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3072d30e | 1 | /* RTL dead store elimination. |
f0b5f617 | 2 | Copyright (C) 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
3072d30e | 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 | |
8c4c00c1 | 11 | Software Foundation; either version 3, or (at your option) any later |
3072d30e | 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 | |
8c4c00c1 | 20 | along with GCC; see the file COPYING3. If not see |
21 | <http://www.gnu.org/licenses/>. */ | |
3072d30e | 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" | |
10d4de0e | 32 | #include "tm_p.h" |
3072d30e | 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" | |
5c9051a4 | 46 | #include "optabs.h" |
3072d30e | 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 | |
bef304b8 | 100 | forwards ordering is to accommodate cselib. |
3072d30e | 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 | |
6dfdc153 | 148 | reference to r100. Most of the information is available to add this |
3072d30e | 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 | |
bef304b8 | 187 | required is to have those passes make the same calls that reload |
3072d30e | 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. */ | |
32c2fdea | 223 | alias_set_type alias_set; |
3072d30e | 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. */ | |
4e43e20a | 232 | unsigned HOST_WIDE_INT positions_needed; |
3072d30e | 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 | ||
4e43e20a | 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 | ||
3072d30e | 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. */ | |
32c2fdea | 264 | alias_set_type alias_set; |
3072d30e | 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 | ||
17e1318c | 297 | /* This field is only used for the processing of const functions. |
298 | These functions cannot read memory, but they can read the stack | |
16bf64db | 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. */ | |
17e1318c | 319 | bool stack_pointer_based; |
3072d30e | 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 | |
6dfdc153 | 333 | order to provide info to delete other insns. */ |
3072d30e | 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 | |
f0b5f617 | 348 | time it is guaranteed to be correct is when the traversal starts |
3072d30e | 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 | ||
377 | /* The set of store positions that exist in this block before a wild read. */ | |
378 | bitmap gen; | |
379 | ||
380 | /* The set of load positions that exist in this block above the | |
381 | same position of a store. */ | |
382 | bitmap kill; | |
383 | ||
384 | /* The set of stores that reach the top of the block without being | |
385 | killed by a read. | |
386 | ||
387 | Do not represent the in if it is all ones. Note that this is | |
388 | what the bitvector should logically be initialized to for a set | |
389 | intersection problem. However, like the kill set, this is too | |
390 | expensive. So initially, the in set will only be created for the | |
391 | exit block and any block that contains a wild read. */ | |
392 | bitmap in; | |
393 | ||
394 | /* The set of stores that reach the bottom of the block from it's | |
395 | successors. | |
396 | ||
397 | Do not represent the in if it is all ones. Note that this is | |
398 | what the bitvector should logically be initialized to for a set | |
399 | intersection problem. However, like the kill and in set, this is | |
400 | too expensive. So what is done is that the confluence operator | |
401 | just initializes the vector from one of the out sets of the | |
402 | successors of the block. */ | |
403 | bitmap out; | |
404 | }; | |
405 | ||
406 | typedef struct bb_info *bb_info_t; | |
407 | static alloc_pool bb_info_pool; | |
408 | ||
409 | /* Table to hold all bb_infos. */ | |
410 | static bb_info_t *bb_table; | |
411 | ||
412 | /* There is a group_info for each rtx base that is used to reference | |
413 | memory. There are also not many of the rtx bases because they are | |
414 | very limited in scope. */ | |
415 | ||
416 | struct group_info | |
417 | { | |
418 | /* The actual base of the address. */ | |
419 | rtx rtx_base; | |
420 | ||
421 | /* The sequential id of the base. This allows us to have a | |
422 | canonical ordering of these that is not based on addresses. */ | |
423 | int id; | |
424 | ||
425 | /* A mem wrapped around the base pointer for the group in order to | |
426 | do read dependency. */ | |
427 | rtx base_mem; | |
428 | ||
429 | /* Canonized version of base_mem, most likely the same thing. */ | |
430 | rtx canon_base_mem; | |
431 | ||
432 | /* These two sets of two bitmaps are used to keep track of how many | |
6dfdc153 | 433 | stores are actually referencing that position from this base. We |
3072d30e | 434 | only do this for rtx bases as this will be used to assign |
6dfdc153 | 435 | positions in the bitmaps for the global problem. Bit N is set in |
3072d30e | 436 | store1 on the first store for offset N. Bit N is set in store2 |
437 | for the second store to offset N. This is all we need since we | |
438 | only care about offsets that have two or more stores for them. | |
439 | ||
440 | The "_n" suffix is for offsets less than 0 and the "_p" suffix is | |
441 | for 0 and greater offsets. | |
442 | ||
443 | There is one special case here, for stores into the stack frame, | |
444 | we will or store1 into store2 before deciding which stores look | |
445 | at globally. This is because stores to the stack frame that have | |
446 | no other reads before the end of the function can also be | |
447 | deleted. */ | |
448 | bitmap store1_n, store1_p, store2_n, store2_p; | |
449 | ||
6dfdc153 | 450 | /* The positions in this bitmap have the same assignments as the in, |
3072d30e | 451 | out, gen and kill bitmaps. This bitmap is all zeros except for |
6dfdc153 | 452 | the positions that are occupied by stores for this group. */ |
3072d30e | 453 | bitmap group_kill; |
454 | ||
455 | /* True if there are any positions that are to be processed | |
456 | globally. */ | |
457 | bool process_globally; | |
458 | ||
459 | /* True if the base of this group is either the frame_pointer or | |
460 | hard_frame_pointer. */ | |
461 | bool frame_related; | |
462 | ||
463 | /* The offset_map is used to map the offsets from this base into | |
6dfdc153 | 464 | positions in the global bitmaps. It is only created after all of |
3072d30e | 465 | the all of stores have been scanned and we know which ones we |
466 | care about. */ | |
467 | int *offset_map_n, *offset_map_p; | |
468 | int offset_map_size_n, offset_map_size_p; | |
469 | }; | |
470 | typedef struct group_info *group_info_t; | |
c1fdef8e | 471 | typedef const struct group_info *const_group_info_t; |
3072d30e | 472 | static alloc_pool rtx_group_info_pool; |
473 | ||
474 | /* Tables of group_info structures, hashed by base value. */ | |
475 | static htab_t rtx_group_table; | |
476 | ||
477 | /* Index into the rtx_group_vec. */ | |
478 | static int rtx_group_next_id; | |
479 | ||
480 | DEF_VEC_P(group_info_t); | |
481 | DEF_VEC_ALLOC_P(group_info_t,heap); | |
482 | ||
483 | static VEC(group_info_t,heap) *rtx_group_vec; | |
484 | ||
485 | ||
486 | /* This structure holds the set of changes that are being deferred | |
487 | when removing read operation. See replace_read. */ | |
488 | struct deferred_change | |
489 | { | |
490 | ||
491 | /* The mem that is being replaced. */ | |
492 | rtx *loc; | |
493 | ||
494 | /* The reg it is being replaced with. */ | |
495 | rtx reg; | |
496 | ||
497 | struct deferred_change *next; | |
498 | }; | |
499 | ||
500 | typedef struct deferred_change *deferred_change_t; | |
501 | static alloc_pool deferred_change_pool; | |
502 | ||
503 | static deferred_change_t deferred_change_list = NULL; | |
504 | ||
505 | /* This are used to hold the alias sets of spill variables. Since | |
506 | these are never aliased and there may be a lot of them, it makes | |
507 | sense to treat them specially. This bitvector is only allocated in | |
508 | calls from dse_record_singleton_alias_set which currently is only | |
509 | made during reload1. So when dse is called before reload this | |
510 | mechanism does nothing. */ | |
511 | ||
512 | static bitmap clear_alias_sets = NULL; | |
513 | ||
514 | /* The set of clear_alias_sets that have been disqualified because | |
515 | there are loads or stores using a different mode than the alias set | |
516 | was registered with. */ | |
517 | static bitmap disqualified_clear_alias_sets = NULL; | |
518 | ||
519 | /* The group that holds all of the clear_alias_sets. */ | |
520 | static group_info_t clear_alias_group; | |
521 | ||
522 | /* The modes of the clear_alias_sets. */ | |
523 | static htab_t clear_alias_mode_table; | |
524 | ||
525 | /* Hash table element to look up the mode for an alias set. */ | |
526 | struct clear_alias_mode_holder | |
527 | { | |
32c2fdea | 528 | alias_set_type alias_set; |
3072d30e | 529 | enum machine_mode mode; |
530 | }; | |
531 | ||
532 | static alloc_pool clear_alias_mode_pool; | |
533 | ||
18d50ae6 | 534 | /* This is true except if cfun->stdarg -- i.e. we cannot do |
ff3ae375 | 535 | this for vararg functions because they play games with the frame. */ |
3072d30e | 536 | static bool stores_off_frame_dead_at_return; |
537 | ||
538 | /* Counter for stats. */ | |
539 | static int globally_deleted; | |
540 | static int locally_deleted; | |
541 | static int spill_deleted; | |
542 | ||
543 | static bitmap all_blocks; | |
544 | ||
545 | /* The number of bits used in the global bitmaps. */ | |
546 | static unsigned int current_position; | |
547 | ||
548 | ||
549 | static bool gate_dse (void); | |
4ff06051 | 550 | static bool gate_dse1 (void); |
551 | static bool gate_dse2 (void); | |
3072d30e | 552 | |
553 | \f | |
554 | /*---------------------------------------------------------------------------- | |
555 | Zeroth step. | |
556 | ||
557 | Initialization. | |
558 | ----------------------------------------------------------------------------*/ | |
559 | ||
560 | /* Hashtable callbacks for maintaining the "bases" field of | |
561 | store_group_info, given that the addresses are function invariants. */ | |
562 | ||
563 | static int | |
564 | clear_alias_mode_eq (const void *p1, const void *p2) | |
565 | { | |
566 | const struct clear_alias_mode_holder * h1 | |
567 | = (const struct clear_alias_mode_holder *) p1; | |
568 | const struct clear_alias_mode_holder * h2 | |
569 | = (const struct clear_alias_mode_holder *) p2; | |
570 | return h1->alias_set == h2->alias_set; | |
571 | } | |
572 | ||
573 | ||
574 | static hashval_t | |
575 | clear_alias_mode_hash (const void *p) | |
576 | { | |
577 | const struct clear_alias_mode_holder *holder | |
578 | = (const struct clear_alias_mode_holder *) p; | |
579 | return holder->alias_set; | |
580 | } | |
581 | ||
582 | ||
583 | /* Find the entry associated with ALIAS_SET. */ | |
584 | ||
585 | static struct clear_alias_mode_holder * | |
32c2fdea | 586 | clear_alias_set_lookup (alias_set_type alias_set) |
3072d30e | 587 | { |
588 | struct clear_alias_mode_holder tmp_holder; | |
589 | void **slot; | |
590 | ||
591 | tmp_holder.alias_set = alias_set; | |
592 | slot = htab_find_slot (clear_alias_mode_table, &tmp_holder, NO_INSERT); | |
593 | gcc_assert (*slot); | |
594 | ||
364c0c59 | 595 | return (struct clear_alias_mode_holder *) *slot; |
3072d30e | 596 | } |
597 | ||
598 | ||
599 | /* Hashtable callbacks for maintaining the "bases" field of | |
600 | store_group_info, given that the addresses are function invariants. */ | |
601 | ||
602 | static int | |
603 | invariant_group_base_eq (const void *p1, const void *p2) | |
604 | { | |
c1fdef8e | 605 | const_group_info_t gi1 = (const_group_info_t) p1; |
606 | const_group_info_t gi2 = (const_group_info_t) p2; | |
3072d30e | 607 | return rtx_equal_p (gi1->rtx_base, gi2->rtx_base); |
608 | } | |
609 | ||
610 | ||
611 | static hashval_t | |
612 | invariant_group_base_hash (const void *p) | |
613 | { | |
c1fdef8e | 614 | const_group_info_t gi = (const_group_info_t) p; |
3072d30e | 615 | int do_not_record; |
616 | return hash_rtx (gi->rtx_base, Pmode, &do_not_record, NULL, false); | |
617 | } | |
618 | ||
619 | ||
620 | /* Get the GROUP for BASE. Add a new group if it is not there. */ | |
621 | ||
622 | static group_info_t | |
623 | get_group_info (rtx base) | |
624 | { | |
625 | struct group_info tmp_gi; | |
626 | group_info_t gi; | |
627 | void **slot; | |
628 | ||
629 | if (base) | |
630 | { | |
631 | /* Find the store_base_info structure for BASE, creating a new one | |
632 | if necessary. */ | |
633 | tmp_gi.rtx_base = base; | |
634 | slot = htab_find_slot (rtx_group_table, &tmp_gi, INSERT); | |
635 | gi = (group_info_t) *slot; | |
636 | } | |
637 | else | |
638 | { | |
639 | if (!clear_alias_group) | |
640 | { | |
364c0c59 | 641 | clear_alias_group = gi = |
642 | (group_info_t) pool_alloc (rtx_group_info_pool); | |
3072d30e | 643 | memset (gi, 0, sizeof (struct group_info)); |
644 | gi->id = rtx_group_next_id++; | |
645 | gi->store1_n = BITMAP_ALLOC (NULL); | |
646 | gi->store1_p = BITMAP_ALLOC (NULL); | |
647 | gi->store2_n = BITMAP_ALLOC (NULL); | |
648 | gi->store2_p = BITMAP_ALLOC (NULL); | |
649 | gi->group_kill = BITMAP_ALLOC (NULL); | |
650 | gi->process_globally = false; | |
651 | gi->offset_map_size_n = 0; | |
652 | gi->offset_map_size_p = 0; | |
653 | gi->offset_map_n = NULL; | |
654 | gi->offset_map_p = NULL; | |
655 | VEC_safe_push (group_info_t, heap, rtx_group_vec, gi); | |
656 | } | |
657 | return clear_alias_group; | |
658 | } | |
659 | ||
660 | if (gi == NULL) | |
661 | { | |
364c0c59 | 662 | *slot = gi = (group_info_t) pool_alloc (rtx_group_info_pool); |
3072d30e | 663 | gi->rtx_base = base; |
664 | gi->id = rtx_group_next_id++; | |
665 | gi->base_mem = gen_rtx_MEM (QImode, base); | |
666 | gi->canon_base_mem = canon_rtx (gi->base_mem); | |
667 | gi->store1_n = BITMAP_ALLOC (NULL); | |
668 | gi->store1_p = BITMAP_ALLOC (NULL); | |
669 | gi->store2_n = BITMAP_ALLOC (NULL); | |
670 | gi->store2_p = BITMAP_ALLOC (NULL); | |
671 | gi->group_kill = BITMAP_ALLOC (NULL); | |
672 | gi->process_globally = false; | |
673 | gi->frame_related = | |
674 | (base == frame_pointer_rtx) || (base == hard_frame_pointer_rtx); | |
675 | gi->offset_map_size_n = 0; | |
676 | gi->offset_map_size_p = 0; | |
677 | gi->offset_map_n = NULL; | |
678 | gi->offset_map_p = NULL; | |
679 | VEC_safe_push (group_info_t, heap, rtx_group_vec, gi); | |
680 | } | |
681 | ||
682 | return gi; | |
683 | } | |
684 | ||
685 | ||
686 | /* Initialization of data structures. */ | |
687 | ||
688 | static void | |
689 | dse_step0 (void) | |
690 | { | |
691 | locally_deleted = 0; | |
692 | globally_deleted = 0; | |
693 | spill_deleted = 0; | |
694 | ||
695 | scratch = BITMAP_ALLOC (NULL); | |
696 | ||
697 | rtx_store_info_pool | |
698 | = create_alloc_pool ("rtx_store_info_pool", | |
699 | sizeof (struct store_info), 100); | |
700 | read_info_pool | |
701 | = create_alloc_pool ("read_info_pool", | |
702 | sizeof (struct read_info), 100); | |
703 | insn_info_pool | |
704 | = create_alloc_pool ("insn_info_pool", | |
705 | sizeof (struct insn_info), 100); | |
706 | bb_info_pool | |
707 | = create_alloc_pool ("bb_info_pool", | |
708 | sizeof (struct bb_info), 100); | |
709 | rtx_group_info_pool | |
710 | = create_alloc_pool ("rtx_group_info_pool", | |
711 | sizeof (struct group_info), 100); | |
712 | deferred_change_pool | |
713 | = create_alloc_pool ("deferred_change_pool", | |
714 | sizeof (struct deferred_change), 10); | |
715 | ||
716 | rtx_group_table = htab_create (11, invariant_group_base_hash, | |
717 | invariant_group_base_eq, NULL); | |
718 | ||
719 | bb_table = XCNEWVEC (bb_info_t, last_basic_block); | |
720 | rtx_group_next_id = 0; | |
721 | ||
18d50ae6 | 722 | stores_off_frame_dead_at_return = !cfun->stdarg; |
3072d30e | 723 | |
724 | init_alias_analysis (); | |
725 | ||
726 | if (clear_alias_sets) | |
727 | clear_alias_group = get_group_info (NULL); | |
728 | else | |
729 | clear_alias_group = NULL; | |
730 | } | |
731 | ||
732 | ||
733 | \f | |
734 | /*---------------------------------------------------------------------------- | |
735 | First step. | |
736 | ||
737 | Scan all of the insns. Any random ordering of the blocks is fine. | |
bef304b8 | 738 | Each block is scanned in forward order to accommodate cselib which |
3072d30e | 739 | is used to remove stores with non-constant bases. |
740 | ----------------------------------------------------------------------------*/ | |
741 | ||
742 | /* Delete all of the store_info recs from INSN_INFO. */ | |
743 | ||
744 | static void | |
745 | free_store_info (insn_info_t insn_info) | |
746 | { | |
747 | store_info_t store_info = insn_info->store_rec; | |
748 | while (store_info) | |
749 | { | |
750 | store_info_t next = store_info->next; | |
751 | if (store_info->cse_base) | |
752 | pool_free (cse_store_info_pool, store_info); | |
753 | else | |
754 | pool_free (rtx_store_info_pool, store_info); | |
755 | store_info = next; | |
756 | } | |
757 | ||
758 | insn_info->cannot_delete = true; | |
759 | insn_info->contains_cselib_groups = false; | |
760 | insn_info->store_rec = NULL; | |
761 | } | |
762 | ||
763 | ||
764 | struct insn_size { | |
765 | int size; | |
766 | rtx insn; | |
767 | }; | |
768 | ||
769 | ||
770 | /* Add an insn to do the add inside a x if it is a | |
771 | PRE/POST-INC/DEC/MODIFY. D is an structure containing the insn and | |
772 | the size of the mode of the MEM that this is inside of. */ | |
773 | ||
774 | static int | |
775 | replace_inc_dec (rtx *r, void *d) | |
776 | { | |
777 | rtx x = *r; | |
778 | struct insn_size *data = (struct insn_size *)d; | |
779 | switch (GET_CODE (x)) | |
780 | { | |
781 | case PRE_INC: | |
782 | case POST_INC: | |
783 | { | |
784 | rtx r1 = XEXP (x, 0); | |
785 | rtx c = gen_int_mode (Pmode, data->size); | |
786 | add_insn_before (data->insn, | |
787 | gen_rtx_SET (Pmode, r1, | |
788 | gen_rtx_PLUS (Pmode, r1, c)), | |
789 | NULL); | |
790 | return -1; | |
791 | } | |
792 | ||
793 | case PRE_DEC: | |
794 | case POST_DEC: | |
795 | { | |
796 | rtx r1 = XEXP (x, 0); | |
797 | rtx c = gen_int_mode (Pmode, -data->size); | |
798 | add_insn_before (data->insn, | |
799 | gen_rtx_SET (Pmode, r1, | |
800 | gen_rtx_PLUS (Pmode, r1, c)), | |
801 | NULL); | |
802 | return -1; | |
803 | } | |
804 | ||
805 | case PRE_MODIFY: | |
806 | case POST_MODIFY: | |
807 | { | |
bef304b8 | 808 | /* We can reuse the add because we are about to delete the |
3072d30e | 809 | insn that contained it. */ |
810 | rtx add = XEXP (x, 0); | |
811 | rtx r1 = XEXP (add, 0); | |
812 | add_insn_before (data->insn, | |
813 | gen_rtx_SET (Pmode, r1, add), NULL); | |
814 | return -1; | |
815 | } | |
816 | ||
817 | default: | |
818 | return 0; | |
819 | } | |
820 | } | |
821 | ||
822 | ||
823 | /* If X is a MEM, check the address to see if it is PRE/POST-INC/DEC/MODIFY | |
824 | and generate an add to replace that. */ | |
825 | ||
826 | static int | |
827 | replace_inc_dec_mem (rtx *r, void *d) | |
828 | { | |
829 | rtx x = *r; | |
830 | if (GET_CODE (x) == MEM) | |
831 | { | |
832 | struct insn_size data; | |
833 | ||
834 | data.size = GET_MODE_SIZE (GET_MODE (x)); | |
835 | data.insn = (rtx)d; | |
836 | ||
837 | for_each_rtx (&XEXP (x, 0), replace_inc_dec, &data); | |
838 | ||
839 | return -1; | |
840 | } | |
841 | return 0; | |
842 | } | |
843 | ||
844 | /* Before we delete INSN, make sure that the auto inc/dec, if it is | |
845 | there, is split into a separate insn. */ | |
846 | ||
847 | static void | |
848 | check_for_inc_dec (rtx insn) | |
849 | { | |
850 | rtx note = find_reg_note (insn, REG_INC, NULL_RTX); | |
851 | if (note) | |
852 | for_each_rtx (&insn, replace_inc_dec_mem, insn); | |
853 | } | |
854 | ||
855 | ||
856 | /* Delete the insn and free all of the fields inside INSN_INFO. */ | |
857 | ||
858 | static void | |
859 | delete_dead_store_insn (insn_info_t insn_info) | |
860 | { | |
861 | read_info_t read_info; | |
862 | ||
863 | if (!dbg_cnt (dse)) | |
864 | return; | |
865 | ||
866 | check_for_inc_dec (insn_info->insn); | |
867 | if (dump_file) | |
868 | { | |
869 | fprintf (dump_file, "Locally deleting insn %d ", | |
870 | INSN_UID (insn_info->insn)); | |
871 | if (insn_info->store_rec->alias_set) | |
872 | fprintf (dump_file, "alias set %d\n", | |
32c2fdea | 873 | (int) insn_info->store_rec->alias_set); |
3072d30e | 874 | else |
875 | fprintf (dump_file, "\n"); | |
876 | } | |
877 | ||
878 | free_store_info (insn_info); | |
879 | read_info = insn_info->read_rec; | |
880 | ||
881 | while (read_info) | |
882 | { | |
883 | read_info_t next = read_info->next; | |
884 | pool_free (read_info_pool, read_info); | |
885 | read_info = next; | |
886 | } | |
887 | insn_info->read_rec = NULL; | |
888 | ||
889 | delete_insn (insn_info->insn); | |
890 | locally_deleted++; | |
891 | insn_info->insn = NULL; | |
892 | ||
893 | insn_info->wild_read = false; | |
894 | } | |
895 | ||
896 | ||
897 | /* Set the store* bitmaps offset_map_size* fields in GROUP based on | |
898 | OFFSET and WIDTH. */ | |
899 | ||
900 | static void | |
901 | set_usage_bits (group_info_t group, HOST_WIDE_INT offset, HOST_WIDE_INT width) | |
902 | { | |
903 | HOST_WIDE_INT i; | |
904 | ||
905 | if ((offset > -MAX_OFFSET) && (offset < MAX_OFFSET)) | |
906 | for (i=offset; i<offset+width; i++) | |
907 | { | |
908 | bitmap store1; | |
909 | bitmap store2; | |
910 | int ai; | |
911 | if (i < 0) | |
912 | { | |
913 | store1 = group->store1_n; | |
914 | store2 = group->store2_n; | |
915 | ai = -i; | |
916 | } | |
917 | else | |
918 | { | |
919 | store1 = group->store1_p; | |
920 | store2 = group->store2_p; | |
921 | ai = i; | |
922 | } | |
923 | ||
924 | if (bitmap_bit_p (store1, ai)) | |
925 | bitmap_set_bit (store2, ai); | |
926 | else | |
927 | { | |
928 | bitmap_set_bit (store1, ai); | |
929 | if (i < 0) | |
930 | { | |
931 | if (group->offset_map_size_n < ai) | |
932 | group->offset_map_size_n = ai; | |
933 | } | |
934 | else | |
935 | { | |
936 | if (group->offset_map_size_p < ai) | |
937 | group->offset_map_size_p = ai; | |
938 | } | |
939 | } | |
940 | } | |
941 | } | |
942 | ||
943 | ||
944 | /* Set the BB_INFO so that the last insn is marked as a wild read. */ | |
945 | ||
946 | static void | |
947 | add_wild_read (bb_info_t bb_info) | |
948 | { | |
949 | insn_info_t insn_info = bb_info->last_insn; | |
950 | read_info_t *ptr = &insn_info->read_rec; | |
951 | ||
952 | while (*ptr) | |
953 | { | |
954 | read_info_t next = (*ptr)->next; | |
32c2fdea | 955 | if ((*ptr)->alias_set == 0) |
3072d30e | 956 | { |
957 | pool_free (read_info_pool, *ptr); | |
958 | *ptr = next; | |
959 | } | |
960 | else | |
961 | ptr = &(*ptr)->next; | |
962 | } | |
963 | insn_info->wild_read = true; | |
964 | active_local_stores = NULL; | |
965 | } | |
966 | ||
967 | ||
17e1318c | 968 | /* Return true if X is a constant or one of the registers that behave |
969 | as a constant over the life of a function. This is equivalent to | |
970 | !rtx_varies_p for memory addresses. */ | |
3072d30e | 971 | |
972 | static bool | |
973 | const_or_frame_p (rtx x) | |
974 | { | |
975 | switch (GET_CODE (x)) | |
976 | { | |
977 | case MEM: | |
978 | return MEM_READONLY_P (x); | |
979 | ||
980 | case CONST: | |
981 | case CONST_INT: | |
982 | case CONST_DOUBLE: | |
983 | case CONST_VECTOR: | |
984 | case SYMBOL_REF: | |
985 | case LABEL_REF: | |
986 | return true; | |
987 | ||
988 | case REG: | |
989 | /* Note that we have to test for the actual rtx used for the frame | |
990 | and arg pointers and not just the register number in case we have | |
991 | eliminated the frame and/or arg pointer and are using it | |
992 | for pseudos. */ | |
993 | if (x == frame_pointer_rtx || x == hard_frame_pointer_rtx | |
994 | /* The arg pointer varies if it is not a fixed register. */ | |
995 | || (x == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]) | |
996 | || x == pic_offset_table_rtx) | |
997 | return true; | |
998 | return false; | |
999 | ||
1000 | default: | |
1001 | return false; | |
1002 | } | |
1003 | } | |
1004 | ||
1005 | /* Take all reasonable action to put the address of MEM into the form | |
1006 | that we can do analysis on. | |
1007 | ||
1008 | The gold standard is to get the address into the form: address + | |
1009 | OFFSET where address is something that rtx_varies_p considers a | |
1010 | constant. When we can get the address in this form, we can do | |
1011 | global analysis on it. Note that for constant bases, address is | |
1012 | not actually returned, only the group_id. The address can be | |
1013 | obtained from that. | |
1014 | ||
1015 | If that fails, we try cselib to get a value we can at least use | |
1016 | locally. If that fails we return false. | |
1017 | ||
1018 | The GROUP_ID is set to -1 for cselib bases and the index of the | |
1019 | group for non_varying bases. | |
1020 | ||
1021 | FOR_READ is true if this is a mem read and false if not. */ | |
1022 | ||
1023 | static bool | |
1024 | canon_address (rtx mem, | |
32c2fdea | 1025 | alias_set_type *alias_set_out, |
3072d30e | 1026 | int *group_id, |
1027 | HOST_WIDE_INT *offset, | |
1028 | cselib_val **base) | |
1029 | { | |
1030 | rtx mem_address = XEXP (mem, 0); | |
1031 | rtx expanded_address, address; | |
1032 | /* Make sure that cselib is has initialized all of the operands of | |
1033 | the address before asking it to do the subst. */ | |
1034 | ||
1035 | if (clear_alias_sets) | |
1036 | { | |
1037 | /* If this is a spill, do not do any further processing. */ | |
32c2fdea | 1038 | alias_set_type alias_set = MEM_ALIAS_SET (mem); |
3072d30e | 1039 | if (dump_file) |
32c2fdea | 1040 | fprintf (dump_file, "found alias set %d\n", (int) alias_set); |
3072d30e | 1041 | if (bitmap_bit_p (clear_alias_sets, alias_set)) |
1042 | { | |
1043 | struct clear_alias_mode_holder *entry | |
1044 | = clear_alias_set_lookup (alias_set); | |
1045 | ||
1046 | /* If the modes do not match, we cannot process this set. */ | |
1047 | if (entry->mode != GET_MODE (mem)) | |
1048 | { | |
1049 | if (dump_file) | |
1050 | fprintf (dump_file, | |
1051 | "disqualifying alias set %d, (%s) != (%s)\n", | |
32c2fdea | 1052 | (int) alias_set, GET_MODE_NAME (entry->mode), |
3072d30e | 1053 | GET_MODE_NAME (GET_MODE (mem))); |
1054 | ||
1055 | bitmap_set_bit (disqualified_clear_alias_sets, alias_set); | |
1056 | return false; | |
1057 | } | |
1058 | ||
1059 | *alias_set_out = alias_set; | |
1060 | *group_id = clear_alias_group->id; | |
1061 | return true; | |
1062 | } | |
1063 | } | |
1064 | ||
1065 | *alias_set_out = 0; | |
1066 | ||
1067 | cselib_lookup (mem_address, Pmode, 1); | |
1068 | ||
1069 | if (dump_file) | |
1070 | { | |
1071 | fprintf (dump_file, " mem: "); | |
1072 | print_inline_rtx (dump_file, mem_address, 0); | |
1073 | fprintf (dump_file, "\n"); | |
1074 | } | |
1075 | ||
1076 | /* Use cselib to replace all of the reg references with the full | |
1077 | expression. This will take care of the case where we have | |
1078 | ||
1079 | r_x = base + offset; | |
1080 | val = *r_x; | |
1081 | ||
1082 | by making it into | |
1083 | ||
1084 | val = *(base + offset); | |
1085 | */ | |
1086 | ||
1087 | expanded_address = cselib_expand_value_rtx (mem_address, scratch, 5); | |
1088 | ||
1089 | /* If this fails, just go with the mem_address. */ | |
1090 | if (!expanded_address) | |
1091 | expanded_address = mem_address; | |
1092 | ||
1093 | /* Split the address into canonical BASE + OFFSET terms. */ | |
1094 | address = canon_rtx (expanded_address); | |
1095 | ||
1096 | *offset = 0; | |
1097 | ||
1098 | if (dump_file) | |
1099 | { | |
1100 | fprintf (dump_file, "\n after cselib_expand address: "); | |
1101 | print_inline_rtx (dump_file, expanded_address, 0); | |
1102 | fprintf (dump_file, "\n"); | |
1103 | ||
1104 | fprintf (dump_file, "\n after canon_rtx address: "); | |
1105 | print_inline_rtx (dump_file, address, 0); | |
1106 | fprintf (dump_file, "\n"); | |
1107 | } | |
1108 | ||
1109 | if (GET_CODE (address) == CONST) | |
1110 | address = XEXP (address, 0); | |
1111 | ||
1112 | if (GET_CODE (address) == PLUS && GET_CODE (XEXP (address, 1)) == CONST_INT) | |
1113 | { | |
1114 | *offset = INTVAL (XEXP (address, 1)); | |
1115 | address = XEXP (address, 0); | |
1116 | } | |
1117 | ||
1118 | if (const_or_frame_p (address)) | |
1119 | { | |
1120 | group_info_t group = get_group_info (address); | |
1121 | ||
1122 | if (dump_file) | |
1123 | fprintf (dump_file, " gid=%d offset=%d \n", group->id, (int)*offset); | |
1124 | *base = NULL; | |
1125 | *group_id = group->id; | |
1126 | } | |
1127 | else | |
1128 | { | |
1129 | *base = cselib_lookup (address, Pmode, true); | |
1130 | *group_id = -1; | |
1131 | ||
1132 | if (*base == NULL) | |
1133 | { | |
1134 | if (dump_file) | |
1135 | fprintf (dump_file, " no cselib val - should be a wild read.\n"); | |
1136 | return false; | |
1137 | } | |
1138 | if (dump_file) | |
1139 | fprintf (dump_file, " varying cselib base=%d offset = %d\n", | |
1140 | (*base)->value, (int)*offset); | |
1141 | } | |
1142 | return true; | |
1143 | } | |
1144 | ||
1145 | ||
1146 | /* Clear the rhs field from the active_local_stores array. */ | |
1147 | ||
1148 | static void | |
1149 | clear_rhs_from_active_local_stores (void) | |
1150 | { | |
1151 | insn_info_t ptr = active_local_stores; | |
1152 | ||
1153 | while (ptr) | |
1154 | { | |
1155 | store_info_t store_info = ptr->store_rec; | |
1156 | /* Skip the clobbers. */ | |
1157 | while (!store_info->is_set) | |
1158 | store_info = store_info->next; | |
1159 | ||
1160 | store_info->rhs = NULL; | |
1161 | ||
1162 | ptr = ptr->next_local_store; | |
1163 | } | |
1164 | } | |
1165 | ||
1166 | ||
1167 | /* BODY is an instruction pattern that belongs to INSN. Return 1 if | |
1168 | there is a candidate store, after adding it to the appropriate | |
1169 | local store group if so. */ | |
1170 | ||
1171 | static int | |
1172 | record_store (rtx body, bb_info_t bb_info) | |
1173 | { | |
1174 | rtx mem; | |
1175 | HOST_WIDE_INT offset = 0; | |
1176 | HOST_WIDE_INT width = 0; | |
32c2fdea | 1177 | alias_set_type spill_alias_set; |
3072d30e | 1178 | insn_info_t insn_info = bb_info->last_insn; |
1179 | store_info_t store_info = NULL; | |
1180 | int group_id; | |
1181 | cselib_val *base = NULL; | |
1182 | insn_info_t ptr, last; | |
1183 | bool store_is_unused; | |
1184 | ||
1185 | if (GET_CODE (body) != SET && GET_CODE (body) != CLOBBER) | |
1186 | return 0; | |
1187 | ||
1188 | /* If this is not used, then this cannot be used to keep the insn | |
1189 | from being deleted. On the other hand, it does provide something | |
1190 | that can be used to prove that another store is dead. */ | |
1191 | store_is_unused | |
1192 | = (find_reg_note (insn_info->insn, REG_UNUSED, body) != NULL); | |
1193 | ||
1194 | /* Check whether that value is a suitable memory location. */ | |
1195 | mem = SET_DEST (body); | |
1196 | if (!MEM_P (mem)) | |
1197 | { | |
1198 | /* If the set or clobber is unused, then it does not effect our | |
1199 | ability to get rid of the entire insn. */ | |
1200 | if (!store_is_unused) | |
1201 | insn_info->cannot_delete = true; | |
1202 | return 0; | |
1203 | } | |
1204 | ||
1205 | /* At this point we know mem is a mem. */ | |
1206 | if (GET_MODE (mem) == BLKmode) | |
1207 | { | |
1208 | if (GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
1209 | { | |
1210 | if (dump_file) | |
1211 | fprintf (dump_file, " adding wild read for (clobber (mem:BLK (scratch))\n"); | |
1212 | add_wild_read (bb_info); | |
1213 | insn_info->cannot_delete = true; | |
1214 | } | |
1215 | else if (!store_is_unused) | |
1216 | { | |
1217 | /* If the set or clobber is unused, then it does not effect our | |
1218 | ability to get rid of the entire insn. */ | |
1219 | insn_info->cannot_delete = true; | |
1220 | clear_rhs_from_active_local_stores (); | |
1221 | } | |
1222 | return 0; | |
1223 | } | |
1224 | ||
1225 | /* We can still process a volatile mem, we just cannot delete it. */ | |
1226 | if (MEM_VOLATILE_P (mem)) | |
1227 | insn_info->cannot_delete = true; | |
1228 | ||
1229 | if (!canon_address (mem, &spill_alias_set, &group_id, &offset, &base)) | |
1230 | { | |
1231 | clear_rhs_from_active_local_stores (); | |
1232 | return 0; | |
1233 | } | |
1234 | ||
1235 | width = GET_MODE_SIZE (GET_MODE (mem)); | |
1236 | ||
1237 | if (spill_alias_set) | |
1238 | { | |
1239 | bitmap store1 = clear_alias_group->store1_p; | |
1240 | bitmap store2 = clear_alias_group->store2_p; | |
1241 | ||
1242 | if (bitmap_bit_p (store1, spill_alias_set)) | |
1243 | bitmap_set_bit (store2, spill_alias_set); | |
1244 | else | |
1245 | bitmap_set_bit (store1, spill_alias_set); | |
1246 | ||
1247 | if (clear_alias_group->offset_map_size_p < spill_alias_set) | |
1248 | clear_alias_group->offset_map_size_p = spill_alias_set; | |
1249 | ||
364c0c59 | 1250 | store_info = (store_info_t) pool_alloc (rtx_store_info_pool); |
3072d30e | 1251 | |
1252 | if (dump_file) | |
1253 | fprintf (dump_file, " processing spill store %d(%s)\n", | |
32c2fdea | 1254 | (int) spill_alias_set, GET_MODE_NAME (GET_MODE (mem))); |
3072d30e | 1255 | } |
1256 | else if (group_id >= 0) | |
1257 | { | |
1258 | /* In the restrictive case where the base is a constant or the | |
1259 | frame pointer we can do global analysis. */ | |
1260 | ||
1261 | group_info_t group | |
1262 | = VEC_index (group_info_t, rtx_group_vec, group_id); | |
1263 | ||
364c0c59 | 1264 | store_info = (store_info_t) pool_alloc (rtx_store_info_pool); |
3072d30e | 1265 | set_usage_bits (group, offset, width); |
1266 | ||
1267 | if (dump_file) | |
1268 | fprintf (dump_file, " processing const base store gid=%d[%d..%d)\n", | |
1269 | group_id, (int)offset, (int)(offset+width)); | |
1270 | } | |
1271 | else | |
1272 | { | |
17e1318c | 1273 | rtx base_term = find_base_term (XEXP (mem, 0)); |
1274 | if (!base_term | |
1275 | || (GET_CODE (base_term) == ADDRESS | |
1276 | && GET_MODE (base_term) == Pmode | |
1277 | && XEXP (base_term, 0) == stack_pointer_rtx)) | |
1278 | insn_info->stack_pointer_based = true; | |
3072d30e | 1279 | insn_info->contains_cselib_groups = true; |
17e1318c | 1280 | |
364c0c59 | 1281 | store_info = (store_info_t) pool_alloc (cse_store_info_pool); |
3072d30e | 1282 | group_id = -1; |
1283 | ||
1284 | if (dump_file) | |
1285 | fprintf (dump_file, " processing cselib store [%d..%d)\n", | |
1286 | (int)offset, (int)(offset+width)); | |
1287 | } | |
1288 | ||
1289 | /* Check to see if this stores causes some other stores to be | |
1290 | dead. */ | |
1291 | ptr = active_local_stores; | |
1292 | last = NULL; | |
1293 | ||
1294 | while (ptr) | |
1295 | { | |
1296 | insn_info_t next = ptr->next_local_store; | |
1297 | store_info_t s_info = ptr->store_rec; | |
9ce37fa7 | 1298 | bool del = true; |
3072d30e | 1299 | |
1300 | /* Skip the clobbers. We delete the active insn if this insn | |
6dfdc153 | 1301 | shadows the set. To have been put on the active list, it |
3072d30e | 1302 | has exactly on set. */ |
1303 | while (!s_info->is_set) | |
1304 | s_info = s_info->next; | |
1305 | ||
1306 | if (s_info->alias_set != spill_alias_set) | |
9ce37fa7 | 1307 | del = false; |
3072d30e | 1308 | else if (s_info->alias_set) |
1309 | { | |
1310 | struct clear_alias_mode_holder *entry | |
1311 | = clear_alias_set_lookup (s_info->alias_set); | |
1312 | /* Generally, spills cannot be processed if and of the | |
1313 | references to the slot have a different mode. But if | |
1314 | we are in the same block and mode is exactly the same | |
1315 | between this store and one before in the same block, | |
1316 | we can still delete it. */ | |
1317 | if ((GET_MODE (mem) == GET_MODE (s_info->mem)) | |
1318 | && (GET_MODE (mem) == entry->mode)) | |
1319 | { | |
9ce37fa7 | 1320 | del = true; |
4e43e20a | 1321 | s_info->positions_needed = (unsigned HOST_WIDE_INT) 0; |
3072d30e | 1322 | } |
1323 | if (dump_file) | |
1324 | fprintf (dump_file, " trying spill store in insn=%d alias_set=%d\n", | |
32c2fdea | 1325 | INSN_UID (ptr->insn), (int) s_info->alias_set); |
3072d30e | 1326 | } |
1327 | else if ((s_info->group_id == group_id) | |
1328 | && (s_info->cse_base == base)) | |
1329 | { | |
1330 | HOST_WIDE_INT i; | |
1331 | if (dump_file) | |
1332 | fprintf (dump_file, " trying store in insn=%d gid=%d[%d..%d)\n", | |
1333 | INSN_UID (ptr->insn), s_info->group_id, | |
1334 | (int)s_info->begin, (int)s_info->end); | |
1335 | for (i = offset; i < offset+width; i++) | |
1336 | if (i >= s_info->begin && i < s_info->end) | |
4e43e20a | 1337 | s_info->positions_needed |
1338 | &= ~(((unsigned HOST_WIDE_INT) 1) << (i - s_info->begin)); | |
3072d30e | 1339 | } |
1340 | else if (s_info->rhs) | |
1341 | /* Need to see if it is possible for this store to overwrite | |
1342 | the value of store_info. If it is, set the rhs to NULL to | |
1343 | keep it from being used to remove a load. */ | |
1344 | { | |
1345 | if (canon_true_dependence (s_info->mem, | |
1346 | GET_MODE (s_info->mem), | |
1347 | s_info->mem_addr, | |
1348 | mem, rtx_varies_p)) | |
1349 | s_info->rhs = NULL; | |
1350 | } | |
1351 | ||
1352 | /* An insn can be deleted if every position of every one of | |
1353 | its s_infos is zero. */ | |
4e43e20a | 1354 | if (s_info->positions_needed != (unsigned HOST_WIDE_INT) 0) |
9ce37fa7 | 1355 | del = false; |
3072d30e | 1356 | |
9ce37fa7 | 1357 | if (del) |
3072d30e | 1358 | { |
1359 | insn_info_t insn_to_delete = ptr; | |
1360 | ||
1361 | if (last) | |
1362 | last->next_local_store = ptr->next_local_store; | |
1363 | else | |
1364 | active_local_stores = ptr->next_local_store; | |
1365 | ||
1366 | delete_dead_store_insn (insn_to_delete); | |
1367 | } | |
1368 | else | |
1369 | last = ptr; | |
1370 | ||
1371 | ptr = next; | |
1372 | } | |
1373 | ||
07509ef3 | 1374 | gcc_assert ((unsigned) width <= HOST_BITS_PER_WIDE_INT); |
3072d30e | 1375 | |
1376 | /* Finish filling in the store_info. */ | |
1377 | store_info->next = insn_info->store_rec; | |
1378 | insn_info->store_rec = store_info; | |
1379 | store_info->mem = canon_rtx (mem); | |
1380 | store_info->alias_set = spill_alias_set; | |
1381 | store_info->mem_addr = get_addr (XEXP (mem, 0)); | |
1382 | store_info->cse_base = base; | |
4e43e20a | 1383 | store_info->positions_needed = lowpart_bitmask (width); |
3072d30e | 1384 | store_info->group_id = group_id; |
1385 | store_info->begin = offset; | |
1386 | store_info->end = offset + width; | |
1387 | store_info->is_set = GET_CODE (body) == SET; | |
1388 | ||
1389 | if (store_info->is_set | |
1390 | /* No place to keep the value after ra. */ | |
1391 | && !reload_completed | |
10d4de0e | 1392 | && (REG_P (SET_SRC (body)) |
1393 | || GET_CODE (SET_SRC (body)) == SUBREG | |
1394 | || CONSTANT_P (SET_SRC (body))) | |
3072d30e | 1395 | /* Sometimes the store and reload is used for truncation and |
1396 | rounding. */ | |
1397 | && !(FLOAT_MODE_P (GET_MODE (mem)) && (flag_float_store))) | |
1398 | store_info->rhs = SET_SRC (body); | |
1399 | else | |
1400 | store_info->rhs = NULL; | |
1401 | ||
1402 | /* If this is a clobber, we return 0. We will only be able to | |
1403 | delete this insn if there is only one store USED store, but we | |
1404 | can use the clobber to delete other stores earlier. */ | |
1405 | return store_info->is_set ? 1 : 0; | |
1406 | } | |
1407 | ||
1408 | ||
1409 | static void | |
1410 | dump_insn_info (const char * start, insn_info_t insn_info) | |
1411 | { | |
1412 | fprintf (dump_file, "%s insn=%d %s\n", start, | |
1413 | INSN_UID (insn_info->insn), | |
1414 | insn_info->store_rec ? "has store" : "naked"); | |
1415 | } | |
1416 | ||
1417 | ||
5c9051a4 | 1418 | /* If the modes are different and the value's source and target do not |
1419 | line up, we need to extract the value from lower part of the rhs of | |
1420 | the store, shift it, and then put it into a form that can be shoved | |
1421 | into the read_insn. This function generates a right SHIFT of a | |
1422 | value that is at least ACCESS_SIZE bytes wide of READ_MODE. The | |
1423 | shift sequence is returned or NULL if we failed to find a | |
1424 | shift. */ | |
1425 | ||
1426 | static rtx | |
10d4de0e | 1427 | find_shift_sequence (int access_size, |
5c9051a4 | 1428 | store_info_t store_info, |
1429 | read_info_t read_info, | |
1430 | int shift) | |
1431 | { | |
1432 | enum machine_mode store_mode = GET_MODE (store_info->mem); | |
1433 | enum machine_mode read_mode = GET_MODE (read_info->mem); | |
10d4de0e | 1434 | enum machine_mode new_mode; |
1435 | rtx read_reg = NULL; | |
5c9051a4 | 1436 | |
1437 | /* Some machines like the x86 have shift insns for each size of | |
1438 | operand. Other machines like the ppc or the ia-64 may only have | |
1439 | shift insns that shift values within 32 or 64 bit registers. | |
1440 | This loop tries to find the smallest shift insn that will right | |
1441 | justify the value we want to read but is available in one insn on | |
1442 | the machine. */ | |
1443 | ||
10d4de0e | 1444 | for (new_mode = smallest_mode_for_size (access_size * BITS_PER_UNIT, |
1445 | MODE_INT); | |
1446 | GET_MODE_BITSIZE (new_mode) <= BITS_PER_WORD; | |
1447 | new_mode = GET_MODE_WIDER_MODE (new_mode)) | |
5c9051a4 | 1448 | { |
10d4de0e | 1449 | rtx target, new_reg, shift_seq, insn, new_lhs; |
a6c18cd6 | 1450 | int cost, offset; |
af97461e | 1451 | |
10d4de0e | 1452 | /* Try a wider mode if truncating the store mode to NEW_MODE |
1453 | requires a real instruction. */ | |
1454 | if (GET_MODE_BITSIZE (new_mode) < GET_MODE_BITSIZE (store_mode) | |
1455 | && !TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (new_mode), | |
af97461e | 1456 | GET_MODE_BITSIZE (store_mode))) |
1457 | continue; | |
1458 | ||
10d4de0e | 1459 | /* Also try a wider mode if the necessary punning is either not |
1460 | desirable or not possible. */ | |
1461 | if (!CONSTANT_P (store_info->rhs) | |
1462 | && !MODES_TIEABLE_P (new_mode, store_mode)) | |
1463 | continue; | |
a6c18cd6 | 1464 | offset = subreg_lowpart_offset (new_mode, store_mode); |
10d4de0e | 1465 | new_lhs = simplify_gen_subreg (new_mode, copy_rtx (store_info->rhs), |
a6c18cd6 | 1466 | store_mode, offset); |
10d4de0e | 1467 | if (new_lhs == NULL_RTX) |
1468 | continue; | |
1469 | ||
af97461e | 1470 | new_reg = gen_reg_rtx (new_mode); |
5c9051a4 | 1471 | |
1472 | start_sequence (); | |
1473 | ||
1474 | /* In theory we could also check for an ashr. Ian Taylor knows | |
1475 | of one dsp where the cost of these two was not the same. But | |
1476 | this really is a rare case anyway. */ | |
1477 | target = expand_binop (new_mode, lshr_optab, new_reg, | |
1478 | GEN_INT (shift), new_reg, 1, OPTAB_DIRECT); | |
1479 | ||
597d5470 | 1480 | shift_seq = get_insns (); |
1481 | end_sequence (); | |
5c9051a4 | 1482 | |
597d5470 | 1483 | if (target != new_reg || shift_seq == NULL) |
1484 | continue; | |
1485 | ||
1486 | cost = 0; | |
1487 | for (insn = shift_seq; insn != NULL_RTX; insn = NEXT_INSN (insn)) | |
1488 | if (INSN_P (insn)) | |
1489 | cost += insn_rtx_cost (PATTERN (insn)); | |
1490 | ||
1491 | /* The computation up to here is essentially independent | |
1492 | of the arguments and could be precomputed. It may | |
1493 | not be worth doing so. We could precompute if | |
1494 | worthwhile or at least cache the results. The result | |
5133fd21 | 1495 | technically depends on both SHIFT and ACCESS_SIZE, |
1496 | but in practice the answer will depend only on ACCESS_SIZE. */ | |
597d5470 | 1497 | |
1498 | if (cost > COSTS_N_INSNS (1)) | |
1499 | continue; | |
1500 | ||
1501 | /* We found an acceptable shift. Generate a move to | |
1502 | take the value from the store and put it into the | |
1503 | shift pseudo, then shift it, then generate another | |
1504 | move to put in into the target of the read. */ | |
10d4de0e | 1505 | emit_move_insn (new_reg, new_lhs); |
597d5470 | 1506 | emit_insn (shift_seq); |
10d4de0e | 1507 | read_reg = extract_low_bits (read_mode, new_mode, new_reg); |
597d5470 | 1508 | break; |
5c9051a4 | 1509 | } |
1510 | ||
10d4de0e | 1511 | return read_reg; |
5c9051a4 | 1512 | } |
1513 | ||
1514 | ||
3072d30e | 1515 | /* Take a sequence of: |
1516 | A <- r1 | |
1517 | ... | |
1518 | ... <- A | |
1519 | ||
1520 | and change it into | |
1521 | r2 <- r1 | |
1522 | A <- r1 | |
1523 | ... | |
1524 | ... <- r2 | |
1525 | ||
5c9051a4 | 1526 | or |
1527 | ||
1528 | r3 <- extract (r1) | |
1529 | r3 <- r3 >> shift | |
1530 | r2 <- extract (r3) | |
1531 | ... <- r2 | |
1532 | ||
1533 | or | |
1534 | ||
1535 | r2 <- extract (r1) | |
1536 | ... <- r2 | |
1537 | ||
1538 | Depending on the alignment and the mode of the store and | |
1539 | subsequent load. | |
1540 | ||
1541 | ||
1542 | The STORE_INFO and STORE_INSN are for the store and READ_INFO | |
3072d30e | 1543 | and READ_INSN are for the read. Return true if the replacement |
1544 | went ok. */ | |
1545 | ||
1546 | static bool | |
1547 | replace_read (store_info_t store_info, insn_info_t store_insn, | |
1548 | read_info_t read_info, insn_info_t read_insn, rtx *loc) | |
1549 | { | |
5c9051a4 | 1550 | enum machine_mode store_mode = GET_MODE (store_info->mem); |
1551 | enum machine_mode read_mode = GET_MODE (read_info->mem); | |
1552 | int shift; | |
1553 | int access_size; /* In bytes. */ | |
10d4de0e | 1554 | rtx insns, read_reg; |
5c9051a4 | 1555 | |
3072d30e | 1556 | if (!dbg_cnt (dse)) |
1557 | return false; | |
1558 | ||
5c9051a4 | 1559 | /* To get here the read is within the boundaries of the write so |
1560 | shift will never be negative. Start out with the shift being in | |
1561 | bytes. */ | |
1562 | if (BYTES_BIG_ENDIAN) | |
1563 | shift = store_info->end - read_info->end; | |
1564 | else | |
1565 | shift = read_info->begin - store_info->begin; | |
1566 | ||
1567 | access_size = shift + GET_MODE_SIZE (read_mode); | |
1568 | ||
1569 | /* From now on it is bits. */ | |
1570 | shift *= BITS_PER_UNIT; | |
1571 | ||
10d4de0e | 1572 | /* Create a sequence of instructions to set up the read register. |
1573 | This sequence goes immediately before the store and its result | |
1574 | is read by the load. | |
1575 | ||
1576 | We need to keep this in perspective. We are replacing a read | |
5c9051a4 | 1577 | with a sequence of insns, but the read will almost certainly be |
1578 | in cache, so it is not going to be an expensive one. Thus, we | |
1579 | are not willing to do a multi insn shift or worse a subroutine | |
1580 | call to get rid of the read. */ | |
10d4de0e | 1581 | if (dump_file) |
1582 | fprintf (dump_file, "trying to replace %smode load in insn %d" | |
1583 | " from %smode store in insn %d\n", | |
1584 | GET_MODE_NAME (read_mode), INSN_UID (read_insn->insn), | |
1585 | GET_MODE_NAME (store_mode), INSN_UID (store_insn->insn)); | |
1586 | start_sequence (); | |
5c9051a4 | 1587 | if (shift) |
10d4de0e | 1588 | read_reg = find_shift_sequence (access_size, store_info, read_info, shift); |
1589 | else | |
1590 | read_reg = extract_low_bits (read_mode, store_mode, | |
1591 | copy_rtx (store_info->rhs)); | |
1592 | if (read_reg == NULL_RTX) | |
5c9051a4 | 1593 | { |
10d4de0e | 1594 | end_sequence (); |
1595 | if (dump_file) | |
1596 | fprintf (dump_file, " -- could not extract bits of stored value\n"); | |
1597 | return false; | |
5c9051a4 | 1598 | } |
10d4de0e | 1599 | /* Force the value into a new register so that it won't be clobbered |
1600 | between the store and the load. */ | |
1601 | read_reg = copy_to_mode_reg (read_mode, read_reg); | |
1602 | insns = get_insns (); | |
1603 | end_sequence (); | |
5c9051a4 | 1604 | |
1605 | if (validate_change (read_insn->insn, loc, read_reg, 0)) | |
3072d30e | 1606 | { |
364c0c59 | 1607 | deferred_change_t deferred_change = |
1608 | (deferred_change_t) pool_alloc (deferred_change_pool); | |
5c9051a4 | 1609 | |
5c9051a4 | 1610 | /* Insert this right before the store insn where it will be safe |
1611 | from later insns that might change it before the read. */ | |
1612 | emit_insn_before (insns, store_insn->insn); | |
1613 | ||
1614 | /* And now for the kludge part: cselib croaks if you just | |
1615 | return at this point. There are two reasons for this: | |
1616 | ||
1617 | 1) Cselib has an idea of how many pseudos there are and | |
1618 | that does not include the new ones we just added. | |
1619 | ||
1620 | 2) Cselib does not know about the move insn we added | |
1621 | above the store_info, and there is no way to tell it | |
1622 | about it, because it has "moved on". | |
1623 | ||
1624 | Problem (1) is fixable with a certain amount of engineering. | |
1625 | Problem (2) is requires starting the bb from scratch. This | |
1626 | could be expensive. | |
1627 | ||
1628 | So we are just going to have to lie. The move/extraction | |
1629 | insns are not really an issue, cselib did not see them. But | |
1630 | the use of the new pseudo read_insn is a real problem because | |
1631 | cselib has not scanned this insn. The way that we solve this | |
1632 | problem is that we are just going to put the mem back for now | |
1633 | and when we are finished with the block, we undo this. We | |
1634 | keep a table of mems to get rid of. At the end of the basic | |
1635 | block we can put them back. */ | |
1636 | ||
1637 | *loc = read_info->mem; | |
1638 | deferred_change->next = deferred_change_list; | |
1639 | deferred_change_list = deferred_change; | |
1640 | deferred_change->loc = loc; | |
1641 | deferred_change->reg = read_reg; | |
1642 | ||
1643 | /* Get rid of the read_info, from the point of view of the | |
1644 | rest of dse, play like this read never happened. */ | |
1645 | read_insn->read_rec = read_info->next; | |
1646 | pool_free (read_info_pool, read_info); | |
10d4de0e | 1647 | if (dump_file) |
1648 | { | |
1649 | fprintf (dump_file, " -- replaced the loaded MEM with "); | |
1650 | print_simple_rtl (dump_file, read_reg); | |
1651 | fprintf (dump_file, "\n"); | |
1652 | } | |
5c9051a4 | 1653 | return true; |
3072d30e | 1654 | } |
5c9051a4 | 1655 | else |
3072d30e | 1656 | { |
3072d30e | 1657 | if (dump_file) |
10d4de0e | 1658 | { |
1659 | fprintf (dump_file, " -- replacing the loaded MEM with "); | |
1660 | print_simple_rtl (dump_file, read_reg); | |
1661 | fprintf (dump_file, " led to an invalid instruction\n"); | |
1662 | } | |
3072d30e | 1663 | return false; |
1664 | } | |
1665 | } | |
1666 | ||
3072d30e | 1667 | /* A for_each_rtx callback in which DATA is the bb_info. Check to see |
1668 | if LOC is a mem and if it is look at the address and kill any | |
1669 | appropriate stores that may be active. */ | |
1670 | ||
1671 | static int | |
1672 | check_mem_read_rtx (rtx *loc, void *data) | |
1673 | { | |
1674 | rtx mem = *loc; | |
1675 | bb_info_t bb_info; | |
1676 | insn_info_t insn_info; | |
1677 | HOST_WIDE_INT offset = 0; | |
1678 | HOST_WIDE_INT width = 0; | |
32c2fdea | 1679 | alias_set_type spill_alias_set = 0; |
3072d30e | 1680 | cselib_val *base = NULL; |
1681 | int group_id; | |
1682 | read_info_t read_info; | |
1683 | ||
1684 | if (!mem || !MEM_P (mem)) | |
1685 | return 0; | |
1686 | ||
1687 | bb_info = (bb_info_t) data; | |
1688 | insn_info = bb_info->last_insn; | |
1689 | ||
1690 | if ((MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
1691 | || (MEM_VOLATILE_P (mem))) | |
1692 | { | |
1693 | if (dump_file) | |
1694 | fprintf (dump_file, " adding wild read, volatile or barrier.\n"); | |
1695 | add_wild_read (bb_info); | |
1696 | insn_info->cannot_delete = true; | |
1697 | return 0; | |
1698 | } | |
1699 | ||
1700 | /* If it is reading readonly mem, then there can be no conflict with | |
1701 | another write. */ | |
1702 | if (MEM_READONLY_P (mem)) | |
1703 | return 0; | |
1704 | ||
1705 | if (!canon_address (mem, &spill_alias_set, &group_id, &offset, &base)) | |
1706 | { | |
1707 | if (dump_file) | |
1708 | fprintf (dump_file, " adding wild read, canon_address failure.\n"); | |
1709 | add_wild_read (bb_info); | |
1710 | return 0; | |
1711 | } | |
1712 | ||
1713 | if (GET_MODE (mem) == BLKmode) | |
1714 | width = -1; | |
1715 | else | |
1716 | width = GET_MODE_SIZE (GET_MODE (mem)); | |
1717 | ||
364c0c59 | 1718 | read_info = (read_info_t) pool_alloc (read_info_pool); |
3072d30e | 1719 | read_info->group_id = group_id; |
1720 | read_info->mem = mem; | |
1721 | read_info->alias_set = spill_alias_set; | |
1722 | read_info->begin = offset; | |
1723 | read_info->end = offset + width; | |
1724 | read_info->next = insn_info->read_rec; | |
1725 | insn_info->read_rec = read_info; | |
1726 | ||
bef304b8 | 1727 | /* We ignore the clobbers in store_info. The is mildly aggressive, |
3072d30e | 1728 | but there really should not be a clobber followed by a read. */ |
1729 | ||
1730 | if (spill_alias_set) | |
1731 | { | |
1732 | insn_info_t i_ptr = active_local_stores; | |
1733 | insn_info_t last = NULL; | |
1734 | ||
1735 | if (dump_file) | |
1736 | fprintf (dump_file, " processing spill load %d\n", | |
32c2fdea | 1737 | (int) spill_alias_set); |
3072d30e | 1738 | |
1739 | while (i_ptr) | |
1740 | { | |
1741 | store_info_t store_info = i_ptr->store_rec; | |
1742 | ||
1743 | /* Skip the clobbers. */ | |
1744 | while (!store_info->is_set) | |
1745 | store_info = store_info->next; | |
1746 | ||
1747 | if (store_info->alias_set == spill_alias_set) | |
1748 | { | |
1749 | if (dump_file) | |
1750 | dump_insn_info ("removing from active", i_ptr); | |
1751 | ||
1752 | if (last) | |
1753 | last->next_local_store = i_ptr->next_local_store; | |
1754 | else | |
1755 | active_local_stores = i_ptr->next_local_store; | |
1756 | } | |
1757 | else | |
1758 | last = i_ptr; | |
1759 | i_ptr = i_ptr->next_local_store; | |
1760 | } | |
1761 | } | |
1762 | else if (group_id >= 0) | |
1763 | { | |
1764 | /* This is the restricted case where the base is a constant or | |
1765 | the frame pointer and offset is a constant. */ | |
1766 | insn_info_t i_ptr = active_local_stores; | |
1767 | insn_info_t last = NULL; | |
1768 | ||
1769 | if (dump_file) | |
1770 | { | |
1771 | if (width == -1) | |
1772 | fprintf (dump_file, " processing const load gid=%d[BLK]\n", | |
1773 | group_id); | |
1774 | else | |
1775 | fprintf (dump_file, " processing const load gid=%d[%d..%d)\n", | |
1776 | group_id, (int)offset, (int)(offset+width)); | |
1777 | } | |
1778 | ||
1779 | while (i_ptr) | |
1780 | { | |
1781 | bool remove = false; | |
1782 | store_info_t store_info = i_ptr->store_rec; | |
1783 | ||
1784 | /* Skip the clobbers. */ | |
1785 | while (!store_info->is_set) | |
1786 | store_info = store_info->next; | |
1787 | ||
1788 | /* There are three cases here. */ | |
1789 | if (store_info->group_id < 0) | |
1790 | /* We have a cselib store followed by a read from a | |
1791 | const base. */ | |
1792 | remove | |
1793 | = canon_true_dependence (store_info->mem, | |
1794 | GET_MODE (store_info->mem), | |
1795 | store_info->mem_addr, | |
1796 | mem, rtx_varies_p); | |
1797 | ||
1798 | else if (group_id == store_info->group_id) | |
1799 | { | |
1800 | /* This is a block mode load. We may get lucky and | |
1801 | canon_true_dependence may save the day. */ | |
1802 | if (width == -1) | |
1803 | remove | |
1804 | = canon_true_dependence (store_info->mem, | |
1805 | GET_MODE (store_info->mem), | |
1806 | store_info->mem_addr, | |
1807 | mem, rtx_varies_p); | |
1808 | ||
1809 | /* If this read is just reading back something that we just | |
1810 | stored, rewrite the read. */ | |
1811 | else | |
1812 | { | |
1813 | if (store_info->rhs | |
1814 | && (offset >= store_info->begin) | |
1815 | && (offset + width <= store_info->end)) | |
1816 | { | |
4e43e20a | 1817 | unsigned HOST_WIDE_INT mask |
1818 | = (lowpart_bitmask (width) | |
1819 | << (offset - store_info->begin)); | |
1820 | ||
3072d30e | 1821 | if ((store_info->positions_needed & mask) == mask |
1822 | && replace_read (store_info, i_ptr, | |
1823 | read_info, insn_info, loc)) | |
1824 | return 0; | |
1825 | } | |
1826 | /* The bases are the same, just see if the offsets | |
1827 | overlap. */ | |
1828 | if ((offset < store_info->end) | |
1829 | && (offset + width > store_info->begin)) | |
1830 | remove = true; | |
1831 | } | |
1832 | } | |
1833 | ||
1834 | /* else | |
1835 | The else case that is missing here is that the | |
1836 | bases are constant but different. There is nothing | |
1837 | to do here because there is no overlap. */ | |
1838 | ||
1839 | if (remove) | |
1840 | { | |
1841 | if (dump_file) | |
1842 | dump_insn_info ("removing from active", i_ptr); | |
1843 | ||
1844 | if (last) | |
1845 | last->next_local_store = i_ptr->next_local_store; | |
1846 | else | |
1847 | active_local_stores = i_ptr->next_local_store; | |
1848 | } | |
1849 | else | |
1850 | last = i_ptr; | |
1851 | i_ptr = i_ptr->next_local_store; | |
1852 | } | |
1853 | } | |
1854 | else | |
1855 | { | |
1856 | insn_info_t i_ptr = active_local_stores; | |
1857 | insn_info_t last = NULL; | |
1858 | if (dump_file) | |
1859 | { | |
1860 | fprintf (dump_file, " processing cselib load mem:"); | |
1861 | print_inline_rtx (dump_file, mem, 0); | |
1862 | fprintf (dump_file, "\n"); | |
1863 | } | |
1864 | ||
1865 | while (i_ptr) | |
1866 | { | |
1867 | bool remove = false; | |
1868 | store_info_t store_info = i_ptr->store_rec; | |
1869 | ||
1870 | if (dump_file) | |
1871 | fprintf (dump_file, " processing cselib load against insn %d\n", | |
1872 | INSN_UID (i_ptr->insn)); | |
1873 | ||
1874 | /* Skip the clobbers. */ | |
1875 | while (!store_info->is_set) | |
1876 | store_info = store_info->next; | |
1877 | ||
1878 | /* If this read is just reading back something that we just | |
1879 | stored, rewrite the read. */ | |
1880 | if (store_info->rhs | |
1881 | && store_info->group_id == -1 | |
1882 | && store_info->cse_base == base | |
1883 | && (offset >= store_info->begin) | |
1884 | && (offset + width <= store_info->end)) | |
1885 | { | |
4e43e20a | 1886 | unsigned HOST_WIDE_INT mask |
1887 | = (lowpart_bitmask (width) | |
1888 | << (offset - store_info->begin)); | |
1889 | ||
3072d30e | 1890 | if ((store_info->positions_needed & mask) == mask |
1891 | && replace_read (store_info, i_ptr, | |
1892 | read_info, insn_info, loc)) | |
1893 | return 0; | |
1894 | } | |
1895 | ||
1896 | if (!store_info->alias_set) | |
1897 | remove = canon_true_dependence (store_info->mem, | |
1898 | GET_MODE (store_info->mem), | |
1899 | store_info->mem_addr, | |
1900 | mem, rtx_varies_p); | |
1901 | ||
1902 | if (remove) | |
1903 | { | |
1904 | if (dump_file) | |
1905 | dump_insn_info ("removing from active", i_ptr); | |
1906 | ||
1907 | if (last) | |
1908 | last->next_local_store = i_ptr->next_local_store; | |
1909 | else | |
1910 | active_local_stores = i_ptr->next_local_store; | |
1911 | } | |
1912 | else | |
1913 | last = i_ptr; | |
1914 | i_ptr = i_ptr->next_local_store; | |
1915 | } | |
1916 | } | |
1917 | return 0; | |
1918 | } | |
1919 | ||
1920 | /* A for_each_rtx callback in which DATA points the INSN_INFO for | |
1921 | as check_mem_read_rtx. Nullify the pointer if i_m_r_m_r returns | |
1922 | true for any part of *LOC. */ | |
1923 | ||
1924 | static void | |
1925 | check_mem_read_use (rtx *loc, void *data) | |
1926 | { | |
1927 | for_each_rtx (loc, check_mem_read_rtx, data); | |
1928 | } | |
1929 | ||
1930 | /* Apply record_store to all candidate stores in INSN. Mark INSN | |
1931 | if some part of it is not a candidate store and assigns to a | |
1932 | non-register target. */ | |
1933 | ||
1934 | static void | |
1935 | scan_insn (bb_info_t bb_info, rtx insn) | |
1936 | { | |
1937 | rtx body; | |
364c0c59 | 1938 | insn_info_t insn_info = (insn_info_t) pool_alloc (insn_info_pool); |
3072d30e | 1939 | int mems_found = 0; |
1940 | memset (insn_info, 0, sizeof (struct insn_info)); | |
1941 | ||
1942 | if (dump_file) | |
1943 | fprintf (dump_file, "\n**scanning insn=%d\n", | |
1944 | INSN_UID (insn)); | |
1945 | ||
1946 | insn_info->prev_insn = bb_info->last_insn; | |
1947 | insn_info->insn = insn; | |
1948 | bb_info->last_insn = insn_info; | |
1949 | ||
1950 | ||
bef304b8 | 1951 | /* Cselib clears the table for this case, so we have to essentially |
3072d30e | 1952 | do the same. */ |
1953 | if (NONJUMP_INSN_P (insn) | |
1954 | && GET_CODE (PATTERN (insn)) == ASM_OPERANDS | |
1955 | && MEM_VOLATILE_P (PATTERN (insn))) | |
1956 | { | |
1957 | add_wild_read (bb_info); | |
1958 | insn_info->cannot_delete = true; | |
1959 | return; | |
1960 | } | |
1961 | ||
1962 | /* Look at all of the uses in the insn. */ | |
1963 | note_uses (&PATTERN (insn), check_mem_read_use, bb_info); | |
1964 | ||
1965 | if (CALL_P (insn)) | |
1966 | { | |
1967 | insn_info->cannot_delete = true; | |
17e1318c | 1968 | |
3072d30e | 1969 | /* Const functions cannot do anything bad i.e. read memory, |
17e1318c | 1970 | however, they can read their parameters which may have |
1971 | been pushed onto the stack. */ | |
9c2a0c05 | 1972 | if (RTL_CONST_CALL_P (insn)) |
3072d30e | 1973 | { |
1974 | insn_info_t i_ptr = active_local_stores; | |
1975 | insn_info_t last = NULL; | |
1976 | ||
1977 | if (dump_file) | |
1978 | fprintf (dump_file, "const call %d\n", INSN_UID (insn)); | |
1979 | ||
16bf64db | 1980 | /* See the head comment of the frame_read field. */ |
1981 | if (reload_completed) | |
1982 | insn_info->frame_read = true; | |
1983 | ||
1984 | /* Loop over the active stores and remove those which are | |
1985 | killed by the const function call. */ | |
3072d30e | 1986 | while (i_ptr) |
1987 | { | |
16bf64db | 1988 | bool remove_store = false; |
1989 | ||
1990 | /* The stack pointer based stores are always killed. */ | |
17e1318c | 1991 | if (i_ptr->stack_pointer_based) |
16bf64db | 1992 | remove_store = true; |
1993 | ||
1994 | /* If the frame is read, the frame related stores are killed. */ | |
1995 | else if (insn_info->frame_read) | |
1996 | { | |
1997 | store_info_t store_info = i_ptr->store_rec; | |
1998 | ||
1999 | /* Skip the clobbers. */ | |
2000 | while (!store_info->is_set) | |
2001 | store_info = store_info->next; | |
2002 | ||
2003 | if (store_info->group_id >= 0 | |
2004 | && VEC_index (group_info_t, rtx_group_vec, | |
2005 | store_info->group_id)->frame_related) | |
2006 | remove_store = true; | |
2007 | } | |
2008 | ||
2009 | if (remove_store) | |
3072d30e | 2010 | { |
2011 | if (dump_file) | |
2012 | dump_insn_info ("removing from active", i_ptr); | |
2013 | ||
2014 | if (last) | |
2015 | last->next_local_store = i_ptr->next_local_store; | |
2016 | else | |
2017 | active_local_stores = i_ptr->next_local_store; | |
2018 | } | |
2019 | else | |
2020 | last = i_ptr; | |
16bf64db | 2021 | |
3072d30e | 2022 | i_ptr = i_ptr->next_local_store; |
2023 | } | |
3072d30e | 2024 | } |
2025 | ||
17e1318c | 2026 | else |
2027 | /* Every other call, including pure functions, may read memory. */ | |
2028 | add_wild_read (bb_info); | |
2029 | ||
3072d30e | 2030 | return; |
2031 | } | |
2032 | ||
2033 | /* Assuming that there are sets in these insns, we cannot delete | |
2034 | them. */ | |
2035 | if ((GET_CODE (PATTERN (insn)) == CLOBBER) | |
4aafe72f | 2036 | || volatile_refs_p (PATTERN (insn)) |
3072d30e | 2037 | || (flag_non_call_exceptions && may_trap_p (PATTERN (insn))) |
2038 | || (RTX_FRAME_RELATED_P (insn)) | |
2039 | || find_reg_note (insn, REG_FRAME_RELATED_EXPR, NULL_RTX)) | |
2040 | insn_info->cannot_delete = true; | |
2041 | ||
2042 | body = PATTERN (insn); | |
2043 | if (GET_CODE (body) == PARALLEL) | |
2044 | { | |
2045 | int i; | |
2046 | for (i = 0; i < XVECLEN (body, 0); i++) | |
2047 | mems_found += record_store (XVECEXP (body, 0, i), bb_info); | |
2048 | } | |
2049 | else | |
2050 | mems_found += record_store (body, bb_info); | |
2051 | ||
2052 | if (dump_file) | |
2053 | fprintf (dump_file, "mems_found = %d, cannot_delete = %s\n", | |
2054 | mems_found, insn_info->cannot_delete ? "true" : "false"); | |
2055 | ||
2056 | /* If we found some sets of mems, and the insn has not been marked | |
2057 | cannot delete, add it into the active_local_stores so that it can | |
2058 | be locally deleted if found dead. Otherwise mark it as cannot | |
2059 | delete. This simplifies the processing later. */ | |
2060 | if (mems_found == 1 && !insn_info->cannot_delete) | |
2061 | { | |
2062 | insn_info->next_local_store = active_local_stores; | |
2063 | active_local_stores = insn_info; | |
2064 | } | |
2065 | else | |
2066 | insn_info->cannot_delete = true; | |
2067 | } | |
2068 | ||
2069 | ||
2070 | /* Remove BASE from the set of active_local_stores. This is a | |
2071 | callback from cselib that is used to get rid of the stores in | |
2072 | active_local_stores. */ | |
2073 | ||
2074 | static void | |
2075 | remove_useless_values (cselib_val *base) | |
2076 | { | |
2077 | insn_info_t insn_info = active_local_stores; | |
2078 | insn_info_t last = NULL; | |
2079 | ||
2080 | while (insn_info) | |
2081 | { | |
2082 | store_info_t store_info = insn_info->store_rec; | |
9ce37fa7 | 2083 | bool del = false; |
3072d30e | 2084 | |
2085 | /* If ANY of the store_infos match the cselib group that is | |
2086 | being deleted, then the insn can not be deleted. */ | |
2087 | while (store_info) | |
2088 | { | |
2089 | if ((store_info->group_id == -1) | |
2090 | && (store_info->cse_base == base)) | |
2091 | { | |
9ce37fa7 | 2092 | del = true; |
3072d30e | 2093 | break; |
2094 | } | |
2095 | store_info = store_info->next; | |
2096 | } | |
2097 | ||
9ce37fa7 | 2098 | if (del) |
3072d30e | 2099 | { |
2100 | if (last) | |
2101 | last->next_local_store = insn_info->next_local_store; | |
2102 | else | |
2103 | active_local_stores = insn_info->next_local_store; | |
2104 | free_store_info (insn_info); | |
2105 | } | |
2106 | else | |
2107 | last = insn_info; | |
2108 | ||
2109 | insn_info = insn_info->next_local_store; | |
2110 | } | |
2111 | } | |
2112 | ||
2113 | ||
2114 | /* Do all of step 1. */ | |
2115 | ||
2116 | static void | |
2117 | dse_step1 (void) | |
2118 | { | |
2119 | basic_block bb; | |
2120 | ||
2121 | cselib_init (false); | |
2122 | all_blocks = BITMAP_ALLOC (NULL); | |
2123 | bitmap_set_bit (all_blocks, ENTRY_BLOCK); | |
2124 | bitmap_set_bit (all_blocks, EXIT_BLOCK); | |
2125 | ||
2126 | FOR_ALL_BB (bb) | |
2127 | { | |
2128 | insn_info_t ptr; | |
364c0c59 | 2129 | bb_info_t bb_info = (bb_info_t) pool_alloc (bb_info_pool); |
3072d30e | 2130 | |
2131 | memset (bb_info, 0, sizeof (struct bb_info)); | |
2132 | bitmap_set_bit (all_blocks, bb->index); | |
2133 | ||
2134 | bb_table[bb->index] = bb_info; | |
2135 | cselib_discard_hook = remove_useless_values; | |
2136 | ||
2137 | if (bb->index >= NUM_FIXED_BLOCKS) | |
2138 | { | |
2139 | rtx insn; | |
2140 | ||
2141 | cse_store_info_pool | |
2142 | = create_alloc_pool ("cse_store_info_pool", | |
2143 | sizeof (struct store_info), 100); | |
2144 | active_local_stores = NULL; | |
2145 | cselib_clear_table (); | |
2146 | ||
2147 | /* Scan the insns. */ | |
2148 | FOR_BB_INSNS (bb, insn) | |
2149 | { | |
2150 | if (INSN_P (insn)) | |
2151 | scan_insn (bb_info, insn); | |
2152 | cselib_process_insn (insn); | |
2153 | } | |
2154 | ||
2155 | /* This is something of a hack, because the global algorithm | |
2156 | is supposed to take care of the case where stores go dead | |
2157 | at the end of the function. However, the global | |
2158 | algorithm must take a more conservative view of block | |
2159 | mode reads than the local alg does. So to get the case | |
2160 | where you have a store to the frame followed by a non | |
bef304b8 | 2161 | overlapping block more read, we look at the active local |
3072d30e | 2162 | stores at the end of the function and delete all of the |
2163 | frame and spill based ones. */ | |
2164 | if (stores_off_frame_dead_at_return | |
2165 | && (EDGE_COUNT (bb->succs) == 0 | |
2166 | || (single_succ_p (bb) | |
2167 | && single_succ (bb) == EXIT_BLOCK_PTR | |
18d50ae6 | 2168 | && ! crtl->calls_eh_return))) |
3072d30e | 2169 | { |
2170 | insn_info_t i_ptr = active_local_stores; | |
2171 | while (i_ptr) | |
2172 | { | |
2173 | store_info_t store_info = i_ptr->store_rec; | |
2174 | ||
2175 | /* Skip the clobbers. */ | |
2176 | while (!store_info->is_set) | |
2177 | store_info = store_info->next; | |
2178 | if (store_info->alias_set) | |
2179 | delete_dead_store_insn (i_ptr); | |
2180 | else | |
2181 | if (store_info->group_id >= 0) | |
2182 | { | |
2183 | group_info_t group | |
2184 | = VEC_index (group_info_t, rtx_group_vec, store_info->group_id); | |
2185 | if (group->frame_related) | |
2186 | delete_dead_store_insn (i_ptr); | |
2187 | } | |
2188 | ||
2189 | i_ptr = i_ptr->next_local_store; | |
2190 | } | |
2191 | } | |
2192 | ||
2193 | /* Get rid of the loads that were discovered in | |
2194 | replace_read. Cselib is finished with this block. */ | |
2195 | while (deferred_change_list) | |
2196 | { | |
2197 | deferred_change_t next = deferred_change_list->next; | |
2198 | ||
2199 | /* There is no reason to validate this change. That was | |
2200 | done earlier. */ | |
2201 | *deferred_change_list->loc = deferred_change_list->reg; | |
2202 | pool_free (deferred_change_pool, deferred_change_list); | |
2203 | deferred_change_list = next; | |
2204 | } | |
2205 | ||
2206 | /* Get rid of all of the cselib based store_infos in this | |
2207 | block and mark the containing insns as not being | |
2208 | deletable. */ | |
2209 | ptr = bb_info->last_insn; | |
2210 | while (ptr) | |
2211 | { | |
2212 | if (ptr->contains_cselib_groups) | |
2213 | free_store_info (ptr); | |
2214 | ptr = ptr->prev_insn; | |
2215 | } | |
2216 | ||
2217 | free_alloc_pool (cse_store_info_pool); | |
2218 | } | |
2219 | } | |
2220 | ||
2221 | cselib_finish (); | |
2222 | htab_empty (rtx_group_table); | |
2223 | } | |
2224 | ||
2225 | \f | |
2226 | /*---------------------------------------------------------------------------- | |
2227 | Second step. | |
2228 | ||
2229 | Assign each byte position in the stores that we are going to | |
2230 | analyze globally to a position in the bitmaps. Returns true if | |
6dfdc153 | 2231 | there are any bit positions assigned. |
3072d30e | 2232 | ----------------------------------------------------------------------------*/ |
2233 | ||
2234 | static void | |
2235 | dse_step2_init (void) | |
2236 | { | |
2237 | unsigned int i; | |
2238 | group_info_t group; | |
2239 | ||
2240 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) | |
2241 | { | |
2242 | /* For all non stack related bases, we only consider a store to | |
2243 | be deletable if there are two or more stores for that | |
2244 | position. This is because it takes one store to make the | |
2245 | other store redundant. However, for the stores that are | |
2246 | stack related, we consider them if there is only one store | |
2247 | for the position. We do this because the stack related | |
2248 | stores can be deleted if their is no read between them and | |
2249 | the end of the function. | |
2250 | ||
2251 | To make this work in the current framework, we take the stack | |
2252 | related bases add all of the bits from store1 into store2. | |
2253 | This has the effect of making the eligible even if there is | |
2254 | only one store. */ | |
2255 | ||
2256 | if (stores_off_frame_dead_at_return && group->frame_related) | |
2257 | { | |
2258 | bitmap_ior_into (group->store2_n, group->store1_n); | |
2259 | bitmap_ior_into (group->store2_p, group->store1_p); | |
2260 | if (dump_file) | |
2261 | fprintf (dump_file, "group %d is frame related ", i); | |
2262 | } | |
2263 | ||
2264 | group->offset_map_size_n++; | |
2265 | group->offset_map_n = XNEWVEC (int, group->offset_map_size_n); | |
2266 | group->offset_map_size_p++; | |
2267 | group->offset_map_p = XNEWVEC (int, group->offset_map_size_p); | |
2268 | group->process_globally = false; | |
2269 | if (dump_file) | |
2270 | { | |
2271 | fprintf (dump_file, "group %d(%d+%d): ", i, | |
2272 | (int)bitmap_count_bits (group->store2_n), | |
2273 | (int)bitmap_count_bits (group->store2_p)); | |
2274 | bitmap_print (dump_file, group->store2_n, "n ", " "); | |
2275 | bitmap_print (dump_file, group->store2_p, "p ", "\n"); | |
2276 | } | |
2277 | } | |
2278 | } | |
2279 | ||
2280 | ||
2281 | /* Init the offset tables for the normal case. */ | |
2282 | ||
2283 | static bool | |
2284 | dse_step2_nospill (void) | |
2285 | { | |
2286 | unsigned int i; | |
2287 | group_info_t group; | |
2288 | /* Position 0 is unused because 0 is used in the maps to mean | |
2289 | unused. */ | |
2290 | current_position = 1; | |
2291 | ||
2292 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) | |
2293 | { | |
2294 | bitmap_iterator bi; | |
2295 | unsigned int j; | |
2296 | ||
2297 | if (group == clear_alias_group) | |
2298 | continue; | |
2299 | ||
2300 | memset (group->offset_map_n, 0, sizeof(int) * group->offset_map_size_n); | |
2301 | memset (group->offset_map_p, 0, sizeof(int) * group->offset_map_size_p); | |
2302 | bitmap_clear (group->group_kill); | |
2303 | ||
2304 | EXECUTE_IF_SET_IN_BITMAP (group->store2_n, 0, j, bi) | |
2305 | { | |
2306 | bitmap_set_bit (group->group_kill, current_position); | |
2307 | group->offset_map_n[j] = current_position++; | |
2308 | group->process_globally = true; | |
2309 | } | |
2310 | EXECUTE_IF_SET_IN_BITMAP (group->store2_p, 0, j, bi) | |
2311 | { | |
2312 | bitmap_set_bit (group->group_kill, current_position); | |
2313 | group->offset_map_p[j] = current_position++; | |
2314 | group->process_globally = true; | |
2315 | } | |
2316 | } | |
2317 | return current_position != 1; | |
2318 | } | |
2319 | ||
2320 | ||
2321 | /* Init the offset tables for the spill case. */ | |
2322 | ||
2323 | static bool | |
2324 | dse_step2_spill (void) | |
2325 | { | |
2326 | unsigned int j; | |
2327 | group_info_t group = clear_alias_group; | |
2328 | bitmap_iterator bi; | |
2329 | ||
2330 | /* Position 0 is unused because 0 is used in the maps to mean | |
2331 | unused. */ | |
2332 | current_position = 1; | |
2333 | ||
2334 | if (dump_file) | |
2335 | { | |
2336 | bitmap_print (dump_file, clear_alias_sets, | |
2337 | "clear alias sets ", "\n"); | |
2338 | bitmap_print (dump_file, disqualified_clear_alias_sets, | |
2339 | "disqualified clear alias sets ", "\n"); | |
2340 | } | |
2341 | ||
2342 | memset (group->offset_map_n, 0, sizeof(int) * group->offset_map_size_n); | |
2343 | memset (group->offset_map_p, 0, sizeof(int) * group->offset_map_size_p); | |
2344 | bitmap_clear (group->group_kill); | |
2345 | ||
2346 | /* Remove the disqualified positions from the store2_p set. */ | |
2347 | bitmap_and_compl_into (group->store2_p, disqualified_clear_alias_sets); | |
2348 | ||
2349 | /* We do not need to process the store2_n set because | |
2350 | alias_sets are always positive. */ | |
2351 | EXECUTE_IF_SET_IN_BITMAP (group->store2_p, 0, j, bi) | |
2352 | { | |
2353 | bitmap_set_bit (group->group_kill, current_position); | |
2354 | group->offset_map_p[j] = current_position++; | |
2355 | group->process_globally = true; | |
2356 | } | |
2357 | ||
2358 | return current_position != 1; | |
2359 | } | |
2360 | ||
2361 | ||
2362 | \f | |
2363 | /*---------------------------------------------------------------------------- | |
2364 | Third step. | |
2365 | ||
2366 | Build the bit vectors for the transfer functions. | |
2367 | ----------------------------------------------------------------------------*/ | |
2368 | ||
2369 | ||
2370 | /* Note that this is NOT a general purpose function. Any mem that has | |
2371 | an alias set registered here expected to be COMPLETELY unaliased: | |
2372 | i.e it's addresses are not and need not be examined. | |
2373 | ||
2374 | It is known that all references to this address will have this | |
2375 | alias set and there are NO other references to this address in the | |
2376 | function. | |
2377 | ||
2378 | Currently the only place that is known to be clean enough to use | |
2379 | this interface is the code that assigns the spill locations. | |
2380 | ||
2381 | All of the mems that have alias_sets registered are subjected to a | |
2382 | very powerful form of dse where function calls, volatile reads and | |
2383 | writes, and reads from random location are not taken into account. | |
2384 | ||
2385 | It is also assumed that these locations go dead when the function | |
2386 | returns. This assumption could be relaxed if there were found to | |
2387 | be places that this assumption was not correct. | |
2388 | ||
2389 | The MODE is passed in and saved. The mode of each load or store to | |
2390 | a mem with ALIAS_SET is checked against MEM. If the size of that | |
2391 | load or store is different from MODE, processing is halted on this | |
2392 | alias set. For the vast majority of aliases sets, all of the loads | |
2393 | and stores will use the same mode. But vectors are treated | |
2394 | differently: the alias set is established for the entire vector, | |
2395 | but reload will insert loads and stores for individual elements and | |
2396 | we do not necessarily have the information to track those separate | |
2397 | elements. So when we see a mode mismatch, we just bail. */ | |
2398 | ||
2399 | ||
2400 | void | |
32c2fdea | 2401 | dse_record_singleton_alias_set (alias_set_type alias_set, |
3072d30e | 2402 | enum machine_mode mode) |
2403 | { | |
2404 | struct clear_alias_mode_holder tmp_holder; | |
2405 | struct clear_alias_mode_holder *entry; | |
2406 | void **slot; | |
2407 | ||
2408 | /* If we are not going to run dse, we need to return now or there | |
2409 | will be problems with allocating the bitmaps. */ | |
2410 | if ((!gate_dse()) || !alias_set) | |
2411 | return; | |
2412 | ||
2413 | if (!clear_alias_sets) | |
2414 | { | |
2415 | clear_alias_sets = BITMAP_ALLOC (NULL); | |
2416 | disqualified_clear_alias_sets = BITMAP_ALLOC (NULL); | |
2417 | clear_alias_mode_table = htab_create (11, clear_alias_mode_hash, | |
2418 | clear_alias_mode_eq, NULL); | |
2419 | clear_alias_mode_pool = create_alloc_pool ("clear_alias_mode_pool", | |
2420 | sizeof (struct clear_alias_mode_holder), 100); | |
2421 | } | |
2422 | ||
2423 | bitmap_set_bit (clear_alias_sets, alias_set); | |
2424 | ||
2425 | tmp_holder.alias_set = alias_set; | |
2426 | ||
2427 | slot = htab_find_slot (clear_alias_mode_table, &tmp_holder, INSERT); | |
2428 | gcc_assert (*slot == NULL); | |
2429 | ||
364c0c59 | 2430 | *slot = entry = |
2431 | (struct clear_alias_mode_holder *) pool_alloc (clear_alias_mode_pool); | |
3072d30e | 2432 | entry->alias_set = alias_set; |
2433 | entry->mode = mode; | |
2434 | } | |
2435 | ||
2436 | ||
2437 | /* Remove ALIAS_SET from the sets of stack slots being considered. */ | |
2438 | ||
2439 | void | |
32c2fdea | 2440 | dse_invalidate_singleton_alias_set (alias_set_type alias_set) |
3072d30e | 2441 | { |
2442 | if ((!gate_dse()) || !alias_set) | |
2443 | return; | |
2444 | ||
2445 | bitmap_clear_bit (clear_alias_sets, alias_set); | |
2446 | } | |
2447 | ||
2448 | ||
2449 | /* Look up the bitmap index for OFFSET in GROUP_INFO. If it is not | |
2450 | there, return 0. */ | |
2451 | ||
2452 | static int | |
2453 | get_bitmap_index (group_info_t group_info, HOST_WIDE_INT offset) | |
2454 | { | |
2455 | if (offset < 0) | |
2456 | { | |
2457 | HOST_WIDE_INT offset_p = -offset; | |
2458 | if (offset_p >= group_info->offset_map_size_n) | |
2459 | return 0; | |
2460 | return group_info->offset_map_n[offset_p]; | |
2461 | } | |
2462 | else | |
2463 | { | |
2464 | if (offset >= group_info->offset_map_size_p) | |
2465 | return 0; | |
2466 | return group_info->offset_map_p[offset]; | |
2467 | } | |
2468 | } | |
2469 | ||
2470 | ||
2471 | /* Process the STORE_INFOs into the bitmaps into GEN and KILL. KILL | |
2472 | may be NULL. */ | |
2473 | ||
2474 | static void | |
2475 | scan_stores_nospill (store_info_t store_info, bitmap gen, bitmap kill) | |
2476 | { | |
2477 | while (store_info) | |
2478 | { | |
2479 | HOST_WIDE_INT i; | |
2480 | group_info_t group_info | |
2481 | = VEC_index (group_info_t, rtx_group_vec, store_info->group_id); | |
2482 | if (group_info->process_globally) | |
2483 | for (i = store_info->begin; i < store_info->end; i++) | |
2484 | { | |
2485 | int index = get_bitmap_index (group_info, i); | |
2486 | if (index != 0) | |
2487 | { | |
2488 | bitmap_set_bit (gen, index); | |
2489 | if (kill) | |
2490 | bitmap_clear_bit (kill, index); | |
2491 | } | |
2492 | } | |
2493 | store_info = store_info->next; | |
2494 | } | |
2495 | } | |
2496 | ||
2497 | ||
2498 | /* Process the STORE_INFOs into the bitmaps into GEN and KILL. KILL | |
2499 | may be NULL. */ | |
2500 | ||
2501 | static void | |
2502 | scan_stores_spill (store_info_t store_info, bitmap gen, bitmap kill) | |
2503 | { | |
2504 | while (store_info) | |
2505 | { | |
2506 | if (store_info->alias_set) | |
2507 | { | |
2508 | int index = get_bitmap_index (clear_alias_group, | |
2509 | store_info->alias_set); | |
2510 | if (index != 0) | |
2511 | { | |
2512 | bitmap_set_bit (gen, index); | |
2513 | if (kill) | |
2514 | bitmap_clear_bit (kill, index); | |
2515 | } | |
2516 | } | |
2517 | store_info = store_info->next; | |
2518 | } | |
2519 | } | |
2520 | ||
2521 | ||
2522 | /* Process the READ_INFOs into the bitmaps into GEN and KILL. KILL | |
2523 | may be NULL. */ | |
2524 | ||
2525 | static void | |
2526 | scan_reads_nospill (insn_info_t insn_info, bitmap gen, bitmap kill) | |
2527 | { | |
2528 | read_info_t read_info = insn_info->read_rec; | |
2529 | int i; | |
2530 | group_info_t group; | |
2531 | ||
16bf64db | 2532 | /* If this insn reads the frame, kill all the frame related stores. */ |
2533 | if (insn_info->frame_read) | |
2534 | { | |
2535 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) | |
2536 | if (group->process_globally && group->frame_related) | |
2537 | { | |
2538 | if (kill) | |
2539 | bitmap_ior_into (kill, group->group_kill); | |
2540 | bitmap_and_compl_into (gen, group->group_kill); | |
2541 | } | |
2542 | } | |
2543 | ||
3072d30e | 2544 | while (read_info) |
2545 | { | |
2546 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) | |
2547 | { | |
2548 | if (group->process_globally) | |
2549 | { | |
2550 | if (i == read_info->group_id) | |
2551 | { | |
2552 | if (read_info->begin > read_info->end) | |
2553 | { | |
2554 | /* Begin > end for block mode reads. */ | |
2555 | if (kill) | |
2556 | bitmap_ior_into (kill, group->group_kill); | |
2557 | bitmap_and_compl_into (gen, group->group_kill); | |
2558 | } | |
2559 | else | |
2560 | { | |
2561 | /* The groups are the same, just process the | |
2562 | offsets. */ | |
2563 | HOST_WIDE_INT j; | |
2564 | for (j = read_info->begin; j < read_info->end; j++) | |
2565 | { | |
2566 | int index = get_bitmap_index (group, j); | |
2567 | if (index != 0) | |
2568 | { | |
2569 | if (kill) | |
2570 | bitmap_set_bit (kill, index); | |
2571 | bitmap_clear_bit (gen, index); | |
2572 | } | |
2573 | } | |
2574 | } | |
2575 | } | |
2576 | else | |
2577 | { | |
2578 | /* The groups are different, if the alias sets | |
2579 | conflict, clear the entire group. We only need | |
2580 | to apply this test if the read_info is a cselib | |
2581 | read. Anything with a constant base cannot alias | |
2582 | something else with a different constant | |
2583 | base. */ | |
2584 | if ((read_info->group_id < 0) | |
2585 | && canon_true_dependence (group->base_mem, | |
2586 | QImode, | |
2587 | group->canon_base_mem, | |
2588 | read_info->mem, rtx_varies_p)) | |
2589 | { | |
2590 | if (kill) | |
2591 | bitmap_ior_into (kill, group->group_kill); | |
2592 | bitmap_and_compl_into (gen, group->group_kill); | |
2593 | } | |
2594 | } | |
2595 | } | |
2596 | } | |
2597 | ||
2598 | read_info = read_info->next; | |
2599 | } | |
2600 | } | |
2601 | ||
2602 | /* Process the READ_INFOs into the bitmaps into GEN and KILL. KILL | |
2603 | may be NULL. */ | |
2604 | ||
2605 | static void | |
2606 | scan_reads_spill (read_info_t read_info, bitmap gen, bitmap kill) | |
2607 | { | |
2608 | while (read_info) | |
2609 | { | |
2610 | if (read_info->alias_set) | |
2611 | { | |
2612 | int index = get_bitmap_index (clear_alias_group, | |
2613 | read_info->alias_set); | |
2614 | if (index != 0) | |
2615 | { | |
2616 | if (kill) | |
2617 | bitmap_set_bit (kill, index); | |
2618 | bitmap_clear_bit (gen, index); | |
2619 | } | |
2620 | } | |
2621 | ||
2622 | read_info = read_info->next; | |
2623 | } | |
2624 | } | |
2625 | ||
2626 | ||
2627 | /* Return the insn in BB_INFO before the first wild read or if there | |
2628 | are no wild reads in the block, return the last insn. */ | |
2629 | ||
2630 | static insn_info_t | |
2631 | find_insn_before_first_wild_read (bb_info_t bb_info) | |
2632 | { | |
2633 | insn_info_t insn_info = bb_info->last_insn; | |
2634 | insn_info_t last_wild_read = NULL; | |
2635 | ||
2636 | while (insn_info) | |
2637 | { | |
2638 | if (insn_info->wild_read) | |
2639 | { | |
2640 | last_wild_read = insn_info->prev_insn; | |
2641 | /* Block starts with wild read. */ | |
2642 | if (!last_wild_read) | |
2643 | return NULL; | |
2644 | } | |
2645 | ||
2646 | insn_info = insn_info->prev_insn; | |
2647 | } | |
2648 | ||
2649 | if (last_wild_read) | |
2650 | return last_wild_read; | |
2651 | else | |
2652 | return bb_info->last_insn; | |
2653 | } | |
2654 | ||
2655 | ||
2656 | /* Scan the insns in BB_INFO starting at PTR and going to the top of | |
2657 | the block in order to build the gen and kill sets for the block. | |
2658 | We start at ptr which may be the last insn in the block or may be | |
2659 | the first insn with a wild read. In the latter case we are able to | |
2660 | skip the rest of the block because it just does not matter: | |
2661 | anything that happens is hidden by the wild read. */ | |
2662 | ||
2663 | static void | |
2664 | dse_step3_scan (bool for_spills, basic_block bb) | |
2665 | { | |
2666 | bb_info_t bb_info = bb_table[bb->index]; | |
2667 | insn_info_t insn_info; | |
2668 | ||
2669 | if (for_spills) | |
2670 | /* There are no wild reads in the spill case. */ | |
2671 | insn_info = bb_info->last_insn; | |
2672 | else | |
2673 | insn_info = find_insn_before_first_wild_read (bb_info); | |
2674 | ||
2675 | /* In the spill case or in the no_spill case if there is no wild | |
2676 | read in the block, we will need a kill set. */ | |
2677 | if (insn_info == bb_info->last_insn) | |
2678 | { | |
2679 | if (bb_info->kill) | |
2680 | bitmap_clear (bb_info->kill); | |
2681 | else | |
2682 | bb_info->kill = BITMAP_ALLOC (NULL); | |
2683 | } | |
2684 | else | |
2685 | if (bb_info->kill) | |
2686 | BITMAP_FREE (bb_info->kill); | |
2687 | ||
2688 | while (insn_info) | |
2689 | { | |
2690 | /* There may have been code deleted by the dce pass run before | |
2691 | this phase. */ | |
2692 | if (insn_info->insn && INSN_P (insn_info->insn)) | |
2693 | { | |
2694 | /* Process the read(s) last. */ | |
2695 | if (for_spills) | |
2696 | { | |
2697 | scan_stores_spill (insn_info->store_rec, bb_info->gen, bb_info->kill); | |
2698 | scan_reads_spill (insn_info->read_rec, bb_info->gen, bb_info->kill); | |
2699 | } | |
2700 | else | |
2701 | { | |
2702 | scan_stores_nospill (insn_info->store_rec, bb_info->gen, bb_info->kill); | |
2703 | scan_reads_nospill (insn_info, bb_info->gen, bb_info->kill); | |
2704 | } | |
2705 | } | |
2706 | ||
2707 | insn_info = insn_info->prev_insn; | |
2708 | } | |
2709 | } | |
2710 | ||
2711 | ||
2712 | /* Set the gen set of the exit block, and also any block with no | |
2713 | successors that does not have a wild read. */ | |
2714 | ||
2715 | static void | |
2716 | dse_step3_exit_block_scan (bb_info_t bb_info) | |
2717 | { | |
2718 | /* The gen set is all 0's for the exit block except for the | |
2719 | frame_pointer_group. */ | |
2720 | ||
2721 | if (stores_off_frame_dead_at_return) | |
2722 | { | |
2723 | unsigned int i; | |
2724 | group_info_t group; | |
2725 | ||
2726 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) | |
2727 | { | |
2728 | if (group->process_globally && group->frame_related) | |
2729 | bitmap_ior_into (bb_info->gen, group->group_kill); | |
2730 | } | |
2731 | } | |
2732 | } | |
2733 | ||
2734 | ||
2735 | /* Find all of the blocks that are not backwards reachable from the | |
2736 | exit block or any block with no successors (BB). These are the | |
2737 | infinite loops or infinite self loops. These blocks will still | |
2738 | have their bits set in UNREACHABLE_BLOCKS. */ | |
2739 | ||
2740 | static void | |
2741 | mark_reachable_blocks (sbitmap unreachable_blocks, basic_block bb) | |
2742 | { | |
2743 | edge e; | |
2744 | edge_iterator ei; | |
2745 | ||
2746 | if (TEST_BIT (unreachable_blocks, bb->index)) | |
2747 | { | |
2748 | RESET_BIT (unreachable_blocks, bb->index); | |
2749 | FOR_EACH_EDGE (e, ei, bb->preds) | |
2750 | { | |
2751 | mark_reachable_blocks (unreachable_blocks, e->src); | |
2752 | } | |
2753 | } | |
2754 | } | |
2755 | ||
2756 | /* Build the transfer functions for the function. */ | |
2757 | ||
2758 | static void | |
2759 | dse_step3 (bool for_spills) | |
2760 | { | |
2761 | basic_block bb; | |
2762 | sbitmap unreachable_blocks = sbitmap_alloc (last_basic_block); | |
2763 | sbitmap_iterator sbi; | |
2764 | bitmap all_ones = NULL; | |
2765 | unsigned int i; | |
2766 | ||
2767 | sbitmap_ones (unreachable_blocks); | |
2768 | ||
2769 | FOR_ALL_BB (bb) | |
2770 | { | |
2771 | bb_info_t bb_info = bb_table[bb->index]; | |
2772 | if (bb_info->gen) | |
2773 | bitmap_clear (bb_info->gen); | |
2774 | else | |
2775 | bb_info->gen = BITMAP_ALLOC (NULL); | |
2776 | ||
2777 | if (bb->index == ENTRY_BLOCK) | |
2778 | ; | |
2779 | else if (bb->index == EXIT_BLOCK) | |
2780 | dse_step3_exit_block_scan (bb_info); | |
2781 | else | |
2782 | dse_step3_scan (for_spills, bb); | |
2783 | if (EDGE_COUNT (bb->succs) == 0) | |
2784 | mark_reachable_blocks (unreachable_blocks, bb); | |
2785 | ||
2786 | /* If this is the second time dataflow is run, delete the old | |
2787 | sets. */ | |
2788 | if (bb_info->in) | |
2789 | BITMAP_FREE (bb_info->in); | |
2790 | if (bb_info->out) | |
2791 | BITMAP_FREE (bb_info->out); | |
2792 | } | |
2793 | ||
2794 | /* For any block in an infinite loop, we must initialize the out set | |
2795 | to all ones. This could be expensive, but almost never occurs in | |
2796 | practice. However, it is common in regression tests. */ | |
2797 | EXECUTE_IF_SET_IN_SBITMAP (unreachable_blocks, 0, i, sbi) | |
2798 | { | |
2799 | if (bitmap_bit_p (all_blocks, i)) | |
2800 | { | |
2801 | bb_info_t bb_info = bb_table[i]; | |
2802 | if (!all_ones) | |
2803 | { | |
2804 | unsigned int j; | |
2805 | group_info_t group; | |
2806 | ||
2807 | all_ones = BITMAP_ALLOC (NULL); | |
2808 | for (j = 0; VEC_iterate (group_info_t, rtx_group_vec, j, group); j++) | |
2809 | bitmap_ior_into (all_ones, group->group_kill); | |
2810 | } | |
2811 | if (!bb_info->out) | |
2812 | { | |
2813 | bb_info->out = BITMAP_ALLOC (NULL); | |
2814 | bitmap_copy (bb_info->out, all_ones); | |
2815 | } | |
2816 | } | |
2817 | } | |
2818 | ||
2819 | if (all_ones) | |
2820 | BITMAP_FREE (all_ones); | |
2821 | sbitmap_free (unreachable_blocks); | |
2822 | } | |
2823 | ||
2824 | ||
2825 | \f | |
2826 | /*---------------------------------------------------------------------------- | |
2827 | Fourth step. | |
2828 | ||
2829 | Solve the bitvector equations. | |
2830 | ----------------------------------------------------------------------------*/ | |
2831 | ||
2832 | ||
2833 | /* Confluence function for blocks with no successors. Create an out | |
2834 | set from the gen set of the exit block. This block logically has | |
2835 | the exit block as a successor. */ | |
2836 | ||
2837 | ||
2838 | ||
2839 | static void | |
2840 | dse_confluence_0 (basic_block bb) | |
2841 | { | |
2842 | bb_info_t bb_info = bb_table[bb->index]; | |
2843 | ||
2844 | if (bb->index == EXIT_BLOCK) | |
2845 | return; | |
2846 | ||
2847 | if (!bb_info->out) | |
2848 | { | |
2849 | bb_info->out = BITMAP_ALLOC (NULL); | |
2850 | bitmap_copy (bb_info->out, bb_table[EXIT_BLOCK]->gen); | |
2851 | } | |
2852 | } | |
2853 | ||
2854 | /* Propagate the information from the in set of the dest of E to the | |
2855 | out set of the src of E. If the various in or out sets are not | |
2856 | there, that means they are all ones. */ | |
2857 | ||
2858 | static void | |
2859 | dse_confluence_n (edge e) | |
2860 | { | |
2861 | bb_info_t src_info = bb_table[e->src->index]; | |
2862 | bb_info_t dest_info = bb_table[e->dest->index]; | |
2863 | ||
2864 | if (dest_info->in) | |
2865 | { | |
2866 | if (src_info->out) | |
2867 | bitmap_and_into (src_info->out, dest_info->in); | |
2868 | else | |
2869 | { | |
2870 | src_info->out = BITMAP_ALLOC (NULL); | |
2871 | bitmap_copy (src_info->out, dest_info->in); | |
2872 | } | |
2873 | } | |
2874 | } | |
2875 | ||
2876 | ||
2877 | /* Propagate the info from the out to the in set of BB_INDEX's basic | |
2878 | block. There are three cases: | |
2879 | ||
2880 | 1) The block has no kill set. In this case the kill set is all | |
2881 | ones. It does not matter what the out set of the block is, none of | |
2882 | the info can reach the top. The only thing that reaches the top is | |
2883 | the gen set and we just copy the set. | |
2884 | ||
2885 | 2) There is a kill set but no out set and bb has successors. In | |
2886 | this case we just return. Eventually an out set will be created and | |
2887 | it is better to wait than to create a set of ones. | |
2888 | ||
2889 | 3) There is both a kill and out set. We apply the obvious transfer | |
2890 | function. | |
2891 | */ | |
2892 | ||
2893 | static bool | |
2894 | dse_transfer_function (int bb_index) | |
2895 | { | |
2896 | bb_info_t bb_info = bb_table[bb_index]; | |
2897 | ||
2898 | if (bb_info->kill) | |
2899 | { | |
2900 | if (bb_info->out) | |
2901 | { | |
2902 | /* Case 3 above. */ | |
2903 | if (bb_info->in) | |
2904 | return bitmap_ior_and_compl (bb_info->in, bb_info->gen, | |
2905 | bb_info->out, bb_info->kill); | |
2906 | else | |
2907 | { | |
2908 | bb_info->in = BITMAP_ALLOC (NULL); | |
2909 | bitmap_ior_and_compl (bb_info->in, bb_info->gen, | |
2910 | bb_info->out, bb_info->kill); | |
2911 | return true; | |
2912 | } | |
2913 | } | |
2914 | else | |
2915 | /* Case 2 above. */ | |
2916 | return false; | |
2917 | } | |
2918 | else | |
2919 | { | |
2920 | /* Case 1 above. If there is already an in set, nothing | |
2921 | happens. */ | |
2922 | if (bb_info->in) | |
2923 | return false; | |
2924 | else | |
2925 | { | |
2926 | bb_info->in = BITMAP_ALLOC (NULL); | |
2927 | bitmap_copy (bb_info->in, bb_info->gen); | |
2928 | return true; | |
2929 | } | |
2930 | } | |
2931 | } | |
2932 | ||
2933 | /* Solve the dataflow equations. */ | |
2934 | ||
2935 | static void | |
2936 | dse_step4 (void) | |
2937 | { | |
2938 | df_simple_dataflow (DF_BACKWARD, NULL, dse_confluence_0, | |
2939 | dse_confluence_n, dse_transfer_function, | |
2940 | all_blocks, df_get_postorder (DF_BACKWARD), | |
2941 | df_get_n_blocks (DF_BACKWARD)); | |
2942 | if (dump_file) | |
2943 | { | |
2944 | basic_block bb; | |
2945 | ||
2946 | fprintf (dump_file, "\n\n*** Global dataflow info after analysis.\n"); | |
2947 | FOR_ALL_BB (bb) | |
2948 | { | |
2949 | bb_info_t bb_info = bb_table[bb->index]; | |
2950 | ||
2951 | df_print_bb_index (bb, dump_file); | |
2952 | if (bb_info->in) | |
2953 | bitmap_print (dump_file, bb_info->in, " in: ", "\n"); | |
2954 | else | |
2955 | fprintf (dump_file, " in: *MISSING*\n"); | |
2956 | if (bb_info->gen) | |
2957 | bitmap_print (dump_file, bb_info->gen, " gen: ", "\n"); | |
2958 | else | |
2959 | fprintf (dump_file, " gen: *MISSING*\n"); | |
2960 | if (bb_info->kill) | |
2961 | bitmap_print (dump_file, bb_info->kill, " kill: ", "\n"); | |
2962 | else | |
2963 | fprintf (dump_file, " kill: *MISSING*\n"); | |
2964 | if (bb_info->out) | |
2965 | bitmap_print (dump_file, bb_info->out, " out: ", "\n"); | |
2966 | else | |
2967 | fprintf (dump_file, " out: *MISSING*\n\n"); | |
2968 | } | |
2969 | } | |
2970 | } | |
2971 | ||
2972 | ||
2973 | \f | |
2974 | /*---------------------------------------------------------------------------- | |
2975 | Fifth step. | |
2976 | ||
bef304b8 | 2977 | Delete the stores that can only be deleted using the global information. |
3072d30e | 2978 | ----------------------------------------------------------------------------*/ |
2979 | ||
2980 | ||
2981 | static void | |
2982 | dse_step5_nospill (void) | |
2983 | { | |
2984 | basic_block bb; | |
2985 | FOR_EACH_BB (bb) | |
2986 | { | |
2987 | bb_info_t bb_info = bb_table[bb->index]; | |
2988 | insn_info_t insn_info = bb_info->last_insn; | |
2989 | bitmap v = bb_info->out; | |
2990 | ||
2991 | while (insn_info) | |
2992 | { | |
2993 | bool deleted = false; | |
2994 | if (dump_file && insn_info->insn) | |
2995 | { | |
2996 | fprintf (dump_file, "starting to process insn %d\n", | |
2997 | INSN_UID (insn_info->insn)); | |
2998 | bitmap_print (dump_file, v, " v: ", "\n"); | |
2999 | } | |
3000 | ||
3001 | /* There may have been code deleted by the dce pass run before | |
3002 | this phase. */ | |
3003 | if (insn_info->insn | |
3004 | && INSN_P (insn_info->insn) | |
3005 | && (!insn_info->cannot_delete) | |
3006 | && (!bitmap_empty_p (v))) | |
3007 | { | |
3008 | store_info_t store_info = insn_info->store_rec; | |
3009 | ||
3010 | /* Try to delete the current insn. */ | |
3011 | deleted = true; | |
3012 | ||
3013 | /* Skip the clobbers. */ | |
3014 | while (!store_info->is_set) | |
3015 | store_info = store_info->next; | |
3016 | ||
3017 | if (store_info->alias_set) | |
3018 | deleted = false; | |
3019 | else | |
3020 | { | |
3021 | HOST_WIDE_INT i; | |
3022 | group_info_t group_info | |
3023 | = VEC_index (group_info_t, rtx_group_vec, store_info->group_id); | |
3024 | ||
3025 | for (i = store_info->begin; i < store_info->end; i++) | |
3026 | { | |
3027 | int index = get_bitmap_index (group_info, i); | |
3028 | ||
3029 | if (dump_file) | |
3030 | fprintf (dump_file, "i = %d, index = %d\n", (int)i, index); | |
3031 | if (index == 0 || !bitmap_bit_p (v, index)) | |
3032 | { | |
3033 | if (dump_file) | |
3034 | fprintf (dump_file, "failing at i = %d\n", (int)i); | |
3035 | deleted = false; | |
3036 | break; | |
3037 | } | |
3038 | } | |
3039 | } | |
3040 | if (deleted) | |
3041 | { | |
3042 | if (dbg_cnt (dse)) | |
3043 | { | |
3044 | check_for_inc_dec (insn_info->insn); | |
3045 | delete_insn (insn_info->insn); | |
3046 | insn_info->insn = NULL; | |
3047 | globally_deleted++; | |
3048 | } | |
3049 | } | |
3050 | } | |
3051 | /* We do want to process the local info if the insn was | |
6dfdc153 | 3052 | deleted. For instance, if the insn did a wild read, we |
3072d30e | 3053 | no longer need to trash the info. */ |
3054 | if (insn_info->insn | |
3055 | && INSN_P (insn_info->insn) | |
3056 | && (!deleted)) | |
3057 | { | |
3058 | scan_stores_nospill (insn_info->store_rec, v, NULL); | |
3059 | if (insn_info->wild_read) | |
3060 | { | |
3061 | if (dump_file) | |
3062 | fprintf (dump_file, "wild read\n"); | |
3063 | bitmap_clear (v); | |
3064 | } | |
3065 | else if (insn_info->read_rec) | |
3066 | { | |
3067 | if (dump_file) | |
3068 | fprintf (dump_file, "regular read\n"); | |
3069 | scan_reads_nospill (insn_info, v, NULL); | |
3070 | } | |
3071 | } | |
3072 | ||
3073 | insn_info = insn_info->prev_insn; | |
3074 | } | |
3075 | } | |
3076 | } | |
3077 | ||
3078 | ||
3079 | static void | |
3080 | dse_step5_spill (void) | |
3081 | { | |
3082 | basic_block bb; | |
3083 | FOR_EACH_BB (bb) | |
3084 | { | |
3085 | bb_info_t bb_info = bb_table[bb->index]; | |
3086 | insn_info_t insn_info = bb_info->last_insn; | |
3087 | bitmap v = bb_info->out; | |
3088 | ||
3089 | while (insn_info) | |
3090 | { | |
3091 | bool deleted = false; | |
3092 | /* There may have been code deleted by the dce pass run before | |
3093 | this phase. */ | |
3094 | if (insn_info->insn | |
3095 | && INSN_P (insn_info->insn) | |
3096 | && (!insn_info->cannot_delete) | |
3097 | && (!bitmap_empty_p (v))) | |
3098 | { | |
3099 | /* Try to delete the current insn. */ | |
3100 | store_info_t store_info = insn_info->store_rec; | |
3101 | deleted = true; | |
3102 | ||
3103 | while (store_info) | |
3104 | { | |
3105 | if (store_info->alias_set) | |
3106 | { | |
3107 | int index = get_bitmap_index (clear_alias_group, | |
3108 | store_info->alias_set); | |
3109 | if (index == 0 || !bitmap_bit_p (v, index)) | |
3110 | { | |
3111 | deleted = false; | |
3112 | break; | |
3113 | } | |
3114 | } | |
3115 | else | |
3116 | deleted = false; | |
3117 | store_info = store_info->next; | |
3118 | } | |
3119 | if (deleted && dbg_cnt (dse)) | |
3120 | { | |
3121 | if (dump_file) | |
3122 | fprintf (dump_file, "Spill deleting insn %d\n", | |
3123 | INSN_UID (insn_info->insn)); | |
3124 | check_for_inc_dec (insn_info->insn); | |
3125 | delete_insn (insn_info->insn); | |
3126 | spill_deleted++; | |
3127 | insn_info->insn = NULL; | |
3128 | } | |
3129 | } | |
3130 | ||
3131 | if (insn_info->insn | |
3132 | && INSN_P (insn_info->insn) | |
3133 | && (!deleted)) | |
3134 | { | |
3135 | scan_stores_spill (insn_info->store_rec, v, NULL); | |
3136 | scan_reads_spill (insn_info->read_rec, v, NULL); | |
3137 | } | |
3138 | ||
3139 | insn_info = insn_info->prev_insn; | |
3140 | } | |
3141 | } | |
3142 | } | |
3143 | ||
3144 | ||
3145 | \f | |
3146 | /*---------------------------------------------------------------------------- | |
3147 | Sixth step. | |
3148 | ||
3149 | Destroy everything left standing. | |
3150 | ----------------------------------------------------------------------------*/ | |
3151 | ||
3152 | static void | |
3153 | dse_step6 (bool global_done) | |
3154 | { | |
3155 | unsigned int i; | |
3156 | group_info_t group; | |
3157 | basic_block bb; | |
3158 | ||
ce299759 | 3159 | for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++) |
3072d30e | 3160 | { |
ce299759 | 3161 | free (group->offset_map_n); |
3162 | free (group->offset_map_p); | |
3163 | BITMAP_FREE (group->store1_n); | |
3164 | BITMAP_FREE (group->store1_p); | |
3165 | BITMAP_FREE (group->store2_n); | |
3166 | BITMAP_FREE (group->store2_p); | |
3167 | BITMAP_FREE (group->group_kill); | |
3072d30e | 3168 | } |
3169 | ||
ce299759 | 3170 | if (global_done) |
3171 | FOR_ALL_BB (bb) | |
3172 | { | |
3173 | bb_info_t bb_info = bb_table[bb->index]; | |
3174 | BITMAP_FREE (bb_info->gen); | |
3175 | if (bb_info->kill) | |
3176 | BITMAP_FREE (bb_info->kill); | |
3177 | if (bb_info->in) | |
3178 | BITMAP_FREE (bb_info->in); | |
3179 | if (bb_info->out) | |
3180 | BITMAP_FREE (bb_info->out); | |
3181 | } | |
3182 | ||
3072d30e | 3183 | if (clear_alias_sets) |
3184 | { | |
3185 | BITMAP_FREE (clear_alias_sets); | |
3186 | BITMAP_FREE (disqualified_clear_alias_sets); | |
3187 | free_alloc_pool (clear_alias_mode_pool); | |
3188 | htab_delete (clear_alias_mode_table); | |
3189 | } | |
3190 | ||
3191 | end_alias_analysis (); | |
3192 | free (bb_table); | |
3193 | htab_delete (rtx_group_table); | |
3194 | VEC_free (group_info_t, heap, rtx_group_vec); | |
3195 | BITMAP_FREE (all_blocks); | |
3196 | BITMAP_FREE (scratch); | |
3197 | ||
3198 | free_alloc_pool (rtx_store_info_pool); | |
3199 | free_alloc_pool (read_info_pool); | |
3200 | free_alloc_pool (insn_info_pool); | |
3201 | free_alloc_pool (bb_info_pool); | |
3202 | free_alloc_pool (rtx_group_info_pool); | |
3203 | free_alloc_pool (deferred_change_pool); | |
3204 | } | |
3205 | ||
3206 | ||
3072d30e | 3207 | /* ------------------------------------------------------------------------- |
3208 | DSE | |
3209 | ------------------------------------------------------------------------- */ | |
3210 | ||
3211 | /* Callback for running pass_rtl_dse. */ | |
3212 | ||
3213 | static unsigned int | |
3214 | rest_of_handle_dse (void) | |
3215 | { | |
3216 | bool did_global = false; | |
3217 | ||
3218 | df_set_flags (DF_DEFER_INSN_RESCAN); | |
3219 | ||
3220 | dse_step0 (); | |
3221 | dse_step1 (); | |
3222 | dse_step2_init (); | |
3223 | if (dse_step2_nospill ()) | |
3224 | { | |
3225 | df_set_flags (DF_LR_RUN_DCE); | |
3226 | df_analyze (); | |
3227 | did_global = true; | |
3228 | if (dump_file) | |
3229 | fprintf (dump_file, "doing global processing\n"); | |
3230 | dse_step3 (false); | |
3231 | dse_step4 (); | |
3232 | dse_step5_nospill (); | |
3233 | } | |
3234 | ||
3235 | /* For the instance of dse that runs after reload, we make a special | |
3236 | pass to process the spills. These are special in that they are | |
3237 | totally transparent, i.e, there is no aliasing issues that need | |
3238 | to be considered. This means that the wild reads that kill | |
3239 | everything else do not apply here. */ | |
3240 | if (clear_alias_sets && dse_step2_spill ()) | |
3241 | { | |
3242 | if (!did_global) | |
3243 | { | |
3244 | df_set_flags (DF_LR_RUN_DCE); | |
3245 | df_analyze (); | |
3246 | } | |
3247 | did_global = true; | |
3248 | if (dump_file) | |
3249 | fprintf (dump_file, "doing global spill processing\n"); | |
3250 | dse_step3 (true); | |
3251 | dse_step4 (); | |
3252 | dse_step5_spill (); | |
3253 | } | |
3254 | ||
3255 | dse_step6 (did_global); | |
3256 | ||
3257 | if (dump_file) | |
3258 | fprintf (dump_file, "dse: local deletions = %d, global deletions = %d, spill deletions = %d\n", | |
3259 | locally_deleted, globally_deleted, spill_deleted); | |
3260 | return 0; | |
3261 | } | |
3262 | ||
3263 | static bool | |
3264 | gate_dse (void) | |
3265 | { | |
4ff06051 | 3266 | return gate_dse1 () || gate_dse2 (); |
3267 | } | |
3268 | ||
3269 | static bool | |
3270 | gate_dse1 (void) | |
3271 | { | |
3272 | return optimize > 0 && flag_dse | |
3273 | && dbg_cnt (dse1); | |
3274 | } | |
3275 | ||
3276 | static bool | |
3277 | gate_dse2 (void) | |
3278 | { | |
3279 | return optimize > 0 && flag_dse | |
3280 | && dbg_cnt (dse2); | |
3072d30e | 3281 | } |
3282 | ||
20099e35 | 3283 | struct rtl_opt_pass pass_rtl_dse1 = |
3072d30e | 3284 | { |
20099e35 | 3285 | { |
3286 | RTL_PASS, | |
3072d30e | 3287 | "dse1", /* name */ |
4ff06051 | 3288 | gate_dse1, /* gate */ |
3072d30e | 3289 | rest_of_handle_dse, /* execute */ |
3290 | NULL, /* sub */ | |
3291 | NULL, /* next */ | |
3292 | 0, /* static_pass_number */ | |
3293 | TV_DSE1, /* tv_id */ | |
3294 | 0, /* properties_required */ | |
3295 | 0, /* properties_provided */ | |
3296 | 0, /* properties_destroyed */ | |
3297 | 0, /* todo_flags_start */ | |
3298 | TODO_dump_func | | |
0806b508 | 3299 | TODO_df_finish | TODO_verify_rtl_sharing | |
20099e35 | 3300 | TODO_ggc_collect /* todo_flags_finish */ |
3301 | } | |
3072d30e | 3302 | }; |
3303 | ||
20099e35 | 3304 | struct rtl_opt_pass pass_rtl_dse2 = |
3072d30e | 3305 | { |
20099e35 | 3306 | { |
3307 | RTL_PASS, | |
3072d30e | 3308 | "dse2", /* name */ |
4ff06051 | 3309 | gate_dse2, /* gate */ |
3072d30e | 3310 | rest_of_handle_dse, /* execute */ |
3311 | NULL, /* sub */ | |
3312 | NULL, /* next */ | |
3313 | 0, /* static_pass_number */ | |
3314 | TV_DSE2, /* tv_id */ | |
3315 | 0, /* properties_required */ | |
3316 | 0, /* properties_provided */ | |
3317 | 0, /* properties_destroyed */ | |
3318 | 0, /* todo_flags_start */ | |
3319 | TODO_dump_func | | |
0806b508 | 3320 | TODO_df_finish | TODO_verify_rtl_sharing | |
20099e35 | 3321 | TODO_ggc_collect /* todo_flags_finish */ |
3322 | } | |
3072d30e | 3323 | }; |