Major cutover to using system.h:
[gcc.git] / gcc / explow.c
1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987, 91, 94, 95, 96, 97, 1998 Free Software Foundation, Inc.
3
4 This file is part of GNU CC.
5
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)
9 any later version.
10
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.
15
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
20
21
22 #include "config.h"
23 #include "system.h"
24 #include "rtl.h"
25 #include "tree.h"
26 #include "flags.h"
27 #include "expr.h"
28 #include "hard-reg-set.h"
29 #include "insn-config.h"
30 #include "recog.h"
31 #include "insn-flags.h"
32 #include "insn-codes.h"
33
34 static rtx break_out_memory_refs PROTO((rtx));
35 static void emit_stack_probe PROTO((rtx));
36 /* Return an rtx for the sum of X and the integer C.
37
38 This function should be used via the `plus_constant' macro. */
39
40 rtx
41 plus_constant_wide (x, c)
42 register rtx x;
43 register HOST_WIDE_INT c;
44 {
45 register RTX_CODE code;
46 register enum machine_mode mode;
47 register rtx tem;
48 int all_constant = 0;
49
50 if (c == 0)
51 return x;
52
53 restart:
54
55 code = GET_CODE (x);
56 mode = GET_MODE (x);
57 switch (code)
58 {
59 case CONST_INT:
60 return GEN_INT (INTVAL (x) + c);
61
62 case CONST_DOUBLE:
63 {
64 HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
65 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
66 HOST_WIDE_INT l2 = c;
67 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
68 HOST_WIDE_INT lv, hv;
69
70 add_double (l1, h1, l2, h2, &lv, &hv);
71
72 return immed_double_const (lv, hv, VOIDmode);
73 }
74
75 case MEM:
76 /* If this is a reference to the constant pool, try replacing it with
77 a reference to a new constant. If the resulting address isn't
78 valid, don't return it because we have no way to validize it. */
79 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
80 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
81 {
82 /* Any rtl we create here must go in a saveable obstack, since
83 we might have been called from within combine. */
84 push_obstacks_nochange ();
85 rtl_in_saveable_obstack ();
86 tem
87 = force_const_mem (GET_MODE (x),
88 plus_constant (get_pool_constant (XEXP (x, 0)),
89 c));
90 pop_obstacks ();
91 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
92 return tem;
93 }
94 break;
95
96 case CONST:
97 /* If adding to something entirely constant, set a flag
98 so that we can add a CONST around the result. */
99 x = XEXP (x, 0);
100 all_constant = 1;
101 goto restart;
102
103 case SYMBOL_REF:
104 case LABEL_REF:
105 all_constant = 1;
106 break;
107
108 case PLUS:
109 /* The interesting case is adding the integer to a sum.
110 Look for constant term in the sum and combine
111 with C. For an integer constant term, we make a combined
112 integer. For a constant term that is not an explicit integer,
113 we cannot really combine, but group them together anyway.
114
115 Use a recursive call in case the remaining operand is something
116 that we handle specially, such as a SYMBOL_REF. */
117
118 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
119 return plus_constant (XEXP (x, 0), c + INTVAL (XEXP (x, 1)));
120 else if (CONSTANT_P (XEXP (x, 0)))
121 return gen_rtx_PLUS (mode,
122 plus_constant (XEXP (x, 0), c),
123 XEXP (x, 1));
124 else if (CONSTANT_P (XEXP (x, 1)))
125 return gen_rtx_PLUS (mode,
126 XEXP (x, 0),
127 plus_constant (XEXP (x, 1), c));
128 break;
129
130 default:
131 break;
132 }
133
134 if (c != 0)
135 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
136
137 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
138 return x;
139 else if (all_constant)
140 return gen_rtx_CONST (mode, x);
141 else
142 return x;
143 }
144
145 /* This is the same as `plus_constant', except that it handles LO_SUM.
146
147 This function should be used via the `plus_constant_for_output' macro. */
148
149 rtx
150 plus_constant_for_output_wide (x, c)
151 register rtx x;
152 register HOST_WIDE_INT c;
153 {
154 register enum machine_mode mode = GET_MODE (x);
155
156 if (GET_CODE (x) == LO_SUM)
157 return gen_rtx_LO_SUM (mode, XEXP (x, 0),
158 plus_constant_for_output (XEXP (x, 1), c));
159
160 else
161 return plus_constant (x, c);
162 }
163 \f
164 /* If X is a sum, return a new sum like X but lacking any constant terms.
165 Add all the removed constant terms into *CONSTPTR.
166 X itself is not altered. The result != X if and only if
167 it is not isomorphic to X. */
168
169 rtx
170 eliminate_constant_term (x, constptr)
171 rtx x;
172 rtx *constptr;
173 {
174 register rtx x0, x1;
175 rtx tem;
176
177 if (GET_CODE (x) != PLUS)
178 return x;
179
180 /* First handle constants appearing at this level explicitly. */
181 if (GET_CODE (XEXP (x, 1)) == CONST_INT
182 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
183 XEXP (x, 1)))
184 && GET_CODE (tem) == CONST_INT)
185 {
186 *constptr = tem;
187 return eliminate_constant_term (XEXP (x, 0), constptr);
188 }
189
190 tem = const0_rtx;
191 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
192 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
193 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
194 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
195 *constptr, tem))
196 && GET_CODE (tem) == CONST_INT)
197 {
198 *constptr = tem;
199 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
200 }
201
202 return x;
203 }
204
205 /* Returns the insn that next references REG after INSN, or 0
206 if REG is clobbered before next referenced or we cannot find
207 an insn that references REG in a straight-line piece of code. */
208
209 rtx
210 find_next_ref (reg, insn)
211 rtx reg;
212 rtx insn;
213 {
214 rtx next;
215
216 for (insn = NEXT_INSN (insn); insn; insn = next)
217 {
218 next = NEXT_INSN (insn);
219 if (GET_CODE (insn) == NOTE)
220 continue;
221 if (GET_CODE (insn) == CODE_LABEL
222 || GET_CODE (insn) == BARRIER)
223 return 0;
224 if (GET_CODE (insn) == INSN
225 || GET_CODE (insn) == JUMP_INSN
226 || GET_CODE (insn) == CALL_INSN)
227 {
228 if (reg_set_p (reg, insn))
229 return 0;
230 if (reg_mentioned_p (reg, PATTERN (insn)))
231 return insn;
232 if (GET_CODE (insn) == JUMP_INSN)
233 {
234 if (simplejump_p (insn))
235 next = JUMP_LABEL (insn);
236 else
237 return 0;
238 }
239 if (GET_CODE (insn) == CALL_INSN
240 && REGNO (reg) < FIRST_PSEUDO_REGISTER
241 && call_used_regs[REGNO (reg)])
242 return 0;
243 }
244 else
245 abort ();
246 }
247 return 0;
248 }
249
250 /* Return an rtx for the size in bytes of the value of EXP. */
251
252 rtx
253 expr_size (exp)
254 tree exp;
255 {
256 tree size = size_in_bytes (TREE_TYPE (exp));
257
258 if (TREE_CODE (size) != INTEGER_CST
259 && contains_placeholder_p (size))
260 size = build (WITH_RECORD_EXPR, sizetype, size, exp);
261
262 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype),
263 EXPAND_MEMORY_USE_BAD);
264 }
265 \f
266 /* Return a copy of X in which all memory references
267 and all constants that involve symbol refs
268 have been replaced with new temporary registers.
269 Also emit code to load the memory locations and constants
270 into those registers.
271
272 If X contains no such constants or memory references,
273 X itself (not a copy) is returned.
274
275 If a constant is found in the address that is not a legitimate constant
276 in an insn, it is left alone in the hope that it might be valid in the
277 address.
278
279 X may contain no arithmetic except addition, subtraction and multiplication.
280 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
281
282 static rtx
283 break_out_memory_refs (x)
284 register rtx x;
285 {
286 if (GET_CODE (x) == MEM
287 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
288 && GET_MODE (x) != VOIDmode))
289 x = force_reg (GET_MODE (x), x);
290 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
291 || GET_CODE (x) == MULT)
292 {
293 register rtx op0 = break_out_memory_refs (XEXP (x, 0));
294 register rtx op1 = break_out_memory_refs (XEXP (x, 1));
295
296 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
297 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
298 }
299
300 return x;
301 }
302
303 #ifdef POINTERS_EXTEND_UNSIGNED
304
305 /* Given X, a memory address in ptr_mode, convert it to an address
306 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
307 the fact that pointers are not allowed to overflow by commuting arithmetic
308 operations over conversions so that address arithmetic insns can be
309 used. */
310
311 rtx
312 convert_memory_address (to_mode, x)
313 enum machine_mode to_mode;
314 rtx x;
315 {
316 enum machine_mode from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
317 rtx temp;
318
319 /* Here we handle some special cases. If none of them apply, fall through
320 to the default case. */
321 switch (GET_CODE (x))
322 {
323 case CONST_INT:
324 case CONST_DOUBLE:
325 return x;
326
327 case LABEL_REF:
328 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
329 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
330 return temp;
331
332 case SYMBOL_REF:
333 temp = gen_rtx_SYMBOL_REF (to_mode, XSTR (x, 0));
334 SYMBOL_REF_FLAG (temp) = SYMBOL_REF_FLAG (x);
335 CONSTANT_POOL_ADDRESS_P (temp) = CONSTANT_POOL_ADDRESS_P (x);
336 return temp;
337
338 case CONST:
339 return gen_rtx_CONST (to_mode,
340 convert_memory_address (to_mode, XEXP (x, 0)));
341
342 case PLUS:
343 case MULT:
344 /* For addition the second operand is a small constant, we can safely
345 permute the conversion and addition operation. We can always safely
346 permute them if we are making the address narrower. In addition,
347 always permute the operations if this is a constant. */
348 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
349 || (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 1)) == CONST_INT
350 && (INTVAL (XEXP (x, 1)) + 20000 < 40000
351 || CONSTANT_P (XEXP (x, 0)))))
352 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
353 convert_memory_address (to_mode, XEXP (x, 0)),
354 convert_memory_address (to_mode, XEXP (x, 1)));
355 break;
356
357 default:
358 break;
359 }
360
361 return convert_modes (to_mode, from_mode,
362 x, POINTERS_EXTEND_UNSIGNED);
363 }
364 #endif
365
366 /* Given a memory address or facsimile X, construct a new address,
367 currently equivalent, that is stable: future stores won't change it.
368
369 X must be composed of constants, register and memory references
370 combined with addition, subtraction and multiplication:
371 in other words, just what you can get from expand_expr if sum_ok is 1.
372
373 Works by making copies of all regs and memory locations used
374 by X and combining them the same way X does.
375 You could also stabilize the reference to this address
376 by copying the address to a register with copy_to_reg;
377 but then you wouldn't get indexed addressing in the reference. */
378
379 rtx
380 copy_all_regs (x)
381 register rtx x;
382 {
383 if (GET_CODE (x) == REG)
384 {
385 if (REGNO (x) != FRAME_POINTER_REGNUM
386 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
387 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
388 #endif
389 )
390 x = copy_to_reg (x);
391 }
392 else if (GET_CODE (x) == MEM)
393 x = copy_to_reg (x);
394 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
395 || GET_CODE (x) == MULT)
396 {
397 register rtx op0 = copy_all_regs (XEXP (x, 0));
398 register rtx op1 = copy_all_regs (XEXP (x, 1));
399 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
400 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
401 }
402 return x;
403 }
404 \f
405 /* Return something equivalent to X but valid as a memory address
406 for something of mode MODE. When X is not itself valid, this
407 works by copying X or subexpressions of it into registers. */
408
409 rtx
410 memory_address (mode, x)
411 enum machine_mode mode;
412 register rtx x;
413 {
414 register rtx oldx = x;
415
416 if (GET_CODE (x) == ADDRESSOF)
417 return x;
418
419 #ifdef POINTERS_EXTEND_UNSIGNED
420 if (GET_MODE (x) == ptr_mode)
421 x = convert_memory_address (Pmode, x);
422 #endif
423
424 /* By passing constant addresses thru registers
425 we get a chance to cse them. */
426 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
427 x = force_reg (Pmode, x);
428
429 /* Accept a QUEUED that refers to a REG
430 even though that isn't a valid address.
431 On attempting to put this in an insn we will call protect_from_queue
432 which will turn it into a REG, which is valid. */
433 else if (GET_CODE (x) == QUEUED
434 && GET_CODE (QUEUED_VAR (x)) == REG)
435 ;
436
437 /* We get better cse by rejecting indirect addressing at this stage.
438 Let the combiner create indirect addresses where appropriate.
439 For now, generate the code so that the subexpressions useful to share
440 are visible. But not if cse won't be done! */
441 else
442 {
443 if (! cse_not_expected && GET_CODE (x) != REG)
444 x = break_out_memory_refs (x);
445
446 /* At this point, any valid address is accepted. */
447 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
448
449 /* If it was valid before but breaking out memory refs invalidated it,
450 use it the old way. */
451 if (memory_address_p (mode, oldx))
452 goto win2;
453
454 /* Perform machine-dependent transformations on X
455 in certain cases. This is not necessary since the code
456 below can handle all possible cases, but machine-dependent
457 transformations can make better code. */
458 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
459
460 /* PLUS and MULT can appear in special ways
461 as the result of attempts to make an address usable for indexing.
462 Usually they are dealt with by calling force_operand, below.
463 But a sum containing constant terms is special
464 if removing them makes the sum a valid address:
465 then we generate that address in a register
466 and index off of it. We do this because it often makes
467 shorter code, and because the addresses thus generated
468 in registers often become common subexpressions. */
469 if (GET_CODE (x) == PLUS)
470 {
471 rtx constant_term = const0_rtx;
472 rtx y = eliminate_constant_term (x, &constant_term);
473 if (constant_term == const0_rtx
474 || ! memory_address_p (mode, y))
475 x = force_operand (x, NULL_RTX);
476 else
477 {
478 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
479 if (! memory_address_p (mode, y))
480 x = force_operand (x, NULL_RTX);
481 else
482 x = y;
483 }
484 }
485
486 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
487 x = force_operand (x, NULL_RTX);
488
489 /* If we have a register that's an invalid address,
490 it must be a hard reg of the wrong class. Copy it to a pseudo. */
491 else if (GET_CODE (x) == REG)
492 x = copy_to_reg (x);
493
494 /* Last resort: copy the value to a register, since
495 the register is a valid address. */
496 else
497 x = force_reg (Pmode, x);
498
499 goto done;
500
501 win2:
502 x = oldx;
503 win:
504 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG
505 /* Don't copy an addr via a reg if it is one of our stack slots. */
506 && ! (GET_CODE (x) == PLUS
507 && (XEXP (x, 0) == virtual_stack_vars_rtx
508 || XEXP (x, 0) == virtual_incoming_args_rtx)))
509 {
510 if (general_operand (x, Pmode))
511 x = force_reg (Pmode, x);
512 else
513 x = force_operand (x, NULL_RTX);
514 }
515 }
516
517 done:
518
519 /* If we didn't change the address, we are done. Otherwise, mark
520 a reg as a pointer if we have REG or REG + CONST_INT. */
521 if (oldx == x)
522 return x;
523 else if (GET_CODE (x) == REG)
524 mark_reg_pointer (x, 1);
525 else if (GET_CODE (x) == PLUS
526 && GET_CODE (XEXP (x, 0)) == REG
527 && GET_CODE (XEXP (x, 1)) == CONST_INT)
528 mark_reg_pointer (XEXP (x, 0), 1);
529
530 /* OLDX may have been the address on a temporary. Update the address
531 to indicate that X is now used. */
532 update_temp_slot_address (oldx, x);
533
534 return x;
535 }
536
537 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
538
539 rtx
540 memory_address_noforce (mode, x)
541 enum machine_mode mode;
542 rtx x;
543 {
544 int ambient_force_addr = flag_force_addr;
545 rtx val;
546
547 flag_force_addr = 0;
548 val = memory_address (mode, x);
549 flag_force_addr = ambient_force_addr;
550 return val;
551 }
552
553 /* Convert a mem ref into one with a valid memory address.
554 Pass through anything else unchanged. */
555
556 rtx
557 validize_mem (ref)
558 rtx ref;
559 {
560 if (GET_CODE (ref) != MEM)
561 return ref;
562 if (memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
563 return ref;
564 /* Don't alter REF itself, since that is probably a stack slot. */
565 return change_address (ref, GET_MODE (ref), XEXP (ref, 0));
566 }
567 \f
568 /* Return a modified copy of X with its memory address copied
569 into a temporary register to protect it from side effects.
570 If X is not a MEM, it is returned unchanged (and not copied).
571 Perhaps even if it is a MEM, if there is no need to change it. */
572
573 rtx
574 stabilize (x)
575 rtx x;
576 {
577 register rtx addr;
578 if (GET_CODE (x) != MEM)
579 return x;
580 addr = XEXP (x, 0);
581 if (rtx_unstable_p (addr))
582 {
583 rtx temp = copy_all_regs (addr);
584 rtx mem;
585 if (GET_CODE (temp) != REG)
586 temp = copy_to_reg (temp);
587 mem = gen_rtx_MEM (GET_MODE (x), temp);
588
589 /* Mark returned memref with in_struct if it's in an array or
590 structure. Copy const and volatile from original memref. */
591
592 MEM_IN_STRUCT_P (mem) = MEM_IN_STRUCT_P (x) || GET_CODE (addr) == PLUS;
593 RTX_UNCHANGING_P (mem) = RTX_UNCHANGING_P (x);
594 MEM_VOLATILE_P (mem) = MEM_VOLATILE_P (x);
595 return mem;
596 }
597 return x;
598 }
599 \f
600 /* Copy the value or contents of X to a new temp reg and return that reg. */
601
602 rtx
603 copy_to_reg (x)
604 rtx x;
605 {
606 register rtx temp = gen_reg_rtx (GET_MODE (x));
607
608 /* If not an operand, must be an address with PLUS and MULT so
609 do the computation. */
610 if (! general_operand (x, VOIDmode))
611 x = force_operand (x, temp);
612
613 if (x != temp)
614 emit_move_insn (temp, x);
615
616 return temp;
617 }
618
619 /* Like copy_to_reg but always give the new register mode Pmode
620 in case X is a constant. */
621
622 rtx
623 copy_addr_to_reg (x)
624 rtx x;
625 {
626 return copy_to_mode_reg (Pmode, x);
627 }
628
629 /* Like copy_to_reg but always give the new register mode MODE
630 in case X is a constant. */
631
632 rtx
633 copy_to_mode_reg (mode, x)
634 enum machine_mode mode;
635 rtx x;
636 {
637 register rtx temp = gen_reg_rtx (mode);
638
639 /* If not an operand, must be an address with PLUS and MULT so
640 do the computation. */
641 if (! general_operand (x, VOIDmode))
642 x = force_operand (x, temp);
643
644 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
645 abort ();
646 if (x != temp)
647 emit_move_insn (temp, x);
648 return temp;
649 }
650
651 /* Load X into a register if it is not already one.
652 Use mode MODE for the register.
653 X should be valid for mode MODE, but it may be a constant which
654 is valid for all integer modes; that's why caller must specify MODE.
655
656 The caller must not alter the value in the register we return,
657 since we mark it as a "constant" register. */
658
659 rtx
660 force_reg (mode, x)
661 enum machine_mode mode;
662 rtx x;
663 {
664 register rtx temp, insn, set;
665
666 if (GET_CODE (x) == REG)
667 return x;
668 temp = gen_reg_rtx (mode);
669 insn = emit_move_insn (temp, x);
670
671 /* Let optimizers know that TEMP's value never changes
672 and that X can be substituted for it. Don't get confused
673 if INSN set something else (such as a SUBREG of TEMP). */
674 if (CONSTANT_P (x)
675 && (set = single_set (insn)) != 0
676 && SET_DEST (set) == temp)
677 {
678 rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
679
680 if (note)
681 XEXP (note, 0) = x;
682 else
683 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EQUAL, x, REG_NOTES (insn));
684 }
685 return temp;
686 }
687
688 /* If X is a memory ref, copy its contents to a new temp reg and return
689 that reg. Otherwise, return X. */
690
691 rtx
692 force_not_mem (x)
693 rtx x;
694 {
695 register rtx temp;
696 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode)
697 return x;
698 temp = gen_reg_rtx (GET_MODE (x));
699 emit_move_insn (temp, x);
700 return temp;
701 }
702
703 /* Copy X to TARGET (if it's nonzero and a reg)
704 or to a new temp reg and return that reg.
705 MODE is the mode to use for X in case it is a constant. */
706
707 rtx
708 copy_to_suggested_reg (x, target, mode)
709 rtx x, target;
710 enum machine_mode mode;
711 {
712 register rtx temp;
713
714 if (target && GET_CODE (target) == REG)
715 temp = target;
716 else
717 temp = gen_reg_rtx (mode);
718
719 emit_move_insn (temp, x);
720 return temp;
721 }
722 \f
723 /* Return the mode to use to store a scalar of TYPE and MODE.
724 PUNSIGNEDP points to the signedness of the type and may be adjusted
725 to show what signedness to use on extension operations.
726
727 FOR_CALL is non-zero if this call is promoting args for a call. */
728
729 enum machine_mode
730 promote_mode (type, mode, punsignedp, for_call)
731 tree type;
732 enum machine_mode mode;
733 int *punsignedp;
734 int for_call;
735 {
736 enum tree_code code = TREE_CODE (type);
737 int unsignedp = *punsignedp;
738
739 #ifdef PROMOTE_FOR_CALL_ONLY
740 if (! for_call)
741 return mode;
742 #endif
743
744 switch (code)
745 {
746 #ifdef PROMOTE_MODE
747 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
748 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
749 PROMOTE_MODE (mode, unsignedp, type);
750 break;
751 #endif
752
753 #ifdef POINTERS_EXTEND_UNSIGNED
754 case REFERENCE_TYPE:
755 case POINTER_TYPE:
756 mode = Pmode;
757 unsignedp = POINTERS_EXTEND_UNSIGNED;
758 break;
759 #endif
760
761 default:
762 break;
763 }
764
765 *punsignedp = unsignedp;
766 return mode;
767 }
768 \f
769 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
770 This pops when ADJUST is positive. ADJUST need not be constant. */
771
772 void
773 adjust_stack (adjust)
774 rtx adjust;
775 {
776 rtx temp;
777 adjust = protect_from_queue (adjust, 0);
778
779 if (adjust == const0_rtx)
780 return;
781
782 temp = expand_binop (Pmode,
783 #ifdef STACK_GROWS_DOWNWARD
784 add_optab,
785 #else
786 sub_optab,
787 #endif
788 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
789 OPTAB_LIB_WIDEN);
790
791 if (temp != stack_pointer_rtx)
792 emit_move_insn (stack_pointer_rtx, temp);
793 }
794
795 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
796 This pushes when ADJUST is positive. ADJUST need not be constant. */
797
798 void
799 anti_adjust_stack (adjust)
800 rtx adjust;
801 {
802 rtx temp;
803 adjust = protect_from_queue (adjust, 0);
804
805 if (adjust == const0_rtx)
806 return;
807
808 temp = expand_binop (Pmode,
809 #ifdef STACK_GROWS_DOWNWARD
810 sub_optab,
811 #else
812 add_optab,
813 #endif
814 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
815 OPTAB_LIB_WIDEN);
816
817 if (temp != stack_pointer_rtx)
818 emit_move_insn (stack_pointer_rtx, temp);
819 }
820
821 /* Round the size of a block to be pushed up to the boundary required
822 by this machine. SIZE is the desired size, which need not be constant. */
823
824 rtx
825 round_push (size)
826 rtx size;
827 {
828 #ifdef STACK_BOUNDARY
829 int align = STACK_BOUNDARY / BITS_PER_UNIT;
830 if (align == 1)
831 return size;
832 if (GET_CODE (size) == CONST_INT)
833 {
834 int new = (INTVAL (size) + align - 1) / align * align;
835 if (INTVAL (size) != new)
836 size = GEN_INT (new);
837 }
838 else
839 {
840 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
841 but we know it can't. So add ourselves and then do
842 TRUNC_DIV_EXPR. */
843 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
844 NULL_RTX, 1, OPTAB_LIB_WIDEN);
845 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
846 NULL_RTX, 1);
847 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
848 }
849 #endif /* STACK_BOUNDARY */
850 return size;
851 }
852 \f
853 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
854 to a previously-created save area. If no save area has been allocated,
855 this function will allocate one. If a save area is specified, it
856 must be of the proper mode.
857
858 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
859 are emitted at the current position. */
860
861 void
862 emit_stack_save (save_level, psave, after)
863 enum save_level save_level;
864 rtx *psave;
865 rtx after;
866 {
867 rtx sa = *psave;
868 /* The default is that we use a move insn and save in a Pmode object. */
869 rtx (*fcn) () = gen_move_insn;
870 enum machine_mode mode = Pmode;
871
872 /* See if this machine has anything special to do for this kind of save. */
873 switch (save_level)
874 {
875 #ifdef HAVE_save_stack_block
876 case SAVE_BLOCK:
877 if (HAVE_save_stack_block)
878 {
879 fcn = gen_save_stack_block;
880 mode = insn_operand_mode[CODE_FOR_save_stack_block][0];
881 }
882 break;
883 #endif
884 #ifdef HAVE_save_stack_function
885 case SAVE_FUNCTION:
886 if (HAVE_save_stack_function)
887 {
888 fcn = gen_save_stack_function;
889 mode = insn_operand_mode[CODE_FOR_save_stack_function][0];
890 }
891 break;
892 #endif
893 #ifdef HAVE_save_stack_nonlocal
894 case SAVE_NONLOCAL:
895 if (HAVE_save_stack_nonlocal)
896 {
897 fcn = gen_save_stack_nonlocal;
898 mode = insn_operand_mode[(int) CODE_FOR_save_stack_nonlocal][0];
899 }
900 break;
901 #endif
902 default:
903 break;
904 }
905
906 /* If there is no save area and we have to allocate one, do so. Otherwise
907 verify the save area is the proper mode. */
908
909 if (sa == 0)
910 {
911 if (mode != VOIDmode)
912 {
913 if (save_level == SAVE_NONLOCAL)
914 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
915 else
916 *psave = sa = gen_reg_rtx (mode);
917 }
918 }
919 else
920 {
921 if (mode == VOIDmode || GET_MODE (sa) != mode)
922 abort ();
923 }
924
925 if (after)
926 {
927 rtx seq;
928
929 start_sequence ();
930 /* We must validize inside the sequence, to ensure that any instructions
931 created by the validize call also get moved to the right place. */
932 if (sa != 0)
933 sa = validize_mem (sa);
934 emit_insn (fcn (sa, stack_pointer_rtx));
935 seq = gen_sequence ();
936 end_sequence ();
937 emit_insn_after (seq, after);
938 }
939 else
940 {
941 if (sa != 0)
942 sa = validize_mem (sa);
943 emit_insn (fcn (sa, stack_pointer_rtx));
944 }
945 }
946
947 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
948 area made by emit_stack_save. If it is zero, we have nothing to do.
949
950 Put any emitted insns after insn AFTER, if nonzero, otherwise at
951 current position. */
952
953 void
954 emit_stack_restore (save_level, sa, after)
955 enum save_level save_level;
956 rtx after;
957 rtx sa;
958 {
959 /* The default is that we use a move insn. */
960 rtx (*fcn) () = gen_move_insn;
961
962 /* See if this machine has anything special to do for this kind of save. */
963 switch (save_level)
964 {
965 #ifdef HAVE_restore_stack_block
966 case SAVE_BLOCK:
967 if (HAVE_restore_stack_block)
968 fcn = gen_restore_stack_block;
969 break;
970 #endif
971 #ifdef HAVE_restore_stack_function
972 case SAVE_FUNCTION:
973 if (HAVE_restore_stack_function)
974 fcn = gen_restore_stack_function;
975 break;
976 #endif
977 #ifdef HAVE_restore_stack_nonlocal
978
979 case SAVE_NONLOCAL:
980 if (HAVE_restore_stack_nonlocal)
981 fcn = gen_restore_stack_nonlocal;
982 break;
983 #endif
984 default:
985 break;
986 }
987
988 if (sa != 0)
989 sa = validize_mem (sa);
990
991 if (after)
992 {
993 rtx seq;
994
995 start_sequence ();
996 emit_insn (fcn (stack_pointer_rtx, sa));
997 seq = gen_sequence ();
998 end_sequence ();
999 emit_insn_after (seq, after);
1000 }
1001 else
1002 emit_insn (fcn (stack_pointer_rtx, sa));
1003 }
1004 \f
1005 #ifdef SETJMP_VIA_SAVE_AREA
1006 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1007 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1008 platforms, the dynamic stack space used can corrupt the original
1009 frame, thus causing a crash if a longjmp unwinds to it. */
1010
1011 void
1012 optimize_save_area_alloca (insns)
1013 rtx insns;
1014 {
1015 rtx insn;
1016
1017 for (insn = insns; insn; insn = NEXT_INSN(insn))
1018 {
1019 rtx note;
1020
1021 if (GET_CODE (insn) != INSN)
1022 continue;
1023
1024 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1025 {
1026 if (REG_NOTE_KIND (note) != REG_SAVE_AREA)
1027 continue;
1028
1029 if (!current_function_calls_setjmp)
1030 {
1031 rtx pat = PATTERN (insn);
1032
1033 /* If we do not see the note in a pattern matching
1034 these precise characteristics, we did something
1035 entirely wrong in allocate_dynamic_stack_space.
1036
1037 Note, one way this could happen if if SETJMP_VIA_SAVE_AREA
1038 was defined on a machine where stacks grow towards higher
1039 addresses.
1040
1041 Right now only supported port with stack that grow upward
1042 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1043 if (GET_CODE (pat) != SET
1044 || SET_DEST (pat) != stack_pointer_rtx
1045 || GET_CODE (SET_SRC (pat)) != MINUS
1046 || XEXP (SET_SRC (pat), 0) != stack_pointer_rtx)
1047 abort ();
1048
1049 /* This will now be transformed into a (set REG REG)
1050 so we can just blow away all the other notes. */
1051 XEXP (SET_SRC (pat), 1) = XEXP (note, 0);
1052 REG_NOTES (insn) = NULL_RTX;
1053 }
1054 else
1055 {
1056 /* setjmp was called, we must remove the REG_SAVE_AREA
1057 note so that later passes do not get confused by its
1058 presence. */
1059 if (note == REG_NOTES (insn))
1060 {
1061 REG_NOTES (insn) = XEXP (note, 1);
1062 }
1063 else
1064 {
1065 rtx srch;
1066
1067 for (srch = REG_NOTES (insn); srch; srch = XEXP (srch, 1))
1068 if (XEXP (srch, 1) == note)
1069 break;
1070
1071 if (srch == NULL_RTX)
1072 abort();
1073
1074 XEXP (srch, 1) = XEXP (note, 1);
1075 }
1076 }
1077 /* Once we've seen the note of interest, we need not look at
1078 the rest of them. */
1079 break;
1080 }
1081 }
1082 }
1083 #endif /* SETJMP_VIA_SAVE_AREA */
1084
1085 /* Return an rtx representing the address of an area of memory dynamically
1086 pushed on the stack. This region of memory is always aligned to
1087 a multiple of BIGGEST_ALIGNMENT.
1088
1089 Any required stack pointer alignment is preserved.
1090
1091 SIZE is an rtx representing the size of the area.
1092 TARGET is a place in which the address can be placed.
1093
1094 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1095
1096 rtx
1097 allocate_dynamic_stack_space (size, target, known_align)
1098 rtx size;
1099 rtx target;
1100 int known_align;
1101 {
1102 #ifdef SETJMP_VIA_SAVE_AREA
1103 rtx setjmpless_size = NULL_RTX;
1104 #endif
1105
1106 /* If we're asking for zero bytes, it doesn't matter what we point
1107 to since we can't dereference it. But return a reasonable
1108 address anyway. */
1109 if (size == const0_rtx)
1110 return virtual_stack_dynamic_rtx;
1111
1112 /* Otherwise, show we're calling alloca or equivalent. */
1113 current_function_calls_alloca = 1;
1114
1115 /* Ensure the size is in the proper mode. */
1116 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1117 size = convert_to_mode (Pmode, size, 1);
1118
1119 /* We will need to ensure that the address we return is aligned to
1120 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1121 always know its final value at this point in the compilation (it
1122 might depend on the size of the outgoing parameter lists, for
1123 example), so we must align the value to be returned in that case.
1124 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if
1125 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1126 We must also do an alignment operation on the returned value if
1127 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1128
1129 If we have to align, we must leave space in SIZE for the hole
1130 that might result from the alignment operation. */
1131
1132 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) || ! defined (STACK_BOUNDARY)
1133 #define MUST_ALIGN 1
1134 #else
1135 #define MUST_ALIGN (STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1136 #endif
1137
1138 if (MUST_ALIGN)
1139 {
1140 if (GET_CODE (size) == CONST_INT)
1141 size = GEN_INT (INTVAL (size)
1142 + (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1));
1143 else
1144 size = expand_binop (Pmode, add_optab, size,
1145 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1146 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1147 }
1148
1149 #ifdef SETJMP_VIA_SAVE_AREA
1150 /* If setjmp restores regs from a save area in the stack frame,
1151 avoid clobbering the reg save area. Note that the offset of
1152 virtual_incoming_args_rtx includes the preallocated stack args space.
1153 It would be no problem to clobber that, but it's on the wrong side
1154 of the old save area. */
1155 {
1156 rtx dynamic_offset
1157 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1158 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1159
1160 if (!current_function_calls_setjmp)
1161 {
1162 int align = STACK_BOUNDARY / BITS_PER_UNIT;
1163
1164 /* See optimize_save_area_alloca to understand what is being
1165 set up here. */
1166
1167 #if !defined(STACK_BOUNDARY) || !defined(MUST_ALIGN) || (STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1168 /* If anyone creates a target with these characteristics, let them
1169 know that our optimization cannot work correctly in such a case. */
1170 abort();
1171 #endif
1172
1173 if (GET_CODE (size) == CONST_INT)
1174 {
1175 int new = INTVAL (size) / align * align;
1176
1177 if (INTVAL (size) != new)
1178 setjmpless_size = GEN_INT (new);
1179 else
1180 setjmpless_size = size;
1181 }
1182 else
1183 {
1184 /* Since we know overflow is not possible, we avoid using
1185 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1186 setjmpless_size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1187 GEN_INT (align), NULL_RTX, 1);
1188 setjmpless_size = expand_mult (Pmode, setjmpless_size,
1189 GEN_INT (align), NULL_RTX, 1);
1190 }
1191 /* Our optimization works based upon being able to perform a simple
1192 transformation of this RTL into a (set REG REG) so make sure things
1193 did in fact end up in a REG. */
1194 if (!arith_operand (setjmpless_size, Pmode))
1195 setjmpless_size = force_reg (Pmode, setjmpless_size);
1196 }
1197
1198 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1199 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1200 }
1201 #endif /* SETJMP_VIA_SAVE_AREA */
1202
1203 /* Round the size to a multiple of the required stack alignment.
1204 Since the stack if presumed to be rounded before this allocation,
1205 this will maintain the required alignment.
1206
1207 If the stack grows downward, we could save an insn by subtracting
1208 SIZE from the stack pointer and then aligning the stack pointer.
1209 The problem with this is that the stack pointer may be unaligned
1210 between the execution of the subtraction and alignment insns and
1211 some machines do not allow this. Even on those that do, some
1212 signal handlers malfunction if a signal should occur between those
1213 insns. Since this is an extremely rare event, we have no reliable
1214 way of knowing which systems have this problem. So we avoid even
1215 momentarily mis-aligning the stack. */
1216
1217 #ifdef STACK_BOUNDARY
1218 /* If we added a variable amount to SIZE,
1219 we can no longer assume it is aligned. */
1220 #if !defined (SETJMP_VIA_SAVE_AREA)
1221 if (MUST_ALIGN || known_align % STACK_BOUNDARY != 0)
1222 #endif
1223 size = round_push (size);
1224 #endif
1225
1226 do_pending_stack_adjust ();
1227
1228 /* If needed, check that we have the required amount of stack. Take into
1229 account what has already been checked. */
1230 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1231 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1232
1233 /* Don't use a TARGET that isn't a pseudo. */
1234 if (target == 0 || GET_CODE (target) != REG
1235 || REGNO (target) < FIRST_PSEUDO_REGISTER)
1236 target = gen_reg_rtx (Pmode);
1237
1238 mark_reg_pointer (target, known_align / BITS_PER_UNIT);
1239
1240 /* Perform the required allocation from the stack. Some systems do
1241 this differently than simply incrementing/decrementing from the
1242 stack pointer, such as acquiring the space by calling malloc(). */
1243 #ifdef HAVE_allocate_stack
1244 if (HAVE_allocate_stack)
1245 {
1246 enum machine_mode mode;
1247
1248 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][0]
1249 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][0])
1250 (target, Pmode)))
1251 target = copy_to_mode_reg (Pmode, target);
1252 mode = insn_operand_mode[(int) CODE_FOR_allocate_stack][1];
1253 size = convert_modes (mode, ptr_mode, size, 1);
1254 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][1]
1255 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][1])
1256 (size, mode)))
1257 size = copy_to_mode_reg (mode, size);
1258
1259 emit_insn (gen_allocate_stack (target, size));
1260 }
1261 else
1262 #endif
1263 {
1264 #ifndef STACK_GROWS_DOWNWARD
1265 emit_move_insn (target, virtual_stack_dynamic_rtx);
1266 #endif
1267 size = convert_modes (Pmode, ptr_mode, size, 1);
1268 anti_adjust_stack (size);
1269 #ifdef SETJMP_VIA_SAVE_AREA
1270 if (setjmpless_size != NULL_RTX)
1271 {
1272 rtx note_target = get_last_insn ();
1273
1274 REG_NOTES (note_target) = gen_rtx (EXPR_LIST, REG_SAVE_AREA,
1275 setjmpless_size,
1276 REG_NOTES (note_target));
1277 }
1278 #endif /* SETJMP_VIA_SAVE_AREA */
1279 #ifdef STACK_GROWS_DOWNWARD
1280 emit_move_insn (target, virtual_stack_dynamic_rtx);
1281 #endif
1282 }
1283
1284 if (MUST_ALIGN)
1285 {
1286 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1287 but we know it can't. So add ourselves and then do
1288 TRUNC_DIV_EXPR. */
1289 target = expand_binop (Pmode, add_optab, target,
1290 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1291 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1292 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1293 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1294 NULL_RTX, 1);
1295 target = expand_mult (Pmode, target,
1296 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1297 NULL_RTX, 1);
1298 }
1299
1300 /* Some systems require a particular insn to refer to the stack
1301 to make the pages exist. */
1302 #ifdef HAVE_probe
1303 if (HAVE_probe)
1304 emit_insn (gen_probe ());
1305 #endif
1306
1307 /* Record the new stack level for nonlocal gotos. */
1308 if (nonlocal_goto_handler_slot != 0)
1309 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
1310
1311 return target;
1312 }
1313 \f
1314 /* Emit one stack probe at ADDRESS, an address within the stack. */
1315
1316 static void
1317 emit_stack_probe (address)
1318 rtx address;
1319 {
1320 rtx memref = gen_rtx_MEM (word_mode, address);
1321
1322 MEM_VOLATILE_P (memref) = 1;
1323
1324 if (STACK_CHECK_PROBE_LOAD)
1325 emit_move_insn (gen_reg_rtx (word_mode), memref);
1326 else
1327 emit_move_insn (memref, const0_rtx);
1328 }
1329
1330 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1331 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1332 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1333 subtract from the stack. If SIZE is constant, this is done
1334 with a fixed number of probes. Otherwise, we must make a loop. */
1335
1336 #ifdef STACK_GROWS_DOWNWARD
1337 #define STACK_GROW_OP MINUS
1338 #else
1339 #define STACK_GROW_OP PLUS
1340 #endif
1341
1342 void
1343 probe_stack_range (first, size)
1344 HOST_WIDE_INT first;
1345 rtx size;
1346 {
1347 /* First see if we have an insn to check the stack. Use it if so. */
1348 #ifdef HAVE_check_stack
1349 if (HAVE_check_stack)
1350 {
1351 rtx last_addr
1352 = force_operand (gen_rtx_STACK_GROW_OP (Pmode,
1353 stack_pointer_rtx,
1354 plus_constant (size, first)),
1355 NULL_RTX);
1356
1357 if (insn_operand_predicate[(int) CODE_FOR_check_stack][0]
1358 && ! ((*insn_operand_predicate[(int) CODE_FOR_check_stack][0])
1359 (last_address, Pmode)))
1360 last_address = copy_to_mode_reg (Pmode, last_address);
1361
1362 emit_insn (gen_check_stack (last_address));
1363 return;
1364 }
1365 #endif
1366
1367 /* If we have to generate explicit probes, see if we have a constant
1368 small number of them to generate. If so, that's the easy case. */
1369 if (GET_CODE (size) == CONST_INT && INTVAL (size) < 10)
1370 {
1371 HOST_WIDE_INT offset;
1372
1373 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1374 for values of N from 1 until it exceeds LAST. If only one
1375 probe is needed, this will not generate any code. Then probe
1376 at LAST. */
1377 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1378 offset < INTVAL (size);
1379 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1380 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1381 stack_pointer_rtx,
1382 GEN_INT (offset)));
1383
1384 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1385 stack_pointer_rtx,
1386 plus_constant (size, first)));
1387 }
1388
1389 /* In the variable case, do the same as above, but in a loop. We emit loop
1390 notes so that loop optimization can be done. */
1391 else
1392 {
1393 rtx test_addr
1394 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1395 stack_pointer_rtx,
1396 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1397 NULL_RTX);
1398 rtx last_addr
1399 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1400 stack_pointer_rtx,
1401 plus_constant (size, first)),
1402 NULL_RTX);
1403 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1404 rtx loop_lab = gen_label_rtx ();
1405 rtx test_lab = gen_label_rtx ();
1406 rtx end_lab = gen_label_rtx ();
1407 rtx temp;
1408
1409 if (GET_CODE (test_addr) != REG
1410 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1411 test_addr = force_reg (Pmode, test_addr);
1412
1413 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
1414 emit_jump (test_lab);
1415
1416 emit_label (loop_lab);
1417 emit_stack_probe (test_addr);
1418
1419 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
1420
1421 #ifdef STACK_GROWS_DOWNWARD
1422 #define CMP_OPCODE GTU
1423 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1424 1, OPTAB_WIDEN);
1425 #else
1426 #define CMP_OPCODE LTU
1427 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1428 1, OPTAB_WIDEN);
1429 #endif
1430
1431 if (temp != test_addr)
1432 abort ();
1433
1434 emit_label (test_lab);
1435 emit_cmp_insn (test_addr, last_addr, CMP_OPCODE, NULL_RTX, Pmode, 1, 0);
1436 emit_jump_insn ((*bcc_gen_fctn[(int) CMP_OPCODE]) (loop_lab));
1437 emit_jump (end_lab);
1438 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
1439 emit_label (end_lab);
1440
1441 /* If will be doing stupid optimization, show test_addr is still live. */
1442 if (obey_regdecls)
1443 emit_insn (gen_rtx_USE (VOIDmode, test_addr));
1444
1445 emit_stack_probe (last_addr);
1446 }
1447 }
1448 \f
1449 /* Return an rtx representing the register or memory location
1450 in which a scalar value of data type VALTYPE
1451 was returned by a function call to function FUNC.
1452 FUNC is a FUNCTION_DECL node if the precise function is known,
1453 otherwise 0. */
1454
1455 rtx
1456 hard_function_value (valtype, func)
1457 tree valtype;
1458 tree func;
1459 {
1460 rtx val = FUNCTION_VALUE (valtype, func);
1461 if (GET_CODE (val) == REG
1462 && GET_MODE (val) == BLKmode)
1463 {
1464 int bytes = int_size_in_bytes (valtype);
1465 enum machine_mode tmpmode;
1466 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1467 tmpmode != MAX_MACHINE_MODE;
1468 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1469 {
1470 /* Have we found a large enough mode? */
1471 if (GET_MODE_SIZE (tmpmode) >= bytes)
1472 break;
1473 }
1474
1475 /* No suitable mode found. */
1476 if (tmpmode == MAX_MACHINE_MODE)
1477 abort ();
1478
1479 PUT_MODE (val, tmpmode);
1480 }
1481 return val;
1482 }
1483
1484 /* Return an rtx representing the register or memory location
1485 in which a scalar value of mode MODE was returned by a library call. */
1486
1487 rtx
1488 hard_libcall_value (mode)
1489 enum machine_mode mode;
1490 {
1491 return LIBCALL_VALUE (mode);
1492 }
1493
1494 /* Look up the tree code for a given rtx code
1495 to provide the arithmetic operation for REAL_ARITHMETIC.
1496 The function returns an int because the caller may not know
1497 what `enum tree_code' means. */
1498
1499 int
1500 rtx_to_tree_code (code)
1501 enum rtx_code code;
1502 {
1503 enum tree_code tcode;
1504
1505 switch (code)
1506 {
1507 case PLUS:
1508 tcode = PLUS_EXPR;
1509 break;
1510 case MINUS:
1511 tcode = MINUS_EXPR;
1512 break;
1513 case MULT:
1514 tcode = MULT_EXPR;
1515 break;
1516 case DIV:
1517 tcode = RDIV_EXPR;
1518 break;
1519 case SMIN:
1520 tcode = MIN_EXPR;
1521 break;
1522 case SMAX:
1523 tcode = MAX_EXPR;
1524 break;
1525 default:
1526 tcode = LAST_AND_UNUSED_TREE_CODE;
1527 break;
1528 }
1529 return ((int) tcode);
1530 }