Line data Source code
1 : /* SSA Dominator optimizations for trees
2 : Copyright (C) 2001-2026 Free Software Foundation, Inc.
3 : Contributed by Diego Novillo <dnovillo@redhat.com>
4 :
5 : This file is part of GCC.
6 :
7 : GCC is free software; you can redistribute it and/or modify
8 : it under the terms of the GNU General Public License as published by
9 : the Free Software Foundation; either version 3, or (at your option)
10 : any later version.
11 :
12 : GCC is distributed in the hope that it will be useful,
13 : but WITHOUT ANY WARRANTY; without even the implied warranty of
14 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 : GNU General Public License for more details.
16 :
17 : You should have received a copy of the GNU General Public License
18 : along with GCC; see the file COPYING3. If not see
19 : <http://www.gnu.org/licenses/>. */
20 :
21 : #include "config.h"
22 : #include "system.h"
23 : #include "coretypes.h"
24 : #include "backend.h"
25 : #include "tree.h"
26 : #include "gimple.h"
27 : #include "tree-pass.h"
28 : #include "ssa.h"
29 : #include "gimple-pretty-print.h"
30 : #include "fold-const.h"
31 : #include "cfganal.h"
32 : #include "cfgloop.h"
33 : #include "gimple-iterator.h"
34 : #include "gimple-fold.h"
35 : #include "tree-eh.h"
36 : #include "tree-inline.h"
37 : #include "tree-cfg.h"
38 : #include "tree-into-ssa.h"
39 : #include "domwalk.h"
40 : #include "tree-ssa-propagate.h"
41 : #include "tree-ssa-threadupdate.h"
42 : #include "tree-ssa-scopedtables.h"
43 : #include "tree-ssa-threadedge.h"
44 : #include "tree-ssa-dom.h"
45 : #include "tree-cfgcleanup.h"
46 : #include "dbgcnt.h"
47 : #include "alloc-pool.h"
48 : #include "tree-vrp.h"
49 : #include "vr-values.h"
50 : #include "gimple-range.h"
51 : #include "gimple-range-path.h"
52 : #include "alias.h"
53 :
54 : /* This file implements optimizations on the dominator tree. */
55 :
56 : /* Structure for recording edge equivalences.
57 :
58 : Computing and storing the edge equivalences instead of creating
59 : them on-demand can save significant amounts of time, particularly
60 : for pathological cases involving switch statements.
61 :
62 : These structures live for a single iteration of the dominator
63 : optimizer in the edge's AUX field. At the end of an iteration we
64 : free each of these structures. */
65 : class edge_info
66 : {
67 : public:
68 : typedef std::pair <tree, tree> equiv_pair;
69 : edge_info (edge);
70 : ~edge_info ();
71 :
72 : /* Record a simple LHS = RHS equivalence. This may trigger
73 : calls to derive_equivalences. */
74 : void record_simple_equiv (tree, tree);
75 :
76 : /* If traversing this edge creates simple equivalences, we store
77 : them as LHS/RHS pairs within this vector. */
78 : vec<equiv_pair> simple_equivalences;
79 :
80 : /* Traversing an edge may also indicate one or more particular conditions
81 : are true or false. */
82 : vec<cond_equivalence> cond_equivalences;
83 :
84 : private:
85 : /* Derive equivalences by walking the use-def chains. */
86 : void derive_equivalences (tree, tree, int);
87 : };
88 :
89 : /* Track whether or not we have changed the control flow graph. */
90 : static bool cfg_altered;
91 :
92 : /* Bitmap of blocks that have had EH statements cleaned. We should
93 : remove their dead edges eventually. */
94 : static bitmap need_eh_cleanup;
95 : static vec<gimple *> need_noreturn_fixup;
96 :
97 : /* Statistics for dominator optimizations. */
98 : struct opt_stats_d
99 : {
100 : long num_stmts;
101 : long num_exprs_considered;
102 : long num_re;
103 : long num_const_prop;
104 : long num_copy_prop;
105 : };
106 :
107 : static struct opt_stats_d opt_stats;
108 :
109 : /* Local functions. */
110 : static void record_equality (tree, tree, class const_and_copies *);
111 : static void record_equivalences_from_phis (basic_block);
112 : static void record_equivalences_from_incoming_edge (basic_block,
113 : class const_and_copies *,
114 : class avail_exprs_stack *,
115 : bitmap blocks_on_stack);
116 : static void eliminate_redundant_computations (gimple_stmt_iterator *,
117 : class const_and_copies *,
118 : class avail_exprs_stack *);
119 : static void record_equivalences_from_stmt (gimple *, int,
120 : class avail_exprs_stack *);
121 : static void dump_dominator_optimization_stats (FILE *file,
122 : hash_table<expr_elt_hasher> *);
123 : static void record_temporary_equivalences (edge, class const_and_copies *,
124 : class avail_exprs_stack *, bitmap);
125 :
126 : /* Constructor for EDGE_INFO. An EDGE_INFO instance is always
127 : associated with an edge E. */
128 :
129 36059603 : edge_info::edge_info (edge e)
130 : {
131 : /* Free the old one associated with E, if it exists and
132 : associate our new object with E. */
133 36059603 : free_dom_edge_info (e);
134 36059603 : e->aux = this;
135 :
136 : /* And initialize the embedded vectors. */
137 36059603 : simple_equivalences = vNULL;
138 36059603 : cond_equivalences = vNULL;
139 36059603 : }
140 :
141 : /* Destructor just needs to release the vectors. */
142 :
143 36059603 : edge_info::~edge_info (void)
144 : {
145 36059603 : this->cond_equivalences.release ();
146 36059603 : this->simple_equivalences.release ();
147 36059603 : }
148 :
149 : /* NAME is known to have the value VALUE, which must be a constant.
150 :
151 : Walk through its use-def chain to see if there are other equivalences
152 : we might be able to derive.
153 :
154 : RECURSION_LIMIT controls how far back we recurse through the use-def
155 : chains. */
156 :
157 : void
158 13105348 : edge_info::derive_equivalences (tree name, tree value, int recursion_limit)
159 : {
160 15086536 : if (TREE_CODE (name) != SSA_NAME || TREE_CODE (value) != INTEGER_CST)
161 : return;
162 :
163 : /* This records the equivalence for the toplevel object. Do
164 : this before checking the recursion limit. */
165 15086256 : simple_equivalences.safe_push (equiv_pair (name, value));
166 :
167 : /* Limit how far up the use-def chains we are willing to walk. */
168 15086256 : if (recursion_limit == 0)
169 : return;
170 :
171 : /* We can walk up the use-def chains to potentially find more
172 : equivalences. */
173 15071895 : gimple *def_stmt = SSA_NAME_DEF_STMT (name);
174 15071895 : if (is_gimple_assign (def_stmt))
175 : {
176 9667592 : enum tree_code code = gimple_assign_rhs_code (def_stmt);
177 9667592 : switch (code)
178 : {
179 : /* If the result of an OR is zero, then its operands are, too. */
180 577476 : case BIT_IOR_EXPR:
181 577476 : if (integer_zerop (value))
182 : {
183 319288 : tree rhs1 = gimple_assign_rhs1 (def_stmt);
184 319288 : tree rhs2 = gimple_assign_rhs2 (def_stmt);
185 :
186 319288 : value = build_zero_cst (TREE_TYPE (rhs1));
187 319288 : derive_equivalences (rhs1, value, recursion_limit - 1);
188 319288 : value = build_zero_cst (TREE_TYPE (rhs2));
189 319288 : derive_equivalences (rhs2, value, recursion_limit - 1);
190 : }
191 : break;
192 :
193 : /* If the result of an AND is nonzero, then its operands are, too. */
194 1013275 : case BIT_AND_EXPR:
195 1013275 : if (!integer_zerop (value))
196 : {
197 422511 : tree rhs1 = gimple_assign_rhs1 (def_stmt);
198 422511 : tree rhs2 = gimple_assign_rhs2 (def_stmt);
199 :
200 : /* If either operand has a boolean range, then we
201 : know its value must be one, otherwise we just know it
202 : is nonzero. The former is clearly useful, I haven't
203 : seen cases where the latter is helpful yet. */
204 422511 : if (TREE_CODE (rhs1) == SSA_NAME)
205 : {
206 422511 : if (ssa_name_has_boolean_range (rhs1))
207 : {
208 258538 : value = build_one_cst (TREE_TYPE (rhs1));
209 258538 : derive_equivalences (rhs1, value, recursion_limit - 1);
210 : }
211 : }
212 422511 : if (TREE_CODE (rhs2) == SSA_NAME)
213 : {
214 260483 : if (ssa_name_has_boolean_range (rhs2))
215 : {
216 258255 : value = build_one_cst (TREE_TYPE (rhs2));
217 258255 : derive_equivalences (rhs2, value, recursion_limit - 1);
218 : }
219 : }
220 : }
221 : break;
222 :
223 : /* If LHS is an SSA_NAME and RHS is a constant integer and LHS was
224 : set via a widening type conversion, then we may be able to record
225 : additional equivalences. */
226 428596 : CASE_CONVERT:
227 428596 : {
228 428596 : tree rhs = gimple_assign_rhs1 (def_stmt);
229 428596 : tree rhs_type = TREE_TYPE (rhs);
230 428596 : if (INTEGRAL_TYPE_P (rhs_type)
231 426201 : && (TYPE_PRECISION (TREE_TYPE (name))
232 426201 : >= TYPE_PRECISION (rhs_type))
233 660507 : && int_fits_type_p (value, rhs_type))
234 222171 : derive_equivalences (rhs,
235 : fold_convert (rhs_type, value),
236 : recursion_limit - 1);
237 : break;
238 : }
239 :
240 : /* We can invert the operation of these codes trivially if
241 : one of the RHS operands is a constant to produce a known
242 : value for the other RHS operand. */
243 1010972 : case POINTER_PLUS_EXPR:
244 1010972 : case PLUS_EXPR:
245 1010972 : {
246 1010972 : tree rhs1 = gimple_assign_rhs1 (def_stmt);
247 1010972 : tree rhs2 = gimple_assign_rhs2 (def_stmt);
248 :
249 : /* If either argument is a constant, then we can compute
250 : a constant value for the nonconstant argument. */
251 1010972 : if (TREE_CODE (rhs1) == INTEGER_CST
252 0 : && TREE_CODE (rhs2) == SSA_NAME)
253 0 : derive_equivalences (rhs2,
254 0 : fold_binary (MINUS_EXPR, TREE_TYPE (rhs1),
255 : value, rhs1),
256 : recursion_limit - 1);
257 1010972 : else if (TREE_CODE (rhs2) == INTEGER_CST
258 958579 : && TREE_CODE (rhs1) == SSA_NAME)
259 958579 : derive_equivalences (rhs1,
260 958579 : fold_binary (MINUS_EXPR, TREE_TYPE (rhs1),
261 : value, rhs2),
262 : recursion_limit - 1);
263 : break;
264 : }
265 :
266 : /* If one of the operands is a constant, then we can compute
267 : the value of the other operand. If both operands are
268 : SSA_NAMEs, then they must be equal if the result is zero. */
269 74430 : case MINUS_EXPR:
270 74430 : {
271 74430 : tree rhs1 = gimple_assign_rhs1 (def_stmt);
272 74430 : tree rhs2 = gimple_assign_rhs2 (def_stmt);
273 :
274 : /* If either argument is a constant, then we can compute
275 : a constant value for the nonconstant argument. */
276 74430 : if (TREE_CODE (rhs1) == INTEGER_CST
277 634 : && TREE_CODE (rhs2) == SSA_NAME)
278 634 : derive_equivalences (rhs2,
279 634 : fold_binary (MINUS_EXPR, TREE_TYPE (rhs1),
280 : rhs1, value),
281 : recursion_limit - 1);
282 73796 : else if (TREE_CODE (rhs2) == INTEGER_CST
283 29524 : && TREE_CODE (rhs1) == SSA_NAME)
284 29524 : derive_equivalences (rhs1,
285 29524 : fold_binary (PLUS_EXPR, TREE_TYPE (rhs1),
286 : value, rhs2),
287 : recursion_limit - 1);
288 44272 : else if (integer_zerop (value))
289 : {
290 16075 : tree cond = build2 (EQ_EXPR, boolean_type_node,
291 : gimple_assign_rhs1 (def_stmt),
292 : gimple_assign_rhs2 (def_stmt));
293 16075 : tree inverted = invert_truthvalue (cond);
294 16075 : record_conditions (&this->cond_equivalences, cond, inverted);
295 : }
296 : break;
297 : }
298 :
299 667482 : case EQ_EXPR:
300 667482 : case NE_EXPR:
301 667482 : {
302 266991 : if ((code == EQ_EXPR && integer_onep (value))
303 794701 : || (code == NE_EXPR && integer_zerop (value)))
304 : {
305 393517 : tree rhs1 = gimple_assign_rhs1 (def_stmt);
306 393517 : tree rhs2 = gimple_assign_rhs2 (def_stmt);
307 :
308 : /* If either argument is a constant, then record the
309 : other argument as being the same as that constant.
310 :
311 : If neither operand is a constant, then we have a
312 : conditional name == name equivalence. */
313 393517 : if (TREE_CODE (rhs1) == INTEGER_CST)
314 0 : derive_equivalences (rhs2, rhs1, recursion_limit - 1);
315 393517 : else if (TREE_CODE (rhs2) == INTEGER_CST)
316 179406 : derive_equivalences (rhs1, rhs2, recursion_limit - 1);
317 : }
318 : else
319 : {
320 273965 : tree cond = build2 (code, boolean_type_node,
321 : gimple_assign_rhs1 (def_stmt),
322 273965 : gimple_assign_rhs2 (def_stmt));
323 273965 : tree inverted = invert_truthvalue (cond);
324 273965 : if (integer_zerop (value))
325 127219 : std::swap (cond, inverted);
326 273965 : record_conditions (&this->cond_equivalences, cond, inverted);
327 : }
328 : break;
329 : }
330 :
331 : /* For BIT_NOT and NEGATE, we can just apply the operation to the
332 : VALUE to get the new equivalence. It will always be a constant
333 : so we can recurse. */
334 13331 : case BIT_NOT_EXPR:
335 13331 : case NEGATE_EXPR:
336 13331 : {
337 13331 : tree rhs = gimple_assign_rhs1 (def_stmt);
338 13331 : tree res;
339 : /* If this is a NOT and the operand has a boolean range, then we
340 : know its value must be zero or one. We are not supposed to
341 : have a BIT_NOT_EXPR for boolean types with precision > 1 in
342 : the general case, see e.g. the handling of TRUTH_NOT_EXPR in
343 : the gimplifier, but it can be generated by match.pd out of
344 : a BIT_XOR_EXPR wrapped in a BIT_AND_EXPR. Now the handling
345 : of BIT_AND_EXPR above already forces a specific semantics for
346 : boolean types with precision > 1 so we must do the same here,
347 : otherwise we could change the semantics of TRUTH_NOT_EXPR for
348 : boolean types with precision > 1. */
349 13331 : if (code == BIT_NOT_EXPR
350 13117 : && TREE_CODE (rhs) == SSA_NAME
351 26448 : && ssa_name_has_boolean_range (rhs))
352 : {
353 12678 : if ((TREE_INT_CST_LOW (value) & 1) == 0)
354 5864 : res = build_one_cst (TREE_TYPE (rhs));
355 : else
356 6814 : res = build_zero_cst (TREE_TYPE (rhs));
357 : }
358 : else
359 653 : res = fold_build1 (code, TREE_TYPE (rhs), value);
360 13331 : derive_equivalences (rhs, res, recursion_limit - 1);
361 13331 : break;
362 : }
363 :
364 5882030 : default:
365 5882030 : {
366 5882030 : if (TREE_CODE_CLASS (code) == tcc_comparison)
367 : {
368 527957 : tree cond = build2 (code, boolean_type_node,
369 : gimple_assign_rhs1 (def_stmt),
370 527957 : gimple_assign_rhs2 (def_stmt));
371 527957 : tree inverted = invert_truthvalue (cond);
372 527957 : if (integer_zerop (value))
373 227959 : std::swap (cond, inverted);
374 527957 : record_conditions (&this->cond_equivalences, cond, inverted);
375 527957 : break;
376 : }
377 : break;
378 : }
379 : }
380 : }
381 : }
382 :
383 : void
384 15752094 : edge_info::record_simple_equiv (tree lhs, tree rhs)
385 : {
386 : /* If the RHS is a constant, then we may be able to derive
387 : further equivalences. Else just record the name = name
388 : equivalence. */
389 15752094 : if (TREE_CODE (rhs) == INTEGER_CST)
390 12527522 : derive_equivalences (lhs, rhs, 4);
391 : else
392 3224572 : simple_equivalences.safe_push (equiv_pair (lhs, rhs));
393 15752094 : }
394 :
395 : /* Free the edge_info data attached to E, if it exists and
396 : clear e->aux. */
397 :
398 : void
399 130002629 : free_dom_edge_info (edge e)
400 : {
401 130002629 : class edge_info *edge_info = (class edge_info *)e->aux;
402 :
403 130002629 : if (edge_info)
404 36059603 : delete edge_info;
405 130002629 : e->aux = NULL;
406 130002629 : }
407 :
408 : /* Free all EDGE_INFO structures associated with edges in the CFG.
409 : If a particular edge can be threaded, copy the redirection
410 : target from the EDGE_INFO structure into the edge's AUX field
411 : as required by code to update the CFG and SSA graph for
412 : jump threading. */
413 :
414 : static void
415 2088904 : free_all_edge_infos (void)
416 : {
417 2088904 : basic_block bb;
418 2088904 : edge_iterator ei;
419 2088904 : edge e;
420 :
421 23420318 : FOR_EACH_BB_FN (bb, cfun)
422 : {
423 51434205 : FOR_EACH_EDGE (e, ei, bb->preds)
424 30102791 : free_dom_edge_info (e);
425 : }
426 2088904 : }
427 :
428 : /* Return TRUE if BB has precisely two preds, one of which
429 : is a backedge from a forwarder block where the forwarder
430 : block is a direct successor of BB. Being a forwarder
431 : block, it has no side effects other than transfer of
432 : control. Otherwise return FALSE. */
433 :
434 : static bool
435 18047579 : single_block_loop_p (basic_block bb)
436 : {
437 : /* Two preds. */
438 18047579 : if (EDGE_COUNT (bb->preds) != 2)
439 : return false;
440 :
441 : /* One and only one of the edges must be marked with
442 : EDGE_DFS_BACK. */
443 5254173 : basic_block pred = NULL;
444 5254173 : unsigned int count = 0;
445 5254173 : if (EDGE_PRED (bb, 0)->flags & EDGE_DFS_BACK)
446 : {
447 1871779 : pred = EDGE_PRED (bb, 0)->src;
448 1871779 : count++;
449 : }
450 5254173 : if (EDGE_PRED (bb, 1)->flags & EDGE_DFS_BACK)
451 : {
452 402368 : pred = EDGE_PRED (bb, 1)->src;
453 402368 : count++;
454 : }
455 :
456 5254173 : if (count != 1)
457 : return false;
458 :
459 : /* Now examine PRED. It should have a single predecessor which
460 : is BB and a single successor that is also BB. */
461 2274147 : if (EDGE_COUNT (pred->preds) != 1
462 19207931 : || EDGE_COUNT (pred->succs) != 1
463 2193619 : || EDGE_PRED (pred, 0)->src != bb
464 3369334 : || EDGE_SUCC (pred, 0)->dest != bb)
465 : return false;
466 :
467 : /* This looks good from a CFG standpoint. Now look at the guts
468 : of PRED. Basically we want to verify there are no PHI nodes
469 : and no real statements. */
470 1095187 : if (! gimple_seq_empty_p (phi_nodes (pred)))
471 : return false;
472 :
473 1090537 : gimple_stmt_iterator gsi;
474 2203928 : for (gsi = gsi_last_bb (pred); !gsi_end_p (gsi); gsi_prev (&gsi))
475 : {
476 68697 : gimple *stmt = gsi_stmt (gsi);
477 :
478 68697 : switch (gimple_code (stmt))
479 : {
480 0 : case GIMPLE_LABEL:
481 0 : if (DECL_NONLOCAL (gimple_label_label (as_a <glabel *> (stmt))))
482 : return false;
483 : break;
484 :
485 : case GIMPLE_DEBUG:
486 : break;
487 :
488 : default:
489 : return false;
490 : }
491 : }
492 :
493 : return true;
494 : }
495 :
496 : /* We have finished optimizing BB, record any information implied by
497 : taking a specific outgoing edge from BB. */
498 :
499 : static void
500 44681135 : record_edge_info (basic_block bb)
501 : {
502 44681135 : gimple_stmt_iterator gsi = gsi_last_bb (bb);
503 44681135 : class edge_info *edge_info;
504 :
505 : /* Free all the outgoing edge info data associated with
506 : BB's outgoing edges. */
507 44681135 : edge e;
508 44681135 : edge_iterator ei;
509 106806700 : FOR_EACH_EDGE (e, ei, bb->succs)
510 62125565 : free_dom_edge_info (e);
511 :
512 44681135 : if (! gsi_end_p (gsi))
513 : {
514 38510523 : gimple *stmt = gsi_stmt (gsi);
515 38510523 : location_t loc = gimple_location (stmt);
516 :
517 38510523 : if (gimple_code (stmt) == GIMPLE_SWITCH)
518 : {
519 66053 : gswitch *switch_stmt = as_a <gswitch *> (stmt);
520 66053 : tree index = gimple_switch_index (switch_stmt);
521 :
522 66053 : if (TREE_CODE (index) == SSA_NAME)
523 : {
524 66037 : int i;
525 66037 : int n_labels = gimple_switch_num_labels (switch_stmt);
526 : /* info contains NULL, error_mark_node or a value.
527 : error_mark signifies there are multiple values already.
528 : A NULL signifies there it is uninitialized.
529 : A value signifies that is the only value on that edge
530 : to that bb. */
531 66037 : tree *info = XCNEWVEC (tree, last_basic_block_for_fn (cfun));
532 :
533 534938 : for (i = 0; i < n_labels; i++)
534 : {
535 468901 : tree label = gimple_switch_label (switch_stmt, i);
536 468901 : basic_block target_bb
537 468901 : = label_to_block (cfun, CASE_LABEL (label));
538 : /* The default case is a case with multiple values.
539 : If the value is already set then it has multiple values. */
540 468901 : if (CASE_HIGH (label)
541 442795 : || !CASE_LOW (label)
542 845659 : || info[target_bb->index])
543 141573 : info[target_bb->index] = error_mark_node;
544 : else
545 : /* Record the one value that can be on that edge to the
546 : target_bb. */
547 327328 : info[target_bb->index] = CASE_LOW (label);
548 : }
549 :
550 478692 : FOR_EACH_EDGE (e, ei, bb->succs)
551 : {
552 412655 : basic_block target_bb = e->dest;
553 412655 : tree value = info[target_bb->index];
554 :
555 412655 : if (value != NULL && value != error_mark_node)
556 : {
557 300509 : tree x = fold_convert_loc (loc, TREE_TYPE (index),
558 : value);
559 300509 : edge_info = new class edge_info (e);
560 300509 : edge_info->record_simple_equiv (index, x);
561 : }
562 : }
563 66037 : free (info);
564 : }
565 : }
566 :
567 : /* A COND_EXPR may create equivalences too. */
568 38510523 : if (gimple_code (stmt) == GIMPLE_COND)
569 : {
570 18047579 : edge true_edge;
571 18047579 : edge false_edge;
572 :
573 18047579 : tree op0 = gimple_cond_lhs (stmt);
574 18047579 : tree op1 = gimple_cond_rhs (stmt);
575 18047579 : enum tree_code code = gimple_cond_code (stmt);
576 :
577 18047579 : extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
578 :
579 : /* Special case comparing booleans against a constant as we
580 : know the value of OP0 on both arms of the branch. i.e., we
581 : can record an equivalence for OP0 rather than COND.
582 :
583 : However, don't do this if the constant isn't zero or one.
584 : Such conditionals will get optimized more thoroughly during
585 : the domwalk. */
586 18047579 : if ((code == EQ_EXPR || code == NE_EXPR)
587 13833673 : && TREE_CODE (op0) == SSA_NAME
588 13665856 : && ssa_name_has_boolean_range (op0)
589 2053424 : && is_gimple_min_invariant (op1)
590 20038792 : && (integer_zerop (op1) || integer_onep (op1)))
591 : {
592 1991213 : tree true_val = constant_boolean_node (true, TREE_TYPE (op0));
593 1991213 : tree false_val = constant_boolean_node (false, TREE_TYPE (op0));
594 :
595 1991213 : if (code == EQ_EXPR)
596 : {
597 80085 : edge_info = new class edge_info (true_edge);
598 118514 : edge_info->record_simple_equiv (op0,
599 80085 : (integer_zerop (op1)
600 : ? false_val : true_val));
601 80085 : edge_info = new class edge_info (false_edge);
602 118514 : edge_info->record_simple_equiv (op0,
603 80085 : (integer_zerop (op1)
604 : ? true_val : false_val));
605 : }
606 : else
607 : {
608 1911128 : edge_info = new class edge_info (true_edge);
609 1914376 : edge_info->record_simple_equiv (op0,
610 1911128 : (integer_zerop (op1)
611 : ? true_val : false_val));
612 1911128 : edge_info = new class edge_info (false_edge);
613 1914376 : edge_info->record_simple_equiv (op0,
614 1911128 : (integer_zerop (op1)
615 : ? false_val : true_val));
616 : }
617 : }
618 : /* This can show up in the IL as a result of copy propagation
619 : it will eventually be canonicalized, but we have to cope
620 : with this case within the pass. */
621 16056366 : else if (is_gimple_min_invariant (op0)
622 16056366 : && TREE_CODE (op1) == SSA_NAME)
623 : {
624 0 : tree cond = build2 (code, boolean_type_node, op0, op1);
625 0 : tree inverted = invert_truthvalue_loc (loc, cond);
626 0 : bool can_infer_simple_equiv
627 0 : = !(HONOR_SIGNED_ZEROS (op0) && real_maybe_zerop (op0))
628 0 : && !DECIMAL_FLOAT_MODE_P (element_mode (TREE_TYPE (op0)));
629 0 : class edge_info *edge_info;
630 :
631 0 : edge_info = new class edge_info (true_edge);
632 0 : record_conditions (&edge_info->cond_equivalences, cond, inverted);
633 :
634 0 : if (can_infer_simple_equiv && code == EQ_EXPR)
635 0 : edge_info->record_simple_equiv (op1, op0);
636 :
637 0 : edge_info = new class edge_info (false_edge);
638 0 : record_conditions (&edge_info->cond_equivalences, inverted, cond);
639 :
640 0 : if (can_infer_simple_equiv && TREE_CODE (inverted) == EQ_EXPR)
641 0 : edge_info->record_simple_equiv (op1, op0);
642 : }
643 :
644 16056366 : else if (TREE_CODE (op0) == SSA_NAME
645 16056366 : && (TREE_CODE (op1) == SSA_NAME
646 11791919 : || is_gimple_min_invariant (op1)))
647 : {
648 15888016 : tree cond = build2 (code, boolean_type_node, op0, op1);
649 15888016 : tree inverted = invert_truthvalue_loc (loc, cond);
650 15888016 : bool can_infer_simple_equiv
651 16581031 : = !(HONOR_SIGNED_ZEROS (op1) && real_maybe_zerop (op1))
652 16284694 : && !DECIMAL_FLOAT_MODE_P (element_mode (TREE_TYPE (op1)));
653 15888016 : class edge_info *edge_info;
654 :
655 15888016 : edge_info = new class edge_info (true_edge);
656 15888016 : record_conditions (&edge_info->cond_equivalences, cond, inverted);
657 :
658 15888016 : if (can_infer_simple_equiv && code == EQ_EXPR)
659 5367844 : edge_info->record_simple_equiv (op0, op1);
660 :
661 15888016 : edge_info = new class edge_info (false_edge);
662 15888016 : record_conditions (&edge_info->cond_equivalences, inverted, cond);
663 :
664 15888016 : if (can_infer_simple_equiv && TREE_CODE (inverted) == EQ_EXPR)
665 6099992 : edge_info->record_simple_equiv (op0, op1);
666 : }
667 :
668 : /* If this block is a single block loop, then we may be able to
669 : record some equivalences on the loop's exit edge. */
670 18047579 : if (single_block_loop_p (bb))
671 : {
672 : /* We know it's a single block loop. Now look at the loop
673 : exit condition. What we're looking for is whether or not
674 : the exit condition is loop invariant which we can detect
675 : by checking if all the SSA_NAMEs referenced are defined
676 : outside the loop. */
677 1033267 : if ((TREE_CODE (op0) != SSA_NAME
678 1032588 : || gimple_bb (SSA_NAME_DEF_STMT (op0)) != bb)
679 1199305 : && (TREE_CODE (op1) != SSA_NAME
680 164359 : || gimple_bb (SSA_NAME_DEF_STMT (op1)) != bb))
681 : {
682 : /* At this point we know the exit condition is loop
683 : invariant. The only way to get out of the loop is
684 : if it never traverses the backedge to begin with. This
685 : implies that any PHI nodes create equivalances that we
686 : can attach to the loop exit edge. */
687 2483 : bool alternative
688 2483 : = (EDGE_PRED (bb, 0)->flags & EDGE_DFS_BACK) ? 1 : 0;
689 :
690 2483 : gphi_iterator gsi;
691 2483 : for (gsi = gsi_start_phis (bb);
692 4165 : !gsi_end_p (gsi);
693 1682 : gsi_next (&gsi))
694 : {
695 : /* Now get the EDGE_INFO class so we can append
696 : it to our list. We want the successor edge
697 : where the destination is not the source of
698 : an incoming edge. */
699 1682 : gphi *phi = gsi.phi ();
700 1682 : tree src = PHI_ARG_DEF (phi, alternative);
701 1682 : tree dst = PHI_RESULT (phi);
702 :
703 : /* If the other alternative is the same as the result,
704 : then this is a degenerate and can be ignored. */
705 1682 : if (dst == PHI_ARG_DEF (phi, !alternative))
706 359 : continue;
707 :
708 1323 : if (EDGE_SUCC (bb, 0)->dest
709 1323 : != EDGE_PRED (bb, !alternative)->src)
710 369 : edge_info = (class edge_info *)EDGE_SUCC (bb, 0)->aux;
711 : else
712 954 : edge_info = (class edge_info *)EDGE_SUCC (bb, 1)->aux;
713 :
714 : /* Note that since this processing is done independently
715 : of other edge equivalency processing, we may not
716 : have an EDGE_INFO structure set up yet. */
717 1323 : if (edge_info == NULL)
718 636 : edge_info = new class edge_info (false_edge);
719 1323 : edge_info->record_simple_equiv (dst, src);
720 : }
721 : }
722 : }
723 : }
724 : }
725 44681135 : }
726 :
727 : class dom_jt_state : public jt_state
728 : {
729 : public:
730 2088904 : dom_jt_state (const_and_copies *copies, avail_exprs_stack *avails)
731 2088904 : : m_copies (copies), m_avails (avails)
732 : {
733 2088904 : bitmap_tree_view (m_blocks_on_stack);
734 2088904 : }
735 16580831 : void push (edge e) override
736 : {
737 16580831 : m_copies->push_marker ();
738 16580831 : m_avails->push_marker ();
739 16580831 : jt_state::push (e);
740 16580831 : }
741 16580831 : void pop () override
742 : {
743 16580831 : m_copies->pop_to_marker ();
744 16580831 : m_avails->pop_to_marker ();
745 16580831 : jt_state::pop ();
746 16580831 : }
747 15342707 : void register_equivs_edge (edge e) override
748 : {
749 15342707 : record_temporary_equivalences (e, m_copies, m_avails, m_blocks_on_stack);
750 15342707 : }
751 : void register_equiv (tree dest, tree src, bool update) override;
752 70049163 : bitmap get_blocks_on_stack () { return m_blocks_on_stack; }
753 : private:
754 : const_and_copies *m_copies;
755 : avail_exprs_stack *m_avails;
756 : /* Set of blocks on the stack, to be used for medium-fast
757 : dominance queries in back_propagate_equivalences. */
758 : auto_bitmap m_blocks_on_stack;
759 : };
760 :
761 : void
762 20752217 : dom_jt_state::register_equiv (tree dest, tree src, bool)
763 : {
764 20752217 : m_copies->record_const_or_copy (dest, src);
765 20752217 : }
766 :
767 2088904 : class dom_jt_simplifier : public hybrid_jt_simplifier
768 : {
769 : public:
770 2088904 : dom_jt_simplifier (avail_exprs_stack *avails, gimple_ranger *ranger,
771 : path_range_query *query)
772 4177808 : : hybrid_jt_simplifier (ranger, query), m_avails (avails) { }
773 :
774 : private:
775 : tree simplify (gimple *, gimple *, basic_block, jt_state *) override;
776 : avail_exprs_stack *m_avails;
777 : };
778 :
779 : tree
780 30744032 : dom_jt_simplifier::simplify (gimple *stmt, gimple *within_stmt,
781 : basic_block bb, jt_state *state)
782 : {
783 : /* First see if the conditional is in the hash table. */
784 30744032 : tree cached_lhs = m_avails->lookup_avail_expr (stmt, false, true);
785 30744032 : if (cached_lhs)
786 : return cached_lhs;
787 :
788 : /* Otherwise call the ranger if possible. */
789 29946112 : if (state)
790 8482171 : return hybrid_jt_simplifier::simplify (stmt, within_stmt, bb, state);
791 :
792 : return NULL;
793 : }
794 :
795 4177808 : class dom_opt_dom_walker : public dom_walker
796 : {
797 : public:
798 2088904 : dom_opt_dom_walker (cdi_direction direction,
799 : jump_threader *threader,
800 : dom_jt_state *state,
801 : gimple_ranger *ranger,
802 : const_and_copies *const_and_copies,
803 : avail_exprs_stack *avail_exprs_stack)
804 2088904 : : dom_walker (direction, REACHABLE_BLOCKS)
805 : {
806 2088904 : m_ranger = ranger;
807 2088904 : m_state = state;
808 2088904 : m_dummy_cond = gimple_build_cond (NE_EXPR, integer_zero_node,
809 : integer_zero_node, NULL, NULL);
810 2088904 : m_const_and_copies = const_and_copies;
811 2088904 : m_avail_exprs_stack = avail_exprs_stack;
812 2088904 : m_threader = threader;
813 2088904 : }
814 :
815 : edge before_dom_children (basic_block) final override;
816 : void after_dom_children (basic_block) final override;
817 :
818 : private:
819 :
820 : /* Unwindable equivalences, both const/copy and expression varieties. */
821 : class const_and_copies *m_const_and_copies;
822 : class avail_exprs_stack *m_avail_exprs_stack;
823 :
824 : /* Dummy condition to avoid creating lots of throw away statements. */
825 : gcond *m_dummy_cond;
826 :
827 : /* Optimize a single statement within a basic block using the
828 : various tables mantained by DOM. Returns the taken edge if
829 : the statement is a conditional with a statically determined
830 : value. */
831 : edge optimize_stmt (basic_block, gimple_stmt_iterator *, bool *);
832 :
833 : void set_global_ranges_from_unreachable_edges (basic_block);
834 :
835 : void test_for_singularity (gimple *, avail_exprs_stack *);
836 : edge fold_cond (gcond *cond);
837 :
838 : jump_threader *m_threader;
839 : gimple_ranger *m_ranger;
840 : dom_jt_state *m_state;
841 : };
842 :
843 : /* Jump threading, redundancy elimination and const/copy propagation.
844 :
845 : This pass may expose new symbols that need to be renamed into SSA. For
846 : every new symbol exposed, its corresponding bit will be set in
847 : VARS_TO_RENAME. */
848 :
849 : namespace {
850 :
851 : const pass_data pass_data_dominator =
852 : {
853 : GIMPLE_PASS, /* type */
854 : "dom", /* name */
855 : OPTGROUP_NONE, /* optinfo_flags */
856 : TV_TREE_SSA_DOMINATOR_OPTS, /* tv_id */
857 : ( PROP_cfg | PROP_ssa ), /* properties_required */
858 : 0, /* properties_provided */
859 : 0, /* properties_destroyed */
860 : 0, /* todo_flags_start */
861 : ( TODO_cleanup_cfg | TODO_update_ssa ), /* todo_flags_finish */
862 : };
863 :
864 : class pass_dominator : public gimple_opt_pass
865 : {
866 : public:
867 866301 : pass_dominator (gcc::context *ctxt)
868 866301 : : gimple_opt_pass (pass_data_dominator, ctxt),
869 1732602 : may_peel_loop_headers_p (false)
870 : {}
871 :
872 : /* opt_pass methods: */
873 577534 : opt_pass * clone () final override { return new pass_dominator (m_ctxt); }
874 866301 : void set_pass_param (unsigned int n, bool param) final override
875 : {
876 866301 : gcc_assert (n == 0);
877 866301 : may_peel_loop_headers_p = param;
878 866301 : }
879 2089691 : bool gate (function *) final override { return flag_tree_dom != 0; }
880 : unsigned int execute (function *) final override;
881 :
882 : private:
883 : /* This flag is used to prevent loops from being peeled repeatedly in jump
884 : threading; it will be removed once we preserve loop structures throughout
885 : the compilation -- we will be able to mark the affected loops directly in
886 : jump threading, and avoid peeling them next time. */
887 : bool may_peel_loop_headers_p;
888 : }; // class pass_dominator
889 :
890 : unsigned int
891 2088904 : pass_dominator::execute (function *fun)
892 : {
893 2088904 : memset (&opt_stats, 0, sizeof (opt_stats));
894 :
895 : /* Create our hash tables. */
896 2088904 : hash_table<expr_elt_hasher> *avail_exprs
897 2088904 : = new hash_table<expr_elt_hasher> (1024);
898 2088904 : class avail_exprs_stack *avail_exprs_stack
899 2088904 : = new class avail_exprs_stack (avail_exprs);
900 2088904 : class const_and_copies *const_and_copies = new class const_and_copies ();
901 2088904 : need_eh_cleanup = BITMAP_ALLOC (NULL);
902 2088904 : need_noreturn_fixup.create (0);
903 :
904 2088904 : calculate_dominance_info (CDI_DOMINATORS);
905 2088904 : cfg_altered = false;
906 :
907 : /* We need to know loop structures in order to avoid destroying them
908 : in jump threading. Note that we still can e.g. thread through loop
909 : headers to an exit edge, or through loop header to the loop body, assuming
910 : that we update the loop info.
911 :
912 : TODO: We don't need to set LOOPS_HAVE_PREHEADERS generally, but due
913 : to several overly conservative bail-outs in jump threading, case
914 : gcc.dg/tree-ssa/pr21417.c can't be threaded if loop preheader is
915 : missing. We should improve jump threading in future then
916 : LOOPS_HAVE_PREHEADERS won't be needed here. */
917 2088904 : loop_optimizer_init (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES
918 : | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS);
919 :
920 : /* We need accurate information regarding back edges in the CFG
921 : for jump threading; this may include back edges that are not part of
922 : a single loop. */
923 2088904 : mark_dfs_back_edges ();
924 :
925 : /* We want to create the edge info structures before the dominator walk
926 : so that they'll be in place for the jump threader, particularly when
927 : threading through a join block.
928 :
929 : The conditions will be lazily updated with global equivalences as
930 : we reach them during the dominator walk. */
931 2088904 : basic_block bb;
932 23420318 : FOR_EACH_BB_FN (bb, fun)
933 21331414 : record_edge_info (bb);
934 :
935 : /* Recursively walk the dominator tree optimizing statements. */
936 2088904 : gimple_ranger *ranger = enable_ranger (fun);
937 2088904 : path_range_query path_query (*ranger);
938 2088904 : dom_jt_simplifier simplifier (avail_exprs_stack, ranger, &path_query);
939 2088904 : dom_jt_state state (const_and_copies, avail_exprs_stack);
940 2088904 : jump_threader threader (&simplifier, &state);
941 2088904 : dom_opt_dom_walker walker (CDI_DOMINATORS,
942 : &threader,
943 : &state,
944 : ranger,
945 : const_and_copies,
946 2088904 : avail_exprs_stack);
947 2088904 : walker.walk (fun->cfg->x_entry_block_ptr);
948 :
949 2088904 : ranger->export_global_ranges ();
950 2088904 : disable_ranger (fun);
951 :
952 : /* Look for blocks where we cleared EDGE_EXECUTABLE on an outgoing
953 : edge. When found, remove jump threads which contain any outgoing
954 : edge from the affected block. */
955 2088904 : if (cfg_altered)
956 : {
957 4362536 : FOR_EACH_BB_FN (bb, fun)
958 : {
959 4305220 : edge_iterator ei;
960 4305220 : edge e;
961 :
962 : /* First see if there are any edges without EDGE_EXECUTABLE
963 : set. */
964 4305220 : bool found = false;
965 10319556 : FOR_EACH_EDGE (e, ei, bb->succs)
966 : {
967 6220663 : if ((e->flags & EDGE_EXECUTABLE) == 0)
968 : {
969 : found = true;
970 : break;
971 : }
972 : }
973 :
974 : /* If there were any such edges found, then remove jump threads
975 : containing any edge leaving BB. */
976 4305220 : if (found)
977 602237 : FOR_EACH_EDGE (e, ei, bb->succs)
978 395910 : threader.remove_jump_threads_including (e);
979 : }
980 : }
981 :
982 2088904 : {
983 2088904 : gimple_stmt_iterator gsi;
984 2088904 : basic_block bb;
985 23420318 : FOR_EACH_BB_FN (bb, fun)
986 : {
987 214806923 : for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
988 172144095 : update_stmt_if_modified (gsi_stmt (gsi));
989 : }
990 : }
991 :
992 : /* If we exposed any new variables, go ahead and put them into
993 : SSA form now, before we handle jump threading. This simplifies
994 : interactions between rewriting of _DECL nodes into SSA form
995 : and rewriting SSA_NAME nodes into SSA form after block
996 : duplication and CFG manipulation. */
997 2088904 : update_ssa (TODO_update_ssa);
998 :
999 2088904 : free_all_edge_infos ();
1000 :
1001 : /* Thread jumps, creating duplicate blocks as needed. */
1002 2088904 : cfg_altered |= threader.thread_through_all_blocks (may_peel_loop_headers_p);
1003 :
1004 2088904 : if (cfg_altered)
1005 133205 : free_dominance_info (CDI_DOMINATORS);
1006 :
1007 : /* Removal of statements may make some EH edges dead. Purge
1008 : such edges from the CFG as needed. */
1009 2088904 : if (!bitmap_empty_p (need_eh_cleanup))
1010 : {
1011 624 : unsigned i;
1012 624 : bitmap_iterator bi;
1013 :
1014 : /* Jump threading may have created forwarder blocks from blocks
1015 : needing EH cleanup; the new successor of these blocks, which
1016 : has inherited from the original block, needs the cleanup.
1017 : Don't clear bits in the bitmap, as that can break the bitmap
1018 : iterator. */
1019 1996 : EXECUTE_IF_SET_IN_BITMAP (need_eh_cleanup, 0, i, bi)
1020 : {
1021 1372 : basic_block bb = BASIC_BLOCK_FOR_FN (fun, i);
1022 1372 : if (bb == NULL)
1023 0 : continue;
1024 2815 : while (single_succ_p (bb)
1025 1486 : && (single_succ_edge (bb)->flags
1026 123 : & (EDGE_EH|EDGE_DFS_BACK)) == 0)
1027 114 : bb = single_succ (bb);
1028 1372 : if (bb == EXIT_BLOCK_PTR_FOR_FN (fun))
1029 43 : continue;
1030 1329 : if ((unsigned) bb->index != i)
1031 55 : bitmap_set_bit (need_eh_cleanup, bb->index);
1032 : }
1033 :
1034 624 : gimple_purge_all_dead_eh_edges (need_eh_cleanup);
1035 624 : bitmap_clear (need_eh_cleanup);
1036 : }
1037 :
1038 : /* Fixup stmts that became noreturn calls. This may require splitting
1039 : blocks and thus isn't possible during the dominator walk or before
1040 : jump threading finished. Do this in reverse order so we don't
1041 : inadvertedly remove a stmt we want to fixup by visiting a dominating
1042 : now noreturn call first. */
1043 2088907 : while (!need_noreturn_fixup.is_empty ())
1044 : {
1045 3 : gimple *stmt = need_noreturn_fixup.pop ();
1046 3 : if (dump_file && dump_flags & TDF_DETAILS)
1047 : {
1048 0 : fprintf (dump_file, "Fixing up noreturn call ");
1049 0 : print_gimple_stmt (dump_file, stmt, 0);
1050 0 : fprintf (dump_file, "\n");
1051 : }
1052 3 : fixup_noreturn_call (stmt);
1053 : }
1054 :
1055 2088904 : statistics_counter_event (fun, "Redundant expressions eliminated",
1056 2088904 : opt_stats.num_re);
1057 2088904 : statistics_counter_event (fun, "Constants propagated",
1058 2088904 : opt_stats.num_const_prop);
1059 2088904 : statistics_counter_event (fun, "Copies propagated",
1060 2088904 : opt_stats.num_copy_prop);
1061 :
1062 : /* Debugging dumps. */
1063 2088904 : if (dump_file && (dump_flags & TDF_STATS))
1064 35 : dump_dominator_optimization_stats (dump_file, avail_exprs);
1065 :
1066 2088904 : loop_optimizer_finalize ();
1067 :
1068 : /* Delete our main hashtable. */
1069 2088904 : delete avail_exprs;
1070 2088904 : avail_exprs = NULL;
1071 :
1072 : /* Free asserted bitmaps and stacks. */
1073 2088904 : BITMAP_FREE (need_eh_cleanup);
1074 2088904 : need_noreturn_fixup.release ();
1075 2088904 : delete avail_exprs_stack;
1076 2088904 : delete const_and_copies;
1077 :
1078 2088904 : return 0;
1079 2088904 : }
1080 :
1081 : } // anon namespace
1082 :
1083 : gimple_opt_pass *
1084 288767 : make_pass_dominator (gcc::context *ctxt)
1085 : {
1086 288767 : return new pass_dominator (ctxt);
1087 : }
1088 :
1089 : /* Valueize hook for gimple_fold_stmt_to_constant_1. */
1090 :
1091 : static tree
1092 33776853 : dom_valueize (tree t)
1093 : {
1094 33776853 : if (TREE_CODE (t) == SSA_NAME)
1095 : {
1096 24206075 : tree tem = SSA_NAME_VALUE (t);
1097 19111264 : if (tem)
1098 2985473 : return tem;
1099 : }
1100 : return t;
1101 : }
1102 :
1103 : /* We have just found an equivalence for LHS on an edge E.
1104 : Look backwards to other uses of LHS and see if we can derive
1105 : additional equivalences that are valid on edge E. */
1106 : static void
1107 11893157 : back_propagate_equivalences (tree lhs, edge e,
1108 : class const_and_copies *const_and_copies,
1109 : bitmap domby)
1110 : {
1111 11893157 : use_operand_p use_p;
1112 11893157 : imm_use_iterator iter;
1113 11893157 : basic_block dest = e->dest;
1114 11893157 : bool domok = (dom_info_state (CDI_DOMINATORS) == DOM_OK);
1115 :
1116 : /* Iterate over the uses of LHS to see if any dominate E->dest.
1117 : If so, they may create useful equivalences too.
1118 :
1119 : ??? If the code gets re-organized to a worklist to catch more
1120 : indirect opportunities and it is made to handle PHIs then this
1121 : should only consider use_stmts in basic-blocks we have already visited. */
1122 63197495 : FOR_EACH_IMM_USE_FAST (use_p, iter, lhs)
1123 : {
1124 39411181 : gimple *use_stmt = USE_STMT (use_p);
1125 :
1126 : /* Often the use is in DEST, which we trivially know we can't use.
1127 : This is cheaper than the dominator set tests below. */
1128 39411181 : if (dest == gimple_bb (use_stmt))
1129 477872 : continue;
1130 :
1131 : /* Filter out statements that can never produce a useful
1132 : equivalence. */
1133 38933309 : tree lhs2 = gimple_get_lhs (use_stmt);
1134 38933309 : if (!lhs2 || TREE_CODE (lhs2) != SSA_NAME)
1135 28842916 : continue;
1136 :
1137 10090393 : if (domok)
1138 : {
1139 5807157 : if (!dominated_by_p (CDI_DOMINATORS, dest, gimple_bb (use_stmt)))
1140 2934425 : continue;
1141 : }
1142 : else
1143 : {
1144 : /* We can use the set of BBs on the stack from a domwalk
1145 : for a medium fast way to query dominance. Profiling
1146 : has shown non-fast query dominance tests here can be fairly
1147 : expensive. */
1148 : /* This tests if USE_STMT does not dominate DEST. */
1149 4283236 : if (!bitmap_bit_p (domby, gimple_bb (use_stmt)->index))
1150 3228114 : continue;
1151 : }
1152 :
1153 : /* At this point USE_STMT dominates DEST and may result in a
1154 : useful equivalence. Try to simplify its RHS to a constant
1155 : or SSA_NAME. */
1156 3927854 : tree res = gimple_fold_stmt_to_constant_1 (use_stmt, dom_valueize,
1157 : no_follow_ssa_edges);
1158 3927854 : if (res && (TREE_CODE (res) == SSA_NAME || is_gimple_min_invariant (res)))
1159 2301748 : record_equality (lhs2, res, const_and_copies);
1160 11893157 : }
1161 11893157 : }
1162 :
1163 : /* Record into CONST_AND_COPIES and AVAIL_EXPRS_STACK any equivalences implied
1164 : by traversing edge E (which are cached in E->aux).
1165 :
1166 : Callers are responsible for managing the unwinding markers. */
1167 : static void
1168 32689753 : record_temporary_equivalences (edge e,
1169 : class const_and_copies *const_and_copies,
1170 : class avail_exprs_stack *avail_exprs_stack,
1171 : bitmap blocks_on_stack)
1172 : {
1173 32689753 : int i;
1174 32689753 : class edge_info *edge_info = (class edge_info *) e->aux;
1175 :
1176 : /* If we have info associated with this edge, record it into
1177 : our equivalence tables. */
1178 32689753 : if (edge_info)
1179 : {
1180 : cond_equivalence *eq;
1181 : /* If we have 0 = COND or 1 = COND equivalences, record them
1182 : into our expression hash tables. */
1183 90577292 : for (i = 0; edge_info->cond_equivalences.iterate (i, &eq); ++i)
1184 66991000 : avail_exprs_stack->record_cond (eq);
1185 :
1186 : edge_info::equiv_pair *seq;
1187 35479449 : for (i = 0; edge_info->simple_equivalences.iterate (i, &seq); ++i)
1188 : {
1189 11893157 : tree lhs = seq->first;
1190 11893157 : if (!lhs || TREE_CODE (lhs) != SSA_NAME)
1191 0 : continue;
1192 :
1193 : /* Record the simple NAME = VALUE equivalence. */
1194 11893157 : tree rhs = seq->second;
1195 :
1196 : /* If this is a SSA_NAME = SSA_NAME equivalence and one operand is
1197 : cheaper to compute than the other, then set up the equivalence
1198 : such that we replace the expensive one with the cheap one.
1199 :
1200 : If they are the same cost to compute, then do not record
1201 : anything. */
1202 11893157 : if (TREE_CODE (lhs) == SSA_NAME && TREE_CODE (rhs) == SSA_NAME)
1203 : {
1204 1702203 : gimple *rhs_def = SSA_NAME_DEF_STMT (rhs);
1205 1702203 : int rhs_cost = estimate_num_insns (rhs_def, &eni_size_weights);
1206 :
1207 1702203 : gimple *lhs_def = SSA_NAME_DEF_STMT (lhs);
1208 1702203 : int lhs_cost = estimate_num_insns (lhs_def, &eni_size_weights);
1209 :
1210 1702203 : if (rhs_cost > lhs_cost)
1211 180624 : record_equality (rhs, lhs, const_and_copies);
1212 1521579 : else if (rhs_cost < lhs_cost)
1213 446026 : record_equality (lhs, rhs, const_and_copies);
1214 : }
1215 : else
1216 10190954 : record_equality (lhs, rhs, const_and_copies);
1217 :
1218 :
1219 : /* Any equivalence found for LHS may result in additional
1220 : equivalences for other uses of LHS that we have already
1221 : processed. */
1222 11893157 : back_propagate_equivalences (lhs, e, const_and_copies,
1223 : blocks_on_stack);
1224 : }
1225 : }
1226 32689753 : }
1227 :
1228 : /* PHI nodes can create equivalences too.
1229 :
1230 : Ignoring any alternatives which are the same as the result, if
1231 : all the alternatives are equal, then the PHI node creates an
1232 : equivalence. */
1233 :
1234 : static void
1235 23349721 : record_equivalences_from_phis (basic_block bb)
1236 : {
1237 23349721 : gphi_iterator gsi;
1238 :
1239 32409352 : for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
1240 : {
1241 9059631 : gphi *phi = gsi.phi ();
1242 :
1243 : /* We might eliminate the PHI, so advance GSI now. */
1244 9059631 : gsi_next (&gsi);
1245 :
1246 9059631 : tree lhs = gimple_phi_result (phi);
1247 9059631 : tree rhs = NULL;
1248 9059631 : size_t i;
1249 :
1250 16296868 : for (i = 0; i < gimple_phi_num_args (phi); i++)
1251 : {
1252 15385230 : tree t = gimple_phi_arg_def (phi, i);
1253 :
1254 : /* Ignore alternatives which are the same as our LHS. Since
1255 : LHS is a PHI_RESULT, it is known to be a SSA_NAME, so we
1256 : can simply compare pointers. */
1257 15385230 : if (lhs == t)
1258 26331 : continue;
1259 :
1260 : /* If the associated edge is not marked as executable, then it
1261 : can be ignored. */
1262 15358899 : if ((gimple_phi_arg_edge (phi, i)->flags & EDGE_EXECUTABLE) == 0)
1263 113264 : continue;
1264 :
1265 15245635 : t = dom_valueize (t);
1266 :
1267 : /* If T is an SSA_NAME and its associated edge is a backedge,
1268 : then quit as we cannot utilize this equivalence. */
1269 15245635 : if (TREE_CODE (t) == SSA_NAME
1270 15245635 : && (gimple_phi_arg_edge (phi, i)->flags & EDGE_DFS_BACK))
1271 : break;
1272 :
1273 : /* If we have not processed an alternative yet, then set
1274 : RHS to this alternative. */
1275 12258316 : if (rhs == NULL)
1276 : rhs = t;
1277 : /* If we have processed an alternative (stored in RHS), then
1278 : see if it is equal to this one. If it isn't, then stop
1279 : the search. */
1280 5669891 : else if (! operand_equal_for_phi_arg_p (rhs, t))
1281 : break;
1282 : }
1283 :
1284 : /* If we had no interesting alternatives, then all the RHS alternatives
1285 : must have been the same as LHS. */
1286 9059631 : if (!rhs)
1287 2471206 : rhs = lhs;
1288 :
1289 : /* If we managed to iterate through each PHI alternative without
1290 : breaking out of the loop, then we have a PHI which may create
1291 : a useful equivalence. We do not need to record unwind data for
1292 : this, since this is a true assignment and not an equivalence
1293 : inferred from a comparison. All uses of this ssa name are dominated
1294 : by this assignment, so unwinding just costs time and space. */
1295 9059631 : if (i == gimple_phi_num_args (phi))
1296 : {
1297 911638 : if (may_propagate_copy (lhs, rhs))
1298 473620 : set_ssa_name_value (lhs, rhs);
1299 876036 : else if (virtual_operand_p (lhs))
1300 : {
1301 437708 : gimple *use_stmt;
1302 437708 : imm_use_iterator iter;
1303 437708 : use_operand_p use_p;
1304 : /* For virtual operands we have to propagate into all uses as
1305 : otherwise we will create overlapping life-ranges. */
1306 1721899 : FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
1307 2586439 : FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
1308 869978 : SET_USE (use_p, rhs);
1309 437708 : if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
1310 72 : SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs) = 1;
1311 437708 : gimple_stmt_iterator tmp_gsi = gsi_for_stmt (phi);
1312 437708 : remove_phi_node (&tmp_gsi, true);
1313 : }
1314 : }
1315 : }
1316 23349721 : }
1317 :
1318 : /* Return true if all uses of NAME are dominated by STMT or feed STMT
1319 : via a chain of single immediate uses. */
1320 :
1321 : static bool
1322 405651 : all_uses_feed_or_dominated_by_stmt (tree name, gimple *stmt)
1323 : {
1324 405651 : use_operand_p use_p, use2_p;
1325 405651 : imm_use_iterator iter;
1326 405651 : basic_block stmt_bb = gimple_bb (stmt);
1327 :
1328 2031260 : FOR_EACH_IMM_USE_FAST (use_p, iter, name)
1329 : {
1330 1443110 : gimple *use_stmt = USE_STMT (use_p), *use_stmt2;
1331 2654605 : if (use_stmt == stmt
1332 1310119 : || is_gimple_debug (use_stmt)
1333 2164340 : || (gimple_bb (use_stmt) != stmt_bb
1334 557751 : && dominated_by_p (CDI_DOMINATORS,
1335 557751 : gimple_bb (use_stmt), stmt_bb)))
1336 1211495 : continue;
1337 : while (use_stmt != stmt
1338 444106 : && is_gimple_assign (use_stmt)
1339 391040 : && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME
1340 831800 : && single_imm_use (gimple_assign_lhs (use_stmt),
1341 : &use2_p, &use_stmt2))
1342 220954 : use_stmt = use_stmt2;
1343 231615 : if (use_stmt != stmt)
1344 223152 : return false;
1345 223152 : }
1346 182499 : return true;
1347 : }
1348 :
1349 : /* Handle
1350 : _4 = x_3 & 31;
1351 : if (_4 != 0)
1352 : goto <bb 6>;
1353 : else
1354 : goto <bb 7>;
1355 : <bb 6>:
1356 : __builtin_unreachable ();
1357 : <bb 7>:
1358 :
1359 : If x_3 has no other immediate uses (checked by caller), var is the
1360 : x_3 var, we can clear low 5 bits from the non-zero bitmask. */
1361 :
1362 : static void
1363 162851 : maybe_set_nonzero_bits (edge e, tree var)
1364 : {
1365 162851 : basic_block cond_bb = e->src;
1366 325702 : gcond *cond = safe_dyn_cast <gcond *> (*gsi_last_bb (cond_bb));
1367 162851 : tree cst;
1368 :
1369 162851 : if (cond == NULL
1370 162851 : || gimple_cond_code (cond) != ((e->flags & EDGE_TRUE_VALUE)
1371 162851 : ? EQ_EXPR : NE_EXPR)
1372 49553 : || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME
1373 1745 : || !integer_zerop (gimple_cond_rhs (cond)))
1374 161310 : return;
1375 :
1376 1541 : gimple *stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond));
1377 1541 : if (!is_gimple_assign (stmt)
1378 1519 : || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR
1379 1558 : || TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST)
1380 : return;
1381 1 : if (gimple_assign_rhs1 (stmt) != var)
1382 : {
1383 1 : gimple *stmt2;
1384 :
1385 1 : if (TREE_CODE (gimple_assign_rhs1 (stmt)) != SSA_NAME)
1386 : return;
1387 1 : stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt));
1388 1 : if (!gimple_assign_cast_p (stmt2)
1389 0 : || gimple_assign_rhs1 (stmt2) != var
1390 0 : || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt2))
1391 1 : || (TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt)))
1392 0 : != TYPE_PRECISION (TREE_TYPE (var))))
1393 : return;
1394 : }
1395 0 : cst = gimple_assign_rhs2 (stmt);
1396 0 : if (POINTER_TYPE_P (TREE_TYPE (var)))
1397 : {
1398 0 : struct ptr_info_def *pi = SSA_NAME_PTR_INFO (var);
1399 0 : if (pi && pi->misalign)
1400 0 : return;
1401 0 : wide_int w = wi::bit_not (wi::to_wide (cst));
1402 0 : unsigned int bits = wi::ctz (w);
1403 0 : if (bits == 0 || bits >= HOST_BITS_PER_INT)
1404 0 : return;
1405 0 : unsigned int align = 1U << bits;
1406 0 : if (pi == NULL || pi->align < align)
1407 0 : set_ptr_info_alignment (get_ptr_info (var), align, 0);
1408 0 : }
1409 : else
1410 0 : set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var),
1411 0 : wi::to_wide (cst)));
1412 : }
1413 :
1414 : /* Set global ranges that can be determined from the C->M edge:
1415 :
1416 : <bb C>:
1417 : ...
1418 : if (something)
1419 : goto <bb N>;
1420 : else
1421 : goto <bb M>;
1422 : <bb N>:
1423 : __builtin_unreachable ();
1424 : <bb M>:
1425 : */
1426 :
1427 : void
1428 23349721 : dom_opt_dom_walker::set_global_ranges_from_unreachable_edges (basic_block bb)
1429 : {
1430 23349721 : edge pred_e = single_pred_edge_ignoring_loop_edges (bb, false);
1431 23349721 : if (!pred_e)
1432 : return;
1433 :
1434 17341503 : gimple *stmt = *gsi_last_bb (pred_e->src);
1435 17341503 : if (!stmt
1436 14554088 : || gimple_code (stmt) != GIMPLE_COND
1437 29396224 : || !assert_unreachable_fallthru_edge_p (pred_e))
1438 17122845 : return;
1439 :
1440 218658 : tree name;
1441 624309 : FOR_EACH_GORI_EXPORT_NAME (m_ranger->gori_ssa (), pred_e->src, name)
1442 405651 : if (all_uses_feed_or_dominated_by_stmt (name, stmt)
1443 : // The condition must post-dominate the definition point.
1444 588150 : && (SSA_NAME_IS_DEFAULT_DEF (name)
1445 182053 : || (gimple_bb (SSA_NAME_DEF_STMT (name))
1446 182053 : == pred_e->src)))
1447 : {
1448 177259 : value_range r (TREE_TYPE (name));
1449 :
1450 177259 : if (m_ranger->range_on_edge (r, pred_e, name)
1451 177259 : && !r.varying_p ()
1452 340183 : && !r.undefined_p ())
1453 : {
1454 162851 : set_range_info (name, r);
1455 162851 : maybe_set_nonzero_bits (pred_e, name);
1456 : }
1457 177259 : }
1458 : }
1459 :
1460 : /* Record any equivalences created by the incoming edge to BB into
1461 : CONST_AND_COPIES and AVAIL_EXPRS_STACK. If BB has more than one
1462 : incoming edge, then no equivalence is created. */
1463 :
1464 : static void
1465 23349721 : record_equivalences_from_incoming_edge (basic_block bb,
1466 : class const_and_copies *const_and_copies,
1467 : class avail_exprs_stack *avail_exprs_stack,
1468 : bitmap blocks_on_stack)
1469 : {
1470 23349721 : edge e;
1471 23349721 : basic_block parent;
1472 :
1473 : /* If our parent block ended with a control statement, then we may be
1474 : able to record some equivalences based on which outgoing edge from
1475 : the parent was followed. */
1476 23349721 : parent = get_immediate_dominator (CDI_DOMINATORS, bb);
1477 :
1478 23349721 : e = single_pred_edge_ignoring_loop_edges (bb, true);
1479 :
1480 : /* If we had a single incoming edge from our parent block, then enter
1481 : any data associated with the edge into our tables. */
1482 23349721 : if (e && e->src == parent)
1483 17347046 : record_temporary_equivalences (e, const_and_copies, avail_exprs_stack,
1484 : blocks_on_stack);
1485 23349721 : }
1486 :
1487 : /* Dump statistics for the hash table HTAB. */
1488 :
1489 : static void
1490 35 : htab_statistics (FILE *file, const hash_table<expr_elt_hasher> &htab)
1491 : {
1492 66 : fprintf (file, "size " HOST_SIZE_T_PRINT_DEC ", " HOST_SIZE_T_PRINT_DEC
1493 : " elements, %f collision/search ratio\n",
1494 35 : (fmt_size_t) htab.size (),
1495 35 : (fmt_size_t) htab.elements (),
1496 : htab.collisions ());
1497 35 : }
1498 :
1499 : /* Dump SSA statistics on FILE. */
1500 :
1501 : static void
1502 35 : dump_dominator_optimization_stats (FILE *file,
1503 : hash_table<expr_elt_hasher> *avail_exprs)
1504 : {
1505 35 : fprintf (file, "Total number of statements: %6ld\n\n",
1506 : opt_stats.num_stmts);
1507 35 : fprintf (file, "Exprs considered for dominator optimizations: %6ld\n",
1508 : opt_stats.num_exprs_considered);
1509 :
1510 35 : fprintf (file, "\nHash table statistics:\n");
1511 :
1512 35 : fprintf (file, " avail_exprs: ");
1513 35 : htab_statistics (file, *avail_exprs);
1514 35 : }
1515 :
1516 :
1517 : /* Similarly, but assume that X and Y are the two operands of an EQ_EXPR.
1518 : This constrains the cases in which we may treat this as assignment. */
1519 :
1520 : static void
1521 13119352 : record_equality (tree x, tree y, class const_and_copies *const_and_copies)
1522 : {
1523 13119352 : tree prev_x = NULL, prev_y = NULL;
1524 :
1525 13119352 : if (tree_swap_operands_p (x, y))
1526 596979 : std::swap (x, y);
1527 :
1528 : /* Most of the time tree_swap_operands_p does what we want. But there
1529 : are cases where we know one operand is better for copy propagation than
1530 : the other. Given no other code cares about ordering of equality
1531 : comparison operators for that purpose, we just handle the special cases
1532 : here. */
1533 13119352 : if (TREE_CODE (x) == SSA_NAME && TREE_CODE (y) == SSA_NAME)
1534 : {
1535 : /* If one operand is a single use operand, then make it
1536 : X. This will preserve its single use properly and if this
1537 : conditional is eliminated, the computation of X can be
1538 : eliminated as well. */
1539 1084281 : if (has_single_use (y) && ! has_single_use (x))
1540 : std::swap (x, y);
1541 : }
1542 13119352 : if (TREE_CODE (x) == SSA_NAME)
1543 13119352 : prev_x = SSA_NAME_VALUE (x);
1544 13119352 : if (TREE_CODE (y) == SSA_NAME)
1545 1084281 : prev_y = SSA_NAME_VALUE (y);
1546 :
1547 : /* If one of the previous values is invariant, or invariant in more loops
1548 : (by depth), then use that.
1549 : Otherwise it doesn't matter which value we choose, just so
1550 : long as we canonicalize on one value. */
1551 13119352 : if (is_gimple_min_invariant (y))
1552 : ;
1553 1084281 : else if (is_gimple_min_invariant (x))
1554 : prev_x = x, x = y, y = prev_x, prev_x = prev_y;
1555 1084281 : else if (prev_x && is_gimple_min_invariant (prev_x))
1556 : x = y, y = prev_x, prev_x = prev_y;
1557 996490 : else if (prev_y)
1558 13119352 : y = prev_y;
1559 :
1560 : /* After the swapping, we must have one SSA_NAME. */
1561 13119352 : if (TREE_CODE (x) != SSA_NAME)
1562 : return;
1563 :
1564 : /* For IEEE, -0.0 == 0.0, so we don't necessarily know the sign of a
1565 : variable compared against zero. If we're honoring signed zeros,
1566 : then we cannot record this value unless we know that the value is
1567 : nonzero. */
1568 13119352 : if (HONOR_SIGNED_ZEROS (x)
1569 13119352 : && (TREE_CODE (y) != REAL_CST
1570 170365 : || real_equal (&dconst0, &TREE_REAL_CST (y))))
1571 505 : return;
1572 :
1573 13118847 : const_and_copies->record_const_or_copy (x, y, prev_x);
1574 : }
1575 :
1576 : /* Returns true when STMT is a simple iv increment. It detects the
1577 : following situation:
1578 :
1579 : i_1 = phi (..., i_k)
1580 : [...]
1581 : i_j = i_{j-1} for each j : 2 <= j <= k-1
1582 : [...]
1583 : i_k = i_{k-1} +/- ... */
1584 :
1585 : bool
1586 42491068 : simple_iv_increment_p (gimple *stmt)
1587 : {
1588 42491068 : enum tree_code code;
1589 42491068 : tree lhs, preinc;
1590 42491068 : gimple *phi;
1591 42491068 : size_t i;
1592 :
1593 42491068 : if (gimple_code (stmt) != GIMPLE_ASSIGN)
1594 : return false;
1595 :
1596 32676242 : lhs = gimple_assign_lhs (stmt);
1597 32676242 : if (TREE_CODE (lhs) != SSA_NAME)
1598 : return false;
1599 :
1600 32676242 : code = gimple_assign_rhs_code (stmt);
1601 32676242 : if (code != PLUS_EXPR
1602 32676242 : && code != MINUS_EXPR
1603 32676242 : && code != POINTER_PLUS_EXPR)
1604 : return false;
1605 :
1606 7896368 : preinc = gimple_assign_rhs1 (stmt);
1607 7896368 : if (TREE_CODE (preinc) != SSA_NAME)
1608 : return false;
1609 :
1610 7620053 : phi = SSA_NAME_DEF_STMT (preinc);
1611 7645022 : while (gimple_code (phi) != GIMPLE_PHI)
1612 : {
1613 : /* Follow trivial copies, but not the DEF used in a back edge,
1614 : so that we don't prevent coalescing. */
1615 5192343 : if (!gimple_assign_ssa_name_copy_p (phi))
1616 : return false;
1617 24969 : preinc = gimple_assign_rhs1 (phi);
1618 24969 : phi = SSA_NAME_DEF_STMT (preinc);
1619 : }
1620 :
1621 4812844 : for (i = 0; i < gimple_phi_num_args (phi); i++)
1622 3892429 : if (gimple_phi_arg_def (phi, i) == lhs)
1623 : return true;
1624 :
1625 : return false;
1626 : }
1627 :
1628 : /* Propagate know values from SSA_NAME_VALUE into the PHI nodes of the
1629 : successors of BB. */
1630 :
1631 : static void
1632 23349721 : cprop_into_successor_phis (basic_block bb,
1633 : class const_and_copies *const_and_copies)
1634 : {
1635 23349721 : edge e;
1636 23349721 : edge_iterator ei;
1637 :
1638 55424921 : FOR_EACH_EDGE (e, ei, bb->succs)
1639 : {
1640 32075200 : int indx;
1641 32075200 : gphi_iterator gsi;
1642 :
1643 : /* If this is an abnormal edge, then we do not want to copy propagate
1644 : into the PHI alternative associated with this edge. */
1645 32075200 : if (e->flags & EDGE_ABNORMAL)
1646 18943406 : continue;
1647 :
1648 32061312 : gsi = gsi_start_phis (e->dest);
1649 32061312 : if (gsi_end_p (gsi))
1650 18929518 : continue;
1651 :
1652 : /* We may have an equivalence associated with this edge. While
1653 : we cannot propagate it into non-dominated blocks, we can
1654 : propagate them into PHIs in non-dominated blocks. */
1655 :
1656 : /* Push the unwind marker so we can reset the const and copies
1657 : table back to its original state after processing this edge. */
1658 13131794 : const_and_copies->push_marker ();
1659 :
1660 : /* Extract and record any simple NAME = VALUE equivalences.
1661 :
1662 : Don't bother with [01] = COND equivalences, they're not useful
1663 : here. */
1664 13131794 : class edge_info *edge_info = (class edge_info *) e->aux;
1665 :
1666 13131794 : if (edge_info)
1667 : {
1668 : edge_info::equiv_pair *seq;
1669 8227904 : for (int i = 0; edge_info->simple_equivalences.iterate (i, &seq); ++i)
1670 : {
1671 3129486 : tree lhs = seq->first;
1672 3129486 : tree rhs = seq->second;
1673 :
1674 3129486 : if (lhs && TREE_CODE (lhs) == SSA_NAME)
1675 3129486 : const_and_copies->record_const_or_copy (lhs, rhs);
1676 : }
1677 :
1678 : }
1679 :
1680 13131794 : indx = e->dest_idx;
1681 36024771 : for ( ; !gsi_end_p (gsi); gsi_next (&gsi))
1682 : {
1683 22892977 : tree new_val;
1684 22892977 : use_operand_p orig_p;
1685 22892977 : tree orig_val;
1686 22892977 : gphi *phi = gsi.phi ();
1687 :
1688 : /* The alternative may be associated with a constant, so verify
1689 : it is an SSA_NAME before doing anything with it. */
1690 22892977 : orig_p = gimple_phi_arg_imm_use_ptr (phi, indx);
1691 22892977 : orig_val = get_use_from_ptr (orig_p);
1692 22892977 : if (TREE_CODE (orig_val) != SSA_NAME)
1693 3131904 : continue;
1694 :
1695 : /* If we have *ORIG_P in our constant/copy table, then replace
1696 : ORIG_P with its value in our constant/copy table. */
1697 19761073 : new_val = SSA_NAME_VALUE (orig_val);
1698 19761073 : if (new_val
1699 19761073 : && new_val != orig_val
1700 19761073 : && may_propagate_copy (orig_val, new_val))
1701 1056934 : propagate_value (orig_p, new_val);
1702 : }
1703 :
1704 13131794 : const_and_copies->pop_to_marker ();
1705 : }
1706 23349721 : }
1707 :
1708 : edge
1709 23349721 : dom_opt_dom_walker::before_dom_children (basic_block bb)
1710 : {
1711 23349721 : gimple_stmt_iterator gsi;
1712 :
1713 23349721 : if (dump_file && (dump_flags & TDF_DETAILS))
1714 736 : fprintf (dump_file, "\n\nOptimizing block #%d\n\n", bb->index);
1715 :
1716 : /* Push a marker on the stacks of local information so that we know how
1717 : far to unwind when we finalize this block. */
1718 23349721 : m_avail_exprs_stack->push_marker ();
1719 23349721 : m_const_and_copies->push_marker ();
1720 23349721 : bitmap_set_bit (m_state->get_blocks_on_stack (), bb->index);
1721 :
1722 23349721 : record_equivalences_from_incoming_edge (bb, m_const_and_copies,
1723 : m_avail_exprs_stack,
1724 23349721 : m_state->get_blocks_on_stack ());
1725 23349721 : set_global_ranges_from_unreachable_edges (bb);
1726 :
1727 : /* PHI nodes can create equivalences too. */
1728 23349721 : record_equivalences_from_phis (bb);
1729 :
1730 : /* Create equivalences from redundant PHIs. PHIs are only truly
1731 : redundant when they exist in the same block, so push another
1732 : marker and unwind right afterwards. */
1733 23349721 : m_avail_exprs_stack->push_marker ();
1734 31971644 : for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1735 8621923 : eliminate_redundant_computations (&gsi, m_const_and_copies,
1736 : m_avail_exprs_stack);
1737 23349721 : m_avail_exprs_stack->pop_to_marker ();
1738 :
1739 23349721 : edge taken_edge = NULL;
1740 : /* Initialize visited flag ahead of us, it has undefined state on
1741 : pass entry. */
1742 218103537 : for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1743 171404095 : gimple_set_visited (gsi_stmt (gsi), false);
1744 366036677 : for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
1745 : {
1746 : /* Do not optimize a stmt twice, substitution might end up with
1747 : _3 = _3 which is not valid. */
1748 342686956 : if (gimple_visited_p (gsi_stmt (gsi)))
1749 : {
1750 171282660 : gsi_next (&gsi);
1751 171282660 : continue;
1752 : }
1753 :
1754 171404296 : bool removed_p = false;
1755 171404296 : taken_edge = this->optimize_stmt (bb, &gsi, &removed_p);
1756 171404296 : if (!removed_p)
1757 171282660 : gimple_set_visited (gsi_stmt (gsi), true);
1758 :
1759 : /* Go back and visit stmts inserted by folding after substituting
1760 : into the stmt at gsi. */
1761 171404296 : if (gsi_end_p (gsi))
1762 : {
1763 2787 : gcc_checking_assert (removed_p);
1764 2787 : gsi = gsi_last_bb (bb);
1765 5174 : while (!gsi_end_p (gsi) && !gimple_visited_p (gsi_stmt (gsi)))
1766 2787 : gsi_prev (&gsi);
1767 : }
1768 : else
1769 : {
1770 171401710 : do
1771 : {
1772 171401710 : gsi_prev (&gsi);
1773 : }
1774 342803219 : while (!gsi_end_p (gsi) && !gimple_visited_p (gsi_stmt (gsi)));
1775 : }
1776 171404296 : if (gsi_end_p (gsi))
1777 38474694 : gsi = gsi_start_bb (bb);
1778 : else
1779 152166949 : gsi_next (&gsi);
1780 : }
1781 :
1782 : /* Now prepare to process dominated blocks. */
1783 23349721 : record_edge_info (bb);
1784 23349721 : cprop_into_successor_phis (bb, m_const_and_copies);
1785 23349721 : if (taken_edge && !dbg_cnt (dom_unreachable_edges))
1786 : return NULL;
1787 :
1788 : return taken_edge;
1789 : }
1790 :
1791 : /* We have finished processing the dominator children of BB, perform
1792 : any finalization actions in preparation for leaving this node in
1793 : the dominator tree. */
1794 :
1795 : void
1796 23349721 : dom_opt_dom_walker::after_dom_children (basic_block bb)
1797 : {
1798 23349721 : m_threader->thread_outgoing_edges (bb);
1799 23349721 : bitmap_clear_bit (m_state->get_blocks_on_stack (), bb->index);
1800 23349721 : m_avail_exprs_stack->pop_to_marker ();
1801 23349721 : m_const_and_copies->pop_to_marker ();
1802 23349721 : }
1803 :
1804 : /* Search for redundant computations in STMT. If any are found, then
1805 : replace them with the variable holding the result of the computation.
1806 :
1807 : If safe, record this expression into AVAIL_EXPRS_STACK and
1808 : CONST_AND_COPIES. */
1809 :
1810 : static void
1811 62973264 : eliminate_redundant_computations (gimple_stmt_iterator* gsi,
1812 : class const_and_copies *const_and_copies,
1813 : class avail_exprs_stack *avail_exprs_stack)
1814 : {
1815 62973264 : tree expr_type;
1816 62973264 : tree cached_lhs;
1817 62973264 : tree def;
1818 62973264 : bool insert = true;
1819 62973264 : bool assigns_var_p = false;
1820 :
1821 62973264 : gimple *stmt = gsi_stmt (*gsi);
1822 :
1823 62973264 : if (gimple_code (stmt) == GIMPLE_PHI)
1824 8621923 : def = gimple_phi_result (stmt);
1825 : else
1826 54351341 : def = gimple_get_lhs (stmt);
1827 :
1828 : /* Certain expressions on the RHS can be optimized away, but cannot
1829 : themselves be entered into the hash tables. */
1830 62973264 : if (! def
1831 54030296 : || TREE_CODE (def) != SSA_NAME
1832 41397223 : || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def)
1833 32774027 : || gimple_vdef (stmt)
1834 : /* Do not record equivalences for increments of ivs. This would create
1835 : overlapping live ranges for a very questionable gain. */
1836 104359857 : || simple_iv_increment_p (stmt))
1837 : insert = false;
1838 :
1839 : /* Check if the expression has been computed before. */
1840 62973264 : cached_lhs = avail_exprs_stack->lookup_avail_expr (stmt, insert, true);
1841 :
1842 62973264 : opt_stats.num_exprs_considered++;
1843 :
1844 : /* Get the type of the expression we are trying to optimize. */
1845 62973264 : if (is_gimple_assign (stmt))
1846 : {
1847 44156507 : expr_type = TREE_TYPE (gimple_assign_lhs (stmt));
1848 44156507 : assigns_var_p = true;
1849 : }
1850 18816757 : else if (gimple_code (stmt) == GIMPLE_COND)
1851 8909949 : expr_type = boolean_type_node;
1852 9906808 : else if (is_gimple_call (stmt))
1853 : {
1854 1251866 : gcc_assert (gimple_call_lhs (stmt));
1855 1251866 : expr_type = TREE_TYPE (gimple_call_lhs (stmt));
1856 1251866 : assigns_var_p = true;
1857 : }
1858 8654942 : else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt))
1859 33019 : expr_type = TREE_TYPE (gimple_switch_index (swtch_stmt));
1860 8621923 : else if (gimple_code (stmt) == GIMPLE_PHI)
1861 : /* We can't propagate into a phi, so the logic below doesn't apply.
1862 : Instead record an equivalence between the cached LHS and the
1863 : PHI result of this statement, provided they are in the same block.
1864 : This should be sufficient to kill the redundant phi. */
1865 : {
1866 8621923 : if (def && cached_lhs)
1867 20218 : const_and_copies->record_const_or_copy (def, cached_lhs);
1868 8621923 : return;
1869 : }
1870 : else
1871 0 : gcc_unreachable ();
1872 :
1873 54351341 : if (!cached_lhs)
1874 : return;
1875 :
1876 : /* It is safe to ignore types here since we have already done
1877 : type checking in the hashing and equality routines. In fact
1878 : type checking here merely gets in the way of constant
1879 : propagation. Also, make sure that it is safe to propagate
1880 : CACHED_LHS into the expression in STMT. */
1881 427309 : if ((TREE_CODE (cached_lhs) != SSA_NAME
1882 38317 : && (assigns_var_p
1883 3378 : || useless_type_conversion_p (expr_type, TREE_TYPE (cached_lhs))))
1884 427309 : || may_propagate_copy_into_stmt (stmt, cached_lhs))
1885 : {
1886 414037 : gcc_checking_assert (TREE_CODE (cached_lhs) == SSA_NAME
1887 : || is_gimple_min_invariant (cached_lhs));
1888 :
1889 414037 : if (dump_file && (dump_flags & TDF_DETAILS))
1890 : {
1891 16 : fprintf (dump_file, " Replaced redundant expr '");
1892 16 : print_gimple_expr (dump_file, stmt, 0, dump_flags);
1893 16 : fprintf (dump_file, "' with '");
1894 16 : print_generic_expr (dump_file, cached_lhs, dump_flags);
1895 16 : fprintf (dump_file, "'\n");
1896 : }
1897 :
1898 414037 : opt_stats.num_re++;
1899 :
1900 414037 : if (assigns_var_p
1901 414037 : && !useless_type_conversion_p (expr_type, TREE_TYPE (cached_lhs)))
1902 0 : cached_lhs = fold_convert (expr_type, cached_lhs);
1903 :
1904 414037 : propagate_tree_value_into_stmt (gsi, cached_lhs);
1905 :
1906 : /* Since it is always necessary to mark the result as modified,
1907 : perhaps we should move this into propagate_tree_value_into_stmt
1908 : itself. */
1909 414037 : gimple_set_modified (gsi_stmt (*gsi), true);
1910 : }
1911 : }
1912 :
1913 : /* STMT, a GIMPLE_ASSIGN, may create certain equivalences, in either
1914 : the available expressions table or the const_and_copies table.
1915 : Detect and record those equivalences into AVAIL_EXPRS_STACK.
1916 :
1917 : We handle only very simple copy equivalences here. The heavy
1918 : lifing is done by eliminate_redundant_computations. */
1919 :
1920 : static void
1921 47527751 : record_equivalences_from_stmt (gimple *stmt, int may_optimize_p,
1922 : class avail_exprs_stack *avail_exprs_stack)
1923 : {
1924 47527751 : tree lhs;
1925 47527751 : enum tree_code lhs_code;
1926 :
1927 47527751 : gcc_assert (is_gimple_assign (stmt));
1928 :
1929 47527751 : lhs = gimple_assign_lhs (stmt);
1930 47527751 : lhs_code = TREE_CODE (lhs);
1931 :
1932 47527751 : if (lhs_code == SSA_NAME
1933 47527751 : && gimple_assign_single_p (stmt))
1934 : {
1935 15603243 : tree rhs = gimple_assign_rhs1 (stmt);
1936 :
1937 : /* If the RHS of the assignment is a constant or another variable that
1938 : may be propagated, register it in the CONST_AND_COPIES table. We
1939 : do not need to record unwind data for this, since this is a true
1940 : assignment and not an equivalence inferred from a comparison. All
1941 : uses of this ssa name are dominated by this assignment, so unwinding
1942 : just costs time and space. */
1943 15603243 : if (may_optimize_p
1944 15603243 : && (TREE_CODE (rhs) == SSA_NAME
1945 13574516 : || is_gimple_min_invariant (rhs)))
1946 : {
1947 1983554 : rhs = dom_valueize (rhs);
1948 :
1949 1983554 : if (dump_file && (dump_flags & TDF_DETAILS))
1950 : {
1951 74 : fprintf (dump_file, "==== ASGN ");
1952 74 : print_generic_expr (dump_file, lhs);
1953 74 : fprintf (dump_file, " = ");
1954 74 : print_generic_expr (dump_file, rhs);
1955 74 : fprintf (dump_file, "\n");
1956 : }
1957 :
1958 1983554 : set_ssa_name_value (lhs, rhs);
1959 : }
1960 : }
1961 :
1962 : /* Make sure we can propagate &x + CST. */
1963 47527751 : if (lhs_code == SSA_NAME
1964 32159215 : && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
1965 1624260 : && TREE_CODE (gimple_assign_rhs1 (stmt)) == ADDR_EXPR
1966 47718370 : && TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST)
1967 : {
1968 4280 : tree op0 = gimple_assign_rhs1 (stmt);
1969 4280 : tree op1 = gimple_assign_rhs2 (stmt);
1970 4280 : tree new_rhs
1971 8560 : = build1 (ADDR_EXPR, TREE_TYPE (op0),
1972 4280 : fold_build2 (MEM_REF, TREE_TYPE (TREE_TYPE (op0)),
1973 : unshare_expr (op0), fold_convert (ptr_type_node,
1974 : op1)));
1975 4280 : if (dump_file && (dump_flags & TDF_DETAILS))
1976 : {
1977 0 : fprintf (dump_file, "==== ASGN ");
1978 0 : print_generic_expr (dump_file, lhs);
1979 0 : fprintf (dump_file, " = ");
1980 0 : print_generic_expr (dump_file, new_rhs);
1981 0 : fprintf (dump_file, "\n");
1982 : }
1983 :
1984 4280 : set_ssa_name_value (lhs, new_rhs);
1985 : }
1986 :
1987 : /* A memory store, even an aliased store, creates a useful
1988 : equivalence. By exchanging the LHS and RHS, creating suitable
1989 : vops and recording the result in the available expression table,
1990 : we may be able to expose more redundant loads. */
1991 91568078 : if (!gimple_has_volatile_ops (stmt)
1992 71492032 : && gimple_references_memory_p (stmt)
1993 23964281 : && gimple_assign_single_p (stmt)
1994 23964281 : && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
1995 18739506 : || is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
1996 59032610 : && !is_gimple_reg (lhs))
1997 : {
1998 11334168 : tree rhs = gimple_assign_rhs1 (stmt);
1999 11334168 : gassign *new_stmt;
2000 :
2001 : /* Build a new statement with the RHS and LHS exchanged. */
2002 11334168 : if (TREE_CODE (rhs) == SSA_NAME)
2003 : {
2004 : /* NOTE tuples. The call to gimple_build_assign below replaced
2005 : a call to build_gimple_modify_stmt, which did not set the
2006 : SSA_NAME_DEF_STMT on the LHS of the assignment. Doing so
2007 : may cause an SSA validation failure, as the LHS may be a
2008 : default-initialized name and should have no definition. I'm
2009 : a bit dubious of this, as the artificial statement that we
2010 : generate here may in fact be ill-formed, but it is simply
2011 : used as an internal device in this pass, and never becomes
2012 : part of the CFG. */
2013 5084555 : gimple *defstmt = SSA_NAME_DEF_STMT (rhs);
2014 5084555 : new_stmt = gimple_build_assign (rhs, lhs);
2015 5084555 : SSA_NAME_DEF_STMT (rhs) = defstmt;
2016 : }
2017 : else
2018 6249613 : new_stmt = gimple_build_assign (rhs, lhs);
2019 :
2020 22668336 : gimple_set_vuse (new_stmt, gimple_vdef (stmt));
2021 :
2022 : /* Finally enter the statement into the available expression
2023 : table. */
2024 11334168 : avail_exprs_stack->lookup_avail_expr (new_stmt, true, true);
2025 : }
2026 47527751 : }
2027 :
2028 : /* Replace *OP_P in STMT with any known equivalent value for *OP_P from
2029 : CONST_AND_COPIES. */
2030 :
2031 : static void
2032 79518347 : cprop_operand (gimple *stmt, use_operand_p op_p, range_query *query)
2033 : {
2034 79518347 : tree val;
2035 79518347 : tree op = USE_FROM_PTR (op_p);
2036 :
2037 : /* If the operand has a known constant value or it is known to be a
2038 : copy of some other variable, use the value or copy stored in
2039 : CONST_AND_COPIES. */
2040 79518347 : val = SSA_NAME_VALUE (op);
2041 53437367 : if (!val)
2042 : {
2043 75688580 : value_range r (TREE_TYPE (op));
2044 75688580 : tree single;
2045 149084810 : if (query->range_of_expr (r, op, stmt) && r.singleton_p (&single))
2046 22999 : val = single;
2047 75688580 : }
2048 :
2049 79518347 : if (val && val != op)
2050 : {
2051 : /* Certain operands are not allowed to be copy propagated due
2052 : to their interaction with exception handling and some GCC
2053 : extensions. */
2054 3851036 : if (!may_propagate_copy (op, val))
2055 : return;
2056 :
2057 : /* Do not propagate copies into BIVs.
2058 : See PR23821 and PR62217 for how this can disturb IV and
2059 : number of iteration analysis. */
2060 3849473 : if (TREE_CODE (val) != INTEGER_CST)
2061 : {
2062 3144729 : gimple *def = SSA_NAME_DEF_STMT (op);
2063 3144729 : if (gimple_code (def) == GIMPLE_PHI
2064 3144729 : && gimple_bb (def)->loop_father->header == gimple_bb (def))
2065 : return;
2066 : }
2067 :
2068 : /* Dump details. */
2069 3839464 : if (dump_file && (dump_flags & TDF_DETAILS))
2070 : {
2071 76 : fprintf (dump_file, " Replaced '");
2072 76 : print_generic_expr (dump_file, op, dump_flags);
2073 76 : fprintf (dump_file, "' with %s '",
2074 76 : (TREE_CODE (val) != SSA_NAME ? "constant" : "variable"));
2075 76 : print_generic_expr (dump_file, val, dump_flags);
2076 76 : fprintf (dump_file, "'\n");
2077 : }
2078 :
2079 3839464 : if (TREE_CODE (val) != SSA_NAME)
2080 877958 : opt_stats.num_const_prop++;
2081 : else
2082 2961506 : opt_stats.num_copy_prop++;
2083 :
2084 3839464 : propagate_value (op_p, val);
2085 :
2086 : /* And note that we modified this statement. This is now
2087 : safe, even if we changed virtual operands since we will
2088 : rescan the statement and rewrite its operands again. */
2089 3839464 : gimple_set_modified (stmt, true);
2090 : }
2091 : }
2092 :
2093 : /* CONST_AND_COPIES is a table which maps an SSA_NAME to the current
2094 : known value for that SSA_NAME (or NULL if no value is known).
2095 :
2096 : Propagate values from CONST_AND_COPIES into the uses, vuses and
2097 : vdef_ops of STMT. */
2098 :
2099 : static void
2100 171404296 : cprop_into_stmt (gimple *stmt, range_query *query)
2101 : {
2102 171404296 : use_operand_p op_p;
2103 171404296 : ssa_op_iter iter;
2104 171404296 : tree last_copy_propagated_op = NULL;
2105 :
2106 250923246 : FOR_EACH_SSA_USE_OPERAND (op_p, stmt, iter, SSA_OP_USE)
2107 : {
2108 79518950 : tree old_op = USE_FROM_PTR (op_p);
2109 :
2110 : /* If we have A = B and B = A in the copy propagation tables
2111 : (due to an equality comparison), avoid substituting B for A
2112 : then A for B in the trivially discovered cases. This allows
2113 : optimization of statements were A and B appear as input
2114 : operands. */
2115 79518950 : if (old_op != last_copy_propagated_op)
2116 : {
2117 79518347 : cprop_operand (stmt, op_p, query);
2118 :
2119 79518347 : tree new_op = USE_FROM_PTR (op_p);
2120 79518347 : if (new_op != old_op && TREE_CODE (new_op) == SSA_NAME)
2121 79518950 : last_copy_propagated_op = new_op;
2122 : }
2123 : }
2124 171404296 : }
2125 :
2126 : /* If STMT contains a relational test, try to convert it into an
2127 : equality test if there is only a single value which can ever
2128 : make the test true.
2129 :
2130 : For example, if the expression hash table contains:
2131 :
2132 : TRUE = (i <= 1)
2133 :
2134 : And we have a test within statement of i >= 1, then we can safely
2135 : rewrite the test as i == 1 since there only a single value where
2136 : the test is true.
2137 :
2138 : This is similar to code in VRP. */
2139 :
2140 : void
2141 54229705 : dom_opt_dom_walker::test_for_singularity (gimple *stmt,
2142 : avail_exprs_stack *avail_exprs_stack)
2143 : {
2144 : /* We want to support gimple conditionals as well as assignments
2145 : where the RHS contains a conditional. */
2146 54229705 : if (is_gimple_assign (stmt) || gimple_code (stmt) == GIMPLE_COND)
2147 : {
2148 52950276 : enum tree_code code = ERROR_MARK;
2149 52950276 : tree lhs, rhs;
2150 :
2151 : /* Extract the condition of interest from both forms we support. */
2152 52950276 : if (is_gimple_assign (stmt))
2153 : {
2154 44040327 : code = gimple_assign_rhs_code (stmt);
2155 44040327 : lhs = gimple_assign_rhs1 (stmt);
2156 44040327 : rhs = gimple_assign_rhs2 (stmt);
2157 : }
2158 8909949 : else if (gimple_code (stmt) == GIMPLE_COND)
2159 : {
2160 8909949 : code = gimple_cond_code (as_a <gcond *> (stmt));
2161 8909949 : lhs = gimple_cond_lhs (as_a <gcond *> (stmt));
2162 8909949 : rhs = gimple_cond_rhs (as_a <gcond *> (stmt));
2163 : }
2164 :
2165 : /* We're looking for a relational test using LE/GE. Also note we can
2166 : canonicalize LT/GT tests against constants into LE/GT tests. */
2167 52950276 : if (code == LE_EXPR || code == GE_EXPR
2168 52287820 : || ((code == LT_EXPR || code == GT_EXPR)
2169 1706538 : && TREE_CODE (rhs) == INTEGER_CST))
2170 : {
2171 : /* For LT_EXPR and GT_EXPR, canonicalize to LE_EXPR and GE_EXPR. */
2172 905406 : if (code == LT_EXPR)
2173 132856 : rhs = fold_build2 (MINUS_EXPR, TREE_TYPE (rhs),
2174 : rhs, build_int_cst (TREE_TYPE (rhs), 1));
2175 :
2176 1567862 : if (code == GT_EXPR)
2177 772550 : rhs = fold_build2 (PLUS_EXPR, TREE_TYPE (rhs),
2178 : rhs, build_int_cst (TREE_TYPE (rhs), 1));
2179 :
2180 : /* Determine the code we want to check for in the hash table. */
2181 1567862 : enum tree_code test_code;
2182 1567862 : if (code == GE_EXPR || code == GT_EXPR)
2183 : test_code = LE_EXPR;
2184 : else
2185 537493 : test_code = GE_EXPR;
2186 :
2187 : /* Update the dummy statement so we can query the hash tables. */
2188 1567862 : gimple_cond_set_code (m_dummy_cond, test_code);
2189 1567862 : gimple_cond_set_lhs (m_dummy_cond, lhs);
2190 1567862 : gimple_cond_set_rhs (m_dummy_cond, rhs);
2191 1567862 : tree cached_lhs
2192 1567862 : = avail_exprs_stack->lookup_avail_expr (m_dummy_cond,
2193 : false, false);
2194 :
2195 : /* If the lookup returned 1 (true), then the expression we
2196 : queried was in the hash table. As a result there is only
2197 : one value that makes the original conditional true. Update
2198 : STMT accordingly. */
2199 1567862 : if (cached_lhs && integer_onep (cached_lhs))
2200 : {
2201 1357 : if (is_gimple_assign (stmt))
2202 : {
2203 96 : gimple_assign_set_rhs_code (stmt, EQ_EXPR);
2204 96 : gimple_assign_set_rhs2 (stmt, rhs);
2205 96 : gimple_set_modified (stmt, true);
2206 : }
2207 : else
2208 : {
2209 1261 : gimple_set_modified (stmt, true);
2210 1261 : gimple_cond_set_code (as_a <gcond *> (stmt), EQ_EXPR);
2211 1261 : gimple_cond_set_rhs (as_a <gcond *> (stmt), rhs);
2212 1261 : gimple_set_modified (stmt, true);
2213 : }
2214 : }
2215 : }
2216 : }
2217 54229705 : }
2218 :
2219 : /* If STMT is a comparison of two uniform vectors reduce it to a comparison
2220 : of scalar objects, otherwise leave STMT unchanged. */
2221 :
2222 : static void
2223 171404296 : reduce_vector_comparison_to_scalar_comparison (gimple *stmt)
2224 : {
2225 171404296 : if (gimple_code (stmt) == GIMPLE_COND)
2226 : {
2227 9012414 : tree lhs = gimple_cond_lhs (stmt);
2228 9012414 : tree rhs = gimple_cond_rhs (stmt);
2229 :
2230 : /* We may have a vector comparison where both arms are uniform
2231 : vectors. If so, we can simplify the vector comparison down
2232 : to a scalar comparison. */
2233 9012414 : if (VECTOR_TYPE_P (TREE_TYPE (lhs))
2234 9012414 : && VECTOR_TYPE_P (TREE_TYPE (rhs)))
2235 : {
2236 : /* If either operand is an SSA_NAME, then look back to its
2237 : defining statement to try and get at a suitable source. */
2238 2497 : if (TREE_CODE (rhs) == SSA_NAME)
2239 : {
2240 0 : gimple *def_stmt = SSA_NAME_DEF_STMT (rhs);
2241 0 : if (gimple_assign_single_p (def_stmt))
2242 0 : rhs = gimple_assign_rhs1 (def_stmt);
2243 : }
2244 :
2245 2497 : if (TREE_CODE (lhs) == SSA_NAME)
2246 : {
2247 2497 : gimple *def_stmt = SSA_NAME_DEF_STMT (lhs);
2248 2497 : if (gimple_assign_single_p (def_stmt))
2249 6 : lhs = gimple_assign_rhs1 (def_stmt);
2250 : }
2251 :
2252 : /* Now see if they are both uniform vectors and if so replace
2253 : the vector comparison with a scalar comparison. */
2254 2497 : tree rhs_elem = rhs ? uniform_vector_p (rhs) : NULL_TREE;
2255 2497 : tree lhs_elem = lhs ? uniform_vector_p (lhs) : NULL_TREE;
2256 2497 : if (rhs_elem && lhs_elem)
2257 : {
2258 3 : if (dump_file && dump_flags & TDF_DETAILS)
2259 : {
2260 0 : fprintf (dump_file, "Reducing vector comparison: ");
2261 0 : print_gimple_stmt (dump_file, stmt, 0);
2262 : }
2263 :
2264 3 : gimple_cond_set_rhs (as_a <gcond *>(stmt), rhs_elem);
2265 3 : gimple_cond_set_lhs (as_a <gcond *>(stmt), lhs_elem);
2266 3 : gimple_set_modified (stmt, true);
2267 :
2268 3 : if (dump_file && dump_flags & TDF_DETAILS)
2269 : {
2270 0 : fprintf (dump_file, "To scalar equivalent: ");
2271 0 : print_gimple_stmt (dump_file, stmt, 0);
2272 0 : fprintf (dump_file, "\n");
2273 : }
2274 : }
2275 : }
2276 : }
2277 171404296 : }
2278 :
2279 : /* If possible, rewrite the conditional as TRUE or FALSE, and return
2280 : the taken edge. Otherwise, return NULL. */
2281 :
2282 : edge
2283 8951146 : dom_opt_dom_walker::fold_cond (gcond *cond)
2284 : {
2285 8951146 : simplify_using_ranges simplify (m_ranger);
2286 8951146 : if (simplify.fold_cond (cond))
2287 : {
2288 102465 : basic_block bb = gimple_bb (cond);
2289 102465 : if (gimple_cond_true_p (cond))
2290 23595 : return find_taken_edge (bb, boolean_true_node);
2291 78870 : if (gimple_cond_false_p (cond))
2292 78870 : return find_taken_edge (bb, boolean_false_node);
2293 : }
2294 : return NULL;
2295 8951146 : }
2296 :
2297 : /* Optimize the statement in block BB pointed to by iterator SI.
2298 :
2299 : We try to perform some simplistic global redundancy elimination and
2300 : constant propagation:
2301 :
2302 : 1- To detect global redundancy, we keep track of expressions that have
2303 : been computed in this block and its dominators. If we find that the
2304 : same expression is computed more than once, we eliminate repeated
2305 : computations by using the target of the first one.
2306 :
2307 : 2- Constant values and copy assignments. This is used to do very
2308 : simplistic constant and copy propagation. When a constant or copy
2309 : assignment is found, we map the value on the RHS of the assignment to
2310 : the variable in the LHS in the CONST_AND_COPIES table.
2311 :
2312 : 3- Very simple redundant store elimination is performed.
2313 :
2314 : 4- We can simplify a condition to a constant or from a relational
2315 : condition to an equality condition. */
2316 :
2317 : edge
2318 171404296 : dom_opt_dom_walker::optimize_stmt (basic_block bb, gimple_stmt_iterator *si,
2319 : bool *removed_p)
2320 : {
2321 171404296 : gimple *stmt, *old_stmt;
2322 171404296 : bool may_optimize_p;
2323 171404296 : bool modified_p = false;
2324 171404296 : bool was_noreturn;
2325 171404296 : edge retval = NULL;
2326 :
2327 171404296 : old_stmt = stmt = gsi_stmt (*si);
2328 171404296 : was_noreturn = is_gimple_call (stmt) && gimple_call_noreturn_p (stmt);
2329 :
2330 171404296 : if (dump_file && (dump_flags & TDF_DETAILS))
2331 : {
2332 1606 : fprintf (dump_file, "Optimizing statement ");
2333 1606 : print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
2334 : }
2335 :
2336 : /* STMT may be a comparison of uniform vectors that we can simplify
2337 : down to a comparison of scalars. Do that transformation first
2338 : so that all the scalar optimizations from here onward apply. */
2339 171404296 : reduce_vector_comparison_to_scalar_comparison (stmt);
2340 :
2341 171404296 : update_stmt_if_modified (stmt);
2342 171404296 : opt_stats.num_stmts++;
2343 :
2344 : /* Const/copy propagate into USES, VUSES and the RHS of VDEFs. */
2345 171404296 : cprop_into_stmt (stmt, m_ranger);
2346 :
2347 : /* If the statement has been modified with constant replacements,
2348 : fold its RHS before checking for redundant computations. */
2349 342507665 : if (gimple_modified_p (stmt))
2350 : {
2351 3679484 : tree rhs = NULL;
2352 :
2353 : /* Try to fold the statement making sure that STMT is kept
2354 : up to date. */
2355 3679484 : if (fold_stmt (si))
2356 : {
2357 374618 : stmt = gsi_stmt (*si);
2358 374618 : gimple_set_modified (stmt, true);
2359 :
2360 374618 : if (dump_file && (dump_flags & TDF_DETAILS))
2361 : {
2362 12 : fprintf (dump_file, " Folded to: ");
2363 12 : print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
2364 : }
2365 : }
2366 :
2367 : /* We only need to consider cases that can yield a gimple operand. */
2368 3679484 : if (gimple_assign_single_p (stmt))
2369 1386411 : rhs = gimple_assign_rhs1 (stmt);
2370 2293073 : else if (gimple_code (stmt) == GIMPLE_GOTO)
2371 1 : rhs = gimple_goto_dest (stmt);
2372 173697368 : else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt))
2373 : /* This should never be an ADDR_EXPR. */
2374 2130 : rhs = gimple_switch_index (swtch_stmt);
2375 :
2376 1388542 : if (rhs && TREE_CODE (rhs) == ADDR_EXPR)
2377 80021 : recompute_tree_invariant_for_addr_expr (rhs);
2378 :
2379 : /* Indicate that maybe_clean_or_replace_eh_stmt needs to be called,
2380 : even if fold_stmt updated the stmt already and thus cleared
2381 : gimple_modified_p flag on it. */
2382 : modified_p = true;
2383 : }
2384 :
2385 : /* Check for redundant computations. Do this optimization only
2386 : for assignments that have no volatile ops and conditionals. */
2387 171404296 : may_optimize_p = (!gimple_has_side_effects (stmt)
2388 171404296 : && (is_gimple_assign (stmt)
2389 114164735 : || (is_gimple_call (stmt)
2390 1254103 : && gimple_call_lhs (stmt) != NULL_TREE)
2391 112910961 : || gimple_code (stmt) == GIMPLE_COND
2392 103898547 : || gimple_code (stmt) == GIMPLE_SWITCH));
2393 :
2394 54453806 : if (may_optimize_p)
2395 : {
2396 54453806 : if (gimple_code (stmt) == GIMPLE_CALL)
2397 : {
2398 : /* Resolve __builtin_constant_p. If it hasn't been
2399 : folded to integer_one_node by now, it's fairly
2400 : certain that the value simply isn't constant. */
2401 1253774 : tree callee = gimple_call_fndecl (stmt);
2402 1253774 : if (callee
2403 1253774 : && fndecl_built_in_p (callee, BUILT_IN_CONSTANT_P))
2404 : {
2405 1908 : propagate_tree_value_into_stmt (si, integer_zero_node);
2406 1908 : stmt = gsi_stmt (*si);
2407 : }
2408 : }
2409 :
2410 54453806 : if (gimple_code (stmt) == GIMPLE_COND)
2411 : {
2412 9012414 : tree lhs = gimple_cond_lhs (stmt);
2413 9012414 : tree rhs = gimple_cond_rhs (stmt);
2414 :
2415 : /* If the LHS has a range [0..1] and the RHS has a range ~[0..1],
2416 : then this conditional is computable at compile time. We can just
2417 : shove either 0 or 1 into the LHS, mark the statement as modified
2418 : and all the right things will just happen below.
2419 :
2420 : Note this would apply to any case where LHS has a range
2421 : narrower than its type implies and RHS is outside that
2422 : narrower range. Future work. */
2423 9012414 : if (TREE_CODE (lhs) == SSA_NAME
2424 8951170 : && ssa_name_has_boolean_range (lhs)
2425 1006681 : && TREE_CODE (rhs) == INTEGER_CST
2426 9987783 : && ! (integer_zerop (rhs) || integer_onep (rhs)))
2427 : {
2428 24 : gimple_cond_set_lhs (as_a <gcond *> (stmt),
2429 24 : fold_convert (TREE_TYPE (lhs),
2430 : integer_zero_node));
2431 24 : gimple_set_modified (stmt, true);
2432 : }
2433 9012390 : else if (TREE_CODE (lhs) == SSA_NAME)
2434 : {
2435 : /* Exploiting EVRP data is not yet fully integrated into DOM
2436 : but we need to do something for this case to avoid regressing
2437 : udr4.f90 and new1.C which have unexecutable blocks with
2438 : undefined behavior that get diagnosed if they're left in the
2439 : IL because we've attached range information to new
2440 : SSA_NAMES. */
2441 8951146 : update_stmt_if_modified (stmt);
2442 8951146 : edge taken_edge = fold_cond (as_a <gcond *> (stmt));
2443 8951146 : if (taken_edge)
2444 : {
2445 102465 : gimple_set_modified (stmt, true);
2446 102465 : update_stmt (stmt);
2447 102465 : cfg_altered = true;
2448 102465 : return taken_edge;
2449 : }
2450 : }
2451 : }
2452 :
2453 54351341 : update_stmt_if_modified (stmt);
2454 54351341 : eliminate_redundant_computations (si, m_const_and_copies,
2455 : m_avail_exprs_stack);
2456 54351341 : stmt = gsi_stmt (*si);
2457 :
2458 : /* Perform simple redundant store elimination. */
2459 54351341 : if (gimple_assign_single_p (stmt)
2460 27605991 : && TREE_CODE (gimple_assign_lhs (stmt)) != SSA_NAME
2461 66934856 : && (TREE_CODE (gimple_assign_lhs (stmt)) != VAR_DECL
2462 1013980 : || !DECL_HARD_REGISTER (gimple_assign_lhs (stmt))))
2463 : {
2464 12581497 : tree lhs = gimple_assign_lhs (stmt);
2465 12581497 : tree rhs = gimple_assign_rhs1 (stmt);
2466 12581497 : tree cached_lhs;
2467 12581497 : gassign *new_stmt;
2468 12581497 : rhs = dom_valueize (rhs);
2469 : /* Build a new statement with the RHS and LHS exchanged. */
2470 12581497 : if (TREE_CODE (rhs) == SSA_NAME)
2471 : {
2472 5202390 : gimple *defstmt = SSA_NAME_DEF_STMT (rhs);
2473 5202390 : new_stmt = gimple_build_assign (rhs, lhs);
2474 5202390 : SSA_NAME_DEF_STMT (rhs) = defstmt;
2475 : }
2476 : else
2477 7379107 : new_stmt = gimple_build_assign (rhs, lhs);
2478 25162994 : gimple_set_vuse (new_stmt, gimple_vuse (stmt));
2479 12581497 : expr_hash_elt *elt = NULL;
2480 12581497 : cached_lhs = m_avail_exprs_stack->lookup_avail_expr (new_stmt, false,
2481 : false, &elt);
2482 12581497 : if (cached_lhs
2483 823682 : && operand_equal_p (rhs, cached_lhs, 0)
2484 12830219 : && refs_same_for_tbaa_p (elt->expr ()->kind == EXPR_SINGLE
2485 124361 : ? elt->expr ()->ops.single.rhs
2486 : : NULL_TREE, lhs))
2487 : {
2488 121636 : basic_block bb = gimple_bb (stmt);
2489 121636 : unlink_stmt_vdef (stmt);
2490 121636 : if (gsi_remove (si, true))
2491 : {
2492 0 : bitmap_set_bit (need_eh_cleanup, bb->index);
2493 0 : if (dump_file && (dump_flags & TDF_DETAILS))
2494 0 : fprintf (dump_file, " Flagged to clear EH edges.\n");
2495 : }
2496 121636 : release_defs (stmt);
2497 121636 : *removed_p = true;
2498 121636 : return retval;
2499 : }
2500 : }
2501 :
2502 : /* If this statement was not redundant, we may still be able to simplify
2503 : it, which may in turn allow other part of DOM or other passes to do
2504 : a better job. */
2505 54229705 : test_for_singularity (stmt, m_avail_exprs_stack);
2506 : }
2507 :
2508 : /* Record any additional equivalences created by this statement. */
2509 171180195 : if (is_gimple_assign (stmt))
2510 47527751 : record_equivalences_from_stmt (stmt, may_optimize_p, m_avail_exprs_stack);
2511 :
2512 : /* If STMT is a COND_EXPR or SWITCH_EXPR and it was modified, then we may
2513 : know where it goes. */
2514 342360390 : if (gimple_modified_p (stmt) || modified_p)
2515 : {
2516 3962065 : tree val = NULL;
2517 :
2518 3962065 : if (gimple_code (stmt) == GIMPLE_COND)
2519 434968 : val = fold_binary_loc (gimple_location (stmt),
2520 : gimple_cond_code (stmt), boolean_type_node,
2521 : gimple_cond_lhs (stmt),
2522 : gimple_cond_rhs (stmt));
2523 3527097 : else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt))
2524 2130 : val = gimple_switch_index (swtch_stmt);
2525 :
2526 437098 : if (val && TREE_CODE (val) == INTEGER_CST)
2527 : {
2528 63424 : retval = find_taken_edge (bb, val);
2529 63424 : if (retval)
2530 : {
2531 : /* Fix the condition to be either true or false. */
2532 63424 : if (gimple_code (stmt) == GIMPLE_COND)
2533 : {
2534 63408 : if (integer_zerop (val))
2535 32574 : gimple_cond_make_false (as_a <gcond *> (stmt));
2536 30834 : else if (integer_onep (val))
2537 30834 : gimple_cond_make_true (as_a <gcond *> (stmt));
2538 : else
2539 0 : gcc_unreachable ();
2540 :
2541 63408 : gimple_set_modified (stmt, true);
2542 : }
2543 :
2544 : /* Further simplifications may be possible. */
2545 63424 : cfg_altered = true;
2546 : }
2547 : }
2548 :
2549 3962065 : update_stmt_if_modified (stmt);
2550 :
2551 : /* If we simplified a statement in such a way as to be shown that it
2552 : cannot trap, update the eh information and the cfg to match. */
2553 3962065 : if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt))
2554 : {
2555 1506 : bitmap_set_bit (need_eh_cleanup, bb->index);
2556 1506 : if (dump_file && (dump_flags & TDF_DETAILS))
2557 0 : fprintf (dump_file, " Flagged to clear EH edges.\n");
2558 : }
2559 :
2560 3962065 : if (!was_noreturn
2561 3962065 : && is_gimple_call (stmt) && gimple_call_noreturn_p (stmt))
2562 3 : need_noreturn_fixup.safe_push (stmt);
2563 : }
2564 : return retval;
2565 : }
|
