1 /* Allocate registers for pseudo-registers that span basic blocks.
2 Copyright (C) 1987, 88, 91, 94, 96-98, 1999 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 "hard-reg-set.h"
30 #include "basic-block.h"
33 #include "insn-config.h"
38 /* This pass of the compiler performs global register allocation.
39 It assigns hard register numbers to all the pseudo registers
40 that were not handled in local_alloc. Assignments are recorded
41 in the vector reg_renumber, not by changing the rtl code.
42 (Such changes are made by final). The entry point is
43 the function global_alloc.
45 After allocation is complete, the reload pass is run as a subroutine
46 of this pass, so that when a pseudo reg loses its hard reg due to
47 spilling it is possible to make a second attempt to find a hard
48 reg for it. The reload pass is independent in other respects
49 and it is run even when stupid register allocation is in use.
51 1. Assign allocation-numbers (allocnos) to the pseudo-registers
52 still needing allocations and to the pseudo-registers currently
53 allocated by local-alloc which may be spilled by reload.
54 Set up tables reg_allocno and allocno_reg to map
55 reg numbers to allocnos and vice versa.
56 max_allocno gets the number of allocnos in use.
58 2. Allocate a max_allocno by max_allocno conflict bit matrix and clear it.
59 Allocate a max_allocno by FIRST_PSEUDO_REGISTER conflict matrix
60 for conflicts between allocnos and explicit hard register use
61 (which includes use of pseudo-registers allocated by local_alloc).
63 3. For each basic block
64 walk forward through the block, recording which
65 pseudo-registers and which hardware registers are live.
66 Build the conflict matrix between the pseudo-registers
67 and another of pseudo-registers versus hardware registers.
68 Also record the preferred hardware registers
69 for each pseudo-register.
71 4. Sort a table of the allocnos into order of
72 desirability of the variables.
74 5. Allocate the variables in that order; each if possible into
75 a preferred register, else into another register. */
77 /* Number of pseudo-registers which are candidates for allocation. */
79 static int max_allocno;
81 /* Indexed by (pseudo) reg number, gives the allocno, or -1
82 for pseudo registers which are not to be allocated. */
84 static int *reg_allocno;
89 /* Gives the number of consecutive hard registers needed by that
93 /* Number of calls crossed by each allocno. */
96 /* Number of refs (weighted) to each allocno. */
99 /* Guess at live length of each allocno.
100 This is actually the max of the live lengths of the regs. */
103 /* Set of hard regs conflicting with allocno N. */
105 HARD_REG_SET hard_reg_conflicts;
107 /* Set of hard regs preferred by allocno N.
108 This is used to make allocnos go into regs that are copied to or from them,
109 when possible, to reduce register shuffling. */
111 HARD_REG_SET hard_reg_preferences;
113 /* Similar, but just counts register preferences made in simple copy
114 operations, rather than arithmetic. These are given priority because
115 we can always eliminate an insn by using these, but using a register
116 in the above list won't always eliminate an insn. */
118 HARD_REG_SET hard_reg_copy_preferences;
120 /* Similar to hard_reg_preferences, but includes bits for subsequent
121 registers when an allocno is multi-word. The above variable is used for
122 allocation while this is used to build reg_someone_prefers, below. */
124 HARD_REG_SET hard_reg_full_preferences;
126 /* Set of hard registers that some later allocno has a preference for. */
128 HARD_REG_SET regs_someone_prefers;
131 static struct allocno *allocno;
133 /* A vector of the integers from 0 to max_allocno-1,
134 sorted in the order of first-to-be-allocated first. */
136 static int *allocno_order;
138 /* Indexed by (pseudo) reg number, gives the number of another
139 lower-numbered pseudo reg which can share a hard reg with this pseudo
140 *even if the two pseudos would otherwise appear to conflict*. */
142 static int *reg_may_share;
144 /* Define the number of bits in each element of `conflicts' and what
145 type that element has. We use the largest integer format on the
148 #define INT_BITS HOST_BITS_PER_WIDE_INT
149 #define INT_TYPE HOST_WIDE_INT
151 /* max_allocno by max_allocno array of bits,
152 recording whether two allocno's conflict (can't go in the same
155 `conflicts' is symmetric after the call to mirror_conflicts. */
157 static INT_TYPE *conflicts;
159 /* Number of ints require to hold max_allocno bits.
160 This is the length of a row in `conflicts'. */
162 static int allocno_row_words;
164 /* Two macros to test or store 1 in an element of `conflicts'. */
166 #define CONFLICTP(I, J) \
167 (conflicts[(I) * allocno_row_words + (unsigned)(J) / INT_BITS] \
168 & ((INT_TYPE) 1 << ((unsigned)(J) % INT_BITS)))
170 #define SET_CONFLICT(I, J) \
171 (conflicts[(I) * allocno_row_words + (unsigned)(J) / INT_BITS] \
172 |= ((INT_TYPE) 1 << ((unsigned)(J) % INT_BITS)))
174 /* For any allocno set in ALLOCNO_SET, set ALLOCNO to that allocno,
176 #define EXECUTE_IF_SET_IN_ALLOCNO_SET(ALLOCNO_SET, ALLOCNO, CODE) \
180 INT_TYPE *p_ = (ALLOCNO_SET); \
182 for (i_ = allocno_row_words - 1, allocno_ = 0; i_ >= 0; \
183 i_--, allocno_ += INT_BITS) \
185 unsigned INT_TYPE word_ = (unsigned INT_TYPE) *p_++; \
187 for ((ALLOCNO) = allocno_; word_; word_ >>= 1, (ALLOCNO)++) \
195 /* This doesn't work for non-GNU C due to the way CODE is macro expanded. */
197 /* For any allocno that conflicts with IN_ALLOCNO, set OUT_ALLOCNO to
198 the conflicting allocno, and execute CODE. This macro assumes that
199 mirror_conflicts has been run. */
200 #define EXECUTE_IF_CONFLICT(IN_ALLOCNO, OUT_ALLOCNO, CODE)\
201 EXECUTE_IF_SET_IN_ALLOCNO_SET (conflicts + (IN_ALLOCNO) * allocno_row_words,\
205 /* Set of hard regs currently live (during scan of all insns). */
207 static HARD_REG_SET hard_regs_live;
209 /* Set of registers that global-alloc isn't supposed to use. */
211 static HARD_REG_SET no_global_alloc_regs;
213 /* Set of registers used so far. */
215 static HARD_REG_SET regs_used_so_far;
217 /* Number of refs (weighted) to each hard reg, as used by local alloc.
218 It is zero for a reg that contains global pseudos or is explicitly used. */
220 static int local_reg_n_refs[FIRST_PSEUDO_REGISTER];
222 /* Guess at live length of each hard reg, as used by local alloc.
223 This is actually the sum of the live lengths of the specific regs. */
225 static int local_reg_live_length[FIRST_PSEUDO_REGISTER];
227 /* Test a bit in TABLE, a vector of HARD_REG_SETs,
228 for vector element I, and hard register number J. */
230 #define REGBITP(TABLE, I, J) TEST_HARD_REG_BIT (allocno[I].TABLE, J)
232 /* Set to 1 a bit in a vector of HARD_REG_SETs. Works like REGBITP. */
234 #define SET_REGBIT(TABLE, I, J) SET_HARD_REG_BIT (allocno[I].TABLE, J)
236 /* Bit mask for allocnos live at current point in the scan. */
238 static INT_TYPE *allocnos_live;
240 /* Test, set or clear bit number I in allocnos_live,
241 a bit vector indexed by allocno. */
243 #define ALLOCNO_LIVE_P(I) \
244 (allocnos_live[(unsigned)(I) / INT_BITS] \
245 & ((INT_TYPE) 1 << ((unsigned)(I) % INT_BITS)))
247 #define SET_ALLOCNO_LIVE(I) \
248 (allocnos_live[(unsigned)(I) / INT_BITS] \
249 |= ((INT_TYPE) 1 << ((unsigned)(I) % INT_BITS)))
251 #define CLEAR_ALLOCNO_LIVE(I) \
252 (allocnos_live[(unsigned)(I) / INT_BITS] \
253 &= ~((INT_TYPE) 1 << ((unsigned)(I) % INT_BITS)))
255 /* This is turned off because it doesn't work right for DImode.
256 (And it is only used for DImode, so the other cases are worthless.)
257 The problem is that it isn't true that there is NO possibility of conflict;
258 only that there is no conflict if the two pseudos get the exact same regs.
259 If they were allocated with a partial overlap, there would be a conflict.
260 We can't safely turn off the conflict unless we have another way to
261 prevent the partial overlap.
263 Idea: change hard_reg_conflicts so that instead of recording which
264 hard regs the allocno may not overlap, it records where the allocno
265 may not start. Change both where it is used and where it is updated.
266 Then there is a way to record that (reg:DI 108) may start at 10
267 but not at 9 or 11. There is still the question of how to record
268 this semi-conflict between two pseudos. */
270 /* Reg pairs for which conflict after the current insn
271 is inhibited by a REG_NO_CONFLICT note.
272 If the table gets full, we ignore any other notes--that is conservative. */
273 #define NUM_NO_CONFLICT_PAIRS 4
274 /* Number of pairs in use in this insn. */
275 int n_no_conflict_pairs;
276 static struct { int allocno1, allocno2;}
277 no_conflict_pairs[NUM_NO_CONFLICT_PAIRS];
280 /* Record all regs that are set in any one insn.
281 Communication from mark_reg_{store,clobber} and global_conflicts. */
283 static rtx *regs_set;
284 static int n_regs_set;
286 /* All registers that can be eliminated. */
288 static HARD_REG_SET eliminable_regset;
290 static int allocno_compare PROTO((const PTR, const PTR));
291 static void global_conflicts PROTO((void));
292 static void mirror_conflicts PROTO((void));
293 static void expand_preferences PROTO((void));
294 static void prune_preferences PROTO((void));
295 static void find_reg PROTO((int, HARD_REG_SET, int, int, int));
296 static void record_one_conflict PROTO((int));
297 static void record_conflicts PROTO((int *, int));
298 static void mark_reg_store PROTO((rtx, rtx, void *));
299 static void mark_reg_clobber PROTO((rtx, rtx, void *));
300 static void mark_reg_conflicts PROTO((rtx));
301 static void mark_reg_death PROTO((rtx));
302 static void mark_reg_live_nc PROTO((int, enum machine_mode));
303 static void set_preference PROTO((rtx, rtx));
304 static void dump_conflicts PROTO((FILE *));
305 static void reg_becomes_live PROTO((rtx, rtx, void *));
306 static void reg_dies PROTO((int, enum machine_mode));
307 static void build_insn_chain PROTO((rtx));
309 /* Perform allocation of pseudo-registers not allocated by local_alloc.
310 FILE is a file to output debugging information on,
311 or zero if such output is not desired.
313 Return value is nonzero if reload failed
314 and we must not do any more for this function. */
321 #ifdef ELIMINABLE_REGS
322 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
325 = (! flag_omit_frame_pointer
326 #ifdef EXIT_IGNORE_STACK
327 || (current_function_calls_alloca && EXIT_IGNORE_STACK)
329 || FRAME_POINTER_REQUIRED);
336 /* A machine may have certain hard registers that
337 are safe to use only within a basic block. */
339 CLEAR_HARD_REG_SET (no_global_alloc_regs);
341 /* Build the regset of all eliminable registers and show we can't use those
342 that we already know won't be eliminated. */
343 #ifdef ELIMINABLE_REGS
344 for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++)
346 SET_HARD_REG_BIT (eliminable_regset, eliminables[i].from);
348 if (! CAN_ELIMINATE (eliminables[i].from, eliminables[i].to)
349 || (eliminables[i].to == STACK_POINTER_REGNUM && need_fp))
350 SET_HARD_REG_BIT (no_global_alloc_regs, eliminables[i].from);
352 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
353 SET_HARD_REG_BIT (eliminable_regset, HARD_FRAME_POINTER_REGNUM);
355 SET_HARD_REG_BIT (no_global_alloc_regs, HARD_FRAME_POINTER_REGNUM);
359 SET_HARD_REG_BIT (eliminable_regset, FRAME_POINTER_REGNUM);
361 SET_HARD_REG_BIT (no_global_alloc_regs, FRAME_POINTER_REGNUM);
364 /* Track which registers have already been used. Start with registers
365 explicitly in the rtl, then registers allocated by local register
368 CLEAR_HARD_REG_SET (regs_used_so_far);
369 #ifdef LEAF_REGISTERS
370 /* If we are doing the leaf function optimization, and this is a leaf
371 function, it means that the registers that take work to save are those
372 that need a register window. So prefer the ones that can be used in
376 static char leaf_regs[] = LEAF_REGISTERS;
378 if (only_leaf_regs_used () && leaf_function_p ())
379 cheap_regs = leaf_regs;
381 cheap_regs = call_used_regs;
382 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
383 if (regs_ever_live[i] || cheap_regs[i])
384 SET_HARD_REG_BIT (regs_used_so_far, i);
387 /* We consider registers that do not have to be saved over calls as if
388 they were already used since there is no cost in using them. */
389 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
390 if (regs_ever_live[i] || call_used_regs[i])
391 SET_HARD_REG_BIT (regs_used_so_far, i);
394 for (i = FIRST_PSEUDO_REGISTER; i < (size_t) max_regno; i++)
395 if (reg_renumber[i] >= 0)
396 SET_HARD_REG_BIT (regs_used_so_far, reg_renumber[i]);
398 /* Establish mappings from register number to allocation number
399 and vice versa. In the process, count the allocnos. */
401 reg_allocno = (int *) xmalloc (max_regno * sizeof (int));
403 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
406 /* Initialize the shared-hard-reg mapping
407 from the list of pairs that may share. */
408 reg_may_share = (int *) xcalloc (max_regno, sizeof (int));
409 for (x = regs_may_share; x; x = XEXP (XEXP (x, 1), 1))
411 int r1 = REGNO (XEXP (x, 0));
412 int r2 = REGNO (XEXP (XEXP (x, 1), 0));
414 reg_may_share[r1] = r2;
416 reg_may_share[r2] = r1;
419 for (i = FIRST_PSEUDO_REGISTER; i < (size_t) max_regno; i++)
420 /* Note that reg_live_length[i] < 0 indicates a "constant" reg
421 that we are supposed to refrain from putting in a hard reg.
422 -2 means do make an allocno but don't allocate it. */
423 if (REG_N_REFS (i) != 0 && REG_LIVE_LENGTH (i) != -1
424 /* Don't allocate pseudos that cross calls,
425 if this function receives a nonlocal goto. */
426 && (! current_function_has_nonlocal_label
427 || REG_N_CALLS_CROSSED (i) == 0))
429 if (reg_renumber[i] < 0 && reg_may_share[i] && reg_allocno[reg_may_share[i]] >= 0)
430 reg_allocno[i] = reg_allocno[reg_may_share[i]];
432 reg_allocno[i] = max_allocno++;
433 if (REG_LIVE_LENGTH (i) == 0)
439 allocno = (struct allocno *) xcalloc (max_allocno, sizeof (struct allocno));
441 for (i = FIRST_PSEUDO_REGISTER; i < (size_t) max_regno; i++)
442 if (reg_allocno[i] >= 0)
444 int num = reg_allocno[i];
445 allocno[num].reg = i;
446 allocno[num].size = PSEUDO_REGNO_SIZE (i);
447 allocno[num].calls_crossed += REG_N_CALLS_CROSSED (i);
448 allocno[num].n_refs += REG_N_REFS (i);
449 if (allocno[num].live_length < REG_LIVE_LENGTH (i))
450 allocno[num].live_length = REG_LIVE_LENGTH (i);
453 /* Calculate amount of usage of each hard reg by pseudos
454 allocated by local-alloc. This is to see if we want to
456 bzero ((char *) local_reg_live_length, sizeof local_reg_live_length);
457 bzero ((char *) local_reg_n_refs, sizeof local_reg_n_refs);
458 for (i = FIRST_PSEUDO_REGISTER; i < (size_t) max_regno; i++)
459 if (reg_renumber[i] >= 0)
461 int regno = reg_renumber[i];
462 int endregno = regno + HARD_REGNO_NREGS (regno, PSEUDO_REGNO_MODE (i));
465 for (j = regno; j < endregno; j++)
467 local_reg_n_refs[j] += REG_N_REFS (i);
468 local_reg_live_length[j] += REG_LIVE_LENGTH (i);
472 /* We can't override local-alloc for a reg used not just by local-alloc. */
473 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
474 if (regs_ever_live[i])
475 local_reg_n_refs[i] = 0;
477 allocno_row_words = (max_allocno + INT_BITS - 1) / INT_BITS;
479 /* We used to use alloca here, but the size of what it would try to
480 allocate would occasionally cause it to exceed the stack limit and
481 cause unpredictable core dumps. Some examples were > 2Mb in size. */
482 conflicts = (INT_TYPE *) xcalloc (max_allocno * allocno_row_words,
485 allocnos_live = (INT_TYPE *) xmalloc (allocno_row_words * sizeof (INT_TYPE));
487 /* If there is work to be done (at least one reg to allocate),
488 perform global conflict analysis and allocate the regs. */
492 /* Scan all the insns and compute the conflicts among allocnos
493 and between allocnos and hard regs. */
499 /* Eliminate conflicts between pseudos and eliminable registers. If
500 the register is not eliminated, the pseudo won't really be able to
501 live in the eliminable register, so the conflict doesn't matter.
502 If we do eliminate the register, the conflict will no longer exist.
503 So in either case, we can ignore the conflict. Likewise for
506 for (i = 0; i < (size_t) max_allocno; i++)
508 AND_COMPL_HARD_REG_SET (allocno[i].hard_reg_conflicts,
510 AND_COMPL_HARD_REG_SET (allocno[i].hard_reg_copy_preferences,
512 AND_COMPL_HARD_REG_SET (allocno[i].hard_reg_preferences,
516 /* Try to expand the preferences by merging them between allocnos. */
518 expand_preferences ();
520 /* Determine the order to allocate the remaining pseudo registers. */
522 allocno_order = (int *) xmalloc (max_allocno * sizeof (int));
523 for (i = 0; i < (size_t) max_allocno; i++)
524 allocno_order[i] = i;
526 /* Default the size to 1, since allocno_compare uses it to divide by.
527 Also convert allocno_live_length of zero to -1. A length of zero
528 can occur when all the registers for that allocno have reg_live_length
529 equal to -2. In this case, we want to make an allocno, but not
530 allocate it. So avoid the divide-by-zero and set it to a low
533 for (i = 0; i < (size_t) max_allocno; i++)
535 if (allocno[i].size == 0)
537 if (allocno[i].live_length == 0)
538 allocno[i].live_length = -1;
541 qsort (allocno_order, max_allocno, sizeof (int), allocno_compare);
543 prune_preferences ();
546 dump_conflicts (file);
548 /* Try allocating them, one by one, in that order,
549 except for parameters marked with reg_live_length[regno] == -2. */
551 for (i = 0; i < (size_t) max_allocno; i++)
552 if (reg_renumber[allocno[allocno_order[i]].reg] < 0
553 && REG_LIVE_LENGTH (allocno[allocno_order[i]].reg) >= 0)
555 /* If we have more than one register class,
556 first try allocating in the class that is cheapest
557 for this pseudo-reg. If that fails, try any reg. */
558 if (N_REG_CLASSES > 1)
560 find_reg (allocno_order[i], 0, 0, 0, 0);
561 if (reg_renumber[allocno[allocno_order[i]].reg] >= 0)
564 if (reg_alternate_class (allocno[allocno_order[i]].reg) != NO_REGS)
565 find_reg (allocno_order[i], 0, 1, 0, 0);
568 free (allocno_order);
571 /* Do the reloads now while the allocno data still exist, so that we can
572 try to assign new hard regs to any pseudo regs that are spilled. */
574 #if 0 /* We need to eliminate regs even if there is no rtl code,
575 for the sake of debugging information. */
576 if (n_basic_blocks > 0)
579 build_insn_chain (get_insns ());
580 retval = reload (get_insns (), 1, file);
585 free (reg_may_share);
588 free (allocnos_live);
593 /* Sort predicate for ordering the allocnos.
594 Returns -1 (1) if *v1 should be allocated before (after) *v2. */
597 allocno_compare (v1p, v2p)
601 int v1 = *(const int *)v1p, v2 = *(const int *)v2p;
602 /* Note that the quotient will never be bigger than
603 the value of floor_log2 times the maximum number of
604 times a register can occur in one insn (surely less than 100).
605 Multiplying this by 10000 can't overflow. */
607 = (((double) (floor_log2 (allocno[v1].n_refs) * allocno[v1].n_refs)
608 / allocno[v1].live_length)
609 * 10000 * allocno[v1].size);
611 = (((double) (floor_log2 (allocno[v2].n_refs) * allocno[v2].n_refs)
612 / allocno[v2].live_length)
613 * 10000 * allocno[v2].size);
617 /* If regs are equally good, sort by allocno,
618 so that the results of qsort leave nothing to chance. */
622 /* Scan the rtl code and record all conflicts and register preferences in the
623 conflict matrices and preference tables. */
630 int *block_start_allocnos;
632 /* Make a vector that mark_reg_{store,clobber} will store in. */
633 regs_set = (rtx *) xmalloc (max_parallel * sizeof (rtx) * 2);
635 block_start_allocnos = (int *) xmalloc (max_allocno * sizeof (int));
637 for (b = 0; b < n_basic_blocks; b++)
639 bzero ((char *) allocnos_live, allocno_row_words * sizeof (INT_TYPE));
641 /* Initialize table of registers currently live
642 to the state at the beginning of this basic block.
643 This also marks the conflicts among hard registers
644 and any allocnos that are live.
646 For pseudo-regs, there is only one bit for each one
647 no matter how many hard regs it occupies.
648 This is ok; we know the size from PSEUDO_REGNO_SIZE.
649 For explicit hard regs, we cannot know the size that way
650 since one hard reg can be used with various sizes.
651 Therefore, we must require that all the hard regs
652 implicitly live as part of a multi-word hard reg
653 are explicitly marked in basic_block_live_at_start. */
656 register regset old = BASIC_BLOCK (b)->global_live_at_start;
659 REG_SET_TO_HARD_REG_SET (hard_regs_live, old);
660 EXECUTE_IF_SET_IN_REG_SET (old, FIRST_PSEUDO_REGISTER, i,
662 register int a = reg_allocno[i];
665 SET_ALLOCNO_LIVE (a);
666 block_start_allocnos[ax++] = a;
668 else if ((a = reg_renumber[i]) >= 0)
670 (a, PSEUDO_REGNO_MODE (i));
673 /* Record that each allocno now live conflicts with each hard reg
676 It is not necessary to mark any conflicts between pseudos as
677 this point, even for pseudos which are live at the start of
680 Given two pseudos X and Y and any point in the CFG P.
682 On any path to point P where X and Y are live one of the
683 following conditions must be true:
685 1. X is live at some instruction on the path that
688 2. Y is live at some instruction on the path that
691 3. Either X or Y is not evaluted on the path to P
692 (ie it is used uninitialized) and thus the
693 conflict can be ignored.
695 In cases #1 and #2 the conflict will be recorded when we
696 scan the instruction that makes either X or Y become live. */
697 record_conflicts (block_start_allocnos, ax);
701 /* Pseudos can't go in stack regs at the start of a basic block
702 that is reached by an abnormal edge. */
705 for (e = BASIC_BLOCK (b)->pred; e ; e = e->pred_next)
706 if (e->flags & EDGE_ABNORMAL)
709 for (ax = FIRST_STACK_REG; ax <= LAST_STACK_REG; ax++)
710 record_one_conflict (ax);
715 insn = BLOCK_HEAD (b);
717 /* Scan the code of this basic block, noting which allocnos
718 and hard regs are born or die. When one is born,
719 record a conflict with all others currently live. */
723 register RTX_CODE code = GET_CODE (insn);
726 /* Make regs_set an empty set. */
730 if (code == INSN || code == CALL_INSN || code == JUMP_INSN)
735 for (link = REG_NOTES (insn);
736 link && i < NUM_NO_CONFLICT_PAIRS;
737 link = XEXP (link, 1))
738 if (REG_NOTE_KIND (link) == REG_NO_CONFLICT)
740 no_conflict_pairs[i].allocno1
741 = reg_allocno[REGNO (SET_DEST (PATTERN (insn)))];
742 no_conflict_pairs[i].allocno2
743 = reg_allocno[REGNO (XEXP (link, 0))];
748 /* Mark any registers clobbered by INSN as live,
749 so they conflict with the inputs. */
751 note_stores (PATTERN (insn), mark_reg_clobber, NULL);
753 /* Mark any registers dead after INSN as dead now. */
755 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
756 if (REG_NOTE_KIND (link) == REG_DEAD)
757 mark_reg_death (XEXP (link, 0));
759 /* Mark any registers set in INSN as live,
760 and mark them as conflicting with all other live regs.
761 Clobbers are processed again, so they conflict with
762 the registers that are set. */
764 note_stores (PATTERN (insn), mark_reg_store, NULL);
767 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
768 if (REG_NOTE_KIND (link) == REG_INC)
769 mark_reg_store (XEXP (link, 0), NULL_RTX, NULL);
772 /* If INSN has multiple outputs, then any reg that dies here
773 and is used inside of an output
774 must conflict with the other outputs.
776 It is unsafe to use !single_set here since it will ignore an
777 unused output. Just because an output is unused does not mean
778 the compiler can assume the side effect will not occur.
779 Consider if REG appears in the address of an output and we
780 reload the output. If we allocate REG to the same hard
781 register as an unused output we could set the hard register
782 before the output reload insn. */
783 if (GET_CODE (PATTERN (insn)) == PARALLEL && multiple_sets (insn))
784 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
785 if (REG_NOTE_KIND (link) == REG_DEAD)
787 int used_in_output = 0;
789 rtx reg = XEXP (link, 0);
791 for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
793 rtx set = XVECEXP (PATTERN (insn), 0, i);
794 if (GET_CODE (set) == SET
795 && GET_CODE (SET_DEST (set)) != REG
796 && !rtx_equal_p (reg, SET_DEST (set))
797 && reg_overlap_mentioned_p (reg, SET_DEST (set)))
801 mark_reg_conflicts (reg);
804 /* Mark any registers set in INSN and then never used. */
806 while (n_regs_set > 0)
807 if (find_regno_note (insn, REG_UNUSED,
808 REGNO (regs_set[--n_regs_set])))
809 mark_reg_death (regs_set[n_regs_set]);
812 if (insn == BLOCK_END (b))
814 insn = NEXT_INSN (insn);
819 free (block_start_allocnos);
822 /* Expand the preference information by looking for cases where one allocno
823 dies in an insn that sets an allocno. If those two allocnos don't conflict,
824 merge any preferences between those allocnos. */
827 expand_preferences ()
833 /* We only try to handle the most common cases here. Most of the cases
834 where this wins are reg-reg copies. */
836 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
837 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
838 && (set = single_set (insn)) != 0
839 && GET_CODE (SET_DEST (set)) == REG
840 && reg_allocno[REGNO (SET_DEST (set))] >= 0)
841 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
842 if (REG_NOTE_KIND (link) == REG_DEAD
843 && GET_CODE (XEXP (link, 0)) == REG
844 && reg_allocno[REGNO (XEXP (link, 0))] >= 0
845 && ! CONFLICTP (reg_allocno[REGNO (SET_DEST (set))],
846 reg_allocno[REGNO (XEXP (link, 0))]))
848 int a1 = reg_allocno[REGNO (SET_DEST (set))];
849 int a2 = reg_allocno[REGNO (XEXP (link, 0))];
851 if (XEXP (link, 0) == SET_SRC (set))
853 IOR_HARD_REG_SET (allocno[a1].hard_reg_copy_preferences,
854 allocno[a2].hard_reg_copy_preferences);
855 IOR_HARD_REG_SET (allocno[a2].hard_reg_copy_preferences,
856 allocno[a1].hard_reg_copy_preferences);
859 IOR_HARD_REG_SET (allocno[a1].hard_reg_preferences,
860 allocno[a2].hard_reg_preferences);
861 IOR_HARD_REG_SET (allocno[a2].hard_reg_preferences,
862 allocno[a1].hard_reg_preferences);
863 IOR_HARD_REG_SET (allocno[a1].hard_reg_full_preferences,
864 allocno[a2].hard_reg_full_preferences);
865 IOR_HARD_REG_SET (allocno[a2].hard_reg_full_preferences,
866 allocno[a1].hard_reg_full_preferences);
870 /* Prune the preferences for global registers to exclude registers that cannot
873 Compute `regs_someone_prefers', which is a bitmask of the hard registers
874 that are preferred by conflicting registers of lower priority. If possible,
875 we will avoid using these registers. */
882 int *allocno_to_order = (int *) xmalloc (max_allocno * sizeof (int));
884 /* Scan least most important to most important.
885 For each allocno, remove from preferences registers that cannot be used,
886 either because of conflicts or register type. Then compute all registers
887 preferred by each lower-priority register that conflicts. */
889 for (i = max_allocno - 1; i >= 0; i--)
893 num = allocno_order[i];
894 allocno_to_order[num] = i;
895 COPY_HARD_REG_SET (temp, allocno[num].hard_reg_conflicts);
897 if (allocno[num].calls_crossed == 0)
898 IOR_HARD_REG_SET (temp, fixed_reg_set);
900 IOR_HARD_REG_SET (temp, call_used_reg_set);
902 IOR_COMPL_HARD_REG_SET
904 reg_class_contents[(int) reg_preferred_class (allocno[num].reg)]);
906 AND_COMPL_HARD_REG_SET (allocno[num].hard_reg_preferences, temp);
907 AND_COMPL_HARD_REG_SET (allocno[num].hard_reg_copy_preferences, temp);
908 AND_COMPL_HARD_REG_SET (allocno[num].hard_reg_full_preferences, temp);
911 for (i = max_allocno - 1; i >= 0; i--)
913 /* Merge in the preferences of lower-priority registers (they have
914 already been pruned). If we also prefer some of those registers,
915 don't exclude them unless we are of a smaller size (in which case
916 we want to give the lower-priority allocno the first chance for
918 HARD_REG_SET temp, temp2;
921 num = allocno_order[i];
923 CLEAR_HARD_REG_SET (temp);
924 CLEAR_HARD_REG_SET (temp2);
926 EXECUTE_IF_SET_IN_ALLOCNO_SET (conflicts + num * allocno_row_words,
929 if (allocno_to_order[allocno2] > i)
931 if (allocno[allocno2].size <= allocno[num].size)
932 IOR_HARD_REG_SET (temp,
933 allocno[allocno2].hard_reg_full_preferences);
935 IOR_HARD_REG_SET (temp2,
936 allocno[allocno2].hard_reg_full_preferences);
940 AND_COMPL_HARD_REG_SET (temp, allocno[num].hard_reg_full_preferences);
941 IOR_HARD_REG_SET (temp, temp2);
942 COPY_HARD_REG_SET (allocno[num].regs_someone_prefers, temp);
944 free (allocno_to_order);
947 /* Assign a hard register to allocno NUM; look for one that is the beginning
948 of a long enough stretch of hard regs none of which conflicts with ALLOCNO.
949 The registers marked in PREFREGS are tried first.
951 LOSERS, if non-zero, is a HARD_REG_SET indicating registers that cannot
952 be used for this allocation.
954 If ALT_REGS_P is zero, consider only the preferred class of ALLOCNO's reg.
955 Otherwise ignore that preferred class and use the alternate class.
957 If ACCEPT_CALL_CLOBBERED is nonzero, accept a call-clobbered hard reg that
958 will have to be saved and restored at calls.
960 RETRYING is nonzero if this is called from retry_global_alloc.
962 If we find one, record it in reg_renumber.
963 If not, do nothing. */
966 find_reg (num, losers, alt_regs_p, accept_call_clobbered, retrying)
970 int accept_call_clobbered;
973 register int i, best_reg, pass;
975 register /* Declare it register if it's a scalar. */
977 HARD_REG_SET used, used1, used2;
979 enum reg_class class = (alt_regs_p
980 ? reg_alternate_class (allocno[num].reg)
981 : reg_preferred_class (allocno[num].reg));
982 enum machine_mode mode = PSEUDO_REGNO_MODE (allocno[num].reg);
984 if (accept_call_clobbered)
985 COPY_HARD_REG_SET (used1, call_fixed_reg_set);
986 else if (allocno[num].calls_crossed == 0)
987 COPY_HARD_REG_SET (used1, fixed_reg_set);
989 COPY_HARD_REG_SET (used1, call_used_reg_set);
991 /* Some registers should not be allocated in global-alloc. */
992 IOR_HARD_REG_SET (used1, no_global_alloc_regs);
994 IOR_HARD_REG_SET (used1, losers);
996 IOR_COMPL_HARD_REG_SET (used1, reg_class_contents[(int) class]);
997 COPY_HARD_REG_SET (used2, used1);
999 IOR_HARD_REG_SET (used1, allocno[num].hard_reg_conflicts);
1001 #ifdef CLASS_CANNOT_CHANGE_SIZE
1002 if (REG_CHANGES_SIZE (allocno[num].reg))
1003 IOR_HARD_REG_SET (used1,
1004 reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE]);
1007 /* Try each hard reg to see if it fits. Do this in two passes.
1008 In the first pass, skip registers that are preferred by some other pseudo
1009 to give it a better chance of getting one of those registers. Only if
1010 we can't get a register when excluding those do we take one of them.
1011 However, we never allocate a register for the first time in pass 0. */
1013 COPY_HARD_REG_SET (used, used1);
1014 IOR_COMPL_HARD_REG_SET (used, regs_used_so_far);
1015 IOR_HARD_REG_SET (used, allocno[num].regs_someone_prefers);
1018 for (i = FIRST_PSEUDO_REGISTER, pass = 0;
1019 pass <= 1 && i >= FIRST_PSEUDO_REGISTER;
1023 COPY_HARD_REG_SET (used, used1);
1024 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1026 #ifdef REG_ALLOC_ORDER
1027 int regno = reg_alloc_order[i];
1031 if (! TEST_HARD_REG_BIT (used, regno)
1032 && HARD_REGNO_MODE_OK (regno, mode)
1033 && (allocno[num].calls_crossed == 0
1034 || accept_call_clobbered
1035 || ! HARD_REGNO_CALL_PART_CLOBBERED (regno, mode)))
1038 register int lim = regno + HARD_REGNO_NREGS (regno, mode);
1041 && ! TEST_HARD_REG_BIT (used, j));
1048 #ifndef REG_ALLOC_ORDER
1049 i = j; /* Skip starting points we know will lose */
1055 /* See if there is a preferred register with the same class as the register
1056 we allocated above. Making this restriction prevents register
1057 preferencing from creating worse register allocation.
1059 Remove from the preferred registers and conflicting registers. Note that
1060 additional conflicts may have been added after `prune_preferences' was
1063 First do this for those register with copy preferences, then all
1064 preferred registers. */
1066 AND_COMPL_HARD_REG_SET (allocno[num].hard_reg_copy_preferences, used);
1067 GO_IF_HARD_REG_SUBSET (allocno[num].hard_reg_copy_preferences,
1068 reg_class_contents[(int) NO_REGS], no_copy_prefs);
1072 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1073 if (TEST_HARD_REG_BIT (allocno[num].hard_reg_copy_preferences, i)
1074 && HARD_REGNO_MODE_OK (i, mode)
1075 && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg)
1076 || reg_class_subset_p (REGNO_REG_CLASS (i),
1077 REGNO_REG_CLASS (best_reg))
1078 || reg_class_subset_p (REGNO_REG_CLASS (best_reg),
1079 REGNO_REG_CLASS (i))))
1082 register int lim = i + HARD_REGNO_NREGS (i, mode);
1085 && ! TEST_HARD_REG_BIT (used, j)
1086 && (REGNO_REG_CLASS (j)
1087 == REGNO_REG_CLASS (best_reg + (j - i))
1088 || reg_class_subset_p (REGNO_REG_CLASS (j),
1089 REGNO_REG_CLASS (best_reg + (j - i)))
1090 || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)),
1091 REGNO_REG_CLASS (j))));
1102 AND_COMPL_HARD_REG_SET (allocno[num].hard_reg_preferences, used);
1103 GO_IF_HARD_REG_SUBSET (allocno[num].hard_reg_preferences,
1104 reg_class_contents[(int) NO_REGS], no_prefs);
1108 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1109 if (TEST_HARD_REG_BIT (allocno[num].hard_reg_preferences, i)
1110 && HARD_REGNO_MODE_OK (i, mode)
1111 && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg)
1112 || reg_class_subset_p (REGNO_REG_CLASS (i),
1113 REGNO_REG_CLASS (best_reg))
1114 || reg_class_subset_p (REGNO_REG_CLASS (best_reg),
1115 REGNO_REG_CLASS (i))))
1118 register int lim = i + HARD_REGNO_NREGS (i, mode);
1121 && ! TEST_HARD_REG_BIT (used, j)
1122 && (REGNO_REG_CLASS (j)
1123 == REGNO_REG_CLASS (best_reg + (j - i))
1124 || reg_class_subset_p (REGNO_REG_CLASS (j),
1125 REGNO_REG_CLASS (best_reg + (j - i)))
1126 || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)),
1127 REGNO_REG_CLASS (j))));
1138 /* If we haven't succeeded yet, try with caller-saves.
1139 We need not check to see if the current function has nonlocal
1140 labels because we don't put any pseudos that are live over calls in
1141 registers in that case. */
1143 if (flag_caller_saves && best_reg < 0)
1145 /* Did not find a register. If it would be profitable to
1146 allocate a call-clobbered register and save and restore it
1147 around calls, do that. */
1148 if (! accept_call_clobbered
1149 && allocno[num].calls_crossed != 0
1150 && CALLER_SAVE_PROFITABLE (allocno[num].n_refs,
1151 allocno[num].calls_crossed))
1153 HARD_REG_SET new_losers;
1155 CLEAR_HARD_REG_SET (new_losers);
1157 COPY_HARD_REG_SET (new_losers, losers);
1159 IOR_HARD_REG_SET(new_losers, losing_caller_save_reg_set);
1160 find_reg (num, new_losers, alt_regs_p, 1, retrying);
1161 if (reg_renumber[allocno[num].reg] >= 0)
1163 caller_save_needed = 1;
1169 /* If we haven't succeeded yet,
1170 see if some hard reg that conflicts with us
1171 was utilized poorly by local-alloc.
1172 If so, kick out the regs that were put there by local-alloc
1173 so we can use it instead. */
1174 if (best_reg < 0 && !retrying
1175 /* Let's not bother with multi-reg allocnos. */
1176 && allocno[num].size == 1)
1178 /* Count from the end, to find the least-used ones first. */
1179 for (i = FIRST_PSEUDO_REGISTER - 1; i >= 0; i--)
1181 #ifdef REG_ALLOC_ORDER
1182 int regno = reg_alloc_order[i];
1187 if (local_reg_n_refs[regno] != 0
1188 /* Don't use a reg no good for this pseudo. */
1189 && ! TEST_HARD_REG_BIT (used2, regno)
1190 && HARD_REGNO_MODE_OK (regno, mode)
1191 #ifdef CLASS_CANNOT_CHANGE_SIZE
1192 && ! (REG_CHANGES_SIZE (allocno[num].reg)
1193 && (TEST_HARD_REG_BIT
1194 (reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE],
1199 /* We explicitly evaluate the divide results into temporary
1200 variables so as to avoid excess precision problems that occur
1201 on a i386-unknown-sysv4.2 (unixware) host. */
1203 double tmp1 = ((double) local_reg_n_refs[regno]
1204 / local_reg_live_length[regno]);
1205 double tmp2 = ((double) allocno[num].n_refs
1206 / allocno[num].live_length);
1210 /* Hard reg REGNO was used less in total by local regs
1211 than it would be used by this one allocno! */
1213 for (k = 0; k < max_regno; k++)
1214 if (reg_renumber[k] >= 0)
1216 int r = reg_renumber[k];
1218 = r + HARD_REGNO_NREGS (r, PSEUDO_REGNO_MODE (k));
1220 if (regno >= r && regno < endregno)
1221 reg_renumber[k] = -1;
1231 /* Did we find a register? */
1235 register int lim, j;
1236 HARD_REG_SET this_reg;
1238 /* Yes. Record it as the hard register of this pseudo-reg. */
1239 reg_renumber[allocno[num].reg] = best_reg;
1240 /* Also of any pseudo-regs that share with it. */
1241 if (reg_may_share[allocno[num].reg])
1242 for (j = FIRST_PSEUDO_REGISTER; j < max_regno; j++)
1243 if (reg_allocno[j] == num)
1244 reg_renumber[j] = best_reg;
1246 /* Make a set of the hard regs being allocated. */
1247 CLEAR_HARD_REG_SET (this_reg);
1248 lim = best_reg + HARD_REGNO_NREGS (best_reg, mode);
1249 for (j = best_reg; j < lim; j++)
1251 SET_HARD_REG_BIT (this_reg, j);
1252 SET_HARD_REG_BIT (regs_used_so_far, j);
1253 /* This is no longer a reg used just by local regs. */
1254 local_reg_n_refs[j] = 0;
1256 /* For each other pseudo-reg conflicting with this one,
1257 mark it as conflicting with the hard regs this one occupies. */
1259 EXECUTE_IF_SET_IN_ALLOCNO_SET (conflicts + lim * allocno_row_words, j,
1261 IOR_HARD_REG_SET (allocno[j].hard_reg_conflicts, this_reg);
1266 /* Called from `reload' to look for a hard reg to put pseudo reg REGNO in.
1267 Perhaps it had previously seemed not worth a hard reg,
1268 or perhaps its old hard reg has been commandeered for reloads.
1269 FORBIDDEN_REGS indicates certain hard regs that may not be used, even if
1270 they do not appear to be allocated.
1271 If FORBIDDEN_REGS is zero, no regs are forbidden. */
1274 retry_global_alloc (regno, forbidden_regs)
1276 HARD_REG_SET forbidden_regs;
1278 int allocno = reg_allocno[regno];
1281 /* If we have more than one register class,
1282 first try allocating in the class that is cheapest
1283 for this pseudo-reg. If that fails, try any reg. */
1284 if (N_REG_CLASSES > 1)
1285 find_reg (allocno, forbidden_regs, 0, 0, 1);
1286 if (reg_renumber[regno] < 0
1287 && reg_alternate_class (regno) != NO_REGS)
1288 find_reg (allocno, forbidden_regs, 1, 0, 1);
1290 /* If we found a register, modify the RTL for the register to
1291 show the hard register, and mark that register live. */
1292 if (reg_renumber[regno] >= 0)
1294 REGNO (regno_reg_rtx[regno]) = reg_renumber[regno];
1295 mark_home_live (regno);
1300 /* Record a conflict between register REGNO
1301 and everything currently live.
1302 REGNO must not be a pseudo reg that was allocated
1303 by local_alloc; such numbers must be translated through
1304 reg_renumber before calling here. */
1307 record_one_conflict (regno)
1312 if (regno < FIRST_PSEUDO_REGISTER)
1313 /* When a hard register becomes live,
1314 record conflicts with live pseudo regs. */
1315 EXECUTE_IF_SET_IN_ALLOCNO_SET (allocnos_live, j,
1317 SET_HARD_REG_BIT (allocno[j].hard_reg_conflicts, regno);
1320 /* When a pseudo-register becomes live,
1321 record conflicts first with hard regs,
1322 then with other pseudo regs. */
1324 register int ialloc = reg_allocno[regno];
1325 register int ialloc_prod = ialloc * allocno_row_words;
1326 IOR_HARD_REG_SET (allocno[ialloc].hard_reg_conflicts, hard_regs_live);
1327 for (j = allocno_row_words - 1; j >= 0; j--)
1331 for (k = 0; k < n_no_conflict_pairs; k++)
1332 if (! ((j == no_conflict_pairs[k].allocno1
1333 && ialloc == no_conflict_pairs[k].allocno2)
1335 (j == no_conflict_pairs[k].allocno2
1336 && ialloc == no_conflict_pairs[k].allocno1)))
1338 conflicts[ialloc_prod + j] |= allocnos_live[j];
1343 /* Record all allocnos currently live as conflicting
1344 with all hard regs currently live.
1346 ALLOCNO_VEC is a vector of LEN allocnos, all allocnos that
1347 are currently live. Their bits are also flagged in allocnos_live. */
1350 record_conflicts (allocno_vec, len)
1351 register int *allocno_vec;
1356 register int ialloc_prod;
1360 num = allocno_vec[len];
1361 ialloc_prod = num * allocno_row_words;
1362 IOR_HARD_REG_SET (allocno[num].hard_reg_conflicts, hard_regs_live);
1366 /* If CONFLICTP (i, j) is true, make sure CONFLICTP (j, i) is also true. */
1371 int rw = allocno_row_words;
1372 int rwb = rw * INT_BITS;
1373 INT_TYPE *p = conflicts;
1374 INT_TYPE *q0 = conflicts, *q1, *q2;
1375 unsigned INT_TYPE mask;
1377 for (i = max_allocno - 1, mask = 1; i >= 0; i--, mask <<= 1)
1384 for (j = allocno_row_words - 1, q1 = q0; j >= 0; j--, q1 += rwb)
1386 unsigned INT_TYPE word;
1388 for (word = (unsigned INT_TYPE) *p++, q2 = q1; word;
1389 word >>= 1, q2 += rw)
1398 /* Handle the case where REG is set by the insn being scanned,
1399 during the forward scan to accumulate conflicts.
1400 Store a 1 in regs_live or allocnos_live for this register, record how many
1401 consecutive hardware registers it actually needs,
1402 and record a conflict with all other registers already live.
1404 Note that even if REG does not remain alive after this insn,
1405 we must mark it here as live, to ensure a conflict between
1406 REG and any other regs set in this insn that really do live.
1407 This is because those other regs could be considered after this.
1409 REG might actually be something other than a register;
1410 if so, we do nothing.
1412 SETTER is 0 if this register was modified by an auto-increment (i.e.,
1413 a REG_INC note was found for it). */
1416 mark_reg_store (reg, setter, data)
1418 void *data ATTRIBUTE_UNUSED;
1422 /* WORD is which word of a multi-register group is being stored.
1423 For the case where the store is actually into a SUBREG of REG.
1424 Except we don't use it; I believe the entire REG needs to be
1428 if (GET_CODE (reg) == SUBREG)
1430 word = SUBREG_WORD (reg);
1431 reg = SUBREG_REG (reg);
1434 if (GET_CODE (reg) != REG)
1437 regs_set[n_regs_set++] = reg;
1439 if (setter && GET_CODE (setter) != CLOBBER)
1440 set_preference (reg, SET_SRC (setter));
1442 regno = REGNO (reg);
1444 /* Either this is one of the max_allocno pseudo regs not allocated,
1445 or it is or has a hardware reg. First handle the pseudo-regs. */
1446 if (regno >= FIRST_PSEUDO_REGISTER)
1448 if (reg_allocno[regno] >= 0)
1450 SET_ALLOCNO_LIVE (reg_allocno[regno]);
1451 record_one_conflict (regno);
1455 if (reg_renumber[regno] >= 0)
1456 regno = reg_renumber[regno] /* + word */;
1458 /* Handle hardware regs (and pseudos allocated to hard regs). */
1459 if (regno < FIRST_PSEUDO_REGISTER && ! fixed_regs[regno])
1461 register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
1462 while (regno < last)
1464 record_one_conflict (regno);
1465 SET_HARD_REG_BIT (hard_regs_live, regno);
1471 /* Like mark_reg_set except notice just CLOBBERs; ignore SETs. */
1474 mark_reg_clobber (reg, setter, data)
1476 void *data ATTRIBUTE_UNUSED;
1478 if (GET_CODE (setter) == CLOBBER)
1479 mark_reg_store (reg, setter, data);
1482 /* Record that REG has conflicts with all the regs currently live.
1483 Do not mark REG itself as live. */
1486 mark_reg_conflicts (reg)
1491 if (GET_CODE (reg) == SUBREG)
1492 reg = SUBREG_REG (reg);
1494 if (GET_CODE (reg) != REG)
1497 regno = REGNO (reg);
1499 /* Either this is one of the max_allocno pseudo regs not allocated,
1500 or it is or has a hardware reg. First handle the pseudo-regs. */
1501 if (regno >= FIRST_PSEUDO_REGISTER)
1503 if (reg_allocno[regno] >= 0)
1504 record_one_conflict (regno);
1507 if (reg_renumber[regno] >= 0)
1508 regno = reg_renumber[regno];
1510 /* Handle hardware regs (and pseudos allocated to hard regs). */
1511 if (regno < FIRST_PSEUDO_REGISTER && ! fixed_regs[regno])
1513 register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
1514 while (regno < last)
1516 record_one_conflict (regno);
1522 /* Mark REG as being dead (following the insn being scanned now).
1523 Store a 0 in regs_live or allocnos_live for this register. */
1526 mark_reg_death (reg)
1529 register int regno = REGNO (reg);
1531 /* Either this is one of the max_allocno pseudo regs not allocated,
1532 or it is a hardware reg. First handle the pseudo-regs. */
1533 if (regno >= FIRST_PSEUDO_REGISTER)
1535 if (reg_allocno[regno] >= 0)
1536 CLEAR_ALLOCNO_LIVE (reg_allocno[regno]);
1539 /* For pseudo reg, see if it has been assigned a hardware reg. */
1540 if (reg_renumber[regno] >= 0)
1541 regno = reg_renumber[regno];
1543 /* Handle hardware regs (and pseudos allocated to hard regs). */
1544 if (regno < FIRST_PSEUDO_REGISTER && ! fixed_regs[regno])
1546 /* Pseudo regs already assigned hardware regs are treated
1547 almost the same as explicit hardware regs. */
1548 register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
1549 while (regno < last)
1551 CLEAR_HARD_REG_BIT (hard_regs_live, regno);
1557 /* Mark hard reg REGNO as currently live, assuming machine mode MODE
1558 for the value stored in it. MODE determines how many consecutive
1559 registers are actually in use. Do not record conflicts;
1560 it is assumed that the caller will do that. */
1563 mark_reg_live_nc (regno, mode)
1565 enum machine_mode mode;
1567 register int last = regno + HARD_REGNO_NREGS (regno, mode);
1568 while (regno < last)
1570 SET_HARD_REG_BIT (hard_regs_live, regno);
1575 /* Try to set a preference for an allocno to a hard register.
1576 We are passed DEST and SRC which are the operands of a SET. It is known
1577 that SRC is a register. If SRC or the first operand of SRC is a register,
1578 try to set a preference. If one of the two is a hard register and the other
1579 is a pseudo-register, mark the preference.
1581 Note that we are not as aggressive as local-alloc in trying to tie a
1582 pseudo-register to a hard register. */
1585 set_preference (dest, src)
1588 int src_regno, dest_regno;
1589 /* Amount to add to the hard regno for SRC, or subtract from that for DEST,
1590 to compensate for subregs in SRC or DEST. */
1595 if (GET_RTX_FORMAT (GET_CODE (src))[0] == 'e')
1596 src = XEXP (src, 0), copy = 0;
1598 /* Get the reg number for both SRC and DEST.
1599 If neither is a reg, give up. */
1601 if (GET_CODE (src) == REG)
1602 src_regno = REGNO (src);
1603 else if (GET_CODE (src) == SUBREG && GET_CODE (SUBREG_REG (src)) == REG)
1605 src_regno = REGNO (SUBREG_REG (src));
1606 offset += SUBREG_WORD (src);
1611 if (GET_CODE (dest) == REG)
1612 dest_regno = REGNO (dest);
1613 else if (GET_CODE (dest) == SUBREG && GET_CODE (SUBREG_REG (dest)) == REG)
1615 dest_regno = REGNO (SUBREG_REG (dest));
1616 offset -= SUBREG_WORD (dest);
1621 /* Convert either or both to hard reg numbers. */
1623 if (reg_renumber[src_regno] >= 0)
1624 src_regno = reg_renumber[src_regno];
1626 if (reg_renumber[dest_regno] >= 0)
1627 dest_regno = reg_renumber[dest_regno];
1629 /* Now if one is a hard reg and the other is a global pseudo
1630 then give the other a preference. */
1632 if (dest_regno < FIRST_PSEUDO_REGISTER && src_regno >= FIRST_PSEUDO_REGISTER
1633 && reg_allocno[src_regno] >= 0)
1635 dest_regno -= offset;
1636 if (dest_regno >= 0 && dest_regno < FIRST_PSEUDO_REGISTER)
1639 SET_REGBIT (hard_reg_copy_preferences,
1640 reg_allocno[src_regno], dest_regno);
1642 SET_REGBIT (hard_reg_preferences,
1643 reg_allocno[src_regno], dest_regno);
1644 for (i = dest_regno;
1645 i < dest_regno + HARD_REGNO_NREGS (dest_regno, GET_MODE (dest));
1647 SET_REGBIT (hard_reg_full_preferences, reg_allocno[src_regno], i);
1651 if (src_regno < FIRST_PSEUDO_REGISTER && dest_regno >= FIRST_PSEUDO_REGISTER
1652 && reg_allocno[dest_regno] >= 0)
1654 src_regno += offset;
1655 if (src_regno >= 0 && src_regno < FIRST_PSEUDO_REGISTER)
1658 SET_REGBIT (hard_reg_copy_preferences,
1659 reg_allocno[dest_regno], src_regno);
1661 SET_REGBIT (hard_reg_preferences,
1662 reg_allocno[dest_regno], src_regno);
1664 i < src_regno + HARD_REGNO_NREGS (src_regno, GET_MODE (src));
1666 SET_REGBIT (hard_reg_full_preferences, reg_allocno[dest_regno], i);
1671 /* Indicate that hard register number FROM was eliminated and replaced with
1672 an offset from hard register number TO. The status of hard registers live
1673 at the start of a basic block is updated by replacing a use of FROM with
1677 mark_elimination (from, to)
1682 for (i = 0; i < n_basic_blocks; i++)
1684 register regset r = BASIC_BLOCK (i)->global_live_at_start;
1685 if (REGNO_REG_SET_P (r, from))
1687 CLEAR_REGNO_REG_SET (r, from);
1688 SET_REGNO_REG_SET (r, to);
1693 /* Used for communication between the following functions. Holds the
1694 current life information. */
1695 static regset live_relevant_regs;
1697 /* Record in live_relevant_regs that register REG became live. This
1698 is called via note_stores. */
1700 reg_becomes_live (reg, setter, data)
1702 rtx setter ATTRIBUTE_UNUSED;
1703 void *data ATTRIBUTE_UNUSED;
1707 if (GET_CODE (reg) == SUBREG)
1708 reg = SUBREG_REG (reg);
1710 if (GET_CODE (reg) != REG)
1713 regno = REGNO (reg);
1714 if (regno < FIRST_PSEUDO_REGISTER)
1716 int nregs = HARD_REGNO_NREGS (regno, GET_MODE (reg));
1718 SET_REGNO_REG_SET (live_relevant_regs, regno++);
1720 else if (reg_renumber[regno] >= 0)
1721 SET_REGNO_REG_SET (live_relevant_regs, regno);
1724 /* Record in live_relevant_regs that register REGNO died. */
1726 reg_dies (regno, mode)
1728 enum machine_mode mode;
1730 if (regno < FIRST_PSEUDO_REGISTER)
1732 int nregs = HARD_REGNO_NREGS (regno, mode);
1734 CLEAR_REGNO_REG_SET (live_relevant_regs, regno++);
1737 CLEAR_REGNO_REG_SET (live_relevant_regs, regno);
1740 /* Walk the insns of the current function and build reload_insn_chain,
1741 and record register life information. */
1743 build_insn_chain (first)
1746 struct insn_chain **p = &reload_insn_chain;
1747 struct insn_chain *prev = 0;
1750 live_relevant_regs = ALLOCA_REG_SET ();
1752 for (; first; first = NEXT_INSN (first))
1754 struct insn_chain *c;
1756 if (first == BLOCK_HEAD (b))
1760 CLEAR_REG_SET (live_relevant_regs);
1762 EXECUTE_IF_SET_IN_BITMAP
1763 (BASIC_BLOCK (b)->global_live_at_start, 0, i,
1765 if (i < FIRST_PSEUDO_REGISTER
1766 ? ! TEST_HARD_REG_BIT (eliminable_regset, i)
1767 : reg_renumber[i] >= 0)
1768 SET_REGNO_REG_SET (live_relevant_regs, i);
1772 if (GET_CODE (first) != NOTE && GET_CODE (first) != BARRIER)
1774 c = new_insn_chain ();
1782 COPY_REG_SET (c->live_before, live_relevant_regs);
1784 if (GET_RTX_CLASS (GET_CODE (first)) == 'i')
1788 /* Mark the death of everything that dies in this instruction. */
1790 for (link = REG_NOTES (first); link; link = XEXP (link, 1))
1791 if (REG_NOTE_KIND (link) == REG_DEAD
1792 && GET_CODE (XEXP (link, 0)) == REG)
1793 reg_dies (REGNO (XEXP (link, 0)), GET_MODE (XEXP (link, 0)));
1795 /* Mark everything born in this instruction as live. */
1797 note_stores (PATTERN (first), reg_becomes_live, NULL);
1800 /* Remember which registers are live at the end of the insn, before
1801 killing those with REG_UNUSED notes. */
1802 COPY_REG_SET (c->live_after, live_relevant_regs);
1804 if (GET_RTX_CLASS (GET_CODE (first)) == 'i')
1808 /* Mark anything that is set in this insn and then unused as dying. */
1810 for (link = REG_NOTES (first); link; link = XEXP (link, 1))
1811 if (REG_NOTE_KIND (link) == REG_UNUSED
1812 && GET_CODE (XEXP (link, 0)) == REG)
1813 reg_dies (REGNO (XEXP (link, 0)), GET_MODE (XEXP (link, 0)));
1817 if (first == BLOCK_END (b))
1820 /* Stop after we pass the end of the last basic block. Verify that
1821 no real insns are after the end of the last basic block.
1823 We may want to reorganize the loop somewhat since this test should
1824 always be the right exit test. */
1825 if (b == n_basic_blocks)
1827 for (first = NEXT_INSN (first) ; first; first = NEXT_INSN (first))
1828 if (GET_RTX_CLASS (GET_CODE (first)) == 'i'
1829 && GET_CODE (PATTERN (first)) != USE)
1834 FREE_REG_SET (live_relevant_regs);
1838 /* Print debugging trace information if -dg switch is given,
1839 showing the information on which the allocation decisions are based. */
1842 dump_conflicts (file)
1846 register int has_preferences;
1849 for (i = 0; i < max_allocno; i++)
1851 if (reg_renumber[allocno[allocno_order[i]].reg] >= 0)
1855 fprintf (file, ";; %d regs to allocate:", nregs);
1856 for (i = 0; i < max_allocno; i++)
1859 if (reg_renumber[allocno[allocno_order[i]].reg] >= 0)
1861 fprintf (file, " %d", allocno[allocno_order[i]].reg);
1862 for (j = 0; j < max_regno; j++)
1863 if (reg_allocno[j] == allocno_order[i]
1864 && j != allocno[allocno_order[i]].reg)
1865 fprintf (file, "+%d", j);
1866 if (allocno[allocno_order[i]].size != 1)
1867 fprintf (file, " (%d)", allocno[allocno_order[i]].size);
1869 fprintf (file, "\n");
1871 for (i = 0; i < max_allocno; i++)
1874 fprintf (file, ";; %d conflicts:", allocno[i].reg);
1875 for (j = 0; j < max_allocno; j++)
1876 if (CONFLICTP (j, i))
1877 fprintf (file, " %d", allocno[j].reg);
1878 for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
1879 if (TEST_HARD_REG_BIT (allocno[i].hard_reg_conflicts, j))
1880 fprintf (file, " %d", j);
1881 fprintf (file, "\n");
1883 has_preferences = 0;
1884 for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
1885 if (TEST_HARD_REG_BIT (allocno[i].hard_reg_preferences, j))
1886 has_preferences = 1;
1888 if (! has_preferences)
1890 fprintf (file, ";; %d preferences:", allocno[i].reg);
1891 for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
1892 if (TEST_HARD_REG_BIT (allocno[i].hard_reg_preferences, j))
1893 fprintf (file, " %d", j);
1894 fprintf (file, "\n");
1896 fprintf (file, "\n");
1900 dump_global_regs (file)
1905 fprintf (file, ";; Register dispositions:\n");
1906 for (i = FIRST_PSEUDO_REGISTER, j = 0; i < max_regno; i++)
1907 if (reg_renumber[i] >= 0)
1909 fprintf (file, "%d in %d ", i, reg_renumber[i]);
1911 fprintf (file, "\n");
1914 fprintf (file, "\n\n;; Hard regs used: ");
1915 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1916 if (regs_ever_live[i])
1917 fprintf (file, " %d", i);
1918 fprintf (file, "\n\n");