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, 2007
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 3, 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 COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
25 #include "coretypes.h"
35 #include "hard-reg-set.h"
36 #include "insn-config.h"
39 #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);
248 size
= lang_hooks
.expr_size (exp
);
250 size
= SUBSTITUTE_PLACEHOLDER_IN_EXPR (size
, exp
);
253 return expand_expr (size
, NULL_RTX
, TYPE_MODE (sizetype
), EXPAND_NORMAL
);
256 /* Return a wide integer for the size in bytes of the value of EXP, or -1
257 if the size can vary or is larger than an integer. */
260 int_expr_size (tree exp
)
264 if (TREE_CODE (exp
) == WITH_SIZE_EXPR
)
265 size
= TREE_OPERAND (exp
, 1);
268 size
= lang_hooks
.expr_size (exp
);
272 if (size
== 0 || !host_integerp (size
, 0))
275 return tree_low_cst (size
, 0);
278 /* Return a copy of X in which all memory references
279 and all constants that involve symbol refs
280 have been replaced with new temporary registers.
281 Also emit code to load the memory locations and constants
282 into those registers.
284 If X contains no such constants or memory references,
285 X itself (not a copy) is returned.
287 If a constant is found in the address that is not a legitimate constant
288 in an insn, it is left alone in the hope that it might be valid in the
291 X may contain no arithmetic except addition, subtraction and multiplication.
292 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
295 break_out_memory_refs (rtx x
)
298 || (CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
)
299 && GET_MODE (x
) != VOIDmode
))
300 x
= force_reg (GET_MODE (x
), x
);
301 else if (GET_CODE (x
) == PLUS
|| GET_CODE (x
) == MINUS
302 || GET_CODE (x
) == MULT
)
304 rtx op0
= break_out_memory_refs (XEXP (x
, 0));
305 rtx op1
= break_out_memory_refs (XEXP (x
, 1));
307 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
308 x
= simplify_gen_binary (GET_CODE (x
), Pmode
, op0
, op1
);
314 /* Given X, a memory address in ptr_mode, convert it to an address
315 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
316 the fact that pointers are not allowed to overflow by commuting arithmetic
317 operations over conversions so that address arithmetic insns can be
321 convert_memory_address (enum machine_mode to_mode ATTRIBUTE_UNUSED
,
324 #ifndef POINTERS_EXTEND_UNSIGNED
325 gcc_assert (GET_MODE (x
) == to_mode
|| GET_MODE (x
) == VOIDmode
);
327 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
328 enum machine_mode from_mode
;
332 /* If X already has the right mode, just return it. */
333 if (GET_MODE (x
) == to_mode
)
336 from_mode
= to_mode
== ptr_mode
? Pmode
: ptr_mode
;
338 /* Here we handle some special cases. If none of them apply, fall through
339 to the default case. */
340 switch (GET_CODE (x
))
344 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
))
346 else if (POINTERS_EXTEND_UNSIGNED
< 0)
348 else if (POINTERS_EXTEND_UNSIGNED
> 0)
352 temp
= simplify_unary_operation (code
, to_mode
, x
, from_mode
);
358 if ((SUBREG_PROMOTED_VAR_P (x
) || REG_POINTER (SUBREG_REG (x
)))
359 && GET_MODE (SUBREG_REG (x
)) == to_mode
)
360 return SUBREG_REG (x
);
364 temp
= gen_rtx_LABEL_REF (to_mode
, XEXP (x
, 0));
365 LABEL_REF_NONLOCAL_P (temp
) = LABEL_REF_NONLOCAL_P (x
);
370 temp
= shallow_copy_rtx (x
);
371 PUT_MODE (temp
, to_mode
);
376 return gen_rtx_CONST (to_mode
,
377 convert_memory_address (to_mode
, XEXP (x
, 0)));
382 /* For addition we can safely permute the conversion and addition
383 operation if one operand is a constant and converting the constant
384 does not change it or if one operand is a constant and we are
385 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
386 We can always safely permute them if we are making the address
388 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
)
389 || (GET_CODE (x
) == PLUS
390 && GET_CODE (XEXP (x
, 1)) == CONST_INT
391 && (XEXP (x
, 1) == convert_memory_address (to_mode
, XEXP (x
, 1))
392 || POINTERS_EXTEND_UNSIGNED
< 0)))
393 return gen_rtx_fmt_ee (GET_CODE (x
), to_mode
,
394 convert_memory_address (to_mode
, XEXP (x
, 0)),
402 return convert_modes (to_mode
, from_mode
,
403 x
, POINTERS_EXTEND_UNSIGNED
);
404 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
407 /* Return something equivalent to X but valid as a memory address
408 for something of mode MODE. When X is not itself valid, this
409 works by copying X or subexpressions of it into registers. */
412 memory_address (enum machine_mode mode
, rtx x
)
416 x
= convert_memory_address (Pmode
, x
);
418 /* By passing constant addresses through registers
419 we get a chance to cse them. */
420 if (! cse_not_expected
&& CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
))
421 x
= force_reg (Pmode
, x
);
423 /* We get better cse by rejecting indirect addressing at this stage.
424 Let the combiner create indirect addresses where appropriate.
425 For now, generate the code so that the subexpressions useful to share
426 are visible. But not if cse won't be done! */
429 if (! cse_not_expected
&& !REG_P (x
))
430 x
= break_out_memory_refs (x
);
432 /* At this point, any valid address is accepted. */
433 if (memory_address_p (mode
, x
))
436 /* If it was valid before but breaking out memory refs invalidated it,
437 use it the old way. */
438 if (memory_address_p (mode
, oldx
))
444 /* Perform machine-dependent transformations on X
445 in certain cases. This is not necessary since the code
446 below can handle all possible cases, but machine-dependent
447 transformations can make better code. */
448 LEGITIMIZE_ADDRESS (x
, oldx
, mode
, done
);
450 /* PLUS and MULT can appear in special ways
451 as the result of attempts to make an address usable for indexing.
452 Usually they are dealt with by calling force_operand, below.
453 But a sum containing constant terms is special
454 if removing them makes the sum a valid address:
455 then we generate that address in a register
456 and index off of it. We do this because it often makes
457 shorter code, and because the addresses thus generated
458 in registers often become common subexpressions. */
459 if (GET_CODE (x
) == PLUS
)
461 rtx constant_term
= const0_rtx
;
462 rtx y
= eliminate_constant_term (x
, &constant_term
);
463 if (constant_term
== const0_rtx
464 || ! memory_address_p (mode
, y
))
465 x
= force_operand (x
, NULL_RTX
);
468 y
= gen_rtx_PLUS (GET_MODE (x
), copy_to_reg (y
), constant_term
);
469 if (! memory_address_p (mode
, y
))
470 x
= force_operand (x
, NULL_RTX
);
476 else if (GET_CODE (x
) == MULT
|| GET_CODE (x
) == MINUS
)
477 x
= force_operand (x
, NULL_RTX
);
479 /* If we have a register that's an invalid address,
480 it must be a hard reg of the wrong class. Copy it to a pseudo. */
484 /* Last resort: copy the value to a register, since
485 the register is a valid address. */
487 x
= force_reg (Pmode
, x
);
492 gcc_assert (memory_address_p (mode
, x
));
493 /* If we didn't change the address, we are done. Otherwise, mark
494 a reg as a pointer if we have REG or REG + CONST_INT. */
498 mark_reg_pointer (x
, BITS_PER_UNIT
);
499 else if (GET_CODE (x
) == PLUS
500 && REG_P (XEXP (x
, 0))
501 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
502 mark_reg_pointer (XEXP (x
, 0), BITS_PER_UNIT
);
504 /* OLDX may have been the address on a temporary. Update the address
505 to indicate that X is now used. */
506 update_temp_slot_address (oldx
, x
);
511 /* Convert a mem ref into one with a valid memory address.
512 Pass through anything else unchanged. */
515 validize_mem (rtx ref
)
519 ref
= use_anchored_address (ref
);
520 if (memory_address_p (GET_MODE (ref
), XEXP (ref
, 0)))
523 /* Don't alter REF itself, since that is probably a stack slot. */
524 return replace_equiv_address (ref
, XEXP (ref
, 0));
527 /* If X is a memory reference to a member of an object block, try rewriting
528 it to use an anchor instead. Return the new memory reference on success
529 and the old one on failure. */
532 use_anchored_address (rtx x
)
535 HOST_WIDE_INT offset
;
537 if (!flag_section_anchors
)
543 /* Split the address into a base and offset. */
546 if (GET_CODE (base
) == CONST
547 && GET_CODE (XEXP (base
, 0)) == PLUS
548 && GET_CODE (XEXP (XEXP (base
, 0), 1)) == CONST_INT
)
550 offset
+= INTVAL (XEXP (XEXP (base
, 0), 1));
551 base
= XEXP (XEXP (base
, 0), 0);
554 /* Check whether BASE is suitable for anchors. */
555 if (GET_CODE (base
) != SYMBOL_REF
556 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base
)
557 || SYMBOL_REF_ANCHOR_P (base
)
558 || SYMBOL_REF_BLOCK (base
) == NULL
559 || !targetm
.use_anchors_for_symbol_p (base
))
562 /* Decide where BASE is going to be. */
563 place_block_symbol (base
);
565 /* Get the anchor we need to use. */
566 offset
+= SYMBOL_REF_BLOCK_OFFSET (base
);
567 base
= get_section_anchor (SYMBOL_REF_BLOCK (base
), offset
,
568 SYMBOL_REF_TLS_MODEL (base
));
570 /* Work out the offset from the anchor. */
571 offset
-= SYMBOL_REF_BLOCK_OFFSET (base
);
573 /* If we're going to run a CSE pass, force the anchor into a register.
574 We will then be able to reuse registers for several accesses, if the
575 target costs say that that's worthwhile. */
576 if (!cse_not_expected
)
577 base
= force_reg (GET_MODE (base
), base
);
579 return replace_equiv_address (x
, plus_constant (base
, offset
));
582 /* Copy the value or contents of X to a new temp reg and return that reg. */
587 rtx temp
= gen_reg_rtx (GET_MODE (x
));
589 /* If not an operand, must be an address with PLUS and MULT so
590 do the computation. */
591 if (! general_operand (x
, VOIDmode
))
592 x
= force_operand (x
, temp
);
595 emit_move_insn (temp
, x
);
600 /* Like copy_to_reg but always give the new register mode Pmode
601 in case X is a constant. */
604 copy_addr_to_reg (rtx x
)
606 return copy_to_mode_reg (Pmode
, x
);
609 /* Like copy_to_reg but always give the new register mode MODE
610 in case X is a constant. */
613 copy_to_mode_reg (enum machine_mode mode
, rtx x
)
615 rtx temp
= gen_reg_rtx (mode
);
617 /* If not an operand, must be an address with PLUS and MULT so
618 do the computation. */
619 if (! general_operand (x
, VOIDmode
))
620 x
= force_operand (x
, temp
);
622 gcc_assert (GET_MODE (x
) == mode
|| GET_MODE (x
) == VOIDmode
);
624 emit_move_insn (temp
, x
);
628 /* Load X into a register if it is not already one.
629 Use mode MODE for the register.
630 X should be valid for mode MODE, but it may be a constant which
631 is valid for all integer modes; that's why caller must specify MODE.
633 The caller must not alter the value in the register we return,
634 since we mark it as a "constant" register. */
637 force_reg (enum machine_mode mode
, rtx x
)
644 if (general_operand (x
, mode
))
646 temp
= gen_reg_rtx (mode
);
647 insn
= emit_move_insn (temp
, x
);
651 temp
= force_operand (x
, NULL_RTX
);
653 insn
= get_last_insn ();
656 rtx temp2
= gen_reg_rtx (mode
);
657 insn
= emit_move_insn (temp2
, temp
);
662 /* Let optimizers know that TEMP's value never changes
663 and that X can be substituted for it. Don't get confused
664 if INSN set something else (such as a SUBREG of TEMP). */
666 && (set
= single_set (insn
)) != 0
667 && SET_DEST (set
) == temp
668 && ! rtx_equal_p (x
, SET_SRC (set
)))
669 set_unique_reg_note (insn
, REG_EQUAL
, x
);
671 /* Let optimizers know that TEMP is a pointer, and if so, the
672 known alignment of that pointer. */
675 if (GET_CODE (x
) == SYMBOL_REF
)
677 align
= BITS_PER_UNIT
;
678 if (SYMBOL_REF_DECL (x
) && DECL_P (SYMBOL_REF_DECL (x
)))
679 align
= DECL_ALIGN (SYMBOL_REF_DECL (x
));
681 else if (GET_CODE (x
) == LABEL_REF
)
682 align
= BITS_PER_UNIT
;
683 else if (GET_CODE (x
) == CONST
684 && GET_CODE (XEXP (x
, 0)) == PLUS
685 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == SYMBOL_REF
686 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
)
688 rtx s
= XEXP (XEXP (x
, 0), 0);
689 rtx c
= XEXP (XEXP (x
, 0), 1);
693 if (SYMBOL_REF_DECL (s
) && DECL_P (SYMBOL_REF_DECL (s
)))
694 sa
= DECL_ALIGN (SYMBOL_REF_DECL (s
));
696 ca
= exact_log2 (INTVAL (c
) & -INTVAL (c
)) * BITS_PER_UNIT
;
698 align
= MIN (sa
, ca
);
700 else if (MEM_P (x
) && MEM_POINTER (x
))
701 align
= MEM_ALIGN (x
);
704 mark_reg_pointer (temp
, align
);
710 /* If X is a memory ref, copy its contents to a new temp reg and return
711 that reg. Otherwise, return X. */
714 force_not_mem (rtx x
)
718 if (!MEM_P (x
) || GET_MODE (x
) == BLKmode
)
721 temp
= gen_reg_rtx (GET_MODE (x
));
724 REG_POINTER (temp
) = 1;
726 emit_move_insn (temp
, x
);
730 /* Copy X to TARGET (if it's nonzero and a reg)
731 or to a new temp reg and return that reg.
732 MODE is the mode to use for X in case it is a constant. */
735 copy_to_suggested_reg (rtx x
, rtx target
, enum machine_mode mode
)
739 if (target
&& REG_P (target
))
742 temp
= gen_reg_rtx (mode
);
744 emit_move_insn (temp
, x
);
748 /* Return the mode to use to store a scalar of TYPE and MODE.
749 PUNSIGNEDP points to the signedness of the type and may be adjusted
750 to show what signedness to use on extension operations.
752 FOR_CALL is nonzero if this call is promoting args for a call. */
754 #if defined(PROMOTE_MODE) && !defined(PROMOTE_FUNCTION_MODE)
755 #define PROMOTE_FUNCTION_MODE PROMOTE_MODE
759 promote_mode (const_tree type
, enum machine_mode mode
, int *punsignedp
,
760 int for_call ATTRIBUTE_UNUSED
)
762 const enum tree_code code
= TREE_CODE (type
);
763 int unsignedp
= *punsignedp
;
772 #ifdef PROMOTE_FUNCTION_MODE
773 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
774 case REAL_TYPE
: case OFFSET_TYPE
: case FIXED_POINT_TYPE
:
779 PROMOTE_FUNCTION_MODE (mode
, unsignedp
, type
);
784 PROMOTE_MODE (mode
, unsignedp
, type
);
790 #ifdef POINTERS_EXTEND_UNSIGNED
794 unsignedp
= POINTERS_EXTEND_UNSIGNED
;
802 *punsignedp
= unsignedp
;
806 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
807 This pops when ADJUST is positive. ADJUST need not be constant. */
810 adjust_stack (rtx adjust
)
814 if (adjust
== const0_rtx
)
817 /* We expect all variable sized adjustments to be multiple of
818 PREFERRED_STACK_BOUNDARY. */
819 if (GET_CODE (adjust
) == CONST_INT
)
820 stack_pointer_delta
-= INTVAL (adjust
);
822 temp
= expand_binop (Pmode
,
823 #ifdef STACK_GROWS_DOWNWARD
828 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
831 if (temp
!= stack_pointer_rtx
)
832 emit_move_insn (stack_pointer_rtx
, temp
);
835 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
836 This pushes when ADJUST is positive. ADJUST need not be constant. */
839 anti_adjust_stack (rtx adjust
)
843 if (adjust
== const0_rtx
)
846 /* We expect all variable sized adjustments to be multiple of
847 PREFERRED_STACK_BOUNDARY. */
848 if (GET_CODE (adjust
) == CONST_INT
)
849 stack_pointer_delta
+= INTVAL (adjust
);
851 temp
= expand_binop (Pmode
,
852 #ifdef STACK_GROWS_DOWNWARD
857 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
860 if (temp
!= stack_pointer_rtx
)
861 emit_move_insn (stack_pointer_rtx
, temp
);
864 /* Round the size of a block to be pushed up to the boundary required
865 by this machine. SIZE is the desired size, which need not be constant. */
868 round_push (rtx size
)
870 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
875 if (GET_CODE (size
) == CONST_INT
)
877 HOST_WIDE_INT
new = (INTVAL (size
) + align
- 1) / align
* align
;
879 if (INTVAL (size
) != new)
880 size
= GEN_INT (new);
884 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
885 but we know it can't. So add ourselves and then do
887 size
= expand_binop (Pmode
, add_optab
, size
, GEN_INT (align
- 1),
888 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
889 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
, GEN_INT (align
),
891 size
= expand_mult (Pmode
, size
, GEN_INT (align
), NULL_RTX
, 1);
897 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
898 to a previously-created save area. If no save area has been allocated,
899 this function will allocate one. If a save area is specified, it
900 must be of the proper mode.
902 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
903 are emitted at the current position. */
906 emit_stack_save (enum save_level save_level
, rtx
*psave
, rtx after
)
909 /* The default is that we use a move insn and save in a Pmode object. */
910 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
911 enum machine_mode mode
= STACK_SAVEAREA_MODE (save_level
);
913 /* See if this machine has anything special to do for this kind of save. */
916 #ifdef HAVE_save_stack_block
918 if (HAVE_save_stack_block
)
919 fcn
= gen_save_stack_block
;
922 #ifdef HAVE_save_stack_function
924 if (HAVE_save_stack_function
)
925 fcn
= gen_save_stack_function
;
928 #ifdef HAVE_save_stack_nonlocal
930 if (HAVE_save_stack_nonlocal
)
931 fcn
= gen_save_stack_nonlocal
;
938 /* If there is no save area and we have to allocate one, do so. Otherwise
939 verify the save area is the proper mode. */
943 if (mode
!= VOIDmode
)
945 if (save_level
== SAVE_NONLOCAL
)
946 *psave
= sa
= assign_stack_local (mode
, GET_MODE_SIZE (mode
), 0);
948 *psave
= sa
= gen_reg_rtx (mode
);
957 do_pending_stack_adjust ();
958 /* We must validize inside the sequence, to ensure that any instructions
959 created by the validize call also get moved to the right place. */
961 sa
= validize_mem (sa
);
962 emit_insn (fcn (sa
, stack_pointer_rtx
));
965 emit_insn_after (seq
, after
);
969 do_pending_stack_adjust ();
971 sa
= validize_mem (sa
);
972 emit_insn (fcn (sa
, stack_pointer_rtx
));
976 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
977 area made by emit_stack_save. If it is zero, we have nothing to do.
979 Put any emitted insns after insn AFTER, if nonzero, otherwise at
983 emit_stack_restore (enum save_level save_level
, rtx sa
, rtx after
)
985 /* The default is that we use a move insn. */
986 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
988 /* See if this machine has anything special to do for this kind of save. */
991 #ifdef HAVE_restore_stack_block
993 if (HAVE_restore_stack_block
)
994 fcn
= gen_restore_stack_block
;
997 #ifdef HAVE_restore_stack_function
999 if (HAVE_restore_stack_function
)
1000 fcn
= gen_restore_stack_function
;
1003 #ifdef HAVE_restore_stack_nonlocal
1005 if (HAVE_restore_stack_nonlocal
)
1006 fcn
= gen_restore_stack_nonlocal
;
1015 sa
= validize_mem (sa
);
1016 /* These clobbers prevent the scheduler from moving
1017 references to variable arrays below the code
1018 that deletes (pops) the arrays. */
1019 emit_insn (gen_rtx_CLOBBER (VOIDmode
,
1020 gen_rtx_MEM (BLKmode
,
1021 gen_rtx_SCRATCH (VOIDmode
))));
1022 emit_insn (gen_rtx_CLOBBER (VOIDmode
,
1023 gen_rtx_MEM (BLKmode
, stack_pointer_rtx
)));
1026 discard_pending_stack_adjust ();
1033 emit_insn (fcn (stack_pointer_rtx
, sa
));
1036 emit_insn_after (seq
, after
);
1039 emit_insn (fcn (stack_pointer_rtx
, sa
));
1042 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1043 function. This function should be called whenever we allocate or
1044 deallocate dynamic stack space. */
1047 update_nonlocal_goto_save_area (void)
1052 /* The nonlocal_goto_save_area object is an array of N pointers. The
1053 first one is used for the frame pointer save; the rest are sized by
1054 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1055 of the stack save area slots. */
1056 t_save
= build4 (ARRAY_REF
, ptr_type_node
, cfun
->nonlocal_goto_save_area
,
1057 integer_one_node
, NULL_TREE
, NULL_TREE
);
1058 r_save
= expand_expr (t_save
, NULL_RTX
, VOIDmode
, EXPAND_WRITE
);
1060 emit_stack_save (SAVE_NONLOCAL
, &r_save
, NULL_RTX
);
1063 /* Return an rtx representing the address of an area of memory dynamically
1064 pushed on the stack. This region of memory is always aligned to
1065 a multiple of BIGGEST_ALIGNMENT.
1067 Any required stack pointer alignment is preserved.
1069 SIZE is an rtx representing the size of the area.
1070 TARGET is a place in which the address can be placed.
1072 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1075 allocate_dynamic_stack_space (rtx size
, rtx target
, int known_align
)
1077 /* If we're asking for zero bytes, it doesn't matter what we point
1078 to since we can't dereference it. But return a reasonable
1080 if (size
== const0_rtx
)
1081 return virtual_stack_dynamic_rtx
;
1083 /* Otherwise, show we're calling alloca or equivalent. */
1084 cfun
->calls_alloca
= 1;
1086 /* Ensure the size is in the proper mode. */
1087 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1088 size
= convert_to_mode (Pmode
, size
, 1);
1090 /* We can't attempt to minimize alignment necessary, because we don't
1091 know the final value of preferred_stack_boundary yet while executing
1093 crtl
->preferred_stack_boundary
= PREFERRED_STACK_BOUNDARY
;
1095 /* We will need to ensure that the address we return is aligned to
1096 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1097 always know its final value at this point in the compilation (it
1098 might depend on the size of the outgoing parameter lists, for
1099 example), so we must align the value to be returned in that case.
1100 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1101 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1102 We must also do an alignment operation on the returned value if
1103 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1105 If we have to align, we must leave space in SIZE for the hole
1106 that might result from the alignment operation. */
1108 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1109 #define MUST_ALIGN 1
1111 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1116 = force_operand (plus_constant (size
,
1117 BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1120 #ifdef SETJMP_VIA_SAVE_AREA
1121 /* If setjmp restores regs from a save area in the stack frame,
1122 avoid clobbering the reg save area. Note that the offset of
1123 virtual_incoming_args_rtx includes the preallocated stack args space.
1124 It would be no problem to clobber that, but it's on the wrong side
1125 of the old save area.
1127 What used to happen is that, since we did not know for sure
1128 whether setjmp() was invoked until after RTL generation, we
1129 would use reg notes to store the "optimized" size and fix things
1130 up later. These days we know this information before we ever
1131 start building RTL so the reg notes are unnecessary. */
1132 if (!cfun
->calls_setjmp
)
1134 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
1136 /* ??? Code below assumes that the save area needs maximal
1137 alignment. This constraint may be too strong. */
1138 gcc_assert (PREFERRED_STACK_BOUNDARY
== BIGGEST_ALIGNMENT
);
1140 if (GET_CODE (size
) == CONST_INT
)
1142 HOST_WIDE_INT
new = INTVAL (size
) / align
* align
;
1144 if (INTVAL (size
) != new)
1145 size
= GEN_INT (new);
1149 /* Since we know overflow is not possible, we avoid using
1150 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1151 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
,
1152 GEN_INT (align
), NULL_RTX
, 1);
1153 size
= expand_mult (Pmode
, size
,
1154 GEN_INT (align
), NULL_RTX
, 1);
1160 = expand_binop (Pmode
, sub_optab
, virtual_stack_dynamic_rtx
,
1161 stack_pointer_rtx
, NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1163 size
= expand_binop (Pmode
, add_optab
, size
, dynamic_offset
,
1164 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1166 #endif /* SETJMP_VIA_SAVE_AREA */
1168 /* Round the size to a multiple of the required stack alignment.
1169 Since the stack if presumed to be rounded before this allocation,
1170 this will maintain the required alignment.
1172 If the stack grows downward, we could save an insn by subtracting
1173 SIZE from the stack pointer and then aligning the stack pointer.
1174 The problem with this is that the stack pointer may be unaligned
1175 between the execution of the subtraction and alignment insns and
1176 some machines do not allow this. Even on those that do, some
1177 signal handlers malfunction if a signal should occur between those
1178 insns. Since this is an extremely rare event, we have no reliable
1179 way of knowing which systems have this problem. So we avoid even
1180 momentarily mis-aligning the stack. */
1182 /* If we added a variable amount to SIZE,
1183 we can no longer assume it is aligned. */
1184 #if !defined (SETJMP_VIA_SAVE_AREA)
1185 if (MUST_ALIGN
|| known_align
% PREFERRED_STACK_BOUNDARY
!= 0)
1187 size
= round_push (size
);
1189 do_pending_stack_adjust ();
1191 /* We ought to be called always on the toplevel and stack ought to be aligned
1193 gcc_assert (!(stack_pointer_delta
1194 % (PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
)));
1196 /* If needed, check that we have the required amount of stack. Take into
1197 account what has already been checked. */
1198 if (flag_stack_check
&& ! STACK_CHECK_BUILTIN
)
1199 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE
+ STACK_CHECK_PROTECT
, size
);
1201 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1202 if (target
== 0 || !REG_P (target
)
1203 || REGNO (target
) < FIRST_PSEUDO_REGISTER
1204 || GET_MODE (target
) != Pmode
)
1205 target
= gen_reg_rtx (Pmode
);
1207 mark_reg_pointer (target
, known_align
);
1209 /* Perform the required allocation from the stack. Some systems do
1210 this differently than simply incrementing/decrementing from the
1211 stack pointer, such as acquiring the space by calling malloc(). */
1212 #ifdef HAVE_allocate_stack
1213 if (HAVE_allocate_stack
)
1215 enum machine_mode mode
= STACK_SIZE_MODE
;
1216 insn_operand_predicate_fn pred
;
1218 /* We don't have to check against the predicate for operand 0 since
1219 TARGET is known to be a pseudo of the proper mode, which must
1220 be valid for the operand. For operand 1, convert to the
1221 proper mode and validate. */
1222 if (mode
== VOIDmode
)
1223 mode
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].mode
;
1225 pred
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].predicate
;
1226 if (pred
&& ! ((*pred
) (size
, mode
)))
1227 size
= copy_to_mode_reg (mode
, convert_to_mode (mode
, size
, 1));
1229 emit_insn (gen_allocate_stack (target
, size
));
1234 #ifndef STACK_GROWS_DOWNWARD
1235 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1238 /* Check stack bounds if necessary. */
1239 if (crtl
->limit_stack
)
1242 rtx space_available
= gen_label_rtx ();
1243 #ifdef STACK_GROWS_DOWNWARD
1244 available
= expand_binop (Pmode
, sub_optab
,
1245 stack_pointer_rtx
, stack_limit_rtx
,
1246 NULL_RTX
, 1, OPTAB_WIDEN
);
1248 available
= expand_binop (Pmode
, sub_optab
,
1249 stack_limit_rtx
, stack_pointer_rtx
,
1250 NULL_RTX
, 1, OPTAB_WIDEN
);
1252 emit_cmp_and_jump_insns (available
, size
, GEU
, NULL_RTX
, Pmode
, 1,
1256 emit_insn (gen_trap ());
1259 error ("stack limits not supported on this target");
1261 emit_label (space_available
);
1264 anti_adjust_stack (size
);
1266 #ifdef STACK_GROWS_DOWNWARD
1267 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1273 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1274 but we know it can't. So add ourselves and then do
1276 target
= expand_binop (Pmode
, add_optab
, target
,
1277 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1278 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1279 target
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, target
,
1280 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1282 target
= expand_mult (Pmode
, target
,
1283 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1287 /* Record the new stack level for nonlocal gotos. */
1288 if (cfun
->nonlocal_goto_save_area
!= 0)
1289 update_nonlocal_goto_save_area ();
1294 /* A front end may want to override GCC's stack checking by providing a
1295 run-time routine to call to check the stack, so provide a mechanism for
1296 calling that routine. */
1298 static GTY(()) rtx stack_check_libfunc
;
1301 set_stack_check_libfunc (rtx libfunc
)
1303 stack_check_libfunc
= libfunc
;
1306 /* Emit one stack probe at ADDRESS, an address within the stack. */
1309 emit_stack_probe (rtx address
)
1311 rtx memref
= gen_rtx_MEM (word_mode
, address
);
1313 MEM_VOLATILE_P (memref
) = 1;
1315 if (STACK_CHECK_PROBE_LOAD
)
1316 emit_move_insn (gen_reg_rtx (word_mode
), memref
);
1318 emit_move_insn (memref
, const0_rtx
);
1321 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1322 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1323 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1324 subtract from the stack. If SIZE is constant, this is done
1325 with a fixed number of probes. Otherwise, we must make a loop. */
1327 #ifdef STACK_GROWS_DOWNWARD
1328 #define STACK_GROW_OP MINUS
1330 #define STACK_GROW_OP PLUS
1334 probe_stack_range (HOST_WIDE_INT first
, rtx size
)
1336 /* First ensure SIZE is Pmode. */
1337 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1338 size
= convert_to_mode (Pmode
, size
, 1);
1340 /* Next see if the front end has set up a function for us to call to
1342 if (stack_check_libfunc
!= 0)
1344 rtx addr
= memory_address (QImode
,
1345 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1347 plus_constant (size
, first
)));
1349 addr
= convert_memory_address (ptr_mode
, addr
);
1350 emit_library_call (stack_check_libfunc
, LCT_NORMAL
, VOIDmode
, 1, addr
,
1354 /* Next see if we have an insn to check the stack. Use it if so. */
1355 #ifdef HAVE_check_stack
1356 else if (HAVE_check_stack
)
1358 insn_operand_predicate_fn pred
;
1360 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1362 plus_constant (size
, first
)),
1365 pred
= insn_data
[(int) CODE_FOR_check_stack
].operand
[0].predicate
;
1366 if (pred
&& ! ((*pred
) (last_addr
, Pmode
)))
1367 last_addr
= copy_to_mode_reg (Pmode
, last_addr
);
1369 emit_insn (gen_check_stack (last_addr
));
1373 /* If we have to generate explicit probes, see if we have a constant
1374 small number of them to generate. If so, that's the easy case. */
1375 else if (GET_CODE (size
) == CONST_INT
1376 && INTVAL (size
) < 10 * STACK_CHECK_PROBE_INTERVAL
)
1378 HOST_WIDE_INT offset
;
1380 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1381 for values of N from 1 until it exceeds LAST. If only one
1382 probe is needed, this will not generate any code. Then probe
1384 for (offset
= first
+ STACK_CHECK_PROBE_INTERVAL
;
1385 offset
< INTVAL (size
);
1386 offset
= offset
+ STACK_CHECK_PROBE_INTERVAL
)
1387 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1391 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1393 plus_constant (size
, first
)));
1396 /* In the variable case, do the same as above, but in a loop. We emit loop
1397 notes so that loop optimization can be done. */
1401 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1403 GEN_INT (first
+ STACK_CHECK_PROBE_INTERVAL
)),
1406 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1408 plus_constant (size
, first
)),
1410 rtx incr
= GEN_INT (STACK_CHECK_PROBE_INTERVAL
);
1411 rtx loop_lab
= gen_label_rtx ();
1412 rtx test_lab
= gen_label_rtx ();
1413 rtx end_lab
= gen_label_rtx ();
1416 if (!REG_P (test_addr
)
1417 || REGNO (test_addr
) < FIRST_PSEUDO_REGISTER
)
1418 test_addr
= force_reg (Pmode
, test_addr
);
1420 emit_jump (test_lab
);
1422 emit_label (loop_lab
);
1423 emit_stack_probe (test_addr
);
1425 #ifdef STACK_GROWS_DOWNWARD
1426 #define CMP_OPCODE GTU
1427 temp
= expand_binop (Pmode
, sub_optab
, test_addr
, incr
, test_addr
,
1430 #define CMP_OPCODE LTU
1431 temp
= expand_binop (Pmode
, add_optab
, test_addr
, incr
, test_addr
,
1435 gcc_assert (temp
== test_addr
);
1437 emit_label (test_lab
);
1438 emit_cmp_and_jump_insns (test_addr
, last_addr
, CMP_OPCODE
,
1439 NULL_RTX
, Pmode
, 1, loop_lab
);
1440 emit_jump (end_lab
);
1441 emit_label (end_lab
);
1443 emit_stack_probe (last_addr
);
1447 /* Return an rtx representing the register or memory location
1448 in which a scalar value of data type VALTYPE
1449 was returned by a function call to function FUNC.
1450 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1451 function is known, otherwise 0.
1452 OUTGOING is 1 if on a machine with register windows this function
1453 should return the register in which the function will put its result
1457 hard_function_value (const_tree valtype
, const_tree func
, const_tree fntype
,
1458 int outgoing ATTRIBUTE_UNUSED
)
1462 val
= targetm
.calls
.function_value (valtype
, func
? func
: fntype
, outgoing
);
1465 && GET_MODE (val
) == BLKmode
)
1467 unsigned HOST_WIDE_INT bytes
= int_size_in_bytes (valtype
);
1468 enum machine_mode tmpmode
;
1470 /* int_size_in_bytes can return -1. We don't need a check here
1471 since the value of bytes will then be large enough that no
1472 mode will match anyway. */
1474 for (tmpmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
1475 tmpmode
!= VOIDmode
;
1476 tmpmode
= GET_MODE_WIDER_MODE (tmpmode
))
1478 /* Have we found a large enough mode? */
1479 if (GET_MODE_SIZE (tmpmode
) >= bytes
)
1483 /* No suitable mode found. */
1484 gcc_assert (tmpmode
!= VOIDmode
);
1486 PUT_MODE (val
, tmpmode
);
1491 /* Return an rtx representing the register or memory location
1492 in which a scalar value of mode MODE was returned by a library call. */
1495 hard_libcall_value (enum machine_mode mode
)
1497 return LIBCALL_VALUE (mode
);
1500 /* Look up the tree code for a given rtx code
1501 to provide the arithmetic operation for REAL_ARITHMETIC.
1502 The function returns an int because the caller may not know
1503 what `enum tree_code' means. */
1506 rtx_to_tree_code (enum rtx_code code
)
1508 enum tree_code tcode
;
1531 tcode
= LAST_AND_UNUSED_TREE_CODE
;
1534 return ((int) tcode
);
1537 #include "gt-explow.h"