s-carun8.adb, [...] (Compare_Array_?8): modify so that last full word is no longer...
[gcc.git] / gcc / explow.c
1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987, 1991, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
4 Free Software Foundation, Inc.
5
6 This file is part of GCC.
7
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 2, or (at your option) any later
11 version.
12
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to the Free
20 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
21 02110-1301, USA. */
22
23
24 #include "config.h"
25 #include "system.h"
26 #include "coretypes.h"
27 #include "tm.h"
28 #include "toplev.h"
29 #include "rtl.h"
30 #include "tree.h"
31 #include "tm_p.h"
32 #include "flags.h"
33 #include "function.h"
34 #include "expr.h"
35 #include "optabs.h"
36 #include "hard-reg-set.h"
37 #include "insn-config.h"
38 #include "ggc.h"
39 #include "recog.h"
40 #include "langhooks.h"
41 #include "target.h"
42 #include "output.h"
43
44 static rtx break_out_memory_refs (rtx);
45 static void emit_stack_probe (rtx);
46
47
48 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
49
50 HOST_WIDE_INT
51 trunc_int_for_mode (HOST_WIDE_INT c, enum machine_mode mode)
52 {
53 int width = GET_MODE_BITSIZE (mode);
54
55 /* You want to truncate to a _what_? */
56 gcc_assert (SCALAR_INT_MODE_P (mode));
57
58 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
59 if (mode == BImode)
60 return c & 1 ? STORE_FLAG_VALUE : 0;
61
62 /* Sign-extend for the requested mode. */
63
64 if (width < HOST_BITS_PER_WIDE_INT)
65 {
66 HOST_WIDE_INT sign = 1;
67 sign <<= width - 1;
68 c &= (sign << 1) - 1;
69 c ^= sign;
70 c -= sign;
71 }
72
73 return c;
74 }
75
76 /* Return an rtx for the sum of X and the integer C. */
77
78 rtx
79 plus_constant (rtx x, HOST_WIDE_INT c)
80 {
81 RTX_CODE code;
82 rtx y;
83 enum machine_mode mode;
84 rtx tem;
85 int all_constant = 0;
86
87 if (c == 0)
88 return x;
89
90 restart:
91
92 code = GET_CODE (x);
93 mode = GET_MODE (x);
94 y = x;
95
96 switch (code)
97 {
98 case CONST_INT:
99 return GEN_INT (INTVAL (x) + c);
100
101 case CONST_DOUBLE:
102 {
103 unsigned HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
104 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
105 unsigned HOST_WIDE_INT l2 = c;
106 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
107 unsigned HOST_WIDE_INT lv;
108 HOST_WIDE_INT hv;
109
110 add_double (l1, h1, l2, h2, &lv, &hv);
111
112 return immed_double_const (lv, hv, VOIDmode);
113 }
114
115 case MEM:
116 /* If this is a reference to the constant pool, try replacing it with
117 a reference to a new constant. If the resulting address isn't
118 valid, don't return it because we have no way to validize it. */
119 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
120 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
121 {
122 tem
123 = force_const_mem (GET_MODE (x),
124 plus_constant (get_pool_constant (XEXP (x, 0)),
125 c));
126 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
127 return tem;
128 }
129 break;
130
131 case CONST:
132 /* If adding to something entirely constant, set a flag
133 so that we can add a CONST around the result. */
134 x = XEXP (x, 0);
135 all_constant = 1;
136 goto restart;
137
138 case SYMBOL_REF:
139 case LABEL_REF:
140 all_constant = 1;
141 break;
142
143 case PLUS:
144 /* The interesting case is adding the integer to a sum.
145 Look for constant term in the sum and combine
146 with C. For an integer constant term, we make a combined
147 integer. For a constant term that is not an explicit integer,
148 we cannot really combine, but group them together anyway.
149
150 Restart or use a recursive call in case the remaining operand is
151 something that we handle specially, such as a SYMBOL_REF.
152
153 We may not immediately return from the recursive call here, lest
154 all_constant gets lost. */
155
156 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
157 {
158 c += INTVAL (XEXP (x, 1));
159
160 if (GET_MODE (x) != VOIDmode)
161 c = trunc_int_for_mode (c, GET_MODE (x));
162
163 x = XEXP (x, 0);
164 goto restart;
165 }
166 else if (CONSTANT_P (XEXP (x, 1)))
167 {
168 x = gen_rtx_PLUS (mode, XEXP (x, 0), plus_constant (XEXP (x, 1), c));
169 c = 0;
170 }
171 else if (find_constant_term_loc (&y))
172 {
173 /* We need to be careful since X may be shared and we can't
174 modify it in place. */
175 rtx copy = copy_rtx (x);
176 rtx *const_loc = find_constant_term_loc (&copy);
177
178 *const_loc = plus_constant (*const_loc, c);
179 x = copy;
180 c = 0;
181 }
182 break;
183
184 default:
185 break;
186 }
187
188 if (c != 0)
189 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
190
191 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
192 return x;
193 else if (all_constant)
194 return gen_rtx_CONST (mode, x);
195 else
196 return x;
197 }
198 \f
199 /* If X is a sum, return a new sum like X but lacking any constant terms.
200 Add all the removed constant terms into *CONSTPTR.
201 X itself is not altered. The result != X if and only if
202 it is not isomorphic to X. */
203
204 rtx
205 eliminate_constant_term (rtx x, rtx *constptr)
206 {
207 rtx x0, x1;
208 rtx tem;
209
210 if (GET_CODE (x) != PLUS)
211 return x;
212
213 /* First handle constants appearing at this level explicitly. */
214 if (GET_CODE (XEXP (x, 1)) == CONST_INT
215 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
216 XEXP (x, 1)))
217 && GET_CODE (tem) == CONST_INT)
218 {
219 *constptr = tem;
220 return eliminate_constant_term (XEXP (x, 0), constptr);
221 }
222
223 tem = const0_rtx;
224 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
225 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
226 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
227 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
228 *constptr, tem))
229 && GET_CODE (tem) == CONST_INT)
230 {
231 *constptr = tem;
232 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
233 }
234
235 return x;
236 }
237
238 /* Return an rtx for the size in bytes of the value of EXP. */
239
240 rtx
241 expr_size (tree exp)
242 {
243 tree size;
244
245 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
246 size = TREE_OPERAND (exp, 1);
247 else
248 {
249 size = lang_hooks.expr_size (exp);
250 gcc_assert (size);
251 size = SUBSTITUTE_PLACEHOLDER_IN_EXPR (size, exp);
252 }
253
254 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), 0);
255 }
256
257 /* Return a wide integer for the size in bytes of the value of EXP, or -1
258 if the size can vary or is larger than an integer. */
259
260 HOST_WIDE_INT
261 int_expr_size (tree exp)
262 {
263 tree size;
264
265 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
266 size = TREE_OPERAND (exp, 1);
267 else
268 {
269 size = lang_hooks.expr_size (exp);
270 gcc_assert (size);
271 }
272
273 if (size == 0 || !host_integerp (size, 0))
274 return -1;
275
276 return tree_low_cst (size, 0);
277 }
278 \f
279 /* Return a copy of X in which all memory references
280 and all constants that involve symbol refs
281 have been replaced with new temporary registers.
282 Also emit code to load the memory locations and constants
283 into those registers.
284
285 If X contains no such constants or memory references,
286 X itself (not a copy) is returned.
287
288 If a constant is found in the address that is not a legitimate constant
289 in an insn, it is left alone in the hope that it might be valid in the
290 address.
291
292 X may contain no arithmetic except addition, subtraction and multiplication.
293 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
294
295 static rtx
296 break_out_memory_refs (rtx x)
297 {
298 if (MEM_P (x)
299 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
300 && GET_MODE (x) != VOIDmode))
301 x = force_reg (GET_MODE (x), x);
302 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
303 || GET_CODE (x) == MULT)
304 {
305 rtx op0 = break_out_memory_refs (XEXP (x, 0));
306 rtx op1 = break_out_memory_refs (XEXP (x, 1));
307
308 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
309 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
310 }
311
312 return x;
313 }
314
315 /* Given X, a memory address in ptr_mode, convert it to an address
316 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
317 the fact that pointers are not allowed to overflow by commuting arithmetic
318 operations over conversions so that address arithmetic insns can be
319 used. */
320
321 rtx
322 convert_memory_address (enum machine_mode to_mode ATTRIBUTE_UNUSED,
323 rtx x)
324 {
325 #ifndef POINTERS_EXTEND_UNSIGNED
326 gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode);
327 return x;
328 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
329 enum machine_mode from_mode;
330 rtx temp;
331 enum rtx_code code;
332
333 /* If X already has the right mode, just return it. */
334 if (GET_MODE (x) == to_mode)
335 return x;
336
337 from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
338
339 /* Here we handle some special cases. If none of them apply, fall through
340 to the default case. */
341 switch (GET_CODE (x))
342 {
343 case CONST_INT:
344 case CONST_DOUBLE:
345 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
346 code = TRUNCATE;
347 else if (POINTERS_EXTEND_UNSIGNED < 0)
348 break;
349 else if (POINTERS_EXTEND_UNSIGNED > 0)
350 code = ZERO_EXTEND;
351 else
352 code = SIGN_EXTEND;
353 temp = simplify_unary_operation (code, to_mode, x, from_mode);
354 if (temp)
355 return temp;
356 break;
357
358 case SUBREG:
359 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
360 && GET_MODE (SUBREG_REG (x)) == to_mode)
361 return SUBREG_REG (x);
362 break;
363
364 case LABEL_REF:
365 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
366 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
367 return temp;
368 break;
369
370 case SYMBOL_REF:
371 temp = shallow_copy_rtx (x);
372 PUT_MODE (temp, to_mode);
373 return temp;
374 break;
375
376 case CONST:
377 return gen_rtx_CONST (to_mode,
378 convert_memory_address (to_mode, XEXP (x, 0)));
379 break;
380
381 case PLUS:
382 case MULT:
383 /* For addition we can safely permute the conversion and addition
384 operation if one operand is a constant and converting the constant
385 does not change it or if one operand is a constant and we are
386 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
387 We can always safely permute them if we are making the address
388 narrower. */
389 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
390 || (GET_CODE (x) == PLUS
391 && GET_CODE (XEXP (x, 1)) == CONST_INT
392 && (XEXP (x, 1) == convert_memory_address (to_mode, XEXP (x, 1))
393 || POINTERS_EXTEND_UNSIGNED < 0)))
394 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
395 convert_memory_address (to_mode, XEXP (x, 0)),
396 XEXP (x, 1));
397 break;
398
399 default:
400 break;
401 }
402
403 return convert_modes (to_mode, from_mode,
404 x, POINTERS_EXTEND_UNSIGNED);
405 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
406 }
407 \f
408 /* Return something equivalent to X but valid as a memory address
409 for something of mode MODE. When X is not itself valid, this
410 works by copying X or subexpressions of it into registers. */
411
412 rtx
413 memory_address (enum machine_mode mode, rtx x)
414 {
415 rtx oldx = x;
416
417 x = convert_memory_address (Pmode, x);
418
419 /* By passing constant addresses through registers
420 we get a chance to cse them. */
421 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
422 x = force_reg (Pmode, x);
423
424 /* We get better cse by rejecting indirect addressing at this stage.
425 Let the combiner create indirect addresses where appropriate.
426 For now, generate the code so that the subexpressions useful to share
427 are visible. But not if cse won't be done! */
428 else
429 {
430 if (! cse_not_expected && !REG_P (x))
431 x = break_out_memory_refs (x);
432
433 /* At this point, any valid address is accepted. */
434 if (memory_address_p (mode, x))
435 goto win;
436
437 /* If it was valid before but breaking out memory refs invalidated it,
438 use it the old way. */
439 if (memory_address_p (mode, oldx))
440 goto win2;
441
442 /* Perform machine-dependent transformations on X
443 in certain cases. This is not necessary since the code
444 below can handle all possible cases, but machine-dependent
445 transformations can make better code. */
446 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
447
448 /* PLUS and MULT can appear in special ways
449 as the result of attempts to make an address usable for indexing.
450 Usually they are dealt with by calling force_operand, below.
451 But a sum containing constant terms is special
452 if removing them makes the sum a valid address:
453 then we generate that address in a register
454 and index off of it. We do this because it often makes
455 shorter code, and because the addresses thus generated
456 in registers often become common subexpressions. */
457 if (GET_CODE (x) == PLUS)
458 {
459 rtx constant_term = const0_rtx;
460 rtx y = eliminate_constant_term (x, &constant_term);
461 if (constant_term == const0_rtx
462 || ! memory_address_p (mode, y))
463 x = force_operand (x, NULL_RTX);
464 else
465 {
466 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
467 if (! memory_address_p (mode, y))
468 x = force_operand (x, NULL_RTX);
469 else
470 x = y;
471 }
472 }
473
474 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
475 x = force_operand (x, NULL_RTX);
476
477 /* If we have a register that's an invalid address,
478 it must be a hard reg of the wrong class. Copy it to a pseudo. */
479 else if (REG_P (x))
480 x = copy_to_reg (x);
481
482 /* Last resort: copy the value to a register, since
483 the register is a valid address. */
484 else
485 x = force_reg (Pmode, x);
486
487 goto done;
488
489 win2:
490 x = oldx;
491 win:
492 if (flag_force_addr && ! cse_not_expected && !REG_P (x))
493 {
494 x = force_operand (x, NULL_RTX);
495 x = force_reg (Pmode, x);
496 }
497 }
498
499 done:
500
501 /* If we didn't change the address, we are done. Otherwise, mark
502 a reg as a pointer if we have REG or REG + CONST_INT. */
503 if (oldx == x)
504 return x;
505 else if (REG_P (x))
506 mark_reg_pointer (x, BITS_PER_UNIT);
507 else if (GET_CODE (x) == PLUS
508 && REG_P (XEXP (x, 0))
509 && GET_CODE (XEXP (x, 1)) == CONST_INT)
510 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
511
512 /* OLDX may have been the address on a temporary. Update the address
513 to indicate that X is now used. */
514 update_temp_slot_address (oldx, x);
515
516 return x;
517 }
518
519 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
520
521 rtx
522 memory_address_noforce (enum machine_mode mode, rtx x)
523 {
524 int ambient_force_addr = flag_force_addr;
525 rtx val;
526
527 flag_force_addr = 0;
528 val = memory_address (mode, x);
529 flag_force_addr = ambient_force_addr;
530 return val;
531 }
532
533 /* Convert a mem ref into one with a valid memory address.
534 Pass through anything else unchanged. */
535
536 rtx
537 validize_mem (rtx ref)
538 {
539 if (!MEM_P (ref))
540 return ref;
541 ref = use_anchored_address (ref);
542 if (! (flag_force_addr && CONSTANT_ADDRESS_P (XEXP (ref, 0)))
543 && memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
544 return ref;
545
546 /* Don't alter REF itself, since that is probably a stack slot. */
547 return replace_equiv_address (ref, XEXP (ref, 0));
548 }
549
550 /* If X is a memory reference to a member of an object block, try rewriting
551 it to use an anchor instead. Return the new memory reference on success
552 and the old one on failure. */
553
554 rtx
555 use_anchored_address (rtx x)
556 {
557 rtx base;
558 HOST_WIDE_INT offset;
559
560 if (!flag_section_anchors)
561 return x;
562
563 if (!MEM_P (x))
564 return x;
565
566 /* Split the address into a base and offset. */
567 base = XEXP (x, 0);
568 offset = 0;
569 if (GET_CODE (base) == CONST
570 && GET_CODE (XEXP (base, 0)) == PLUS
571 && GET_CODE (XEXP (XEXP (base, 0), 1)) == CONST_INT)
572 {
573 offset += INTVAL (XEXP (XEXP (base, 0), 1));
574 base = XEXP (XEXP (base, 0), 0);
575 }
576
577 /* Check whether BASE is suitable for anchors. */
578 if (GET_CODE (base) != SYMBOL_REF
579 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base)
580 || SYMBOL_REF_ANCHOR_P (base)
581 || SYMBOL_REF_BLOCK (base) == NULL
582 || !targetm.use_anchors_for_symbol_p (base))
583 return x;
584
585 /* Decide where BASE is going to be. */
586 place_block_symbol (base);
587
588 /* Get the anchor we need to use. */
589 offset += SYMBOL_REF_BLOCK_OFFSET (base);
590 base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset,
591 SYMBOL_REF_TLS_MODEL (base));
592
593 /* Work out the offset from the anchor. */
594 offset -= SYMBOL_REF_BLOCK_OFFSET (base);
595
596 /* If we're going to run a CSE pass, force the anchor into a register.
597 We will then be able to reuse registers for several accesses, if the
598 target costs say that that's worthwhile. */
599 if (!cse_not_expected)
600 base = force_reg (GET_MODE (base), base);
601
602 return replace_equiv_address (x, plus_constant (base, offset));
603 }
604 \f
605 /* Copy the value or contents of X to a new temp reg and return that reg. */
606
607 rtx
608 copy_to_reg (rtx x)
609 {
610 rtx temp = gen_reg_rtx (GET_MODE (x));
611
612 /* If not an operand, must be an address with PLUS and MULT so
613 do the computation. */
614 if (! general_operand (x, VOIDmode))
615 x = force_operand (x, temp);
616
617 if (x != temp)
618 emit_move_insn (temp, x);
619
620 return temp;
621 }
622
623 /* Like copy_to_reg but always give the new register mode Pmode
624 in case X is a constant. */
625
626 rtx
627 copy_addr_to_reg (rtx x)
628 {
629 return copy_to_mode_reg (Pmode, x);
630 }
631
632 /* Like copy_to_reg but always give the new register mode MODE
633 in case X is a constant. */
634
635 rtx
636 copy_to_mode_reg (enum machine_mode mode, rtx x)
637 {
638 rtx temp = gen_reg_rtx (mode);
639
640 /* If not an operand, must be an address with PLUS and MULT so
641 do the computation. */
642 if (! general_operand (x, VOIDmode))
643 x = force_operand (x, temp);
644
645 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode);
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 (enum machine_mode mode, rtx x)
661 {
662 rtx temp, insn, set;
663
664 if (REG_P (x))
665 return x;
666
667 if (general_operand (x, mode))
668 {
669 temp = gen_reg_rtx (mode);
670 insn = emit_move_insn (temp, x);
671 }
672 else
673 {
674 temp = force_operand (x, NULL_RTX);
675 if (REG_P (temp))
676 insn = get_last_insn ();
677 else
678 {
679 rtx temp2 = gen_reg_rtx (mode);
680 insn = emit_move_insn (temp2, temp);
681 temp = temp2;
682 }
683 }
684
685 /* Let optimizers know that TEMP's value never changes
686 and that X can be substituted for it. Don't get confused
687 if INSN set something else (such as a SUBREG of TEMP). */
688 if (CONSTANT_P (x)
689 && (set = single_set (insn)) != 0
690 && SET_DEST (set) == temp
691 && ! rtx_equal_p (x, SET_SRC (set)))
692 set_unique_reg_note (insn, REG_EQUAL, x);
693
694 /* Let optimizers know that TEMP is a pointer, and if so, the
695 known alignment of that pointer. */
696 {
697 unsigned align = 0;
698 if (GET_CODE (x) == SYMBOL_REF)
699 {
700 align = BITS_PER_UNIT;
701 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
702 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
703 }
704 else if (GET_CODE (x) == LABEL_REF)
705 align = BITS_PER_UNIT;
706 else if (GET_CODE (x) == CONST
707 && GET_CODE (XEXP (x, 0)) == PLUS
708 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
709 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT)
710 {
711 rtx s = XEXP (XEXP (x, 0), 0);
712 rtx c = XEXP (XEXP (x, 0), 1);
713 unsigned sa, ca;
714
715 sa = BITS_PER_UNIT;
716 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
717 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
718
719 ca = exact_log2 (INTVAL (c) & -INTVAL (c)) * BITS_PER_UNIT;
720
721 align = MIN (sa, ca);
722 }
723 else if (MEM_P (x) && MEM_POINTER (x))
724 align = MEM_ALIGN (x);
725
726 if (align)
727 mark_reg_pointer (temp, align);
728 }
729
730 return temp;
731 }
732
733 /* If X is a memory ref, copy its contents to a new temp reg and return
734 that reg. Otherwise, return X. */
735
736 rtx
737 force_not_mem (rtx x)
738 {
739 rtx temp;
740
741 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
742 return x;
743
744 temp = gen_reg_rtx (GET_MODE (x));
745
746 if (MEM_POINTER (x))
747 REG_POINTER (temp) = 1;
748
749 emit_move_insn (temp, x);
750 return temp;
751 }
752
753 /* Copy X to TARGET (if it's nonzero and a reg)
754 or to a new temp reg and return that reg.
755 MODE is the mode to use for X in case it is a constant. */
756
757 rtx
758 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode)
759 {
760 rtx temp;
761
762 if (target && REG_P (target))
763 temp = target;
764 else
765 temp = gen_reg_rtx (mode);
766
767 emit_move_insn (temp, x);
768 return temp;
769 }
770 \f
771 /* Return the mode to use to store a scalar of TYPE and MODE.
772 PUNSIGNEDP points to the signedness of the type and may be adjusted
773 to show what signedness to use on extension operations.
774
775 FOR_CALL is nonzero if this call is promoting args for a call. */
776
777 #if defined(PROMOTE_MODE) && !defined(PROMOTE_FUNCTION_MODE)
778 #define PROMOTE_FUNCTION_MODE PROMOTE_MODE
779 #endif
780
781 enum machine_mode
782 promote_mode (tree type, enum machine_mode mode, int *punsignedp,
783 int for_call ATTRIBUTE_UNUSED)
784 {
785 enum tree_code code = TREE_CODE (type);
786 int unsignedp = *punsignedp;
787
788 #ifndef PROMOTE_MODE
789 if (! for_call)
790 return mode;
791 #endif
792
793 switch (code)
794 {
795 #ifdef PROMOTE_FUNCTION_MODE
796 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
797 case REAL_TYPE: case OFFSET_TYPE:
798 #ifdef PROMOTE_MODE
799 if (for_call)
800 {
801 #endif
802 PROMOTE_FUNCTION_MODE (mode, unsignedp, type);
803 #ifdef PROMOTE_MODE
804 }
805 else
806 {
807 PROMOTE_MODE (mode, unsignedp, type);
808 }
809 #endif
810 break;
811 #endif
812
813 #ifdef POINTERS_EXTEND_UNSIGNED
814 case REFERENCE_TYPE:
815 case POINTER_TYPE:
816 mode = Pmode;
817 unsignedp = POINTERS_EXTEND_UNSIGNED;
818 break;
819 #endif
820
821 default:
822 break;
823 }
824
825 *punsignedp = unsignedp;
826 return mode;
827 }
828 \f
829 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
830 This pops when ADJUST is positive. ADJUST need not be constant. */
831
832 void
833 adjust_stack (rtx adjust)
834 {
835 rtx temp;
836
837 if (adjust == const0_rtx)
838 return;
839
840 /* We expect all variable sized adjustments to be multiple of
841 PREFERRED_STACK_BOUNDARY. */
842 if (GET_CODE (adjust) == CONST_INT)
843 stack_pointer_delta -= INTVAL (adjust);
844
845 temp = expand_binop (Pmode,
846 #ifdef STACK_GROWS_DOWNWARD
847 add_optab,
848 #else
849 sub_optab,
850 #endif
851 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
852 OPTAB_LIB_WIDEN);
853
854 if (temp != stack_pointer_rtx)
855 emit_move_insn (stack_pointer_rtx, temp);
856 }
857
858 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
859 This pushes when ADJUST is positive. ADJUST need not be constant. */
860
861 void
862 anti_adjust_stack (rtx adjust)
863 {
864 rtx temp;
865
866 if (adjust == const0_rtx)
867 return;
868
869 /* We expect all variable sized adjustments to be multiple of
870 PREFERRED_STACK_BOUNDARY. */
871 if (GET_CODE (adjust) == CONST_INT)
872 stack_pointer_delta += INTVAL (adjust);
873
874 temp = expand_binop (Pmode,
875 #ifdef STACK_GROWS_DOWNWARD
876 sub_optab,
877 #else
878 add_optab,
879 #endif
880 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
881 OPTAB_LIB_WIDEN);
882
883 if (temp != stack_pointer_rtx)
884 emit_move_insn (stack_pointer_rtx, temp);
885 }
886
887 /* Round the size of a block to be pushed up to the boundary required
888 by this machine. SIZE is the desired size, which need not be constant. */
889
890 static rtx
891 round_push (rtx size)
892 {
893 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
894
895 if (align == 1)
896 return size;
897
898 if (GET_CODE (size) == CONST_INT)
899 {
900 HOST_WIDE_INT new = (INTVAL (size) + align - 1) / align * align;
901
902 if (INTVAL (size) != new)
903 size = GEN_INT (new);
904 }
905 else
906 {
907 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
908 but we know it can't. So add ourselves and then do
909 TRUNC_DIV_EXPR. */
910 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
911 NULL_RTX, 1, OPTAB_LIB_WIDEN);
912 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
913 NULL_RTX, 1);
914 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
915 }
916
917 return size;
918 }
919 \f
920 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
921 to a previously-created save area. If no save area has been allocated,
922 this function will allocate one. If a save area is specified, it
923 must be of the proper mode.
924
925 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
926 are emitted at the current position. */
927
928 void
929 emit_stack_save (enum save_level save_level, rtx *psave, rtx after)
930 {
931 rtx sa = *psave;
932 /* The default is that we use a move insn and save in a Pmode object. */
933 rtx (*fcn) (rtx, rtx) = gen_move_insn;
934 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
935
936 /* See if this machine has anything special to do for this kind of save. */
937 switch (save_level)
938 {
939 #ifdef HAVE_save_stack_block
940 case SAVE_BLOCK:
941 if (HAVE_save_stack_block)
942 fcn = gen_save_stack_block;
943 break;
944 #endif
945 #ifdef HAVE_save_stack_function
946 case SAVE_FUNCTION:
947 if (HAVE_save_stack_function)
948 fcn = gen_save_stack_function;
949 break;
950 #endif
951 #ifdef HAVE_save_stack_nonlocal
952 case SAVE_NONLOCAL:
953 if (HAVE_save_stack_nonlocal)
954 fcn = gen_save_stack_nonlocal;
955 break;
956 #endif
957 default:
958 break;
959 }
960
961 /* If there is no save area and we have to allocate one, do so. Otherwise
962 verify the save area is the proper mode. */
963
964 if (sa == 0)
965 {
966 if (mode != VOIDmode)
967 {
968 if (save_level == SAVE_NONLOCAL)
969 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
970 else
971 *psave = sa = gen_reg_rtx (mode);
972 }
973 }
974
975 if (after)
976 {
977 rtx seq;
978
979 start_sequence ();
980 do_pending_stack_adjust ();
981 /* We must validize inside the sequence, to ensure that any instructions
982 created by the validize call also get moved to the right place. */
983 if (sa != 0)
984 sa = validize_mem (sa);
985 emit_insn (fcn (sa, stack_pointer_rtx));
986 seq = get_insns ();
987 end_sequence ();
988 emit_insn_after (seq, after);
989 }
990 else
991 {
992 do_pending_stack_adjust ();
993 if (sa != 0)
994 sa = validize_mem (sa);
995 emit_insn (fcn (sa, stack_pointer_rtx));
996 }
997 }
998
999 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1000 area made by emit_stack_save. If it is zero, we have nothing to do.
1001
1002 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1003 current position. */
1004
1005 void
1006 emit_stack_restore (enum save_level save_level, rtx sa, rtx after)
1007 {
1008 /* The default is that we use a move insn. */
1009 rtx (*fcn) (rtx, rtx) = gen_move_insn;
1010
1011 /* See if this machine has anything special to do for this kind of save. */
1012 switch (save_level)
1013 {
1014 #ifdef HAVE_restore_stack_block
1015 case SAVE_BLOCK:
1016 if (HAVE_restore_stack_block)
1017 fcn = gen_restore_stack_block;
1018 break;
1019 #endif
1020 #ifdef HAVE_restore_stack_function
1021 case SAVE_FUNCTION:
1022 if (HAVE_restore_stack_function)
1023 fcn = gen_restore_stack_function;
1024 break;
1025 #endif
1026 #ifdef HAVE_restore_stack_nonlocal
1027 case SAVE_NONLOCAL:
1028 if (HAVE_restore_stack_nonlocal)
1029 fcn = gen_restore_stack_nonlocal;
1030 break;
1031 #endif
1032 default:
1033 break;
1034 }
1035
1036 if (sa != 0)
1037 {
1038 sa = validize_mem (sa);
1039 /* These clobbers prevent the scheduler from moving
1040 references to variable arrays below the code
1041 that deletes (pops) the arrays. */
1042 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1043 gen_rtx_MEM (BLKmode,
1044 gen_rtx_SCRATCH (VOIDmode))));
1045 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1046 gen_rtx_MEM (BLKmode, stack_pointer_rtx)));
1047 }
1048
1049 discard_pending_stack_adjust ();
1050
1051 if (after)
1052 {
1053 rtx seq;
1054
1055 start_sequence ();
1056 emit_insn (fcn (stack_pointer_rtx, sa));
1057 seq = get_insns ();
1058 end_sequence ();
1059 emit_insn_after (seq, after);
1060 }
1061 else
1062 emit_insn (fcn (stack_pointer_rtx, sa));
1063 }
1064
1065 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1066 function. This function should be called whenever we allocate or
1067 deallocate dynamic stack space. */
1068
1069 void
1070 update_nonlocal_goto_save_area (void)
1071 {
1072 tree t_save;
1073 rtx r_save;
1074
1075 /* The nonlocal_goto_save_area object is an array of N pointers. The
1076 first one is used for the frame pointer save; the rest are sized by
1077 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1078 of the stack save area slots. */
1079 t_save = build4 (ARRAY_REF, ptr_type_node, cfun->nonlocal_goto_save_area,
1080 integer_one_node, NULL_TREE, NULL_TREE);
1081 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1082
1083 emit_stack_save (SAVE_NONLOCAL, &r_save, NULL_RTX);
1084 }
1085 \f
1086 /* Return an rtx representing the address of an area of memory dynamically
1087 pushed on the stack. This region of memory is always aligned to
1088 a multiple of BIGGEST_ALIGNMENT.
1089
1090 Any required stack pointer alignment is preserved.
1091
1092 SIZE is an rtx representing the size of the area.
1093 TARGET is a place in which the address can be placed.
1094
1095 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1096
1097 rtx
1098 allocate_dynamic_stack_space (rtx size, rtx target, int known_align)
1099 {
1100 /* If we're asking for zero bytes, it doesn't matter what we point
1101 to since we can't dereference it. But return a reasonable
1102 address anyway. */
1103 if (size == const0_rtx)
1104 return virtual_stack_dynamic_rtx;
1105
1106 /* Otherwise, show we're calling alloca or equivalent. */
1107 current_function_calls_alloca = 1;
1108
1109 /* Ensure the size is in the proper mode. */
1110 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1111 size = convert_to_mode (Pmode, size, 1);
1112
1113 /* We can't attempt to minimize alignment necessary, because we don't
1114 know the final value of preferred_stack_boundary yet while executing
1115 this code. */
1116 cfun->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1117
1118 /* We will need to ensure that the address we return is aligned to
1119 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1120 always know its final value at this point in the compilation (it
1121 might depend on the size of the outgoing parameter lists, for
1122 example), so we must align the value to be returned in that case.
1123 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1124 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1125 We must also do an alignment operation on the returned value if
1126 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1127
1128 If we have to align, we must leave space in SIZE for the hole
1129 that might result from the alignment operation. */
1130
1131 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1132 #define MUST_ALIGN 1
1133 #else
1134 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1135 #endif
1136
1137 if (MUST_ALIGN)
1138 size
1139 = force_operand (plus_constant (size,
1140 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1141 NULL_RTX);
1142
1143 #ifdef SETJMP_VIA_SAVE_AREA
1144 /* If setjmp restores regs from a save area in the stack frame,
1145 avoid clobbering the reg save area. Note that the offset of
1146 virtual_incoming_args_rtx includes the preallocated stack args space.
1147 It would be no problem to clobber that, but it's on the wrong side
1148 of the old save area.
1149
1150 What used to happen is that, since we did not know for sure
1151 whether setjmp() was invoked until after RTL generation, we
1152 would use reg notes to store the "optimized" size and fix things
1153 up later. These days we know this information before we ever
1154 start building RTL so the reg notes are unnecessary. */
1155 if (!current_function_calls_setjmp)
1156 {
1157 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1158
1159 /* ??? Code below assumes that the save area needs maximal
1160 alignment. This constraint may be too strong. */
1161 gcc_assert (PREFERRED_STACK_BOUNDARY == BIGGEST_ALIGNMENT);
1162
1163 if (GET_CODE (size) == CONST_INT)
1164 {
1165 HOST_WIDE_INT new = INTVAL (size) / align * align;
1166
1167 if (INTVAL (size) != new)
1168 size = GEN_INT (new);
1169 }
1170 else
1171 {
1172 /* Since we know overflow is not possible, we avoid using
1173 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1174 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1175 GEN_INT (align), NULL_RTX, 1);
1176 size = expand_mult (Pmode, size,
1177 GEN_INT (align), NULL_RTX, 1);
1178 }
1179 }
1180 else
1181 {
1182 rtx dynamic_offset
1183 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1184 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1185
1186 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1187 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1188 }
1189 #endif /* SETJMP_VIA_SAVE_AREA */
1190
1191 /* Round the size to a multiple of the required stack alignment.
1192 Since the stack if presumed to be rounded before this allocation,
1193 this will maintain the required alignment.
1194
1195 If the stack grows downward, we could save an insn by subtracting
1196 SIZE from the stack pointer and then aligning the stack pointer.
1197 The problem with this is that the stack pointer may be unaligned
1198 between the execution of the subtraction and alignment insns and
1199 some machines do not allow this. Even on those that do, some
1200 signal handlers malfunction if a signal should occur between those
1201 insns. Since this is an extremely rare event, we have no reliable
1202 way of knowing which systems have this problem. So we avoid even
1203 momentarily mis-aligning the stack. */
1204
1205 /* If we added a variable amount to SIZE,
1206 we can no longer assume it is aligned. */
1207 #if !defined (SETJMP_VIA_SAVE_AREA)
1208 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1209 #endif
1210 size = round_push (size);
1211
1212 do_pending_stack_adjust ();
1213
1214 /* We ought to be called always on the toplevel and stack ought to be aligned
1215 properly. */
1216 gcc_assert (!(stack_pointer_delta
1217 % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)));
1218
1219 /* If needed, check that we have the required amount of stack. Take into
1220 account what has already been checked. */
1221 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1222 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1223
1224 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1225 if (target == 0 || !REG_P (target)
1226 || REGNO (target) < FIRST_PSEUDO_REGISTER
1227 || GET_MODE (target) != Pmode)
1228 target = gen_reg_rtx (Pmode);
1229
1230 mark_reg_pointer (target, known_align);
1231
1232 /* Perform the required allocation from the stack. Some systems do
1233 this differently than simply incrementing/decrementing from the
1234 stack pointer, such as acquiring the space by calling malloc(). */
1235 #ifdef HAVE_allocate_stack
1236 if (HAVE_allocate_stack)
1237 {
1238 enum machine_mode mode = STACK_SIZE_MODE;
1239 insn_operand_predicate_fn pred;
1240
1241 /* We don't have to check against the predicate for operand 0 since
1242 TARGET is known to be a pseudo of the proper mode, which must
1243 be valid for the operand. For operand 1, convert to the
1244 proper mode and validate. */
1245 if (mode == VOIDmode)
1246 mode = insn_data[(int) CODE_FOR_allocate_stack].operand[1].mode;
1247
1248 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1249 if (pred && ! ((*pred) (size, mode)))
1250 size = copy_to_mode_reg (mode, convert_to_mode (mode, size, 1));
1251
1252 emit_insn (gen_allocate_stack (target, size));
1253 }
1254 else
1255 #endif
1256 {
1257 #ifndef STACK_GROWS_DOWNWARD
1258 emit_move_insn (target, virtual_stack_dynamic_rtx);
1259 #endif
1260
1261 /* Check stack bounds if necessary. */
1262 if (current_function_limit_stack)
1263 {
1264 rtx available;
1265 rtx space_available = gen_label_rtx ();
1266 #ifdef STACK_GROWS_DOWNWARD
1267 available = expand_binop (Pmode, sub_optab,
1268 stack_pointer_rtx, stack_limit_rtx,
1269 NULL_RTX, 1, OPTAB_WIDEN);
1270 #else
1271 available = expand_binop (Pmode, sub_optab,
1272 stack_limit_rtx, stack_pointer_rtx,
1273 NULL_RTX, 1, OPTAB_WIDEN);
1274 #endif
1275 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1276 space_available);
1277 #ifdef HAVE_trap
1278 if (HAVE_trap)
1279 emit_insn (gen_trap ());
1280 else
1281 #endif
1282 error ("stack limits not supported on this target");
1283 emit_barrier ();
1284 emit_label (space_available);
1285 }
1286
1287 anti_adjust_stack (size);
1288
1289 #ifdef STACK_GROWS_DOWNWARD
1290 emit_move_insn (target, virtual_stack_dynamic_rtx);
1291 #endif
1292 }
1293
1294 if (MUST_ALIGN)
1295 {
1296 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1297 but we know it can't. So add ourselves and then do
1298 TRUNC_DIV_EXPR. */
1299 target = expand_binop (Pmode, add_optab, target,
1300 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1301 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1302 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1303 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1304 NULL_RTX, 1);
1305 target = expand_mult (Pmode, target,
1306 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1307 NULL_RTX, 1);
1308 }
1309
1310 /* Record the new stack level for nonlocal gotos. */
1311 if (cfun->nonlocal_goto_save_area != 0)
1312 update_nonlocal_goto_save_area ();
1313
1314 return target;
1315 }
1316 \f
1317 /* A front end may want to override GCC's stack checking by providing a
1318 run-time routine to call to check the stack, so provide a mechanism for
1319 calling that routine. */
1320
1321 static GTY(()) rtx stack_check_libfunc;
1322
1323 void
1324 set_stack_check_libfunc (rtx libfunc)
1325 {
1326 stack_check_libfunc = libfunc;
1327 }
1328 \f
1329 /* Emit one stack probe at ADDRESS, an address within the stack. */
1330
1331 static void
1332 emit_stack_probe (rtx address)
1333 {
1334 rtx memref = gen_rtx_MEM (word_mode, address);
1335
1336 MEM_VOLATILE_P (memref) = 1;
1337
1338 if (STACK_CHECK_PROBE_LOAD)
1339 emit_move_insn (gen_reg_rtx (word_mode), memref);
1340 else
1341 emit_move_insn (memref, const0_rtx);
1342 }
1343
1344 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1345 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1346 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1347 subtract from the stack. If SIZE is constant, this is done
1348 with a fixed number of probes. Otherwise, we must make a loop. */
1349
1350 #ifdef STACK_GROWS_DOWNWARD
1351 #define STACK_GROW_OP MINUS
1352 #else
1353 #define STACK_GROW_OP PLUS
1354 #endif
1355
1356 void
1357 probe_stack_range (HOST_WIDE_INT first, rtx size)
1358 {
1359 /* First ensure SIZE is Pmode. */
1360 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1361 size = convert_to_mode (Pmode, size, 1);
1362
1363 /* Next see if the front end has set up a function for us to call to
1364 check the stack. */
1365 if (stack_check_libfunc != 0)
1366 {
1367 rtx addr = memory_address (QImode,
1368 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1369 stack_pointer_rtx,
1370 plus_constant (size, first)));
1371
1372 addr = convert_memory_address (ptr_mode, addr);
1373 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1374 ptr_mode);
1375 }
1376
1377 /* Next see if we have an insn to check the stack. Use it if so. */
1378 #ifdef HAVE_check_stack
1379 else if (HAVE_check_stack)
1380 {
1381 insn_operand_predicate_fn pred;
1382 rtx last_addr
1383 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1384 stack_pointer_rtx,
1385 plus_constant (size, first)),
1386 NULL_RTX);
1387
1388 pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1389 if (pred && ! ((*pred) (last_addr, Pmode)))
1390 last_addr = copy_to_mode_reg (Pmode, last_addr);
1391
1392 emit_insn (gen_check_stack (last_addr));
1393 }
1394 #endif
1395
1396 /* If we have to generate explicit probes, see if we have a constant
1397 small number of them to generate. If so, that's the easy case. */
1398 else if (GET_CODE (size) == CONST_INT
1399 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1400 {
1401 HOST_WIDE_INT offset;
1402
1403 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1404 for values of N from 1 until it exceeds LAST. If only one
1405 probe is needed, this will not generate any code. Then probe
1406 at LAST. */
1407 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1408 offset < INTVAL (size);
1409 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1410 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1411 stack_pointer_rtx,
1412 GEN_INT (offset)));
1413
1414 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1415 stack_pointer_rtx,
1416 plus_constant (size, first)));
1417 }
1418
1419 /* In the variable case, do the same as above, but in a loop. We emit loop
1420 notes so that loop optimization can be done. */
1421 else
1422 {
1423 rtx test_addr
1424 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1425 stack_pointer_rtx,
1426 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1427 NULL_RTX);
1428 rtx last_addr
1429 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1430 stack_pointer_rtx,
1431 plus_constant (size, first)),
1432 NULL_RTX);
1433 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1434 rtx loop_lab = gen_label_rtx ();
1435 rtx test_lab = gen_label_rtx ();
1436 rtx end_lab = gen_label_rtx ();
1437 rtx temp;
1438
1439 if (!REG_P (test_addr)
1440 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1441 test_addr = force_reg (Pmode, test_addr);
1442
1443 emit_jump (test_lab);
1444
1445 emit_label (loop_lab);
1446 emit_stack_probe (test_addr);
1447
1448 #ifdef STACK_GROWS_DOWNWARD
1449 #define CMP_OPCODE GTU
1450 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1451 1, OPTAB_WIDEN);
1452 #else
1453 #define CMP_OPCODE LTU
1454 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1455 1, OPTAB_WIDEN);
1456 #endif
1457
1458 gcc_assert (temp == test_addr);
1459
1460 emit_label (test_lab);
1461 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1462 NULL_RTX, Pmode, 1, loop_lab);
1463 emit_jump (end_lab);
1464 emit_label (end_lab);
1465
1466 emit_stack_probe (last_addr);
1467 }
1468 }
1469 \f
1470 /* Return an rtx representing the register or memory location
1471 in which a scalar value of data type VALTYPE
1472 was returned by a function call to function FUNC.
1473 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1474 function is known, otherwise 0.
1475 OUTGOING is 1 if on a machine with register windows this function
1476 should return the register in which the function will put its result
1477 and 0 otherwise. */
1478
1479 rtx
1480 hard_function_value (tree valtype, tree func, tree fntype,
1481 int outgoing ATTRIBUTE_UNUSED)
1482 {
1483 rtx val;
1484
1485 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing);
1486
1487 if (REG_P (val)
1488 && GET_MODE (val) == BLKmode)
1489 {
1490 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1491 enum machine_mode tmpmode;
1492
1493 /* int_size_in_bytes can return -1. We don't need a check here
1494 since the value of bytes will then be large enough that no
1495 mode will match anyway. */
1496
1497 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1498 tmpmode != VOIDmode;
1499 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1500 {
1501 /* Have we found a large enough mode? */
1502 if (GET_MODE_SIZE (tmpmode) >= bytes)
1503 break;
1504 }
1505
1506 /* No suitable mode found. */
1507 gcc_assert (tmpmode != VOIDmode);
1508
1509 PUT_MODE (val, tmpmode);
1510 }
1511 return val;
1512 }
1513
1514 /* Return an rtx representing the register or memory location
1515 in which a scalar value of mode MODE was returned by a library call. */
1516
1517 rtx
1518 hard_libcall_value (enum machine_mode mode)
1519 {
1520 return LIBCALL_VALUE (mode);
1521 }
1522
1523 /* Look up the tree code for a given rtx code
1524 to provide the arithmetic operation for REAL_ARITHMETIC.
1525 The function returns an int because the caller may not know
1526 what `enum tree_code' means. */
1527
1528 int
1529 rtx_to_tree_code (enum rtx_code code)
1530 {
1531 enum tree_code tcode;
1532
1533 switch (code)
1534 {
1535 case PLUS:
1536 tcode = PLUS_EXPR;
1537 break;
1538 case MINUS:
1539 tcode = MINUS_EXPR;
1540 break;
1541 case MULT:
1542 tcode = MULT_EXPR;
1543 break;
1544 case DIV:
1545 tcode = RDIV_EXPR;
1546 break;
1547 case SMIN:
1548 tcode = MIN_EXPR;
1549 break;
1550 case SMAX:
1551 tcode = MAX_EXPR;
1552 break;
1553 default:
1554 tcode = LAST_AND_UNUSED_TREE_CODE;
1555 break;
1556 }
1557 return ((int) tcode);
1558 }
1559
1560 #include "gt-explow.h"