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.
6 This file is part of GCC.
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
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
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
26 #include "coretypes.h"
36 #include "hard-reg-set.h"
37 #include "insn-config.h"
40 #include "langhooks.h"
43 static rtx
break_out_memory_refs (rtx
);
44 static void emit_stack_probe (rtx
);
47 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
50 trunc_int_for_mode (HOST_WIDE_INT c
, enum machine_mode mode
)
52 int width
= GET_MODE_BITSIZE (mode
);
54 /* You want to truncate to a _what_? */
55 gcc_assert (SCALAR_INT_MODE_P (mode
));
57 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
59 return c
& 1 ? STORE_FLAG_VALUE
: 0;
61 /* Sign-extend for the requested mode. */
63 if (width
< HOST_BITS_PER_WIDE_INT
)
65 HOST_WIDE_INT sign
= 1;
75 /* Return an rtx for the sum of X and the integer C. */
78 plus_constant (rtx x
, HOST_WIDE_INT c
)
82 enum machine_mode mode
;
98 return GEN_INT (INTVAL (x
) + c
);
102 unsigned HOST_WIDE_INT l1
= CONST_DOUBLE_LOW (x
);
103 HOST_WIDE_INT h1
= CONST_DOUBLE_HIGH (x
);
104 unsigned HOST_WIDE_INT l2
= c
;
105 HOST_WIDE_INT h2
= c
< 0 ? ~0 : 0;
106 unsigned HOST_WIDE_INT lv
;
109 add_double (l1
, h1
, l2
, h2
, &lv
, &hv
);
111 return immed_double_const (lv
, hv
, VOIDmode
);
115 /* If this is a reference to the constant pool, try replacing it with
116 a reference to a new constant. If the resulting address isn't
117 valid, don't return it because we have no way to validize it. */
118 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
119 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
122 = force_const_mem (GET_MODE (x
),
123 plus_constant (get_pool_constant (XEXP (x
, 0)),
125 if (memory_address_p (GET_MODE (tem
), XEXP (tem
, 0)))
131 /* If adding to something entirely constant, set a flag
132 so that we can add a CONST around the result. */
143 /* The interesting case is adding the integer to a sum.
144 Look for constant term in the sum and combine
145 with C. For an integer constant term, we make a combined
146 integer. For a constant term that is not an explicit integer,
147 we cannot really combine, but group them together anyway.
149 Restart or use a recursive call in case the remaining operand is
150 something that we handle specially, such as a SYMBOL_REF.
152 We may not immediately return from the recursive call here, lest
153 all_constant gets lost. */
155 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
)
157 c
+= INTVAL (XEXP (x
, 1));
159 if (GET_MODE (x
) != VOIDmode
)
160 c
= trunc_int_for_mode (c
, GET_MODE (x
));
165 else if (CONSTANT_P (XEXP (x
, 1)))
167 x
= gen_rtx_PLUS (mode
, XEXP (x
, 0), plus_constant (XEXP (x
, 1), c
));
170 else if (find_constant_term_loc (&y
))
172 /* We need to be careful since X may be shared and we can't
173 modify it in place. */
174 rtx copy
= copy_rtx (x
);
175 rtx
*const_loc
= find_constant_term_loc (©
);
177 *const_loc
= plus_constant (*const_loc
, c
);
188 x
= gen_rtx_PLUS (mode
, x
, GEN_INT (c
));
190 if (GET_CODE (x
) == SYMBOL_REF
|| GET_CODE (x
) == LABEL_REF
)
192 else if (all_constant
)
193 return gen_rtx_CONST (mode
, x
);
198 /* If X is a sum, return a new sum like X but lacking any constant terms.
199 Add all the removed constant terms into *CONSTPTR.
200 X itself is not altered. The result != X if and only if
201 it is not isomorphic to X. */
204 eliminate_constant_term (rtx x
, rtx
*constptr
)
209 if (GET_CODE (x
) != PLUS
)
212 /* First handle constants appearing at this level explicitly. */
213 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
214 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
), *constptr
,
216 && GET_CODE (tem
) == CONST_INT
)
219 return eliminate_constant_term (XEXP (x
, 0), constptr
);
223 x0
= eliminate_constant_term (XEXP (x
, 0), &tem
);
224 x1
= eliminate_constant_term (XEXP (x
, 1), &tem
);
225 if ((x1
!= XEXP (x
, 1) || x0
!= XEXP (x
, 0))
226 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
),
228 && GET_CODE (tem
) == CONST_INT
)
231 return gen_rtx_PLUS (GET_MODE (x
), x0
, x1
);
237 /* Return an rtx for the size in bytes of the value of EXP. */
244 if (TREE_CODE (exp
) == WITH_SIZE_EXPR
)
245 size
= TREE_OPERAND (exp
, 1);
247 size
= SUBSTITUTE_PLACEHOLDER_IN_EXPR (lang_hooks
.expr_size (exp
), exp
);
249 return expand_expr (size
, NULL_RTX
, TYPE_MODE (sizetype
), 0);
252 /* Return a wide integer for the size in bytes of the value of EXP, or -1
253 if the size can vary or is larger than an integer. */
256 int_expr_size (tree exp
)
260 if (TREE_CODE (exp
) == WITH_SIZE_EXPR
)
261 size
= TREE_OPERAND (exp
, 1);
263 size
= lang_hooks
.expr_size (exp
);
265 if (size
== 0 || !host_integerp (size
, 0))
268 return tree_low_cst (size
, 0);
271 /* Return a copy of X in which all memory references
272 and all constants that involve symbol refs
273 have been replaced with new temporary registers.
274 Also emit code to load the memory locations and constants
275 into those registers.
277 If X contains no such constants or memory references,
278 X itself (not a copy) is returned.
280 If a constant is found in the address that is not a legitimate constant
281 in an insn, it is left alone in the hope that it might be valid in the
284 X may contain no arithmetic except addition, subtraction and multiplication.
285 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
288 break_out_memory_refs (rtx x
)
291 || (CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
)
292 && GET_MODE (x
) != VOIDmode
))
293 x
= force_reg (GET_MODE (x
), x
);
294 else if (GET_CODE (x
) == PLUS
|| GET_CODE (x
) == MINUS
295 || GET_CODE (x
) == MULT
)
297 rtx op0
= break_out_memory_refs (XEXP (x
, 0));
298 rtx op1
= break_out_memory_refs (XEXP (x
, 1));
300 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
301 x
= gen_rtx_fmt_ee (GET_CODE (x
), Pmode
, op0
, op1
);
307 /* Given X, a memory address in ptr_mode, convert it to an address
308 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
309 the fact that pointers are not allowed to overflow by commuting arithmetic
310 operations over conversions so that address arithmetic insns can be
314 convert_memory_address (enum machine_mode to_mode ATTRIBUTE_UNUSED
,
317 #ifndef POINTERS_EXTEND_UNSIGNED
318 gcc_assert (GET_MODE (x
) == to_mode
|| GET_MODE (x
) == VOIDmode
);
320 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
321 enum machine_mode from_mode
;
325 /* If X already has the right mode, just return it. */
326 if (GET_MODE (x
) == to_mode
)
329 from_mode
= to_mode
== ptr_mode
? Pmode
: ptr_mode
;
331 /* Here we handle some special cases. If none of them apply, fall through
332 to the default case. */
333 switch (GET_CODE (x
))
337 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
))
339 else if (POINTERS_EXTEND_UNSIGNED
< 0)
341 else if (POINTERS_EXTEND_UNSIGNED
> 0)
345 temp
= simplify_unary_operation (code
, to_mode
, x
, from_mode
);
351 if ((SUBREG_PROMOTED_VAR_P (x
) || REG_POINTER (SUBREG_REG (x
)))
352 && GET_MODE (SUBREG_REG (x
)) == to_mode
)
353 return SUBREG_REG (x
);
357 temp
= gen_rtx_LABEL_REF (to_mode
, XEXP (x
, 0));
358 LABEL_REF_NONLOCAL_P (temp
) = LABEL_REF_NONLOCAL_P (x
);
363 temp
= shallow_copy_rtx (x
);
364 PUT_MODE (temp
, to_mode
);
369 return gen_rtx_CONST (to_mode
,
370 convert_memory_address (to_mode
, XEXP (x
, 0)));
375 /* For addition we can safely permute the conversion and addition
376 operation if one operand is a constant and converting the constant
377 does not change it. We can always safely permute them if we are
378 making the address narrower. */
379 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
)
380 || (GET_CODE (x
) == PLUS
381 && GET_CODE (XEXP (x
, 1)) == CONST_INT
382 && XEXP (x
, 1) == convert_memory_address (to_mode
, XEXP (x
, 1))))
383 return gen_rtx_fmt_ee (GET_CODE (x
), to_mode
,
384 convert_memory_address (to_mode
, XEXP (x
, 0)),
392 return convert_modes (to_mode
, from_mode
,
393 x
, POINTERS_EXTEND_UNSIGNED
);
394 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
397 /* Return something equivalent to X but valid as a memory address
398 for something of mode MODE. When X is not itself valid, this
399 works by copying X or subexpressions of it into registers. */
402 memory_address (enum machine_mode mode
, rtx x
)
406 x
= convert_memory_address (Pmode
, x
);
408 /* By passing constant addresses through registers
409 we get a chance to cse them. */
410 if (! cse_not_expected
&& CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
))
411 x
= force_reg (Pmode
, x
);
413 /* We get better cse by rejecting indirect addressing at this stage.
414 Let the combiner create indirect addresses where appropriate.
415 For now, generate the code so that the subexpressions useful to share
416 are visible. But not if cse won't be done! */
419 if (! cse_not_expected
&& !REG_P (x
))
420 x
= break_out_memory_refs (x
);
422 /* At this point, any valid address is accepted. */
423 if (memory_address_p (mode
, x
))
426 /* If it was valid before but breaking out memory refs invalidated it,
427 use it the old way. */
428 if (memory_address_p (mode
, oldx
))
431 /* Perform machine-dependent transformations on X
432 in certain cases. This is not necessary since the code
433 below can handle all possible cases, but machine-dependent
434 transformations can make better code. */
435 LEGITIMIZE_ADDRESS (x
, oldx
, mode
, win
);
437 /* PLUS and MULT can appear in special ways
438 as the result of attempts to make an address usable for indexing.
439 Usually they are dealt with by calling force_operand, below.
440 But a sum containing constant terms is special
441 if removing them makes the sum a valid address:
442 then we generate that address in a register
443 and index off of it. We do this because it often makes
444 shorter code, and because the addresses thus generated
445 in registers often become common subexpressions. */
446 if (GET_CODE (x
) == PLUS
)
448 rtx constant_term
= const0_rtx
;
449 rtx y
= eliminate_constant_term (x
, &constant_term
);
450 if (constant_term
== const0_rtx
451 || ! memory_address_p (mode
, y
))
452 x
= force_operand (x
, NULL_RTX
);
455 y
= gen_rtx_PLUS (GET_MODE (x
), copy_to_reg (y
), constant_term
);
456 if (! memory_address_p (mode
, y
))
457 x
= force_operand (x
, NULL_RTX
);
463 else if (GET_CODE (x
) == MULT
|| GET_CODE (x
) == MINUS
)
464 x
= force_operand (x
, NULL_RTX
);
466 /* If we have a register that's an invalid address,
467 it must be a hard reg of the wrong class. Copy it to a pseudo. */
471 /* Last resort: copy the value to a register, since
472 the register is a valid address. */
474 x
= force_reg (Pmode
, x
);
481 if (flag_force_addr
&& ! cse_not_expected
&& !REG_P (x
))
483 x
= force_operand (x
, NULL_RTX
);
484 x
= force_reg (Pmode
, x
);
490 /* If we didn't change the address, we are done. Otherwise, mark
491 a reg as a pointer if we have REG or REG + CONST_INT. */
495 mark_reg_pointer (x
, BITS_PER_UNIT
);
496 else if (GET_CODE (x
) == PLUS
497 && REG_P (XEXP (x
, 0))
498 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
499 mark_reg_pointer (XEXP (x
, 0), BITS_PER_UNIT
);
501 /* OLDX may have been the address on a temporary. Update the address
502 to indicate that X is now used. */
503 update_temp_slot_address (oldx
, x
);
508 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
511 memory_address_noforce (enum machine_mode mode
, rtx x
)
513 int ambient_force_addr
= flag_force_addr
;
517 val
= memory_address (mode
, x
);
518 flag_force_addr
= ambient_force_addr
;
522 /* Convert a mem ref into one with a valid memory address.
523 Pass through anything else unchanged. */
526 validize_mem (rtx ref
)
530 if (! (flag_force_addr
&& CONSTANT_ADDRESS_P (XEXP (ref
, 0)))
531 && memory_address_p (GET_MODE (ref
), XEXP (ref
, 0)))
534 /* Don't alter REF itself, since that is probably a stack slot. */
535 return replace_equiv_address (ref
, XEXP (ref
, 0));
538 /* Copy the value or contents of X to a new temp reg and return that reg. */
543 rtx temp
= gen_reg_rtx (GET_MODE (x
));
545 /* If not an operand, must be an address with PLUS and MULT so
546 do the computation. */
547 if (! general_operand (x
, VOIDmode
))
548 x
= force_operand (x
, temp
);
551 emit_move_insn (temp
, x
);
556 /* Like copy_to_reg but always give the new register mode Pmode
557 in case X is a constant. */
560 copy_addr_to_reg (rtx x
)
562 return copy_to_mode_reg (Pmode
, x
);
565 /* Like copy_to_reg but always give the new register mode MODE
566 in case X is a constant. */
569 copy_to_mode_reg (enum machine_mode mode
, rtx x
)
571 rtx temp
= gen_reg_rtx (mode
);
573 /* If not an operand, must be an address with PLUS and MULT so
574 do the computation. */
575 if (! general_operand (x
, VOIDmode
))
576 x
= force_operand (x
, temp
);
578 gcc_assert (GET_MODE (x
) == mode
|| GET_MODE (x
) == VOIDmode
);
580 emit_move_insn (temp
, x
);
584 /* Load X into a register if it is not already one.
585 Use mode MODE for the register.
586 X should be valid for mode MODE, but it may be a constant which
587 is valid for all integer modes; that's why caller must specify MODE.
589 The caller must not alter the value in the register we return,
590 since we mark it as a "constant" register. */
593 force_reg (enum machine_mode mode
, rtx x
)
600 if (general_operand (x
, mode
))
602 temp
= gen_reg_rtx (mode
);
603 insn
= emit_move_insn (temp
, x
);
607 temp
= force_operand (x
, NULL_RTX
);
609 insn
= get_last_insn ();
612 rtx temp2
= gen_reg_rtx (mode
);
613 insn
= emit_move_insn (temp2
, temp
);
618 /* Let optimizers know that TEMP's value never changes
619 and that X can be substituted for it. Don't get confused
620 if INSN set something else (such as a SUBREG of TEMP). */
622 && (set
= single_set (insn
)) != 0
623 && SET_DEST (set
) == temp
624 && ! rtx_equal_p (x
, SET_SRC (set
)))
625 set_unique_reg_note (insn
, REG_EQUAL
, x
);
627 /* Let optimizers know that TEMP is a pointer, and if so, the
628 known alignment of that pointer. */
631 if (GET_CODE (x
) == SYMBOL_REF
)
633 align
= BITS_PER_UNIT
;
634 if (SYMBOL_REF_DECL (x
) && DECL_P (SYMBOL_REF_DECL (x
)))
635 align
= DECL_ALIGN (SYMBOL_REF_DECL (x
));
637 else if (GET_CODE (x
) == LABEL_REF
)
638 align
= BITS_PER_UNIT
;
639 else if (GET_CODE (x
) == CONST
640 && GET_CODE (XEXP (x
, 0)) == PLUS
641 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == SYMBOL_REF
642 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
)
644 rtx s
= XEXP (XEXP (x
, 0), 0);
645 rtx c
= XEXP (XEXP (x
, 0), 1);
649 if (SYMBOL_REF_DECL (s
) && DECL_P (SYMBOL_REF_DECL (s
)))
650 sa
= DECL_ALIGN (SYMBOL_REF_DECL (s
));
652 ca
= exact_log2 (INTVAL (c
) & -INTVAL (c
)) * BITS_PER_UNIT
;
654 align
= MIN (sa
, ca
);
658 mark_reg_pointer (temp
, align
);
664 /* If X is a memory ref, copy its contents to a new temp reg and return
665 that reg. Otherwise, return X. */
668 force_not_mem (rtx x
)
672 if (!MEM_P (x
) || GET_MODE (x
) == BLKmode
)
675 temp
= gen_reg_rtx (GET_MODE (x
));
678 REG_POINTER (temp
) = 1;
680 emit_move_insn (temp
, x
);
684 /* Copy X to TARGET (if it's nonzero and a reg)
685 or to a new temp reg and return that reg.
686 MODE is the mode to use for X in case it is a constant. */
689 copy_to_suggested_reg (rtx x
, rtx target
, enum machine_mode mode
)
693 if (target
&& REG_P (target
))
696 temp
= gen_reg_rtx (mode
);
698 emit_move_insn (temp
, x
);
702 /* Return the mode to use to store a scalar of TYPE and MODE.
703 PUNSIGNEDP points to the signedness of the type and may be adjusted
704 to show what signedness to use on extension operations.
706 FOR_CALL is nonzero if this call is promoting args for a call. */
708 #if defined(PROMOTE_MODE) && !defined(PROMOTE_FUNCTION_MODE)
709 #define PROMOTE_FUNCTION_MODE PROMOTE_MODE
713 promote_mode (tree type
, enum machine_mode mode
, int *punsignedp
,
714 int for_call ATTRIBUTE_UNUSED
)
716 enum tree_code code
= TREE_CODE (type
);
717 int unsignedp
= *punsignedp
;
726 #ifdef PROMOTE_FUNCTION_MODE
727 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
728 case REAL_TYPE
: case OFFSET_TYPE
:
733 PROMOTE_FUNCTION_MODE (mode
, unsignedp
, type
);
738 PROMOTE_MODE (mode
, unsignedp
, type
);
744 #ifdef POINTERS_EXTEND_UNSIGNED
748 unsignedp
= POINTERS_EXTEND_UNSIGNED
;
756 *punsignedp
= unsignedp
;
760 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
761 This pops when ADJUST is positive. ADJUST need not be constant. */
764 adjust_stack (rtx adjust
)
768 if (adjust
== const0_rtx
)
771 /* We expect all variable sized adjustments to be multiple of
772 PREFERRED_STACK_BOUNDARY. */
773 if (GET_CODE (adjust
) == CONST_INT
)
774 stack_pointer_delta
-= INTVAL (adjust
);
776 temp
= expand_binop (Pmode
,
777 #ifdef STACK_GROWS_DOWNWARD
782 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
785 if (temp
!= stack_pointer_rtx
)
786 emit_move_insn (stack_pointer_rtx
, temp
);
789 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
790 This pushes when ADJUST is positive. ADJUST need not be constant. */
793 anti_adjust_stack (rtx adjust
)
797 if (adjust
== const0_rtx
)
800 /* We expect all variable sized adjustments to be multiple of
801 PREFERRED_STACK_BOUNDARY. */
802 if (GET_CODE (adjust
) == CONST_INT
)
803 stack_pointer_delta
+= INTVAL (adjust
);
805 temp
= expand_binop (Pmode
,
806 #ifdef STACK_GROWS_DOWNWARD
811 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
814 if (temp
!= stack_pointer_rtx
)
815 emit_move_insn (stack_pointer_rtx
, temp
);
818 /* Round the size of a block to be pushed up to the boundary required
819 by this machine. SIZE is the desired size, which need not be constant. */
822 round_push (rtx size
)
824 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
829 if (GET_CODE (size
) == CONST_INT
)
831 HOST_WIDE_INT
new = (INTVAL (size
) + align
- 1) / align
* align
;
833 if (INTVAL (size
) != new)
834 size
= GEN_INT (new);
838 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
839 but we know it can't. So add ourselves and then do
841 size
= expand_binop (Pmode
, add_optab
, size
, GEN_INT (align
- 1),
842 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
843 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
, GEN_INT (align
),
845 size
= expand_mult (Pmode
, size
, GEN_INT (align
), NULL_RTX
, 1);
851 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
852 to a previously-created save area. If no save area has been allocated,
853 this function will allocate one. If a save area is specified, it
854 must be of the proper mode.
856 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
857 are emitted at the current position. */
860 emit_stack_save (enum save_level save_level
, rtx
*psave
, rtx after
)
863 /* The default is that we use a move insn and save in a Pmode object. */
864 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
865 enum machine_mode mode
= STACK_SAVEAREA_MODE (save_level
);
867 /* See if this machine has anything special to do for this kind of save. */
870 #ifdef HAVE_save_stack_block
872 if (HAVE_save_stack_block
)
873 fcn
= gen_save_stack_block
;
876 #ifdef HAVE_save_stack_function
878 if (HAVE_save_stack_function
)
879 fcn
= gen_save_stack_function
;
882 #ifdef HAVE_save_stack_nonlocal
884 if (HAVE_save_stack_nonlocal
)
885 fcn
= gen_save_stack_nonlocal
;
892 /* If there is no save area and we have to allocate one, do so. Otherwise
893 verify the save area is the proper mode. */
897 if (mode
!= VOIDmode
)
899 if (save_level
== SAVE_NONLOCAL
)
900 *psave
= sa
= assign_stack_local (mode
, GET_MODE_SIZE (mode
), 0);
902 *psave
= sa
= gen_reg_rtx (mode
);
911 do_pending_stack_adjust ();
912 /* We must validize inside the sequence, to ensure that any instructions
913 created by the validize call also get moved to the right place. */
915 sa
= validize_mem (sa
);
916 emit_insn (fcn (sa
, stack_pointer_rtx
));
919 emit_insn_after (seq
, after
);
923 do_pending_stack_adjust ();
925 sa
= validize_mem (sa
);
926 emit_insn (fcn (sa
, stack_pointer_rtx
));
930 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
931 area made by emit_stack_save. If it is zero, we have nothing to do.
933 Put any emitted insns after insn AFTER, if nonzero, otherwise at
937 emit_stack_restore (enum save_level save_level
, rtx sa
, rtx after
)
939 /* The default is that we use a move insn. */
940 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
942 /* See if this machine has anything special to do for this kind of save. */
945 #ifdef HAVE_restore_stack_block
947 if (HAVE_restore_stack_block
)
948 fcn
= gen_restore_stack_block
;
951 #ifdef HAVE_restore_stack_function
953 if (HAVE_restore_stack_function
)
954 fcn
= gen_restore_stack_function
;
957 #ifdef HAVE_restore_stack_nonlocal
959 if (HAVE_restore_stack_nonlocal
)
960 fcn
= gen_restore_stack_nonlocal
;
969 sa
= validize_mem (sa
);
970 /* These clobbers prevent the scheduler from moving
971 references to variable arrays below the code
972 that deletes (pops) the arrays. */
973 emit_insn (gen_rtx_CLOBBER (VOIDmode
,
974 gen_rtx_MEM (BLKmode
,
975 gen_rtx_SCRATCH (VOIDmode
))));
976 emit_insn (gen_rtx_CLOBBER (VOIDmode
,
977 gen_rtx_MEM (BLKmode
, stack_pointer_rtx
)));
980 discard_pending_stack_adjust ();
987 emit_insn (fcn (stack_pointer_rtx
, sa
));
990 emit_insn_after (seq
, after
);
993 emit_insn (fcn (stack_pointer_rtx
, sa
));
996 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
997 function. This function should be called whenever we allocate or
998 deallocate dynamic stack space. */
1001 update_nonlocal_goto_save_area (void)
1006 /* The nonlocal_goto_save_area object is an array of N pointers. The
1007 first one is used for the frame pointer save; the rest are sized by
1008 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1009 of the stack save area slots. */
1010 t_save
= build4 (ARRAY_REF
, ptr_type_node
, cfun
->nonlocal_goto_save_area
,
1011 integer_one_node
, NULL_TREE
, NULL_TREE
);
1012 r_save
= expand_expr (t_save
, NULL_RTX
, VOIDmode
, EXPAND_WRITE
);
1014 emit_stack_save (SAVE_NONLOCAL
, &r_save
, NULL_RTX
);
1017 /* Return an rtx representing the address of an area of memory dynamically
1018 pushed on the stack. This region of memory is always aligned to
1019 a multiple of BIGGEST_ALIGNMENT.
1021 Any required stack pointer alignment is preserved.
1023 SIZE is an rtx representing the size of the area.
1024 TARGET is a place in which the address can be placed.
1026 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1029 allocate_dynamic_stack_space (rtx size
, rtx target
, int known_align
)
1031 /* If we're asking for zero bytes, it doesn't matter what we point
1032 to since we can't dereference it. But return a reasonable
1034 if (size
== const0_rtx
)
1035 return virtual_stack_dynamic_rtx
;
1037 /* Otherwise, show we're calling alloca or equivalent. */
1038 current_function_calls_alloca
= 1;
1040 /* Ensure the size is in the proper mode. */
1041 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1042 size
= convert_to_mode (Pmode
, size
, 1);
1044 /* We can't attempt to minimize alignment necessary, because we don't
1045 know the final value of preferred_stack_boundary yet while executing
1047 cfun
->preferred_stack_boundary
= PREFERRED_STACK_BOUNDARY
;
1049 /* We will need to ensure that the address we return is aligned to
1050 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1051 always know its final value at this point in the compilation (it
1052 might depend on the size of the outgoing parameter lists, for
1053 example), so we must align the value to be returned in that case.
1054 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1055 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1056 We must also do an alignment operation on the returned value if
1057 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1059 If we have to align, we must leave space in SIZE for the hole
1060 that might result from the alignment operation. */
1062 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1063 #define MUST_ALIGN 1
1065 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1070 = force_operand (plus_constant (size
,
1071 BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1074 #ifdef SETJMP_VIA_SAVE_AREA
1075 /* If setjmp restores regs from a save area in the stack frame,
1076 avoid clobbering the reg save area. Note that the offset of
1077 virtual_incoming_args_rtx includes the preallocated stack args space.
1078 It would be no problem to clobber that, but it's on the wrong side
1079 of the old save area.
1081 What used to happen is that, since we did not know for sure
1082 whether setjmp() was invoked until after RTL generation, we
1083 would use reg notes to store the "optimized" size and fix things
1084 up later. These days we know this information before we ever
1085 start building RTL so the reg notes are unnecessary. */
1086 if (!current_function_calls_setjmp
)
1088 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
1090 /* ??? Code below assumes that the save area needs maximal
1091 alignment. This constraint may be too strong. */
1092 gcc_assert (PREFERRED_STACK_BOUNDARY
== BIGGEST_ALIGNMENT
);
1094 if (GET_CODE (size
) == CONST_INT
)
1096 HOST_WIDE_INT
new = INTVAL (size
) / align
* align
;
1098 if (INTVAL (size
) != new)
1099 size
= GEN_INT (new);
1103 /* Since we know overflow is not possible, we avoid using
1104 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1105 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
,
1106 GEN_INT (align
), NULL_RTX
, 1);
1107 size
= expand_mult (Pmode
, size
,
1108 GEN_INT (align
), NULL_RTX
, 1);
1114 = expand_binop (Pmode
, sub_optab
, virtual_stack_dynamic_rtx
,
1115 stack_pointer_rtx
, NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1117 size
= expand_binop (Pmode
, add_optab
, size
, dynamic_offset
,
1118 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1120 #endif /* SETJMP_VIA_SAVE_AREA */
1122 /* Round the size to a multiple of the required stack alignment.
1123 Since the stack if presumed to be rounded before this allocation,
1124 this will maintain the required alignment.
1126 If the stack grows downward, we could save an insn by subtracting
1127 SIZE from the stack pointer and then aligning the stack pointer.
1128 The problem with this is that the stack pointer may be unaligned
1129 between the execution of the subtraction and alignment insns and
1130 some machines do not allow this. Even on those that do, some
1131 signal handlers malfunction if a signal should occur between those
1132 insns. Since this is an extremely rare event, we have no reliable
1133 way of knowing which systems have this problem. So we avoid even
1134 momentarily mis-aligning the stack. */
1136 /* If we added a variable amount to SIZE,
1137 we can no longer assume it is aligned. */
1138 #if !defined (SETJMP_VIA_SAVE_AREA)
1139 if (MUST_ALIGN
|| known_align
% PREFERRED_STACK_BOUNDARY
!= 0)
1141 size
= round_push (size
);
1143 do_pending_stack_adjust ();
1145 /* We ought to be called always on the toplevel and stack ought to be aligned
1147 gcc_assert (!(stack_pointer_delta
1148 % (PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
)));
1150 /* If needed, check that we have the required amount of stack. Take into
1151 account what has already been checked. */
1152 if (flag_stack_check
&& ! STACK_CHECK_BUILTIN
)
1153 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE
+ STACK_CHECK_PROTECT
, size
);
1155 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1156 if (target
== 0 || !REG_P (target
)
1157 || REGNO (target
) < FIRST_PSEUDO_REGISTER
1158 || GET_MODE (target
) != Pmode
)
1159 target
= gen_reg_rtx (Pmode
);
1161 mark_reg_pointer (target
, known_align
);
1163 /* Perform the required allocation from the stack. Some systems do
1164 this differently than simply incrementing/decrementing from the
1165 stack pointer, such as acquiring the space by calling malloc(). */
1166 #ifdef HAVE_allocate_stack
1167 if (HAVE_allocate_stack
)
1169 enum machine_mode mode
= STACK_SIZE_MODE
;
1170 insn_operand_predicate_fn pred
;
1172 /* We don't have to check against the predicate for operand 0 since
1173 TARGET is known to be a pseudo of the proper mode, which must
1174 be valid for the operand. For operand 1, convert to the
1175 proper mode and validate. */
1176 if (mode
== VOIDmode
)
1177 mode
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].mode
;
1179 pred
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].predicate
;
1180 if (pred
&& ! ((*pred
) (size
, mode
)))
1181 size
= copy_to_mode_reg (mode
, convert_to_mode (mode
, size
, 1));
1183 emit_insn (gen_allocate_stack (target
, size
));
1188 #ifndef STACK_GROWS_DOWNWARD
1189 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1192 /* Check stack bounds if necessary. */
1193 if (current_function_limit_stack
)
1196 rtx space_available
= gen_label_rtx ();
1197 #ifdef STACK_GROWS_DOWNWARD
1198 available
= expand_binop (Pmode
, sub_optab
,
1199 stack_pointer_rtx
, stack_limit_rtx
,
1200 NULL_RTX
, 1, OPTAB_WIDEN
);
1202 available
= expand_binop (Pmode
, sub_optab
,
1203 stack_limit_rtx
, stack_pointer_rtx
,
1204 NULL_RTX
, 1, OPTAB_WIDEN
);
1206 emit_cmp_and_jump_insns (available
, size
, GEU
, NULL_RTX
, Pmode
, 1,
1210 emit_insn (gen_trap ());
1213 error ("stack limits not supported on this target");
1215 emit_label (space_available
);
1218 anti_adjust_stack (size
);
1220 #ifdef STACK_GROWS_DOWNWARD
1221 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1227 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1228 but we know it can't. So add ourselves and then do
1230 target
= expand_binop (Pmode
, add_optab
, target
,
1231 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1232 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1233 target
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, target
,
1234 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1236 target
= expand_mult (Pmode
, target
,
1237 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1241 /* Record the new stack level for nonlocal gotos. */
1242 if (cfun
->nonlocal_goto_save_area
!= 0)
1243 update_nonlocal_goto_save_area ();
1248 /* A front end may want to override GCC's stack checking by providing a
1249 run-time routine to call to check the stack, so provide a mechanism for
1250 calling that routine. */
1252 static GTY(()) rtx stack_check_libfunc
;
1255 set_stack_check_libfunc (rtx libfunc
)
1257 stack_check_libfunc
= libfunc
;
1260 /* Emit one stack probe at ADDRESS, an address within the stack. */
1263 emit_stack_probe (rtx address
)
1265 rtx memref
= gen_rtx_MEM (word_mode
, address
);
1267 MEM_VOLATILE_P (memref
) = 1;
1269 if (STACK_CHECK_PROBE_LOAD
)
1270 emit_move_insn (gen_reg_rtx (word_mode
), memref
);
1272 emit_move_insn (memref
, const0_rtx
);
1275 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1276 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1277 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1278 subtract from the stack. If SIZE is constant, this is done
1279 with a fixed number of probes. Otherwise, we must make a loop. */
1281 #ifdef STACK_GROWS_DOWNWARD
1282 #define STACK_GROW_OP MINUS
1284 #define STACK_GROW_OP PLUS
1288 probe_stack_range (HOST_WIDE_INT first
, rtx size
)
1290 /* First ensure SIZE is Pmode. */
1291 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1292 size
= convert_to_mode (Pmode
, size
, 1);
1294 /* Next see if the front end has set up a function for us to call to
1296 if (stack_check_libfunc
!= 0)
1298 rtx addr
= memory_address (QImode
,
1299 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1301 plus_constant (size
, first
)));
1303 addr
= convert_memory_address (ptr_mode
, addr
);
1304 emit_library_call (stack_check_libfunc
, LCT_NORMAL
, VOIDmode
, 1, addr
,
1308 /* Next see if we have an insn to check the stack. Use it if so. */
1309 #ifdef HAVE_check_stack
1310 else if (HAVE_check_stack
)
1312 insn_operand_predicate_fn pred
;
1314 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1316 plus_constant (size
, first
)),
1319 pred
= insn_data
[(int) CODE_FOR_check_stack
].operand
[0].predicate
;
1320 if (pred
&& ! ((*pred
) (last_addr
, Pmode
)))
1321 last_addr
= copy_to_mode_reg (Pmode
, last_addr
);
1323 emit_insn (gen_check_stack (last_addr
));
1327 /* If we have to generate explicit probes, see if we have a constant
1328 small number of them to generate. If so, that's the easy case. */
1329 else if (GET_CODE (size
) == CONST_INT
1330 && INTVAL (size
) < 10 * STACK_CHECK_PROBE_INTERVAL
)
1332 HOST_WIDE_INT offset
;
1334 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1335 for values of N from 1 until it exceeds LAST. If only one
1336 probe is needed, this will not generate any code. Then probe
1338 for (offset
= first
+ STACK_CHECK_PROBE_INTERVAL
;
1339 offset
< INTVAL (size
);
1340 offset
= offset
+ STACK_CHECK_PROBE_INTERVAL
)
1341 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1345 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1347 plus_constant (size
, first
)));
1350 /* In the variable case, do the same as above, but in a loop. We emit loop
1351 notes so that loop optimization can be done. */
1355 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1357 GEN_INT (first
+ STACK_CHECK_PROBE_INTERVAL
)),
1360 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1362 plus_constant (size
, first
)),
1364 rtx incr
= GEN_INT (STACK_CHECK_PROBE_INTERVAL
);
1365 rtx loop_lab
= gen_label_rtx ();
1366 rtx test_lab
= gen_label_rtx ();
1367 rtx end_lab
= gen_label_rtx ();
1370 if (!REG_P (test_addr
)
1371 || REGNO (test_addr
) < FIRST_PSEUDO_REGISTER
)
1372 test_addr
= force_reg (Pmode
, test_addr
);
1374 emit_jump (test_lab
);
1376 emit_label (loop_lab
);
1377 emit_stack_probe (test_addr
);
1379 #ifdef STACK_GROWS_DOWNWARD
1380 #define CMP_OPCODE GTU
1381 temp
= expand_binop (Pmode
, sub_optab
, test_addr
, incr
, test_addr
,
1384 #define CMP_OPCODE LTU
1385 temp
= expand_binop (Pmode
, add_optab
, test_addr
, incr
, test_addr
,
1389 gcc_assert (temp
== test_addr
);
1391 emit_label (test_lab
);
1392 emit_cmp_and_jump_insns (test_addr
, last_addr
, CMP_OPCODE
,
1393 NULL_RTX
, Pmode
, 1, loop_lab
);
1394 emit_jump (end_lab
);
1395 emit_label (end_lab
);
1397 emit_stack_probe (last_addr
);
1401 /* Return an rtx representing the register or memory location
1402 in which a scalar value of data type VALTYPE
1403 was returned by a function call to function FUNC.
1404 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1405 function is known, otherwise 0.
1406 OUTGOING is 1 if on a machine with register windows this function
1407 should return the register in which the function will put its result
1411 hard_function_value (tree valtype
, tree func
, tree fntype
,
1412 int outgoing ATTRIBUTE_UNUSED
)
1416 val
= targetm
.calls
.function_value (valtype
, func
? func
: fntype
, outgoing
);
1419 && GET_MODE (val
) == BLKmode
)
1421 unsigned HOST_WIDE_INT bytes
= int_size_in_bytes (valtype
);
1422 enum machine_mode tmpmode
;
1424 /* int_size_in_bytes can return -1. We don't need a check here
1425 since the value of bytes will then be large enough that no
1426 mode will match anyway. */
1428 for (tmpmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
1429 tmpmode
!= VOIDmode
;
1430 tmpmode
= GET_MODE_WIDER_MODE (tmpmode
))
1432 /* Have we found a large enough mode? */
1433 if (GET_MODE_SIZE (tmpmode
) >= bytes
)
1437 /* No suitable mode found. */
1438 gcc_assert (tmpmode
!= VOIDmode
);
1440 PUT_MODE (val
, tmpmode
);
1445 /* Return an rtx representing the register or memory location
1446 in which a scalar value of mode MODE was returned by a library call. */
1449 hard_libcall_value (enum machine_mode mode
)
1451 return LIBCALL_VALUE (mode
);
1454 /* Look up the tree code for a given rtx code
1455 to provide the arithmetic operation for REAL_ARITHMETIC.
1456 The function returns an int because the caller may not know
1457 what `enum tree_code' means. */
1460 rtx_to_tree_code (enum rtx_code code
)
1462 enum tree_code tcode
;
1485 tcode
= LAST_AND_UNUSED_TREE_CODE
;
1488 return ((int) tcode
);
1491 #include "gt-explow.h"