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6fb5fa3c | 1 | /* RTL dead store elimination. |
fa10beec | 2 | Copyright (C) 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
6fb5fa3c DB |
3 | |
4 | Contributed by Richard Sandiford <rsandifor@codesourcery.com> | |
5 | and Kenneth Zadeck <zadeck@naturalbridge.com> | |
6 | ||
7 | This file is part of GCC. | |
8 | ||
9 | GCC is free software; you can redistribute it and/or modify it under | |
10 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 11 | Software Foundation; either version 3, or (at your option) any later |
6fb5fa3c DB |
12 | version. |
13 | ||
14 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
15 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
16 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
17 | for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
20 | along with GCC; see the file COPYING3. If not see |
21 | <http://www.gnu.org/licenses/>. */ | |
6fb5fa3c DB |
22 | |
23 | #undef BASELINE | |
24 | ||
25 | #include "config.h" | |
26 | #include "system.h" | |
27 | #include "coretypes.h" | |
28 | #include "hashtab.h" | |
29 | #include "tm.h" | |
30 | #include "rtl.h" | |
31 | #include "tree.h" | |
18b526e8 | 32 | #include "tm_p.h" |
6fb5fa3c DB |
33 | #include "regs.h" |
34 | #include "hard-reg-set.h" | |
35 | #include "flags.h" | |
36 | #include "df.h" | |
37 | #include "cselib.h" | |
38 | #include "timevar.h" | |
39 | #include "tree-pass.h" | |
40 | #include "alloc-pool.h" | |
41 | #include "alias.h" | |
42 | #include "insn-config.h" | |
43 | #include "expr.h" | |
44 | #include "recog.h" | |
45 | #include "dse.h" | |
8660aaae | 46 | #include "optabs.h" |
6fb5fa3c DB |
47 | #include "dbgcnt.h" |
48 | ||
49 | /* This file contains three techniques for performing Dead Store | |
50 | Elimination (dse). | |
51 | ||
52 | * The first technique performs dse locally on any base address. It | |
53 | is based on the cselib which is a local value numbering technique. | |
54 | This technique is local to a basic block but deals with a fairly | |
55 | general addresses. | |
56 | ||
57 | * The second technique performs dse globally but is restricted to | |
58 | base addresses that are either constant or are relative to the | |
59 | frame_pointer. | |
60 | ||
61 | * The third technique, (which is only done after register allocation) | |
62 | processes the spill spill slots. This differs from the second | |
63 | technique because it takes advantage of the fact that spilling is | |
64 | completely free from the effects of aliasing. | |
65 | ||
66 | Logically, dse is a backwards dataflow problem. A store can be | |
67 | deleted if it if cannot be reached in the backward direction by any | |
68 | use of the value being stored. However, the local technique uses a | |
69 | forwards scan of the basic block because cselib requires that the | |
70 | block be processed in that order. | |
71 | ||
72 | The pass is logically broken into 7 steps: | |
73 | ||
74 | 0) Initialization. | |
75 | ||
76 | 1) The local algorithm, as well as scanning the insns for the two | |
77 | global algorithms. | |
78 | ||
79 | 2) Analysis to see if the global algs are necessary. In the case | |
80 | of stores base on a constant address, there must be at least two | |
81 | stores to that address, to make it possible to delete some of the | |
82 | stores. In the case of stores off of the frame or spill related | |
83 | stores, only one store to an address is necessary because those | |
84 | stores die at the end of the function. | |
85 | ||
86 | 3) Set up the global dataflow equations based on processing the | |
87 | info parsed in the first step. | |
88 | ||
89 | 4) Solve the dataflow equations. | |
90 | ||
91 | 5) Delete the insns that the global analysis has indicated are | |
92 | unnecessary. | |
93 | ||
94 | 6) Cleanup. | |
95 | ||
96 | This step uses cselib and canon_rtx to build the largest expression | |
97 | possible for each address. This pass is a forwards pass through | |
98 | each basic block. From the point of view of the global technique, | |
99 | the first pass could examine a block in either direction. The | |
0d52bcc1 | 100 | forwards ordering is to accommodate cselib. |
6fb5fa3c DB |
101 | |
102 | We a simplifying assumption: addresses fall into four broad | |
103 | categories: | |
104 | ||
105 | 1) base has rtx_varies_p == false, offset is constant. | |
106 | 2) base has rtx_varies_p == false, offset variable. | |
107 | 3) base has rtx_varies_p == true, offset constant. | |
108 | 4) base has rtx_varies_p == true, offset variable. | |
109 | ||
110 | The local passes are able to process all 4 kinds of addresses. The | |
111 | global pass only handles (1). | |
112 | ||
113 | The global problem is formulated as follows: | |
114 | ||
115 | A store, S1, to address A, where A is not relative to the stack | |
116 | frame, can be eliminated if all paths from S1 to the end of the | |
117 | of the function contain another store to A before a read to A. | |
118 | ||
119 | If the address A is relative to the stack frame, a store S2 to A | |
120 | can be eliminated if there are no paths from S1 that reach the | |
121 | end of the function that read A before another store to A. In | |
122 | this case S2 can be deleted if there are paths to from S2 to the | |
123 | end of the function that have no reads or writes to A. This | |
124 | second case allows stores to the stack frame to be deleted that | |
125 | would otherwise die when the function returns. This cannot be | |
126 | done if stores_off_frame_dead_at_return is not true. See the doc | |
127 | for that variable for when this variable is false. | |
128 | ||
129 | The global problem is formulated as a backwards set union | |
130 | dataflow problem where the stores are the gens and reads are the | |
131 | kills. Set union problems are rare and require some special | |
132 | handling given our representation of bitmaps. A straightforward | |
133 | implementation of requires a lot of bitmaps filled with 1s. | |
134 | These are expensive and cumbersome in our bitmap formulation so | |
135 | care has been taken to avoid large vectors filled with 1s. See | |
136 | the comments in bb_info and in the dataflow confluence functions | |
137 | for details. | |
138 | ||
139 | There are two places for further enhancements to this algorithm: | |
140 | ||
141 | 1) The original dse which was embedded in a pass called flow also | |
142 | did local address forwarding. For example in | |
143 | ||
144 | A <- r100 | |
145 | ... <- A | |
146 | ||
147 | flow would replace the right hand side of the second insn with a | |
6ed3da00 | 148 | reference to r100. Most of the information is available to add this |
6fb5fa3c DB |
149 | to this pass. It has not done it because it is a lot of work in |
150 | the case that either r100 is assigned to between the first and | |
151 | second insn and/or the second insn is a load of part of the value | |
152 | stored by the first insn. | |
153 | ||
154 | insn 5 in gcc.c-torture/compile/990203-1.c simple case. | |
155 | insn 15 in gcc.c-torture/execute/20001017-2.c simple case. | |
156 | insn 25 in gcc.c-torture/execute/20001026-1.c simple case. | |
157 | insn 44 in gcc.c-torture/execute/20010910-1.c simple case. | |
158 | ||
159 | 2) The cleaning up of spill code is quite profitable. It currently | |
160 | depends on reading tea leaves and chicken entrails left by reload. | |
161 | This pass depends on reload creating a singleton alias set for each | |
162 | spill slot and telling the next dse pass which of these alias sets | |
163 | are the singletons. Rather than analyze the addresses of the | |
164 | spills, dse's spill processing just does analysis of the loads and | |
165 | stores that use those alias sets. There are three cases where this | |
166 | falls short: | |
167 | ||
168 | a) Reload sometimes creates the slot for one mode of access, and | |
169 | then inserts loads and/or stores for a smaller mode. In this | |
170 | case, the current code just punts on the slot. The proper thing | |
171 | to do is to back out and use one bit vector position for each | |
172 | byte of the entity associated with the slot. This depends on | |
173 | KNOWING that reload always generates the accesses for each of the | |
174 | bytes in some canonical (read that easy to understand several | |
175 | passes after reload happens) way. | |
176 | ||
177 | b) Reload sometimes decides that spill slot it allocated was not | |
178 | large enough for the mode and goes back and allocates more slots | |
179 | with the same mode and alias set. The backout in this case is a | |
180 | little more graceful than (a). In this case the slot is unmarked | |
181 | as being a spill slot and if final address comes out to be based | |
182 | off the frame pointer, the global algorithm handles this slot. | |
183 | ||
184 | c) For any pass that may prespill, there is currently no | |
185 | mechanism to tell the dse pass that the slot being used has the | |
186 | special properties that reload uses. It may be that all that is | |
0d52bcc1 | 187 | required is to have those passes make the same calls that reload |
6fb5fa3c DB |
188 | does, assuming that the alias sets can be manipulated in the same |
189 | way. */ | |
190 | ||
191 | /* There are limits to the size of constant offsets we model for the | |
192 | global problem. There are certainly test cases, that exceed this | |
193 | limit, however, it is unlikely that there are important programs | |
194 | that really have constant offsets this size. */ | |
195 | #define MAX_OFFSET (64 * 1024) | |
196 | ||
197 | ||
198 | static bitmap scratch = NULL; | |
199 | struct insn_info; | |
200 | ||
201 | /* This structure holds information about a candidate store. */ | |
202 | struct store_info | |
203 | { | |
204 | ||
205 | /* False means this is a clobber. */ | |
206 | bool is_set; | |
207 | ||
208 | /* The id of the mem group of the base address. If rtx_varies_p is | |
209 | true, this is -1. Otherwise, it is the index into the group | |
210 | table. */ | |
211 | int group_id; | |
212 | ||
213 | /* This is the cselib value. */ | |
214 | cselib_val *cse_base; | |
215 | ||
216 | /* This canonized mem. */ | |
217 | rtx mem; | |
218 | ||
219 | /* The result of get_addr on mem. */ | |
220 | rtx mem_addr; | |
221 | ||
222 | /* If this is non-zero, it is the alias set of a spill location. */ | |
4862826d | 223 | alias_set_type alias_set; |
6fb5fa3c DB |
224 | |
225 | /* The offset of the first and byte before the last byte associated | |
226 | with the operation. */ | |
227 | int begin, end; | |
228 | ||
229 | /* An bitmask as wide as the number of bytes in the word that | |
230 | contains a 1 if the byte may be needed. The store is unused if | |
231 | all of the bits are 0. */ | |
4fe663b0 | 232 | unsigned HOST_WIDE_INT positions_needed; |
6fb5fa3c DB |
233 | |
234 | /* The next store info for this insn. */ | |
235 | struct store_info *next; | |
236 | ||
237 | /* The right hand side of the store. This is used if there is a | |
238 | subsequent reload of the mems address somewhere later in the | |
239 | basic block. */ | |
240 | rtx rhs; | |
241 | }; | |
242 | ||
4fe663b0 L |
243 | /* Return a bitmask with the first N low bits set. */ |
244 | ||
245 | static unsigned HOST_WIDE_INT | |
246 | lowpart_bitmask (int n) | |
247 | { | |
248 | unsigned HOST_WIDE_INT mask = ~(unsigned HOST_WIDE_INT) 0; | |
249 | return mask >> (HOST_BITS_PER_WIDE_INT - n); | |
250 | } | |
251 | ||
6fb5fa3c DB |
252 | typedef struct store_info *store_info_t; |
253 | static alloc_pool cse_store_info_pool; | |
254 | static alloc_pool rtx_store_info_pool; | |
255 | ||
256 | /* This structure holds information about a load. These are only | |
257 | built for rtx bases. */ | |
258 | struct read_info | |
259 | { | |
260 | /* The id of the mem group of the base address. */ | |
261 | int group_id; | |
262 | ||
263 | /* If this is non-zero, it is the alias set of a spill location. */ | |
4862826d | 264 | alias_set_type alias_set; |
6fb5fa3c DB |
265 | |
266 | /* The offset of the first and byte after the last byte associated | |
267 | with the operation. If begin == end == 0, the read did not have | |
268 | a constant offset. */ | |
269 | int begin, end; | |
270 | ||
271 | /* The mem being read. */ | |
272 | rtx mem; | |
273 | ||
274 | /* The next read_info for this insn. */ | |
275 | struct read_info *next; | |
276 | }; | |
277 | typedef struct read_info *read_info_t; | |
278 | static alloc_pool read_info_pool; | |
279 | ||
280 | ||
281 | /* One of these records is created for each insn. */ | |
282 | ||
283 | struct insn_info | |
284 | { | |
285 | /* Set true if the insn contains a store but the insn itself cannot | |
286 | be deleted. This is set if the insn is a parallel and there is | |
287 | more than one non dead output or if the insn is in some way | |
288 | volatile. */ | |
289 | bool cannot_delete; | |
290 | ||
291 | /* This field is only used by the global algorithm. It is set true | |
292 | if the insn contains any read of mem except for a (1). This is | |
293 | also set if the insn is a call or has a clobber mem. If the insn | |
294 | contains a wild read, the use_rec will be null. */ | |
295 | bool wild_read; | |
296 | ||
50f0f366 EB |
297 | /* This field is only used for the processing of const functions. |
298 | These functions cannot read memory, but they can read the stack | |
64520bdc EB |
299 | because that is where they may get their parms. We need to be |
300 | this conservative because, like the store motion pass, we don't | |
301 | consider CALL_INSN_FUNCTION_USAGE when processing call insns. | |
302 | Moreover, we need to distinguish two cases: | |
303 | 1. Before reload (register elimination), the stores related to | |
304 | outgoing arguments are stack pointer based and thus deemed | |
305 | of non-constant base in this pass. This requires special | |
306 | handling but also means that the frame pointer based stores | |
307 | need not be killed upon encountering a const function call. | |
308 | 2. After reload, the stores related to outgoing arguments can be | |
309 | either stack pointer or hard frame pointer based. This means | |
310 | that we have no other choice than also killing all the frame | |
311 | pointer based stores upon encountering a const function call. | |
312 | This field is set after reload for const function calls. Having | |
313 | this set is less severe than a wild read, it just means that all | |
314 | the frame related stores are killed rather than all the stores. */ | |
315 | bool frame_read; | |
316 | ||
317 | /* This field is only used for the processing of const functions. | |
318 | It is set if the insn may contain a stack pointer based store. */ | |
50f0f366 | 319 | bool stack_pointer_based; |
6fb5fa3c DB |
320 | |
321 | /* This is true if any of the sets within the store contains a | |
322 | cselib base. Such stores can only be deleted by the local | |
323 | algorithm. */ | |
324 | bool contains_cselib_groups; | |
325 | ||
326 | /* The insn. */ | |
327 | rtx insn; | |
328 | ||
329 | /* The list of mem sets or mem clobbers that are contained in this | |
330 | insn. If the insn is deletable, it contains only one mem set. | |
331 | But it could also contain clobbers. Insns that contain more than | |
332 | one mem set are not deletable, but each of those mems are here in | |
6ed3da00 | 333 | order to provide info to delete other insns. */ |
6fb5fa3c DB |
334 | store_info_t store_rec; |
335 | ||
336 | /* The linked list of mem uses in this insn. Only the reads from | |
337 | rtx bases are listed here. The reads to cselib bases are | |
338 | completely processed during the first scan and so are never | |
339 | created. */ | |
340 | read_info_t read_rec; | |
341 | ||
342 | /* The prev insn in the basic block. */ | |
343 | struct insn_info * prev_insn; | |
344 | ||
345 | /* The linked list of insns that are in consideration for removal in | |
346 | the forwards pass thru the basic block. This pointer may be | |
347 | trash as it is not cleared when a wild read occurs. The only | |
fa10beec | 348 | time it is guaranteed to be correct is when the traversal starts |
6fb5fa3c DB |
349 | at active_local_stores. */ |
350 | struct insn_info * next_local_store; | |
351 | }; | |
352 | ||
353 | typedef struct insn_info *insn_info_t; | |
354 | static alloc_pool insn_info_pool; | |
355 | ||
356 | /* The linked list of stores that are under consideration in this | |
357 | basic block. */ | |
358 | static insn_info_t active_local_stores; | |
359 | ||
360 | struct bb_info | |
361 | { | |
362 | ||
363 | /* Pointer to the insn info for the last insn in the block. These | |
364 | are linked so this is how all of the insns are reached. During | |
365 | scanning this is the current insn being scanned. */ | |
366 | insn_info_t last_insn; | |
367 | ||
368 | /* The info for the global dataflow problem. */ | |
369 | ||
370 | ||
371 | /* This is set if the transfer function should and in the wild_read | |
372 | bitmap before applying the kill and gen sets. That vector knocks | |
373 | out most of the bits in the bitmap and thus speeds up the | |
374 | operations. */ | |
375 | bool apply_wild_read; | |
376 | ||
02b47899 KZ |
377 | /* The following 4 bitvectors hold information about which positions |
378 | of which stores are live or dead. They are indexed by | |
379 | get_bitmap_index. */ | |
380 | ||
6fb5fa3c DB |
381 | /* The set of store positions that exist in this block before a wild read. */ |
382 | bitmap gen; | |
383 | ||
384 | /* The set of load positions that exist in this block above the | |
385 | same position of a store. */ | |
386 | bitmap kill; | |
387 | ||
388 | /* The set of stores that reach the top of the block without being | |
389 | killed by a read. | |
390 | ||
391 | Do not represent the in if it is all ones. Note that this is | |
392 | what the bitvector should logically be initialized to for a set | |
393 | intersection problem. However, like the kill set, this is too | |
394 | expensive. So initially, the in set will only be created for the | |
395 | exit block and any block that contains a wild read. */ | |
396 | bitmap in; | |
397 | ||
398 | /* The set of stores that reach the bottom of the block from it's | |
399 | successors. | |
400 | ||
401 | Do not represent the in if it is all ones. Note that this is | |
402 | what the bitvector should logically be initialized to for a set | |
403 | intersection problem. However, like the kill and in set, this is | |
404 | too expensive. So what is done is that the confluence operator | |
405 | just initializes the vector from one of the out sets of the | |
406 | successors of the block. */ | |
407 | bitmap out; | |
02b47899 KZ |
408 | |
409 | /* The following bitvector is indexed by the reg number. It | |
410 | contains the set of regs that are live at the current instruction | |
411 | being processed. While it contains info for all of the | |
412 | registers, only the pseudos are actually examined. It is used to | |
413 | assure that shift sequences that are inserted do not accidently | |
414 | clobber live hard regs. */ | |
415 | bitmap regs_live; | |
6fb5fa3c DB |
416 | }; |
417 | ||
418 | typedef struct bb_info *bb_info_t; | |
419 | static alloc_pool bb_info_pool; | |
420 | ||
421 | /* Table to hold all bb_infos. */ | |
422 | static bb_info_t *bb_table; | |
423 | ||
424 | /* There is a group_info for each rtx base that is used to reference | |
425 | memory. There are also not many of the rtx bases because they are | |
426 | very limited in scope. */ | |
427 | ||
428 | struct group_info | |
429 | { | |
430 | /* The actual base of the address. */ | |
431 | rtx rtx_base; | |
432 | ||
433 | /* The sequential id of the base. This allows us to have a | |
434 | canonical ordering of these that is not based on addresses. */ | |
435 | int id; | |
436 | ||
437 | /* A mem wrapped around the base pointer for the group in order to | |
438 | do read dependency. */ | |
439 | rtx base_mem; | |
440 | ||
441 | /* Canonized version of base_mem, most likely the same thing. */ | |
442 | rtx canon_base_mem; | |
443 | ||
444 | /* These two sets of two bitmaps are used to keep track of how many | |
6ed3da00 | 445 | stores are actually referencing that position from this base. We |
6fb5fa3c | 446 | only do this for rtx bases as this will be used to assign |
6ed3da00 | 447 | positions in the bitmaps for the global problem. Bit N is set in |
6fb5fa3c DB |
448 | store1 on the first store for offset N. Bit N is set in store2 |
449 | for the second store to offset N. This is all we need since we | |
450 | only care about offsets that have two or more stores for them. | |
451 | ||
452 | The "_n" suffix is for offsets less than 0 and the "_p" suffix is | |
453 | for 0 and greater offsets. | |
454 | ||
455 | There is one special case here, for stores into the stack frame, | |
456 | we will or store1 into store2 before deciding which stores look | |
457 | at globally. This is because stores to the stack frame that have | |
458 | no other reads before the end of the function can also be | |
459 | deleted. */ | |
460 | bitmap store1_n, store1_p, store2_n, store2_p; | |
461 | ||
6ed3da00 | 462 | /* The positions in this bitmap have the same assignments as the in, |
6fb5fa3c | 463 | out, gen and kill bitmaps. This bitmap is all zeros except for |
6ed3da00 | 464 | the positions that are occupied by stores for this group. */ |
6fb5fa3c DB |
465 | bitmap group_kill; |
466 | ||
467 | /* True if there are any positions that are to be processed | |
468 | globally. */ | |
469 | bool process_globally; | |
470 | ||
471 | /* True if the base of this group is either the frame_pointer or | |
472 | hard_frame_pointer. */ | |
473 | bool frame_related; | |
474 | ||
475 | /* The offset_map is used to map the offsets from this base into | |
6ed3da00 | 476 | positions in the global bitmaps. It is only created after all of |
6fb5fa3c DB |
477 | the all of stores have been scanned and we know which ones we |
478 | care about. */ | |
479 | int *offset_map_n, *offset_map_p; | |
480 | int offset_map_size_n, offset_map_size_p; | |
481 | }; | |
482 | typedef struct group_info *group_info_t; | |
5f754896 | 483 | typedef const struct group_info *const_group_info_t; |
6fb5fa3c DB |
484 | static alloc_pool rtx_group_info_pool; |
485 | ||
486 | /* Tables of group_info structures, hashed by base value. */ | |
487 | static htab_t rtx_group_table; | |
488 | ||
489 | /* Index into the rtx_group_vec. */ | |
490 | static int rtx_group_next_id; | |
491 | ||
492 | DEF_VEC_P(group_info_t); | |
493 | DEF_VEC_ALLOC_P(group_info_t,heap); | |
494 | ||
495 | static VEC(group_info_t,heap) *rtx_group_vec; | |
496 | ||
497 | ||
498 | /* This structure holds the set of changes that are being deferred | |
499 | when removing read operation. See replace_read. */ | |
500 | struct deferred_change | |
501 | { | |
502 | ||
503 | /* The mem that is being replaced. */ | |
504 | rtx *loc; | |
505 | ||
506 | /* The reg it is being replaced with. */ | |
507 | rtx reg; | |
508 | ||
509 | struct deferred_change *next; | |
510 | }; | |
511 | ||
512 | typedef struct deferred_change *deferred_change_t; | |
513 | static alloc_pool deferred_change_pool; | |
514 | ||
515 | static deferred_change_t deferred_change_list = NULL; | |
516 | ||
517 | /* This are used to hold the alias sets of spill variables. Since | |
518 | these are never aliased and there may be a lot of them, it makes | |
519 | sense to treat them specially. This bitvector is only allocated in | |
520 | calls from dse_record_singleton_alias_set which currently is only | |
521 | made during reload1. So when dse is called before reload this | |
522 | mechanism does nothing. */ | |
523 | ||
524 | static bitmap clear_alias_sets = NULL; | |
525 | ||
526 | /* The set of clear_alias_sets that have been disqualified because | |
527 | there are loads or stores using a different mode than the alias set | |
528 | was registered with. */ | |
529 | static bitmap disqualified_clear_alias_sets = NULL; | |
530 | ||
531 | /* The group that holds all of the clear_alias_sets. */ | |
532 | static group_info_t clear_alias_group; | |
533 | ||
534 | /* The modes of the clear_alias_sets. */ | |
535 | static htab_t clear_alias_mode_table; | |
536 | ||
537 | /* Hash table element to look up the mode for an alias set. */ | |
538 | struct clear_alias_mode_holder | |
539 | { | |
4862826d | 540 | alias_set_type alias_set; |
6fb5fa3c DB |
541 | enum machine_mode mode; |
542 | }; | |
543 | ||
544 | static alloc_pool clear_alias_mode_pool; | |
545 | ||
e3b5732b | 546 | /* This is true except if cfun->stdarg -- i.e. we cannot do |
9dd9bf80 | 547 | this for vararg functions because they play games with the frame. */ |
6fb5fa3c DB |
548 | static bool stores_off_frame_dead_at_return; |
549 | ||
550 | /* Counter for stats. */ | |
551 | static int globally_deleted; | |
552 | static int locally_deleted; | |
553 | static int spill_deleted; | |
554 | ||
555 | static bitmap all_blocks; | |
556 | ||
557 | /* The number of bits used in the global bitmaps. */ | |
558 | static unsigned int current_position; | |
559 | ||
560 | ||
561 | static bool gate_dse (void); | |
7d817ebc DE |
562 | static bool gate_dse1 (void); |
563 | static bool gate_dse2 (void); | |
6fb5fa3c DB |
564 | |
565 | \f | |
566 | /*---------------------------------------------------------------------------- | |
567 | Zeroth step. | |
568 | ||
569 | Initialization. | |
570 | ----------------------------------------------------------------------------*/ | |
571 | ||
572 | /* Hashtable callbacks for maintaining the "bases" field of | |
573 | store_group_info, given that the addresses are function invariants. */ | |
574 | ||
575 | static int | |
576 | clear_alias_mode_eq (const void *p1, const void *p2) | |
577 | { | |
578 | const struct clear_alias_mode_holder * h1 | |
579 | = (const struct clear_alias_mode_holder *) p1; | |
580 | const struct clear_alias_mode_holder * h2 | |
581 | = (const struct clear_alias_mode_holder *) p2; | |
582 | return h1->alias_set == h2->alias_set; | |
583 | } | |
584 | ||
585 | ||
586 | static hashval_t | |
587 | clear_alias_mode_hash (const void *p) | |
588 | { | |
589 | const struct clear_alias_mode_holder *holder | |
590 | = (const struct clear_alias_mode_holder *) p; | |
591 | return holder->alias_set; | |
592 | } | |
593 | ||
594 | ||
595 | /* Find the entry associated with ALIAS_SET. */ | |
596 | ||
597 | static struct clear_alias_mode_holder * | |
4862826d | 598 | clear_alias_set_lookup (alias_set_type alias_set) |
6fb5fa3c DB |
599 | { |
600 | struct clear_alias_mode_holder tmp_holder; | |
601 | void **slot; | |
602 | ||
603 | tmp_holder.alias_set = alias_set; | |
604 | slot = htab_find_slot (clear_alias_mode_table, &tmp_holder, NO_INSERT); | |
605 | gcc_assert (*slot); | |
606 | ||
f883e0a7 | 607 | return (struct clear_alias_mode_holder *) *slot; |
6fb5fa3c DB |
608 | } |
609 | ||
610 | ||
611 | /* Hashtable callbacks for maintaining the "bases" field of | |
612 | store_group_info, given that the addresses are function invariants. */ | |
613 | ||
614 | static int | |
615 | invariant_group_base_eq (const void *p1, const void *p2) | |
616 | { | |
5f754896 KG |
617 | const_group_info_t gi1 = (const_group_info_t) p1; |
618 | const_group_info_t gi2 = (const_group_info_t) p2; | |
6fb5fa3c DB |
619 | return rtx_equal_p (gi1->rtx_base, gi2->rtx_base); |
620 | } | |
621 | ||
622 | ||
623 | static hashval_t | |
624 | invariant_group_base_hash (const void *p) | |
625 | { | |
5f754896 | 626 | const_group_info_t gi = (const_group_info_t) p; |
6fb5fa3c DB |
627 | int do_not_record; |
628 | return hash_rtx (gi->rtx_base, Pmode, &do_not_record, NULL, false); | |
629 | } | |
630 | ||
631 | ||
632 | /* Get the GROUP for BASE. Add a new group if it is not there. */ | |
633 | ||
634 | static group_info_t | |
635 | get_group_info (rtx base) | |
636 | { | |
637 | struct group_info tmp_gi; | |
638 | group_info_t gi; | |
639 | void **slot; | |
640 | ||
641 | if (base) | |
642 | { | |
643 | /* Find the store_base_info structure for BASE, creating a new one | |
644 | if necessary. */ | |
645 | tmp_gi.rtx_base = base; | |
646 | slot = htab_find_slot (rtx_group_table, &tmp_gi, INSERT); | |
647 | gi = (group_info_t) *slot; | |
648 | } | |
649 | else | |
650 | { | |
651 | if (!clear_alias_group) | |
652 | { | |
f883e0a7 KG |
653 | clear_alias_group = gi = |
654 | (group_info_t) pool_alloc (rtx_group_info_pool); | |
6fb5fa3c DB |
655 | memset (gi, 0, sizeof (struct group_info)); |
656 | gi->id = rtx_group_next_id++; | |
657 | gi->store1_n = BITMAP_ALLOC (NULL); | |
658 | gi->store1_p = BITMAP_ALLOC (NULL); | |
659 | gi->store2_n = BITMAP_ALLOC (NULL); | |
660 | gi->store2_p = BITMAP_ALLOC (NULL); | |
661 | gi->group_kill = BITMAP_ALLOC (NULL); | |
662 | gi->process_globally = false; | |
663 | gi->offset_map_size_n = 0; | |
664 | gi->offset_map_size_p = 0; | |
665 | gi->offset_map_n = NULL; | |
666 | gi->offset_map_p = NULL; | |
667 | VEC_safe_push (group_info_t, heap, rtx_group_vec, gi); | |
668 | } | |
669 | return clear_alias_group; | |
670 | } | |
671 | ||
672 | if (gi == NULL) | |
673 | { | |
f883e0a7 | 674 | *slot = gi = (group_info_t) pool_alloc (rtx_group_info_pool); |
6fb5fa3c DB |
675 | gi->rtx_base = base; |
676 | gi->id = rtx_group_next_id++; | |
677 | gi->base_mem = gen_rtx_MEM (QImode, base); | |
678 | gi->canon_base_mem = canon_rtx (gi->base_mem); | |
679 | gi->store1_n = BITMAP_ALLOC (NULL); | |
680 | gi->store1_p = BITMAP_ALLOC (NULL); | |
681 | gi->store2_n = BITMAP_ALLOC (NULL); | |
682 | gi->store2_p = BITMAP_ALLOC (NULL); | |
683 | gi->group_kill = BITMAP_ALLOC (NULL); | |
684 | gi->process_globally = false; | |
685 | gi->frame_related = | |
686 | (base == frame_pointer_rtx) || (base == hard_frame_pointer_rtx); | |
687 | gi->offset_map_size_n = 0; | |
688 | gi->offset_map_size_p = 0; | |
689 | gi->offset_map_n = NULL; | |
690 | gi->offset_map_p = NULL; | |
691 | VEC_safe_push (group_info_t, heap, rtx_group_vec, gi); | |
692 | } | |
693 | ||
694 | return gi; | |
695 | } | |
696 | ||
697 | ||
698 | /* Initialization of data structures. */ | |
699 | ||
700 | static void | |
701 | dse_step0 (void) | |
702 | { | |
703 | locally_deleted = 0; | |
704 | globally_deleted = 0; | |
705 | spill_deleted = 0; | |
706 | ||
707 | scratch = BITMAP_ALLOC (NULL); | |
708 | ||
709 | rtx_store_info_pool | |
710 | = create_alloc_pool ("rtx_store_info_pool", | |
711 | sizeof (struct store_info), 100); | |
712 | read_info_pool | |
713 | = create_alloc_pool ("read_info_pool", | |
714 | sizeof (struct read_info), 100); | |
715 | insn_info_pool | |
716 | = create_alloc_pool ("insn_info_pool", | |
717 | sizeof (struct insn_info), 100); | |
718 | bb_info_pool | |
719 | = create_alloc_pool ("bb_info_pool", | |
720 | sizeof (struct bb_info), 100); | |
721 | rtx_group_info_pool | |
722 | = create_alloc_pool ("rtx_group_info_pool", | |
723 | sizeof (struct group_info), 100); | |
724 | deferred_change_pool | |
725 | = create_alloc_pool ("deferred_change_pool", | |
726 | sizeof (struct deferred_change), 10); | |
727 | ||
728 | rtx_group_table = htab_create (11, invariant_group_base_hash, | |
729 | invariant_group_base_eq, NULL); | |
730 | ||
731 | bb_table = XCNEWVEC (bb_info_t, last_basic_block); | |
732 | rtx_group_next_id = 0; | |
733 | ||
e3b5732b | 734 | stores_off_frame_dead_at_return = !cfun->stdarg; |
6fb5fa3c DB |
735 | |
736 | init_alias_analysis (); | |
737 | ||
738 | if (clear_alias_sets) | |
739 | clear_alias_group = get_group_info (NULL); | |
740 | else | |
741 | clear_alias_group = NULL; | |
742 | } | |
743 | ||
744 | ||
745 | \f | |
746 | /*---------------------------------------------------------------------------- | |
747 | First step. | |
748 | ||
749 | Scan all of the insns. Any random ordering of the blocks is fine. | |
0d52bcc1 | 750 | Each block is scanned in forward order to accommodate cselib which |
6fb5fa3c DB |
751 | is used to remove stores with non-constant bases. |
752 | ----------------------------------------------------------------------------*/ | |
753 | ||
754 | /* Delete all of the store_info recs from INSN_INFO. */ | |
755 | ||
756 | static void | |
757 | free_store_info (insn_info_t insn_info) | |
758 | { | |
759 | store_info_t store_info = insn_info->store_rec; | |
760 | while (store_info) | |
761 | { | |
762 | store_info_t next = store_info->next; | |
763 | if (store_info->cse_base) | |
764 | pool_free (cse_store_info_pool, store_info); | |
765 | else | |
766 | pool_free (rtx_store_info_pool, store_info); | |
767 | store_info = next; | |
768 | } | |
769 | ||
770 | insn_info->cannot_delete = true; | |
771 | insn_info->contains_cselib_groups = false; | |
772 | insn_info->store_rec = NULL; | |
773 | } | |
774 | ||
775 | ||
776 | struct insn_size { | |
777 | int size; | |
778 | rtx insn; | |
779 | }; | |
780 | ||
781 | ||
782 | /* Add an insn to do the add inside a x if it is a | |
783 | PRE/POST-INC/DEC/MODIFY. D is an structure containing the insn and | |
784 | the size of the mode of the MEM that this is inside of. */ | |
785 | ||
786 | static int | |
787 | replace_inc_dec (rtx *r, void *d) | |
788 | { | |
789 | rtx x = *r; | |
790 | struct insn_size *data = (struct insn_size *)d; | |
791 | switch (GET_CODE (x)) | |
792 | { | |
793 | case PRE_INC: | |
794 | case POST_INC: | |
795 | { | |
796 | rtx r1 = XEXP (x, 0); | |
797 | rtx c = gen_int_mode (Pmode, data->size); | |
22129589 AS |
798 | emit_insn_before (gen_rtx_SET (Pmode, r1, |
799 | gen_rtx_PLUS (Pmode, r1, c)), | |
800 | data->insn); | |
6fb5fa3c DB |
801 | return -1; |
802 | } | |
803 | ||
804 | case PRE_DEC: | |
805 | case POST_DEC: | |
806 | { | |
807 | rtx r1 = XEXP (x, 0); | |
808 | rtx c = gen_int_mode (Pmode, -data->size); | |
22129589 AS |
809 | emit_insn_before (gen_rtx_SET (Pmode, r1, |
810 | gen_rtx_PLUS (Pmode, r1, c)), | |
811 | data->insn); | |
6fb5fa3c DB |
812 | return -1; |
813 | } | |
814 | ||
815 | case PRE_MODIFY: | |
816 | case POST_MODIFY: | |
817 | { | |
0d52bcc1 | 818 | /* We can reuse the add because we are about to delete the |
6fb5fa3c DB |
819 | insn that contained it. */ |
820 | rtx add = XEXP (x, 0); | |
821 | rtx r1 = XEXP (add, 0); | |
22129589 | 822 | emit_insn_before (gen_rtx_SET (Pmode, r1, add), data->insn); |
6fb5fa3c DB |
823 | return -1; |
824 | } | |
825 | ||
826 | default: | |
827 | return 0; | |
828 | } | |
829 | } | |
830 | ||
831 | ||
832 | /* If X is a MEM, check the address to see if it is PRE/POST-INC/DEC/MODIFY | |
833 | and generate an add to replace that. */ | |
834 | ||
835 | static int | |
836 | replace_inc_dec_mem (rtx *r, void *d) | |
837 | { | |
838 | rtx x = *r; | |
22129589 | 839 | if (x != NULL_RTX && MEM_P (x)) |
6fb5fa3c DB |
840 | { |
841 | struct insn_size data; | |
842 | ||
843 | data.size = GET_MODE_SIZE (GET_MODE (x)); | |
22129589 | 844 | data.insn = (rtx) d; |
6fb5fa3c DB |
845 | |
846 | for_each_rtx (&XEXP (x, 0), replace_inc_dec, &data); | |
847 | ||
848 | return -1; | |
849 | } | |
850 | return 0; | |
851 | } | |
852 | ||
853 | /* Before we delete INSN, make sure that the auto inc/dec, if it is | |
854 | there, is split into a separate insn. */ | |
855 | ||
856 | static void | |
857 | check_for_inc_dec (rtx insn) | |
858 | { | |
859 | rtx note = find_reg_note (insn, REG_INC, NULL_RTX); | |
860 | if (note) | |
861 | for_each_rtx (&insn, replace_inc_dec_mem, insn); | |
862 | } | |
863 | ||
864 | ||
865 | /* Delete the insn and free all of the fields inside INSN_INFO. */ | |
866 | ||
867 | static void | |
868 | delete_dead_store_insn (insn_info_t insn_info) | |
869 | { | |
870 | read_info_t read_info; | |
871 | ||
872 | if (!dbg_cnt (dse)) | |
873 | return; | |
874 | ||
875 | check_for_inc_dec (insn_info->insn); | |
876 | if (dump_file) | |
877 | { | |
878 | fprintf (dump_file, "Locally deleting insn %d ", | |
879 | INSN_UID (insn_info->insn)); | |
880 | if (insn_info->store_rec->alias_set) | |
881 | fprintf (dump_file, "alias set %d\n", | |
4862826d | 882 | (int) insn_info->store_rec->alias_set); |
6fb5fa3c DB |
883 | else |
884 | fprintf (dump_file, "\n"); | |
885 | } | |
886 | ||
887 | free_store_info (insn_info); | |
888 | read_info = insn_info->read_rec; | |
889 | ||
890 | while (read_info) | |
891 | { | |
892 | read_info_t next = read_info->next; | |
893 | pool_free (read_info_pool, read_info); | |
894 | read_info = next; | |
895 | } | |
896 | insn_info->read_rec = NULL; | |
897 | ||
898 | delete_insn (insn_info->insn); | |
899 | locally_deleted++; | |
900 | insn_info->insn = NULL; | |
901 | ||
902 | insn_info->wild_read = false; | |
903 | } | |
904 | ||
905 | ||
906 | /* Set the store* bitmaps offset_map_size* fields in GROUP based on | |
907 | OFFSET and WIDTH. */ | |
908 | ||
909 | static void | |
910 | set_usage_bits (group_info_t group, HOST_WIDE_INT offset, HOST_WIDE_INT width) | |
911 | { | |
912 | HOST_WIDE_INT i; | |
913 | ||
914 | if ((offset > -MAX_OFFSET) && (offset < MAX_OFFSET)) | |
915 | for (i=offset; i<offset+width; i++) | |
916 | { | |
917 | bitmap store1; | |
918 | bitmap store2; | |
919 | int ai; | |
920 | if (i < 0) | |
921 | { | |
922 | store1 = group->store1_n; | |
923 | store2 = group->store2_n; | |
924 | ai = -i; | |
925 | } | |
926 | else | |
927 | { | |
928 | store1 = group->store1_p; | |
929 | store2 = group->store2_p; | |
930 | ai = i; | |
931 | } | |
932 | ||
933 | if (bitmap_bit_p (store1, ai)) | |
934 | bitmap_set_bit (store2, ai); | |
935 | else | |
936 | { | |
937 | bitmap_set_bit (store1, ai); | |
938 | if (i < 0) | |
939 | { | |
940 | if (group->offset_map_size_n < ai) | |
941 | group->offset_map_size_n = ai; | |
942 | } | |
943 | else | |
944 | { | |
945 | if (group->offset_map_size_p < ai) | |
946 | group->offset_map_size_p = ai; | |
947 | } | |
948 | } | |
949 | } | |
950 | } | |
951 | ||
952 | ||
953 | /* Set the BB_INFO so that the last insn is marked as a wild read. */ | |
954 | ||
955 | static void | |
956 | add_wild_read (bb_info_t bb_info) | |
957 | { | |
958 | insn_info_t insn_info = bb_info->last_insn; | |
959 | read_info_t *ptr = &insn_info->read_rec; | |
960 | ||
961 | while (*ptr) | |
962 | { | |
963 | read_info_t next = (*ptr)->next; | |
4862826d | 964 | if ((*ptr)->alias_set == 0) |
6fb5fa3c DB |
965 | { |
966 | pool_free (read_info_pool, *ptr); | |
967 | *ptr = next; | |
968 | } | |
969 | else | |
970 | ptr = &(*ptr)->next; | |
971 | } | |
972 | insn_info->wild_read = true; | |
973 | active_local_stores = NULL; | |
974 | } | |
975 | ||
976 | ||
50f0f366 EB |
977 | /* Return true if X is a constant or one of the registers that behave |
978 | as a constant over the life of a function. This is equivalent to | |
979 | !rtx_varies_p for memory addresses. */ | |
6fb5fa3c DB |
980 | |
981 | static bool | |
982 | const_or_frame_p (rtx x) | |
983 | { | |
984 | switch (GET_CODE (x)) | |
985 | { | |
986 | case MEM: | |
987 | return MEM_READONLY_P (x); | |
988 | ||
989 | case CONST: | |
990 | case CONST_INT: | |
991 | case CONST_DOUBLE: | |
992 | case CONST_VECTOR: | |
993 | case SYMBOL_REF: | |
994 | case LABEL_REF: | |
995 | return true; | |
996 | ||
997 | case REG: | |
998 | /* Note that we have to test for the actual rtx used for the frame | |
999 | and arg pointers and not just the register number in case we have | |
1000 | eliminated the frame and/or arg pointer and are using it | |
1001 | for pseudos. */ | |
1002 | if (x == frame_pointer_rtx || x == hard_frame_pointer_rtx | |
1003 | /* The arg pointer varies if it is not a fixed register. */ | |
1004 | || (x == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]) | |
1005 | || x == pic_offset_table_rtx) | |
1006 | return true; | |
1007 | return false; | |
1008 | ||
1009 | default: | |
1010 | return false; | |
1011 | } | |
1012 | } | |
1013 | ||
1014 | /* Take all reasonable action to put the address of MEM into the form | |
1015 | that we can do analysis on. | |
1016 | ||
1017 | The gold standard is to get the address into the form: address + | |
1018 | OFFSET where address is something that rtx_varies_p considers a | |
1019 | constant. When we can get the address in this form, we can do | |
1020 | global analysis on it. Note that for constant bases, address is | |
1021 | not actually returned, only the group_id. The address can be | |
1022 | obtained from that. | |
1023 | ||
1024 | If that fails, we try cselib to get a value we can at least use | |
1025 | locally. If that fails we return false. | |
1026 | ||
1027 | The GROUP_ID is set to -1 for cselib bases and the index of the | |
1028 | group for non_varying bases. | |
1029 | ||
1030 | FOR_READ is true if this is a mem read and false if not. */ | |
1031 | ||
1032 | static bool | |
1033 | canon_address (rtx mem, | |
4862826d | 1034 | alias_set_type *alias_set_out, |
6fb5fa3c DB |
1035 | int *group_id, |
1036 | HOST_WIDE_INT *offset, | |
1037 | cselib_val **base) | |
1038 | { | |
1039 | rtx mem_address = XEXP (mem, 0); | |
1040 | rtx expanded_address, address; | |
1041 | /* Make sure that cselib is has initialized all of the operands of | |
1042 | the address before asking it to do the subst. */ | |
1043 | ||
1044 | if (clear_alias_sets) | |
1045 | { | |
1046 | /* If this is a spill, do not do any further processing. */ | |
4862826d | 1047 | alias_set_type alias_set = MEM_ALIAS_SET (mem); |
6fb5fa3c | 1048 | if (dump_file) |
4862826d | 1049 | fprintf (dump_file, "found alias set %d\n", (int) alias_set); |
6fb5fa3c DB |
1050 | if (bitmap_bit_p (clear_alias_sets, alias_set)) |
1051 | { | |
1052 | struct clear_alias_mode_holder *entry | |
1053 | = clear_alias_set_lookup (alias_set); | |
1054 | ||
1055 | /* If the modes do not match, we cannot process this set. */ | |
1056 | if (entry->mode != GET_MODE (mem)) | |
1057 | { | |
1058 | if (dump_file) | |
1059 | fprintf (dump_file, | |
1060 | "disqualifying alias set %d, (%s) != (%s)\n", | |
4862826d | 1061 | (int) alias_set, GET_MODE_NAME (entry->mode), |
6fb5fa3c DB |
1062 | GET_MODE_NAME (GET_MODE (mem))); |
1063 | ||
1064 | bitmap_set_bit (disqualified_clear_alias_sets, alias_set); | |
1065 | return false; | |
1066 | } | |
1067 | ||
1068 | *alias_set_out = alias_set; | |
1069 | *group_id = clear_alias_group->id; | |
1070 | return true; | |
1071 | } | |
1072 | } | |
1073 | ||
1074 | *alias_set_out = 0; | |
1075 | ||
1076 | cselib_lookup (mem_address, Pmode, 1); | |
1077 | ||
1078 | if (dump_file) | |
1079 | { | |
1080 | fprintf (dump_file, " mem: "); | |
1081 | print_inline_rtx (dump_file, mem_address, 0); | |
1082 | fprintf (dump_file, "\n"); | |
1083 | } | |
1084 | ||
1085 | /* Use cselib to replace all of the reg references with the full | |
1086 | expression. This will take care of the case where we have | |
1087 | ||
1088 | r_x = base + offset; | |
1089 | val = *r_x; | |
1090 | ||
1091 | by making it into | |
1092 | ||
1093 | val = *(base + offset); | |
1094 | */ | |
1095 | ||
1096 | expanded_address = cselib_expand_value_rtx (mem_address, scratch, 5); | |
1097 | ||
1098 | /* If this fails, just go with the mem_address. */ | |
1099 | if (!expanded_address) | |
1100 | expanded_address = mem_address; | |
1101 | ||
1102 | /* Split the address into canonical BASE + OFFSET terms. */ | |
1103 | address = canon_rtx (expanded_address); | |
1104 | ||
1105 | *offset = 0; | |
1106 | ||
1107 | if (dump_file) | |
1108 | { | |
1109 | fprintf (dump_file, "\n after cselib_expand address: "); | |
1110 | print_inline_rtx (dump_file, expanded_address, 0); | |
1111 | fprintf (dump_file, "\n"); | |
1112 | ||
1113 | fprintf (dump_file, "\n after canon_rtx address: "); | |
1114 | print_inline_rtx (dump_file, address, 0); | |
1115 | fprintf (dump_file, "\n"); | |
1116 | } | |
1117 | ||
1118 | if (GET_CODE (address) == CONST) | |
1119 | address = XEXP (address, 0); | |
1120 | ||
1121 | if (GET_CODE (address) == PLUS && GET_CODE (XEXP (address, 1)) == CONST_INT) | |
1122 | { | |
1123 | *offset = INTVAL (XEXP (address, 1)); | |
1124 | address = XEXP (address, 0); | |
1125 | } | |
1126 | ||
1127 | if (const_or_frame_p (address)) | |
1128 | { | |
1129 | group_info_t group = get_group_info (address); | |
1130 | ||
1131 | if (dump_file) | |
1132 | fprintf (dump_file, " gid=%d offset=%d \n", group->id, (int)*offset); | |
1133 | *base = NULL; | |
1134 | *group_id = group->id; | |
1135 | } | |
1136 | else | |
1137 | { | |
1138 | *base = cselib_lookup (address, Pmode, true); | |
1139 | *group_id = -1; | |
1140 | ||
1141 | if (*base == NULL) | |
1142 | { | |
1143 | if (dump_file) | |
1144 | fprintf (dump_file, " no cselib val - should be a wild read.\n"); | |
1145 | return false; | |
1146 | } | |
1147 | if (dump_file) | |
1148 | fprintf (dump_file, " varying cselib base=%d offset = %d\n", | |
1149 | (*base)->value, (int)*offset); | |
1150 | } | |
1151 | return true; | |
1152 | } | |
1153 | ||
1154 | ||
1155 | /* Clear the rhs field from the active_local_stores array. */ | |
1156 | ||
1157 | static void | |
1158 | clear_rhs_from_active_local_stores (void) | |
1159 | { | |
1160 | insn_info_t ptr = active_local_stores; | |
1161 | ||
1162 | while (ptr) | |
1163 | { | |
1164 | store_info_t store_info = ptr->store_rec; | |
1165 | /* Skip the clobbers. */ | |
1166 | while (!store_info->is_set) | |
1167 | store_info = store_info->next; | |
1168 | ||
1169 | store_info->rhs = NULL; | |
1170 | ||
1171 | ptr = ptr->next_local_store; | |
1172 | } | |
1173 | } | |
1174 | ||
1175 | ||
1176 | /* BODY is an instruction pattern that belongs to INSN. Return 1 if | |
1177 | there is a candidate store, after adding it to the appropriate | |
1178 | local store group if so. */ | |
1179 | ||
1180 | static int | |
1181 | record_store (rtx body, bb_info_t bb_info) | |
1182 | { | |
1183 | rtx mem; | |
1184 | HOST_WIDE_INT offset = 0; | |
1185 | HOST_WIDE_INT width = 0; | |
4862826d | 1186 | alias_set_type spill_alias_set; |
6fb5fa3c DB |
1187 | insn_info_t insn_info = bb_info->last_insn; |
1188 | store_info_t store_info = NULL; | |
1189 | int group_id; | |
1190 | cselib_val *base = NULL; | |
1191 | insn_info_t ptr, last; | |
1192 | bool store_is_unused; | |
1193 | ||
1194 | if (GET_CODE (body) != SET && GET_CODE (body) != CLOBBER) | |
1195 | return 0; | |
1196 | ||
1197 | /* If this is not used, then this cannot be used to keep the insn | |
1198 | from being deleted. On the other hand, it does provide something | |
1199 | that can be used to prove that another store is dead. */ | |
1200 | store_is_unused | |
1201 | = (find_reg_note (insn_info->insn, REG_UNUSED, body) != NULL); | |
1202 | ||
1203 | /* Check whether that value is a suitable memory location. */ | |
1204 | mem = SET_DEST (body); | |
1205 | if (!MEM_P (mem)) | |
1206 | { | |
1207 | /* If the set or clobber is unused, then it does not effect our | |
1208 | ability to get rid of the entire insn. */ | |
1209 | if (!store_is_unused) | |
1210 | insn_info->cannot_delete = true; | |
1211 | return 0; | |
1212 | } | |
1213 | ||
1214 | /* At this point we know mem is a mem. */ | |
1215 | if (GET_MODE (mem) == BLKmode) | |
1216 | { | |
1217 | if (GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
1218 | { | |
1219 | if (dump_file) | |
1220 | fprintf (dump_file, " adding wild read for (clobber (mem:BLK (scratch))\n"); | |
1221 | add_wild_read (bb_info); | |
1222 | insn_info->cannot_delete = true; | |
1223 | } | |
1224 | else if (!store_is_unused) | |
1225 | { | |
1226 | /* If the set or clobber is unused, then it does not effect our | |
1227 | ability to get rid of the entire insn. */ | |
1228 | insn_info->cannot_delete = true; | |
1229 | clear_rhs_from_active_local_stores (); | |
1230 | } | |
1231 | return 0; | |
1232 | } | |
1233 | ||
1234 | /* We can still process a volatile mem, we just cannot delete it. */ | |
1235 | if (MEM_VOLATILE_P (mem)) | |
1236 | insn_info->cannot_delete = true; | |
1237 | ||
1238 | if (!canon_address (mem, &spill_alias_set, &group_id, &offset, &base)) | |
1239 | { | |
1240 | clear_rhs_from_active_local_stores (); | |
1241 | return 0; | |
1242 | } | |
1243 | ||
1244 | width = GET_MODE_SIZE (GET_MODE (mem)); | |
1245 | ||
1246 | if (spill_alias_set) | |
1247 | { | |
1248 | bitmap store1 = clear_alias_group->store1_p; | |
1249 | bitmap store2 = clear_alias_group->store2_p; | |
1250 | ||
1251 | if (bitmap_bit_p (store1, spill_alias_set)) | |
1252 | bitmap_set_bit (store2, spill_alias_set); | |
1253 | else | |
1254 | bitmap_set_bit (store1, spill_alias_set); | |
1255 | ||
1256 | if (clear_alias_group->offset_map_size_p < spill_alias_set) | |
1257 | clear_alias_group->offset_map_size_p = spill_alias_set; | |
1258 | ||
f883e0a7 | 1259 | store_info = (store_info_t) pool_alloc (rtx_store_info_pool); |
6fb5fa3c DB |
1260 | |
1261 | if (dump_file) | |
1262 | fprintf (dump_file, " processing spill store %d(%s)\n", | |
4862826d | 1263 | (int) spill_alias_set, GET_MODE_NAME (GET_MODE (mem))); |
6fb5fa3c DB |
1264 | } |
1265 | else if (group_id >= 0) | |
1266 | { | |
1267 | /* In the restrictive case where the base is a constant or the | |
1268 | frame pointer we can do global analysis. */ | |
1269 | ||
1270 | group_info_t group | |
1271 | = VEC_index (group_info_t, rtx_group_vec, group_id); | |
1272 | ||
f883e0a7 | 1273 | store_info = (store_info_t) pool_alloc (rtx_store_info_pool); |
6fb5fa3c DB |
1274 | set_usage_bits (group, offset, width); |
1275 | ||
1276 | if (dump_file) | |
1277 | fprintf (dump_file, " processing const base store gid=%d[%d..%d)\n", | |
1278 | group_id, (int)offset, (int)(offset+width)); | |
1279 | } | |
1280 | else | |
1281 | { | |
50f0f366 EB |
1282 | rtx base_term = find_base_term (XEXP (mem, 0)); |
1283 | if (!base_term | |
1284 | || (GET_CODE (base_term) == ADDRESS | |
1285 | && GET_MODE (base_term) == Pmode | |
1286 | && XEXP (base_term, 0) == stack_pointer_rtx)) | |
1287 | insn_info->stack_pointer_based = true; | |
6fb5fa3c | 1288 | insn_info->contains_cselib_groups = true; |
50f0f366 | 1289 | |
f883e0a7 | 1290 | store_info = (store_info_t) pool_alloc (cse_store_info_pool); |
6fb5fa3c DB |
1291 | group_id = -1; |
1292 | ||
1293 | if (dump_file) | |
1294 | fprintf (dump_file, " processing cselib store [%d..%d)\n", | |
1295 | (int)offset, (int)(offset+width)); | |
1296 | } | |
1297 | ||
1298 | /* Check to see if this stores causes some other stores to be | |
1299 | dead. */ | |
1300 | ptr = active_local_stores; | |
1301 | last = NULL; | |
1302 | ||
1303 | while (ptr) | |
1304 | { | |
1305 | insn_info_t next = ptr->next_local_store; | |
1306 | store_info_t s_info = ptr->store_rec; | |
60564289 | 1307 | bool del = true; |
6fb5fa3c DB |
1308 | |
1309 | /* Skip the clobbers. We delete the active insn if this insn | |
6ed3da00 | 1310 | shadows the set. To have been put on the active list, it |
6fb5fa3c DB |
1311 | has exactly on set. */ |
1312 | while (!s_info->is_set) | |
1313 | s_info = s_info->next; | |
1314 | ||
1315 | if (s_info->alias_set != spill_alias_set) | |
60564289 | 1316 | del = false; |
6fb5fa3c DB |
1317 | else if (s_info->alias_set) |
1318 | { | |
1319 | struct clear_alias_mode_holder *entry | |
1320 | = clear_alias_set_lookup (s_info->alias_set); | |
1321 | /* Generally, spills cannot be processed if and of the | |
1322 | references to the slot have a different mode. But if | |
1323 | we are in the same block and mode is exactly the same | |
1324 | between this store and one before in the same block, | |
1325 | we can still delete it. */ | |
1326 | if ((GET_MODE (mem) == GET_MODE (s_info->mem)) | |
1327 | && (GET_MODE (mem) == entry->mode)) | |
1328 | { | |
60564289 | 1329 | del = true; |
4fe663b0 | 1330 | s_info->positions_needed = (unsigned HOST_WIDE_INT) 0; |
6fb5fa3c DB |
1331 | } |
1332 | if (dump_file) | |
1333 | fprintf (dump_file, " trying spill store in insn=%d alias_set=%d\n", | |
4862826d | 1334 | INSN_UID (ptr->insn), (int) s_info->alias_set); |
6fb5fa3c DB |
1335 | } |
1336 | else if ((s_info->group_id == group_id) | |
1337 | && (s_info->cse_base == base)) | |
1338 | { | |
1339 | HOST_WIDE_INT i; | |
1340 | if (dump_file) | |
1341 | fprintf (dump_file, " trying store in insn=%d gid=%d[%d..%d)\n", | |
1342 | INSN_UID (ptr->insn), s_info->group_id, | |
1343 | (int)s_info->begin, (int)s_info->end); | |
1344 | for (i = offset; i < offset+width; i++) | |
1345 | if (i >= s_info->begin && i < s_info->end) | |
4fe663b0 L |
1346 | s_info->positions_needed |
1347 | &= ~(((unsigned HOST_WIDE_INT) 1) << (i - s_info->begin)); | |
6fb5fa3c DB |
1348 | } |
1349 | else if (s_info->rhs) | |
1350 | /* Need to see if it is possible for this store to overwrite | |
1351 | the value of store_info. If it is, set the rhs to NULL to | |
1352 | keep it from being used to remove a load. */ | |
1353 | { | |
1354 | if (canon_true_dependence (s_info->mem, | |
1355 | GET_MODE (s_info->mem), | |
1356 | s_info->mem_addr, | |
1357 | mem, rtx_varies_p)) | |
1358 | s_info->rhs = NULL; | |
1359 | } | |
1360 | ||
1361 | /* An insn can be deleted if every position of every one of | |
1362 | its s_infos is zero. */ | |
4fe663b0 | 1363 | if (s_info->positions_needed != (unsigned HOST_WIDE_INT) 0) |
60564289 | 1364 | del = false; |
6fb5fa3c | 1365 | |
60564289 | 1366 | if (del) |
6fb5fa3c DB |
1367 | { |
1368 | insn_info_t insn_to_delete = ptr; | |
1369 | ||
1370 | if (last) | |
1371 | last->next_local_store = ptr->next_local_store; | |
1372 | else | |
1373 | active_local_stores = ptr->next_local_store; | |
1374 | ||
1375 | delete_dead_store_insn (insn_to_delete); | |
1376 | } | |
1377 | else | |
1378 | last = ptr; | |
1379 | ||
1380 | ptr = next; | |
1381 | } | |
1382 | ||
9d6facc7 | 1383 | gcc_assert ((unsigned) width <= HOST_BITS_PER_WIDE_INT); |
6fb5fa3c DB |
1384 | |
1385 | /* Finish filling in the store_info. */ | |
1386 | store_info->next = insn_info->store_rec; | |
1387 | insn_info->store_rec = store_info; | |
1388 | store_info->mem = canon_rtx (mem); | |
1389 | store_info->alias_set = spill_alias_set; | |
1390 | store_info->mem_addr = get_addr (XEXP (mem, 0)); | |
1391 | store_info->cse_base = base; | |
4fe663b0 | 1392 | store_info->positions_needed = lowpart_bitmask (width); |
6fb5fa3c DB |
1393 | store_info->group_id = group_id; |
1394 | store_info->begin = offset; | |
1395 | store_info->end = offset + width; | |
1396 | store_info->is_set = GET_CODE (body) == SET; | |
1397 | ||
1398 | if (store_info->is_set | |
1399 | /* No place to keep the value after ra. */ | |
1400 | && !reload_completed | |
18b526e8 RS |
1401 | && (REG_P (SET_SRC (body)) |
1402 | || GET_CODE (SET_SRC (body)) == SUBREG | |
1403 | || CONSTANT_P (SET_SRC (body))) | |
6fb5fa3c DB |
1404 | /* Sometimes the store and reload is used for truncation and |
1405 | rounding. */ | |
1406 | && !(FLOAT_MODE_P (GET_MODE (mem)) && (flag_float_store))) | |
1407 | store_info->rhs = SET_SRC (body); | |
1408 | else | |
1409 | store_info->rhs = NULL; | |
1410 | ||
1411 | /* If this is a clobber, we return 0. We will only be able to | |
1412 | delete this insn if there is only one store USED store, but we | |
1413 | can use the clobber to delete other stores earlier. */ | |
1414 | return store_info->is_set ? 1 : 0; | |
1415 | } | |
1416 | ||
1417 | ||
1418 | static void | |
1419 | dump_insn_info (const char * start, insn_info_t insn_info) | |
1420 | { | |
1421 | fprintf (dump_file, "%s insn=%d %s\n", start, | |
1422 | INSN_UID (insn_info->insn), | |
1423 | insn_info->store_rec ? "has store" : "naked"); | |
1424 | } | |
1425 | ||
1426 | ||
8660aaae EC |
1427 | /* If the modes are different and the value's source and target do not |
1428 | line up, we need to extract the value from lower part of the rhs of | |
1429 | the store, shift it, and then put it into a form that can be shoved | |
1430 | into the read_insn. This function generates a right SHIFT of a | |
1431 | value that is at least ACCESS_SIZE bytes wide of READ_MODE. The | |
1432 | shift sequence is returned or NULL if we failed to find a | |
1433 | shift. */ | |
1434 | ||
1435 | static rtx | |
18b526e8 | 1436 | find_shift_sequence (int access_size, |
8660aaae EC |
1437 | store_info_t store_info, |
1438 | read_info_t read_info, | |
f40751dd JH |
1439 | int shift, |
1440 | bool speed) | |
8660aaae EC |
1441 | { |
1442 | enum machine_mode store_mode = GET_MODE (store_info->mem); | |
1443 | enum machine_mode read_mode = GET_MODE (read_info->mem); | |
18b526e8 RS |
1444 | enum machine_mode new_mode; |
1445 | rtx read_reg = NULL; | |
8660aaae EC |
1446 | |
1447 | /* Some machines like the x86 have shift insns for each size of | |
1448 | operand. Other machines like the ppc or the ia-64 may only have | |
1449 | shift insns that shift values within 32 or 64 bit registers. | |
1450 | This loop tries to find the smallest shift insn that will right | |
1451 | justify the value we want to read but is available in one insn on | |
1452 | the machine. */ | |
1453 | ||
18b526e8 RS |
1454 | for (new_mode = smallest_mode_for_size (access_size * BITS_PER_UNIT, |
1455 | MODE_INT); | |
1456 | GET_MODE_BITSIZE (new_mode) <= BITS_PER_WORD; | |
1457 | new_mode = GET_MODE_WIDER_MODE (new_mode)) | |
8660aaae | 1458 | { |
18b526e8 | 1459 | rtx target, new_reg, shift_seq, insn, new_lhs; |
d898d29b | 1460 | int cost; |
348eea5f | 1461 | |
72a2609f JJ |
1462 | /* If a constant was stored into memory, try to simplify it here, |
1463 | otherwise the cost of the shift might preclude this optimization | |
1464 | e.g. at -Os, even when no actual shift will be needed. */ | |
1465 | if (CONSTANT_P (store_info->rhs)) | |
1466 | { | |
1467 | unsigned int byte = subreg_lowpart_offset (new_mode, store_mode); | |
1468 | rtx ret = simplify_subreg (new_mode, store_info->rhs, store_mode, | |
1469 | byte); | |
1470 | if (ret && CONSTANT_P (ret)) | |
1471 | { | |
1472 | ret = simplify_const_binary_operation (LSHIFTRT, new_mode, | |
1473 | ret, GEN_INT (shift)); | |
1474 | if (ret && CONSTANT_P (ret)) | |
1475 | { | |
1476 | byte = subreg_lowpart_offset (read_mode, new_mode); | |
1477 | ret = simplify_subreg (read_mode, ret, new_mode, byte); | |
1478 | if (ret && CONSTANT_P (ret) | |
1479 | && rtx_cost (ret, SET, speed) <= COSTS_N_INSNS (1)) | |
1480 | return ret; | |
1481 | } | |
1482 | } | |
1483 | } | |
1484 | ||
18b526e8 RS |
1485 | /* Try a wider mode if truncating the store mode to NEW_MODE |
1486 | requires a real instruction. */ | |
1487 | if (GET_MODE_BITSIZE (new_mode) < GET_MODE_BITSIZE (store_mode) | |
1488 | && !TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (new_mode), | |
348eea5f RS |
1489 | GET_MODE_BITSIZE (store_mode))) |
1490 | continue; | |
1491 | ||
18b526e8 RS |
1492 | /* Also try a wider mode if the necessary punning is either not |
1493 | desirable or not possible. */ | |
1494 | if (!CONSTANT_P (store_info->rhs) | |
1495 | && !MODES_TIEABLE_P (new_mode, store_mode)) | |
1496 | continue; | |
18b526e8 | 1497 | |
348eea5f | 1498 | new_reg = gen_reg_rtx (new_mode); |
8660aaae EC |
1499 | |
1500 | start_sequence (); | |
1501 | ||
1502 | /* In theory we could also check for an ashr. Ian Taylor knows | |
1503 | of one dsp where the cost of these two was not the same. But | |
1504 | this really is a rare case anyway. */ | |
1505 | target = expand_binop (new_mode, lshr_optab, new_reg, | |
1506 | GEN_INT (shift), new_reg, 1, OPTAB_DIRECT); | |
1507 | ||
c6f3019a RS |
1508 | shift_seq = get_insns (); |
1509 | end_sequence (); | |
8660aaae | 1510 | |
c6f3019a RS |
1511 | if (target != new_reg || shift_seq == NULL) |
1512 | continue; | |
1513 | ||
1514 | cost = 0; | |
1515 | for (insn = shift_seq; insn != NULL_RTX; insn = NEXT_INSN (insn)) | |
1516 | if (INSN_P (insn)) | |
f40751dd | 1517 | cost += insn_rtx_cost (PATTERN (insn), speed); |
c6f3019a RS |
1518 | |
1519 | /* The computation up to here is essentially independent | |
1520 | of the arguments and could be precomputed. It may | |
1521 | not be worth doing so. We could precompute if | |
1522 | worthwhile or at least cache the results. The result | |
06acf7d0 RS |
1523 | technically depends on both SHIFT and ACCESS_SIZE, |
1524 | but in practice the answer will depend only on ACCESS_SIZE. */ | |
c6f3019a RS |
1525 | |
1526 | if (cost > COSTS_N_INSNS (1)) | |
1527 | continue; | |
1528 | ||
d898d29b JJ |
1529 | new_lhs = extract_low_bits (new_mode, store_mode, |
1530 | copy_rtx (store_info->rhs)); | |
1531 | if (new_lhs == NULL_RTX) | |
1532 | continue; | |
1533 | ||
c6f3019a RS |
1534 | /* We found an acceptable shift. Generate a move to |
1535 | take the value from the store and put it into the | |
1536 | shift pseudo, then shift it, then generate another | |
1537 | move to put in into the target of the read. */ | |
18b526e8 | 1538 | emit_move_insn (new_reg, new_lhs); |
c6f3019a | 1539 | emit_insn (shift_seq); |
18b526e8 | 1540 | read_reg = extract_low_bits (read_mode, new_mode, new_reg); |
c6f3019a | 1541 | break; |
8660aaae EC |
1542 | } |
1543 | ||
18b526e8 | 1544 | return read_reg; |
8660aaae EC |
1545 | } |
1546 | ||
1547 | ||
02b47899 KZ |
1548 | /* Call back for note_stores to find the hard regs set or clobbered by |
1549 | insn. Data is a bitmap of the hardregs set so far. */ | |
1550 | ||
1551 | static void | |
1552 | look_for_hardregs (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) | |
1553 | { | |
1554 | bitmap regs_set = (bitmap) data; | |
1555 | ||
1556 | if (REG_P (x) | |
1557 | && REGNO (x) < FIRST_PSEUDO_REGISTER) | |
1558 | { | |
1559 | int regno = REGNO (x); | |
1560 | int n = hard_regno_nregs[regno][GET_MODE (x)]; | |
1561 | while (--n >= 0) | |
1562 | bitmap_set_bit (regs_set, regno + n); | |
1563 | } | |
1564 | } | |
1565 | ||
1566 | ||
6fb5fa3c DB |
1567 | /* Take a sequence of: |
1568 | A <- r1 | |
1569 | ... | |
1570 | ... <- A | |
1571 | ||
1572 | and change it into | |
1573 | r2 <- r1 | |
1574 | A <- r1 | |
1575 | ... | |
1576 | ... <- r2 | |
1577 | ||
8660aaae EC |
1578 | or |
1579 | ||
1580 | r3 <- extract (r1) | |
1581 | r3 <- r3 >> shift | |
1582 | r2 <- extract (r3) | |
1583 | ... <- r2 | |
1584 | ||
1585 | or | |
1586 | ||
1587 | r2 <- extract (r1) | |
1588 | ... <- r2 | |
1589 | ||
1590 | Depending on the alignment and the mode of the store and | |
1591 | subsequent load. | |
1592 | ||
1593 | ||
1594 | The STORE_INFO and STORE_INSN are for the store and READ_INFO | |
6fb5fa3c DB |
1595 | and READ_INSN are for the read. Return true if the replacement |
1596 | went ok. */ | |
1597 | ||
1598 | static bool | |
1599 | replace_read (store_info_t store_info, insn_info_t store_insn, | |
02b47899 | 1600 | read_info_t read_info, insn_info_t read_insn, rtx *loc, bitmap regs_live) |
6fb5fa3c | 1601 | { |
8660aaae EC |
1602 | enum machine_mode store_mode = GET_MODE (store_info->mem); |
1603 | enum machine_mode read_mode = GET_MODE (read_info->mem); | |
1604 | int shift; | |
1605 | int access_size; /* In bytes. */ | |
02b47899 | 1606 | rtx insns, this_insn, read_reg; |
8660aaae | 1607 | |
6fb5fa3c DB |
1608 | if (!dbg_cnt (dse)) |
1609 | return false; | |
1610 | ||
8660aaae EC |
1611 | /* To get here the read is within the boundaries of the write so |
1612 | shift will never be negative. Start out with the shift being in | |
1613 | bytes. */ | |
1614 | if (BYTES_BIG_ENDIAN) | |
1615 | shift = store_info->end - read_info->end; | |
1616 | else | |
1617 | shift = read_info->begin - store_info->begin; | |
1618 | ||
1619 | access_size = shift + GET_MODE_SIZE (read_mode); | |
1620 | ||
1621 | /* From now on it is bits. */ | |
1622 | shift *= BITS_PER_UNIT; | |
1623 | ||
18b526e8 RS |
1624 | /* Create a sequence of instructions to set up the read register. |
1625 | This sequence goes immediately before the store and its result | |
1626 | is read by the load. | |
1627 | ||
1628 | We need to keep this in perspective. We are replacing a read | |
8660aaae EC |
1629 | with a sequence of insns, but the read will almost certainly be |
1630 | in cache, so it is not going to be an expensive one. Thus, we | |
1631 | are not willing to do a multi insn shift or worse a subroutine | |
1632 | call to get rid of the read. */ | |
18b526e8 RS |
1633 | if (dump_file) |
1634 | fprintf (dump_file, "trying to replace %smode load in insn %d" | |
1635 | " from %smode store in insn %d\n", | |
1636 | GET_MODE_NAME (read_mode), INSN_UID (read_insn->insn), | |
1637 | GET_MODE_NAME (store_mode), INSN_UID (store_insn->insn)); | |
1638 | start_sequence (); | |
8660aaae | 1639 | if (shift) |
f40751dd JH |
1640 | read_reg = find_shift_sequence (access_size, store_info, read_info, shift, |
1641 | optimize_bb_for_speed_p (BLOCK_FOR_INSN (read_insn->insn))); | |
18b526e8 RS |
1642 | else |
1643 | read_reg = extract_low_bits (read_mode, store_mode, | |
1644 | copy_rtx (store_info->rhs)); | |
1645 | if (read_reg == NULL_RTX) | |
8660aaae | 1646 | { |
18b526e8 RS |
1647 | end_sequence (); |
1648 | if (dump_file) | |
1649 | fprintf (dump_file, " -- could not extract bits of stored value\n"); | |
1650 | return false; | |
8660aaae | 1651 | } |
18b526e8 RS |
1652 | /* Force the value into a new register so that it won't be clobbered |
1653 | between the store and the load. */ | |
1654 | read_reg = copy_to_mode_reg (read_mode, read_reg); | |
1655 | insns = get_insns (); | |
1656 | end_sequence (); | |
8660aaae | 1657 | |
02b47899 KZ |
1658 | if (insns != NULL_RTX) |
1659 | { | |
1660 | /* Now we have to scan the set of new instructions to see if the | |
1661 | sequence contains and sets of hardregs that happened to be | |
1662 | live at this point. For instance, this can happen if one of | |
1663 | the insns sets the CC and the CC happened to be live at that | |
1664 | point. This does occasionally happen, see PR 37922. */ | |
1665 | bitmap regs_set = BITMAP_ALLOC (NULL); | |
1666 | ||
1667 | for (this_insn = insns; this_insn != NULL_RTX; this_insn = NEXT_INSN (this_insn)) | |
1668 | note_stores (PATTERN (this_insn), look_for_hardregs, regs_set); | |
1669 | ||
1670 | bitmap_and_into (regs_set, regs_live); | |
1671 | if (!bitmap_empty_p (regs_set)) | |
1672 | { | |
1673 | if (dump_file) | |
1674 | { | |
1675 | fprintf (dump_file, | |
1676 | "abandoning replacement because sequence clobbers live hardregs:"); | |
1677 | df_print_regset (dump_file, regs_set); | |
1678 | } | |
1679 | ||
1680 | BITMAP_FREE (regs_set); | |
1681 | return false; | |
1682 | } | |
1683 | BITMAP_FREE (regs_set); | |
1684 | } | |
1685 | ||
8660aaae | 1686 | if (validate_change (read_insn->insn, loc, read_reg, 0)) |
6fb5fa3c | 1687 | { |
f883e0a7 KG |
1688 | deferred_change_t deferred_change = |
1689 | (deferred_change_t) pool_alloc (deferred_change_pool); | |
8660aaae | 1690 | |
8660aaae EC |
1691 | /* Insert this right before the store insn where it will be safe |
1692 | from later insns that might change it before the read. */ | |
1693 | emit_insn_before (insns, store_insn->insn); | |
1694 | ||
1695 | /* And now for the kludge part: cselib croaks if you just | |
1696 | return at this point. There are two reasons for this: | |
1697 | ||
1698 | 1) Cselib has an idea of how many pseudos there are and | |
1699 | that does not include the new ones we just added. | |
1700 | ||
1701 | 2) Cselib does not know about the move insn we added | |
1702 | above the store_info, and there is no way to tell it | |
1703 | about it, because it has "moved on". | |
1704 | ||
1705 | Problem (1) is fixable with a certain amount of engineering. | |
1706 | Problem (2) is requires starting the bb from scratch. This | |
1707 | could be expensive. | |
1708 | ||
1709 | So we are just going to have to lie. The move/extraction | |
1710 | insns are not really an issue, cselib did not see them. But | |
1711 | the use of the new pseudo read_insn is a real problem because | |
1712 | cselib has not scanned this insn. The way that we solve this | |
1713 | problem is that we are just going to put the mem back for now | |
1714 | and when we are finished with the block, we undo this. We | |
1715 | keep a table of mems to get rid of. At the end of the basic | |
1716 | block we can put them back. */ | |
1717 | ||
1718 | *loc = read_info->mem; | |
1719 | deferred_change->next = deferred_change_list; | |
1720 | deferred_change_list = deferred_change; | |
1721 | deferred_change->loc = loc; | |
1722 | deferred_change->reg = read_reg; | |
1723 | ||
1724 | /* Get rid of the read_info, from the point of view of the | |
1725 | rest of dse, play like this read never happened. */ | |
1726 | read_insn->read_rec = read_info->next; | |
1727 | pool_free (read_info_pool, read_info); | |
18b526e8 RS |
1728 | if (dump_file) |
1729 | { | |
1730 | fprintf (dump_file, " -- replaced the loaded MEM with "); | |
1731 | print_simple_rtl (dump_file, read_reg); | |
1732 | fprintf (dump_file, "\n"); | |
1733 | } | |
8660aaae | 1734 | return true; |
6fb5fa3c | 1735 | } |
8660aaae | 1736 | else |
6fb5fa3c | 1737 | { |
6fb5fa3c | 1738 | if (dump_file) |
18b526e8 RS |
1739 | { |
1740 | fprintf (dump_file, " -- replacing the loaded MEM with "); | |
1741 | print_simple_rtl (dump_file, read_reg); | |
1742 | fprintf (dump_file, " led to an invalid instruction\n"); | |
1743 | } | |
6fb5fa3c DB |
1744 | return false; |
1745 | } | |
1746 | } | |
1747 | ||
6fb5fa3c DB |
1748 | /* A for_each_rtx callback in which DATA is the bb_info. Check to see |
1749 | if LOC is a mem and if it is look at the address and kill any | |
1750 | appropriate stores that may be active. */ | |
1751 | ||
1752 | static int | |
1753 | check_mem_read_rtx (rtx *loc, void *data) | |
1754 | { | |
1755 | rtx mem = *loc; | |
1756 | bb_info_t bb_info; | |
1757 | insn_info_t insn_info; | |
1758 | HOST_WIDE_INT offset = 0; | |
1759 | HOST_WIDE_INT width = 0; | |
4862826d | 1760 | alias_set_type spill_alias_set = 0; |
6fb5fa3c DB |
1761 | cselib_val *base = NULL; |
1762 | int group_id; | |
1763 | read_info_t read_info; | |
1764 | ||
1765 | if (!mem || !MEM_P (mem)) | |
1766 | return 0; | |
1767 | ||
1768 | bb_info = (bb_info_t) data; | |
1769 | insn_info = bb_info->last_insn; | |
1770 | ||
1771 | if ((MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
1772 | || (MEM_VOLATILE_P (mem))) | |
1773 | { | |
1774 | if (dump_file) | |
1775 | fprintf (dump_file, " adding wild read, volatile or barrier.\n"); | |
1776 | add_wild_read (bb_info); | |
1777 | insn_info->cannot_delete = true; | |
1778 | return 0; | |
1779 | } | |
1780 | ||
1781 | /* If it is reading readonly mem, then there can be no conflict with | |
1782 | another write. */ | |
1783 | if (MEM_READONLY_P (mem)) | |
1784 | return 0; | |
1785 | ||
1786 | if (!canon_address (mem, &spill_alias_set, &group_id, &offset, &base)) | |
1787 | { | |
1788 | if (dump_file) | |
1789 | fprintf (dump_file, " adding wild read, canon_address failure.\n"); | |
1790 | add_wild_read (bb_info); | |
1791 | return 0; | |
1792 | } | |
1793 | ||
1794 | if (GET_MODE (mem) == BLKmode) | |
1795 | width = -1; | |
1796 | else | |
1797 | width = GET_MODE_SIZE (GET_MODE (mem)); | |
1798 | ||
f883e0a7 | 1799 | read_info = (read_info_t) pool_alloc (read_info_pool); |
6fb5fa3c DB |
1800 | read_info->group_id = group_id; |
1801 | read_info->mem = mem; | |
1802 | read_info->alias_set = spill_alias_set; | |
1803 | read_info->begin = offset; | |
1804 | read_info->end = offset + width; | |
1805 | read_info->next = insn_info->read_rec; | |
1806 | insn_info->read_rec = read_info; | |
1807 | ||
0d52bcc1 | 1808 | /* We ignore the clobbers in store_info. The is mildly aggressive, |
6fb5fa3c DB |
1809 | but there really should not be a clobber followed by a read. */ |
1810 | ||
1811 | if (spill_alias_set) | |
1812 | { | |
1813 | insn_info_t i_ptr = active_local_stores; | |
1814 | insn_info_t last = NULL; | |
1815 | ||
1816 | if (dump_file) | |
1817 | fprintf (dump_file, " processing spill load %d\n", | |
4862826d | 1818 | (int) spill_alias_set); |
6fb5fa3c DB |
1819 | |
1820 | while (i_ptr) | |
1821 | { | |
1822 | store_info_t store_info = i_ptr->store_rec; | |
1823 | ||
1824 | /* Skip the clobbers. */ | |
1825 | while (!store_info->is_set) | |
1826 | store_info = store_info->next; | |
1827 | ||
1828 | if (store_info->alias_set == spill_alias_set) | |
1829 | { | |
1830 | if (dump_file) | |
1831 | dump_insn_info ("removing from active", i_ptr); | |
1832 | ||
1833 | if (last) | |
1834 | last->next_local_store = i_ptr->next_local_store; | |
1835 | else | |
1836 | active_local_stores = i_ptr->next_local_store; | |
1837 | } | |
1838 | else | |
1839 | last = i_ptr; | |
1840 | i_ptr = i_ptr->next_local_store; | |
1841 | } | |
1842 | } | |
1843 | else if (group_id >= 0) | |
1844 | { | |
1845 | /* This is the restricted case where the base is a constant or | |
1846 | the frame pointer and offset is a constant. */ | |
1847 | insn_info_t i_ptr = active_local_stores; | |
1848 | insn_info_t last = NULL; | |
1849 | ||
1850 | if (dump_file) | |
1851 | { | |
1852 | if (width == -1) | |
1853 | fprintf (dump_file, " processing const load gid=%d[BLK]\n", | |
1854 | group_id); | |
1855 | else | |
1856 | fprintf (dump_file, " processing const load gid=%d[%d..%d)\n", | |
1857 | group_id, (int)offset, (int)(offset+width)); | |
1858 | } | |
1859 | ||
1860 | while (i_ptr) | |
1861 | { | |
1862 | bool remove = false; | |
1863 | store_info_t store_info = i_ptr->store_rec; | |
1864 | ||
1865 | /* Skip the clobbers. */ | |
1866 | while (!store_info->is_set) | |
1867 | store_info = store_info->next; | |
1868 | ||
1869 | /* There are three cases here. */ | |
1870 | if (store_info->group_id < 0) | |
1871 | /* We have a cselib store followed by a read from a | |
1872 | const base. */ | |
1873 | remove | |
1874 | = canon_true_dependence (store_info->mem, | |
1875 | GET_MODE (store_info->mem), | |
1876 | store_info->mem_addr, | |
1877 | mem, rtx_varies_p); | |
1878 | ||
1879 | else if (group_id == store_info->group_id) | |
1880 | { | |
1881 | /* This is a block mode load. We may get lucky and | |
1882 | canon_true_dependence may save the day. */ | |
1883 | if (width == -1) | |
1884 | remove | |
1885 | = canon_true_dependence (store_info->mem, | |
1886 | GET_MODE (store_info->mem), | |
1887 | store_info->mem_addr, | |
1888 | mem, rtx_varies_p); | |
1889 | ||
1890 | /* If this read is just reading back something that we just | |
1891 | stored, rewrite the read. */ | |
1892 | else | |
1893 | { | |
1894 | if (store_info->rhs | |
1895 | && (offset >= store_info->begin) | |
1896 | && (offset + width <= store_info->end)) | |
1897 | { | |
4fe663b0 L |
1898 | unsigned HOST_WIDE_INT mask |
1899 | = (lowpart_bitmask (width) | |
1900 | << (offset - store_info->begin)); | |
1901 | ||
6fb5fa3c DB |
1902 | if ((store_info->positions_needed & mask) == mask |
1903 | && replace_read (store_info, i_ptr, | |
02b47899 | 1904 | read_info, insn_info, loc, bb_info->regs_live)) |
6fb5fa3c DB |
1905 | return 0; |
1906 | } | |
1907 | /* The bases are the same, just see if the offsets | |
1908 | overlap. */ | |
1909 | if ((offset < store_info->end) | |
1910 | && (offset + width > store_info->begin)) | |
1911 | remove = true; | |
1912 | } | |
1913 | } | |
1914 | ||
1915 | /* else | |
1916 | The else case that is missing here is that the | |
1917 | bases are constant but different. There is nothing | |
1918 | to do here because there is no overlap. */ | |
1919 | ||
1920 | if (remove) | |
1921 | { | |
1922 | if (dump_file) | |
1923 | dump_insn_info ("removing from active", i_ptr); | |
1924 | ||
1925 | if (last) | |
1926 | last->next_local_store = i_ptr->next_local_store; | |
1927 | else | |
1928 | active_local_stores = i_ptr->next_local_store; | |
1929 | } | |
1930 | else | |
1931 | last = i_ptr; | |
1932 | i_ptr = i_ptr->next_local_store; | |
1933 | } | |
1934 | } | |
1935 | else | |
1936 | { | |
1937 | insn_info_t i_ptr = active_local_stores; | |
1938 | insn_info_t last = NULL; | |
1939 | if (dump_file) | |
1940 | { | |
1941 | fprintf (dump_file, " processing cselib load mem:"); | |
1942 | print_inline_rtx (dump_file, mem, 0); | |
1943 | fprintf (dump_file, "\n"); | |
1944 | } | |
1945 | ||
1946 | while (i_ptr) | |
1947 | { | |
1948 | bool remove = false; | |
1949 | store_info_t store_info = i_ptr->store_rec; | |
1950 | ||
1951 | if (dump_file) | |
1952 | fprintf (dump_file, " processing cselib load against insn %d\n", | |
1953 | INSN_UID (i_ptr->insn)); | |
1954 | ||
1955 | /* Skip the clobbers. */ | |
1956 | while (!store_info->is_set) | |
1957 | store_info = store_info->next; | |
1958 | ||
1959 | /* If this read is just reading back something that we just | |
1960 | stored, rewrite the read. */ | |
1961 | if (store_info->rhs | |
1962 | && store_info->group_id == -1 | |
1963 | && store_info->cse_base == base | |
1964 | && (offset >= store_info->begin) | |
1965 | && (offset + width <= store_info->end)) | |
1966 | { | |
4fe663b0 L |
1967 | unsigned HOST_WIDE_INT mask |
1968 | = (lowpart_bitmask (width) | |
1969 | << (offset - store_info->begin)); | |
1970 | ||
6fb5fa3c DB |
1971 | if ((store_info->positions_needed & mask) == mask |
1972 | && replace_read (store_info, i_ptr, | |
02b47899 | 1973 | read_info, insn_info, loc, bb_info->regs_live)) |
6fb5fa3c DB |
1974 | return 0; |
1975 | } | |
1976 | ||
1977 | if (!store_info->alias_set) | |
1978 | remove = canon_true_dependence (store_info->mem, | |
1979 | GET_MODE (store_info->mem), | |
1980 | store_info->mem_addr, | |
1981 | mem, rtx_varies_p); | |
1982 | ||
1983 | if (remove) | |
1984 | { | |
1985 | if (dump_file) | |
1986 | dump_insn_info ("removing from active", i_ptr); | |
1987 | ||
1988 | if (last) | |
1989 | last->next_local_store = i_ptr->next_local_store; | |
1990 | else | |
1991 | active_local_stores = i_ptr->next_local_store; | |
1992 | } | |
1993 | else | |
1994 | last = i_ptr; | |
1995 | i_ptr = i_ptr->next_local_store; | |
1996 | } | |
1997 | } | |
1998 | return 0; | |
1999 | } | |
2000 | ||
2001 | /* A for_each_rtx callback in which DATA points the INSN_INFO for | |
2002 | as check_mem_read_rtx. Nullify the pointer if i_m_r_m_r returns | |
2003 | true for any part of *LOC. */ | |
2004 | ||
2005 | static void | |
2006 | check_mem_read_use (rtx *loc, void *data) | |
2007 | { | |
2008 | for_each_rtx (loc, check_mem_read_rtx, data); | |
2009 | } | |
2010 | ||
2011 | /* Apply record_store to all candidate stores in INSN. Mark INSN | |
2012 | if some part of it is not a candidate store and assigns to a | |
2013 | non-register target. */ | |
2014 | ||
2015 | static void | |
2016 | scan_insn (bb_info_t bb_info, rtx insn) | |
2017 | { | |
2018 | rtx body; | |
f883e0a7 | 2019 | insn_info_t insn_info = (insn_info_t) pool_alloc (insn_info_pool); |
6fb5fa3c DB |
2020 | int mems_found = 0; |
2021 | memset (insn_info, 0, sizeof (struct insn_info)); | |
2022 | ||
2023 | if (dump_file) | |
2024 | fprintf (dump_file, "\n**scanning insn=%d\n", | |
2025 | INSN_UID (insn)); | |
2026 | ||
2027 | insn_info->prev_insn = bb_info->last_insn; | |
2028 | insn_info->insn = insn; | |
2029 | bb_info->last_insn = insn_info; | |
2030 | ||
2031 | ||
0d52bcc1 | 2032 | /* Cselib clears the table for this case, so we have to essentially |
6fb5fa3c DB |
2033 | do the same. */ |
2034 | if (NONJUMP_INSN_P (insn) | |
2035 | && GET_CODE (PATTERN (insn)) == ASM_OPERANDS | |
2036 | && MEM_VOLATILE_P (PATTERN (insn))) | |
2037 | { | |
2038 | add_wild_read (bb_info); | |
2039 | insn_info->cannot_delete = true; | |
2040 | return; | |
2041 | } | |
2042 | ||
2043 | /* Look at all of the uses in the insn. */ | |
2044 | note_uses (&PATTERN (insn), check_mem_read_use, bb_info); | |
2045 | ||
2046 | if (CALL_P (insn)) | |
2047 | { | |
2048 | insn_info->cannot_delete = true; | |
50f0f366 | 2049 | |
6fb5fa3c | 2050 | /* Const functions cannot do anything bad i.e. read memory, |
50f0f366 EB |
2051 | however, they can read their parameters which may have |
2052 | been pushed onto the stack. */ | |
becfd6e5 | 2053 | if (RTL_CONST_CALL_P (insn)) |
6fb5fa3c DB |
2054 | { |
2055 | insn_info_t i_ptr = active_local_stores; | |
2056 | insn_info_t last = NULL; | |
2057 | ||
2058 | if (dump_file) | |
2059 | fprintf (dump_file, "const call %d\n", INSN_UID (insn)); | |
2060 | ||
64520bdc EB |
2061 | /* See the head comment of the frame_read field. */ |
2062 | if (reload_completed) | |
2063 | insn_info->frame_read = true; | |
2064 | ||
2065 | /* Loop over the active stores and remove those which are | |
2066 | killed by the const function call. */ | |
6fb5fa3c DB |
2067 | while (i_ptr) |
2068 | { | |
64520bdc EB |
2069 | bool remove_store = false; |
2070 | ||
2071 | /* The stack pointer based stores are always killed. */ | |
50f0f366 | 2072 | if (i_ptr->stack_pointer_based) |
64520bdc EB |
2073 | remove_store = true; |
2074 | ||
2075 | /* If the frame is read, the frame related stores are killed. */ | |
2076 | else if (insn_info->frame_read) | |
2077 | { | |
2078 | store_info_t store_info = i_ptr->store_rec; | |
2079 | ||
2080 | /* Skip the clobbers. */ | |
2081 | while (!store_info->is_set) | |
2082 | store_info = store_info->next; | |
2083 | ||
2084 | if (store_info->group_id >= 0 | |
2085 | && VEC_index (group_info_t, rtx_group_vec, | |
2086 | store_info->group_id)->frame_related) | |
2087 | remove_store = true; | |
2088 | } | |
2089 | ||
2090 | if (remove_store) | |
6fb5fa3c DB |
2091 | { |
2092 | if (dump_file) | |
2093 | dump_insn_info ("removing from active", i_ptr); | |
2094 | ||
2095 | if (last) | |
2096 | last->next_local_store = i_ptr->next_local_store; | |
2097 | else | |
2098 | active_local_stores = i_ptr->next_local_store; | |
2099 | } | |
2100 | else | |
2101 | last = i_ptr; | |
64520bdc | 2102 | |
6fb5fa3c DB |
2103 | i_ptr = i_ptr->next_local_store; |
2104 | } | |
6fb5fa3c DB |
2105 | } |
2106 | ||
50f0f366 EB |
2107 | else |
2108 | /* Every other call, including pure functions, may read memory. */ | |
2109 | add_wild_read (bb_info); | |
2110 | ||
6fb5fa3c DB |
2111 | return; |
2112 | } | |
2113 | ||
2114 | /* Assuming that there are sets in these insns, we cannot delete | |
2115 | them. */ | |
2116 | if ((GET_CODE (PATTERN (insn)) == CLOBBER) | |
0a64eeca | 2117 | || volatile_refs_p (PATTERN (insn)) |
6fb5fa3c DB |
2118 | || (flag_non_call_exceptions && may_trap_p (PATTERN (insn))) |
2119 | || (RTX_FRAME_RELATED_P (insn)) | |
2120 | || find_reg_note (insn, REG_FRAME_RELATED_EXPR, NULL_RTX)) | |
2121 | insn_info->cannot_delete = true; | |
2122 | ||
2123 | body = PATTERN (insn); | |
2124 | if (GET_CODE (body) == PARALLEL) | |
2125 | { | |
2126 | int i; | |
2127 | for (i = 0; i < XVECLEN (body, 0); i++) | |
2128 | mems_found += record_store (XVECEXP (body, 0, i), bb_info); | |
2129 | } | |
2130 | else | |
2131 | mems_found += record_store (body, bb_info); | |
2132 | ||
2133 | if (dump_file) | |
2134 | fprintf (dump_file, "mems_found = %d, cannot_delete = %s\n", | |
2135 | mems_found, insn_info->cannot_delete ? "true" : "false"); | |
2136 | ||
2137 | /* If we found some sets of mems, and the insn has not been marked | |
2138 | cannot delete, add it into the active_local_stores so that it can | |
2139 | be locally deleted if found dead. Otherwise mark it as cannot | |
2140 | delete. This simplifies the processing later. */ | |
2141 | if (mems_found == 1 && !insn_info->cannot_delete) | |
2142 | { | |
2143 | insn_info->next_local_store = active_local_stores; | |
2144 | active_local_stores = insn_info; | |
2145 | } | |
2146 | else | |
2147 | insn_info->cannot_delete = true; | |
2148 | } | |
2149 | ||
2150 | ||
2151 | /* Remove BASE from the set of active_local_stores. This is a | |
2152 | callback from cselib that is used to get rid of the stores in | |
2153 | active_local_stores. */ | |
2154 | ||
2155 | static void | |
2156 | remove_useless_values (cselib_val *base) | |
2157 | { | |
2158 | insn_info_t insn_info = active_local_stores; | |
2159 | insn_info_t last = NULL; | |
2160 | ||
2161 | while (insn_info) | |
2162 | { | |
2163 | store_info_t store_info = insn_info->store_rec; | |
60564289 | 2164 | bool del = false; |
6fb5fa3c DB |
2165 | |
2166 | /* If ANY of the store_infos match the cselib group that is | |
2167 | being deleted, then the insn can not be deleted. */ | |
2168 | while (store_info) | |
2169 | { | |
2170 | if ((store_info->group_id == -1) | |
2171 | && (store_info->cse_base == base)) | |
2172 | { | |
60564289 | 2173 | del = true; |
6fb5fa3c DB |
2174 | break; |
2175 | } | |
2176 | store_info = store_info->next; | |
2177 | } | |
2178 | ||
60564289 | 2179 | if (del) |
6fb5fa3c DB |
2180 | { |
2181 | if (last) | |
2182 | last->next_local_store = insn_info->next_local_store; | |
2183 | else | |
2184 | active_local_stores = insn_info->next_local_store; | |
2185 | free_store_info (insn_info); | |
2186 | } | |
2187 | else | |
2188 | last = insn_info; | |
2189 | ||
2190 | insn_info = insn_info->next_local_store; | |
2191 | } | |
2192 | } | |
2193 | ||
2194 | ||
2195 | /* Do all of step 1. */ | |
2196 | ||
2197 | static void | |
2198 | dse_step1 (void) | |
2199 | { | |
2200 | basic_block bb; | |
02b47899 KZ |
2201 | bitmap regs_live = BITMAP_ALLOC (NULL); |
2202 | ||
6fb5fa3c DB |
2203 | cselib_init (false); |
2204 | all_blocks = BITMAP_ALLOC (NULL); | |
2205 | bitmap_set_bit (all_blocks, ENTRY_BLOCK); | |
2206 | bitmap_set_bit (all_blocks, EXIT_BLOCK); | |
2207 | ||
2208 | FOR_ALL_BB (bb) | |
2209 | { | |
2210 | insn_info_t ptr; | |
f883e0a7 | 2211 | bb_info_t bb_info = (bb_info_t) pool_alloc (bb_info_pool); |
6fb5fa3c DB |
2212 | |
2213 | memset (bb_info, 0, sizeof (struct bb_info)); | |
2214 | bitmap_set_bit (all_blocks, bb->index); | |
02b47899 KZ |
2215 | bb_info->regs_live = regs_live; |
2216 | ||
2217 | bitmap_copy (regs_live, DF_LR_IN (bb)); | |
2218 | df_simulate_initialize_forwards (bb, regs_live); | |
6fb5fa3c DB |
2219 | |
2220 | bb_table[bb->index] = bb_info; | |
2221 | cselib_discard_hook = remove_useless_values; | |
2222 | ||
2223 | if (bb->index >= NUM_FIXED_BLOCKS) | |
2224 | { | |
2225 | rtx insn; | |
2226 | ||
2227 | cse_store_info_pool | |
2228 | = create_alloc_pool ("cse_store_info_pool", | |
2229 | sizeof (struct store_info), 100); | |
2230 | active_local_stores = NULL; | |
2231 | cselib_clear_table (); | |
2232 | ||
2233 | /* Scan the insns. */ | |
2234 | FOR_BB_INSNS (bb, insn) | |
2235 | { | |
2236 | if (INSN_P (insn)) | |
2237 | scan_insn (bb_info, insn); | |
2238 | cselib_process_insn (insn); | |
02b47899 KZ |
2239 | if (INSN_P (insn)) |
2240 | df_simulate_one_insn_forwards (bb, insn, regs_live); | |
6fb5fa3c DB |
2241 | } |
2242 | ||
2243 | /* This is something of a hack, because the global algorithm | |
2244 | is supposed to take care of the case where stores go dead | |
2245 | at the end of the function. However, the global | |
2246 | algorithm must take a more conservative view of block | |
2247 | mode reads than the local alg does. So to get the case | |
2248 | where you have a store to the frame followed by a non | |
0d52bcc1 | 2249 | overlapping block more read, we look at the active local |
6fb5fa3c DB |
2250 | stores at the end of the function and delete all of the |
2251 | frame and spill based ones. */ | |
2252 | if (stores_off_frame_dead_at_return | |
2253 | && (EDGE_COUNT (bb->succs) == 0 | |
2254 | || (single_succ_p (bb) | |
2255 | && single_succ (bb) == EXIT_BLOCK_PTR | |
e3b5732b | 2256 | && ! crtl->calls_eh_return))) |
6fb5fa3c DB |
2257 | { |
2258 | insn_info_t i_ptr = active_local_stores; | |
2259 | while (i_ptr) | |
2260 | { | |
2261 | store_info_t store_info = i_ptr->store_rec; | |
2262 | ||
2263 | /* Skip the clobbers. */ | |
2264 | while (!store_info->is_set) | |
2265 | store_info = store_info->next; | |
2266 | if (store_info->alias_set) | |
2267 | delete_dead_store_insn (i_ptr); | |
2268 | else | |
2269 | if (store_info->group_id >= 0) | |
2270 | { | |
2271 | group_info_t group | |
2272 | = VEC_index (group_info_t, rtx_group_vec, store_info->group_id); | |
2273 | if (group->frame_related) | |
2274 | delete_dead_store_insn (i_ptr); | |
2275 | } | |
2276 | ||
2277 | i_ptr = i_ptr->next_local_store; | |
2278 | } | |
2279 | } | |
2280 | ||
2281 | /* Get rid of the loads that were discovered in | |
2282 | replace_read. Cselib is finished with this block. */ | |
2283 | while (deferred_change_list) | |
2284 | { | |
2285 | deferred_change_t next = deferred_change_list->next; | |
2286 | ||
2287 | /* There is no reason to validate this change. That was | |
2288 | done earlier. */ | |
2289 | *deferred_change_list->loc = deferred_change_list->reg; | |
2290 | pool_free (deferred_change_pool, deferred_change_list); | |
2291 | deferred_change_list = next; | |
2292 | } | |
2293 | ||
2294 | /* Get rid of all of the cselib based store_infos in this | |
2295 | block and mark the containing insns as not being | |
2296 | deletable. */ | |
2297 | ptr = bb_info->last_insn; | |
2298 | while (ptr) | |
2299 | { | |
2300 | if (ptr->contains_cselib_groups) | |
2301 | free_store_info (ptr); | |
2302 | ptr = ptr->prev_insn; | |
2303 | } | |
2304 | ||
2305 | free_alloc_pool (cse_store_info_pool); | |
2306 | } | |
02b47899 | 2307 | bb_info->regs_live = NULL; |
6fb5fa3c DB |
2308 | } |
2309 | ||
02b47899 | 2310 | BITMAP_FREE (regs_live); |
6fb5fa3c DB |
2311 | cselib_finish (); |
2312 | htab_empty (rtx_group_table); | |
2313 | } | |
2314 | ||
2315 | \f | |
2316 | /*---------------------------------------------------------------------------- | |
2317 | Second step. | |
2318 | ||
2319 | Assign each byte position in the stores that we are going to | |
2320 | analyze globally to a position in the bitmaps. Returns true if | |
6ed3da00 | 2321 | there are any bit positions assigned. |
6fb5fa3c DB |
2322 | ----------------------------------------------------------------------------*/ |
2323 | ||
2324 | static void | |
2325 | dse_step2_init (void) | |
2326 | { | |
2327 | unsigned int i; | |
2328 | group_info_t group; | |
2329 | ||
2330 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) | |
2331 | { | |
2332 | /* For all non stack related bases, we only consider a store to | |
2333 | be deletable if there are two or more stores for that | |
2334 | position. This is because it takes one store to make the | |
2335 | other store redundant. However, for the stores that are | |
2336 | stack related, we consider them if there is only one store | |
2337 | for the position. We do this because the stack related | |
2338 | stores can be deleted if their is no read between them and | |
2339 | the end of the function. | |
2340 | ||
2341 | To make this work in the current framework, we take the stack | |
2342 | related bases add all of the bits from store1 into store2. | |
2343 | This has the effect of making the eligible even if there is | |
2344 | only one store. */ | |
2345 | ||
2346 | if (stores_off_frame_dead_at_return && group->frame_related) | |
2347 | { | |
2348 | bitmap_ior_into (group->store2_n, group->store1_n); | |
2349 | bitmap_ior_into (group->store2_p, group->store1_p); | |
2350 | if (dump_file) | |
2351 | fprintf (dump_file, "group %d is frame related ", i); | |
2352 | } | |
2353 | ||
2354 | group->offset_map_size_n++; | |
2355 | group->offset_map_n = XNEWVEC (int, group->offset_map_size_n); | |
2356 | group->offset_map_size_p++; | |
2357 | group->offset_map_p = XNEWVEC (int, group->offset_map_size_p); | |
2358 | group->process_globally = false; | |
2359 | if (dump_file) | |
2360 | { | |
2361 | fprintf (dump_file, "group %d(%d+%d): ", i, | |
2362 | (int)bitmap_count_bits (group->store2_n), | |
2363 | (int)bitmap_count_bits (group->store2_p)); | |
2364 | bitmap_print (dump_file, group->store2_n, "n ", " "); | |
2365 | bitmap_print (dump_file, group->store2_p, "p ", "\n"); | |
2366 | } | |
2367 | } | |
2368 | } | |
2369 | ||
2370 | ||
2371 | /* Init the offset tables for the normal case. */ | |
2372 | ||
2373 | static bool | |
2374 | dse_step2_nospill (void) | |
2375 | { | |
2376 | unsigned int i; | |
2377 | group_info_t group; | |
2378 | /* Position 0 is unused because 0 is used in the maps to mean | |
2379 | unused. */ | |
2380 | current_position = 1; | |
2381 | ||
2382 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) | |
2383 | { | |
2384 | bitmap_iterator bi; | |
2385 | unsigned int j; | |
2386 | ||
2387 | if (group == clear_alias_group) | |
2388 | continue; | |
2389 | ||
2390 | memset (group->offset_map_n, 0, sizeof(int) * group->offset_map_size_n); | |
2391 | memset (group->offset_map_p, 0, sizeof(int) * group->offset_map_size_p); | |
2392 | bitmap_clear (group->group_kill); | |
2393 | ||
2394 | EXECUTE_IF_SET_IN_BITMAP (group->store2_n, 0, j, bi) | |
2395 | { | |
2396 | bitmap_set_bit (group->group_kill, current_position); | |
2397 | group->offset_map_n[j] = current_position++; | |
2398 | group->process_globally = true; | |
2399 | } | |
2400 | EXECUTE_IF_SET_IN_BITMAP (group->store2_p, 0, j, bi) | |
2401 | { | |
2402 | bitmap_set_bit (group->group_kill, current_position); | |
2403 | group->offset_map_p[j] = current_position++; | |
2404 | group->process_globally = true; | |
2405 | } | |
2406 | } | |
2407 | return current_position != 1; | |
2408 | } | |
2409 | ||
2410 | ||
2411 | /* Init the offset tables for the spill case. */ | |
2412 | ||
2413 | static bool | |
2414 | dse_step2_spill (void) | |
2415 | { | |
2416 | unsigned int j; | |
2417 | group_info_t group = clear_alias_group; | |
2418 | bitmap_iterator bi; | |
2419 | ||
2420 | /* Position 0 is unused because 0 is used in the maps to mean | |
2421 | unused. */ | |
2422 | current_position = 1; | |
2423 | ||
2424 | if (dump_file) | |
2425 | { | |
2426 | bitmap_print (dump_file, clear_alias_sets, | |
2427 | "clear alias sets ", "\n"); | |
2428 | bitmap_print (dump_file, disqualified_clear_alias_sets, | |
2429 | "disqualified clear alias sets ", "\n"); | |
2430 | } | |
2431 | ||
2432 | memset (group->offset_map_n, 0, sizeof(int) * group->offset_map_size_n); | |
2433 | memset (group->offset_map_p, 0, sizeof(int) * group->offset_map_size_p); | |
2434 | bitmap_clear (group->group_kill); | |
2435 | ||
2436 | /* Remove the disqualified positions from the store2_p set. */ | |
2437 | bitmap_and_compl_into (group->store2_p, disqualified_clear_alias_sets); | |
2438 | ||
2439 | /* We do not need to process the store2_n set because | |
2440 | alias_sets are always positive. */ | |
2441 | EXECUTE_IF_SET_IN_BITMAP (group->store2_p, 0, j, bi) | |
2442 | { | |
2443 | bitmap_set_bit (group->group_kill, current_position); | |
2444 | group->offset_map_p[j] = current_position++; | |
2445 | group->process_globally = true; | |
2446 | } | |
2447 | ||
2448 | return current_position != 1; | |
2449 | } | |
2450 | ||
2451 | ||
2452 | \f | |
2453 | /*---------------------------------------------------------------------------- | |
2454 | Third step. | |
2455 | ||
2456 | Build the bit vectors for the transfer functions. | |
2457 | ----------------------------------------------------------------------------*/ | |
2458 | ||
2459 | ||
2460 | /* Note that this is NOT a general purpose function. Any mem that has | |
2461 | an alias set registered here expected to be COMPLETELY unaliased: | |
2462 | i.e it's addresses are not and need not be examined. | |
2463 | ||
2464 | It is known that all references to this address will have this | |
2465 | alias set and there are NO other references to this address in the | |
2466 | function. | |
2467 | ||
2468 | Currently the only place that is known to be clean enough to use | |
2469 | this interface is the code that assigns the spill locations. | |
2470 | ||
2471 | All of the mems that have alias_sets registered are subjected to a | |
2472 | very powerful form of dse where function calls, volatile reads and | |
2473 | writes, and reads from random location are not taken into account. | |
2474 | ||
2475 | It is also assumed that these locations go dead when the function | |
2476 | returns. This assumption could be relaxed if there were found to | |
2477 | be places that this assumption was not correct. | |
2478 | ||
2479 | The MODE is passed in and saved. The mode of each load or store to | |
2480 | a mem with ALIAS_SET is checked against MEM. If the size of that | |
2481 | load or store is different from MODE, processing is halted on this | |
2482 | alias set. For the vast majority of aliases sets, all of the loads | |
2483 | and stores will use the same mode. But vectors are treated | |
2484 | differently: the alias set is established for the entire vector, | |
2485 | but reload will insert loads and stores for individual elements and | |
2486 | we do not necessarily have the information to track those separate | |
2487 | elements. So when we see a mode mismatch, we just bail. */ | |
2488 | ||
2489 | ||
2490 | void | |
4862826d | 2491 | dse_record_singleton_alias_set (alias_set_type alias_set, |
6fb5fa3c DB |
2492 | enum machine_mode mode) |
2493 | { | |
2494 | struct clear_alias_mode_holder tmp_holder; | |
2495 | struct clear_alias_mode_holder *entry; | |
2496 | void **slot; | |
2497 | ||
2498 | /* If we are not going to run dse, we need to return now or there | |
2499 | will be problems with allocating the bitmaps. */ | |
2500 | if ((!gate_dse()) || !alias_set) | |
2501 | return; | |
2502 | ||
2503 | if (!clear_alias_sets) | |
2504 | { | |
2505 | clear_alias_sets = BITMAP_ALLOC (NULL); | |
2506 | disqualified_clear_alias_sets = BITMAP_ALLOC (NULL); | |
2507 | clear_alias_mode_table = htab_create (11, clear_alias_mode_hash, | |
2508 | clear_alias_mode_eq, NULL); | |
2509 | clear_alias_mode_pool = create_alloc_pool ("clear_alias_mode_pool", | |
2510 | sizeof (struct clear_alias_mode_holder), 100); | |
2511 | } | |
2512 | ||
2513 | bitmap_set_bit (clear_alias_sets, alias_set); | |
2514 | ||
2515 | tmp_holder.alias_set = alias_set; | |
2516 | ||
2517 | slot = htab_find_slot (clear_alias_mode_table, &tmp_holder, INSERT); | |
2518 | gcc_assert (*slot == NULL); | |
2519 | ||
f883e0a7 KG |
2520 | *slot = entry = |
2521 | (struct clear_alias_mode_holder *) pool_alloc (clear_alias_mode_pool); | |
6fb5fa3c DB |
2522 | entry->alias_set = alias_set; |
2523 | entry->mode = mode; | |
2524 | } | |
2525 | ||
2526 | ||
2527 | /* Remove ALIAS_SET from the sets of stack slots being considered. */ | |
2528 | ||
2529 | void | |
4862826d | 2530 | dse_invalidate_singleton_alias_set (alias_set_type alias_set) |
6fb5fa3c DB |
2531 | { |
2532 | if ((!gate_dse()) || !alias_set) | |
2533 | return; | |
2534 | ||
2535 | bitmap_clear_bit (clear_alias_sets, alias_set); | |
2536 | } | |
2537 | ||
2538 | ||
2539 | /* Look up the bitmap index for OFFSET in GROUP_INFO. If it is not | |
2540 | there, return 0. */ | |
2541 | ||
2542 | static int | |
2543 | get_bitmap_index (group_info_t group_info, HOST_WIDE_INT offset) | |
2544 | { | |
2545 | if (offset < 0) | |
2546 | { | |
2547 | HOST_WIDE_INT offset_p = -offset; | |
2548 | if (offset_p >= group_info->offset_map_size_n) | |
2549 | return 0; | |
2550 | return group_info->offset_map_n[offset_p]; | |
2551 | } | |
2552 | else | |
2553 | { | |
2554 | if (offset >= group_info->offset_map_size_p) | |
2555 | return 0; | |
2556 | return group_info->offset_map_p[offset]; | |
2557 | } | |
2558 | } | |
2559 | ||
2560 | ||
2561 | /* Process the STORE_INFOs into the bitmaps into GEN and KILL. KILL | |
2562 | may be NULL. */ | |
2563 | ||
2564 | static void | |
2565 | scan_stores_nospill (store_info_t store_info, bitmap gen, bitmap kill) | |
2566 | { | |
2567 | while (store_info) | |
2568 | { | |
2569 | HOST_WIDE_INT i; | |
2570 | group_info_t group_info | |
2571 | = VEC_index (group_info_t, rtx_group_vec, store_info->group_id); | |
2572 | if (group_info->process_globally) | |
2573 | for (i = store_info->begin; i < store_info->end; i++) | |
2574 | { | |
2575 | int index = get_bitmap_index (group_info, i); | |
2576 | if (index != 0) | |
2577 | { | |
2578 | bitmap_set_bit (gen, index); | |
2579 | if (kill) | |
2580 | bitmap_clear_bit (kill, index); | |
2581 | } | |
2582 | } | |
2583 | store_info = store_info->next; | |
2584 | } | |
2585 | } | |
2586 | ||
2587 | ||
2588 | /* Process the STORE_INFOs into the bitmaps into GEN and KILL. KILL | |
2589 | may be NULL. */ | |
2590 | ||
2591 | static void | |
2592 | scan_stores_spill (store_info_t store_info, bitmap gen, bitmap kill) | |
2593 | { | |
2594 | while (store_info) | |
2595 | { | |
2596 | if (store_info->alias_set) | |
2597 | { | |
2598 | int index = get_bitmap_index (clear_alias_group, | |
2599 | store_info->alias_set); | |
2600 | if (index != 0) | |
2601 | { | |
2602 | bitmap_set_bit (gen, index); | |
2603 | if (kill) | |
2604 | bitmap_clear_bit (kill, index); | |
2605 | } | |
2606 | } | |
2607 | store_info = store_info->next; | |
2608 | } | |
2609 | } | |
2610 | ||
2611 | ||
2612 | /* Process the READ_INFOs into the bitmaps into GEN and KILL. KILL | |
2613 | may be NULL. */ | |
2614 | ||
2615 | static void | |
2616 | scan_reads_nospill (insn_info_t insn_info, bitmap gen, bitmap kill) | |
2617 | { | |
2618 | read_info_t read_info = insn_info->read_rec; | |
2619 | int i; | |
2620 | group_info_t group; | |
2621 | ||
64520bdc EB |
2622 | /* If this insn reads the frame, kill all the frame related stores. */ |
2623 | if (insn_info->frame_read) | |
2624 | { | |
2625 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) | |
2626 | if (group->process_globally && group->frame_related) | |
2627 | { | |
2628 | if (kill) | |
2629 | bitmap_ior_into (kill, group->group_kill); | |
2630 | bitmap_and_compl_into (gen, group->group_kill); | |
2631 | } | |
2632 | } | |
2633 | ||
6fb5fa3c DB |
2634 | while (read_info) |
2635 | { | |
2636 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) | |
2637 | { | |
2638 | if (group->process_globally) | |
2639 | { | |
2640 | if (i == read_info->group_id) | |
2641 | { | |
2642 | if (read_info->begin > read_info->end) | |
2643 | { | |
2644 | /* Begin > end for block mode reads. */ | |
2645 | if (kill) | |
2646 | bitmap_ior_into (kill, group->group_kill); | |
2647 | bitmap_and_compl_into (gen, group->group_kill); | |
2648 | } | |
2649 | else | |
2650 | { | |
2651 | /* The groups are the same, just process the | |
2652 | offsets. */ | |
2653 | HOST_WIDE_INT j; | |
2654 | for (j = read_info->begin; j < read_info->end; j++) | |
2655 | { | |
2656 | int index = get_bitmap_index (group, j); | |
2657 | if (index != 0) | |
2658 | { | |
2659 | if (kill) | |
2660 | bitmap_set_bit (kill, index); | |
2661 | bitmap_clear_bit (gen, index); | |
2662 | } | |
2663 | } | |
2664 | } | |
2665 | } | |
2666 | else | |
2667 | { | |
2668 | /* The groups are different, if the alias sets | |
2669 | conflict, clear the entire group. We only need | |
2670 | to apply this test if the read_info is a cselib | |
2671 | read. Anything with a constant base cannot alias | |
2672 | something else with a different constant | |
2673 | base. */ | |
2674 | if ((read_info->group_id < 0) | |
2675 | && canon_true_dependence (group->base_mem, | |
2676 | QImode, | |
2677 | group->canon_base_mem, | |
2678 | read_info->mem, rtx_varies_p)) | |
2679 | { | |
2680 | if (kill) | |
2681 | bitmap_ior_into (kill, group->group_kill); | |
2682 | bitmap_and_compl_into (gen, group->group_kill); | |
2683 | } | |
2684 | } | |
2685 | } | |
2686 | } | |
2687 | ||
2688 | read_info = read_info->next; | |
2689 | } | |
2690 | } | |
2691 | ||
2692 | /* Process the READ_INFOs into the bitmaps into GEN and KILL. KILL | |
2693 | may be NULL. */ | |
2694 | ||
2695 | static void | |
2696 | scan_reads_spill (read_info_t read_info, bitmap gen, bitmap kill) | |
2697 | { | |
2698 | while (read_info) | |
2699 | { | |
2700 | if (read_info->alias_set) | |
2701 | { | |
2702 | int index = get_bitmap_index (clear_alias_group, | |
2703 | read_info->alias_set); | |
2704 | if (index != 0) | |
2705 | { | |
2706 | if (kill) | |
2707 | bitmap_set_bit (kill, index); | |
2708 | bitmap_clear_bit (gen, index); | |
2709 | } | |
2710 | } | |
2711 | ||
2712 | read_info = read_info->next; | |
2713 | } | |
2714 | } | |
2715 | ||
2716 | ||
2717 | /* Return the insn in BB_INFO before the first wild read or if there | |
2718 | are no wild reads in the block, return the last insn. */ | |
2719 | ||
2720 | static insn_info_t | |
2721 | find_insn_before_first_wild_read (bb_info_t bb_info) | |
2722 | { | |
2723 | insn_info_t insn_info = bb_info->last_insn; | |
2724 | insn_info_t last_wild_read = NULL; | |
2725 | ||
2726 | while (insn_info) | |
2727 | { | |
2728 | if (insn_info->wild_read) | |
2729 | { | |
2730 | last_wild_read = insn_info->prev_insn; | |
2731 | /* Block starts with wild read. */ | |
2732 | if (!last_wild_read) | |
2733 | return NULL; | |
2734 | } | |
2735 | ||
2736 | insn_info = insn_info->prev_insn; | |
2737 | } | |
2738 | ||
2739 | if (last_wild_read) | |
2740 | return last_wild_read; | |
2741 | else | |
2742 | return bb_info->last_insn; | |
2743 | } | |
2744 | ||
2745 | ||
2746 | /* Scan the insns in BB_INFO starting at PTR and going to the top of | |
2747 | the block in order to build the gen and kill sets for the block. | |
2748 | We start at ptr which may be the last insn in the block or may be | |
2749 | the first insn with a wild read. In the latter case we are able to | |
2750 | skip the rest of the block because it just does not matter: | |
2751 | anything that happens is hidden by the wild read. */ | |
2752 | ||
2753 | static void | |
2754 | dse_step3_scan (bool for_spills, basic_block bb) | |
2755 | { | |
2756 | bb_info_t bb_info = bb_table[bb->index]; | |
2757 | insn_info_t insn_info; | |
2758 | ||
2759 | if (for_spills) | |
2760 | /* There are no wild reads in the spill case. */ | |
2761 | insn_info = bb_info->last_insn; | |
2762 | else | |
2763 | insn_info = find_insn_before_first_wild_read (bb_info); | |
2764 | ||
2765 | /* In the spill case or in the no_spill case if there is no wild | |
2766 | read in the block, we will need a kill set. */ | |
2767 | if (insn_info == bb_info->last_insn) | |
2768 | { | |
2769 | if (bb_info->kill) | |
2770 | bitmap_clear (bb_info->kill); | |
2771 | else | |
2772 | bb_info->kill = BITMAP_ALLOC (NULL); | |
2773 | } | |
2774 | else | |
2775 | if (bb_info->kill) | |
2776 | BITMAP_FREE (bb_info->kill); | |
2777 | ||
2778 | while (insn_info) | |
2779 | { | |
2780 | /* There may have been code deleted by the dce pass run before | |
2781 | this phase. */ | |
2782 | if (insn_info->insn && INSN_P (insn_info->insn)) | |
2783 | { | |
2784 | /* Process the read(s) last. */ | |
2785 | if (for_spills) | |
2786 | { | |
2787 | scan_stores_spill (insn_info->store_rec, bb_info->gen, bb_info->kill); | |
2788 | scan_reads_spill (insn_info->read_rec, bb_info->gen, bb_info->kill); | |
2789 | } | |
2790 | else | |
2791 | { | |
2792 | scan_stores_nospill (insn_info->store_rec, bb_info->gen, bb_info->kill); | |
2793 | scan_reads_nospill (insn_info, bb_info->gen, bb_info->kill); | |
2794 | } | |
2795 | } | |
2796 | ||
2797 | insn_info = insn_info->prev_insn; | |
2798 | } | |
2799 | } | |
2800 | ||
2801 | ||
2802 | /* Set the gen set of the exit block, and also any block with no | |
2803 | successors that does not have a wild read. */ | |
2804 | ||
2805 | static void | |
2806 | dse_step3_exit_block_scan (bb_info_t bb_info) | |
2807 | { | |
2808 | /* The gen set is all 0's for the exit block except for the | |
2809 | frame_pointer_group. */ | |
2810 | ||
2811 | if (stores_off_frame_dead_at_return) | |
2812 | { | |
2813 | unsigned int i; | |
2814 | group_info_t group; | |
2815 | ||
2816 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) | |
2817 | { | |
2818 | if (group->process_globally && group->frame_related) | |
2819 | bitmap_ior_into (bb_info->gen, group->group_kill); | |
2820 | } | |
2821 | } | |
2822 | } | |
2823 | ||
2824 | ||
2825 | /* Find all of the blocks that are not backwards reachable from the | |
2826 | exit block or any block with no successors (BB). These are the | |
2827 | infinite loops or infinite self loops. These blocks will still | |
2828 | have their bits set in UNREACHABLE_BLOCKS. */ | |
2829 | ||
2830 | static void | |
2831 | mark_reachable_blocks (sbitmap unreachable_blocks, basic_block bb) | |
2832 | { | |
2833 | edge e; | |
2834 | edge_iterator ei; | |
2835 | ||
2836 | if (TEST_BIT (unreachable_blocks, bb->index)) | |
2837 | { | |
2838 | RESET_BIT (unreachable_blocks, bb->index); | |
2839 | FOR_EACH_EDGE (e, ei, bb->preds) | |
2840 | { | |
2841 | mark_reachable_blocks (unreachable_blocks, e->src); | |
2842 | } | |
2843 | } | |
2844 | } | |
2845 | ||
2846 | /* Build the transfer functions for the function. */ | |
2847 | ||
2848 | static void | |
2849 | dse_step3 (bool for_spills) | |
2850 | { | |
2851 | basic_block bb; | |
2852 | sbitmap unreachable_blocks = sbitmap_alloc (last_basic_block); | |
2853 | sbitmap_iterator sbi; | |
2854 | bitmap all_ones = NULL; | |
2855 | unsigned int i; | |
2856 | ||
2857 | sbitmap_ones (unreachable_blocks); | |
2858 | ||
2859 | FOR_ALL_BB (bb) | |
2860 | { | |
2861 | bb_info_t bb_info = bb_table[bb->index]; | |
2862 | if (bb_info->gen) | |
2863 | bitmap_clear (bb_info->gen); | |
2864 | else | |
2865 | bb_info->gen = BITMAP_ALLOC (NULL); | |
2866 | ||
2867 | if (bb->index == ENTRY_BLOCK) | |
2868 | ; | |
2869 | else if (bb->index == EXIT_BLOCK) | |
2870 | dse_step3_exit_block_scan (bb_info); | |
2871 | else | |
2872 | dse_step3_scan (for_spills, bb); | |
2873 | if (EDGE_COUNT (bb->succs) == 0) | |
2874 | mark_reachable_blocks (unreachable_blocks, bb); | |
2875 | ||
2876 | /* If this is the second time dataflow is run, delete the old | |
2877 | sets. */ | |
2878 | if (bb_info->in) | |
2879 | BITMAP_FREE (bb_info->in); | |
2880 | if (bb_info->out) | |
2881 | BITMAP_FREE (bb_info->out); | |
2882 | } | |
2883 | ||
2884 | /* For any block in an infinite loop, we must initialize the out set | |
2885 | to all ones. This could be expensive, but almost never occurs in | |
2886 | practice. However, it is common in regression tests. */ | |
2887 | EXECUTE_IF_SET_IN_SBITMAP (unreachable_blocks, 0, i, sbi) | |
2888 | { | |
2889 | if (bitmap_bit_p (all_blocks, i)) | |
2890 | { | |
2891 | bb_info_t bb_info = bb_table[i]; | |
2892 | if (!all_ones) | |
2893 | { | |
2894 | unsigned int j; | |
2895 | group_info_t group; | |
2896 | ||
2897 | all_ones = BITMAP_ALLOC (NULL); | |
2898 | for (j = 0; VEC_iterate (group_info_t, rtx_group_vec, j, group); j++) | |
2899 | bitmap_ior_into (all_ones, group->group_kill); | |
2900 | } | |
2901 | if (!bb_info->out) | |
2902 | { | |
2903 | bb_info->out = BITMAP_ALLOC (NULL); | |
2904 | bitmap_copy (bb_info->out, all_ones); | |
2905 | } | |
2906 | } | |
2907 | } | |
2908 | ||
2909 | if (all_ones) | |
2910 | BITMAP_FREE (all_ones); | |
2911 | sbitmap_free (unreachable_blocks); | |
2912 | } | |
2913 | ||
2914 | ||
2915 | \f | |
2916 | /*---------------------------------------------------------------------------- | |
2917 | Fourth step. | |
2918 | ||
2919 | Solve the bitvector equations. | |
2920 | ----------------------------------------------------------------------------*/ | |
2921 | ||
2922 | ||
2923 | /* Confluence function for blocks with no successors. Create an out | |
2924 | set from the gen set of the exit block. This block logically has | |
2925 | the exit block as a successor. */ | |
2926 | ||
2927 | ||
2928 | ||
2929 | static void | |
2930 | dse_confluence_0 (basic_block bb) | |
2931 | { | |
2932 | bb_info_t bb_info = bb_table[bb->index]; | |
2933 | ||
2934 | if (bb->index == EXIT_BLOCK) | |
2935 | return; | |
2936 | ||
2937 | if (!bb_info->out) | |
2938 | { | |
2939 | bb_info->out = BITMAP_ALLOC (NULL); | |
2940 | bitmap_copy (bb_info->out, bb_table[EXIT_BLOCK]->gen); | |
2941 | } | |
2942 | } | |
2943 | ||
2944 | /* Propagate the information from the in set of the dest of E to the | |
2945 | out set of the src of E. If the various in or out sets are not | |
2946 | there, that means they are all ones. */ | |
2947 | ||
2948 | static void | |
2949 | dse_confluence_n (edge e) | |
2950 | { | |
2951 | bb_info_t src_info = bb_table[e->src->index]; | |
2952 | bb_info_t dest_info = bb_table[e->dest->index]; | |
2953 | ||
2954 | if (dest_info->in) | |
2955 | { | |
2956 | if (src_info->out) | |
2957 | bitmap_and_into (src_info->out, dest_info->in); | |
2958 | else | |
2959 | { | |
2960 | src_info->out = BITMAP_ALLOC (NULL); | |
2961 | bitmap_copy (src_info->out, dest_info->in); | |
2962 | } | |
2963 | } | |
2964 | } | |
2965 | ||
2966 | ||
2967 | /* Propagate the info from the out to the in set of BB_INDEX's basic | |
2968 | block. There are three cases: | |
2969 | ||
2970 | 1) The block has no kill set. In this case the kill set is all | |
2971 | ones. It does not matter what the out set of the block is, none of | |
2972 | the info can reach the top. The only thing that reaches the top is | |
2973 | the gen set and we just copy the set. | |
2974 | ||
2975 | 2) There is a kill set but no out set and bb has successors. In | |
2976 | this case we just return. Eventually an out set will be created and | |
2977 | it is better to wait than to create a set of ones. | |
2978 | ||
2979 | 3) There is both a kill and out set. We apply the obvious transfer | |
2980 | function. | |
2981 | */ | |
2982 | ||
2983 | static bool | |
2984 | dse_transfer_function (int bb_index) | |
2985 | { | |
2986 | bb_info_t bb_info = bb_table[bb_index]; | |
2987 | ||
2988 | if (bb_info->kill) | |
2989 | { | |
2990 | if (bb_info->out) | |
2991 | { | |
2992 | /* Case 3 above. */ | |
2993 | if (bb_info->in) | |
2994 | return bitmap_ior_and_compl (bb_info->in, bb_info->gen, | |
2995 | bb_info->out, bb_info->kill); | |
2996 | else | |
2997 | { | |
2998 | bb_info->in = BITMAP_ALLOC (NULL); | |
2999 | bitmap_ior_and_compl (bb_info->in, bb_info->gen, | |
3000 | bb_info->out, bb_info->kill); | |
3001 | return true; | |
3002 | } | |
3003 | } | |
3004 | else | |
3005 | /* Case 2 above. */ | |
3006 | return false; | |
3007 | } | |
3008 | else | |
3009 | { | |
3010 | /* Case 1 above. If there is already an in set, nothing | |
3011 | happens. */ | |
3012 | if (bb_info->in) | |
3013 | return false; | |
3014 | else | |
3015 | { | |
3016 | bb_info->in = BITMAP_ALLOC (NULL); | |
3017 | bitmap_copy (bb_info->in, bb_info->gen); | |
3018 | return true; | |
3019 | } | |
3020 | } | |
3021 | } | |
3022 | ||
3023 | /* Solve the dataflow equations. */ | |
3024 | ||
3025 | static void | |
3026 | dse_step4 (void) | |
3027 | { | |
3028 | df_simple_dataflow (DF_BACKWARD, NULL, dse_confluence_0, | |
3029 | dse_confluence_n, dse_transfer_function, | |
3030 | all_blocks, df_get_postorder (DF_BACKWARD), | |
3031 | df_get_n_blocks (DF_BACKWARD)); | |
3032 | if (dump_file) | |
3033 | { | |
3034 | basic_block bb; | |
3035 | ||
3036 | fprintf (dump_file, "\n\n*** Global dataflow info after analysis.\n"); | |
3037 | FOR_ALL_BB (bb) | |
3038 | { | |
3039 | bb_info_t bb_info = bb_table[bb->index]; | |
3040 | ||
3041 | df_print_bb_index (bb, dump_file); | |
3042 | if (bb_info->in) | |
3043 | bitmap_print (dump_file, bb_info->in, " in: ", "\n"); | |
3044 | else | |
3045 | fprintf (dump_file, " in: *MISSING*\n"); | |
3046 | if (bb_info->gen) | |
3047 | bitmap_print (dump_file, bb_info->gen, " gen: ", "\n"); | |
3048 | else | |
3049 | fprintf (dump_file, " gen: *MISSING*\n"); | |
3050 | if (bb_info->kill) | |
3051 | bitmap_print (dump_file, bb_info->kill, " kill: ", "\n"); | |
3052 | else | |
3053 | fprintf (dump_file, " kill: *MISSING*\n"); | |
3054 | if (bb_info->out) | |
3055 | bitmap_print (dump_file, bb_info->out, " out: ", "\n"); | |
3056 | else | |
3057 | fprintf (dump_file, " out: *MISSING*\n\n"); | |
3058 | } | |
3059 | } | |
3060 | } | |
3061 | ||
3062 | ||
3063 | \f | |
3064 | /*---------------------------------------------------------------------------- | |
3065 | Fifth step. | |
3066 | ||
0d52bcc1 | 3067 | Delete the stores that can only be deleted using the global information. |
6fb5fa3c DB |
3068 | ----------------------------------------------------------------------------*/ |
3069 | ||
3070 | ||
3071 | static void | |
3072 | dse_step5_nospill (void) | |
3073 | { | |
3074 | basic_block bb; | |
3075 | FOR_EACH_BB (bb) | |
3076 | { | |
3077 | bb_info_t bb_info = bb_table[bb->index]; | |
3078 | insn_info_t insn_info = bb_info->last_insn; | |
3079 | bitmap v = bb_info->out; | |
3080 | ||
3081 | while (insn_info) | |
3082 | { | |
3083 | bool deleted = false; | |
3084 | if (dump_file && insn_info->insn) | |
3085 | { | |
3086 | fprintf (dump_file, "starting to process insn %d\n", | |
3087 | INSN_UID (insn_info->insn)); | |
3088 | bitmap_print (dump_file, v, " v: ", "\n"); | |
3089 | } | |
3090 | ||
3091 | /* There may have been code deleted by the dce pass run before | |
3092 | this phase. */ | |
3093 | if (insn_info->insn | |
3094 | && INSN_P (insn_info->insn) | |
3095 | && (!insn_info->cannot_delete) | |
3096 | && (!bitmap_empty_p (v))) | |
3097 | { | |
3098 | store_info_t store_info = insn_info->store_rec; | |
3099 | ||
3100 | /* Try to delete the current insn. */ | |
3101 | deleted = true; | |
3102 | ||
3103 | /* Skip the clobbers. */ | |
3104 | while (!store_info->is_set) | |
3105 | store_info = store_info->next; | |
3106 | ||
3107 | if (store_info->alias_set) | |
3108 | deleted = false; | |
3109 | else | |
3110 | { | |
3111 | HOST_WIDE_INT i; | |
3112 | group_info_t group_info | |
3113 | = VEC_index (group_info_t, rtx_group_vec, store_info->group_id); | |
3114 | ||
3115 | for (i = store_info->begin; i < store_info->end; i++) | |
3116 | { | |
3117 | int index = get_bitmap_index (group_info, i); | |
3118 | ||
3119 | if (dump_file) | |
3120 | fprintf (dump_file, "i = %d, index = %d\n", (int)i, index); | |
3121 | if (index == 0 || !bitmap_bit_p (v, index)) | |
3122 | { | |
3123 | if (dump_file) | |
3124 | fprintf (dump_file, "failing at i = %d\n", (int)i); | |
3125 | deleted = false; | |
3126 | break; | |
3127 | } | |
3128 | } | |
3129 | } | |
3130 | if (deleted) | |
3131 | { | |
3132 | if (dbg_cnt (dse)) | |
3133 | { | |
3134 | check_for_inc_dec (insn_info->insn); | |
3135 | delete_insn (insn_info->insn); | |
3136 | insn_info->insn = NULL; | |
3137 | globally_deleted++; | |
3138 | } | |
3139 | } | |
3140 | } | |
3141 | /* We do want to process the local info if the insn was | |
6ed3da00 | 3142 | deleted. For instance, if the insn did a wild read, we |
6fb5fa3c DB |
3143 | no longer need to trash the info. */ |
3144 | if (insn_info->insn | |
3145 | && INSN_P (insn_info->insn) | |
3146 | && (!deleted)) | |
3147 | { | |
3148 | scan_stores_nospill (insn_info->store_rec, v, NULL); | |
3149 | if (insn_info->wild_read) | |
3150 | { | |
3151 | if (dump_file) | |
3152 | fprintf (dump_file, "wild read\n"); | |
3153 | bitmap_clear (v); | |
3154 | } | |
3155 | else if (insn_info->read_rec) | |
3156 | { | |
3157 | if (dump_file) | |
3158 | fprintf (dump_file, "regular read\n"); | |
3159 | scan_reads_nospill (insn_info, v, NULL); | |
3160 | } | |
3161 | } | |
3162 | ||
3163 | insn_info = insn_info->prev_insn; | |
3164 | } | |
3165 | } | |
3166 | } | |
3167 | ||
3168 | ||
3169 | static void | |
3170 | dse_step5_spill (void) | |
3171 | { | |
3172 | basic_block bb; | |
3173 | FOR_EACH_BB (bb) | |
3174 | { | |
3175 | bb_info_t bb_info = bb_table[bb->index]; | |
3176 | insn_info_t insn_info = bb_info->last_insn; | |
3177 | bitmap v = bb_info->out; | |
3178 | ||
3179 | while (insn_info) | |
3180 | { | |
3181 | bool deleted = false; | |
3182 | /* There may have been code deleted by the dce pass run before | |
3183 | this phase. */ | |
3184 | if (insn_info->insn | |
3185 | && INSN_P (insn_info->insn) | |
3186 | && (!insn_info->cannot_delete) | |
3187 | && (!bitmap_empty_p (v))) | |
3188 | { | |
3189 | /* Try to delete the current insn. */ | |
3190 | store_info_t store_info = insn_info->store_rec; | |
3191 | deleted = true; | |
3192 | ||
3193 | while (store_info) | |
3194 | { | |
3195 | if (store_info->alias_set) | |
3196 | { | |
3197 | int index = get_bitmap_index (clear_alias_group, | |
3198 | store_info->alias_set); | |
3199 | if (index == 0 || !bitmap_bit_p (v, index)) | |
3200 | { | |
3201 | deleted = false; | |
3202 | break; | |
3203 | } | |
3204 | } | |
3205 | else | |
3206 | deleted = false; | |
3207 | store_info = store_info->next; | |
3208 | } | |
3209 | if (deleted && dbg_cnt (dse)) | |
3210 | { | |
3211 | if (dump_file) | |
3212 | fprintf (dump_file, "Spill deleting insn %d\n", | |
3213 | INSN_UID (insn_info->insn)); | |
3214 | check_for_inc_dec (insn_info->insn); | |
3215 | delete_insn (insn_info->insn); | |
3216 | spill_deleted++; | |
3217 | insn_info->insn = NULL; | |
3218 | } | |
3219 | } | |
3220 | ||
3221 | if (insn_info->insn | |
3222 | && INSN_P (insn_info->insn) | |
3223 | && (!deleted)) | |
3224 | { | |
3225 | scan_stores_spill (insn_info->store_rec, v, NULL); | |
3226 | scan_reads_spill (insn_info->read_rec, v, NULL); | |
3227 | } | |
3228 | ||
3229 | insn_info = insn_info->prev_insn; | |
3230 | } | |
3231 | } | |
3232 | } | |
3233 | ||
3234 | ||
3235 | \f | |
3236 | /*---------------------------------------------------------------------------- | |
3237 | Sixth step. | |
3238 | ||
3239 | Destroy everything left standing. | |
3240 | ----------------------------------------------------------------------------*/ | |
3241 | ||
3242 | static void | |
3243 | dse_step6 (bool global_done) | |
3244 | { | |
3245 | unsigned int i; | |
3246 | group_info_t group; | |
3247 | basic_block bb; | |
3248 | ||
370f38e8 | 3249 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) |
6fb5fa3c | 3250 | { |
370f38e8 KZ |
3251 | free (group->offset_map_n); |
3252 | free (group->offset_map_p); | |
3253 | BITMAP_FREE (group->store1_n); | |
3254 | BITMAP_FREE (group->store1_p); | |
3255 | BITMAP_FREE (group->store2_n); | |
3256 | BITMAP_FREE (group->store2_p); | |
3257 | BITMAP_FREE (group->group_kill); | |
6fb5fa3c DB |
3258 | } |
3259 | ||
370f38e8 KZ |
3260 | if (global_done) |
3261 | FOR_ALL_BB (bb) | |
3262 | { | |
3263 | bb_info_t bb_info = bb_table[bb->index]; | |
3264 | BITMAP_FREE (bb_info->gen); | |
3265 | if (bb_info->kill) | |
3266 | BITMAP_FREE (bb_info->kill); | |
3267 | if (bb_info->in) | |
3268 | BITMAP_FREE (bb_info->in); | |
3269 | if (bb_info->out) | |
3270 | BITMAP_FREE (bb_info->out); | |
3271 | } | |
3272 | ||
6fb5fa3c DB |
3273 | if (clear_alias_sets) |
3274 | { | |
3275 | BITMAP_FREE (clear_alias_sets); | |
3276 | BITMAP_FREE (disqualified_clear_alias_sets); | |
3277 | free_alloc_pool (clear_alias_mode_pool); | |
3278 | htab_delete (clear_alias_mode_table); | |
3279 | } | |
3280 | ||
3281 | end_alias_analysis (); | |
3282 | free (bb_table); | |
3283 | htab_delete (rtx_group_table); | |
3284 | VEC_free (group_info_t, heap, rtx_group_vec); | |
3285 | BITMAP_FREE (all_blocks); | |
3286 | BITMAP_FREE (scratch); | |
3287 | ||
3288 | free_alloc_pool (rtx_store_info_pool); | |
3289 | free_alloc_pool (read_info_pool); | |
3290 | free_alloc_pool (insn_info_pool); | |
3291 | free_alloc_pool (bb_info_pool); | |
3292 | free_alloc_pool (rtx_group_info_pool); | |
3293 | free_alloc_pool (deferred_change_pool); | |
3294 | } | |
3295 | ||
3296 | ||
6fb5fa3c DB |
3297 | /* ------------------------------------------------------------------------- |
3298 | DSE | |
3299 | ------------------------------------------------------------------------- */ | |
3300 | ||
3301 | /* Callback for running pass_rtl_dse. */ | |
3302 | ||
3303 | static unsigned int | |
3304 | rest_of_handle_dse (void) | |
3305 | { | |
3306 | bool did_global = false; | |
3307 | ||
3308 | df_set_flags (DF_DEFER_INSN_RESCAN); | |
3309 | ||
02b47899 KZ |
3310 | /* Need the notes since we must track live hardregs in the forwards |
3311 | direction. */ | |
3312 | df_note_add_problem (); | |
3313 | df_analyze (); | |
3314 | ||
6fb5fa3c DB |
3315 | dse_step0 (); |
3316 | dse_step1 (); | |
3317 | dse_step2_init (); | |
3318 | if (dse_step2_nospill ()) | |
3319 | { | |
3320 | df_set_flags (DF_LR_RUN_DCE); | |
3321 | df_analyze (); | |
3322 | did_global = true; | |
3323 | if (dump_file) | |
3324 | fprintf (dump_file, "doing global processing\n"); | |
3325 | dse_step3 (false); | |
3326 | dse_step4 (); | |
3327 | dse_step5_nospill (); | |
3328 | } | |
3329 | ||
3330 | /* For the instance of dse that runs after reload, we make a special | |
3331 | pass to process the spills. These are special in that they are | |
3332 | totally transparent, i.e, there is no aliasing issues that need | |
3333 | to be considered. This means that the wild reads that kill | |
3334 | everything else do not apply here. */ | |
3335 | if (clear_alias_sets && dse_step2_spill ()) | |
3336 | { | |
3337 | if (!did_global) | |
3338 | { | |
3339 | df_set_flags (DF_LR_RUN_DCE); | |
3340 | df_analyze (); | |
3341 | } | |
3342 | did_global = true; | |
3343 | if (dump_file) | |
3344 | fprintf (dump_file, "doing global spill processing\n"); | |
3345 | dse_step3 (true); | |
3346 | dse_step4 (); | |
3347 | dse_step5_spill (); | |
3348 | } | |
3349 | ||
3350 | dse_step6 (did_global); | |
3351 | ||
3352 | if (dump_file) | |
3353 | fprintf (dump_file, "dse: local deletions = %d, global deletions = %d, spill deletions = %d\n", | |
3354 | locally_deleted, globally_deleted, spill_deleted); | |
3355 | return 0; | |
3356 | } | |
3357 | ||
3358 | static bool | |
3359 | gate_dse (void) | |
3360 | { | |
7d817ebc DE |
3361 | return gate_dse1 () || gate_dse2 (); |
3362 | } | |
3363 | ||
3364 | static bool | |
3365 | gate_dse1 (void) | |
3366 | { | |
3367 | return optimize > 0 && flag_dse | |
3368 | && dbg_cnt (dse1); | |
3369 | } | |
3370 | ||
3371 | static bool | |
3372 | gate_dse2 (void) | |
3373 | { | |
3374 | return optimize > 0 && flag_dse | |
3375 | && dbg_cnt (dse2); | |
6fb5fa3c DB |
3376 | } |
3377 | ||
8ddbbcae | 3378 | struct rtl_opt_pass pass_rtl_dse1 = |
6fb5fa3c | 3379 | { |
8ddbbcae JH |
3380 | { |
3381 | RTL_PASS, | |
6fb5fa3c | 3382 | "dse1", /* name */ |
7d817ebc | 3383 | gate_dse1, /* gate */ |
6fb5fa3c DB |
3384 | rest_of_handle_dse, /* execute */ |
3385 | NULL, /* sub */ | |
3386 | NULL, /* next */ | |
3387 | 0, /* static_pass_number */ | |
3388 | TV_DSE1, /* tv_id */ | |
3389 | 0, /* properties_required */ | |
3390 | 0, /* properties_provided */ | |
3391 | 0, /* properties_destroyed */ | |
3392 | 0, /* todo_flags_start */ | |
3393 | TODO_dump_func | | |
a36b8a1e | 3394 | TODO_df_finish | TODO_verify_rtl_sharing | |
8ddbbcae JH |
3395 | TODO_ggc_collect /* todo_flags_finish */ |
3396 | } | |
6fb5fa3c DB |
3397 | }; |
3398 | ||
8ddbbcae | 3399 | struct rtl_opt_pass pass_rtl_dse2 = |
6fb5fa3c | 3400 | { |
8ddbbcae JH |
3401 | { |
3402 | RTL_PASS, | |
6fb5fa3c | 3403 | "dse2", /* name */ |
7d817ebc | 3404 | gate_dse2, /* gate */ |
6fb5fa3c DB |
3405 | rest_of_handle_dse, /* execute */ |
3406 | NULL, /* sub */ | |
3407 | NULL, /* next */ | |
3408 | 0, /* static_pass_number */ | |
3409 | TV_DSE2, /* tv_id */ | |
3410 | 0, /* properties_required */ | |
3411 | 0, /* properties_provided */ | |
3412 | 0, /* properties_destroyed */ | |
3413 | 0, /* todo_flags_start */ | |
3414 | TODO_dump_func | | |
a36b8a1e | 3415 | TODO_df_finish | TODO_verify_rtl_sharing | |
8ddbbcae JH |
3416 | TODO_ggc_collect /* todo_flags_finish */ |
3417 | } | |
6fb5fa3c | 3418 | }; |