Line data Source code
1 : /* Global constant/copy propagation for RTL.
2 : Copyright (C) 1997-2026 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 31278408 : cprop_alloc (unsigned long size)
141 : {
142 31278408 : bytes_used += size;
143 31278408 : 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 71214272 : reg_available_p (const_rtx x, const rtx_insn *insn ATTRIBUTE_UNUSED)
151 : {
152 2757427 : 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 117766611 : hash_mod (int regno, int hash_table_size)
164 : {
165 117766611 : 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 16570780 : insert_set_in_table (rtx dest, rtx src, rtx_insn *insn,
176 : struct hash_table_d *table, bool implicit)
177 : {
178 16570780 : bool found = false;
179 16570780 : unsigned int hash;
180 16570780 : struct cprop_expr *cur_expr, *last_expr = NULL;
181 16570780 : struct cprop_occr *cur_occr;
182 :
183 16570780 : hash = hash_mod (REGNO (dest), table->size);
184 :
185 39152055 : for (cur_expr = table->table[hash]; cur_expr;
186 22581275 : cur_expr = cur_expr->next_same_hash)
187 : {
188 24444427 : if (dest == cur_expr->dest
189 23908820 : && src == cur_expr->src)
190 : {
191 : found = true;
192 : break;
193 : }
194 22581275 : last_expr = cur_expr;
195 : }
196 :
197 16570780 : if (! found)
198 : {
199 14707628 : cur_expr = GOBNEW (struct cprop_expr);
200 14707628 : bytes_used += sizeof (struct cprop_expr);
201 14707628 : if (table->table[hash] == NULL)
202 : /* This is the first pattern that hashed to this index. */
203 11705450 : table->table[hash] = cur_expr;
204 : else
205 : /* Add EXPR to end of this hash chain. */
206 3002178 : 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 14707628 : cur_expr->dest = copy_rtx (dest);
212 14707628 : cur_expr->src = copy_rtx (src);
213 14707628 : cur_expr->bitmap_index = table->n_elems++;
214 14707628 : cur_expr->next_same_hash = NULL;
215 14707628 : cur_expr->avail_occr = NULL;
216 : }
217 :
218 : /* Now record the occurrence. */
219 16570780 : cur_occr = cur_expr->avail_occr;
220 :
221 16570780 : if (cur_occr
222 16570780 : && 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 16570780 : cur_occr = GOBNEW (struct cprop_occr);
234 16570780 : bytes_used += sizeof (struct cprop_occr);
235 16570780 : cur_occr->insn = insn;
236 16570780 : cur_occr->next = cur_expr->avail_occr;
237 16570780 : cur_expr->avail_occr = cur_occr;
238 : }
239 :
240 : /* Record bitmap_index of the implicit set in implicit_set_indexes. */
241 16570780 : if (implicit)
242 6473123 : implicit_set_indexes[BLOCK_FOR_INSN (insn)->index]
243 6473123 : = cur_expr->bitmap_index;
244 16570780 : }
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 219876306 : cprop_constant_p (const_rtx x)
252 : {
253 219876306 : 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 563093628 : cprop_reg_p (const_rtx x)
261 : {
262 415175418 : 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 152663257 : hash_scan_set (rtx set, rtx_insn *insn, struct hash_table_d *table,
270 : bool implicit)
271 : {
272 152663257 : rtx src = SET_SRC (set);
273 152663257 : rtx dest = SET_DEST (set);
274 :
275 221120102 : if (cprop_reg_p (dest)
276 68456845 : && reg_available_p (dest, insn)
277 67872293 : && 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 67872293 : rtx note = find_reg_equal_equiv_note (insn);
293 67872293 : if (note != 0
294 4442921 : && REG_NOTE_KIND (note) == REG_EQUAL
295 4004798 : && !REG_P (src)
296 71573458 : && cprop_constant_p (XEXP (note, 0)))
297 1741933 : src = XEXP (note, 0), set = gen_rtx_SET (dest, src);
298 :
299 : /* Record sets for constant/copy propagation. */
300 67872293 : if ((cprop_reg_p (src)
301 2757427 : && src != dest
302 2757427 : && reg_available_p (src, insn))
303 65271076 : || cprop_constant_p (src))
304 16570780 : insert_set_in_table (dest, src, insn, table, implicit);
305 : }
306 152663257 : }
307 :
308 : /* Process INSN and add hash table entries as appropriate. */
309 :
310 : static void
311 153389774 : hash_scan_insn (rtx_insn *insn, struct hash_table_d *table)
312 : {
313 153389774 : rtx pat = PATTERN (insn);
314 153389774 : int i;
315 :
316 : /* Pick out the sets of INSN and for other forms of instructions record
317 : what's been modified. */
318 :
319 153389774 : if (GET_CODE (pat) == SET)
320 121509611 : hash_scan_set (pat, insn, table, false);
321 31880163 : else if (GET_CODE (pat) == PARALLEL)
322 72682461 : for (i = 0; i < XVECLEN (pat, 0); i++)
323 : {
324 48790816 : rtx x = XVECEXP (pat, 0, i);
325 :
326 48790816 : if (GET_CODE (x) == SET)
327 24603147 : hash_scan_set (x, insn, table, false);
328 : }
329 153389774 : }
330 :
331 : /* Dump the hash table TABLE to file FILE under the name NAME. */
332 :
333 : static void
334 64 : dump_hash_table (FILE *file, const char *name, struct hash_table_d *table)
335 : {
336 64 : int i;
337 : /* Flattened out table, so it's printed in proper order. */
338 64 : struct cprop_expr **flat_table;
339 64 : unsigned int *hash_val;
340 64 : struct cprop_expr *expr;
341 :
342 64 : flat_table = XCNEWVEC (struct cprop_expr *, table->n_elems);
343 64 : hash_val = XNEWVEC (unsigned int, table->n_elems);
344 :
345 1354 : for (i = 0; i < (int) table->size; i++)
346 1361 : for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash)
347 : {
348 135 : flat_table[expr->bitmap_index] = expr;
349 135 : hash_val[expr->bitmap_index] = i;
350 : }
351 :
352 64 : fprintf (file, "%s hash table (%d buckets, %d entries)\n",
353 : name, table->size, table->n_elems);
354 :
355 263 : for (i = 0; i < (int) table->n_elems; i++)
356 135 : if (flat_table[i] != 0)
357 : {
358 135 : expr = flat_table[i];
359 135 : fprintf (file, "Index %d (hash value %d)\n ",
360 135 : expr->bitmap_index, hash_val[i]);
361 135 : print_rtl (file, expr->dest);
362 135 : fprintf (file, " := ");
363 135 : print_rtl (file, expr->src);
364 135 : fprintf (file, "\n");
365 : }
366 :
367 64 : fprintf (file, "\n");
368 :
369 64 : free (flat_table);
370 64 : free (hash_val);
371 64 : }
372 :
373 : /* Record as unavailable all registers that are DEF operands of INSN. */
374 :
375 : static void
376 153389774 : make_set_regs_unavailable (rtx_insn *insn)
377 : {
378 153389774 : df_ref def;
379 :
380 1300958886 : FOR_EACH_INSN_DEF (def, insn)
381 1147569112 : SET_REGNO_REG_SET (reg_set_bitmap, DF_REF_REGNO (def));
382 153389774 : }
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 1548784 : compute_hash_table_work (struct hash_table_d *table)
397 : {
398 1548784 : basic_block bb;
399 :
400 : /* Allocate vars to track sets of regs. */
401 1548784 : reg_set_bitmap = ALLOC_REG_SET (NULL);
402 :
403 34118751 : FOR_EACH_BB_FN (bb, cfun)
404 : {
405 32569967 : 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 32569967 : 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 395912996 : FOR_BB_INSNS_REVERSE (bb, insn)
415 : {
416 : /* Only real insns are interesting. */
417 363343029 : if (!NONDEBUG_INSN_P (insn))
418 209953255 : continue;
419 :
420 : /* Record interesting sets from INSN in the hash table. */
421 153389774 : hash_scan_insn (insn, table);
422 :
423 : /* Any registers set in INSN will make SETs above it not AVAIL. */
424 153389774 : 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 32569967 : if (implicit_sets[bb->index] != NULL_RTX)
430 6550499 : hash_scan_set (implicit_sets[bb->index], BB_HEAD (bb), table, true);
431 : }
432 :
433 1548784 : FREE_REG_SET (reg_set_bitmap);
434 1548784 : }
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 1548784 : alloc_hash_table (struct hash_table_d *table)
441 : {
442 1548784 : int n;
443 :
444 1548784 : n = get_max_insn_count ();
445 :
446 1548784 : table->size = n / 4;
447 1548784 : if (table->size < 11)
448 567422 : 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 1548784 : table->size |= 1;
454 1548784 : n = table->size * sizeof (struct cprop_expr *);
455 1548784 : table->table = XNEWVAR (struct cprop_expr *, n);
456 1548784 : }
457 :
458 : /* Free things allocated by alloc_hash_table. */
459 :
460 : static void
461 1548784 : free_hash_table (struct hash_table_d *table)
462 : {
463 1548784 : 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 1548784 : compute_hash_table (struct hash_table_d *table)
471 : {
472 : /* Initialize count of number of entries in hash table. */
473 1548784 : table->n_elems = 0;
474 1548784 : memset (table->table, 0, table->size * sizeof (struct cprop_expr *));
475 :
476 1548784 : compute_hash_table_work (table);
477 1548784 : }
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 101195831 : lookup_set (unsigned int regno, struct hash_table_d *table)
486 : {
487 101195831 : unsigned int hash = hash_mod (regno, table->size);
488 101195831 : struct cprop_expr *expr;
489 :
490 101195831 : expr = table->table[hash];
491 :
492 109662865 : while (expr && REGNO (expr->dest) != regno)
493 8467034 : expr = expr->next_same_hash;
494 :
495 101195831 : 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 44211828 : do
504 44211828 : expr = expr->next_same_hash;
505 87509594 : 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 30487069 : 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 176518358 : 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 283140963 : mark_oprs_set (rtx_insn *insn)
535 : {
536 283140963 : df_ref def;
537 :
538 1312609482 : FOR_EACH_INSN_DEF (def, insn)
539 1029468519 : SET_REGNO_REG_SET (reg_set_bitmap, DF_REF_REGNO (def));
540 283140963 : }
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 1396900 : alloc_cprop_mem (int n_blocks, int n_sets)
557 : {
558 1396900 : cprop_avloc = sbitmap_vector_alloc (n_blocks, n_sets);
559 1396900 : cprop_kill = sbitmap_vector_alloc (n_blocks, n_sets);
560 :
561 1396900 : cprop_avin = sbitmap_vector_alloc (n_blocks, n_sets);
562 1396900 : cprop_avout = sbitmap_vector_alloc (n_blocks, n_sets);
563 1396900 : }
564 :
565 : /* Free vars used by copy/const propagation. */
566 :
567 : static void
568 1396900 : free_cprop_mem (void)
569 : {
570 1396900 : sbitmap_vector_free (cprop_avloc);
571 1396900 : sbitmap_vector_free (cprop_kill);
572 1396900 : sbitmap_vector_free (cprop_avin);
573 1396900 : sbitmap_vector_free (cprop_avout);
574 1396900 : }
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 1396900 : compute_local_properties (sbitmap *kill, sbitmap *comp,
592 : struct hash_table_d *table)
593 : {
594 1396900 : unsigned int i;
595 :
596 : /* Initialize the bitmaps that were passed in. */
597 1396900 : bitmap_vector_clear (kill, last_basic_block_for_fn (cfun));
598 1396900 : bitmap_vector_clear (comp, last_basic_block_for_fn (cfun));
599 :
600 70614626 : for (i = 0; i < table->size; i++)
601 : {
602 67820826 : struct cprop_expr *expr;
603 :
604 82528454 : for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash)
605 : {
606 14707628 : int indx = expr->bitmap_index;
607 14707628 : df_ref def;
608 14707628 : 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 14707628 : for (def = DF_REG_DEF_CHAIN (REGNO (expr->dest));
613 81731739 : def; def = DF_REF_NEXT_REG (def))
614 67024111 : 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 14707628 : if (REG_P (expr->src))
619 2389305 : for (def = DF_REG_DEF_CHAIN (REGNO (expr->src));
620 6749240 : def; def = DF_REF_NEXT_REG (def))
621 4359935 : 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 31278408 : for (occr = expr->avail_occr; occr != NULL; occr = occr->next)
626 : {
627 16570780 : bitmap_set_bit (comp[BLOCK_FOR_INSN (occr->insn)->index], indx);
628 : }
629 : }
630 : }
631 1396900 : }
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 1396900 : compute_cprop_data (void)
640 : {
641 1396900 : basic_block bb;
642 :
643 1396900 : compute_local_properties (cprop_kill, cprop_avloc, &set_hash_table);
644 1396900 : 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 33280869 : FOR_EACH_BB_FN (bb, cfun)
652 : {
653 31883969 : int index = implicit_set_indexes[bb->index];
654 31883969 : if (index != -1)
655 6473123 : bitmap_set_bit (cprop_avin[bb->index], index);
656 : }
657 1396900 : }
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 1223415311 : find_used_regs (rtx *xptr, void *data ATTRIBUTE_UNUSED)
680 : {
681 1223415311 : int i, j;
682 1223415311 : enum rtx_code code;
683 1223415311 : const char *fmt;
684 1223415311 : 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 1705107584 : repeat:
689 1705107584 : if (x == 0)
690 : return;
691 :
692 1705107584 : code = GET_CODE (x);
693 1705107584 : if (REG_P (x))
694 : {
695 371609925 : if (reg_use_count == MAX_USES)
696 : return;
697 :
698 371584423 : reg_use_table[reg_use_count] = x;
699 371584423 : reg_use_count++;
700 : }
701 :
702 : /* Recursively scan the operands of this expression. */
703 :
704 3526562054 : for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
705 : {
706 2303172245 : 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 1023022356 : if (i == 0)
712 : {
713 481692273 : x = XEXP (x, 0);
714 481692273 : goto repeat;
715 : }
716 :
717 541330083 : find_used_regs (&XEXP (x, i), data);
718 : }
719 1280149889 : else if (fmt[i] == 'E')
720 34250915 : for (j = 0; j < XVECLEN (x, i); j++)
721 24930173 : 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 7998137 : try_replace_reg (rtx from, rtx to, rtx_insn *insn)
730 : {
731 7998137 : rtx note = find_reg_equal_equiv_note (insn);
732 7998137 : rtx src = 0;
733 7998137 : bool success = false;
734 7998137 : rtx set = single_set (insn);
735 :
736 7998137 : bool check_rtx_costs = true;
737 7998137 : bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn));
738 7998137 : int old_cost = set ? set_rtx_cost (set, speed) : 0;
739 :
740 7416675 : if (!set
741 7416675 : || CONSTANT_P (SET_SRC (set))
742 7383095 : || (note != 0
743 2813752 : && REG_NOTE_KIND (note) == REG_EQUAL
744 2813752 : && (GET_CODE (XEXP (note, 0)) == CONST
745 2803348 : || 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 7998137 : to = copy_rtx (to);
752 :
753 7998137 : 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 7998137 : if (check_rtx_costs
760 6529881 : && CONSTANT_P (to)
761 12351207 : && set_rtx_cost (set, speed) > old_cost)
762 : {
763 3080369 : cancel_changes (0);
764 3080369 : return false;
765 : }
766 :
767 :
768 4917768 : if (num_changes_pending () && apply_change_group ())
769 : success = true;
770 :
771 : /* Try to simplify SET_SRC if we have substituted a constant. */
772 4917768 : if (success && set && CONSTANT_P (to))
773 : {
774 375405 : src = simplify_rtx (SET_SRC (set));
775 :
776 375405 : if (src)
777 6364 : 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 4917768 : if (note != 0 && REG_NOTE_KIND (note) == REG_EQUAL)
783 2269470 : set_unique_reg_note (insn, REG_EQUAL,
784 : simplify_replace_rtx (XEXP (note, 0), from, to));
785 4917768 : 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 1655350 : src = simplify_replace_rtx (SET_SRC (set), from, to);
791 :
792 1655350 : if (!rtx_equal_p (src, SET_SRC (set))
793 1655350 : && 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 169908 : if (!success && note == 0 && set != 0 && REG_P (SET_DEST (set))
800 1821864 : && !contains_paradoxical_subreg_p (SET_SRC (set)))
801 149828 : note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src));
802 : }
803 :
804 4917768 : 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 3601 : rtx dest = simplify_replace_rtx (SET_DEST (set), from, to);
810 :
811 3601 : if (!rtx_equal_p (dest, SET_DEST (set))
812 3601 : && 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 4917768 : 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 98252809 : find_avail_set (int regno, rtx_insn *insn, struct cprop_expr *set_ret[2])
833 : {
834 98252809 : 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 99620079 : while (1)
846 : {
847 98936444 : rtx src;
848 98936444 : 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 98936444 : while (set)
853 : {
854 43184176 : if (bitmap_bit_p (cprop_avin[BLOCK_FOR_INSN (insn)->index],
855 : set->bitmap_index))
856 : break;
857 139884930 : 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 2235690 : if (set == 0)
863 : break;
864 :
865 2235690 : 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 2235690 : if (cprop_constant_p (src))
875 1552055 : set_ret[1] = set;
876 683635 : else if (reg_not_set_p (src, insn))
877 679219 : 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 2235690 : 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 683635 : regno = REGNO (src);
887 683635 : }
888 98252809 : }
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 628638 : cprop_jump (basic_block bb, rtx_insn *setcc, rtx_insn *jump, rtx from, rtx src)
899 : {
900 628638 : rtx new_rtx, set_src, note_src;
901 628638 : rtx set = pc_set (jump);
902 628638 : rtx note = find_reg_equal_equiv_note (jump);
903 :
904 628638 : 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 628638 : 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 628638 : if (setcc != NULL_RTX
918 628638 : && !modified_between_p (from, setcc, jump)
919 1257276 : && !modified_between_p (src, setcc, jump))
920 : {
921 628638 : rtx setcc_src;
922 628638 : rtx setcc_set = single_set (setcc);
923 628638 : rtx setcc_note = find_reg_equal_equiv_note (setcc);
924 628638 : setcc_src = (setcc_note && GET_CODE (XEXP (setcc_note, 0)) != EXPR_LIST)
925 628638 : ? XEXP (setcc_note, 0) : SET_SRC (setcc_set);
926 628638 : set_src = simplify_replace_rtx (set_src, SET_DEST (setcc_set),
927 : setcc_src);
928 : }
929 : else
930 : setcc = NULL;
931 :
932 628638 : new_rtx = simplify_replace_rtx (set_src, from, src);
933 :
934 : /* If no simplification can be made, then try the next register. */
935 628638 : 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 625210 : if (new_rtx == pc_rtx)
940 2508 : 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 622702 : if (setcc && modified_in_p (new_rtx, setcc))
946 : return false;
947 1605 : 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 : return false;
961 : }
962 :
963 : /* Remove REG_EQUAL note after simplification. */
964 1605 : if (note_src)
965 0 : remove_note (jump, note);
966 : }
967 :
968 4113 : global_const_prop_count++;
969 4113 : 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 4113 : 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 4113 : if (new_rtx != pc_rtx && simplejump_p (jump))
983 : {
984 1605 : edge e;
985 1605 : edge_iterator ei;
986 :
987 1605 : FOR_EACH_EDGE (e, ei, bb->succs)
988 1605 : if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
989 1605 : && BB_HEAD (e->dest) == JUMP_LABEL (jump))
990 : {
991 1605 : e->flags |= EDGE_FALLTHRU;
992 1605 : break;
993 : }
994 1605 : 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 5671125 : constprop_register (rtx from, rtx src, rtx_insn *insn)
1006 : {
1007 5671125 : rtx sset;
1008 5671125 : rtx_insn *next_insn;
1009 :
1010 : /* Check for reg setting instructions followed by conditional branch
1011 : instructions first. */
1012 5671125 : if ((sset = single_set (insn)) != NULL
1013 5179654 : && (next_insn = next_nondebug_insn (insn)) != NULL
1014 5177165 : && any_condjump_p (next_insn)
1015 6299769 : && onlyjump_p (next_insn))
1016 : {
1017 628644 : rtx dest = SET_DEST (sset);
1018 628644 : if (REG_P (dest)
1019 628644 : && cprop_jump (BLOCK_FOR_INSN (insn), insn, next_insn,
1020 : from, src))
1021 : return true;
1022 : }
1023 :
1024 : /* Handle normal insns next. */
1025 5667012 : 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 5277997 : 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 283140963 : cprop_insn (rtx_insn *insn)
1044 : {
1045 283140963 : unsigned i;
1046 283140963 : int changed_this_round;
1047 283140963 : bool changed = false;
1048 283949437 : rtx note;
1049 :
1050 283949437 : do
1051 : {
1052 283949437 : changed_this_round = 0;
1053 283949437 : reg_use_count = 0;
1054 283949437 : note_uses (&PATTERN (insn), find_used_regs, NULL);
1055 :
1056 : /* We may win even when propagating constants into notes. */
1057 283949437 : note = find_reg_equal_equiv_note (insn);
1058 283949437 : if (note)
1059 7380733 : find_used_regs (&XEXP (note, 0), NULL);
1060 :
1061 459784160 : for (i = 0; i < reg_use_count; i++)
1062 : {
1063 175834723 : rtx reg_used = reg_use_table[i];
1064 175834723 : unsigned int regno = REGNO (reg_used);
1065 175834723 : rtx src_cst = NULL, src_reg = NULL;
1066 175834723 : 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 175834723 : if (! reg_not_set_p (reg_used, insn))
1071 77581914 : continue;
1072 :
1073 : /* Find an assignment that sets reg_used and is available
1074 : at the start of the block. */
1075 98252809 : find_avail_set (regno, insn, set);
1076 98252809 : if (set[0])
1077 678633 : src_reg = set[0]->src;
1078 98252809 : if (set[1])
1079 1552055 : src_cst = set[1]->src;
1080 :
1081 : /* Constant propagation. */
1082 1552055 : if (src_cst && cprop_constant_p (src_cst)
1083 3104110 : && constprop_register (reg_used, src_cst, insn))
1084 : {
1085 155446 : changed = true;
1086 155446 : changed_this_round = 1;
1087 155446 : global_const_prop_count++;
1088 155446 : 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 155446 : if (insn->deleted ())
1098 0 : return true;
1099 : }
1100 : /* Copy propagation. */
1101 98252809 : else if (src_reg && cprop_reg_p (src_reg)
1102 678139 : && REGNO (src_reg) != regno
1103 98775502 : && try_replace_reg (reg_used, src_reg, insn))
1104 : {
1105 657573 : changed = true;
1106 657573 : changed_this_round = 1;
1107 657573 : global_copy_prop_count++;
1108 657573 : if (dump_file != NULL)
1109 : {
1110 4 : fprintf (dump_file,
1111 : "GLOBAL COPY-PROP: Replacing reg %d in insn %d",
1112 4 : regno, INSN_UID (insn));
1113 4 : 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 283949437 : while (changed_this_round);
1127 :
1128 283140963 : if (changed && DEBUG_INSN_P (insn))
1129 36011 : 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 349175491 : local_cprop_find_used_regs (rtx *xptr, void *data)
1141 : {
1142 349175491 : rtx x = *xptr;
1143 :
1144 349175491 : if (x == 0)
1145 : return;
1146 :
1147 349175491 : 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 1116911 : case SUBREG:
1166 1116911 : if (read_modify_subreg_p (x))
1167 : return;
1168 : break;
1169 :
1170 : default:
1171 : break;
1172 : }
1173 :
1174 344082944 : find_used_regs (xptr, data);
1175 : }
1176 :
1177 : /* Try to perform local const/copy propagation on X in INSN. */
1178 :
1179 : static bool
1180 193200038 : do_local_cprop (rtx x, rtx_insn *insn)
1181 : {
1182 193200038 : 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 193200038 : if (REG_P (x)
1187 193200038 : && (cprop_reg_p (x)
1188 63853837 : || (GET_CODE (PATTERN (insn)) != USE
1189 63110978 : && asm_noperands (PATTERN (insn)) < 0)))
1190 : {
1191 192432721 : cselib_val *val = cselib_lookup (x, GET_MODE (x), 0, VOIDmode);
1192 192432721 : struct elt_loc_list *l;
1193 :
1194 192432721 : if (!val)
1195 : return false;
1196 213373158 : for (l = val->locs; l; l = l->next)
1197 : {
1198 137890934 : rtx this_rtx = l->loc;
1199 137890934 : rtx note;
1200 :
1201 137890934 : if (cprop_constant_p (this_rtx))
1202 4119070 : newcnst = this_rtx;
1203 225321359 : 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 53699230 : && (!(note = find_reg_note (l->setting_insn, REG_EQUIV, NULL_RTX))
1210 3129 : || ! MEM_P (XEXP (note, 0))))
1211 : newreg = this_rtx;
1212 : }
1213 75482224 : if (newcnst && constprop_register (x, newcnst, insn))
1214 : {
1215 237682 : 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 237682 : local_const_prop_count++;
1225 237682 : return true;
1226 : }
1227 75244542 : else if (newreg && newreg != x && try_replace_reg (x, newreg, insn))
1228 : {
1229 1668805 : 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 1668805 : local_copy_prop_count++;
1237 1668805 : 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 1548784 : local_cprop_pass (void)
1247 : {
1248 1548784 : basic_block bb;
1249 1548784 : rtx_insn *insn;
1250 1548784 : bool changed = false;
1251 1548784 : unsigned i;
1252 :
1253 1548784 : auto_vec<rtx_insn *> uncond_traps;
1254 :
1255 1548784 : cselib_init (0);
1256 31431594 : FOR_EACH_BB_FN (bb, cfun)
1257 : {
1258 390052446 : FOR_BB_INSNS (bb, insn)
1259 : {
1260 360169636 : if (INSN_P (insn))
1261 : {
1262 313263453 : bool was_uncond_trap
1263 313263453 : = (GET_CODE (PATTERN (insn)) == TRAP_IF
1264 313263453 : && XEXP (PATTERN (insn), 0) == const1_rtx);
1265 313263453 : rtx note = find_reg_equal_equiv_note (insn);
1266 315169940 : do
1267 : {
1268 315169940 : reg_use_count = 0;
1269 315169940 : note_uses (&PATTERN (insn), local_cprop_find_used_regs,
1270 : NULL);
1271 315169940 : if (note)
1272 10075389 : local_cprop_find_used_regs (&XEXP (note, 0), NULL);
1273 :
1274 506463491 : for (i = 0; i < reg_use_count; i++)
1275 : {
1276 193200038 : if (do_local_cprop (reg_use_table[i], insn))
1277 : {
1278 1906487 : if (!DEBUG_INSN_P (insn))
1279 1864667 : changed = true;
1280 : break;
1281 : }
1282 : }
1283 315169940 : if (!was_uncond_trap
1284 315155053 : && GET_CODE (PATTERN (insn)) == TRAP_IF
1285 315169940 : && XEXP (PATTERN (insn), 0) == const1_rtx)
1286 : {
1287 0 : uncond_traps.safe_push (insn);
1288 0 : break;
1289 : }
1290 315169940 : if (insn->deleted ())
1291 : break;
1292 : }
1293 315169940 : while (i < reg_use_count);
1294 : }
1295 360169636 : cselib_process_insn (insn);
1296 : }
1297 :
1298 : /* Forget everything at the end of a basic block. */
1299 29882810 : cselib_clear_table ();
1300 : }
1301 :
1302 1548784 : cselib_finish ();
1303 :
1304 3097568 : 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 1548784 : return changed;
1313 1548784 : }
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 20961629 : fis_get_condition (rtx_insn *jump)
1327 : {
1328 20961629 : 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 13374825 : implicit_set_cond_p (const_rtx cond)
1336 : {
1337 13374825 : machine_mode mode;
1338 13374825 : rtx cst;
1339 :
1340 : /* COND must be either an EQ or NE comparison. */
1341 13374825 : 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 10788967 : if (!cprop_reg_p (XEXP (cond, 0)))
1346 : return false;
1347 :
1348 : /* The second operand of COND must be a suitable constant. */
1349 8873734 : mode = GET_MODE (XEXP (cond, 0));
1350 8873734 : 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 8873734 : 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 : return false;
1366 : }
1367 :
1368 8873728 : 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 1548784 : find_implicit_sets (void)
1385 : {
1386 1548784 : basic_block bb, dest;
1387 1548784 : rtx cond, new_rtx;
1388 1548784 : unsigned int count = 0;
1389 1548784 : bool edges_split = false;
1390 1548784 : size_t implicit_sets_size = last_basic_block_for_fn (cfun) + 10;
1391 :
1392 1548784 : implicit_sets = XCNEWVEC (rtx, implicit_sets_size);
1393 :
1394 34118751 : FOR_EACH_BB_FN (bb, cfun)
1395 : {
1396 : /* Check for more than one successor. */
1397 32569967 : if (EDGE_COUNT (bb->succs) <= 1)
1398 16534874 : continue;
1399 :
1400 16035093 : 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 16035093 : if (! cond || ! implicit_set_cond_p (cond))
1405 9484594 : continue;
1406 :
1407 6550499 : dest = GET_CODE (cond) == EQ
1408 6550499 : ? BRANCH_EDGE (bb)->dest : FALLTHRU_EDGE (bb)->dest;
1409 :
1410 : /* If DEST doesn't go anywhere, ignore it. */
1411 6550499 : 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 6550499 : if (! single_pred_p (dest))
1419 : {
1420 2688467 : dest = split_edge (find_edge (bb, dest));
1421 2688467 : edges_split = true;
1422 : }
1423 :
1424 6550499 : if (implicit_sets_size <= (size_t) dest->index)
1425 : {
1426 46187 : size_t old_implicit_sets_size = implicit_sets_size;
1427 46187 : implicit_sets_size *= 2;
1428 46187 : implicit_sets = XRESIZEVEC (rtx, implicit_sets, implicit_sets_size);
1429 46187 : memset (implicit_sets + old_implicit_sets_size, 0,
1430 46187 : (implicit_sets_size - old_implicit_sets_size) * sizeof (rtx));
1431 : }
1432 :
1433 6550499 : new_rtx = gen_rtx_SET (XEXP (cond, 0), XEXP (cond, 1));
1434 6550499 : implicit_sets[dest->index] = new_rtx;
1435 6550499 : if (dump_file)
1436 : {
1437 38 : fprintf (dump_file, "Implicit set of reg %d in ",
1438 38 : REGNO (XEXP (cond, 0)));
1439 38 : fprintf (dump_file, "basic block %d\n", dest->index);
1440 : }
1441 6550499 : count++;
1442 : }
1443 :
1444 1548784 : if (dump_file)
1445 64 : fprintf (dump_file, "Found %d implicit sets\n", count);
1446 :
1447 : /* Confess our sins. */
1448 1548784 : 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 : /* A find_bypass_set query and its result. */
1461 :
1462 : struct bypass_set_cache_entry
1463 : {
1464 : /* The register number of the query, or -1 if there was no query. */
1465 : int regno;
1466 :
1467 : /* The result of the query. */
1468 : struct cprop_expr *set;
1469 : };
1470 :
1471 : /* The last find_bypass_set query for each basic block with an index less
1472 : than bypass_last_basic_block. Jump bypassing can move an edge past a
1473 : long chain of blocks, and repeats the query for the source of the edge
1474 : at each step. */
1475 :
1476 : static struct bypass_set_cache_entry *bypass_set_cache;
1477 :
1478 : /* Find a set of REGNO to a constant that is available at the end of basic
1479 : block BB. Return NULL if no such set is found. Based heavily upon
1480 : find_avail_set. The set hash table and CPROP_AVOUT do not change
1481 : during jump bypassing, so the result is cached in bypass_set_cache. */
1482 :
1483 : static struct cprop_expr *
1484 2143481 : find_bypass_set (int regno, int bb)
1485 : {
1486 2143481 : struct cprop_expr *result = 0;
1487 :
1488 2143481 : gcc_checking_assert (bb < bypass_last_basic_block);
1489 2143481 : struct bypass_set_cache_entry *entry = &bypass_set_cache[bb];
1490 2143481 : if (entry->regno == regno)
1491 13643 : return entry->set;
1492 :
1493 : /* The loop below changes REGNO when it follows a copy. */
1494 2129838 : entry->regno = regno;
1495 :
1496 2388936 : for (;;)
1497 : {
1498 2259387 : rtx src;
1499 2259387 : struct cprop_expr *set = lookup_set (regno, &set_hash_table);
1500 :
1501 2259387 : while (set)
1502 : {
1503 2700938 : if (bitmap_bit_p (cprop_avout[bb], set->bitmap_index))
1504 : break;
1505 4608667 : set = next_set (regno, set);
1506 : }
1507 :
1508 351658 : if (set == 0)
1509 : break;
1510 :
1511 351658 : src = set->src;
1512 351658 : if (cprop_constant_p (src))
1513 222109 : result = set;
1514 :
1515 351658 : if (! REG_P (src))
1516 : break;
1517 :
1518 129549 : regno = REGNO (src);
1519 129549 : }
1520 :
1521 2129838 : entry->set = result;
1522 2129838 : return result;
1523 : }
1524 :
1525 : /* Subroutine of bypass_block that checks whether a pseudo is killed by
1526 : any of the instructions inserted on an edge. Jump bypassing places
1527 : condition code setters on CFG edges using insert_insn_on_edge. This
1528 : function is required to check that our data flow analysis is still
1529 : valid prior to commit_edge_insertions. */
1530 :
1531 : static bool
1532 768 : reg_killed_on_edge (const_rtx reg, const_edge e)
1533 : {
1534 768 : rtx_insn *insn;
1535 :
1536 1536 : for (insn = e->insns.r; insn; insn = NEXT_INSN (insn))
1537 768 : if (INSN_P (insn) && reg_set_p (reg, insn))
1538 : return true;
1539 :
1540 : return false;
1541 : }
1542 :
1543 : /* Subroutine of bypass_block. Return true if a copy of SETCC, the insn
1544 : before the jump of a bypassed block, must be placed on an edge that has
1545 : been redirected to DEST.
1546 :
1547 : The copy is not needed if SETCC has no side effects, cannot throw, and
1548 : sets only condition-code registers that are dead on entry to DEST.
1549 : Setters of other registers are always copied, because debug insns and
1550 : REG_EQUAL notes, which the liveness information ignores, can refer to
1551 : them. The liveness information predates the global propagation and
1552 : the edge redirections, but neither can make a register set by SETCC
1553 : live on entry to DEST: hard registers are never propagated, SETCC kills
1554 : every copy from a pseudo that it sets, and a redirection omits a copy
1555 : of a setter only if its registers are dead on entry to the new
1556 : destination. */
1557 :
1558 : static bool
1559 155828 : bypass_setcc_needed_p (rtx_insn *setcc, basic_block dest)
1560 : {
1561 155828 : if (side_effects_p (PATTERN (setcc)) || !insn_nothrow_p (setcc))
1562 : return true;
1563 :
1564 : /* DEST existed when the DF information was computed. */
1565 155828 : gcc_checking_assert (dest->index < bypass_last_basic_block);
1566 155828 : bitmap live = df_get_live_in (dest);
1567 155828 : df_ref def;
1568 311656 : FOR_EACH_INSN_DEF (def, setcc)
1569 156598 : if (GET_MODE_CLASS (GET_MODE (*DF_REF_REAL_LOC (def))) != MODE_CC
1570 156598 : || REGNO_REG_SET_P (live, DF_REF_REGNO (def)))
1571 : return true;
1572 :
1573 : return false;
1574 : }
1575 :
1576 : /* Subroutine of bypass_conditional_jumps that attempts to bypass the given
1577 : basic block BB which has more than one predecessor. If not NULL, SETCC
1578 : is the first instruction of BB, which is immediately followed by JUMP_INSN
1579 : JUMP. Otherwise, SETCC is NULL, and JUMP is the first insn of BB.
1580 : Returns true if a change was made.
1581 :
1582 : During the jump bypassing pass, we may place copies of SETCC instructions
1583 : on CFG edges. The following routine must be careful to pay attention to
1584 : these inserted insns when performing its transformations. */
1585 :
1586 : static bool
1587 888894 : bypass_block (basic_block bb, rtx_insn *setcc, rtx_insn *jump)
1588 : {
1589 888894 : rtx_insn *insn;
1590 888894 : rtx setcc_src, setcc_dest;
1591 888894 : rtx note;
1592 888894 : edge e, edest;
1593 888894 : bool change;
1594 888894 : bool may_be_loop_header = false;
1595 888894 : bool removed_p;
1596 888894 : unsigned i;
1597 888894 : edge_iterator ei;
1598 :
1599 888894 : if (setcc != NULL)
1600 : {
1601 888731 : rtx set = single_set (setcc);
1602 888731 : setcc_dest = SET_DEST (set);
1603 888731 : setcc_src = SET_SRC (set);
1604 888731 : insn = setcc;
1605 : }
1606 : else
1607 : {
1608 : setcc_dest = NULL;
1609 : setcc_src = NULL;
1610 : insn = jump;
1611 : }
1612 :
1613 : /* Determine set of register uses in INSN. */
1614 888894 : reg_use_count = 0;
1615 888894 : note_uses (&PATTERN (insn), find_used_regs, NULL);
1616 888894 : note = find_reg_equal_equiv_note (insn);
1617 888894 : if (note)
1618 3113 : find_used_regs (&XEXP (note, 0), NULL);
1619 :
1620 888894 : if (current_loops)
1621 : {
1622 : /* If we are to preserve loop structure then do not bypass
1623 : a loop header. This will either rotate the loop, create
1624 : multiple entry loops or even irreducible regions. */
1625 623686 : if (bb == bb->loop_father->header)
1626 : return 0;
1627 : }
1628 : else
1629 : {
1630 777711 : FOR_EACH_EDGE (e, ei, bb->preds)
1631 588296 : if (e->flags & EDGE_DFS_BACK)
1632 : {
1633 : may_be_loop_header = true;
1634 : break;
1635 : }
1636 : }
1637 :
1638 : /* The source of JUMP with SETCC substituted into it. JUMP only changes
1639 : when an edge from BB itself is redirected. With SETCC that never
1640 : happens, because DEST is a successor of BB (see the check of
1641 : find_edge (e->src, dest) below). Without SETCC, SRC is the source
1642 : of JUMP itself. */
1643 743172 : rtx src = SET_SRC (pc_set (jump));
1644 743172 : if (setcc != NULL)
1645 743104 : src = simplify_replace_rtx (src, setcc_dest, setcc_src);
1646 :
1647 743172 : change = false;
1648 2560686 : for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
1649 : {
1650 1817514 : removed_p = false;
1651 :
1652 1817514 : if (e->flags & EDGE_COMPLEX)
1653 : {
1654 4819 : ei_next (&ei);
1655 4819 : continue;
1656 : }
1657 :
1658 : /* We can't redirect edges from new basic blocks. */
1659 1812695 : if (e->src->index >= bypass_last_basic_block)
1660 : {
1661 0 : ei_next (&ei);
1662 0 : continue;
1663 : }
1664 :
1665 : /* The irreducible loops created by redirecting of edges entering the
1666 : loop from outside would decrease effectiveness of some of the
1667 : following optimizations, so prevent this. */
1668 1812695 : if (may_be_loop_header
1669 168376 : && !(e->flags & EDGE_DFS_BACK))
1670 : {
1671 80617 : ei_next (&ei);
1672 80617 : continue;
1673 : }
1674 :
1675 3719729 : for (i = 0; i < reg_use_count; i++)
1676 : {
1677 2143481 : rtx reg_used = reg_use_table[i];
1678 2143481 : unsigned int regno = REGNO (reg_used);
1679 2143481 : basic_block dest, old_dest;
1680 2143481 : struct cprop_expr *set;
1681 2143481 : rtx new_rtx;
1682 :
1683 2143481 : set = find_bypass_set (regno, e->src->index);
1684 :
1685 2143481 : if (! set)
1686 1914934 : continue;
1687 :
1688 : /* Check the data flow is valid after edge insertions. */
1689 228547 : if (e->insns.r && reg_killed_on_edge (reg_used, e))
1690 0 : continue;
1691 :
1692 228547 : new_rtx = simplify_replace_rtx (src, reg_used, set->src);
1693 :
1694 : /* Jump bypassing may have already placed instructions on
1695 : edges of the CFG. We can't bypass an outgoing edge that
1696 : has instructions associated with it, as these insns won't
1697 : get executed if the incoming edge is redirected. */
1698 228547 : if (new_rtx == pc_rtx)
1699 : {
1700 79168 : edest = FALLTHRU_EDGE (bb);
1701 79168 : dest = edest->insns.r ? NULL : edest->dest;
1702 : }
1703 149379 : else if (GET_CODE (new_rtx) == LABEL_REF)
1704 : {
1705 76668 : dest = BLOCK_FOR_INSN (label_ref_label (new_rtx));
1706 : /* Don't bypass edges containing instructions. */
1707 76668 : if (dest)
1708 : {
1709 76664 : edest = find_edge (bb, dest);
1710 76664 : if (edest && edest->insns.r)
1711 228547 : dest = NULL;
1712 : }
1713 : }
1714 : else
1715 : dest = NULL;
1716 :
1717 : /* Avoid unification of the edge with other edges from original
1718 : branch. We would end up emitting the instruction on "both"
1719 : edges. */
1720 228547 : if (dest && setcc && find_edge (e->src, dest))
1721 : dest = NULL;
1722 :
1723 228547 : old_dest = e->dest;
1724 228547 : if (dest != NULL
1725 228547 : && dest != old_dest
1726 155830 : && dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
1727 : {
1728 155830 : redirect_edge_and_branch_force (e, dest);
1729 :
1730 : /* Copy the register setter to the redirected edge if it is
1731 : needed on entry to DEST. */
1732 155830 : if (setcc && bypass_setcc_needed_p (setcc, dest))
1733 : {
1734 770 : rtx pat = PATTERN (setcc);
1735 770 : insert_insn_on_edge (copy_insn (pat), e);
1736 : }
1737 :
1738 155830 : if (dump_file != NULL)
1739 : {
1740 28 : fprintf (dump_file, "JUMP-BYPASS: Proved reg %d "
1741 : "in jump_insn %d equals constant ",
1742 28 : regno, INSN_UID (jump));
1743 28 : print_rtl (dump_file, set->src);
1744 28 : fprintf (dump_file, "\n\t when BB %d is entered from "
1745 : "BB %d. Redirect edge %d->%d to %d.\n",
1746 28 : old_dest->index, e->src->index, e->src->index,
1747 : old_dest->index, dest->index);
1748 : }
1749 : change = true;
1750 : removed_p = true;
1751 : break;
1752 : }
1753 : }
1754 1732078 : if (!removed_p)
1755 1576248 : ei_next (&ei);
1756 : }
1757 : return change;
1758 : }
1759 :
1760 : /* Find basic blocks with more than one predecessor that only contain a
1761 : single conditional jump. If the result of the comparison is known at
1762 : compile-time from any incoming edge, redirect that edge to the
1763 : appropriate target. Return nonzero if a change was made.
1764 :
1765 : This function is now mis-named, because we also handle indirect jumps. */
1766 :
1767 : static bool
1768 1396900 : bypass_conditional_jumps (void)
1769 : {
1770 1396900 : basic_block bb;
1771 1396900 : bool changed;
1772 1396900 : rtx_insn *setcc;
1773 1396900 : rtx_insn *insn;
1774 1396900 : rtx dest;
1775 :
1776 : /* Note we start at block 1. */
1777 1396900 : if (ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
1778 : return false;
1779 :
1780 1396900 : mark_dfs_back_edges ();
1781 :
1782 1396900 : bypass_set_cache = XNEWVEC (struct bypass_set_cache_entry,
1783 : bypass_last_basic_block);
1784 37569357 : for (int i = 0; i < bypass_last_basic_block; i++)
1785 36172457 : bypass_set_cache[i].regno = -1;
1786 :
1787 1396900 : changed = false;
1788 31883969 : FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->next_bb,
1789 : EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb)
1790 : {
1791 : /* Check for more than one predecessor. */
1792 30487069 : if (!single_pred_p (bb))
1793 : {
1794 8170566 : setcc = NULL;
1795 65846539 : FOR_BB_INSNS (bb, insn)
1796 64907227 : if (DEBUG_INSN_P (insn))
1797 35065905 : continue;
1798 29841322 : else if (NONJUMP_INSN_P (insn))
1799 : {
1800 12152663 : if (setcc)
1801 : break;
1802 7644517 : rtx singleset = single_set (insn);
1803 7644517 : if (singleset == NULL_RTX)
1804 : break;
1805 :
1806 7547828 : dest = SET_DEST (singleset);
1807 7547828 : if (REG_P (dest))
1808 : setcc = insn;
1809 : else
1810 : break;
1811 : }
1812 17688659 : else if (JUMP_P (insn))
1813 : {
1814 889409 : if ((any_condjump_p (insn) || computed_jump_p (insn))
1815 889237 : && onlyjump_p (insn))
1816 888894 : if (bypass_block (bb, setcc, insn))
1817 30487069 : changed = true;
1818 : break;
1819 : }
1820 16799587 : else if (INSN_P (insn))
1821 : break;
1822 : }
1823 : }
1824 :
1825 1396900 : free (bypass_set_cache);
1826 1396900 : bypass_set_cache = NULL;
1827 :
1828 : /* If we bypassed any register setting insns, we may have inserted
1829 : copies of them on the redirected edges. These need to be committed. */
1830 1396900 : if (changed)
1831 43961 : commit_edge_insertions ();
1832 :
1833 : return changed;
1834 : }
1835 :
1836 : /* Main function for the CPROP pass. */
1837 :
1838 : static bool
1839 2963244 : one_cprop_pass (void)
1840 : {
1841 2963244 : bool changed = false;
1842 2963244 : int i;
1843 :
1844 : /* Return if there's nothing to do, or it is too expensive. */
1845 2963244 : if (n_basic_blocks_for_fn (cfun) <= NUM_FIXED_BLOCKS + 1
1846 2963244 : || gcse_or_cprop_is_too_expensive (_ ("const/copy propagation disabled")))
1847 : return false;
1848 :
1849 1548784 : global_const_prop_count = local_const_prop_count = 0;
1850 1548784 : global_copy_prop_count = local_copy_prop_count = 0;
1851 :
1852 1548784 : bytes_used = 0;
1853 1548784 : gcc_obstack_init (&cprop_obstack);
1854 :
1855 : /* Do a local const/copy propagation pass first. The global pass
1856 : only handles global opportunities.
1857 : If the local pass changes something, remove any unreachable blocks
1858 : because the CPROP global dataflow analysis may get into infinite
1859 : loops for CFGs with unreachable blocks.
1860 :
1861 : FIXME: This local pass should not be necessary after CSE (but for
1862 : some reason it still is). It is also (proven) not necessary
1863 : to run the local pass right after FWPWOP.
1864 :
1865 : FIXME: The global analysis would not get into infinite loops if it
1866 : would use the DF solver (via df_simple_dataflow) instead of
1867 : the solver implemented in this file. */
1868 1548784 : if (local_cprop_pass ())
1869 227757 : changed = true;
1870 :
1871 227757 : if (changed)
1872 227757 : delete_unreachable_blocks ();
1873 :
1874 : /* Determine implicit sets. This may change the CFG (split critical
1875 : edges if that exposes an implicit set).
1876 : Note that find_implicit_sets() does not rely on up-to-date DF caches
1877 : so that we do not have to re-run df_analyze() even if local CPROP
1878 : changed something.
1879 : ??? This could run earlier so that any uncovered implicit sets
1880 : sets could be exploited in local_cprop_pass() also. Later. */
1881 1548784 : if (find_implicit_sets ())
1882 : changed = true;
1883 :
1884 : /* If local_cprop_pass() or find_implicit_sets() changed something,
1885 : run df_analyze() to bring all insn caches up-to-date, and to take
1886 : new basic blocks from edge splitting on the DF radar.
1887 : NB: This also runs the fast DCE pass, because execute_rtl_cprop
1888 : sets DF_LR_RUN_DCE. */
1889 934847 : if (changed)
1890 707424 : df_analyze ();
1891 :
1892 : /* Initialize implicit_set_indexes array. */
1893 1548784 : implicit_set_indexes = XNEWVEC (int, last_basic_block_for_fn (cfun));
1894 38750987 : for (i = 0; i < last_basic_block_for_fn (cfun); i++)
1895 37202203 : implicit_set_indexes[i] = -1;
1896 :
1897 1548784 : alloc_hash_table (&set_hash_table);
1898 1548784 : compute_hash_table (&set_hash_table);
1899 :
1900 : /* Free implicit_sets before peak usage. */
1901 1548784 : free (implicit_sets);
1902 1548784 : implicit_sets = NULL;
1903 :
1904 1548784 : if (dump_file)
1905 64 : dump_hash_table (dump_file, "SET", &set_hash_table);
1906 1548784 : if (set_hash_table.n_elems > 0)
1907 : {
1908 1396900 : basic_block bb;
1909 1396900 : auto_vec<rtx_insn *> uncond_traps;
1910 :
1911 1396900 : alloc_cprop_mem (last_basic_block_for_fn (cfun),
1912 : set_hash_table.n_elems);
1913 1396900 : compute_cprop_data ();
1914 :
1915 1396900 : free (implicit_set_indexes);
1916 1396900 : implicit_set_indexes = NULL;
1917 :
1918 : /* Allocate vars to track sets of regs. */
1919 1396900 : reg_set_bitmap = ALLOC_REG_SET (NULL);
1920 :
1921 31883969 : FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->next_bb,
1922 : EXIT_BLOCK_PTR_FOR_FN (cfun),
1923 : next_bb)
1924 : {
1925 30487069 : bool seen_uncond_trap = false;
1926 30487069 : rtx_insn *insn;
1927 :
1928 : /* Reset tables used to keep track of what's still valid [since
1929 : the start of the block]. */
1930 30487069 : reset_opr_set_tables ();
1931 :
1932 361215914 : FOR_BB_INSNS (bb, insn)
1933 330728845 : if (INSN_P (insn))
1934 : {
1935 283140963 : bool was_uncond_trap
1936 283140963 : = (GET_CODE (PATTERN (insn)) == TRAP_IF
1937 283140963 : && XEXP (PATTERN (insn), 0) == const1_rtx);
1938 :
1939 283140963 : if (cprop_insn (insn))
1940 772425 : changed = true;
1941 :
1942 : /* Keep track of everything modified by this insn. */
1943 : /* ??? Need to be careful w.r.t. mods done to INSN.
1944 : Don't call mark_oprs_set if we turned the
1945 : insn into a NOTE, or deleted the insn. */
1946 283140963 : if (! NOTE_P (insn) && ! insn->deleted ())
1947 283140963 : mark_oprs_set (insn);
1948 :
1949 283140963 : if (!was_uncond_trap
1950 283127216 : && GET_CODE (PATTERN (insn)) == TRAP_IF
1951 283140963 : && XEXP (PATTERN (insn), 0) == const1_rtx)
1952 : {
1953 : /* If we have already seen an unconditional trap
1954 : earlier, the rest of the bb is going to be removed
1955 : as unreachable. Just turn it into a note, so that
1956 : RTL verification doesn't complain about it before
1957 : it is finally removed. */
1958 0 : if (seen_uncond_trap)
1959 0 : set_insn_deleted (insn);
1960 : else
1961 : {
1962 0 : seen_uncond_trap = true;
1963 0 : uncond_traps.safe_push (insn);
1964 : }
1965 : }
1966 : }
1967 : }
1968 :
1969 : /* Make sure bypass_conditional_jumps will ignore not just its new
1970 : basic blocks, but also the ones after unconditional traps (those are
1971 : unreachable and will be eventually removed as such). */
1972 1396900 : bypass_last_basic_block = last_basic_block_for_fn (cfun);
1973 :
1974 1396900 : while (!uncond_traps.is_empty ())
1975 : {
1976 0 : rtx_insn *insn = uncond_traps.pop ();
1977 0 : basic_block to_split = BLOCK_FOR_INSN (insn);
1978 0 : remove_edge (split_block (to_split, insn));
1979 0 : emit_barrier_after_bb (to_split);
1980 : }
1981 :
1982 1396900 : if (bypass_conditional_jumps ())
1983 43961 : changed = true;
1984 :
1985 1396900 : FREE_REG_SET (reg_set_bitmap);
1986 1396900 : free_cprop_mem ();
1987 1396900 : }
1988 : else
1989 : {
1990 151884 : free (implicit_set_indexes);
1991 151884 : implicit_set_indexes = NULL;
1992 : }
1993 :
1994 1548784 : free_hash_table (&set_hash_table);
1995 1548784 : obstack_free (&cprop_obstack, NULL);
1996 :
1997 1548784 : if (dump_file)
1998 : {
1999 64 : fprintf (dump_file, "CPROP of %s, %d basic blocks, %d bytes needed, ",
2000 64 : current_function_name (), n_basic_blocks_for_fn (cfun),
2001 : bytes_used);
2002 64 : fprintf (dump_file, "%d local const props, %d local copy props, ",
2003 : local_const_prop_count, local_copy_prop_count);
2004 64 : fprintf (dump_file, "%d global const props, %d global copy props\n\n",
2005 : global_const_prop_count, global_copy_prop_count);
2006 : }
2007 :
2008 : return changed;
2009 : }
2010 :
2011 : /* All the passes implemented in this file. Each pass has its
2012 : own gate and execute function, and at the end of the file a
2013 : pass definition for passes.cc.
2014 :
2015 : We do not construct an accurate cfg in functions which call
2016 : setjmp, so none of these passes runs if the function calls
2017 : setjmp.
2018 : FIXME: Should just handle setjmp via REG_SETJMP notes. */
2019 :
2020 : static unsigned int
2021 2963244 : execute_rtl_cprop (void)
2022 : {
2023 2963244 : int changed;
2024 2963244 : delete_unreachable_blocks ();
2025 2963244 : df_set_flags (DF_LR_RUN_DCE);
2026 2963244 : df_analyze ();
2027 2963244 : changed = one_cprop_pass ();
2028 2963244 : flag_rerun_cse_after_global_opts |= changed;
2029 2963244 : if (changed)
2030 746495 : cleanup_cfg (CLEANUP_CFG_CHANGED);
2031 2963244 : return 0;
2032 : }
2033 :
2034 : namespace {
2035 :
2036 : const pass_data pass_data_rtl_cprop =
2037 : {
2038 : RTL_PASS, /* type */
2039 : "cprop", /* name */
2040 : OPTGROUP_NONE, /* optinfo_flags */
2041 : TV_CPROP, /* tv_id */
2042 : PROP_cfglayout, /* properties_required */
2043 : 0, /* properties_provided */
2044 : 0, /* properties_destroyed */
2045 : 0, /* todo_flags_start */
2046 : TODO_df_finish, /* todo_flags_finish */
2047 : };
2048 :
2049 : class pass_rtl_cprop : public rtl_opt_pass
2050 : {
2051 : public:
2052 883608 : pass_rtl_cprop (gcc::context *ctxt)
2053 1767216 : : rtl_opt_pass (pass_data_rtl_cprop, ctxt)
2054 : {}
2055 :
2056 : /* opt_pass methods: */
2057 589072 : opt_pass * clone () final override { return new pass_rtl_cprop (m_ctxt); }
2058 4547787 : bool gate (function *fun) final override
2059 : {
2060 3210579 : return optimize > 0 && flag_gcse
2061 2965401 : && !fun->calls_setjmp
2062 7511034 : && dbg_cnt (cprop);
2063 : }
2064 :
2065 2963244 : unsigned int execute (function *) final override
2066 : {
2067 2963244 : return execute_rtl_cprop ();
2068 : }
2069 :
2070 : }; // class pass_rtl_cprop
2071 :
2072 : } // anon namespace
2073 :
2074 : rtl_opt_pass *
2075 294536 : make_pass_rtl_cprop (gcc::context *ctxt)
2076 : {
2077 294536 : return new pass_rtl_cprop (ctxt);
2078 : }
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