1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
25 #include "diagnostic-core.h"
28 #include "stor-layout.h"
36 #include "hard-reg-set.h"
37 #include "insn-config.h"
40 #include "langhooks.h"
42 #include "common/common-target.h"
45 static rtx
break_out_memory_refs (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_PRECISION (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, given that X has
77 mode MODE. INPLACE is true if X can be modified inplace or false
78 if it must be treated as immutable. */
81 plus_constant (enum machine_mode mode
, rtx x
, HOST_WIDE_INT c
,
89 gcc_assert (GET_MODE (x
) == VOIDmode
|| GET_MODE (x
) == mode
);
101 CASE_CONST_SCALAR_INT
:
102 return immed_wide_int_const (wi::add (std::make_pair (x
, mode
), c
),
105 /* If this is a reference to the constant pool, try replacing it with
106 a reference to a new constant. If the resulting address isn't
107 valid, don't return it because we have no way to validize it. */
108 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
109 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
111 tem
= plus_constant (mode
, get_pool_constant (XEXP (x
, 0)), c
);
112 tem
= force_const_mem (GET_MODE (x
), tem
);
113 if (memory_address_p (GET_MODE (tem
), XEXP (tem
, 0)))
119 /* If adding to something entirely constant, set a flag
120 so that we can add a CONST around the result. */
121 if (inplace
&& shared_const_p (x
))
133 /* The interesting case is adding the integer to a sum. Look
134 for constant term in the sum and combine with C. For an
135 integer constant term or a constant term that is not an
136 explicit integer, we combine or group them together anyway.
138 We may not immediately return from the recursive call here, lest
139 all_constant gets lost. */
141 if (CONSTANT_P (XEXP (x
, 1)))
143 rtx term
= plus_constant (mode
, XEXP (x
, 1), c
, inplace
);
144 if (term
== const0_rtx
)
149 x
= gen_rtx_PLUS (mode
, XEXP (x
, 0), term
);
152 else if (rtx
*const_loc
= find_constant_term_loc (&y
))
156 /* We need to be careful since X may be shared and we can't
157 modify it in place. */
159 const_loc
= find_constant_term_loc (&x
);
161 *const_loc
= plus_constant (mode
, *const_loc
, c
, true);
171 x
= gen_rtx_PLUS (mode
, x
, gen_int_mode (c
, mode
));
173 if (GET_CODE (x
) == SYMBOL_REF
|| GET_CODE (x
) == LABEL_REF
)
175 else if (all_constant
)
176 return gen_rtx_CONST (mode
, x
);
181 /* If X is a sum, return a new sum like X but lacking any constant terms.
182 Add all the removed constant terms into *CONSTPTR.
183 X itself is not altered. The result != X if and only if
184 it is not isomorphic to X. */
187 eliminate_constant_term (rtx x
, rtx
*constptr
)
192 if (GET_CODE (x
) != PLUS
)
195 /* First handle constants appearing at this level explicitly. */
196 if (CONST_INT_P (XEXP (x
, 1))
197 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
), *constptr
,
199 && CONST_INT_P (tem
))
202 return eliminate_constant_term (XEXP (x
, 0), constptr
);
206 x0
= eliminate_constant_term (XEXP (x
, 0), &tem
);
207 x1
= eliminate_constant_term (XEXP (x
, 1), &tem
);
208 if ((x1
!= XEXP (x
, 1) || x0
!= XEXP (x
, 0))
209 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
),
211 && CONST_INT_P (tem
))
214 return gen_rtx_PLUS (GET_MODE (x
), x0
, x1
);
220 /* Returns a tree for the size of EXP in bytes. */
223 tree_expr_size (const_tree exp
)
226 && DECL_SIZE_UNIT (exp
) != 0)
227 return DECL_SIZE_UNIT (exp
);
229 return size_in_bytes (TREE_TYPE (exp
));
232 /* Return an rtx for the size in bytes of the value of EXP. */
239 if (TREE_CODE (exp
) == WITH_SIZE_EXPR
)
240 size
= TREE_OPERAND (exp
, 1);
243 size
= tree_expr_size (exp
);
245 gcc_assert (size
== SUBSTITUTE_PLACEHOLDER_IN_EXPR (size
, exp
));
248 return expand_expr (size
, NULL_RTX
, TYPE_MODE (sizetype
), EXPAND_NORMAL
);
251 /* Return a wide integer for the size in bytes of the value of EXP, or -1
252 if the size can vary or is larger than an integer. */
255 int_expr_size (tree exp
)
259 if (TREE_CODE (exp
) == WITH_SIZE_EXPR
)
260 size
= TREE_OPERAND (exp
, 1);
263 size
= tree_expr_size (exp
);
267 if (size
== 0 || !tree_fits_shwi_p (size
))
270 return tree_to_shwi (size
);
273 /* Return a copy of X in which all memory references
274 and all constants that involve symbol refs
275 have been replaced with new temporary registers.
276 Also emit code to load the memory locations and constants
277 into those registers.
279 If X contains no such constants or memory references,
280 X itself (not a copy) is returned.
282 If a constant is found in the address that is not a legitimate constant
283 in an insn, it is left alone in the hope that it might be valid in the
286 X may contain no arithmetic except addition, subtraction and multiplication.
287 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
290 break_out_memory_refs (rtx x
)
293 || (CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
)
294 && GET_MODE (x
) != VOIDmode
))
295 x
= force_reg (GET_MODE (x
), x
);
296 else if (GET_CODE (x
) == PLUS
|| GET_CODE (x
) == MINUS
297 || GET_CODE (x
) == MULT
)
299 rtx op0
= break_out_memory_refs (XEXP (x
, 0));
300 rtx op1
= break_out_memory_refs (XEXP (x
, 1));
302 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
303 x
= simplify_gen_binary (GET_CODE (x
), GET_MODE (x
), op0
, op1
);
309 /* Given X, a memory address in address space AS' pointer mode, convert it to
310 an address in the address space's address mode, or vice versa (TO_MODE says
311 which way). We take advantage of the fact that pointers are not allowed to
312 overflow by commuting arithmetic operations over conversions so that address
313 arithmetic insns can be used. IN_CONST is true if this conversion is inside
317 convert_memory_address_addr_space_1 (enum machine_mode to_mode ATTRIBUTE_UNUSED
,
318 rtx x
, addr_space_t as ATTRIBUTE_UNUSED
,
319 bool in_const ATTRIBUTE_UNUSED
)
321 #ifndef POINTERS_EXTEND_UNSIGNED
322 gcc_assert (GET_MODE (x
) == to_mode
|| GET_MODE (x
) == VOIDmode
);
324 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
325 enum machine_mode pointer_mode
, address_mode
, from_mode
;
329 /* If X already has the right mode, just return it. */
330 if (GET_MODE (x
) == to_mode
)
333 pointer_mode
= targetm
.addr_space
.pointer_mode (as
);
334 address_mode
= targetm
.addr_space
.address_mode (as
);
335 from_mode
= to_mode
== pointer_mode
? address_mode
: pointer_mode
;
337 /* Here we handle some special cases. If none of them apply, fall through
338 to the default case. */
339 switch (GET_CODE (x
))
341 CASE_CONST_SCALAR_INT
:
342 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
))
344 else if (POINTERS_EXTEND_UNSIGNED
< 0)
346 else if (POINTERS_EXTEND_UNSIGNED
> 0)
350 temp
= simplify_unary_operation (code
, to_mode
, x
, from_mode
);
356 if ((SUBREG_PROMOTED_VAR_P (x
) || REG_POINTER (SUBREG_REG (x
)))
357 && GET_MODE (SUBREG_REG (x
)) == to_mode
)
358 return SUBREG_REG (x
);
362 temp
= gen_rtx_LABEL_REF (to_mode
, LABEL_REF_LABEL (x
));
363 LABEL_REF_NONLOCAL_P (temp
) = LABEL_REF_NONLOCAL_P (x
);
368 temp
= shallow_copy_rtx (x
);
369 PUT_MODE (temp
, to_mode
);
374 return gen_rtx_CONST (to_mode
,
375 convert_memory_address_addr_space_1
376 (to_mode
, XEXP (x
, 0), as
, true));
381 /* For addition we can safely permute the conversion and addition
382 operation if one operand is a constant and converting the constant
383 does not change it or if one operand is a constant and we are
384 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
385 We can always safely permute them if we are making the address
386 narrower. Inside a CONST RTL, this is safe for both pointers
387 zero or sign extended as pointers cannot wrap. */
388 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
)
389 || (GET_CODE (x
) == PLUS
390 && CONST_INT_P (XEXP (x
, 1))
391 && ((in_const
&& POINTERS_EXTEND_UNSIGNED
!= 0)
392 || XEXP (x
, 1) == convert_memory_address_addr_space_1
393 (to_mode
, XEXP (x
, 1), as
, in_const
)
394 || POINTERS_EXTEND_UNSIGNED
< 0)))
395 return gen_rtx_fmt_ee (GET_CODE (x
), to_mode
,
396 convert_memory_address_addr_space_1
397 (to_mode
, XEXP (x
, 0), as
, in_const
),
405 return convert_modes (to_mode
, from_mode
,
406 x
, POINTERS_EXTEND_UNSIGNED
);
407 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
410 /* Given X, a memory address in address space AS' pointer mode, convert it to
411 an address in the address space's address mode, or vice versa (TO_MODE says
412 which way). We take advantage of the fact that pointers are not allowed to
413 overflow by commuting arithmetic operations over conversions so that address
414 arithmetic insns can be used. */
417 convert_memory_address_addr_space (enum machine_mode to_mode
, rtx x
, addr_space_t as
)
419 return convert_memory_address_addr_space_1 (to_mode
, x
, as
, false);
422 /* Return something equivalent to X but valid as a memory address for something
423 of mode MODE in the named address space AS. When X is not itself valid,
424 this works by copying X or subexpressions of it into registers. */
427 memory_address_addr_space (enum machine_mode mode
, rtx x
, addr_space_t as
)
430 enum machine_mode address_mode
= targetm
.addr_space
.address_mode (as
);
432 x
= convert_memory_address_addr_space (address_mode
, x
, as
);
434 /* By passing constant addresses through registers
435 we get a chance to cse them. */
436 if (! cse_not_expected
&& CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
))
437 x
= force_reg (address_mode
, x
);
439 /* We get better cse by rejecting indirect addressing at this stage.
440 Let the combiner create indirect addresses where appropriate.
441 For now, generate the code so that the subexpressions useful to share
442 are visible. But not if cse won't be done! */
445 if (! cse_not_expected
&& !REG_P (x
))
446 x
= break_out_memory_refs (x
);
448 /* At this point, any valid address is accepted. */
449 if (memory_address_addr_space_p (mode
, x
, as
))
452 /* If it was valid before but breaking out memory refs invalidated it,
453 use it the old way. */
454 if (memory_address_addr_space_p (mode
, oldx
, as
))
460 /* Perform machine-dependent transformations on X
461 in certain cases. This is not necessary since the code
462 below can handle all possible cases, but machine-dependent
463 transformations can make better code. */
466 x
= targetm
.addr_space
.legitimize_address (x
, oldx
, mode
, as
);
467 if (orig_x
!= x
&& memory_address_addr_space_p (mode
, x
, as
))
471 /* PLUS and MULT can appear in special ways
472 as the result of attempts to make an address usable for indexing.
473 Usually they are dealt with by calling force_operand, below.
474 But a sum containing constant terms is special
475 if removing them makes the sum a valid address:
476 then we generate that address in a register
477 and index off of it. We do this because it often makes
478 shorter code, and because the addresses thus generated
479 in registers often become common subexpressions. */
480 if (GET_CODE (x
) == PLUS
)
482 rtx constant_term
= const0_rtx
;
483 rtx y
= eliminate_constant_term (x
, &constant_term
);
484 if (constant_term
== const0_rtx
485 || ! memory_address_addr_space_p (mode
, y
, as
))
486 x
= force_operand (x
, NULL_RTX
);
489 y
= gen_rtx_PLUS (GET_MODE (x
), copy_to_reg (y
), constant_term
);
490 if (! memory_address_addr_space_p (mode
, y
, as
))
491 x
= force_operand (x
, NULL_RTX
);
497 else if (GET_CODE (x
) == MULT
|| GET_CODE (x
) == MINUS
)
498 x
= force_operand (x
, NULL_RTX
);
500 /* If we have a register that's an invalid address,
501 it must be a hard reg of the wrong class. Copy it to a pseudo. */
505 /* Last resort: copy the value to a register, since
506 the register is a valid address. */
508 x
= force_reg (address_mode
, x
);
513 gcc_assert (memory_address_addr_space_p (mode
, x
, as
));
514 /* If we didn't change the address, we are done. Otherwise, mark
515 a reg as a pointer if we have REG or REG + CONST_INT. */
519 mark_reg_pointer (x
, BITS_PER_UNIT
);
520 else if (GET_CODE (x
) == PLUS
521 && REG_P (XEXP (x
, 0))
522 && CONST_INT_P (XEXP (x
, 1)))
523 mark_reg_pointer (XEXP (x
, 0), BITS_PER_UNIT
);
525 /* OLDX may have been the address on a temporary. Update the address
526 to indicate that X is now used. */
527 update_temp_slot_address (oldx
, x
);
532 /* If REF is a MEM with an invalid address, change it into a valid address.
533 Pass through anything else unchanged. REF must be an unshared rtx and
534 the function may modify it in-place. */
537 validize_mem (rtx ref
)
541 ref
= use_anchored_address (ref
);
542 if (memory_address_addr_space_p (GET_MODE (ref
), XEXP (ref
, 0),
543 MEM_ADDR_SPACE (ref
)))
546 return replace_equiv_address (ref
, XEXP (ref
, 0), true);
549 /* If X is a memory reference to a member of an object block, try rewriting
550 it to use an anchor instead. Return the new memory reference on success
551 and the old one on failure. */
554 use_anchored_address (rtx x
)
557 HOST_WIDE_INT offset
;
558 enum machine_mode mode
;
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 && CONST_INT_P (XEXP (XEXP (base
, 0), 1)))
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 mode
= GET_MODE (base
);
600 if (!cse_not_expected
)
601 base
= force_reg (mode
, base
);
603 return replace_equiv_address (x
, plus_constant (mode
, base
, offset
));
606 /* Copy the value or contents of X to a new temp reg and return that reg. */
611 rtx temp
= gen_reg_rtx (GET_MODE (x
));
613 /* If not an operand, must be an address with PLUS and MULT so
614 do the computation. */
615 if (! general_operand (x
, VOIDmode
))
616 x
= force_operand (x
, temp
);
619 emit_move_insn (temp
, x
);
624 /* Like copy_to_reg but always give the new register mode Pmode
625 in case X is a constant. */
628 copy_addr_to_reg (rtx x
)
630 return copy_to_mode_reg (Pmode
, x
);
633 /* Like copy_to_reg but always give the new register mode MODE
634 in case X is a constant. */
637 copy_to_mode_reg (enum machine_mode mode
, rtx x
)
639 rtx temp
= gen_reg_rtx (mode
);
641 /* If not an operand, must be an address with PLUS and MULT so
642 do the computation. */
643 if (! general_operand (x
, VOIDmode
))
644 x
= force_operand (x
, temp
);
646 gcc_assert (GET_MODE (x
) == mode
|| GET_MODE (x
) == VOIDmode
);
648 emit_move_insn (temp
, x
);
652 /* Load X into a register if it is not already one.
653 Use mode MODE for the register.
654 X should be valid for mode MODE, but it may be a constant which
655 is valid for all integer modes; that's why caller must specify MODE.
657 The caller must not alter the value in the register we return,
658 since we mark it as a "constant" register. */
661 force_reg (enum machine_mode mode
, rtx x
)
669 if (general_operand (x
, mode
))
671 temp
= gen_reg_rtx (mode
);
672 insn
= emit_move_insn (temp
, x
);
676 temp
= force_operand (x
, NULL_RTX
);
678 insn
= get_last_insn ();
681 rtx temp2
= gen_reg_rtx (mode
);
682 insn
= emit_move_insn (temp2
, temp
);
687 /* Let optimizers know that TEMP's value never changes
688 and that X can be substituted for it. Don't get confused
689 if INSN set something else (such as a SUBREG of TEMP). */
691 && (set
= single_set (insn
)) != 0
692 && SET_DEST (set
) == temp
693 && ! rtx_equal_p (x
, SET_SRC (set
)))
694 set_unique_reg_note (insn
, REG_EQUAL
, x
);
696 /* Let optimizers know that TEMP is a pointer, and if so, the
697 known alignment of that pointer. */
700 if (GET_CODE (x
) == SYMBOL_REF
)
702 align
= BITS_PER_UNIT
;
703 if (SYMBOL_REF_DECL (x
) && DECL_P (SYMBOL_REF_DECL (x
)))
704 align
= DECL_ALIGN (SYMBOL_REF_DECL (x
));
706 else if (GET_CODE (x
) == LABEL_REF
)
707 align
= BITS_PER_UNIT
;
708 else if (GET_CODE (x
) == CONST
709 && GET_CODE (XEXP (x
, 0)) == PLUS
710 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == SYMBOL_REF
711 && CONST_INT_P (XEXP (XEXP (x
, 0), 1)))
713 rtx s
= XEXP (XEXP (x
, 0), 0);
714 rtx c
= XEXP (XEXP (x
, 0), 1);
718 if (SYMBOL_REF_DECL (s
) && DECL_P (SYMBOL_REF_DECL (s
)))
719 sa
= DECL_ALIGN (SYMBOL_REF_DECL (s
));
725 ca
= ctz_hwi (INTVAL (c
)) * BITS_PER_UNIT
;
726 align
= MIN (sa
, ca
);
730 if (align
|| (MEM_P (x
) && MEM_POINTER (x
)))
731 mark_reg_pointer (temp
, align
);
737 /* If X is a memory ref, copy its contents to a new temp reg and return
738 that reg. Otherwise, return X. */
741 force_not_mem (rtx x
)
745 if (!MEM_P (x
) || GET_MODE (x
) == BLKmode
)
748 temp
= gen_reg_rtx (GET_MODE (x
));
751 REG_POINTER (temp
) = 1;
753 emit_move_insn (temp
, x
);
757 /* Copy X to TARGET (if it's nonzero and a reg)
758 or to a new temp reg and return that reg.
759 MODE is the mode to use for X in case it is a constant. */
762 copy_to_suggested_reg (rtx x
, rtx target
, enum machine_mode mode
)
766 if (target
&& REG_P (target
))
769 temp
= gen_reg_rtx (mode
);
771 emit_move_insn (temp
, x
);
775 /* Return the mode to use to pass or return a scalar of TYPE and MODE.
776 PUNSIGNEDP points to the signedness of the type and may be adjusted
777 to show what signedness to use on extension operations.
779 FOR_RETURN is nonzero if the caller is promoting the return value
780 of FNDECL, else it is for promoting args. */
783 promote_function_mode (const_tree type
, enum machine_mode mode
, int *punsignedp
,
784 const_tree funtype
, int for_return
)
786 /* Called without a type node for a libcall. */
787 if (type
== NULL_TREE
)
789 if (INTEGRAL_MODE_P (mode
))
790 return targetm
.calls
.promote_function_mode (NULL_TREE
, mode
,
797 switch (TREE_CODE (type
))
799 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
800 case REAL_TYPE
: case OFFSET_TYPE
: case FIXED_POINT_TYPE
:
801 case POINTER_TYPE
: case REFERENCE_TYPE
:
802 return targetm
.calls
.promote_function_mode (type
, mode
, punsignedp
, funtype
,
809 /* Return the mode to use to store a scalar of TYPE and MODE.
810 PUNSIGNEDP points to the signedness of the type and may be adjusted
811 to show what signedness to use on extension operations. */
814 promote_mode (const_tree type ATTRIBUTE_UNUSED
, enum machine_mode mode
,
815 int *punsignedp ATTRIBUTE_UNUSED
)
822 /* For libcalls this is invoked without TYPE from the backends
823 TARGET_PROMOTE_FUNCTION_MODE hooks. Don't do anything in that
825 if (type
== NULL_TREE
)
828 /* FIXME: this is the same logic that was there until GCC 4.4, but we
829 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
830 is not defined. The affected targets are M32C, S390, SPARC. */
832 code
= TREE_CODE (type
);
833 unsignedp
= *punsignedp
;
837 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
838 case REAL_TYPE
: case OFFSET_TYPE
: case FIXED_POINT_TYPE
:
839 PROMOTE_MODE (mode
, unsignedp
, type
);
840 *punsignedp
= unsignedp
;
844 #ifdef POINTERS_EXTEND_UNSIGNED
847 *punsignedp
= POINTERS_EXTEND_UNSIGNED
;
848 return targetm
.addr_space
.address_mode
849 (TYPE_ADDR_SPACE (TREE_TYPE (type
)));
862 /* Use one of promote_mode or promote_function_mode to find the promoted
863 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
864 of DECL after promotion. */
867 promote_decl_mode (const_tree decl
, int *punsignedp
)
869 tree type
= TREE_TYPE (decl
);
870 int unsignedp
= TYPE_UNSIGNED (type
);
871 enum machine_mode mode
= DECL_MODE (decl
);
872 enum machine_mode pmode
;
874 if (TREE_CODE (decl
) == RESULT_DECL
875 || TREE_CODE (decl
) == PARM_DECL
)
876 pmode
= promote_function_mode (type
, mode
, &unsignedp
,
877 TREE_TYPE (current_function_decl
), 2);
879 pmode
= promote_mode (type
, mode
, &unsignedp
);
882 *punsignedp
= unsignedp
;
887 /* Controls the behaviour of {anti_,}adjust_stack. */
888 static bool suppress_reg_args_size
;
890 /* A helper for adjust_stack and anti_adjust_stack. */
893 adjust_stack_1 (rtx adjust
, bool anti_p
)
898 #ifndef STACK_GROWS_DOWNWARD
899 /* Hereafter anti_p means subtract_p. */
903 temp
= expand_binop (Pmode
,
904 anti_p
? sub_optab
: add_optab
,
905 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
908 if (temp
!= stack_pointer_rtx
)
909 insn
= emit_move_insn (stack_pointer_rtx
, temp
);
912 insn
= get_last_insn ();
913 temp
= single_set (insn
);
914 gcc_assert (temp
!= NULL
&& SET_DEST (temp
) == stack_pointer_rtx
);
917 if (!suppress_reg_args_size
)
918 add_reg_note (insn
, REG_ARGS_SIZE
, GEN_INT (stack_pointer_delta
));
921 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
922 This pops when ADJUST is positive. ADJUST need not be constant. */
925 adjust_stack (rtx adjust
)
927 if (adjust
== const0_rtx
)
930 /* We expect all variable sized adjustments to be multiple of
931 PREFERRED_STACK_BOUNDARY. */
932 if (CONST_INT_P (adjust
))
933 stack_pointer_delta
-= INTVAL (adjust
);
935 adjust_stack_1 (adjust
, false);
938 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
939 This pushes when ADJUST is positive. ADJUST need not be constant. */
942 anti_adjust_stack (rtx adjust
)
944 if (adjust
== const0_rtx
)
947 /* We expect all variable sized adjustments to be multiple of
948 PREFERRED_STACK_BOUNDARY. */
949 if (CONST_INT_P (adjust
))
950 stack_pointer_delta
+= INTVAL (adjust
);
952 adjust_stack_1 (adjust
, true);
955 /* Round the size of a block to be pushed up to the boundary required
956 by this machine. SIZE is the desired size, which need not be constant. */
959 round_push (rtx size
)
961 rtx align_rtx
, alignm1_rtx
;
963 if (!SUPPORTS_STACK_ALIGNMENT
964 || crtl
->preferred_stack_boundary
== MAX_SUPPORTED_STACK_ALIGNMENT
)
966 int align
= crtl
->preferred_stack_boundary
/ BITS_PER_UNIT
;
971 if (CONST_INT_P (size
))
973 HOST_WIDE_INT new_size
= (INTVAL (size
) + align
- 1) / align
* align
;
975 if (INTVAL (size
) != new_size
)
976 size
= GEN_INT (new_size
);
980 align_rtx
= GEN_INT (align
);
981 alignm1_rtx
= GEN_INT (align
- 1);
985 /* If crtl->preferred_stack_boundary might still grow, use
986 virtual_preferred_stack_boundary_rtx instead. This will be
987 substituted by the right value in vregs pass and optimized
989 align_rtx
= virtual_preferred_stack_boundary_rtx
;
990 alignm1_rtx
= force_operand (plus_constant (Pmode
, align_rtx
, -1),
994 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
995 but we know it can't. So add ourselves and then do
997 size
= expand_binop (Pmode
, add_optab
, size
, alignm1_rtx
,
998 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
999 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
, align_rtx
,
1001 size
= expand_mult (Pmode
, size
, align_rtx
, NULL_RTX
, 1);
1006 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
1007 to a previously-created save area. If no save area has been allocated,
1008 this function will allocate one. If a save area is specified, it
1009 must be of the proper mode. */
1012 emit_stack_save (enum save_level save_level
, rtx
*psave
)
1015 /* The default is that we use a move insn and save in a Pmode object. */
1016 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
1017 enum machine_mode mode
= STACK_SAVEAREA_MODE (save_level
);
1019 /* See if this machine has anything special to do for this kind of save. */
1022 #ifdef HAVE_save_stack_block
1024 if (HAVE_save_stack_block
)
1025 fcn
= gen_save_stack_block
;
1028 #ifdef HAVE_save_stack_function
1030 if (HAVE_save_stack_function
)
1031 fcn
= gen_save_stack_function
;
1034 #ifdef HAVE_save_stack_nonlocal
1036 if (HAVE_save_stack_nonlocal
)
1037 fcn
= gen_save_stack_nonlocal
;
1044 /* If there is no save area and we have to allocate one, do so. Otherwise
1045 verify the save area is the proper mode. */
1049 if (mode
!= VOIDmode
)
1051 if (save_level
== SAVE_NONLOCAL
)
1052 *psave
= sa
= assign_stack_local (mode
, GET_MODE_SIZE (mode
), 0);
1054 *psave
= sa
= gen_reg_rtx (mode
);
1058 do_pending_stack_adjust ();
1060 sa
= validize_mem (sa
);
1061 emit_insn (fcn (sa
, stack_pointer_rtx
));
1064 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1065 area made by emit_stack_save. If it is zero, we have nothing to do. */
1068 emit_stack_restore (enum save_level save_level
, rtx sa
)
1070 /* The default is that we use a move insn. */
1071 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
1073 /* If stack_realign_drap, the x86 backend emits a prologue that aligns both
1074 STACK_POINTER and HARD_FRAME_POINTER.
1075 If stack_realign_fp, the x86 backend emits a prologue that aligns only
1076 STACK_POINTER. This renders the HARD_FRAME_POINTER unusable for accessing
1077 aligned variables, which is reflected in ix86_can_eliminate.
1078 We normally still have the realigned STACK_POINTER that we can use.
1079 But if there is a stack restore still present at reload, it can trigger
1080 mark_not_eliminable for the STACK_POINTER, leaving no way to eliminate
1081 FRAME_POINTER into a hard reg.
1082 To prevent this situation, we force need_drap if we emit a stack
1084 if (SUPPORTS_STACK_ALIGNMENT
)
1085 crtl
->need_drap
= true;
1087 /* See if this machine has anything special to do for this kind of save. */
1090 #ifdef HAVE_restore_stack_block
1092 if (HAVE_restore_stack_block
)
1093 fcn
= gen_restore_stack_block
;
1096 #ifdef HAVE_restore_stack_function
1098 if (HAVE_restore_stack_function
)
1099 fcn
= gen_restore_stack_function
;
1102 #ifdef HAVE_restore_stack_nonlocal
1104 if (HAVE_restore_stack_nonlocal
)
1105 fcn
= gen_restore_stack_nonlocal
;
1114 sa
= validize_mem (sa
);
1115 /* These clobbers prevent the scheduler from moving
1116 references to variable arrays below the code
1117 that deletes (pops) the arrays. */
1118 emit_clobber (gen_rtx_MEM (BLKmode
, gen_rtx_SCRATCH (VOIDmode
)));
1119 emit_clobber (gen_rtx_MEM (BLKmode
, stack_pointer_rtx
));
1122 discard_pending_stack_adjust ();
1124 emit_insn (fcn (stack_pointer_rtx
, sa
));
1127 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1128 function. This function should be called whenever we allocate or
1129 deallocate dynamic stack space. */
1132 update_nonlocal_goto_save_area (void)
1137 /* The nonlocal_goto_save_area object is an array of N pointers. The
1138 first one is used for the frame pointer save; the rest are sized by
1139 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1140 of the stack save area slots. */
1141 t_save
= build4 (ARRAY_REF
,
1142 TREE_TYPE (TREE_TYPE (cfun
->nonlocal_goto_save_area
)),
1143 cfun
->nonlocal_goto_save_area
,
1144 integer_one_node
, NULL_TREE
, NULL_TREE
);
1145 r_save
= expand_expr (t_save
, NULL_RTX
, VOIDmode
, EXPAND_WRITE
);
1147 emit_stack_save (SAVE_NONLOCAL
, &r_save
);
1150 /* Return an rtx representing the address of an area of memory dynamically
1151 pushed on the stack.
1153 Any required stack pointer alignment is preserved.
1155 SIZE is an rtx representing the size of the area.
1157 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1158 parameter may be zero. If so, a proper value will be extracted
1159 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1161 REQUIRED_ALIGN is the alignment (in bits) required for the region
1164 If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
1165 stack space allocated by the generated code cannot be added with itself
1166 in the course of the execution of the function. It is always safe to
1167 pass FALSE here and the following criterion is sufficient in order to
1168 pass TRUE: every path in the CFG that starts at the allocation point and
1169 loops to it executes the associated deallocation code. */
1172 allocate_dynamic_stack_space (rtx size
, unsigned size_align
,
1173 unsigned required_align
, bool cannot_accumulate
)
1175 HOST_WIDE_INT stack_usage_size
= -1;
1176 rtx_code_label
*final_label
;
1177 rtx final_target
, target
;
1178 unsigned extra_align
= 0;
1181 /* If we're asking for zero bytes, it doesn't matter what we point
1182 to since we can't dereference it. But return a reasonable
1184 if (size
== const0_rtx
)
1185 return virtual_stack_dynamic_rtx
;
1187 /* Otherwise, show we're calling alloca or equivalent. */
1188 cfun
->calls_alloca
= 1;
1190 /* If stack usage info is requested, look into the size we are passed.
1191 We need to do so this early to avoid the obfuscation that may be
1192 introduced later by the various alignment operations. */
1193 if (flag_stack_usage_info
)
1195 if (CONST_INT_P (size
))
1196 stack_usage_size
= INTVAL (size
);
1197 else if (REG_P (size
))
1199 /* Look into the last emitted insn and see if we can deduce
1200 something for the register. */
1203 insn
= get_last_insn ();
1204 if ((set
= single_set (insn
)) && rtx_equal_p (SET_DEST (set
), size
))
1206 if (CONST_INT_P (SET_SRC (set
)))
1207 stack_usage_size
= INTVAL (SET_SRC (set
));
1208 else if ((note
= find_reg_equal_equiv_note (insn
))
1209 && CONST_INT_P (XEXP (note
, 0)))
1210 stack_usage_size
= INTVAL (XEXP (note
, 0));
1214 /* If the size is not constant, we can't say anything. */
1215 if (stack_usage_size
== -1)
1217 current_function_has_unbounded_dynamic_stack_size
= 1;
1218 stack_usage_size
= 0;
1222 /* Ensure the size is in the proper mode. */
1223 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1224 size
= convert_to_mode (Pmode
, size
, 1);
1226 /* Adjust SIZE_ALIGN, if needed. */
1227 if (CONST_INT_P (size
))
1229 unsigned HOST_WIDE_INT lsb
;
1231 lsb
= INTVAL (size
);
1234 /* Watch out for overflow truncating to "unsigned". */
1235 if (lsb
> UINT_MAX
/ BITS_PER_UNIT
)
1236 size_align
= 1u << (HOST_BITS_PER_INT
- 1);
1238 size_align
= (unsigned)lsb
* BITS_PER_UNIT
;
1240 else if (size_align
< BITS_PER_UNIT
)
1241 size_align
= BITS_PER_UNIT
;
1243 /* We can't attempt to minimize alignment necessary, because we don't
1244 know the final value of preferred_stack_boundary yet while executing
1246 if (crtl
->preferred_stack_boundary
< PREFERRED_STACK_BOUNDARY
)
1247 crtl
->preferred_stack_boundary
= PREFERRED_STACK_BOUNDARY
;
1249 /* We will need to ensure that the address we return is aligned to
1250 REQUIRED_ALIGN. If STACK_DYNAMIC_OFFSET is defined, we don't
1251 always know its final value at this point in the compilation (it
1252 might depend on the size of the outgoing parameter lists, for
1253 example), so we must align the value to be returned in that case.
1254 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1255 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1256 We must also do an alignment operation on the returned value if
1257 the stack pointer alignment is less strict than REQUIRED_ALIGN.
1259 If we have to align, we must leave space in SIZE for the hole
1260 that might result from the alignment operation. */
1262 must_align
= (crtl
->preferred_stack_boundary
< required_align
);
1265 if (required_align
> PREFERRED_STACK_BOUNDARY
)
1266 extra_align
= PREFERRED_STACK_BOUNDARY
;
1267 else if (required_align
> STACK_BOUNDARY
)
1268 extra_align
= STACK_BOUNDARY
;
1270 extra_align
= BITS_PER_UNIT
;
1273 /* ??? STACK_POINTER_OFFSET is always defined now. */
1274 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1276 extra_align
= BITS_PER_UNIT
;
1281 unsigned extra
= (required_align
- extra_align
) / BITS_PER_UNIT
;
1283 size
= plus_constant (Pmode
, size
, extra
);
1284 size
= force_operand (size
, NULL_RTX
);
1286 if (flag_stack_usage_info
)
1287 stack_usage_size
+= extra
;
1289 if (extra
&& size_align
> extra_align
)
1290 size_align
= extra_align
;
1293 /* Round the size to a multiple of the required stack alignment.
1294 Since the stack if presumed to be rounded before this allocation,
1295 this will maintain the required alignment.
1297 If the stack grows downward, we could save an insn by subtracting
1298 SIZE from the stack pointer and then aligning the stack pointer.
1299 The problem with this is that the stack pointer may be unaligned
1300 between the execution of the subtraction and alignment insns and
1301 some machines do not allow this. Even on those that do, some
1302 signal handlers malfunction if a signal should occur between those
1303 insns. Since this is an extremely rare event, we have no reliable
1304 way of knowing which systems have this problem. So we avoid even
1305 momentarily mis-aligning the stack. */
1306 if (size_align
% MAX_SUPPORTED_STACK_ALIGNMENT
!= 0)
1308 size
= round_push (size
);
1310 if (flag_stack_usage_info
)
1312 int align
= crtl
->preferred_stack_boundary
/ BITS_PER_UNIT
;
1313 stack_usage_size
= (stack_usage_size
+ align
- 1) / align
* align
;
1317 target
= gen_reg_rtx (Pmode
);
1319 /* The size is supposed to be fully adjusted at this point so record it
1320 if stack usage info is requested. */
1321 if (flag_stack_usage_info
)
1323 current_function_dynamic_stack_size
+= stack_usage_size
;
1325 /* ??? This is gross but the only safe stance in the absence
1326 of stack usage oriented flow analysis. */
1327 if (!cannot_accumulate
)
1328 current_function_has_unbounded_dynamic_stack_size
= 1;
1332 final_target
= NULL_RTX
;
1334 /* If we are splitting the stack, we need to ask the backend whether
1335 there is enough room on the current stack. If there isn't, or if
1336 the backend doesn't know how to tell is, then we need to call a
1337 function to allocate memory in some other way. This memory will
1338 be released when we release the current stack segment. The
1339 effect is that stack allocation becomes less efficient, but at
1340 least it doesn't cause a stack overflow. */
1341 if (flag_split_stack
)
1343 rtx_code_label
*available_label
;
1344 rtx ask
, space
, func
;
1346 available_label
= NULL
;
1348 #ifdef HAVE_split_stack_space_check
1349 if (HAVE_split_stack_space_check
)
1351 available_label
= gen_label_rtx ();
1353 /* This instruction will branch to AVAILABLE_LABEL if there
1354 are SIZE bytes available on the stack. */
1355 emit_insn (gen_split_stack_space_check (size
, available_label
));
1359 /* The __morestack_allocate_stack_space function will allocate
1360 memory using malloc. If the alignment of the memory returned
1361 by malloc does not meet REQUIRED_ALIGN, we increase SIZE to
1362 make sure we allocate enough space. */
1363 if (MALLOC_ABI_ALIGNMENT
>= required_align
)
1367 ask
= expand_binop (Pmode
, add_optab
, size
,
1368 gen_int_mode (required_align
/ BITS_PER_UNIT
- 1,
1370 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1374 func
= init_one_libfunc ("__morestack_allocate_stack_space");
1376 space
= emit_library_call_value (func
, target
, LCT_NORMAL
, Pmode
,
1379 if (available_label
== NULL_RTX
)
1382 final_target
= gen_reg_rtx (Pmode
);
1384 emit_move_insn (final_target
, space
);
1386 final_label
= gen_label_rtx ();
1387 emit_jump (final_label
);
1389 emit_label (available_label
);
1392 do_pending_stack_adjust ();
1394 /* We ought to be called always on the toplevel and stack ought to be aligned
1396 gcc_assert (!(stack_pointer_delta
1397 % (PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
)));
1399 /* If needed, check that we have the required amount of stack. Take into
1400 account what has already been checked. */
1401 if (STACK_CHECK_MOVING_SP
)
1403 else if (flag_stack_check
== GENERIC_STACK_CHECK
)
1404 probe_stack_range (STACK_OLD_CHECK_PROTECT
+ STACK_CHECK_MAX_FRAME_SIZE
,
1406 else if (flag_stack_check
== STATIC_BUILTIN_STACK_CHECK
)
1407 probe_stack_range (STACK_CHECK_PROTECT
, size
);
1409 /* Don't let anti_adjust_stack emit notes. */
1410 suppress_reg_args_size
= true;
1412 /* Perform the required allocation from the stack. Some systems do
1413 this differently than simply incrementing/decrementing from the
1414 stack pointer, such as acquiring the space by calling malloc(). */
1415 #ifdef HAVE_allocate_stack
1416 if (HAVE_allocate_stack
)
1418 struct expand_operand ops
[2];
1419 /* We don't have to check against the predicate for operand 0 since
1420 TARGET is known to be a pseudo of the proper mode, which must
1421 be valid for the operand. */
1422 create_fixed_operand (&ops
[0], target
);
1423 create_convert_operand_to (&ops
[1], size
, STACK_SIZE_MODE
, true);
1424 expand_insn (CODE_FOR_allocate_stack
, 2, ops
);
1429 int saved_stack_pointer_delta
;
1431 #ifndef STACK_GROWS_DOWNWARD
1432 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1435 /* Check stack bounds if necessary. */
1436 if (crtl
->limit_stack
)
1439 rtx_code_label
*space_available
= gen_label_rtx ();
1440 #ifdef STACK_GROWS_DOWNWARD
1441 available
= expand_binop (Pmode
, sub_optab
,
1442 stack_pointer_rtx
, stack_limit_rtx
,
1443 NULL_RTX
, 1, OPTAB_WIDEN
);
1445 available
= expand_binop (Pmode
, sub_optab
,
1446 stack_limit_rtx
, stack_pointer_rtx
,
1447 NULL_RTX
, 1, OPTAB_WIDEN
);
1449 emit_cmp_and_jump_insns (available
, size
, GEU
, NULL_RTX
, Pmode
, 1,
1453 emit_insn (gen_trap ());
1456 error ("stack limits not supported on this target");
1458 emit_label (space_available
);
1461 saved_stack_pointer_delta
= stack_pointer_delta
;
1463 if (flag_stack_check
&& STACK_CHECK_MOVING_SP
)
1464 anti_adjust_stack_and_probe (size
, false);
1466 anti_adjust_stack (size
);
1468 /* Even if size is constant, don't modify stack_pointer_delta.
1469 The constant size alloca should preserve
1470 crtl->preferred_stack_boundary alignment. */
1471 stack_pointer_delta
= saved_stack_pointer_delta
;
1473 #ifdef STACK_GROWS_DOWNWARD
1474 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1478 suppress_reg_args_size
= false;
1480 /* Finish up the split stack handling. */
1481 if (final_label
!= NULL_RTX
)
1483 gcc_assert (flag_split_stack
);
1484 emit_move_insn (final_target
, target
);
1485 emit_label (final_label
);
1486 target
= final_target
;
1491 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1492 but we know it can't. So add ourselves and then do
1494 target
= expand_binop (Pmode
, add_optab
, target
,
1495 gen_int_mode (required_align
/ BITS_PER_UNIT
- 1,
1497 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1498 target
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, target
,
1499 gen_int_mode (required_align
/ BITS_PER_UNIT
,
1502 target
= expand_mult (Pmode
, target
,
1503 gen_int_mode (required_align
/ BITS_PER_UNIT
,
1508 /* Now that we've committed to a return value, mark its alignment. */
1509 mark_reg_pointer (target
, required_align
);
1511 /* Record the new stack level for nonlocal gotos. */
1512 if (cfun
->nonlocal_goto_save_area
!= 0)
1513 update_nonlocal_goto_save_area ();
1518 /* A front end may want to override GCC's stack checking by providing a
1519 run-time routine to call to check the stack, so provide a mechanism for
1520 calling that routine. */
1522 static GTY(()) rtx stack_check_libfunc
;
1525 set_stack_check_libfunc (const char *libfunc_name
)
1527 gcc_assert (stack_check_libfunc
== NULL_RTX
);
1528 stack_check_libfunc
= gen_rtx_SYMBOL_REF (Pmode
, libfunc_name
);
1531 /* Emit one stack probe at ADDRESS, an address within the stack. */
1534 emit_stack_probe (rtx address
)
1536 #ifdef HAVE_probe_stack_address
1537 if (HAVE_probe_stack_address
)
1538 emit_insn (gen_probe_stack_address (address
));
1542 rtx memref
= gen_rtx_MEM (word_mode
, address
);
1544 MEM_VOLATILE_P (memref
) = 1;
1546 /* See if we have an insn to probe the stack. */
1547 #ifdef HAVE_probe_stack
1548 if (HAVE_probe_stack
)
1549 emit_insn (gen_probe_stack (memref
));
1552 emit_move_insn (memref
, const0_rtx
);
1556 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1557 FIRST is a constant and size is a Pmode RTX. These are offsets from
1558 the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
1559 or subtract them from the stack pointer. */
1561 #define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
1563 #ifdef STACK_GROWS_DOWNWARD
1564 #define STACK_GROW_OP MINUS
1565 #define STACK_GROW_OPTAB sub_optab
1566 #define STACK_GROW_OFF(off) -(off)
1568 #define STACK_GROW_OP PLUS
1569 #define STACK_GROW_OPTAB add_optab
1570 #define STACK_GROW_OFF(off) (off)
1574 probe_stack_range (HOST_WIDE_INT first
, rtx size
)
1576 /* First ensure SIZE is Pmode. */
1577 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1578 size
= convert_to_mode (Pmode
, size
, 1);
1580 /* Next see if we have a function to check the stack. */
1581 if (stack_check_libfunc
)
1583 rtx addr
= memory_address (Pmode
,
1584 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1586 plus_constant (Pmode
,
1588 emit_library_call (stack_check_libfunc
, LCT_NORMAL
, VOIDmode
, 1, addr
,
1592 /* Next see if we have an insn to check the stack. */
1593 #ifdef HAVE_check_stack
1594 else if (HAVE_check_stack
)
1596 struct expand_operand ops
[1];
1597 rtx addr
= memory_address (Pmode
,
1598 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1600 plus_constant (Pmode
,
1603 create_input_operand (&ops
[0], addr
, Pmode
);
1604 success
= maybe_expand_insn (CODE_FOR_check_stack
, 1, ops
);
1605 gcc_assert (success
);
1609 /* Otherwise we have to generate explicit probes. If we have a constant
1610 small number of them to generate, that's the easy case. */
1611 else if (CONST_INT_P (size
) && INTVAL (size
) < 7 * PROBE_INTERVAL
)
1613 HOST_WIDE_INT isize
= INTVAL (size
), i
;
1616 /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until
1617 it exceeds SIZE. If only one probe is needed, this will not
1618 generate any code. Then probe at FIRST + SIZE. */
1619 for (i
= PROBE_INTERVAL
; i
< isize
; i
+= PROBE_INTERVAL
)
1621 addr
= memory_address (Pmode
,
1622 plus_constant (Pmode
, stack_pointer_rtx
,
1623 STACK_GROW_OFF (first
+ i
)));
1624 emit_stack_probe (addr
);
1627 addr
= memory_address (Pmode
,
1628 plus_constant (Pmode
, stack_pointer_rtx
,
1629 STACK_GROW_OFF (first
+ isize
)));
1630 emit_stack_probe (addr
);
1633 /* In the variable case, do the same as above, but in a loop. Note that we
1634 must be extra careful with variables wrapping around because we might be
1635 at the very top (or the very bottom) of the address space and we have to
1636 be able to handle this case properly; in particular, we use an equality
1637 test for the loop condition. */
1640 rtx rounded_size
, rounded_size_op
, test_addr
, last_addr
, temp
;
1641 rtx_code_label
*loop_lab
= gen_label_rtx ();
1642 rtx_code_label
*end_lab
= gen_label_rtx ();
1644 /* Step 1: round SIZE to the previous multiple of the interval. */
1646 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1648 = simplify_gen_binary (AND
, Pmode
, size
,
1649 gen_int_mode (-PROBE_INTERVAL
, Pmode
));
1650 rounded_size_op
= force_operand (rounded_size
, NULL_RTX
);
1653 /* Step 2: compute initial and final value of the loop counter. */
1655 /* TEST_ADDR = SP + FIRST. */
1656 test_addr
= force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1658 gen_int_mode (first
, Pmode
)),
1661 /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
1662 last_addr
= force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1664 rounded_size_op
), NULL_RTX
);
1669 while (TEST_ADDR != LAST_ADDR)
1671 TEST_ADDR = TEST_ADDR + PROBE_INTERVAL
1675 probes at FIRST + N * PROBE_INTERVAL for values of N from 1
1676 until it is equal to ROUNDED_SIZE. */
1678 emit_label (loop_lab
);
1680 /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
1681 emit_cmp_and_jump_insns (test_addr
, last_addr
, EQ
, NULL_RTX
, Pmode
, 1,
1684 /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
1685 temp
= expand_binop (Pmode
, STACK_GROW_OPTAB
, test_addr
,
1686 gen_int_mode (PROBE_INTERVAL
, Pmode
), test_addr
,
1689 gcc_assert (temp
== test_addr
);
1691 /* Probe at TEST_ADDR. */
1692 emit_stack_probe (test_addr
);
1694 emit_jump (loop_lab
);
1696 emit_label (end_lab
);
1699 /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
1700 that SIZE is equal to ROUNDED_SIZE. */
1702 /* TEMP = SIZE - ROUNDED_SIZE. */
1703 temp
= simplify_gen_binary (MINUS
, Pmode
, size
, rounded_size
);
1704 if (temp
!= const0_rtx
)
1708 if (CONST_INT_P (temp
))
1710 /* Use [base + disp} addressing mode if supported. */
1711 HOST_WIDE_INT offset
= INTVAL (temp
);
1712 addr
= memory_address (Pmode
,
1713 plus_constant (Pmode
, last_addr
,
1714 STACK_GROW_OFF (offset
)));
1718 /* Manual CSE if the difference is not known at compile-time. */
1719 temp
= gen_rtx_MINUS (Pmode
, size
, rounded_size_op
);
1720 addr
= memory_address (Pmode
,
1721 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1725 emit_stack_probe (addr
);
1729 /* Make sure nothing is scheduled before we are done. */
1730 emit_insn (gen_blockage ());
1733 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
1734 while probing it. This pushes when SIZE is positive. SIZE need not
1735 be constant. If ADJUST_BACK is true, adjust back the stack pointer
1736 by plus SIZE at the end. */
1739 anti_adjust_stack_and_probe (rtx size
, bool adjust_back
)
1741 /* We skip the probe for the first interval + a small dope of 4 words and
1742 probe that many bytes past the specified size to maintain a protection
1743 area at the botton of the stack. */
1744 const int dope
= 4 * UNITS_PER_WORD
;
1746 /* First ensure SIZE is Pmode. */
1747 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1748 size
= convert_to_mode (Pmode
, size
, 1);
1750 /* If we have a constant small number of probes to generate, that's the
1752 if (CONST_INT_P (size
) && INTVAL (size
) < 7 * PROBE_INTERVAL
)
1754 HOST_WIDE_INT isize
= INTVAL (size
), i
;
1755 bool first_probe
= true;
1757 /* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for
1758 values of N from 1 until it exceeds SIZE. If only one probe is
1759 needed, this will not generate any code. Then adjust and probe
1760 to PROBE_INTERVAL + SIZE. */
1761 for (i
= PROBE_INTERVAL
; i
< isize
; i
+= PROBE_INTERVAL
)
1765 anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL
+ dope
));
1766 first_probe
= false;
1769 anti_adjust_stack (GEN_INT (PROBE_INTERVAL
));
1770 emit_stack_probe (stack_pointer_rtx
);
1774 anti_adjust_stack (plus_constant (Pmode
, size
, PROBE_INTERVAL
+ dope
));
1776 anti_adjust_stack (plus_constant (Pmode
, size
, PROBE_INTERVAL
- i
));
1777 emit_stack_probe (stack_pointer_rtx
);
1780 /* In the variable case, do the same as above, but in a loop. Note that we
1781 must be extra careful with variables wrapping around because we might be
1782 at the very top (or the very bottom) of the address space and we have to
1783 be able to handle this case properly; in particular, we use an equality
1784 test for the loop condition. */
1787 rtx rounded_size
, rounded_size_op
, last_addr
, temp
;
1788 rtx_code_label
*loop_lab
= gen_label_rtx ();
1789 rtx_code_label
*end_lab
= gen_label_rtx ();
1792 /* Step 1: round SIZE to the previous multiple of the interval. */
1794 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1796 = simplify_gen_binary (AND
, Pmode
, size
,
1797 gen_int_mode (-PROBE_INTERVAL
, Pmode
));
1798 rounded_size_op
= force_operand (rounded_size
, NULL_RTX
);
1801 /* Step 2: compute initial and final value of the loop counter. */
1803 /* SP = SP_0 + PROBE_INTERVAL. */
1804 anti_adjust_stack (GEN_INT (PROBE_INTERVAL
+ dope
));
1806 /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */
1807 last_addr
= force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1809 rounded_size_op
), NULL_RTX
);
1814 while (SP != LAST_ADDR)
1816 SP = SP + PROBE_INTERVAL
1820 adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for
1821 values of N from 1 until it is equal to ROUNDED_SIZE. */
1823 emit_label (loop_lab
);
1825 /* Jump to END_LAB if SP == LAST_ADDR. */
1826 emit_cmp_and_jump_insns (stack_pointer_rtx
, last_addr
, EQ
, NULL_RTX
,
1829 /* SP = SP + PROBE_INTERVAL and probe at SP. */
1830 anti_adjust_stack (GEN_INT (PROBE_INTERVAL
));
1831 emit_stack_probe (stack_pointer_rtx
);
1833 emit_jump (loop_lab
);
1835 emit_label (end_lab
);
1838 /* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot
1839 assert at compile-time that SIZE is equal to ROUNDED_SIZE. */
1841 /* TEMP = SIZE - ROUNDED_SIZE. */
1842 temp
= simplify_gen_binary (MINUS
, Pmode
, size
, rounded_size
);
1843 if (temp
!= const0_rtx
)
1845 /* Manual CSE if the difference is not known at compile-time. */
1846 if (GET_CODE (temp
) != CONST_INT
)
1847 temp
= gen_rtx_MINUS (Pmode
, size
, rounded_size_op
);
1848 anti_adjust_stack (temp
);
1849 emit_stack_probe (stack_pointer_rtx
);
1853 /* Adjust back and account for the additional first interval. */
1855 adjust_stack (plus_constant (Pmode
, size
, PROBE_INTERVAL
+ dope
));
1857 adjust_stack (GEN_INT (PROBE_INTERVAL
+ dope
));
1860 /* Return an rtx representing the register or memory location
1861 in which a scalar value of data type VALTYPE
1862 was returned by a function call to function FUNC.
1863 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1864 function is known, otherwise 0.
1865 OUTGOING is 1 if on a machine with register windows this function
1866 should return the register in which the function will put its result
1870 hard_function_value (const_tree valtype
, const_tree func
, const_tree fntype
,
1871 int outgoing ATTRIBUTE_UNUSED
)
1875 val
= targetm
.calls
.function_value (valtype
, func
? func
: fntype
, outgoing
);
1878 && GET_MODE (val
) == BLKmode
)
1880 unsigned HOST_WIDE_INT bytes
= int_size_in_bytes (valtype
);
1881 enum machine_mode tmpmode
;
1883 /* int_size_in_bytes can return -1. We don't need a check here
1884 since the value of bytes will then be large enough that no
1885 mode will match anyway. */
1887 for (tmpmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
1888 tmpmode
!= VOIDmode
;
1889 tmpmode
= GET_MODE_WIDER_MODE (tmpmode
))
1891 /* Have we found a large enough mode? */
1892 if (GET_MODE_SIZE (tmpmode
) >= bytes
)
1896 /* No suitable mode found. */
1897 gcc_assert (tmpmode
!= VOIDmode
);
1899 PUT_MODE (val
, tmpmode
);
1904 /* Return an rtx representing the register or memory location
1905 in which a scalar value of mode MODE was returned by a library call. */
1908 hard_libcall_value (enum machine_mode mode
, rtx fun
)
1910 return targetm
.calls
.libcall_value (mode
, fun
);
1913 /* Look up the tree code for a given rtx code
1914 to provide the arithmetic operation for REAL_ARITHMETIC.
1915 The function returns an int because the caller may not know
1916 what `enum tree_code' means. */
1919 rtx_to_tree_code (enum rtx_code code
)
1921 enum tree_code tcode
;
1944 tcode
= LAST_AND_UNUSED_TREE_CODE
;
1947 return ((int) tcode
);
1950 #include "gt-explow.h"