1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987, 91, 94, 95, 96, 1997 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
27 #include "hard-reg-set.h"
28 #include "insn-config.h"
30 #include "insn-flags.h"
31 #include "insn-codes.h"
33 static rtx break_out_memory_refs
PROTO((rtx
));
34 static void emit_stack_probe
PROTO((rtx
));
35 /* Return an rtx for the sum of X and the integer C.
37 This function should be used via the `plus_constant' macro. */
40 plus_constant_wide (x
, c
)
42 register HOST_WIDE_INT c
;
44 register RTX_CODE code
;
45 register enum machine_mode mode
;
59 return GEN_INT (INTVAL (x
) + c
);
63 HOST_WIDE_INT l1
= CONST_DOUBLE_LOW (x
);
64 HOST_WIDE_INT h1
= CONST_DOUBLE_HIGH (x
);
66 HOST_WIDE_INT h2
= c
< 0 ? ~0 : 0;
69 add_double (l1
, h1
, l2
, h2
, &lv
, &hv
);
71 return immed_double_const (lv
, hv
, VOIDmode
);
75 /* If this is a reference to the constant pool, try replacing it with
76 a reference to a new constant. If the resulting address isn't
77 valid, don't return it because we have no way to validize it. */
78 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
79 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
82 = force_const_mem (GET_MODE (x
),
83 plus_constant (get_pool_constant (XEXP (x
, 0)),
85 if (memory_address_p (GET_MODE (tem
), XEXP (tem
, 0)))
91 /* If adding to something entirely constant, set a flag
92 so that we can add a CONST around the result. */
103 /* The interesting case is adding the integer to a sum.
104 Look for constant term in the sum and combine
105 with C. For an integer constant term, we make a combined
106 integer. For a constant term that is not an explicit integer,
107 we cannot really combine, but group them together anyway.
109 Use a recursive call in case the remaining operand is something
110 that we handle specially, such as a SYMBOL_REF. */
112 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
)
113 return plus_constant (XEXP (x
, 0), c
+ INTVAL (XEXP (x
, 1)));
114 else if (CONSTANT_P (XEXP (x
, 0)))
115 return gen_rtx (PLUS
, mode
,
116 plus_constant (XEXP (x
, 0), c
),
118 else if (CONSTANT_P (XEXP (x
, 1)))
119 return gen_rtx (PLUS
, mode
,
121 plus_constant (XEXP (x
, 1), c
));
125 x
= gen_rtx (PLUS
, mode
, x
, GEN_INT (c
));
127 if (GET_CODE (x
) == SYMBOL_REF
|| GET_CODE (x
) == LABEL_REF
)
129 else if (all_constant
)
130 return gen_rtx (CONST
, mode
, x
);
135 /* This is the same as `plus_constant', except that it handles LO_SUM.
137 This function should be used via the `plus_constant_for_output' macro. */
140 plus_constant_for_output_wide (x
, c
)
142 register HOST_WIDE_INT c
;
144 register RTX_CODE code
= GET_CODE (x
);
145 register enum machine_mode mode
= GET_MODE (x
);
146 int all_constant
= 0;
148 if (GET_CODE (x
) == LO_SUM
)
149 return gen_rtx (LO_SUM
, mode
, XEXP (x
, 0),
150 plus_constant_for_output (XEXP (x
, 1), c
));
153 return plus_constant (x
, c
);
156 /* If X is a sum, return a new sum like X but lacking any constant terms.
157 Add all the removed constant terms into *CONSTPTR.
158 X itself is not altered. The result != X if and only if
159 it is not isomorphic to X. */
162 eliminate_constant_term (x
, constptr
)
169 if (GET_CODE (x
) != PLUS
)
172 /* First handle constants appearing at this level explicitly. */
173 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
174 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
), *constptr
,
176 && GET_CODE (tem
) == CONST_INT
)
179 return eliminate_constant_term (XEXP (x
, 0), constptr
);
183 x0
= eliminate_constant_term (XEXP (x
, 0), &tem
);
184 x1
= eliminate_constant_term (XEXP (x
, 1), &tem
);
185 if ((x1
!= XEXP (x
, 1) || x0
!= XEXP (x
, 0))
186 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
),
188 && GET_CODE (tem
) == CONST_INT
)
191 return gen_rtx (PLUS
, GET_MODE (x
), x0
, x1
);
197 /* Returns the insn that next references REG after INSN, or 0
198 if REG is clobbered before next referenced or we cannot find
199 an insn that references REG in a straight-line piece of code. */
202 find_next_ref (reg
, insn
)
208 for (insn
= NEXT_INSN (insn
); insn
; insn
= next
)
210 next
= NEXT_INSN (insn
);
211 if (GET_CODE (insn
) == NOTE
)
213 if (GET_CODE (insn
) == CODE_LABEL
214 || GET_CODE (insn
) == BARRIER
)
216 if (GET_CODE (insn
) == INSN
217 || GET_CODE (insn
) == JUMP_INSN
218 || GET_CODE (insn
) == CALL_INSN
)
220 if (reg_set_p (reg
, insn
))
222 if (reg_mentioned_p (reg
, PATTERN (insn
)))
224 if (GET_CODE (insn
) == JUMP_INSN
)
226 if (simplejump_p (insn
))
227 next
= JUMP_LABEL (insn
);
231 if (GET_CODE (insn
) == CALL_INSN
232 && REGNO (reg
) < FIRST_PSEUDO_REGISTER
233 && call_used_regs
[REGNO (reg
)])
242 /* Return an rtx for the size in bytes of the value of EXP. */
248 tree size
= size_in_bytes (TREE_TYPE (exp
));
250 if (TREE_CODE (size
) != INTEGER_CST
251 && contains_placeholder_p (size
))
252 size
= build (WITH_RECORD_EXPR
, sizetype
, size
, exp
);
254 return expand_expr (size
, NULL_RTX
, TYPE_MODE (sizetype
),
255 EXPAND_MEMORY_USE_BAD
);
258 /* Return a copy of X in which all memory references
259 and all constants that involve symbol refs
260 have been replaced with new temporary registers.
261 Also emit code to load the memory locations and constants
262 into those registers.
264 If X contains no such constants or memory references,
265 X itself (not a copy) is returned.
267 If a constant is found in the address that is not a legitimate constant
268 in an insn, it is left alone in the hope that it might be valid in the
271 X may contain no arithmetic except addition, subtraction and multiplication.
272 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
275 break_out_memory_refs (x
)
278 if (GET_CODE (x
) == MEM
279 || (CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
)
280 && GET_MODE (x
) != VOIDmode
))
281 x
= force_reg (GET_MODE (x
), x
);
282 else if (GET_CODE (x
) == PLUS
|| GET_CODE (x
) == MINUS
283 || GET_CODE (x
) == MULT
)
285 register rtx op0
= break_out_memory_refs (XEXP (x
, 0));
286 register rtx op1
= break_out_memory_refs (XEXP (x
, 1));
288 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
289 x
= gen_rtx (GET_CODE (x
), Pmode
, op0
, op1
);
295 #ifdef POINTERS_EXTEND_UNSIGNED
297 /* Given X, a memory address in ptr_mode, convert it to an address
298 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
299 the fact that pointers are not allowed to overflow by commuting arithmetic
300 operations over conversions so that address arithmetic insns can be
304 convert_memory_address (to_mode
, x
)
305 enum machine_mode to_mode
;
308 enum machine_mode from_mode
= to_mode
== ptr_mode
? Pmode
: ptr_mode
;
311 /* Here we handle some special cases. If none of them apply, fall through
312 to the default case. */
313 switch (GET_CODE (x
))
320 return gen_rtx (LABEL_REF
, to_mode
, XEXP (x
, 0));
323 temp
= gen_rtx (SYMBOL_REF
, to_mode
, XSTR (x
, 0));
324 SYMBOL_REF_FLAG (temp
) = SYMBOL_REF_FLAG (x
);
325 CONSTANT_POOL_ADDRESS_P (temp
) = CONSTANT_POOL_ADDRESS_P (x
);
329 return gen_rtx (CONST
, to_mode
,
330 convert_memory_address (to_mode
, XEXP (x
, 0)));
334 /* For addition the second operand is a small constant, we can safely
335 permute the converstion and addition operation. We can always safely
336 permute them if we are making the address narrower. In addition,
337 always permute the operations if this is a constant. */
338 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
)
339 || (GET_CODE (x
) == PLUS
&& GET_CODE (XEXP (x
, 1)) == CONST_INT
340 && (INTVAL (XEXP (x
, 1)) + 20000 < 40000
341 || CONSTANT_P (XEXP (x
, 0)))))
342 return gen_rtx (GET_CODE (x
), to_mode
,
343 convert_memory_address (to_mode
, XEXP (x
, 0)),
344 convert_memory_address (to_mode
, XEXP (x
, 1)));
347 return convert_modes (to_mode
, from_mode
,
348 x
, POINTERS_EXTEND_UNSIGNED
);
352 /* Given a memory address or facsimile X, construct a new address,
353 currently equivalent, that is stable: future stores won't change it.
355 X must be composed of constants, register and memory references
356 combined with addition, subtraction and multiplication:
357 in other words, just what you can get from expand_expr if sum_ok is 1.
359 Works by making copies of all regs and memory locations used
360 by X and combining them the same way X does.
361 You could also stabilize the reference to this address
362 by copying the address to a register with copy_to_reg;
363 but then you wouldn't get indexed addressing in the reference. */
369 if (GET_CODE (x
) == REG
)
371 if (REGNO (x
) != FRAME_POINTER_REGNUM
372 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
373 && REGNO (x
) != HARD_FRAME_POINTER_REGNUM
378 else if (GET_CODE (x
) == MEM
)
380 else if (GET_CODE (x
) == PLUS
|| GET_CODE (x
) == MINUS
381 || GET_CODE (x
) == MULT
)
383 register rtx op0
= copy_all_regs (XEXP (x
, 0));
384 register rtx op1
= copy_all_regs (XEXP (x
, 1));
385 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
386 x
= gen_rtx (GET_CODE (x
), Pmode
, op0
, op1
);
391 /* Return something equivalent to X but valid as a memory address
392 for something of mode MODE. When X is not itself valid, this
393 works by copying X or subexpressions of it into registers. */
396 memory_address (mode
, x
)
397 enum machine_mode mode
;
400 register rtx oldx
= x
;
402 #ifdef POINTERS_EXTEND_UNSIGNED
403 if (GET_MODE (x
) == ptr_mode
)
404 x
= convert_memory_address (Pmode
, x
);
407 /* By passing constant addresses thru registers
408 we get a chance to cse them. */
409 if (! cse_not_expected
&& CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
))
410 x
= force_reg (Pmode
, x
);
412 /* Accept a QUEUED that refers to a REG
413 even though that isn't a valid address.
414 On attempting to put this in an insn we will call protect_from_queue
415 which will turn it into a REG, which is valid. */
416 else if (GET_CODE (x
) == QUEUED
417 && GET_CODE (QUEUED_VAR (x
)) == REG
)
420 /* We get better cse by rejecting indirect addressing at this stage.
421 Let the combiner create indirect addresses where appropriate.
422 For now, generate the code so that the subexpressions useful to share
423 are visible. But not if cse won't be done! */
426 if (! cse_not_expected
&& GET_CODE (x
) != REG
)
427 x
= break_out_memory_refs (x
);
429 /* At this point, any valid address is accepted. */
430 GO_IF_LEGITIMATE_ADDRESS (mode
, x
, win
);
432 /* If it was valid before but breaking out memory refs invalidated it,
433 use it the old way. */
434 if (memory_address_p (mode
, oldx
))
437 /* Perform machine-dependent transformations on X
438 in certain cases. This is not necessary since the code
439 below can handle all possible cases, but machine-dependent
440 transformations can make better code. */
441 LEGITIMIZE_ADDRESS (x
, oldx
, mode
, win
);
443 /* PLUS and MULT can appear in special ways
444 as the result of attempts to make an address usable for indexing.
445 Usually they are dealt with by calling force_operand, below.
446 But a sum containing constant terms is special
447 if removing them makes the sum a valid address:
448 then we generate that address in a register
449 and index off of it. We do this because it often makes
450 shorter code, and because the addresses thus generated
451 in registers often become common subexpressions. */
452 if (GET_CODE (x
) == PLUS
)
454 rtx constant_term
= const0_rtx
;
455 rtx y
= eliminate_constant_term (x
, &constant_term
);
456 if (constant_term
== const0_rtx
457 || ! memory_address_p (mode
, y
))
458 x
= force_operand (x
, NULL_RTX
);
461 y
= gen_rtx (PLUS
, GET_MODE (x
), copy_to_reg (y
), constant_term
);
462 if (! memory_address_p (mode
, y
))
463 x
= force_operand (x
, NULL_RTX
);
469 else if (GET_CODE (x
) == MULT
|| GET_CODE (x
) == MINUS
)
470 x
= force_operand (x
, NULL_RTX
);
472 /* If we have a register that's an invalid address,
473 it must be a hard reg of the wrong class. Copy it to a pseudo. */
474 else if (GET_CODE (x
) == REG
)
477 /* Last resort: copy the value to a register, since
478 the register is a valid address. */
480 x
= force_reg (Pmode
, x
);
487 if (flag_force_addr
&& ! cse_not_expected
&& GET_CODE (x
) != REG
488 /* Don't copy an addr via a reg if it is one of our stack slots. */
489 && ! (GET_CODE (x
) == PLUS
490 && (XEXP (x
, 0) == virtual_stack_vars_rtx
491 || XEXP (x
, 0) == virtual_incoming_args_rtx
)))
493 if (general_operand (x
, Pmode
))
494 x
= force_reg (Pmode
, x
);
496 x
= force_operand (x
, NULL_RTX
);
502 /* If we didn't change the address, we are done. Otherwise, mark
503 a reg as a pointer if we have REG or REG + CONST_INT. */
506 else if (GET_CODE (x
) == REG
)
507 mark_reg_pointer (x
, 1);
508 else if (GET_CODE (x
) == PLUS
509 && GET_CODE (XEXP (x
, 0)) == REG
510 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
511 mark_reg_pointer (XEXP (x
, 0), 1);
513 /* OLDX may have been the address on a temporary. Update the address
514 to indicate that X is now used. */
515 update_temp_slot_address (oldx
, x
);
520 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
523 memory_address_noforce (mode
, x
)
524 enum machine_mode mode
;
527 int ambient_force_addr
= flag_force_addr
;
531 val
= memory_address (mode
, x
);
532 flag_force_addr
= ambient_force_addr
;
536 /* Convert a mem ref into one with a valid memory address.
537 Pass through anything else unchanged. */
543 if (GET_CODE (ref
) != MEM
)
545 if (memory_address_p (GET_MODE (ref
), XEXP (ref
, 0)))
547 /* Don't alter REF itself, since that is probably a stack slot. */
548 return change_address (ref
, GET_MODE (ref
), XEXP (ref
, 0));
551 /* Return a modified copy of X with its memory address copied
552 into a temporary register to protect it from side effects.
553 If X is not a MEM, it is returned unchanged (and not copied).
554 Perhaps even if it is a MEM, if there is no need to change it. */
561 if (GET_CODE (x
) != MEM
)
564 if (rtx_unstable_p (addr
))
566 rtx temp
= copy_all_regs (addr
);
568 if (GET_CODE (temp
) != REG
)
569 temp
= copy_to_reg (temp
);
570 mem
= gen_rtx (MEM
, GET_MODE (x
), temp
);
572 /* Mark returned memref with in_struct if it's in an array or
573 structure. Copy const and volatile from original memref. */
575 MEM_IN_STRUCT_P (mem
) = MEM_IN_STRUCT_P (x
) || GET_CODE (addr
) == PLUS
;
576 RTX_UNCHANGING_P (mem
) = RTX_UNCHANGING_P (x
);
577 MEM_VOLATILE_P (mem
) = MEM_VOLATILE_P (x
);
583 /* Copy the value or contents of X to a new temp reg and return that reg. */
589 register rtx temp
= gen_reg_rtx (GET_MODE (x
));
591 /* If not an operand, must be an address with PLUS and MULT so
592 do the computation. */
593 if (! general_operand (x
, VOIDmode
))
594 x
= force_operand (x
, temp
);
597 emit_move_insn (temp
, x
);
602 /* Like copy_to_reg but always give the new register mode Pmode
603 in case X is a constant. */
609 return copy_to_mode_reg (Pmode
, x
);
612 /* Like copy_to_reg but always give the new register mode MODE
613 in case X is a constant. */
616 copy_to_mode_reg (mode
, x
)
617 enum machine_mode mode
;
620 register rtx temp
= gen_reg_rtx (mode
);
622 /* If not an operand, must be an address with PLUS and MULT so
623 do the computation. */
624 if (! general_operand (x
, VOIDmode
))
625 x
= force_operand (x
, temp
);
627 if (GET_MODE (x
) != mode
&& GET_MODE (x
) != VOIDmode
)
630 emit_move_insn (temp
, x
);
634 /* Load X into a register if it is not already one.
635 Use mode MODE for the register.
636 X should be valid for mode MODE, but it may be a constant which
637 is valid for all integer modes; that's why caller must specify MODE.
639 The caller must not alter the value in the register we return,
640 since we mark it as a "constant" register. */
644 enum machine_mode mode
;
647 register rtx temp
, insn
, set
;
649 if (GET_CODE (x
) == REG
)
651 temp
= gen_reg_rtx (mode
);
652 insn
= emit_move_insn (temp
, x
);
654 /* Let optimizers know that TEMP's value never changes
655 and that X can be substituted for it. Don't get confused
656 if INSN set something else (such as a SUBREG of TEMP). */
658 && (set
= single_set (insn
)) != 0
659 && SET_DEST (set
) == temp
)
661 rtx note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
666 REG_NOTES (insn
) = gen_rtx (EXPR_LIST
, REG_EQUAL
, x
, REG_NOTES (insn
));
671 /* If X is a memory ref, copy its contents to a new temp reg and return
672 that reg. Otherwise, return X. */
679 if (GET_CODE (x
) != MEM
|| GET_MODE (x
) == BLKmode
)
681 temp
= gen_reg_rtx (GET_MODE (x
));
682 emit_move_insn (temp
, x
);
686 /* Copy X to TARGET (if it's nonzero and a reg)
687 or to a new temp reg and return that reg.
688 MODE is the mode to use for X in case it is a constant. */
691 copy_to_suggested_reg (x
, target
, mode
)
693 enum machine_mode mode
;
697 if (target
&& GET_CODE (target
) == REG
)
700 temp
= gen_reg_rtx (mode
);
702 emit_move_insn (temp
, x
);
706 /* Return the mode to use to store a scalar of TYPE and MODE.
707 PUNSIGNEDP points to the signedness of the type and may be adjusted
708 to show what signedness to use on extension operations.
710 FOR_CALL is non-zero if this call is promoting args for a call. */
713 promote_mode (type
, mode
, punsignedp
, for_call
)
715 enum machine_mode mode
;
719 enum tree_code code
= TREE_CODE (type
);
720 int unsignedp
= *punsignedp
;
722 #ifdef PROMOTE_FOR_CALL_ONLY
730 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
731 case CHAR_TYPE
: case REAL_TYPE
: case OFFSET_TYPE
:
732 PROMOTE_MODE (mode
, unsignedp
, type
);
736 #ifdef POINTERS_EXTEND_UNSIGNED
740 unsignedp
= POINTERS_EXTEND_UNSIGNED
;
745 *punsignedp
= unsignedp
;
749 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
750 This pops when ADJUST is positive. ADJUST need not be constant. */
753 adjust_stack (adjust
)
757 adjust
= protect_from_queue (adjust
, 0);
759 if (adjust
== const0_rtx
)
762 temp
= expand_binop (Pmode
,
763 #ifdef STACK_GROWS_DOWNWARD
768 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
771 if (temp
!= stack_pointer_rtx
)
772 emit_move_insn (stack_pointer_rtx
, temp
);
775 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
776 This pushes when ADJUST is positive. ADJUST need not be constant. */
779 anti_adjust_stack (adjust
)
783 adjust
= protect_from_queue (adjust
, 0);
785 if (adjust
== const0_rtx
)
788 temp
= expand_binop (Pmode
,
789 #ifdef STACK_GROWS_DOWNWARD
794 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
797 if (temp
!= stack_pointer_rtx
)
798 emit_move_insn (stack_pointer_rtx
, temp
);
801 /* Round the size of a block to be pushed up to the boundary required
802 by this machine. SIZE is the desired size, which need not be constant. */
808 #ifdef STACK_BOUNDARY
809 int align
= STACK_BOUNDARY
/ BITS_PER_UNIT
;
812 if (GET_CODE (size
) == CONST_INT
)
814 int new = (INTVAL (size
) + align
- 1) / align
* align
;
815 if (INTVAL (size
) != new)
816 size
= GEN_INT (new);
820 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
821 but we know it can't. So add ourselves and then do
823 size
= expand_binop (Pmode
, add_optab
, size
, GEN_INT (align
- 1),
824 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
825 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
, GEN_INT (align
),
827 size
= expand_mult (Pmode
, size
, GEN_INT (align
), NULL_RTX
, 1);
829 #endif /* STACK_BOUNDARY */
833 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
834 to a previously-created save area. If no save area has been allocated,
835 this function will allocate one. If a save area is specified, it
836 must be of the proper mode.
838 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
839 are emitted at the current position. */
842 emit_stack_save (save_level
, psave
, after
)
843 enum save_level save_level
;
848 /* The default is that we use a move insn and save in a Pmode object. */
849 rtx (*fcn
) () = gen_move_insn
;
850 enum machine_mode mode
= Pmode
;
852 /* See if this machine has anything special to do for this kind of save. */
855 #ifdef HAVE_save_stack_block
857 if (HAVE_save_stack_block
)
859 fcn
= gen_save_stack_block
;
860 mode
= insn_operand_mode
[CODE_FOR_save_stack_block
][0];
864 #ifdef HAVE_save_stack_function
866 if (HAVE_save_stack_function
)
868 fcn
= gen_save_stack_function
;
869 mode
= insn_operand_mode
[CODE_FOR_save_stack_function
][0];
873 #ifdef HAVE_save_stack_nonlocal
875 if (HAVE_save_stack_nonlocal
)
877 fcn
= gen_save_stack_nonlocal
;
878 mode
= insn_operand_mode
[(int) CODE_FOR_save_stack_nonlocal
][0];
884 /* If there is no save area and we have to allocate one, do so. Otherwise
885 verify the save area is the proper mode. */
889 if (mode
!= VOIDmode
)
891 if (save_level
== SAVE_NONLOCAL
)
892 *psave
= sa
= assign_stack_local (mode
, GET_MODE_SIZE (mode
), 0);
894 *psave
= sa
= gen_reg_rtx (mode
);
899 if (mode
== VOIDmode
|| GET_MODE (sa
) != mode
)
908 /* We must validize inside the sequence, to ensure that any instructions
909 created by the validize call also get moved to the right place. */
911 sa
= validize_mem (sa
);
912 emit_insn (fcn (sa
, stack_pointer_rtx
));
913 seq
= gen_sequence ();
915 emit_insn_after (seq
, after
);
920 sa
= validize_mem (sa
);
921 emit_insn (fcn (sa
, stack_pointer_rtx
));
925 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
926 area made by emit_stack_save. If it is zero, we have nothing to do.
928 Put any emitted insns after insn AFTER, if nonzero, otherwise at
932 emit_stack_restore (save_level
, sa
, after
)
933 enum save_level save_level
;
937 /* The default is that we use a move insn. */
938 rtx (*fcn
) () = gen_move_insn
;
940 /* See if this machine has anything special to do for this kind of save. */
943 #ifdef HAVE_restore_stack_block
945 if (HAVE_restore_stack_block
)
946 fcn
= gen_restore_stack_block
;
949 #ifdef HAVE_restore_stack_function
951 if (HAVE_restore_stack_function
)
952 fcn
= gen_restore_stack_function
;
955 #ifdef HAVE_restore_stack_nonlocal
958 if (HAVE_restore_stack_nonlocal
)
959 fcn
= gen_restore_stack_nonlocal
;
965 sa
= validize_mem (sa
);
972 emit_insn (fcn (stack_pointer_rtx
, sa
));
973 seq
= gen_sequence ();
975 emit_insn_after (seq
, after
);
978 emit_insn (fcn (stack_pointer_rtx
, sa
));
981 /* Return an rtx representing the address of an area of memory dynamically
982 pushed on the stack. This region of memory is always aligned to
983 a multiple of BIGGEST_ALIGNMENT.
985 Any required stack pointer alignment is preserved.
987 SIZE is an rtx representing the size of the area.
988 TARGET is a place in which the address can be placed.
990 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
993 allocate_dynamic_stack_space (size
, target
, known_align
)
998 /* If we're asking for zero bytes, it doesn't matter what we point
999 to since we can't dereference it. But return a reasonable
1001 if (size
== const0_rtx
)
1002 return virtual_stack_dynamic_rtx
;
1004 /* Otherwise, show we're calling alloca or equivalent. */
1005 current_function_calls_alloca
= 1;
1007 /* Ensure the size is in the proper mode. */
1008 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1009 size
= convert_to_mode (Pmode
, size
, 1);
1011 /* We will need to ensure that the address we return is aligned to
1012 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1013 always know its final value at this point in the compilation (it
1014 might depend on the size of the outgoing parameter lists, for
1015 example), so we must align the value to be returned in that case.
1016 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if
1017 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1018 We must also do an alignment operation on the returned value if
1019 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1021 If we have to align, we must leave space in SIZE for the hole
1022 that might result from the alignment operation. */
1024 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) || ! defined (STACK_BOUNDARY)
1025 #define MUST_ALIGN 1
1027 #define MUST_ALIGN (STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1032 if (GET_CODE (size
) == CONST_INT
)
1033 size
= GEN_INT (INTVAL (size
)
1034 + (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1));
1036 size
= expand_binop (Pmode
, add_optab
, size
,
1037 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1038 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1041 #ifdef SETJMP_VIA_SAVE_AREA
1042 /* If setjmp restores regs from a save area in the stack frame,
1043 avoid clobbering the reg save area. Note that the offset of
1044 virtual_incoming_args_rtx includes the preallocated stack args space.
1045 It would be no problem to clobber that, but it's on the wrong side
1046 of the old save area. */
1049 = expand_binop (Pmode
, sub_optab
, virtual_stack_dynamic_rtx
,
1050 stack_pointer_rtx
, NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1051 size
= expand_binop (Pmode
, add_optab
, size
, dynamic_offset
,
1052 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1054 #endif /* SETJMP_VIA_SAVE_AREA */
1056 /* Round the size to a multiple of the required stack alignment.
1057 Since the stack if presumed to be rounded before this allocation,
1058 this will maintain the required alignment.
1060 If the stack grows downward, we could save an insn by subtracting
1061 SIZE from the stack pointer and then aligning the stack pointer.
1062 The problem with this is that the stack pointer may be unaligned
1063 between the execution of the subtraction and alignment insns and
1064 some machines do not allow this. Even on those that do, some
1065 signal handlers malfunction if a signal should occur between those
1066 insns. Since this is an extremely rare event, we have no reliable
1067 way of knowing which systems have this problem. So we avoid even
1068 momentarily mis-aligning the stack. */
1070 #ifdef STACK_BOUNDARY
1071 /* If we added a variable amount to SIZE,
1072 we can no longer assume it is aligned. */
1073 #if !defined (SETJMP_VIA_SAVE_AREA)
1074 if (MUST_ALIGN
|| known_align
% STACK_BOUNDARY
!= 0)
1076 size
= round_push (size
);
1079 do_pending_stack_adjust ();
1081 /* If needed, check that we have the required amount of stack. Take into
1082 account what has already been checked. */
1083 if (flag_stack_check
&& ! STACK_CHECK_BUILTIN
)
1084 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE
+ STACK_CHECK_PROTECT
, size
);
1086 /* Don't use a TARGET that isn't a pseudo. */
1087 if (target
== 0 || GET_CODE (target
) != REG
1088 || REGNO (target
) < FIRST_PSEUDO_REGISTER
)
1089 target
= gen_reg_rtx (Pmode
);
1091 mark_reg_pointer (target
, known_align
/ BITS_PER_UNIT
);
1093 #ifndef STACK_GROWS_DOWNWARD
1094 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1097 /* Perform the required allocation from the stack. Some systems do
1098 this differently than simply incrementing/decrementing from the
1100 #ifdef HAVE_allocate_stack
1101 if (HAVE_allocate_stack
)
1103 enum machine_mode mode
1104 = insn_operand_mode
[(int) CODE_FOR_allocate_stack
][0];
1106 size
= convert_modes (mode
, ptr_mode
, size
, 1);
1108 if (insn_operand_predicate
[(int) CODE_FOR_allocate_stack
][0]
1109 && ! ((*insn_operand_predicate
[(int) CODE_FOR_allocate_stack
][0])
1111 size
= copy_to_mode_reg (mode
, size
);
1113 emit_insn (gen_allocate_stack (size
));
1118 size
= convert_modes (Pmode
, ptr_mode
, size
, 1);
1119 anti_adjust_stack (size
);
1122 #ifdef STACK_GROWS_DOWNWARD
1123 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1128 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1129 but we know it can't. So add ourselves and then do
1131 target
= expand_binop (Pmode
, add_optab
, target
,
1132 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1133 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1134 target
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, target
,
1135 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1137 target
= expand_mult (Pmode
, target
,
1138 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1142 /* Some systems require a particular insn to refer to the stack
1143 to make the pages exist. */
1146 emit_insn (gen_probe ());
1149 /* Record the new stack level for nonlocal gotos. */
1150 if (nonlocal_goto_handler_slot
!= 0)
1151 emit_stack_save (SAVE_NONLOCAL
, &nonlocal_goto_stack_level
, NULL_RTX
);
1156 /* Emit one stack probe at ADDRESS, an address within the stack. */
1159 emit_stack_probe (address
)
1162 rtx memref
= gen_rtx (MEM
, word_mode
, address
);
1164 MEM_VOLATILE_P (memref
) = 1;
1166 if (STACK_CHECK_PROBE_LOAD
)
1167 emit_move_insn (gen_reg_rtx (word_mode
), memref
);
1169 emit_move_insn (memref
, const0_rtx
);
1172 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1173 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1174 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1175 subtract from the stack. If SIZE is constant, this is done
1176 with a fixed number of probes. Otherwise, we must make a loop. */
1178 #ifdef STACK_GROWS_DOWNWARD
1179 #define STACK_GROW_OP MINUS
1181 #define STACK_GROW_OP PLUS
1185 probe_stack_range (first
, size
)
1186 HOST_WIDE_INT first
;
1189 /* First see if we have an insn to check the stack. Use it if so. */
1190 #ifdef HAVE_check_stack
1191 if (HAVE_check_stack
)
1193 rtx last_addr
= force_operand (gen_rtx (STACK_GROW_OP
, Pmode
,
1195 plus_constant (size
, first
)),
1198 if (insn_operand_predicate
[(int) CODE_FOR_check_stack
][0]
1199 && ! ((*insn_operand_predicate
[(int) CODE_FOR_check_stack
][0])
1200 (last_address
, Pmode
)))
1201 last_address
= copy_to_mode_reg (Pmode
, last_address
);
1203 emit_insn (gen_check_stack (last_address
));
1208 /* If we have to generate explicit probes, see if we have a constant
1209 small number of them to generate. If so, that's the easy case. */
1210 if (GET_CODE (size
) == CONST_INT
&& INTVAL (size
) < 10)
1212 HOST_WIDE_INT offset
;
1214 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1215 for values of N from 1 until it exceeds LAST. If only one
1216 probe is needed, this will not generate any code. Then probe
1218 for (offset
= first
+ STACK_CHECK_PROBE_INTERVAL
;
1219 offset
< INTVAL (size
);
1220 offset
= offset
+ STACK_CHECK_PROBE_INTERVAL
)
1221 emit_stack_probe (gen_rtx (STACK_GROW_OP
, Pmode
,
1222 stack_pointer_rtx
, GEN_INT (offset
)));
1224 emit_stack_probe (gen_rtx (STACK_GROW_OP
, Pmode
, stack_pointer_rtx
,
1225 plus_constant (size
, first
)));
1228 /* In the variable case, do the same as above, but in a loop. We emit loop
1229 notes so that loop optimization can be done. */
1233 = force_operand (gen_rtx (STACK_GROW_OP
, Pmode
, stack_pointer_rtx
,
1235 + STACK_CHECK_PROBE_INTERVAL
)),
1238 = force_operand (gen_rtx (STACK_GROW_OP
, Pmode
, stack_pointer_rtx
,
1239 plus_constant (size
, first
)),
1241 rtx incr
= GEN_INT (STACK_CHECK_PROBE_INTERVAL
);
1242 rtx loop_lab
= gen_label_rtx ();
1243 rtx test_lab
= gen_label_rtx ();
1244 rtx end_lab
= gen_label_rtx ();
1247 if (GET_CODE (test_addr
) != REG
1248 || REGNO (test_addr
) < FIRST_PSEUDO_REGISTER
)
1249 test_addr
= force_reg (Pmode
, test_addr
);
1251 emit_note (NULL_PTR
, NOTE_INSN_LOOP_BEG
);
1252 emit_jump (test_lab
);
1254 emit_label (loop_lab
);
1255 emit_stack_probe (test_addr
);
1257 emit_note (NULL_PTR
, NOTE_INSN_LOOP_CONT
);
1259 #ifdef STACK_GROWS_DOWNWARD
1260 #define CMP_OPCODE GTU
1261 temp
= expand_binop (Pmode
, sub_optab
, test_addr
, incr
, test_addr
,
1264 #define CMP_OPCODE LTU
1265 temp
= expand_binop (Pmode
, add_optab
, test_addr
, incr
, test_addr
,
1269 if (temp
!= test_addr
)
1272 emit_label (test_lab
);
1273 emit_cmp_insn (test_addr
, last_addr
, CMP_OPCODE
, NULL_RTX
, Pmode
, 1, 0);
1274 emit_jump_insn ((*bcc_gen_fctn
[(int) CMP_OPCODE
]) (loop_lab
));
1275 emit_jump (end_lab
);
1276 emit_note (NULL_PTR
, NOTE_INSN_LOOP_END
);
1277 emit_label (end_lab
);
1279 emit_stack_probe (last_addr
);
1283 /* Return an rtx representing the register or memory location
1284 in which a scalar value of data type VALTYPE
1285 was returned by a function call to function FUNC.
1286 FUNC is a FUNCTION_DECL node if the precise function is known,
1290 hard_function_value (valtype
, func
)
1294 rtx val
= FUNCTION_VALUE (valtype
, func
);
1295 if (GET_CODE (val
) == REG
1296 && GET_MODE (val
) == BLKmode
)
1298 int bytes
= int_size_in_bytes (valtype
);
1299 enum machine_mode tmpmode
;
1300 for (tmpmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
1301 tmpmode
!= MAX_MACHINE_MODE
;
1302 tmpmode
= GET_MODE_WIDER_MODE (tmpmode
))
1304 /* Have we found a large enough mode? */
1305 if (GET_MODE_SIZE (tmpmode
) >= bytes
)
1309 /* No suitable mode found. */
1310 if (tmpmode
== MAX_MACHINE_MODE
)
1313 PUT_MODE (val
, tmpmode
);
1318 /* Return an rtx representing the register or memory location
1319 in which a scalar value of mode MODE was returned by a library call. */
1322 hard_libcall_value (mode
)
1323 enum machine_mode mode
;
1325 return LIBCALL_VALUE (mode
);
1328 /* Look up the tree code for a given rtx code
1329 to provide the arithmetic operation for REAL_ARITHMETIC.
1330 The function returns an int because the caller may not know
1331 what `enum tree_code' means. */
1334 rtx_to_tree_code (code
)
1337 enum tree_code tcode
;
1360 tcode
= LAST_AND_UNUSED_TREE_CODE
;
1363 return ((int) tcode
);