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. */
24 #include "insn-config.h"
25 #include "insn-flags.h"
26 #include "insn-codes.h"
30 #include "hard-reg-set.h"
33 #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 static 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 elmination.
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 extern int xmalloc ();
252 /* List of labels that must never be deleted. */
253 extern rtx forced_labels;
255 /* This structure is used to record information about register eliminations.
256 Each array entry describes one possible way of eliminating a register
257 in favor of another. If there is more than one way of eliminating a
258 particular register, the most preferred should be specified first. */
260 static struct elim_table
262 int from; /* Register number to be eliminated. */
263 int to; /* Register number used as replacement. */
264 int initial_offset; /* Initial difference between values. */
265 int can_eliminate; /* Non-zero if this elimination can be done. */
266 int can_eliminate_previous; /* Value of CAN_ELIMINATE in previous scan over
267 insns made by reload. */
268 int offset; /* Current offset between the two regs. */
269 int max_offset; /* Maximum offset between the two regs. */
270 int previous_offset; /* Offset at end of previous insn. */
271 int ref_outside_mem; /* "to" has been referenced outside a MEM. */
272 rtx from_rtx; /* REG rtx for the register to be eliminated.
273 We cannot simply compare the number since
274 we might then spuriously replace a hard
275 register corresponding to a pseudo
276 assigned to the reg to be eliminated. */
277 rtx to_rtx; /* REG rtx for the replacement. */
280 /* If a set of eliminable registers was specified, define the table from it.
281 Otherwise, default to the normal case of the frame pointer being
282 replaced by the stack pointer. */
284 #ifdef ELIMINABLE_REGS
287 {{ FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM}};
290 #define NUM_ELIMINABLE_REGS (sizeof reg_eliminate / sizeof reg_eliminate[0])
292 /* Record the number of pending eliminations that have an offset not equal
293 to their initial offset. If non-zero, we use a new copy of each
294 replacement result in any insns encountered. */
295 static int num_not_at_initial_offset;
297 /* Count the number of registers that we may be able to eliminate. */
298 static int num_eliminable;
300 /* For each label, we record the offset of each elimination. If we reach
301 a label by more than one path and an offset differs, we cannot do the
302 elimination. This information is indexed by the number of the label.
303 The first table is an array of flags that records whether we have yet
304 encountered a label and the second table is an array of arrays, one
305 entry in the latter array for each elimination. */
307 static char *offsets_known_at;
308 static int (*offsets_at)[NUM_ELIMINABLE_REGS];
310 /* Number of labels in the current function. */
312 static int num_labels;
314 void mark_home_live ();
315 static void count_possible_groups ();
316 static int possible_group_p ();
317 static void scan_paradoxical_subregs ();
318 static void reload_as_needed ();
319 static int modes_equiv_for_class_p ();
320 static void alter_reg ();
321 static void delete_dead_insn ();
322 static int new_spill_reg();
323 static void set_label_offsets ();
324 static int eliminate_regs_in_insn ();
325 static void mark_not_eliminable ();
326 static int spill_hard_reg ();
327 static void choose_reload_regs ();
328 static void emit_reload_insns ();
329 static void delete_output_reload ();
330 static void forget_old_reloads_1 ();
331 static void order_regs_for_reload ();
332 static rtx inc_for_reload ();
333 static int constraint_accepts_reg_p ();
334 static int count_occurrences ();
336 extern void remove_death ();
337 extern rtx adj_offsettable_operand ();
338 extern rtx form_sum ();
345 /* Often (MEM (REG n)) is still valid even if (REG n) is put on the stack.
346 Set spill_indirect_levels to the number of levels such addressing is
347 permitted, zero if it is not permitted at all. */
350 = gen_rtx (MEM, Pmode,
351 gen_rtx (PLUS, Pmode,
352 gen_rtx (REG, Pmode, LAST_VIRTUAL_REGISTER + 1),
353 gen_rtx (CONST_INT, VOIDmode, 4)));
354 spill_indirect_levels = 0;
356 while (memory_address_p (QImode, tem))
358 spill_indirect_levels++;
359 tem = gen_rtx (MEM, Pmode, tem);
362 /* See if indirect addressing is valid for (MEM (SYMBOL_REF ...)). */
364 tem = gen_rtx (MEM, Pmode, gen_rtx (SYMBOL_REF, Pmode, "foo"));
365 indirect_symref_ok = memory_address_p (QImode, tem);
367 /* See if reg+reg is a valid (and offsettable) address. */
369 tem = gen_rtx (PLUS, Pmode,
370 gen_rtx (REG, Pmode, FRAME_POINTER_REGNUM),
371 gen_rtx (REG, Pmode, FRAME_POINTER_REGNUM));
372 /* This way, we make sure that reg+reg is an offsettable address. */
373 tem = plus_constant (tem, 4);
375 double_reg_address_ok = memory_address_p (QImode, tem);
377 /* Initialize obstack for our rtl allocation. */
378 gcc_obstack_init (&reload_obstack);
379 reload_firstobj = (char *) obstack_alloc (&reload_obstack, 0);
381 #ifdef HAVE_SECONDARY_RELOADS
383 /* Initialize the optabs for doing special input and output reloads. */
385 for (i = 0; i < NUM_MACHINE_MODES; i++)
386 reload_in_optab[i] = reload_out_optab[i] = CODE_FOR_nothing;
388 #ifdef HAVE_reload_inqi
389 if (HAVE_reload_inqi)
390 reload_in_optab[(int) QImode] = CODE_FOR_reload_inqi;
392 #ifdef HAVE_reload_inhi
393 if (HAVE_reload_inhi)
394 reload_in_optab[(int) HImode] = CODE_FOR_reload_inhi;
396 #ifdef HAVE_reload_insi
397 if (HAVE_reload_insi)
398 reload_in_optab[(int) SImode] = CODE_FOR_reload_insi;
400 #ifdef HAVE_reload_indi
401 if (HAVE_reload_indi)
402 reload_in_optab[(int) DImode] = CODE_FOR_reload_indi;
404 #ifdef HAVE_reload_inti
405 if (HAVE_reload_inti)
406 reload_in_optab[(int) TImode] = CODE_FOR_reload_inti;
408 #ifdef HAVE_reload_insf
409 if (HAVE_reload_insf)
410 reload_in_optab[(int) SFmode] = CODE_FOR_reload_insf;
412 #ifdef HAVE_reload_indf
413 if (HAVE_reload_indf)
414 reload_in_optab[(int) DFmode] = CODE_FOR_reload_indf;
416 #ifdef HAVE_reload_inxf
417 if (HAVE_reload_inxf)
418 reload_in_optab[(int) XFmode] = CODE_FOR_reload_inxf;
420 #ifdef HAVE_reload_intf
421 if (HAVE_reload_intf)
422 reload_in_optab[(int) TFmode] = CODE_FOR_reload_intf;
425 #ifdef HAVE_reload_outqi
426 if (HAVE_reload_outqi)
427 reload_out_optab[(int) QImode] = CODE_FOR_reload_outqi;
429 #ifdef HAVE_reload_outhi
430 if (HAVE_reload_outhi)
431 reload_out_optab[(int) HImode] = CODE_FOR_reload_outhi;
433 #ifdef HAVE_reload_outsi
434 if (HAVE_reload_outsi)
435 reload_out_optab[(int) SImode] = CODE_FOR_reload_outsi;
437 #ifdef HAVE_reload_outdi
438 if (HAVE_reload_outdi)
439 reload_out_optab[(int) DImode] = CODE_FOR_reload_outdi;
441 #ifdef HAVE_reload_outti
442 if (HAVE_reload_outti)
443 reload_out_optab[(int) TImode] = CODE_FOR_reload_outti;
445 #ifdef HAVE_reload_outsf
446 if (HAVE_reload_outsf)
447 reload_out_optab[(int) SFmode] = CODE_FOR_reload_outsf;
449 #ifdef HAVE_reload_outdf
450 if (HAVE_reload_outdf)
451 reload_out_optab[(int) DFmode] = CODE_FOR_reload_outdf;
453 #ifdef HAVE_reload_outxf
454 if (HAVE_reload_outxf)
455 reload_out_optab[(int) XFmode] = CODE_FOR_reload_outxf;
457 #ifdef HAVE_reload_outtf
458 if (HAVE_reload_outtf)
459 reload_out_optab[(int) TFmode] = CODE_FOR_reload_outtf;
462 #endif /* HAVE_SECONDARY_RELOADS */
466 /* Main entry point for the reload pass, and only entry point
469 FIRST is the first insn of the function being compiled.
471 GLOBAL nonzero means we were called from global_alloc
472 and should attempt to reallocate any pseudoregs that we
473 displace from hard regs we will use for reloads.
474 If GLOBAL is zero, we do not have enough information to do that,
475 so any pseudo reg that is spilled must go to the stack.
477 DUMPFILE is the global-reg debugging dump file stream, or 0.
478 If it is nonzero, messages are written to it to describe
479 which registers are seized as reload regs, which pseudo regs
480 are spilled from them, and where the pseudo regs are reallocated to. */
483 reload (first, global, dumpfile)
491 register struct elim_table *ep;
493 int something_changed;
494 int something_needs_reloads;
495 int something_needs_elimination;
496 int new_basic_block_needs;
497 enum reg_class caller_save_spill_class = NO_REGS;
498 int caller_save_group_size = 1;
500 /* The basic block number currently being processed for INSN. */
503 /* Make sure even insns with volatile mem refs are recognizable. */
506 /* Enable find_equiv_reg to distinguish insns made by reload. */
507 reload_first_uid = get_max_uid ();
509 for (i = 0; i < N_REG_CLASSES; i++)
510 basic_block_needs[i] = 0;
512 /* Remember which hard regs appear explicitly
513 before we merge into `regs_ever_live' the ones in which
514 pseudo regs have been allocated. */
515 bcopy (regs_ever_live, regs_explicitly_used, sizeof regs_ever_live);
517 /* We don't have a stack slot for any spill reg yet. */
518 bzero (spill_stack_slot, sizeof spill_stack_slot);
519 bzero (spill_stack_slot_width, sizeof spill_stack_slot_width);
521 /* Initialize the save area information for caller-save, in case some
525 /* Compute which hard registers are now in use
526 as homes for pseudo registers.
527 This is done here rather than (eg) in global_alloc
528 because this point is reached even if not optimizing. */
530 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
533 /* Make sure that the last insn in the chain
534 is not something that needs reloading. */
535 emit_note (0, NOTE_INSN_DELETED);
537 /* Find all the pseudo registers that didn't get hard regs
538 but do have known equivalent constants or memory slots.
539 These include parameters (known equivalent to parameter slots)
540 and cse'd or loop-moved constant memory addresses.
542 Record constant equivalents in reg_equiv_constant
543 so they will be substituted by find_reloads.
544 Record memory equivalents in reg_mem_equiv so they can
545 be substituted eventually by altering the REG-rtx's. */
547 reg_equiv_constant = (rtx *) alloca (max_regno * sizeof (rtx));
548 bzero (reg_equiv_constant, max_regno * sizeof (rtx));
549 reg_equiv_memory_loc = (rtx *) alloca (max_regno * sizeof (rtx));
550 bzero (reg_equiv_memory_loc, max_regno * sizeof (rtx));
551 reg_equiv_mem = (rtx *) alloca (max_regno * sizeof (rtx));
552 bzero (reg_equiv_mem, max_regno * sizeof (rtx));
553 reg_equiv_init = (rtx *) alloca (max_regno * sizeof (rtx));
554 bzero (reg_equiv_init, max_regno * sizeof (rtx));
555 reg_equiv_address = (rtx *) alloca (max_regno * sizeof (rtx));
556 bzero (reg_equiv_address, max_regno * sizeof (rtx));
557 reg_max_ref_width = (int *) alloca (max_regno * sizeof (int));
558 bzero (reg_max_ref_width, max_regno * sizeof (int));
560 /* Look for REG_EQUIV notes; record what each pseudo is equivalent to.
561 Also find all paradoxical subregs
562 and find largest such for each pseudo. */
564 for (insn = first; insn; insn = NEXT_INSN (insn))
566 rtx set = single_set (insn);
568 if (set != 0 && GET_CODE (SET_DEST (set)) == REG)
570 rtx note = find_reg_note (insn, REG_EQUIV, 0);
572 #ifdef LEGITIMATE_PIC_OPERAND_P
573 && (! CONSTANT_P (XEXP (note, 0)) || ! flag_pic
574 || LEGITIMATE_PIC_OPERAND_P (XEXP (note, 0)))
578 rtx x = XEXP (note, 0);
579 i = REGNO (SET_DEST (set));
580 if (i > LAST_VIRTUAL_REGISTER)
582 if (GET_CODE (x) == MEM)
583 reg_equiv_memory_loc[i] = x;
584 else if (CONSTANT_P (x))
586 if (LEGITIMATE_CONSTANT_P (x))
587 reg_equiv_constant[i] = x;
589 reg_equiv_memory_loc[i]
590 = force_const_mem (GET_MODE (SET_DEST (set)), x);
595 /* If this register is being made equivalent to a MEM
596 and the MEM is not SET_SRC, the equivalencing insn
597 is one with the MEM as a SET_DEST and it occurs later.
598 So don't mark this insn now. */
599 if (GET_CODE (x) != MEM
600 || rtx_equal_p (SET_SRC (set), x))
601 reg_equiv_init[i] = insn;
606 /* If this insn is setting a MEM from a register equivalent to it,
607 this is the equivalencing insn. */
608 else if (set && GET_CODE (SET_DEST (set)) == MEM
609 && GET_CODE (SET_SRC (set)) == REG
610 && reg_equiv_memory_loc[REGNO (SET_SRC (set))]
611 && rtx_equal_p (SET_DEST (set),
612 reg_equiv_memory_loc[REGNO (SET_SRC (set))]))
613 reg_equiv_init[REGNO (SET_SRC (set))] = insn;
615 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
616 scan_paradoxical_subregs (PATTERN (insn));
619 /* Does this function require a frame pointer? */
621 frame_pointer_needed = (! flag_omit_frame_pointer
622 #ifdef EXIT_IGNORE_STACK
623 /* ?? If EXIT_IGNORE_STACK is set, we will not save
624 and restore sp for alloca. So we can't eliminate
625 the frame pointer in that case. At some point,
626 we should improve this by emitting the
627 sp-adjusting insns for this case. */
628 || (current_function_calls_alloca
629 && EXIT_IGNORE_STACK)
631 || FRAME_POINTER_REQUIRED);
635 /* Initialize the table of registers to eliminate. The way we do this
636 depends on how the eliminable registers were defined. */
637 #ifdef ELIMINABLE_REGS
638 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
640 ep->can_eliminate = ep->can_eliminate_previous
641 = (CAN_ELIMINATE (ep->from, ep->to)
642 && (ep->from != FRAME_POINTER_REGNUM || ! frame_pointer_needed));
645 reg_eliminate[0].can_eliminate = reg_eliminate[0].can_eliminate_previous
646 = ! frame_pointer_needed;
649 /* Count the number of eliminable registers and build the FROM and TO
650 REG rtx's. Note that code in gen_rtx will cause, e.g.,
651 gen_rtx (REG, Pmode, STACK_POINTER_REGNUM) to equal stack_pointer_rtx.
652 We depend on this. */
653 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
655 num_eliminable += ep->can_eliminate;
656 ep->from_rtx = gen_rtx (REG, Pmode, ep->from);
657 ep->to_rtx = gen_rtx (REG, Pmode, ep->to);
660 num_labels = max_label_num () - get_first_label_num ();
662 /* Allocate the tables used to store offset information at labels. */
663 offsets_known_at = (char *) alloca (num_labels);
665 = (int (*)[NUM_ELIMINABLE_REGS])
666 alloca (num_labels * NUM_ELIMINABLE_REGS * sizeof (int));
668 offsets_known_at -= get_first_label_num ();
669 offsets_at -= get_first_label_num ();
671 /* Alter each pseudo-reg rtx to contain its hard reg number.
672 Assign stack slots to the pseudos that lack hard regs or equivalents.
673 Do not touch virtual registers. */
675 for (i = LAST_VIRTUAL_REGISTER + 1; i < max_regno; i++)
678 /* Round size of stack frame to BIGGEST_ALIGNMENT. This must be done here
679 because the stack size may be a part of the offset computation for
680 register elimination. */
681 assign_stack_local (BLKmode, 0, 0);
683 /* If we have some registers we think can be eliminated, scan all insns to
684 see if there is an insn that sets one of these registers to something
685 other than itself plus a constant. If so, the register cannot be
686 eliminated. Doing this scan here eliminates an extra pass through the
687 main reload loop in the most common case where register elimination
689 for (insn = first; insn && num_eliminable; insn = NEXT_INSN (insn))
690 if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN
691 || GET_CODE (insn) == CALL_INSN)
692 note_stores (PATTERN (insn), mark_not_eliminable);
694 #ifndef REGISTER_CONSTRAINTS
695 /* If all the pseudo regs have hard regs,
696 except for those that are never referenced,
697 we know that no reloads are needed. */
698 /* But that is not true if there are register constraints, since
699 in that case some pseudos might be in the wrong kind of hard reg. */
701 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
702 if (reg_renumber[i] == -1 && reg_n_refs[i] != 0)
705 if (i == max_regno && num_eliminable == 0 && ! caller_save_needed)
709 /* Compute the order of preference for hard registers to spill.
710 Store them by decreasing preference in potential_reload_regs. */
712 order_regs_for_reload ();
714 /* So far, no hard regs have been spilled. */
716 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
717 spill_reg_order[i] = -1;
719 /* On most machines, we can't use any register explicitly used in the
720 rtl as a spill register. But on some, we have to. Those will have
721 taken care to keep the life of hard regs as short as possible. */
723 #ifdef SMALL_REGISTER_CLASSES
724 CLEAR_HARD_REG_SET (forbidden_regs);
726 COPY_HARD_REG_SET (forbidden_regs, bad_spill_regs);
729 /* Spill any hard regs that we know we can't eliminate. */
730 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
731 if (! ep->can_eliminate)
733 spill_hard_reg (ep->from, global, dumpfile, 1);
734 regs_ever_live[ep->from] = 1;
738 for (i = 0; i < N_REG_CLASSES; i++)
740 basic_block_needs[i] = (char *)alloca (n_basic_blocks);
741 bzero (basic_block_needs[i], n_basic_blocks);
744 /* This loop scans the entire function each go-round
745 and repeats until one repetition spills no additional hard regs. */
747 /* This flag is set when a psuedo reg is spilled,
748 to require another pass. Note that getting an additional reload
749 reg does not necessarily imply any pseudo reg was spilled;
750 sometimes we find a reload reg that no pseudo reg was allocated in. */
751 something_changed = 1;
752 /* This flag is set if there are any insns that require reloading. */
753 something_needs_reloads = 0;
754 /* This flag is set if there are any insns that require register
756 something_needs_elimination = 0;
757 while (something_changed)
761 /* For each class, number of reload regs needed in that class.
762 This is the maximum over all insns of the needs in that class
763 of the individual insn. */
764 int max_needs[N_REG_CLASSES];
765 /* For each class, size of group of consecutive regs
766 that is needed for the reloads of this class. */
767 int group_size[N_REG_CLASSES];
768 /* For each class, max number of consecutive groups needed.
769 (Each group contains group_size[CLASS] consecutive registers.) */
770 int max_groups[N_REG_CLASSES];
771 /* For each class, max number needed of regs that don't belong
772 to any of the groups. */
773 int max_nongroups[N_REG_CLASSES];
774 /* For each class, the machine mode which requires consecutive
775 groups of regs of that class.
776 If two different modes ever require groups of one class,
777 they must be the same size and equally restrictive for that class,
778 otherwise we can't handle the complexity. */
779 enum machine_mode group_mode[N_REG_CLASSES];
782 something_changed = 0;
783 bzero (max_needs, sizeof max_needs);
784 bzero (max_groups, sizeof max_groups);
785 bzero (max_nongroups, sizeof max_nongroups);
786 bzero (group_size, sizeof group_size);
787 for (i = 0; i < N_REG_CLASSES; i++)
788 group_mode[i] = VOIDmode;
790 /* Keep track of which basic blocks are needing the reloads. */
793 /* Remember whether any element of basic_block_needs
794 changes from 0 to 1 in this pass. */
795 new_basic_block_needs = 0;
797 /* Reset all offsets on eliminable registers to their initial values. */
798 #ifdef ELIMINABLE_REGS
799 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
801 INITIAL_ELIMINATION_OFFSET (ep->from, ep->to, ep->initial_offset);
802 ep->previous_offset = ep->offset
803 = ep->max_offset = ep->initial_offset;
806 #ifdef INITIAL_FRAME_POINTER_OFFSET
807 INITIAL_FRAME_POINTER_OFFSET (reg_eliminate[0].initial_offset);
809 if (!FRAME_POINTER_REQUIRED)
811 reg_eliminate[0].initial_offset = 0;
813 reg_eliminate[0].previous_offset = reg_eliminate[0].max_offset
814 = reg_eliminate[0].offset = reg_eliminate[0].initial_offset;
817 num_not_at_initial_offset = 0;
819 bzero (&offsets_known_at[get_first_label_num ()], num_labels);
821 /* Set a known offset for each forced label to be at the initial offset
822 of each elimination. We do this because we assume that all
823 computed jumps occur from a location where each elimination is
824 at its initial offset. */
826 for (x = forced_labels; x; x = XEXP (x, 1))
828 set_label_offsets (XEXP (x, 0), 0, 1);
830 /* For each pseudo register that has an equivalent location defined,
831 try to eliminate any eliminable registers (such as the frame pointer)
832 assuming initial offsets for the replacement register, which
835 If the resulting location is directly addressable, substitute
836 the MEM we just got directly for the old REG.
838 If it is not addressable but is a constant or the sum of a hard reg
839 and constant, it is probably not addressable because the constant is
840 out of range, in that case record the address; we will generate
841 hairy code to compute the address in a register each time it is
844 If the location is not addressable, but does not have one of the
845 above forms, assign a stack slot. We have to do this to avoid the
846 potential of producing lots of reloads if, e.g., a location involves
847 a pseudo that didn't get a hard register and has an equivalent memory
848 location that also involves a pseudo that didn't get a hard register.
850 Perhaps at some point we will improve reload_when_needed handling
851 so this problem goes away. But that's very hairy. */
853 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
854 if (reg_renumber[i] < 0 && reg_equiv_memory_loc[i])
856 rtx x = eliminate_regs (reg_equiv_memory_loc[i], 0, 0);
858 if (strict_memory_address_p (GET_MODE (regno_reg_rtx[i]),
860 reg_equiv_mem[i] = x, reg_equiv_address[i] = 0;
861 else if (CONSTANT_P (XEXP (x, 0))
862 || (GET_CODE (XEXP (x, 0)) == PLUS
863 && GET_CODE (XEXP (XEXP (x, 0), 0)) == REG
864 && (REGNO (XEXP (XEXP (x, 0), 0))
865 < FIRST_PSEUDO_REGISTER)
866 && CONSTANT_P (XEXP (XEXP (x, 0), 1))))
867 reg_equiv_address[i] = XEXP (x, 0), reg_equiv_mem[i] = 0;
870 /* Make a new stack slot. Then indicate that something
871 changed so we go back and recompute offsets for
872 eliminable registers because the allocation of memory
873 below might change some offset. reg_equiv_{mem,address}
874 will be set up for this pseudo on the next pass around
876 reg_equiv_memory_loc[i] = 0;
877 reg_equiv_init[i] = 0;
879 something_changed = 1;
883 /* If we allocated another psuedo to the stack, redo elimination
885 if (something_changed)
888 /* If caller-saves needs a group, initialize the group to include
889 the size and mode required for caller-saves. */
891 if (caller_save_group_size > 1)
893 group_mode[(int) caller_save_spill_class] = Pmode;
894 group_size[(int) caller_save_spill_class] = caller_save_group_size;
897 /* Compute the most additional registers needed by any instruction.
898 Collect information separately for each class of regs. */
900 for (insn = first; insn; insn = NEXT_INSN (insn))
902 if (global && this_block + 1 < n_basic_blocks
903 && insn == basic_block_head[this_block+1])
906 /* If this is a label, a JUMP_INSN, or has REG_NOTES (which
907 might include REG_LABEL), we need to see what effects this
908 has on the known offsets at labels. */
910 if (GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == JUMP_INSN
911 || (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
912 && REG_NOTES (insn) != 0))
913 set_label_offsets (insn, insn, 0);
915 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
917 /* Nonzero means don't use a reload reg that overlaps
918 the place where a function value can be returned. */
919 rtx avoid_return_reg = 0;
921 rtx old_body = PATTERN (insn);
922 int old_code = INSN_CODE (insn);
923 rtx old_notes = REG_NOTES (insn);
924 int did_elimination = 0;
926 /* Initially, count RELOAD_OTHER reloads.
927 Later, merge in the other kinds. */
928 int insn_needs[N_REG_CLASSES];
929 int insn_groups[N_REG_CLASSES];
930 int insn_total_groups = 0;
932 /* Count RELOAD_FOR_INPUT_RELOAD_ADDRESS reloads. */
933 int insn_needs_for_inputs[N_REG_CLASSES];
934 int insn_groups_for_inputs[N_REG_CLASSES];
935 int insn_total_groups_for_inputs = 0;
937 /* Count RELOAD_FOR_OUTPUT_RELOAD_ADDRESS reloads. */
938 int insn_needs_for_outputs[N_REG_CLASSES];
939 int insn_groups_for_outputs[N_REG_CLASSES];
940 int insn_total_groups_for_outputs = 0;
942 /* Count RELOAD_FOR_OPERAND_ADDRESS reloads. */
943 int insn_needs_for_operands[N_REG_CLASSES];
944 int insn_groups_for_operands[N_REG_CLASSES];
945 int insn_total_groups_for_operands = 0;
947 #if 0 /* This wouldn't work nowadays, since optimize_bit_field
948 looks for non-strict memory addresses. */
949 /* Optimization: a bit-field instruction whose field
950 happens to be a byte or halfword in memory
951 can be changed to a move instruction. */
953 if (GET_CODE (PATTERN (insn)) == SET)
955 rtx dest = SET_DEST (PATTERN (insn));
956 rtx src = SET_SRC (PATTERN (insn));
958 if (GET_CODE (dest) == ZERO_EXTRACT
959 || GET_CODE (dest) == SIGN_EXTRACT)
960 optimize_bit_field (PATTERN (insn), insn, reg_equiv_mem);
961 if (GET_CODE (src) == ZERO_EXTRACT
962 || GET_CODE (src) == SIGN_EXTRACT)
963 optimize_bit_field (PATTERN (insn), insn, reg_equiv_mem);
967 /* If needed, eliminate any eliminable registers. */
969 did_elimination = eliminate_regs_in_insn (insn, 0);
971 #ifdef SMALL_REGISTER_CLASSES
972 /* Set avoid_return_reg if this is an insn
973 that might use the value of a function call. */
974 if (GET_CODE (insn) == CALL_INSN)
976 if (GET_CODE (PATTERN (insn)) == SET)
977 after_call = SET_DEST (PATTERN (insn));
978 else if (GET_CODE (PATTERN (insn)) == PARALLEL
979 && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET)
980 after_call = SET_DEST (XVECEXP (PATTERN (insn), 0, 0));
984 else if (after_call != 0
985 && !(GET_CODE (PATTERN (insn)) == SET
986 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx))
988 if (reg_mentioned_p (after_call, PATTERN (insn)))
989 avoid_return_reg = after_call;
992 #endif /* SMALL_REGISTER_CLASSES */
994 /* Analyze the instruction. */
995 find_reloads (insn, 0, spill_indirect_levels, global,
998 /* Remember for later shortcuts which insns had any reloads or
999 register eliminations.
1001 One might think that it would be worthwhile to mark insns
1002 that need register replacements but not reloads, but this is
1003 not safe because find_reloads may do some manipulation of
1004 the insn (such as swapping commutative operands), which would
1005 be lost when we restore the old pattern after register
1006 replacement. So the actions of find_reloads must be redone in
1007 subsequent passes or in reload_as_needed.
1009 However, it is safe to mark insns that need reloads
1010 but not register replacement. */
1012 PUT_MODE (insn, (did_elimination ? QImode
1013 : n_reloads ? HImode
1016 /* Discard any register replacements done. */
1017 if (did_elimination)
1019 obstack_free (&reload_obstack, reload_firstobj);
1020 PATTERN (insn) = old_body;
1021 INSN_CODE (insn) = old_code;
1022 REG_NOTES (insn) = old_notes;
1023 something_needs_elimination = 1;
1026 /* If this insn has no reloads, we need not do anything except
1027 in the case of a CALL_INSN when we have caller-saves and
1028 caller-save needs reloads. */
1031 && ! (GET_CODE (insn) == CALL_INSN
1032 && caller_save_spill_class != NO_REGS))
1035 something_needs_reloads = 1;
1037 for (i = 0; i < N_REG_CLASSES; i++)
1039 insn_needs[i] = 0, insn_groups[i] = 0;
1040 insn_needs_for_inputs[i] = 0, insn_groups_for_inputs[i] = 0;
1041 insn_needs_for_outputs[i] = 0, insn_groups_for_outputs[i] = 0;
1042 insn_needs_for_operands[i] = 0, insn_groups_for_operands[i] = 0;
1045 /* Count each reload once in every class
1046 containing the reload's own class. */
1048 for (i = 0; i < n_reloads; i++)
1050 register enum reg_class *p;
1052 enum machine_mode mode;
1055 int *this_total_groups;
1057 /* Don't count the dummy reloads, for which one of the
1058 regs mentioned in the insn can be used for reloading.
1059 Don't count optional reloads.
1060 Don't count reloads that got combined with others. */
1061 if (reload_reg_rtx[i] != 0
1062 || reload_optional[i] != 0
1063 || (reload_out[i] == 0 && reload_in[i] == 0
1064 && ! reload_secondary_p[i]))
1067 /* Decide which time-of-use to count this reload for. */
1068 switch (reload_when_needed[i])
1071 case RELOAD_FOR_OUTPUT:
1072 case RELOAD_FOR_INPUT:
1073 this_needs = insn_needs;
1074 this_groups = insn_groups;
1075 this_total_groups = &insn_total_groups;
1078 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
1079 this_needs = insn_needs_for_inputs;
1080 this_groups = insn_groups_for_inputs;
1081 this_total_groups = &insn_total_groups_for_inputs;
1084 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
1085 this_needs = insn_needs_for_outputs;
1086 this_groups = insn_groups_for_outputs;
1087 this_total_groups = &insn_total_groups_for_outputs;
1090 case RELOAD_FOR_OPERAND_ADDRESS:
1091 this_needs = insn_needs_for_operands;
1092 this_groups = insn_groups_for_operands;
1093 this_total_groups = &insn_total_groups_for_operands;
1097 mode = reload_inmode[i];
1098 if (GET_MODE_SIZE (reload_outmode[i]) > GET_MODE_SIZE (mode))
1099 mode = reload_outmode[i];
1100 size = CLASS_MAX_NREGS (reload_reg_class[i], mode);
1103 enum machine_mode other_mode, allocate_mode;
1105 /* Count number of groups needed separately from
1106 number of individual regs needed. */
1107 this_groups[(int) reload_reg_class[i]]++;
1108 p = reg_class_superclasses[(int) reload_reg_class[i]];
1109 while (*p != LIM_REG_CLASSES)
1110 this_groups[(int) *p++]++;
1111 (*this_total_groups)++;
1113 /* Record size and mode of a group of this class. */
1114 /* If more than one size group is needed,
1115 make all groups the largest needed size. */
1116 if (group_size[(int) reload_reg_class[i]] < size)
1118 other_mode = group_mode[(int) reload_reg_class[i]];
1119 allocate_mode = mode;
1121 group_size[(int) reload_reg_class[i]] = size;
1122 group_mode[(int) reload_reg_class[i]] = mode;
1127 allocate_mode = group_mode[(int) reload_reg_class[i]];
1130 /* Crash if two dissimilar machine modes both need
1131 groups of consecutive regs of the same class. */
1133 if (other_mode != VOIDmode
1134 && other_mode != allocate_mode
1135 && ! modes_equiv_for_class_p (allocate_mode,
1137 reload_reg_class[i]))
1142 this_needs[(int) reload_reg_class[i]] += 1;
1143 p = reg_class_superclasses[(int) reload_reg_class[i]];
1144 while (*p != LIM_REG_CLASSES)
1145 this_needs[(int) *p++] += 1;
1151 /* All reloads have been counted for this insn;
1152 now merge the various times of use.
1153 This sets insn_needs, etc., to the maximum total number
1154 of registers needed at any point in this insn. */
1156 for (i = 0; i < N_REG_CLASSES; i++)
1159 this_max = insn_needs_for_inputs[i];
1160 if (insn_needs_for_outputs[i] > this_max)
1161 this_max = insn_needs_for_outputs[i];
1162 if (insn_needs_for_operands[i] > this_max)
1163 this_max = insn_needs_for_operands[i];
1164 insn_needs[i] += this_max;
1165 this_max = insn_groups_for_inputs[i];
1166 if (insn_groups_for_outputs[i] > this_max)
1167 this_max = insn_groups_for_outputs[i];
1168 if (insn_groups_for_operands[i] > this_max)
1169 this_max = insn_groups_for_operands[i];
1170 insn_groups[i] += this_max;
1173 insn_total_groups += MAX (insn_total_groups_for_inputs,
1174 MAX (insn_total_groups_for_outputs,
1175 insn_total_groups_for_operands));
1177 /* If this is a CALL_INSN and caller-saves will need
1178 a spill register, act as if the spill register is
1179 needed for this insn. However, the spill register
1180 can be used by any reload of this insn, so we only
1181 need do something if no need for that class has
1184 The assumption that every CALL_INSN will trigger a
1185 caller-save is highly conservative, however, the number
1186 of cases where caller-saves will need a spill register but
1187 a block containing a CALL_INSN won't need a spill register
1188 of that class should be quite rare.
1190 If a group is needed, the size and mode of the group will
1191 have been set up at the begining of this loop. */
1193 if (GET_CODE (insn) == CALL_INSN
1194 && caller_save_spill_class != NO_REGS)
1196 int *caller_save_needs
1197 = (caller_save_group_size > 1 ? insn_groups : insn_needs);
1199 if (caller_save_needs[(int) caller_save_spill_class] == 0)
1201 register enum reg_class *p
1202 = reg_class_superclasses[(int) caller_save_spill_class];
1204 caller_save_needs[(int) caller_save_spill_class]++;
1206 while (*p != LIM_REG_CLASSES)
1207 caller_save_needs[(int) *p++] += 1;
1210 if (caller_save_group_size > 1)
1211 insn_total_groups = MAX (insn_total_groups, 1);
1214 /* Update the basic block needs. */
1216 for (i = 0; i < N_REG_CLASSES; i++)
1217 if (global && (insn_needs[i] || insn_groups[i])
1218 && ! basic_block_needs[i][this_block])
1220 new_basic_block_needs = 1;
1221 basic_block_needs[i][this_block] = 1;
1224 #ifdef SMALL_REGISTER_CLASSES
1225 /* If this insn stores the value of a function call,
1226 and that value is in a register that has been spilled,
1227 and if the insn needs a reload in a class
1228 that might use that register as the reload register,
1229 then add add an extra need in that class.
1230 This makes sure we have a register available that does
1231 not overlap the return value. */
1232 if (avoid_return_reg)
1234 int regno = REGNO (avoid_return_reg);
1236 = HARD_REGNO_NREGS (regno, GET_MODE (avoid_return_reg));
1239 for (r = regno; r < regno + nregs; r++)
1240 if (spill_reg_order[r] >= 0)
1241 for (i = 0; i < N_REG_CLASSES; i++)
1242 if (TEST_HARD_REG_BIT (reg_class_contents[i], r))
1244 if (insn_needs[i] > 0)
1246 if (insn_groups[i] > 0
1253 #endif /* SMALL_REGISTER_CLASSES */
1255 /* For each class, collect maximum need of any insn. */
1257 for (i = 0; i < N_REG_CLASSES; i++)
1259 if (max_needs[i] < insn_needs[i])
1260 max_needs[i] = insn_needs[i];
1261 if (max_groups[i] < insn_groups[i])
1262 max_groups[i] = insn_groups[i];
1263 if (insn_total_groups > 0)
1264 if (max_nongroups[i] < insn_needs[i])
1265 max_nongroups[i] = insn_needs[i];
1268 /* Note that there is a continue statement above. */
1271 /* If we have caller-saves, set up the save areas and see if caller-save
1272 will need a spill register. */
1274 if (caller_save_needed
1275 && ! setup_save_areas (&something_changed)
1276 && caller_save_spill_class == NO_REGS)
1278 /* The class we will need depends on whether the machine
1279 supports the sum of two registers for an address; see
1280 find_address_reloads for details. */
1282 caller_save_spill_class
1283 = double_reg_address_ok ? INDEX_REG_CLASS : BASE_REG_CLASS;
1284 caller_save_group_size
1285 = CLASS_MAX_NREGS (caller_save_spill_class, Pmode);
1286 something_changed = 1;
1289 /* Now deduct from the needs for the registers already
1290 available (already spilled). */
1292 CLEAR_HARD_REG_SET (counted_for_groups);
1293 CLEAR_HARD_REG_SET (counted_for_nongroups);
1295 /* First find all regs alone in their class
1296 and count them (if desired) for non-groups.
1297 We would be screwed if a group took the only reg in a class
1298 for which a non-group reload is needed.
1299 (Note there is still a bug; if a class has 2 regs,
1300 both could be stolen by groups and we would lose the same way.
1301 With luck, no machine will need a nongroup in a 2-reg class.) */
1303 for (i = 0; i < n_spills; i++)
1305 register enum reg_class *p;
1306 class = (int) REGNO_REG_CLASS (spill_regs[i]);
1308 if (reg_class_size[class] == 1 && max_nongroups[class] > 0)
1311 p = reg_class_superclasses[class];
1312 while (*p != LIM_REG_CLASSES)
1313 max_needs[(int) *p++]--;
1315 SET_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]);
1316 max_nongroups[class]--;
1317 p = reg_class_superclasses[class];
1318 while (*p != LIM_REG_CLASSES)
1320 if (max_nongroups[(int) *p] > 0)
1321 SET_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]);
1322 max_nongroups[(int) *p++]--;
1327 /* Now find all consecutive groups of spilled registers
1328 and mark each group off against the need for such groups.
1329 But don't count them against ordinary need, yet. */
1331 count_possible_groups (group_size, group_mode, max_groups);
1333 /* Now count all spill regs against the individual need,
1334 This includes those counted above for groups,
1335 but not those previously counted for nongroups.
1337 Those that weren't counted_for_groups can also count against
1338 the not-in-group need. */
1340 for (i = 0; i < n_spills; i++)
1342 register enum reg_class *p;
1343 class = (int) REGNO_REG_CLASS (spill_regs[i]);
1345 /* Those counted at the beginning shouldn't be counted twice. */
1346 if (! TEST_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]))
1349 p = reg_class_superclasses[class];
1350 while (*p != LIM_REG_CLASSES)
1351 max_needs[(int) *p++]--;
1353 if (! TEST_HARD_REG_BIT (counted_for_groups, spill_regs[i]))
1355 if (max_nongroups[class] > 0)
1356 SET_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]);
1357 max_nongroups[class]--;
1358 p = reg_class_superclasses[class];
1359 while (*p != LIM_REG_CLASSES)
1361 if (max_nongroups[(int) *p] > 0)
1362 SET_HARD_REG_BIT (counted_for_nongroups,
1364 max_nongroups[(int) *p++]--;
1370 /* Look for the case where we have discovered that we can't replace
1371 register A with register B and that means that we will now be
1372 trying to replace register A with register C. This means we can
1373 no longer replace register C with register B and we need to disable
1374 such an elimination, if it exists. This occurs often with A == ap,
1375 B == sp, and C == fp. */
1377 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
1379 struct elim_table *op;
1380 register int new_to = -1;
1382 if (! ep->can_eliminate && ep->can_eliminate_previous)
1384 /* Find the current elimination for ep->from, if there is a
1386 for (op = reg_eliminate;
1387 op < ®_eliminate[NUM_ELIMINABLE_REGS]; op++)
1388 if (op->from == ep->from && op->can_eliminate)
1394 /* See if there is an elimination of NEW_TO -> EP->TO. If so,
1396 for (op = reg_eliminate;
1397 op < ®_eliminate[NUM_ELIMINABLE_REGS]; op++)
1398 if (op->from == new_to && op->to == ep->to)
1399 op->can_eliminate = 0;
1403 /* See if any registers that we thought we could eliminate the previous
1404 time are no longer eliminable. If so, something has changed and we
1405 must spill the register. Also, recompute the number of eliminable
1406 registers and see if the frame pointer is needed; it is if there is
1407 no elimination of the frame pointer that we can perform. */
1409 frame_pointer_needed = 1;
1410 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
1412 if (ep->can_eliminate && ep->from == FRAME_POINTER_REGNUM)
1413 frame_pointer_needed = 0;
1415 if (! ep->can_eliminate && ep->can_eliminate_previous)
1417 ep->can_eliminate_previous = 0;
1418 spill_hard_reg (ep->from, global, dumpfile, 1);
1419 regs_ever_live[ep->from] = 1;
1420 something_changed = 1;
1425 /* If all needs are met, we win. */
1427 for (i = 0; i < N_REG_CLASSES; i++)
1428 if (max_needs[i] > 0 || max_groups[i] > 0 || max_nongroups[i] > 0)
1430 if (i == N_REG_CLASSES && !new_basic_block_needs && ! something_changed)
1433 /* Not all needs are met; must spill more hard regs. */
1435 /* If any element of basic_block_needs changed from 0 to 1,
1436 re-spill all the regs already spilled. This may spill
1437 additional pseudos that didn't spill before. */
1439 if (new_basic_block_needs)
1440 for (i = 0; i < n_spills; i++)
1442 |= spill_hard_reg (spill_regs[i], global, dumpfile, 0);
1444 /* Now find more reload regs to satisfy the remaining need
1445 Do it by ascending class number, since otherwise a reg
1446 might be spilled for a big class and might fail to count
1447 for a smaller class even though it belongs to that class.
1449 Count spilled regs in `spills', and add entries to
1450 `spill_regs' and `spill_reg_order'.
1452 ??? Note there is a problem here.
1453 When there is a need for a group in a high-numbered class,
1454 and also need for non-group regs that come from a lower class,
1455 the non-group regs are chosen first. If there aren't many regs,
1456 they might leave no room for a group.
1458 This was happening on the 386. To fix it, we added the code
1459 that calls possible_group_p, so that the lower class won't
1460 break up the last possible group.
1462 Really fixing the problem would require changes above
1463 in counting the regs already spilled, and in choose_reload_regs.
1464 It might be hard to avoid introducing bugs there. */
1466 for (class = 0; class < N_REG_CLASSES; class++)
1468 /* First get the groups of registers.
1469 If we got single registers first, we might fragment
1471 while (max_groups[class] > 0)
1473 /* If any single spilled regs happen to form groups,
1474 count them now. Maybe we don't really need
1475 to spill another group. */
1476 count_possible_groups (group_size, group_mode, max_groups);
1478 /* Groups of size 2 (the only groups used on most machines)
1479 are treated specially. */
1480 if (group_size[class] == 2)
1482 /* First, look for a register that will complete a group. */
1483 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1485 int j = potential_reload_regs[i];
1487 if (j >= 0 && ! TEST_HARD_REG_BIT (bad_spill_regs, j)
1489 ((j > 0 && (other = j - 1, spill_reg_order[other] >= 0)
1490 && TEST_HARD_REG_BIT (reg_class_contents[class], j)
1491 && TEST_HARD_REG_BIT (reg_class_contents[class], other)
1492 && HARD_REGNO_MODE_OK (other, group_mode[class])
1493 && ! TEST_HARD_REG_BIT (counted_for_nongroups,
1495 /* We don't want one part of another group.
1496 We could get "two groups" that overlap! */
1497 && ! TEST_HARD_REG_BIT (counted_for_groups, other))
1499 (j < FIRST_PSEUDO_REGISTER - 1
1500 && (other = j + 1, spill_reg_order[other] >= 0)
1501 && TEST_HARD_REG_BIT (reg_class_contents[class], j)
1502 && TEST_HARD_REG_BIT (reg_class_contents[class], other)
1503 && HARD_REGNO_MODE_OK (j, group_mode[class])
1504 && ! TEST_HARD_REG_BIT (counted_for_nongroups,
1506 && ! TEST_HARD_REG_BIT (counted_for_groups,
1509 register enum reg_class *p;
1511 /* We have found one that will complete a group,
1512 so count off one group as provided. */
1513 max_groups[class]--;
1514 p = reg_class_superclasses[class];
1515 while (*p != LIM_REG_CLASSES)
1516 max_groups[(int) *p++]--;
1518 /* Indicate both these regs are part of a group. */
1519 SET_HARD_REG_BIT (counted_for_groups, j);
1520 SET_HARD_REG_BIT (counted_for_groups, other);
1524 /* We can't complete a group, so start one. */
1525 if (i == FIRST_PSEUDO_REGISTER)
1526 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1528 int j = potential_reload_regs[i];
1529 if (j >= 0 && j + 1 < FIRST_PSEUDO_REGISTER
1530 && spill_reg_order[j] < 0 && spill_reg_order[j + 1] < 0
1531 && TEST_HARD_REG_BIT (reg_class_contents[class], j)
1532 && TEST_HARD_REG_BIT (reg_class_contents[class], j + 1)
1533 && HARD_REGNO_MODE_OK (j, group_mode[class])
1534 && ! TEST_HARD_REG_BIT (counted_for_nongroups,
1539 /* I should be the index in potential_reload_regs
1540 of the new reload reg we have found. */
1543 |= new_spill_reg (i, class, max_needs, 0,
1548 /* For groups of more than 2 registers,
1549 look for a sufficient sequence of unspilled registers,
1550 and spill them all at once. */
1551 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1553 int j = potential_reload_regs[i];
1555 if (j >= 0 && j + 1 < FIRST_PSEUDO_REGISTER
1556 && HARD_REGNO_MODE_OK (j, group_mode[class]))
1558 /* Check each reg in the sequence. */
1559 for (k = 0; k < group_size[class]; k++)
1560 if (! (spill_reg_order[j + k] < 0
1561 && ! TEST_HARD_REG_BIT (bad_spill_regs, j + k)
1562 && TEST_HARD_REG_BIT (reg_class_contents[class], j + k)))
1564 /* We got a full sequence, so spill them all. */
1565 if (k == group_size[class])
1567 register enum reg_class *p;
1568 for (k = 0; k < group_size[class]; k++)
1571 SET_HARD_REG_BIT (counted_for_groups, j + k);
1572 for (idx = 0; idx < FIRST_PSEUDO_REGISTER; idx++)
1573 if (potential_reload_regs[idx] == j + k)
1576 |= new_spill_reg (idx, class, max_needs, 0,
1580 /* We have found one that will complete a group,
1581 so count off one group as provided. */
1582 max_groups[class]--;
1583 p = reg_class_superclasses[class];
1584 while (*p != LIM_REG_CLASSES)
1585 max_groups[(int) *p++]--;
1594 /* Now similarly satisfy all need for single registers. */
1596 while (max_needs[class] > 0 || max_nongroups[class] > 0)
1598 /* Consider the potential reload regs that aren't
1599 yet in use as reload regs, in order of preference.
1600 Find the most preferred one that's in this class. */
1602 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1603 if (potential_reload_regs[i] >= 0
1604 && TEST_HARD_REG_BIT (reg_class_contents[class],
1605 potential_reload_regs[i])
1606 /* If this reg will not be available for groups,
1607 pick one that does not foreclose possible groups.
1608 This is a kludge, and not very general,
1609 but it should be sufficient to make the 386 work,
1610 and the problem should not occur on machines with
1612 && (max_nongroups[class] == 0
1613 || possible_group_p (potential_reload_regs[i], max_groups)))
1616 /* I should be the index in potential_reload_regs
1617 of the new reload reg we have found. */
1620 |= new_spill_reg (i, class, max_needs, max_nongroups,
1626 /* If global-alloc was run, notify it of any register eliminations we have
1629 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
1630 if (ep->can_eliminate)
1631 mark_elimination (ep->from, ep->to);
1633 /* From now on, we need to emit any moves without making new pseudos. */
1634 reload_in_progress = 1;
1636 /* Insert code to save and restore call-clobbered hard regs
1637 around calls. Tell if what mode to use so that we will process
1638 those insns in reload_as_needed if we have to. */
1640 if (caller_save_needed)
1641 save_call_clobbered_regs (num_eliminable ? QImode
1642 : caller_save_spill_class != NO_REGS ? HImode
1645 /* If a pseudo has no hard reg, delete the insns that made the equivalence.
1646 If that insn didn't set the register (i.e., it copied the register to
1647 memory), just delete that insn instead of the equivalencing insn plus
1648 anything now dead. If we call delete_dead_insn on that insn, we may
1649 delete the insn that actually sets the register if the register die
1650 there and that is incorrect. */
1652 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
1653 if (reg_renumber[i] < 0 && reg_equiv_init[i] != 0
1654 && GET_CODE (reg_equiv_init[i]) != NOTE)
1656 if (reg_set_p (regno_reg_rtx[i], PATTERN (reg_equiv_init[i])))
1657 delete_dead_insn (reg_equiv_init[i]);
1660 PUT_CODE (reg_equiv_init[i], NOTE);
1661 NOTE_SOURCE_FILE (reg_equiv_init[i]) = 0;
1662 NOTE_LINE_NUMBER (reg_equiv_init[i]) = NOTE_INSN_DELETED;
1666 /* Use the reload registers where necessary
1667 by generating move instructions to move the must-be-register
1668 values into or out of the reload registers. */
1670 if (something_needs_reloads || something_needs_elimination
1671 || (caller_save_needed && num_eliminable)
1672 || caller_save_spill_class != NO_REGS)
1673 reload_as_needed (first, global);
1675 reload_in_progress = 0;
1677 /* Now eliminate all pseudo regs by modifying them into
1678 their equivalent memory references.
1679 The REG-rtx's for the pseudos are modified in place,
1680 so all insns that used to refer to them now refer to memory.
1682 For a reg that has a reg_equiv_address, all those insns
1683 were changed by reloading so that no insns refer to it any longer;
1684 but the DECL_RTL of a variable decl may refer to it,
1685 and if so this causes the debugging info to mention the variable. */
1687 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
1690 if (reg_equiv_mem[i])
1691 addr = XEXP (reg_equiv_mem[i], 0);
1692 if (reg_equiv_address[i])
1693 addr = reg_equiv_address[i];
1696 if (reg_renumber[i] < 0)
1698 rtx reg = regno_reg_rtx[i];
1699 XEXP (reg, 0) = addr;
1700 REG_USERVAR_P (reg) = 0;
1701 PUT_CODE (reg, MEM);
1703 else if (reg_equiv_mem[i])
1704 XEXP (reg_equiv_mem[i], 0) = addr;
1708 #ifdef PRESERVE_DEATH_INFO_REGNO_P
1709 /* Make a pass over all the insns and remove death notes for things that
1710 are no longer registers or no longer die in the insn (e.g., an input
1711 and output pseudo being tied). */
1713 for (insn = first; insn; insn = NEXT_INSN (insn))
1714 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
1718 for (note = REG_NOTES (insn); note; note = next)
1720 next = XEXP (note, 1);
1721 if (REG_NOTE_KIND (note) == REG_DEAD
1722 && (GET_CODE (XEXP (note, 0)) != REG
1723 || reg_set_p (XEXP (note, 0), PATTERN (insn))))
1724 remove_note (insn, note);
1729 /* Indicate that we no longer have known memory locations or constants. */
1730 reg_equiv_constant = 0;
1731 reg_equiv_memory_loc = 0;
1734 /* Nonzero if, after spilling reg REGNO for non-groups,
1735 it will still be possible to find a group if we still need one. */
1738 possible_group_p (regno, max_groups)
1743 int class = (int) NO_REGS;
1745 for (i = 0; i < (int) N_REG_CLASSES; i++)
1746 if (max_groups[i] > 0)
1752 if (class == (int) NO_REGS)
1755 /* Consider each pair of consecutive registers. */
1756 for (i = 0; i < FIRST_PSEUDO_REGISTER - 1; i++)
1758 /* Ignore pairs that include reg REGNO. */
1759 if (i == regno || i + 1 == regno)
1762 /* Ignore pairs that are outside the class that needs the group.
1763 ??? Here we fail to handle the case where two different classes
1764 independently need groups. But this never happens with our
1765 current machine descriptions. */
1766 if (! (TEST_HARD_REG_BIT (reg_class_contents[class], i)
1767 && TEST_HARD_REG_BIT (reg_class_contents[class], i + 1)))
1770 /* A pair of consecutive regs we can still spill does the trick. */
1771 if (spill_reg_order[i] < 0 && spill_reg_order[i + 1] < 0
1772 && ! TEST_HARD_REG_BIT (bad_spill_regs, i)
1773 && ! TEST_HARD_REG_BIT (bad_spill_regs, i + 1))
1776 /* A pair of one already spilled and one we can spill does it
1777 provided the one already spilled is not otherwise reserved. */
1778 if (spill_reg_order[i] < 0
1779 && ! TEST_HARD_REG_BIT (bad_spill_regs, i)
1780 && spill_reg_order[i + 1] >= 0
1781 && ! TEST_HARD_REG_BIT (counted_for_groups, i + 1)
1782 && ! TEST_HARD_REG_BIT (counted_for_nongroups, i + 1))
1784 if (spill_reg_order[i + 1] < 0
1785 && ! TEST_HARD_REG_BIT (bad_spill_regs, i + 1)
1786 && spill_reg_order[i] >= 0
1787 && ! TEST_HARD_REG_BIT (counted_for_groups, i)
1788 && ! TEST_HARD_REG_BIT (counted_for_nongroups, i))
1795 /* Count any groups that can be formed from the registers recently spilled.
1796 This is done class by class, in order of ascending class number. */
1799 count_possible_groups (group_size, group_mode, max_groups)
1800 int *group_size, *max_groups;
1801 enum machine_mode *group_mode;
1804 /* Now find all consecutive groups of spilled registers
1805 and mark each group off against the need for such groups.
1806 But don't count them against ordinary need, yet. */
1808 for (i = 0; i < N_REG_CLASSES; i++)
1809 if (group_size[i] > 1)
1811 char regmask[FIRST_PSEUDO_REGISTER];
1814 bzero (regmask, sizeof regmask);
1815 /* Make a mask of all the regs that are spill regs in class I. */
1816 for (j = 0; j < n_spills; j++)
1817 if (TEST_HARD_REG_BIT (reg_class_contents[i], spill_regs[j])
1818 && ! TEST_HARD_REG_BIT (counted_for_groups, spill_regs[j])
1819 && ! TEST_HARD_REG_BIT (counted_for_nongroups,
1821 regmask[spill_regs[j]] = 1;
1822 /* Find each consecutive group of them. */
1823 for (j = 0; j < FIRST_PSEUDO_REGISTER && max_groups[i] > 0; j++)
1824 if (regmask[j] && j + group_size[i] <= FIRST_PSEUDO_REGISTER
1825 /* Next line in case group-mode for this class
1826 demands an even-odd pair. */
1827 && HARD_REGNO_MODE_OK (j, group_mode[i]))
1830 for (k = 1; k < group_size[i]; k++)
1831 if (! regmask[j + k])
1833 if (k == group_size[i])
1835 /* We found a group. Mark it off against this class's
1836 need for groups, and against each superclass too. */
1837 register enum reg_class *p;
1839 p = reg_class_superclasses[i];
1840 while (*p != LIM_REG_CLASSES)
1841 max_groups[(int) *p++]--;
1842 /* Don't count these registers again. */
1843 for (k = 0; k < group_size[i]; k++)
1844 SET_HARD_REG_BIT (counted_for_groups, j + k);
1852 /* ALLOCATE_MODE is a register mode that needs to be reloaded. OTHER_MODE is
1853 another mode that needs to be reloaded for the same register class CLASS.
1854 If any reg in CLASS allows ALLOCATE_MODE but not OTHER_MODE, fail.
1855 ALLOCATE_MODE will never be smaller than OTHER_MODE.
1857 This code used to also fail if any reg in CLASS allows OTHER_MODE but not
1858 ALLOCATE_MODE. This test is unnecessary, because we will never try to put
1859 something of mode ALLOCATE_MODE into an OTHER_MODE register. Testing this
1860 causes unnecessary failures on machines requiring alignment of register
1861 groups when the two modes are different sizes, because the larger mode has
1862 more strict alignment rules than the smaller mode. */
1865 modes_equiv_for_class_p (allocate_mode, other_mode, class)
1866 enum machine_mode allocate_mode, other_mode;
1867 enum reg_class class;
1870 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
1872 if (TEST_HARD_REG_BIT (reg_class_contents[(int) class], regno)
1873 && HARD_REGNO_MODE_OK (regno, allocate_mode)
1874 && ! HARD_REGNO_MODE_OK (regno, other_mode))
1880 /* Add a new register to the tables of available spill-registers
1881 (as well as spilling all pseudos allocated to the register).
1882 I is the index of this register in potential_reload_regs.
1883 CLASS is the regclass whose need is being satisfied.
1884 MAX_NEEDS and MAX_NONGROUPS are the vectors of needs,
1885 so that this register can count off against them.
1886 MAX_NONGROUPS is 0 if this register is part of a group.
1887 GLOBAL and DUMPFILE are the same as the args that `reload' got. */
1890 new_spill_reg (i, class, max_needs, max_nongroups, global, dumpfile)
1898 register enum reg_class *p;
1900 int regno = potential_reload_regs[i];
1902 if (i >= FIRST_PSEUDO_REGISTER)
1903 abort (); /* Caller failed to find any register. */
1905 if (fixed_regs[regno] || TEST_HARD_REG_BIT (forbidden_regs, regno))
1906 fatal ("fixed or forbidden register was spilled.\n\
1907 This may be due to a compiler bug or to impossible asm statements.");
1909 /* Make reg REGNO an additional reload reg. */
1911 potential_reload_regs[i] = -1;
1912 spill_regs[n_spills] = regno;
1913 spill_reg_order[regno] = n_spills;
1915 fprintf (dumpfile, "Spilling reg %d.\n", spill_regs[n_spills]);
1917 /* Clear off the needs we just satisfied. */
1920 p = reg_class_superclasses[class];
1921 while (*p != LIM_REG_CLASSES)
1922 max_needs[(int) *p++]--;
1924 if (max_nongroups && max_nongroups[class] > 0)
1926 SET_HARD_REG_BIT (counted_for_nongroups, regno);
1927 max_nongroups[class]--;
1928 p = reg_class_superclasses[class];
1929 while (*p != LIM_REG_CLASSES)
1930 max_nongroups[(int) *p++]--;
1933 /* Spill every pseudo reg that was allocated to this reg
1934 or to something that overlaps this reg. */
1936 val = spill_hard_reg (spill_regs[n_spills], global, dumpfile, 0);
1938 /* If there are some registers still to eliminate and this register
1939 wasn't ever used before, additional stack space may have to be
1940 allocated to store this register. Thus, we may have changed the offset
1941 between the stack and frame pointers, so mark that something has changed.
1942 (If new pseudos were spilled, thus requiring more space, VAL would have
1943 been set non-zero by the call to spill_hard_reg above since additional
1944 reloads may be needed in that case.
1946 One might think that we need only set VAL to 1 if this is a call-used
1947 register. However, the set of registers that must be saved by the
1948 prologue is not identical to the call-used set. For example, the
1949 register used by the call insn for the return PC is a call-used register,
1950 but must be saved by the prologue. */
1951 if (num_eliminable && ! regs_ever_live[spill_regs[n_spills]])
1954 regs_ever_live[spill_regs[n_spills]] = 1;
1960 /* Delete an unneeded INSN and any previous insns who sole purpose is loading
1961 data that is dead in INSN. */
1964 delete_dead_insn (insn)
1967 rtx prev = prev_real_insn (insn);
1970 /* If the previous insn sets a register that dies in our insn, delete it
1972 if (prev && GET_CODE (PATTERN (prev)) == SET
1973 && (prev_dest = SET_DEST (PATTERN (prev)), GET_CODE (prev_dest) == REG)
1974 && reg_mentioned_p (prev_dest, PATTERN (insn))
1975 && find_regno_note (insn, REG_DEAD, REGNO (prev_dest)))
1976 delete_dead_insn (prev);
1978 PUT_CODE (insn, NOTE);
1979 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
1980 NOTE_SOURCE_FILE (insn) = 0;
1983 /* Modify the home of pseudo-reg I.
1984 The new home is present in reg_renumber[I].
1986 FROM_REG may be the hard reg that the pseudo-reg is being spilled from;
1987 or it may be -1, meaning there is none or it is not relevant.
1988 This is used so that all pseudos spilled from a given hard reg
1989 can share one stack slot. */
1992 alter_reg (i, from_reg)
1996 /* When outputting an inline function, this can happen
1997 for a reg that isn't actually used. */
1998 if (regno_reg_rtx[i] == 0)
2001 /* If the reg got changed to a MEM at rtl-generation time,
2003 if (GET_CODE (regno_reg_rtx[i]) != REG)
2006 /* Modify the reg-rtx to contain the new hard reg
2007 number or else to contain its pseudo reg number. */
2008 REGNO (regno_reg_rtx[i])
2009 = reg_renumber[i] >= 0 ? reg_renumber[i] : i;
2011 /* If we have a pseudo that is needed but has no hard reg or equivalent,
2012 allocate a stack slot for it. */
2014 if (reg_renumber[i] < 0
2015 && reg_n_refs[i] > 0
2016 && reg_equiv_constant[i] == 0
2017 && reg_equiv_memory_loc[i] == 0)
2020 int inherent_size = PSEUDO_REGNO_BYTES (i);
2021 int total_size = MAX (inherent_size, reg_max_ref_width[i]);
2024 /* Each pseudo reg has an inherent size which comes from its own mode,
2025 and a total size which provides room for paradoxical subregs
2026 which refer to the pseudo reg in wider modes.
2028 We can use a slot already allocated if it provides both
2029 enough inherent space and enough total space.
2030 Otherwise, we allocate a new slot, making sure that it has no less
2031 inherent space, and no less total space, then the previous slot. */
2034 /* No known place to spill from => no slot to reuse. */
2035 x = assign_stack_local (GET_MODE (regno_reg_rtx[i]), total_size, -1);
2036 #if BYTES_BIG_ENDIAN
2037 /* Cancel the big-endian correction done in assign_stack_local.
2038 Get the address of the beginning of the slot.
2039 This is so we can do a big-endian correction unconditionally
2041 adjust = inherent_size - total_size;
2044 /* Reuse a stack slot if possible. */
2045 else if (spill_stack_slot[from_reg] != 0
2046 && spill_stack_slot_width[from_reg] >= total_size
2047 && (GET_MODE_SIZE (GET_MODE (spill_stack_slot[from_reg]))
2049 x = spill_stack_slot[from_reg];
2050 /* Allocate a bigger slot. */
2053 /* Compute maximum size needed, both for inherent size
2054 and for total size. */
2055 enum machine_mode mode = GET_MODE (regno_reg_rtx[i]);
2056 if (spill_stack_slot[from_reg])
2058 if (GET_MODE_SIZE (GET_MODE (spill_stack_slot[from_reg]))
2060 mode = GET_MODE (spill_stack_slot[from_reg]);
2061 if (spill_stack_slot_width[from_reg] > total_size)
2062 total_size = spill_stack_slot_width[from_reg];
2064 /* Make a slot with that size. */
2065 x = assign_stack_local (mode, total_size, -1);
2066 #if BYTES_BIG_ENDIAN
2067 /* Cancel the big-endian correction done in assign_stack_local.
2068 Get the address of the beginning of the slot.
2069 This is so we can do a big-endian correction unconditionally
2071 adjust = GET_MODE_SIZE (mode) - total_size;
2073 spill_stack_slot[from_reg] = x;
2074 spill_stack_slot_width[from_reg] = total_size;
2077 #if BYTES_BIG_ENDIAN
2078 /* On a big endian machine, the "address" of the slot
2079 is the address of the low part that fits its inherent mode. */
2080 if (inherent_size < total_size)
2081 adjust += (total_size - inherent_size);
2082 #endif /* BYTES_BIG_ENDIAN */
2084 /* If we have any adjustment to make, or if the stack slot is the
2085 wrong mode, make a new stack slot. */
2086 if (adjust != 0 || GET_MODE (x) != GET_MODE (regno_reg_rtx[i]))
2088 x = gen_rtx (MEM, GET_MODE (regno_reg_rtx[i]),
2089 plus_constant (XEXP (x, 0), adjust));
2090 RTX_UNCHANGING_P (x) = RTX_UNCHANGING_P (regno_reg_rtx[i]);
2093 /* Save the stack slot for later. */
2094 reg_equiv_memory_loc[i] = x;
2098 /* Mark the slots in regs_ever_live for the hard regs
2099 used by pseudo-reg number REGNO. */
2102 mark_home_live (regno)
2105 register int i, lim;
2106 i = reg_renumber[regno];
2109 lim = i + HARD_REGNO_NREGS (i, PSEUDO_REGNO_MODE (regno));
2111 regs_ever_live[i++] = 1;
2114 /* This function handles the tracking of elimination offsets around branches.
2116 X is a piece of RTL being scanned.
2118 INSN is the insn that it came from, if any.
2120 INITIAL_P is non-zero if we are to set the offset to be the initial
2121 offset and zero if we are setting the offset of the label to be the
2125 set_label_offsets (x, insn, initial_p)
2130 enum rtx_code code = GET_CODE (x);
2133 struct elim_table *p;
2140 /* ... fall through ... */
2143 /* If we know nothing about this label, set the desired offsets. Note
2144 that this sets the offset at a label to be the offset before a label
2145 if we don't know anything about the label. This is not correct for
2146 the label after a BARRIER, but is the best guess we can make. If
2147 we guessed wrong, we will suppress an elimination that might have
2148 been possible had we been able to guess correctly. */
2150 if (! offsets_known_at[CODE_LABEL_NUMBER (x)])
2152 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
2153 offsets_at[CODE_LABEL_NUMBER (x)][i]
2154 = (initial_p ? reg_eliminate[i].initial_offset
2155 : reg_eliminate[i].offset);
2156 offsets_known_at[CODE_LABEL_NUMBER (x)] = 1;
2159 /* Otherwise, if this is the definition of a label and it is
2160 preceeded by a BARRIER, set our offsets to the known offset of
2164 && (tem = prev_nonnote_insn (insn)) != 0
2165 && GET_CODE (tem) == BARRIER)
2167 num_not_at_initial_offset = 0;
2168 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
2170 reg_eliminate[i].offset = reg_eliminate[i].previous_offset
2171 = offsets_at[CODE_LABEL_NUMBER (x)][i];
2172 if (reg_eliminate[i].offset != reg_eliminate[i].initial_offset)
2173 num_not_at_initial_offset++;
2178 /* If neither of the above cases is true, compare each offset
2179 with those previously recorded and suppress any eliminations
2180 where the offsets disagree. */
2182 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
2183 if (offsets_at[CODE_LABEL_NUMBER (x)][i]
2184 != (initial_p ? reg_eliminate[i].initial_offset
2185 : reg_eliminate[i].offset))
2186 reg_eliminate[i].can_eliminate = 0;
2191 set_label_offsets (PATTERN (insn), insn, initial_p);
2193 /* ... fall through ... */
2197 /* Any labels mentioned in REG_LABEL notes can be branched to indirectly
2198 and hence must have all eliminations at their initial offsets. */
2199 for (tem = REG_NOTES (x); tem; tem = XEXP (tem, 1))
2200 if (REG_NOTE_KIND (tem) == REG_LABEL)
2201 set_label_offsets (XEXP (tem, 0), insn, 1);
2206 /* Each of the labels in the address vector must be at their initial
2207 offsets. We want the first first for ADDR_VEC and the second
2208 field for ADDR_DIFF_VEC. */
2210 for (i = 0; i < XVECLEN (x, code == ADDR_DIFF_VEC); i++)
2211 set_label_offsets (XVECEXP (x, code == ADDR_DIFF_VEC, i),
2216 /* We only care about setting PC. If the source is not RETURN,
2217 IF_THEN_ELSE, or a label, disable any eliminations not at
2218 their initial offsets. Similarly if any arm of the IF_THEN_ELSE
2219 isn't one of those possibilities. For branches to a label,
2220 call ourselves recursively.
2222 Note that this can disable elimination unnecessarily when we have
2223 a non-local goto since it will look like a non-constant jump to
2224 someplace in the current function. This isn't a significant
2225 problem since such jumps will normally be when all elimination
2226 pairs are back to their initial offsets. */
2228 if (SET_DEST (x) != pc_rtx)
2231 switch (GET_CODE (SET_SRC (x)))
2238 set_label_offsets (XEXP (SET_SRC (x), 0), insn, initial_p);
2242 tem = XEXP (SET_SRC (x), 1);
2243 if (GET_CODE (tem) == LABEL_REF)
2244 set_label_offsets (XEXP (tem, 0), insn, initial_p);
2245 else if (GET_CODE (tem) != PC && GET_CODE (tem) != RETURN)
2248 tem = XEXP (SET_SRC (x), 2);
2249 if (GET_CODE (tem) == LABEL_REF)
2250 set_label_offsets (XEXP (tem, 0), insn, initial_p);
2251 else if (GET_CODE (tem) != PC && GET_CODE (tem) != RETURN)
2256 /* If we reach here, all eliminations must be at their initial
2257 offset because we are doing a jump to a variable address. */
2258 for (p = reg_eliminate; p < ®_eliminate[NUM_ELIMINABLE_REGS]; p++)
2259 if (p->offset != p->initial_offset)
2260 p->can_eliminate = 0;
2264 /* Used for communication between the next two function to properly share
2265 the vector for an ASM_OPERANDS. */
2267 static struct rtvec_def *old_asm_operands_vec, *new_asm_operands_vec;
2269 /* Scan X and replace any eliminable registers (such as fp) with a
2270 replacement (such as sp), plus an offset.
2272 MEM_MODE is the mode of an enclosing MEM. We need this to know how
2273 much to adjust a register for, e.g., PRE_DEC. Also, if we are inside a
2274 MEM, we are allowed to replace a sum of a register and the constant zero
2275 with the register, which we cannot do outside a MEM. In addition, we need
2276 to record the fact that a register is referenced outside a MEM.
2278 If INSN is nonzero, it is the insn containing X. If we replace a REG
2279 in a SET_DEST with an equivalent MEM and INSN is non-zero, write a
2280 CLOBBER of the pseudo after INSN so find_equiv_regs will know that
2281 that the REG is being modified.
2283 If we see a modification to a register we know about, take the
2284 appropriate action (see case SET, below).
2286 REG_EQUIV_MEM and REG_EQUIV_ADDRESS contain address that have had
2287 replacements done assuming all offsets are at their initial values. If
2288 they are not, or if REG_EQUIV_ADDRESS is nonzero for a pseudo we
2289 encounter, return the actual location so that find_reloads will do
2290 the proper thing. */
2293 eliminate_regs (x, mem_mode, insn)
2295 enum machine_mode mem_mode;
2298 enum rtx_code code = GET_CODE (x);
2299 struct elim_table *ep;
2324 /* First handle the case where we encounter a bare register that
2325 is eliminable. Replace it with a PLUS. */
2326 if (regno < FIRST_PSEUDO_REGISTER)
2328 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS];
2330 if (ep->from_rtx == x && ep->can_eliminate)
2333 ep->ref_outside_mem = 1;
2334 return plus_constant (ep->to_rtx, ep->previous_offset);
2338 else if (reg_equiv_memory_loc && reg_equiv_memory_loc[regno]
2339 && (reg_equiv_address[regno] || num_not_at_initial_offset))
2341 /* In this case, find_reloads would attempt to either use an
2342 incorrect address (if something is not at its initial offset)
2343 or substitute an replaced address into an insn (which loses
2344 if the offset is changed by some later action). So we simply
2345 return the replaced stack slot (assuming it is changed by
2346 elimination) and ignore the fact that this is actually a
2347 reference to the pseudo. Ensure we make a copy of the
2348 address in case it is shared. */
2349 new = eliminate_regs (reg_equiv_memory_loc[regno], mem_mode, 0);
2350 if (new != reg_equiv_memory_loc[regno])
2351 return copy_rtx (new);
2356 /* If this is the sum of an eliminable register and a constant, rework
2358 if (GET_CODE (XEXP (x, 0)) == REG
2359 && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER
2360 && CONSTANT_P (XEXP (x, 1)))
2362 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS];
2364 if (ep->from_rtx == XEXP (x, 0) && ep->can_eliminate)
2367 ep->ref_outside_mem = 1;
2369 /* The only time we want to replace a PLUS with a REG (this
2370 occurs when the constant operand of the PLUS is the negative
2371 of the offset) is when we are inside a MEM. We won't want
2372 to do so at other times because that would change the
2373 structure of the insn in a way that reload can't handle.
2374 We special-case the commonest situation in
2375 eliminate_regs_in_insn, so just replace a PLUS with a
2376 PLUS here, unless inside a MEM. */
2377 if (mem_mode && GET_CODE (XEXP (x, 1)) == CONST_INT
2378 && INTVAL (XEXP (x, 1)) == - ep->previous_offset)
2381 return gen_rtx (PLUS, Pmode, ep->to_rtx,
2382 plus_constant (XEXP (x, 1),
2383 ep->previous_offset));
2386 /* If the register is not eliminable, we are done since the other
2387 operand is a constant. */
2391 /* If this is part of an address, we want to bring any constant to the
2392 outermost PLUS. We will do this by doing register replacement in
2393 our operands and seeing if a constant shows up in one of them.
2395 We assume here this is part of an address (or a "load address" insn)
2396 since an eliminable register is not likely to appear in any other
2399 If we have (plus (eliminable) (reg)), we want to produce
2400 (plus (plus (replacement) (reg) (const))). If this was part of a
2401 normal add insn, (plus (replacement) (reg)) will be pushed as a
2402 reload. This is the desired action. */
2405 rtx new0 = eliminate_regs (XEXP (x, 0), mem_mode, 0);
2406 rtx new1 = eliminate_regs (XEXP (x, 1), mem_mode, 0);
2408 if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1))
2410 /* If one side is a PLUS and the other side is a pseudo that
2411 didn't get a hard register but has a reg_equiv_constant,
2412 we must replace the constant here since it may no longer
2413 be in the position of any operand. */
2414 if (GET_CODE (new0) == PLUS && GET_CODE (new1) == REG
2415 && REGNO (new1) >= FIRST_PSEUDO_REGISTER
2416 && reg_renumber[REGNO (new1)] < 0
2417 && reg_equiv_constant != 0
2418 && reg_equiv_constant[REGNO (new1)] != 0)
2419 new1 = reg_equiv_constant[REGNO (new1)];
2420 else if (GET_CODE (new1) == PLUS && GET_CODE (new0) == REG
2421 && REGNO (new0) >= FIRST_PSEUDO_REGISTER
2422 && reg_renumber[REGNO (new0)] < 0
2423 && reg_equiv_constant[REGNO (new0)] != 0)
2424 new0 = reg_equiv_constant[REGNO (new0)];
2426 new = form_sum (new0, new1);
2428 /* As above, if we are not inside a MEM we do not want to
2429 turn a PLUS into something else. We might try to do so here
2430 for an addition of 0 if we aren't optimizing. */
2431 if (! mem_mode && GET_CODE (new) != PLUS)
2432 return gen_rtx (PLUS, GET_MODE (x), new, const0_rtx);
2440 /* If we have something in XEXP (x, 0), the usual case, eliminate it. */
2443 new = eliminate_regs (XEXP (x, 0), mem_mode, 0);
2444 if (new != XEXP (x, 0))
2445 x = gen_rtx (EXPR_LIST, REG_NOTE_KIND (x), new, XEXP (x, 1));
2448 /* ... fall through ... */
2451 /* Now do eliminations in the rest of the chain. If this was
2452 an EXPR_LIST, this might result in allocating more memory than is
2453 strictly needed, but it simplifies the code. */
2456 new = eliminate_regs (XEXP (x, 1), mem_mode, 0);
2457 if (new != XEXP (x, 1))
2458 return gen_rtx (INSN_LIST, GET_MODE (x), XEXP (x, 0), new);
2466 case DIV: case UDIV:
2467 case MOD: case UMOD:
2468 case AND: case IOR: case XOR:
2469 case LSHIFT: case ASHIFT: case ROTATE:
2470 case ASHIFTRT: case LSHIFTRT: case ROTATERT:
2472 case GE: case GT: case GEU: case GTU:
2473 case LE: case LT: case LEU: case LTU:
2475 rtx new0 = eliminate_regs (XEXP (x, 0), mem_mode, 0);
2476 rtx new1 = XEXP (x, 1) ? eliminate_regs (XEXP (x, 1), mem_mode, 0) : 0;
2478 if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1))
2479 return gen_rtx (code, GET_MODE (x), new0, new1);
2487 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
2488 if (ep->to_rtx == XEXP (x, 0))
2490 if (code == PRE_DEC || code == POST_DEC)
2491 ep->offset += GET_MODE_SIZE (mem_mode);
2493 ep->offset -= GET_MODE_SIZE (mem_mode);
2496 /* Fall through to generic unary operation case. */
2498 case STRICT_LOW_PART:
2500 case SIGN_EXTEND: case ZERO_EXTEND:
2501 case TRUNCATE: case FLOAT_EXTEND: case FLOAT_TRUNCATE:
2502 case FLOAT: case FIX:
2503 case UNSIGNED_FIX: case UNSIGNED_FLOAT:
2507 new = eliminate_regs (XEXP (x, 0), mem_mode, 0);
2508 if (new != XEXP (x, 0))
2509 return gen_rtx (code, GET_MODE (x), new);
2513 /* Similar to above processing, but preserve SUBREG_WORD.
2514 Convert (subreg (mem)) to (mem) if not paradoxical.
2515 Also, if we have a non-paradoxical (subreg (pseudo)) and the
2516 pseudo didn't get a hard reg, we must replace this with the
2517 eliminated version of the memory location because push_reloads
2518 may do the replacement in certain circumstances. */
2519 if (GET_CODE (SUBREG_REG (x)) == REG
2520 && (GET_MODE_SIZE (GET_MODE (x))
2521 <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
2522 && reg_equiv_memory_loc != 0
2523 && reg_equiv_memory_loc[REGNO (SUBREG_REG (x))] != 0)
2525 new = eliminate_regs (reg_equiv_memory_loc[REGNO (SUBREG_REG (x))],
2528 /* If we didn't change anything, we must retain the pseudo. */
2529 if (new == reg_equiv_memory_loc[REGNO (SUBREG_REG (x))])
2532 /* Otherwise, ensure NEW isn't shared in case we have to reload
2534 new = copy_rtx (new);
2537 new = eliminate_regs (SUBREG_REG (x), mem_mode, 0);
2539 if (new != XEXP (x, 0))
2541 if (GET_CODE (new) == MEM
2542 && (GET_MODE_SIZE (GET_MODE (x))
2543 <= GET_MODE_SIZE (GET_MODE (new))))
2545 int offset = SUBREG_WORD (x) * UNITS_PER_WORD;
2546 enum machine_mode mode = GET_MODE (x);
2548 #if BYTES_BIG_ENDIAN
2549 offset += (MIN (UNITS_PER_WORD,
2550 GET_MODE_SIZE (GET_MODE (new)))
2551 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode)));
2554 PUT_MODE (new, mode);
2555 XEXP (new, 0) = plus_constant (XEXP (new, 0), offset);
2559 return gen_rtx (SUBREG, GET_MODE (x), new, SUBREG_WORD (x));
2565 /* If clobbering a register that is the replacement register for an
2566 elimination we still think can be peformed, note that it cannot
2567 be performed. Otherwise, we need not be concerned about it. */
2568 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
2569 if (ep->to_rtx == XEXP (x, 0))
2570 ep->can_eliminate = 0;
2577 /* Properly handle sharing input and constraint vectors. */
2578 if (ASM_OPERANDS_INPUT_VEC (x) != old_asm_operands_vec)
2580 /* When we come to a new vector not seen before,
2581 scan all its elements; keep the old vector if none
2582 of them changes; otherwise, make a copy. */
2583 old_asm_operands_vec = ASM_OPERANDS_INPUT_VEC (x);
2584 temp_vec = (rtx *) alloca (XVECLEN (x, 3) * sizeof (rtx));
2585 for (i = 0; i < ASM_OPERANDS_INPUT_LENGTH (x); i++)
2586 temp_vec[i] = eliminate_regs (ASM_OPERANDS_INPUT (x, i),
2589 for (i = 0; i < ASM_OPERANDS_INPUT_LENGTH (x); i++)
2590 if (temp_vec[i] != ASM_OPERANDS_INPUT (x, i))
2593 if (i == ASM_OPERANDS_INPUT_LENGTH (x))
2594 new_asm_operands_vec = old_asm_operands_vec;
2596 new_asm_operands_vec
2597 = gen_rtvec_v (ASM_OPERANDS_INPUT_LENGTH (x), temp_vec);
2600 /* If we had to copy the vector, copy the entire ASM_OPERANDS. */
2601 if (new_asm_operands_vec == old_asm_operands_vec)
2604 new = gen_rtx (ASM_OPERANDS, VOIDmode, ASM_OPERANDS_TEMPLATE (x),
2605 ASM_OPERANDS_OUTPUT_CONSTRAINT (x),
2606 ASM_OPERANDS_OUTPUT_IDX (x), new_asm_operands_vec,
2607 ASM_OPERANDS_INPUT_CONSTRAINT_VEC (x),
2608 ASM_OPERANDS_SOURCE_FILE (x),
2609 ASM_OPERANDS_SOURCE_LINE (x));
2610 new->volatil = x->volatil;
2615 /* Check for setting a register that we know about. */
2616 if (GET_CODE (SET_DEST (x)) == REG)
2618 /* See if this is setting the replacement register for an
2621 If DEST is the frame pointer, we do nothing because we assume that
2622 all assignments to the frame pointer are for non-local gotos and
2623 are being done at a time when they are valid and do not disturb
2624 anything else. Some machines want to eliminate a fake argument
2625 pointer with either the frame or stack pointer. Assignments to
2626 the frame pointer must not prevent this elimination. */
2628 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS];
2630 if (ep->to_rtx == SET_DEST (x)
2631 && SET_DEST (x) != frame_pointer_rtx)
2633 /* If it is being incrememented, adjust the offset. Otherwise,
2634 this elimination can't be done. */
2635 rtx src = SET_SRC (x);
2637 if (GET_CODE (src) == PLUS
2638 && XEXP (src, 0) == SET_DEST (x)
2639 && GET_CODE (XEXP (src, 1)) == CONST_INT)
2640 ep->offset -= INTVAL (XEXP (src, 1));
2642 ep->can_eliminate = 0;
2645 /* Now check to see we are assigning to a register that can be
2646 eliminated. If so, it must be as part of a PARALLEL, since we
2647 will not have been called if this is a single SET. So indicate
2648 that we can no longer eliminate this reg. */
2649 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS];
2651 if (ep->from_rtx == SET_DEST (x) && ep->can_eliminate)
2652 ep->can_eliminate = 0;
2655 /* Now avoid the loop below in this common case. */
2657 rtx new0 = eliminate_regs (SET_DEST (x), 0, 0);
2658 rtx new1 = eliminate_regs (SET_SRC (x), 0, 0);
2660 /* If SET_DEST changed from a REG to a MEM and INSN is non-zero,
2661 write a CLOBBER insn. */
2662 if (GET_CODE (SET_DEST (x)) == REG && GET_CODE (new0) == MEM
2664 emit_insn_after (gen_rtx (CLOBBER, VOIDmode, SET_DEST (x)), insn);
2666 if (new0 != SET_DEST (x) || new1 != SET_SRC (x))
2667 return gen_rtx (SET, VOIDmode, new0, new1);
2673 /* Our only special processing is to pass the mode of the MEM to our
2674 recursive call and copy the flags. While we are here, handle this
2675 case more efficiently. */
2676 new = eliminate_regs (XEXP (x, 0), GET_MODE (x), 0);
2677 if (new != XEXP (x, 0))
2679 new = gen_rtx (MEM, GET_MODE (x), new);
2680 new->volatil = x->volatil;
2681 new->unchanging = x->unchanging;
2682 new->in_struct = x->in_struct;
2689 /* Process each of our operands recursively. If any have changed, make a
2691 fmt = GET_RTX_FORMAT (code);
2692 for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++)
2696 new = eliminate_regs (XEXP (x, i), mem_mode, 0);
2697 if (new != XEXP (x, i) && ! copied)
2699 rtx new_x = rtx_alloc (code);
2700 bcopy (x, new_x, (sizeof (*new_x) - sizeof (new_x->fld)
2701 + (sizeof (new_x->fld[0])
2702 * GET_RTX_LENGTH (code))));
2708 else if (*fmt == 'E')
2711 for (j = 0; j < XVECLEN (x, i); j++)
2713 new = eliminate_regs (XVECEXP (x, i, j), mem_mode, insn);
2714 if (new != XVECEXP (x, i, j) && ! copied_vec)
2716 rtvec new_v = gen_rtvec_v (XVECLEN (x, i),
2717 &XVECEXP (x, i, 0));
2720 rtx new_x = rtx_alloc (code);
2721 bcopy (x, new_x, (sizeof (*new_x) - sizeof (new_x->fld)
2722 + (sizeof (new_x->fld[0])
2723 * GET_RTX_LENGTH (code))));
2727 XVEC (x, i) = new_v;
2730 XVECEXP (x, i, j) = new;
2738 /* Scan INSN and eliminate all eliminable registers in it.
2740 If REPLACE is nonzero, do the replacement destructively. Also
2741 delete the insn as dead it if it is setting an eliminable register.
2743 If REPLACE is zero, do all our allocations in reload_obstack.
2745 If no eliminations were done and this insn doesn't require any elimination
2746 processing (these are not identical conditions: it might be updating sp,
2747 but not referencing fp; this needs to be seen during reload_as_needed so
2748 that the offset between fp and sp can be taken into consideration), zero
2749 is returned. Otherwise, 1 is returned. */
2752 eliminate_regs_in_insn (insn, replace)
2756 rtx old_body = PATTERN (insn);
2759 struct elim_table *ep;
2762 push_obstacks (&reload_obstack, &reload_obstack);
2764 if (GET_CODE (old_body) == SET && GET_CODE (SET_DEST (old_body)) == REG
2765 && REGNO (SET_DEST (old_body)) < FIRST_PSEUDO_REGISTER)
2767 /* Check for setting an eliminable register. */
2768 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
2769 if (ep->from_rtx == SET_DEST (old_body) && ep->can_eliminate)
2771 /* In this case this insn isn't serving a useful purpose. We
2772 will delete it in reload_as_needed once we know that this
2773 elimination is, in fact, being done.
2775 If REPLACE isn't set, we can't delete this insn, but neededn't
2776 process it since it won't be used unless something changes. */
2778 delete_dead_insn (insn);
2783 /* Check for (set (reg) (plus (reg from) (offset))) where the offset
2784 in the insn is the negative of the offset in FROM. Substitute
2785 (set (reg) (reg to)) for the insn and change its code.
2787 We have to do this here, rather than in eliminate_regs, do that we can
2788 change the insn code. */
2790 if (GET_CODE (SET_SRC (old_body)) == PLUS
2791 && GET_CODE (XEXP (SET_SRC (old_body), 0)) == REG
2792 && GET_CODE (XEXP (SET_SRC (old_body), 1)) == CONST_INT)
2793 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS];
2795 if (ep->from_rtx == XEXP (SET_SRC (old_body), 0)
2796 && ep->can_eliminate
2797 && ep->offset == - INTVAL (XEXP (SET_SRC (old_body), 1)))
2799 PATTERN (insn) = gen_rtx (SET, VOIDmode,
2800 SET_DEST (old_body), ep->to_rtx);
2801 INSN_CODE (insn) = -1;
2807 old_asm_operands_vec = 0;
2809 /* Replace the body of this insn with a substituted form. If we changed
2810 something, return non-zero. If this is the final call for this
2811 insn (REPLACE is non-zero), do the elimination in REG_NOTES as well.
2813 If we are replacing a body that was a (set X (plus Y Z)), try to
2814 re-recognize the insn. We do this in case we had a simple addition
2815 but now can do this as a load-address. This saves an insn in this
2818 new_body = eliminate_regs (old_body, 0, replace ? insn : 0);
2819 if (new_body != old_body)
2821 if (GET_CODE (old_body) != SET || GET_CODE (SET_SRC (old_body)) != PLUS
2822 || ! validate_change (insn, &PATTERN (insn), new_body, 0))
2823 PATTERN (insn) = new_body;
2825 if (replace && REG_NOTES (insn))
2826 REG_NOTES (insn) = eliminate_regs (REG_NOTES (insn), 0, 0);
2830 /* Loop through all elimination pairs. See if any have changed and
2831 recalculate the number not at initial offset.
2833 Compute the maximum offset (minimum offset if the stack does not
2834 grow downward) for each elimination pair.
2836 We also detect a cases where register elimination cannot be done,
2837 namely, if a register would be both changed and referenced outside a MEM
2838 in the resulting insn since such an insn is often undefined and, even if
2839 not, we cannot know what meaning will be given to it. Note that it is
2840 valid to have a register used in an address in an insn that changes it
2841 (presumably with a pre- or post-increment or decrement).
2843 If anything changes, return nonzero. */
2845 num_not_at_initial_offset = 0;
2846 for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
2848 if (ep->previous_offset != ep->offset && ep->ref_outside_mem)
2849 ep->can_eliminate = 0;
2851 ep->ref_outside_mem = 0;
2853 if (ep->previous_offset != ep->offset)
2856 ep->previous_offset = ep->offset;
2857 if (ep->can_eliminate && ep->offset != ep->initial_offset)
2858 num_not_at_initial_offset++;
2860 #ifdef STACK_GROWS_DOWNWARD
2861 ep->max_offset = MAX (ep->max_offset, ep->offset);
2863 ep->max_offset = MIN (ep->max_offset, ep->offset);
2874 /* Given X, a SET or CLOBBER of DEST, if DEST is the target of a register
2875 replacement we currently believe is valid, mark it as not eliminable if X
2876 modifies DEST in any way other than by adding a constant integer to it.
2878 If DEST is the frame pointer, we do nothing because we assume that
2879 all assignments to the frame pointer are nonlocal gotos and are being done
2880 at a time when they are valid and do not disturb anything else.
2881 Some machines want to eliminate a fake argument pointer with either the
2882 frame or stack pointer. Assignments to the frame pointer must not prevent
2885 Called via note_stores from reload before starting its passes to scan
2886 the insns of the function. */
2889 mark_not_eliminable (dest, x)
2895 /* A SUBREG of a hard register here is just changing its mode. We should
2896 not see a SUBREG of an eliminable hard register, but check just in
2898 if (GET_CODE (dest) == SUBREG)
2899 dest = SUBREG_REG (dest);
2901 if (dest == frame_pointer_rtx)
2904 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
2905 if (reg_eliminate[i].can_eliminate && dest == reg_eliminate[i].to_rtx
2906 && (GET_CODE (x) != SET
2907 || GET_CODE (SET_SRC (x)) != PLUS
2908 || XEXP (SET_SRC (x), 0) != dest
2909 || GET_CODE (XEXP (SET_SRC (x), 1)) != CONST_INT))
2911 reg_eliminate[i].can_eliminate_previous
2912 = reg_eliminate[i].can_eliminate = 0;
2917 /* Kick all pseudos out of hard register REGNO.
2918 If GLOBAL is nonzero, try to find someplace else to put them.
2919 If DUMPFILE is nonzero, log actions taken on that file.
2921 If CANT_ELIMINATE is nonzero, it means that we are doing this spill
2922 because we found we can't eliminate some register. In the case, no pseudos
2923 are allowed to be in the register, even if they are only in a block that
2924 doesn't require spill registers, unlike the case when we are spilling this
2925 hard reg to produce another spill register.
2927 Return nonzero if any pseudos needed to be kicked out. */
2930 spill_hard_reg (regno, global, dumpfile, cant_eliminate)
2936 int something_changed = 0;
2939 SET_HARD_REG_BIT (forbidden_regs, regno);
2941 /* Spill every pseudo reg that was allocated to this reg
2942 or to something that overlaps this reg. */
2944 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
2945 if (reg_renumber[i] >= 0
2946 && reg_renumber[i] <= regno
2948 + HARD_REGNO_NREGS (reg_renumber[i],
2949 PSEUDO_REGNO_MODE (i))
2952 enum reg_class class = REGNO_REG_CLASS (regno);
2954 /* If this register belongs solely to a basic block which needed no
2955 spilling of any class that this register is contained in,
2956 leave it be, unless we are spilling this register because
2957 it was a hard register that can't be eliminated. */
2959 if (! cant_eliminate
2960 && basic_block_needs[0]
2961 && reg_basic_block[i] >= 0
2962 && basic_block_needs[(int) class][reg_basic_block[i]] == 0)
2966 for (p = reg_class_superclasses[(int) class];
2967 *p != LIM_REG_CLASSES; p++)
2968 if (basic_block_needs[(int) *p][reg_basic_block[i]] > 0)
2971 if (*p == LIM_REG_CLASSES)
2975 /* Mark it as no longer having a hard register home. */
2976 reg_renumber[i] = -1;
2977 /* We will need to scan everything again. */
2978 something_changed = 1;
2980 retry_global_alloc (i, forbidden_regs);
2982 alter_reg (i, regno);
2985 if (reg_renumber[i] == -1)
2986 fprintf (dumpfile, " Register %d now on stack.\n\n", i);
2988 fprintf (dumpfile, " Register %d now in %d.\n\n",
2989 i, reg_renumber[i]);
2993 return something_changed;
2996 /* Find all paradoxical subregs within X and update reg_max_ref_width. */
2999 scan_paradoxical_subregs (x)
3004 register enum rtx_code code = GET_CODE (x);
3021 if (GET_CODE (SUBREG_REG (x)) == REG
3022 && GET_MODE_SIZE (GET_MODE (x)) > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
3023 reg_max_ref_width[REGNO (SUBREG_REG (x))]
3024 = GET_MODE_SIZE (GET_MODE (x));
3028 fmt = GET_RTX_FORMAT (code);
3029 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3032 scan_paradoxical_subregs (XEXP (x, i));
3033 else if (fmt[i] == 'E')
3036 for (j = XVECLEN (x, i) - 1; j >=0; j--)
3037 scan_paradoxical_subregs (XVECEXP (x, i, j));
3042 struct hard_reg_n_uses { int regno; int uses; };
3045 hard_reg_use_compare (p1, p2)
3046 struct hard_reg_n_uses *p1, *p2;
3048 int tem = p1->uses - p2->uses;
3049 if (tem != 0) return tem;
3050 /* If regs are equally good, sort by regno,
3051 so that the results of qsort leave nothing to chance. */
3052 return p1->regno - p2->regno;
3055 /* Choose the order to consider regs for use as reload registers
3056 based on how much trouble would be caused by spilling one.
3057 Store them in order of decreasing preference in potential_reload_regs. */
3060 order_regs_for_reload ()
3066 struct hard_reg_n_uses hard_reg_n_uses[FIRST_PSEUDO_REGISTER];
3068 CLEAR_HARD_REG_SET (bad_spill_regs);
3070 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3071 potential_reload_regs[i] = -1;
3073 /* Count number of uses of each hard reg by pseudo regs allocated to it
3074 and then order them by decreasing use. */
3076 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3078 hard_reg_n_uses[i].uses = 0;
3079 hard_reg_n_uses[i].regno = i;
3082 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
3084 int regno = reg_renumber[i];
3087 int lim = regno + HARD_REGNO_NREGS (regno, PSEUDO_REGNO_MODE (i));
3089 hard_reg_n_uses[regno++].uses += reg_n_refs[i];
3091 large += reg_n_refs[i];
3094 /* Now fixed registers (which cannot safely be used for reloading)
3095 get a very high use count so they will be considered least desirable.
3096 Registers used explicitly in the rtl code are almost as bad. */
3098 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3102 hard_reg_n_uses[i].uses += 2 * large + 2;
3103 SET_HARD_REG_BIT (bad_spill_regs, i);
3105 else if (regs_explicitly_used[i])
3107 hard_reg_n_uses[i].uses += large + 1;
3108 /* ??? We are doing this here because of the potential that
3109 bad code may be generated if a register explicitly used in
3110 an insn was used as a spill register for that insn. But
3111 not using these are spill registers may lose on some machine.
3112 We'll have to see how this works out. */
3113 SET_HARD_REG_BIT (bad_spill_regs, i);
3116 hard_reg_n_uses[FRAME_POINTER_REGNUM].uses += 2 * large + 2;
3117 SET_HARD_REG_BIT (bad_spill_regs, FRAME_POINTER_REGNUM);
3119 #ifdef ELIMINABLE_REGS
3120 /* If registers other than the frame pointer are eliminable, mark them as
3122 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
3124 hard_reg_n_uses[reg_eliminate[i].from].uses += 2 * large + 2;
3125 SET_HARD_REG_BIT (bad_spill_regs, reg_eliminate[i].from);
3129 /* Prefer registers not so far used, for use in temporary loading.
3130 Among them, if REG_ALLOC_ORDER is defined, use that order.
3131 Otherwise, prefer registers not preserved by calls. */
3133 #ifdef REG_ALLOC_ORDER
3134 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3136 int regno = reg_alloc_order[i];
3138 if (hard_reg_n_uses[regno].uses == 0)
3139 potential_reload_regs[o++] = regno;
3142 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3144 if (hard_reg_n_uses[i].uses == 0 && call_used_regs[i])
3145 potential_reload_regs[o++] = i;
3147 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3149 if (hard_reg_n_uses[i].uses == 0 && ! call_used_regs[i])
3150 potential_reload_regs[o++] = i;
3154 qsort (hard_reg_n_uses, FIRST_PSEUDO_REGISTER,
3155 sizeof hard_reg_n_uses[0], hard_reg_use_compare);
3157 /* Now add the regs that are already used,
3158 preferring those used less often. The fixed and otherwise forbidden
3159 registers will be at the end of this list. */
3161 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3162 if (hard_reg_n_uses[i].uses != 0)
3163 potential_reload_regs[o++] = hard_reg_n_uses[i].regno;
3166 /* Reload pseudo-registers into hard regs around each insn as needed.
3167 Additional register load insns are output before the insn that needs it
3168 and perhaps store insns after insns that modify the reloaded pseudo reg.
3170 reg_last_reload_reg and reg_reloaded_contents keep track of
3171 which pseudo-registers are already available in reload registers.
3172 We update these for the reloads that we perform,
3173 as the insns are scanned. */
3176 reload_as_needed (first, live_known)
3186 bzero (spill_reg_rtx, sizeof spill_reg_rtx);
3187 reg_last_reload_reg = (rtx *) alloca (max_regno * sizeof (rtx));
3188 bzero (reg_last_reload_reg, max_regno * sizeof (rtx));
3189 reg_has_output_reload = (char *) alloca (max_regno);
3190 for (i = 0; i < n_spills; i++)
3192 reg_reloaded_contents[i] = -1;
3193 reg_reloaded_insn[i] = 0;
3196 /* Reset all offsets on eliminable registers to their initial values. */
3197 #ifdef ELIMINABLE_REGS
3198 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
3200 INITIAL_ELIMINATION_OFFSET (reg_eliminate[i].from, reg_eliminate[i].to,
3201 reg_eliminate[i].initial_offset)
3202 reg_eliminate[i].previous_offset
3203 = reg_eliminate[i].offset = reg_eliminate[i].initial_offset;
3206 INITIAL_FRAME_POINTER_OFFSET (reg_eliminate[0].initial_offset);
3207 reg_eliminate[0].previous_offset
3208 = reg_eliminate[0].offset = reg_eliminate[0].initial_offset;
3211 num_not_at_initial_offset = 0;
3213 for (insn = first; insn;)
3215 register rtx next = NEXT_INSN (insn);
3217 /* Notice when we move to a new basic block. */
3218 if (live_known && basic_block_needs && this_block + 1 < n_basic_blocks
3219 && insn == basic_block_head[this_block+1])
3222 /* If we pass a label, copy the offsets from the label information
3223 into the current offsets of each elimination. */
3224 if (GET_CODE (insn) == CODE_LABEL)
3226 num_not_at_initial_offset = 0;
3227 for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
3229 reg_eliminate[i].offset = reg_eliminate[i].previous_offset
3230 = offsets_at[CODE_LABEL_NUMBER (insn)][i];
3231 if (reg_eliminate[i].offset != reg_eliminate[i].initial_offset)
3232 num_not_at_initial_offset++;
3236 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
3238 rtx avoid_return_reg = 0;
3240 #ifdef SMALL_REGISTER_CLASSES
3241 /* Set avoid_return_reg if this is an insn
3242 that might use the value of a function call. */
3243 if (GET_CODE (insn) == CALL_INSN)
3245 if (GET_CODE (PATTERN (insn)) == SET)
3246 after_call = SET_DEST (PATTERN (insn));
3247 else if (GET_CODE (PATTERN (insn)) == PARALLEL
3248 && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET)
3249 after_call = SET_DEST (XVECEXP (PATTERN (insn), 0, 0));
3253 else if (after_call != 0
3254 && !(GET_CODE (PATTERN (insn)) == SET
3255 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx))
3257 if (reg_mentioned_p (after_call, PATTERN (insn)))
3258 avoid_return_reg = after_call;
3261 #endif /* SMALL_REGISTER_CLASSES */
3263 /* If this is a USE and CLOBBER of a MEM, ensure that any
3264 references to eliminable registers have been removed. */
3266 if ((GET_CODE (PATTERN (insn)) == USE
3267 || GET_CODE (PATTERN (insn)) == CLOBBER)
3268 && GET_CODE (XEXP (PATTERN (insn), 0)) == MEM)
3269 XEXP (XEXP (PATTERN (insn), 0), 0)
3270 = eliminate_regs (XEXP (XEXP (PATTERN (insn), 0), 0),
3271 GET_MODE (XEXP (PATTERN (insn), 0)), 0);
3273 /* If we need to do register elimination processing, do so.
3274 This might delete the insn, in which case we are done. */
3275 if (num_eliminable && GET_MODE (insn) == QImode)
3277 eliminate_regs_in_insn (insn, 1);
3278 if (GET_CODE (insn) == NOTE)
3285 if (GET_MODE (insn) == VOIDmode)
3287 /* First find the pseudo regs that must be reloaded for this insn.
3288 This info is returned in the tables reload_... (see reload.h).
3289 Also modify the body of INSN by substituting RELOAD
3290 rtx's for those pseudo regs. */
3293 bzero (reg_has_output_reload, max_regno);
3294 CLEAR_HARD_REG_SET (reg_is_output_reload);
3296 find_reloads (insn, 1, spill_indirect_levels, live_known,
3304 /* If this block has not had spilling done for a
3305 particular class, deactivate any optional reloads
3306 of that class lest they try to use a spill-reg which isn't
3307 available here. If we have any non-optionals that need a
3308 spill reg, abort. */
3310 for (class = 0; class < N_REG_CLASSES; class++)
3311 if (basic_block_needs[class] != 0
3312 && basic_block_needs[class][this_block] == 0)
3313 for (i = 0; i < n_reloads; i++)
3314 if (class == (int) reload_reg_class[i])
3316 if (reload_optional[i])
3317 reload_in[i] = reload_out[i] = reload_reg_rtx[i] = 0;
3318 else if (reload_reg_rtx[i] == 0)
3322 /* Now compute which reload regs to reload them into. Perhaps
3323 reusing reload regs from previous insns, or else output
3324 load insns to reload them. Maybe output store insns too.
3325 Record the choices of reload reg in reload_reg_rtx. */
3326 choose_reload_regs (insn, avoid_return_reg);
3328 /* Generate the insns to reload operands into or out of
3329 their reload regs. */
3330 emit_reload_insns (insn);
3332 /* Substitute the chosen reload regs from reload_reg_rtx
3333 into the insn's body (or perhaps into the bodies of other
3334 load and store insn that we just made for reloading
3335 and that we moved the structure into). */
3338 /* Any previously reloaded spilled pseudo reg, stored in this insn,
3339 is no longer validly lying around to save a future reload.
3340 Note that this does not detect pseudos that were reloaded
3341 for this insn in order to be stored in
3342 (obeying register constraints). That is correct; such reload
3343 registers ARE still valid. */
3344 note_stores (PATTERN (insn), forget_old_reloads_1);
3346 /* There may have been CLOBBER insns placed after INSN. So scan
3347 between INSN and NEXT and use them to forget old reloads. */
3348 for (x = NEXT_INSN (insn); x != next; x = NEXT_INSN (x))
3349 if (GET_CODE (x) == INSN && GET_CODE (PATTERN (x)) == CLOBBER)
3350 note_stores (PATTERN (x), forget_old_reloads_1);
3353 /* Likewise for regs altered by auto-increment in this insn.
3354 But note that the reg-notes are not changed by reloading:
3355 they still contain the pseudo-regs, not the spill regs. */
3356 for (x = REG_NOTES (insn); x; x = XEXP (x, 1))
3357 if (REG_NOTE_KIND (x) == REG_INC)
3359 /* See if this pseudo reg was reloaded in this insn.
3360 If so, its last-reload info is still valid
3361 because it is based on this insn's reload. */
3362 for (i = 0; i < n_reloads; i++)
3363 if (reload_out[i] == XEXP (x, 0))
3367 forget_old_reloads_1 (XEXP (x, 0));
3371 /* A reload reg's contents are unknown after a label. */
3372 if (GET_CODE (insn) == CODE_LABEL)
3373 for (i = 0; i < n_spills; i++)
3375 reg_reloaded_contents[i] = -1;
3376 reg_reloaded_insn[i] = 0;
3379 /* Don't assume a reload reg is still good after a call insn
3380 if it is a call-used reg. */
3381 if (GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == CALL_INSN)
3382 for (i = 0; i < n_spills; i++)
3383 if (call_used_regs[spill_regs[i]])
3385 reg_reloaded_contents[i] = -1;
3386 reg_reloaded_insn[i] = 0;
3389 /* In case registers overlap, allow certain insns to invalidate
3390 particular hard registers. */
3392 #ifdef INSN_CLOBBERS_REGNO_P
3393 for (i = 0 ; i < n_spills ; i++)
3394 if (INSN_CLOBBERS_REGNO_P (insn, spill_regs[i]))
3396 reg_reloaded_contents[i] = -1;
3397 reg_reloaded_insn[i] = 0;
3409 /* Discard all record of any value reloaded from X,
3410 or reloaded in X from someplace else;
3411 unless X is an output reload reg of the current insn.
3413 X may be a hard reg (the reload reg)
3414 or it may be a pseudo reg that was reloaded from. */
3417 forget_old_reloads_1 (x)
3423 if (GET_CODE (x) != REG)
3428 if (regno >= FIRST_PSEUDO_REGISTER)
3433 nr = HARD_REGNO_NREGS (regno, GET_MODE (x));
3434 /* Storing into a spilled-reg invalidates its contents.
3435 This can happen if a block-local pseudo is allocated to that reg
3436 and it wasn't spilled because this block's total need is 0.
3437 Then some insn might have an optional reload and use this reg. */
3438 for (i = 0; i < nr; i++)
3439 if (spill_reg_order[regno + i] >= 0
3440 /* But don't do this if the reg actually serves as an output
3441 reload reg in the current instruction. */
3443 || ! TEST_HARD_REG_BIT (reg_is_output_reload, regno + i)))
3445 reg_reloaded_contents[spill_reg_order[regno + i]] = -1;
3446 reg_reloaded_insn[spill_reg_order[regno + i]] = 0;
3450 /* Since value of X has changed,
3451 forget any value previously copied from it. */
3454 /* But don't forget a copy if this is the output reload
3455 that establishes the copy's validity. */
3456 if (n_reloads == 0 || reg_has_output_reload[regno + nr] == 0)
3457 reg_last_reload_reg[regno + nr] = 0;
3460 /* For each reload, the mode of the reload register. */
3461 static enum machine_mode reload_mode[MAX_RELOADS];
3463 /* For each reload, the largest number of registers it will require. */
3464 static int reload_nregs[MAX_RELOADS];
3466 /* Comparison function for qsort to decide which of two reloads
3467 should be handled first. *P1 and *P2 are the reload numbers. */
3470 reload_reg_class_lower (p1, p2)
3473 register int r1 = *p1, r2 = *p2;
3476 /* Consider required reloads before optional ones. */
3477 t = reload_optional[r1] - reload_optional[r2];
3481 /* Count all solitary classes before non-solitary ones. */
3482 t = ((reg_class_size[(int) reload_reg_class[r2]] == 1)
3483 - (reg_class_size[(int) reload_reg_class[r1]] == 1));
3487 /* Aside from solitaires, consider all multi-reg groups first. */
3488 t = reload_nregs[r2] - reload_nregs[r1];
3492 /* Consider reloads in order of increasing reg-class number. */
3493 t = (int) reload_reg_class[r1] - (int) reload_reg_class[r2];
3497 /* If reloads are equally urgent, sort by reload number,
3498 so that the results of qsort leave nothing to chance. */
3502 /* The following HARD_REG_SETs indicate when each hard register is
3503 used for a reload of various parts of the current insn. */
3505 /* If reg is in use as a reload reg for a RELOAD_OTHER reload. */
3506 static HARD_REG_SET reload_reg_used;
3507 /* If reg is in use for a RELOAD_FOR_INPUT_RELOAD_ADDRESS reload. */
3508 static HARD_REG_SET reload_reg_used_in_input_addr;
3509 /* If reg is in use for a RELOAD_FOR_OUTPUT_RELOAD_ADDRESS reload. */
3510 static HARD_REG_SET reload_reg_used_in_output_addr;
3511 /* If reg is in use for a RELOAD_FOR_OPERAND_ADDRESS reload. */
3512 static HARD_REG_SET reload_reg_used_in_op_addr;
3513 /* If reg is in use for a RELOAD_FOR_INPUT reload. */
3514 static HARD_REG_SET reload_reg_used_in_input;
3515 /* If reg is in use for a RELOAD_FOR_OUTPUT reload. */
3516 static HARD_REG_SET reload_reg_used_in_output;
3518 /* If reg is in use as a reload reg for any sort of reload. */
3519 static HARD_REG_SET reload_reg_used_at_all;
3521 /* Mark reg REGNO as in use for a reload of the sort spec'd by WHEN_NEEDED.
3522 MODE is used to indicate how many consecutive regs are actually used. */
3525 mark_reload_reg_in_use (regno, when_needed, mode)
3527 enum reload_when_needed when_needed;
3528 enum machine_mode mode;
3530 int nregs = HARD_REGNO_NREGS (regno, mode);
3533 for (i = regno; i < nregs + regno; i++)
3535 switch (when_needed)
3538 SET_HARD_REG_BIT (reload_reg_used, i);
3541 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
3542 SET_HARD_REG_BIT (reload_reg_used_in_input_addr, i);
3545 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
3546 SET_HARD_REG_BIT (reload_reg_used_in_output_addr, i);
3549 case RELOAD_FOR_OPERAND_ADDRESS:
3550 SET_HARD_REG_BIT (reload_reg_used_in_op_addr, i);
3553 case RELOAD_FOR_INPUT:
3554 SET_HARD_REG_BIT (reload_reg_used_in_input, i);
3557 case RELOAD_FOR_OUTPUT:
3558 SET_HARD_REG_BIT (reload_reg_used_in_output, i);
3562 SET_HARD_REG_BIT (reload_reg_used_at_all, i);
3566 /* 1 if reg REGNO is free as a reload reg for a reload of the sort
3567 specified by WHEN_NEEDED. */
3570 reload_reg_free_p (regno, when_needed)
3572 enum reload_when_needed when_needed;
3574 /* In use for a RELOAD_OTHER means it's not available for anything. */
3575 if (TEST_HARD_REG_BIT (reload_reg_used, regno))
3577 switch (when_needed)
3580 /* In use for anything means not available for a RELOAD_OTHER. */
3581 return ! TEST_HARD_REG_BIT (reload_reg_used_at_all, regno);
3583 /* The other kinds of use can sometimes share a register. */
3584 case RELOAD_FOR_INPUT:
3585 return (! TEST_HARD_REG_BIT (reload_reg_used_in_input, regno)
3586 && ! TEST_HARD_REG_BIT (reload_reg_used_in_op_addr, regno)
3587 && ! TEST_HARD_REG_BIT (reload_reg_used_in_input_addr, regno));
3588 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
3589 return (! TEST_HARD_REG_BIT (reload_reg_used_in_input_addr, regno)
3590 && ! TEST_HARD_REG_BIT (reload_reg_used_in_input, regno));
3591 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
3592 return (! TEST_HARD_REG_BIT (reload_reg_used_in_output_addr, regno)
3593 && ! TEST_HARD_REG_BIT (reload_reg_used_in_output, regno));
3594 case RELOAD_FOR_OPERAND_ADDRESS:
3595 return (! TEST_HARD_REG_BIT (reload_reg_used_in_op_addr, regno)
3596 && ! TEST_HARD_REG_BIT (reload_reg_used_in_input, regno)
3597 && ! TEST_HARD_REG_BIT (reload_reg_used_in_output, regno));
3598 case RELOAD_FOR_OUTPUT:
3599 return (! TEST_HARD_REG_BIT (reload_reg_used_in_op_addr, regno)
3600 && ! TEST_HARD_REG_BIT (reload_reg_used_in_output_addr, regno)
3601 && ! TEST_HARD_REG_BIT (reload_reg_used_in_output, regno));
3606 /* Return 1 if the value in reload reg REGNO, as used by a reload
3607 needed for the part of the insn specified by WHEN_NEEDED,
3608 is not in use for a reload in any prior part of the insn.
3610 We can assume that the reload reg was already tested for availability
3611 at the time it is needed, and we should not check this again,
3612 in case the reg has already been marked in use. */
3615 reload_reg_free_before_p (regno, when_needed)
3617 enum reload_when_needed when_needed;
3619 switch (when_needed)
3622 /* Since a RELOAD_OTHER reload claims the reg for the entire insn,
3623 its use starts from the beginning, so nothing can use it earlier. */
3626 /* If this use is for part of the insn,
3627 check the reg is not in use for any prior part. */
3628 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
3629 if (TEST_HARD_REG_BIT (reload_reg_used_in_op_addr, regno))
3631 case RELOAD_FOR_OUTPUT:
3632 if (TEST_HARD_REG_BIT (reload_reg_used_in_input, regno))
3634 case RELOAD_FOR_OPERAND_ADDRESS:
3635 if (TEST_HARD_REG_BIT (reload_reg_used_in_input_addr, regno))
3637 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
3638 case RELOAD_FOR_INPUT:
3644 /* Return 1 if the value in reload reg REGNO, as used by a reload
3645 needed for the part of the insn specified by WHEN_NEEDED,
3646 is still available in REGNO at the end of the insn.
3648 We can assume that the reload reg was already tested for availability
3649 at the time it is needed, and we should not check this again,
3650 in case the reg has already been marked in use. */
3653 reload_reg_reaches_end_p (regno, when_needed)
3655 enum reload_when_needed when_needed;
3657 switch (when_needed)
3660 /* Since a RELOAD_OTHER reload claims the reg for the entire insn,
3661 its value must reach the end. */
3664 /* If this use is for part of the insn,
3665 its value reaches if no subsequent part uses the same register. */
3666 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
3667 case RELOAD_FOR_INPUT:
3668 if (TEST_HARD_REG_BIT (reload_reg_used_in_op_addr, regno)
3669 || TEST_HARD_REG_BIT (reload_reg_used_in_output, regno))
3671 case RELOAD_FOR_OPERAND_ADDRESS:
3672 if (TEST_HARD_REG_BIT (reload_reg_used_in_output_addr, regno))
3674 case RELOAD_FOR_OUTPUT:
3675 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
3681 /* Vector of reload-numbers showing the order in which the reloads should
3683 short reload_order[MAX_RELOADS];
3685 /* Indexed by reload number, 1 if incoming value
3686 inherited from previous insns. */
3687 char reload_inherited[MAX_RELOADS];
3689 /* For an inherited reload, this is the insn the reload was inherited from,
3690 if we know it. Otherwise, this is 0. */
3691 rtx reload_inheritance_insn[MAX_RELOADS];
3693 /* If non-zero, this is a place to get the value of the reload,
3694 rather than using reload_in. */
3695 rtx reload_override_in[MAX_RELOADS];
3697 /* For each reload, the index in spill_regs of the spill register used,
3698 or -1 if we did not need one of the spill registers for this reload. */
3699 int reload_spill_index[MAX_RELOADS];
3701 /* Index of last register assigned as a spill register. We allocate in
3702 a round-robin fashio. */
3704 static last_spill_reg = 0;
3706 /* Find a spill register to use as a reload register for reload R.
3707 LAST_RELOAD is non-zero if this is the last reload for the insn being
3710 Set reload_reg_rtx[R] to the register allocated.
3712 If NOERROR is nonzero, we return 1 if successful,
3713 or 0 if we couldn't find a spill reg and we didn't change anything. */
3716 allocate_reload_reg (r, insn, last_reload, noerror)
3728 /* If we put this reload ahead, thinking it is a group,
3729 then insist on finding a group. Otherwise we can grab a
3730 reg that some other reload needs.
3731 (That can happen when we have a 68000 DATA_OR_FP_REG
3732 which is a group of data regs or one fp reg.)
3733 We need not be so restrictive if there are no more reloads
3736 ??? Really it would be nicer to have smarter handling
3737 for that kind of reg class, where a problem like this is normal.
3738 Perhaps those classes should be avoided for reloading
3739 by use of more alternatives. */
3741 int force_group = reload_nregs[r] > 1 && ! last_reload;
3743 /* If we want a single register and haven't yet found one,
3744 take any reg in the right class and not in use.
3745 If we want a consecutive group, here is where we look for it.
3747 We use two passes so we can first look for reload regs to
3748 reuse, which are already in use for other reloads in this insn,
3749 and only then use additional registers.
3750 I think that maximizing reuse is needed to make sure we don't
3751 run out of reload regs. Suppose we have three reloads, and
3752 reloads A and B can share regs. These need two regs.
3753 Suppose A and B are given different regs.
3754 That leaves none for C. */
3755 for (pass = 0; pass < 2; pass++)
3757 /* I is the index in spill_regs.
3758 We advance it round-robin between insns to use all spill regs
3759 equally, so that inherited reloads have a chance
3760 of leapfrogging each other. */
3762 for (count = 0, i = last_spill_reg; count < n_spills; count++)
3764 int class = (int) reload_reg_class[r];
3766 i = (i + 1) % n_spills;
3768 if (reload_reg_free_p (spill_regs[i], reload_when_needed[r])
3769 && TEST_HARD_REG_BIT (reg_class_contents[class], spill_regs[i])
3770 && HARD_REGNO_MODE_OK (spill_regs[i], reload_mode[r])
3771 /* Look first for regs to share, then for unshared. */
3772 && (pass || TEST_HARD_REG_BIT (reload_reg_used_at_all,
3775 int nr = HARD_REGNO_NREGS (spill_regs[i], reload_mode[r]);
3776 /* Avoid the problem where spilling a GENERAL_OR_FP_REG
3777 (on 68000) got us two FP regs. If NR is 1,
3778 we would reject both of them. */
3780 nr = CLASS_MAX_NREGS (reload_reg_class[r], reload_mode[r]);
3781 /* If we need only one reg, we have already won. */
3784 /* But reject a single reg if we demand a group. */
3789 /* Otherwise check that as many consecutive regs as we need
3791 Also, don't use for a group registers that are
3792 needed for nongroups. */
3793 if (! TEST_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]))
3796 regno = spill_regs[i] + nr - 1;
3797 if (!(TEST_HARD_REG_BIT (reg_class_contents[class], regno)
3798 && spill_reg_order[regno] >= 0
3799 && reload_reg_free_p (regno, reload_when_needed[r])
3800 && ! TEST_HARD_REG_BIT (counted_for_nongroups,
3810 /* If we found something on pass 1, omit pass 2. */
3811 if (count < n_spills)
3815 /* We should have found a spill register by now. */
3816 if (count == n_spills)
3825 /* Mark as in use for this insn the reload regs we use for this. */
3826 mark_reload_reg_in_use (spill_regs[i], reload_when_needed[r],
3829 new = spill_reg_rtx[i];
3831 if (new == 0 || GET_MODE (new) != reload_mode[r])
3832 spill_reg_rtx[i] = new = gen_rtx (REG, reload_mode[r], spill_regs[i]);
3834 reload_reg_rtx[r] = new;
3835 reload_spill_index[r] = i;
3836 regno = true_regnum (new);
3838 /* Detect when the reload reg can't hold the reload mode.
3839 This used to be one `if', but Sequent compiler can't handle that. */
3840 if (HARD_REGNO_MODE_OK (regno, reload_mode[r]))
3842 enum machine_mode test_mode = VOIDmode;
3844 test_mode = GET_MODE (reload_in[r]);
3845 /* If reload_in[r] has VOIDmode, it means we will load it
3846 in whatever mode the reload reg has: to wit, reload_mode[r].
3847 We have already tested that for validity. */
3848 /* Aside from that, we need to test that the expressions
3849 to reload from or into have modes which are valid for this
3850 reload register. Otherwise the reload insns would be invalid. */
3851 if (! (reload_in[r] != 0 && test_mode != VOIDmode
3852 && ! HARD_REGNO_MODE_OK (regno, test_mode)))
3853 if (! (reload_out[r] != 0
3854 && ! HARD_REGNO_MODE_OK (regno, GET_MODE (reload_out[r]))))
3855 /* The reg is OK. */
3859 /* The reg is not OK. */
3863 if (asm_noperands (PATTERN (insn)) < 0)
3864 /* It's the compiler's fault. */
3867 /* It's the user's fault; the operand's mode and constraint
3868 don't match. Disable this reload so we don't crash in final. */
3869 error_for_asm (insn,
3870 "`asm' operand constraint incompatible with operand size");
3873 reload_reg_rtx[r] = 0;
3874 reload_optional[r] = 1;
3875 reload_secondary_p[r] = 1;
3880 /* Assign hard reg targets for the pseudo-registers we must reload
3881 into hard regs for this insn.
3882 Also output the instructions to copy them in and out of the hard regs.
3884 For machines with register classes, we are responsible for
3885 finding a reload reg in the proper class. */
3888 choose_reload_regs (insn, avoid_return_reg)
3890 /* This argument is currently ignored. */
3891 rtx avoid_return_reg;
3894 int max_group_size = 1;
3895 enum reg_class group_class = NO_REGS;
3898 rtx save_reload_reg_rtx[MAX_RELOADS];
3899 char save_reload_inherited[MAX_RELOADS];
3900 rtx save_reload_inheritance_insn[MAX_RELOADS];
3901 rtx save_reload_override_in[MAX_RELOADS];
3902 int save_reload_spill_index[MAX_RELOADS];
3903 HARD_REG_SET save_reload_reg_used;
3904 HARD_REG_SET save_reload_reg_used_in_input_addr;
3905 HARD_REG_SET save_reload_reg_used_in_output_addr;
3906 HARD_REG_SET save_reload_reg_used_in_op_addr;
3907 HARD_REG_SET save_reload_reg_used_in_input;
3908 HARD_REG_SET save_reload_reg_used_in_output;
3909 HARD_REG_SET save_reload_reg_used_at_all;
3911 bzero (reload_inherited, MAX_RELOADS);
3912 bzero (reload_inheritance_insn, MAX_RELOADS * sizeof (rtx));
3913 bzero (reload_override_in, MAX_RELOADS * sizeof (rtx));
3915 CLEAR_HARD_REG_SET (reload_reg_used);
3916 CLEAR_HARD_REG_SET (reload_reg_used_at_all);
3917 CLEAR_HARD_REG_SET (reload_reg_used_in_input_addr);
3918 CLEAR_HARD_REG_SET (reload_reg_used_in_output_addr);
3919 CLEAR_HARD_REG_SET (reload_reg_used_in_op_addr);
3920 CLEAR_HARD_REG_SET (reload_reg_used_in_output);
3921 CLEAR_HARD_REG_SET (reload_reg_used_in_input);
3923 /* Distinguish output-only and input-only reloads
3924 because they can overlap with other things. */
3925 for (j = 0; j < n_reloads; j++)
3926 if (reload_when_needed[j] == RELOAD_OTHER
3927 && ! reload_needed_for_multiple[j])
3929 if (reload_in[j] == 0)
3931 /* But earlyclobber operands must stay as RELOAD_OTHER. */
3932 for (i = 0; i < n_earlyclobbers; i++)
3933 if (rtx_equal_p (reload_out[j], reload_earlyclobbers[i]))
3935 if (i == n_earlyclobbers)
3936 reload_when_needed[j] = RELOAD_FOR_OUTPUT;
3938 if (reload_out[j] == 0)
3939 reload_when_needed[j] = RELOAD_FOR_INPUT;
3941 if (reload_secondary_reload[j] >= 0
3942 && ! reload_needed_for_multiple[reload_secondary_reload[j]])
3943 reload_when_needed[reload_secondary_reload[j]]
3944 = reload_when_needed[j];
3947 #ifdef SMALL_REGISTER_CLASSES
3948 /* Don't bother with avoiding the return reg
3949 if we have no mandatory reload that could use it. */
3950 if (avoid_return_reg)
3953 int regno = REGNO (avoid_return_reg);
3955 = HARD_REGNO_NREGS (regno, GET_MODE (avoid_return_reg));
3958 for (r = regno; r < regno + nregs; r++)
3959 if (spill_reg_order[r] >= 0)
3960 for (j = 0; j < n_reloads; j++)
3961 if (!reload_optional[j] && reload_reg_rtx[j] == 0
3962 && (reload_in[j] != 0 || reload_out[j] != 0
3963 || reload_secondary_p[j])
3965 TEST_HARD_REG_BIT (reg_class_contents[(int) reload_reg_class[j]], r))
3968 avoid_return_reg = 0;
3970 #endif /* SMALL_REGISTER_CLASSES */
3972 #if 0 /* Not needed, now that we can always retry without inheritance. */
3973 /* See if we have more mandatory reloads than spill regs.
3974 If so, then we cannot risk optimizations that could prevent
3975 reloads from sharing one spill register.
3977 Since we will try finding a better register than reload_reg_rtx
3978 unless it is equal to reload_in or reload_out, count such reloads. */
3982 #ifdef SMALL_REGISTER_CLASSES
3983 int tem = (avoid_return_reg != 0);
3985 for (j = 0; j < n_reloads; j++)
3986 if (! reload_optional[j]
3987 && (reload_in[j] != 0 || reload_out[j] != 0 || reload_secondary_p[j])
3988 && (reload_reg_rtx[j] == 0
3989 || (! rtx_equal_p (reload_reg_rtx[j], reload_in[j])
3990 && ! rtx_equal_p (reload_reg_rtx[j], reload_out[j]))))
3997 #ifdef SMALL_REGISTER_CLASSES
3998 /* Don't use the subroutine call return reg for a reload
3999 if we are supposed to avoid it. */
4000 if (avoid_return_reg)
4002 int regno = REGNO (avoid_return_reg);
4004 = HARD_REGNO_NREGS (regno, GET_MODE (avoid_return_reg));
4007 for (r = regno; r < regno + nregs; r++)
4008 if (spill_reg_order[r] >= 0)
4009 SET_HARD_REG_BIT (reload_reg_used, r);
4011 #endif /* SMALL_REGISTER_CLASSES */
4013 /* In order to be certain of getting the registers we need,
4014 we must sort the reloads into order of increasing register class.
4015 Then our grabbing of reload registers will parallel the process
4016 that provided the reload registers.
4018 Also note whether any of the reloads wants a consecutive group of regs.
4019 If so, record the maximum size of the group desired and what
4020 register class contains all the groups needed by this insn. */
4022 for (j = 0; j < n_reloads; j++)
4024 reload_order[j] = j;
4025 reload_spill_index[j] = -1;
4028 = (reload_strict_low[j] && reload_out[j]
4029 ? GET_MODE (SUBREG_REG (reload_out[j]))
4030 : (reload_inmode[j] == VOIDmode
4031 || (GET_MODE_SIZE (reload_outmode[j])
4032 > GET_MODE_SIZE (reload_inmode[j])))
4033 ? reload_outmode[j] : reload_inmode[j]);
4035 reload_nregs[j] = CLASS_MAX_NREGS (reload_reg_class[j], reload_mode[j]);
4037 if (reload_nregs[j] > 1)
4039 max_group_size = MAX (reload_nregs[j], max_group_size);
4040 group_class = reg_class_superunion[(int)reload_reg_class[j]][(int)group_class];
4043 /* If we have already decided to use a certain register,
4044 don't use it in another way. */
4045 if (reload_reg_rtx[j])
4046 mark_reload_reg_in_use (REGNO (reload_reg_rtx[j]),
4047 reload_when_needed[j], reload_mode[j]);
4051 qsort (reload_order, n_reloads, sizeof (short), reload_reg_class_lower);
4053 bcopy (reload_reg_rtx, save_reload_reg_rtx, sizeof reload_reg_rtx);
4054 bcopy (reload_inherited, save_reload_inherited, sizeof reload_inherited);
4055 bcopy (reload_inheritance_insn, save_reload_inheritance_insn,
4056 sizeof reload_inheritance_insn);
4057 bcopy (reload_override_in, save_reload_override_in,
4058 sizeof reload_override_in);
4059 bcopy (reload_spill_index, save_reload_spill_index,
4060 sizeof reload_spill_index);
4061 COPY_HARD_REG_SET (save_reload_reg_used, reload_reg_used);
4062 COPY_HARD_REG_SET (save_reload_reg_used_at_all, reload_reg_used_at_all);
4063 COPY_HARD_REG_SET (save_reload_reg_used_in_output,
4064 reload_reg_used_in_output);
4065 COPY_HARD_REG_SET (save_reload_reg_used_in_input,
4066 reload_reg_used_in_input);
4067 COPY_HARD_REG_SET (save_reload_reg_used_in_input_addr,
4068 reload_reg_used_in_input_addr);
4069 COPY_HARD_REG_SET (save_reload_reg_used_in_output_addr,
4070 reload_reg_used_in_output_addr);
4071 COPY_HARD_REG_SET (save_reload_reg_used_in_op_addr,
4072 reload_reg_used_in_op_addr);
4074 /* Try first with inheritance, then turning it off. */
4076 for (inheritance = 1; inheritance >= 0; inheritance--)
4078 /* Process the reloads in order of preference just found.
4079 Beyond this point, subregs can be found in reload_reg_rtx.
4081 This used to look for an existing reloaded home for all
4082 of the reloads, and only then perform any new reloads.
4083 But that could lose if the reloads were done out of reg-class order
4084 because a later reload with a looser constraint might have an old
4085 home in a register needed by an earlier reload with a tighter constraint.
4087 To solve this, we make two passes over the reloads, in the order
4088 described above. In the first pass we try to inherit a reload
4089 from a previous insn. If there is a later reload that needs a
4090 class that is a proper subset of the class being processed, we must
4091 also allocate a spill register during the first pass.
4093 Then make a second pass over the reloads to allocate any reloads
4094 that haven't been given registers yet. */
4096 for (j = 0; j < n_reloads; j++)
4098 register int r = reload_order[j];
4100 /* Ignore reloads that got marked inoperative. */
4101 if (reload_out[r] == 0 && reload_in[r] == 0 && ! reload_secondary_p[r])
4104 /* If find_reloads chose a to use reload_in or reload_out as a reload
4105 register, we don't need to chose one. Otherwise, try even if it found
4106 one since we might save an insn if we find the value lying around. */
4107 if (reload_in[r] != 0 && reload_reg_rtx[r] != 0
4108 && (rtx_equal_p (reload_in[r], reload_reg_rtx[r])
4109 || rtx_equal_p (reload_out[r], reload_reg_rtx[r])))
4112 #if 0 /* No longer needed for correct operation.
4113 It might give better code, or might not; worth an experiment? */
4114 /* If this is an optional reload, we can't inherit from earlier insns
4115 until we are sure that any non-optional reloads have been allocated.
4116 The following code takes advantage of the fact that optional reloads
4117 are at the end of reload_order. */
4118 if (reload_optional[r] != 0)
4119 for (i = 0; i < j; i++)
4120 if ((reload_out[reload_order[i]] != 0
4121 || reload_in[reload_order[i]] != 0
4122 || reload_secondary_p[reload_order[i]])
4123 && ! reload_optional[reload_order[i]]
4124 && reload_reg_rtx[reload_order[i]] == 0)
4125 allocate_reload_reg (reload_order[i], insn, 0, inheritance);
4128 /* First see if this pseudo is already available as reloaded
4129 for a previous insn. We cannot try to inherit for reloads
4130 that are smaller than the maximum number of registers needed
4131 for groups unless the register we would allocate cannot be used
4134 We could check here to see if this is a secondary reload for
4135 an object that is already in a register of the desired class.
4136 This would avoid the need for the secondary reload register.
4137 But this is complex because we can't easily determine what
4138 objects might want to be loaded via this reload. So let a register
4139 be allocated here. In `emit_reload_insns' we suppress one of the
4140 loads in the case described above. */
4144 register int regno = -1;
4146 if (reload_in[r] == 0)
4148 else if (GET_CODE (reload_in[r]) == REG)
4149 regno = REGNO (reload_in[r]);
4150 else if (GET_CODE (reload_in_reg[r]) == REG)
4151 regno = REGNO (reload_in_reg[r]);
4153 /* This won't work, since REGNO can be a pseudo reg number.
4154 Also, it takes much more hair to keep track of all the things
4155 that can invalidate an inherited reload of part of a pseudoreg. */
4156 else if (GET_CODE (reload_in[r]) == SUBREG
4157 && GET_CODE (SUBREG_REG (reload_in[r])) == REG)
4158 regno = REGNO (SUBREG_REG (reload_in[r])) + SUBREG_WORD (reload_in[r]);
4161 if (regno >= 0 && reg_last_reload_reg[regno] != 0)
4163 i = spill_reg_order[REGNO (reg_last_reload_reg[regno])];
4165 if (reg_reloaded_contents[i] == regno
4166 && HARD_REGNO_MODE_OK (spill_regs[i], reload_mode[r])
4167 && TEST_HARD_REG_BIT (reg_class_contents[(int) reload_reg_class[r]],
4169 && (reload_nregs[r] == max_group_size
4170 || ! TEST_HARD_REG_BIT (reg_class_contents[(int) group_class],
4172 && reload_reg_free_p (spill_regs[i], reload_when_needed[r])
4173 && reload_reg_free_before_p (spill_regs[i],
4174 reload_when_needed[r]))
4176 /* If a group is needed, verify that all the subsequent
4177 registers still have their values intact. */
4179 = HARD_REGNO_NREGS (spill_regs[i], reload_mode[r]);
4182 for (k = 1; k < nr; k++)
4183 if (reg_reloaded_contents[spill_reg_order[spill_regs[i] + k]]
4189 /* Mark the register as in use for this part of
4191 mark_reload_reg_in_use (spill_regs[i],
4192 reload_when_needed[r],
4194 reload_reg_rtx[r] = reg_last_reload_reg[regno];
4195 reload_inherited[r] = 1;
4196 reload_inheritance_insn[r] = reg_reloaded_insn[i];
4197 reload_spill_index[r] = i;
4203 /* Here's another way to see if the value is already lying around. */
4205 && reload_in[r] != 0
4206 && ! reload_inherited[r]
4207 && reload_out[r] == 0
4208 && (CONSTANT_P (reload_in[r])
4209 || GET_CODE (reload_in[r]) == PLUS
4210 || GET_CODE (reload_in[r]) == REG
4211 || GET_CODE (reload_in[r]) == MEM)
4212 && (reload_nregs[r] == max_group_size
4213 || ! reg_classes_intersect_p (reload_reg_class[r], group_class)))
4216 = find_equiv_reg (reload_in[r], insn, reload_reg_class[r],
4217 -1, 0, 0, reload_mode[r]);
4222 if (GET_CODE (equiv) == REG)
4223 regno = REGNO (equiv);
4224 else if (GET_CODE (equiv) == SUBREG)
4226 regno = REGNO (SUBREG_REG (equiv));
4227 if (regno < FIRST_PSEUDO_REGISTER)
4228 regno += SUBREG_WORD (equiv);
4234 /* If we found a spill reg, reject it unless it is free
4235 and of the desired class. */
4237 && ((spill_reg_order[regno] >= 0
4238 && ! reload_reg_free_before_p (regno,
4239 reload_when_needed[r]))
4240 || ! TEST_HARD_REG_BIT (reg_class_contents[(int) reload_reg_class[r]],
4244 if (equiv != 0 && TEST_HARD_REG_BIT (reload_reg_used_at_all, regno))
4247 if (equiv != 0 && ! HARD_REGNO_MODE_OK (regno, reload_mode[r]))
4250 /* We found a register that contains the value we need.
4251 If this register is the same as an `earlyclobber' operand
4252 of the current insn, just mark it as a place to reload from
4253 since we can't use it as the reload register itself. */
4256 for (i = 0; i < n_earlyclobbers; i++)
4257 if (reg_overlap_mentioned_p (equiv, reload_earlyclobbers[i]))
4259 reload_override_in[r] = equiv;
4264 /* JRV: If the equiv register we have found is explicitly
4265 clobbered in the current insn, mark but don't use, as above. */
4267 if (equiv != 0 && regno_clobbered_p (regno, insn))
4269 reload_override_in[r] = equiv;
4273 /* If we found an equivalent reg, say no code need be generated
4274 to load it, and use it as our reload reg. */
4275 if (equiv != 0 && regno != FRAME_POINTER_REGNUM)
4277 reload_reg_rtx[r] = equiv;
4278 reload_inherited[r] = 1;
4279 /* If it is a spill reg,
4280 mark the spill reg as in use for this insn. */
4281 i = spill_reg_order[regno];
4283 mark_reload_reg_in_use (regno, reload_when_needed[r],
4288 /* If we found a register to use already, or if this is an optional
4289 reload, we are done. */
4290 if (reload_reg_rtx[r] != 0 || reload_optional[r] != 0)
4293 #if 0 /* No longer needed for correct operation. Might or might not
4294 give better code on the average. Want to experiment? */
4296 /* See if there is a later reload that has a class different from our
4297 class that intersects our class or that requires less register
4298 than our reload. If so, we must allocate a register to this
4299 reload now, since that reload might inherit a previous reload
4300 and take the only available register in our class. Don't do this
4301 for optional reloads since they will force all previous reloads
4302 to be allocated. Also don't do this for reloads that have been
4305 for (i = j + 1; i < n_reloads; i++)
4307 int s = reload_order[i];
4309 if ((reload_in[s] == 0 && reload_out[s] == 0 &&
4310 ! reload_secondary_p[s])
4311 || reload_optional[s])
4314 if ((reload_reg_class[s] != reload_reg_class[r]
4315 && reg_classes_intersect_p (reload_reg_class[r],
4316 reload_reg_class[s]))
4317 || reload_nregs[s] < reload_nregs[r])
4324 allocate_reload_reg (r, insn, j == n_reloads - 1, inheritance);
4328 /* Now allocate reload registers for anything non-optional that
4329 didn't get one yet. */
4330 for (j = 0; j < n_reloads; j++)
4332 register int r = reload_order[j];
4334 /* Ignore reloads that got marked inoperative. */
4335 if (reload_out[r] == 0 && reload_in[r] == 0 && ! reload_secondary_p[r])
4338 /* Skip reloads that already have a register allocated or are
4340 if (reload_reg_rtx[r] != 0 || reload_optional[r])
4343 if (! allocate_reload_reg (r, insn, j == n_reloads - 1, inheritance))
4347 /* If that loop got all the way, we have won. */
4352 /* Loop around and try without any inheritance. */
4353 /* First undo everything done by the failed attempt
4354 to allocate with inheritance. */
4355 bcopy (save_reload_reg_rtx, reload_reg_rtx, sizeof reload_reg_rtx);
4356 bcopy (save_reload_inherited, reload_inherited, sizeof reload_inherited);
4357 bcopy (save_reload_inheritance_insn, reload_inheritance_insn,
4358 sizeof reload_inheritance_insn);
4359 bcopy (save_reload_override_in, reload_override_in,
4360 sizeof reload_override_in);
4361 bcopy (save_reload_spill_index, reload_spill_index,
4362 sizeof reload_spill_index);
4363 COPY_HARD_REG_SET (reload_reg_used, save_reload_reg_used);
4364 COPY_HARD_REG_SET (reload_reg_used_at_all, save_reload_reg_used_at_all);
4365 COPY_HARD_REG_SET (reload_reg_used_in_input,
4366 save_reload_reg_used_in_input);
4367 COPY_HARD_REG_SET (reload_reg_used_in_output,
4368 save_reload_reg_used_in_output);
4369 COPY_HARD_REG_SET (reload_reg_used_in_input_addr,
4370 save_reload_reg_used_in_input_addr);
4371 COPY_HARD_REG_SET (reload_reg_used_in_output_addr,
4372 save_reload_reg_used_in_output_addr);
4373 COPY_HARD_REG_SET (reload_reg_used_in_op_addr,
4374 save_reload_reg_used_in_op_addr);
4377 /* If we thought we could inherit a reload, because it seemed that
4378 nothing else wanted the same reload register earlier in the insn,
4379 verify that assumption, now that all reloads have been assigned. */
4381 for (j = 0; j < n_reloads; j++)
4383 register int r = reload_order[j];
4385 if (reload_inherited[r] && reload_reg_rtx[r] != 0
4386 && ! reload_reg_free_before_p (true_regnum (reload_reg_rtx[r]),
4387 reload_when_needed[r]))
4388 reload_inherited[r] = 0;
4390 /* If we found a better place to reload from,
4391 validate it in the same fashion, if it is a reload reg. */
4392 if (reload_override_in[r]
4393 && (GET_CODE (reload_override_in[r]) == REG
4394 || GET_CODE (reload_override_in[r]) == SUBREG))
4396 int regno = true_regnum (reload_override_in[r]);
4397 if (spill_reg_order[regno] >= 0
4398 && ! reload_reg_free_before_p (regno, reload_when_needed[r]))
4399 reload_override_in[r] = 0;
4403 /* Now that reload_override_in is known valid,
4404 actually override reload_in. */
4405 for (j = 0; j < n_reloads; j++)
4406 if (reload_override_in[j])
4407 reload_in[j] = reload_override_in[j];
4409 /* If this reload won't be done because it has been cancelled or is
4410 optional and not inherited, clear reload_reg_rtx so other
4411 routines (such as subst_reloads) don't get confused. */
4412 for (j = 0; j < n_reloads; j++)
4413 if ((reload_optional[j] && ! reload_inherited[j])
4414 || (reload_in[j] == 0 && reload_out[j] == 0
4415 && ! reload_secondary_p[j]))
4416 reload_reg_rtx[j] = 0;
4418 /* Record which pseudos and which spill regs have output reloads. */
4419 for (j = 0; j < n_reloads; j++)
4421 register int r = reload_order[j];
4423 i = reload_spill_index[r];
4425 /* I is nonneg if this reload used one of the spill regs.
4426 If reload_reg_rtx[r] is 0, this is an optional reload
4427 that we opted to ignore. */
4428 if (reload_out[r] != 0 && GET_CODE (reload_out[r]) == REG
4429 && reload_reg_rtx[r] != 0)
4431 register int nregno = REGNO (reload_out[r]);
4432 int nr = HARD_REGNO_NREGS (nregno, reload_mode[r]);
4436 reg_has_output_reload[nregno + nr] = 1;
4438 SET_HARD_REG_BIT (reg_is_output_reload, spill_regs[i] + nr);
4441 if (reload_when_needed[r] != RELOAD_OTHER
4442 && reload_when_needed[r] != RELOAD_FOR_OUTPUT)
4448 /* Output insns to reload values in and out of the chosen reload regs. */
4451 emit_reload_insns (insn)
4455 rtx following_insn = NEXT_INSN (insn);
4456 rtx before_insn = insn;
4457 rtx first_output_reload_insn = NEXT_INSN (insn);
4458 rtx first_other_reload_insn = insn;
4459 rtx first_operand_address_reload_insn = insn;
4461 /* Values to be put in spill_reg_store are put here first. */
4462 rtx new_spill_reg_store[FIRST_PSEUDO_REGISTER];
4464 /* If this is a CALL_INSN preceeded by USE insns, any reload insns
4465 must go in front of the first USE insn, not in front of INSN. */
4467 if (GET_CODE (insn) == CALL_INSN && GET_CODE (PREV_INSN (insn)) == INSN
4468 && GET_CODE (PATTERN (PREV_INSN (insn))) == USE)
4469 while (GET_CODE (PREV_INSN (before_insn)) == INSN
4470 && GET_CODE (PATTERN (PREV_INSN (before_insn))) == USE)
4471 first_other_reload_insn = first_operand_address_reload_insn
4472 = before_insn = PREV_INSN (before_insn);
4474 /* Now output the instructions to copy the data into and out of the
4475 reload registers. Do these in the order that the reloads were reported,
4476 since reloads of base and index registers precede reloads of operands
4477 and the operands may need the base and index registers reloaded. */
4479 for (j = 0; j < n_reloads; j++)
4482 rtx oldequiv_reg = 0;
4483 rtx this_reload_insn = 0;
4487 if (old != 0 && ! reload_inherited[j]
4488 && ! rtx_equal_p (reload_reg_rtx[j], old)
4489 && reload_reg_rtx[j] != 0)
4491 register rtx reloadreg = reload_reg_rtx[j];
4493 enum machine_mode mode;
4497 /* Determine the mode to reload in.
4498 This is very tricky because we have three to choose from.
4499 There is the mode the insn operand wants (reload_inmode[J]).
4500 There is the mode of the reload register RELOADREG.
4501 There is the intrinsic mode of the operand, which we could find
4502 by stripping some SUBREGs.
4503 It turns out that RELOADREG's mode is irrelevant:
4504 we can change that arbitrarily.
4506 Consider (SUBREG:SI foo:QI) as an operand that must be SImode;
4507 then the reload reg may not support QImode moves, so use SImode.
4508 If foo is in memory due to spilling a pseudo reg, this is safe,
4509 because the QImode value is in the least significant part of a
4510 slot big enough for a SImode. If foo is some other sort of
4511 memory reference, then it is impossible to reload this case,
4512 so previous passes had better make sure this never happens.
4514 Then consider a one-word union which has SImode and one of its
4515 members is a float, being fetched as (SUBREG:SF union:SI).
4516 We must fetch that as SFmode because we could be loading into
4517 a float-only register. In this case OLD's mode is correct.
4519 Consider an immediate integer: it has VOIDmode. Here we need
4520 to get a mode from something else.
4522 In some cases, there is a fourth mode, the operand's
4523 containing mode. If the insn specifies a containing mode for
4524 this operand, it overrides all others.
4526 I am not sure whether the algorithm here is always right,
4527 but it does the right things in those cases. */
4529 mode = GET_MODE (old);
4530 if (mode == VOIDmode)
4531 mode = reload_inmode[j];
4532 if (reload_strict_low[j])
4533 mode = GET_MODE (SUBREG_REG (reload_in[j]));
4535 #ifdef SECONDARY_INPUT_RELOAD_CLASS
4536 /* If we need a secondary register for this operation, see if
4537 the value is already in a register in that class. Don't
4538 do this if the secondary register will be used as a scratch
4541 if (reload_secondary_reload[j] >= 0
4542 && reload_secondary_icode[j] == CODE_FOR_nothing)
4544 = find_equiv_reg (old, insn,
4545 reload_reg_class[reload_secondary_reload[j]],
4549 /* If reloading from memory, see if there is a register
4550 that already holds the same value. If so, reload from there.
4551 We can pass 0 as the reload_reg_p argument because
4552 any other reload has either already been emitted,
4553 in which case find_equiv_reg will see the reload-insn,
4554 or has yet to be emitted, in which case it doesn't matter
4555 because we will use this equiv reg right away. */
4558 && (GET_CODE (old) == MEM
4559 || (GET_CODE (old) == REG
4560 && REGNO (old) >= FIRST_PSEUDO_REGISTER
4561 && reg_renumber[REGNO (old)] < 0)))
4562 oldequiv = find_equiv_reg (old, insn, GENERAL_REGS,
4567 int regno = true_regnum (oldequiv);
4569 /* If OLDEQUIV is a spill register, don't use it for this
4570 if any other reload needs it at an earlier stage of this insn
4571 or at this stage. */
4572 if (spill_reg_order[regno] >= 0
4573 && (! reload_reg_free_p (regno, reload_when_needed[j])
4574 || ! reload_reg_free_before_p (regno,
4575 reload_when_needed[j])))
4578 /* If OLDEQUIV is not a spill register,
4579 don't use it if any other reload wants it. */
4580 if (spill_reg_order[regno] < 0)
4583 for (k = 0; k < n_reloads; k++)
4584 if (reload_reg_rtx[k] != 0 && k != j
4585 && reg_overlap_mentioned_p (reload_reg_rtx[k], oldequiv))
4595 else if (GET_CODE (oldequiv) == REG)
4596 oldequiv_reg = oldequiv;
4597 else if (GET_CODE (oldequiv) == SUBREG)
4598 oldequiv_reg = SUBREG_REG (oldequiv);
4600 /* Encapsulate both RELOADREG and OLDEQUIV into that mode,
4601 then load RELOADREG from OLDEQUIV. */
4603 if (GET_MODE (reloadreg) != mode)
4604 reloadreg = gen_rtx (REG, mode, REGNO (reloadreg));
4605 while (GET_CODE (oldequiv) == SUBREG && GET_MODE (oldequiv) != mode)
4606 oldequiv = SUBREG_REG (oldequiv);
4607 if (GET_MODE (oldequiv) != VOIDmode
4608 && mode != GET_MODE (oldequiv))
4609 oldequiv = gen_rtx (SUBREG, mode, oldequiv, 0);
4611 /* Decide where to put reload insn for this reload. */
4612 switch (reload_when_needed[j])
4614 case RELOAD_FOR_INPUT:
4616 where = first_operand_address_reload_insn;
4618 case RELOAD_FOR_INPUT_RELOAD_ADDRESS:
4619 where = first_other_reload_insn;
4621 case RELOAD_FOR_OUTPUT_RELOAD_ADDRESS:
4622 where = first_output_reload_insn;
4624 case RELOAD_FOR_OPERAND_ADDRESS:
4625 where = before_insn;
4630 /* Auto-increment addresses must be reloaded in a special way. */
4631 if (GET_CODE (oldequiv) == POST_INC
4632 || GET_CODE (oldequiv) == POST_DEC
4633 || GET_CODE (oldequiv) == PRE_INC
4634 || GET_CODE (oldequiv) == PRE_DEC)
4636 /* We are not going to bother supporting the case where a
4637 incremented register can't be copied directly from
4638 OLDEQUIV since this seems highly unlikely. */
4639 if (reload_secondary_reload[j] >= 0)
4641 /* Prevent normal processing of this reload. */
4643 /* Output a special code sequence for this case. */
4645 = inc_for_reload (reloadreg, oldequiv, reload_inc[j], where);
4648 /* If we are reloading a pseudo-register that was set by the previous
4649 insn, see if we can get rid of that pseudo-register entirely
4650 by redirecting the previous insn into our reload register. */
4652 else if (optimize && GET_CODE (old) == REG
4653 && REGNO (old) >= FIRST_PSEUDO_REGISTER
4654 && dead_or_set_p (insn, old)
4655 /* This is unsafe if some other reload
4656 uses the same reg first. */
4657 && (reload_when_needed[j] == RELOAD_OTHER
4658 || reload_when_needed[j] == RELOAD_FOR_INPUT
4659 || reload_when_needed[j] == RELOAD_FOR_INPUT_RELOAD_ADDRESS))
4661 rtx temp = PREV_INSN (insn);
4662 while (temp && GET_CODE (temp) == NOTE)
4663 temp = PREV_INSN (temp);
4665 && GET_CODE (temp) == INSN
4666 && GET_CODE (PATTERN (temp)) == SET
4667 && SET_DEST (PATTERN (temp)) == old
4668 /* Make sure we can access insn_operand_constraint. */
4669 && asm_noperands (PATTERN (temp)) < 0
4670 /* This is unsafe if prev insn rejects our reload reg. */
4671 && constraint_accepts_reg_p (insn_operand_constraint[recog_memoized (temp)][0],
4673 /* This is unsafe if operand occurs more than once in current
4674 insn. Perhaps some occurrences aren't reloaded. */
4675 && count_occurrences (PATTERN (insn), old) == 1
4676 /* Don't risk splitting a matching pair of operands. */
4677 && ! reg_mentioned_p (old, SET_SRC (PATTERN (temp))))
4679 /* Store into the reload register instead of the pseudo. */
4680 SET_DEST (PATTERN (temp)) = reloadreg;
4681 /* If these are the only uses of the pseudo reg,
4682 pretend for GDB it lives in the reload reg we used. */
4683 if (reg_n_deaths[REGNO (old)] == 1
4684 && reg_n_sets[REGNO (old)] == 1)
4686 reg_renumber[REGNO (old)] = REGNO (reload_reg_rtx[j]);
4687 alter_reg (REGNO (old), -1);
4693 /* We can't do that, so output an insn to load RELOADREG.
4694 Keep them in the following order:
4695 all reloads for input reload addresses,
4696 all reloads for ordinary input operands,
4697 all reloads for addresses of non-reloaded operands,
4698 the insn being reloaded,
4699 all reloads for addresses of output reloads,
4700 the output reloads. */
4703 #ifdef SECONDARY_INPUT_RELOAD_CLASS
4704 rtx second_reload_reg = 0;
4705 enum insn_code icode;
4707 /* If we have a secondary reload, pick up the secondary register
4708 and icode, if any. If OLDEQUIV and OLD are different or
4709 if this is an in-out reload, recompute whether or not we
4710 still need a secondary register and what the icode should
4711 be. If we still need a secondary register and the class or
4712 icode is different, go back to reloading from OLD if using
4713 OLDEQUIV means that we got the wrong type of register. We
4714 cannot have different class or icode due to an in-out reload
4715 because we don't make such reloads when both the input and
4716 output need secondary reload registers. */
4718 if (reload_secondary_reload[j] >= 0)
4720 int secondary_reload = reload_secondary_reload[j];
4721 second_reload_reg = reload_reg_rtx[secondary_reload];
4722 icode = reload_secondary_icode[j];
4724 if ((old != oldequiv && ! rtx_equal_p (old, oldequiv))
4725 || (reload_in[j] != 0 && reload_out[j] != 0))
4727 enum reg_class new_class
4728 = SECONDARY_INPUT_RELOAD_CLASS (reload_reg_class[j],
4731 if (new_class == NO_REGS)
4732 second_reload_reg = 0;
4735 enum insn_code new_icode;
4736 enum machine_mode new_mode;
4738 if (! TEST_HARD_REG_BIT (reg_class_contents[(int) new_class],
4739 REGNO (second_reload_reg)))
4743 new_icode = reload_in_optab[(int) mode];
4744 if (new_icode != CODE_FOR_nothing
4745 && ((insn_operand_predicate[(int) new_icode][0]
4746 && ! ((*insn_operand_predicate[(int) new_icode][0])
4748 || (insn_operand_predicate[(int) new_icode][1]
4749 && ! ((*insn_operand_predicate[(int) new_icode][1])
4750 (oldequiv, mode)))))
4751 new_icode = CODE_FOR_nothing;
4753 if (new_icode == CODE_FOR_nothing)
4756 new_mode = insn_operand_mode[new_icode][2];
4758 if (GET_MODE (second_reload_reg) != new_mode)
4760 if (!HARD_REGNO_MODE_OK (REGNO (second_reload_reg),
4765 = gen_reg_rtx (REG, new_mode,
4766 REGNO (second_reload_reg));
4772 /* If we still need a secondary reload register, check
4773 to see if it is being used as a scratch or intermediate
4774 register and generate code appropriately. */
4776 if (second_reload_reg)
4778 if (icode != CODE_FOR_nothing)
4780 reload_insn = emit_insn_before (GEN_FCN (icode)
4781 (reloadreg, oldequiv,
4784 if (this_reload_insn == 0)
4785 this_reload_insn = reload_insn;
4790 /* See if we need a scratch register to load the
4791 intermediate register (a tertiary reload). */
4792 enum insn_code tertiary_icode
4793 = reload_secondary_icode[secondary_reload];
4795 if (tertiary_icode != CODE_FOR_nothing)
4797 rtx third_reload_reg
4798 = reload_reg_rtx[reload_secondary_reload[secondary_reload]];
4801 = emit_insn_before ((GEN_FCN (tertiary_icode)
4806 if (this_reload_insn == 0)
4807 this_reload_insn = reload_insn;
4812 = gen_input_reload (second_reload_reg,
4814 if (this_reload_insn == 0)
4815 this_reload_insn = reload_insn;
4816 oldequiv = second_reload_reg;
4825 reload_insn = gen_input_reload (reloadreg,
4827 if (this_reload_insn == 0)
4828 this_reload_insn = reload_insn;
4831 #if defined(SECONDARY_INPUT_RELOAD_CLASS) && defined(PRESERVE_DEATH_INFO_REGNO_P)
4832 /* We may have to make a REG_DEAD note for the secondary reload
4833 register in the insns we just made. Find the last insn that
4834 mentioned the register. */
4835 if (! special && second_reload_reg
4836 && PRESERVE_DEATH_INFO_REGNO_P (REGNO (second_reload_reg)))
4841 prev != PREV_INSN (this_reload_insn);
4842 prev = PREV_INSN (prev))
4843 if (GET_RTX_CLASS (GET_CODE (prev) == 'i')
4844 && reg_overlap_mentioned_p (second_reload_reg,
4847 REG_NOTES (prev) = gen_rtx (EXPR_LIST, REG_DEAD,
4856 /* Update where to put other reload insns. */
4857 if (this_reload_insn)
4858 switch (reload_when_needed[j])
4860 case RELOAD_FOR_INPUT:
4862 if (first_other_reload_insn == first_operand_address_reload_insn)
4863 first_other_reload_insn = this_reload_insn;
4865 case RELOAD_FOR_OPERAND_ADDRESS:
4866 if (first_operand_address_reload_insn == before_insn)
4867 first_operand_address_reload_insn = this_reload_insn;
4868 if (first_other_reload_insn == before_insn)
4869 first_other_reload_insn = this_reload_insn;
4872 /* reload_inc[j] was formerly processed here. */
4875 /* Add a note saying the input reload reg
4876 dies in this insn, if anyone cares. */
4877 #ifdef PRESERVE_DEATH_INFO_REGNO_P
4879 && reload_reg_rtx[j] != old
4880 && reload_reg_rtx[j] != 0
4881 && reload_out[j] == 0
4882 && ! reload_inherited[j]
4883 && PRESERVE_DEATH_INFO_REGNO_P (REGNO (reload_reg_rtx[j])))
4885 register rtx reloadreg = reload_reg_rtx[j];
4888 /* We can't abort here because we need to support this for sched.c.
4889 It's not terrible to miss a REG_DEAD note, but we should try
4890 to figure out how to do this correctly. */
4891 /* The code below is incorrect for address-only reloads. */
4892 if (reload_when_needed[j] != RELOAD_OTHER
4893 && reload_when_needed[j] != RELOAD_FOR_INPUT)
4897 /* Add a death note to this insn, for an input reload. */
4899 if ((reload_when_needed[j] == RELOAD_OTHER
4900 || reload_when_needed[j] == RELOAD_FOR_INPUT)
4901 && ! dead_or_set_p (insn, reloadreg))
4903 = gen_rtx (EXPR_LIST, REG_DEAD,
4904 reloadreg, REG_NOTES (insn));
4907 /* When we inherit a reload, the last marked death of the reload reg
4908 may no longer really be a death. */
4909 if (reload_reg_rtx[j] != 0
4910 && PRESERVE_DEATH_INFO_REGNO_P (REGNO (reload_reg_rtx[j]))
4911 && reload_inherited[j])
4913 /* Handle inheriting an output reload.
4914 Remove the death note from the output reload insn. */
4915 if (reload_spill_index[j] >= 0
4916 && GET_CODE (reload_in[j]) == REG
4917 && spill_reg_store[reload_spill_index[j]] != 0
4918 && find_regno_note (spill_reg_store[reload_spill_index[j]],
4919 REG_DEAD, REGNO (reload_reg_rtx[j])))
4920 remove_death (REGNO (reload_reg_rtx[j]),
4921 spill_reg_store[reload_spill_index[j]]);
4922 /* Likewise for input reloads that were inherited. */
4923 else if (reload_spill_index[j] >= 0
4924 && GET_CODE (reload_in[j]) == REG
4925 && spill_reg_store[reload_spill_index[j]] == 0
4926 && reload_inheritance_insn[j] != 0
4927 && find_regno_note (reload_inheritance_insn[j], REG_DEAD,
4928 REGNO (reload_reg_rtx[j])))
4929 remove_death (REGNO (reload_reg_rtx[j]),
4930 reload_inheritance_insn[j]);
4935 /* We got this register from find_equiv_reg.
4936 Search back for its last death note and get rid of it.
4937 But don't search back too far.
4938 Don't go past a place where this reg is set,
4939 since a death note before that remains valid. */
4940 for (prev = PREV_INSN (insn);
4941 prev && GET_CODE (prev) != CODE_LABEL;
4942 prev = PREV_INSN (prev))
4943 if (GET_RTX_CLASS (GET_CODE (prev)) == 'i'
4944 && dead_or_set_p (prev, reload_reg_rtx[j]))
4946 if (find_regno_note (prev, REG_DEAD,
4947 REGNO (reload_reg_rtx[j])))
4948 remove_death (REGNO (reload_reg_rtx[j]), prev);
4954 /* We might have used find_equiv_reg above to choose an alternate
4955 place from which to reload. If so, and it died, we need to remove
4956 that death and move it to one of the insns we just made. */
4958 if (oldequiv_reg != 0
4959 && PRESERVE_DEATH_INFO_REGNO_P (true_regnum (oldequiv_reg)))
4963 for (prev = PREV_INSN (insn); prev && GET_CODE (prev) != CODE_LABEL;
4964 prev = PREV_INSN (prev))
4965 if (GET_RTX_CLASS (GET_CODE (prev)) == 'i'
4966 && dead_or_set_p (prev, oldequiv_reg))
4968 if (find_regno_note (prev, REG_DEAD, REGNO (oldequiv_reg)))
4970 for (prev1 = this_reload_insn;
4971 prev1; prev1 = PREV_INSN (prev1))
4972 if (GET_RTX_CLASS (GET_CODE (prev1) == 'i')
4973 && reg_overlap_mentioned_p (oldequiv_reg,
4976 REG_NOTES (prev1) = gen_rtx (EXPR_LIST, REG_DEAD,
4981 remove_death (REGNO (oldequiv_reg), prev);
4988 /* If we are reloading a register that was recently stored in with an
4989 output-reload, see if we can prove there was
4990 actually no need to store the old value in it. */
4992 if (optimize && reload_inherited[j] && reload_spill_index[j] >= 0
4993 /* This is unsafe if some other reload uses the same reg first. */
4994 && (reload_when_needed[j] == RELOAD_OTHER
4995 || reload_when_needed[j] == RELOAD_FOR_INPUT
4996 || reload_when_needed[j] == RELOAD_FOR_INPUT_RELOAD_ADDRESS)
4997 && GET_CODE (reload_in[j]) == REG
4999 /* There doesn't seem to be any reason to restrict this to pseudos
5000 and doing so loses in the case where we are copying from a
5001 register of the wrong class. */
5002 && REGNO (reload_in[j]) >= FIRST_PSEUDO_REGISTER
5004 && spill_reg_store[reload_spill_index[j]] != 0
5005 && dead_or_set_p (insn, reload_in[j])
5006 /* This is unsafe if operand occurs more than once in current
5007 insn. Perhaps some occurrences weren't reloaded. */
5008 && count_occurrences (PATTERN (insn), reload_in[j]) == 1)
5009 delete_output_reload (insn, j,
5010 spill_reg_store[reload_spill_index[j]]);
5012 /* Input-reloading is done. Now do output-reloading,
5013 storing the value from the reload-register after the main insn
5014 if reload_out[j] is nonzero.
5016 ??? At some point we need to support handling output reloads of
5017 JUMP_INSNs or insns that set cc0. */
5018 old = reload_out[j];
5020 && reload_reg_rtx[j] != old
5021 && reload_reg_rtx[j] != 0)
5023 register rtx reloadreg = reload_reg_rtx[j];
5024 register rtx second_reloadreg = 0;
5025 rtx prev_insn = PREV_INSN (first_output_reload_insn);
5027 enum machine_mode mode;
5030 /* An output operand that dies right away does need a reload,
5031 but need not be copied from it. Show the new location in the
5033 if ((GET_CODE (old) == REG || GET_CODE (old) == SCRATCH)
5034 && (note = find_reg_note (insn, REG_UNUSED, old)) != 0)
5036 XEXP (note, 0) = reload_reg_rtx[j];
5039 else if (GET_CODE (old) == SCRATCH)
5040 /* If we aren't optimizing, there won't be a REG_UNUSED note,
5041 but we don't want to make an output reload. */
5045 /* Strip off of OLD any size-increasing SUBREGs such as
5046 (SUBREG:SI foo:QI 0). */
5048 while (GET_CODE (old) == SUBREG && SUBREG_WORD (old) == 0
5049 && (GET_MODE_SIZE (GET_MODE (old))
5050 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (old)))))
5051 old = SUBREG_REG (old);
5054 /* If is a JUMP_INSN, we can't support output reloads yet. */
5055 if (GET_CODE (insn) == JUMP_INSN)
5058 /* Determine the mode to reload in.
5059 See comments above (for input reloading). */
5061 mode = GET_MODE (old);
5062 if (mode == VOIDmode)
5063 abort (); /* Should never happen for an output. */
5065 /* A strict-low-part output operand needs to be reloaded
5066 in the mode of the entire value. */
5067 if (reload_strict_low[j])
5069 mode = GET_MODE (SUBREG_REG (reload_out[j]));
5070 /* Encapsulate OLD into that mode. */
5071 /* If OLD is a subreg, then strip it, since the subreg will
5072 be altered by this very reload. */
5073 while (GET_CODE (old) == SUBREG && GET_MODE (old) != mode)
5074 old = SUBREG_REG (old);
5075 if (GET_MODE (old) != VOIDmode
5076 && mode != GET_MODE (old))
5077 old = gen_rtx (SUBREG, mode, old, 0);
5080 if (GET_MODE (reloadreg) != mode)
5081 reloadreg = gen_rtx (REG, mode, REGNO (reloadreg));
5083 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
5085 /* If we need two reload regs, set RELOADREG to the intermediate
5086 one, since it will be stored into OUT. We might need a secondary
5087 register only for an input reload, so check again here. */
5089 if (reload_secondary_reload[j] >= 0
5090 && (SECONDARY_OUTPUT_RELOAD_CLASS (reload_reg_class[j],
5094 second_reloadreg = reloadreg;
5095 reloadreg = reload_reg_rtx[reload_secondary_reload[j]];
5097 /* See if RELOADREG is to be used as a scratch register
5098 or as an intermediate register. */
5099 if (reload_secondary_icode[j] != CODE_FOR_nothing)
5101 emit_insn_before ((GEN_FCN (reload_secondary_icode[j])
5102 (old, second_reloadreg, reloadreg)),
5103 first_output_reload_insn);
5108 /* See if we need both a scratch and intermediate reload
5110 int secondary_reload = reload_secondary_reload[j];
5111 enum insn_code tertiary_icode
5112 = reload_secondary_icode[secondary_reload];
5115 if (GET_MODE (reloadreg) != mode)
5116 reloadreg = gen_rtx (REG, mode, REGNO (reloadreg));
5118 if (tertiary_icode != CODE_FOR_nothing)
5121 = reload_reg_rtx[reload_secondary_reload[secondary_reload]];
5122 pat = (GEN_FCN (tertiary_icode)
5123 (reloadreg, second_reloadreg, third_reloadreg));
5126 pat = gen_move_insn (reloadreg, second_reloadreg);
5128 emit_insn_before (pat, first_output_reload_insn);
5133 /* Output the last reload insn. */
5135 emit_insn_before (gen_move_insn (old, reloadreg),
5136 first_output_reload_insn);
5138 #ifdef PRESERVE_DEATH_INFO_REGNO_P
5139 /* If final will look at death notes for this reg,
5140 put one on the last output-reload insn to use it. Similarly
5141 for any secondary register. */
5142 if (PRESERVE_DEATH_INFO_REGNO_P (REGNO (reloadreg)))
5143 for (p = PREV_INSN (first_output_reload_insn);
5144 p != prev_insn; p = PREV_INSN (p))
5145 if (GET_RTX_CLASS (GET_CODE (p)) == 'i'
5146 && reg_overlap_mentioned_p (reloadreg, PATTERN (p)))
5147 REG_NOTES (p) = gen_rtx (EXPR_LIST, REG_DEAD,
5148 reloadreg, REG_NOTES (p));
5150 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
5152 && PRESERVE_DEATH_INFO_REGNO_P (REGNO (second_reloadreg)))
5153 for (p = PREV_INSN (first_output_reload_insn);
5154 p != prev_insn; p = PREV_INSN (p))
5155 if (GET_RTX_CLASS (GET_CODE (p)) == 'i'
5156 && reg_overlap_mentioned_p (second_reloadreg, PATTERN (p)))
5157 REG_NOTES (p) = gen_rtx (EXPR_LIST, REG_DEAD,
5158 second_reloadreg, REG_NOTES (p));
5161 /* Look at all insns we emitted, just to be safe. */
5162 for (p = NEXT_INSN (prev_insn); p != first_output_reload_insn;
5164 if (GET_RTX_CLASS (GET_CODE (p)) == 'i')
5166 /* If this output reload doesn't come from a spill reg,
5167 clear any memory of reloaded copies of the pseudo reg.
5168 If this output reload comes from a spill reg,
5169 reg_has_output_reload will make this do nothing. */
5170 note_stores (PATTERN (p), forget_old_reloads_1);
5172 if (reg_mentioned_p (reload_reg_rtx[j], PATTERN (p)))
5176 first_output_reload_insn = NEXT_INSN (prev_insn);
5179 if (reload_spill_index[j] >= 0)
5180 new_spill_reg_store[reload_spill_index[j]] = store_insn;
5183 /* Move death notes from INSN
5184 to output-operand-address and output reload insns. */
5185 #ifdef PRESERVE_DEATH_INFO_REGNO_P
5188 /* Loop over those insns, last ones first. */
5189 for (insn1 = PREV_INSN (following_insn); insn1 != insn;
5190 insn1 = PREV_INSN (insn1))
5191 if (GET_CODE (insn1) == INSN && GET_CODE (PATTERN (insn1)) == SET)
5193 rtx source = SET_SRC (PATTERN (insn1));
5194 rtx dest = SET_DEST (PATTERN (insn1));
5196 /* The note we will examine next. */
5197 rtx reg_notes = REG_NOTES (insn);
5198 /* The place that pointed to this note. */
5199 rtx *prev_reg_note = ®_NOTES (insn);
5201 /* If the note is for something used in the source of this
5202 reload insn, or in the output address, move the note. */
5205 rtx next_reg_notes = XEXP (reg_notes, 1);
5206 if (REG_NOTE_KIND (reg_notes) == REG_DEAD
5207 && GET_CODE (XEXP (reg_notes, 0)) == REG
5208 && ((GET_CODE (dest) != REG
5209 && reg_overlap_mentioned_p (XEXP (reg_notes, 0), dest))
5210 || reg_overlap_mentioned_p (XEXP (reg_notes, 0), source)))
5212 *prev_reg_note = next_reg_notes;
5213 XEXP (reg_notes, 1) = REG_NOTES (insn1);
5214 REG_NOTES (insn1) = reg_notes;
5217 prev_reg_note = &XEXP (reg_notes, 1);
5219 reg_notes = next_reg_notes;
5225 /* For all the spill regs newly reloaded in this instruction,
5226 record what they were reloaded from, so subsequent instructions
5227 can inherit the reloads.
5229 Update spill_reg_store for the reloads of this insn.
5230 Copy the elements that were updated in the loop above. */
5232 for (j = 0; j < n_reloads; j++)
5234 register int r = reload_order[j];
5235 register int i = reload_spill_index[r];
5237 /* I is nonneg if this reload used one of the spill regs.
5238 If reload_reg_rtx[r] is 0, this is an optional reload
5239 that we opted to ignore. */
5241 if (i >= 0 && reload_reg_rtx[r] != 0)
5243 /* First, clear out memory of what used to be in this spill reg.
5244 If consecutive registers are used, clear them all. */
5246 = HARD_REGNO_NREGS (spill_regs[i], GET_MODE (reload_reg_rtx[r]));
5249 for (k = 0; k < nr; k++)
5251 reg_reloaded_contents[spill_reg_order[spill_regs[i] + k]] = -1;
5252 reg_reloaded_insn[spill_reg_order[spill_regs[i] + k]] = 0;
5255 /* Maybe the spill reg contains a copy of reload_out. */
5256 if (reload_out[r] != 0 && GET_CODE (reload_out[r]) == REG)
5258 register int nregno = REGNO (reload_out[r]);
5260 spill_reg_store[i] = new_spill_reg_store[i];
5261 reg_last_reload_reg[nregno] = reload_reg_rtx[r];
5263 for (k = 0; k < nr; k++)
5265 reg_reloaded_contents[spill_reg_order[spill_regs[i] + k]]
5267 reg_reloaded_insn[spill_reg_order[spill_regs[i] + k]] = insn;
5271 /* Maybe the spill reg contains a copy of reload_in. */
5272 else if (reload_out[r] == 0
5273 && reload_in[r] != 0
5274 && (GET_CODE (reload_in[r]) == REG
5275 || GET_CODE (reload_in_reg[r]) == REG))
5277 register int nregno;
5278 if (GET_CODE (reload_in[r]) == REG)
5279 nregno = REGNO (reload_in[r]);
5281 nregno = REGNO (reload_in_reg[r]);
5283 /* If there are two separate reloads (one in and one out)
5284 for the same (hard or pseudo) reg,
5285 leave reg_last_reload_reg set
5286 based on the output reload.
5287 Otherwise, set it from this input reload. */
5288 if (!reg_has_output_reload[nregno]
5289 /* But don't do so if another input reload
5290 will clobber this one's value. */
5291 && reload_reg_reaches_end_p (spill_regs[i],
5292 reload_when_needed[r]))
5294 reg_last_reload_reg[nregno] = reload_reg_rtx[r];
5296 /* Unless we inherited this reload, show we haven't
5297 recently done a store. */
5298 if (! reload_inherited[r])
5299 spill_reg_store[i] = 0;
5301 for (k = 0; k < nr; k++)
5303 reg_reloaded_contents[spill_reg_order[spill_regs[i] + k]]
5305 reg_reloaded_insn[spill_reg_order[spill_regs[i] + k]]
5312 /* The following if-statement was #if 0'd in 1.34 (or before...).
5313 It's reenabled in 1.35 because supposedly nothing else
5314 deals with this problem. */
5316 /* If a register gets output-reloaded from a non-spill register,
5317 that invalidates any previous reloaded copy of it.
5318 But forget_old_reloads_1 won't get to see it, because
5319 it thinks only about the original insn. So invalidate it here. */
5320 if (i < 0 && reload_out[r] != 0 && GET_CODE (reload_out[r]) == REG)
5322 register int nregno = REGNO (reload_out[r]);
5323 reg_last_reload_reg[nregno] = 0;
5328 /* Emit code before BEFORE_INSN to perform an input reload of IN to RELOADREG.
5329 Returns first insn emitted. */
5332 gen_input_reload (reloadreg, in, before_insn)
5337 register rtx prev_insn = PREV_INSN (before_insn);
5339 /* How to do this reload can get quite tricky. Normally, we are being
5340 asked to reload a simple operand, such as a MEM, a constant, or a pseudo
5341 register that didn't get a hard register. In that case we can just
5342 call emit_move_insn.
5344 We can also be asked to reload a PLUS that adds either two registers or
5345 a register and a constant or MEM. This can occur during frame pointer
5346 elimination. That case if handled by trying to emit a single insn
5347 to perform the add. If it is not valid, we use a two insn sequence.
5349 Finally, we could be called to handle an 'o' constraint by putting
5350 an address into a register. In that case, we first try to do this
5351 with a named pattern of "reload_load_address". If no such pattern
5352 exists, we just emit a SET insn and hope for the best (it will normally
5353 be valid on machines that use 'o').
5355 This entire process is made complex because reload will never
5356 process the insns we generate here and so we must ensure that
5357 they will fit their constraints and also by the fact that parts of
5358 IN might be being reloaded separately and replaced with spill registers.
5359 Because of this, we are, in some sense, just guessing the right approach
5360 here. The one listed above seems to work.
5362 ??? At some point, this whole thing needs to be rethought. */
5364 if (GET_CODE (in) == PLUS
5365 && GET_CODE (XEXP (in, 0)) == REG
5366 && (GET_CODE (XEXP (in, 1)) == REG
5367 || CONSTANT_P (XEXP (in, 1))
5368 || GET_CODE (XEXP (in, 1)) == MEM))
5370 /* We need to compute the sum of what is either a register and a
5371 constant, a register and memory, or a hard register and a pseudo
5372 register and put it into the reload register. The best possible way
5373 of doing this is if the machine has a three-operand ADD insn that
5374 accepts the required operands.
5376 The simplest approach is to try to generate such an insn and see if it
5377 is recognized and matches its constraints. If so, it can be used.
5379 It might be better not to actually emit the insn unless it is valid,
5380 but we need to pass the insn as an operand to `recog' and it is
5381 simpler to emit and then delete the insn if not valid than to
5384 rtx move_operand, other_operand, insn;
5387 /* Since constraint checking is strict, commutativity won't be
5388 checked, so we need to do that here to avoid spurious failure
5389 if the add instruction is two-address and the second operand
5390 of the add is the same as the reload reg, which is frequently
5391 the case. If the insn would be A = B + A, rearrange it so
5392 it will be A = A + B as constrain_operands expects. */
5394 if (GET_CODE (XEXP (in, 1)) == REG
5395 && REGNO (reloadreg) == REGNO (XEXP (in, 1)))
5396 in = gen_rtx (PLUS, GET_MODE (in), XEXP (in, 1), XEXP (in, 0));
5398 insn = emit_insn_before (gen_rtx (SET, VOIDmode, reloadreg, in),
5400 code = recog_memoized (insn);
5404 insn_extract (insn);
5405 /* We want constrain operands to treat this insn strictly in
5406 its validity determination, i.e., the way it would after reload
5408 if (constrain_operands (code, 1))
5412 if (PREV_INSN (insn))
5413 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
5414 if (NEXT_INSN (insn))
5415 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
5417 /* If that failed, we must use a conservative two-insn sequence.
5418 use move to copy constant, MEM, or pseudo register to the reload
5419 register since "move" will be able to handle arbitrary operand, unlike
5420 add which can't, in general. Then add the registers.
5422 If there is another way to do this for a specific machine, a
5423 DEFINE_PEEPHOLE should be specified that recognizes the sequence
5426 if (CONSTANT_P (XEXP (in, 1))
5427 || GET_CODE (XEXP (in, 1)) == MEM
5428 || (GET_CODE (XEXP (in, 1)) == REG
5429 && REGNO (XEXP (in, 1)) >= FIRST_PSEUDO_REGISTER))
5430 move_operand = XEXP (in, 1), other_operand = XEXP (in, 0);
5432 move_operand = XEXP (in, 0), other_operand = XEXP (in, 1);
5434 emit_insn_before (gen_move_insn (reloadreg, move_operand), before_insn);
5435 emit_insn_before (gen_add2_insn (reloadreg, other_operand), before_insn);
5438 /* If IN is a simple operand, use gen_move_insn. */
5439 else if (GET_RTX_CLASS (GET_CODE (in)) == 'o' || GET_CODE (in) == SUBREG)
5440 emit_insn_before (gen_move_insn (reloadreg, in), before_insn);
5442 #ifdef HAVE_reload_load_address
5443 else if (HAVE_reload_load_address)
5444 emit_insn_before (gen_reload_load_address (reloadreg, in), before_insn);
5447 /* Otherwise, just write (set REGLOADREG IN) and hope for the best. */
5449 emit_insn_before (gen_rtx (SET, VOIDmode, reloadreg, in), before_insn);
5451 /* Return the first insn emitted.
5452 We can not just return PREV_INSN (before_insn), because there may have
5453 been multiple instructions emitted. Also note that gen_move_insn may
5454 emit more than one insn itself, so we can not assume that there is one
5455 insn emitted per emit_insn_before call. */
5457 return NEXT_INSN (prev_insn);
5460 /* Delete a previously made output-reload
5461 whose result we now believe is not needed.
5462 First we double-check.
5464 INSN is the insn now being processed.
5465 OUTPUT_RELOAD_INSN is the insn of the output reload.
5466 J is the reload-number for this insn. */
5469 delete_output_reload (insn, j, output_reload_insn)
5472 rtx output_reload_insn;
5476 /* Get the raw pseudo-register referred to. */
5478 rtx reg = reload_in[j];
5479 while (GET_CODE (reg) == SUBREG)
5480 reg = SUBREG_REG (reg);
5482 /* If the pseudo-reg we are reloading is no longer referenced
5483 anywhere between the store into it and here,
5484 and no jumps or labels intervene, then the value can get
5485 here through the reload reg alone.
5486 Otherwise, give up--return. */
5487 for (i1 = NEXT_INSN (output_reload_insn);
5488 i1 != insn; i1 = NEXT_INSN (i1))
5490 if (GET_CODE (i1) == CODE_LABEL || GET_CODE (i1) == JUMP_INSN)
5492 if ((GET_CODE (i1) == INSN || GET_CODE (i1) == CALL_INSN)
5493 && reg_mentioned_p (reg, PATTERN (i1)))
5497 /* If this insn will store in the pseudo again,
5498 the previous store can be removed. */
5499 if (reload_out[j] == reload_in[j])
5500 delete_insn (output_reload_insn);
5502 /* See if the pseudo reg has been completely replaced
5503 with reload regs. If so, delete the store insn
5504 and forget we had a stack slot for the pseudo. */
5505 else if (reg_n_deaths[REGNO (reg)] == 1
5506 && reg_basic_block[REGNO (reg)] >= 0
5507 && find_regno_note (insn, REG_DEAD, REGNO (reg)))
5511 /* We know that it was used only between here
5512 and the beginning of the current basic block.
5513 (We also know that the last use before INSN was
5514 the output reload we are thinking of deleting, but never mind that.)
5515 Search that range; see if any ref remains. */
5516 for (i2 = PREV_INSN (insn); i2; i2 = PREV_INSN (i2))
5518 rtx set = single_set (i2);
5520 /* Uses which just store in the pseudo don't count,
5521 since if they are the only uses, they are dead. */
5522 if (set != 0 && SET_DEST (set) == reg)
5524 if (GET_CODE (i2) == CODE_LABEL
5525 || GET_CODE (i2) == JUMP_INSN)
5527 if ((GET_CODE (i2) == INSN || GET_CODE (i2) == CALL_INSN)
5528 && reg_mentioned_p (reg, PATTERN (i2)))
5529 /* Some other ref remains;
5530 we can't do anything. */
5534 /* Delete the now-dead stores into this pseudo. */
5535 for (i2 = PREV_INSN (insn); i2; i2 = PREV_INSN (i2))
5537 rtx set = single_set (i2);
5539 if (set != 0 && SET_DEST (set) == reg)
5541 if (GET_CODE (i2) == CODE_LABEL
5542 || GET_CODE (i2) == JUMP_INSN)
5546 /* For the debugging info,
5547 say the pseudo lives in this reload reg. */
5548 reg_renumber[REGNO (reg)] = REGNO (reload_reg_rtx[j]);
5549 alter_reg (REGNO (reg), -1);
5554 /* Output reload-insns to reload VALUE into RELOADREG.
5555 VALUE is a autoincrement or autodecrement RTX whose operand
5556 is a register or memory location;
5557 so reloading involves incrementing that location.
5559 INC_AMOUNT is the number to increment or decrement by (always positive).
5560 This cannot be deduced from VALUE.
5562 INSN is the insn before which the new insns should be emitted.
5564 The return value is the first of the insns emitted. */
5567 inc_for_reload (reloadreg, value, inc_amount, insn)
5573 /* REG or MEM to be copied and incremented. */
5574 rtx incloc = XEXP (value, 0);
5575 /* Nonzero if increment after copying. */
5576 int post = (GET_CODE (value) == POST_DEC || GET_CODE (value) == POST_INC);
5578 /* No hard register is equivalent to this register after
5579 inc/dec operation. If REG_LAST_RELOAD_REG were non-zero,
5580 we could inc/dec that register as well (maybe even using it for
5581 the source), but I'm not sure it's worth worrying about. */
5582 if (GET_CODE (incloc) == REG)
5583 reg_last_reload_reg[REGNO (incloc)] = 0;
5585 if (GET_CODE (value) == PRE_DEC || GET_CODE (value) == POST_DEC)
5586 inc_amount = - inc_amount;
5588 /* First handle preincrement, which is simpler. */
5591 /* If incrementing a register, assume we can
5592 output an insn to increment it directly. */
5593 if (GET_CODE (incloc) == REG &&
5594 (REGNO (incloc) < FIRST_PSEUDO_REGISTER
5595 || reg_renumber[REGNO (incloc)] >= 0))
5598 = emit_insn_before (gen_add2_insn (incloc,
5599 gen_rtx (CONST_INT, VOIDmode,
5602 emit_insn_before (gen_move_insn (reloadreg, incloc), insn);
5606 /* Else we must not assume we can increment the location directly
5607 (even though on many target machines we can);
5608 copy it to the reload register, increment there, then save back. */
5611 = emit_insn_before (gen_move_insn (reloadreg, incloc), insn);
5612 emit_insn_before (gen_add2_insn (reloadreg,
5613 gen_rtx (CONST_INT, VOIDmode,
5616 emit_insn_before (gen_move_insn (incloc, reloadreg), insn);
5621 Because this might be a jump insn or a compare, and because RELOADREG
5622 may not be available after the insn in an input reload,
5623 we must do the incrementation before the insn being reloaded for. */
5626 /* Copy the value, then increment it. */
5628 = emit_insn_before (gen_move_insn (reloadreg, incloc), insn);
5630 /* If incrementing a register, assume we can
5631 output an insn to increment it directly. */
5632 if (GET_CODE (incloc) == REG &&
5633 (REGNO (incloc) < FIRST_PSEUDO_REGISTER
5634 || reg_renumber[REGNO (incloc)] >= 0))
5636 emit_insn_before (gen_add2_insn (incloc,
5637 gen_rtx (CONST_INT, VOIDmode,
5642 /* Else we must not assume we can increment INCLOC
5643 (even though on many target machines we can);
5644 increment the copy in the reload register,
5645 save that back, then decrement the reload register
5646 so it has the original value. */
5648 emit_insn_before (gen_add2_insn (reloadreg,
5649 gen_rtx (CONST_INT, VOIDmode,
5652 emit_insn_before (gen_move_insn (incloc, reloadreg), insn);
5653 emit_insn_before (gen_sub2_insn (reloadreg,
5654 gen_rtx (CONST_INT, VOIDmode,
5662 /* Return 1 if we are certain that the constraint-string STRING allows
5663 the hard register REG. Return 0 if we can't be sure of this. */
5666 constraint_accepts_reg_p (string, reg)
5671 int regno = true_regnum (reg);
5674 /* Initialize for first alternative. */
5676 /* Check that each alternative contains `g' or `r'. */
5678 switch (c = *string++)
5681 /* If an alternative lacks `g' or `r', we lose. */
5684 /* If an alternative lacks `g' or `r', we lose. */
5687 /* Initialize for next alternative. */
5692 /* Any general reg wins for this alternative. */
5693 if (TEST_HARD_REG_BIT (reg_class_contents[(int) GENERAL_REGS], regno))
5697 /* Any reg in specified class wins for this alternative. */
5699 int class = REG_CLASS_FROM_LETTER (c);
5701 if (TEST_HARD_REG_BIT (reg_class_contents[class], regno))
5707 /* Return the number of places FIND appears within X, but don't count
5708 an occurrence if some SET_DEST is FIND. */
5711 count_occurrences (x, find)
5712 register rtx x, find;
5715 register enum rtx_code code;
5716 register char *format_ptr;
5724 code = GET_CODE (x);
5739 if (SET_DEST (x) == find)
5740 return count_occurrences (SET_SRC (x), find);
5744 format_ptr = GET_RTX_FORMAT (code);
5747 for (i = 0; i < GET_RTX_LENGTH (code); i++)
5749 switch (*format_ptr++)
5752 count += count_occurrences (XEXP (x, i), find);
5756 if (XVEC (x, i) != NULL)
5758 for (j = 0; j < XVECLEN (x, i); j++)
5759 count += count_occurrences (XVECEXP (x, i, j), find);
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