | |
213 | e->src->index, loop->loop_no); | |
f1f41a6c | 214 | loop->blocks.safe_push (e->src); |
1b727a0a | 215 | bitmap_set_bit (loop->block_bitmap, e->src->index); |
216 | FOR_EACH_EDGE (e2, ei2, e->src->preds) | |
f1f41a6c | 217 | vec_safe_push (loop->incoming, e2); |
218 | loop->incoming->unordered_remove (ei.index); | |
1b727a0a | 219 | return true; |
220 | } | |
221 | } | |
222 | return false; | |
223 | } | |
224 | ||
225 | /* Called from reorg_loops when a potential loop end is found. LOOP is | |
226 | a newly set up structure describing the loop, it is this function's | |
227 | responsibility to fill most of it. TAIL_BB and TAIL_INSN point to the | |
228 | loop_end insn and its enclosing basic block. REG is the loop counter | |
229 | register. | |
230 | For our purposes, a loop is defined by the set of blocks reachable from | |
231 | the loop head in which the loop counter register is live. This matches | |
232 | the expected use; targets that call into this code usually replace the | |
233 | loop counter with a different special register. */ | |
234 | static void | |
235 | discover_loop (hwloop_info loop, basic_block tail_bb, rtx tail_insn, rtx reg) | |
236 | { | |
237 | bool found_tail; | |
238 | unsigned dwork = 0; | |
239 | basic_block bb; | |
f1f41a6c | 240 | vec<basic_block> works; |
1b727a0a | 241 | |
242 | loop->tail = tail_bb; | |
243 | loop->loop_end = tail_insn; | |
244 | loop->iter_reg = reg; | |
f1f41a6c | 245 | vec_alloc (loop->incoming, 2); |
1b727a0a | 246 | loop->start_label = JUMP_LABEL (tail_insn); |
247 | ||
248 | if (EDGE_COUNT (tail_bb->succs) != 2) | |
249 | { | |
250 | loop->bad = true; | |
251 | return; | |
252 | } | |
253 | loop->head = BRANCH_EDGE (tail_bb)->dest; | |
254 | loop->successor = FALLTHRU_EDGE (tail_bb)->dest; | |
255 | ||
f1f41a6c | 256 | works.create (20); |
257 | works.safe_push (loop->head); | |
1b727a0a | 258 | |
259 | found_tail = false; | |
f1f41a6c | 260 | for (dwork = 0; works.iterate (dwork, &bb); dwork++) |
1b727a0a | 261 | { |
262 | edge e; | |
263 | edge_iterator ei; | |
264 | if (bb == EXIT_BLOCK_PTR) | |
265 | { | |
266 | /* We've reached the exit block. The loop must be bad. */ | |
267 | if (dump_file) | |
268 | fprintf (dump_file, | |
269 | ";; Loop is bad - reached exit block while scanning\n"); | |
270 | loop->bad = true; | |
271 | break; | |
272 | } | |
273 | ||
274 | if (bitmap_bit_p (loop->block_bitmap, bb->index)) | |
275 | continue; | |
276 | ||
277 | /* We've not seen this block before. Add it to the loop's | |
278 | list and then add each successor to the work list. */ | |
279 | ||
f1f41a6c | 280 | loop->blocks.safe_push (bb); |
1b727a0a | 281 | bitmap_set_bit (loop->block_bitmap, bb->index); |
282 | ||
283 | if (bb == tail_bb) | |
284 | found_tail = true; | |
285 | else | |
286 | { | |
287 | FOR_EACH_EDGE (e, ei, bb->succs) | |
288 | { | |
289 | basic_block succ = EDGE_SUCC (bb, ei.index)->dest; | |
290 | if (REGNO_REG_SET_P (df_get_live_in (succ), | |
291 | REGNO (loop->iter_reg))) | |
f1f41a6c | 292 | works.safe_push (succ); |
1b727a0a | 293 | } |
294 | } | |
295 | } | |
296 | ||
297 | if (!found_tail) | |
298 | loop->bad = true; | |
299 | ||
300 | /* Find the predecessor, and make sure nothing else jumps into this loop. */ | |
301 | if (!loop->bad) | |
302 | { | |
f1f41a6c | 303 | FOR_EACH_VEC_ELT (loop->blocks, dwork, bb) |
1b727a0a | 304 | { |
305 | edge e; | |
306 | edge_iterator ei; | |
307 | FOR_EACH_EDGE (e, ei, bb->preds) | |
308 | { | |
309 | basic_block pred = e->src; | |
310 | ||
311 | if (!bb_in_loop_p (loop, pred)) | |
312 | { | |
313 | if (dump_file) | |
314 | fprintf (dump_file, ";; Loop %d: incoming edge %d -> %d\n", | |
315 | loop->loop_no, pred->index, | |
316 | e->dest->index); | |
f1f41a6c | 317 | vec_safe_push (loop->incoming, e); |
1b727a0a | 318 | } |
319 | } | |
320 | } | |
321 | ||
322 | if (!process_incoming_edges (loop)) | |
323 | { | |
324 | if (dump_file) | |
325 | fprintf (dump_file, | |
326 | ";; retrying loop %d with forwarder blocks\n", | |
327 | loop->loop_no); | |
328 | if (!add_forwarder_blocks (loop)) | |
329 | { | |
330 | if (dump_file) | |
331 | fprintf (dump_file, ";; No forwarder blocks found\n"); | |
332 | loop->bad = true; | |
333 | } | |
334 | else if (!process_incoming_edges (loop)) | |
335 | { | |
336 | if (dump_file) | |
337 | fprintf (dump_file, | |
338 | ";; can't find suitable entry for loop %d\n", | |
339 | loop->loop_no); | |
340 | } | |
341 | } | |
342 | } | |
343 | ||
f1f41a6c | 344 | works.release (); |
1b727a0a | 345 | } |
346 | ||
347 | /* Analyze the structure of the loops in the current function. Use | |
2b15d2ba | 348 | LOOP_STACK for bitmap allocations. Returns all the valid candidates for |
1b727a0a | 349 | hardware loops found in this function. HOOKS is the argument |
350 | passed to reorg_loops, used here to find the iteration registers | |
351 | from a loop_end pattern. */ | |
352 | static hwloop_info | |
2b15d2ba | 353 | discover_loops (bitmap_obstack *loop_stack, struct hw_doloop_hooks *hooks) |
1b727a0a | 354 | { |
355 | hwloop_info loops = NULL; | |
356 | hwloop_info loop; | |
357 | basic_block bb; | |
358 | int nloops = 0; | |
359 | ||
360 | /* Find all the possible loop tails. This means searching for every | |
361 | loop_end instruction. For each one found, create a hwloop_info | |
362 | structure and add the head block to the work list. */ | |
363 | FOR_EACH_BB (bb) | |
364 | { | |
365 | rtx tail = BB_END (bb); | |
366 | rtx insn, reg; | |
367 | ||
368 | while (tail && GET_CODE (tail) == NOTE && tail != BB_HEAD (bb)) | |
369 | tail = PREV_INSN (tail); | |
370 | ||
371 | if (tail == NULL_RTX) | |
372 | continue; | |
373 | ||
374 | if (!JUMP_P (tail)) | |
375 | continue; | |
376 | reg = hooks->end_pattern_reg (tail); | |
377 | if (reg == NULL_RTX) | |
378 | continue; | |
379 | ||
380 | /* A possible loop end */ | |
381 | ||
382 | /* There's a degenerate case we can handle - an empty loop consisting | |
383 | of only a back branch. Handle that by deleting the branch. */ | |
384 | insn = JUMP_LABEL (tail); | |
385 | while (insn && !NONDEBUG_INSN_P (insn)) | |
386 | insn = NEXT_INSN (insn); | |
387 | if (insn == tail) | |
388 | { | |
389 | basic_block succ = FALLTHRU_EDGE (bb)->dest; | |
390 | if (dump_file) | |
391 | { | |
392 | fprintf (dump_file, ";; degenerate loop ending at\n"); | |
393 | print_rtl_single (dump_file, tail); | |
394 | } | |
395 | if (!REGNO_REG_SET_P (df_get_live_in (succ), REGNO (reg))) | |
396 | { | |
397 | if (dump_file) | |
398 | fprintf (dump_file, ";; deleting it\n"); | |
399 | delete_insn_and_edges (tail); | |
400 | continue; | |
401 | } | |
402 | } | |
403 | ||
404 | loop = XCNEW (struct hwloop_info_d); | |
405 | loop->next = loops; | |
406 | loops = loop; | |
407 | loop->loop_no = nloops++; | |
f1f41a6c | 408 | loop->blocks.create (20); |
2b15d2ba | 409 | loop->block_bitmap = BITMAP_ALLOC (loop_stack); |
1b727a0a | 410 | |
411 | if (dump_file) | |
412 | { | |
413 | fprintf (dump_file, ";; potential loop %d ending at\n", | |
414 | loop->loop_no); | |
415 | print_rtl_single (dump_file, tail); | |
416 | } | |
417 | ||
418 | discover_loop (loop, bb, tail, reg); | |
419 | } | |
420 | ||
421 | /* Compute loop nestings. Given two loops A and B, either the sets | |
422 | of their blocks don't intersect at all, or one is the subset of | |
423 | the other, or the blocks don't form a good nesting structure. */ | |
424 | for (loop = loops; loop; loop = loop->next) | |
425 | { | |
426 | hwloop_info other; | |
427 | ||
428 | if (loop->bad) | |
429 | continue; | |
430 | ||
431 | for (other = loops; other; other = other->next) | |
432 | { | |
433 | if (other->bad) | |
434 | continue; | |
435 | ||
436 | if (!bitmap_intersect_p (other->block_bitmap, loop->block_bitmap)) | |
437 | continue; | |
438 | if (!bitmap_intersect_compl_p (other->block_bitmap, | |
439 | loop->block_bitmap)) | |
f1f41a6c | 440 | loop->loops.safe_push (other); |
1b727a0a | 441 | else if (!bitmap_intersect_compl_p (loop->block_bitmap, |
442 | other->block_bitmap)) | |
f1f41a6c | 443 | other->loops.safe_push (loop); |
1b727a0a | 444 | else |
445 | { | |
446 | if (dump_file) | |
447 | fprintf (dump_file, | |
448 | ";; can't find suitable nesting for loops %d and %d\n", | |
449 | loop->loop_no, other->loop_no); | |
450 | loop->bad = other->bad = true; | |
451 | } | |
452 | } | |
453 | } | |
454 | ||
455 | if (dump_file) | |
456 | dump_hwloops (loops); | |
457 | ||
458 | return loops; | |
459 | } | |
460 | ||
461 | /* Free up the loop structures in LOOPS. */ | |
462 | static void | |
463 | free_loops (hwloop_info loops) | |
464 | { | |
465 | while (loops) | |
466 | { | |
467 | hwloop_info loop = loops; | |
468 | loops = loop->next; | |
f1f41a6c | 469 | loop->loops.release (); |
470 | loop->blocks.release (); | |
1b727a0a | 471 | BITMAP_FREE (loop->block_bitmap); |
472 | XDELETE (loop); | |
473 | } | |
474 | } | |
475 | ||
476 | #define BB_AUX_INDEX(BB) ((intptr_t) (BB)->aux) | |
477 | ||
478 | /* Initialize the aux fields to give ascending indices to basic blocks. */ | |
479 | static void | |
480 | set_bb_indices (void) | |
481 | { | |
482 | basic_block bb; | |
483 | intptr_t index; | |
484 | ||
485 | index = 0; | |
486 | FOR_EACH_BB (bb) | |
487 | bb->aux = (void *) index++; | |
488 | } | |
489 | ||
490 | /* The taken-branch edge from the loop end can actually go forward. | |
491 | If the target's hardware loop support requires that the loop end be | |
492 | after the loop start, try to reorder a loop's basic blocks when we | |
493 | find such a case. | |
494 | This is not very aggressive; it only moves at most one block. It | |
495 | does not introduce new branches into loops; it may remove them, or | |
496 | it may switch fallthru/jump edges. */ | |
497 | static void | |
498 | reorder_loops (hwloop_info loops) | |
499 | { | |
500 | basic_block bb; | |
501 | hwloop_info loop; | |
502 | ||
503 | cfg_layout_initialize (0); | |
504 | ||
505 | set_bb_indices (); | |
506 | ||
507 | for (loop = loops; loop; loop = loop->next) | |
508 | { | |
509 | edge e; | |
510 | edge_iterator ei; | |
511 | ||
512 | if (loop->bad) | |
513 | continue; | |
514 | ||
515 | if (BB_AUX_INDEX (loop->head) <= BB_AUX_INDEX (loop->tail)) | |
516 | continue; | |
517 | ||
518 | FOR_EACH_EDGE (e, ei, loop->head->succs) | |
519 | { | |
520 | if (bitmap_bit_p (loop->block_bitmap, e->dest->index) | |
521 | && BB_AUX_INDEX (e->dest) < BB_AUX_INDEX (loop->tail)) | |
522 | { | |
523 | basic_block start_bb = e->dest; | |
524 | basic_block start_prev_bb = start_bb->prev_bb; | |
525 | ||
526 | if (dump_file) | |
527 | fprintf (dump_file, ";; Moving block %d before block %d\n", | |
528 | loop->head->index, start_bb->index); | |
529 | loop->head->prev_bb->next_bb = loop->head->next_bb; | |
530 | loop->head->next_bb->prev_bb = loop->head->prev_bb; | |
531 | ||
532 | loop->head->prev_bb = start_prev_bb; | |
533 | loop->head->next_bb = start_bb; | |
534 | start_prev_bb->next_bb = start_bb->prev_bb = loop->head; | |
535 | ||
536 | set_bb_indices (); | |
537 | break; | |
538 | } | |
539 | } | |
540 | loops = loops->next; | |
541 | } | |
542 | ||
543 | FOR_EACH_BB (bb) | |
544 | { | |
545 | if (bb->next_bb != EXIT_BLOCK_PTR) | |
546 | bb->aux = bb->next_bb; | |
547 | else | |
548 | bb->aux = NULL; | |
549 | } | |
550 | cfg_layout_finalize (); | |
551 | clear_aux_for_blocks (); | |
552 | df_analyze (); | |
553 | } | |
554 | ||
555 | /* Call the OPT function for LOOP and all of its sub-loops. This is | |
556 | done in a depth-first search; innermost loops are visited first. | |
557 | OPTIMIZE and FAIL are the functions passed to reorg_loops by the | |
558 | target's reorg pass. */ | |
559 | static void | |
560 | optimize_loop (hwloop_info loop, struct hw_doloop_hooks *hooks) | |
561 | { | |
562 | int ix; | |
563 | hwloop_info inner; | |
564 | int inner_depth = 0; | |
565 | ||
566 | if (loop->visited) | |
567 | return; | |
568 | ||
569 | loop->visited = 1; | |
570 | ||
571 | if (loop->bad) | |
572 | { | |
573 | if (dump_file) | |
574 | fprintf (dump_file, ";; loop %d bad when found\n", loop->loop_no); | |
575 | goto bad_loop; | |
576 | } | |
577 | ||
578 | /* Every loop contains in its list of inner loops every loop nested inside | |
579 | it, even if there are intermediate loops. This works because we're doing | |
580 | a depth-first search here and never visit a loop more than once. | |
581 | Recursion depth is effectively limited by the number of available | |
582 | hardware registers. */ | |
f1f41a6c | 583 | for (ix = 0; loop->loops.iterate (ix, &inner); ix++) |
1b727a0a | 584 | { |
585 | optimize_loop (inner, hooks); | |
586 | ||
587 | if (!inner->bad && inner_depth < inner->depth) | |
588 | inner_depth = inner->depth; | |
589 | /* The set of registers may be changed while optimizing the inner | |
590 | loop. */ | |
591 | IOR_HARD_REG_SET (loop->regs_set_in_loop, inner->regs_set_in_loop); | |
592 | } | |
593 | ||
594 | loop->depth = inner_depth + 1; | |
595 | ||
596 | if (hooks->opt (loop)) | |
597 | return; | |
598 | ||
599 | bad_loop: | |
600 | if (dump_file) | |
601 | fprintf (dump_file, ";; loop %d is bad\n", loop->loop_no); | |
602 | ||
603 | loop->bad = true; | |
604 | hooks->fail (loop); | |
605 | } | |
606 | ||
607 | /* This function can be used from a port's machine_dependent_reorg to | |
608 | find and analyze loops that end in loop_end instructions. It uses | |
609 | a set of function pointers in HOOKS to call back into the | |
610 | target-specific functions to perform the actual machine-specific | |
611 | transformations. | |
612 | ||
613 | Such transformations typically involve additional set-up | |
614 | instructions before the loop, to define loop bounds or set up a | |
615 | special loop counter register. | |
616 | ||
617 | DO_REORDER should be set to true if we should try to use the | |
618 | reorder_loops function to ensure the loop end occurs after the loop | |
619 | start. This is for use by targets where the loop hardware requires | |
620 | this condition. | |
621 | ||
622 | HOOKS is used to pass in target specific hooks; see | |
623 | hw-doloop.h. */ | |
624 | void | |
625 | reorg_loops (bool do_reorder, struct hw_doloop_hooks *hooks) | |
626 | { | |
627 | hwloop_info loops = NULL; | |
628 | hwloop_info loop; | |
2b15d2ba | 629 | bitmap_obstack loop_stack; |
1b727a0a | 630 | |
631 | df_live_add_problem (); | |
632 | df_live_set_all_dirty (); | |
633 | df_analyze (); | |
634 | ||
2b15d2ba | 635 | bitmap_obstack_initialize (&loop_stack); |
1b727a0a | 636 | |
637 | if (dump_file) | |
638 | fprintf (dump_file, ";; Find loops, first pass\n\n"); | |
639 | ||
2b15d2ba | 640 | loops = discover_loops (&loop_stack, hooks); |
1b727a0a | 641 | |
642 | if (do_reorder) | |
643 | { | |
644 | reorder_loops (loops); | |
645 | free_loops (loops); | |
646 | ||
647 | if (dump_file) | |
648 | fprintf (dump_file, ";; Find loops, second pass\n\n"); | |
649 | ||
2b15d2ba | 650 | loops = discover_loops (&loop_stack, hooks); |
1b727a0a | 651 | } |
652 | ||
653 | for (loop = loops; loop; loop = loop->next) | |
654 | scan_loop (loop); | |
655 | ||
656 | /* Now apply the optimizations. */ | |
657 | for (loop = loops; loop; loop = loop->next) | |
658 | optimize_loop (loop, hooks); | |
659 | ||
660 | if (dump_file) | |
661 | { | |
662 | fprintf (dump_file, ";; After hardware loops optimization:\n\n"); | |
663 | dump_hwloops (loops); | |
664 | } | |
665 | ||
666 | free_loops (loops); | |
667 | ||
668 | if (dump_file) | |
669 | print_rtl (dump_file, get_insns ()); | |
670 | } | |
671 | #endif |