cp-objcp-common.c (cp_expr_size): Return NULL in the case size is undefined.
[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. We can always safely permute them if we are
386 making the address narrower. */
387 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
388 || (GET_CODE (x) == PLUS
389 && GET_CODE (XEXP (x, 1)) == CONST_INT
390 && XEXP (x, 1) == convert_memory_address (to_mode, XEXP (x, 1))))
391 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
392 convert_memory_address (to_mode, XEXP (x, 0)),
393 XEXP (x, 1));
394 break;
395
396 default:
397 break;
398 }
399
400 return convert_modes (to_mode, from_mode,
401 x, POINTERS_EXTEND_UNSIGNED);
402 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
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 (enum machine_mode mode, rtx x)
411 {
412 rtx oldx = x;
413
414 x = convert_memory_address (Pmode, x);
415
416 /* By passing constant addresses through registers
417 we get a chance to cse them. */
418 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
419 x = force_reg (Pmode, x);
420
421 /* We get better cse by rejecting indirect addressing at this stage.
422 Let the combiner create indirect addresses where appropriate.
423 For now, generate the code so that the subexpressions useful to share
424 are visible. But not if cse won't be done! */
425 else
426 {
427 if (! cse_not_expected && !REG_P (x))
428 x = break_out_memory_refs (x);
429
430 /* At this point, any valid address is accepted. */
431 if (memory_address_p (mode, x))
432 goto win;
433
434 /* If it was valid before but breaking out memory refs invalidated it,
435 use it the old way. */
436 if (memory_address_p (mode, oldx))
437 goto win2;
438
439 /* Perform machine-dependent transformations on X
440 in certain cases. This is not necessary since the code
441 below can handle all possible cases, but machine-dependent
442 transformations can make better code. */
443 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
444
445 /* PLUS and MULT can appear in special ways
446 as the result of attempts to make an address usable for indexing.
447 Usually they are dealt with by calling force_operand, below.
448 But a sum containing constant terms is special
449 if removing them makes the sum a valid address:
450 then we generate that address in a register
451 and index off of it. We do this because it often makes
452 shorter code, and because the addresses thus generated
453 in registers often become common subexpressions. */
454 if (GET_CODE (x) == PLUS)
455 {
456 rtx constant_term = const0_rtx;
457 rtx y = eliminate_constant_term (x, &constant_term);
458 if (constant_term == const0_rtx
459 || ! memory_address_p (mode, y))
460 x = force_operand (x, NULL_RTX);
461 else
462 {
463 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
464 if (! memory_address_p (mode, y))
465 x = force_operand (x, NULL_RTX);
466 else
467 x = y;
468 }
469 }
470
471 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
472 x = force_operand (x, NULL_RTX);
473
474 /* If we have a register that's an invalid address,
475 it must be a hard reg of the wrong class. Copy it to a pseudo. */
476 else if (REG_P (x))
477 x = copy_to_reg (x);
478
479 /* Last resort: copy the value to a register, since
480 the register is a valid address. */
481 else
482 x = force_reg (Pmode, x);
483
484 goto done;
485
486 win2:
487 x = oldx;
488 win:
489 if (flag_force_addr && ! cse_not_expected && !REG_P (x))
490 {
491 x = force_operand (x, NULL_RTX);
492 x = force_reg (Pmode, x);
493 }
494 }
495
496 done:
497
498 /* If we didn't change the address, we are done. Otherwise, mark
499 a reg as a pointer if we have REG or REG + CONST_INT. */
500 if (oldx == x)
501 return x;
502 else if (REG_P (x))
503 mark_reg_pointer (x, BITS_PER_UNIT);
504 else if (GET_CODE (x) == PLUS
505 && REG_P (XEXP (x, 0))
506 && GET_CODE (XEXP (x, 1)) == CONST_INT)
507 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
508
509 /* OLDX may have been the address on a temporary. Update the address
510 to indicate that X is now used. */
511 update_temp_slot_address (oldx, x);
512
513 return x;
514 }
515
516 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
517
518 rtx
519 memory_address_noforce (enum machine_mode mode, rtx x)
520 {
521 int ambient_force_addr = flag_force_addr;
522 rtx val;
523
524 flag_force_addr = 0;
525 val = memory_address (mode, x);
526 flag_force_addr = ambient_force_addr;
527 return val;
528 }
529
530 /* Convert a mem ref into one with a valid memory address.
531 Pass through anything else unchanged. */
532
533 rtx
534 validize_mem (rtx ref)
535 {
536 if (!MEM_P (ref))
537 return ref;
538 ref = use_anchored_address (ref);
539 if (! (flag_force_addr && CONSTANT_ADDRESS_P (XEXP (ref, 0)))
540 && memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
541 return ref;
542
543 /* Don't alter REF itself, since that is probably a stack slot. */
544 return replace_equiv_address (ref, XEXP (ref, 0));
545 }
546
547 /* If X is a memory reference to a member of an object block, try rewriting
548 it to use an anchor instead. Return the new memory reference on success
549 and the old one on failure. */
550
551 rtx
552 use_anchored_address (rtx x)
553 {
554 rtx base;
555 HOST_WIDE_INT offset;
556
557 if (!flag_section_anchors)
558 return x;
559
560 if (!MEM_P (x))
561 return x;
562
563 /* Split the address into a base and offset. */
564 base = XEXP (x, 0);
565 offset = 0;
566 if (GET_CODE (base) == CONST
567 && GET_CODE (XEXP (base, 0)) == PLUS
568 && GET_CODE (XEXP (XEXP (base, 0), 1)) == CONST_INT)
569 {
570 offset += INTVAL (XEXP (XEXP (base, 0), 1));
571 base = XEXP (XEXP (base, 0), 0);
572 }
573
574 /* Check whether BASE is suitable for anchors. */
575 if (GET_CODE (base) != SYMBOL_REF
576 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base)
577 || SYMBOL_REF_ANCHOR_P (base)
578 || SYMBOL_REF_BLOCK (base) == NULL
579 || !targetm.use_anchors_for_symbol_p (base))
580 return x;
581
582 /* Decide where BASE is going to be. */
583 place_block_symbol (base);
584
585 /* Get the anchor we need to use. */
586 offset += SYMBOL_REF_BLOCK_OFFSET (base);
587 base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset,
588 SYMBOL_REF_TLS_MODEL (base));
589
590 /* Work out the offset from the anchor. */
591 offset -= SYMBOL_REF_BLOCK_OFFSET (base);
592
593 /* If we're going to run a CSE pass, force the anchor into a register.
594 We will then be able to reuse registers for several accesses, if the
595 target costs say that that's worthwhile. */
596 if (!cse_not_expected)
597 base = force_reg (GET_MODE (base), base);
598
599 return replace_equiv_address (x, plus_constant (base, offset));
600 }
601 \f
602 /* Copy the value or contents of X to a new temp reg and return that reg. */
603
604 rtx
605 copy_to_reg (rtx x)
606 {
607 rtx temp = gen_reg_rtx (GET_MODE (x));
608
609 /* If not an operand, must be an address with PLUS and MULT so
610 do the computation. */
611 if (! general_operand (x, VOIDmode))
612 x = force_operand (x, temp);
613
614 if (x != temp)
615 emit_move_insn (temp, x);
616
617 return temp;
618 }
619
620 /* Like copy_to_reg but always give the new register mode Pmode
621 in case X is a constant. */
622
623 rtx
624 copy_addr_to_reg (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 (enum machine_mode mode, rtx x)
634 {
635 rtx temp = gen_reg_rtx (mode);
636
637 /* If not an operand, must be an address with PLUS and MULT so
638 do the computation. */
639 if (! general_operand (x, VOIDmode))
640 x = force_operand (x, temp);
641
642 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode);
643 if (x != temp)
644 emit_move_insn (temp, x);
645 return temp;
646 }
647
648 /* Load X into a register if it is not already one.
649 Use mode MODE for the register.
650 X should be valid for mode MODE, but it may be a constant which
651 is valid for all integer modes; that's why caller must specify MODE.
652
653 The caller must not alter the value in the register we return,
654 since we mark it as a "constant" register. */
655
656 rtx
657 force_reg (enum machine_mode mode, rtx x)
658 {
659 rtx temp, insn, set;
660
661 if (REG_P (x))
662 return x;
663
664 if (general_operand (x, mode))
665 {
666 temp = gen_reg_rtx (mode);
667 insn = emit_move_insn (temp, x);
668 }
669 else
670 {
671 temp = force_operand (x, NULL_RTX);
672 if (REG_P (temp))
673 insn = get_last_insn ();
674 else
675 {
676 rtx temp2 = gen_reg_rtx (mode);
677 insn = emit_move_insn (temp2, temp);
678 temp = temp2;
679 }
680 }
681
682 /* Let optimizers know that TEMP's value never changes
683 and that X can be substituted for it. Don't get confused
684 if INSN set something else (such as a SUBREG of TEMP). */
685 if (CONSTANT_P (x)
686 && (set = single_set (insn)) != 0
687 && SET_DEST (set) == temp
688 && ! rtx_equal_p (x, SET_SRC (set)))
689 set_unique_reg_note (insn, REG_EQUAL, x);
690
691 /* Let optimizers know that TEMP is a pointer, and if so, the
692 known alignment of that pointer. */
693 {
694 unsigned align = 0;
695 if (GET_CODE (x) == SYMBOL_REF)
696 {
697 align = BITS_PER_UNIT;
698 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
699 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
700 }
701 else if (GET_CODE (x) == LABEL_REF)
702 align = BITS_PER_UNIT;
703 else if (GET_CODE (x) == CONST
704 && GET_CODE (XEXP (x, 0)) == PLUS
705 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
706 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT)
707 {
708 rtx s = XEXP (XEXP (x, 0), 0);
709 rtx c = XEXP (XEXP (x, 0), 1);
710 unsigned sa, ca;
711
712 sa = BITS_PER_UNIT;
713 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
714 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
715
716 ca = exact_log2 (INTVAL (c) & -INTVAL (c)) * BITS_PER_UNIT;
717
718 align = MIN (sa, ca);
719 }
720 else if (MEM_P (x) && MEM_POINTER (x))
721 align = MEM_ALIGN (x);
722
723 if (align)
724 mark_reg_pointer (temp, align);
725 }
726
727 return temp;
728 }
729
730 /* If X is a memory ref, copy its contents to a new temp reg and return
731 that reg. Otherwise, return X. */
732
733 rtx
734 force_not_mem (rtx x)
735 {
736 rtx temp;
737
738 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
739 return x;
740
741 temp = gen_reg_rtx (GET_MODE (x));
742
743 if (MEM_POINTER (x))
744 REG_POINTER (temp) = 1;
745
746 emit_move_insn (temp, x);
747 return temp;
748 }
749
750 /* Copy X to TARGET (if it's nonzero and a reg)
751 or to a new temp reg and return that reg.
752 MODE is the mode to use for X in case it is a constant. */
753
754 rtx
755 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode)
756 {
757 rtx temp;
758
759 if (target && REG_P (target))
760 temp = target;
761 else
762 temp = gen_reg_rtx (mode);
763
764 emit_move_insn (temp, x);
765 return temp;
766 }
767 \f
768 /* Return the mode to use to store a scalar of TYPE and MODE.
769 PUNSIGNEDP points to the signedness of the type and may be adjusted
770 to show what signedness to use on extension operations.
771
772 FOR_CALL is nonzero if this call is promoting args for a call. */
773
774 #if defined(PROMOTE_MODE) && !defined(PROMOTE_FUNCTION_MODE)
775 #define PROMOTE_FUNCTION_MODE PROMOTE_MODE
776 #endif
777
778 enum machine_mode
779 promote_mode (tree type, enum machine_mode mode, int *punsignedp,
780 int for_call ATTRIBUTE_UNUSED)
781 {
782 enum tree_code code = TREE_CODE (type);
783 int unsignedp = *punsignedp;
784
785 #ifndef PROMOTE_MODE
786 if (! for_call)
787 return mode;
788 #endif
789
790 switch (code)
791 {
792 #ifdef PROMOTE_FUNCTION_MODE
793 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
794 case REAL_TYPE: case OFFSET_TYPE:
795 #ifdef PROMOTE_MODE
796 if (for_call)
797 {
798 #endif
799 PROMOTE_FUNCTION_MODE (mode, unsignedp, type);
800 #ifdef PROMOTE_MODE
801 }
802 else
803 {
804 PROMOTE_MODE (mode, unsignedp, type);
805 }
806 #endif
807 break;
808 #endif
809
810 #ifdef POINTERS_EXTEND_UNSIGNED
811 case REFERENCE_TYPE:
812 case POINTER_TYPE:
813 mode = Pmode;
814 unsignedp = POINTERS_EXTEND_UNSIGNED;
815 break;
816 #endif
817
818 default:
819 break;
820 }
821
822 *punsignedp = unsignedp;
823 return mode;
824 }
825 \f
826 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
827 This pops when ADJUST is positive. ADJUST need not be constant. */
828
829 void
830 adjust_stack (rtx adjust)
831 {
832 rtx temp;
833
834 if (adjust == const0_rtx)
835 return;
836
837 /* We expect all variable sized adjustments to be multiple of
838 PREFERRED_STACK_BOUNDARY. */
839 if (GET_CODE (adjust) == CONST_INT)
840 stack_pointer_delta -= INTVAL (adjust);
841
842 temp = expand_binop (Pmode,
843 #ifdef STACK_GROWS_DOWNWARD
844 add_optab,
845 #else
846 sub_optab,
847 #endif
848 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
849 OPTAB_LIB_WIDEN);
850
851 if (temp != stack_pointer_rtx)
852 emit_move_insn (stack_pointer_rtx, temp);
853 }
854
855 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
856 This pushes when ADJUST is positive. ADJUST need not be constant. */
857
858 void
859 anti_adjust_stack (rtx adjust)
860 {
861 rtx temp;
862
863 if (adjust == const0_rtx)
864 return;
865
866 /* We expect all variable sized adjustments to be multiple of
867 PREFERRED_STACK_BOUNDARY. */
868 if (GET_CODE (adjust) == CONST_INT)
869 stack_pointer_delta += INTVAL (adjust);
870
871 temp = expand_binop (Pmode,
872 #ifdef STACK_GROWS_DOWNWARD
873 sub_optab,
874 #else
875 add_optab,
876 #endif
877 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
878 OPTAB_LIB_WIDEN);
879
880 if (temp != stack_pointer_rtx)
881 emit_move_insn (stack_pointer_rtx, temp);
882 }
883
884 /* Round the size of a block to be pushed up to the boundary required
885 by this machine. SIZE is the desired size, which need not be constant. */
886
887 static rtx
888 round_push (rtx size)
889 {
890 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
891
892 if (align == 1)
893 return size;
894
895 if (GET_CODE (size) == CONST_INT)
896 {
897 HOST_WIDE_INT new = (INTVAL (size) + align - 1) / align * align;
898
899 if (INTVAL (size) != new)
900 size = GEN_INT (new);
901 }
902 else
903 {
904 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
905 but we know it can't. So add ourselves and then do
906 TRUNC_DIV_EXPR. */
907 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
908 NULL_RTX, 1, OPTAB_LIB_WIDEN);
909 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
910 NULL_RTX, 1);
911 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
912 }
913
914 return size;
915 }
916 \f
917 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
918 to a previously-created save area. If no save area has been allocated,
919 this function will allocate one. If a save area is specified, it
920 must be of the proper mode.
921
922 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
923 are emitted at the current position. */
924
925 void
926 emit_stack_save (enum save_level save_level, rtx *psave, rtx after)
927 {
928 rtx sa = *psave;
929 /* The default is that we use a move insn and save in a Pmode object. */
930 rtx (*fcn) (rtx, rtx) = gen_move_insn;
931 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
932
933 /* See if this machine has anything special to do for this kind of save. */
934 switch (save_level)
935 {
936 #ifdef HAVE_save_stack_block
937 case SAVE_BLOCK:
938 if (HAVE_save_stack_block)
939 fcn = gen_save_stack_block;
940 break;
941 #endif
942 #ifdef HAVE_save_stack_function
943 case SAVE_FUNCTION:
944 if (HAVE_save_stack_function)
945 fcn = gen_save_stack_function;
946 break;
947 #endif
948 #ifdef HAVE_save_stack_nonlocal
949 case SAVE_NONLOCAL:
950 if (HAVE_save_stack_nonlocal)
951 fcn = gen_save_stack_nonlocal;
952 break;
953 #endif
954 default:
955 break;
956 }
957
958 /* If there is no save area and we have to allocate one, do so. Otherwise
959 verify the save area is the proper mode. */
960
961 if (sa == 0)
962 {
963 if (mode != VOIDmode)
964 {
965 if (save_level == SAVE_NONLOCAL)
966 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
967 else
968 *psave = sa = gen_reg_rtx (mode);
969 }
970 }
971
972 if (after)
973 {
974 rtx seq;
975
976 start_sequence ();
977 do_pending_stack_adjust ();
978 /* We must validize inside the sequence, to ensure that any instructions
979 created by the validize call also get moved to the right place. */
980 if (sa != 0)
981 sa = validize_mem (sa);
982 emit_insn (fcn (sa, stack_pointer_rtx));
983 seq = get_insns ();
984 end_sequence ();
985 emit_insn_after (seq, after);
986 }
987 else
988 {
989 do_pending_stack_adjust ();
990 if (sa != 0)
991 sa = validize_mem (sa);
992 emit_insn (fcn (sa, stack_pointer_rtx));
993 }
994 }
995
996 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
997 area made by emit_stack_save. If it is zero, we have nothing to do.
998
999 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1000 current position. */
1001
1002 void
1003 emit_stack_restore (enum save_level save_level, rtx sa, rtx after)
1004 {
1005 /* The default is that we use a move insn. */
1006 rtx (*fcn) (rtx, rtx) = gen_move_insn;
1007
1008 /* See if this machine has anything special to do for this kind of save. */
1009 switch (save_level)
1010 {
1011 #ifdef HAVE_restore_stack_block
1012 case SAVE_BLOCK:
1013 if (HAVE_restore_stack_block)
1014 fcn = gen_restore_stack_block;
1015 break;
1016 #endif
1017 #ifdef HAVE_restore_stack_function
1018 case SAVE_FUNCTION:
1019 if (HAVE_restore_stack_function)
1020 fcn = gen_restore_stack_function;
1021 break;
1022 #endif
1023 #ifdef HAVE_restore_stack_nonlocal
1024 case SAVE_NONLOCAL:
1025 if (HAVE_restore_stack_nonlocal)
1026 fcn = gen_restore_stack_nonlocal;
1027 break;
1028 #endif
1029 default:
1030 break;
1031 }
1032
1033 if (sa != 0)
1034 {
1035 sa = validize_mem (sa);
1036 /* These clobbers prevent the scheduler from moving
1037 references to variable arrays below the code
1038 that deletes (pops) the arrays. */
1039 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1040 gen_rtx_MEM (BLKmode,
1041 gen_rtx_SCRATCH (VOIDmode))));
1042 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1043 gen_rtx_MEM (BLKmode, stack_pointer_rtx)));
1044 }
1045
1046 discard_pending_stack_adjust ();
1047
1048 if (after)
1049 {
1050 rtx seq;
1051
1052 start_sequence ();
1053 emit_insn (fcn (stack_pointer_rtx, sa));
1054 seq = get_insns ();
1055 end_sequence ();
1056 emit_insn_after (seq, after);
1057 }
1058 else
1059 emit_insn (fcn (stack_pointer_rtx, sa));
1060 }
1061
1062 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1063 function. This function should be called whenever we allocate or
1064 deallocate dynamic stack space. */
1065
1066 void
1067 update_nonlocal_goto_save_area (void)
1068 {
1069 tree t_save;
1070 rtx r_save;
1071
1072 /* The nonlocal_goto_save_area object is an array of N pointers. The
1073 first one is used for the frame pointer save; the rest are sized by
1074 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1075 of the stack save area slots. */
1076 t_save = build4 (ARRAY_REF, ptr_type_node, cfun->nonlocal_goto_save_area,
1077 integer_one_node, NULL_TREE, NULL_TREE);
1078 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1079
1080 emit_stack_save (SAVE_NONLOCAL, &r_save, NULL_RTX);
1081 }
1082 \f
1083 /* Return an rtx representing the address of an area of memory dynamically
1084 pushed on the stack. This region of memory is always aligned to
1085 a multiple of BIGGEST_ALIGNMENT.
1086
1087 Any required stack pointer alignment is preserved.
1088
1089 SIZE is an rtx representing the size of the area.
1090 TARGET is a place in which the address can be placed.
1091
1092 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1093
1094 rtx
1095 allocate_dynamic_stack_space (rtx size, rtx target, int known_align)
1096 {
1097 /* If we're asking for zero bytes, it doesn't matter what we point
1098 to since we can't dereference it. But return a reasonable
1099 address anyway. */
1100 if (size == const0_rtx)
1101 return virtual_stack_dynamic_rtx;
1102
1103 /* Otherwise, show we're calling alloca or equivalent. */
1104 current_function_calls_alloca = 1;
1105
1106 /* Ensure the size is in the proper mode. */
1107 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1108 size = convert_to_mode (Pmode, size, 1);
1109
1110 /* We can't attempt to minimize alignment necessary, because we don't
1111 know the final value of preferred_stack_boundary yet while executing
1112 this code. */
1113 cfun->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1114
1115 /* We will need to ensure that the address we return is aligned to
1116 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1117 always know its final value at this point in the compilation (it
1118 might depend on the size of the outgoing parameter lists, for
1119 example), so we must align the value to be returned in that case.
1120 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1121 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1122 We must also do an alignment operation on the returned value if
1123 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1124
1125 If we have to align, we must leave space in SIZE for the hole
1126 that might result from the alignment operation. */
1127
1128 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1129 #define MUST_ALIGN 1
1130 #else
1131 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1132 #endif
1133
1134 if (MUST_ALIGN)
1135 size
1136 = force_operand (plus_constant (size,
1137 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1138 NULL_RTX);
1139
1140 #ifdef SETJMP_VIA_SAVE_AREA
1141 /* If setjmp restores regs from a save area in the stack frame,
1142 avoid clobbering the reg save area. Note that the offset of
1143 virtual_incoming_args_rtx includes the preallocated stack args space.
1144 It would be no problem to clobber that, but it's on the wrong side
1145 of the old save area.
1146
1147 What used to happen is that, since we did not know for sure
1148 whether setjmp() was invoked until after RTL generation, we
1149 would use reg notes to store the "optimized" size and fix things
1150 up later. These days we know this information before we ever
1151 start building RTL so the reg notes are unnecessary. */
1152 if (!current_function_calls_setjmp)
1153 {
1154 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1155
1156 /* ??? Code below assumes that the save area needs maximal
1157 alignment. This constraint may be too strong. */
1158 gcc_assert (PREFERRED_STACK_BOUNDARY == BIGGEST_ALIGNMENT);
1159
1160 if (GET_CODE (size) == CONST_INT)
1161 {
1162 HOST_WIDE_INT new = INTVAL (size) / align * align;
1163
1164 if (INTVAL (size) != new)
1165 size = GEN_INT (new);
1166 }
1167 else
1168 {
1169 /* Since we know overflow is not possible, we avoid using
1170 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1171 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1172 GEN_INT (align), NULL_RTX, 1);
1173 size = expand_mult (Pmode, size,
1174 GEN_INT (align), NULL_RTX, 1);
1175 }
1176 }
1177 else
1178 {
1179 rtx dynamic_offset
1180 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1181 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1182
1183 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1184 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1185 }
1186 #endif /* SETJMP_VIA_SAVE_AREA */
1187
1188 /* Round the size to a multiple of the required stack alignment.
1189 Since the stack if presumed to be rounded before this allocation,
1190 this will maintain the required alignment.
1191
1192 If the stack grows downward, we could save an insn by subtracting
1193 SIZE from the stack pointer and then aligning the stack pointer.
1194 The problem with this is that the stack pointer may be unaligned
1195 between the execution of the subtraction and alignment insns and
1196 some machines do not allow this. Even on those that do, some
1197 signal handlers malfunction if a signal should occur between those
1198 insns. Since this is an extremely rare event, we have no reliable
1199 way of knowing which systems have this problem. So we avoid even
1200 momentarily mis-aligning the stack. */
1201
1202 /* If we added a variable amount to SIZE,
1203 we can no longer assume it is aligned. */
1204 #if !defined (SETJMP_VIA_SAVE_AREA)
1205 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1206 #endif
1207 size = round_push (size);
1208
1209 do_pending_stack_adjust ();
1210
1211 /* We ought to be called always on the toplevel and stack ought to be aligned
1212 properly. */
1213 gcc_assert (!(stack_pointer_delta
1214 % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)));
1215
1216 /* If needed, check that we have the required amount of stack. Take into
1217 account what has already been checked. */
1218 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1219 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1220
1221 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1222 if (target == 0 || !REG_P (target)
1223 || REGNO (target) < FIRST_PSEUDO_REGISTER
1224 || GET_MODE (target) != Pmode)
1225 target = gen_reg_rtx (Pmode);
1226
1227 mark_reg_pointer (target, known_align);
1228
1229 /* Perform the required allocation from the stack. Some systems do
1230 this differently than simply incrementing/decrementing from the
1231 stack pointer, such as acquiring the space by calling malloc(). */
1232 #ifdef HAVE_allocate_stack
1233 if (HAVE_allocate_stack)
1234 {
1235 enum machine_mode mode = STACK_SIZE_MODE;
1236 insn_operand_predicate_fn pred;
1237
1238 /* We don't have to check against the predicate for operand 0 since
1239 TARGET is known to be a pseudo of the proper mode, which must
1240 be valid for the operand. For operand 1, convert to the
1241 proper mode and validate. */
1242 if (mode == VOIDmode)
1243 mode = insn_data[(int) CODE_FOR_allocate_stack].operand[1].mode;
1244
1245 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1246 if (pred && ! ((*pred) (size, mode)))
1247 size = copy_to_mode_reg (mode, convert_to_mode (mode, size, 1));
1248
1249 emit_insn (gen_allocate_stack (target, size));
1250 }
1251 else
1252 #endif
1253 {
1254 #ifndef STACK_GROWS_DOWNWARD
1255 emit_move_insn (target, virtual_stack_dynamic_rtx);
1256 #endif
1257
1258 /* Check stack bounds if necessary. */
1259 if (current_function_limit_stack)
1260 {
1261 rtx available;
1262 rtx space_available = gen_label_rtx ();
1263 #ifdef STACK_GROWS_DOWNWARD
1264 available = expand_binop (Pmode, sub_optab,
1265 stack_pointer_rtx, stack_limit_rtx,
1266 NULL_RTX, 1, OPTAB_WIDEN);
1267 #else
1268 available = expand_binop (Pmode, sub_optab,
1269 stack_limit_rtx, stack_pointer_rtx,
1270 NULL_RTX, 1, OPTAB_WIDEN);
1271 #endif
1272 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1273 space_available);
1274 #ifdef HAVE_trap
1275 if (HAVE_trap)
1276 emit_insn (gen_trap ());
1277 else
1278 #endif
1279 error ("stack limits not supported on this target");
1280 emit_barrier ();
1281 emit_label (space_available);
1282 }
1283
1284 anti_adjust_stack (size);
1285
1286 #ifdef STACK_GROWS_DOWNWARD
1287 emit_move_insn (target, virtual_stack_dynamic_rtx);
1288 #endif
1289 }
1290
1291 if (MUST_ALIGN)
1292 {
1293 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1294 but we know it can't. So add ourselves and then do
1295 TRUNC_DIV_EXPR. */
1296 target = expand_binop (Pmode, add_optab, target,
1297 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1298 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1299 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1300 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1301 NULL_RTX, 1);
1302 target = expand_mult (Pmode, target,
1303 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1304 NULL_RTX, 1);
1305 }
1306
1307 /* Record the new stack level for nonlocal gotos. */
1308 if (cfun->nonlocal_goto_save_area != 0)
1309 update_nonlocal_goto_save_area ();
1310
1311 return target;
1312 }
1313 \f
1314 /* A front end may want to override GCC's stack checking by providing a
1315 run-time routine to call to check the stack, so provide a mechanism for
1316 calling that routine. */
1317
1318 static GTY(()) rtx stack_check_libfunc;
1319
1320 void
1321 set_stack_check_libfunc (rtx libfunc)
1322 {
1323 stack_check_libfunc = libfunc;
1324 }
1325 \f
1326 /* Emit one stack probe at ADDRESS, an address within the stack. */
1327
1328 static void
1329 emit_stack_probe (rtx address)
1330 {
1331 rtx memref = gen_rtx_MEM (word_mode, address);
1332
1333 MEM_VOLATILE_P (memref) = 1;
1334
1335 if (STACK_CHECK_PROBE_LOAD)
1336 emit_move_insn (gen_reg_rtx (word_mode), memref);
1337 else
1338 emit_move_insn (memref, const0_rtx);
1339 }
1340
1341 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1342 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1343 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1344 subtract from the stack. If SIZE is constant, this is done
1345 with a fixed number of probes. Otherwise, we must make a loop. */
1346
1347 #ifdef STACK_GROWS_DOWNWARD
1348 #define STACK_GROW_OP MINUS
1349 #else
1350 #define STACK_GROW_OP PLUS
1351 #endif
1352
1353 void
1354 probe_stack_range (HOST_WIDE_INT first, rtx size)
1355 {
1356 /* First ensure SIZE is Pmode. */
1357 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1358 size = convert_to_mode (Pmode, size, 1);
1359
1360 /* Next see if the front end has set up a function for us to call to
1361 check the stack. */
1362 if (stack_check_libfunc != 0)
1363 {
1364 rtx addr = memory_address (QImode,
1365 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1366 stack_pointer_rtx,
1367 plus_constant (size, first)));
1368
1369 addr = convert_memory_address (ptr_mode, addr);
1370 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1371 ptr_mode);
1372 }
1373
1374 /* Next see if we have an insn to check the stack. Use it if so. */
1375 #ifdef HAVE_check_stack
1376 else if (HAVE_check_stack)
1377 {
1378 insn_operand_predicate_fn pred;
1379 rtx last_addr
1380 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1381 stack_pointer_rtx,
1382 plus_constant (size, first)),
1383 NULL_RTX);
1384
1385 pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1386 if (pred && ! ((*pred) (last_addr, Pmode)))
1387 last_addr = copy_to_mode_reg (Pmode, last_addr);
1388
1389 emit_insn (gen_check_stack (last_addr));
1390 }
1391 #endif
1392
1393 /* If we have to generate explicit probes, see if we have a constant
1394 small number of them to generate. If so, that's the easy case. */
1395 else if (GET_CODE (size) == CONST_INT
1396 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1397 {
1398 HOST_WIDE_INT offset;
1399
1400 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1401 for values of N from 1 until it exceeds LAST. If only one
1402 probe is needed, this will not generate any code. Then probe
1403 at LAST. */
1404 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1405 offset < INTVAL (size);
1406 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1407 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1408 stack_pointer_rtx,
1409 GEN_INT (offset)));
1410
1411 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1412 stack_pointer_rtx,
1413 plus_constant (size, first)));
1414 }
1415
1416 /* In the variable case, do the same as above, but in a loop. We emit loop
1417 notes so that loop optimization can be done. */
1418 else
1419 {
1420 rtx test_addr
1421 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1422 stack_pointer_rtx,
1423 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1424 NULL_RTX);
1425 rtx last_addr
1426 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1427 stack_pointer_rtx,
1428 plus_constant (size, first)),
1429 NULL_RTX);
1430 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1431 rtx loop_lab = gen_label_rtx ();
1432 rtx test_lab = gen_label_rtx ();
1433 rtx end_lab = gen_label_rtx ();
1434 rtx temp;
1435
1436 if (!REG_P (test_addr)
1437 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1438 test_addr = force_reg (Pmode, test_addr);
1439
1440 emit_jump (test_lab);
1441
1442 emit_label (loop_lab);
1443 emit_stack_probe (test_addr);
1444
1445 #ifdef STACK_GROWS_DOWNWARD
1446 #define CMP_OPCODE GTU
1447 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1448 1, OPTAB_WIDEN);
1449 #else
1450 #define CMP_OPCODE LTU
1451 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1452 1, OPTAB_WIDEN);
1453 #endif
1454
1455 gcc_assert (temp == test_addr);
1456
1457 emit_label (test_lab);
1458 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1459 NULL_RTX, Pmode, 1, loop_lab);
1460 emit_jump (end_lab);
1461 emit_label (end_lab);
1462
1463 emit_stack_probe (last_addr);
1464 }
1465 }
1466 \f
1467 /* Return an rtx representing the register or memory location
1468 in which a scalar value of data type VALTYPE
1469 was returned by a function call to function FUNC.
1470 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1471 function is known, otherwise 0.
1472 OUTGOING is 1 if on a machine with register windows this function
1473 should return the register in which the function will put its result
1474 and 0 otherwise. */
1475
1476 rtx
1477 hard_function_value (tree valtype, tree func, tree fntype,
1478 int outgoing ATTRIBUTE_UNUSED)
1479 {
1480 rtx val;
1481
1482 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing);
1483
1484 if (REG_P (val)
1485 && GET_MODE (val) == BLKmode)
1486 {
1487 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1488 enum machine_mode tmpmode;
1489
1490 /* int_size_in_bytes can return -1. We don't need a check here
1491 since the value of bytes will then be large enough that no
1492 mode will match anyway. */
1493
1494 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1495 tmpmode != VOIDmode;
1496 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1497 {
1498 /* Have we found a large enough mode? */
1499 if (GET_MODE_SIZE (tmpmode) >= bytes)
1500 break;
1501 }
1502
1503 /* No suitable mode found. */
1504 gcc_assert (tmpmode != VOIDmode);
1505
1506 PUT_MODE (val, tmpmode);
1507 }
1508 return val;
1509 }
1510
1511 /* Return an rtx representing the register or memory location
1512 in which a scalar value of mode MODE was returned by a library call. */
1513
1514 rtx
1515 hard_libcall_value (enum machine_mode mode)
1516 {
1517 return LIBCALL_VALUE (mode);
1518 }
1519
1520 /* Look up the tree code for a given rtx code
1521 to provide the arithmetic operation for REAL_ARITHMETIC.
1522 The function returns an int because the caller may not know
1523 what `enum tree_code' means. */
1524
1525 int
1526 rtx_to_tree_code (enum rtx_code code)
1527 {
1528 enum tree_code tcode;
1529
1530 switch (code)
1531 {
1532 case PLUS:
1533 tcode = PLUS_EXPR;
1534 break;
1535 case MINUS:
1536 tcode = MINUS_EXPR;
1537 break;
1538 case MULT:
1539 tcode = MULT_EXPR;
1540 break;
1541 case DIV:
1542 tcode = RDIV_EXPR;
1543 break;
1544 case SMIN:
1545 tcode = MIN_EXPR;
1546 break;
1547 case SMAX:
1548 tcode = MAX_EXPR;
1549 break;
1550 default:
1551 tcode = LAST_AND_UNUSED_TREE_CODE;
1552 break;
1553 }
1554 return ((int) tcode);
1555 }
1556
1557 #include "gt-explow.h"