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1 : : /* Global constant/copy propagation for RTL.
2 : : Copyright (C) 1997-2025 Free Software Foundation, Inc.
3 : :
4 : : This file is part of GCC.
5 : :
6 : : GCC is free software; you can redistribute it and/or modify it under
7 : : the terms of the GNU General Public License as published by the Free
8 : : Software Foundation; either version 3, or (at your option) any later
9 : : version.
10 : :
11 : : GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 : : WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 : : FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 : : for more details.
15 : :
16 : : You should have received a copy of the GNU General Public License
17 : : along with GCC; see the file COPYING3. If not see
18 : : <http://www.gnu.org/licenses/>. */
19 : :
20 : : #include "config.h"
21 : : #include "system.h"
22 : : #include "coretypes.h"
23 : : #include "backend.h"
24 : : #include "rtl.h"
25 : : #include "rtlanal.h"
26 : : #include "cfghooks.h"
27 : : #include "df.h"
28 : : #include "insn-config.h"
29 : : #include "memmodel.h"
30 : : #include "emit-rtl.h"
31 : : #include "recog.h"
32 : : #include "diagnostic-core.h"
33 : : #include "toplev.h"
34 : : #include "cfgrtl.h"
35 : : #include "cfganal.h"
36 : : #include "lcm.h"
37 : : #include "cfgcleanup.h"
38 : : #include "cselib.h"
39 : : #include "intl.h"
40 : : #include "tree-pass.h"
41 : : #include "dbgcnt.h"
42 : : #include "cfgloop.h"
43 : : #include "gcse.h"
44 : :
45 : :
46 : : /* An obstack for our working variables. */
47 : : static struct obstack cprop_obstack;
48 : :
49 : : /* Occurrence of an expression.
50 : : There is one per basic block. If a pattern appears more than once the
51 : : last appearance is used. */
52 : :
53 : : struct cprop_occr
54 : : {
55 : : /* Next occurrence of this expression. */
56 : : struct cprop_occr *next;
57 : : /* The insn that computes the expression. */
58 : : rtx_insn *insn;
59 : : };
60 : :
61 : : /* Hash table entry for assignment expressions. */
62 : :
63 : : struct cprop_expr
64 : : {
65 : : /* The expression (DEST := SRC). */
66 : : rtx dest;
67 : : rtx src;
68 : :
69 : : /* Index in the available expression bitmaps. */
70 : : int bitmap_index;
71 : : /* Next entry with the same hash. */
72 : : struct cprop_expr *next_same_hash;
73 : : /* List of available occurrence in basic blocks in the function.
74 : : An "available occurrence" is one that is the last occurrence in the
75 : : basic block and whose operands are not modified by following statements
76 : : in the basic block [including this insn]. */
77 : : struct cprop_occr *avail_occr;
78 : : };
79 : :
80 : : /* Hash table for copy propagation expressions.
81 : : Each hash table is an array of buckets.
82 : : ??? It is known that if it were an array of entries, structure elements
83 : : `next_same_hash' and `bitmap_index' wouldn't be necessary. However, it is
84 : : not clear whether in the final analysis a sufficient amount of memory would
85 : : be saved as the size of the available expression bitmaps would be larger
86 : : [one could build a mapping table without holes afterwards though].
87 : : Someday I'll perform the computation and figure it out. */
88 : :
89 : : struct hash_table_d
90 : : {
91 : : /* The table itself.
92 : : This is an array of `set_hash_table_size' elements. */
93 : : struct cprop_expr **table;
94 : :
95 : : /* Size of the hash table, in elements. */
96 : : unsigned int size;
97 : :
98 : : /* Number of hash table elements. */
99 : : unsigned int n_elems;
100 : : };
101 : :
102 : : /* Copy propagation hash table. */
103 : : static struct hash_table_d set_hash_table;
104 : :
105 : : /* Array of implicit set patterns indexed by basic block index. */
106 : : static rtx *implicit_sets;
107 : :
108 : : /* Array of indexes of expressions for implicit set patterns indexed by basic
109 : : block index. In other words, implicit_set_indexes[i] is the bitmap_index
110 : : of the expression whose RTX is implicit_sets[i]. */
111 : : static int *implicit_set_indexes;
112 : :
113 : : /* Bitmap containing one bit for each register in the program.
114 : : Used when performing GCSE to track which registers have been set since
115 : : the start or end of the basic block while traversing that block. */
116 : : static regset reg_set_bitmap;
117 : :
118 : : /* Various variables for statistics gathering. */
119 : :
120 : : /* Memory used in a pass.
121 : : This isn't intended to be absolutely precise. Its intent is only
122 : : to keep an eye on memory usage. */
123 : : static int bytes_used;
124 : :
125 : : /* Number of local constants propagated. */
126 : : static int local_const_prop_count;
127 : : /* Number of local copies propagated. */
128 : : static int local_copy_prop_count;
129 : : /* Number of global constants propagated. */
130 : : static int global_const_prop_count;
131 : : /* Number of global copies propagated. */
132 : : static int global_copy_prop_count;
133 : :
134 : : #define GOBNEW(T) ((T *) cprop_alloc (sizeof (T)))
135 : : #define GOBNEWVAR(T, S) ((T *) cprop_alloc ((S)))
136 : :
137 : : /* Cover function to obstack_alloc. */
138 : :
139 : : static void *
140 : 28824170 : cprop_alloc (unsigned long size)
141 : : {
142 : 28824170 : bytes_used += size;
143 : 28824170 : return obstack_alloc (&cprop_obstack, size);
144 : : }
145 : :
146 : : /* Return true if register X is unchanged from INSN to the end
147 : : of INSN's basic block. */
148 : :
149 : : static bool
150 : 65132111 : reg_available_p (const_rtx x, const rtx_insn *insn ATTRIBUTE_UNUSED)
151 : : {
152 : 2399686 : return ! REGNO_REG_SET_P (reg_set_bitmap, REGNO (x));
153 : : }
154 : :
155 : : /* Hash a set of register REGNO.
156 : :
157 : : Sets are hashed on the register that is set. This simplifies the PRE copy
158 : : propagation code.
159 : :
160 : : ??? May need to make things more elaborate. Later, as necessary. */
161 : :
162 : : static unsigned int
163 : 101178896 : hash_mod (int regno, int hash_table_size)
164 : : {
165 : 101178896 : return (unsigned) regno % hash_table_size;
166 : : }
167 : :
168 : : /* Insert assignment DEST:=SET from INSN in the hash table.
169 : : DEST is a register and SET is a register or a suitable constant.
170 : : If the assignment is already present in the table, record it as
171 : : the last occurrence in INSN's basic block.
172 : : IMPLICIT is true if it's an implicit set, false otherwise. */
173 : :
174 : : static void
175 : 15363867 : insert_set_in_table (rtx dest, rtx src, rtx_insn *insn,
176 : : struct hash_table_d *table, bool implicit)
177 : : {
178 : 15363867 : bool found = false;
179 : 15363867 : unsigned int hash;
180 : 15363867 : struct cprop_expr *cur_expr, *last_expr = NULL;
181 : 15363867 : struct cprop_occr *cur_occr;
182 : :
183 : 15363867 : hash = hash_mod (REGNO (dest), table->size);
184 : :
185 : 38732498 : for (cur_expr = table->table[hash]; cur_expr;
186 : 23368631 : cur_expr = cur_expr->next_same_hash)
187 : : {
188 : 25272195 : if (dest == cur_expr->dest
189 : 24786739 : && src == cur_expr->src)
190 : : {
191 : : found = true;
192 : : break;
193 : : }
194 : 23368631 : last_expr = cur_expr;
195 : : }
196 : :
197 : 15363867 : if (! found)
198 : : {
199 : 13460303 : cur_expr = GOBNEW (struct cprop_expr);
200 : 13460303 : bytes_used += sizeof (struct cprop_expr);
201 : 13460303 : if (table->table[hash] == NULL)
202 : : /* This is the first pattern that hashed to this index. */
203 : 10787346 : table->table[hash] = cur_expr;
204 : : else
205 : : /* Add EXPR to end of this hash chain. */
206 : 2672957 : last_expr->next_same_hash = cur_expr;
207 : :
208 : : /* Set the fields of the expr element.
209 : : We must copy X because it can be modified when copy propagation is
210 : : performed on its operands. */
211 : 13460303 : cur_expr->dest = copy_rtx (dest);
212 : 13460303 : cur_expr->src = copy_rtx (src);
213 : 13460303 : cur_expr->bitmap_index = table->n_elems++;
214 : 13460303 : cur_expr->next_same_hash = NULL;
215 : 13460303 : cur_expr->avail_occr = NULL;
216 : : }
217 : :
218 : : /* Now record the occurrence. */
219 : 15363867 : cur_occr = cur_expr->avail_occr;
220 : :
221 : 15363867 : if (cur_occr
222 : 15363867 : && BLOCK_FOR_INSN (cur_occr->insn) == BLOCK_FOR_INSN (insn))
223 : : {
224 : : /* Found another instance of the expression in the same basic block.
225 : : Prefer this occurrence to the currently recorded one. We want
226 : : the last one in the block and the block is scanned from start
227 : : to end. */
228 : 0 : cur_occr->insn = insn;
229 : : }
230 : : else
231 : : {
232 : : /* First occurrence of this expression in this basic block. */
233 : 15363867 : cur_occr = GOBNEW (struct cprop_occr);
234 : 15363867 : bytes_used += sizeof (struct cprop_occr);
235 : 15363867 : cur_occr->insn = insn;
236 : 15363867 : cur_occr->next = cur_expr->avail_occr;
237 : 15363867 : cur_expr->avail_occr = cur_occr;
238 : : }
239 : :
240 : : /* Record bitmap_index of the implicit set in implicit_set_indexes. */
241 : 15363867 : if (implicit)
242 : 5870753 : implicit_set_indexes[BLOCK_FOR_INSN (insn)->index]
243 : 5870753 : = cur_expr->bitmap_index;
244 : 15363867 : }
245 : :
246 : : /* Determine whether the rtx X should be treated as a constant for CPROP.
247 : : Since X might be inserted more than once we have to take care that it
248 : : is sharable. */
249 : :
250 : : static bool
251 : 198439691 : cprop_constant_p (const_rtx x)
252 : : {
253 : 198439691 : return CONSTANT_P (x) && (GET_CODE (x) != CONST || shared_const_p (x));
254 : : }
255 : :
256 : : /* Determine whether the rtx X should be treated as a register that can
257 : : be propagated. Any pseudo-register is fine. */
258 : :
259 : : static bool
260 : 503774263 : cprop_reg_p (const_rtx x)
261 : : {
262 : 369860973 : return REG_P (x) && !HARD_REGISTER_P (x);
263 : : }
264 : :
265 : : /* Scan SET present in INSN and add an entry to the hash TABLE.
266 : : IMPLICIT is true if it's an implicit set, false otherwise. */
267 : :
268 : : static void
269 : 138518339 : hash_scan_set (rtx set, rtx_insn *insn, struct hash_table_d *table,
270 : : bool implicit)
271 : : {
272 : 138518339 : rtx src = SET_SRC (set);
273 : 138518339 : rtx dest = SET_DEST (set);
274 : :
275 : 201250764 : if (cprop_reg_p (dest)
276 : 62732425 : && reg_available_p (dest, insn)
277 : 62124031 : && can_copy_p (GET_MODE (dest)))
278 : : {
279 : : /* See if a REG_EQUAL note shows this equivalent to a simpler expression.
280 : :
281 : : This allows us to do a single CPROP pass and still eliminate
282 : : redundant constants, addresses or other expressions that are
283 : : constructed with multiple instructions.
284 : :
285 : : However, keep the original SRC if INSN is a simple reg-reg move. In
286 : : In this case, there will almost always be a REG_EQUAL note on the
287 : : insn that sets SRC. By recording the REG_EQUAL value here as SRC
288 : : for INSN, we miss copy propagation opportunities.
289 : :
290 : : Note that this does not impede profitable constant propagations. We
291 : : "look through" reg-reg sets in lookup_set. */
292 : 62124031 : rtx note = find_reg_equal_equiv_note (insn);
293 : 62124031 : if (note != 0
294 : 4146903 : && REG_NOTE_KIND (note) == REG_EQUAL
295 : 3720064 : && !REG_P (src)
296 : 65550928 : && cprop_constant_p (XEXP (note, 0)))
297 : 1686039 : src = XEXP (note, 0), set = gen_rtx_SET (dest, src);
298 : :
299 : : /* Record sets for constant/copy propagation. */
300 : 62124031 : if ((cprop_reg_p (src)
301 : 2399686 : && src != dest
302 : 2399686 : && reg_available_p (src, insn))
303 : 59850732 : || cprop_constant_p (src))
304 : 15363867 : insert_set_in_table (dest, src, insn, table, implicit);
305 : : }
306 : 138518339 : }
307 : :
308 : : /* Process INSN and add hash table entries as appropriate. */
309 : :
310 : : static void
311 : 139197515 : hash_scan_insn (rtx_insn *insn, struct hash_table_d *table)
312 : : {
313 : 139197515 : rtx pat = PATTERN (insn);
314 : 139197515 : int i;
315 : :
316 : : /* Pick out the sets of INSN and for other forms of instructions record
317 : : what's been modified. */
318 : :
319 : 139197515 : if (GET_CODE (pat) == SET)
320 : 109966255 : hash_scan_set (pat, insn, table, false);
321 : 29231260 : else if (GET_CODE (pat) == PARALLEL)
322 : 66662026 : for (i = 0; i < XVECLEN (pat, 0); i++)
323 : : {
324 : 44782274 : rtx x = XVECEXP (pat, 0, i);
325 : :
326 : 44782274 : if (GET_CODE (x) == SET)
327 : 22601839 : hash_scan_set (x, insn, table, false);
328 : : }
329 : 139197515 : }
330 : :
331 : : /* Dump the hash table TABLE to file FILE under the name NAME. */
332 : :
333 : : static void
334 : 63 : dump_hash_table (FILE *file, const char *name, struct hash_table_d *table)
335 : : {
336 : 63 : int i;
337 : : /* Flattened out table, so it's printed in proper order. */
338 : 63 : struct cprop_expr **flat_table;
339 : 63 : unsigned int *hash_val;
340 : 63 : struct cprop_expr *expr;
341 : :
342 : 63 : flat_table = XCNEWVEC (struct cprop_expr *, table->n_elems);
343 : 63 : hash_val = XNEWVEC (unsigned int, table->n_elems);
344 : :
345 : 1367 : for (i = 0; i < (int) table->size; i++)
346 : 1380 : for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash)
347 : : {
348 : 139 : flat_table[expr->bitmap_index] = expr;
349 : 139 : hash_val[expr->bitmap_index] = i;
350 : : }
351 : :
352 : 63 : fprintf (file, "%s hash table (%d buckets, %d entries)\n",
353 : : name, table->size, table->n_elems);
354 : :
355 : 265 : for (i = 0; i < (int) table->n_elems; i++)
356 : 139 : if (flat_table[i] != 0)
357 : : {
358 : 139 : expr = flat_table[i];
359 : 139 : fprintf (file, "Index %d (hash value %d)\n ",
360 : 139 : expr->bitmap_index, hash_val[i]);
361 : 139 : print_rtl (file, expr->dest);
362 : 139 : fprintf (file, " := ");
363 : 139 : print_rtl (file, expr->src);
364 : 139 : fprintf (file, "\n");
365 : : }
366 : :
367 : 63 : fprintf (file, "\n");
368 : :
369 : 63 : free (flat_table);
370 : 63 : free (hash_val);
371 : 63 : }
372 : :
373 : : /* Record as unavailable all registers that are DEF operands of INSN. */
374 : :
375 : : static void
376 : 139197515 : make_set_regs_unavailable (rtx_insn *insn)
377 : : {
378 : 139197515 : df_ref def;
379 : :
380 : 1156703105 : FOR_EACH_INSN_DEF (def, insn)
381 : 1017505590 : SET_REGNO_REG_SET (reg_set_bitmap, DF_REF_REGNO (def));
382 : 139197515 : }
383 : :
384 : : /* Top level function to create an assignment hash table.
385 : :
386 : : Assignment entries are placed in the hash table if
387 : : - they are of the form (set (pseudo-reg) src),
388 : : - src is something we want to perform const/copy propagation on,
389 : : - none of the operands or target are subsequently modified in the block
390 : :
391 : : Currently src must be a pseudo-reg or a const_int.
392 : :
393 : : TABLE is the table computed. */
394 : :
395 : : static void
396 : 1457592 : compute_hash_table_work (struct hash_table_d *table)
397 : : {
398 : 1457592 : basic_block bb;
399 : :
400 : : /* Allocate vars to track sets of regs. */
401 : 1457592 : reg_set_bitmap = ALLOC_REG_SET (NULL);
402 : :
403 : 30793554 : FOR_EACH_BB_FN (bb, cfun)
404 : : {
405 : 29335962 : rtx_insn *insn;
406 : :
407 : : /* Reset tables used to keep track of what's not yet invalid [since
408 : : the end of the block]. */
409 : 29335962 : CLEAR_REG_SET (reg_set_bitmap);
410 : :
411 : : /* Go over all insns from the last to the first. This is convenient
412 : : for tracking available registers, i.e. not set between INSN and
413 : : the end of the basic block BB. */
414 : 330249788 : FOR_BB_INSNS_REVERSE (bb, insn)
415 : : {
416 : : /* Only real insns are interesting. */
417 : 300913826 : if (!NONDEBUG_INSN_P (insn))
418 : 161716311 : continue;
419 : :
420 : : /* Record interesting sets from INSN in the hash table. */
421 : 139197515 : hash_scan_insn (insn, table);
422 : :
423 : : /* Any registers set in INSN will make SETs above it not AVAIL. */
424 : 139197515 : make_set_regs_unavailable (insn);
425 : : }
426 : :
427 : : /* Insert implicit sets in the hash table, pretending they appear as
428 : : insns at the head of the basic block. */
429 : 29335962 : if (implicit_sets[bb->index] != NULL_RTX)
430 : 5950245 : hash_scan_set (implicit_sets[bb->index], BB_HEAD (bb), table, true);
431 : : }
432 : :
433 : 1457592 : FREE_REG_SET (reg_set_bitmap);
434 : 1457592 : }
435 : :
436 : : /* Allocate space for the set/expr hash TABLE.
437 : : It is used to determine the number of buckets to use. */
438 : :
439 : : static void
440 : 1457592 : alloc_hash_table (struct hash_table_d *table)
441 : : {
442 : 1457592 : int n;
443 : :
444 : 1457592 : n = get_max_insn_count ();
445 : :
446 : 1457592 : table->size = n / 4;
447 : 1457592 : if (table->size < 11)
448 : 534379 : table->size = 11;
449 : :
450 : : /* Attempt to maintain efficient use of hash table.
451 : : Making it an odd number is simplest for now.
452 : : ??? Later take some measurements. */
453 : 1457592 : table->size |= 1;
454 : 1457592 : n = table->size * sizeof (struct cprop_expr *);
455 : 1457592 : table->table = XNEWVAR (struct cprop_expr *, n);
456 : 1457592 : }
457 : :
458 : : /* Free things allocated by alloc_hash_table. */
459 : :
460 : : static void
461 : 1457592 : free_hash_table (struct hash_table_d *table)
462 : : {
463 : 1457592 : free (table->table);
464 : 0 : }
465 : :
466 : : /* Compute the hash TABLE for doing copy/const propagation or
467 : : expression hash table. */
468 : :
469 : : static void
470 : 1457592 : compute_hash_table (struct hash_table_d *table)
471 : : {
472 : : /* Initialize count of number of entries in hash table. */
473 : 1457592 : table->n_elems = 0;
474 : 1457592 : memset (table->table, 0, table->size * sizeof (struct cprop_expr *));
475 : :
476 : 1457592 : compute_hash_table_work (table);
477 : 1457592 : }
478 : :
479 : : /* Expression tracking support. */
480 : :
481 : : /* Lookup REGNO in the set TABLE. The result is a pointer to the
482 : : table entry, or NULL if not found. */
483 : :
484 : : static struct cprop_expr *
485 : 85815029 : lookup_set (unsigned int regno, struct hash_table_d *table)
486 : : {
487 : 85815029 : unsigned int hash = hash_mod (regno, table->size);
488 : 85815029 : struct cprop_expr *expr;
489 : :
490 : 85815029 : expr = table->table[hash];
491 : :
492 : 92832026 : while (expr && REGNO (expr->dest) != regno)
493 : 7016997 : expr = expr->next_same_hash;
494 : :
495 : 85815029 : return expr;
496 : : }
497 : :
498 : : /* Return the next entry for REGNO in list EXPR. */
499 : :
500 : : static struct cprop_expr *
501 : 0 : next_set (unsigned int regno, struct cprop_expr *expr)
502 : : {
503 : 36566127 : do
504 : 36566127 : expr = expr->next_same_hash;
505 : 72340400 : while (expr && REGNO (expr->dest) != regno);
506 : :
507 : 0 : return expr;
508 : : }
509 : :
510 : : /* Reset tables used to keep track of what's still available [since the
511 : : start of the block]. */
512 : :
513 : : static void
514 : 27363844 : reset_opr_set_tables (void)
515 : : {
516 : : /* Maintain a bitmap of which regs have been set since beginning of
517 : : the block. */
518 : 0 : CLEAR_REG_SET (reg_set_bitmap);
519 : 0 : }
520 : :
521 : : /* Return true if the register X has not been set yet [since the
522 : : start of the basic block containing INSN]. */
523 : :
524 : : static bool
525 : 154429149 : reg_not_set_p (const_rtx x, const rtx_insn *insn ATTRIBUTE_UNUSED)
526 : : {
527 : 0 : return ! REGNO_REG_SET_P (reg_set_bitmap, REGNO (x));
528 : : }
529 : :
530 : : /* Record things set by INSN.
531 : : This data is used by reg_not_set_p. */
532 : :
533 : : static void
534 : 229440433 : mark_oprs_set (rtx_insn *insn)
535 : : {
536 : 229440433 : df_ref def;
537 : :
538 : 1137093670 : FOR_EACH_INSN_DEF (def, insn)
539 : 907653237 : SET_REGNO_REG_SET (reg_set_bitmap, DF_REF_REGNO (def));
540 : 229440433 : }
541 : :
542 : : /* Compute copy/constant propagation working variables. */
543 : :
544 : : /* Local properties of assignments. */
545 : : static sbitmap *cprop_avloc;
546 : : static sbitmap *cprop_kill;
547 : :
548 : : /* Global properties of assignments (computed from the local properties). */
549 : : static sbitmap *cprop_avin;
550 : : static sbitmap *cprop_avout;
551 : :
552 : : /* Allocate vars used for copy/const propagation. N_BLOCKS is the number of
553 : : basic blocks. N_SETS is the number of sets. */
554 : :
555 : : static void
556 : 1311293 : alloc_cprop_mem (int n_blocks, int n_sets)
557 : : {
558 : 1311293 : cprop_avloc = sbitmap_vector_alloc (n_blocks, n_sets);
559 : 1311293 : cprop_kill = sbitmap_vector_alloc (n_blocks, n_sets);
560 : :
561 : 1311293 : cprop_avin = sbitmap_vector_alloc (n_blocks, n_sets);
562 : 1311293 : cprop_avout = sbitmap_vector_alloc (n_blocks, n_sets);
563 : 1311293 : }
564 : :
565 : : /* Free vars used by copy/const propagation. */
566 : :
567 : : static void
568 : 1311293 : free_cprop_mem (void)
569 : : {
570 : 1311293 : sbitmap_vector_free (cprop_avloc);
571 : 1311293 : sbitmap_vector_free (cprop_kill);
572 : 1311293 : sbitmap_vector_free (cprop_avin);
573 : 1311293 : sbitmap_vector_free (cprop_avout);
574 : 1311293 : }
575 : :
576 : : /* Compute the local properties of each recorded expression.
577 : :
578 : : Local properties are those that are defined by the block, irrespective of
579 : : other blocks.
580 : :
581 : : An expression is killed in a block if its operands, either DEST or SRC, are
582 : : modified in the block.
583 : :
584 : : An expression is computed (locally available) in a block if it is computed
585 : : at least once and expression would contain the same value if the
586 : : computation was moved to the end of the block.
587 : :
588 : : KILL and COMP are destination sbitmaps for recording local properties. */
589 : :
590 : : static void
591 : 1311293 : compute_local_properties (sbitmap *kill, sbitmap *comp,
592 : : struct hash_table_d *table)
593 : : {
594 : 1311293 : unsigned int i;
595 : :
596 : : /* Initialize the bitmaps that were passed in. */
597 : 1311293 : bitmap_vector_clear (kill, last_basic_block_for_fn (cfun));
598 : 1311293 : bitmap_vector_clear (comp, last_basic_block_for_fn (cfun));
599 : :
600 : 63723868 : for (i = 0; i < table->size; i++)
601 : : {
602 : 62412575 : struct cprop_expr *expr;
603 : :
604 : 75872878 : for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash)
605 : : {
606 : 13460303 : int indx = expr->bitmap_index;
607 : 13460303 : df_ref def;
608 : 13460303 : struct cprop_occr *occr;
609 : :
610 : : /* For each definition of the destination pseudo-reg, the expression
611 : : is killed in the block where the definition is. */
612 : 13460303 : for (def = DF_REG_DEF_CHAIN (REGNO (expr->dest));
613 : 82665048 : def; def = DF_REF_NEXT_REG (def))
614 : 69204745 : bitmap_set_bit (kill[DF_REF_BB (def)->index], indx);
615 : :
616 : : /* If the source is a pseudo-reg, for each definition of the source,
617 : : the expression is killed in the block where the definition is. */
618 : 13460303 : if (REG_P (expr->src))
619 : 2068009 : for (def = DF_REG_DEF_CHAIN (REGNO (expr->src));
620 : 5841155 : def; def = DF_REF_NEXT_REG (def))
621 : 3773146 : bitmap_set_bit (kill[DF_REF_BB (def)->index], indx);
622 : :
623 : : /* The occurrences recorded in avail_occr are exactly those that
624 : : are locally available in the block where they are. */
625 : 28824170 : for (occr = expr->avail_occr; occr != NULL; occr = occr->next)
626 : : {
627 : 15363867 : bitmap_set_bit (comp[BLOCK_FOR_INSN (occr->insn)->index], indx);
628 : : }
629 : : }
630 : : }
631 : 1311293 : }
632 : :
633 : : /* Hash table support. */
634 : :
635 : : /* Top level routine to do the dataflow analysis needed by copy/const
636 : : propagation. */
637 : :
638 : : static void
639 : 1311293 : compute_cprop_data (void)
640 : : {
641 : 1311293 : basic_block bb;
642 : :
643 : 1311293 : compute_local_properties (cprop_kill, cprop_avloc, &set_hash_table);
644 : 1311293 : compute_available (cprop_avloc, cprop_kill, cprop_avout, cprop_avin);
645 : :
646 : : /* Merge implicit sets into CPROP_AVIN. They are always available at the
647 : : entry of their basic block. We need to do this because 1) implicit sets
648 : : aren't recorded for the local pass so they cannot be propagated within
649 : : their basic block by this pass and 2) the global pass would otherwise
650 : : propagate them only in the successors of their basic block. */
651 : 29986430 : FOR_EACH_BB_FN (bb, cfun)
652 : : {
653 : 28675137 : int index = implicit_set_indexes[bb->index];
654 : 28675137 : if (index != -1)
655 : 5870753 : bitmap_set_bit (cprop_avin[bb->index], index);
656 : : }
657 : 1311293 : }
658 : :
659 : : /* Copy/constant propagation. */
660 : :
661 : : /* Maximum number of register uses in an insn that we handle. */
662 : : #define MAX_USES 8
663 : :
664 : : /* Table of uses (registers, both hard and pseudo) found in an insn.
665 : : Allocated statically to avoid alloc/free complexity and overhead. */
666 : : static rtx reg_use_table[MAX_USES];
667 : :
668 : : /* Index into `reg_use_table' while building it. */
669 : : static unsigned reg_use_count;
670 : :
671 : : /* Set up a list of register numbers used in INSN. The found uses are stored
672 : : in `reg_use_table'. `reg_use_count' is initialized to zero before entry,
673 : : and contains the number of uses in the table upon exit.
674 : :
675 : : ??? If a register appears multiple times we will record it multiple times.
676 : : This doesn't hurt anything but it will slow things down. */
677 : :
678 : : static void
679 : 994313291 : find_used_regs (rtx *xptr, void *data ATTRIBUTE_UNUSED)
680 : : {
681 : 994313291 : int i, j;
682 : 994313291 : enum rtx_code code;
683 : 994313291 : const char *fmt;
684 : 994313291 : rtx x = *xptr;
685 : :
686 : : /* repeat is used to turn tail-recursion into iteration since GCC
687 : : can't do it when there's no return value. */
688 : 1398363639 : repeat:
689 : 1398363639 : if (x == 0)
690 : : return;
691 : :
692 : 1398363639 : code = GET_CODE (x);
693 : 1398363639 : if (REG_P (x))
694 : : {
695 : 325280615 : if (reg_use_count == MAX_USES)
696 : : return;
697 : :
698 : 325254650 : reg_use_table[reg_use_count] = x;
699 : 325254650 : reg_use_count++;
700 : : }
701 : :
702 : : /* Recursively scan the operands of this expression. */
703 : :
704 : 2885557067 : for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
705 : : {
706 : 1891269741 : if (fmt[i] == 'e')
707 : : {
708 : : /* If we are about to do the last recursive call
709 : : needed at this level, change it into iteration.
710 : : This function is called enough to be worth it. */
711 : 838384899 : if (i == 0)
712 : : {
713 : 404050348 : x = XEXP (x, 0);
714 : 404050348 : goto repeat;
715 : : }
716 : :
717 : 434334551 : find_used_regs (&XEXP (x, i), data);
718 : : }
719 : 1052884842 : else if (fmt[i] == 'E')
720 : 28456219 : for (j = 0; j < XVECLEN (x, i); j++)
721 : 20280965 : find_used_regs (&XVECEXP (x, i, j), data);
722 : : }
723 : : }
724 : :
725 : : /* Try to replace all uses of FROM in INSN with TO.
726 : : Return true if successful. */
727 : :
728 : : static bool
729 : 7240299 : try_replace_reg (rtx from, rtx to, rtx_insn *insn)
730 : : {
731 : 7240299 : rtx note = find_reg_equal_equiv_note (insn);
732 : 7240299 : rtx src = 0;
733 : 7240299 : bool success = false;
734 : 7240299 : rtx set = single_set (insn);
735 : :
736 : 7240299 : bool check_rtx_costs = true;
737 : 7240299 : bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn));
738 : 7240299 : int old_cost = set ? set_rtx_cost (set, speed) : 0;
739 : :
740 : 6835588 : if (!set
741 : 6835588 : || CONSTANT_P (SET_SRC (set))
742 : 6674322 : || (note != 0
743 : 2566962 : && REG_NOTE_KIND (note) == REG_EQUAL
744 : 2566962 : && (GET_CODE (XEXP (note, 0)) == CONST
745 : 2557338 : || CONSTANT_P (XEXP (note, 0)))))
746 : : check_rtx_costs = false;
747 : :
748 : : /* Usually we substitute easy stuff, so we won't copy everything.
749 : : We however need to take care to not duplicate non-trivial CONST
750 : : expressions. */
751 : 7240299 : to = copy_rtx (to);
752 : :
753 : 7240299 : validate_replace_src_group (from, to, insn);
754 : :
755 : : /* If TO is a constant, check the cost of the set after propagation
756 : : to the cost of the set before the propagation. If the cost is
757 : : higher, then do not replace FROM with TO. */
758 : :
759 : 7240299 : if (check_rtx_costs
760 : 5879680 : && CONSTANT_P (to)
761 : 11162648 : && set_rtx_cost (set, speed) > old_cost)
762 : : {
763 : 2557159 : cancel_changes (0);
764 : 2557159 : return false;
765 : : }
766 : :
767 : :
768 : 4683140 : if (num_changes_pending () && apply_change_group ())
769 : : success = true;
770 : :
771 : : /* Try to simplify SET_SRC if we have substituted a constant. */
772 : 4683140 : if (success && set && CONSTANT_P (to))
773 : : {
774 : 340251 : src = simplify_rtx (SET_SRC (set));
775 : :
776 : 340251 : if (src)
777 : 5976 : validate_change (insn, &SET_SRC (set), src, 0);
778 : : }
779 : :
780 : : /* If there is already a REG_EQUAL note, update the expression in it
781 : : with our replacement. */
782 : 4683140 : if (note != 0 && REG_NOTE_KIND (note) == REG_EQUAL)
783 : 2144118 : set_unique_reg_note (insn, REG_EQUAL,
784 : : simplify_replace_rtx (XEXP (note, 0), from, to));
785 : 4683140 : if (!success && set && reg_mentioned_p (from, SET_SRC (set)))
786 : : {
787 : : /* If above failed and this is a single set, try to simplify the source
788 : : of the set given our substitution. We could perhaps try this for
789 : : multiple SETs, but it probably won't buy us anything. */
790 : 1634621 : src = simplify_replace_rtx (SET_SRC (set), from, to);
791 : :
792 : 1634621 : if (!rtx_equal_p (src, SET_SRC (set))
793 : 1634621 : && validate_change (insn, &SET_SRC (set), src, 0))
794 : : success = true;
795 : :
796 : : /* If we've failed perform the replacement, have a single SET to
797 : : a REG destination and don't yet have a note, add a REG_EQUAL note
798 : : to not lose information. */
799 : 166531 : if (!success && note == 0 && set != 0 && REG_P (SET_DEST (set))
800 : 1782143 : && !contains_paradoxical_subreg_p (SET_SRC (set)))
801 : 146733 : note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src));
802 : : }
803 : :
804 : 4683140 : if (set && MEM_P (SET_DEST (set)) && reg_mentioned_p (from, SET_DEST (set)))
805 : : {
806 : : /* Registers can also appear as uses in SET_DEST if it is a MEM.
807 : : We could perhaps try this for multiple SETs, but it probably
808 : : won't buy us anything. */
809 : 13970 : rtx dest = simplify_replace_rtx (SET_DEST (set), from, to);
810 : :
811 : 13970 : if (!rtx_equal_p (dest, SET_DEST (set))
812 : 13970 : && validate_change (insn, &SET_DEST (set), dest, 0))
813 : : success = true;
814 : : }
815 : :
816 : : /* REG_EQUAL may get simplified into register.
817 : : We don't allow that. Remove that note. This code ought
818 : : not to happen, because previous code ought to synthesize
819 : : reg-reg move, but be on the safe side. */
820 : 4683140 : if (note && REG_NOTE_KIND (note) == REG_EQUAL && REG_P (XEXP (note, 0)))
821 : 0 : remove_note (insn, note);
822 : :
823 : : return success;
824 : : }
825 : :
826 : : /* Find a set of REGNOs that are available on entry to INSN's block. If found,
827 : : SET_RET[0] will be assigned a set with a register source and SET_RET[1] a
828 : : set with a constant source. If not found the corresponding entry is set to
829 : : NULL. */
830 : :
831 : : static void
832 : 83344728 : find_avail_set (int regno, rtx_insn *insn, struct cprop_expr *set_ret[2])
833 : : {
834 : 83344728 : set_ret[0] = set_ret[1] = NULL;
835 : :
836 : : /* Loops are not possible here. To get a loop we would need two sets
837 : : available at the start of the block containing INSN. i.e. we would
838 : : need two sets like this available at the start of the block:
839 : :
840 : : (set (reg X) (reg Y))
841 : : (set (reg Y) (reg X))
842 : :
843 : : This cannot happen since the set of (reg Y) would have killed the
844 : : set of (reg X) making it unavailable at the start of this block. */
845 : 84568678 : while (1)
846 : : {
847 : 83956703 : rtx src;
848 : 83956703 : struct cprop_expr *set = lookup_set (regno, &set_hash_table);
849 : :
850 : : /* Find a set that is available at the start of the block
851 : : which contains INSN. */
852 : 83956703 : while (set)
853 : : {
854 : 35826439 : if (bitmap_bit_p (cprop_avin[BLOCK_FOR_INSN (insn)->index],
855 : : set->bitmap_index))
856 : : break;
857 : 117794203 : set = next_set (regno, set);
858 : : }
859 : :
860 : : /* If no available set was found we've reached the end of the
861 : : (possibly empty) copy chain. */
862 : 1988939 : if (set == 0)
863 : : break;
864 : :
865 : 1988939 : src = set->src;
866 : :
867 : : /* We know the set is available.
868 : : Now check that SRC is locally anticipatable (i.e. none of the
869 : : source operands have changed since the start of the block).
870 : :
871 : : If the source operand changed, we may still use it for the next
872 : : iteration of this loop, but we may not use it for substitutions. */
873 : :
874 : 1988939 : if (cprop_constant_p (src))
875 : 1376964 : set_ret[1] = set;
876 : 611975 : else if (reg_not_set_p (src, insn))
877 : 609275 : set_ret[0] = set;
878 : :
879 : : /* If the source of the set is anything except a register, then
880 : : we have reached the end of the copy chain. */
881 : 1988939 : if (! REG_P (src))
882 : : break;
883 : :
884 : : /* Follow the copy chain, i.e. start another iteration of the loop
885 : : and see if we have an available copy into SRC. */
886 : 611975 : regno = REGNO (src);
887 : 611975 : }
888 : 83344728 : }
889 : :
890 : : /* Subroutine of cprop_insn that tries to propagate constants into
891 : : JUMP_INSNS. JUMP must be a conditional jump. If SETCC is non-NULL
892 : : it is the instruction that immediately precedes JUMP, and must be a
893 : : single SET of a register. FROM is what we will try to replace,
894 : : SRC is the constant we will try to substitute for it. Return true
895 : : if a change was made. */
896 : :
897 : : static bool
898 : 575817 : cprop_jump (basic_block bb, rtx_insn *setcc, rtx_insn *jump, rtx from, rtx src)
899 : : {
900 : 575817 : rtx new_rtx, set_src, note_src;
901 : 575817 : rtx set = pc_set (jump);
902 : 575817 : rtx note = find_reg_equal_equiv_note (jump);
903 : :
904 : 575817 : if (note)
905 : : {
906 : 0 : note_src = XEXP (note, 0);
907 : 0 : if (GET_CODE (note_src) == EXPR_LIST)
908 : : note_src = NULL_RTX;
909 : : }
910 : : else note_src = NULL_RTX;
911 : :
912 : : /* Prefer REG_EQUAL notes except those containing EXPR_LISTs. */
913 : 575817 : set_src = note_src ? note_src : SET_SRC (set);
914 : :
915 : : /* First substitute the SETCC condition into the JUMP instruction,
916 : : then substitute that given values into this expanded JUMP. */
917 : 575817 : if (setcc != NULL_RTX
918 : 575817 : && !modified_between_p (from, setcc, jump)
919 : 1151634 : && !modified_between_p (src, setcc, jump))
920 : : {
921 : 575817 : rtx setcc_src;
922 : 575817 : rtx setcc_set = single_set (setcc);
923 : 575817 : rtx setcc_note = find_reg_equal_equiv_note (setcc);
924 : 239287 : setcc_src = (setcc_note && GET_CODE (XEXP (setcc_note, 0)) != EXPR_LIST)
925 : 575817 : ? XEXP (setcc_note, 0) : SET_SRC (setcc_set);
926 : 575817 : set_src = simplify_replace_rtx (set_src, SET_DEST (setcc_set),
927 : : setcc_src);
928 : : }
929 : : else
930 : : setcc = NULL;
931 : :
932 : 575817 : new_rtx = simplify_replace_rtx (set_src, from, src);
933 : :
934 : : /* If no simplification can be made, then try the next register. */
935 : 575817 : if (rtx_equal_p (new_rtx, SET_SRC (set)))
936 : : return false;
937 : :
938 : : /* If this is now a no-op delete it, otherwise this must be a valid insn. */
939 : 572205 : if (new_rtx == pc_rtx)
940 : 1942 : delete_insn (jump);
941 : : else
942 : : {
943 : : /* Ensure the value computed inside the jump insn to be equivalent
944 : : to one computed by setcc. */
945 : 570263 : if (setcc && modified_in_p (new_rtx, setcc))
946 : : return false;
947 : 3649 : if (! validate_unshare_change (jump, &SET_SRC (set), new_rtx, 0))
948 : : {
949 : : /* When (some) constants are not valid in a comparison, and there
950 : : are two registers to be replaced by constants before the entire
951 : : comparison can be folded into a constant, we need to keep
952 : : intermediate information in REG_EQUAL notes. For targets with
953 : : separate compare insns, such notes are added by try_replace_reg.
954 : : When we have a combined compare-and-branch instruction, however,
955 : : we need to attach a note to the branch itself to make this
956 : : optimization work. */
957 : :
958 : 0 : if (!rtx_equal_p (new_rtx, note_src))
959 : 0 : set_unique_reg_note (jump, REG_EQUAL, copy_rtx (new_rtx));
960 : 0 : return false;
961 : : }
962 : :
963 : : /* Remove REG_EQUAL note after simplification. */
964 : 3649 : if (note_src)
965 : 0 : remove_note (jump, note);
966 : : }
967 : :
968 : 5591 : global_const_prop_count++;
969 : 5591 : if (dump_file != NULL)
970 : : {
971 : 0 : fprintf (dump_file,
972 : : "GLOBAL CONST-PROP: Replacing reg %d in jump_insn %d with "
973 : 0 : "constant ", REGNO (from), INSN_UID (jump));
974 : 0 : print_rtl (dump_file, src);
975 : 0 : fprintf (dump_file, "\n");
976 : : }
977 : 5591 : purge_dead_edges (bb);
978 : :
979 : : /* If a conditional jump has been changed into unconditional jump, remove
980 : : the jump and make the edge fallthru - this is always called in
981 : : cfglayout mode. */
982 : 5591 : if (new_rtx != pc_rtx && simplejump_p (jump))
983 : : {
984 : 3649 : edge e;
985 : 3649 : edge_iterator ei;
986 : :
987 : 3649 : FOR_EACH_EDGE (e, ei, bb->succs)
988 : 3649 : if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
989 : 3649 : && BB_HEAD (e->dest) == JUMP_LABEL (jump))
990 : : {
991 : 3649 : e->flags |= EDGE_FALLTHRU;
992 : 3649 : break;
993 : : }
994 : 3649 : delete_insn (jump);
995 : : }
996 : :
997 : : return true;
998 : : }
999 : :
1000 : : /* Subroutine of cprop_insn that tries to propagate constants. FROM is what
1001 : : we will try to replace, SRC is the constant we will try to substitute for
1002 : : it and INSN is the instruction where this will be happening. */
1003 : :
1004 : : static bool
1005 : 5142064 : constprop_register (rtx from, rtx src, rtx_insn *insn)
1006 : : {
1007 : 5142064 : rtx sset;
1008 : 5142064 : rtx_insn *next_insn;
1009 : :
1010 : : /* Check for reg setting instructions followed by conditional branch
1011 : : instructions first. */
1012 : 5142064 : if ((sset = single_set (insn)) != NULL
1013 : 4819641 : && (next_insn = next_nondebug_insn (insn)) != NULL
1014 : 4817241 : && any_condjump_p (next_insn)
1015 : 5717887 : && onlyjump_p (next_insn))
1016 : : {
1017 : 575823 : rtx dest = SET_DEST (sset);
1018 : 575823 : if (REG_P (dest)
1019 : 575823 : && cprop_jump (BLOCK_FOR_INSN (insn), insn, next_insn,
1020 : : from, src))
1021 : : return true;
1022 : : }
1023 : :
1024 : : /* Handle normal insns next. */
1025 : 5136473 : if (NONJUMP_INSN_P (insn) && try_replace_reg (from, src, insn))
1026 : : return true;
1027 : :
1028 : : /* Try to propagate a CONST_INT into a conditional jump.
1029 : : We're pretty specific about what we will handle in this
1030 : : code, we can extend this as necessary over time.
1031 : :
1032 : : Right now the insn in question must look like
1033 : : (set (pc) (if_then_else ...)) */
1034 : 4788009 : else if (any_condjump_p (insn) && onlyjump_p (insn))
1035 : 0 : return cprop_jump (BLOCK_FOR_INSN (insn), NULL, insn, from, src);
1036 : : return false;
1037 : : }
1038 : :
1039 : : /* Perform constant and copy propagation on INSN.
1040 : : Return true if a change was made. */
1041 : :
1042 : : static bool
1043 : 229440433 : cprop_insn (rtx_insn *insn)
1044 : : {
1045 : 229440433 : unsigned i;
1046 : 229440433 : int changed_this_round;
1047 : 229440433 : bool changed = false;
1048 : 230152932 : rtx note;
1049 : :
1050 : 230152932 : do
1051 : : {
1052 : 230152932 : changed_this_round = 0;
1053 : 230152932 : reg_use_count = 0;
1054 : 230152932 : note_uses (&PATTERN (insn), find_used_regs, NULL);
1055 : :
1056 : : /* We may win even when propagating constants into notes. */
1057 : 230152932 : note = find_reg_equal_equiv_note (insn);
1058 : 230152932 : if (note)
1059 : 6676377 : find_used_regs (&XEXP (note, 0), NULL);
1060 : :
1061 : 383970106 : for (i = 0; i < reg_use_count; i++)
1062 : : {
1063 : 153817174 : rtx reg_used = reg_use_table[i];
1064 : 153817174 : unsigned int regno = REGNO (reg_used);
1065 : 153817174 : rtx src_cst = NULL, src_reg = NULL;
1066 : 153817174 : struct cprop_expr *set[2];
1067 : :
1068 : : /* If the register has already been set in this block, there's
1069 : : nothing we can do. */
1070 : 153817174 : if (! reg_not_set_p (reg_used, insn))
1071 : 70472446 : continue;
1072 : :
1073 : : /* Find an assignment that sets reg_used and is available
1074 : : at the start of the block. */
1075 : 83344728 : find_avail_set (regno, insn, set);
1076 : 83344728 : if (set[0])
1077 : 608790 : src_reg = set[0]->src;
1078 : 83344728 : if (set[1])
1079 : 1376964 : src_cst = set[1]->src;
1080 : :
1081 : : /* Constant propagation. */
1082 : 1376964 : if (src_cst && cprop_constant_p (src_cst)
1083 : 2753928 : && constprop_register (reg_used, src_cst, insn))
1084 : : {
1085 : 128343 : changed = true;
1086 : 128343 : changed_this_round = 1;
1087 : 128343 : global_const_prop_count++;
1088 : 128343 : if (dump_file != NULL)
1089 : : {
1090 : 6 : fprintf (dump_file,
1091 : : "GLOBAL CONST-PROP: Replacing reg %d in ", regno);
1092 : 6 : fprintf (dump_file, "insn %d with constant ",
1093 : 6 : INSN_UID (insn));
1094 : 6 : print_rtl (dump_file, src_cst);
1095 : 6 : fprintf (dump_file, "\n");
1096 : : }
1097 : 128343 : if (insn->deleted ())
1098 : 0 : return true;
1099 : : }
1100 : : /* Copy propagation. */
1101 : 83344728 : else if (src_reg && cprop_reg_p (src_reg)
1102 : 608084 : && REGNO (src_reg) != regno
1103 : 83824469 : && try_replace_reg (reg_used, src_reg, insn))
1104 : : {
1105 : 588763 : changed = true;
1106 : 588763 : changed_this_round = 1;
1107 : 588763 : global_copy_prop_count++;
1108 : 588763 : if (dump_file != NULL)
1109 : : {
1110 : 10 : fprintf (dump_file,
1111 : : "GLOBAL COPY-PROP: Replacing reg %d in insn %d",
1112 : 10 : regno, INSN_UID (insn));
1113 : 10 : fprintf (dump_file, " with reg %d\n", REGNO (src_reg));
1114 : : }
1115 : :
1116 : : /* The original insn setting reg_used may or may not now be
1117 : : deletable. We leave the deletion to DCE. */
1118 : : /* FIXME: If it turns out that the insn isn't deletable,
1119 : : then we may have unnecessarily extended register lifetimes
1120 : : and made things worse. */
1121 : : }
1122 : : }
1123 : : }
1124 : : /* If try_replace_reg simplified the insn, the regs found by find_used_regs
1125 : : may not be valid anymore. Start over. */
1126 : 230152932 : while (changed_this_round);
1127 : :
1128 : 229440433 : if (changed && DEBUG_INSN_P (insn))
1129 : : return false;
1130 : :
1131 : : return changed;
1132 : : }
1133 : :
1134 : : /* Like find_used_regs, but avoid recording uses that appear in
1135 : : input-output contexts such as zero_extract or pre_dec. This
1136 : : restricts the cases we consider to those for which local cprop
1137 : : can legitimately make replacements. */
1138 : :
1139 : : static void
1140 : 288318376 : local_cprop_find_used_regs (rtx *xptr, void *data)
1141 : : {
1142 : 288318376 : rtx x = *xptr;
1143 : :
1144 : 288318376 : if (x == 0)
1145 : : return;
1146 : :
1147 : 288318376 : switch (GET_CODE (x))
1148 : : {
1149 : : case ZERO_EXTRACT:
1150 : : case SIGN_EXTRACT:
1151 : : case STRICT_LOW_PART:
1152 : : return;
1153 : :
1154 : : case PRE_DEC:
1155 : : case PRE_INC:
1156 : : case POST_DEC:
1157 : : case POST_INC:
1158 : : case PRE_MODIFY:
1159 : : case POST_MODIFY:
1160 : : /* Can only legitimately appear this early in the context of
1161 : : stack pushes for function arguments, but handle all of the
1162 : : codes nonetheless. */
1163 : : return;
1164 : :
1165 : 1027687 : case SUBREG:
1166 : 1027687 : if (read_modify_subreg_p (x))
1167 : : return;
1168 : : break;
1169 : :
1170 : : default:
1171 : : break;
1172 : : }
1173 : :
1174 : 283332820 : find_used_regs (xptr, data);
1175 : : }
1176 : :
1177 : : /* Try to perform local const/copy propagation on X in INSN. */
1178 : :
1179 : : static bool
1180 : 169204113 : do_local_cprop (rtx x, rtx_insn *insn)
1181 : : {
1182 : 169204113 : rtx newreg = NULL, newcnst = NULL;
1183 : :
1184 : : /* Rule out USE instructions and ASM statements as we don't want to
1185 : : change the hard registers mentioned. */
1186 : 169204113 : if (REG_P (x)
1187 : 169204113 : && (cprop_reg_p (x)
1188 : 56960021 : || (GET_CODE (PATTERN (insn)) != USE
1189 : 56250670 : && asm_noperands (PATTERN (insn)) < 0)))
1190 : : {
1191 : 168472456 : cselib_val *val = cselib_lookup (x, GET_MODE (x), 0, VOIDmode);
1192 : 168472456 : struct elt_loc_list *l;
1193 : :
1194 : 168472456 : if (!val)
1195 : : return false;
1196 : 191256186 : for (l = val->locs; l; l = l->next)
1197 : : {
1198 : 123604591 : rtx this_rtx = l->loc;
1199 : 123604591 : rtx note;
1200 : :
1201 : 123604591 : if (cprop_constant_p (this_rtx))
1202 : 3765100 : newcnst = this_rtx;
1203 : 247209182 : if (cprop_reg_p (this_rtx)
1204 : : /* Don't copy propagate if it has attached REG_EQUIV note.
1205 : : At this point this only function parameters should have
1206 : : REG_EQUIV notes and if the argument slot is used somewhere
1207 : : explicitly, it means address of parameter has been taken,
1208 : : so we should not extend the lifetime of the pseudo. */
1209 : 48019263 : && (!(note = find_reg_note (l->setting_insn, REG_EQUIV, NULL_RTX))
1210 : 3120 : || ! MEM_P (XEXP (note, 0))))
1211 : : newreg = this_rtx;
1212 : : }
1213 : 67651595 : if (newcnst && constprop_register (x, newcnst, insn))
1214 : : {
1215 : 225712 : if (dump_file != NULL)
1216 : : {
1217 : 2 : fprintf (dump_file, "LOCAL CONST-PROP: Replacing reg %d in ",
1218 : : REGNO (x));
1219 : 2 : fprintf (dump_file, "insn %d with constant ",
1220 : 2 : INSN_UID (insn));
1221 : 2 : print_rtl (dump_file, newcnst);
1222 : 2 : fprintf (dump_file, "\n");
1223 : : }
1224 : 225712 : local_const_prop_count++;
1225 : 225712 : return true;
1226 : : }
1227 : 67425883 : else if (newreg && newreg != x && try_replace_reg (x, newreg, insn))
1228 : : {
1229 : 1511528 : if (dump_file != NULL)
1230 : : {
1231 : 26 : fprintf (dump_file,
1232 : : "LOCAL COPY-PROP: Replacing reg %d in insn %d",
1233 : 26 : REGNO (x), INSN_UID (insn));
1234 : 26 : fprintf (dump_file, " with reg %d\n", REGNO (newreg));
1235 : : }
1236 : 1511528 : local_copy_prop_count++;
1237 : 1511528 : return true;
1238 : : }
1239 : : }
1240 : : return false;
1241 : : }
1242 : :
1243 : : /* Do local const/copy propagation (i.e. within each basic block). */
1244 : :
1245 : : static bool
1246 : 1457592 : local_cprop_pass (void)
1247 : : {
1248 : 1457592 : basic_block bb;
1249 : 1457592 : rtx_insn *insn;
1250 : 1457592 : bool changed = false;
1251 : 1457592 : unsigned i;
1252 : :
1253 : 1457592 : auto_vec<rtx_insn *> uncond_traps;
1254 : :
1255 : 1457592 : cselib_init (0);
1256 : 28469742 : FOR_EACH_BB_FN (bb, cfun)
1257 : : {
1258 : 325281719 : FOR_BB_INSNS (bb, insn)
1259 : : {
1260 : 298269569 : if (INSN_P (insn))
1261 : : {
1262 : 255797071 : bool was_uncond_trap
1263 : 255797071 : = (GET_CODE (PATTERN (insn)) == TRAP_IF
1264 : 255797071 : && XEXP (PATTERN (insn), 0) == const1_rtx);
1265 : 255797071 : rtx note = find_reg_equal_equiv_note (insn);
1266 : 257534311 : do
1267 : : {
1268 : 257534311 : reg_use_count = 0;
1269 : 257534311 : note_uses (&PATTERN (insn), local_cprop_find_used_regs,
1270 : : NULL);
1271 : 257534311 : if (note)
1272 : 9117366 : local_cprop_find_used_regs (&XEXP (note, 0), NULL);
1273 : :
1274 : 425001184 : for (i = 0; i < reg_use_count; i++)
1275 : : {
1276 : 169204113 : if (do_local_cprop (reg_use_table[i], insn))
1277 : : {
1278 : 1737240 : if (!DEBUG_INSN_P (insn))
1279 : 1697741 : changed = true;
1280 : : break;
1281 : : }
1282 : : }
1283 : 257534311 : if (!was_uncond_trap
1284 : 257523019 : && GET_CODE (PATTERN (insn)) == TRAP_IF
1285 : 257534311 : && XEXP (PATTERN (insn), 0) == const1_rtx)
1286 : : {
1287 : 0 : uncond_traps.safe_push (insn);
1288 : 0 : break;
1289 : : }
1290 : 257534311 : if (insn->deleted ())
1291 : : break;
1292 : : }
1293 : 257534311 : while (i < reg_use_count);
1294 : : }
1295 : 298269569 : cselib_process_insn (insn);
1296 : : }
1297 : :
1298 : : /* Forget everything at the end of a basic block. */
1299 : 27012150 : cselib_clear_table ();
1300 : : }
1301 : :
1302 : 1457592 : cselib_finish ();
1303 : :
1304 : 2915184 : while (!uncond_traps.is_empty ())
1305 : : {
1306 : 0 : rtx_insn *insn = uncond_traps.pop ();
1307 : 0 : basic_block to_split = BLOCK_FOR_INSN (insn);
1308 : 0 : remove_edge (split_block (to_split, insn));
1309 : 0 : emit_barrier_after_bb (to_split);
1310 : : }
1311 : :
1312 : 1457592 : return changed;
1313 : 1457592 : }
1314 : :
1315 : : /* Similar to get_condition, only the resulting condition must be
1316 : : valid at JUMP, instead of at EARLIEST.
1317 : :
1318 : : This differs from noce_get_condition in ifcvt.cc in that we prefer not to
1319 : : settle for the condition variable in the jump instruction being integral.
1320 : : We prefer to be able to record the value of a user variable, rather than
1321 : : the value of a temporary used in a condition. This could be solved by
1322 : : recording the value of *every* register scanned by canonicalize_condition,
1323 : : but this would require some code reorganization. */
1324 : :
1325 : : rtx
1326 : 18798482 : fis_get_condition (rtx_insn *jump)
1327 : : {
1328 : 18798482 : return get_condition (jump, NULL, false, true);
1329 : : }
1330 : :
1331 : : /* Check the comparison COND to see if we can safely form an implicit
1332 : : set from it. */
1333 : :
1334 : : static bool
1335 : 11931510 : implicit_set_cond_p (const_rtx cond)
1336 : : {
1337 : 11931510 : machine_mode mode;
1338 : 11931510 : rtx cst;
1339 : :
1340 : : /* COND must be either an EQ or NE comparison. */
1341 : 11931510 : if (GET_CODE (cond) != EQ && GET_CODE (cond) != NE)
1342 : : return false;
1343 : :
1344 : : /* The first operand of COND must be a register we can propagate. */
1345 : 11939803 : if (!cprop_reg_p (XEXP (cond, 0)))
1346 : : return false;
1347 : :
1348 : : /* The second operand of COND must be a suitable constant. */
1349 : 7892340 : mode = GET_MODE (XEXP (cond, 0));
1350 : 7892340 : cst = XEXP (cond, 1);
1351 : :
1352 : : /* We can't perform this optimization if either operand might be or might
1353 : : contain a signed zero. */
1354 : 7892340 : if (HONOR_SIGNED_ZEROS (mode))
1355 : : {
1356 : : /* It is sufficient to check if CST is or contains a zero. We must
1357 : : handle float, complex, and vector. If any subpart is a zero, then
1358 : : the optimization can't be performed. */
1359 : : /* ??? The complex and vector checks are not implemented yet. We just
1360 : : always return false for them. */
1361 : 0 : if (CONST_DOUBLE_AS_FLOAT_P (cst)
1362 : 6 : && real_equal (CONST_DOUBLE_REAL_VALUE (cst), &dconst0))
1363 : : return false;
1364 : : else
1365 : 6 : return false;
1366 : : }
1367 : :
1368 : 7892334 : return cprop_constant_p (cst);
1369 : : }
1370 : :
1371 : : /* Find the implicit sets of a function. An "implicit set" is a constraint
1372 : : on the value of a variable, implied by a conditional jump. For example,
1373 : : following "if (x == 2)", the then branch may be optimized as though the
1374 : : conditional performed an "explicit set", in this example, "x = 2". This
1375 : : function records the set patterns that are implicit at the start of each
1376 : : basic block.
1377 : :
1378 : : If an implicit set is found but the set is implicit on a critical edge,
1379 : : this critical edge is split.
1380 : :
1381 : : Return true if the CFG was modified, false otherwise. */
1382 : :
1383 : : static bool
1384 : 1457592 : find_implicit_sets (void)
1385 : : {
1386 : 1457592 : basic_block bb, dest;
1387 : 1457592 : rtx cond, new_rtx;
1388 : 1457592 : unsigned int count = 0;
1389 : 1457592 : bool edges_split = false;
1390 : 1457592 : size_t implicit_sets_size = last_basic_block_for_fn (cfun) + 10;
1391 : :
1392 : 1457592 : implicit_sets = XCNEWVEC (rtx, implicit_sets_size);
1393 : :
1394 : 30793554 : FOR_EACH_BB_FN (bb, cfun)
1395 : : {
1396 : : /* Check for more than one successor. */
1397 : 29335962 : if (EDGE_COUNT (bb->succs) <= 1)
1398 : 14964832 : continue;
1399 : :
1400 : 14371130 : cond = fis_get_condition (BB_END (bb));
1401 : :
1402 : : /* If no condition is found or if it isn't of a suitable form,
1403 : : ignore it. */
1404 : 14371130 : if (! cond || ! implicit_set_cond_p (cond))
1405 : 8420885 : continue;
1406 : :
1407 : 11900490 : dest = GET_CODE (cond) == EQ
1408 : 5950245 : ? BRANCH_EDGE (bb)->dest : FALLTHRU_EDGE (bb)->dest;
1409 : :
1410 : : /* If DEST doesn't go anywhere, ignore it. */
1411 : 5950245 : if (! dest || dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
1412 : 0 : continue;
1413 : :
1414 : : /* We have found a suitable implicit set. Try to record it now as
1415 : : a SET in DEST. If DEST has more than one predecessor, the edge
1416 : : between BB and DEST is a critical edge and we must split it,
1417 : : because we can only record one implicit set per DEST basic block. */
1418 : 5950245 : if (! single_pred_p (dest))
1419 : : {
1420 : 2326523 : dest = split_edge (find_edge (bb, dest));
1421 : 2326523 : edges_split = true;
1422 : : }
1423 : :
1424 : 5950245 : if (implicit_sets_size <= (size_t) dest->index)
1425 : : {
1426 : 38709 : size_t old_implicit_sets_size = implicit_sets_size;
1427 : 38709 : implicit_sets_size *= 2;
1428 : 38709 : implicit_sets = XRESIZEVEC (rtx, implicit_sets, implicit_sets_size);
1429 : 38709 : memset (implicit_sets + old_implicit_sets_size, 0,
1430 : 38709 : (implicit_sets_size - old_implicit_sets_size) * sizeof (rtx));
1431 : : }
1432 : :
1433 : 5950245 : new_rtx = gen_rtx_SET (XEXP (cond, 0), XEXP (cond, 1));
1434 : 5950245 : implicit_sets[dest->index] = new_rtx;
1435 : 5950245 : if (dump_file)
1436 : : {
1437 : 42 : fprintf (dump_file, "Implicit set of reg %d in ",
1438 : 42 : REGNO (XEXP (cond, 0)));
1439 : 42 : fprintf (dump_file, "basic block %d\n", dest->index);
1440 : : }
1441 : 5950245 : count++;
1442 : : }
1443 : :
1444 : 1457592 : if (dump_file)
1445 : 63 : fprintf (dump_file, "Found %d implicit sets\n", count);
1446 : :
1447 : : /* Confess our sins. */
1448 : 1457592 : return edges_split;
1449 : : }
1450 : :
1451 : : /* Bypass conditional jumps. */
1452 : :
1453 : : /* The value of last_basic_block at the beginning of the jump_bypass
1454 : : pass. The use of redirect_edge_and_branch_force may introduce new
1455 : : basic blocks, but the data flow analysis is only valid for basic
1456 : : block indices less than bypass_last_basic_block. */
1457 : :
1458 : : static int bypass_last_basic_block;
1459 : :
1460 : : /* Find a set of REGNO to a constant that is available at the end of basic
1461 : : block BB. Return NULL if no such set is found. Based heavily upon
1462 : : find_avail_set. */
1463 : :
1464 : : static struct cprop_expr *
1465 : 1763776 : find_bypass_set (int regno, int bb)
1466 : : {
1467 : 1763776 : struct cprop_expr *result = 0;
1468 : :
1469 : 1952876 : for (;;)
1470 : : {
1471 : 1858326 : rtx src;
1472 : 1858326 : struct cprop_expr *set = lookup_set (regno, &set_hash_table);
1473 : :
1474 : 1858326 : while (set)
1475 : : {
1476 : 2236007 : if (bitmap_bit_p (cprop_avout[bb], set->bitmap_index))
1477 : : break;
1478 : 3795099 : set = next_set (regno, set);
1479 : : }
1480 : :
1481 : 299234 : if (set == 0)
1482 : : break;
1483 : :
1484 : 299234 : src = set->src;
1485 : 299234 : if (cprop_constant_p (src))
1486 : 204684 : result = set;
1487 : :
1488 : 299234 : if (! REG_P (src))
1489 : : break;
1490 : :
1491 : 94550 : regno = REGNO (src);
1492 : 94550 : }
1493 : 1763776 : return result;
1494 : : }
1495 : :
1496 : : /* Subroutine of bypass_block that checks whether a pseudo is killed by
1497 : : any of the instructions inserted on an edge. Jump bypassing places
1498 : : condition code setters on CFG edges using insert_insn_on_edge. This
1499 : : function is required to check that our data flow analysis is still
1500 : : valid prior to commit_edge_insertions. */
1501 : :
1502 : : static bool
1503 : 2383 : reg_killed_on_edge (const_rtx reg, const_edge e)
1504 : : {
1505 : 2383 : rtx_insn *insn;
1506 : :
1507 : 8980 : for (insn = e->insns.r; insn; insn = NEXT_INSN (insn))
1508 : 6597 : if (INSN_P (insn) && reg_set_p (reg, insn))
1509 : : return true;
1510 : :
1511 : : return false;
1512 : : }
1513 : :
1514 : : /* Subroutine of bypass_conditional_jumps that attempts to bypass the given
1515 : : basic block BB which has more than one predecessor. If not NULL, SETCC
1516 : : is the first instruction of BB, which is immediately followed by JUMP_INSN
1517 : : JUMP. Otherwise, SETCC is NULL, and JUMP is the first insn of BB.
1518 : : Returns true if a change was made.
1519 : :
1520 : : During the jump bypassing pass, we may place copies of SETCC instructions
1521 : : on CFG edges. The following routine must be careful to pay attention to
1522 : : these inserted insns when performing its transformations. */
1523 : :
1524 : : static bool
1525 : 756235 : bypass_block (basic_block bb, rtx_insn *setcc, rtx_insn *jump)
1526 : : {
1527 : 756235 : rtx_insn *insn;
1528 : 756235 : rtx note;
1529 : 756235 : edge e, edest;
1530 : 756235 : bool change;
1531 : 756235 : bool may_be_loop_header = false;
1532 : 756235 : bool removed_p;
1533 : 756235 : unsigned i;
1534 : 756235 : edge_iterator ei;
1535 : :
1536 : 756235 : insn = (setcc != NULL) ? setcc : jump;
1537 : :
1538 : : /* Determine set of register uses in INSN. */
1539 : 756235 : reg_use_count = 0;
1540 : 756235 : note_uses (&PATTERN (insn), find_used_regs, NULL);
1541 : 756235 : note = find_reg_equal_equiv_note (insn);
1542 : 756235 : if (note)
1543 : 2934 : find_used_regs (&XEXP (note, 0), NULL);
1544 : :
1545 : 756235 : if (current_loops)
1546 : : {
1547 : : /* If we are to preserve loop structure then do not bypass
1548 : : a loop header. This will either rotate the loop, create
1549 : : multiple entry loops or even irreducible regions. */
1550 : 533812 : if (bb == bb->loop_father->header)
1551 : : return 0;
1552 : : }
1553 : : else
1554 : : {
1555 : 651388 : FOR_EACH_EDGE (e, ei, bb->preds)
1556 : 495151 : if (e->flags & EDGE_DFS_BACK)
1557 : : {
1558 : : may_be_loop_header = true;
1559 : : break;
1560 : : }
1561 : : }
1562 : :
1563 : 629589 : change = false;
1564 : 2164841 : for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
1565 : : {
1566 : 1535252 : removed_p = false;
1567 : :
1568 : 1535252 : if (e->flags & EDGE_COMPLEX)
1569 : : {
1570 : 3620 : ei_next (&ei);
1571 : 3620 : continue;
1572 : : }
1573 : :
1574 : : /* We can't redirect edges from new basic blocks. */
1575 : 1531632 : if (e->src->index >= bypass_last_basic_block)
1576 : : {
1577 : 0 : ei_next (&ei);
1578 : 0 : continue;
1579 : : }
1580 : :
1581 : : /* The irreducible loops created by redirecting of edges entering the
1582 : : loop from outside would decrease effectiveness of some of the
1583 : : following optimizations, so prevent this. */
1584 : 1531632 : if (may_be_loop_header
1585 : 144308 : && !(e->flags & EDGE_DFS_BACK))
1586 : : {
1587 : 70968 : ei_next (&ei);
1588 : 70968 : continue;
1589 : : }
1590 : :
1591 : 3077330 : for (i = 0; i < reg_use_count; i++)
1592 : : {
1593 : 1763776 : rtx reg_used = reg_use_table[i];
1594 : 1763776 : unsigned int regno = REGNO (reg_used);
1595 : 1763776 : basic_block dest, old_dest;
1596 : 1763776 : struct cprop_expr *set;
1597 : 1763776 : rtx src, new_rtx;
1598 : :
1599 : 1763776 : set = find_bypass_set (regno, e->src->index);
1600 : :
1601 : 1763776 : if (! set)
1602 : 1559092 : continue;
1603 : :
1604 : : /* Check the data flow is valid after edge insertions. */
1605 : 204684 : if (e->insns.r && reg_killed_on_edge (reg_used, e))
1606 : 0 : continue;
1607 : :
1608 : 204684 : src = SET_SRC (pc_set (jump));
1609 : :
1610 : 204684 : if (setcc != NULL)
1611 : 204646 : src = simplify_replace_rtx (src,
1612 : 204646 : SET_DEST (PATTERN (setcc)),
1613 : 204646 : SET_SRC (PATTERN (setcc)));
1614 : :
1615 : 204684 : new_rtx = simplify_replace_rtx (src, reg_used, set->src);
1616 : :
1617 : : /* Jump bypassing may have already placed instructions on
1618 : : edges of the CFG. We can't bypass an outgoing edge that
1619 : : has instructions associated with it, as these insns won't
1620 : : get executed if the incoming edge is redirected. */
1621 : 204684 : if (new_rtx == pc_rtx)
1622 : : {
1623 : 74444 : edest = FALLTHRU_EDGE (bb);
1624 : 74444 : dest = edest->insns.r ? NULL : edest->dest;
1625 : : }
1626 : 130240 : else if (GET_CODE (new_rtx) == LABEL_REF)
1627 : : {
1628 : 72673 : dest = BLOCK_FOR_INSN (XEXP (new_rtx, 0));
1629 : : /* Don't bypass edges containing instructions. */
1630 : 72673 : if (dest)
1631 : : {
1632 : 72669 : edest = find_edge (bb, dest);
1633 : 72669 : if (edest && edest->insns.r)
1634 : 57572 : dest = NULL;
1635 : : }
1636 : : }
1637 : : else
1638 : : dest = NULL;
1639 : :
1640 : : /* Avoid unification of the edge with other edges from original
1641 : : branch. We would end up emitting the instruction on "both"
1642 : : edges. */
1643 : 204684 : if (dest && setcc && find_edge (e->src, dest))
1644 : : dest = NULL;
1645 : :
1646 : 204684 : old_dest = e->dest;
1647 : 204684 : if (dest != NULL
1648 : 204684 : && dest != old_dest
1649 : 147110 : && dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
1650 : : {
1651 : 147110 : redirect_edge_and_branch_force (e, dest);
1652 : :
1653 : : /* Copy the register setter to the redirected edge. */
1654 : 147110 : if (setcc)
1655 : : {
1656 : 147096 : rtx pat = PATTERN (setcc);
1657 : 147096 : insert_insn_on_edge (copy_insn (pat), e);
1658 : : }
1659 : :
1660 : 147110 : if (dump_file != NULL)
1661 : : {
1662 : 0 : fprintf (dump_file, "JUMP-BYPASS: Proved reg %d "
1663 : : "in jump_insn %d equals constant ",
1664 : 0 : regno, INSN_UID (jump));
1665 : 0 : print_rtl (dump_file, set->src);
1666 : 0 : fprintf (dump_file, "\n\t when BB %d is entered from "
1667 : : "BB %d. Redirect edge %d->%d to %d.\n",
1668 : 0 : old_dest->index, e->src->index, e->src->index,
1669 : : old_dest->index, dest->index);
1670 : : }
1671 : : change = true;
1672 : : removed_p = true;
1673 : : break;
1674 : : }
1675 : : }
1676 : 1460664 : if (!removed_p)
1677 : 1313554 : ei_next (&ei);
1678 : : }
1679 : : return change;
1680 : : }
1681 : :
1682 : : /* Find basic blocks with more than one predecessor that only contain a
1683 : : single conditional jump. If the result of the comparison is known at
1684 : : compile-time from any incoming edge, redirect that edge to the
1685 : : appropriate target. Return nonzero if a change was made.
1686 : :
1687 : : This function is now mis-named, because we also handle indirect jumps. */
1688 : :
1689 : : static bool
1690 : 1311293 : bypass_conditional_jumps (void)
1691 : : {
1692 : 1311293 : basic_block bb;
1693 : 1311293 : bool changed;
1694 : 1311293 : rtx_insn *setcc;
1695 : 1311293 : rtx_insn *insn;
1696 : 1311293 : rtx dest;
1697 : :
1698 : : /* Note we start at block 1. */
1699 : 1311293 : if (ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
1700 : : return false;
1701 : :
1702 : 1311293 : mark_dfs_back_edges ();
1703 : :
1704 : 1311293 : changed = false;
1705 : 28675137 : FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->next_bb,
1706 : : EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb)
1707 : : {
1708 : : /* Check for more than one predecessor. */
1709 : 27363844 : if (!single_pred_p (bb))
1710 : : {
1711 : 7291300 : setcc = NULL;
1712 : 50991469 : FOR_BB_INSNS (bb, insn)
1713 : 50258236 : if (DEBUG_INSN_P (insn))
1714 : 24907367 : continue;
1715 : 25350869 : else if (NONJUMP_INSN_P (insn))
1716 : : {
1717 : 9604948 : if (setcc)
1718 : : break;
1719 : 6787292 : if (GET_CODE (PATTERN (insn)) != SET)
1720 : : break;
1721 : :
1722 : 5293184 : dest = SET_DEST (PATTERN (insn));
1723 : 5293184 : if (REG_P (dest))
1724 : : setcc = insn;
1725 : : else
1726 : : break;
1727 : : }
1728 : 15745921 : else if (JUMP_P (insn))
1729 : : {
1730 : 756502 : if ((any_condjump_p (insn) || computed_jump_p (insn))
1731 : 756451 : && onlyjump_p (insn))
1732 : 756235 : if (bypass_block (bb, setcc, insn))
1733 : 27363844 : changed = true;
1734 : : break;
1735 : : }
1736 : 14989629 : else if (INSN_P (insn))
1737 : : break;
1738 : : }
1739 : : }
1740 : :
1741 : : /* If we bypassed any register setting insns, we inserted a
1742 : : copy on the redirected edge. These need to be committed. */
1743 : 1311293 : if (changed)
1744 : 42640 : commit_edge_insertions ();
1745 : :
1746 : : return changed;
1747 : : }
1748 : :
1749 : : /* Main function for the CPROP pass. */
1750 : :
1751 : : static bool
1752 : 2786619 : one_cprop_pass (void)
1753 : : {
1754 : 2786619 : bool changed = false;
1755 : 2786619 : int i;
1756 : :
1757 : : /* Return if there's nothing to do, or it is too expensive. */
1758 : 2786619 : if (n_basic_blocks_for_fn (cfun) <= NUM_FIXED_BLOCKS + 1
1759 : 2786619 : || gcse_or_cprop_is_too_expensive (_ ("const/copy propagation disabled")))
1760 : 1329027 : return false;
1761 : :
1762 : 1457592 : global_const_prop_count = local_const_prop_count = 0;
1763 : 1457592 : global_copy_prop_count = local_copy_prop_count = 0;
1764 : :
1765 : 1457592 : bytes_used = 0;
1766 : 1457592 : gcc_obstack_init (&cprop_obstack);
1767 : :
1768 : : /* Do a local const/copy propagation pass first. The global pass
1769 : : only handles global opportunities.
1770 : : If the local pass changes something, remove any unreachable blocks
1771 : : because the CPROP global dataflow analysis may get into infinite
1772 : : loops for CFGs with unreachable blocks.
1773 : :
1774 : : FIXME: This local pass should not be necessary after CSE (but for
1775 : : some reason it still is). It is also (proven) not necessary
1776 : : to run the local pass right after FWPWOP.
1777 : :
1778 : : FIXME: The global analysis would not get into infinite loops if it
1779 : : would use the DF solver (via df_simple_dataflow) instead of
1780 : : the solver implemented in this file. */
1781 : 1457592 : if (local_cprop_pass ())
1782 : 216184 : changed = true;
1783 : :
1784 : 216184 : if (changed)
1785 : 216184 : delete_unreachable_blocks ();
1786 : :
1787 : : /* Determine implicit sets. This may change the CFG (split critical
1788 : : edges if that exposes an implicit set).
1789 : : Note that find_implicit_sets() does not rely on up-to-date DF caches
1790 : : so that we do not have to re-run df_analyze() even if local CPROP
1791 : : changed something.
1792 : : ??? This could run earlier so that any uncovered implicit sets
1793 : : sets could be exploited in local_cprop_pass() also. Later. */
1794 : 1457592 : if (find_implicit_sets ())
1795 : : changed = true;
1796 : :
1797 : : /* If local_cprop_pass() or find_implicit_sets() changed something,
1798 : : run df_analyze() to bring all insn caches up-to-date, and to take
1799 : : new basic blocks from edge splitting on the DF radar.
1800 : : NB: This also runs the fast DCE pass, because execute_rtl_cprop
1801 : : sets DF_LR_RUN_DCE. */
1802 : 887361 : if (changed)
1803 : 660650 : df_analyze ();
1804 : :
1805 : : /* Initialize implicit_set_indexes array. */
1806 : 1457592 : implicit_set_indexes = XNEWVEC (int, last_basic_block_for_fn (cfun));
1807 : 35052412 : for (i = 0; i < last_basic_block_for_fn (cfun); i++)
1808 : 33594820 : implicit_set_indexes[i] = -1;
1809 : :
1810 : 1457592 : alloc_hash_table (&set_hash_table);
1811 : 1457592 : compute_hash_table (&set_hash_table);
1812 : :
1813 : : /* Free implicit_sets before peak usage. */
1814 : 1457592 : free (implicit_sets);
1815 : 1457592 : implicit_sets = NULL;
1816 : :
1817 : 1457592 : if (dump_file)
1818 : 63 : dump_hash_table (dump_file, "SET", &set_hash_table);
1819 : 1457592 : if (set_hash_table.n_elems > 0)
1820 : : {
1821 : 1311293 : basic_block bb;
1822 : 1311293 : auto_vec<rtx_insn *> uncond_traps;
1823 : :
1824 : 1311293 : alloc_cprop_mem (last_basic_block_for_fn (cfun),
1825 : : set_hash_table.n_elems);
1826 : 1311293 : compute_cprop_data ();
1827 : :
1828 : 1311293 : free (implicit_set_indexes);
1829 : 1311293 : implicit_set_indexes = NULL;
1830 : :
1831 : : /* Allocate vars to track sets of regs. */
1832 : 1311293 : reg_set_bitmap = ALLOC_REG_SET (NULL);
1833 : :
1834 : 28675137 : FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->next_bb,
1835 : : EXIT_BLOCK_PTR_FOR_FN (cfun),
1836 : : next_bb)
1837 : : {
1838 : 27363844 : bool seen_uncond_trap = false;
1839 : 27363844 : rtx_insn *insn;
1840 : :
1841 : : /* Reset tables used to keep track of what's still valid [since
1842 : : the start of the block]. */
1843 : 27363844 : reset_opr_set_tables ();
1844 : :
1845 : 299530384 : FOR_BB_INSNS (bb, insn)
1846 : 272166540 : if (INSN_P (insn))
1847 : : {
1848 : 229440433 : bool was_uncond_trap
1849 : 229440433 : = (GET_CODE (PATTERN (insn)) == TRAP_IF
1850 : 229440433 : && XEXP (PATTERN (insn), 0) == const1_rtx);
1851 : :
1852 : 229440433 : if (cprop_insn (insn))
1853 : 674192 : changed = true;
1854 : :
1855 : : /* Keep track of everything modified by this insn. */
1856 : : /* ??? Need to be careful w.r.t. mods done to INSN.
1857 : : Don't call mark_oprs_set if we turned the
1858 : : insn into a NOTE, or deleted the insn. */
1859 : 229440433 : if (! NOTE_P (insn) && ! insn->deleted ())
1860 : 229440433 : mark_oprs_set (insn);
1861 : :
1862 : 229440433 : if (!was_uncond_trap
1863 : 229430525 : && GET_CODE (PATTERN (insn)) == TRAP_IF
1864 : 229440433 : && XEXP (PATTERN (insn), 0) == const1_rtx)
1865 : : {
1866 : : /* If we have already seen an unconditional trap
1867 : : earlier, the rest of the bb is going to be removed
1868 : : as unreachable. Just turn it into a note, so that
1869 : : RTL verification doesn't complain about it before
1870 : : it is finally removed. */
1871 : 0 : if (seen_uncond_trap)
1872 : 0 : set_insn_deleted (insn);
1873 : : else
1874 : : {
1875 : 0 : seen_uncond_trap = true;
1876 : 0 : uncond_traps.safe_push (insn);
1877 : : }
1878 : : }
1879 : : }
1880 : : }
1881 : :
1882 : : /* Make sure bypass_conditional_jumps will ignore not just its new
1883 : : basic blocks, but also the ones after unconditional traps (those are
1884 : : unreachable and will be eventually removed as such). */
1885 : 1311293 : bypass_last_basic_block = last_basic_block_for_fn (cfun);
1886 : :
1887 : 1311293 : while (!uncond_traps.is_empty ())
1888 : : {
1889 : 0 : rtx_insn *insn = uncond_traps.pop ();
1890 : 0 : basic_block to_split = BLOCK_FOR_INSN (insn);
1891 : 0 : remove_edge (split_block (to_split, insn));
1892 : 0 : emit_barrier_after_bb (to_split);
1893 : : }
1894 : :
1895 : 1311293 : if (bypass_conditional_jumps ())
1896 : 42640 : changed = true;
1897 : :
1898 : 1311293 : FREE_REG_SET (reg_set_bitmap);
1899 : 1311293 : free_cprop_mem ();
1900 : 1311293 : }
1901 : : else
1902 : : {
1903 : 146299 : free (implicit_set_indexes);
1904 : 146299 : implicit_set_indexes = NULL;
1905 : : }
1906 : :
1907 : 1457592 : free_hash_table (&set_hash_table);
1908 : 1457592 : obstack_free (&cprop_obstack, NULL);
1909 : :
1910 : 1457592 : if (dump_file)
1911 : : {
1912 : 63 : fprintf (dump_file, "CPROP of %s, %d basic blocks, %d bytes needed, ",
1913 : 63 : current_function_name (), n_basic_blocks_for_fn (cfun),
1914 : : bytes_used);
1915 : 63 : fprintf (dump_file, "%d local const props, %d local copy props, ",
1916 : : local_const_prop_count, local_copy_prop_count);
1917 : 63 : fprintf (dump_file, "%d global const props, %d global copy props\n\n",
1918 : : global_const_prop_count, global_copy_prop_count);
1919 : : }
1920 : :
1921 : : return changed;
1922 : : }
1923 : :
1924 : : /* All the passes implemented in this file. Each pass has its
1925 : : own gate and execute function, and at the end of the file a
1926 : : pass definition for passes.cc.
1927 : :
1928 : : We do not construct an accurate cfg in functions which call
1929 : : setjmp, so none of these passes runs if the function calls
1930 : : setjmp.
1931 : : FIXME: Should just handle setjmp via REG_SETJMP notes. */
1932 : :
1933 : : static unsigned int
1934 : 2786619 : execute_rtl_cprop (void)
1935 : : {
1936 : 2786619 : int changed;
1937 : 2786619 : delete_unreachable_blocks ();
1938 : 2786619 : df_set_flags (DF_LR_RUN_DCE);
1939 : 2786619 : df_analyze ();
1940 : 2786619 : changed = one_cprop_pass ();
1941 : 2786619 : flag_rerun_cse_after_global_opts |= changed;
1942 : 2786619 : if (changed)
1943 : 693969 : cleanup_cfg (CLEANUP_CFG_CHANGED);
1944 : 2786619 : return 0;
1945 : : }
1946 : :
1947 : : namespace {
1948 : :
1949 : : const pass_data pass_data_rtl_cprop =
1950 : : {
1951 : : RTL_PASS, /* type */
1952 : : "cprop", /* name */
1953 : : OPTGROUP_NONE, /* optinfo_flags */
1954 : : TV_CPROP, /* tv_id */
1955 : : PROP_cfglayout, /* properties_required */
1956 : : 0, /* properties_provided */
1957 : : 0, /* properties_destroyed */
1958 : : 0, /* todo_flags_start */
1959 : : TODO_df_finish, /* todo_flags_finish */
1960 : : };
1961 : :
1962 : : class pass_rtl_cprop : public rtl_opt_pass
1963 : : {
1964 : : public:
1965 : 848859 : pass_rtl_cprop (gcc::context *ctxt)
1966 : 1697718 : : rtl_opt_pass (pass_data_rtl_cprop, ctxt)
1967 : : {}
1968 : :
1969 : : /* opt_pass methods: */
1970 : 565906 : opt_pass * clone () final override { return new pass_rtl_cprop (m_ctxt); }
1971 : 4299327 : bool gate (function *fun) final override
1972 : : {
1973 : 3015057 : return optimize > 0 && flag_gcse
1974 : 2788608 : && !fun->calls_setjmp
1975 : 7085949 : && dbg_cnt (cprop);
1976 : : }
1977 : :
1978 : 2786619 : unsigned int execute (function *) final override
1979 : : {
1980 : 2786619 : return execute_rtl_cprop ();
1981 : : }
1982 : :
1983 : : }; // class pass_rtl_cprop
1984 : :
1985 : : } // anon namespace
1986 : :
1987 : : rtl_opt_pass *
1988 : 282953 : make_pass_rtl_cprop (gcc::context *ctxt)
1989 : : {
1990 : 282953 : return new pass_rtl_cprop (ctxt);
1991 : : }
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