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6de9cd9a DN |
1 | /* Control flow functions for trees. |
2 | Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc. | |
3 | Contributed by Diego Novillo <dnovillo@redhat.com> | |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2, or (at your option) | |
10 | any later version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING. If not, write to | |
19 | the Free Software Foundation, 59 Temple Place - Suite 330, | |
20 | Boston, MA 02111-1307, USA. */ | |
21 | ||
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
27 | #include "rtl.h" | |
28 | #include "tm_p.h" | |
29 | #include "hard-reg-set.h" | |
30 | #include "basic-block.h" | |
31 | #include "output.h" | |
32 | #include "errors.h" | |
33 | #include "flags.h" | |
34 | #include "function.h" | |
35 | #include "expr.h" | |
36 | #include "ggc.h" | |
37 | #include "langhooks.h" | |
38 | #include "diagnostic.h" | |
39 | #include "tree-flow.h" | |
40 | #include "timevar.h" | |
41 | #include "tree-dump.h" | |
42 | #include "tree-pass.h" | |
43 | #include "toplev.h" | |
44 | #include "except.h" | |
45 | #include "cfgloop.h" | |
42759f1e | 46 | #include "cfglayout.h" |
92b6dff3 | 47 | #include "hashtab.h" |
6de9cd9a DN |
48 | |
49 | /* This file contains functions for building the Control Flow Graph (CFG) | |
50 | for a function tree. */ | |
51 | ||
52 | /* Local declarations. */ | |
53 | ||
54 | /* Initial capacity for the basic block array. */ | |
55 | static const int initial_cfg_capacity = 20; | |
56 | ||
57 | /* Mapping of labels to their associated blocks. This can greatly speed up | |
58 | building of the CFG in code with lots of gotos. */ | |
59 | static GTY(()) varray_type label_to_block_map; | |
60 | ||
d6be0d7f JL |
61 | /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs |
62 | which use a particular edge. The CASE_LABEL_EXPRs are chained together | |
63 | via their TREE_CHAIN field, which we clear after we're done with the | |
64 | hash table to prevent problems with duplication of SWITCH_EXPRs. | |
92b6dff3 | 65 | |
d6be0d7f JL |
66 | Access to this list of CASE_LABEL_EXPRs allows us to efficiently |
67 | update the case vector in response to edge redirections. | |
92b6dff3 | 68 | |
d6be0d7f JL |
69 | Right now this table is set up and torn down at key points in the |
70 | compilation process. It would be nice if we could make the table | |
71 | more persistent. The key is getting notification of changes to | |
72 | the CFG (particularly edge removal, creation and redirection). */ | |
73 | ||
74 | struct edge_to_cases_elt | |
92b6dff3 JL |
75 | { |
76 | /* The edge itself. Necessary for hashing and equality tests. */ | |
77 | edge e; | |
78 | ||
d6be0d7f JL |
79 | /* The case labels associated with this edge. We link these up via |
80 | their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields | |
81 | when we destroy the hash table. This prevents problems when copying | |
82 | SWITCH_EXPRs. */ | |
83 | tree case_labels; | |
92b6dff3 JL |
84 | }; |
85 | ||
d6be0d7f | 86 | static htab_t edge_to_cases; |
92b6dff3 | 87 | |
6de9cd9a DN |
88 | /* CFG statistics. */ |
89 | struct cfg_stats_d | |
90 | { | |
91 | long num_merged_labels; | |
92 | }; | |
93 | ||
94 | static struct cfg_stats_d cfg_stats; | |
95 | ||
96 | /* Nonzero if we found a computed goto while building basic blocks. */ | |
97 | static bool found_computed_goto; | |
98 | ||
99 | /* Basic blocks and flowgraphs. */ | |
100 | static basic_block create_bb (void *, void *, basic_block); | |
101 | static void create_block_annotation (basic_block); | |
102 | static void free_blocks_annotations (void); | |
103 | static void clear_blocks_annotations (void); | |
104 | static void make_blocks (tree); | |
105 | static void factor_computed_gotos (void); | |
6de9cd9a DN |
106 | |
107 | /* Edges. */ | |
108 | static void make_edges (void); | |
109 | static void make_ctrl_stmt_edges (basic_block); | |
110 | static void make_exit_edges (basic_block); | |
111 | static void make_cond_expr_edges (basic_block); | |
112 | static void make_switch_expr_edges (basic_block); | |
113 | static void make_goto_expr_edges (basic_block); | |
114 | static edge tree_redirect_edge_and_branch (edge, basic_block); | |
115 | static edge tree_try_redirect_by_replacing_jump (edge, basic_block); | |
116 | static void split_critical_edges (void); | |
117 | ||
118 | /* Various helpers. */ | |
119 | static inline bool stmt_starts_bb_p (tree, tree); | |
120 | static int tree_verify_flow_info (void); | |
121 | static void tree_make_forwarder_block (edge); | |
122 | static bool thread_jumps (void); | |
123 | static bool tree_forwarder_block_p (basic_block); | |
6de9cd9a DN |
124 | static void tree_cfg2vcg (FILE *); |
125 | ||
126 | /* Flowgraph optimization and cleanup. */ | |
127 | static void tree_merge_blocks (basic_block, basic_block); | |
128 | static bool tree_can_merge_blocks_p (basic_block, basic_block); | |
129 | static void remove_bb (basic_block); | |
6de9cd9a DN |
130 | static bool cleanup_control_flow (void); |
131 | static bool cleanup_control_expr_graph (basic_block, block_stmt_iterator); | |
132 | static edge find_taken_edge_cond_expr (basic_block, tree); | |
133 | static edge find_taken_edge_switch_expr (basic_block, tree); | |
134 | static tree find_case_label_for_value (tree, tree); | |
135 | static bool phi_alternatives_equal (basic_block, edge, edge); | |
136 | ||
137 | ||
138 | /*--------------------------------------------------------------------------- | |
139 | Create basic blocks | |
140 | ---------------------------------------------------------------------------*/ | |
141 | ||
142 | /* Entry point to the CFG builder for trees. TP points to the list of | |
143 | statements to be added to the flowgraph. */ | |
144 | ||
145 | static void | |
146 | build_tree_cfg (tree *tp) | |
147 | { | |
148 | /* Register specific tree functions. */ | |
149 | tree_register_cfg_hooks (); | |
150 | ||
151 | /* Initialize rbi_pool. */ | |
152 | alloc_rbi_pool (); | |
153 | ||
154 | /* Initialize the basic block array. */ | |
155 | init_flow (); | |
878f99d2 | 156 | profile_status = PROFILE_ABSENT; |
6de9cd9a DN |
157 | n_basic_blocks = 0; |
158 | last_basic_block = 0; | |
159 | VARRAY_BB_INIT (basic_block_info, initial_cfg_capacity, "basic_block_info"); | |
160 | memset ((void *) &cfg_stats, 0, sizeof (cfg_stats)); | |
161 | ||
162 | /* Build a mapping of labels to their associated blocks. */ | |
163 | VARRAY_BB_INIT (label_to_block_map, initial_cfg_capacity, | |
164 | "label to block map"); | |
165 | ||
166 | ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR; | |
167 | EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR; | |
168 | ||
169 | found_computed_goto = 0; | |
170 | make_blocks (*tp); | |
171 | ||
172 | /* Computed gotos are hell to deal with, especially if there are | |
173 | lots of them with a large number of destinations. So we factor | |
174 | them to a common computed goto location before we build the | |
175 | edge list. After we convert back to normal form, we will un-factor | |
176 | the computed gotos since factoring introduces an unwanted jump. */ | |
177 | if (found_computed_goto) | |
178 | factor_computed_gotos (); | |
179 | ||
f0b698c1 | 180 | /* Make sure there is always at least one block, even if it's empty. */ |
6de9cd9a DN |
181 | if (n_basic_blocks == 0) |
182 | create_empty_bb (ENTRY_BLOCK_PTR); | |
183 | ||
184 | create_block_annotation (ENTRY_BLOCK_PTR); | |
185 | create_block_annotation (EXIT_BLOCK_PTR); | |
186 | ||
187 | /* Adjust the size of the array. */ | |
188 | VARRAY_GROW (basic_block_info, n_basic_blocks); | |
189 | ||
f667741c SB |
190 | /* To speed up statement iterator walks, we first purge dead labels. */ |
191 | cleanup_dead_labels (); | |
192 | ||
193 | /* Group case nodes to reduce the number of edges. | |
194 | We do this after cleaning up dead labels because otherwise we miss | |
195 | a lot of obvious case merging opportunities. */ | |
196 | group_case_labels (); | |
197 | ||
6de9cd9a DN |
198 | /* Create the edges of the flowgraph. */ |
199 | make_edges (); | |
200 | ||
201 | /* Debugging dumps. */ | |
202 | ||
203 | /* Write the flowgraph to a VCG file. */ | |
204 | { | |
205 | int local_dump_flags; | |
206 | FILE *dump_file = dump_begin (TDI_vcg, &local_dump_flags); | |
207 | if (dump_file) | |
208 | { | |
209 | tree_cfg2vcg (dump_file); | |
210 | dump_end (TDI_vcg, dump_file); | |
211 | } | |
212 | } | |
213 | ||
214 | /* Dump a textual representation of the flowgraph. */ | |
215 | if (dump_file) | |
216 | dump_tree_cfg (dump_file, dump_flags); | |
217 | } | |
218 | ||
219 | static void | |
220 | execute_build_cfg (void) | |
221 | { | |
222 | build_tree_cfg (&DECL_SAVED_TREE (current_function_decl)); | |
223 | } | |
224 | ||
225 | struct tree_opt_pass pass_build_cfg = | |
226 | { | |
227 | "cfg", /* name */ | |
228 | NULL, /* gate */ | |
229 | execute_build_cfg, /* execute */ | |
230 | NULL, /* sub */ | |
231 | NULL, /* next */ | |
232 | 0, /* static_pass_number */ | |
233 | TV_TREE_CFG, /* tv_id */ | |
234 | PROP_gimple_leh, /* properties_required */ | |
235 | PROP_cfg, /* properties_provided */ | |
236 | 0, /* properties_destroyed */ | |
237 | 0, /* todo_flags_start */ | |
9f8628ba PB |
238 | TODO_verify_stmts, /* todo_flags_finish */ |
239 | 0 /* letter */ | |
6de9cd9a DN |
240 | }; |
241 | ||
242 | /* Search the CFG for any computed gotos. If found, factor them to a | |
243 | common computed goto site. Also record the location of that site so | |
244 | that we can un-factor the gotos after we have converted back to | |
245 | normal form. */ | |
246 | ||
247 | static void | |
248 | factor_computed_gotos (void) | |
249 | { | |
250 | basic_block bb; | |
251 | tree factored_label_decl = NULL; | |
252 | tree var = NULL; | |
253 | tree factored_computed_goto_label = NULL; | |
254 | tree factored_computed_goto = NULL; | |
255 | ||
256 | /* We know there are one or more computed gotos in this function. | |
257 | Examine the last statement in each basic block to see if the block | |
258 | ends with a computed goto. */ | |
259 | ||
260 | FOR_EACH_BB (bb) | |
261 | { | |
262 | block_stmt_iterator bsi = bsi_last (bb); | |
263 | tree last; | |
264 | ||
265 | if (bsi_end_p (bsi)) | |
266 | continue; | |
267 | last = bsi_stmt (bsi); | |
268 | ||
269 | /* Ignore the computed goto we create when we factor the original | |
270 | computed gotos. */ | |
271 | if (last == factored_computed_goto) | |
272 | continue; | |
273 | ||
274 | /* If the last statement is a computed goto, factor it. */ | |
275 | if (computed_goto_p (last)) | |
276 | { | |
277 | tree assignment; | |
278 | ||
279 | /* The first time we find a computed goto we need to create | |
280 | the factored goto block and the variable each original | |
281 | computed goto will use for their goto destination. */ | |
282 | if (! factored_computed_goto) | |
283 | { | |
284 | basic_block new_bb = create_empty_bb (bb); | |
285 | block_stmt_iterator new_bsi = bsi_start (new_bb); | |
286 | ||
287 | /* Create the destination of the factored goto. Each original | |
288 | computed goto will put its desired destination into this | |
289 | variable and jump to the label we create immediately | |
290 | below. */ | |
291 | var = create_tmp_var (ptr_type_node, "gotovar"); | |
292 | ||
293 | /* Build a label for the new block which will contain the | |
294 | factored computed goto. */ | |
295 | factored_label_decl = create_artificial_label (); | |
296 | factored_computed_goto_label | |
297 | = build1 (LABEL_EXPR, void_type_node, factored_label_decl); | |
298 | bsi_insert_after (&new_bsi, factored_computed_goto_label, | |
299 | BSI_NEW_STMT); | |
300 | ||
301 | /* Build our new computed goto. */ | |
302 | factored_computed_goto = build1 (GOTO_EXPR, void_type_node, var); | |
303 | bsi_insert_after (&new_bsi, factored_computed_goto, | |
304 | BSI_NEW_STMT); | |
305 | } | |
306 | ||
307 | /* Copy the original computed goto's destination into VAR. */ | |
308 | assignment = build (MODIFY_EXPR, ptr_type_node, | |
309 | var, GOTO_DESTINATION (last)); | |
310 | bsi_insert_before (&bsi, assignment, BSI_SAME_STMT); | |
311 | ||
312 | /* And re-vector the computed goto to the new destination. */ | |
313 | GOTO_DESTINATION (last) = factored_label_decl; | |
314 | } | |
315 | } | |
316 | } | |
317 | ||
318 | ||
319 | /* Create annotations for a single basic block. */ | |
320 | ||
321 | static void | |
322 | create_block_annotation (basic_block bb) | |
323 | { | |
324 | /* Verify that the tree_annotations field is clear. */ | |
1e128c5f | 325 | gcc_assert (!bb->tree_annotations); |
6de9cd9a DN |
326 | bb->tree_annotations = ggc_alloc_cleared (sizeof (struct bb_ann_d)); |
327 | } | |
328 | ||
329 | ||
330 | /* Free the annotations for all the basic blocks. */ | |
331 | ||
332 | static void free_blocks_annotations (void) | |
333 | { | |
334 | clear_blocks_annotations (); | |
335 | } | |
336 | ||
337 | ||
338 | /* Clear the annotations for all the basic blocks. */ | |
339 | ||
340 | static void | |
341 | clear_blocks_annotations (void) | |
342 | { | |
343 | basic_block bb; | |
344 | ||
345 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb) | |
346 | bb->tree_annotations = NULL; | |
347 | } | |
348 | ||
349 | ||
350 | /* Build a flowgraph for the statement_list STMT_LIST. */ | |
351 | ||
352 | static void | |
353 | make_blocks (tree stmt_list) | |
354 | { | |
355 | tree_stmt_iterator i = tsi_start (stmt_list); | |
356 | tree stmt = NULL; | |
357 | bool start_new_block = true; | |
358 | bool first_stmt_of_list = true; | |
359 | basic_block bb = ENTRY_BLOCK_PTR; | |
360 | ||
361 | while (!tsi_end_p (i)) | |
362 | { | |
363 | tree prev_stmt; | |
364 | ||
365 | prev_stmt = stmt; | |
366 | stmt = tsi_stmt (i); | |
367 | ||
368 | /* If the statement starts a new basic block or if we have determined | |
369 | in a previous pass that we need to create a new block for STMT, do | |
370 | so now. */ | |
371 | if (start_new_block || stmt_starts_bb_p (stmt, prev_stmt)) | |
372 | { | |
373 | if (!first_stmt_of_list) | |
374 | stmt_list = tsi_split_statement_list_before (&i); | |
375 | bb = create_basic_block (stmt_list, NULL, bb); | |
376 | start_new_block = false; | |
377 | } | |
378 | ||
379 | /* Now add STMT to BB and create the subgraphs for special statement | |
380 | codes. */ | |
381 | set_bb_for_stmt (stmt, bb); | |
382 | ||
383 | if (computed_goto_p (stmt)) | |
384 | found_computed_goto = true; | |
385 | ||
386 | /* If STMT is a basic block terminator, set START_NEW_BLOCK for the | |
387 | next iteration. */ | |
388 | if (stmt_ends_bb_p (stmt)) | |
389 | start_new_block = true; | |
390 | ||
391 | tsi_next (&i); | |
392 | first_stmt_of_list = false; | |
393 | } | |
394 | } | |
395 | ||
396 | ||
397 | /* Create and return a new empty basic block after bb AFTER. */ | |
398 | ||
399 | static basic_block | |
400 | create_bb (void *h, void *e, basic_block after) | |
401 | { | |
402 | basic_block bb; | |
403 | ||
1e128c5f | 404 | gcc_assert (!e); |
6de9cd9a | 405 | |
27fd69fa KH |
406 | /* Create and initialize a new basic block. Since alloc_block uses |
407 | ggc_alloc_cleared to allocate a basic block, we do not have to | |
408 | clear the newly allocated basic block here. */ | |
6de9cd9a | 409 | bb = alloc_block (); |
6de9cd9a DN |
410 | |
411 | bb->index = last_basic_block; | |
412 | bb->flags = BB_NEW; | |
413 | bb->stmt_list = h ? h : alloc_stmt_list (); | |
414 | ||
415 | /* Add the new block to the linked list of blocks. */ | |
416 | link_block (bb, after); | |
417 | ||
418 | /* Grow the basic block array if needed. */ | |
419 | if ((size_t) last_basic_block == VARRAY_SIZE (basic_block_info)) | |
420 | { | |
421 | size_t new_size = last_basic_block + (last_basic_block + 3) / 4; | |
422 | VARRAY_GROW (basic_block_info, new_size); | |
423 | } | |
424 | ||
425 | /* Add the newly created block to the array. */ | |
426 | BASIC_BLOCK (last_basic_block) = bb; | |
427 | ||
428 | create_block_annotation (bb); | |
429 | ||
430 | n_basic_blocks++; | |
431 | last_basic_block++; | |
432 | ||
433 | initialize_bb_rbi (bb); | |
434 | return bb; | |
435 | } | |
436 | ||
437 | ||
438 | /*--------------------------------------------------------------------------- | |
439 | Edge creation | |
440 | ---------------------------------------------------------------------------*/ | |
441 | ||
442 | /* Join all the blocks in the flowgraph. */ | |
443 | ||
444 | static void | |
445 | make_edges (void) | |
446 | { | |
447 | basic_block bb; | |
6de9cd9a DN |
448 | |
449 | /* Create an edge from entry to the first block with executable | |
450 | statements in it. */ | |
451 | make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU); | |
452 | ||
453 | /* Traverse basic block array placing edges. */ | |
454 | FOR_EACH_BB (bb) | |
455 | { | |
456 | tree first = first_stmt (bb); | |
457 | tree last = last_stmt (bb); | |
458 | ||
459 | if (first) | |
460 | { | |
461 | /* Edges for statements that always alter flow control. */ | |
462 | if (is_ctrl_stmt (last)) | |
463 | make_ctrl_stmt_edges (bb); | |
464 | ||
465 | /* Edges for statements that sometimes alter flow control. */ | |
466 | if (is_ctrl_altering_stmt (last)) | |
467 | make_exit_edges (bb); | |
468 | } | |
469 | ||
470 | /* Finally, if no edges were created above, this is a regular | |
471 | basic block that only needs a fallthru edge. */ | |
628f6a4e | 472 | if (EDGE_COUNT (bb->succs) == 0) |
6de9cd9a DN |
473 | make_edge (bb, bb->next_bb, EDGE_FALLTHRU); |
474 | } | |
475 | ||
6de9cd9a DN |
476 | /* We do not care about fake edges, so remove any that the CFG |
477 | builder inserted for completeness. */ | |
6809cbf9 | 478 | remove_fake_exit_edges (); |
6de9cd9a | 479 | |
6de9cd9a DN |
480 | /* Clean up the graph and warn for unreachable code. */ |
481 | cleanup_tree_cfg (); | |
482 | } | |
483 | ||
484 | ||
485 | /* Create edges for control statement at basic block BB. */ | |
486 | ||
487 | static void | |
488 | make_ctrl_stmt_edges (basic_block bb) | |
489 | { | |
490 | tree last = last_stmt (bb); | |
6de9cd9a | 491 | |
1e128c5f | 492 | gcc_assert (last); |
6de9cd9a DN |
493 | switch (TREE_CODE (last)) |
494 | { | |
495 | case GOTO_EXPR: | |
496 | make_goto_expr_edges (bb); | |
497 | break; | |
498 | ||
499 | case RETURN_EXPR: | |
500 | make_edge (bb, EXIT_BLOCK_PTR, 0); | |
501 | break; | |
502 | ||
503 | case COND_EXPR: | |
504 | make_cond_expr_edges (bb); | |
505 | break; | |
506 | ||
507 | case SWITCH_EXPR: | |
508 | make_switch_expr_edges (bb); | |
509 | break; | |
510 | ||
511 | case RESX_EXPR: | |
512 | make_eh_edges (last); | |
513 | /* Yet another NORETURN hack. */ | |
628f6a4e | 514 | if (EDGE_COUNT (bb->succs) == 0) |
6de9cd9a DN |
515 | make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE); |
516 | break; | |
517 | ||
518 | default: | |
1e128c5f | 519 | gcc_unreachable (); |
6de9cd9a DN |
520 | } |
521 | } | |
522 | ||
523 | ||
524 | /* Create exit edges for statements in block BB that alter the flow of | |
525 | control. Statements that alter the control flow are 'goto', 'return' | |
526 | and calls to non-returning functions. */ | |
527 | ||
528 | static void | |
529 | make_exit_edges (basic_block bb) | |
530 | { | |
cd709752 | 531 | tree last = last_stmt (bb), op; |
6de9cd9a | 532 | |
1e128c5f | 533 | gcc_assert (last); |
6de9cd9a DN |
534 | switch (TREE_CODE (last)) |
535 | { | |
536 | case CALL_EXPR: | |
537 | /* If this function receives a nonlocal goto, then we need to | |
538 | make edges from this call site to all the nonlocal goto | |
539 | handlers. */ | |
540 | if (TREE_SIDE_EFFECTS (last) | |
541 | && current_function_has_nonlocal_label) | |
542 | make_goto_expr_edges (bb); | |
543 | ||
544 | /* If this statement has reachable exception handlers, then | |
545 | create abnormal edges to them. */ | |
546 | make_eh_edges (last); | |
547 | ||
548 | /* Some calls are known not to return. For such calls we create | |
549 | a fake edge. | |
550 | ||
551 | We really need to revamp how we build edges so that it's not | |
552 | such a bloody pain to avoid creating edges for this case since | |
553 | all we do is remove these edges when we're done building the | |
554 | CFG. */ | |
6e14af16 | 555 | if (call_expr_flags (last) & ECF_NORETURN) |
6de9cd9a DN |
556 | { |
557 | make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE); | |
558 | return; | |
559 | } | |
560 | ||
561 | /* Don't forget the fall-thru edge. */ | |
562 | make_edge (bb, bb->next_bb, EDGE_FALLTHRU); | |
563 | break; | |
564 | ||
565 | case MODIFY_EXPR: | |
566 | /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the CALL_EXPR | |
567 | may have an abnormal edge. Search the RHS for this case and | |
568 | create any required edges. */ | |
cd709752 RH |
569 | op = get_call_expr_in (last); |
570 | if (op && TREE_SIDE_EFFECTS (op) | |
6de9cd9a DN |
571 | && current_function_has_nonlocal_label) |
572 | make_goto_expr_edges (bb); | |
573 | ||
574 | make_eh_edges (last); | |
575 | make_edge (bb, bb->next_bb, EDGE_FALLTHRU); | |
576 | break; | |
577 | ||
578 | default: | |
1e128c5f | 579 | gcc_unreachable (); |
6de9cd9a DN |
580 | } |
581 | } | |
582 | ||
583 | ||
584 | /* Create the edges for a COND_EXPR starting at block BB. | |
585 | At this point, both clauses must contain only simple gotos. */ | |
586 | ||
587 | static void | |
588 | make_cond_expr_edges (basic_block bb) | |
589 | { | |
590 | tree entry = last_stmt (bb); | |
591 | basic_block then_bb, else_bb; | |
592 | tree then_label, else_label; | |
593 | ||
1e128c5f GB |
594 | gcc_assert (entry); |
595 | gcc_assert (TREE_CODE (entry) == COND_EXPR); | |
6de9cd9a DN |
596 | |
597 | /* Entry basic blocks for each component. */ | |
598 | then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry)); | |
599 | else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry)); | |
600 | then_bb = label_to_block (then_label); | |
601 | else_bb = label_to_block (else_label); | |
602 | ||
603 | make_edge (bb, then_bb, EDGE_TRUE_VALUE); | |
604 | make_edge (bb, else_bb, EDGE_FALSE_VALUE); | |
605 | } | |
606 | ||
d6be0d7f | 607 | /* Hashing routine for EDGE_TO_CASES. */ |
92b6dff3 JL |
608 | |
609 | static hashval_t | |
d6be0d7f | 610 | edge_to_cases_hash (const void *p) |
92b6dff3 | 611 | { |
d6be0d7f | 612 | edge e = ((struct edge_to_cases_elt *)p)->e; |
92b6dff3 JL |
613 | |
614 | /* Hash on the edge itself (which is a pointer). */ | |
615 | return htab_hash_pointer (e); | |
616 | } | |
617 | ||
d6be0d7f | 618 | /* Equality routine for EDGE_TO_CASES, edges are unique, so testing |
92b6dff3 JL |
619 | for equality is just a pointer comparison. */ |
620 | ||
621 | static int | |
d6be0d7f | 622 | edge_to_cases_eq (const void *p1, const void *p2) |
92b6dff3 | 623 | { |
d6be0d7f JL |
624 | edge e1 = ((struct edge_to_cases_elt *)p1)->e; |
625 | edge e2 = ((struct edge_to_cases_elt *)p2)->e; | |
92b6dff3 JL |
626 | |
627 | return e1 == e2; | |
628 | } | |
629 | ||
d6be0d7f JL |
630 | /* Called for each element in the hash table (P) as we delete the |
631 | edge to cases hash table. | |
632 | ||
633 | Clear all the TREE_CHAINs to prevent problems with copying of | |
634 | SWITCH_EXPRs and structure sharing rules, then free the hash table | |
635 | element. */ | |
636 | ||
637 | static void | |
638 | edge_to_cases_cleanup (void *p) | |
639 | { | |
640 | struct edge_to_cases_elt *elt = p; | |
641 | tree t, next; | |
642 | ||
643 | for (t = elt->case_labels; t; t = next) | |
644 | { | |
645 | next = TREE_CHAIN (t); | |
646 | TREE_CHAIN (t) = NULL; | |
647 | } | |
648 | free (p); | |
649 | } | |
650 | ||
651 | /* Start recording information mapping edges to case labels. */ | |
652 | ||
653 | static void | |
654 | start_recording_case_labels (void) | |
655 | { | |
656 | gcc_assert (edge_to_cases == NULL); | |
657 | ||
658 | edge_to_cases = htab_create (37, | |
659 | edge_to_cases_hash, | |
660 | edge_to_cases_eq, | |
661 | edge_to_cases_cleanup); | |
662 | } | |
663 | ||
664 | /* Return nonzero if we are recording information for case labels. */ | |
665 | ||
666 | static bool | |
667 | recording_case_labels_p (void) | |
668 | { | |
669 | return (edge_to_cases != NULL); | |
670 | } | |
671 | ||
672 | /* Stop recording information mapping edges to case labels and | |
673 | remove any information we have recorded. */ | |
674 | static void | |
675 | end_recording_case_labels (void) | |
676 | { | |
677 | htab_delete (edge_to_cases); | |
678 | edge_to_cases = NULL; | |
679 | } | |
680 | ||
92b6dff3 JL |
681 | /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */ |
682 | ||
683 | static void | |
684 | record_switch_edge (edge e, tree case_label) | |
685 | { | |
d6be0d7f | 686 | struct edge_to_cases_elt *elt; |
92b6dff3 JL |
687 | void **slot; |
688 | ||
689 | /* Build a hash table element so we can see if E is already | |
690 | in the table. */ | |
d6be0d7f | 691 | elt = xmalloc (sizeof (struct edge_to_cases_elt)); |
92b6dff3 | 692 | elt->e = e; |
d6be0d7f | 693 | elt->case_labels = case_label; |
92b6dff3 | 694 | |
d6be0d7f | 695 | slot = htab_find_slot (edge_to_cases, elt, INSERT); |
92b6dff3 JL |
696 | |
697 | if (*slot == NULL) | |
698 | { | |
699 | /* E was not in the hash table. Install E into the hash table. */ | |
700 | *slot = (void *)elt; | |
701 | } | |
702 | else | |
703 | { | |
704 | /* E was already in the hash table. Free ELT as we do not need it | |
705 | anymore. */ | |
706 | free (elt); | |
707 | ||
708 | /* Get the entry stored in the hash table. */ | |
d6be0d7f | 709 | elt = (struct edge_to_cases_elt *) *slot; |
92b6dff3 | 710 | |
d6be0d7f JL |
711 | /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */ |
712 | TREE_CHAIN (case_label) = elt->case_labels; | |
713 | elt->case_labels = case_label; | |
92b6dff3 JL |
714 | } |
715 | } | |
716 | ||
d6be0d7f JL |
717 | /* If we are inside a {start,end}_recording_cases block, then return |
718 | a chain of CASE_LABEL_EXPRs from T which reference E. | |
719 | ||
720 | Otherwise return NULL. */ | |
92b6dff3 JL |
721 | |
722 | static tree | |
d6be0d7f | 723 | get_cases_for_edge (edge e, tree t) |
92b6dff3 | 724 | { |
d6be0d7f | 725 | struct edge_to_cases_elt elt, *elt_p; |
92b6dff3 | 726 | void **slot; |
d6be0d7f JL |
727 | size_t i, n; |
728 | tree vec; | |
92b6dff3 | 729 | |
d6be0d7f JL |
730 | /* If we are not recording cases, then we do not have CASE_LABEL_EXPR |
731 | chains available. Return NULL so the caller can detect this case. */ | |
732 | if (!recording_case_labels_p ()) | |
733 | return NULL; | |
734 | ||
735 | restart: | |
92b6dff3 | 736 | elt.e = e; |
d6be0d7f JL |
737 | elt.case_labels = NULL; |
738 | slot = htab_find_slot (edge_to_cases, &elt, NO_INSERT); | |
92b6dff3 JL |
739 | |
740 | if (slot) | |
741 | { | |
d6be0d7f JL |
742 | elt_p = (struct edge_to_cases_elt *)*slot; |
743 | return elt_p->case_labels; | |
92b6dff3 JL |
744 | } |
745 | ||
d6be0d7f JL |
746 | /* If we did not find E in the hash table, then this must be the first |
747 | time we have been queried for information about E & T. Add all the | |
748 | elements from T to the hash table then perform the query again. */ | |
92b6dff3 | 749 | |
d6be0d7f | 750 | vec = SWITCH_LABELS (t); |
92b6dff3 | 751 | n = TREE_VEC_LENGTH (vec); |
92b6dff3 JL |
752 | for (i = 0; i < n; i++) |
753 | { | |
d6be0d7f JL |
754 | tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i)); |
755 | basic_block label_bb = label_to_block (lab); | |
756 | record_switch_edge (find_edge (e->src, label_bb), TREE_VEC_ELT (vec, i)); | |
92b6dff3 | 757 | } |
d6be0d7f | 758 | goto restart; |
92b6dff3 | 759 | } |
6de9cd9a DN |
760 | |
761 | /* Create the edges for a SWITCH_EXPR starting at block BB. | |
762 | At this point, the switch body has been lowered and the | |
763 | SWITCH_LABELS filled in, so this is in effect a multi-way branch. */ | |
764 | ||
765 | static void | |
766 | make_switch_expr_edges (basic_block bb) | |
767 | { | |
768 | tree entry = last_stmt (bb); | |
769 | size_t i, n; | |
770 | tree vec; | |
771 | ||
772 | vec = SWITCH_LABELS (entry); | |
773 | n = TREE_VEC_LENGTH (vec); | |
774 | ||
775 | for (i = 0; i < n; ++i) | |
776 | { | |
777 | tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i)); | |
778 | basic_block label_bb = label_to_block (lab); | |
d6be0d7f | 779 | make_edge (bb, label_bb, 0); |
6de9cd9a DN |
780 | } |
781 | } | |
782 | ||
783 | ||
784 | /* Return the basic block holding label DEST. */ | |
785 | ||
786 | basic_block | |
787 | label_to_block (tree dest) | |
788 | { | |
242229bb JH |
789 | int uid = LABEL_DECL_UID (dest); |
790 | ||
f0b698c1 KH |
791 | /* We would die hard when faced by an undefined label. Emit a label to |
792 | the very first basic block. This will hopefully make even the dataflow | |
242229bb JH |
793 | and undefined variable warnings quite right. */ |
794 | if ((errorcount || sorrycount) && uid < 0) | |
795 | { | |
796 | block_stmt_iterator bsi = bsi_start (BASIC_BLOCK (0)); | |
797 | tree stmt; | |
798 | ||
799 | stmt = build1 (LABEL_EXPR, void_type_node, dest); | |
800 | bsi_insert_before (&bsi, stmt, BSI_NEW_STMT); | |
801 | uid = LABEL_DECL_UID (dest); | |
802 | } | |
803 | return VARRAY_BB (label_to_block_map, uid); | |
6de9cd9a DN |
804 | } |
805 | ||
806 | ||
807 | /* Create edges for a goto statement at block BB. */ | |
808 | ||
809 | static void | |
810 | make_goto_expr_edges (basic_block bb) | |
811 | { | |
812 | tree goto_t, dest; | |
813 | basic_block target_bb; | |
814 | int for_call; | |
815 | block_stmt_iterator last = bsi_last (bb); | |
816 | ||
817 | goto_t = bsi_stmt (last); | |
818 | ||
819 | /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR, | |
820 | CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting | |
821 | from a nonlocal goto. */ | |
822 | if (TREE_CODE (goto_t) != GOTO_EXPR) | |
823 | { | |
824 | dest = error_mark_node; | |
825 | for_call = 1; | |
826 | } | |
827 | else | |
828 | { | |
829 | dest = GOTO_DESTINATION (goto_t); | |
830 | for_call = 0; | |
831 | ||
832 | /* A GOTO to a local label creates normal edges. */ | |
833 | if (simple_goto_p (goto_t)) | |
834 | { | |
62b857ea | 835 | edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU); |
9506ac2b PB |
836 | #ifdef USE_MAPPED_LOCATION |
837 | e->goto_locus = EXPR_LOCATION (goto_t); | |
838 | #else | |
62b857ea | 839 | e->goto_locus = EXPR_LOCUS (goto_t); |
9506ac2b | 840 | #endif |
6de9cd9a DN |
841 | bsi_remove (&last); |
842 | return; | |
843 | } | |
844 | ||
9cf737f8 | 845 | /* Nothing more to do for nonlocal gotos. */ |
6de9cd9a DN |
846 | if (TREE_CODE (dest) == LABEL_DECL) |
847 | return; | |
848 | ||
849 | /* Computed gotos remain. */ | |
850 | } | |
851 | ||
852 | /* Look for the block starting with the destination label. In the | |
853 | case of a computed goto, make an edge to any label block we find | |
854 | in the CFG. */ | |
855 | FOR_EACH_BB (target_bb) | |
856 | { | |
857 | block_stmt_iterator bsi; | |
858 | ||
859 | for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
860 | { | |
861 | tree target = bsi_stmt (bsi); | |
862 | ||
863 | if (TREE_CODE (target) != LABEL_EXPR) | |
864 | break; | |
865 | ||
866 | if ( | |
867 | /* Computed GOTOs. Make an edge to every label block that has | |
868 | been marked as a potential target for a computed goto. */ | |
869 | (FORCED_LABEL (LABEL_EXPR_LABEL (target)) && for_call == 0) | |
870 | /* Nonlocal GOTO target. Make an edge to every label block | |
871 | that has been marked as a potential target for a nonlocal | |
872 | goto. */ | |
873 | || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target)) && for_call == 1)) | |
874 | { | |
875 | make_edge (bb, target_bb, EDGE_ABNORMAL); | |
876 | break; | |
877 | } | |
878 | } | |
879 | } | |
880 | ||
881 | /* Degenerate case of computed goto with no labels. */ | |
628f6a4e | 882 | if (!for_call && EDGE_COUNT (bb->succs) == 0) |
6de9cd9a DN |
883 | make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE); |
884 | } | |
885 | ||
886 | ||
887 | /*--------------------------------------------------------------------------- | |
888 | Flowgraph analysis | |
889 | ---------------------------------------------------------------------------*/ | |
890 | ||
891 | /* Remove unreachable blocks and other miscellaneous clean up work. */ | |
892 | ||
56b043c8 | 893 | bool |
6de9cd9a DN |
894 | cleanup_tree_cfg (void) |
895 | { | |
56b043c8 | 896 | bool retval = false; |
6de9cd9a DN |
897 | |
898 | timevar_push (TV_TREE_CLEANUP_CFG); | |
899 | ||
8f28be81 | 900 | retval = cleanup_control_flow (); |
26d4492f | 901 | retval |= delete_unreachable_blocks (); |
d6be0d7f JL |
902 | |
903 | /* thread_jumps can redirect edges out of SWITCH_EXPRs, which can get | |
904 | expensive. So we want to enable recording of edge to CASE_LABEL_EXPR | |
905 | mappings around the call to thread_jumps. */ | |
906 | start_recording_case_labels (); | |
ab51c2f0 | 907 | retval |= thread_jumps (); |
d6be0d7f | 908 | end_recording_case_labels (); |
6de9cd9a | 909 | |
8f28be81 KH |
910 | #ifdef ENABLE_CHECKING |
911 | if (retval) | |
26d4492f KH |
912 | { |
913 | gcc_assert (!cleanup_control_flow ()); | |
914 | gcc_assert (!delete_unreachable_blocks ()); | |
ab51c2f0 | 915 | gcc_assert (!thread_jumps ()); |
26d4492f | 916 | } |
8f28be81 KH |
917 | #endif |
918 | ||
6de9cd9a DN |
919 | /* Merging the blocks creates no new opportunities for the other |
920 | optimizations, so do it here. */ | |
086aa12e | 921 | retval |= merge_seq_blocks (); |
6de9cd9a DN |
922 | |
923 | compact_blocks (); | |
924 | ||
925 | #ifdef ENABLE_CHECKING | |
926 | verify_flow_info (); | |
927 | #endif | |
928 | timevar_pop (TV_TREE_CLEANUP_CFG); | |
56b043c8 | 929 | return retval; |
6de9cd9a DN |
930 | } |
931 | ||
932 | ||
f698d217 SB |
933 | /* Cleanup useless labels in basic blocks. This is something we wish |
934 | to do early because it allows us to group case labels before creating | |
935 | the edges for the CFG, and it speeds up block statement iterators in | |
936 | all passes later on. | |
937 | We only run this pass once, running it more than once is probably not | |
938 | profitable. */ | |
939 | ||
940 | /* A map from basic block index to the leading label of that block. */ | |
941 | static tree *label_for_bb; | |
942 | ||
943 | /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */ | |
944 | static void | |
945 | update_eh_label (struct eh_region *region) | |
946 | { | |
947 | tree old_label = get_eh_region_tree_label (region); | |
948 | if (old_label) | |
949 | { | |
165b54c3 SB |
950 | tree new_label; |
951 | basic_block bb = label_to_block (old_label); | |
952 | ||
953 | /* ??? After optimizing, there may be EH regions with labels | |
954 | that have already been removed from the function body, so | |
955 | there is no basic block for them. */ | |
956 | if (! bb) | |
957 | return; | |
958 | ||
959 | new_label = label_for_bb[bb->index]; | |
f698d217 SB |
960 | set_eh_region_tree_label (region, new_label); |
961 | } | |
962 | } | |
963 | ||
242229bb JH |
964 | /* Given LABEL return the first label in the same basic block. */ |
965 | static tree | |
966 | main_block_label (tree label) | |
967 | { | |
968 | basic_block bb = label_to_block (label); | |
969 | ||
970 | /* label_to_block possibly inserted undefined label into the chain. */ | |
971 | if (!label_for_bb[bb->index]) | |
972 | label_for_bb[bb->index] = label; | |
973 | return label_for_bb[bb->index]; | |
974 | } | |
975 | ||
b986ebf3 | 976 | /* Cleanup redundant labels. This is a three-step process: |
f698d217 SB |
977 | 1) Find the leading label for each block. |
978 | 2) Redirect all references to labels to the leading labels. | |
979 | 3) Cleanup all useless labels. */ | |
6de9cd9a | 980 | |
165b54c3 | 981 | void |
6de9cd9a DN |
982 | cleanup_dead_labels (void) |
983 | { | |
984 | basic_block bb; | |
f698d217 | 985 | label_for_bb = xcalloc (last_basic_block, sizeof (tree)); |
6de9cd9a DN |
986 | |
987 | /* Find a suitable label for each block. We use the first user-defined | |
f0b698c1 | 988 | label if there is one, or otherwise just the first label we see. */ |
6de9cd9a DN |
989 | FOR_EACH_BB (bb) |
990 | { | |
991 | block_stmt_iterator i; | |
992 | ||
993 | for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i)) | |
994 | { | |
995 | tree label, stmt = bsi_stmt (i); | |
996 | ||
997 | if (TREE_CODE (stmt) != LABEL_EXPR) | |
998 | break; | |
999 | ||
1000 | label = LABEL_EXPR_LABEL (stmt); | |
1001 | ||
1002 | /* If we have not yet seen a label for the current block, | |
1003 | remember this one and see if there are more labels. */ | |
1004 | if (! label_for_bb[bb->index]) | |
1005 | { | |
1006 | label_for_bb[bb->index] = label; | |
1007 | continue; | |
1008 | } | |
1009 | ||
1010 | /* If we did see a label for the current block already, but it | |
1011 | is an artificially created label, replace it if the current | |
1012 | label is a user defined label. */ | |
1013 | if (! DECL_ARTIFICIAL (label) | |
1014 | && DECL_ARTIFICIAL (label_for_bb[bb->index])) | |
1015 | { | |
1016 | label_for_bb[bb->index] = label; | |
1017 | break; | |
1018 | } | |
1019 | } | |
1020 | } | |
1021 | ||
f698d217 SB |
1022 | /* Now redirect all jumps/branches to the selected label. |
1023 | First do so for each block ending in a control statement. */ | |
6de9cd9a DN |
1024 | FOR_EACH_BB (bb) |
1025 | { | |
1026 | tree stmt = last_stmt (bb); | |
1027 | if (!stmt) | |
1028 | continue; | |
1029 | ||
1030 | switch (TREE_CODE (stmt)) | |
1031 | { | |
1032 | case COND_EXPR: | |
1033 | { | |
1034 | tree true_branch, false_branch; | |
6de9cd9a DN |
1035 | |
1036 | true_branch = COND_EXPR_THEN (stmt); | |
1037 | false_branch = COND_EXPR_ELSE (stmt); | |
6de9cd9a | 1038 | |
242229bb JH |
1039 | GOTO_DESTINATION (true_branch) |
1040 | = main_block_label (GOTO_DESTINATION (true_branch)); | |
1041 | GOTO_DESTINATION (false_branch) | |
1042 | = main_block_label (GOTO_DESTINATION (false_branch)); | |
6de9cd9a DN |
1043 | |
1044 | break; | |
1045 | } | |
1046 | ||
1047 | case SWITCH_EXPR: | |
1048 | { | |
1049 | size_t i; | |
1050 | tree vec = SWITCH_LABELS (stmt); | |
1051 | size_t n = TREE_VEC_LENGTH (vec); | |
1052 | ||
1053 | /* Replace all destination labels. */ | |
1054 | for (i = 0; i < n; ++i) | |
92b6dff3 JL |
1055 | { |
1056 | tree elt = TREE_VEC_ELT (vec, i); | |
1057 | tree label = main_block_label (CASE_LABEL (elt)); | |
d6be0d7f | 1058 | CASE_LABEL (elt) = label; |
92b6dff3 | 1059 | } |
6de9cd9a DN |
1060 | break; |
1061 | } | |
1062 | ||
f667741c SB |
1063 | /* We have to handle GOTO_EXPRs until they're removed, and we don't |
1064 | remove them until after we've created the CFG edges. */ | |
1065 | case GOTO_EXPR: | |
242229bb JH |
1066 | if (! computed_goto_p (stmt)) |
1067 | { | |
1068 | GOTO_DESTINATION (stmt) | |
1069 | = main_block_label (GOTO_DESTINATION (stmt)); | |
1070 | break; | |
1071 | } | |
f667741c | 1072 | |
6de9cd9a DN |
1073 | default: |
1074 | break; | |
1075 | } | |
1076 | } | |
1077 | ||
f698d217 SB |
1078 | for_each_eh_region (update_eh_label); |
1079 | ||
6de9cd9a DN |
1080 | /* Finally, purge dead labels. All user-defined labels and labels that |
1081 | can be the target of non-local gotos are preserved. */ | |
1082 | FOR_EACH_BB (bb) | |
1083 | { | |
1084 | block_stmt_iterator i; | |
1085 | tree label_for_this_bb = label_for_bb[bb->index]; | |
1086 | ||
1087 | if (! label_for_this_bb) | |
1088 | continue; | |
1089 | ||
1090 | for (i = bsi_start (bb); !bsi_end_p (i); ) | |
1091 | { | |
1092 | tree label, stmt = bsi_stmt (i); | |
1093 | ||
1094 | if (TREE_CODE (stmt) != LABEL_EXPR) | |
1095 | break; | |
1096 | ||
1097 | label = LABEL_EXPR_LABEL (stmt); | |
1098 | ||
1099 | if (label == label_for_this_bb | |
1100 | || ! DECL_ARTIFICIAL (label) | |
1101 | || DECL_NONLOCAL (label)) | |
1102 | bsi_next (&i); | |
1103 | else | |
1104 | bsi_remove (&i); | |
1105 | } | |
1106 | } | |
1107 | ||
1108 | free (label_for_bb); | |
1109 | } | |
1110 | ||
f667741c SB |
1111 | /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE), |
1112 | and scan the sorted vector of cases. Combine the ones jumping to the | |
1113 | same label. | |
1114 | Eg. three separate entries 1: 2: 3: become one entry 1..3: */ | |
1115 | ||
165b54c3 | 1116 | void |
f667741c SB |
1117 | group_case_labels (void) |
1118 | { | |
1119 | basic_block bb; | |
1120 | ||
1121 | FOR_EACH_BB (bb) | |
1122 | { | |
1123 | tree stmt = last_stmt (bb); | |
1124 | if (stmt && TREE_CODE (stmt) == SWITCH_EXPR) | |
1125 | { | |
1126 | tree labels = SWITCH_LABELS (stmt); | |
1127 | int old_size = TREE_VEC_LENGTH (labels); | |
1128 | int i, j, new_size = old_size; | |
29c4d22b AP |
1129 | tree default_case = TREE_VEC_ELT (labels, old_size - 1); |
1130 | tree default_label; | |
1131 | ||
66efeafc | 1132 | /* The default label is always the last case in a switch |
29c4d22b AP |
1133 | statement after gimplification. */ |
1134 | default_label = CASE_LABEL (default_case); | |
f667741c SB |
1135 | |
1136 | /* Look for possible opportunities to merge cases. | |
1137 | Ignore the last element of the label vector because it | |
1138 | must be the default case. */ | |
1139 | i = 0; | |
d717e500 | 1140 | while (i < old_size - 1) |
f667741c SB |
1141 | { |
1142 | tree base_case, base_label, base_high, type; | |
1143 | base_case = TREE_VEC_ELT (labels, i); | |
1144 | ||
1e128c5f | 1145 | gcc_assert (base_case); |
f667741c | 1146 | base_label = CASE_LABEL (base_case); |
31e9eea2 SB |
1147 | |
1148 | /* Discard cases that have the same destination as the | |
1149 | default case. */ | |
1150 | if (base_label == default_label) | |
1151 | { | |
1152 | TREE_VEC_ELT (labels, i) = NULL_TREE; | |
1153 | i++; | |
29c4d22b | 1154 | new_size--; |
31e9eea2 SB |
1155 | continue; |
1156 | } | |
1157 | ||
1158 | type = TREE_TYPE (CASE_LOW (base_case)); | |
f667741c SB |
1159 | base_high = CASE_HIGH (base_case) ? |
1160 | CASE_HIGH (base_case) : CASE_LOW (base_case); | |
d717e500 | 1161 | i++; |
f667741c SB |
1162 | /* Try to merge case labels. Break out when we reach the end |
1163 | of the label vector or when we cannot merge the next case | |
1164 | label with the current one. */ | |
d717e500 | 1165 | while (i < old_size - 1) |
f667741c | 1166 | { |
d717e500 | 1167 | tree merge_case = TREE_VEC_ELT (labels, i); |
f667741c SB |
1168 | tree merge_label = CASE_LABEL (merge_case); |
1169 | tree t = int_const_binop (PLUS_EXPR, base_high, | |
1170 | integer_one_node, 1); | |
1171 | ||
1172 | /* Merge the cases if they jump to the same place, | |
1173 | and their ranges are consecutive. */ | |
1174 | if (merge_label == base_label | |
1175 | && tree_int_cst_equal (CASE_LOW (merge_case), t)) | |
1176 | { | |
1177 | base_high = CASE_HIGH (merge_case) ? | |
1178 | CASE_HIGH (merge_case) : CASE_LOW (merge_case); | |
1179 | CASE_HIGH (base_case) = base_high; | |
1180 | TREE_VEC_ELT (labels, i) = NULL_TREE; | |
1181 | new_size--; | |
d717e500 | 1182 | i++; |
f667741c SB |
1183 | } |
1184 | else | |
1185 | break; | |
1186 | } | |
1187 | } | |
1188 | ||
1189 | /* Compress the case labels in the label vector, and adjust the | |
1190 | length of the vector. */ | |
1191 | for (i = 0, j = 0; i < new_size; i++) | |
1192 | { | |
1193 | while (! TREE_VEC_ELT (labels, j)) | |
1194 | j++; | |
1195 | TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++); | |
1196 | } | |
1197 | TREE_VEC_LENGTH (labels) = new_size; | |
1198 | } | |
1199 | } | |
1200 | } | |
6de9cd9a DN |
1201 | |
1202 | /* Checks whether we can merge block B into block A. */ | |
1203 | ||
1204 | static bool | |
1205 | tree_can_merge_blocks_p (basic_block a, basic_block b) | |
1206 | { | |
1207 | tree stmt; | |
1208 | block_stmt_iterator bsi; | |
1209 | ||
628f6a4e | 1210 | if (EDGE_COUNT (a->succs) != 1) |
6de9cd9a DN |
1211 | return false; |
1212 | ||
628f6a4e | 1213 | if (EDGE_SUCC (a, 0)->flags & EDGE_ABNORMAL) |
6de9cd9a DN |
1214 | return false; |
1215 | ||
628f6a4e | 1216 | if (EDGE_SUCC (a, 0)->dest != b) |
6de9cd9a DN |
1217 | return false; |
1218 | ||
1219 | if (b == EXIT_BLOCK_PTR) | |
1220 | return false; | |
1221 | ||
628f6a4e | 1222 | if (EDGE_COUNT (b->preds) > 1) |
6de9cd9a DN |
1223 | return false; |
1224 | ||
1225 | /* If A ends by a statement causing exceptions or something similar, we | |
1226 | cannot merge the blocks. */ | |
1227 | stmt = last_stmt (a); | |
1228 | if (stmt && stmt_ends_bb_p (stmt)) | |
1229 | return false; | |
1230 | ||
1231 | /* Do not allow a block with only a non-local label to be merged. */ | |
1232 | if (stmt && TREE_CODE (stmt) == LABEL_EXPR | |
1233 | && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))) | |
1234 | return false; | |
1235 | ||
1236 | /* There may be no phi nodes at the start of b. Most of these degenerate | |
1237 | phi nodes should be cleaned up by kill_redundant_phi_nodes. */ | |
1238 | if (phi_nodes (b)) | |
1239 | return false; | |
1240 | ||
1241 | /* Do not remove user labels. */ | |
1242 | for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi)) | |
1243 | { | |
1244 | stmt = bsi_stmt (bsi); | |
1245 | if (TREE_CODE (stmt) != LABEL_EXPR) | |
1246 | break; | |
1247 | if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt))) | |
1248 | return false; | |
1249 | } | |
1250 | ||
1251 | return true; | |
1252 | } | |
1253 | ||
1254 | ||
1255 | /* Merge block B into block A. */ | |
1256 | ||
1257 | static void | |
1258 | tree_merge_blocks (basic_block a, basic_block b) | |
1259 | { | |
1260 | block_stmt_iterator bsi; | |
1261 | tree_stmt_iterator last; | |
1262 | ||
1263 | if (dump_file) | |
1264 | fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index); | |
1265 | ||
1266 | /* Ensure that B follows A. */ | |
1267 | move_block_after (b, a); | |
1268 | ||
628f6a4e | 1269 | gcc_assert (EDGE_SUCC (a, 0)->flags & EDGE_FALLTHRU); |
1e128c5f | 1270 | gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a))); |
6de9cd9a DN |
1271 | |
1272 | /* Remove labels from B and set bb_for_stmt to A for other statements. */ | |
1273 | for (bsi = bsi_start (b); !bsi_end_p (bsi);) | |
1274 | { | |
1275 | if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR) | |
1276 | bsi_remove (&bsi); | |
1277 | else | |
1278 | { | |
1279 | set_bb_for_stmt (bsi_stmt (bsi), a); | |
1280 | bsi_next (&bsi); | |
1281 | } | |
1282 | } | |
1283 | ||
1284 | /* Merge the chains. */ | |
1285 | last = tsi_last (a->stmt_list); | |
1286 | tsi_link_after (&last, b->stmt_list, TSI_NEW_STMT); | |
1287 | b->stmt_list = NULL; | |
1288 | } | |
1289 | ||
1290 | ||
1291 | /* Walk the function tree removing unnecessary statements. | |
1292 | ||
1293 | * Empty statement nodes are removed | |
1294 | ||
1295 | * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed | |
1296 | ||
1297 | * Unnecessary COND_EXPRs are removed | |
1298 | ||
1299 | * Some unnecessary BIND_EXPRs are removed | |
1300 | ||
1301 | Clearly more work could be done. The trick is doing the analysis | |
1302 | and removal fast enough to be a net improvement in compile times. | |
1303 | ||
1304 | Note that when we remove a control structure such as a COND_EXPR | |
1305 | BIND_EXPR, or TRY block, we will need to repeat this optimization pass | |
1306 | to ensure we eliminate all the useless code. */ | |
1307 | ||
1308 | struct rus_data | |
1309 | { | |
1310 | tree *last_goto; | |
1311 | bool repeat; | |
1312 | bool may_throw; | |
1313 | bool may_branch; | |
1314 | bool has_label; | |
1315 | }; | |
1316 | ||
1317 | static void remove_useless_stmts_1 (tree *, struct rus_data *); | |
1318 | ||
1319 | static bool | |
1320 | remove_useless_stmts_warn_notreached (tree stmt) | |
1321 | { | |
9506ac2b | 1322 | if (EXPR_HAS_LOCATION (stmt)) |
6de9cd9a | 1323 | { |
9506ac2b PB |
1324 | location_t loc = EXPR_LOCATION (stmt); |
1325 | warning ("%Hwill never be executed", &loc); | |
6de9cd9a DN |
1326 | return true; |
1327 | } | |
1328 | ||
1329 | switch (TREE_CODE (stmt)) | |
1330 | { | |
1331 | case STATEMENT_LIST: | |
1332 | { | |
1333 | tree_stmt_iterator i; | |
1334 | for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i)) | |
1335 | if (remove_useless_stmts_warn_notreached (tsi_stmt (i))) | |
1336 | return true; | |
1337 | } | |
1338 | break; | |
1339 | ||
1340 | case COND_EXPR: | |
1341 | if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt))) | |
1342 | return true; | |
1343 | if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt))) | |
1344 | return true; | |
1345 | if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt))) | |
1346 | return true; | |
1347 | break; | |
1348 | ||
1349 | case TRY_FINALLY_EXPR: | |
1350 | case TRY_CATCH_EXPR: | |
1351 | if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0))) | |
1352 | return true; | |
1353 | if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1))) | |
1354 | return true; | |
1355 | break; | |
1356 | ||
1357 | case CATCH_EXPR: | |
1358 | return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt)); | |
1359 | case EH_FILTER_EXPR: | |
1360 | return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt)); | |
1361 | case BIND_EXPR: | |
1362 | return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt)); | |
1363 | ||
1364 | default: | |
1365 | /* Not a live container. */ | |
1366 | break; | |
1367 | } | |
1368 | ||
1369 | return false; | |
1370 | } | |
1371 | ||
1372 | static void | |
1373 | remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data) | |
1374 | { | |
1375 | tree then_clause, else_clause, cond; | |
1376 | bool save_has_label, then_has_label, else_has_label; | |
1377 | ||
1378 | save_has_label = data->has_label; | |
1379 | data->has_label = false; | |
1380 | data->last_goto = NULL; | |
1381 | ||
1382 | remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data); | |
1383 | ||
1384 | then_has_label = data->has_label; | |
1385 | data->has_label = false; | |
1386 | data->last_goto = NULL; | |
1387 | ||
1388 | remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data); | |
1389 | ||
1390 | else_has_label = data->has_label; | |
1391 | data->has_label = save_has_label | then_has_label | else_has_label; | |
1392 | ||
6de9cd9a DN |
1393 | then_clause = COND_EXPR_THEN (*stmt_p); |
1394 | else_clause = COND_EXPR_ELSE (*stmt_p); | |
1395 | cond = COND_EXPR_COND (*stmt_p); | |
1396 | ||
1397 | /* If neither arm does anything at all, we can remove the whole IF. */ | |
1398 | if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause)) | |
1399 | { | |
1400 | *stmt_p = build_empty_stmt (); | |
1401 | data->repeat = true; | |
1402 | } | |
1403 | ||
1404 | /* If there are no reachable statements in an arm, then we can | |
1405 | zap the entire conditional. */ | |
1406 | else if (integer_nonzerop (cond) && !else_has_label) | |
1407 | { | |
1408 | if (warn_notreached) | |
1409 | remove_useless_stmts_warn_notreached (else_clause); | |
1410 | *stmt_p = then_clause; | |
1411 | data->repeat = true; | |
1412 | } | |
1413 | else if (integer_zerop (cond) && !then_has_label) | |
1414 | { | |
1415 | if (warn_notreached) | |
1416 | remove_useless_stmts_warn_notreached (then_clause); | |
1417 | *stmt_p = else_clause; | |
1418 | data->repeat = true; | |
1419 | } | |
1420 | ||
1421 | /* Check a couple of simple things on then/else with single stmts. */ | |
1422 | else | |
1423 | { | |
1424 | tree then_stmt = expr_only (then_clause); | |
1425 | tree else_stmt = expr_only (else_clause); | |
1426 | ||
1427 | /* Notice branches to a common destination. */ | |
1428 | if (then_stmt && else_stmt | |
1429 | && TREE_CODE (then_stmt) == GOTO_EXPR | |
1430 | && TREE_CODE (else_stmt) == GOTO_EXPR | |
1431 | && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt))) | |
1432 | { | |
1433 | *stmt_p = then_stmt; | |
1434 | data->repeat = true; | |
1435 | } | |
1436 | ||
1437 | /* If the THEN/ELSE clause merely assigns a value to a variable or | |
1438 | parameter which is already known to contain that value, then | |
1439 | remove the useless THEN/ELSE clause. */ | |
1440 | else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL) | |
1441 | { | |
1442 | if (else_stmt | |
1443 | && TREE_CODE (else_stmt) == MODIFY_EXPR | |
1444 | && TREE_OPERAND (else_stmt, 0) == cond | |
1445 | && integer_zerop (TREE_OPERAND (else_stmt, 1))) | |
1446 | COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list (); | |
1447 | } | |
1448 | else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR) | |
1449 | && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL | |
1450 | || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL) | |
1451 | && TREE_CONSTANT (TREE_OPERAND (cond, 1))) | |
1452 | { | |
1453 | tree stmt = (TREE_CODE (cond) == EQ_EXPR | |
1454 | ? then_stmt : else_stmt); | |
1455 | tree *location = (TREE_CODE (cond) == EQ_EXPR | |
1456 | ? &COND_EXPR_THEN (*stmt_p) | |
1457 | : &COND_EXPR_ELSE (*stmt_p)); | |
1458 | ||
1459 | if (stmt | |
1460 | && TREE_CODE (stmt) == MODIFY_EXPR | |
1461 | && TREE_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0) | |
1462 | && TREE_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1)) | |
1463 | *location = alloc_stmt_list (); | |
1464 | } | |
1465 | } | |
1466 | ||
1467 | /* Protect GOTOs in the arm of COND_EXPRs from being removed. They | |
1468 | would be re-introduced during lowering. */ | |
1469 | data->last_goto = NULL; | |
1470 | } | |
1471 | ||
1472 | ||
1473 | static void | |
1474 | remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data) | |
1475 | { | |
1476 | bool save_may_branch, save_may_throw; | |
1477 | bool this_may_branch, this_may_throw; | |
1478 | ||
1479 | /* Collect may_branch and may_throw information for the body only. */ | |
1480 | save_may_branch = data->may_branch; | |
1481 | save_may_throw = data->may_throw; | |
1482 | data->may_branch = false; | |
1483 | data->may_throw = false; | |
1484 | data->last_goto = NULL; | |
1485 | ||
1486 | remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data); | |
1487 | ||
1488 | this_may_branch = data->may_branch; | |
1489 | this_may_throw = data->may_throw; | |
1490 | data->may_branch |= save_may_branch; | |
1491 | data->may_throw |= save_may_throw; | |
1492 | data->last_goto = NULL; | |
1493 | ||
1494 | remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data); | |
1495 | ||
1496 | /* If the body is empty, then we can emit the FINALLY block without | |
1497 | the enclosing TRY_FINALLY_EXPR. */ | |
1498 | if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0))) | |
1499 | { | |
1500 | *stmt_p = TREE_OPERAND (*stmt_p, 1); | |
1501 | data->repeat = true; | |
1502 | } | |
1503 | ||
1504 | /* If the handler is empty, then we can emit the TRY block without | |
1505 | the enclosing TRY_FINALLY_EXPR. */ | |
1506 | else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1))) | |
1507 | { | |
1508 | *stmt_p = TREE_OPERAND (*stmt_p, 0); | |
1509 | data->repeat = true; | |
1510 | } | |
1511 | ||
1512 | /* If the body neither throws, nor branches, then we can safely | |
1513 | string the TRY and FINALLY blocks together. */ | |
1514 | else if (!this_may_branch && !this_may_throw) | |
1515 | { | |
1516 | tree stmt = *stmt_p; | |
1517 | *stmt_p = TREE_OPERAND (stmt, 0); | |
1518 | append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p); | |
1519 | data->repeat = true; | |
1520 | } | |
1521 | } | |
1522 | ||
1523 | ||
1524 | static void | |
1525 | remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data) | |
1526 | { | |
1527 | bool save_may_throw, this_may_throw; | |
1528 | tree_stmt_iterator i; | |
1529 | tree stmt; | |
1530 | ||
1531 | /* Collect may_throw information for the body only. */ | |
1532 | save_may_throw = data->may_throw; | |
1533 | data->may_throw = false; | |
1534 | data->last_goto = NULL; | |
1535 | ||
1536 | remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data); | |
1537 | ||
1538 | this_may_throw = data->may_throw; | |
1539 | data->may_throw = save_may_throw; | |
1540 | ||
1541 | /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */ | |
1542 | if (!this_may_throw) | |
1543 | { | |
1544 | if (warn_notreached) | |
1545 | remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1)); | |
1546 | *stmt_p = TREE_OPERAND (*stmt_p, 0); | |
1547 | data->repeat = true; | |
1548 | return; | |
1549 | } | |
1550 | ||
1551 | /* Process the catch clause specially. We may be able to tell that | |
1552 | no exceptions propagate past this point. */ | |
1553 | ||
1554 | this_may_throw = true; | |
1555 | i = tsi_start (TREE_OPERAND (*stmt_p, 1)); | |
1556 | stmt = tsi_stmt (i); | |
1557 | data->last_goto = NULL; | |
1558 | ||
1559 | switch (TREE_CODE (stmt)) | |
1560 | { | |
1561 | case CATCH_EXPR: | |
1562 | for (; !tsi_end_p (i); tsi_next (&i)) | |
1563 | { | |
1564 | stmt = tsi_stmt (i); | |
1565 | /* If we catch all exceptions, then the body does not | |
1566 | propagate exceptions past this point. */ | |
1567 | if (CATCH_TYPES (stmt) == NULL) | |
1568 | this_may_throw = false; | |
1569 | data->last_goto = NULL; | |
1570 | remove_useless_stmts_1 (&CATCH_BODY (stmt), data); | |
1571 | } | |
1572 | break; | |
1573 | ||
1574 | case EH_FILTER_EXPR: | |
1575 | if (EH_FILTER_MUST_NOT_THROW (stmt)) | |
1576 | this_may_throw = false; | |
1577 | else if (EH_FILTER_TYPES (stmt) == NULL) | |
1578 | this_may_throw = false; | |
1579 | remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data); | |
1580 | break; | |
1581 | ||
1582 | default: | |
1583 | /* Otherwise this is a cleanup. */ | |
1584 | remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data); | |
1585 | ||
1586 | /* If the cleanup is empty, then we can emit the TRY block without | |
1587 | the enclosing TRY_CATCH_EXPR. */ | |
1588 | if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1))) | |
1589 | { | |
1590 | *stmt_p = TREE_OPERAND (*stmt_p, 0); | |
1591 | data->repeat = true; | |
1592 | } | |
1593 | break; | |
1594 | } | |
1595 | data->may_throw |= this_may_throw; | |
1596 | } | |
1597 | ||
1598 | ||
1599 | static void | |
1600 | remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data) | |
1601 | { | |
1602 | tree block; | |
1603 | ||
1604 | /* First remove anything underneath the BIND_EXPR. */ | |
1605 | remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data); | |
1606 | ||
1607 | /* If the BIND_EXPR has no variables, then we can pull everything | |
1608 | up one level and remove the BIND_EXPR, unless this is the toplevel | |
1609 | BIND_EXPR for the current function or an inlined function. | |
1610 | ||
1611 | When this situation occurs we will want to apply this | |
1612 | optimization again. */ | |
1613 | block = BIND_EXPR_BLOCK (*stmt_p); | |
1614 | if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE | |
1615 | && *stmt_p != DECL_SAVED_TREE (current_function_decl) | |
1616 | && (! block | |
1617 | || ! BLOCK_ABSTRACT_ORIGIN (block) | |
1618 | || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block)) | |
1619 | != FUNCTION_DECL))) | |
1620 | { | |
1621 | *stmt_p = BIND_EXPR_BODY (*stmt_p); | |
1622 | data->repeat = true; | |
1623 | } | |
1624 | } | |
1625 | ||
1626 | ||
1627 | static void | |
1628 | remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data) | |
1629 | { | |
1630 | tree dest = GOTO_DESTINATION (*stmt_p); | |
1631 | ||
1632 | data->may_branch = true; | |
1633 | data->last_goto = NULL; | |
1634 | ||
1635 | /* Record the last goto expr, so that we can delete it if unnecessary. */ | |
1636 | if (TREE_CODE (dest) == LABEL_DECL) | |
1637 | data->last_goto = stmt_p; | |
1638 | } | |
1639 | ||
1640 | ||
1641 | static void | |
1642 | remove_useless_stmts_label (tree *stmt_p, struct rus_data *data) | |
1643 | { | |
1644 | tree label = LABEL_EXPR_LABEL (*stmt_p); | |
1645 | ||
1646 | data->has_label = true; | |
1647 | ||
1648 | /* We do want to jump across non-local label receiver code. */ | |
1649 | if (DECL_NONLOCAL (label)) | |
1650 | data->last_goto = NULL; | |
1651 | ||
1652 | else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label) | |
1653 | { | |
1654 | *data->last_goto = build_empty_stmt (); | |
1655 | data->repeat = true; | |
1656 | } | |
1657 | ||
1658 | /* ??? Add something here to delete unused labels. */ | |
1659 | } | |
1660 | ||
1661 | ||
1662 | /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its | |
1663 | decl. This allows us to eliminate redundant or useless | |
1664 | calls to "const" functions. | |
1665 | ||
1666 | Gimplifier already does the same operation, but we may notice functions | |
1667 | being const and pure once their calls has been gimplified, so we need | |
1668 | to update the flag. */ | |
1669 | ||
1670 | static void | |
1671 | update_call_expr_flags (tree call) | |
1672 | { | |
1673 | tree decl = get_callee_fndecl (call); | |
1674 | if (!decl) | |
1675 | return; | |
1676 | if (call_expr_flags (call) & (ECF_CONST | ECF_PURE)) | |
1677 | TREE_SIDE_EFFECTS (call) = 0; | |
1678 | if (TREE_NOTHROW (decl)) | |
1679 | TREE_NOTHROW (call) = 1; | |
1680 | } | |
1681 | ||
1682 | ||
1683 | /* T is CALL_EXPR. Set current_function_calls_* flags. */ | |
1684 | ||
1685 | void | |
1686 | notice_special_calls (tree t) | |
1687 | { | |
1688 | int flags = call_expr_flags (t); | |
1689 | ||
1690 | if (flags & ECF_MAY_BE_ALLOCA) | |
1691 | current_function_calls_alloca = true; | |
1692 | if (flags & ECF_RETURNS_TWICE) | |
1693 | current_function_calls_setjmp = true; | |
1694 | } | |
1695 | ||
1696 | ||
1697 | /* Clear flags set by notice_special_calls. Used by dead code removal | |
1698 | to update the flags. */ | |
1699 | ||
1700 | void | |
1701 | clear_special_calls (void) | |
1702 | { | |
1703 | current_function_calls_alloca = false; | |
1704 | current_function_calls_setjmp = false; | |
1705 | } | |
1706 | ||
1707 | ||
1708 | static void | |
1709 | remove_useless_stmts_1 (tree *tp, struct rus_data *data) | |
1710 | { | |
cd709752 | 1711 | tree t = *tp, op; |
6de9cd9a DN |
1712 | |
1713 | switch (TREE_CODE (t)) | |
1714 | { | |
1715 | case COND_EXPR: | |
1716 | remove_useless_stmts_cond (tp, data); | |
1717 | break; | |
1718 | ||
1719 | case TRY_FINALLY_EXPR: | |
1720 | remove_useless_stmts_tf (tp, data); | |
1721 | break; | |
1722 | ||
1723 | case TRY_CATCH_EXPR: | |
1724 | remove_useless_stmts_tc (tp, data); | |
1725 | break; | |
1726 | ||
1727 | case BIND_EXPR: | |
1728 | remove_useless_stmts_bind (tp, data); | |
1729 | break; | |
1730 | ||
1731 | case GOTO_EXPR: | |
1732 | remove_useless_stmts_goto (tp, data); | |
1733 | break; | |
1734 | ||
1735 | case LABEL_EXPR: | |
1736 | remove_useless_stmts_label (tp, data); | |
1737 | break; | |
1738 | ||
1739 | case RETURN_EXPR: | |
53e782e5 | 1740 | fold_stmt (tp); |
6de9cd9a DN |
1741 | data->last_goto = NULL; |
1742 | data->may_branch = true; | |
1743 | break; | |
1744 | ||
1745 | case CALL_EXPR: | |
53e782e5 | 1746 | fold_stmt (tp); |
6de9cd9a DN |
1747 | data->last_goto = NULL; |
1748 | notice_special_calls (t); | |
1749 | update_call_expr_flags (t); | |
1750 | if (tree_could_throw_p (t)) | |
1751 | data->may_throw = true; | |
1752 | break; | |
1753 | ||
1754 | case MODIFY_EXPR: | |
1755 | data->last_goto = NULL; | |
53e782e5 | 1756 | fold_stmt (tp); |
cd709752 RH |
1757 | op = get_call_expr_in (t); |
1758 | if (op) | |
6de9cd9a | 1759 | { |
cd709752 RH |
1760 | update_call_expr_flags (op); |
1761 | notice_special_calls (op); | |
6de9cd9a DN |
1762 | } |
1763 | if (tree_could_throw_p (t)) | |
1764 | data->may_throw = true; | |
1765 | break; | |
1766 | ||
1767 | case STATEMENT_LIST: | |
1768 | { | |
1769 | tree_stmt_iterator i = tsi_start (t); | |
1770 | while (!tsi_end_p (i)) | |
1771 | { | |
1772 | t = tsi_stmt (i); | |
1773 | if (IS_EMPTY_STMT (t)) | |
1774 | { | |
1775 | tsi_delink (&i); | |
1776 | continue; | |
1777 | } | |
1778 | ||
1779 | remove_useless_stmts_1 (tsi_stmt_ptr (i), data); | |
1780 | ||
1781 | t = tsi_stmt (i); | |
1782 | if (TREE_CODE (t) == STATEMENT_LIST) | |
1783 | { | |
1784 | tsi_link_before (&i, t, TSI_SAME_STMT); | |
1785 | tsi_delink (&i); | |
1786 | } | |
1787 | else | |
1788 | tsi_next (&i); | |
1789 | } | |
1790 | } | |
1791 | break; | |
8e14584d | 1792 | case ASM_EXPR: |
53e782e5 AP |
1793 | fold_stmt (tp); |
1794 | data->last_goto = NULL; | |
1795 | break; | |
6de9cd9a DN |
1796 | |
1797 | default: | |
1798 | data->last_goto = NULL; | |
1799 | break; | |
1800 | } | |
1801 | } | |
1802 | ||
1803 | static void | |
1804 | remove_useless_stmts (void) | |
1805 | { | |
1806 | struct rus_data data; | |
1807 | ||
1808 | clear_special_calls (); | |
1809 | ||
1810 | do | |
1811 | { | |
1812 | memset (&data, 0, sizeof (data)); | |
1813 | remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data); | |
1814 | } | |
1815 | while (data.repeat); | |
1816 | } | |
1817 | ||
1818 | ||
1819 | struct tree_opt_pass pass_remove_useless_stmts = | |
1820 | { | |
1821 | "useless", /* name */ | |
1822 | NULL, /* gate */ | |
1823 | remove_useless_stmts, /* execute */ | |
1824 | NULL, /* sub */ | |
1825 | NULL, /* next */ | |
1826 | 0, /* static_pass_number */ | |
1827 | 0, /* tv_id */ | |
1828 | PROP_gimple_any, /* properties_required */ | |
1829 | 0, /* properties_provided */ | |
1830 | 0, /* properties_destroyed */ | |
1831 | 0, /* todo_flags_start */ | |
9f8628ba PB |
1832 | TODO_dump_func, /* todo_flags_finish */ |
1833 | 0 /* letter */ | |
6de9cd9a DN |
1834 | }; |
1835 | ||
1836 | ||
1837 | /* Remove obviously useless statements in basic block BB. */ | |
1838 | ||
1839 | static void | |
1840 | cfg_remove_useless_stmts_bb (basic_block bb) | |
1841 | { | |
1842 | block_stmt_iterator bsi; | |
1843 | tree stmt = NULL_TREE; | |
1844 | tree cond, var = NULL_TREE, val = NULL_TREE; | |
1845 | struct var_ann_d *ann; | |
1846 | ||
1847 | /* Check whether we come here from a condition, and if so, get the | |
1848 | condition. */ | |
628f6a4e BE |
1849 | if (EDGE_COUNT (bb->preds) != 1 |
1850 | || !(EDGE_PRED (bb, 0)->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))) | |
6de9cd9a DN |
1851 | return; |
1852 | ||
628f6a4e | 1853 | cond = COND_EXPR_COND (last_stmt (EDGE_PRED (bb, 0)->src)); |
6de9cd9a DN |
1854 | |
1855 | if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL) | |
1856 | { | |
1857 | var = cond; | |
628f6a4e | 1858 | val = (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE |
6de9cd9a DN |
1859 | ? boolean_false_node : boolean_true_node); |
1860 | } | |
1861 | else if (TREE_CODE (cond) == TRUTH_NOT_EXPR | |
1862 | && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL | |
1863 | || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)) | |
1864 | { | |
1865 | var = TREE_OPERAND (cond, 0); | |
628f6a4e | 1866 | val = (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE |
6de9cd9a DN |
1867 | ? boolean_true_node : boolean_false_node); |
1868 | } | |
1869 | else | |
1870 | { | |
628f6a4e | 1871 | if (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE) |
6de9cd9a DN |
1872 | cond = invert_truthvalue (cond); |
1873 | if (TREE_CODE (cond) == EQ_EXPR | |
1874 | && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL | |
1875 | || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL) | |
1876 | && (TREE_CODE (TREE_OPERAND (cond, 1)) == VAR_DECL | |
1877 | || TREE_CODE (TREE_OPERAND (cond, 1)) == PARM_DECL | |
1878 | || TREE_CONSTANT (TREE_OPERAND (cond, 1)))) | |
1879 | { | |
1880 | var = TREE_OPERAND (cond, 0); | |
1881 | val = TREE_OPERAND (cond, 1); | |
1882 | } | |
1883 | else | |
1884 | return; | |
1885 | } | |
1886 | ||
1887 | /* Only work for normal local variables. */ | |
1888 | ann = var_ann (var); | |
1889 | if (!ann | |
1890 | || ann->may_aliases | |
1891 | || TREE_ADDRESSABLE (var)) | |
1892 | return; | |
1893 | ||
1894 | if (! TREE_CONSTANT (val)) | |
1895 | { | |
1896 | ann = var_ann (val); | |
1897 | if (!ann | |
1898 | || ann->may_aliases | |
1899 | || TREE_ADDRESSABLE (val)) | |
1900 | return; | |
1901 | } | |
1902 | ||
1903 | /* Ignore floating point variables, since comparison behaves weird for | |
1904 | them. */ | |
1905 | if (FLOAT_TYPE_P (TREE_TYPE (var))) | |
1906 | return; | |
1907 | ||
1908 | for (bsi = bsi_start (bb); !bsi_end_p (bsi);) | |
1909 | { | |
1910 | stmt = bsi_stmt (bsi); | |
1911 | ||
1912 | /* If the THEN/ELSE clause merely assigns a value to a variable/parameter | |
1913 | which is already known to contain that value, then remove the useless | |
1914 | THEN/ELSE clause. */ | |
1915 | if (TREE_CODE (stmt) == MODIFY_EXPR | |
1916 | && TREE_OPERAND (stmt, 0) == var | |
1917 | && operand_equal_p (val, TREE_OPERAND (stmt, 1), 0)) | |
1918 | { | |
1919 | bsi_remove (&bsi); | |
1920 | continue; | |
1921 | } | |
1922 | ||
631b67ce RK |
1923 | /* Invalidate the var if we encounter something that could modify it. |
1924 | Likewise for the value it was previously set to. Note that we only | |
1925 | consider values that are either a VAR_DECL or PARM_DECL so we | |
1926 | can test for conflict very simply. */ | |
6de9cd9a | 1927 | if (TREE_CODE (stmt) == ASM_EXPR |
6de9cd9a | 1928 | || (TREE_CODE (stmt) == MODIFY_EXPR |
631b67ce RK |
1929 | && (TREE_OPERAND (stmt, 0) == var |
1930 | || TREE_OPERAND (stmt, 0) == val))) | |
6de9cd9a DN |
1931 | return; |
1932 | ||
1933 | bsi_next (&bsi); | |
1934 | } | |
1935 | } | |
1936 | ||
1937 | ||
1938 | /* A CFG-aware version of remove_useless_stmts. */ | |
1939 | ||
1940 | void | |
1941 | cfg_remove_useless_stmts (void) | |
1942 | { | |
1943 | basic_block bb; | |
1944 | ||
1945 | #ifdef ENABLE_CHECKING | |
1946 | verify_flow_info (); | |
1947 | #endif | |
1948 | ||
1949 | FOR_EACH_BB (bb) | |
1950 | { | |
1951 | cfg_remove_useless_stmts_bb (bb); | |
1952 | } | |
1953 | } | |
1954 | ||
1955 | ||
1956 | /* Remove PHI nodes associated with basic block BB and all edges out of BB. */ | |
1957 | ||
1958 | static void | |
1959 | remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb) | |
1960 | { | |
1961 | tree phi; | |
1962 | ||
1963 | /* Since this block is no longer reachable, we can just delete all | |
1964 | of its PHI nodes. */ | |
1965 | phi = phi_nodes (bb); | |
1966 | while (phi) | |
1967 | { | |
17192884 | 1968 | tree next = PHI_CHAIN (phi); |
6de9cd9a DN |
1969 | remove_phi_node (phi, NULL_TREE, bb); |
1970 | phi = next; | |
1971 | } | |
1972 | ||
1973 | /* Remove edges to BB's successors. */ | |
628f6a4e | 1974 | while (EDGE_COUNT (bb->succs) > 0) |
d0d2cc21 | 1975 | remove_edge (EDGE_SUCC (bb, 0)); |
6de9cd9a DN |
1976 | } |
1977 | ||
1978 | ||
1979 | /* Remove statements of basic block BB. */ | |
1980 | ||
1981 | static void | |
1982 | remove_bb (basic_block bb) | |
1983 | { | |
1984 | block_stmt_iterator i; | |
9506ac2b | 1985 | source_locus loc = 0; |
6de9cd9a DN |
1986 | |
1987 | if (dump_file) | |
1988 | { | |
1989 | fprintf (dump_file, "Removing basic block %d\n", bb->index); | |
1990 | if (dump_flags & TDF_DETAILS) | |
1991 | { | |
1992 | dump_bb (bb, dump_file, 0); | |
1993 | fprintf (dump_file, "\n"); | |
1994 | } | |
1995 | } | |
1996 | ||
1997 | /* Remove all the instructions in the block. */ | |
77568960 | 1998 | for (i = bsi_start (bb); !bsi_end_p (i);) |
6de9cd9a DN |
1999 | { |
2000 | tree stmt = bsi_stmt (i); | |
77568960 AP |
2001 | if (TREE_CODE (stmt) == LABEL_EXPR |
2002 | && FORCED_LABEL (LABEL_EXPR_LABEL (stmt))) | |
2003 | { | |
2004 | basic_block new_bb = bb->prev_bb; | |
2005 | block_stmt_iterator new_bsi = bsi_after_labels (new_bb); | |
2006 | ||
2007 | bsi_remove (&i); | |
2008 | bsi_insert_after (&new_bsi, stmt, BSI_NEW_STMT); | |
2009 | } | |
2010 | else | |
2011 | { | |
2012 | release_defs (stmt); | |
6de9cd9a | 2013 | |
77568960 AP |
2014 | set_bb_for_stmt (stmt, NULL); |
2015 | bsi_remove (&i); | |
2016 | } | |
6de9cd9a DN |
2017 | |
2018 | /* Don't warn for removed gotos. Gotos are often removed due to | |
2019 | jump threading, thus resulting in bogus warnings. Not great, | |
2020 | since this way we lose warnings for gotos in the original | |
2021 | program that are indeed unreachable. */ | |
9506ac2b PB |
2022 | if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc) |
2023 | #ifdef USE_MAPPED_LOCATION | |
2024 | loc = EXPR_LOCATION (stmt); | |
2025 | #else | |
6de9cd9a | 2026 | loc = EXPR_LOCUS (stmt); |
9506ac2b | 2027 | #endif |
6de9cd9a DN |
2028 | } |
2029 | ||
2030 | /* If requested, give a warning that the first statement in the | |
2031 | block is unreachable. We walk statements backwards in the | |
2032 | loop above, so the last statement we process is the first statement | |
2033 | in the block. */ | |
2034 | if (warn_notreached && loc) | |
9506ac2b PB |
2035 | #ifdef USE_MAPPED_LOCATION |
2036 | warning ("%Hwill never be executed", &loc); | |
2037 | #else | |
6de9cd9a | 2038 | warning ("%Hwill never be executed", loc); |
9506ac2b | 2039 | #endif |
6de9cd9a DN |
2040 | |
2041 | remove_phi_nodes_and_edges_for_unreachable_block (bb); | |
2042 | } | |
2043 | ||
6de9cd9a DN |
2044 | /* Try to remove superfluous control structures. */ |
2045 | ||
2046 | static bool | |
2047 | cleanup_control_flow (void) | |
2048 | { | |
2049 | basic_block bb; | |
2050 | block_stmt_iterator bsi; | |
2051 | bool retval = false; | |
2052 | tree stmt; | |
2053 | ||
2054 | FOR_EACH_BB (bb) | |
2055 | { | |
2056 | bsi = bsi_last (bb); | |
2057 | ||
2058 | if (bsi_end_p (bsi)) | |
2059 | continue; | |
2060 | ||
2061 | stmt = bsi_stmt (bsi); | |
2062 | if (TREE_CODE (stmt) == COND_EXPR | |
2063 | || TREE_CODE (stmt) == SWITCH_EXPR) | |
2064 | retval |= cleanup_control_expr_graph (bb, bsi); | |
2065 | } | |
2066 | return retval; | |
2067 | } | |
2068 | ||
2069 | ||
2070 | /* Disconnect an unreachable block in the control expression starting | |
2071 | at block BB. */ | |
2072 | ||
2073 | static bool | |
2074 | cleanup_control_expr_graph (basic_block bb, block_stmt_iterator bsi) | |
2075 | { | |
2076 | edge taken_edge; | |
2077 | bool retval = false; | |
2078 | tree expr = bsi_stmt (bsi), val; | |
2079 | ||
628f6a4e | 2080 | if (EDGE_COUNT (bb->succs) > 1) |
6de9cd9a | 2081 | { |
628f6a4e BE |
2082 | edge e; |
2083 | edge_iterator ei; | |
6de9cd9a DN |
2084 | |
2085 | switch (TREE_CODE (expr)) | |
2086 | { | |
2087 | case COND_EXPR: | |
2088 | val = COND_EXPR_COND (expr); | |
2089 | break; | |
2090 | ||
2091 | case SWITCH_EXPR: | |
2092 | val = SWITCH_COND (expr); | |
2093 | if (TREE_CODE (val) != INTEGER_CST) | |
2094 | return false; | |
2095 | break; | |
2096 | ||
2097 | default: | |
1e128c5f | 2098 | gcc_unreachable (); |
6de9cd9a DN |
2099 | } |
2100 | ||
2101 | taken_edge = find_taken_edge (bb, val); | |
2102 | if (!taken_edge) | |
2103 | return false; | |
2104 | ||
2105 | /* Remove all the edges except the one that is always executed. */ | |
628f6a4e | 2106 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) |
6de9cd9a | 2107 | { |
6de9cd9a DN |
2108 | if (e != taken_edge) |
2109 | { | |
2110 | taken_edge->probability += e->probability; | |
2111 | taken_edge->count += e->count; | |
d0d2cc21 | 2112 | remove_edge (e); |
6de9cd9a DN |
2113 | retval = true; |
2114 | } | |
628f6a4e BE |
2115 | else |
2116 | ei_next (&ei); | |
6de9cd9a DN |
2117 | } |
2118 | if (taken_edge->probability > REG_BR_PROB_BASE) | |
2119 | taken_edge->probability = REG_BR_PROB_BASE; | |
2120 | } | |
2121 | else | |
628f6a4e | 2122 | taken_edge = EDGE_SUCC (bb, 0); |
6de9cd9a DN |
2123 | |
2124 | bsi_remove (&bsi); | |
2125 | taken_edge->flags = EDGE_FALLTHRU; | |
2126 | ||
2127 | /* We removed some paths from the cfg. */ | |
fce22de5 | 2128 | free_dominance_info (CDI_DOMINATORS); |
6de9cd9a DN |
2129 | |
2130 | return retval; | |
2131 | } | |
2132 | ||
2133 | ||
35920270 KH |
2134 | /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a |
2135 | predicate VAL, return the edge that will be taken out of the block. | |
2136 | If VAL does not match a unique edge, NULL is returned. */ | |
6de9cd9a DN |
2137 | |
2138 | edge | |
2139 | find_taken_edge (basic_block bb, tree val) | |
2140 | { | |
2141 | tree stmt; | |
2142 | ||
2143 | stmt = last_stmt (bb); | |
2144 | ||
1e128c5f GB |
2145 | gcc_assert (stmt); |
2146 | gcc_assert (is_ctrl_stmt (stmt)); | |
65f4323d | 2147 | gcc_assert (val); |
6de9cd9a | 2148 | |
255cd731 | 2149 | /* If VAL is a predicate of the form N RELOP N, where N is an |
6a97296a | 2150 | SSA_NAME, we can usually determine its truth value. */ |
65f4323d | 2151 | if (COMPARISON_CLASS_P (val)) |
6a97296a | 2152 | val = fold (val); |
255cd731 | 2153 | |
6de9cd9a DN |
2154 | /* If VAL is not a constant, we can't determine which edge might |
2155 | be taken. */ | |
65f4323d | 2156 | if (!really_constant_p (val)) |
6de9cd9a DN |
2157 | return NULL; |
2158 | ||
2159 | if (TREE_CODE (stmt) == COND_EXPR) | |
2160 | return find_taken_edge_cond_expr (bb, val); | |
2161 | ||
2162 | if (TREE_CODE (stmt) == SWITCH_EXPR) | |
2163 | return find_taken_edge_switch_expr (bb, val); | |
2164 | ||
35920270 | 2165 | gcc_unreachable (); |
6de9cd9a DN |
2166 | } |
2167 | ||
2168 | ||
2169 | /* Given a constant value VAL and the entry block BB to a COND_EXPR | |
2170 | statement, determine which of the two edges will be taken out of the | |
2171 | block. Return NULL if either edge may be taken. */ | |
2172 | ||
2173 | static edge | |
2174 | find_taken_edge_cond_expr (basic_block bb, tree val) | |
2175 | { | |
2176 | edge true_edge, false_edge; | |
2177 | ||
2178 | extract_true_false_edges_from_block (bb, &true_edge, &false_edge); | |
2179 | ||
6de9cd9a DN |
2180 | /* Otherwise, try to determine which branch of the if() will be taken. |
2181 | If VAL is a constant but it can't be reduced to a 0 or a 1, then | |
2182 | we don't really know which edge will be taken at runtime. This | |
2183 | may happen when comparing addresses (e.g., if (&var1 == 4)). */ | |
2184 | if (integer_nonzerop (val)) | |
2185 | return true_edge; | |
2186 | else if (integer_zerop (val)) | |
2187 | return false_edge; | |
2188 | else | |
2189 | return NULL; | |
2190 | } | |
2191 | ||
2192 | ||
2193 | /* Given a constant value VAL and the entry block BB to a SWITCH_EXPR | |
2194 | statement, determine which edge will be taken out of the block. Return | |
2195 | NULL if any edge may be taken. */ | |
2196 | ||
2197 | static edge | |
2198 | find_taken_edge_switch_expr (basic_block bb, tree val) | |
2199 | { | |
2200 | tree switch_expr, taken_case; | |
2201 | basic_block dest_bb; | |
2202 | edge e; | |
2203 | ||
2204 | if (TREE_CODE (val) != INTEGER_CST) | |
2205 | return NULL; | |
2206 | ||
2207 | switch_expr = last_stmt (bb); | |
2208 | taken_case = find_case_label_for_value (switch_expr, val); | |
2209 | dest_bb = label_to_block (CASE_LABEL (taken_case)); | |
2210 | ||
2211 | e = find_edge (bb, dest_bb); | |
1e128c5f | 2212 | gcc_assert (e); |
6de9cd9a DN |
2213 | return e; |
2214 | } | |
2215 | ||
2216 | ||
f667741c SB |
2217 | /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL. |
2218 | We can make optimal use here of the fact that the case labels are | |
2219 | sorted: We can do a binary search for a case matching VAL. */ | |
6de9cd9a DN |
2220 | |
2221 | static tree | |
2222 | find_case_label_for_value (tree switch_expr, tree val) | |
2223 | { | |
2224 | tree vec = SWITCH_LABELS (switch_expr); | |
f667741c SB |
2225 | size_t low, high, n = TREE_VEC_LENGTH (vec); |
2226 | tree default_case = TREE_VEC_ELT (vec, n - 1); | |
6de9cd9a | 2227 | |
f667741c | 2228 | for (low = -1, high = n - 1; high - low > 1; ) |
6de9cd9a | 2229 | { |
f667741c | 2230 | size_t i = (high + low) / 2; |
6de9cd9a | 2231 | tree t = TREE_VEC_ELT (vec, i); |
f667741c SB |
2232 | int cmp; |
2233 | ||
2234 | /* Cache the result of comparing CASE_LOW and val. */ | |
2235 | cmp = tree_int_cst_compare (CASE_LOW (t), val); | |
6de9cd9a | 2236 | |
f667741c SB |
2237 | if (cmp > 0) |
2238 | high = i; | |
2239 | else | |
2240 | low = i; | |
2241 | ||
2242 | if (CASE_HIGH (t) == NULL) | |
6de9cd9a | 2243 | { |
f667741c SB |
2244 | /* A singe-valued case label. */ |
2245 | if (cmp == 0) | |
6de9cd9a DN |
2246 | return t; |
2247 | } | |
2248 | else | |
2249 | { | |
2250 | /* A case range. We can only handle integer ranges. */ | |
f667741c | 2251 | if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0) |
6de9cd9a DN |
2252 | return t; |
2253 | } | |
2254 | } | |
2255 | ||
6de9cd9a DN |
2256 | return default_case; |
2257 | } | |
2258 | ||
2259 | ||
2260 | /* If all the PHI nodes in DEST have alternatives for E1 and E2 and | |
2261 | those alternatives are equal in each of the PHI nodes, then return | |
2262 | true, else return false. */ | |
2263 | ||
2264 | static bool | |
2265 | phi_alternatives_equal (basic_block dest, edge e1, edge e2) | |
2266 | { | |
2267 | tree phi, val1, val2; | |
2268 | int n1, n2; | |
2269 | ||
17192884 | 2270 | for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi)) |
6de9cd9a DN |
2271 | { |
2272 | n1 = phi_arg_from_edge (phi, e1); | |
2273 | n2 = phi_arg_from_edge (phi, e2); | |
2274 | ||
1e128c5f GB |
2275 | gcc_assert (n1 >= 0); |
2276 | gcc_assert (n2 >= 0); | |
6de9cd9a DN |
2277 | |
2278 | val1 = PHI_ARG_DEF (phi, n1); | |
2279 | val2 = PHI_ARG_DEF (phi, n2); | |
2280 | ||
cdef8bc6 | 2281 | if (!operand_equal_for_phi_arg_p (val1, val2)) |
6de9cd9a DN |
2282 | return false; |
2283 | } | |
2284 | ||
2285 | return true; | |
2286 | } | |
2287 | ||
2288 | ||
6de9cd9a DN |
2289 | /*--------------------------------------------------------------------------- |
2290 | Debugging functions | |
2291 | ---------------------------------------------------------------------------*/ | |
2292 | ||
2293 | /* Dump tree-specific information of block BB to file OUTF. */ | |
2294 | ||
2295 | void | |
2296 | tree_dump_bb (basic_block bb, FILE *outf, int indent) | |
2297 | { | |
2298 | dump_generic_bb (outf, bb, indent, TDF_VOPS); | |
2299 | } | |
2300 | ||
2301 | ||
2302 | /* Dump a basic block on stderr. */ | |
2303 | ||
2304 | void | |
2305 | debug_tree_bb (basic_block bb) | |
2306 | { | |
2307 | dump_bb (bb, stderr, 0); | |
2308 | } | |
2309 | ||
2310 | ||
2311 | /* Dump basic block with index N on stderr. */ | |
2312 | ||
2313 | basic_block | |
2314 | debug_tree_bb_n (int n) | |
2315 | { | |
2316 | debug_tree_bb (BASIC_BLOCK (n)); | |
2317 | return BASIC_BLOCK (n); | |
2318 | } | |
2319 | ||
2320 | ||
2321 | /* Dump the CFG on stderr. | |
2322 | ||
2323 | FLAGS are the same used by the tree dumping functions | |
2324 | (see TDF_* in tree.h). */ | |
2325 | ||
2326 | void | |
2327 | debug_tree_cfg (int flags) | |
2328 | { | |
2329 | dump_tree_cfg (stderr, flags); | |
2330 | } | |
2331 | ||
2332 | ||
2333 | /* Dump the program showing basic block boundaries on the given FILE. | |
2334 | ||
2335 | FLAGS are the same used by the tree dumping functions (see TDF_* in | |
2336 | tree.h). */ | |
2337 | ||
2338 | void | |
2339 | dump_tree_cfg (FILE *file, int flags) | |
2340 | { | |
2341 | if (flags & TDF_DETAILS) | |
2342 | { | |
2343 | const char *funcname | |
673fda6b | 2344 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
6de9cd9a DN |
2345 | |
2346 | fputc ('\n', file); | |
2347 | fprintf (file, ";; Function %s\n\n", funcname); | |
2348 | fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n", | |
2349 | n_basic_blocks, n_edges, last_basic_block); | |
2350 | ||
2351 | brief_dump_cfg (file); | |
2352 | fprintf (file, "\n"); | |
2353 | } | |
2354 | ||
2355 | if (flags & TDF_STATS) | |
2356 | dump_cfg_stats (file); | |
2357 | ||
2358 | dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS); | |
2359 | } | |
2360 | ||
2361 | ||
2362 | /* Dump CFG statistics on FILE. */ | |
2363 | ||
2364 | void | |
2365 | dump_cfg_stats (FILE *file) | |
2366 | { | |
2367 | static long max_num_merged_labels = 0; | |
2368 | unsigned long size, total = 0; | |
f7fda749 | 2369 | int n_edges; |
6de9cd9a DN |
2370 | basic_block bb; |
2371 | const char * const fmt_str = "%-30s%-13s%12s\n"; | |
f7fda749 | 2372 | const char * const fmt_str_1 = "%-30s%13d%11lu%c\n"; |
6de9cd9a DN |
2373 | const char * const fmt_str_3 = "%-43s%11lu%c\n"; |
2374 | const char *funcname | |
673fda6b | 2375 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
6de9cd9a DN |
2376 | |
2377 | ||
2378 | fprintf (file, "\nCFG Statistics for %s\n\n", funcname); | |
2379 | ||
2380 | fprintf (file, "---------------------------------------------------------\n"); | |
2381 | fprintf (file, fmt_str, "", " Number of ", "Memory"); | |
2382 | fprintf (file, fmt_str, "", " instances ", "used "); | |
2383 | fprintf (file, "---------------------------------------------------------\n"); | |
2384 | ||
2385 | size = n_basic_blocks * sizeof (struct basic_block_def); | |
2386 | total += size; | |
f7fda749 RH |
2387 | fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks, |
2388 | SCALE (size), LABEL (size)); | |
6de9cd9a DN |
2389 | |
2390 | n_edges = 0; | |
2391 | FOR_EACH_BB (bb) | |
628f6a4e | 2392 | n_edges += EDGE_COUNT (bb->succs); |
6de9cd9a DN |
2393 | size = n_edges * sizeof (struct edge_def); |
2394 | total += size; | |
2395 | fprintf (file, fmt_str_1, "Edges", n_edges, SCALE (size), LABEL (size)); | |
2396 | ||
2397 | size = n_basic_blocks * sizeof (struct bb_ann_d); | |
2398 | total += size; | |
2399 | fprintf (file, fmt_str_1, "Basic block annotations", n_basic_blocks, | |
2400 | SCALE (size), LABEL (size)); | |
2401 | ||
2402 | fprintf (file, "---------------------------------------------------------\n"); | |
2403 | fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total), | |
2404 | LABEL (total)); | |
2405 | fprintf (file, "---------------------------------------------------------\n"); | |
2406 | fprintf (file, "\n"); | |
2407 | ||
2408 | if (cfg_stats.num_merged_labels > max_num_merged_labels) | |
2409 | max_num_merged_labels = cfg_stats.num_merged_labels; | |
2410 | ||
2411 | fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n", | |
2412 | cfg_stats.num_merged_labels, max_num_merged_labels); | |
2413 | ||
2414 | fprintf (file, "\n"); | |
2415 | } | |
2416 | ||
2417 | ||
2418 | /* Dump CFG statistics on stderr. Keep extern so that it's always | |
2419 | linked in the final executable. */ | |
2420 | ||
2421 | void | |
2422 | debug_cfg_stats (void) | |
2423 | { | |
2424 | dump_cfg_stats (stderr); | |
2425 | } | |
2426 | ||
2427 | ||
2428 | /* Dump the flowgraph to a .vcg FILE. */ | |
2429 | ||
2430 | static void | |
2431 | tree_cfg2vcg (FILE *file) | |
2432 | { | |
2433 | edge e; | |
628f6a4e | 2434 | edge_iterator ei; |
6de9cd9a DN |
2435 | basic_block bb; |
2436 | const char *funcname | |
673fda6b | 2437 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
6de9cd9a DN |
2438 | |
2439 | /* Write the file header. */ | |
2440 | fprintf (file, "graph: { title: \"%s\"\n", funcname); | |
2441 | fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n"); | |
2442 | fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n"); | |
2443 | ||
2444 | /* Write blocks and edges. */ | |
628f6a4e | 2445 | FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs) |
6de9cd9a DN |
2446 | { |
2447 | fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"", | |
2448 | e->dest->index); | |
2449 | ||
2450 | if (e->flags & EDGE_FAKE) | |
2451 | fprintf (file, " linestyle: dotted priority: 10"); | |
2452 | else | |
2453 | fprintf (file, " linestyle: solid priority: 100"); | |
2454 | ||
2455 | fprintf (file, " }\n"); | |
2456 | } | |
2457 | fputc ('\n', file); | |
2458 | ||
2459 | FOR_EACH_BB (bb) | |
2460 | { | |
2461 | enum tree_code head_code, end_code; | |
2462 | const char *head_name, *end_name; | |
2463 | int head_line = 0; | |
2464 | int end_line = 0; | |
2465 | tree first = first_stmt (bb); | |
2466 | tree last = last_stmt (bb); | |
2467 | ||
2468 | if (first) | |
2469 | { | |
2470 | head_code = TREE_CODE (first); | |
2471 | head_name = tree_code_name[head_code]; | |
2472 | head_line = get_lineno (first); | |
2473 | } | |
2474 | else | |
2475 | head_name = "no-statement"; | |
2476 | ||
2477 | if (last) | |
2478 | { | |
2479 | end_code = TREE_CODE (last); | |
2480 | end_name = tree_code_name[end_code]; | |
2481 | end_line = get_lineno (last); | |
2482 | } | |
2483 | else | |
2484 | end_name = "no-statement"; | |
2485 | ||
2486 | fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n", | |
2487 | bb->index, bb->index, head_name, head_line, end_name, | |
2488 | end_line); | |
2489 | ||
628f6a4e | 2490 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a DN |
2491 | { |
2492 | if (e->dest == EXIT_BLOCK_PTR) | |
2493 | fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index); | |
2494 | else | |
2495 | fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index); | |
2496 | ||
2497 | if (e->flags & EDGE_FAKE) | |
2498 | fprintf (file, " priority: 10 linestyle: dotted"); | |
2499 | else | |
2500 | fprintf (file, " priority: 100 linestyle: solid"); | |
2501 | ||
2502 | fprintf (file, " }\n"); | |
2503 | } | |
2504 | ||
2505 | if (bb->next_bb != EXIT_BLOCK_PTR) | |
2506 | fputc ('\n', file); | |
2507 | } | |
2508 | ||
2509 | fputs ("}\n\n", file); | |
2510 | } | |
2511 | ||
2512 | ||
2513 | ||
2514 | /*--------------------------------------------------------------------------- | |
2515 | Miscellaneous helpers | |
2516 | ---------------------------------------------------------------------------*/ | |
2517 | ||
2518 | /* Return true if T represents a stmt that always transfers control. */ | |
2519 | ||
2520 | bool | |
2521 | is_ctrl_stmt (tree t) | |
2522 | { | |
2523 | return (TREE_CODE (t) == COND_EXPR | |
2524 | || TREE_CODE (t) == SWITCH_EXPR | |
2525 | || TREE_CODE (t) == GOTO_EXPR | |
2526 | || TREE_CODE (t) == RETURN_EXPR | |
2527 | || TREE_CODE (t) == RESX_EXPR); | |
2528 | } | |
2529 | ||
2530 | ||
2531 | /* Return true if T is a statement that may alter the flow of control | |
2532 | (e.g., a call to a non-returning function). */ | |
2533 | ||
2534 | bool | |
2535 | is_ctrl_altering_stmt (tree t) | |
2536 | { | |
cd709752 | 2537 | tree call; |
6de9cd9a | 2538 | |
1e128c5f | 2539 | gcc_assert (t); |
cd709752 RH |
2540 | call = get_call_expr_in (t); |
2541 | if (call) | |
6de9cd9a | 2542 | { |
6de9cd9a DN |
2543 | /* A non-pure/const CALL_EXPR alters flow control if the current |
2544 | function has nonlocal labels. */ | |
cd709752 | 2545 | if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label) |
6de9cd9a DN |
2546 | return true; |
2547 | ||
2548 | /* A CALL_EXPR also alters control flow if it does not return. */ | |
6e14af16 | 2549 | if (call_expr_flags (call) & ECF_NORETURN) |
6de9cd9a | 2550 | return true; |
6de9cd9a DN |
2551 | } |
2552 | ||
2553 | /* If a statement can throw, it alters control flow. */ | |
2554 | return tree_can_throw_internal (t); | |
2555 | } | |
2556 | ||
2557 | ||
2558 | /* Return true if T is a computed goto. */ | |
2559 | ||
2560 | bool | |
2561 | computed_goto_p (tree t) | |
2562 | { | |
2563 | return (TREE_CODE (t) == GOTO_EXPR | |
2564 | && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL); | |
2565 | } | |
2566 | ||
2567 | ||
2568 | /* Checks whether EXPR is a simple local goto. */ | |
2569 | ||
2570 | bool | |
2571 | simple_goto_p (tree expr) | |
2572 | { | |
ab8907ef RH |
2573 | return (TREE_CODE (expr) == GOTO_EXPR |
2574 | && TREE_CODE (GOTO_DESTINATION (expr)) == LABEL_DECL); | |
6de9cd9a DN |
2575 | } |
2576 | ||
2577 | ||
2578 | /* Return true if T should start a new basic block. PREV_T is the | |
2579 | statement preceding T. It is used when T is a label or a case label. | |
2580 | Labels should only start a new basic block if their previous statement | |
2581 | wasn't a label. Otherwise, sequence of labels would generate | |
2582 | unnecessary basic blocks that only contain a single label. */ | |
2583 | ||
2584 | static inline bool | |
2585 | stmt_starts_bb_p (tree t, tree prev_t) | |
2586 | { | |
2587 | enum tree_code code; | |
2588 | ||
2589 | if (t == NULL_TREE) | |
2590 | return false; | |
2591 | ||
2592 | /* LABEL_EXPRs start a new basic block only if the preceding | |
2593 | statement wasn't a label of the same type. This prevents the | |
2594 | creation of consecutive blocks that have nothing but a single | |
2595 | label. */ | |
2596 | code = TREE_CODE (t); | |
2597 | if (code == LABEL_EXPR) | |
2598 | { | |
2599 | /* Nonlocal and computed GOTO targets always start a new block. */ | |
2600 | if (code == LABEL_EXPR | |
2601 | && (DECL_NONLOCAL (LABEL_EXPR_LABEL (t)) | |
2602 | || FORCED_LABEL (LABEL_EXPR_LABEL (t)))) | |
2603 | return true; | |
2604 | ||
2605 | if (prev_t && TREE_CODE (prev_t) == code) | |
2606 | { | |
2607 | if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t))) | |
2608 | return true; | |
2609 | ||
2610 | cfg_stats.num_merged_labels++; | |
2611 | return false; | |
2612 | } | |
2613 | else | |
2614 | return true; | |
2615 | } | |
2616 | ||
2617 | return false; | |
2618 | } | |
2619 | ||
2620 | ||
2621 | /* Return true if T should end a basic block. */ | |
2622 | ||
2623 | bool | |
2624 | stmt_ends_bb_p (tree t) | |
2625 | { | |
2626 | return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t); | |
2627 | } | |
2628 | ||
2629 | ||
2630 | /* Add gotos that used to be represented implicitly in the CFG. */ | |
2631 | ||
2632 | void | |
2633 | disband_implicit_edges (void) | |
2634 | { | |
2635 | basic_block bb; | |
2636 | block_stmt_iterator last; | |
2637 | edge e; | |
628f6a4e | 2638 | edge_iterator ei; |
eb4e1c01 | 2639 | tree stmt, label; |
6de9cd9a DN |
2640 | |
2641 | FOR_EACH_BB (bb) | |
2642 | { | |
2643 | last = bsi_last (bb); | |
2644 | stmt = last_stmt (bb); | |
2645 | ||
2646 | if (stmt && TREE_CODE (stmt) == COND_EXPR) | |
2647 | { | |
2648 | /* Remove superfluous gotos from COND_EXPR branches. Moved | |
2649 | from cfg_remove_useless_stmts here since it violates the | |
2650 | invariants for tree--cfg correspondence and thus fits better | |
2651 | here where we do it anyway. */ | |
9ff3d2de JL |
2652 | e = find_edge (bb, bb->next_bb); |
2653 | if (e) | |
6de9cd9a | 2654 | { |
6de9cd9a DN |
2655 | if (e->flags & EDGE_TRUE_VALUE) |
2656 | COND_EXPR_THEN (stmt) = build_empty_stmt (); | |
2657 | else if (e->flags & EDGE_FALSE_VALUE) | |
2658 | COND_EXPR_ELSE (stmt) = build_empty_stmt (); | |
2659 | else | |
1e128c5f | 2660 | gcc_unreachable (); |
6de9cd9a DN |
2661 | e->flags |= EDGE_FALLTHRU; |
2662 | } | |
2663 | ||
2664 | continue; | |
2665 | } | |
2666 | ||
2667 | if (stmt && TREE_CODE (stmt) == RETURN_EXPR) | |
2668 | { | |
2669 | /* Remove the RETURN_EXPR if we may fall though to the exit | |
2670 | instead. */ | |
628f6a4e BE |
2671 | gcc_assert (EDGE_COUNT (bb->succs) == 1); |
2672 | gcc_assert (EDGE_SUCC (bb, 0)->dest == EXIT_BLOCK_PTR); | |
6de9cd9a DN |
2673 | |
2674 | if (bb->next_bb == EXIT_BLOCK_PTR | |
2675 | && !TREE_OPERAND (stmt, 0)) | |
2676 | { | |
2677 | bsi_remove (&last); | |
628f6a4e | 2678 | EDGE_SUCC (bb, 0)->flags |= EDGE_FALLTHRU; |
6de9cd9a DN |
2679 | } |
2680 | continue; | |
2681 | } | |
2682 | ||
2683 | /* There can be no fallthru edge if the last statement is a control | |
2684 | one. */ | |
2685 | if (stmt && is_ctrl_stmt (stmt)) | |
2686 | continue; | |
2687 | ||
2688 | /* Find a fallthru edge and emit the goto if necessary. */ | |
628f6a4e | 2689 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a DN |
2690 | if (e->flags & EDGE_FALLTHRU) |
2691 | break; | |
2692 | ||
62b857ea | 2693 | if (!e || e->dest == bb->next_bb) |
6de9cd9a DN |
2694 | continue; |
2695 | ||
1e128c5f | 2696 | gcc_assert (e->dest != EXIT_BLOCK_PTR); |
6de9cd9a DN |
2697 | label = tree_block_label (e->dest); |
2698 | ||
62b857ea | 2699 | stmt = build1 (GOTO_EXPR, void_type_node, label); |
9506ac2b PB |
2700 | #ifdef USE_MAPPED_LOCATION |
2701 | SET_EXPR_LOCATION (stmt, e->goto_locus); | |
2702 | #else | |
62b857ea | 2703 | SET_EXPR_LOCUS (stmt, e->goto_locus); |
9506ac2b | 2704 | #endif |
62b857ea | 2705 | bsi_insert_after (&last, stmt, BSI_NEW_STMT); |
6de9cd9a DN |
2706 | e->flags &= ~EDGE_FALLTHRU; |
2707 | } | |
2708 | } | |
2709 | ||
242229bb | 2710 | /* Remove block annotations and other datastructures. */ |
6de9cd9a DN |
2711 | |
2712 | void | |
242229bb | 2713 | delete_tree_cfg_annotations (void) |
6de9cd9a | 2714 | { |
242229bb | 2715 | basic_block bb; |
6de9cd9a DN |
2716 | if (n_basic_blocks > 0) |
2717 | free_blocks_annotations (); | |
2718 | ||
6de9cd9a DN |
2719 | label_to_block_map = NULL; |
2720 | free_rbi_pool (); | |
242229bb JH |
2721 | FOR_EACH_BB (bb) |
2722 | bb->rbi = NULL; | |
6de9cd9a DN |
2723 | } |
2724 | ||
2725 | ||
2726 | /* Return the first statement in basic block BB. */ | |
2727 | ||
2728 | tree | |
2729 | first_stmt (basic_block bb) | |
2730 | { | |
2731 | block_stmt_iterator i = bsi_start (bb); | |
2732 | return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE; | |
2733 | } | |
2734 | ||
2735 | ||
2736 | /* Return the last statement in basic block BB. */ | |
2737 | ||
2738 | tree | |
2739 | last_stmt (basic_block bb) | |
2740 | { | |
2741 | block_stmt_iterator b = bsi_last (bb); | |
2742 | return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE; | |
2743 | } | |
2744 | ||
2745 | ||
2746 | /* Return a pointer to the last statement in block BB. */ | |
2747 | ||
2748 | tree * | |
2749 | last_stmt_ptr (basic_block bb) | |
2750 | { | |
2751 | block_stmt_iterator last = bsi_last (bb); | |
2752 | return !bsi_end_p (last) ? bsi_stmt_ptr (last) : NULL; | |
2753 | } | |
2754 | ||
2755 | ||
2756 | /* Return the last statement of an otherwise empty block. Return NULL | |
2757 | if the block is totally empty, or if it contains more than one | |
2758 | statement. */ | |
2759 | ||
2760 | tree | |
2761 | last_and_only_stmt (basic_block bb) | |
2762 | { | |
2763 | block_stmt_iterator i = bsi_last (bb); | |
2764 | tree last, prev; | |
2765 | ||
2766 | if (bsi_end_p (i)) | |
2767 | return NULL_TREE; | |
2768 | ||
2769 | last = bsi_stmt (i); | |
2770 | bsi_prev (&i); | |
2771 | if (bsi_end_p (i)) | |
2772 | return last; | |
2773 | ||
2774 | /* Empty statements should no longer appear in the instruction stream. | |
2775 | Everything that might have appeared before should be deleted by | |
2776 | remove_useless_stmts, and the optimizers should just bsi_remove | |
2777 | instead of smashing with build_empty_stmt. | |
2778 | ||
2779 | Thus the only thing that should appear here in a block containing | |
2780 | one executable statement is a label. */ | |
2781 | prev = bsi_stmt (i); | |
2782 | if (TREE_CODE (prev) == LABEL_EXPR) | |
2783 | return last; | |
2784 | else | |
2785 | return NULL_TREE; | |
2786 | } | |
2787 | ||
2788 | ||
2789 | /* Mark BB as the basic block holding statement T. */ | |
2790 | ||
2791 | void | |
2792 | set_bb_for_stmt (tree t, basic_block bb) | |
2793 | { | |
30d396e3 ZD |
2794 | if (TREE_CODE (t) == PHI_NODE) |
2795 | PHI_BB (t) = bb; | |
2796 | else if (TREE_CODE (t) == STATEMENT_LIST) | |
6de9cd9a DN |
2797 | { |
2798 | tree_stmt_iterator i; | |
2799 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
2800 | set_bb_for_stmt (tsi_stmt (i), bb); | |
2801 | } | |
2802 | else | |
2803 | { | |
2804 | stmt_ann_t ann = get_stmt_ann (t); | |
2805 | ann->bb = bb; | |
2806 | ||
2807 | /* If the statement is a label, add the label to block-to-labels map | |
2808 | so that we can speed up edge creation for GOTO_EXPRs. */ | |
2809 | if (TREE_CODE (t) == LABEL_EXPR) | |
2810 | { | |
2811 | int uid; | |
2812 | ||
2813 | t = LABEL_EXPR_LABEL (t); | |
2814 | uid = LABEL_DECL_UID (t); | |
2815 | if (uid == -1) | |
2816 | { | |
2817 | LABEL_DECL_UID (t) = uid = cfun->last_label_uid++; | |
2818 | if (VARRAY_SIZE (label_to_block_map) <= (unsigned) uid) | |
2819 | VARRAY_GROW (label_to_block_map, 3 * uid / 2); | |
2820 | } | |
2821 | else | |
1e128c5f GB |
2822 | /* We're moving an existing label. Make sure that we've |
2823 | removed it from the old block. */ | |
2824 | gcc_assert (!bb || !VARRAY_BB (label_to_block_map, uid)); | |
6de9cd9a DN |
2825 | VARRAY_BB (label_to_block_map, uid) = bb; |
2826 | } | |
2827 | } | |
2828 | } | |
2829 | ||
8b11a64c ZD |
2830 | /* Finds iterator for STMT. */ |
2831 | ||
2832 | extern block_stmt_iterator | |
1a1804c2 | 2833 | bsi_for_stmt (tree stmt) |
8b11a64c ZD |
2834 | { |
2835 | block_stmt_iterator bsi; | |
2836 | ||
2837 | for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi)) | |
2838 | if (bsi_stmt (bsi) == stmt) | |
2839 | return bsi; | |
2840 | ||
1e128c5f | 2841 | gcc_unreachable (); |
8b11a64c | 2842 | } |
6de9cd9a DN |
2843 | |
2844 | /* Insert statement (or statement list) T before the statement | |
2845 | pointed-to by iterator I. M specifies how to update iterator I | |
2846 | after insertion (see enum bsi_iterator_update). */ | |
2847 | ||
2848 | void | |
2849 | bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m) | |
2850 | { | |
2851 | set_bb_for_stmt (t, i->bb); | |
6de9cd9a | 2852 | tsi_link_before (&i->tsi, t, m); |
68b9f53b | 2853 | modify_stmt (t); |
6de9cd9a DN |
2854 | } |
2855 | ||
2856 | ||
2857 | /* Insert statement (or statement list) T after the statement | |
2858 | pointed-to by iterator I. M specifies how to update iterator I | |
2859 | after insertion (see enum bsi_iterator_update). */ | |
2860 | ||
2861 | void | |
2862 | bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m) | |
2863 | { | |
2864 | set_bb_for_stmt (t, i->bb); | |
6de9cd9a | 2865 | tsi_link_after (&i->tsi, t, m); |
68b9f53b | 2866 | modify_stmt (t); |
6de9cd9a DN |
2867 | } |
2868 | ||
2869 | ||
2870 | /* Remove the statement pointed to by iterator I. The iterator is updated | |
2871 | to the next statement. */ | |
2872 | ||
2873 | void | |
2874 | bsi_remove (block_stmt_iterator *i) | |
2875 | { | |
2876 | tree t = bsi_stmt (*i); | |
2877 | set_bb_for_stmt (t, NULL); | |
6de9cd9a DN |
2878 | tsi_delink (&i->tsi); |
2879 | } | |
2880 | ||
2881 | ||
2882 | /* Move the statement at FROM so it comes right after the statement at TO. */ | |
2883 | ||
2884 | void | |
2885 | bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to) | |
2886 | { | |
2887 | tree stmt = bsi_stmt (*from); | |
2888 | bsi_remove (from); | |
2889 | bsi_insert_after (to, stmt, BSI_SAME_STMT); | |
2890 | } | |
2891 | ||
2892 | ||
2893 | /* Move the statement at FROM so it comes right before the statement at TO. */ | |
2894 | ||
2895 | void | |
2896 | bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to) | |
2897 | { | |
2898 | tree stmt = bsi_stmt (*from); | |
2899 | bsi_remove (from); | |
2900 | bsi_insert_before (to, stmt, BSI_SAME_STMT); | |
2901 | } | |
2902 | ||
2903 | ||
2904 | /* Move the statement at FROM to the end of basic block BB. */ | |
2905 | ||
2906 | void | |
2907 | bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb) | |
2908 | { | |
2909 | block_stmt_iterator last = bsi_last (bb); | |
2910 | ||
2911 | /* Have to check bsi_end_p because it could be an empty block. */ | |
2912 | if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last))) | |
2913 | bsi_move_before (from, &last); | |
2914 | else | |
2915 | bsi_move_after (from, &last); | |
2916 | } | |
2917 | ||
2918 | ||
2919 | /* Replace the contents of the statement pointed to by iterator BSI | |
2920 | with STMT. If PRESERVE_EH_INFO is true, the exception handling | |
2921 | information of the original statement is preserved. */ | |
2922 | ||
2923 | void | |
2924 | bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool preserve_eh_info) | |
2925 | { | |
2926 | int eh_region; | |
2927 | tree orig_stmt = bsi_stmt (*bsi); | |
2928 | ||
2929 | SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt)); | |
2930 | set_bb_for_stmt (stmt, bsi->bb); | |
2931 | ||
2932 | /* Preserve EH region information from the original statement, if | |
2933 | requested by the caller. */ | |
2934 | if (preserve_eh_info) | |
2935 | { | |
2936 | eh_region = lookup_stmt_eh_region (orig_stmt); | |
2937 | if (eh_region >= 0) | |
2938 | add_stmt_to_eh_region (stmt, eh_region); | |
2939 | } | |
2940 | ||
2941 | *bsi_stmt_ptr (*bsi) = stmt; | |
2942 | modify_stmt (stmt); | |
2943 | } | |
2944 | ||
2945 | ||
2946 | /* Insert the statement pointed-to by BSI into edge E. Every attempt | |
2947 | is made to place the statement in an existing basic block, but | |
2948 | sometimes that isn't possible. When it isn't possible, the edge is | |
2949 | split and the statement is added to the new block. | |
2950 | ||
2951 | In all cases, the returned *BSI points to the correct location. The | |
2952 | return value is true if insertion should be done after the location, | |
82b85a85 ZD |
2953 | or false if it should be done before the location. If new basic block |
2954 | has to be created, it is stored in *NEW_BB. */ | |
6de9cd9a DN |
2955 | |
2956 | static bool | |
82b85a85 ZD |
2957 | tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi, |
2958 | basic_block *new_bb) | |
6de9cd9a DN |
2959 | { |
2960 | basic_block dest, src; | |
2961 | tree tmp; | |
2962 | ||
2963 | dest = e->dest; | |
2964 | restart: | |
2965 | ||
2966 | /* If the destination has one predecessor which has no PHI nodes, | |
2967 | insert there. Except for the exit block. | |
2968 | ||
2969 | The requirement for no PHI nodes could be relaxed. Basically we | |
2970 | would have to examine the PHIs to prove that none of them used | |
e28d0cfb | 2971 | the value set by the statement we want to insert on E. That |
6de9cd9a | 2972 | hardly seems worth the effort. */ |
628f6a4e | 2973 | if (EDGE_COUNT (dest->preds) == 1 |
6de9cd9a DN |
2974 | && ! phi_nodes (dest) |
2975 | && dest != EXIT_BLOCK_PTR) | |
2976 | { | |
2977 | *bsi = bsi_start (dest); | |
2978 | if (bsi_end_p (*bsi)) | |
2979 | return true; | |
2980 | ||
2981 | /* Make sure we insert after any leading labels. */ | |
2982 | tmp = bsi_stmt (*bsi); | |
2983 | while (TREE_CODE (tmp) == LABEL_EXPR) | |
2984 | { | |
2985 | bsi_next (bsi); | |
2986 | if (bsi_end_p (*bsi)) | |
2987 | break; | |
2988 | tmp = bsi_stmt (*bsi); | |
2989 | } | |
2990 | ||
2991 | if (bsi_end_p (*bsi)) | |
2992 | { | |
2993 | *bsi = bsi_last (dest); | |
2994 | return true; | |
2995 | } | |
2996 | else | |
2997 | return false; | |
2998 | } | |
2999 | ||
3000 | /* If the source has one successor, the edge is not abnormal and | |
3001 | the last statement does not end a basic block, insert there. | |
3002 | Except for the entry block. */ | |
3003 | src = e->src; | |
3004 | if ((e->flags & EDGE_ABNORMAL) == 0 | |
628f6a4e | 3005 | && EDGE_COUNT (src->succs) == 1 |
6de9cd9a DN |
3006 | && src != ENTRY_BLOCK_PTR) |
3007 | { | |
3008 | *bsi = bsi_last (src); | |
3009 | if (bsi_end_p (*bsi)) | |
3010 | return true; | |
3011 | ||
3012 | tmp = bsi_stmt (*bsi); | |
3013 | if (!stmt_ends_bb_p (tmp)) | |
3014 | return true; | |
ce068299 JH |
3015 | |
3016 | /* Insert code just before returning the value. We may need to decompose | |
3017 | the return in the case it contains non-trivial operand. */ | |
3018 | if (TREE_CODE (tmp) == RETURN_EXPR) | |
3019 | { | |
3020 | tree op = TREE_OPERAND (tmp, 0); | |
3021 | if (!is_gimple_val (op)) | |
3022 | { | |
1e128c5f | 3023 | gcc_assert (TREE_CODE (op) == MODIFY_EXPR); |
ce068299 JH |
3024 | bsi_insert_before (bsi, op, BSI_NEW_STMT); |
3025 | TREE_OPERAND (tmp, 0) = TREE_OPERAND (op, 0); | |
3026 | } | |
3027 | bsi_prev (bsi); | |
3028 | return true; | |
3029 | } | |
6de9cd9a DN |
3030 | } |
3031 | ||
3032 | /* Otherwise, create a new basic block, and split this edge. */ | |
3033 | dest = split_edge (e); | |
82b85a85 ZD |
3034 | if (new_bb) |
3035 | *new_bb = dest; | |
628f6a4e | 3036 | e = EDGE_PRED (dest, 0); |
6de9cd9a DN |
3037 | goto restart; |
3038 | } | |
3039 | ||
3040 | ||
3041 | /* This routine will commit all pending edge insertions, creating any new | |
8e731e4e | 3042 | basic blocks which are necessary. */ |
6de9cd9a DN |
3043 | |
3044 | void | |
8e731e4e | 3045 | bsi_commit_edge_inserts (void) |
6de9cd9a DN |
3046 | { |
3047 | basic_block bb; | |
3048 | edge e; | |
628f6a4e | 3049 | edge_iterator ei; |
6de9cd9a | 3050 | |
edfaf675 | 3051 | bsi_commit_one_edge_insert (EDGE_SUCC (ENTRY_BLOCK_PTR, 0), NULL); |
6de9cd9a DN |
3052 | |
3053 | FOR_EACH_BB (bb) | |
628f6a4e | 3054 | FOR_EACH_EDGE (e, ei, bb->succs) |
edfaf675 | 3055 | bsi_commit_one_edge_insert (e, NULL); |
6de9cd9a DN |
3056 | } |
3057 | ||
3058 | ||
edfaf675 AM |
3059 | /* Commit insertions pending at edge E. If a new block is created, set NEW_BB |
3060 | to this block, otherwise set it to NULL. */ | |
6de9cd9a | 3061 | |
edfaf675 AM |
3062 | void |
3063 | bsi_commit_one_edge_insert (edge e, basic_block *new_bb) | |
6de9cd9a | 3064 | { |
edfaf675 AM |
3065 | if (new_bb) |
3066 | *new_bb = NULL; | |
6de9cd9a DN |
3067 | if (PENDING_STMT (e)) |
3068 | { | |
3069 | block_stmt_iterator bsi; | |
3070 | tree stmt = PENDING_STMT (e); | |
3071 | ||
3072 | PENDING_STMT (e) = NULL_TREE; | |
3073 | ||
edfaf675 | 3074 | if (tree_find_edge_insert_loc (e, &bsi, new_bb)) |
6de9cd9a DN |
3075 | bsi_insert_after (&bsi, stmt, BSI_NEW_STMT); |
3076 | else | |
3077 | bsi_insert_before (&bsi, stmt, BSI_NEW_STMT); | |
3078 | } | |
3079 | } | |
3080 | ||
3081 | ||
3082 | /* Add STMT to the pending list of edge E. No actual insertion is | |
3083 | made until a call to bsi_commit_edge_inserts () is made. */ | |
3084 | ||
3085 | void | |
3086 | bsi_insert_on_edge (edge e, tree stmt) | |
3087 | { | |
3088 | append_to_statement_list (stmt, &PENDING_STMT (e)); | |
3089 | } | |
3090 | ||
82b85a85 ZD |
3091 | /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If new block has to |
3092 | be created, it is returned. */ | |
3093 | ||
3094 | basic_block | |
3095 | bsi_insert_on_edge_immediate (edge e, tree stmt) | |
3096 | { | |
3097 | block_stmt_iterator bsi; | |
3098 | basic_block new_bb = NULL; | |
3099 | ||
1e128c5f | 3100 | gcc_assert (!PENDING_STMT (e)); |
82b85a85 ZD |
3101 | |
3102 | if (tree_find_edge_insert_loc (e, &bsi, &new_bb)) | |
3103 | bsi_insert_after (&bsi, stmt, BSI_NEW_STMT); | |
3104 | else | |
3105 | bsi_insert_before (&bsi, stmt, BSI_NEW_STMT); | |
3106 | ||
3107 | return new_bb; | |
3108 | } | |
6de9cd9a | 3109 | |
6de9cd9a DN |
3110 | /*--------------------------------------------------------------------------- |
3111 | Tree specific functions for CFG manipulation | |
3112 | ---------------------------------------------------------------------------*/ | |
3113 | ||
4f7db7f7 KH |
3114 | /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */ |
3115 | ||
3116 | static void | |
3117 | reinstall_phi_args (edge new_edge, edge old_edge) | |
3118 | { | |
3119 | tree var, phi; | |
3120 | ||
3121 | if (!PENDING_STMT (old_edge)) | |
3122 | return; | |
3123 | ||
3124 | for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest); | |
3125 | var && phi; | |
3126 | var = TREE_CHAIN (var), phi = PHI_CHAIN (phi)) | |
3127 | { | |
3128 | tree result = TREE_PURPOSE (var); | |
3129 | tree arg = TREE_VALUE (var); | |
3130 | ||
3131 | gcc_assert (result == PHI_RESULT (phi)); | |
3132 | ||
d2e398df | 3133 | add_phi_arg (phi, arg, new_edge); |
4f7db7f7 KH |
3134 | } |
3135 | ||
3136 | PENDING_STMT (old_edge) = NULL; | |
3137 | } | |
3138 | ||
6de9cd9a DN |
3139 | /* Split a (typically critical) edge EDGE_IN. Return the new block. |
3140 | Abort on abnormal edges. */ | |
3141 | ||
3142 | static basic_block | |
3143 | tree_split_edge (edge edge_in) | |
3144 | { | |
3145 | basic_block new_bb, after_bb, dest, src; | |
3146 | edge new_edge, e; | |
6de9cd9a DN |
3147 | |
3148 | /* Abnormal edges cannot be split. */ | |
1e128c5f | 3149 | gcc_assert (!(edge_in->flags & EDGE_ABNORMAL)); |
6de9cd9a DN |
3150 | |
3151 | src = edge_in->src; | |
3152 | dest = edge_in->dest; | |
3153 | ||
3154 | /* Place the new block in the block list. Try to keep the new block | |
3155 | near its "logical" location. This is of most help to humans looking | |
3156 | at debugging dumps. */ | |
7510740d | 3157 | if (dest->prev_bb && find_edge (dest->prev_bb, dest)) |
6de9cd9a | 3158 | after_bb = edge_in->src; |
7510740d KH |
3159 | else |
3160 | after_bb = dest->prev_bb; | |
6de9cd9a DN |
3161 | |
3162 | new_bb = create_empty_bb (after_bb); | |
b829f3fa JH |
3163 | new_bb->frequency = EDGE_FREQUENCY (edge_in); |
3164 | new_bb->count = edge_in->count; | |
6de9cd9a | 3165 | new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU); |
b829f3fa JH |
3166 | new_edge->probability = REG_BR_PROB_BASE; |
3167 | new_edge->count = edge_in->count; | |
6de9cd9a | 3168 | |
1e128c5f GB |
3169 | e = redirect_edge_and_branch (edge_in, new_bb); |
3170 | gcc_assert (e); | |
4f7db7f7 | 3171 | reinstall_phi_args (new_edge, e); |
6de9cd9a DN |
3172 | |
3173 | return new_bb; | |
3174 | } | |
3175 | ||
3176 | ||
3177 | /* Return true when BB has label LABEL in it. */ | |
3178 | ||
3179 | static bool | |
3180 | has_label_p (basic_block bb, tree label) | |
3181 | { | |
3182 | block_stmt_iterator bsi; | |
3183 | ||
3184 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
3185 | { | |
3186 | tree stmt = bsi_stmt (bsi); | |
3187 | ||
3188 | if (TREE_CODE (stmt) != LABEL_EXPR) | |
3189 | return false; | |
3190 | if (LABEL_EXPR_LABEL (stmt) == label) | |
3191 | return true; | |
3192 | } | |
3193 | return false; | |
3194 | } | |
3195 | ||
3196 | ||
3197 | /* Callback for walk_tree, check that all elements with address taken are | |
3198 | properly noticed as such. */ | |
3199 | ||
3200 | static tree | |
2fbe90f2 | 3201 | verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED) |
6de9cd9a DN |
3202 | { |
3203 | tree t = *tp, x; | |
3204 | ||
3205 | if (TYPE_P (t)) | |
3206 | *walk_subtrees = 0; | |
2fbe90f2 | 3207 | |
50b04185 RK |
3208 | /* Check operand N for being valid GIMPLE and give error MSG if not. |
3209 | We check for constants explicitly since they are not considered | |
3210 | gimple invariants if they overflowed. */ | |
2fbe90f2 | 3211 | #define CHECK_OP(N, MSG) \ |
6615c446 JO |
3212 | do { if (!CONSTANT_CLASS_P (TREE_OPERAND (t, N)) \ |
3213 | && !is_gimple_val (TREE_OPERAND (t, N))) \ | |
2fbe90f2 | 3214 | { error (MSG); return TREE_OPERAND (t, N); }} while (0) |
6de9cd9a DN |
3215 | |
3216 | switch (TREE_CODE (t)) | |
3217 | { | |
3218 | case SSA_NAME: | |
3219 | if (SSA_NAME_IN_FREE_LIST (t)) | |
3220 | { | |
3221 | error ("SSA name in freelist but still referenced"); | |
3222 | return *tp; | |
3223 | } | |
3224 | break; | |
3225 | ||
3226 | case MODIFY_EXPR: | |
3227 | x = TREE_OPERAND (t, 0); | |
3228 | if (TREE_CODE (x) == BIT_FIELD_REF | |
3229 | && is_gimple_reg (TREE_OPERAND (x, 0))) | |
3230 | { | |
3231 | error ("GIMPLE register modified with BIT_FIELD_REF"); | |
2fbe90f2 | 3232 | return t; |
6de9cd9a DN |
3233 | } |
3234 | break; | |
3235 | ||
3236 | case ADDR_EXPR: | |
2fbe90f2 RK |
3237 | /* Skip any references (they will be checked when we recurse down the |
3238 | tree) and ensure that any variable used as a prefix is marked | |
3239 | addressable. */ | |
3240 | for (x = TREE_OPERAND (t, 0); | |
3241 | (handled_component_p (x) | |
3242 | || TREE_CODE (x) == REALPART_EXPR | |
3243 | || TREE_CODE (x) == IMAGPART_EXPR); | |
44de5aeb RK |
3244 | x = TREE_OPERAND (x, 0)) |
3245 | ; | |
3246 | ||
6de9cd9a DN |
3247 | if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL) |
3248 | return NULL; | |
3249 | if (!TREE_ADDRESSABLE (x)) | |
3250 | { | |
3251 | error ("address taken, but ADDRESSABLE bit not set"); | |
3252 | return x; | |
3253 | } | |
3254 | break; | |
3255 | ||
3256 | case COND_EXPR: | |
a6234684 | 3257 | x = COND_EXPR_COND (t); |
6de9cd9a DN |
3258 | if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE) |
3259 | { | |
3260 | error ("non-boolean used in condition"); | |
3261 | return x; | |
3262 | } | |
3263 | break; | |
3264 | ||
3265 | case NOP_EXPR: | |
3266 | case CONVERT_EXPR: | |
3267 | case FIX_TRUNC_EXPR: | |
3268 | case FIX_CEIL_EXPR: | |
3269 | case FIX_FLOOR_EXPR: | |
3270 | case FIX_ROUND_EXPR: | |
3271 | case FLOAT_EXPR: | |
3272 | case NEGATE_EXPR: | |
3273 | case ABS_EXPR: | |
3274 | case BIT_NOT_EXPR: | |
3275 | case NON_LVALUE_EXPR: | |
3276 | case TRUTH_NOT_EXPR: | |
2fbe90f2 | 3277 | CHECK_OP (0, "Invalid operand to unary operator"); |
6de9cd9a DN |
3278 | break; |
3279 | ||
3280 | case REALPART_EXPR: | |
3281 | case IMAGPART_EXPR: | |
2fbe90f2 RK |
3282 | case COMPONENT_REF: |
3283 | case ARRAY_REF: | |
3284 | case ARRAY_RANGE_REF: | |
3285 | case BIT_FIELD_REF: | |
3286 | case VIEW_CONVERT_EXPR: | |
3287 | /* We have a nest of references. Verify that each of the operands | |
3288 | that determine where to reference is either a constant or a variable, | |
3289 | verify that the base is valid, and then show we've already checked | |
3290 | the subtrees. */ | |
3291 | while (TREE_CODE (t) == REALPART_EXPR || TREE_CODE (t) == IMAGPART_EXPR | |
3292 | || handled_component_p (t)) | |
3293 | { | |
3294 | if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2)) | |
3295 | CHECK_OP (2, "Invalid COMPONENT_REF offset operator"); | |
3296 | else if (TREE_CODE (t) == ARRAY_REF | |
3297 | || TREE_CODE (t) == ARRAY_RANGE_REF) | |
3298 | { | |
3299 | CHECK_OP (1, "Invalid array index."); | |
3300 | if (TREE_OPERAND (t, 2)) | |
3301 | CHECK_OP (2, "Invalid array lower bound."); | |
3302 | if (TREE_OPERAND (t, 3)) | |
3303 | CHECK_OP (3, "Invalid array stride."); | |
3304 | } | |
3305 | else if (TREE_CODE (t) == BIT_FIELD_REF) | |
3306 | { | |
3307 | CHECK_OP (1, "Invalid operand to BIT_FIELD_REF"); | |
3308 | CHECK_OP (2, "Invalid operand to BIT_FIELD_REF"); | |
3309 | } | |
3310 | ||
3311 | t = TREE_OPERAND (t, 0); | |
3312 | } | |
3313 | ||
6615c446 | 3314 | if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t)) |
2fbe90f2 RK |
3315 | { |
3316 | error ("Invalid reference prefix."); | |
3317 | return t; | |
3318 | } | |
3319 | *walk_subtrees = 0; | |
6de9cd9a DN |
3320 | break; |
3321 | ||
3322 | case LT_EXPR: | |
3323 | case LE_EXPR: | |
3324 | case GT_EXPR: | |
3325 | case GE_EXPR: | |
3326 | case EQ_EXPR: | |
3327 | case NE_EXPR: | |
3328 | case UNORDERED_EXPR: | |
3329 | case ORDERED_EXPR: | |
3330 | case UNLT_EXPR: | |
3331 | case UNLE_EXPR: | |
3332 | case UNGT_EXPR: | |
3333 | case UNGE_EXPR: | |
3334 | case UNEQ_EXPR: | |
d1a7edaf | 3335 | case LTGT_EXPR: |
6de9cd9a DN |
3336 | case PLUS_EXPR: |
3337 | case MINUS_EXPR: | |
3338 | case MULT_EXPR: | |
3339 | case TRUNC_DIV_EXPR: | |
3340 | case CEIL_DIV_EXPR: | |
3341 | case FLOOR_DIV_EXPR: | |
3342 | case ROUND_DIV_EXPR: | |
3343 | case TRUNC_MOD_EXPR: | |
3344 | case CEIL_MOD_EXPR: | |
3345 | case FLOOR_MOD_EXPR: | |
3346 | case ROUND_MOD_EXPR: | |
3347 | case RDIV_EXPR: | |
3348 | case EXACT_DIV_EXPR: | |
3349 | case MIN_EXPR: | |
3350 | case MAX_EXPR: | |
3351 | case LSHIFT_EXPR: | |
3352 | case RSHIFT_EXPR: | |
3353 | case LROTATE_EXPR: | |
3354 | case RROTATE_EXPR: | |
3355 | case BIT_IOR_EXPR: | |
3356 | case BIT_XOR_EXPR: | |
3357 | case BIT_AND_EXPR: | |
50b04185 RK |
3358 | CHECK_OP (0, "Invalid operand to binary operator"); |
3359 | CHECK_OP (1, "Invalid operand to binary operator"); | |
6de9cd9a DN |
3360 | break; |
3361 | ||
3362 | default: | |
3363 | break; | |
3364 | } | |
3365 | return NULL; | |
2fbe90f2 RK |
3366 | |
3367 | #undef CHECK_OP | |
6de9cd9a DN |
3368 | } |
3369 | ||
3370 | ||
3371 | /* Verify STMT, return true if STMT is not in GIMPLE form. | |
3372 | TODO: Implement type checking. */ | |
3373 | ||
3374 | static bool | |
1eaba2f2 | 3375 | verify_stmt (tree stmt, bool last_in_block) |
6de9cd9a DN |
3376 | { |
3377 | tree addr; | |
3378 | ||
3379 | if (!is_gimple_stmt (stmt)) | |
3380 | { | |
3381 | error ("Is not a valid GIMPLE statement."); | |
1eaba2f2 | 3382 | goto fail; |
6de9cd9a DN |
3383 | } |
3384 | ||
3385 | addr = walk_tree (&stmt, verify_expr, NULL, NULL); | |
3386 | if (addr) | |
3387 | { | |
3388 | debug_generic_stmt (addr); | |
3389 | return true; | |
3390 | } | |
3391 | ||
1eaba2f2 RH |
3392 | /* If the statement is marked as part of an EH region, then it is |
3393 | expected that the statement could throw. Verify that when we | |
3394 | have optimizations that simplify statements such that we prove | |
3395 | that they cannot throw, that we update other data structures | |
3396 | to match. */ | |
3397 | if (lookup_stmt_eh_region (stmt) >= 0) | |
3398 | { | |
3399 | if (!tree_could_throw_p (stmt)) | |
3400 | { | |
971801ff | 3401 | error ("Statement marked for throw, but doesn%'t."); |
1eaba2f2 RH |
3402 | goto fail; |
3403 | } | |
3404 | if (!last_in_block && tree_can_throw_internal (stmt)) | |
3405 | { | |
3406 | error ("Statement marked for throw in middle of block."); | |
3407 | goto fail; | |
3408 | } | |
3409 | } | |
3410 | ||
6de9cd9a | 3411 | return false; |
1eaba2f2 RH |
3412 | |
3413 | fail: | |
3414 | debug_generic_stmt (stmt); | |
3415 | return true; | |
6de9cd9a DN |
3416 | } |
3417 | ||
3418 | ||
3419 | /* Return true when the T can be shared. */ | |
3420 | ||
3421 | static bool | |
3422 | tree_node_can_be_shared (tree t) | |
3423 | { | |
6615c446 | 3424 | if (IS_TYPE_OR_DECL_P (t) |
6de9cd9a DN |
3425 | /* We check for constants explicitly since they are not considered |
3426 | gimple invariants if they overflowed. */ | |
6615c446 | 3427 | || CONSTANT_CLASS_P (t) |
6de9cd9a | 3428 | || is_gimple_min_invariant (t) |
5e23162d | 3429 | || TREE_CODE (t) == SSA_NAME |
bac8beb4 | 3430 | || t == error_mark_node) |
6de9cd9a DN |
3431 | return true; |
3432 | ||
92b6dff3 JL |
3433 | if (TREE_CODE (t) == CASE_LABEL_EXPR) |
3434 | return true; | |
3435 | ||
44de5aeb | 3436 | while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) |
6de9cd9a DN |
3437 | /* We check for constants explicitly since they are not considered |
3438 | gimple invariants if they overflowed. */ | |
6615c446 | 3439 | && (CONSTANT_CLASS_P (TREE_OPERAND (t, 1)) |
6de9cd9a DN |
3440 | || is_gimple_min_invariant (TREE_OPERAND (t, 1)))) |
3441 | || (TREE_CODE (t) == COMPONENT_REF | |
3442 | || TREE_CODE (t) == REALPART_EXPR | |
3443 | || TREE_CODE (t) == IMAGPART_EXPR)) | |
3444 | t = TREE_OPERAND (t, 0); | |
3445 | ||
3446 | if (DECL_P (t)) | |
3447 | return true; | |
3448 | ||
3449 | return false; | |
3450 | } | |
3451 | ||
3452 | ||
3453 | /* Called via walk_trees. Verify tree sharing. */ | |
3454 | ||
3455 | static tree | |
3456 | verify_node_sharing (tree * tp, int *walk_subtrees, void *data) | |
3457 | { | |
3458 | htab_t htab = (htab_t) data; | |
3459 | void **slot; | |
3460 | ||
3461 | if (tree_node_can_be_shared (*tp)) | |
3462 | { | |
3463 | *walk_subtrees = false; | |
3464 | return NULL; | |
3465 | } | |
3466 | ||
3467 | slot = htab_find_slot (htab, *tp, INSERT); | |
3468 | if (*slot) | |
3469 | return *slot; | |
3470 | *slot = *tp; | |
3471 | ||
3472 | return NULL; | |
3473 | } | |
3474 | ||
3475 | ||
3476 | /* Verify the GIMPLE statement chain. */ | |
3477 | ||
3478 | void | |
3479 | verify_stmts (void) | |
3480 | { | |
3481 | basic_block bb; | |
3482 | block_stmt_iterator bsi; | |
3483 | bool err = false; | |
3484 | htab_t htab; | |
3485 | tree addr; | |
3486 | ||
3487 | timevar_push (TV_TREE_STMT_VERIFY); | |
3488 | htab = htab_create (37, htab_hash_pointer, htab_eq_pointer, NULL); | |
3489 | ||
3490 | FOR_EACH_BB (bb) | |
3491 | { | |
3492 | tree phi; | |
3493 | int i; | |
3494 | ||
17192884 | 3495 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
6de9cd9a DN |
3496 | { |
3497 | int phi_num_args = PHI_NUM_ARGS (phi); | |
3498 | ||
3499 | for (i = 0; i < phi_num_args; i++) | |
3500 | { | |
3501 | tree t = PHI_ARG_DEF (phi, i); | |
3502 | tree addr; | |
3503 | ||
3504 | /* Addressable variables do have SSA_NAMEs but they | |
3505 | are not considered gimple values. */ | |
3506 | if (TREE_CODE (t) != SSA_NAME | |
3507 | && TREE_CODE (t) != FUNCTION_DECL | |
3508 | && !is_gimple_val (t)) | |
3509 | { | |
3510 | error ("PHI def is not a GIMPLE value"); | |
3511 | debug_generic_stmt (phi); | |
3512 | debug_generic_stmt (t); | |
3513 | err |= true; | |
3514 | } | |
3515 | ||
3516 | addr = walk_tree (&t, verify_expr, NULL, NULL); | |
3517 | if (addr) | |
3518 | { | |
3519 | debug_generic_stmt (addr); | |
3520 | err |= true; | |
3521 | } | |
3522 | ||
3523 | addr = walk_tree (&t, verify_node_sharing, htab, NULL); | |
3524 | if (addr) | |
3525 | { | |
3526 | error ("Incorrect sharing of tree nodes"); | |
3527 | debug_generic_stmt (phi); | |
3528 | debug_generic_stmt (addr); | |
3529 | err |= true; | |
3530 | } | |
3531 | } | |
3532 | } | |
3533 | ||
1eaba2f2 | 3534 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); ) |
6de9cd9a DN |
3535 | { |
3536 | tree stmt = bsi_stmt (bsi); | |
1eaba2f2 RH |
3537 | bsi_next (&bsi); |
3538 | err |= verify_stmt (stmt, bsi_end_p (bsi)); | |
6de9cd9a DN |
3539 | addr = walk_tree (&stmt, verify_node_sharing, htab, NULL); |
3540 | if (addr) | |
3541 | { | |
3542 | error ("Incorrect sharing of tree nodes"); | |
3543 | debug_generic_stmt (stmt); | |
3544 | debug_generic_stmt (addr); | |
3545 | err |= true; | |
3546 | } | |
3547 | } | |
3548 | } | |
3549 | ||
3550 | if (err) | |
3551 | internal_error ("verify_stmts failed."); | |
3552 | ||
3553 | htab_delete (htab); | |
3554 | timevar_pop (TV_TREE_STMT_VERIFY); | |
3555 | } | |
3556 | ||
3557 | ||
3558 | /* Verifies that the flow information is OK. */ | |
3559 | ||
3560 | static int | |
3561 | tree_verify_flow_info (void) | |
3562 | { | |
3563 | int err = 0; | |
3564 | basic_block bb; | |
3565 | block_stmt_iterator bsi; | |
3566 | tree stmt; | |
3567 | edge e; | |
628f6a4e | 3568 | edge_iterator ei; |
6de9cd9a DN |
3569 | |
3570 | if (ENTRY_BLOCK_PTR->stmt_list) | |
3571 | { | |
3572 | error ("ENTRY_BLOCK has a statement list associated with it\n"); | |
3573 | err = 1; | |
3574 | } | |
3575 | ||
3576 | if (EXIT_BLOCK_PTR->stmt_list) | |
3577 | { | |
3578 | error ("EXIT_BLOCK has a statement list associated with it\n"); | |
3579 | err = 1; | |
3580 | } | |
3581 | ||
628f6a4e | 3582 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds) |
6de9cd9a DN |
3583 | if (e->flags & EDGE_FALLTHRU) |
3584 | { | |
3585 | error ("Fallthru to exit from bb %d\n", e->src->index); | |
3586 | err = 1; | |
3587 | } | |
3588 | ||
3589 | FOR_EACH_BB (bb) | |
3590 | { | |
3591 | bool found_ctrl_stmt = false; | |
3592 | ||
3593 | /* Skip labels on the start of basic block. */ | |
3594 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
3595 | { | |
3596 | if (TREE_CODE (bsi_stmt (bsi)) != LABEL_EXPR) | |
3597 | break; | |
3598 | ||
3599 | if (label_to_block (LABEL_EXPR_LABEL (bsi_stmt (bsi))) != bb) | |
3600 | { | |
77568960 | 3601 | tree stmt = bsi_stmt (bsi); |
6de9cd9a | 3602 | error ("Label %s to block does not match in bb %d\n", |
77568960 | 3603 | IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt))), |
6de9cd9a DN |
3604 | bb->index); |
3605 | err = 1; | |
3606 | } | |
3607 | ||
3608 | if (decl_function_context (LABEL_EXPR_LABEL (bsi_stmt (bsi))) | |
3609 | != current_function_decl) | |
3610 | { | |
77568960 | 3611 | tree stmt = bsi_stmt (bsi); |
6de9cd9a | 3612 | error ("Label %s has incorrect context in bb %d\n", |
77568960 | 3613 | IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt))), |
6de9cd9a DN |
3614 | bb->index); |
3615 | err = 1; | |
3616 | } | |
3617 | } | |
3618 | ||
3619 | /* Verify that body of basic block BB is free of control flow. */ | |
3620 | for (; !bsi_end_p (bsi); bsi_next (&bsi)) | |
3621 | { | |
3622 | tree stmt = bsi_stmt (bsi); | |
3623 | ||
3624 | if (found_ctrl_stmt) | |
3625 | { | |
3626 | error ("Control flow in the middle of basic block %d\n", | |
3627 | bb->index); | |
3628 | err = 1; | |
3629 | } | |
3630 | ||
3631 | if (stmt_ends_bb_p (stmt)) | |
3632 | found_ctrl_stmt = true; | |
3633 | ||
3634 | if (TREE_CODE (stmt) == LABEL_EXPR) | |
3635 | { | |
3636 | error ("Label %s in the middle of basic block %d\n", | |
3637 | IDENTIFIER_POINTER (DECL_NAME (stmt)), | |
3638 | bb->index); | |
3639 | err = 1; | |
3640 | } | |
3641 | } | |
3642 | bsi = bsi_last (bb); | |
3643 | if (bsi_end_p (bsi)) | |
3644 | continue; | |
3645 | ||
3646 | stmt = bsi_stmt (bsi); | |
3647 | ||
3648 | if (is_ctrl_stmt (stmt)) | |
3649 | { | |
628f6a4e | 3650 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a DN |
3651 | if (e->flags & EDGE_FALLTHRU) |
3652 | { | |
3653 | error ("Fallthru edge after a control statement in bb %d \n", | |
3654 | bb->index); | |
3655 | err = 1; | |
3656 | } | |
3657 | } | |
3658 | ||
3659 | switch (TREE_CODE (stmt)) | |
3660 | { | |
3661 | case COND_EXPR: | |
3662 | { | |
3663 | edge true_edge; | |
3664 | edge false_edge; | |
3665 | if (TREE_CODE (COND_EXPR_THEN (stmt)) != GOTO_EXPR | |
3666 | || TREE_CODE (COND_EXPR_ELSE (stmt)) != GOTO_EXPR) | |
3667 | { | |
3668 | error ("Structured COND_EXPR at the end of bb %d\n", bb->index); | |
3669 | err = 1; | |
3670 | } | |
3671 | ||
3672 | extract_true_false_edges_from_block (bb, &true_edge, &false_edge); | |
3673 | ||
3674 | if (!true_edge || !false_edge | |
3675 | || !(true_edge->flags & EDGE_TRUE_VALUE) | |
3676 | || !(false_edge->flags & EDGE_FALSE_VALUE) | |
3677 | || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL)) | |
3678 | || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL)) | |
628f6a4e | 3679 | || EDGE_COUNT (bb->succs) >= 3) |
6de9cd9a DN |
3680 | { |
3681 | error ("Wrong outgoing edge flags at end of bb %d\n", | |
3682 | bb->index); | |
3683 | err = 1; | |
3684 | } | |
3685 | ||
3686 | if (!has_label_p (true_edge->dest, | |
3687 | GOTO_DESTINATION (COND_EXPR_THEN (stmt)))) | |
3688 | { | |
971801ff | 3689 | error ("%<then%> label does not match edge at end of bb %d\n", |
6de9cd9a DN |
3690 | bb->index); |
3691 | err = 1; | |
3692 | } | |
3693 | ||
3694 | if (!has_label_p (false_edge->dest, | |
3695 | GOTO_DESTINATION (COND_EXPR_ELSE (stmt)))) | |
3696 | { | |
971801ff | 3697 | error ("%<else%> label does not match edge at end of bb %d\n", |
6de9cd9a DN |
3698 | bb->index); |
3699 | err = 1; | |
3700 | } | |
3701 | } | |
3702 | break; | |
3703 | ||
3704 | case GOTO_EXPR: | |
3705 | if (simple_goto_p (stmt)) | |
3706 | { | |
3707 | error ("Explicit goto at end of bb %d\n", bb->index); | |
3708 | err = 1; | |
3709 | } | |
3710 | else | |
3711 | { | |
3712 | /* FIXME. We should double check that the labels in the | |
3713 | destination blocks have their address taken. */ | |
628f6a4e | 3714 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a DN |
3715 | if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE |
3716 | | EDGE_FALSE_VALUE)) | |
3717 | || !(e->flags & EDGE_ABNORMAL)) | |
3718 | { | |
3719 | error ("Wrong outgoing edge flags at end of bb %d\n", | |
3720 | bb->index); | |
3721 | err = 1; | |
3722 | } | |
3723 | } | |
3724 | break; | |
3725 | ||
3726 | case RETURN_EXPR: | |
628f6a4e BE |
3727 | if (EDGE_COUNT (bb->succs) != 1 |
3728 | || (EDGE_SUCC (bb, 0)->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL | |
6de9cd9a DN |
3729 | | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))) |
3730 | { | |
3731 | error ("Wrong outgoing edge flags at end of bb %d\n", bb->index); | |
3732 | err = 1; | |
3733 | } | |
628f6a4e | 3734 | if (EDGE_SUCC (bb, 0)->dest != EXIT_BLOCK_PTR) |
6de9cd9a DN |
3735 | { |
3736 | error ("Return edge does not point to exit in bb %d\n", | |
3737 | bb->index); | |
3738 | err = 1; | |
3739 | } | |
3740 | break; | |
3741 | ||
3742 | case SWITCH_EXPR: | |
3743 | { | |
7853504d | 3744 | tree prev; |
6de9cd9a DN |
3745 | edge e; |
3746 | size_t i, n; | |
3747 | tree vec; | |
3748 | ||
3749 | vec = SWITCH_LABELS (stmt); | |
3750 | n = TREE_VEC_LENGTH (vec); | |
3751 | ||
3752 | /* Mark all the destination basic blocks. */ | |
3753 | for (i = 0; i < n; ++i) | |
3754 | { | |
3755 | tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i)); | |
3756 | basic_block label_bb = label_to_block (lab); | |
3757 | ||
1e128c5f | 3758 | gcc_assert (!label_bb->aux || label_bb->aux == (void *)1); |
6de9cd9a DN |
3759 | label_bb->aux = (void *)1; |
3760 | } | |
3761 | ||
7853504d SB |
3762 | /* Verify that the case labels are sorted. */ |
3763 | prev = TREE_VEC_ELT (vec, 0); | |
3764 | for (i = 1; i < n - 1; ++i) | |
3765 | { | |
3766 | tree c = TREE_VEC_ELT (vec, i); | |
3767 | if (! CASE_LOW (c)) | |
3768 | { | |
3769 | error ("Found default case not at end of case vector"); | |
3770 | err = 1; | |
3771 | continue; | |
3772 | } | |
3773 | if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c))) | |
3774 | { | |
3775 | error ("Case labels not sorted:\n "); | |
3776 | print_generic_expr (stderr, prev, 0); | |
3777 | fprintf (stderr," is greater than "); | |
3778 | print_generic_expr (stderr, c, 0); | |
3779 | fprintf (stderr," but comes before it.\n"); | |
3780 | err = 1; | |
3781 | } | |
3782 | prev = c; | |
3783 | } | |
3784 | if (CASE_LOW (TREE_VEC_ELT (vec, n - 1))) | |
3785 | { | |
3786 | error ("No default case found at end of case vector"); | |
3787 | err = 1; | |
3788 | } | |
3789 | ||
628f6a4e | 3790 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a DN |
3791 | { |
3792 | if (!e->dest->aux) | |
3793 | { | |
3794 | error ("Extra outgoing edge %d->%d\n", | |
3795 | bb->index, e->dest->index); | |
3796 | err = 1; | |
3797 | } | |
3798 | e->dest->aux = (void *)2; | |
3799 | if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL | |
3800 | | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))) | |
3801 | { | |
3802 | error ("Wrong outgoing edge flags at end of bb %d\n", | |
3803 | bb->index); | |
3804 | err = 1; | |
3805 | } | |
3806 | } | |
3807 | ||
3808 | /* Check that we have all of them. */ | |
3809 | for (i = 0; i < n; ++i) | |
3810 | { | |
3811 | tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i)); | |
3812 | basic_block label_bb = label_to_block (lab); | |
3813 | ||
3814 | if (label_bb->aux != (void *)2) | |
3815 | { | |
6ade0959 | 3816 | error ("Missing edge %i->%i", |
6de9cd9a DN |
3817 | bb->index, label_bb->index); |
3818 | err = 1; | |
3819 | } | |
3820 | } | |
3821 | ||
628f6a4e | 3822 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a DN |
3823 | e->dest->aux = (void *)0; |
3824 | } | |
3825 | ||
3826 | default: ; | |
3827 | } | |
3828 | } | |
3829 | ||
3830 | if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY) | |
3831 | verify_dominators (CDI_DOMINATORS); | |
3832 | ||
3833 | return err; | |
3834 | } | |
3835 | ||
3836 | ||
f0b698c1 | 3837 | /* Updates phi nodes after creating a forwarder block joined |
6de9cd9a DN |
3838 | by edge FALLTHRU. */ |
3839 | ||
3840 | static void | |
3841 | tree_make_forwarder_block (edge fallthru) | |
3842 | { | |
3843 | edge e; | |
628f6a4e | 3844 | edge_iterator ei; |
6de9cd9a | 3845 | basic_block dummy, bb; |
5ae71719 | 3846 | tree phi, new_phi, var; |
6de9cd9a DN |
3847 | |
3848 | dummy = fallthru->src; | |
3849 | bb = fallthru->dest; | |
3850 | ||
628f6a4e | 3851 | if (EDGE_COUNT (bb->preds) == 1) |
6de9cd9a DN |
3852 | return; |
3853 | ||
3854 | /* If we redirected a branch we must create new phi nodes at the | |
3855 | start of BB. */ | |
17192884 | 3856 | for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi)) |
6de9cd9a DN |
3857 | { |
3858 | var = PHI_RESULT (phi); | |
3859 | new_phi = create_phi_node (var, bb); | |
3860 | SSA_NAME_DEF_STMT (var) = new_phi; | |
d00ad49b | 3861 | SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi)); |
d2e398df | 3862 | add_phi_arg (new_phi, PHI_RESULT (phi), fallthru); |
6de9cd9a DN |
3863 | } |
3864 | ||
17192884 | 3865 | /* Ensure that the PHI node chain is in the same order. */ |
5ae71719 | 3866 | set_phi_nodes (bb, phi_reverse (phi_nodes (bb))); |
6de9cd9a DN |
3867 | |
3868 | /* Add the arguments we have stored on edges. */ | |
628f6a4e | 3869 | FOR_EACH_EDGE (e, ei, bb->preds) |
6de9cd9a DN |
3870 | { |
3871 | if (e == fallthru) | |
3872 | continue; | |
3873 | ||
71882046 | 3874 | flush_pending_stmts (e); |
6de9cd9a DN |
3875 | } |
3876 | } | |
3877 | ||
3878 | ||
3879 | /* Return true if basic block BB does nothing except pass control | |
3880 | flow to another block and that we can safely insert a label at | |
10a52335 KH |
3881 | the start of the successor block. |
3882 | ||
3883 | As a precondition, we require that BB be not equal to | |
3884 | ENTRY_BLOCK_PTR. */ | |
6de9cd9a DN |
3885 | |
3886 | static bool | |
3887 | tree_forwarder_block_p (basic_block bb) | |
3888 | { | |
3889 | block_stmt_iterator bsi; | |
6de9cd9a | 3890 | |
10a52335 | 3891 | /* BB must have a single outgoing edge. */ |
628f6a4e | 3892 | if (EDGE_COUNT (bb->succs) != 1 |
10a52335 KH |
3893 | /* BB can not have any PHI nodes. This could potentially be |
3894 | relaxed early in compilation if we re-rewrote the variables | |
3895 | appearing in any PHI nodes in forwarder blocks. */ | |
3896 | || phi_nodes (bb) | |
3897 | /* BB may not be a predecessor of EXIT_BLOCK_PTR. */ | |
628f6a4e | 3898 | || EDGE_SUCC (bb, 0)->dest == EXIT_BLOCK_PTR |
10a52335 KH |
3899 | /* BB may not have an abnormal outgoing edge. */ |
3900 | || (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL)) | |
78b6731d | 3901 | return false; |
6de9cd9a | 3902 | |
10a52335 KH |
3903 | #if ENABLE_CHECKING |
3904 | gcc_assert (bb != ENTRY_BLOCK_PTR); | |
3905 | #endif | |
3906 | ||
6de9cd9a DN |
3907 | /* Now walk through the statements. We can ignore labels, anything else |
3908 | means this is not a forwarder block. */ | |
3909 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
3910 | { | |
3911 | tree stmt = bsi_stmt (bsi); | |
3912 | ||
3913 | switch (TREE_CODE (stmt)) | |
3914 | { | |
3915 | case LABEL_EXPR: | |
3916 | if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))) | |
3917 | return false; | |
3918 | break; | |
3919 | ||
3920 | default: | |
6de9cd9a DN |
3921 | return false; |
3922 | } | |
3923 | } | |
3924 | ||
91d9ede4 KH |
3925 | if (find_edge (ENTRY_BLOCK_PTR, bb)) |
3926 | return false; | |
3927 | ||
6de9cd9a DN |
3928 | return true; |
3929 | } | |
3930 | ||
072269d8 KH |
3931 | /* Thread jumps from BB. */ |
3932 | ||
3933 | static bool | |
3934 | thread_jumps_from_bb (basic_block bb) | |
3935 | { | |
3936 | edge_iterator ei; | |
3937 | edge e; | |
3938 | bool retval = false; | |
3939 | ||
3940 | /* Examine each of our block's successors to see if it is | |
3941 | forwardable. */ | |
3942 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) | |
3943 | { | |
3944 | int freq; | |
3945 | gcov_type count; | |
3946 | edge last, old; | |
3947 | basic_block dest, tmp, curr, old_dest; | |
3948 | tree phi; | |
3949 | int arg; | |
3950 | ||
3951 | /* If the edge is abnormal or its destination is not | |
3952 | forwardable, then there's nothing to do. */ | |
3953 | if ((e->flags & EDGE_ABNORMAL) | |
3954 | || !bb_ann (e->dest)->forwardable) | |
3955 | { | |
3956 | ei_next (&ei); | |
3957 | continue; | |
3958 | } | |
3959 | ||
072269d8 KH |
3960 | /* Now walk through as many forwarder blocks as possible to find |
3961 | the ultimate destination we want to thread our jump to. */ | |
3962 | last = EDGE_SUCC (e->dest, 0); | |
3963 | bb_ann (e->dest)->forwardable = 0; | |
3964 | for (dest = EDGE_SUCC (e->dest, 0)->dest; | |
3965 | bb_ann (dest)->forwardable; | |
3966 | last = EDGE_SUCC (dest, 0), | |
3967 | dest = EDGE_SUCC (dest, 0)->dest) | |
3968 | bb_ann (dest)->forwardable = 0; | |
3969 | ||
3970 | /* Reset the forwardable marks to 1. */ | |
3971 | for (tmp = e->dest; | |
3972 | tmp != dest; | |
3973 | tmp = EDGE_SUCC (tmp, 0)->dest) | |
3974 | bb_ann (tmp)->forwardable = 1; | |
3975 | ||
3976 | if (dest == e->dest) | |
3977 | { | |
3978 | ei_next (&ei); | |
3979 | continue; | |
3980 | } | |
3981 | ||
3982 | old = find_edge (bb, dest); | |
3983 | if (old) | |
3984 | { | |
3985 | /* If there already is an edge, check whether the values in | |
3986 | phi nodes differ. */ | |
3987 | if (!phi_alternatives_equal (dest, last, old)) | |
3988 | { | |
3989 | /* The previous block is forwarder. Redirect our jump | |
3990 | to that target instead since we know it has no PHI | |
3991 | nodes that will need updating. */ | |
3992 | dest = last->src; | |
3993 | ||
3994 | /* That might mean that no forwarding at all is | |
3995 | possible. */ | |
3996 | if (dest == e->dest) | |
3997 | { | |
3998 | ei_next (&ei); | |
3999 | continue; | |
4000 | } | |
4001 | ||
4002 | old = find_edge (bb, dest); | |
4003 | } | |
4004 | } | |
4005 | ||
4006 | /* Perform the redirection. */ | |
4007 | retval = true; | |
385efa80 KH |
4008 | count = e->count; |
4009 | freq = EDGE_FREQUENCY (e); | |
072269d8 KH |
4010 | old_dest = e->dest; |
4011 | e = redirect_edge_and_branch (e, dest); | |
4012 | ||
4013 | /* Update the profile. */ | |
4014 | if (profile_status != PROFILE_ABSENT) | |
4015 | for (curr = old_dest; | |
4016 | curr != dest; | |
4017 | curr = EDGE_SUCC (curr, 0)->dest) | |
4018 | { | |
4019 | curr->frequency -= freq; | |
4020 | if (curr->frequency < 0) | |
4021 | curr->frequency = 0; | |
4022 | curr->count -= count; | |
4023 | if (curr->count < 0) | |
4024 | curr->count = 0; | |
4025 | EDGE_SUCC (curr, 0)->count -= count; | |
4026 | if (EDGE_SUCC (curr, 0)->count < 0) | |
4027 | EDGE_SUCC (curr, 0)->count = 0; | |
4028 | } | |
4029 | ||
4030 | if (!old) | |
4031 | { | |
4032 | /* Update PHI nodes. We know that the new argument should | |
4033 | have the same value as the argument associated with LAST. | |
4034 | Otherwise we would have changed our target block | |
4035 | above. */ | |
4036 | for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi)) | |
4037 | { | |
4038 | arg = phi_arg_from_edge (phi, last); | |
4039 | gcc_assert (arg >= 0); | |
d2e398df | 4040 | add_phi_arg (phi, PHI_ARG_DEF (phi, arg), e); |
072269d8 KH |
4041 | } |
4042 | } | |
4043 | ||
4044 | /* Remove the unreachable blocks (observe that if all blocks | |
4045 | were reachable before, only those in the path we threaded | |
4046 | over and did not have any predecessor outside of the path | |
4047 | become unreachable). */ | |
4048 | for (; old_dest != dest; old_dest = tmp) | |
4049 | { | |
4050 | tmp = EDGE_SUCC (old_dest, 0)->dest; | |
4051 | ||
4052 | if (EDGE_COUNT (old_dest->preds) > 0) | |
4053 | break; | |
4054 | ||
4055 | delete_basic_block (old_dest); | |
4056 | } | |
4057 | ||
4058 | /* Update the dominators. */ | |
4059 | if (dom_info_available_p (CDI_DOMINATORS)) | |
4060 | { | |
4061 | /* If the dominator of the destination was in the | |
4062 | path, set its dominator to the start of the | |
4063 | redirected edge. */ | |
4064 | if (get_immediate_dominator (CDI_DOMINATORS, old_dest) == NULL) | |
4065 | set_immediate_dominator (CDI_DOMINATORS, old_dest, bb); | |
4066 | ||
4067 | /* Now proceed like if we forwarded just over one edge at a | |
4068 | time. Algorithm for forwarding edge S --> A over | |
4069 | edge A --> B then is | |
4070 | ||
4071 | if (idom (B) == A | |
4072 | && !dominated_by (S, B)) | |
4073 | idom (B) = idom (A); | |
4074 | recount_idom (A); */ | |
4075 | ||
4076 | for (; old_dest != dest; old_dest = tmp) | |
4077 | { | |
4078 | basic_block dom; | |
4079 | ||
4080 | tmp = EDGE_SUCC (old_dest, 0)->dest; | |
4081 | ||
4082 | if (get_immediate_dominator (CDI_DOMINATORS, tmp) == old_dest | |
4083 | && !dominated_by_p (CDI_DOMINATORS, bb, tmp)) | |
4084 | { | |
4085 | dom = get_immediate_dominator (CDI_DOMINATORS, old_dest); | |
4086 | set_immediate_dominator (CDI_DOMINATORS, tmp, dom); | |
4087 | } | |
4088 | ||
4089 | dom = recount_dominator (CDI_DOMINATORS, old_dest); | |
4090 | set_immediate_dominator (CDI_DOMINATORS, old_dest, dom); | |
4091 | } | |
4092 | } | |
4093 | } | |
4094 | ||
4095 | return retval; | |
4096 | } | |
4097 | ||
6de9cd9a DN |
4098 | |
4099 | /* Thread jumps over empty statements. | |
4100 | ||
4101 | This code should _not_ thread over obviously equivalent conditions | |
2abacef0 KH |
4102 | as that requires nontrivial updates to the SSA graph. |
4103 | ||
4104 | As a precondition, we require that all basic blocks be reachable. | |
4105 | That is, there should be no opportunities left for | |
4106 | delete_unreachable_blocks. */ | |
072269d8 | 4107 | |
6de9cd9a DN |
4108 | static bool |
4109 | thread_jumps (void) | |
4110 | { | |
072269d8 | 4111 | basic_block bb; |
6de9cd9a | 4112 | bool retval = false; |
afc3f396 | 4113 | basic_block *worklist = xmalloc (sizeof (basic_block) * last_basic_block); |
31864f59 | 4114 | basic_block *current = worklist; |
6de9cd9a DN |
4115 | |
4116 | FOR_EACH_BB (bb) | |
08445125 KH |
4117 | { |
4118 | bb_ann (bb)->forwardable = tree_forwarder_block_p (bb); | |
4119 | bb->flags &= ~BB_VISITED; | |
4120 | } | |
6de9cd9a | 4121 | |
af88d4ec KH |
4122 | /* We pretend to have ENTRY_BLOCK_PTR in WORKLIST. This way, |
4123 | ENTRY_BLOCK_PTR will never be entered into WORKLIST. */ | |
4124 | ENTRY_BLOCK_PTR->flags |= BB_VISITED; | |
4125 | ||
afc3f396 KH |
4126 | /* Initialize WORKLIST by putting non-forwarder blocks that |
4127 | immediately precede forwarder blocks because those are the ones | |
4128 | that we know we can thread jumps from. We use BB_VISITED to | |
4129 | indicate whether a given basic block is in WORKLIST or not, | |
4130 | thereby avoiding duplicates in WORKLIST. */ | |
08445125 | 4131 | FOR_EACH_BB (bb) |
6de9cd9a | 4132 | { |
08445125 KH |
4133 | edge_iterator ei; |
4134 | edge e; | |
4135 | ||
4136 | /* We are not interested in finding non-forwarder blocks | |
4137 | directly. We want to find non-forwarder blocks as | |
4138 | predecessors of a forwarder block. */ | |
4139 | if (!bb_ann (bb)->forwardable) | |
4140 | continue; | |
4141 | ||
4142 | /* Now we know BB is a forwarder block. Visit each of its | |
4143 | incoming edges and add to WORKLIST all non-forwarder blocks | |
4144 | among BB's predecessors. */ | |
4145 | FOR_EACH_EDGE (e, ei, bb->preds) | |
6de9cd9a | 4146 | { |
0b371c72 KH |
4147 | /* We don't want to put a duplicate into WORKLIST. */ |
4148 | if ((e->src->flags & BB_VISITED) == 0 | |
4149 | /* We are not interested in threading jumps from a forwarder | |
4150 | block. */ | |
4151 | && !bb_ann (e->src)->forwardable) | |
08445125 KH |
4152 | { |
4153 | e->src->flags |= BB_VISITED; | |
31864f59 | 4154 | *current++ = e->src; |
08445125 KH |
4155 | } |
4156 | } | |
4157 | } | |
6de9cd9a | 4158 | |
08445125 | 4159 | /* Now let's drain WORKLIST. */ |
31864f59 | 4160 | while (worklist != current) |
08445125 | 4161 | { |
31864f59 | 4162 | bb = *--current; |
08445125 | 4163 | |
cf566f7f | 4164 | /* BB is no longer in WORKLIST, so clear BB_VISITED. */ |
08445125 KH |
4165 | bb->flags &= ~BB_VISITED; |
4166 | ||
4167 | if (thread_jumps_from_bb (bb)) | |
4168 | { | |
4169 | retval = true; | |
4170 | ||
4171 | if (tree_forwarder_block_p (bb)) | |
628f6a4e | 4172 | { |
08445125 KH |
4173 | edge_iterator ej; |
4174 | edge f; | |
8a807136 | 4175 | |
08445125 KH |
4176 | bb_ann (bb)->forwardable = true; |
4177 | ||
4178 | /* Attempts to thread through BB may have been blocked | |
4179 | because BB was not a forwarder block before. Now | |
4180 | that BB is a forwarder block, we should revisit BB's | |
4181 | predecessors. */ | |
4182 | FOR_EACH_EDGE (f, ej, bb->preds) | |
4183 | { | |
0b371c72 KH |
4184 | /* We don't want to put a duplicate into WORKLIST. */ |
4185 | if ((f->src->flags & BB_VISITED) == 0 | |
4186 | /* We are not interested in threading jumps from a | |
4187 | forwarder block. */ | |
4188 | && !bb_ann (f->src)->forwardable) | |
08445125 KH |
4189 | { |
4190 | f->src->flags |= BB_VISITED; | |
31864f59 | 4191 | *current++ = f->src; |
08445125 KH |
4192 | } |
4193 | } | |
8a807136 | 4194 | } |
e61d7b78 | 4195 | } |
6de9cd9a | 4196 | } |
08445125 | 4197 | |
af88d4ec KH |
4198 | ENTRY_BLOCK_PTR->flags &= ~BB_VISITED; |
4199 | ||
08445125 | 4200 | free (worklist); |
6de9cd9a DN |
4201 | |
4202 | return retval; | |
4203 | } | |
4204 | ||
4205 | ||
4206 | /* Return a non-special label in the head of basic block BLOCK. | |
4207 | Create one if it doesn't exist. */ | |
4208 | ||
d7621d3c | 4209 | tree |
6de9cd9a DN |
4210 | tree_block_label (basic_block bb) |
4211 | { | |
4212 | block_stmt_iterator i, s = bsi_start (bb); | |
4213 | bool first = true; | |
4214 | tree label, stmt; | |
4215 | ||
4216 | for (i = s; !bsi_end_p (i); first = false, bsi_next (&i)) | |
4217 | { | |
4218 | stmt = bsi_stmt (i); | |
4219 | if (TREE_CODE (stmt) != LABEL_EXPR) | |
4220 | break; | |
4221 | label = LABEL_EXPR_LABEL (stmt); | |
4222 | if (!DECL_NONLOCAL (label)) | |
4223 | { | |
4224 | if (!first) | |
4225 | bsi_move_before (&i, &s); | |
4226 | return label; | |
4227 | } | |
4228 | } | |
4229 | ||
4230 | label = create_artificial_label (); | |
4231 | stmt = build1 (LABEL_EXPR, void_type_node, label); | |
4232 | bsi_insert_before (&s, stmt, BSI_NEW_STMT); | |
4233 | return label; | |
4234 | } | |
4235 | ||
4236 | ||
4237 | /* Attempt to perform edge redirection by replacing a possibly complex | |
4238 | jump instruction by a goto or by removing the jump completely. | |
4239 | This can apply only if all edges now point to the same block. The | |
4240 | parameters and return values are equivalent to | |
4241 | redirect_edge_and_branch. */ | |
4242 | ||
4243 | static edge | |
4244 | tree_try_redirect_by_replacing_jump (edge e, basic_block target) | |
4245 | { | |
4246 | basic_block src = e->src; | |
6de9cd9a DN |
4247 | block_stmt_iterator b; |
4248 | tree stmt; | |
6de9cd9a | 4249 | |
07b43a87 KH |
4250 | /* We can replace or remove a complex jump only when we have exactly |
4251 | two edges. */ | |
4252 | if (EDGE_COUNT (src->succs) != 2 | |
4253 | /* Verify that all targets will be TARGET. Specifically, the | |
4254 | edge that is not E must also go to TARGET. */ | |
4255 | || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target) | |
6de9cd9a DN |
4256 | return NULL; |
4257 | ||
4258 | b = bsi_last (src); | |
4259 | if (bsi_end_p (b)) | |
4260 | return NULL; | |
4261 | stmt = bsi_stmt (b); | |
4262 | ||
4263 | if (TREE_CODE (stmt) == COND_EXPR | |
4264 | || TREE_CODE (stmt) == SWITCH_EXPR) | |
4265 | { | |
4266 | bsi_remove (&b); | |
4267 | e = ssa_redirect_edge (e, target); | |
4268 | e->flags = EDGE_FALLTHRU; | |
4269 | return e; | |
4270 | } | |
4271 | ||
4272 | return NULL; | |
4273 | } | |
4274 | ||
4275 | ||
4276 | /* Redirect E to DEST. Return NULL on failure. Otherwise, return the | |
4277 | edge representing the redirected branch. */ | |
4278 | ||
4279 | static edge | |
4280 | tree_redirect_edge_and_branch (edge e, basic_block dest) | |
4281 | { | |
4282 | basic_block bb = e->src; | |
4283 | block_stmt_iterator bsi; | |
4284 | edge ret; | |
4285 | tree label, stmt; | |
4286 | ||
4287 | if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)) | |
4288 | return NULL; | |
4289 | ||
4290 | if (e->src != ENTRY_BLOCK_PTR | |
4291 | && (ret = tree_try_redirect_by_replacing_jump (e, dest))) | |
4292 | return ret; | |
4293 | ||
4294 | if (e->dest == dest) | |
4295 | return NULL; | |
4296 | ||
4297 | label = tree_block_label (dest); | |
4298 | ||
4299 | bsi = bsi_last (bb); | |
4300 | stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi); | |
4301 | ||
4302 | switch (stmt ? TREE_CODE (stmt) : ERROR_MARK) | |
4303 | { | |
4304 | case COND_EXPR: | |
4305 | stmt = (e->flags & EDGE_TRUE_VALUE | |
4306 | ? COND_EXPR_THEN (stmt) | |
4307 | : COND_EXPR_ELSE (stmt)); | |
4308 | GOTO_DESTINATION (stmt) = label; | |
4309 | break; | |
4310 | ||
4311 | case GOTO_EXPR: | |
4312 | /* No non-abnormal edges should lead from a non-simple goto, and | |
4313 | simple ones should be represented implicitly. */ | |
1e128c5f | 4314 | gcc_unreachable (); |
6de9cd9a DN |
4315 | |
4316 | case SWITCH_EXPR: | |
4317 | { | |
d6be0d7f | 4318 | tree cases = get_cases_for_edge (e, stmt); |
6de9cd9a | 4319 | |
d6be0d7f JL |
4320 | /* If we have a list of cases associated with E, then use it |
4321 | as it's a lot faster than walking the entire case vector. */ | |
4322 | if (cases) | |
6de9cd9a | 4323 | { |
4edbbd3f | 4324 | edge e2 = find_edge (e->src, dest); |
d6be0d7f JL |
4325 | tree last, first; |
4326 | ||
4327 | first = cases; | |
4328 | while (cases) | |
4329 | { | |
4330 | last = cases; | |
4331 | CASE_LABEL (cases) = label; | |
4332 | cases = TREE_CHAIN (cases); | |
4333 | } | |
4334 | ||
4335 | /* If there was already an edge in the CFG, then we need | |
4336 | to move all the cases associated with E to E2. */ | |
4337 | if (e2) | |
4338 | { | |
4339 | tree cases2 = get_cases_for_edge (e2, stmt); | |
4340 | ||
4341 | TREE_CHAIN (last) = TREE_CHAIN (cases2); | |
4342 | TREE_CHAIN (cases2) = first; | |
4343 | } | |
6de9cd9a | 4344 | } |
92b6dff3 JL |
4345 | else |
4346 | { | |
d6be0d7f JL |
4347 | tree vec = SWITCH_LABELS (stmt); |
4348 | size_t i, n = TREE_VEC_LENGTH (vec); | |
4349 | ||
4350 | for (i = 0; i < n; i++) | |
4351 | { | |
4352 | tree elt = TREE_VEC_ELT (vec, i); | |
4353 | ||
4354 | if (label_to_block (CASE_LABEL (elt)) == e->dest) | |
4355 | CASE_LABEL (elt) = label; | |
4356 | } | |
92b6dff3 | 4357 | } |
d6be0d7f | 4358 | |
92b6dff3 | 4359 | break; |
6de9cd9a | 4360 | } |
6de9cd9a DN |
4361 | |
4362 | case RETURN_EXPR: | |
4363 | bsi_remove (&bsi); | |
4364 | e->flags |= EDGE_FALLTHRU; | |
4365 | break; | |
4366 | ||
4367 | default: | |
4368 | /* Otherwise it must be a fallthru edge, and we don't need to | |
4369 | do anything besides redirecting it. */ | |
1e128c5f | 4370 | gcc_assert (e->flags & EDGE_FALLTHRU); |
6de9cd9a DN |
4371 | break; |
4372 | } | |
4373 | ||
4374 | /* Update/insert PHI nodes as necessary. */ | |
4375 | ||
4376 | /* Now update the edges in the CFG. */ | |
4377 | e = ssa_redirect_edge (e, dest); | |
4378 | ||
4379 | return e; | |
4380 | } | |
4381 | ||
4382 | ||
4383 | /* Simple wrapper, as we can always redirect fallthru edges. */ | |
4384 | ||
4385 | static basic_block | |
4386 | tree_redirect_edge_and_branch_force (edge e, basic_block dest) | |
4387 | { | |
4388 | e = tree_redirect_edge_and_branch (e, dest); | |
1e128c5f | 4389 | gcc_assert (e); |
6de9cd9a DN |
4390 | |
4391 | return NULL; | |
4392 | } | |
4393 | ||
4394 | ||
4395 | /* Splits basic block BB after statement STMT (but at least after the | |
4396 | labels). If STMT is NULL, BB is split just after the labels. */ | |
4397 | ||
4398 | static basic_block | |
4399 | tree_split_block (basic_block bb, void *stmt) | |
4400 | { | |
4401 | block_stmt_iterator bsi, bsi_tgt; | |
4402 | tree act; | |
4403 | basic_block new_bb; | |
4404 | edge e; | |
628f6a4e | 4405 | edge_iterator ei; |
6de9cd9a DN |
4406 | |
4407 | new_bb = create_empty_bb (bb); | |
4408 | ||
4409 | /* Redirect the outgoing edges. */ | |
628f6a4e BE |
4410 | new_bb->succs = bb->succs; |
4411 | bb->succs = NULL; | |
4412 | FOR_EACH_EDGE (e, ei, new_bb->succs) | |
6de9cd9a DN |
4413 | e->src = new_bb; |
4414 | ||
4415 | if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR) | |
4416 | stmt = NULL; | |
4417 | ||
4418 | /* Move everything from BSI to the new basic block. */ | |
4419 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
4420 | { | |
4421 | act = bsi_stmt (bsi); | |
4422 | if (TREE_CODE (act) == LABEL_EXPR) | |
4423 | continue; | |
4424 | ||
4425 | if (!stmt) | |
4426 | break; | |
4427 | ||
4428 | if (stmt == act) | |
4429 | { | |
4430 | bsi_next (&bsi); | |
4431 | break; | |
4432 | } | |
4433 | } | |
4434 | ||
4435 | bsi_tgt = bsi_start (new_bb); | |
4436 | while (!bsi_end_p (bsi)) | |
4437 | { | |
4438 | act = bsi_stmt (bsi); | |
4439 | bsi_remove (&bsi); | |
4440 | bsi_insert_after (&bsi_tgt, act, BSI_NEW_STMT); | |
4441 | } | |
4442 | ||
4443 | return new_bb; | |
4444 | } | |
4445 | ||
4446 | ||
4447 | /* Moves basic block BB after block AFTER. */ | |
4448 | ||
4449 | static bool | |
4450 | tree_move_block_after (basic_block bb, basic_block after) | |
4451 | { | |
4452 | if (bb->prev_bb == after) | |
4453 | return true; | |
4454 | ||
4455 | unlink_block (bb); | |
4456 | link_block (bb, after); | |
4457 | ||
4458 | return true; | |
4459 | } | |
4460 | ||
4461 | ||
4462 | /* Return true if basic_block can be duplicated. */ | |
4463 | ||
4464 | static bool | |
4465 | tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED) | |
4466 | { | |
4467 | return true; | |
4468 | } | |
4469 | ||
6de9cd9a DN |
4470 | /* Create a duplicate of the basic block BB. NOTE: This does not |
4471 | preserve SSA form. */ | |
4472 | ||
4473 | static basic_block | |
4474 | tree_duplicate_bb (basic_block bb) | |
4475 | { | |
4476 | basic_block new_bb; | |
4477 | block_stmt_iterator bsi, bsi_tgt; | |
4c124b4c AM |
4478 | tree phi, val; |
4479 | ssa_op_iter op_iter; | |
6de9cd9a DN |
4480 | |
4481 | new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb); | |
b0382c67 | 4482 | |
42759f1e ZD |
4483 | /* First copy the phi nodes. We do not copy phi node arguments here, |
4484 | since the edges are not ready yet. Keep the chain of phi nodes in | |
4485 | the same order, so that we can add them later. */ | |
bb29d951 | 4486 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
b0382c67 ZD |
4487 | { |
4488 | mark_for_rewrite (PHI_RESULT (phi)); | |
42759f1e | 4489 | create_phi_node (PHI_RESULT (phi), new_bb); |
b0382c67 | 4490 | } |
5ae71719 | 4491 | set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb))); |
b0382c67 | 4492 | |
6de9cd9a DN |
4493 | bsi_tgt = bsi_start (new_bb); |
4494 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
4495 | { | |
4496 | tree stmt = bsi_stmt (bsi); | |
5f240ec4 | 4497 | tree copy; |
6de9cd9a DN |
4498 | |
4499 | if (TREE_CODE (stmt) == LABEL_EXPR) | |
4500 | continue; | |
4501 | ||
b0382c67 ZD |
4502 | /* Record the definitions. */ |
4503 | get_stmt_operands (stmt); | |
4504 | ||
4c124b4c AM |
4505 | FOR_EACH_SSA_TREE_OPERAND (val, stmt, op_iter, SSA_OP_ALL_DEFS) |
4506 | mark_for_rewrite (val); | |
b0382c67 | 4507 | |
5f240ec4 ZD |
4508 | copy = unshare_expr (stmt); |
4509 | ||
4510 | /* Copy also the virtual operands. */ | |
4511 | get_stmt_ann (copy); | |
4512 | copy_virtual_operands (copy, stmt); | |
4513 | ||
4514 | bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT); | |
6de9cd9a DN |
4515 | } |
4516 | ||
4517 | return new_bb; | |
4518 | } | |
4519 | ||
42759f1e ZD |
4520 | /* Basic block BB_COPY was created by code duplication. Add phi node |
4521 | arguments for edges going out of BB_COPY. The blocks that were | |
4522 | duplicated have rbi->duplicated set to one. */ | |
4523 | ||
4524 | void | |
4525 | add_phi_args_after_copy_bb (basic_block bb_copy) | |
4526 | { | |
4527 | basic_block bb, dest; | |
4528 | edge e, e_copy; | |
628f6a4e | 4529 | edge_iterator ei; |
42759f1e ZD |
4530 | tree phi, phi_copy, phi_next, def; |
4531 | ||
4532 | bb = bb_copy->rbi->original; | |
4533 | ||
628f6a4e | 4534 | FOR_EACH_EDGE (e_copy, ei, bb_copy->succs) |
42759f1e ZD |
4535 | { |
4536 | if (!phi_nodes (e_copy->dest)) | |
4537 | continue; | |
4538 | ||
4539 | if (e_copy->dest->rbi->duplicated) | |
4540 | dest = e_copy->dest->rbi->original; | |
4541 | else | |
4542 | dest = e_copy->dest; | |
4543 | ||
4544 | e = find_edge (bb, dest); | |
4545 | if (!e) | |
4546 | { | |
4547 | /* During loop unrolling the target of the latch edge is copied. | |
4548 | In this case we are not looking for edge to dest, but to | |
4549 | duplicated block whose original was dest. */ | |
628f6a4e | 4550 | FOR_EACH_EDGE (e, ei, bb->succs) |
42759f1e ZD |
4551 | if (e->dest->rbi->duplicated |
4552 | && e->dest->rbi->original == dest) | |
4553 | break; | |
4554 | ||
4555 | gcc_assert (e != NULL); | |
4556 | } | |
4557 | ||
4558 | for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest); | |
4559 | phi; | |
eaf0dc02 | 4560 | phi = phi_next, phi_copy = PHI_CHAIN (phi_copy)) |
42759f1e | 4561 | { |
eaf0dc02 | 4562 | phi_next = PHI_CHAIN (phi); |
42759f1e ZD |
4563 | |
4564 | gcc_assert (PHI_RESULT (phi) == PHI_RESULT (phi_copy)); | |
4565 | def = PHI_ARG_DEF_FROM_EDGE (phi, e); | |
d2e398df | 4566 | add_phi_arg (phi_copy, def, e_copy); |
42759f1e ZD |
4567 | } |
4568 | } | |
4569 | } | |
4570 | ||
4571 | /* Blocks in REGION_COPY array of length N_REGION were created by | |
4572 | duplication of basic blocks. Add phi node arguments for edges | |
4573 | going from these blocks. */ | |
4574 | ||
4575 | void | |
4576 | add_phi_args_after_copy (basic_block *region_copy, unsigned n_region) | |
4577 | { | |
4578 | unsigned i; | |
4579 | ||
4580 | for (i = 0; i < n_region; i++) | |
4581 | region_copy[i]->rbi->duplicated = 1; | |
4582 | ||
4583 | for (i = 0; i < n_region; i++) | |
4584 | add_phi_args_after_copy_bb (region_copy[i]); | |
4585 | ||
4586 | for (i = 0; i < n_region; i++) | |
4587 | region_copy[i]->rbi->duplicated = 0; | |
4588 | } | |
4589 | ||
4590 | /* Maps the old ssa name FROM_NAME to TO_NAME. */ | |
4591 | ||
4592 | struct ssa_name_map_entry | |
4593 | { | |
4594 | tree from_name; | |
4595 | tree to_name; | |
4596 | }; | |
4597 | ||
4598 | /* Hash function for ssa_name_map_entry. */ | |
4599 | ||
4600 | static hashval_t | |
4601 | ssa_name_map_entry_hash (const void *entry) | |
4602 | { | |
4603 | const struct ssa_name_map_entry *en = entry; | |
4604 | return SSA_NAME_VERSION (en->from_name); | |
4605 | } | |
4606 | ||
4607 | /* Equality function for ssa_name_map_entry. */ | |
4608 | ||
4609 | static int | |
4610 | ssa_name_map_entry_eq (const void *in_table, const void *ssa_name) | |
4611 | { | |
4612 | const struct ssa_name_map_entry *en = in_table; | |
4613 | ||
4614 | return en->from_name == ssa_name; | |
4615 | } | |
4616 | ||
4617 | /* Allocate duplicates of ssa names in list DEFINITIONS and store the mapping | |
4618 | to MAP. */ | |
4619 | ||
4620 | void | |
4621 | allocate_ssa_names (bitmap definitions, htab_t *map) | |
4622 | { | |
4623 | tree name; | |
4624 | struct ssa_name_map_entry *entry; | |
4625 | PTR *slot; | |
4626 | unsigned ver; | |
87c476a2 | 4627 | bitmap_iterator bi; |
42759f1e ZD |
4628 | |
4629 | if (!*map) | |
4630 | *map = htab_create (10, ssa_name_map_entry_hash, | |
4631 | ssa_name_map_entry_eq, free); | |
87c476a2 | 4632 | EXECUTE_IF_SET_IN_BITMAP (definitions, 0, ver, bi) |
42759f1e ZD |
4633 | { |
4634 | name = ssa_name (ver); | |
4635 | slot = htab_find_slot_with_hash (*map, name, SSA_NAME_VERSION (name), | |
4636 | INSERT); | |
4637 | if (*slot) | |
4638 | entry = *slot; | |
4639 | else | |
4640 | { | |
4641 | entry = xmalloc (sizeof (struct ssa_name_map_entry)); | |
4642 | entry->from_name = name; | |
4643 | *slot = entry; | |
4644 | } | |
4645 | entry->to_name = duplicate_ssa_name (name, SSA_NAME_DEF_STMT (name)); | |
87c476a2 | 4646 | } |
42759f1e ZD |
4647 | } |
4648 | ||
4649 | /* Rewrite the definition DEF in statement STMT to new ssa name as specified | |
4650 | by the mapping MAP. */ | |
4651 | ||
4652 | static void | |
4653 | rewrite_to_new_ssa_names_def (def_operand_p def, tree stmt, htab_t map) | |
4654 | { | |
4655 | tree name = DEF_FROM_PTR (def); | |
4656 | struct ssa_name_map_entry *entry; | |
4657 | ||
4658 | gcc_assert (TREE_CODE (name) == SSA_NAME); | |
4659 | ||
4660 | entry = htab_find_with_hash (map, name, SSA_NAME_VERSION (name)); | |
4661 | if (!entry) | |
4662 | return; | |
4663 | ||
4664 | SET_DEF (def, entry->to_name); | |
4665 | SSA_NAME_DEF_STMT (entry->to_name) = stmt; | |
4666 | } | |
4667 | ||
4668 | /* Rewrite the USE to new ssa name as specified by the mapping MAP. */ | |
4669 | ||
4670 | static void | |
4671 | rewrite_to_new_ssa_names_use (use_operand_p use, htab_t map) | |
4672 | { | |
4673 | tree name = USE_FROM_PTR (use); | |
4674 | struct ssa_name_map_entry *entry; | |
4675 | ||
4676 | if (TREE_CODE (name) != SSA_NAME) | |
4677 | return; | |
4678 | ||
4679 | entry = htab_find_with_hash (map, name, SSA_NAME_VERSION (name)); | |
4680 | if (!entry) | |
4681 | return; | |
4682 | ||
4683 | SET_USE (use, entry->to_name); | |
4684 | } | |
4685 | ||
4686 | /* Rewrite the ssa names in basic block BB to new ones as specified by the | |
4687 | mapping MAP. */ | |
4688 | ||
4689 | void | |
4690 | rewrite_to_new_ssa_names_bb (basic_block bb, htab_t map) | |
4691 | { | |
4692 | unsigned i; | |
4693 | edge e; | |
628f6a4e | 4694 | edge_iterator ei; |
42759f1e ZD |
4695 | tree phi, stmt; |
4696 | block_stmt_iterator bsi; | |
4697 | use_optype uses; | |
4698 | vuse_optype vuses; | |
4699 | def_optype defs; | |
4700 | v_may_def_optype v_may_defs; | |
4701 | v_must_def_optype v_must_defs; | |
4702 | stmt_ann_t ann; | |
4703 | ||
628f6a4e | 4704 | FOR_EACH_EDGE (e, ei, bb->preds) |
42759f1e ZD |
4705 | if (e->flags & EDGE_ABNORMAL) |
4706 | break; | |
4707 | ||
bb29d951 | 4708 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
42759f1e ZD |
4709 | { |
4710 | rewrite_to_new_ssa_names_def (PHI_RESULT_PTR (phi), phi, map); | |
4711 | if (e) | |
4712 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi)) = 1; | |
4713 | } | |
4714 | ||
4715 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) | |
4716 | { | |
4717 | stmt = bsi_stmt (bsi); | |
4718 | get_stmt_operands (stmt); | |
4719 | ann = stmt_ann (stmt); | |
4720 | ||
4721 | uses = USE_OPS (ann); | |
4722 | for (i = 0; i < NUM_USES (uses); i++) | |
4723 | rewrite_to_new_ssa_names_use (USE_OP_PTR (uses, i), map); | |
4724 | ||
4725 | defs = DEF_OPS (ann); | |
4726 | for (i = 0; i < NUM_DEFS (defs); i++) | |
4727 | rewrite_to_new_ssa_names_def (DEF_OP_PTR (defs, i), stmt, map); | |
4728 | ||
4729 | vuses = VUSE_OPS (ann); | |
4730 | for (i = 0; i < NUM_VUSES (vuses); i++) | |
4731 | rewrite_to_new_ssa_names_use (VUSE_OP_PTR (vuses, i), map); | |
4732 | ||
4733 | v_may_defs = V_MAY_DEF_OPS (ann); | |
4734 | for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++) | |
4735 | { | |
4736 | rewrite_to_new_ssa_names_use | |
4737 | (V_MAY_DEF_OP_PTR (v_may_defs, i), map); | |
4738 | rewrite_to_new_ssa_names_def | |
4739 | (V_MAY_DEF_RESULT_PTR (v_may_defs, i), stmt, map); | |
4740 | } | |
4741 | ||
4742 | v_must_defs = V_MUST_DEF_OPS (ann); | |
4743 | for (i = 0; i < NUM_V_MUST_DEFS (v_must_defs); i++) | |
52328bf6 DB |
4744 | { |
4745 | rewrite_to_new_ssa_names_def | |
4746 | (V_MUST_DEF_RESULT_PTR (v_must_defs, i), stmt, map); | |
4747 | rewrite_to_new_ssa_names_use | |
4748 | (V_MUST_DEF_KILL_PTR (v_must_defs, i), map); | |
4749 | } | |
42759f1e ZD |
4750 | } |
4751 | ||
628f6a4e | 4752 | FOR_EACH_EDGE (e, ei, bb->succs) |
bb29d951 | 4753 | for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi)) |
42759f1e ZD |
4754 | { |
4755 | rewrite_to_new_ssa_names_use | |
4756 | (PHI_ARG_DEF_PTR_FROM_EDGE (phi, e), map); | |
4757 | ||
4758 | if (e->flags & EDGE_ABNORMAL) | |
4759 | { | |
4760 | tree op = PHI_ARG_DEF_FROM_EDGE (phi, e); | |
4761 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op) = 1; | |
4762 | } | |
4763 | } | |
4764 | } | |
4765 | ||
4766 | /* Rewrite the ssa names in N_REGION blocks REGION to the new ones as specified | |
4767 | by the mapping MAP. */ | |
4768 | ||
4769 | void | |
4770 | rewrite_to_new_ssa_names (basic_block *region, unsigned n_region, htab_t map) | |
4771 | { | |
4772 | unsigned r; | |
4773 | ||
4774 | for (r = 0; r < n_region; r++) | |
4775 | rewrite_to_new_ssa_names_bb (region[r], map); | |
4776 | } | |
4777 | ||
4778 | /* Duplicates a REGION (set of N_REGION basic blocks) with just a single | |
4779 | important exit edge EXIT. By important we mean that no SSA name defined | |
4780 | inside region is live over the other exit edges of the region. All entry | |
4781 | edges to the region must go to ENTRY->dest. The edge ENTRY is redirected | |
4782 | to the duplicate of the region. SSA form, dominance and loop information | |
4783 | is updated. The new basic blocks are stored to REGION_COPY in the same | |
4784 | order as they had in REGION, provided that REGION_COPY is not NULL. | |
4785 | The function returns false if it is unable to copy the region, | |
4786 | true otherwise. */ | |
4787 | ||
4788 | bool | |
4789 | tree_duplicate_sese_region (edge entry, edge exit, | |
4790 | basic_block *region, unsigned n_region, | |
4791 | basic_block *region_copy) | |
4792 | { | |
4793 | unsigned i, n_doms, ver; | |
4794 | bool free_region_copy = false, copying_header = false; | |
4795 | struct loop *loop = entry->dest->loop_father; | |
4796 | edge exit_copy; | |
4797 | bitmap definitions; | |
71882046 | 4798 | tree phi; |
42759f1e ZD |
4799 | basic_block *doms; |
4800 | htab_t ssa_name_map = NULL; | |
4801 | edge redirected; | |
87c476a2 | 4802 | bitmap_iterator bi; |
42759f1e ZD |
4803 | |
4804 | if (!can_copy_bbs_p (region, n_region)) | |
4805 | return false; | |
4806 | ||
4807 | /* Some sanity checking. Note that we do not check for all possible | |
4808 | missuses of the functions. I.e. if you ask to copy something weird, | |
4809 | it will work, but the state of structures probably will not be | |
4810 | correct. */ | |
4811 | ||
4812 | for (i = 0; i < n_region; i++) | |
4813 | { | |
4814 | /* We do not handle subloops, i.e. all the blocks must belong to the | |
4815 | same loop. */ | |
4816 | if (region[i]->loop_father != loop) | |
4817 | return false; | |
4818 | ||
4819 | if (region[i] != entry->dest | |
4820 | && region[i] == loop->header) | |
4821 | return false; | |
4822 | } | |
4823 | ||
4824 | loop->copy = loop; | |
4825 | ||
4826 | /* In case the function is used for loop header copying (which is the primary | |
4827 | use), ensure that EXIT and its copy will be new latch and entry edges. */ | |
4828 | if (loop->header == entry->dest) | |
4829 | { | |
4830 | copying_header = true; | |
4831 | loop->copy = loop->outer; | |
4832 | ||
4833 | if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src)) | |
4834 | return false; | |
4835 | ||
4836 | for (i = 0; i < n_region; i++) | |
4837 | if (region[i] != exit->src | |
4838 | && dominated_by_p (CDI_DOMINATORS, region[i], exit->src)) | |
4839 | return false; | |
4840 | } | |
4841 | ||
4842 | if (!region_copy) | |
4843 | { | |
4844 | region_copy = xmalloc (sizeof (basic_block) * n_region); | |
4845 | free_region_copy = true; | |
4846 | } | |
4847 | ||
4848 | gcc_assert (!any_marked_for_rewrite_p ()); | |
4849 | ||
4850 | /* Record blocks outside the region that are duplicated by something | |
4851 | inside. */ | |
4852 | doms = xmalloc (sizeof (basic_block) * n_basic_blocks); | |
4853 | n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms); | |
4854 | ||
4855 | copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop); | |
4856 | definitions = marked_ssa_names (); | |
4857 | ||
4858 | if (copying_header) | |
4859 | { | |
4860 | loop->header = exit->dest; | |
4861 | loop->latch = exit->src; | |
4862 | } | |
4863 | ||
4864 | /* Redirect the entry and add the phi node arguments. */ | |
4865 | redirected = redirect_edge_and_branch (entry, entry->dest->rbi->copy); | |
4866 | gcc_assert (redirected != NULL); | |
71882046 | 4867 | flush_pending_stmts (entry); |
42759f1e ZD |
4868 | |
4869 | /* Concerning updating of dominators: We must recount dominators | |
4870 | for entry block and its copy. Anything that is outside of the region, but | |
4871 | was dominated by something inside needs recounting as well. */ | |
4872 | set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src); | |
4873 | doms[n_doms++] = entry->dest->rbi->original; | |
4874 | iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms); | |
4875 | free (doms); | |
4876 | ||
4877 | /* Add the other phi node arguments. */ | |
4878 | add_phi_args_after_copy (region_copy, n_region); | |
4879 | ||
4880 | /* Add phi nodes for definitions at exit. TODO -- once we have immediate | |
4881 | uses, it should be possible to emit phi nodes just for definitions that | |
4882 | are used outside region. */ | |
87c476a2 | 4883 | EXECUTE_IF_SET_IN_BITMAP (definitions, 0, ver, bi) |
42759f1e ZD |
4884 | { |
4885 | tree name = ssa_name (ver); | |
4886 | ||
4887 | phi = create_phi_node (name, exit->dest); | |
d2e398df KH |
4888 | add_phi_arg (phi, name, exit); |
4889 | add_phi_arg (phi, name, exit_copy); | |
42759f1e ZD |
4890 | |
4891 | SSA_NAME_DEF_STMT (name) = phi; | |
87c476a2 | 4892 | } |
42759f1e ZD |
4893 | |
4894 | /* And create new definitions inside region and its copy. TODO -- once we | |
4895 | have immediate uses, it might be better to leave definitions in region | |
4896 | unchanged, create new ssa names for phi nodes on exit, and rewrite | |
4897 | the uses, to avoid changing the copied region. */ | |
4898 | allocate_ssa_names (definitions, &ssa_name_map); | |
4899 | rewrite_to_new_ssa_names (region, n_region, ssa_name_map); | |
4900 | allocate_ssa_names (definitions, &ssa_name_map); | |
4901 | rewrite_to_new_ssa_names (region_copy, n_region, ssa_name_map); | |
4902 | htab_delete (ssa_name_map); | |
4903 | ||
4904 | if (free_region_copy) | |
4905 | free (region_copy); | |
4906 | ||
4907 | unmark_all_for_rewrite (); | |
4908 | BITMAP_XFREE (definitions); | |
4909 | ||
4910 | return true; | |
4911 | } | |
6de9cd9a DN |
4912 | |
4913 | /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */ | |
4914 | ||
4915 | void | |
4916 | dump_function_to_file (tree fn, FILE *file, int flags) | |
4917 | { | |
4918 | tree arg, vars, var; | |
4919 | bool ignore_topmost_bind = false, any_var = false; | |
4920 | basic_block bb; | |
4921 | tree chain; | |
4922 | ||
673fda6b | 4923 | fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2)); |
6de9cd9a DN |
4924 | |
4925 | arg = DECL_ARGUMENTS (fn); | |
4926 | while (arg) | |
4927 | { | |
4928 | print_generic_expr (file, arg, dump_flags); | |
4929 | if (TREE_CHAIN (arg)) | |
4930 | fprintf (file, ", "); | |
4931 | arg = TREE_CHAIN (arg); | |
4932 | } | |
4933 | fprintf (file, ")\n"); | |
4934 | ||
4935 | if (flags & TDF_RAW) | |
4936 | { | |
4937 | dump_node (fn, TDF_SLIM | flags, file); | |
4938 | return; | |
4939 | } | |
4940 | ||
4941 | /* When GIMPLE is lowered, the variables are no longer available in | |
4942 | BIND_EXPRs, so display them separately. */ | |
4943 | if (cfun && cfun->unexpanded_var_list) | |
4944 | { | |
4945 | ignore_topmost_bind = true; | |
4946 | ||
4947 | fprintf (file, "{\n"); | |
4948 | for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars)) | |
4949 | { | |
4950 | var = TREE_VALUE (vars); | |
4951 | ||
4952 | print_generic_decl (file, var, flags); | |
4953 | fprintf (file, "\n"); | |
4954 | ||
4955 | any_var = true; | |
4956 | } | |
4957 | } | |
4958 | ||
4959 | if (basic_block_info) | |
4960 | { | |
4961 | /* Make a CFG based dump. */ | |
878f99d2 | 4962 | check_bb_profile (ENTRY_BLOCK_PTR, file); |
6de9cd9a DN |
4963 | if (!ignore_topmost_bind) |
4964 | fprintf (file, "{\n"); | |
4965 | ||
4966 | if (any_var && n_basic_blocks) | |
4967 | fprintf (file, "\n"); | |
4968 | ||
4969 | FOR_EACH_BB (bb) | |
4970 | dump_generic_bb (file, bb, 2, flags); | |
4971 | ||
4972 | fprintf (file, "}\n"); | |
878f99d2 | 4973 | check_bb_profile (EXIT_BLOCK_PTR, file); |
6de9cd9a DN |
4974 | } |
4975 | else | |
4976 | { | |
4977 | int indent; | |
4978 | ||
4979 | /* Make a tree based dump. */ | |
4980 | chain = DECL_SAVED_TREE (fn); | |
4981 | ||
4982 | if (TREE_CODE (chain) == BIND_EXPR) | |
4983 | { | |
4984 | if (ignore_topmost_bind) | |
4985 | { | |
4986 | chain = BIND_EXPR_BODY (chain); | |
4987 | indent = 2; | |
4988 | } | |
4989 | else | |
4990 | indent = 0; | |
4991 | } | |
4992 | else | |
4993 | { | |
4994 | if (!ignore_topmost_bind) | |
4995 | fprintf (file, "{\n"); | |
4996 | indent = 2; | |
4997 | } | |
4998 | ||
4999 | if (any_var) | |
5000 | fprintf (file, "\n"); | |
5001 | ||
5002 | print_generic_stmt_indented (file, chain, flags, indent); | |
5003 | if (ignore_topmost_bind) | |
5004 | fprintf (file, "}\n"); | |
5005 | } | |
5006 | ||
5007 | fprintf (file, "\n\n"); | |
5008 | } | |
5009 | ||
5010 | ||
5011 | /* Pretty print of the loops intermediate representation. */ | |
5012 | static void print_loop (FILE *, struct loop *, int); | |
628f6a4e BE |
5013 | static void print_pred_bbs (FILE *, basic_block bb); |
5014 | static void print_succ_bbs (FILE *, basic_block bb); | |
6de9cd9a DN |
5015 | |
5016 | ||
5017 | /* Print the predecessors indexes of edge E on FILE. */ | |
5018 | ||
5019 | static void | |
628f6a4e | 5020 | print_pred_bbs (FILE *file, basic_block bb) |
6de9cd9a | 5021 | { |
628f6a4e BE |
5022 | edge e; |
5023 | edge_iterator ei; | |
5024 | ||
5025 | FOR_EACH_EDGE (e, ei, bb->preds) | |
6de9cd9a | 5026 | fprintf (file, "bb_%d", e->src->index); |
6de9cd9a DN |
5027 | } |
5028 | ||
5029 | ||
5030 | /* Print the successors indexes of edge E on FILE. */ | |
5031 | ||
5032 | static void | |
628f6a4e | 5033 | print_succ_bbs (FILE *file, basic_block bb) |
6de9cd9a | 5034 | { |
628f6a4e BE |
5035 | edge e; |
5036 | edge_iterator ei; | |
5037 | ||
5038 | FOR_EACH_EDGE (e, ei, bb->succs) | |
5039 | fprintf (file, "bb_%d", e->src->index); | |
6de9cd9a DN |
5040 | } |
5041 | ||
5042 | ||
5043 | /* Pretty print LOOP on FILE, indented INDENT spaces. */ | |
5044 | ||
5045 | static void | |
5046 | print_loop (FILE *file, struct loop *loop, int indent) | |
5047 | { | |
5048 | char *s_indent; | |
5049 | basic_block bb; | |
5050 | ||
5051 | if (loop == NULL) | |
5052 | return; | |
5053 | ||
5054 | s_indent = (char *) alloca ((size_t) indent + 1); | |
5055 | memset ((void *) s_indent, ' ', (size_t) indent); | |
5056 | s_indent[indent] = '\0'; | |
5057 | ||
5058 | /* Print the loop's header. */ | |
5059 | fprintf (file, "%sloop_%d\n", s_indent, loop->num); | |
5060 | ||
5061 | /* Print the loop's body. */ | |
5062 | fprintf (file, "%s{\n", s_indent); | |
5063 | FOR_EACH_BB (bb) | |
5064 | if (bb->loop_father == loop) | |
5065 | { | |
5066 | /* Print the basic_block's header. */ | |
5067 | fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index); | |
628f6a4e | 5068 | print_pred_bbs (file, bb); |
6de9cd9a | 5069 | fprintf (file, "}, succs = {"); |
628f6a4e | 5070 | print_succ_bbs (file, bb); |
6de9cd9a DN |
5071 | fprintf (file, "})\n"); |
5072 | ||
5073 | /* Print the basic_block's body. */ | |
5074 | fprintf (file, "%s {\n", s_indent); | |
5075 | tree_dump_bb (bb, file, indent + 4); | |
5076 | fprintf (file, "%s }\n", s_indent); | |
5077 | } | |
5078 | ||
5079 | print_loop (file, loop->inner, indent + 2); | |
5080 | fprintf (file, "%s}\n", s_indent); | |
5081 | print_loop (file, loop->next, indent); | |
5082 | } | |
5083 | ||
5084 | ||
5085 | /* Follow a CFG edge from the entry point of the program, and on entry | |
5086 | of a loop, pretty print the loop structure on FILE. */ | |
5087 | ||
5088 | void | |
5089 | print_loop_ir (FILE *file) | |
5090 | { | |
5091 | basic_block bb; | |
5092 | ||
5093 | bb = BASIC_BLOCK (0); | |
5094 | if (bb && bb->loop_father) | |
5095 | print_loop (file, bb->loop_father, 0); | |
5096 | } | |
5097 | ||
5098 | ||
5099 | /* Debugging loops structure at tree level. */ | |
5100 | ||
5101 | void | |
5102 | debug_loop_ir (void) | |
5103 | { | |
5104 | print_loop_ir (stderr); | |
5105 | } | |
5106 | ||
5107 | ||
5108 | /* Return true if BB ends with a call, possibly followed by some | |
5109 | instructions that must stay with the call. Return false, | |
5110 | otherwise. */ | |
5111 | ||
5112 | static bool | |
5113 | tree_block_ends_with_call_p (basic_block bb) | |
5114 | { | |
5115 | block_stmt_iterator bsi = bsi_last (bb); | |
cd709752 | 5116 | return get_call_expr_in (bsi_stmt (bsi)) != NULL; |
6de9cd9a DN |
5117 | } |
5118 | ||
5119 | ||
5120 | /* Return true if BB ends with a conditional branch. Return false, | |
5121 | otherwise. */ | |
5122 | ||
5123 | static bool | |
5124 | tree_block_ends_with_condjump_p (basic_block bb) | |
5125 | { | |
5126 | tree stmt = tsi_stmt (bsi_last (bb).tsi); | |
5127 | return (TREE_CODE (stmt) == COND_EXPR); | |
5128 | } | |
5129 | ||
5130 | ||
5131 | /* Return true if we need to add fake edge to exit at statement T. | |
5132 | Helper function for tree_flow_call_edges_add. */ | |
5133 | ||
5134 | static bool | |
5135 | need_fake_edge_p (tree t) | |
5136 | { | |
cd709752 | 5137 | tree call; |
6de9cd9a DN |
5138 | |
5139 | /* NORETURN and LONGJMP calls already have an edge to exit. | |
5140 | CONST, PURE and ALWAYS_RETURN calls do not need one. | |
5141 | We don't currently check for CONST and PURE here, although | |
5142 | it would be a good idea, because those attributes are | |
5143 | figured out from the RTL in mark_constant_function, and | |
5144 | the counter incrementation code from -fprofile-arcs | |
5145 | leads to different results from -fbranch-probabilities. */ | |
cd709752 RH |
5146 | call = get_call_expr_in (t); |
5147 | if (call | |
6e14af16 | 5148 | && !(call_expr_flags (call) & (ECF_NORETURN | ECF_ALWAYS_RETURN))) |
6de9cd9a DN |
5149 | return true; |
5150 | ||
5151 | if (TREE_CODE (t) == ASM_EXPR | |
5152 | && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t))) | |
5153 | return true; | |
5154 | ||
5155 | return false; | |
5156 | } | |
5157 | ||
5158 | ||
5159 | /* Add fake edges to the function exit for any non constant and non | |
5160 | noreturn calls, volatile inline assembly in the bitmap of blocks | |
5161 | specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return | |
5162 | the number of blocks that were split. | |
5163 | ||
5164 | The goal is to expose cases in which entering a basic block does | |
5165 | not imply that all subsequent instructions must be executed. */ | |
5166 | ||
5167 | static int | |
5168 | tree_flow_call_edges_add (sbitmap blocks) | |
5169 | { | |
5170 | int i; | |
5171 | int blocks_split = 0; | |
5172 | int last_bb = last_basic_block; | |
5173 | bool check_last_block = false; | |
5174 | ||
5175 | if (n_basic_blocks == 0) | |
5176 | return 0; | |
5177 | ||
5178 | if (! blocks) | |
5179 | check_last_block = true; | |
5180 | else | |
5181 | check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index); | |
5182 | ||
5183 | /* In the last basic block, before epilogue generation, there will be | |
5184 | a fallthru edge to EXIT. Special care is required if the last insn | |
5185 | of the last basic block is a call because make_edge folds duplicate | |
5186 | edges, which would result in the fallthru edge also being marked | |
5187 | fake, which would result in the fallthru edge being removed by | |
5188 | remove_fake_edges, which would result in an invalid CFG. | |
5189 | ||
5190 | Moreover, we can't elide the outgoing fake edge, since the block | |
5191 | profiler needs to take this into account in order to solve the minimal | |
5192 | spanning tree in the case that the call doesn't return. | |
5193 | ||
5194 | Handle this by adding a dummy instruction in a new last basic block. */ | |
5195 | if (check_last_block) | |
5196 | { | |
5197 | basic_block bb = EXIT_BLOCK_PTR->prev_bb; | |
5198 | block_stmt_iterator bsi = bsi_last (bb); | |
5199 | tree t = NULL_TREE; | |
5200 | if (!bsi_end_p (bsi)) | |
5201 | t = bsi_stmt (bsi); | |
5202 | ||
5203 | if (need_fake_edge_p (t)) | |
5204 | { | |
5205 | edge e; | |
5206 | ||
9ff3d2de JL |
5207 | e = find_edge (bb, EXIT_BLOCK_PTR); |
5208 | if (e) | |
5209 | { | |
5210 | bsi_insert_on_edge (e, build_empty_stmt ()); | |
5211 | bsi_commit_edge_inserts (); | |
5212 | } | |
6de9cd9a DN |
5213 | } |
5214 | } | |
5215 | ||
5216 | /* Now add fake edges to the function exit for any non constant | |
5217 | calls since there is no way that we can determine if they will | |
5218 | return or not... */ | |
5219 | for (i = 0; i < last_bb; i++) | |
5220 | { | |
5221 | basic_block bb = BASIC_BLOCK (i); | |
5222 | block_stmt_iterator bsi; | |
5223 | tree stmt, last_stmt; | |
5224 | ||
5225 | if (!bb) | |
5226 | continue; | |
5227 | ||
5228 | if (blocks && !TEST_BIT (blocks, i)) | |
5229 | continue; | |
5230 | ||
5231 | bsi = bsi_last (bb); | |
5232 | if (!bsi_end_p (bsi)) | |
5233 | { | |
5234 | last_stmt = bsi_stmt (bsi); | |
5235 | do | |
5236 | { | |
5237 | stmt = bsi_stmt (bsi); | |
5238 | if (need_fake_edge_p (stmt)) | |
5239 | { | |
5240 | edge e; | |
5241 | /* The handling above of the final block before the | |
5242 | epilogue should be enough to verify that there is | |
5243 | no edge to the exit block in CFG already. | |
5244 | Calling make_edge in such case would cause us to | |
5245 | mark that edge as fake and remove it later. */ | |
5246 | #ifdef ENABLE_CHECKING | |
5247 | if (stmt == last_stmt) | |
628f6a4e | 5248 | { |
9ff3d2de JL |
5249 | e = find_edge (bb, EXIT_BLOCK_PTR); |
5250 | gcc_assert (e == NULL); | |
628f6a4e | 5251 | } |
6de9cd9a DN |
5252 | #endif |
5253 | ||
5254 | /* Note that the following may create a new basic block | |
5255 | and renumber the existing basic blocks. */ | |
5256 | if (stmt != last_stmt) | |
5257 | { | |
5258 | e = split_block (bb, stmt); | |
5259 | if (e) | |
5260 | blocks_split++; | |
5261 | } | |
5262 | make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE); | |
5263 | } | |
5264 | bsi_prev (&bsi); | |
5265 | } | |
5266 | while (!bsi_end_p (bsi)); | |
5267 | } | |
5268 | } | |
5269 | ||
5270 | if (blocks_split) | |
5271 | verify_flow_info (); | |
5272 | ||
5273 | return blocks_split; | |
5274 | } | |
5275 | ||
1eaba2f2 RH |
5276 | bool |
5277 | tree_purge_dead_eh_edges (basic_block bb) | |
5278 | { | |
5279 | bool changed = false; | |
628f6a4e BE |
5280 | edge e; |
5281 | edge_iterator ei; | |
1eaba2f2 RH |
5282 | tree stmt = last_stmt (bb); |
5283 | ||
5284 | if (stmt && tree_can_throw_internal (stmt)) | |
5285 | return false; | |
5286 | ||
628f6a4e | 5287 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) |
1eaba2f2 | 5288 | { |
1eaba2f2 RH |
5289 | if (e->flags & EDGE_EH) |
5290 | { | |
d0d2cc21 | 5291 | remove_edge (e); |
1eaba2f2 RH |
5292 | changed = true; |
5293 | } | |
628f6a4e BE |
5294 | else |
5295 | ei_next (&ei); | |
1eaba2f2 RH |
5296 | } |
5297 | ||
69d49802 JJ |
5298 | /* Removal of dead EH edges might change dominators of not |
5299 | just immediate successors. E.g. when bb1 is changed so that | |
5300 | it no longer can throw and bb1->bb3 and bb1->bb4 are dead | |
5301 | eh edges purged by this function in: | |
5302 | 0 | |
5303 | / \ | |
5304 | v v | |
5305 | 1-->2 | |
5306 | / \ | | |
5307 | v v | | |
5308 | 3-->4 | | |
5309 | \ v | |
5310 | --->5 | |
5311 | | | |
5312 | - | |
5313 | idom(bb5) must be recomputed. For now just free the dominance | |
5314 | info. */ | |
5315 | if (changed) | |
5316 | free_dominance_info (CDI_DOMINATORS); | |
5317 | ||
1eaba2f2 RH |
5318 | return changed; |
5319 | } | |
5320 | ||
5321 | bool | |
5322 | tree_purge_all_dead_eh_edges (bitmap blocks) | |
5323 | { | |
5324 | bool changed = false; | |
3cd8c58a | 5325 | unsigned i; |
87c476a2 | 5326 | bitmap_iterator bi; |
1eaba2f2 | 5327 | |
87c476a2 ZD |
5328 | EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi) |
5329 | { | |
5330 | changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i)); | |
5331 | } | |
1eaba2f2 RH |
5332 | |
5333 | return changed; | |
5334 | } | |
6de9cd9a | 5335 | |
a100ac1e KH |
5336 | /* This function is called whenever a new edge is created or |
5337 | redirected. */ | |
5338 | ||
5339 | static void | |
5340 | tree_execute_on_growing_pred (edge e) | |
5341 | { | |
5342 | basic_block bb = e->dest; | |
5343 | ||
5344 | if (phi_nodes (bb)) | |
5345 | reserve_phi_args_for_new_edge (bb); | |
5346 | } | |
5347 | ||
e51546f8 KH |
5348 | /* This function is called immediately before edge E is removed from |
5349 | the edge vector E->dest->preds. */ | |
5350 | ||
5351 | static void | |
5352 | tree_execute_on_shrinking_pred (edge e) | |
5353 | { | |
5354 | if (phi_nodes (e->dest)) | |
5355 | remove_phi_args (e); | |
5356 | } | |
5357 | ||
6de9cd9a DN |
5358 | struct cfg_hooks tree_cfg_hooks = { |
5359 | "tree", | |
5360 | tree_verify_flow_info, | |
5361 | tree_dump_bb, /* dump_bb */ | |
5362 | create_bb, /* create_basic_block */ | |
5363 | tree_redirect_edge_and_branch,/* redirect_edge_and_branch */ | |
5364 | tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */ | |
5365 | remove_bb, /* delete_basic_block */ | |
5366 | tree_split_block, /* split_block */ | |
5367 | tree_move_block_after, /* move_block_after */ | |
5368 | tree_can_merge_blocks_p, /* can_merge_blocks_p */ | |
5369 | tree_merge_blocks, /* merge_blocks */ | |
5370 | tree_predict_edge, /* predict_edge */ | |
5371 | tree_predicted_by_p, /* predicted_by_p */ | |
5372 | tree_can_duplicate_bb_p, /* can_duplicate_block_p */ | |
5373 | tree_duplicate_bb, /* duplicate_block */ | |
5374 | tree_split_edge, /* split_edge */ | |
5375 | tree_make_forwarder_block, /* make_forward_block */ | |
5376 | NULL, /* tidy_fallthru_edge */ | |
5377 | tree_block_ends_with_call_p, /* block_ends_with_call_p */ | |
5378 | tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */ | |
d9d4706f | 5379 | tree_flow_call_edges_add, /* flow_call_edges_add */ |
a100ac1e | 5380 | tree_execute_on_growing_pred, /* execute_on_growing_pred */ |
e51546f8 | 5381 | tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */ |
6de9cd9a DN |
5382 | }; |
5383 | ||
5384 | ||
5385 | /* Split all critical edges. */ | |
5386 | ||
5387 | static void | |
5388 | split_critical_edges (void) | |
5389 | { | |
5390 | basic_block bb; | |
5391 | edge e; | |
628f6a4e | 5392 | edge_iterator ei; |
6de9cd9a | 5393 | |
d6be0d7f JL |
5394 | /* split_edge can redirect edges out of SWITCH_EXPRs, which can get |
5395 | expensive. So we want to enable recording of edge to CASE_LABEL_EXPR | |
5396 | mappings around the calls to split_edge. */ | |
5397 | start_recording_case_labels (); | |
6de9cd9a DN |
5398 | FOR_ALL_BB (bb) |
5399 | { | |
628f6a4e | 5400 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a DN |
5401 | if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL)) |
5402 | { | |
5403 | split_edge (e); | |
5404 | } | |
5405 | } | |
d6be0d7f | 5406 | end_recording_case_labels (); |
6de9cd9a DN |
5407 | } |
5408 | ||
5409 | struct tree_opt_pass pass_split_crit_edges = | |
5410 | { | |
5d44aeed | 5411 | "crited", /* name */ |
6de9cd9a DN |
5412 | NULL, /* gate */ |
5413 | split_critical_edges, /* execute */ | |
5414 | NULL, /* sub */ | |
5415 | NULL, /* next */ | |
5416 | 0, /* static_pass_number */ | |
5417 | TV_TREE_SPLIT_EDGES, /* tv_id */ | |
5418 | PROP_cfg, /* properties required */ | |
5419 | PROP_no_crit_edges, /* properties_provided */ | |
5420 | 0, /* properties_destroyed */ | |
5421 | 0, /* todo_flags_start */ | |
9f8628ba PB |
5422 | TODO_dump_func, /* todo_flags_finish */ |
5423 | 0 /* letter */ | |
6de9cd9a | 5424 | }; |
26277d41 PB |
5425 | |
5426 | \f | |
5427 | /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into | |
5428 | a temporary, make sure and register it to be renamed if necessary, | |
5429 | and finally return the temporary. Put the statements to compute | |
5430 | EXP before the current statement in BSI. */ | |
5431 | ||
5432 | tree | |
5433 | gimplify_val (block_stmt_iterator *bsi, tree type, tree exp) | |
5434 | { | |
5435 | tree t, new_stmt, orig_stmt; | |
5436 | ||
5437 | if (is_gimple_val (exp)) | |
5438 | return exp; | |
5439 | ||
5440 | t = make_rename_temp (type, NULL); | |
5441 | new_stmt = build (MODIFY_EXPR, type, t, exp); | |
5442 | ||
5443 | orig_stmt = bsi_stmt (*bsi); | |
5444 | SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt)); | |
5445 | TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt); | |
5446 | ||
5447 | bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT); | |
5448 | ||
5449 | return t; | |
5450 | } | |
5451 | ||
5452 | /* Build a ternary operation and gimplify it. Emit code before BSI. | |
5453 | Return the gimple_val holding the result. */ | |
5454 | ||
5455 | tree | |
5456 | gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code, | |
5457 | tree type, tree a, tree b, tree c) | |
5458 | { | |
5459 | tree ret; | |
5460 | ||
5461 | ret = fold (build3 (code, type, a, b, c)); | |
5462 | STRIP_NOPS (ret); | |
5463 | ||
5464 | return gimplify_val (bsi, type, ret); | |
5465 | } | |
5466 | ||
5467 | /* Build a binary operation and gimplify it. Emit code before BSI. | |
5468 | Return the gimple_val holding the result. */ | |
5469 | ||
5470 | tree | |
5471 | gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code, | |
5472 | tree type, tree a, tree b) | |
5473 | { | |
5474 | tree ret; | |
5475 | ||
5476 | ret = fold (build2 (code, type, a, b)); | |
5477 | STRIP_NOPS (ret); | |
5478 | ||
5479 | return gimplify_val (bsi, type, ret); | |
5480 | } | |
5481 | ||
5482 | /* Build a unary operation and gimplify it. Emit code before BSI. | |
5483 | Return the gimple_val holding the result. */ | |
5484 | ||
5485 | tree | |
5486 | gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type, | |
5487 | tree a) | |
5488 | { | |
5489 | tree ret; | |
5490 | ||
5491 | ret = fold (build1 (code, type, a)); | |
5492 | STRIP_NOPS (ret); | |
5493 | ||
5494 | return gimplify_val (bsi, type, ret); | |
5495 | } | |
5496 | ||
5497 | ||
6de9cd9a DN |
5498 | \f |
5499 | /* Emit return warnings. */ | |
5500 | ||
5501 | static void | |
5502 | execute_warn_function_return (void) | |
5503 | { | |
9506ac2b PB |
5504 | #ifdef USE_MAPPED_LOCATION |
5505 | source_location location; | |
5506 | #else | |
6de9cd9a | 5507 | location_t *locus; |
9506ac2b | 5508 | #endif |
6de9cd9a DN |
5509 | tree last; |
5510 | edge e; | |
628f6a4e | 5511 | edge_iterator ei; |
6de9cd9a DN |
5512 | |
5513 | if (warn_missing_noreturn | |
5514 | && !TREE_THIS_VOLATILE (cfun->decl) | |
628f6a4e | 5515 | && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0 |
6de9cd9a | 5516 | && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl)) |
971801ff JM |
5517 | warning ("%Jfunction might be possible candidate for " |
5518 | "attribute %<noreturn%>", | |
6de9cd9a DN |
5519 | cfun->decl); |
5520 | ||
5521 | /* If we have a path to EXIT, then we do return. */ | |
5522 | if (TREE_THIS_VOLATILE (cfun->decl) | |
628f6a4e | 5523 | && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0) |
6de9cd9a | 5524 | { |
9506ac2b PB |
5525 | #ifdef USE_MAPPED_LOCATION |
5526 | location = UNKNOWN_LOCATION; | |
5527 | #else | |
6de9cd9a | 5528 | locus = NULL; |
9506ac2b | 5529 | #endif |
628f6a4e | 5530 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds) |
6de9cd9a DN |
5531 | { |
5532 | last = last_stmt (e->src); | |
5533 | if (TREE_CODE (last) == RETURN_EXPR | |
9506ac2b PB |
5534 | #ifdef USE_MAPPED_LOCATION |
5535 | && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION) | |
5536 | #else | |
6de9cd9a | 5537 | && (locus = EXPR_LOCUS (last)) != NULL) |
9506ac2b | 5538 | #endif |
6de9cd9a DN |
5539 | break; |
5540 | } | |
9506ac2b PB |
5541 | #ifdef USE_MAPPED_LOCATION |
5542 | if (location == UNKNOWN_LOCATION) | |
5543 | location = cfun->function_end_locus; | |
971801ff | 5544 | warning ("%H%<noreturn%> function does return", &location); |
9506ac2b | 5545 | #else |
6de9cd9a DN |
5546 | if (!locus) |
5547 | locus = &cfun->function_end_locus; | |
971801ff | 5548 | warning ("%H%<noreturn%> function does return", locus); |
9506ac2b | 5549 | #endif |
6de9cd9a DN |
5550 | } |
5551 | ||
5552 | /* If we see "return;" in some basic block, then we do reach the end | |
5553 | without returning a value. */ | |
5554 | else if (warn_return_type | |
628f6a4e | 5555 | && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0 |
6de9cd9a DN |
5556 | && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl)))) |
5557 | { | |
628f6a4e | 5558 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds) |
6de9cd9a DN |
5559 | { |
5560 | tree last = last_stmt (e->src); | |
5561 | if (TREE_CODE (last) == RETURN_EXPR | |
5562 | && TREE_OPERAND (last, 0) == NULL) | |
5563 | { | |
9506ac2b PB |
5564 | #ifdef USE_MAPPED_LOCATION |
5565 | location = EXPR_LOCATION (last); | |
5566 | if (location == UNKNOWN_LOCATION) | |
5567 | location = cfun->function_end_locus; | |
5568 | warning ("%Hcontrol reaches end of non-void function", &location); | |
5569 | #else | |
6de9cd9a DN |
5570 | locus = EXPR_LOCUS (last); |
5571 | if (!locus) | |
5572 | locus = &cfun->function_end_locus; | |
5573 | warning ("%Hcontrol reaches end of non-void function", locus); | |
9506ac2b | 5574 | #endif |
6de9cd9a DN |
5575 | break; |
5576 | } | |
5577 | } | |
5578 | } | |
5579 | } | |
5580 | ||
5581 | ||
5582 | /* Given a basic block B which ends with a conditional and has | |
5583 | precisely two successors, determine which of the edges is taken if | |
5584 | the conditional is true and which is taken if the conditional is | |
5585 | false. Set TRUE_EDGE and FALSE_EDGE appropriately. */ | |
5586 | ||
5587 | void | |
5588 | extract_true_false_edges_from_block (basic_block b, | |
5589 | edge *true_edge, | |
5590 | edge *false_edge) | |
5591 | { | |
628f6a4e | 5592 | edge e = EDGE_SUCC (b, 0); |
6de9cd9a DN |
5593 | |
5594 | if (e->flags & EDGE_TRUE_VALUE) | |
5595 | { | |
5596 | *true_edge = e; | |
628f6a4e | 5597 | *false_edge = EDGE_SUCC (b, 1); |
6de9cd9a DN |
5598 | } |
5599 | else | |
5600 | { | |
5601 | *false_edge = e; | |
628f6a4e | 5602 | *true_edge = EDGE_SUCC (b, 1); |
6de9cd9a DN |
5603 | } |
5604 | } | |
5605 | ||
5606 | struct tree_opt_pass pass_warn_function_return = | |
5607 | { | |
5608 | NULL, /* name */ | |
5609 | NULL, /* gate */ | |
5610 | execute_warn_function_return, /* execute */ | |
5611 | NULL, /* sub */ | |
5612 | NULL, /* next */ | |
5613 | 0, /* static_pass_number */ | |
5614 | 0, /* tv_id */ | |
00bfee6f | 5615 | PROP_cfg, /* properties_required */ |
6de9cd9a DN |
5616 | 0, /* properties_provided */ |
5617 | 0, /* properties_destroyed */ | |
5618 | 0, /* todo_flags_start */ | |
9f8628ba PB |
5619 | 0, /* todo_flags_finish */ |
5620 | 0 /* letter */ | |
6de9cd9a DN |
5621 | }; |
5622 | ||
5623 | #include "gt-tree-cfg.h" |