1 /* Save and restore call-clobbered registers which are live across a call.
2 Copyright (C) 1989, 1992, 1994, 1995, 1997, 1998,
3 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
25 #include "insn-config.h"
28 #include "hard-reg-set.h"
30 #include "basic-block.h"
38 #define MAX_MOVE_MAX MOVE_MAX
41 #ifndef MIN_UNITS_PER_WORD
42 #define MIN_UNITS_PER_WORD UNITS_PER_WORD
45 #define MOVE_MAX_WORDS (MOVE_MAX / UNITS_PER_WORD)
47 /* Modes for each hard register that we can save. The smallest mode is wide
48 enough to save the entire contents of the register. When saving the
49 register because it is live we first try to save in multi-register modes.
50 If that is not possible the save is done one register at a time. */
52 static enum machine_mode
53 regno_save_mode[FIRST_PSEUDO_REGISTER][MAX_MOVE_MAX / MIN_UNITS_PER_WORD + 1];
55 /* For each hard register, a place on the stack where it can be saved,
59 regno_save_mem[FIRST_PSEUDO_REGISTER][MAX_MOVE_MAX / MIN_UNITS_PER_WORD + 1];
61 /* We will only make a register eligible for caller-save if it can be
62 saved in its widest mode with a simple SET insn as long as the memory
63 address is valid. We record the INSN_CODE is those insns here since
64 when we emit them, the addresses might not be valid, so they might not
68 reg_save_code[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
70 reg_restore_code[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
72 /* Set of hard regs currently residing in save area (during insn scan). */
74 static HARD_REG_SET hard_regs_saved;
76 /* Number of registers currently in hard_regs_saved. */
78 static int n_regs_saved;
80 /* Computed by mark_referenced_regs, all regs referenced in a given
82 static HARD_REG_SET referenced_regs;
84 /* Computed in mark_set_regs, holds all registers set by the current
86 static HARD_REG_SET this_insn_sets;
89 static void mark_set_regs PARAMS ((rtx, rtx, void *));
90 static void mark_referenced_regs PARAMS ((rtx));
91 static int insert_save PARAMS ((struct insn_chain *, int, int,
93 enum machine_mode *));
94 static int insert_restore PARAMS ((struct insn_chain *, int, int,
95 int, enum machine_mode *));
96 static struct insn_chain *insert_one_insn PARAMS ((struct insn_chain *, int,
98 static void add_stored_regs PARAMS ((rtx, rtx, void *));
100 /* Initialize for caller-save.
102 Look at all the hard registers that are used by a call and for which
103 regclass.c has not already excluded from being used across a call.
105 Ensure that we can find a mode to save the register and that there is a
106 simple insn to save and restore the register. This latter check avoids
107 problems that would occur if we tried to save the MQ register of some
108 machines directly into memory. */
117 enum machine_mode mode;
118 rtx savepat, restpat;
119 rtx test_reg, test_mem;
120 rtx saveinsn, restinsn;
122 /* First find all the registers that we need to deal with and all
123 the modes that they can have. If we can't find a mode to use,
124 we can't have the register live over calls. */
126 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
128 if (call_used_regs[i] && ! call_fixed_regs[i])
130 for (j = 1; j <= MOVE_MAX_WORDS; j++)
132 regno_save_mode[i][j] = HARD_REGNO_CALLER_SAVE_MODE (i, j,
134 if (regno_save_mode[i][j] == VOIDmode && j == 1)
136 call_fixed_regs[i] = 1;
137 SET_HARD_REG_BIT (call_fixed_reg_set, i);
142 regno_save_mode[i][1] = VOIDmode;
145 /* The following code tries to approximate the conditions under which
146 we can easily save and restore a register without scratch registers or
147 other complexities. It will usually work, except under conditions where
148 the validity of an insn operand is dependent on the address offset.
149 No such cases are currently known.
151 We first find a typical offset from some BASE_REG_CLASS register.
152 This address is chosen by finding the first register in the class
153 and by finding the smallest power of two that is a valid offset from
154 that register in every mode we will use to save registers. */
156 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
157 if (TEST_HARD_REG_BIT
159 [(int) MODE_BASE_REG_CLASS (regno_save_mode [i][1])], i))
162 if (i == FIRST_PSEUDO_REGISTER)
165 addr_reg = gen_rtx_REG (Pmode, i);
167 for (offset = 1 << (HOST_BITS_PER_INT / 2); offset; offset >>= 1)
169 address = gen_rtx_PLUS (Pmode, addr_reg, GEN_INT (offset));
171 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
172 if (regno_save_mode[i][1] != VOIDmode
173 && ! strict_memory_address_p (regno_save_mode[i][1], address))
176 if (i == FIRST_PSEUDO_REGISTER)
180 /* If we didn't find a valid address, we must use register indirect. */
184 /* Next we try to form an insn to save and restore the register. We
185 see if such an insn is recognized and meets its constraints.
187 To avoid lots of unnecessary RTL allocation, we construct all the RTL
188 once, then modify the memory and register operands in-place. */
190 test_reg = gen_rtx_REG (VOIDmode, 0);
191 test_mem = gen_rtx_MEM (VOIDmode, address);
192 savepat = gen_rtx_SET (VOIDmode, test_mem, test_reg);
193 restpat = gen_rtx_SET (VOIDmode, test_reg, test_mem);
197 saveinsn = emit_insn (savepat);
198 restinsn = emit_insn (restpat);
200 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
201 for (mode = 0 ; mode < MAX_MACHINE_MODE; mode++)
202 if (HARD_REGNO_MODE_OK (i, mode))
206 /* Update the register number and modes of the register
207 and memory operand. */
208 REGNO (test_reg) = i;
209 PUT_MODE (test_reg, mode);
210 PUT_MODE (test_mem, mode);
212 /* Force re-recognition of the modified insns. */
213 INSN_CODE (saveinsn) = -1;
214 INSN_CODE (restinsn) = -1;
216 reg_save_code[i][mode] = recog_memoized (saveinsn);
217 reg_restore_code[i][mode] = recog_memoized (restinsn);
219 /* Now extract both insns and see if we can meet their
221 ok = (reg_save_code[i][mode] != -1
222 && reg_restore_code[i][mode] != -1);
225 extract_insn (saveinsn);
226 ok = constrain_operands (1);
227 extract_insn (restinsn);
228 ok &= constrain_operands (1);
233 reg_save_code[i][mode] = -1;
234 reg_restore_code[i][mode] = -1;
239 reg_save_code[i][mode] = -1;
240 reg_restore_code[i][mode] = -1;
243 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
244 for (j = 1; j <= MOVE_MAX_WORDS; j++)
245 if (reg_save_code [i][regno_save_mode[i][j]] == -1)
247 regno_save_mode[i][j] = VOIDmode;
250 call_fixed_regs[i] = 1;
251 SET_HARD_REG_BIT (call_fixed_reg_set, i);
258 /* Initialize save areas by showing that we haven't allocated any yet. */
265 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
266 for (j = 1; j <= MOVE_MAX_WORDS; j++)
267 regno_save_mem[i][j] = 0;
270 /* Allocate save areas for any hard registers that might need saving.
271 We take a conservative approach here and look for call-clobbered hard
272 registers that are assigned to pseudos that cross calls. This may
273 overestimate slightly (especially if some of these registers are later
274 used as spill registers), but it should not be significant.
278 In the fallback case we should iterate backwards across all possible
279 modes for the save, choosing the largest available one instead of
280 falling back to the smallest mode immediately. (eg TF -> DF -> SF).
282 We do not try to use "move multiple" instructions that exist
283 on some machines (such as the 68k moveml). It could be a win to try
284 and use them when possible. The hard part is doing it in a way that is
285 machine independent since they might be saving non-consecutive
286 registers. (imagine caller-saving d0,d1,a0,a1 on the 68k) */
293 HARD_REG_SET hard_regs_used;
295 /* Allocate space in the save area for the largest multi-register
296 pseudos first, then work backwards to single register
299 /* Find and record all call-used hard-registers in this function. */
300 CLEAR_HARD_REG_SET (hard_regs_used);
301 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
302 if (reg_renumber[i] >= 0 && REG_N_CALLS_CROSSED (i) > 0)
304 unsigned int regno = reg_renumber[i];
305 unsigned int endregno
306 = regno + HARD_REGNO_NREGS (regno, GET_MODE (regno_reg_rtx[i]));
308 for (r = regno; r < endregno; r++)
309 if (call_used_regs[r])
310 SET_HARD_REG_BIT (hard_regs_used, r);
313 /* Now run through all the call-used hard-registers and allocate
314 space for them in the caller-save area. Try to allocate space
315 in a manner which allows multi-register saves/restores to be done. */
317 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
318 for (j = MOVE_MAX_WORDS; j > 0; j--)
322 /* If no mode exists for this size, try another. Also break out
323 if we have already saved this hard register. */
324 if (regno_save_mode[i][j] == VOIDmode || regno_save_mem[i][1] != 0)
327 /* See if any register in this group has been saved. */
328 for (k = 0; k < j; k++)
329 if (regno_save_mem[i + k][1])
337 for (k = 0; k < j; k++)
338 if (! TEST_HARD_REG_BIT (hard_regs_used, i + k))
346 /* We have found an acceptable mode to store in. */
348 = assign_stack_local (regno_save_mode[i][j],
349 GET_MODE_SIZE (regno_save_mode[i][j]), 0);
351 /* Setup single word save area just in case... */
352 for (k = 0; k < j; k++)
353 /* This should not depend on WORDS_BIG_ENDIAN.
354 The order of words in regs is the same as in memory. */
355 regno_save_mem[i + k][1]
356 = adjust_address_nv (regno_save_mem[i][j],
357 regno_save_mode[i + k][1],
361 /* Now loop again and set the alias set of any save areas we made to
362 the alias set used to represent frame objects. */
363 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
364 for (j = MOVE_MAX_WORDS; j > 0; j--)
365 if (regno_save_mem[i][j] != 0)
366 set_mem_alias_set (regno_save_mem[i][j], get_frame_alias_set ());
369 /* Find the places where hard regs are live across calls and save them. */
372 save_call_clobbered_regs ()
374 struct insn_chain *chain, *next;
375 enum machine_mode save_mode [FIRST_PSEUDO_REGISTER];
377 CLEAR_HARD_REG_SET (hard_regs_saved);
380 for (chain = reload_insn_chain; chain != 0; chain = next)
382 rtx insn = chain->insn;
383 enum rtx_code code = GET_CODE (insn);
387 if (chain->is_caller_save_insn)
390 if (GET_RTX_CLASS (code) == 'i')
392 /* If some registers have been saved, see if INSN references
393 any of them. We must restore them before the insn if so. */
399 if (code == JUMP_INSN)
400 /* Restore all registers if this is a JUMP_INSN. */
401 COPY_HARD_REG_SET (referenced_regs, hard_regs_saved);
404 CLEAR_HARD_REG_SET (referenced_regs);
405 mark_referenced_regs (PATTERN (insn));
406 AND_HARD_REG_SET (referenced_regs, hard_regs_saved);
409 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
410 if (TEST_HARD_REG_BIT (referenced_regs, regno))
411 regno += insert_restore (chain, 1, regno, MOVE_MAX_WORDS, save_mode);
414 if (code == CALL_INSN)
417 HARD_REG_SET hard_regs_to_save;
419 /* Use the register life information in CHAIN to compute which
420 regs are live during the call. */
421 REG_SET_TO_HARD_REG_SET (hard_regs_to_save,
422 &chain->live_throughout);
423 /* Save hard registers always in the widest mode available. */
424 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
425 if (TEST_HARD_REG_BIT (hard_regs_to_save, regno))
426 save_mode [regno] = regno_save_mode [regno][1];
428 save_mode [regno] = VOIDmode;
430 /* Look through all live pseudos, mark their hard registers
431 and choose proper mode for saving. */
432 EXECUTE_IF_SET_IN_REG_SET
433 (&chain->live_throughout, FIRST_PSEUDO_REGISTER, regno,
435 int r = reg_renumber[regno];
440 enum machine_mode mode;
442 nregs = HARD_REGNO_NREGS (r, PSEUDO_REGNO_MODE (regno));
443 mode = HARD_REGNO_CALLER_SAVE_MODE
444 (r, nregs, PSEUDO_REGNO_MODE (regno));
445 if (GET_MODE_BITSIZE (mode)
446 > GET_MODE_BITSIZE (save_mode[r]))
449 SET_HARD_REG_BIT (hard_regs_to_save, r + nregs);
455 /* Record all registers set in this call insn. These don't need
456 to be saved. N.B. the call insn might set a subreg of a
457 multi-hard-reg pseudo; then the pseudo is considered live
458 during the call, but the subreg that is set isn't. */
459 CLEAR_HARD_REG_SET (this_insn_sets);
460 note_stores (PATTERN (insn), mark_set_regs, NULL);
462 /* Compute which hard regs must be saved before this call. */
463 AND_COMPL_HARD_REG_SET (hard_regs_to_save, call_fixed_reg_set);
464 AND_COMPL_HARD_REG_SET (hard_regs_to_save, this_insn_sets);
465 AND_COMPL_HARD_REG_SET (hard_regs_to_save, hard_regs_saved);
466 AND_HARD_REG_SET (hard_regs_to_save, call_used_reg_set);
468 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
469 if (TEST_HARD_REG_BIT (hard_regs_to_save, regno))
470 regno += insert_save (chain, 1, regno, &hard_regs_to_save, save_mode);
472 /* Must recompute n_regs_saved. */
474 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
475 if (TEST_HARD_REG_BIT (hard_regs_saved, regno))
480 if (chain->next == 0 || chain->next->block > chain->block)
483 /* At the end of the basic block, we must restore any registers that
484 remain saved. If the last insn in the block is a JUMP_INSN, put
485 the restore before the insn, otherwise, put it after the insn. */
488 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
489 if (TEST_HARD_REG_BIT (hard_regs_saved, regno))
490 regno += insert_restore (chain, GET_CODE (insn) == JUMP_INSN,
491 regno, MOVE_MAX_WORDS, save_mode);
496 /* Here from note_stores when an insn stores a value in a register.
497 Set the proper bit or bits in this_insn_sets. All pseudos that have
498 been assigned hard regs have had their register number changed already,
499 so we can ignore pseudos. */
501 mark_set_regs (reg, setter, data)
503 rtx setter ATTRIBUTE_UNUSED;
504 void *data ATTRIBUTE_UNUSED;
506 int regno, endregno, i;
507 enum machine_mode mode = GET_MODE (reg);
509 if (GET_CODE (reg) == SUBREG)
511 rtx inner = SUBREG_REG (reg);
512 if (GET_CODE (inner) != REG || REGNO (inner) >= FIRST_PSEUDO_REGISTER)
515 regno = subreg_hard_regno (reg, 1);
517 else if (GET_CODE (reg) == REG
518 && REGNO (reg) < FIRST_PSEUDO_REGISTER)
523 endregno = regno + HARD_REGNO_NREGS (regno, mode);
525 for (i = regno; i < endregno; i++)
526 SET_HARD_REG_BIT (this_insn_sets, i);
529 /* Here from note_stores when an insn stores a value in a register.
530 Set the proper bit or bits in the passed regset. All pseudos that have
531 been assigned hard regs have had their register number changed already,
532 so we can ignore pseudos. */
534 add_stored_regs (reg, setter, data)
539 int regno, endregno, i;
540 enum machine_mode mode = GET_MODE (reg);
543 if (GET_CODE (setter) == CLOBBER)
546 if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
548 offset = subreg_regno_offset (REGNO (SUBREG_REG (reg)),
549 GET_MODE (SUBREG_REG (reg)),
552 reg = SUBREG_REG (reg);
555 if (GET_CODE (reg) != REG || REGNO (reg) >= FIRST_PSEUDO_REGISTER)
558 regno = REGNO (reg) + offset;
559 endregno = regno + HARD_REGNO_NREGS (regno, mode);
561 for (i = regno; i < endregno; i++)
562 SET_REGNO_REG_SET ((regset) data, i);
565 /* Walk X and record all referenced registers in REFERENCED_REGS. */
567 mark_referenced_regs (x)
570 enum rtx_code code = GET_CODE (x);
575 mark_referenced_regs (SET_SRC (x));
576 if (code == SET || code == CLOBBER)
580 if (code == REG || code == PC || code == CC0
581 || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG
582 /* If we're setting only part of a multi-word register,
583 we shall mark it as referenced, because the words
584 that are not being set should be restored. */
585 && ((GET_MODE_SIZE (GET_MODE (x))
586 >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
587 || (GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))
588 <= UNITS_PER_WORD))))
591 if (code == MEM || code == SUBREG)
599 int regno = REGNO (x);
600 int hardregno = (regno < FIRST_PSEUDO_REGISTER ? regno
601 : reg_renumber[regno]);
605 int nregs = HARD_REGNO_NREGS (hardregno, GET_MODE (x));
607 SET_HARD_REG_BIT (referenced_regs, hardregno + nregs);
609 /* If this is a pseudo that did not get a hard register, scan its
610 memory location, since it might involve the use of another
611 register, which might be saved. */
612 else if (reg_equiv_mem[regno] != 0)
613 mark_referenced_regs (XEXP (reg_equiv_mem[regno], 0));
614 else if (reg_equiv_address[regno] != 0)
615 mark_referenced_regs (reg_equiv_address[regno]);
619 fmt = GET_RTX_FORMAT (code);
620 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
623 mark_referenced_regs (XEXP (x, i));
624 else if (fmt[i] == 'E')
625 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
626 mark_referenced_regs (XVECEXP (x, i, j));
630 /* Insert a sequence of insns to restore. Place these insns in front of
631 CHAIN if BEFORE_P is nonzero, behind the insn otherwise. MAXRESTORE is
632 the maximum number of registers which should be restored during this call.
633 It should never be less than 1 since we only work with entire registers.
635 Note that we have verified in init_caller_save that we can do this
636 with a simple SET, so use it. Set INSN_CODE to what we save there
637 since the address might not be valid so the insn might not be recognized.
638 These insns will be reloaded and have register elimination done by
639 find_reload, so we need not worry about that here.
641 Return the extra number of registers saved. */
644 insert_restore (chain, before_p, regno, maxrestore, save_mode)
645 struct insn_chain *chain;
649 enum machine_mode *save_mode;
654 unsigned int numregs = 0;
655 struct insn_chain *new;
658 /* A common failure mode if register status is not correct in the RTL
659 is for this routine to be called with a REGNO we didn't expect to
660 save. That will cause us to write an insn with a (nil) SET_DEST
661 or SET_SRC. Instead of doing so and causing a crash later, check
662 for this common case and abort here instead. This will remove one
663 step in debugging such problems. */
665 if (regno_save_mem[regno][1] == 0)
668 /* Get the pattern to emit and update our status.
670 See if we can restore `maxrestore' registers at once. Work
671 backwards to the single register case. */
672 for (i = maxrestore; i > 0; i--)
677 if (regno_save_mem[regno][i] == 0)
680 for (j = 0; j < i; j++)
681 if (! TEST_HARD_REG_BIT (hard_regs_saved, regno + j))
686 /* Must do this one restore at a time */
694 mem = regno_save_mem [regno][numregs];
695 if (save_mode [regno] != VOIDmode
696 && save_mode [regno] != GET_MODE (mem)
697 && numregs == (unsigned int) HARD_REGNO_NREGS (regno, save_mode [regno]))
698 mem = adjust_address (mem, save_mode[regno], 0);
699 pat = gen_rtx_SET (VOIDmode,
700 gen_rtx_REG (GET_MODE (mem),
702 code = reg_restore_code[regno][GET_MODE (mem)];
703 new = insert_one_insn (chain, before_p, code, pat);
705 /* Clear status for all registers we restored. */
706 for (k = 0; k < i; k++)
708 CLEAR_HARD_REG_BIT (hard_regs_saved, regno + k);
709 SET_REGNO_REG_SET (&new->dead_or_set, regno + k);
713 /* Tell our callers how many extra registers we saved/restored */
717 /* Like insert_restore above, but save registers instead. */
720 insert_save (chain, before_p, regno, to_save, save_mode)
721 struct insn_chain *chain;
724 HARD_REG_SET *to_save;
725 enum machine_mode *save_mode;
731 unsigned int numregs = 0;
732 struct insn_chain *new;
735 /* A common failure mode if register status is not correct in the RTL
736 is for this routine to be called with a REGNO we didn't expect to
737 save. That will cause us to write an insn with a (nil) SET_DEST
738 or SET_SRC. Instead of doing so and causing a crash later, check
739 for this common case and abort here instead. This will remove one
740 step in debugging such problems. */
742 if (regno_save_mem[regno][1] == 0)
745 /* Get the pattern to emit and update our status.
747 See if we can save several registers with a single instruction.
748 Work backwards to the single register case. */
749 for (i = MOVE_MAX_WORDS; i > 0; i--)
753 if (regno_save_mem[regno][i] == 0)
756 for (j = 0; j < i; j++)
757 if (! TEST_HARD_REG_BIT (*to_save, regno + j))
762 /* Must do this one save at a time */
770 mem = regno_save_mem [regno][numregs];
771 if (save_mode [regno] != VOIDmode
772 && save_mode [regno] != GET_MODE (mem)
773 && numregs == (unsigned int) HARD_REGNO_NREGS (regno, save_mode [regno]))
774 mem = adjust_address (mem, save_mode[regno], 0);
775 pat = gen_rtx_SET (VOIDmode, mem,
776 gen_rtx_REG (GET_MODE (mem),
778 code = reg_save_code[regno][GET_MODE (mem)];
779 new = insert_one_insn (chain, before_p, code, pat);
781 /* Set hard_regs_saved and dead_or_set for all the registers we saved. */
782 for (k = 0; k < numregs; k++)
784 SET_HARD_REG_BIT (hard_regs_saved, regno + k);
785 SET_REGNO_REG_SET (&new->dead_or_set, regno + k);
789 /* Tell our callers how many extra registers we saved/restored */
793 /* Emit a new caller-save insn and set the code. */
794 static struct insn_chain *
795 insert_one_insn (chain, before_p, code, pat)
796 struct insn_chain *chain;
801 rtx insn = chain->insn;
802 struct insn_chain *new;
805 /* If INSN references CC0, put our insns in front of the insn that sets
806 CC0. This is always safe, since the only way we could be passed an
807 insn that references CC0 is for a restore, and doing a restore earlier
808 isn't a problem. We do, however, assume here that CALL_INSNs don't
809 reference CC0. Guard against non-INSN's like CODE_LABEL. */
811 if ((GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN)
813 && reg_referenced_p (cc0_rtx, PATTERN (insn)))
814 chain = chain->prev, insn = chain->insn;
817 new = new_insn_chain ();
822 new->prev = chain->prev;
824 new->prev->next = new;
826 reload_insn_chain = new;
830 new->insn = emit_insn_before (pat, insn);
831 /* ??? It would be nice if we could exclude the already / still saved
832 registers from the live sets. */
833 COPY_REG_SET (&new->live_throughout, &chain->live_throughout);
834 /* Registers that die in CHAIN->INSN still live in the new insn. */
835 for (link = REG_NOTES (chain->insn); link; link = XEXP (link, 1))
837 if (REG_NOTE_KIND (link) == REG_DEAD)
839 rtx reg = XEXP (link, 0);
842 if (GET_CODE (reg) != REG)
846 if (regno >= FIRST_PSEUDO_REGISTER)
847 regno = reg_renumber[regno];
850 for (i = HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
852 SET_REGNO_REG_SET (&new->live_throughout, regno + i);
855 CLEAR_REG_SET (&new->dead_or_set);
856 if (chain->insn == BLOCK_HEAD (chain->block))
857 BLOCK_HEAD (chain->block) = new->insn;
861 new->next = chain->next;
863 new->next->prev = new;
866 new->insn = emit_insn_after (pat, insn);
867 /* ??? It would be nice if we could exclude the already / still saved
868 registers from the live sets, and observe REG_UNUSED notes. */
869 COPY_REG_SET (&new->live_throughout, &chain->live_throughout);
870 /* Registers that are set in CHAIN->INSN live in the new insn.
871 (Unless there is a REG_UNUSED note for them, but we don't
872 look for them here.) */
873 note_stores (PATTERN (chain->insn), add_stored_regs,
874 &new->live_throughout);
875 CLEAR_REG_SET (&new->dead_or_set);
876 if (chain->insn == BLOCK_END (chain->block))
877 BLOCK_END (chain->block) = new->insn;
879 new->block = chain->block;
880 new->is_caller_save_insn = 1;
882 INSN_CODE (new->insn) = code;