1 /* Reload pseudo regs into hard regs for insns that require hard regs.
2 Copyright (C) 1987, 1988, 1989, 1992 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, 675 Mass Ave, Cambridge, MA 02139, USA. */
25 #include "insn-config.h"
26 #include "insn-flags.h"
27 #include "insn-codes.h"
31 #include "hard-reg-set.h"
34 #include "basic-block.h"
37 /* This file contains the reload pass of the compiler, which is
38 run after register allocation has been done. It checks that
39 each insn is valid (operands required to be in registers really
40 are in registers of the proper class) and fixes up invalid ones
41 by copying values temporarily into registers for the insns
44 The results of register allocation are described by the vector
45 reg_renumber; the insns still contain pseudo regs, but reg_renumber
46 can be used to find which hard reg, if any, a pseudo reg is in.
48 The technique we always use is to free up a few hard regs that are
49 called ``reload regs'', and for each place where a pseudo reg
50 must be in a hard reg, copy it temporarily into one of the reload regs.
52 All the pseudos that were formerly allocated to the hard regs that
53 are now in use as reload regs must be ``spilled''. This means
54 that they go to other hard regs, or to stack slots if no other
55 available hard regs can be found. Spilling can invalidate more
56 insns, requiring additional need for reloads, so we must keep checking
57 until the process stabilizes.
59 For machines with different classes of registers, we must keep track
60 of the register class needed for each reload, and make sure that
61 we allocate enough reload registers of each class.
63 The file reload.c contains the code that checks one insn for
64 validity and reports the reloads that it needs. This file
65 is in charge of scanning the entire rtl code, accumulating the
66 reload needs, spilling, assigning reload registers to use for
67 fixing up each insn, and generating the new insns to copy values
68 into the reload registers. */
70 /* During reload_as_needed, element N contains a REG rtx for the hard reg
71 into which pseudo reg N has been reloaded (perhaps for a previous insn). */
72 static rtx *reg_last_reload_reg;
74 /* Elt N nonzero if reg_last_reload_reg[N] has been set in this insn
75 for an output reload that stores into reg N. */
76 static char *reg_has_output_reload;
78 /* Indicates which hard regs are reload-registers for an output reload
79 in the current insn. */
80 static HARD_REG_SET reg_is_output_reload;
82 /* Element N is the constant value to which pseudo reg N is equivalent,
83 or zero if pseudo reg N is not equivalent to a constant.
84 find_reloads looks at this in order to replace pseudo reg N
85 with the constant it stands for. */
86 rtx *reg_equiv_constant;
88 /* Element N is a memory location to which pseudo reg N is equivalent,
89 prior to any register elimination (such as frame pointer to stack
90 pointer). Depending on whether or not it is a valid address, this value
91 is transferred to either reg_equiv_address or reg_equiv_mem. */
92 rtx *reg_equiv_memory_loc;
94 /* Element N is the address of stack slot to which pseudo reg N is equivalent.
95 This is used when the address is not valid as a memory address
96 (because its displacement is too big for the machine.) */
97 rtx *reg_equiv_address;
99 /* Element N is the memory slot to which pseudo reg N is equivalent,
100 or zero if pseudo reg N is not equivalent to a memory slot. */
103 /* Widest width in which each pseudo reg is referred to (via subreg). */
104 static int *reg_max_ref_width;
106 /* Element N is the insn that initialized reg N from its equivalent
107 constant or memory slot. */
108 static rtx *reg_equiv_init;
110 /* During reload_as_needed, element N contains the last pseudo regno
111 reloaded into the Nth reload register. This vector is in parallel
112 with spill_regs. If that pseudo reg occupied more than one register,
113 reg_reloaded_contents points to that pseudo for each spill register in
114 use; all of these must remain set for an inheritance to occur. */
115 static int reg_reloaded_contents[FIRST_PSEUDO_REGISTER];
117 /* During reload_as_needed, element N contains the insn for which
118 the Nth reload register was last used. This vector is in parallel
119 with spill_regs, and its contents are significant only when
120 reg_reloaded_contents is significant. */
121 static rtx reg_reloaded_insn[FIRST_PSEUDO_REGISTER];
123 /* Number of spill-regs so far; number of valid elements of spill_regs. */
126 /* In parallel with spill_regs, contains REG rtx's for those regs.
127 Holds the last rtx used for any given reg, or 0 if it has never
128 been used for spilling yet. This rtx is reused, provided it has
130 static rtx spill_reg_rtx[FIRST_PSEUDO_REGISTER];
132 /* In parallel with spill_regs, contains nonzero for a spill reg
133 that was stored after the last time it was used.
134 The precise value is the insn generated to do the store. */
135 static rtx spill_reg_store[FIRST_PSEUDO_REGISTER];
137 /* This table is the inverse mapping of spill_regs:
138 indexed by hard reg number,
139 it contains the position of that reg in spill_regs,
140 or -1 for something that is not in spill_regs. */
141 static short spill_reg_order[FIRST_PSEUDO_REGISTER];
143 /* This reg set indicates registers that may not be used for retrying global
144 allocation. The registers that may not be used include all spill registers
145 and the frame pointer (if we are using one). */
146 HARD_REG_SET forbidden_regs;
148 /* This reg set indicates registers that are not good for spill registers.
149 They will not be used to complete groups of spill registers. This includes
150 all fixed registers, registers that may be eliminated, and registers
151 explicitly used in the rtl.
153 (spill_reg_order prevents these registers from being used to start a
155 static HARD_REG_SET bad_spill_regs;
157 /* Describes order of use of registers for reloading
158 of spilled pseudo-registers. `spills' is the number of
159 elements that are actually valid; new ones are added at the end. */
160 static short spill_regs[FIRST_PSEUDO_REGISTER];
162 /* Describes order of preference for putting regs into spill_regs.
163 Contains the numbers of all the hard regs, in order most preferred first.
164 This order is different for each function.
165 It is set up by order_regs_for_reload.
166 Empty elements at the end contain -1. */
167 static short potential_reload_regs[FIRST_PSEUDO_REGISTER];
169 /* 1 for a hard register that appears explicitly in the rtl
170 (for example, function value registers, special registers
171 used by insns, structure value pointer registers). */
172 static char regs_explicitly_used[FIRST_PSEUDO_REGISTER];
174 /* Indicates if a register was counted against the need for
175 groups. 0 means it can count against max_nongroup instead. */
176 static HARD_REG_SET counted_for_groups;
178 /* Indicates if a register was counted against the need for
179 non-groups. 0 means it can become part of a new group.
180 During choose_reload_regs, 1 here means don't use this reg
181 as part of a group, even if it seems to be otherwise ok. */
182 static HARD_REG_SET counted_for_nongroups;
184 /* Nonzero if indirect addressing is supported on the machine; this means
185 that spilling (REG n) does not require reloading it into a register in
186 order to do (MEM (REG n)) or (MEM (PLUS (REG n) (CONST_INT c))). The
187 value indicates the level of indirect addressing supported, e.g., two
188 means that (MEM (MEM (REG n))) is also valid if (REG n) does not get
191 static char spill_indirect_levels;
193 /* Nonzero if indirect addressing is supported when the innermost MEM is
194 of the form (MEM (SYMBOL_REF sym)). It is assumed that the level to
195 which these are valid is the same as spill_indirect_levels, above. */
197 char indirect_symref_ok;
199 /* Nonzero if an address (plus (reg frame_pointer) (reg ...)) is valid. */
201 char double_reg_address_ok;
203 /* Record the stack slot for each spilled hard register. */
205 static rtx spill_stack_slot[FIRST_PSEUDO_REGISTER];
207 /* Width allocated so far for that stack slot. */
209 static int spill_stack_slot_width[FIRST_PSEUDO_REGISTER];
211 /* Indexed by register class and basic block number, nonzero if there is
212 any need for a spill register of that class in that basic block.
213 The pointer is 0 if we did stupid allocation and don't know
214 the structure of basic blocks. */
216 char *basic_block_needs[N_REG_CLASSES];
218 /* First uid used by insns created by reload in this function.
219 Used in find_equiv_reg. */
220 int reload_first_uid;
222 /* Flag set by local-alloc or global-alloc if anything is live in
223 a call-clobbered reg across calls. */
225 int caller_save_needed;
227 /* Set to 1 while reload_as_needed is operating.
228 Required by some machines to handle any generated moves differently. */
230 int reload_in_progress = 0;
232 /* These arrays record the insn_code of insns that may be needed to
233 perform input and output reloads of special objects. They provide a
234 place to pass a scratch register. */
236 enum insn_code reload_in_optab[NUM_MACHINE_MODES];
237 enum insn_code reload_out_optab[NUM_MACHINE_MODES];
239 /* This obstack is used for allocation of rtl during register elimination.
240 The allocated storage can be freed once find_reloads has processed the
243 struct obstack reload_obstack;
244 char *reload_firstobj;
246 #define obstack_chunk_alloc xmalloc
247 #define obstack_chunk_free free
249 /* List of labels that must never be deleted. */
250 extern rtx forced_labels;
252 /* This structure is used to record information about register eliminations.
253 Each array entry describes one possible way of eliminating a register
254 in favor of another. If there is more than one way of eliminating a
255 particular register, the most preferred should be specified first. */
257 static struct elim_table
259 int from; /* Register number to be eliminated. */
260 int to; /* Register number used as replacement. */
261 int initial_offset; /* Initial difference between values. */
262 int can_eliminate; /* Non-zero if this elimination can be done. */
263 int can_eliminate_previous; /* Value of CAN_ELIMINATE in previous scan over
264 insns made by reload. */
265 int offset; /* Current offset between the two regs. */
266 int max_offset; /* Maximum offset between the two regs. */
267 int previous_offset; /* Offset at end of previous insn. */
268 int ref_outside_mem; /* "to" has been referenced outside a MEM. */
269 rtx from_rtx; /* REG rtx for the register to be eliminated.
270 We cannot simply compare the number since
271 we might then spuriously replace a hard
272 register corresponding to a pseudo
273 assigned to the reg to be eliminated. */
274 rtx to_rtx; /* REG rtx for the replacement. */
277 /* If a set of eliminable registers was specified, define the table from it.
278 Otherwise, default to the normal case of the frame pointer being
279 replaced by the stack pointer. */
281 #ifdef ELIMINABLE_REGS
284 {{ FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM}};
287 #define NUM_ELIMINABLE_REGS (sizeof reg_eliminate / sizeof reg_eliminate[0])
289 /* Record the number of pending eliminations that have an offset not equal
290 to their initial offset. If non-zero, we use a new copy of each
291 replacement result in any insns encountered. */
292 static int num_not_at_initial_offset;
294 /* Count the number of registers that we may be able to eliminate. */
295 static int num_eliminable;
297 /* For each label, we record the offset of each elimination. If we reach
298 a label by more than one path and an offset differs, we cannot do the
299 elimination. This information is indexed by the number of the label.
300 The first table is an array of flags that records whether we have yet
301 encountered a label and the second table is an array of arrays, one
302 entry in the latter array for each elimination. */
304 static char *offsets_known_at;
305 static int (*offsets_at)[NUM_ELIMINABLE_REGS];
307 /* Number of labels in the current function. */
309 static int num_labels;
311 void mark_home_live ();
312 static void count_possible_groups ();
313 static int possible_group_p ();
314 static void scan_paradoxical_subregs ();
315 static void reload_as_needed ();
316 static int modes_equiv_for_class_p ();
317 static void alter_reg ();
318 static void delete_dead_insn ();
319 static void spill_failure ();
320 static int new_spill_reg();
321 static void set_label_offsets ();
322 static int eliminate_regs_in_insn ();
323 static void mark_not_eliminable ();
324 static int spill_hard_reg ();
325 static void choose_reload_regs ();
326 static void emit_reload_insns ();
327 static void delete_output_reload ();
328 static void forget_old_reloads_1 ();
329 static void order_regs_for_reload ();
330 static rtx inc_for_reload ();
331 static int constraint_accepts_reg_p ();
332 static int count_occurrences ();
334 extern void remove_death ();
335 extern rtx adj_offsettable_operand ();
336 extern rtx form_sum ();
343 /* Often (MEM (REG n)) is still valid even if (REG n) is put on the stack.
344 Set spill_indirect_levels to the number of levels such addressing is
345 permitted, zero if it is not permitted at all. */
348 = gen_rtx (MEM, Pmode,
349 gen_rtx (PLUS, Pmode,
350 gen_rtx (REG, Pmode, LAST_VIRTUAL_REGISTER + 1),
352 spill_indirect_levels = 0;
354 while (memory_address_p (QImode, tem))
356 spill_indirect_levels++;
357 tem = gen_rtx (MEM, Pmode, tem);
360 /* See if indirect addressing is valid for (MEM (SYMBOL_REF ...)). */
362 tem = gen_rtx (MEM, Pmode, gen_rtx (SYMBOL_REF, Pmode, "foo"));
363 indirect_symref_ok = memory_address_p (QImode, tem);
365 /* See if reg+reg is a valid (and offsettable) address. */
367 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
369 tem = gen_rtx (PLUS, Pmode,
370 gen_rtx (REG, Pmode, FRAME_POINTER_REGNUM),
371 gen_rtx (REG, Pmode, i));
372 /* This way, we make sure that reg+reg is an offsettable address. */
373 tem = plus_constant (tem, 4);
375 if (memory_address_p (QImode, tem))
377 double_reg_address_ok = 1;
382 /* Initialize obstack for our rtl allocation. */
383 gcc_obstack_init (&reload_obstack);
384 reload_firstobj = (char *) obstack_alloc (&reload_obstack, 0);
386 #ifdef HAVE_SECONDARY_RELOADS
388 /* Initialize the optabs for doing special input and output reloads. */
390 for (i = 0; i < NUM_MACHINE_MODES; i++)
391 reload_in_optab[i] = reload_out_optab[i] = CODE_FOR_nothing;
393 #ifdef HAVE_reload_inqi
394 if (HAVE_reload_inqi)
395 reload_in_optab[(int) QImode] = CODE_FOR_reload_inqi;
397 #ifdef HAVE_reload_inhi
398 if (HAVE_reload_inhi)
399 reload_in_optab[(int) HImode] = CODE_FOR_reload_inhi;
401 #ifdef HAVE_reload_insi
402 if (HAVE_reload_insi)
403 reload_in_optab[(int) SImode] = CODE_FOR_reload_insi;
405 #ifdef HAVE_reload_indi
406 if (HAVE_reload_indi)
407 reload_in_optab[(int) DImode] = CODE_FOR_reload_indi;
409 #ifdef HAVE_reload_inti
410 if (HAVE_reload_inti)
411 reload_in_optab[(int) TImode] = CODE_FOR_reload_inti;
413 #ifdef HAVE_reload_insf
414 if (HAVE_reload_insf)
415 reload_in_optab[(int) SFmode] = CODE_FOR_reload_insf;
417 #ifdef HAVE_reload_indf
418 if (HAVE_reload_indf)
419 reload_in_optab[(int) DFmode] = CODE_FOR_reload_indf;
421 #ifdef HAVE_reload_inxf
422 if (HAVE_reload_inxf)
423 reload_in_optab[(int) XFmode] = CODE_FOR_reload_inxf;
425 #ifdef HAVE_reload_intf
426 if (HAVE_reload_intf)
427 reload_in_optab[(int) TFmode] = CODE_FOR_reload_intf;
430 #ifdef HAVE_reload_outqi
431 if (HAVE_reload_outqi)
432 reload_out_optab[(int) QImode] = CODE_FOR_reload_outqi;
434 #ifdef HAVE_reload_outhi
435 if (HAVE_reload_outhi)
436 reload_out_optab[(int) HImode] = CODE_FOR_reload_outhi;
438 #ifdef HAVE_reload_outsi
439 if (HAVE_reload_outsi)
440 reload_out_optab[(int) SImode] = CODE_FOR_reload_outsi;
442 #ifdef HAVE_reload_outdi
443 if (HAVE_reload_outdi)
444 reload_out_optab[(int) DImode] = CODE_FOR_reload_outdi;
446 #ifdef HAVE_reload_outti
447 if (HAVE_reload_outti)
448 reload_out_optab[(int) TImode] = CODE_FOR_reload_outti;
450 #ifdef HAVE_reload_outsf
451 if (HAVE_reload_outsf)
452 reload_out_optab[(int) SFmode] = CODE_FOR_reload_outsf;
454 #ifdef HAVE_reload_outdf
455 if (HAVE_reload_outdf)
456 reload_out_optab[(int) DFmode] = CODE_FOR_reload_outdf;
458 #ifdef HAVE_reload_outxf
459 if (HAVE_reload_outxf)
460 reload_out_optab[(int) XFmode] = CODE_FOR_reload_outxf;
462 #ifdef HAVE_reload_outtf
463 if (HAVE_reload_outtf)
464 reload_out_optab[(int) TFmode] = CODE_FOR_reload_outtf;
467 #endif /* HAVE_SECONDARY_RELOADS */
471 /* Main entry point for the reload pass, and only entry point
474 FIRST is the first insn of the function being compiled.
476 GLOBAL nonzero means we were called from global_alloc
477 and should attempt to reallocate any pseudoregs that we
478 displace from hard regs we will use for reloads.
479 If GLOBAL is zero, we do not have enough information to do that,
480 so any pseudo reg that is spilled must go to the stack.
482 DUMPFILE is the global-reg debugging dump file stream, or 0.
483 If it is nonzero, messages are written to it to describe
484 which registers are seized as reload regs, which pseudo regs
485 are spilled from them, and where the pseudo regs are reallocated to.
487 Return value is nonzero if reload failed
488 and we must not do any more for this function. */
491 reload (first, global, dumpfile)
499 register struct elim_table *ep;
501 int something_changed;
502 int something_needs_reloads;
503 int something_needs_elimination;
504 int new_basic_block_needs;
505 enum reg_class caller_save_spill_class = NO_REGS;
506 int caller_save_group_size = 1;
508 /* Nonzero means we couldn't get enough spill regs. */
511 /* The basic block number currently being processed for INSN. */
514 /* Make sure even insns with volatile mem refs are recognizable. */
517 /* Enable find_equiv_reg to distinguish insns made by reload. */
518 reload_first_uid = get_max_uid ();
520 for (i = 0; i < N_REG_CLASSES; i++)
521 basic_block_needs[i] = 0;
523 #ifdef SECONDARY_MEMORY_NEEDED
524 /* Initialize the secondary memory table. */
525 clear_secondary_mem ();
528 /* Remember which hard regs appear explicitly
529 before we merge into `regs_ever_live' the ones in which
530 pseudo regs have been allocated. */
531 bcopy (regs_ever_live, regs_explicitly_used, sizeof regs_ever_live);
533 /* We don't have a stack slot for any spill reg yet. */
534 bzero (spill_stack_slot, sizeof spill_stack_slot);
535 bzero (spill_stack_slot_width, sizeof spill_stack_slot_width);
537 /* Initialize the save area information for caller-save, in case some
541 /* Compute which hard registers are now in use
542 as homes for pseudo registers.
543 This is done here rather than (eg) in global_alloc
544 because this point is reached even if not optimizing. */
546 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
549 /* Make sure that the last insn in the chain
550 is not something that needs reloading. */
551 emit_note (NULL_PTR, NOTE_INSN_DELETED);
553 /* Find all the pseudo registers that didn't get hard regs
554 but do have known equivalent constants or memory slots.
555 These include parameters (known equivalent to parameter slots)
556 and cse'd or loop-moved constant memory addresses.
558 Record constant equivalents in reg_equiv_constant
559 so they will be substituted by find_reloads.
560 Record memory equivalents in reg_mem_equiv so they can
561 be substituted eventually by altering the REG-rtx's. */
563 reg_equiv_constant = (rtx *) alloca (max_regno * sizeof (rtx));
564 bzero (reg_equiv_constant, max_regno * sizeof (rtx));
565 reg_equiv_memory_loc = (rtx *) alloca (max_regno * sizeof (rtx));
566 bzero (reg_equiv_memory_loc, max_regno * sizeof (rtx));
567 reg_equiv_mem = (rtx *) alloca (max_regno * sizeof (rtx));
568 bzero (reg_equiv_mem, max_regno * sizeof (rtx));
569 reg_equiv_init = (rtx *) alloca (max_regno * sizeof (rtx));
570 bzero (reg_equiv_init, max_regno * sizeof (rtx));
571 reg_equiv_address = (rtx *) alloca (max_regno * sizeof (rtx));
572 bzero (reg_equiv_address, max_regno * sizeof (rtx));
573 reg_max_ref_width = (int *) alloca (max_regno * sizeof (int));
574 bzero (reg_max_ref_width, max_regno * sizeof (int));
576 /* Look for REG_EQUIV notes; record what each pseudo is equivalent to.
577 Also find all paradoxical subregs
578 and find largest such for each pseudo. */
580 for (insn = first; insn; insn = NEXT_INSN (insn))
582 rtx set = single_set (insn);
584 if (set != 0 && GET_CODE (SET_DEST (set)) == REG)
586 rtx note = find_reg_note (insn, REG_EQUIV, NULL_RTX);
588 #ifdef LEGITIMATE_PIC_OPERAND_P
589 && (! CONSTANT_P (XEXP (note, 0)) || ! flag_pic
590 || LEGITIMATE_PIC_OPERAND_P (XEXP (note, 0)))
594 rtx x = XEXP (note, 0);
595 i = REGNO (SET_DEST (set));
596 if (i > LAST_VIRTUAL_REGISTER)
598 if (GET_CODE (x) == MEM)
599 reg_equiv_memory_loc[i] = x;
600 else if (CONSTANT_P (x))
602 if (LEGITIMATE_CONSTANT_P (x))
603 reg_equiv_constant[i] = x;
605 reg_equiv_memory_loc[i]
606 = force_const_mem (GET_MODE (SET_DEST (set)), x);
611 /* If this register is being made equivalent to a MEM
612 and the MEM is not SET_SRC, the equivalencing insn
613 is one with the MEM as a SET_DEST and it occurs later.
614 So don't mark this insn now. */
615 if (GET_CODE (x) != MEM
616 || rtx_equal_p (SET_SRC (set), x))
617 reg_equiv_init[i] = insn;
622 /* If this insn is setting a MEM from a register equivalent to it,
623 this is the equivalencing insn. */
624 else if (set && GET_CODE (SET_DEST (set)) == MEM
625 && GET_CODE (SET_SRC (set)) == REG
626 && reg_equiv_memory_loc[REGNO (SET_SRC (set))]
627 && rtx_equal_p (SET_DEST (set),
628 reg_equiv_memory_loc[REGNO (SET_SRC (set))]))
629 reg_equiv_init[REGNO (SET_SRC (set))] = insn;
631 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
632 scan_paradoxical_subregs (PATTERN (insn));
635 /* Does this function require a frame pointer? */
637 frame_pointer_needed = (! flag_omit_frame_pointer
638 #ifdef EXIT_IGNORE_STACK
639 /* ?? If EXIT_IGNORE_STACK is set, we will not save
640 and restore sp for alloca. So we can't eliminate
641 the frame pointer in that case. At some point,
642 we should improve this by emitting the
643 sp-adjusting insns for this case. */
644 || (current_function_calls_alloca
645 && EXIT_IGNORE_STACK)
647 || FRAME_POINTER_REQUIRED);
651 /* Initialize the table of registers to eliminate. The way we do this
652 depends on how the eliminable registers were defined. */
653 #ifdef ELIMINABLE_REGS
654 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
656 ep->can_eliminate = ep->can_eliminate_previous
657 = (CAN_ELIMINATE (ep->from, ep->to)
658 && (ep->from != FRAME_POINTER_REGNUM || ! frame_pointer_needed));
661 reg_eliminate[0].can_eliminate = reg_eliminate[0].can_eliminate_previous
662 = ! frame_pointer_needed;
665 /* Count the number of eliminable registers and build the FROM and TO
666 REG rtx's. Note that code in gen_rtx will cause, e.g.,
667 gen_rtx (REG, Pmode, STACK_POINTER_REGNUM) to equal stack_pointer_rtx.
668 We depend on this. */
669 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
671 num_eliminable += ep->can_eliminate;
672 ep->from_rtx = gen_rtx (REG, Pmode, ep->from);
673 ep->to_rtx = gen_rtx (REG, Pmode, ep->to);
676 num_labels = max_label_num () - get_first_label_num ();
678 /* Allocate the tables used to store offset information at labels. */
679 offsets_known_at = (char *) alloca (num_labels);
681 = (int (*)[NUM_ELIMINABLE_REGS])
682 alloca (num_labels * NUM_ELIMINABLE_REGS * sizeof (int));
684 offsets_known_at -= get_first_label_num ();
685 offsets_at -= get_first_label_num ();
687 /* Alter each pseudo-reg rtx to contain its hard reg number.
688 Assign stack slots to the pseudos that lack hard regs or equivalents.
689 Do not touch virtual registers. */
691 for (i = LAST_VIRTUAL_REGISTER + 1; i < max_regno; i++)
694 /* Round size of stack frame to BIGGEST_ALIGNMENT. This must be done here
695 because the stack size may be a part of the offset computation for
696 register elimination. */
697 assign_stack_local (BLKmode, 0, 0);
699 /* If we have some registers we think can be eliminated, scan all insns to
700 see if there is an insn that sets one of these registers to something
701 other than itself plus a constant. If so, the register cannot be
702 eliminated. Doing this scan here eliminates an extra pass through the
703 main reload loop in the most common case where register elimination
705 for (insn = first; insn && num_eliminable; insn = NEXT_INSN (insn))
706 if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN
707 || GET_CODE (insn) == CALL_INSN)
708 note_stores (PATTERN (insn), mark_not_eliminable);
710 #ifndef REGISTER_CONSTRAINTS
711 /* If all the pseudo regs have hard regs,
712 except for those that are never referenced,
713 we know that no reloads are needed. */
714 /* But that is not true if there are register constraints, since
715 in that case some pseudos might be in the wrong kind of hard reg. */
717 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
718 if (reg_renumber[i] == -1 && reg_n_refs[i] != 0)
721 if (i == max_regno && num_eliminable == 0 && ! caller_save_needed)
725 /* Compute the order of preference for hard registers to spill.
726 Store them by decreasing preference in potential_reload_regs. */
728 order_regs_for_reload ();
730 /* So far, no hard regs have been spilled. */
732 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
733 spill_reg_order[i] = -1;
735 /* On most machines, we can't use any register explicitly used in the
736 rtl as a spill register. But on some, we have to. Those will have
737 taken care to keep the life of hard regs as short as possible. */
739 #ifdef SMALL_REGISTER_CLASSES
740 CLEAR_HARD_REG_SET (forbidden_regs);
742 COPY_HARD_REG_SET (forbidden_regs, bad_spill_regs);
745 /* Spill any hard regs that we know we can't eliminate. */
746 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
747 if (! ep->can_eliminate)
749 spill_hard_reg (ep->from, global, dumpfile, 1);
750 regs_ever_live[ep->from] = 1;
754 for (i = 0; i < N_REG_CLASSES; i++)
756 basic_block_needs[i] = (char *)alloca (n_basic_blocks);
757 bzero (basic_block_needs[i], n_basic_blocks);
760 /* From now on, we need to emit any moves without making new pseudos. */
761 reload_in_progress = 1;
763 /* This loop scans the entire function each go-round
764 and repeats until one repetition spills no additional hard regs. */
766 /* This flag is set when a pseudo reg is spilled,
767 to require another pass. Note that getting an additional reload
768 reg does not necessarily imply any pseudo reg was spilled;
769 sometimes we find a reload reg that no pseudo reg was allocated in. */
770 something_changed = 1;
771 /* This flag is set if there are any insns that require reloading. */
772 something_needs_reloads = 0;
773 /* This flag is set if there are any insns that require register
775 something_needs_elimination = 0;
776 while (something_changed)
780 /* For each class, number of reload regs needed in that class.
781 This is the maximum over all insns of the needs in that class
782 of the individual insn. */
783 int max_needs[N_REG_CLASSES];
784 /* For each class, size of group of consecutive regs
785 that is needed for the reloads of this class. */
786 int group_size[N_REG_CLASSES];
787 /* For each class, max number of consecutive groups needed.
788 (Each group contains group_size[CLASS] consecutive registers.) */
789 int max_groups[N_REG_CLASSES];
790 /* For each class, max number needed of regs that don't belong
791 to any of the groups. */
792 int max_nongroups[N_REG_CLASSES];
793 /* For each class, the machine mode which requires consecutive
794 groups of regs of that class.
795 If two different modes ever require groups of one class,
796 they must be the same size and equally restrictive for that class,
797 otherwise we can't handle the complexity. */
798 enum machine_mode group_mode[N_REG_CLASSES];
799 /* Record the insn where each maximum need is first found. */
800 rtx max_needs_insn[N_REG_CLASSES];
801 rtx max_groups_insn[N_REG_CLASSES];
802 rtx max_nongroups_insn[N_REG_CLASSES];
804 int starting_frame_size = get_frame_size ();
805 static char *reg_class_names[] = REG_CLASS_NAMES;
807 something_changed = 0;
808 bzero (max_needs, sizeof max_needs);
809 bzero (max_groups, sizeof max_groups);
810 bzero (max_nongroups, sizeof max_nongroups);
811 bzero (max_needs_insn, sizeof max_needs_insn);
812 bzero (max_groups_insn, sizeof max_groups_insn);
813 bzero (max_nongroups_insn, sizeof max_nongroups_insn);
814 bzero (group_size, sizeof group_size);
815 for (i = 0; i < N_REG_CLASSES; i++)
816 group_mode[i] = VOIDmode;
818 /* Keep track of which basic blocks are needing the reloads. */
821 /* Remember whether any element of basic_block_needs
822 changes from 0 to 1 in this pass. */
823 new_basic_block_needs = 0;
825 /* Reset all offsets on eliminable registers to their initial values. */
826 #ifdef ELIMINABLE_REGS
827 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
829 INITIAL_ELIMINATION_OFFSET (ep->from, ep->to, ep->initial_offset);
830 ep->previous_offset = ep->offset
831 = ep->max_offset = ep->initial_offset;
834 #ifdef INITIAL_FRAME_POINTER_OFFSET
835 INITIAL_FRAME_POINTER_OFFSET (reg_eliminate[0].initial_offset);
837 if (!FRAME_POINTER_REQUIRED)
839 reg_eliminate[0].initial_offset = 0;
841 reg_eliminate[0].previous_offset = reg_eliminate[0].max_offset
842 = reg_eliminate[0].offset = reg_eliminate[0].initial_offset;
845 num_not_at_initial_offset = 0;
847 bzero (&offsets_known_at[get_first_label_num ()], num_labels);
849 /* Set a known offset for each forced label to be at the initial offset
850 of each elimination. We do this because we assume that all
851 computed jumps occur from a location where each elimination is
852 at its initial offset. */
854 for (x = forced_labels; x; x = XEXP (x, 1))
856 set_label_offsets (XEXP (x, 0), NULL_RTX, 1);
858 /* For each pseudo register that has an equivalent location defined,
859 try to eliminate any eliminable registers (such as the frame pointer)
860 assuming initial offsets for the replacement register, which
863 If the resulting location is directly addressable, substitute
864 the MEM we just got directly for the old REG.
866 If it is not addressable but is a constant or the sum of a hard reg
867 and constant, it is probably not addressable because the constant is
868 out of range, in that case record the address; we will generate
869 hairy code to compute the address in a register each time it is
872 If the location is not addressable, but does not have one of the
873 above forms, assign a stack slot. We have to do this to avoid the
874 potential of producing lots of reloads if, e.g., a location involves
875 a pseudo that didn't get a hard register and has an equivalent memory
876 location that also involves a pseudo that didn't get a hard register.
878 Perhaps at some point we will improve reload_when_needed handling
879 so this problem goes away. But that's very hairy. */
881 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
882 if (reg_renumber[i] < 0 && reg_equiv_memory_loc[i])
884 rtx x = eliminate_regs (reg_equiv_memory_loc[i], 0, NULL_RTX);
886 if (strict_memory_address_p (GET_MODE (regno_reg_rtx[i]),
888 reg_equiv_mem[i] = x, reg_equiv_address[i] = 0;
889 else if (CONSTANT_P (XEXP (x, 0))
890 || (GET_CODE (XEXP (x, 0)) == PLUS
891 && GET_CODE (XEXP (XEXP (x, 0), 0)) == REG
892 && (REGNO (XEXP (XEXP (x, 0), 0))
893 < FIRST_PSEUDO_REGISTER)
894 && CONSTANT_P (XEXP (XEXP (x, 0), 1))))
895 reg_equiv_address[i] = XEXP (x, 0), reg_equiv_mem[i] = 0;
898 /* Make a new stack slot. Then indicate that something
899 changed so we go back and recompute offsets for
900 eliminable registers because the allocation of memory
901 below might change some offset. reg_equiv_{mem,address}
902 will be set up for this pseudo on the next pass around
904 reg_equiv_memory_loc[i] = 0;
905 reg_equiv_init[i] = 0;
907 something_changed = 1;
911 /* If we allocated another pseudo to the stack, redo elimination
913 if (something_changed)
916 /* If caller-saves needs a group, initialize the group to include
917 the size and mode required for caller-saves. */
919 if (caller_save_group_size > 1)
921 group_mode[(int) caller_save_spill_class] = Pmode;
922 group_size[(int) caller_save_spill_class] = caller_save_group_size;
925 /* Compute the most additional registers needed by any instruction.
926 Collect information separately for each class of regs. */
928 for (insn = first; insn; insn = NEXT_INSN (insn))
930 if (global && this_block + 1 < n_basic_blocks
931 && insn == basic_block_head[this_block+1])
934 /* If this is a label, a JUMP_INSN, or has REG_NOTES (which
935 might include REG_LABEL), we need to see what effects this
936 has on the known offsets at labels. */
938 if (GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == JUMP_INSN
939 || (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
940 && REG_NOTES (insn) != 0))
941 set_label_offsets (insn, insn, 0);
943 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
945 /* Nonzero means don't use a reload reg that overlaps
946 the place where a function value can be returned. */
947 rtx avoid_return_reg = 0;
949 rtx old_body = PATTERN (insn);
950 int old_code = INSN_CODE (insn);
951 rtx old_notes = REG_NOTES (insn);
952 int did_elimination = 0;
954 /* Initially, count RELOAD_OTHER reloads.
955 Later, merge in the other kinds. */
956 int insn_needs[N_REG_CLASSES];
957 int insn_groups[N_REG_CLASSES];
958 int insn_total_groups = 0;
960 /* Count RELOAD_FOR_INPUT_RELOAD_ADDRESS reloads. */
961 int insn_needs_for_inputs[N_REG_CLASSES];
962 int insn_groups_for_inputs[N_REG_CLASSES];
963 int insn_total_groups_for_inputs = 0;
965 /* Count RELOAD_FOR_OUTPUT_RELOAD_ADDRESS reloads. */
966 int insn_needs_for_outputs[N_REG_CLASSES];
967 int insn_groups_for_outputs[N_REG_CLASSES];
968 int insn_total_groups_for_outputs = 0;
970 /* Count RELOAD_FOR_OPERAND_ADDRESS reloads. */
971 int insn_needs_for_operands[N_REG_CLASSES];
972 int insn_groups_for_operands[N_REG_CLASSES];
973 int insn_total_groups_for_operands = 0;
975 #if 0 /* This wouldn't work nowadays, since optimize_bit_field
976 looks for non-strict memory addresses. */
977 /* Optimization: a bit-field instruction whose field
978 happens to be a byte or halfword in memory
979 can be changed to a move instruction. */
981 if (GET_CODE (PATTERN (insn)) == SET)
983 rtx dest = SET_DEST (PATTERN (insn));
984 rtx src = SET_SRC (PATTERN (insn));
986 if (GET_CODE (dest) == ZERO_EXTRACT
987 || GET_CODE (dest) == SIGN_EXTRACT)
988 optimize_bit_field (PATTERN (insn), insn, reg_equiv_mem);
989 if (GET_CODE (src) == ZERO_EXTRACT
990 || GET_CODE (src) == SIGN_EXTRACT)
991 optimize_bit_field (PATTERN (insn), insn, reg_equiv_mem);
995 /* If needed, eliminate any eliminable registers. */
997 did_elimination = eliminate_regs_in_insn (insn, 0);
999 #ifdef SMALL_REGISTER_CLASSES
1000 /* Set avoid_return_reg if this is an insn
1001 that might use the value of a function call. */
1002 if (GET_CODE (insn) == CALL_INSN)
1004 if (GET_CODE (PATTERN (insn)) == SET)
1005 after_call = SET_DEST (PATTERN (insn));
1006 else if (GET_CODE (PATTERN (insn)) == PARALLEL
1007 && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET)
1008 after_call = SET_DEST (XVECEXP (PATTERN (insn), 0, 0));
1012 else if (after_call != 0
1013 && !(GET_CODE (PATTERN (insn)) == SET
1014 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx))
1016 if (reg_mentioned_p (after_call, PATTERN (insn)))
1017 avoid_return_reg = after_call;
1020 #endif /* SMALL_REGISTER_CLASSES */
1022 /* Analyze the instruction. */
1023 find_reloads (insn, 0, spill_indirect_levels, global,
1026 /* Remember for later shortcuts which insns had any reloads or
1027 register eliminations.
1029 One might think that it would be worthwhile to mark insns
1030 that need register replacements but not reloads, but this is
1031 not safe because find_reloads may do some manipulation of
1032 the insn (such as swapping commutative operands), which would
1033 be lost when we restore the old pattern after register
1034 replacement. So the actions of find_reloads must be redone in
1035 subsequent passes or in reload_as_needed.
1037 However, it is safe to mark insns that need reloads
1038 but not register replacement. */
1040 PUT_MODE (insn, (did_elimination ? QImode
1041 : n_reloads ? HImode
1044 /* Discard any register replacements done. */
1045 if (did_elimination)
1047 obstack_free (&reload_obstack, reload_firstobj);
1048 PATTERN (insn) = old_body;
1049 INSN_CODE (insn) = old_code;
1050 REG_NOTES (insn) = old_notes;
1051 something_needs_elimination = 1;
1054 /* If this insn has no reloads, we need not do anything except
1055 in the case of a CALL_INSN when we have caller-saves and
1056 caller-save needs reloads. */
1059 && ! (GET_CODE (insn) == CALL_INSN
1060 && caller_save_spill_class != NO_REGS))
1063 something_needs_reloads = 1;
1065 for (i = 0; i < N_REG_CLASSES; i++)
1067 insn_needs[i] = 0, insn_groups[i] = 0;
1068 insn_needs_for_inputs[i] = 0, insn_groups_for_inputs[i] = 0;
1069 insn_needs_for_outputs[i] = 0, insn_groups_for_outputs[i] = 0;
1070 insn_needs_for_operands[i] = 0, insn_groups_for_operands[i] = 0;
1073 /* Count each reload once in every class
1074 containing the reload's own class. */
1076 for (i = 0; i < n_reloads; i++)
1078 register enum reg_class *p;
1079 enum reg_class class = reload_reg_class[i];
1081 enum machine_mode mode;
1084 int *this_total_groups;
1086 /* Don't count the dummy reloads, for which one of the
1087 regs mentioned in the insn can be used for reloading.
1088 Don't count optional reloads.
1089 Don't count reloads that got combined with others. */
1090 if (reload_reg_rtx[i] != 0
1091 || reload_optional[i] != 0
1092 || (reload_out[i] == 0 && reload_in[i] == 0
1093 && ! reload_secondary_p[i]))
1096 /* Show that a reload register of this class is needed
1097 in this basic block. We do not use insn_needs and
1098 insn_groups because they are overly conservative for
1100 if (global && ! basic_block_needs[(int) class][this_block])
1102 basic_block_needs[(int) class][this_block] = 1;
1103 new_basic_block_needs = 1;
1106 /* Decide which time-of-use to count this reload for. */
1107 switch (reload_when_needed[i])
1110 case RELOAD_FOR_OUTPUT:
1111 case RELOAD_FOR_INPUT:
1112 this_needs = insn_needs;
1113 this_groups = insn_groups;
1114 this_total_groups = &insn_total_groups;
1117 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
1118 this_needs = insn_needs_for_inputs;
1119 this_groups = insn_groups_for_inputs;
1120 this_total_groups = &insn_total_groups_for_inputs;
1123 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
1124 this_needs = insn_needs_for_outputs;
1125 this_groups = insn_groups_for_outputs;
1126 this_total_groups = &insn_total_groups_for_outputs;
1129 case RELOAD_FOR_OPERAND_ADDRESS:
1130 this_needs = insn_needs_for_operands;
1131 this_groups = insn_groups_for_operands;
1132 this_total_groups = &insn_total_groups_for_operands;
1136 mode = reload_inmode[i];
1137 if (GET_MODE_SIZE (reload_outmode[i]) > GET_MODE_SIZE (mode))
1138 mode = reload_outmode[i];
1139 size = CLASS_MAX_NREGS (class, mode);
1142 enum machine_mode other_mode, allocate_mode;
1144 /* Count number of groups needed separately from
1145 number of individual regs needed. */
1146 this_groups[(int) class]++;
1147 p = reg_class_superclasses[(int) class];
1148 while (*p != LIM_REG_CLASSES)
1149 this_groups[(int) *p++]++;
1150 (*this_total_groups)++;
1152 /* Record size and mode of a group of this class. */
1153 /* If more than one size group is needed,
1154 make all groups the largest needed size. */
1155 if (group_size[(int) class] < size)
1157 other_mode = group_mode[(int) class];
1158 allocate_mode = mode;
1160 group_size[(int) class] = size;
1161 group_mode[(int) class] = mode;
1166 allocate_mode = group_mode[(int) class];
1169 /* Crash if two dissimilar machine modes both need
1170 groups of consecutive regs of the same class. */
1172 if (other_mode != VOIDmode
1173 && other_mode != allocate_mode
1174 && ! modes_equiv_for_class_p (allocate_mode,
1181 this_needs[(int) class] += 1;
1182 p = reg_class_superclasses[(int) class];
1183 while (*p != LIM_REG_CLASSES)
1184 this_needs[(int) *p++] += 1;
1190 /* All reloads have been counted for this insn;
1191 now merge the various times of use.
1192 This sets insn_needs, etc., to the maximum total number
1193 of registers needed at any point in this insn. */
1195 for (i = 0; i < N_REG_CLASSES; i++)
1198 this_max = insn_needs_for_inputs[i];
1199 if (insn_needs_for_outputs[i] > this_max)
1200 this_max = insn_needs_for_outputs[i];
1201 if (insn_needs_for_operands[i] > this_max)
1202 this_max = insn_needs_for_operands[i];
1203 insn_needs[i] += this_max;
1204 this_max = insn_groups_for_inputs[i];
1205 if (insn_groups_for_outputs[i] > this_max)
1206 this_max = insn_groups_for_outputs[i];
1207 if (insn_groups_for_operands[i] > this_max)
1208 this_max = insn_groups_for_operands[i];
1209 insn_groups[i] += this_max;
1212 insn_total_groups += MAX (insn_total_groups_for_inputs,
1213 MAX (insn_total_groups_for_outputs,
1214 insn_total_groups_for_operands));
1216 /* If this is a CALL_INSN and caller-saves will need
1217 a spill register, act as if the spill register is
1218 needed for this insn. However, the spill register
1219 can be used by any reload of this insn, so we only
1220 need do something if no need for that class has
1223 The assumption that every CALL_INSN will trigger a
1224 caller-save is highly conservative, however, the number
1225 of cases where caller-saves will need a spill register but
1226 a block containing a CALL_INSN won't need a spill register
1227 of that class should be quite rare.
1229 If a group is needed, the size and mode of the group will
1230 have been set up at the beginning of this loop. */
1232 if (GET_CODE (insn) == CALL_INSN
1233 && caller_save_spill_class != NO_REGS)
1235 int *caller_save_needs
1236 = (caller_save_group_size > 1 ? insn_groups : insn_needs);
1238 if (caller_save_needs[(int) caller_save_spill_class] == 0)
1240 register enum reg_class *p
1241 = reg_class_superclasses[(int) caller_save_spill_class];
1243 caller_save_needs[(int) caller_save_spill_class]++;
1245 while (*p != LIM_REG_CLASSES)
1246 caller_save_needs[(int) *p++] += 1;
1249 if (caller_save_group_size > 1)
1250 insn_total_groups = MAX (insn_total_groups, 1);
1253 /* Show that this basic block will need a register of
1257 && ! (basic_block_needs[(int) caller_save_spill_class]
1260 basic_block_needs[(int) caller_save_spill_class]
1262 new_basic_block_needs = 1;
1266 #ifdef SMALL_REGISTER_CLASSES
1267 /* If this insn stores the value of a function call,
1268 and that value is in a register that has been spilled,
1269 and if the insn needs a reload in a class
1270 that might use that register as the reload register,
1271 then add add an extra need in that class.
1272 This makes sure we have a register available that does
1273 not overlap the return value. */
1274 if (avoid_return_reg)
1276 int regno = REGNO (avoid_return_reg);
1278 = HARD_REGNO_NREGS (regno, GET_MODE (avoid_return_reg));
1281 for (r = regno; r < regno + nregs; r++)
1282 if (spill_reg_order[r] >= 0)
1283 for (i = 0; i < N_REG_CLASSES; i++)
1284 if (TEST_HARD_REG_BIT (reg_class_contents[i], r))
1286 if (insn_needs[i] > 0)
1288 if (insn_groups[i] > 0
1295 #endif /* SMALL_REGISTER_CLASSES */
1297 /* For each class, collect maximum need of any insn. */
1299 for (i = 0; i < N_REG_CLASSES; i++)
1301 if (max_needs[i] < insn_needs[i])
1303 max_needs[i] = insn_needs[i];
1304 max_needs_insn[i] = insn;
1306 if (max_groups[i] < insn_groups[i])
1308 max_groups[i] = insn_groups[i];
1309 max_groups_insn[i] = insn;
1311 if (insn_total_groups > 0)
1312 if (max_nongroups[i] < insn_needs[i])
1314 max_nongroups[i] = insn_needs[i];
1315 max_nongroups_insn[i] = insn;
1319 /* Note that there is a continue statement above. */
1322 /* If we allocated any new memory locations, make another pass
1323 since it might have changed elimination offsets. */
1324 if (starting_frame_size != get_frame_size ())
1325 something_changed = 1;
1328 for (i = 0; i < N_REG_CLASSES; i++)
1330 if (max_needs[i] > 0)
1332 ";; Need %d reg%s of class %s (for insn %d).\n",
1333 max_needs[i], max_needs[i] == 1 ? "" : "s",
1334 reg_class_names[i], INSN_UID (max_needs_insn[i]));
1335 if (max_nongroups[i] > 0)
1337 ";; Need %d nongroup reg%s of class %s (for insn %d).\n",
1338 max_nongroups[i], max_nongroups[i] == 1 ? "" : "s",
1339 reg_class_names[i], INSN_UID (max_nongroups_insn[i]));
1340 if (max_groups[i] > 0)
1342 ";; Need %d group%s (%smode) of class %s (for insn %d).\n",
1343 max_groups[i], max_groups[i] == 1 ? "" : "s",
1344 mode_name[(int) group_mode[i]],
1345 reg_class_names[i], INSN_UID (max_groups_insn[i]));
1348 /* If we have caller-saves, set up the save areas and see if caller-save
1349 will need a spill register. */
1351 if (caller_save_needed
1352 && ! setup_save_areas (&something_changed)
1353 && caller_save_spill_class == NO_REGS)
1355 /* The class we will need depends on whether the machine
1356 supports the sum of two registers for an address; see
1357 find_address_reloads for details. */
1359 caller_save_spill_class
1360 = double_reg_address_ok ? INDEX_REG_CLASS : BASE_REG_CLASS;
1361 caller_save_group_size
1362 = CLASS_MAX_NREGS (caller_save_spill_class, Pmode);
1363 something_changed = 1;
1366 /* Now deduct from the needs for the registers already
1367 available (already spilled). */
1369 CLEAR_HARD_REG_SET (counted_for_groups);
1370 CLEAR_HARD_REG_SET (counted_for_nongroups);
1372 /* First find all regs alone in their class
1373 and count them (if desired) for non-groups.
1374 We would be screwed if a group took the only reg in a class
1375 for which a non-group reload is needed.
1376 (Note there is still a bug; if a class has 2 regs,
1377 both could be stolen by groups and we would lose the same way.
1378 With luck, no machine will need a nongroup in a 2-reg class.) */
1380 for (i = 0; i < n_spills; i++)
1382 register enum reg_class *p;
1383 class = (int) REGNO_REG_CLASS (spill_regs[i]);
1385 if (reg_class_size[class] == 1 && max_nongroups[class] > 0)
1388 p = reg_class_superclasses[class];
1389 while (*p != LIM_REG_CLASSES)
1390 max_needs[(int) *p++]--;
1392 SET_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]);
1393 max_nongroups[class]--;
1394 p = reg_class_superclasses[class];
1395 while (*p != LIM_REG_CLASSES)
1397 if (max_nongroups[(int) *p] > 0)
1398 SET_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]);
1399 max_nongroups[(int) *p++]--;
1404 /* Now find all consecutive groups of spilled registers
1405 and mark each group off against the need for such groups.
1406 But don't count them against ordinary need, yet. */
1408 count_possible_groups (group_size, group_mode, max_groups);
1410 /* Now count all spill regs against the individual need,
1411 This includes those counted above for groups,
1412 but not those previously counted for nongroups.
1414 Those that weren't counted_for_groups can also count against
1415 the not-in-group need. */
1417 for (i = 0; i < n_spills; i++)
1419 register enum reg_class *p;
1420 class = (int) REGNO_REG_CLASS (spill_regs[i]);
1422 /* Those counted at the beginning shouldn't be counted twice. */
1423 if (! TEST_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]))
1426 p = reg_class_superclasses[class];
1427 while (*p != LIM_REG_CLASSES)
1428 max_needs[(int) *p++]--;
1430 if (! TEST_HARD_REG_BIT (counted_for_groups, spill_regs[i]))
1432 if (max_nongroups[class] > 0)
1433 SET_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]);
1434 max_nongroups[class]--;
1435 p = reg_class_superclasses[class];
1436 while (*p != LIM_REG_CLASSES)
1438 if (max_nongroups[(int) *p] > 0)
1439 SET_HARD_REG_BIT (counted_for_nongroups,
1441 max_nongroups[(int) *p++]--;
1447 /* See if anything that happened changes which eliminations are valid.
1448 For example, on the Sparc, whether or not the frame pointer can
1449 be eliminated can depend on what registers have been used. We need
1450 not check some conditions again (such as flag_omit_frame_pointer)
1451 since they can't have changed. */
1453 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
1454 if ((ep->from == FRAME_POINTER_REGNUM && FRAME_POINTER_REQUIRED)
1455 #ifdef ELIMINABLE_REGS
1456 || ! CAN_ELIMINATE (ep->from, ep->to)
1459 ep->can_eliminate = 0;
1461 /* Look for the case where we have discovered that we can't replace
1462 register A with register B and that means that we will now be
1463 trying to replace register A with register C. This means we can
1464 no longer replace register C with register B and we need to disable
1465 such an elimination, if it exists. This occurs often with A == ap,
1466 B == sp, and C == fp. */
1468 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
1470 struct elim_table *op;
1471 register int new_to = -1;
1473 if (! ep->can_eliminate && ep->can_eliminate_previous)
1475 /* Find the current elimination for ep->from, if there is a
1477 for (op = reg_eliminate;
1478 op < ®_eliminate[NUM_ELIMINABLE_REGS]; op++)
1479 if (op->from == ep->from && op->can_eliminate)
1485 /* See if there is an elimination of NEW_TO -> EP->TO. If so,
1487 for (op = reg_eliminate;
1488 op < ®_eliminate[NUM_ELIMINABLE_REGS]; op++)
1489 if (op->from == new_to && op->to == ep->to)
1490 op->can_eliminate = 0;
1494 /* See if any registers that we thought we could eliminate the previous
1495 time are no longer eliminable. If so, something has changed and we
1496 must spill the register. Also, recompute the number of eliminable
1497 registers and see if the frame pointer is needed; it is if there is
1498 no elimination of the frame pointer that we can perform. */
1500 frame_pointer_needed = 1;
1501 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
1503 if (ep->can_eliminate && ep->from == FRAME_POINTER_REGNUM)
1504 frame_pointer_needed = 0;
1506 if (! ep->can_eliminate && ep->can_eliminate_previous)
1508 ep->can_eliminate_previous = 0;
1509 spill_hard_reg (ep->from, global, dumpfile, 1);
1510 regs_ever_live[ep->from] = 1;
1511 something_changed = 1;
1516 /* If all needs are met, we win. */
1518 for (i = 0; i < N_REG_CLASSES; i++)
1519 if (max_needs[i] > 0 || max_groups[i] > 0 || max_nongroups[i] > 0)
1521 if (i == N_REG_CLASSES && !new_basic_block_needs && ! something_changed)
1524 /* Not all needs are met; must spill more hard regs. */
1526 /* If any element of basic_block_needs changed from 0 to 1,
1527 re-spill all the regs already spilled. This may spill
1528 additional pseudos that didn't spill before. */
1530 if (new_basic_block_needs)
1531 for (i = 0; i < n_spills; i++)
1533 |= spill_hard_reg (spill_regs[i], global, dumpfile, 0);
1535 /* Now find more reload regs to satisfy the remaining need
1536 Do it by ascending class number, since otherwise a reg
1537 might be spilled for a big class and might fail to count
1538 for a smaller class even though it belongs to that class.
1540 Count spilled regs in `spills', and add entries to
1541 `spill_regs' and `spill_reg_order'.
1543 ??? Note there is a problem here.
1544 When there is a need for a group in a high-numbered class,
1545 and also need for non-group regs that come from a lower class,
1546 the non-group regs are chosen first. If there aren't many regs,
1547 they might leave no room for a group.
1549 This was happening on the 386. To fix it, we added the code
1550 that calls possible_group_p, so that the lower class won't
1551 break up the last possible group.
1553 Really fixing the problem would require changes above
1554 in counting the regs already spilled, and in choose_reload_regs.
1555 It might be hard to avoid introducing bugs there. */
1557 for (class = 0; class < N_REG_CLASSES; class++)
1559 /* First get the groups of registers.
1560 If we got single registers first, we might fragment
1562 while (max_groups[class] > 0)
1564 /* If any single spilled regs happen to form groups,
1565 count them now. Maybe we don't really need
1566 to spill another group. */
1567 count_possible_groups (group_size, group_mode, max_groups);
1569 /* Groups of size 2 (the only groups used on most machines)
1570 are treated specially. */
1571 if (group_size[class] == 2)
1573 /* First, look for a register that will complete a group. */
1574 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1576 int j = potential_reload_regs[i];
1578 if (j >= 0 && ! TEST_HARD_REG_BIT (bad_spill_regs, j)
1580 ((j > 0 && (other = j - 1, spill_reg_order[other] >= 0)
1581 && TEST_HARD_REG_BIT (reg_class_contents[class], j)
1582 && TEST_HARD_REG_BIT (reg_class_contents[class], other)
1583 && HARD_REGNO_MODE_OK (other, group_mode[class])
1584 && ! TEST_HARD_REG_BIT (counted_for_nongroups,
1586 /* We don't want one part of another group.
1587 We could get "two groups" that overlap! */
1588 && ! TEST_HARD_REG_BIT (counted_for_groups, other))
1590 (j < FIRST_PSEUDO_REGISTER - 1
1591 && (other = j + 1, spill_reg_order[other] >= 0)
1592 && TEST_HARD_REG_BIT (reg_class_contents[class], j)
1593 && TEST_HARD_REG_BIT (reg_class_contents[class], other)
1594 && HARD_REGNO_MODE_OK (j, group_mode[class])
1595 && ! TEST_HARD_REG_BIT (counted_for_nongroups,
1597 && ! TEST_HARD_REG_BIT (counted_for_groups,
1600 register enum reg_class *p;
1602 /* We have found one that will complete a group,
1603 so count off one group as provided. */
1604 max_groups[class]--;
1605 p = reg_class_superclasses[class];
1606 while (*p != LIM_REG_CLASSES)
1607 max_groups[(int) *p++]--;
1609 /* Indicate both these regs are part of a group. */
1610 SET_HARD_REG_BIT (counted_for_groups, j);
1611 SET_HARD_REG_BIT (counted_for_groups, other);
1615 /* We can't complete a group, so start one. */
1616 if (i == FIRST_PSEUDO_REGISTER)
1617 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1619 int j = potential_reload_regs[i];
1620 if (j >= 0 && j + 1 < FIRST_PSEUDO_REGISTER
1621 && spill_reg_order[j] < 0 && spill_reg_order[j + 1] < 0
1622 && TEST_HARD_REG_BIT (reg_class_contents[class], j)
1623 && TEST_HARD_REG_BIT (reg_class_contents[class], j + 1)
1624 && HARD_REGNO_MODE_OK (j, group_mode[class])
1625 && ! TEST_HARD_REG_BIT (counted_for_nongroups,
1630 /* I should be the index in potential_reload_regs
1631 of the new reload reg we have found. */
1633 if (i >= FIRST_PSEUDO_REGISTER)
1635 /* There are no groups left to spill. */
1636 spill_failure (max_groups_insn[class]);
1642 |= new_spill_reg (i, class, max_needs, NULL_PTR,
1647 /* For groups of more than 2 registers,
1648 look for a sufficient sequence of unspilled registers,
1649 and spill them all at once. */
1650 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1652 int j = potential_reload_regs[i];
1655 && j + group_size[class] <= FIRST_PSEUDO_REGISTER
1656 && HARD_REGNO_MODE_OK (j, group_mode[class]))
1658 /* Check each reg in the sequence. */
1659 for (k = 0; k < group_size[class]; k++)
1660 if (! (spill_reg_order[j + k] < 0
1661 && ! TEST_HARD_REG_BIT (bad_spill_regs, j + k)
1662 && TEST_HARD_REG_BIT (reg_class_contents[class], j + k)))
1664 /* We got a full sequence, so spill them all. */
1665 if (k == group_size[class])
1667 register enum reg_class *p;
1668 for (k = 0; k < group_size[class]; k++)
1671 SET_HARD_REG_BIT (counted_for_groups, j + k);
1672 for (idx = 0; idx < FIRST_PSEUDO_REGISTER; idx++)
1673 if (potential_reload_regs[idx] == j + k)
1676 |= new_spill_reg (idx, class,
1677 max_needs, NULL_PTR,
1681 /* We have found one that will complete a group,
1682 so count off one group as provided. */
1683 max_groups[class]--;
1684 p = reg_class_superclasses[class];
1685 while (*p != LIM_REG_CLASSES)
1686 max_groups[(int) *p++]--;
1692 /* We couldn't find any registers for this reload.
1693 Avoid going into an infinite loop. */
1694 if (i >= FIRST_PSEUDO_REGISTER)
1696 /* There are no groups left. */
1697 spill_failure (max_groups_insn[class]);
1704 /* Now similarly satisfy all need for single registers. */
1706 while (max_needs[class] > 0 || max_nongroups[class] > 0)
1708 /* Consider the potential reload regs that aren't
1709 yet in use as reload regs, in order of preference.
1710 Find the most preferred one that's in this class. */
1712 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1713 if (potential_reload_regs[i] >= 0
1714 && TEST_HARD_REG_BIT (reg_class_contents[class],
1715 potential_reload_regs[i])
1716 /* If this reg will not be available for groups,
1717 pick one that does not foreclose possible groups.
1718 This is a kludge, and not very general,
1719 but it should be sufficient to make the 386 work,
1720 and the problem should not occur on machines with
1722 && (max_nongroups[class] == 0
1723 || possible_group_p (potential_reload_regs[i], max_groups)))
1726 /* If we couldn't get a register, try to get one even if we
1727 might foreclose possible groups. This may cause problems
1728 later, but that's better than aborting now, since it is
1729 possible that we will, in fact, be able to form the needed
1730 group even with this allocation. */
1732 if (i >= FIRST_PSEUDO_REGISTER
1733 && (asm_noperands (max_needs[class] > 0
1734 ? max_needs_insn[class]
1735 : max_nongroups_insn[class])
1737 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1738 if (potential_reload_regs[i] >= 0
1739 && TEST_HARD_REG_BIT (reg_class_contents[class],
1740 potential_reload_regs[i]))
1743 /* I should be the index in potential_reload_regs
1744 of the new reload reg we have found. */
1746 if (i >= FIRST_PSEUDO_REGISTER)
1748 /* There are no possible registers left to spill. */
1749 spill_failure (max_needs[class] > 0 ? max_needs_insn[class]
1750 : max_nongroups_insn[class]);
1756 |= new_spill_reg (i, class, max_needs, max_nongroups,
1762 /* If global-alloc was run, notify it of any register eliminations we have
1765 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
1766 if (ep->can_eliminate)
1767 mark_elimination (ep->from, ep->to);
1769 /* Insert code to save and restore call-clobbered hard regs
1770 around calls. Tell if what mode to use so that we will process
1771 those insns in reload_as_needed if we have to. */
1773 if (caller_save_needed)
1774 save_call_clobbered_regs (num_eliminable ? QImode
1775 : caller_save_spill_class != NO_REGS ? HImode
1778 /* If a pseudo has no hard reg, delete the insns that made the equivalence.
1779 If that insn didn't set the register (i.e., it copied the register to
1780 memory), just delete that insn instead of the equivalencing insn plus
1781 anything now dead. If we call delete_dead_insn on that insn, we may
1782 delete the insn that actually sets the register if the register die
1783 there and that is incorrect. */
1785 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
1786 if (reg_renumber[i] < 0 && reg_equiv_init[i] != 0
1787 && GET_CODE (reg_equiv_init[i]) != NOTE)
1789 if (reg_set_p (regno_reg_rtx[i], PATTERN (reg_equiv_init[i])))
1790 delete_dead_insn (reg_equiv_init[i]);
1793 PUT_CODE (reg_equiv_init[i], NOTE);
1794 NOTE_SOURCE_FILE (reg_equiv_init[i]) = 0;
1795 NOTE_LINE_NUMBER (reg_equiv_init[i]) = NOTE_INSN_DELETED;
1799 /* Use the reload registers where necessary
1800 by generating move instructions to move the must-be-register
1801 values into or out of the reload registers. */
1803 if (something_needs_reloads || something_needs_elimination
1804 || (caller_save_needed && num_eliminable)
1805 || caller_save_spill_class != NO_REGS)
1806 reload_as_needed (first, global);
1808 /* If we were able to eliminate the frame pointer, show that it is no
1809 longer live at the start of any basic block. If it ls live by
1810 virtue of being in a pseudo, that pseudo will be marked live
1811 and hence the frame pointer will be known to be live via that
1814 if (! frame_pointer_needed)
1815 for (i = 0; i < n_basic_blocks; i++)
1816 basic_block_live_at_start[i][FRAME_POINTER_REGNUM / REGSET_ELT_BITS]
1817 &= ~ ((REGSET_ELT_TYPE) 1 << (FRAME_POINTER_REGNUM % REGSET_ELT_BITS));
1819 reload_in_progress = 0;
1821 /* Come here (with failure set nonzero) if we can't get enough spill regs
1822 and we decide not to abort about it. */
1825 /* Now eliminate all pseudo regs by modifying them into
1826 their equivalent memory references.
1827 The REG-rtx's for the pseudos are modified in place,
1828 so all insns that used to refer to them now refer to memory.
1830 For a reg that has a reg_equiv_address, all those insns
1831 were changed by reloading so that no insns refer to it any longer;
1832 but the DECL_RTL of a variable decl may refer to it,
1833 and if so this causes the debugging info to mention the variable. */
1835 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
1839 if (reg_equiv_mem[i])
1841 addr = XEXP (reg_equiv_mem[i], 0);
1842 in_struct = MEM_IN_STRUCT_P (reg_equiv_mem[i]);
1844 if (reg_equiv_address[i])
1845 addr = reg_equiv_address[i];
1848 if (reg_renumber[i] < 0)
1850 rtx reg = regno_reg_rtx[i];
1851 XEXP (reg, 0) = addr;
1852 REG_USERVAR_P (reg) = 0;
1853 MEM_IN_STRUCT_P (reg) = in_struct;
1854 PUT_CODE (reg, MEM);
1856 else if (reg_equiv_mem[i])
1857 XEXP (reg_equiv_mem[i], 0) = addr;
1861 #ifdef PRESERVE_DEATH_INFO_REGNO_P
1862 /* Make a pass over all the insns and remove death notes for things that
1863 are no longer registers or no longer die in the insn (e.g., an input
1864 and output pseudo being tied). */
1866 for (insn = first; insn; insn = NEXT_INSN (insn))
1867 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
1871 for (note = REG_NOTES (insn); note; note = next)
1873 next = XEXP (note, 1);
1874 if (REG_NOTE_KIND (note) == REG_DEAD
1875 && (GET_CODE (XEXP (note, 0)) != REG
1876 || reg_set_p (XEXP (note, 0), PATTERN (insn))))
1877 remove_note (insn, note);
1882 /* Indicate that we no longer have known memory locations or constants. */
1883 reg_equiv_constant = 0;
1884 reg_equiv_memory_loc = 0;
1889 /* Nonzero if, after spilling reg REGNO for non-groups,
1890 it will still be possible to find a group if we still need one. */
1893 possible_group_p (regno, max_groups)
1898 int class = (int) NO_REGS;
1900 for (i = 0; i < (int) N_REG_CLASSES; i++)
1901 if (max_groups[i] > 0)
1907 if (class == (int) NO_REGS)
1910 /* Consider each pair of consecutive registers. */
1911 for (i = 0; i < FIRST_PSEUDO_REGISTER - 1; i++)
1913 /* Ignore pairs that include reg REGNO. */
1914 if (i == regno || i + 1 == regno)
1917 /* Ignore pairs that are outside the class that needs the group.
1918 ??? Here we fail to handle the case where two different classes
1919 independently need groups. But this never happens with our
1920 current machine descriptions. */
1921 if (! (TEST_HARD_REG_BIT (reg_class_contents[class], i)
1922 && TEST_HARD_REG_BIT (reg_class_contents[class], i + 1)))
1925 /* A pair of consecutive regs we can still spill does the trick. */
1926 if (spill_reg_order[i] < 0 && spill_reg_order[i + 1] < 0
1927 && ! TEST_HARD_REG_BIT (bad_spill_regs, i)
1928 && ! TEST_HARD_REG_BIT (bad_spill_regs, i + 1))
1931 /* A pair of one already spilled and one we can spill does it
1932 provided the one already spilled is not otherwise reserved. */
1933 if (spill_reg_order[i] < 0
1934 && ! TEST_HARD_REG_BIT (bad_spill_regs, i)
1935 && spill_reg_order[i + 1] >= 0
1936 && ! TEST_HARD_REG_BIT (counted_for_groups, i + 1)
1937 && ! TEST_HARD_REG_BIT (counted_for_nongroups, i + 1))
1939 if (spill_reg_order[i + 1] < 0
1940 && ! TEST_HARD_REG_BIT (bad_spill_regs, i + 1)
1941 && spill_reg_order[i] >= 0
1942 && ! TEST_HARD_REG_BIT (counted_for_groups, i)
1943 && ! TEST_HARD_REG_BIT (counted_for_nongroups, i))
1950 /* Count any groups that can be formed from the registers recently spilled.
1951 This is done class by class, in order of ascending class number. */
1954 count_possible_groups (group_size, group_mode, max_groups)
1955 int *group_size, *max_groups;
1956 enum machine_mode *group_mode;
1959 /* Now find all consecutive groups of spilled registers
1960 and mark each group off against the need for such groups.
1961 But don't count them against ordinary need, yet. */
1963 for (i = 0; i < N_REG_CLASSES; i++)
1964 if (group_size[i] > 1)
1966 char regmask[FIRST_PSEUDO_REGISTER];
1969 bzero (regmask, sizeof regmask);
1970 /* Make a mask of all the regs that are spill regs in class I. */
1971 for (j = 0; j < n_spills; j++)
1972 if (TEST_HARD_REG_BIT (reg_class_contents[i], spill_regs[j])
1973 && ! TEST_HARD_REG_BIT (counted_for_groups, spill_regs[j])
1974 && ! TEST_HARD_REG_BIT (counted_for_nongroups,
1976 regmask[spill_regs[j]] = 1;
1977 /* Find each consecutive group of them. */
1978 for (j = 0; j < FIRST_PSEUDO_REGISTER && max_groups[i] > 0; j++)
1979 if (regmask[j] && j + group_size[i] <= FIRST_PSEUDO_REGISTER
1980 /* Next line in case group-mode for this class
1981 demands an even-odd pair. */
1982 && HARD_REGNO_MODE_OK (j, group_mode[i]))
1985 for (k = 1; k < group_size[i]; k++)
1986 if (! regmask[j + k])
1988 if (k == group_size[i])
1990 /* We found a group. Mark it off against this class's
1991 need for groups, and against each superclass too. */
1992 register enum reg_class *p;
1994 p = reg_class_superclasses[i];
1995 while (*p != LIM_REG_CLASSES)
1996 max_groups[(int) *p++]--;
1997 /* Don't count these registers again. */
1998 for (k = 0; k < group_size[i]; k++)
1999 SET_HARD_REG_BIT (counted_for_groups, j + k);
2001 /* Skip to the last reg in this group. When j is incremented
2002 above, it will then point to the first reg of the next
2010 /* ALLOCATE_MODE is a register mode that needs to be reloaded. OTHER_MODE is
2011 another mode that needs to be reloaded for the same register class CLASS.
2012 If any reg in CLASS allows ALLOCATE_MODE but not OTHER_MODE, fail.
2013 ALLOCATE_MODE will never be smaller than OTHER_MODE.
2015 This code used to also fail if any reg in CLASS allows OTHER_MODE but not
2016 ALLOCATE_MODE. This test is unnecessary, because we will never try to put
2017 something of mode ALLOCATE_MODE into an OTHER_MODE register. Testing this
2018 causes unnecessary failures on machines requiring alignment of register
2019 groups when the two modes are different sizes, because the larger mode has
2020 more strict alignment rules than the smaller mode. */
2023 modes_equiv_for_class_p (allocate_mode, other_mode, class)
2024 enum machine_mode allocate_mode, other_mode;
2025 enum reg_class class;
2028 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
2030 if (TEST_HARD_REG_BIT (reg_class_contents[(int) class], regno)
2031 && HARD_REGNO_MODE_OK (regno, allocate_mode)
2032 && ! HARD_REGNO_MODE_OK (regno, other_mode))
2038 /* Handle the failure to find a register to spill.
2039 INSN should be one of the insns which needed this particular spill reg. */
2042 spill_failure (insn)
2045 if (asm_noperands (PATTERN (insn)) >= 0)
2046 error_for_asm (insn, "`asm' needs too many reloads");
2051 /* Add a new register to the tables of available spill-registers
2052 (as well as spilling all pseudos allocated to the register).
2053 I is the index of this register in potential_reload_regs.
2054 CLASS is the regclass whose need is being satisfied.
2055 MAX_NEEDS and MAX_NONGROUPS are the vectors of needs,
2056 so that this register can count off against them.
2057 MAX_NONGROUPS is 0 if this register is part of a group.
2058 GLOBAL and DUMPFILE are the same as the args that `reload' got. */
2061 new_spill_reg (i, class, max_needs, max_nongroups, global, dumpfile)
2069 register enum reg_class *p;
2071 int regno = potential_reload_regs[i];
2073 if (i >= FIRST_PSEUDO_REGISTER)
2074 abort (); /* Caller failed to find any register. */
2076 if (fixed_regs[regno] || TEST_HARD_REG_BIT (forbidden_regs, regno))
2077 fatal ("fixed or forbidden register was spilled.\n\
2078 This may be due to a compiler bug or to impossible asm statements.");
2080 /* Make reg REGNO an additional reload reg. */
2082 potential_reload_regs[i] = -1;
2083 spill_regs[n_spills] = regno;
2084 spill_reg_order[regno] = n_spills;
2086 fprintf (dumpfile, "Spilling reg %d.\n", spill_regs[n_spills]);
2088 /* Clear off the needs we just satisfied. */
2091 p = reg_class_superclasses[class];
2092 while (*p != LIM_REG_CLASSES)
2093 max_needs[(int) *p++]--;
2095 if (max_nongroups && max_nongroups[class] > 0)
2097 SET_HARD_REG_BIT (counted_for_nongroups, regno);
2098 max_nongroups[class]--;
2099 p = reg_class_superclasses[class];
2100 while (*p != LIM_REG_CLASSES)
2101 max_nongroups[(int) *p++]--;
2104 /* Spill every pseudo reg that was allocated to this reg
2105 or to something that overlaps this reg. */
2107 val = spill_hard_reg (spill_regs[n_spills], global, dumpfile, 0);
2109 /* If there are some registers still to eliminate and this register
2110 wasn't ever used before, additional stack space may have to be
2111 allocated to store this register. Thus, we may have changed the offset
2112 between the stack and frame pointers, so mark that something has changed.
2113 (If new pseudos were spilled, thus requiring more space, VAL would have
2114 been set non-zero by the call to spill_hard_reg above since additional
2115 reloads may be needed in that case.
2117 One might think that we need only set VAL to 1 if this is a call-used
2118 register. However, the set of registers that must be saved by the
2119 prologue is not identical to the call-used set. For example, the
2120 register used by the call insn for the return PC is a call-used register,
2121 but must be saved by the prologue. */
2122 if (num_eliminable && ! regs_ever_live[spill_regs[n_spills]])
2125 regs_ever_live[spill_regs[n_spills]] = 1;
2131 /* Delete an unneeded INSN and any previous insns who sole purpose is loading
2132 data that is dead in INSN. */
2135 delete_dead_insn (insn)
2138 rtx prev = prev_real_insn (insn);
2141 /* If the previous insn sets a register that dies in our insn, delete it
2143 if (prev && GET_CODE (PATTERN (prev)) == SET
2144 && (prev_dest = SET_DEST (PATTERN (prev)), GET_CODE (prev_dest) == REG)
2145 && reg_mentioned_p (prev_dest, PATTERN (insn))
2146 && find_regno_note (insn, REG_DEAD, REGNO (prev_dest)))
2147 delete_dead_insn (prev);
2149 PUT_CODE (insn, NOTE);
2150 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
2151 NOTE_SOURCE_FILE (insn) = 0;
2154 /* Modify the home of pseudo-reg I.
2155 The new home is present in reg_renumber[I].
2157 FROM_REG may be the hard reg that the pseudo-reg is being spilled from;
2158 or it may be -1, meaning there is none or it is not relevant.
2159 This is used so that all pseudos spilled from a given hard reg
2160 can share one stack slot. */
2163 alter_reg (i, from_reg)
2167 /* When outputting an inline function, this can happen
2168 for a reg that isn't actually used. */
2169 if (regno_reg_rtx[i] == 0)
2172 /* If the reg got changed to a MEM at rtl-generation time,
2174 if (GET_CODE (regno_reg_rtx[i]) != REG)
2177 /* Modify the reg-rtx to contain the new hard reg
2178 number or else to contain its pseudo reg number. */
2179 REGNO (regno_reg_rtx[i])
2180 = reg_renumber[i] >= 0 ? reg_renumber[i] : i;
2182 /* If we have a pseudo that is needed but has no hard reg or equivalent,
2183 allocate a stack slot for it. */
2185 if (reg_renumber[i] < 0
2186 && reg_n_refs[i] > 0
2187 && reg_equiv_constant[i] == 0
2188 && reg_equiv_memory_loc[i] == 0)
2191 int inherent_size = PSEUDO_REGNO_BYTES (i);
2192 int total_size = MAX (inherent_size, reg_max_ref_width[i]);
2195 /* Each pseudo reg has an inherent size which comes from its own mode,
2196 and a total size which provides room for paradoxical subregs
2197 which refer to the pseudo reg in wider modes.
2199 We can use a slot already allocated if it provides both
2200 enough inherent space and enough total space.
2201 Otherwise, we allocate a new slot, making sure that it has no less
2202 inherent space, and no less total space, then the previous slot. */
2205 /* No known place to spill from => no slot to reuse. */
2206 x = assign_stack_local (GET_MODE (regno_reg_rtx[i]), total_size, -1);
2207 #if BYTES_BIG_ENDIAN
2208 /* Cancel the big-endian correction done in assign_stack_local.
2209 Get the address of the beginning of the slot.
2210 This is so we can do a big-endian correction unconditionally
2212 adjust = inherent_size - total_size;
2215 /* Reuse a stack slot if possible. */
2216 else if (spill_stack_slot[from_reg] != 0
2217 && spill_stack_slot_width[from_reg] >= total_size
2218 && (GET_MODE_SIZE (GET_MODE (spill_stack_slot[from_reg]))
2220 x = spill_stack_slot[from_reg];
2221 /* Allocate a bigger slot. */
2224 /* Compute maximum size needed, both for inherent size
2225 and for total size. */
2226 enum machine_mode mode = GET_MODE (regno_reg_rtx[i]);
2227 if (spill_stack_slot[from_reg])
2229 if (GET_MODE_SIZE (GET_MODE (spill_stack_slot[from_reg]))
2231 mode = GET_MODE (spill_stack_slot[from_reg]);
2232 if (spill_stack_slot_width[from_reg] > total_size)
2233 total_size = spill_stack_slot_width[from_reg];
2235 /* Make a slot with that size. */
2236 x = assign_stack_local (mode, total_size, -1);
2237 #if BYTES_BIG_ENDIAN
2238 /* Cancel the big-endian correction done in assign_stack_local.
2239 Get the address of the beginning of the slot.
2240 This is so we can do a big-endian correction unconditionally
2242 adjust = GET_MODE_SIZE (mode) - total_size;
2244 spill_stack_slot[from_reg] = x;
2245 spill_stack_slot_width[from_reg] = total_size;
2248 #if BYTES_BIG_ENDIAN
2249 /* On a big endian machine, the "address" of the slot
2250 is the address of the low part that fits its inherent mode. */
2251 if (inherent_size < total_size)
2252 adjust += (total_size - inherent_size);
2253 #endif /* BYTES_BIG_ENDIAN */
2255 /* If we have any adjustment to make, or if the stack slot is the
2256 wrong mode, make a new stack slot. */
2257 if (adjust != 0 || GET_MODE (x) != GET_MODE (regno_reg_rtx[i]))
2259 x = gen_rtx (MEM, GET_MODE (regno_reg_rtx[i]),
2260 plus_constant (XEXP (x, 0), adjust));
2261 RTX_UNCHANGING_P (x) = RTX_UNCHANGING_P (regno_reg_rtx[i]);
2264 /* Save the stack slot for later. */
2265 reg_equiv_memory_loc[i] = x;
2269 /* Mark the slots in regs_ever_live for the hard regs
2270 used by pseudo-reg number REGNO. */
2273 mark_home_live (regno)
2276 register int i, lim;
2277 i = reg_renumber[regno];
2280 lim = i + HARD_REGNO_NREGS (i, PSEUDO_REGNO_MODE (regno));
2282 regs_ever_live[i++] = 1;
2285 /* This function handles the tracking of elimination offsets around branches.
2287 X is a piece of RTL being scanned.
2289 INSN is the insn that it came from, if any.
2291 INITIAL_P is non-zero if we are to set the offset to be the initial
2292 offset and zero if we are setting the offset of the label to be the
2296 set_label_offsets (x, insn, initial_p)
2301 enum rtx_code code = GET_CODE (x);
2304 struct elim_table *p;
2309 if (LABEL_REF_NONLOCAL_P (x))
2314 /* ... fall through ... */
2317 /* If we know nothing about this label, set the desired offsets. Note
2318 that this sets the offset at a label to be the offset before a label
2319 if we don't know anything about the label. This is not correct for
2320 the label after a BARRIER, but is the best guess we can make. If
2321 we guessed wrong, we will suppress an elimination that might have
2322 been possible had we been able to guess correctly. */
2324 if (! offsets_known_at[CODE_LABEL_NUMBER (x)])
2326 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
2327 offsets_at[CODE_LABEL_NUMBER (x)][i]
2328 = (initial_p ? reg_eliminate[i].initial_offset
2329 : reg_eliminate[i].offset);
2330 offsets_known_at[CODE_LABEL_NUMBER (x)] = 1;
2333 /* Otherwise, if this is the definition of a label and it is
2334 preceded by a BARRIER, set our offsets to the known offset of
2338 && (tem = prev_nonnote_insn (insn)) != 0
2339 && GET_CODE (tem) == BARRIER)
2341 num_not_at_initial_offset = 0;
2342 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
2344 reg_eliminate[i].offset = reg_eliminate[i].previous_offset
2345 = offsets_at[CODE_LABEL_NUMBER (x)][i];
2346 if (reg_eliminate[i].can_eliminate
2347 && (reg_eliminate[i].offset
2348 != reg_eliminate[i].initial_offset))
2349 num_not_at_initial_offset++;
2354 /* If neither of the above cases is true, compare each offset
2355 with those previously recorded and suppress any eliminations
2356 where the offsets disagree. */
2358 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
2359 if (offsets_at[CODE_LABEL_NUMBER (x)][i]
2360 != (initial_p ? reg_eliminate[i].initial_offset
2361 : reg_eliminate[i].offset))
2362 reg_eliminate[i].can_eliminate = 0;
2367 set_label_offsets (PATTERN (insn), insn, initial_p);
2369 /* ... fall through ... */
2373 /* Any labels mentioned in REG_LABEL notes can be branched to indirectly
2374 and hence must have all eliminations at their initial offsets. */
2375 for (tem = REG_NOTES (x); tem; tem = XEXP (tem, 1))
2376 if (REG_NOTE_KIND (tem) == REG_LABEL)
2377 set_label_offsets (XEXP (tem, 0), insn, 1);
2382 /* Each of the labels in the address vector must be at their initial
2383 offsets. We want the first first for ADDR_VEC and the second
2384 field for ADDR_DIFF_VEC. */
2386 for (i = 0; i < XVECLEN (x, code == ADDR_DIFF_VEC); i++)
2387 set_label_offsets (XVECEXP (x, code == ADDR_DIFF_VEC, i),
2392 /* We only care about setting PC. If the source is not RETURN,
2393 IF_THEN_ELSE, or a label, disable any eliminations not at
2394 their initial offsets. Similarly if any arm of the IF_THEN_ELSE
2395 isn't one of those possibilities. For branches to a label,
2396 call ourselves recursively.
2398 Note that this can disable elimination unnecessarily when we have
2399 a non-local goto since it will look like a non-constant jump to
2400 someplace in the current function. This isn't a significant
2401 problem since such jumps will normally be when all elimination
2402 pairs are back to their initial offsets. */
2404 if (SET_DEST (x) != pc_rtx)
2407 switch (GET_CODE (SET_SRC (x)))
2414 set_label_offsets (XEXP (SET_SRC (x), 0), insn, initial_p);
2418 tem = XEXP (SET_SRC (x), 1);
2419 if (GET_CODE (tem) == LABEL_REF)
2420 set_label_offsets (XEXP (tem, 0), insn, initial_p);
2421 else if (GET_CODE (tem) != PC && GET_CODE (tem) != RETURN)
2424 tem = XEXP (SET_SRC (x), 2);
2425 if (GET_CODE (tem) == LABEL_REF)
2426 set_label_offsets (XEXP (tem, 0), insn, initial_p);
2427 else if (GET_CODE (tem) != PC && GET_CODE (tem) != RETURN)
2432 /* If we reach here, all eliminations must be at their initial
2433 offset because we are doing a jump to a variable address. */
2434 for (p = reg_eliminate; p < ®_eliminate[NUM_ELIMINABLE_REGS]; p++)
2435 if (p->offset != p->initial_offset)
2436 p->can_eliminate = 0;
2440 /* Used for communication between the next two function to properly share
2441 the vector for an ASM_OPERANDS. */
2443 static struct rtvec_def *old_asm_operands_vec, *new_asm_operands_vec;
2445 /* Scan X and replace any eliminable registers (such as fp) with a
2446 replacement (such as sp), plus an offset.
2448 MEM_MODE is the mode of an enclosing MEM. We need this to know how
2449 much to adjust a register for, e.g., PRE_DEC. Also, if we are inside a
2450 MEM, we are allowed to replace a sum of a register and the constant zero
2451 with the register, which we cannot do outside a MEM. In addition, we need
2452 to record the fact that a register is referenced outside a MEM.
2454 If INSN is nonzero, it is the insn containing X. If we replace a REG
2455 in a SET_DEST with an equivalent MEM and INSN is non-zero, write a
2456 CLOBBER of the pseudo after INSN so find_equiv_regs will know that
2457 that the REG is being modified.
2459 If we see a modification to a register we know about, take the
2460 appropriate action (see case SET, below).
2462 REG_EQUIV_MEM and REG_EQUIV_ADDRESS contain address that have had
2463 replacements done assuming all offsets are at their initial values. If
2464 they are not, or if REG_EQUIV_ADDRESS is nonzero for a pseudo we
2465 encounter, return the actual location so that find_reloads will do
2466 the proper thing. */
2469 eliminate_regs (x, mem_mode, insn)
2471 enum machine_mode mem_mode;
2474 enum rtx_code code = GET_CODE (x);
2475 struct elim_table *ep;
2500 /* First handle the case where we encounter a bare register that
2501 is eliminable. Replace it with a PLUS. */
2502 if (regno < FIRST_PSEUDO_REGISTER)
2504 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS];
2506 if (ep->from_rtx == x && ep->can_eliminate)
2509 ep->ref_outside_mem = 1;
2510 return plus_constant (ep->to_rtx, ep->previous_offset);
2514 else if (reg_equiv_memory_loc && reg_equiv_memory_loc[regno]
2515 && (reg_equiv_address[regno] || num_not_at_initial_offset))
2517 /* In this case, find_reloads would attempt to either use an
2518 incorrect address (if something is not at its initial offset)
2519 or substitute an replaced address into an insn (which loses
2520 if the offset is changed by some later action). So we simply
2521 return the replaced stack slot (assuming it is changed by
2522 elimination) and ignore the fact that this is actually a
2523 reference to the pseudo. Ensure we make a copy of the
2524 address in case it is shared. */
2525 new = eliminate_regs (reg_equiv_memory_loc[regno],
2526 mem_mode, NULL_RTX);
2527 if (new != reg_equiv_memory_loc[regno])
2528 return copy_rtx (new);
2533 /* If this is the sum of an eliminable register and a constant, rework
2535 if (GET_CODE (XEXP (x, 0)) == REG
2536 && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER
2537 && CONSTANT_P (XEXP (x, 1)))
2539 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS];
2541 if (ep->from_rtx == XEXP (x, 0) && ep->can_eliminate)
2544 ep->ref_outside_mem = 1;
2546 /* The only time we want to replace a PLUS with a REG (this
2547 occurs when the constant operand of the PLUS is the negative
2548 of the offset) is when we are inside a MEM. We won't want
2549 to do so at other times because that would change the
2550 structure of the insn in a way that reload can't handle.
2551 We special-case the commonest situation in
2552 eliminate_regs_in_insn, so just replace a PLUS with a
2553 PLUS here, unless inside a MEM. */
2554 if (mem_mode != 0 && GET_CODE (XEXP (x, 1)) == CONST_INT
2555 && INTVAL (XEXP (x, 1)) == - ep->previous_offset)
2558 return gen_rtx (PLUS, Pmode, ep->to_rtx,
2559 plus_constant (XEXP (x, 1),
2560 ep->previous_offset));
2563 /* If the register is not eliminable, we are done since the other
2564 operand is a constant. */
2568 /* If this is part of an address, we want to bring any constant to the
2569 outermost PLUS. We will do this by doing register replacement in
2570 our operands and seeing if a constant shows up in one of them.
2572 We assume here this is part of an address (or a "load address" insn)
2573 since an eliminable register is not likely to appear in any other
2576 If we have (plus (eliminable) (reg)), we want to produce
2577 (plus (plus (replacement) (reg) (const))). If this was part of a
2578 normal add insn, (plus (replacement) (reg)) will be pushed as a
2579 reload. This is the desired action. */
2582 rtx new0 = eliminate_regs (XEXP (x, 0), mem_mode, NULL_RTX);
2583 rtx new1 = eliminate_regs (XEXP (x, 1), mem_mode, NULL_RTX);
2585 if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1))
2587 /* If one side is a PLUS and the other side is a pseudo that
2588 didn't get a hard register but has a reg_equiv_constant,
2589 we must replace the constant here since it may no longer
2590 be in the position of any operand. */
2591 if (GET_CODE (new0) == PLUS && GET_CODE (new1) == REG
2592 && REGNO (new1) >= FIRST_PSEUDO_REGISTER
2593 && reg_renumber[REGNO (new1)] < 0
2594 && reg_equiv_constant != 0
2595 && reg_equiv_constant[REGNO (new1)] != 0)
2596 new1 = reg_equiv_constant[REGNO (new1)];
2597 else if (GET_CODE (new1) == PLUS && GET_CODE (new0) == REG
2598 && REGNO (new0) >= FIRST_PSEUDO_REGISTER
2599 && reg_renumber[REGNO (new0)] < 0
2600 && reg_equiv_constant[REGNO (new0)] != 0)
2601 new0 = reg_equiv_constant[REGNO (new0)];
2603 new = form_sum (new0, new1);
2605 /* As above, if we are not inside a MEM we do not want to
2606 turn a PLUS into something else. We might try to do so here
2607 for an addition of 0 if we aren't optimizing. */
2608 if (! mem_mode && GET_CODE (new) != PLUS)
2609 return gen_rtx (PLUS, GET_MODE (x), new, const0_rtx);
2617 /* If we have something in XEXP (x, 0), the usual case, eliminate it. */
2620 new = eliminate_regs (XEXP (x, 0), mem_mode, NULL_RTX);
2621 if (new != XEXP (x, 0))
2622 x = gen_rtx (EXPR_LIST, REG_NOTE_KIND (x), new, XEXP (x, 1));
2625 /* ... fall through ... */
2628 /* Now do eliminations in the rest of the chain. If this was
2629 an EXPR_LIST, this might result in allocating more memory than is
2630 strictly needed, but it simplifies the code. */
2633 new = eliminate_regs (XEXP (x, 1), mem_mode, NULL_RTX);
2634 if (new != XEXP (x, 1))
2635 return gen_rtx (INSN_LIST, GET_MODE (x), XEXP (x, 0), new);
2643 case DIV: case UDIV:
2644 case MOD: case UMOD:
2645 case AND: case IOR: case XOR:
2646 case LSHIFT: case ASHIFT: case ROTATE:
2647 case ASHIFTRT: case LSHIFTRT: case ROTATERT:
2649 case GE: case GT: case GEU: case GTU:
2650 case LE: case LT: case LEU: case LTU:
2652 rtx new0 = eliminate_regs (XEXP (x, 0), mem_mode, NULL_RTX);
2654 = XEXP (x, 1) ? eliminate_regs (XEXP (x, 1), mem_mode, NULL_RTX) : 0;
2656 if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1))
2657 return gen_rtx (code, GET_MODE (x), new0, new1);
2665 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
2666 if (ep->to_rtx == XEXP (x, 0))
2668 if (code == PRE_DEC || code == POST_DEC)
2669 ep->offset += GET_MODE_SIZE (mem_mode);
2671 ep->offset -= GET_MODE_SIZE (mem_mode);
2674 /* Fall through to generic unary operation case. */
2676 case STRICT_LOW_PART:
2678 case SIGN_EXTEND: case ZERO_EXTEND:
2679 case TRUNCATE: case FLOAT_EXTEND: case FLOAT_TRUNCATE:
2680 case FLOAT: case FIX:
2681 case UNSIGNED_FIX: case UNSIGNED_FLOAT:
2685 new = eliminate_regs (XEXP (x, 0), mem_mode, NULL_RTX);
2686 if (new != XEXP (x, 0))
2687 return gen_rtx (code, GET_MODE (x), new);
2691 /* Similar to above processing, but preserve SUBREG_WORD.
2692 Convert (subreg (mem)) to (mem) if not paradoxical.
2693 Also, if we have a non-paradoxical (subreg (pseudo)) and the
2694 pseudo didn't get a hard reg, we must replace this with the
2695 eliminated version of the memory location because push_reloads
2696 may do the replacement in certain circumstances. */
2697 if (GET_CODE (SUBREG_REG (x)) == REG
2698 && (GET_MODE_SIZE (GET_MODE (x))
2699 <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
2700 && reg_equiv_memory_loc != 0
2701 && reg_equiv_memory_loc[REGNO (SUBREG_REG (x))] != 0)
2703 new = eliminate_regs (reg_equiv_memory_loc[REGNO (SUBREG_REG (x))],
2704 mem_mode, NULL_RTX);
2706 /* If we didn't change anything, we must retain the pseudo. */
2707 if (new == reg_equiv_memory_loc[REGNO (SUBREG_REG (x))])
2710 /* Otherwise, ensure NEW isn't shared in case we have to reload
2712 new = copy_rtx (new);
2715 new = eliminate_regs (SUBREG_REG (x), mem_mode, NULL_RTX);
2717 if (new != XEXP (x, 0))
2719 if (GET_CODE (new) == MEM
2720 && (GET_MODE_SIZE (GET_MODE (x))
2721 <= GET_MODE_SIZE (GET_MODE (new))))
2723 int offset = SUBREG_WORD (x) * UNITS_PER_WORD;
2724 enum machine_mode mode = GET_MODE (x);
2726 #if BYTES_BIG_ENDIAN
2727 offset += (MIN (UNITS_PER_WORD,
2728 GET_MODE_SIZE (GET_MODE (new)))
2729 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode)));
2732 PUT_MODE (new, mode);
2733 XEXP (new, 0) = plus_constant (XEXP (new, 0), offset);
2737 return gen_rtx (SUBREG, GET_MODE (x), new, SUBREG_WORD (x));
2743 /* If clobbering a register that is the replacement register for an
2744 elimination we still think can be performed, note that it cannot
2745 be performed. Otherwise, we need not be concerned about it. */
2746 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
2747 if (ep->to_rtx == XEXP (x, 0))
2748 ep->can_eliminate = 0;
2755 /* Properly handle sharing input and constraint vectors. */
2756 if (ASM_OPERANDS_INPUT_VEC (x) != old_asm_operands_vec)
2758 /* When we come to a new vector not seen before,
2759 scan all its elements; keep the old vector if none
2760 of them changes; otherwise, make a copy. */
2761 old_asm_operands_vec = ASM_OPERANDS_INPUT_VEC (x);
2762 temp_vec = (rtx *) alloca (XVECLEN (x, 3) * sizeof (rtx));
2763 for (i = 0; i < ASM_OPERANDS_INPUT_LENGTH (x); i++)
2764 temp_vec[i] = eliminate_regs (ASM_OPERANDS_INPUT (x, i),
2765 mem_mode, NULL_RTX);
2767 for (i = 0; i < ASM_OPERANDS_INPUT_LENGTH (x); i++)
2768 if (temp_vec[i] != ASM_OPERANDS_INPUT (x, i))
2771 if (i == ASM_OPERANDS_INPUT_LENGTH (x))
2772 new_asm_operands_vec = old_asm_operands_vec;
2774 new_asm_operands_vec
2775 = gen_rtvec_v (ASM_OPERANDS_INPUT_LENGTH (x), temp_vec);
2778 /* If we had to copy the vector, copy the entire ASM_OPERANDS. */
2779 if (new_asm_operands_vec == old_asm_operands_vec)
2782 new = gen_rtx (ASM_OPERANDS, VOIDmode, ASM_OPERANDS_TEMPLATE (x),
2783 ASM_OPERANDS_OUTPUT_CONSTRAINT (x),
2784 ASM_OPERANDS_OUTPUT_IDX (x), new_asm_operands_vec,
2785 ASM_OPERANDS_INPUT_CONSTRAINT_VEC (x),
2786 ASM_OPERANDS_SOURCE_FILE (x),
2787 ASM_OPERANDS_SOURCE_LINE (x));
2788 new->volatil = x->volatil;
2793 /* Check for setting a register that we know about. */
2794 if (GET_CODE (SET_DEST (x)) == REG)
2796 /* See if this is setting the replacement register for an
2799 If DEST is the frame pointer, we do nothing because we assume that
2800 all assignments to the frame pointer are for non-local gotos and
2801 are being done at a time when they are valid and do not disturb
2802 anything else. Some machines want to eliminate a fake argument
2803 pointer with either the frame or stack pointer. Assignments to
2804 the frame pointer must not prevent this elimination. */
2806 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS];
2808 if (ep->to_rtx == SET_DEST (x)
2809 && SET_DEST (x) != frame_pointer_rtx)
2811 /* If it is being incremented, adjust the offset. Otherwise,
2812 this elimination can't be done. */
2813 rtx src = SET_SRC (x);
2815 if (GET_CODE (src) == PLUS
2816 && XEXP (src, 0) == SET_DEST (x)
2817 && GET_CODE (XEXP (src, 1)) == CONST_INT)
2818 ep->offset -= INTVAL (XEXP (src, 1));
2820 ep->can_eliminate = 0;
2823 /* Now check to see we are assigning to a register that can be
2824 eliminated. If so, it must be as part of a PARALLEL, since we
2825 will not have been called if this is a single SET. So indicate
2826 that we can no longer eliminate this reg. */
2827 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS];
2829 if (ep->from_rtx == SET_DEST (x) && ep->can_eliminate)
2830 ep->can_eliminate = 0;
2833 /* Now avoid the loop below in this common case. */
2835 rtx new0 = eliminate_regs (SET_DEST (x), 0, NULL_RTX);
2836 rtx new1 = eliminate_regs (SET_SRC (x), 0, NULL_RTX);
2838 /* If SET_DEST changed from a REG to a MEM and INSN is non-zero,
2839 write a CLOBBER insn. */
2840 if (GET_CODE (SET_DEST (x)) == REG && GET_CODE (new0) == MEM
2842 emit_insn_after (gen_rtx (CLOBBER, VOIDmode, SET_DEST (x)), insn);
2844 if (new0 != SET_DEST (x) || new1 != SET_SRC (x))
2845 return gen_rtx (SET, VOIDmode, new0, new1);
2851 /* Our only special processing is to pass the mode of the MEM to our
2852 recursive call and copy the flags. While we are here, handle this
2853 case more efficiently. */
2854 new = eliminate_regs (XEXP (x, 0), GET_MODE (x), NULL_RTX);
2855 if (new != XEXP (x, 0))
2857 new = gen_rtx (MEM, GET_MODE (x), new);
2858 new->volatil = x->volatil;
2859 new->unchanging = x->unchanging;
2860 new->in_struct = x->in_struct;
2867 /* Process each of our operands recursively. If any have changed, make a
2869 fmt = GET_RTX_FORMAT (code);
2870 for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++)
2874 new = eliminate_regs (XEXP (x, i), mem_mode, NULL_RTX);
2875 if (new != XEXP (x, i) && ! copied)
2877 rtx new_x = rtx_alloc (code);
2878 bcopy (x, new_x, (sizeof (*new_x) - sizeof (new_x->fld)
2879 + (sizeof (new_x->fld[0])
2880 * GET_RTX_LENGTH (code))));
2886 else if (*fmt == 'E')
2889 for (j = 0; j < XVECLEN (x, i); j++)
2891 new = eliminate_regs (XVECEXP (x, i, j), mem_mode, insn);
2892 if (new != XVECEXP (x, i, j) && ! copied_vec)
2894 rtvec new_v = gen_rtvec_v (XVECLEN (x, i),
2895 &XVECEXP (x, i, 0));
2898 rtx new_x = rtx_alloc (code);
2899 bcopy (x, new_x, (sizeof (*new_x) - sizeof (new_x->fld)
2900 + (sizeof (new_x->fld[0])
2901 * GET_RTX_LENGTH (code))));
2905 XVEC (x, i) = new_v;
2908 XVECEXP (x, i, j) = new;
2916 /* Scan INSN and eliminate all eliminable registers in it.
2918 If REPLACE is nonzero, do the replacement destructively. Also
2919 delete the insn as dead it if it is setting an eliminable register.
2921 If REPLACE is zero, do all our allocations in reload_obstack.
2923 If no eliminations were done and this insn doesn't require any elimination
2924 processing (these are not identical conditions: it might be updating sp,
2925 but not referencing fp; this needs to be seen during reload_as_needed so
2926 that the offset between fp and sp can be taken into consideration), zero
2927 is returned. Otherwise, 1 is returned. */
2930 eliminate_regs_in_insn (insn, replace)
2934 rtx old_body = PATTERN (insn);
2937 struct elim_table *ep;
2940 push_obstacks (&reload_obstack, &reload_obstack);
2942 if (GET_CODE (old_body) == SET && GET_CODE (SET_DEST (old_body)) == REG
2943 && REGNO (SET_DEST (old_body)) < FIRST_PSEUDO_REGISTER)
2945 /* Check for setting an eliminable register. */
2946 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
2947 if (ep->from_rtx == SET_DEST (old_body) && ep->can_eliminate)
2949 /* In this case this insn isn't serving a useful purpose. We
2950 will delete it in reload_as_needed once we know that this
2951 elimination is, in fact, being done.
2953 If REPLACE isn't set, we can't delete this insn, but neededn't
2954 process it since it won't be used unless something changes. */
2956 delete_dead_insn (insn);
2961 /* Check for (set (reg) (plus (reg from) (offset))) where the offset
2962 in the insn is the negative of the offset in FROM. Substitute
2963 (set (reg) (reg to)) for the insn and change its code.
2965 We have to do this here, rather than in eliminate_regs, do that we can
2966 change the insn code. */
2968 if (GET_CODE (SET_SRC (old_body)) == PLUS
2969 && GET_CODE (XEXP (SET_SRC (old_body), 0)) == REG
2970 && GET_CODE (XEXP (SET_SRC (old_body), 1)) == CONST_INT)
2971 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS];
2973 if (ep->from_rtx == XEXP (SET_SRC (old_body), 0)
2974 && ep->can_eliminate
2975 && ep->offset == - INTVAL (XEXP (SET_SRC (old_body), 1)))
2977 PATTERN (insn) = gen_rtx (SET, VOIDmode,
2978 SET_DEST (old_body), ep->to_rtx);
2979 INSN_CODE (insn) = -1;
2985 old_asm_operands_vec = 0;
2987 /* Replace the body of this insn with a substituted form. If we changed
2988 something, return non-zero. If this is the final call for this
2989 insn (REPLACE is non-zero), do the elimination in REG_NOTES as well.
2991 If we are replacing a body that was a (set X (plus Y Z)), try to
2992 re-recognize the insn. We do this in case we had a simple addition
2993 but now can do this as a load-address. This saves an insn in this
2996 new_body = eliminate_regs (old_body, 0, replace ? insn : NULL_RTX);
2997 if (new_body != old_body)
2999 /* If we had a move insn but now we don't, rerecognize it. */
3000 if ((GET_CODE (old_body) == SET && GET_CODE (SET_SRC (old_body)) == REG
3001 && (GET_CODE (new_body) != SET
3002 || GET_CODE (SET_SRC (new_body)) != REG))
3003 /* If this was an add insn before, rerecognize. */
3005 (GET_CODE (old_body) == SET
3006 && GET_CODE (SET_SRC (old_body)) == PLUS))
3008 if (! validate_change (insn, &PATTERN (insn), new_body, 0))
3009 /* If recognition fails, store the new body anyway.
3010 It's normal to have recognition failures here
3011 due to bizarre memory addresses; reloading will fix them. */
3012 PATTERN (insn) = new_body;
3015 PATTERN (insn) = new_body;
3017 if (replace && REG_NOTES (insn))
3018 REG_NOTES (insn) = eliminate_regs (REG_NOTES (insn), 0, NULL_RTX);
3022 /* Loop through all elimination pairs. See if any have changed and
3023 recalculate the number not at initial offset.
3025 Compute the maximum offset (minimum offset if the stack does not
3026 grow downward) for each elimination pair.
3028 We also detect a cases where register elimination cannot be done,
3029 namely, if a register would be both changed and referenced outside a MEM
3030 in the resulting insn since such an insn is often undefined and, even if
3031 not, we cannot know what meaning will be given to it. Note that it is
3032 valid to have a register used in an address in an insn that changes it
3033 (presumably with a pre- or post-increment or decrement).
3035 If anything changes, return nonzero. */
3037 num_not_at_initial_offset = 0;
3038 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
3040 if (ep->previous_offset != ep->offset && ep->ref_outside_mem)
3041 ep->can_eliminate = 0;
3043 ep->ref_outside_mem = 0;
3045 if (ep->previous_offset != ep->offset)
3048 ep->previous_offset = ep->offset;
3049 if (ep->can_eliminate && ep->offset != ep->initial_offset)
3050 num_not_at_initial_offset++;
3052 #ifdef STACK_GROWS_DOWNWARD
3053 ep->max_offset = MAX (ep->max_offset, ep->offset);
3055 ep->max_offset = MIN (ep->max_offset, ep->offset);
3066 /* Given X, a SET or CLOBBER of DEST, if DEST is the target of a register
3067 replacement we currently believe is valid, mark it as not eliminable if X
3068 modifies DEST in any way other than by adding a constant integer to it.
3070 If DEST is the frame pointer, we do nothing because we assume that
3071 all assignments to the frame pointer are nonlocal gotos and are being done
3072 at a time when they are valid and do not disturb anything else.
3073 Some machines want to eliminate a fake argument pointer with either the
3074 frame or stack pointer. Assignments to the frame pointer must not prevent
3077 Called via note_stores from reload before starting its passes to scan
3078 the insns of the function. */
3081 mark_not_eliminable (dest, x)
3087 /* A SUBREG of a hard register here is just changing its mode. We should
3088 not see a SUBREG of an eliminable hard register, but check just in
3090 if (GET_CODE (dest) == SUBREG)
3091 dest = SUBREG_REG (dest);
3093 if (dest == frame_pointer_rtx)
3096 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
3097 if (reg_eliminate[i].can_eliminate && dest == reg_eliminate[i].to_rtx
3098 && (GET_CODE (x) != SET
3099 || GET_CODE (SET_SRC (x)) != PLUS
3100 || XEXP (SET_SRC (x), 0) != dest
3101 || GET_CODE (XEXP (SET_SRC (x), 1)) != CONST_INT))
3103 reg_eliminate[i].can_eliminate_previous
3104 = reg_eliminate[i].can_eliminate = 0;
3109 /* Kick all pseudos out of hard register REGNO.
3110 If GLOBAL is nonzero, try to find someplace else to put them.
3111 If DUMPFILE is nonzero, log actions taken on that file.
3113 If CANT_ELIMINATE is nonzero, it means that we are doing this spill
3114 because we found we can't eliminate some register. In the case, no pseudos
3115 are allowed to be in the register, even if they are only in a block that
3116 doesn't require spill registers, unlike the case when we are spilling this
3117 hard reg to produce another spill register.
3119 Return nonzero if any pseudos needed to be kicked out. */
3122 spill_hard_reg (regno, global, dumpfile, cant_eliminate)
3128 int something_changed = 0;
3131 SET_HARD_REG_BIT (forbidden_regs, regno);
3133 /* Spill every pseudo reg that was allocated to this reg
3134 or to something that overlaps this reg. */
3136 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
3137 if (reg_renumber[i] >= 0
3138 && reg_renumber[i] <= regno
3140 + HARD_REGNO_NREGS (reg_renumber[i],
3141 PSEUDO_REGNO_MODE (i))
3144 enum reg_class class = REGNO_REG_CLASS (regno);
3146 /* If this register belongs solely to a basic block which needed no
3147 spilling of any class that this register is contained in,
3148 leave it be, unless we are spilling this register because
3149 it was a hard register that can't be eliminated. */
3151 if (! cant_eliminate
3152 && basic_block_needs[0]
3153 && reg_basic_block[i] >= 0
3154 && basic_block_needs[(int) class][reg_basic_block[i]] == 0)
3158 for (p = reg_class_superclasses[(int) class];
3159 *p != LIM_REG_CLASSES; p++)
3160 if (basic_block_needs[(int) *p][reg_basic_block[i]] > 0)
3163 if (*p == LIM_REG_CLASSES)
3167 /* Mark it as no longer having a hard register home. */
3168 reg_renumber[i] = -1;
3169 /* We will need to scan everything again. */
3170 something_changed = 1;
3172 retry_global_alloc (i, forbidden_regs);
3174 alter_reg (i, regno);
3177 if (reg_renumber[i] == -1)
3178 fprintf (dumpfile, " Register %d now on stack.\n\n", i);
3180 fprintf (dumpfile, " Register %d now in %d.\n\n",
3181 i, reg_renumber[i]);
3185 return something_changed;
3188 /* Find all paradoxical subregs within X and update reg_max_ref_width. */
3191 scan_paradoxical_subregs (x)
3196 register enum rtx_code code = GET_CODE (x);
3213 if (GET_CODE (SUBREG_REG (x)) == REG
3214 && GET_MODE_SIZE (GET_MODE (x)) > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
3215 reg_max_ref_width[REGNO (SUBREG_REG (x))]
3216 = GET_MODE_SIZE (GET_MODE (x));
3220 fmt = GET_RTX_FORMAT (code);
3221 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3224 scan_paradoxical_subregs (XEXP (x, i));
3225 else if (fmt[i] == 'E')
3228 for (j = XVECLEN (x, i) - 1; j >=0; j--)
3229 scan_paradoxical_subregs (XVECEXP (x, i, j));
3234 struct hard_reg_n_uses { int regno; int uses; };
3237 hard_reg_use_compare (p1, p2)
3238 struct hard_reg_n_uses *p1, *p2;
3240 int tem = p1->uses - p2->uses;
3241 if (tem != 0) return tem;
3242 /* If regs are equally good, sort by regno,
3243 so that the results of qsort leave nothing to chance. */
3244 return p1->regno - p2->regno;
3247 /* Choose the order to consider regs for use as reload registers
3248 based on how much trouble would be caused by spilling one.
3249 Store them in order of decreasing preference in potential_reload_regs. */
3252 order_regs_for_reload ()
3258 struct hard_reg_n_uses hard_reg_n_uses[FIRST_PSEUDO_REGISTER];
3260 CLEAR_HARD_REG_SET (bad_spill_regs);
3262 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3263 potential_reload_regs[i] = -1;
3265 /* Count number of uses of each hard reg by pseudo regs allocated to it
3266 and then order them by decreasing use. */
3268 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3270 hard_reg_n_uses[i].uses = 0;
3271 hard_reg_n_uses[i].regno = i;
3274 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
3276 int regno = reg_renumber[i];
3279 int lim = regno + HARD_REGNO_NREGS (regno, PSEUDO_REGNO_MODE (i));
3281 hard_reg_n_uses[regno++].uses += reg_n_refs[i];
3283 large += reg_n_refs[i];
3286 /* Now fixed registers (which cannot safely be used for reloading)
3287 get a very high use count so they will be considered least desirable.
3288 Registers used explicitly in the rtl code are almost as bad. */
3290 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3294 hard_reg_n_uses[i].uses += 2 * large + 2;
3295 SET_HARD_REG_BIT (bad_spill_regs, i);
3297 else if (regs_explicitly_used[i])
3299 hard_reg_n_uses[i].uses += large + 1;
3300 /* ??? We are doing this here because of the potential that
3301 bad code may be generated if a register explicitly used in
3302 an insn was used as a spill register for that insn. But
3303 not using these are spill registers may lose on some machine.
3304 We'll have to see how this works out. */
3305 SET_HARD_REG_BIT (bad_spill_regs, i);
3308 hard_reg_n_uses[FRAME_POINTER_REGNUM].uses += 2 * large + 2;
3309 SET_HARD_REG_BIT (bad_spill_regs, FRAME_POINTER_REGNUM);
3311 #ifdef ELIMINABLE_REGS
3312 /* If registers other than the frame pointer are eliminable, mark them as
3314 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
3316 hard_reg_n_uses[reg_eliminate[i].from].uses += 2 * large + 2;
3317 SET_HARD_REG_BIT (bad_spill_regs, reg_eliminate[i].from);
3321 /* Prefer registers not so far used, for use in temporary loading.
3322 Among them, if REG_ALLOC_ORDER is defined, use that order.
3323 Otherwise, prefer registers not preserved by calls. */
3325 #ifdef REG_ALLOC_ORDER
3326 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3328 int regno = reg_alloc_order[i];
3330 if (hard_reg_n_uses[regno].uses == 0)
3331 potential_reload_regs[o++] = regno;
3334 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3336 if (hard_reg_n_uses[i].uses == 0 && call_used_regs[i])
3337 potential_reload_regs[o++] = i;
3339 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3341 if (hard_reg_n_uses[i].uses == 0 && ! call_used_regs[i])
3342 potential_reload_regs[o++] = i;
3346 qsort (hard_reg_n_uses, FIRST_PSEUDO_REGISTER,
3347 sizeof hard_reg_n_uses[0], hard_reg_use_compare);
3349 /* Now add the regs that are already used,
3350 preferring those used less often. The fixed and otherwise forbidden
3351 registers will be at the end of this list. */
3353 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3354 if (hard_reg_n_uses[i].uses != 0)
3355 potential_reload_regs[o++] = hard_reg_n_uses[i].regno;
3358 /* Reload pseudo-registers into hard regs around each insn as needed.
3359 Additional register load insns are output before the insn that needs it
3360 and perhaps store insns after insns that modify the reloaded pseudo reg.
3362 reg_last_reload_reg and reg_reloaded_contents keep track of
3363 which pseudo-registers are already available in reload registers.
3364 We update these for the reloads that we perform,
3365 as the insns are scanned. */
3368 reload_as_needed (first, live_known)
3378 bzero (spill_reg_rtx, sizeof spill_reg_rtx);
3379 reg_last_reload_reg = (rtx *) alloca (max_regno * sizeof (rtx));
3380 bzero (reg_last_reload_reg, max_regno * sizeof (rtx));
3381 reg_has_output_reload = (char *) alloca (max_regno);
3382 for (i = 0; i < n_spills; i++)
3384 reg_reloaded_contents[i] = -1;
3385 reg_reloaded_insn[i] = 0;
3388 /* Reset all offsets on eliminable registers to their initial values. */
3389 #ifdef ELIMINABLE_REGS
3390 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
3392 INITIAL_ELIMINATION_OFFSET (reg_eliminate[i].from, reg_eliminate[i].to,
3393 reg_eliminate[i].initial_offset);
3394 reg_eliminate[i].previous_offset
3395 = reg_eliminate[i].offset = reg_eliminate[i].initial_offset;
3398 INITIAL_FRAME_POINTER_OFFSET (reg_eliminate[0].initial_offset);
3399 reg_eliminate[0].previous_offset
3400 = reg_eliminate[0].offset = reg_eliminate[0].initial_offset;
3403 num_not_at_initial_offset = 0;
3405 for (insn = first; insn;)
3407 register rtx next = NEXT_INSN (insn);
3409 /* Notice when we move to a new basic block. */
3410 if (live_known && this_block + 1 < n_basic_blocks
3411 && insn == basic_block_head[this_block+1])
3414 /* If we pass a label, copy the offsets from the label information
3415 into the current offsets of each elimination. */
3416 if (GET_CODE (insn) == CODE_LABEL)
3418 num_not_at_initial_offset = 0;
3419 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
3421 reg_eliminate[i].offset = reg_eliminate[i].previous_offset
3422 = offsets_at[CODE_LABEL_NUMBER (insn)][i];
3423 if (reg_eliminate[i].can_eliminate
3424 && (reg_eliminate[i].offset
3425 != reg_eliminate[i].initial_offset))
3426 num_not_at_initial_offset++;
3430 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
3432 rtx avoid_return_reg = 0;
3434 #ifdef SMALL_REGISTER_CLASSES
3435 /* Set avoid_return_reg if this is an insn
3436 that might use the value of a function call. */
3437 if (GET_CODE (insn) == CALL_INSN)
3439 if (GET_CODE (PATTERN (insn)) == SET)
3440 after_call = SET_DEST (PATTERN (insn));
3441 else if (GET_CODE (PATTERN (insn)) == PARALLEL
3442 && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET)
3443 after_call = SET_DEST (XVECEXP (PATTERN (insn), 0, 0));
3447 else if (after_call != 0
3448 && !(GET_CODE (PATTERN (insn)) == SET
3449 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx))
3451 if (reg_mentioned_p (after_call, PATTERN (insn)))
3452 avoid_return_reg = after_call;
3455 #endif /* SMALL_REGISTER_CLASSES */
3457 /* If this is a USE and CLOBBER of a MEM, ensure that any
3458 references to eliminable registers have been removed. */
3460 if ((GET_CODE (PATTERN (insn)) == USE
3461 || GET_CODE (PATTERN (insn)) == CLOBBER)
3462 && GET_CODE (XEXP (PATTERN (insn), 0)) == MEM)
3463 XEXP (XEXP (PATTERN (insn), 0), 0)
3464 = eliminate_regs (XEXP (XEXP (PATTERN (insn), 0), 0),
3465 GET_MODE (XEXP (PATTERN (insn), 0)), NULL_RTX);
3467 /* If we need to do register elimination processing, do so.
3468 This might delete the insn, in which case we are done. */
3469 if (num_eliminable && GET_MODE (insn) == QImode)
3471 eliminate_regs_in_insn (insn, 1);
3472 if (GET_CODE (insn) == NOTE)
3479 if (GET_MODE (insn) == VOIDmode)
3481 /* First find the pseudo regs that must be reloaded for this insn.
3482 This info is returned in the tables reload_... (see reload.h).
3483 Also modify the body of INSN by substituting RELOAD
3484 rtx's for those pseudo regs. */
3487 bzero (reg_has_output_reload, max_regno);
3488 CLEAR_HARD_REG_SET (reg_is_output_reload);
3490 find_reloads (insn, 1, spill_indirect_levels, live_known,
3496 rtx prev = PREV_INSN (insn), next = NEXT_INSN (insn);
3500 /* If this block has not had spilling done for a
3501 particular class, deactivate any optional reloads
3502 of that class lest they try to use a spill-reg which isn't
3503 available here. If we have any non-optionals that need a
3504 spill reg, abort. */
3506 for (class = 0; class < N_REG_CLASSES; class++)
3507 if (basic_block_needs[class] != 0
3508 && basic_block_needs[class][this_block] == 0)
3509 for (i = 0; i < n_reloads; i++)
3510 if (class == (int) reload_reg_class[i])
3512 if (reload_optional[i])
3514 reload_in[i] = reload_out[i] = 0;
3515 reload_secondary_p[i] = 0;
3517 else if (reload_reg_rtx[i] == 0
3518 && (reload_in[i] != 0 || reload_out[i] != 0
3519 || reload_secondary_p[i] != 0))
3523 /* Now compute which reload regs to reload them into. Perhaps
3524 reusing reload regs from previous insns, or else output
3525 load insns to reload them. Maybe output store insns too.
3526 Record the choices of reload reg in reload_reg_rtx. */
3527 choose_reload_regs (insn, avoid_return_reg);
3529 /* Generate the insns to reload operands into or out of
3530 their reload regs. */
3531 emit_reload_insns (insn);
3533 /* Substitute the chosen reload regs from reload_reg_rtx
3534 into the insn's body (or perhaps into the bodies of other
3535 load and store insn that we just made for reloading
3536 and that we moved the structure into). */
3539 /* If this was an ASM, make sure that all the reload insns
3540 we have generated are valid. If not, give an error
3543 if (asm_noperands (PATTERN (insn)) >= 0)
3544 for (p = NEXT_INSN (prev); p != next; p = NEXT_INSN (p))
3545 if (p != insn && GET_RTX_CLASS (GET_CODE (p)) == 'i'
3546 && (recog_memoized (p) < 0
3547 || (insn_extract (p),
3548 ! constrain_operands (INSN_CODE (p), 1))))
3550 error_for_asm (insn,
3551 "`asm' operand requires impossible reload");
3553 NOTE_SOURCE_FILE (p) = 0;
3554 NOTE_LINE_NUMBER (p) = NOTE_INSN_DELETED;
3557 /* Any previously reloaded spilled pseudo reg, stored in this insn,
3558 is no longer validly lying around to save a future reload.
3559 Note that this does not detect pseudos that were reloaded
3560 for this insn in order to be stored in
3561 (obeying register constraints). That is correct; such reload
3562 registers ARE still valid. */
3563 note_stores (PATTERN (insn), forget_old_reloads_1);
3565 /* There may have been CLOBBER insns placed after INSN. So scan
3566 between INSN and NEXT and use them to forget old reloads. */
3567 for (x = NEXT_INSN (insn); x != next; x = NEXT_INSN (x))
3568 if (GET_CODE (x) == INSN && GET_CODE (PATTERN (x)) == CLOBBER)
3569 note_stores (PATTERN (x), forget_old_reloads_1);
3572 /* Likewise for regs altered by auto-increment in this insn.
3573 But note that the reg-notes are not changed by reloading:
3574 they still contain the pseudo-regs, not the spill regs. */
3575 for (x = REG_NOTES (insn); x; x = XEXP (x, 1))
3576 if (REG_NOTE_KIND (x) == REG_INC)
3578 /* See if this pseudo reg was reloaded in this insn.
3579 If so, its last-reload info is still valid
3580 because it is based on this insn's reload. */
3581 for (i = 0; i < n_reloads; i++)
3582 if (reload_out[i] == XEXP (x, 0))
3586 forget_old_reloads_1 (XEXP (x, 0));
3590 /* A reload reg's contents are unknown after a label. */
3591 if (GET_CODE (insn) == CODE_LABEL)
3592 for (i = 0; i < n_spills; i++)
3594 reg_reloaded_contents[i] = -1;
3595 reg_reloaded_insn[i] = 0;
3598 /* Don't assume a reload reg is still good after a call insn
3599 if it is a call-used reg. */
3600 if (GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == CALL_INSN)
3601 for (i = 0; i < n_spills; i++)
3602 if (call_used_regs[spill_regs[i]])
3604 reg_reloaded_contents[i] = -1;
3605 reg_reloaded_insn[i] = 0;
3608 /* In case registers overlap, allow certain insns to invalidate
3609 particular hard registers. */
3611 #ifdef INSN_CLOBBERS_REGNO_P
3612 for (i = 0 ; i < n_spills ; i++)
3613 if (INSN_CLOBBERS_REGNO_P (insn, spill_regs[i]))
3615 reg_reloaded_contents[i] = -1;
3616 reg_reloaded_insn[i] = 0;
3628 /* Discard all record of any value reloaded from X,
3629 or reloaded in X from someplace else;
3630 unless X is an output reload reg of the current insn.
3632 X may be a hard reg (the reload reg)
3633 or it may be a pseudo reg that was reloaded from. */
3636 forget_old_reloads_1 (x)
3643 /* note_stores does give us subregs of hard regs. */
3644 while (GET_CODE (x) == SUBREG)
3646 offset += SUBREG_WORD (x);
3650 if (GET_CODE (x) != REG)
3653 regno = REGNO (x) + offset;
3655 if (regno >= FIRST_PSEUDO_REGISTER)
3660 nr = HARD_REGNO_NREGS (regno, GET_MODE (x));
3661 /* Storing into a spilled-reg invalidates its contents.
3662 This can happen if a block-local pseudo is allocated to that reg
3663 and it wasn't spilled because this block's total need is 0.
3664 Then some insn might have an optional reload and use this reg. */
3665 for (i = 0; i < nr; i++)
3666 if (spill_reg_order[regno + i] >= 0
3667 /* But don't do this if the reg actually serves as an output
3668 reload reg in the current instruction. */
3670 || ! TEST_HARD_REG_BIT (reg_is_output_reload, regno + i)))
3672 reg_reloaded_contents[spill_reg_order[regno + i]] = -1;
3673 reg_reloaded_insn[spill_reg_order[regno + i]] = 0;
3677 /* Since value of X has changed,
3678 forget any value previously copied from it. */
3681 /* But don't forget a copy if this is the output reload
3682 that establishes the copy's validity. */
3683 if (n_reloads == 0 || reg_has_output_reload[regno + nr] == 0)
3684 reg_last_reload_reg[regno + nr] = 0;
3687 /* For each reload, the mode of the reload register. */
3688 static enum machine_mode reload_mode[MAX_RELOADS];
3690 /* For each reload, the largest number of registers it will require. */
3691 static int reload_nregs[MAX_RELOADS];
3693 /* Comparison function for qsort to decide which of two reloads
3694 should be handled first. *P1 and *P2 are the reload numbers. */
3697 reload_reg_class_lower (p1, p2)
3700 register int r1 = *p1, r2 = *p2;
3703 /* Consider required reloads before optional ones. */
3704 t = reload_optional[r1] - reload_optional[r2];
3708 /* Count all solitary classes before non-solitary ones. */
3709 t = ((reg_class_size[(int) reload_reg_class[r2]] == 1)
3710 - (reg_class_size[(int) reload_reg_class[r1]] == 1));
3714 /* Aside from solitaires, consider all multi-reg groups first. */
3715 t = reload_nregs[r2] - reload_nregs[r1];
3719 /* Consider reloads in order of increasing reg-class number. */
3720 t = (int) reload_reg_class[r1] - (int) reload_reg_class[r2];
3724 /* If reloads are equally urgent, sort by reload number,
3725 so that the results of qsort leave nothing to chance. */
3729 /* The following HARD_REG_SETs indicate when each hard register is
3730 used for a reload of various parts of the current insn. */
3732 /* If reg is in use as a reload reg for a RELOAD_OTHER reload. */
3733 static HARD_REG_SET reload_reg_used;
3734 /* If reg is in use for a RELOAD_FOR_INPUT_RELOAD_ADDRESS reload. */
3735 static HARD_REG_SET reload_reg_used_in_input_addr;
3736 /* If reg is in use for a RELOAD_FOR_OUTPUT_RELOAD_ADDRESS reload. */
3737 static HARD_REG_SET reload_reg_used_in_output_addr;
3738 /* If reg is in use for a RELOAD_FOR_OPERAND_ADDRESS reload. */
3739 static HARD_REG_SET reload_reg_used_in_op_addr;
3740 /* If reg is in use for a RELOAD_FOR_INPUT reload. */
3741 static HARD_REG_SET reload_reg_used_in_input;
3742 /* If reg is in use for a RELOAD_FOR_OUTPUT reload. */
3743 static HARD_REG_SET reload_reg_used_in_output;
3745 /* If reg is in use as a reload reg for any sort of reload. */
3746 static HARD_REG_SET reload_reg_used_at_all;
3748 /* Mark reg REGNO as in use for a reload of the sort spec'd by WHEN_NEEDED.
3749 MODE is used to indicate how many consecutive regs are actually used. */
3752 mark_reload_reg_in_use (regno, when_needed, mode)
3754 enum reload_when_needed when_needed;
3755 enum machine_mode mode;
3757 int nregs = HARD_REGNO_NREGS (regno, mode);
3760 for (i = regno; i < nregs + regno; i++)
3762 switch (when_needed)
3765 SET_HARD_REG_BIT (reload_reg_used, i);
3768 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
3769 SET_HARD_REG_BIT (reload_reg_used_in_input_addr, i);
3772 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
3773 SET_HARD_REG_BIT (reload_reg_used_in_output_addr, i);
3776 case RELOAD_FOR_OPERAND_ADDRESS:
3777 SET_HARD_REG_BIT (reload_reg_used_in_op_addr, i);
3780 case RELOAD_FOR_INPUT:
3781 SET_HARD_REG_BIT (reload_reg_used_in_input, i);
3784 case RELOAD_FOR_OUTPUT:
3785 SET_HARD_REG_BIT (reload_reg_used_in_output, i);
3789 SET_HARD_REG_BIT (reload_reg_used_at_all, i);
3793 /* 1 if reg REGNO is free as a reload reg for a reload of the sort
3794 specified by WHEN_NEEDED. */
3797 reload_reg_free_p (regno, when_needed)
3799 enum reload_when_needed when_needed;
3801 /* In use for a RELOAD_OTHER means it's not available for anything. */
3802 if (TEST_HARD_REG_BIT (reload_reg_used, regno))
3804 switch (when_needed)
3807 /* In use for anything means not available for a RELOAD_OTHER. */
3808 return ! TEST_HARD_REG_BIT (reload_reg_used_at_all, regno);
3810 /* The other kinds of use can sometimes share a register. */
3811 case RELOAD_FOR_INPUT:
3812 return (! TEST_HARD_REG_BIT (reload_reg_used_in_input, regno)
3813 && ! TEST_HARD_REG_BIT (reload_reg_used_in_op_addr, regno)
3814 && ! TEST_HARD_REG_BIT (reload_reg_used_in_input_addr, regno));
3815 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
3816 return (! TEST_HARD_REG_BIT (reload_reg_used_in_input_addr, regno)
3817 && ! TEST_HARD_REG_BIT (reload_reg_used_in_input, regno));
3818 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
3819 return (! TEST_HARD_REG_BIT (reload_reg_used_in_output_addr, regno)
3820 && ! TEST_HARD_REG_BIT (reload_reg_used_in_output, regno));
3821 case RELOAD_FOR_OPERAND_ADDRESS:
3822 return (! TEST_HARD_REG_BIT (reload_reg_used_in_op_addr, regno)
3823 && ! TEST_HARD_REG_BIT (reload_reg_used_in_input, regno)
3824 && ! TEST_HARD_REG_BIT (reload_reg_used_in_output, regno));
3825 case RELOAD_FOR_OUTPUT:
3826 return (! TEST_HARD_REG_BIT (reload_reg_used_in_op_addr, regno)
3827 && ! TEST_HARD_REG_BIT (reload_reg_used_in_output_addr, regno)
3828 && ! TEST_HARD_REG_BIT (reload_reg_used_in_output, regno));
3833 /* Return 1 if the value in reload reg REGNO, as used by a reload
3834 needed for the part of the insn specified by WHEN_NEEDED,
3835 is not in use for a reload in any prior part of the insn.
3837 We can assume that the reload reg was already tested for availability
3838 at the time it is needed, and we should not check this again,
3839 in case the reg has already been marked in use. */
3842 reload_reg_free_before_p (regno, when_needed)
3844 enum reload_when_needed when_needed;
3846 switch (when_needed)
3849 /* Since a RELOAD_OTHER reload claims the reg for the entire insn,
3850 its use starts from the beginning, so nothing can use it earlier. */
3853 /* If this use is for part of the insn,
3854 check the reg is not in use for any prior part. */
3855 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
3856 if (TEST_HARD_REG_BIT (reload_reg_used_in_op_addr, regno))
3858 case RELOAD_FOR_OUTPUT:
3859 if (TEST_HARD_REG_BIT (reload_reg_used_in_input, regno))
3861 case RELOAD_FOR_OPERAND_ADDRESS:
3862 if (TEST_HARD_REG_BIT (reload_reg_used_in_input_addr, regno))
3864 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
3865 case RELOAD_FOR_INPUT:
3871 /* Return 1 if the value in reload reg REGNO, as used by a reload
3872 needed for the part of the insn specified by WHEN_NEEDED,
3873 is still available in REGNO at the end of the insn.
3875 We can assume that the reload reg was already tested for availability
3876 at the time it is needed, and we should not check this again,
3877 in case the reg has already been marked in use. */
3880 reload_reg_reaches_end_p (regno, when_needed)
3882 enum reload_when_needed when_needed;
3884 switch (when_needed)
3887 /* Since a RELOAD_OTHER reload claims the reg for the entire insn,
3888 its value must reach the end. */
3891 /* If this use is for part of the insn,
3892 its value reaches if no subsequent part uses the same register. */
3893 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
3894 case RELOAD_FOR_INPUT:
3895 if (TEST_HARD_REG_BIT (reload_reg_used_in_op_addr, regno)
3896 || TEST_HARD_REG_BIT (reload_reg_used_in_output, regno))
3898 case RELOAD_FOR_OPERAND_ADDRESS:
3899 if (TEST_HARD_REG_BIT (reload_reg_used_in_output_addr, regno))
3901 case RELOAD_FOR_OUTPUT:
3902 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
3908 /* Vector of reload-numbers showing the order in which the reloads should
3910 short reload_order[MAX_RELOADS];
3912 /* Indexed by reload number, 1 if incoming value
3913 inherited from previous insns. */
3914 char reload_inherited[MAX_RELOADS];
3916 /* For an inherited reload, this is the insn the reload was inherited from,
3917 if we know it. Otherwise, this is 0. */
3918 rtx reload_inheritance_insn[MAX_RELOADS];
3920 /* If non-zero, this is a place to get the value of the reload,
3921 rather than using reload_in. */
3922 rtx reload_override_in[MAX_RELOADS];
3924 /* For each reload, the index in spill_regs of the spill register used,
3925 or -1 if we did not need one of the spill registers for this reload. */
3926 int reload_spill_index[MAX_RELOADS];
3928 /* Index of last register assigned as a spill register. We allocate in
3929 a round-robin fashio. */
3931 static last_spill_reg = 0;
3933 /* Find a spill register to use as a reload register for reload R.
3934 LAST_RELOAD is non-zero if this is the last reload for the insn being
3937 Set reload_reg_rtx[R] to the register allocated.
3939 If NOERROR is nonzero, we return 1 if successful,
3940 or 0 if we couldn't find a spill reg and we didn't change anything. */
3943 allocate_reload_reg (r, insn, last_reload, noerror)
3955 /* If we put this reload ahead, thinking it is a group,
3956 then insist on finding a group. Otherwise we can grab a
3957 reg that some other reload needs.
3958 (That can happen when we have a 68000 DATA_OR_FP_REG
3959 which is a group of data regs or one fp reg.)
3960 We need not be so restrictive if there are no more reloads
3963 ??? Really it would be nicer to have smarter handling
3964 for that kind of reg class, where a problem like this is normal.
3965 Perhaps those classes should be avoided for reloading
3966 by use of more alternatives. */
3968 int force_group = reload_nregs[r] > 1 && ! last_reload;
3970 /* If we want a single register and haven't yet found one,
3971 take any reg in the right class and not in use.
3972 If we want a consecutive group, here is where we look for it.
3974 We use two passes so we can first look for reload regs to
3975 reuse, which are already in use for other reloads in this insn,
3976 and only then use additional registers.
3977 I think that maximizing reuse is needed to make sure we don't
3978 run out of reload regs. Suppose we have three reloads, and
3979 reloads A and B can share regs. These need two regs.
3980 Suppose A and B are given different regs.
3981 That leaves none for C. */
3982 for (pass = 0; pass < 2; pass++)
3984 /* I is the index in spill_regs.
3985 We advance it round-robin between insns to use all spill regs
3986 equally, so that inherited reloads have a chance
3987 of leapfrogging each other. */
3989 for (count = 0, i = last_spill_reg; count < n_spills; count++)
3991 int class = (int) reload_reg_class[r];
3993 i = (i + 1) % n_spills;
3995 if (reload_reg_free_p (spill_regs[i], reload_when_needed[r])
3996 && TEST_HARD_REG_BIT (reg_class_contents[class], spill_regs[i])
3997 && HARD_REGNO_MODE_OK (spill_regs[i], reload_mode[r])
3998 /* Look first for regs to share, then for unshared. */
3999 && (pass || TEST_HARD_REG_BIT (reload_reg_used_at_all,
4002 int nr = HARD_REGNO_NREGS (spill_regs[i], reload_mode[r]);
4003 /* Avoid the problem where spilling a GENERAL_OR_FP_REG
4004 (on 68000) got us two FP regs. If NR is 1,
4005 we would reject both of them. */
4007 nr = CLASS_MAX_NREGS (reload_reg_class[r], reload_mode[r]);
4008 /* If we need only one reg, we have already won. */
4011 /* But reject a single reg if we demand a group. */
4016 /* Otherwise check that as many consecutive regs as we need
4018 Also, don't use for a group registers that are
4019 needed for nongroups. */
4020 if (! TEST_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]))
4023 regno = spill_regs[i] + nr - 1;
4024 if (!(TEST_HARD_REG_BIT (reg_class_contents[class], regno)
4025 && spill_reg_order[regno] >= 0
4026 && reload_reg_free_p (regno, reload_when_needed[r])
4027 && ! TEST_HARD_REG_BIT (counted_for_nongroups,
4037 /* If we found something on pass 1, omit pass 2. */
4038 if (count < n_spills)
4042 /* We should have found a spill register by now. */
4043 if (count == n_spills)
4052 /* Mark as in use for this insn the reload regs we use for this. */
4053 mark_reload_reg_in_use (spill_regs[i], reload_when_needed[r],
4056 new = spill_reg_rtx[i];
4058 if (new == 0 || GET_MODE (new) != reload_mode[r])
4059 spill_reg_rtx[i] = new = gen_rtx (REG, reload_mode[r], spill_regs[i]);
4061 reload_reg_rtx[r] = new;
4062 reload_spill_index[r] = i;
4063 regno = true_regnum (new);
4065 /* Detect when the reload reg can't hold the reload mode.
4066 This used to be one `if', but Sequent compiler can't handle that. */
4067 if (HARD_REGNO_MODE_OK (regno, reload_mode[r]))
4069 enum machine_mode test_mode = VOIDmode;
4071 test_mode = GET_MODE (reload_in[r]);
4072 /* If reload_in[r] has VOIDmode, it means we will load it
4073 in whatever mode the reload reg has: to wit, reload_mode[r].
4074 We have already tested that for validity. */
4075 /* Aside from that, we need to test that the expressions
4076 to reload from or into have modes which are valid for this
4077 reload register. Otherwise the reload insns would be invalid. */
4078 if (! (reload_in[r] != 0 && test_mode != VOIDmode
4079 && ! HARD_REGNO_MODE_OK (regno, test_mode)))
4080 if (! (reload_out[r] != 0
4081 && ! HARD_REGNO_MODE_OK (regno, GET_MODE (reload_out[r]))))
4082 /* The reg is OK. */
4086 /* The reg is not OK. */
4091 if (asm_noperands (PATTERN (insn)) < 0)
4092 /* It's the compiler's fault. */
4095 /* It's the user's fault; the operand's mode and constraint
4096 don't match. Disable this reload so we don't crash in final. */
4097 error_for_asm (insn,
4098 "`asm' operand constraint incompatible with operand size");
4101 reload_reg_rtx[r] = 0;
4102 reload_optional[r] = 1;
4103 reload_secondary_p[r] = 1;
4108 /* Assign hard reg targets for the pseudo-registers we must reload
4109 into hard regs for this insn.
4110 Also output the instructions to copy them in and out of the hard regs.
4112 For machines with register classes, we are responsible for
4113 finding a reload reg in the proper class. */
4116 choose_reload_regs (insn, avoid_return_reg)
4118 /* This argument is currently ignored. */
4119 rtx avoid_return_reg;
4122 int max_group_size = 1;
4123 enum reg_class group_class = NO_REGS;
4126 rtx save_reload_reg_rtx[MAX_RELOADS];
4127 char save_reload_inherited[MAX_RELOADS];
4128 rtx save_reload_inheritance_insn[MAX_RELOADS];
4129 rtx save_reload_override_in[MAX_RELOADS];
4130 int save_reload_spill_index[MAX_RELOADS];
4131 HARD_REG_SET save_reload_reg_used;
4132 HARD_REG_SET save_reload_reg_used_in_input_addr;
4133 HARD_REG_SET save_reload_reg_used_in_output_addr;
4134 HARD_REG_SET save_reload_reg_used_in_op_addr;
4135 HARD_REG_SET save_reload_reg_used_in_input;
4136 HARD_REG_SET save_reload_reg_used_in_output;
4137 HARD_REG_SET save_reload_reg_used_at_all;
4139 bzero (reload_inherited, MAX_RELOADS);
4140 bzero (reload_inheritance_insn, MAX_RELOADS * sizeof (rtx));
4141 bzero (reload_override_in, MAX_RELOADS * sizeof (rtx));
4143 CLEAR_HARD_REG_SET (reload_reg_used);
4144 CLEAR_HARD_REG_SET (reload_reg_used_at_all);
4145 CLEAR_HARD_REG_SET (reload_reg_used_in_input_addr);
4146 CLEAR_HARD_REG_SET (reload_reg_used_in_output_addr);
4147 CLEAR_HARD_REG_SET (reload_reg_used_in_op_addr);
4148 CLEAR_HARD_REG_SET (reload_reg_used_in_output);
4149 CLEAR_HARD_REG_SET (reload_reg_used_in_input);
4151 /* Distinguish output-only and input-only reloads
4152 because they can overlap with other things. */
4153 for (j = 0; j < n_reloads; j++)
4154 if (reload_when_needed[j] == RELOAD_OTHER
4155 && ! reload_needed_for_multiple[j])
4157 if (reload_in[j] == 0)
4159 /* But earlyclobber operands must stay as RELOAD_OTHER. */
4160 for (i = 0; i < n_earlyclobbers; i++)
4161 if (rtx_equal_p (reload_out[j], reload_earlyclobbers[i]))
4163 if (i == n_earlyclobbers)
4164 reload_when_needed[j] = RELOAD_FOR_OUTPUT;
4166 if (reload_out[j] == 0)
4167 reload_when_needed[j] = RELOAD_FOR_INPUT;
4169 if (reload_secondary_reload[j] >= 0
4170 && ! reload_needed_for_multiple[reload_secondary_reload[j]])
4171 reload_when_needed[reload_secondary_reload[j]]
4172 = reload_when_needed[j];
4175 #ifdef SMALL_REGISTER_CLASSES
4176 /* Don't bother with avoiding the return reg
4177 if we have no mandatory reload that could use it. */
4178 if (avoid_return_reg)
4181 int regno = REGNO (avoid_return_reg);
4183 = HARD_REGNO_NREGS (regno, GET_MODE (avoid_return_reg));
4186 for (r = regno; r < regno + nregs; r++)
4187 if (spill_reg_order[r] >= 0)
4188 for (j = 0; j < n_reloads; j++)
4189 if (!reload_optional[j] && reload_reg_rtx[j] == 0
4190 && (reload_in[j] != 0 || reload_out[j] != 0
4191 || reload_secondary_p[j])
4193 TEST_HARD_REG_BIT (reg_class_contents[(int) reload_reg_class[j]], r))
4196 avoid_return_reg = 0;
4198 #endif /* SMALL_REGISTER_CLASSES */
4200 #if 0 /* Not needed, now that we can always retry without inheritance. */
4201 /* See if we have more mandatory reloads than spill regs.
4202 If so, then we cannot risk optimizations that could prevent
4203 reloads from sharing one spill register.
4205 Since we will try finding a better register than reload_reg_rtx
4206 unless it is equal to reload_in or reload_out, count such reloads. */
4210 #ifdef SMALL_REGISTER_CLASSES
4211 int tem = (avoid_return_reg != 0);
4213 for (j = 0; j < n_reloads; j++)
4214 if (! reload_optional[j]
4215 && (reload_in[j] != 0 || reload_out[j] != 0 || reload_secondary_p[j])
4216 && (reload_reg_rtx[j] == 0
4217 || (! rtx_equal_p (reload_reg_rtx[j], reload_in[j])
4218 && ! rtx_equal_p (reload_reg_rtx[j], reload_out[j]))))
4225 #ifdef SMALL_REGISTER_CLASSES
4226 /* Don't use the subroutine call return reg for a reload
4227 if we are supposed to avoid it. */
4228 if (avoid_return_reg)
4230 int regno = REGNO (avoid_return_reg);
4232 = HARD_REGNO_NREGS (regno, GET_MODE (avoid_return_reg));
4235 for (r = regno; r < regno + nregs; r++)
4236 if (spill_reg_order[r] >= 0)
4237 SET_HARD_REG_BIT (reload_reg_used, r);
4239 #endif /* SMALL_REGISTER_CLASSES */
4241 /* In order to be certain of getting the registers we need,
4242 we must sort the reloads into order of increasing register class.
4243 Then our grabbing of reload registers will parallel the process
4244 that provided the reload registers.
4246 Also note whether any of the reloads wants a consecutive group of regs.
4247 If so, record the maximum size of the group desired and what
4248 register class contains all the groups needed by this insn. */
4250 for (j = 0; j < n_reloads; j++)
4252 reload_order[j] = j;
4253 reload_spill_index[j] = -1;
4256 = (reload_strict_low[j] && reload_out[j]
4257 ? GET_MODE (SUBREG_REG (reload_out[j]))
4258 : (reload_inmode[j] == VOIDmode
4259 || (GET_MODE_SIZE (reload_outmode[j])
4260 > GET_MODE_SIZE (reload_inmode[j])))
4261 ? reload_outmode[j] : reload_inmode[j]);
4263 reload_nregs[j] = CLASS_MAX_NREGS (reload_reg_class[j], reload_mode[j]);
4265 if (reload_nregs[j] > 1)
4267 max_group_size = MAX (reload_nregs[j], max_group_size);
4268 group_class = reg_class_superunion[(int)reload_reg_class[j]][(int)group_class];
4271 /* If we have already decided to use a certain register,
4272 don't use it in another way. */
4273 if (reload_reg_rtx[j])
4274 mark_reload_reg_in_use (REGNO (reload_reg_rtx[j]),
4275 reload_when_needed[j], reload_mode[j]);
4279 qsort (reload_order, n_reloads, sizeof (short), reload_reg_class_lower);
4281 bcopy (reload_reg_rtx, save_reload_reg_rtx, sizeof reload_reg_rtx);
4282 bcopy (reload_inherited, save_reload_inherited, sizeof reload_inherited);
4283 bcopy (reload_inheritance_insn, save_reload_inheritance_insn,
4284 sizeof reload_inheritance_insn);
4285 bcopy (reload_override_in, save_reload_override_in,
4286 sizeof reload_override_in);
4287 bcopy (reload_spill_index, save_reload_spill_index,
4288 sizeof reload_spill_index);
4289 COPY_HARD_REG_SET (save_reload_reg_used, reload_reg_used);
4290 COPY_HARD_REG_SET (save_reload_reg_used_at_all, reload_reg_used_at_all);
4291 COPY_HARD_REG_SET (save_reload_reg_used_in_output,
4292 reload_reg_used_in_output);
4293 COPY_HARD_REG_SET (save_reload_reg_used_in_input,
4294 reload_reg_used_in_input);
4295 COPY_HARD_REG_SET (save_reload_reg_used_in_input_addr,
4296 reload_reg_used_in_input_addr);
4297 COPY_HARD_REG_SET (save_reload_reg_used_in_output_addr,
4298 reload_reg_used_in_output_addr);
4299 COPY_HARD_REG_SET (save_reload_reg_used_in_op_addr,
4300 reload_reg_used_in_op_addr);
4302 /* If -O, try first with inheritance, then turning it off.
4303 If not -O, don't do inheritance.
4304 Using inheritance when not optimizing leads to paradoxes
4305 with fp on the 68k: fp numbers (not NaNs) fail to be equal to themselves
4306 because one side of the comparison might be inherited. */
4308 for (inheritance = optimize > 0; inheritance >= 0; inheritance--)
4310 /* Process the reloads in order of preference just found.
4311 Beyond this point, subregs can be found in reload_reg_rtx.
4313 This used to look for an existing reloaded home for all
4314 of the reloads, and only then perform any new reloads.
4315 But that could lose if the reloads were done out of reg-class order
4316 because a later reload with a looser constraint might have an old
4317 home in a register needed by an earlier reload with a tighter constraint.
4319 To solve this, we make two passes over the reloads, in the order
4320 described above. In the first pass we try to inherit a reload
4321 from a previous insn. If there is a later reload that needs a
4322 class that is a proper subset of the class being processed, we must
4323 also allocate a spill register during the first pass.
4325 Then make a second pass over the reloads to allocate any reloads
4326 that haven't been given registers yet. */
4328 for (j = 0; j < n_reloads; j++)
4330 register int r = reload_order[j];
4332 /* Ignore reloads that got marked inoperative. */
4333 if (reload_out[r] == 0 && reload_in[r] == 0 && ! reload_secondary_p[r])
4336 /* If find_reloads chose a to use reload_in or reload_out as a reload
4337 register, we don't need to chose one. Otherwise, try even if it found
4338 one since we might save an insn if we find the value lying around. */
4339 if (reload_in[r] != 0 && reload_reg_rtx[r] != 0
4340 && (rtx_equal_p (reload_in[r], reload_reg_rtx[r])
4341 || rtx_equal_p (reload_out[r], reload_reg_rtx[r])))
4344 #if 0 /* No longer needed for correct operation.
4345 It might give better code, or might not; worth an experiment? */
4346 /* If this is an optional reload, we can't inherit from earlier insns
4347 until we are sure that any non-optional reloads have been allocated.
4348 The following code takes advantage of the fact that optional reloads
4349 are at the end of reload_order. */
4350 if (reload_optional[r] != 0)
4351 for (i = 0; i < j; i++)
4352 if ((reload_out[reload_order[i]] != 0
4353 || reload_in[reload_order[i]] != 0
4354 || reload_secondary_p[reload_order[i]])
4355 && ! reload_optional[reload_order[i]]
4356 && reload_reg_rtx[reload_order[i]] == 0)
4357 allocate_reload_reg (reload_order[i], insn, 0, inheritance);
4360 /* First see if this pseudo is already available as reloaded
4361 for a previous insn. We cannot try to inherit for reloads
4362 that are smaller than the maximum number of registers needed
4363 for groups unless the register we would allocate cannot be used
4366 We could check here to see if this is a secondary reload for
4367 an object that is already in a register of the desired class.
4368 This would avoid the need for the secondary reload register.
4369 But this is complex because we can't easily determine what
4370 objects might want to be loaded via this reload. So let a register
4371 be allocated here. In `emit_reload_insns' we suppress one of the
4372 loads in the case described above. */
4376 register int regno = -1;
4378 if (reload_in[r] == 0)
4380 else if (GET_CODE (reload_in[r]) == REG)
4381 regno = REGNO (reload_in[r]);
4382 else if (GET_CODE (reload_in_reg[r]) == REG)
4383 regno = REGNO (reload_in_reg[r]);
4385 /* This won't work, since REGNO can be a pseudo reg number.
4386 Also, it takes much more hair to keep track of all the things
4387 that can invalidate an inherited reload of part of a pseudoreg. */
4388 else if (GET_CODE (reload_in[r]) == SUBREG
4389 && GET_CODE (SUBREG_REG (reload_in[r])) == REG)
4390 regno = REGNO (SUBREG_REG (reload_in[r])) + SUBREG_WORD (reload_in[r]);
4393 if (regno >= 0 && reg_last_reload_reg[regno] != 0)
4395 i = spill_reg_order[REGNO (reg_last_reload_reg[regno])];
4397 if (reg_reloaded_contents[i] == regno
4398 && HARD_REGNO_MODE_OK (spill_regs[i], reload_mode[r])
4399 && TEST_HARD_REG_BIT (reg_class_contents[(int) reload_reg_class[r]],
4401 && (reload_nregs[r] == max_group_size
4402 || ! TEST_HARD_REG_BIT (reg_class_contents[(int) group_class],
4404 && reload_reg_free_p (spill_regs[i], reload_when_needed[r])
4405 && reload_reg_free_before_p (spill_regs[i],
4406 reload_when_needed[r]))
4408 /* If a group is needed, verify that all the subsequent
4409 registers still have their values intact. */
4411 = HARD_REGNO_NREGS (spill_regs[i], reload_mode[r]);
4414 for (k = 1; k < nr; k++)
4415 if (reg_reloaded_contents[spill_reg_order[spill_regs[i] + k]]
4421 /* Mark the register as in use for this part of
4423 mark_reload_reg_in_use (spill_regs[i],
4424 reload_when_needed[r],
4426 reload_reg_rtx[r] = reg_last_reload_reg[regno];
4427 reload_inherited[r] = 1;
4428 reload_inheritance_insn[r] = reg_reloaded_insn[i];
4429 reload_spill_index[r] = i;
4435 /* Here's another way to see if the value is already lying around. */
4437 && reload_in[r] != 0
4438 && ! reload_inherited[r]
4439 && reload_out[r] == 0
4440 && (CONSTANT_P (reload_in[r])
4441 || GET_CODE (reload_in[r]) == PLUS
4442 || GET_CODE (reload_in[r]) == REG
4443 || GET_CODE (reload_in[r]) == MEM)
4444 && (reload_nregs[r] == max_group_size
4445 || ! reg_classes_intersect_p (reload_reg_class[r], group_class)))
4448 = find_equiv_reg (reload_in[r], insn, reload_reg_class[r],
4449 -1, NULL_PTR, 0, reload_mode[r]);
4454 if (GET_CODE (equiv) == REG)
4455 regno = REGNO (equiv);
4456 else if (GET_CODE (equiv) == SUBREG)
4458 regno = REGNO (SUBREG_REG (equiv));
4459 if (regno < FIRST_PSEUDO_REGISTER)
4460 regno += SUBREG_WORD (equiv);
4466 /* If we found a spill reg, reject it unless it is free
4467 and of the desired class. */
4469 && ((spill_reg_order[regno] >= 0
4470 && ! reload_reg_free_before_p (regno,
4471 reload_when_needed[r]))
4472 || ! TEST_HARD_REG_BIT (reg_class_contents[(int) reload_reg_class[r]],
4476 if (equiv != 0 && TEST_HARD_REG_BIT (reload_reg_used_at_all, regno))
4479 if (equiv != 0 && ! HARD_REGNO_MODE_OK (regno, reload_mode[r]))
4482 /* We found a register that contains the value we need.
4483 If this register is the same as an `earlyclobber' operand
4484 of the current insn, just mark it as a place to reload from
4485 since we can't use it as the reload register itself. */
4488 for (i = 0; i < n_earlyclobbers; i++)
4489 if (reg_overlap_mentioned_for_reload_p (equiv,
4490 reload_earlyclobbers[i]))
4492 reload_override_in[r] = equiv;
4497 /* JRV: If the equiv register we have found is explicitly
4498 clobbered in the current insn, mark but don't use, as above. */
4500 if (equiv != 0 && regno_clobbered_p (regno, insn))
4502 reload_override_in[r] = equiv;
4506 /* If we found an equivalent reg, say no code need be generated
4507 to load it, and use it as our reload reg. */
4508 if (equiv != 0 && regno != FRAME_POINTER_REGNUM)
4510 reload_reg_rtx[r] = equiv;
4511 reload_inherited[r] = 1;
4512 /* If it is a spill reg,
4513 mark the spill reg as in use for this insn. */
4514 i = spill_reg_order[regno];
4516 mark_reload_reg_in_use (regno, reload_when_needed[r],
4521 /* If we found a register to use already, or if this is an optional
4522 reload, we are done. */
4523 if (reload_reg_rtx[r] != 0 || reload_optional[r] != 0)
4526 #if 0 /* No longer needed for correct operation. Might or might not
4527 give better code on the average. Want to experiment? */
4529 /* See if there is a later reload that has a class different from our
4530 class that intersects our class or that requires less register
4531 than our reload. If so, we must allocate a register to this
4532 reload now, since that reload might inherit a previous reload
4533 and take the only available register in our class. Don't do this
4534 for optional reloads since they will force all previous reloads
4535 to be allocated. Also don't do this for reloads that have been
4538 for (i = j + 1; i < n_reloads; i++)
4540 int s = reload_order[i];
4542 if ((reload_in[s] == 0 && reload_out[s] == 0
4543 && ! reload_secondary_p[s])
4544 || reload_optional[s])
4547 if ((reload_reg_class[s] != reload_reg_class[r]
4548 && reg_classes_intersect_p (reload_reg_class[r],
4549 reload_reg_class[s]))
4550 || reload_nregs[s] < reload_nregs[r])
4557 allocate_reload_reg (r, insn, j == n_reloads - 1, inheritance);
4561 /* Now allocate reload registers for anything non-optional that
4562 didn't get one yet. */
4563 for (j = 0; j < n_reloads; j++)
4565 register int r = reload_order[j];
4567 /* Ignore reloads that got marked inoperative. */
4568 if (reload_out[r] == 0 && reload_in[r] == 0 && ! reload_secondary_p[r])
4571 /* Skip reloads that already have a register allocated or are
4573 if (reload_reg_rtx[r] != 0 || reload_optional[r])
4576 if (! allocate_reload_reg (r, insn, j == n_reloads - 1, inheritance))
4580 /* If that loop got all the way, we have won. */
4585 /* Loop around and try without any inheritance. */
4586 /* First undo everything done by the failed attempt
4587 to allocate with inheritance. */
4588 bcopy (save_reload_reg_rtx, reload_reg_rtx, sizeof reload_reg_rtx);
4589 bcopy (save_reload_inherited, reload_inherited, sizeof reload_inherited);
4590 bcopy (save_reload_inheritance_insn, reload_inheritance_insn,
4591 sizeof reload_inheritance_insn);
4592 bcopy (save_reload_override_in, reload_override_in,
4593 sizeof reload_override_in);
4594 bcopy (save_reload_spill_index, reload_spill_index,
4595 sizeof reload_spill_index);
4596 COPY_HARD_REG_SET (reload_reg_used, save_reload_reg_used);
4597 COPY_HARD_REG_SET (reload_reg_used_at_all, save_reload_reg_used_at_all);
4598 COPY_HARD_REG_SET (reload_reg_used_in_input,
4599 save_reload_reg_used_in_input);
4600 COPY_HARD_REG_SET (reload_reg_used_in_output,
4601 save_reload_reg_used_in_output);
4602 COPY_HARD_REG_SET (reload_reg_used_in_input_addr,
4603 save_reload_reg_used_in_input_addr);
4604 COPY_HARD_REG_SET (reload_reg_used_in_output_addr,
4605 save_reload_reg_used_in_output_addr);
4606 COPY_HARD_REG_SET (reload_reg_used_in_op_addr,
4607 save_reload_reg_used_in_op_addr);
4610 /* If we thought we could inherit a reload, because it seemed that
4611 nothing else wanted the same reload register earlier in the insn,
4612 verify that assumption, now that all reloads have been assigned. */
4614 for (j = 0; j < n_reloads; j++)
4616 register int r = reload_order[j];
4618 if (reload_inherited[r] && reload_reg_rtx[r] != 0
4619 && ! reload_reg_free_before_p (true_regnum (reload_reg_rtx[r]),
4620 reload_when_needed[r]))
4621 reload_inherited[r] = 0;
4623 /* If we found a better place to reload from,
4624 validate it in the same fashion, if it is a reload reg. */
4625 if (reload_override_in[r]
4626 && (GET_CODE (reload_override_in[r]) == REG
4627 || GET_CODE (reload_override_in[r]) == SUBREG))
4629 int regno = true_regnum (reload_override_in[r]);
4630 if (spill_reg_order[regno] >= 0
4631 && ! reload_reg_free_before_p (regno, reload_when_needed[r]))
4632 reload_override_in[r] = 0;
4636 /* Now that reload_override_in is known valid,
4637 actually override reload_in. */
4638 for (j = 0; j < n_reloads; j++)
4639 if (reload_override_in[j])
4640 reload_in[j] = reload_override_in[j];
4642 /* If this reload won't be done because it has been cancelled or is
4643 optional and not inherited, clear reload_reg_rtx so other
4644 routines (such as subst_reloads) don't get confused. */
4645 for (j = 0; j < n_reloads; j++)
4646 if ((reload_optional[j] && ! reload_inherited[j])
4647 || (reload_in[j] == 0 && reload_out[j] == 0
4648 && ! reload_secondary_p[j]))
4649 reload_reg_rtx[j] = 0;
4651 /* Record which pseudos and which spill regs have output reloads. */
4652 for (j = 0; j < n_reloads; j++)
4654 register int r = reload_order[j];
4656 i = reload_spill_index[r];
4658 /* I is nonneg if this reload used one of the spill regs.
4659 If reload_reg_rtx[r] is 0, this is an optional reload
4660 that we opted to ignore. */
4661 if (reload_out[r] != 0 && GET_CODE (reload_out[r]) == REG
4662 && reload_reg_rtx[r] != 0)
4664 register int nregno = REGNO (reload_out[r]);
4667 if (nregno < FIRST_PSEUDO_REGISTER)
4668 nr = HARD_REGNO_NREGS (nregno, reload_mode[r]);
4671 reg_has_output_reload[nregno + nr] = 1;
4675 nr = HARD_REGNO_NREGS (spill_regs[i], reload_mode[r]);
4677 SET_HARD_REG_BIT (reg_is_output_reload, spill_regs[i] + nr);
4680 if (reload_when_needed[r] != RELOAD_OTHER
4681 && reload_when_needed[r] != RELOAD_FOR_OUTPUT)
4687 /* Output insns to reload values in and out of the chosen reload regs. */
4690 emit_reload_insns (insn)
4694 rtx following_insn = NEXT_INSN (insn);
4695 rtx before_insn = insn;
4696 rtx first_output_reload_insn = NEXT_INSN (insn);
4697 rtx first_other_reload_insn = insn;
4698 rtx first_operand_address_reload_insn = insn;
4700 /* Values to be put in spill_reg_store are put here first. */
4701 rtx new_spill_reg_store[FIRST_PSEUDO_REGISTER];
4703 /* If this is a CALL_INSN preceded by USE insns, any reload insns
4704 must go in front of the first USE insn, not in front of INSN. */
4706 if (GET_CODE (insn) == CALL_INSN && GET_CODE (PREV_INSN (insn)) == INSN
4707 && GET_CODE (PATTERN (PREV_INSN (insn))) == USE)
4708 while (GET_CODE (PREV_INSN (before_insn)) == INSN
4709 && GET_CODE (PATTERN (PREV_INSN (before_insn))) == USE)
4710 first_other_reload_insn = first_operand_address_reload_insn
4711 = before_insn = PREV_INSN (before_insn);
4713 /* Now output the instructions to copy the data into and out of the
4714 reload registers. Do these in the order that the reloads were reported,
4715 since reloads of base and index registers precede reloads of operands
4716 and the operands may need the base and index registers reloaded. */
4718 for (j = 0; j < n_reloads; j++)
4721 rtx oldequiv_reg = 0;
4722 rtx this_reload_insn = 0;
4726 if (old != 0 && ! reload_inherited[j]
4727 && ! rtx_equal_p (reload_reg_rtx[j], old)
4728 && reload_reg_rtx[j] != 0)
4730 register rtx reloadreg = reload_reg_rtx[j];
4732 enum machine_mode mode;
4736 /* Determine the mode to reload in.
4737 This is very tricky because we have three to choose from.
4738 There is the mode the insn operand wants (reload_inmode[J]).
4739 There is the mode of the reload register RELOADREG.
4740 There is the intrinsic mode of the operand, which we could find
4741 by stripping some SUBREGs.
4742 It turns out that RELOADREG's mode is irrelevant:
4743 we can change that arbitrarily.
4745 Consider (SUBREG:SI foo:QI) as an operand that must be SImode;
4746 then the reload reg may not support QImode moves, so use SImode.
4747 If foo is in memory due to spilling a pseudo reg, this is safe,
4748 because the QImode value is in the least significant part of a
4749 slot big enough for a SImode. If foo is some other sort of
4750 memory reference, then it is impossible to reload this case,
4751 so previous passes had better make sure this never happens.
4753 Then consider a one-word union which has SImode and one of its
4754 members is a float, being fetched as (SUBREG:SF union:SI).
4755 We must fetch that as SFmode because we could be loading into
4756 a float-only register. In this case OLD's mode is correct.
4758 Consider an immediate integer: it has VOIDmode. Here we need
4759 to get a mode from something else.
4761 In some cases, there is a fourth mode, the operand's
4762 containing mode. If the insn specifies a containing mode for
4763 this operand, it overrides all others.
4765 I am not sure whether the algorithm here is always right,
4766 but it does the right things in those cases. */
4768 mode = GET_MODE (old);
4769 if (mode == VOIDmode)
4770 mode = reload_inmode[j];
4771 if (reload_strict_low[j])
4772 mode = GET_MODE (SUBREG_REG (reload_in[j]));
4774 #ifdef SECONDARY_INPUT_RELOAD_CLASS
4775 /* If we need a secondary register for this operation, see if
4776 the value is already in a register in that class. Don't
4777 do this if the secondary register will be used as a scratch
4780 if (reload_secondary_reload[j] >= 0
4781 && reload_secondary_icode[j] == CODE_FOR_nothing
4784 = find_equiv_reg (old, insn,
4785 reload_reg_class[reload_secondary_reload[j]],
4786 -1, NULL_PTR, 0, mode);
4789 /* If reloading from memory, see if there is a register
4790 that already holds the same value. If so, reload from there.
4791 We can pass 0 as the reload_reg_p argument because
4792 any other reload has either already been emitted,
4793 in which case find_equiv_reg will see the reload-insn,
4794 or has yet to be emitted, in which case it doesn't matter
4795 because we will use this equiv reg right away. */
4797 if (oldequiv == 0 && optimize
4798 && (GET_CODE (old) == MEM
4799 || (GET_CODE (old) == REG
4800 && REGNO (old) >= FIRST_PSEUDO_REGISTER
4801 && reg_renumber[REGNO (old)] < 0)))
4802 oldequiv = find_equiv_reg (old, insn, GENERAL_REGS,
4803 -1, NULL_PTR, 0, mode);
4807 int regno = true_regnum (oldequiv);
4809 /* If OLDEQUIV is a spill register, don't use it for this
4810 if any other reload needs it at an earlier stage of this insn
4811 or at this stage. */
4812 if (spill_reg_order[regno] >= 0
4813 && (! reload_reg_free_p (regno, reload_when_needed[j])
4814 || ! reload_reg_free_before_p (regno,
4815 reload_when_needed[j])))
4818 /* If OLDEQUIV is not a spill register,
4819 don't use it if any other reload wants it. */
4820 if (spill_reg_order[regno] < 0)
4823 for (k = 0; k < n_reloads; k++)
4824 if (reload_reg_rtx[k] != 0 && k != j
4825 && reg_overlap_mentioned_for_reload_p (reload_reg_rtx[k],
4836 else if (GET_CODE (oldequiv) == REG)
4837 oldequiv_reg = oldequiv;
4838 else if (GET_CODE (oldequiv) == SUBREG)
4839 oldequiv_reg = SUBREG_REG (oldequiv);
4841 /* Encapsulate both RELOADREG and OLDEQUIV into that mode,
4842 then load RELOADREG from OLDEQUIV. */
4844 if (GET_MODE (reloadreg) != mode)
4845 reloadreg = gen_rtx (REG, mode, REGNO (reloadreg));
4846 while (GET_CODE (oldequiv) == SUBREG && GET_MODE (oldequiv) != mode)
4847 oldequiv = SUBREG_REG (oldequiv);
4848 if (GET_MODE (oldequiv) != VOIDmode
4849 && mode != GET_MODE (oldequiv))
4850 oldequiv = gen_rtx (SUBREG, mode, oldequiv, 0);
4852 /* Decide where to put reload insn for this reload. */
4853 switch (reload_when_needed[j])
4855 case RELOAD_FOR_INPUT:
4857 where = first_operand_address_reload_insn;
4859 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
4860 where = first_other_reload_insn;
4862 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
4863 where = first_output_reload_insn;
4865 case RELOAD_FOR_OPERAND_ADDRESS:
4866 where = before_insn;
4871 /* Auto-increment addresses must be reloaded in a special way. */
4872 if (GET_CODE (oldequiv) == POST_INC
4873 || GET_CODE (oldequiv) == POST_DEC
4874 || GET_CODE (oldequiv) == PRE_INC
4875 || GET_CODE (oldequiv) == PRE_DEC)
4877 /* We are not going to bother supporting the case where a
4878 incremented register can't be copied directly from
4879 OLDEQUIV since this seems highly unlikely. */
4880 if (reload_secondary_reload[j] >= 0)
4882 /* Prevent normal processing of this reload. */
4884 /* Output a special code sequence for this case. */
4886 = inc_for_reload (reloadreg, oldequiv, reload_inc[j], where);
4889 /* If we are reloading a pseudo-register that was set by the previous
4890 insn, see if we can get rid of that pseudo-register entirely
4891 by redirecting the previous insn into our reload register. */
4893 else if (optimize && GET_CODE (old) == REG
4894 && REGNO (old) >= FIRST_PSEUDO_REGISTER
4895 && dead_or_set_p (insn, old)
4896 /* This is unsafe if some other reload
4897 uses the same reg first. */
4898 && (reload_when_needed[j] == RELOAD_OTHER
4899 || reload_when_needed[j] == RELOAD_FOR_INPUT
4900 || reload_when_needed[j] == RELOAD_FOR_INPUT_RELOAD_ADDRESS))
4902 rtx temp = PREV_INSN (insn);
4903 while (temp && GET_CODE (temp) == NOTE)
4904 temp = PREV_INSN (temp);
4906 && GET_CODE (temp) == INSN
4907 && GET_CODE (PATTERN (temp)) == SET
4908 && SET_DEST (PATTERN (temp)) == old
4909 /* Make sure we can access insn_operand_constraint. */
4910 && asm_noperands (PATTERN (temp)) < 0
4911 /* This is unsafe if prev insn rejects our reload reg. */
4912 && constraint_accepts_reg_p (insn_operand_constraint[recog_memoized (temp)][0],
4914 /* This is unsafe if operand occurs more than once in current
4915 insn. Perhaps some occurrences aren't reloaded. */
4916 && count_occurrences (PATTERN (insn), old) == 1
4917 /* Don't risk splitting a matching pair of operands. */
4918 && ! reg_mentioned_p (old, SET_SRC (PATTERN (temp))))
4920 /* Store into the reload register instead of the pseudo. */
4921 SET_DEST (PATTERN (temp)) = reloadreg;
4922 /* If these are the only uses of the pseudo reg,
4923 pretend for GDB it lives in the reload reg we used. */
4924 if (reg_n_deaths[REGNO (old)] == 1
4925 && reg_n_sets[REGNO (old)] == 1)
4927 reg_renumber[REGNO (old)] = REGNO (reload_reg_rtx[j]);
4928 alter_reg (REGNO (old), -1);
4934 /* We can't do that, so output an insn to load RELOADREG.
4935 Keep them in the following order:
4936 all reloads for input reload addresses,
4937 all reloads for ordinary input operands,
4938 all reloads for addresses of non-reloaded operands,
4939 the insn being reloaded,
4940 all reloads for addresses of output reloads,
4941 the output reloads. */
4944 #ifdef SECONDARY_INPUT_RELOAD_CLASS
4945 rtx second_reload_reg = 0;
4946 enum insn_code icode;
4948 /* If we have a secondary reload, pick up the secondary register
4949 and icode, if any. If OLDEQUIV and OLD are different or
4950 if this is an in-out reload, recompute whether or not we
4951 still need a secondary register and what the icode should
4952 be. If we still need a secondary register and the class or
4953 icode is different, go back to reloading from OLD if using
4954 OLDEQUIV means that we got the wrong type of register. We
4955 cannot have different class or icode due to an in-out reload
4956 because we don't make such reloads when both the input and
4957 output need secondary reload registers. */
4959 if (reload_secondary_reload[j] >= 0)
4961 int secondary_reload = reload_secondary_reload[j];
4962 rtx real_oldequiv = oldequiv;
4965 /* If OLDEQUIV is a pseudo with a MEM, get the real MEM
4966 and similarly for OLD.
4967 See comments in find_secondary_reload in reload.c. */
4968 if (GET_CODE (oldequiv) == REG
4969 && REGNO (oldequiv) >= FIRST_PSEUDO_REGISTER
4970 && reg_equiv_mem[REGNO (oldequiv)] != 0)
4971 real_oldequiv = reg_equiv_mem[REGNO (oldequiv)];
4973 if (GET_CODE (old) == REG
4974 && REGNO (old) >= FIRST_PSEUDO_REGISTER
4975 && reg_equiv_mem[REGNO (old)] != 0)
4976 real_old = reg_equiv_mem[REGNO (old)];
4978 second_reload_reg = reload_reg_rtx[secondary_reload];
4979 icode = reload_secondary_icode[j];
4981 if ((old != oldequiv && ! rtx_equal_p (old, oldequiv))
4982 || (reload_in[j] != 0 && reload_out[j] != 0))
4984 enum reg_class new_class
4985 = SECONDARY_INPUT_RELOAD_CLASS (reload_reg_class[j],
4986 mode, real_oldequiv);
4988 if (new_class == NO_REGS)
4989 second_reload_reg = 0;
4992 enum insn_code new_icode;
4993 enum machine_mode new_mode;
4995 if (! TEST_HARD_REG_BIT (reg_class_contents[(int) new_class],
4996 REGNO (second_reload_reg)))
4997 oldequiv = old, real_oldequiv = real_old;
5000 new_icode = reload_in_optab[(int) mode];
5001 if (new_icode != CODE_FOR_nothing
5002 && ((insn_operand_predicate[(int) new_icode][0]
5003 && ! ((*insn_operand_predicate[(int) new_icode][0])
5005 || (insn_operand_predicate[(int) new_icode][1]
5006 && ! ((*insn_operand_predicate[(int) new_icode][1])
5007 (real_oldequiv, mode)))))
5008 new_icode = CODE_FOR_nothing;
5010 if (new_icode == CODE_FOR_nothing)
5013 new_mode = insn_operand_mode[new_icode][2];
5015 if (GET_MODE (second_reload_reg) != new_mode)
5017 if (!HARD_REGNO_MODE_OK (REGNO (second_reload_reg),
5019 oldequiv = old, real_oldequiv = real_old;
5022 = gen_rtx (REG, new_mode,
5023 REGNO (second_reload_reg));
5029 /* If we still need a secondary reload register, check
5030 to see if it is being used as a scratch or intermediate
5031 register and generate code appropriately. If we need
5032 a scratch register, use REAL_OLDEQUIV since the form of
5033 the insn may depend on the actual address if it is
5036 if (second_reload_reg)
5038 if (icode != CODE_FOR_nothing)
5040 reload_insn = emit_insn_before (GEN_FCN (icode)
5045 if (this_reload_insn == 0)
5046 this_reload_insn = reload_insn;
5051 /* See if we need a scratch register to load the
5052 intermediate register (a tertiary reload). */
5053 enum insn_code tertiary_icode
5054 = reload_secondary_icode[secondary_reload];
5056 if (tertiary_icode != CODE_FOR_nothing)
5058 rtx third_reload_reg
5059 = reload_reg_rtx[reload_secondary_reload[secondary_reload]];
5062 = emit_insn_before ((GEN_FCN (tertiary_icode)
5067 if (this_reload_insn == 0)
5068 this_reload_insn = reload_insn;
5073 = gen_input_reload (second_reload_reg,
5075 if (this_reload_insn == 0)
5076 this_reload_insn = reload_insn;
5077 oldequiv = second_reload_reg;
5086 reload_insn = gen_input_reload (reloadreg, oldequiv, where);
5087 if (this_reload_insn == 0)
5088 this_reload_insn = reload_insn;
5091 #if defined(SECONDARY_INPUT_RELOAD_CLASS) && defined(PRESERVE_DEATH_INFO_REGNO_P)
5092 /* We may have to make a REG_DEAD note for the secondary reload
5093 register in the insns we just made. Find the last insn that
5094 mentioned the register. */
5095 if (! special && second_reload_reg
5096 && PRESERVE_DEATH_INFO_REGNO_P (REGNO (second_reload_reg)))
5101 prev != PREV_INSN (this_reload_insn);
5102 prev = PREV_INSN (prev))
5103 if (GET_RTX_CLASS (GET_CODE (prev) == 'i')
5104 && reg_overlap_mentioned_for_reload_p (second_reload_reg,
5107 REG_NOTES (prev) = gen_rtx (EXPR_LIST, REG_DEAD,
5116 /* Update where to put other reload insns. */
5117 if (this_reload_insn)
5118 switch (reload_when_needed[j])
5120 case RELOAD_FOR_INPUT:
5122 if (first_other_reload_insn == first_operand_address_reload_insn)
5123 first_other_reload_insn = this_reload_insn;
5125 case RELOAD_FOR_OPERAND_ADDRESS:
5126 if (first_operand_address_reload_insn == before_insn)
5127 first_operand_address_reload_insn = this_reload_insn;
5128 if (first_other_reload_insn == before_insn)
5129 first_other_reload_insn = this_reload_insn;
5132 /* reload_inc[j] was formerly processed here. */
5135 /* Add a note saying the input reload reg
5136 dies in this insn, if anyone cares. */
5137 #ifdef PRESERVE_DEATH_INFO_REGNO_P
5139 && reload_reg_rtx[j] != old
5140 && reload_reg_rtx[j] != 0
5141 && reload_out[j] == 0
5142 && ! reload_inherited[j]
5143 && PRESERVE_DEATH_INFO_REGNO_P (REGNO (reload_reg_rtx[j])))
5145 register rtx reloadreg = reload_reg_rtx[j];
5148 /* We can't abort here because we need to support this for sched.c.
5149 It's not terrible to miss a REG_DEAD note, but we should try
5150 to figure out how to do this correctly. */
5151 /* The code below is incorrect for address-only reloads. */
5152 if (reload_when_needed[j] != RELOAD_OTHER
5153 && reload_when_needed[j] != RELOAD_FOR_INPUT)
5157 /* Add a death note to this insn, for an input reload. */
5159 if ((reload_when_needed[j] == RELOAD_OTHER
5160 || reload_when_needed[j] == RELOAD_FOR_INPUT)
5161 && ! dead_or_set_p (insn, reloadreg))
5163 = gen_rtx (EXPR_LIST, REG_DEAD,
5164 reloadreg, REG_NOTES (insn));
5167 /* When we inherit a reload, the last marked death of the reload reg
5168 may no longer really be a death. */
5169 if (reload_reg_rtx[j] != 0
5170 && PRESERVE_DEATH_INFO_REGNO_P (REGNO (reload_reg_rtx[j]))
5171 && reload_inherited[j])
5173 /* Handle inheriting an output reload.
5174 Remove the death note from the output reload insn. */
5175 if (reload_spill_index[j] >= 0
5176 && GET_CODE (reload_in[j]) == REG
5177 && spill_reg_store[reload_spill_index[j]] != 0
5178 && find_regno_note (spill_reg_store[reload_spill_index[j]],
5179 REG_DEAD, REGNO (reload_reg_rtx[j])))
5180 remove_death (REGNO (reload_reg_rtx[j]),
5181 spill_reg_store[reload_spill_index[j]]);
5182 /* Likewise for input reloads that were inherited. */
5183 else if (reload_spill_index[j] >= 0
5184 && GET_CODE (reload_in[j]) == REG
5185 && spill_reg_store[reload_spill_index[j]] == 0
5186 && reload_inheritance_insn[j] != 0
5187 && find_regno_note (reload_inheritance_insn[j], REG_DEAD,
5188 REGNO (reload_reg_rtx[j])))
5189 remove_death (REGNO (reload_reg_rtx[j]),
5190 reload_inheritance_insn[j]);
5195 /* We got this register from find_equiv_reg.
5196 Search back for its last death note and get rid of it.
5197 But don't search back too far.
5198 Don't go past a place where this reg is set,
5199 since a death note before that remains valid. */
5200 for (prev = PREV_INSN (insn);
5201 prev && GET_CODE (prev) != CODE_LABEL;
5202 prev = PREV_INSN (prev))
5203 if (GET_RTX_CLASS (GET_CODE (prev)) == 'i'
5204 && dead_or_set_p (prev, reload_reg_rtx[j]))
5206 if (find_regno_note (prev, REG_DEAD,
5207 REGNO (reload_reg_rtx[j])))
5208 remove_death (REGNO (reload_reg_rtx[j]), prev);
5214 /* We might have used find_equiv_reg above to choose an alternate
5215 place from which to reload. If so, and it died, we need to remove
5216 that death and move it to one of the insns we just made. */
5218 if (oldequiv_reg != 0
5219 && PRESERVE_DEATH_INFO_REGNO_P (true_regnum (oldequiv_reg)))
5223 for (prev = PREV_INSN (insn); prev && GET_CODE (prev) != CODE_LABEL;
5224 prev = PREV_INSN (prev))
5225 if (GET_RTX_CLASS (GET_CODE (prev)) == 'i'
5226 && dead_or_set_p (prev, oldequiv_reg))
5228 if (find_regno_note (prev, REG_DEAD, REGNO (oldequiv_reg)))
5230 for (prev1 = this_reload_insn;
5231 prev1; prev1 = PREV_INSN (prev1))
5232 if (GET_RTX_CLASS (GET_CODE (prev1) == 'i')
5233 && reg_overlap_mentioned_for_reload_p (oldequiv_reg,
5236 REG_NOTES (prev1) = gen_rtx (EXPR_LIST, REG_DEAD,
5241 remove_death (REGNO (oldequiv_reg), prev);
5248 /* If we are reloading a register that was recently stored in with an
5249 output-reload, see if we can prove there was
5250 actually no need to store the old value in it. */
5252 if (optimize && reload_inherited[j] && reload_spill_index[j] >= 0
5253 /* This is unsafe if some other reload uses the same reg first. */
5254 && (reload_when_needed[j] == RELOAD_OTHER
5255 || reload_when_needed[j] == RELOAD_FOR_INPUT
5256 || reload_when_needed[j] == RELOAD_FOR_INPUT_RELOAD_ADDRESS)
5257 && GET_CODE (reload_in[j]) == REG
5259 /* There doesn't seem to be any reason to restrict this to pseudos
5260 and doing so loses in the case where we are copying from a
5261 register of the wrong class. */
5262 && REGNO (reload_in[j]) >= FIRST_PSEUDO_REGISTER
5264 && spill_reg_store[reload_spill_index[j]] != 0
5265 && dead_or_set_p (insn, reload_in[j])
5266 /* This is unsafe if operand occurs more than once in current
5267 insn. Perhaps some occurrences weren't reloaded. */
5268 && count_occurrences (PATTERN (insn), reload_in[j]) == 1)
5269 delete_output_reload (insn, j,
5270 spill_reg_store[reload_spill_index[j]]);
5272 /* Input-reloading is done. Now do output-reloading,
5273 storing the value from the reload-register after the main insn
5274 if reload_out[j] is nonzero.
5276 ??? At some point we need to support handling output reloads of
5277 JUMP_INSNs or insns that set cc0. */
5278 old = reload_out[j];
5280 && reload_reg_rtx[j] != old
5281 && reload_reg_rtx[j] != 0)
5283 register rtx reloadreg = reload_reg_rtx[j];
5284 register rtx second_reloadreg = 0;
5285 rtx prev_insn = PREV_INSN (first_output_reload_insn);
5287 enum machine_mode mode;
5290 /* An output operand that dies right away does need a reload,
5291 but need not be copied from it. Show the new location in the
5293 if ((GET_CODE (old) == REG || GET_CODE (old) == SCRATCH)
5294 && (note = find_reg_note (insn, REG_UNUSED, old)) != 0)
5296 XEXP (note, 0) = reload_reg_rtx[j];
5299 else if (GET_CODE (old) == SCRATCH)
5300 /* If we aren't optimizing, there won't be a REG_UNUSED note,
5301 but we don't want to make an output reload. */
5305 /* Strip off of OLD any size-increasing SUBREGs such as
5306 (SUBREG:SI foo:QI 0). */
5308 while (GET_CODE (old) == SUBREG && SUBREG_WORD (old) == 0
5309 && (GET_MODE_SIZE (GET_MODE (old))
5310 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (old)))))
5311 old = SUBREG_REG (old);
5314 /* If is a JUMP_INSN, we can't support output reloads yet. */
5315 if (GET_CODE (insn) == JUMP_INSN)
5318 /* Determine the mode to reload in.
5319 See comments above (for input reloading). */
5321 mode = GET_MODE (old);
5322 if (mode == VOIDmode)
5323 abort (); /* Should never happen for an output. */
5325 /* A strict-low-part output operand needs to be reloaded
5326 in the mode of the entire value. */
5327 if (reload_strict_low[j])
5329 mode = GET_MODE (SUBREG_REG (reload_out[j]));
5330 /* Encapsulate OLD into that mode. */
5331 /* If OLD is a subreg, then strip it, since the subreg will
5332 be altered by this very reload. */
5333 while (GET_CODE (old) == SUBREG && GET_MODE (old) != mode)
5334 old = SUBREG_REG (old);
5335 if (GET_MODE (old) != VOIDmode
5336 && mode != GET_MODE (old))
5337 old = gen_rtx (SUBREG, mode, old, 0);
5340 if (GET_MODE (reloadreg) != mode)
5341 reloadreg = gen_rtx (REG, mode, REGNO (reloadreg));
5343 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
5345 /* If we need two reload regs, set RELOADREG to the intermediate
5346 one, since it will be stored into OUT. We might need a secondary
5347 register only for an input reload, so check again here. */
5349 if (reload_secondary_reload[j] >= 0)
5353 if (GET_CODE (old) == REG && REGNO (old) >= FIRST_PSEUDO_REGISTER
5354 && reg_equiv_mem[REGNO (old)] != 0)
5355 real_old = reg_equiv_mem[REGNO (old)];
5357 if((SECONDARY_OUTPUT_RELOAD_CLASS (reload_reg_class[j],
5361 second_reloadreg = reloadreg;
5362 reloadreg = reload_reg_rtx[reload_secondary_reload[j]];
5364 /* See if RELOADREG is to be used as a scratch register
5365 or as an intermediate register. */
5366 if (reload_secondary_icode[j] != CODE_FOR_nothing)
5368 emit_insn_before ((GEN_FCN (reload_secondary_icode[j])
5369 (real_old, second_reloadreg,
5371 first_output_reload_insn);
5376 /* See if we need both a scratch and intermediate reload
5378 int secondary_reload = reload_secondary_reload[j];
5379 enum insn_code tertiary_icode
5380 = reload_secondary_icode[secondary_reload];
5383 if (GET_MODE (reloadreg) != mode)
5384 reloadreg = gen_rtx (REG, mode, REGNO (reloadreg));
5386 if (tertiary_icode != CODE_FOR_nothing)
5389 = reload_reg_rtx[reload_secondary_reload[secondary_reload]];
5390 pat = (GEN_FCN (tertiary_icode)
5391 (reloadreg, second_reloadreg, third_reloadreg));
5393 #ifdef SECONDARY_MEMORY_NEEDED
5394 /* If we need a memory location to do the move, do it that way. */
5395 else if (GET_CODE (reloadreg) == REG
5396 && REGNO (reloadreg) < FIRST_PSEUDO_REGISTER
5397 && SECONDARY_MEMORY_NEEDED (REGNO_REG_CLASS (REGNO (reloadreg)),
5398 REGNO_REG_CLASS (REGNO (second_reloadreg)),
5399 GET_MODE (second_reloadreg)))
5401 /* Get the memory to use and rewrite both registers
5403 rtx loc = get_secondary_mem (reloadreg,
5404 GET_MODE (second_reloadreg));
5407 if (GET_MODE (loc) != GET_MODE (second_reloadreg))
5408 second_reloadreg = gen_rtx (REG, GET_MODE (loc),
5409 REGNO (second_reloadreg));
5411 if (GET_MODE (loc) != GET_MODE (reloadreg))
5412 tmp_reloadreg = gen_rtx (REG, GET_MODE (loc),
5415 tmp_reloadreg = reloadreg;
5417 emit_insn_before (gen_move_insn (loc, second_reloadreg),
5418 first_output_reload_insn);
5419 pat = gen_move_insn (tmp_reloadreg, loc);
5423 pat = gen_move_insn (reloadreg, second_reloadreg);
5425 emit_insn_before (pat, first_output_reload_insn);
5431 /* Output the last reload insn. */
5434 #ifdef SECONDARY_MEMORY_NEEDED
5435 /* If we need a memory location to do the move, do it that way. */
5436 if (GET_CODE (old) == REG && REGNO (old) < FIRST_PSEUDO_REGISTER
5437 && SECONDARY_MEMORY_NEEDED (REGNO_REG_CLASS (REGNO (old)),
5438 REGNO_REG_CLASS (REGNO (reloadreg)),
5439 GET_MODE (reloadreg)))
5441 /* Get the memory to use and rewrite both registers to
5443 rtx loc = get_secondary_mem (old, GET_MODE (reloadreg));
5445 if (GET_MODE (loc) != GET_MODE (reloadreg))
5446 reloadreg = gen_rtx (REG, GET_MODE (loc),
5449 if (GET_MODE (loc) != GET_MODE (old))
5450 old = gen_rtx (REG, GET_MODE (loc), REGNO (old));
5452 emit_insn_before (gen_move_insn (loc, reloadreg),
5453 first_output_reload_insn);
5454 emit_insn_before (gen_move_insn (old, loc),
5455 first_output_reload_insn);
5459 emit_insn_before (gen_move_insn (old, reloadreg),
5460 first_output_reload_insn);
5463 #ifdef PRESERVE_DEATH_INFO_REGNO_P
5464 /* If final will look at death notes for this reg,
5465 put one on the last output-reload insn to use it. Similarly
5466 for any secondary register. */
5467 if (PRESERVE_DEATH_INFO_REGNO_P (REGNO (reloadreg)))
5468 for (p = PREV_INSN (first_output_reload_insn);
5469 p != prev_insn; p = PREV_INSN (p))
5470 if (GET_RTX_CLASS (GET_CODE (p)) == 'i'
5471 && reg_overlap_mentioned_for_reload_p (reloadreg,
5473 REG_NOTES (p) = gen_rtx (EXPR_LIST, REG_DEAD,
5474 reloadreg, REG_NOTES (p));
5476 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
5478 && PRESERVE_DEATH_INFO_REGNO_P (REGNO (second_reloadreg)))
5479 for (p = PREV_INSN (first_output_reload_insn);
5480 p != prev_insn; p = PREV_INSN (p))
5481 if (GET_RTX_CLASS (GET_CODE (p)) == 'i'
5482 && reg_overlap_mentioned_for_reload_p (second_reloadreg,
5484 REG_NOTES (p) = gen_rtx (EXPR_LIST, REG_DEAD,
5485 second_reloadreg, REG_NOTES (p));
5488 /* Look at all insns we emitted, just to be safe. */
5489 for (p = NEXT_INSN (prev_insn); p != first_output_reload_insn;
5491 if (GET_RTX_CLASS (GET_CODE (p)) == 'i')
5493 /* If this output reload doesn't come from a spill reg,
5494 clear any memory of reloaded copies of the pseudo reg.
5495 If this output reload comes from a spill reg,
5496 reg_has_output_reload will make this do nothing. */
5497 note_stores (PATTERN (p), forget_old_reloads_1);
5499 if (reg_mentioned_p (reload_reg_rtx[j], PATTERN (p)))
5503 first_output_reload_insn = NEXT_INSN (prev_insn);
5506 if (reload_spill_index[j] >= 0)
5507 new_spill_reg_store[reload_spill_index[j]] = store_insn;
5510 /* Move death notes from INSN
5511 to output-operand-address and output reload insns. */
5512 #ifdef PRESERVE_DEATH_INFO_REGNO_P
5515 /* Loop over those insns, last ones first. */
5516 for (insn1 = PREV_INSN (following_insn); insn1 != insn;
5517 insn1 = PREV_INSN (insn1))
5518 if (GET_CODE (insn1) == INSN && GET_CODE (PATTERN (insn1)) == SET)
5520 rtx source = SET_SRC (PATTERN (insn1));
5521 rtx dest = SET_DEST (PATTERN (insn1));
5523 /* The note we will examine next. */
5524 rtx reg_notes = REG_NOTES (insn);
5525 /* The place that pointed to this note. */
5526 rtx *prev_reg_note = ®_NOTES (insn);
5528 /* If the note is for something used in the source of this
5529 reload insn, or in the output address, move the note. */
5532 rtx next_reg_notes = XEXP (reg_notes, 1);
5533 if (REG_NOTE_KIND (reg_notes) == REG_DEAD
5534 && GET_CODE (XEXP (reg_notes, 0)) == REG
5535 && ((GET_CODE (dest) != REG
5536 && reg_overlap_mentioned_for_reload_p (XEXP (reg_notes, 0),
5538 || reg_overlap_mentioned_for_reload_p (XEXP (reg_notes, 0),
5541 *prev_reg_note = next_reg_notes;
5542 XEXP (reg_notes, 1) = REG_NOTES (insn1);
5543 REG_NOTES (insn1) = reg_notes;
5546 prev_reg_note = &XEXP (reg_notes, 1);
5548 reg_notes = next_reg_notes;
5554 /* For all the spill regs newly reloaded in this instruction,
5555 record what they were reloaded from, so subsequent instructions
5556 can inherit the reloads.
5558 Update spill_reg_store for the reloads of this insn.
5559 Copy the elements that were updated in the loop above. */
5561 for (j = 0; j < n_reloads; j++)
5563 register int r = reload_order[j];
5564 register int i = reload_spill_index[r];
5566 /* I is nonneg if this reload used one of the spill regs.
5567 If reload_reg_rtx[r] is 0, this is an optional reload
5568 that we opted to ignore. */
5570 if (i >= 0 && reload_reg_rtx[r] != 0)
5572 /* First, clear out memory of what used to be in this spill reg.
5573 If consecutive registers are used, clear them all. */
5575 = HARD_REGNO_NREGS (spill_regs[i], GET_MODE (reload_reg_rtx[r]));
5578 for (k = 0; k < nr; k++)
5580 reg_reloaded_contents[spill_reg_order[spill_regs[i] + k]] = -1;
5581 reg_reloaded_insn[spill_reg_order[spill_regs[i] + k]] = 0;
5584 /* Maybe the spill reg contains a copy of reload_out. */
5585 if (reload_out[r] != 0 && GET_CODE (reload_out[r]) == REG)
5587 register int nregno = REGNO (reload_out[r]);
5589 spill_reg_store[i] = new_spill_reg_store[i];
5590 reg_last_reload_reg[nregno] = reload_reg_rtx[r];
5592 for (k = 0; k < nr; k++)
5594 reg_reloaded_contents[spill_reg_order[spill_regs[i] + k]]
5596 reg_reloaded_insn[spill_reg_order[spill_regs[i] + k]] = insn;
5600 /* Maybe the spill reg contains a copy of reload_in. */
5601 else if (reload_out[r] == 0
5602 && reload_in[r] != 0
5603 && (GET_CODE (reload_in[r]) == REG
5604 || GET_CODE (reload_in_reg[r]) == REG))
5606 register int nregno;
5607 if (GET_CODE (reload_in[r]) == REG)
5608 nregno = REGNO (reload_in[r]);
5610 nregno = REGNO (reload_in_reg[r]);
5612 /* If there are two separate reloads (one in and one out)
5613 for the same (hard or pseudo) reg,
5614 leave reg_last_reload_reg set
5615 based on the output reload.
5616 Otherwise, set it from this input reload. */
5617 if (!reg_has_output_reload[nregno]
5618 /* But don't do so if another input reload
5619 will clobber this one's value. */
5620 && reload_reg_reaches_end_p (spill_regs[i],
5621 reload_when_needed[r]))
5623 reg_last_reload_reg[nregno] = reload_reg_rtx[r];
5625 /* Unless we inherited this reload, show we haven't
5626 recently done a store. */
5627 if (! reload_inherited[r])
5628 spill_reg_store[i] = 0;
5630 for (k = 0; k < nr; k++)
5632 reg_reloaded_contents[spill_reg_order[spill_regs[i] + k]]
5634 reg_reloaded_insn[spill_reg_order[spill_regs[i] + k]]
5641 /* The following if-statement was #if 0'd in 1.34 (or before...).
5642 It's reenabled in 1.35 because supposedly nothing else
5643 deals with this problem. */
5645 /* If a register gets output-reloaded from a non-spill register,
5646 that invalidates any previous reloaded copy of it.
5647 But forget_old_reloads_1 won't get to see it, because
5648 it thinks only about the original insn. So invalidate it here. */
5649 if (i < 0 && reload_out[r] != 0 && GET_CODE (reload_out[r]) == REG)
5651 register int nregno = REGNO (reload_out[r]);
5652 reg_last_reload_reg[nregno] = 0;
5657 /* Emit code before BEFORE_INSN to perform an input reload of IN to RELOADREG.
5658 Returns first insn emitted. */
5661 gen_input_reload (reloadreg, in, before_insn)
5666 register rtx prev_insn = PREV_INSN (before_insn);
5668 /* How to do this reload can get quite tricky. Normally, we are being
5669 asked to reload a simple operand, such as a MEM, a constant, or a pseudo
5670 register that didn't get a hard register. In that case we can just
5671 call emit_move_insn.
5673 We can also be asked to reload a PLUS that adds either two registers or
5674 a register and a constant or MEM. This can occur during frame pointer
5675 elimination. That case if handled by trying to emit a single insn
5676 to perform the add. If it is not valid, we use a two insn sequence.
5678 Finally, we could be called to handle an 'o' constraint by putting
5679 an address into a register. In that case, we first try to do this
5680 with a named pattern of "reload_load_address". If no such pattern
5681 exists, we just emit a SET insn and hope for the best (it will normally
5682 be valid on machines that use 'o').
5684 This entire process is made complex because reload will never
5685 process the insns we generate here and so we must ensure that
5686 they will fit their constraints and also by the fact that parts of
5687 IN might be being reloaded separately and replaced with spill registers.
5688 Because of this, we are, in some sense, just guessing the right approach
5689 here. The one listed above seems to work.
5691 ??? At some point, this whole thing needs to be rethought. */
5693 if (GET_CODE (in) == PLUS
5694 && GET_CODE (XEXP (in, 0)) == REG
5695 && (GET_CODE (XEXP (in, 1)) == REG
5696 || CONSTANT_P (XEXP (in, 1))
5697 || GET_CODE (XEXP (in, 1)) == MEM))
5699 /* We need to compute the sum of what is either a register and a
5700 constant, a register and memory, or a hard register and a pseudo
5701 register and put it into the reload register. The best possible way
5702 of doing this is if the machine has a three-operand ADD insn that
5703 accepts the required operands.
5705 The simplest approach is to try to generate such an insn and see if it
5706 is recognized and matches its constraints. If so, it can be used.
5708 It might be better not to actually emit the insn unless it is valid,
5709 but we need to pass the insn as an operand to `recog' and
5710 `insn_extract' and it is simpler to emit and then delete the insn if
5711 not valid than to dummy things up. */
5713 rtx op0, op1, tem, insn;
5716 op0 = find_replacement (&XEXP (in, 0));
5717 op1 = find_replacement (&XEXP (in, 1));
5719 /* Since constraint checking is strict, commutativity won't be
5720 checked, so we need to do that here to avoid spurious failure
5721 if the add instruction is two-address and the second operand
5722 of the add is the same as the reload reg, which is frequently
5723 the case. If the insn would be A = B + A, rearrange it so
5724 it will be A = A + B as constrain_operands expects. */
5726 if (GET_CODE (XEXP (in, 1)) == REG
5727 && REGNO (reloadreg) == REGNO (XEXP (in, 1)))
5728 tem = op0, op0 = op1, op1 = tem;
5730 if (op0 != XEXP (in, 0) || op1 != XEXP (in, 1))
5731 in = gen_rtx (PLUS, GET_MODE (in), op0, op1);
5733 insn = emit_insn_before (gen_rtx (SET, VOIDmode, reloadreg, in),
5735 code = recog_memoized (insn);
5739 insn_extract (insn);
5740 /* We want constrain operands to treat this insn strictly in
5741 its validity determination, i.e., the way it would after reload
5743 if (constrain_operands (code, 1))
5747 if (PREV_INSN (insn))
5748 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
5749 if (NEXT_INSN (insn))
5750 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
5752 /* If that failed, we must use a conservative two-insn sequence.
5753 use move to copy constant, MEM, or pseudo register to the reload
5754 register since "move" will be able to handle an arbitrary operand,
5755 unlike add which can't, in general. Then add the registers.
5757 If there is another way to do this for a specific machine, a
5758 DEFINE_PEEPHOLE should be specified that recognizes the sequence
5761 if (CONSTANT_P (op1) || GET_CODE (op1) == MEM
5762 || (GET_CODE (op1) == REG
5763 && REGNO (op1) >= FIRST_PSEUDO_REGISTER))
5764 tem = op0, op0 = op1, op1 = tem;
5766 emit_insn_before (gen_move_insn (reloadreg, op0), before_insn);
5768 /* If OP0 and OP1 are the same, we can use RELOADREG for OP1.
5769 This fixes a problem on the 32K where the stack pointer cannot
5770 be used as an operand of an add insn. */
5772 if (rtx_equal_p (op0, op1))
5775 emit_insn_before (gen_add2_insn (reloadreg, op1), before_insn);
5778 #ifdef SECONDARY_MEMORY_NEEDED
5779 /* If we need a memory location to do the move, do it that way. */
5780 else if (GET_CODE (in) == REG && REGNO (in) < FIRST_PSEUDO_REGISTER
5781 && SECONDARY_MEMORY_NEEDED (REGNO_REG_CLASS (REGNO (in)),
5782 REGNO_REG_CLASS (REGNO (reloadreg)),
5783 GET_MODE (reloadreg)))
5785 /* Get the memory to use and rewrite both registers to its mode. */
5786 rtx loc = get_secondary_mem (in, GET_MODE (reloadreg));
5788 if (GET_MODE (loc) != GET_MODE (reloadreg))
5789 reloadreg = gen_rtx (REG, GET_MODE (loc), REGNO (reloadreg));
5791 if (GET_MODE (loc) != GET_MODE (in))
5792 in = gen_rtx (REG, GET_MODE (loc), REGNO (in));
5794 emit_insn_before (gen_move_insn (loc, in), before_insn);
5795 emit_insn_before (gen_move_insn (reloadreg, loc), before_insn);
5799 /* If IN is a simple operand, use gen_move_insn. */
5800 else if (GET_RTX_CLASS (GET_CODE (in)) == 'o' || GET_CODE (in) == SUBREG)
5801 emit_insn_before (gen_move_insn (reloadreg, in), before_insn);
5803 #ifdef HAVE_reload_load_address
5804 else if (HAVE_reload_load_address)
5805 emit_insn_before (gen_reload_load_address (reloadreg, in), before_insn);
5808 /* Otherwise, just write (set REGLOADREG IN) and hope for the best. */
5810 emit_insn_before (gen_rtx (SET, VOIDmode, reloadreg, in), before_insn);
5812 /* Return the first insn emitted.
5813 We can not just return PREV_INSN (before_insn), because there may have
5814 been multiple instructions emitted. Also note that gen_move_insn may
5815 emit more than one insn itself, so we can not assume that there is one
5816 insn emitted per emit_insn_before call. */
5818 return NEXT_INSN (prev_insn);
5821 /* Delete a previously made output-reload
5822 whose result we now believe is not needed.
5823 First we double-check.
5825 INSN is the insn now being processed.
5826 OUTPUT_RELOAD_INSN is the insn of the output reload.
5827 J is the reload-number for this insn. */
5830 delete_output_reload (insn, j, output_reload_insn)
5833 rtx output_reload_insn;
5837 /* Get the raw pseudo-register referred to. */
5839 rtx reg = reload_in[j];
5840 while (GET_CODE (reg) == SUBREG)
5841 reg = SUBREG_REG (reg);
5843 /* If the pseudo-reg we are reloading is no longer referenced
5844 anywhere between the store into it and here,
5845 and no jumps or labels intervene, then the value can get
5846 here through the reload reg alone.
5847 Otherwise, give up--return. */
5848 for (i1 = NEXT_INSN (output_reload_insn);
5849 i1 != insn; i1 = NEXT_INSN (i1))
5851 if (GET_CODE (i1) == CODE_LABEL || GET_CODE (i1) == JUMP_INSN)
5853 if ((GET_CODE (i1) == INSN || GET_CODE (i1) == CALL_INSN)
5854 && reg_mentioned_p (reg, PATTERN (i1)))
5858 /* If this insn will store in the pseudo again,
5859 the previous store can be removed. */
5860 if (reload_out[j] == reload_in[j])
5861 delete_insn (output_reload_insn);
5863 /* See if the pseudo reg has been completely replaced
5864 with reload regs. If so, delete the store insn
5865 and forget we had a stack slot for the pseudo. */
5866 else if (reg_n_deaths[REGNO (reg)] == 1
5867 && reg_basic_block[REGNO (reg)] >= 0
5868 && find_regno_note (insn, REG_DEAD, REGNO (reg)))
5872 /* We know that it was used only between here
5873 and the beginning of the current basic block.
5874 (We also know that the last use before INSN was
5875 the output reload we are thinking of deleting, but never mind that.)
5876 Search that range; see if any ref remains. */
5877 for (i2 = PREV_INSN (insn); i2; i2 = PREV_INSN (i2))
5879 rtx set = single_set (i2);
5881 /* Uses which just store in the pseudo don't count,
5882 since if they are the only uses, they are dead. */
5883 if (set != 0 && SET_DEST (set) == reg)
5885 if (GET_CODE (i2) == CODE_LABEL
5886 || GET_CODE (i2) == JUMP_INSN)
5888 if ((GET_CODE (i2) == INSN || GET_CODE (i2) == CALL_INSN)
5889 && reg_mentioned_p (reg, PATTERN (i2)))
5890 /* Some other ref remains;
5891 we can't do anything. */
5895 /* Delete the now-dead stores into this pseudo. */
5896 for (i2 = PREV_INSN (insn); i2; i2 = PREV_INSN (i2))
5898 rtx set = single_set (i2);
5900 if (set != 0 && SET_DEST (set) == reg)
5902 if (GET_CODE (i2) == CODE_LABEL
5903 || GET_CODE (i2) == JUMP_INSN)
5907 /* For the debugging info,
5908 say the pseudo lives in this reload reg. */
5909 reg_renumber[REGNO (reg)] = REGNO (reload_reg_rtx[j]);
5910 alter_reg (REGNO (reg), -1);
5915 /* Output reload-insns to reload VALUE into RELOADREG.
5916 VALUE is an autoincrement or autodecrement RTX whose operand
5917 is a register or memory location;
5918 so reloading involves incrementing that location.
5920 INC_AMOUNT is the number to increment or decrement by (always positive).
5921 This cannot be deduced from VALUE.
5923 INSN is the insn before which the new insns should be emitted.
5925 The return value is the first of the insns emitted. */
5928 inc_for_reload (reloadreg, value, inc_amount, insn)
5934 /* REG or MEM to be copied and incremented. */
5935 rtx incloc = XEXP (value, 0);
5936 /* Nonzero if increment after copying. */
5937 int post = (GET_CODE (value) == POST_DEC || GET_CODE (value) == POST_INC);
5938 rtx prev = PREV_INSN (insn);
5943 /* No hard register is equivalent to this register after
5944 inc/dec operation. If REG_LAST_RELOAD_REG were non-zero,
5945 we could inc/dec that register as well (maybe even using it for
5946 the source), but I'm not sure it's worth worrying about. */
5947 if (GET_CODE (incloc) == REG)
5948 reg_last_reload_reg[REGNO (incloc)] = 0;
5950 if (GET_CODE (value) == PRE_DEC || GET_CODE (value) == POST_DEC)
5951 inc_amount = - inc_amount;
5953 inc = GEN_INT (inc_amount);
5955 /* If this is post-increment, first copy the location to the reload reg. */
5957 emit_insn_before (gen_move_insn (reloadreg, incloc), insn);
5959 /* See if we can directly increment INCLOC. Use a method similar to that
5960 in gen_input_reload. */
5962 add_insn = emit_insn_before (gen_rtx (SET, VOIDmode, incloc,
5963 gen_rtx (PLUS, GET_MODE (incloc),
5964 incloc, inc)), insn);
5966 code = recog_memoized (add_insn);
5969 insn_extract (add_insn);
5970 if (constrain_operands (code, 1))
5972 /* If this is a pre-increment and we have incremented the value
5973 where it lives, copy the incremented value to RELOADREG to
5974 be used as an address. */
5977 emit_insn_before (gen_move_insn (reloadreg, incloc), insn);
5978 return NEXT_INSN (prev);
5982 if (PREV_INSN (add_insn))
5983 NEXT_INSN (PREV_INSN (add_insn)) = NEXT_INSN (add_insn);
5984 if (NEXT_INSN (add_insn))
5985 PREV_INSN (NEXT_INSN (add_insn)) = PREV_INSN (add_insn);
5987 /* If couldn't do the increment directly, must increment in RELOADREG.
5988 The way we do this depends on whether this is pre- or post-increment.
5989 For pre-increment, copy INCLOC to the reload register, increment it
5990 there, then save back. */
5994 emit_insn_before (gen_move_insn (reloadreg, incloc), insn);
5995 emit_insn_before (gen_add2_insn (reloadreg, inc), insn);
5996 emit_insn_before (gen_move_insn (incloc, reloadreg), insn);
6001 Because this might be a jump insn or a compare, and because RELOADREG
6002 may not be available after the insn in an input reload, we must do
6003 the incrementation before the insn being reloaded for.
6005 We have already copied INCLOC to RELOADREG. Increment the copy in
6006 RELOADREG, save that back, then decrement RELOADREG so it has
6007 the original value. */
6009 emit_insn_before (gen_add2_insn (reloadreg, inc), insn);
6010 emit_insn_before (gen_move_insn (incloc, reloadreg), insn);
6011 emit_insn_before (gen_add2_insn (reloadreg, GEN_INT (-inc_amount)),
6015 return NEXT_INSN (prev);
6018 /* Return 1 if we are certain that the constraint-string STRING allows
6019 the hard register REG. Return 0 if we can't be sure of this. */
6022 constraint_accepts_reg_p (string, reg)
6027 int regno = true_regnum (reg);
6030 /* Initialize for first alternative. */
6032 /* Check that each alternative contains `g' or `r'. */
6034 switch (c = *string++)
6037 /* If an alternative lacks `g' or `r', we lose. */
6040 /* If an alternative lacks `g' or `r', we lose. */
6043 /* Initialize for next alternative. */
6048 /* Any general reg wins for this alternative. */
6049 if (TEST_HARD_REG_BIT (reg_class_contents[(int) GENERAL_REGS], regno))
6053 /* Any reg in specified class wins for this alternative. */
6055 enum reg_class class = REG_CLASS_FROM_LETTER (c);
6057 if (TEST_HARD_REG_BIT (reg_class_contents[(int) class], regno))
6063 /* Return the number of places FIND appears within X, but don't count
6064 an occurrence if some SET_DEST is FIND. */
6067 count_occurrences (x, find)
6068 register rtx x, find;
6071 register enum rtx_code code;
6072 register char *format_ptr;
6080 code = GET_CODE (x);
6095 if (SET_DEST (x) == find)
6096 return count_occurrences (SET_SRC (x), find);
6100 format_ptr = GET_RTX_FORMAT (code);
6103 for (i = 0; i < GET_RTX_LENGTH (code); i++)
6105 switch (*format_ptr++)
6108 count += count_occurrences (XEXP (x, i), find);
6112 if (XVEC (x, i) != NULL)
6114 for (j = 0; j < XVECLEN (x, i); j++)
6115 count += count_occurrences (XVECEXP (x, i, j), find);
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