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0516f6fe | 1 | /* Post reload partially redundant load elimination |
8d9254fc | 2 | Copyright (C) 2004-2020 Free Software Foundation, Inc. |
0516f6fe SB |
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 | |
9dcd6f09 | 8 | Software Foundation; either version 3, or (at your option) any later |
0516f6fe SB |
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 | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
0516f6fe SB |
19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "coretypes.h" | |
c7131fb2 | 23 | #include "backend.h" |
957060b5 | 24 | #include "target.h" |
c7131fb2 | 25 | #include "rtl.h" |
957060b5 AM |
26 | #include "tree.h" |
27 | #include "predict.h" | |
c7131fb2 | 28 | #include "df.h" |
4d0cdd0c | 29 | #include "memmodel.h" |
957060b5 | 30 | #include "tm_p.h" |
957060b5 | 31 | #include "insn-config.h" |
957060b5 AM |
32 | #include "emit-rtl.h" |
33 | #include "recog.h" | |
0516f6fe | 34 | |
60393bbc | 35 | #include "cfgrtl.h" |
59f2e9d8 | 36 | #include "profile.h" |
0516f6fe | 37 | #include "expr.h" |
ef330312 | 38 | #include "tree-pass.h" |
6fb5fa3c | 39 | #include "dbgcnt.h" |
dc91c653 | 40 | #include "intl.h" |
af3eb110 | 41 | #include "gcse-common.h" |
dc91c653 | 42 | #include "gcse.h" |
7187286e RS |
43 | #include "regs.h" |
44 | #include "function-abi.h" | |
0516f6fe SB |
45 | |
46 | /* The following code implements gcse after reload, the purpose of this | |
47 | pass is to cleanup redundant loads generated by reload and other | |
48 | optimizations that come after gcse. It searches for simple inter-block | |
49 | redundancies and tries to eliminate them by adding moves and loads | |
50 | in cold places. | |
51 | ||
52 | Perform partially redundant load elimination, try to eliminate redundant | |
53 | loads created by the reload pass. We try to look for full or partial | |
54 | redundant loads fed by one or more loads/stores in predecessor BBs, | |
55 | and try adding loads to make them fully redundant. We also check if | |
56 | it's worth adding loads to be able to delete the redundant load. | |
57 | ||
58 | Algorithm: | |
59 | 1. Build available expressions hash table: | |
60 | For each load/store instruction, if the loaded/stored memory didn't | |
61 | change until the end of the basic block add this memory expression to | |
62 | the hash table. | |
63 | 2. Perform Redundancy elimination: | |
64 | For each load instruction do the following: | |
65 | perform partial redundancy elimination, check if it's worth adding | |
66 | loads to make the load fully redundant. If so add loads and | |
67 | register copies and delete the load. | |
68 | 3. Delete instructions made redundant in step 2. | |
69 | ||
70 | Future enhancement: | |
71 | If the loaded register is used/defined between load and some store, | |
72 | look for some other free register between load and all its stores, | |
73 | and replace the load with a copy from this register to the loaded | |
74 | register. | |
75 | */ | |
76 | \f | |
77 | ||
78 | /* Keep statistics of this pass. */ | |
79 | static struct | |
80 | { | |
81 | int moves_inserted; | |
82 | int copies_inserted; | |
83 | int insns_deleted; | |
84 | } stats; | |
85 | ||
86 | /* We need to keep a hash table of expressions. The table entries are of | |
87 | type 'struct expr', and for each expression there is a single linked | |
2a7e31df | 88 | list of occurrences. */ |
0516f6fe | 89 | |
0516f6fe SB |
90 | /* Expression elements in the hash table. */ |
91 | struct expr | |
92 | { | |
93 | /* The expression (SET_SRC for expressions, PATTERN for assignments). */ | |
94 | rtx expr; | |
95 | ||
96 | /* The same hash for this entry. */ | |
97 | hashval_t hash; | |
98 | ||
af3eb110 JL |
99 | /* Index in the transparent bitmaps. */ |
100 | unsigned int bitmap_index; | |
101 | ||
0516f6fe SB |
102 | /* List of available occurrence in basic blocks in the function. */ |
103 | struct occr *avail_occr; | |
104 | }; | |
105 | ||
4a8fb1a1 LC |
106 | /* Hashtable helpers. */ |
107 | ||
8d67ee55 | 108 | struct expr_hasher : nofree_ptr_hash <expr> |
4a8fb1a1 | 109 | { |
67f58944 TS |
110 | static inline hashval_t hash (const expr *); |
111 | static inline bool equal (const expr *, const expr *); | |
4a8fb1a1 LC |
112 | }; |
113 | ||
114 | ||
115 | /* Hash expression X. | |
116 | DO_NOT_RECORD_P is a boolean indicating if a volatile operand is found | |
117 | or if the expression contains something we don't want to insert in the | |
118 | table. */ | |
119 | ||
120 | static hashval_t | |
121 | hash_expr (rtx x, int *do_not_record_p) | |
122 | { | |
123 | *do_not_record_p = 0; | |
124 | return hash_rtx (x, GET_MODE (x), do_not_record_p, | |
125 | NULL, /*have_reg_qty=*/false); | |
126 | } | |
127 | ||
128 | /* Callback for hashtab. | |
129 | Return the hash value for expression EXP. We don't actually hash | |
130 | here, we just return the cached hash value. */ | |
131 | ||
132 | inline hashval_t | |
67f58944 | 133 | expr_hasher::hash (const expr *exp) |
4a8fb1a1 LC |
134 | { |
135 | return exp->hash; | |
136 | } | |
137 | ||
138 | /* Callback for hashtab. | |
139 | Return nonzero if exp1 is equivalent to exp2. */ | |
140 | ||
141 | inline bool | |
67f58944 | 142 | expr_hasher::equal (const expr *exp1, const expr *exp2) |
4a8fb1a1 LC |
143 | { |
144 | int equiv_p = exp_equiv_p (exp1->expr, exp2->expr, 0, true); | |
145 | ||
146 | gcc_assert (!equiv_p || exp1->hash == exp2->hash); | |
147 | return equiv_p; | |
148 | } | |
149 | ||
150 | /* The table itself. */ | |
c203e8a7 | 151 | static hash_table<expr_hasher> *expr_table; |
4a8fb1a1 LC |
152 | \f |
153 | ||
0516f6fe SB |
154 | static struct obstack expr_obstack; |
155 | ||
156 | /* Occurrence of an expression. | |
2a7e31df | 157 | There is at most one occurrence per basic block. If a pattern appears |
0516f6fe SB |
158 | more than once, the last appearance is used. */ |
159 | ||
160 | struct occr | |
161 | { | |
162 | /* Next occurrence of this expression. */ | |
163 | struct occr *next; | |
164 | /* The insn that computes the expression. */ | |
6c6d76be | 165 | rtx_insn *insn; |
0516f6fe SB |
166 | /* Nonzero if this [anticipatable] occurrence has been deleted. */ |
167 | char deleted_p; | |
168 | }; | |
169 | ||
170 | static struct obstack occr_obstack; | |
171 | ||
172 | /* The following structure holds the information about the occurrences of | |
173 | the redundant instructions. */ | |
174 | struct unoccr | |
175 | { | |
176 | struct unoccr *next; | |
177 | edge pred; | |
6c6d76be | 178 | rtx_insn *insn; |
0516f6fe SB |
179 | }; |
180 | ||
181 | static struct obstack unoccr_obstack; | |
182 | ||
183 | /* Array where each element is the CUID if the insn that last set the hard | |
184 | register with the number of the element, since the start of the current | |
c93320c4 SB |
185 | basic block. |
186 | ||
187 | This array is used during the building of the hash table (step 1) to | |
188 | determine if a reg is killed before the end of a basic block. | |
189 | ||
190 | It is also used when eliminating partial redundancies (step 2) to see | |
191 | if a reg was modified since the start of a basic block. */ | |
0516f6fe SB |
192 | static int *reg_avail_info; |
193 | ||
194 | /* A list of insns that may modify memory within the current basic block. */ | |
195 | struct modifies_mem | |
196 | { | |
6c6d76be | 197 | rtx_insn *insn; |
0516f6fe SB |
198 | struct modifies_mem *next; |
199 | }; | |
200 | static struct modifies_mem *modifies_mem_list; | |
201 | ||
202 | /* The modifies_mem structs also go on an obstack, only this obstack is | |
203 | freed each time after completing the analysis or transformations on | |
204 | a basic block. So we allocate a dummy modifies_mem_obstack_bottom | |
205 | object on the obstack to keep track of the bottom of the obstack. */ | |
206 | static struct obstack modifies_mem_obstack; | |
207 | static struct modifies_mem *modifies_mem_obstack_bottom; | |
208 | ||
209 | /* Mapping of insn UIDs to CUIDs. | |
210 | CUIDs are like UIDs except they increase monotonically in each basic | |
211 | block, have no gaps, and only apply to real insns. */ | |
212 | static int *uid_cuid; | |
213 | #define INSN_CUID(INSN) (uid_cuid[INSN_UID (INSN)]) | |
af3eb110 JL |
214 | |
215 | /* Bitmap of blocks which have memory stores. */ | |
216 | static bitmap modify_mem_list_set; | |
217 | ||
218 | /* Bitmap of blocks which have calls. */ | |
219 | static bitmap blocks_with_calls; | |
220 | ||
221 | /* Vector indexed by block # with a list of all the insns that | |
222 | modify memory within the block. */ | |
223 | static vec<rtx_insn *> *modify_mem_list; | |
224 | ||
225 | /* Vector indexed by block # with a canonicalized list of insns | |
226 | that modify memory in the block. */ | |
227 | static vec<modify_pair> *canon_modify_mem_list; | |
228 | ||
229 | /* Vector of simple bitmaps indexed by block number. Each component sbitmap | |
230 | indicates which expressions are transparent through the block. */ | |
231 | static sbitmap *transp; | |
0516f6fe SB |
232 | \f |
233 | ||
234 | /* Helpers for memory allocation/freeing. */ | |
235 | static void alloc_mem (void); | |
236 | static void free_mem (void); | |
237 | ||
238 | /* Support for hash table construction and transformations. */ | |
6c6d76be DM |
239 | static bool oprs_unchanged_p (rtx, rtx_insn *, bool); |
240 | static void record_last_reg_set_info (rtx_insn *, rtx); | |
241 | static void record_last_reg_set_info_regno (rtx_insn *, int); | |
242 | static void record_last_mem_set_info (rtx_insn *); | |
7bc980e1 | 243 | static void record_last_set_info (rtx, const_rtx, void *); |
6c6d76be | 244 | static void record_opr_changes (rtx_insn *); |
0516f6fe | 245 | |
7bc980e1 | 246 | static void find_mem_conflicts (rtx, const_rtx, void *); |
0516f6fe SB |
247 | static int load_killed_in_block_p (int, rtx, bool); |
248 | static void reset_opr_set_tables (void); | |
249 | ||
250 | /* Hash table support. */ | |
251 | static hashval_t hash_expr (rtx, int *); | |
6c6d76be | 252 | static void insert_expr_in_table (rtx, rtx_insn *); |
0516f6fe | 253 | static struct expr *lookup_expr_in_table (rtx); |
0516f6fe SB |
254 | static void dump_hash_table (FILE *); |
255 | ||
256 | /* Helpers for eliminate_partially_redundant_load. */ | |
257 | static bool reg_killed_on_edge (rtx, edge); | |
258 | static bool reg_used_on_edge (rtx, edge); | |
259 | ||
6c6d76be | 260 | static rtx get_avail_load_store_reg (rtx_insn *); |
0516f6fe SB |
261 | |
262 | static bool bb_has_well_behaved_predecessors (basic_block); | |
af3eb110 | 263 | static struct occr* get_bb_avail_insn (basic_block, struct occr *, int); |
6c6d76be | 264 | static void hash_scan_set (rtx_insn *); |
0516f6fe SB |
265 | static void compute_hash_table (void); |
266 | ||
267 | /* The work horses of this pass. */ | |
268 | static void eliminate_partially_redundant_load (basic_block, | |
6c6d76be | 269 | rtx_insn *, |
0516f6fe SB |
270 | struct expr *); |
271 | static void eliminate_partially_redundant_loads (void); | |
272 | \f | |
273 | ||
274 | /* Allocate memory for the CUID mapping array and register/memory | |
275 | tracking tables. */ | |
276 | ||
277 | static void | |
278 | alloc_mem (void) | |
279 | { | |
280 | int i; | |
281 | basic_block bb; | |
6c6d76be | 282 | rtx_insn *insn; |
0516f6fe SB |
283 | |
284 | /* Find the largest UID and create a mapping from UIDs to CUIDs. */ | |
5ed6ace5 | 285 | uid_cuid = XCNEWVEC (int, get_max_uid () + 1); |
576a4795 | 286 | i = 1; |
11cd3bed | 287 | FOR_EACH_BB_FN (bb, cfun) |
0516f6fe SB |
288 | FOR_BB_INSNS (bb, insn) |
289 | { | |
290 | if (INSN_P (insn)) | |
291 | uid_cuid[INSN_UID (insn)] = i++; | |
292 | else | |
293 | uid_cuid[INSN_UID (insn)] = i; | |
294 | } | |
295 | ||
296 | /* Allocate the available expressions hash table. We don't want to | |
297 | make the hash table too small, but unnecessarily making it too large | |
298 | also doesn't help. The i/4 is a gcse.c relic, and seems like a | |
299 | reasonable choice. */ | |
c203e8a7 | 300 | expr_table = new hash_table<expr_hasher> (MAX (i / 4, 13)); |
0516f6fe SB |
301 | |
302 | /* We allocate everything on obstacks because we often can roll back | |
303 | the whole obstack to some point. Freeing obstacks is very fast. */ | |
304 | gcc_obstack_init (&expr_obstack); | |
305 | gcc_obstack_init (&occr_obstack); | |
306 | gcc_obstack_init (&unoccr_obstack); | |
307 | gcc_obstack_init (&modifies_mem_obstack); | |
308 | ||
309 | /* Working array used to track the last set for each register | |
310 | in the current block. */ | |
311 | reg_avail_info = (int *) xmalloc (FIRST_PSEUDO_REGISTER * sizeof (int)); | |
312 | ||
313 | /* Put a dummy modifies_mem object on the modifies_mem_obstack, so we | |
314 | can roll it back in reset_opr_set_tables. */ | |
315 | modifies_mem_obstack_bottom = | |
316 | (struct modifies_mem *) obstack_alloc (&modifies_mem_obstack, | |
317 | sizeof (struct modifies_mem)); | |
af3eb110 JL |
318 | |
319 | blocks_with_calls = BITMAP_ALLOC (NULL); | |
320 | modify_mem_list_set = BITMAP_ALLOC (NULL); | |
321 | ||
322 | modify_mem_list = (vec_rtx_heap *) xcalloc (last_basic_block_for_fn (cfun), | |
323 | sizeof (vec_rtx_heap)); | |
324 | canon_modify_mem_list | |
325 | = (vec_modify_pair_heap *) xcalloc (last_basic_block_for_fn (cfun), | |
326 | sizeof (vec_modify_pair_heap)); | |
0516f6fe SB |
327 | } |
328 | ||
329 | /* Free memory allocated by alloc_mem. */ | |
330 | ||
331 | static void | |
332 | free_mem (void) | |
333 | { | |
334 | free (uid_cuid); | |
335 | ||
c203e8a7 TS |
336 | delete expr_table; |
337 | expr_table = NULL; | |
0516f6fe SB |
338 | |
339 | obstack_free (&expr_obstack, NULL); | |
340 | obstack_free (&occr_obstack, NULL); | |
341 | obstack_free (&unoccr_obstack, NULL); | |
342 | obstack_free (&modifies_mem_obstack, NULL); | |
343 | ||
af3eb110 JL |
344 | unsigned i; |
345 | bitmap_iterator bi; | |
346 | EXECUTE_IF_SET_IN_BITMAP (modify_mem_list_set, 0, i, bi) | |
347 | { | |
348 | modify_mem_list[i].release (); | |
349 | canon_modify_mem_list[i].release (); | |
350 | } | |
351 | ||
352 | BITMAP_FREE (blocks_with_calls); | |
353 | BITMAP_FREE (modify_mem_list_set); | |
0516f6fe | 354 | free (reg_avail_info); |
ff569744 RB |
355 | free (modify_mem_list); |
356 | free (canon_modify_mem_list); | |
0516f6fe SB |
357 | } |
358 | \f | |
359 | ||
0516f6fe SB |
360 | /* Insert expression X in INSN in the hash TABLE. |
361 | If it is already present, record it as the last occurrence in INSN's | |
362 | basic block. */ | |
363 | ||
364 | static void | |
6c6d76be | 365 | insert_expr_in_table (rtx x, rtx_insn *insn) |
0516f6fe SB |
366 | { |
367 | int do_not_record_p; | |
368 | hashval_t hash; | |
369 | struct expr *cur_expr, **slot; | |
dc91c653 | 370 | struct occr *avail_occr; |
0516f6fe SB |
371 | |
372 | hash = hash_expr (x, &do_not_record_p); | |
373 | ||
374 | /* Do not insert expression in the table if it contains volatile operands, | |
375 | or if hash_expr determines the expression is something we don't want | |
376 | to or can't handle. */ | |
377 | if (do_not_record_p) | |
378 | return; | |
379 | ||
380 | /* We anticipate that redundant expressions are rare, so for convenience | |
381 | allocate a new hash table element here already and set its fields. | |
382 | If we don't do this, we need a hack with a static struct expr. Anyway, | |
383 | obstack_free is really fast and one more obstack_alloc doesn't hurt if | |
384 | we're going to see more expressions later on. */ | |
385 | cur_expr = (struct expr *) obstack_alloc (&expr_obstack, | |
386 | sizeof (struct expr)); | |
387 | cur_expr->expr = x; | |
388 | cur_expr->hash = hash; | |
389 | cur_expr->avail_occr = NULL; | |
390 | ||
c203e8a7 | 391 | slot = expr_table->find_slot_with_hash (cur_expr, hash, INSERT); |
b8698a0f | 392 | |
0516f6fe | 393 | if (! (*slot)) |
af3eb110 JL |
394 | { |
395 | /* The expression isn't found, so insert it. */ | |
396 | *slot = cur_expr; | |
397 | ||
398 | /* Anytime we add an entry to the table, record the index | |
399 | of the new entry. The bitmap index starts counting | |
400 | at zero. */ | |
401 | cur_expr->bitmap_index = expr_table->elements () - 1; | |
402 | } | |
0516f6fe SB |
403 | else |
404 | { | |
405 | /* The expression is already in the table, so roll back the | |
406 | obstack and use the existing table entry. */ | |
407 | obstack_free (&expr_obstack, cur_expr); | |
408 | cur_expr = *slot; | |
409 | } | |
410 | ||
dc91c653 RB |
411 | /* Search for another occurrence in the same basic block. We insert |
412 | insns blockwise from start to end, so keep appending to the | |
413 | start of the list so we have to check only a single element. */ | |
0516f6fe | 414 | avail_occr = cur_expr->avail_occr; |
dc91c653 RB |
415 | if (avail_occr |
416 | && BLOCK_FOR_INSN (avail_occr->insn) == BLOCK_FOR_INSN (insn)) | |
0516f6fe SB |
417 | avail_occr->insn = insn; |
418 | else | |
419 | { | |
420 | /* First occurrence of this expression in this basic block. */ | |
421 | avail_occr = (struct occr *) obstack_alloc (&occr_obstack, | |
422 | sizeof (struct occr)); | |
0516f6fe | 423 | avail_occr->insn = insn; |
dc91c653 | 424 | avail_occr->next = cur_expr->avail_occr; |
0516f6fe | 425 | avail_occr->deleted_p = 0; |
dc91c653 | 426 | cur_expr->avail_occr = avail_occr; |
0516f6fe SB |
427 | } |
428 | } | |
429 | \f | |
430 | ||
431 | /* Lookup pattern PAT in the expression hash table. | |
432 | The result is a pointer to the table entry, or NULL if not found. */ | |
433 | ||
434 | static struct expr * | |
435 | lookup_expr_in_table (rtx pat) | |
436 | { | |
437 | int do_not_record_p; | |
438 | struct expr **slot, *tmp_expr; | |
439 | hashval_t hash = hash_expr (pat, &do_not_record_p); | |
440 | ||
441 | if (do_not_record_p) | |
442 | return NULL; | |
443 | ||
444 | tmp_expr = (struct expr *) obstack_alloc (&expr_obstack, | |
445 | sizeof (struct expr)); | |
446 | tmp_expr->expr = pat; | |
447 | tmp_expr->hash = hash; | |
448 | tmp_expr->avail_occr = NULL; | |
449 | ||
c203e8a7 | 450 | slot = expr_table->find_slot_with_hash (tmp_expr, hash, INSERT); |
0516f6fe SB |
451 | obstack_free (&expr_obstack, tmp_expr); |
452 | ||
453 | if (!slot) | |
454 | return NULL; | |
455 | else | |
456 | return (*slot); | |
457 | } | |
458 | \f | |
459 | ||
2a7e31df | 460 | /* Dump all expressions and occurrences that are currently in the |
0516f6fe SB |
461 | expression hash table to FILE. */ |
462 | ||
463 | /* This helper is called via htab_traverse. */ | |
4a8fb1a1 LC |
464 | int |
465 | dump_expr_hash_table_entry (expr **slot, FILE *file) | |
0516f6fe | 466 | { |
4a8fb1a1 | 467 | struct expr *exprs = *slot; |
0516f6fe SB |
468 | struct occr *occr; |
469 | ||
470 | fprintf (file, "expr: "); | |
4a8fb1a1 LC |
471 | print_rtl (file, exprs->expr); |
472 | fprintf (file,"\nhashcode: %u\n", exprs->hash); | |
cc9795d4 | 473 | fprintf (file,"list of occurrences:\n"); |
4a8fb1a1 | 474 | occr = exprs->avail_occr; |
0516f6fe SB |
475 | while (occr) |
476 | { | |
6c6d76be | 477 | rtx_insn *insn = occr->insn; |
0516f6fe SB |
478 | print_rtl_single (file, insn); |
479 | fprintf (file, "\n"); | |
480 | occr = occr->next; | |
481 | } | |
482 | fprintf (file, "\n"); | |
483 | return 1; | |
484 | } | |
485 | ||
486 | static void | |
487 | dump_hash_table (FILE *file) | |
488 | { | |
489 | fprintf (file, "\n\nexpression hash table\n"); | |
490 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
c203e8a7 TS |
491 | (long) expr_table->size (), |
492 | (long) expr_table->elements (), | |
493 | expr_table->collisions ()); | |
b119c055 | 494 | if (!expr_table->is_empty ()) |
0516f6fe SB |
495 | { |
496 | fprintf (file, "\n\ntable entries:\n"); | |
c203e8a7 | 497 | expr_table->traverse <FILE *, dump_expr_hash_table_entry> (file); |
0516f6fe SB |
498 | } |
499 | fprintf (file, "\n"); | |
500 | } | |
501 | \f | |
5da20cfe RS |
502 | /* Return true if register X is recorded as being set by an instruction |
503 | whose CUID is greater than the one given. */ | |
504 | ||
505 | static bool | |
506 | reg_changed_after_insn_p (rtx x, int cuid) | |
507 | { | |
508 | unsigned int regno, end_regno; | |
509 | ||
510 | regno = REGNO (x); | |
72d19505 | 511 | end_regno = END_REGNO (x); |
5da20cfe RS |
512 | do |
513 | if (reg_avail_info[regno] > cuid) | |
514 | return true; | |
515 | while (++regno < end_regno); | |
516 | return false; | |
517 | } | |
0516f6fe | 518 | |
c93320c4 SB |
519 | /* Return nonzero if the operands of expression X are unchanged |
520 | 1) from the start of INSN's basic block up to but not including INSN | |
521 | if AFTER_INSN is false, or | |
522 | 2) from INSN to the end of INSN's basic block if AFTER_INSN is true. */ | |
0516f6fe SB |
523 | |
524 | static bool | |
6c6d76be | 525 | oprs_unchanged_p (rtx x, rtx_insn *insn, bool after_insn) |
0516f6fe SB |
526 | { |
527 | int i, j; | |
528 | enum rtx_code code; | |
529 | const char *fmt; | |
530 | ||
531 | if (x == 0) | |
532 | return 1; | |
533 | ||
534 | code = GET_CODE (x); | |
535 | switch (code) | |
536 | { | |
537 | case REG: | |
0516f6fe | 538 | /* We are called after register allocation. */ |
e16acfcd | 539 | gcc_assert (REGNO (x) < FIRST_PSEUDO_REGISTER); |
0516f6fe | 540 | if (after_insn) |
5da20cfe | 541 | return !reg_changed_after_insn_p (x, INSN_CUID (insn) - 1); |
0516f6fe | 542 | else |
5da20cfe | 543 | return !reg_changed_after_insn_p (x, 0); |
0516f6fe SB |
544 | |
545 | case MEM: | |
546 | if (load_killed_in_block_p (INSN_CUID (insn), x, after_insn)) | |
547 | return 0; | |
548 | else | |
549 | return oprs_unchanged_p (XEXP (x, 0), insn, after_insn); | |
550 | ||
551 | case PC: | |
552 | case CC0: /*FIXME*/ | |
553 | case CONST: | |
d8116890 | 554 | CASE_CONST_ANY: |
0516f6fe SB |
555 | case SYMBOL_REF: |
556 | case LABEL_REF: | |
557 | case ADDR_VEC: | |
558 | case ADDR_DIFF_VEC: | |
559 | return 1; | |
560 | ||
561 | case PRE_DEC: | |
562 | case PRE_INC: | |
563 | case POST_DEC: | |
564 | case POST_INC: | |
565 | case PRE_MODIFY: | |
566 | case POST_MODIFY: | |
567 | if (after_insn) | |
568 | return 0; | |
569 | break; | |
570 | ||
571 | default: | |
572 | break; | |
573 | } | |
574 | ||
575 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) | |
576 | { | |
577 | if (fmt[i] == 'e') | |
578 | { | |
579 | if (! oprs_unchanged_p (XEXP (x, i), insn, after_insn)) | |
580 | return 0; | |
581 | } | |
582 | else if (fmt[i] == 'E') | |
583 | for (j = 0; j < XVECLEN (x, i); j++) | |
584 | if (! oprs_unchanged_p (XVECEXP (x, i, j), insn, after_insn)) | |
585 | return 0; | |
586 | } | |
587 | ||
588 | return 1; | |
589 | } | |
590 | \f | |
591 | ||
592 | /* Used for communication between find_mem_conflicts and | |
593 | load_killed_in_block_p. Nonzero if find_mem_conflicts finds a | |
594 | conflict between two memory references. | |
595 | This is a bit of a hack to work around the limitations of note_stores. */ | |
596 | static int mems_conflict_p; | |
597 | ||
598 | /* DEST is the output of an instruction. If it is a memory reference, and | |
599 | possibly conflicts with the load found in DATA, then set mems_conflict_p | |
600 | to a nonzero value. */ | |
601 | ||
602 | static void | |
7bc980e1 | 603 | find_mem_conflicts (rtx dest, const_rtx setter ATTRIBUTE_UNUSED, |
0516f6fe SB |
604 | void *data) |
605 | { | |
606 | rtx mem_op = (rtx) data; | |
607 | ||
608 | while (GET_CODE (dest) == SUBREG | |
609 | || GET_CODE (dest) == ZERO_EXTRACT | |
0516f6fe SB |
610 | || GET_CODE (dest) == STRICT_LOW_PART) |
611 | dest = XEXP (dest, 0); | |
612 | ||
613 | /* If DEST is not a MEM, then it will not conflict with the load. Note | |
614 | that function calls are assumed to clobber memory, but are handled | |
615 | elsewhere. */ | |
616 | if (! MEM_P (dest)) | |
617 | return; | |
618 | ||
53d9622b | 619 | if (true_dependence (dest, GET_MODE (dest), mem_op)) |
0516f6fe SB |
620 | mems_conflict_p = 1; |
621 | } | |
622 | \f | |
623 | ||
624 | /* Return nonzero if the expression in X (a memory reference) is killed | |
c93320c4 SB |
625 | in the current basic block before (if AFTER_INSN is false) or after |
626 | (if AFTER_INSN is true) the insn with the CUID in UID_LIMIT. | |
627 | ||
628 | This function assumes that the modifies_mem table is flushed when | |
629 | the hash table construction or redundancy elimination phases start | |
630 | processing a new basic block. */ | |
0516f6fe SB |
631 | |
632 | static int | |
633 | load_killed_in_block_p (int uid_limit, rtx x, bool after_insn) | |
634 | { | |
635 | struct modifies_mem *list_entry = modifies_mem_list; | |
636 | ||
637 | while (list_entry) | |
638 | { | |
6c6d76be | 639 | rtx_insn *setter = list_entry->insn; |
0516f6fe SB |
640 | |
641 | /* Ignore entries in the list that do not apply. */ | |
642 | if ((after_insn | |
643 | && INSN_CUID (setter) < uid_limit) | |
644 | || (! after_insn | |
645 | && INSN_CUID (setter) > uid_limit)) | |
646 | { | |
647 | list_entry = list_entry->next; | |
648 | continue; | |
649 | } | |
650 | ||
651 | /* If SETTER is a call everything is clobbered. Note that calls | |
652 | to pure functions are never put on the list, so we need not | |
653 | worry about them. */ | |
654 | if (CALL_P (setter)) | |
655 | return 1; | |
656 | ||
657 | /* SETTER must be an insn of some kind that sets memory. Call | |
658 | note_stores to examine each hunk of memory that is modified. | |
659 | It will set mems_conflict_p to nonzero if there may be a | |
660 | conflict between X and SETTER. */ | |
661 | mems_conflict_p = 0; | |
e8448ba5 | 662 | note_stores (setter, find_mem_conflicts, x); |
0516f6fe SB |
663 | if (mems_conflict_p) |
664 | return 1; | |
665 | ||
666 | list_entry = list_entry->next; | |
667 | } | |
668 | return 0; | |
669 | } | |
670 | \f | |
671 | ||
672 | /* Record register first/last/block set information for REGNO in INSN. */ | |
673 | ||
c93320c4 | 674 | static inline void |
6c6d76be | 675 | record_last_reg_set_info (rtx_insn *insn, rtx reg) |
6994f254 MM |
676 | { |
677 | unsigned int regno, end_regno; | |
678 | ||
679 | regno = REGNO (reg); | |
72d19505 | 680 | end_regno = END_REGNO (reg); |
6994f254 MM |
681 | do |
682 | reg_avail_info[regno] = INSN_CUID (insn); | |
683 | while (++regno < end_regno); | |
684 | } | |
685 | ||
686 | static inline void | |
6c6d76be | 687 | record_last_reg_set_info_regno (rtx_insn *insn, int regno) |
0516f6fe SB |
688 | { |
689 | reg_avail_info[regno] = INSN_CUID (insn); | |
690 | } | |
691 | ||
692 | ||
693 | /* Record memory modification information for INSN. We do not actually care | |
694 | about the memory location(s) that are set, or even how they are set (consider | |
695 | a CALL_INSN). We merely need to record which insns modify memory. */ | |
696 | ||
697 | static void | |
6c6d76be | 698 | record_last_mem_set_info (rtx_insn *insn) |
0516f6fe SB |
699 | { |
700 | struct modifies_mem *list_entry; | |
701 | ||
702 | list_entry = (struct modifies_mem *) obstack_alloc (&modifies_mem_obstack, | |
703 | sizeof (struct modifies_mem)); | |
704 | list_entry->insn = insn; | |
705 | list_entry->next = modifies_mem_list; | |
706 | modifies_mem_list = list_entry; | |
af3eb110 JL |
707 | |
708 | record_last_mem_set_info_common (insn, modify_mem_list, | |
709 | canon_modify_mem_list, | |
710 | modify_mem_list_set, | |
711 | blocks_with_calls); | |
0516f6fe SB |
712 | } |
713 | ||
714 | /* Called from compute_hash_table via note_stores to handle one | |
715 | SET or CLOBBER in an insn. DATA is really the instruction in which | |
716 | the SET is taking place. */ | |
717 | ||
718 | static void | |
7bc980e1 | 719 | record_last_set_info (rtx dest, const_rtx setter ATTRIBUTE_UNUSED, void *data) |
0516f6fe | 720 | { |
6c6d76be | 721 | rtx_insn *last_set_insn = (rtx_insn *) data; |
0516f6fe SB |
722 | |
723 | if (GET_CODE (dest) == SUBREG) | |
724 | dest = SUBREG_REG (dest); | |
725 | ||
726 | if (REG_P (dest)) | |
6994f254 | 727 | record_last_reg_set_info (last_set_insn, dest); |
56038245 SB |
728 | else if (MEM_P (dest)) |
729 | { | |
730 | /* Ignore pushes, they don't clobber memory. They may still | |
731 | clobber the stack pointer though. Some targets do argument | |
732 | pushes without adding REG_INC notes. See e.g. PR25196, | |
733 | where a pushsi2 on i386 doesn't have REG_INC notes. Note | |
734 | such changes here too. */ | |
735 | if (! push_operand (dest, GET_MODE (dest))) | |
736 | record_last_mem_set_info (last_set_insn); | |
737 | else | |
6994f254 | 738 | record_last_reg_set_info_regno (last_set_insn, STACK_POINTER_REGNUM); |
56038245 | 739 | } |
0516f6fe | 740 | } |
c93320c4 | 741 | |
0516f6fe SB |
742 | |
743 | /* Reset tables used to keep track of what's still available since the | |
744 | start of the block. */ | |
745 | ||
746 | static void | |
747 | reset_opr_set_tables (void) | |
748 | { | |
749 | memset (reg_avail_info, 0, FIRST_PSEUDO_REGISTER * sizeof (int)); | |
750 | obstack_free (&modifies_mem_obstack, modifies_mem_obstack_bottom); | |
751 | modifies_mem_list = NULL; | |
752 | } | |
c93320c4 | 753 | \f |
0516f6fe SB |
754 | |
755 | /* Record things set by INSN. | |
756 | This data is used by oprs_unchanged_p. */ | |
757 | ||
758 | static void | |
6c6d76be | 759 | record_opr_changes (rtx_insn *insn) |
0516f6fe | 760 | { |
c93320c4 | 761 | rtx note; |
0516f6fe | 762 | |
c93320c4 | 763 | /* Find all stores and record them. */ |
e8448ba5 | 764 | note_stores (insn, record_last_set_info, insn); |
0516f6fe | 765 | |
c93320c4 SB |
766 | /* Also record autoincremented REGs for this insn as changed. */ |
767 | for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) | |
768 | if (REG_NOTE_KIND (note) == REG_INC) | |
6994f254 | 769 | record_last_reg_set_info (insn, XEXP (note, 0)); |
0516f6fe | 770 | |
c93320c4 SB |
771 | /* Finally, if this is a call, record all call clobbers. */ |
772 | if (CALL_P (insn)) | |
773 | { | |
6994f254 | 774 | unsigned int regno; |
c7fb4c7a | 775 | hard_reg_set_iterator hrsi; |
7187286e RS |
776 | /* We don't track modes of hard registers, so we need to be |
777 | conservative and assume that partial kills are full kills. */ | |
778 | HARD_REG_SET callee_clobbers | |
779 | = insn_callee_abi (insn).full_and_partial_reg_clobbers (); | |
780 | EXECUTE_IF_SET_IN_HARD_REG_SET (callee_clobbers, 0, regno, hrsi) | |
c7fb4c7a | 781 | record_last_reg_set_info_regno (insn, regno); |
0516f6fe | 782 | |
becfd6e5 | 783 | if (! RTL_CONST_OR_PURE_CALL_P (insn)) |
c93320c4 SB |
784 | record_last_mem_set_info (insn); |
785 | } | |
0516f6fe SB |
786 | } |
787 | \f | |
788 | ||
789 | /* Scan the pattern of INSN and add an entry to the hash TABLE. | |
790 | After reload we are interested in loads/stores only. */ | |
791 | ||
792 | static void | |
6c6d76be | 793 | hash_scan_set (rtx_insn *insn) |
0516f6fe SB |
794 | { |
795 | rtx pat = PATTERN (insn); | |
796 | rtx src = SET_SRC (pat); | |
797 | rtx dest = SET_DEST (pat); | |
798 | ||
799 | /* We are only interested in loads and stores. */ | |
800 | if (! MEM_P (src) && ! MEM_P (dest)) | |
801 | return; | |
802 | ||
803 | /* Don't mess with jumps and nops. */ | |
804 | if (JUMP_P (insn) || set_noop_p (pat)) | |
805 | return; | |
806 | ||
0516f6fe SB |
807 | if (REG_P (dest)) |
808 | { | |
c93320c4 | 809 | if (/* Don't CSE something if we can't do a reg/reg copy. */ |
0516f6fe SB |
810 | can_copy_p (GET_MODE (dest)) |
811 | /* Is SET_SRC something we want to gcse? */ | |
812 | && general_operand (src, GET_MODE (src)) | |
a3f4b7d8 SB |
813 | #ifdef STACK_REGS |
814 | /* Never consider insns touching the register stack. It may | |
815 | create situations that reg-stack cannot handle (e.g. a stack | |
816 | register live across an abnormal edge). */ | |
817 | && (REGNO (dest) < FIRST_STACK_REG || REGNO (dest) > LAST_STACK_REG) | |
818 | #endif | |
0516f6fe SB |
819 | /* An expression is not available if its operands are |
820 | subsequently modified, including this insn. */ | |
821 | && oprs_unchanged_p (src, insn, true)) | |
822 | { | |
823 | insert_expr_in_table (src, insn); | |
824 | } | |
825 | } | |
826 | else if (REG_P (src)) | |
827 | { | |
828 | /* Only record sets of pseudo-regs in the hash table. */ | |
c93320c4 | 829 | if (/* Don't CSE something if we can't do a reg/reg copy. */ |
0516f6fe SB |
830 | can_copy_p (GET_MODE (src)) |
831 | /* Is SET_DEST something we want to gcse? */ | |
832 | && general_operand (dest, GET_MODE (dest)) | |
a3f4b7d8 SB |
833 | #ifdef STACK_REGS |
834 | /* As above for STACK_REGS. */ | |
835 | && (REGNO (src) < FIRST_STACK_REG || REGNO (src) > LAST_STACK_REG) | |
836 | #endif | |
0516f6fe SB |
837 | && ! (flag_float_store && FLOAT_MODE_P (GET_MODE (dest))) |
838 | /* Check if the memory expression is killed after insn. */ | |
839 | && ! load_killed_in_block_p (INSN_CUID (insn) + 1, dest, true) | |
840 | && oprs_unchanged_p (XEXP (dest, 0), insn, true)) | |
841 | { | |
842 | insert_expr_in_table (dest, insn); | |
843 | } | |
844 | } | |
845 | } | |
846 | \f | |
c93320c4 | 847 | |
0516f6fe | 848 | /* Create hash table of memory expressions available at end of basic |
c93320c4 SB |
849 | blocks. Basically you should think of this hash table as the |
850 | representation of AVAIL_OUT. This is the set of expressions that | |
851 | is generated in a basic block and not killed before the end of the | |
852 | same basic block. Notice that this is really a local computation. */ | |
0516f6fe SB |
853 | |
854 | static void | |
855 | compute_hash_table (void) | |
856 | { | |
857 | basic_block bb; | |
858 | ||
11cd3bed | 859 | FOR_EACH_BB_FN (bb, cfun) |
0516f6fe | 860 | { |
6c6d76be | 861 | rtx_insn *insn; |
0516f6fe SB |
862 | |
863 | /* First pass over the instructions records information used to | |
c93320c4 SB |
864 | determine when registers and memory are last set. |
865 | Since we compute a "local" AVAIL_OUT, reset the tables that | |
866 | help us keep track of what has been modified since the start | |
867 | of the block. */ | |
868 | reset_opr_set_tables (); | |
0516f6fe SB |
869 | FOR_BB_INSNS (bb, insn) |
870 | { | |
c93320c4 SB |
871 | if (INSN_P (insn)) |
872 | record_opr_changes (insn); | |
873 | } | |
0516f6fe | 874 | |
c93320c4 | 875 | /* The next pass actually builds the hash table. */ |
0516f6fe SB |
876 | FOR_BB_INSNS (bb, insn) |
877 | if (INSN_P (insn) && GET_CODE (PATTERN (insn)) == SET) | |
878 | hash_scan_set (insn); | |
879 | } | |
880 | } | |
881 | \f | |
882 | ||
883 | /* Check if register REG is killed in any insn waiting to be inserted on | |
884 | edge E. This function is required to check that our data flow analysis | |
885 | is still valid prior to commit_edge_insertions. */ | |
886 | ||
887 | static bool | |
888 | reg_killed_on_edge (rtx reg, edge e) | |
889 | { | |
3ffa95c2 | 890 | rtx_insn *insn; |
0516f6fe SB |
891 | |
892 | for (insn = e->insns.r; insn; insn = NEXT_INSN (insn)) | |
893 | if (INSN_P (insn) && reg_set_p (reg, insn)) | |
894 | return true; | |
895 | ||
896 | return false; | |
897 | } | |
898 | ||
899 | /* Similar to above - check if register REG is used in any insn waiting | |
900 | to be inserted on edge E. | |
901 | Assumes no such insn can be a CALL_INSN; if so call reg_used_between_p | |
902 | with PREV(insn),NEXT(insn) instead of calling reg_overlap_mentioned_p. */ | |
903 | ||
904 | static bool | |
905 | reg_used_on_edge (rtx reg, edge e) | |
906 | { | |
3ffa95c2 | 907 | rtx_insn *insn; |
0516f6fe SB |
908 | |
909 | for (insn = e->insns.r; insn; insn = NEXT_INSN (insn)) | |
910 | if (INSN_P (insn) && reg_overlap_mentioned_p (reg, PATTERN (insn))) | |
911 | return true; | |
912 | ||
913 | return false; | |
914 | } | |
915 | \f | |
0516f6fe SB |
916 | /* Return the loaded/stored register of a load/store instruction. */ |
917 | ||
918 | static rtx | |
6c6d76be | 919 | get_avail_load_store_reg (rtx_insn *insn) |
0516f6fe | 920 | { |
e16acfcd NS |
921 | if (REG_P (SET_DEST (PATTERN (insn)))) |
922 | /* A load. */ | |
c3284718 | 923 | return SET_DEST (PATTERN (insn)); |
e16acfcd NS |
924 | else |
925 | { | |
926 | /* A store. */ | |
927 | gcc_assert (REG_P (SET_SRC (PATTERN (insn)))); | |
928 | return SET_SRC (PATTERN (insn)); | |
929 | } | |
0516f6fe SB |
930 | } |
931 | ||
932 | /* Return nonzero if the predecessors of BB are "well behaved". */ | |
933 | ||
934 | static bool | |
935 | bb_has_well_behaved_predecessors (basic_block bb) | |
936 | { | |
937 | edge pred; | |
628f6a4e | 938 | edge_iterator ei; |
0516f6fe | 939 | |
76015c34 | 940 | if (EDGE_COUNT (bb->preds) == 0) |
0516f6fe SB |
941 | return false; |
942 | ||
628f6a4e | 943 | FOR_EACH_EDGE (pred, ei, bb->preds) |
0516f6fe | 944 | { |
8fa37232 EB |
945 | /* commit_one_edge_insertion refuses to insert on abnormal edges even if |
946 | the source has only one successor so EDGE_CRITICAL_P is too weak. */ | |
947 | if ((pred->flags & EDGE_ABNORMAL) && !single_pred_p (pred->dest)) | |
0516f6fe SB |
948 | return false; |
949 | ||
76015c34 EB |
950 | if ((pred->flags & EDGE_ABNORMAL_CALL) && cfun->has_nonlocal_label) |
951 | return false; | |
952 | ||
39718607 | 953 | if (tablejump_p (BB_END (pred->src), NULL, NULL)) |
0516f6fe SB |
954 | return false; |
955 | } | |
956 | return true; | |
957 | } | |
958 | ||
959 | ||
960 | /* Search for the occurrences of expression in BB. */ | |
961 | ||
962 | static struct occr* | |
af3eb110 | 963 | get_bb_avail_insn (basic_block bb, struct occr *orig_occr, int bitmap_index) |
0516f6fe | 964 | { |
af3eb110 JL |
965 | struct occr *occr = orig_occr; |
966 | ||
0516f6fe SB |
967 | for (; occr != NULL; occr = occr->next) |
968 | if (BLOCK_FOR_INSN (occr->insn) == bb) | |
969 | return occr; | |
af3eb110 JL |
970 | |
971 | /* If we could not find an occurrence in BB, see if BB | |
972 | has a single predecessor with an occurrence that is | |
973 | transparent through BB. */ | |
dc91c653 RB |
974 | if (transp |
975 | && single_pred_p (bb) | |
af3eb110 JL |
976 | && bitmap_bit_p (transp[bb->index], bitmap_index) |
977 | && (occr = get_bb_avail_insn (single_pred (bb), orig_occr, bitmap_index))) | |
978 | { | |
979 | rtx avail_reg = get_avail_load_store_reg (occr->insn); | |
980 | if (!reg_set_between_p (avail_reg, | |
981 | PREV_INSN (BB_HEAD (bb)), | |
982 | NEXT_INSN (BB_END (bb))) | |
983 | && !reg_killed_on_edge (avail_reg, single_pred_edge (bb))) | |
984 | return occr; | |
985 | } | |
986 | ||
0516f6fe SB |
987 | return NULL; |
988 | } | |
989 | ||
990 | ||
af3eb110 JL |
991 | /* This helper is called via htab_traverse. */ |
992 | int | |
993 | compute_expr_transp (expr **slot, FILE *dump_file ATTRIBUTE_UNUSED) | |
994 | { | |
995 | struct expr *expr = *slot; | |
996 | ||
997 | compute_transp (expr->expr, expr->bitmap_index, transp, | |
998 | blocks_with_calls, modify_mem_list_set, | |
999 | canon_modify_mem_list); | |
1000 | return 1; | |
1001 | } | |
1002 | ||
0516f6fe SB |
1003 | /* This handles the case where several stores feed a partially redundant |
1004 | load. It checks if the redundancy elimination is possible and if it's | |
c93320c4 SB |
1005 | worth it. |
1006 | ||
1007 | Redundancy elimination is possible if, | |
1008 | 1) None of the operands of an insn have been modified since the start | |
1009 | of the current basic block. | |
1010 | 2) In any predecessor of the current basic block, the same expression | |
1011 | is generated. | |
1012 | ||
1013 | See the function body for the heuristics that determine if eliminating | |
1014 | a redundancy is also worth doing, assuming it is possible. */ | |
0516f6fe SB |
1015 | |
1016 | static void | |
6c6d76be | 1017 | eliminate_partially_redundant_load (basic_block bb, rtx_insn *insn, |
0516f6fe SB |
1018 | struct expr *expr) |
1019 | { | |
1020 | edge pred; | |
6c6d76be | 1021 | rtx_insn *avail_insn = NULL; |
0516f6fe SB |
1022 | rtx avail_reg; |
1023 | rtx dest, pat; | |
1024 | struct occr *a_occr; | |
1025 | struct unoccr *occr, *avail_occrs = NULL; | |
1026 | struct unoccr *unoccr, *unavail_occrs = NULL, *rollback_unoccr = NULL; | |
1027 | int npred_ok = 0; | |
3995f3a2 JH |
1028 | profile_count ok_count = profile_count::zero (); |
1029 | /* Redundant load execution count. */ | |
1030 | profile_count critical_count = profile_count::zero (); | |
1031 | /* Execution count of critical edges. */ | |
628f6a4e | 1032 | edge_iterator ei; |
303f6390 | 1033 | bool critical_edge_split = false; |
0516f6fe SB |
1034 | |
1035 | /* The execution count of the loads to be added to make the | |
1036 | load fully redundant. */ | |
3995f3a2 | 1037 | profile_count not_ok_count = profile_count::zero (); |
0516f6fe SB |
1038 | basic_block pred_bb; |
1039 | ||
1040 | pat = PATTERN (insn); | |
1041 | dest = SET_DEST (pat); | |
1042 | ||
1043 | /* Check that the loaded register is not used, set, or killed from the | |
1044 | beginning of the block. */ | |
5da20cfe RS |
1045 | if (reg_changed_after_insn_p (dest, 0) |
1046 | || reg_used_between_p (dest, PREV_INSN (BB_HEAD (bb)), insn)) | |
0516f6fe SB |
1047 | return; |
1048 | ||
1049 | /* Check potential for replacing load with copy for predecessors. */ | |
628f6a4e | 1050 | FOR_EACH_EDGE (pred, ei, bb->preds) |
0516f6fe | 1051 | { |
6c6d76be | 1052 | rtx_insn *next_pred_bb_end; |
0516f6fe | 1053 | |
6c6d76be | 1054 | avail_insn = NULL; |
303f6390 | 1055 | avail_reg = NULL_RTX; |
0516f6fe | 1056 | pred_bb = pred->src; |
af3eb110 JL |
1057 | for (a_occr = get_bb_avail_insn (pred_bb, |
1058 | expr->avail_occr, | |
1059 | expr->bitmap_index); | |
1060 | a_occr; | |
1061 | a_occr = get_bb_avail_insn (pred_bb, | |
1062 | a_occr->next, | |
1063 | expr->bitmap_index)) | |
0516f6fe SB |
1064 | { |
1065 | /* Check if the loaded register is not used. */ | |
1066 | avail_insn = a_occr->insn; | |
e16acfcd NS |
1067 | avail_reg = get_avail_load_store_reg (avail_insn); |
1068 | gcc_assert (avail_reg); | |
b8698a0f | 1069 | |
0516f6fe SB |
1070 | /* Make sure we can generate a move from register avail_reg to |
1071 | dest. */ | |
1476d1bd MM |
1072 | rtx_insn *move = gen_move_insn (copy_rtx (dest), |
1073 | copy_rtx (avail_reg)); | |
daca1a96 RS |
1074 | extract_insn (move); |
1075 | if (! constrain_operands (1, get_preferred_alternatives (insn, | |
1076 | pred_bb)) | |
0516f6fe SB |
1077 | || reg_killed_on_edge (avail_reg, pred) |
1078 | || reg_used_on_edge (dest, pred)) | |
1079 | { | |
1080 | avail_insn = NULL; | |
1081 | continue; | |
1082 | } | |
af3eb110 | 1083 | next_pred_bb_end = NEXT_INSN (BB_END (BLOCK_FOR_INSN (avail_insn))); |
5da20cfe | 1084 | if (!reg_set_between_p (avail_reg, avail_insn, next_pred_bb_end)) |
0516f6fe SB |
1085 | /* AVAIL_INSN remains non-null. */ |
1086 | break; | |
1087 | else | |
1088 | avail_insn = NULL; | |
1089 | } | |
1090 | ||
ef30ab83 JH |
1091 | if (EDGE_CRITICAL_P (pred) && pred->count ().initialized_p ()) |
1092 | critical_count += pred->count (); | |
0516f6fe SB |
1093 | |
1094 | if (avail_insn != NULL_RTX) | |
1095 | { | |
1096 | npred_ok++; | |
ef30ab83 JH |
1097 | if (pred->count ().initialized_p ()) |
1098 | ok_count = ok_count + pred->count (); | |
303f6390 MH |
1099 | if (! set_noop_p (PATTERN (gen_move_insn (copy_rtx (dest), |
1100 | copy_rtx (avail_reg))))) | |
1101 | { | |
1102 | /* Check if there is going to be a split. */ | |
1103 | if (EDGE_CRITICAL_P (pred)) | |
1104 | critical_edge_split = true; | |
1105 | } | |
1106 | else /* Its a dead move no need to generate. */ | |
1107 | continue; | |
0516f6fe | 1108 | occr = (struct unoccr *) obstack_alloc (&unoccr_obstack, |
9275de65 | 1109 | sizeof (struct unoccr)); |
0516f6fe SB |
1110 | occr->insn = avail_insn; |
1111 | occr->pred = pred; | |
1112 | occr->next = avail_occrs; | |
1113 | avail_occrs = occr; | |
1114 | if (! rollback_unoccr) | |
1115 | rollback_unoccr = occr; | |
1116 | } | |
1117 | else | |
1118 | { | |
c83eecad | 1119 | /* Adding a load on a critical edge will cause a split. */ |
303f6390 MH |
1120 | if (EDGE_CRITICAL_P (pred)) |
1121 | critical_edge_split = true; | |
ef30ab83 JH |
1122 | if (pred->count ().initialized_p ()) |
1123 | not_ok_count = not_ok_count + pred->count (); | |
0516f6fe SB |
1124 | unoccr = (struct unoccr *) obstack_alloc (&unoccr_obstack, |
1125 | sizeof (struct unoccr)); | |
6c6d76be | 1126 | unoccr->insn = NULL; |
0516f6fe SB |
1127 | unoccr->pred = pred; |
1128 | unoccr->next = unavail_occrs; | |
1129 | unavail_occrs = unoccr; | |
1130 | if (! rollback_unoccr) | |
1131 | rollback_unoccr = unoccr; | |
1132 | } | |
1133 | } | |
1134 | ||
1135 | if (/* No load can be replaced by copy. */ | |
1136 | npred_ok == 0 | |
b8698a0f | 1137 | /* Prevent exploding the code. */ |
efd8f750 | 1138 | || (optimize_bb_for_size_p (bb) && npred_ok > 1) |
b8698a0f | 1139 | /* If we don't have profile information we cannot tell if splitting |
303f6390 | 1140 | a critical edge is profitable or not so don't do it. */ |
512cc015 | 1141 | || ((!profile_info || profile_status_for_fn (cfun) != PROFILE_READ |
303f6390 MH |
1142 | || targetm.cannot_modify_jumps_p ()) |
1143 | && critical_edge_split)) | |
0516f6fe SB |
1144 | goto cleanup; |
1145 | ||
1146 | /* Check if it's worth applying the partial redundancy elimination. */ | |
3995f3a2 | 1147 | if (ok_count.to_gcov_type () |
028d4092 | 1148 | < param_gcse_after_reload_partial_fraction * not_ok_count.to_gcov_type ()) |
0516f6fe | 1149 | goto cleanup; |
907050e3 ML |
1150 | |
1151 | gcov_type threshold; | |
1152 | #if (GCC_VERSION >= 5000) | |
028d4092 | 1153 | if (__builtin_mul_overflow (param_gcse_after_reload_critical_fraction, |
907050e3 ML |
1154 | critical_count.to_gcov_type (), &threshold)) |
1155 | threshold = profile_count::max_count; | |
1156 | #else | |
1157 | threshold | |
028d4092 ML |
1158 | = (param_gcse_after_reload_critical_fraction |
1159 | * critical_count.to_gcov_type ()); | |
907050e3 ML |
1160 | #endif |
1161 | ||
1162 | if (ok_count.to_gcov_type () < threshold) | |
0516f6fe SB |
1163 | goto cleanup; |
1164 | ||
1165 | /* Generate moves to the loaded register from where | |
1166 | the memory is available. */ | |
1167 | for (occr = avail_occrs; occr; occr = occr->next) | |
1168 | { | |
1169 | avail_insn = occr->insn; | |
1170 | pred = occr->pred; | |
1171 | /* Set avail_reg to be the register having the value of the | |
1172 | memory. */ | |
1173 | avail_reg = get_avail_load_store_reg (avail_insn); | |
e16acfcd | 1174 | gcc_assert (avail_reg); |
0516f6fe SB |
1175 | |
1176 | insert_insn_on_edge (gen_move_insn (copy_rtx (dest), | |
1177 | copy_rtx (avail_reg)), | |
1178 | pred); | |
1179 | stats.moves_inserted++; | |
1180 | ||
1181 | if (dump_file) | |
1182 | fprintf (dump_file, | |
1183 | "generating move from %d to %d on edge from %d to %d\n", | |
1184 | REGNO (avail_reg), | |
1185 | REGNO (dest), | |
1186 | pred->src->index, | |
1187 | pred->dest->index); | |
1188 | } | |
1189 | ||
1190 | /* Regenerate loads where the memory is unavailable. */ | |
1191 | for (unoccr = unavail_occrs; unoccr; unoccr = unoccr->next) | |
1192 | { | |
1193 | pred = unoccr->pred; | |
1194 | insert_insn_on_edge (copy_insn (PATTERN (insn)), pred); | |
1195 | stats.copies_inserted++; | |
1196 | ||
1197 | if (dump_file) | |
1198 | { | |
1199 | fprintf (dump_file, | |
1200 | "generating on edge from %d to %d a copy of load: ", | |
1201 | pred->src->index, | |
1202 | pred->dest->index); | |
1203 | print_rtl (dump_file, PATTERN (insn)); | |
1204 | fprintf (dump_file, "\n"); | |
1205 | } | |
1206 | } | |
1207 | ||
1208 | /* Delete the insn if it is not available in this block and mark it | |
1209 | for deletion if it is available. If insn is available it may help | |
1210 | discover additional redundancies, so mark it for later deletion. */ | |
af3eb110 | 1211 | for (a_occr = get_bb_avail_insn (bb, expr->avail_occr, expr->bitmap_index); |
0516f6fe | 1212 | a_occr && (a_occr->insn != insn); |
af3eb110 | 1213 | a_occr = get_bb_avail_insn (bb, a_occr->next, expr->bitmap_index)) |
e84a58ff | 1214 | ; |
0516f6fe SB |
1215 | |
1216 | if (!a_occr) | |
303f6390 MH |
1217 | { |
1218 | stats.insns_deleted++; | |
1219 | ||
1220 | if (dump_file) | |
1221 | { | |
1222 | fprintf (dump_file, "deleting insn:\n"); | |
1223 | print_rtl_single (dump_file, insn); | |
1224 | fprintf (dump_file, "\n"); | |
1225 | } | |
1226 | delete_insn (insn); | |
1227 | } | |
0516f6fe SB |
1228 | else |
1229 | a_occr->deleted_p = 1; | |
1230 | ||
1231 | cleanup: | |
1232 | if (rollback_unoccr) | |
1233 | obstack_free (&unoccr_obstack, rollback_unoccr); | |
1234 | } | |
1235 | ||
1236 | /* Performing the redundancy elimination as described before. */ | |
1237 | ||
1238 | static void | |
1239 | eliminate_partially_redundant_loads (void) | |
1240 | { | |
6c6d76be | 1241 | rtx_insn *insn; |
0516f6fe SB |
1242 | basic_block bb; |
1243 | ||
1244 | /* Note we start at block 1. */ | |
1245 | ||
fefa31b5 | 1246 | if (ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
0516f6fe SB |
1247 | return; |
1248 | ||
1249 | FOR_BB_BETWEEN (bb, | |
fefa31b5 DM |
1250 | ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->next_bb, |
1251 | EXIT_BLOCK_PTR_FOR_FN (cfun), | |
0516f6fe SB |
1252 | next_bb) |
1253 | { | |
c93320c4 | 1254 | /* Don't try anything on basic blocks with strange predecessors. */ |
0516f6fe SB |
1255 | if (! bb_has_well_behaved_predecessors (bb)) |
1256 | continue; | |
1257 | ||
c93320c4 | 1258 | /* Do not try anything on cold basic blocks. */ |
fb2fed03 | 1259 | if (optimize_bb_for_size_p (bb)) |
0516f6fe SB |
1260 | continue; |
1261 | ||
c93320c4 SB |
1262 | /* Reset the table of things changed since the start of the current |
1263 | basic block. */ | |
0516f6fe SB |
1264 | reset_opr_set_tables (); |
1265 | ||
c93320c4 SB |
1266 | /* Look at all insns in the current basic block and see if there are |
1267 | any loads in it that we can record. */ | |
0516f6fe SB |
1268 | FOR_BB_INSNS (bb, insn) |
1269 | { | |
1270 | /* Is it a load - of the form (set (reg) (mem))? */ | |
1271 | if (NONJUMP_INSN_P (insn) | |
1272 | && GET_CODE (PATTERN (insn)) == SET | |
1273 | && REG_P (SET_DEST (PATTERN (insn))) | |
1274 | && MEM_P (SET_SRC (PATTERN (insn)))) | |
1275 | { | |
1276 | rtx pat = PATTERN (insn); | |
1277 | rtx src = SET_SRC (pat); | |
1278 | struct expr *expr; | |
1279 | ||
1280 | if (!MEM_VOLATILE_P (src) | |
1281 | && GET_MODE (src) != BLKmode | |
1282 | && general_operand (src, GET_MODE (src)) | |
1283 | /* Are the operands unchanged since the start of the | |
1284 | block? */ | |
1285 | && oprs_unchanged_p (src, insn, false) | |
8f4f502f | 1286 | && !(cfun->can_throw_non_call_exceptions && may_trap_p (src)) |
0516f6fe SB |
1287 | && !side_effects_p (src) |
1288 | /* Is the expression recorded? */ | |
1289 | && (expr = lookup_expr_in_table (src)) != NULL) | |
1290 | { | |
1291 | /* We now have a load (insn) and an available memory at | |
1292 | its BB start (expr). Try to remove the loads if it is | |
1293 | redundant. */ | |
1294 | eliminate_partially_redundant_load (bb, insn, expr); | |
1295 | } | |
1296 | } | |
1297 | ||
c93320c4 SB |
1298 | /* Keep track of everything modified by this insn, so that we |
1299 | know what has been modified since the start of the current | |
1300 | basic block. */ | |
0516f6fe | 1301 | if (INSN_P (insn)) |
c93320c4 | 1302 | record_opr_changes (insn); |
0516f6fe SB |
1303 | } |
1304 | } | |
1305 | ||
1306 | commit_edge_insertions (); | |
1307 | } | |
1308 | ||
1309 | /* Go over the expression hash table and delete insns that were | |
1310 | marked for later deletion. */ | |
1311 | ||
1312 | /* This helper is called via htab_traverse. */ | |
4a8fb1a1 LC |
1313 | int |
1314 | delete_redundant_insns_1 (expr **slot, void *data ATTRIBUTE_UNUSED) | |
0516f6fe | 1315 | { |
4a8fb1a1 | 1316 | struct expr *exprs = *slot; |
0516f6fe SB |
1317 | struct occr *occr; |
1318 | ||
4a8fb1a1 | 1319 | for (occr = exprs->avail_occr; occr != NULL; occr = occr->next) |
0516f6fe | 1320 | { |
6fb5fa3c | 1321 | if (occr->deleted_p && dbg_cnt (gcse2_delete)) |
0516f6fe SB |
1322 | { |
1323 | delete_insn (occr->insn); | |
1324 | stats.insns_deleted++; | |
1325 | ||
1326 | if (dump_file) | |
1327 | { | |
1328 | fprintf (dump_file, "deleting insn:\n"); | |
1329 | print_rtl_single (dump_file, occr->insn); | |
1330 | fprintf (dump_file, "\n"); | |
1331 | } | |
1332 | } | |
1333 | } | |
1334 | ||
1335 | return 1; | |
1336 | } | |
1337 | ||
1338 | static void | |
1339 | delete_redundant_insns (void) | |
1340 | { | |
c203e8a7 | 1341 | expr_table->traverse <void *, delete_redundant_insns_1> (NULL); |
0516f6fe SB |
1342 | if (dump_file) |
1343 | fprintf (dump_file, "\n"); | |
1344 | } | |
1345 | ||
1346 | /* Main entry point of the GCSE after reload - clean some redundant loads | |
1347 | due to spilling. */ | |
1348 | ||
6e9ca1fa | 1349 | static void |
0516f6fe SB |
1350 | gcse_after_reload_main (rtx f ATTRIBUTE_UNUSED) |
1351 | { | |
dc91c653 RB |
1352 | /* Disable computing transparentness if it is too expensive. */ |
1353 | bool do_transp | |
1354 | = !gcse_or_cprop_is_too_expensive (_("using simple load CSE after register " | |
1355 | "allocation")); | |
3f55b339 | 1356 | |
0516f6fe SB |
1357 | memset (&stats, 0, sizeof (stats)); |
1358 | ||
fa10beec | 1359 | /* Allocate memory for this pass. |
0516f6fe SB |
1360 | Also computes and initializes the insns' CUIDs. */ |
1361 | alloc_mem (); | |
1362 | ||
1363 | /* We need alias analysis. */ | |
1364 | init_alias_analysis (); | |
1365 | ||
1366 | compute_hash_table (); | |
1367 | ||
1368 | if (dump_file) | |
1369 | dump_hash_table (dump_file); | |
1370 | ||
b119c055 | 1371 | if (!expr_table->is_empty ()) |
0516f6fe | 1372 | { |
af3eb110 JL |
1373 | /* Knowing which MEMs are transparent through a block can signifiantly |
1374 | increase the number of redundant loads found. So compute transparency | |
1375 | information for each memory expression in the hash table. */ | |
1376 | df_analyze (); | |
dc91c653 RB |
1377 | if (do_transp) |
1378 | { | |
1379 | /* This cannot be part of the normal allocation routine because | |
1380 | we have to know the number of elements in the hash table. */ | |
1381 | transp = sbitmap_vector_alloc (last_basic_block_for_fn (cfun), | |
1382 | expr_table->elements ()); | |
1383 | bitmap_vector_ones (transp, last_basic_block_for_fn (cfun)); | |
1384 | expr_table->traverse <FILE *, compute_expr_transp> (dump_file); | |
1385 | } | |
1386 | else | |
1387 | transp = NULL; | |
0516f6fe SB |
1388 | eliminate_partially_redundant_loads (); |
1389 | delete_redundant_insns (); | |
dc91c653 RB |
1390 | if (do_transp) |
1391 | sbitmap_vector_free (transp); | |
0516f6fe SB |
1392 | |
1393 | if (dump_file) | |
1394 | { | |
1395 | fprintf (dump_file, "GCSE AFTER RELOAD stats:\n"); | |
1396 | fprintf (dump_file, "copies inserted: %d\n", stats.copies_inserted); | |
1397 | fprintf (dump_file, "moves inserted: %d\n", stats.moves_inserted); | |
1398 | fprintf (dump_file, "insns deleted: %d\n", stats.insns_deleted); | |
1399 | fprintf (dump_file, "\n\n"); | |
1400 | } | |
4da3b811 NF |
1401 | |
1402 | statistics_counter_event (cfun, "copies inserted", | |
1403 | stats.copies_inserted); | |
1404 | statistics_counter_event (cfun, "moves inserted", | |
1405 | stats.moves_inserted); | |
1406 | statistics_counter_event (cfun, "insns deleted", | |
1407 | stats.insns_deleted); | |
0516f6fe | 1408 | } |
b8698a0f | 1409 | |
0516f6fe SB |
1410 | /* We are finished with alias. */ |
1411 | end_alias_analysis (); | |
1412 | ||
1413 | free_mem (); | |
1414 | } | |
1415 | ||
ef330312 | 1416 | \f |
ef330312 | 1417 | |
c2924966 | 1418 | static unsigned int |
ef330312 PB |
1419 | rest_of_handle_gcse2 (void) |
1420 | { | |
1421 | gcse_after_reload_main (get_insns ()); | |
1422 | rebuild_jump_labels (get_insns ()); | |
c2924966 | 1423 | return 0; |
ef330312 PB |
1424 | } |
1425 | ||
27a4cd48 DM |
1426 | namespace { |
1427 | ||
1428 | const pass_data pass_data_gcse2 = | |
ef330312 | 1429 | { |
27a4cd48 DM |
1430 | RTL_PASS, /* type */ |
1431 | "gcse2", /* name */ | |
1432 | OPTGROUP_NONE, /* optinfo_flags */ | |
27a4cd48 DM |
1433 | TV_GCSE_AFTER_RELOAD, /* tv_id */ |
1434 | 0, /* properties_required */ | |
1435 | 0, /* properties_provided */ | |
1436 | 0, /* properties_destroyed */ | |
1437 | 0, /* todo_flags_start */ | |
3bea341f | 1438 | 0, /* todo_flags_finish */ |
ef330312 | 1439 | }; |
27a4cd48 DM |
1440 | |
1441 | class pass_gcse2 : public rtl_opt_pass | |
1442 | { | |
1443 | public: | |
c3284718 RS |
1444 | pass_gcse2 (gcc::context *ctxt) |
1445 | : rtl_opt_pass (pass_data_gcse2, ctxt) | |
27a4cd48 DM |
1446 | {} |
1447 | ||
1448 | /* opt_pass methods: */ | |
1a3d085c TS |
1449 | virtual bool gate (function *fun) |
1450 | { | |
1451 | return (optimize > 0 && flag_gcse_after_reload | |
1452 | && optimize_function_for_speed_p (fun)); | |
1453 | } | |
1454 | ||
be55bfe6 | 1455 | virtual unsigned int execute (function *) { return rest_of_handle_gcse2 (); } |
27a4cd48 DM |
1456 | |
1457 | }; // class pass_gcse2 | |
1458 | ||
1459 | } // anon namespace | |
1460 | ||
1461 | rtl_opt_pass * | |
1462 | make_pass_gcse2 (gcc::context *ctxt) | |
1463 | { | |
1464 | return new pass_gcse2 (ctxt); | |
1465 | } |