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c9784e6d | 1 | /* CFG cleanup for trees. |
818ab71a | 2 | Copyright (C) 2001-2016 Free Software Foundation, Inc. |
c9784e6d KH |
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 | |
9dcd6f09 | 8 | the Free Software Foundation; either version 3, or (at your option) |
c9784e6d KH |
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 | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
c9784e6d KH |
19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "coretypes.h" | |
c7131fb2 | 23 | #include "backend.h" |
957060b5 | 24 | #include "rtl.h" |
c9784e6d | 25 | #include "tree.h" |
c7131fb2 | 26 | #include "gimple.h" |
957060b5 AM |
27 | #include "cfghooks.h" |
28 | #include "tree-pass.h" | |
c7131fb2 | 29 | #include "ssa.h" |
957060b5 | 30 | #include "diagnostic-core.h" |
40e23961 | 31 | #include "fold-const.h" |
60393bbc AM |
32 | #include "cfganal.h" |
33 | #include "cfgcleanup.h" | |
2fb9a547 | 34 | #include "tree-eh.h" |
45b0be94 | 35 | #include "gimplify.h" |
5be5c238 | 36 | #include "gimple-iterator.h" |
442b4905 | 37 | #include "tree-cfg.h" |
e28030cf | 38 | #include "tree-ssa-loop-manip.h" |
442b4905 | 39 | #include "tree-dfa.h" |
7a300452 | 40 | #include "tree-ssa.h" |
c9784e6d | 41 | #include "cfgloop.h" |
17684618 | 42 | #include "tree-scalar-evolution.h" |
c3bea076 RB |
43 | #include "gimple-match.h" |
44 | #include "gimple-fold.h" | |
45 | ||
c9784e6d | 46 | |
672987e8 ZD |
47 | /* The set of blocks in that at least one of the following changes happened: |
48 | -- the statement at the end of the block was changed | |
49 | -- the block was newly created | |
50 | -- the set of the predecessors of the block changed | |
51 | -- the set of the successors of the block changed | |
52 | ??? Maybe we could track these changes separately, since they determine | |
53 | what cleanups it makes sense to try on the block. */ | |
54 | bitmap cfgcleanup_altered_bbs; | |
55 | ||
c9784e6d KH |
56 | /* Remove any fallthru edge from EV. Return true if an edge was removed. */ |
57 | ||
58 | static bool | |
9771b263 | 59 | remove_fallthru_edge (vec<edge, va_gc> *ev) |
c9784e6d KH |
60 | { |
61 | edge_iterator ei; | |
62 | edge e; | |
63 | ||
64 | FOR_EACH_EDGE (e, ei, ev) | |
65 | if ((e->flags & EDGE_FALLTHRU) != 0) | |
66 | { | |
0107dca2 RB |
67 | if (e->flags & EDGE_COMPLEX) |
68 | e->flags &= ~EDGE_FALLTHRU; | |
69 | else | |
70 | remove_edge_and_dominated_blocks (e); | |
c9784e6d KH |
71 | return true; |
72 | } | |
73 | return false; | |
74 | } | |
75 | ||
726a989a | 76 | |
c9784e6d KH |
77 | /* Disconnect an unreachable block in the control expression starting |
78 | at block BB. */ | |
79 | ||
80 | static bool | |
7b5ab0cd RB |
81 | cleanup_control_expr_graph (basic_block bb, gimple_stmt_iterator gsi, |
82 | bool first_p) | |
c9784e6d KH |
83 | { |
84 | edge taken_edge; | |
85 | bool retval = false; | |
355fe088 | 86 | gimple *stmt = gsi_stmt (gsi); |
c9784e6d KH |
87 | |
88 | if (!single_succ_p (bb)) | |
89 | { | |
90 | edge e; | |
91 | edge_iterator ei; | |
6ac01510 | 92 | bool warned; |
c3bea076 | 93 | tree val = NULL_TREE; |
6ac01510 ILT |
94 | |
95 | fold_defer_overflow_warnings (); | |
37530014 RG |
96 | switch (gimple_code (stmt)) |
97 | { | |
98 | case GIMPLE_COND: | |
7b5ab0cd RB |
99 | /* During a first iteration on the CFG only remove trivially |
100 | dead edges but mark other conditions for re-evaluation. */ | |
101 | if (first_p) | |
102 | { | |
103 | val = const_binop (gimple_cond_code (stmt), boolean_type_node, | |
104 | gimple_cond_lhs (stmt), | |
105 | gimple_cond_rhs (stmt)); | |
106 | if (! val) | |
107 | bitmap_set_bit (cfgcleanup_altered_bbs, bb->index); | |
108 | } | |
109 | else | |
110 | { | |
111 | code_helper rcode; | |
112 | tree ops[3] = {}; | |
113 | if (gimple_simplify (stmt, &rcode, ops, NULL, no_follow_ssa_edges, | |
114 | no_follow_ssa_edges) | |
115 | && rcode == INTEGER_CST) | |
116 | val = ops[0]; | |
117 | } | |
118 | break; | |
37530014 RG |
119 | |
120 | case GIMPLE_SWITCH: | |
538dd0b7 | 121 | val = gimple_switch_index (as_a <gswitch *> (stmt)); |
37530014 RG |
122 | break; |
123 | ||
124 | default: | |
c3bea076 | 125 | ; |
37530014 | 126 | } |
c9784e6d KH |
127 | taken_edge = find_taken_edge (bb, val); |
128 | if (!taken_edge) | |
6ac01510 ILT |
129 | { |
130 | fold_undefer_and_ignore_overflow_warnings (); | |
131 | return false; | |
132 | } | |
c9784e6d KH |
133 | |
134 | /* Remove all the edges except the one that is always executed. */ | |
6ac01510 | 135 | warned = false; |
c9784e6d KH |
136 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) |
137 | { | |
138 | if (e != taken_edge) | |
139 | { | |
6ac01510 ILT |
140 | if (!warned) |
141 | { | |
142 | fold_undefer_overflow_warnings | |
726a989a | 143 | (true, stmt, WARN_STRICT_OVERFLOW_CONDITIONAL); |
6ac01510 ILT |
144 | warned = true; |
145 | } | |
146 | ||
c9784e6d KH |
147 | taken_edge->probability += e->probability; |
148 | taken_edge->count += e->count; | |
672987e8 | 149 | remove_edge_and_dominated_blocks (e); |
c9784e6d KH |
150 | retval = true; |
151 | } | |
152 | else | |
153 | ei_next (&ei); | |
154 | } | |
6ac01510 ILT |
155 | if (!warned) |
156 | fold_undefer_and_ignore_overflow_warnings (); | |
c9784e6d KH |
157 | if (taken_edge->probability > REG_BR_PROB_BASE) |
158 | taken_edge->probability = REG_BR_PROB_BASE; | |
159 | } | |
160 | else | |
161 | taken_edge = single_succ_edge (bb); | |
162 | ||
672987e8 | 163 | bitmap_set_bit (cfgcleanup_altered_bbs, bb->index); |
726a989a | 164 | gsi_remove (&gsi, true); |
c9784e6d KH |
165 | taken_edge->flags = EDGE_FALLTHRU; |
166 | ||
c9784e6d KH |
167 | return retval; |
168 | } | |
169 | ||
58041fe6 MJ |
170 | /* Cleanup the GF_CALL_CTRL_ALTERING flag according to |
171 | to updated gimple_call_flags. */ | |
172 | ||
173 | static void | |
355fe088 | 174 | cleanup_call_ctrl_altering_flag (gimple *bb_end) |
58041fe6 MJ |
175 | { |
176 | if (!is_gimple_call (bb_end) | |
177 | || !gimple_call_ctrl_altering_p (bb_end)) | |
178 | return; | |
179 | ||
180 | int flags = gimple_call_flags (bb_end); | |
181 | if (((flags & (ECF_CONST | ECF_PURE)) | |
182 | && !(flags & ECF_LOOPING_CONST_OR_PURE)) | |
183 | || (flags & ECF_LEAF)) | |
184 | gimple_call_set_ctrl_altering (bb_end, false); | |
185 | } | |
186 | ||
672987e8 ZD |
187 | /* Try to remove superfluous control structures in basic block BB. Returns |
188 | true if anything changes. */ | |
c9784e6d KH |
189 | |
190 | static bool | |
7b5ab0cd | 191 | cleanup_control_flow_bb (basic_block bb, bool first_p) |
c9784e6d | 192 | { |
726a989a | 193 | gimple_stmt_iterator gsi; |
c9784e6d | 194 | bool retval = false; |
355fe088 | 195 | gimple *stmt; |
c9784e6d | 196 | |
672987e8 ZD |
197 | /* If the last statement of the block could throw and now cannot, |
198 | we need to prune cfg. */ | |
726a989a | 199 | retval |= gimple_purge_dead_eh_edges (bb); |
672987e8 | 200 | |
3be33b6e | 201 | gsi = gsi_last_nondebug_bb (bb); |
726a989a | 202 | if (gsi_end_p (gsi)) |
672987e8 ZD |
203 | return retval; |
204 | ||
726a989a | 205 | stmt = gsi_stmt (gsi); |
672987e8 | 206 | |
58041fe6 MJ |
207 | /* Try to cleanup ctrl altering flag for call which ends bb. */ |
208 | cleanup_call_ctrl_altering_flag (stmt); | |
209 | ||
726a989a RB |
210 | if (gimple_code (stmt) == GIMPLE_COND |
211 | || gimple_code (stmt) == GIMPLE_SWITCH) | |
3be33b6e JJ |
212 | { |
213 | gcc_checking_assert (gsi_stmt (gsi_last_bb (bb)) == stmt); | |
7b5ab0cd | 214 | retval |= cleanup_control_expr_graph (bb, gsi, first_p); |
3be33b6e | 215 | } |
726a989a RB |
216 | else if (gimple_code (stmt) == GIMPLE_GOTO |
217 | && TREE_CODE (gimple_goto_dest (stmt)) == ADDR_EXPR | |
218 | && (TREE_CODE (TREE_OPERAND (gimple_goto_dest (stmt), 0)) | |
672987e8 | 219 | == LABEL_DECL)) |
c9784e6d | 220 | { |
726a989a RB |
221 | /* If we had a computed goto which has a compile-time determinable |
222 | destination, then we can eliminate the goto. */ | |
672987e8 ZD |
223 | edge e; |
224 | tree label; | |
225 | edge_iterator ei; | |
226 | basic_block target_block; | |
c9784e6d | 227 | |
3be33b6e | 228 | gcc_checking_assert (gsi_stmt (gsi_last_bb (bb)) == stmt); |
672987e8 ZD |
229 | /* First look at all the outgoing edges. Delete any outgoing |
230 | edges which do not go to the right block. For the one | |
231 | edge which goes to the right block, fix up its flags. */ | |
726a989a | 232 | label = TREE_OPERAND (gimple_goto_dest (stmt), 0); |
672987e8 ZD |
233 | target_block = label_to_block (label); |
234 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) | |
c9784e6d | 235 | { |
672987e8 ZD |
236 | if (e->dest != target_block) |
237 | remove_edge_and_dominated_blocks (e); | |
238 | else | |
c9784e6d | 239 | { |
672987e8 ZD |
240 | /* Turn off the EDGE_ABNORMAL flag. */ |
241 | e->flags &= ~EDGE_ABNORMAL; | |
c9784e6d | 242 | |
672987e8 ZD |
243 | /* And set EDGE_FALLTHRU. */ |
244 | e->flags |= EDGE_FALLTHRU; | |
245 | ei_next (&ei); | |
246 | } | |
c9784e6d KH |
247 | } |
248 | ||
672987e8 ZD |
249 | bitmap_set_bit (cfgcleanup_altered_bbs, bb->index); |
250 | bitmap_set_bit (cfgcleanup_altered_bbs, target_block->index); | |
251 | ||
252 | /* Remove the GOTO_EXPR as it is not needed. The CFG has all the | |
253 | relevant information we need. */ | |
726a989a | 254 | gsi_remove (&gsi, true); |
672987e8 | 255 | retval = true; |
c9784e6d | 256 | } |
672987e8 ZD |
257 | |
258 | /* Check for indirect calls that have been turned into | |
259 | noreturn calls. */ | |
726a989a | 260 | else if (is_gimple_call (stmt) |
3be33b6e JJ |
261 | && gimple_call_noreturn_p (stmt)) |
262 | { | |
263 | /* If there are debug stmts after the noreturn call, remove them | |
264 | now, they should be all unreachable anyway. */ | |
265 | for (gsi_next (&gsi); !gsi_end_p (gsi); ) | |
266 | gsi_remove (&gsi, true); | |
267 | if (remove_fallthru_edge (bb->succs)) | |
268 | retval = true; | |
269 | } | |
672987e8 | 270 | |
c9784e6d KH |
271 | return retval; |
272 | } | |
273 | ||
274 | /* Return true if basic block BB does nothing except pass control | |
275 | flow to another block and that we can safely insert a label at | |
276 | the start of the successor block. | |
277 | ||
278 | As a precondition, we require that BB be not equal to | |
6626665f | 279 | the entry block. */ |
c9784e6d KH |
280 | |
281 | static bool | |
282 | tree_forwarder_block_p (basic_block bb, bool phi_wanted) | |
283 | { | |
726a989a | 284 | gimple_stmt_iterator gsi; |
f99fcb3b | 285 | location_t locus; |
c9784e6d KH |
286 | |
287 | /* BB must have a single outgoing edge. */ | |
288 | if (single_succ_p (bb) != 1 | |
289 | /* If PHI_WANTED is false, BB must not have any PHI nodes. | |
290 | Otherwise, BB must have PHI nodes. */ | |
726a989a | 291 | || gimple_seq_empty_p (phi_nodes (bb)) == phi_wanted |
6626665f | 292 | /* BB may not be a predecessor of the exit block. */ |
fefa31b5 | 293 | || single_succ (bb) == EXIT_BLOCK_PTR_FOR_FN (cfun) |
c9784e6d KH |
294 | /* Nor should this be an infinite loop. */ |
295 | || single_succ (bb) == bb | |
296 | /* BB may not have an abnormal outgoing edge. */ | |
297 | || (single_succ_edge (bb)->flags & EDGE_ABNORMAL)) | |
298 | return false; | |
299 | ||
fefa31b5 | 300 | gcc_checking_assert (bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
c9784e6d | 301 | |
f99fcb3b JJ |
302 | locus = single_succ_edge (bb)->goto_locus; |
303 | ||
1d65f45c RH |
304 | /* There should not be an edge coming from entry, or an EH edge. */ |
305 | { | |
306 | edge_iterator ei; | |
307 | edge e; | |
308 | ||
309 | FOR_EACH_EDGE (e, ei, bb->preds) | |
fefa31b5 | 310 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun) || (e->flags & EDGE_EH)) |
1d65f45c | 311 | return false; |
f99fcb3b JJ |
312 | /* If goto_locus of any of the edges differs, prevent removing |
313 | the forwarder block for -O0. */ | |
314 | else if (optimize == 0 && e->goto_locus != locus) | |
315 | return false; | |
1d65f45c RH |
316 | } |
317 | ||
c9784e6d KH |
318 | /* Now walk through the statements backward. We can ignore labels, |
319 | anything else means this is not a forwarder block. */ | |
726a989a | 320 | for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi)) |
c9784e6d | 321 | { |
355fe088 | 322 | gimple *stmt = gsi_stmt (gsi); |
c9784e6d | 323 | |
726a989a | 324 | switch (gimple_code (stmt)) |
c9784e6d | 325 | { |
726a989a | 326 | case GIMPLE_LABEL: |
538dd0b7 | 327 | if (DECL_NONLOCAL (gimple_label_label (as_a <glabel *> (stmt)))) |
c9784e6d | 328 | return false; |
f99fcb3b JJ |
329 | if (optimize == 0 && gimple_location (stmt) != locus) |
330 | return false; | |
c9784e6d KH |
331 | break; |
332 | ||
b5b8b0ac AO |
333 | /* ??? For now, hope there's a corresponding debug |
334 | assignment at the destination. */ | |
335 | case GIMPLE_DEBUG: | |
336 | break; | |
337 | ||
c9784e6d KH |
338 | default: |
339 | return false; | |
340 | } | |
341 | } | |
342 | ||
c9784e6d KH |
343 | if (current_loops) |
344 | { | |
345 | basic_block dest; | |
a3afdbb8 | 346 | /* Protect loop headers. */ |
ee281008 | 347 | if (bb_loop_header_p (bb)) |
c9784e6d | 348 | return false; |
c9784e6d | 349 | |
a3afdbb8 BC |
350 | dest = EDGE_SUCC (bb, 0)->dest; |
351 | /* Protect loop preheaders and latches if requested. */ | |
c9784e6d | 352 | if (dest->loop_father->header == dest) |
a3afdbb8 | 353 | { |
fba7c564 RB |
354 | if (bb->loop_father == dest->loop_father) |
355 | { | |
356 | if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) | |
357 | return false; | |
358 | /* If bb doesn't have a single predecessor we'd make this | |
359 | loop have multiple latches. Don't do that if that | |
360 | would in turn require disambiguating them. */ | |
361 | return (single_pred_p (bb) | |
362 | || loops_state_satisfies_p | |
363 | (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)); | |
364 | } | |
365 | else if (bb->loop_father == loop_outer (dest->loop_father)) | |
366 | return !loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS); | |
367 | /* Always preserve other edges into loop headers that are | |
368 | not simple latches or preheaders. */ | |
369 | return false; | |
a3afdbb8 | 370 | } |
c9784e6d | 371 | } |
a3afdbb8 | 372 | |
c9784e6d KH |
373 | return true; |
374 | } | |
375 | ||
c9784e6d KH |
376 | /* If all the PHI nodes in DEST have alternatives for E1 and E2 and |
377 | those alternatives are equal in each of the PHI nodes, then return | |
378 | true, else return false. */ | |
379 | ||
380 | static bool | |
381 | phi_alternatives_equal (basic_block dest, edge e1, edge e2) | |
382 | { | |
383 | int n1 = e1->dest_idx; | |
384 | int n2 = e2->dest_idx; | |
538dd0b7 | 385 | gphi_iterator gsi; |
c9784e6d | 386 | |
726a989a | 387 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
c9784e6d | 388 | { |
538dd0b7 | 389 | gphi *phi = gsi.phi (); |
726a989a RB |
390 | tree val1 = gimple_phi_arg_def (phi, n1); |
391 | tree val2 = gimple_phi_arg_def (phi, n2); | |
c9784e6d KH |
392 | |
393 | gcc_assert (val1 != NULL_TREE); | |
394 | gcc_assert (val2 != NULL_TREE); | |
395 | ||
396 | if (!operand_equal_for_phi_arg_p (val1, val2)) | |
397 | return false; | |
398 | } | |
399 | ||
400 | return true; | |
401 | } | |
402 | ||
672987e8 | 403 | /* Removes forwarder block BB. Returns false if this failed. */ |
c9784e6d KH |
404 | |
405 | static bool | |
672987e8 | 406 | remove_forwarder_block (basic_block bb) |
c9784e6d KH |
407 | { |
408 | edge succ = single_succ_edge (bb), e, s; | |
409 | basic_block dest = succ->dest; | |
355fe088 | 410 | gimple *label; |
c9784e6d | 411 | edge_iterator ei; |
726a989a | 412 | gimple_stmt_iterator gsi, gsi_to; |
70235ab9 | 413 | bool can_move_debug_stmts; |
c9784e6d KH |
414 | |
415 | /* We check for infinite loops already in tree_forwarder_block_p. | |
416 | However it may happen that the infinite loop is created | |
417 | afterwards due to removal of forwarders. */ | |
418 | if (dest == bb) | |
419 | return false; | |
420 | ||
28e5ca15 RB |
421 | /* If the destination block consists of a nonlocal label or is a |
422 | EH landing pad, do not merge it. */ | |
c9784e6d | 423 | label = first_stmt (dest); |
538dd0b7 DM |
424 | if (label) |
425 | if (glabel *label_stmt = dyn_cast <glabel *> (label)) | |
426 | if (DECL_NONLOCAL (gimple_label_label (label_stmt)) | |
427 | || EH_LANDING_PAD_NR (gimple_label_label (label_stmt)) != 0) | |
428 | return false; | |
c9784e6d KH |
429 | |
430 | /* If there is an abnormal edge to basic block BB, but not into | |
431 | dest, problems might occur during removal of the phi node at out | |
432 | of ssa due to overlapping live ranges of registers. | |
433 | ||
434 | If there is an abnormal edge in DEST, the problems would occur | |
435 | anyway since cleanup_dead_labels would then merge the labels for | |
436 | two different eh regions, and rest of exception handling code | |
437 | does not like it. | |
438 | ||
439 | So if there is an abnormal edge to BB, proceed only if there is | |
440 | no abnormal edge to DEST and there are no phi nodes in DEST. */ | |
31ff2426 NF |
441 | if (bb_has_abnormal_pred (bb) |
442 | && (bb_has_abnormal_pred (dest) | |
1197e789 RG |
443 | || !gimple_seq_empty_p (phi_nodes (dest)))) |
444 | return false; | |
c9784e6d KH |
445 | |
446 | /* If there are phi nodes in DEST, and some of the blocks that are | |
447 | predecessors of BB are also predecessors of DEST, check that the | |
448 | phi node arguments match. */ | |
726a989a | 449 | if (!gimple_seq_empty_p (phi_nodes (dest))) |
c9784e6d KH |
450 | { |
451 | FOR_EACH_EDGE (e, ei, bb->preds) | |
452 | { | |
453 | s = find_edge (e->src, dest); | |
454 | if (!s) | |
455 | continue; | |
456 | ||
457 | if (!phi_alternatives_equal (dest, succ, s)) | |
458 | return false; | |
459 | } | |
460 | } | |
461 | ||
dc764d10 | 462 | can_move_debug_stmts = MAY_HAVE_DEBUG_STMTS && single_pred_p (dest); |
70235ab9 | 463 | |
fba7c564 RB |
464 | basic_block pred = NULL; |
465 | if (single_pred_p (bb)) | |
466 | pred = single_pred (bb); | |
467 | ||
c9784e6d KH |
468 | /* Redirect the edges. */ |
469 | for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) | |
470 | { | |
672987e8 ZD |
471 | bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index); |
472 | ||
c9784e6d KH |
473 | if (e->flags & EDGE_ABNORMAL) |
474 | { | |
475 | /* If there is an abnormal edge, redirect it anyway, and | |
476 | move the labels to the new block to make it legal. */ | |
477 | s = redirect_edge_succ_nodup (e, dest); | |
478 | } | |
479 | else | |
480 | s = redirect_edge_and_branch (e, dest); | |
481 | ||
482 | if (s == e) | |
483 | { | |
484 | /* Create arguments for the phi nodes, since the edge was not | |
485 | here before. */ | |
538dd0b7 DM |
486 | for (gphi_iterator psi = gsi_start_phis (dest); |
487 | !gsi_end_p (psi); | |
488 | gsi_next (&psi)) | |
726a989a | 489 | { |
538dd0b7 | 490 | gphi *phi = psi.phi (); |
f5045c96 | 491 | source_location l = gimple_phi_arg_location_from_edge (phi, succ); |
2724573f RB |
492 | tree def = gimple_phi_arg_def (phi, succ->dest_idx); |
493 | add_phi_arg (phi, unshare_expr (def), s, l); | |
726a989a | 494 | } |
c9784e6d | 495 | } |
c9784e6d KH |
496 | } |
497 | ||
1197e789 RG |
498 | /* Move nonlocal labels and computed goto targets as well as user |
499 | defined labels and labels with an EH landing pad number to the | |
500 | new block, so that the redirection of the abnormal edges works, | |
501 | jump targets end up in a sane place and debug information for | |
502 | labels is retained. */ | |
503 | gsi_to = gsi_start_bb (dest); | |
504 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) | |
505 | { | |
506 | tree decl; | |
507 | label = gsi_stmt (gsi); | |
508 | if (is_gimple_debug (label)) | |
509 | break; | |
538dd0b7 | 510 | decl = gimple_label_label (as_a <glabel *> (label)); |
1197e789 RG |
511 | if (EH_LANDING_PAD_NR (decl) != 0 |
512 | || DECL_NONLOCAL (decl) | |
513 | || FORCED_LABEL (decl) | |
514 | || !DECL_ARTIFICIAL (decl)) | |
515 | { | |
516 | gsi_remove (&gsi, false); | |
517 | gsi_insert_before (&gsi_to, label, GSI_SAME_STMT); | |
518 | } | |
519 | else | |
520 | gsi_next (&gsi); | |
521 | } | |
522 | ||
dc764d10 | 523 | /* Move debug statements if the destination has a single predecessor. */ |
70235ab9 | 524 | if (can_move_debug_stmts) |
c9784e6d | 525 | { |
1197e789 RG |
526 | gsi_to = gsi_after_labels (dest); |
527 | for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); ) | |
c9784e6d | 528 | { |
355fe088 | 529 | gimple *debug = gsi_stmt (gsi); |
70235ab9 | 530 | if (!is_gimple_debug (debug)) |
1197e789 | 531 | break; |
726a989a | 532 | gsi_remove (&gsi, false); |
70235ab9 | 533 | gsi_insert_before (&gsi_to, debug, GSI_SAME_STMT); |
c9784e6d KH |
534 | } |
535 | } | |
536 | ||
672987e8 ZD |
537 | bitmap_set_bit (cfgcleanup_altered_bbs, dest->index); |
538 | ||
c9784e6d KH |
539 | /* Update the dominators. */ |
540 | if (dom_info_available_p (CDI_DOMINATORS)) | |
541 | { | |
542 | basic_block dom, dombb, domdest; | |
543 | ||
544 | dombb = get_immediate_dominator (CDI_DOMINATORS, bb); | |
545 | domdest = get_immediate_dominator (CDI_DOMINATORS, dest); | |
546 | if (domdest == bb) | |
547 | { | |
548 | /* Shortcut to avoid calling (relatively expensive) | |
549 | nearest_common_dominator unless necessary. */ | |
550 | dom = dombb; | |
551 | } | |
552 | else | |
553 | dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb); | |
554 | ||
555 | set_immediate_dominator (CDI_DOMINATORS, dest, dom); | |
556 | } | |
557 | ||
a3afdbb8 BC |
558 | /* Adjust latch infomation of BB's parent loop as otherwise |
559 | the cfg hook has a hard time not to kill the loop. */ | |
560 | if (current_loops && bb->loop_father->latch == bb) | |
fba7c564 | 561 | bb->loop_father->latch = pred; |
a3afdbb8 | 562 | |
c9784e6d KH |
563 | /* And kill the forwarder block. */ |
564 | delete_basic_block (bb); | |
565 | ||
566 | return true; | |
567 | } | |
568 | ||
bed18fbd RB |
569 | /* STMT is a call that has been discovered noreturn. Split the |
570 | block to prepare fixing up the CFG and remove LHS. | |
571 | Return true if cleanup-cfg needs to run. */ | |
566d09ef JH |
572 | |
573 | bool | |
355fe088 | 574 | fixup_noreturn_call (gimple *stmt) |
566d09ef JH |
575 | { |
576 | basic_block bb = gimple_bb (stmt); | |
bed18fbd | 577 | bool changed = false; |
566d09ef JH |
578 | |
579 | if (gimple_call_builtin_p (stmt, BUILT_IN_RETURN)) | |
580 | return false; | |
581 | ||
582 | /* First split basic block if stmt is not last. */ | |
583 | if (stmt != gsi_stmt (gsi_last_bb (bb))) | |
c83ee180 JJ |
584 | { |
585 | if (stmt == gsi_stmt (gsi_last_nondebug_bb (bb))) | |
586 | { | |
587 | /* Don't split if there are only debug stmts | |
588 | after stmt, that can result in -fcompare-debug | |
589 | failures. Remove the debug stmts instead, | |
590 | they should be all unreachable anyway. */ | |
591 | gimple_stmt_iterator gsi = gsi_for_stmt (stmt); | |
592 | for (gsi_next (&gsi); !gsi_end_p (gsi); ) | |
593 | gsi_remove (&gsi, true); | |
594 | } | |
595 | else | |
bed18fbd RB |
596 | { |
597 | split_block (bb, stmt); | |
598 | changed = true; | |
599 | } | |
c83ee180 | 600 | } |
566d09ef | 601 | |
e6a54b01 EB |
602 | /* If there is an LHS, remove it, but only if its type has fixed size. |
603 | The LHS will need to be recreated during RTL expansion and creating | |
45177337 | 604 | temporaries of variable-sized types is not supported. Also don't |
458a1cd0 JJ |
605 | do this with TREE_ADDRESSABLE types, as assign_temp will abort. |
606 | Drop LHS regardless of TREE_ADDRESSABLE, if the function call | |
607 | has been changed into a call that does not return a value, like | |
608 | __builtin_unreachable or __cxa_pure_virtual. */ | |
2f1b0141 | 609 | tree lhs = gimple_call_lhs (stmt); |
458a1cd0 JJ |
610 | if (lhs |
611 | && (should_remove_lhs_p (lhs) | |
612 | || VOID_TYPE_P (TREE_TYPE (gimple_call_fntype (stmt))))) | |
566d09ef | 613 | { |
566d09ef | 614 | gimple_call_set_lhs (stmt, NULL_TREE); |
02d635a2 | 615 | |
2f1b0141 EB |
616 | /* We need to fix up the SSA name to avoid checking errors. */ |
617 | if (TREE_CODE (lhs) == SSA_NAME) | |
566d09ef | 618 | { |
b731b390 | 619 | tree new_var = create_tmp_reg (TREE_TYPE (lhs)); |
2f1b0141 EB |
620 | SET_SSA_NAME_VAR_OR_IDENTIFIER (lhs, new_var); |
621 | SSA_NAME_DEF_STMT (lhs) = gimple_build_nop (); | |
622 | set_ssa_default_def (cfun, new_var, lhs); | |
566d09ef | 623 | } |
2f1b0141 | 624 | |
566d09ef | 625 | update_stmt (stmt); |
566d09ef | 626 | } |
2f1b0141 | 627 | |
2a5671ee | 628 | /* Mark the call as altering control flow. */ |
bed18fbd RB |
629 | if (!gimple_call_ctrl_altering_p (stmt)) |
630 | { | |
631 | gimple_call_set_ctrl_altering (stmt, true); | |
632 | changed = true; | |
633 | } | |
2a5671ee | 634 | |
bed18fbd | 635 | return changed; |
566d09ef JH |
636 | } |
637 | ||
638 | ||
672987e8 ZD |
639 | /* Tries to cleanup cfg in basic block BB. Returns true if anything |
640 | changes. */ | |
c9784e6d | 641 | |
89e80dd4 | 642 | static bool |
672987e8 | 643 | cleanup_tree_cfg_bb (basic_block bb) |
c9784e6d | 644 | { |
f99fcb3b | 645 | if (tree_forwarder_block_p (bb, false) |
672987e8 ZD |
646 | && remove_forwarder_block (bb)) |
647 | return true; | |
c9784e6d | 648 | |
50bf47fd RB |
649 | /* If there is a merge opportunity with the predecessor |
650 | do nothing now but wait until we process the predecessor. | |
651 | This happens when we visit BBs in a non-optimal order and | |
652 | avoids quadratic behavior with adjusting stmts BB pointer. */ | |
653 | if (single_pred_p (bb) | |
654 | && can_merge_blocks_p (single_pred (bb), bb)) | |
655 | /* But make sure we _do_ visit it. When we remove unreachable paths | |
656 | ending in a backedge we fail to mark the destinations predecessors | |
657 | as changed. */ | |
658 | bitmap_set_bit (cfgcleanup_altered_bbs, single_pred (bb)->index); | |
659 | ||
89e80dd4 DN |
660 | /* Merging the blocks may create new opportunities for folding |
661 | conditional branches (due to the elimination of single-valued PHI | |
662 | nodes). */ | |
50bf47fd RB |
663 | else if (single_succ_p (bb) |
664 | && can_merge_blocks_p (bb, single_succ (bb))) | |
672987e8 | 665 | { |
50bf47fd RB |
666 | merge_blocks (bb, single_succ (bb)); |
667 | return true; | |
672987e8 ZD |
668 | } |
669 | ||
3810ff24 | 670 | return false; |
672987e8 ZD |
671 | } |
672 | ||
673 | /* Iterate the cfg cleanups, while anything changes. */ | |
674 | ||
675 | static bool | |
676 | cleanup_tree_cfg_1 (void) | |
677 | { | |
678 | bool retval = false; | |
679 | basic_block bb; | |
680 | unsigned i, n; | |
681 | ||
672987e8 ZD |
682 | /* Prepare the worklists of altered blocks. */ |
683 | cfgcleanup_altered_bbs = BITMAP_ALLOC (NULL); | |
684 | ||
685 | /* During forwarder block cleanup, we may redirect edges out of | |
686 | SWITCH_EXPRs, which can get expensive. So we want to enable | |
687 | recording of edge to CASE_LABEL_EXPR. */ | |
688 | start_recording_case_labels (); | |
89e80dd4 | 689 | |
3810ff24 | 690 | /* We cannot use FOR_EACH_BB_FN for the BB iterations below |
672987e8 | 691 | since the basic blocks may get removed. */ |
3810ff24 RB |
692 | |
693 | /* Start by iterating over all basic blocks looking for edge removal | |
694 | opportunities. Do this first because incoming SSA form may be | |
695 | invalid and we want to avoid performing SSA related tasks such | |
696 | as propgating out a PHI node during BB merging in that state. */ | |
697 | n = last_basic_block_for_fn (cfun); | |
698 | for (i = NUM_FIXED_BLOCKS; i < n; i++) | |
699 | { | |
700 | bb = BASIC_BLOCK_FOR_FN (cfun, i); | |
701 | if (bb) | |
7b5ab0cd | 702 | retval |= cleanup_control_flow_bb (bb, true); |
3810ff24 RB |
703 | } |
704 | ||
705 | /* After doing the above SSA form should be valid (or an update SSA | |
706 | should be required). */ | |
707 | ||
708 | /* Continue by iterating over all basic blocks looking for BB merging | |
709 | opportunities. */ | |
8b1c6fd7 | 710 | n = last_basic_block_for_fn (cfun); |
672987e8 ZD |
711 | for (i = NUM_FIXED_BLOCKS; i < n; i++) |
712 | { | |
06e28de2 | 713 | bb = BASIC_BLOCK_FOR_FN (cfun, i); |
672987e8 | 714 | if (bb) |
2a5671ee | 715 | retval |= cleanup_tree_cfg_bb (bb); |
672987e8 ZD |
716 | } |
717 | ||
718 | /* Now process the altered blocks, as long as any are available. */ | |
719 | while (!bitmap_empty_p (cfgcleanup_altered_bbs)) | |
720 | { | |
721 | i = bitmap_first_set_bit (cfgcleanup_altered_bbs); | |
722 | bitmap_clear_bit (cfgcleanup_altered_bbs, i); | |
723 | if (i < NUM_FIXED_BLOCKS) | |
724 | continue; | |
725 | ||
06e28de2 | 726 | bb = BASIC_BLOCK_FOR_FN (cfun, i); |
672987e8 ZD |
727 | if (!bb) |
728 | continue; | |
729 | ||
7b5ab0cd | 730 | retval |= cleanup_control_flow_bb (bb, false); |
672987e8 | 731 | retval |= cleanup_tree_cfg_bb (bb); |
672987e8 | 732 | } |
b8698a0f | 733 | |
672987e8 ZD |
734 | end_recording_case_labels (); |
735 | BITMAP_FREE (cfgcleanup_altered_bbs); | |
89e80dd4 DN |
736 | return retval; |
737 | } | |
738 | ||
739 | ||
e3594cb3 DN |
740 | /* Remove unreachable blocks and other miscellaneous clean up work. |
741 | Return true if the flowgraph was modified, false otherwise. */ | |
89e80dd4 | 742 | |
592c303d ZD |
743 | static bool |
744 | cleanup_tree_cfg_noloop (void) | |
89e80dd4 | 745 | { |
672987e8 | 746 | bool changed; |
89e80dd4 DN |
747 | |
748 | timevar_push (TV_TREE_CLEANUP_CFG); | |
749 | ||
e3594cb3 | 750 | /* Iterate until there are no more cleanups left to do. If any |
672987e8 ZD |
751 | iteration changed the flowgraph, set CHANGED to true. |
752 | ||
753 | If dominance information is available, there cannot be any unreachable | |
754 | blocks. */ | |
2b28c07a | 755 | if (!dom_info_available_p (CDI_DOMINATORS)) |
e3594cb3 | 756 | { |
672987e8 ZD |
757 | changed = delete_unreachable_blocks (); |
758 | calculate_dominance_info (CDI_DOMINATORS); | |
e3594cb3 | 759 | } |
672987e8 | 760 | else |
30251f7a | 761 | { |
b2b29377 | 762 | checking_verify_dominators (CDI_DOMINATORS); |
30251f7a ZD |
763 | changed = false; |
764 | } | |
c9784e6d | 765 | |
672987e8 ZD |
766 | changed |= cleanup_tree_cfg_1 (); |
767 | ||
2b28c07a | 768 | gcc_assert (dom_info_available_p (CDI_DOMINATORS)); |
c9784e6d KH |
769 | compact_blocks (); |
770 | ||
b2b29377 | 771 | checking_verify_flow_info (); |
89e80dd4 | 772 | |
c9784e6d | 773 | timevar_pop (TV_TREE_CLEANUP_CFG); |
89e80dd4 | 774 | |
592c303d | 775 | if (changed && current_loops) |
f87000d0 | 776 | loops_state_set (LOOPS_NEED_FIXUP); |
592c303d | 777 | |
e3594cb3 | 778 | return changed; |
c9784e6d KH |
779 | } |
780 | ||
592c303d | 781 | /* Repairs loop structures. */ |
c9784e6d | 782 | |
592c303d ZD |
783 | static void |
784 | repair_loop_structures (void) | |
c9784e6d | 785 | { |
a222c01a | 786 | bitmap changed_bbs; |
8e89b5b5 | 787 | unsigned n_new_loops; |
a222c01a | 788 | |
cc360b36 SB |
789 | calculate_dominance_info (CDI_DOMINATORS); |
790 | ||
a222c01a MM |
791 | timevar_push (TV_REPAIR_LOOPS); |
792 | changed_bbs = BITMAP_ALLOC (NULL); | |
8e89b5b5 | 793 | n_new_loops = fix_loop_structure (changed_bbs); |
c9784e6d | 794 | |
592c303d ZD |
795 | /* This usually does nothing. But sometimes parts of cfg that originally |
796 | were inside a loop get out of it due to edge removal (since they | |
8e89b5b5 RB |
797 | become unreachable by back edges from latch). Also a former |
798 | irreducible loop can become reducible - in this case force a full | |
799 | rewrite into loop-closed SSA form. */ | |
f87000d0 | 800 | if (loops_state_satisfies_p (LOOP_CLOSED_SSA)) |
8e89b5b5 RB |
801 | rewrite_into_loop_closed_ssa (n_new_loops ? NULL : changed_bbs, |
802 | TODO_update_ssa); | |
c9784e6d | 803 | |
592c303d | 804 | BITMAP_FREE (changed_bbs); |
c9784e6d | 805 | |
b2b29377 | 806 | checking_verify_loop_structure (); |
592c303d ZD |
807 | scev_reset (); |
808 | ||
a222c01a | 809 | timevar_pop (TV_REPAIR_LOOPS); |
592c303d ZD |
810 | } |
811 | ||
812 | /* Cleanup cfg and repair loop structures. */ | |
813 | ||
814 | bool | |
815 | cleanup_tree_cfg (void) | |
816 | { | |
817 | bool changed = cleanup_tree_cfg_noloop (); | |
818 | ||
819 | if (current_loops != NULL | |
f87000d0 | 820 | && loops_state_satisfies_p (LOOPS_NEED_FIXUP)) |
592c303d ZD |
821 | repair_loop_structures (); |
822 | ||
1994bfea | 823 | return changed; |
c9784e6d KH |
824 | } |
825 | ||
a9e0d843 RB |
826 | /* Tries to merge the PHI nodes at BB into those at BB's sole successor. |
827 | Returns true if successful. */ | |
c9784e6d | 828 | |
a9e0d843 | 829 | static bool |
c9784e6d KH |
830 | remove_forwarder_block_with_phi (basic_block bb) |
831 | { | |
832 | edge succ = single_succ_edge (bb); | |
833 | basic_block dest = succ->dest; | |
355fe088 | 834 | gimple *label; |
c9784e6d KH |
835 | basic_block dombb, domdest, dom; |
836 | ||
837 | /* We check for infinite loops already in tree_forwarder_block_p. | |
838 | However it may happen that the infinite loop is created | |
839 | afterwards due to removal of forwarders. */ | |
840 | if (dest == bb) | |
a9e0d843 | 841 | return false; |
f3127685 JL |
842 | |
843 | /* Removal of forwarders may expose new natural loops and thus | |
844 | a block may turn into a loop header. */ | |
845 | if (current_loops && bb_loop_header_p (bb)) | |
846 | return false; | |
c9784e6d KH |
847 | |
848 | /* If the destination block consists of a nonlocal label, do not | |
849 | merge it. */ | |
850 | label = first_stmt (dest); | |
538dd0b7 DM |
851 | if (label) |
852 | if (glabel *label_stmt = dyn_cast <glabel *> (label)) | |
853 | if (DECL_NONLOCAL (gimple_label_label (label_stmt))) | |
854 | return false; | |
c9784e6d | 855 | |
d731ee04 BC |
856 | /* Record BB's single pred in case we need to update the father |
857 | loop's latch information later. */ | |
858 | basic_block pred = NULL; | |
859 | if (single_pred_p (bb)) | |
860 | pred = single_pred (bb); | |
861 | ||
c9784e6d KH |
862 | /* Redirect each incoming edge to BB to DEST. */ |
863 | while (EDGE_COUNT (bb->preds) > 0) | |
864 | { | |
865 | edge e = EDGE_PRED (bb, 0), s; | |
538dd0b7 | 866 | gphi_iterator gsi; |
c9784e6d KH |
867 | |
868 | s = find_edge (e->src, dest); | |
869 | if (s) | |
870 | { | |
871 | /* We already have an edge S from E->src to DEST. If S and | |
872 | E->dest's sole successor edge have the same PHI arguments | |
873 | at DEST, redirect S to DEST. */ | |
874 | if (phi_alternatives_equal (dest, s, succ)) | |
875 | { | |
876 | e = redirect_edge_and_branch (e, dest); | |
ea7e6d5a | 877 | redirect_edge_var_map_clear (e); |
c9784e6d KH |
878 | continue; |
879 | } | |
880 | ||
881 | /* PHI arguments are different. Create a forwarder block by | |
882 | splitting E so that we can merge PHI arguments on E to | |
883 | DEST. */ | |
884 | e = single_succ_edge (split_edge (e)); | |
885 | } | |
886 | ||
887 | s = redirect_edge_and_branch (e, dest); | |
888 | ||
889 | /* redirect_edge_and_branch must not create a new edge. */ | |
890 | gcc_assert (s == e); | |
891 | ||
892 | /* Add to the PHI nodes at DEST each PHI argument removed at the | |
893 | destination of E. */ | |
726a989a RB |
894 | for (gsi = gsi_start_phis (dest); |
895 | !gsi_end_p (gsi); | |
896 | gsi_next (&gsi)) | |
c9784e6d | 897 | { |
538dd0b7 | 898 | gphi *phi = gsi.phi (); |
726a989a | 899 | tree def = gimple_phi_arg_def (phi, succ->dest_idx); |
f5045c96 | 900 | source_location locus = gimple_phi_arg_location_from_edge (phi, succ); |
c9784e6d KH |
901 | |
902 | if (TREE_CODE (def) == SSA_NAME) | |
903 | { | |
c9784e6d KH |
904 | /* If DEF is one of the results of PHI nodes removed during |
905 | redirection, replace it with the PHI argument that used | |
906 | to be on E. */ | |
b787e7a2 TS |
907 | vec<edge_var_map> *head = redirect_edge_var_map_vector (e); |
908 | size_t length = head ? head->length () : 0; | |
909 | for (size_t i = 0; i < length; i++) | |
c9784e6d | 910 | { |
b787e7a2 | 911 | edge_var_map *vm = &(*head)[i]; |
ea7e6d5a AH |
912 | tree old_arg = redirect_edge_var_map_result (vm); |
913 | tree new_arg = redirect_edge_var_map_def (vm); | |
c9784e6d KH |
914 | |
915 | if (def == old_arg) | |
916 | { | |
917 | def = new_arg; | |
f5045c96 | 918 | locus = redirect_edge_var_map_location (vm); |
c9784e6d KH |
919 | break; |
920 | } | |
921 | } | |
922 | } | |
923 | ||
9e227d60 | 924 | add_phi_arg (phi, def, s, locus); |
c9784e6d KH |
925 | } |
926 | ||
ea7e6d5a | 927 | redirect_edge_var_map_clear (e); |
c9784e6d KH |
928 | } |
929 | ||
930 | /* Update the dominators. */ | |
931 | dombb = get_immediate_dominator (CDI_DOMINATORS, bb); | |
932 | domdest = get_immediate_dominator (CDI_DOMINATORS, dest); | |
933 | if (domdest == bb) | |
934 | { | |
935 | /* Shortcut to avoid calling (relatively expensive) | |
936 | nearest_common_dominator unless necessary. */ | |
937 | dom = dombb; | |
938 | } | |
939 | else | |
940 | dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb); | |
941 | ||
942 | set_immediate_dominator (CDI_DOMINATORS, dest, dom); | |
943 | ||
d731ee04 BC |
944 | /* Adjust latch infomation of BB's parent loop as otherwise |
945 | the cfg hook has a hard time not to kill the loop. */ | |
946 | if (current_loops && bb->loop_father->latch == bb) | |
947 | bb->loop_father->latch = pred; | |
948 | ||
c9784e6d KH |
949 | /* Remove BB since all of BB's incoming edges have been redirected |
950 | to DEST. */ | |
951 | delete_basic_block (bb); | |
a9e0d843 RB |
952 | |
953 | return true; | |
c9784e6d KH |
954 | } |
955 | ||
956 | /* This pass merges PHI nodes if one feeds into another. For example, | |
957 | suppose we have the following: | |
958 | ||
959 | goto <bb 9> (<L9>); | |
960 | ||
961 | <L8>:; | |
962 | tem_17 = foo (); | |
963 | ||
964 | # tem_6 = PHI <tem_17(8), tem_23(7)>; | |
965 | <L9>:; | |
966 | ||
967 | # tem_3 = PHI <tem_6(9), tem_2(5)>; | |
968 | <L10>:; | |
969 | ||
970 | Then we merge the first PHI node into the second one like so: | |
971 | ||
972 | goto <bb 9> (<L10>); | |
973 | ||
974 | <L8>:; | |
975 | tem_17 = foo (); | |
976 | ||
977 | # tem_3 = PHI <tem_23(7), tem_2(5), tem_17(8)>; | |
978 | <L10>:; | |
979 | */ | |
980 | ||
be55bfe6 TS |
981 | namespace { |
982 | ||
983 | const pass_data pass_data_merge_phi = | |
984 | { | |
985 | GIMPLE_PASS, /* type */ | |
986 | "mergephi", /* name */ | |
987 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
988 | TV_TREE_MERGE_PHI, /* tv_id */ |
989 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
990 | 0, /* properties_provided */ | |
991 | 0, /* properties_destroyed */ | |
992 | 0, /* todo_flags_start */ | |
3bea341f | 993 | 0, /* todo_flags_finish */ |
be55bfe6 TS |
994 | }; |
995 | ||
996 | class pass_merge_phi : public gimple_opt_pass | |
c9784e6d | 997 | { |
be55bfe6 TS |
998 | public: |
999 | pass_merge_phi (gcc::context *ctxt) | |
1000 | : gimple_opt_pass (pass_data_merge_phi, ctxt) | |
1001 | {} | |
1002 | ||
1003 | /* opt_pass methods: */ | |
1004 | opt_pass * clone () { return new pass_merge_phi (m_ctxt); } | |
1005 | virtual unsigned int execute (function *); | |
1006 | ||
1007 | }; // class pass_merge_phi | |
1008 | ||
1009 | unsigned int | |
1010 | pass_merge_phi::execute (function *fun) | |
1011 | { | |
1012 | basic_block *worklist = XNEWVEC (basic_block, n_basic_blocks_for_fn (fun)); | |
c9784e6d KH |
1013 | basic_block *current = worklist; |
1014 | basic_block bb; | |
1015 | ||
1016 | calculate_dominance_info (CDI_DOMINATORS); | |
1017 | ||
1018 | /* Find all PHI nodes that we may be able to merge. */ | |
be55bfe6 | 1019 | FOR_EACH_BB_FN (bb, fun) |
c9784e6d KH |
1020 | { |
1021 | basic_block dest; | |
1022 | ||
1023 | /* Look for a forwarder block with PHI nodes. */ | |
1024 | if (!tree_forwarder_block_p (bb, true)) | |
1025 | continue; | |
1026 | ||
1027 | dest = single_succ (bb); | |
1028 | ||
1029 | /* We have to feed into another basic block with PHI | |
1030 | nodes. */ | |
8eacd016 | 1031 | if (gimple_seq_empty_p (phi_nodes (dest)) |
c9784e6d KH |
1032 | /* We don't want to deal with a basic block with |
1033 | abnormal edges. */ | |
31ff2426 | 1034 | || bb_has_abnormal_pred (bb)) |
c9784e6d KH |
1035 | continue; |
1036 | ||
1037 | if (!dominated_by_p (CDI_DOMINATORS, dest, bb)) | |
1038 | { | |
1039 | /* If BB does not dominate DEST, then the PHI nodes at | |
1040 | DEST must be the only users of the results of the PHI | |
1041 | nodes at BB. */ | |
1042 | *current++ = bb; | |
1043 | } | |
ea65cd37 JL |
1044 | else |
1045 | { | |
538dd0b7 | 1046 | gphi_iterator gsi; |
338b5886 | 1047 | unsigned int dest_idx = single_succ_edge (bb)->dest_idx; |
ea65cd37 JL |
1048 | |
1049 | /* BB dominates DEST. There may be many users of the PHI | |
1050 | nodes in BB. However, there is still a trivial case we | |
1051 | can handle. If the result of every PHI in BB is used | |
1052 | only by a PHI in DEST, then we can trivially merge the | |
1053 | PHI nodes from BB into DEST. */ | |
726a989a RB |
1054 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
1055 | gsi_next (&gsi)) | |
ea65cd37 | 1056 | { |
538dd0b7 | 1057 | gphi *phi = gsi.phi (); |
726a989a | 1058 | tree result = gimple_phi_result (phi); |
ea65cd37 | 1059 | use_operand_p imm_use; |
355fe088 | 1060 | gimple *use_stmt; |
ea65cd37 JL |
1061 | |
1062 | /* If the PHI's result is never used, then we can just | |
1063 | ignore it. */ | |
bfc646bf | 1064 | if (has_zero_uses (result)) |
ea65cd37 JL |
1065 | continue; |
1066 | ||
1067 | /* Get the single use of the result of this PHI node. */ | |
1068 | if (!single_imm_use (result, &imm_use, &use_stmt) | |
726a989a RB |
1069 | || gimple_code (use_stmt) != GIMPLE_PHI |
1070 | || gimple_bb (use_stmt) != dest | |
1071 | || gimple_phi_arg_def (use_stmt, dest_idx) != result) | |
ea65cd37 JL |
1072 | break; |
1073 | } | |
1074 | ||
c0220ea4 | 1075 | /* If the loop above iterated through all the PHI nodes |
ea65cd37 | 1076 | in BB, then we can merge the PHIs from BB into DEST. */ |
726a989a | 1077 | if (gsi_end_p (gsi)) |
ea65cd37 JL |
1078 | *current++ = bb; |
1079 | } | |
c9784e6d KH |
1080 | } |
1081 | ||
1082 | /* Now let's drain WORKLIST. */ | |
a9e0d843 | 1083 | bool changed = false; |
c9784e6d KH |
1084 | while (current != worklist) |
1085 | { | |
1086 | bb = *--current; | |
a9e0d843 | 1087 | changed |= remove_forwarder_block_with_phi (bb); |
c9784e6d | 1088 | } |
c9784e6d | 1089 | free (worklist); |
a9e0d843 RB |
1090 | |
1091 | /* Removing forwarder blocks can cause formerly irreducible loops | |
1092 | to become reducible if we merged two entry blocks. */ | |
1093 | if (changed | |
1094 | && current_loops) | |
1095 | loops_state_set (LOOPS_NEED_FIXUP); | |
1096 | ||
c2924966 | 1097 | return 0; |
c9784e6d KH |
1098 | } |
1099 | ||
27a4cd48 DM |
1100 | } // anon namespace |
1101 | ||
1102 | gimple_opt_pass * | |
1103 | make_pass_merge_phi (gcc::context *ctxt) | |
1104 | { | |
1105 | return new pass_merge_phi (ctxt); | |
1106 | } | |
4484a35a AM |
1107 | |
1108 | /* Pass: cleanup the CFG just before expanding trees to RTL. | |
1109 | This is just a round of label cleanups and case node grouping | |
1110 | because after the tree optimizers have run such cleanups may | |
1111 | be necessary. */ | |
1112 | ||
1113 | static unsigned int | |
1114 | execute_cleanup_cfg_post_optimizing (void) | |
1115 | { | |
2a5671ee | 1116 | unsigned int todo = execute_fixup_cfg (); |
4484a35a | 1117 | if (cleanup_tree_cfg ()) |
2a5671ee RB |
1118 | { |
1119 | todo &= ~TODO_cleanup_cfg; | |
1120 | todo |= TODO_update_ssa; | |
1121 | } | |
4484a35a AM |
1122 | maybe_remove_unreachable_handlers (); |
1123 | cleanup_dead_labels (); | |
1124 | group_case_labels (); | |
1125 | if ((flag_compare_debug_opt || flag_compare_debug) | |
1126 | && flag_dump_final_insns) | |
1127 | { | |
1128 | FILE *final_output = fopen (flag_dump_final_insns, "a"); | |
1129 | ||
1130 | if (!final_output) | |
1131 | { | |
1132 | error ("could not open final insn dump file %qs: %m", | |
1133 | flag_dump_final_insns); | |
1134 | flag_dump_final_insns = NULL; | |
1135 | } | |
1136 | else | |
1137 | { | |
1138 | int save_unnumbered = flag_dump_unnumbered; | |
1139 | int save_noaddr = flag_dump_noaddr; | |
1140 | ||
1141 | flag_dump_noaddr = flag_dump_unnumbered = 1; | |
1142 | fprintf (final_output, "\n"); | |
1143 | dump_enumerated_decls (final_output, dump_flags | TDF_NOUID); | |
1144 | flag_dump_noaddr = save_noaddr; | |
1145 | flag_dump_unnumbered = save_unnumbered; | |
1146 | if (fclose (final_output)) | |
1147 | { | |
1148 | error ("could not close final insn dump file %qs: %m", | |
1149 | flag_dump_final_insns); | |
1150 | flag_dump_final_insns = NULL; | |
1151 | } | |
1152 | } | |
1153 | } | |
1154 | return todo; | |
1155 | } | |
1156 | ||
1157 | namespace { | |
1158 | ||
1159 | const pass_data pass_data_cleanup_cfg_post_optimizing = | |
1160 | { | |
1161 | GIMPLE_PASS, /* type */ | |
1162 | "optimized", /* name */ | |
1163 | OPTGROUP_NONE, /* optinfo_flags */ | |
4484a35a AM |
1164 | TV_TREE_CLEANUP_CFG, /* tv_id */ |
1165 | PROP_cfg, /* properties_required */ | |
1166 | 0, /* properties_provided */ | |
1167 | 0, /* properties_destroyed */ | |
1168 | 0, /* todo_flags_start */ | |
1169 | TODO_remove_unused_locals, /* todo_flags_finish */ | |
1170 | }; | |
1171 | ||
1172 | class pass_cleanup_cfg_post_optimizing : public gimple_opt_pass | |
1173 | { | |
1174 | public: | |
1175 | pass_cleanup_cfg_post_optimizing (gcc::context *ctxt) | |
1176 | : gimple_opt_pass (pass_data_cleanup_cfg_post_optimizing, ctxt) | |
1177 | {} | |
1178 | ||
1179 | /* opt_pass methods: */ | |
be55bfe6 TS |
1180 | virtual unsigned int execute (function *) |
1181 | { | |
1182 | return execute_cleanup_cfg_post_optimizing (); | |
1183 | } | |
4484a35a AM |
1184 | |
1185 | }; // class pass_cleanup_cfg_post_optimizing | |
1186 | ||
1187 | } // anon namespace | |
1188 | ||
1189 | gimple_opt_pass * | |
1190 | make_pass_cleanup_cfg_post_optimizing (gcc::context *ctxt) | |
1191 | { | |
1192 | return new pass_cleanup_cfg_post_optimizing (ctxt); | |
1193 | } | |
1194 | ||
1195 |