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fe3ad572 1/* Perform branch target register load optimizations.
1194fc79 2 Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
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3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 2, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING. If not, write to the Free
18Software Foundation, 59 Temple Place - Suite 330, Boston, MA
1902111-1307, USA. */
20
21#include "config.h"
22#include "system.h"
23#include "coretypes.h"
24#include "tm.h"
25#include "bitmap.h"
26#include "sbitmap.h"
27#include "rtl.h"
28#include "hard-reg-set.h"
29#include "basic-block.h"
30#include "regs.h"
31#include "obstack.h"
32#include "fibheap.h"
33#include "output.h"
34#include "target.h"
35#include "expr.h"
36#include "flags.h"
37#include "insn-attr.h"
38#include "function.h"
1194fc79 39#include "except.h"
8f7193b8 40#include "tm_p.h"
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41
42/* Target register optimizations - these are performed after reload. */
43
44typedef struct btr_def_group_s
45{
46 struct btr_def_group_s *next;
47 rtx src;
48 struct btr_def_s *members;
49} *btr_def_group;
50
51typedef struct btr_user_s
52{
53 struct btr_user_s *next;
54 basic_block bb;
55 int luid;
56 rtx insn;
57 /* If INSN has a single use of a single branch register, then
58 USE points to it within INSN. If there is more than
59 one branch register use, or the use is in some way ambiguous,
60 then USE is NULL. */
61 rtx use;
62 int n_reaching_defs;
63 int first_reaching_def;
64 char other_use_this_block;
65} *btr_user;
66
67/* btr_def structs appear on three lists:
68 1. A list of all btr_def structures (head is
69 ALL_BTR_DEFS, linked by the NEXT field).
70 2. A list of branch reg definitions per basic block (head is
71 BB_BTR_DEFS[i], linked by the NEXT_THIS_BB field).
72 3. A list of all branch reg definitions belonging to the same
73 group (head is in a BTR_DEF_GROUP struct, linked by
74 NEXT_THIS_GROUP field). */
75
76typedef struct btr_def_s
77{
78 struct btr_def_s *next_this_bb;
79 struct btr_def_s *next_this_group;
80 basic_block bb;
81 int luid;
82 rtx insn;
83 int btr;
84 int cost;
85 /* For a branch register setting insn that has a constant
86 source (i.e. a label), group links together all the
87 insns with the same source. For other branch register
88 setting insns, group is NULL. */
89 btr_def_group group;
90 btr_user uses;
91 /* If this def has a reaching use which is not a simple use
92 in a branch instruction, then has_ambiguous_use will be true,
f9da5064 93 and we will not attempt to migrate this definition. */
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94 char has_ambiguous_use;
95 /* live_range is an approximation to the true live range for this
96 def/use web, because it records the set of blocks that contain
97 the live range. There could be other live ranges for the same
98 branch register in that set of blocks, either in the block
99 containing the def (before the def), or in a block containing
100 a use (after the use). If there are such other live ranges, then
101 other_btr_uses_before_def or other_btr_uses_after_use must be set true
71c0e7fc 102 as appropriate. */
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103 char other_btr_uses_before_def;
104 char other_btr_uses_after_use;
105 bitmap live_range;
106} *btr_def;
107
108static int issue_rate;
109
110static int basic_block_freq (basic_block);
111static int insn_sets_btr_p (rtx, int, int *);
112static rtx *find_btr_use (rtx);
113static int btr_referenced_p (rtx, rtx *);
114static int find_btr_reference (rtx *, void *);
115static void find_btr_def_group (btr_def_group *, btr_def);
116static btr_def add_btr_def (fibheap_t, basic_block, int, rtx,
117 unsigned int, int, btr_def_group *);
118static btr_user new_btr_user (basic_block, int, rtx);
119static void dump_hard_reg_set (HARD_REG_SET);
120static void dump_btrs_live (int);
121static void note_other_use_this_block (unsigned int, btr_user);
122static void compute_defs_uses_and_gen (fibheap_t, btr_def *,btr_user *,
123 sbitmap *, sbitmap *, HARD_REG_SET *);
124static void compute_kill (sbitmap *, sbitmap *, HARD_REG_SET *);
125static void compute_out (sbitmap *bb_out, sbitmap *, sbitmap *, int);
126static void link_btr_uses (btr_def *, btr_user *, sbitmap *, sbitmap *, int);
127static void build_btr_def_use_webs (fibheap_t);
128static int block_at_edge_of_live_range_p (int, btr_def);
129static void clear_btr_from_live_range (btr_def def);
130static void add_btr_to_live_range (btr_def);
131static void augment_live_range (bitmap, HARD_REG_SET *, basic_block,
132 basic_block);
133static int choose_btr (HARD_REG_SET);
134static void combine_btr_defs (btr_def, HARD_REG_SET *);
135static void btr_def_live_range (btr_def, HARD_REG_SET *);
136static void move_btr_def (basic_block, int, btr_def, bitmap, HARD_REG_SET *);
137static int migrate_btr_def (btr_def, int);
138static void migrate_btr_defs (enum reg_class, int);
139static int can_move_up (basic_block, rtx, int);
140static void note_btr_set (rtx, rtx, void *);
141\f
142/* The following code performs code motion of target load instructions
143 (instructions that set branch target registers), to move them
144 forward away from the branch instructions and out of loops (or,
145 more generally, from a more frequently executed place to a less
146 frequently executed place).
147 Moving target load instructions further in front of the branch
148 instruction that uses the target register value means that the hardware
149 has a better chance of preloading the instructions at the branch
150 target by the time the branch is reached. This avoids bubbles
151 when a taken branch needs to flush out the pipeline.
152 Moving target load instructions out of loops means they are executed
153 less frequently. */
154
155/* An obstack to hold the def-use web data structures built up for
156 migrating branch target load instructions. */
157static struct obstack migrate_btrl_obstack;
158
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159/* Array indexed by basic block number, giving the set of registers
160 live in that block. */
161static HARD_REG_SET *btrs_live;
162
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163/* Array indexed by basic block number, giving the set of registers live at
164 the end of that block, including any uses by a final jump insn, if any. */
165static HARD_REG_SET *btrs_live_at_end;
166
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167/* Set of all target registers that we are willing to allocate. */
168static HARD_REG_SET all_btrs;
169
170/* Provide lower and upper bounds for target register numbers, so that
171 we don't need to search through all the hard registers all the time. */
172static int first_btr, last_btr;
173
174
175
1194fc79 176/* Return an estimate of the frequency of execution of block bb. */
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177static int
178basic_block_freq (basic_block bb)
179{
180 return bb->frequency;
181}
182
183static rtx *btr_reference_found;
184
185/* A subroutine of btr_referenced_p, called through for_each_rtx.
186 PREG is a pointer to an rtx that is to be excluded from the
187 traversal. If we find a reference to a target register anywhere
188 else, return 1, and put a pointer to it into btr_reference_found. */
189static int
190find_btr_reference (rtx *px, void *preg)
191{
192 rtx x;
193 int regno, i;
194
195 if (px == preg)
196 return -1;
197 x = *px;
198 if (GET_CODE (x) != REG)
199 return 0;
200 regno = REGNO (x);
66fd46b6 201 for (i = hard_regno_nregs[regno][GET_MODE (x)] - 1; i >= 0; i--)
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202 if (TEST_HARD_REG_BIT (all_btrs, regno+i))
203 {
204 btr_reference_found = px;
205 return 1;
206 }
207 return -1;
208}
209
210/* Return nonzero if X references (sets or reads) any branch target register.
211 If EXCLUDEP is set, disregard any references within the rtx pointed to
212 by it. If returning nonzero, also set btr_reference_found as above. */
213static int
214btr_referenced_p (rtx x, rtx *excludep)
215{
216 return for_each_rtx (&x, find_btr_reference, excludep);
217}
218
219/* Return true if insn is an instruction that sets a target register.
220 if CHECK_CONST is true, only return true if the source is constant.
221 If such a set is found and REGNO is nonzero, assign the register number
222 of the destination register to *REGNO. */
223static int
224insn_sets_btr_p (rtx insn, int check_const, int *regno)
225{
226 rtx set;
227
228 if (GET_CODE (insn) == INSN
229 && (set = single_set (insn)))
230 {
231 rtx dest = SET_DEST (set);
232 rtx src = SET_SRC (set);
233
234 if (GET_CODE (dest) == SUBREG)
235 dest = XEXP (dest, 0);
236
237 if (GET_CODE (dest) == REG
238 && TEST_HARD_REG_BIT (all_btrs, REGNO (dest)))
239 {
240 if (btr_referenced_p (src, NULL))
241 abort();
242 if (!check_const || CONSTANT_P (src))
243 {
244 if (regno)
245 *regno = REGNO (dest);
246 return 1;
247 }
248 }
249 }
250 return 0;
251}
252
71c0e7fc 253/* Find and return a use of a target register within an instruction INSN. */
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254static rtx *
255find_btr_use (rtx insn)
256{
257 return btr_referenced_p (insn, NULL) ? btr_reference_found : NULL;
258}
259
260/* Find the group that the target register definition DEF belongs
261 to in the list starting with *ALL_BTR_DEF_GROUPS. If no such
262 group exists, create one. Add def to the group. */
263static void
264find_btr_def_group (btr_def_group *all_btr_def_groups, btr_def def)
265{
266 if (insn_sets_btr_p (def->insn, 1, NULL))
267 {
268 btr_def_group this_group;
269 rtx def_src = SET_SRC (single_set (def->insn));
270
271 /* ?? This linear search is an efficiency concern, particularly
272 as the search will almost always fail to find a match. */
273 for (this_group = *all_btr_def_groups;
274 this_group != NULL;
275 this_group = this_group->next)
276 if (rtx_equal_p (def_src, this_group->src))
277 break;
278
279 if (!this_group)
280 {
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281 this_group = obstack_alloc (&migrate_btrl_obstack,
282 sizeof (struct btr_def_group_s));
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283 this_group->src = def_src;
284 this_group->members = NULL;
285 this_group->next = *all_btr_def_groups;
286 *all_btr_def_groups = this_group;
287 }
288 def->group = this_group;
289 def->next_this_group = this_group->members;
290 this_group->members = def;
291 }
292 else
293 def->group = NULL;
294}
295
296/* Create a new target register definition structure, for a definition in
297 block BB, instruction INSN, and insert it into ALL_BTR_DEFS. Return
298 the new definition. */
299static btr_def
300add_btr_def (fibheap_t all_btr_defs, basic_block bb, int insn_luid, rtx insn,
301 unsigned int dest_reg, int other_btr_uses_before_def,
302 btr_def_group *all_btr_def_groups)
303{
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304 btr_def this
305 = obstack_alloc (&migrate_btrl_obstack, sizeof (struct btr_def_s));
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306 this->bb = bb;
307 this->luid = insn_luid;
308 this->insn = insn;
309 this->btr = dest_reg;
310 this->cost = basic_block_freq (bb);
311 this->has_ambiguous_use = 0;
312 this->other_btr_uses_before_def = other_btr_uses_before_def;
313 this->other_btr_uses_after_use = 0;
314 this->next_this_bb = NULL;
315 this->next_this_group = NULL;
316 this->uses = NULL;
317 this->live_range = NULL;
318 find_btr_def_group (all_btr_def_groups, this);
319
320 fibheap_insert (all_btr_defs, -this->cost, this);
321
322 if (rtl_dump_file)
323 fprintf (rtl_dump_file,
324 "Found target reg definition: sets %u { bb %d, insn %d }%s priority %d\n",
325 dest_reg, bb->index, INSN_UID (insn), (this->group ? "" : ":not const"),
326 this->cost);
327
328 return this;
329}
330
331/* Create a new target register user structure, for a use in block BB,
332 instruction INSN. Return the new user. */
333static btr_user
334new_btr_user (basic_block bb, int insn_luid, rtx insn)
335{
336 /* This instruction reads target registers. We need
337 to decide whether we can replace all target register
338 uses easily.
339 */
340 rtx *usep = find_btr_use (PATTERN (insn));
341 rtx use;
342 btr_user user = NULL;
343
344 if (usep)
345 {
346 int unambiguous_single_use;
347
348 /* We want to ensure that USE is the only use of a target
349 register in INSN, so that we know that to rewrite INSN to use
350 a different target register, all we have to do is replace USE. */
351 unambiguous_single_use = !btr_referenced_p (PATTERN (insn), usep);
352 if (!unambiguous_single_use)
353 usep = NULL;
354 }
355 use = usep ? *usep : NULL_RTX;
703ad42b 356 user = obstack_alloc (&migrate_btrl_obstack, sizeof (struct btr_user_s));
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357 user->bb = bb;
358 user->luid = insn_luid;
359 user->insn = insn;
360 user->use = use;
361 user->other_use_this_block = 0;
362 user->next = NULL;
363 user->n_reaching_defs = 0;
364 user->first_reaching_def = -1;
365
366 if (rtl_dump_file)
367 {
368 fprintf (rtl_dump_file, "Uses target reg: { bb %d, insn %d }",
369 bb->index, INSN_UID (insn));
370
371 if (user->use)
372 fprintf (rtl_dump_file, ": unambiguous use of reg %d\n",
373 REGNO (user->use));
374 }
375
376 return user;
377}
378
71c0e7fc 379/* Write the contents of S to the dump file. */
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380static void
381dump_hard_reg_set (HARD_REG_SET s)
382{
383 int reg;
384 for (reg = 0; reg < FIRST_PSEUDO_REGISTER; reg++)
385 if (TEST_HARD_REG_BIT (s, reg))
386 fprintf (rtl_dump_file, " %d", reg);
387}
388
71c0e7fc 389/* Write the set of target regs live in block BB to the dump file. */
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390static void
391dump_btrs_live (int bb)
392{
393 fprintf (rtl_dump_file, "BB%d live:", bb);
394 dump_hard_reg_set (btrs_live[bb]);
395 fprintf (rtl_dump_file, "\n");
396}
397
398/* REGNO is the number of a branch target register that is being used or
399 set. USERS_THIS_BB is a list of preceding branch target register users;
400 If any of them use the same register, set their other_use_this_block
401 flag. */
402static void
403note_other_use_this_block (unsigned int regno, btr_user users_this_bb)
404{
405 btr_user user;
406
407 for (user = users_this_bb; user != NULL; user = user->next)
408 if (user->use && REGNO (user->use) == regno)
409 user->other_use_this_block = 1;
410}
411
412typedef struct {
413 btr_user users_this_bb;
414 HARD_REG_SET btrs_written_in_block;
415 HARD_REG_SET btrs_live_in_block;
416 sbitmap bb_gen;
417 sbitmap *btr_defset;
418} defs_uses_info;
419
420/* Called via note_stores or directly to register stores into /
421 clobbers of a branch target register DEST that are not recognized as
422 straightforward definitions. DATA points to information about the
f9da5064 423 current basic block that needs updating. */
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424static void
425note_btr_set (rtx dest, rtx set ATTRIBUTE_UNUSED, void *data)
426{
427 defs_uses_info *info = data;
428 int regno, end_regno;
429
430 if (GET_CODE (dest) != REG)
431 return;
432 regno = REGNO (dest);
66fd46b6 433 end_regno = regno + hard_regno_nregs[regno][GET_MODE (dest)];
fe3ad572
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434 for (; regno < end_regno; regno++)
435 if (TEST_HARD_REG_BIT (all_btrs, regno))
436 {
437 note_other_use_this_block (regno, info->users_this_bb);
438 SET_HARD_REG_BIT (info->btrs_written_in_block, regno);
439 SET_HARD_REG_BIT (info->btrs_live_in_block, regno);
440 sbitmap_difference (info->bb_gen, info->bb_gen,
441 info->btr_defset[regno - first_btr]);
442 }
443}
444
445static void
446compute_defs_uses_and_gen (fibheap_t all_btr_defs, btr_def *def_array,
447 btr_user *use_array, sbitmap *btr_defset,
448 sbitmap *bb_gen, HARD_REG_SET *btrs_written)
449{
450 /* Scan the code building up the set of all defs and all uses.
451 For each target register, build the set of defs of that register.
452 For each block, calculate the set of target registers
453 written in that block.
454 Also calculate the set of btrs ever live in that block.
455 */
456 int i;
457 int insn_luid = 0;
458 btr_def_group all_btr_def_groups = NULL;
459 defs_uses_info info;
460
461 sbitmap_vector_zero (bb_gen, n_basic_blocks);
462 for (i = 0; i < n_basic_blocks; i++)
463 {
464 basic_block bb = BASIC_BLOCK (i);
465 int reg;
466 btr_def defs_this_bb = NULL;
467 rtx insn;
468 rtx last;
1194fc79 469 int can_throw = 0;
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470
471 info.users_this_bb = NULL;
472 info.bb_gen = bb_gen[i];
473 info.btr_defset = btr_defset;
474
475 CLEAR_HARD_REG_SET (info.btrs_live_in_block);
476 CLEAR_HARD_REG_SET (info.btrs_written_in_block);
477 for (reg = first_btr; reg <= last_btr; reg++)
478 if (TEST_HARD_REG_BIT (all_btrs, reg)
479 && REGNO_REG_SET_P (bb->global_live_at_start, reg))
480 SET_HARD_REG_BIT (info.btrs_live_in_block, reg);
481
a813c111 482 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb));
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483 insn != last;
484 insn = NEXT_INSN (insn), insn_luid++)
485 {
486 if (INSN_P (insn))
487 {
488 int regno;
489 int insn_uid = INSN_UID (insn);
490
491 if (insn_sets_btr_p (insn, 0, &regno))
492 {
493 btr_def def = add_btr_def (
494 all_btr_defs, bb, insn_luid, insn, regno,
495 TEST_HARD_REG_BIT (info.btrs_live_in_block, regno),
496 &all_btr_def_groups);
497
498 def_array[insn_uid] = def;
499 SET_HARD_REG_BIT (info.btrs_written_in_block, regno);
500 SET_HARD_REG_BIT (info.btrs_live_in_block, regno);
501 sbitmap_difference (bb_gen[i], bb_gen[i],
502 btr_defset[regno - first_btr]);
503 SET_BIT (bb_gen[i], insn_uid);
504 def->next_this_bb = defs_this_bb;
505 defs_this_bb = def;
506 SET_BIT (btr_defset[regno - first_btr], insn_uid);
507 note_other_use_this_block (regno, info.users_this_bb);
508 }
509 else
510 {
511 if (btr_referenced_p (PATTERN (insn), NULL))
512 {
513 btr_user user = new_btr_user (bb, insn_luid, insn);
514
515 use_array[insn_uid] = user;
516 if (user->use)
517 SET_HARD_REG_BIT (info.btrs_live_in_block,
518 REGNO (user->use));
519 else
520 {
521 int reg;
522 for (reg = first_btr; reg <= last_btr; reg++)
523 if (TEST_HARD_REG_BIT (all_btrs, reg)
524 && refers_to_regno_p (reg, reg + 1, user->insn,
525 NULL))
526 {
527 note_other_use_this_block (reg,
528 info.users_this_bb);
529 SET_HARD_REG_BIT (info.btrs_live_in_block, reg);
530 }
531 note_stores (PATTERN (insn), note_btr_set, &info);
532 }
533 user->next = info.users_this_bb;
534 info.users_this_bb = user;
535 }
536 if (GET_CODE (insn) == CALL_INSN)
537 {
538 HARD_REG_SET *clobbered = &call_used_reg_set;
539 HARD_REG_SET call_saved;
540 rtx pat = PATTERN (insn);
541 int i;
542
543 /* Check for sibcall. */
544 if (GET_CODE (pat) == PARALLEL)
545 for (i = XVECLEN (pat, 0) - 1; i >= 0; i--)
546 if (GET_CODE (XVECEXP (pat, 0, i)) == RETURN)
547 {
548 COMPL_HARD_REG_SET (call_saved,
549 call_used_reg_set);
550 clobbered = &call_saved;
551 }
1194fc79 552
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553 for (regno = first_btr; regno <= last_btr; regno++)
554 if (TEST_HARD_REG_BIT (*clobbered, regno))
555 note_btr_set (regno_reg_rtx[regno], NULL_RTX, &info);
556 }
557 }
558 }
559 }
560
561 COPY_HARD_REG_SET (btrs_live[i], info.btrs_live_in_block);
562 COPY_HARD_REG_SET (btrs_written[i], info.btrs_written_in_block);
1194fc79
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563
564 REG_SET_TO_HARD_REG_SET (btrs_live_at_end[i], bb->global_live_at_end);
565 /* If this block ends in a jump insn, add any uses or even clobbers
566 of branch target registers that it might have. */
567 for (insn = BB_END (bb); insn != BB_HEAD (bb) && ! INSN_P (insn); )
568 insn = PREV_INSN (insn);
569 /* ??? for the fall-through edge, it would make sense to insert the
570 btr set on the edge, but that would require to split the block
571 early on so that we can distinguish between dominance from the fall
572 through edge - which can use the call-clobbered registers - from
573 dominance by the throw edge. */
574 if (can_throw_internal (insn))
575 {
576 HARD_REG_SET tmp;
577
578 COPY_HARD_REG_SET (tmp, call_used_reg_set);
579 AND_HARD_REG_SET (tmp, all_btrs);
580 IOR_HARD_REG_SET (btrs_live_at_end[i], tmp);
581 can_throw = 1;
582 }
583 if (can_throw || GET_CODE (insn) == JUMP_INSN)
584 {
585 int regno;
586
587 for (regno = first_btr; regno <= last_btr; regno++)
588 if (refers_to_regno_p (regno, regno+1, insn, NULL))
589 SET_HARD_REG_BIT (btrs_live_at_end[i], regno);
590 }
591
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592 if (rtl_dump_file)
593 dump_btrs_live(i);
594 }
595}
596
597static void
598compute_kill (sbitmap *bb_kill, sbitmap *btr_defset,
599 HARD_REG_SET *btrs_written)
600{
601 int i;
602 int regno;
603
604 /* For each basic block, form the set BB_KILL - the set
71c0e7fc 605 of definitions that the block kills. */
fe3ad572
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606 sbitmap_vector_zero (bb_kill, n_basic_blocks);
607 for (i = 0; i < n_basic_blocks; i++)
608 {
609 for (regno = first_btr; regno <= last_btr; regno++)
610 if (TEST_HARD_REG_BIT (all_btrs, regno)
611 && TEST_HARD_REG_BIT (btrs_written[i], regno))
612 sbitmap_a_or_b (bb_kill[i], bb_kill[i],
613 btr_defset[regno - first_btr]);
614 }
615}
616
617static void
618compute_out (sbitmap *bb_out, sbitmap *bb_gen, sbitmap *bb_kill, int max_uid)
619{
620 /* Perform iterative dataflow:
621 Initially, for all blocks, BB_OUT = BB_GEN.
622 For each block,
623 BB_IN = union over predecessors of BB_OUT(pred)
624 BB_OUT = (BB_IN - BB_KILL) + BB_GEN
f9da5064 625 Iterate until the bb_out sets stop growing. */
fe3ad572
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626 int i;
627 int changed;
628 sbitmap bb_in = sbitmap_alloc (max_uid);
629
630 for (i = 0; i < n_basic_blocks; i++)
631 sbitmap_copy (bb_out[i], bb_gen[i]);
632
633 changed = 1;
634 while (changed)
635 {
636 changed = 0;
637 for (i = 0; i < n_basic_blocks; i++)
638 {
639 sbitmap_union_of_preds (bb_in, bb_out, i);
640 changed |= sbitmap_union_of_diff_cg (bb_out[i], bb_gen[i],
641 bb_in, bb_kill[i]);
642 }
643 }
644 sbitmap_free (bb_in);
645}
646
647static void
648link_btr_uses (btr_def *def_array, btr_user *use_array, sbitmap *bb_out,
649 sbitmap *btr_defset, int max_uid)
650{
651 int i;
652 sbitmap reaching_defs = sbitmap_alloc (max_uid);
653
654 /* Link uses to the uses lists of all of their reaching defs.
71c0e7fc 655 Count up the number of reaching defs of each use. */
fe3ad572
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656 for (i = 0; i < n_basic_blocks; i++)
657 {
658 basic_block bb = BASIC_BLOCK (i);
659 rtx insn;
660 rtx last;
661
662 sbitmap_union_of_preds (reaching_defs, bb_out, i);
a813c111 663 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb));
fe3ad572
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664 insn != last;
665 insn = NEXT_INSN (insn))
666 {
667 if (INSN_P (insn))
668 {
669 int insn_uid = INSN_UID (insn);
670
671 btr_def def = def_array[insn_uid];
672 btr_user user = use_array[insn_uid];
673 if (def != NULL)
674 {
675 /* Remove all reaching defs of regno except
71c0e7fc 676 for this one. */
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677 sbitmap_difference (reaching_defs, reaching_defs,
678 btr_defset[def->btr - first_btr]);
679 SET_BIT(reaching_defs, insn_uid);
680 }
681
682 if (user != NULL)
683 {
f9da5064 684 /* Find all the reaching defs for this use. */
fe3ad572
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685 sbitmap reaching_defs_of_reg = sbitmap_alloc(max_uid);
686 int uid;
687
688 if (user->use)
689 sbitmap_a_and_b (
690 reaching_defs_of_reg,
691 reaching_defs,
692 btr_defset[REGNO (user->use) - first_btr]);
693 else
694 {
695 int reg;
696
697 sbitmap_zero (reaching_defs_of_reg);
698 for (reg = first_btr; reg <= last_btr; reg++)
699 if (TEST_HARD_REG_BIT (all_btrs, reg)
700 && refers_to_regno_p (reg, reg + 1, user->insn,
701 NULL))
702 sbitmap_a_or_b_and_c (reaching_defs_of_reg,
703 reaching_defs_of_reg,
704 reaching_defs,
705 btr_defset[reg - first_btr]);
706 }
707 EXECUTE_IF_SET_IN_SBITMAP (reaching_defs_of_reg, 0, uid,
708 {
709 btr_def def = def_array[uid];
710
f9da5064 711 /* We now know that def reaches user. */
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712
713 if (rtl_dump_file)
714 fprintf (rtl_dump_file,
715 "Def in insn %d reaches use in insn %d\n",
716 uid, insn_uid);
717
718 user->n_reaching_defs++;
719 if (!user->use)
720 def->has_ambiguous_use = 1;
721 if (user->first_reaching_def != -1)
722 { /* There is more than one reaching def. This is
723 a rare case, so just give up on this def/use
71c0e7fc 724 web when it occurs. */
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725 def->has_ambiguous_use = 1;
726 def_array[user->first_reaching_def]
727 ->has_ambiguous_use = 1;
728 if (rtl_dump_file)
729 fprintf (rtl_dump_file,
730 "(use %d has multiple reaching defs)\n",
731 insn_uid);
732 }
733 else
734 user->first_reaching_def = uid;
735 if (user->other_use_this_block)
736 def->other_btr_uses_after_use = 1;
737 user->next = def->uses;
738 def->uses = user;
739 });
740 sbitmap_free (reaching_defs_of_reg);
741 }
742
743 if (GET_CODE (insn) == CALL_INSN)
744 {
745 int regno;
746
747 for (regno = first_btr; regno <= last_btr; regno++)
748 if (TEST_HARD_REG_BIT (all_btrs, regno)
749 && TEST_HARD_REG_BIT (call_used_reg_set, regno))
750 sbitmap_difference (reaching_defs, reaching_defs,
751 btr_defset[regno - first_btr]);
752 }
753 }
754 }
755 }
756 sbitmap_free (reaching_defs);
757}
758
759static void
760build_btr_def_use_webs (fibheap_t all_btr_defs)
761{
762 const int max_uid = get_max_uid ();
763 btr_def *def_array = xcalloc (max_uid, sizeof (btr_def));
764 btr_user *use_array = xcalloc (max_uid, sizeof (btr_user));
765 sbitmap *btr_defset = sbitmap_vector_alloc (
766 (last_btr - first_btr) + 1, max_uid);
767 sbitmap *bb_gen = sbitmap_vector_alloc (n_basic_blocks, max_uid);
703ad42b 768 HARD_REG_SET *btrs_written = xcalloc (n_basic_blocks, sizeof (HARD_REG_SET));
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769 sbitmap *bb_kill;
770 sbitmap *bb_out;
771
772 sbitmap_vector_zero (btr_defset, (last_btr - first_btr) + 1);
773
774 compute_defs_uses_and_gen (all_btr_defs, def_array, use_array, btr_defset,
775 bb_gen, btrs_written);
776
777 bb_kill = sbitmap_vector_alloc (n_basic_blocks, max_uid);
778 compute_kill (bb_kill, btr_defset, btrs_written);
779 free (btrs_written);
780
781 bb_out = sbitmap_vector_alloc (n_basic_blocks, max_uid);
782 compute_out (bb_out, bb_gen, bb_kill, max_uid);
783
784 sbitmap_vector_free (bb_gen);
785 sbitmap_vector_free (bb_kill);
786
787 link_btr_uses (def_array, use_array, bb_out, btr_defset, max_uid);
788
789 sbitmap_vector_free (bb_out);
790 sbitmap_vector_free (btr_defset);
791 free (use_array);
792 free (def_array);
793}
794
795/* Return true if basic block BB contains the start or end of the
796 live range of the definition DEF, AND there are other live
797 ranges of the same target register that include BB. */
798static int
799block_at_edge_of_live_range_p (int bb, btr_def def)
800{
801 if (def->other_btr_uses_before_def && BASIC_BLOCK (bb) == def->bb)
802 return 1;
803 else if (def->other_btr_uses_after_use)
804 {
805 btr_user user;
806 for (user = def->uses; user != NULL; user = user->next)
807 if (BASIC_BLOCK (bb) == user->bb)
808 return 1;
809 }
810 return 0;
811}
812
813/* We are removing the def/use web DEF. The target register
814 used in this web is therefore no longer live in the live range
815 of this web, so remove it from the live set of all basic blocks
816 in the live range of the web.
817 Blocks at the boundary of the live range may contain other live
818 ranges for the same target register, so we have to be careful
819 to remove the target register from the live set of these blocks
71c0e7fc 820 only if they do not contain other live ranges for the same register. */
fe3ad572
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821static void
822clear_btr_from_live_range (btr_def def)
823{
824 int bb;
825
826 EXECUTE_IF_SET_IN_BITMAP
827 (def->live_range, 0, bb,
828 {
829 if ((!def->other_btr_uses_before_def
830 && !def->other_btr_uses_after_use)
831 || !block_at_edge_of_live_range_p (bb, def))
832 {
833 CLEAR_HARD_REG_BIT (btrs_live[bb], def->btr);
1194fc79 834 CLEAR_HARD_REG_BIT (btrs_live_at_end[bb], def->btr);
fe3ad572
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835 if (rtl_dump_file)
836 dump_btrs_live (bb);
837 }
838 });
839}
840
841
842/* We are adding the def/use web DEF. Add the target register used
843 in this web to the live set of all of the basic blocks that contain
844 the live range of the web. */
845static void
846add_btr_to_live_range (btr_def def)
847{
848 int bb;
849 EXECUTE_IF_SET_IN_BITMAP
850 (def->live_range, 0, bb,
851 {
852 SET_HARD_REG_BIT (btrs_live[bb], def->btr);
1194fc79 853 SET_HARD_REG_BIT (btrs_live_at_end[bb], def->btr);
fe3ad572
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854 if (rtl_dump_file)
855 dump_btrs_live (bb);
856 });
857}
858
859/* Update a live range to contain the basic block NEW_BLOCK, and all
860 blocks on paths between the existing live range and NEW_BLOCK.
861 HEAD is a block contained in the existing live range that dominates
862 all other blocks in the existing live range.
863 Also add to the set BTRS_LIVE_IN_RANGE all target registers that
864 are live in the blocks that we add to the live range.
865 It is a precondition that either NEW_BLOCK dominates HEAD,or
866 HEAD dom NEW_BLOCK. This is used to speed up the
867 implementation of this function. */
868static void
869augment_live_range (bitmap live_range, HARD_REG_SET *btrs_live_in_range,
870 basic_block head_bb, basic_block new_bb)
871{
872 basic_block *worklist, *tos;
873
703ad42b 874 tos = worklist = xmalloc (sizeof (basic_block) * (n_basic_blocks + 1));
fe3ad572 875
d47cc544 876 if (dominated_by_p (CDI_DOMINATORS, new_bb, head_bb))
fe3ad572 877 *tos++ = new_bb;
d47cc544 878 else if (dominated_by_p (CDI_DOMINATORS, head_bb, new_bb))
fe3ad572
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879 {
880 edge e;
881 int new_block = new_bb->index;
882
883 bitmap_set_bit (live_range, new_block);
1194fc79
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884 if (flag_btr_bb_exclusive)
885 IOR_HARD_REG_SET (*btrs_live_in_range, btrs_live[new_block]);
886 else
887 {
888 IOR_HARD_REG_SET (*btrs_live_in_range, btrs_live_at_end[new_block]);
889 IOR_HARD_REG_SET (*btrs_live_in_range, btrs_live[head_bb->index]);
890 }
fe3ad572
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891 if (rtl_dump_file)
892 {
893 fprintf (rtl_dump_file,
1194fc79
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894 "Adding end of block %d and rest of %d to live range\n",
895 new_block, head_bb->index);
fe3ad572
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896 fprintf (rtl_dump_file,"Now live btrs are ");
897 dump_hard_reg_set (*btrs_live_in_range);
898 fprintf (rtl_dump_file, "\n");
899 }
900 for (e = head_bb->pred; e; e = e->pred_next)
901 *tos++ = e->src;
902 }
903 else
904 abort();
905
906 while (tos != worklist)
907 {
908 basic_block bb = *--tos;
909 if (!bitmap_bit_p (live_range, bb->index))
910 {
911 edge e;
912
913 bitmap_set_bit (live_range, bb->index);
914 IOR_HARD_REG_SET (*btrs_live_in_range,
915 btrs_live[bb->index]);
916 if (rtl_dump_file)
917 {
918 fprintf (rtl_dump_file,
919 "Adding block %d to live range\n", bb->index);
920 fprintf (rtl_dump_file,"Now live btrs are ");
921 dump_hard_reg_set (*btrs_live_in_range);
922 fprintf (rtl_dump_file, "\n");
923 }
924
925 for (e = bb->pred; e != NULL; e = e->pred_next)
926 {
927 basic_block pred = e->src;
928 if (!bitmap_bit_p (live_range, pred->index))
929 *tos++ = pred;
930 }
931 }
932 }
933
934 free (worklist);
935}
936
937/* Return the most desirable target register that is not in
938 the set USED_BTRS. */
939static int
940choose_btr (HARD_REG_SET used_btrs)
941{
942 int i;
943 GO_IF_HARD_REG_SUBSET (all_btrs, used_btrs, give_up);
944
945 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
946 {
947#ifdef REG_ALLOC_ORDER
948 int regno = reg_alloc_order[i];
949#else
950 int regno = i;
951#endif
952 if (TEST_HARD_REG_BIT (all_btrs, regno)
953 && !TEST_HARD_REG_BIT (used_btrs, regno))
954 return regno;
955 }
956give_up:
957 return -1;
958}
959
960/* Calculate the set of basic blocks that contain the live range of
961 the def/use web DEF.
962 Also calculate the set of target registers that are live at time
963 in this live range, but ignore the live range represented by DEF
964 when calculating this set. */
965static void
966btr_def_live_range (btr_def def, HARD_REG_SET *btrs_live_in_range)
967{
968 if (!def->live_range)
969 {
970 btr_user user;
971
972 def->live_range = BITMAP_XMALLOC ();
973
974 bitmap_set_bit (def->live_range, def->bb->index);
1194fc79
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975 if (flag_btr_bb_exclusive)
976 COPY_HARD_REG_SET (*btrs_live_in_range, btrs_live[def->bb->index]);
977 else
978 COPY_HARD_REG_SET (*btrs_live_in_range,
979 btrs_live_at_end[def->bb->index]);
fe3ad572
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980
981 for (user = def->uses; user != NULL; user = user->next)
982 augment_live_range (def->live_range, btrs_live_in_range,
983 def->bb, user->bb);
984 }
985 else
986 {
987 /* def->live_range is accurate, but we need to recompute
988 the set of target registers live over it, because migration
989 of other PT instructions may have affected it.
990 */
991 int bb;
1194fc79 992 int def_bb = def->bb->index;
fe3ad572
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993
994 CLEAR_HARD_REG_SET (*btrs_live_in_range);
1194fc79
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995 if (flag_btr_bb_exclusive)
996 EXECUTE_IF_SET_IN_BITMAP
997 (def->live_range, 0, bb,
998 {
999 IOR_HARD_REG_SET (*btrs_live_in_range, btrs_live[bb]);
1000 });
1001 else
1002 EXECUTE_IF_SET_IN_BITMAP
1003 (def->live_range, 0, bb,
1004 {
1005 IOR_HARD_REG_SET (*btrs_live_in_range,
1006 (def_bb == bb
1007 ? btrs_live_at_end : btrs_live) [bb]);
1008 });
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1009 }
1010 if (!def->other_btr_uses_before_def &&
1011 !def->other_btr_uses_after_use)
1012 CLEAR_HARD_REG_BIT (*btrs_live_in_range, def->btr);
1013}
1014
1015/* Merge into the def/use web DEF any other def/use webs in the same
1016 group that are dominated by DEF, provided that there is a target
1017 register available to allocate to the merged web. */
1018static void
1019combine_btr_defs (btr_def def, HARD_REG_SET *btrs_live_in_range)
1020{
1021 btr_def other_def;
1022
1023 for (other_def = def->group->members;
1024 other_def != NULL;
1025 other_def = other_def->next_this_group)
1026 {
1027 if (other_def != def
1028 && other_def->uses != NULL
1029 && ! other_def->has_ambiguous_use
d47cc544 1030 && dominated_by_p (CDI_DOMINATORS, other_def->bb, def->bb))
fe3ad572
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1031 {
1032 /* def->bb dominates the other def, so def and other_def could
71c0e7fc 1033 be combined. */
fe3ad572 1034 /* Merge their live ranges, and get the set of
71c0e7fc 1035 target registers live over the merged range. */
fe3ad572
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1036 int btr;
1037 HARD_REG_SET combined_btrs_live;
1038 bitmap combined_live_range = BITMAP_XMALLOC ();
1039 btr_user user;
1040
1041 if (other_def->live_range == NULL)
1042 {
1043 HARD_REG_SET dummy_btrs_live_in_range;
1044 btr_def_live_range (other_def, &dummy_btrs_live_in_range);
1045 }
1046 COPY_HARD_REG_SET (combined_btrs_live, *btrs_live_in_range);
1047 bitmap_copy (combined_live_range, def->live_range);
1048
1049 for (user = other_def->uses; user != NULL; user = user->next)
1050 augment_live_range (combined_live_range, &combined_btrs_live,
1051 def->bb, user->bb);
1052
1053 btr = choose_btr (combined_btrs_live);
1054 if (btr != -1)
1055 {
f9da5064 1056 /* We can combine them. */
fe3ad572
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1057 if (rtl_dump_file)
1058 fprintf (rtl_dump_file,
1059 "Combining def in insn %d with def in insn %d\n",
1060 INSN_UID (other_def->insn), INSN_UID (def->insn));
1061
1062 def->btr = btr;
1063 user = other_def->uses;
1064 while (user != NULL)
1065 {
1066 btr_user next = user->next;
1067
1068 user->next = def->uses;
1069 def->uses = user;
1070 user = next;
1071 }
1072 /* Combining def/use webs can make target registers live
1073 after uses where they previously were not. This means
1074 some REG_DEAD notes may no longer be correct. We could
1075 be more precise about this if we looked at the combined
1076 live range, but here I just delete any REG_DEAD notes
71c0e7fc 1077 in case they are no longer correct. */
fe3ad572
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1078 for (user = def->uses; user != NULL; user = user->next)
1079 remove_note (user->insn,
1080 find_regno_note (user->insn, REG_DEAD,
1081 REGNO (user->use)));
1082 clear_btr_from_live_range (other_def);
1083 other_def->uses = NULL;
1084 bitmap_copy (def->live_range, combined_live_range);
1085 if (other_def->other_btr_uses_after_use)
1086 def->other_btr_uses_after_use = 1;
1087 COPY_HARD_REG_SET (*btrs_live_in_range, combined_btrs_live);
1088
f9da5064 1089 /* Delete the old target register initialization. */
fe3ad572
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1090 delete_insn (other_def->insn);
1091
1092 }
1093 BITMAP_XFREE (combined_live_range);
1094 }
1095 }
1096}
1097
1098/* Move the definition DEF from its current position to basic
1099 block NEW_DEF_BB, and modify it to use branch target register BTR.
1100 Delete the old defining insn, and insert a new one in NEW_DEF_BB.
1101 Update all reaching uses of DEF in the RTL to use BTR.
1102 If this new position means that other defs in the
1103 same group can be combined with DEF then combine them. */
1104static void
1105move_btr_def (basic_block new_def_bb, int btr, btr_def def, bitmap live_range,
1106 HARD_REG_SET *btrs_live_in_range)
1107{
1108 /* We can move the instruction.
1109 Set a target register in block NEW_DEF_BB to the value
1110 needed for this target register definition.
1111 Replace all uses of the old target register definition by
71c0e7fc 1112 uses of the new definition. Delete the old definition. */
fe3ad572 1113 basic_block b = new_def_bb;
a813c111 1114 rtx insp = BB_HEAD (b);
fe3ad572
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1115 rtx old_insn = def->insn;
1116 rtx src;
1117 rtx btr_rtx;
1118 rtx new_insn;
1119 enum machine_mode btr_mode;
1120 btr_user user;
1121 rtx set;
1122
1123 if (rtl_dump_file)
1124 fprintf(rtl_dump_file, "migrating to basic block %d, using reg %d\n",
1125 new_def_bb->index, btr);
1126
1127 clear_btr_from_live_range (def);
1128 def->btr = btr;
1129 def->bb = new_def_bb;
1130 def->luid = 0;
1131 def->cost = basic_block_freq (new_def_bb);
1194fc79
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1132 def->other_btr_uses_before_def
1133 = TEST_HARD_REG_BIT (btrs_live[b->index], btr) ? 1 : 0;
fe3ad572
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1134 bitmap_copy (def->live_range, live_range);
1135 combine_btr_defs (def, btrs_live_in_range);
1136 btr = def->btr;
1137 add_btr_to_live_range (def);
1138 if (GET_CODE (insp) == CODE_LABEL)
1139 insp = NEXT_INSN (insp);
1140 /* N.B.: insp is expected to be NOTE_INSN_BASIC_BLOCK now. Some
1141 optimizations can result in insp being both first and last insn of
1142 its basic block. */
1143 /* ?? some assertions to check that insp is sensible? */
1144
1194fc79
R
1145 if (def->other_btr_uses_before_def)
1146 {
1147 insp = BB_END (b);
1148 for (insp = BB_END (b); ! INSN_P (insp); insp = PREV_INSN (insp))
1149 if (insp == BB_HEAD (b))
1150 abort ();
1151 if (GET_CODE (insp) == JUMP_INSN || can_throw_internal (insp))
1152 insp = PREV_INSN (insp);
1153 }
1154
fe3ad572
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1155 set = single_set (old_insn);
1156 src = SET_SRC (set);
1157 btr_mode = GET_MODE (SET_DEST (set));
f84d109f 1158 btr_rtx = gen_rtx_REG (btr_mode, btr);
fe3ad572
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1159
1160 new_insn = gen_move_insn (btr_rtx, src);
1161
71c0e7fc 1162 /* Insert target register initialization at head of basic block. */
fe3ad572
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1163 def->insn = emit_insn_after (new_insn, insp);
1164
1165 regs_ever_live[btr] = 1;
1166
1167 if (rtl_dump_file)
1168 fprintf (rtl_dump_file, "New pt is insn %d, inserted after insn %d\n",
1169 INSN_UID (def->insn), INSN_UID (insp));
1170
f9da5064 1171 /* Delete the old target register initialization. */
fe3ad572
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1172 delete_insn (old_insn);
1173
1174 /* Replace each use of the old target register by a use of the new target
71c0e7fc 1175 register. */
fe3ad572
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1176 for (user = def->uses; user != NULL; user = user->next)
1177 {
1178 /* Some extra work here to ensure consistent modes, because
1179 it seems that a target register REG rtx can be given a different
1180 mode depending on the context (surely that should not be
71c0e7fc 1181 the case?). */
fe3ad572
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1182 rtx replacement_rtx;
1183 if (GET_MODE (user->use) == GET_MODE (btr_rtx)
1184 || GET_MODE (user->use) == VOIDmode)
1185 replacement_rtx = btr_rtx;
1186 else
f84d109f 1187 replacement_rtx = gen_rtx_REG (GET_MODE (user->use), btr);
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1188 replace_rtx (user->insn, user->use, replacement_rtx);
1189 user->use = replacement_rtx;
1190 }
1191}
1192
1193/* We anticipate intra-block scheduling to be done. See if INSN could move
1194 up within BB by N_INSNS. */
1195static int
1196can_move_up (basic_block bb, rtx insn, int n_insns)
1197{
a813c111 1198 while (insn != BB_HEAD (bb) && n_insns > 0)
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1199 {
1200 insn = PREV_INSN (insn);
1201 /* ??? What if we have an anti-dependency that actually prevents the
1202 scheduler from doing the move? We'd like to re-allocate the register,
1203 but not necessarily put the load into another basic block. */
1204 if (INSN_P (insn))
1205 n_insns--;
1206 }
1207 return n_insns <= 0;
1208}
1209
1210/* Attempt to migrate the target register definition DEF to an
1211 earlier point in the flowgraph.
1212
1213 It is a precondition of this function that DEF is migratable:
1214 i.e. it has a constant source, and all uses are unambiguous.
1215
1216 Only migrations that reduce the cost of DEF will be made.
1217 MIN_COST is the lower bound on the cost of the DEF after migration.
1218 If we migrate DEF so that its cost falls below MIN_COST,
1219 then we do not attempt to migrate further. The idea is that
4d6922ee 1220 we migrate definitions in a priority order based on their cost,
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1221 when the cost of this definition falls below MIN_COST, then
1222 there is another definition with cost == MIN_COST which now
1223 has a higher priority than this definition.
1224
cc0efd0b 1225 Return nonzero if there may be benefit from attempting to
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1226 migrate this DEF further (i.e. we have reduced the cost below
1227 MIN_COST, but we may be able to reduce it further).
71c0e7fc 1228 Return zero if no further migration is possible. */
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1229static int
1230migrate_btr_def (btr_def def, int min_cost)
1231{
1232 bitmap live_range;
1233 HARD_REG_SET btrs_live_in_range;
1234 int btr_used_near_def = 0;
1235 int def_basic_block_freq;
1236 basic_block try;
1237 int give_up = 0;
1238 int def_moved = 0;
1239 btr_user user;
5a9384dd 1240 int def_latency = 1;
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1241
1242 if (rtl_dump_file)
1243 fprintf (rtl_dump_file,
1244 "Attempting to migrate pt from insn %d (cost = %d, min_cost = %d) ... ",
1245 INSN_UID (def->insn), def->cost, min_cost);
1246
1247 if (!def->group || def->has_ambiguous_use)
f9da5064 1248 /* These defs are not migratable. */
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1249 {
1250 if (rtl_dump_file)
1251 fprintf (rtl_dump_file, "it's not migratable\n");
1252 return 0;
1253 }
1254
1255 if (!def->uses)
1256 /* We have combined this def with another in the same group, so
1257 no need to consider it further.
1258 */
1259 {
1260 if (rtl_dump_file)
1261 fprintf (rtl_dump_file, "it's already combined with another pt\n");
1262 return 0;
1263 }
1264
1265 btr_def_live_range (def, &btrs_live_in_range);
1266 live_range = BITMAP_XMALLOC ();
1267 bitmap_copy (live_range, def->live_range);
1268
5a9384dd 1269#ifdef INSN_SCHEDULING
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1270 if ((*targetm.sched.use_dfa_pipeline_interface) ())
1271 def_latency = insn_default_latency (def->insn);
1272 else
1273 def_latency = result_ready_cost (def->insn);
5a9384dd
HPN
1274#endif
1275
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1276 def_latency *= issue_rate;
1277
1278 for (user = def->uses; user != NULL; user = user->next)
1279 {
1280 if (user->bb == def->bb
1281 && user->luid > def->luid
1282 && (def->luid + def_latency) > user->luid
1283 && ! can_move_up (def->bb, def->insn,
1284 (def->luid + def_latency) - user->luid))
1285 {
1286 btr_used_near_def = 1;
1287 break;
1288 }
1289 }
1290
1291 def_basic_block_freq = basic_block_freq (def->bb);
1292
d47cc544 1293 for (try = get_immediate_dominator (CDI_DOMINATORS, def->bb);
fe3ad572 1294 !give_up && try && try != ENTRY_BLOCK_PTR && def->cost >= min_cost;
d47cc544 1295 try = get_immediate_dominator (CDI_DOMINATORS, try))
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1296 {
1297 /* Try to move the instruction that sets the target register into
71c0e7fc 1298 basic block TRY. */
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1299 int try_freq = basic_block_freq (try);
1300
1301 if (rtl_dump_file)
1302 fprintf (rtl_dump_file, "trying block %d ...", try->index);
1303
1304 if (try_freq < def_basic_block_freq
1305 || (try_freq == def_basic_block_freq && btr_used_near_def))
1306 {
1307 int btr;
1308 augment_live_range (live_range, &btrs_live_in_range, def->bb, try);
1309 if (rtl_dump_file)
1310 {
1311 fprintf (rtl_dump_file, "Now btrs live in range are: ");
1312 dump_hard_reg_set (btrs_live_in_range);
1313 fprintf (rtl_dump_file, "\n");
1314 }
1315 btr = choose_btr (btrs_live_in_range);
1316 if (btr != -1)
1317 {
1318 move_btr_def (try, btr, def, live_range, &btrs_live_in_range);
1319 bitmap_copy(live_range, def->live_range);
1320 btr_used_near_def = 0;
1321 def_moved = 1;
1322 def_basic_block_freq = basic_block_freq (def->bb);
1323 }
1324 else
1325 {
1326 /* There are no free target registers available to move
1327 this far forward, so give up */
1328 give_up = 1;
1329 if (rtl_dump_file)
1330 fprintf (rtl_dump_file,
1331 "giving up because there are no free target registers\n");
1332 }
1333
1334 }
1335 }
1336 if (!def_moved)
1337 {
1338 give_up = 1;
1339 if (rtl_dump_file)
1340 fprintf (rtl_dump_file, "failed to move\n");
1341 }
1342 BITMAP_XFREE (live_range);
1343 return !give_up;
1344}
1345
1346/* Attempt to move instructions that set target registers earlier
71c0e7fc 1347 in the flowgraph, away from their corresponding uses. */
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1348static void
1349migrate_btr_defs (enum reg_class btr_class, int allow_callee_save)
1350{
1351 fibheap_t all_btr_defs = fibheap_new ();
1352 int reg;
1353
1354 gcc_obstack_init (&migrate_btrl_obstack);
1355 if (rtl_dump_file)
1356 {
1357 int i;
1358
1359 for (i = 0; i < n_basic_blocks; i++)
1360 {
1361 basic_block bb = BASIC_BLOCK (i);
1362 fprintf(rtl_dump_file,
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1363 "Basic block %d: count = " HOST_WIDEST_INT_PRINT_DEC
1364 " loop-depth = %d idom = %d\n",
1365 i, (HOST_WIDEST_INT) bb->count, bb->loop_depth,
d47cc544 1366 get_immediate_dominator (CDI_DOMINATORS, bb)->index);
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1367 }
1368 }
1369
1370 CLEAR_HARD_REG_SET (all_btrs);
1371 for (first_btr = -1, reg = 0; reg < FIRST_PSEUDO_REGISTER; reg++)
1372 if (TEST_HARD_REG_BIT (reg_class_contents[(int) btr_class], reg)
1373 && (allow_callee_save || call_used_regs[reg] || regs_ever_live[reg]))
1374 {
1375 SET_HARD_REG_BIT (all_btrs, reg);
1376 last_btr = reg;
1377 if (first_btr < 0)
1378 first_btr = reg;
1379 }
1380
703ad42b 1381 btrs_live = xcalloc (n_basic_blocks, sizeof (HARD_REG_SET));
1194fc79 1382 btrs_live_at_end = xcalloc (n_basic_blocks, sizeof (HARD_REG_SET));
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1383
1384 build_btr_def_use_webs (all_btr_defs);
1385
1386 while (!fibheap_empty (all_btr_defs))
1387 {
1388 btr_def def =
1389 (btr_def) fibheap_extract_min (all_btr_defs);
1390 int min_cost = -fibheap_min_key (all_btr_defs);
1391 if (migrate_btr_def (def, min_cost))
1392 {
1393 fibheap_insert (all_btr_defs, -def->cost, (void *) def);
1394 if (rtl_dump_file)
1395 {
1396 fprintf (rtl_dump_file,
1397 "Putting insn %d back on queue with priority %d\n",
1398 INSN_UID (def->insn), def->cost);
1399 }
1400 }
1401 else
1402 {
1403 if (def->live_range)
1404 BITMAP_XFREE (def->live_range);
1405 }
1406 }
1407
1408 free (btrs_live);
1194fc79 1409 free (btrs_live_at_end);
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1410 obstack_free (&migrate_btrl_obstack, NULL);
1411 fibheap_delete (all_btr_defs);
1412}
1413
1414void
1415branch_target_load_optimize (rtx insns, bool after_prologue_epilogue_gen)
1416{
1417 enum reg_class class = (*targetm.branch_target_register_class) ();
1418 if (class != NO_REGS)
1419 {
1420 /* Initialize issue_rate. */
1421 if (targetm.sched.issue_rate)
1422 issue_rate = (*targetm.sched.issue_rate) ();
1423 else
1424 issue_rate = 1;
1425
71c0e7fc 1426 /* Build the CFG for migrate_btr_defs. */
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1427#if 1
1428 /* This may or may not be needed, depending on where we
71c0e7fc 1429 run this phase. */
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1430 cleanup_cfg (optimize ? CLEANUP_EXPENSIVE : 0);
1431#endif
1432
1433 life_analysis (insns, NULL, 0);
1434
71c0e7fc 1435 /* Dominator info is also needed for migrate_btr_def. */
d47cc544 1436 calculate_dominance_info (CDI_DOMINATORS);
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1437 migrate_btr_defs (class,
1438 ((*targetm.branch_target_register_callee_saved)
1439 (after_prologue_epilogue_gen)));
1440
d47cc544 1441 free_dominance_info (CDI_DOMINATORS);
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1442
1443 update_life_info (NULL, UPDATE_LIFE_GLOBAL_RM_NOTES,
1444 PROP_DEATH_NOTES | PROP_REG_INFO);
1445 }
1446}
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