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"
44 static rtx
break_out_memory_refs (rtx
);
45 static void emit_stack_probe (rtx
);
48 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
51 trunc_int_for_mode (HOST_WIDE_INT c
, enum machine_mode mode
)
53 int width
= GET_MODE_BITSIZE (mode
);
55 /* You want to truncate to a _what_? */
56 gcc_assert (SCALAR_INT_MODE_P (mode
));
58 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
60 return c
& 1 ? STORE_FLAG_VALUE
: 0;
62 /* Sign-extend for the requested mode. */
64 if (width
< HOST_BITS_PER_WIDE_INT
)
66 HOST_WIDE_INT sign
= 1;
76 /* Return an rtx for the sum of X and the integer C. */
79 plus_constant (rtx x
, HOST_WIDE_INT c
)
83 enum machine_mode mode
;
99 return GEN_INT (INTVAL (x
) + c
);
103 unsigned HOST_WIDE_INT l1
= CONST_DOUBLE_LOW (x
);
104 HOST_WIDE_INT h1
= CONST_DOUBLE_HIGH (x
);
105 unsigned HOST_WIDE_INT l2
= c
;
106 HOST_WIDE_INT h2
= c
< 0 ? ~0 : 0;
107 unsigned HOST_WIDE_INT lv
;
110 add_double (l1
, h1
, l2
, h2
, &lv
, &hv
);
112 return immed_double_const (lv
, hv
, VOIDmode
);
116 /* If this is a reference to the constant pool, try replacing it with
117 a reference to a new constant. If the resulting address isn't
118 valid, don't return it because we have no way to validize it. */
119 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
120 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
123 = force_const_mem (GET_MODE (x
),
124 plus_constant (get_pool_constant (XEXP (x
, 0)),
126 if (memory_address_p (GET_MODE (tem
), XEXP (tem
, 0)))
132 /* If adding to something entirely constant, set a flag
133 so that we can add a CONST around the result. */
144 /* The interesting case is adding the integer to a sum.
145 Look for constant term in the sum and combine
146 with C. For an integer constant term, we make a combined
147 integer. For a constant term that is not an explicit integer,
148 we cannot really combine, but group them together anyway.
150 Restart or use a recursive call in case the remaining operand is
151 something that we handle specially, such as a SYMBOL_REF.
153 We may not immediately return from the recursive call here, lest
154 all_constant gets lost. */
156 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
)
158 c
+= INTVAL (XEXP (x
, 1));
160 if (GET_MODE (x
) != VOIDmode
)
161 c
= trunc_int_for_mode (c
, GET_MODE (x
));
166 else if (CONSTANT_P (XEXP (x
, 1)))
168 x
= gen_rtx_PLUS (mode
, XEXP (x
, 0), plus_constant (XEXP (x
, 1), c
));
171 else if (find_constant_term_loc (&y
))
173 /* We need to be careful since X may be shared and we can't
174 modify it in place. */
175 rtx copy
= copy_rtx (x
);
176 rtx
*const_loc
= find_constant_term_loc (©
);
178 *const_loc
= plus_constant (*const_loc
, c
);
189 x
= gen_rtx_PLUS (mode
, x
, GEN_INT (c
));
191 if (GET_CODE (x
) == SYMBOL_REF
|| GET_CODE (x
) == LABEL_REF
)
193 else if (all_constant
)
194 return gen_rtx_CONST (mode
, x
);
199 /* If X is a sum, return a new sum like X but lacking any constant terms.
200 Add all the removed constant terms into *CONSTPTR.
201 X itself is not altered. The result != X if and only if
202 it is not isomorphic to X. */
205 eliminate_constant_term (rtx x
, rtx
*constptr
)
210 if (GET_CODE (x
) != PLUS
)
213 /* First handle constants appearing at this level explicitly. */
214 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
215 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
), *constptr
,
217 && GET_CODE (tem
) == CONST_INT
)
220 return eliminate_constant_term (XEXP (x
, 0), constptr
);
224 x0
= eliminate_constant_term (XEXP (x
, 0), &tem
);
225 x1
= eliminate_constant_term (XEXP (x
, 1), &tem
);
226 if ((x1
!= XEXP (x
, 1) || x0
!= XEXP (x
, 0))
227 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
),
229 && GET_CODE (tem
) == CONST_INT
)
232 return gen_rtx_PLUS (GET_MODE (x
), x0
, x1
);
238 /* Return an rtx for the size in bytes of the value of EXP. */
245 if (TREE_CODE (exp
) == WITH_SIZE_EXPR
)
246 size
= TREE_OPERAND (exp
, 1);
249 size
= lang_hooks
.expr_size (exp
);
251 size
= SUBSTITUTE_PLACEHOLDER_IN_EXPR (size
, exp
);
254 return expand_expr (size
, NULL_RTX
, TYPE_MODE (sizetype
), EXPAND_NORMAL
);
257 /* Return a wide integer for the size in bytes of the value of EXP, or -1
258 if the size can vary or is larger than an integer. */
261 int_expr_size (tree exp
)
265 if (TREE_CODE (exp
) == WITH_SIZE_EXPR
)
266 size
= TREE_OPERAND (exp
, 1);
269 size
= lang_hooks
.expr_size (exp
);
273 if (size
== 0 || !host_integerp (size
, 0))
276 return tree_low_cst (size
, 0);
279 /* Return a copy of X in which all memory references
280 and all constants that involve symbol refs
281 have been replaced with new temporary registers.
282 Also emit code to load the memory locations and constants
283 into those registers.
285 If X contains no such constants or memory references,
286 X itself (not a copy) is returned.
288 If a constant is found in the address that is not a legitimate constant
289 in an insn, it is left alone in the hope that it might be valid in the
292 X may contain no arithmetic except addition, subtraction and multiplication.
293 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
296 break_out_memory_refs (rtx x
)
299 || (CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
)
300 && GET_MODE (x
) != VOIDmode
))
301 x
= force_reg (GET_MODE (x
), x
);
302 else if (GET_CODE (x
) == PLUS
|| GET_CODE (x
) == MINUS
303 || GET_CODE (x
) == MULT
)
305 rtx op0
= break_out_memory_refs (XEXP (x
, 0));
306 rtx op1
= break_out_memory_refs (XEXP (x
, 1));
308 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
309 x
= gen_rtx_fmt_ee (GET_CODE (x
), Pmode
, op0
, op1
);
315 /* Given X, a memory address in ptr_mode, convert it to an address
316 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
317 the fact that pointers are not allowed to overflow by commuting arithmetic
318 operations over conversions so that address arithmetic insns can be
322 convert_memory_address (enum machine_mode to_mode ATTRIBUTE_UNUSED
,
325 #ifndef POINTERS_EXTEND_UNSIGNED
326 gcc_assert (GET_MODE (x
) == to_mode
|| GET_MODE (x
) == VOIDmode
);
328 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
329 enum machine_mode from_mode
;
333 /* If X already has the right mode, just return it. */
334 if (GET_MODE (x
) == to_mode
)
337 from_mode
= to_mode
== ptr_mode
? Pmode
: ptr_mode
;
339 /* Here we handle some special cases. If none of them apply, fall through
340 to the default case. */
341 switch (GET_CODE (x
))
345 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
))
347 else if (POINTERS_EXTEND_UNSIGNED
< 0)
349 else if (POINTERS_EXTEND_UNSIGNED
> 0)
353 temp
= simplify_unary_operation (code
, to_mode
, x
, from_mode
);
359 if ((SUBREG_PROMOTED_VAR_P (x
) || REG_POINTER (SUBREG_REG (x
)))
360 && GET_MODE (SUBREG_REG (x
)) == to_mode
)
361 return SUBREG_REG (x
);
365 temp
= gen_rtx_LABEL_REF (to_mode
, XEXP (x
, 0));
366 LABEL_REF_NONLOCAL_P (temp
) = LABEL_REF_NONLOCAL_P (x
);
371 temp
= shallow_copy_rtx (x
);
372 PUT_MODE (temp
, to_mode
);
377 return gen_rtx_CONST (to_mode
,
378 convert_memory_address (to_mode
, XEXP (x
, 0)));
383 /* For addition we can safely permute the conversion and addition
384 operation if one operand is a constant and converting the constant
385 does not change it or if one operand is a constant and we are
386 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
387 We can always safely permute them if we are making the address
389 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
)
390 || (GET_CODE (x
) == PLUS
391 && GET_CODE (XEXP (x
, 1)) == CONST_INT
392 && (XEXP (x
, 1) == convert_memory_address (to_mode
, XEXP (x
, 1))
393 || POINTERS_EXTEND_UNSIGNED
< 0)))
394 return gen_rtx_fmt_ee (GET_CODE (x
), to_mode
,
395 convert_memory_address (to_mode
, XEXP (x
, 0)),
403 return convert_modes (to_mode
, from_mode
,
404 x
, POINTERS_EXTEND_UNSIGNED
);
405 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
408 /* Return something equivalent to X but valid as a memory address
409 for something of mode MODE. When X is not itself valid, this
410 works by copying X or subexpressions of it into registers. */
413 memory_address (enum machine_mode mode
, rtx x
)
417 x
= convert_memory_address (Pmode
, x
);
419 /* By passing constant addresses through registers
420 we get a chance to cse them. */
421 if (! cse_not_expected
&& CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
))
422 x
= force_reg (Pmode
, x
);
424 /* We get better cse by rejecting indirect addressing at this stage.
425 Let the combiner create indirect addresses where appropriate.
426 For now, generate the code so that the subexpressions useful to share
427 are visible. But not if cse won't be done! */
430 if (! cse_not_expected
&& !REG_P (x
))
431 x
= break_out_memory_refs (x
);
433 /* At this point, any valid address is accepted. */
434 if (memory_address_p (mode
, x
))
437 /* If it was valid before but breaking out memory refs invalidated it,
438 use it the old way. */
439 if (memory_address_p (mode
, oldx
))
442 /* Perform machine-dependent transformations on X
443 in certain cases. This is not necessary since the code
444 below can handle all possible cases, but machine-dependent
445 transformations can make better code. */
446 LEGITIMIZE_ADDRESS (x
, oldx
, mode
, win
);
448 /* PLUS and MULT can appear in special ways
449 as the result of attempts to make an address usable for indexing.
450 Usually they are dealt with by calling force_operand, below.
451 But a sum containing constant terms is special
452 if removing them makes the sum a valid address:
453 then we generate that address in a register
454 and index off of it. We do this because it often makes
455 shorter code, and because the addresses thus generated
456 in registers often become common subexpressions. */
457 if (GET_CODE (x
) == PLUS
)
459 rtx constant_term
= const0_rtx
;
460 rtx y
= eliminate_constant_term (x
, &constant_term
);
461 if (constant_term
== const0_rtx
462 || ! memory_address_p (mode
, y
))
463 x
= force_operand (x
, NULL_RTX
);
466 y
= gen_rtx_PLUS (GET_MODE (x
), copy_to_reg (y
), constant_term
);
467 if (! memory_address_p (mode
, y
))
468 x
= force_operand (x
, NULL_RTX
);
474 else if (GET_CODE (x
) == MULT
|| GET_CODE (x
) == MINUS
)
475 x
= force_operand (x
, NULL_RTX
);
477 /* If we have a register that's an invalid address,
478 it must be a hard reg of the wrong class. Copy it to a pseudo. */
482 /* Last resort: copy the value to a register, since
483 the register is a valid address. */
485 x
= force_reg (Pmode
, x
);
492 if (flag_force_addr
&& ! cse_not_expected
&& !REG_P (x
))
494 x
= force_operand (x
, NULL_RTX
);
495 x
= force_reg (Pmode
, x
);
501 /* If we didn't change the address, we are done. Otherwise, mark
502 a reg as a pointer if we have REG or REG + CONST_INT. */
506 mark_reg_pointer (x
, BITS_PER_UNIT
);
507 else if (GET_CODE (x
) == PLUS
508 && REG_P (XEXP (x
, 0))
509 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
510 mark_reg_pointer (XEXP (x
, 0), BITS_PER_UNIT
);
512 /* OLDX may have been the address on a temporary. Update the address
513 to indicate that X is now used. */
514 update_temp_slot_address (oldx
, x
);
519 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
522 memory_address_noforce (enum machine_mode mode
, rtx x
)
524 int ambient_force_addr
= flag_force_addr
;
528 val
= memory_address (mode
, x
);
529 flag_force_addr
= ambient_force_addr
;
533 /* Convert a mem ref into one with a valid memory address.
534 Pass through anything else unchanged. */
537 validize_mem (rtx ref
)
541 ref
= use_anchored_address (ref
);
542 if (! (flag_force_addr
&& CONSTANT_ADDRESS_P (XEXP (ref
, 0)))
543 && memory_address_p (GET_MODE (ref
), XEXP (ref
, 0)))
546 /* Don't alter REF itself, since that is probably a stack slot. */
547 return replace_equiv_address (ref
, XEXP (ref
, 0));
550 /* If X is a memory reference to a member of an object block, try rewriting
551 it to use an anchor instead. Return the new memory reference on success
552 and the old one on failure. */
555 use_anchored_address (rtx x
)
558 HOST_WIDE_INT offset
;
560 if (!flag_section_anchors
)
566 /* Split the address into a base and offset. */
569 if (GET_CODE (base
) == CONST
570 && GET_CODE (XEXP (base
, 0)) == PLUS
571 && GET_CODE (XEXP (XEXP (base
, 0), 1)) == CONST_INT
)
573 offset
+= INTVAL (XEXP (XEXP (base
, 0), 1));
574 base
= XEXP (XEXP (base
, 0), 0);
577 /* Check whether BASE is suitable for anchors. */
578 if (GET_CODE (base
) != SYMBOL_REF
579 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base
)
580 || SYMBOL_REF_ANCHOR_P (base
)
581 || SYMBOL_REF_BLOCK (base
) == NULL
582 || !targetm
.use_anchors_for_symbol_p (base
))
585 /* Decide where BASE is going to be. */
586 place_block_symbol (base
);
588 /* Get the anchor we need to use. */
589 offset
+= SYMBOL_REF_BLOCK_OFFSET (base
);
590 base
= get_section_anchor (SYMBOL_REF_BLOCK (base
), offset
,
591 SYMBOL_REF_TLS_MODEL (base
));
593 /* Work out the offset from the anchor. */
594 offset
-= SYMBOL_REF_BLOCK_OFFSET (base
);
596 /* If we're going to run a CSE pass, force the anchor into a register.
597 We will then be able to reuse registers for several accesses, if the
598 target costs say that that's worthwhile. */
599 if (!cse_not_expected
)
600 base
= force_reg (GET_MODE (base
), base
);
602 return replace_equiv_address (x
, plus_constant (base
, offset
));
605 /* Copy the value or contents of X to a new temp reg and return that reg. */
610 rtx temp
= gen_reg_rtx (GET_MODE (x
));
612 /* If not an operand, must be an address with PLUS and MULT so
613 do the computation. */
614 if (! general_operand (x
, VOIDmode
))
615 x
= force_operand (x
, temp
);
618 emit_move_insn (temp
, x
);
623 /* Like copy_to_reg but always give the new register mode Pmode
624 in case X is a constant. */
627 copy_addr_to_reg (rtx x
)
629 return copy_to_mode_reg (Pmode
, x
);
632 /* Like copy_to_reg but always give the new register mode MODE
633 in case X is a constant. */
636 copy_to_mode_reg (enum machine_mode mode
, rtx x
)
638 rtx temp
= gen_reg_rtx (mode
);
640 /* If not an operand, must be an address with PLUS and MULT so
641 do the computation. */
642 if (! general_operand (x
, VOIDmode
))
643 x
= force_operand (x
, temp
);
645 gcc_assert (GET_MODE (x
) == mode
|| GET_MODE (x
) == VOIDmode
);
647 emit_move_insn (temp
, x
);
651 /* Load X into a register if it is not already one.
652 Use mode MODE for the register.
653 X should be valid for mode MODE, but it may be a constant which
654 is valid for all integer modes; that's why caller must specify MODE.
656 The caller must not alter the value in the register we return,
657 since we mark it as a "constant" register. */
660 force_reg (enum machine_mode mode
, rtx x
)
667 if (general_operand (x
, mode
))
669 temp
= gen_reg_rtx (mode
);
670 insn
= emit_move_insn (temp
, x
);
674 temp
= force_operand (x
, NULL_RTX
);
676 insn
= get_last_insn ();
679 rtx temp2
= gen_reg_rtx (mode
);
680 insn
= emit_move_insn (temp2
, temp
);
685 /* Let optimizers know that TEMP's value never changes
686 and that X can be substituted for it. Don't get confused
687 if INSN set something else (such as a SUBREG of TEMP). */
689 && (set
= single_set (insn
)) != 0
690 && SET_DEST (set
) == temp
691 && ! rtx_equal_p (x
, SET_SRC (set
)))
692 set_unique_reg_note (insn
, REG_EQUAL
, x
);
694 /* Let optimizers know that TEMP is a pointer, and if so, the
695 known alignment of that pointer. */
698 if (GET_CODE (x
) == SYMBOL_REF
)
700 align
= BITS_PER_UNIT
;
701 if (SYMBOL_REF_DECL (x
) && DECL_P (SYMBOL_REF_DECL (x
)))
702 align
= DECL_ALIGN (SYMBOL_REF_DECL (x
));
704 else if (GET_CODE (x
) == LABEL_REF
)
705 align
= BITS_PER_UNIT
;
706 else if (GET_CODE (x
) == CONST
707 && GET_CODE (XEXP (x
, 0)) == PLUS
708 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == SYMBOL_REF
709 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
)
711 rtx s
= XEXP (XEXP (x
, 0), 0);
712 rtx c
= XEXP (XEXP (x
, 0), 1);
716 if (SYMBOL_REF_DECL (s
) && DECL_P (SYMBOL_REF_DECL (s
)))
717 sa
= DECL_ALIGN (SYMBOL_REF_DECL (s
));
719 ca
= exact_log2 (INTVAL (c
) & -INTVAL (c
)) * BITS_PER_UNIT
;
721 align
= MIN (sa
, ca
);
723 else if (MEM_P (x
) && MEM_POINTER (x
))
724 align
= MEM_ALIGN (x
);
727 mark_reg_pointer (temp
, align
);
733 /* If X is a memory ref, copy its contents to a new temp reg and return
734 that reg. Otherwise, return X. */
737 force_not_mem (rtx x
)
741 if (!MEM_P (x
) || GET_MODE (x
) == BLKmode
)
744 temp
= gen_reg_rtx (GET_MODE (x
));
747 REG_POINTER (temp
) = 1;
749 emit_move_insn (temp
, x
);
753 /* Copy X to TARGET (if it's nonzero and a reg)
754 or to a new temp reg and return that reg.
755 MODE is the mode to use for X in case it is a constant. */
758 copy_to_suggested_reg (rtx x
, rtx target
, enum machine_mode mode
)
762 if (target
&& REG_P (target
))
765 temp
= gen_reg_rtx (mode
);
767 emit_move_insn (temp
, x
);
771 /* Return the mode to use to store a scalar of TYPE and MODE.
772 PUNSIGNEDP points to the signedness of the type and may be adjusted
773 to show what signedness to use on extension operations.
775 FOR_CALL is nonzero if this call is promoting args for a call. */
777 #if defined(PROMOTE_MODE) && !defined(PROMOTE_FUNCTION_MODE)
778 #define PROMOTE_FUNCTION_MODE PROMOTE_MODE
782 promote_mode (tree type
, enum machine_mode mode
, int *punsignedp
,
783 int for_call ATTRIBUTE_UNUSED
)
785 enum tree_code code
= TREE_CODE (type
);
786 int unsignedp
= *punsignedp
;
795 #ifdef PROMOTE_FUNCTION_MODE
796 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
797 case REAL_TYPE
: case OFFSET_TYPE
:
802 PROMOTE_FUNCTION_MODE (mode
, unsignedp
, type
);
807 PROMOTE_MODE (mode
, unsignedp
, type
);
813 #ifdef POINTERS_EXTEND_UNSIGNED
817 unsignedp
= POINTERS_EXTEND_UNSIGNED
;
825 *punsignedp
= unsignedp
;
829 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
830 This pops when ADJUST is positive. ADJUST need not be constant. */
833 adjust_stack (rtx adjust
)
837 if (adjust
== const0_rtx
)
840 /* We expect all variable sized adjustments to be multiple of
841 PREFERRED_STACK_BOUNDARY. */
842 if (GET_CODE (adjust
) == CONST_INT
)
843 stack_pointer_delta
-= INTVAL (adjust
);
845 temp
= expand_binop (Pmode
,
846 #ifdef STACK_GROWS_DOWNWARD
851 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
854 if (temp
!= stack_pointer_rtx
)
855 emit_move_insn (stack_pointer_rtx
, temp
);
858 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
859 This pushes when ADJUST is positive. ADJUST need not be constant. */
862 anti_adjust_stack (rtx adjust
)
866 if (adjust
== const0_rtx
)
869 /* We expect all variable sized adjustments to be multiple of
870 PREFERRED_STACK_BOUNDARY. */
871 if (GET_CODE (adjust
) == CONST_INT
)
872 stack_pointer_delta
+= INTVAL (adjust
);
874 temp
= expand_binop (Pmode
,
875 #ifdef STACK_GROWS_DOWNWARD
880 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
883 if (temp
!= stack_pointer_rtx
)
884 emit_move_insn (stack_pointer_rtx
, temp
);
887 /* Round the size of a block to be pushed up to the boundary required
888 by this machine. SIZE is the desired size, which need not be constant. */
891 round_push (rtx size
)
893 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
898 if (GET_CODE (size
) == CONST_INT
)
900 HOST_WIDE_INT
new = (INTVAL (size
) + align
- 1) / align
* align
;
902 if (INTVAL (size
) != new)
903 size
= GEN_INT (new);
907 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
908 but we know it can't. So add ourselves and then do
910 size
= expand_binop (Pmode
, add_optab
, size
, GEN_INT (align
- 1),
911 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
912 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
, GEN_INT (align
),
914 size
= expand_mult (Pmode
, size
, GEN_INT (align
), NULL_RTX
, 1);
920 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
921 to a previously-created save area. If no save area has been allocated,
922 this function will allocate one. If a save area is specified, it
923 must be of the proper mode.
925 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
926 are emitted at the current position. */
929 emit_stack_save (enum save_level save_level
, rtx
*psave
, rtx after
)
932 /* The default is that we use a move insn and save in a Pmode object. */
933 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
934 enum machine_mode mode
= STACK_SAVEAREA_MODE (save_level
);
936 /* See if this machine has anything special to do for this kind of save. */
939 #ifdef HAVE_save_stack_block
941 if (HAVE_save_stack_block
)
942 fcn
= gen_save_stack_block
;
945 #ifdef HAVE_save_stack_function
947 if (HAVE_save_stack_function
)
948 fcn
= gen_save_stack_function
;
951 #ifdef HAVE_save_stack_nonlocal
953 if (HAVE_save_stack_nonlocal
)
954 fcn
= gen_save_stack_nonlocal
;
961 /* If there is no save area and we have to allocate one, do so. Otherwise
962 verify the save area is the proper mode. */
966 if (mode
!= VOIDmode
)
968 if (save_level
== SAVE_NONLOCAL
)
969 *psave
= sa
= assign_stack_local (mode
, GET_MODE_SIZE (mode
), 0);
971 *psave
= sa
= gen_reg_rtx (mode
);
980 do_pending_stack_adjust ();
981 /* We must validize inside the sequence, to ensure that any instructions
982 created by the validize call also get moved to the right place. */
984 sa
= validize_mem (sa
);
985 emit_insn (fcn (sa
, stack_pointer_rtx
));
988 emit_insn_after (seq
, after
);
992 do_pending_stack_adjust ();
994 sa
= validize_mem (sa
);
995 emit_insn (fcn (sa
, stack_pointer_rtx
));
999 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1000 area made by emit_stack_save. If it is zero, we have nothing to do.
1002 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1003 current position. */
1006 emit_stack_restore (enum save_level save_level
, rtx sa
, rtx after
)
1008 /* The default is that we use a move insn. */
1009 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
1011 /* See if this machine has anything special to do for this kind of save. */
1014 #ifdef HAVE_restore_stack_block
1016 if (HAVE_restore_stack_block
)
1017 fcn
= gen_restore_stack_block
;
1020 #ifdef HAVE_restore_stack_function
1022 if (HAVE_restore_stack_function
)
1023 fcn
= gen_restore_stack_function
;
1026 #ifdef HAVE_restore_stack_nonlocal
1028 if (HAVE_restore_stack_nonlocal
)
1029 fcn
= gen_restore_stack_nonlocal
;
1038 sa
= validize_mem (sa
);
1039 /* These clobbers prevent the scheduler from moving
1040 references to variable arrays below the code
1041 that deletes (pops) the arrays. */
1042 emit_insn (gen_rtx_CLOBBER (VOIDmode
,
1043 gen_rtx_MEM (BLKmode
,
1044 gen_rtx_SCRATCH (VOIDmode
))));
1045 emit_insn (gen_rtx_CLOBBER (VOIDmode
,
1046 gen_rtx_MEM (BLKmode
, stack_pointer_rtx
)));
1049 discard_pending_stack_adjust ();
1056 emit_insn (fcn (stack_pointer_rtx
, sa
));
1059 emit_insn_after (seq
, after
);
1062 emit_insn (fcn (stack_pointer_rtx
, sa
));
1065 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1066 function. This function should be called whenever we allocate or
1067 deallocate dynamic stack space. */
1070 update_nonlocal_goto_save_area (void)
1075 /* The nonlocal_goto_save_area object is an array of N pointers. The
1076 first one is used for the frame pointer save; the rest are sized by
1077 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1078 of the stack save area slots. */
1079 t_save
= build4 (ARRAY_REF
, ptr_type_node
, cfun
->nonlocal_goto_save_area
,
1080 integer_one_node
, NULL_TREE
, NULL_TREE
);
1081 r_save
= expand_expr (t_save
, NULL_RTX
, VOIDmode
, EXPAND_WRITE
);
1083 emit_stack_save (SAVE_NONLOCAL
, &r_save
, NULL_RTX
);
1086 /* Return an rtx representing the address of an area of memory dynamically
1087 pushed on the stack. This region of memory is always aligned to
1088 a multiple of BIGGEST_ALIGNMENT.
1090 Any required stack pointer alignment is preserved.
1092 SIZE is an rtx representing the size of the area.
1093 TARGET is a place in which the address can be placed.
1095 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1098 allocate_dynamic_stack_space (rtx size
, rtx target
, int known_align
)
1100 /* If we're asking for zero bytes, it doesn't matter what we point
1101 to since we can't dereference it. But return a reasonable
1103 if (size
== const0_rtx
)
1104 return virtual_stack_dynamic_rtx
;
1106 /* Otherwise, show we're calling alloca or equivalent. */
1107 current_function_calls_alloca
= 1;
1109 /* Ensure the size is in the proper mode. */
1110 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1111 size
= convert_to_mode (Pmode
, size
, 1);
1113 /* We can't attempt to minimize alignment necessary, because we don't
1114 know the final value of preferred_stack_boundary yet while executing
1116 cfun
->preferred_stack_boundary
= PREFERRED_STACK_BOUNDARY
;
1118 /* We will need to ensure that the address we return is aligned to
1119 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1120 always know its final value at this point in the compilation (it
1121 might depend on the size of the outgoing parameter lists, for
1122 example), so we must align the value to be returned in that case.
1123 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1124 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1125 We must also do an alignment operation on the returned value if
1126 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1128 If we have to align, we must leave space in SIZE for the hole
1129 that might result from the alignment operation. */
1131 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1132 #define MUST_ALIGN 1
1134 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1139 = force_operand (plus_constant (size
,
1140 BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1143 #ifdef SETJMP_VIA_SAVE_AREA
1144 /* If setjmp restores regs from a save area in the stack frame,
1145 avoid clobbering the reg save area. Note that the offset of
1146 virtual_incoming_args_rtx includes the preallocated stack args space.
1147 It would be no problem to clobber that, but it's on the wrong side
1148 of the old save area.
1150 What used to happen is that, since we did not know for sure
1151 whether setjmp() was invoked until after RTL generation, we
1152 would use reg notes to store the "optimized" size and fix things
1153 up later. These days we know this information before we ever
1154 start building RTL so the reg notes are unnecessary. */
1155 if (!current_function_calls_setjmp
)
1157 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
1159 /* ??? Code below assumes that the save area needs maximal
1160 alignment. This constraint may be too strong. */
1161 gcc_assert (PREFERRED_STACK_BOUNDARY
== BIGGEST_ALIGNMENT
);
1163 if (GET_CODE (size
) == CONST_INT
)
1165 HOST_WIDE_INT
new = INTVAL (size
) / align
* align
;
1167 if (INTVAL (size
) != new)
1168 size
= GEN_INT (new);
1172 /* Since we know overflow is not possible, we avoid using
1173 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1174 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
,
1175 GEN_INT (align
), NULL_RTX
, 1);
1176 size
= expand_mult (Pmode
, size
,
1177 GEN_INT (align
), NULL_RTX
, 1);
1183 = expand_binop (Pmode
, sub_optab
, virtual_stack_dynamic_rtx
,
1184 stack_pointer_rtx
, NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1186 size
= expand_binop (Pmode
, add_optab
, size
, dynamic_offset
,
1187 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1189 #endif /* SETJMP_VIA_SAVE_AREA */
1191 /* Round the size to a multiple of the required stack alignment.
1192 Since the stack if presumed to be rounded before this allocation,
1193 this will maintain the required alignment.
1195 If the stack grows downward, we could save an insn by subtracting
1196 SIZE from the stack pointer and then aligning the stack pointer.
1197 The problem with this is that the stack pointer may be unaligned
1198 between the execution of the subtraction and alignment insns and
1199 some machines do not allow this. Even on those that do, some
1200 signal handlers malfunction if a signal should occur between those
1201 insns. Since this is an extremely rare event, we have no reliable
1202 way of knowing which systems have this problem. So we avoid even
1203 momentarily mis-aligning the stack. */
1205 /* If we added a variable amount to SIZE,
1206 we can no longer assume it is aligned. */
1207 #if !defined (SETJMP_VIA_SAVE_AREA)
1208 if (MUST_ALIGN
|| known_align
% PREFERRED_STACK_BOUNDARY
!= 0)
1210 size
= round_push (size
);
1212 do_pending_stack_adjust ();
1214 /* We ought to be called always on the toplevel and stack ought to be aligned
1216 gcc_assert (!(stack_pointer_delta
1217 % (PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
)));
1219 /* If needed, check that we have the required amount of stack. Take into
1220 account what has already been checked. */
1221 if (flag_stack_check
&& ! STACK_CHECK_BUILTIN
)
1222 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE
+ STACK_CHECK_PROTECT
, size
);
1224 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1225 if (target
== 0 || !REG_P (target
)
1226 || REGNO (target
) < FIRST_PSEUDO_REGISTER
1227 || GET_MODE (target
) != Pmode
)
1228 target
= gen_reg_rtx (Pmode
);
1230 mark_reg_pointer (target
, known_align
);
1232 /* Perform the required allocation from the stack. Some systems do
1233 this differently than simply incrementing/decrementing from the
1234 stack pointer, such as acquiring the space by calling malloc(). */
1235 #ifdef HAVE_allocate_stack
1236 if (HAVE_allocate_stack
)
1238 enum machine_mode mode
= STACK_SIZE_MODE
;
1239 insn_operand_predicate_fn pred
;
1241 /* We don't have to check against the predicate for operand 0 since
1242 TARGET is known to be a pseudo of the proper mode, which must
1243 be valid for the operand. For operand 1, convert to the
1244 proper mode and validate. */
1245 if (mode
== VOIDmode
)
1246 mode
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].mode
;
1248 pred
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].predicate
;
1249 if (pred
&& ! ((*pred
) (size
, mode
)))
1250 size
= copy_to_mode_reg (mode
, convert_to_mode (mode
, size
, 1));
1252 emit_insn (gen_allocate_stack (target
, size
));
1257 #ifndef STACK_GROWS_DOWNWARD
1258 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1261 /* Check stack bounds if necessary. */
1262 if (current_function_limit_stack
)
1265 rtx space_available
= gen_label_rtx ();
1266 #ifdef STACK_GROWS_DOWNWARD
1267 available
= expand_binop (Pmode
, sub_optab
,
1268 stack_pointer_rtx
, stack_limit_rtx
,
1269 NULL_RTX
, 1, OPTAB_WIDEN
);
1271 available
= expand_binop (Pmode
, sub_optab
,
1272 stack_limit_rtx
, stack_pointer_rtx
,
1273 NULL_RTX
, 1, OPTAB_WIDEN
);
1275 emit_cmp_and_jump_insns (available
, size
, GEU
, NULL_RTX
, Pmode
, 1,
1279 emit_insn (gen_trap ());
1282 error ("stack limits not supported on this target");
1284 emit_label (space_available
);
1287 anti_adjust_stack (size
);
1289 #ifdef STACK_GROWS_DOWNWARD
1290 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1296 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1297 but we know it can't. So add ourselves and then do
1299 target
= expand_binop (Pmode
, add_optab
, target
,
1300 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1301 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1302 target
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, target
,
1303 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1305 target
= expand_mult (Pmode
, target
,
1306 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1310 /* Record the new stack level for nonlocal gotos. */
1311 if (cfun
->nonlocal_goto_save_area
!= 0)
1312 update_nonlocal_goto_save_area ();
1317 /* A front end may want to override GCC's stack checking by providing a
1318 run-time routine to call to check the stack, so provide a mechanism for
1319 calling that routine. */
1321 static GTY(()) rtx stack_check_libfunc
;
1324 set_stack_check_libfunc (rtx libfunc
)
1326 stack_check_libfunc
= libfunc
;
1329 /* Emit one stack probe at ADDRESS, an address within the stack. */
1332 emit_stack_probe (rtx address
)
1334 rtx memref
= gen_rtx_MEM (word_mode
, address
);
1336 MEM_VOLATILE_P (memref
) = 1;
1338 if (STACK_CHECK_PROBE_LOAD
)
1339 emit_move_insn (gen_reg_rtx (word_mode
), memref
);
1341 emit_move_insn (memref
, const0_rtx
);
1344 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1345 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1346 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1347 subtract from the stack. If SIZE is constant, this is done
1348 with a fixed number of probes. Otherwise, we must make a loop. */
1350 #ifdef STACK_GROWS_DOWNWARD
1351 #define STACK_GROW_OP MINUS
1353 #define STACK_GROW_OP PLUS
1357 probe_stack_range (HOST_WIDE_INT first
, rtx size
)
1359 /* First ensure SIZE is Pmode. */
1360 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1361 size
= convert_to_mode (Pmode
, size
, 1);
1363 /* Next see if the front end has set up a function for us to call to
1365 if (stack_check_libfunc
!= 0)
1367 rtx addr
= memory_address (QImode
,
1368 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1370 plus_constant (size
, first
)));
1372 addr
= convert_memory_address (ptr_mode
, addr
);
1373 emit_library_call (stack_check_libfunc
, LCT_NORMAL
, VOIDmode
, 1, addr
,
1377 /* Next see if we have an insn to check the stack. Use it if so. */
1378 #ifdef HAVE_check_stack
1379 else if (HAVE_check_stack
)
1381 insn_operand_predicate_fn pred
;
1383 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1385 plus_constant (size
, first
)),
1388 pred
= insn_data
[(int) CODE_FOR_check_stack
].operand
[0].predicate
;
1389 if (pred
&& ! ((*pred
) (last_addr
, Pmode
)))
1390 last_addr
= copy_to_mode_reg (Pmode
, last_addr
);
1392 emit_insn (gen_check_stack (last_addr
));
1396 /* If we have to generate explicit probes, see if we have a constant
1397 small number of them to generate. If so, that's the easy case. */
1398 else if (GET_CODE (size
) == CONST_INT
1399 && INTVAL (size
) < 10 * STACK_CHECK_PROBE_INTERVAL
)
1401 HOST_WIDE_INT offset
;
1403 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1404 for values of N from 1 until it exceeds LAST. If only one
1405 probe is needed, this will not generate any code. Then probe
1407 for (offset
= first
+ STACK_CHECK_PROBE_INTERVAL
;
1408 offset
< INTVAL (size
);
1409 offset
= offset
+ STACK_CHECK_PROBE_INTERVAL
)
1410 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1414 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1416 plus_constant (size
, first
)));
1419 /* In the variable case, do the same as above, but in a loop. We emit loop
1420 notes so that loop optimization can be done. */
1424 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1426 GEN_INT (first
+ STACK_CHECK_PROBE_INTERVAL
)),
1429 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1431 plus_constant (size
, first
)),
1433 rtx incr
= GEN_INT (STACK_CHECK_PROBE_INTERVAL
);
1434 rtx loop_lab
= gen_label_rtx ();
1435 rtx test_lab
= gen_label_rtx ();
1436 rtx end_lab
= gen_label_rtx ();
1439 if (!REG_P (test_addr
)
1440 || REGNO (test_addr
) < FIRST_PSEUDO_REGISTER
)
1441 test_addr
= force_reg (Pmode
, test_addr
);
1443 emit_jump (test_lab
);
1445 emit_label (loop_lab
);
1446 emit_stack_probe (test_addr
);
1448 #ifdef STACK_GROWS_DOWNWARD
1449 #define CMP_OPCODE GTU
1450 temp
= expand_binop (Pmode
, sub_optab
, test_addr
, incr
, test_addr
,
1453 #define CMP_OPCODE LTU
1454 temp
= expand_binop (Pmode
, add_optab
, test_addr
, incr
, test_addr
,
1458 gcc_assert (temp
== test_addr
);
1460 emit_label (test_lab
);
1461 emit_cmp_and_jump_insns (test_addr
, last_addr
, CMP_OPCODE
,
1462 NULL_RTX
, Pmode
, 1, loop_lab
);
1463 emit_jump (end_lab
);
1464 emit_label (end_lab
);
1466 emit_stack_probe (last_addr
);
1470 /* Return an rtx representing the register or memory location
1471 in which a scalar value of data type VALTYPE
1472 was returned by a function call to function FUNC.
1473 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1474 function is known, otherwise 0.
1475 OUTGOING is 1 if on a machine with register windows this function
1476 should return the register in which the function will put its result
1480 hard_function_value (tree valtype
, tree func
, tree fntype
,
1481 int outgoing ATTRIBUTE_UNUSED
)
1485 val
= targetm
.calls
.function_value (valtype
, func
? func
: fntype
, outgoing
);
1488 && GET_MODE (val
) == BLKmode
)
1490 unsigned HOST_WIDE_INT bytes
= int_size_in_bytes (valtype
);
1491 enum machine_mode tmpmode
;
1493 /* int_size_in_bytes can return -1. We don't need a check here
1494 since the value of bytes will then be large enough that no
1495 mode will match anyway. */
1497 for (tmpmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
1498 tmpmode
!= VOIDmode
;
1499 tmpmode
= GET_MODE_WIDER_MODE (tmpmode
))
1501 /* Have we found a large enough mode? */
1502 if (GET_MODE_SIZE (tmpmode
) >= bytes
)
1506 /* No suitable mode found. */
1507 gcc_assert (tmpmode
!= VOIDmode
);
1509 PUT_MODE (val
, tmpmode
);
1514 /* Return an rtx representing the register or memory location
1515 in which a scalar value of mode MODE was returned by a library call. */
1518 hard_libcall_value (enum machine_mode mode
)
1520 return LIBCALL_VALUE (mode
);
1523 /* Look up the tree code for a given rtx code
1524 to provide the arithmetic operation for REAL_ARITHMETIC.
1525 The function returns an int because the caller may not know
1526 what `enum tree_code' means. */
1529 rtx_to_tree_code (enum rtx_code code
)
1531 enum tree_code tcode
;
1554 tcode
= LAST_AND_UNUSED_TREE_CODE
;
1557 return ((int) tcode
);
1560 #include "gt-explow.h"