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;
56 && !(flag_propolice_protection && x == virtual_stack_vars_rtx))
66 return GEN_INT (INTVAL (x) + c);
70 HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
71 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
73 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
76 add_double (l1, h1, l2, h2, &lv, &hv);
78 return immed_double_const (lv, hv, VOIDmode);
82 /* If this is a reference to the constant pool, try replacing it with
83 a reference to a new constant. If the resulting address isn't
84 valid, don't return it because we have no way to validize it. */
85 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
86 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
88 /* Any rtl we create here must go in a saveable obstack, since
89 we might have been called from within combine. */
90 push_obstacks_nochange ();
91 rtl_in_saveable_obstack ();
93 = force_const_mem (GET_MODE (x),
94 plus_constant (get_pool_constant (XEXP (x, 0)),
97 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
103 /* If adding to something entirely constant, set a flag
104 so that we can add a CONST around the result. */
115 /* The interesting case is adding the integer to a sum.
116 Look for constant term in the sum and combine
117 with C. For an integer constant term, we make a combined
118 integer. For a constant term that is not an explicit integer,
119 we cannot really combine, but group them together anyway.
121 Restart or use a recursive call in case the remaining operand is
122 something that we handle specially, such as a SYMBOL_REF.
124 We may not immediately return from the recursive call here, lest
125 all_constant gets lost. */
127 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
129 c += INTVAL (XEXP (x, 1));
133 else if (CONSTANT_P (XEXP (x, 0)))
135 x = gen_rtx_PLUS (mode,
136 plus_constant (XEXP (x, 0), c),
140 else if (CONSTANT_P (XEXP (x, 1)))
142 x = gen_rtx_PLUS (mode,
144 plus_constant (XEXP (x, 1), c));
154 || (flag_propolice_protection && x == virtual_stack_vars_rtx))
155 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
157 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
159 else if (all_constant)
160 return gen_rtx_CONST (mode, x);
165 /* This is the same as `plus_constant', except that it handles LO_SUM.
167 This function should be used via the `plus_constant_for_output' macro. */
170 plus_constant_for_output_wide (x, c)
172 register HOST_WIDE_INT c;
174 register enum machine_mode mode = GET_MODE (x);
176 if (GET_CODE (x) == LO_SUM)
177 return gen_rtx_LO_SUM (mode, XEXP (x, 0),
178 plus_constant_for_output (XEXP (x, 1), c));
181 return plus_constant (x, c);
184 /* If X is a sum, return a new sum like X but lacking any constant terms.
185 Add all the removed constant terms into *CONSTPTR.
186 X itself is not altered. The result != X if and only if
187 it is not isomorphic to X. */
190 eliminate_constant_term (x, constptr)
197 if (GET_CODE (x) != PLUS)
200 /* First handle constants appearing at this level explicitly. */
201 if (GET_CODE (XEXP (x, 1)) == CONST_INT
202 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
204 && GET_CODE (tem) == CONST_INT)
207 return eliminate_constant_term (XEXP (x, 0), constptr);
211 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
212 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
213 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
214 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
216 && GET_CODE (tem) == CONST_INT)
219 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
225 /* Returns the insn that next references REG after INSN, or 0
226 if REG is clobbered before next referenced or we cannot find
227 an insn that references REG in a straight-line piece of code. */
230 find_next_ref (reg, insn)
236 for (insn = NEXT_INSN (insn); insn; insn = next)
238 next = NEXT_INSN (insn);
239 if (GET_CODE (insn) == NOTE)
241 if (GET_CODE (insn) == CODE_LABEL
242 || GET_CODE (insn) == BARRIER)
244 if (GET_CODE (insn) == INSN
245 || GET_CODE (insn) == JUMP_INSN
246 || GET_CODE (insn) == CALL_INSN)
248 if (reg_set_p (reg, insn))
250 if (reg_mentioned_p (reg, PATTERN (insn)))
252 if (GET_CODE (insn) == JUMP_INSN)
254 if (simplejump_p (insn))
255 next = JUMP_LABEL (insn);
259 if (GET_CODE (insn) == CALL_INSN
260 && REGNO (reg) < FIRST_PSEUDO_REGISTER
261 && call_used_regs[REGNO (reg)])
270 /* Return an rtx for the size in bytes of the value of EXP. */
276 tree size = size_in_bytes (TREE_TYPE (exp));
278 if (TREE_CODE (size) != INTEGER_CST
279 && contains_placeholder_p (size))
280 size = build (WITH_RECORD_EXPR, sizetype, size, exp);
282 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype),
283 EXPAND_MEMORY_USE_BAD);
286 /* Return a copy of X in which all memory references
287 and all constants that involve symbol refs
288 have been replaced with new temporary registers.
289 Also emit code to load the memory locations and constants
290 into those registers.
292 If X contains no such constants or memory references,
293 X itself (not a copy) is returned.
295 If a constant is found in the address that is not a legitimate constant
296 in an insn, it is left alone in the hope that it might be valid in the
299 X may contain no arithmetic except addition, subtraction and multiplication.
300 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
303 break_out_memory_refs (x)
306 if (GET_CODE (x) == MEM
307 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
308 && GET_MODE (x) != VOIDmode))
309 x = force_reg (GET_MODE (x), x);
310 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
311 || GET_CODE (x) == MULT)
313 register rtx op0 = break_out_memory_refs (XEXP (x, 0));
314 register rtx op1 = break_out_memory_refs (XEXP (x, 1));
316 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
317 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
323 #ifdef POINTERS_EXTEND_UNSIGNED
325 /* Given X, a memory address in ptr_mode, convert it to an address
326 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
327 the fact that pointers are not allowed to overflow by commuting arithmetic
328 operations over conversions so that address arithmetic insns can be
332 convert_memory_address (to_mode, x)
333 enum machine_mode to_mode;
336 enum machine_mode 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))
348 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
349 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
353 temp = gen_rtx_SYMBOL_REF (to_mode, XSTR (x, 0));
354 SYMBOL_REF_FLAG (temp) = SYMBOL_REF_FLAG (x);
355 CONSTANT_POOL_ADDRESS_P (temp) = CONSTANT_POOL_ADDRESS_P (x);
359 return gen_rtx_CONST (to_mode,
360 convert_memory_address (to_mode, XEXP (x, 0)));
364 /* For addition the second operand is a small constant, we can safely
365 permute the conversion and addition operation. We can always safely
366 permute them if we are making the address narrower. In addition,
367 always permute the operations if this is a constant. */
368 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
369 || (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 1)) == CONST_INT
370 && (INTVAL (XEXP (x, 1)) + 20000 < 40000
371 || CONSTANT_P (XEXP (x, 0)))))
372 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
373 convert_memory_address (to_mode, XEXP (x, 0)),
374 convert_memory_address (to_mode, XEXP (x, 1)));
381 return convert_modes (to_mode, from_mode,
382 x, POINTERS_EXTEND_UNSIGNED);
386 /* Given a memory address or facsimile X, construct a new address,
387 currently equivalent, that is stable: future stores won't change it.
389 X must be composed of constants, register and memory references
390 combined with addition, subtraction and multiplication:
391 in other words, just what you can get from expand_expr if sum_ok is 1.
393 Works by making copies of all regs and memory locations used
394 by X and combining them the same way X does.
395 You could also stabilize the reference to this address
396 by copying the address to a register with copy_to_reg;
397 but then you wouldn't get indexed addressing in the reference. */
403 if (GET_CODE (x) == REG)
405 if (REGNO (x) != FRAME_POINTER_REGNUM
406 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
407 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
412 else if (GET_CODE (x) == MEM)
414 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
415 || GET_CODE (x) == MULT)
417 register rtx op0 = copy_all_regs (XEXP (x, 0));
418 register rtx op1 = copy_all_regs (XEXP (x, 1));
419 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
420 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
425 /* Return something equivalent to X but valid as a memory address
426 for something of mode MODE. When X is not itself valid, this
427 works by copying X or subexpressions of it into registers. */
430 memory_address (mode, x)
431 enum machine_mode mode;
434 register rtx oldx = x;
436 if (GET_CODE (x) == ADDRESSOF)
439 #ifdef POINTERS_EXTEND_UNSIGNED
440 if (GET_MODE (x) == ptr_mode)
441 x = convert_memory_address (Pmode, x);
444 /* By passing constant addresses thru registers
445 we get a chance to cse them. */
446 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
447 x = force_reg (Pmode, x);
449 /* Accept a QUEUED that refers to a REG
450 even though that isn't a valid address.
451 On attempting to put this in an insn we will call protect_from_queue
452 which will turn it into a REG, which is valid. */
453 else if (GET_CODE (x) == QUEUED
454 && GET_CODE (QUEUED_VAR (x)) == REG)
457 /* We get better cse by rejecting indirect addressing at this stage.
458 Let the combiner create indirect addresses where appropriate.
459 For now, generate the code so that the subexpressions useful to share
460 are visible. But not if cse won't be done! */
463 if (! cse_not_expected && GET_CODE (x) != REG)
464 x = break_out_memory_refs (x);
466 /* At this point, any valid address is accepted. */
467 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
469 /* If it was valid before but breaking out memory refs invalidated it,
470 use it the old way. */
471 if (memory_address_p (mode, oldx))
474 /* Perform machine-dependent transformations on X
475 in certain cases. This is not necessary since the code
476 below can handle all possible cases, but machine-dependent
477 transformations can make better code. */
478 if (flag_propolice_protection)
480 #define FRAMEADDR_P(X) (GET_CODE (X) == PLUS \
481 && XEXP (X, 0) == virtual_stack_vars_rtx \
482 && GET_CODE (XEXP (X, 1)) == CONST_INT)
484 if (FRAMEADDR_P (x)) goto win;
485 for (y=x; y!=0 && GET_CODE (y)==PLUS; y = XEXP (y, 0))
487 if (FRAMEADDR_P (XEXP (y, 0)))
488 XEXP (y, 0) = force_reg (GET_MODE (XEXP (y, 0)), XEXP (y, 0));
489 if (FRAMEADDR_P (XEXP (y, 1)))
490 XEXP (y, 1) = force_reg (GET_MODE (XEXP (y, 1)), XEXP (y, 1));
493 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
495 /* PLUS and MULT can appear in special ways
496 as the result of attempts to make an address usable for indexing.
497 Usually they are dealt with by calling force_operand, below.
498 But a sum containing constant terms is special
499 if removing them makes the sum a valid address:
500 then we generate that address in a register
501 and index off of it. We do this because it often makes
502 shorter code, and because the addresses thus generated
503 in registers often become common subexpressions. */
504 if (GET_CODE (x) == PLUS)
506 rtx constant_term = const0_rtx;
507 rtx y = eliminate_constant_term (x, &constant_term);
508 if (constant_term == const0_rtx
509 || ! memory_address_p (mode, y))
510 x = force_operand (x, NULL_RTX);
513 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
514 if (! memory_address_p (mode, y))
515 x = force_operand (x, NULL_RTX);
521 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
522 x = force_operand (x, NULL_RTX);
524 /* If we have a register that's an invalid address,
525 it must be a hard reg of the wrong class. Copy it to a pseudo. */
526 else if (GET_CODE (x) == REG)
529 /* Last resort: copy the value to a register, since
530 the register is a valid address. */
532 x = force_reg (Pmode, x);
539 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG
540 /* Don't copy an addr via a reg if it is one of our stack slots. */
541 && ! (GET_CODE (x) == PLUS
542 && (XEXP (x, 0) == virtual_stack_vars_rtx
543 || XEXP (x, 0) == virtual_incoming_args_rtx)))
545 if (general_operand (x, Pmode))
546 x = force_reg (Pmode, x);
548 x = force_operand (x, NULL_RTX);
554 /* If we didn't change the address, we are done. Otherwise, mark
555 a reg as a pointer if we have REG or REG + CONST_INT. */
558 else if (GET_CODE (x) == REG)
559 mark_reg_pointer (x, 1);
560 else if (GET_CODE (x) == PLUS
561 && GET_CODE (XEXP (x, 0)) == REG
562 && GET_CODE (XEXP (x, 1)) == CONST_INT)
563 mark_reg_pointer (XEXP (x, 0), 1);
565 /* OLDX may have been the address on a temporary. Update the address
566 to indicate that X is now used. */
567 update_temp_slot_address (oldx, x);
572 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
575 memory_address_noforce (mode, x)
576 enum machine_mode mode;
579 int ambient_force_addr = flag_force_addr;
583 val = memory_address (mode, x);
584 flag_force_addr = ambient_force_addr;
588 /* Convert a mem ref into one with a valid memory address.
589 Pass through anything else unchanged. */
595 if (GET_CODE (ref) != MEM)
597 if (memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
599 /* Don't alter REF itself, since that is probably a stack slot. */
600 return change_address (ref, GET_MODE (ref), XEXP (ref, 0));
603 /* Return a modified copy of X with its memory address copied
604 into a temporary register to protect it from side effects.
605 If X is not a MEM, it is returned unchanged (and not copied).
606 Perhaps even if it is a MEM, if there is no need to change it. */
613 if (GET_CODE (x) != MEM)
616 if (rtx_unstable_p (addr))
618 rtx temp = copy_all_regs (addr);
620 if (GET_CODE (temp) != REG)
621 temp = copy_to_reg (temp);
622 mem = gen_rtx_MEM (GET_MODE (x), temp);
624 /* Mark returned memref with in_struct if it's in an array or
625 structure. Copy const and volatile from original memref. */
627 RTX_UNCHANGING_P (mem) = RTX_UNCHANGING_P (x);
628 MEM_COPY_ATTRIBUTES (mem, x);
629 if (GET_CODE (addr) == PLUS)
630 MEM_SET_IN_STRUCT_P (mem, 1);
632 /* Since the new MEM is just like the old X, it can alias only
633 the things that X could. */
634 MEM_ALIAS_SET (mem) = MEM_ALIAS_SET (x);
641 /* Copy the value or contents of X to a new temp reg and return that reg. */
647 register rtx temp = gen_reg_rtx (GET_MODE (x));
649 /* If not an operand, must be an address with PLUS and MULT so
650 do the computation. */
651 if (! general_operand (x, VOIDmode))
652 x = force_operand (x, temp);
655 emit_move_insn (temp, x);
660 /* Like copy_to_reg but always give the new register mode Pmode
661 in case X is a constant. */
667 return copy_to_mode_reg (Pmode, x);
670 /* Like copy_to_reg but always give the new register mode MODE
671 in case X is a constant. */
674 copy_to_mode_reg (mode, x)
675 enum machine_mode mode;
678 register rtx temp = gen_reg_rtx (mode);
680 /* If not an operand, must be an address with PLUS and MULT so
681 do the computation. */
682 if (! general_operand (x, VOIDmode))
683 x = force_operand (x, temp);
685 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
688 emit_move_insn (temp, x);
692 /* Load X into a register if it is not already one.
693 Use mode MODE for the register.
694 X should be valid for mode MODE, but it may be a constant which
695 is valid for all integer modes; that's why caller must specify MODE.
697 The caller must not alter the value in the register we return,
698 since we mark it as a "constant" register. */
702 enum machine_mode mode;
705 register rtx temp, insn, set;
707 if (GET_CODE (x) == REG)
709 temp = gen_reg_rtx (mode);
710 insn = emit_move_insn (temp, x);
712 /* Let optimizers know that TEMP's value never changes
713 and that X can be substituted for it. Don't get confused
714 if INSN set something else (such as a SUBREG of TEMP). */
716 && (set = single_set (insn)) != 0
717 && SET_DEST (set) == temp)
719 rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
724 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EQUAL, x, REG_NOTES (insn));
729 /* If X is a memory ref, copy its contents to a new temp reg and return
730 that reg. Otherwise, return X. */
737 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode)
739 temp = gen_reg_rtx (GET_MODE (x));
740 emit_move_insn (temp, x);
744 /* Copy X to TARGET (if it's nonzero and a reg)
745 or to a new temp reg and return that reg.
746 MODE is the mode to use for X in case it is a constant. */
749 copy_to_suggested_reg (x, target, mode)
751 enum machine_mode mode;
755 if (target && GET_CODE (target) == REG)
758 temp = gen_reg_rtx (mode);
760 emit_move_insn (temp, x);
764 /* Return the mode to use to store a scalar of TYPE and MODE.
765 PUNSIGNEDP points to the signedness of the type and may be adjusted
766 to show what signedness to use on extension operations.
768 FOR_CALL is non-zero if this call is promoting args for a call. */
771 promote_mode (type, mode, punsignedp, for_call)
773 enum machine_mode mode;
775 int for_call ATTRIBUTE_UNUSED;
777 enum tree_code code = TREE_CODE (type);
778 int unsignedp = *punsignedp;
780 #ifdef PROMOTE_FOR_CALL_ONLY
788 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
789 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
790 PROMOTE_MODE (mode, unsignedp, type);
794 #ifdef POINTERS_EXTEND_UNSIGNED
798 unsignedp = POINTERS_EXTEND_UNSIGNED;
806 *punsignedp = unsignedp;
810 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
811 This pops when ADJUST is positive. ADJUST need not be constant. */
814 adjust_stack (adjust)
818 adjust = protect_from_queue (adjust, 0);
820 if (adjust == const0_rtx)
823 temp = expand_binop (Pmode,
824 #ifdef STACK_GROWS_DOWNWARD
829 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
832 if (temp != stack_pointer_rtx)
833 emit_move_insn (stack_pointer_rtx, temp);
836 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
837 This pushes when ADJUST is positive. ADJUST need not be constant. */
840 anti_adjust_stack (adjust)
844 adjust = protect_from_queue (adjust, 0);
846 if (adjust == const0_rtx)
849 temp = expand_binop (Pmode,
850 #ifdef STACK_GROWS_DOWNWARD
855 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
858 if (temp != stack_pointer_rtx)
859 emit_move_insn (stack_pointer_rtx, temp);
862 /* Round the size of a block to be pushed up to the boundary required
863 by this machine. SIZE is the desired size, which need not be constant. */
869 #ifdef PREFERRED_STACK_BOUNDARY
870 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
873 if (GET_CODE (size) == CONST_INT)
875 int new = (INTVAL (size) + align - 1) / align * align;
876 if (INTVAL (size) != new)
877 size = GEN_INT (new);
881 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
882 but we know it can't. So add ourselves and then do
884 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
885 NULL_RTX, 1, OPTAB_LIB_WIDEN);
886 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
888 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
890 #endif /* PREFERRED_STACK_BOUNDARY */
894 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
895 to a previously-created save area. If no save area has been allocated,
896 this function will allocate one. If a save area is specified, it
897 must be of the proper mode.
899 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
900 are emitted at the current position. */
903 emit_stack_save (save_level, psave, after)
904 enum save_level save_level;
909 /* The default is that we use a move insn and save in a Pmode object. */
910 rtx (*fcn) PROTO ((rtx, rtx)) = gen_move_insn;
911 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
913 /* See if this machine has anything special to do for this kind of save. */
916 #ifdef HAVE_save_stack_block
918 if (HAVE_save_stack_block)
919 fcn = gen_save_stack_block;
922 #ifdef HAVE_save_stack_function
924 if (HAVE_save_stack_function)
925 fcn = gen_save_stack_function;
928 #ifdef HAVE_save_stack_nonlocal
930 if (HAVE_save_stack_nonlocal)
931 fcn = gen_save_stack_nonlocal;
938 /* If there is no save area and we have to allocate one, do so. Otherwise
939 verify the save area is the proper mode. */
943 if (mode != VOIDmode)
945 if (save_level == SAVE_NONLOCAL)
946 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
948 *psave = sa = gen_reg_rtx (mode);
953 if (mode == VOIDmode || GET_MODE (sa) != mode)
962 /* We must validize inside the sequence, to ensure that any instructions
963 created by the validize call also get moved to the right place. */
965 sa = validize_mem (sa);
966 emit_insn (fcn (sa, stack_pointer_rtx));
967 seq = gen_sequence ();
969 emit_insn_after (seq, after);
974 sa = validize_mem (sa);
975 emit_insn (fcn (sa, stack_pointer_rtx));
979 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
980 area made by emit_stack_save. If it is zero, we have nothing to do.
982 Put any emitted insns after insn AFTER, if nonzero, otherwise at
986 emit_stack_restore (save_level, sa, after)
987 enum save_level save_level;
991 /* The default is that we use a move insn. */
992 rtx (*fcn) PROTO ((rtx, rtx)) = gen_move_insn;
994 /* See if this machine has anything special to do for this kind of save. */
997 #ifdef HAVE_restore_stack_block
999 if (HAVE_restore_stack_block)
1000 fcn = gen_restore_stack_block;
1003 #ifdef HAVE_restore_stack_function
1005 if (HAVE_restore_stack_function)
1006 fcn = gen_restore_stack_function;
1009 #ifdef HAVE_restore_stack_nonlocal
1011 if (HAVE_restore_stack_nonlocal)
1012 fcn = gen_restore_stack_nonlocal;
1020 sa = validize_mem (sa);
1027 emit_insn (fcn (stack_pointer_rtx, sa));
1028 seq = gen_sequence ();
1030 emit_insn_after (seq, after);
1033 emit_insn (fcn (stack_pointer_rtx, sa));
1036 #ifdef SETJMP_VIA_SAVE_AREA
1037 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1038 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1039 platforms, the dynamic stack space used can corrupt the original
1040 frame, thus causing a crash if a longjmp unwinds to it. */
1043 optimize_save_area_alloca (insns)
1048 for (insn = insns; insn; insn = NEXT_INSN(insn))
1052 if (GET_CODE (insn) != INSN)
1055 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1057 if (REG_NOTE_KIND (note) != REG_SAVE_AREA)
1060 if (!current_function_calls_setjmp)
1062 rtx pat = PATTERN (insn);
1064 /* If we do not see the note in a pattern matching
1065 these precise characteristics, we did something
1066 entirely wrong in allocate_dynamic_stack_space.
1068 Note, one way this could happen is if SETJMP_VIA_SAVE_AREA
1069 was defined on a machine where stacks grow towards higher
1072 Right now only supported port with stack that grow upward
1073 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1074 if (GET_CODE (pat) != SET
1075 || SET_DEST (pat) != stack_pointer_rtx
1076 || GET_CODE (SET_SRC (pat)) != MINUS
1077 || XEXP (SET_SRC (pat), 0) != stack_pointer_rtx)
1080 /* This will now be transformed into a (set REG REG)
1081 so we can just blow away all the other notes. */
1082 XEXP (SET_SRC (pat), 1) = XEXP (note, 0);
1083 REG_NOTES (insn) = NULL_RTX;
1087 /* setjmp was called, we must remove the REG_SAVE_AREA
1088 note so that later passes do not get confused by its
1090 if (note == REG_NOTES (insn))
1092 REG_NOTES (insn) = XEXP (note, 1);
1098 for (srch = REG_NOTES (insn); srch; srch = XEXP (srch, 1))
1099 if (XEXP (srch, 1) == note)
1102 if (srch == NULL_RTX)
1105 XEXP (srch, 1) = XEXP (note, 1);
1108 /* Once we've seen the note of interest, we need not look at
1109 the rest of them. */
1114 #endif /* SETJMP_VIA_SAVE_AREA */
1116 /* Return an rtx representing the address of an area of memory dynamically
1117 pushed on the stack. This region of memory is always aligned to
1118 a multiple of BIGGEST_ALIGNMENT.
1120 Any required stack pointer alignment is preserved.
1122 SIZE is an rtx representing the size of the area.
1123 TARGET is a place in which the address can be placed.
1125 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1128 allocate_dynamic_stack_space (size, target, known_align)
1133 #ifdef SETJMP_VIA_SAVE_AREA
1134 rtx setjmpless_size = NULL_RTX;
1137 /* If we're asking for zero bytes, it doesn't matter what we point
1138 to since we can't dereference it. But return a reasonable
1140 if (size == const0_rtx)
1141 return virtual_stack_dynamic_rtx;
1143 /* Otherwise, show we're calling alloca or equivalent. */
1144 current_function_calls_alloca = 1;
1146 /* Ensure the size is in the proper mode. */
1147 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1148 size = convert_to_mode (Pmode, size, 1);
1150 /* We will need to ensure that the address we return is aligned to
1151 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1152 always know its final value at this point in the compilation (it
1153 might depend on the size of the outgoing parameter lists, for
1154 example), so we must align the value to be returned in that case.
1155 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if
1156 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1157 We must also do an alignment operation on the returned value if
1158 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1160 If we have to align, we must leave space in SIZE for the hole
1161 that might result from the alignment operation. */
1163 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) || ! defined (PREFERRED_STACK_BOUNDARY)
1164 #define MUST_ALIGN 1
1166 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1171 if (GET_CODE (size) == CONST_INT)
1172 size = GEN_INT (INTVAL (size)
1173 + (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1));
1175 size = expand_binop (Pmode, add_optab, size,
1176 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1177 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1180 #ifdef SETJMP_VIA_SAVE_AREA
1181 /* If setjmp restores regs from a save area in the stack frame,
1182 avoid clobbering the reg save area. Note that the offset of
1183 virtual_incoming_args_rtx includes the preallocated stack args space.
1184 It would be no problem to clobber that, but it's on the wrong side
1185 of the old save area. */
1188 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1189 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1191 if (!current_function_calls_setjmp)
1193 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1195 /* See optimize_save_area_alloca to understand what is being
1198 #if !defined(PREFERRED_STACK_BOUNDARY) || !defined(MUST_ALIGN) || (PREFERRED_STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1199 /* If anyone creates a target with these characteristics, let them
1200 know that our optimization cannot work correctly in such a case. */
1204 if (GET_CODE (size) == CONST_INT)
1206 int new = INTVAL (size) / align * align;
1208 if (INTVAL (size) != new)
1209 setjmpless_size = GEN_INT (new);
1211 setjmpless_size = size;
1215 /* Since we know overflow is not possible, we avoid using
1216 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1217 setjmpless_size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1218 GEN_INT (align), NULL_RTX, 1);
1219 setjmpless_size = expand_mult (Pmode, setjmpless_size,
1220 GEN_INT (align), NULL_RTX, 1);
1222 /* Our optimization works based upon being able to perform a simple
1223 transformation of this RTL into a (set REG REG) so make sure things
1224 did in fact end up in a REG. */
1225 if (!register_operand (setjmpless_size, Pmode))
1226 setjmpless_size = force_reg (Pmode, setjmpless_size);
1229 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1230 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1232 #endif /* SETJMP_VIA_SAVE_AREA */
1234 /* Round the size to a multiple of the required stack alignment.
1235 Since the stack if presumed to be rounded before this allocation,
1236 this will maintain the required alignment.
1238 If the stack grows downward, we could save an insn by subtracting
1239 SIZE from the stack pointer and then aligning the stack pointer.
1240 The problem with this is that the stack pointer may be unaligned
1241 between the execution of the subtraction and alignment insns and
1242 some machines do not allow this. Even on those that do, some
1243 signal handlers malfunction if a signal should occur between those
1244 insns. Since this is an extremely rare event, we have no reliable
1245 way of knowing which systems have this problem. So we avoid even
1246 momentarily mis-aligning the stack. */
1248 #ifdef PREFERRED_STACK_BOUNDARY
1249 /* If we added a variable amount to SIZE,
1250 we can no longer assume it is aligned. */
1251 #if !defined (SETJMP_VIA_SAVE_AREA)
1252 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1254 size = round_push (size);
1257 do_pending_stack_adjust ();
1259 /* If needed, check that we have the required amount of stack. Take into
1260 account what has already been checked. */
1261 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1262 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1264 /* Don't use a TARGET that isn't a pseudo. */
1265 if (target == 0 || GET_CODE (target) != REG
1266 || REGNO (target) < FIRST_PSEUDO_REGISTER)
1267 target = gen_reg_rtx (Pmode);
1269 mark_reg_pointer (target, known_align / BITS_PER_UNIT);
1271 /* Perform the required allocation from the stack. Some systems do
1272 this differently than simply incrementing/decrementing from the
1273 stack pointer, such as acquiring the space by calling malloc(). */
1274 #ifdef HAVE_allocate_stack
1275 if (HAVE_allocate_stack)
1277 enum machine_mode mode = STACK_SIZE_MODE;
1279 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][0]
1280 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][0])
1282 #ifdef POINTERS_EXTEND_UNSIGNED
1283 target = convert_memory_address (Pmode, target);
1285 target = copy_to_mode_reg (Pmode, target);
1287 size = convert_modes (mode, ptr_mode, size, 1);
1288 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][1]
1289 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][1])
1291 size = copy_to_mode_reg (mode, size);
1293 emit_insn (gen_allocate_stack (target, size));
1298 #ifndef STACK_GROWS_DOWNWARD
1299 emit_move_insn (target, virtual_stack_dynamic_rtx);
1301 size = convert_modes (Pmode, ptr_mode, size, 1);
1302 anti_adjust_stack (size);
1303 #ifdef SETJMP_VIA_SAVE_AREA
1304 if (setjmpless_size != NULL_RTX)
1306 rtx note_target = get_last_insn ();
1308 REG_NOTES (note_target)
1309 = gen_rtx_EXPR_LIST (REG_SAVE_AREA, setjmpless_size,
1310 REG_NOTES (note_target));
1312 #endif /* SETJMP_VIA_SAVE_AREA */
1313 #ifdef STACK_GROWS_DOWNWARD
1314 emit_move_insn (target, virtual_stack_dynamic_rtx);
1320 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1321 but we know it can't. So add ourselves and then do
1323 target = expand_binop (Pmode, add_optab, target,
1324 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1325 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1326 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1327 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1329 target = expand_mult (Pmode, target,
1330 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1334 /* Some systems require a particular insn to refer to the stack
1335 to make the pages exist. */
1338 emit_insn (gen_probe ());
1341 /* Record the new stack level for nonlocal gotos. */
1342 if (nonlocal_goto_handler_slots != 0)
1343 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
1348 /* Emit one stack probe at ADDRESS, an address within the stack. */
1351 emit_stack_probe (address)
1354 rtx memref = gen_rtx_MEM (word_mode, address);
1356 MEM_VOLATILE_P (memref) = 1;
1358 if (STACK_CHECK_PROBE_LOAD)
1359 emit_move_insn (gen_reg_rtx (word_mode), memref);
1361 emit_move_insn (memref, const0_rtx);
1364 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1365 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1366 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1367 subtract from the stack. If SIZE is constant, this is done
1368 with a fixed number of probes. Otherwise, we must make a loop. */
1370 #ifdef STACK_GROWS_DOWNWARD
1371 #define STACK_GROW_OP MINUS
1373 #define STACK_GROW_OP PLUS
1377 probe_stack_range (first, size)
1378 HOST_WIDE_INT first;
1381 /* First see if we have an insn to check the stack. Use it if so. */
1382 #ifdef HAVE_check_stack
1383 if (HAVE_check_stack)
1386 = force_operand (gen_rtx_STACK_GROW_OP (Pmode,
1388 plus_constant (size, first)),
1391 if (insn_operand_predicate[(int) CODE_FOR_check_stack][0]
1392 && ! ((*insn_operand_predicate[(int) CODE_FOR_check_stack][0])
1393 (last_address, Pmode)))
1394 last_address = copy_to_mode_reg (Pmode, last_address);
1396 emit_insn (gen_check_stack (last_address));
1401 /* If we have to generate explicit probes, see if we have a constant
1402 small number of them to generate. If so, that's the easy case. */
1403 if (GET_CODE (size) == CONST_INT
1404 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1406 HOST_WIDE_INT offset;
1408 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1409 for values of N from 1 until it exceeds LAST. If only one
1410 probe is needed, this will not generate any code. Then probe
1412 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1413 offset < INTVAL (size);
1414 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1415 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1419 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1421 plus_constant (size, first)));
1424 /* In the variable case, do the same as above, but in a loop. We emit loop
1425 notes so that loop optimization can be done. */
1429 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1431 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1434 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1436 plus_constant (size, first)),
1438 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1439 rtx loop_lab = gen_label_rtx ();
1440 rtx test_lab = gen_label_rtx ();
1441 rtx end_lab = gen_label_rtx ();
1444 if (GET_CODE (test_addr) != REG
1445 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1446 test_addr = force_reg (Pmode, test_addr);
1448 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
1449 emit_jump (test_lab);
1451 emit_label (loop_lab);
1452 emit_stack_probe (test_addr);
1454 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
1456 #ifdef STACK_GROWS_DOWNWARD
1457 #define CMP_OPCODE GTU
1458 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1461 #define CMP_OPCODE LTU
1462 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1466 if (temp != test_addr)
1469 emit_label (test_lab);
1470 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1471 NULL_RTX, Pmode, 1, 0, loop_lab);
1472 emit_jump (end_lab);
1473 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
1474 emit_label (end_lab);
1476 /* If will be doing stupid optimization, show test_addr is still live. */
1478 emit_insn (gen_rtx_USE (VOIDmode, test_addr));
1480 emit_stack_probe (last_addr);
1484 /* Return an rtx representing the register or memory location
1485 in which a scalar value of data type VALTYPE
1486 was returned by a function call to function FUNC.
1487 FUNC is a FUNCTION_DECL node if the precise function is known,
1491 hard_function_value (valtype, func)
1493 tree func ATTRIBUTE_UNUSED;
1495 rtx val = FUNCTION_VALUE (valtype, func);
1496 if (GET_CODE (val) == REG
1497 && GET_MODE (val) == BLKmode)
1499 int bytes = int_size_in_bytes (valtype);
1500 enum machine_mode tmpmode;
1501 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1502 tmpmode != MAX_MACHINE_MODE;
1503 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1505 /* Have we found a large enough mode? */
1506 if (GET_MODE_SIZE (tmpmode) >= bytes)
1510 /* No suitable mode found. */
1511 if (tmpmode == MAX_MACHINE_MODE)
1514 PUT_MODE (val, tmpmode);
1519 /* Return an rtx representing the register or memory location
1520 in which a scalar value of mode MODE was returned by a library call. */
1523 hard_libcall_value (mode)
1524 enum machine_mode mode;
1526 return LIBCALL_VALUE (mode);
1529 /* Look up the tree code for a given rtx code
1530 to provide the arithmetic operation for REAL_ARITHMETIC.
1531 The function returns an int because the caller may not know
1532 what `enum tree_code' means. */
1535 rtx_to_tree_code (code)
1538 enum tree_code tcode;
1561 tcode = LAST_AND_UNUSED_TREE_CODE;
1564 return ((int) tcode);