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