1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987, 91, 94-97, 1998, 1999 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
29 #include "hard-reg-set.h"
30 #include "insn-config.h"
32 #include "insn-flags.h"
33 #include "insn-codes.h"
35 #if !defined PREFERRED_STACK_BOUNDARY && defined STACK_BOUNDARY
36 #define PREFERRED_STACK_BOUNDARY STACK_BOUNDARY
39 static rtx break_out_memory_refs
PROTO((rtx
));
40 static void emit_stack_probe
PROTO((rtx
));
41 /* Return an rtx for the sum of X and the integer C.
43 This function should be used via the `plus_constant' macro. */
46 plus_constant_wide (x
, c
)
48 register HOST_WIDE_INT c
;
50 register RTX_CODE code
;
51 register enum machine_mode mode
;
65 return GEN_INT (INTVAL (x
) + c
);
69 HOST_WIDE_INT l1
= CONST_DOUBLE_LOW (x
);
70 HOST_WIDE_INT h1
= CONST_DOUBLE_HIGH (x
);
72 HOST_WIDE_INT h2
= c
< 0 ? ~0 : 0;
75 add_double (l1
, h1
, l2
, h2
, &lv
, &hv
);
77 return immed_double_const (lv
, hv
, VOIDmode
);
81 /* If this is a reference to the constant pool, try replacing it with
82 a reference to a new constant. If the resulting address isn't
83 valid, don't return it because we have no way to validize it. */
84 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
85 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
87 /* Any rtl we create here must go in a saveable obstack, since
88 we might have been called from within combine. */
89 push_obstacks_nochange ();
90 rtl_in_saveable_obstack ();
92 = force_const_mem (GET_MODE (x
),
93 plus_constant (get_pool_constant (XEXP (x
, 0)),
96 if (memory_address_p (GET_MODE (tem
), XEXP (tem
, 0)))
102 /* If adding to something entirely constant, set a flag
103 so that we can add a CONST around the result. */
114 /* The interesting case is adding the integer to a sum.
115 Look for constant term in the sum and combine
116 with C. For an integer constant term, we make a combined
117 integer. For a constant term that is not an explicit integer,
118 we cannot really combine, but group them together anyway.
120 Restart or use a recursive call in case the remaining operand is
121 something that we handle specially, such as a SYMBOL_REF.
123 We may not immediately return from the recursive call here, lest
124 all_constant gets lost. */
126 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
)
128 c
+= INTVAL (XEXP (x
, 1));
132 else if (CONSTANT_P (XEXP (x
, 0)))
134 x
= gen_rtx_PLUS (mode
,
135 plus_constant (XEXP (x
, 0), c
),
139 else if (CONSTANT_P (XEXP (x
, 1)))
141 x
= gen_rtx_PLUS (mode
,
143 plus_constant (XEXP (x
, 1), c
));
153 x
= gen_rtx_PLUS (mode
, x
, GEN_INT (c
));
155 if (GET_CODE (x
) == SYMBOL_REF
|| GET_CODE (x
) == LABEL_REF
)
157 else if (all_constant
)
158 return gen_rtx_CONST (mode
, x
);
163 /* This is the same as `plus_constant', except that it handles LO_SUM.
165 This function should be used via the `plus_constant_for_output' macro. */
168 plus_constant_for_output_wide (x
, c
)
170 register HOST_WIDE_INT c
;
172 register enum machine_mode mode
= GET_MODE (x
);
174 if (GET_CODE (x
) == LO_SUM
)
175 return gen_rtx_LO_SUM (mode
, XEXP (x
, 0),
176 plus_constant_for_output (XEXP (x
, 1), c
));
179 return plus_constant (x
, c
);
182 /* If X is a sum, return a new sum like X but lacking any constant terms.
183 Add all the removed constant terms into *CONSTPTR.
184 X itself is not altered. The result != X if and only if
185 it is not isomorphic to X. */
188 eliminate_constant_term (x
, constptr
)
195 if (GET_CODE (x
) != PLUS
)
198 /* First handle constants appearing at this level explicitly. */
199 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
200 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
), *constptr
,
202 && GET_CODE (tem
) == CONST_INT
)
205 return eliminate_constant_term (XEXP (x
, 0), constptr
);
209 x0
= eliminate_constant_term (XEXP (x
, 0), &tem
);
210 x1
= eliminate_constant_term (XEXP (x
, 1), &tem
);
211 if ((x1
!= XEXP (x
, 1) || x0
!= XEXP (x
, 0))
212 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
),
214 && GET_CODE (tem
) == CONST_INT
)
217 return gen_rtx_PLUS (GET_MODE (x
), x0
, x1
);
223 /* Returns the insn that next references REG after INSN, or 0
224 if REG is clobbered before next referenced or we cannot find
225 an insn that references REG in a straight-line piece of code. */
228 find_next_ref (reg
, insn
)
234 for (insn
= NEXT_INSN (insn
); insn
; insn
= next
)
236 next
= NEXT_INSN (insn
);
237 if (GET_CODE (insn
) == NOTE
)
239 if (GET_CODE (insn
) == CODE_LABEL
240 || GET_CODE (insn
) == BARRIER
)
242 if (GET_CODE (insn
) == INSN
243 || GET_CODE (insn
) == JUMP_INSN
244 || GET_CODE (insn
) == CALL_INSN
)
246 if (reg_set_p (reg
, insn
))
248 if (reg_mentioned_p (reg
, PATTERN (insn
)))
250 if (GET_CODE (insn
) == JUMP_INSN
)
252 if (simplejump_p (insn
))
253 next
= JUMP_LABEL (insn
);
257 if (GET_CODE (insn
) == CALL_INSN
258 && REGNO (reg
) < FIRST_PSEUDO_REGISTER
259 && call_used_regs
[REGNO (reg
)])
268 /* Return an rtx for the size in bytes of the value of EXP. */
274 tree size
= size_in_bytes (TREE_TYPE (exp
));
276 if (TREE_CODE (size
) != INTEGER_CST
277 && contains_placeholder_p (size
))
278 size
= build (WITH_RECORD_EXPR
, sizetype
, size
, exp
);
280 return expand_expr (size
, NULL_RTX
, TYPE_MODE (sizetype
),
281 EXPAND_MEMORY_USE_BAD
);
284 /* Return a copy of X in which all memory references
285 and all constants that involve symbol refs
286 have been replaced with new temporary registers.
287 Also emit code to load the memory locations and constants
288 into those registers.
290 If X contains no such constants or memory references,
291 X itself (not a copy) is returned.
293 If a constant is found in the address that is not a legitimate constant
294 in an insn, it is left alone in the hope that it might be valid in the
297 X may contain no arithmetic except addition, subtraction and multiplication.
298 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
301 break_out_memory_refs (x
)
304 if (GET_CODE (x
) == MEM
305 || (CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
)
306 && GET_MODE (x
) != VOIDmode
))
307 x
= force_reg (GET_MODE (x
), x
);
308 else if (GET_CODE (x
) == PLUS
|| GET_CODE (x
) == MINUS
309 || GET_CODE (x
) == MULT
)
311 register rtx op0
= break_out_memory_refs (XEXP (x
, 0));
312 register rtx op1
= break_out_memory_refs (XEXP (x
, 1));
314 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
315 x
= gen_rtx_fmt_ee (GET_CODE (x
), Pmode
, op0
, op1
);
321 #ifdef POINTERS_EXTEND_UNSIGNED
323 /* Given X, a memory address in ptr_mode, convert it to an address
324 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
325 the fact that pointers are not allowed to overflow by commuting arithmetic
326 operations over conversions so that address arithmetic insns can be
330 convert_memory_address (to_mode
, x
)
331 enum machine_mode to_mode
;
334 enum machine_mode from_mode
= to_mode
== ptr_mode
? Pmode
: ptr_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
))
346 temp
= gen_rtx_LABEL_REF (to_mode
, XEXP (x
, 0));
347 LABEL_REF_NONLOCAL_P (temp
) = LABEL_REF_NONLOCAL_P (x
);
351 temp
= gen_rtx_SYMBOL_REF (to_mode
, XSTR (x
, 0));
352 SYMBOL_REF_FLAG (temp
) = SYMBOL_REF_FLAG (x
);
353 CONSTANT_POOL_ADDRESS_P (temp
) = CONSTANT_POOL_ADDRESS_P (x
);
357 return gen_rtx_CONST (to_mode
,
358 convert_memory_address (to_mode
, XEXP (x
, 0)));
362 /* For addition the second operand is a small constant, we can safely
363 permute the conversion and addition operation. We can always safely
364 permute them if we are making the address narrower. In addition,
365 always permute the operations if this is a constant. */
366 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
)
367 || (GET_CODE (x
) == PLUS
&& GET_CODE (XEXP (x
, 1)) == CONST_INT
368 && (INTVAL (XEXP (x
, 1)) + 20000 < 40000
369 || CONSTANT_P (XEXP (x
, 0)))))
370 return gen_rtx_fmt_ee (GET_CODE (x
), to_mode
,
371 convert_memory_address (to_mode
, XEXP (x
, 0)),
372 convert_memory_address (to_mode
, XEXP (x
, 1)));
379 return convert_modes (to_mode
, from_mode
,
380 x
, POINTERS_EXTEND_UNSIGNED
);
384 /* Given a memory address or facsimile X, construct a new address,
385 currently equivalent, that is stable: future stores won't change it.
387 X must be composed of constants, register and memory references
388 combined with addition, subtraction and multiplication:
389 in other words, just what you can get from expand_expr if sum_ok is 1.
391 Works by making copies of all regs and memory locations used
392 by X and combining them the same way X does.
393 You could also stabilize the reference to this address
394 by copying the address to a register with copy_to_reg;
395 but then you wouldn't get indexed addressing in the reference. */
401 if (GET_CODE (x
) == REG
)
403 if (REGNO (x
) != FRAME_POINTER_REGNUM
404 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
405 && REGNO (x
) != HARD_FRAME_POINTER_REGNUM
410 else if (GET_CODE (x
) == MEM
)
412 else if (GET_CODE (x
) == PLUS
|| GET_CODE (x
) == MINUS
413 || GET_CODE (x
) == MULT
)
415 register rtx op0
= copy_all_regs (XEXP (x
, 0));
416 register rtx op1
= copy_all_regs (XEXP (x
, 1));
417 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
418 x
= gen_rtx_fmt_ee (GET_CODE (x
), Pmode
, op0
, op1
);
423 /* Return something equivalent to X but valid as a memory address
424 for something of mode MODE. When X is not itself valid, this
425 works by copying X or subexpressions of it into registers. */
428 memory_address (mode
, x
)
429 enum machine_mode mode
;
432 register rtx oldx
= x
;
434 if (GET_CODE (x
) == ADDRESSOF
)
437 #ifdef POINTERS_EXTEND_UNSIGNED
438 if (GET_MODE (x
) == ptr_mode
)
439 x
= convert_memory_address (Pmode
, x
);
442 /* By passing constant addresses thru registers
443 we get a chance to cse them. */
444 if (! cse_not_expected
&& CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
))
445 x
= force_reg (Pmode
, x
);
447 /* Accept a QUEUED that refers to a REG
448 even though that isn't a valid address.
449 On attempting to put this in an insn we will call protect_from_queue
450 which will turn it into a REG, which is valid. */
451 else if (GET_CODE (x
) == QUEUED
452 && GET_CODE (QUEUED_VAR (x
)) == REG
)
455 /* We get better cse by rejecting indirect addressing at this stage.
456 Let the combiner create indirect addresses where appropriate.
457 For now, generate the code so that the subexpressions useful to share
458 are visible. But not if cse won't be done! */
461 if (! cse_not_expected
&& GET_CODE (x
) != REG
)
462 x
= break_out_memory_refs (x
);
464 /* At this point, any valid address is accepted. */
465 GO_IF_LEGITIMATE_ADDRESS (mode
, x
, win
);
467 /* If it was valid before but breaking out memory refs invalidated it,
468 use it the old way. */
469 if (memory_address_p (mode
, oldx
))
472 /* Perform machine-dependent transformations on X
473 in certain cases. This is not necessary since the code
474 below can handle all possible cases, but machine-dependent
475 transformations can make better code. */
476 LEGITIMIZE_ADDRESS (x
, oldx
, mode
, win
);
478 /* PLUS and MULT can appear in special ways
479 as the result of attempts to make an address usable for indexing.
480 Usually they are dealt with by calling force_operand, below.
481 But a sum containing constant terms is special
482 if removing them makes the sum a valid address:
483 then we generate that address in a register
484 and index off of it. We do this because it often makes
485 shorter code, and because the addresses thus generated
486 in registers often become common subexpressions. */
487 if (GET_CODE (x
) == PLUS
)
489 rtx constant_term
= const0_rtx
;
490 rtx y
= eliminate_constant_term (x
, &constant_term
);
491 if (constant_term
== const0_rtx
492 || ! memory_address_p (mode
, y
))
493 x
= force_operand (x
, NULL_RTX
);
496 y
= gen_rtx_PLUS (GET_MODE (x
), copy_to_reg (y
), constant_term
);
497 if (! memory_address_p (mode
, y
))
498 x
= force_operand (x
, NULL_RTX
);
504 else if (GET_CODE (x
) == MULT
|| GET_CODE (x
) == MINUS
)
505 x
= force_operand (x
, NULL_RTX
);
507 /* If we have a register that's an invalid address,
508 it must be a hard reg of the wrong class. Copy it to a pseudo. */
509 else if (GET_CODE (x
) == REG
)
512 /* Last resort: copy the value to a register, since
513 the register is a valid address. */
515 x
= force_reg (Pmode
, x
);
522 if (flag_force_addr
&& ! cse_not_expected
&& GET_CODE (x
) != REG
523 /* Don't copy an addr via a reg if it is one of our stack slots. */
524 && ! (GET_CODE (x
) == PLUS
525 && (XEXP (x
, 0) == virtual_stack_vars_rtx
526 || XEXP (x
, 0) == virtual_incoming_args_rtx
)))
528 if (general_operand (x
, Pmode
))
529 x
= force_reg (Pmode
, x
);
531 x
= force_operand (x
, NULL_RTX
);
537 /* If we didn't change the address, we are done. Otherwise, mark
538 a reg as a pointer if we have REG or REG + CONST_INT. */
541 else if (GET_CODE (x
) == REG
)
542 mark_reg_pointer (x
, 1);
543 else if (GET_CODE (x
) == PLUS
544 && GET_CODE (XEXP (x
, 0)) == REG
545 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
546 mark_reg_pointer (XEXP (x
, 0), 1);
548 /* OLDX may have been the address on a temporary. Update the address
549 to indicate that X is now used. */
550 update_temp_slot_address (oldx
, x
);
555 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
558 memory_address_noforce (mode
, x
)
559 enum machine_mode mode
;
562 int ambient_force_addr
= flag_force_addr
;
566 val
= memory_address (mode
, x
);
567 flag_force_addr
= ambient_force_addr
;
571 /* Convert a mem ref into one with a valid memory address.
572 Pass through anything else unchanged. */
578 if (GET_CODE (ref
) != MEM
)
580 if (memory_address_p (GET_MODE (ref
), XEXP (ref
, 0)))
582 /* Don't alter REF itself, since that is probably a stack slot. */
583 return change_address (ref
, GET_MODE (ref
), XEXP (ref
, 0));
586 /* Return a modified copy of X with its memory address copied
587 into a temporary register to protect it from side effects.
588 If X is not a MEM, it is returned unchanged (and not copied).
589 Perhaps even if it is a MEM, if there is no need to change it. */
596 if (GET_CODE (x
) != MEM
)
599 if (rtx_unstable_p (addr
))
601 rtx temp
= copy_all_regs (addr
);
603 if (GET_CODE (temp
) != REG
)
604 temp
= copy_to_reg (temp
);
605 mem
= gen_rtx_MEM (GET_MODE (x
), temp
);
607 /* Mark returned memref with in_struct if it's in an array or
608 structure. Copy const and volatile from original memref. */
610 RTX_UNCHANGING_P (mem
) = RTX_UNCHANGING_P (x
);
611 MEM_COPY_ATTRIBUTES (mem
, x
);
612 if (GET_CODE (addr
) == PLUS
)
613 MEM_SET_IN_STRUCT_P (mem
, 1);
615 /* Since the new MEM is just like the old X, it can alias only
616 the things that X could. */
617 MEM_ALIAS_SET (mem
) = MEM_ALIAS_SET (x
);
624 /* Copy the value or contents of X to a new temp reg and return that reg. */
630 register rtx temp
= gen_reg_rtx (GET_MODE (x
));
632 /* If not an operand, must be an address with PLUS and MULT so
633 do the computation. */
634 if (! general_operand (x
, VOIDmode
))
635 x
= force_operand (x
, temp
);
638 emit_move_insn (temp
, x
);
643 /* Like copy_to_reg but always give the new register mode Pmode
644 in case X is a constant. */
650 return copy_to_mode_reg (Pmode
, x
);
653 /* Like copy_to_reg but always give the new register mode MODE
654 in case X is a constant. */
657 copy_to_mode_reg (mode
, x
)
658 enum machine_mode mode
;
661 register rtx temp
= gen_reg_rtx (mode
);
663 /* If not an operand, must be an address with PLUS and MULT so
664 do the computation. */
665 if (! general_operand (x
, VOIDmode
))
666 x
= force_operand (x
, temp
);
668 if (GET_MODE (x
) != mode
&& GET_MODE (x
) != VOIDmode
)
671 emit_move_insn (temp
, x
);
675 /* Load X into a register if it is not already one.
676 Use mode MODE for the register.
677 X should be valid for mode MODE, but it may be a constant which
678 is valid for all integer modes; that's why caller must specify MODE.
680 The caller must not alter the value in the register we return,
681 since we mark it as a "constant" register. */
685 enum machine_mode mode
;
688 register rtx temp
, insn
, set
;
690 if (GET_CODE (x
) == REG
)
692 temp
= gen_reg_rtx (mode
);
693 insn
= emit_move_insn (temp
, x
);
695 /* Let optimizers know that TEMP's value never changes
696 and that X can be substituted for it. Don't get confused
697 if INSN set something else (such as a SUBREG of TEMP). */
699 && (set
= single_set (insn
)) != 0
700 && SET_DEST (set
) == temp
)
702 rtx note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
707 REG_NOTES (insn
) = gen_rtx_EXPR_LIST (REG_EQUAL
, x
, REG_NOTES (insn
));
712 /* If X is a memory ref, copy its contents to a new temp reg and return
713 that reg. Otherwise, return X. */
720 if (GET_CODE (x
) != MEM
|| GET_MODE (x
) == BLKmode
)
722 temp
= gen_reg_rtx (GET_MODE (x
));
723 emit_move_insn (temp
, x
);
727 /* Copy X to TARGET (if it's nonzero and a reg)
728 or to a new temp reg and return that reg.
729 MODE is the mode to use for X in case it is a constant. */
732 copy_to_suggested_reg (x
, target
, mode
)
734 enum machine_mode mode
;
738 if (target
&& GET_CODE (target
) == REG
)
741 temp
= gen_reg_rtx (mode
);
743 emit_move_insn (temp
, x
);
747 /* Return the mode to use to store a scalar of TYPE and MODE.
748 PUNSIGNEDP points to the signedness of the type and may be adjusted
749 to show what signedness to use on extension operations.
751 FOR_CALL is non-zero if this call is promoting args for a call. */
754 promote_mode (type
, mode
, punsignedp
, for_call
)
756 enum machine_mode mode
;
758 int for_call ATTRIBUTE_UNUSED
;
760 enum tree_code code
= TREE_CODE (type
);
761 int unsignedp
= *punsignedp
;
763 #ifdef PROMOTE_FOR_CALL_ONLY
771 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
772 case CHAR_TYPE
: case REAL_TYPE
: case OFFSET_TYPE
:
773 PROMOTE_MODE (mode
, unsignedp
, type
);
777 #ifdef POINTERS_EXTEND_UNSIGNED
781 unsignedp
= POINTERS_EXTEND_UNSIGNED
;
789 *punsignedp
= unsignedp
;
793 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
794 This pops when ADJUST is positive. ADJUST need not be constant. */
797 adjust_stack (adjust
)
801 adjust
= protect_from_queue (adjust
, 0);
803 if (adjust
== const0_rtx
)
806 temp
= expand_binop (Pmode
,
807 #ifdef STACK_GROWS_DOWNWARD
812 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
815 if (temp
!= stack_pointer_rtx
)
816 emit_move_insn (stack_pointer_rtx
, temp
);
819 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
820 This pushes when ADJUST is positive. ADJUST need not be constant. */
823 anti_adjust_stack (adjust
)
827 adjust
= protect_from_queue (adjust
, 0);
829 if (adjust
== const0_rtx
)
832 temp
= expand_binop (Pmode
,
833 #ifdef STACK_GROWS_DOWNWARD
838 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
841 if (temp
!= stack_pointer_rtx
)
842 emit_move_insn (stack_pointer_rtx
, temp
);
845 /* Round the size of a block to be pushed up to the boundary required
846 by this machine. SIZE is the desired size, which need not be constant. */
852 #ifdef PREFERRED_STACK_BOUNDARY
853 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
856 if (GET_CODE (size
) == CONST_INT
)
858 int new = (INTVAL (size
) + align
- 1) / align
* align
;
859 if (INTVAL (size
) != new)
860 size
= GEN_INT (new);
864 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
865 but we know it can't. So add ourselves and then do
867 size
= expand_binop (Pmode
, add_optab
, size
, GEN_INT (align
- 1),
868 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
869 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
, GEN_INT (align
),
871 size
= expand_mult (Pmode
, size
, GEN_INT (align
), NULL_RTX
, 1);
873 #endif /* PREFERRED_STACK_BOUNDARY */
877 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
878 to a previously-created save area. If no save area has been allocated,
879 this function will allocate one. If a save area is specified, it
880 must be of the proper mode.
882 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
883 are emitted at the current position. */
886 emit_stack_save (save_level
, psave
, after
)
887 enum save_level save_level
;
892 /* The default is that we use a move insn and save in a Pmode object. */
893 rtx (*fcn
) PROTO ((rtx
, rtx
)) = gen_move_insn
;
894 enum machine_mode mode
= STACK_SAVEAREA_MODE (save_level
);
896 /* See if this machine has anything special to do for this kind of save. */
899 #ifdef HAVE_save_stack_block
901 if (HAVE_save_stack_block
)
902 fcn
= gen_save_stack_block
;
905 #ifdef HAVE_save_stack_function
907 if (HAVE_save_stack_function
)
908 fcn
= gen_save_stack_function
;
911 #ifdef HAVE_save_stack_nonlocal
913 if (HAVE_save_stack_nonlocal
)
914 fcn
= gen_save_stack_nonlocal
;
921 /* If there is no save area and we have to allocate one, do so. Otherwise
922 verify the save area is the proper mode. */
926 if (mode
!= VOIDmode
)
928 if (save_level
== SAVE_NONLOCAL
)
929 *psave
= sa
= assign_stack_local (mode
, GET_MODE_SIZE (mode
), 0);
931 *psave
= sa
= gen_reg_rtx (mode
);
936 if (mode
== VOIDmode
|| GET_MODE (sa
) != mode
)
945 /* We must validize inside the sequence, to ensure that any instructions
946 created by the validize call also get moved to the right place. */
948 sa
= validize_mem (sa
);
949 emit_insn (fcn (sa
, stack_pointer_rtx
));
950 seq
= gen_sequence ();
952 emit_insn_after (seq
, after
);
957 sa
= validize_mem (sa
);
958 emit_insn (fcn (sa
, stack_pointer_rtx
));
962 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
963 area made by emit_stack_save. If it is zero, we have nothing to do.
965 Put any emitted insns after insn AFTER, if nonzero, otherwise at
969 emit_stack_restore (save_level
, sa
, after
)
970 enum save_level save_level
;
974 /* The default is that we use a move insn. */
975 rtx (*fcn
) PROTO ((rtx
, rtx
)) = gen_move_insn
;
977 /* See if this machine has anything special to do for this kind of save. */
980 #ifdef HAVE_restore_stack_block
982 if (HAVE_restore_stack_block
)
983 fcn
= gen_restore_stack_block
;
986 #ifdef HAVE_restore_stack_function
988 if (HAVE_restore_stack_function
)
989 fcn
= gen_restore_stack_function
;
992 #ifdef HAVE_restore_stack_nonlocal
994 if (HAVE_restore_stack_nonlocal
)
995 fcn
= gen_restore_stack_nonlocal
;
1003 sa
= validize_mem (sa
);
1010 emit_insn (fcn (stack_pointer_rtx
, sa
));
1011 seq
= gen_sequence ();
1013 emit_insn_after (seq
, after
);
1016 emit_insn (fcn (stack_pointer_rtx
, sa
));
1019 #ifdef SETJMP_VIA_SAVE_AREA
1020 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1021 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1022 platforms, the dynamic stack space used can corrupt the original
1023 frame, thus causing a crash if a longjmp unwinds to it. */
1026 optimize_save_area_alloca (insns
)
1031 for (insn
= insns
; insn
; insn
= NEXT_INSN(insn
))
1035 if (GET_CODE (insn
) != INSN
)
1038 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
1040 if (REG_NOTE_KIND (note
) != REG_SAVE_AREA
)
1043 if (!current_function_calls_setjmp
)
1045 rtx pat
= PATTERN (insn
);
1047 /* If we do not see the note in a pattern matching
1048 these precise characteristics, we did something
1049 entirely wrong in allocate_dynamic_stack_space.
1051 Note, one way this could happen is if SETJMP_VIA_SAVE_AREA
1052 was defined on a machine where stacks grow towards higher
1055 Right now only supported port with stack that grow upward
1056 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1057 if (GET_CODE (pat
) != SET
1058 || SET_DEST (pat
) != stack_pointer_rtx
1059 || GET_CODE (SET_SRC (pat
)) != MINUS
1060 || XEXP (SET_SRC (pat
), 0) != stack_pointer_rtx
)
1063 /* This will now be transformed into a (set REG REG)
1064 so we can just blow away all the other notes. */
1065 XEXP (SET_SRC (pat
), 1) = XEXP (note
, 0);
1066 REG_NOTES (insn
) = NULL_RTX
;
1070 /* setjmp was called, we must remove the REG_SAVE_AREA
1071 note so that later passes do not get confused by its
1073 if (note
== REG_NOTES (insn
))
1075 REG_NOTES (insn
) = XEXP (note
, 1);
1081 for (srch
= REG_NOTES (insn
); srch
; srch
= XEXP (srch
, 1))
1082 if (XEXP (srch
, 1) == note
)
1085 if (srch
== NULL_RTX
)
1088 XEXP (srch
, 1) = XEXP (note
, 1);
1091 /* Once we've seen the note of interest, we need not look at
1092 the rest of them. */
1097 #endif /* SETJMP_VIA_SAVE_AREA */
1099 /* Return an rtx representing the address of an area of memory dynamically
1100 pushed on the stack. This region of memory is always aligned to
1101 a multiple of BIGGEST_ALIGNMENT.
1103 Any required stack pointer alignment is preserved.
1105 SIZE is an rtx representing the size of the area.
1106 TARGET is a place in which the address can be placed.
1108 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1111 allocate_dynamic_stack_space (size
, target
, known_align
)
1116 #ifdef SETJMP_VIA_SAVE_AREA
1117 rtx setjmpless_size
= NULL_RTX
;
1120 /* If we're asking for zero bytes, it doesn't matter what we point
1121 to since we can't dereference it. But return a reasonable
1123 if (size
== const0_rtx
)
1124 return virtual_stack_dynamic_rtx
;
1126 /* Otherwise, show we're calling alloca or equivalent. */
1127 current_function_calls_alloca
= 1;
1129 /* Ensure the size is in the proper mode. */
1130 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1131 size
= convert_to_mode (Pmode
, size
, 1);
1133 /* We will need to ensure that the address we return is aligned to
1134 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1135 always know its final value at this point in the compilation (it
1136 might depend on the size of the outgoing parameter lists, for
1137 example), so we must align the value to be returned in that case.
1138 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if
1139 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1140 We must also do an alignment operation on the returned value if
1141 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1143 If we have to align, we must leave space in SIZE for the hole
1144 that might result from the alignment operation. */
1146 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) || ! defined (PREFERRED_STACK_BOUNDARY)
1147 #define MUST_ALIGN 1
1149 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1154 if (GET_CODE (size
) == CONST_INT
)
1155 size
= GEN_INT (INTVAL (size
)
1156 + (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1));
1158 size
= expand_binop (Pmode
, add_optab
, size
,
1159 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1160 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1163 #ifdef SETJMP_VIA_SAVE_AREA
1164 /* If setjmp restores regs from a save area in the stack frame,
1165 avoid clobbering the reg save area. Note that the offset of
1166 virtual_incoming_args_rtx includes the preallocated stack args space.
1167 It would be no problem to clobber that, but it's on the wrong side
1168 of the old save area. */
1171 = expand_binop (Pmode
, sub_optab
, virtual_stack_dynamic_rtx
,
1172 stack_pointer_rtx
, NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1174 if (!current_function_calls_setjmp
)
1176 int align
= PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
;
1178 /* See optimize_save_area_alloca to understand what is being
1181 #if !defined(PREFERRED_STACK_BOUNDARY) || !defined(MUST_ALIGN) || (PREFERRED_STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1182 /* If anyone creates a target with these characteristics, let them
1183 know that our optimization cannot work correctly in such a case. */
1187 if (GET_CODE (size
) == CONST_INT
)
1189 int new = INTVAL (size
) / align
* align
;
1191 if (INTVAL (size
) != new)
1192 setjmpless_size
= GEN_INT (new);
1194 setjmpless_size
= size
;
1198 /* Since we know overflow is not possible, we avoid using
1199 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1200 setjmpless_size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
,
1201 GEN_INT (align
), NULL_RTX
, 1);
1202 setjmpless_size
= expand_mult (Pmode
, setjmpless_size
,
1203 GEN_INT (align
), NULL_RTX
, 1);
1205 /* Our optimization works based upon being able to perform a simple
1206 transformation of this RTL into a (set REG REG) so make sure things
1207 did in fact end up in a REG. */
1208 if (!register_operand (setjmpless_size
, Pmode
))
1209 setjmpless_size
= force_reg (Pmode
, setjmpless_size
);
1212 size
= expand_binop (Pmode
, add_optab
, size
, dynamic_offset
,
1213 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1215 #endif /* SETJMP_VIA_SAVE_AREA */
1217 /* Round the size to a multiple of the required stack alignment.
1218 Since the stack if presumed to be rounded before this allocation,
1219 this will maintain the required alignment.
1221 If the stack grows downward, we could save an insn by subtracting
1222 SIZE from the stack pointer and then aligning the stack pointer.
1223 The problem with this is that the stack pointer may be unaligned
1224 between the execution of the subtraction and alignment insns and
1225 some machines do not allow this. Even on those that do, some
1226 signal handlers malfunction if a signal should occur between those
1227 insns. Since this is an extremely rare event, we have no reliable
1228 way of knowing which systems have this problem. So we avoid even
1229 momentarily mis-aligning the stack. */
1231 #ifdef PREFERRED_STACK_BOUNDARY
1232 /* If we added a variable amount to SIZE,
1233 we can no longer assume it is aligned. */
1234 #if !defined (SETJMP_VIA_SAVE_AREA)
1235 if (MUST_ALIGN
|| known_align
% PREFERRED_STACK_BOUNDARY
!= 0)
1237 size
= round_push (size
);
1240 do_pending_stack_adjust ();
1242 /* If needed, check that we have the required amount of stack. Take into
1243 account what has already been checked. */
1244 if (flag_stack_check
&& ! STACK_CHECK_BUILTIN
)
1245 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE
+ STACK_CHECK_PROTECT
, size
);
1247 /* Don't use a TARGET that isn't a pseudo. */
1248 if (target
== 0 || GET_CODE (target
) != REG
1249 || REGNO (target
) < FIRST_PSEUDO_REGISTER
)
1250 target
= gen_reg_rtx (Pmode
);
1252 mark_reg_pointer (target
, known_align
/ BITS_PER_UNIT
);
1254 /* Perform the required allocation from the stack. Some systems do
1255 this differently than simply incrementing/decrementing from the
1256 stack pointer, such as acquiring the space by calling malloc(). */
1257 #ifdef HAVE_allocate_stack
1258 if (HAVE_allocate_stack
)
1260 enum machine_mode mode
= STACK_SIZE_MODE
;
1262 if (insn_operand_predicate
[(int) CODE_FOR_allocate_stack
][0]
1263 && ! ((*insn_operand_predicate
[(int) CODE_FOR_allocate_stack
][0])
1265 #ifdef POINTERS_EXTEND_UNSIGNED
1266 target
= convert_memory_address (Pmode
, target
);
1268 target
= copy_to_mode_reg (Pmode
, target
);
1270 size
= convert_modes (mode
, ptr_mode
, size
, 1);
1271 if (insn_operand_predicate
[(int) CODE_FOR_allocate_stack
][1]
1272 && ! ((*insn_operand_predicate
[(int) CODE_FOR_allocate_stack
][1])
1274 size
= copy_to_mode_reg (mode
, size
);
1276 emit_insn (gen_allocate_stack (target
, size
));
1281 #ifndef STACK_GROWS_DOWNWARD
1282 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1284 size
= convert_modes (Pmode
, ptr_mode
, size
, 1);
1285 anti_adjust_stack (size
);
1286 #ifdef SETJMP_VIA_SAVE_AREA
1287 if (setjmpless_size
!= NULL_RTX
)
1289 rtx note_target
= get_last_insn ();
1291 REG_NOTES (note_target
)
1292 = gen_rtx_EXPR_LIST (REG_SAVE_AREA
, setjmpless_size
,
1293 REG_NOTES (note_target
));
1295 #endif /* SETJMP_VIA_SAVE_AREA */
1296 #ifdef STACK_GROWS_DOWNWARD
1297 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1303 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1304 but we know it can't. So add ourselves and then do
1306 target
= expand_binop (Pmode
, add_optab
, target
,
1307 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
- 1),
1308 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1309 target
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, target
,
1310 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1312 target
= expand_mult (Pmode
, target
,
1313 GEN_INT (BIGGEST_ALIGNMENT
/ BITS_PER_UNIT
),
1317 /* Some systems require a particular insn to refer to the stack
1318 to make the pages exist. */
1321 emit_insn (gen_probe ());
1324 /* Record the new stack level for nonlocal gotos. */
1325 if (nonlocal_goto_handler_slots
!= 0)
1326 emit_stack_save (SAVE_NONLOCAL
, &nonlocal_goto_stack_level
, NULL_RTX
);
1331 /* Emit one stack probe at ADDRESS, an address within the stack. */
1334 emit_stack_probe (address
)
1337 rtx memref
= gen_rtx_MEM (word_mode
, address
);
1339 MEM_VOLATILE_P (memref
) = 1;
1341 if (STACK_CHECK_PROBE_LOAD
)
1342 emit_move_insn (gen_reg_rtx (word_mode
), memref
);
1344 emit_move_insn (memref
, const0_rtx
);
1347 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1348 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1349 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1350 subtract from the stack. If SIZE is constant, this is done
1351 with a fixed number of probes. Otherwise, we must make a loop. */
1353 #ifdef STACK_GROWS_DOWNWARD
1354 #define STACK_GROW_OP MINUS
1356 #define STACK_GROW_OP PLUS
1360 probe_stack_range (first
, size
)
1361 HOST_WIDE_INT first
;
1364 /* First see if we have an insn to check the stack. Use it if so. */
1365 #ifdef HAVE_check_stack
1366 if (HAVE_check_stack
)
1369 = force_operand (gen_rtx_STACK_GROW_OP (Pmode
,
1371 plus_constant (size
, first
)),
1374 if (insn_operand_predicate
[(int) CODE_FOR_check_stack
][0]
1375 && ! ((*insn_operand_predicate
[(int) CODE_FOR_check_stack
][0])
1376 (last_address
, Pmode
)))
1377 last_address
= copy_to_mode_reg (Pmode
, last_address
);
1379 emit_insn (gen_check_stack (last_address
));
1384 /* If we have to generate explicit probes, see if we have a constant
1385 small number of them to generate. If so, that's the easy case. */
1386 if (GET_CODE (size
) == CONST_INT
1387 && INTVAL (size
) < 10 * STACK_CHECK_PROBE_INTERVAL
)
1389 HOST_WIDE_INT offset
;
1391 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1392 for values of N from 1 until it exceeds LAST. If only one
1393 probe is needed, this will not generate any code. Then probe
1395 for (offset
= first
+ STACK_CHECK_PROBE_INTERVAL
;
1396 offset
< INTVAL (size
);
1397 offset
= offset
+ STACK_CHECK_PROBE_INTERVAL
)
1398 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1402 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1404 plus_constant (size
, first
)));
1407 /* In the variable case, do the same as above, but in a loop. We emit loop
1408 notes so that loop optimization can be done. */
1412 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1414 GEN_INT (first
+ STACK_CHECK_PROBE_INTERVAL
)),
1417 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1419 plus_constant (size
, first
)),
1421 rtx incr
= GEN_INT (STACK_CHECK_PROBE_INTERVAL
);
1422 rtx loop_lab
= gen_label_rtx ();
1423 rtx test_lab
= gen_label_rtx ();
1424 rtx end_lab
= gen_label_rtx ();
1427 if (GET_CODE (test_addr
) != REG
1428 || REGNO (test_addr
) < FIRST_PSEUDO_REGISTER
)
1429 test_addr
= force_reg (Pmode
, test_addr
);
1431 emit_note (NULL_PTR
, NOTE_INSN_LOOP_BEG
);
1432 emit_jump (test_lab
);
1434 emit_label (loop_lab
);
1435 emit_stack_probe (test_addr
);
1437 emit_note (NULL_PTR
, NOTE_INSN_LOOP_CONT
);
1439 #ifdef STACK_GROWS_DOWNWARD
1440 #define CMP_OPCODE GTU
1441 temp
= expand_binop (Pmode
, sub_optab
, test_addr
, incr
, test_addr
,
1444 #define CMP_OPCODE LTU
1445 temp
= expand_binop (Pmode
, add_optab
, test_addr
, incr
, test_addr
,
1449 if (temp
!= test_addr
)
1452 emit_label (test_lab
);
1453 emit_cmp_and_jump_insns (test_addr
, last_addr
, CMP_OPCODE
,
1454 NULL_RTX
, Pmode
, 1, 0, loop_lab
);
1455 emit_jump (end_lab
);
1456 emit_note (NULL_PTR
, NOTE_INSN_LOOP_END
);
1457 emit_label (end_lab
);
1459 /* If will be doing stupid optimization, show test_addr is still live. */
1461 emit_insn (gen_rtx_USE (VOIDmode
, test_addr
));
1463 emit_stack_probe (last_addr
);
1467 /* Return an rtx representing the register or memory location
1468 in which a scalar value of data type VALTYPE
1469 was returned by a function call to function FUNC.
1470 FUNC is a FUNCTION_DECL node if the precise function is known,
1474 hard_function_value (valtype
, func
)
1476 tree func ATTRIBUTE_UNUSED
;
1478 rtx val
= FUNCTION_VALUE (valtype
, func
);
1479 if (GET_CODE (val
) == REG
1480 && GET_MODE (val
) == BLKmode
)
1482 int bytes
= int_size_in_bytes (valtype
);
1483 enum machine_mode tmpmode
;
1484 for (tmpmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
1485 tmpmode
!= MAX_MACHINE_MODE
;
1486 tmpmode
= GET_MODE_WIDER_MODE (tmpmode
))
1488 /* Have we found a large enough mode? */
1489 if (GET_MODE_SIZE (tmpmode
) >= bytes
)
1493 /* No suitable mode found. */
1494 if (tmpmode
== MAX_MACHINE_MODE
)
1497 PUT_MODE (val
, tmpmode
);
1502 /* Return an rtx representing the register or memory location
1503 in which a scalar value of mode MODE was returned by a library call. */
1506 hard_libcall_value (mode
)
1507 enum machine_mode mode
;
1509 return LIBCALL_VALUE (mode
);
1512 /* Look up the tree code for a given rtx code
1513 to provide the arithmetic operation for REAL_ARITHMETIC.
1514 The function returns an int because the caller may not know
1515 what `enum tree_code' means. */
1518 rtx_to_tree_code (code
)
1521 enum tree_code tcode
;
1544 tcode
= LAST_AND_UNUSED_TREE_CODE
;
1547 return ((int) tcode
);