Line data Source code
1 : /* Generic SSA value propagation engine.
2 : Copyright (C) 2004-2026 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 it
8 : under the terms of the GNU General Public License as published by the
9 : Free Software Foundation; either version 3, or (at your option) any
10 : later version.
11 :
12 : GCC is distributed in the hope that it will be useful, but WITHOUT
13 : ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 : FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 : 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 "ssa.h"
28 : #include "gimple-pretty-print.h"
29 : #include "dumpfile.h"
30 : #include "gimple-iterator.h"
31 : #include "gimple-fold.h"
32 : #include "tree-eh.h"
33 : #include "gimplify.h"
34 : #include "tree-cfg.h"
35 : #include "tree-ssa.h"
36 : #include "tree-ssa-propagate.h"
37 : #include "domwalk.h"
38 : #include "cfgloop.h"
39 : #include "tree-cfgcleanup.h"
40 : #include "cfganal.h"
41 : #include "tree-ssa-dce.h"
42 :
43 : /* This file implements a generic value propagation engine based on
44 : the same propagation used by the SSA-CCP algorithm [1].
45 :
46 : Propagation is performed by simulating the execution of every
47 : statement that produces the value being propagated. Simulation
48 : proceeds as follows:
49 :
50 : 1- Initially, all edges of the CFG are marked not executable and
51 : the CFG worklist is seeded with all the statements in the entry
52 : basic block (block 0).
53 :
54 : 2- Every statement S is simulated with a call to the call-back
55 : function SSA_PROP_VISIT_STMT. This evaluation may produce 3
56 : results:
57 :
58 : SSA_PROP_NOT_INTERESTING: Statement S produces nothing of
59 : interest and does not affect any of the work lists.
60 : The statement may be simulated again if any of its input
61 : operands change in future iterations of the simulator.
62 :
63 : SSA_PROP_VARYING: The value produced by S cannot be determined
64 : at compile time. Further simulation of S is not required.
65 : If S is a conditional jump, all the outgoing edges for the
66 : block are considered executable and added to the work
67 : list.
68 :
69 : SSA_PROP_INTERESTING: S produces a value that can be computed
70 : at compile time. Its result can be propagated into the
71 : statements that feed from S. Furthermore, if S is a
72 : conditional jump, only the edge known to be taken is added
73 : to the work list. Edges that are known not to execute are
74 : never simulated.
75 :
76 : 3- PHI nodes are simulated with a call to SSA_PROP_VISIT_PHI. The
77 : return value from SSA_PROP_VISIT_PHI has the same semantics as
78 : described in #2.
79 :
80 : 4- Three work lists are kept. Statements are only added to these
81 : lists if they produce one of SSA_PROP_INTERESTING or
82 : SSA_PROP_VARYING.
83 :
84 : CFG_BLOCKS contains the list of blocks to be simulated.
85 : Blocks are added to this list if their incoming edges are
86 : found executable.
87 :
88 : SSA_EDGE_WORKLIST contains the list of statements that we
89 : need to revisit.
90 :
91 : 5- Simulation terminates when all three work lists are drained.
92 :
93 : Before calling ssa_propagate, it is important to clear
94 : prop_simulate_again_p for all the statements in the program that
95 : should be simulated. This initialization allows an implementation
96 : to specify which statements should never be simulated.
97 :
98 : It is also important to compute def-use information before calling
99 : ssa_propagate.
100 :
101 : References:
102 :
103 : [1] Constant propagation with conditional branches,
104 : Wegman and Zadeck, ACM TOPLAS 13(2):181-210.
105 :
106 : [2] Building an Optimizing Compiler,
107 : Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9.
108 :
109 : [3] Advanced Compiler Design and Implementation,
110 : Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */
111 :
112 : /* Worklists of control flow edge destinations. This contains
113 : the CFG order number of the blocks so we can iterate in CFG
114 : order by visiting in bit-order. We use two worklists to
115 : first make forward progress before iterating. */
116 : static bitmap cfg_blocks;
117 : static int *bb_to_cfg_order;
118 : static int *cfg_order_to_bb;
119 :
120 : /* Worklists of SSA edges which will need reexamination as their
121 : definition has changed. SSA edges are def-use edges in the SSA
122 : web. For each D-U edge, we store the target statement or PHI node
123 : UID in a bitmap. UIDs order stmts in execution order. We use
124 : two worklists to first make forward progress before iterating. */
125 : static bitmap ssa_edge_worklist;
126 : static vec<gimple *> uid_to_stmt;
127 :
128 : /* Current RPO index in the iteration. */
129 : static int curr_order;
130 :
131 :
132 : /* We have just defined a new value for VAR. If IS_VARYING is true,
133 : add all immediate uses of VAR to VARYING_SSA_EDGES, otherwise add
134 : them to INTERESTING_SSA_EDGES. */
135 :
136 : static void
137 282464482 : add_ssa_edge (tree var)
138 : {
139 282464482 : imm_use_iterator iter;
140 282464482 : use_operand_p use_p;
141 :
142 1148680915 : FOR_EACH_IMM_USE_FAST (use_p, iter, var)
143 : {
144 583751951 : gimple *use_stmt = USE_STMT (use_p);
145 583751951 : if (!prop_simulate_again_p (use_stmt))
146 246405837 : continue;
147 :
148 : /* If we did not yet simulate the block wait for this to happen
149 : and do not add the stmt to the SSA edge worklist. */
150 337346114 : basic_block use_bb = gimple_bb (use_stmt);
151 337346114 : if (! (use_bb->flags & BB_VISITED))
152 137547979 : continue;
153 :
154 : /* If this is a use on a not yet executable edge do not bother to
155 : queue it. */
156 199798135 : if (gimple_code (use_stmt) == GIMPLE_PHI
157 199798135 : && !(EDGE_PRED (use_bb, PHI_ARG_INDEX_FROM_USE (use_p))->flags
158 64889234 : & EDGE_EXECUTABLE))
159 5845917 : continue;
160 :
161 193952218 : if (bitmap_set_bit (ssa_edge_worklist, gimple_uid (use_stmt)))
162 : {
163 179455222 : uid_to_stmt[gimple_uid (use_stmt)] = use_stmt;
164 179455222 : if (dump_file && (dump_flags & TDF_DETAILS))
165 : {
166 0 : fprintf (dump_file, "ssa_edge_worklist: adding SSA use in ");
167 0 : print_gimple_stmt (dump_file, use_stmt, 0, TDF_SLIM);
168 : }
169 : }
170 282464482 : }
171 282464482 : }
172 :
173 :
174 : /* Add edge E to the control flow worklist. */
175 :
176 : static void
177 135131209 : add_control_edge (edge e)
178 : {
179 135131209 : basic_block bb = e->dest;
180 135131209 : if (bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
181 : return;
182 :
183 : /* If the edge had already been executed, skip it. */
184 119777299 : if (e->flags & EDGE_EXECUTABLE)
185 : return;
186 :
187 103779187 : e->flags |= EDGE_EXECUTABLE;
188 :
189 103779187 : int bb_order = bb_to_cfg_order[bb->index];
190 103779187 : bitmap_set_bit (cfg_blocks, bb_order);
191 :
192 103779187 : if (dump_file && (dump_flags & TDF_DETAILS))
193 61 : fprintf (dump_file, "Adding destination of edge (%d -> %d) to worklist\n",
194 61 : e->src->index, e->dest->index);
195 : }
196 :
197 :
198 : /* Simulate the execution of STMT and update the work lists accordingly. */
199 :
200 : void
201 788137028 : ssa_propagation_engine::simulate_stmt (gimple *stmt)
202 : {
203 788137028 : enum ssa_prop_result val = SSA_PROP_NOT_INTERESTING;
204 788137028 : edge taken_edge = NULL;
205 788137028 : tree output_name = NULL_TREE;
206 :
207 : /* Pull the stmt off the SSA edge worklist. */
208 788137028 : bitmap_clear_bit (ssa_edge_worklist, gimple_uid (stmt));
209 :
210 : /* Don't bother visiting statements that are already
211 : considered varying by the propagator. */
212 788137028 : if (!prop_simulate_again_p (stmt))
213 554071728 : return;
214 :
215 354404707 : if (gimple_code (stmt) == GIMPLE_PHI)
216 : {
217 79204698 : val = visit_phi (as_a <gphi *> (stmt));
218 79204698 : output_name = gimple_phi_result (stmt);
219 : }
220 : else
221 275200009 : val = visit_stmt (stmt, &taken_edge, &output_name);
222 :
223 354404707 : if (val == SSA_PROP_VARYING)
224 : {
225 120339407 : prop_set_simulate_again (stmt, false);
226 :
227 : /* If the statement produced a new varying value, add the SSA
228 : edges coming out of OUTPUT_NAME. */
229 120339407 : if (output_name)
230 72024042 : add_ssa_edge (output_name);
231 :
232 : /* If STMT transfers control out of its basic block, add
233 : all outgoing edges to the work list. */
234 120339407 : if (stmt_ends_bb_p (stmt))
235 : {
236 49715998 : edge e;
237 49715998 : edge_iterator ei;
238 49715998 : basic_block bb = gimple_bb (stmt);
239 128214653 : FOR_EACH_EDGE (e, ei, bb->succs)
240 78498655 : add_control_edge (e);
241 : }
242 120339407 : return;
243 : }
244 234065300 : else if (val == SSA_PROP_INTERESTING)
245 : {
246 : /* If the statement produced new value, add the SSA edges coming
247 : out of OUTPUT_NAME. */
248 216978794 : if (output_name)
249 210440440 : add_ssa_edge (output_name);
250 :
251 : /* If we know which edge is going to be taken out of this block,
252 : add it to the CFG work list. */
253 216978794 : if (taken_edge)
254 6538354 : add_control_edge (taken_edge);
255 : }
256 :
257 : /* If there are no SSA uses on the stmt whose defs are simulated
258 : again then this stmt will be never visited again. */
259 234065300 : bool has_simulate_again_uses = false;
260 234065300 : use_operand_p use_p;
261 234065300 : ssa_op_iter iter;
262 234065300 : if (gimple_code (stmt) == GIMPLE_PHI)
263 : {
264 65990415 : edge_iterator ei;
265 65990415 : edge e;
266 65990415 : tree arg;
267 102692224 : FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->preds)
268 100817941 : if (!(e->flags & EDGE_EXECUTABLE)
269 100817941 : || ((arg = PHI_ARG_DEF_FROM_EDGE (stmt, e))
270 92735033 : && TREE_CODE (arg) == SSA_NAME
271 76112318 : && !SSA_NAME_IS_DEFAULT_DEF (arg)
272 75904616 : && prop_simulate_again_p (SSA_NAME_DEF_STMT (arg))))
273 : {
274 : has_simulate_again_uses = true;
275 : break;
276 : }
277 : }
278 : else
279 205967739 : FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
280 : {
281 166783765 : gimple *def_stmt = SSA_NAME_DEF_STMT (USE_FROM_PTR (use_p));
282 166783765 : if (!gimple_nop_p (def_stmt)
283 166783765 : && prop_simulate_again_p (def_stmt))
284 : {
285 : has_simulate_again_uses = true;
286 : break;
287 : }
288 : }
289 234065300 : if (!has_simulate_again_uses)
290 : {
291 41058257 : if (dump_file && (dump_flags & TDF_DETAILS))
292 40 : fprintf (dump_file, "marking stmt to be not simulated again\n");
293 41058257 : prop_set_simulate_again (stmt, false);
294 : }
295 : }
296 :
297 :
298 : /* Simulate the execution of BLOCK. Evaluate the statement associated
299 : with each variable reference inside the block. */
300 :
301 : void
302 79035005 : ssa_propagation_engine::simulate_block (basic_block block)
303 : {
304 79035005 : gimple_stmt_iterator gsi;
305 :
306 : /* There is nothing to do for the exit block. */
307 79035005 : if (block == EXIT_BLOCK_PTR_FOR_FN (cfun))
308 79035005 : return;
309 :
310 79035005 : if (dump_file && (dump_flags & TDF_DETAILS))
311 57 : fprintf (dump_file, "\nSimulating block %d\n", block->index);
312 :
313 : /* Always simulate PHI nodes, even if we have simulated this block
314 : before. */
315 120563026 : for (gsi = gsi_start_phis (block); !gsi_end_p (gsi); gsi_next (&gsi))
316 41528021 : simulate_stmt (gsi_stmt (gsi));
317 :
318 : /* If this is the first time we've simulated this block, then we
319 : must simulate each of its statements. */
320 79035005 : if (! (block->flags & BB_VISITED))
321 : {
322 73857251 : gimple_stmt_iterator j;
323 73857251 : unsigned int normal_edge_count;
324 73857251 : edge e, normal_edge;
325 73857251 : edge_iterator ei;
326 :
327 714975062 : for (j = gsi_start_bb (block); !gsi_end_p (j); gsi_next (&j))
328 567260560 : simulate_stmt (gsi_stmt (j));
329 :
330 : /* Note that we have simulated this block. */
331 73857251 : block->flags |= BB_VISITED;
332 :
333 : /* We cannot predict when abnormal and EH edges will be executed, so
334 : once a block is considered executable, we consider any
335 : outgoing abnormal edges as executable.
336 :
337 : TODO: This is not exactly true. Simplifying statement might
338 : prove it non-throwing and also computed goto can be handled
339 : when destination is known.
340 :
341 : At the same time, if this block has only one successor that is
342 : reached by non-abnormal edges, then add that successor to the
343 : worklist. */
344 73857251 : normal_edge_count = 0;
345 73857251 : normal_edge = NULL;
346 177905081 : FOR_EACH_EDGE (e, ei, block->succs)
347 : {
348 104047830 : if (e->flags & (EDGE_ABNORMAL | EDGE_EH))
349 6556566 : add_control_edge (e);
350 : else
351 : {
352 97491264 : normal_edge_count++;
353 97491264 : normal_edge = e;
354 : }
355 : }
356 :
357 73857251 : if (normal_edge_count == 1)
358 35693941 : add_control_edge (normal_edge);
359 : }
360 : }
361 :
362 :
363 : /* Initialize local data structures and work lists. */
364 :
365 : static void
366 7843693 : ssa_prop_init (void)
367 : {
368 7843693 : edge e;
369 7843693 : edge_iterator ei;
370 7843693 : basic_block bb;
371 :
372 : /* Worklists of SSA edges. */
373 7843693 : ssa_edge_worklist = BITMAP_ALLOC (NULL);
374 7843693 : bitmap_tree_view (ssa_edge_worklist);
375 :
376 : /* Worklist of basic-blocks. */
377 7843693 : bb_to_cfg_order = XNEWVEC (int, last_basic_block_for_fn (cfun) + 1);
378 7843693 : cfg_order_to_bb = XNEWVEC (int, n_basic_blocks_for_fn (cfun));
379 7843693 : int n = pre_and_rev_post_order_compute_fn (cfun, NULL,
380 : cfg_order_to_bb, false);
381 82259961 : for (int i = 0; i < n; ++i)
382 74416268 : bb_to_cfg_order[cfg_order_to_bb[i]] = i;
383 7843693 : cfg_blocks = BITMAP_ALLOC (NULL);
384 :
385 : /* Initially assume that every edge in the CFG is not executable.
386 : (including the edges coming out of the entry block). Mark blocks
387 : as not visited, blocks not yet visited will have all their statements
388 : simulated once an incoming edge gets executable. */
389 7843693 : set_gimple_stmt_max_uid (cfun, 0);
390 82259961 : for (int i = 0; i < n; ++i)
391 : {
392 74416268 : gimple_stmt_iterator si;
393 74416268 : bb = BASIC_BLOCK_FOR_FN (cfun, cfg_order_to_bb[i]);
394 :
395 104767756 : for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
396 : {
397 30351488 : gimple *stmt = gsi_stmt (si);
398 30351488 : gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
399 : }
400 :
401 718222993 : for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
402 : {
403 569390457 : gimple *stmt = gsi_stmt (si);
404 569390457 : gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
405 : }
406 :
407 74416268 : bb->flags &= ~BB_VISITED;
408 179026244 : FOR_EACH_EDGE (e, ei, bb->succs)
409 104609976 : e->flags &= ~EDGE_EXECUTABLE;
410 : }
411 7843693 : uid_to_stmt.safe_grow (gimple_stmt_max_uid (cfun), true);
412 7843693 : }
413 :
414 :
415 : /* Free allocated storage. */
416 :
417 : static void
418 7843693 : ssa_prop_fini (void)
419 : {
420 7843693 : BITMAP_FREE (cfg_blocks);
421 7843693 : free (bb_to_cfg_order);
422 7843693 : free (cfg_order_to_bb);
423 7843693 : BITMAP_FREE (ssa_edge_worklist);
424 7843693 : uid_to_stmt.release ();
425 7843693 : }
426 :
427 :
428 : /* Entry point to the propagation engine.
429 :
430 : The VISIT_STMT virtual function is called for every statement
431 : visited and the VISIT_PHI virtual function is called for every PHI
432 : node visited. */
433 :
434 : void
435 7843693 : ssa_propagation_engine::ssa_propagate (void)
436 : {
437 7843693 : ssa_prop_init ();
438 :
439 7843693 : curr_order = 0;
440 :
441 : /* Iterate until the worklists are empty. We iterate both blocks
442 : and stmts in RPO order, prioritizing backedge processing.
443 : Seed the algorithm by adding the successors of the entry block to the
444 : edge worklist. */
445 7843693 : edge e;
446 7843693 : edge_iterator ei;
447 15687386 : FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs)
448 : {
449 7843693 : e->flags &= ~EDGE_EXECUTABLE;
450 7843693 : add_control_edge (e);
451 : }
452 266227145 : while (1)
453 : {
454 266227145 : int next_block_order = (bitmap_empty_p (cfg_blocks)
455 266227145 : ? -1 : bitmap_first_set_bit (cfg_blocks));
456 266227145 : int next_stmt_uid = (bitmap_empty_p (ssa_edge_worklist)
457 266227145 : ? -1 : bitmap_first_set_bit (ssa_edge_worklist));
458 266227145 : if (next_block_order == -1 && next_stmt_uid == -1)
459 : break;
460 :
461 258383452 : int next_stmt_bb_order = -1;
462 258383452 : gimple *next_stmt = NULL;
463 258383452 : if (next_stmt_uid != -1)
464 : {
465 182929112 : next_stmt = uid_to_stmt[next_stmt_uid];
466 182929112 : next_stmt_bb_order = bb_to_cfg_order[gimple_bb (next_stmt)->index];
467 : }
468 :
469 : /* Pull the next block to simulate off the worklist if it comes first. */
470 258383452 : if (next_block_order != -1
471 228074260 : && (next_stmt_bb_order == -1
472 228074260 : || next_block_order <= next_stmt_bb_order))
473 : {
474 79035005 : curr_order = next_block_order;
475 79035005 : bitmap_clear_bit (cfg_blocks, next_block_order);
476 79035005 : basic_block bb
477 79035005 : = BASIC_BLOCK_FOR_FN (cfun, cfg_order_to_bb [next_block_order]);
478 79035005 : simulate_block (bb);
479 79035005 : }
480 : /* Else simulate from the SSA edge worklist. */
481 : else
482 : {
483 179348447 : curr_order = next_stmt_bb_order;
484 179348447 : if (dump_file && (dump_flags & TDF_DETAILS))
485 : {
486 0 : fprintf (dump_file, "\nSimulating statement: ");
487 0 : print_gimple_stmt (dump_file, next_stmt, 0, dump_flags);
488 : }
489 179348447 : simulate_stmt (next_stmt);
490 : }
491 : }
492 :
493 7843693 : ssa_prop_fini ();
494 7843693 : }
495 :
496 : /* Return true if STMT is of the form 'mem_ref = RHS', where 'mem_ref'
497 : is a non-volatile pointer dereference, a structure reference or a
498 : reference to a single _DECL. Ignore volatile memory references
499 : because they are not interesting for the optimizers. */
500 :
501 : bool
502 29560085 : stmt_makes_single_store (gimple *stmt)
503 : {
504 29560085 : tree lhs;
505 :
506 29560085 : if (gimple_code (stmt) != GIMPLE_ASSIGN
507 29560085 : && gimple_code (stmt) != GIMPLE_CALL)
508 : return false;
509 :
510 29574701 : if (!gimple_vdef (stmt))
511 : return false;
512 :
513 2496945 : lhs = gimple_get_lhs (stmt);
514 :
515 : /* A call statement may have a null LHS. */
516 2496945 : if (!lhs)
517 : return false;
518 :
519 2496945 : return (!TREE_THIS_VOLATILE (lhs)
520 2496945 : && (DECL_P (lhs)
521 2482329 : || REFERENCE_CLASS_P (lhs)));
522 : }
523 :
524 :
525 : /* Propagation statistics. */
526 : struct prop_stats_d
527 : {
528 : long num_const_prop;
529 : long num_copy_prop;
530 : long num_stmts_folded;
531 : };
532 :
533 : static struct prop_stats_d prop_stats;
534 :
535 : // range_query default methods to drive from a value_of_expr() ranther than
536 : // range_of_expr.
537 :
538 : tree
539 55852260 : substitute_and_fold_engine::value_on_edge (edge, tree expr)
540 : {
541 55852260 : return value_of_expr (expr);
542 : }
543 :
544 : tree
545 130985727 : substitute_and_fold_engine::value_of_stmt (gimple *stmt, tree name)
546 : {
547 130985727 : if (!name)
548 0 : name = gimple_get_lhs (stmt);
549 :
550 130985727 : gcc_checking_assert (!name || name == gimple_get_lhs (stmt));
551 :
552 130985727 : if (name)
553 130985727 : return value_of_expr (name);
554 : return NULL_TREE;
555 : }
556 :
557 : bool
558 0 : substitute_and_fold_engine::range_of_expr (vrange &, tree, gimple *)
559 : {
560 0 : return false;
561 : }
562 :
563 : /* Replace USE references in statement STMT with the values stored in
564 : PROP_VALUE. Return true if at least one reference was replaced. */
565 :
566 : bool
567 791880223 : substitute_and_fold_engine::replace_uses_in (gimple *stmt)
568 : {
569 791880223 : bool replaced = false;
570 791880223 : use_operand_p use;
571 791880223 : ssa_op_iter iter;
572 :
573 1168724078 : FOR_EACH_SSA_USE_OPERAND (use, stmt, iter, SSA_OP_USE)
574 : {
575 376843855 : tree tuse = USE_FROM_PTR (use);
576 376843855 : tree val = value_of_expr (tuse, stmt);
577 :
578 376843855 : if (val == tuse || val == NULL_TREE)
579 362768634 : continue;
580 :
581 14075221 : if (!may_propagate_copy (tuse, val))
582 512 : continue;
583 :
584 14074709 : if (TREE_CODE (val) != SSA_NAME)
585 5402620 : prop_stats.num_const_prop++;
586 : else
587 8672089 : prop_stats.num_copy_prop++;
588 :
589 14074709 : propagate_value (use, val);
590 :
591 14074709 : replaced = true;
592 : }
593 :
594 791880223 : return replaced;
595 : }
596 :
597 :
598 : /* Replace propagated values into all the arguments for PHI using the
599 : values from PROP_VALUE. */
600 :
601 : bool
602 23064458 : substitute_and_fold_engine::replace_phi_args_in (gphi *phi)
603 : {
604 23064458 : size_t i;
605 23064458 : bool replaced = false;
606 :
607 77705123 : for (i = 0; i < gimple_phi_num_args (phi); i++)
608 : {
609 54640665 : tree arg = gimple_phi_arg_def (phi, i);
610 :
611 54640665 : if (TREE_CODE (arg) == SSA_NAME)
612 : {
613 38509464 : edge e = gimple_phi_arg_edge (phi, i);
614 38509464 : tree val = value_on_edge (e, arg);
615 :
616 38509464 : if (val && val != arg && may_propagate_copy (arg, val))
617 : {
618 1123922 : if (TREE_CODE (val) != SSA_NAME)
619 30692 : prop_stats.num_const_prop++;
620 : else
621 1093230 : prop_stats.num_copy_prop++;
622 :
623 1123922 : propagate_value (PHI_ARG_DEF_PTR (phi, i), val);
624 1123922 : replaced = true;
625 :
626 : /* If we propagated a copy and this argument flows
627 : through an abnormal edge, update the replacement
628 : accordingly. */
629 1123922 : if (TREE_CODE (val) == SSA_NAME
630 1093230 : && e->flags & EDGE_ABNORMAL
631 1123922 : && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val))
632 : {
633 : /* This can only occur for virtual operands, since
634 : for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val))
635 : would prevent replacement. */
636 0 : gcc_checking_assert (virtual_operand_p (val));
637 0 : SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
638 : }
639 : }
640 : }
641 : }
642 :
643 23064458 : if (dump_file && (dump_flags & TDF_DETAILS))
644 : {
645 147 : if (!replaced)
646 147 : fprintf (dump_file, "No folding possible\n");
647 : else
648 : {
649 0 : fprintf (dump_file, "Folded into: ");
650 0 : print_gimple_stmt (dump_file, phi, 0, TDF_SLIM);
651 0 : fprintf (dump_file, "\n");
652 : }
653 : }
654 :
655 23064458 : return replaced;
656 : }
657 :
658 :
659 : class substitute_and_fold_dom_walker : public dom_walker
660 : {
661 : public:
662 12054539 : substitute_and_fold_dom_walker (cdi_direction direction,
663 : class substitute_and_fold_engine *engine)
664 12054539 : : dom_walker (direction),
665 12054539 : something_changed (false),
666 12054539 : substitute_and_fold_engine (engine)
667 : {
668 12054539 : dceworklist = BITMAP_ALLOC (NULL);
669 12054539 : stmts_to_fixup.create (0);
670 12054539 : need_eh_cleanup = BITMAP_ALLOC (NULL);
671 12054539 : need_ab_cleanup = BITMAP_ALLOC (NULL);
672 12054539 : }
673 12054539 : ~substitute_and_fold_dom_walker ()
674 12054539 : {
675 12054539 : BITMAP_FREE (dceworklist);
676 12054539 : stmts_to_fixup.release ();
677 12054539 : BITMAP_FREE (need_eh_cleanup);
678 12054539 : BITMAP_FREE (need_ab_cleanup);
679 12054539 : }
680 :
681 : edge before_dom_children (basic_block) final override;
682 118898282 : void after_dom_children (basic_block bb) final override
683 : {
684 118898282 : substitute_and_fold_engine->post_fold_bb (bb);
685 118898282 : }
686 :
687 : bool something_changed;
688 : bitmap dceworklist;
689 : vec<gimple *> stmts_to_fixup;
690 : bitmap need_eh_cleanup;
691 : bitmap need_ab_cleanup;
692 :
693 : class substitute_and_fold_engine *substitute_and_fold_engine;
694 :
695 : private:
696 : void foreach_new_stmt_in_bb (gimple_stmt_iterator old_gsi,
697 : gimple_stmt_iterator new_gsi);
698 : };
699 :
700 : /* Call post_new_stmt for each new statement that has been added
701 : to the current BB. OLD_GSI is the statement iterator before the BB
702 : changes ocurred. NEW_GSI is the iterator which may contain new
703 : statements. */
704 :
705 : void
706 14604505 : substitute_and_fold_dom_walker::foreach_new_stmt_in_bb
707 : (gimple_stmt_iterator old_gsi,
708 : gimple_stmt_iterator new_gsi)
709 : {
710 14604505 : basic_block bb = gsi_bb (new_gsi);
711 14604505 : if (gsi_end_p (old_gsi))
712 3262828 : old_gsi = gsi_start_bb (bb);
713 : else
714 12973091 : gsi_next (&old_gsi);
715 14672098 : while (gsi_stmt (old_gsi) != gsi_stmt (new_gsi))
716 : {
717 67593 : gimple *stmt = gsi_stmt (old_gsi);
718 67593 : substitute_and_fold_engine->post_new_stmt (stmt);
719 67593 : gsi_next (&old_gsi);
720 : }
721 14604505 : }
722 :
723 : bool
724 118898282 : substitute_and_fold_engine::propagate_into_phi_args (basic_block bb)
725 : {
726 118898282 : edge e;
727 118898282 : edge_iterator ei;
728 118898282 : bool propagated = false;
729 :
730 : /* Visit BB successor PHI nodes and replace PHI args. */
731 280917504 : FOR_EACH_EDGE (e, ei, bb->succs)
732 : {
733 162019222 : for (gphi_iterator gpi = gsi_start_phis (e->dest);
734 270236681 : !gsi_end_p (gpi); gsi_next (&gpi))
735 : {
736 108217459 : gphi *phi = gpi.phi ();
737 108217459 : use_operand_p use_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e);
738 108217459 : tree arg = USE_FROM_PTR (use_p);
739 174573753 : if (TREE_CODE (arg) != SSA_NAME
740 108217459 : || virtual_operand_p (arg))
741 66356294 : continue;
742 41861165 : tree val = value_on_edge (e, arg);
743 41861165 : if (val
744 3104331 : && is_gimple_min_invariant (val)
745 43790037 : && may_propagate_copy (arg, val))
746 : {
747 1926956 : propagate_value (use_p, val);
748 1926956 : propagated = true;
749 : }
750 : }
751 : }
752 118898282 : return propagated;
753 : }
754 :
755 : edge
756 118898282 : substitute_and_fold_dom_walker::before_dom_children (basic_block bb)
757 : {
758 118898282 : substitute_and_fold_engine->pre_fold_bb (bb);
759 :
760 : /* Propagate known values into PHI nodes. */
761 118898282 : for (gphi_iterator i = gsi_start_phis (bb);
762 163783929 : !gsi_end_p (i);
763 44885647 : gsi_next (&i))
764 : {
765 44885647 : gphi *phi = i.phi ();
766 44885647 : tree res = gimple_phi_result (phi);
767 89771294 : if (virtual_operand_p (res))
768 19962241 : continue;
769 24923406 : if (dump_file && (dump_flags & TDF_DETAILS))
770 : {
771 151 : fprintf (dump_file, "Folding PHI node: ");
772 151 : print_gimple_stmt (dump_file, phi, 0, TDF_SLIM);
773 : }
774 24923406 : if (res && TREE_CODE (res) == SSA_NAME)
775 : {
776 24923406 : tree sprime = substitute_and_fold_engine->value_of_expr (res, phi);
777 26782354 : if (sprime
778 24923406 : && sprime != res
779 24923406 : && may_propagate_copy (res, sprime))
780 : {
781 1858948 : if (dump_file && (dump_flags & TDF_DETAILS))
782 : {
783 4 : fprintf (dump_file, "Queued PHI for removal. Folds to: ");
784 4 : print_generic_expr (dump_file, sprime);
785 4 : fprintf (dump_file, "\n");
786 : }
787 1858948 : bitmap_set_bit (dceworklist, SSA_NAME_VERSION (res));
788 : /* As this now constitutes a copy duplicate points-to
789 : and range info appropriately. */
790 1858948 : if (TREE_CODE (sprime) == SSA_NAME)
791 1166175 : maybe_duplicate_ssa_info_at_copy (res, sprime);
792 1858948 : continue;
793 : }
794 : }
795 23064458 : something_changed |= substitute_and_fold_engine->replace_phi_args_in (phi);
796 : }
797 :
798 : /* Propagate known values into stmts. In some case it exposes
799 : more trivially deletable stmts to walk backward. */
800 237796564 : for (gimple_stmt_iterator i = gsi_start_bb (bb);
801 925522956 : !gsi_end_p (i);
802 806624674 : gsi_next (&i))
803 : {
804 806624674 : bool did_replace;
805 806624674 : gimple *stmt = gsi_stmt (i);
806 :
807 806624674 : substitute_and_fold_engine->pre_fold_stmt (stmt);
808 :
809 806624674 : if (dump_file && (dump_flags & TDF_DETAILS))
810 : {
811 1779 : fprintf (dump_file, "Folding statement: ");
812 1779 : print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
813 : }
814 :
815 : /* No point propagating into a stmt we have a value for we
816 : can propagate into all uses. Mark it for removal instead. */
817 806624674 : tree lhs = gimple_get_lhs (stmt);
818 806624674 : if (lhs && TREE_CODE (lhs) == SSA_NAME)
819 : {
820 178263681 : tree sprime = substitute_and_fold_engine->value_of_stmt (stmt, lhs);
821 193008132 : if (sprime
822 178263681 : && sprime != lhs
823 14763504 : && may_propagate_copy (lhs, sprime)
824 14762147 : && !stmt_could_throw_p (cfun, stmt)
825 193012377 : && !gimple_has_side_effects (stmt))
826 : {
827 14744451 : if (dump_file && (dump_flags & TDF_DETAILS))
828 : {
829 54 : fprintf (dump_file, "Queued stmt for removal. Folds to: ");
830 54 : print_generic_expr (dump_file, sprime);
831 54 : fprintf (dump_file, "\n");
832 : }
833 14744451 : bitmap_set_bit (dceworklist, SSA_NAME_VERSION (lhs));
834 : /* As this now constitutes a copy duplicate points-to
835 : and range info appropriately. */
836 14744451 : if (TREE_CODE (sprime) == SSA_NAME)
837 8733377 : maybe_duplicate_ssa_info_at_copy (lhs, sprime);
838 14744451 : continue;
839 : }
840 : }
841 :
842 : /* Replace the statement with its folded version and mark it
843 : folded. */
844 791880223 : did_replace = false;
845 791880223 : gimple *old_stmt = stmt;
846 791880223 : bool was_noreturn = false;
847 791880223 : bool can_make_abnormal_goto = false;
848 791880223 : if (is_gimple_call (stmt))
849 : {
850 52667254 : was_noreturn = gimple_call_noreturn_p (stmt);
851 52667254 : can_make_abnormal_goto = stmt_can_make_abnormal_goto (stmt);
852 : }
853 :
854 : /* Replace real uses in the statement. */
855 791880223 : did_replace |= substitute_and_fold_engine->replace_uses_in (stmt);
856 :
857 791880223 : gimple_stmt_iterator prev_gsi = i;
858 791880223 : gsi_prev (&prev_gsi);
859 :
860 : /* If we made a replacement, fold the statement. */
861 791880223 : if (did_replace)
862 : {
863 13242774 : fold_stmt (&i, follow_single_use_edges);
864 13242774 : stmt = gsi_stmt (i);
865 13242774 : gimple_set_modified (stmt, true);
866 : }
867 : /* Also fold if we want to fold all statements. */
868 778637449 : else if (substitute_and_fold_engine->fold_all_stmts
869 778637449 : && fold_stmt (&i, follow_single_use_edges))
870 : {
871 0 : did_replace = true;
872 0 : stmt = gsi_stmt (i);
873 0 : gimple_set_modified (stmt, true);
874 : }
875 :
876 : /* Some statements may be simplified using propagator
877 : specific information. Do this before propagating
878 : into the stmt to not disturb pass specific information. */
879 791880223 : update_stmt_if_modified (stmt);
880 791880223 : if (substitute_and_fold_engine->fold_stmt (&i))
881 : {
882 1765859 : did_replace = true;
883 1765859 : prop_stats.num_stmts_folded++;
884 1765859 : stmt = gsi_stmt (i);
885 1765859 : gimple_set_modified (stmt, true);
886 : }
887 :
888 : /* If this is a control statement the propagator left edges
889 : unexecuted on force the condition in a way consistent with
890 : that. See PR66945 for cases where the propagator can end
891 : up with a different idea of a taken edge than folding
892 : (once undefined behavior is involved). */
893 791880223 : if (gimple_code (stmt) == GIMPLE_COND)
894 : {
895 42631832 : if ((EDGE_SUCC (bb, 0)->flags & EDGE_EXECUTABLE)
896 42631832 : ^ (EDGE_SUCC (bb, 1)->flags & EDGE_EXECUTABLE))
897 : {
898 434050 : if (((EDGE_SUCC (bb, 0)->flags & EDGE_TRUE_VALUE) != 0)
899 434050 : == ((EDGE_SUCC (bb, 0)->flags & EDGE_EXECUTABLE) != 0))
900 102484 : gimple_cond_make_true (as_a <gcond *> (stmt));
901 : else
902 331566 : gimple_cond_make_false (as_a <gcond *> (stmt));
903 434050 : gimple_set_modified (stmt, true);
904 434050 : did_replace = true;
905 : }
906 : }
907 :
908 : /* Now cleanup. */
909 791880223 : if (did_replace)
910 : {
911 14604505 : foreach_new_stmt_in_bb (prev_gsi, i);
912 :
913 : /* If we cleaned up EH information from the statement,
914 : remove EH edges. */
915 14604505 : if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt))
916 155774 : bitmap_set_bit (need_eh_cleanup, bb->index);
917 :
918 : /* If we turned a call with possible abnormal control transfer
919 : into one that doesn't, remove abnormal edges. */
920 14604505 : if (can_make_abnormal_goto
921 14604505 : && !stmt_can_make_abnormal_goto (stmt))
922 3 : bitmap_set_bit (need_ab_cleanup, bb->index);
923 :
924 : /* If we turned a not noreturn call into a noreturn one
925 : schedule it for fixup. */
926 14604505 : if (!was_noreturn
927 14474515 : && is_gimple_call (stmt)
928 16015813 : && gimple_call_noreturn_p (stmt))
929 70 : stmts_to_fixup.safe_push (stmt);
930 :
931 14604505 : if (gimple_assign_single_p (stmt))
932 : {
933 3458310 : tree rhs = gimple_assign_rhs1 (stmt);
934 :
935 3458310 : if (TREE_CODE (rhs) == ADDR_EXPR)
936 374759 : recompute_tree_invariant_for_addr_expr (rhs);
937 : }
938 :
939 : /* Determine what needs to be done to update the SSA form. */
940 14604505 : update_stmt_if_modified (stmt);
941 14604505 : if (!is_gimple_debug (stmt))
942 10567033 : something_changed = true;
943 : }
944 :
945 791880223 : if (dump_file && (dump_flags & TDF_DETAILS))
946 : {
947 1725 : if (did_replace)
948 : {
949 141 : fprintf (dump_file, "Folded into: ");
950 141 : print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
951 141 : fprintf (dump_file, "\n");
952 : }
953 : else
954 1584 : fprintf (dump_file, "Not folded\n");
955 : }
956 : }
957 :
958 118898282 : something_changed |= substitute_and_fold_engine->propagate_into_phi_args (bb);
959 :
960 118898282 : return NULL;
961 : }
962 :
963 :
964 :
965 : /* Perform final substitution and folding of propagated values.
966 : Process the whole function if BLOCK is null, otherwise only
967 : process the blocks that BLOCK dominates. In the latter case,
968 : it is the caller's responsibility to ensure that dominator
969 : information is available and up-to-date.
970 :
971 : PROP_VALUE[I] contains the single value that should be substituted
972 : at every use of SSA name N_I. If PROP_VALUE is NULL, no values are
973 : substituted.
974 :
975 : If FOLD_FN is non-NULL the function will be invoked on all statements
976 : before propagating values for pass specific simplification.
977 :
978 : DO_DCE is true if trivially dead stmts can be removed.
979 :
980 : If DO_DCE is true, the statements within a BB are walked from
981 : last to first element. Otherwise we scan from first to last element.
982 :
983 : Return TRUE when something changed. */
984 :
985 : bool
986 12054539 : substitute_and_fold_engine::substitute_and_fold (basic_block block)
987 : {
988 12054539 : if (dump_file && (dump_flags & TDF_DETAILS))
989 158 : fprintf (dump_file, "\nSubstituting values and folding statements\n\n");
990 :
991 12054539 : memset (&prop_stats, 0, sizeof (prop_stats));
992 :
993 : /* Don't call calculate_dominance_info when iterating over a subgraph.
994 : Callers that are using the interface this way are likely to want to
995 : iterate over several disjoint subgraphs, and it would be expensive
996 : in enable-checking builds to revalidate the whole dominance tree
997 : each time. */
998 12054539 : if (block)
999 1192 : gcc_assert (dom_info_state (CDI_DOMINATORS));
1000 : else
1001 12053347 : calculate_dominance_info (CDI_DOMINATORS);
1002 12054539 : substitute_and_fold_dom_walker walker (CDI_DOMINATORS, this);
1003 12054539 : walker.walk (block ? block : ENTRY_BLOCK_PTR_FOR_FN (cfun));
1004 :
1005 12054539 : simple_dce_from_worklist (walker.dceworklist, walker.need_eh_cleanup);
1006 12054539 : if (!bitmap_empty_p (walker.need_eh_cleanup))
1007 36739 : gimple_purge_all_dead_eh_edges (walker.need_eh_cleanup);
1008 12054539 : if (!bitmap_empty_p (walker.need_ab_cleanup))
1009 3 : gimple_purge_all_dead_abnormal_call_edges (walker.need_ab_cleanup);
1010 :
1011 : /* Fixup stmts that became noreturn calls. This may require splitting
1012 : blocks and thus isn't possible during the dominator walk. Do this
1013 : in reverse order so we don't inadvertedly remove a stmt we want to
1014 : fixup by visiting a dominating now noreturn call first. */
1015 12054609 : while (!walker.stmts_to_fixup.is_empty ())
1016 : {
1017 70 : gimple *stmt = walker.stmts_to_fixup.pop ();
1018 76 : if (!gimple_bb (stmt))
1019 6 : continue;
1020 64 : if (dump_file && dump_flags & TDF_DETAILS)
1021 : {
1022 0 : fprintf (dump_file, "Fixing up noreturn call ");
1023 0 : print_gimple_stmt (dump_file, stmt, 0);
1024 0 : fprintf (dump_file, "\n");
1025 : }
1026 64 : fixup_noreturn_call (stmt);
1027 : }
1028 :
1029 12054539 : statistics_counter_event (cfun, "Constants propagated",
1030 12054539 : prop_stats.num_const_prop);
1031 12054539 : statistics_counter_event (cfun, "Copies propagated",
1032 12054539 : prop_stats.num_copy_prop);
1033 12054539 : statistics_counter_event (cfun, "Statements folded",
1034 12054539 : prop_stats.num_stmts_folded);
1035 :
1036 12054539 : return walker.something_changed;
1037 12054539 : }
1038 :
1039 :
1040 : /* Return true if we may propagate ORIG into DEST, false otherwise.
1041 : If DEST_NOT_ABNORMAL_PHI_EDGE_P is true then assume the propagation does
1042 : not happen into a PHI argument which flows in from an abnormal edge
1043 : which relaxes some constraints. */
1044 :
1045 : bool
1046 150033516 : may_propagate_copy (tree dest, tree orig, bool dest_not_abnormal_phi_edge_p)
1047 : {
1048 150033516 : tree type_d = TREE_TYPE (dest);
1049 150033516 : tree type_o = TREE_TYPE (orig);
1050 :
1051 : /* If ORIG is a default definition which flows in from an abnormal edge
1052 : then the copy can be propagated. It is important that we do so to avoid
1053 : uninitialized copies. */
1054 150033516 : if (TREE_CODE (orig) == SSA_NAME
1055 104029919 : && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig)
1056 28977 : && SSA_NAME_IS_DEFAULT_DEF (orig)
1057 150036756 : && (SSA_NAME_VAR (orig) == NULL_TREE
1058 3240 : || VAR_P (SSA_NAME_VAR (orig))))
1059 : ;
1060 : /* Otherwise if ORIG just flows in from an abnormal edge then the copy cannot
1061 : be propagated. */
1062 150030679 : else if (TREE_CODE (orig) == SSA_NAME
1063 150030679 : && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig))
1064 : return false;
1065 : /* Similarly if DEST flows in from an abnormal edge then the copy cannot be
1066 : propagated. If we know we do not propagate into such a PHI argument this
1067 : does not apply. */
1068 150004539 : else if (!dest_not_abnormal_phi_edge_p
1069 77450589 : && TREE_CODE (dest) == SSA_NAME
1070 227455128 : && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (dest))
1071 : return false;
1072 :
1073 : /* Do not copy between types for which we *do* need a conversion. */
1074 149992137 : if (!useless_type_conversion_p (type_d, type_o))
1075 : return false;
1076 :
1077 : /* Generally propagating virtual operands is not ok as that may
1078 : create overlapping life-ranges. */
1079 149975790 : if (TREE_CODE (dest) == SSA_NAME && virtual_operand_p (dest))
1080 : return false;
1081 :
1082 : /* Keep lhs of [[gnu::musttail]] calls as is, those need to be still
1083 : tail callable. */
1084 149535695 : if (TREE_CODE (dest) == SSA_NAME
1085 149363646 : && is_gimple_call (SSA_NAME_DEF_STMT (dest))
1086 150887057 : && gimple_call_must_tail_p (as_a <gcall *> (SSA_NAME_DEF_STMT (dest))))
1087 : return false;
1088 :
1089 : /* Anything else is OK. */
1090 : return true;
1091 : }
1092 :
1093 : /* Like may_propagate_copy, but use as the destination expression
1094 : the principal expression (typically, the RHS) contained in
1095 : statement DEST. This is more efficient when working with the
1096 : gimple tuples representation. */
1097 :
1098 : bool
1099 381883 : may_propagate_copy_into_stmt (gimple *dest, tree orig)
1100 : {
1101 381883 : tree type_d;
1102 381883 : tree type_o;
1103 :
1104 : /* If the statement is a switch or a single-rhs assignment,
1105 : then the expression to be replaced by the propagation may
1106 : be an SSA_NAME. Fortunately, there is an explicit tree
1107 : for the expression, so we delegate to may_propagate_copy. */
1108 :
1109 381883 : if (gimple_assign_single_p (dest))
1110 186974 : return may_propagate_copy (gimple_assign_rhs1 (dest), orig, true);
1111 194909 : else if (gswitch *dest_swtch = dyn_cast <gswitch *> (dest))
1112 0 : return may_propagate_copy (gimple_switch_index (dest_swtch), orig, true);
1113 :
1114 : /* In other cases, the expression is not materialized, so there
1115 : is no destination to pass to may_propagate_copy. On the other
1116 : hand, the expression cannot be an SSA_NAME, so the analysis
1117 : is much simpler. */
1118 :
1119 194909 : if (TREE_CODE (orig) == SSA_NAME
1120 194909 : && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig))
1121 : return false;
1122 :
1123 194909 : if (is_gimple_assign (dest))
1124 164231 : type_d = TREE_TYPE (gimple_assign_lhs (dest));
1125 30678 : else if (gimple_code (dest) == GIMPLE_COND)
1126 25772 : type_d = boolean_type_node;
1127 4906 : else if (is_gimple_call (dest)
1128 4906 : && gimple_call_lhs (dest) != NULL_TREE)
1129 4906 : type_d = TREE_TYPE (gimple_call_lhs (dest));
1130 : else
1131 0 : gcc_unreachable ();
1132 :
1133 194909 : type_o = TREE_TYPE (orig);
1134 :
1135 194909 : if (!useless_type_conversion_p (type_d, type_o))
1136 : return false;
1137 :
1138 : return true;
1139 : }
1140 :
1141 : /* Replace *OP_P with value VAL (assumed to be a constant or another SSA_NAME).
1142 :
1143 : Use this version when not const/copy propagating values. For example,
1144 : PRE uses this version when building expressions as they would appear
1145 : in specific blocks taking into account actions of PHI nodes.
1146 :
1147 : The statement in which an expression has been replaced should be
1148 : folded using fold_stmt_inplace. */
1149 :
1150 : void
1151 54231919 : replace_exp (use_operand_p op_p, tree val)
1152 : {
1153 54231919 : if (TREE_CODE (val) == SSA_NAME || CONSTANT_CLASS_P (val))
1154 50461815 : SET_USE (op_p, val);
1155 : else
1156 3770104 : SET_USE (op_p, unshare_expr (val));
1157 54231919 : }
1158 :
1159 :
1160 : /* Propagate the value VAL (assumed to be a constant or another SSA_NAME)
1161 : into the operand pointed to by OP_P.
1162 :
1163 : Use this version for const/copy propagation as it will perform additional
1164 : checks to ensure validity of the const/copy propagation. */
1165 :
1166 : void
1167 47997329 : propagate_value (use_operand_p op_p, tree val)
1168 : {
1169 47997329 : if (flag_checking)
1170 : {
1171 47996859 : bool ab = (is_a <gphi *> (USE_STMT (op_p))
1172 64060127 : && (gimple_phi_arg_edge (as_a <gphi *> (USE_STMT (op_p)),
1173 16063268 : PHI_ARG_INDEX_FROM_USE (op_p))
1174 16063268 : ->flags & EDGE_ABNORMAL));
1175 47996859 : gcc_assert (may_propagate_copy (USE_FROM_PTR (op_p), val, !ab));
1176 : }
1177 47997329 : replace_exp (op_p, val);
1178 47997329 : }
1179 :
1180 :
1181 : /* Propagate the value VAL (assumed to be a constant or another SSA_NAME)
1182 : into the tree pointed to by OP_P.
1183 :
1184 : Use this version for const/copy propagation when SSA operands are not
1185 : available. It will perform the additional checks to ensure validity of
1186 : the const/copy propagation, but will not update any operand information.
1187 : Be sure to mark the stmt as modified. */
1188 :
1189 : void
1190 407999 : propagate_tree_value (tree *op_p, tree val)
1191 : {
1192 407999 : if (TREE_CODE (val) == SSA_NAME)
1193 366959 : *op_p = val;
1194 : else
1195 41040 : *op_p = unshare_expr (val);
1196 407999 : }
1197 :
1198 :
1199 : /* Like propagate_tree_value, but use as the operand to replace
1200 : the principal expression (typically, the RHS) contained in the
1201 : statement referenced by iterator GSI. Note that it is not
1202 : always possible to update the statement in-place, so a new
1203 : statement may be created to replace the original. */
1204 :
1205 : void
1206 407999 : propagate_tree_value_into_stmt (gimple_stmt_iterator *gsi, tree val)
1207 : {
1208 407999 : gimple *stmt = gsi_stmt (*gsi);
1209 :
1210 407999 : if (is_gimple_assign (stmt))
1211 : {
1212 372061 : tree expr = NULL_TREE;
1213 372061 : if (gimple_assign_single_p (stmt))
1214 204088 : expr = gimple_assign_rhs1 (stmt);
1215 372061 : propagate_tree_value (&expr, val);
1216 372061 : gimple_assign_set_rhs_from_tree (gsi, expr);
1217 : }
1218 35938 : else if (gcond *cond_stmt = dyn_cast <gcond *> (stmt))
1219 : {
1220 28973 : tree lhs = NULL_TREE;
1221 28973 : tree rhs = build_zero_cst (TREE_TYPE (val));
1222 28973 : propagate_tree_value (&lhs, val);
1223 28973 : gimple_cond_set_code (cond_stmt, NE_EXPR);
1224 28973 : gimple_cond_set_lhs (cond_stmt, lhs);
1225 28973 : gimple_cond_set_rhs (cond_stmt, rhs);
1226 : }
1227 6965 : else if (is_gimple_call (stmt)
1228 6965 : && gimple_call_lhs (stmt) != NULL_TREE)
1229 : {
1230 6965 : tree expr = NULL_TREE;
1231 6965 : propagate_tree_value (&expr, val);
1232 6965 : replace_call_with_value (gsi, expr);
1233 : }
1234 0 : else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt))
1235 0 : propagate_tree_value (gimple_switch_index_ptr (swtch_stmt), val);
1236 : else
1237 0 : gcc_unreachable ();
1238 407999 : }
1239 :
1240 : /* Check exits of each loop in FUN, walk over loop closed PHIs in
1241 : each exit basic block and propagate degenerate PHIs. */
1242 :
1243 : unsigned
1244 240832 : clean_up_loop_closed_phi (function *fun)
1245 : {
1246 240832 : gphi *phi;
1247 240832 : tree rhs;
1248 240832 : tree lhs;
1249 240832 : gphi_iterator gsi;
1250 :
1251 : /* Avoid possibly quadratic work when scanning for loop exits across
1252 : all loops of a nest. */
1253 240832 : if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
1254 : return 0;
1255 :
1256 : /* replace_uses_by might purge dead EH edges and we want it to also
1257 : remove dominated blocks. */
1258 240832 : calculate_dominance_info (CDI_DOMINATORS);
1259 :
1260 : /* Walk over loop in function. */
1261 1352388 : for (auto loop : loops_list (fun, 0))
1262 : {
1263 : /* Check each exit edege of loop. */
1264 629892 : auto_vec<edge> exits = get_loop_exit_edges (loop);
1265 3019410 : for (edge e : exits)
1266 1908830 : if (single_pred_p (e->dest))
1267 : /* Walk over loop-closed PHIs. */
1268 1664671 : for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi);)
1269 : {
1270 898215 : phi = gsi.phi ();
1271 898215 : rhs = gimple_phi_arg_def (phi, 0);
1272 898215 : lhs = gimple_phi_result (phi);
1273 :
1274 1795540 : if (virtual_operand_p (rhs))
1275 : {
1276 476536 : imm_use_iterator iter;
1277 476536 : use_operand_p use_p;
1278 476536 : gimple *stmt;
1279 :
1280 1633917 : FOR_EACH_IMM_USE_STMT (stmt, iter, lhs)
1281 2056331 : FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
1282 687743 : SET_USE (use_p, rhs);
1283 :
1284 476536 : if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
1285 48 : SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs) = 1;
1286 476536 : remove_phi_node (&gsi, true);
1287 : }
1288 421679 : else if (may_propagate_copy (lhs, rhs))
1289 : {
1290 : /* Dump details. */
1291 421638 : if (dump_file && (dump_flags & TDF_DETAILS))
1292 : {
1293 3 : fprintf (dump_file, " Replacing '");
1294 3 : print_generic_expr (dump_file, lhs, dump_flags);
1295 3 : fprintf (dump_file, "' with '");
1296 3 : print_generic_expr (dump_file, rhs, dump_flags);
1297 3 : fprintf (dump_file, "'\n");
1298 : }
1299 :
1300 421638 : replace_uses_by (lhs, rhs);
1301 421638 : remove_phi_node (&gsi, true);
1302 : }
1303 : else
1304 41 : gsi_next (&gsi);
1305 : }
1306 629892 : }
1307 :
1308 240832 : return 0;
1309 : }
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