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bfd49939 | 1 | /* CFG cleanup for trees. |
fbd26352 | 2 | Copyright (C) 2001-2019 Free Software Foundation, Inc. |
bfd49939 | 3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8c4c00c1 | 8 | the Free Software Foundation; either version 3, or (at your option) |
bfd49939 | 9 | any later version. |
10 | ||
11 | GCC is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
8c4c00c1 | 17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
bfd49939 | 19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "coretypes.h" | |
9ef16211 | 23 | #include "backend.h" |
7c29e30e | 24 | #include "rtl.h" |
bfd49939 | 25 | #include "tree.h" |
9ef16211 | 26 | #include "gimple.h" |
7c29e30e | 27 | #include "cfghooks.h" |
28 | #include "tree-pass.h" | |
9ef16211 | 29 | #include "ssa.h" |
7c29e30e | 30 | #include "diagnostic-core.h" |
b20a8bb4 | 31 | #include "fold-const.h" |
94ea8568 | 32 | #include "cfganal.h" |
33 | #include "cfgcleanup.h" | |
bc61cadb | 34 | #include "tree-eh.h" |
a8783bee | 35 | #include "gimplify.h" |
dcf1a1ec | 36 | #include "gimple-iterator.h" |
073c1fd5 | 37 | #include "tree-cfg.h" |
05d9c18a | 38 | #include "tree-ssa-loop-manip.h" |
073c1fd5 | 39 | #include "tree-dfa.h" |
69ee5dbb | 40 | #include "tree-ssa.h" |
bfd49939 | 41 | #include "cfgloop.h" |
b30560de | 42 | #include "tree-scalar-evolution.h" |
04a37b12 | 43 | #include "gimple-match.h" |
44 | #include "gimple-fold.h" | |
ffeccaca | 45 | #include "tree-ssa-loop-niter.h" |
9eafff7e | 46 | #include "cgraph.h" |
d7419e5b | 47 | #include "tree-into-ssa.h" |
48 | #include "tree-cfgcleanup.h" | |
49 | ||
bfd49939 | 50 | |
31a8456e | 51 | /* The set of blocks in that at least one of the following changes happened: |
52 | -- the statement at the end of the block was changed | |
53 | -- the block was newly created | |
54 | -- the set of the predecessors of the block changed | |
55 | -- the set of the successors of the block changed | |
56 | ??? Maybe we could track these changes separately, since they determine | |
57 | what cleanups it makes sense to try on the block. */ | |
58 | bitmap cfgcleanup_altered_bbs; | |
59 | ||
bfd49939 | 60 | /* Remove any fallthru edge from EV. Return true if an edge was removed. */ |
61 | ||
62 | static bool | |
f1f41a6c | 63 | remove_fallthru_edge (vec<edge, va_gc> *ev) |
bfd49939 | 64 | { |
65 | edge_iterator ei; | |
66 | edge e; | |
67 | ||
68 | FOR_EACH_EDGE (e, ei, ev) | |
69 | if ((e->flags & EDGE_FALLTHRU) != 0) | |
70 | { | |
e2a6b9da | 71 | if (e->flags & EDGE_COMPLEX) |
72 | e->flags &= ~EDGE_FALLTHRU; | |
73 | else | |
74 | remove_edge_and_dominated_blocks (e); | |
bfd49939 | 75 | return true; |
76 | } | |
77 | return false; | |
78 | } | |
79 | ||
baab4554 | 80 | /* Convert a SWTCH with single non-default case to gcond and replace it |
81 | at GSI. */ | |
82 | ||
83 | static bool | |
84 | convert_single_case_switch (gswitch *swtch, gimple_stmt_iterator &gsi) | |
85 | { | |
86 | if (gimple_switch_num_labels (swtch) != 2) | |
87 | return false; | |
88 | ||
89 | tree index = gimple_switch_index (swtch); | |
baab4554 | 90 | tree label = gimple_switch_label (swtch, 1); |
91 | tree low = CASE_LOW (label); | |
92 | tree high = CASE_HIGH (label); | |
93 | ||
0fb4f2ce | 94 | basic_block default_bb = gimple_switch_default_bb (cfun, swtch); |
95 | basic_block case_bb = label_to_block (cfun, CASE_LABEL (label)); | |
baab4554 | 96 | |
97 | basic_block bb = gimple_bb (swtch); | |
98 | gcond *cond; | |
99 | ||
100 | /* Replace switch statement with condition statement. */ | |
101 | if (high) | |
102 | { | |
103 | tree lhs, rhs; | |
104 | generate_range_test (bb, index, low, high, &lhs, &rhs); | |
105 | cond = gimple_build_cond (LE_EXPR, lhs, rhs, NULL_TREE, NULL_TREE); | |
106 | } | |
107 | else | |
108 | cond = gimple_build_cond (EQ_EXPR, index, | |
109 | fold_convert (TREE_TYPE (index), low), | |
110 | NULL_TREE, NULL_TREE); | |
111 | ||
112 | gsi_replace (&gsi, cond, true); | |
113 | ||
114 | /* Update edges. */ | |
115 | edge case_edge = find_edge (bb, case_bb); | |
116 | edge default_edge = find_edge (bb, default_bb); | |
117 | ||
118 | case_edge->flags |= EDGE_TRUE_VALUE; | |
119 | default_edge->flags |= EDGE_FALSE_VALUE; | |
120 | return true; | |
121 | } | |
75a70cf9 | 122 | |
bfd49939 | 123 | /* Disconnect an unreachable block in the control expression starting |
124 | at block BB. */ | |
125 | ||
126 | static bool | |
53fe6e2f | 127 | cleanup_control_expr_graph (basic_block bb, gimple_stmt_iterator gsi) |
bfd49939 | 128 | { |
129 | edge taken_edge; | |
130 | bool retval = false; | |
42acab1c | 131 | gimple *stmt = gsi_stmt (gsi); |
bfd49939 | 132 | |
133 | if (!single_succ_p (bb)) | |
134 | { | |
135 | edge e; | |
136 | edge_iterator ei; | |
add6ee5e | 137 | bool warned; |
04a37b12 | 138 | tree val = NULL_TREE; |
add6ee5e | 139 | |
baab4554 | 140 | /* Try to convert a switch with just a single non-default case to |
141 | GIMPLE condition. */ | |
142 | if (gimple_code (stmt) == GIMPLE_SWITCH | |
143 | && convert_single_case_switch (as_a<gswitch *> (stmt), gsi)) | |
144 | stmt = gsi_stmt (gsi); | |
145 | ||
add6ee5e | 146 | fold_defer_overflow_warnings (); |
db2cc26b | 147 | switch (gimple_code (stmt)) |
148 | { | |
149 | case GIMPLE_COND: | |
53fe6e2f | 150 | { |
49446baa | 151 | gimple_match_op res_op; |
152 | if (gimple_simplify (stmt, &res_op, NULL, no_follow_ssa_edges, | |
53fe6e2f | 153 | no_follow_ssa_edges) |
49446baa | 154 | && res_op.code == INTEGER_CST) |
155 | val = res_op.ops[0]; | |
53fe6e2f | 156 | } |
b5e7cd42 | 157 | break; |
db2cc26b | 158 | |
159 | case GIMPLE_SWITCH: | |
1a91d914 | 160 | val = gimple_switch_index (as_a <gswitch *> (stmt)); |
db2cc26b | 161 | break; |
162 | ||
163 | default: | |
04a37b12 | 164 | ; |
db2cc26b | 165 | } |
bfd49939 | 166 | taken_edge = find_taken_edge (bb, val); |
167 | if (!taken_edge) | |
add6ee5e | 168 | { |
169 | fold_undefer_and_ignore_overflow_warnings (); | |
170 | return false; | |
171 | } | |
bfd49939 | 172 | |
173 | /* Remove all the edges except the one that is always executed. */ | |
add6ee5e | 174 | warned = false; |
bfd49939 | 175 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) |
176 | { | |
177 | if (e != taken_edge) | |
178 | { | |
add6ee5e | 179 | if (!warned) |
180 | { | |
181 | fold_undefer_overflow_warnings | |
75a70cf9 | 182 | (true, stmt, WARN_STRICT_OVERFLOW_CONDITIONAL); |
add6ee5e | 183 | warned = true; |
184 | } | |
185 | ||
bfd49939 | 186 | taken_edge->probability += e->probability; |
31a8456e | 187 | remove_edge_and_dominated_blocks (e); |
bfd49939 | 188 | retval = true; |
189 | } | |
190 | else | |
191 | ei_next (&ei); | |
192 | } | |
add6ee5e | 193 | if (!warned) |
194 | fold_undefer_and_ignore_overflow_warnings (); | |
bfd49939 | 195 | } |
196 | else | |
197 | taken_edge = single_succ_edge (bb); | |
198 | ||
31a8456e | 199 | bitmap_set_bit (cfgcleanup_altered_bbs, bb->index); |
75a70cf9 | 200 | gsi_remove (&gsi, true); |
bfd49939 | 201 | taken_edge->flags = EDGE_FALLTHRU; |
202 | ||
bfd49939 | 203 | return retval; |
204 | } | |
205 | ||
c1e02247 | 206 | /* Cleanup the GF_CALL_CTRL_ALTERING flag according to |
207 | to updated gimple_call_flags. */ | |
208 | ||
209 | static void | |
42acab1c | 210 | cleanup_call_ctrl_altering_flag (gimple *bb_end) |
c1e02247 | 211 | { |
212 | if (!is_gimple_call (bb_end) | |
213 | || !gimple_call_ctrl_altering_p (bb_end)) | |
214 | return; | |
215 | ||
216 | int flags = gimple_call_flags (bb_end); | |
217 | if (((flags & (ECF_CONST | ECF_PURE)) | |
218 | && !(flags & ECF_LOOPING_CONST_OR_PURE)) | |
219 | || (flags & ECF_LEAF)) | |
220 | gimple_call_set_ctrl_altering (bb_end, false); | |
221 | } | |
222 | ||
31a8456e | 223 | /* Try to remove superfluous control structures in basic block BB. Returns |
224 | true if anything changes. */ | |
bfd49939 | 225 | |
226 | static bool | |
53fe6e2f | 227 | cleanup_control_flow_bb (basic_block bb) |
bfd49939 | 228 | { |
75a70cf9 | 229 | gimple_stmt_iterator gsi; |
bfd49939 | 230 | bool retval = false; |
42acab1c | 231 | gimple *stmt; |
bfd49939 | 232 | |
31a8456e | 233 | /* If the last statement of the block could throw and now cannot, |
234 | we need to prune cfg. */ | |
75a70cf9 | 235 | retval |= gimple_purge_dead_eh_edges (bb); |
31a8456e | 236 | |
1f531aaf | 237 | gsi = gsi_last_nondebug_bb (bb); |
75a70cf9 | 238 | if (gsi_end_p (gsi)) |
31a8456e | 239 | return retval; |
240 | ||
75a70cf9 | 241 | stmt = gsi_stmt (gsi); |
31a8456e | 242 | |
c1e02247 | 243 | /* Try to cleanup ctrl altering flag for call which ends bb. */ |
244 | cleanup_call_ctrl_altering_flag (stmt); | |
245 | ||
75a70cf9 | 246 | if (gimple_code (stmt) == GIMPLE_COND |
247 | || gimple_code (stmt) == GIMPLE_SWITCH) | |
1f531aaf | 248 | { |
249 | gcc_checking_assert (gsi_stmt (gsi_last_bb (bb)) == stmt); | |
53fe6e2f | 250 | retval |= cleanup_control_expr_graph (bb, gsi); |
1f531aaf | 251 | } |
75a70cf9 | 252 | else if (gimple_code (stmt) == GIMPLE_GOTO |
253 | && TREE_CODE (gimple_goto_dest (stmt)) == ADDR_EXPR | |
254 | && (TREE_CODE (TREE_OPERAND (gimple_goto_dest (stmt), 0)) | |
31a8456e | 255 | == LABEL_DECL)) |
bfd49939 | 256 | { |
75a70cf9 | 257 | /* If we had a computed goto which has a compile-time determinable |
258 | destination, then we can eliminate the goto. */ | |
31a8456e | 259 | edge e; |
260 | tree label; | |
261 | edge_iterator ei; | |
262 | basic_block target_block; | |
bfd49939 | 263 | |
1f531aaf | 264 | gcc_checking_assert (gsi_stmt (gsi_last_bb (bb)) == stmt); |
31a8456e | 265 | /* First look at all the outgoing edges. Delete any outgoing |
266 | edges which do not go to the right block. For the one | |
267 | edge which goes to the right block, fix up its flags. */ | |
75a70cf9 | 268 | label = TREE_OPERAND (gimple_goto_dest (stmt), 0); |
68148367 | 269 | if (DECL_CONTEXT (label) != cfun->decl) |
270 | return retval; | |
0fb4f2ce | 271 | target_block = label_to_block (cfun, label); |
31a8456e | 272 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) |
bfd49939 | 273 | { |
31a8456e | 274 | if (e->dest != target_block) |
275 | remove_edge_and_dominated_blocks (e); | |
276 | else | |
bfd49939 | 277 | { |
31a8456e | 278 | /* Turn off the EDGE_ABNORMAL flag. */ |
279 | e->flags &= ~EDGE_ABNORMAL; | |
bfd49939 | 280 | |
31a8456e | 281 | /* And set EDGE_FALLTHRU. */ |
282 | e->flags |= EDGE_FALLTHRU; | |
283 | ei_next (&ei); | |
284 | } | |
bfd49939 | 285 | } |
286 | ||
31a8456e | 287 | bitmap_set_bit (cfgcleanup_altered_bbs, bb->index); |
288 | bitmap_set_bit (cfgcleanup_altered_bbs, target_block->index); | |
289 | ||
290 | /* Remove the GOTO_EXPR as it is not needed. The CFG has all the | |
291 | relevant information we need. */ | |
75a70cf9 | 292 | gsi_remove (&gsi, true); |
31a8456e | 293 | retval = true; |
bfd49939 | 294 | } |
31a8456e | 295 | |
296 | /* Check for indirect calls that have been turned into | |
297 | noreturn calls. */ | |
75a70cf9 | 298 | else if (is_gimple_call (stmt) |
1f531aaf | 299 | && gimple_call_noreturn_p (stmt)) |
300 | { | |
301 | /* If there are debug stmts after the noreturn call, remove them | |
302 | now, they should be all unreachable anyway. */ | |
303 | for (gsi_next (&gsi); !gsi_end_p (gsi); ) | |
304 | gsi_remove (&gsi, true); | |
305 | if (remove_fallthru_edge (bb->succs)) | |
306 | retval = true; | |
307 | } | |
31a8456e | 308 | |
bfd49939 | 309 | return retval; |
310 | } | |
311 | ||
312 | /* Return true if basic block BB does nothing except pass control | |
313 | flow to another block and that we can safely insert a label at | |
314 | the start of the successor block. | |
315 | ||
316 | As a precondition, we require that BB be not equal to | |
efee62d1 | 317 | the entry block. */ |
bfd49939 | 318 | |
319 | static bool | |
320 | tree_forwarder_block_p (basic_block bb, bool phi_wanted) | |
321 | { | |
75a70cf9 | 322 | gimple_stmt_iterator gsi; |
65138c0f | 323 | location_t locus; |
bfd49939 | 324 | |
325 | /* BB must have a single outgoing edge. */ | |
326 | if (single_succ_p (bb) != 1 | |
327 | /* If PHI_WANTED is false, BB must not have any PHI nodes. | |
328 | Otherwise, BB must have PHI nodes. */ | |
75a70cf9 | 329 | || gimple_seq_empty_p (phi_nodes (bb)) == phi_wanted |
efee62d1 | 330 | /* BB may not be a predecessor of the exit block. */ |
34154e27 | 331 | || single_succ (bb) == EXIT_BLOCK_PTR_FOR_FN (cfun) |
bfd49939 | 332 | /* Nor should this be an infinite loop. */ |
333 | || single_succ (bb) == bb | |
334 | /* BB may not have an abnormal outgoing edge. */ | |
335 | || (single_succ_edge (bb)->flags & EDGE_ABNORMAL)) | |
336 | return false; | |
337 | ||
34154e27 | 338 | gcc_checking_assert (bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
bfd49939 | 339 | |
65138c0f | 340 | locus = single_succ_edge (bb)->goto_locus; |
341 | ||
e38def9c | 342 | /* There should not be an edge coming from entry, or an EH edge. */ |
343 | { | |
344 | edge_iterator ei; | |
345 | edge e; | |
346 | ||
347 | FOR_EACH_EDGE (e, ei, bb->preds) | |
34154e27 | 348 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun) || (e->flags & EDGE_EH)) |
e38def9c | 349 | return false; |
65138c0f | 350 | /* If goto_locus of any of the edges differs, prevent removing |
06a8367a | 351 | the forwarder block when not optimizing. */ |
352 | else if (!optimize | |
353 | && (LOCATION_LOCUS (e->goto_locus) != UNKNOWN_LOCATION | |
354 | || LOCATION_LOCUS (locus) != UNKNOWN_LOCATION) | |
355 | && e->goto_locus != locus) | |
65138c0f | 356 | return false; |
e38def9c | 357 | } |
358 | ||
bfd49939 | 359 | /* Now walk through the statements backward. We can ignore labels, |
360 | anything else means this is not a forwarder block. */ | |
75a70cf9 | 361 | for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi)) |
bfd49939 | 362 | { |
42acab1c | 363 | gimple *stmt = gsi_stmt (gsi); |
bfd49939 | 364 | |
75a70cf9 | 365 | switch (gimple_code (stmt)) |
bfd49939 | 366 | { |
75a70cf9 | 367 | case GIMPLE_LABEL: |
1a91d914 | 368 | if (DECL_NONLOCAL (gimple_label_label (as_a <glabel *> (stmt)))) |
bfd49939 | 369 | return false; |
06a8367a | 370 | if (!optimize |
371 | && (gimple_has_location (stmt) | |
372 | || LOCATION_LOCUS (locus) != UNKNOWN_LOCATION) | |
373 | && gimple_location (stmt) != locus) | |
65138c0f | 374 | return false; |
bfd49939 | 375 | break; |
376 | ||
9845d120 | 377 | /* ??? For now, hope there's a corresponding debug |
378 | assignment at the destination. */ | |
379 | case GIMPLE_DEBUG: | |
380 | break; | |
381 | ||
bfd49939 | 382 | default: |
383 | return false; | |
384 | } | |
385 | } | |
386 | ||
bfd49939 | 387 | if (current_loops) |
388 | { | |
389 | basic_block dest; | |
3c2e3ed6 | 390 | /* Protect loop headers. */ |
d7407ea0 | 391 | if (bb_loop_header_p (bb)) |
bfd49939 | 392 | return false; |
bfd49939 | 393 | |
3c2e3ed6 | 394 | dest = EDGE_SUCC (bb, 0)->dest; |
395 | /* Protect loop preheaders and latches if requested. */ | |
bfd49939 | 396 | if (dest->loop_father->header == dest) |
3c2e3ed6 | 397 | { |
0ab3f603 | 398 | if (bb->loop_father == dest->loop_father) |
399 | { | |
400 | if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) | |
401 | return false; | |
402 | /* If bb doesn't have a single predecessor we'd make this | |
403 | loop have multiple latches. Don't do that if that | |
404 | would in turn require disambiguating them. */ | |
405 | return (single_pred_p (bb) | |
406 | || loops_state_satisfies_p | |
407 | (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)); | |
408 | } | |
409 | else if (bb->loop_father == loop_outer (dest->loop_father)) | |
410 | return !loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS); | |
411 | /* Always preserve other edges into loop headers that are | |
412 | not simple latches or preheaders. */ | |
413 | return false; | |
3c2e3ed6 | 414 | } |
bfd49939 | 415 | } |
3c2e3ed6 | 416 | |
bfd49939 | 417 | return true; |
418 | } | |
419 | ||
bfd49939 | 420 | /* If all the PHI nodes in DEST have alternatives for E1 and E2 and |
421 | those alternatives are equal in each of the PHI nodes, then return | |
422 | true, else return false. */ | |
423 | ||
424 | static bool | |
425 | phi_alternatives_equal (basic_block dest, edge e1, edge e2) | |
426 | { | |
427 | int n1 = e1->dest_idx; | |
428 | int n2 = e2->dest_idx; | |
1a91d914 | 429 | gphi_iterator gsi; |
bfd49939 | 430 | |
75a70cf9 | 431 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
bfd49939 | 432 | { |
1a91d914 | 433 | gphi *phi = gsi.phi (); |
75a70cf9 | 434 | tree val1 = gimple_phi_arg_def (phi, n1); |
435 | tree val2 = gimple_phi_arg_def (phi, n2); | |
bfd49939 | 436 | |
437 | gcc_assert (val1 != NULL_TREE); | |
438 | gcc_assert (val2 != NULL_TREE); | |
439 | ||
440 | if (!operand_equal_for_phi_arg_p (val1, val2)) | |
441 | return false; | |
442 | } | |
443 | ||
444 | return true; | |
445 | } | |
446 | ||
a894735c | 447 | /* Move debug stmts from the forwarder block SRC to DEST. */ |
448 | ||
449 | static void | |
52455dd5 | 450 | move_debug_stmts_from_forwarder (basic_block src, basic_block dest, |
451 | bool dest_single_pred_p) | |
a894735c | 452 | { |
453 | if (!MAY_HAVE_DEBUG_STMTS) | |
454 | return; | |
455 | ||
a894735c | 456 | gimple_stmt_iterator gsi_to = gsi_after_labels (dest); |
457 | for (gimple_stmt_iterator gsi = gsi_after_labels (src); !gsi_end_p (gsi);) | |
458 | { | |
459 | gimple *debug = gsi_stmt (gsi); | |
460 | gcc_assert (is_gimple_debug (debug)); | |
461 | /* Move debug binds anyway, but not anything else like begin-stmt | |
462 | markers unless they are always valid at the destination. */ | |
52455dd5 | 463 | if (dest_single_pred_p |
a894735c | 464 | || gimple_debug_bind_p (debug)) |
465 | { | |
466 | gsi_move_before (&gsi, &gsi_to); | |
467 | /* Reset debug-binds that are not always valid at the destination. | |
468 | Simply dropping them can cause earlier values to become live, | |
469 | generating wrong debug information. | |
470 | ??? There are several things we could improve here. For | |
471 | one we might be able to move stmts to the predecessor. | |
472 | For anther, if the debug stmt is immediately followed by a | |
473 | (debug) definition in the destination (on a post-dominated path?) | |
474 | we can elide it without any bad effects. */ | |
52455dd5 | 475 | if (!dest_single_pred_p) |
a894735c | 476 | { |
477 | gimple_debug_bind_reset_value (debug); | |
478 | update_stmt (debug); | |
479 | } | |
480 | } | |
481 | else | |
482 | gsi_next (&gsi); | |
483 | } | |
484 | } | |
485 | ||
31a8456e | 486 | /* Removes forwarder block BB. Returns false if this failed. */ |
bfd49939 | 487 | |
488 | static bool | |
31a8456e | 489 | remove_forwarder_block (basic_block bb) |
bfd49939 | 490 | { |
491 | edge succ = single_succ_edge (bb), e, s; | |
492 | basic_block dest = succ->dest; | |
d71c7316 | 493 | gimple *stmt; |
bfd49939 | 494 | edge_iterator ei; |
75a70cf9 | 495 | gimple_stmt_iterator gsi, gsi_to; |
bfd49939 | 496 | |
497 | /* We check for infinite loops already in tree_forwarder_block_p. | |
498 | However it may happen that the infinite loop is created | |
499 | afterwards due to removal of forwarders. */ | |
500 | if (dest == bb) | |
501 | return false; | |
502 | ||
11d28f28 | 503 | /* If the destination block consists of a nonlocal label or is a |
504 | EH landing pad, do not merge it. */ | |
d71c7316 | 505 | stmt = first_stmt (dest); |
506 | if (stmt) | |
507 | if (glabel *label_stmt = dyn_cast <glabel *> (stmt)) | |
1a91d914 | 508 | if (DECL_NONLOCAL (gimple_label_label (label_stmt)) |
509 | || EH_LANDING_PAD_NR (gimple_label_label (label_stmt)) != 0) | |
510 | return false; | |
bfd49939 | 511 | |
512 | /* If there is an abnormal edge to basic block BB, but not into | |
513 | dest, problems might occur during removal of the phi node at out | |
514 | of ssa due to overlapping live ranges of registers. | |
515 | ||
516 | If there is an abnormal edge in DEST, the problems would occur | |
517 | anyway since cleanup_dead_labels would then merge the labels for | |
518 | two different eh regions, and rest of exception handling code | |
519 | does not like it. | |
520 | ||
521 | So if there is an abnormal edge to BB, proceed only if there is | |
522 | no abnormal edge to DEST and there are no phi nodes in DEST. */ | |
f1047120 | 523 | if (bb_has_abnormal_pred (bb) |
524 | && (bb_has_abnormal_pred (dest) | |
7b960d37 | 525 | || !gimple_seq_empty_p (phi_nodes (dest)))) |
526 | return false; | |
bfd49939 | 527 | |
528 | /* If there are phi nodes in DEST, and some of the blocks that are | |
529 | predecessors of BB are also predecessors of DEST, check that the | |
530 | phi node arguments match. */ | |
75a70cf9 | 531 | if (!gimple_seq_empty_p (phi_nodes (dest))) |
bfd49939 | 532 | { |
533 | FOR_EACH_EDGE (e, ei, bb->preds) | |
534 | { | |
535 | s = find_edge (e->src, dest); | |
536 | if (!s) | |
537 | continue; | |
538 | ||
539 | if (!phi_alternatives_equal (dest, succ, s)) | |
540 | return false; | |
541 | } | |
542 | } | |
543 | ||
0ab3f603 | 544 | basic_block pred = NULL; |
545 | if (single_pred_p (bb)) | |
546 | pred = single_pred (bb); | |
52455dd5 | 547 | bool dest_single_pred_p = single_pred_p (dest); |
0ab3f603 | 548 | |
bfd49939 | 549 | /* Redirect the edges. */ |
550 | for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) | |
551 | { | |
31a8456e | 552 | bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index); |
553 | ||
bfd49939 | 554 | if (e->flags & EDGE_ABNORMAL) |
555 | { | |
556 | /* If there is an abnormal edge, redirect it anyway, and | |
557 | move the labels to the new block to make it legal. */ | |
558 | s = redirect_edge_succ_nodup (e, dest); | |
559 | } | |
560 | else | |
561 | s = redirect_edge_and_branch (e, dest); | |
562 | ||
563 | if (s == e) | |
564 | { | |
565 | /* Create arguments for the phi nodes, since the edge was not | |
566 | here before. */ | |
1a91d914 | 567 | for (gphi_iterator psi = gsi_start_phis (dest); |
568 | !gsi_end_p (psi); | |
569 | gsi_next (&psi)) | |
75a70cf9 | 570 | { |
1a91d914 | 571 | gphi *phi = psi.phi (); |
be1e7283 | 572 | location_t l = gimple_phi_arg_location_from_edge (phi, succ); |
11db727d | 573 | tree def = gimple_phi_arg_def (phi, succ->dest_idx); |
574 | add_phi_arg (phi, unshare_expr (def), s, l); | |
75a70cf9 | 575 | } |
bfd49939 | 576 | } |
bfd49939 | 577 | } |
578 | ||
7b960d37 | 579 | /* Move nonlocal labels and computed goto targets as well as user |
580 | defined labels and labels with an EH landing pad number to the | |
581 | new block, so that the redirection of the abnormal edges works, | |
582 | jump targets end up in a sane place and debug information for | |
d71c7316 | 583 | labels is retained. */ |
7b960d37 | 584 | gsi_to = gsi_start_bb (dest); |
d71c7316 | 585 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) |
7b960d37 | 586 | { |
d71c7316 | 587 | stmt = gsi_stmt (gsi); |
588 | if (is_gimple_debug (stmt)) | |
589 | break; | |
590 | ||
591 | /* Forwarder blocks can only contain labels and debug stmts, and | |
592 | labels must come first, so if we get to this point, we know | |
593 | we're looking at a label. */ | |
594 | tree decl = gimple_label_label (as_a <glabel *> (stmt)); | |
595 | if (EH_LANDING_PAD_NR (decl) != 0 | |
596 | || DECL_NONLOCAL (decl) | |
597 | || FORCED_LABEL (decl) | |
598 | || !DECL_ARTIFICIAL (decl)) | |
599 | gsi_move_before (&gsi, &gsi_to); | |
7b960d37 | 600 | else |
601 | gsi_next (&gsi); | |
602 | } | |
603 | ||
82e79b5e | 604 | /* Move debug statements. Reset them if the destination does not |
605 | have a single predecessor. */ | |
52455dd5 | 606 | move_debug_stmts_from_forwarder (bb, dest, dest_single_pred_p); |
5c4c939c | 607 | |
31a8456e | 608 | bitmap_set_bit (cfgcleanup_altered_bbs, dest->index); |
609 | ||
bfd49939 | 610 | /* Update the dominators. */ |
611 | if (dom_info_available_p (CDI_DOMINATORS)) | |
612 | { | |
613 | basic_block dom, dombb, domdest; | |
614 | ||
615 | dombb = get_immediate_dominator (CDI_DOMINATORS, bb); | |
616 | domdest = get_immediate_dominator (CDI_DOMINATORS, dest); | |
617 | if (domdest == bb) | |
618 | { | |
619 | /* Shortcut to avoid calling (relatively expensive) | |
620 | nearest_common_dominator unless necessary. */ | |
621 | dom = dombb; | |
622 | } | |
623 | else | |
624 | dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb); | |
625 | ||
626 | set_immediate_dominator (CDI_DOMINATORS, dest, dom); | |
627 | } | |
628 | ||
3c2e3ed6 | 629 | /* Adjust latch infomation of BB's parent loop as otherwise |
630 | the cfg hook has a hard time not to kill the loop. */ | |
631 | if (current_loops && bb->loop_father->latch == bb) | |
0ab3f603 | 632 | bb->loop_father->latch = pred; |
3c2e3ed6 | 633 | |
bfd49939 | 634 | /* And kill the forwarder block. */ |
635 | delete_basic_block (bb); | |
636 | ||
637 | return true; | |
638 | } | |
639 | ||
305d4389 | 640 | /* STMT is a call that has been discovered noreturn. Split the |
641 | block to prepare fixing up the CFG and remove LHS. | |
642 | Return true if cleanup-cfg needs to run. */ | |
3b4fe440 | 643 | |
644 | bool | |
42acab1c | 645 | fixup_noreturn_call (gimple *stmt) |
3b4fe440 | 646 | { |
647 | basic_block bb = gimple_bb (stmt); | |
305d4389 | 648 | bool changed = false; |
3b4fe440 | 649 | |
650 | if (gimple_call_builtin_p (stmt, BUILT_IN_RETURN)) | |
651 | return false; | |
652 | ||
653 | /* First split basic block if stmt is not last. */ | |
654 | if (stmt != gsi_stmt (gsi_last_bb (bb))) | |
4e9d7164 | 655 | { |
656 | if (stmt == gsi_stmt (gsi_last_nondebug_bb (bb))) | |
657 | { | |
658 | /* Don't split if there are only debug stmts | |
659 | after stmt, that can result in -fcompare-debug | |
660 | failures. Remove the debug stmts instead, | |
661 | they should be all unreachable anyway. */ | |
662 | gimple_stmt_iterator gsi = gsi_for_stmt (stmt); | |
663 | for (gsi_next (&gsi); !gsi_end_p (gsi); ) | |
664 | gsi_remove (&gsi, true); | |
665 | } | |
666 | else | |
305d4389 | 667 | { |
668 | split_block (bb, stmt); | |
669 | changed = true; | |
670 | } | |
4e9d7164 | 671 | } |
3b4fe440 | 672 | |
33b2642e | 673 | /* If there is an LHS, remove it, but only if its type has fixed size. |
674 | The LHS will need to be recreated during RTL expansion and creating | |
1fe75cf2 | 675 | temporaries of variable-sized types is not supported. Also don't |
c4994c0b | 676 | do this with TREE_ADDRESSABLE types, as assign_temp will abort. |
677 | Drop LHS regardless of TREE_ADDRESSABLE, if the function call | |
678 | has been changed into a call that does not return a value, like | |
679 | __builtin_unreachable or __cxa_pure_virtual. */ | |
6d6c8aba | 680 | tree lhs = gimple_call_lhs (stmt); |
c4994c0b | 681 | if (lhs |
682 | && (should_remove_lhs_p (lhs) | |
683 | || VOID_TYPE_P (TREE_TYPE (gimple_call_fntype (stmt))))) | |
3b4fe440 | 684 | { |
3b4fe440 | 685 | gimple_call_set_lhs (stmt, NULL_TREE); |
b703d146 | 686 | |
6d6c8aba | 687 | /* We need to fix up the SSA name to avoid checking errors. */ |
688 | if (TREE_CODE (lhs) == SSA_NAME) | |
3b4fe440 | 689 | { |
f9e245b2 | 690 | tree new_var = create_tmp_reg (TREE_TYPE (lhs)); |
6d6c8aba | 691 | SET_SSA_NAME_VAR_OR_IDENTIFIER (lhs, new_var); |
692 | SSA_NAME_DEF_STMT (lhs) = gimple_build_nop (); | |
693 | set_ssa_default_def (cfun, new_var, lhs); | |
3b4fe440 | 694 | } |
6d6c8aba | 695 | |
3b4fe440 | 696 | update_stmt (stmt); |
3b4fe440 | 697 | } |
6d6c8aba | 698 | |
25959a39 | 699 | /* Mark the call as altering control flow. */ |
305d4389 | 700 | if (!gimple_call_ctrl_altering_p (stmt)) |
701 | { | |
702 | gimple_call_set_ctrl_altering (stmt, true); | |
703 | changed = true; | |
704 | } | |
25959a39 | 705 | |
305d4389 | 706 | return changed; |
3b4fe440 | 707 | } |
708 | ||
4669b904 | 709 | /* Return true if we want to merge BB1 and BB2 into a single block. */ |
710 | ||
711 | static bool | |
712 | want_merge_blocks_p (basic_block bb1, basic_block bb2) | |
713 | { | |
714 | if (!can_merge_blocks_p (bb1, bb2)) | |
715 | return false; | |
716 | gimple_stmt_iterator gsi = gsi_last_nondebug_bb (bb1); | |
717 | if (gsi_end_p (gsi) || !stmt_can_terminate_bb_p (gsi_stmt (gsi))) | |
718 | return true; | |
719 | return bb1->count.ok_for_merging (bb2->count); | |
720 | } | |
721 | ||
3b4fe440 | 722 | |
11f5525b | 723 | /* Tries to cleanup cfg in basic block BB by merging blocks. Returns |
724 | true if anything changes. */ | |
bfd49939 | 725 | |
0c6b4703 | 726 | static bool |
31a8456e | 727 | cleanup_tree_cfg_bb (basic_block bb) |
bfd49939 | 728 | { |
65138c0f | 729 | if (tree_forwarder_block_p (bb, false) |
31a8456e | 730 | && remove_forwarder_block (bb)) |
731 | return true; | |
bfd49939 | 732 | |
c162fa25 | 733 | /* If there is a merge opportunity with the predecessor |
734 | do nothing now but wait until we process the predecessor. | |
735 | This happens when we visit BBs in a non-optimal order and | |
736 | avoids quadratic behavior with adjusting stmts BB pointer. */ | |
737 | if (single_pred_p (bb) | |
4669b904 | 738 | && want_merge_blocks_p (single_pred (bb), bb)) |
c162fa25 | 739 | /* But make sure we _do_ visit it. When we remove unreachable paths |
740 | ending in a backedge we fail to mark the destinations predecessors | |
741 | as changed. */ | |
742 | bitmap_set_bit (cfgcleanup_altered_bbs, single_pred (bb)->index); | |
743 | ||
0c6b4703 | 744 | /* Merging the blocks may create new opportunities for folding |
745 | conditional branches (due to the elimination of single-valued PHI | |
746 | nodes). */ | |
c162fa25 | 747 | else if (single_succ_p (bb) |
4669b904 | 748 | && want_merge_blocks_p (bb, single_succ (bb))) |
31a8456e | 749 | { |
c162fa25 | 750 | merge_blocks (bb, single_succ (bb)); |
751 | return true; | |
31a8456e | 752 | } |
753 | ||
5a0e130a | 754 | return false; |
31a8456e | 755 | } |
756 | ||
400c29ff | 757 | /* Return true if E is an EDGE_ABNORMAL edge for returns_twice calls, |
758 | i.e. one going from .ABNORMAL_DISPATCHER to basic block which doesn't | |
759 | start with a forced or nonlocal label. Calls which return twice can return | |
760 | the second time only if they are called normally the first time, so basic | |
761 | blocks which can be only entered through these abnormal edges but not | |
762 | normally are effectively unreachable as well. Additionally ignore | |
763 | __builtin_setjmp_receiver starting blocks, which have one FORCED_LABEL | |
764 | and which are always only reachable through EDGE_ABNORMAL edge. They are | |
765 | handled in cleanup_control_flow_pre. */ | |
766 | ||
767 | static bool | |
768 | maybe_dead_abnormal_edge_p (edge e) | |
769 | { | |
770 | if ((e->flags & (EDGE_ABNORMAL | EDGE_EH)) != EDGE_ABNORMAL) | |
771 | return false; | |
772 | ||
773 | gimple_stmt_iterator gsi = gsi_start_nondebug_after_labels_bb (e->src); | |
774 | gimple *g = gsi_stmt (gsi); | |
775 | if (!g || !gimple_call_internal_p (g, IFN_ABNORMAL_DISPATCHER)) | |
776 | return false; | |
777 | ||
778 | tree target = NULL_TREE; | |
779 | for (gsi = gsi_start_bb (e->dest); !gsi_end_p (gsi); gsi_next (&gsi)) | |
780 | if (glabel *label_stmt = dyn_cast <glabel *> (gsi_stmt (gsi))) | |
781 | { | |
782 | tree this_target = gimple_label_label (label_stmt); | |
783 | if (DECL_NONLOCAL (this_target)) | |
784 | return false; | |
785 | if (FORCED_LABEL (this_target)) | |
786 | { | |
787 | if (target) | |
788 | return false; | |
789 | target = this_target; | |
790 | } | |
791 | } | |
792 | else | |
793 | break; | |
794 | ||
795 | if (target) | |
796 | { | |
797 | /* If there was a single FORCED_LABEL, check for | |
798 | __builtin_setjmp_receiver with address of that label. */ | |
799 | if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi))) | |
800 | gsi_next_nondebug (&gsi); | |
801 | if (gsi_end_p (gsi)) | |
802 | return false; | |
803 | if (!gimple_call_builtin_p (gsi_stmt (gsi), BUILT_IN_SETJMP_RECEIVER)) | |
804 | return false; | |
805 | ||
806 | tree arg = gimple_call_arg (gsi_stmt (gsi), 0); | |
807 | if (TREE_CODE (arg) != ADDR_EXPR || TREE_OPERAND (arg, 0) != target) | |
808 | return false; | |
809 | } | |
810 | return true; | |
811 | } | |
812 | ||
813 | /* If BB is a basic block ending with __builtin_setjmp_setup, return edge | |
814 | from .ABNORMAL_DISPATCHER basic block to corresponding | |
815 | __builtin_setjmp_receiver basic block, otherwise return NULL. */ | |
816 | static edge | |
817 | builtin_setjmp_setup_bb (basic_block bb) | |
818 | { | |
819 | if (EDGE_COUNT (bb->succs) != 2 | |
820 | || ((EDGE_SUCC (bb, 0)->flags | |
821 | & (EDGE_ABNORMAL | EDGE_EH)) != EDGE_ABNORMAL | |
822 | && (EDGE_SUCC (bb, 1)->flags | |
823 | & (EDGE_ABNORMAL | EDGE_EH)) != EDGE_ABNORMAL)) | |
824 | return NULL; | |
825 | ||
826 | gimple_stmt_iterator gsi = gsi_last_nondebug_bb (bb); | |
827 | if (gsi_end_p (gsi) | |
828 | || !gimple_call_builtin_p (gsi_stmt (gsi), BUILT_IN_SETJMP_SETUP)) | |
829 | return NULL; | |
830 | ||
831 | tree arg = gimple_call_arg (gsi_stmt (gsi), 1); | |
832 | if (TREE_CODE (arg) != ADDR_EXPR | |
833 | || TREE_CODE (TREE_OPERAND (arg, 0)) != LABEL_DECL) | |
834 | return NULL; | |
835 | ||
836 | basic_block recv_bb = label_to_block (cfun, TREE_OPERAND (arg, 0)); | |
837 | if (EDGE_COUNT (recv_bb->preds) != 1 | |
838 | || (EDGE_PRED (recv_bb, 0)->flags | |
839 | & (EDGE_ABNORMAL | EDGE_EH)) != EDGE_ABNORMAL | |
840 | || (EDGE_SUCC (bb, 0)->dest != EDGE_PRED (recv_bb, 0)->src | |
841 | && EDGE_SUCC (bb, 1)->dest != EDGE_PRED (recv_bb, 0)->src)) | |
842 | return NULL; | |
843 | ||
844 | /* EDGE_PRED (recv_bb, 0)->src should be the .ABNORMAL_DISPATCHER bb. */ | |
845 | return EDGE_PRED (recv_bb, 0); | |
846 | } | |
847 | ||
53fe6e2f | 848 | /* Do cleanup_control_flow_bb in PRE order. */ |
849 | ||
850 | static bool | |
851 | cleanup_control_flow_pre () | |
852 | { | |
853 | bool retval = false; | |
854 | ||
11f5525b | 855 | /* We want remove_edge_and_dominated_blocks to only remove edges, |
856 | not dominated blocks which it does when dom info isn't available. | |
857 | Pretend so. */ | |
858 | dom_state saved_state = dom_info_state (CDI_DOMINATORS); | |
859 | set_dom_info_availability (CDI_DOMINATORS, DOM_NONE); | |
860 | ||
400c29ff | 861 | auto_vec<edge_iterator, 20> stack (n_basic_blocks_for_fn (cfun) + 2); |
53fe6e2f | 862 | auto_sbitmap visited (last_basic_block_for_fn (cfun)); |
863 | bitmap_clear (visited); | |
864 | ||
400c29ff | 865 | vec<edge, va_gc> *setjmp_vec = NULL; |
866 | auto_vec<basic_block, 4> abnormal_dispatchers; | |
867 | ||
53fe6e2f | 868 | stack.quick_push (ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs)); |
869 | ||
870 | while (! stack.is_empty ()) | |
871 | { | |
872 | /* Look at the edge on the top of the stack. */ | |
873 | edge_iterator ei = stack.last (); | |
874 | basic_block dest = ei_edge (ei)->dest; | |
875 | ||
876 | if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun) | |
400c29ff | 877 | && !bitmap_bit_p (visited, dest->index) |
878 | && (ei_container (ei) == setjmp_vec | |
879 | || !maybe_dead_abnormal_edge_p (ei_edge (ei)))) | |
53fe6e2f | 880 | { |
881 | bitmap_set_bit (visited, dest->index); | |
11f5525b | 882 | /* We only possibly remove edges from DEST here, leaving |
883 | possibly unreachable code in the IL. */ | |
53fe6e2f | 884 | retval |= cleanup_control_flow_bb (dest); |
400c29ff | 885 | |
886 | /* Check for __builtin_setjmp_setup. Edges from .ABNORMAL_DISPATCH | |
887 | to __builtin_setjmp_receiver will be normally ignored by | |
888 | maybe_dead_abnormal_edge_p. If DEST is a visited | |
889 | __builtin_setjmp_setup, queue edge from .ABNORMAL_DISPATCH | |
890 | to __builtin_setjmp_receiver, so that it will be visited too. */ | |
891 | if (edge e = builtin_setjmp_setup_bb (dest)) | |
892 | { | |
893 | vec_safe_push (setjmp_vec, e); | |
894 | if (vec_safe_length (setjmp_vec) == 1) | |
895 | stack.quick_push (ei_start (setjmp_vec)); | |
896 | } | |
897 | ||
898 | if ((ei_edge (ei)->flags | |
899 | & (EDGE_ABNORMAL | EDGE_EH)) == EDGE_ABNORMAL) | |
900 | { | |
901 | gimple_stmt_iterator gsi | |
902 | = gsi_start_nondebug_after_labels_bb (dest); | |
903 | gimple *g = gsi_stmt (gsi); | |
904 | if (g && gimple_call_internal_p (g, IFN_ABNORMAL_DISPATCHER)) | |
905 | abnormal_dispatchers.safe_push (dest); | |
906 | } | |
907 | ||
53fe6e2f | 908 | if (EDGE_COUNT (dest->succs) > 0) |
909 | stack.quick_push (ei_start (dest->succs)); | |
910 | } | |
911 | else | |
912 | { | |
913 | if (!ei_one_before_end_p (ei)) | |
914 | ei_next (&stack.last ()); | |
915 | else | |
400c29ff | 916 | { |
917 | if (ei_container (ei) == setjmp_vec) | |
918 | vec_safe_truncate (setjmp_vec, 0); | |
919 | stack.pop (); | |
920 | } | |
53fe6e2f | 921 | } |
922 | } | |
923 | ||
400c29ff | 924 | vec_free (setjmp_vec); |
925 | ||
926 | /* If we've marked .ABNORMAL_DISPATCHER basic block(s) as visited | |
927 | above, but haven't marked any of their successors as visited, | |
928 | unmark them now, so that they can be removed as useless. */ | |
929 | basic_block dispatcher_bb; | |
930 | unsigned int k; | |
931 | FOR_EACH_VEC_ELT (abnormal_dispatchers, k, dispatcher_bb) | |
932 | { | |
933 | edge e; | |
934 | edge_iterator ei; | |
935 | FOR_EACH_EDGE (e, ei, dispatcher_bb->succs) | |
936 | if (bitmap_bit_p (visited, e->dest->index)) | |
937 | break; | |
938 | if (e == NULL) | |
939 | bitmap_clear_bit (visited, dispatcher_bb->index); | |
940 | } | |
941 | ||
11f5525b | 942 | set_dom_info_availability (CDI_DOMINATORS, saved_state); |
943 | ||
944 | /* We are deleting BBs in non-reverse dominator order, make sure | |
945 | insert_debug_temps_for_defs is prepared for that. */ | |
946 | if (retval) | |
947 | free_dominance_info (CDI_DOMINATORS); | |
948 | ||
949 | /* Remove all now (and previously) unreachable blocks. */ | |
950 | for (int i = NUM_FIXED_BLOCKS; i < last_basic_block_for_fn (cfun); ++i) | |
951 | { | |
952 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i); | |
953 | if (bb && !bitmap_bit_p (visited, bb->index)) | |
954 | { | |
955 | if (!retval) | |
956 | free_dominance_info (CDI_DOMINATORS); | |
957 | delete_basic_block (bb); | |
958 | retval = true; | |
959 | } | |
960 | } | |
961 | ||
53fe6e2f | 962 | return retval; |
963 | } | |
964 | ||
f8b0a3dc | 965 | static bool |
966 | mfb_keep_latches (edge e) | |
967 | { | |
11f5525b | 968 | return !((dom_info_available_p (CDI_DOMINATORS) |
969 | && dominated_by_p (CDI_DOMINATORS, e->src, e->dest)) | |
970 | || (e->flags & EDGE_DFS_BACK)); | |
f8b0a3dc | 971 | } |
0c6b4703 | 972 | |
9ff23274 | 973 | /* Remove unreachable blocks and other miscellaneous clean up work. |
974 | Return true if the flowgraph was modified, false otherwise. */ | |
0c6b4703 | 975 | |
eb2a640e | 976 | static bool |
d7419e5b | 977 | cleanup_tree_cfg_noloop (unsigned ssa_update_flags) |
0c6b4703 | 978 | { |
0c6b4703 | 979 | timevar_push (TV_TREE_CLEANUP_CFG); |
980 | ||
f8b0a3dc | 981 | /* Ensure that we have single entries into loop headers. Otherwise |
982 | if one of the entries is becoming a latch due to CFG cleanup | |
983 | (from formerly being part of an irreducible region) then we mess | |
984 | up loop fixup and associate the old loop with a different region | |
985 | which makes niter upper bounds invalid. See for example PR80549. | |
986 | This needs to be done before we remove trivially dead edges as | |
987 | we need to capture the dominance state before the pending transform. */ | |
988 | if (current_loops) | |
989 | { | |
11f5525b | 990 | /* This needs backedges or dominators. */ |
991 | if (!dom_info_available_p (CDI_DOMINATORS)) | |
992 | mark_dfs_back_edges (); | |
993 | ||
f8b0a3dc | 994 | loop_p loop; |
995 | unsigned i; | |
996 | FOR_EACH_VEC_ELT (*get_loops (cfun), i, loop) | |
997 | if (loop && loop->header) | |
998 | { | |
999 | basic_block bb = loop->header; | |
1000 | edge_iterator ei; | |
1001 | edge e; | |
1002 | bool found_latch = false; | |
1003 | bool any_abnormal = false; | |
1004 | unsigned n = 0; | |
1005 | /* We are only interested in preserving existing loops, but | |
1006 | we need to check whether they are still real and of course | |
1007 | if we need to add a preheader at all. */ | |
1008 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1009 | { | |
1010 | if (e->flags & EDGE_ABNORMAL) | |
1011 | { | |
1012 | any_abnormal = true; | |
1013 | break; | |
1014 | } | |
11f5525b | 1015 | if ((dom_info_available_p (CDI_DOMINATORS) |
1016 | && dominated_by_p (CDI_DOMINATORS, e->src, bb)) | |
1017 | || (e->flags & EDGE_DFS_BACK)) | |
f8b0a3dc | 1018 | { |
1019 | found_latch = true; | |
1020 | continue; | |
1021 | } | |
1022 | n++; | |
1023 | } | |
1024 | /* If we have more than one entry to the loop header | |
1025 | create a forwarder. */ | |
1026 | if (found_latch && ! any_abnormal && n > 1) | |
1027 | { | |
1028 | edge fallthru = make_forwarder_block (bb, mfb_keep_latches, | |
1029 | NULL); | |
1030 | loop->header = fallthru->dest; | |
1031 | if (! loops_state_satisfies_p (LOOPS_NEED_FIXUP)) | |
1032 | { | |
1033 | /* The loop updating from the CFG hook is incomplete | |
1034 | when we have multiple latches, fixup manually. */ | |
1035 | remove_bb_from_loops (fallthru->src); | |
1036 | loop_p cloop = loop; | |
1037 | FOR_EACH_EDGE (e, ei, fallthru->src->preds) | |
1038 | cloop = find_common_loop (cloop, e->src->loop_father); | |
1039 | add_bb_to_loop (fallthru->src, cloop); | |
1040 | } | |
1041 | } | |
1042 | } | |
1043 | } | |
1044 | ||
89e9c625 | 1045 | /* Prepare the worklists of altered blocks. */ |
1046 | cfgcleanup_altered_bbs = BITMAP_ALLOC (NULL); | |
1047 | ||
1048 | /* Start by iterating over all basic blocks in PRE order looking for | |
1049 | edge removal opportunities. Do this first because incoming SSA form | |
1050 | may be invalid and we want to avoid performing SSA related tasks such | |
11f5525b | 1051 | as propgating out a PHI node during BB merging in that state. This |
1052 | also gets rid of unreachable blocks. */ | |
1053 | bool changed = cleanup_control_flow_pre (); | |
89e9c625 | 1054 | |
1055 | /* After doing the above SSA form should be valid (or an update SSA | |
1056 | should be required). */ | |
d7419e5b | 1057 | if (ssa_update_flags) |
1058 | update_ssa (ssa_update_flags); | |
89e9c625 | 1059 | |
11f5525b | 1060 | /* Compute dominator info which we need for the iterative process below. */ |
1061 | if (!dom_info_available_p (CDI_DOMINATORS)) | |
1062 | calculate_dominance_info (CDI_DOMINATORS); | |
1063 | else | |
1064 | checking_verify_dominators (CDI_DOMINATORS); | |
1065 | ||
89e9c625 | 1066 | /* During forwarder block cleanup, we may redirect edges out of |
1067 | SWITCH_EXPRs, which can get expensive. So we want to enable | |
1068 | recording of edge to CASE_LABEL_EXPR. */ | |
1069 | start_recording_case_labels (); | |
1070 | ||
1071 | /* Continue by iterating over all basic blocks looking for BB merging | |
1072 | opportunities. We cannot use FOR_EACH_BB_FN for the BB iteration | |
1073 | since the basic blocks may get removed. */ | |
1074 | unsigned n = last_basic_block_for_fn (cfun); | |
1075 | for (unsigned i = NUM_FIXED_BLOCKS; i < n; i++) | |
1076 | { | |
1077 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i); | |
1078 | if (bb) | |
1079 | changed |= cleanup_tree_cfg_bb (bb); | |
1080 | } | |
1081 | ||
1082 | /* Now process the altered blocks, as long as any are available. */ | |
1083 | while (!bitmap_empty_p (cfgcleanup_altered_bbs)) | |
1084 | { | |
1085 | unsigned i = bitmap_first_set_bit (cfgcleanup_altered_bbs); | |
1086 | bitmap_clear_bit (cfgcleanup_altered_bbs, i); | |
1087 | if (i < NUM_FIXED_BLOCKS) | |
1088 | continue; | |
1089 | ||
1090 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i); | |
1091 | if (!bb) | |
1092 | continue; | |
1093 | ||
11f5525b | 1094 | /* BB merging done by cleanup_tree_cfg_bb can end up propagating |
1095 | out single-argument PHIs which in turn can expose | |
1096 | cleanup_control_flow_bb opportunities so we have to repeat | |
1097 | that here. */ | |
89e9c625 | 1098 | changed |= cleanup_control_flow_bb (bb); |
1099 | changed |= cleanup_tree_cfg_bb (bb); | |
1100 | } | |
1101 | ||
1102 | end_recording_case_labels (); | |
1103 | BITMAP_FREE (cfgcleanup_altered_bbs); | |
31a8456e | 1104 | |
50b08d37 | 1105 | gcc_assert (dom_info_available_p (CDI_DOMINATORS)); |
c3f8ce55 | 1106 | |
1107 | /* Do not renumber blocks if the SCEV cache is active, it is indexed by | |
1108 | basic-block numbers. */ | |
1109 | if (! scev_initialized_p ()) | |
1110 | compact_blocks (); | |
bfd49939 | 1111 | |
382ecba7 | 1112 | checking_verify_flow_info (); |
0c6b4703 | 1113 | |
bfd49939 | 1114 | timevar_pop (TV_TREE_CLEANUP_CFG); |
0c6b4703 | 1115 | |
eb2a640e | 1116 | if (changed && current_loops) |
34df3cfb | 1117 | { |
1118 | /* Removing edges and/or blocks may make recorded bounds refer | |
1119 | to stale GIMPLE stmts now, so clear them. */ | |
1120 | free_numbers_of_iterations_estimates (cfun); | |
1121 | loops_state_set (LOOPS_NEED_FIXUP); | |
1122 | } | |
eb2a640e | 1123 | |
9ff23274 | 1124 | return changed; |
bfd49939 | 1125 | } |
1126 | ||
eb2a640e | 1127 | /* Repairs loop structures. */ |
bfd49939 | 1128 | |
eb2a640e | 1129 | static void |
1130 | repair_loop_structures (void) | |
bfd49939 | 1131 | { |
4b366dd3 | 1132 | bitmap changed_bbs; |
b6f3c6f1 | 1133 | unsigned n_new_loops; |
4b366dd3 | 1134 | |
4e976818 | 1135 | calculate_dominance_info (CDI_DOMINATORS); |
1136 | ||
4b366dd3 | 1137 | timevar_push (TV_REPAIR_LOOPS); |
1138 | changed_bbs = BITMAP_ALLOC (NULL); | |
b6f3c6f1 | 1139 | n_new_loops = fix_loop_structure (changed_bbs); |
bfd49939 | 1140 | |
eb2a640e | 1141 | /* This usually does nothing. But sometimes parts of cfg that originally |
1142 | were inside a loop get out of it due to edge removal (since they | |
b6f3c6f1 | 1143 | become unreachable by back edges from latch). Also a former |
1144 | irreducible loop can become reducible - in this case force a full | |
1145 | rewrite into loop-closed SSA form. */ | |
f24ec26f | 1146 | if (loops_state_satisfies_p (LOOP_CLOSED_SSA)) |
b6f3c6f1 | 1147 | rewrite_into_loop_closed_ssa (n_new_loops ? NULL : changed_bbs, |
1148 | TODO_update_ssa); | |
bfd49939 | 1149 | |
eb2a640e | 1150 | BITMAP_FREE (changed_bbs); |
bfd49939 | 1151 | |
382ecba7 | 1152 | checking_verify_loop_structure (); |
eb2a640e | 1153 | scev_reset (); |
1154 | ||
4b366dd3 | 1155 | timevar_pop (TV_REPAIR_LOOPS); |
eb2a640e | 1156 | } |
1157 | ||
1158 | /* Cleanup cfg and repair loop structures. */ | |
1159 | ||
1160 | bool | |
d7419e5b | 1161 | cleanup_tree_cfg (unsigned ssa_update_flags) |
eb2a640e | 1162 | { |
d7419e5b | 1163 | bool changed = cleanup_tree_cfg_noloop (ssa_update_flags); |
eb2a640e | 1164 | |
1165 | if (current_loops != NULL | |
f24ec26f | 1166 | && loops_state_satisfies_p (LOOPS_NEED_FIXUP)) |
eb2a640e | 1167 | repair_loop_structures (); |
1168 | ||
6fa78c7b | 1169 | return changed; |
bfd49939 | 1170 | } |
1171 | ||
f6568ea4 | 1172 | /* Tries to merge the PHI nodes at BB into those at BB's sole successor. |
1173 | Returns true if successful. */ | |
bfd49939 | 1174 | |
f6568ea4 | 1175 | static bool |
bfd49939 | 1176 | remove_forwarder_block_with_phi (basic_block bb) |
1177 | { | |
1178 | edge succ = single_succ_edge (bb); | |
1179 | basic_block dest = succ->dest; | |
42acab1c | 1180 | gimple *label; |
bfd49939 | 1181 | basic_block dombb, domdest, dom; |
1182 | ||
1183 | /* We check for infinite loops already in tree_forwarder_block_p. | |
1184 | However it may happen that the infinite loop is created | |
1185 | afterwards due to removal of forwarders. */ | |
1186 | if (dest == bb) | |
f6568ea4 | 1187 | return false; |
3ff1ad36 | 1188 | |
1189 | /* Removal of forwarders may expose new natural loops and thus | |
1190 | a block may turn into a loop header. */ | |
1191 | if (current_loops && bb_loop_header_p (bb)) | |
1192 | return false; | |
bfd49939 | 1193 | |
1194 | /* If the destination block consists of a nonlocal label, do not | |
1195 | merge it. */ | |
1196 | label = first_stmt (dest); | |
1a91d914 | 1197 | if (label) |
1198 | if (glabel *label_stmt = dyn_cast <glabel *> (label)) | |
1199 | if (DECL_NONLOCAL (gimple_label_label (label_stmt))) | |
1200 | return false; | |
bfd49939 | 1201 | |
31a370d3 | 1202 | /* Record BB's single pred in case we need to update the father |
1203 | loop's latch information later. */ | |
1204 | basic_block pred = NULL; | |
1205 | if (single_pred_p (bb)) | |
1206 | pred = single_pred (bb); | |
52455dd5 | 1207 | bool dest_single_pred_p = single_pred_p (dest); |
31a370d3 | 1208 | |
bfd49939 | 1209 | /* Redirect each incoming edge to BB to DEST. */ |
1210 | while (EDGE_COUNT (bb->preds) > 0) | |
1211 | { | |
1212 | edge e = EDGE_PRED (bb, 0), s; | |
1a91d914 | 1213 | gphi_iterator gsi; |
bfd49939 | 1214 | |
1215 | s = find_edge (e->src, dest); | |
1216 | if (s) | |
1217 | { | |
1218 | /* We already have an edge S from E->src to DEST. If S and | |
1219 | E->dest's sole successor edge have the same PHI arguments | |
1220 | at DEST, redirect S to DEST. */ | |
1221 | if (phi_alternatives_equal (dest, s, succ)) | |
1222 | { | |
1223 | e = redirect_edge_and_branch (e, dest); | |
d03ba86f | 1224 | redirect_edge_var_map_clear (e); |
bfd49939 | 1225 | continue; |
1226 | } | |
1227 | ||
1228 | /* PHI arguments are different. Create a forwarder block by | |
1229 | splitting E so that we can merge PHI arguments on E to | |
1230 | DEST. */ | |
1231 | e = single_succ_edge (split_edge (e)); | |
1232 | } | |
ffeccaca | 1233 | else |
1234 | { | |
1235 | /* If we merge the forwarder into a loop header verify if we | |
1236 | are creating another loop latch edge. If so, reset | |
1237 | number of iteration information of the loop. */ | |
1238 | if (dest->loop_father->header == dest | |
1239 | && dominated_by_p (CDI_DOMINATORS, e->src, dest)) | |
1240 | { | |
1241 | dest->loop_father->any_upper_bound = false; | |
1242 | dest->loop_father->any_likely_upper_bound = false; | |
46480a95 | 1243 | free_numbers_of_iterations_estimates (dest->loop_father); |
ffeccaca | 1244 | } |
1245 | } | |
bfd49939 | 1246 | |
1247 | s = redirect_edge_and_branch (e, dest); | |
1248 | ||
1249 | /* redirect_edge_and_branch must not create a new edge. */ | |
1250 | gcc_assert (s == e); | |
1251 | ||
1252 | /* Add to the PHI nodes at DEST each PHI argument removed at the | |
1253 | destination of E. */ | |
75a70cf9 | 1254 | for (gsi = gsi_start_phis (dest); |
1255 | !gsi_end_p (gsi); | |
1256 | gsi_next (&gsi)) | |
bfd49939 | 1257 | { |
1a91d914 | 1258 | gphi *phi = gsi.phi (); |
75a70cf9 | 1259 | tree def = gimple_phi_arg_def (phi, succ->dest_idx); |
be1e7283 | 1260 | location_t locus = gimple_phi_arg_location_from_edge (phi, succ); |
bfd49939 | 1261 | |
1262 | if (TREE_CODE (def) == SSA_NAME) | |
1263 | { | |
bfd49939 | 1264 | /* If DEF is one of the results of PHI nodes removed during |
1265 | redirection, replace it with the PHI argument that used | |
1266 | to be on E. */ | |
06ecf488 | 1267 | vec<edge_var_map> *head = redirect_edge_var_map_vector (e); |
1268 | size_t length = head ? head->length () : 0; | |
1269 | for (size_t i = 0; i < length; i++) | |
bfd49939 | 1270 | { |
06ecf488 | 1271 | edge_var_map *vm = &(*head)[i]; |
d03ba86f | 1272 | tree old_arg = redirect_edge_var_map_result (vm); |
1273 | tree new_arg = redirect_edge_var_map_def (vm); | |
bfd49939 | 1274 | |
1275 | if (def == old_arg) | |
1276 | { | |
1277 | def = new_arg; | |
efbcb6de | 1278 | locus = redirect_edge_var_map_location (vm); |
bfd49939 | 1279 | break; |
1280 | } | |
1281 | } | |
1282 | } | |
1283 | ||
60d535d2 | 1284 | add_phi_arg (phi, def, s, locus); |
bfd49939 | 1285 | } |
1286 | ||
d03ba86f | 1287 | redirect_edge_var_map_clear (e); |
bfd49939 | 1288 | } |
1289 | ||
a894735c | 1290 | /* Move debug statements. Reset them if the destination does not |
1291 | have a single predecessor. */ | |
52455dd5 | 1292 | move_debug_stmts_from_forwarder (bb, dest, dest_single_pred_p); |
a894735c | 1293 | |
bfd49939 | 1294 | /* Update the dominators. */ |
1295 | dombb = get_immediate_dominator (CDI_DOMINATORS, bb); | |
1296 | domdest = get_immediate_dominator (CDI_DOMINATORS, dest); | |
1297 | if (domdest == bb) | |
1298 | { | |
1299 | /* Shortcut to avoid calling (relatively expensive) | |
1300 | nearest_common_dominator unless necessary. */ | |
1301 | dom = dombb; | |
1302 | } | |
1303 | else | |
1304 | dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb); | |
1305 | ||
1306 | set_immediate_dominator (CDI_DOMINATORS, dest, dom); | |
1307 | ||
31a370d3 | 1308 | /* Adjust latch infomation of BB's parent loop as otherwise |
1309 | the cfg hook has a hard time not to kill the loop. */ | |
1310 | if (current_loops && bb->loop_father->latch == bb) | |
1311 | bb->loop_father->latch = pred; | |
1312 | ||
bfd49939 | 1313 | /* Remove BB since all of BB's incoming edges have been redirected |
1314 | to DEST. */ | |
1315 | delete_basic_block (bb); | |
f6568ea4 | 1316 | |
1317 | return true; | |
bfd49939 | 1318 | } |
1319 | ||
1320 | /* This pass merges PHI nodes if one feeds into another. For example, | |
1321 | suppose we have the following: | |
1322 | ||
1323 | goto <bb 9> (<L9>); | |
1324 | ||
1325 | <L8>:; | |
1326 | tem_17 = foo (); | |
1327 | ||
1328 | # tem_6 = PHI <tem_17(8), tem_23(7)>; | |
1329 | <L9>:; | |
1330 | ||
1331 | # tem_3 = PHI <tem_6(9), tem_2(5)>; | |
1332 | <L10>:; | |
1333 | ||
1334 | Then we merge the first PHI node into the second one like so: | |
1335 | ||
1336 | goto <bb 9> (<L10>); | |
1337 | ||
1338 | <L8>:; | |
1339 | tem_17 = foo (); | |
1340 | ||
1341 | # tem_3 = PHI <tem_23(7), tem_2(5), tem_17(8)>; | |
1342 | <L10>:; | |
1343 | */ | |
1344 | ||
65b0537f | 1345 | namespace { |
1346 | ||
1347 | const pass_data pass_data_merge_phi = | |
1348 | { | |
1349 | GIMPLE_PASS, /* type */ | |
1350 | "mergephi", /* name */ | |
1351 | OPTGROUP_NONE, /* optinfo_flags */ | |
65b0537f | 1352 | TV_TREE_MERGE_PHI, /* tv_id */ |
1353 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1354 | 0, /* properties_provided */ | |
1355 | 0, /* properties_destroyed */ | |
1356 | 0, /* todo_flags_start */ | |
8b88439e | 1357 | 0, /* todo_flags_finish */ |
65b0537f | 1358 | }; |
1359 | ||
1360 | class pass_merge_phi : public gimple_opt_pass | |
bfd49939 | 1361 | { |
65b0537f | 1362 | public: |
1363 | pass_merge_phi (gcc::context *ctxt) | |
1364 | : gimple_opt_pass (pass_data_merge_phi, ctxt) | |
1365 | {} | |
1366 | ||
1367 | /* opt_pass methods: */ | |
1368 | opt_pass * clone () { return new pass_merge_phi (m_ctxt); } | |
1369 | virtual unsigned int execute (function *); | |
1370 | ||
1371 | }; // class pass_merge_phi | |
1372 | ||
1373 | unsigned int | |
1374 | pass_merge_phi::execute (function *fun) | |
1375 | { | |
1376 | basic_block *worklist = XNEWVEC (basic_block, n_basic_blocks_for_fn (fun)); | |
bfd49939 | 1377 | basic_block *current = worklist; |
1378 | basic_block bb; | |
1379 | ||
1380 | calculate_dominance_info (CDI_DOMINATORS); | |
1381 | ||
1382 | /* Find all PHI nodes that we may be able to merge. */ | |
65b0537f | 1383 | FOR_EACH_BB_FN (bb, fun) |
bfd49939 | 1384 | { |
1385 | basic_block dest; | |
1386 | ||
1387 | /* Look for a forwarder block with PHI nodes. */ | |
1388 | if (!tree_forwarder_block_p (bb, true)) | |
1389 | continue; | |
1390 | ||
1391 | dest = single_succ (bb); | |
1392 | ||
1393 | /* We have to feed into another basic block with PHI | |
1394 | nodes. */ | |
be2517f5 | 1395 | if (gimple_seq_empty_p (phi_nodes (dest)) |
bfd49939 | 1396 | /* We don't want to deal with a basic block with |
1397 | abnormal edges. */ | |
f1047120 | 1398 | || bb_has_abnormal_pred (bb)) |
bfd49939 | 1399 | continue; |
1400 | ||
1401 | if (!dominated_by_p (CDI_DOMINATORS, dest, bb)) | |
1402 | { | |
1403 | /* If BB does not dominate DEST, then the PHI nodes at | |
1404 | DEST must be the only users of the results of the PHI | |
1405 | nodes at BB. */ | |
1406 | *current++ = bb; | |
1407 | } | |
cbbe9173 | 1408 | else |
1409 | { | |
1a91d914 | 1410 | gphi_iterator gsi; |
f9ead664 | 1411 | unsigned int dest_idx = single_succ_edge (bb)->dest_idx; |
cbbe9173 | 1412 | |
1413 | /* BB dominates DEST. There may be many users of the PHI | |
1414 | nodes in BB. However, there is still a trivial case we | |
1415 | can handle. If the result of every PHI in BB is used | |
1416 | only by a PHI in DEST, then we can trivially merge the | |
1417 | PHI nodes from BB into DEST. */ | |
75a70cf9 | 1418 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
1419 | gsi_next (&gsi)) | |
cbbe9173 | 1420 | { |
1a91d914 | 1421 | gphi *phi = gsi.phi (); |
75a70cf9 | 1422 | tree result = gimple_phi_result (phi); |
cbbe9173 | 1423 | use_operand_p imm_use; |
42acab1c | 1424 | gimple *use_stmt; |
cbbe9173 | 1425 | |
1426 | /* If the PHI's result is never used, then we can just | |
1427 | ignore it. */ | |
72e3ec84 | 1428 | if (has_zero_uses (result)) |
cbbe9173 | 1429 | continue; |
1430 | ||
1431 | /* Get the single use of the result of this PHI node. */ | |
1432 | if (!single_imm_use (result, &imm_use, &use_stmt) | |
75a70cf9 | 1433 | || gimple_code (use_stmt) != GIMPLE_PHI |
1434 | || gimple_bb (use_stmt) != dest | |
1435 | || gimple_phi_arg_def (use_stmt, dest_idx) != result) | |
cbbe9173 | 1436 | break; |
1437 | } | |
1438 | ||
334ec2d8 | 1439 | /* If the loop above iterated through all the PHI nodes |
cbbe9173 | 1440 | in BB, then we can merge the PHIs from BB into DEST. */ |
75a70cf9 | 1441 | if (gsi_end_p (gsi)) |
cbbe9173 | 1442 | *current++ = bb; |
1443 | } | |
bfd49939 | 1444 | } |
1445 | ||
1446 | /* Now let's drain WORKLIST. */ | |
f6568ea4 | 1447 | bool changed = false; |
bfd49939 | 1448 | while (current != worklist) |
1449 | { | |
1450 | bb = *--current; | |
f6568ea4 | 1451 | changed |= remove_forwarder_block_with_phi (bb); |
bfd49939 | 1452 | } |
bfd49939 | 1453 | free (worklist); |
f6568ea4 | 1454 | |
1455 | /* Removing forwarder blocks can cause formerly irreducible loops | |
1456 | to become reducible if we merged two entry blocks. */ | |
1457 | if (changed | |
1458 | && current_loops) | |
1459 | loops_state_set (LOOPS_NEED_FIXUP); | |
1460 | ||
2a1990e9 | 1461 | return 0; |
bfd49939 | 1462 | } |
1463 | ||
cbe8bda8 | 1464 | } // anon namespace |
1465 | ||
1466 | gimple_opt_pass * | |
1467 | make_pass_merge_phi (gcc::context *ctxt) | |
1468 | { | |
1469 | return new pass_merge_phi (ctxt); | |
1470 | } | |
424a4a92 | 1471 | |
1472 | /* Pass: cleanup the CFG just before expanding trees to RTL. | |
1473 | This is just a round of label cleanups and case node grouping | |
1474 | because after the tree optimizers have run such cleanups may | |
1475 | be necessary. */ | |
1476 | ||
1477 | static unsigned int | |
1478 | execute_cleanup_cfg_post_optimizing (void) | |
1479 | { | |
25959a39 | 1480 | unsigned int todo = execute_fixup_cfg (); |
424a4a92 | 1481 | if (cleanup_tree_cfg ()) |
25959a39 | 1482 | { |
1483 | todo &= ~TODO_cleanup_cfg; | |
1484 | todo |= TODO_update_ssa; | |
1485 | } | |
424a4a92 | 1486 | maybe_remove_unreachable_handlers (); |
1487 | cleanup_dead_labels (); | |
eede5d6f | 1488 | if (group_case_labels ()) |
1489 | todo |= TODO_cleanup_cfg; | |
424a4a92 | 1490 | if ((flag_compare_debug_opt || flag_compare_debug) |
1491 | && flag_dump_final_insns) | |
1492 | { | |
1493 | FILE *final_output = fopen (flag_dump_final_insns, "a"); | |
1494 | ||
1495 | if (!final_output) | |
1496 | { | |
1497 | error ("could not open final insn dump file %qs: %m", | |
1498 | flag_dump_final_insns); | |
1499 | flag_dump_final_insns = NULL; | |
1500 | } | |
1501 | else | |
1502 | { | |
1503 | int save_unnumbered = flag_dump_unnumbered; | |
1504 | int save_noaddr = flag_dump_noaddr; | |
1505 | ||
1506 | flag_dump_noaddr = flag_dump_unnumbered = 1; | |
1507 | fprintf (final_output, "\n"); | |
bce107d7 | 1508 | dump_enumerated_decls (final_output, |
1509 | dump_flags | TDF_SLIM | TDF_NOUID); | |
424a4a92 | 1510 | flag_dump_noaddr = save_noaddr; |
1511 | flag_dump_unnumbered = save_unnumbered; | |
1512 | if (fclose (final_output)) | |
1513 | { | |
1514 | error ("could not close final insn dump file %qs: %m", | |
1515 | flag_dump_final_insns); | |
1516 | flag_dump_final_insns = NULL; | |
1517 | } | |
1518 | } | |
1519 | } | |
1520 | return todo; | |
1521 | } | |
1522 | ||
1523 | namespace { | |
1524 | ||
1525 | const pass_data pass_data_cleanup_cfg_post_optimizing = | |
1526 | { | |
1527 | GIMPLE_PASS, /* type */ | |
1528 | "optimized", /* name */ | |
1529 | OPTGROUP_NONE, /* optinfo_flags */ | |
424a4a92 | 1530 | TV_TREE_CLEANUP_CFG, /* tv_id */ |
1531 | PROP_cfg, /* properties_required */ | |
1532 | 0, /* properties_provided */ | |
1533 | 0, /* properties_destroyed */ | |
1534 | 0, /* todo_flags_start */ | |
1535 | TODO_remove_unused_locals, /* todo_flags_finish */ | |
1536 | }; | |
1537 | ||
1538 | class pass_cleanup_cfg_post_optimizing : public gimple_opt_pass | |
1539 | { | |
1540 | public: | |
1541 | pass_cleanup_cfg_post_optimizing (gcc::context *ctxt) | |
1542 | : gimple_opt_pass (pass_data_cleanup_cfg_post_optimizing, ctxt) | |
1543 | {} | |
1544 | ||
1545 | /* opt_pass methods: */ | |
65b0537f | 1546 | virtual unsigned int execute (function *) |
1547 | { | |
1548 | return execute_cleanup_cfg_post_optimizing (); | |
1549 | } | |
424a4a92 | 1550 | |
1551 | }; // class pass_cleanup_cfg_post_optimizing | |
1552 | ||
1553 | } // anon namespace | |
1554 | ||
1555 | gimple_opt_pass * | |
1556 | make_pass_cleanup_cfg_post_optimizing (gcc::context *ctxt) | |
1557 | { | |
1558 | return new pass_cleanup_cfg_post_optimizing (ctxt); | |
1559 | } | |
1560 | ||
1561 | ||
9eafff7e | 1562 | /* Delete all unreachable basic blocks and update callgraph. |
1563 | Doing so is somewhat nontrivial because we need to update all clones and | |
1564 | remove inline function that become unreachable. */ | |
1565 | ||
1566 | bool | |
1567 | delete_unreachable_blocks_update_callgraph (cgraph_node *dst_node, | |
1568 | bool update_clones) | |
1569 | { | |
1570 | bool changed = false; | |
1571 | basic_block b, next_bb; | |
1572 | ||
1573 | find_unreachable_blocks (); | |
1574 | ||
1575 | /* Delete all unreachable basic blocks. */ | |
1576 | ||
1577 | for (b = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; b | |
1578 | != EXIT_BLOCK_PTR_FOR_FN (cfun); b = next_bb) | |
1579 | { | |
1580 | next_bb = b->next_bb; | |
1581 | ||
1582 | if (!(b->flags & BB_REACHABLE)) | |
1583 | { | |
1584 | gimple_stmt_iterator bsi; | |
1585 | ||
1586 | for (bsi = gsi_start_bb (b); !gsi_end_p (bsi); gsi_next (&bsi)) | |
1587 | { | |
1588 | struct cgraph_edge *e; | |
1589 | struct cgraph_node *node; | |
1590 | ||
1591 | dst_node->remove_stmt_references (gsi_stmt (bsi)); | |
1592 | ||
1593 | if (gimple_code (gsi_stmt (bsi)) == GIMPLE_CALL | |
1594 | &&(e = dst_node->get_edge (gsi_stmt (bsi))) != NULL) | |
1595 | { | |
1596 | if (!e->inline_failed) | |
1597 | e->callee->remove_symbol_and_inline_clones (dst_node); | |
1598 | else | |
1599 | e->remove (); | |
1600 | } | |
1601 | if (update_clones && dst_node->clones) | |
1602 | for (node = dst_node->clones; node != dst_node;) | |
1603 | { | |
1604 | node->remove_stmt_references (gsi_stmt (bsi)); | |
1605 | if (gimple_code (gsi_stmt (bsi)) == GIMPLE_CALL | |
1606 | && (e = node->get_edge (gsi_stmt (bsi))) != NULL) | |
1607 | { | |
1608 | if (!e->inline_failed) | |
1609 | e->callee->remove_symbol_and_inline_clones (dst_node); | |
1610 | else | |
1611 | e->remove (); | |
1612 | } | |
1613 | ||
1614 | if (node->clones) | |
1615 | node = node->clones; | |
1616 | else if (node->next_sibling_clone) | |
1617 | node = node->next_sibling_clone; | |
1618 | else | |
1619 | { | |
1620 | while (node != dst_node && !node->next_sibling_clone) | |
1621 | node = node->clone_of; | |
1622 | if (node != dst_node) | |
1623 | node = node->next_sibling_clone; | |
1624 | } | |
1625 | } | |
1626 | } | |
1627 | delete_basic_block (b); | |
1628 | changed = true; | |
1629 | } | |
1630 | } | |
1631 | ||
1632 | return changed; | |
1633 | } | |
1634 |