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"
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
= simplify_gen_binary (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
))
445 /* Perform machine-dependent transformations on X
446 in certain cases. This is not necessary since the code
447 below can handle all possible cases, but machine-dependent
448 transformations can make better code. */
449 LEGITIMIZE_ADDRESS (x
, oldx
, mode
, done
);
451 /* PLUS and MULT can appear in special ways
452 as the result of attempts to make an address usable for indexing.
453 Usually they are dealt with by calling force_operand, below.
454 But a sum containing constant terms is special
455 if removing them makes the sum a valid address:
456 then we generate that address in a register
457 and index off of it. We do this because it often makes
458 shorter code, and because the addresses thus generated
459 in registers often become common subexpressions. */
460 if (GET_CODE (x
) == PLUS
)
462 rtx constant_term
= const0_rtx
;
463 rtx y
= eliminate_constant_term (x
, &constant_term
);
464 if (constant_term
== const0_rtx
465 || ! memory_address_p (mode
, y
))
466 x
= force_operand (x
, NULL_RTX
);
469 y
= gen_rtx_PLUS (GET_MODE (x
), copy_to_reg (y
), constant_term
);
470 if (! memory_address_p (mode
, y
))
471 x
= force_operand (x
, NULL_RTX
);
477 else if (GET_CODE (x
) == MULT
|| GET_CODE (x
) == MINUS
)
478 x
= force_operand (x
, NULL_RTX
);
480 /* If we have a register that's an invalid address,
481 it must be a hard reg of the wrong class. Copy it to a pseudo. */
485 /* Last resort: copy the value to a register, since
486 the register is a valid address. */
488 x
= force_reg (Pmode
, x
);
493 gcc_assert (memory_address_p (mode
, x
));
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 /* Convert a mem ref into one with a valid memory address.
513 Pass through anything else unchanged. */
516 validize_mem (rtx ref
)
520 ref
= use_anchored_address (ref
);
521 if (memory_address_p (GET_MODE (ref
), XEXP (ref
, 0)))
524 /* Don't alter REF itself, since that is probably a stack slot. */
525 return replace_equiv_address (ref
, XEXP (ref
, 0));
528 /* If X is a memory reference to a member of an object block, try rewriting
529 it to use an anchor instead. Return the new memory reference on success
530 and the old one on failure. */
533 use_anchored_address (rtx x
)
536 HOST_WIDE_INT offset
;
538 if (!flag_section_anchors
)
544 /* Split the address into a base and offset. */
547 if (GET_CODE (base
) == CONST
548 && GET_CODE (XEXP (base
, 0)) == PLUS
549 && GET_CODE (XEXP (XEXP (base
, 0), 1)) == CONST_INT
)
551 offset
+= INTVAL (XEXP (XEXP (base
, 0), 1));
552 base
= XEXP (XEXP (base
, 0), 0);
555 /* Check whether BASE is suitable for anchors. */
556 if (GET_CODE (base
) != SYMBOL_REF
557 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base
)
558 || SYMBOL_REF_ANCHOR_P (base
)
559 || SYMBOL_REF_BLOCK (base
) == NULL
560 || !targetm
.use_anchors_for_symbol_p (base
))
563 /* Decide where BASE is going to be. */
564 place_block_symbol (base
);
566 /* Get the anchor we need to use. */
567 offset
+= SYMBOL_REF_BLOCK_OFFSET (base
);
568 base
= get_section_anchor (SYMBOL_REF_BLOCK (base
), offset
,
569 SYMBOL_REF_TLS_MODEL (base
));
571 /* Work out the offset from the anchor. */
572 offset
-= SYMBOL_REF_BLOCK_OFFSET (base
);
574 /* If we're going to run a CSE pass, force the anchor into a register.
575 We will then be able to reuse registers for several accesses, if the
576 target costs say that that's worthwhile. */
577 if (!cse_not_expected
)
578 base
= force_reg (GET_MODE (base
), base
);
580 return replace_equiv_address (x
, plus_constant (base
, offset
));
583 /* Copy the value or contents of X to a new temp reg and return that reg. */
588 rtx temp
= gen_reg_rtx (GET_MODE (x
));
590 /* If not an operand, must be an address with PLUS and MULT so
591 do the computation. */
592 if (! general_operand (x
, VOIDmode
))
593 x
= force_operand (x
, temp
);
596 emit_move_insn (temp
, x
);
601 /* Like copy_to_reg but always give the new register mode Pmode
602 in case X is a constant. */
605 copy_addr_to_reg (rtx x
)
607 return copy_to_mode_reg (Pmode
, x
);
610 /* Like copy_to_reg but always give the new register mode MODE
611 in case X is a constant. */
614 copy_to_mode_reg (enum machine_mode mode
, rtx x
)
616 rtx temp
= gen_reg_rtx (mode
);
618 /* If not an operand, must be an address with PLUS and MULT so
619 do the computation. */
620 if (! general_operand (x
, VOIDmode
))
621 x
= force_operand (x
, temp
);
623 gcc_assert (GET_MODE (x
) == mode
|| GET_MODE (x
) == VOIDmode
);
625 emit_move_insn (temp
, x
);
629 /* Load X into a register if it is not already one.
630 Use mode MODE for the register.
631 X should be valid for mode MODE, but it may be a constant which
632 is valid for all integer modes; that's why caller must specify MODE.
634 The caller must not alter the value in the register we return,
635 since we mark it as a "constant" register. */
638 force_reg (enum machine_mode mode
, rtx x
)
645 if (general_operand (x
, mode
))
647 temp
= gen_reg_rtx (mode
);
648 insn
= emit_move_insn (temp
, x
);
652 temp
= force_operand (x
, NULL_RTX
);
654 insn
= get_last_insn ();
657 rtx temp2
= gen_reg_rtx (mode
);
658 insn
= emit_move_insn (temp2
, temp
);
663 /* Let optimizers know that TEMP's value never changes
664 and that X can be substituted for it. Don't get confused
665 if INSN set something else (such as a SUBREG of TEMP). */
667 && (set
= single_set (insn
)) != 0
668 && SET_DEST (set
) == temp
669 && ! rtx_equal_p (x
, SET_SRC (set
)))
670 set_unique_reg_note (insn
, REG_EQUAL
, x
);
672 /* Let optimizers know that TEMP is a pointer, and if so, the
673 known alignment of that pointer. */
676 if (GET_CODE (x
) == SYMBOL_REF
)
678 align
= BITS_PER_UNIT
;
679 if (SYMBOL_REF_DECL (x
) && DECL_P (SYMBOL_REF_DECL (x
)))
680 align
= DECL_ALIGN (SYMBOL_REF_DECL (x
));
682 else if (GET_CODE (x
) == LABEL_REF
)
683 align
= BITS_PER_UNIT
;
684 else if (GET_CODE (x
) == CONST
685 && GET_CODE (XEXP (x
, 0)) == PLUS
686 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == SYMBOL_REF
687 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
)
689 rtx s
= XEXP (XEXP (x
, 0), 0);
690 rtx c
= XEXP (XEXP (x
, 0), 1);
694 if (SYMBOL_REF_DECL (s
) && DECL_P (SYMBOL_REF_DECL (s
)))
695 sa
= DECL_ALIGN (SYMBOL_REF_DECL (s
));
697 ca
= exact_log2 (INTVAL (c
) & -INTVAL (c
)) * BITS_PER_UNIT
;
699 align
= MIN (sa
, ca
);
702 if (align
|| (MEM_P (x
) && MEM_POINTER (x
)))
703 mark_reg_pointer (temp
, align
);
709 /* If X is a memory ref, copy its contents to a new temp reg and return
710 that reg. Otherwise, return X. */
713 force_not_mem (rtx x
)
717 if (!MEM_P (x
) || GET_MODE (x
) == BLKmode
)
720 temp
= gen_reg_rtx (GET_MODE (x
));
723 REG_POINTER (temp
) = 1;
725 emit_move_insn (temp
, x
);
729 /* Copy X to TARGET (if it's nonzero and a reg)
730 or to a new temp reg and return that reg.
731 MODE is the mode to use for X in case it is a constant. */
734 copy_to_suggested_reg (rtx x
, rtx target
, enum machine_mode mode
)
738 if (target
&& REG_P (target
))
741 temp
= gen_reg_rtx (mode
);
743 emit_move_insn (temp
, x
);
747 /* Return the mode to use to store a scalar of TYPE and MODE.
748 PUNSIGNEDP points to the signedness of the type and may be adjusted
749 to show what signedness to use on extension operations.
751 FOR_CALL is nonzero if this call is promoting args for a call. */
753 #if defined(PROMOTE_MODE) && !defined(PROMOTE_FUNCTION_MODE)
754 #define PROMOTE_FUNCTION_MODE PROMOTE_MODE
758 promote_mode (const_tree type
, enum machine_mode mode
, int *punsignedp
,
759 int for_call ATTRIBUTE_UNUSED
)
761 const enum tree_code code
= TREE_CODE (type
);
762 int unsignedp
= *punsignedp
;
771 #ifdef PROMOTE_FUNCTION_MODE
772 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
773 case REAL_TYPE
: case OFFSET_TYPE
: case FIXED_POINT_TYPE
:
778 PROMOTE_FUNCTION_MODE (mode
, unsignedp
, type
);
783 PROMOTE_MODE (mode
, unsignedp
, type
);
789 #ifdef POINTERS_EXTEND_UNSIGNED
793 unsignedp
= POINTERS_EXTEND_UNSIGNED
;
801 *punsignedp
= unsignedp
;
805 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
806 This pops when ADJUST is positive. ADJUST need not be constant. */
809 adjust_stack (rtx adjust
)
813 if (adjust
== const0_rtx
)
816 /* We expect all variable sized adjustments to be multiple of
817 PREFERRED_STACK_BOUNDARY. */
818 if (GET_CODE (adjust
) == CONST_INT
)
819 stack_pointer_delta
-= INTVAL (adjust
);
821 temp
= expand_binop (Pmode
,
822 #ifdef STACK_GROWS_DOWNWARD
827 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
830 if (temp
!= stack_pointer_rtx
)
831 emit_move_insn (stack_pointer_rtx
, temp
);
834 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
835 This pushes when ADJUST is positive. ADJUST need not be constant. */
838 anti_adjust_stack (rtx adjust
)
842 if (adjust
== const0_rtx
)
845 /* We expect all variable sized adjustments to be multiple of
846 PREFERRED_STACK_BOUNDARY. */
847 if (GET_CODE (adjust
) == CONST_INT
)
848 stack_pointer_delta
+= INTVAL (adjust
);
850 temp
= expand_binop (Pmode
,
851 #ifdef STACK_GROWS_DOWNWARD
856 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
859 if (temp
!= stack_pointer_rtx
)
860 emit_move_insn (stack_pointer_rtx
, temp
);
863 /* Round the size of a block to be pushed up to the boundary required
864 by this machine. SIZE is the desired size, which need not be constant. */
867 round_push (rtx size
)
869 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
874 if (GET_CODE (size
) == CONST_INT
)
876 HOST_WIDE_INT new_size
= (INTVAL (size
) + align
- 1) / align
* align
;
878 if (INTVAL (size
) != new_size
)
879 size
= GEN_INT (new_size
);
883 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
884 but we know it can't. So add ourselves and then do
886 size
= expand_binop (Pmode
, add_optab
, size
, GEN_INT (align
- 1),
887 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
888 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
, GEN_INT (align
),
890 size
= expand_mult (Pmode
, size
, GEN_INT (align
), NULL_RTX
, 1);
896 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
897 to a previously-created save area. If no save area has been allocated,
898 this function will allocate one. If a save area is specified, it
899 must be of the proper mode.
901 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
902 are emitted at the current position. */
905 emit_stack_save (enum save_level save_level
, rtx
*psave
, rtx after
)
908 /* The default is that we use a move insn and save in a Pmode object. */
909 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
910 enum machine_mode mode
= STACK_SAVEAREA_MODE (save_level
);
912 /* See if this machine has anything special to do for this kind of save. */
915 #ifdef HAVE_save_stack_block
917 if (HAVE_save_stack_block
)
918 fcn
= gen_save_stack_block
;
921 #ifdef HAVE_save_stack_function
923 if (HAVE_save_stack_function
)
924 fcn
= gen_save_stack_function
;
927 #ifdef HAVE_save_stack_nonlocal
929 if (HAVE_save_stack_nonlocal
)
930 fcn
= gen_save_stack_nonlocal
;
937 /* If there is no save area and we have to allocate one, do so. Otherwise
938 verify the save area is the proper mode. */
942 if (mode
!= VOIDmode
)
944 if (save_level
== SAVE_NONLOCAL
)
945 *psave
= sa
= assign_stack_local (mode
, GET_MODE_SIZE (mode
), 0);
947 *psave
= sa
= gen_reg_rtx (mode
);
956 do_pending_stack_adjust ();
957 /* We must validize inside the sequence, to ensure that any instructions
958 created by the validize call also get moved to the right place. */
960 sa
= validize_mem (sa
);
961 emit_insn (fcn (sa
, stack_pointer_rtx
));
964 emit_insn_after (seq
, after
);
968 do_pending_stack_adjust ();
970 sa
= validize_mem (sa
);
971 emit_insn (fcn (sa
, stack_pointer_rtx
));
975 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
976 area made by emit_stack_save. If it is zero, we have nothing to do.
978 Put any emitted insns after insn AFTER, if nonzero, otherwise at
982 emit_stack_restore (enum save_level save_level
, rtx sa
, rtx after
)
984 /* The default is that we use a move insn. */
985 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
987 /* See if this machine has anything special to do for this kind of save. */
990 #ifdef HAVE_restore_stack_block
992 if (HAVE_restore_stack_block
)
993 fcn
= gen_restore_stack_block
;
996 #ifdef HAVE_restore_stack_function
998 if (HAVE_restore_stack_function
)
999 fcn
= gen_restore_stack_function
;
1002 #ifdef HAVE_restore_stack_nonlocal
1004 if (HAVE_restore_stack_nonlocal
)
1005 fcn
= gen_restore_stack_nonlocal
;
1014 sa
= validize_mem (sa
);
1015 /* These clobbers prevent the scheduler from moving
1016 references to variable arrays below the code
1017 that deletes (pops) the arrays. */
1018 emit_clobber (gen_rtx_MEM (BLKmode
, gen_rtx_SCRATCH (VOIDmode
)));
1019 emit_clobber (gen_rtx_MEM (BLKmode
, stack_pointer_rtx
));
1022 discard_pending_stack_adjust ();
1029 emit_insn (fcn (stack_pointer_rtx
, sa
));
1032 emit_insn_after (seq
, after
);
1035 emit_insn (fcn (stack_pointer_rtx
, sa
));
1038 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1039 function. This function should be called whenever we allocate or
1040 deallocate dynamic stack space. */
1043 update_nonlocal_goto_save_area (void)
1048 /* The nonlocal_goto_save_area object is an array of N pointers. The
1049 first one is used for the frame pointer save; the rest are sized by
1050 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1051 of the stack save area slots. */
1052 t_save
= build4 (ARRAY_REF
, ptr_type_node
, cfun
->nonlocal_goto_save_area
,
1053 integer_one_node
, NULL_TREE
, NULL_TREE
);
1054 r_save
= expand_expr (t_save
, NULL_RTX
, VOIDmode
, EXPAND_WRITE
);
1056 emit_stack_save (SAVE_NONLOCAL
, &r_save
, NULL_RTX
);
1059 /* Return an rtx representing the address of an area of memory dynamically
1060 pushed on the stack. This region of memory is always aligned to
1061 a multiple of BIGGEST_ALIGNMENT.
1063 Any required stack pointer alignment is preserved.
1065 SIZE is an rtx representing the size of the area.
1066 TARGET is a place in which the address can be placed.
1068 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1071 allocate_dynamic_stack_space (rtx size
, rtx target
, int known_align
)
1073 /* If we're asking for zero bytes, it doesn't matter what we point
1074 to since we can't dereference it. But return a reasonable
1076 if (size
== const0_rtx
)
1077 return virtual_stack_dynamic_rtx
;
1079 /* Otherwise, show we're calling alloca or equivalent. */
1080 cfun
->calls_alloca
= 1;
1082 /* Ensure the size is in the proper mode. */
1083 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1084 size
= convert_to_mode (Pmode
, size
, 1);
1086 /* We can't attempt to minimize alignment necessary, because we don't
1087 know the final value of preferred_stack_boundary yet while executing
1089 crtl
->preferred_stack_boundary
= PREFERRED_STACK_BOUNDARY
;
1091 /* We will need to ensure that the address we return is aligned to
1092 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1093 always know its final value at this point in the compilation (it
1094 might depend on the size of the outgoing parameter lists, for
1095 example), so we must align the value to be returned in that case.
1096 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1097 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1098 We must also do an alignment operation on the returned value if
1099 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1101 If we have to align, we must leave space in SIZE for the hole
1102 that might result from the alignment operation. */
1104 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1105 #define MUST_ALIGN 1
1107 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1112 = force_operand (plus_constant (size
,
1113 BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1116 #ifdef SETJMP_VIA_SAVE_AREA
1117 /* If setjmp restores regs from a save area in the stack frame,
1118 avoid clobbering the reg save area. Note that the offset of
1119 virtual_incoming_args_rtx includes the preallocated stack args space.
1120 It would be no problem to clobber that, but it's on the wrong side
1121 of the old save area.
1123 What used to happen is that, since we did not know for sure
1124 whether setjmp() was invoked until after RTL generation, we
1125 would use reg notes to store the "optimized" size and fix things
1126 up later. These days we know this information before we ever
1127 start building RTL so the reg notes are unnecessary. */
1128 if (!cfun
->calls_setjmp
)
1130 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
1132 /* ??? Code below assumes that the save area needs maximal
1133 alignment. This constraint may be too strong. */
1134 gcc_assert (PREFERRED_STACK_BOUNDARY
== BIGGEST_ALIGNMENT
);
1136 if (GET_CODE (size
) == CONST_INT
)
1138 HOST_WIDE_INT new_size
= INTVAL (size
) / align
* align
;
1140 if (INTVAL (size
) != new_size
)
1141 size
= GEN_INT (new_size
);
1145 /* Since we know overflow is not possible, we avoid using
1146 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1147 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
,
1148 GEN_INT (align
), NULL_RTX
, 1);
1149 size
= expand_mult (Pmode
, size
,
1150 GEN_INT (align
), NULL_RTX
, 1);
1156 = expand_binop (Pmode
, sub_optab
, virtual_stack_dynamic_rtx
,
1157 stack_pointer_rtx
, NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1159 size
= expand_binop (Pmode
, add_optab
, size
, dynamic_offset
,
1160 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1162 #endif /* SETJMP_VIA_SAVE_AREA */
1164 /* Round the size to a multiple of the required stack alignment.
1165 Since the stack if presumed to be rounded before this allocation,
1166 this will maintain the required alignment.
1168 If the stack grows downward, we could save an insn by subtracting
1169 SIZE from the stack pointer and then aligning the stack pointer.
1170 The problem with this is that the stack pointer may be unaligned
1171 between the execution of the subtraction and alignment insns and
1172 some machines do not allow this. Even on those that do, some
1173 signal handlers malfunction if a signal should occur between those
1174 insns. Since this is an extremely rare event, we have no reliable
1175 way of knowing which systems have this problem. So we avoid even
1176 momentarily mis-aligning the stack. */
1178 /* If we added a variable amount to SIZE,
1179 we can no longer assume it is aligned. */
1180 #if !defined (SETJMP_VIA_SAVE_AREA)
1181 if (MUST_ALIGN
|| known_align
% PREFERRED_STACK_BOUNDARY
!= 0)
1183 size
= round_push (size
);
1185 do_pending_stack_adjust ();
1187 /* We ought to be called always on the toplevel and stack ought to be aligned
1189 gcc_assert (!(stack_pointer_delta
1190 % (PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
)));
1192 /* If needed, check that we have the required amount of stack.
1193 Take into account what has already been checked. */
1194 if (flag_stack_check
== GENERIC_STACK_CHECK
)
1195 probe_stack_range (STACK_OLD_CHECK_PROTECT
+ STACK_CHECK_MAX_FRAME_SIZE
,
1197 else if (flag_stack_check
== STATIC_BUILTIN_STACK_CHECK
)
1198 probe_stack_range (STACK_CHECK_PROTECT
, size
);
1200 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1201 if (target
== 0 || !REG_P (target
)
1202 || REGNO (target
) < FIRST_PSEUDO_REGISTER
1203 || GET_MODE (target
) != Pmode
)
1204 target
= gen_reg_rtx (Pmode
);
1206 mark_reg_pointer (target
, known_align
);
1208 /* Perform the required allocation from the stack. Some systems do
1209 this differently than simply incrementing/decrementing from the
1210 stack pointer, such as acquiring the space by calling malloc(). */
1211 #ifdef HAVE_allocate_stack
1212 if (HAVE_allocate_stack
)
1214 enum machine_mode mode
= STACK_SIZE_MODE
;
1215 insn_operand_predicate_fn pred
;
1217 /* We don't have to check against the predicate for operand 0 since
1218 TARGET is known to be a pseudo of the proper mode, which must
1219 be valid for the operand. For operand 1, convert to the
1220 proper mode and validate. */
1221 if (mode
== VOIDmode
)
1222 mode
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].mode
;
1224 pred
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].predicate
;
1225 if (pred
&& ! ((*pred
) (size
, mode
)))
1226 size
= copy_to_mode_reg (mode
, convert_to_mode (mode
, size
, 1));
1228 emit_insn (gen_allocate_stack (target
, size
));
1233 #ifndef STACK_GROWS_DOWNWARD
1234 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1237 /* Check stack bounds if necessary. */
1238 if (crtl
->limit_stack
)
1241 rtx space_available
= gen_label_rtx ();
1242 #ifdef STACK_GROWS_DOWNWARD
1243 available
= expand_binop (Pmode
, sub_optab
,
1244 stack_pointer_rtx
, stack_limit_rtx
,
1245 NULL_RTX
, 1, OPTAB_WIDEN
);
1247 available
= expand_binop (Pmode
, sub_optab
,
1248 stack_limit_rtx
, stack_pointer_rtx
,
1249 NULL_RTX
, 1, OPTAB_WIDEN
);
1251 emit_cmp_and_jump_insns (available
, size
, GEU
, NULL_RTX
, Pmode
, 1,
1255 emit_insn (gen_trap ());
1258 error ("stack limits not supported on this target");
1260 emit_label (space_available
);
1263 anti_adjust_stack (size
);
1265 #ifdef STACK_GROWS_DOWNWARD
1266 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1272 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1273 but we know it can't. So add ourselves and then do
1275 target
= expand_binop (Pmode
, add_optab
, target
,
1276 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1277 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1278 target
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, target
,
1279 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1281 target
= expand_mult (Pmode
, target
,
1282 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1286 /* Record the new stack level for nonlocal gotos. */
1287 if (cfun
->nonlocal_goto_save_area
!= 0)
1288 update_nonlocal_goto_save_area ();
1293 /* A front end may want to override GCC's stack checking by providing a
1294 run-time routine to call to check the stack, so provide a mechanism for
1295 calling that routine. */
1297 static GTY(()) rtx stack_check_libfunc
;
1300 set_stack_check_libfunc (rtx libfunc
)
1302 stack_check_libfunc
= libfunc
;
1305 /* Emit one stack probe at ADDRESS, an address within the stack. */
1308 emit_stack_probe (rtx address
)
1310 rtx memref
= gen_rtx_MEM (word_mode
, address
);
1312 MEM_VOLATILE_P (memref
) = 1;
1314 if (STACK_CHECK_PROBE_LOAD
)
1315 emit_move_insn (gen_reg_rtx (word_mode
), memref
);
1317 emit_move_insn (memref
, const0_rtx
);
1320 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1321 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1322 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1323 subtract from the stack. If SIZE is constant, this is done
1324 with a fixed number of probes. Otherwise, we must make a loop. */
1326 #ifdef STACK_GROWS_DOWNWARD
1327 #define STACK_GROW_OP MINUS
1329 #define STACK_GROW_OP PLUS
1333 probe_stack_range (HOST_WIDE_INT first
, rtx size
)
1335 /* First ensure SIZE is Pmode. */
1336 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1337 size
= convert_to_mode (Pmode
, size
, 1);
1339 /* Next see if the front end has set up a function for us to call to
1341 if (stack_check_libfunc
!= 0)
1343 rtx addr
= memory_address (QImode
,
1344 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1346 plus_constant (size
, first
)));
1348 addr
= convert_memory_address (ptr_mode
, addr
);
1349 emit_library_call (stack_check_libfunc
, LCT_NORMAL
, VOIDmode
, 1, addr
,
1353 /* Next see if we have an insn to check the stack. Use it if so. */
1354 #ifdef HAVE_check_stack
1355 else if (HAVE_check_stack
)
1357 insn_operand_predicate_fn pred
;
1359 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1361 plus_constant (size
, first
)),
1364 pred
= insn_data
[(int) CODE_FOR_check_stack
].operand
[0].predicate
;
1365 if (pred
&& ! ((*pred
) (last_addr
, Pmode
)))
1366 last_addr
= copy_to_mode_reg (Pmode
, last_addr
);
1368 emit_insn (gen_check_stack (last_addr
));
1372 /* If we have to generate explicit probes, see if we have a constant
1373 small number of them to generate. If so, that's the easy case. */
1374 else if (GET_CODE (size
) == CONST_INT
1375 && INTVAL (size
) < 10 * STACK_CHECK_PROBE_INTERVAL
)
1377 HOST_WIDE_INT offset
;
1379 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1380 for values of N from 1 until it exceeds LAST. If only one
1381 probe is needed, this will not generate any code. Then probe
1383 for (offset
= first
+ STACK_CHECK_PROBE_INTERVAL
;
1384 offset
< INTVAL (size
);
1385 offset
= offset
+ STACK_CHECK_PROBE_INTERVAL
)
1386 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1390 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1392 plus_constant (size
, first
)));
1395 /* In the variable case, do the same as above, but in a loop. We emit loop
1396 notes so that loop optimization can be done. */
1400 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1402 GEN_INT (first
+ STACK_CHECK_PROBE_INTERVAL
)),
1405 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1407 plus_constant (size
, first
)),
1409 rtx incr
= GEN_INT (STACK_CHECK_PROBE_INTERVAL
);
1410 rtx loop_lab
= gen_label_rtx ();
1411 rtx test_lab
= gen_label_rtx ();
1412 rtx end_lab
= gen_label_rtx ();
1415 if (!REG_P (test_addr
)
1416 || REGNO (test_addr
) < FIRST_PSEUDO_REGISTER
)
1417 test_addr
= force_reg (Pmode
, test_addr
);
1419 emit_jump (test_lab
);
1421 emit_label (loop_lab
);
1422 emit_stack_probe (test_addr
);
1424 #ifdef STACK_GROWS_DOWNWARD
1425 #define CMP_OPCODE GTU
1426 temp
= expand_binop (Pmode
, sub_optab
, test_addr
, incr
, test_addr
,
1429 #define CMP_OPCODE LTU
1430 temp
= expand_binop (Pmode
, add_optab
, test_addr
, incr
, test_addr
,
1434 gcc_assert (temp
== test_addr
);
1436 emit_label (test_lab
);
1437 emit_cmp_and_jump_insns (test_addr
, last_addr
, CMP_OPCODE
,
1438 NULL_RTX
, Pmode
, 1, loop_lab
);
1439 emit_jump (end_lab
);
1440 emit_label (end_lab
);
1442 emit_stack_probe (last_addr
);
1446 /* Return an rtx representing the register or memory location
1447 in which a scalar value of data type VALTYPE
1448 was returned by a function call to function FUNC.
1449 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1450 function is known, otherwise 0.
1451 OUTGOING is 1 if on a machine with register windows this function
1452 should return the register in which the function will put its result
1456 hard_function_value (const_tree valtype
, const_tree func
, const_tree fntype
,
1457 int outgoing ATTRIBUTE_UNUSED
)
1461 val
= targetm
.calls
.function_value (valtype
, func
? func
: fntype
, outgoing
);
1464 && GET_MODE (val
) == BLKmode
)
1466 unsigned HOST_WIDE_INT bytes
= int_size_in_bytes (valtype
);
1467 enum machine_mode tmpmode
;
1469 /* int_size_in_bytes can return -1. We don't need a check here
1470 since the value of bytes will then be large enough that no
1471 mode will match anyway. */
1473 for (tmpmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
1474 tmpmode
!= VOIDmode
;
1475 tmpmode
= GET_MODE_WIDER_MODE (tmpmode
))
1477 /* Have we found a large enough mode? */
1478 if (GET_MODE_SIZE (tmpmode
) >= bytes
)
1482 /* No suitable mode found. */
1483 gcc_assert (tmpmode
!= VOIDmode
);
1485 PUT_MODE (val
, tmpmode
);
1490 /* Return an rtx representing the register or memory location
1491 in which a scalar value of mode MODE was returned by a library call. */
1494 hard_libcall_value (enum machine_mode mode
)
1496 return LIBCALL_VALUE (mode
);
1499 /* Look up the tree code for a given rtx code
1500 to provide the arithmetic operation for REAL_ARITHMETIC.
1501 The function returns an int because the caller may not know
1502 what `enum tree_code' means. */
1505 rtx_to_tree_code (enum rtx_code code
)
1507 enum tree_code tcode
;
1530 tcode
= LAST_AND_UNUSED_TREE_CODE
;
1533 return ((int) tcode
);
1536 #include "gt-explow.h"