1 /* Allocate registers for pseudo-registers that span basic blocks.
2 Copyright (C) 1987, 1988, 1991, 1994 Free Software Foundation, Inc.
4 This file is part of GNU CC.
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)
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.
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, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
26 #include "basic-block.h"
27 #include "hard-reg-set.h"
29 #include "insn-config.h"
32 /* This pass of the compiler performs global register allocation.
33 It assigns hard register numbers to all the pseudo registers
34 that were not handled in local_alloc. Assignments are recorded
35 in the vector reg_renumber, not by changing the rtl code.
36 (Such changes are made by final). The entry point is
37 the function global_alloc.
39 After allocation is complete, the reload pass is run as a subroutine
40 of this pass, so that when a pseudo reg loses its hard reg due to
41 spilling it is possible to make a second attempt to find a hard
42 reg for it. The reload pass is independent in other respects
43 and it is run even when stupid register allocation is in use.
45 1. count the pseudo-registers still needing allocation
46 and assign allocation-numbers (allocnos) to them.
47 Set up tables reg_allocno and allocno_reg to map
48 reg numbers to allocnos and vice versa.
49 max_allocno gets the number of allocnos in use.
51 2. Allocate a max_allocno by max_allocno conflict bit matrix and clear it.
52 Allocate a max_allocno by FIRST_PSEUDO_REGISTER conflict matrix
53 for conflicts between allocnos and explicit hard register use
54 (which includes use of pseudo-registers allocated by local_alloc).
56 3. for each basic block
57 walk forward through the block, recording which
58 unallocated registers and which hardware registers are live.
59 Build the conflict matrix between the unallocated registers
60 and another of unallocated registers versus hardware registers.
61 Also record the preferred hardware registers
62 for each unallocated one.
64 4. Sort a table of the allocnos into order of
65 desirability of the variables.
67 5. Allocate the variables in that order; each if possible into
68 a preferred register, else into another register. */
70 /* Number of pseudo-registers still requiring allocation
71 (not allocated by local_allocate). */
73 static int max_allocno;
75 /* Indexed by (pseudo) reg number, gives the allocno, or -1
76 for pseudo registers already allocated by local_allocate. */
78 static int *reg_allocno;
80 /* Indexed by allocno, gives the reg number. */
82 static int *allocno_reg;
84 /* A vector of the integers from 0 to max_allocno-1,
85 sorted in the order of first-to-be-allocated first. */
87 static int *allocno_order;
89 /* Indexed by an allocno, gives the number of consecutive
90 hard registers needed by that pseudo reg. */
92 static int *allocno_size;
94 /* Indexed by (pseudo) reg number, gives the number of another
95 lower-numbered pseudo reg which can share a hard reg with this pseudo
96 *even if the two pseudos would otherwise appear to conflict*. */
98 static int *reg_may_share;
100 /* Define the number of bits in each element of `conflicts' and what
101 type that element has. We use the largest integer format on the
104 #define INT_BITS HOST_BITS_PER_WIDE_INT
105 #define INT_TYPE HOST_WIDE_INT
107 /* max_allocno by max_allocno array of bits,
108 recording whether two allocno's conflict (can't go in the same
111 `conflicts' is not symmetric; a conflict between allocno's i and j
112 is recorded either in element i,j or in element j,i. */
114 static INT_TYPE *conflicts;
116 /* Number of ints require to hold max_allocno bits.
117 This is the length of a row in `conflicts'. */
119 static int allocno_row_words;
121 /* Two macros to test or store 1 in an element of `conflicts'. */
123 #define CONFLICTP(I, J) \
124 (conflicts[(I) * allocno_row_words + (J) / INT_BITS] \
125 & ((INT_TYPE) 1 << ((J) % INT_BITS)))
127 #define SET_CONFLICT(I, J) \
128 (conflicts[(I) * allocno_row_words + (J) / INT_BITS] \
129 |= ((INT_TYPE) 1 << ((J) % INT_BITS)))
131 /* Set of hard regs currently live (during scan of all insns). */
133 static HARD_REG_SET hard_regs_live;
135 /* Indexed by N, set of hard regs conflicting with allocno N. */
137 static HARD_REG_SET *hard_reg_conflicts;
139 /* Indexed by N, set of hard regs preferred by allocno N.
140 This is used to make allocnos go into regs that are copied to or from them,
141 when possible, to reduce register shuffling. */
143 static HARD_REG_SET *hard_reg_preferences;
145 /* Similar, but just counts register preferences made in simple copy
146 operations, rather than arithmetic. These are given priority because
147 we can always eliminate an insn by using these, but using a register
148 in the above list won't always eliminate an insn. */
150 static HARD_REG_SET *hard_reg_copy_preferences;
152 /* Similar to hard_reg_preferences, but includes bits for subsequent
153 registers when an allocno is multi-word. The above variable is used for
154 allocation while this is used to build reg_someone_prefers, below. */
156 static HARD_REG_SET *hard_reg_full_preferences;
158 /* Indexed by N, set of hard registers that some later allocno has a
161 static HARD_REG_SET *regs_someone_prefers;
163 /* Set of registers that global-alloc isn't supposed to use. */
165 static HARD_REG_SET no_global_alloc_regs;
167 /* Set of registers used so far. */
169 static HARD_REG_SET regs_used_so_far;
171 /* Number of calls crossed by each allocno. */
173 static int *allocno_calls_crossed;
175 /* Number of refs (weighted) to each allocno. */
177 static int *allocno_n_refs;
179 /* Guess at live length of each allocno.
180 This is actually the max of the live lengths of the regs. */
182 static int *allocno_live_length;
184 /* Number of refs (weighted) to each hard reg, as used by local alloc.
185 It is zero for a reg that contains global pseudos or is explicitly used. */
187 static int local_reg_n_refs[FIRST_PSEUDO_REGISTER];
189 /* Guess at live length of each hard reg, as used by local alloc.
190 This is actually the sum of the live lengths of the specific regs. */
192 static int local_reg_live_length[FIRST_PSEUDO_REGISTER];
194 /* Test a bit in TABLE, a vector of HARD_REG_SETs,
195 for vector element I, and hard register number J. */
197 #define REGBITP(TABLE, I, J) TEST_HARD_REG_BIT (TABLE[I], J)
199 /* Set to 1 a bit in a vector of HARD_REG_SETs. Works like REGBITP. */
201 #define SET_REGBIT(TABLE, I, J) SET_HARD_REG_BIT (TABLE[I], J)
203 /* Bit mask for allocnos live at current point in the scan. */
205 static INT_TYPE *allocnos_live;
207 /* Test, set or clear bit number I in allocnos_live,
208 a bit vector indexed by allocno. */
210 #define ALLOCNO_LIVE_P(I) \
211 (allocnos_live[(I) / INT_BITS] & ((INT_TYPE) 1 << ((I) % INT_BITS)))
213 #define SET_ALLOCNO_LIVE(I) \
214 (allocnos_live[(I) / INT_BITS] |= ((INT_TYPE) 1 << ((I) % INT_BITS)))
216 #define CLEAR_ALLOCNO_LIVE(I) \
217 (allocnos_live[(I) / INT_BITS] &= ~((INT_TYPE) 1 << ((I) % INT_BITS)))
219 /* This is turned off because it doesn't work right for DImode.
220 (And it is only used for DImode, so the other cases are worthless.)
221 The problem is that it isn't true that there is NO possibility of conflict;
222 only that there is no conflict if the two pseudos get the exact same regs.
223 If they were allocated with a partial overlap, there would be a conflict.
224 We can't safely turn off the conflict unless we have another way to
225 prevent the partial overlap.
227 Idea: change hard_reg_conflicts so that instead of recording which
228 hard regs the allocno may not overlap, it records where the allocno
229 may not start. Change both where it is used and where it is updated.
230 Then there is a way to record that (reg:DI 108) may start at 10
231 but not at 9 or 11. There is still the question of how to record
232 this semi-conflict between two pseudos. */
234 /* Reg pairs for which conflict after the current insn
235 is inhibited by a REG_NO_CONFLICT note.
236 If the table gets full, we ignore any other notes--that is conservative. */
237 #define NUM_NO_CONFLICT_PAIRS 4
238 /* Number of pairs in use in this insn. */
239 int n_no_conflict_pairs;
240 static struct { int allocno1, allocno2;}
241 no_conflict_pairs[NUM_NO_CONFLICT_PAIRS];
244 /* Record all regs that are set in any one insn.
245 Communication from mark_reg_{store,clobber} and global_conflicts. */
247 static rtx *regs_set;
248 static int n_regs_set;
250 /* All registers that can be eliminated. */
252 static HARD_REG_SET eliminable_regset;
254 static int allocno_compare PROTO((int *, int *));
255 static void global_conflicts PROTO((void));
256 static void expand_preferences PROTO((void));
257 static void prune_preferences PROTO((void));
258 static void find_reg PROTO((int, HARD_REG_SET, int, int, int));
259 static void record_one_conflict PROTO((int));
260 static void record_conflicts PROTO((short *, int));
261 static void mark_reg_store PROTO((rtx, rtx));
262 static void mark_reg_clobber PROTO((rtx, rtx));
263 static void mark_reg_conflicts PROTO((rtx));
264 static void mark_reg_death PROTO((rtx));
265 static void mark_reg_live_nc PROTO((int, enum machine_mode));
266 static void set_preference PROTO((rtx, rtx));
267 static void dump_conflicts PROTO((FILE *));
269 /* Perform allocation of pseudo-registers not allocated by local_alloc.
270 FILE is a file to output debugging information on,
271 or zero if such output is not desired.
273 Return value is nonzero if reload failed
274 and we must not do any more for this function. */
280 #ifdef ELIMINABLE_REGS
281 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
284 = (! flag_omit_frame_pointer
285 #ifdef EXIT_IGNORE_STACK
286 || (current_function_calls_alloca && EXIT_IGNORE_STACK)
288 || FRAME_POINTER_REQUIRED);
295 /* A machine may have certain hard registers that
296 are safe to use only within a basic block. */
298 CLEAR_HARD_REG_SET (no_global_alloc_regs);
299 #ifdef OVERLAPPING_REGNO_P
300 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
301 if (OVERLAPPING_REGNO_P (i))
302 SET_HARD_REG_BIT (no_global_alloc_regs, i);
305 /* Build the regset of all eliminable registers and show we can't use those
306 that we already know won't be eliminated. */
307 #ifdef ELIMINABLE_REGS
308 for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++)
310 SET_HARD_REG_BIT (eliminable_regset, eliminables[i].from);
312 if (! CAN_ELIMINATE (eliminables[i].from, eliminables[i].to)
313 || (eliminables[i].to == STACK_POINTER_REGNUM && need_fp))
314 SET_HARD_REG_BIT (no_global_alloc_regs, eliminables[i].from);
316 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
317 SET_HARD_REG_BIT (eliminable_regset, HARD_FRAME_POINTER_REGNUM);
319 SET_HARD_REG_BIT (no_global_alloc_regs, HARD_FRAME_POINTER_REGNUM);
323 SET_HARD_REG_BIT (eliminable_regset, FRAME_POINTER_REGNUM);
325 SET_HARD_REG_BIT (no_global_alloc_regs, FRAME_POINTER_REGNUM);
328 /* Track which registers have already been used. Start with registers
329 explicitly in the rtl, then registers allocated by local register
332 CLEAR_HARD_REG_SET (regs_used_so_far);
333 #ifdef LEAF_REGISTERS
334 /* If we are doing the leaf function optimization, and this is a leaf
335 function, it means that the registers that take work to save are those
336 that need a register window. So prefer the ones that can be used in
340 static char leaf_regs[] = LEAF_REGISTERS;
342 if (only_leaf_regs_used () && leaf_function_p ())
343 cheap_regs = leaf_regs;
345 cheap_regs = call_used_regs;
346 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
347 if (regs_ever_live[i] || cheap_regs[i])
348 SET_HARD_REG_BIT (regs_used_so_far, i);
351 /* We consider registers that do not have to be saved over calls as if
352 they were already used since there is no cost in using them. */
353 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
354 if (regs_ever_live[i] || call_used_regs[i])
355 SET_HARD_REG_BIT (regs_used_so_far, i);
358 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
359 if (reg_renumber[i] >= 0)
360 SET_HARD_REG_BIT (regs_used_so_far, reg_renumber[i]);
362 /* Establish mappings from register number to allocation number
363 and vice versa. In the process, count the allocnos. */
365 reg_allocno = (int *) alloca (max_regno * sizeof (int));
367 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
370 /* Initialize the shared-hard-reg mapping
371 from the list of pairs that may share. */
372 reg_may_share = (int *) alloca (max_regno * sizeof (int));
373 bzero ((char *) reg_may_share, max_regno * sizeof (int));
374 for (x = regs_may_share; x; x = XEXP (XEXP (x, 1), 1))
376 int r1 = REGNO (XEXP (x, 0));
377 int r2 = REGNO (XEXP (XEXP (x, 1), 0));
379 reg_may_share[r1] = r2;
381 reg_may_share[r2] = r1;
384 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
385 /* Note that reg_live_length[i] < 0 indicates a "constant" reg
386 that we are supposed to refrain from putting in a hard reg.
387 -2 means do make an allocno but don't allocate it. */
388 if (reg_n_refs[i] != 0 && reg_renumber[i] < 0 && reg_live_length[i] != -1
389 /* Don't allocate pseudos that cross calls,
390 if this function receives a nonlocal goto. */
391 && (! current_function_has_nonlocal_label
392 || reg_n_calls_crossed[i] == 0))
394 if (reg_may_share[i] && reg_allocno[reg_may_share[i]] >= 0)
395 reg_allocno[i] = reg_allocno[reg_may_share[i]];
397 reg_allocno[i] = max_allocno++;
398 if (reg_live_length[i] == 0)
404 allocno_reg = (int *) alloca (max_allocno * sizeof (int));
405 allocno_size = (int *) alloca (max_allocno * sizeof (int));
406 allocno_calls_crossed = (int *) alloca (max_allocno * sizeof (int));
407 allocno_n_refs = (int *) alloca (max_allocno * sizeof (int));
408 allocno_live_length = (int *) alloca (max_allocno * sizeof (int));
409 bzero ((char *) allocno_size, max_allocno * sizeof (int));
410 bzero ((char *) allocno_calls_crossed, max_allocno * sizeof (int));
411 bzero ((char *) allocno_n_refs, max_allocno * sizeof (int));
412 bzero ((char *) allocno_live_length, max_allocno * sizeof (int));
414 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
415 if (reg_allocno[i] >= 0)
417 int allocno = reg_allocno[i];
418 allocno_reg[allocno] = i;
419 allocno_size[allocno] = PSEUDO_REGNO_SIZE (i);
420 allocno_calls_crossed[allocno] += reg_n_calls_crossed[i];
421 allocno_n_refs[allocno] += reg_n_refs[i];
422 if (allocno_live_length[allocno] < reg_live_length[i])
423 allocno_live_length[allocno] = reg_live_length[i];
426 /* Calculate amount of usage of each hard reg by pseudos
427 allocated by local-alloc. This is to see if we want to
429 bzero ((char *) local_reg_live_length, sizeof local_reg_live_length);
430 bzero ((char *) local_reg_n_refs, sizeof local_reg_n_refs);
431 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
432 if (reg_allocno[i] < 0 && reg_renumber[i] >= 0)
434 int regno = reg_renumber[i];
435 int endregno = regno + HARD_REGNO_NREGS (regno, PSEUDO_REGNO_MODE (i));
438 for (j = regno; j < endregno; j++)
440 local_reg_n_refs[j] += reg_n_refs[i];
441 local_reg_live_length[j] += reg_live_length[i];
445 /* We can't override local-alloc for a reg used not just by local-alloc. */
446 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
447 if (regs_ever_live[i])
448 local_reg_n_refs[i] = 0;
450 /* Likewise for regs used in a SCRATCH. */
451 for (i = 0; i < scratch_list_length; i++)
454 int regno = REGNO (scratch_list[i]);
455 int lim = regno + HARD_REGNO_NREGS (regno, GET_MODE (scratch_list[i]));
458 for (j = regno; j < lim; j++)
459 local_reg_n_refs[j] = 0;
462 /* Allocate the space for the conflict and preference tables and
466 = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET));
467 bzero ((char *) hard_reg_conflicts, max_allocno * sizeof (HARD_REG_SET));
470 = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET));
471 bzero ((char *) hard_reg_preferences, max_allocno * sizeof (HARD_REG_SET));
473 hard_reg_copy_preferences
474 = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET));
475 bzero ((char *) hard_reg_copy_preferences,
476 max_allocno * sizeof (HARD_REG_SET));
478 hard_reg_full_preferences
479 = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET));
480 bzero ((char *) hard_reg_full_preferences,
481 max_allocno * sizeof (HARD_REG_SET));
484 = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET));
485 bzero ((char *) regs_someone_prefers, max_allocno * sizeof (HARD_REG_SET));
487 allocno_row_words = (max_allocno + INT_BITS - 1) / INT_BITS;
489 conflicts = (INT_TYPE *) alloca (max_allocno * allocno_row_words
490 * sizeof (INT_TYPE));
491 bzero ((char *) conflicts,
492 max_allocno * allocno_row_words * sizeof (INT_TYPE));
494 allocnos_live = (INT_TYPE *) alloca (allocno_row_words * sizeof (INT_TYPE));
496 /* If there is work to be done (at least one reg to allocate),
497 perform global conflict analysis and allocate the regs. */
501 /* Scan all the insns and compute the conflicts among allocnos
502 and between allocnos and hard regs. */
506 /* Eliminate conflicts between pseudos and eliminable registers. If
507 the register is not eliminated, the pseudo won't really be able to
508 live in the eliminable register, so the conflict doesn't matter.
509 If we do eliminate the register, the conflict will no longer exist.
510 So in either case, we can ignore the conflict. Likewise for
513 for (i = 0; i < max_allocno; i++)
515 AND_COMPL_HARD_REG_SET (hard_reg_conflicts[i], eliminable_regset);
516 AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[i],
518 AND_COMPL_HARD_REG_SET (hard_reg_preferences[i], eliminable_regset);
521 /* Try to expand the preferences by merging them between allocnos. */
523 expand_preferences ();
525 /* Determine the order to allocate the remaining pseudo registers. */
527 allocno_order = (int *) alloca (max_allocno * sizeof (int));
528 for (i = 0; i < max_allocno; i++)
529 allocno_order[i] = i;
531 /* Default the size to 1, since allocno_compare uses it to divide by.
532 Also convert allocno_live_length of zero to -1. A length of zero
533 can occur when all the registers for that allocno have reg_live_length
534 equal to -2. In this case, we want to make an allocno, but not
535 allocate it. So avoid the divide-by-zero and set it to a low
538 for (i = 0; i < max_allocno; i++)
540 if (allocno_size[i] == 0)
542 if (allocno_live_length[i] == 0)
543 allocno_live_length[i] = -1;
546 qsort (allocno_order, max_allocno, sizeof (int), allocno_compare);
548 prune_preferences ();
551 dump_conflicts (file);
553 /* Try allocating them, one by one, in that order,
554 except for parameters marked with reg_live_length[regno] == -2. */
556 for (i = 0; i < max_allocno; i++)
557 if (reg_live_length[allocno_reg[allocno_order[i]]] >= 0)
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)
564 find_reg (allocno_order[i], HARD_CONST (0), 0, 0, 0);
565 if (reg_renumber[allocno_reg[allocno_order[i]]] >= 0)
568 if (reg_alternate_class (allocno_reg[allocno_order[i]]) != NO_REGS)
569 find_reg (allocno_order[i], HARD_CONST (0), 1, 0, 0);
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. */
576 #if 0 /* We need to eliminate regs even if there is no rtl code,
577 for the sake of debugging information. */
578 if (n_basic_blocks > 0)
580 return reload (get_insns (), 1, file);
583 /* Sort predicate for ordering the allocnos.
584 Returns -1 (1) if *v1 should be allocated before (after) *v2. */
587 allocno_compare (v1, v2)
590 /* Note that the quotient will never be bigger than
591 the value of floor_log2 times the maximum number of
592 times a register can occur in one insn (surely less than 100).
593 Multiplying this by 10000 can't overflow. */
595 = (((double) (floor_log2 (allocno_n_refs[*v1]) * allocno_n_refs[*v1])
596 / allocno_live_length[*v1])
597 * 10000 * allocno_size[*v1]);
599 = (((double) (floor_log2 (allocno_n_refs[*v2]) * allocno_n_refs[*v2])
600 / allocno_live_length[*v2])
601 * 10000 * allocno_size[*v2]);
605 /* If regs are equally good, sort by allocno,
606 so that the results of qsort leave nothing to chance. */
610 /* Scan the rtl code and record all conflicts and register preferences in the
611 conflict matrices and preference tables. */
618 short *block_start_allocnos;
620 /* Make a vector that mark_reg_{store,clobber} will store in. */
621 regs_set = (rtx *) alloca (max_parallel * sizeof (rtx) * 2);
623 block_start_allocnos = (short *) alloca (max_allocno * sizeof (short));
625 for (b = 0; b < n_basic_blocks; b++)
627 bzero ((char *) allocnos_live, allocno_row_words * sizeof (INT_TYPE));
629 /* Initialize table of registers currently live
630 to the state at the beginning of this basic block.
631 This also marks the conflicts among them.
633 For pseudo-regs, there is only one bit for each one
634 no matter how many hard regs it occupies.
635 This is ok; we know the size from PSEUDO_REGNO_SIZE.
636 For explicit hard regs, we cannot know the size that way
637 since one hard reg can be used with various sizes.
638 Therefore, we must require that all the hard regs
639 implicitly live as part of a multi-word hard reg
640 are explicitly marked in basic_block_live_at_start. */
645 register regset old = basic_block_live_at_start[b];
649 hard_regs_live = old[0];
651 COPY_HARD_REG_SET (hard_regs_live, old);
653 for (offset = 0, i = 0; offset < regset_size; offset++)
654 if (old[offset] == 0)
655 i += REGSET_ELT_BITS;
657 for (bit = 1; bit; bit <<= 1, i++)
661 if (old[offset] & bit)
663 register int a = reg_allocno[i];
666 SET_ALLOCNO_LIVE (a);
667 block_start_allocnos[ax++] = a;
669 else if ((a = reg_renumber[i]) >= 0)
670 mark_reg_live_nc (a, PSEUDO_REGNO_MODE (i));
674 /* Record that each allocno now live conflicts with each other
675 allocno now live, and with each hard reg now live. */
677 record_conflicts (block_start_allocnos, ax);
680 insn = basic_block_head[b];
682 /* Scan the code of this basic block, noting which allocnos
683 and hard regs are born or die. When one is born,
684 record a conflict with all others currently live. */
688 register RTX_CODE code = GET_CODE (insn);
691 /* Make regs_set an empty set. */
695 if (code == INSN || code == CALL_INSN || code == JUMP_INSN)
700 for (link = REG_NOTES (insn);
701 link && i < NUM_NO_CONFLICT_PAIRS;
702 link = XEXP (link, 1))
703 if (REG_NOTE_KIND (link) == REG_NO_CONFLICT)
705 no_conflict_pairs[i].allocno1
706 = reg_allocno[REGNO (SET_DEST (PATTERN (insn)))];
707 no_conflict_pairs[i].allocno2
708 = reg_allocno[REGNO (XEXP (link, 0))];
713 /* Mark any registers clobbered by INSN as live,
714 so they conflict with the inputs. */
716 note_stores (PATTERN (insn), mark_reg_clobber);
718 /* Mark any registers dead after INSN as dead now. */
720 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
721 if (REG_NOTE_KIND (link) == REG_DEAD)
722 mark_reg_death (XEXP (link, 0));
724 /* Mark any registers set in INSN as live,
725 and mark them as conflicting with all other live regs.
726 Clobbers are processed again, so they conflict with
727 the registers that are set. */
729 note_stores (PATTERN (insn), mark_reg_store);
732 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
733 if (REG_NOTE_KIND (link) == REG_INC)
734 mark_reg_store (XEXP (link, 0), NULL_RTX);
737 /* If INSN has multiple outputs, then any reg that dies here
738 and is used inside of an output
739 must conflict with the other outputs. */
741 if (GET_CODE (PATTERN (insn)) == PARALLEL && !single_set (insn))
742 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
743 if (REG_NOTE_KIND (link) == REG_DEAD)
745 int used_in_output = 0;
747 rtx reg = XEXP (link, 0);
749 for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
751 rtx set = XVECEXP (PATTERN (insn), 0, i);
752 if (GET_CODE (set) == SET
753 && GET_CODE (SET_DEST (set)) != REG
754 && !rtx_equal_p (reg, SET_DEST (set))
755 && reg_overlap_mentioned_p (reg, SET_DEST (set)))
759 mark_reg_conflicts (reg);
762 /* Mark any registers set in INSN and then never used. */
764 while (n_regs_set > 0)
765 if (find_regno_note (insn, REG_UNUSED,
766 REGNO (regs_set[--n_regs_set])))
767 mark_reg_death (regs_set[n_regs_set]);
770 if (insn == basic_block_end[b])
772 insn = NEXT_INSN (insn);
776 /* Expand the preference information by looking for cases where one allocno
777 dies in an insn that sets an allocno. If those two allocnos don't conflict,
778 merge any preferences between those allocnos. */
781 expand_preferences ()
787 /* We only try to handle the most common cases here. Most of the cases
788 where this wins are reg-reg copies. */
790 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
791 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
792 && (set = single_set (insn)) != 0
793 && GET_CODE (SET_DEST (set)) == REG
794 && reg_allocno[REGNO (SET_DEST (set))] >= 0)
795 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
796 if (REG_NOTE_KIND (link) == REG_DEAD
797 && GET_CODE (XEXP (link, 0)) == REG
798 && reg_allocno[REGNO (XEXP (link, 0))] >= 0
799 && ! CONFLICTP (reg_allocno[REGNO (SET_DEST (set))],
800 reg_allocno[REGNO (XEXP (link, 0))])
801 && ! CONFLICTP (reg_allocno[REGNO (XEXP (link, 0))],
802 reg_allocno[REGNO (SET_DEST (set))]))
804 int a1 = reg_allocno[REGNO (SET_DEST (set))];
805 int a2 = reg_allocno[REGNO (XEXP (link, 0))];
807 if (XEXP (link, 0) == SET_SRC (set))
809 IOR_HARD_REG_SET (hard_reg_copy_preferences[a1],
810 hard_reg_copy_preferences[a2]);
811 IOR_HARD_REG_SET (hard_reg_copy_preferences[a2],
812 hard_reg_copy_preferences[a1]);
815 IOR_HARD_REG_SET (hard_reg_preferences[a1],
816 hard_reg_preferences[a2]);
817 IOR_HARD_REG_SET (hard_reg_preferences[a2],
818 hard_reg_preferences[a1]);
819 IOR_HARD_REG_SET (hard_reg_full_preferences[a1],
820 hard_reg_full_preferences[a2]);
821 IOR_HARD_REG_SET (hard_reg_full_preferences[a2],
822 hard_reg_full_preferences[a1]);
826 /* Prune the preferences for global registers to exclude registers that cannot
829 Compute `regs_someone_prefers', which is a bitmask of the hard registers
830 that are preferred by conflicting registers of lower priority. If possible,
831 we will avoid using these registers. */
839 /* Scan least most important to most important.
840 For each allocno, remove from preferences registers that cannot be used,
841 either because of conflicts or register type. Then compute all registers
842 preferred by each lower-priority register that conflicts. */
844 for (i = max_allocno - 1; i >= 0; i--)
848 allocno = allocno_order[i];
849 COPY_HARD_REG_SET (temp, hard_reg_conflicts[allocno]);
851 if (allocno_calls_crossed[allocno] == 0)
852 IOR_HARD_REG_SET (temp, fixed_reg_set);
854 IOR_HARD_REG_SET (temp, call_used_reg_set);
856 IOR_COMPL_HARD_REG_SET
858 reg_class_contents[(int) reg_preferred_class (allocno_reg[allocno])]);
860 AND_COMPL_HARD_REG_SET (hard_reg_preferences[allocno], temp);
861 AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[allocno], temp);
862 AND_COMPL_HARD_REG_SET (hard_reg_full_preferences[allocno], temp);
864 CLEAR_HARD_REG_SET (regs_someone_prefers[allocno]);
866 /* Merge in the preferences of lower-priority registers (they have
867 already been pruned). If we also prefer some of those registers,
868 don't exclude them unless we are of a smaller size (in which case
869 we want to give the lower-priority allocno the first chance for
871 for (j = i + 1; j < max_allocno; j++)
872 if (CONFLICTP (allocno, allocno_order[j]))
874 COPY_HARD_REG_SET (temp,
875 hard_reg_full_preferences[allocno_order[j]]);
876 if (allocno_size[allocno_order[j]] <= allocno_size[allocno])
877 AND_COMPL_HARD_REG_SET (temp,
878 hard_reg_full_preferences[allocno]);
880 IOR_HARD_REG_SET (regs_someone_prefers[allocno], temp);
885 /* Assign a hard register to ALLOCNO; look for one that is the beginning
886 of a long enough stretch of hard regs none of which conflicts with ALLOCNO.
887 The registers marked in PREFREGS are tried first.
889 LOSERS, if non-zero, is a HARD_REG_SET indicating registers that cannot
890 be used for this allocation.
892 If ALT_REGS_P is zero, consider only the preferred class of ALLOCNO's reg.
893 Otherwise ignore that preferred class and use the alternate class.
895 If ACCEPT_CALL_CLOBBERED is nonzero, accept a call-clobbered hard reg that
896 will have to be saved and restored at calls.
898 RETRYING is nonzero if this is called from retry_global_alloc.
900 If we find one, record it in reg_renumber.
901 If not, do nothing. */
904 find_reg (allocno, losers, alt_regs_p, accept_call_clobbered, retrying)
908 int accept_call_clobbered;
911 register int i, best_reg, pass;
913 register /* Declare it register if it's a scalar. */
915 HARD_REG_SET used, used1, used2;
917 enum reg_class class = (alt_regs_p
918 ? reg_alternate_class (allocno_reg[allocno])
919 : reg_preferred_class (allocno_reg[allocno]));
920 enum machine_mode mode = PSEUDO_REGNO_MODE (allocno_reg[allocno]);
922 if (accept_call_clobbered)
923 COPY_HARD_REG_SET (used1, call_fixed_reg_set);
924 else if (allocno_calls_crossed[allocno] == 0)
925 COPY_HARD_REG_SET (used1, fixed_reg_set);
927 COPY_HARD_REG_SET (used1, call_used_reg_set);
929 /* Some registers should not be allocated in global-alloc. */
930 IOR_HARD_REG_SET (used1, no_global_alloc_regs);
932 IOR_HARD_REG_SET (used1, losers);
934 IOR_COMPL_HARD_REG_SET (used1, reg_class_contents[(int) class]);
935 COPY_HARD_REG_SET (used2, used1);
937 IOR_HARD_REG_SET (used1, hard_reg_conflicts[allocno]);
939 #ifdef CLASS_CANNOT_CHANGE_SIZE
940 if (reg_changes_size[allocno_reg[allocno]])
941 IOR_HARD_REG_SET (used1,
942 reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE]);
945 /* Try each hard reg to see if it fits. Do this in two passes.
946 In the first pass, skip registers that are preferred by some other pseudo
947 to give it a better chance of getting one of those registers. Only if
948 we can't get a register when excluding those do we take one of them.
949 However, we never allocate a register for the first time in pass 0. */
951 COPY_HARD_REG_SET (used, used1);
952 IOR_COMPL_HARD_REG_SET (used, regs_used_so_far);
953 IOR_HARD_REG_SET (used, regs_someone_prefers[allocno]);
956 for (i = FIRST_PSEUDO_REGISTER, pass = 0;
957 pass <= 1 && i >= FIRST_PSEUDO_REGISTER;
961 COPY_HARD_REG_SET (used, used1);
962 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
964 #ifdef REG_ALLOC_ORDER
965 int regno = reg_alloc_order[i];
969 if (! TEST_HARD_REG_BIT (used, regno)
970 && HARD_REGNO_MODE_OK (regno, mode))
973 register int lim = regno + HARD_REGNO_NREGS (regno, mode);
976 && ! TEST_HARD_REG_BIT (used, j));
983 #ifndef REG_ALLOC_ORDER
984 i = j; /* Skip starting points we know will lose */
990 /* See if there is a preferred register with the same class as the register
991 we allocated above. Making this restriction prevents register
992 preferencing from creating worse register allocation.
994 Remove from the preferred registers and conflicting registers. Note that
995 additional conflicts may have been added after `prune_preferences' was
998 First do this for those register with copy preferences, then all
999 preferred registers. */
1001 AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[allocno], used);
1002 GO_IF_HARD_REG_SUBSET (hard_reg_copy_preferences[allocno],
1003 reg_class_contents[(int) NO_REGS], no_copy_prefs);
1007 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1008 if (TEST_HARD_REG_BIT (hard_reg_copy_preferences[allocno], i)
1009 && HARD_REGNO_MODE_OK (i, mode)
1010 && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg)
1011 || reg_class_subset_p (REGNO_REG_CLASS (i),
1012 REGNO_REG_CLASS (best_reg))
1013 || reg_class_subset_p (REGNO_REG_CLASS (best_reg),
1014 REGNO_REG_CLASS (i))))
1017 register int lim = i + HARD_REGNO_NREGS (i, mode);
1020 && ! TEST_HARD_REG_BIT (used, j)
1021 && (REGNO_REG_CLASS (j)
1022 == REGNO_REG_CLASS (best_reg + (j - i))
1023 || reg_class_subset_p (REGNO_REG_CLASS (j),
1024 REGNO_REG_CLASS (best_reg + (j - i)))
1025 || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)),
1026 REGNO_REG_CLASS (j))));
1037 AND_COMPL_HARD_REG_SET (hard_reg_preferences[allocno], used);
1038 GO_IF_HARD_REG_SUBSET (hard_reg_preferences[allocno],
1039 reg_class_contents[(int) NO_REGS], no_prefs);
1043 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1044 if (TEST_HARD_REG_BIT (hard_reg_preferences[allocno], i)
1045 && HARD_REGNO_MODE_OK (i, mode)
1046 && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg)
1047 || reg_class_subset_p (REGNO_REG_CLASS (i),
1048 REGNO_REG_CLASS (best_reg))
1049 || reg_class_subset_p (REGNO_REG_CLASS (best_reg),
1050 REGNO_REG_CLASS (i))))
1053 register int lim = i + HARD_REGNO_NREGS (i, mode);
1056 && ! TEST_HARD_REG_BIT (used, j)
1057 && (REGNO_REG_CLASS (j)
1058 == REGNO_REG_CLASS (best_reg + (j - i))
1059 || reg_class_subset_p (REGNO_REG_CLASS (j),
1060 REGNO_REG_CLASS (best_reg + (j - i)))
1061 || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)),
1062 REGNO_REG_CLASS (j))));
1073 /* If we haven't succeeded yet, try with caller-saves.
1074 We need not check to see if the current function has nonlocal
1075 labels because we don't put any pseudos that are live over calls in
1076 registers in that case. */
1078 if (flag_caller_saves && best_reg < 0)
1080 /* Did not find a register. If it would be profitable to
1081 allocate a call-clobbered register and save and restore it
1082 around calls, do that. */
1083 if (! accept_call_clobbered
1084 && allocno_calls_crossed[allocno] != 0
1085 && CALLER_SAVE_PROFITABLE (allocno_n_refs[allocno],
1086 allocno_calls_crossed[allocno]))
1088 find_reg (allocno, losers, alt_regs_p, 1, retrying);
1089 if (reg_renumber[allocno_reg[allocno]] >= 0)
1091 caller_save_needed = 1;
1097 /* If we haven't succeeded yet,
1098 see if some hard reg that conflicts with us
1099 was utilized poorly by local-alloc.
1100 If so, kick out the regs that were put there by local-alloc
1101 so we can use it instead. */
1102 if (best_reg < 0 && !retrying
1103 /* Let's not bother with multi-reg allocnos. */
1104 && allocno_size[allocno] == 1)
1106 /* Count from the end, to find the least-used ones first. */
1107 for (i = FIRST_PSEUDO_REGISTER - 1; i >= 0; i--)
1109 #ifdef REG_ALLOC_ORDER
1110 int regno = reg_alloc_order[i];
1115 if (local_reg_n_refs[regno] != 0
1116 /* Don't use a reg no good for this pseudo. */
1117 && ! TEST_HARD_REG_BIT (used2, regno)
1118 && HARD_REGNO_MODE_OK (regno, mode)
1119 #ifdef CLASS_CANNOT_CHANGE_SIZE
1120 && ! (reg_changes_size[allocno_reg[allocno]]
1121 && (TEST_HARD_REG_BIT
1122 (reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE],
1127 /* We explicitly evaluate the divide results into temporary
1128 variables so as to avoid excess precision problems that occur
1129 on a i386-unknown-sysv4.2 (unixware) host. */
1131 double tmp1 = ((double) local_reg_n_refs[regno]
1132 / local_reg_live_length[regno]);
1133 double tmp2 = ((double) allocno_n_refs[allocno]
1134 / allocno_live_length[allocno]);
1138 /* Hard reg REGNO was used less in total by local regs
1139 than it would be used by this one allocno! */
1141 for (k = 0; k < max_regno; k++)
1142 if (reg_renumber[k] >= 0)
1144 int r = reg_renumber[k];
1146 = r + HARD_REGNO_NREGS (r, PSEUDO_REGNO_MODE (k));
1148 if (regno >= r && regno < endregno)
1149 reg_renumber[k] = -1;
1159 /* Did we find a register? */
1163 register int lim, j;
1164 HARD_REG_SET this_reg;
1166 /* Yes. Record it as the hard register of this pseudo-reg. */
1167 reg_renumber[allocno_reg[allocno]] = best_reg;
1168 /* Also of any pseudo-regs that share with it. */
1169 if (reg_may_share[allocno_reg[allocno]])
1170 for (j = FIRST_PSEUDO_REGISTER; j < max_regno; j++)
1171 if (reg_allocno[j] == allocno)
1172 reg_renumber[j] = best_reg;
1174 /* Make a set of the hard regs being allocated. */
1175 CLEAR_HARD_REG_SET (this_reg);
1176 lim = best_reg + HARD_REGNO_NREGS (best_reg, mode);
1177 for (j = best_reg; j < lim; j++)
1179 SET_HARD_REG_BIT (this_reg, j);
1180 SET_HARD_REG_BIT (regs_used_so_far, j);
1181 /* This is no longer a reg used just by local regs. */
1182 local_reg_n_refs[j] = 0;
1184 /* For each other pseudo-reg conflicting with this one,
1185 mark it as conflicting with the hard regs this one occupies. */
1187 for (j = 0; j < max_allocno; j++)
1188 if (CONFLICTP (lim, j) || CONFLICTP (j, lim))
1190 IOR_HARD_REG_SET (hard_reg_conflicts[j], this_reg);
1195 /* Called from `reload' to look for a hard reg to put pseudo reg REGNO in.
1196 Perhaps it had previously seemed not worth a hard reg,
1197 or perhaps its old hard reg has been commandeered for reloads.
1198 FORBIDDEN_REGS indicates certain hard regs that may not be used, even if
1199 they do not appear to be allocated.
1200 If FORBIDDEN_REGS is zero, no regs are forbidden. */
1203 retry_global_alloc (regno, forbidden_regs)
1205 HARD_REG_SET forbidden_regs;
1207 int allocno = reg_allocno[regno];
1210 /* If we have more than one register class,
1211 first try allocating in the class that is cheapest
1212 for this pseudo-reg. If that fails, try any reg. */
1213 if (N_REG_CLASSES > 1)
1214 find_reg (allocno, forbidden_regs, 0, 0, 1);
1215 if (reg_renumber[regno] < 0
1216 && reg_alternate_class (regno) != NO_REGS)
1217 find_reg (allocno, forbidden_regs, 1, 0, 1);
1219 /* If we found a register, modify the RTL for the register to
1220 show the hard register, and mark that register live. */
1221 if (reg_renumber[regno] >= 0)
1223 REGNO (regno_reg_rtx[regno]) = reg_renumber[regno];
1224 mark_home_live (regno);
1229 /* Record a conflict between register REGNO
1230 and everything currently live.
1231 REGNO must not be a pseudo reg that was allocated
1232 by local_alloc; such numbers must be translated through
1233 reg_renumber before calling here. */
1236 record_one_conflict (regno)
1241 if (regno < FIRST_PSEUDO_REGISTER)
1242 /* When a hard register becomes live,
1243 record conflicts with live pseudo regs. */
1244 for (j = 0; j < max_allocno; j++)
1246 if (ALLOCNO_LIVE_P (j))
1247 SET_HARD_REG_BIT (hard_reg_conflicts[j], regno);
1250 /* When a pseudo-register becomes live,
1251 record conflicts first with hard regs,
1252 then with other pseudo regs. */
1254 register int ialloc = reg_allocno[regno];
1255 register int ialloc_prod = ialloc * allocno_row_words;
1256 IOR_HARD_REG_SET (hard_reg_conflicts[ialloc], hard_regs_live);
1257 for (j = allocno_row_words - 1; j >= 0; j--)
1261 for (k = 0; k < n_no_conflict_pairs; k++)
1262 if (! ((j == no_conflict_pairs[k].allocno1
1263 && ialloc == no_conflict_pairs[k].allocno2)
1265 (j == no_conflict_pairs[k].allocno2
1266 && ialloc == no_conflict_pairs[k].allocno1)))
1268 conflicts[ialloc_prod + j] |= allocnos_live[j];
1273 /* Record all allocnos currently live as conflicting
1274 with each other and with all hard regs currently live.
1275 ALLOCNO_VEC is a vector of LEN allocnos, all allocnos that
1276 are currently live. Their bits are also flagged in allocnos_live. */
1279 record_conflicts (allocno_vec, len)
1280 register short *allocno_vec;
1283 register int allocno;
1285 register int ialloc_prod;
1289 allocno = allocno_vec[len];
1290 ialloc_prod = allocno * allocno_row_words;
1291 IOR_HARD_REG_SET (hard_reg_conflicts[allocno], hard_regs_live);
1292 for (j = allocno_row_words - 1; j >= 0; j--)
1293 conflicts[ialloc_prod + j] |= allocnos_live[j];
1297 /* Handle the case where REG is set by the insn being scanned,
1298 during the forward scan to accumulate conflicts.
1299 Store a 1 in regs_live or allocnos_live for this register, record how many
1300 consecutive hardware registers it actually needs,
1301 and record a conflict with all other registers already live.
1303 Note that even if REG does not remain alive after this insn,
1304 we must mark it here as live, to ensure a conflict between
1305 REG and any other regs set in this insn that really do live.
1306 This is because those other regs could be considered after this.
1308 REG might actually be something other than a register;
1309 if so, we do nothing.
1311 SETTER is 0 if this register was modified by an auto-increment (i.e.,
1312 a REG_INC note was found for it).
1314 CLOBBERs are processed here by calling mark_reg_clobber. */
1317 mark_reg_store (orig_reg, setter)
1318 rtx orig_reg, setter;
1321 register rtx reg = orig_reg;
1323 /* WORD is which word of a multi-register group is being stored.
1324 For the case where the store is actually into a SUBREG of REG.
1325 Except we don't use it; I believe the entire REG needs to be
1329 if (GET_CODE (reg) == SUBREG)
1331 word = SUBREG_WORD (reg);
1332 reg = SUBREG_REG (reg);
1335 if (GET_CODE (reg) != REG)
1338 if (setter && GET_CODE (setter) == CLOBBER)
1340 /* A clobber of a register should be processed here too. */
1341 mark_reg_clobber (orig_reg, setter);
1345 regs_set[n_regs_set++] = reg;
1348 set_preference (reg, SET_SRC (setter));
1350 regno = REGNO (reg);
1352 if (reg_renumber[regno] >= 0)
1353 regno = reg_renumber[regno] /* + word */;
1355 /* Either this is one of the max_allocno pseudo regs not allocated,
1356 or it is or has a hardware reg. First handle the pseudo-regs. */
1357 if (regno >= FIRST_PSEUDO_REGISTER)
1359 if (reg_allocno[regno] >= 0)
1361 SET_ALLOCNO_LIVE (reg_allocno[regno]);
1362 record_one_conflict (regno);
1365 /* Handle hardware regs (and pseudos allocated to hard regs). */
1366 else if (! fixed_regs[regno])
1368 register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
1369 while (regno < last)
1371 record_one_conflict (regno);
1372 SET_HARD_REG_BIT (hard_regs_live, regno);
1378 /* Like mark_reg_set except notice just CLOBBERs; ignore SETs. */
1381 mark_reg_clobber (reg, setter)
1386 /* WORD is which word of a multi-register group is being stored.
1387 For the case where the store is actually into a SUBREG of REG.
1388 Except we don't use it; I believe the entire REG needs to be
1392 if (GET_CODE (setter) != CLOBBER)
1395 if (GET_CODE (reg) == SUBREG)
1397 word = SUBREG_WORD (reg);
1398 reg = SUBREG_REG (reg);
1401 if (GET_CODE (reg) != REG)
1404 regs_set[n_regs_set++] = reg;
1406 regno = REGNO (reg);
1408 if (reg_renumber[regno] >= 0)
1409 regno = reg_renumber[regno] /* + word */;
1411 /* Either this is one of the max_allocno pseudo regs not allocated,
1412 or it is or has a hardware reg. First handle the pseudo-regs. */
1413 if (regno >= FIRST_PSEUDO_REGISTER)
1415 if (reg_allocno[regno] >= 0)
1417 SET_ALLOCNO_LIVE (reg_allocno[regno]);
1418 record_one_conflict (regno);
1421 /* Handle hardware regs (and pseudos allocated to hard regs). */
1422 else if (! fixed_regs[regno])
1424 register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
1425 while (regno < last)
1427 record_one_conflict (regno);
1428 SET_HARD_REG_BIT (hard_regs_live, regno);
1434 /* Record that REG has conflicts with all the regs currently live.
1435 Do not mark REG itself as live. */
1438 mark_reg_conflicts (reg)
1443 if (GET_CODE (reg) == SUBREG)
1444 reg = SUBREG_REG (reg);
1446 if (GET_CODE (reg) != REG)
1449 regno = REGNO (reg);
1451 if (reg_renumber[regno] >= 0)
1452 regno = reg_renumber[regno];
1454 /* Either this is one of the max_allocno pseudo regs not allocated,
1455 or it is or has a hardware reg. First handle the pseudo-regs. */
1456 if (regno >= FIRST_PSEUDO_REGISTER)
1458 if (reg_allocno[regno] >= 0)
1459 record_one_conflict (regno);
1461 /* Handle hardware regs (and pseudos allocated to hard regs). */
1462 else if (! fixed_regs[regno])
1464 register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
1465 while (regno < last)
1467 record_one_conflict (regno);
1473 /* Mark REG as being dead (following the insn being scanned now).
1474 Store a 0 in regs_live or allocnos_live for this register. */
1477 mark_reg_death (reg)
1480 register int regno = REGNO (reg);
1482 /* For pseudo reg, see if it has been assigned a hardware reg. */
1483 if (reg_renumber[regno] >= 0)
1484 regno = reg_renumber[regno];
1486 /* Either this is one of the max_allocno pseudo regs not allocated,
1487 or it is a hardware reg. First handle the pseudo-regs. */
1488 if (regno >= FIRST_PSEUDO_REGISTER)
1490 if (reg_allocno[regno] >= 0)
1491 CLEAR_ALLOCNO_LIVE (reg_allocno[regno]);
1493 /* Handle hardware regs (and pseudos allocated to hard regs). */
1494 else if (! fixed_regs[regno])
1496 /* Pseudo regs already assigned hardware regs are treated
1497 almost the same as explicit hardware regs. */
1498 register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
1499 while (regno < last)
1501 CLEAR_HARD_REG_BIT (hard_regs_live, regno);
1507 /* Mark hard reg REGNO as currently live, assuming machine mode MODE
1508 for the value stored in it. MODE determines how many consecutive
1509 registers are actually in use. Do not record conflicts;
1510 it is assumed that the caller will do that. */
1513 mark_reg_live_nc (regno, mode)
1515 enum machine_mode mode;
1517 register int last = regno + HARD_REGNO_NREGS (regno, mode);
1518 while (regno < last)
1520 SET_HARD_REG_BIT (hard_regs_live, regno);
1525 /* Try to set a preference for an allocno to a hard register.
1526 We are passed DEST and SRC which are the operands of a SET. It is known
1527 that SRC is a register. If SRC or the first operand of SRC is a register,
1528 try to set a preference. If one of the two is a hard register and the other
1529 is a pseudo-register, mark the preference.
1531 Note that we are not as aggressive as local-alloc in trying to tie a
1532 pseudo-register to a hard register. */
1535 set_preference (dest, src)
1538 int src_regno, dest_regno;
1539 /* Amount to add to the hard regno for SRC, or subtract from that for DEST,
1540 to compensate for subregs in SRC or DEST. */
1545 if (GET_RTX_FORMAT (GET_CODE (src))[0] == 'e')
1546 src = XEXP (src, 0), copy = 0;
1548 /* Get the reg number for both SRC and DEST.
1549 If neither is a reg, give up. */
1551 if (GET_CODE (src) == REG)
1552 src_regno = REGNO (src);
1553 else if (GET_CODE (src) == SUBREG && GET_CODE (SUBREG_REG (src)) == REG)
1555 src_regno = REGNO (SUBREG_REG (src));
1556 offset += SUBREG_WORD (src);
1561 if (GET_CODE (dest) == REG)
1562 dest_regno = REGNO (dest);
1563 else if (GET_CODE (dest) == SUBREG && GET_CODE (SUBREG_REG (dest)) == REG)
1565 dest_regno = REGNO (SUBREG_REG (dest));
1566 offset -= SUBREG_WORD (dest);
1571 /* Convert either or both to hard reg numbers. */
1573 if (reg_renumber[src_regno] >= 0)
1574 src_regno = reg_renumber[src_regno];
1576 if (reg_renumber[dest_regno] >= 0)
1577 dest_regno = reg_renumber[dest_regno];
1579 /* Now if one is a hard reg and the other is a global pseudo
1580 then give the other a preference. */
1582 if (dest_regno < FIRST_PSEUDO_REGISTER && src_regno >= FIRST_PSEUDO_REGISTER
1583 && reg_allocno[src_regno] >= 0)
1585 dest_regno -= offset;
1586 if (dest_regno >= 0 && dest_regno < FIRST_PSEUDO_REGISTER)
1589 SET_REGBIT (hard_reg_copy_preferences,
1590 reg_allocno[src_regno], dest_regno);
1592 SET_REGBIT (hard_reg_preferences,
1593 reg_allocno[src_regno], dest_regno);
1594 for (i = dest_regno;
1595 i < dest_regno + HARD_REGNO_NREGS (dest_regno, GET_MODE (dest));
1597 SET_REGBIT (hard_reg_full_preferences, reg_allocno[src_regno], i);
1601 if (src_regno < FIRST_PSEUDO_REGISTER && dest_regno >= FIRST_PSEUDO_REGISTER
1602 && reg_allocno[dest_regno] >= 0)
1604 src_regno += offset;
1605 if (src_regno >= 0 && src_regno < FIRST_PSEUDO_REGISTER)
1608 SET_REGBIT (hard_reg_copy_preferences,
1609 reg_allocno[dest_regno], src_regno);
1611 SET_REGBIT (hard_reg_preferences,
1612 reg_allocno[dest_regno], src_regno);
1614 i < src_regno + HARD_REGNO_NREGS (src_regno, GET_MODE (src));
1616 SET_REGBIT (hard_reg_full_preferences, reg_allocno[dest_regno], i);
1621 /* Indicate that hard register number FROM was eliminated and replaced with
1622 an offset from hard register number TO. The status of hard registers live
1623 at the start of a basic block is updated by replacing a use of FROM with
1627 mark_elimination (from, to)
1632 for (i = 0; i < n_basic_blocks; i++)
1633 if ((basic_block_live_at_start[i][from / REGSET_ELT_BITS]
1634 & ((REGSET_ELT_TYPE) 1 << (from % REGSET_ELT_BITS))) != 0)
1636 basic_block_live_at_start[i][from / REGSET_ELT_BITS]
1637 &= ~ ((REGSET_ELT_TYPE) 1 << (from % REGSET_ELT_BITS));
1638 basic_block_live_at_start[i][to / REGSET_ELT_BITS]
1639 |= ((REGSET_ELT_TYPE) 1 << (to % REGSET_ELT_BITS));
1643 /* Print debugging trace information if -greg switch is given,
1644 showing the information on which the allocation decisions are based. */
1647 dump_conflicts (file)
1651 register int has_preferences;
1652 fprintf (file, ";; %d regs to allocate:", max_allocno);
1653 for (i = 0; i < max_allocno; i++)
1656 fprintf (file, " %d", allocno_reg[allocno_order[i]]);
1657 for (j = 0; j < max_regno; j++)
1658 if (reg_allocno[j] == allocno_order[i]
1659 && j != allocno_reg[allocno_order[i]])
1660 fprintf (file, "+%d", j);
1661 if (allocno_size[allocno_order[i]] != 1)
1662 fprintf (file, " (%d)", allocno_size[allocno_order[i]]);
1664 fprintf (file, "\n");
1666 for (i = 0; i < max_allocno; i++)
1669 fprintf (file, ";; %d conflicts:", allocno_reg[i]);
1670 for (j = 0; j < max_allocno; j++)
1671 if (CONFLICTP (i, j) || CONFLICTP (j, i))
1672 fprintf (file, " %d", allocno_reg[j]);
1673 for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
1674 if (TEST_HARD_REG_BIT (hard_reg_conflicts[i], j))
1675 fprintf (file, " %d", j);
1676 fprintf (file, "\n");
1678 has_preferences = 0;
1679 for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
1680 if (TEST_HARD_REG_BIT (hard_reg_preferences[i], j))
1681 has_preferences = 1;
1683 if (! has_preferences)
1685 fprintf (file, ";; %d preferences:", allocno_reg[i]);
1686 for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
1687 if (TEST_HARD_REG_BIT (hard_reg_preferences[i], j))
1688 fprintf (file, " %d", j);
1689 fprintf (file, "\n");
1691 fprintf (file, "\n");
1695 dump_global_regs (file)
1700 fprintf (file, ";; Register dispositions:\n");
1701 for (i = FIRST_PSEUDO_REGISTER, j = 0; i < max_regno; i++)
1702 if (reg_renumber[i] >= 0)
1704 fprintf (file, "%d in %d ", i, reg_renumber[i]);
1706 fprintf (file, "\n");
1709 fprintf (file, "\n\n;; Hard regs used: ");
1710 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1711 if (regs_ever_live[i])
1712 fprintf (file, " %d", i);
1713 fprintf (file, "\n\n");