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ca6c03ca JH |
1 | /* Control flow graph manipulation code for GNU compiler. |
2 | Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, | |
6a58eee9 | 3 | 1999, 2000, 2001, 2002 Free Software Foundation, Inc. |
ca6c03ca JH |
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 2, 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 COPYING. If not, write to the Free | |
19 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
20 | 02111-1307, USA. */ | |
21 | ||
5f0d2358 RK |
22 | /* This file contains low level functions to manipulate the CFG and analyze it |
23 | that are aware of the RTL intermediate language. | |
ca6c03ca JH |
24 | |
25 | Available functionality: | |
5f0d2358 | 26 | - CFG-aware instruction chain manipulation |
ca6c03ca JH |
27 | delete_insn, delete_insn_chain |
28 | - Basic block manipulation | |
5f0d2358 RK |
29 | create_basic_block, flow_delete_block, split_block, |
30 | merge_blocks_nomove | |
31 | - Infrastructure to determine quickly basic block for insn | |
ca6c03ca | 32 | compute_bb_for_insn, update_bb_for_insn, set_block_for_insn, |
5f0d2358 RK |
33 | - Edge redirection with updating and optimizing of insn chain |
34 | block_label, redirect_edge_and_branch, | |
35 | redirect_edge_and_branch_force, tidy_fallthru_edge, force_nonfallthru | |
ca6c03ca | 36 | - Edge splitting and commiting to edges |
5f0d2358 | 37 | split_edge, insert_insn_on_edge, commit_edge_insertions |
eaec9b3d | 38 | - Dumping and debugging |
5f0d2358 | 39 | print_rtl_with_bb, dump_bb, debug_bb, debug_bb_n |
ca6c03ca | 40 | - Consistency checking |
5f0d2358 | 41 | verify_flow_info |
ca6c03ca | 42 | - CFG updating after constant propagation |
5f0d2358 | 43 | purge_dead_edges, purge_all_dead_edges */ |
ca6c03ca JH |
44 | \f |
45 | #include "config.h" | |
46 | #include "system.h" | |
47 | #include "tree.h" | |
48 | #include "rtl.h" | |
49 | #include "hard-reg-set.h" | |
50 | #include "basic-block.h" | |
51 | #include "regs.h" | |
52 | #include "flags.h" | |
53 | #include "output.h" | |
54 | #include "function.h" | |
55 | #include "except.h" | |
56 | #include "toplev.h" | |
57 | #include "tm_p.h" | |
58 | #include "obstack.h" | |
0a2ed1f1 | 59 | #include "insn-config.h" |
ca6c03ca | 60 | |
5f0d2358 | 61 | /* Stubs in case we don't have a return insn. */ |
ca6c03ca JH |
62 | #ifndef HAVE_return |
63 | #define HAVE_return 0 | |
64 | #define gen_return() NULL_RTX | |
65 | #endif | |
66 | ||
67 | /* The basic block structure for every insn, indexed by uid. */ | |
ca6c03ca JH |
68 | varray_type basic_block_for_insn; |
69 | ||
70 | /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */ | |
71 | /* ??? Should probably be using LABEL_NUSES instead. It would take a | |
72 | bit of surgery to be able to use or co-opt the routines in jump. */ | |
ca6c03ca JH |
73 | rtx label_value_list; |
74 | rtx tail_recursion_label_list; | |
75 | ||
76 | static int can_delete_note_p PARAMS ((rtx)); | |
77 | static int can_delete_label_p PARAMS ((rtx)); | |
3dec4024 | 78 | static void commit_one_edge_insertion PARAMS ((edge, int)); |
ca6c03ca JH |
79 | static bool try_redirect_by_replacing_jump PARAMS ((edge, basic_block)); |
80 | static rtx last_loop_beg_note PARAMS ((rtx)); | |
81 | static bool back_edge_of_syntactic_loop_p PARAMS ((basic_block, basic_block)); | |
82 | static basic_block force_nonfallthru_and_redirect PARAMS ((edge, basic_block)); | |
83 | \f | |
84 | /* Return true if NOTE is not one of the ones that must be kept paired, | |
5f0d2358 | 85 | so that we may simply delete it. */ |
ca6c03ca JH |
86 | |
87 | static int | |
88 | can_delete_note_p (note) | |
89 | rtx note; | |
90 | { | |
91 | return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED | |
969d70ca JH |
92 | || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK |
93 | || NOTE_LINE_NUMBER (note) == NOTE_INSN_PREDICTION); | |
ca6c03ca JH |
94 | } |
95 | ||
96 | /* True if a given label can be deleted. */ | |
97 | ||
98 | static int | |
99 | can_delete_label_p (label) | |
100 | rtx label; | |
101 | { | |
5f0d2358 RK |
102 | return (!LABEL_PRESERVE_P (label) |
103 | /* User declared labels must be preserved. */ | |
104 | && LABEL_NAME (label) == 0 | |
105 | && !in_expr_list_p (forced_labels, label) | |
6a58eee9 | 106 | && !in_expr_list_p (label_value_list, label)); |
ca6c03ca JH |
107 | } |
108 | ||
109 | /* Delete INSN by patching it out. Return the next insn. */ | |
110 | ||
111 | rtx | |
112 | delete_insn (insn) | |
113 | rtx insn; | |
114 | { | |
115 | rtx next = NEXT_INSN (insn); | |
116 | rtx note; | |
117 | bool really_delete = true; | |
118 | ||
119 | if (GET_CODE (insn) == CODE_LABEL) | |
120 | { | |
121 | /* Some labels can't be directly removed from the INSN chain, as they | |
122 | might be references via variables, constant pool etc. | |
123 | Convert them to the special NOTE_INSN_DELETED_LABEL note. */ | |
124 | if (! can_delete_label_p (insn)) | |
125 | { | |
126 | const char *name = LABEL_NAME (insn); | |
127 | ||
128 | really_delete = false; | |
129 | PUT_CODE (insn, NOTE); | |
130 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL; | |
131 | NOTE_SOURCE_FILE (insn) = name; | |
132 | } | |
5f0d2358 | 133 | |
ca6c03ca JH |
134 | remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels); |
135 | } | |
136 | ||
137 | if (really_delete) | |
138 | { | |
cda94cbb RH |
139 | /* If this insn has already been deleted, something is very wrong. */ |
140 | if (INSN_DELETED_P (insn)) | |
141 | abort (); | |
ca6c03ca JH |
142 | remove_insn (insn); |
143 | INSN_DELETED_P (insn) = 1; | |
144 | } | |
145 | ||
146 | /* If deleting a jump, decrement the use count of the label. Deleting | |
147 | the label itself should happen in the normal course of block merging. */ | |
148 | if (GET_CODE (insn) == JUMP_INSN | |
149 | && JUMP_LABEL (insn) | |
150 | && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL) | |
151 | LABEL_NUSES (JUMP_LABEL (insn))--; | |
152 | ||
153 | /* Also if deleting an insn that references a label. */ | |
154 | else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX | |
155 | && GET_CODE (XEXP (note, 0)) == CODE_LABEL) | |
156 | LABEL_NUSES (XEXP (note, 0))--; | |
157 | ||
158 | if (GET_CODE (insn) == JUMP_INSN | |
159 | && (GET_CODE (PATTERN (insn)) == ADDR_VEC | |
160 | || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)) | |
161 | { | |
162 | rtx pat = PATTERN (insn); | |
163 | int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC; | |
164 | int len = XVECLEN (pat, diff_vec_p); | |
165 | int i; | |
166 | ||
167 | for (i = 0; i < len; i++) | |
a124fcda RH |
168 | { |
169 | rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0); | |
170 | ||
171 | /* When deleting code in bulk (e.g. removing many unreachable | |
172 | blocks) we can delete a label that's a target of the vector | |
173 | before deleting the vector itself. */ | |
174 | if (GET_CODE (label) != NOTE) | |
175 | LABEL_NUSES (label)--; | |
176 | } | |
ca6c03ca JH |
177 | } |
178 | ||
179 | return next; | |
180 | } | |
181 | ||
3dec4024 JH |
182 | /* Like delete_insn but also purge dead edges from BB. */ |
183 | rtx | |
184 | delete_insn_and_edges (insn) | |
185 | rtx insn; | |
186 | { | |
187 | rtx x; | |
188 | bool purge = false; | |
189 | ||
190 | if (basic_block_for_insn | |
191 | && INSN_P (insn) | |
192 | && (unsigned int)INSN_UID (insn) < basic_block_for_insn->num_elements | |
193 | && BLOCK_FOR_INSN (insn) | |
194 | && BLOCK_FOR_INSN (insn)->end == insn) | |
195 | purge = true; | |
196 | x = delete_insn (insn); | |
197 | if (purge) | |
198 | purge_dead_edges (BLOCK_FOR_INSN (insn)); | |
199 | return x; | |
200 | } | |
201 | ||
ca6c03ca JH |
202 | /* Unlink a chain of insns between START and FINISH, leaving notes |
203 | that must be paired. */ | |
204 | ||
205 | void | |
206 | delete_insn_chain (start, finish) | |
207 | rtx start, finish; | |
208 | { | |
ca6c03ca JH |
209 | rtx next; |
210 | ||
5f0d2358 RK |
211 | /* Unchain the insns one by one. It would be quicker to delete all of these |
212 | with a single unchaining, rather than one at a time, but we need to keep | |
213 | the NOTE's. */ | |
ca6c03ca JH |
214 | while (1) |
215 | { | |
216 | next = NEXT_INSN (start); | |
217 | if (GET_CODE (start) == NOTE && !can_delete_note_p (start)) | |
218 | ; | |
219 | else | |
220 | next = delete_insn (start); | |
221 | ||
222 | if (start == finish) | |
223 | break; | |
224 | start = next; | |
225 | } | |
226 | } | |
3dec4024 JH |
227 | |
228 | /* Like delete_insn but also purge dead edges from BB. */ | |
229 | void | |
230 | delete_insn_chain_and_edges (first, last) | |
231 | rtx first, last; | |
232 | { | |
233 | bool purge = false; | |
234 | ||
235 | if (basic_block_for_insn | |
236 | && INSN_P (last) | |
237 | && (unsigned int)INSN_UID (last) < basic_block_for_insn->num_elements | |
238 | && BLOCK_FOR_INSN (last) | |
239 | && BLOCK_FOR_INSN (last)->end == last) | |
240 | purge = true; | |
241 | delete_insn_chain (first, last); | |
242 | if (purge) | |
243 | purge_dead_edges (BLOCK_FOR_INSN (last)); | |
244 | } | |
ca6c03ca | 245 | \f |
5f0d2358 RK |
246 | /* Create a new basic block consisting of the instructions between HEAD and END |
247 | inclusive. This function is designed to allow fast BB construction - reuses | |
248 | the note and basic block struct in BB_NOTE, if any and do not grow | |
249 | BASIC_BLOCK chain and should be used directly only by CFG construction code. | |
250 | END can be NULL in to create new empty basic block before HEAD. Both END | |
251 | and HEAD can be NULL to create basic block at the end of INSN chain. */ | |
ca6c03ca JH |
252 | |
253 | basic_block | |
254 | create_basic_block_structure (index, head, end, bb_note) | |
255 | int index; | |
256 | rtx head, end, bb_note; | |
257 | { | |
258 | basic_block bb; | |
259 | ||
260 | if (bb_note | |
261 | && ! RTX_INTEGRATED_P (bb_note) | |
262 | && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL | |
263 | && bb->aux == NULL) | |
264 | { | |
265 | /* If we found an existing note, thread it back onto the chain. */ | |
266 | ||
267 | rtx after; | |
268 | ||
269 | if (GET_CODE (head) == CODE_LABEL) | |
270 | after = head; | |
271 | else | |
272 | { | |
273 | after = PREV_INSN (head); | |
274 | head = bb_note; | |
275 | } | |
276 | ||
277 | if (after != bb_note && NEXT_INSN (after) != bb_note) | |
278 | reorder_insns (bb_note, bb_note, after); | |
279 | } | |
280 | else | |
281 | { | |
282 | /* Otherwise we must create a note and a basic block structure. */ | |
283 | ||
284 | bb = alloc_block (); | |
285 | ||
286 | if (!head && !end) | |
5f0d2358 RK |
287 | head = end = bb_note |
288 | = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ()); | |
ca6c03ca JH |
289 | else if (GET_CODE (head) == CODE_LABEL && end) |
290 | { | |
291 | bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head); | |
292 | if (head == end) | |
293 | end = bb_note; | |
294 | } | |
295 | else | |
296 | { | |
297 | bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head); | |
298 | head = bb_note; | |
299 | if (!end) | |
300 | end = head; | |
301 | } | |
5f0d2358 | 302 | |
ca6c03ca JH |
303 | NOTE_BASIC_BLOCK (bb_note) = bb; |
304 | } | |
305 | ||
306 | /* Always include the bb note in the block. */ | |
307 | if (NEXT_INSN (end) == bb_note) | |
308 | end = bb_note; | |
309 | ||
310 | bb->head = head; | |
311 | bb->end = end; | |
312 | bb->index = index; | |
38c1593d | 313 | bb->flags = BB_NEW; |
ca6c03ca JH |
314 | BASIC_BLOCK (index) = bb; |
315 | if (basic_block_for_insn) | |
316 | update_bb_for_insn (bb); | |
317 | ||
318 | /* Tag the block so that we know it has been used when considering | |
319 | other basic block notes. */ | |
320 | bb->aux = bb; | |
321 | ||
322 | return bb; | |
323 | } | |
324 | ||
5f0d2358 RK |
325 | /* Create new basic block consisting of instructions in between HEAD and END |
326 | and place it to the BB chain at position INDEX. END can be NULL in to | |
327 | create new empty basic block before HEAD. Both END and HEAD can be NULL to | |
328 | create basic block at the end of INSN chain. */ | |
ca6c03ca JH |
329 | |
330 | basic_block | |
331 | create_basic_block (index, head, end) | |
332 | int index; | |
333 | rtx head, end; | |
334 | { | |
335 | basic_block bb; | |
336 | int i; | |
337 | ||
338 | /* Place the new block just after the block being split. */ | |
339 | VARRAY_GROW (basic_block_info, ++n_basic_blocks); | |
340 | ||
341 | /* Some parts of the compiler expect blocks to be number in | |
342 | sequential order so insert the new block immediately after the | |
343 | block being split.. */ | |
344 | for (i = n_basic_blocks - 1; i > index; --i) | |
345 | { | |
346 | basic_block tmp = BASIC_BLOCK (i - 1); | |
5f0d2358 | 347 | |
ca6c03ca JH |
348 | BASIC_BLOCK (i) = tmp; |
349 | tmp->index = i; | |
350 | } | |
351 | ||
352 | bb = create_basic_block_structure (index, head, end, NULL); | |
353 | bb->aux = NULL; | |
354 | return bb; | |
355 | } | |
356 | \f | |
357 | /* Delete the insns in a (non-live) block. We physically delete every | |
358 | non-deleted-note insn, and update the flow graph appropriately. | |
359 | ||
360 | Return nonzero if we deleted an exception handler. */ | |
361 | ||
362 | /* ??? Preserving all such notes strikes me as wrong. It would be nice | |
363 | to post-process the stream to remove empty blocks, loops, ranges, etc. */ | |
364 | ||
365 | int | |
6a58eee9 | 366 | flow_delete_block_noexpunge (b) |
ca6c03ca JH |
367 | basic_block b; |
368 | { | |
369 | int deleted_handler = 0; | |
370 | rtx insn, end, tmp; | |
371 | ||
372 | /* If the head of this block is a CODE_LABEL, then it might be the | |
373 | label for an exception handler which can't be reached. | |
374 | ||
375 | We need to remove the label from the exception_handler_label list | |
376 | and remove the associated NOTE_INSN_EH_REGION_BEG and | |
377 | NOTE_INSN_EH_REGION_END notes. */ | |
378 | ||
969d70ca JH |
379 | /* Get rid of all NOTE_INSN_PREDICTIONs hanging before the block. */ |
380 | ||
381 | for (insn = PREV_INSN (b->head); insn; insn = PREV_INSN (insn)) | |
382 | { | |
383 | if (GET_CODE (insn) != NOTE) | |
384 | break; | |
385 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_PREDICTION) | |
386 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
387 | } | |
388 | ||
ca6c03ca JH |
389 | insn = b->head; |
390 | ||
56d44285 | 391 | never_reached_warning (insn, b->end); |
ca6c03ca JH |
392 | |
393 | if (GET_CODE (insn) == CODE_LABEL) | |
394 | maybe_remove_eh_handler (insn); | |
395 | ||
396 | /* Include any jump table following the basic block. */ | |
397 | end = b->end; | |
398 | if (GET_CODE (end) == JUMP_INSN | |
399 | && (tmp = JUMP_LABEL (end)) != NULL_RTX | |
400 | && (tmp = NEXT_INSN (tmp)) != NULL_RTX | |
401 | && GET_CODE (tmp) == JUMP_INSN | |
402 | && (GET_CODE (PATTERN (tmp)) == ADDR_VEC | |
403 | || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC)) | |
404 | end = tmp; | |
405 | ||
406 | /* Include any barrier that may follow the basic block. */ | |
407 | tmp = next_nonnote_insn (end); | |
408 | if (tmp && GET_CODE (tmp) == BARRIER) | |
409 | end = tmp; | |
410 | ||
411 | /* Selectively delete the entire chain. */ | |
412 | b->head = NULL; | |
413 | delete_insn_chain (insn, end); | |
414 | ||
415 | /* Remove the edges into and out of this block. Note that there may | |
416 | indeed be edges in, if we are removing an unreachable loop. */ | |
417 | while (b->pred != NULL) | |
418 | remove_edge (b->pred); | |
419 | while (b->succ != NULL) | |
420 | remove_edge (b->succ); | |
421 | ||
422 | b->pred = NULL; | |
423 | b->succ = NULL; | |
424 | ||
6a58eee9 RH |
425 | return deleted_handler; |
426 | } | |
427 | ||
428 | int | |
429 | flow_delete_block (b) | |
430 | basic_block b; | |
431 | { | |
432 | int deleted_handler = flow_delete_block_noexpunge (b); | |
433 | ||
ca6c03ca JH |
434 | /* Remove the basic block from the array, and compact behind it. */ |
435 | expunge_block (b); | |
436 | ||
437 | return deleted_handler; | |
438 | } | |
439 | \f | |
440 | /* Records the basic block struct in BB_FOR_INSN, for every instruction | |
441 | indexed by INSN_UID. MAX is the size of the array. */ | |
442 | ||
443 | void | |
444 | compute_bb_for_insn (max) | |
445 | int max; | |
446 | { | |
447 | int i; | |
448 | ||
449 | if (basic_block_for_insn) | |
450 | VARRAY_FREE (basic_block_for_insn); | |
5f0d2358 | 451 | |
ca6c03ca JH |
452 | VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn"); |
453 | ||
454 | for (i = 0; i < n_basic_blocks; ++i) | |
455 | { | |
456 | basic_block bb = BASIC_BLOCK (i); | |
5f0d2358 RK |
457 | rtx end = bb->end; |
458 | rtx insn; | |
ca6c03ca | 459 | |
5f0d2358 | 460 | for (insn = bb->head; ; insn = NEXT_INSN (insn)) |
ca6c03ca | 461 | { |
5f0d2358 RK |
462 | if (INSN_UID (insn) < max) |
463 | VARRAY_BB (basic_block_for_insn, INSN_UID (insn)) = bb; | |
464 | ||
ca6c03ca JH |
465 | if (insn == end) |
466 | break; | |
ca6c03ca JH |
467 | } |
468 | } | |
469 | } | |
470 | ||
471 | /* Release the basic_block_for_insn array. */ | |
472 | ||
473 | void | |
474 | free_bb_for_insn () | |
475 | { | |
476 | if (basic_block_for_insn) | |
477 | VARRAY_FREE (basic_block_for_insn); | |
5f0d2358 | 478 | |
ca6c03ca JH |
479 | basic_block_for_insn = 0; |
480 | } | |
481 | ||
482 | /* Update insns block within BB. */ | |
483 | ||
484 | void | |
485 | update_bb_for_insn (bb) | |
486 | basic_block bb; | |
487 | { | |
488 | rtx insn; | |
489 | ||
490 | if (! basic_block_for_insn) | |
491 | return; | |
492 | ||
493 | for (insn = bb->head; ; insn = NEXT_INSN (insn)) | |
494 | { | |
495 | set_block_for_insn (insn, bb); | |
ca6c03ca JH |
496 | if (insn == bb->end) |
497 | break; | |
498 | } | |
499 | } | |
500 | ||
501 | /* Record INSN's block as BB. */ | |
502 | ||
503 | void | |
504 | set_block_for_insn (insn, bb) | |
505 | rtx insn; | |
506 | basic_block bb; | |
507 | { | |
508 | size_t uid = INSN_UID (insn); | |
5f0d2358 | 509 | |
ca6c03ca JH |
510 | if (uid >= basic_block_for_insn->num_elements) |
511 | { | |
ca6c03ca | 512 | /* Add one-eighth the size so we don't keep calling xrealloc. */ |
5f0d2358 | 513 | size_t new_size = uid + (uid + 7) / 8; |
ca6c03ca JH |
514 | |
515 | VARRAY_GROW (basic_block_for_insn, new_size); | |
516 | } | |
5f0d2358 | 517 | |
ca6c03ca JH |
518 | VARRAY_BB (basic_block_for_insn, uid) = bb; |
519 | } | |
520 | \f | |
521 | /* Split a block BB after insn INSN creating a new fallthru edge. | |
522 | Return the new edge. Note that to keep other parts of the compiler happy, | |
523 | this function renumbers all the basic blocks so that the new | |
524 | one has a number one greater than the block split. */ | |
525 | ||
526 | edge | |
527 | split_block (bb, insn) | |
528 | basic_block bb; | |
529 | rtx insn; | |
530 | { | |
531 | basic_block new_bb; | |
532 | edge new_edge; | |
533 | edge e; | |
534 | ||
535 | /* There is no point splitting the block after its end. */ | |
536 | if (bb->end == insn) | |
537 | return 0; | |
538 | ||
539 | /* Create the new basic block. */ | |
540 | new_bb = create_basic_block (bb->index + 1, NEXT_INSN (insn), bb->end); | |
541 | new_bb->count = bb->count; | |
542 | new_bb->frequency = bb->frequency; | |
543 | new_bb->loop_depth = bb->loop_depth; | |
544 | bb->end = insn; | |
545 | ||
546 | /* Redirect the outgoing edges. */ | |
547 | new_bb->succ = bb->succ; | |
548 | bb->succ = NULL; | |
549 | for (e = new_bb->succ; e; e = e->succ_next) | |
550 | e->src = new_bb; | |
551 | ||
552 | new_edge = make_single_succ_edge (bb, new_bb, EDGE_FALLTHRU); | |
553 | ||
554 | if (bb->global_live_at_start) | |
555 | { | |
556 | new_bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack); | |
557 | new_bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack); | |
558 | COPY_REG_SET (new_bb->global_live_at_end, bb->global_live_at_end); | |
559 | ||
560 | /* We now have to calculate which registers are live at the end | |
561 | of the split basic block and at the start of the new basic | |
562 | block. Start with those registers that are known to be live | |
563 | at the end of the original basic block and get | |
564 | propagate_block to determine which registers are live. */ | |
565 | COPY_REG_SET (new_bb->global_live_at_start, bb->global_live_at_end); | |
566 | propagate_block (new_bb, new_bb->global_live_at_start, NULL, NULL, 0); | |
567 | COPY_REG_SET (bb->global_live_at_end, | |
568 | new_bb->global_live_at_start); | |
0a2ed1f1 JH |
569 | #ifdef HAVE_conditional_execution |
570 | /* In the presence of conditional execution we are not able to update | |
571 | liveness precisely. */ | |
572 | if (reload_completed) | |
573 | { | |
574 | bb->flags |= BB_DIRTY; | |
575 | new_bb->flags |= BB_DIRTY; | |
576 | } | |
577 | #endif | |
ca6c03ca JH |
578 | } |
579 | ||
580 | return new_edge; | |
581 | } | |
582 | ||
583 | /* Blocks A and B are to be merged into a single block A. The insns | |
584 | are already contiguous, hence `nomove'. */ | |
585 | ||
586 | void | |
587 | merge_blocks_nomove (a, b) | |
588 | basic_block a, b; | |
589 | { | |
5f0d2358 | 590 | rtx b_head = b->head, b_end = b->end, a_end = a->end; |
ca6c03ca JH |
591 | rtx del_first = NULL_RTX, del_last = NULL_RTX; |
592 | int b_empty = 0; | |
5f0d2358 | 593 | edge e; |
ca6c03ca JH |
594 | |
595 | /* If there was a CODE_LABEL beginning B, delete it. */ | |
ca6c03ca JH |
596 | if (GET_CODE (b_head) == CODE_LABEL) |
597 | { | |
598 | /* Detect basic blocks with nothing but a label. This can happen | |
599 | in particular at the end of a function. */ | |
600 | if (b_head == b_end) | |
601 | b_empty = 1; | |
5f0d2358 | 602 | |
ca6c03ca JH |
603 | del_first = del_last = b_head; |
604 | b_head = NEXT_INSN (b_head); | |
605 | } | |
606 | ||
5f0d2358 RK |
607 | /* Delete the basic block note and handle blocks containing just that |
608 | note. */ | |
ca6c03ca JH |
609 | if (NOTE_INSN_BASIC_BLOCK_P (b_head)) |
610 | { | |
611 | if (b_head == b_end) | |
612 | b_empty = 1; | |
613 | if (! del_last) | |
614 | del_first = b_head; | |
5f0d2358 | 615 | |
ca6c03ca JH |
616 | del_last = b_head; |
617 | b_head = NEXT_INSN (b_head); | |
618 | } | |
619 | ||
620 | /* If there was a jump out of A, delete it. */ | |
ca6c03ca JH |
621 | if (GET_CODE (a_end) == JUMP_INSN) |
622 | { | |
623 | rtx prev; | |
624 | ||
625 | for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev)) | |
626 | if (GET_CODE (prev) != NOTE | |
627 | || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK | |
628 | || prev == a->head) | |
629 | break; | |
630 | ||
631 | del_first = a_end; | |
632 | ||
633 | #ifdef HAVE_cc0 | |
634 | /* If this was a conditional jump, we need to also delete | |
635 | the insn that set cc0. */ | |
636 | if (only_sets_cc0_p (prev)) | |
637 | { | |
638 | rtx tmp = prev; | |
5f0d2358 | 639 | |
ca6c03ca JH |
640 | prev = prev_nonnote_insn (prev); |
641 | if (!prev) | |
642 | prev = a->head; | |
643 | del_first = tmp; | |
644 | } | |
645 | #endif | |
646 | ||
647 | a_end = PREV_INSN (del_first); | |
648 | } | |
649 | else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER) | |
650 | del_first = NEXT_INSN (a_end); | |
651 | ||
652 | /* Normally there should only be one successor of A and that is B, but | |
653 | partway though the merge of blocks for conditional_execution we'll | |
654 | be merging a TEST block with THEN and ELSE successors. Free the | |
655 | whole lot of them and hope the caller knows what they're doing. */ | |
656 | while (a->succ) | |
657 | remove_edge (a->succ); | |
658 | ||
659 | /* Adjust the edges out of B for the new owner. */ | |
660 | for (e = b->succ; e; e = e->succ_next) | |
661 | e->src = a; | |
662 | a->succ = b->succ; | |
38c1593d | 663 | a->flags |= b->flags; |
ca6c03ca JH |
664 | |
665 | /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */ | |
666 | b->pred = b->succ = NULL; | |
7dddfb65 | 667 | a->global_live_at_end = b->global_live_at_end; |
ca6c03ca JH |
668 | |
669 | expunge_block (b); | |
670 | ||
671 | /* Delete everything marked above as well as crap that might be | |
672 | hanging out between the two blocks. */ | |
673 | delete_insn_chain (del_first, del_last); | |
674 | ||
675 | /* Reassociate the insns of B with A. */ | |
676 | if (!b_empty) | |
677 | { | |
ca6c03ca JH |
678 | if (basic_block_for_insn) |
679 | { | |
5f0d2358 RK |
680 | rtx x; |
681 | ||
682 | for (x = a_end; x != b_end; x = NEXT_INSN (x)) | |
e27a4eaf | 683 | set_block_for_insn (x, a); |
5f0d2358 | 684 | |
e27a4eaf | 685 | set_block_for_insn (b_end, a); |
ca6c03ca | 686 | } |
5f0d2358 | 687 | |
ca6c03ca JH |
688 | a_end = b_end; |
689 | } | |
5f0d2358 | 690 | |
ca6c03ca JH |
691 | a->end = a_end; |
692 | } | |
693 | \f | |
5f0d2358 RK |
694 | /* Return the label in the head of basic block BLOCK. Create one if it doesn't |
695 | exist. */ | |
ca6c03ca JH |
696 | |
697 | rtx | |
698 | block_label (block) | |
699 | basic_block block; | |
700 | { | |
701 | if (block == EXIT_BLOCK_PTR) | |
702 | return NULL_RTX; | |
5f0d2358 | 703 | |
ca6c03ca JH |
704 | if (GET_CODE (block->head) != CODE_LABEL) |
705 | { | |
706 | block->head = emit_label_before (gen_label_rtx (), block->head); | |
707 | if (basic_block_for_insn) | |
708 | set_block_for_insn (block->head, block); | |
709 | } | |
5f0d2358 | 710 | |
ca6c03ca JH |
711 | return block->head; |
712 | } | |
713 | ||
714 | /* Attempt to perform edge redirection by replacing possibly complex jump | |
5f0d2358 RK |
715 | instruction by unconditional jump or removing jump completely. This can |
716 | apply only if all edges now point to the same block. The parameters and | |
717 | return values are equivalent to redirect_edge_and_branch. */ | |
ca6c03ca JH |
718 | |
719 | static bool | |
720 | try_redirect_by_replacing_jump (e, target) | |
721 | edge e; | |
722 | basic_block target; | |
723 | { | |
724 | basic_block src = e->src; | |
725 | rtx insn = src->end, kill_from; | |
726 | edge tmp; | |
1b6763cf | 727 | rtx set, table; |
ca6c03ca JH |
728 | int fallthru = 0; |
729 | ||
730 | /* Verify that all targets will be TARGET. */ | |
731 | for (tmp = src->succ; tmp; tmp = tmp->succ_next) | |
732 | if (tmp->dest != target && tmp != e) | |
733 | break; | |
5f0d2358 | 734 | |
ca6c03ca JH |
735 | if (tmp || !onlyjump_p (insn)) |
736 | return false; | |
1b6763cf JH |
737 | if (reload_completed && JUMP_LABEL (insn) |
738 | && (table = NEXT_INSN (JUMP_LABEL (insn))) != NULL_RTX | |
739 | && GET_CODE (table) == JUMP_INSN | |
740 | && (GET_CODE (PATTERN (table)) == ADDR_VEC | |
741 | || GET_CODE (PATTERN (table)) == ADDR_DIFF_VEC)) | |
742 | return false; | |
ca6c03ca JH |
743 | |
744 | /* Avoid removing branch with side effects. */ | |
745 | set = single_set (insn); | |
746 | if (!set || side_effects_p (set)) | |
747 | return false; | |
748 | ||
749 | /* In case we zap a conditional jump, we'll need to kill | |
750 | the cc0 setter too. */ | |
751 | kill_from = insn; | |
752 | #ifdef HAVE_cc0 | |
753 | if (reg_mentioned_p (cc0_rtx, PATTERN (insn))) | |
754 | kill_from = PREV_INSN (insn); | |
755 | #endif | |
756 | ||
757 | /* See if we can create the fallthru edge. */ | |
758 | if (can_fallthru (src, target)) | |
759 | { | |
760 | if (rtl_dump_file) | |
761 | fprintf (rtl_dump_file, "Removing jump %i.\n", INSN_UID (insn)); | |
762 | fallthru = 1; | |
763 | ||
eaec9b3d | 764 | /* Selectively unlink whole insn chain. */ |
ca6c03ca JH |
765 | delete_insn_chain (kill_from, PREV_INSN (target->head)); |
766 | } | |
5f0d2358 | 767 | |
ca6c03ca JH |
768 | /* If this already is simplejump, redirect it. */ |
769 | else if (simplejump_p (insn)) | |
770 | { | |
771 | if (e->dest == target) | |
772 | return false; | |
773 | if (rtl_dump_file) | |
774 | fprintf (rtl_dump_file, "Redirecting jump %i from %i to %i.\n", | |
775 | INSN_UID (insn), e->dest->index, target->index); | |
6ee3c8e4 JJ |
776 | if (!redirect_jump (insn, block_label (target), 0)) |
777 | { | |
778 | if (target == EXIT_BLOCK_PTR) | |
779 | return false; | |
780 | abort (); | |
781 | } | |
ca6c03ca | 782 | } |
5f0d2358 | 783 | |
6ee3c8e4 JJ |
784 | /* Cannot do anything for target exit block. */ |
785 | else if (target == EXIT_BLOCK_PTR) | |
786 | return false; | |
787 | ||
ca6c03ca JH |
788 | /* Or replace possibly complicated jump insn by simple jump insn. */ |
789 | else | |
790 | { | |
791 | rtx target_label = block_label (target); | |
5b1cacd8 | 792 | rtx barrier, tmp; |
ca6c03ca | 793 | |
09eb1aab | 794 | emit_jump_insn_after (gen_jump (target_label), insn); |
ca6c03ca JH |
795 | JUMP_LABEL (src->end) = target_label; |
796 | LABEL_NUSES (target_label)++; | |
797 | if (rtl_dump_file) | |
798 | fprintf (rtl_dump_file, "Replacing insn %i by jump %i\n", | |
799 | INSN_UID (insn), INSN_UID (src->end)); | |
800 | ||
5b1cacd8 | 801 | |
ca6c03ca JH |
802 | delete_insn_chain (kill_from, insn); |
803 | ||
5b1cacd8 JL |
804 | /* Recognize a tablejump that we are converting to a |
805 | simple jump and remove its associated CODE_LABEL | |
806 | and ADDR_VEC or ADDR_DIFF_VEC. */ | |
807 | if ((tmp = JUMP_LABEL (insn)) != NULL_RTX | |
808 | && (tmp = NEXT_INSN (tmp)) != NULL_RTX | |
809 | && GET_CODE (tmp) == JUMP_INSN | |
810 | && (GET_CODE (PATTERN (tmp)) == ADDR_VEC | |
811 | || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC)) | |
812 | { | |
813 | delete_insn_chain (JUMP_LABEL (insn), tmp); | |
814 | } | |
815 | ||
ca6c03ca JH |
816 | barrier = next_nonnote_insn (src->end); |
817 | if (!barrier || GET_CODE (barrier) != BARRIER) | |
818 | emit_barrier_after (src->end); | |
819 | } | |
820 | ||
821 | /* Keep only one edge out and set proper flags. */ | |
822 | while (src->succ->succ_next) | |
823 | remove_edge (src->succ); | |
824 | e = src->succ; | |
825 | if (fallthru) | |
826 | e->flags = EDGE_FALLTHRU; | |
827 | else | |
828 | e->flags = 0; | |
5f0d2358 | 829 | |
ca6c03ca JH |
830 | e->probability = REG_BR_PROB_BASE; |
831 | e->count = src->count; | |
832 | ||
833 | /* We don't want a block to end on a line-number note since that has | |
834 | the potential of changing the code between -g and not -g. */ | |
835 | while (GET_CODE (e->src->end) == NOTE | |
836 | && NOTE_LINE_NUMBER (e->src->end) >= 0) | |
837 | delete_insn (e->src->end); | |
838 | ||
839 | if (e->dest != target) | |
840 | redirect_edge_succ (e, target); | |
5f0d2358 | 841 | |
ca6c03ca JH |
842 | return true; |
843 | } | |
844 | ||
845 | /* Return last loop_beg note appearing after INSN, before start of next | |
846 | basic block. Return INSN if there are no such notes. | |
847 | ||
5f0d2358 RK |
848 | When emitting jump to redirect an fallthru edge, it should always appear |
849 | after the LOOP_BEG notes, as loop optimizer expect loop to either start by | |
850 | fallthru edge or jump following the LOOP_BEG note jumping to the loop exit | |
851 | test. */ | |
ca6c03ca JH |
852 | |
853 | static rtx | |
854 | last_loop_beg_note (insn) | |
855 | rtx insn; | |
856 | { | |
857 | rtx last = insn; | |
5f0d2358 RK |
858 | |
859 | for (insn = NEXT_INSN (insn); insn && GET_CODE (insn) == NOTE | |
860 | && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK; | |
861 | insn = NEXT_INSN (insn)) | |
862 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) | |
863 | last = insn; | |
864 | ||
ca6c03ca JH |
865 | return last; |
866 | } | |
867 | ||
5f0d2358 RK |
868 | /* Attempt to change code to redirect edge E to TARGET. Don't do that on |
869 | expense of adding new instructions or reordering basic blocks. | |
ca6c03ca | 870 | |
5f0d2358 RK |
871 | Function can be also called with edge destination equivalent to the TARGET. |
872 | Then it should try the simplifications and do nothing if none is possible. | |
ca6c03ca | 873 | |
5f0d2358 RK |
874 | Return true if transformation succeeded. We still return false in case E |
875 | already destinated TARGET and we didn't managed to simplify instruction | |
ca6c03ca JH |
876 | stream. */ |
877 | ||
878 | bool | |
879 | redirect_edge_and_branch (e, target) | |
880 | edge e; | |
881 | basic_block target; | |
882 | { | |
883 | rtx tmp; | |
884 | rtx old_label = e->dest->head; | |
885 | basic_block src = e->src; | |
886 | rtx insn = src->end; | |
887 | ||
25b44be5 | 888 | if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) |
ca6c03ca JH |
889 | return false; |
890 | ||
891 | if (try_redirect_by_replacing_jump (e, target)) | |
892 | return true; | |
5f0d2358 | 893 | |
ca6c03ca JH |
894 | /* Do this fast path late, as we want above code to simplify for cases |
895 | where called on single edge leaving basic block containing nontrivial | |
896 | jump insn. */ | |
897 | else if (e->dest == target) | |
898 | return false; | |
899 | ||
900 | /* We can only redirect non-fallthru edges of jump insn. */ | |
901 | if (e->flags & EDGE_FALLTHRU) | |
902 | return false; | |
5f0d2358 | 903 | else if (GET_CODE (insn) != JUMP_INSN) |
ca6c03ca JH |
904 | return false; |
905 | ||
906 | /* Recognize a tablejump and adjust all matching cases. */ | |
907 | if ((tmp = JUMP_LABEL (insn)) != NULL_RTX | |
908 | && (tmp = NEXT_INSN (tmp)) != NULL_RTX | |
909 | && GET_CODE (tmp) == JUMP_INSN | |
910 | && (GET_CODE (PATTERN (tmp)) == ADDR_VEC | |
911 | || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC)) | |
912 | { | |
913 | rtvec vec; | |
914 | int j; | |
915 | rtx new_label = block_label (target); | |
916 | ||
6ee3c8e4 JJ |
917 | if (target == EXIT_BLOCK_PTR) |
918 | return false; | |
ca6c03ca JH |
919 | if (GET_CODE (PATTERN (tmp)) == ADDR_VEC) |
920 | vec = XVEC (PATTERN (tmp), 0); | |
921 | else | |
922 | vec = XVEC (PATTERN (tmp), 1); | |
923 | ||
924 | for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) | |
925 | if (XEXP (RTVEC_ELT (vec, j), 0) == old_label) | |
926 | { | |
927 | RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label); | |
928 | --LABEL_NUSES (old_label); | |
929 | ++LABEL_NUSES (new_label); | |
930 | } | |
931 | ||
932 | /* Handle casesi dispatch insns */ | |
933 | if ((tmp = single_set (insn)) != NULL | |
934 | && SET_DEST (tmp) == pc_rtx | |
935 | && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE | |
936 | && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF | |
937 | && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label) | |
938 | { | |
939 | XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode, | |
940 | new_label); | |
941 | --LABEL_NUSES (old_label); | |
942 | ++LABEL_NUSES (new_label); | |
943 | } | |
944 | } | |
945 | else | |
946 | { | |
947 | /* ?? We may play the games with moving the named labels from | |
948 | one basic block to the other in case only one computed_jump is | |
949 | available. */ | |
5f0d2358 RK |
950 | if (computed_jump_p (insn) |
951 | /* A return instruction can't be redirected. */ | |
952 | || returnjump_p (insn)) | |
ca6c03ca JH |
953 | return false; |
954 | ||
955 | /* If the insn doesn't go where we think, we're confused. */ | |
6ee3c8e4 | 956 | if (JUMP_LABEL (insn) != old_label) |
a3623c48 | 957 | abort (); |
6ee3c8e4 JJ |
958 | |
959 | /* If the substitution doesn't succeed, die. This can happen | |
960 | if the back end emitted unrecognizable instructions or if | |
961 | target is exit block on some arches. */ | |
962 | if (!redirect_jump (insn, block_label (target), 0)) | |
963 | { | |
964 | if (target == EXIT_BLOCK_PTR) | |
965 | return false; | |
966 | abort (); | |
967 | } | |
ca6c03ca JH |
968 | } |
969 | ||
970 | if (rtl_dump_file) | |
971 | fprintf (rtl_dump_file, "Edge %i->%i redirected to %i\n", | |
972 | e->src->index, e->dest->index, target->index); | |
5f0d2358 | 973 | |
ca6c03ca JH |
974 | if (e->dest != target) |
975 | redirect_edge_succ_nodup (e, target); | |
5f0d2358 | 976 | |
ca6c03ca JH |
977 | return true; |
978 | } | |
979 | ||
4fe9b91c | 980 | /* Like force_nonfallthru below, but additionally performs redirection |
ca6c03ca JH |
981 | Used by redirect_edge_and_branch_force. */ |
982 | ||
983 | static basic_block | |
984 | force_nonfallthru_and_redirect (e, target) | |
985 | edge e; | |
986 | basic_block target; | |
987 | { | |
988 | basic_block jump_block, new_bb = NULL; | |
989 | rtx note; | |
990 | edge new_edge; | |
991 | ||
992 | if (e->flags & EDGE_ABNORMAL) | |
993 | abort (); | |
5f0d2358 | 994 | else if (!(e->flags & EDGE_FALLTHRU)) |
ca6c03ca | 995 | abort (); |
24c545ff BS |
996 | else if (e->src == ENTRY_BLOCK_PTR) |
997 | { | |
998 | /* We can't redirect the entry block. Create an empty block at the | |
999 | start of the function which we use to add the new jump. */ | |
1000 | edge *pe1; | |
1001 | basic_block bb = create_basic_block (0, e->dest->head, NULL); | |
1002 | ||
1003 | /* Change the existing edge's source to be the new block, and add | |
1004 | a new edge from the entry block to the new block. */ | |
1005 | e->src = bb; | |
1006 | for (pe1 = &ENTRY_BLOCK_PTR->succ; *pe1; pe1 = &(*pe1)->succ_next) | |
1007 | if (*pe1 == e) | |
1008 | { | |
1009 | *pe1 = e->succ_next; | |
1010 | break; | |
1011 | } | |
1012 | e->succ_next = 0; | |
1013 | bb->succ = e; | |
1014 | make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU); | |
1015 | } | |
1016 | ||
1017 | if (e->src->succ->succ_next) | |
ca6c03ca JH |
1018 | { |
1019 | /* Create the new structures. */ | |
1020 | note = last_loop_beg_note (e->src->end); | |
5f0d2358 RK |
1021 | jump_block |
1022 | = create_basic_block (e->src->index + 1, NEXT_INSN (note), NULL); | |
ca6c03ca JH |
1023 | jump_block->count = e->count; |
1024 | jump_block->frequency = EDGE_FREQUENCY (e); | |
1025 | jump_block->loop_depth = target->loop_depth; | |
1026 | ||
1027 | if (target->global_live_at_start) | |
1028 | { | |
5f0d2358 RK |
1029 | jump_block->global_live_at_start |
1030 | = OBSTACK_ALLOC_REG_SET (&flow_obstack); | |
1031 | jump_block->global_live_at_end | |
1032 | = OBSTACK_ALLOC_REG_SET (&flow_obstack); | |
ca6c03ca JH |
1033 | COPY_REG_SET (jump_block->global_live_at_start, |
1034 | target->global_live_at_start); | |
1035 | COPY_REG_SET (jump_block->global_live_at_end, | |
1036 | target->global_live_at_start); | |
1037 | } | |
1038 | ||
1039 | /* Wire edge in. */ | |
1040 | new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU); | |
1041 | new_edge->probability = e->probability; | |
1042 | new_edge->count = e->count; | |
1043 | ||
1044 | /* Redirect old edge. */ | |
1045 | redirect_edge_pred (e, jump_block); | |
1046 | e->probability = REG_BR_PROB_BASE; | |
1047 | ||
1048 | new_bb = jump_block; | |
1049 | } | |
1050 | else | |
1051 | jump_block = e->src; | |
5f0d2358 | 1052 | |
ca6c03ca JH |
1053 | e->flags &= ~EDGE_FALLTHRU; |
1054 | if (target == EXIT_BLOCK_PTR) | |
1055 | { | |
1056 | if (HAVE_return) | |
1057 | emit_jump_insn_after (gen_return (), jump_block->end); | |
1058 | else | |
1059 | abort (); | |
1060 | } | |
1061 | else | |
1062 | { | |
1063 | rtx label = block_label (target); | |
1064 | emit_jump_insn_after (gen_jump (label), jump_block->end); | |
1065 | JUMP_LABEL (jump_block->end) = label; | |
1066 | LABEL_NUSES (label)++; | |
1067 | } | |
5f0d2358 | 1068 | |
ca6c03ca JH |
1069 | emit_barrier_after (jump_block->end); |
1070 | redirect_edge_succ_nodup (e, target); | |
1071 | ||
1072 | return new_bb; | |
1073 | } | |
1074 | ||
1075 | /* Edge E is assumed to be fallthru edge. Emit needed jump instruction | |
1076 | (and possibly create new basic block) to make edge non-fallthru. | |
1077 | Return newly created BB or NULL if none. */ | |
5f0d2358 | 1078 | |
ca6c03ca JH |
1079 | basic_block |
1080 | force_nonfallthru (e) | |
1081 | edge e; | |
1082 | { | |
1083 | return force_nonfallthru_and_redirect (e, e->dest); | |
1084 | } | |
1085 | ||
1086 | /* Redirect edge even at the expense of creating new jump insn or | |
1087 | basic block. Return new basic block if created, NULL otherwise. | |
eaec9b3d | 1088 | Abort if conversion is impossible. */ |
ca6c03ca JH |
1089 | |
1090 | basic_block | |
1091 | redirect_edge_and_branch_force (e, target) | |
1092 | edge e; | |
1093 | basic_block target; | |
1094 | { | |
5f0d2358 RK |
1095 | if (redirect_edge_and_branch (e, target) |
1096 | || e->dest == target) | |
ca6c03ca JH |
1097 | return NULL; |
1098 | ||
1099 | /* In case the edge redirection failed, try to force it to be non-fallthru | |
1100 | and redirect newly created simplejump. */ | |
5f0d2358 | 1101 | return force_nonfallthru_and_redirect (e, target); |
ca6c03ca JH |
1102 | } |
1103 | ||
1104 | /* The given edge should potentially be a fallthru edge. If that is in | |
1105 | fact true, delete the jump and barriers that are in the way. */ | |
1106 | ||
1107 | void | |
1108 | tidy_fallthru_edge (e, b, c) | |
1109 | edge e; | |
1110 | basic_block b, c; | |
1111 | { | |
1112 | rtx q; | |
1113 | ||
1114 | /* ??? In a late-running flow pass, other folks may have deleted basic | |
1115 | blocks by nopping out blocks, leaving multiple BARRIERs between here | |
1116 | and the target label. They ought to be chastized and fixed. | |
1117 | ||
1118 | We can also wind up with a sequence of undeletable labels between | |
1119 | one block and the next. | |
1120 | ||
1121 | So search through a sequence of barriers, labels, and notes for | |
1122 | the head of block C and assert that we really do fall through. */ | |
1123 | ||
9c0a0632 RH |
1124 | for (q = NEXT_INSN (b->end); q != c->head; q = NEXT_INSN (q)) |
1125 | if (INSN_P (q)) | |
1126 | return; | |
ca6c03ca JH |
1127 | |
1128 | /* Remove what will soon cease being the jump insn from the source block. | |
1129 | If block B consisted only of this single jump, turn it into a deleted | |
1130 | note. */ | |
1131 | q = b->end; | |
1132 | if (GET_CODE (q) == JUMP_INSN | |
1133 | && onlyjump_p (q) | |
1134 | && (any_uncondjump_p (q) | |
1135 | || (b->succ == e && e->succ_next == NULL))) | |
1136 | { | |
1137 | #ifdef HAVE_cc0 | |
1138 | /* If this was a conditional jump, we need to also delete | |
1139 | the insn that set cc0. */ | |
1140 | if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q))) | |
1141 | q = PREV_INSN (q); | |
1142 | #endif | |
1143 | ||
1144 | q = PREV_INSN (q); | |
1145 | ||
1146 | /* We don't want a block to end on a line-number note since that has | |
1147 | the potential of changing the code between -g and not -g. */ | |
1148 | while (GET_CODE (q) == NOTE && NOTE_LINE_NUMBER (q) >= 0) | |
1149 | q = PREV_INSN (q); | |
1150 | } | |
1151 | ||
1152 | /* Selectively unlink the sequence. */ | |
1153 | if (q != PREV_INSN (c->head)) | |
1154 | delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head)); | |
1155 | ||
1156 | e->flags |= EDGE_FALLTHRU; | |
1157 | } | |
1158 | ||
1159 | /* Fix up edges that now fall through, or rather should now fall through | |
1160 | but previously required a jump around now deleted blocks. Simplify | |
1161 | the search by only examining blocks numerically adjacent, since this | |
1162 | is how find_basic_blocks created them. */ | |
1163 | ||
1164 | void | |
1165 | tidy_fallthru_edges () | |
1166 | { | |
1167 | int i; | |
1168 | ||
5f0d2358 | 1169 | for (i = 1; i < n_basic_blocks; i++) |
ca6c03ca JH |
1170 | { |
1171 | basic_block b = BASIC_BLOCK (i - 1); | |
1172 | basic_block c = BASIC_BLOCK (i); | |
1173 | edge s; | |
1174 | ||
1175 | /* We care about simple conditional or unconditional jumps with | |
1176 | a single successor. | |
1177 | ||
1178 | If we had a conditional branch to the next instruction when | |
1179 | find_basic_blocks was called, then there will only be one | |
1180 | out edge for the block which ended with the conditional | |
1181 | branch (since we do not create duplicate edges). | |
1182 | ||
1183 | Furthermore, the edge will be marked as a fallthru because we | |
1184 | merge the flags for the duplicate edges. So we do not want to | |
1185 | check that the edge is not a FALLTHRU edge. */ | |
5f0d2358 | 1186 | |
ca6c03ca JH |
1187 | if ((s = b->succ) != NULL |
1188 | && ! (s->flags & EDGE_COMPLEX) | |
1189 | && s->succ_next == NULL | |
1190 | && s->dest == c | |
1191 | /* If the jump insn has side effects, we can't tidy the edge. */ | |
1192 | && (GET_CODE (b->end) != JUMP_INSN | |
1193 | || onlyjump_p (b->end))) | |
1194 | tidy_fallthru_edge (s, b, c); | |
1195 | } | |
1196 | } | |
1197 | \f | |
1198 | /* Helper function for split_edge. Return true in case edge BB2 to BB1 | |
1199 | is back edge of syntactic loop. */ | |
1200 | ||
1201 | static bool | |
1202 | back_edge_of_syntactic_loop_p (bb1, bb2) | |
1203 | basic_block bb1, bb2; | |
1204 | { | |
1205 | rtx insn; | |
1206 | int count = 0; | |
1207 | ||
1208 | if (bb1->index > bb2->index) | |
1209 | return false; | |
5f0d2358 | 1210 | else if (bb1->index == bb2->index) |
ca6c03ca JH |
1211 | return true; |
1212 | ||
1213 | for (insn = bb1->end; insn != bb2->head && count >= 0; | |
1214 | insn = NEXT_INSN (insn)) | |
1215 | if (GET_CODE (insn) == NOTE) | |
1216 | { | |
1217 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) | |
1218 | count++; | |
5f0d2358 | 1219 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) |
ca6c03ca JH |
1220 | count--; |
1221 | } | |
1222 | ||
1223 | return count >= 0; | |
1224 | } | |
1225 | ||
1226 | /* Split a (typically critical) edge. Return the new block. | |
1227 | Abort on abnormal edges. | |
1228 | ||
1229 | ??? The code generally expects to be called on critical edges. | |
1230 | The case of a block ending in an unconditional jump to a | |
1231 | block with multiple predecessors is not handled optimally. */ | |
1232 | ||
1233 | basic_block | |
1234 | split_edge (edge_in) | |
1235 | edge edge_in; | |
1236 | { | |
1237 | basic_block bb; | |
1238 | edge edge_out; | |
1239 | rtx before; | |
1240 | ||
1241 | /* Abnormal edges cannot be split. */ | |
1242 | if ((edge_in->flags & EDGE_ABNORMAL) != 0) | |
1243 | abort (); | |
1244 | ||
1245 | /* We are going to place the new block in front of edge destination. | |
eaec9b3d | 1246 | Avoid existence of fallthru predecessors. */ |
ca6c03ca JH |
1247 | if ((edge_in->flags & EDGE_FALLTHRU) == 0) |
1248 | { | |
1249 | edge e; | |
5f0d2358 | 1250 | |
ca6c03ca JH |
1251 | for (e = edge_in->dest->pred; e; e = e->pred_next) |
1252 | if (e->flags & EDGE_FALLTHRU) | |
1253 | break; | |
1254 | ||
1255 | if (e) | |
1256 | force_nonfallthru (e); | |
1257 | } | |
1258 | ||
1259 | /* Create the basic block note. | |
1260 | ||
f63d1bf7 | 1261 | Where we place the note can have a noticeable impact on the generated |
ca6c03ca JH |
1262 | code. Consider this cfg: |
1263 | ||
1264 | E | |
1265 | | | |
1266 | 0 | |
1267 | / \ | |
1268 | +->1-->2--->E | |
1269 | | | | |
1270 | +--+ | |
1271 | ||
1272 | If we need to insert an insn on the edge from block 0 to block 1, | |
1273 | we want to ensure the instructions we insert are outside of any | |
1274 | loop notes that physically sit between block 0 and block 1. Otherwise | |
1275 | we confuse the loop optimizer into thinking the loop is a phony. */ | |
1276 | ||
1277 | if (edge_in->dest != EXIT_BLOCK_PTR | |
1278 | && PREV_INSN (edge_in->dest->head) | |
1279 | && GET_CODE (PREV_INSN (edge_in->dest->head)) == NOTE | |
5f0d2358 RK |
1280 | && (NOTE_LINE_NUMBER (PREV_INSN (edge_in->dest->head)) |
1281 | == NOTE_INSN_LOOP_BEG) | |
ca6c03ca JH |
1282 | && !back_edge_of_syntactic_loop_p (edge_in->dest, edge_in->src)) |
1283 | before = PREV_INSN (edge_in->dest->head); | |
1284 | else if (edge_in->dest != EXIT_BLOCK_PTR) | |
1285 | before = edge_in->dest->head; | |
1286 | else | |
1287 | before = NULL_RTX; | |
1288 | ||
1289 | bb = create_basic_block (edge_in->dest == EXIT_BLOCK_PTR ? n_basic_blocks | |
1290 | : edge_in->dest->index, before, NULL); | |
1291 | bb->count = edge_in->count; | |
1292 | bb->frequency = EDGE_FREQUENCY (edge_in); | |
1293 | ||
1294 | /* ??? This info is likely going to be out of date very soon. */ | |
1295 | if (edge_in->dest->global_live_at_start) | |
1296 | { | |
1297 | bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack); | |
1298 | bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack); | |
5f0d2358 RK |
1299 | COPY_REG_SET (bb->global_live_at_start, |
1300 | edge_in->dest->global_live_at_start); | |
1301 | COPY_REG_SET (bb->global_live_at_end, | |
1302 | edge_in->dest->global_live_at_start); | |
ca6c03ca JH |
1303 | } |
1304 | ||
1305 | edge_out = make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU); | |
1306 | ||
1307 | /* For non-fallthry edges, we must adjust the predecessor's | |
1308 | jump instruction to target our new block. */ | |
1309 | if ((edge_in->flags & EDGE_FALLTHRU) == 0) | |
1310 | { | |
1311 | if (!redirect_edge_and_branch (edge_in, bb)) | |
1312 | abort (); | |
1313 | } | |
1314 | else | |
1315 | redirect_edge_succ (edge_in, bb); | |
1316 | ||
1317 | return bb; | |
1318 | } | |
1319 | ||
1320 | /* Queue instructions for insertion on an edge between two basic blocks. | |
1321 | The new instructions and basic blocks (if any) will not appear in the | |
1322 | CFG until commit_edge_insertions is called. */ | |
1323 | ||
1324 | void | |
1325 | insert_insn_on_edge (pattern, e) | |
1326 | rtx pattern; | |
1327 | edge e; | |
1328 | { | |
1329 | /* We cannot insert instructions on an abnormal critical edge. | |
1330 | It will be easier to find the culprit if we die now. */ | |
1331 | if ((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)) | |
1332 | abort (); | |
1333 | ||
1334 | if (e->insns == NULL_RTX) | |
1335 | start_sequence (); | |
1336 | else | |
1337 | push_to_sequence (e->insns); | |
1338 | ||
1339 | emit_insn (pattern); | |
1340 | ||
1341 | e->insns = get_insns (); | |
1342 | end_sequence (); | |
1343 | } | |
1344 | ||
1345 | /* Update the CFG for the instructions queued on edge E. */ | |
1346 | ||
1347 | static void | |
3dec4024 | 1348 | commit_one_edge_insertion (e, watch_calls) |
ca6c03ca | 1349 | edge e; |
3dec4024 | 1350 | int watch_calls; |
ca6c03ca JH |
1351 | { |
1352 | rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last; | |
1353 | basic_block bb; | |
1354 | ||
1355 | /* Pull the insns off the edge now since the edge might go away. */ | |
1356 | insns = e->insns; | |
1357 | e->insns = NULL_RTX; | |
1358 | ||
3dec4024 JH |
1359 | /* Special case -- avoid inserting code between call and storing |
1360 | its return value. */ | |
1361 | if (watch_calls && (e->flags & EDGE_FALLTHRU) && !e->dest->pred->pred_next | |
1362 | && e->src != ENTRY_BLOCK_PTR | |
1363 | && GET_CODE (e->src->end) == CALL_INSN) | |
ca6c03ca | 1364 | { |
3dec4024 | 1365 | rtx next = next_nonnote_insn (e->src->end); |
ca6c03ca | 1366 | |
3dec4024 JH |
1367 | after = e->dest->head; |
1368 | /* The first insn after the call may be a stack pop, skip it. */ | |
1369 | while (next | |
1370 | && keep_with_call_p (next)) | |
1371 | { | |
1372 | after = next; | |
1373 | next = next_nonnote_insn (next); | |
1374 | } | |
1375 | bb = e->dest; | |
ca6c03ca | 1376 | } |
3dec4024 | 1377 | if (!before && !after) |
ca6c03ca | 1378 | { |
3dec4024 JH |
1379 | /* Figure out where to put these things. If the destination has |
1380 | one predecessor, insert there. Except for the exit block. */ | |
1381 | if (e->dest->pred->pred_next == NULL && e->dest != EXIT_BLOCK_PTR) | |
ca6c03ca | 1382 | { |
3dec4024 JH |
1383 | bb = e->dest; |
1384 | ||
1385 | /* Get the location correct wrt a code label, and "nice" wrt | |
1386 | a basic block note, and before everything else. */ | |
1387 | tmp = bb->head; | |
1388 | if (GET_CODE (tmp) == CODE_LABEL) | |
1389 | tmp = NEXT_INSN (tmp); | |
1390 | if (NOTE_INSN_BASIC_BLOCK_P (tmp)) | |
1391 | tmp = NEXT_INSN (tmp); | |
1392 | if (tmp == bb->head) | |
1393 | before = tmp; | |
1394 | else if (tmp) | |
1395 | after = PREV_INSN (tmp); | |
1396 | else | |
1397 | after = get_last_insn (); | |
1398 | } | |
1399 | ||
1400 | /* If the source has one successor and the edge is not abnormal, | |
1401 | insert there. Except for the entry block. */ | |
1402 | else if ((e->flags & EDGE_ABNORMAL) == 0 | |
1403 | && e->src->succ->succ_next == NULL | |
1404 | && e->src != ENTRY_BLOCK_PTR) | |
1405 | { | |
1406 | bb = e->src; | |
1407 | ||
1408 | /* It is possible to have a non-simple jump here. Consider a target | |
1409 | where some forms of unconditional jumps clobber a register. This | |
1410 | happens on the fr30 for example. | |
1411 | ||
1412 | We know this block has a single successor, so we can just emit | |
1413 | the queued insns before the jump. */ | |
1414 | if (GET_CODE (bb->end) == JUMP_INSN) | |
1415 | for (before = bb->end; | |
1416 | GET_CODE (PREV_INSN (before)) == NOTE | |
1417 | && NOTE_LINE_NUMBER (PREV_INSN (before)) == | |
1418 | NOTE_INSN_LOOP_BEG; before = PREV_INSN (before)) | |
1419 | ; | |
1420 | else | |
1421 | { | |
1422 | /* We'd better be fallthru, or we've lost track of what's what. */ | |
1423 | if ((e->flags & EDGE_FALLTHRU) == 0) | |
1424 | abort (); | |
ca6c03ca | 1425 | |
3dec4024 JH |
1426 | after = bb->end; |
1427 | } | |
1428 | } | |
1429 | /* Otherwise we must split the edge. */ | |
1430 | else | |
1431 | { | |
1432 | bb = split_edge (e); | |
ca6c03ca JH |
1433 | after = bb->end; |
1434 | } | |
1435 | } | |
1436 | ||
ca6c03ca JH |
1437 | /* Now that we've found the spot, do the insertion. */ |
1438 | ||
1439 | if (before) | |
1440 | { | |
1441 | emit_insns_before (insns, before); | |
1442 | last = prev_nonnote_insn (before); | |
1443 | } | |
1444 | else | |
1445 | last = emit_insns_after (insns, after); | |
1446 | ||
1447 | if (returnjump_p (last)) | |
1448 | { | |
1449 | /* ??? Remove all outgoing edges from BB and add one for EXIT. | |
1450 | This is not currently a problem because this only happens | |
3dec4024 JH |
1451 | for the (single) epilogue, which already has a fallthru edge |
1452 | to EXIT. */ | |
ca6c03ca JH |
1453 | |
1454 | e = bb->succ; | |
1455 | if (e->dest != EXIT_BLOCK_PTR | |
3dec4024 | 1456 | || e->succ_next != NULL || (e->flags & EDGE_FALLTHRU) == 0) |
ca6c03ca | 1457 | abort (); |
ca6c03ca | 1458 | |
5f0d2358 | 1459 | e->flags &= ~EDGE_FALLTHRU; |
ca6c03ca JH |
1460 | emit_barrier_after (last); |
1461 | ||
1462 | if (before) | |
1463 | delete_insn (before); | |
1464 | } | |
1465 | else if (GET_CODE (last) == JUMP_INSN) | |
1466 | abort (); | |
5f0d2358 | 1467 | |
ca6c03ca JH |
1468 | find_sub_basic_blocks (bb); |
1469 | } | |
1470 | ||
1471 | /* Update the CFG for all queued instructions. */ | |
1472 | ||
1473 | void | |
1474 | commit_edge_insertions () | |
1475 | { | |
1476 | int i; | |
1477 | basic_block bb; | |
1478 | ||
1479 | #ifdef ENABLE_CHECKING | |
1480 | verify_flow_info (); | |
1481 | #endif | |
1482 | ||
1483 | i = -1; | |
1484 | bb = ENTRY_BLOCK_PTR; | |
1485 | while (1) | |
1486 | { | |
1487 | edge e, next; | |
1488 | ||
1489 | for (e = bb->succ; e; e = next) | |
1490 | { | |
1491 | next = e->succ_next; | |
1492 | if (e->insns) | |
3dec4024 JH |
1493 | commit_one_edge_insertion (e, false); |
1494 | } | |
1495 | ||
1496 | if (++i >= n_basic_blocks) | |
1497 | break; | |
1498 | bb = BASIC_BLOCK (i); | |
1499 | } | |
1500 | } | |
1501 | \f | |
1502 | /* Update the CFG for all queued instructions, taking special care of inserting | |
1503 | code on edges between call and storing its return value. */ | |
1504 | ||
1505 | void | |
1506 | commit_edge_insertions_watch_calls () | |
1507 | { | |
1508 | int i; | |
1509 | basic_block bb; | |
1510 | ||
1511 | #ifdef ENABLE_CHECKING | |
1512 | verify_flow_info (); | |
1513 | #endif | |
1514 | ||
1515 | i = -1; | |
1516 | bb = ENTRY_BLOCK_PTR; | |
1517 | while (1) | |
1518 | { | |
1519 | edge e, next; | |
1520 | ||
1521 | for (e = bb->succ; e; e = next) | |
1522 | { | |
1523 | next = e->succ_next; | |
1524 | if (e->insns) | |
1525 | commit_one_edge_insertion (e, true); | |
ca6c03ca JH |
1526 | } |
1527 | ||
1528 | if (++i >= n_basic_blocks) | |
1529 | break; | |
1530 | bb = BASIC_BLOCK (i); | |
1531 | } | |
1532 | } | |
1533 | \f | |
1534 | /* Print out one basic block with live information at start and end. */ | |
1535 | ||
1536 | void | |
1537 | dump_bb (bb, outf) | |
1538 | basic_block bb; | |
1539 | FILE *outf; | |
1540 | { | |
1541 | rtx insn; | |
1542 | rtx last; | |
1543 | edge e; | |
1544 | ||
1545 | fprintf (outf, ";; Basic block %d, loop depth %d, count ", | |
1546 | bb->index, bb->loop_depth); | |
1547 | fprintf (outf, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count); | |
1548 | putc ('\n', outf); | |
1549 | ||
1550 | fputs (";; Predecessors: ", outf); | |
1551 | for (e = bb->pred; e; e = e->pred_next) | |
1552 | dump_edge_info (outf, e, 0); | |
1553 | putc ('\n', outf); | |
1554 | ||
1555 | fputs (";; Registers live at start:", outf); | |
1556 | dump_regset (bb->global_live_at_start, outf); | |
1557 | putc ('\n', outf); | |
1558 | ||
5f0d2358 | 1559 | for (insn = bb->head, last = NEXT_INSN (bb->end); insn != last; |
ca6c03ca JH |
1560 | insn = NEXT_INSN (insn)) |
1561 | print_rtl_single (outf, insn); | |
1562 | ||
1563 | fputs (";; Registers live at end:", outf); | |
1564 | dump_regset (bb->global_live_at_end, outf); | |
1565 | putc ('\n', outf); | |
1566 | ||
1567 | fputs (";; Successors: ", outf); | |
1568 | for (e = bb->succ; e; e = e->succ_next) | |
1569 | dump_edge_info (outf, e, 1); | |
1570 | putc ('\n', outf); | |
1571 | } | |
1572 | ||
1573 | void | |
1574 | debug_bb (bb) | |
1575 | basic_block bb; | |
1576 | { | |
1577 | dump_bb (bb, stderr); | |
1578 | } | |
1579 | ||
1580 | void | |
1581 | debug_bb_n (n) | |
1582 | int n; | |
1583 | { | |
1584 | dump_bb (BASIC_BLOCK (n), stderr); | |
1585 | } | |
1586 | \f | |
1587 | /* Like print_rtl, but also print out live information for the start of each | |
1588 | basic block. */ | |
1589 | ||
1590 | void | |
1591 | print_rtl_with_bb (outf, rtx_first) | |
1592 | FILE *outf; | |
1593 | rtx rtx_first; | |
1594 | { | |
b3694847 | 1595 | rtx tmp_rtx; |
ca6c03ca JH |
1596 | |
1597 | if (rtx_first == 0) | |
1598 | fprintf (outf, "(nil)\n"); | |
1599 | else | |
1600 | { | |
1601 | int i; | |
1602 | enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB }; | |
1603 | int max_uid = get_max_uid (); | |
5f0d2358 RK |
1604 | basic_block *start |
1605 | = (basic_block *) xcalloc (max_uid, sizeof (basic_block)); | |
1606 | basic_block *end | |
1607 | = (basic_block *) xcalloc (max_uid, sizeof (basic_block)); | |
1608 | enum bb_state *in_bb_p | |
1609 | = (enum bb_state *) xcalloc (max_uid, sizeof (enum bb_state)); | |
ca6c03ca JH |
1610 | |
1611 | for (i = n_basic_blocks - 1; i >= 0; i--) | |
1612 | { | |
1613 | basic_block bb = BASIC_BLOCK (i); | |
1614 | rtx x; | |
1615 | ||
1616 | start[INSN_UID (bb->head)] = bb; | |
1617 | end[INSN_UID (bb->end)] = bb; | |
1618 | for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x)) | |
1619 | { | |
1620 | enum bb_state state = IN_MULTIPLE_BB; | |
5f0d2358 | 1621 | |
ca6c03ca JH |
1622 | if (in_bb_p[INSN_UID (x)] == NOT_IN_BB) |
1623 | state = IN_ONE_BB; | |
1624 | in_bb_p[INSN_UID (x)] = state; | |
1625 | ||
1626 | if (x == bb->end) | |
1627 | break; | |
1628 | } | |
1629 | } | |
1630 | ||
1631 | for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx)) | |
1632 | { | |
1633 | int did_output; | |
1634 | basic_block bb; | |
1635 | ||
1636 | if ((bb = start[INSN_UID (tmp_rtx)]) != NULL) | |
1637 | { | |
1638 | fprintf (outf, ";; Start of basic block %d, registers live:", | |
1639 | bb->index); | |
1640 | dump_regset (bb->global_live_at_start, outf); | |
1641 | putc ('\n', outf); | |
1642 | } | |
1643 | ||
1644 | if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB | |
1645 | && GET_CODE (tmp_rtx) != NOTE | |
1646 | && GET_CODE (tmp_rtx) != BARRIER) | |
1647 | fprintf (outf, ";; Insn is not within a basic block\n"); | |
1648 | else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB) | |
1649 | fprintf (outf, ";; Insn is in multiple basic blocks\n"); | |
1650 | ||
1651 | did_output = print_rtl_single (outf, tmp_rtx); | |
1652 | ||
1653 | if ((bb = end[INSN_UID (tmp_rtx)]) != NULL) | |
1654 | { | |
1655 | fprintf (outf, ";; End of basic block %d, registers live:\n", | |
1656 | bb->index); | |
1657 | dump_regset (bb->global_live_at_end, outf); | |
1658 | putc ('\n', outf); | |
1659 | } | |
1660 | ||
1661 | if (did_output) | |
1662 | putc ('\n', outf); | |
1663 | } | |
1664 | ||
1665 | free (start); | |
1666 | free (end); | |
1667 | free (in_bb_p); | |
1668 | } | |
1669 | ||
1670 | if (current_function_epilogue_delay_list != 0) | |
1671 | { | |
1672 | fprintf (outf, "\n;; Insns in epilogue delay list:\n\n"); | |
1673 | for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0; | |
1674 | tmp_rtx = XEXP (tmp_rtx, 1)) | |
1675 | print_rtl_single (outf, XEXP (tmp_rtx, 0)); | |
1676 | } | |
1677 | } | |
1678 | \f | |
b446e5a2 JH |
1679 | void |
1680 | update_br_prob_note (bb) | |
1681 | basic_block bb; | |
1682 | { | |
1683 | rtx note; | |
1684 | if (GET_CODE (bb->end) != JUMP_INSN) | |
1685 | return; | |
1686 | note = find_reg_note (bb->end, REG_BR_PROB, NULL_RTX); | |
1687 | if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability) | |
1688 | return; | |
1689 | XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability); | |
1690 | } | |
1691 | \f | |
ca6c03ca JH |
1692 | /* Verify the CFG consistency. This function check some CFG invariants and |
1693 | aborts when something is wrong. Hope that this function will help to | |
1694 | convert many optimization passes to preserve CFG consistent. | |
1695 | ||
1696 | Currently it does following checks: | |
1697 | ||
1698 | - test head/end pointers | |
1699 | - overlapping of basic blocks | |
1700 | - edge list correctness | |
1701 | - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note) | |
f63d1bf7 | 1702 | - tails of basic blocks (ensure that boundary is necessary) |
ca6c03ca JH |
1703 | - scans body of the basic block for JUMP_INSN, CODE_LABEL |
1704 | and NOTE_INSN_BASIC_BLOCK | |
1705 | - check that all insns are in the basic blocks | |
5f0d2358 | 1706 | (except the switch handling code, barriers and notes) |
ca6c03ca JH |
1707 | - check that all returns are followed by barriers |
1708 | ||
1709 | In future it can be extended check a lot of other stuff as well | |
1710 | (reachability of basic blocks, life information, etc. etc.). */ | |
1711 | ||
1712 | void | |
1713 | verify_flow_info () | |
1714 | { | |
1715 | const int max_uid = get_max_uid (); | |
1716 | const rtx rtx_first = get_insns (); | |
1717 | rtx last_head = get_last_insn (); | |
1718 | basic_block *bb_info, *last_visited; | |
1719 | size_t *edge_checksum; | |
1720 | rtx x; | |
1721 | int i, last_bb_num_seen, num_bb_notes, err = 0; | |
1722 | ||
1723 | bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block)); | |
1724 | last_visited = (basic_block *) xcalloc (n_basic_blocks + 2, | |
1725 | sizeof (basic_block)); | |
1726 | edge_checksum = (size_t *) xcalloc (n_basic_blocks + 2, sizeof (size_t)); | |
1727 | ||
1728 | for (i = n_basic_blocks - 1; i >= 0; i--) | |
1729 | { | |
1730 | basic_block bb = BASIC_BLOCK (i); | |
1731 | rtx head = bb->head; | |
1732 | rtx end = bb->end; | |
1733 | ||
1734 | /* Verify the end of the basic block is in the INSN chain. */ | |
1735 | for (x = last_head; x != NULL_RTX; x = PREV_INSN (x)) | |
1736 | if (x == end) | |
1737 | break; | |
5f0d2358 | 1738 | |
ca6c03ca JH |
1739 | if (!x) |
1740 | { | |
1f978f5f | 1741 | error ("end insn %d for block %d not found in the insn stream", |
ca6c03ca JH |
1742 | INSN_UID (end), bb->index); |
1743 | err = 1; | |
1744 | } | |
1745 | ||
1746 | /* Work backwards from the end to the head of the basic block | |
1747 | to verify the head is in the RTL chain. */ | |
1748 | for (; x != NULL_RTX; x = PREV_INSN (x)) | |
1749 | { | |
1750 | /* While walking over the insn chain, verify insns appear | |
1751 | in only one basic block and initialize the BB_INFO array | |
1752 | used by other passes. */ | |
1753 | if (bb_info[INSN_UID (x)] != NULL) | |
1754 | { | |
1f978f5f | 1755 | error ("insn %d is in multiple basic blocks (%d and %d)", |
ca6c03ca JH |
1756 | INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index); |
1757 | err = 1; | |
1758 | } | |
5f0d2358 | 1759 | |
ca6c03ca JH |
1760 | bb_info[INSN_UID (x)] = bb; |
1761 | ||
1762 | if (x == head) | |
1763 | break; | |
1764 | } | |
1765 | if (!x) | |
1766 | { | |
1f978f5f | 1767 | error ("head insn %d for block %d not found in the insn stream", |
ca6c03ca JH |
1768 | INSN_UID (head), bb->index); |
1769 | err = 1; | |
1770 | } | |
1771 | ||
1772 | last_head = x; | |
1773 | } | |
1774 | ||
1775 | /* Now check the basic blocks (boundaries etc.) */ | |
1776 | for (i = n_basic_blocks - 1; i >= 0; i--) | |
1777 | { | |
1778 | basic_block bb = BASIC_BLOCK (i); | |
3dec4024 | 1779 | int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0; |
ca6c03ca | 1780 | edge e; |
5a1a3e5e | 1781 | rtx note; |
ca6c03ca | 1782 | |
5a1a3e5e | 1783 | if (INSN_P (bb->end) |
1e3881c2 | 1784 | && (note = find_reg_note (bb->end, REG_BR_PROB, NULL_RTX)) |
3e638a90 | 1785 | && bb->succ && bb->succ->succ_next |
1e3881c2 | 1786 | && any_condjump_p (bb->end)) |
5a1a3e5e | 1787 | { |
5a1a3e5e JH |
1788 | if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability) |
1789 | { | |
1790 | error ("verify_flow_info: REG_BR_PROB does not match cfg %i %i", | |
1791 | INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability); | |
1792 | err = 1; | |
1793 | } | |
1794 | } | |
1795 | if (bb->count < 0) | |
1796 | { | |
1797 | error ("verify_flow_info: Wrong count of block %i %i", | |
1798 | bb->index, (int)bb->count); | |
1799 | err = 1; | |
1800 | } | |
1801 | if (bb->frequency < 0) | |
1802 | { | |
1803 | error ("verify_flow_info: Wrong frequency of block %i %i", | |
1804 | bb->index, bb->frequency); | |
1805 | err = 1; | |
1806 | } | |
5f0d2358 | 1807 | for (e = bb->succ; e; e = e->succ_next) |
ca6c03ca JH |
1808 | { |
1809 | if (last_visited [e->dest->index + 2] == bb) | |
1810 | { | |
1811 | error ("verify_flow_info: Duplicate edge %i->%i", | |
1812 | e->src->index, e->dest->index); | |
1813 | err = 1; | |
1814 | } | |
5a1a3e5e JH |
1815 | if (e->probability < 0 || e->probability > REG_BR_PROB_BASE) |
1816 | { | |
1817 | error ("verify_flow_info: Wrong probability of edge %i->%i %i", | |
1818 | e->src->index, e->dest->index, e->probability); | |
1819 | err = 1; | |
1820 | } | |
1821 | if (e->count < 0) | |
1822 | { | |
1823 | error ("verify_flow_info: Wrong count of edge %i->%i %i", | |
1824 | e->src->index, e->dest->index, (int)e->count); | |
1825 | err = 1; | |
1826 | } | |
5f0d2358 | 1827 | |
ca6c03ca JH |
1828 | last_visited [e->dest->index + 2] = bb; |
1829 | ||
1830 | if (e->flags & EDGE_FALLTHRU) | |
3dec4024 JH |
1831 | n_fallthru++; |
1832 | ||
1833 | if ((e->flags & ~EDGE_DFS_BACK) == 0) | |
1834 | n_branch++; | |
1835 | ||
1836 | if (e->flags & EDGE_ABNORMAL_CALL) | |
1837 | n_call++; | |
1838 | ||
1839 | if (e->flags & EDGE_EH) | |
1840 | n_eh++; | |
1841 | else if (e->flags & EDGE_ABNORMAL) | |
1842 | n_abnormal++; | |
ca6c03ca JH |
1843 | |
1844 | if ((e->flags & EDGE_FALLTHRU) | |
1845 | && e->src != ENTRY_BLOCK_PTR | |
1846 | && e->dest != EXIT_BLOCK_PTR) | |
1847 | { | |
1848 | rtx insn; | |
5f0d2358 | 1849 | |
ca6c03ca JH |
1850 | if (e->src->index + 1 != e->dest->index) |
1851 | { | |
5f0d2358 RK |
1852 | error |
1853 | ("verify_flow_info: Incorrect blocks for fallthru %i->%i", | |
1854 | e->src->index, e->dest->index); | |
1855 | err = 1; | |
ca6c03ca JH |
1856 | } |
1857 | else | |
1858 | for (insn = NEXT_INSN (e->src->end); insn != e->dest->head; | |
1859 | insn = NEXT_INSN (insn)) | |
32a6f30e JDA |
1860 | if (GET_CODE (insn) == BARRIER |
1861 | #ifndef CASE_DROPS_THROUGH | |
5f0d2358 | 1862 | || INSN_P (insn) |
32a6f30e | 1863 | #else |
5f0d2358 | 1864 | || (INSN_P (insn) && ! JUMP_TABLE_DATA_P (insn)) |
32a6f30e | 1865 | #endif |
5f0d2358 | 1866 | ) |
ca6c03ca JH |
1867 | { |
1868 | error ("verify_flow_info: Incorrect fallthru %i->%i", | |
1869 | e->src->index, e->dest->index); | |
1f978f5f | 1870 | fatal_insn ("wrong insn in the fallthru edge", insn); |
ca6c03ca JH |
1871 | err = 1; |
1872 | } | |
1873 | } | |
5f0d2358 | 1874 | |
ca6c03ca JH |
1875 | if (e->src != bb) |
1876 | { | |
1877 | error ("verify_flow_info: Basic block %d succ edge is corrupted", | |
1878 | bb->index); | |
1879 | fprintf (stderr, "Predecessor: "); | |
1880 | dump_edge_info (stderr, e, 0); | |
1881 | fprintf (stderr, "\nSuccessor: "); | |
1882 | dump_edge_info (stderr, e, 1); | |
1883 | fprintf (stderr, "\n"); | |
1884 | err = 1; | |
1885 | } | |
5f0d2358 | 1886 | |
ca6c03ca | 1887 | edge_checksum[e->dest->index + 2] += (size_t) e; |
ca6c03ca | 1888 | } |
5f0d2358 | 1889 | |
a2877a09 JH |
1890 | if (n_eh && GET_CODE (PATTERN (bb->end)) != RESX |
1891 | && !find_reg_note (bb->end, REG_EH_REGION, NULL_RTX)) | |
3dec4024 JH |
1892 | { |
1893 | error ("Missing REG_EH_REGION note in the end of bb %i", bb->index); | |
1894 | err = 1; | |
1895 | } | |
1896 | if (n_branch | |
1897 | && (GET_CODE (bb->end) != JUMP_INSN | |
1898 | || (n_branch > 1 && (any_uncondjump_p (bb->end) | |
1899 | || any_condjump_p (bb->end))))) | |
1900 | { | |
1901 | error ("Too many outgoing branch edges from bb %i", bb->index); | |
1902 | err = 1; | |
1903 | } | |
1904 | if (n_fallthru && any_uncondjump_p (bb->end)) | |
1905 | { | |
1906 | error ("Fallthru edge after unconditional jump %i", bb->index); | |
1907 | err = 1; | |
1908 | } | |
1909 | if (n_branch != 1 && any_uncondjump_p (bb->end)) | |
1910 | { | |
1911 | error ("Wrong amount of branch edges after unconditional jump %i", bb->index); | |
1912 | err = 1; | |
1913 | } | |
1914 | if (n_branch != 1 && any_condjump_p (bb->end) | |
1915 | && JUMP_LABEL (bb->end) != BASIC_BLOCK (bb->index + 1)->head) | |
1916 | { | |
1917 | error ("Wrong amount of branch edges after conditional jump %i", bb->index); | |
1918 | err = 1; | |
1919 | } | |
1920 | if (n_call && GET_CODE (bb->end) != CALL_INSN) | |
1921 | { | |
1922 | error ("Call edges for non-call insn in bb %i", bb->index); | |
1923 | err = 1; | |
1924 | } | |
1925 | if (n_abnormal | |
1926 | && (GET_CODE (bb->end) != CALL_INSN && n_call != n_abnormal) | |
1927 | && (GET_CODE (bb->end) != JUMP_INSN | |
1928 | || any_condjump_p (bb->end) | |
1929 | || any_uncondjump_p (bb->end))) | |
1930 | { | |
1931 | error ("Abnormal edges for no purpose in bb %i", bb->index); | |
1932 | err = 1; | |
1933 | } | |
1934 | ||
1935 | if (!n_fallthru) | |
ca6c03ca | 1936 | { |
09eb1aab | 1937 | rtx insn; |
ca6c03ca JH |
1938 | |
1939 | /* Ensure existence of barrier in BB with no fallthru edges. */ | |
09eb1aab | 1940 | for (insn = bb->end; !insn || GET_CODE (insn) != BARRIER; |
ca6c03ca JH |
1941 | insn = NEXT_INSN (insn)) |
1942 | if (!insn | |
1943 | || (GET_CODE (insn) == NOTE | |
1944 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_BASIC_BLOCK)) | |
1945 | { | |
1f978f5f | 1946 | error ("missing barrier after block %i", bb->index); |
ca6c03ca | 1947 | err = 1; |
09eb1aab | 1948 | break; |
ca6c03ca JH |
1949 | } |
1950 | } | |
1951 | ||
5f0d2358 | 1952 | for (e = bb->pred; e; e = e->pred_next) |
ca6c03ca JH |
1953 | { |
1954 | if (e->dest != bb) | |
1955 | { | |
1f978f5f | 1956 | error ("basic block %d pred edge is corrupted", bb->index); |
ca6c03ca JH |
1957 | fputs ("Predecessor: ", stderr); |
1958 | dump_edge_info (stderr, e, 0); | |
1959 | fputs ("\nSuccessor: ", stderr); | |
1960 | dump_edge_info (stderr, e, 1); | |
1961 | fputc ('\n', stderr); | |
1962 | err = 1; | |
1963 | } | |
1964 | edge_checksum[e->dest->index + 2] -= (size_t) e; | |
ca6c03ca | 1965 | } |
5f0d2358 RK |
1966 | |
1967 | for (x = bb->head; x != NEXT_INSN (bb->end); x = NEXT_INSN (x)) | |
1968 | if (basic_block_for_insn && BLOCK_FOR_INSN (x) != bb) | |
1969 | { | |
1970 | debug_rtx (x); | |
1971 | if (! BLOCK_FOR_INSN (x)) | |
1972 | error | |
1973 | ("insn %d inside basic block %d but block_for_insn is NULL", | |
1974 | INSN_UID (x), bb->index); | |
1975 | else | |
1976 | error | |
1977 | ("insn %d inside basic block %d but block_for_insn is %i", | |
1978 | INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index); | |
1979 | ||
1980 | err = 1; | |
1981 | } | |
ca6c03ca JH |
1982 | |
1983 | /* OK pointers are correct. Now check the header of basic | |
1984 | block. It ought to contain optional CODE_LABEL followed | |
1985 | by NOTE_BASIC_BLOCK. */ | |
1986 | x = bb->head; | |
1987 | if (GET_CODE (x) == CODE_LABEL) | |
1988 | { | |
1989 | if (bb->end == x) | |
1990 | { | |
1991 | error ("NOTE_INSN_BASIC_BLOCK is missing for block %d", | |
1992 | bb->index); | |
1993 | err = 1; | |
1994 | } | |
5f0d2358 | 1995 | |
ca6c03ca JH |
1996 | x = NEXT_INSN (x); |
1997 | } | |
5f0d2358 | 1998 | |
ca6c03ca JH |
1999 | if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb) |
2000 | { | |
2001 | error ("NOTE_INSN_BASIC_BLOCK is missing for block %d", | |
2002 | bb->index); | |
2003 | err = 1; | |
2004 | } | |
2005 | ||
2006 | if (bb->end == x) | |
5f0d2358 RK |
2007 | /* Do checks for empty blocks her. e */ |
2008 | ; | |
ca6c03ca | 2009 | else |
5f0d2358 RK |
2010 | for (x = NEXT_INSN (x); x; x = NEXT_INSN (x)) |
2011 | { | |
2012 | if (NOTE_INSN_BASIC_BLOCK_P (x)) | |
2013 | { | |
2014 | error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d", | |
2015 | INSN_UID (x), bb->index); | |
2016 | err = 1; | |
2017 | } | |
2018 | ||
2019 | if (x == bb->end) | |
2020 | break; | |
ca6c03ca | 2021 | |
5f0d2358 RK |
2022 | if (GET_CODE (x) == JUMP_INSN |
2023 | || GET_CODE (x) == CODE_LABEL | |
2024 | || GET_CODE (x) == BARRIER) | |
2025 | { | |
2026 | error ("in basic block %d:", bb->index); | |
2027 | fatal_insn ("flow control insn inside a basic block", x); | |
2028 | } | |
2029 | } | |
ca6c03ca JH |
2030 | } |
2031 | ||
2032 | /* Complete edge checksumming for ENTRY and EXIT. */ | |
2033 | { | |
2034 | edge e; | |
5f0d2358 | 2035 | |
ca6c03ca JH |
2036 | for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next) |
2037 | edge_checksum[e->dest->index + 2] += (size_t) e; | |
5f0d2358 | 2038 | |
ca6c03ca JH |
2039 | for (e = EXIT_BLOCK_PTR->pred; e ; e = e->pred_next) |
2040 | edge_checksum[e->dest->index + 2] -= (size_t) e; | |
2041 | } | |
2042 | ||
2043 | for (i = -2; i < n_basic_blocks; ++i) | |
2044 | if (edge_checksum[i + 2]) | |
2045 | { | |
1f978f5f | 2046 | error ("basic block %i edge lists are corrupted", i); |
ca6c03ca JH |
2047 | err = 1; |
2048 | } | |
2049 | ||
2050 | last_bb_num_seen = -1; | |
2051 | num_bb_notes = 0; | |
5f0d2358 | 2052 | for (x = rtx_first; x; x = NEXT_INSN (x)) |
ca6c03ca JH |
2053 | { |
2054 | if (NOTE_INSN_BASIC_BLOCK_P (x)) | |
2055 | { | |
2056 | basic_block bb = NOTE_BASIC_BLOCK (x); | |
5f0d2358 | 2057 | |
ca6c03ca JH |
2058 | num_bb_notes++; |
2059 | if (bb->index != last_bb_num_seen + 1) | |
c725bd79 | 2060 | internal_error ("basic blocks not numbered consecutively"); |
ca6c03ca JH |
2061 | |
2062 | last_bb_num_seen = bb->index; | |
2063 | } | |
2064 | ||
2065 | if (!bb_info[INSN_UID (x)]) | |
2066 | { | |
2067 | switch (GET_CODE (x)) | |
2068 | { | |
2069 | case BARRIER: | |
2070 | case NOTE: | |
2071 | break; | |
2072 | ||
2073 | case CODE_LABEL: | |
2074 | /* An addr_vec is placed outside any block block. */ | |
2075 | if (NEXT_INSN (x) | |
2076 | && GET_CODE (NEXT_INSN (x)) == JUMP_INSN | |
2077 | && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC | |
2078 | || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC)) | |
5f0d2358 | 2079 | x = NEXT_INSN (x); |
ca6c03ca JH |
2080 | |
2081 | /* But in any case, non-deletable labels can appear anywhere. */ | |
2082 | break; | |
2083 | ||
2084 | default: | |
1f978f5f | 2085 | fatal_insn ("insn outside basic block", x); |
ca6c03ca JH |
2086 | } |
2087 | } | |
2088 | ||
2089 | if (INSN_P (x) | |
2090 | && GET_CODE (x) == JUMP_INSN | |
2091 | && returnjump_p (x) && ! condjump_p (x) | |
2092 | && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER)) | |
1f978f5f | 2093 | fatal_insn ("return not followed by barrier", x); |
ca6c03ca JH |
2094 | } |
2095 | ||
2096 | if (num_bb_notes != n_basic_blocks) | |
2097 | internal_error | |
2098 | ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)", | |
2099 | num_bb_notes, n_basic_blocks); | |
2100 | ||
2101 | if (err) | |
c725bd79 | 2102 | internal_error ("verify_flow_info failed"); |
ca6c03ca JH |
2103 | |
2104 | /* Clean up. */ | |
2105 | free (bb_info); | |
2106 | free (last_visited); | |
2107 | free (edge_checksum); | |
2108 | } | |
2109 | \f | |
eaec9b3d | 2110 | /* Assume that the preceding pass has possibly eliminated jump instructions |
ca6c03ca JH |
2111 | or converted the unconditional jumps. Eliminate the edges from CFG. |
2112 | Return true if any edges are eliminated. */ | |
2113 | ||
2114 | bool | |
2115 | purge_dead_edges (bb) | |
2116 | basic_block bb; | |
2117 | { | |
2118 | edge e, next; | |
89753b3a | 2119 | rtx insn = bb->end, note; |
ca6c03ca JH |
2120 | bool purged = false; |
2121 | ||
70da1d03 JH |
2122 | /* If this instruction cannot trap, remove REG_EH_REGION notes. */ |
2123 | if (GET_CODE (insn) == INSN | |
2124 | && (note = find_reg_note (insn, REG_EH_REGION, NULL))) | |
2125 | { | |
2126 | rtx eqnote; | |
2127 | ||
2128 | if (! may_trap_p (PATTERN (insn)) | |
2129 | || ((eqnote = find_reg_equal_equiv_note (insn)) | |
2130 | && ! may_trap_p (XEXP (eqnote, 0)))) | |
2131 | remove_note (insn, note); | |
2132 | } | |
2133 | ||
2134 | /* Cleanup abnormal edges caused by throwing insns that have been | |
2135 | eliminated. */ | |
2136 | if (! can_throw_internal (bb->end)) | |
2137 | for (e = bb->succ; e; e = next) | |
2138 | { | |
2139 | next = e->succ_next; | |
2140 | if (e->flags & EDGE_EH) | |
2141 | { | |
2142 | remove_edge (e); | |
c51d95ec | 2143 | bb->flags |= BB_DIRTY; |
70da1d03 JH |
2144 | purged = true; |
2145 | } | |
2146 | } | |
5f0d2358 | 2147 | |
ca6c03ca JH |
2148 | if (GET_CODE (insn) == JUMP_INSN) |
2149 | { | |
2150 | rtx note; | |
2151 | edge b,f; | |
5f0d2358 | 2152 | |
ca6c03ca JH |
2153 | /* We do care only about conditional jumps and simplejumps. */ |
2154 | if (!any_condjump_p (insn) | |
2155 | && !returnjump_p (insn) | |
2156 | && !simplejump_p (insn)) | |
c51d95ec | 2157 | return purged; |
5f0d2358 | 2158 | |
5a1a3e5e JH |
2159 | /* Branch probability/prediction notes are defined only for |
2160 | condjumps. We've possibly turned condjump into simplejump. */ | |
2161 | if (simplejump_p (insn)) | |
2162 | { | |
2163 | note = find_reg_note (insn, REG_BR_PROB, NULL); | |
2164 | if (note) | |
2165 | remove_note (insn, note); | |
2166 | while ((note = find_reg_note (insn, REG_BR_PRED, NULL))) | |
2167 | remove_note (insn, note); | |
2168 | } | |
2169 | ||
ca6c03ca JH |
2170 | for (e = bb->succ; e; e = next) |
2171 | { | |
2172 | next = e->succ_next; | |
2173 | ||
7fcd7218 JH |
2174 | /* Avoid abnormal flags to leak from computed jumps turned |
2175 | into simplejumps. */ | |
2176 | ||
0e1638d4 | 2177 | e->flags &= ~EDGE_ABNORMAL; |
7fcd7218 | 2178 | |
ca6c03ca JH |
2179 | /* Check purposes we can have edge. */ |
2180 | if ((e->flags & EDGE_FALLTHRU) | |
2181 | && any_condjump_p (insn)) | |
2182 | continue; | |
5f0d2358 RK |
2183 | else if (e->dest != EXIT_BLOCK_PTR |
2184 | && e->dest->head == JUMP_LABEL (insn)) | |
ca6c03ca | 2185 | continue; |
5f0d2358 RK |
2186 | else if (e->dest == EXIT_BLOCK_PTR |
2187 | && returnjump_p (insn)) | |
ca6c03ca | 2188 | continue; |
5f0d2358 | 2189 | |
c51d95ec | 2190 | bb->flags |= BB_DIRTY; |
ca6c03ca JH |
2191 | purged = true; |
2192 | remove_edge (e); | |
2193 | } | |
5f0d2358 | 2194 | |
ca6c03ca | 2195 | if (!bb->succ || !purged) |
c51d95ec | 2196 | return purged; |
5f0d2358 | 2197 | |
ca6c03ca JH |
2198 | if (rtl_dump_file) |
2199 | fprintf (rtl_dump_file, "Purged edges from bb %i\n", bb->index); | |
5f0d2358 | 2200 | |
ca6c03ca JH |
2201 | if (!optimize) |
2202 | return purged; | |
2203 | ||
2204 | /* Redistribute probabilities. */ | |
2205 | if (!bb->succ->succ_next) | |
2206 | { | |
2207 | bb->succ->probability = REG_BR_PROB_BASE; | |
2208 | bb->succ->count = bb->count; | |
2209 | } | |
2210 | else | |
2211 | { | |
2212 | note = find_reg_note (insn, REG_BR_PROB, NULL); | |
2213 | if (!note) | |
2214 | return purged; | |
5f0d2358 | 2215 | |
ca6c03ca JH |
2216 | b = BRANCH_EDGE (bb); |
2217 | f = FALLTHRU_EDGE (bb); | |
2218 | b->probability = INTVAL (XEXP (note, 0)); | |
2219 | f->probability = REG_BR_PROB_BASE - b->probability; | |
2220 | b->count = bb->count * b->probability / REG_BR_PROB_BASE; | |
2221 | f->count = bb->count * f->probability / REG_BR_PROB_BASE; | |
2222 | } | |
5f0d2358 | 2223 | |
ca6c03ca JH |
2224 | return purged; |
2225 | } | |
2226 | ||
ca6c03ca JH |
2227 | /* If we don't see a jump insn, we don't know exactly why the block would |
2228 | have been broken at this point. Look for a simple, non-fallthru edge, | |
2229 | as these are only created by conditional branches. If we find such an | |
2230 | edge we know that there used to be a jump here and can then safely | |
2231 | remove all non-fallthru edges. */ | |
2232 | for (e = bb->succ; e && (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)); | |
5f0d2358 RK |
2233 | e = e->succ_next) |
2234 | ; | |
2235 | ||
ca6c03ca JH |
2236 | if (!e) |
2237 | return purged; | |
5f0d2358 | 2238 | |
ca6c03ca JH |
2239 | for (e = bb->succ; e; e = next) |
2240 | { | |
2241 | next = e->succ_next; | |
2242 | if (!(e->flags & EDGE_FALLTHRU)) | |
c51d95ec JH |
2243 | { |
2244 | bb->flags |= BB_DIRTY; | |
2245 | remove_edge (e); | |
2246 | purged = true; | |
2247 | } | |
ca6c03ca | 2248 | } |
5f0d2358 | 2249 | |
ca6c03ca JH |
2250 | if (!bb->succ || bb->succ->succ_next) |
2251 | abort (); | |
5f0d2358 | 2252 | |
ca6c03ca JH |
2253 | bb->succ->probability = REG_BR_PROB_BASE; |
2254 | bb->succ->count = bb->count; | |
2255 | ||
2256 | if (rtl_dump_file) | |
2257 | fprintf (rtl_dump_file, "Purged non-fallthru edges from bb %i\n", | |
2258 | bb->index); | |
2259 | return purged; | |
2260 | } | |
2261 | ||
5f0d2358 RK |
2262 | /* Search all basic blocks for potentially dead edges and purge them. Return |
2263 | true if some edge has been eliminated. */ | |
ca6c03ca JH |
2264 | |
2265 | bool | |
473fb060 | 2266 | purge_all_dead_edges (update_life_p) |
00baba68 | 2267 | int update_life_p; |
ca6c03ca JH |
2268 | { |
2269 | int i, purged = false; | |
710af899 | 2270 | sbitmap blocks = 0; |
473fb060 JH |
2271 | |
2272 | if (update_life_p) | |
2273 | { | |
2274 | blocks = sbitmap_alloc (n_basic_blocks); | |
2275 | sbitmap_zero (blocks); | |
2276 | } | |
5f0d2358 | 2277 | |
ca6c03ca | 2278 | for (i = 0; i < n_basic_blocks; i++) |
473fb060 | 2279 | { |
5f0d2358 RK |
2280 | bool purged_here = purge_dead_edges (BASIC_BLOCK (i)); |
2281 | ||
473fb060 JH |
2282 | purged |= purged_here; |
2283 | if (purged_here && update_life_p) | |
2284 | SET_BIT (blocks, i); | |
2285 | } | |
5f0d2358 | 2286 | |
473fb060 JH |
2287 | if (update_life_p && purged) |
2288 | update_life_info (blocks, UPDATE_LIFE_GLOBAL, | |
2289 | PROP_DEATH_NOTES | PROP_SCAN_DEAD_CODE | |
2290 | | PROP_KILL_DEAD_CODE); | |
5f0d2358 | 2291 | |
473fb060 JH |
2292 | if (update_life_p) |
2293 | sbitmap_free (blocks); | |
ca6c03ca JH |
2294 | return purged; |
2295 | } |