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 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
25 #include "coretypes.h"
35 #include "hard-reg-set.h"
36 #include "insn-config.h"
39 #include "langhooks.h"
41 static rtx
break_out_memory_refs (rtx
);
42 static void emit_stack_probe (rtx
);
45 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
48 trunc_int_for_mode (HOST_WIDE_INT c
, enum machine_mode mode
)
50 int width
= GET_MODE_BITSIZE (mode
);
52 /* You want to truncate to a _what_? */
53 gcc_assert (SCALAR_INT_MODE_P (mode
));
55 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
57 return c
& 1 ? STORE_FLAG_VALUE
: 0;
59 /* Sign-extend for the requested mode. */
61 if (width
< HOST_BITS_PER_WIDE_INT
)
63 HOST_WIDE_INT sign
= 1;
73 /* Return an rtx for the sum of X and the integer C. */
76 plus_constant (rtx x
, HOST_WIDE_INT c
)
80 enum machine_mode mode
;
96 return GEN_INT (INTVAL (x
) + c
);
100 unsigned HOST_WIDE_INT l1
= CONST_DOUBLE_LOW (x
);
101 HOST_WIDE_INT h1
= CONST_DOUBLE_HIGH (x
);
102 unsigned HOST_WIDE_INT l2
= c
;
103 HOST_WIDE_INT h2
= c
< 0 ? ~0 : 0;
104 unsigned HOST_WIDE_INT lv
;
107 add_double (l1
, h1
, l2
, h2
, &lv
, &hv
);
109 return immed_double_const (lv
, hv
, VOIDmode
);
113 /* If this is a reference to the constant pool, try replacing it with
114 a reference to a new constant. If the resulting address isn't
115 valid, don't return it because we have no way to validize it. */
116 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
117 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
120 = force_const_mem (GET_MODE (x
),
121 plus_constant (get_pool_constant (XEXP (x
, 0)),
123 if (memory_address_p (GET_MODE (tem
), XEXP (tem
, 0)))
129 /* If adding to something entirely constant, set a flag
130 so that we can add a CONST around the result. */
141 /* The interesting case is adding the integer to a sum.
142 Look for constant term in the sum and combine
143 with C. For an integer constant term, we make a combined
144 integer. For a constant term that is not an explicit integer,
145 we cannot really combine, but group them together anyway.
147 Restart or use a recursive call in case the remaining operand is
148 something that we handle specially, such as a SYMBOL_REF.
150 We may not immediately return from the recursive call here, lest
151 all_constant gets lost. */
153 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
)
155 c
+= INTVAL (XEXP (x
, 1));
157 if (GET_MODE (x
) != VOIDmode
)
158 c
= trunc_int_for_mode (c
, GET_MODE (x
));
163 else if (CONSTANT_P (XEXP (x
, 1)))
165 x
= gen_rtx_PLUS (mode
, XEXP (x
, 0), plus_constant (XEXP (x
, 1), c
));
168 else if (find_constant_term_loc (&y
))
170 /* We need to be careful since X may be shared and we can't
171 modify it in place. */
172 rtx copy
= copy_rtx (x
);
173 rtx
*const_loc
= find_constant_term_loc (©
);
175 *const_loc
= plus_constant (*const_loc
, c
);
186 x
= gen_rtx_PLUS (mode
, x
, GEN_INT (c
));
188 if (GET_CODE (x
) == SYMBOL_REF
|| GET_CODE (x
) == LABEL_REF
)
190 else if (all_constant
)
191 return gen_rtx_CONST (mode
, x
);
196 /* If X is a sum, return a new sum like X but lacking any constant terms.
197 Add all the removed constant terms into *CONSTPTR.
198 X itself is not altered. The result != X if and only if
199 it is not isomorphic to X. */
202 eliminate_constant_term (rtx x
, rtx
*constptr
)
207 if (GET_CODE (x
) != PLUS
)
210 /* First handle constants appearing at this level explicitly. */
211 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
212 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
), *constptr
,
214 && GET_CODE (tem
) == CONST_INT
)
217 return eliminate_constant_term (XEXP (x
, 0), constptr
);
221 x0
= eliminate_constant_term (XEXP (x
, 0), &tem
);
222 x1
= eliminate_constant_term (XEXP (x
, 1), &tem
);
223 if ((x1
!= XEXP (x
, 1) || x0
!= XEXP (x
, 0))
224 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
),
226 && GET_CODE (tem
) == CONST_INT
)
229 return gen_rtx_PLUS (GET_MODE (x
), x0
, x1
);
235 /* Return an rtx for the size in bytes of the value of EXP. */
242 if (TREE_CODE (exp
) == WITH_SIZE_EXPR
)
243 size
= TREE_OPERAND (exp
, 1);
245 size
= SUBSTITUTE_PLACEHOLDER_IN_EXPR (lang_hooks
.expr_size (exp
), exp
);
247 return expand_expr (size
, NULL_RTX
, TYPE_MODE (sizetype
), 0);
250 /* Return a wide integer for the size in bytes of the value of EXP, or -1
251 if the size can vary or is larger than an integer. */
254 int_expr_size (tree exp
)
258 if (TREE_CODE (exp
) == WITH_SIZE_EXPR
)
259 size
= TREE_OPERAND (exp
, 1);
261 size
= lang_hooks
.expr_size (exp
);
263 if (size
== 0 || !host_integerp (size
, 0))
266 return tree_low_cst (size
, 0);
269 /* Return a copy of X in which all memory references
270 and all constants that involve symbol refs
271 have been replaced with new temporary registers.
272 Also emit code to load the memory locations and constants
273 into those registers.
275 If X contains no such constants or memory references,
276 X itself (not a copy) is returned.
278 If a constant is found in the address that is not a legitimate constant
279 in an insn, it is left alone in the hope that it might be valid in the
282 X may contain no arithmetic except addition, subtraction and multiplication.
283 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
286 break_out_memory_refs (rtx x
)
289 || (CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
)
290 && GET_MODE (x
) != VOIDmode
))
291 x
= force_reg (GET_MODE (x
), x
);
292 else if (GET_CODE (x
) == PLUS
|| GET_CODE (x
) == MINUS
293 || GET_CODE (x
) == MULT
)
295 rtx op0
= break_out_memory_refs (XEXP (x
, 0));
296 rtx op1
= break_out_memory_refs (XEXP (x
, 1));
298 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
299 x
= gen_rtx_fmt_ee (GET_CODE (x
), Pmode
, op0
, op1
);
305 /* Given X, a memory address in ptr_mode, convert it to an address
306 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
307 the fact that pointers are not allowed to overflow by commuting arithmetic
308 operations over conversions so that address arithmetic insns can be
312 convert_memory_address (enum machine_mode to_mode ATTRIBUTE_UNUSED
,
315 #ifndef POINTERS_EXTEND_UNSIGNED
316 gcc_assert (GET_MODE (x
) == to_mode
|| GET_MODE (x
) == VOIDmode
);
318 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
319 enum machine_mode from_mode
;
323 /* If X already has the right mode, just return it. */
324 if (GET_MODE (x
) == to_mode
)
327 from_mode
= to_mode
== ptr_mode
? Pmode
: ptr_mode
;
329 /* Here we handle some special cases. If none of them apply, fall through
330 to the default case. */
331 switch (GET_CODE (x
))
335 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
))
337 else if (POINTERS_EXTEND_UNSIGNED
< 0)
339 else if (POINTERS_EXTEND_UNSIGNED
> 0)
343 temp
= simplify_unary_operation (code
, to_mode
, x
, from_mode
);
349 if ((SUBREG_PROMOTED_VAR_P (x
) || REG_POINTER (SUBREG_REG (x
)))
350 && GET_MODE (SUBREG_REG (x
)) == to_mode
)
351 return SUBREG_REG (x
);
355 temp
= gen_rtx_LABEL_REF (to_mode
, XEXP (x
, 0));
356 LABEL_REF_NONLOCAL_P (temp
) = LABEL_REF_NONLOCAL_P (x
);
361 temp
= shallow_copy_rtx (x
);
362 PUT_MODE (temp
, to_mode
);
367 return gen_rtx_CONST (to_mode
,
368 convert_memory_address (to_mode
, XEXP (x
, 0)));
373 /* For addition we can safely permute the conversion and addition
374 operation if one operand is a constant and converting the constant
375 does not change it. We can always safely permute them if we are
376 making the address narrower. */
377 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
)
378 || (GET_CODE (x
) == PLUS
379 && GET_CODE (XEXP (x
, 1)) == CONST_INT
380 && XEXP (x
, 1) == convert_memory_address (to_mode
, XEXP (x
, 1))))
381 return gen_rtx_fmt_ee (GET_CODE (x
), to_mode
,
382 convert_memory_address (to_mode
, XEXP (x
, 0)),
390 return convert_modes (to_mode
, from_mode
,
391 x
, POINTERS_EXTEND_UNSIGNED
);
392 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
395 /* Return something equivalent to X but valid as a memory address
396 for something of mode MODE. When X is not itself valid, this
397 works by copying X or subexpressions of it into registers. */
400 memory_address (enum machine_mode mode
, rtx x
)
404 x
= convert_memory_address (Pmode
, x
);
406 /* By passing constant addresses through registers
407 we get a chance to cse them. */
408 if (! cse_not_expected
&& CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
))
409 x
= force_reg (Pmode
, x
);
411 /* We get better cse by rejecting indirect addressing at this stage.
412 Let the combiner create indirect addresses where appropriate.
413 For now, generate the code so that the subexpressions useful to share
414 are visible. But not if cse won't be done! */
417 if (! cse_not_expected
&& !REG_P (x
))
418 x
= break_out_memory_refs (x
);
420 /* At this point, any valid address is accepted. */
421 if (memory_address_p (mode
, x
))
424 /* If it was valid before but breaking out memory refs invalidated it,
425 use it the old way. */
426 if (memory_address_p (mode
, oldx
))
429 /* Perform machine-dependent transformations on X
430 in certain cases. This is not necessary since the code
431 below can handle all possible cases, but machine-dependent
432 transformations can make better code. */
433 LEGITIMIZE_ADDRESS (x
, oldx
, mode
, win
);
435 /* PLUS and MULT can appear in special ways
436 as the result of attempts to make an address usable for indexing.
437 Usually they are dealt with by calling force_operand, below.
438 But a sum containing constant terms is special
439 if removing them makes the sum a valid address:
440 then we generate that address in a register
441 and index off of it. We do this because it often makes
442 shorter code, and because the addresses thus generated
443 in registers often become common subexpressions. */
444 if (GET_CODE (x
) == PLUS
)
446 rtx constant_term
= const0_rtx
;
447 rtx y
= eliminate_constant_term (x
, &constant_term
);
448 if (constant_term
== const0_rtx
449 || ! memory_address_p (mode
, y
))
450 x
= force_operand (x
, NULL_RTX
);
453 y
= gen_rtx_PLUS (GET_MODE (x
), copy_to_reg (y
), constant_term
);
454 if (! memory_address_p (mode
, y
))
455 x
= force_operand (x
, NULL_RTX
);
461 else if (GET_CODE (x
) == MULT
|| GET_CODE (x
) == MINUS
)
462 x
= force_operand (x
, NULL_RTX
);
464 /* If we have a register that's an invalid address,
465 it must be a hard reg of the wrong class. Copy it to a pseudo. */
469 /* Last resort: copy the value to a register, since
470 the register is a valid address. */
472 x
= force_reg (Pmode
, x
);
479 if (flag_force_addr
&& ! cse_not_expected
&& !REG_P (x
)
480 /* Don't copy an addr via a reg if it is one of our stack slots. */
481 && ! (GET_CODE (x
) == PLUS
482 && (XEXP (x
, 0) == virtual_stack_vars_rtx
483 || XEXP (x
, 0) == virtual_incoming_args_rtx
)))
485 if (general_operand (x
, Pmode
))
486 x
= force_reg (Pmode
, x
);
488 x
= force_operand (x
, NULL_RTX
);
494 /* If we didn't change the address, we are done. Otherwise, mark
495 a reg as a pointer if we have REG or REG + CONST_INT. */
499 mark_reg_pointer (x
, BITS_PER_UNIT
);
500 else if (GET_CODE (x
) == PLUS
501 && REG_P (XEXP (x
, 0))
502 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
503 mark_reg_pointer (XEXP (x
, 0), BITS_PER_UNIT
);
505 /* OLDX may have been the address on a temporary. Update the address
506 to indicate that X is now used. */
507 update_temp_slot_address (oldx
, x
);
512 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
515 memory_address_noforce (enum machine_mode mode
, rtx x
)
517 int ambient_force_addr
= flag_force_addr
;
521 val
= memory_address (mode
, x
);
522 flag_force_addr
= ambient_force_addr
;
526 /* Convert a mem ref into one with a valid memory address.
527 Pass through anything else unchanged. */
530 validize_mem (rtx ref
)
534 if (! (flag_force_addr
&& CONSTANT_ADDRESS_P (XEXP (ref
, 0)))
535 && memory_address_p (GET_MODE (ref
), XEXP (ref
, 0)))
538 /* Don't alter REF itself, since that is probably a stack slot. */
539 return replace_equiv_address (ref
, XEXP (ref
, 0));
542 /* Copy the value or contents of X to a new temp reg and return that reg. */
547 rtx temp
= gen_reg_rtx (GET_MODE (x
));
549 /* If not an operand, must be an address with PLUS and MULT so
550 do the computation. */
551 if (! general_operand (x
, VOIDmode
))
552 x
= force_operand (x
, temp
);
555 emit_move_insn (temp
, x
);
560 /* Like copy_to_reg but always give the new register mode Pmode
561 in case X is a constant. */
564 copy_addr_to_reg (rtx x
)
566 return copy_to_mode_reg (Pmode
, x
);
569 /* Like copy_to_reg but always give the new register mode MODE
570 in case X is a constant. */
573 copy_to_mode_reg (enum machine_mode mode
, rtx x
)
575 rtx temp
= gen_reg_rtx (mode
);
577 /* If not an operand, must be an address with PLUS and MULT so
578 do the computation. */
579 if (! general_operand (x
, VOIDmode
))
580 x
= force_operand (x
, temp
);
582 gcc_assert (GET_MODE (x
) == mode
|| GET_MODE (x
) == VOIDmode
);
584 emit_move_insn (temp
, x
);
588 /* Load X into a register if it is not already one.
589 Use mode MODE for the register.
590 X should be valid for mode MODE, but it may be a constant which
591 is valid for all integer modes; that's why caller must specify MODE.
593 The caller must not alter the value in the register we return,
594 since we mark it as a "constant" register. */
597 force_reg (enum machine_mode mode
, rtx x
)
604 if (general_operand (x
, mode
))
606 temp
= gen_reg_rtx (mode
);
607 insn
= emit_move_insn (temp
, x
);
611 temp
= force_operand (x
, NULL_RTX
);
613 insn
= get_last_insn ();
616 rtx temp2
= gen_reg_rtx (mode
);
617 insn
= emit_move_insn (temp2
, temp
);
622 /* Let optimizers know that TEMP's value never changes
623 and that X can be substituted for it. Don't get confused
624 if INSN set something else (such as a SUBREG of TEMP). */
626 && (set
= single_set (insn
)) != 0
627 && SET_DEST (set
) == temp
628 && ! rtx_equal_p (x
, SET_SRC (set
)))
629 set_unique_reg_note (insn
, REG_EQUAL
, x
);
631 /* Let optimizers know that TEMP is a pointer, and if so, the
632 known alignment of that pointer. */
635 if (GET_CODE (x
) == SYMBOL_REF
)
637 align
= BITS_PER_UNIT
;
638 if (SYMBOL_REF_DECL (x
) && DECL_P (SYMBOL_REF_DECL (x
)))
639 align
= DECL_ALIGN (SYMBOL_REF_DECL (x
));
641 else if (GET_CODE (x
) == LABEL_REF
)
642 align
= BITS_PER_UNIT
;
643 else if (GET_CODE (x
) == CONST
644 && GET_CODE (XEXP (x
, 0)) == PLUS
645 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == SYMBOL_REF
646 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
)
648 rtx s
= XEXP (XEXP (x
, 0), 0);
649 rtx c
= XEXP (XEXP (x
, 0), 1);
653 if (SYMBOL_REF_DECL (s
) && DECL_P (SYMBOL_REF_DECL (s
)))
654 sa
= DECL_ALIGN (SYMBOL_REF_DECL (s
));
656 ca
= exact_log2 (INTVAL (c
) & -INTVAL (c
)) * BITS_PER_UNIT
;
658 align
= MIN (sa
, ca
);
662 mark_reg_pointer (temp
, align
);
668 /* If X is a memory ref, copy its contents to a new temp reg and return
669 that reg. Otherwise, return X. */
672 force_not_mem (rtx x
)
676 if (!MEM_P (x
) || GET_MODE (x
) == BLKmode
)
679 temp
= gen_reg_rtx (GET_MODE (x
));
682 REG_POINTER (temp
) = 1;
684 emit_move_insn (temp
, x
);
688 /* Copy X to TARGET (if it's nonzero and a reg)
689 or to a new temp reg and return that reg.
690 MODE is the mode to use for X in case it is a constant. */
693 copy_to_suggested_reg (rtx x
, rtx target
, enum machine_mode mode
)
697 if (target
&& REG_P (target
))
700 temp
= gen_reg_rtx (mode
);
702 emit_move_insn (temp
, x
);
706 /* Return the mode to use to store a scalar of TYPE and MODE.
707 PUNSIGNEDP points to the signedness of the type and may be adjusted
708 to show what signedness to use on extension operations.
710 FOR_CALL is nonzero if this call is promoting args for a call. */
712 #if defined(PROMOTE_MODE) && !defined(PROMOTE_FUNCTION_MODE)
713 #define PROMOTE_FUNCTION_MODE PROMOTE_MODE
717 promote_mode (tree type
, enum machine_mode mode
, int *punsignedp
,
718 int for_call ATTRIBUTE_UNUSED
)
720 enum tree_code code
= TREE_CODE (type
);
721 int unsignedp
= *punsignedp
;
730 #ifdef PROMOTE_FUNCTION_MODE
731 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
732 case CHAR_TYPE
: case REAL_TYPE
: case OFFSET_TYPE
:
737 PROMOTE_FUNCTION_MODE (mode
, unsignedp
, type
);
742 PROMOTE_MODE (mode
, unsignedp
, type
);
748 #ifdef POINTERS_EXTEND_UNSIGNED
752 unsignedp
= POINTERS_EXTEND_UNSIGNED
;
760 *punsignedp
= unsignedp
;
764 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
765 This pops when ADJUST is positive. ADJUST need not be constant. */
768 adjust_stack (rtx adjust
)
772 if (adjust
== const0_rtx
)
775 /* We expect all variable sized adjustments to be multiple of
776 PREFERRED_STACK_BOUNDARY. */
777 if (GET_CODE (adjust
) == CONST_INT
)
778 stack_pointer_delta
-= INTVAL (adjust
);
780 temp
= expand_binop (Pmode
,
781 #ifdef STACK_GROWS_DOWNWARD
786 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
789 if (temp
!= stack_pointer_rtx
)
790 emit_move_insn (stack_pointer_rtx
, temp
);
793 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
794 This pushes when ADJUST is positive. ADJUST need not be constant. */
797 anti_adjust_stack (rtx adjust
)
801 if (adjust
== const0_rtx
)
804 /* We expect all variable sized adjustments to be multiple of
805 PREFERRED_STACK_BOUNDARY. */
806 if (GET_CODE (adjust
) == CONST_INT
)
807 stack_pointer_delta
+= INTVAL (adjust
);
809 temp
= expand_binop (Pmode
,
810 #ifdef STACK_GROWS_DOWNWARD
815 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
818 if (temp
!= stack_pointer_rtx
)
819 emit_move_insn (stack_pointer_rtx
, temp
);
822 /* Round the size of a block to be pushed up to the boundary required
823 by this machine. SIZE is the desired size, which need not be constant. */
826 round_push (rtx size
)
828 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
833 if (GET_CODE (size
) == CONST_INT
)
835 HOST_WIDE_INT
new = (INTVAL (size
) + align
- 1) / align
* align
;
837 if (INTVAL (size
) != new)
838 size
= GEN_INT (new);
842 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
843 but we know it can't. So add ourselves and then do
845 size
= expand_binop (Pmode
, add_optab
, size
, GEN_INT (align
- 1),
846 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
847 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
, GEN_INT (align
),
849 size
= expand_mult (Pmode
, size
, GEN_INT (align
), NULL_RTX
, 1);
855 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
856 to a previously-created save area. If no save area has been allocated,
857 this function will allocate one. If a save area is specified, it
858 must be of the proper mode.
860 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
861 are emitted at the current position. */
864 emit_stack_save (enum save_level save_level
, rtx
*psave
, rtx after
)
867 /* The default is that we use a move insn and save in a Pmode object. */
868 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
869 enum machine_mode mode
= STACK_SAVEAREA_MODE (save_level
);
871 /* See if this machine has anything special to do for this kind of save. */
874 #ifdef HAVE_save_stack_block
876 if (HAVE_save_stack_block
)
877 fcn
= gen_save_stack_block
;
880 #ifdef HAVE_save_stack_function
882 if (HAVE_save_stack_function
)
883 fcn
= gen_save_stack_function
;
886 #ifdef HAVE_save_stack_nonlocal
888 if (HAVE_save_stack_nonlocal
)
889 fcn
= gen_save_stack_nonlocal
;
896 /* If there is no save area and we have to allocate one, do so. Otherwise
897 verify the save area is the proper mode. */
901 if (mode
!= VOIDmode
)
903 if (save_level
== SAVE_NONLOCAL
)
904 *psave
= sa
= assign_stack_local (mode
, GET_MODE_SIZE (mode
), 0);
906 *psave
= sa
= gen_reg_rtx (mode
);
915 do_pending_stack_adjust ();
916 /* We must validize inside the sequence, to ensure that any instructions
917 created by the validize call also get moved to the right place. */
919 sa
= validize_mem (sa
);
920 emit_insn (fcn (sa
, stack_pointer_rtx
));
923 emit_insn_after (seq
, after
);
927 do_pending_stack_adjust ();
929 sa
= validize_mem (sa
);
930 emit_insn (fcn (sa
, stack_pointer_rtx
));
934 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
935 area made by emit_stack_save. If it is zero, we have nothing to do.
937 Put any emitted insns after insn AFTER, if nonzero, otherwise at
941 emit_stack_restore (enum save_level save_level
, rtx sa
, rtx after
)
943 /* The default is that we use a move insn. */
944 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
946 /* See if this machine has anything special to do for this kind of save. */
949 #ifdef HAVE_restore_stack_block
951 if (HAVE_restore_stack_block
)
952 fcn
= gen_restore_stack_block
;
955 #ifdef HAVE_restore_stack_function
957 if (HAVE_restore_stack_function
)
958 fcn
= gen_restore_stack_function
;
961 #ifdef HAVE_restore_stack_nonlocal
963 if (HAVE_restore_stack_nonlocal
)
964 fcn
= gen_restore_stack_nonlocal
;
973 sa
= validize_mem (sa
);
974 /* These clobbers prevent the scheduler from moving
975 references to variable arrays below the code
976 that deletes (pops) the arrays. */
977 emit_insn (gen_rtx_CLOBBER (VOIDmode
,
978 gen_rtx_MEM (BLKmode
,
979 gen_rtx_SCRATCH (VOIDmode
))));
980 emit_insn (gen_rtx_CLOBBER (VOIDmode
,
981 gen_rtx_MEM (BLKmode
, stack_pointer_rtx
)));
984 discard_pending_stack_adjust ();
991 emit_insn (fcn (stack_pointer_rtx
, sa
));
994 emit_insn_after (seq
, after
);
997 emit_insn (fcn (stack_pointer_rtx
, sa
));
1000 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1001 function. This function should be called whenever we allocate or
1002 deallocate dynamic stack space. */
1005 update_nonlocal_goto_save_area (void)
1010 /* The nonlocal_goto_save_area object is an array of N pointers. The
1011 first one is used for the frame pointer save; the rest are sized by
1012 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1013 of the stack save area slots. */
1014 t_save
= build4 (ARRAY_REF
, ptr_type_node
, cfun
->nonlocal_goto_save_area
,
1015 integer_one_node
, NULL_TREE
, NULL_TREE
);
1016 r_save
= expand_expr (t_save
, NULL_RTX
, VOIDmode
, EXPAND_WRITE
);
1018 emit_stack_save (SAVE_NONLOCAL
, &r_save
, NULL_RTX
);
1021 /* Return an rtx representing the address of an area of memory dynamically
1022 pushed on the stack. This region of memory is always aligned to
1023 a multiple of BIGGEST_ALIGNMENT.
1025 Any required stack pointer alignment is preserved.
1027 SIZE is an rtx representing the size of the area.
1028 TARGET is a place in which the address can be placed.
1030 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1033 allocate_dynamic_stack_space (rtx size
, rtx target
, int known_align
)
1035 /* If we're asking for zero bytes, it doesn't matter what we point
1036 to since we can't dereference it. But return a reasonable
1038 if (size
== const0_rtx
)
1039 return virtual_stack_dynamic_rtx
;
1041 /* Otherwise, show we're calling alloca or equivalent. */
1042 current_function_calls_alloca
= 1;
1044 /* Ensure the size is in the proper mode. */
1045 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1046 size
= convert_to_mode (Pmode
, size
, 1);
1048 /* We can't attempt to minimize alignment necessary, because we don't
1049 know the final value of preferred_stack_boundary yet while executing
1051 cfun
->preferred_stack_boundary
= PREFERRED_STACK_BOUNDARY
;
1053 /* We will need to ensure that the address we return is aligned to
1054 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1055 always know its final value at this point in the compilation (it
1056 might depend on the size of the outgoing parameter lists, for
1057 example), so we must align the value to be returned in that case.
1058 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1059 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1060 We must also do an alignment operation on the returned value if
1061 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1063 If we have to align, we must leave space in SIZE for the hole
1064 that might result from the alignment operation. */
1066 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1067 #define MUST_ALIGN 1
1069 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1074 = force_operand (plus_constant (size
,
1075 BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1078 #ifdef SETJMP_VIA_SAVE_AREA
1079 /* If setjmp restores regs from a save area in the stack frame,
1080 avoid clobbering the reg save area. Note that the offset of
1081 virtual_incoming_args_rtx includes the preallocated stack args space.
1082 It would be no problem to clobber that, but it's on the wrong side
1083 of the old save area.
1085 What used to happen is that, since we did not know for sure
1086 whether setjmp() was invoked until after RTL generation, we
1087 would use reg notes to store the "optimized" size and fix things
1088 up later. These days we know this information before we ever
1089 start building RTL so the reg notes are unnecessary. */
1090 if (!current_function_calls_setjmp
)
1092 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
1094 /* ??? Code below assumes that the save area needs maximal
1095 alignment. This constraint may be too strong. */
1096 gcc_assert (PREFERRED_STACK_BOUNDARY
== BIGGEST_ALIGNMENT
);
1098 if (GET_CODE (size
) == CONST_INT
)
1100 HOST_WIDE_INT
new = INTVAL (size
) / align
* align
;
1102 if (INTVAL (size
) != new)
1103 size
= GEN_INT (new);
1107 /* Since we know overflow is not possible, we avoid using
1108 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1109 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
,
1110 GEN_INT (align
), NULL_RTX
, 1);
1111 size
= expand_mult (Pmode
, size
,
1112 GEN_INT (align
), NULL_RTX
, 1);
1118 = expand_binop (Pmode
, sub_optab
, virtual_stack_dynamic_rtx
,
1119 stack_pointer_rtx
, NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1121 size
= expand_binop (Pmode
, add_optab
, size
, dynamic_offset
,
1122 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1124 #endif /* SETJMP_VIA_SAVE_AREA */
1126 /* Round the size to a multiple of the required stack alignment.
1127 Since the stack if presumed to be rounded before this allocation,
1128 this will maintain the required alignment.
1130 If the stack grows downward, we could save an insn by subtracting
1131 SIZE from the stack pointer and then aligning the stack pointer.
1132 The problem with this is that the stack pointer may be unaligned
1133 between the execution of the subtraction and alignment insns and
1134 some machines do not allow this. Even on those that do, some
1135 signal handlers malfunction if a signal should occur between those
1136 insns. Since this is an extremely rare event, we have no reliable
1137 way of knowing which systems have this problem. So we avoid even
1138 momentarily mis-aligning the stack. */
1140 /* If we added a variable amount to SIZE,
1141 we can no longer assume it is aligned. */
1142 #if !defined (SETJMP_VIA_SAVE_AREA)
1143 if (MUST_ALIGN
|| known_align
% PREFERRED_STACK_BOUNDARY
!= 0)
1145 size
= round_push (size
);
1147 do_pending_stack_adjust ();
1149 /* We ought to be called always on the toplevel and stack ought to be aligned
1151 gcc_assert (!(stack_pointer_delta
1152 % (PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
)));
1154 /* If needed, check that we have the required amount of stack. Take into
1155 account what has already been checked. */
1156 if (flag_stack_check
&& ! STACK_CHECK_BUILTIN
)
1157 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE
+ STACK_CHECK_PROTECT
, size
);
1159 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1160 if (target
== 0 || !REG_P (target
)
1161 || REGNO (target
) < FIRST_PSEUDO_REGISTER
1162 || GET_MODE (target
) != Pmode
)
1163 target
= gen_reg_rtx (Pmode
);
1165 mark_reg_pointer (target
, known_align
);
1167 /* Perform the required allocation from the stack. Some systems do
1168 this differently than simply incrementing/decrementing from the
1169 stack pointer, such as acquiring the space by calling malloc(). */
1170 #ifdef HAVE_allocate_stack
1171 if (HAVE_allocate_stack
)
1173 enum machine_mode mode
= STACK_SIZE_MODE
;
1174 insn_operand_predicate_fn pred
;
1176 /* We don't have to check against the predicate for operand 0 since
1177 TARGET is known to be a pseudo of the proper mode, which must
1178 be valid for the operand. For operand 1, convert to the
1179 proper mode and validate. */
1180 if (mode
== VOIDmode
)
1181 mode
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].mode
;
1183 pred
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].predicate
;
1184 if (pred
&& ! ((*pred
) (size
, mode
)))
1185 size
= copy_to_mode_reg (mode
, convert_to_mode (mode
, size
, 1));
1187 emit_insn (gen_allocate_stack (target
, size
));
1192 #ifndef STACK_GROWS_DOWNWARD
1193 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1196 /* Check stack bounds if necessary. */
1197 if (current_function_limit_stack
)
1200 rtx space_available
= gen_label_rtx ();
1201 #ifdef STACK_GROWS_DOWNWARD
1202 available
= expand_binop (Pmode
, sub_optab
,
1203 stack_pointer_rtx
, stack_limit_rtx
,
1204 NULL_RTX
, 1, OPTAB_WIDEN
);
1206 available
= expand_binop (Pmode
, sub_optab
,
1207 stack_limit_rtx
, stack_pointer_rtx
,
1208 NULL_RTX
, 1, OPTAB_WIDEN
);
1210 emit_cmp_and_jump_insns (available
, size
, GEU
, NULL_RTX
, Pmode
, 1,
1214 emit_insn (gen_trap ());
1217 error ("stack limits not supported on this target");
1219 emit_label (space_available
);
1222 anti_adjust_stack (size
);
1224 #ifdef STACK_GROWS_DOWNWARD
1225 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1231 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1232 but we know it can't. So add ourselves and then do
1234 target
= expand_binop (Pmode
, add_optab
, target
,
1235 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1236 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1237 target
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, target
,
1238 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1240 target
= expand_mult (Pmode
, target
,
1241 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1245 /* Record the new stack level for nonlocal gotos. */
1246 if (cfun
->nonlocal_goto_save_area
!= 0)
1247 update_nonlocal_goto_save_area ();
1252 /* A front end may want to override GCC's stack checking by providing a
1253 run-time routine to call to check the stack, so provide a mechanism for
1254 calling that routine. */
1256 static GTY(()) rtx stack_check_libfunc
;
1259 set_stack_check_libfunc (rtx libfunc
)
1261 stack_check_libfunc
= libfunc
;
1264 /* Emit one stack probe at ADDRESS, an address within the stack. */
1267 emit_stack_probe (rtx address
)
1269 rtx memref
= gen_rtx_MEM (word_mode
, address
);
1271 MEM_VOLATILE_P (memref
) = 1;
1273 if (STACK_CHECK_PROBE_LOAD
)
1274 emit_move_insn (gen_reg_rtx (word_mode
), memref
);
1276 emit_move_insn (memref
, const0_rtx
);
1279 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1280 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1281 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1282 subtract from the stack. If SIZE is constant, this is done
1283 with a fixed number of probes. Otherwise, we must make a loop. */
1285 #ifdef STACK_GROWS_DOWNWARD
1286 #define STACK_GROW_OP MINUS
1288 #define STACK_GROW_OP PLUS
1292 probe_stack_range (HOST_WIDE_INT first
, rtx size
)
1294 /* First ensure SIZE is Pmode. */
1295 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1296 size
= convert_to_mode (Pmode
, size
, 1);
1298 /* Next see if the front end has set up a function for us to call to
1300 if (stack_check_libfunc
!= 0)
1302 rtx addr
= memory_address (QImode
,
1303 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1305 plus_constant (size
, first
)));
1307 addr
= convert_memory_address (ptr_mode
, addr
);
1308 emit_library_call (stack_check_libfunc
, LCT_NORMAL
, VOIDmode
, 1, addr
,
1312 /* Next see if we have an insn to check the stack. Use it if so. */
1313 #ifdef HAVE_check_stack
1314 else if (HAVE_check_stack
)
1316 insn_operand_predicate_fn pred
;
1318 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1320 plus_constant (size
, first
)),
1323 pred
= insn_data
[(int) CODE_FOR_check_stack
].operand
[0].predicate
;
1324 if (pred
&& ! ((*pred
) (last_addr
, Pmode
)))
1325 last_addr
= copy_to_mode_reg (Pmode
, last_addr
);
1327 emit_insn (gen_check_stack (last_addr
));
1331 /* If we have to generate explicit probes, see if we have a constant
1332 small number of them to generate. If so, that's the easy case. */
1333 else if (GET_CODE (size
) == CONST_INT
1334 && INTVAL (size
) < 10 * STACK_CHECK_PROBE_INTERVAL
)
1336 HOST_WIDE_INT offset
;
1338 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1339 for values of N from 1 until it exceeds LAST. If only one
1340 probe is needed, this will not generate any code. Then probe
1342 for (offset
= first
+ STACK_CHECK_PROBE_INTERVAL
;
1343 offset
< INTVAL (size
);
1344 offset
= offset
+ STACK_CHECK_PROBE_INTERVAL
)
1345 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1349 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1351 plus_constant (size
, first
)));
1354 /* In the variable case, do the same as above, but in a loop. We emit loop
1355 notes so that loop optimization can be done. */
1359 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1361 GEN_INT (first
+ STACK_CHECK_PROBE_INTERVAL
)),
1364 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1366 plus_constant (size
, first
)),
1368 rtx incr
= GEN_INT (STACK_CHECK_PROBE_INTERVAL
);
1369 rtx loop_lab
= gen_label_rtx ();
1370 rtx test_lab
= gen_label_rtx ();
1371 rtx end_lab
= gen_label_rtx ();
1374 if (!REG_P (test_addr
)
1375 || REGNO (test_addr
) < FIRST_PSEUDO_REGISTER
)
1376 test_addr
= force_reg (Pmode
, test_addr
);
1378 emit_jump (test_lab
);
1380 emit_label (loop_lab
);
1381 emit_stack_probe (test_addr
);
1383 #ifdef STACK_GROWS_DOWNWARD
1384 #define CMP_OPCODE GTU
1385 temp
= expand_binop (Pmode
, sub_optab
, test_addr
, incr
, test_addr
,
1388 #define CMP_OPCODE LTU
1389 temp
= expand_binop (Pmode
, add_optab
, test_addr
, incr
, test_addr
,
1393 gcc_assert (temp
== test_addr
);
1395 emit_label (test_lab
);
1396 emit_cmp_and_jump_insns (test_addr
, last_addr
, CMP_OPCODE
,
1397 NULL_RTX
, Pmode
, 1, loop_lab
);
1398 emit_jump (end_lab
);
1399 emit_label (end_lab
);
1401 emit_stack_probe (last_addr
);
1405 /* Return an rtx representing the register or memory location
1406 in which a scalar value of data type VALTYPE
1407 was returned by a function call to function FUNC.
1408 FUNC is a FUNCTION_DECL node if the precise function is known,
1410 OUTGOING is 1 if on a machine with register windows this function
1411 should return the register in which the function will put its result
1415 hard_function_value (tree valtype
, tree func ATTRIBUTE_UNUSED
,
1416 int outgoing ATTRIBUTE_UNUSED
)
1420 #ifdef FUNCTION_OUTGOING_VALUE
1422 val
= FUNCTION_OUTGOING_VALUE (valtype
, func
);
1425 val
= FUNCTION_VALUE (valtype
, func
);
1428 && GET_MODE (val
) == BLKmode
)
1430 unsigned HOST_WIDE_INT bytes
= int_size_in_bytes (valtype
);
1431 enum machine_mode tmpmode
;
1433 /* int_size_in_bytes can return -1. We don't need a check here
1434 since the value of bytes will then be large enough that no
1435 mode will match anyway. */
1437 for (tmpmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
1438 tmpmode
!= VOIDmode
;
1439 tmpmode
= GET_MODE_WIDER_MODE (tmpmode
))
1441 /* Have we found a large enough mode? */
1442 if (GET_MODE_SIZE (tmpmode
) >= bytes
)
1446 /* No suitable mode found. */
1447 gcc_assert (tmpmode
!= VOIDmode
);
1449 PUT_MODE (val
, tmpmode
);
1454 /* Return an rtx representing the register or memory location
1455 in which a scalar value of mode MODE was returned by a library call. */
1458 hard_libcall_value (enum machine_mode mode
)
1460 return LIBCALL_VALUE (mode
);
1463 /* Look up the tree code for a given rtx code
1464 to provide the arithmetic operation for REAL_ARITHMETIC.
1465 The function returns an int because the caller may not know
1466 what `enum tree_code' means. */
1469 rtx_to_tree_code (enum rtx_code code
)
1471 enum tree_code tcode
;
1494 tcode
= LAST_AND_UNUSED_TREE_CODE
;
1497 return ((int) tcode
);
1500 #include "gt-explow.h"