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402209ff | 1 | /* Control flow graph analysis code for GNU compiler. |
818ab71a | 2 | Copyright (C) 1987-2016 Free Software Foundation, Inc. |
402209ff JH |
3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 8 | Software Foundation; either version 3, or (at your option) any later |
402209ff JH |
9 | version. |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 | for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
402209ff JH |
19 | |
20 | /* This file contains various simple utilities to analyze the CFG. */ | |
532aafad | 21 | |
402209ff JH |
22 | #include "config.h" |
23 | #include "system.h" | |
4977bab6 | 24 | #include "coretypes.h" |
c7131fb2 | 25 | #include "backend.h" |
957060b5 | 26 | #include "cfghooks.h" |
bd454efd | 27 | #include "timevar.h" |
957060b5 | 28 | #include "cfganal.h" |
402209ff JH |
29 | |
30 | /* Store the data structures necessary for depth-first search. */ | |
526ceb68 | 31 | struct depth_first_search_ds { |
402209ff JH |
32 | /* stack for backtracking during the algorithm */ |
33 | basic_block *stack; | |
34 | ||
35 | /* number of edges in the stack. That is, positions 0, ..., sp-1 | |
36 | have edges. */ | |
37 | unsigned int sp; | |
38 | ||
39 | /* record of basic blocks already seen by depth-first search */ | |
40 | sbitmap visited_blocks; | |
41 | }; | |
402209ff | 42 | |
526ceb68 TS |
43 | static void flow_dfs_compute_reverse_init (depth_first_search_ds *); |
44 | static void flow_dfs_compute_reverse_add_bb (depth_first_search_ds *, | |
d329e058 | 45 | basic_block); |
526ceb68 | 46 | static basic_block flow_dfs_compute_reverse_execute (depth_first_search_ds *, |
24c75ec6 | 47 | basic_block); |
526ceb68 | 48 | static void flow_dfs_compute_reverse_finish (depth_first_search_ds *); |
402209ff | 49 | \f |
402209ff | 50 | /* Mark the back edges in DFS traversal. |
da7d8304 | 51 | Return nonzero if a loop (natural or otherwise) is present. |
402209ff JH |
52 | Inspired by Depth_First_Search_PP described in: |
53 | ||
54 | Advanced Compiler Design and Implementation | |
55 | Steven Muchnick | |
56 | Morgan Kaufmann, 1997 | |
57 | ||
f91a0beb | 58 | and heavily borrowed from pre_and_rev_post_order_compute. */ |
402209ff JH |
59 | |
60 | bool | |
d329e058 | 61 | mark_dfs_back_edges (void) |
402209ff | 62 | { |
628f6a4e | 63 | edge_iterator *stack; |
402209ff JH |
64 | int *pre; |
65 | int *post; | |
66 | int sp; | |
67 | int prenum = 1; | |
68 | int postnum = 1; | |
69 | sbitmap visited; | |
70 | bool found = false; | |
71 | ||
72 | /* Allocate the preorder and postorder number arrays. */ | |
8b1c6fd7 DM |
73 | pre = XCNEWVEC (int, last_basic_block_for_fn (cfun)); |
74 | post = XCNEWVEC (int, last_basic_block_for_fn (cfun)); | |
402209ff JH |
75 | |
76 | /* Allocate stack for back-tracking up CFG. */ | |
0cae8d31 | 77 | stack = XNEWVEC (edge_iterator, n_basic_blocks_for_fn (cfun) + 1); |
402209ff JH |
78 | sp = 0; |
79 | ||
80 | /* Allocate bitmap to track nodes that have been visited. */ | |
8b1c6fd7 | 81 | visited = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
402209ff JH |
82 | |
83 | /* None of the nodes in the CFG have been visited yet. */ | |
f61e445a | 84 | bitmap_clear (visited); |
402209ff JH |
85 | |
86 | /* Push the first edge on to the stack. */ | |
fefa31b5 | 87 | stack[sp++] = ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs); |
402209ff JH |
88 | |
89 | while (sp) | |
90 | { | |
628f6a4e | 91 | edge_iterator ei; |
402209ff JH |
92 | basic_block src; |
93 | basic_block dest; | |
94 | ||
95 | /* Look at the edge on the top of the stack. */ | |
628f6a4e BE |
96 | ei = stack[sp - 1]; |
97 | src = ei_edge (ei)->src; | |
98 | dest = ei_edge (ei)->dest; | |
99 | ei_edge (ei)->flags &= ~EDGE_DFS_BACK; | |
402209ff JH |
100 | |
101 | /* Check if the edge destination has been visited yet. */ | |
fefa31b5 DM |
102 | if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun) && ! bitmap_bit_p (visited, |
103 | dest->index)) | |
402209ff JH |
104 | { |
105 | /* Mark that we have visited the destination. */ | |
d7c028c0 | 106 | bitmap_set_bit (visited, dest->index); |
402209ff | 107 | |
0b17ab2f | 108 | pre[dest->index] = prenum++; |
628f6a4e | 109 | if (EDGE_COUNT (dest->succs) > 0) |
402209ff JH |
110 | { |
111 | /* Since the DEST node has been visited for the first | |
112 | time, check its successors. */ | |
628f6a4e | 113 | stack[sp++] = ei_start (dest->succs); |
402209ff JH |
114 | } |
115 | else | |
0b17ab2f | 116 | post[dest->index] = postnum++; |
402209ff JH |
117 | } |
118 | else | |
119 | { | |
fefa31b5 DM |
120 | if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun) |
121 | && src != ENTRY_BLOCK_PTR_FOR_FN (cfun) | |
0b17ab2f RH |
122 | && pre[src->index] >= pre[dest->index] |
123 | && post[dest->index] == 0) | |
628f6a4e | 124 | ei_edge (ei)->flags |= EDGE_DFS_BACK, found = true; |
402209ff | 125 | |
fefa31b5 DM |
126 | if (ei_one_before_end_p (ei) |
127 | && src != ENTRY_BLOCK_PTR_FOR_FN (cfun)) | |
0b17ab2f | 128 | post[src->index] = postnum++; |
402209ff | 129 | |
628f6a4e BE |
130 | if (!ei_one_before_end_p (ei)) |
131 | ei_next (&stack[sp - 1]); | |
402209ff JH |
132 | else |
133 | sp--; | |
134 | } | |
135 | } | |
136 | ||
137 | free (pre); | |
138 | free (post); | |
139 | free (stack); | |
140 | sbitmap_free (visited); | |
141 | ||
142 | return found; | |
143 | } | |
144 | ||
402209ff | 145 | /* Find unreachable blocks. An unreachable block will have 0 in |
da7d8304 | 146 | the reachable bit in block->flags. A nonzero value indicates the |
402209ff JH |
147 | block is reachable. */ |
148 | ||
149 | void | |
d329e058 | 150 | find_unreachable_blocks (void) |
402209ff JH |
151 | { |
152 | edge e; | |
628f6a4e | 153 | edge_iterator ei; |
e0082a72 | 154 | basic_block *tos, *worklist, bb; |
402209ff | 155 | |
0cae8d31 | 156 | tos = worklist = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun)); |
402209ff JH |
157 | |
158 | /* Clear all the reachability flags. */ | |
159 | ||
11cd3bed | 160 | FOR_EACH_BB_FN (bb, cfun) |
e0082a72 | 161 | bb->flags &= ~BB_REACHABLE; |
402209ff JH |
162 | |
163 | /* Add our starting points to the worklist. Almost always there will | |
eaec9b3d | 164 | be only one. It isn't inconceivable that we might one day directly |
402209ff JH |
165 | support Fortran alternate entry points. */ |
166 | ||
fefa31b5 | 167 | FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs) |
402209ff JH |
168 | { |
169 | *tos++ = e->dest; | |
170 | ||
171 | /* Mark the block reachable. */ | |
172 | e->dest->flags |= BB_REACHABLE; | |
173 | } | |
174 | ||
175 | /* Iterate: find everything reachable from what we've already seen. */ | |
176 | ||
177 | while (tos != worklist) | |
178 | { | |
179 | basic_block b = *--tos; | |
180 | ||
628f6a4e | 181 | FOR_EACH_EDGE (e, ei, b->succs) |
0b612e0b JL |
182 | { |
183 | basic_block dest = e->dest; | |
184 | ||
185 | if (!(dest->flags & BB_REACHABLE)) | |
186 | { | |
187 | *tos++ = dest; | |
188 | dest->flags |= BB_REACHABLE; | |
189 | } | |
190 | } | |
402209ff JH |
191 | } |
192 | ||
193 | free (worklist); | |
194 | } | |
a352b710 TV |
195 | |
196 | /* Verify that there are no unreachable blocks in the current function. */ | |
197 | ||
198 | void | |
199 | verify_no_unreachable_blocks (void) | |
200 | { | |
201 | find_unreachable_blocks (); | |
202 | ||
203 | basic_block bb; | |
204 | FOR_EACH_BB_FN (bb, cfun) | |
205 | gcc_assert ((bb->flags & BB_REACHABLE) != 0); | |
206 | } | |
207 | ||
402209ff JH |
208 | \f |
209 | /* Functions to access an edge list with a vector representation. | |
210 | Enough data is kept such that given an index number, the | |
211 | pred and succ that edge represents can be determined, or | |
212 | given a pred and a succ, its index number can be returned. | |
213 | This allows algorithms which consume a lot of memory to | |
214 | represent the normally full matrix of edge (pred,succ) with a | |
215 | single indexed vector, edge (EDGE_INDEX (pred, succ)), with no | |
216 | wasted space in the client code due to sparse flow graphs. */ | |
217 | ||
218 | /* This functions initializes the edge list. Basically the entire | |
219 | flowgraph is processed, and all edges are assigned a number, | |
220 | and the data structure is filled in. */ | |
221 | ||
222 | struct edge_list * | |
d329e058 | 223 | create_edge_list (void) |
402209ff JH |
224 | { |
225 | struct edge_list *elist; | |
226 | edge e; | |
227 | int num_edges; | |
e0082a72 | 228 | basic_block bb; |
628f6a4e | 229 | edge_iterator ei; |
402209ff | 230 | |
402209ff JH |
231 | /* Determine the number of edges in the flow graph by counting successor |
232 | edges on each basic block. */ | |
532aafad | 233 | num_edges = 0; |
fefa31b5 DM |
234 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
235 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
402209ff | 236 | { |
628f6a4e | 237 | num_edges += EDGE_COUNT (bb->succs); |
402209ff | 238 | } |
4891442b | 239 | |
5ed6ace5 | 240 | elist = XNEW (struct edge_list); |
402209ff | 241 | elist->num_edges = num_edges; |
5ed6ace5 | 242 | elist->index_to_edge = XNEWVEC (edge, num_edges); |
402209ff JH |
243 | |
244 | num_edges = 0; | |
245 | ||
e0082a72 | 246 | /* Follow successors of blocks, and register these edges. */ |
fefa31b5 DM |
247 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
248 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
628f6a4e | 249 | FOR_EACH_EDGE (e, ei, bb->succs) |
e0082a72 | 250 | elist->index_to_edge[num_edges++] = e; |
4891442b | 251 | |
402209ff JH |
252 | return elist; |
253 | } | |
254 | ||
255 | /* This function free's memory associated with an edge list. */ | |
256 | ||
257 | void | |
d329e058 | 258 | free_edge_list (struct edge_list *elist) |
402209ff JH |
259 | { |
260 | if (elist) | |
261 | { | |
262 | free (elist->index_to_edge); | |
263 | free (elist); | |
264 | } | |
265 | } | |
266 | ||
267 | /* This function provides debug output showing an edge list. */ | |
268 | ||
24e47c76 | 269 | DEBUG_FUNCTION void |
d329e058 | 270 | print_edge_list (FILE *f, struct edge_list *elist) |
402209ff JH |
271 | { |
272 | int x; | |
4891442b | 273 | |
402209ff | 274 | fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n", |
0cae8d31 | 275 | n_basic_blocks_for_fn (cfun), elist->num_edges); |
402209ff JH |
276 | |
277 | for (x = 0; x < elist->num_edges; x++) | |
278 | { | |
279 | fprintf (f, " %-4d - edge(", x); | |
fefa31b5 | 280 | if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
402209ff JH |
281 | fprintf (f, "entry,"); |
282 | else | |
0b17ab2f | 283 | fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index); |
402209ff | 284 | |
fefa31b5 | 285 | if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
402209ff JH |
286 | fprintf (f, "exit)\n"); |
287 | else | |
0b17ab2f | 288 | fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index); |
402209ff JH |
289 | } |
290 | } | |
291 | ||
292 | /* This function provides an internal consistency check of an edge list, | |
293 | verifying that all edges are present, and that there are no | |
294 | extra edges. */ | |
295 | ||
24e47c76 | 296 | DEBUG_FUNCTION void |
d329e058 | 297 | verify_edge_list (FILE *f, struct edge_list *elist) |
402209ff | 298 | { |
e0082a72 | 299 | int pred, succ, index; |
402209ff | 300 | edge e; |
e0082a72 | 301 | basic_block bb, p, s; |
628f6a4e | 302 | edge_iterator ei; |
402209ff | 303 | |
fefa31b5 DM |
304 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
305 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
402209ff | 306 | { |
628f6a4e | 307 | FOR_EACH_EDGE (e, ei, bb->succs) |
402209ff | 308 | { |
0b17ab2f RH |
309 | pred = e->src->index; |
310 | succ = e->dest->index; | |
402209ff JH |
311 | index = EDGE_INDEX (elist, e->src, e->dest); |
312 | if (index == EDGE_INDEX_NO_EDGE) | |
313 | { | |
314 | fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ); | |
315 | continue; | |
316 | } | |
4891442b | 317 | |
0b17ab2f | 318 | if (INDEX_EDGE_PRED_BB (elist, index)->index != pred) |
402209ff | 319 | fprintf (f, "*p* Pred for index %d should be %d not %d\n", |
0b17ab2f RH |
320 | index, pred, INDEX_EDGE_PRED_BB (elist, index)->index); |
321 | if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ) | |
402209ff | 322 | fprintf (f, "*p* Succ for index %d should be %d not %d\n", |
0b17ab2f RH |
323 | index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index); |
324 | } | |
325 | } | |
326 | ||
e0082a72 | 327 | /* We've verified that all the edges are in the list, now lets make sure |
532aafad | 328 | there are no spurious edges in the list. This is an expensive check! */ |
402209ff | 329 | |
fefa31b5 DM |
330 | FOR_BB_BETWEEN (p, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
331 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
332 | FOR_BB_BETWEEN (s, ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb, NULL, next_bb) | |
402209ff | 333 | { |
402209ff JH |
334 | int found_edge = 0; |
335 | ||
628f6a4e | 336 | FOR_EACH_EDGE (e, ei, p->succs) |
402209ff JH |
337 | if (e->dest == s) |
338 | { | |
339 | found_edge = 1; | |
340 | break; | |
341 | } | |
4891442b | 342 | |
628f6a4e | 343 | FOR_EACH_EDGE (e, ei, s->preds) |
402209ff JH |
344 | if (e->src == p) |
345 | { | |
346 | found_edge = 1; | |
347 | break; | |
348 | } | |
4891442b | 349 | |
e0082a72 | 350 | if (EDGE_INDEX (elist, p, s) |
402209ff JH |
351 | == EDGE_INDEX_NO_EDGE && found_edge != 0) |
352 | fprintf (f, "*** Edge (%d, %d) appears to not have an index\n", | |
e0082a72 ZD |
353 | p->index, s->index); |
354 | if (EDGE_INDEX (elist, p, s) | |
402209ff JH |
355 | != EDGE_INDEX_NO_EDGE && found_edge == 0) |
356 | fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n", | |
e0082a72 | 357 | p->index, s->index, EDGE_INDEX (elist, p, s)); |
402209ff | 358 | } |
402209ff JH |
359 | } |
360 | ||
c8e9d8c3 RB |
361 | |
362 | /* Functions to compute control dependences. */ | |
363 | ||
364 | /* Indicate block BB is control dependent on an edge with index EDGE_INDEX. */ | |
365 | void | |
366 | control_dependences::set_control_dependence_map_bit (basic_block bb, | |
367 | int edge_index) | |
368 | { | |
fefa31b5 | 369 | if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
c8e9d8c3 | 370 | return; |
fefa31b5 | 371 | gcc_assert (bb != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
c8e9d8c3 RB |
372 | bitmap_set_bit (control_dependence_map[bb->index], edge_index); |
373 | } | |
374 | ||
375 | /* Clear all control dependences for block BB. */ | |
376 | void | |
377 | control_dependences::clear_control_dependence_bitmap (basic_block bb) | |
378 | { | |
379 | bitmap_clear (control_dependence_map[bb->index]); | |
380 | } | |
381 | ||
382 | /* Find the immediate postdominator PDOM of the specified basic block BLOCK. | |
383 | This function is necessary because some blocks have negative numbers. */ | |
384 | ||
385 | static inline basic_block | |
386 | find_pdom (basic_block block) | |
387 | { | |
fefa31b5 | 388 | gcc_assert (block != ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
c8e9d8c3 | 389 | |
fefa31b5 DM |
390 | if (block == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
391 | return EXIT_BLOCK_PTR_FOR_FN (cfun); | |
c8e9d8c3 RB |
392 | else |
393 | { | |
394 | basic_block bb = get_immediate_dominator (CDI_POST_DOMINATORS, block); | |
395 | if (! bb) | |
fefa31b5 | 396 | return EXIT_BLOCK_PTR_FOR_FN (cfun); |
c8e9d8c3 RB |
397 | return bb; |
398 | } | |
399 | } | |
400 | ||
401 | /* Determine all blocks' control dependences on the given edge with edge_list | |
402 | EL index EDGE_INDEX, ala Morgan, Section 3.6. */ | |
403 | ||
404 | void | |
405 | control_dependences::find_control_dependence (int edge_index) | |
406 | { | |
407 | basic_block current_block; | |
408 | basic_block ending_block; | |
409 | ||
fefa31b5 DM |
410 | gcc_assert (INDEX_EDGE_PRED_BB (m_el, edge_index) |
411 | != EXIT_BLOCK_PTR_FOR_FN (cfun)); | |
c8e9d8c3 | 412 | |
fefa31b5 DM |
413 | if (INDEX_EDGE_PRED_BB (m_el, edge_index) == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
414 | ending_block = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); | |
c8e9d8c3 | 415 | else |
65d3284b | 416 | ending_block = find_pdom (INDEX_EDGE_PRED_BB (m_el, edge_index)); |
c8e9d8c3 | 417 | |
65d3284b | 418 | for (current_block = INDEX_EDGE_SUCC_BB (m_el, edge_index); |
fefa31b5 DM |
419 | current_block != ending_block |
420 | && current_block != EXIT_BLOCK_PTR_FOR_FN (cfun); | |
c8e9d8c3 RB |
421 | current_block = find_pdom (current_block)) |
422 | { | |
65d3284b | 423 | edge e = INDEX_EDGE (m_el, edge_index); |
c8e9d8c3 RB |
424 | |
425 | /* For abnormal edges, we don't make current_block control | |
426 | dependent because instructions that throw are always necessary | |
427 | anyway. */ | |
428 | if (e->flags & EDGE_ABNORMAL) | |
429 | continue; | |
430 | ||
431 | set_control_dependence_map_bit (current_block, edge_index); | |
432 | } | |
433 | } | |
434 | ||
435 | /* Record all blocks' control dependences on all edges in the edge | |
436 | list EL, ala Morgan, Section 3.6. */ | |
437 | ||
438 | control_dependences::control_dependences (struct edge_list *edges) | |
65d3284b | 439 | : m_el (edges) |
c8e9d8c3 RB |
440 | { |
441 | timevar_push (TV_CONTROL_DEPENDENCES); | |
8b1c6fd7 DM |
442 | control_dependence_map.create (last_basic_block_for_fn (cfun)); |
443 | for (int i = 0; i < last_basic_block_for_fn (cfun); ++i) | |
c8e9d8c3 | 444 | control_dependence_map.quick_push (BITMAP_ALLOC (NULL)); |
65d3284b | 445 | for (int i = 0; i < NUM_EDGES (m_el); ++i) |
c8e9d8c3 RB |
446 | find_control_dependence (i); |
447 | timevar_pop (TV_CONTROL_DEPENDENCES); | |
448 | } | |
449 | ||
450 | /* Free control dependences and the associated edge list. */ | |
451 | ||
452 | control_dependences::~control_dependences () | |
453 | { | |
f23c0742 | 454 | for (unsigned i = 0; i < control_dependence_map.length (); ++i) |
c8e9d8c3 RB |
455 | BITMAP_FREE (control_dependence_map[i]); |
456 | control_dependence_map.release (); | |
65d3284b | 457 | free_edge_list (m_el); |
c8e9d8c3 RB |
458 | } |
459 | ||
460 | /* Returns the bitmap of edges the basic-block I is dependent on. */ | |
461 | ||
462 | bitmap | |
463 | control_dependences::get_edges_dependent_on (int i) | |
464 | { | |
465 | return control_dependence_map[i]; | |
466 | } | |
467 | ||
468 | /* Returns the edge with index I from the edge list. */ | |
469 | ||
470 | edge | |
471 | control_dependences::get_edge (int i) | |
472 | { | |
65d3284b | 473 | return INDEX_EDGE (m_el, i); |
c8e9d8c3 RB |
474 | } |
475 | ||
476 | ||
6de9cd9a DN |
477 | /* Given PRED and SUCC blocks, return the edge which connects the blocks. |
478 | If no such edge exists, return NULL. */ | |
479 | ||
480 | edge | |
481 | find_edge (basic_block pred, basic_block succ) | |
482 | { | |
483 | edge e; | |
628f6a4e | 484 | edge_iterator ei; |
6de9cd9a | 485 | |
df95526b JL |
486 | if (EDGE_COUNT (pred->succs) <= EDGE_COUNT (succ->preds)) |
487 | { | |
488 | FOR_EACH_EDGE (e, ei, pred->succs) | |
489 | if (e->dest == succ) | |
490 | return e; | |
491 | } | |
492 | else | |
493 | { | |
494 | FOR_EACH_EDGE (e, ei, succ->preds) | |
495 | if (e->src == pred) | |
496 | return e; | |
497 | } | |
6de9cd9a DN |
498 | |
499 | return NULL; | |
500 | } | |
501 | ||
402209ff JH |
502 | /* This routine will determine what, if any, edge there is between |
503 | a specified predecessor and successor. */ | |
504 | ||
505 | int | |
d329e058 | 506 | find_edge_index (struct edge_list *edge_list, basic_block pred, basic_block succ) |
402209ff JH |
507 | { |
508 | int x; | |
4891442b | 509 | |
402209ff | 510 | for (x = 0; x < NUM_EDGES (edge_list); x++) |
4891442b RK |
511 | if (INDEX_EDGE_PRED_BB (edge_list, x) == pred |
512 | && INDEX_EDGE_SUCC_BB (edge_list, x) == succ) | |
513 | return x; | |
514 | ||
402209ff JH |
515 | return (EDGE_INDEX_NO_EDGE); |
516 | } | |
402209ff | 517 | \f |
6809cbf9 RH |
518 | /* This routine will remove any fake predecessor edges for a basic block. |
519 | When the edge is removed, it is also removed from whatever successor | |
402209ff JH |
520 | list it is in. */ |
521 | ||
522 | static void | |
6809cbf9 | 523 | remove_fake_predecessors (basic_block bb) |
402209ff JH |
524 | { |
525 | edge e; | |
628f6a4e | 526 | edge_iterator ei; |
4891442b | 527 | |
628f6a4e | 528 | for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) |
402209ff | 529 | { |
628f6a4e BE |
530 | if ((e->flags & EDGE_FAKE) == EDGE_FAKE) |
531 | remove_edge (e); | |
532 | else | |
533 | ei_next (&ei); | |
402209ff JH |
534 | } |
535 | } | |
536 | ||
537 | /* This routine will remove all fake edges from the flow graph. If | |
538 | we remove all fake successors, it will automatically remove all | |
539 | fake predecessors. */ | |
540 | ||
541 | void | |
d329e058 | 542 | remove_fake_edges (void) |
402209ff | 543 | { |
e0082a72 | 544 | basic_block bb; |
402209ff | 545 | |
fefa31b5 | 546 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb, NULL, next_bb) |
6809cbf9 | 547 | remove_fake_predecessors (bb); |
402209ff JH |
548 | } |
549 | ||
6809cbf9 RH |
550 | /* This routine will remove all fake edges to the EXIT_BLOCK. */ |
551 | ||
552 | void | |
553 | remove_fake_exit_edges (void) | |
554 | { | |
fefa31b5 | 555 | remove_fake_predecessors (EXIT_BLOCK_PTR_FOR_FN (cfun)); |
6809cbf9 RH |
556 | } |
557 | ||
558 | ||
402209ff JH |
559 | /* This function will add a fake edge between any block which has no |
560 | successors, and the exit block. Some data flow equations require these | |
561 | edges to exist. */ | |
562 | ||
563 | void | |
d329e058 | 564 | add_noreturn_fake_exit_edges (void) |
402209ff | 565 | { |
e0082a72 | 566 | basic_block bb; |
402209ff | 567 | |
11cd3bed | 568 | FOR_EACH_BB_FN (bb, cfun) |
628f6a4e | 569 | if (EDGE_COUNT (bb->succs) == 0) |
fefa31b5 | 570 | make_single_succ_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun), EDGE_FAKE); |
402209ff JH |
571 | } |
572 | ||
573 | /* This function adds a fake edge between any infinite loops to the | |
574 | exit block. Some optimizations require a path from each node to | |
575 | the exit node. | |
576 | ||
577 | See also Morgan, Figure 3.10, pp. 82-83. | |
578 | ||
579 | The current implementation is ugly, not attempting to minimize the | |
580 | number of inserted fake edges. To reduce the number of fake edges | |
581 | to insert, add fake edges from _innermost_ loops containing only | |
582 | nodes not reachable from the exit block. */ | |
583 | ||
584 | void | |
d329e058 | 585 | connect_infinite_loops_to_exit (void) |
402209ff | 586 | { |
fefa31b5 | 587 | basic_block unvisited_block = EXIT_BLOCK_PTR_FOR_FN (cfun); |
d7bd989c | 588 | basic_block deadend_block; |
526ceb68 | 589 | depth_first_search_ds dfs_ds; |
402209ff JH |
590 | |
591 | /* Perform depth-first search in the reverse graph to find nodes | |
592 | reachable from the exit block. */ | |
402209ff | 593 | flow_dfs_compute_reverse_init (&dfs_ds); |
fefa31b5 | 594 | flow_dfs_compute_reverse_add_bb (&dfs_ds, EXIT_BLOCK_PTR_FOR_FN (cfun)); |
402209ff JH |
595 | |
596 | /* Repeatedly add fake edges, updating the unreachable nodes. */ | |
597 | while (1) | |
598 | { | |
24c75ec6 JL |
599 | unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds, |
600 | unvisited_block); | |
402209ff JH |
601 | if (!unvisited_block) |
602 | break; | |
4891442b | 603 | |
d7bd989c | 604 | deadend_block = dfs_find_deadend (unvisited_block); |
fefa31b5 | 605 | make_edge (deadend_block, EXIT_BLOCK_PTR_FOR_FN (cfun), EDGE_FAKE); |
d7bd989c | 606 | flow_dfs_compute_reverse_add_bb (&dfs_ds, deadend_block); |
402209ff JH |
607 | } |
608 | ||
609 | flow_dfs_compute_reverse_finish (&dfs_ds); | |
402209ff JH |
610 | return; |
611 | } | |
612 | \f | |
6fb5fa3c | 613 | /* Compute reverse top sort order. This is computing a post order |
dd5a833e | 614 | numbering of the graph. If INCLUDE_ENTRY_EXIT is true, then |
6fb5fa3c DB |
615 | ENTRY_BLOCK and EXIT_BLOCK are included. If DELETE_UNREACHABLE is |
616 | true, unreachable blocks are deleted. */ | |
4891442b | 617 | |
f91a0beb | 618 | int |
b8698a0f | 619 | post_order_compute (int *post_order, bool include_entry_exit, |
6fb5fa3c | 620 | bool delete_unreachable) |
402209ff | 621 | { |
628f6a4e | 622 | edge_iterator *stack; |
402209ff | 623 | int sp; |
f91a0beb | 624 | int post_order_num = 0; |
402209ff | 625 | sbitmap visited; |
6fb5fa3c | 626 | int count; |
402209ff | 627 | |
f91a0beb KZ |
628 | if (include_entry_exit) |
629 | post_order[post_order_num++] = EXIT_BLOCK; | |
630 | ||
402209ff | 631 | /* Allocate stack for back-tracking up CFG. */ |
0cae8d31 | 632 | stack = XNEWVEC (edge_iterator, n_basic_blocks_for_fn (cfun) + 1); |
402209ff JH |
633 | sp = 0; |
634 | ||
635 | /* Allocate bitmap to track nodes that have been visited. */ | |
8b1c6fd7 | 636 | visited = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
402209ff JH |
637 | |
638 | /* None of the nodes in the CFG have been visited yet. */ | |
f61e445a | 639 | bitmap_clear (visited); |
402209ff JH |
640 | |
641 | /* Push the first edge on to the stack. */ | |
fefa31b5 | 642 | stack[sp++] = ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs); |
402209ff JH |
643 | |
644 | while (sp) | |
645 | { | |
628f6a4e | 646 | edge_iterator ei; |
402209ff JH |
647 | basic_block src; |
648 | basic_block dest; | |
649 | ||
650 | /* Look at the edge on the top of the stack. */ | |
628f6a4e BE |
651 | ei = stack[sp - 1]; |
652 | src = ei_edge (ei)->src; | |
653 | dest = ei_edge (ei)->dest; | |
402209ff JH |
654 | |
655 | /* Check if the edge destination has been visited yet. */ | |
fefa31b5 DM |
656 | if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun) |
657 | && ! bitmap_bit_p (visited, dest->index)) | |
402209ff JH |
658 | { |
659 | /* Mark that we have visited the destination. */ | |
d7c028c0 | 660 | bitmap_set_bit (visited, dest->index); |
402209ff | 661 | |
628f6a4e | 662 | if (EDGE_COUNT (dest->succs) > 0) |
4891442b RK |
663 | /* Since the DEST node has been visited for the first |
664 | time, check its successors. */ | |
628f6a4e | 665 | stack[sp++] = ei_start (dest->succs); |
402209ff | 666 | else |
f91a0beb | 667 | post_order[post_order_num++] = dest->index; |
402209ff JH |
668 | } |
669 | else | |
670 | { | |
fefa31b5 DM |
671 | if (ei_one_before_end_p (ei) |
672 | && src != ENTRY_BLOCK_PTR_FOR_FN (cfun)) | |
6fb5fa3c | 673 | post_order[post_order_num++] = src->index; |
402209ff | 674 | |
628f6a4e BE |
675 | if (!ei_one_before_end_p (ei)) |
676 | ei_next (&stack[sp - 1]); | |
402209ff JH |
677 | else |
678 | sp--; | |
679 | } | |
680 | } | |
681 | ||
f91a0beb | 682 | if (include_entry_exit) |
6fb5fa3c DB |
683 | { |
684 | post_order[post_order_num++] = ENTRY_BLOCK; | |
685 | count = post_order_num; | |
686 | } | |
b8698a0f | 687 | else |
6fb5fa3c | 688 | count = post_order_num + 2; |
b8698a0f | 689 | |
6fb5fa3c DB |
690 | /* Delete the unreachable blocks if some were found and we are |
691 | supposed to do it. */ | |
0cae8d31 | 692 | if (delete_unreachable && (count != n_basic_blocks_for_fn (cfun))) |
6fb5fa3c DB |
693 | { |
694 | basic_block b; | |
695 | basic_block next_bb; | |
fefa31b5 DM |
696 | for (b = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; b |
697 | != EXIT_BLOCK_PTR_FOR_FN (cfun); b = next_bb) | |
6fb5fa3c DB |
698 | { |
699 | next_bb = b->next_bb; | |
b8698a0f | 700 | |
d7c028c0 | 701 | if (!(bitmap_bit_p (visited, b->index))) |
6fb5fa3c DB |
702 | delete_basic_block (b); |
703 | } | |
b8698a0f | 704 | |
6fb5fa3c DB |
705 | tidy_fallthru_edges (); |
706 | } | |
707 | ||
708 | free (stack); | |
709 | sbitmap_free (visited); | |
710 | return post_order_num; | |
711 | } | |
712 | ||
713 | ||
03b06a83 SB |
714 | /* Helper routine for inverted_post_order_compute |
715 | flow_dfs_compute_reverse_execute, and the reverse-CFG | |
716 | deapth first search in dominance.c. | |
6fb5fa3c DB |
717 | BB has to belong to a region of CFG |
718 | unreachable by inverted traversal from the exit. | |
719 | i.e. there's no control flow path from ENTRY to EXIT | |
720 | that contains this BB. | |
721 | This can happen in two cases - if there's an infinite loop | |
722 | or if there's a block that has no successor | |
723 | (call to a function with no return). | |
b8698a0f L |
724 | Some RTL passes deal with this condition by |
725 | calling connect_infinite_loops_to_exit () and/or | |
6fb5fa3c DB |
726 | add_noreturn_fake_exit_edges (). |
727 | However, those methods involve modifying the CFG itself | |
728 | which may not be desirable. | |
729 | Hence, we deal with the infinite loop/no return cases | |
730 | by identifying a unique basic block that can reach all blocks | |
731 | in such a region by inverted traversal. | |
732 | This function returns a basic block that guarantees | |
733 | that all blocks in the region are reachable | |
734 | by starting an inverted traversal from the returned block. */ | |
735 | ||
03b06a83 | 736 | basic_block |
6fb5fa3c DB |
737 | dfs_find_deadend (basic_block bb) |
738 | { | |
03b06a83 | 739 | bitmap visited = BITMAP_ALLOC (NULL); |
6fb5fa3c DB |
740 | |
741 | for (;;) | |
742 | { | |
6fb5fa3c | 743 | if (EDGE_COUNT (bb->succs) == 0 |
03b06a83 | 744 | || ! bitmap_set_bit (visited, bb->index)) |
6fb5fa3c | 745 | { |
03b06a83 | 746 | BITMAP_FREE (visited); |
6fb5fa3c DB |
747 | return bb; |
748 | } | |
749 | ||
750 | bb = EDGE_SUCC (bb, 0)->dest; | |
751 | } | |
752 | ||
753 | gcc_unreachable (); | |
754 | } | |
755 | ||
756 | ||
757 | /* Compute the reverse top sort order of the inverted CFG | |
758 | i.e. starting from the exit block and following the edges backward | |
759 | (from successors to predecessors). | |
760 | This ordering can be used for forward dataflow problems among others. | |
761 | ||
e4dbb0d4 JH |
762 | Optionally if START_POINTS is specified, start from exit block and all |
763 | basic blocks in START_POINTS. This is used by CD-DCE. | |
764 | ||
6fb5fa3c DB |
765 | This function assumes that all blocks in the CFG are reachable |
766 | from the ENTRY (but not necessarily from EXIT). | |
767 | ||
768 | If there's an infinite loop, | |
769 | a simple inverted traversal starting from the blocks | |
770 | with no successors can't visit all blocks. | |
771 | To solve this problem, we first do inverted traversal | |
772 | starting from the blocks with no successor. | |
b8698a0f | 773 | And if there's any block left that's not visited by the regular |
6fb5fa3c DB |
774 | inverted traversal from EXIT, |
775 | those blocks are in such problematic region. | |
b8698a0f | 776 | Among those, we find one block that has |
6fb5fa3c | 777 | any visited predecessor (which is an entry into such a region), |
b8698a0f | 778 | and start looking for a "dead end" from that block |
6fb5fa3c DB |
779 | and do another inverted traversal from that block. */ |
780 | ||
781 | int | |
e4dbb0d4 JH |
782 | inverted_post_order_compute (int *post_order, |
783 | sbitmap *start_points) | |
6fb5fa3c DB |
784 | { |
785 | basic_block bb; | |
786 | edge_iterator *stack; | |
787 | int sp; | |
788 | int post_order_num = 0; | |
789 | sbitmap visited; | |
790 | ||
a6c764d0 MM |
791 | if (flag_checking) |
792 | verify_no_unreachable_blocks (); | |
a352b710 | 793 | |
6fb5fa3c | 794 | /* Allocate stack for back-tracking up CFG. */ |
0cae8d31 | 795 | stack = XNEWVEC (edge_iterator, n_basic_blocks_for_fn (cfun) + 1); |
6fb5fa3c DB |
796 | sp = 0; |
797 | ||
798 | /* Allocate bitmap to track nodes that have been visited. */ | |
8b1c6fd7 | 799 | visited = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
6fb5fa3c DB |
800 | |
801 | /* None of the nodes in the CFG have been visited yet. */ | |
f61e445a | 802 | bitmap_clear (visited); |
6fb5fa3c | 803 | |
e4dbb0d4 JH |
804 | if (start_points) |
805 | { | |
806 | FOR_ALL_BB_FN (bb, cfun) | |
807 | if (bitmap_bit_p (*start_points, bb->index) | |
808 | && EDGE_COUNT (bb->preds) > 0) | |
809 | { | |
810 | stack[sp++] = ei_start (bb->preds); | |
811 | bitmap_set_bit (visited, bb->index); | |
812 | } | |
813 | if (EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds)) | |
814 | { | |
815 | stack[sp++] = ei_start (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds); | |
816 | bitmap_set_bit (visited, EXIT_BLOCK_PTR_FOR_FN (cfun)->index); | |
817 | } | |
818 | } | |
819 | else | |
6fb5fa3c | 820 | /* Put all blocks that have no successor into the initial work list. */ |
04a90bec | 821 | FOR_ALL_BB_FN (bb, cfun) |
6fb5fa3c DB |
822 | if (EDGE_COUNT (bb->succs) == 0) |
823 | { | |
824 | /* Push the initial edge on to the stack. */ | |
b8698a0f | 825 | if (EDGE_COUNT (bb->preds) > 0) |
6fb5fa3c DB |
826 | { |
827 | stack[sp++] = ei_start (bb->preds); | |
d7c028c0 | 828 | bitmap_set_bit (visited, bb->index); |
6fb5fa3c DB |
829 | } |
830 | } | |
831 | ||
b8698a0f | 832 | do |
6fb5fa3c DB |
833 | { |
834 | bool has_unvisited_bb = false; | |
835 | ||
836 | /* The inverted traversal loop. */ | |
837 | while (sp) | |
838 | { | |
839 | edge_iterator ei; | |
840 | basic_block pred; | |
841 | ||
842 | /* Look at the edge on the top of the stack. */ | |
843 | ei = stack[sp - 1]; | |
844 | bb = ei_edge (ei)->dest; | |
845 | pred = ei_edge (ei)->src; | |
846 | ||
847 | /* Check if the predecessor has been visited yet. */ | |
d7c028c0 | 848 | if (! bitmap_bit_p (visited, pred->index)) |
6fb5fa3c DB |
849 | { |
850 | /* Mark that we have visited the destination. */ | |
d7c028c0 | 851 | bitmap_set_bit (visited, pred->index); |
6fb5fa3c DB |
852 | |
853 | if (EDGE_COUNT (pred->preds) > 0) | |
854 | /* Since the predecessor node has been visited for the first | |
855 | time, check its predecessors. */ | |
856 | stack[sp++] = ei_start (pred->preds); | |
857 | else | |
858 | post_order[post_order_num++] = pred->index; | |
859 | } | |
860 | else | |
861 | { | |
fefa31b5 DM |
862 | if (bb != EXIT_BLOCK_PTR_FOR_FN (cfun) |
863 | && ei_one_before_end_p (ei)) | |
6fb5fa3c DB |
864 | post_order[post_order_num++] = bb->index; |
865 | ||
866 | if (!ei_one_before_end_p (ei)) | |
867 | ei_next (&stack[sp - 1]); | |
868 | else | |
869 | sp--; | |
870 | } | |
871 | } | |
872 | ||
b8698a0f | 873 | /* Detect any infinite loop and activate the kludge. |
6fb5fa3c DB |
874 | Note that this doesn't check EXIT_BLOCK itself |
875 | since EXIT_BLOCK is always added after the outer do-while loop. */ | |
fefa31b5 DM |
876 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
877 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
d7c028c0 | 878 | if (!bitmap_bit_p (visited, bb->index)) |
6fb5fa3c DB |
879 | { |
880 | has_unvisited_bb = true; | |
881 | ||
882 | if (EDGE_COUNT (bb->preds) > 0) | |
883 | { | |
884 | edge_iterator ei; | |
885 | edge e; | |
886 | basic_block visited_pred = NULL; | |
887 | ||
888 | /* Find an already visited predecessor. */ | |
889 | FOR_EACH_EDGE (e, ei, bb->preds) | |
890 | { | |
d7c028c0 | 891 | if (bitmap_bit_p (visited, e->src->index)) |
6fb5fa3c DB |
892 | visited_pred = e->src; |
893 | } | |
894 | ||
895 | if (visited_pred) | |
896 | { | |
897 | basic_block be = dfs_find_deadend (bb); | |
898 | gcc_assert (be != NULL); | |
d7c028c0 | 899 | bitmap_set_bit (visited, be->index); |
6fb5fa3c DB |
900 | stack[sp++] = ei_start (be->preds); |
901 | break; | |
902 | } | |
903 | } | |
904 | } | |
905 | ||
906 | if (has_unvisited_bb && sp == 0) | |
907 | { | |
b8698a0f | 908 | /* No blocks are reachable from EXIT at all. |
6fb5fa3c | 909 | Find a dead-end from the ENTRY, and restart the iteration. */ |
fefa31b5 | 910 | basic_block be = dfs_find_deadend (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
6fb5fa3c | 911 | gcc_assert (be != NULL); |
d7c028c0 | 912 | bitmap_set_bit (visited, be->index); |
6fb5fa3c DB |
913 | stack[sp++] = ei_start (be->preds); |
914 | } | |
915 | ||
b8698a0f | 916 | /* The only case the below while fires is |
6fb5fa3c DB |
917 | when there's an infinite loop. */ |
918 | } | |
919 | while (sp); | |
920 | ||
921 | /* EXIT_BLOCK is always included. */ | |
922 | post_order[post_order_num++] = EXIT_BLOCK; | |
f91a0beb | 923 | |
402209ff JH |
924 | free (stack); |
925 | sbitmap_free (visited); | |
f91a0beb | 926 | return post_order_num; |
402209ff JH |
927 | } |
928 | ||
1bef9b23 RB |
929 | /* Compute the depth first search order of FN and store in the array |
930 | PRE_ORDER if nonzero. If REV_POST_ORDER is nonzero, return the | |
931 | reverse completion number for each node. Returns the number of nodes | |
932 | visited. A depth first search tries to get as far away from the starting | |
933 | point as quickly as possible. | |
f91a0beb | 934 | |
1bef9b23 RB |
935 | In case the function has unreachable blocks the number of nodes |
936 | visited does not include them. | |
937 | ||
938 | pre_order is a really a preorder numbering of the graph. | |
939 | rev_post_order is really a reverse postorder numbering of the graph. */ | |
402209ff JH |
940 | |
941 | int | |
1bef9b23 RB |
942 | pre_and_rev_post_order_compute_fn (struct function *fn, |
943 | int *pre_order, int *rev_post_order, | |
944 | bool include_entry_exit) | |
402209ff | 945 | { |
628f6a4e | 946 | edge_iterator *stack; |
402209ff | 947 | int sp; |
f91a0beb | 948 | int pre_order_num = 0; |
0cae8d31 | 949 | int rev_post_order_num = n_basic_blocks_for_fn (cfun) - 1; |
402209ff JH |
950 | sbitmap visited; |
951 | ||
952 | /* Allocate stack for back-tracking up CFG. */ | |
0cae8d31 | 953 | stack = XNEWVEC (edge_iterator, n_basic_blocks_for_fn (cfun) + 1); |
402209ff JH |
954 | sp = 0; |
955 | ||
f91a0beb KZ |
956 | if (include_entry_exit) |
957 | { | |
958 | if (pre_order) | |
959 | pre_order[pre_order_num] = ENTRY_BLOCK; | |
960 | pre_order_num++; | |
961 | if (rev_post_order) | |
e5f95b66 | 962 | rev_post_order[rev_post_order_num--] = EXIT_BLOCK; |
f91a0beb | 963 | } |
b8698a0f | 964 | else |
f91a0beb KZ |
965 | rev_post_order_num -= NUM_FIXED_BLOCKS; |
966 | ||
402209ff | 967 | /* Allocate bitmap to track nodes that have been visited. */ |
8b1c6fd7 | 968 | visited = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
402209ff JH |
969 | |
970 | /* None of the nodes in the CFG have been visited yet. */ | |
f61e445a | 971 | bitmap_clear (visited); |
402209ff JH |
972 | |
973 | /* Push the first edge on to the stack. */ | |
fefa31b5 | 974 | stack[sp++] = ei_start (ENTRY_BLOCK_PTR_FOR_FN (fn)->succs); |
402209ff JH |
975 | |
976 | while (sp) | |
977 | { | |
628f6a4e | 978 | edge_iterator ei; |
402209ff JH |
979 | basic_block src; |
980 | basic_block dest; | |
981 | ||
982 | /* Look at the edge on the top of the stack. */ | |
628f6a4e BE |
983 | ei = stack[sp - 1]; |
984 | src = ei_edge (ei)->src; | |
985 | dest = ei_edge (ei)->dest; | |
402209ff JH |
986 | |
987 | /* Check if the edge destination has been visited yet. */ | |
fefa31b5 | 988 | if (dest != EXIT_BLOCK_PTR_FOR_FN (fn) |
1bef9b23 | 989 | && ! bitmap_bit_p (visited, dest->index)) |
402209ff JH |
990 | { |
991 | /* Mark that we have visited the destination. */ | |
d7c028c0 | 992 | bitmap_set_bit (visited, dest->index); |
402209ff | 993 | |
f91a0beb KZ |
994 | if (pre_order) |
995 | pre_order[pre_order_num] = dest->index; | |
f5f53ae3 | 996 | |
f91a0beb | 997 | pre_order_num++; |
402209ff | 998 | |
628f6a4e | 999 | if (EDGE_COUNT (dest->succs) > 0) |
4891442b RK |
1000 | /* Since the DEST node has been visited for the first |
1001 | time, check its successors. */ | |
628f6a4e | 1002 | stack[sp++] = ei_start (dest->succs); |
f91a0beb | 1003 | else if (rev_post_order) |
4891442b RK |
1004 | /* There are no successors for the DEST node so assign |
1005 | its reverse completion number. */ | |
f91a0beb | 1006 | rev_post_order[rev_post_order_num--] = dest->index; |
402209ff JH |
1007 | } |
1008 | else | |
1009 | { | |
1bef9b23 | 1010 | if (ei_one_before_end_p (ei) |
fefa31b5 | 1011 | && src != ENTRY_BLOCK_PTR_FOR_FN (fn) |
f91a0beb | 1012 | && rev_post_order) |
4891442b RK |
1013 | /* There are no more successors for the SRC node |
1014 | so assign its reverse completion number. */ | |
f91a0beb | 1015 | rev_post_order[rev_post_order_num--] = src->index; |
402209ff | 1016 | |
628f6a4e BE |
1017 | if (!ei_one_before_end_p (ei)) |
1018 | ei_next (&stack[sp - 1]); | |
402209ff JH |
1019 | else |
1020 | sp--; | |
1021 | } | |
1022 | } | |
1023 | ||
1024 | free (stack); | |
1025 | sbitmap_free (visited); | |
1026 | ||
f91a0beb KZ |
1027 | if (include_entry_exit) |
1028 | { | |
1029 | if (pre_order) | |
1030 | pre_order[pre_order_num] = EXIT_BLOCK; | |
1031 | pre_order_num++; | |
1032 | if (rev_post_order) | |
e5f95b66 | 1033 | rev_post_order[rev_post_order_num--] = ENTRY_BLOCK; |
f91a0beb | 1034 | } |
1bef9b23 RB |
1035 | |
1036 | return pre_order_num; | |
1037 | } | |
1038 | ||
1039 | /* Like pre_and_rev_post_order_compute_fn but operating on the | |
1040 | current function and asserting that all nodes were visited. */ | |
1041 | ||
1042 | int | |
1043 | pre_and_rev_post_order_compute (int *pre_order, int *rev_post_order, | |
1044 | bool include_entry_exit) | |
1045 | { | |
1046 | int pre_order_num | |
1047 | = pre_and_rev_post_order_compute_fn (cfun, pre_order, rev_post_order, | |
1048 | include_entry_exit); | |
1049 | if (include_entry_exit) | |
1050 | /* The number of nodes visited should be the number of blocks. */ | |
0cae8d31 | 1051 | gcc_assert (pre_order_num == n_basic_blocks_for_fn (cfun)); |
f91a0beb KZ |
1052 | else |
1053 | /* The number of nodes visited should be the number of blocks minus | |
1054 | the entry and exit blocks which are not visited here. */ | |
0cae8d31 DM |
1055 | gcc_assert (pre_order_num |
1056 | == (n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS)); | |
4891442b | 1057 | |
f91a0beb | 1058 | return pre_order_num; |
402209ff JH |
1059 | } |
1060 | ||
1061 | /* Compute the depth first search order on the _reverse_ graph and | |
1062 | store in the array DFS_ORDER, marking the nodes visited in VISITED. | |
1063 | Returns the number of nodes visited. | |
1064 | ||
1065 | The computation is split into three pieces: | |
1066 | ||
1067 | flow_dfs_compute_reverse_init () creates the necessary data | |
1068 | structures. | |
1069 | ||
1070 | flow_dfs_compute_reverse_add_bb () adds a basic block to the data | |
1071 | structures. The block will start the search. | |
1072 | ||
1073 | flow_dfs_compute_reverse_execute () continues (or starts) the | |
1074 | search using the block on the top of the stack, stopping when the | |
1075 | stack is empty. | |
1076 | ||
1077 | flow_dfs_compute_reverse_finish () destroys the necessary data | |
1078 | structures. | |
1079 | ||
1080 | Thus, the user will probably call ..._init(), call ..._add_bb() to | |
1081 | add a beginning basic block to the stack, call ..._execute(), | |
1082 | possibly add another bb to the stack and again call ..._execute(), | |
1083 | ..., and finally call _finish(). */ | |
1084 | ||
1085 | /* Initialize the data structures used for depth-first search on the | |
1086 | reverse graph. If INITIALIZE_STACK is nonzero, the exit block is | |
1087 | added to the basic block stack. DATA is the current depth-first | |
da7d8304 | 1088 | search context. If INITIALIZE_STACK is nonzero, there is an |
402209ff JH |
1089 | element on the stack. */ |
1090 | ||
1091 | static void | |
526ceb68 | 1092 | flow_dfs_compute_reverse_init (depth_first_search_ds *data) |
402209ff JH |
1093 | { |
1094 | /* Allocate stack for back-tracking up CFG. */ | |
0cae8d31 | 1095 | data->stack = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun)); |
402209ff JH |
1096 | data->sp = 0; |
1097 | ||
1098 | /* Allocate bitmap to track nodes that have been visited. */ | |
8b1c6fd7 | 1099 | data->visited_blocks = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
402209ff JH |
1100 | |
1101 | /* None of the nodes in the CFG have been visited yet. */ | |
f61e445a | 1102 | bitmap_clear (data->visited_blocks); |
402209ff JH |
1103 | |
1104 | return; | |
1105 | } | |
1106 | ||
1107 | /* Add the specified basic block to the top of the dfs data | |
1108 | structures. When the search continues, it will start at the | |
1109 | block. */ | |
1110 | ||
1111 | static void | |
526ceb68 | 1112 | flow_dfs_compute_reverse_add_bb (depth_first_search_ds *data, basic_block bb) |
402209ff JH |
1113 | { |
1114 | data->stack[data->sp++] = bb; | |
d7c028c0 | 1115 | bitmap_set_bit (data->visited_blocks, bb->index); |
402209ff JH |
1116 | } |
1117 | ||
4891442b RK |
1118 | /* Continue the depth-first search through the reverse graph starting with the |
1119 | block at the stack's top and ending when the stack is empty. Visited nodes | |
1120 | are marked. Returns an unvisited basic block, or NULL if there is none | |
1121 | available. */ | |
402209ff JH |
1122 | |
1123 | static basic_block | |
526ceb68 | 1124 | flow_dfs_compute_reverse_execute (depth_first_search_ds *data, |
24c75ec6 | 1125 | basic_block last_unvisited) |
402209ff JH |
1126 | { |
1127 | basic_block bb; | |
1128 | edge e; | |
628f6a4e | 1129 | edge_iterator ei; |
402209ff JH |
1130 | |
1131 | while (data->sp > 0) | |
1132 | { | |
1133 | bb = data->stack[--data->sp]; | |
4891442b | 1134 | |
db4a8254 | 1135 | /* Perform depth-first search on adjacent vertices. */ |
628f6a4e | 1136 | FOR_EACH_EDGE (e, ei, bb->preds) |
d7c028c0 | 1137 | if (!bitmap_bit_p (data->visited_blocks, e->src->index)) |
db4a8254 | 1138 | flow_dfs_compute_reverse_add_bb (data, e->src); |
402209ff JH |
1139 | } |
1140 | ||
1141 | /* Determine if there are unvisited basic blocks. */ | |
24c75ec6 | 1142 | FOR_BB_BETWEEN (bb, last_unvisited, NULL, prev_bb) |
d7c028c0 | 1143 | if (!bitmap_bit_p (data->visited_blocks, bb->index)) |
d7bd989c | 1144 | return bb; |
4891442b | 1145 | |
402209ff JH |
1146 | return NULL; |
1147 | } | |
1148 | ||
1149 | /* Destroy the data structures needed for depth-first search on the | |
1150 | reverse graph. */ | |
1151 | ||
1152 | static void | |
526ceb68 | 1153 | flow_dfs_compute_reverse_finish (depth_first_search_ds *data) |
402209ff JH |
1154 | { |
1155 | free (data->stack); | |
1156 | sbitmap_free (data->visited_blocks); | |
402209ff | 1157 | } |
2ecfd709 ZD |
1158 | |
1159 | /* Performs dfs search from BB over vertices satisfying PREDICATE; | |
1160 | if REVERSE, go against direction of edges. Returns number of blocks | |
1161 | found and their list in RSLT. RSLT can contain at most RSLT_MAX items. */ | |
1162 | int | |
d329e058 | 1163 | dfs_enumerate_from (basic_block bb, int reverse, |
ed7a4b4b KG |
1164 | bool (*predicate) (const_basic_block, const void *), |
1165 | basic_block *rslt, int rslt_max, const void *data) | |
2ecfd709 ZD |
1166 | { |
1167 | basic_block *st, lbb; | |
1168 | int sp = 0, tv = 0; | |
9e32d2be ZD |
1169 | unsigned size; |
1170 | ||
1171 | /* A bitmap to keep track of visited blocks. Allocating it each time | |
1172 | this function is called is not possible, since dfs_enumerate_from | |
1173 | is often used on small (almost) disjoint parts of cfg (bodies of | |
1174 | loops), and allocating a large sbitmap would lead to quadratic | |
1175 | behavior. */ | |
1176 | static sbitmap visited; | |
1177 | static unsigned v_size; | |
1178 | ||
d7c028c0 LC |
1179 | #define MARK_VISITED(BB) (bitmap_set_bit (visited, (BB)->index)) |
1180 | #define UNMARK_VISITED(BB) (bitmap_clear_bit (visited, (BB)->index)) | |
1181 | #define VISITED_P(BB) (bitmap_bit_p (visited, (BB)->index)) | |
9e32d2be ZD |
1182 | |
1183 | /* Resize the VISITED sbitmap if necessary. */ | |
8b1c6fd7 | 1184 | size = last_basic_block_for_fn (cfun); |
9e32d2be ZD |
1185 | if (size < 10) |
1186 | size = 10; | |
1187 | ||
1188 | if (!visited) | |
1189 | { | |
1190 | ||
1191 | visited = sbitmap_alloc (size); | |
f61e445a | 1192 | bitmap_clear (visited); |
9e32d2be ZD |
1193 | v_size = size; |
1194 | } | |
1195 | else if (v_size < size) | |
1196 | { | |
1197 | /* Ensure that we increase the size of the sbitmap exponentially. */ | |
1198 | if (2 * v_size > size) | |
1199 | size = 2 * v_size; | |
1200 | ||
1201 | visited = sbitmap_resize (visited, size, 0); | |
1202 | v_size = size; | |
1203 | } | |
2ecfd709 | 1204 | |
c302207e | 1205 | st = XNEWVEC (basic_block, rslt_max); |
2ecfd709 | 1206 | rslt[tv++] = st[sp++] = bb; |
9e32d2be | 1207 | MARK_VISITED (bb); |
2ecfd709 ZD |
1208 | while (sp) |
1209 | { | |
1210 | edge e; | |
628f6a4e | 1211 | edge_iterator ei; |
2ecfd709 ZD |
1212 | lbb = st[--sp]; |
1213 | if (reverse) | |
c22cacf3 | 1214 | { |
628f6a4e | 1215 | FOR_EACH_EDGE (e, ei, lbb->preds) |
9e32d2be | 1216 | if (!VISITED_P (e->src) && predicate (e->src, data)) |
2ecfd709 | 1217 | { |
c22cacf3 MS |
1218 | gcc_assert (tv != rslt_max); |
1219 | rslt[tv++] = st[sp++] = e->src; | |
1220 | MARK_VISITED (e->src); | |
2ecfd709 | 1221 | } |
c22cacf3 | 1222 | } |
2ecfd709 | 1223 | else |
c22cacf3 | 1224 | { |
628f6a4e | 1225 | FOR_EACH_EDGE (e, ei, lbb->succs) |
9e32d2be | 1226 | if (!VISITED_P (e->dest) && predicate (e->dest, data)) |
2ecfd709 | 1227 | { |
c22cacf3 MS |
1228 | gcc_assert (tv != rslt_max); |
1229 | rslt[tv++] = st[sp++] = e->dest; | |
1230 | MARK_VISITED (e->dest); | |
2ecfd709 ZD |
1231 | } |
1232 | } | |
1233 | } | |
1234 | free (st); | |
1235 | for (sp = 0; sp < tv; sp++) | |
9e32d2be | 1236 | UNMARK_VISITED (rslt[sp]); |
2ecfd709 | 1237 | return tv; |
9e32d2be ZD |
1238 | #undef MARK_VISITED |
1239 | #undef UNMARK_VISITED | |
1240 | #undef VISITED_P | |
2ecfd709 | 1241 | } |
bd454efd SB |
1242 | |
1243 | ||
4c7f5fea | 1244 | /* Compute dominance frontiers, ala Harvey, Ferrante, et al. |
c22cacf3 | 1245 | |
4c7f5fea | 1246 | This algorithm can be found in Timothy Harvey's PhD thesis, at |
708bde14 | 1247 | http://www.cs.rice.edu/~harv/dissertation.pdf in the section on iterative |
4c7f5fea | 1248 | dominance algorithms. |
bd454efd | 1249 | |
4c7f5fea | 1250 | First, we identify each join point, j (any node with more than one |
c22cacf3 | 1251 | incoming edge is a join point). |
bd454efd | 1252 | |
4c7f5fea | 1253 | We then examine each predecessor, p, of j and walk up the dominator tree |
c22cacf3 MS |
1254 | starting at p. |
1255 | ||
4c7f5fea DB |
1256 | We stop the walk when we reach j's immediate dominator - j is in the |
1257 | dominance frontier of each of the nodes in the walk, except for j's | |
1258 | immediate dominator. Intuitively, all of the rest of j's dominators are | |
1259 | shared by j's predecessors as well. | |
1260 | Since they dominate j, they will not have j in their dominance frontiers. | |
1261 | ||
c22cacf3 | 1262 | The number of nodes touched by this algorithm is equal to the size |
4c7f5fea DB |
1263 | of the dominance frontiers, no more, no less. |
1264 | */ | |
bd454efd | 1265 | |
bd454efd SB |
1266 | |
1267 | static void | |
0fc555fb | 1268 | compute_dominance_frontiers_1 (bitmap_head *frontiers) |
bd454efd | 1269 | { |
4c7f5fea | 1270 | edge p; |
628f6a4e | 1271 | edge_iterator ei; |
4c7f5fea | 1272 | basic_block b; |
11cd3bed | 1273 | FOR_EACH_BB_FN (b, cfun) |
bd454efd | 1274 | { |
4c7f5fea | 1275 | if (EDGE_COUNT (b->preds) >= 2) |
bd454efd | 1276 | { |
4c7f5fea DB |
1277 | FOR_EACH_EDGE (p, ei, b->preds) |
1278 | { | |
1279 | basic_block runner = p->src; | |
1280 | basic_block domsb; | |
fefa31b5 | 1281 | if (runner == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
4c7f5fea | 1282 | continue; |
c22cacf3 | 1283 | |
4c7f5fea DB |
1284 | domsb = get_immediate_dominator (CDI_DOMINATORS, b); |
1285 | while (runner != domsb) | |
1286 | { | |
0fc555fb | 1287 | if (!bitmap_set_bit (&frontiers[runner->index], |
f3cf730b | 1288 | b->index)) |
26eeea94 | 1289 | break; |
4c7f5fea DB |
1290 | runner = get_immediate_dominator (CDI_DOMINATORS, |
1291 | runner); | |
1292 | } | |
1293 | } | |
87c476a2 | 1294 | } |
bd454efd | 1295 | } |
c22cacf3 MS |
1296 | } |
1297 | ||
bd454efd SB |
1298 | |
1299 | void | |
0fc555fb | 1300 | compute_dominance_frontiers (bitmap_head *frontiers) |
bd454efd | 1301 | { |
bd454efd SB |
1302 | timevar_push (TV_DOM_FRONTIERS); |
1303 | ||
4c7f5fea | 1304 | compute_dominance_frontiers_1 (frontiers); |
bd454efd SB |
1305 | |
1306 | timevar_pop (TV_DOM_FRONTIERS); | |
1307 | } | |
25e87727 SB |
1308 | |
1309 | /* Given a set of blocks with variable definitions (DEF_BLOCKS), | |
1310 | return a bitmap with all the blocks in the iterated dominance | |
1311 | frontier of the blocks in DEF_BLOCKS. DFS contains dominance | |
1312 | frontier information as returned by compute_dominance_frontiers. | |
1313 | ||
1314 | The resulting set of blocks are the potential sites where PHI nodes | |
1315 | are needed. The caller is responsible for freeing the memory | |
1316 | allocated for the return value. */ | |
1317 | ||
1318 | bitmap | |
0fc555fb | 1319 | compute_idf (bitmap def_blocks, bitmap_head *dfs) |
25e87727 SB |
1320 | { |
1321 | bitmap_iterator bi; | |
1322 | unsigned bb_index, i; | |
25e87727 SB |
1323 | bitmap phi_insertion_points; |
1324 | ||
11452e7b | 1325 | /* Each block can appear at most twice on the work-stack. */ |
ef062b13 | 1326 | auto_vec<int> work_stack (2 * n_basic_blocks_for_fn (cfun)); |
25e87727 SB |
1327 | phi_insertion_points = BITMAP_ALLOC (NULL); |
1328 | ||
1329 | /* Seed the work list with all the blocks in DEF_BLOCKS. We use | |
9771b263 | 1330 | vec::quick_push here for speed. This is safe because we know that |
25e87727 SB |
1331 | the number of definition blocks is no greater than the number of |
1332 | basic blocks, which is the initial capacity of WORK_STACK. */ | |
1333 | EXECUTE_IF_SET_IN_BITMAP (def_blocks, 0, bb_index, bi) | |
9771b263 | 1334 | work_stack.quick_push (bb_index); |
25e87727 SB |
1335 | |
1336 | /* Pop a block off the worklist, add every block that appears in | |
1337 | the original block's DF that we have not already processed to | |
1338 | the worklist. Iterate until the worklist is empty. Blocks | |
1339 | which are added to the worklist are potential sites for | |
1340 | PHI nodes. */ | |
9771b263 | 1341 | while (work_stack.length () > 0) |
25e87727 | 1342 | { |
9771b263 | 1343 | bb_index = work_stack.pop (); |
25e87727 SB |
1344 | |
1345 | /* Since the registration of NEW -> OLD name mappings is done | |
1346 | separately from the call to update_ssa, when updating the SSA | |
1347 | form, the basic blocks where new and/or old names are defined | |
1348 | may have disappeared by CFG cleanup calls. In this case, | |
1349 | we may pull a non-existing block from the work stack. */ | |
8b1c6fd7 DM |
1350 | gcc_checking_assert (bb_index |
1351 | < (unsigned) last_basic_block_for_fn (cfun)); | |
25e87727 | 1352 | |
0fc555fb | 1353 | EXECUTE_IF_AND_COMPL_IN_BITMAP (&dfs[bb_index], phi_insertion_points, |
25e87727 SB |
1354 | 0, i, bi) |
1355 | { | |
11452e7b | 1356 | work_stack.quick_push (i); |
25e87727 SB |
1357 | bitmap_set_bit (phi_insertion_points, i); |
1358 | } | |
1359 | } | |
1360 | ||
25e87727 SB |
1361 | return phi_insertion_points; |
1362 | } | |
1363 | ||
3c2c4f22 SB |
1364 | /* Intersection and union of preds/succs for sbitmap based data flow |
1365 | solvers. All four functions defined below take the same arguments: | |
1366 | B is the basic block to perform the operation for. DST is the | |
1367 | target sbitmap, i.e. the result. SRC is an sbitmap vector of size | |
1368 | last_basic_block so that it can be indexed with basic block indices. | |
1369 | DST may be (but does not have to be) SRC[B->index]. */ | |
25e87727 | 1370 | |
3c2c4f22 SB |
1371 | /* Set the bitmap DST to the intersection of SRC of successors of |
1372 | basic block B. */ | |
1373 | ||
1374 | void | |
d7c028c0 | 1375 | bitmap_intersection_of_succs (sbitmap dst, sbitmap *src, basic_block b) |
3c2c4f22 SB |
1376 | { |
1377 | unsigned int set_size = dst->size; | |
1378 | edge e; | |
1379 | unsigned ix; | |
1380 | ||
1381 | gcc_assert (!dst->popcount); | |
1382 | ||
1383 | for (e = NULL, ix = 0; ix < EDGE_COUNT (b->succs); ix++) | |
1384 | { | |
1385 | e = EDGE_SUCC (b, ix); | |
fefa31b5 | 1386 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1387 | continue; |
1388 | ||
f61e445a | 1389 | bitmap_copy (dst, src[e->dest->index]); |
3c2c4f22 SB |
1390 | break; |
1391 | } | |
1392 | ||
1393 | if (e == 0) | |
f61e445a | 1394 | bitmap_ones (dst); |
3c2c4f22 SB |
1395 | else |
1396 | for (++ix; ix < EDGE_COUNT (b->succs); ix++) | |
1397 | { | |
1398 | unsigned int i; | |
1399 | SBITMAP_ELT_TYPE *p, *r; | |
1400 | ||
1401 | e = EDGE_SUCC (b, ix); | |
fefa31b5 | 1402 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1403 | continue; |
1404 | ||
1405 | p = src[e->dest->index]->elms; | |
1406 | r = dst->elms; | |
1407 | for (i = 0; i < set_size; i++) | |
1408 | *r++ &= *p++; | |
1409 | } | |
1410 | } | |
1411 | ||
1412 | /* Set the bitmap DST to the intersection of SRC of predecessors of | |
1413 | basic block B. */ | |
1414 | ||
1415 | void | |
d7c028c0 | 1416 | bitmap_intersection_of_preds (sbitmap dst, sbitmap *src, basic_block b) |
3c2c4f22 SB |
1417 | { |
1418 | unsigned int set_size = dst->size; | |
1419 | edge e; | |
1420 | unsigned ix; | |
1421 | ||
1422 | gcc_assert (!dst->popcount); | |
1423 | ||
1424 | for (e = NULL, ix = 0; ix < EDGE_COUNT (b->preds); ix++) | |
1425 | { | |
1426 | e = EDGE_PRED (b, ix); | |
fefa31b5 | 1427 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1428 | continue; |
1429 | ||
f61e445a | 1430 | bitmap_copy (dst, src[e->src->index]); |
3c2c4f22 SB |
1431 | break; |
1432 | } | |
1433 | ||
1434 | if (e == 0) | |
f61e445a | 1435 | bitmap_ones (dst); |
3c2c4f22 SB |
1436 | else |
1437 | for (++ix; ix < EDGE_COUNT (b->preds); ix++) | |
1438 | { | |
1439 | unsigned int i; | |
1440 | SBITMAP_ELT_TYPE *p, *r; | |
1441 | ||
1442 | e = EDGE_PRED (b, ix); | |
fefa31b5 | 1443 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1444 | continue; |
1445 | ||
1446 | p = src[e->src->index]->elms; | |
1447 | r = dst->elms; | |
1448 | for (i = 0; i < set_size; i++) | |
1449 | *r++ &= *p++; | |
1450 | } | |
1451 | } | |
1452 | ||
1453 | /* Set the bitmap DST to the union of SRC of successors of | |
1454 | basic block B. */ | |
1455 | ||
1456 | void | |
d7c028c0 | 1457 | bitmap_union_of_succs (sbitmap dst, sbitmap *src, basic_block b) |
3c2c4f22 SB |
1458 | { |
1459 | unsigned int set_size = dst->size; | |
1460 | edge e; | |
1461 | unsigned ix; | |
1462 | ||
1463 | gcc_assert (!dst->popcount); | |
1464 | ||
1465 | for (ix = 0; ix < EDGE_COUNT (b->succs); ix++) | |
1466 | { | |
1467 | e = EDGE_SUCC (b, ix); | |
fefa31b5 | 1468 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1469 | continue; |
1470 | ||
f61e445a | 1471 | bitmap_copy (dst, src[e->dest->index]); |
3c2c4f22 SB |
1472 | break; |
1473 | } | |
1474 | ||
1475 | if (ix == EDGE_COUNT (b->succs)) | |
f61e445a | 1476 | bitmap_clear (dst); |
3c2c4f22 SB |
1477 | else |
1478 | for (ix++; ix < EDGE_COUNT (b->succs); ix++) | |
1479 | { | |
1480 | unsigned int i; | |
1481 | SBITMAP_ELT_TYPE *p, *r; | |
1482 | ||
1483 | e = EDGE_SUCC (b, ix); | |
fefa31b5 | 1484 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1485 | continue; |
1486 | ||
1487 | p = src[e->dest->index]->elms; | |
1488 | r = dst->elms; | |
1489 | for (i = 0; i < set_size; i++) | |
1490 | *r++ |= *p++; | |
1491 | } | |
1492 | } | |
1493 | ||
1494 | /* Set the bitmap DST to the union of SRC of predecessors of | |
1495 | basic block B. */ | |
1496 | ||
1497 | void | |
d7c028c0 | 1498 | bitmap_union_of_preds (sbitmap dst, sbitmap *src, basic_block b) |
3c2c4f22 SB |
1499 | { |
1500 | unsigned int set_size = dst->size; | |
1501 | edge e; | |
1502 | unsigned ix; | |
1503 | ||
1504 | gcc_assert (!dst->popcount); | |
1505 | ||
1506 | for (ix = 0; ix < EDGE_COUNT (b->preds); ix++) | |
1507 | { | |
1508 | e = EDGE_PRED (b, ix); | |
fefa31b5 | 1509 | if (e->src== ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1510 | continue; |
1511 | ||
f61e445a | 1512 | bitmap_copy (dst, src[e->src->index]); |
3c2c4f22 SB |
1513 | break; |
1514 | } | |
1515 | ||
1516 | if (ix == EDGE_COUNT (b->preds)) | |
f61e445a | 1517 | bitmap_clear (dst); |
3c2c4f22 SB |
1518 | else |
1519 | for (ix++; ix < EDGE_COUNT (b->preds); ix++) | |
1520 | { | |
1521 | unsigned int i; | |
1522 | SBITMAP_ELT_TYPE *p, *r; | |
1523 | ||
1524 | e = EDGE_PRED (b, ix); | |
fefa31b5 | 1525 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1526 | continue; |
1527 | ||
1528 | p = src[e->src->index]->elms; | |
1529 | r = dst->elms; | |
1530 | for (i = 0; i < set_size; i++) | |
1531 | *r++ |= *p++; | |
1532 | } | |
1533 | } | |
3d9c733e AM |
1534 | |
1535 | /* Returns the list of basic blocks in the function in an order that guarantees | |
1536 | that if a block X has just a single predecessor Y, then Y is after X in the | |
1537 | ordering. */ | |
1538 | ||
1539 | basic_block * | |
1540 | single_pred_before_succ_order (void) | |
1541 | { | |
1542 | basic_block x, y; | |
0cae8d31 DM |
1543 | basic_block *order = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun)); |
1544 | unsigned n = n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; | |
3d9c733e | 1545 | unsigned np, i; |
8b1c6fd7 | 1546 | sbitmap visited = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
3d9c733e AM |
1547 | |
1548 | #define MARK_VISITED(BB) (bitmap_set_bit (visited, (BB)->index)) | |
1549 | #define VISITED_P(BB) (bitmap_bit_p (visited, (BB)->index)) | |
1550 | ||
1551 | bitmap_clear (visited); | |
1552 | ||
fefa31b5 | 1553 | MARK_VISITED (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
11cd3bed | 1554 | FOR_EACH_BB_FN (x, cfun) |
3d9c733e AM |
1555 | { |
1556 | if (VISITED_P (x)) | |
1557 | continue; | |
1558 | ||
1559 | /* Walk the predecessors of x as long as they have precisely one | |
1560 | predecessor and add them to the list, so that they get stored | |
1561 | after x. */ | |
1562 | for (y = x, np = 1; | |
1563 | single_pred_p (y) && !VISITED_P (single_pred (y)); | |
1564 | y = single_pred (y)) | |
1565 | np++; | |
1566 | for (y = x, i = n - np; | |
1567 | single_pred_p (y) && !VISITED_P (single_pred (y)); | |
1568 | y = single_pred (y), i++) | |
1569 | { | |
1570 | order[i] = y; | |
1571 | MARK_VISITED (y); | |
1572 | } | |
1573 | order[i] = y; | |
1574 | MARK_VISITED (y); | |
1575 | ||
1576 | gcc_assert (i == n - 1); | |
1577 | n -= np; | |
1578 | } | |
1579 | ||
1580 | sbitmap_free (visited); | |
1581 | gcc_assert (n == 0); | |
1582 | return order; | |
1583 | ||
1584 | #undef MARK_VISITED | |
1585 | #undef VISITED_P | |
1586 | } |