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402209ff | 1 | /* Control flow graph analysis code for GNU compiler. |
8d9254fc | 2 | Copyright (C) 1987-2020 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" |
44ab146a | 29 | #include "cfgloop.h" |
402209ff | 30 | |
35bfaf4d | 31 | namespace { |
402209ff | 32 | /* Store the data structures necessary for depth-first search. */ |
35bfaf4d TS |
33 | class depth_first_search |
34 | { | |
35 | public: | |
36 | depth_first_search (); | |
37 | ||
38 | basic_block execute (basic_block); | |
39 | void add_bb (basic_block); | |
402209ff | 40 | |
35bfaf4d TS |
41 | private: |
42 | /* stack for backtracking during the algorithm */ | |
43 | auto_vec<basic_block, 20> m_stack; | |
402209ff JH |
44 | |
45 | /* record of basic blocks already seen by depth-first search */ | |
35bfaf4d | 46 | auto_sbitmap m_visited_blocks; |
402209ff | 47 | }; |
35bfaf4d | 48 | } |
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 | { |
402209ff JH |
63 | int *pre; |
64 | int *post; | |
402209ff JH |
65 | int prenum = 1; |
66 | int postnum = 1; | |
402209ff JH |
67 | bool found = false; |
68 | ||
69 | /* Allocate the preorder and postorder number arrays. */ | |
8b1c6fd7 DM |
70 | pre = XCNEWVEC (int, last_basic_block_for_fn (cfun)); |
71 | post = XCNEWVEC (int, last_basic_block_for_fn (cfun)); | |
402209ff JH |
72 | |
73 | /* Allocate stack for back-tracking up CFG. */ | |
792bb49b | 74 | auto_vec<edge_iterator, 20> stack (n_basic_blocks_for_fn (cfun) + 1); |
402209ff JH |
75 | |
76 | /* Allocate bitmap to track nodes that have been visited. */ | |
7ba9e72d | 77 | auto_sbitmap visited (last_basic_block_for_fn (cfun)); |
402209ff JH |
78 | |
79 | /* None of the nodes in the CFG have been visited yet. */ | |
f61e445a | 80 | bitmap_clear (visited); |
402209ff JH |
81 | |
82 | /* Push the first edge on to the stack. */ | |
792bb49b | 83 | stack.quick_push (ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs)); |
402209ff | 84 | |
792bb49b | 85 | while (!stack.is_empty ()) |
402209ff | 86 | { |
402209ff JH |
87 | basic_block src; |
88 | basic_block dest; | |
89 | ||
90 | /* Look at the edge on the top of the stack. */ | |
792bb49b | 91 | edge_iterator ei = stack.last (); |
628f6a4e BE |
92 | src = ei_edge (ei)->src; |
93 | dest = ei_edge (ei)->dest; | |
94 | ei_edge (ei)->flags &= ~EDGE_DFS_BACK; | |
402209ff JH |
95 | |
96 | /* Check if the edge destination has been visited yet. */ | |
fefa31b5 DM |
97 | if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun) && ! bitmap_bit_p (visited, |
98 | dest->index)) | |
402209ff JH |
99 | { |
100 | /* Mark that we have visited the destination. */ | |
d7c028c0 | 101 | bitmap_set_bit (visited, dest->index); |
402209ff | 102 | |
0b17ab2f | 103 | pre[dest->index] = prenum++; |
628f6a4e | 104 | if (EDGE_COUNT (dest->succs) > 0) |
402209ff JH |
105 | { |
106 | /* Since the DEST node has been visited for the first | |
107 | time, check its successors. */ | |
792bb49b | 108 | stack.quick_push (ei_start (dest->succs)); |
402209ff JH |
109 | } |
110 | else | |
0b17ab2f | 111 | post[dest->index] = postnum++; |
402209ff JH |
112 | } |
113 | else | |
114 | { | |
fefa31b5 DM |
115 | if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun) |
116 | && src != ENTRY_BLOCK_PTR_FOR_FN (cfun) | |
0b17ab2f RH |
117 | && pre[src->index] >= pre[dest->index] |
118 | && post[dest->index] == 0) | |
628f6a4e | 119 | ei_edge (ei)->flags |= EDGE_DFS_BACK, found = true; |
402209ff | 120 | |
fefa31b5 DM |
121 | if (ei_one_before_end_p (ei) |
122 | && src != ENTRY_BLOCK_PTR_FOR_FN (cfun)) | |
0b17ab2f | 123 | post[src->index] = postnum++; |
402209ff | 124 | |
628f6a4e | 125 | if (!ei_one_before_end_p (ei)) |
792bb49b | 126 | ei_next (&stack.last ()); |
402209ff | 127 | else |
792bb49b | 128 | stack.pop (); |
402209ff JH |
129 | } |
130 | } | |
131 | ||
132 | free (pre); | |
133 | free (post); | |
402209ff JH |
134 | |
135 | return found; | |
136 | } | |
137 | ||
402209ff | 138 | /* Find unreachable blocks. An unreachable block will have 0 in |
da7d8304 | 139 | the reachable bit in block->flags. A nonzero value indicates the |
402209ff JH |
140 | block is reachable. */ |
141 | ||
142 | void | |
d329e058 | 143 | find_unreachable_blocks (void) |
402209ff JH |
144 | { |
145 | edge e; | |
628f6a4e | 146 | edge_iterator ei; |
e0082a72 | 147 | basic_block *tos, *worklist, bb; |
402209ff | 148 | |
0cae8d31 | 149 | tos = worklist = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun)); |
402209ff JH |
150 | |
151 | /* Clear all the reachability flags. */ | |
152 | ||
11cd3bed | 153 | FOR_EACH_BB_FN (bb, cfun) |
e0082a72 | 154 | bb->flags &= ~BB_REACHABLE; |
402209ff JH |
155 | |
156 | /* Add our starting points to the worklist. Almost always there will | |
eaec9b3d | 157 | be only one. It isn't inconceivable that we might one day directly |
402209ff JH |
158 | support Fortran alternate entry points. */ |
159 | ||
fefa31b5 | 160 | FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs) |
402209ff JH |
161 | { |
162 | *tos++ = e->dest; | |
163 | ||
164 | /* Mark the block reachable. */ | |
165 | e->dest->flags |= BB_REACHABLE; | |
166 | } | |
167 | ||
168 | /* Iterate: find everything reachable from what we've already seen. */ | |
169 | ||
170 | while (tos != worklist) | |
171 | { | |
172 | basic_block b = *--tos; | |
173 | ||
628f6a4e | 174 | FOR_EACH_EDGE (e, ei, b->succs) |
0b612e0b JL |
175 | { |
176 | basic_block dest = e->dest; | |
177 | ||
178 | if (!(dest->flags & BB_REACHABLE)) | |
179 | { | |
180 | *tos++ = dest; | |
181 | dest->flags |= BB_REACHABLE; | |
182 | } | |
183 | } | |
402209ff JH |
184 | } |
185 | ||
186 | free (worklist); | |
187 | } | |
a352b710 TV |
188 | |
189 | /* Verify that there are no unreachable blocks in the current function. */ | |
190 | ||
191 | void | |
192 | verify_no_unreachable_blocks (void) | |
193 | { | |
194 | find_unreachable_blocks (); | |
195 | ||
196 | basic_block bb; | |
197 | FOR_EACH_BB_FN (bb, cfun) | |
198 | gcc_assert ((bb->flags & BB_REACHABLE) != 0); | |
199 | } | |
200 | ||
402209ff JH |
201 | \f |
202 | /* Functions to access an edge list with a vector representation. | |
203 | Enough data is kept such that given an index number, the | |
204 | pred and succ that edge represents can be determined, or | |
205 | given a pred and a succ, its index number can be returned. | |
206 | This allows algorithms which consume a lot of memory to | |
207 | represent the normally full matrix of edge (pred,succ) with a | |
208 | single indexed vector, edge (EDGE_INDEX (pred, succ)), with no | |
209 | wasted space in the client code due to sparse flow graphs. */ | |
210 | ||
211 | /* This functions initializes the edge list. Basically the entire | |
212 | flowgraph is processed, and all edges are assigned a number, | |
213 | and the data structure is filled in. */ | |
214 | ||
215 | struct edge_list * | |
d329e058 | 216 | create_edge_list (void) |
402209ff JH |
217 | { |
218 | struct edge_list *elist; | |
219 | edge e; | |
220 | int num_edges; | |
e0082a72 | 221 | basic_block bb; |
628f6a4e | 222 | edge_iterator ei; |
402209ff | 223 | |
402209ff JH |
224 | /* Determine the number of edges in the flow graph by counting successor |
225 | edges on each basic block. */ | |
532aafad | 226 | num_edges = 0; |
fefa31b5 DM |
227 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
228 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
402209ff | 229 | { |
628f6a4e | 230 | num_edges += EDGE_COUNT (bb->succs); |
402209ff | 231 | } |
4891442b | 232 | |
5ed6ace5 | 233 | elist = XNEW (struct edge_list); |
402209ff | 234 | elist->num_edges = num_edges; |
5ed6ace5 | 235 | elist->index_to_edge = XNEWVEC (edge, num_edges); |
402209ff JH |
236 | |
237 | num_edges = 0; | |
238 | ||
e0082a72 | 239 | /* Follow successors of blocks, and register these edges. */ |
fefa31b5 DM |
240 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
241 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
628f6a4e | 242 | FOR_EACH_EDGE (e, ei, bb->succs) |
e0082a72 | 243 | elist->index_to_edge[num_edges++] = e; |
4891442b | 244 | |
402209ff JH |
245 | return elist; |
246 | } | |
247 | ||
248 | /* This function free's memory associated with an edge list. */ | |
249 | ||
250 | void | |
d329e058 | 251 | free_edge_list (struct edge_list *elist) |
402209ff JH |
252 | { |
253 | if (elist) | |
254 | { | |
255 | free (elist->index_to_edge); | |
256 | free (elist); | |
257 | } | |
258 | } | |
259 | ||
260 | /* This function provides debug output showing an edge list. */ | |
261 | ||
24e47c76 | 262 | DEBUG_FUNCTION void |
d329e058 | 263 | print_edge_list (FILE *f, struct edge_list *elist) |
402209ff JH |
264 | { |
265 | int x; | |
4891442b | 266 | |
402209ff | 267 | fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n", |
0cae8d31 | 268 | n_basic_blocks_for_fn (cfun), elist->num_edges); |
402209ff JH |
269 | |
270 | for (x = 0; x < elist->num_edges; x++) | |
271 | { | |
272 | fprintf (f, " %-4d - edge(", x); | |
fefa31b5 | 273 | if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
402209ff JH |
274 | fprintf (f, "entry,"); |
275 | else | |
0b17ab2f | 276 | fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index); |
402209ff | 277 | |
fefa31b5 | 278 | if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
402209ff JH |
279 | fprintf (f, "exit)\n"); |
280 | else | |
0b17ab2f | 281 | fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index); |
402209ff JH |
282 | } |
283 | } | |
284 | ||
285 | /* This function provides an internal consistency check of an edge list, | |
286 | verifying that all edges are present, and that there are no | |
287 | extra edges. */ | |
288 | ||
24e47c76 | 289 | DEBUG_FUNCTION void |
d329e058 | 290 | verify_edge_list (FILE *f, struct edge_list *elist) |
402209ff | 291 | { |
e0082a72 | 292 | int pred, succ, index; |
402209ff | 293 | edge e; |
e0082a72 | 294 | basic_block bb, p, s; |
628f6a4e | 295 | edge_iterator ei; |
402209ff | 296 | |
fefa31b5 DM |
297 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
298 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
402209ff | 299 | { |
628f6a4e | 300 | FOR_EACH_EDGE (e, ei, bb->succs) |
402209ff | 301 | { |
0b17ab2f RH |
302 | pred = e->src->index; |
303 | succ = e->dest->index; | |
402209ff JH |
304 | index = EDGE_INDEX (elist, e->src, e->dest); |
305 | if (index == EDGE_INDEX_NO_EDGE) | |
306 | { | |
307 | fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ); | |
308 | continue; | |
309 | } | |
4891442b | 310 | |
0b17ab2f | 311 | if (INDEX_EDGE_PRED_BB (elist, index)->index != pred) |
402209ff | 312 | fprintf (f, "*p* Pred for index %d should be %d not %d\n", |
0b17ab2f RH |
313 | index, pred, INDEX_EDGE_PRED_BB (elist, index)->index); |
314 | if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ) | |
402209ff | 315 | fprintf (f, "*p* Succ for index %d should be %d not %d\n", |
0b17ab2f RH |
316 | index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index); |
317 | } | |
318 | } | |
319 | ||
e0082a72 | 320 | /* We've verified that all the edges are in the list, now lets make sure |
532aafad | 321 | there are no spurious edges in the list. This is an expensive check! */ |
402209ff | 322 | |
fefa31b5 DM |
323 | FOR_BB_BETWEEN (p, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
324 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
325 | FOR_BB_BETWEEN (s, ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb, NULL, next_bb) | |
402209ff | 326 | { |
402209ff JH |
327 | int found_edge = 0; |
328 | ||
628f6a4e | 329 | FOR_EACH_EDGE (e, ei, p->succs) |
402209ff JH |
330 | if (e->dest == s) |
331 | { | |
332 | found_edge = 1; | |
333 | break; | |
334 | } | |
4891442b | 335 | |
628f6a4e | 336 | FOR_EACH_EDGE (e, ei, s->preds) |
402209ff JH |
337 | if (e->src == p) |
338 | { | |
339 | found_edge = 1; | |
340 | break; | |
341 | } | |
4891442b | 342 | |
e0082a72 | 343 | if (EDGE_INDEX (elist, p, s) |
402209ff JH |
344 | == EDGE_INDEX_NO_EDGE && found_edge != 0) |
345 | fprintf (f, "*** Edge (%d, %d) appears to not have an index\n", | |
e0082a72 ZD |
346 | p->index, s->index); |
347 | if (EDGE_INDEX (elist, p, s) | |
402209ff JH |
348 | != EDGE_INDEX_NO_EDGE && found_edge == 0) |
349 | fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n", | |
e0082a72 | 350 | p->index, s->index, EDGE_INDEX (elist, p, s)); |
402209ff | 351 | } |
402209ff JH |
352 | } |
353 | ||
c8e9d8c3 RB |
354 | |
355 | /* Functions to compute control dependences. */ | |
356 | ||
357 | /* Indicate block BB is control dependent on an edge with index EDGE_INDEX. */ | |
358 | void | |
359 | control_dependences::set_control_dependence_map_bit (basic_block bb, | |
360 | int edge_index) | |
361 | { | |
fefa31b5 | 362 | if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
c8e9d8c3 | 363 | return; |
fefa31b5 | 364 | gcc_assert (bb != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
c8e9d8c3 RB |
365 | bitmap_set_bit (control_dependence_map[bb->index], edge_index); |
366 | } | |
367 | ||
368 | /* Clear all control dependences for block BB. */ | |
369 | void | |
370 | control_dependences::clear_control_dependence_bitmap (basic_block bb) | |
371 | { | |
372 | bitmap_clear (control_dependence_map[bb->index]); | |
373 | } | |
374 | ||
375 | /* Find the immediate postdominator PDOM of the specified basic block BLOCK. | |
376 | This function is necessary because some blocks have negative numbers. */ | |
377 | ||
378 | static inline basic_block | |
379 | find_pdom (basic_block block) | |
380 | { | |
fefa31b5 | 381 | gcc_assert (block != ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
c8e9d8c3 | 382 | |
fefa31b5 DM |
383 | if (block == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
384 | return EXIT_BLOCK_PTR_FOR_FN (cfun); | |
c8e9d8c3 RB |
385 | else |
386 | { | |
387 | basic_block bb = get_immediate_dominator (CDI_POST_DOMINATORS, block); | |
388 | if (! bb) | |
fefa31b5 | 389 | return EXIT_BLOCK_PTR_FOR_FN (cfun); |
c8e9d8c3 RB |
390 | return bb; |
391 | } | |
392 | } | |
393 | ||
394 | /* Determine all blocks' control dependences on the given edge with edge_list | |
395 | EL index EDGE_INDEX, ala Morgan, Section 3.6. */ | |
396 | ||
397 | void | |
398 | control_dependences::find_control_dependence (int edge_index) | |
399 | { | |
400 | basic_block current_block; | |
401 | basic_block ending_block; | |
402 | ||
30fd2977 | 403 | gcc_assert (get_edge_src (edge_index) != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
c8e9d8c3 | 404 | |
30fd2977 RB |
405 | /* For abnormal edges, we don't make current_block control |
406 | dependent because instructions that throw are always necessary | |
407 | anyway. */ | |
408 | edge e = find_edge (get_edge_src (edge_index), get_edge_dest (edge_index)); | |
409 | if (e->flags & EDGE_ABNORMAL) | |
410 | return; | |
411 | ||
412 | if (get_edge_src (edge_index) == ENTRY_BLOCK_PTR_FOR_FN (cfun)) | |
fefa31b5 | 413 | ending_block = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
c8e9d8c3 | 414 | else |
30fd2977 | 415 | ending_block = find_pdom (get_edge_src (edge_index)); |
c8e9d8c3 | 416 | |
30fd2977 | 417 | for (current_block = get_edge_dest (edge_index); |
fefa31b5 DM |
418 | current_block != ending_block |
419 | && current_block != EXIT_BLOCK_PTR_FOR_FN (cfun); | |
c8e9d8c3 | 420 | current_block = find_pdom (current_block)) |
30fd2977 | 421 | set_control_dependence_map_bit (current_block, edge_index); |
c8e9d8c3 RB |
422 | } |
423 | ||
424 | /* Record all blocks' control dependences on all edges in the edge | |
425 | list EL, ala Morgan, Section 3.6. */ | |
426 | ||
30fd2977 | 427 | control_dependences::control_dependences () |
c8e9d8c3 RB |
428 | { |
429 | timevar_push (TV_CONTROL_DEPENDENCES); | |
30fd2977 RB |
430 | |
431 | /* Initialize the edge list. */ | |
432 | int num_edges = 0; | |
433 | basic_block bb; | |
434 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), | |
435 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
436 | num_edges += EDGE_COUNT (bb->succs); | |
437 | m_el.create (num_edges); | |
438 | edge e; | |
439 | edge_iterator ei; | |
440 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), | |
441 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
442 | FOR_EACH_EDGE (e, ei, bb->succs) | |
443 | m_el.quick_push (std::make_pair (e->src->index, e->dest->index)); | |
444 | ||
8b1c6fd7 DM |
445 | control_dependence_map.create (last_basic_block_for_fn (cfun)); |
446 | for (int i = 0; i < last_basic_block_for_fn (cfun); ++i) | |
c8e9d8c3 | 447 | control_dependence_map.quick_push (BITMAP_ALLOC (NULL)); |
30fd2977 | 448 | for (int i = 0; i < num_edges; ++i) |
c8e9d8c3 | 449 | find_control_dependence (i); |
30fd2977 | 450 | |
c8e9d8c3 RB |
451 | timevar_pop (TV_CONTROL_DEPENDENCES); |
452 | } | |
453 | ||
454 | /* Free control dependences and the associated edge list. */ | |
455 | ||
456 | control_dependences::~control_dependences () | |
457 | { | |
f23c0742 | 458 | for (unsigned i = 0; i < control_dependence_map.length (); ++i) |
c8e9d8c3 RB |
459 | BITMAP_FREE (control_dependence_map[i]); |
460 | control_dependence_map.release (); | |
30fd2977 | 461 | m_el.release (); |
c8e9d8c3 RB |
462 | } |
463 | ||
464 | /* Returns the bitmap of edges the basic-block I is dependent on. */ | |
465 | ||
466 | bitmap | |
467 | control_dependences::get_edges_dependent_on (int i) | |
468 | { | |
469 | return control_dependence_map[i]; | |
470 | } | |
471 | ||
30fd2977 | 472 | /* Returns the edge source with index I from the edge list. */ |
c8e9d8c3 | 473 | |
30fd2977 RB |
474 | basic_block |
475 | control_dependences::get_edge_src (int i) | |
476 | { | |
477 | return BASIC_BLOCK_FOR_FN (cfun, m_el[i].first); | |
478 | } | |
479 | ||
480 | /* Returns the edge destination with index I from the edge list. */ | |
481 | ||
482 | basic_block | |
483 | control_dependences::get_edge_dest (int i) | |
c8e9d8c3 | 484 | { |
30fd2977 | 485 | return BASIC_BLOCK_FOR_FN (cfun, m_el[i].second); |
c8e9d8c3 RB |
486 | } |
487 | ||
488 | ||
6de9cd9a DN |
489 | /* Given PRED and SUCC blocks, return the edge which connects the blocks. |
490 | If no such edge exists, return NULL. */ | |
491 | ||
492 | edge | |
493 | find_edge (basic_block pred, basic_block succ) | |
494 | { | |
495 | edge e; | |
628f6a4e | 496 | edge_iterator ei; |
6de9cd9a | 497 | |
df95526b JL |
498 | if (EDGE_COUNT (pred->succs) <= EDGE_COUNT (succ->preds)) |
499 | { | |
500 | FOR_EACH_EDGE (e, ei, pred->succs) | |
501 | if (e->dest == succ) | |
502 | return e; | |
503 | } | |
504 | else | |
505 | { | |
506 | FOR_EACH_EDGE (e, ei, succ->preds) | |
507 | if (e->src == pred) | |
508 | return e; | |
509 | } | |
6de9cd9a DN |
510 | |
511 | return NULL; | |
512 | } | |
513 | ||
402209ff JH |
514 | /* This routine will determine what, if any, edge there is between |
515 | a specified predecessor and successor. */ | |
516 | ||
517 | int | |
d329e058 | 518 | find_edge_index (struct edge_list *edge_list, basic_block pred, basic_block succ) |
402209ff JH |
519 | { |
520 | int x; | |
4891442b | 521 | |
402209ff | 522 | for (x = 0; x < NUM_EDGES (edge_list); x++) |
4891442b RK |
523 | if (INDEX_EDGE_PRED_BB (edge_list, x) == pred |
524 | && INDEX_EDGE_SUCC_BB (edge_list, x) == succ) | |
525 | return x; | |
526 | ||
402209ff JH |
527 | return (EDGE_INDEX_NO_EDGE); |
528 | } | |
402209ff | 529 | \f |
6809cbf9 RH |
530 | /* This routine will remove any fake predecessor edges for a basic block. |
531 | When the edge is removed, it is also removed from whatever successor | |
402209ff JH |
532 | list it is in. */ |
533 | ||
534 | static void | |
6809cbf9 | 535 | remove_fake_predecessors (basic_block bb) |
402209ff JH |
536 | { |
537 | edge e; | |
628f6a4e | 538 | edge_iterator ei; |
4891442b | 539 | |
628f6a4e | 540 | for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) |
402209ff | 541 | { |
628f6a4e BE |
542 | if ((e->flags & EDGE_FAKE) == EDGE_FAKE) |
543 | remove_edge (e); | |
544 | else | |
545 | ei_next (&ei); | |
402209ff JH |
546 | } |
547 | } | |
548 | ||
549 | /* This routine will remove all fake edges from the flow graph. If | |
550 | we remove all fake successors, it will automatically remove all | |
551 | fake predecessors. */ | |
552 | ||
553 | void | |
d329e058 | 554 | remove_fake_edges (void) |
402209ff | 555 | { |
e0082a72 | 556 | basic_block bb; |
402209ff | 557 | |
fefa31b5 | 558 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb, NULL, next_bb) |
6809cbf9 | 559 | remove_fake_predecessors (bb); |
402209ff JH |
560 | } |
561 | ||
6809cbf9 RH |
562 | /* This routine will remove all fake edges to the EXIT_BLOCK. */ |
563 | ||
564 | void | |
565 | remove_fake_exit_edges (void) | |
566 | { | |
fefa31b5 | 567 | remove_fake_predecessors (EXIT_BLOCK_PTR_FOR_FN (cfun)); |
6809cbf9 RH |
568 | } |
569 | ||
570 | ||
402209ff JH |
571 | /* This function will add a fake edge between any block which has no |
572 | successors, and the exit block. Some data flow equations require these | |
573 | edges to exist. */ | |
574 | ||
575 | void | |
d329e058 | 576 | add_noreturn_fake_exit_edges (void) |
402209ff | 577 | { |
e0082a72 | 578 | basic_block bb; |
402209ff | 579 | |
11cd3bed | 580 | FOR_EACH_BB_FN (bb, cfun) |
628f6a4e | 581 | if (EDGE_COUNT (bb->succs) == 0) |
fefa31b5 | 582 | make_single_succ_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun), EDGE_FAKE); |
402209ff JH |
583 | } |
584 | ||
585 | /* This function adds a fake edge between any infinite loops to the | |
586 | exit block. Some optimizations require a path from each node to | |
587 | the exit node. | |
588 | ||
589 | See also Morgan, Figure 3.10, pp. 82-83. | |
590 | ||
591 | The current implementation is ugly, not attempting to minimize the | |
592 | number of inserted fake edges. To reduce the number of fake edges | |
593 | to insert, add fake edges from _innermost_ loops containing only | |
594 | nodes not reachable from the exit block. */ | |
595 | ||
596 | void | |
d329e058 | 597 | connect_infinite_loops_to_exit (void) |
402209ff | 598 | { |
402209ff JH |
599 | /* Perform depth-first search in the reverse graph to find nodes |
600 | reachable from the exit block. */ | |
35bfaf4d TS |
601 | depth_first_search dfs; |
602 | dfs.add_bb (EXIT_BLOCK_PTR_FOR_FN (cfun)); | |
402209ff JH |
603 | |
604 | /* Repeatedly add fake edges, updating the unreachable nodes. */ | |
35bfaf4d | 605 | basic_block unvisited_block = EXIT_BLOCK_PTR_FOR_FN (cfun); |
402209ff JH |
606 | while (1) |
607 | { | |
35bfaf4d | 608 | unvisited_block = dfs.execute (unvisited_block); |
402209ff JH |
609 | if (!unvisited_block) |
610 | break; | |
4891442b | 611 | |
35bfaf4d | 612 | basic_block deadend_block = dfs_find_deadend (unvisited_block); |
357067f2 JH |
613 | edge e = make_edge (deadend_block, EXIT_BLOCK_PTR_FOR_FN (cfun), |
614 | EDGE_FAKE); | |
357067f2 | 615 | e->probability = profile_probability::never (); |
35bfaf4d | 616 | dfs.add_bb (deadend_block); |
402209ff | 617 | } |
402209ff JH |
618 | } |
619 | \f | |
6fb5fa3c | 620 | /* Compute reverse top sort order. This is computing a post order |
dd5a833e | 621 | numbering of the graph. If INCLUDE_ENTRY_EXIT is true, then |
6fb5fa3c DB |
622 | ENTRY_BLOCK and EXIT_BLOCK are included. If DELETE_UNREACHABLE is |
623 | true, unreachable blocks are deleted. */ | |
4891442b | 624 | |
f91a0beb | 625 | int |
b8698a0f | 626 | post_order_compute (int *post_order, bool include_entry_exit, |
6fb5fa3c | 627 | bool delete_unreachable) |
402209ff | 628 | { |
f91a0beb | 629 | int post_order_num = 0; |
6fb5fa3c | 630 | int count; |
402209ff | 631 | |
f91a0beb KZ |
632 | if (include_entry_exit) |
633 | post_order[post_order_num++] = EXIT_BLOCK; | |
634 | ||
402209ff | 635 | /* Allocate stack for back-tracking up CFG. */ |
792bb49b | 636 | auto_vec<edge_iterator, 20> stack (n_basic_blocks_for_fn (cfun) + 1); |
402209ff JH |
637 | |
638 | /* Allocate bitmap to track nodes that have been visited. */ | |
7ba9e72d | 639 | auto_sbitmap visited (last_basic_block_for_fn (cfun)); |
402209ff JH |
640 | |
641 | /* None of the nodes in the CFG have been visited yet. */ | |
f61e445a | 642 | bitmap_clear (visited); |
402209ff JH |
643 | |
644 | /* Push the first edge on to the stack. */ | |
792bb49b | 645 | stack.quick_push (ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs)); |
402209ff | 646 | |
792bb49b | 647 | while (!stack.is_empty ()) |
402209ff | 648 | { |
402209ff JH |
649 | basic_block src; |
650 | basic_block dest; | |
651 | ||
652 | /* Look at the edge on the top of the stack. */ | |
792bb49b | 653 | edge_iterator ei = stack.last (); |
628f6a4e BE |
654 | src = ei_edge (ei)->src; |
655 | dest = ei_edge (ei)->dest; | |
402209ff JH |
656 | |
657 | /* Check if the edge destination has been visited yet. */ | |
fefa31b5 DM |
658 | if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun) |
659 | && ! bitmap_bit_p (visited, dest->index)) | |
402209ff JH |
660 | { |
661 | /* Mark that we have visited the destination. */ | |
d7c028c0 | 662 | bitmap_set_bit (visited, dest->index); |
402209ff | 663 | |
628f6a4e | 664 | if (EDGE_COUNT (dest->succs) > 0) |
4891442b RK |
665 | /* Since the DEST node has been visited for the first |
666 | time, check its successors. */ | |
792bb49b | 667 | stack.quick_push (ei_start (dest->succs)); |
402209ff | 668 | else |
f91a0beb | 669 | post_order[post_order_num++] = dest->index; |
402209ff JH |
670 | } |
671 | else | |
672 | { | |
fefa31b5 DM |
673 | if (ei_one_before_end_p (ei) |
674 | && src != ENTRY_BLOCK_PTR_FOR_FN (cfun)) | |
6fb5fa3c | 675 | post_order[post_order_num++] = src->index; |
402209ff | 676 | |
628f6a4e | 677 | if (!ei_one_before_end_p (ei)) |
792bb49b | 678 | ei_next (&stack.last ()); |
402209ff | 679 | else |
792bb49b | 680 | stack.pop (); |
402209ff JH |
681 | } |
682 | } | |
683 | ||
f91a0beb | 684 | if (include_entry_exit) |
6fb5fa3c DB |
685 | { |
686 | post_order[post_order_num++] = ENTRY_BLOCK; | |
687 | count = post_order_num; | |
688 | } | |
b8698a0f | 689 | else |
6fb5fa3c | 690 | count = post_order_num + 2; |
b8698a0f | 691 | |
6fb5fa3c DB |
692 | /* Delete the unreachable blocks if some were found and we are |
693 | supposed to do it. */ | |
0cae8d31 | 694 | if (delete_unreachable && (count != n_basic_blocks_for_fn (cfun))) |
6fb5fa3c DB |
695 | { |
696 | basic_block b; | |
697 | basic_block next_bb; | |
fefa31b5 DM |
698 | for (b = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; b |
699 | != EXIT_BLOCK_PTR_FOR_FN (cfun); b = next_bb) | |
6fb5fa3c DB |
700 | { |
701 | next_bb = b->next_bb; | |
b8698a0f | 702 | |
d7c028c0 | 703 | if (!(bitmap_bit_p (visited, b->index))) |
6fb5fa3c DB |
704 | delete_basic_block (b); |
705 | } | |
b8698a0f | 706 | |
6fb5fa3c DB |
707 | tidy_fallthru_edges (); |
708 | } | |
709 | ||
6fb5fa3c DB |
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 | { | |
34e5c511 RB |
739 | auto_bitmap visited; |
740 | basic_block next = bb; | |
6fb5fa3c DB |
741 | |
742 | for (;;) | |
743 | { | |
34e5c511 RB |
744 | if (EDGE_COUNT (next->succs) == 0) |
745 | return next; | |
6fb5fa3c | 746 | |
34e5c511 RB |
747 | if (! bitmap_set_bit (visited, next->index)) |
748 | return bb; | |
749 | ||
750 | bb = next; | |
44ab146a RB |
751 | /* If we are in an analyzed cycle make sure to try exiting it. |
752 | Note this is a heuristic only and expected to work when loop | |
753 | fixup is needed as well. */ | |
754 | if (! bb->loop_father | |
755 | || ! loop_outer (bb->loop_father)) | |
34e5c511 | 756 | next = EDGE_SUCC (bb, 0)->dest; |
44ab146a RB |
757 | else |
758 | { | |
759 | edge_iterator ei; | |
760 | edge e; | |
761 | FOR_EACH_EDGE (e, ei, bb->succs) | |
762 | if (loop_exit_edge_p (bb->loop_father, e)) | |
763 | break; | |
34e5c511 | 764 | next = e ? e->dest : EDGE_SUCC (bb, 0)->dest; |
44ab146a | 765 | } |
6fb5fa3c DB |
766 | } |
767 | ||
768 | gcc_unreachable (); | |
769 | } | |
770 | ||
771 | ||
772 | /* Compute the reverse top sort order of the inverted CFG | |
773 | i.e. starting from the exit block and following the edges backward | |
774 | (from successors to predecessors). | |
775 | This ordering can be used for forward dataflow problems among others. | |
776 | ||
e4dbb0d4 JH |
777 | Optionally if START_POINTS is specified, start from exit block and all |
778 | basic blocks in START_POINTS. This is used by CD-DCE. | |
779 | ||
6fb5fa3c DB |
780 | This function assumes that all blocks in the CFG are reachable |
781 | from the ENTRY (but not necessarily from EXIT). | |
782 | ||
783 | If there's an infinite loop, | |
784 | a simple inverted traversal starting from the blocks | |
785 | with no successors can't visit all blocks. | |
786 | To solve this problem, we first do inverted traversal | |
787 | starting from the blocks with no successor. | |
b8698a0f | 788 | And if there's any block left that's not visited by the regular |
6fb5fa3c DB |
789 | inverted traversal from EXIT, |
790 | those blocks are in such problematic region. | |
b8698a0f | 791 | Among those, we find one block that has |
6fb5fa3c | 792 | any visited predecessor (which is an entry into such a region), |
b8698a0f | 793 | and start looking for a "dead end" from that block |
6fb5fa3c DB |
794 | and do another inverted traversal from that block. */ |
795 | ||
6fa95e09 TS |
796 | void |
797 | inverted_post_order_compute (vec<int> *post_order, | |
e4dbb0d4 | 798 | sbitmap *start_points) |
6fb5fa3c DB |
799 | { |
800 | basic_block bb; | |
6fa95e09 | 801 | post_order->reserve_exact (n_basic_blocks_for_fn (cfun)); |
6fb5fa3c | 802 | |
a6c764d0 MM |
803 | if (flag_checking) |
804 | verify_no_unreachable_blocks (); | |
a352b710 | 805 | |
6fb5fa3c | 806 | /* Allocate stack for back-tracking up CFG. */ |
792bb49b | 807 | auto_vec<edge_iterator, 20> stack (n_basic_blocks_for_fn (cfun) + 1); |
6fb5fa3c DB |
808 | |
809 | /* Allocate bitmap to track nodes that have been visited. */ | |
7ba9e72d | 810 | auto_sbitmap visited (last_basic_block_for_fn (cfun)); |
6fb5fa3c DB |
811 | |
812 | /* None of the nodes in the CFG have been visited yet. */ | |
f61e445a | 813 | bitmap_clear (visited); |
6fb5fa3c | 814 | |
e4dbb0d4 JH |
815 | if (start_points) |
816 | { | |
817 | FOR_ALL_BB_FN (bb, cfun) | |
818 | if (bitmap_bit_p (*start_points, bb->index) | |
819 | && EDGE_COUNT (bb->preds) > 0) | |
820 | { | |
792bb49b | 821 | stack.quick_push (ei_start (bb->preds)); |
e4dbb0d4 JH |
822 | bitmap_set_bit (visited, bb->index); |
823 | } | |
824 | if (EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds)) | |
825 | { | |
792bb49b | 826 | stack.quick_push (ei_start (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds)); |
e4dbb0d4 JH |
827 | bitmap_set_bit (visited, EXIT_BLOCK_PTR_FOR_FN (cfun)->index); |
828 | } | |
829 | } | |
830 | else | |
6fb5fa3c | 831 | /* Put all blocks that have no successor into the initial work list. */ |
04a90bec | 832 | FOR_ALL_BB_FN (bb, cfun) |
6fb5fa3c DB |
833 | if (EDGE_COUNT (bb->succs) == 0) |
834 | { | |
835 | /* Push the initial edge on to the stack. */ | |
b8698a0f | 836 | if (EDGE_COUNT (bb->preds) > 0) |
6fb5fa3c | 837 | { |
792bb49b | 838 | stack.quick_push (ei_start (bb->preds)); |
d7c028c0 | 839 | bitmap_set_bit (visited, bb->index); |
6fb5fa3c DB |
840 | } |
841 | } | |
842 | ||
b8698a0f | 843 | do |
6fb5fa3c DB |
844 | { |
845 | bool has_unvisited_bb = false; | |
846 | ||
847 | /* The inverted traversal loop. */ | |
792bb49b | 848 | while (!stack.is_empty ()) |
6fb5fa3c DB |
849 | { |
850 | edge_iterator ei; | |
851 | basic_block pred; | |
852 | ||
853 | /* Look at the edge on the top of the stack. */ | |
792bb49b | 854 | ei = stack.last (); |
6fb5fa3c DB |
855 | bb = ei_edge (ei)->dest; |
856 | pred = ei_edge (ei)->src; | |
857 | ||
858 | /* Check if the predecessor has been visited yet. */ | |
d7c028c0 | 859 | if (! bitmap_bit_p (visited, pred->index)) |
6fb5fa3c DB |
860 | { |
861 | /* Mark that we have visited the destination. */ | |
d7c028c0 | 862 | bitmap_set_bit (visited, pred->index); |
6fb5fa3c DB |
863 | |
864 | if (EDGE_COUNT (pred->preds) > 0) | |
865 | /* Since the predecessor node has been visited for the first | |
866 | time, check its predecessors. */ | |
792bb49b | 867 | stack.quick_push (ei_start (pred->preds)); |
6fb5fa3c | 868 | else |
6fa95e09 | 869 | post_order->quick_push (pred->index); |
6fb5fa3c DB |
870 | } |
871 | else | |
872 | { | |
fefa31b5 DM |
873 | if (bb != EXIT_BLOCK_PTR_FOR_FN (cfun) |
874 | && ei_one_before_end_p (ei)) | |
6fa95e09 | 875 | post_order->quick_push (bb->index); |
6fb5fa3c DB |
876 | |
877 | if (!ei_one_before_end_p (ei)) | |
792bb49b | 878 | ei_next (&stack.last ()); |
6fb5fa3c | 879 | else |
792bb49b | 880 | stack.pop (); |
6fb5fa3c DB |
881 | } |
882 | } | |
883 | ||
b8698a0f | 884 | /* Detect any infinite loop and activate the kludge. |
6fb5fa3c | 885 | Note that this doesn't check EXIT_BLOCK itself |
792bb49b | 886 | since EXIT_BLOCK is always added after the outer do-while loop. */ |
fefa31b5 DM |
887 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), |
888 | EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb) | |
d7c028c0 | 889 | if (!bitmap_bit_p (visited, bb->index)) |
6fb5fa3c DB |
890 | { |
891 | has_unvisited_bb = true; | |
892 | ||
893 | if (EDGE_COUNT (bb->preds) > 0) | |
894 | { | |
895 | edge_iterator ei; | |
896 | edge e; | |
897 | basic_block visited_pred = NULL; | |
898 | ||
899 | /* Find an already visited predecessor. */ | |
900 | FOR_EACH_EDGE (e, ei, bb->preds) | |
901 | { | |
d7c028c0 | 902 | if (bitmap_bit_p (visited, e->src->index)) |
6fb5fa3c DB |
903 | visited_pred = e->src; |
904 | } | |
905 | ||
906 | if (visited_pred) | |
907 | { | |
908 | basic_block be = dfs_find_deadend (bb); | |
909 | gcc_assert (be != NULL); | |
d7c028c0 | 910 | bitmap_set_bit (visited, be->index); |
792bb49b | 911 | stack.quick_push (ei_start (be->preds)); |
6fb5fa3c DB |
912 | break; |
913 | } | |
914 | } | |
915 | } | |
916 | ||
792bb49b | 917 | if (has_unvisited_bb && stack.is_empty ()) |
6fb5fa3c | 918 | { |
792bb49b | 919 | /* No blocks are reachable from EXIT at all. |
6fb5fa3c | 920 | Find a dead-end from the ENTRY, and restart the iteration. */ |
fefa31b5 | 921 | basic_block be = dfs_find_deadend (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
6fb5fa3c | 922 | gcc_assert (be != NULL); |
d7c028c0 | 923 | bitmap_set_bit (visited, be->index); |
792bb49b | 924 | stack.quick_push (ei_start (be->preds)); |
6fb5fa3c DB |
925 | } |
926 | ||
b8698a0f | 927 | /* The only case the below while fires is |
6fb5fa3c DB |
928 | when there's an infinite loop. */ |
929 | } | |
792bb49b | 930 | while (!stack.is_empty ()); |
6fb5fa3c DB |
931 | |
932 | /* EXIT_BLOCK is always included. */ | |
6fa95e09 | 933 | post_order->quick_push (EXIT_BLOCK); |
402209ff JH |
934 | } |
935 | ||
1bef9b23 RB |
936 | /* Compute the depth first search order of FN and store in the array |
937 | PRE_ORDER if nonzero. If REV_POST_ORDER is nonzero, return the | |
938 | reverse completion number for each node. Returns the number of nodes | |
939 | visited. A depth first search tries to get as far away from the starting | |
940 | point as quickly as possible. | |
f91a0beb | 941 | |
1bef9b23 RB |
942 | In case the function has unreachable blocks the number of nodes |
943 | visited does not include them. | |
944 | ||
945 | pre_order is a really a preorder numbering of the graph. | |
946 | rev_post_order is really a reverse postorder numbering of the graph. */ | |
402209ff JH |
947 | |
948 | int | |
1bef9b23 RB |
949 | pre_and_rev_post_order_compute_fn (struct function *fn, |
950 | int *pre_order, int *rev_post_order, | |
951 | bool include_entry_exit) | |
402209ff | 952 | { |
f91a0beb | 953 | int pre_order_num = 0; |
1c93f6ce | 954 | int rev_post_order_num = n_basic_blocks_for_fn (fn) - 1; |
402209ff JH |
955 | |
956 | /* Allocate stack for back-tracking up CFG. */ | |
1c93f6ce | 957 | auto_vec<edge_iterator, 20> stack (n_basic_blocks_for_fn (fn) + 1); |
402209ff | 958 | |
f91a0beb KZ |
959 | if (include_entry_exit) |
960 | { | |
961 | if (pre_order) | |
962 | pre_order[pre_order_num] = ENTRY_BLOCK; | |
963 | pre_order_num++; | |
964 | if (rev_post_order) | |
e5f95b66 | 965 | rev_post_order[rev_post_order_num--] = EXIT_BLOCK; |
f91a0beb | 966 | } |
b8698a0f | 967 | else |
f91a0beb KZ |
968 | rev_post_order_num -= NUM_FIXED_BLOCKS; |
969 | ||
5a34952e RB |
970 | /* BB flag to track nodes that have been visited. */ |
971 | auto_bb_flag visited (fn); | |
402209ff JH |
972 | |
973 | /* Push the first edge on to the stack. */ | |
792bb49b | 974 | stack.quick_push (ei_start (ENTRY_BLOCK_PTR_FOR_FN (fn)->succs)); |
402209ff | 975 | |
792bb49b | 976 | while (!stack.is_empty ()) |
402209ff | 977 | { |
402209ff JH |
978 | basic_block src; |
979 | basic_block dest; | |
980 | ||
981 | /* Look at the edge on the top of the stack. */ | |
792bb49b | 982 | edge_iterator ei = stack.last (); |
628f6a4e BE |
983 | src = ei_edge (ei)->src; |
984 | dest = ei_edge (ei)->dest; | |
402209ff JH |
985 | |
986 | /* Check if the edge destination has been visited yet. */ | |
fefa31b5 | 987 | if (dest != EXIT_BLOCK_PTR_FOR_FN (fn) |
5a34952e | 988 | && ! (dest->flags & visited)) |
402209ff JH |
989 | { |
990 | /* Mark that we have visited the destination. */ | |
5a34952e | 991 | dest->flags |= visited; |
402209ff | 992 | |
f91a0beb KZ |
993 | if (pre_order) |
994 | pre_order[pre_order_num] = dest->index; | |
f5f53ae3 | 995 | |
f91a0beb | 996 | pre_order_num++; |
402209ff | 997 | |
628f6a4e | 998 | if (EDGE_COUNT (dest->succs) > 0) |
4891442b RK |
999 | /* Since the DEST node has been visited for the first |
1000 | time, check its successors. */ | |
792bb49b | 1001 | stack.quick_push (ei_start (dest->succs)); |
f91a0beb | 1002 | else if (rev_post_order) |
4891442b RK |
1003 | /* There are no successors for the DEST node so assign |
1004 | its reverse completion number. */ | |
f91a0beb | 1005 | rev_post_order[rev_post_order_num--] = dest->index; |
402209ff JH |
1006 | } |
1007 | else | |
1008 | { | |
1bef9b23 | 1009 | if (ei_one_before_end_p (ei) |
fefa31b5 | 1010 | && src != ENTRY_BLOCK_PTR_FOR_FN (fn) |
f91a0beb | 1011 | && rev_post_order) |
4891442b RK |
1012 | /* There are no more successors for the SRC node |
1013 | so assign its reverse completion number. */ | |
f91a0beb | 1014 | rev_post_order[rev_post_order_num--] = src->index; |
402209ff | 1015 | |
628f6a4e | 1016 | if (!ei_one_before_end_p (ei)) |
792bb49b | 1017 | ei_next (&stack.last ()); |
402209ff | 1018 | else |
792bb49b | 1019 | stack.pop (); |
402209ff JH |
1020 | } |
1021 | } | |
1022 | ||
f91a0beb KZ |
1023 | if (include_entry_exit) |
1024 | { | |
1025 | if (pre_order) | |
1026 | pre_order[pre_order_num] = EXIT_BLOCK; | |
1027 | pre_order_num++; | |
1028 | if (rev_post_order) | |
e5f95b66 | 1029 | rev_post_order[rev_post_order_num--] = ENTRY_BLOCK; |
f91a0beb | 1030 | } |
1bef9b23 | 1031 | |
5a34952e | 1032 | /* Clear the temporarily allocated flag. */ |
1e89ab6c RB |
1033 | if (!rev_post_order) |
1034 | rev_post_order = pre_order; | |
5a34952e RB |
1035 | for (int i = 0; i < pre_order_num; ++i) |
1036 | BASIC_BLOCK_FOR_FN (fn, rev_post_order[i])->flags &= ~visited; | |
1037 | ||
1bef9b23 RB |
1038 | return pre_order_num; |
1039 | } | |
1040 | ||
1041 | /* Like pre_and_rev_post_order_compute_fn but operating on the | |
1042 | current function and asserting that all nodes were visited. */ | |
1043 | ||
1044 | int | |
1045 | pre_and_rev_post_order_compute (int *pre_order, int *rev_post_order, | |
1046 | bool include_entry_exit) | |
1047 | { | |
1048 | int pre_order_num | |
1049 | = pre_and_rev_post_order_compute_fn (cfun, pre_order, rev_post_order, | |
1050 | include_entry_exit); | |
1051 | if (include_entry_exit) | |
1052 | /* The number of nodes visited should be the number of blocks. */ | |
0cae8d31 | 1053 | gcc_assert (pre_order_num == n_basic_blocks_for_fn (cfun)); |
f91a0beb KZ |
1054 | else |
1055 | /* The number of nodes visited should be the number of blocks minus | |
1056 | the entry and exit blocks which are not visited here. */ | |
0cae8d31 DM |
1057 | gcc_assert (pre_order_num |
1058 | == (n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS)); | |
4891442b | 1059 | |
f91a0beb | 1060 | return pre_order_num; |
402209ff JH |
1061 | } |
1062 | ||
78ea9abc RB |
1063 | /* Unlike pre_and_rev_post_order_compute we fill rev_post_order backwards |
1064 | so iterating in RPO order needs to start with rev_post_order[n - 1] | |
1065 | going to rev_post_order[0]. If FOR_ITERATION is true then try to | |
1066 | make CFG cycles fit into small contiguous regions of the RPO order. | |
1067 | When FOR_ITERATION is true this requires up-to-date loop structures. */ | |
1068 | ||
1069 | int | |
1070 | rev_post_order_and_mark_dfs_back_seme (struct function *fn, edge entry, | |
1071 | bitmap exit_bbs, bool for_iteration, | |
1072 | int *rev_post_order) | |
1073 | { | |
1074 | int pre_order_num = 0; | |
1075 | int rev_post_order_num = 0; | |
1076 | ||
1077 | /* Allocate stack for back-tracking up CFG. Worst case we need | |
1078 | O(n^2) edges but the following should suffice in practice without | |
1079 | a need to re-allocate. */ | |
1080 | auto_vec<edge, 20> stack (2 * n_basic_blocks_for_fn (fn)); | |
1081 | ||
1082 | int *pre = XNEWVEC (int, 2 * last_basic_block_for_fn (fn)); | |
1083 | int *post = pre + last_basic_block_for_fn (fn); | |
1084 | ||
1085 | /* BB flag to track nodes that have been visited. */ | |
1086 | auto_bb_flag visited (fn); | |
1087 | /* BB flag to track which nodes have post[] assigned to avoid | |
1088 | zeroing post. */ | |
1089 | auto_bb_flag post_assigned (fn); | |
1090 | ||
1091 | /* Push the first edge on to the stack. */ | |
1092 | stack.quick_push (entry); | |
1093 | ||
1094 | while (!stack.is_empty ()) | |
1095 | { | |
1096 | basic_block src; | |
1097 | basic_block dest; | |
1098 | ||
1099 | /* Look at the edge on the top of the stack. */ | |
1100 | int idx = stack.length () - 1; | |
1101 | edge e = stack[idx]; | |
1102 | src = e->src; | |
1103 | dest = e->dest; | |
1104 | e->flags &= ~EDGE_DFS_BACK; | |
1105 | ||
1106 | /* Check if the edge destination has been visited yet. */ | |
1107 | if (! bitmap_bit_p (exit_bbs, dest->index) | |
1108 | && ! (dest->flags & visited)) | |
1109 | { | |
1110 | /* Mark that we have visited the destination. */ | |
1111 | dest->flags |= visited; | |
1112 | ||
1113 | pre[dest->index] = pre_order_num++; | |
1114 | ||
1115 | if (EDGE_COUNT (dest->succs) > 0) | |
1116 | { | |
1117 | /* Since the DEST node has been visited for the first | |
1118 | time, check its successors. */ | |
1119 | /* Push the edge vector in reverse to match previous behavior. */ | |
1120 | stack.reserve (EDGE_COUNT (dest->succs)); | |
1121 | for (int i = EDGE_COUNT (dest->succs) - 1; i >= 0; --i) | |
1122 | stack.quick_push (EDGE_SUCC (dest, i)); | |
1123 | /* Generalize to handle more successors? */ | |
1124 | if (for_iteration | |
1125 | && EDGE_COUNT (dest->succs) == 2) | |
1126 | { | |
1127 | edge &e1 = stack[stack.length () - 2]; | |
1128 | if (loop_exit_edge_p (e1->src->loop_father, e1)) | |
1129 | std::swap (e1, stack.last ()); | |
1130 | } | |
1131 | } | |
1132 | else | |
1133 | { | |
1134 | /* There are no successors for the DEST node so assign | |
1135 | its reverse completion number. */ | |
1136 | post[dest->index] = rev_post_order_num; | |
1137 | dest->flags |= post_assigned; | |
1138 | rev_post_order[rev_post_order_num] = dest->index; | |
1139 | rev_post_order_num++; | |
1140 | } | |
1141 | } | |
1142 | else | |
1143 | { | |
1144 | if (dest->flags & visited | |
1145 | && src != entry->src | |
1146 | && pre[src->index] >= pre[dest->index] | |
1147 | && !(dest->flags & post_assigned)) | |
1148 | e->flags |= EDGE_DFS_BACK; | |
1149 | ||
1150 | if (idx != 0 && stack[idx - 1]->src != src) | |
1151 | { | |
1152 | /* There are no more successors for the SRC node | |
1153 | so assign its reverse completion number. */ | |
1154 | post[src->index] = rev_post_order_num; | |
1155 | src->flags |= post_assigned; | |
1156 | rev_post_order[rev_post_order_num] = src->index; | |
1157 | rev_post_order_num++; | |
1158 | } | |
1159 | ||
1160 | stack.pop (); | |
1161 | } | |
1162 | } | |
1163 | ||
1164 | XDELETEVEC (pre); | |
1165 | ||
1166 | /* Clear the temporarily allocated flags. */ | |
1167 | for (int i = 0; i < rev_post_order_num; ++i) | |
1168 | BASIC_BLOCK_FOR_FN (fn, rev_post_order[i])->flags | |
1169 | &= ~(post_assigned|visited); | |
1170 | ||
1171 | return rev_post_order_num; | |
1172 | } | |
1173 | ||
1174 | ||
1175 | ||
402209ff | 1176 | /* Compute the depth first search order on the _reverse_ graph and |
78ea9abc | 1177 | store it in the array DFS_ORDER, marking the nodes visited in VISITED. |
402209ff JH |
1178 | Returns the number of nodes visited. |
1179 | ||
1180 | The computation is split into three pieces: | |
1181 | ||
1182 | flow_dfs_compute_reverse_init () creates the necessary data | |
1183 | structures. | |
1184 | ||
1185 | flow_dfs_compute_reverse_add_bb () adds a basic block to the data | |
1186 | structures. The block will start the search. | |
1187 | ||
1188 | flow_dfs_compute_reverse_execute () continues (or starts) the | |
1189 | search using the block on the top of the stack, stopping when the | |
1190 | stack is empty. | |
1191 | ||
1192 | flow_dfs_compute_reverse_finish () destroys the necessary data | |
1193 | structures. | |
1194 | ||
1195 | Thus, the user will probably call ..._init(), call ..._add_bb() to | |
1196 | add a beginning basic block to the stack, call ..._execute(), | |
1197 | possibly add another bb to the stack and again call ..._execute(), | |
1198 | ..., and finally call _finish(). */ | |
1199 | ||
1200 | /* Initialize the data structures used for depth-first search on the | |
1201 | reverse graph. If INITIALIZE_STACK is nonzero, the exit block is | |
1202 | added to the basic block stack. DATA is the current depth-first | |
da7d8304 | 1203 | search context. If INITIALIZE_STACK is nonzero, there is an |
402209ff JH |
1204 | element on the stack. */ |
1205 | ||
35bfaf4d TS |
1206 | depth_first_search::depth_first_search () : |
1207 | m_stack (n_basic_blocks_for_fn (cfun)), | |
1208 | m_visited_blocks (last_basic_block_for_fn (cfun)) | |
402209ff | 1209 | { |
35bfaf4d | 1210 | bitmap_clear (m_visited_blocks); |
402209ff JH |
1211 | } |
1212 | ||
1213 | /* Add the specified basic block to the top of the dfs data | |
1214 | structures. When the search continues, it will start at the | |
1215 | block. */ | |
1216 | ||
35bfaf4d TS |
1217 | void |
1218 | depth_first_search::add_bb (basic_block bb) | |
402209ff | 1219 | { |
35bfaf4d TS |
1220 | m_stack.quick_push (bb); |
1221 | bitmap_set_bit (m_visited_blocks, bb->index); | |
402209ff JH |
1222 | } |
1223 | ||
4891442b RK |
1224 | /* Continue the depth-first search through the reverse graph starting with the |
1225 | block at the stack's top and ending when the stack is empty. Visited nodes | |
1226 | are marked. Returns an unvisited basic block, or NULL if there is none | |
1227 | available. */ | |
402209ff | 1228 | |
35bfaf4d TS |
1229 | basic_block |
1230 | depth_first_search::execute (basic_block last_unvisited) | |
402209ff JH |
1231 | { |
1232 | basic_block bb; | |
1233 | edge e; | |
628f6a4e | 1234 | edge_iterator ei; |
402209ff | 1235 | |
35bfaf4d | 1236 | while (!m_stack.is_empty ()) |
402209ff | 1237 | { |
35bfaf4d | 1238 | bb = m_stack.pop (); |
4891442b | 1239 | |
db4a8254 | 1240 | /* Perform depth-first search on adjacent vertices. */ |
628f6a4e | 1241 | FOR_EACH_EDGE (e, ei, bb->preds) |
35bfaf4d TS |
1242 | if (!bitmap_bit_p (m_visited_blocks, e->src->index)) |
1243 | add_bb (e->src); | |
402209ff JH |
1244 | } |
1245 | ||
1246 | /* Determine if there are unvisited basic blocks. */ | |
24c75ec6 | 1247 | FOR_BB_BETWEEN (bb, last_unvisited, NULL, prev_bb) |
35bfaf4d | 1248 | if (!bitmap_bit_p (m_visited_blocks, bb->index)) |
d7bd989c | 1249 | return bb; |
4891442b | 1250 | |
402209ff JH |
1251 | return NULL; |
1252 | } | |
1253 | ||
2ecfd709 ZD |
1254 | /* Performs dfs search from BB over vertices satisfying PREDICATE; |
1255 | if REVERSE, go against direction of edges. Returns number of blocks | |
1256 | found and their list in RSLT. RSLT can contain at most RSLT_MAX items. */ | |
1257 | int | |
d329e058 | 1258 | dfs_enumerate_from (basic_block bb, int reverse, |
ed7a4b4b KG |
1259 | bool (*predicate) (const_basic_block, const void *), |
1260 | basic_block *rslt, int rslt_max, const void *data) | |
2ecfd709 ZD |
1261 | { |
1262 | basic_block *st, lbb; | |
1263 | int sp = 0, tv = 0; | |
9e32d2be | 1264 | |
e144a2b3 | 1265 | auto_bb_flag visited (cfun); |
9e32d2be | 1266 | |
e144a2b3 RB |
1267 | #define MARK_VISITED(BB) ((BB)->flags |= visited) |
1268 | #define UNMARK_VISITED(BB) ((BB)->flags &= ~visited) | |
1269 | #define VISITED_P(BB) (((BB)->flags & visited) != 0) | |
2ecfd709 | 1270 | |
c302207e | 1271 | st = XNEWVEC (basic_block, rslt_max); |
2ecfd709 | 1272 | rslt[tv++] = st[sp++] = bb; |
9e32d2be | 1273 | MARK_VISITED (bb); |
2ecfd709 ZD |
1274 | while (sp) |
1275 | { | |
1276 | edge e; | |
628f6a4e | 1277 | edge_iterator ei; |
2ecfd709 ZD |
1278 | lbb = st[--sp]; |
1279 | if (reverse) | |
c22cacf3 | 1280 | { |
628f6a4e | 1281 | FOR_EACH_EDGE (e, ei, lbb->preds) |
9e32d2be | 1282 | if (!VISITED_P (e->src) && predicate (e->src, data)) |
2ecfd709 | 1283 | { |
c22cacf3 MS |
1284 | gcc_assert (tv != rslt_max); |
1285 | rslt[tv++] = st[sp++] = e->src; | |
1286 | MARK_VISITED (e->src); | |
2ecfd709 | 1287 | } |
c22cacf3 | 1288 | } |
2ecfd709 | 1289 | else |
c22cacf3 | 1290 | { |
628f6a4e | 1291 | FOR_EACH_EDGE (e, ei, lbb->succs) |
9e32d2be | 1292 | if (!VISITED_P (e->dest) && predicate (e->dest, data)) |
2ecfd709 | 1293 | { |
c22cacf3 MS |
1294 | gcc_assert (tv != rslt_max); |
1295 | rslt[tv++] = st[sp++] = e->dest; | |
1296 | MARK_VISITED (e->dest); | |
2ecfd709 ZD |
1297 | } |
1298 | } | |
1299 | } | |
1300 | free (st); | |
1301 | for (sp = 0; sp < tv; sp++) | |
9e32d2be | 1302 | UNMARK_VISITED (rslt[sp]); |
2ecfd709 | 1303 | return tv; |
9e32d2be ZD |
1304 | #undef MARK_VISITED |
1305 | #undef UNMARK_VISITED | |
1306 | #undef VISITED_P | |
2ecfd709 | 1307 | } |
bd454efd SB |
1308 | |
1309 | ||
4c7f5fea | 1310 | /* Compute dominance frontiers, ala Harvey, Ferrante, et al. |
c22cacf3 | 1311 | |
4c7f5fea | 1312 | This algorithm can be found in Timothy Harvey's PhD thesis, at |
708bde14 | 1313 | http://www.cs.rice.edu/~harv/dissertation.pdf in the section on iterative |
4c7f5fea | 1314 | dominance algorithms. |
bd454efd | 1315 | |
4c7f5fea | 1316 | First, we identify each join point, j (any node with more than one |
c22cacf3 | 1317 | incoming edge is a join point). |
bd454efd | 1318 | |
4c7f5fea | 1319 | We then examine each predecessor, p, of j and walk up the dominator tree |
c22cacf3 MS |
1320 | starting at p. |
1321 | ||
4c7f5fea DB |
1322 | We stop the walk when we reach j's immediate dominator - j is in the |
1323 | dominance frontier of each of the nodes in the walk, except for j's | |
1324 | immediate dominator. Intuitively, all of the rest of j's dominators are | |
1325 | shared by j's predecessors as well. | |
1326 | Since they dominate j, they will not have j in their dominance frontiers. | |
1327 | ||
c22cacf3 | 1328 | The number of nodes touched by this algorithm is equal to the size |
4c7f5fea DB |
1329 | of the dominance frontiers, no more, no less. |
1330 | */ | |
bd454efd | 1331 | |
d78b7095 RB |
1332 | void |
1333 | compute_dominance_frontiers (bitmap_head *frontiers) | |
bd454efd | 1334 | { |
d78b7095 RB |
1335 | timevar_push (TV_DOM_FRONTIERS); |
1336 | ||
4c7f5fea | 1337 | edge p; |
628f6a4e | 1338 | edge_iterator ei; |
4c7f5fea | 1339 | basic_block b; |
11cd3bed | 1340 | FOR_EACH_BB_FN (b, cfun) |
bd454efd | 1341 | { |
4c7f5fea | 1342 | if (EDGE_COUNT (b->preds) >= 2) |
bd454efd | 1343 | { |
d78b7095 | 1344 | basic_block domsb = get_immediate_dominator (CDI_DOMINATORS, b); |
4c7f5fea DB |
1345 | FOR_EACH_EDGE (p, ei, b->preds) |
1346 | { | |
1347 | basic_block runner = p->src; | |
fefa31b5 | 1348 | if (runner == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
4c7f5fea | 1349 | continue; |
c22cacf3 | 1350 | |
4c7f5fea DB |
1351 | while (runner != domsb) |
1352 | { | |
d78b7095 | 1353 | if (!bitmap_set_bit (&frontiers[runner->index], b->index)) |
26eeea94 | 1354 | break; |
d78b7095 | 1355 | runner = get_immediate_dominator (CDI_DOMINATORS, runner); |
4c7f5fea DB |
1356 | } |
1357 | } | |
87c476a2 | 1358 | } |
bd454efd | 1359 | } |
bd454efd SB |
1360 | |
1361 | timevar_pop (TV_DOM_FRONTIERS); | |
1362 | } | |
25e87727 SB |
1363 | |
1364 | /* Given a set of blocks with variable definitions (DEF_BLOCKS), | |
1365 | return a bitmap with all the blocks in the iterated dominance | |
1366 | frontier of the blocks in DEF_BLOCKS. DFS contains dominance | |
1367 | frontier information as returned by compute_dominance_frontiers. | |
1368 | ||
1369 | The resulting set of blocks are the potential sites where PHI nodes | |
1370 | are needed. The caller is responsible for freeing the memory | |
1371 | allocated for the return value. */ | |
1372 | ||
1373 | bitmap | |
0fc555fb | 1374 | compute_idf (bitmap def_blocks, bitmap_head *dfs) |
25e87727 SB |
1375 | { |
1376 | bitmap_iterator bi; | |
1377 | unsigned bb_index, i; | |
25e87727 SB |
1378 | bitmap phi_insertion_points; |
1379 | ||
25e87727 SB |
1380 | phi_insertion_points = BITMAP_ALLOC (NULL); |
1381 | ||
d78b7095 RB |
1382 | /* Seed the work set with all the blocks in DEF_BLOCKS. */ |
1383 | auto_bitmap work_set; | |
1384 | bitmap_copy (work_set, def_blocks); | |
1385 | bitmap_tree_view (work_set); | |
25e87727 | 1386 | |
d78b7095 | 1387 | /* Pop a block off the workset, add every block that appears in |
25e87727 | 1388 | the original block's DF that we have not already processed to |
d78b7095 RB |
1389 | the workset. Iterate until the workset is empty. Blocks |
1390 | which are added to the workset are potential sites for | |
25e87727 | 1391 | PHI nodes. */ |
d78b7095 | 1392 | while (!bitmap_empty_p (work_set)) |
25e87727 | 1393 | { |
d78b7095 RB |
1394 | /* The dominance frontier of a block is blocks after it so iterating |
1395 | on earlier blocks first is better. | |
1396 | ??? Basic blocks are by no means guaranteed to be ordered in | |
1397 | optimal order for this iteration. */ | |
1398 | bb_index = bitmap_first_set_bit (work_set); | |
1399 | bitmap_clear_bit (work_set, bb_index); | |
25e87727 SB |
1400 | |
1401 | /* Since the registration of NEW -> OLD name mappings is done | |
1402 | separately from the call to update_ssa, when updating the SSA | |
1403 | form, the basic blocks where new and/or old names are defined | |
1404 | may have disappeared by CFG cleanup calls. In this case, | |
1405 | we may pull a non-existing block from the work stack. */ | |
8b1c6fd7 DM |
1406 | gcc_checking_assert (bb_index |
1407 | < (unsigned) last_basic_block_for_fn (cfun)); | |
25e87727 | 1408 | |
0fc555fb | 1409 | EXECUTE_IF_AND_COMPL_IN_BITMAP (&dfs[bb_index], phi_insertion_points, |
25e87727 SB |
1410 | 0, i, bi) |
1411 | { | |
d78b7095 | 1412 | bitmap_set_bit (work_set, i); |
25e87727 SB |
1413 | bitmap_set_bit (phi_insertion_points, i); |
1414 | } | |
1415 | } | |
1416 | ||
25e87727 SB |
1417 | return phi_insertion_points; |
1418 | } | |
1419 | ||
3c2c4f22 SB |
1420 | /* Intersection and union of preds/succs for sbitmap based data flow |
1421 | solvers. All four functions defined below take the same arguments: | |
1422 | B is the basic block to perform the operation for. DST is the | |
1423 | target sbitmap, i.e. the result. SRC is an sbitmap vector of size | |
1424 | last_basic_block so that it can be indexed with basic block indices. | |
1425 | DST may be (but does not have to be) SRC[B->index]. */ | |
25e87727 | 1426 | |
3c2c4f22 SB |
1427 | /* Set the bitmap DST to the intersection of SRC of successors of |
1428 | basic block B. */ | |
1429 | ||
1430 | void | |
d7c028c0 | 1431 | bitmap_intersection_of_succs (sbitmap dst, sbitmap *src, basic_block b) |
3c2c4f22 SB |
1432 | { |
1433 | unsigned int set_size = dst->size; | |
1434 | edge e; | |
1435 | unsigned ix; | |
1436 | ||
3c2c4f22 SB |
1437 | for (e = NULL, ix = 0; ix < EDGE_COUNT (b->succs); ix++) |
1438 | { | |
1439 | e = EDGE_SUCC (b, ix); | |
fefa31b5 | 1440 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1441 | continue; |
1442 | ||
f61e445a | 1443 | bitmap_copy (dst, src[e->dest->index]); |
3c2c4f22 SB |
1444 | break; |
1445 | } | |
1446 | ||
1447 | if (e == 0) | |
f61e445a | 1448 | bitmap_ones (dst); |
3c2c4f22 SB |
1449 | else |
1450 | for (++ix; ix < EDGE_COUNT (b->succs); ix++) | |
1451 | { | |
1452 | unsigned int i; | |
1453 | SBITMAP_ELT_TYPE *p, *r; | |
1454 | ||
1455 | e = EDGE_SUCC (b, ix); | |
fefa31b5 | 1456 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1457 | continue; |
1458 | ||
1459 | p = src[e->dest->index]->elms; | |
1460 | r = dst->elms; | |
1461 | for (i = 0; i < set_size; i++) | |
1462 | *r++ &= *p++; | |
1463 | } | |
1464 | } | |
1465 | ||
1466 | /* Set the bitmap DST to the intersection of SRC of predecessors of | |
1467 | basic block B. */ | |
1468 | ||
1469 | void | |
d7c028c0 | 1470 | bitmap_intersection_of_preds (sbitmap dst, sbitmap *src, basic_block b) |
3c2c4f22 SB |
1471 | { |
1472 | unsigned int set_size = dst->size; | |
1473 | edge e; | |
1474 | unsigned ix; | |
1475 | ||
3c2c4f22 SB |
1476 | for (e = NULL, ix = 0; ix < EDGE_COUNT (b->preds); ix++) |
1477 | { | |
1478 | e = EDGE_PRED (b, ix); | |
fefa31b5 | 1479 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1480 | continue; |
1481 | ||
f61e445a | 1482 | bitmap_copy (dst, src[e->src->index]); |
3c2c4f22 SB |
1483 | break; |
1484 | } | |
1485 | ||
1486 | if (e == 0) | |
f61e445a | 1487 | bitmap_ones (dst); |
3c2c4f22 SB |
1488 | else |
1489 | for (++ix; ix < EDGE_COUNT (b->preds); ix++) | |
1490 | { | |
1491 | unsigned int i; | |
1492 | SBITMAP_ELT_TYPE *p, *r; | |
1493 | ||
1494 | e = EDGE_PRED (b, ix); | |
fefa31b5 | 1495 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1496 | continue; |
1497 | ||
1498 | p = src[e->src->index]->elms; | |
1499 | r = dst->elms; | |
1500 | for (i = 0; i < set_size; i++) | |
1501 | *r++ &= *p++; | |
1502 | } | |
1503 | } | |
1504 | ||
1505 | /* Set the bitmap DST to the union of SRC of successors of | |
1506 | basic block B. */ | |
1507 | ||
1508 | void | |
d7c028c0 | 1509 | bitmap_union_of_succs (sbitmap dst, sbitmap *src, basic_block b) |
3c2c4f22 SB |
1510 | { |
1511 | unsigned int set_size = dst->size; | |
1512 | edge e; | |
1513 | unsigned ix; | |
1514 | ||
3c2c4f22 SB |
1515 | for (ix = 0; ix < EDGE_COUNT (b->succs); ix++) |
1516 | { | |
1517 | e = EDGE_SUCC (b, ix); | |
fefa31b5 | 1518 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1519 | continue; |
1520 | ||
f61e445a | 1521 | bitmap_copy (dst, src[e->dest->index]); |
3c2c4f22 SB |
1522 | break; |
1523 | } | |
1524 | ||
1525 | if (ix == EDGE_COUNT (b->succs)) | |
f61e445a | 1526 | bitmap_clear (dst); |
3c2c4f22 SB |
1527 | else |
1528 | for (ix++; ix < EDGE_COUNT (b->succs); ix++) | |
1529 | { | |
1530 | unsigned int i; | |
1531 | SBITMAP_ELT_TYPE *p, *r; | |
1532 | ||
1533 | e = EDGE_SUCC (b, ix); | |
fefa31b5 | 1534 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1535 | continue; |
1536 | ||
1537 | p = src[e->dest->index]->elms; | |
1538 | r = dst->elms; | |
1539 | for (i = 0; i < set_size; i++) | |
1540 | *r++ |= *p++; | |
1541 | } | |
1542 | } | |
1543 | ||
1544 | /* Set the bitmap DST to the union of SRC of predecessors of | |
1545 | basic block B. */ | |
1546 | ||
1547 | void | |
d7c028c0 | 1548 | bitmap_union_of_preds (sbitmap dst, sbitmap *src, basic_block b) |
3c2c4f22 SB |
1549 | { |
1550 | unsigned int set_size = dst->size; | |
1551 | edge e; | |
1552 | unsigned ix; | |
1553 | ||
3c2c4f22 SB |
1554 | for (ix = 0; ix < EDGE_COUNT (b->preds); ix++) |
1555 | { | |
1556 | e = EDGE_PRED (b, ix); | |
fefa31b5 | 1557 | if (e->src== ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1558 | continue; |
1559 | ||
f61e445a | 1560 | bitmap_copy (dst, src[e->src->index]); |
3c2c4f22 SB |
1561 | break; |
1562 | } | |
1563 | ||
1564 | if (ix == EDGE_COUNT (b->preds)) | |
f61e445a | 1565 | bitmap_clear (dst); |
3c2c4f22 SB |
1566 | else |
1567 | for (ix++; ix < EDGE_COUNT (b->preds); ix++) | |
1568 | { | |
1569 | unsigned int i; | |
1570 | SBITMAP_ELT_TYPE *p, *r; | |
1571 | ||
1572 | e = EDGE_PRED (b, ix); | |
fefa31b5 | 1573 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
3c2c4f22 SB |
1574 | continue; |
1575 | ||
1576 | p = src[e->src->index]->elms; | |
1577 | r = dst->elms; | |
1578 | for (i = 0; i < set_size; i++) | |
1579 | *r++ |= *p++; | |
1580 | } | |
1581 | } | |
3d9c733e AM |
1582 | |
1583 | /* Returns the list of basic blocks in the function in an order that guarantees | |
1584 | that if a block X has just a single predecessor Y, then Y is after X in the | |
1585 | ordering. */ | |
1586 | ||
1587 | basic_block * | |
1588 | single_pred_before_succ_order (void) | |
1589 | { | |
1590 | basic_block x, y; | |
0cae8d31 DM |
1591 | basic_block *order = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun)); |
1592 | unsigned n = n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; | |
3d9c733e | 1593 | unsigned np, i; |
7ba9e72d | 1594 | auto_sbitmap visited (last_basic_block_for_fn (cfun)); |
3d9c733e AM |
1595 | |
1596 | #define MARK_VISITED(BB) (bitmap_set_bit (visited, (BB)->index)) | |
1597 | #define VISITED_P(BB) (bitmap_bit_p (visited, (BB)->index)) | |
1598 | ||
1599 | bitmap_clear (visited); | |
1600 | ||
fefa31b5 | 1601 | MARK_VISITED (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
11cd3bed | 1602 | FOR_EACH_BB_FN (x, cfun) |
3d9c733e AM |
1603 | { |
1604 | if (VISITED_P (x)) | |
1605 | continue; | |
1606 | ||
1607 | /* Walk the predecessors of x as long as they have precisely one | |
1608 | predecessor and add them to the list, so that they get stored | |
1609 | after x. */ | |
1610 | for (y = x, np = 1; | |
1611 | single_pred_p (y) && !VISITED_P (single_pred (y)); | |
1612 | y = single_pred (y)) | |
1613 | np++; | |
1614 | for (y = x, i = n - np; | |
1615 | single_pred_p (y) && !VISITED_P (single_pred (y)); | |
1616 | y = single_pred (y), i++) | |
1617 | { | |
1618 | order[i] = y; | |
1619 | MARK_VISITED (y); | |
1620 | } | |
1621 | order[i] = y; | |
1622 | MARK_VISITED (y); | |
1623 | ||
1624 | gcc_assert (i == n - 1); | |
1625 | n -= np; | |
1626 | } | |
1627 | ||
3d9c733e AM |
1628 | gcc_assert (n == 0); |
1629 | return order; | |
1630 | ||
1631 | #undef MARK_VISITED | |
1632 | #undef VISITED_P | |
1633 | } | |
2965f127 JL |
1634 | |
1635 | /* Ignoring loop backedges, if BB has precisely one incoming edge then | |
1636 | return that edge. Otherwise return NULL. | |
1637 | ||
1638 | When IGNORE_NOT_EXECUTABLE is true, also ignore edges that are not marked | |
1639 | as executable. */ | |
1640 | ||
1641 | edge | |
1642 | single_pred_edge_ignoring_loop_edges (basic_block bb, | |
1643 | bool ignore_not_executable) | |
1644 | { | |
1645 | edge retval = NULL; | |
1646 | edge e; | |
1647 | edge_iterator ei; | |
1648 | ||
1649 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1650 | { | |
1651 | /* A loop back edge can be identified by the destination of | |
1652 | the edge dominating the source of the edge. */ | |
1653 | if (dominated_by_p (CDI_DOMINATORS, e->src, e->dest)) | |
1654 | continue; | |
1655 | ||
1656 | /* We can safely ignore edges that are not executable. */ | |
1657 | if (ignore_not_executable | |
1658 | && (e->flags & EDGE_EXECUTABLE) == 0) | |
1659 | continue; | |
1660 | ||
1661 | /* If we have already seen a non-loop edge, then we must have | |
1662 | multiple incoming non-loop edges and thus we return NULL. */ | |
1663 | if (retval) | |
1664 | return NULL; | |
1665 | ||
1666 | /* This is the first non-loop incoming edge we have found. Record | |
1667 | it. */ | |
1668 | retval = e; | |
1669 | } | |
1670 | ||
1671 | return retval; | |
1672 | } |