2000-05-02 Jeff Sturm <jsturm@one-point.com>
[official-gcc.git] / gcc / explow.c
blob171670b3374535acfeb88d9d5b3d15bf9037d83a
1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987, 1991, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
10 any later version.
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 #include "config.h"
24 #include "system.h"
25 #include "toplev.h"
26 #include "rtl.h"
27 #include "tree.h"
28 #include "tm_p.h"
29 #include "flags.h"
30 #include "function.h"
31 #include "expr.h"
32 #include "hard-reg-set.h"
33 #include "insn-config.h"
34 #include "recog.h"
36 #if !defined PREFERRED_STACK_BOUNDARY && defined STACK_BOUNDARY
37 #define PREFERRED_STACK_BOUNDARY STACK_BOUNDARY
38 #endif
40 static rtx break_out_memory_refs PARAMS ((rtx));
41 static void emit_stack_probe PARAMS ((rtx));
44 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
46 HOST_WIDE_INT
47 trunc_int_for_mode (c, mode)
48 HOST_WIDE_INT c;
49 enum machine_mode mode;
51 int width = GET_MODE_BITSIZE (mode);
53 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
54 if (mode == BImode)
55 return c & 1 ? STORE_FLAG_VALUE : 0;
57 /* Sign-extend for the requested mode. */
59 if (width < HOST_BITS_PER_WIDE_INT)
61 HOST_WIDE_INT sign = 1;
62 sign <<= width - 1;
63 c &= (sign << 1) - 1;
64 c ^= sign;
65 c -= sign;
68 return c;
71 /* Return an rtx for the sum of X and the integer C.
73 This function should be used via the `plus_constant' macro. */
75 rtx
76 plus_constant_wide (x, c)
77 register rtx x;
78 register HOST_WIDE_INT c;
80 register RTX_CODE code;
81 register enum machine_mode mode;
82 register rtx tem;
83 int all_constant = 0;
85 if (c == 0)
86 return x;
88 restart:
90 code = GET_CODE (x);
91 mode = GET_MODE (x);
92 switch (code)
94 case CONST_INT:
95 return GEN_INT (INTVAL (x) + c);
97 case CONST_DOUBLE:
99 unsigned HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
100 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
101 unsigned HOST_WIDE_INT l2 = c;
102 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
103 unsigned HOST_WIDE_INT lv;
104 HOST_WIDE_INT hv;
106 add_double (l1, h1, l2, h2, &lv, &hv);
108 return immed_double_const (lv, hv, VOIDmode);
111 case MEM:
112 /* If this is a reference to the constant pool, try replacing it with
113 a reference to a new constant. If the resulting address isn't
114 valid, don't return it because we have no way to validize it. */
115 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
116 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
119 = force_const_mem (GET_MODE (x),
120 plus_constant (get_pool_constant (XEXP (x, 0)),
121 c));
122 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
123 return tem;
125 break;
127 case CONST:
128 /* If adding to something entirely constant, set a flag
129 so that we can add a CONST around the result. */
130 x = XEXP (x, 0);
131 all_constant = 1;
132 goto restart;
134 case SYMBOL_REF:
135 case LABEL_REF:
136 all_constant = 1;
137 break;
139 case PLUS:
140 /* The interesting case is adding the integer to a sum.
141 Look for constant term in the sum and combine
142 with C. For an integer constant term, we make a combined
143 integer. For a constant term that is not an explicit integer,
144 we cannot really combine, but group them together anyway.
146 Restart or use a recursive call in case the remaining operand is
147 something that we handle specially, such as a SYMBOL_REF.
149 We may not immediately return from the recursive call here, lest
150 all_constant gets lost. */
152 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
154 c += INTVAL (XEXP (x, 1));
156 if (GET_MODE (x) != VOIDmode)
157 c = trunc_int_for_mode (c, GET_MODE (x));
159 x = XEXP (x, 0);
160 goto restart;
162 else if (CONSTANT_P (XEXP (x, 0)))
164 x = gen_rtx_PLUS (mode,
165 plus_constant (XEXP (x, 0), c),
166 XEXP (x, 1));
167 c = 0;
169 else if (CONSTANT_P (XEXP (x, 1)))
171 x = gen_rtx_PLUS (mode,
172 XEXP (x, 0),
173 plus_constant (XEXP (x, 1), c));
174 c = 0;
176 break;
178 default:
179 break;
182 if (c != 0)
183 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
185 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
186 return x;
187 else if (all_constant)
188 return gen_rtx_CONST (mode, x);
189 else
190 return x;
193 /* This is the same as `plus_constant', except that it handles LO_SUM.
195 This function should be used via the `plus_constant_for_output' macro. */
198 plus_constant_for_output_wide (x, c)
199 register rtx x;
200 register HOST_WIDE_INT c;
202 register enum machine_mode mode = GET_MODE (x);
204 if (GET_CODE (x) == LO_SUM)
205 return gen_rtx_LO_SUM (mode, XEXP (x, 0),
206 plus_constant_for_output (XEXP (x, 1), c));
208 else
209 return plus_constant (x, c);
212 /* If X is a sum, return a new sum like X but lacking any constant terms.
213 Add all the removed constant terms into *CONSTPTR.
214 X itself is not altered. The result != X if and only if
215 it is not isomorphic to X. */
218 eliminate_constant_term (x, constptr)
219 rtx x;
220 rtx *constptr;
222 register rtx x0, x1;
223 rtx tem;
225 if (GET_CODE (x) != PLUS)
226 return x;
228 /* First handle constants appearing at this level explicitly. */
229 if (GET_CODE (XEXP (x, 1)) == CONST_INT
230 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
231 XEXP (x, 1)))
232 && GET_CODE (tem) == CONST_INT)
234 *constptr = tem;
235 return eliminate_constant_term (XEXP (x, 0), constptr);
238 tem = const0_rtx;
239 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
240 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
241 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
242 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
243 *constptr, tem))
244 && GET_CODE (tem) == CONST_INT)
246 *constptr = tem;
247 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
250 return x;
253 /* Returns the insn that next references REG after INSN, or 0
254 if REG is clobbered before next referenced or we cannot find
255 an insn that references REG in a straight-line piece of code. */
258 find_next_ref (reg, insn)
259 rtx reg;
260 rtx insn;
262 rtx next;
264 for (insn = NEXT_INSN (insn); insn; insn = next)
266 next = NEXT_INSN (insn);
267 if (GET_CODE (insn) == NOTE)
268 continue;
269 if (GET_CODE (insn) == CODE_LABEL
270 || GET_CODE (insn) == BARRIER)
271 return 0;
272 if (GET_CODE (insn) == INSN
273 || GET_CODE (insn) == JUMP_INSN
274 || GET_CODE (insn) == CALL_INSN)
276 if (reg_set_p (reg, insn))
277 return 0;
278 if (reg_mentioned_p (reg, PATTERN (insn)))
279 return insn;
280 if (GET_CODE (insn) == JUMP_INSN)
282 if (any_uncondjump_p (insn))
283 next = JUMP_LABEL (insn);
284 else
285 return 0;
287 if (GET_CODE (insn) == CALL_INSN
288 && REGNO (reg) < FIRST_PSEUDO_REGISTER
289 && call_used_regs[REGNO (reg)])
290 return 0;
292 else
293 abort ();
295 return 0;
298 /* Return an rtx for the size in bytes of the value of EXP. */
301 expr_size (exp)
302 tree exp;
304 tree size = size_in_bytes (TREE_TYPE (exp));
306 if (TREE_CODE (size) != INTEGER_CST
307 && contains_placeholder_p (size))
308 size = build (WITH_RECORD_EXPR, sizetype, size, exp);
310 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype),
311 EXPAND_MEMORY_USE_BAD);
314 /* Return a copy of X in which all memory references
315 and all constants that involve symbol refs
316 have been replaced with new temporary registers.
317 Also emit code to load the memory locations and constants
318 into those registers.
320 If X contains no such constants or memory references,
321 X itself (not a copy) is returned.
323 If a constant is found in the address that is not a legitimate constant
324 in an insn, it is left alone in the hope that it might be valid in the
325 address.
327 X may contain no arithmetic except addition, subtraction and multiplication.
328 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
330 static rtx
331 break_out_memory_refs (x)
332 register rtx x;
334 if (GET_CODE (x) == MEM
335 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
336 && GET_MODE (x) != VOIDmode))
337 x = force_reg (GET_MODE (x), x);
338 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
339 || GET_CODE (x) == MULT)
341 register rtx op0 = break_out_memory_refs (XEXP (x, 0));
342 register rtx op1 = break_out_memory_refs (XEXP (x, 1));
344 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
345 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
348 return x;
351 #ifdef POINTERS_EXTEND_UNSIGNED
353 /* Given X, a memory address in ptr_mode, convert it to an address
354 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
355 the fact that pointers are not allowed to overflow by commuting arithmetic
356 operations over conversions so that address arithmetic insns can be
357 used. */
360 convert_memory_address (to_mode, x)
361 enum machine_mode to_mode;
362 rtx x;
364 enum machine_mode from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
365 rtx temp;
367 /* Here we handle some special cases. If none of them apply, fall through
368 to the default case. */
369 switch (GET_CODE (x))
371 case CONST_INT:
372 case CONST_DOUBLE:
373 return x;
375 case SUBREG:
376 if (GET_MODE (SUBREG_REG (x)) == to_mode)
377 return SUBREG_REG (x);
378 break;
380 case LABEL_REF:
381 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
382 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
383 return temp;
385 case SYMBOL_REF:
386 temp = gen_rtx_SYMBOL_REF (to_mode, XSTR (x, 0));
387 SYMBOL_REF_FLAG (temp) = SYMBOL_REF_FLAG (x);
388 CONSTANT_POOL_ADDRESS_P (temp) = CONSTANT_POOL_ADDRESS_P (x);
389 STRING_POOL_ADDRESS_P (temp) = STRING_POOL_ADDRESS_P (x);
390 return temp;
392 case CONST:
393 return gen_rtx_CONST (to_mode,
394 convert_memory_address (to_mode, XEXP (x, 0)));
396 case PLUS:
397 case MULT:
398 /* For addition the second operand is a small constant, we can safely
399 permute the conversion and addition operation. We can always safely
400 permute them if we are making the address narrower. In addition,
401 always permute the operations if this is a constant. */
402 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
403 || (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 1)) == CONST_INT
404 && (INTVAL (XEXP (x, 1)) + 20000 < 40000
405 || CONSTANT_P (XEXP (x, 0)))))
406 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
407 convert_memory_address (to_mode, XEXP (x, 0)),
408 convert_memory_address (to_mode, XEXP (x, 1)));
409 break;
411 default:
412 break;
415 return convert_modes (to_mode, from_mode,
416 x, POINTERS_EXTEND_UNSIGNED);
418 #endif
420 /* Given a memory address or facsimile X, construct a new address,
421 currently equivalent, that is stable: future stores won't change it.
423 X must be composed of constants, register and memory references
424 combined with addition, subtraction and multiplication:
425 in other words, just what you can get from expand_expr if sum_ok is 1.
427 Works by making copies of all regs and memory locations used
428 by X and combining them the same way X does.
429 You could also stabilize the reference to this address
430 by copying the address to a register with copy_to_reg;
431 but then you wouldn't get indexed addressing in the reference. */
434 copy_all_regs (x)
435 register rtx x;
437 if (GET_CODE (x) == REG)
439 if (REGNO (x) != FRAME_POINTER_REGNUM
440 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
441 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
442 #endif
444 x = copy_to_reg (x);
446 else if (GET_CODE (x) == MEM)
447 x = copy_to_reg (x);
448 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
449 || GET_CODE (x) == MULT)
451 register rtx op0 = copy_all_regs (XEXP (x, 0));
452 register rtx op1 = copy_all_regs (XEXP (x, 1));
453 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
454 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
456 return x;
459 /* Return something equivalent to X but valid as a memory address
460 for something of mode MODE. When X is not itself valid, this
461 works by copying X or subexpressions of it into registers. */
464 memory_address (mode, x)
465 enum machine_mode mode;
466 register rtx x;
468 register rtx oldx = x;
470 if (GET_CODE (x) == ADDRESSOF)
471 return x;
473 #ifdef POINTERS_EXTEND_UNSIGNED
474 if (GET_MODE (x) == ptr_mode)
475 x = convert_memory_address (Pmode, x);
476 #endif
478 /* By passing constant addresses thru registers
479 we get a chance to cse them. */
480 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
481 x = force_reg (Pmode, x);
483 /* Accept a QUEUED that refers to a REG
484 even though that isn't a valid address.
485 On attempting to put this in an insn we will call protect_from_queue
486 which will turn it into a REG, which is valid. */
487 else if (GET_CODE (x) == QUEUED
488 && GET_CODE (QUEUED_VAR (x)) == REG)
491 /* We get better cse by rejecting indirect addressing at this stage.
492 Let the combiner create indirect addresses where appropriate.
493 For now, generate the code so that the subexpressions useful to share
494 are visible. But not if cse won't be done! */
495 else
497 if (! cse_not_expected && GET_CODE (x) != REG)
498 x = break_out_memory_refs (x);
500 /* At this point, any valid address is accepted. */
501 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
503 /* If it was valid before but breaking out memory refs invalidated it,
504 use it the old way. */
505 if (memory_address_p (mode, oldx))
506 goto win2;
508 /* Perform machine-dependent transformations on X
509 in certain cases. This is not necessary since the code
510 below can handle all possible cases, but machine-dependent
511 transformations can make better code. */
512 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
514 /* PLUS and MULT can appear in special ways
515 as the result of attempts to make an address usable for indexing.
516 Usually they are dealt with by calling force_operand, below.
517 But a sum containing constant terms is special
518 if removing them makes the sum a valid address:
519 then we generate that address in a register
520 and index off of it. We do this because it often makes
521 shorter code, and because the addresses thus generated
522 in registers often become common subexpressions. */
523 if (GET_CODE (x) == PLUS)
525 rtx constant_term = const0_rtx;
526 rtx y = eliminate_constant_term (x, &constant_term);
527 if (constant_term == const0_rtx
528 || ! memory_address_p (mode, y))
529 x = force_operand (x, NULL_RTX);
530 else
532 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
533 if (! memory_address_p (mode, y))
534 x = force_operand (x, NULL_RTX);
535 else
536 x = y;
540 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
541 x = force_operand (x, NULL_RTX);
543 /* If we have a register that's an invalid address,
544 it must be a hard reg of the wrong class. Copy it to a pseudo. */
545 else if (GET_CODE (x) == REG)
546 x = copy_to_reg (x);
548 /* Last resort: copy the value to a register, since
549 the register is a valid address. */
550 else
551 x = force_reg (Pmode, x);
553 goto done;
555 win2:
556 x = oldx;
557 win:
558 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG
559 /* Don't copy an addr via a reg if it is one of our stack slots. */
560 && ! (GET_CODE (x) == PLUS
561 && (XEXP (x, 0) == virtual_stack_vars_rtx
562 || XEXP (x, 0) == virtual_incoming_args_rtx)))
564 if (general_operand (x, Pmode))
565 x = force_reg (Pmode, x);
566 else
567 x = force_operand (x, NULL_RTX);
571 done:
573 /* If we didn't change the address, we are done. Otherwise, mark
574 a reg as a pointer if we have REG or REG + CONST_INT. */
575 if (oldx == x)
576 return x;
577 else if (GET_CODE (x) == REG)
578 mark_reg_pointer (x, BITS_PER_UNIT);
579 else if (GET_CODE (x) == PLUS
580 && GET_CODE (XEXP (x, 0)) == REG
581 && GET_CODE (XEXP (x, 1)) == CONST_INT)
582 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
584 /* OLDX may have been the address on a temporary. Update the address
585 to indicate that X is now used. */
586 update_temp_slot_address (oldx, x);
588 return x;
591 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
594 memory_address_noforce (mode, x)
595 enum machine_mode mode;
596 rtx x;
598 int ambient_force_addr = flag_force_addr;
599 rtx val;
601 flag_force_addr = 0;
602 val = memory_address (mode, x);
603 flag_force_addr = ambient_force_addr;
604 return val;
607 /* Convert a mem ref into one with a valid memory address.
608 Pass through anything else unchanged. */
611 validize_mem (ref)
612 rtx ref;
614 if (GET_CODE (ref) != MEM)
615 return ref;
616 if (memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
617 return ref;
618 /* Don't alter REF itself, since that is probably a stack slot. */
619 return change_address (ref, GET_MODE (ref), XEXP (ref, 0));
622 /* Given REF, either a MEM or a REG, and T, either the type of X or
623 the expression corresponding to REF, set RTX_UNCHANGING_P if
624 appropriate. */
626 void
627 maybe_set_unchanging (ref, t)
628 rtx ref;
629 tree t;
631 /* We can set RTX_UNCHANGING_P from TREE_READONLY for decls whose
632 initialization is only executed once, or whose initializer always
633 has the same value. Currently we simplify this to PARM_DECLs in the
634 first case, and decls with TREE_CONSTANT initializers in the second. */
635 if ((TREE_READONLY (t) && DECL_P (t)
636 && (TREE_CODE (t) == PARM_DECL
637 || DECL_INITIAL (t) == NULL_TREE
638 || TREE_CONSTANT (DECL_INITIAL (t))))
639 || TREE_CODE_CLASS (TREE_CODE (t)) == 'c')
640 RTX_UNCHANGING_P (ref) = 1;
643 /* Given REF, a MEM, and T, either the type of X or the expression
644 corresponding to REF, set the memory attributes. OBJECTP is nonzero
645 if we are making a new object of this type. */
647 void
648 set_mem_attributes (ref, t, objectp)
649 rtx ref;
650 tree t;
651 int objectp;
653 tree type;
655 /* It can happen that type_for_mode was given a mode for which there
656 is no language-level type. In which case it returns NULL, which
657 we can see here. */
658 if (t == NULL_TREE)
659 return;
661 type = TYPE_P (t) ? t : TREE_TYPE (t);
663 /* Get the alias set from the expression or type (perhaps using a
664 front-end routine) and then copy bits from the type. */
666 /* It is incorrect to set RTX_UNCHANGING_P from TREE_READONLY (type)
667 here, because, in C and C++, the fact that a location is accessed
668 through a const expression does not mean that the value there can
669 never change. */
670 MEM_ALIAS_SET (ref) = get_alias_set (t);
671 MEM_VOLATILE_P (ref) = TYPE_VOLATILE (type);
672 MEM_IN_STRUCT_P (ref) = AGGREGATE_TYPE_P (type);
674 /* If we are making an object of this type, we know that it is a scalar if
675 the type is not an aggregate. */
676 if (objectp && ! AGGREGATE_TYPE_P (type))
677 MEM_SCALAR_P (ref) = 1;
679 /* If T is a type, this is all we can do. Otherwise, we may be able
680 to deduce some more information about the expression. */
681 if (TYPE_P (t))
682 return;
684 maybe_set_unchanging (ref, t);
685 if (TREE_THIS_VOLATILE (t))
686 MEM_VOLATILE_P (ref) = 1;
688 /* Now see if we can say more about whether it's an aggregate or
689 scalar. If we already know it's an aggregate, don't bother. */
690 if (MEM_IN_STRUCT_P (ref))
691 return;
693 /* Now remove any NOPs: they don't change what the underlying object is.
694 Likewise for SAVE_EXPR. */
695 while (TREE_CODE (t) == NOP_EXPR || TREE_CODE (t) == CONVERT_EXPR
696 || TREE_CODE (t) == NON_LVALUE_EXPR || TREE_CODE (t) == SAVE_EXPR)
697 t = TREE_OPERAND (t, 0);
699 /* Since we already know the type isn't an aggregate, if this is a decl,
700 it must be a scalar. Or if it is a reference into an aggregate,
701 this is part of an aggregate. Otherwise we don't know. */
702 if (DECL_P (t))
703 MEM_SCALAR_P (ref) = 1;
704 else if (TREE_CODE (t) == COMPONENT_REF || TREE_CODE (t) == ARRAY_REF
705 || TREE_CODE (t) == BIT_FIELD_REF)
706 MEM_IN_STRUCT_P (ref) = 1;
709 /* Return a modified copy of X with its memory address copied
710 into a temporary register to protect it from side effects.
711 If X is not a MEM, it is returned unchanged (and not copied).
712 Perhaps even if it is a MEM, if there is no need to change it. */
715 stabilize (x)
716 rtx x;
718 register rtx addr;
720 if (GET_CODE (x) != MEM)
721 return x;
723 addr = XEXP (x, 0);
724 if (rtx_unstable_p (addr))
726 rtx temp = force_reg (Pmode, copy_all_regs (addr));
727 rtx mem = gen_rtx_MEM (GET_MODE (x), temp);
729 MEM_COPY_ATTRIBUTES (mem, x);
730 return mem;
732 return x;
735 /* Copy the value or contents of X to a new temp reg and return that reg. */
738 copy_to_reg (x)
739 rtx x;
741 register rtx temp = gen_reg_rtx (GET_MODE (x));
743 /* If not an operand, must be an address with PLUS and MULT so
744 do the computation. */
745 if (! general_operand (x, VOIDmode))
746 x = force_operand (x, temp);
748 if (x != temp)
749 emit_move_insn (temp, x);
751 return temp;
754 /* Like copy_to_reg but always give the new register mode Pmode
755 in case X is a constant. */
758 copy_addr_to_reg (x)
759 rtx x;
761 return copy_to_mode_reg (Pmode, x);
764 /* Like copy_to_reg but always give the new register mode MODE
765 in case X is a constant. */
768 copy_to_mode_reg (mode, x)
769 enum machine_mode mode;
770 rtx x;
772 register rtx temp = gen_reg_rtx (mode);
774 /* If not an operand, must be an address with PLUS and MULT so
775 do the computation. */
776 if (! general_operand (x, VOIDmode))
777 x = force_operand (x, temp);
779 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
780 abort ();
781 if (x != temp)
782 emit_move_insn (temp, x);
783 return temp;
786 /* Load X into a register if it is not already one.
787 Use mode MODE for the register.
788 X should be valid for mode MODE, but it may be a constant which
789 is valid for all integer modes; that's why caller must specify MODE.
791 The caller must not alter the value in the register we return,
792 since we mark it as a "constant" register. */
795 force_reg (mode, x)
796 enum machine_mode mode;
797 rtx x;
799 register rtx temp, insn, set;
801 if (GET_CODE (x) == REG)
802 return x;
804 temp = gen_reg_rtx (mode);
806 if (! general_operand (x, mode))
807 x = force_operand (x, NULL_RTX);
809 insn = emit_move_insn (temp, x);
811 /* Let optimizers know that TEMP's value never changes
812 and that X can be substituted for it. Don't get confused
813 if INSN set something else (such as a SUBREG of TEMP). */
814 if (CONSTANT_P (x)
815 && (set = single_set (insn)) != 0
816 && SET_DEST (set) == temp)
818 rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
820 if (note)
821 XEXP (note, 0) = x;
822 else
823 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EQUAL, x, REG_NOTES (insn));
825 return temp;
828 /* If X is a memory ref, copy its contents to a new temp reg and return
829 that reg. Otherwise, return X. */
832 force_not_mem (x)
833 rtx x;
835 register rtx temp;
837 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode)
838 return x;
840 temp = gen_reg_rtx (GET_MODE (x));
841 emit_move_insn (temp, x);
842 return temp;
845 /* Copy X to TARGET (if it's nonzero and a reg)
846 or to a new temp reg and return that reg.
847 MODE is the mode to use for X in case it is a constant. */
850 copy_to_suggested_reg (x, target, mode)
851 rtx x, target;
852 enum machine_mode mode;
854 register rtx temp;
856 if (target && GET_CODE (target) == REG)
857 temp = target;
858 else
859 temp = gen_reg_rtx (mode);
861 emit_move_insn (temp, x);
862 return temp;
865 /* Return the mode to use to store a scalar of TYPE and MODE.
866 PUNSIGNEDP points to the signedness of the type and may be adjusted
867 to show what signedness to use on extension operations.
869 FOR_CALL is non-zero if this call is promoting args for a call. */
871 enum machine_mode
872 promote_mode (type, mode, punsignedp, for_call)
873 tree type;
874 enum machine_mode mode;
875 int *punsignedp;
876 int for_call ATTRIBUTE_UNUSED;
878 enum tree_code code = TREE_CODE (type);
879 int unsignedp = *punsignedp;
881 #ifdef PROMOTE_FOR_CALL_ONLY
882 if (! for_call)
883 return mode;
884 #endif
886 switch (code)
888 #ifdef PROMOTE_MODE
889 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
890 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
891 PROMOTE_MODE (mode, unsignedp, type);
892 break;
893 #endif
895 #ifdef POINTERS_EXTEND_UNSIGNED
896 case REFERENCE_TYPE:
897 case POINTER_TYPE:
898 mode = Pmode;
899 unsignedp = POINTERS_EXTEND_UNSIGNED;
900 break;
901 #endif
903 default:
904 break;
907 *punsignedp = unsignedp;
908 return mode;
911 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
912 This pops when ADJUST is positive. ADJUST need not be constant. */
914 void
915 adjust_stack (adjust)
916 rtx adjust;
918 rtx temp;
919 adjust = protect_from_queue (adjust, 0);
921 if (adjust == const0_rtx)
922 return;
924 /* We expect all variable sized adjustments to be multiple of
925 PREFERRED_STACK_BOUNDARY. */
926 if (GET_CODE (adjust) == CONST_INT)
927 stack_pointer_delta -= INTVAL (adjust);
929 temp = expand_binop (Pmode,
930 #ifdef STACK_GROWS_DOWNWARD
931 add_optab,
932 #else
933 sub_optab,
934 #endif
935 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
936 OPTAB_LIB_WIDEN);
938 if (temp != stack_pointer_rtx)
939 emit_move_insn (stack_pointer_rtx, temp);
942 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
943 This pushes when ADJUST is positive. ADJUST need not be constant. */
945 void
946 anti_adjust_stack (adjust)
947 rtx adjust;
949 rtx temp;
950 adjust = protect_from_queue (adjust, 0);
952 if (adjust == const0_rtx)
953 return;
955 /* We expect all variable sized adjustments to be multiple of
956 PREFERRED_STACK_BOUNDARY. */
957 if (GET_CODE (adjust) == CONST_INT)
958 stack_pointer_delta += INTVAL (adjust);
960 temp = expand_binop (Pmode,
961 #ifdef STACK_GROWS_DOWNWARD
962 sub_optab,
963 #else
964 add_optab,
965 #endif
966 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
967 OPTAB_LIB_WIDEN);
969 if (temp != stack_pointer_rtx)
970 emit_move_insn (stack_pointer_rtx, temp);
973 /* Round the size of a block to be pushed up to the boundary required
974 by this machine. SIZE is the desired size, which need not be constant. */
977 round_push (size)
978 rtx size;
980 #ifdef PREFERRED_STACK_BOUNDARY
981 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
982 if (align == 1)
983 return size;
984 if (GET_CODE (size) == CONST_INT)
986 int new = (INTVAL (size) + align - 1) / align * align;
987 if (INTVAL (size) != new)
988 size = GEN_INT (new);
990 else
992 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
993 but we know it can't. So add ourselves and then do
994 TRUNC_DIV_EXPR. */
995 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
996 NULL_RTX, 1, OPTAB_LIB_WIDEN);
997 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
998 NULL_RTX, 1);
999 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
1001 #endif /* PREFERRED_STACK_BOUNDARY */
1002 return size;
1005 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
1006 to a previously-created save area. If no save area has been allocated,
1007 this function will allocate one. If a save area is specified, it
1008 must be of the proper mode.
1010 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
1011 are emitted at the current position. */
1013 void
1014 emit_stack_save (save_level, psave, after)
1015 enum save_level save_level;
1016 rtx *psave;
1017 rtx after;
1019 rtx sa = *psave;
1020 /* The default is that we use a move insn and save in a Pmode object. */
1021 rtx (*fcn) PARAMS ((rtx, rtx)) = gen_move_insn;
1022 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
1024 /* See if this machine has anything special to do for this kind of save. */
1025 switch (save_level)
1027 #ifdef HAVE_save_stack_block
1028 case SAVE_BLOCK:
1029 if (HAVE_save_stack_block)
1030 fcn = gen_save_stack_block;
1031 break;
1032 #endif
1033 #ifdef HAVE_save_stack_function
1034 case SAVE_FUNCTION:
1035 if (HAVE_save_stack_function)
1036 fcn = gen_save_stack_function;
1037 break;
1038 #endif
1039 #ifdef HAVE_save_stack_nonlocal
1040 case SAVE_NONLOCAL:
1041 if (HAVE_save_stack_nonlocal)
1042 fcn = gen_save_stack_nonlocal;
1043 break;
1044 #endif
1045 default:
1046 break;
1049 /* If there is no save area and we have to allocate one, do so. Otherwise
1050 verify the save area is the proper mode. */
1052 if (sa == 0)
1054 if (mode != VOIDmode)
1056 if (save_level == SAVE_NONLOCAL)
1057 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
1058 else
1059 *psave = sa = gen_reg_rtx (mode);
1062 else
1064 if (mode == VOIDmode || GET_MODE (sa) != mode)
1065 abort ();
1068 if (after)
1070 rtx seq;
1072 start_sequence ();
1073 /* We must validize inside the sequence, to ensure that any instructions
1074 created by the validize call also get moved to the right place. */
1075 if (sa != 0)
1076 sa = validize_mem (sa);
1077 emit_insn (fcn (sa, stack_pointer_rtx));
1078 seq = gen_sequence ();
1079 end_sequence ();
1080 emit_insn_after (seq, after);
1082 else
1084 if (sa != 0)
1085 sa = validize_mem (sa);
1086 emit_insn (fcn (sa, stack_pointer_rtx));
1090 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1091 area made by emit_stack_save. If it is zero, we have nothing to do.
1093 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1094 current position. */
1096 void
1097 emit_stack_restore (save_level, sa, after)
1098 enum save_level save_level;
1099 rtx after;
1100 rtx sa;
1102 /* The default is that we use a move insn. */
1103 rtx (*fcn) PARAMS ((rtx, rtx)) = gen_move_insn;
1105 /* See if this machine has anything special to do for this kind of save. */
1106 switch (save_level)
1108 #ifdef HAVE_restore_stack_block
1109 case SAVE_BLOCK:
1110 if (HAVE_restore_stack_block)
1111 fcn = gen_restore_stack_block;
1112 break;
1113 #endif
1114 #ifdef HAVE_restore_stack_function
1115 case SAVE_FUNCTION:
1116 if (HAVE_restore_stack_function)
1117 fcn = gen_restore_stack_function;
1118 break;
1119 #endif
1120 #ifdef HAVE_restore_stack_nonlocal
1121 case SAVE_NONLOCAL:
1122 if (HAVE_restore_stack_nonlocal)
1123 fcn = gen_restore_stack_nonlocal;
1124 break;
1125 #endif
1126 default:
1127 break;
1130 if (sa != 0)
1131 sa = validize_mem (sa);
1133 if (after)
1135 rtx seq;
1137 start_sequence ();
1138 emit_insn (fcn (stack_pointer_rtx, sa));
1139 seq = gen_sequence ();
1140 end_sequence ();
1141 emit_insn_after (seq, after);
1143 else
1144 emit_insn (fcn (stack_pointer_rtx, sa));
1147 #ifdef SETJMP_VIA_SAVE_AREA
1148 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1149 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1150 platforms, the dynamic stack space used can corrupt the original
1151 frame, thus causing a crash if a longjmp unwinds to it. */
1153 void
1154 optimize_save_area_alloca (insns)
1155 rtx insns;
1157 rtx insn;
1159 for (insn = insns; insn; insn = NEXT_INSN(insn))
1161 rtx note;
1163 if (GET_CODE (insn) != INSN)
1164 continue;
1166 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1168 if (REG_NOTE_KIND (note) != REG_SAVE_AREA)
1169 continue;
1171 if (!current_function_calls_setjmp)
1173 rtx pat = PATTERN (insn);
1175 /* If we do not see the note in a pattern matching
1176 these precise characteristics, we did something
1177 entirely wrong in allocate_dynamic_stack_space.
1179 Note, one way this could happen is if SETJMP_VIA_SAVE_AREA
1180 was defined on a machine where stacks grow towards higher
1181 addresses.
1183 Right now only supported port with stack that grow upward
1184 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1185 if (GET_CODE (pat) != SET
1186 || SET_DEST (pat) != stack_pointer_rtx
1187 || GET_CODE (SET_SRC (pat)) != MINUS
1188 || XEXP (SET_SRC (pat), 0) != stack_pointer_rtx)
1189 abort ();
1191 /* This will now be transformed into a (set REG REG)
1192 so we can just blow away all the other notes. */
1193 XEXP (SET_SRC (pat), 1) = XEXP (note, 0);
1194 REG_NOTES (insn) = NULL_RTX;
1196 else
1198 /* setjmp was called, we must remove the REG_SAVE_AREA
1199 note so that later passes do not get confused by its
1200 presence. */
1201 if (note == REG_NOTES (insn))
1203 REG_NOTES (insn) = XEXP (note, 1);
1205 else
1207 rtx srch;
1209 for (srch = REG_NOTES (insn); srch; srch = XEXP (srch, 1))
1210 if (XEXP (srch, 1) == note)
1211 break;
1213 if (srch == NULL_RTX)
1214 abort();
1216 XEXP (srch, 1) = XEXP (note, 1);
1219 /* Once we've seen the note of interest, we need not look at
1220 the rest of them. */
1221 break;
1225 #endif /* SETJMP_VIA_SAVE_AREA */
1227 /* Return an rtx representing the address of an area of memory dynamically
1228 pushed on the stack. This region of memory is always aligned to
1229 a multiple of BIGGEST_ALIGNMENT.
1231 Any required stack pointer alignment is preserved.
1233 SIZE is an rtx representing the size of the area.
1234 TARGET is a place in which the address can be placed.
1236 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1239 allocate_dynamic_stack_space (size, target, known_align)
1240 rtx size;
1241 rtx target;
1242 int known_align;
1244 #ifdef SETJMP_VIA_SAVE_AREA
1245 rtx setjmpless_size = NULL_RTX;
1246 #endif
1248 /* If we're asking for zero bytes, it doesn't matter what we point
1249 to since we can't dereference it. But return a reasonable
1250 address anyway. */
1251 if (size == const0_rtx)
1252 return virtual_stack_dynamic_rtx;
1254 /* Otherwise, show we're calling alloca or equivalent. */
1255 current_function_calls_alloca = 1;
1257 /* Ensure the size is in the proper mode. */
1258 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1259 size = convert_to_mode (Pmode, size, 1);
1261 /* We can't attempt to minimize alignment necessary, because we don't
1262 know the final value of preferred_stack_boundary yet while executing
1263 this code. */
1264 #ifdef PREFERRED_STACK_BOUNDARY
1265 cfun->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1266 #endif
1268 /* We will need to ensure that the address we return is aligned to
1269 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1270 always know its final value at this point in the compilation (it
1271 might depend on the size of the outgoing parameter lists, for
1272 example), so we must align the value to be returned in that case.
1273 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if
1274 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1275 We must also do an alignment operation on the returned value if
1276 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1278 If we have to align, we must leave space in SIZE for the hole
1279 that might result from the alignment operation. */
1281 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) || ! defined (PREFERRED_STACK_BOUNDARY)
1282 #define MUST_ALIGN 1
1283 #else
1284 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1285 #endif
1287 if (MUST_ALIGN)
1288 size
1289 = force_operand (plus_constant (size,
1290 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1291 NULL_RTX);
1293 #ifdef SETJMP_VIA_SAVE_AREA
1294 /* If setjmp restores regs from a save area in the stack frame,
1295 avoid clobbering the reg save area. Note that the offset of
1296 virtual_incoming_args_rtx includes the preallocated stack args space.
1297 It would be no problem to clobber that, but it's on the wrong side
1298 of the old save area. */
1300 rtx dynamic_offset
1301 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1302 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1304 if (!current_function_calls_setjmp)
1306 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1308 /* See optimize_save_area_alloca to understand what is being
1309 set up here. */
1311 #if !defined(PREFERRED_STACK_BOUNDARY) || !defined(MUST_ALIGN) || (PREFERRED_STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1312 /* If anyone creates a target with these characteristics, let them
1313 know that our optimization cannot work correctly in such a case. */
1314 abort ();
1315 #endif
1317 if (GET_CODE (size) == CONST_INT)
1319 HOST_WIDE_INT new = INTVAL (size) / align * align;
1321 if (INTVAL (size) != new)
1322 setjmpless_size = GEN_INT (new);
1323 else
1324 setjmpless_size = size;
1326 else
1328 /* Since we know overflow is not possible, we avoid using
1329 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1330 setjmpless_size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1331 GEN_INT (align), NULL_RTX, 1);
1332 setjmpless_size = expand_mult (Pmode, setjmpless_size,
1333 GEN_INT (align), NULL_RTX, 1);
1335 /* Our optimization works based upon being able to perform a simple
1336 transformation of this RTL into a (set REG REG) so make sure things
1337 did in fact end up in a REG. */
1338 if (!register_operand (setjmpless_size, Pmode))
1339 setjmpless_size = force_reg (Pmode, setjmpless_size);
1342 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1343 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1345 #endif /* SETJMP_VIA_SAVE_AREA */
1347 /* Round the size to a multiple of the required stack alignment.
1348 Since the stack if presumed to be rounded before this allocation,
1349 this will maintain the required alignment.
1351 If the stack grows downward, we could save an insn by subtracting
1352 SIZE from the stack pointer and then aligning the stack pointer.
1353 The problem with this is that the stack pointer may be unaligned
1354 between the execution of the subtraction and alignment insns and
1355 some machines do not allow this. Even on those that do, some
1356 signal handlers malfunction if a signal should occur between those
1357 insns. Since this is an extremely rare event, we have no reliable
1358 way of knowing which systems have this problem. So we avoid even
1359 momentarily mis-aligning the stack. */
1361 #ifdef PREFERRED_STACK_BOUNDARY
1362 /* If we added a variable amount to SIZE,
1363 we can no longer assume it is aligned. */
1364 #if !defined (SETJMP_VIA_SAVE_AREA)
1365 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1366 #endif
1367 size = round_push (size);
1368 #endif
1370 do_pending_stack_adjust ();
1372 /* We ought to be called always on the toplevel and stack ought to be aligned
1373 propertly. */
1374 #ifdef PREFERRED_STACK_BOUNDARY
1375 if (stack_pointer_delta % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT))
1376 abort ();
1377 #endif
1379 /* If needed, check that we have the required amount of stack. Take into
1380 account what has already been checked. */
1381 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1382 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1384 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1385 if (target == 0 || GET_CODE (target) != REG
1386 || REGNO (target) < FIRST_PSEUDO_REGISTER
1387 || GET_MODE (target) != Pmode)
1388 target = gen_reg_rtx (Pmode);
1390 mark_reg_pointer (target, known_align);
1392 /* Perform the required allocation from the stack. Some systems do
1393 this differently than simply incrementing/decrementing from the
1394 stack pointer, such as acquiring the space by calling malloc(). */
1395 #ifdef HAVE_allocate_stack
1396 if (HAVE_allocate_stack)
1398 enum machine_mode mode = STACK_SIZE_MODE;
1399 insn_operand_predicate_fn pred;
1401 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[0].predicate;
1402 if (pred && ! ((*pred) (target, Pmode)))
1403 #ifdef POINTERS_EXTEND_UNSIGNED
1404 target = convert_memory_address (Pmode, target);
1405 #else
1406 target = copy_to_mode_reg (Pmode, target);
1407 #endif
1409 if (mode == VOIDmode)
1410 mode = Pmode;
1412 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1413 if (pred && ! ((*pred) (size, mode)))
1414 size = copy_to_mode_reg (mode, size);
1416 emit_insn (gen_allocate_stack (target, size));
1418 else
1419 #endif
1421 #ifndef STACK_GROWS_DOWNWARD
1422 emit_move_insn (target, virtual_stack_dynamic_rtx);
1423 #endif
1425 /* Check stack bounds if necessary. */
1426 if (current_function_limit_stack)
1428 rtx available;
1429 rtx space_available = gen_label_rtx ();
1430 #ifdef STACK_GROWS_DOWNWARD
1431 available = expand_binop (Pmode, sub_optab,
1432 stack_pointer_rtx, stack_limit_rtx,
1433 NULL_RTX, 1, OPTAB_WIDEN);
1434 #else
1435 available = expand_binop (Pmode, sub_optab,
1436 stack_limit_rtx, stack_pointer_rtx,
1437 NULL_RTX, 1, OPTAB_WIDEN);
1438 #endif
1439 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1440 0, space_available);
1441 #ifdef HAVE_trap
1442 if (HAVE_trap)
1443 emit_insn (gen_trap ());
1444 else
1445 #endif
1446 error ("stack limits not supported on this target");
1447 emit_barrier ();
1448 emit_label (space_available);
1451 anti_adjust_stack (size);
1452 #ifdef SETJMP_VIA_SAVE_AREA
1453 if (setjmpless_size != NULL_RTX)
1455 rtx note_target = get_last_insn ();
1457 REG_NOTES (note_target)
1458 = gen_rtx_EXPR_LIST (REG_SAVE_AREA, setjmpless_size,
1459 REG_NOTES (note_target));
1461 #endif /* SETJMP_VIA_SAVE_AREA */
1463 #ifdef STACK_GROWS_DOWNWARD
1464 emit_move_insn (target, virtual_stack_dynamic_rtx);
1465 #endif
1468 if (MUST_ALIGN)
1470 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1471 but we know it can't. So add ourselves and then do
1472 TRUNC_DIV_EXPR. */
1473 target = expand_binop (Pmode, add_optab, target,
1474 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1475 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1476 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1477 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1478 NULL_RTX, 1);
1479 target = expand_mult (Pmode, target,
1480 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1481 NULL_RTX, 1);
1484 /* Some systems require a particular insn to refer to the stack
1485 to make the pages exist. */
1486 #ifdef HAVE_probe
1487 if (HAVE_probe)
1488 emit_insn (gen_probe ());
1489 #endif
1491 /* Record the new stack level for nonlocal gotos. */
1492 if (nonlocal_goto_handler_slots != 0)
1493 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
1495 return target;
1498 /* A front end may want to override GCC's stack checking by providing a
1499 run-time routine to call to check the stack, so provide a mechanism for
1500 calling that routine. */
1502 static rtx stack_check_libfunc;
1504 void
1505 set_stack_check_libfunc (libfunc)
1506 rtx libfunc;
1508 stack_check_libfunc = libfunc;
1511 /* Emit one stack probe at ADDRESS, an address within the stack. */
1513 static void
1514 emit_stack_probe (address)
1515 rtx address;
1517 rtx memref = gen_rtx_MEM (word_mode, address);
1519 MEM_VOLATILE_P (memref) = 1;
1521 if (STACK_CHECK_PROBE_LOAD)
1522 emit_move_insn (gen_reg_rtx (word_mode), memref);
1523 else
1524 emit_move_insn (memref, const0_rtx);
1527 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1528 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1529 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1530 subtract from the stack. If SIZE is constant, this is done
1531 with a fixed number of probes. Otherwise, we must make a loop. */
1533 #ifdef STACK_GROWS_DOWNWARD
1534 #define STACK_GROW_OP MINUS
1535 #else
1536 #define STACK_GROW_OP PLUS
1537 #endif
1539 void
1540 probe_stack_range (first, size)
1541 HOST_WIDE_INT first;
1542 rtx size;
1544 /* First see if the front end has set up a function for us to call to
1545 check the stack. */
1546 if (stack_check_libfunc != 0)
1548 rtx addr = memory_address (QImode,
1549 gen_rtx (STACK_GROW_OP, Pmode,
1550 stack_pointer_rtx,
1551 plus_constant (size, first)));
1553 #ifdef POINTERS_EXTEND_UNSIGNED
1554 if (GET_MODE (addr) != ptr_mode)
1555 addr = convert_memory_address (ptr_mode, addr);
1556 #endif
1558 emit_library_call (stack_check_libfunc, 0, VOIDmode, 1, addr,
1559 ptr_mode);
1562 /* Next see if we have an insn to check the stack. Use it if so. */
1563 #ifdef HAVE_check_stack
1564 else if (HAVE_check_stack)
1566 insn_operand_predicate_fn pred;
1567 rtx last_addr
1568 = force_operand (gen_rtx_STACK_GROW_OP (Pmode,
1569 stack_pointer_rtx,
1570 plus_constant (size, first)),
1571 NULL_RTX);
1573 pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1574 if (pred && ! ((*pred) (last_addr, Pmode)))
1575 last_addr = copy_to_mode_reg (Pmode, last_addr);
1577 emit_insn (gen_check_stack (last_addr));
1579 #endif
1581 /* If we have to generate explicit probes, see if we have a constant
1582 small number of them to generate. If so, that's the easy case. */
1583 else if (GET_CODE (size) == CONST_INT
1584 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1586 HOST_WIDE_INT offset;
1588 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1589 for values of N from 1 until it exceeds LAST. If only one
1590 probe is needed, this will not generate any code. Then probe
1591 at LAST. */
1592 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1593 offset < INTVAL (size);
1594 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1595 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1596 stack_pointer_rtx,
1597 GEN_INT (offset)));
1599 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1600 stack_pointer_rtx,
1601 plus_constant (size, first)));
1604 /* In the variable case, do the same as above, but in a loop. We emit loop
1605 notes so that loop optimization can be done. */
1606 else
1608 rtx test_addr
1609 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1610 stack_pointer_rtx,
1611 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1612 NULL_RTX);
1613 rtx last_addr
1614 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1615 stack_pointer_rtx,
1616 plus_constant (size, first)),
1617 NULL_RTX);
1618 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1619 rtx loop_lab = gen_label_rtx ();
1620 rtx test_lab = gen_label_rtx ();
1621 rtx end_lab = gen_label_rtx ();
1622 rtx temp;
1624 if (GET_CODE (test_addr) != REG
1625 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1626 test_addr = force_reg (Pmode, test_addr);
1628 emit_note (NULL, NOTE_INSN_LOOP_BEG);
1629 emit_jump (test_lab);
1631 emit_label (loop_lab);
1632 emit_stack_probe (test_addr);
1634 emit_note (NULL, NOTE_INSN_LOOP_CONT);
1636 #ifdef STACK_GROWS_DOWNWARD
1637 #define CMP_OPCODE GTU
1638 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1639 1, OPTAB_WIDEN);
1640 #else
1641 #define CMP_OPCODE LTU
1642 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1643 1, OPTAB_WIDEN);
1644 #endif
1646 if (temp != test_addr)
1647 abort ();
1649 emit_label (test_lab);
1650 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1651 NULL_RTX, Pmode, 1, 0, loop_lab);
1652 emit_jump (end_lab);
1653 emit_note (NULL, NOTE_INSN_LOOP_END);
1654 emit_label (end_lab);
1656 emit_stack_probe (last_addr);
1660 /* Return an rtx representing the register or memory location
1661 in which a scalar value of data type VALTYPE
1662 was returned by a function call to function FUNC.
1663 FUNC is a FUNCTION_DECL node if the precise function is known,
1664 otherwise 0.
1665 OUTGOING is 1 if on a machine with register windows this function
1666 should return the register in which the function will put its result
1667 and 0 otherwise. */
1670 hard_function_value (valtype, func, outgoing)
1671 tree valtype;
1672 tree func ATTRIBUTE_UNUSED;
1673 int outgoing ATTRIBUTE_UNUSED;
1675 rtx val;
1677 #ifdef FUNCTION_OUTGOING_VALUE
1678 if (outgoing)
1679 val = FUNCTION_OUTGOING_VALUE (valtype, func);
1680 else
1681 #endif
1682 val = FUNCTION_VALUE (valtype, func);
1684 if (GET_CODE (val) == REG
1685 && GET_MODE (val) == BLKmode)
1687 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1688 enum machine_mode tmpmode;
1690 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1691 tmpmode != VOIDmode;
1692 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1694 /* Have we found a large enough mode? */
1695 if (GET_MODE_SIZE (tmpmode) >= bytes)
1696 break;
1699 /* No suitable mode found. */
1700 if (tmpmode == VOIDmode)
1701 abort ();
1703 PUT_MODE (val, tmpmode);
1705 return val;
1708 /* Return an rtx representing the register or memory location
1709 in which a scalar value of mode MODE was returned by a library call. */
1712 hard_libcall_value (mode)
1713 enum machine_mode mode;
1715 return LIBCALL_VALUE (mode);
1718 /* Look up the tree code for a given rtx code
1719 to provide the arithmetic operation for REAL_ARITHMETIC.
1720 The function returns an int because the caller may not know
1721 what `enum tree_code' means. */
1724 rtx_to_tree_code (code)
1725 enum rtx_code code;
1727 enum tree_code tcode;
1729 switch (code)
1731 case PLUS:
1732 tcode = PLUS_EXPR;
1733 break;
1734 case MINUS:
1735 tcode = MINUS_EXPR;
1736 break;
1737 case MULT:
1738 tcode = MULT_EXPR;
1739 break;
1740 case DIV:
1741 tcode = RDIV_EXPR;
1742 break;
1743 case SMIN:
1744 tcode = MIN_EXPR;
1745 break;
1746 case SMAX:
1747 tcode = MAX_EXPR;
1748 break;
1749 default:
1750 tcode = LAST_AND_UNUSED_TREE_CODE;
1751 break;
1753 return ((int) tcode);