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, 2008
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 (CONST_INT_P (XEXP (x
, 1)))
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 (CONST_INT_P (XEXP (x
, 1))
215 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
), *constptr
,
217 && CONST_INT_P (tem
))
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 && CONST_INT_P (tem
))
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
= tree_expr_size (exp
);
251 gcc_assert (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
= tree_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 && CONST_INT_P (XEXP (x
, 1))
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 for something
409 of mode MODE in the named address space AS. When X is not itself valid,
410 this works by copying X or subexpressions of it into registers. */
413 memory_address_addr_space (enum machine_mode mode
, rtx x
, addr_space_t as
)
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_addr_space_p (mode
, x
, as
))
437 /* If it was valid before but breaking out memory refs invalidated it,
438 use it the old way. */
439 if (memory_address_addr_space_p (mode
, oldx
, as
))
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. */
451 x
= targetm
.addr_space
.legitimize_address (x
, oldx
, mode
, as
);
452 if (orig_x
!= x
&& memory_address_addr_space_p (mode
, x
, as
))
456 /* PLUS and MULT can appear in special ways
457 as the result of attempts to make an address usable for indexing.
458 Usually they are dealt with by calling force_operand, below.
459 But a sum containing constant terms is special
460 if removing them makes the sum a valid address:
461 then we generate that address in a register
462 and index off of it. We do this because it often makes
463 shorter code, and because the addresses thus generated
464 in registers often become common subexpressions. */
465 if (GET_CODE (x
) == PLUS
)
467 rtx constant_term
= const0_rtx
;
468 rtx y
= eliminate_constant_term (x
, &constant_term
);
469 if (constant_term
== const0_rtx
470 || ! memory_address_addr_space_p (mode
, y
, as
))
471 x
= force_operand (x
, NULL_RTX
);
474 y
= gen_rtx_PLUS (GET_MODE (x
), copy_to_reg (y
), constant_term
);
475 if (! memory_address_addr_space_p (mode
, y
, as
))
476 x
= force_operand (x
, NULL_RTX
);
482 else if (GET_CODE (x
) == MULT
|| GET_CODE (x
) == MINUS
)
483 x
= force_operand (x
, NULL_RTX
);
485 /* If we have a register that's an invalid address,
486 it must be a hard reg of the wrong class. Copy it to a pseudo. */
490 /* Last resort: copy the value to a register, since
491 the register is a valid address. */
493 x
= force_reg (Pmode
, x
);
498 gcc_assert (memory_address_addr_space_p (mode
, x
, as
));
499 /* If we didn't change the address, we are done. Otherwise, mark
500 a reg as a pointer if we have REG or REG + CONST_INT. */
504 mark_reg_pointer (x
, BITS_PER_UNIT
);
505 else if (GET_CODE (x
) == PLUS
506 && REG_P (XEXP (x
, 0))
507 && CONST_INT_P (XEXP (x
, 1)))
508 mark_reg_pointer (XEXP (x
, 0), BITS_PER_UNIT
);
510 /* OLDX may have been the address on a temporary. Update the address
511 to indicate that X is now used. */
512 update_temp_slot_address (oldx
, x
);
517 /* Convert a mem ref into one with a valid memory address.
518 Pass through anything else unchanged. */
521 validize_mem (rtx ref
)
525 ref
= use_anchored_address (ref
);
526 if (memory_address_addr_space_p (GET_MODE (ref
), XEXP (ref
, 0),
527 MEM_ADDR_SPACE (ref
)))
530 /* Don't alter REF itself, since that is probably a stack slot. */
531 return replace_equiv_address (ref
, XEXP (ref
, 0));
534 /* If X is a memory reference to a member of an object block, try rewriting
535 it to use an anchor instead. Return the new memory reference on success
536 and the old one on failure. */
539 use_anchored_address (rtx x
)
542 HOST_WIDE_INT offset
;
544 if (!flag_section_anchors
)
550 /* Split the address into a base and offset. */
553 if (GET_CODE (base
) == CONST
554 && GET_CODE (XEXP (base
, 0)) == PLUS
555 && CONST_INT_P (XEXP (XEXP (base
, 0), 1)))
557 offset
+= INTVAL (XEXP (XEXP (base
, 0), 1));
558 base
= XEXP (XEXP (base
, 0), 0);
561 /* Check whether BASE is suitable for anchors. */
562 if (GET_CODE (base
) != SYMBOL_REF
563 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base
)
564 || SYMBOL_REF_ANCHOR_P (base
)
565 || SYMBOL_REF_BLOCK (base
) == NULL
566 || !targetm
.use_anchors_for_symbol_p (base
))
569 /* Decide where BASE is going to be. */
570 place_block_symbol (base
);
572 /* Get the anchor we need to use. */
573 offset
+= SYMBOL_REF_BLOCK_OFFSET (base
);
574 base
= get_section_anchor (SYMBOL_REF_BLOCK (base
), offset
,
575 SYMBOL_REF_TLS_MODEL (base
));
577 /* Work out the offset from the anchor. */
578 offset
-= SYMBOL_REF_BLOCK_OFFSET (base
);
580 /* If we're going to run a CSE pass, force the anchor into a register.
581 We will then be able to reuse registers for several accesses, if the
582 target costs say that that's worthwhile. */
583 if (!cse_not_expected
)
584 base
= force_reg (GET_MODE (base
), base
);
586 return replace_equiv_address (x
, plus_constant (base
, offset
));
589 /* Copy the value or contents of X to a new temp reg and return that reg. */
594 rtx temp
= gen_reg_rtx (GET_MODE (x
));
596 /* If not an operand, must be an address with PLUS and MULT so
597 do the computation. */
598 if (! general_operand (x
, VOIDmode
))
599 x
= force_operand (x
, temp
);
602 emit_move_insn (temp
, x
);
607 /* Like copy_to_reg but always give the new register mode Pmode
608 in case X is a constant. */
611 copy_addr_to_reg (rtx x
)
613 return copy_to_mode_reg (Pmode
, x
);
616 /* Like copy_to_reg but always give the new register mode MODE
617 in case X is a constant. */
620 copy_to_mode_reg (enum machine_mode mode
, rtx x
)
622 rtx temp
= gen_reg_rtx (mode
);
624 /* If not an operand, must be an address with PLUS and MULT so
625 do the computation. */
626 if (! general_operand (x
, VOIDmode
))
627 x
= force_operand (x
, temp
);
629 gcc_assert (GET_MODE (x
) == mode
|| GET_MODE (x
) == VOIDmode
);
631 emit_move_insn (temp
, x
);
635 /* Load X into a register if it is not already one.
636 Use mode MODE for the register.
637 X should be valid for mode MODE, but it may be a constant which
638 is valid for all integer modes; that's why caller must specify MODE.
640 The caller must not alter the value in the register we return,
641 since we mark it as a "constant" register. */
644 force_reg (enum machine_mode mode
, rtx x
)
651 if (general_operand (x
, mode
))
653 temp
= gen_reg_rtx (mode
);
654 insn
= emit_move_insn (temp
, x
);
658 temp
= force_operand (x
, NULL_RTX
);
660 insn
= get_last_insn ();
663 rtx temp2
= gen_reg_rtx (mode
);
664 insn
= emit_move_insn (temp2
, temp
);
669 /* Let optimizers know that TEMP's value never changes
670 and that X can be substituted for it. Don't get confused
671 if INSN set something else (such as a SUBREG of TEMP). */
673 && (set
= single_set (insn
)) != 0
674 && SET_DEST (set
) == temp
675 && ! rtx_equal_p (x
, SET_SRC (set
)))
676 set_unique_reg_note (insn
, REG_EQUAL
, x
);
678 /* Let optimizers know that TEMP is a pointer, and if so, the
679 known alignment of that pointer. */
682 if (GET_CODE (x
) == SYMBOL_REF
)
684 align
= BITS_PER_UNIT
;
685 if (SYMBOL_REF_DECL (x
) && DECL_P (SYMBOL_REF_DECL (x
)))
686 align
= DECL_ALIGN (SYMBOL_REF_DECL (x
));
688 else if (GET_CODE (x
) == LABEL_REF
)
689 align
= BITS_PER_UNIT
;
690 else if (GET_CODE (x
) == CONST
691 && GET_CODE (XEXP (x
, 0)) == PLUS
692 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == SYMBOL_REF
693 && CONST_INT_P (XEXP (XEXP (x
, 0), 1)))
695 rtx s
= XEXP (XEXP (x
, 0), 0);
696 rtx c
= XEXP (XEXP (x
, 0), 1);
700 if (SYMBOL_REF_DECL (s
) && DECL_P (SYMBOL_REF_DECL (s
)))
701 sa
= DECL_ALIGN (SYMBOL_REF_DECL (s
));
703 ca
= exact_log2 (INTVAL (c
) & -INTVAL (c
)) * BITS_PER_UNIT
;
705 align
= MIN (sa
, ca
);
708 if (align
|| (MEM_P (x
) && MEM_POINTER (x
)))
709 mark_reg_pointer (temp
, align
);
715 /* If X is a memory ref, copy its contents to a new temp reg and return
716 that reg. Otherwise, return X. */
719 force_not_mem (rtx x
)
723 if (!MEM_P (x
) || GET_MODE (x
) == BLKmode
)
726 temp
= gen_reg_rtx (GET_MODE (x
));
729 REG_POINTER (temp
) = 1;
731 emit_move_insn (temp
, x
);
735 /* Copy X to TARGET (if it's nonzero and a reg)
736 or to a new temp reg and return that reg.
737 MODE is the mode to use for X in case it is a constant. */
740 copy_to_suggested_reg (rtx x
, rtx target
, enum machine_mode mode
)
744 if (target
&& REG_P (target
))
747 temp
= gen_reg_rtx (mode
);
749 emit_move_insn (temp
, x
);
753 /* Return the mode to use to pass or return a scalar of TYPE and MODE.
754 PUNSIGNEDP points to the signedness of the type and may be adjusted
755 to show what signedness to use on extension operations.
757 FOR_RETURN is nonzero if the caller is promoting the return value
758 of FNDECL, else it is for promoting args. */
761 promote_function_mode (const_tree type
, enum machine_mode mode
, int *punsignedp
,
762 const_tree funtype
, int for_return
)
764 switch (TREE_CODE (type
))
766 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
767 case REAL_TYPE
: case OFFSET_TYPE
: case FIXED_POINT_TYPE
:
768 case POINTER_TYPE
: case REFERENCE_TYPE
:
769 return targetm
.calls
.promote_function_mode (type
, mode
, punsignedp
, funtype
,
776 /* Return the mode to use to store a scalar of TYPE and MODE.
777 PUNSIGNEDP points to the signedness of the type and may be adjusted
778 to show what signedness to use on extension operations. */
781 promote_mode (const_tree type ATTRIBUTE_UNUSED
, enum machine_mode mode
,
782 int *punsignedp ATTRIBUTE_UNUSED
)
784 /* FIXME: this is the same logic that was there until GCC 4.4, but we
785 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
786 is not defined. The affected targets are M32C, S390, SPARC. */
788 const enum tree_code code
= TREE_CODE (type
);
789 int unsignedp
= *punsignedp
;
793 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
794 case REAL_TYPE
: case OFFSET_TYPE
: case FIXED_POINT_TYPE
:
795 PROMOTE_MODE (mode
, unsignedp
, type
);
796 *punsignedp
= unsignedp
;
800 #ifdef POINTERS_EXTEND_UNSIGNED
803 *punsignedp
= POINTERS_EXTEND_UNSIGNED
;
817 /* Use one of promote_mode or promote_function_mode to find the promoted
818 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
819 of DECL after promotion. */
822 promote_decl_mode (const_tree decl
, int *punsignedp
)
824 tree type
= TREE_TYPE (decl
);
825 int unsignedp
= TYPE_UNSIGNED (type
);
826 enum machine_mode mode
= DECL_MODE (decl
);
827 enum machine_mode pmode
;
829 if (TREE_CODE (decl
) == RESULT_DECL
830 || TREE_CODE (decl
) == PARM_DECL
)
831 pmode
= promote_function_mode (type
, mode
, &unsignedp
,
832 TREE_TYPE (current_function_decl
), 2);
834 pmode
= promote_mode (type
, mode
, &unsignedp
);
837 *punsignedp
= unsignedp
;
842 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
843 This pops when ADJUST is positive. ADJUST need not be constant. */
846 adjust_stack (rtx adjust
)
850 if (adjust
== const0_rtx
)
853 /* We expect all variable sized adjustments to be multiple of
854 PREFERRED_STACK_BOUNDARY. */
855 if (CONST_INT_P (adjust
))
856 stack_pointer_delta
-= INTVAL (adjust
);
858 temp
= expand_binop (Pmode
,
859 #ifdef STACK_GROWS_DOWNWARD
864 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
867 if (temp
!= stack_pointer_rtx
)
868 emit_move_insn (stack_pointer_rtx
, temp
);
871 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
872 This pushes when ADJUST is positive. ADJUST need not be constant. */
875 anti_adjust_stack (rtx adjust
)
879 if (adjust
== const0_rtx
)
882 /* We expect all variable sized adjustments to be multiple of
883 PREFERRED_STACK_BOUNDARY. */
884 if (CONST_INT_P (adjust
))
885 stack_pointer_delta
+= INTVAL (adjust
);
887 temp
= expand_binop (Pmode
,
888 #ifdef STACK_GROWS_DOWNWARD
893 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
896 if (temp
!= stack_pointer_rtx
)
897 emit_move_insn (stack_pointer_rtx
, temp
);
900 /* Round the size of a block to be pushed up to the boundary required
901 by this machine. SIZE is the desired size, which need not be constant. */
904 round_push (rtx size
)
906 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
911 if (CONST_INT_P (size
))
913 HOST_WIDE_INT new_size
= (INTVAL (size
) + align
- 1) / align
* align
;
915 if (INTVAL (size
) != new_size
)
916 size
= GEN_INT (new_size
);
920 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
921 but we know it can't. So add ourselves and then do
923 size
= expand_binop (Pmode
, add_optab
, size
, GEN_INT (align
- 1),
924 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
925 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
, GEN_INT (align
),
927 size
= expand_mult (Pmode
, size
, GEN_INT (align
), NULL_RTX
, 1);
933 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
934 to a previously-created save area. If no save area has been allocated,
935 this function will allocate one. If a save area is specified, it
936 must be of the proper mode.
938 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
939 are emitted at the current position. */
942 emit_stack_save (enum save_level save_level
, rtx
*psave
, rtx after
)
945 /* The default is that we use a move insn and save in a Pmode object. */
946 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
947 enum machine_mode mode
= STACK_SAVEAREA_MODE (save_level
);
949 /* See if this machine has anything special to do for this kind of save. */
952 #ifdef HAVE_save_stack_block
954 if (HAVE_save_stack_block
)
955 fcn
= gen_save_stack_block
;
958 #ifdef HAVE_save_stack_function
960 if (HAVE_save_stack_function
)
961 fcn
= gen_save_stack_function
;
964 #ifdef HAVE_save_stack_nonlocal
966 if (HAVE_save_stack_nonlocal
)
967 fcn
= gen_save_stack_nonlocal
;
974 /* If there is no save area and we have to allocate one, do so. Otherwise
975 verify the save area is the proper mode. */
979 if (mode
!= VOIDmode
)
981 if (save_level
== SAVE_NONLOCAL
)
982 *psave
= sa
= assign_stack_local (mode
, GET_MODE_SIZE (mode
), 0);
984 *psave
= sa
= gen_reg_rtx (mode
);
993 do_pending_stack_adjust ();
994 /* We must validize inside the sequence, to ensure that any instructions
995 created by the validize call also get moved to the right place. */
997 sa
= validize_mem (sa
);
998 emit_insn (fcn (sa
, stack_pointer_rtx
));
1001 emit_insn_after (seq
, after
);
1005 do_pending_stack_adjust ();
1007 sa
= validize_mem (sa
);
1008 emit_insn (fcn (sa
, stack_pointer_rtx
));
1012 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1013 area made by emit_stack_save. If it is zero, we have nothing to do.
1015 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1016 current position. */
1019 emit_stack_restore (enum save_level save_level
, rtx sa
, rtx after
)
1021 /* The default is that we use a move insn. */
1022 rtx (*fcn
) (rtx
, rtx
) = gen_move_insn
;
1024 /* See if this machine has anything special to do for this kind of save. */
1027 #ifdef HAVE_restore_stack_block
1029 if (HAVE_restore_stack_block
)
1030 fcn
= gen_restore_stack_block
;
1033 #ifdef HAVE_restore_stack_function
1035 if (HAVE_restore_stack_function
)
1036 fcn
= gen_restore_stack_function
;
1039 #ifdef HAVE_restore_stack_nonlocal
1041 if (HAVE_restore_stack_nonlocal
)
1042 fcn
= gen_restore_stack_nonlocal
;
1051 sa
= validize_mem (sa
);
1052 /* These clobbers prevent the scheduler from moving
1053 references to variable arrays below the code
1054 that deletes (pops) the arrays. */
1055 emit_clobber (gen_rtx_MEM (BLKmode
, gen_rtx_SCRATCH (VOIDmode
)));
1056 emit_clobber (gen_rtx_MEM (BLKmode
, stack_pointer_rtx
));
1059 discard_pending_stack_adjust ();
1066 emit_insn (fcn (stack_pointer_rtx
, sa
));
1069 emit_insn_after (seq
, after
);
1072 emit_insn (fcn (stack_pointer_rtx
, sa
));
1075 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1076 function. This function should be called whenever we allocate or
1077 deallocate dynamic stack space. */
1080 update_nonlocal_goto_save_area (void)
1085 /* The nonlocal_goto_save_area object is an array of N pointers. The
1086 first one is used for the frame pointer save; the rest are sized by
1087 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1088 of the stack save area slots. */
1089 t_save
= build4 (ARRAY_REF
, ptr_type_node
, cfun
->nonlocal_goto_save_area
,
1090 integer_one_node
, NULL_TREE
, NULL_TREE
);
1091 r_save
= expand_expr (t_save
, NULL_RTX
, VOIDmode
, EXPAND_WRITE
);
1093 emit_stack_save (SAVE_NONLOCAL
, &r_save
, NULL_RTX
);
1096 /* Return an rtx representing the address of an area of memory dynamically
1097 pushed on the stack. This region of memory is always aligned to
1098 a multiple of BIGGEST_ALIGNMENT.
1100 Any required stack pointer alignment is preserved.
1102 SIZE is an rtx representing the size of the area.
1103 TARGET is a place in which the address can be placed.
1105 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1108 allocate_dynamic_stack_space (rtx size
, rtx target
, int known_align
)
1110 /* If we're asking for zero bytes, it doesn't matter what we point
1111 to since we can't dereference it. But return a reasonable
1113 if (size
== const0_rtx
)
1114 return virtual_stack_dynamic_rtx
;
1116 /* Otherwise, show we're calling alloca or equivalent. */
1117 cfun
->calls_alloca
= 1;
1119 /* Ensure the size is in the proper mode. */
1120 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1121 size
= convert_to_mode (Pmode
, size
, 1);
1123 /* We can't attempt to minimize alignment necessary, because we don't
1124 know the final value of preferred_stack_boundary yet while executing
1126 crtl
->preferred_stack_boundary
= PREFERRED_STACK_BOUNDARY
;
1128 /* We will need to ensure that the address we return is aligned to
1129 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1130 always know its final value at this point in the compilation (it
1131 might depend on the size of the outgoing parameter lists, for
1132 example), so we must align the value to be returned in that case.
1133 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1134 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1135 We must also do an alignment operation on the returned value if
1136 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1138 If we have to align, we must leave space in SIZE for the hole
1139 that might result from the alignment operation. */
1141 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1142 #define MUST_ALIGN 1
1144 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1149 = force_operand (plus_constant (size
,
1150 BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1153 #ifdef SETJMP_VIA_SAVE_AREA
1154 /* If setjmp restores regs from a save area in the stack frame,
1155 avoid clobbering the reg save area. Note that the offset of
1156 virtual_incoming_args_rtx includes the preallocated stack args space.
1157 It would be no problem to clobber that, but it's on the wrong side
1158 of the old save area.
1160 What used to happen is that, since we did not know for sure
1161 whether setjmp() was invoked until after RTL generation, we
1162 would use reg notes to store the "optimized" size and fix things
1163 up later. These days we know this information before we ever
1164 start building RTL so the reg notes are unnecessary. */
1165 if (!cfun
->calls_setjmp
)
1167 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
1169 /* ??? Code below assumes that the save area needs maximal
1170 alignment. This constraint may be too strong. */
1171 gcc_assert (PREFERRED_STACK_BOUNDARY
== BIGGEST_ALIGNMENT
);
1173 if (CONST_INT_P (size
))
1175 HOST_WIDE_INT new_size
= INTVAL (size
) / align
* align
;
1177 if (INTVAL (size
) != new_size
)
1178 size
= GEN_INT (new_size
);
1182 /* Since we know overflow is not possible, we avoid using
1183 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1184 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
,
1185 GEN_INT (align
), NULL_RTX
, 1);
1186 size
= expand_mult (Pmode
, size
,
1187 GEN_INT (align
), NULL_RTX
, 1);
1193 = expand_binop (Pmode
, sub_optab
, virtual_stack_dynamic_rtx
,
1194 stack_pointer_rtx
, NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1196 size
= expand_binop (Pmode
, add_optab
, size
, dynamic_offset
,
1197 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1199 #endif /* SETJMP_VIA_SAVE_AREA */
1201 /* Round the size to a multiple of the required stack alignment.
1202 Since the stack if presumed to be rounded before this allocation,
1203 this will maintain the required alignment.
1205 If the stack grows downward, we could save an insn by subtracting
1206 SIZE from the stack pointer and then aligning the stack pointer.
1207 The problem with this is that the stack pointer may be unaligned
1208 between the execution of the subtraction and alignment insns and
1209 some machines do not allow this. Even on those that do, some
1210 signal handlers malfunction if a signal should occur between those
1211 insns. Since this is an extremely rare event, we have no reliable
1212 way of knowing which systems have this problem. So we avoid even
1213 momentarily mis-aligning the stack. */
1215 /* If we added a variable amount to SIZE,
1216 we can no longer assume it is aligned. */
1217 #if !defined (SETJMP_VIA_SAVE_AREA)
1218 if (MUST_ALIGN
|| known_align
% PREFERRED_STACK_BOUNDARY
!= 0)
1220 size
= round_push (size
);
1222 do_pending_stack_adjust ();
1224 /* We ought to be called always on the toplevel and stack ought to be aligned
1226 gcc_assert (!(stack_pointer_delta
1227 % (PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
)));
1229 /* If needed, check that we have the required amount of stack.
1230 Take into account what has already been checked. */
1231 if (flag_stack_check
== GENERIC_STACK_CHECK
)
1232 probe_stack_range (STACK_OLD_CHECK_PROTECT
+ STACK_CHECK_MAX_FRAME_SIZE
,
1234 else if (flag_stack_check
== STATIC_BUILTIN_STACK_CHECK
)
1235 probe_stack_range (STACK_CHECK_PROTECT
, size
);
1237 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1238 if (target
== 0 || !REG_P (target
)
1239 || REGNO (target
) < FIRST_PSEUDO_REGISTER
1240 || GET_MODE (target
) != Pmode
)
1241 target
= gen_reg_rtx (Pmode
);
1243 mark_reg_pointer (target
, known_align
);
1245 /* Perform the required allocation from the stack. Some systems do
1246 this differently than simply incrementing/decrementing from the
1247 stack pointer, such as acquiring the space by calling malloc(). */
1248 #ifdef HAVE_allocate_stack
1249 if (HAVE_allocate_stack
)
1251 enum machine_mode mode
= STACK_SIZE_MODE
;
1252 insn_operand_predicate_fn pred
;
1254 /* We don't have to check against the predicate for operand 0 since
1255 TARGET is known to be a pseudo of the proper mode, which must
1256 be valid for the operand. For operand 1, convert to the
1257 proper mode and validate. */
1258 if (mode
== VOIDmode
)
1259 mode
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].mode
;
1261 pred
= insn_data
[(int) CODE_FOR_allocate_stack
].operand
[1].predicate
;
1262 if (pred
&& ! ((*pred
) (size
, mode
)))
1263 size
= copy_to_mode_reg (mode
, convert_to_mode (mode
, size
, 1));
1265 emit_insn (gen_allocate_stack (target
, size
));
1270 #ifndef STACK_GROWS_DOWNWARD
1271 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1274 /* Check stack bounds if necessary. */
1275 if (crtl
->limit_stack
)
1278 rtx space_available
= gen_label_rtx ();
1279 #ifdef STACK_GROWS_DOWNWARD
1280 available
= expand_binop (Pmode
, sub_optab
,
1281 stack_pointer_rtx
, stack_limit_rtx
,
1282 NULL_RTX
, 1, OPTAB_WIDEN
);
1284 available
= expand_binop (Pmode
, sub_optab
,
1285 stack_limit_rtx
, stack_pointer_rtx
,
1286 NULL_RTX
, 1, OPTAB_WIDEN
);
1288 emit_cmp_and_jump_insns (available
, size
, GEU
, NULL_RTX
, Pmode
, 1,
1292 emit_insn (gen_trap ());
1295 error ("stack limits not supported on this target");
1297 emit_label (space_available
);
1300 anti_adjust_stack (size
);
1302 #ifdef STACK_GROWS_DOWNWARD
1303 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1309 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1310 but we know it can't. So add ourselves and then do
1312 target
= expand_binop (Pmode
, add_optab
, target
,
1313 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1314 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1315 target
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, target
,
1316 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1318 target
= expand_mult (Pmode
, target
,
1319 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1323 /* Record the new stack level for nonlocal gotos. */
1324 if (cfun
->nonlocal_goto_save_area
!= 0)
1325 update_nonlocal_goto_save_area ();
1330 /* A front end may want to override GCC's stack checking by providing a
1331 run-time routine to call to check the stack, so provide a mechanism for
1332 calling that routine. */
1334 static GTY(()) rtx stack_check_libfunc
;
1337 set_stack_check_libfunc (rtx libfunc
)
1339 stack_check_libfunc
= libfunc
;
1342 /* Emit one stack probe at ADDRESS, an address within the stack. */
1345 emit_stack_probe (rtx address
)
1347 rtx memref
= gen_rtx_MEM (word_mode
, address
);
1349 MEM_VOLATILE_P (memref
) = 1;
1351 if (STACK_CHECK_PROBE_LOAD
)
1352 emit_move_insn (gen_reg_rtx (word_mode
), memref
);
1354 emit_move_insn (memref
, const0_rtx
);
1357 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1358 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1359 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1360 subtract from the stack. If SIZE is constant, this is done
1361 with a fixed number of probes. Otherwise, we must make a loop. */
1363 #ifdef STACK_GROWS_DOWNWARD
1364 #define STACK_GROW_OP MINUS
1366 #define STACK_GROW_OP PLUS
1370 probe_stack_range (HOST_WIDE_INT first
, rtx size
)
1372 /* First ensure SIZE is Pmode. */
1373 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1374 size
= convert_to_mode (Pmode
, size
, 1);
1376 /* Next see if the front end has set up a function for us to call to
1378 if (stack_check_libfunc
!= 0)
1380 rtx addr
= memory_address (QImode
,
1381 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1383 plus_constant (size
, first
)));
1385 addr
= convert_memory_address (ptr_mode
, addr
);
1386 emit_library_call (stack_check_libfunc
, LCT_NORMAL
, VOIDmode
, 1, addr
,
1390 /* Next see if we have an insn to check the stack. Use it if so. */
1391 #ifdef HAVE_check_stack
1392 else if (HAVE_check_stack
)
1394 insn_operand_predicate_fn pred
;
1396 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1398 plus_constant (size
, first
)),
1401 pred
= insn_data
[(int) CODE_FOR_check_stack
].operand
[0].predicate
;
1402 if (pred
&& ! ((*pred
) (last_addr
, Pmode
)))
1403 last_addr
= copy_to_mode_reg (Pmode
, last_addr
);
1405 emit_insn (gen_check_stack (last_addr
));
1409 /* If we have to generate explicit probes, see if we have a constant
1410 small number of them to generate. If so, that's the easy case. */
1411 else if (CONST_INT_P (size
)
1412 && INTVAL (size
) < 10 * STACK_CHECK_PROBE_INTERVAL
)
1414 HOST_WIDE_INT offset
;
1416 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1417 for values of N from 1 until it exceeds LAST. If only one
1418 probe is needed, this will not generate any code. Then probe
1420 for (offset
= first
+ STACK_CHECK_PROBE_INTERVAL
;
1421 offset
< INTVAL (size
);
1422 offset
= offset
+ STACK_CHECK_PROBE_INTERVAL
)
1423 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1427 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1429 plus_constant (size
, first
)));
1432 /* In the variable case, do the same as above, but in a loop. We emit loop
1433 notes so that loop optimization can be done. */
1437 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1439 GEN_INT (first
+ STACK_CHECK_PROBE_INTERVAL
)),
1442 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1444 plus_constant (size
, first
)),
1446 rtx incr
= GEN_INT (STACK_CHECK_PROBE_INTERVAL
);
1447 rtx loop_lab
= gen_label_rtx ();
1448 rtx test_lab
= gen_label_rtx ();
1449 rtx end_lab
= gen_label_rtx ();
1452 if (!REG_P (test_addr
)
1453 || REGNO (test_addr
) < FIRST_PSEUDO_REGISTER
)
1454 test_addr
= force_reg (Pmode
, test_addr
);
1456 emit_jump (test_lab
);
1458 emit_label (loop_lab
);
1459 emit_stack_probe (test_addr
);
1461 #ifdef STACK_GROWS_DOWNWARD
1462 #define CMP_OPCODE GTU
1463 temp
= expand_binop (Pmode
, sub_optab
, test_addr
, incr
, test_addr
,
1466 #define CMP_OPCODE LTU
1467 temp
= expand_binop (Pmode
, add_optab
, test_addr
, incr
, test_addr
,
1471 gcc_assert (temp
== test_addr
);
1473 emit_label (test_lab
);
1474 emit_cmp_and_jump_insns (test_addr
, last_addr
, CMP_OPCODE
,
1475 NULL_RTX
, Pmode
, 1, loop_lab
);
1476 emit_jump (end_lab
);
1477 emit_label (end_lab
);
1479 emit_stack_probe (last_addr
);
1483 /* Return an rtx representing the register or memory location
1484 in which a scalar value of data type VALTYPE
1485 was returned by a function call to function FUNC.
1486 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1487 function is known, otherwise 0.
1488 OUTGOING is 1 if on a machine with register windows this function
1489 should return the register in which the function will put its result
1493 hard_function_value (const_tree valtype
, const_tree func
, const_tree fntype
,
1494 int outgoing ATTRIBUTE_UNUSED
)
1498 val
= targetm
.calls
.function_value (valtype
, func
? func
: fntype
, outgoing
);
1501 && GET_MODE (val
) == BLKmode
)
1503 unsigned HOST_WIDE_INT bytes
= int_size_in_bytes (valtype
);
1504 enum machine_mode tmpmode
;
1506 /* int_size_in_bytes can return -1. We don't need a check here
1507 since the value of bytes will then be large enough that no
1508 mode will match anyway. */
1510 for (tmpmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
1511 tmpmode
!= VOIDmode
;
1512 tmpmode
= GET_MODE_WIDER_MODE (tmpmode
))
1514 /* Have we found a large enough mode? */
1515 if (GET_MODE_SIZE (tmpmode
) >= bytes
)
1519 /* No suitable mode found. */
1520 gcc_assert (tmpmode
!= VOIDmode
);
1522 PUT_MODE (val
, tmpmode
);
1527 /* Return an rtx representing the register or memory location
1528 in which a scalar value of mode MODE was returned by a library call. */
1531 hard_libcall_value (enum machine_mode mode
, rtx fun
)
1533 return targetm
.calls
.libcall_value (mode
, fun
);
1536 /* Look up the tree code for a given rtx code
1537 to provide the arithmetic operation for REAL_ARITHMETIC.
1538 The function returns an int because the caller may not know
1539 what `enum tree_code' means. */
1542 rtx_to_tree_code (enum rtx_code code
)
1544 enum tree_code tcode
;
1567 tcode
= LAST_AND_UNUSED_TREE_CODE
;
1570 return ((int) tcode
);
1573 #include "gt-explow.h"