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38398762 RK |
1 | /* Allocate registers for pseudo-registers that span basic blocks. |
2 | Copyright (C) 1987-1991 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GNU CC. | |
5 | ||
6 | GNU CC is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GNU CC is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GNU CC; see the file COPYING. If not, write to | |
18 | the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
19 | ||
20 | ||
21 | #include <stdio.h> | |
22 | #include "config.h" | |
23 | #include "rtl.h" | |
24 | #include "flags.h" | |
25 | #include "basic-block.h" | |
26 | #include "hard-reg-set.h" | |
27 | #include "regs.h" | |
28 | #include "insn-config.h" | |
29 | #include "output.h" | |
30 | ||
31 | /* This pass of the compiler performs global register allocation. | |
32 | It assigns hard register numbers to all the pseudo registers | |
33 | that were not handled in local_alloc. Assignments are recorded | |
34 | in the vector reg_renumber, not by changing the rtl code. | |
35 | (Such changes are made by final). The entry point is | |
36 | the function global_alloc. | |
37 | ||
38 | After allocation is complete, the reload pass is run as a subroutine | |
39 | of this pass, so that when a pseudo reg loses its hard reg due to | |
40 | spilling it is possible to make a second attempt to find a hard | |
41 | reg for it. The reload pass is independent in other respects | |
42 | and it is run even when stupid register allocation is in use. | |
43 | ||
44 | 1. count the pseudo-registers still needing allocation | |
45 | and assign allocation-numbers (allocnos) to them. | |
46 | Set up tables reg_allocno and allocno_reg to map | |
47 | reg numbers to allocnos and vice versa. | |
48 | max_allocno gets the number of allocnos in use. | |
49 | ||
50 | 2. Allocate a max_allocno by max_allocno conflict bit matrix and clear it. | |
51 | Allocate a max_allocno by FIRST_PSEUDO_REGISTER conflict matrix | |
52 | for conflicts between allocnos and explicit hard register use | |
53 | (which includes use of pseudo-registers allocated by local_alloc). | |
54 | ||
55 | 3. for each basic block | |
56 | walk forward through the block, recording which | |
57 | unallocated registers and which hardware registers are live. | |
58 | Build the conflict matrix between the unallocated registers | |
59 | and another of unallocated registers versus hardware registers. | |
60 | Also record the preferred hardware registers | |
61 | for each unallocated one. | |
62 | ||
63 | 4. Sort a table of the allocnos into order of | |
64 | desirability of the variables. | |
65 | ||
66 | 5. Allocate the variables in that order; each if possible into | |
67 | a preferred register, else into another register. */ | |
68 | \f | |
69 | /* Number of pseudo-registers still requiring allocation | |
70 | (not allocated by local_allocate). */ | |
71 | ||
72 | static int max_allocno; | |
73 | ||
74 | /* Indexed by (pseudo) reg number, gives the allocno, or -1 | |
75 | for pseudo registers already allocated by local_allocate. */ | |
76 | ||
77 | static int *reg_allocno; | |
78 | ||
79 | /* Indexed by allocno, gives the reg number. */ | |
80 | ||
81 | static int *allocno_reg; | |
82 | ||
83 | /* A vector of the integers from 0 to max_allocno-1, | |
84 | sorted in the order of first-to-be-allocated first. */ | |
85 | ||
86 | static int *allocno_order; | |
87 | ||
88 | /* Indexed by an allocno, gives the number of consecutive | |
89 | hard registers needed by that pseudo reg. */ | |
90 | ||
91 | static int *allocno_size; | |
92 | ||
93 | /* Indexed by (pseudo) reg number, gives the number of another | |
94 | lower-numbered pseudo reg which can share a hard reg with this peudo | |
95 | *even if the two pseudos would otherwise appear to conflict*. */ | |
96 | ||
97 | static int *reg_may_share; | |
98 | ||
99 | /* max_allocno by max_allocno array of bits, | |
100 | recording whether two allocno's conflict (can't go in the same | |
101 | hardware register). | |
102 | ||
103 | `conflicts' is not symmetric; a conflict between allocno's i and j | |
104 | is recorded either in element i,j or in element j,i. */ | |
105 | ||
106 | static int *conflicts; | |
107 | ||
108 | /* Number of ints require to hold max_allocno bits. | |
109 | This is the length of a row in `conflicts'. */ | |
110 | ||
111 | static int allocno_row_words; | |
112 | ||
113 | /* Two macros to test or store 1 in an element of `conflicts'. */ | |
114 | ||
115 | #define CONFLICTP(I, J) \ | |
116 | (conflicts[(I) * allocno_row_words + (J) / INT_BITS] \ | |
117 | & (1 << ((J) % INT_BITS))) | |
118 | ||
119 | #define SET_CONFLICT(I, J) \ | |
120 | (conflicts[(I) * allocno_row_words + (J) / INT_BITS] \ | |
121 | |= (1 << ((J) % INT_BITS))) | |
122 | ||
123 | /* Set of hard regs currently live (during scan of all insns). */ | |
124 | ||
125 | static HARD_REG_SET hard_regs_live; | |
126 | ||
127 | /* Indexed by N, set of hard regs conflicting with allocno N. */ | |
128 | ||
129 | static HARD_REG_SET *hard_reg_conflicts; | |
130 | ||
131 | /* Indexed by N, set of hard regs preferred by allocno N. | |
132 | This is used to make allocnos go into regs that are copied to or from them, | |
133 | when possible, to reduce register shuffling. */ | |
134 | ||
135 | static HARD_REG_SET *hard_reg_preferences; | |
136 | ||
137 | /* Similar, but just counts register preferences made in simple copy | |
138 | operations, rather than arithmetic. These are given priority because | |
139 | we can always eliminate an insn by using these, but using a register | |
140 | in the above list won't always eliminate an insn. */ | |
141 | ||
142 | static HARD_REG_SET *hard_reg_copy_preferences; | |
143 | ||
144 | /* Similar to hard_reg_preferences, but includes bits for subsequent | |
145 | registers when an allocno is multi-word. The above variable is used for | |
146 | allocation while this is used to build reg_someone_prefers, below. */ | |
147 | ||
148 | static HARD_REG_SET *hard_reg_full_preferences; | |
149 | ||
150 | /* Indexed by N, set of hard registers that some later allocno has a | |
151 | preference for. */ | |
152 | ||
153 | static HARD_REG_SET *regs_someone_prefers; | |
154 | ||
155 | /* Set of registers that global-alloc isn't supposed to use. */ | |
156 | ||
157 | static HARD_REG_SET no_global_alloc_regs; | |
158 | ||
159 | /* Set of registers used so far. */ | |
160 | ||
161 | static HARD_REG_SET regs_used_so_far; | |
162 | ||
163 | /* Number of calls crossed by each allocno. */ | |
164 | ||
165 | static int *allocno_calls_crossed; | |
166 | ||
167 | /* Number of refs (weighted) to each allocno. */ | |
168 | ||
169 | static int *allocno_n_refs; | |
170 | ||
171 | /* Guess at live length of each allocno. | |
172 | This is actually the max of the live lengths of the regs. */ | |
173 | ||
174 | static int *allocno_live_length; | |
175 | ||
1d56e983 RS |
176 | /* Number of refs (weighted) to each hard reg, as used by local alloc. |
177 | It is zero for a reg that contains global pseudos or is explicitly used. */ | |
178 | ||
179 | static int local_reg_n_refs[FIRST_PSEUDO_REGISTER]; | |
180 | ||
181 | /* Guess at live length of each hard reg, as used by local alloc. | |
182 | This is actually the sum of the live lengths of the specific regs. */ | |
183 | ||
184 | static int local_reg_live_length[FIRST_PSEUDO_REGISTER]; | |
185 | ||
38398762 RK |
186 | /* Test a bit in TABLE, a vector of HARD_REG_SETs, |
187 | for vector element I, and hard register number J. */ | |
188 | ||
189 | #define REGBITP(TABLE, I, J) TEST_HARD_REG_BIT (TABLE[I], J) | |
190 | ||
191 | /* Set to 1 a bit in a vector of HARD_REG_SETs. Works like REGBITP. */ | |
192 | ||
193 | #define SET_REGBIT(TABLE, I, J) SET_HARD_REG_BIT (TABLE[I], J) | |
194 | ||
195 | /* Bit mask for allocnos live at current point in the scan. */ | |
196 | ||
197 | static int *allocnos_live; | |
198 | ||
199 | #define INT_BITS HOST_BITS_PER_INT | |
200 | ||
201 | /* Test, set or clear bit number I in allocnos_live, | |
202 | a bit vector indexed by allocno. */ | |
203 | ||
204 | #define ALLOCNO_LIVE_P(I) \ | |
205 | (allocnos_live[(I) / INT_BITS] & (1 << ((I) % INT_BITS))) | |
206 | ||
207 | #define SET_ALLOCNO_LIVE(I) \ | |
208 | (allocnos_live[(I) / INT_BITS] |= (1 << ((I) % INT_BITS))) | |
209 | ||
210 | #define CLEAR_ALLOCNO_LIVE(I) \ | |
211 | (allocnos_live[(I) / INT_BITS] &= ~(1 << ((I) % INT_BITS))) | |
212 | ||
213 | /* This is turned off because it doesn't work right for DImode. | |
214 | (And it is only used for DImode, so the other cases are worthless.) | |
215 | The problem is that it isn't true that there is NO possibility of conflict; | |
216 | only that there is no conflict if the two pseudos get the exact same regs. | |
217 | If they were allocated with a partial overlap, there would be a conflict. | |
218 | We can't safely turn off the conflict unless we have another way to | |
219 | prevent the partial overlap. | |
220 | ||
221 | Idea: change hard_reg_conflicts so that instead of recording which | |
222 | hard regs the allocno may not overlap, it records where the allocno | |
223 | may not start. Change both where it is used and where it is updated. | |
224 | Then there is a way to record that (reg:DI 108) may start at 10 | |
225 | but not at 9 or 11. There is still the question of how to record | |
226 | this semi-conflict between two pseudos. */ | |
227 | #if 0 | |
228 | /* Reg pairs for which conflict after the current insn | |
229 | is inhibited by a REG_NO_CONFLICT note. | |
230 | If the table gets full, we ignore any other notes--that is conservative. */ | |
231 | #define NUM_NO_CONFLICT_PAIRS 4 | |
232 | /* Number of pairs in use in this insn. */ | |
233 | int n_no_conflict_pairs; | |
234 | static struct { int allocno1, allocno2;} | |
235 | no_conflict_pairs[NUM_NO_CONFLICT_PAIRS]; | |
236 | #endif /* 0 */ | |
237 | ||
238 | /* Record all regs that are set in any one insn. | |
239 | Communication from mark_reg_{store,clobber} and global_conflicts. */ | |
240 | ||
241 | static rtx *regs_set; | |
242 | static int n_regs_set; | |
243 | ||
244 | /* All register that can be eliminated. */ | |
245 | ||
246 | static HARD_REG_SET eliminable_regset; | |
247 | ||
248 | static int allocno_compare (); | |
249 | static void mark_reg_store (); | |
250 | static void mark_reg_clobber (); | |
251 | static void mark_reg_live_nc (); | |
252 | static void mark_reg_death (); | |
253 | static void dump_conflicts (); | |
254 | void dump_global_regs (); | |
255 | static void find_reg (); | |
256 | static void global_conflicts (); | |
257 | static void expand_preferences (); | |
258 | static void prune_preferences (); | |
259 | static void record_conflicts (); | |
260 | static void set_preference (); | |
261 | \f | |
262 | /* Perform allocation of pseudo-registers not allocated by local_alloc. | |
263 | FILE is a file to output debugging information on, | |
264 | or zero if such output is not desired. */ | |
265 | ||
266 | void | |
267 | global_alloc (file) | |
268 | FILE *file; | |
269 | { | |
270 | #ifdef ELIMINABLE_REGS | |
271 | static struct {int from, to; } eliminables[] = ELIMINABLE_REGS; | |
272 | #endif | |
273 | register int i; | |
274 | rtx x; | |
275 | ||
276 | max_allocno = 0; | |
277 | ||
278 | /* A machine may have certain hard registers that | |
279 | are safe to use only within a basic block. */ | |
280 | ||
281 | CLEAR_HARD_REG_SET (no_global_alloc_regs); | |
282 | #ifdef OVERLAPPING_REGNO_P | |
283 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
284 | if (OVERLAPPING_REGNO_P (i)) | |
285 | SET_HARD_REG_BIT (no_global_alloc_regs, i); | |
286 | #endif | |
287 | ||
288 | /* Build the regset of all eliminable registers and show we can't use those | |
289 | that we already know won't be eliminated. */ | |
290 | #ifdef ELIMINABLE_REGS | |
291 | for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++) | |
292 | { | |
293 | SET_HARD_REG_BIT (eliminable_regset, eliminables[i].from); | |
294 | ||
295 | if (! CAN_ELIMINATE (eliminables[i].from, eliminables[i].to) | |
296 | || (eliminables[i].from == FRAME_POINTER_REGNUM | |
1d56e983 | 297 | && (! flag_omit_frame_pointer || FRAME_POINTER_REQUIRED))) |
38398762 RK |
298 | SET_HARD_REG_BIT (no_global_alloc_regs, eliminables[i].from); |
299 | } | |
300 | #else | |
301 | SET_HARD_REG_BIT (eliminable_regset, FRAME_POINTER_REGNUM); | |
302 | ||
303 | /* If we know we will definitely not be eliminating the frame pointer, | |
304 | don't allocate it. */ | |
1d56e983 | 305 | if (! flag_omit_frame_pointer || FRAME_POINTER_REQUIRED) |
38398762 RK |
306 | SET_HARD_REG_BIT (no_global_alloc_regs, FRAME_POINTER_REGNUM); |
307 | #endif | |
308 | ||
309 | /* Track which registers have already been used. Start with registers | |
310 | explicitly in the rtl, then registers allocated by local register | |
311 | allocation. | |
312 | ||
313 | We consider registers that do not have to be saved over calls as if | |
314 | they were already used since there is no cost in using them. */ | |
315 | ||
316 | CLEAR_HARD_REG_SET (regs_used_so_far); | |
317 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
318 | if (regs_ever_live[i] || call_used_regs[i]) | |
319 | SET_HARD_REG_BIT (regs_used_so_far, i); | |
320 | ||
321 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) | |
322 | if (reg_renumber[i] >= 0) | |
323 | SET_HARD_REG_BIT (regs_used_so_far, reg_renumber[i]); | |
324 | ||
325 | /* Establish mappings from register number to allocation number | |
326 | and vice versa. In the process, count the allocnos. */ | |
327 | ||
328 | reg_allocno = (int *) alloca (max_regno * sizeof (int)); | |
329 | ||
330 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
331 | reg_allocno[i] = -1; | |
332 | ||
333 | /* Initialize the shared-hard-reg mapping | |
334 | from the list of pairs that may share. */ | |
335 | reg_may_share = (int *) alloca (max_regno * sizeof (int)); | |
336 | bzero (reg_may_share, max_regno * sizeof (int)); | |
337 | for (x = regs_may_share; x; x = XEXP (XEXP (x, 1), 1)) | |
338 | { | |
339 | int r1 = REGNO (XEXP (x, 0)); | |
340 | int r2 = REGNO (XEXP (XEXP (x, 1), 0)); | |
341 | if (r1 > r2) | |
342 | reg_may_share[r1] = r2; | |
343 | else | |
344 | reg_may_share[r2] = r1; | |
345 | } | |
346 | ||
347 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) | |
348 | /* Note that reg_live_length[i] < 0 indicates a "constant" reg | |
349 | that we are supposed to refrain from putting in a hard reg. | |
350 | -2 means do make an allocno but don't allocate it. */ | |
351 | if (reg_n_refs[i] != 0 && reg_renumber[i] < 0 && reg_live_length[i] != -1 | |
352 | /* Don't allocate pseudos that cross calls, | |
353 | if this function receives a nonlocal goto. */ | |
354 | && (! current_function_has_nonlocal_label | |
355 | || reg_n_calls_crossed[i] == 0)) | |
356 | { | |
357 | if (reg_may_share[i] && reg_allocno[reg_may_share[i]] >= 0) | |
358 | reg_allocno[i] = reg_allocno[reg_may_share[i]]; | |
359 | else | |
360 | reg_allocno[i] = max_allocno++; | |
361 | if (reg_live_length[i] == 0) | |
362 | abort (); | |
363 | } | |
364 | else | |
365 | reg_allocno[i] = -1; | |
366 | ||
367 | allocno_reg = (int *) alloca (max_allocno * sizeof (int)); | |
368 | allocno_size = (int *) alloca (max_allocno * sizeof (int)); | |
369 | allocno_calls_crossed = (int *) alloca (max_allocno * sizeof (int)); | |
370 | allocno_n_refs = (int *) alloca (max_allocno * sizeof (int)); | |
371 | allocno_live_length = (int *) alloca (max_allocno * sizeof (int)); | |
372 | bzero (allocno_size, max_allocno * sizeof (int)); | |
373 | bzero (allocno_calls_crossed, max_allocno * sizeof (int)); | |
374 | bzero (allocno_n_refs, max_allocno * sizeof (int)); | |
375 | bzero (allocno_live_length, max_allocno * sizeof (int)); | |
376 | ||
377 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) | |
378 | if (reg_allocno[i] >= 0) | |
379 | { | |
380 | int allocno = reg_allocno[i]; | |
381 | allocno_reg[allocno] = i; | |
382 | allocno_size[allocno] = PSEUDO_REGNO_SIZE (i); | |
383 | allocno_calls_crossed[allocno] += reg_n_calls_crossed[i]; | |
384 | allocno_n_refs[allocno] += reg_n_refs[i]; | |
385 | if (allocno_live_length[allocno] < reg_live_length[i]) | |
386 | allocno_live_length[allocno] = reg_live_length[i]; | |
387 | } | |
388 | ||
1d56e983 RS |
389 | /* Calculate amount of usage of each hard reg by pseudos |
390 | allocated by local-alloc. This is to see if we want to | |
391 | override it. */ | |
392 | bzero (local_reg_live_length, sizeof local_reg_live_length); | |
393 | bzero (local_reg_n_refs, sizeof local_reg_n_refs); | |
394 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) | |
395 | if (reg_allocno[i] < 0 && reg_renumber[i] >= 0) | |
396 | { | |
397 | local_reg_n_refs[reg_renumber[i]] += reg_n_refs[i]; | |
398 | local_reg_live_length[reg_renumber[i]] += reg_live_length[i]; | |
399 | } | |
400 | /* We can't override local-alloc for a reg used not just by local-alloc. */ | |
401 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
402 | if (regs_ever_live[i]) | |
403 | local_reg_n_refs[i] = 0; | |
404 | ||
38398762 RK |
405 | /* Allocate the space for the conflict and preference tables and |
406 | initialize them. */ | |
407 | ||
408 | hard_reg_conflicts | |
409 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); | |
410 | bzero (hard_reg_conflicts, max_allocno * sizeof (HARD_REG_SET)); | |
411 | ||
412 | hard_reg_preferences | |
413 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); | |
414 | bzero (hard_reg_preferences, max_allocno * sizeof (HARD_REG_SET)); | |
415 | ||
416 | hard_reg_copy_preferences | |
417 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); | |
418 | bzero (hard_reg_copy_preferences, max_allocno * sizeof (HARD_REG_SET)); | |
419 | ||
420 | hard_reg_full_preferences | |
421 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); | |
422 | bzero (hard_reg_full_preferences, max_allocno * sizeof (HARD_REG_SET)); | |
423 | ||
424 | regs_someone_prefers | |
425 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); | |
426 | bzero (regs_someone_prefers, max_allocno * sizeof (HARD_REG_SET)); | |
427 | ||
428 | allocno_row_words = (max_allocno + INT_BITS - 1) / INT_BITS; | |
429 | ||
430 | conflicts = (int *) alloca (max_allocno * allocno_row_words * sizeof (int)); | |
431 | bzero (conflicts, max_allocno * allocno_row_words * sizeof (int)); | |
432 | ||
433 | allocnos_live = (int *) alloca (allocno_row_words * sizeof (int)); | |
434 | ||
435 | /* If there is work to be done (at least one reg to allocate), | |
436 | perform global conflict analysis and allocate the regs. */ | |
437 | ||
438 | if (max_allocno > 0) | |
439 | { | |
440 | /* Scan all the insns and compute the conflicts among allocnos | |
441 | and between allocnos and hard regs. */ | |
442 | ||
443 | global_conflicts (); | |
444 | ||
445 | /* Eliminate conflicts between pseudos and eliminable registers. If | |
446 | the register is not eliminated, the pseudo won't really be able to | |
447 | live in the eliminable register, so the conflict doesn't matter. | |
448 | If we do eliminate the register, the conflict will no longer exist. | |
1d56e983 RS |
449 | So in either case, we can ignore the conflict. Likewise for |
450 | preferences. */ | |
38398762 RK |
451 | |
452 | for (i = 0; i < max_allocno; i++) | |
1d56e983 RS |
453 | { |
454 | AND_COMPL_HARD_REG_SET (hard_reg_conflicts[i], eliminable_regset); | |
455 | AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[i], | |
456 | eliminable_regset); | |
457 | AND_COMPL_HARD_REG_SET (hard_reg_preferences[i], eliminable_regset); | |
458 | } | |
38398762 RK |
459 | |
460 | /* Try to expand the preferences by merging them between allocnos. */ | |
461 | ||
462 | expand_preferences (); | |
463 | ||
464 | /* Determine the order to allocate the remaining pseudo registers. */ | |
465 | ||
466 | allocno_order = (int *) alloca (max_allocno * sizeof (int)); | |
467 | for (i = 0; i < max_allocno; i++) | |
468 | allocno_order[i] = i; | |
469 | ||
470 | /* Default the size to 1, since allocno_compare uses it to divide by. | |
471 | Also convert allocno_live_length of zero to -1. A length of zero | |
472 | can occur when all the registers for that allocno have reg_live_length | |
473 | equal to -2. In this case, we want to make an allocno, but not | |
474 | allocate it. So avoid the divide-by-zero and set it to a low | |
475 | priority. */ | |
476 | ||
477 | for (i = 0; i < max_allocno; i++) | |
478 | { | |
479 | if (allocno_size[i] == 0) | |
480 | allocno_size[i] = 1; | |
481 | if (allocno_live_length[i] == 0) | |
482 | allocno_live_length[i] = -1; | |
483 | } | |
484 | ||
485 | qsort (allocno_order, max_allocno, sizeof (int), allocno_compare); | |
486 | ||
487 | prune_preferences (); | |
488 | ||
489 | if (file) | |
490 | dump_conflicts (file); | |
491 | ||
492 | /* Try allocating them, one by one, in that order, | |
493 | except for parameters marked with reg_live_length[regno] == -2. */ | |
494 | ||
495 | for (i = 0; i < max_allocno; i++) | |
496 | if (reg_live_length[allocno_reg[allocno_order[i]]] >= 0) | |
497 | { | |
498 | /* If we have more than one register class, | |
499 | first try allocating in the class that is cheapest | |
500 | for this pseudo-reg. If that fails, try any reg. */ | |
501 | if (N_REG_CLASSES > 1) | |
502 | { | |
1d56e983 | 503 | find_reg (allocno_order[i], HARD_CONST (0), 0, 0, 0); |
38398762 RK |
504 | if (reg_renumber[allocno_reg[allocno_order[i]]] >= 0) |
505 | continue; | |
506 | } | |
507 | if (!reg_preferred_or_nothing (allocno_reg[allocno_order[i]])) | |
1d56e983 | 508 | find_reg (allocno_order[i], HARD_CONST (0), 1, 0, 0); |
38398762 RK |
509 | } |
510 | } | |
511 | ||
512 | /* Do the reloads now while the allocno data still exist, so that we can | |
513 | try to assign new hard regs to any pseudo regs that are spilled. */ | |
514 | ||
515 | if (n_basic_blocks > 0) | |
516 | reload (basic_block_head[0], 1, file); | |
517 | } | |
518 | ||
519 | /* Sort predicate for ordering the allocnos. | |
520 | Returns -1 (1) if *v1 should be allocated before (after) *v2. */ | |
521 | ||
522 | static int | |
523 | allocno_compare (v1, v2) | |
524 | int *v1, *v2; | |
525 | { | |
526 | /* Note that the quotient will never be bigger than | |
527 | the value of floor_log2 times the maximum number of | |
528 | times a register can occur in one insn (surely less than 100). | |
529 | Multiplying this by 10000 can't overflow. */ | |
530 | register int pri1 | |
531 | = (((double) (floor_log2 (allocno_n_refs[*v1]) * allocno_n_refs[*v1]) | |
532 | / (allocno_live_length[*v1] * allocno_size[*v1])) | |
533 | * 10000); | |
534 | register int pri2 | |
535 | = (((double) (floor_log2 (allocno_n_refs[*v2]) * allocno_n_refs[*v2]) | |
536 | / (allocno_live_length[*v2] * allocno_size[*v2])) | |
537 | * 10000); | |
538 | if (pri2 - pri1) | |
539 | return pri2 - pri1; | |
540 | ||
541 | /* If regs are equally good, sort by allocno, | |
542 | so that the results of qsort leave nothing to chance. */ | |
543 | return *v1 - *v2; | |
544 | } | |
545 | \f | |
546 | /* Scan the rtl code and record all conflicts and register preferences in the | |
547 | conflict matrices and preference tables. */ | |
548 | ||
549 | static void | |
550 | global_conflicts () | |
551 | { | |
552 | register int b, i; | |
553 | register rtx insn; | |
554 | short *block_start_allocnos; | |
555 | ||
556 | /* Make a vector that mark_reg_{store,clobber} will store in. */ | |
557 | regs_set = (rtx *) alloca (max_parallel * sizeof (rtx) * 2); | |
558 | ||
559 | block_start_allocnos = (short *) alloca (max_allocno * sizeof (short)); | |
560 | ||
561 | for (b = 0; b < n_basic_blocks; b++) | |
562 | { | |
563 | bzero (allocnos_live, allocno_row_words * sizeof (int)); | |
564 | ||
565 | /* Initialize table of registers currently live | |
566 | to the state at the beginning of this basic block. | |
567 | This also marks the conflicts among them. | |
568 | ||
569 | For pseudo-regs, there is only one bit for each one | |
570 | no matter how many hard regs it occupies. | |
571 | This is ok; we know the size from PSEUDO_REGNO_SIZE. | |
572 | For explicit hard regs, we cannot know the size that way | |
573 | since one hard reg can be used with various sizes. | |
574 | Therefore, we must require that all the hard regs | |
575 | implicitly live as part of a multi-word hard reg | |
576 | are explicitly marked in basic_block_live_at_start. */ | |
577 | ||
578 | { | |
579 | register int offset, bit; | |
580 | register regset old = basic_block_live_at_start[b]; | |
581 | int ax = 0; | |
582 | ||
583 | #ifdef HARD_REG_SET | |
584 | hard_regs_live = old[0]; | |
585 | #else | |
586 | COPY_HARD_REG_SET (hard_regs_live, old); | |
587 | #endif | |
588 | for (offset = 0, i = 0; offset < regset_size; offset++) | |
589 | if (old[offset] == 0) | |
590 | i += HOST_BITS_PER_INT; | |
591 | else | |
592 | for (bit = 1; bit; bit <<= 1, i++) | |
593 | { | |
594 | if (i >= max_regno) | |
595 | break; | |
596 | if (old[offset] & bit) | |
597 | { | |
598 | register int a = reg_allocno[i]; | |
599 | if (a >= 0) | |
600 | { | |
601 | SET_ALLOCNO_LIVE (a); | |
602 | block_start_allocnos[ax++] = a; | |
603 | } | |
604 | else if ((a = reg_renumber[i]) >= 0) | |
605 | mark_reg_live_nc (a, PSEUDO_REGNO_MODE (i)); | |
606 | } | |
607 | } | |
608 | ||
609 | /* Record that each allocno now live conflicts with each other | |
610 | allocno now live, and with each hard reg now live. */ | |
611 | ||
612 | record_conflicts (block_start_allocnos, ax); | |
613 | } | |
614 | ||
615 | insn = basic_block_head[b]; | |
616 | ||
617 | /* Scan the code of this basic block, noting which allocnos | |
618 | and hard regs are born or die. When one is born, | |
619 | record a conflict with all others currently live. */ | |
620 | ||
621 | while (1) | |
622 | { | |
623 | register RTX_CODE code = GET_CODE (insn); | |
624 | register rtx link; | |
625 | ||
626 | /* Make regs_set an empty set. */ | |
627 | ||
628 | n_regs_set = 0; | |
629 | ||
630 | if (code == INSN || code == CALL_INSN || code == JUMP_INSN) | |
631 | { | |
632 | int i = 0; | |
633 | ||
634 | #if 0 | |
635 | for (link = REG_NOTES (insn); | |
636 | link && i < NUM_NO_CONFLICT_PAIRS; | |
637 | link = XEXP (link, 1)) | |
638 | if (REG_NOTE_KIND (link) == REG_NO_CONFLICT) | |
639 | { | |
640 | no_conflict_pairs[i].allocno1 | |
641 | = reg_allocno[REGNO (SET_DEST (PATTERN (insn)))]; | |
642 | no_conflict_pairs[i].allocno2 | |
643 | = reg_allocno[REGNO (XEXP (link, 0))]; | |
644 | i++; | |
645 | } | |
646 | #endif /* 0 */ | |
647 | ||
648 | /* Mark any registers clobbered by INSN as live, | |
649 | so they conflict with the inputs. */ | |
650 | ||
651 | note_stores (PATTERN (insn), mark_reg_clobber); | |
652 | ||
653 | /* Mark any registers dead after INSN as dead now. */ | |
654 | ||
655 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
656 | if (REG_NOTE_KIND (link) == REG_DEAD) | |
657 | mark_reg_death (XEXP (link, 0)); | |
658 | ||
659 | /* Mark any registers set in INSN as live, | |
660 | and mark them as conflicting with all other live regs. | |
661 | Clobbers are processed again, so they conflict with | |
662 | the registers that are set. */ | |
663 | ||
664 | note_stores (PATTERN (insn), mark_reg_store); | |
665 | ||
666 | #ifdef AUTO_INC_DEC | |
667 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
668 | if (REG_NOTE_KIND (link) == REG_INC) | |
669 | mark_reg_store (XEXP (link, 0), 0); | |
670 | #endif | |
671 | ||
672 | /* Mark any registers set in INSN and then never used. */ | |
673 | ||
674 | while (n_regs_set > 0) | |
675 | if (find_regno_note (insn, REG_UNUSED, | |
676 | REGNO (regs_set[--n_regs_set]))) | |
677 | mark_reg_death (regs_set[n_regs_set]); | |
678 | } | |
679 | ||
680 | if (insn == basic_block_end[b]) | |
681 | break; | |
682 | insn = NEXT_INSN (insn); | |
683 | } | |
684 | } | |
685 | } | |
686 | /* Expand the preference information by looking for cases where one allocno | |
687 | dies in an insn that sets an allocno. If those two allocnos don't conflict, | |
688 | merge any preferences between those allocnos. */ | |
689 | ||
690 | static void | |
691 | expand_preferences () | |
692 | { | |
693 | rtx insn; | |
694 | rtx link; | |
695 | rtx set; | |
696 | ||
697 | /* We only try to handle the most common cases here. Most of the cases | |
698 | where this wins are reg-reg copies. */ | |
699 | ||
700 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
701 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' | |
702 | && (set = single_set (insn)) != 0 | |
703 | && GET_CODE (SET_DEST (set)) == REG | |
704 | && reg_allocno[REGNO (SET_DEST (set))] >= 0) | |
705 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
706 | if (REG_NOTE_KIND (link) == REG_DEAD | |
707 | && GET_CODE (XEXP (link, 0)) == REG | |
708 | && reg_allocno[REGNO (XEXP (link, 0))] >= 0 | |
709 | && ! CONFLICTP (reg_allocno[REGNO (SET_DEST (set))], | |
710 | reg_allocno[REGNO (XEXP (link, 0))]) | |
711 | && ! CONFLICTP (reg_allocno[REGNO (XEXP (link, 0))], | |
712 | reg_allocno[REGNO (SET_DEST (set))])) | |
713 | { | |
714 | int a1 = reg_allocno[REGNO (SET_DEST (set))]; | |
715 | int a2 = reg_allocno[REGNO (XEXP (link, 0))]; | |
716 | ||
717 | if (XEXP (link, 0) == SET_SRC (set)) | |
718 | { | |
719 | IOR_HARD_REG_SET (hard_reg_copy_preferences[a1], | |
720 | hard_reg_copy_preferences[a2]); | |
721 | IOR_HARD_REG_SET (hard_reg_copy_preferences[a2], | |
722 | hard_reg_copy_preferences[a1]); | |
723 | } | |
724 | ||
725 | IOR_HARD_REG_SET (hard_reg_preferences[a1], | |
726 | hard_reg_preferences[a2]); | |
727 | IOR_HARD_REG_SET (hard_reg_preferences[a2], | |
728 | hard_reg_preferences[a1]); | |
729 | IOR_HARD_REG_SET (hard_reg_full_preferences[a1], | |
730 | hard_reg_full_preferences[a2]); | |
731 | IOR_HARD_REG_SET (hard_reg_full_preferences[a2], | |
732 | hard_reg_full_preferences[a1]); | |
733 | } | |
734 | } | |
735 | \f | |
736 | /* Prune the preferences for global registers to exclude registers that cannot | |
737 | be used. | |
738 | ||
739 | Compute `regs_someone_prefers', which is a bitmask of the hard registers | |
740 | that are preferred by conflicting registers of lower priority. If possible, | |
741 | we will avoid using these registers. */ | |
742 | ||
743 | static void | |
744 | prune_preferences () | |
745 | { | |
746 | int i, j; | |
747 | int allocno; | |
748 | ||
749 | /* Scan least most important to most important. | |
750 | For each allocno, remove from preferences registers that cannot be used, | |
751 | either because of conflicts or register type. Then compute all registers | |
752 | prefered by each lower-priority register that conflicts. */ | |
753 | ||
754 | for (i = max_allocno - 1; i >= 0; i--) | |
755 | { | |
756 | HARD_REG_SET temp; | |
757 | ||
758 | allocno = allocno_order[i]; | |
759 | COPY_HARD_REG_SET (temp, hard_reg_conflicts[allocno]); | |
760 | ||
761 | if (allocno_calls_crossed[allocno] == 0) | |
762 | IOR_HARD_REG_SET (temp, fixed_reg_set); | |
763 | else | |
764 | IOR_HARD_REG_SET (temp, call_used_reg_set); | |
765 | ||
766 | IOR_COMPL_HARD_REG_SET | |
767 | (temp, | |
768 | reg_class_contents[(int) reg_preferred_class (allocno_reg[allocno])]); | |
769 | ||
770 | AND_COMPL_HARD_REG_SET (hard_reg_preferences[allocno], temp); | |
771 | AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[allocno], temp); | |
772 | AND_COMPL_HARD_REG_SET (hard_reg_full_preferences[allocno], temp); | |
773 | ||
774 | CLEAR_HARD_REG_SET (regs_someone_prefers[allocno]); | |
775 | ||
776 | /* Merge in the preferences of lower-priority registers (they have | |
777 | already been pruned). If we also prefer some of those registers, | |
778 | don't exclude them unless we are of a smaller size (in which case | |
779 | we want to give the lower-priority allocno the first chance for | |
780 | these registers). */ | |
781 | for (j = i + 1; j < max_allocno; j++) | |
782 | if (CONFLICTP (allocno, allocno_order[j])) | |
783 | { | |
784 | COPY_HARD_REG_SET (temp, | |
785 | hard_reg_full_preferences[allocno_order[j]]); | |
786 | if (allocno_size[allocno_order[j]] <= allocno_size[allocno]) | |
787 | AND_COMPL_HARD_REG_SET (temp, | |
788 | hard_reg_full_preferences[allocno]); | |
789 | ||
790 | IOR_HARD_REG_SET (regs_someone_prefers[allocno], temp); | |
791 | } | |
792 | } | |
793 | } | |
794 | \f | |
795 | /* Assign a hard register to ALLOCNO; look for one that is the beginning | |
796 | of a long enough stretch of hard regs none of which conflicts with ALLOCNO. | |
797 | The registers marked in PREFREGS are tried first. | |
798 | ||
799 | LOSERS, if non-zero, is a HARD_REG_SET indicating registers that cannot | |
800 | be used for this allocation. | |
801 | ||
802 | If ALL_REGS_P is zero, consider only the preferred class of ALLOCNO's reg. | |
803 | Otherwise ignore that preferred class. | |
804 | ||
805 | If ACCEPT_CALL_CLOBBERED is nonzero, accept a call-clobbered hard reg that | |
806 | will have to be saved and restored at calls. | |
807 | ||
1d56e983 RS |
808 | RETRYING is nonzero if this is called from retry_global_alloc. |
809 | ||
38398762 RK |
810 | If we find one, record it in reg_renumber. |
811 | If not, do nothing. */ | |
812 | ||
813 | static void | |
1d56e983 | 814 | find_reg (allocno, losers, all_regs_p, accept_call_clobbered, retrying) |
38398762 RK |
815 | int allocno; |
816 | HARD_REG_SET losers; | |
817 | int all_regs_p; | |
818 | int accept_call_clobbered; | |
1d56e983 | 819 | int retrying; |
38398762 RK |
820 | { |
821 | register int i, best_reg, pass; | |
822 | #ifdef HARD_REG_SET | |
823 | register /* Declare it register if it's a scalar. */ | |
824 | #endif | |
1d56e983 | 825 | HARD_REG_SET used, used1, used2; |
38398762 RK |
826 | |
827 | enum reg_class class | |
828 | = all_regs_p ? ALL_REGS : reg_preferred_class (allocno_reg[allocno]); | |
829 | enum machine_mode mode = PSEUDO_REGNO_MODE (allocno_reg[allocno]); | |
830 | ||
831 | if (accept_call_clobbered) | |
832 | COPY_HARD_REG_SET (used1, call_fixed_reg_set); | |
833 | else if (allocno_calls_crossed[allocno] == 0) | |
834 | COPY_HARD_REG_SET (used1, fixed_reg_set); | |
835 | else | |
836 | COPY_HARD_REG_SET (used1, call_used_reg_set); | |
837 | ||
838 | /* Some registers should not be allocated in global-alloc. */ | |
839 | IOR_HARD_REG_SET (used1, no_global_alloc_regs); | |
840 | if (losers) | |
841 | IOR_HARD_REG_SET (used1, losers); | |
842 | ||
843 | IOR_COMPL_HARD_REG_SET (used1, reg_class_contents[(int) class]); | |
1d56e983 RS |
844 | COPY_HARD_REG_SET (used2, used1); |
845 | ||
38398762 RK |
846 | IOR_HARD_REG_SET (used1, hard_reg_conflicts[allocno]); |
847 | ||
848 | /* Try each hard reg to see if it fits. Do this in two passes. | |
849 | In the first pass, skip registers that are prefered by some other pseudo | |
850 | to give it a better chance of getting one of those registers. Only if | |
851 | we can't get a register when excluding those do we take one of them. | |
852 | However, we never allocate a register for the first time in pass 0. */ | |
853 | ||
854 | COPY_HARD_REG_SET (used, used1); | |
855 | IOR_COMPL_HARD_REG_SET (used, regs_used_so_far); | |
856 | IOR_HARD_REG_SET (used, regs_someone_prefers[allocno]); | |
857 | ||
858 | best_reg = -1; | |
859 | for (i = FIRST_PSEUDO_REGISTER, pass = 0; | |
860 | pass <= 1 && i >= FIRST_PSEUDO_REGISTER; | |
861 | pass++) | |
862 | { | |
863 | if (pass == 1) | |
864 | COPY_HARD_REG_SET (used, used1); | |
865 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
866 | { | |
867 | #ifdef REG_ALLOC_ORDER | |
868 | int regno = reg_alloc_order[i]; | |
869 | #else | |
870 | int regno = i; | |
871 | #endif | |
872 | if (! TEST_HARD_REG_BIT (used, regno) | |
873 | && HARD_REGNO_MODE_OK (regno, mode)) | |
874 | { | |
875 | register int j; | |
876 | register int lim = regno + HARD_REGNO_NREGS (regno, mode); | |
877 | for (j = regno + 1; | |
878 | (j < lim | |
879 | && ! TEST_HARD_REG_BIT (used, j)); | |
880 | j++); | |
881 | if (j == lim) | |
882 | { | |
883 | best_reg = regno; | |
884 | break; | |
885 | } | |
886 | #ifndef REG_ALLOC_ORDER | |
887 | i = j; /* Skip starting points we know will lose */ | |
888 | #endif | |
889 | } | |
890 | } | |
891 | } | |
892 | ||
893 | /* See if there is a preferred register with the same class as the register | |
894 | we allocated above. Making this restriction prevents register | |
895 | preferencing from creating worse register allocation. | |
896 | ||
897 | Remove from the preferred registers and conflicting registers. Note that | |
898 | additional conflicts may have been added after `prune_preferences' was | |
899 | called. | |
900 | ||
901 | First do this for those register with copy preferences, then all | |
902 | preferred registers. */ | |
903 | ||
904 | AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[allocno], used); | |
905 | GO_IF_HARD_REG_SUBSET (hard_reg_copy_preferences[allocno], | |
906 | reg_class_contents[(int) NO_REGS], no_copy_prefs); | |
907 | ||
908 | if (best_reg >= 0) | |
909 | { | |
910 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
911 | if (TEST_HARD_REG_BIT (hard_reg_copy_preferences[allocno], i) | |
912 | && HARD_REGNO_MODE_OK (i, mode) | |
913 | && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg) | |
914 | || reg_class_subset_p (REGNO_REG_CLASS (i), | |
915 | REGNO_REG_CLASS (best_reg)) | |
916 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg), | |
917 | REGNO_REG_CLASS (i)))) | |
918 | { | |
919 | register int j; | |
920 | register int lim = i + HARD_REGNO_NREGS (i, mode); | |
921 | for (j = i + 1; | |
922 | (j < lim | |
923 | && ! TEST_HARD_REG_BIT (used, j) | |
924 | && (REGNO_REG_CLASS (j) | |
925 | == REGNO_REG_CLASS (best_reg + (j - i)) | |
926 | || reg_class_subset_p (REGNO_REG_CLASS (j), | |
927 | REGNO_REG_CLASS (best_reg + (j - i))) | |
928 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)), | |
929 | REGNO_REG_CLASS (j)))); | |
930 | j++); | |
931 | if (j == lim) | |
932 | { | |
933 | best_reg = i; | |
934 | goto no_prefs; | |
935 | } | |
936 | } | |
937 | } | |
938 | no_copy_prefs: | |
939 | ||
940 | AND_COMPL_HARD_REG_SET (hard_reg_preferences[allocno], used); | |
941 | GO_IF_HARD_REG_SUBSET (hard_reg_preferences[allocno], | |
942 | reg_class_contents[(int) NO_REGS], no_prefs); | |
943 | ||
944 | if (best_reg >= 0) | |
945 | { | |
946 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
947 | if (TEST_HARD_REG_BIT (hard_reg_preferences[allocno], i) | |
948 | && HARD_REGNO_MODE_OK (i, mode) | |
949 | && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg) | |
950 | || reg_class_subset_p (REGNO_REG_CLASS (i), | |
951 | REGNO_REG_CLASS (best_reg)) | |
952 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg), | |
953 | REGNO_REG_CLASS (i)))) | |
954 | { | |
955 | register int j; | |
956 | register int lim = i + HARD_REGNO_NREGS (i, mode); | |
957 | for (j = i + 1; | |
958 | (j < lim | |
959 | && ! TEST_HARD_REG_BIT (used, j) | |
960 | && (REGNO_REG_CLASS (j) | |
961 | == REGNO_REG_CLASS (best_reg + (j - i)) | |
962 | || reg_class_subset_p (REGNO_REG_CLASS (j), | |
963 | REGNO_REG_CLASS (best_reg + (j - i))) | |
964 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)), | |
965 | REGNO_REG_CLASS (j)))); | |
966 | j++); | |
967 | if (j == lim) | |
968 | { | |
969 | best_reg = i; | |
970 | break; | |
971 | } | |
972 | } | |
973 | } | |
974 | no_prefs: | |
975 | ||
1d56e983 RS |
976 | /* If we haven't succeeded yet, try with caller-saves. */ |
977 | if (flag_caller_saves && best_reg < 0) | |
978 | { | |
979 | /* Did not find a register. If it would be profitable to | |
980 | allocate a call-clobbered register and save and restore it | |
981 | around calls, do that. */ | |
982 | if (! accept_call_clobbered | |
983 | && allocno_calls_crossed[allocno] != 0 | |
984 | && CALLER_SAVE_PROFITABLE (allocno_n_refs[allocno], | |
985 | allocno_calls_crossed[allocno])) | |
986 | { | |
987 | find_reg (allocno, losers, all_regs_p, 1, retrying); | |
988 | if (reg_renumber[allocno_reg[allocno]] >= 0) | |
989 | { | |
990 | caller_save_needed = 1; | |
991 | return; | |
992 | } | |
993 | } | |
994 | } | |
995 | ||
996 | /* If we haven't succeeded yet, | |
997 | see if some hard reg that conflicts with us | |
998 | was utilized poorly by local-alloc. | |
999 | If so, kick out the regs that were put there by local-alloc | |
1000 | so we can use it instead. */ | |
1001 | if (best_reg < 0 && !retrying | |
1002 | /* Let's not bother with multi-reg allocnos. */ | |
1003 | && allocno_size[allocno] == 1) | |
1004 | { | |
1005 | /* Count from the end, to find the least-used ones first. */ | |
1006 | for (i = FIRST_PSEUDO_REGISTER - 1; i >= 0; i--) | |
1007 | if (local_reg_n_refs[i] != 0 | |
1008 | /* Don't use a reg no good for this pseudo. */ | |
1009 | && ! TEST_HARD_REG_BIT (used2, i) | |
1010 | && HARD_REGNO_MODE_OK (i, mode) | |
1011 | && ((double) local_reg_n_refs[i] / local_reg_live_length[i] | |
1012 | < ((double) allocno_n_refs[allocno] | |
1013 | / allocno_live_length[allocno]))) | |
1014 | { | |
1015 | /* Hard reg I was used less in total by local regs | |
1016 | than it would be used by this one allocno! */ | |
1017 | int k; | |
1018 | for (k = 0; k < max_regno; k++) | |
1019 | if (reg_renumber[k] == i) | |
1020 | reg_renumber[k] = -1; | |
1021 | best_reg = i; | |
1022 | break; | |
1023 | } | |
1024 | } | |
1025 | ||
38398762 RK |
1026 | /* Did we find a register? */ |
1027 | ||
1028 | if (best_reg >= 0) | |
1029 | { | |
1030 | register int lim, j; | |
1031 | HARD_REG_SET this_reg; | |
1032 | ||
1033 | /* Yes. Record it as the hard register of this pseudo-reg. */ | |
1034 | reg_renumber[allocno_reg[allocno]] = best_reg; | |
1035 | /* Also of any pseudo-regs that share with it. */ | |
1036 | if (reg_may_share[allocno_reg[allocno]]) | |
1037 | for (j = FIRST_PSEUDO_REGISTER; j < max_regno; j++) | |
1038 | if (reg_allocno[j] == allocno) | |
1039 | reg_renumber[j] = best_reg; | |
1040 | ||
1041 | /* Make a set of the hard regs being allocated. */ | |
1042 | CLEAR_HARD_REG_SET (this_reg); | |
1043 | lim = best_reg + HARD_REGNO_NREGS (best_reg, mode); | |
1044 | for (j = best_reg; j < lim; j++) | |
1045 | { | |
1046 | SET_HARD_REG_BIT (this_reg, j); | |
1047 | SET_HARD_REG_BIT (regs_used_so_far, j); | |
1d56e983 RS |
1048 | /* This is no longer a reg used just by local regs. */ |
1049 | local_reg_n_refs[j] = 0; | |
38398762 RK |
1050 | } |
1051 | /* For each other pseudo-reg conflicting with this one, | |
1052 | mark it as conflicting with the hard regs this one occupies. */ | |
1053 | lim = allocno; | |
1054 | for (j = 0; j < max_allocno; j++) | |
1055 | if (CONFLICTP (lim, j) || CONFLICTP (j, lim)) | |
1056 | { | |
1057 | IOR_HARD_REG_SET (hard_reg_conflicts[j], this_reg); | |
1058 | } | |
1059 | } | |
38398762 RK |
1060 | } |
1061 | \f | |
1062 | /* Called from `reload' to look for a hard reg to put pseudo reg REGNO in. | |
1063 | Perhaps it had previously seemed not worth a hard reg, | |
1064 | or perhaps its old hard reg has been commandeered for reloads. | |
1065 | FORBIDDEN_REGS indicates certain hard regs that may not be used, even if | |
1066 | they do not appear to be allocated. | |
1067 | If FORBIDDEN_REGS is zero, no regs are forbidden. */ | |
1068 | ||
1069 | void | |
1070 | retry_global_alloc (regno, forbidden_regs) | |
1071 | int regno; | |
1072 | HARD_REG_SET forbidden_regs; | |
1073 | { | |
1074 | int allocno = reg_allocno[regno]; | |
1075 | if (allocno >= 0) | |
1076 | { | |
1077 | /* If we have more than one register class, | |
1078 | first try allocating in the class that is cheapest | |
1079 | for this pseudo-reg. If that fails, try any reg. */ | |
1080 | if (N_REG_CLASSES > 1) | |
1d56e983 | 1081 | find_reg (allocno, forbidden_regs, 0, 0, 1); |
38398762 RK |
1082 | if (reg_renumber[regno] < 0 |
1083 | && !reg_preferred_or_nothing (regno)) | |
1d56e983 | 1084 | find_reg (allocno, forbidden_regs, 1, 0, 1); |
38398762 RK |
1085 | |
1086 | /* If we found a register, modify the RTL for the register to | |
1087 | show the hard register, and mark that register live. */ | |
1088 | if (reg_renumber[regno] >= 0) | |
1089 | { | |
1090 | REGNO (regno_reg_rtx[regno]) = reg_renumber[regno]; | |
1091 | mark_home_live (regno); | |
1092 | } | |
1093 | } | |
1094 | } | |
1095 | \f | |
1096 | /* Record a conflict between register REGNO | |
1097 | and everything currently live. | |
1098 | REGNO must not be a pseudo reg that was allocated | |
1099 | by local_alloc; such numbers must be translated through | |
1100 | reg_renumber before calling here. */ | |
1101 | ||
1102 | static void | |
1103 | record_one_conflict (regno) | |
1104 | int regno; | |
1105 | { | |
1106 | register int j; | |
1107 | ||
1108 | if (regno < FIRST_PSEUDO_REGISTER) | |
1109 | /* When a hard register becomes live, | |
1110 | record conflicts with live pseudo regs. */ | |
1111 | for (j = 0; j < max_allocno; j++) | |
1112 | { | |
1113 | if (ALLOCNO_LIVE_P (j)) | |
1114 | SET_HARD_REG_BIT (hard_reg_conflicts[j], regno); | |
1115 | } | |
1116 | else | |
1117 | /* When a pseudo-register becomes live, | |
1118 | record conflicts first with hard regs, | |
1119 | then with other pseudo regs. */ | |
1120 | { | |
1121 | register int ialloc = reg_allocno[regno]; | |
1122 | register int ialloc_prod = ialloc * allocno_row_words; | |
1123 | IOR_HARD_REG_SET (hard_reg_conflicts[ialloc], hard_regs_live); | |
1124 | for (j = allocno_row_words - 1; j >= 0; j--) | |
1125 | { | |
1126 | #if 0 | |
1127 | int k; | |
1128 | for (k = 0; k < n_no_conflict_pairs; k++) | |
1129 | if (! ((j == no_conflict_pairs[k].allocno1 | |
1130 | && ialloc == no_conflict_pairs[k].allocno2) | |
1131 | || | |
1132 | (j == no_conflict_pairs[k].allocno2 | |
1133 | && ialloc == no_conflict_pairs[k].allocno1))) | |
1134 | #endif /* 0 */ | |
1135 | conflicts[ialloc_prod + j] |= allocnos_live[j]; | |
1136 | } | |
1137 | } | |
1138 | } | |
1139 | ||
1140 | /* Record all allocnos currently live as conflicting | |
1141 | with each other and with all hard regs currently live. | |
1142 | ALLOCNO_VEC is a vector of LEN allocnos, all allocnos that | |
1143 | are currently live. Their bits are also flagged in allocnos_live. */ | |
1144 | ||
1145 | static void | |
1146 | record_conflicts (allocno_vec, len) | |
1147 | register short *allocno_vec; | |
1148 | register int len; | |
1149 | { | |
1150 | register int allocno; | |
1151 | register int j; | |
1152 | register int ialloc_prod; | |
1153 | ||
1154 | while (--len >= 0) | |
1155 | { | |
1156 | allocno = allocno_vec[len]; | |
1157 | ialloc_prod = allocno * allocno_row_words; | |
1158 | IOR_HARD_REG_SET (hard_reg_conflicts[allocno], hard_regs_live); | |
1159 | for (j = allocno_row_words - 1; j >= 0; j--) | |
1160 | conflicts[ialloc_prod + j] |= allocnos_live[j]; | |
1161 | } | |
1162 | } | |
1163 | \f | |
1164 | /* Handle the case where REG is set by the insn being scanned, | |
1165 | during the forward scan to accumulate conflicts. | |
1166 | Store a 1 in regs_live or allocnos_live for this register, record how many | |
1167 | consecutive hardware registers it actually needs, | |
1168 | and record a conflict with all other registers already live. | |
1169 | ||
1170 | Note that even if REG does not remain alive after this insn, | |
1171 | we must mark it here as live, to ensure a conflict between | |
1172 | REG and any other regs set in this insn that really do live. | |
1173 | This is because those other regs could be considered after this. | |
1174 | ||
1175 | REG might actually be something other than a register; | |
1176 | if so, we do nothing. | |
1177 | ||
1178 | SETTER is 0 if this register was modified by an auto-increment (i.e., | |
1179 | a REG_INC note was found for it). | |
1180 | ||
1181 | CLOBBERs are processed here by calling mark_reg_clobber. */ | |
1182 | ||
1183 | static void | |
1184 | mark_reg_store (orig_reg, setter) | |
1185 | rtx orig_reg, setter; | |
1186 | { | |
1187 | register int regno; | |
1188 | register rtx reg = orig_reg; | |
1189 | ||
1190 | /* WORD is which word of a multi-register group is being stored. | |
1191 | For the case where the store is actually into a SUBREG of REG. | |
1192 | Except we don't use it; I believe the entire REG needs to be | |
1193 | made live. */ | |
1194 | int word = 0; | |
1195 | ||
1196 | if (GET_CODE (reg) == SUBREG) | |
1197 | { | |
1198 | word = SUBREG_WORD (reg); | |
1199 | reg = SUBREG_REG (reg); | |
1200 | } | |
1201 | ||
1202 | if (GET_CODE (reg) != REG) | |
1203 | return; | |
1204 | ||
1205 | if (setter && GET_CODE (setter) == CLOBBER) | |
1206 | { | |
1207 | /* A clobber of a register should be processed here too. */ | |
1208 | mark_reg_clobber (orig_reg, setter); | |
1209 | return; | |
1210 | } | |
1211 | ||
1212 | regs_set[n_regs_set++] = reg; | |
1213 | ||
1214 | if (setter) | |
1215 | set_preference (reg, SET_SRC (setter)); | |
1216 | ||
1217 | regno = REGNO (reg); | |
1218 | ||
1219 | if (reg_renumber[regno] >= 0) | |
1220 | regno = reg_renumber[regno] /* + word */; | |
1221 | ||
1222 | /* Either this is one of the max_allocno pseudo regs not allocated, | |
1223 | or it is or has a hardware reg. First handle the pseudo-regs. */ | |
1224 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1225 | { | |
1226 | if (reg_allocno[regno] >= 0) | |
1227 | { | |
1228 | SET_ALLOCNO_LIVE (reg_allocno[regno]); | |
1229 | record_one_conflict (regno); | |
1230 | } | |
1231 | } | |
1232 | /* Handle hardware regs (and pseudos allocated to hard regs). */ | |
1233 | else if (! fixed_regs[regno]) | |
1234 | { | |
1235 | register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
1236 | while (regno < last) | |
1237 | { | |
1238 | record_one_conflict (regno); | |
1239 | SET_HARD_REG_BIT (hard_regs_live, regno); | |
1240 | regno++; | |
1241 | } | |
1242 | } | |
1243 | } | |
1244 | \f | |
1245 | /* Like mark_reg_set except notice just CLOBBERs; ignore SETs. */ | |
1246 | ||
1247 | static void | |
1248 | mark_reg_clobber (reg, setter) | |
1249 | rtx reg, setter; | |
1250 | { | |
1251 | register int regno; | |
1252 | ||
1253 | /* WORD is which word of a multi-register group is being stored. | |
1254 | For the case where the store is actually into a SUBREG of REG. | |
1255 | Except we don't use it; I believe the entire REG needs to be | |
1256 | made live. */ | |
1257 | int word = 0; | |
1258 | ||
1259 | if (GET_CODE (setter) != CLOBBER) | |
1260 | return; | |
1261 | ||
1262 | if (GET_CODE (reg) == SUBREG) | |
1263 | { | |
1264 | word = SUBREG_WORD (reg); | |
1265 | reg = SUBREG_REG (reg); | |
1266 | } | |
1267 | ||
1268 | if (GET_CODE (reg) != REG) | |
1269 | return; | |
1270 | ||
1271 | regs_set[n_regs_set++] = reg; | |
1272 | ||
1273 | regno = REGNO (reg); | |
1274 | ||
1275 | if (reg_renumber[regno] >= 0) | |
1276 | regno = reg_renumber[regno] /* + word */; | |
1277 | ||
1278 | /* Either this is one of the max_allocno pseudo regs not allocated, | |
1279 | or it is or has a hardware reg. First handle the pseudo-regs. */ | |
1280 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1281 | { | |
1282 | if (reg_allocno[regno] >= 0) | |
1283 | { | |
1284 | SET_ALLOCNO_LIVE (reg_allocno[regno]); | |
1285 | record_one_conflict (regno); | |
1286 | } | |
1287 | } | |
1288 | /* Handle hardware regs (and pseudos allocated to hard regs). */ | |
1289 | else if (! fixed_regs[regno]) | |
1290 | { | |
1291 | register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
1292 | while (regno < last) | |
1293 | { | |
1294 | record_one_conflict (regno); | |
1295 | SET_HARD_REG_BIT (hard_regs_live, regno); | |
1296 | regno++; | |
1297 | } | |
1298 | } | |
1299 | } | |
1300 | \f | |
1301 | /* Mark REG as being dead (following the insn being scanned now). | |
1302 | Store a 0 in regs_live or allocnos_live for this register. */ | |
1303 | ||
1304 | static void | |
1305 | mark_reg_death (reg) | |
1306 | rtx reg; | |
1307 | { | |
1308 | register int regno = REGNO (reg); | |
1309 | ||
1310 | /* For pseudo reg, see if it has been assigned a hardware reg. */ | |
1311 | if (reg_renumber[regno] >= 0) | |
1312 | regno = reg_renumber[regno]; | |
1313 | ||
1314 | /* Either this is one of the max_allocno pseudo regs not allocated, | |
1315 | or it is a hardware reg. First handle the pseudo-regs. */ | |
1316 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1317 | { | |
1318 | if (reg_allocno[regno] >= 0) | |
1319 | CLEAR_ALLOCNO_LIVE (reg_allocno[regno]); | |
1320 | } | |
1321 | /* Handle hardware regs (and pseudos allocated to hard regs). */ | |
1322 | else if (! fixed_regs[regno]) | |
1323 | { | |
1324 | /* Pseudo regs already assigned hardware regs are treated | |
1325 | almost the same as explicit hardware regs. */ | |
1326 | register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
1327 | while (regno < last) | |
1328 | { | |
1329 | CLEAR_HARD_REG_BIT (hard_regs_live, regno); | |
1330 | regno++; | |
1331 | } | |
1332 | } | |
1333 | } | |
1334 | ||
1335 | /* Mark hard reg REGNO as currently live, assuming machine mode MODE | |
1336 | for the value stored in it. MODE determines how many consecutive | |
1337 | registers are actually in use. Do not record conflicts; | |
1338 | it is assumed that the caller will do that. */ | |
1339 | ||
1340 | static void | |
1341 | mark_reg_live_nc (regno, mode) | |
1342 | register int regno; | |
1343 | enum machine_mode mode; | |
1344 | { | |
1345 | register int last = regno + HARD_REGNO_NREGS (regno, mode); | |
1346 | while (regno < last) | |
1347 | { | |
1348 | SET_HARD_REG_BIT (hard_regs_live, regno); | |
1349 | regno++; | |
1350 | } | |
1351 | } | |
1352 | \f | |
1353 | /* Try to set a preference for an allocno to a hard register. | |
1354 | We are passed DEST and SRC which are the operands of a SET. It is known | |
1355 | that SRC is a register. If SRC or the first operand of SRC is a register, | |
1356 | try to set a preference. If one of the two is a hard register and the other | |
1357 | is a pseudo-register, mark the preference. | |
1358 | ||
1359 | Note that we are not as agressive as local-alloc in trying to tie a | |
1360 | pseudo-register to a hard register. */ | |
1361 | ||
1362 | static void | |
1363 | set_preference (dest, src) | |
1364 | rtx dest, src; | |
1365 | { | |
1366 | int src_regno, dest_regno; | |
1367 | /* Amount to add to the hard regno for SRC, or subtract from that for DEST, | |
1368 | to compensate for subregs in SRC or DEST. */ | |
1369 | int offset = 0; | |
1370 | int i; | |
1371 | int copy = 1; | |
1372 | ||
1373 | if (GET_RTX_FORMAT (GET_CODE (src))[0] == 'e') | |
1374 | src = XEXP (src, 0), copy = 0; | |
1375 | ||
1376 | /* Get the reg number for both SRC and DEST. | |
1377 | If neither is a reg, give up. */ | |
1378 | ||
1379 | if (GET_CODE (src) == REG) | |
1380 | src_regno = REGNO (src); | |
1381 | else if (GET_CODE (src) == SUBREG && GET_CODE (SUBREG_REG (src)) == REG) | |
1382 | { | |
1383 | src_regno = REGNO (SUBREG_REG (src)); | |
1384 | offset += SUBREG_WORD (src); | |
1385 | } | |
1386 | else | |
1387 | return; | |
1388 | ||
1389 | if (GET_CODE (dest) == REG) | |
1390 | dest_regno = REGNO (dest); | |
1391 | else if (GET_CODE (dest) == SUBREG && GET_CODE (SUBREG_REG (dest)) == REG) | |
1392 | { | |
1393 | dest_regno = REGNO (SUBREG_REG (dest)); | |
1394 | offset -= SUBREG_WORD (dest); | |
1395 | } | |
1396 | else | |
1397 | return; | |
1398 | ||
1399 | /* Convert either or both to hard reg numbers. */ | |
1400 | ||
1401 | if (reg_renumber[src_regno] >= 0) | |
1402 | src_regno = reg_renumber[src_regno]; | |
1403 | ||
1404 | if (reg_renumber[dest_regno] >= 0) | |
1405 | dest_regno = reg_renumber[dest_regno]; | |
1406 | ||
1407 | /* Now if one is a hard reg and the other is a global pseudo | |
1408 | then give the other a preference. */ | |
1409 | ||
1410 | if (dest_regno < FIRST_PSEUDO_REGISTER && src_regno >= FIRST_PSEUDO_REGISTER | |
1411 | && reg_allocno[src_regno] >= 0) | |
1412 | { | |
1413 | dest_regno -= offset; | |
1414 | if (dest_regno >= 0 && dest_regno < FIRST_PSEUDO_REGISTER) | |
1415 | { | |
1416 | if (copy) | |
1417 | SET_REGBIT (hard_reg_copy_preferences, | |
1418 | reg_allocno[src_regno], dest_regno); | |
1419 | ||
1420 | SET_REGBIT (hard_reg_preferences, | |
1421 | reg_allocno[src_regno], dest_regno); | |
1422 | for (i = dest_regno; | |
1423 | i < dest_regno + HARD_REGNO_NREGS (dest_regno, GET_MODE (dest)); | |
1424 | i++) | |
1425 | SET_REGBIT (hard_reg_full_preferences, reg_allocno[src_regno], i); | |
1426 | } | |
1427 | } | |
1428 | ||
1429 | if (src_regno < FIRST_PSEUDO_REGISTER && dest_regno >= FIRST_PSEUDO_REGISTER | |
1430 | && reg_allocno[dest_regno] >= 0) | |
1431 | { | |
1432 | src_regno += offset; | |
1433 | if (src_regno >= 0 && src_regno < FIRST_PSEUDO_REGISTER) | |
1434 | { | |
1435 | if (copy) | |
1436 | SET_REGBIT (hard_reg_copy_preferences, | |
1437 | reg_allocno[dest_regno], src_regno); | |
1438 | ||
1439 | SET_REGBIT (hard_reg_preferences, | |
1440 | reg_allocno[dest_regno], src_regno); | |
1441 | for (i = src_regno; | |
1442 | i < src_regno + HARD_REGNO_NREGS (src_regno, GET_MODE (src)); | |
1443 | i++) | |
1444 | SET_REGBIT (hard_reg_full_preferences, reg_allocno[dest_regno], i); | |
1445 | } | |
1446 | } | |
1447 | } | |
1448 | \f | |
1449 | /* Indicate that hard register number FROM was eliminated and replaced with | |
1450 | an offset from hard register number TO. The status of hard registers live | |
1451 | at the start of a basic block is updated by replacing a use of FROM with | |
1452 | a use of TO. */ | |
1453 | ||
1454 | void | |
1455 | mark_elimination (from, to) | |
1456 | int from, to; | |
1457 | { | |
1458 | int i; | |
1459 | ||
1460 | for (i = 0; i < n_basic_blocks; i++) | |
1461 | if ((basic_block_live_at_start[i][from / HOST_BITS_PER_INT] | |
1462 | & (1 << (from % HOST_BITS_PER_INT))) != 0) | |
1463 | { | |
1464 | basic_block_live_at_start[i][from / HOST_BITS_PER_INT] | |
1465 | &= ~ (1 << (from % HOST_BITS_PER_INT)); | |
1466 | basic_block_live_at_start[i][to / HOST_BITS_PER_INT] | |
1467 | |= (1 << (to % HOST_BITS_PER_INT)); | |
1468 | } | |
1469 | } | |
1470 | \f | |
1471 | /* Print debugging trace information if -greg switch is given, | |
1472 | showing the information on which the allocation decisions are based. */ | |
1473 | ||
1474 | static void | |
1475 | dump_conflicts (file) | |
1476 | FILE *file; | |
1477 | { | |
1478 | register int i; | |
1479 | register int has_preferences; | |
1480 | fprintf (file, ";; %d regs to allocate:", max_allocno); | |
1481 | for (i = 0; i < max_allocno; i++) | |
1482 | { | |
1483 | int j; | |
1484 | fprintf (file, " %d", allocno_reg[allocno_order[i]]); | |
1485 | for (j = 0; j < max_regno; j++) | |
1486 | if (reg_allocno[j] == allocno_order[i] | |
1487 | && j != allocno_reg[allocno_order[i]]) | |
1488 | fprintf (file, "+%d", j); | |
1489 | if (allocno_size[allocno_order[i]] != 1) | |
1490 | fprintf (file, " (%d)", allocno_size[allocno_order[i]]); | |
1491 | } | |
1492 | fprintf (file, "\n"); | |
1493 | ||
1494 | for (i = 0; i < max_allocno; i++) | |
1495 | { | |
1496 | register int j; | |
1497 | fprintf (file, ";; %d conflicts:", allocno_reg[i]); | |
1498 | for (j = 0; j < max_allocno; j++) | |
1499 | if (CONFLICTP (i, j) || CONFLICTP (j, i)) | |
1500 | fprintf (file, " %d", allocno_reg[j]); | |
1501 | for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) | |
1502 | if (TEST_HARD_REG_BIT (hard_reg_conflicts[i], j)) | |
1503 | fprintf (file, " %d", j); | |
1504 | fprintf (file, "\n"); | |
1505 | ||
1506 | has_preferences = 0; | |
1507 | for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) | |
1508 | if (TEST_HARD_REG_BIT (hard_reg_preferences[i], j)) | |
1509 | has_preferences = 1; | |
1510 | ||
1511 | if (! has_preferences) | |
1512 | continue; | |
1513 | fprintf (file, ";; %d preferences:", allocno_reg[i]); | |
1514 | for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) | |
1515 | if (TEST_HARD_REG_BIT (hard_reg_preferences[i], j)) | |
1516 | fprintf (file, " %d", j); | |
1517 | fprintf (file, "\n"); | |
1518 | } | |
1519 | fprintf (file, "\n"); | |
1520 | } | |
1521 | ||
1522 | void | |
1523 | dump_global_regs (file) | |
1524 | FILE *file; | |
1525 | { | |
1526 | register int i, j; | |
1527 | ||
1528 | fprintf (file, ";; Register dispositions:\n"); | |
1529 | for (i = FIRST_PSEUDO_REGISTER, j = 0; i < max_regno; i++) | |
1530 | if (reg_renumber[i] >= 0) | |
1531 | { | |
1532 | fprintf (file, "%d in %d ", i, reg_renumber[i]); | |
1533 | if (++j % 6 == 0) | |
1534 | fprintf (file, "\n"); | |
1535 | } | |
1536 | ||
1537 | fprintf (file, "\n\n;; Hard regs used: "); | |
1538 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
1539 | if (regs_ever_live[i]) | |
1540 | fprintf (file, " %d", i); | |
1541 | fprintf (file, "\n\n"); | |
1542 | } |