]>
Commit | Line | Data |
---|---|---|
c9784e6d | 1 | /* CFG cleanup for trees. |
5624e564 | 2 | Copyright (C) 2001-2015 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" | |
23 | #include "tm.h" | |
40e23961 MC |
24 | #include "alias.h" |
25 | #include "symtab.h" | |
c9784e6d | 26 | #include "tree.h" |
40e23961 | 27 | #include "fold-const.h" |
c9784e6d | 28 | #include "tm_p.h" |
60393bbc | 29 | #include "predict.h" |
83685514 | 30 | #include "hard-reg-set.h" |
c9784e6d | 31 | #include "function.h" |
60393bbc AM |
32 | #include "dominance.h" |
33 | #include "cfg.h" | |
34 | #include "cfganal.h" | |
35 | #include "cfgcleanup.h" | |
36 | #include "basic-block.h" | |
37 | #include "diagnostic-core.h" | |
38 | #include "flags.h" | |
c9784e6d | 39 | #include "langhooks.h" |
2fb9a547 AM |
40 | #include "tree-ssa-alias.h" |
41 | #include "internal-fn.h" | |
42 | #include "tree-eh.h" | |
43 | #include "gimple-expr.h" | |
18f429e2 | 44 | #include "gimple.h" |
45b0be94 | 45 | #include "gimplify.h" |
5be5c238 | 46 | #include "gimple-iterator.h" |
442b4905 AM |
47 | #include "gimple-ssa.h" |
48 | #include "tree-cfg.h" | |
49 | #include "tree-phinodes.h" | |
50 | #include "ssa-iterators.h" | |
d8a2d370 | 51 | #include "stringpool.h" |
442b4905 | 52 | #include "tree-ssanames.h" |
e28030cf | 53 | #include "tree-ssa-loop-manip.h" |
36566b39 | 54 | #include "rtl.h" |
36566b39 PK |
55 | #include "insn-config.h" |
56 | #include "expmed.h" | |
57 | #include "dojump.h" | |
58 | #include "explow.h" | |
59 | #include "calls.h" | |
60 | #include "emit-rtl.h" | |
61 | #include "varasm.h" | |
62 | #include "stmt.h" | |
d8a2d370 | 63 | #include "expr.h" |
442b4905 | 64 | #include "tree-dfa.h" |
7a300452 | 65 | #include "tree-ssa.h" |
c9784e6d | 66 | #include "tree-pass.h" |
c9784e6d KH |
67 | #include "except.h" |
68 | #include "cfgloop.h" | |
c9784e6d | 69 | #include "tree-ssa-propagate.h" |
17684618 | 70 | #include "tree-scalar-evolution.h" |
c9784e6d | 71 | |
672987e8 ZD |
72 | /* The set of blocks in that at least one of the following changes happened: |
73 | -- the statement at the end of the block was changed | |
74 | -- the block was newly created | |
75 | -- the set of the predecessors of the block changed | |
76 | -- the set of the successors of the block changed | |
77 | ??? Maybe we could track these changes separately, since they determine | |
78 | what cleanups it makes sense to try on the block. */ | |
79 | bitmap cfgcleanup_altered_bbs; | |
80 | ||
c9784e6d KH |
81 | /* Remove any fallthru edge from EV. Return true if an edge was removed. */ |
82 | ||
83 | static bool | |
9771b263 | 84 | remove_fallthru_edge (vec<edge, va_gc> *ev) |
c9784e6d KH |
85 | { |
86 | edge_iterator ei; | |
87 | edge e; | |
88 | ||
89 | FOR_EACH_EDGE (e, ei, ev) | |
90 | if ((e->flags & EDGE_FALLTHRU) != 0) | |
91 | { | |
0107dca2 RB |
92 | if (e->flags & EDGE_COMPLEX) |
93 | e->flags &= ~EDGE_FALLTHRU; | |
94 | else | |
95 | remove_edge_and_dominated_blocks (e); | |
c9784e6d KH |
96 | return true; |
97 | } | |
98 | return false; | |
99 | } | |
100 | ||
726a989a | 101 | |
c9784e6d KH |
102 | /* Disconnect an unreachable block in the control expression starting |
103 | at block BB. */ | |
104 | ||
105 | static bool | |
726a989a | 106 | cleanup_control_expr_graph (basic_block bb, gimple_stmt_iterator gsi) |
c9784e6d KH |
107 | { |
108 | edge taken_edge; | |
109 | bool retval = false; | |
726a989a RB |
110 | gimple stmt = gsi_stmt (gsi); |
111 | tree val; | |
c9784e6d KH |
112 | |
113 | if (!single_succ_p (bb)) | |
114 | { | |
115 | edge e; | |
116 | edge_iterator ei; | |
6ac01510 | 117 | bool warned; |
37530014 | 118 | location_t loc; |
6ac01510 ILT |
119 | |
120 | fold_defer_overflow_warnings (); | |
37530014 RG |
121 | loc = gimple_location (stmt); |
122 | switch (gimple_code (stmt)) | |
123 | { | |
124 | case GIMPLE_COND: | |
fea4ea73 EB |
125 | val = fold_binary_loc (loc, gimple_cond_code (stmt), |
126 | boolean_type_node, | |
127 | gimple_cond_lhs (stmt), | |
128 | gimple_cond_rhs (stmt)); | |
129 | break; | |
37530014 RG |
130 | |
131 | case GIMPLE_SWITCH: | |
538dd0b7 | 132 | val = gimple_switch_index (as_a <gswitch *> (stmt)); |
37530014 RG |
133 | break; |
134 | ||
135 | default: | |
136 | val = NULL_TREE; | |
137 | } | |
c9784e6d KH |
138 | taken_edge = find_taken_edge (bb, val); |
139 | if (!taken_edge) | |
6ac01510 ILT |
140 | { |
141 | fold_undefer_and_ignore_overflow_warnings (); | |
142 | return false; | |
143 | } | |
c9784e6d KH |
144 | |
145 | /* Remove all the edges except the one that is always executed. */ | |
6ac01510 | 146 | warned = false; |
c9784e6d KH |
147 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) |
148 | { | |
149 | if (e != taken_edge) | |
150 | { | |
6ac01510 ILT |
151 | if (!warned) |
152 | { | |
153 | fold_undefer_overflow_warnings | |
726a989a | 154 | (true, stmt, WARN_STRICT_OVERFLOW_CONDITIONAL); |
6ac01510 ILT |
155 | warned = true; |
156 | } | |
157 | ||
c9784e6d KH |
158 | taken_edge->probability += e->probability; |
159 | taken_edge->count += e->count; | |
672987e8 | 160 | remove_edge_and_dominated_blocks (e); |
c9784e6d KH |
161 | retval = true; |
162 | } | |
163 | else | |
164 | ei_next (&ei); | |
165 | } | |
6ac01510 ILT |
166 | if (!warned) |
167 | fold_undefer_and_ignore_overflow_warnings (); | |
c9784e6d KH |
168 | if (taken_edge->probability > REG_BR_PROB_BASE) |
169 | taken_edge->probability = REG_BR_PROB_BASE; | |
170 | } | |
171 | else | |
172 | taken_edge = single_succ_edge (bb); | |
173 | ||
672987e8 | 174 | bitmap_set_bit (cfgcleanup_altered_bbs, bb->index); |
726a989a | 175 | gsi_remove (&gsi, true); |
c9784e6d KH |
176 | taken_edge->flags = EDGE_FALLTHRU; |
177 | ||
c9784e6d KH |
178 | return retval; |
179 | } | |
180 | ||
58041fe6 MJ |
181 | /* Cleanup the GF_CALL_CTRL_ALTERING flag according to |
182 | to updated gimple_call_flags. */ | |
183 | ||
184 | static void | |
185 | cleanup_call_ctrl_altering_flag (gimple bb_end) | |
186 | { | |
187 | if (!is_gimple_call (bb_end) | |
188 | || !gimple_call_ctrl_altering_p (bb_end)) | |
189 | return; | |
190 | ||
191 | int flags = gimple_call_flags (bb_end); | |
192 | if (((flags & (ECF_CONST | ECF_PURE)) | |
193 | && !(flags & ECF_LOOPING_CONST_OR_PURE)) | |
194 | || (flags & ECF_LEAF)) | |
195 | gimple_call_set_ctrl_altering (bb_end, false); | |
196 | } | |
197 | ||
672987e8 ZD |
198 | /* Try to remove superfluous control structures in basic block BB. Returns |
199 | true if anything changes. */ | |
c9784e6d KH |
200 | |
201 | static bool | |
672987e8 | 202 | cleanup_control_flow_bb (basic_block bb) |
c9784e6d | 203 | { |
726a989a | 204 | gimple_stmt_iterator gsi; |
c9784e6d | 205 | bool retval = false; |
726a989a | 206 | gimple stmt; |
c9784e6d | 207 | |
672987e8 ZD |
208 | /* If the last statement of the block could throw and now cannot, |
209 | we need to prune cfg. */ | |
726a989a | 210 | retval |= gimple_purge_dead_eh_edges (bb); |
672987e8 | 211 | |
726a989a RB |
212 | gsi = gsi_last_bb (bb); |
213 | if (gsi_end_p (gsi)) | |
672987e8 ZD |
214 | return retval; |
215 | ||
726a989a | 216 | stmt = gsi_stmt (gsi); |
672987e8 | 217 | |
58041fe6 MJ |
218 | /* Try to cleanup ctrl altering flag for call which ends bb. */ |
219 | cleanup_call_ctrl_altering_flag (stmt); | |
220 | ||
726a989a RB |
221 | if (gimple_code (stmt) == GIMPLE_COND |
222 | || gimple_code (stmt) == GIMPLE_SWITCH) | |
223 | retval |= cleanup_control_expr_graph (bb, gsi); | |
224 | else if (gimple_code (stmt) == GIMPLE_GOTO | |
225 | && TREE_CODE (gimple_goto_dest (stmt)) == ADDR_EXPR | |
226 | && (TREE_CODE (TREE_OPERAND (gimple_goto_dest (stmt), 0)) | |
672987e8 | 227 | == LABEL_DECL)) |
c9784e6d | 228 | { |
726a989a RB |
229 | /* If we had a computed goto which has a compile-time determinable |
230 | destination, then we can eliminate the goto. */ | |
672987e8 ZD |
231 | edge e; |
232 | tree label; | |
233 | edge_iterator ei; | |
234 | basic_block target_block; | |
c9784e6d | 235 | |
672987e8 ZD |
236 | /* First look at all the outgoing edges. Delete any outgoing |
237 | edges which do not go to the right block. For the one | |
238 | edge which goes to the right block, fix up its flags. */ | |
726a989a | 239 | label = TREE_OPERAND (gimple_goto_dest (stmt), 0); |
672987e8 ZD |
240 | target_block = label_to_block (label); |
241 | for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) | |
c9784e6d | 242 | { |
672987e8 ZD |
243 | if (e->dest != target_block) |
244 | remove_edge_and_dominated_blocks (e); | |
245 | else | |
c9784e6d | 246 | { |
672987e8 ZD |
247 | /* Turn off the EDGE_ABNORMAL flag. */ |
248 | e->flags &= ~EDGE_ABNORMAL; | |
c9784e6d | 249 | |
672987e8 ZD |
250 | /* And set EDGE_FALLTHRU. */ |
251 | e->flags |= EDGE_FALLTHRU; | |
252 | ei_next (&ei); | |
253 | } | |
c9784e6d KH |
254 | } |
255 | ||
672987e8 ZD |
256 | bitmap_set_bit (cfgcleanup_altered_bbs, bb->index); |
257 | bitmap_set_bit (cfgcleanup_altered_bbs, target_block->index); | |
258 | ||
259 | /* Remove the GOTO_EXPR as it is not needed. The CFG has all the | |
260 | relevant information we need. */ | |
726a989a | 261 | gsi_remove (&gsi, true); |
672987e8 | 262 | retval = true; |
c9784e6d | 263 | } |
672987e8 ZD |
264 | |
265 | /* Check for indirect calls that have been turned into | |
266 | noreturn calls. */ | |
726a989a RB |
267 | else if (is_gimple_call (stmt) |
268 | && gimple_call_noreturn_p (stmt) | |
269 | && remove_fallthru_edge (bb->succs)) | |
672987e8 ZD |
270 | retval = true; |
271 | ||
c9784e6d KH |
272 | return retval; |
273 | } | |
274 | ||
275 | /* Return true if basic block BB does nothing except pass control | |
276 | flow to another block and that we can safely insert a label at | |
277 | the start of the successor block. | |
278 | ||
279 | As a precondition, we require that BB be not equal to | |
6626665f | 280 | the entry block. */ |
c9784e6d KH |
281 | |
282 | static bool | |
283 | tree_forwarder_block_p (basic_block bb, bool phi_wanted) | |
284 | { | |
726a989a | 285 | gimple_stmt_iterator gsi; |
f99fcb3b | 286 | location_t locus; |
c9784e6d KH |
287 | |
288 | /* BB must have a single outgoing edge. */ | |
289 | if (single_succ_p (bb) != 1 | |
290 | /* If PHI_WANTED is false, BB must not have any PHI nodes. | |
291 | Otherwise, BB must have PHI nodes. */ | |
726a989a | 292 | || gimple_seq_empty_p (phi_nodes (bb)) == phi_wanted |
6626665f | 293 | /* BB may not be a predecessor of the exit block. */ |
fefa31b5 | 294 | || single_succ (bb) == EXIT_BLOCK_PTR_FOR_FN (cfun) |
c9784e6d KH |
295 | /* Nor should this be an infinite loop. */ |
296 | || single_succ (bb) == bb | |
297 | /* BB may not have an abnormal outgoing edge. */ | |
298 | || (single_succ_edge (bb)->flags & EDGE_ABNORMAL)) | |
299 | return false; | |
300 | ||
fefa31b5 | 301 | gcc_checking_assert (bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
c9784e6d | 302 | |
f99fcb3b JJ |
303 | locus = single_succ_edge (bb)->goto_locus; |
304 | ||
1d65f45c RH |
305 | /* There should not be an edge coming from entry, or an EH edge. */ |
306 | { | |
307 | edge_iterator ei; | |
308 | edge e; | |
309 | ||
310 | FOR_EACH_EDGE (e, ei, bb->preds) | |
fefa31b5 | 311 | if (e->src == ENTRY_BLOCK_PTR_FOR_FN (cfun) || (e->flags & EDGE_EH)) |
1d65f45c | 312 | return false; |
f99fcb3b JJ |
313 | /* If goto_locus of any of the edges differs, prevent removing |
314 | the forwarder block for -O0. */ | |
315 | else if (optimize == 0 && e->goto_locus != locus) | |
316 | return false; | |
1d65f45c RH |
317 | } |
318 | ||
c9784e6d KH |
319 | /* Now walk through the statements backward. We can ignore labels, |
320 | anything else means this is not a forwarder block. */ | |
726a989a | 321 | for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi)) |
c9784e6d | 322 | { |
726a989a | 323 | gimple stmt = gsi_stmt (gsi); |
c9784e6d | 324 | |
726a989a | 325 | switch (gimple_code (stmt)) |
c9784e6d | 326 | { |
726a989a | 327 | case GIMPLE_LABEL: |
538dd0b7 | 328 | if (DECL_NONLOCAL (gimple_label_label (as_a <glabel *> (stmt)))) |
c9784e6d | 329 | return false; |
f99fcb3b JJ |
330 | if (optimize == 0 && gimple_location (stmt) != locus) |
331 | return false; | |
c9784e6d KH |
332 | break; |
333 | ||
b5b8b0ac AO |
334 | /* ??? For now, hope there's a corresponding debug |
335 | assignment at the destination. */ | |
336 | case GIMPLE_DEBUG: | |
337 | break; | |
338 | ||
c9784e6d KH |
339 | default: |
340 | return false; | |
341 | } | |
342 | } | |
343 | ||
c9784e6d KH |
344 | if (current_loops) |
345 | { | |
346 | basic_block dest; | |
a3afdbb8 | 347 | /* Protect loop headers. */ |
c9784e6d KH |
348 | if (bb->loop_father->header == bb) |
349 | return false; | |
c9784e6d | 350 | |
a3afdbb8 BC |
351 | dest = EDGE_SUCC (bb, 0)->dest; |
352 | /* Protect loop preheaders and latches if requested. */ | |
c9784e6d | 353 | if (dest->loop_father->header == dest) |
a3afdbb8 | 354 | { |
fba7c564 RB |
355 | if (bb->loop_father == dest->loop_father) |
356 | { | |
357 | if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) | |
358 | return false; | |
359 | /* If bb doesn't have a single predecessor we'd make this | |
360 | loop have multiple latches. Don't do that if that | |
361 | would in turn require disambiguating them. */ | |
362 | return (single_pred_p (bb) | |
363 | || loops_state_satisfies_p | |
364 | (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)); | |
365 | } | |
366 | else if (bb->loop_father == loop_outer (dest->loop_father)) | |
367 | return !loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS); | |
368 | /* Always preserve other edges into loop headers that are | |
369 | not simple latches or preheaders. */ | |
370 | return false; | |
a3afdbb8 | 371 | } |
c9784e6d | 372 | } |
a3afdbb8 | 373 | |
c9784e6d KH |
374 | return true; |
375 | } | |
376 | ||
c9784e6d KH |
377 | /* If all the PHI nodes in DEST have alternatives for E1 and E2 and |
378 | those alternatives are equal in each of the PHI nodes, then return | |
379 | true, else return false. */ | |
380 | ||
381 | static bool | |
382 | phi_alternatives_equal (basic_block dest, edge e1, edge e2) | |
383 | { | |
384 | int n1 = e1->dest_idx; | |
385 | int n2 = e2->dest_idx; | |
538dd0b7 | 386 | gphi_iterator gsi; |
c9784e6d | 387 | |
726a989a | 388 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
c9784e6d | 389 | { |
538dd0b7 | 390 | gphi *phi = gsi.phi (); |
726a989a RB |
391 | tree val1 = gimple_phi_arg_def (phi, n1); |
392 | tree val2 = gimple_phi_arg_def (phi, n2); | |
c9784e6d KH |
393 | |
394 | gcc_assert (val1 != NULL_TREE); | |
395 | gcc_assert (val2 != NULL_TREE); | |
396 | ||
397 | if (!operand_equal_for_phi_arg_p (val1, val2)) | |
398 | return false; | |
399 | } | |
400 | ||
401 | return true; | |
402 | } | |
403 | ||
672987e8 | 404 | /* Removes forwarder block BB. Returns false if this failed. */ |
c9784e6d KH |
405 | |
406 | static bool | |
672987e8 | 407 | remove_forwarder_block (basic_block bb) |
c9784e6d KH |
408 | { |
409 | edge succ = single_succ_edge (bb), e, s; | |
410 | basic_block dest = succ->dest; | |
726a989a | 411 | gimple label; |
c9784e6d | 412 | edge_iterator ei; |
726a989a | 413 | gimple_stmt_iterator gsi, gsi_to; |
70235ab9 | 414 | bool can_move_debug_stmts; |
c9784e6d KH |
415 | |
416 | /* We check for infinite loops already in tree_forwarder_block_p. | |
417 | However it may happen that the infinite loop is created | |
418 | afterwards due to removal of forwarders. */ | |
419 | if (dest == bb) | |
420 | return false; | |
421 | ||
28e5ca15 RB |
422 | /* If the destination block consists of a nonlocal label or is a |
423 | EH landing pad, do not merge it. */ | |
c9784e6d | 424 | label = first_stmt (dest); |
538dd0b7 DM |
425 | if (label) |
426 | if (glabel *label_stmt = dyn_cast <glabel *> (label)) | |
427 | if (DECL_NONLOCAL (gimple_label_label (label_stmt)) | |
428 | || EH_LANDING_PAD_NR (gimple_label_label (label_stmt)) != 0) | |
429 | return false; | |
c9784e6d KH |
430 | |
431 | /* If there is an abnormal edge to basic block BB, but not into | |
432 | dest, problems might occur during removal of the phi node at out | |
433 | of ssa due to overlapping live ranges of registers. | |
434 | ||
435 | If there is an abnormal edge in DEST, the problems would occur | |
436 | anyway since cleanup_dead_labels would then merge the labels for | |
437 | two different eh regions, and rest of exception handling code | |
438 | does not like it. | |
439 | ||
440 | So if there is an abnormal edge to BB, proceed only if there is | |
441 | no abnormal edge to DEST and there are no phi nodes in DEST. */ | |
31ff2426 NF |
442 | if (bb_has_abnormal_pred (bb) |
443 | && (bb_has_abnormal_pred (dest) | |
1197e789 RG |
444 | || !gimple_seq_empty_p (phi_nodes (dest)))) |
445 | return false; | |
c9784e6d KH |
446 | |
447 | /* If there are phi nodes in DEST, and some of the blocks that are | |
448 | predecessors of BB are also predecessors of DEST, check that the | |
449 | phi node arguments match. */ | |
726a989a | 450 | if (!gimple_seq_empty_p (phi_nodes (dest))) |
c9784e6d KH |
451 | { |
452 | FOR_EACH_EDGE (e, ei, bb->preds) | |
453 | { | |
454 | s = find_edge (e->src, dest); | |
455 | if (!s) | |
456 | continue; | |
457 | ||
458 | if (!phi_alternatives_equal (dest, succ, s)) | |
459 | return false; | |
460 | } | |
461 | } | |
462 | ||
dc764d10 | 463 | can_move_debug_stmts = MAY_HAVE_DEBUG_STMTS && single_pred_p (dest); |
70235ab9 | 464 | |
fba7c564 RB |
465 | basic_block pred = NULL; |
466 | if (single_pred_p (bb)) | |
467 | pred = single_pred (bb); | |
468 | ||
c9784e6d KH |
469 | /* Redirect the edges. */ |
470 | for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) | |
471 | { | |
672987e8 ZD |
472 | bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index); |
473 | ||
c9784e6d KH |
474 | if (e->flags & EDGE_ABNORMAL) |
475 | { | |
476 | /* If there is an abnormal edge, redirect it anyway, and | |
477 | move the labels to the new block to make it legal. */ | |
478 | s = redirect_edge_succ_nodup (e, dest); | |
479 | } | |
480 | else | |
481 | s = redirect_edge_and_branch (e, dest); | |
482 | ||
483 | if (s == e) | |
484 | { | |
485 | /* Create arguments for the phi nodes, since the edge was not | |
486 | here before. */ | |
538dd0b7 DM |
487 | for (gphi_iterator psi = gsi_start_phis (dest); |
488 | !gsi_end_p (psi); | |
489 | gsi_next (&psi)) | |
726a989a | 490 | { |
538dd0b7 | 491 | gphi *phi = psi.phi (); |
f5045c96 | 492 | source_location l = gimple_phi_arg_location_from_edge (phi, succ); |
2724573f RB |
493 | tree def = gimple_phi_arg_def (phi, succ->dest_idx); |
494 | add_phi_arg (phi, unshare_expr (def), s, l); | |
726a989a | 495 | } |
c9784e6d | 496 | } |
c9784e6d KH |
497 | } |
498 | ||
1197e789 RG |
499 | /* Move nonlocal labels and computed goto targets as well as user |
500 | defined labels and labels with an EH landing pad number to the | |
501 | new block, so that the redirection of the abnormal edges works, | |
502 | jump targets end up in a sane place and debug information for | |
503 | labels is retained. */ | |
504 | gsi_to = gsi_start_bb (dest); | |
505 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) | |
506 | { | |
507 | tree decl; | |
508 | label = gsi_stmt (gsi); | |
509 | if (is_gimple_debug (label)) | |
510 | break; | |
538dd0b7 | 511 | decl = gimple_label_label (as_a <glabel *> (label)); |
1197e789 RG |
512 | if (EH_LANDING_PAD_NR (decl) != 0 |
513 | || DECL_NONLOCAL (decl) | |
514 | || FORCED_LABEL (decl) | |
515 | || !DECL_ARTIFICIAL (decl)) | |
516 | { | |
517 | gsi_remove (&gsi, false); | |
518 | gsi_insert_before (&gsi_to, label, GSI_SAME_STMT); | |
519 | } | |
520 | else | |
521 | gsi_next (&gsi); | |
522 | } | |
523 | ||
dc764d10 | 524 | /* Move debug statements if the destination has a single predecessor. */ |
70235ab9 | 525 | if (can_move_debug_stmts) |
c9784e6d | 526 | { |
1197e789 RG |
527 | gsi_to = gsi_after_labels (dest); |
528 | for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); ) | |
c9784e6d | 529 | { |
70235ab9 JJ |
530 | gimple debug = gsi_stmt (gsi); |
531 | if (!is_gimple_debug (debug)) | |
1197e789 | 532 | break; |
726a989a | 533 | gsi_remove (&gsi, false); |
70235ab9 | 534 | gsi_insert_before (&gsi_to, debug, GSI_SAME_STMT); |
c9784e6d KH |
535 | } |
536 | } | |
537 | ||
672987e8 ZD |
538 | bitmap_set_bit (cfgcleanup_altered_bbs, dest->index); |
539 | ||
c9784e6d KH |
540 | /* Update the dominators. */ |
541 | if (dom_info_available_p (CDI_DOMINATORS)) | |
542 | { | |
543 | basic_block dom, dombb, domdest; | |
544 | ||
545 | dombb = get_immediate_dominator (CDI_DOMINATORS, bb); | |
546 | domdest = get_immediate_dominator (CDI_DOMINATORS, dest); | |
547 | if (domdest == bb) | |
548 | { | |
549 | /* Shortcut to avoid calling (relatively expensive) | |
550 | nearest_common_dominator unless necessary. */ | |
551 | dom = dombb; | |
552 | } | |
553 | else | |
554 | dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb); | |
555 | ||
556 | set_immediate_dominator (CDI_DOMINATORS, dest, dom); | |
557 | } | |
558 | ||
a3afdbb8 BC |
559 | /* Adjust latch infomation of BB's parent loop as otherwise |
560 | the cfg hook has a hard time not to kill the loop. */ | |
561 | if (current_loops && bb->loop_father->latch == bb) | |
fba7c564 | 562 | bb->loop_father->latch = pred; |
a3afdbb8 | 563 | |
c9784e6d KH |
564 | /* And kill the forwarder block. */ |
565 | delete_basic_block (bb); | |
566 | ||
567 | return true; | |
568 | } | |
569 | ||
bed18fbd RB |
570 | /* STMT is a call that has been discovered noreturn. Split the |
571 | block to prepare fixing up the CFG and remove LHS. | |
572 | Return true if cleanup-cfg needs to run. */ | |
566d09ef JH |
573 | |
574 | bool | |
575 | fixup_noreturn_call (gimple stmt) | |
576 | { | |
577 | basic_block bb = gimple_bb (stmt); | |
bed18fbd | 578 | bool changed = false; |
566d09ef JH |
579 | |
580 | if (gimple_call_builtin_p (stmt, BUILT_IN_RETURN)) | |
581 | return false; | |
582 | ||
583 | /* First split basic block if stmt is not last. */ | |
584 | if (stmt != gsi_stmt (gsi_last_bb (bb))) | |
c83ee180 JJ |
585 | { |
586 | if (stmt == gsi_stmt (gsi_last_nondebug_bb (bb))) | |
587 | { | |
588 | /* Don't split if there are only debug stmts | |
589 | after stmt, that can result in -fcompare-debug | |
590 | failures. Remove the debug stmts instead, | |
591 | they should be all unreachable anyway. */ | |
592 | gimple_stmt_iterator gsi = gsi_for_stmt (stmt); | |
593 | for (gsi_next (&gsi); !gsi_end_p (gsi); ) | |
594 | gsi_remove (&gsi, true); | |
595 | } | |
596 | else | |
bed18fbd RB |
597 | { |
598 | split_block (bb, stmt); | |
599 | changed = true; | |
600 | } | |
c83ee180 | 601 | } |
566d09ef | 602 | |
e6a54b01 EB |
603 | /* If there is an LHS, remove it, but only if its type has fixed size. |
604 | The LHS will need to be recreated during RTL expansion and creating | |
605 | temporaries of variable-sized types is not supported. */ | |
2f1b0141 | 606 | tree lhs = gimple_call_lhs (stmt); |
e6a54b01 | 607 | if (lhs && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (lhs))) == INTEGER_CST) |
566d09ef | 608 | { |
566d09ef | 609 | gimple_call_set_lhs (stmt, NULL_TREE); |
02d635a2 | 610 | |
2f1b0141 EB |
611 | /* We need to fix up the SSA name to avoid checking errors. */ |
612 | if (TREE_CODE (lhs) == SSA_NAME) | |
566d09ef | 613 | { |
b731b390 | 614 | tree new_var = create_tmp_reg (TREE_TYPE (lhs)); |
2f1b0141 EB |
615 | SET_SSA_NAME_VAR_OR_IDENTIFIER (lhs, new_var); |
616 | SSA_NAME_DEF_STMT (lhs) = gimple_build_nop (); | |
617 | set_ssa_default_def (cfun, new_var, lhs); | |
566d09ef | 618 | } |
2f1b0141 | 619 | |
566d09ef | 620 | update_stmt (stmt); |
566d09ef | 621 | } |
2f1b0141 | 622 | |
2a5671ee | 623 | /* Mark the call as altering control flow. */ |
bed18fbd RB |
624 | if (!gimple_call_ctrl_altering_p (stmt)) |
625 | { | |
626 | gimple_call_set_ctrl_altering (stmt, true); | |
627 | changed = true; | |
628 | } | |
2a5671ee | 629 | |
bed18fbd | 630 | return changed; |
566d09ef JH |
631 | } |
632 | ||
633 | ||
672987e8 ZD |
634 | /* Tries to cleanup cfg in basic block BB. Returns true if anything |
635 | changes. */ | |
c9784e6d | 636 | |
89e80dd4 | 637 | static bool |
672987e8 | 638 | cleanup_tree_cfg_bb (basic_block bb) |
c9784e6d | 639 | { |
65e7bfe3 | 640 | bool retval = cleanup_control_flow_bb (bb); |
b8698a0f | 641 | |
f99fcb3b | 642 | if (tree_forwarder_block_p (bb, false) |
672987e8 ZD |
643 | && remove_forwarder_block (bb)) |
644 | return true; | |
c9784e6d | 645 | |
89e80dd4 DN |
646 | /* Merging the blocks may create new opportunities for folding |
647 | conditional branches (due to the elimination of single-valued PHI | |
648 | nodes). */ | |
672987e8 ZD |
649 | if (single_succ_p (bb) |
650 | && can_merge_blocks_p (bb, single_succ (bb))) | |
651 | { | |
2aa26a55 RB |
652 | /* If there is a merge opportunity with the predecessor |
653 | do nothing now but wait until we process the predecessor. | |
654 | This happens when we visit BBs in a non-optimal order and | |
655 | avoids quadratic behavior with adjusting stmts BB pointer. */ | |
656 | if (single_pred_p (bb) | |
657 | && can_merge_blocks_p (single_pred (bb), bb)) | |
658 | ; | |
659 | else | |
660 | { | |
661 | merge_blocks (bb, single_succ (bb)); | |
662 | return true; | |
663 | } | |
672987e8 ZD |
664 | } |
665 | ||
666 | return retval; | |
667 | } | |
668 | ||
669 | /* Iterate the cfg cleanups, while anything changes. */ | |
670 | ||
671 | static bool | |
672 | cleanup_tree_cfg_1 (void) | |
673 | { | |
674 | bool retval = false; | |
675 | basic_block bb; | |
676 | unsigned i, n; | |
677 | ||
672987e8 ZD |
678 | /* Prepare the worklists of altered blocks. */ |
679 | cfgcleanup_altered_bbs = BITMAP_ALLOC (NULL); | |
680 | ||
681 | /* During forwarder block cleanup, we may redirect edges out of | |
682 | SWITCH_EXPRs, which can get expensive. So we want to enable | |
683 | recording of edge to CASE_LABEL_EXPR. */ | |
684 | start_recording_case_labels (); | |
89e80dd4 | 685 | |
11cd3bed | 686 | /* Start by iterating over all basic blocks. We cannot use FOR_EACH_BB_FN, |
672987e8 | 687 | since the basic blocks may get removed. */ |
8b1c6fd7 | 688 | n = last_basic_block_for_fn (cfun); |
672987e8 ZD |
689 | for (i = NUM_FIXED_BLOCKS; i < n; i++) |
690 | { | |
06e28de2 | 691 | bb = BASIC_BLOCK_FOR_FN (cfun, i); |
672987e8 | 692 | if (bb) |
2a5671ee | 693 | retval |= cleanup_tree_cfg_bb (bb); |
672987e8 ZD |
694 | } |
695 | ||
696 | /* Now process the altered blocks, as long as any are available. */ | |
697 | while (!bitmap_empty_p (cfgcleanup_altered_bbs)) | |
698 | { | |
699 | i = bitmap_first_set_bit (cfgcleanup_altered_bbs); | |
700 | bitmap_clear_bit (cfgcleanup_altered_bbs, i); | |
701 | if (i < NUM_FIXED_BLOCKS) | |
702 | continue; | |
703 | ||
06e28de2 | 704 | bb = BASIC_BLOCK_FOR_FN (cfun, i); |
672987e8 ZD |
705 | if (!bb) |
706 | continue; | |
707 | ||
708 | retval |= cleanup_tree_cfg_bb (bb); | |
672987e8 | 709 | } |
b8698a0f | 710 | |
672987e8 ZD |
711 | end_recording_case_labels (); |
712 | BITMAP_FREE (cfgcleanup_altered_bbs); | |
89e80dd4 DN |
713 | return retval; |
714 | } | |
715 | ||
716 | ||
e3594cb3 DN |
717 | /* Remove unreachable blocks and other miscellaneous clean up work. |
718 | Return true if the flowgraph was modified, false otherwise. */ | |
89e80dd4 | 719 | |
592c303d ZD |
720 | static bool |
721 | cleanup_tree_cfg_noloop (void) | |
89e80dd4 | 722 | { |
672987e8 | 723 | bool changed; |
89e80dd4 DN |
724 | |
725 | timevar_push (TV_TREE_CLEANUP_CFG); | |
726 | ||
e3594cb3 | 727 | /* Iterate until there are no more cleanups left to do. If any |
672987e8 ZD |
728 | iteration changed the flowgraph, set CHANGED to true. |
729 | ||
730 | If dominance information is available, there cannot be any unreachable | |
731 | blocks. */ | |
2b28c07a | 732 | if (!dom_info_available_p (CDI_DOMINATORS)) |
e3594cb3 | 733 | { |
672987e8 ZD |
734 | changed = delete_unreachable_blocks (); |
735 | calculate_dominance_info (CDI_DOMINATORS); | |
e3594cb3 | 736 | } |
672987e8 | 737 | else |
30251f7a ZD |
738 | { |
739 | #ifdef ENABLE_CHECKING | |
740 | verify_dominators (CDI_DOMINATORS); | |
741 | #endif | |
742 | changed = false; | |
743 | } | |
c9784e6d | 744 | |
672987e8 ZD |
745 | changed |= cleanup_tree_cfg_1 (); |
746 | ||
2b28c07a | 747 | gcc_assert (dom_info_available_p (CDI_DOMINATORS)); |
c9784e6d KH |
748 | compact_blocks (); |
749 | ||
750 | #ifdef ENABLE_CHECKING | |
751 | verify_flow_info (); | |
752 | #endif | |
89e80dd4 | 753 | |
c9784e6d | 754 | timevar_pop (TV_TREE_CLEANUP_CFG); |
89e80dd4 | 755 | |
592c303d | 756 | if (changed && current_loops) |
f87000d0 | 757 | loops_state_set (LOOPS_NEED_FIXUP); |
592c303d | 758 | |
e3594cb3 | 759 | return changed; |
c9784e6d KH |
760 | } |
761 | ||
592c303d | 762 | /* Repairs loop structures. */ |
c9784e6d | 763 | |
592c303d ZD |
764 | static void |
765 | repair_loop_structures (void) | |
c9784e6d | 766 | { |
a222c01a | 767 | bitmap changed_bbs; |
8e89b5b5 | 768 | unsigned n_new_loops; |
a222c01a | 769 | |
cc360b36 SB |
770 | calculate_dominance_info (CDI_DOMINATORS); |
771 | ||
a222c01a MM |
772 | timevar_push (TV_REPAIR_LOOPS); |
773 | changed_bbs = BITMAP_ALLOC (NULL); | |
8e89b5b5 | 774 | n_new_loops = fix_loop_structure (changed_bbs); |
c9784e6d | 775 | |
592c303d ZD |
776 | /* This usually does nothing. But sometimes parts of cfg that originally |
777 | were inside a loop get out of it due to edge removal (since they | |
8e89b5b5 RB |
778 | become unreachable by back edges from latch). Also a former |
779 | irreducible loop can become reducible - in this case force a full | |
780 | rewrite into loop-closed SSA form. */ | |
f87000d0 | 781 | if (loops_state_satisfies_p (LOOP_CLOSED_SSA)) |
8e89b5b5 RB |
782 | rewrite_into_loop_closed_ssa (n_new_loops ? NULL : changed_bbs, |
783 | TODO_update_ssa); | |
c9784e6d | 784 | |
592c303d | 785 | BITMAP_FREE (changed_bbs); |
c9784e6d KH |
786 | |
787 | #ifdef ENABLE_CHECKING | |
592c303d | 788 | verify_loop_structure (); |
c9784e6d | 789 | #endif |
592c303d ZD |
790 | scev_reset (); |
791 | ||
a222c01a | 792 | timevar_pop (TV_REPAIR_LOOPS); |
592c303d ZD |
793 | } |
794 | ||
795 | /* Cleanup cfg and repair loop structures. */ | |
796 | ||
797 | bool | |
798 | cleanup_tree_cfg (void) | |
799 | { | |
800 | bool changed = cleanup_tree_cfg_noloop (); | |
801 | ||
802 | if (current_loops != NULL | |
f87000d0 | 803 | && loops_state_satisfies_p (LOOPS_NEED_FIXUP)) |
592c303d ZD |
804 | repair_loop_structures (); |
805 | ||
1994bfea | 806 | return changed; |
c9784e6d KH |
807 | } |
808 | ||
a9e0d843 RB |
809 | /* Tries to merge the PHI nodes at BB into those at BB's sole successor. |
810 | Returns true if successful. */ | |
c9784e6d | 811 | |
a9e0d843 | 812 | static bool |
c9784e6d KH |
813 | remove_forwarder_block_with_phi (basic_block bb) |
814 | { | |
815 | edge succ = single_succ_edge (bb); | |
816 | basic_block dest = succ->dest; | |
726a989a | 817 | gimple label; |
c9784e6d KH |
818 | basic_block dombb, domdest, dom; |
819 | ||
820 | /* We check for infinite loops already in tree_forwarder_block_p. | |
821 | However it may happen that the infinite loop is created | |
822 | afterwards due to removal of forwarders. */ | |
823 | if (dest == bb) | |
a9e0d843 | 824 | return false; |
c9784e6d KH |
825 | |
826 | /* If the destination block consists of a nonlocal label, do not | |
827 | merge it. */ | |
828 | label = first_stmt (dest); | |
538dd0b7 DM |
829 | if (label) |
830 | if (glabel *label_stmt = dyn_cast <glabel *> (label)) | |
831 | if (DECL_NONLOCAL (gimple_label_label (label_stmt))) | |
832 | return false; | |
c9784e6d | 833 | |
d731ee04 BC |
834 | /* Record BB's single pred in case we need to update the father |
835 | loop's latch information later. */ | |
836 | basic_block pred = NULL; | |
837 | if (single_pred_p (bb)) | |
838 | pred = single_pred (bb); | |
839 | ||
c9784e6d KH |
840 | /* Redirect each incoming edge to BB to DEST. */ |
841 | while (EDGE_COUNT (bb->preds) > 0) | |
842 | { | |
843 | edge e = EDGE_PRED (bb, 0), s; | |
538dd0b7 | 844 | gphi_iterator gsi; |
c9784e6d KH |
845 | |
846 | s = find_edge (e->src, dest); | |
847 | if (s) | |
848 | { | |
849 | /* We already have an edge S from E->src to DEST. If S and | |
850 | E->dest's sole successor edge have the same PHI arguments | |
851 | at DEST, redirect S to DEST. */ | |
852 | if (phi_alternatives_equal (dest, s, succ)) | |
853 | { | |
854 | e = redirect_edge_and_branch (e, dest); | |
ea7e6d5a | 855 | redirect_edge_var_map_clear (e); |
c9784e6d KH |
856 | continue; |
857 | } | |
858 | ||
859 | /* PHI arguments are different. Create a forwarder block by | |
860 | splitting E so that we can merge PHI arguments on E to | |
861 | DEST. */ | |
862 | e = single_succ_edge (split_edge (e)); | |
863 | } | |
864 | ||
865 | s = redirect_edge_and_branch (e, dest); | |
866 | ||
867 | /* redirect_edge_and_branch must not create a new edge. */ | |
868 | gcc_assert (s == e); | |
869 | ||
870 | /* Add to the PHI nodes at DEST each PHI argument removed at the | |
871 | destination of E. */ | |
726a989a RB |
872 | for (gsi = gsi_start_phis (dest); |
873 | !gsi_end_p (gsi); | |
874 | gsi_next (&gsi)) | |
c9784e6d | 875 | { |
538dd0b7 | 876 | gphi *phi = gsi.phi (); |
726a989a | 877 | tree def = gimple_phi_arg_def (phi, succ->dest_idx); |
f5045c96 | 878 | source_location locus = gimple_phi_arg_location_from_edge (phi, succ); |
c9784e6d KH |
879 | |
880 | if (TREE_CODE (def) == SSA_NAME) | |
881 | { | |
c9784e6d KH |
882 | /* If DEF is one of the results of PHI nodes removed during |
883 | redirection, replace it with the PHI argument that used | |
884 | to be on E. */ | |
b787e7a2 TS |
885 | vec<edge_var_map> *head = redirect_edge_var_map_vector (e); |
886 | size_t length = head ? head->length () : 0; | |
887 | for (size_t i = 0; i < length; i++) | |
c9784e6d | 888 | { |
b787e7a2 | 889 | edge_var_map *vm = &(*head)[i]; |
ea7e6d5a AH |
890 | tree old_arg = redirect_edge_var_map_result (vm); |
891 | tree new_arg = redirect_edge_var_map_def (vm); | |
c9784e6d KH |
892 | |
893 | if (def == old_arg) | |
894 | { | |
895 | def = new_arg; | |
f5045c96 | 896 | locus = redirect_edge_var_map_location (vm); |
c9784e6d KH |
897 | break; |
898 | } | |
899 | } | |
900 | } | |
901 | ||
9e227d60 | 902 | add_phi_arg (phi, def, s, locus); |
c9784e6d KH |
903 | } |
904 | ||
ea7e6d5a | 905 | redirect_edge_var_map_clear (e); |
c9784e6d KH |
906 | } |
907 | ||
908 | /* Update the dominators. */ | |
909 | dombb = get_immediate_dominator (CDI_DOMINATORS, bb); | |
910 | domdest = get_immediate_dominator (CDI_DOMINATORS, dest); | |
911 | if (domdest == bb) | |
912 | { | |
913 | /* Shortcut to avoid calling (relatively expensive) | |
914 | nearest_common_dominator unless necessary. */ | |
915 | dom = dombb; | |
916 | } | |
917 | else | |
918 | dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb); | |
919 | ||
920 | set_immediate_dominator (CDI_DOMINATORS, dest, dom); | |
921 | ||
d731ee04 BC |
922 | /* Adjust latch infomation of BB's parent loop as otherwise |
923 | the cfg hook has a hard time not to kill the loop. */ | |
924 | if (current_loops && bb->loop_father->latch == bb) | |
925 | bb->loop_father->latch = pred; | |
926 | ||
c9784e6d KH |
927 | /* Remove BB since all of BB's incoming edges have been redirected |
928 | to DEST. */ | |
929 | delete_basic_block (bb); | |
a9e0d843 RB |
930 | |
931 | return true; | |
c9784e6d KH |
932 | } |
933 | ||
934 | /* This pass merges PHI nodes if one feeds into another. For example, | |
935 | suppose we have the following: | |
936 | ||
937 | goto <bb 9> (<L9>); | |
938 | ||
939 | <L8>:; | |
940 | tem_17 = foo (); | |
941 | ||
942 | # tem_6 = PHI <tem_17(8), tem_23(7)>; | |
943 | <L9>:; | |
944 | ||
945 | # tem_3 = PHI <tem_6(9), tem_2(5)>; | |
946 | <L10>:; | |
947 | ||
948 | Then we merge the first PHI node into the second one like so: | |
949 | ||
950 | goto <bb 9> (<L10>); | |
951 | ||
952 | <L8>:; | |
953 | tem_17 = foo (); | |
954 | ||
955 | # tem_3 = PHI <tem_23(7), tem_2(5), tem_17(8)>; | |
956 | <L10>:; | |
957 | */ | |
958 | ||
be55bfe6 TS |
959 | namespace { |
960 | ||
961 | const pass_data pass_data_merge_phi = | |
962 | { | |
963 | GIMPLE_PASS, /* type */ | |
964 | "mergephi", /* name */ | |
965 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
966 | TV_TREE_MERGE_PHI, /* tv_id */ |
967 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
968 | 0, /* properties_provided */ | |
969 | 0, /* properties_destroyed */ | |
970 | 0, /* todo_flags_start */ | |
3bea341f | 971 | 0, /* todo_flags_finish */ |
be55bfe6 TS |
972 | }; |
973 | ||
974 | class pass_merge_phi : public gimple_opt_pass | |
c9784e6d | 975 | { |
be55bfe6 TS |
976 | public: |
977 | pass_merge_phi (gcc::context *ctxt) | |
978 | : gimple_opt_pass (pass_data_merge_phi, ctxt) | |
979 | {} | |
980 | ||
981 | /* opt_pass methods: */ | |
982 | opt_pass * clone () { return new pass_merge_phi (m_ctxt); } | |
983 | virtual unsigned int execute (function *); | |
984 | ||
985 | }; // class pass_merge_phi | |
986 | ||
987 | unsigned int | |
988 | pass_merge_phi::execute (function *fun) | |
989 | { | |
990 | basic_block *worklist = XNEWVEC (basic_block, n_basic_blocks_for_fn (fun)); | |
c9784e6d KH |
991 | basic_block *current = worklist; |
992 | basic_block bb; | |
993 | ||
994 | calculate_dominance_info (CDI_DOMINATORS); | |
995 | ||
996 | /* Find all PHI nodes that we may be able to merge. */ | |
be55bfe6 | 997 | FOR_EACH_BB_FN (bb, fun) |
c9784e6d KH |
998 | { |
999 | basic_block dest; | |
1000 | ||
1001 | /* Look for a forwarder block with PHI nodes. */ | |
1002 | if (!tree_forwarder_block_p (bb, true)) | |
1003 | continue; | |
1004 | ||
1005 | dest = single_succ (bb); | |
1006 | ||
1007 | /* We have to feed into another basic block with PHI | |
1008 | nodes. */ | |
8eacd016 | 1009 | if (gimple_seq_empty_p (phi_nodes (dest)) |
c9784e6d KH |
1010 | /* We don't want to deal with a basic block with |
1011 | abnormal edges. */ | |
31ff2426 | 1012 | || bb_has_abnormal_pred (bb)) |
c9784e6d KH |
1013 | continue; |
1014 | ||
1015 | if (!dominated_by_p (CDI_DOMINATORS, dest, bb)) | |
1016 | { | |
1017 | /* If BB does not dominate DEST, then the PHI nodes at | |
1018 | DEST must be the only users of the results of the PHI | |
1019 | nodes at BB. */ | |
1020 | *current++ = bb; | |
1021 | } | |
ea65cd37 JL |
1022 | else |
1023 | { | |
538dd0b7 | 1024 | gphi_iterator gsi; |
338b5886 | 1025 | unsigned int dest_idx = single_succ_edge (bb)->dest_idx; |
ea65cd37 JL |
1026 | |
1027 | /* BB dominates DEST. There may be many users of the PHI | |
1028 | nodes in BB. However, there is still a trivial case we | |
1029 | can handle. If the result of every PHI in BB is used | |
1030 | only by a PHI in DEST, then we can trivially merge the | |
1031 | PHI nodes from BB into DEST. */ | |
726a989a RB |
1032 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
1033 | gsi_next (&gsi)) | |
ea65cd37 | 1034 | { |
538dd0b7 | 1035 | gphi *phi = gsi.phi (); |
726a989a | 1036 | tree result = gimple_phi_result (phi); |
ea65cd37 | 1037 | use_operand_p imm_use; |
726a989a | 1038 | gimple use_stmt; |
ea65cd37 JL |
1039 | |
1040 | /* If the PHI's result is never used, then we can just | |
1041 | ignore it. */ | |
bfc646bf | 1042 | if (has_zero_uses (result)) |
ea65cd37 JL |
1043 | continue; |
1044 | ||
1045 | /* Get the single use of the result of this PHI node. */ | |
1046 | if (!single_imm_use (result, &imm_use, &use_stmt) | |
726a989a RB |
1047 | || gimple_code (use_stmt) != GIMPLE_PHI |
1048 | || gimple_bb (use_stmt) != dest | |
1049 | || gimple_phi_arg_def (use_stmt, dest_idx) != result) | |
ea65cd37 JL |
1050 | break; |
1051 | } | |
1052 | ||
c0220ea4 | 1053 | /* If the loop above iterated through all the PHI nodes |
ea65cd37 | 1054 | in BB, then we can merge the PHIs from BB into DEST. */ |
726a989a | 1055 | if (gsi_end_p (gsi)) |
ea65cd37 JL |
1056 | *current++ = bb; |
1057 | } | |
c9784e6d KH |
1058 | } |
1059 | ||
1060 | /* Now let's drain WORKLIST. */ | |
a9e0d843 | 1061 | bool changed = false; |
c9784e6d KH |
1062 | while (current != worklist) |
1063 | { | |
1064 | bb = *--current; | |
a9e0d843 | 1065 | changed |= remove_forwarder_block_with_phi (bb); |
c9784e6d | 1066 | } |
c9784e6d | 1067 | free (worklist); |
a9e0d843 RB |
1068 | |
1069 | /* Removing forwarder blocks can cause formerly irreducible loops | |
1070 | to become reducible if we merged two entry blocks. */ | |
1071 | if (changed | |
1072 | && current_loops) | |
1073 | loops_state_set (LOOPS_NEED_FIXUP); | |
1074 | ||
c2924966 | 1075 | return 0; |
c9784e6d KH |
1076 | } |
1077 | ||
27a4cd48 DM |
1078 | } // anon namespace |
1079 | ||
1080 | gimple_opt_pass * | |
1081 | make_pass_merge_phi (gcc::context *ctxt) | |
1082 | { | |
1083 | return new pass_merge_phi (ctxt); | |
1084 | } | |
4484a35a AM |
1085 | |
1086 | /* Pass: cleanup the CFG just before expanding trees to RTL. | |
1087 | This is just a round of label cleanups and case node grouping | |
1088 | because after the tree optimizers have run such cleanups may | |
1089 | be necessary. */ | |
1090 | ||
1091 | static unsigned int | |
1092 | execute_cleanup_cfg_post_optimizing (void) | |
1093 | { | |
2a5671ee | 1094 | unsigned int todo = execute_fixup_cfg (); |
4484a35a | 1095 | if (cleanup_tree_cfg ()) |
2a5671ee RB |
1096 | { |
1097 | todo &= ~TODO_cleanup_cfg; | |
1098 | todo |= TODO_update_ssa; | |
1099 | } | |
4484a35a AM |
1100 | maybe_remove_unreachable_handlers (); |
1101 | cleanup_dead_labels (); | |
1102 | group_case_labels (); | |
1103 | if ((flag_compare_debug_opt || flag_compare_debug) | |
1104 | && flag_dump_final_insns) | |
1105 | { | |
1106 | FILE *final_output = fopen (flag_dump_final_insns, "a"); | |
1107 | ||
1108 | if (!final_output) | |
1109 | { | |
1110 | error ("could not open final insn dump file %qs: %m", | |
1111 | flag_dump_final_insns); | |
1112 | flag_dump_final_insns = NULL; | |
1113 | } | |
1114 | else | |
1115 | { | |
1116 | int save_unnumbered = flag_dump_unnumbered; | |
1117 | int save_noaddr = flag_dump_noaddr; | |
1118 | ||
1119 | flag_dump_noaddr = flag_dump_unnumbered = 1; | |
1120 | fprintf (final_output, "\n"); | |
1121 | dump_enumerated_decls (final_output, dump_flags | TDF_NOUID); | |
1122 | flag_dump_noaddr = save_noaddr; | |
1123 | flag_dump_unnumbered = save_unnumbered; | |
1124 | if (fclose (final_output)) | |
1125 | { | |
1126 | error ("could not close final insn dump file %qs: %m", | |
1127 | flag_dump_final_insns); | |
1128 | flag_dump_final_insns = NULL; | |
1129 | } | |
1130 | } | |
1131 | } | |
1132 | return todo; | |
1133 | } | |
1134 | ||
1135 | namespace { | |
1136 | ||
1137 | const pass_data pass_data_cleanup_cfg_post_optimizing = | |
1138 | { | |
1139 | GIMPLE_PASS, /* type */ | |
1140 | "optimized", /* name */ | |
1141 | OPTGROUP_NONE, /* optinfo_flags */ | |
4484a35a AM |
1142 | TV_TREE_CLEANUP_CFG, /* tv_id */ |
1143 | PROP_cfg, /* properties_required */ | |
1144 | 0, /* properties_provided */ | |
1145 | 0, /* properties_destroyed */ | |
1146 | 0, /* todo_flags_start */ | |
1147 | TODO_remove_unused_locals, /* todo_flags_finish */ | |
1148 | }; | |
1149 | ||
1150 | class pass_cleanup_cfg_post_optimizing : public gimple_opt_pass | |
1151 | { | |
1152 | public: | |
1153 | pass_cleanup_cfg_post_optimizing (gcc::context *ctxt) | |
1154 | : gimple_opt_pass (pass_data_cleanup_cfg_post_optimizing, ctxt) | |
1155 | {} | |
1156 | ||
1157 | /* opt_pass methods: */ | |
be55bfe6 TS |
1158 | virtual unsigned int execute (function *) |
1159 | { | |
1160 | return execute_cleanup_cfg_post_optimizing (); | |
1161 | } | |
4484a35a AM |
1162 | |
1163 | }; // class pass_cleanup_cfg_post_optimizing | |
1164 | ||
1165 | } // anon namespace | |
1166 | ||
1167 | gimple_opt_pass * | |
1168 | make_pass_cleanup_cfg_post_optimizing (gcc::context *ctxt) | |
1169 | { | |
1170 | return new pass_cleanup_cfg_post_optimizing (ctxt); | |
1171 | } | |
1172 | ||
1173 |