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38398762 | 1 | /* Allocate registers for pseudo-registers that span basic blocks. |
1313ec9d | 2 | Copyright (C) 1987, 88, 91, 94, 96, 1997 Free Software Foundation, Inc. |
38398762 RK |
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 | |
a35311b0 RK |
18 | the Free Software Foundation, 59 Temple Place - Suite 330, |
19 | Boston, MA 02111-1307, USA. */ | |
38398762 RK |
20 | |
21 | ||
38398762 | 22 | #include "config.h" |
670ee920 | 23 | #include "system.h" |
ccd043a9 | 24 | |
f6781658 L |
25 | #include "machmode.h" |
26 | #include "hard-reg-set.h" | |
38398762 RK |
27 | #include "rtl.h" |
28 | #include "flags.h" | |
29 | #include "basic-block.h" | |
38398762 RK |
30 | #include "regs.h" |
31 | #include "insn-config.h" | |
cad6f7d0 | 32 | #include "reload.h" |
38398762 | 33 | #include "output.h" |
2e107e9e | 34 | #include "toplev.h" |
38398762 RK |
35 | |
36 | /* This pass of the compiler performs global register allocation. | |
37 | It assigns hard register numbers to all the pseudo registers | |
38 | that were not handled in local_alloc. Assignments are recorded | |
39 | in the vector reg_renumber, not by changing the rtl code. | |
40 | (Such changes are made by final). The entry point is | |
41 | the function global_alloc. | |
42 | ||
43 | After allocation is complete, the reload pass is run as a subroutine | |
44 | of this pass, so that when a pseudo reg loses its hard reg due to | |
45 | spilling it is possible to make a second attempt to find a hard | |
46 | reg for it. The reload pass is independent in other respects | |
47 | and it is run even when stupid register allocation is in use. | |
48 | ||
a300b8d9 JW |
49 | 1. Assign allocation-numbers (allocnos) to the pseudo-registers |
50 | still needing allocations and to the pseudo-registers currently | |
51 | allocated by local-alloc which may be spilled by reload. | |
38398762 RK |
52 | Set up tables reg_allocno and allocno_reg to map |
53 | reg numbers to allocnos and vice versa. | |
54 | max_allocno gets the number of allocnos in use. | |
55 | ||
56 | 2. Allocate a max_allocno by max_allocno conflict bit matrix and clear it. | |
57 | Allocate a max_allocno by FIRST_PSEUDO_REGISTER conflict matrix | |
58 | for conflicts between allocnos and explicit hard register use | |
59 | (which includes use of pseudo-registers allocated by local_alloc). | |
60 | ||
a300b8d9 | 61 | 3. For each basic block |
38398762 | 62 | walk forward through the block, recording which |
a300b8d9 JW |
63 | pseudo-registers and which hardware registers are live. |
64 | Build the conflict matrix between the pseudo-registers | |
65 | and another of pseudo-registers versus hardware registers. | |
38398762 | 66 | Also record the preferred hardware registers |
a300b8d9 | 67 | for each pseudo-register. |
38398762 RK |
68 | |
69 | 4. Sort a table of the allocnos into order of | |
70 | desirability of the variables. | |
71 | ||
72 | 5. Allocate the variables in that order; each if possible into | |
73 | a preferred register, else into another register. */ | |
74 | \f | |
a300b8d9 | 75 | /* Number of pseudo-registers which are candidates for allocation. */ |
38398762 RK |
76 | |
77 | static int max_allocno; | |
78 | ||
79 | /* Indexed by (pseudo) reg number, gives the allocno, or -1 | |
a300b8d9 | 80 | for pseudo registers which are not to be allocated. */ |
38398762 | 81 | |
f15ebf65 | 82 | static int *reg_allocno; |
38398762 RK |
83 | |
84 | /* Indexed by allocno, gives the reg number. */ | |
85 | ||
86 | static int *allocno_reg; | |
87 | ||
88 | /* A vector of the integers from 0 to max_allocno-1, | |
89 | sorted in the order of first-to-be-allocated first. */ | |
90 | ||
91 | static int *allocno_order; | |
92 | ||
93 | /* Indexed by an allocno, gives the number of consecutive | |
94 | hard registers needed by that pseudo reg. */ | |
95 | ||
96 | static int *allocno_size; | |
97 | ||
98 | /* Indexed by (pseudo) reg number, gives the number of another | |
6dc42e49 | 99 | lower-numbered pseudo reg which can share a hard reg with this pseudo |
38398762 RK |
100 | *even if the two pseudos would otherwise appear to conflict*. */ |
101 | ||
102 | static int *reg_may_share; | |
103 | ||
b1ec3c92 CH |
104 | /* Define the number of bits in each element of `conflicts' and what |
105 | type that element has. We use the largest integer format on the | |
106 | host machine. */ | |
107 | ||
108 | #define INT_BITS HOST_BITS_PER_WIDE_INT | |
109 | #define INT_TYPE HOST_WIDE_INT | |
110 | ||
38398762 RK |
111 | /* max_allocno by max_allocno array of bits, |
112 | recording whether two allocno's conflict (can't go in the same | |
113 | hardware register). | |
114 | ||
115 | `conflicts' is not symmetric; a conflict between allocno's i and j | |
116 | is recorded either in element i,j or in element j,i. */ | |
117 | ||
b1ec3c92 | 118 | static INT_TYPE *conflicts; |
38398762 RK |
119 | |
120 | /* Number of ints require to hold max_allocno bits. | |
121 | This is the length of a row in `conflicts'. */ | |
122 | ||
123 | static int allocno_row_words; | |
124 | ||
125 | /* Two macros to test or store 1 in an element of `conflicts'. */ | |
126 | ||
127 | #define CONFLICTP(I, J) \ | |
128 | (conflicts[(I) * allocno_row_words + (J) / INT_BITS] \ | |
b1ec3c92 | 129 | & ((INT_TYPE) 1 << ((J) % INT_BITS))) |
38398762 RK |
130 | |
131 | #define SET_CONFLICT(I, J) \ | |
132 | (conflicts[(I) * allocno_row_words + (J) / INT_BITS] \ | |
b1ec3c92 | 133 | |= ((INT_TYPE) 1 << ((J) % INT_BITS))) |
38398762 RK |
134 | |
135 | /* Set of hard regs currently live (during scan of all insns). */ | |
136 | ||
137 | static HARD_REG_SET hard_regs_live; | |
138 | ||
139 | /* Indexed by N, set of hard regs conflicting with allocno N. */ | |
140 | ||
141 | static HARD_REG_SET *hard_reg_conflicts; | |
142 | ||
143 | /* Indexed by N, set of hard regs preferred by allocno N. | |
144 | This is used to make allocnos go into regs that are copied to or from them, | |
145 | when possible, to reduce register shuffling. */ | |
146 | ||
147 | static HARD_REG_SET *hard_reg_preferences; | |
148 | ||
149 | /* Similar, but just counts register preferences made in simple copy | |
150 | operations, rather than arithmetic. These are given priority because | |
151 | we can always eliminate an insn by using these, but using a register | |
152 | in the above list won't always eliminate an insn. */ | |
153 | ||
154 | static HARD_REG_SET *hard_reg_copy_preferences; | |
155 | ||
156 | /* Similar to hard_reg_preferences, but includes bits for subsequent | |
157 | registers when an allocno is multi-word. The above variable is used for | |
158 | allocation while this is used to build reg_someone_prefers, below. */ | |
159 | ||
160 | static HARD_REG_SET *hard_reg_full_preferences; | |
161 | ||
162 | /* Indexed by N, set of hard registers that some later allocno has a | |
163 | preference for. */ | |
164 | ||
165 | static HARD_REG_SET *regs_someone_prefers; | |
166 | ||
167 | /* Set of registers that global-alloc isn't supposed to use. */ | |
168 | ||
169 | static HARD_REG_SET no_global_alloc_regs; | |
170 | ||
171 | /* Set of registers used so far. */ | |
172 | ||
173 | static HARD_REG_SET regs_used_so_far; | |
174 | ||
175 | /* Number of calls crossed by each allocno. */ | |
176 | ||
177 | static int *allocno_calls_crossed; | |
178 | ||
179 | /* Number of refs (weighted) to each allocno. */ | |
180 | ||
181 | static int *allocno_n_refs; | |
182 | ||
183 | /* Guess at live length of each allocno. | |
184 | This is actually the max of the live lengths of the regs. */ | |
185 | ||
186 | static int *allocno_live_length; | |
187 | ||
1d56e983 RS |
188 | /* Number of refs (weighted) to each hard reg, as used by local alloc. |
189 | It is zero for a reg that contains global pseudos or is explicitly used. */ | |
190 | ||
191 | static int local_reg_n_refs[FIRST_PSEUDO_REGISTER]; | |
192 | ||
193 | /* Guess at live length of each hard reg, as used by local alloc. | |
194 | This is actually the sum of the live lengths of the specific regs. */ | |
195 | ||
196 | static int local_reg_live_length[FIRST_PSEUDO_REGISTER]; | |
197 | ||
38398762 RK |
198 | /* Test a bit in TABLE, a vector of HARD_REG_SETs, |
199 | for vector element I, and hard register number J. */ | |
200 | ||
201 | #define REGBITP(TABLE, I, J) TEST_HARD_REG_BIT (TABLE[I], J) | |
202 | ||
203 | /* Set to 1 a bit in a vector of HARD_REG_SETs. Works like REGBITP. */ | |
204 | ||
205 | #define SET_REGBIT(TABLE, I, J) SET_HARD_REG_BIT (TABLE[I], J) | |
206 | ||
207 | /* Bit mask for allocnos live at current point in the scan. */ | |
208 | ||
b1ec3c92 | 209 | static INT_TYPE *allocnos_live; |
38398762 RK |
210 | |
211 | /* Test, set or clear bit number I in allocnos_live, | |
212 | a bit vector indexed by allocno. */ | |
213 | ||
214 | #define ALLOCNO_LIVE_P(I) \ | |
b1ec3c92 | 215 | (allocnos_live[(I) / INT_BITS] & ((INT_TYPE) 1 << ((I) % INT_BITS))) |
38398762 RK |
216 | |
217 | #define SET_ALLOCNO_LIVE(I) \ | |
b1ec3c92 | 218 | (allocnos_live[(I) / INT_BITS] |= ((INT_TYPE) 1 << ((I) % INT_BITS))) |
38398762 RK |
219 | |
220 | #define CLEAR_ALLOCNO_LIVE(I) \ | |
b1ec3c92 | 221 | (allocnos_live[(I) / INT_BITS] &= ~((INT_TYPE) 1 << ((I) % INT_BITS))) |
38398762 RK |
222 | |
223 | /* This is turned off because it doesn't work right for DImode. | |
224 | (And it is only used for DImode, so the other cases are worthless.) | |
225 | The problem is that it isn't true that there is NO possibility of conflict; | |
226 | only that there is no conflict if the two pseudos get the exact same regs. | |
227 | If they were allocated with a partial overlap, there would be a conflict. | |
228 | We can't safely turn off the conflict unless we have another way to | |
229 | prevent the partial overlap. | |
230 | ||
231 | Idea: change hard_reg_conflicts so that instead of recording which | |
232 | hard regs the allocno may not overlap, it records where the allocno | |
233 | may not start. Change both where it is used and where it is updated. | |
234 | Then there is a way to record that (reg:DI 108) may start at 10 | |
235 | but not at 9 or 11. There is still the question of how to record | |
236 | this semi-conflict between two pseudos. */ | |
237 | #if 0 | |
238 | /* Reg pairs for which conflict after the current insn | |
239 | is inhibited by a REG_NO_CONFLICT note. | |
240 | If the table gets full, we ignore any other notes--that is conservative. */ | |
241 | #define NUM_NO_CONFLICT_PAIRS 4 | |
242 | /* Number of pairs in use in this insn. */ | |
243 | int n_no_conflict_pairs; | |
244 | static struct { int allocno1, allocno2;} | |
245 | no_conflict_pairs[NUM_NO_CONFLICT_PAIRS]; | |
246 | #endif /* 0 */ | |
247 | ||
248 | /* Record all regs that are set in any one insn. | |
249 | Communication from mark_reg_{store,clobber} and global_conflicts. */ | |
250 | ||
251 | static rtx *regs_set; | |
252 | static int n_regs_set; | |
253 | ||
daf55ac6 | 254 | /* All registers that can be eliminated. */ |
38398762 RK |
255 | |
256 | static HARD_REG_SET eliminable_regset; | |
257 | ||
daa6f17d | 258 | static int allocno_compare PROTO((const GENERIC_PTR, const GENERIC_PTR)); |
82c68a78 RK |
259 | static void global_conflicts PROTO((void)); |
260 | static void expand_preferences PROTO((void)); | |
261 | static void prune_preferences PROTO((void)); | |
262 | static void find_reg PROTO((int, HARD_REG_SET, int, int, int)); | |
263 | static void record_one_conflict PROTO((int)); | |
264 | static void record_conflicts PROTO((short *, int)); | |
265 | static void mark_reg_store PROTO((rtx, rtx)); | |
266 | static void mark_reg_clobber PROTO((rtx, rtx)); | |
267 | static void mark_reg_conflicts PROTO((rtx)); | |
268 | static void mark_reg_death PROTO((rtx)); | |
269 | static void mark_reg_live_nc PROTO((int, enum machine_mode)); | |
270 | static void set_preference PROTO((rtx, rtx)); | |
271 | static void dump_conflicts PROTO((FILE *)); | |
cad6f7d0 BS |
272 | static void reg_becomes_live PROTO((rtx, rtx)); |
273 | static void reg_dies PROTO((int, enum machine_mode)); | |
274 | static void build_insn_chain PROTO((rtx)); | |
38398762 RK |
275 | \f |
276 | /* Perform allocation of pseudo-registers not allocated by local_alloc. | |
277 | FILE is a file to output debugging information on, | |
ab40ad2b | 278 | or zero if such output is not desired. |
38398762 | 279 | |
ab40ad2b RS |
280 | Return value is nonzero if reload failed |
281 | and we must not do any more for this function. */ | |
282 | ||
283 | int | |
38398762 RK |
284 | global_alloc (file) |
285 | FILE *file; | |
286 | { | |
8c316ae2 | 287 | int retval; |
38398762 RK |
288 | #ifdef ELIMINABLE_REGS |
289 | static struct {int from, to; } eliminables[] = ELIMINABLE_REGS; | |
290 | #endif | |
daf55ac6 RK |
291 | int need_fp |
292 | = (! flag_omit_frame_pointer | |
293 | #ifdef EXIT_IGNORE_STACK | |
294 | || (current_function_calls_alloca && EXIT_IGNORE_STACK) | |
295 | #endif | |
296 | || FRAME_POINTER_REQUIRED); | |
297 | ||
f8344bea | 298 | register size_t i; |
38398762 RK |
299 | rtx x; |
300 | ||
301 | max_allocno = 0; | |
302 | ||
303 | /* A machine may have certain hard registers that | |
304 | are safe to use only within a basic block. */ | |
305 | ||
306 | CLEAR_HARD_REG_SET (no_global_alloc_regs); | |
307 | #ifdef OVERLAPPING_REGNO_P | |
308 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
309 | if (OVERLAPPING_REGNO_P (i)) | |
310 | SET_HARD_REG_BIT (no_global_alloc_regs, i); | |
311 | #endif | |
312 | ||
313 | /* Build the regset of all eliminable registers and show we can't use those | |
314 | that we already know won't be eliminated. */ | |
315 | #ifdef ELIMINABLE_REGS | |
316 | for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++) | |
317 | { | |
318 | SET_HARD_REG_BIT (eliminable_regset, eliminables[i].from); | |
319 | ||
320 | if (! CAN_ELIMINATE (eliminables[i].from, eliminables[i].to) | |
daf55ac6 | 321 | || (eliminables[i].to == STACK_POINTER_REGNUM && need_fp)) |
38398762 RK |
322 | SET_HARD_REG_BIT (no_global_alloc_regs, eliminables[i].from); |
323 | } | |
7b0957a7 | 324 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
daf55ac6 RK |
325 | SET_HARD_REG_BIT (eliminable_regset, HARD_FRAME_POINTER_REGNUM); |
326 | if (need_fp) | |
7b0957a7 DE |
327 | SET_HARD_REG_BIT (no_global_alloc_regs, HARD_FRAME_POINTER_REGNUM); |
328 | #endif | |
daf55ac6 | 329 | |
38398762 RK |
330 | #else |
331 | SET_HARD_REG_BIT (eliminable_regset, FRAME_POINTER_REGNUM); | |
daf55ac6 | 332 | if (need_fp) |
38398762 RK |
333 | SET_HARD_REG_BIT (no_global_alloc_regs, FRAME_POINTER_REGNUM); |
334 | #endif | |
335 | ||
336 | /* Track which registers have already been used. Start with registers | |
337 | explicitly in the rtl, then registers allocated by local register | |
b4b4db94 | 338 | allocation. */ |
38398762 RK |
339 | |
340 | CLEAR_HARD_REG_SET (regs_used_so_far); | |
b4b4db94 RS |
341 | #ifdef LEAF_REGISTERS |
342 | /* If we are doing the leaf function optimization, and this is a leaf | |
343 | function, it means that the registers that take work to save are those | |
344 | that need a register window. So prefer the ones that can be used in | |
345 | a leaf function. */ | |
346 | { | |
347 | char *cheap_regs; | |
348 | static char leaf_regs[] = LEAF_REGISTERS; | |
349 | ||
350 | if (only_leaf_regs_used () && leaf_function_p ()) | |
351 | cheap_regs = leaf_regs; | |
352 | else | |
353 | cheap_regs = call_used_regs; | |
354 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
355 | if (regs_ever_live[i] || cheap_regs[i]) | |
356 | SET_HARD_REG_BIT (regs_used_so_far, i); | |
357 | } | |
358 | #else | |
359 | /* We consider registers that do not have to be saved over calls as if | |
360 | they were already used since there is no cost in using them. */ | |
38398762 RK |
361 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
362 | if (regs_ever_live[i] || call_used_regs[i]) | |
363 | SET_HARD_REG_BIT (regs_used_so_far, i); | |
b4b4db94 | 364 | #endif |
38398762 RK |
365 | |
366 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) | |
367 | if (reg_renumber[i] >= 0) | |
368 | SET_HARD_REG_BIT (regs_used_so_far, reg_renumber[i]); | |
369 | ||
370 | /* Establish mappings from register number to allocation number | |
371 | and vice versa. In the process, count the allocnos. */ | |
372 | ||
373 | reg_allocno = (int *) alloca (max_regno * sizeof (int)); | |
374 | ||
375 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
376 | reg_allocno[i] = -1; | |
377 | ||
378 | /* Initialize the shared-hard-reg mapping | |
379 | from the list of pairs that may share. */ | |
380 | reg_may_share = (int *) alloca (max_regno * sizeof (int)); | |
4c9a05bc | 381 | bzero ((char *) reg_may_share, max_regno * sizeof (int)); |
38398762 RK |
382 | for (x = regs_may_share; x; x = XEXP (XEXP (x, 1), 1)) |
383 | { | |
384 | int r1 = REGNO (XEXP (x, 0)); | |
385 | int r2 = REGNO (XEXP (XEXP (x, 1), 0)); | |
386 | if (r1 > r2) | |
387 | reg_may_share[r1] = r2; | |
388 | else | |
389 | reg_may_share[r2] = r1; | |
390 | } | |
391 | ||
392 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) | |
393 | /* Note that reg_live_length[i] < 0 indicates a "constant" reg | |
394 | that we are supposed to refrain from putting in a hard reg. | |
395 | -2 means do make an allocno but don't allocate it. */ | |
a300b8d9 | 396 | if (REG_N_REFS (i) != 0 && REG_LIVE_LENGTH (i) != -1 |
38398762 RK |
397 | /* Don't allocate pseudos that cross calls, |
398 | if this function receives a nonlocal goto. */ | |
399 | && (! current_function_has_nonlocal_label | |
b1f21e0a | 400 | || REG_N_CALLS_CROSSED (i) == 0)) |
38398762 | 401 | { |
a300b8d9 | 402 | if (reg_renumber[i] < 0 && reg_may_share[i] && reg_allocno[reg_may_share[i]] >= 0) |
38398762 RK |
403 | reg_allocno[i] = reg_allocno[reg_may_share[i]]; |
404 | else | |
405 | reg_allocno[i] = max_allocno++; | |
b1f21e0a | 406 | if (REG_LIVE_LENGTH (i) == 0) |
38398762 RK |
407 | abort (); |
408 | } | |
409 | else | |
410 | reg_allocno[i] = -1; | |
411 | ||
412 | allocno_reg = (int *) alloca (max_allocno * sizeof (int)); | |
413 | allocno_size = (int *) alloca (max_allocno * sizeof (int)); | |
414 | allocno_calls_crossed = (int *) alloca (max_allocno * sizeof (int)); | |
415 | allocno_n_refs = (int *) alloca (max_allocno * sizeof (int)); | |
416 | allocno_live_length = (int *) alloca (max_allocno * sizeof (int)); | |
4c9a05bc RK |
417 | bzero ((char *) allocno_size, max_allocno * sizeof (int)); |
418 | bzero ((char *) allocno_calls_crossed, max_allocno * sizeof (int)); | |
419 | bzero ((char *) allocno_n_refs, max_allocno * sizeof (int)); | |
420 | bzero ((char *) allocno_live_length, max_allocno * sizeof (int)); | |
38398762 RK |
421 | |
422 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) | |
423 | if (reg_allocno[i] >= 0) | |
424 | { | |
425 | int allocno = reg_allocno[i]; | |
426 | allocno_reg[allocno] = i; | |
427 | allocno_size[allocno] = PSEUDO_REGNO_SIZE (i); | |
b1f21e0a MM |
428 | allocno_calls_crossed[allocno] += REG_N_CALLS_CROSSED (i); |
429 | allocno_n_refs[allocno] += REG_N_REFS (i); | |
430 | if (allocno_live_length[allocno] < REG_LIVE_LENGTH (i)) | |
431 | allocno_live_length[allocno] = REG_LIVE_LENGTH (i); | |
38398762 RK |
432 | } |
433 | ||
1d56e983 RS |
434 | /* Calculate amount of usage of each hard reg by pseudos |
435 | allocated by local-alloc. This is to see if we want to | |
436 | override it. */ | |
4c9a05bc RK |
437 | bzero ((char *) local_reg_live_length, sizeof local_reg_live_length); |
438 | bzero ((char *) local_reg_n_refs, sizeof local_reg_n_refs); | |
1d56e983 | 439 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) |
a300b8d9 | 440 | if (reg_renumber[i] >= 0) |
1d56e983 | 441 | { |
34e56753 RS |
442 | int regno = reg_renumber[i]; |
443 | int endregno = regno + HARD_REGNO_NREGS (regno, PSEUDO_REGNO_MODE (i)); | |
444 | int j; | |
445 | ||
446 | for (j = regno; j < endregno; j++) | |
447 | { | |
b1f21e0a MM |
448 | local_reg_n_refs[j] += REG_N_REFS (i); |
449 | local_reg_live_length[j] += REG_LIVE_LENGTH (i); | |
34e56753 | 450 | } |
1d56e983 | 451 | } |
34e56753 | 452 | |
1d56e983 RS |
453 | /* We can't override local-alloc for a reg used not just by local-alloc. */ |
454 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
455 | if (regs_ever_live[i]) | |
456 | local_reg_n_refs[i] = 0; | |
0dfa4517 | 457 | |
38398762 RK |
458 | /* Allocate the space for the conflict and preference tables and |
459 | initialize them. */ | |
460 | ||
461 | hard_reg_conflicts | |
462 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); | |
4c9a05bc | 463 | bzero ((char *) hard_reg_conflicts, max_allocno * sizeof (HARD_REG_SET)); |
38398762 RK |
464 | |
465 | hard_reg_preferences | |
466 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); | |
4c9a05bc | 467 | bzero ((char *) hard_reg_preferences, max_allocno * sizeof (HARD_REG_SET)); |
38398762 RK |
468 | |
469 | hard_reg_copy_preferences | |
470 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); | |
4c9a05bc RK |
471 | bzero ((char *) hard_reg_copy_preferences, |
472 | max_allocno * sizeof (HARD_REG_SET)); | |
38398762 RK |
473 | |
474 | hard_reg_full_preferences | |
475 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); | |
4c9a05bc RK |
476 | bzero ((char *) hard_reg_full_preferences, |
477 | max_allocno * sizeof (HARD_REG_SET)); | |
38398762 RK |
478 | |
479 | regs_someone_prefers | |
480 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); | |
4c9a05bc | 481 | bzero ((char *) regs_someone_prefers, max_allocno * sizeof (HARD_REG_SET)); |
38398762 RK |
482 | |
483 | allocno_row_words = (max_allocno + INT_BITS - 1) / INT_BITS; | |
484 | ||
ba3b3878 BK |
485 | /* We used to use alloca here, but the size of what it would try to |
486 | allocate would occasionally cause it to exceed the stack limit and | |
487 | cause unpredictable core dumps. Some examples were > 2Mb in size. */ | |
488 | conflicts = (INT_TYPE *) xmalloc (max_allocno * allocno_row_words | |
489 | * sizeof (INT_TYPE)); | |
4c9a05bc RK |
490 | bzero ((char *) conflicts, |
491 | max_allocno * allocno_row_words * sizeof (INT_TYPE)); | |
38398762 | 492 | |
b1ec3c92 | 493 | allocnos_live = (INT_TYPE *) alloca (allocno_row_words * sizeof (INT_TYPE)); |
38398762 RK |
494 | |
495 | /* If there is work to be done (at least one reg to allocate), | |
496 | perform global conflict analysis and allocate the regs. */ | |
497 | ||
498 | if (max_allocno > 0) | |
499 | { | |
500 | /* Scan all the insns and compute the conflicts among allocnos | |
501 | and between allocnos and hard regs. */ | |
502 | ||
503 | global_conflicts (); | |
504 | ||
505 | /* Eliminate conflicts between pseudos and eliminable registers. If | |
506 | the register is not eliminated, the pseudo won't really be able to | |
507 | live in the eliminable register, so the conflict doesn't matter. | |
508 | If we do eliminate the register, the conflict will no longer exist. | |
1d56e983 RS |
509 | So in either case, we can ignore the conflict. Likewise for |
510 | preferences. */ | |
38398762 RK |
511 | |
512 | for (i = 0; i < max_allocno; i++) | |
1d56e983 RS |
513 | { |
514 | AND_COMPL_HARD_REG_SET (hard_reg_conflicts[i], eliminable_regset); | |
515 | AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[i], | |
516 | eliminable_regset); | |
517 | AND_COMPL_HARD_REG_SET (hard_reg_preferences[i], eliminable_regset); | |
518 | } | |
38398762 RK |
519 | |
520 | /* Try to expand the preferences by merging them between allocnos. */ | |
521 | ||
522 | expand_preferences (); | |
523 | ||
524 | /* Determine the order to allocate the remaining pseudo registers. */ | |
525 | ||
526 | allocno_order = (int *) alloca (max_allocno * sizeof (int)); | |
527 | for (i = 0; i < max_allocno; i++) | |
528 | allocno_order[i] = i; | |
529 | ||
530 | /* Default the size to 1, since allocno_compare uses it to divide by. | |
531 | Also convert allocno_live_length of zero to -1. A length of zero | |
532 | can occur when all the registers for that allocno have reg_live_length | |
533 | equal to -2. In this case, we want to make an allocno, but not | |
534 | allocate it. So avoid the divide-by-zero and set it to a low | |
535 | priority. */ | |
536 | ||
537 | for (i = 0; i < max_allocno; i++) | |
538 | { | |
539 | if (allocno_size[i] == 0) | |
540 | allocno_size[i] = 1; | |
541 | if (allocno_live_length[i] == 0) | |
542 | allocno_live_length[i] = -1; | |
543 | } | |
544 | ||
545 | qsort (allocno_order, max_allocno, sizeof (int), allocno_compare); | |
546 | ||
547 | prune_preferences (); | |
548 | ||
549 | if (file) | |
550 | dump_conflicts (file); | |
551 | ||
552 | /* Try allocating them, one by one, in that order, | |
553 | except for parameters marked with reg_live_length[regno] == -2. */ | |
554 | ||
555 | for (i = 0; i < max_allocno; i++) | |
a300b8d9 JW |
556 | if (reg_renumber[allocno_reg[allocno_order[i]]] < 0 |
557 | && REG_LIVE_LENGTH (allocno_reg[allocno_order[i]]) >= 0) | |
38398762 RK |
558 | { |
559 | /* If we have more than one register class, | |
560 | first try allocating in the class that is cheapest | |
561 | for this pseudo-reg. If that fails, try any reg. */ | |
562 | if (N_REG_CLASSES > 1) | |
563 | { | |
ea8693a4 | 564 | find_reg (allocno_order[i], 0, 0, 0, 0); |
38398762 RK |
565 | if (reg_renumber[allocno_reg[allocno_order[i]]] >= 0) |
566 | continue; | |
567 | } | |
b1ec3c92 | 568 | if (reg_alternate_class (allocno_reg[allocno_order[i]]) != NO_REGS) |
ea8693a4 | 569 | find_reg (allocno_order[i], 0, 1, 0, 0); |
38398762 RK |
570 | } |
571 | } | |
572 | ||
573 | /* Do the reloads now while the allocno data still exist, so that we can | |
574 | try to assign new hard regs to any pseudo regs that are spilled. */ | |
575 | ||
7e860cf7 RS |
576 | #if 0 /* We need to eliminate regs even if there is no rtl code, |
577 | for the sake of debugging information. */ | |
38398762 | 578 | if (n_basic_blocks > 0) |
7e860cf7 | 579 | #endif |
cad6f7d0 BS |
580 | { |
581 | build_insn_chain (get_insns ()); | |
582 | retval = reload (get_insns (), 1, file); | |
583 | } | |
8c316ae2 JL |
584 | |
585 | free (conflicts); | |
586 | return retval; | |
38398762 RK |
587 | } |
588 | ||
589 | /* Sort predicate for ordering the allocnos. | |
590 | Returns -1 (1) if *v1 should be allocated before (after) *v2. */ | |
591 | ||
592 | static int | |
daa6f17d RK |
593 | allocno_compare (v1p, v2p) |
594 | const GENERIC_PTR v1p; | |
595 | const GENERIC_PTR v2p; | |
38398762 | 596 | { |
daa6f17d | 597 | int v1 = *(int *)v1p, v2 = *(int *)v2p; |
38398762 RK |
598 | /* Note that the quotient will never be bigger than |
599 | the value of floor_log2 times the maximum number of | |
600 | times a register can occur in one insn (surely less than 100). | |
601 | Multiplying this by 10000 can't overflow. */ | |
602 | register int pri1 | |
daa6f17d RK |
603 | = (((double) (floor_log2 (allocno_n_refs[v1]) * allocno_n_refs[v1]) |
604 | / allocno_live_length[v1]) | |
605 | * 10000 * allocno_size[v1]); | |
38398762 | 606 | register int pri2 |
daa6f17d RK |
607 | = (((double) (floor_log2 (allocno_n_refs[v2]) * allocno_n_refs[v2]) |
608 | / allocno_live_length[v2]) | |
609 | * 10000 * allocno_size[v2]); | |
38398762 RK |
610 | if (pri2 - pri1) |
611 | return pri2 - pri1; | |
612 | ||
613 | /* If regs are equally good, sort by allocno, | |
614 | so that the results of qsort leave nothing to chance. */ | |
daa6f17d | 615 | return v1 - v2; |
38398762 RK |
616 | } |
617 | \f | |
618 | /* Scan the rtl code and record all conflicts and register preferences in the | |
619 | conflict matrices and preference tables. */ | |
620 | ||
621 | static void | |
622 | global_conflicts () | |
623 | { | |
624 | register int b, i; | |
625 | register rtx insn; | |
626 | short *block_start_allocnos; | |
627 | ||
628 | /* Make a vector that mark_reg_{store,clobber} will store in. */ | |
629 | regs_set = (rtx *) alloca (max_parallel * sizeof (rtx) * 2); | |
630 | ||
631 | block_start_allocnos = (short *) alloca (max_allocno * sizeof (short)); | |
632 | ||
633 | for (b = 0; b < n_basic_blocks; b++) | |
634 | { | |
4c9a05bc | 635 | bzero ((char *) allocnos_live, allocno_row_words * sizeof (INT_TYPE)); |
38398762 RK |
636 | |
637 | /* Initialize table of registers currently live | |
638 | to the state at the beginning of this basic block. | |
639 | This also marks the conflicts among them. | |
640 | ||
641 | For pseudo-regs, there is only one bit for each one | |
642 | no matter how many hard regs it occupies. | |
643 | This is ok; we know the size from PSEUDO_REGNO_SIZE. | |
644 | For explicit hard regs, we cannot know the size that way | |
645 | since one hard reg can be used with various sizes. | |
646 | Therefore, we must require that all the hard regs | |
647 | implicitly live as part of a multi-word hard reg | |
648 | are explicitly marked in basic_block_live_at_start. */ | |
649 | ||
650 | { | |
38398762 RK |
651 | register regset old = basic_block_live_at_start[b]; |
652 | int ax = 0; | |
653 | ||
916b1701 | 654 | REG_SET_TO_HARD_REG_SET (hard_regs_live, old); |
1313ec9d | 655 | EXECUTE_IF_SET_IN_REG_SET (old, FIRST_PSEUDO_REGISTER, i, |
916b1701 MM |
656 | { |
657 | register int a = reg_allocno[i]; | |
658 | if (a >= 0) | |
659 | { | |
660 | SET_ALLOCNO_LIVE (a); | |
661 | block_start_allocnos[ax++] = a; | |
662 | } | |
663 | else if ((a = reg_renumber[i]) >= 0) | |
1313ec9d RK |
664 | mark_reg_live_nc |
665 | (a, PSEUDO_REGNO_MODE (i)); | |
916b1701 | 666 | }); |
38398762 RK |
667 | |
668 | /* Record that each allocno now live conflicts with each other | |
669 | allocno now live, and with each hard reg now live. */ | |
670 | ||
671 | record_conflicts (block_start_allocnos, ax); | |
4d1d8045 BS |
672 | |
673 | #ifdef STACK_REGS | |
674 | /* Pseudos can't go in stack regs at the start of a basic block | |
675 | that can be reached through a computed goto, since reg-stack | |
676 | can't handle computed gotos. */ | |
677 | if (basic_block_computed_jump_target[b]) | |
678 | for (ax = FIRST_STACK_REG; ax <= LAST_STACK_REG; ax++) | |
679 | record_one_conflict (ax); | |
680 | #endif | |
38398762 RK |
681 | } |
682 | ||
683 | insn = basic_block_head[b]; | |
684 | ||
685 | /* Scan the code of this basic block, noting which allocnos | |
686 | and hard regs are born or die. When one is born, | |
687 | record a conflict with all others currently live. */ | |
688 | ||
689 | while (1) | |
690 | { | |
691 | register RTX_CODE code = GET_CODE (insn); | |
692 | register rtx link; | |
693 | ||
694 | /* Make regs_set an empty set. */ | |
695 | ||
696 | n_regs_set = 0; | |
697 | ||
698 | if (code == INSN || code == CALL_INSN || code == JUMP_INSN) | |
699 | { | |
38398762 RK |
700 | |
701 | #if 0 | |
2049526b | 702 | int i = 0; |
38398762 RK |
703 | for (link = REG_NOTES (insn); |
704 | link && i < NUM_NO_CONFLICT_PAIRS; | |
705 | link = XEXP (link, 1)) | |
706 | if (REG_NOTE_KIND (link) == REG_NO_CONFLICT) | |
707 | { | |
708 | no_conflict_pairs[i].allocno1 | |
709 | = reg_allocno[REGNO (SET_DEST (PATTERN (insn)))]; | |
710 | no_conflict_pairs[i].allocno2 | |
711 | = reg_allocno[REGNO (XEXP (link, 0))]; | |
712 | i++; | |
713 | } | |
714 | #endif /* 0 */ | |
715 | ||
716 | /* Mark any registers clobbered by INSN as live, | |
717 | so they conflict with the inputs. */ | |
718 | ||
719 | note_stores (PATTERN (insn), mark_reg_clobber); | |
720 | ||
721 | /* Mark any registers dead after INSN as dead now. */ | |
722 | ||
723 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
724 | if (REG_NOTE_KIND (link) == REG_DEAD) | |
725 | mark_reg_death (XEXP (link, 0)); | |
726 | ||
727 | /* Mark any registers set in INSN as live, | |
728 | and mark them as conflicting with all other live regs. | |
729 | Clobbers are processed again, so they conflict with | |
730 | the registers that are set. */ | |
731 | ||
732 | note_stores (PATTERN (insn), mark_reg_store); | |
733 | ||
734 | #ifdef AUTO_INC_DEC | |
735 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
736 | if (REG_NOTE_KIND (link) == REG_INC) | |
b1ec3c92 | 737 | mark_reg_store (XEXP (link, 0), NULL_RTX); |
38398762 RK |
738 | #endif |
739 | ||
333e0f7d RS |
740 | /* If INSN has multiple outputs, then any reg that dies here |
741 | and is used inside of an output | |
742 | must conflict with the other outputs. */ | |
743 | ||
744 | if (GET_CODE (PATTERN (insn)) == PARALLEL && !single_set (insn)) | |
745 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
746 | if (REG_NOTE_KIND (link) == REG_DEAD) | |
747 | { | |
748 | int used_in_output = 0; | |
749 | int i; | |
750 | rtx reg = XEXP (link, 0); | |
751 | ||
752 | for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--) | |
753 | { | |
754 | rtx set = XVECEXP (PATTERN (insn), 0, i); | |
755 | if (GET_CODE (set) == SET | |
756 | && GET_CODE (SET_DEST (set)) != REG | |
757 | && !rtx_equal_p (reg, SET_DEST (set)) | |
758 | && reg_overlap_mentioned_p (reg, SET_DEST (set))) | |
759 | used_in_output = 1; | |
760 | } | |
761 | if (used_in_output) | |
762 | mark_reg_conflicts (reg); | |
763 | } | |
764 | ||
38398762 RK |
765 | /* Mark any registers set in INSN and then never used. */ |
766 | ||
767 | while (n_regs_set > 0) | |
768 | if (find_regno_note (insn, REG_UNUSED, | |
769 | REGNO (regs_set[--n_regs_set]))) | |
770 | mark_reg_death (regs_set[n_regs_set]); | |
771 | } | |
772 | ||
773 | if (insn == basic_block_end[b]) | |
774 | break; | |
775 | insn = NEXT_INSN (insn); | |
776 | } | |
777 | } | |
778 | } | |
779 | /* Expand the preference information by looking for cases where one allocno | |
780 | dies in an insn that sets an allocno. If those two allocnos don't conflict, | |
781 | merge any preferences between those allocnos. */ | |
782 | ||
783 | static void | |
784 | expand_preferences () | |
785 | { | |
786 | rtx insn; | |
787 | rtx link; | |
788 | rtx set; | |
789 | ||
790 | /* We only try to handle the most common cases here. Most of the cases | |
791 | where this wins are reg-reg copies. */ | |
792 | ||
793 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
794 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' | |
795 | && (set = single_set (insn)) != 0 | |
796 | && GET_CODE (SET_DEST (set)) == REG | |
797 | && reg_allocno[REGNO (SET_DEST (set))] >= 0) | |
798 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
799 | if (REG_NOTE_KIND (link) == REG_DEAD | |
800 | && GET_CODE (XEXP (link, 0)) == REG | |
801 | && reg_allocno[REGNO (XEXP (link, 0))] >= 0 | |
802 | && ! CONFLICTP (reg_allocno[REGNO (SET_DEST (set))], | |
803 | reg_allocno[REGNO (XEXP (link, 0))]) | |
804 | && ! CONFLICTP (reg_allocno[REGNO (XEXP (link, 0))], | |
805 | reg_allocno[REGNO (SET_DEST (set))])) | |
806 | { | |
807 | int a1 = reg_allocno[REGNO (SET_DEST (set))]; | |
808 | int a2 = reg_allocno[REGNO (XEXP (link, 0))]; | |
809 | ||
810 | if (XEXP (link, 0) == SET_SRC (set)) | |
811 | { | |
812 | IOR_HARD_REG_SET (hard_reg_copy_preferences[a1], | |
813 | hard_reg_copy_preferences[a2]); | |
814 | IOR_HARD_REG_SET (hard_reg_copy_preferences[a2], | |
815 | hard_reg_copy_preferences[a1]); | |
816 | } | |
817 | ||
818 | IOR_HARD_REG_SET (hard_reg_preferences[a1], | |
819 | hard_reg_preferences[a2]); | |
820 | IOR_HARD_REG_SET (hard_reg_preferences[a2], | |
821 | hard_reg_preferences[a1]); | |
822 | IOR_HARD_REG_SET (hard_reg_full_preferences[a1], | |
823 | hard_reg_full_preferences[a2]); | |
824 | IOR_HARD_REG_SET (hard_reg_full_preferences[a2], | |
825 | hard_reg_full_preferences[a1]); | |
826 | } | |
827 | } | |
828 | \f | |
829 | /* Prune the preferences for global registers to exclude registers that cannot | |
830 | be used. | |
831 | ||
832 | Compute `regs_someone_prefers', which is a bitmask of the hard registers | |
833 | that are preferred by conflicting registers of lower priority. If possible, | |
834 | we will avoid using these registers. */ | |
835 | ||
836 | static void | |
837 | prune_preferences () | |
838 | { | |
839 | int i, j; | |
840 | int allocno; | |
841 | ||
842 | /* Scan least most important to most important. | |
843 | For each allocno, remove from preferences registers that cannot be used, | |
844 | either because of conflicts or register type. Then compute all registers | |
d45cf215 | 845 | preferred by each lower-priority register that conflicts. */ |
38398762 RK |
846 | |
847 | for (i = max_allocno - 1; i >= 0; i--) | |
848 | { | |
849 | HARD_REG_SET temp; | |
850 | ||
851 | allocno = allocno_order[i]; | |
852 | COPY_HARD_REG_SET (temp, hard_reg_conflicts[allocno]); | |
853 | ||
854 | if (allocno_calls_crossed[allocno] == 0) | |
855 | IOR_HARD_REG_SET (temp, fixed_reg_set); | |
856 | else | |
857 | IOR_HARD_REG_SET (temp, call_used_reg_set); | |
858 | ||
859 | IOR_COMPL_HARD_REG_SET | |
860 | (temp, | |
861 | reg_class_contents[(int) reg_preferred_class (allocno_reg[allocno])]); | |
862 | ||
863 | AND_COMPL_HARD_REG_SET (hard_reg_preferences[allocno], temp); | |
864 | AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[allocno], temp); | |
865 | AND_COMPL_HARD_REG_SET (hard_reg_full_preferences[allocno], temp); | |
866 | ||
867 | CLEAR_HARD_REG_SET (regs_someone_prefers[allocno]); | |
868 | ||
869 | /* Merge in the preferences of lower-priority registers (they have | |
870 | already been pruned). If we also prefer some of those registers, | |
871 | don't exclude them unless we are of a smaller size (in which case | |
872 | we want to give the lower-priority allocno the first chance for | |
873 | these registers). */ | |
874 | for (j = i + 1; j < max_allocno; j++) | |
99fd4012 RK |
875 | if (CONFLICTP (allocno, allocno_order[j]) |
876 | || CONFLICTP (allocno_order[j], allocno)) | |
38398762 RK |
877 | { |
878 | COPY_HARD_REG_SET (temp, | |
879 | hard_reg_full_preferences[allocno_order[j]]); | |
880 | if (allocno_size[allocno_order[j]] <= allocno_size[allocno]) | |
881 | AND_COMPL_HARD_REG_SET (temp, | |
882 | hard_reg_full_preferences[allocno]); | |
883 | ||
884 | IOR_HARD_REG_SET (regs_someone_prefers[allocno], temp); | |
885 | } | |
886 | } | |
887 | } | |
888 | \f | |
889 | /* Assign a hard register to ALLOCNO; look for one that is the beginning | |
890 | of a long enough stretch of hard regs none of which conflicts with ALLOCNO. | |
891 | The registers marked in PREFREGS are tried first. | |
892 | ||
893 | LOSERS, if non-zero, is a HARD_REG_SET indicating registers that cannot | |
894 | be used for this allocation. | |
895 | ||
b1ec3c92 CH |
896 | If ALT_REGS_P is zero, consider only the preferred class of ALLOCNO's reg. |
897 | Otherwise ignore that preferred class and use the alternate class. | |
38398762 RK |
898 | |
899 | If ACCEPT_CALL_CLOBBERED is nonzero, accept a call-clobbered hard reg that | |
900 | will have to be saved and restored at calls. | |
901 | ||
1d56e983 RS |
902 | RETRYING is nonzero if this is called from retry_global_alloc. |
903 | ||
38398762 RK |
904 | If we find one, record it in reg_renumber. |
905 | If not, do nothing. */ | |
906 | ||
907 | static void | |
b1ec3c92 | 908 | find_reg (allocno, losers, alt_regs_p, accept_call_clobbered, retrying) |
38398762 RK |
909 | int allocno; |
910 | HARD_REG_SET losers; | |
b1ec3c92 | 911 | int alt_regs_p; |
38398762 | 912 | int accept_call_clobbered; |
1d56e983 | 913 | int retrying; |
38398762 RK |
914 | { |
915 | register int i, best_reg, pass; | |
916 | #ifdef HARD_REG_SET | |
917 | register /* Declare it register if it's a scalar. */ | |
918 | #endif | |
1d56e983 | 919 | HARD_REG_SET used, used1, used2; |
38398762 | 920 | |
b1ec3c92 CH |
921 | enum reg_class class = (alt_regs_p |
922 | ? reg_alternate_class (allocno_reg[allocno]) | |
923 | : reg_preferred_class (allocno_reg[allocno])); | |
38398762 RK |
924 | enum machine_mode mode = PSEUDO_REGNO_MODE (allocno_reg[allocno]); |
925 | ||
926 | if (accept_call_clobbered) | |
927 | COPY_HARD_REG_SET (used1, call_fixed_reg_set); | |
928 | else if (allocno_calls_crossed[allocno] == 0) | |
929 | COPY_HARD_REG_SET (used1, fixed_reg_set); | |
930 | else | |
931 | COPY_HARD_REG_SET (used1, call_used_reg_set); | |
932 | ||
933 | /* Some registers should not be allocated in global-alloc. */ | |
934 | IOR_HARD_REG_SET (used1, no_global_alloc_regs); | |
935 | if (losers) | |
936 | IOR_HARD_REG_SET (used1, losers); | |
937 | ||
938 | IOR_COMPL_HARD_REG_SET (used1, reg_class_contents[(int) class]); | |
1d56e983 RS |
939 | COPY_HARD_REG_SET (used2, used1); |
940 | ||
38398762 RK |
941 | IOR_HARD_REG_SET (used1, hard_reg_conflicts[allocno]); |
942 | ||
d546b10a | 943 | #ifdef CLASS_CANNOT_CHANGE_SIZE |
b1f21e0a | 944 | if (REG_CHANGES_SIZE (allocno_reg[allocno])) |
d546b10a RK |
945 | IOR_HARD_REG_SET (used1, |
946 | reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE]); | |
947 | #endif | |
948 | ||
38398762 | 949 | /* Try each hard reg to see if it fits. Do this in two passes. |
d45cf215 | 950 | In the first pass, skip registers that are preferred by some other pseudo |
38398762 RK |
951 | to give it a better chance of getting one of those registers. Only if |
952 | we can't get a register when excluding those do we take one of them. | |
953 | However, we never allocate a register for the first time in pass 0. */ | |
954 | ||
955 | COPY_HARD_REG_SET (used, used1); | |
956 | IOR_COMPL_HARD_REG_SET (used, regs_used_so_far); | |
957 | IOR_HARD_REG_SET (used, regs_someone_prefers[allocno]); | |
958 | ||
959 | best_reg = -1; | |
960 | for (i = FIRST_PSEUDO_REGISTER, pass = 0; | |
961 | pass <= 1 && i >= FIRST_PSEUDO_REGISTER; | |
962 | pass++) | |
963 | { | |
964 | if (pass == 1) | |
965 | COPY_HARD_REG_SET (used, used1); | |
966 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
967 | { | |
968 | #ifdef REG_ALLOC_ORDER | |
969 | int regno = reg_alloc_order[i]; | |
970 | #else | |
971 | int regno = i; | |
972 | #endif | |
973 | if (! TEST_HARD_REG_BIT (used, regno) | |
1e326708 MH |
974 | && HARD_REGNO_MODE_OK (regno, mode) |
975 | && (allocno_calls_crossed[allocno] == 0 | |
976 | || accept_call_clobbered | |
977 | || ! HARD_REGNO_CALL_PART_CLOBBERED (regno, mode))) | |
38398762 RK |
978 | { |
979 | register int j; | |
980 | register int lim = regno + HARD_REGNO_NREGS (regno, mode); | |
981 | for (j = regno + 1; | |
982 | (j < lim | |
983 | && ! TEST_HARD_REG_BIT (used, j)); | |
984 | j++); | |
985 | if (j == lim) | |
986 | { | |
987 | best_reg = regno; | |
988 | break; | |
989 | } | |
990 | #ifndef REG_ALLOC_ORDER | |
991 | i = j; /* Skip starting points we know will lose */ | |
992 | #endif | |
993 | } | |
994 | } | |
995 | } | |
996 | ||
997 | /* See if there is a preferred register with the same class as the register | |
998 | we allocated above. Making this restriction prevents register | |
999 | preferencing from creating worse register allocation. | |
1000 | ||
1001 | Remove from the preferred registers and conflicting registers. Note that | |
1002 | additional conflicts may have been added after `prune_preferences' was | |
1003 | called. | |
1004 | ||
1005 | First do this for those register with copy preferences, then all | |
1006 | preferred registers. */ | |
1007 | ||
1008 | AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[allocno], used); | |
1009 | GO_IF_HARD_REG_SUBSET (hard_reg_copy_preferences[allocno], | |
1010 | reg_class_contents[(int) NO_REGS], no_copy_prefs); | |
1011 | ||
1012 | if (best_reg >= 0) | |
1013 | { | |
1014 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
1015 | if (TEST_HARD_REG_BIT (hard_reg_copy_preferences[allocno], i) | |
1016 | && HARD_REGNO_MODE_OK (i, mode) | |
1017 | && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg) | |
1018 | || reg_class_subset_p (REGNO_REG_CLASS (i), | |
1019 | REGNO_REG_CLASS (best_reg)) | |
1020 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg), | |
1021 | REGNO_REG_CLASS (i)))) | |
1022 | { | |
1023 | register int j; | |
1024 | register int lim = i + HARD_REGNO_NREGS (i, mode); | |
1025 | for (j = i + 1; | |
1026 | (j < lim | |
1027 | && ! TEST_HARD_REG_BIT (used, j) | |
1028 | && (REGNO_REG_CLASS (j) | |
1029 | == REGNO_REG_CLASS (best_reg + (j - i)) | |
1030 | || reg_class_subset_p (REGNO_REG_CLASS (j), | |
1031 | REGNO_REG_CLASS (best_reg + (j - i))) | |
1032 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)), | |
1033 | REGNO_REG_CLASS (j)))); | |
1034 | j++); | |
1035 | if (j == lim) | |
1036 | { | |
1037 | best_reg = i; | |
1038 | goto no_prefs; | |
1039 | } | |
1040 | } | |
1041 | } | |
1042 | no_copy_prefs: | |
1043 | ||
1044 | AND_COMPL_HARD_REG_SET (hard_reg_preferences[allocno], used); | |
1045 | GO_IF_HARD_REG_SUBSET (hard_reg_preferences[allocno], | |
1046 | reg_class_contents[(int) NO_REGS], no_prefs); | |
1047 | ||
1048 | if (best_reg >= 0) | |
1049 | { | |
1050 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
1051 | if (TEST_HARD_REG_BIT (hard_reg_preferences[allocno], i) | |
1052 | && HARD_REGNO_MODE_OK (i, mode) | |
1053 | && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg) | |
1054 | || reg_class_subset_p (REGNO_REG_CLASS (i), | |
1055 | REGNO_REG_CLASS (best_reg)) | |
1056 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg), | |
1057 | REGNO_REG_CLASS (i)))) | |
1058 | { | |
1059 | register int j; | |
1060 | register int lim = i + HARD_REGNO_NREGS (i, mode); | |
1061 | for (j = i + 1; | |
1062 | (j < lim | |
1063 | && ! TEST_HARD_REG_BIT (used, j) | |
1064 | && (REGNO_REG_CLASS (j) | |
1065 | == REGNO_REG_CLASS (best_reg + (j - i)) | |
1066 | || reg_class_subset_p (REGNO_REG_CLASS (j), | |
1067 | REGNO_REG_CLASS (best_reg + (j - i))) | |
1068 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)), | |
1069 | REGNO_REG_CLASS (j)))); | |
1070 | j++); | |
1071 | if (j == lim) | |
1072 | { | |
1073 | best_reg = i; | |
1074 | break; | |
1075 | } | |
1076 | } | |
1077 | } | |
1078 | no_prefs: | |
1079 | ||
cfcf04a6 RK |
1080 | /* If we haven't succeeded yet, try with caller-saves. |
1081 | We need not check to see if the current function has nonlocal | |
1082 | labels because we don't put any pseudos that are live over calls in | |
1083 | registers in that case. */ | |
1084 | ||
1d56e983 RS |
1085 | if (flag_caller_saves && best_reg < 0) |
1086 | { | |
1087 | /* Did not find a register. If it would be profitable to | |
1088 | allocate a call-clobbered register and save and restore it | |
1089 | around calls, do that. */ | |
1090 | if (! accept_call_clobbered | |
1091 | && allocno_calls_crossed[allocno] != 0 | |
1092 | && CALLER_SAVE_PROFITABLE (allocno_n_refs[allocno], | |
1093 | allocno_calls_crossed[allocno])) | |
1094 | { | |
6cad67d2 JL |
1095 | HARD_REG_SET new_losers; |
1096 | if (! losers) | |
1097 | CLEAR_HARD_REG_SET (new_losers); | |
1098 | else | |
1099 | COPY_HARD_REG_SET (new_losers, losers); | |
1100 | ||
1101 | IOR_HARD_REG_SET(new_losers, losing_caller_save_reg_set); | |
1102 | find_reg (allocno, new_losers, alt_regs_p, 1, retrying); | |
1d56e983 RS |
1103 | if (reg_renumber[allocno_reg[allocno]] >= 0) |
1104 | { | |
1105 | caller_save_needed = 1; | |
1106 | return; | |
1107 | } | |
1108 | } | |
1109 | } | |
1110 | ||
1111 | /* If we haven't succeeded yet, | |
1112 | see if some hard reg that conflicts with us | |
1113 | was utilized poorly by local-alloc. | |
1114 | If so, kick out the regs that were put there by local-alloc | |
1115 | so we can use it instead. */ | |
1116 | if (best_reg < 0 && !retrying | |
1117 | /* Let's not bother with multi-reg allocnos. */ | |
1118 | && allocno_size[allocno] == 1) | |
1119 | { | |
1120 | /* Count from the end, to find the least-used ones first. */ | |
1121 | for (i = FIRST_PSEUDO_REGISTER - 1; i >= 0; i--) | |
17a0a76d RK |
1122 | { |
1123 | #ifdef REG_ALLOC_ORDER | |
1124 | int regno = reg_alloc_order[i]; | |
1125 | #else | |
1126 | int regno = i; | |
1127 | #endif | |
34e56753 | 1128 | |
17a0a76d RK |
1129 | if (local_reg_n_refs[regno] != 0 |
1130 | /* Don't use a reg no good for this pseudo. */ | |
1131 | && ! TEST_HARD_REG_BIT (used2, regno) | |
d546b10a RK |
1132 | && HARD_REGNO_MODE_OK (regno, mode) |
1133 | #ifdef CLASS_CANNOT_CHANGE_SIZE | |
b1f21e0a | 1134 | && ! (REG_CHANGES_SIZE (allocno_reg[allocno]) |
d546b10a RK |
1135 | && (TEST_HARD_REG_BIT |
1136 | (reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE], | |
1137 | regno))) | |
1138 | #endif | |
1139 | ) | |
17a0a76d | 1140 | { |
7a17c588 JW |
1141 | /* We explicitly evaluate the divide results into temporary |
1142 | variables so as to avoid excess precision problems that occur | |
1143 | on a i386-unknown-sysv4.2 (unixware) host. */ | |
1144 | ||
1145 | double tmp1 = ((double) local_reg_n_refs[regno] | |
1146 | / local_reg_live_length[regno]); | |
1147 | double tmp2 = ((double) allocno_n_refs[allocno] | |
1148 | / allocno_live_length[allocno]); | |
1149 | ||
1150 | if (tmp1 < tmp2) | |
1151 | { | |
1152 | /* Hard reg REGNO was used less in total by local regs | |
1153 | than it would be used by this one allocno! */ | |
1154 | int k; | |
1155 | for (k = 0; k < max_regno; k++) | |
1156 | if (reg_renumber[k] >= 0) | |
1157 | { | |
1158 | int r = reg_renumber[k]; | |
1159 | int endregno | |
1160 | = r + HARD_REGNO_NREGS (r, PSEUDO_REGNO_MODE (k)); | |
34e56753 | 1161 | |
7a17c588 JW |
1162 | if (regno >= r && regno < endregno) |
1163 | reg_renumber[k] = -1; | |
1164 | } | |
17a0a76d | 1165 | |
7a17c588 JW |
1166 | best_reg = regno; |
1167 | break; | |
1168 | } | |
17a0a76d RK |
1169 | } |
1170 | } | |
1d56e983 RS |
1171 | } |
1172 | ||
38398762 RK |
1173 | /* Did we find a register? */ |
1174 | ||
1175 | if (best_reg >= 0) | |
1176 | { | |
1177 | register int lim, j; | |
1178 | HARD_REG_SET this_reg; | |
1179 | ||
1180 | /* Yes. Record it as the hard register of this pseudo-reg. */ | |
1181 | reg_renumber[allocno_reg[allocno]] = best_reg; | |
1182 | /* Also of any pseudo-regs that share with it. */ | |
1183 | if (reg_may_share[allocno_reg[allocno]]) | |
1184 | for (j = FIRST_PSEUDO_REGISTER; j < max_regno; j++) | |
1185 | if (reg_allocno[j] == allocno) | |
1186 | reg_renumber[j] = best_reg; | |
1187 | ||
1188 | /* Make a set of the hard regs being allocated. */ | |
1189 | CLEAR_HARD_REG_SET (this_reg); | |
1190 | lim = best_reg + HARD_REGNO_NREGS (best_reg, mode); | |
1191 | for (j = best_reg; j < lim; j++) | |
1192 | { | |
1193 | SET_HARD_REG_BIT (this_reg, j); | |
1194 | SET_HARD_REG_BIT (regs_used_so_far, j); | |
1d56e983 RS |
1195 | /* This is no longer a reg used just by local regs. */ |
1196 | local_reg_n_refs[j] = 0; | |
38398762 RK |
1197 | } |
1198 | /* For each other pseudo-reg conflicting with this one, | |
1199 | mark it as conflicting with the hard regs this one occupies. */ | |
1200 | lim = allocno; | |
1201 | for (j = 0; j < max_allocno; j++) | |
1202 | if (CONFLICTP (lim, j) || CONFLICTP (j, lim)) | |
1203 | { | |
1204 | IOR_HARD_REG_SET (hard_reg_conflicts[j], this_reg); | |
1205 | } | |
1206 | } | |
38398762 RK |
1207 | } |
1208 | \f | |
1209 | /* Called from `reload' to look for a hard reg to put pseudo reg REGNO in. | |
1210 | Perhaps it had previously seemed not worth a hard reg, | |
1211 | or perhaps its old hard reg has been commandeered for reloads. | |
1212 | FORBIDDEN_REGS indicates certain hard regs that may not be used, even if | |
1213 | they do not appear to be allocated. | |
1214 | If FORBIDDEN_REGS is zero, no regs are forbidden. */ | |
1215 | ||
1216 | void | |
1217 | retry_global_alloc (regno, forbidden_regs) | |
1218 | int regno; | |
1219 | HARD_REG_SET forbidden_regs; | |
1220 | { | |
1221 | int allocno = reg_allocno[regno]; | |
1222 | if (allocno >= 0) | |
1223 | { | |
1224 | /* If we have more than one register class, | |
1225 | first try allocating in the class that is cheapest | |
1226 | for this pseudo-reg. If that fails, try any reg. */ | |
1227 | if (N_REG_CLASSES > 1) | |
1d56e983 | 1228 | find_reg (allocno, forbidden_regs, 0, 0, 1); |
38398762 | 1229 | if (reg_renumber[regno] < 0 |
b1ec3c92 | 1230 | && reg_alternate_class (regno) != NO_REGS) |
1d56e983 | 1231 | find_reg (allocno, forbidden_regs, 1, 0, 1); |
38398762 RK |
1232 | |
1233 | /* If we found a register, modify the RTL for the register to | |
1234 | show the hard register, and mark that register live. */ | |
1235 | if (reg_renumber[regno] >= 0) | |
1236 | { | |
1237 | REGNO (regno_reg_rtx[regno]) = reg_renumber[regno]; | |
1238 | mark_home_live (regno); | |
1239 | } | |
1240 | } | |
1241 | } | |
1242 | \f | |
1243 | /* Record a conflict between register REGNO | |
1244 | and everything currently live. | |
1245 | REGNO must not be a pseudo reg that was allocated | |
1246 | by local_alloc; such numbers must be translated through | |
1247 | reg_renumber before calling here. */ | |
1248 | ||
1249 | static void | |
1250 | record_one_conflict (regno) | |
1251 | int regno; | |
1252 | { | |
1253 | register int j; | |
1254 | ||
1255 | if (regno < FIRST_PSEUDO_REGISTER) | |
1256 | /* When a hard register becomes live, | |
1257 | record conflicts with live pseudo regs. */ | |
1258 | for (j = 0; j < max_allocno; j++) | |
1259 | { | |
1260 | if (ALLOCNO_LIVE_P (j)) | |
1261 | SET_HARD_REG_BIT (hard_reg_conflicts[j], regno); | |
1262 | } | |
1263 | else | |
1264 | /* When a pseudo-register becomes live, | |
1265 | record conflicts first with hard regs, | |
1266 | then with other pseudo regs. */ | |
1267 | { | |
1268 | register int ialloc = reg_allocno[regno]; | |
1269 | register int ialloc_prod = ialloc * allocno_row_words; | |
1270 | IOR_HARD_REG_SET (hard_reg_conflicts[ialloc], hard_regs_live); | |
1271 | for (j = allocno_row_words - 1; j >= 0; j--) | |
1272 | { | |
1273 | #if 0 | |
1274 | int k; | |
1275 | for (k = 0; k < n_no_conflict_pairs; k++) | |
1276 | if (! ((j == no_conflict_pairs[k].allocno1 | |
1277 | && ialloc == no_conflict_pairs[k].allocno2) | |
1278 | || | |
1279 | (j == no_conflict_pairs[k].allocno2 | |
1280 | && ialloc == no_conflict_pairs[k].allocno1))) | |
1281 | #endif /* 0 */ | |
1282 | conflicts[ialloc_prod + j] |= allocnos_live[j]; | |
1283 | } | |
1284 | } | |
1285 | } | |
1286 | ||
1287 | /* Record all allocnos currently live as conflicting | |
1288 | with each other and with all hard regs currently live. | |
1289 | ALLOCNO_VEC is a vector of LEN allocnos, all allocnos that | |
1290 | are currently live. Their bits are also flagged in allocnos_live. */ | |
1291 | ||
1292 | static void | |
1293 | record_conflicts (allocno_vec, len) | |
1294 | register short *allocno_vec; | |
1295 | register int len; | |
1296 | { | |
1297 | register int allocno; | |
1298 | register int j; | |
1299 | register int ialloc_prod; | |
1300 | ||
1301 | while (--len >= 0) | |
1302 | { | |
1303 | allocno = allocno_vec[len]; | |
1304 | ialloc_prod = allocno * allocno_row_words; | |
1305 | IOR_HARD_REG_SET (hard_reg_conflicts[allocno], hard_regs_live); | |
1306 | for (j = allocno_row_words - 1; j >= 0; j--) | |
1307 | conflicts[ialloc_prod + j] |= allocnos_live[j]; | |
1308 | } | |
1309 | } | |
1310 | \f | |
1311 | /* Handle the case where REG is set by the insn being scanned, | |
1312 | during the forward scan to accumulate conflicts. | |
1313 | Store a 1 in regs_live or allocnos_live for this register, record how many | |
1314 | consecutive hardware registers it actually needs, | |
1315 | and record a conflict with all other registers already live. | |
1316 | ||
1317 | Note that even if REG does not remain alive after this insn, | |
1318 | we must mark it here as live, to ensure a conflict between | |
1319 | REG and any other regs set in this insn that really do live. | |
1320 | This is because those other regs could be considered after this. | |
1321 | ||
1322 | REG might actually be something other than a register; | |
1323 | if so, we do nothing. | |
1324 | ||
1325 | SETTER is 0 if this register was modified by an auto-increment (i.e., | |
a4c3ddd8 | 1326 | a REG_INC note was found for it). */ |
38398762 RK |
1327 | |
1328 | static void | |
a4c3ddd8 BS |
1329 | mark_reg_store (reg, setter) |
1330 | rtx reg, setter; | |
38398762 RK |
1331 | { |
1332 | register int regno; | |
38398762 RK |
1333 | |
1334 | /* WORD is which word of a multi-register group is being stored. | |
1335 | For the case where the store is actually into a SUBREG of REG. | |
1336 | Except we don't use it; I believe the entire REG needs to be | |
1337 | made live. */ | |
1338 | int word = 0; | |
1339 | ||
1340 | if (GET_CODE (reg) == SUBREG) | |
1341 | { | |
1342 | word = SUBREG_WORD (reg); | |
1343 | reg = SUBREG_REG (reg); | |
1344 | } | |
1345 | ||
1346 | if (GET_CODE (reg) != REG) | |
1347 | return; | |
1348 | ||
38398762 RK |
1349 | regs_set[n_regs_set++] = reg; |
1350 | ||
a4c3ddd8 | 1351 | if (setter && GET_CODE (setter) != CLOBBER) |
38398762 RK |
1352 | set_preference (reg, SET_SRC (setter)); |
1353 | ||
1354 | regno = REGNO (reg); | |
1355 | ||
38398762 RK |
1356 | /* Either this is one of the max_allocno pseudo regs not allocated, |
1357 | or it is or has a hardware reg. First handle the pseudo-regs. */ | |
1358 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1359 | { | |
1360 | if (reg_allocno[regno] >= 0) | |
1361 | { | |
1362 | SET_ALLOCNO_LIVE (reg_allocno[regno]); | |
1363 | record_one_conflict (regno); | |
1364 | } | |
1365 | } | |
a300b8d9 JW |
1366 | |
1367 | if (reg_renumber[regno] >= 0) | |
1368 | regno = reg_renumber[regno] /* + word */; | |
1369 | ||
38398762 | 1370 | /* Handle hardware regs (and pseudos allocated to hard regs). */ |
a300b8d9 | 1371 | if (regno < FIRST_PSEUDO_REGISTER && ! fixed_regs[regno]) |
38398762 RK |
1372 | { |
1373 | register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
1374 | while (regno < last) | |
1375 | { | |
1376 | record_one_conflict (regno); | |
1377 | SET_HARD_REG_BIT (hard_regs_live, regno); | |
1378 | regno++; | |
1379 | } | |
1380 | } | |
1381 | } | |
1382 | \f | |
1383 | /* Like mark_reg_set except notice just CLOBBERs; ignore SETs. */ | |
1384 | ||
1385 | static void | |
1386 | mark_reg_clobber (reg, setter) | |
1387 | rtx reg, setter; | |
1388 | { | |
a4c3ddd8 BS |
1389 | if (GET_CODE (setter) == CLOBBER) |
1390 | mark_reg_store (reg, setter); | |
333e0f7d RS |
1391 | } |
1392 | ||
1393 | /* Record that REG has conflicts with all the regs currently live. | |
1394 | Do not mark REG itself as live. */ | |
1395 | ||
1396 | static void | |
1397 | mark_reg_conflicts (reg) | |
1398 | rtx reg; | |
1399 | { | |
1400 | register int regno; | |
1401 | ||
1402 | if (GET_CODE (reg) == SUBREG) | |
1403 | reg = SUBREG_REG (reg); | |
1404 | ||
1405 | if (GET_CODE (reg) != REG) | |
1406 | return; | |
1407 | ||
1408 | regno = REGNO (reg); | |
1409 | ||
333e0f7d RS |
1410 | /* Either this is one of the max_allocno pseudo regs not allocated, |
1411 | or it is or has a hardware reg. First handle the pseudo-regs. */ | |
1412 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1413 | { | |
1414 | if (reg_allocno[regno] >= 0) | |
1415 | record_one_conflict (regno); | |
1416 | } | |
a300b8d9 JW |
1417 | |
1418 | if (reg_renumber[regno] >= 0) | |
1419 | regno = reg_renumber[regno]; | |
1420 | ||
333e0f7d | 1421 | /* Handle hardware regs (and pseudos allocated to hard regs). */ |
a300b8d9 | 1422 | if (regno < FIRST_PSEUDO_REGISTER && ! fixed_regs[regno]) |
333e0f7d RS |
1423 | { |
1424 | register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
1425 | while (regno < last) | |
1426 | { | |
1427 | record_one_conflict (regno); | |
1428 | regno++; | |
1429 | } | |
1430 | } | |
38398762 RK |
1431 | } |
1432 | \f | |
1433 | /* Mark REG as being dead (following the insn being scanned now). | |
1434 | Store a 0 in regs_live or allocnos_live for this register. */ | |
1435 | ||
1436 | static void | |
1437 | mark_reg_death (reg) | |
1438 | rtx reg; | |
1439 | { | |
1440 | register int regno = REGNO (reg); | |
1441 | ||
38398762 RK |
1442 | /* Either this is one of the max_allocno pseudo regs not allocated, |
1443 | or it is a hardware reg. First handle the pseudo-regs. */ | |
1444 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1445 | { | |
1446 | if (reg_allocno[regno] >= 0) | |
1447 | CLEAR_ALLOCNO_LIVE (reg_allocno[regno]); | |
1448 | } | |
a300b8d9 JW |
1449 | |
1450 | /* For pseudo reg, see if it has been assigned a hardware reg. */ | |
1451 | if (reg_renumber[regno] >= 0) | |
1452 | regno = reg_renumber[regno]; | |
1453 | ||
38398762 | 1454 | /* Handle hardware regs (and pseudos allocated to hard regs). */ |
a300b8d9 | 1455 | if (regno < FIRST_PSEUDO_REGISTER && ! fixed_regs[regno]) |
38398762 RK |
1456 | { |
1457 | /* Pseudo regs already assigned hardware regs are treated | |
1458 | almost the same as explicit hardware regs. */ | |
1459 | register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
1460 | while (regno < last) | |
1461 | { | |
1462 | CLEAR_HARD_REG_BIT (hard_regs_live, regno); | |
1463 | regno++; | |
1464 | } | |
1465 | } | |
1466 | } | |
1467 | ||
1468 | /* Mark hard reg REGNO as currently live, assuming machine mode MODE | |
1469 | for the value stored in it. MODE determines how many consecutive | |
1470 | registers are actually in use. Do not record conflicts; | |
1471 | it is assumed that the caller will do that. */ | |
1472 | ||
1473 | static void | |
1474 | mark_reg_live_nc (regno, mode) | |
1475 | register int regno; | |
1476 | enum machine_mode mode; | |
1477 | { | |
1478 | register int last = regno + HARD_REGNO_NREGS (regno, mode); | |
1479 | while (regno < last) | |
1480 | { | |
1481 | SET_HARD_REG_BIT (hard_regs_live, regno); | |
1482 | regno++; | |
1483 | } | |
1484 | } | |
1485 | \f | |
1486 | /* Try to set a preference for an allocno to a hard register. | |
1487 | We are passed DEST and SRC which are the operands of a SET. It is known | |
1488 | that SRC is a register. If SRC or the first operand of SRC is a register, | |
1489 | try to set a preference. If one of the two is a hard register and the other | |
1490 | is a pseudo-register, mark the preference. | |
1491 | ||
6dc42e49 | 1492 | Note that we are not as aggressive as local-alloc in trying to tie a |
38398762 RK |
1493 | pseudo-register to a hard register. */ |
1494 | ||
1495 | static void | |
1496 | set_preference (dest, src) | |
1497 | rtx dest, src; | |
1498 | { | |
1499 | int src_regno, dest_regno; | |
1500 | /* Amount to add to the hard regno for SRC, or subtract from that for DEST, | |
1501 | to compensate for subregs in SRC or DEST. */ | |
1502 | int offset = 0; | |
1503 | int i; | |
1504 | int copy = 1; | |
1505 | ||
1506 | if (GET_RTX_FORMAT (GET_CODE (src))[0] == 'e') | |
1507 | src = XEXP (src, 0), copy = 0; | |
1508 | ||
1509 | /* Get the reg number for both SRC and DEST. | |
1510 | If neither is a reg, give up. */ | |
1511 | ||
1512 | if (GET_CODE (src) == REG) | |
1513 | src_regno = REGNO (src); | |
1514 | else if (GET_CODE (src) == SUBREG && GET_CODE (SUBREG_REG (src)) == REG) | |
1515 | { | |
1516 | src_regno = REGNO (SUBREG_REG (src)); | |
1517 | offset += SUBREG_WORD (src); | |
1518 | } | |
1519 | else | |
1520 | return; | |
1521 | ||
1522 | if (GET_CODE (dest) == REG) | |
1523 | dest_regno = REGNO (dest); | |
1524 | else if (GET_CODE (dest) == SUBREG && GET_CODE (SUBREG_REG (dest)) == REG) | |
1525 | { | |
1526 | dest_regno = REGNO (SUBREG_REG (dest)); | |
1527 | offset -= SUBREG_WORD (dest); | |
1528 | } | |
1529 | else | |
1530 | return; | |
1531 | ||
1532 | /* Convert either or both to hard reg numbers. */ | |
1533 | ||
1534 | if (reg_renumber[src_regno] >= 0) | |
1535 | src_regno = reg_renumber[src_regno]; | |
1536 | ||
1537 | if (reg_renumber[dest_regno] >= 0) | |
1538 | dest_regno = reg_renumber[dest_regno]; | |
1539 | ||
1540 | /* Now if one is a hard reg and the other is a global pseudo | |
1541 | then give the other a preference. */ | |
1542 | ||
1543 | if (dest_regno < FIRST_PSEUDO_REGISTER && src_regno >= FIRST_PSEUDO_REGISTER | |
1544 | && reg_allocno[src_regno] >= 0) | |
1545 | { | |
1546 | dest_regno -= offset; | |
1547 | if (dest_regno >= 0 && dest_regno < FIRST_PSEUDO_REGISTER) | |
1548 | { | |
1549 | if (copy) | |
1550 | SET_REGBIT (hard_reg_copy_preferences, | |
1551 | reg_allocno[src_regno], dest_regno); | |
1552 | ||
1553 | SET_REGBIT (hard_reg_preferences, | |
1554 | reg_allocno[src_regno], dest_regno); | |
1555 | for (i = dest_regno; | |
1556 | i < dest_regno + HARD_REGNO_NREGS (dest_regno, GET_MODE (dest)); | |
1557 | i++) | |
1558 | SET_REGBIT (hard_reg_full_preferences, reg_allocno[src_regno], i); | |
1559 | } | |
1560 | } | |
1561 | ||
1562 | if (src_regno < FIRST_PSEUDO_REGISTER && dest_regno >= FIRST_PSEUDO_REGISTER | |
1563 | && reg_allocno[dest_regno] >= 0) | |
1564 | { | |
1565 | src_regno += offset; | |
1566 | if (src_regno >= 0 && src_regno < FIRST_PSEUDO_REGISTER) | |
1567 | { | |
1568 | if (copy) | |
1569 | SET_REGBIT (hard_reg_copy_preferences, | |
1570 | reg_allocno[dest_regno], src_regno); | |
1571 | ||
1572 | SET_REGBIT (hard_reg_preferences, | |
1573 | reg_allocno[dest_regno], src_regno); | |
1574 | for (i = src_regno; | |
1575 | i < src_regno + HARD_REGNO_NREGS (src_regno, GET_MODE (src)); | |
1576 | i++) | |
1577 | SET_REGBIT (hard_reg_full_preferences, reg_allocno[dest_regno], i); | |
1578 | } | |
1579 | } | |
1580 | } | |
1581 | \f | |
1582 | /* Indicate that hard register number FROM was eliminated and replaced with | |
1583 | an offset from hard register number TO. The status of hard registers live | |
1584 | at the start of a basic block is updated by replacing a use of FROM with | |
1585 | a use of TO. */ | |
1586 | ||
1587 | void | |
1588 | mark_elimination (from, to) | |
1589 | int from, to; | |
1590 | { | |
1591 | int i; | |
1592 | ||
1593 | for (i = 0; i < n_basic_blocks; i++) | |
916b1701 | 1594 | if (REGNO_REG_SET_P (basic_block_live_at_start[i], from)) |
38398762 | 1595 | { |
916b1701 MM |
1596 | CLEAR_REGNO_REG_SET (basic_block_live_at_start[i], from); |
1597 | SET_REGNO_REG_SET (basic_block_live_at_start[i], to); | |
38398762 RK |
1598 | } |
1599 | } | |
1600 | \f | |
cad6f7d0 BS |
1601 | /* Used for communication between the following functions. Holds the |
1602 | current life information. */ | |
1603 | static regset live_relevant_regs; | |
1604 | ||
1605 | /* Record in live_relevant_regs that register REG became live. This | |
1606 | is called via note_stores. */ | |
1607 | static void | |
1608 | reg_becomes_live (reg, setter) | |
1609 | rtx reg; | |
1610 | rtx setter ATTRIBUTE_UNUSED; | |
1611 | { | |
1612 | int regno; | |
1613 | ||
1614 | if (GET_CODE (reg) == SUBREG) | |
1615 | reg = SUBREG_REG (reg); | |
1616 | ||
1617 | if (GET_CODE (reg) != REG) | |
1618 | return; | |
1619 | ||
1620 | regno = REGNO (reg); | |
1621 | if (regno < FIRST_PSEUDO_REGISTER) | |
1622 | { | |
1623 | int nregs = HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
1624 | while (nregs-- > 0) | |
1625 | SET_REGNO_REG_SET (live_relevant_regs, regno++); | |
1626 | } | |
1627 | else if (reg_renumber[regno] >= 0) | |
1628 | SET_REGNO_REG_SET (live_relevant_regs, regno); | |
1629 | } | |
1630 | ||
1631 | /* Record in live_relevant_regs that register REGNO died. */ | |
1632 | static void | |
1633 | reg_dies (regno, mode) | |
1634 | int regno; | |
1635 | enum machine_mode mode; | |
1636 | { | |
1637 | if (regno < FIRST_PSEUDO_REGISTER) | |
1638 | { | |
1639 | int nregs = HARD_REGNO_NREGS (regno, mode); | |
1640 | while (nregs-- > 0) | |
1641 | CLEAR_REGNO_REG_SET (live_relevant_regs, regno++); | |
1642 | } | |
1643 | else | |
1644 | CLEAR_REGNO_REG_SET (live_relevant_regs, regno); | |
1645 | } | |
1646 | ||
1647 | /* Walk the insns of the current function and build reload_insn_chain, | |
1648 | and record register life information. */ | |
1649 | static void | |
1650 | build_insn_chain (first) | |
1651 | rtx first; | |
1652 | { | |
1653 | struct insn_chain **p = &reload_insn_chain; | |
1654 | struct insn_chain *prev = 0; | |
1655 | int b = 0; | |
1656 | ||
1657 | live_relevant_regs = ALLOCA_REG_SET (); | |
1658 | ||
1659 | for (; first; first = NEXT_INSN (first)) | |
1660 | { | |
1661 | struct insn_chain *c; | |
1662 | ||
1663 | if (first == basic_block_head[b]) | |
1664 | { | |
1665 | int i; | |
1666 | CLEAR_REG_SET (live_relevant_regs); | |
1667 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
1668 | if (REGNO_REG_SET_P (basic_block_live_at_start[b], i) | |
1669 | && ! TEST_HARD_REG_BIT (eliminable_regset, i)) | |
1670 | SET_REGNO_REG_SET (live_relevant_regs, i); | |
1671 | ||
1672 | for (; i < max_regno; i++) | |
1673 | if (reg_renumber[i] >= 0 | |
1674 | && REGNO_REG_SET_P (basic_block_live_at_start[b], i)) | |
1675 | SET_REGNO_REG_SET (live_relevant_regs, i); | |
1676 | } | |
1677 | ||
1678 | if (GET_CODE (first) != NOTE && GET_CODE (first) != BARRIER) | |
1679 | { | |
1680 | c = new_insn_chain (); | |
1681 | c->prev = prev; | |
1682 | prev = c; | |
1683 | *p = c; | |
1684 | p = &c->next; | |
1685 | c->insn = first; | |
1686 | c->block = b; | |
1687 | ||
1688 | COPY_REG_SET (c->live_before, live_relevant_regs); | |
1689 | ||
1690 | if (GET_RTX_CLASS (GET_CODE (first)) == 'i') | |
1691 | { | |
1692 | rtx link; | |
1693 | ||
1694 | /* Mark the death of everything that dies in this instruction. */ | |
1695 | ||
1696 | for (link = REG_NOTES (first); link; link = XEXP (link, 1)) | |
1697 | if (REG_NOTE_KIND (link) == REG_DEAD | |
1698 | && GET_CODE (XEXP (link, 0)) == REG) | |
1699 | reg_dies (REGNO (XEXP (link, 0)), GET_MODE (XEXP (link, 0))); | |
1700 | ||
1701 | /* Mark everything born in this instruction as live. */ | |
1702 | ||
1703 | note_stores (PATTERN (first), reg_becomes_live); | |
1704 | } | |
1705 | ||
1706 | /* Remember which registers are live at the end of the insn, before | |
1707 | killing those with REG_UNUSED notes. */ | |
1708 | COPY_REG_SET (c->live_after, live_relevant_regs); | |
1709 | ||
1710 | if (GET_RTX_CLASS (GET_CODE (first)) == 'i') | |
1711 | { | |
1712 | rtx link; | |
1713 | ||
1714 | /* Mark anything that is set in this insn and then unused as dying. */ | |
1715 | ||
1716 | for (link = REG_NOTES (first); link; link = XEXP (link, 1)) | |
1717 | if (REG_NOTE_KIND (link) == REG_UNUSED | |
1718 | && GET_CODE (XEXP (link, 0)) == REG) | |
1719 | reg_dies (REGNO (XEXP (link, 0)), GET_MODE (XEXP (link, 0))); | |
1720 | } | |
1721 | } | |
1722 | ||
1723 | if (first == basic_block_end[b]) | |
1724 | b++; | |
1725 | } | |
1726 | FREE_REG_SET (live_relevant_regs); | |
1727 | *p = 0; | |
1728 | } | |
1729 | \f | |
38398762 RK |
1730 | /* Print debugging trace information if -greg switch is given, |
1731 | showing the information on which the allocation decisions are based. */ | |
1732 | ||
1733 | static void | |
1734 | dump_conflicts (file) | |
1735 | FILE *file; | |
1736 | { | |
1737 | register int i; | |
1738 | register int has_preferences; | |
a300b8d9 JW |
1739 | register int nregs; |
1740 | nregs = 0; | |
1741 | for (i = 0; i < max_allocno; i++) | |
1742 | { | |
1743 | if (reg_renumber[allocno_reg[allocno_order[i]]] >= 0) | |
1744 | continue; | |
1745 | nregs++; | |
1746 | } | |
1747 | fprintf (file, ";; %d regs to allocate:", nregs); | |
38398762 RK |
1748 | for (i = 0; i < max_allocno; i++) |
1749 | { | |
1750 | int j; | |
a300b8d9 JW |
1751 | if (reg_renumber[allocno_reg[allocno_order[i]]] >= 0) |
1752 | continue; | |
38398762 RK |
1753 | fprintf (file, " %d", allocno_reg[allocno_order[i]]); |
1754 | for (j = 0; j < max_regno; j++) | |
1755 | if (reg_allocno[j] == allocno_order[i] | |
1756 | && j != allocno_reg[allocno_order[i]]) | |
1757 | fprintf (file, "+%d", j); | |
1758 | if (allocno_size[allocno_order[i]] != 1) | |
1759 | fprintf (file, " (%d)", allocno_size[allocno_order[i]]); | |
1760 | } | |
1761 | fprintf (file, "\n"); | |
1762 | ||
1763 | for (i = 0; i < max_allocno; i++) | |
1764 | { | |
1765 | register int j; | |
1766 | fprintf (file, ";; %d conflicts:", allocno_reg[i]); | |
1767 | for (j = 0; j < max_allocno; j++) | |
1768 | if (CONFLICTP (i, j) || CONFLICTP (j, i)) | |
1769 | fprintf (file, " %d", allocno_reg[j]); | |
1770 | for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) | |
1771 | if (TEST_HARD_REG_BIT (hard_reg_conflicts[i], j)) | |
1772 | fprintf (file, " %d", j); | |
1773 | fprintf (file, "\n"); | |
1774 | ||
1775 | has_preferences = 0; | |
1776 | for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) | |
1777 | if (TEST_HARD_REG_BIT (hard_reg_preferences[i], j)) | |
1778 | has_preferences = 1; | |
1779 | ||
1780 | if (! has_preferences) | |
1781 | continue; | |
1782 | fprintf (file, ";; %d preferences:", allocno_reg[i]); | |
1783 | for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) | |
1784 | if (TEST_HARD_REG_BIT (hard_reg_preferences[i], j)) | |
1785 | fprintf (file, " %d", j); | |
1786 | fprintf (file, "\n"); | |
1787 | } | |
1788 | fprintf (file, "\n"); | |
1789 | } | |
1790 | ||
1791 | void | |
1792 | dump_global_regs (file) | |
1793 | FILE *file; | |
1794 | { | |
1795 | register int i, j; | |
1796 | ||
1797 | fprintf (file, ";; Register dispositions:\n"); | |
1798 | for (i = FIRST_PSEUDO_REGISTER, j = 0; i < max_regno; i++) | |
1799 | if (reg_renumber[i] >= 0) | |
1800 | { | |
1801 | fprintf (file, "%d in %d ", i, reg_renumber[i]); | |
1802 | if (++j % 6 == 0) | |
1803 | fprintf (file, "\n"); | |
1804 | } | |
1805 | ||
1806 | fprintf (file, "\n\n;; Hard regs used: "); | |
1807 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
1808 | if (regs_ever_live[i]) | |
1809 | fprintf (file, " %d", i); | |
1810 | fprintf (file, "\n\n"); | |
1811 | } |