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 "gimplify.h"
46 : #include "tree-cfgcleanup.h"
47 : #include "dbgcnt.h"
48 : #include "alloc-pool.h"
49 : #include "tree-vrp.h"
50 : #include "vr-values.h"
51 : #include "gimple-range.h"
52 : #include "gimple-range-path.h"
53 : #include "alias.h"
54 :
55 : /* This file implements optimizations on the dominator tree. */
56 :
57 : /* Structure for recording edge equivalences.
58 :
59 : Computing and storing the edge equivalences instead of creating
60 : them on-demand can save significant amounts of time, particularly
61 : for pathological cases involving switch statements.
62 :
63 : These structures live for a single iteration of the dominator
64 : optimizer in the edge's AUX field. At the end of an iteration we
65 : free each of these structures. */
66 : class edge_info
67 : {
68 : public:
69 : typedef std::pair <tree, tree> equiv_pair;
70 : edge_info (edge);
71 : ~edge_info ();
72 :
73 : /* Record a simple LHS = RHS equivalence. This may trigger
74 : calls to derive_equivalences. */
75 : void record_simple_equiv (tree, tree);
76 :
77 : /* If traversing this edge creates simple equivalences, we store
78 : them as LHS/RHS pairs within this vector. */
79 : vec<equiv_pair> simple_equivalences;
80 :
81 : /* Traversing an edge may also indicate one or more particular conditions
82 : are true or false. */
83 : vec<cond_equivalence> cond_equivalences;
84 :
85 : private:
86 : /* Derive equivalences by walking the use-def chains. */
87 : void derive_equivalences (tree, tree, int);
88 : };
89 :
90 : /* Track whether or not we have changed the control flow graph. */
91 : static bool cfg_altered;
92 :
93 : /* Bitmap of blocks that have had EH statements cleaned. We should
94 : remove their dead edges eventually. */
95 : static bitmap need_eh_cleanup;
96 : static vec<gimple *> need_noreturn_fixup;
97 :
98 : /* Statistics for dominator optimizations. */
99 : struct opt_stats_d
100 : {
101 : long num_stmts;
102 : long num_exprs_considered;
103 : long num_re;
104 : long num_const_prop;
105 : long num_copy_prop;
106 : };
107 :
108 : static struct opt_stats_d opt_stats;
109 :
110 : /* Local functions. */
111 : static void record_equality (tree, tree, class const_and_copies *);
112 : static void record_equivalences_from_phis (basic_block);
113 : static void record_equivalences_from_incoming_edge (basic_block,
114 : class const_and_copies *,
115 : class avail_exprs_stack *,
116 : bitmap blocks_on_stack);
117 : static void eliminate_redundant_computations (gimple_stmt_iterator *,
118 : class const_and_copies *,
119 : class avail_exprs_stack *);
120 : static void record_equivalences_from_stmt (gimple *, int,
121 : class avail_exprs_stack *);
122 : static void dump_dominator_optimization_stats (FILE *file,
123 : hash_table<expr_elt_hasher> *);
124 : static void record_temporary_equivalences (edge, class const_and_copies *,
125 : class avail_exprs_stack *, bitmap);
126 :
127 : /* Constructor for EDGE_INFO. An EDGE_INFO instance is always
128 : associated with an edge E. */
129 :
130 36392205 : edge_info::edge_info (edge e)
131 : {
132 : /* Free the old one associated with E, if it exists and
133 : associate our new object with E. */
134 36392205 : free_dom_edge_info (e);
135 36392205 : e->aux = this;
136 :
137 : /* And initialize the embedded vectors. */
138 36392205 : simple_equivalences = vNULL;
139 36392205 : cond_equivalences = vNULL;
140 36392205 : }
141 :
142 : /* Destructor just needs to release the vectors. */
143 :
144 36392205 : edge_info::~edge_info (void)
145 : {
146 36392205 : this->cond_equivalences.release ();
147 36392205 : this->simple_equivalences.release ();
148 36392205 : }
149 :
150 : /* NAME is known to have the value VALUE, which must be a constant.
151 :
152 : Walk through its use-def chain to see if there are other equivalences
153 : we might be able to derive.
154 :
155 : RECURSION_LIMIT controls how far back we recurse through the use-def
156 : chains. */
157 :
158 : void
159 13194271 : edge_info::derive_equivalences (tree name, tree value, int recursion_limit)
160 : {
161 15182901 : if (TREE_CODE (name) != SSA_NAME || TREE_CODE (value) != INTEGER_CST)
162 : return;
163 :
164 : /* This records the equivalence for the toplevel object. Do
165 : this before checking the recursion limit. */
166 15182621 : simple_equivalences.safe_push (equiv_pair (name, value));
167 :
168 : /* Limit how far up the use-def chains we are willing to walk. */
169 15182621 : if (recursion_limit == 0)
170 : return;
171 :
172 : /* We can walk up the use-def chains to potentially find more
173 : equivalences. */
174 15168189 : gimple *def_stmt = SSA_NAME_DEF_STMT (name);
175 15168189 : if (is_gimple_assign (def_stmt))
176 : {
177 9724666 : enum tree_code code = gimple_assign_rhs_code (def_stmt);
178 9724666 : switch (code)
179 : {
180 : /* If the result of an OR is zero, then its operands are, too. */
181 573497 : case BIT_IOR_EXPR:
182 573497 : if (integer_zerop (value))
183 : {
184 317271 : tree rhs1 = gimple_assign_rhs1 (def_stmt);
185 317271 : tree rhs2 = gimple_assign_rhs2 (def_stmt);
186 :
187 317271 : value = build_zero_cst (TREE_TYPE (rhs1));
188 317271 : derive_equivalences (rhs1, value, recursion_limit - 1);
189 317271 : value = build_zero_cst (TREE_TYPE (rhs2));
190 317271 : derive_equivalences (rhs2, value, recursion_limit - 1);
191 : }
192 : break;
193 :
194 : /* If the result of an AND is nonzero, then its operands are, too. */
195 1056752 : case BIT_AND_EXPR:
196 1056752 : if (!integer_zerop (value))
197 : {
198 446543 : tree rhs1 = gimple_assign_rhs1 (def_stmt);
199 446543 : tree rhs2 = gimple_assign_rhs2 (def_stmt);
200 :
201 : /* If either operand has a boolean range, then we
202 : know its value must be one, otherwise we just know it
203 : is nonzero. The former is clearly useful, I haven't
204 : seen cases where the latter is helpful yet. */
205 446543 : if (TREE_CODE (rhs1) == SSA_NAME)
206 : {
207 446543 : if (ssa_name_has_boolean_range (rhs1))
208 : {
209 261114 : value = build_one_cst (TREE_TYPE (rhs1));
210 261114 : derive_equivalences (rhs1, value, recursion_limit - 1);
211 : }
212 : }
213 446543 : if (TREE_CODE (rhs2) == SSA_NAME)
214 : {
215 263057 : if (ssa_name_has_boolean_range (rhs2))
216 : {
217 260827 : value = build_one_cst (TREE_TYPE (rhs2));
218 260827 : derive_equivalences (rhs2, value, recursion_limit - 1);
219 : }
220 : }
221 : }
222 : break;
223 :
224 : /* If LHS is an SSA_NAME and RHS is a constant integer and LHS was
225 : set via a widening type conversion, then we may be able to record
226 : additional equivalences. */
227 416330 : CASE_CONVERT:
228 416330 : {
229 416330 : tree rhs = gimple_assign_rhs1 (def_stmt);
230 416330 : tree rhs_type = TREE_TYPE (rhs);
231 416330 : if (INTEGRAL_TYPE_P (rhs_type)
232 414198 : && (TYPE_PRECISION (TREE_TYPE (name))
233 414198 : >= TYPE_PRECISION (rhs_type))
234 636390 : && int_fits_type_p (value, rhs_type))
235 209445 : derive_equivalences (rhs,
236 : fold_convert (rhs_type, value),
237 : recursion_limit - 1);
238 : break;
239 : }
240 :
241 : /* We can invert the operation of these codes trivially if
242 : one of the RHS operands is a constant to produce a known
243 : value for the other RHS operand. */
244 1027585 : case POINTER_PLUS_EXPR:
245 1027585 : case PLUS_EXPR:
246 1027585 : {
247 1027585 : tree rhs1 = gimple_assign_rhs1 (def_stmt);
248 1027585 : tree rhs2 = gimple_assign_rhs2 (def_stmt);
249 :
250 : /* If either argument is a constant, then we can compute
251 : a constant value for the nonconstant argument. */
252 1027585 : if (TREE_CODE (rhs1) == INTEGER_CST
253 0 : && TREE_CODE (rhs2) == SSA_NAME)
254 0 : derive_equivalences (rhs2,
255 0 : fold_binary (MINUS_EXPR, TREE_TYPE (rhs1),
256 : value, rhs1),
257 : recursion_limit - 1);
258 1027585 : else if (TREE_CODE (rhs2) == INTEGER_CST
259 976089 : && TREE_CODE (rhs1) == SSA_NAME)
260 976089 : derive_equivalences (rhs1,
261 976089 : fold_binary (MINUS_EXPR, TREE_TYPE (rhs1),
262 : value, rhs2),
263 : recursion_limit - 1);
264 : break;
265 : }
266 :
267 : /* If one of the operands is a constant, then we can compute
268 : the value of the other operand. If both operands are
269 : SSA_NAMEs, then they must be equal if the result is zero. */
270 82560 : case MINUS_EXPR:
271 82560 : {
272 82560 : tree rhs1 = gimple_assign_rhs1 (def_stmt);
273 82560 : tree rhs2 = gimple_assign_rhs2 (def_stmt);
274 :
275 : /* If either argument is a constant, then we can compute
276 : a constant value for the nonconstant argument. */
277 82560 : if (TREE_CODE (rhs1) == INTEGER_CST
278 898 : && TREE_CODE (rhs2) == SSA_NAME)
279 898 : derive_equivalences (rhs2,
280 898 : fold_binary (MINUS_EXPR, TREE_TYPE (rhs1),
281 : rhs1, value),
282 : recursion_limit - 1);
283 81662 : else if (TREE_CODE (rhs2) == INTEGER_CST
284 30012 : && TREE_CODE (rhs1) == SSA_NAME)
285 30012 : derive_equivalences (rhs1,
286 30012 : fold_binary (PLUS_EXPR, TREE_TYPE (rhs1),
287 : value, rhs2),
288 : recursion_limit - 1);
289 51650 : else if (integer_zerop (value))
290 : {
291 20946 : tree cond = build2 (EQ_EXPR, boolean_type_node,
292 : gimple_assign_rhs1 (def_stmt),
293 : gimple_assign_rhs2 (def_stmt));
294 20946 : tree inverted = invert_truthvalue (cond);
295 20946 : record_conditions (&this->cond_equivalences, cond, inverted);
296 : }
297 : break;
298 : }
299 :
300 670479 : case EQ_EXPR:
301 670479 : case NE_EXPR:
302 670479 : {
303 268731 : if ((code == EQ_EXPR && integer_onep (value))
304 796174 : || (code == NE_EXPR && integer_zerop (value)))
305 : {
306 394316 : tree rhs1 = gimple_assign_rhs1 (def_stmt);
307 394316 : tree rhs2 = gimple_assign_rhs2 (def_stmt);
308 :
309 : /* If either argument is a constant, then record the
310 : other argument as being the same as that constant.
311 :
312 : If neither operand is a constant, then we have a
313 : conditional name == name equivalence. */
314 394316 : if (TREE_CODE (rhs1) == INTEGER_CST)
315 0 : derive_equivalences (rhs2, rhs1, recursion_limit - 1);
316 394316 : else if (TREE_CODE (rhs2) == INTEGER_CST)
317 180542 : derive_equivalences (rhs1, rhs2, recursion_limit - 1);
318 : }
319 : else
320 : {
321 276163 : tree cond = build2 (code, boolean_type_node,
322 : gimple_assign_rhs1 (def_stmt),
323 276163 : gimple_assign_rhs2 (def_stmt));
324 276163 : tree inverted = invert_truthvalue (cond);
325 276163 : if (integer_zerop (value))
326 125695 : std::swap (cond, inverted);
327 276163 : record_conditions (&this->cond_equivalences, cond, inverted);
328 : }
329 : break;
330 : }
331 :
332 : /* For BIT_NOT and NEGATE, we can just apply the operation to the
333 : VALUE to get the new equivalence. It will always be a constant
334 : so we can recurse. */
335 13546 : case BIT_NOT_EXPR:
336 13546 : case NEGATE_EXPR:
337 13546 : {
338 13546 : tree rhs = gimple_assign_rhs1 (def_stmt);
339 13546 : tree res;
340 : /* If this is a NOT and the operand has a boolean range, then we
341 : know its value must be zero or one. We are not supposed to
342 : have a BIT_NOT_EXPR for boolean types with precision > 1 in
343 : the general case, see e.g. the handling of TRUTH_NOT_EXPR in
344 : the gimplifier, but it can be generated by match.pd out of
345 : a BIT_XOR_EXPR wrapped in a BIT_AND_EXPR. Now the handling
346 : of BIT_AND_EXPR above already forces a specific semantics for
347 : boolean types with precision > 1 so we must do the same here,
348 : otherwise we could change the semantics of TRUTH_NOT_EXPR for
349 : boolean types with precision > 1. */
350 13546 : if (code == BIT_NOT_EXPR
351 13348 : && TREE_CODE (rhs) == SSA_NAME
352 26894 : && ssa_name_has_boolean_range (rhs))
353 : {
354 12909 : if ((TREE_INT_CST_LOW (value) & 1) == 0)
355 6038 : res = build_one_cst (TREE_TYPE (rhs));
356 : else
357 6871 : res = build_zero_cst (TREE_TYPE (rhs));
358 : }
359 : else
360 637 : res = fold_build1 (code, TREE_TYPE (rhs), value);
361 13546 : derive_equivalences (rhs, res, recursion_limit - 1);
362 13546 : break;
363 : }
364 :
365 5883917 : default:
366 5883917 : {
367 5883917 : if (TREE_CODE_CLASS (code) == tcc_comparison)
368 : {
369 524598 : tree cond = build2 (code, boolean_type_node,
370 : gimple_assign_rhs1 (def_stmt),
371 524598 : gimple_assign_rhs2 (def_stmt));
372 524598 : tree inverted = invert_truthvalue (cond);
373 524598 : if (integer_zerop (value))
374 227725 : std::swap (cond, inverted);
375 524598 : record_conditions (&this->cond_equivalences, cond, inverted);
376 524598 : break;
377 : }
378 : break;
379 : }
380 : }
381 : }
382 : }
383 :
384 : void
385 15876391 : edge_info::record_simple_equiv (tree lhs, tree rhs)
386 : {
387 : /* If the RHS is a constant, then we may be able to derive
388 : further equivalences. Else just record the name = name
389 : equivalence. */
390 15876391 : if (TREE_CODE (rhs) == INTEGER_CST)
391 12615886 : derive_equivalences (lhs, rhs, 4);
392 : else
393 3260505 : simple_equivalences.safe_push (equiv_pair (lhs, rhs));
394 15876391 : }
395 :
396 : /* Free the edge_info data attached to E, if it exists and
397 : clear e->aux. */
398 :
399 : void
400 131023141 : free_dom_edge_info (edge e)
401 : {
402 131023141 : class edge_info *edge_info = (class edge_info *)e->aux;
403 :
404 131023141 : if (edge_info)
405 36392205 : delete edge_info;
406 131023141 : e->aux = NULL;
407 131023141 : }
408 :
409 : /* Free all EDGE_INFO structures associated with edges in the CFG.
410 : If a particular edge can be threaded, copy the redirection
411 : target from the EDGE_INFO structure into the edge's AUX field
412 : as required by code to update the CFG and SSA graph for
413 : jump threading. */
414 :
415 : static void
416 2083233 : free_all_edge_infos (void)
417 : {
418 2083233 : basic_block bb;
419 2083233 : edge_iterator ei;
420 2083233 : edge e;
421 :
422 23519818 : FOR_EACH_BB_FN (bb, cfun)
423 : {
424 51738800 : FOR_EACH_EDGE (e, ei, bb->preds)
425 30302215 : free_dom_edge_info (e);
426 : }
427 2083233 : }
428 :
429 : /* Return TRUE if BB has precisely two preds, one of which
430 : is a backedge from a forwarder block where the forwarder
431 : block is a direct successor of BB. Being a forwarder
432 : block, it has no side effects other than transfer of
433 : control. Otherwise return FALSE. */
434 :
435 : static bool
436 18200052 : single_block_loop_p (basic_block bb)
437 : {
438 : /* Two preds. */
439 18200052 : if (EDGE_COUNT (bb->preds) != 2)
440 : return false;
441 :
442 : /* One and only one of the edges must be marked with
443 : EDGE_DFS_BACK. */
444 5267317 : basic_block pred = NULL;
445 5267317 : unsigned int count = 0;
446 5267317 : if (EDGE_PRED (bb, 0)->flags & EDGE_DFS_BACK)
447 : {
448 1885340 : pred = EDGE_PRED (bb, 0)->src;
449 1885340 : count++;
450 : }
451 5267317 : if (EDGE_PRED (bb, 1)->flags & EDGE_DFS_BACK)
452 : {
453 402327 : pred = EDGE_PRED (bb, 1)->src;
454 402327 : count++;
455 : }
456 :
457 5267317 : if (count != 1)
458 : return false;
459 :
460 : /* Now examine PRED. It should have a single predecessor which
461 : is BB and a single successor that is also BB. */
462 2287667 : if (EDGE_COUNT (pred->preds) != 1
463 19370825 : || EDGE_COUNT (pred->succs) != 1
464 2207326 : || EDGE_PRED (pred, 0)->src != bb
465 3386057 : || EDGE_SUCC (pred, 0)->dest != bb)
466 : return false;
467 :
468 : /* This looks good from a CFG standpoint. Now look at the guts
469 : of PRED. Basically we want to verify there are no PHI nodes
470 : and no real statements. */
471 1098390 : if (! gimple_seq_empty_p (phi_nodes (pred)))
472 : return false;
473 :
474 1093627 : gimple_stmt_iterator gsi;
475 2211816 : for (gsi = gsi_last_bb (pred); !gsi_end_p (gsi); gsi_prev (&gsi))
476 : {
477 69355 : gimple *stmt = gsi_stmt (gsi);
478 :
479 69355 : switch (gimple_code (stmt))
480 : {
481 0 : case GIMPLE_LABEL:
482 0 : if (DECL_NONLOCAL (gimple_label_label (as_a <glabel *> (stmt))))
483 : return false;
484 : break;
485 :
486 : case GIMPLE_DEBUG:
487 : break;
488 :
489 : default:
490 : return false;
491 : }
492 : }
493 :
494 : return true;
495 : }
496 :
497 : /* We have finished optimizing BB, record any information implied by
498 : taking a specific outgoing edge from BB. */
499 :
500 : static void
501 44898211 : record_edge_info (basic_block bb)
502 : {
503 44898211 : gimple_stmt_iterator gsi = gsi_last_bb (bb);
504 44898211 : class edge_info *edge_info;
505 :
506 : /* Free all the outgoing edge info data associated with
507 : BB's outgoing edges. */
508 44898211 : edge e;
509 44898211 : edge_iterator ei;
510 107438029 : FOR_EACH_EDGE (e, ei, bb->succs)
511 62539818 : free_dom_edge_info (e);
512 :
513 44898211 : if (! gsi_end_p (gsi))
514 : {
515 38703225 : gimple *stmt = gsi_stmt (gsi);
516 38703225 : location_t loc = gimple_location (stmt);
517 :
518 38703225 : if (gimple_code (stmt) == GIMPLE_SWITCH)
519 : {
520 71401 : gswitch *switch_stmt = as_a <gswitch *> (stmt);
521 71401 : tree index = gimple_switch_index (switch_stmt);
522 :
523 71401 : if (TREE_CODE (index) == SSA_NAME)
524 : {
525 71386 : int i;
526 71386 : int n_labels = gimple_switch_num_labels (switch_stmt);
527 71386 : tree *info = XCNEWVEC (tree, last_basic_block_for_fn (cfun));
528 :
529 578269 : for (i = 0; i < n_labels; i++)
530 : {
531 506883 : tree label = gimple_switch_label (switch_stmt, i);
532 506883 : basic_block target_bb
533 506883 : = label_to_block (cfun, CASE_LABEL (label));
534 506883 : if (CASE_HIGH (label)
535 476129 : || !CASE_LOW (label)
536 911626 : || info[target_bb->index])
537 154148 : info[target_bb->index] = error_mark_node;
538 : else
539 352735 : info[target_bb->index] = label;
540 : }
541 :
542 518779 : FOR_EACH_EDGE (e, ei, bb->succs)
543 : {
544 447393 : basic_block target_bb = e->dest;
545 447393 : tree label = info[target_bb->index];
546 :
547 447393 : if (label != NULL && label != error_mark_node)
548 : {
549 647664 : tree x = fold_convert_loc (loc, TREE_TYPE (index),
550 323832 : CASE_LOW (label));
551 323832 : edge_info = new class edge_info (e);
552 323832 : edge_info->record_simple_equiv (index, x);
553 : }
554 : }
555 71386 : free (info);
556 : }
557 : }
558 :
559 : /* A COND_EXPR may create equivalences too. */
560 38703225 : if (gimple_code (stmt) == GIMPLE_COND)
561 : {
562 18200052 : edge true_edge;
563 18200052 : edge false_edge;
564 :
565 18200052 : tree op0 = gimple_cond_lhs (stmt);
566 18200052 : tree op1 = gimple_cond_rhs (stmt);
567 18200052 : enum tree_code code = gimple_cond_code (stmt);
568 :
569 18200052 : extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
570 :
571 : /* Special case comparing booleans against a constant as we
572 : know the value of OP0 on both arms of the branch. i.e., we
573 : can record an equivalence for OP0 rather than COND.
574 :
575 : However, don't do this if the constant isn't zero or one.
576 : Such conditionals will get optimized more thoroughly during
577 : the domwalk. */
578 18200052 : if ((code == EQ_EXPR || code == NE_EXPR)
579 13935708 : && TREE_CODE (op0) == SSA_NAME
580 13770050 : && ssa_name_has_boolean_range (op0)
581 2049165 : && is_gimple_min_invariant (op1)
582 20188209 : && (integer_zerop (op1) || integer_onep (op1)))
583 : {
584 1988157 : tree true_val = constant_boolean_node (true, TREE_TYPE (op0));
585 1988157 : tree false_val = constant_boolean_node (false, TREE_TYPE (op0));
586 :
587 1988157 : if (code == EQ_EXPR)
588 : {
589 81560 : edge_info = new class edge_info (true_edge);
590 119952 : edge_info->record_simple_equiv (op0,
591 81560 : (integer_zerop (op1)
592 : ? false_val : true_val));
593 81560 : edge_info = new class edge_info (false_edge);
594 119952 : edge_info->record_simple_equiv (op0,
595 81560 : (integer_zerop (op1)
596 : ? true_val : false_val));
597 : }
598 : else
599 : {
600 1906597 : edge_info = new class edge_info (true_edge);
601 1909829 : edge_info->record_simple_equiv (op0,
602 1906597 : (integer_zerop (op1)
603 : ? true_val : false_val));
604 1906597 : edge_info = new class edge_info (false_edge);
605 1909829 : edge_info->record_simple_equiv (op0,
606 1906597 : (integer_zerop (op1)
607 : ? false_val : true_val));
608 : }
609 : }
610 : /* This can show up in the IL as a result of copy propagation
611 : it will eventually be canonicalized, but we have to cope
612 : with this case within the pass. */
613 16211895 : else if (is_gimple_min_invariant (op0)
614 16211895 : && TREE_CODE (op1) == SSA_NAME)
615 : {
616 0 : tree cond = build2 (code, boolean_type_node, op0, op1);
617 0 : tree inverted = invert_truthvalue_loc (loc, cond);
618 0 : bool can_infer_simple_equiv
619 0 : = !(HONOR_SIGNED_ZEROS (op0) && real_maybe_zerop (op0))
620 0 : && !DECIMAL_FLOAT_MODE_P (element_mode (TREE_TYPE (op0)));
621 0 : class edge_info *edge_info;
622 :
623 0 : edge_info = new class edge_info (true_edge);
624 0 : record_conditions (&edge_info->cond_equivalences, cond, inverted);
625 :
626 0 : if (can_infer_simple_equiv && code == EQ_EXPR)
627 0 : edge_info->record_simple_equiv (op1, op0);
628 :
629 0 : edge_info = new class edge_info (false_edge);
630 0 : record_conditions (&edge_info->cond_equivalences, inverted, cond);
631 :
632 0 : if (can_infer_simple_equiv && TREE_CODE (inverted) == EQ_EXPR)
633 0 : edge_info->record_simple_equiv (op1, op0);
634 : }
635 :
636 16211895 : else if (TREE_CODE (op0) == SSA_NAME
637 16211895 : && (TREE_CODE (op1) == SSA_NAME
638 11898816 : || is_gimple_min_invariant (op1)))
639 : {
640 16045732 : tree cond = build2 (code, boolean_type_node, op0, op1);
641 16045732 : tree inverted = invert_truthvalue_loc (loc, cond);
642 16045732 : bool can_infer_simple_equiv
643 16738366 : = !(HONOR_SIGNED_ZEROS (op1) && real_maybe_zerop (op1))
644 16442568 : && !DECIMAL_FLOAT_MODE_P (element_mode (TREE_TYPE (op1)));
645 16045732 : class edge_info *edge_info;
646 :
647 16045732 : edge_info = new class edge_info (true_edge);
648 16045732 : record_conditions (&edge_info->cond_equivalences, cond, inverted);
649 :
650 16045732 : if (can_infer_simple_equiv && code == EQ_EXPR)
651 5431907 : edge_info->record_simple_equiv (op0, op1);
652 :
653 16045732 : edge_info = new class edge_info (false_edge);
654 16045732 : record_conditions (&edge_info->cond_equivalences, inverted, cond);
655 :
656 16045732 : if (can_infer_simple_equiv && TREE_CODE (inverted) == EQ_EXPR)
657 6143165 : edge_info->record_simple_equiv (op0, op1);
658 : }
659 :
660 : /* If this block is a single block loop, then we may be able to
661 : record some equivalences on the loop's exit edge. */
662 18200052 : if (single_block_loop_p (bb))
663 : {
664 : /* We know it's a single block loop. Now look at the loop
665 : exit condition. What we're looking for is whether or not
666 : the exit condition is loop invariant which we can detect
667 : by checking if all the SSA_NAMEs referenced are defined
668 : outside the loop. */
669 1036553 : if ((TREE_CODE (op0) != SSA_NAME
670 1035897 : || gimple_bb (SSA_NAME_DEF_STMT (op0)) != bb)
671 1202659 : && (TREE_CODE (op1) != SSA_NAME
672 164537 : || gimple_bb (SSA_NAME_DEF_STMT (op1)) != bb))
673 : {
674 : /* At this point we know the exit condition is loop
675 : invariant. The only way to get out of the loop is
676 : if it never traverses the backedge to begin with. This
677 : implies that any PHI nodes create equivalances that we
678 : can attach to the loop exit edge. */
679 2350 : bool alternative
680 2350 : = (EDGE_PRED (bb, 0)->flags & EDGE_DFS_BACK) ? 1 : 0;
681 :
682 2350 : gphi_iterator gsi;
683 2350 : for (gsi = gsi_start_phis (bb);
684 3828 : !gsi_end_p (gsi);
685 1478 : gsi_next (&gsi))
686 : {
687 : /* Now get the EDGE_INFO class so we can append
688 : it to our list. We want the successor edge
689 : where the destination is not the source of
690 : an incoming edge. */
691 1478 : gphi *phi = gsi.phi ();
692 1478 : tree src = PHI_ARG_DEF (phi, alternative);
693 1478 : tree dst = PHI_RESULT (phi);
694 :
695 : /* If the other alternative is the same as the result,
696 : then this is a degenerate and can be ignored. */
697 1478 : if (dst == PHI_ARG_DEF (phi, !alternative))
698 305 : continue;
699 :
700 1173 : if (EDGE_SUCC (bb, 0)->dest
701 1173 : != EDGE_PRED (bb, !alternative)->src)
702 289 : edge_info = (class edge_info *)EDGE_SUCC (bb, 0)->aux;
703 : else
704 884 : edge_info = (class edge_info *)EDGE_SUCC (bb, 1)->aux;
705 :
706 : /* Note that since this processing is done independently
707 : of other edge equivalency processing, we may not
708 : have an EDGE_INFO structure set up yet. */
709 1173 : if (edge_info == NULL)
710 595 : edge_info = new class edge_info (false_edge);
711 1173 : edge_info->record_simple_equiv (dst, src);
712 : }
713 : }
714 : }
715 : }
716 : }
717 44898211 : }
718 :
719 : class dom_jt_state : public jt_state
720 : {
721 : public:
722 2083233 : dom_jt_state (const_and_copies *copies, avail_exprs_stack *avails)
723 2083233 : : m_copies (copies), m_avails (avails)
724 : {
725 2083233 : bitmap_tree_view (m_blocks_on_stack);
726 2083233 : }
727 16849372 : void push (edge e) override
728 : {
729 16849372 : m_copies->push_marker ();
730 16849372 : m_avails->push_marker ();
731 16849372 : jt_state::push (e);
732 16849372 : }
733 16849372 : void pop () override
734 : {
735 16849372 : m_copies->pop_to_marker ();
736 16849372 : m_avails->pop_to_marker ();
737 16849372 : jt_state::pop ();
738 16849372 : }
739 15604949 : void register_equivs_edge (edge e) override
740 : {
741 15604949 : record_temporary_equivalences (e, m_copies, m_avails, m_blocks_on_stack);
742 15604949 : }
743 : void register_equiv (tree dest, tree src, bool update) override;
744 70384878 : bitmap get_blocks_on_stack () { return m_blocks_on_stack; }
745 : private:
746 : const_and_copies *m_copies;
747 : avail_exprs_stack *m_avails;
748 : /* Set of blocks on the stack, to be used for medium-fast
749 : dominance queries in back_propagate_equivalences. */
750 : auto_bitmap m_blocks_on_stack;
751 : };
752 :
753 : void
754 21417419 : dom_jt_state::register_equiv (tree dest, tree src, bool)
755 : {
756 21417419 : m_copies->record_const_or_copy (dest, src);
757 21417419 : }
758 :
759 2083233 : class dom_jt_simplifier : public hybrid_jt_simplifier
760 : {
761 : public:
762 2083233 : dom_jt_simplifier (avail_exprs_stack *avails, gimple_ranger *ranger,
763 : path_range_query *query)
764 4166466 : : hybrid_jt_simplifier (ranger, query), m_avails (avails) { }
765 :
766 : private:
767 : tree simplify (gimple *, gimple *, basic_block, jt_state *) override;
768 : avail_exprs_stack *m_avails;
769 : };
770 :
771 : tree
772 31236696 : dom_jt_simplifier::simplify (gimple *stmt, gimple *within_stmt,
773 : basic_block bb, jt_state *state)
774 : {
775 : /* First see if the conditional is in the hash table. */
776 31236696 : tree cached_lhs = m_avails->lookup_avail_expr (stmt, false, true);
777 31236696 : if (cached_lhs)
778 : return cached_lhs;
779 :
780 : /* Otherwise call the ranger if possible. */
781 30438216 : if (state)
782 8681083 : return hybrid_jt_simplifier::simplify (stmt, within_stmt, bb, state);
783 :
784 : return NULL;
785 : }
786 :
787 4166466 : class dom_opt_dom_walker : public dom_walker
788 : {
789 : public:
790 2083233 : dom_opt_dom_walker (cdi_direction direction,
791 : jump_threader *threader,
792 : dom_jt_state *state,
793 : gimple_ranger *ranger,
794 : const_and_copies *const_and_copies,
795 : avail_exprs_stack *avail_exprs_stack)
796 2083233 : : dom_walker (direction, REACHABLE_BLOCKS)
797 : {
798 2083233 : m_ranger = ranger;
799 2083233 : m_state = state;
800 2083233 : m_dummy_cond = gimple_build_cond (NE_EXPR, integer_zero_node,
801 : integer_zero_node, NULL, NULL);
802 2083233 : m_const_and_copies = const_and_copies;
803 2083233 : m_avail_exprs_stack = avail_exprs_stack;
804 2083233 : m_threader = threader;
805 2083233 : }
806 :
807 : edge before_dom_children (basic_block) final override;
808 : void after_dom_children (basic_block) final override;
809 :
810 : private:
811 :
812 : /* Unwindable equivalences, both const/copy and expression varieties. */
813 : class const_and_copies *m_const_and_copies;
814 : class avail_exprs_stack *m_avail_exprs_stack;
815 :
816 : /* Dummy condition to avoid creating lots of throw away statements. */
817 : gcond *m_dummy_cond;
818 :
819 : /* Optimize a single statement within a basic block using the
820 : various tables mantained by DOM. Returns the taken edge if
821 : the statement is a conditional with a statically determined
822 : value. */
823 : edge optimize_stmt (basic_block, gimple_stmt_iterator *, bool *);
824 :
825 : void set_global_ranges_from_unreachable_edges (basic_block);
826 :
827 : void test_for_singularity (gimple *, avail_exprs_stack *);
828 : edge fold_cond (gcond *cond);
829 :
830 : jump_threader *m_threader;
831 : gimple_ranger *m_ranger;
832 : dom_jt_state *m_state;
833 : };
834 :
835 : /* Jump threading, redundancy elimination and const/copy propagation.
836 :
837 : This pass may expose new symbols that need to be renamed into SSA. For
838 : every new symbol exposed, its corresponding bit will be set in
839 : VARS_TO_RENAME. */
840 :
841 : namespace {
842 :
843 : const pass_data pass_data_dominator =
844 : {
845 : GIMPLE_PASS, /* type */
846 : "dom", /* name */
847 : OPTGROUP_NONE, /* optinfo_flags */
848 : TV_TREE_SSA_DOMINATOR_OPTS, /* tv_id */
849 : ( PROP_cfg | PROP_ssa ), /* properties_required */
850 : 0, /* properties_provided */
851 : 0, /* properties_destroyed */
852 : 0, /* todo_flags_start */
853 : ( TODO_cleanup_cfg | TODO_update_ssa ), /* todo_flags_finish */
854 : };
855 :
856 : class pass_dominator : public gimple_opt_pass
857 : {
858 : public:
859 857166 : pass_dominator (gcc::context *ctxt)
860 857166 : : gimple_opt_pass (pass_data_dominator, ctxt),
861 1714332 : may_peel_loop_headers_p (false)
862 : {}
863 :
864 : /* opt_pass methods: */
865 571444 : opt_pass * clone () final override { return new pass_dominator (m_ctxt); }
866 857166 : void set_pass_param (unsigned int n, bool param) final override
867 : {
868 857166 : gcc_assert (n == 0);
869 857166 : may_peel_loop_headers_p = param;
870 857166 : }
871 2084006 : bool gate (function *) final override { return flag_tree_dom != 0; }
872 : unsigned int execute (function *) final override;
873 :
874 : private:
875 : /* This flag is used to prevent loops from being peeled repeatedly in jump
876 : threading; it will be removed once we preserve loop structures throughout
877 : the compilation -- we will be able to mark the affected loops directly in
878 : jump threading, and avoid peeling them next time. */
879 : bool may_peel_loop_headers_p;
880 : }; // class pass_dominator
881 :
882 : unsigned int
883 2083233 : pass_dominator::execute (function *fun)
884 : {
885 2083233 : memset (&opt_stats, 0, sizeof (opt_stats));
886 :
887 : /* Create our hash tables. */
888 2083233 : hash_table<expr_elt_hasher> *avail_exprs
889 2083233 : = new hash_table<expr_elt_hasher> (1024);
890 2083233 : class avail_exprs_stack *avail_exprs_stack
891 2083233 : = new class avail_exprs_stack (avail_exprs);
892 2083233 : class const_and_copies *const_and_copies = new class const_and_copies ();
893 2083233 : need_eh_cleanup = BITMAP_ALLOC (NULL);
894 2083233 : need_noreturn_fixup.create (0);
895 :
896 2083233 : calculate_dominance_info (CDI_DOMINATORS);
897 2083233 : cfg_altered = false;
898 :
899 : /* We need to know loop structures in order to avoid destroying them
900 : in jump threading. Note that we still can e.g. thread through loop
901 : headers to an exit edge, or through loop header to the loop body, assuming
902 : that we update the loop info.
903 :
904 : TODO: We don't need to set LOOPS_HAVE_PREHEADERS generally, but due
905 : to several overly conservative bail-outs in jump threading, case
906 : gcc.dg/tree-ssa/pr21417.c can't be threaded if loop preheader is
907 : missing. We should improve jump threading in future then
908 : LOOPS_HAVE_PREHEADERS won't be needed here. */
909 2083233 : loop_optimizer_init (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES
910 : | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS);
911 :
912 : /* We need accurate information regarding back edges in the CFG
913 : for jump threading; this may include back edges that are not part of
914 : a single loop. */
915 2083233 : mark_dfs_back_edges ();
916 :
917 : /* We want to create the edge info structures before the dominator walk
918 : so that they'll be in place for the jump threader, particularly when
919 : threading through a join block.
920 :
921 : The conditions will be lazily updated with global equivalences as
922 : we reach them during the dominator walk. */
923 2083233 : basic_block bb;
924 23519818 : FOR_EACH_BB_FN (bb, fun)
925 21436585 : record_edge_info (bb);
926 :
927 : /* Recursively walk the dominator tree optimizing statements. */
928 2083233 : gimple_ranger *ranger = enable_ranger (fun);
929 2083233 : path_range_query path_query (*ranger);
930 2083233 : dom_jt_simplifier simplifier (avail_exprs_stack, ranger, &path_query);
931 2083233 : dom_jt_state state (const_and_copies, avail_exprs_stack);
932 2083233 : jump_threader threader (&simplifier, &state);
933 2083233 : dom_opt_dom_walker walker (CDI_DOMINATORS,
934 : &threader,
935 : &state,
936 : ranger,
937 : const_and_copies,
938 2083233 : avail_exprs_stack);
939 2083233 : walker.walk (fun->cfg->x_entry_block_ptr);
940 :
941 2083233 : ranger->export_global_ranges ();
942 2083233 : disable_ranger (fun);
943 :
944 : /* Look for blocks where we cleared EDGE_EXECUTABLE on an outgoing
945 : edge. When found, remove jump threads which contain any outgoing
946 : edge from the affected block. */
947 2083233 : if (cfg_altered)
948 : {
949 4335115 : FOR_EACH_BB_FN (bb, fun)
950 : {
951 4277268 : edge_iterator ei;
952 4277268 : edge e;
953 :
954 : /* First see if there are any edges without EDGE_EXECUTABLE
955 : set. */
956 4277268 : bool found = false;
957 10290206 : FOR_EACH_EDGE (e, ei, bb->succs)
958 : {
959 6206471 : if ((e->flags & EDGE_EXECUTABLE) == 0)
960 : {
961 : found = true;
962 : break;
963 : }
964 : }
965 :
966 : /* If there were any such edges found, then remove jump threads
967 : containing any edge leaving BB. */
968 4277268 : if (found)
969 563920 : FOR_EACH_EDGE (e, ei, bb->succs)
970 370387 : threader.remove_jump_threads_including (e);
971 : }
972 : }
973 :
974 2083233 : {
975 2083233 : gimple_stmt_iterator gsi;
976 2083233 : basic_block bb;
977 23519818 : FOR_EACH_BB_FN (bb, fun)
978 : {
979 213388398 : for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
980 170515228 : update_stmt_if_modified (gsi_stmt (gsi));
981 : }
982 : }
983 :
984 : /* If we exposed any new variables, go ahead and put them into
985 : SSA form now, before we handle jump threading. This simplifies
986 : interactions between rewriting of _DECL nodes into SSA form
987 : and rewriting SSA_NAME nodes into SSA form after block
988 : duplication and CFG manipulation. */
989 2083233 : update_ssa (TODO_update_ssa);
990 :
991 2083233 : free_all_edge_infos ();
992 :
993 : /* Thread jumps, creating duplicate blocks as needed. */
994 2083233 : cfg_altered |= threader.thread_through_all_blocks (may_peel_loop_headers_p);
995 :
996 2083233 : if (cfg_altered)
997 135113 : free_dominance_info (CDI_DOMINATORS);
998 :
999 : /* Removal of statements may make some EH edges dead. Purge
1000 : such edges from the CFG as needed. */
1001 2083233 : if (!bitmap_empty_p (need_eh_cleanup))
1002 : {
1003 621 : unsigned i;
1004 621 : bitmap_iterator bi;
1005 :
1006 : /* Jump threading may have created forwarder blocks from blocks
1007 : needing EH cleanup; the new successor of these blocks, which
1008 : has inherited from the original block, needs the cleanup.
1009 : Don't clear bits in the bitmap, as that can break the bitmap
1010 : iterator. */
1011 1992 : EXECUTE_IF_SET_IN_BITMAP (need_eh_cleanup, 0, i, bi)
1012 : {
1013 1371 : basic_block bb = BASIC_BLOCK_FOR_FN (fun, i);
1014 1371 : if (bb == NULL)
1015 0 : continue;
1016 2813 : while (single_succ_p (bb)
1017 1484 : && (single_succ_edge (bb)->flags
1018 122 : & (EDGE_EH|EDGE_DFS_BACK)) == 0)
1019 113 : bb = single_succ (bb);
1020 1371 : if (bb == EXIT_BLOCK_PTR_FOR_FN (fun))
1021 42 : continue;
1022 1329 : if ((unsigned) bb->index != i)
1023 55 : bitmap_set_bit (need_eh_cleanup, bb->index);
1024 : }
1025 :
1026 621 : gimple_purge_all_dead_eh_edges (need_eh_cleanup);
1027 621 : bitmap_clear (need_eh_cleanup);
1028 : }
1029 :
1030 : /* Fixup stmts that became noreturn calls. This may require splitting
1031 : blocks and thus isn't possible during the dominator walk or before
1032 : jump threading finished. Do this in reverse order so we don't
1033 : inadvertedly remove a stmt we want to fixup by visiting a dominating
1034 : now noreturn call first. */
1035 2083236 : while (!need_noreturn_fixup.is_empty ())
1036 : {
1037 3 : gimple *stmt = need_noreturn_fixup.pop ();
1038 3 : if (dump_file && dump_flags & TDF_DETAILS)
1039 : {
1040 0 : fprintf (dump_file, "Fixing up noreturn call ");
1041 0 : print_gimple_stmt (dump_file, stmt, 0);
1042 0 : fprintf (dump_file, "\n");
1043 : }
1044 3 : fixup_noreturn_call (stmt);
1045 : }
1046 :
1047 2083233 : statistics_counter_event (fun, "Redundant expressions eliminated",
1048 2083233 : opt_stats.num_re);
1049 2083233 : statistics_counter_event (fun, "Constants propagated",
1050 2083233 : opt_stats.num_const_prop);
1051 2083233 : statistics_counter_event (fun, "Copies propagated",
1052 2083233 : opt_stats.num_copy_prop);
1053 :
1054 : /* Debugging dumps. */
1055 2083233 : if (dump_file && (dump_flags & TDF_STATS))
1056 35 : dump_dominator_optimization_stats (dump_file, avail_exprs);
1057 :
1058 2083233 : loop_optimizer_finalize ();
1059 :
1060 : /* Delete our main hashtable. */
1061 2083233 : delete avail_exprs;
1062 2083233 : avail_exprs = NULL;
1063 :
1064 : /* Free asserted bitmaps and stacks. */
1065 2083233 : BITMAP_FREE (need_eh_cleanup);
1066 2083233 : need_noreturn_fixup.release ();
1067 2083233 : delete avail_exprs_stack;
1068 2083233 : delete const_and_copies;
1069 :
1070 2083233 : return 0;
1071 2083233 : }
1072 :
1073 : } // anon namespace
1074 :
1075 : gimple_opt_pass *
1076 285722 : make_pass_dominator (gcc::context *ctxt)
1077 : {
1078 285722 : return new pass_dominator (ctxt);
1079 : }
1080 :
1081 : /* Valueize hook for gimple_fold_stmt_to_constant_1. */
1082 :
1083 : static tree
1084 34068365 : dom_valueize (tree t)
1085 : {
1086 34068365 : if (TREE_CODE (t) == SSA_NAME)
1087 : {
1088 24407073 : tree tem = SSA_NAME_VALUE (t);
1089 19338718 : if (tem)
1090 2955615 : return tem;
1091 : }
1092 : return t;
1093 : }
1094 :
1095 : /* We have just found an equivalence for LHS on an edge E.
1096 : Look backwards to other uses of LHS and see if we can derive
1097 : additional equivalences that are valid on edge E. */
1098 : static void
1099 12077834 : back_propagate_equivalences (tree lhs, edge e,
1100 : class const_and_copies *const_and_copies,
1101 : bitmap domby)
1102 : {
1103 12077834 : use_operand_p use_p;
1104 12077834 : imm_use_iterator iter;
1105 12077834 : basic_block dest = e->dest;
1106 12077834 : bool domok = (dom_info_state (CDI_DOMINATORS) == DOM_OK);
1107 :
1108 : /* Iterate over the uses of LHS to see if any dominate E->dest.
1109 : If so, they may create useful equivalences too.
1110 :
1111 : ??? If the code gets re-organized to a worklist to catch more
1112 : indirect opportunities and it is made to handle PHIs then this
1113 : should only consider use_stmts in basic-blocks we have already visited. */
1114 63984847 : FOR_EACH_IMM_USE_FAST (use_p, iter, lhs)
1115 : {
1116 39829179 : gimple *use_stmt = USE_STMT (use_p);
1117 :
1118 : /* Often the use is in DEST, which we trivially know we can't use.
1119 : This is cheaper than the dominator set tests below. */
1120 39829179 : if (dest == gimple_bb (use_stmt))
1121 545278 : continue;
1122 :
1123 : /* Filter out statements that can never produce a useful
1124 : equivalence. */
1125 39283901 : tree lhs2 = gimple_get_lhs (use_stmt);
1126 39283901 : if (!lhs2 || TREE_CODE (lhs2) != SSA_NAME)
1127 29131361 : continue;
1128 :
1129 10152540 : if (domok)
1130 : {
1131 5818480 : if (!dominated_by_p (CDI_DOMINATORS, dest, gimple_bb (use_stmt)))
1132 2988321 : continue;
1133 : }
1134 : else
1135 : {
1136 : /* We can use the set of BBs on the stack from a domwalk
1137 : for a medium fast way to query dominance. Profiling
1138 : has shown non-fast query dominance tests here can be fairly
1139 : expensive. */
1140 : /* This tests if USE_STMT does not dominate DEST. */
1141 4334060 : if (!bitmap_bit_p (domby, gimple_bb (use_stmt)->index))
1142 3248008 : continue;
1143 : }
1144 :
1145 : /* At this point USE_STMT dominates DEST and may result in a
1146 : useful equivalence. Try to simplify its RHS to a constant
1147 : or SSA_NAME. */
1148 3916211 : tree res = gimple_fold_stmt_to_constant_1 (use_stmt, dom_valueize,
1149 : no_follow_ssa_edges);
1150 3916211 : if (res && (TREE_CODE (res) == SSA_NAME || is_gimple_min_invariant (res)))
1151 2284201 : record_equality (lhs2, res, const_and_copies);
1152 12077834 : }
1153 12077834 : }
1154 :
1155 : /* Record into CONST_AND_COPIES and AVAIL_EXPRS_STACK any equivalences implied
1156 : by traversing edge E (which are cached in E->aux).
1157 :
1158 : Callers are responsible for managing the unwinding markers. */
1159 : static void
1160 33023638 : record_temporary_equivalences (edge e,
1161 : class const_and_copies *const_and_copies,
1162 : class avail_exprs_stack *avail_exprs_stack,
1163 : bitmap blocks_on_stack)
1164 : {
1165 33023638 : int i;
1166 33023638 : class edge_info *edge_info = (class edge_info *) e->aux;
1167 :
1168 : /* If we have info associated with this edge, record it into
1169 : our equivalence tables. */
1170 33023638 : if (edge_info)
1171 : {
1172 : cond_equivalence *eq;
1173 : /* If we have 0 = COND or 1 = COND equivalences, record them
1174 : into our expression hash tables. */
1175 91610431 : for (i = 0; edge_info->cond_equivalences.iterate (i, &eq); ++i)
1176 67724683 : avail_exprs_stack->record_cond (eq);
1177 :
1178 : edge_info::equiv_pair *seq;
1179 35963582 : for (i = 0; edge_info->simple_equivalences.iterate (i, &seq); ++i)
1180 : {
1181 12077834 : tree lhs = seq->first;
1182 12077834 : if (!lhs || TREE_CODE (lhs) != SSA_NAME)
1183 0 : continue;
1184 :
1185 : /* Record the simple NAME = VALUE equivalence. */
1186 12077834 : tree rhs = seq->second;
1187 :
1188 : /* If this is a SSA_NAME = SSA_NAME equivalence and one operand is
1189 : cheaper to compute than the other, then set up the equivalence
1190 : such that we replace the expensive one with the cheap one.
1191 :
1192 : If they are the same cost to compute, then do not record
1193 : anything. */
1194 12077834 : if (TREE_CODE (lhs) == SSA_NAME && TREE_CODE (rhs) == SSA_NAME)
1195 : {
1196 1730037 : gimple *rhs_def = SSA_NAME_DEF_STMT (rhs);
1197 1730037 : int rhs_cost = estimate_num_insns (rhs_def, &eni_size_weights);
1198 :
1199 1730037 : gimple *lhs_def = SSA_NAME_DEF_STMT (lhs);
1200 1730037 : int lhs_cost = estimate_num_insns (lhs_def, &eni_size_weights);
1201 :
1202 1730037 : if (rhs_cost > lhs_cost)
1203 183520 : record_equality (rhs, lhs, const_and_copies);
1204 1546517 : else if (rhs_cost < lhs_cost)
1205 462827 : record_equality (lhs, rhs, const_and_copies);
1206 : }
1207 : else
1208 10347797 : record_equality (lhs, rhs, const_and_copies);
1209 :
1210 :
1211 : /* Any equivalence found for LHS may result in additional
1212 : equivalences for other uses of LHS that we have already
1213 : processed. */
1214 12077834 : back_propagate_equivalences (lhs, e, const_and_copies,
1215 : blocks_on_stack);
1216 : }
1217 : }
1218 33023638 : }
1219 :
1220 : /* PHI nodes can create equivalences too.
1221 :
1222 : Ignoring any alternatives which are the same as the result, if
1223 : all the alternatives are equal, then the PHI node creates an
1224 : equivalence. */
1225 :
1226 : static void
1227 23461626 : record_equivalences_from_phis (basic_block bb)
1228 : {
1229 23461626 : gphi_iterator gsi;
1230 :
1231 32727926 : for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
1232 : {
1233 9266300 : gphi *phi = gsi.phi ();
1234 :
1235 : /* We might eliminate the PHI, so advance GSI now. */
1236 9266300 : gsi_next (&gsi);
1237 :
1238 9266300 : tree lhs = gimple_phi_result (phi);
1239 9266300 : tree rhs = NULL;
1240 9266300 : size_t i;
1241 :
1242 16704137 : for (i = 0; i < gimple_phi_num_args (phi); i++)
1243 : {
1244 15744699 : tree t = gimple_phi_arg_def (phi, i);
1245 :
1246 : /* Ignore alternatives which are the same as our LHS. Since
1247 : LHS is a PHI_RESULT, it is known to be a SSA_NAME, so we
1248 : can simply compare pointers. */
1249 15744699 : if (lhs == t)
1250 25786 : continue;
1251 :
1252 : /* If the associated edge is not marked as executable, then it
1253 : can be ignored. */
1254 15718913 : if ((gimple_phi_arg_edge (phi, i)->flags & EDGE_EXECUTABLE) == 0)
1255 115443 : continue;
1256 :
1257 15603470 : t = dom_valueize (t);
1258 :
1259 : /* If T is an SSA_NAME and its associated edge is a backedge,
1260 : then quit as we cannot utilize this equivalence. */
1261 15603470 : if (TREE_CODE (t) == SSA_NAME
1262 15603470 : && (gimple_phi_arg_edge (phi, i)->flags & EDGE_DFS_BACK))
1263 : break;
1264 :
1265 : /* If we have not processed an alternative yet, then set
1266 : RHS to this alternative. */
1267 12592747 : if (rhs == NULL)
1268 : rhs = t;
1269 : /* If we have processed an alternative (stored in RHS), then
1270 : see if it is equal to this one. If it isn't, then stop
1271 : the search. */
1272 5820094 : else if (! operand_equal_for_phi_arg_p (rhs, t))
1273 : break;
1274 : }
1275 :
1276 : /* If we had no interesting alternatives, then all the RHS alternatives
1277 : must have been the same as LHS. */
1278 9266300 : if (!rhs)
1279 2493647 : rhs = lhs;
1280 :
1281 : /* If we managed to iterate through each PHI alternative without
1282 : breaking out of the loop, then we have a PHI which may create
1283 : a useful equivalence. We do not need to record unwind data for
1284 : this, since this is a true assignment and not an equivalence
1285 : inferred from a comparison. All uses of this ssa name are dominated
1286 : by this assignment, so unwinding just costs time and space. */
1287 9266300 : if (i == gimple_phi_num_args (phi))
1288 : {
1289 959438 : if (may_propagate_copy (lhs, rhs))
1290 519028 : set_ssa_name_value (lhs, rhs);
1291 880820 : else if (virtual_operand_p (lhs))
1292 : {
1293 440134 : gimple *use_stmt;
1294 440134 : imm_use_iterator iter;
1295 440134 : use_operand_p use_p;
1296 : /* For virtual operands we have to propagate into all uses as
1297 : otherwise we will create overlapping life-ranges. */
1298 1735208 : FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
1299 2614364 : FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
1300 879712 : SET_USE (use_p, rhs);
1301 440134 : if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
1302 71 : SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs) = 1;
1303 440134 : gimple_stmt_iterator tmp_gsi = gsi_for_stmt (phi);
1304 440134 : remove_phi_node (&tmp_gsi, true);
1305 : }
1306 : }
1307 : }
1308 23461626 : }
1309 :
1310 : /* Return true if all uses of NAME are dominated by STMT or feed STMT
1311 : via a chain of single immediate uses. */
1312 :
1313 : static bool
1314 407708 : all_uses_feed_or_dominated_by_stmt (tree name, gimple *stmt)
1315 : {
1316 407708 : use_operand_p use_p, use2_p;
1317 407708 : imm_use_iterator iter;
1318 407708 : basic_block stmt_bb = gimple_bb (stmt);
1319 :
1320 2049729 : FOR_EACH_IMM_USE_FAST (use_p, iter, name)
1321 : {
1322 1449214 : gimple *use_stmt = USE_STMT (use_p), *use_stmt2;
1323 2674414 : if (use_stmt == stmt
1324 1312732 : || is_gimple_debug (use_stmt)
1325 2174462 : || (gimple_bb (use_stmt) != stmt_bb
1326 571713 : && dominated_by_p (CDI_DOMINATORS,
1327 571713 : gimple_bb (use_stmt), stmt_bb)))
1328 1225200 : continue;
1329 : while (use_stmt != stmt
1330 429914 : && is_gimple_assign (use_stmt)
1331 379687 : && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME
1332 805847 : && single_imm_use (gimple_assign_lhs (use_stmt),
1333 : &use2_p, &use_stmt2))
1334 215013 : use_stmt = use_stmt2;
1335 224014 : if (use_stmt != stmt)
1336 214901 : return false;
1337 214901 : }
1338 192807 : return true;
1339 : }
1340 :
1341 : /* Handle
1342 : _4 = x_3 & 31;
1343 : if (_4 != 0)
1344 : goto <bb 6>;
1345 : else
1346 : goto <bb 7>;
1347 : <bb 6>:
1348 : __builtin_unreachable ();
1349 : <bb 7>:
1350 :
1351 : If x_3 has no other immediate uses (checked by caller), var is the
1352 : x_3 var, we can clear low 5 bits from the non-zero bitmask. */
1353 :
1354 : static void
1355 173458 : maybe_set_nonzero_bits (edge e, tree var)
1356 : {
1357 173458 : basic_block cond_bb = e->src;
1358 346916 : gcond *cond = safe_dyn_cast <gcond *> (*gsi_last_bb (cond_bb));
1359 173458 : tree cst;
1360 :
1361 173458 : if (cond == NULL
1362 173458 : || gimple_cond_code (cond) != ((e->flags & EDGE_TRUE_VALUE)
1363 173458 : ? EQ_EXPR : NE_EXPR)
1364 51260 : || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME
1365 1656 : || !integer_zerop (gimple_cond_rhs (cond)))
1366 172002 : return;
1367 :
1368 1456 : gimple *stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond));
1369 1456 : if (!is_gimple_assign (stmt)
1370 1434 : || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR
1371 1473 : || TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST)
1372 : return;
1373 1 : if (gimple_assign_rhs1 (stmt) != var)
1374 : {
1375 1 : gimple *stmt2;
1376 :
1377 1 : if (TREE_CODE (gimple_assign_rhs1 (stmt)) != SSA_NAME)
1378 : return;
1379 1 : stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt));
1380 1 : if (!gimple_assign_cast_p (stmt2)
1381 0 : || gimple_assign_rhs1 (stmt2) != var
1382 0 : || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt2))
1383 1 : || (TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt)))
1384 0 : != TYPE_PRECISION (TREE_TYPE (var))))
1385 : return;
1386 : }
1387 0 : cst = gimple_assign_rhs2 (stmt);
1388 0 : if (POINTER_TYPE_P (TREE_TYPE (var)))
1389 : {
1390 0 : struct ptr_info_def *pi = SSA_NAME_PTR_INFO (var);
1391 0 : if (pi && pi->misalign)
1392 0 : return;
1393 0 : wide_int w = wi::bit_not (wi::to_wide (cst));
1394 0 : unsigned int bits = wi::ctz (w);
1395 0 : if (bits == 0 || bits >= HOST_BITS_PER_INT)
1396 0 : return;
1397 0 : unsigned int align = 1U << bits;
1398 0 : if (pi == NULL || pi->align < align)
1399 0 : set_ptr_info_alignment (get_ptr_info (var), align, 0);
1400 0 : }
1401 : else
1402 0 : set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var),
1403 0 : wi::to_wide (cst)));
1404 : }
1405 :
1406 : /* Set global ranges that can be determined from the C->M edge:
1407 :
1408 : <bb C>:
1409 : ...
1410 : if (something)
1411 : goto <bb N>;
1412 : else
1413 : goto <bb M>;
1414 : <bb N>:
1415 : __builtin_unreachable ();
1416 : <bb M>:
1417 : */
1418 :
1419 : void
1420 23461626 : dom_opt_dom_walker::set_global_ranges_from_unreachable_edges (basic_block bb)
1421 : {
1422 23461626 : edge pred_e = single_pred_edge_ignoring_loop_edges (bb, false);
1423 23461626 : if (!pred_e)
1424 : return;
1425 :
1426 17413046 : gimple *stmt = *gsi_last_bb (pred_e->src);
1427 17413046 : if (!stmt
1428 14622875 : || gimple_code (stmt) != GIMPLE_COND
1429 29538975 : || !assert_unreachable_fallthru_edge_p (pred_e))
1430 17192769 : return;
1431 :
1432 220277 : tree name;
1433 627985 : FOR_EACH_GORI_EXPORT_NAME (m_ranger->gori_ssa (), pred_e->src, name)
1434 407708 : if (all_uses_feed_or_dominated_by_stmt (name, stmt)
1435 : // The condition must post-dominate the definition point.
1436 600515 : && (SSA_NAME_IS_DEFAULT_DEF (name)
1437 192381 : || (gimple_bb (SSA_NAME_DEF_STMT (name))
1438 192381 : == pred_e->src)))
1439 : {
1440 187606 : value_range r (TREE_TYPE (name));
1441 :
1442 187606 : if (m_ranger->range_on_edge (r, pred_e, name)
1443 187606 : && !r.varying_p ()
1444 361129 : && !r.undefined_p ())
1445 : {
1446 173458 : set_range_info (name, r);
1447 173458 : maybe_set_nonzero_bits (pred_e, name);
1448 : }
1449 187606 : }
1450 : }
1451 :
1452 : /* Record any equivalences created by the incoming edge to BB into
1453 : CONST_AND_COPIES and AVAIL_EXPRS_STACK. If BB has more than one
1454 : incoming edge, then no equivalence is created. */
1455 :
1456 : static void
1457 23461626 : record_equivalences_from_incoming_edge (basic_block bb,
1458 : class const_and_copies *const_and_copies,
1459 : class avail_exprs_stack *avail_exprs_stack,
1460 : bitmap blocks_on_stack)
1461 : {
1462 23461626 : edge e;
1463 23461626 : basic_block parent;
1464 :
1465 : /* If our parent block ended with a control statement, then we may be
1466 : able to record some equivalences based on which outgoing edge from
1467 : the parent was followed. */
1468 23461626 : parent = get_immediate_dominator (CDI_DOMINATORS, bb);
1469 :
1470 23461626 : e = single_pred_edge_ignoring_loop_edges (bb, true);
1471 :
1472 : /* If we had a single incoming edge from our parent block, then enter
1473 : any data associated with the edge into our tables. */
1474 23461626 : if (e && e->src == parent)
1475 17418689 : record_temporary_equivalences (e, const_and_copies, avail_exprs_stack,
1476 : blocks_on_stack);
1477 23461626 : }
1478 :
1479 : /* Dump statistics for the hash table HTAB. */
1480 :
1481 : static void
1482 35 : htab_statistics (FILE *file, const hash_table<expr_elt_hasher> &htab)
1483 : {
1484 66 : fprintf (file, "size " HOST_SIZE_T_PRINT_DEC ", " HOST_SIZE_T_PRINT_DEC
1485 : " elements, %f collision/search ratio\n",
1486 35 : (fmt_size_t) htab.size (),
1487 35 : (fmt_size_t) htab.elements (),
1488 : htab.collisions ());
1489 35 : }
1490 :
1491 : /* Dump SSA statistics on FILE. */
1492 :
1493 : static void
1494 35 : dump_dominator_optimization_stats (FILE *file,
1495 : hash_table<expr_elt_hasher> *avail_exprs)
1496 : {
1497 35 : fprintf (file, "Total number of statements: %6ld\n\n",
1498 : opt_stats.num_stmts);
1499 35 : fprintf (file, "Exprs considered for dominator optimizations: %6ld\n",
1500 : opt_stats.num_exprs_considered);
1501 :
1502 35 : fprintf (file, "\nHash table statistics:\n");
1503 :
1504 35 : fprintf (file, " avail_exprs: ");
1505 35 : htab_statistics (file, *avail_exprs);
1506 35 : }
1507 :
1508 :
1509 : /* Similarly, but assume that X and Y are the two operands of an EQ_EXPR.
1510 : This constrains the cases in which we may treat this as assignment. */
1511 :
1512 : static void
1513 13278345 : record_equality (tree x, tree y, class const_and_copies *const_and_copies)
1514 : {
1515 13278345 : tree prev_x = NULL, prev_y = NULL;
1516 :
1517 13278345 : if (tree_swap_operands_p (x, y))
1518 604644 : std::swap (x, y);
1519 :
1520 : /* Most of the time tree_swap_operands_p does what we want. But there
1521 : are cases where we know one operand is better for copy propagation than
1522 : the other. Given no other code cares about ordering of equality
1523 : comparison operators for that purpose, we just handle the special cases
1524 : here. */
1525 13278345 : if (TREE_CODE (x) == SSA_NAME && TREE_CODE (y) == SSA_NAME)
1526 : {
1527 : /* If one operand is a single use operand, then make it
1528 : X. This will preserve its single use properly and if this
1529 : conditional is eliminated, the computation of X can be
1530 : eliminated as well. */
1531 1109781 : if (has_single_use (y) && ! has_single_use (x))
1532 : std::swap (x, y);
1533 : }
1534 13278345 : if (TREE_CODE (x) == SSA_NAME)
1535 13278345 : prev_x = SSA_NAME_VALUE (x);
1536 13278345 : if (TREE_CODE (y) == SSA_NAME)
1537 1109781 : prev_y = SSA_NAME_VALUE (y);
1538 :
1539 : /* If one of the previous values is invariant, or invariant in more loops
1540 : (by depth), then use that.
1541 : Otherwise it doesn't matter which value we choose, just so
1542 : long as we canonicalize on one value. */
1543 13278345 : if (is_gimple_min_invariant (y))
1544 : ;
1545 1109781 : else if (is_gimple_min_invariant (x))
1546 : prev_x = x, x = y, y = prev_x, prev_x = prev_y;
1547 1109781 : else if (prev_x && is_gimple_min_invariant (prev_x))
1548 : x = y, y = prev_x, prev_x = prev_y;
1549 1018531 : else if (prev_y)
1550 13278345 : y = prev_y;
1551 :
1552 : /* After the swapping, we must have one SSA_NAME. */
1553 13278345 : if (TREE_CODE (x) != SSA_NAME)
1554 : return;
1555 :
1556 : /* For IEEE, -0.0 == 0.0, so we don't necessarily know the sign of a
1557 : variable compared against zero. If we're honoring signed zeros,
1558 : then we cannot record this value unless we know that the value is
1559 : nonzero. */
1560 13278345 : if (HONOR_SIGNED_ZEROS (x)
1561 13278345 : && (TREE_CODE (y) != REAL_CST
1562 169815 : || real_equal (&dconst0, &TREE_REAL_CST (y))))
1563 504 : return;
1564 :
1565 13277841 : const_and_copies->record_const_or_copy (x, y, prev_x);
1566 : }
1567 :
1568 : /* Returns true when STMT is a simple iv increment. It detects the
1569 : following situation:
1570 :
1571 : i_1 = phi (..., i_k)
1572 : [...]
1573 : i_j = i_{j-1} for each j : 2 <= j <= k-1
1574 : [...]
1575 : i_k = i_{k-1} +/- ... */
1576 :
1577 : bool
1578 42726985 : simple_iv_increment_p (gimple *stmt)
1579 : {
1580 42726985 : enum tree_code code;
1581 42726985 : tree lhs, preinc;
1582 42726985 : gimple *phi;
1583 42726985 : size_t i;
1584 :
1585 42726985 : if (gimple_code (stmt) != GIMPLE_ASSIGN)
1586 : return false;
1587 :
1588 32712553 : lhs = gimple_assign_lhs (stmt);
1589 32712553 : if (TREE_CODE (lhs) != SSA_NAME)
1590 : return false;
1591 :
1592 32712553 : code = gimple_assign_rhs_code (stmt);
1593 32712553 : if (code != PLUS_EXPR
1594 32712553 : && code != MINUS_EXPR
1595 32712553 : && code != POINTER_PLUS_EXPR)
1596 : return false;
1597 :
1598 7959688 : preinc = gimple_assign_rhs1 (stmt);
1599 7959688 : if (TREE_CODE (preinc) != SSA_NAME)
1600 : return false;
1601 :
1602 7685663 : phi = SSA_NAME_DEF_STMT (preinc);
1603 7711484 : while (gimple_code (phi) != GIMPLE_PHI)
1604 : {
1605 : /* Follow trivial copies, but not the DEF used in a back edge,
1606 : so that we don't prevent coalescing. */
1607 5207732 : if (!gimple_assign_ssa_name_copy_p (phi))
1608 : return false;
1609 25821 : preinc = gimple_assign_rhs1 (phi);
1610 25821 : phi = SSA_NAME_DEF_STMT (preinc);
1611 : }
1612 :
1613 4996280 : for (i = 0; i < gimple_phi_num_args (phi); i++)
1614 4027365 : if (gimple_phi_arg_def (phi, i) == lhs)
1615 : return true;
1616 :
1617 : return false;
1618 : }
1619 :
1620 : /* Propagate know values from SSA_NAME_VALUE into the PHI nodes of the
1621 : successors of BB. */
1622 :
1623 : static void
1624 23461626 : cprop_into_successor_phis (basic_block bb,
1625 : class const_and_copies *const_and_copies)
1626 : {
1627 23461626 : edge e;
1628 23461626 : edge_iterator ei;
1629 :
1630 55751699 : FOR_EACH_EDGE (e, ei, bb->succs)
1631 : {
1632 32290073 : int indx;
1633 32290073 : gphi_iterator gsi;
1634 :
1635 : /* If this is an abnormal edge, then we do not want to copy propagate
1636 : into the PHI alternative associated with this edge. */
1637 32290073 : if (e->flags & EDGE_ABNORMAL)
1638 18990834 : continue;
1639 :
1640 32276283 : gsi = gsi_start_phis (e->dest);
1641 32276283 : if (gsi_end_p (gsi))
1642 18977044 : continue;
1643 :
1644 : /* We may have an equivalence associated with this edge. While
1645 : we cannot propagate it into non-dominated blocks, we can
1646 : propagate them into PHIs in non-dominated blocks. */
1647 :
1648 : /* Push the unwind marker so we can reset the const and copies
1649 : table back to its original state after processing this edge. */
1650 13299239 : const_and_copies->push_marker ();
1651 :
1652 : /* Extract and record any simple NAME = VALUE equivalences.
1653 :
1654 : Don't bother with [01] = COND equivalences, they're not useful
1655 : here. */
1656 13299239 : class edge_info *edge_info = (class edge_info *) e->aux;
1657 :
1658 13299239 : if (edge_info)
1659 : {
1660 : edge_info::equiv_pair *seq;
1661 8390712 : for (int i = 0; edge_info->simple_equivalences.iterate (i, &seq); ++i)
1662 : {
1663 3189517 : tree lhs = seq->first;
1664 3189517 : tree rhs = seq->second;
1665 :
1666 3189517 : if (lhs && TREE_CODE (lhs) == SSA_NAME)
1667 3189517 : const_and_copies->record_const_or_copy (lhs, rhs);
1668 : }
1669 :
1670 : }
1671 :
1672 13299239 : indx = e->dest_idx;
1673 36670350 : for ( ; !gsi_end_p (gsi); gsi_next (&gsi))
1674 : {
1675 23371111 : tree new_val;
1676 23371111 : use_operand_p orig_p;
1677 23371111 : tree orig_val;
1678 23371111 : gphi *phi = gsi.phi ();
1679 :
1680 : /* The alternative may be associated with a constant, so verify
1681 : it is an SSA_NAME before doing anything with it. */
1682 23371111 : orig_p = gimple_phi_arg_imm_use_ptr (phi, indx);
1683 23371111 : orig_val = get_use_from_ptr (orig_p);
1684 23371111 : if (TREE_CODE (orig_val) != SSA_NAME)
1685 3223475 : continue;
1686 :
1687 : /* If we have *ORIG_P in our constant/copy table, then replace
1688 : ORIG_P with its value in our constant/copy table. */
1689 20147636 : new_val = SSA_NAME_VALUE (orig_val);
1690 20147636 : if (new_val
1691 20147636 : && new_val != orig_val
1692 20147636 : && may_propagate_copy (orig_val, new_val))
1693 1131694 : propagate_value (orig_p, new_val);
1694 : }
1695 :
1696 13299239 : const_and_copies->pop_to_marker ();
1697 : }
1698 23461626 : }
1699 :
1700 : edge
1701 23461626 : dom_opt_dom_walker::before_dom_children (basic_block bb)
1702 : {
1703 23461626 : gimple_stmt_iterator gsi;
1704 :
1705 23461626 : if (dump_file && (dump_flags & TDF_DETAILS))
1706 736 : fprintf (dump_file, "\n\nOptimizing block #%d\n\n", bb->index);
1707 :
1708 : /* Push a marker on the stacks of local information so that we know how
1709 : far to unwind when we finalize this block. */
1710 23461626 : m_avail_exprs_stack->push_marker ();
1711 23461626 : m_const_and_copies->push_marker ();
1712 23461626 : bitmap_set_bit (m_state->get_blocks_on_stack (), bb->index);
1713 :
1714 23461626 : record_equivalences_from_incoming_edge (bb, m_const_and_copies,
1715 : m_avail_exprs_stack,
1716 23461626 : m_state->get_blocks_on_stack ());
1717 23461626 : set_global_ranges_from_unreachable_edges (bb);
1718 :
1719 : /* PHI nodes can create equivalences too. */
1720 23461626 : record_equivalences_from_phis (bb);
1721 :
1722 : /* Create equivalences from redundant PHIs. PHIs are only truly
1723 : redundant when they exist in the same block, so push another
1724 : marker and unwind right afterwards. */
1725 23461626 : m_avail_exprs_stack->push_marker ();
1726 32287792 : for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1727 8826166 : eliminate_redundant_computations (&gsi, m_const_and_copies,
1728 : m_avail_exprs_stack);
1729 23461626 : m_avail_exprs_stack->pop_to_marker ();
1730 :
1731 23461626 : edge taken_edge = NULL;
1732 : /* Initialize visited flag ahead of us, it has undefined state on
1733 : pass entry. */
1734 216751055 : for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1735 169827803 : gimple_set_visited (gsi_stmt (gsi), false);
1736 362991597 : for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
1737 : {
1738 : /* Do not optimize a stmt twice, substitution might end up with
1739 : _3 = _3 which is not valid. */
1740 339529971 : if (gimple_visited_p (gsi_stmt (gsi)))
1741 : {
1742 169701962 : gsi_next (&gsi);
1743 169701962 : continue;
1744 : }
1745 :
1746 169828009 : bool removed_p = false;
1747 169828009 : taken_edge = this->optimize_stmt (bb, &gsi, &removed_p);
1748 169828009 : if (!removed_p)
1749 169701962 : gimple_set_visited (gsi_stmt (gsi), true);
1750 :
1751 : /* Go back and visit stmts inserted by folding after substituting
1752 : into the stmt at gsi. */
1753 169828009 : if (gsi_end_p (gsi))
1754 : {
1755 2811 : gcc_checking_assert (removed_p);
1756 2811 : gsi = gsi_last_bb (bb);
1757 5212 : while (!gsi_end_p (gsi) && !gimple_visited_p (gsi_stmt (gsi)))
1758 2811 : gsi_prev (&gsi);
1759 : }
1760 : else
1761 : {
1762 169825404 : do
1763 : {
1764 169825404 : gsi_prev (&gsi);
1765 : }
1766 339650602 : while (!gsi_end_p (gsi) && !gimple_visited_p (gsi_stmt (gsi)));
1767 : }
1768 169828009 : if (gsi_end_p (gsi))
1769 38680450 : gsi = gsi_start_bb (bb);
1770 : else
1771 150487784 : gsi_next (&gsi);
1772 : }
1773 :
1774 : /* Now prepare to process dominated blocks. */
1775 23461626 : record_edge_info (bb);
1776 23461626 : cprop_into_successor_phis (bb, m_const_and_copies);
1777 23461626 : if (taken_edge && !dbg_cnt (dom_unreachable_edges))
1778 : return NULL;
1779 :
1780 : return taken_edge;
1781 : }
1782 :
1783 : /* We have finished processing the dominator children of BB, perform
1784 : any finalization actions in preparation for leaving this node in
1785 : the dominator tree. */
1786 :
1787 : void
1788 23461626 : dom_opt_dom_walker::after_dom_children (basic_block bb)
1789 : {
1790 23461626 : m_threader->thread_outgoing_edges (bb);
1791 23461626 : bitmap_clear_bit (m_state->get_blocks_on_stack (), bb->index);
1792 23461626 : m_avail_exprs_stack->pop_to_marker ();
1793 23461626 : m_const_and_copies->pop_to_marker ();
1794 23461626 : }
1795 :
1796 : /* Search for redundant computations in STMT. If any are found, then
1797 : replace them with the variable holding the result of the computation.
1798 :
1799 : If safe, record this expression into AVAIL_EXPRS_STACK and
1800 : CONST_AND_COPIES. */
1801 :
1802 : static void
1803 63215116 : eliminate_redundant_computations (gimple_stmt_iterator* gsi,
1804 : class const_and_copies *const_and_copies,
1805 : class avail_exprs_stack *avail_exprs_stack)
1806 : {
1807 63215116 : tree expr_type;
1808 63215116 : tree cached_lhs;
1809 63215116 : tree def;
1810 63215116 : bool insert = true;
1811 63215116 : bool assigns_var_p = false;
1812 :
1813 63215116 : gimple *stmt = gsi_stmt (*gsi);
1814 :
1815 63215116 : if (gimple_code (stmt) == GIMPLE_PHI)
1816 8826166 : def = gimple_phi_result (stmt);
1817 : else
1818 54388950 : def = gimple_get_lhs (stmt);
1819 :
1820 : /* Certain expressions on the RHS can be optimized away, but cannot
1821 : themselves be entered into the hash tables. */
1822 63215116 : if (! def
1823 54187222 : || TREE_CODE (def) != SSA_NAME
1824 41618095 : || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def)
1825 32790698 : || gimple_vdef (stmt)
1826 : /* Do not record equivalences for increments of ivs. This would create
1827 : overlapping live ranges for a very questionable gain. */
1828 104822746 : || simple_iv_increment_p (stmt))
1829 : insert = false;
1830 :
1831 : /* Check if the expression has been computed before. */
1832 63215116 : cached_lhs = avail_exprs_stack->lookup_avail_expr (stmt, insert, true);
1833 :
1834 63215116 : opt_stats.num_exprs_considered++;
1835 :
1836 : /* Get the type of the expression we are trying to optimize. */
1837 63215116 : if (is_gimple_assign (stmt))
1838 : {
1839 44117545 : expr_type = TREE_TYPE (gimple_assign_lhs (stmt));
1840 44117545 : assigns_var_p = true;
1841 : }
1842 19097571 : else if (gimple_code (stmt) == GIMPLE_COND)
1843 8992201 : expr_type = boolean_type_node;
1844 10105370 : else if (is_gimple_call (stmt))
1845 : {
1846 1243511 : gcc_assert (gimple_call_lhs (stmt));
1847 1243511 : expr_type = TREE_TYPE (gimple_call_lhs (stmt));
1848 1243511 : assigns_var_p = true;
1849 : }
1850 8861859 : else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt))
1851 35693 : expr_type = TREE_TYPE (gimple_switch_index (swtch_stmt));
1852 8826166 : else if (gimple_code (stmt) == GIMPLE_PHI)
1853 : /* We can't propagate into a phi, so the logic below doesn't apply.
1854 : Instead record an equivalence between the cached LHS and the
1855 : PHI result of this statement, provided they are in the same block.
1856 : This should be sufficient to kill the redundant phi. */
1857 : {
1858 8826166 : if (def && cached_lhs)
1859 22165 : const_and_copies->record_const_or_copy (def, cached_lhs);
1860 8826166 : return;
1861 : }
1862 : else
1863 0 : gcc_unreachable ();
1864 :
1865 54388950 : if (!cached_lhs)
1866 : return;
1867 :
1868 : /* It is safe to ignore types here since we have already done
1869 : type checking in the hashing and equality routines. In fact
1870 : type checking here merely gets in the way of constant
1871 : propagation. Also, make sure that it is safe to propagate
1872 : CACHED_LHS into the expression in STMT. */
1873 413390 : if ((TREE_CODE (cached_lhs) != SSA_NAME
1874 38749 : && (assigns_var_p
1875 3145 : || useless_type_conversion_p (expr_type, TREE_TYPE (cached_lhs))))
1876 413390 : || may_propagate_copy_into_stmt (stmt, cached_lhs))
1877 : {
1878 400742 : gcc_checking_assert (TREE_CODE (cached_lhs) == SSA_NAME
1879 : || is_gimple_min_invariant (cached_lhs));
1880 :
1881 400742 : if (dump_file && (dump_flags & TDF_DETAILS))
1882 : {
1883 16 : fprintf (dump_file, " Replaced redundant expr '");
1884 16 : print_gimple_expr (dump_file, stmt, 0, dump_flags);
1885 16 : fprintf (dump_file, "' with '");
1886 16 : print_generic_expr (dump_file, cached_lhs, dump_flags);
1887 16 : fprintf (dump_file, "'\n");
1888 : }
1889 :
1890 400742 : opt_stats.num_re++;
1891 :
1892 400742 : if (assigns_var_p
1893 400742 : && !useless_type_conversion_p (expr_type, TREE_TYPE (cached_lhs)))
1894 0 : cached_lhs = fold_convert (expr_type, cached_lhs);
1895 :
1896 400742 : propagate_tree_value_into_stmt (gsi, cached_lhs);
1897 :
1898 : /* Since it is always necessary to mark the result as modified,
1899 : perhaps we should move this into propagate_tree_value_into_stmt
1900 : itself. */
1901 400742 : gimple_set_modified (gsi_stmt (*gsi), true);
1902 : }
1903 : }
1904 :
1905 : /* STMT, a GIMPLE_ASSIGN, may create certain equivalences, in either
1906 : the available expressions table or the const_and_copies table.
1907 : Detect and record those equivalences into AVAIL_EXPRS_STACK.
1908 :
1909 : We handle only very simple copy equivalences here. The heavy
1910 : lifing is done by eliminate_redundant_computations. */
1911 :
1912 : static void
1913 47448421 : record_equivalences_from_stmt (gimple *stmt, int may_optimize_p,
1914 : class avail_exprs_stack *avail_exprs_stack)
1915 : {
1916 47448421 : tree lhs;
1917 47448421 : enum tree_code lhs_code;
1918 :
1919 47448421 : gcc_assert (is_gimple_assign (stmt));
1920 :
1921 47448421 : lhs = gimple_assign_lhs (stmt);
1922 47448421 : lhs_code = TREE_CODE (lhs);
1923 :
1924 47448421 : if (lhs_code == SSA_NAME
1925 47448421 : && gimple_assign_single_p (stmt))
1926 : {
1927 15611746 : tree rhs = gimple_assign_rhs1 (stmt);
1928 :
1929 : /* If the RHS of the assignment is a constant or another variable that
1930 : may be propagated, register it in the CONST_AND_COPIES table. We
1931 : do not need to record unwind data for this, since this is a true
1932 : assignment and not an equivalence inferred from a comparison. All
1933 : uses of this ssa name are dominated by this assignment, so unwinding
1934 : just costs time and space. */
1935 15611746 : if (may_optimize_p
1936 15611746 : && (TREE_CODE (rhs) == SSA_NAME
1937 13580547 : || is_gimple_min_invariant (rhs)))
1938 : {
1939 1997917 : rhs = dom_valueize (rhs);
1940 :
1941 1997917 : if (dump_file && (dump_flags & TDF_DETAILS))
1942 : {
1943 74 : fprintf (dump_file, "==== ASGN ");
1944 74 : print_generic_expr (dump_file, lhs);
1945 74 : fprintf (dump_file, " = ");
1946 74 : print_generic_expr (dump_file, rhs);
1947 74 : fprintf (dump_file, "\n");
1948 : }
1949 :
1950 1997917 : set_ssa_name_value (lhs, rhs);
1951 : }
1952 : }
1953 :
1954 : /* Make sure we can propagate &x + CST. */
1955 47448421 : if (lhs_code == SSA_NAME
1956 32179246 : && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
1957 1646856 : && TREE_CODE (gimple_assign_rhs1 (stmt)) == ADDR_EXPR
1958 47643082 : && TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST)
1959 : {
1960 4541 : tree op0 = gimple_assign_rhs1 (stmt);
1961 4541 : tree op1 = gimple_assign_rhs2 (stmt);
1962 4541 : tree new_rhs
1963 9082 : = build1 (ADDR_EXPR, TREE_TYPE (op0),
1964 4541 : fold_build2 (MEM_REF, TREE_TYPE (TREE_TYPE (op0)),
1965 : unshare_expr (op0), fold_convert (ptr_type_node,
1966 : op1)));
1967 4541 : if (dump_file && (dump_flags & TDF_DETAILS))
1968 : {
1969 0 : fprintf (dump_file, "==== ASGN ");
1970 0 : print_generic_expr (dump_file, lhs);
1971 0 : fprintf (dump_file, " = ");
1972 0 : print_generic_expr (dump_file, new_rhs);
1973 0 : fprintf (dump_file, "\n");
1974 : }
1975 :
1976 4541 : set_ssa_name_value (lhs, new_rhs);
1977 : }
1978 :
1979 : /* A memory store, even an aliased store, creates a useful
1980 : equivalence. By exchanging the LHS and RHS, creating suitable
1981 : vops and recording the result in the available expression table,
1982 : we may be able to expose more redundant loads. */
1983 91444816 : if (!gimple_has_volatile_ops (stmt)
1984 71358200 : && gimple_references_memory_p (stmt)
1985 23909779 : && gimple_assign_single_p (stmt)
1986 23909779 : && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
1987 18732069 : || is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
1988 58883142 : && !is_gimple_reg (lhs))
1989 : {
1990 11262383 : tree rhs = gimple_assign_rhs1 (stmt);
1991 11262383 : gassign *new_stmt;
1992 :
1993 : /* Build a new statement with the RHS and LHS exchanged. */
1994 11262383 : if (TREE_CODE (rhs) == SSA_NAME)
1995 : {
1996 : /* NOTE tuples. The call to gimple_build_assign below replaced
1997 : a call to build_gimple_modify_stmt, which did not set the
1998 : SSA_NAME_DEF_STMT on the LHS of the assignment. Doing so
1999 : may cause an SSA validation failure, as the LHS may be a
2000 : default-initialized name and should have no definition. I'm
2001 : a bit dubious of this, as the artificial statement that we
2002 : generate here may in fact be ill-formed, but it is simply
2003 : used as an internal device in this pass, and never becomes
2004 : part of the CFG. */
2005 5036705 : gimple *defstmt = SSA_NAME_DEF_STMT (rhs);
2006 5036705 : new_stmt = gimple_build_assign (rhs, lhs);
2007 5036705 : SSA_NAME_DEF_STMT (rhs) = defstmt;
2008 : }
2009 : else
2010 6225678 : new_stmt = gimple_build_assign (rhs, lhs);
2011 :
2012 22524766 : gimple_set_vuse (new_stmt, gimple_vdef (stmt));
2013 :
2014 : /* Finally enter the statement into the available expression
2015 : table. */
2016 11262383 : avail_exprs_stack->lookup_avail_expr (new_stmt, true, true);
2017 : }
2018 47448421 : }
2019 :
2020 : /* Replace *OP_P in STMT with any known equivalent value for *OP_P from
2021 : CONST_AND_COPIES. */
2022 :
2023 : static void
2024 79824648 : cprop_operand (gimple *stmt, use_operand_p op_p, range_query *query)
2025 : {
2026 79824648 : tree val;
2027 79824648 : tree op = USE_FROM_PTR (op_p);
2028 :
2029 : /* If the operand has a known constant value or it is known to be a
2030 : copy of some other variable, use the value or copy stored in
2031 : CONST_AND_COPIES. */
2032 79824648 : val = SSA_NAME_VALUE (op);
2033 53838222 : if (!val)
2034 : {
2035 75907924 : value_range r (TREE_TYPE (op));
2036 75907924 : tree single;
2037 149598976 : if (query->range_of_expr (r, op, stmt) && r.singleton_p (&single))
2038 23155 : val = single;
2039 75907924 : }
2040 :
2041 79824648 : if (val && val != op)
2042 : {
2043 : /* Certain operands are not allowed to be copy propagated due
2044 : to their interaction with exception handling and some GCC
2045 : extensions. */
2046 3938016 : if (!may_propagate_copy (op, val))
2047 : return;
2048 :
2049 : /* Do not propagate copies into BIVs.
2050 : See PR23821 and PR62217 for how this can disturb IV and
2051 : number of iteration analysis. */
2052 3936466 : if (TREE_CODE (val) != INTEGER_CST)
2053 : {
2054 3197028 : gimple *def = SSA_NAME_DEF_STMT (op);
2055 3197028 : if (gimple_code (def) == GIMPLE_PHI
2056 3197028 : && gimple_bb (def)->loop_father->header == gimple_bb (def))
2057 : return;
2058 : }
2059 :
2060 : /* Dump details. */
2061 3926521 : if (dump_file && (dump_flags & TDF_DETAILS))
2062 : {
2063 76 : fprintf (dump_file, " Replaced '");
2064 76 : print_generic_expr (dump_file, op, dump_flags);
2065 76 : fprintf (dump_file, "' with %s '",
2066 76 : (TREE_CODE (val) != SSA_NAME ? "constant" : "variable"));
2067 76 : print_generic_expr (dump_file, val, dump_flags);
2068 76 : fprintf (dump_file, "'\n");
2069 : }
2070 :
2071 3926521 : if (TREE_CODE (val) != SSA_NAME)
2072 922653 : opt_stats.num_const_prop++;
2073 : else
2074 3003868 : opt_stats.num_copy_prop++;
2075 :
2076 3926521 : propagate_value (op_p, val);
2077 :
2078 : /* And note that we modified this statement. This is now
2079 : safe, even if we changed virtual operands since we will
2080 : rescan the statement and rewrite its operands again. */
2081 3926521 : gimple_set_modified (stmt, true);
2082 : }
2083 : }
2084 :
2085 : /* CONST_AND_COPIES is a table which maps an SSA_NAME to the current
2086 : known value for that SSA_NAME (or NULL if no value is known).
2087 :
2088 : Propagate values from CONST_AND_COPIES into the uses, vuses and
2089 : vdef_ops of STMT. */
2090 :
2091 : static void
2092 169828009 : cprop_into_stmt (gimple *stmt, range_query *query)
2093 : {
2094 169828009 : use_operand_p op_p;
2095 169828009 : ssa_op_iter iter;
2096 169828009 : tree last_copy_propagated_op = NULL;
2097 :
2098 249653316 : FOR_EACH_SSA_USE_OPERAND (op_p, stmt, iter, SSA_OP_USE)
2099 : {
2100 79825307 : tree old_op = USE_FROM_PTR (op_p);
2101 :
2102 : /* If we have A = B and B = A in the copy propagation tables
2103 : (due to an equality comparison), avoid substituting B for A
2104 : then A for B in the trivially discovered cases. This allows
2105 : optimization of statements were A and B appear as input
2106 : operands. */
2107 79825307 : if (old_op != last_copy_propagated_op)
2108 : {
2109 79824648 : cprop_operand (stmt, op_p, query);
2110 :
2111 79824648 : tree new_op = USE_FROM_PTR (op_p);
2112 79824648 : if (new_op != old_op && TREE_CODE (new_op) == SSA_NAME)
2113 79825307 : last_copy_propagated_op = new_op;
2114 : }
2115 : }
2116 169828009 : }
2117 :
2118 : /* If STMT contains a relational test, try to convert it into an
2119 : equality test if there is only a single value which can ever
2120 : make the test true.
2121 :
2122 : For example, if the expression hash table contains:
2123 :
2124 : TRUE = (i <= 1)
2125 :
2126 : And we have a test within statement of i >= 1, then we can safely
2127 : rewrite the test as i == 1 since there only a single value where
2128 : the test is true.
2129 :
2130 : This is similar to code in VRP. */
2131 :
2132 : void
2133 54262903 : dom_opt_dom_walker::test_for_singularity (gimple *stmt,
2134 : avail_exprs_stack *avail_exprs_stack)
2135 : {
2136 : /* We want to support gimple conditionals as well as assignments
2137 : where the RHS contains a conditional. */
2138 54262903 : if (is_gimple_assign (stmt) || gimple_code (stmt) == GIMPLE_COND)
2139 : {
2140 52988596 : enum tree_code code = ERROR_MARK;
2141 52988596 : tree lhs, rhs;
2142 :
2143 : /* Extract the condition of interest from both forms we support. */
2144 52988596 : if (is_gimple_assign (stmt))
2145 : {
2146 43996395 : code = gimple_assign_rhs_code (stmt);
2147 43996395 : lhs = gimple_assign_rhs1 (stmt);
2148 43996395 : rhs = gimple_assign_rhs2 (stmt);
2149 : }
2150 8992201 : else if (gimple_code (stmt) == GIMPLE_COND)
2151 : {
2152 8992201 : code = gimple_cond_code (as_a <gcond *> (stmt));
2153 8992201 : lhs = gimple_cond_lhs (as_a <gcond *> (stmt));
2154 8992201 : rhs = gimple_cond_rhs (as_a <gcond *> (stmt));
2155 : }
2156 :
2157 : /* We're looking for a relational test using LE/GE. Also note we can
2158 : canonicalize LT/GT tests against constants into LE/GT tests. */
2159 52988596 : if (code == LE_EXPR || code == GE_EXPR
2160 52307552 : || ((code == LT_EXPR || code == GT_EXPR)
2161 1709090 : && TREE_CODE (rhs) == INTEGER_CST))
2162 : {
2163 : /* For LT_EXPR and GT_EXPR, canonicalize to LE_EXPR and GE_EXPR. */
2164 912567 : if (code == LT_EXPR)
2165 128130 : rhs = fold_build2 (MINUS_EXPR, TREE_TYPE (rhs),
2166 : rhs, build_int_cst (TREE_TYPE (rhs), 1));
2167 :
2168 1593611 : if (code == GT_EXPR)
2169 784437 : rhs = fold_build2 (PLUS_EXPR, TREE_TYPE (rhs),
2170 : rhs, build_int_cst (TREE_TYPE (rhs), 1));
2171 :
2172 : /* Determine the code we want to check for in the hash table. */
2173 1593611 : enum tree_code test_code;
2174 1593611 : if (code == GE_EXPR || code == GT_EXPR)
2175 : test_code = LE_EXPR;
2176 : else
2177 547977 : test_code = GE_EXPR;
2178 :
2179 : /* Update the dummy statement so we can query the hash tables. */
2180 1593611 : gimple_cond_set_code (m_dummy_cond, test_code);
2181 1593611 : gimple_cond_set_lhs (m_dummy_cond, lhs);
2182 1593611 : gimple_cond_set_rhs (m_dummy_cond, rhs);
2183 1593611 : tree cached_lhs
2184 1593611 : = avail_exprs_stack->lookup_avail_expr (m_dummy_cond,
2185 : false, false);
2186 :
2187 : /* If the lookup returned 1 (true), then the expression we
2188 : queried was in the hash table. As a result there is only
2189 : one value that makes the original conditional true. Update
2190 : STMT accordingly. */
2191 1593611 : if (cached_lhs && integer_onep (cached_lhs))
2192 : {
2193 1341 : if (is_gimple_assign (stmt))
2194 : {
2195 97 : gimple_assign_set_rhs_code (stmt, EQ_EXPR);
2196 97 : gimple_assign_set_rhs2 (stmt, rhs);
2197 97 : gimple_set_modified (stmt, true);
2198 : }
2199 : else
2200 : {
2201 1244 : gimple_set_modified (stmt, true);
2202 1244 : gimple_cond_set_code (as_a <gcond *> (stmt), EQ_EXPR);
2203 1244 : gimple_cond_set_rhs (as_a <gcond *> (stmt), rhs);
2204 1244 : gimple_set_modified (stmt, true);
2205 : }
2206 : }
2207 : }
2208 : }
2209 54262903 : }
2210 :
2211 : /* If STMT is a comparison of two uniform vectors reduce it to a comparison
2212 : of scalar objects, otherwise leave STMT unchanged. */
2213 :
2214 : static void
2215 169828009 : reduce_vector_comparison_to_scalar_comparison (gimple *stmt)
2216 : {
2217 169828009 : if (gimple_code (stmt) == GIMPLE_COND)
2218 : {
2219 9093956 : tree lhs = gimple_cond_lhs (stmt);
2220 9093956 : tree rhs = gimple_cond_rhs (stmt);
2221 :
2222 : /* We may have a vector comparison where both arms are uniform
2223 : vectors. If so, we can simplify the vector comparison down
2224 : to a scalar comparison. */
2225 9093956 : if (VECTOR_TYPE_P (TREE_TYPE (lhs))
2226 9093956 : && VECTOR_TYPE_P (TREE_TYPE (rhs)))
2227 : {
2228 : /* If either operand is an SSA_NAME, then look back to its
2229 : defining statement to try and get at a suitable source. */
2230 2575 : if (TREE_CODE (rhs) == SSA_NAME)
2231 : {
2232 0 : gimple *def_stmt = SSA_NAME_DEF_STMT (rhs);
2233 0 : if (gimple_assign_single_p (def_stmt))
2234 0 : rhs = gimple_assign_rhs1 (def_stmt);
2235 : }
2236 :
2237 2575 : if (TREE_CODE (lhs) == SSA_NAME)
2238 : {
2239 2575 : gimple *def_stmt = SSA_NAME_DEF_STMT (lhs);
2240 2575 : if (gimple_assign_single_p (def_stmt))
2241 6 : lhs = gimple_assign_rhs1 (def_stmt);
2242 : }
2243 :
2244 : /* Now see if they are both uniform vectors and if so replace
2245 : the vector comparison with a scalar comparison. */
2246 2575 : tree rhs_elem = rhs ? uniform_vector_p (rhs) : NULL_TREE;
2247 2575 : tree lhs_elem = lhs ? uniform_vector_p (lhs) : NULL_TREE;
2248 2575 : if (rhs_elem && lhs_elem)
2249 : {
2250 3 : if (dump_file && dump_flags & TDF_DETAILS)
2251 : {
2252 0 : fprintf (dump_file, "Reducing vector comparison: ");
2253 0 : print_gimple_stmt (dump_file, stmt, 0);
2254 : }
2255 :
2256 3 : gimple_cond_set_rhs (as_a <gcond *>(stmt), rhs_elem);
2257 3 : gimple_cond_set_lhs (as_a <gcond *>(stmt), lhs_elem);
2258 3 : gimple_set_modified (stmt, true);
2259 :
2260 3 : if (dump_file && dump_flags & TDF_DETAILS)
2261 : {
2262 0 : fprintf (dump_file, "To scalar equivalent: ");
2263 0 : print_gimple_stmt (dump_file, stmt, 0);
2264 0 : fprintf (dump_file, "\n");
2265 : }
2266 : }
2267 : }
2268 : }
2269 169828009 : }
2270 :
2271 : /* If possible, rewrite the conditional as TRUE or FALSE, and return
2272 : the taken edge. Otherwise, return NULL. */
2273 :
2274 : edge
2275 9033918 : dom_opt_dom_walker::fold_cond (gcond *cond)
2276 : {
2277 9033918 : simplify_using_ranges simplify (m_ranger);
2278 9033918 : if (simplify.fold_cond (cond))
2279 : {
2280 101755 : basic_block bb = gimple_bb (cond);
2281 101755 : if (gimple_cond_true_p (cond))
2282 24367 : return find_taken_edge (bb, boolean_true_node);
2283 77388 : if (gimple_cond_false_p (cond))
2284 77388 : return find_taken_edge (bb, boolean_false_node);
2285 : }
2286 : return NULL;
2287 9033918 : }
2288 :
2289 : /* Optimize the statement in block BB pointed to by iterator SI.
2290 :
2291 : We try to perform some simplistic global redundancy elimination and
2292 : constant propagation:
2293 :
2294 : 1- To detect global redundancy, we keep track of expressions that have
2295 : been computed in this block and its dominators. If we find that the
2296 : same expression is computed more than once, we eliminate repeated
2297 : computations by using the target of the first one.
2298 :
2299 : 2- Constant values and copy assignments. This is used to do very
2300 : simplistic constant and copy propagation. When a constant or copy
2301 : assignment is found, we map the value on the RHS of the assignment to
2302 : the variable in the LHS in the CONST_AND_COPIES table.
2303 :
2304 : 3- Very simple redundant store elimination is performed.
2305 :
2306 : 4- We can simplify a condition to a constant or from a relational
2307 : condition to an equality condition. */
2308 :
2309 : edge
2310 169828009 : dom_opt_dom_walker::optimize_stmt (basic_block bb, gimple_stmt_iterator *si,
2311 : bool *removed_p)
2312 : {
2313 169828009 : gimple *stmt, *old_stmt;
2314 169828009 : bool may_optimize_p;
2315 169828009 : bool modified_p = false;
2316 169828009 : bool was_noreturn;
2317 169828009 : edge retval = NULL;
2318 :
2319 169828009 : old_stmt = stmt = gsi_stmt (*si);
2320 169828009 : was_noreturn = is_gimple_call (stmt) && gimple_call_noreturn_p (stmt);
2321 :
2322 169828009 : if (dump_file && (dump_flags & TDF_DETAILS))
2323 : {
2324 1606 : fprintf (dump_file, "Optimizing statement ");
2325 1606 : print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
2326 : }
2327 :
2328 : /* STMT may be a comparison of uniform vectors that we can simplify
2329 : down to a comparison of scalars. Do that transformation first
2330 : so that all the scalar optimizations from here onward apply. */
2331 169828009 : reduce_vector_comparison_to_scalar_comparison (stmt);
2332 :
2333 169828009 : update_stmt_if_modified (stmt);
2334 169828009 : opt_stats.num_stmts++;
2335 :
2336 : /* Const/copy propagate into USES, VUSES and the RHS of VDEFs. */
2337 169828009 : cprop_into_stmt (stmt, m_ranger);
2338 :
2339 : /* If the statement has been modified with constant replacements,
2340 : fold its RHS before checking for redundant computations. */
2341 339359879 : if (gimple_modified_p (stmt))
2342 : {
2343 3764781 : tree rhs = NULL;
2344 :
2345 : /* Try to fold the statement making sure that STMT is kept
2346 : up to date. */
2347 3764781 : if (fold_stmt (si))
2348 : {
2349 385931 : stmt = gsi_stmt (*si);
2350 385931 : gimple_set_modified (stmt, true);
2351 :
2352 385931 : if (dump_file && (dump_flags & TDF_DETAILS))
2353 : {
2354 12 : fprintf (dump_file, " Folded to: ");
2355 12 : print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
2356 : }
2357 : }
2358 :
2359 : /* We only need to consider cases that can yield a gimple operand. */
2360 3764781 : if (gimple_assign_single_p (stmt))
2361 1406228 : rhs = gimple_assign_rhs1 (stmt);
2362 2358553 : else if (gimple_code (stmt) == GIMPLE_GOTO)
2363 1 : rhs = gimple_goto_dest (stmt);
2364 172186561 : else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt))
2365 : /* This should never be an ADDR_EXPR. */
2366 2544 : rhs = gimple_switch_index (swtch_stmt);
2367 :
2368 1408773 : if (rhs && TREE_CODE (rhs) == ADDR_EXPR)
2369 84591 : recompute_tree_invariant_for_addr_expr (rhs);
2370 :
2371 : /* Indicate that maybe_clean_or_replace_eh_stmt needs to be called,
2372 : even if fold_stmt updated the stmt already and thus cleared
2373 : gimple_modified_p flag on it. */
2374 : modified_p = true;
2375 : }
2376 :
2377 : /* Check for redundant computations. Do this optimization only
2378 : for assignments that have no volatile ops and conditionals. */
2379 169828009 : may_optimize_p = (!gimple_has_side_effects (stmt)
2380 169828009 : && (is_gimple_assign (stmt)
2381 112714991 : || (is_gimple_call (stmt)
2382 1243889 : && gimple_call_lhs (stmt) != NULL_TREE)
2383 111471424 : || gimple_code (stmt) == GIMPLE_COND
2384 102377468 : || gimple_code (stmt) == GIMPLE_SWITCH));
2385 :
2386 54490705 : if (may_optimize_p)
2387 : {
2388 54490705 : if (gimple_code (stmt) == GIMPLE_CALL)
2389 : {
2390 : /* Resolve __builtin_constant_p. If it hasn't been
2391 : folded to integer_one_node by now, it's fairly
2392 : certain that the value simply isn't constant. */
2393 1243567 : tree callee = gimple_call_fndecl (stmt);
2394 1243567 : if (callee
2395 1243567 : && fndecl_built_in_p (callee, BUILT_IN_CONSTANT_P))
2396 : {
2397 56 : propagate_tree_value_into_stmt (si, integer_zero_node);
2398 56 : stmt = gsi_stmt (*si);
2399 : }
2400 : }
2401 :
2402 54490705 : if (gimple_code (stmt) == GIMPLE_COND)
2403 : {
2404 9093956 : tree lhs = gimple_cond_lhs (stmt);
2405 9093956 : tree rhs = gimple_cond_rhs (stmt);
2406 :
2407 : /* If the LHS has a range [0..1] and the RHS has a range ~[0..1],
2408 : then this conditional is computable at compile time. We can just
2409 : shove either 0 or 1 into the LHS, mark the statement as modified
2410 : and all the right things will just happen below.
2411 :
2412 : Note this would apply to any case where LHS has a range
2413 : narrower than its type implies and RHS is outside that
2414 : narrower range. Future work. */
2415 9093956 : if (TREE_CODE (lhs) == SSA_NAME
2416 9033940 : && ssa_name_has_boolean_range (lhs)
2417 1004168 : && TREE_CODE (rhs) == INTEGER_CST
2418 10067857 : && ! (integer_zerop (rhs) || integer_onep (rhs)))
2419 : {
2420 22 : gimple_cond_set_lhs (as_a <gcond *> (stmt),
2421 22 : fold_convert (TREE_TYPE (lhs),
2422 : integer_zero_node));
2423 22 : gimple_set_modified (stmt, true);
2424 : }
2425 9093934 : else if (TREE_CODE (lhs) == SSA_NAME)
2426 : {
2427 : /* Exploiting EVRP data is not yet fully integrated into DOM
2428 : but we need to do something for this case to avoid regressing
2429 : udr4.f90 and new1.C which have unexecutable blocks with
2430 : undefined behavior that get diagnosed if they're left in the
2431 : IL because we've attached range information to new
2432 : SSA_NAMES. */
2433 9033918 : update_stmt_if_modified (stmt);
2434 9033918 : edge taken_edge = fold_cond (as_a <gcond *> (stmt));
2435 9033918 : if (taken_edge)
2436 : {
2437 101755 : gimple_set_modified (stmt, true);
2438 101755 : update_stmt (stmt);
2439 101755 : cfg_altered = true;
2440 101755 : return taken_edge;
2441 : }
2442 : }
2443 : }
2444 :
2445 54388950 : update_stmt_if_modified (stmt);
2446 54388950 : eliminate_redundant_computations (si, m_const_and_copies,
2447 : m_avail_exprs_stack);
2448 54388950 : stmt = gsi_stmt (*si);
2449 :
2450 : /* Perform simple redundant store elimination. */
2451 54388950 : if (gimple_assign_single_p (stmt)
2452 27554942 : && TREE_CODE (gimple_assign_lhs (stmt)) != SSA_NAME
2453 66912114 : && (TREE_CODE (gimple_assign_lhs (stmt)) != VAR_DECL
2454 1012112 : || !DECL_HARD_REGISTER (gimple_assign_lhs (stmt))))
2455 : {
2456 12521146 : tree lhs = gimple_assign_lhs (stmt);
2457 12521146 : tree rhs = gimple_assign_rhs1 (stmt);
2458 12521146 : tree cached_lhs;
2459 12521146 : gassign *new_stmt;
2460 12521146 : rhs = dom_valueize (rhs);
2461 : /* Build a new statement with the RHS and LHS exchanged. */
2462 12521146 : if (TREE_CODE (rhs) == SSA_NAME)
2463 : {
2464 5158948 : gimple *defstmt = SSA_NAME_DEF_STMT (rhs);
2465 5158948 : new_stmt = gimple_build_assign (rhs, lhs);
2466 5158948 : SSA_NAME_DEF_STMT (rhs) = defstmt;
2467 : }
2468 : else
2469 7362198 : new_stmt = gimple_build_assign (rhs, lhs);
2470 25042292 : gimple_set_vuse (new_stmt, gimple_vuse (stmt));
2471 12521146 : expr_hash_elt *elt = NULL;
2472 12521146 : cached_lhs = m_avail_exprs_stack->lookup_avail_expr (new_stmt, false,
2473 : false, &elt);
2474 12521146 : if (cached_lhs
2475 826522 : && operand_equal_p (rhs, cached_lhs, 0)
2476 12778694 : && refs_same_for_tbaa_p (elt->expr ()->kind == EXPR_SINGLE
2477 128774 : ? elt->expr ()->ops.single.rhs
2478 : : NULL_TREE, lhs))
2479 : {
2480 126047 : basic_block bb = gimple_bb (stmt);
2481 126047 : unlink_stmt_vdef (stmt);
2482 126047 : if (gsi_remove (si, true))
2483 : {
2484 0 : bitmap_set_bit (need_eh_cleanup, bb->index);
2485 0 : if (dump_file && (dump_flags & TDF_DETAILS))
2486 0 : fprintf (dump_file, " Flagged to clear EH edges.\n");
2487 : }
2488 126047 : release_defs (stmt);
2489 126047 : *removed_p = true;
2490 126047 : return retval;
2491 : }
2492 : }
2493 :
2494 : /* If this statement was not redundant, we may still be able to simplify
2495 : it, which may in turn allow other part of DOM or other passes to do
2496 : a better job. */
2497 54262903 : test_for_singularity (stmt, m_avail_exprs_stack);
2498 : }
2499 :
2500 : /* Record any additional equivalences created by this statement. */
2501 169600207 : if (is_gimple_assign (stmt))
2502 47448421 : record_equivalences_from_stmt (stmt, may_optimize_p, m_avail_exprs_stack);
2503 :
2504 : /* If STMT is a COND_EXPR or SWITCH_EXPR and it was modified, then we may
2505 : know where it goes. */
2506 339200414 : if (gimple_modified_p (stmt) || modified_p)
2507 : {
2508 4035390 : tree val = NULL;
2509 :
2510 4035390 : if (gimple_code (stmt) == GIMPLE_COND)
2511 445434 : val = fold_binary_loc (gimple_location (stmt),
2512 : gimple_cond_code (stmt), boolean_type_node,
2513 : gimple_cond_lhs (stmt),
2514 : gimple_cond_rhs (stmt));
2515 3589956 : else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt))
2516 2544 : val = gimple_switch_index (swtch_stmt);
2517 :
2518 447978 : if (val && TREE_CODE (val) == INTEGER_CST)
2519 : {
2520 61974 : retval = find_taken_edge (bb, val);
2521 61974 : if (retval)
2522 : {
2523 : /* Fix the condition to be either true or false. */
2524 61974 : if (gimple_code (stmt) == GIMPLE_COND)
2525 : {
2526 61959 : if (integer_zerop (val))
2527 32033 : gimple_cond_make_false (as_a <gcond *> (stmt));
2528 29926 : else if (integer_onep (val))
2529 29926 : gimple_cond_make_true (as_a <gcond *> (stmt));
2530 : else
2531 0 : gcc_unreachable ();
2532 :
2533 61959 : gimple_set_modified (stmt, true);
2534 : }
2535 :
2536 : /* Further simplifications may be possible. */
2537 61974 : cfg_altered = true;
2538 : }
2539 : }
2540 :
2541 4035390 : update_stmt_if_modified (stmt);
2542 :
2543 : /* If we simplified a statement in such a way as to be shown that it
2544 : cannot trap, update the eh information and the cfg to match. */
2545 4035390 : if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt))
2546 : {
2547 1498 : bitmap_set_bit (need_eh_cleanup, bb->index);
2548 1498 : if (dump_file && (dump_flags & TDF_DETAILS))
2549 0 : fprintf (dump_file, " Flagged to clear EH edges.\n");
2550 : }
2551 :
2552 4035390 : if (!was_noreturn
2553 4035390 : && is_gimple_call (stmt) && gimple_call_noreturn_p (stmt))
2554 3 : need_noreturn_fixup.safe_push (stmt);
2555 : }
2556 : return retval;
2557 : }
|
