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. */
28 #include "hard-reg-set.h"
29 #include "insn-config.h"
31 #include "insn-flags.h"
32 #include "insn-codes.h"
34 #if !defined PREFERRED_STACK_BOUNDARY && defined STACK_BOUNDARY
35 #define PREFERRED_STACK_BOUNDARY STACK_BOUNDARY
38 static rtx break_out_memory_refs PROTO((rtx));
39 static void emit_stack_probe PROTO((rtx));
40 /* Return an rtx for the sum of X and the integer C.
42 This function should be used via the `plus_constant' macro. */
45 plus_constant_wide (x, c)
47 register HOST_WIDE_INT c;
49 register RTX_CODE code;
50 register enum machine_mode mode;
64 return GEN_INT (INTVAL (x) + c);
68 HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
69 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
71 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
74 add_double (l1, h1, l2, h2, &lv, &hv);
76 return immed_double_const (lv, hv, VOIDmode);
80 /* If this is a reference to the constant pool, try replacing it with
81 a reference to a new constant. If the resulting address isn't
82 valid, don't return it because we have no way to validize it. */
83 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
84 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
86 /* Any rtl we create here must go in a saveable obstack, since
87 we might have been called from within combine. */
88 push_obstacks_nochange ();
89 rtl_in_saveable_obstack ();
91 = force_const_mem (GET_MODE (x),
92 plus_constant (get_pool_constant (XEXP (x, 0)),
95 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
101 /* If adding to something entirely constant, set a flag
102 so that we can add a CONST around the result. */
113 /* The interesting case is adding the integer to a sum.
114 Look for constant term in the sum and combine
115 with C. For an integer constant term, we make a combined
116 integer. For a constant term that is not an explicit integer,
117 we cannot really combine, but group them together anyway.
119 Restart or use a recursive call in case the remaining operand is
120 something that we handle specially, such as a SYMBOL_REF.
122 We may not immediately return from the recursive call here, lest
123 all_constant gets lost. */
125 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
127 c += INTVAL (XEXP (x, 1));
131 else if (CONSTANT_P (XEXP (x, 0)))
133 x = gen_rtx_PLUS (mode,
134 plus_constant (XEXP (x, 0), c),
138 else if (CONSTANT_P (XEXP (x, 1)))
140 x = gen_rtx_PLUS (mode,
142 plus_constant (XEXP (x, 1), c));
152 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
154 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
156 else if (all_constant)
157 return gen_rtx_CONST (mode, x);
162 /* This is the same as `plus_constant', except that it handles LO_SUM.
164 This function should be used via the `plus_constant_for_output' macro. */
167 plus_constant_for_output_wide (x, c)
169 register HOST_WIDE_INT c;
171 register enum machine_mode mode = GET_MODE (x);
173 if (GET_CODE (x) == LO_SUM)
174 return gen_rtx_LO_SUM (mode, XEXP (x, 0),
175 plus_constant_for_output (XEXP (x, 1), c));
178 return plus_constant (x, c);
181 /* If X is a sum, return a new sum like X but lacking any constant terms.
182 Add all the removed constant terms into *CONSTPTR.
183 X itself is not altered. The result != X if and only if
184 it is not isomorphic to X. */
187 eliminate_constant_term (x, constptr)
194 if (GET_CODE (x) != PLUS)
197 /* First handle constants appearing at this level explicitly. */
198 if (GET_CODE (XEXP (x, 1)) == CONST_INT
199 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
201 && GET_CODE (tem) == CONST_INT)
204 return eliminate_constant_term (XEXP (x, 0), constptr);
208 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
209 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
210 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
211 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
213 && GET_CODE (tem) == CONST_INT)
216 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
222 /* Returns the insn that next references REG after INSN, or 0
223 if REG is clobbered before next referenced or we cannot find
224 an insn that references REG in a straight-line piece of code. */
227 find_next_ref (reg, insn)
233 for (insn = NEXT_INSN (insn); insn; insn = next)
235 next = NEXT_INSN (insn);
236 if (GET_CODE (insn) == NOTE)
238 if (GET_CODE (insn) == CODE_LABEL
239 || GET_CODE (insn) == BARRIER)
241 if (GET_CODE (insn) == INSN
242 || GET_CODE (insn) == JUMP_INSN
243 || GET_CODE (insn) == CALL_INSN)
245 if (reg_set_p (reg, insn))
247 if (reg_mentioned_p (reg, PATTERN (insn)))
249 if (GET_CODE (insn) == JUMP_INSN)
251 if (simplejump_p (insn))
252 next = JUMP_LABEL (insn);
256 if (GET_CODE (insn) == CALL_INSN
257 && REGNO (reg) < FIRST_PSEUDO_REGISTER
258 && call_used_regs[REGNO (reg)])
267 /* Return an rtx for the size in bytes of the value of EXP. */
273 tree size = size_in_bytes (TREE_TYPE (exp));
275 if (TREE_CODE (size) != INTEGER_CST
276 && contains_placeholder_p (size))
277 size = build (WITH_RECORD_EXPR, sizetype, size, exp);
279 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype),
280 EXPAND_MEMORY_USE_BAD);
283 /* Return a copy of X in which all memory references
284 and all constants that involve symbol refs
285 have been replaced with new temporary registers.
286 Also emit code to load the memory locations and constants
287 into those registers.
289 If X contains no such constants or memory references,
290 X itself (not a copy) is returned.
292 If a constant is found in the address that is not a legitimate constant
293 in an insn, it is left alone in the hope that it might be valid in the
296 X may contain no arithmetic except addition, subtraction and multiplication.
297 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
300 break_out_memory_refs (x)
303 if (GET_CODE (x) == MEM
304 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
305 && GET_MODE (x) != VOIDmode))
306 x = force_reg (GET_MODE (x), x);
307 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
308 || GET_CODE (x) == MULT)
310 register rtx op0 = break_out_memory_refs (XEXP (x, 0));
311 register rtx op1 = break_out_memory_refs (XEXP (x, 1));
313 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
314 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
320 #ifdef POINTERS_EXTEND_UNSIGNED
322 /* Given X, a memory address in ptr_mode, convert it to an address
323 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
324 the fact that pointers are not allowed to overflow by commuting arithmetic
325 operations over conversions so that address arithmetic insns can be
329 convert_memory_address (to_mode, x)
330 enum machine_mode to_mode;
333 enum machine_mode from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
336 /* Here we handle some special cases. If none of them apply, fall through
337 to the default case. */
338 switch (GET_CODE (x))
345 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
346 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
350 temp = gen_rtx_SYMBOL_REF (to_mode, XSTR (x, 0));
351 SYMBOL_REF_FLAG (temp) = SYMBOL_REF_FLAG (x);
352 CONSTANT_POOL_ADDRESS_P (temp) = CONSTANT_POOL_ADDRESS_P (x);
356 return gen_rtx_CONST (to_mode,
357 convert_memory_address (to_mode, XEXP (x, 0)));
361 /* For addition the second operand is a small constant, we can safely
362 permute the conversion and addition operation. We can always safely
363 permute them if we are making the address narrower. In addition,
364 always permute the operations if this is a constant. */
365 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
366 || (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 1)) == CONST_INT
367 && (INTVAL (XEXP (x, 1)) + 20000 < 40000
368 || CONSTANT_P (XEXP (x, 0)))))
369 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
370 convert_memory_address (to_mode, XEXP (x, 0)),
371 convert_memory_address (to_mode, XEXP (x, 1)));
378 return convert_modes (to_mode, from_mode,
379 x, POINTERS_EXTEND_UNSIGNED);
383 /* Given a memory address or facsimile X, construct a new address,
384 currently equivalent, that is stable: future stores won't change it.
386 X must be composed of constants, register and memory references
387 combined with addition, subtraction and multiplication:
388 in other words, just what you can get from expand_expr if sum_ok is 1.
390 Works by making copies of all regs and memory locations used
391 by X and combining them the same way X does.
392 You could also stabilize the reference to this address
393 by copying the address to a register with copy_to_reg;
394 but then you wouldn't get indexed addressing in the reference. */
400 if (GET_CODE (x) == REG)
402 if (REGNO (x) != FRAME_POINTER_REGNUM
403 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
404 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
409 else if (GET_CODE (x) == MEM)
411 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
412 || GET_CODE (x) == MULT)
414 register rtx op0 = copy_all_regs (XEXP (x, 0));
415 register rtx op1 = copy_all_regs (XEXP (x, 1));
416 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
417 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
422 /* Return something equivalent to X but valid as a memory address
423 for something of mode MODE. When X is not itself valid, this
424 works by copying X or subexpressions of it into registers. */
427 memory_address (mode, x)
428 enum machine_mode mode;
431 register rtx oldx = x;
433 if (GET_CODE (x) == ADDRESSOF)
436 #ifdef POINTERS_EXTEND_UNSIGNED
437 if (GET_MODE (x) == ptr_mode)
438 x = convert_memory_address (Pmode, x);
441 /* By passing constant addresses thru registers
442 we get a chance to cse them. */
443 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
444 x = force_reg (Pmode, x);
446 /* Accept a QUEUED that refers to a REG
447 even though that isn't a valid address.
448 On attempting to put this in an insn we will call protect_from_queue
449 which will turn it into a REG, which is valid. */
450 else if (GET_CODE (x) == QUEUED
451 && GET_CODE (QUEUED_VAR (x)) == REG)
454 /* We get better cse by rejecting indirect addressing at this stage.
455 Let the combiner create indirect addresses where appropriate.
456 For now, generate the code so that the subexpressions useful to share
457 are visible. But not if cse won't be done! */
460 if (! cse_not_expected && GET_CODE (x) != REG)
461 x = break_out_memory_refs (x);
463 /* At this point, any valid address is accepted. */
464 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
466 /* If it was valid before but breaking out memory refs invalidated it,
467 use it the old way. */
468 if (memory_address_p (mode, oldx))
471 /* Perform machine-dependent transformations on X
472 in certain cases. This is not necessary since the code
473 below can handle all possible cases, but machine-dependent
474 transformations can make better code. */
475 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
477 /* PLUS and MULT can appear in special ways
478 as the result of attempts to make an address usable for indexing.
479 Usually they are dealt with by calling force_operand, below.
480 But a sum containing constant terms is special
481 if removing them makes the sum a valid address:
482 then we generate that address in a register
483 and index off of it. We do this because it often makes
484 shorter code, and because the addresses thus generated
485 in registers often become common subexpressions. */
486 if (GET_CODE (x) == PLUS)
488 rtx constant_term = const0_rtx;
489 rtx y = eliminate_constant_term (x, &constant_term);
490 if (constant_term == const0_rtx
491 || ! memory_address_p (mode, y))
492 x = force_operand (x, NULL_RTX);
495 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
496 if (! memory_address_p (mode, y))
497 x = force_operand (x, NULL_RTX);
503 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
504 x = force_operand (x, NULL_RTX);
506 /* If we have a register that's an invalid address,
507 it must be a hard reg of the wrong class. Copy it to a pseudo. */
508 else if (GET_CODE (x) == REG)
511 /* Last resort: copy the value to a register, since
512 the register is a valid address. */
514 x = force_reg (Pmode, x);
521 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG
522 /* Don't copy an addr via a reg if it is one of our stack slots. */
523 && ! (GET_CODE (x) == PLUS
524 && (XEXP (x, 0) == virtual_stack_vars_rtx
525 || XEXP (x, 0) == virtual_incoming_args_rtx)))
527 if (general_operand (x, Pmode))
528 x = force_reg (Pmode, x);
530 x = force_operand (x, NULL_RTX);
536 /* If we didn't change the address, we are done. Otherwise, mark
537 a reg as a pointer if we have REG or REG + CONST_INT. */
540 else if (GET_CODE (x) == REG)
541 mark_reg_pointer (x, 1);
542 else if (GET_CODE (x) == PLUS
543 && GET_CODE (XEXP (x, 0)) == REG
544 && GET_CODE (XEXP (x, 1)) == CONST_INT)
545 mark_reg_pointer (XEXP (x, 0), 1);
547 /* OLDX may have been the address on a temporary. Update the address
548 to indicate that X is now used. */
549 update_temp_slot_address (oldx, x);
554 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
557 memory_address_noforce (mode, x)
558 enum machine_mode mode;
561 int ambient_force_addr = flag_force_addr;
565 val = memory_address (mode, x);
566 flag_force_addr = ambient_force_addr;
570 /* Convert a mem ref into one with a valid memory address.
571 Pass through anything else unchanged. */
577 if (GET_CODE (ref) != MEM)
579 if (memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
581 /* Don't alter REF itself, since that is probably a stack slot. */
582 return change_address (ref, GET_MODE (ref), XEXP (ref, 0));
585 /* Return a modified copy of X with its memory address copied
586 into a temporary register to protect it from side effects.
587 If X is not a MEM, it is returned unchanged (and not copied).
588 Perhaps even if it is a MEM, if there is no need to change it. */
595 if (GET_CODE (x) != MEM)
598 if (rtx_unstable_p (addr))
600 rtx temp = copy_all_regs (addr);
602 if (GET_CODE (temp) != REG)
603 temp = copy_to_reg (temp);
604 mem = gen_rtx_MEM (GET_MODE (x), temp);
606 /* Mark returned memref with in_struct if it's in an array or
607 structure. Copy const and volatile from original memref. */
609 RTX_UNCHANGING_P (mem) = RTX_UNCHANGING_P (x);
610 MEM_COPY_ATTRIBUTES (mem, x);
611 if (GET_CODE (addr) == PLUS)
612 MEM_SET_IN_STRUCT_P (mem, 1);
614 /* Since the new MEM is just like the old X, it can alias only
615 the things that X could. */
616 MEM_ALIAS_SET (mem) = MEM_ALIAS_SET (x);
623 /* Copy the value or contents of X to a new temp reg and return that reg. */
629 register rtx temp = gen_reg_rtx (GET_MODE (x));
631 /* If not an operand, must be an address with PLUS and MULT so
632 do the computation. */
633 if (! general_operand (x, VOIDmode))
634 x = force_operand (x, temp);
637 emit_move_insn (temp, x);
642 /* Like copy_to_reg but always give the new register mode Pmode
643 in case X is a constant. */
649 return copy_to_mode_reg (Pmode, x);
652 /* Like copy_to_reg but always give the new register mode MODE
653 in case X is a constant. */
656 copy_to_mode_reg (mode, x)
657 enum machine_mode mode;
660 register rtx temp = gen_reg_rtx (mode);
662 /* If not an operand, must be an address with PLUS and MULT so
663 do the computation. */
664 if (! general_operand (x, VOIDmode))
665 x = force_operand (x, temp);
667 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
670 emit_move_insn (temp, x);
674 /* Load X into a register if it is not already one.
675 Use mode MODE for the register.
676 X should be valid for mode MODE, but it may be a constant which
677 is valid for all integer modes; that's why caller must specify MODE.
679 The caller must not alter the value in the register we return,
680 since we mark it as a "constant" register. */
684 enum machine_mode mode;
687 register rtx temp, insn, set;
689 if (GET_CODE (x) == REG)
691 temp = gen_reg_rtx (mode);
692 insn = emit_move_insn (temp, x);
694 /* Let optimizers know that TEMP's value never changes
695 and that X can be substituted for it. Don't get confused
696 if INSN set something else (such as a SUBREG of TEMP). */
698 && (set = single_set (insn)) != 0
699 && SET_DEST (set) == temp)
701 rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
706 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EQUAL, x, REG_NOTES (insn));
711 /* If X is a memory ref, copy its contents to a new temp reg and return
712 that reg. Otherwise, return X. */
719 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode)
721 temp = gen_reg_rtx (GET_MODE (x));
722 emit_move_insn (temp, x);
726 /* Copy X to TARGET (if it's nonzero and a reg)
727 or to a new temp reg and return that reg.
728 MODE is the mode to use for X in case it is a constant. */
731 copy_to_suggested_reg (x, target, mode)
733 enum machine_mode mode;
737 if (target && GET_CODE (target) == REG)
740 temp = gen_reg_rtx (mode);
742 emit_move_insn (temp, x);
746 /* Return the mode to use to store a scalar of TYPE and MODE.
747 PUNSIGNEDP points to the signedness of the type and may be adjusted
748 to show what signedness to use on extension operations.
750 FOR_CALL is non-zero if this call is promoting args for a call. */
753 promote_mode (type, mode, punsignedp, for_call)
755 enum machine_mode mode;
757 int for_call ATTRIBUTE_UNUSED;
759 enum tree_code code = TREE_CODE (type);
760 int unsignedp = *punsignedp;
762 #ifdef PROMOTE_FOR_CALL_ONLY
770 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
771 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
772 PROMOTE_MODE (mode, unsignedp, type);
776 #ifdef POINTERS_EXTEND_UNSIGNED
780 unsignedp = POINTERS_EXTEND_UNSIGNED;
788 *punsignedp = unsignedp;
792 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
793 This pops when ADJUST is positive. ADJUST need not be constant. */
796 adjust_stack (adjust)
800 adjust = protect_from_queue (adjust, 0);
802 if (adjust == const0_rtx)
805 temp = expand_binop (Pmode,
806 #ifdef STACK_GROWS_DOWNWARD
811 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
814 if (temp != stack_pointer_rtx)
815 emit_move_insn (stack_pointer_rtx, temp);
818 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
819 This pushes when ADJUST is positive. ADJUST need not be constant. */
822 anti_adjust_stack (adjust)
826 adjust = protect_from_queue (adjust, 0);
828 if (adjust == const0_rtx)
831 temp = expand_binop (Pmode,
832 #ifdef STACK_GROWS_DOWNWARD
837 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
840 if (temp != stack_pointer_rtx)
841 emit_move_insn (stack_pointer_rtx, temp);
844 /* Round the size of a block to be pushed up to the boundary required
845 by this machine. SIZE is the desired size, which need not be constant. */
851 #ifdef PREFERRED_STACK_BOUNDARY
852 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
855 if (GET_CODE (size) == CONST_INT)
857 int new = (INTVAL (size) + align - 1) / align * align;
858 if (INTVAL (size) != new)
859 size = GEN_INT (new);
863 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
864 but we know it can't. So add ourselves and then do
866 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
867 NULL_RTX, 1, OPTAB_LIB_WIDEN);
868 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
870 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
872 #endif /* PREFERRED_STACK_BOUNDARY */
876 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
877 to a previously-created save area. If no save area has been allocated,
878 this function will allocate one. If a save area is specified, it
879 must be of the proper mode.
881 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
882 are emitted at the current position. */
885 emit_stack_save (save_level, psave, after)
886 enum save_level save_level;
891 /* The default is that we use a move insn and save in a Pmode object. */
892 rtx (*fcn) PROTO ((rtx, rtx)) = gen_move_insn;
893 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
895 /* See if this machine has anything special to do for this kind of save. */
898 #ifdef HAVE_save_stack_block
900 if (HAVE_save_stack_block)
901 fcn = gen_save_stack_block;
904 #ifdef HAVE_save_stack_function
906 if (HAVE_save_stack_function)
907 fcn = gen_save_stack_function;
910 #ifdef HAVE_save_stack_nonlocal
912 if (HAVE_save_stack_nonlocal)
913 fcn = gen_save_stack_nonlocal;
920 /* If there is no save area and we have to allocate one, do so. Otherwise
921 verify the save area is the proper mode. */
925 if (mode != VOIDmode)
927 if (save_level == SAVE_NONLOCAL)
928 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
930 *psave = sa = gen_reg_rtx (mode);
935 if (mode == VOIDmode || GET_MODE (sa) != mode)
944 /* We must validize inside the sequence, to ensure that any instructions
945 created by the validize call also get moved to the right place. */
947 sa = validize_mem (sa);
948 emit_insn (fcn (sa, stack_pointer_rtx));
949 seq = gen_sequence ();
951 emit_insn_after (seq, after);
956 sa = validize_mem (sa);
957 emit_insn (fcn (sa, stack_pointer_rtx));
961 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
962 area made by emit_stack_save. If it is zero, we have nothing to do.
964 Put any emitted insns after insn AFTER, if nonzero, otherwise at
968 emit_stack_restore (save_level, sa, after)
969 enum save_level save_level;
973 /* The default is that we use a move insn. */
974 rtx (*fcn) PROTO ((rtx, rtx)) = gen_move_insn;
976 /* See if this machine has anything special to do for this kind of save. */
979 #ifdef HAVE_restore_stack_block
981 if (HAVE_restore_stack_block)
982 fcn = gen_restore_stack_block;
985 #ifdef HAVE_restore_stack_function
987 if (HAVE_restore_stack_function)
988 fcn = gen_restore_stack_function;
991 #ifdef HAVE_restore_stack_nonlocal
993 if (HAVE_restore_stack_nonlocal)
994 fcn = gen_restore_stack_nonlocal;
1002 sa = validize_mem (sa);
1009 emit_insn (fcn (stack_pointer_rtx, sa));
1010 seq = gen_sequence ();
1012 emit_insn_after (seq, after);
1015 emit_insn (fcn (stack_pointer_rtx, sa));
1018 #ifdef SETJMP_VIA_SAVE_AREA
1019 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1020 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1021 platforms, the dynamic stack space used can corrupt the original
1022 frame, thus causing a crash if a longjmp unwinds to it. */
1025 optimize_save_area_alloca (insns)
1030 for (insn = insns; insn; insn = NEXT_INSN(insn))
1034 if (GET_CODE (insn) != INSN)
1037 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1039 if (REG_NOTE_KIND (note) != REG_SAVE_AREA)
1042 if (!current_function_calls_setjmp)
1044 rtx pat = PATTERN (insn);
1046 /* If we do not see the note in a pattern matching
1047 these precise characteristics, we did something
1048 entirely wrong in allocate_dynamic_stack_space.
1050 Note, one way this could happen is if SETJMP_VIA_SAVE_AREA
1051 was defined on a machine where stacks grow towards higher
1054 Right now only supported port with stack that grow upward
1055 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1056 if (GET_CODE (pat) != SET
1057 || SET_DEST (pat) != stack_pointer_rtx
1058 || GET_CODE (SET_SRC (pat)) != MINUS
1059 || XEXP (SET_SRC (pat), 0) != stack_pointer_rtx)
1062 /* This will now be transformed into a (set REG REG)
1063 so we can just blow away all the other notes. */
1064 XEXP (SET_SRC (pat), 1) = XEXP (note, 0);
1065 REG_NOTES (insn) = NULL_RTX;
1069 /* setjmp was called, we must remove the REG_SAVE_AREA
1070 note so that later passes do not get confused by its
1072 if (note == REG_NOTES (insn))
1074 REG_NOTES (insn) = XEXP (note, 1);
1080 for (srch = REG_NOTES (insn); srch; srch = XEXP (srch, 1))
1081 if (XEXP (srch, 1) == note)
1084 if (srch == NULL_RTX)
1087 XEXP (srch, 1) = XEXP (note, 1);
1090 /* Once we've seen the note of interest, we need not look at
1091 the rest of them. */
1096 #endif /* SETJMP_VIA_SAVE_AREA */
1098 /* Return an rtx representing the address of an area of memory dynamically
1099 pushed on the stack. This region of memory is always aligned to
1100 a multiple of BIGGEST_ALIGNMENT.
1102 Any required stack pointer alignment is preserved.
1104 SIZE is an rtx representing the size of the area.
1105 TARGET is a place in which the address can be placed.
1107 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1110 allocate_dynamic_stack_space (size, target, known_align)
1115 #ifdef SETJMP_VIA_SAVE_AREA
1116 rtx setjmpless_size = NULL_RTX;
1119 /* If we're asking for zero bytes, it doesn't matter what we point
1120 to since we can't dereference it. But return a reasonable
1122 if (size == const0_rtx)
1123 return virtual_stack_dynamic_rtx;
1125 /* Otherwise, show we're calling alloca or equivalent. */
1126 current_function_calls_alloca = 1;
1128 /* Ensure the size is in the proper mode. */
1129 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1130 size = convert_to_mode (Pmode, size, 1);
1132 /* We will need to ensure that the address we return is aligned to
1133 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1134 always know its final value at this point in the compilation (it
1135 might depend on the size of the outgoing parameter lists, for
1136 example), so we must align the value to be returned in that case.
1137 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if
1138 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1139 We must also do an alignment operation on the returned value if
1140 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1142 If we have to align, we must leave space in SIZE for the hole
1143 that might result from the alignment operation. */
1145 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) || ! defined (PREFERRED_STACK_BOUNDARY)
1146 #define MUST_ALIGN 1
1148 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1153 if (GET_CODE (size) == CONST_INT)
1154 size = GEN_INT (INTVAL (size)
1155 + (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1));
1157 size = expand_binop (Pmode, add_optab, size,
1158 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1159 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1162 #ifdef SETJMP_VIA_SAVE_AREA
1163 /* If setjmp restores regs from a save area in the stack frame,
1164 avoid clobbering the reg save area. Note that the offset of
1165 virtual_incoming_args_rtx includes the preallocated stack args space.
1166 It would be no problem to clobber that, but it's on the wrong side
1167 of the old save area. */
1170 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1171 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1173 if (!current_function_calls_setjmp)
1175 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1177 /* See optimize_save_area_alloca to understand what is being
1180 #if !defined(PREFERRED_STACK_BOUNDARY) || !defined(MUST_ALIGN) || (PREFERRED_STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1181 /* If anyone creates a target with these characteristics, let them
1182 know that our optimization cannot work correctly in such a case. */
1186 if (GET_CODE (size) == CONST_INT)
1188 int new = INTVAL (size) / align * align;
1190 if (INTVAL (size) != new)
1191 setjmpless_size = GEN_INT (new);
1193 setjmpless_size = size;
1197 /* Since we know overflow is not possible, we avoid using
1198 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1199 setjmpless_size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1200 GEN_INT (align), NULL_RTX, 1);
1201 setjmpless_size = expand_mult (Pmode, setjmpless_size,
1202 GEN_INT (align), NULL_RTX, 1);
1204 /* Our optimization works based upon being able to perform a simple
1205 transformation of this RTL into a (set REG REG) so make sure things
1206 did in fact end up in a REG. */
1207 if (!register_operand (setjmpless_size, Pmode))
1208 setjmpless_size = force_reg (Pmode, setjmpless_size);
1211 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1212 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1214 #endif /* SETJMP_VIA_SAVE_AREA */
1216 /* Round the size to a multiple of the required stack alignment.
1217 Since the stack if presumed to be rounded before this allocation,
1218 this will maintain the required alignment.
1220 If the stack grows downward, we could save an insn by subtracting
1221 SIZE from the stack pointer and then aligning the stack pointer.
1222 The problem with this is that the stack pointer may be unaligned
1223 between the execution of the subtraction and alignment insns and
1224 some machines do not allow this. Even on those that do, some
1225 signal handlers malfunction if a signal should occur between those
1226 insns. Since this is an extremely rare event, we have no reliable
1227 way of knowing which systems have this problem. So we avoid even
1228 momentarily mis-aligning the stack. */
1230 #ifdef PREFERRED_STACK_BOUNDARY
1231 /* If we added a variable amount to SIZE,
1232 we can no longer assume it is aligned. */
1233 #if !defined (SETJMP_VIA_SAVE_AREA)
1234 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1236 size = round_push (size);
1239 do_pending_stack_adjust ();
1241 /* If needed, check that we have the required amount of stack. Take into
1242 account what has already been checked. */
1243 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1244 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1246 /* Don't use a TARGET that isn't a pseudo. */
1247 if (target == 0 || GET_CODE (target) != REG
1248 || REGNO (target) < FIRST_PSEUDO_REGISTER)
1249 target = gen_reg_rtx (Pmode);
1251 mark_reg_pointer (target, known_align / BITS_PER_UNIT);
1253 /* Perform the required allocation from the stack. Some systems do
1254 this differently than simply incrementing/decrementing from the
1255 stack pointer, such as acquiring the space by calling malloc(). */
1256 #ifdef HAVE_allocate_stack
1257 if (HAVE_allocate_stack)
1259 enum machine_mode mode = STACK_SIZE_MODE;
1261 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][0]
1262 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][0])
1264 #ifdef POINTERS_EXTEND_UNSIGNED
1265 target = convert_memory_address (Pmode, target);
1267 target = copy_to_mode_reg (Pmode, target);
1269 size = convert_modes (mode, ptr_mode, size, 1);
1270 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][1]
1271 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][1])
1273 size = copy_to_mode_reg (mode, size);
1275 emit_insn (gen_allocate_stack (target, size));
1280 #ifndef STACK_GROWS_DOWNWARD
1281 emit_move_insn (target, virtual_stack_dynamic_rtx);
1283 size = convert_modes (Pmode, ptr_mode, size, 1);
1284 anti_adjust_stack (size);
1285 #ifdef SETJMP_VIA_SAVE_AREA
1286 if (setjmpless_size != NULL_RTX)
1288 rtx note_target = get_last_insn ();
1290 REG_NOTES (note_target)
1291 = gen_rtx_EXPR_LIST (REG_SAVE_AREA, setjmpless_size,
1292 REG_NOTES (note_target));
1294 #endif /* SETJMP_VIA_SAVE_AREA */
1295 #ifdef STACK_GROWS_DOWNWARD
1296 emit_move_insn (target, virtual_stack_dynamic_rtx);
1302 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1303 but we know it can't. So add ourselves and then do
1305 target = expand_binop (Pmode, add_optab, target,
1306 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1307 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1308 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1309 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1311 target = expand_mult (Pmode, target,
1312 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1316 /* Some systems require a particular insn to refer to the stack
1317 to make the pages exist. */
1320 emit_insn (gen_probe ());
1323 /* Record the new stack level for nonlocal gotos. */
1324 if (nonlocal_goto_handler_slots != 0)
1325 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
1330 /* Emit one stack probe at ADDRESS, an address within the stack. */
1333 emit_stack_probe (address)
1336 rtx memref = gen_rtx_MEM (word_mode, address);
1338 MEM_VOLATILE_P (memref) = 1;
1340 if (STACK_CHECK_PROBE_LOAD)
1341 emit_move_insn (gen_reg_rtx (word_mode), memref);
1343 emit_move_insn (memref, const0_rtx);
1346 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1347 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1348 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1349 subtract from the stack. If SIZE is constant, this is done
1350 with a fixed number of probes. Otherwise, we must make a loop. */
1352 #ifdef STACK_GROWS_DOWNWARD
1353 #define STACK_GROW_OP MINUS
1355 #define STACK_GROW_OP PLUS
1359 probe_stack_range (first, size)
1360 HOST_WIDE_INT first;
1363 /* First see if we have an insn to check the stack. Use it if so. */
1364 #ifdef HAVE_check_stack
1365 if (HAVE_check_stack)
1368 = force_operand (gen_rtx_STACK_GROW_OP (Pmode,
1370 plus_constant (size, first)),
1373 if (insn_operand_predicate[(int) CODE_FOR_check_stack][0]
1374 && ! ((*insn_operand_predicate[(int) CODE_FOR_check_stack][0])
1375 (last_address, Pmode)))
1376 last_address = copy_to_mode_reg (Pmode, last_address);
1378 emit_insn (gen_check_stack (last_address));
1383 /* If we have to generate explicit probes, see if we have a constant
1384 small number of them to generate. If so, that's the easy case. */
1385 if (GET_CODE (size) == CONST_INT
1386 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1388 HOST_WIDE_INT offset;
1390 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1391 for values of N from 1 until it exceeds LAST. If only one
1392 probe is needed, this will not generate any code. Then probe
1394 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1395 offset < INTVAL (size);
1396 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1397 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1401 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1403 plus_constant (size, first)));
1406 /* In the variable case, do the same as above, but in a loop. We emit loop
1407 notes so that loop optimization can be done. */
1411 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1413 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1416 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1418 plus_constant (size, first)),
1420 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1421 rtx loop_lab = gen_label_rtx ();
1422 rtx test_lab = gen_label_rtx ();
1423 rtx end_lab = gen_label_rtx ();
1426 if (GET_CODE (test_addr) != REG
1427 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1428 test_addr = force_reg (Pmode, test_addr);
1430 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
1431 emit_jump (test_lab);
1433 emit_label (loop_lab);
1434 emit_stack_probe (test_addr);
1436 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
1438 #ifdef STACK_GROWS_DOWNWARD
1439 #define CMP_OPCODE GTU
1440 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1443 #define CMP_OPCODE LTU
1444 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1448 if (temp != test_addr)
1451 emit_label (test_lab);
1452 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1453 NULL_RTX, Pmode, 1, 0, loop_lab);
1454 emit_jump (end_lab);
1455 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
1456 emit_label (end_lab);
1458 /* If will be doing stupid optimization, show test_addr is still live. */
1460 emit_insn (gen_rtx_USE (VOIDmode, test_addr));
1462 emit_stack_probe (last_addr);
1466 /* Return an rtx representing the register or memory location
1467 in which a scalar value of data type VALTYPE
1468 was returned by a function call to function FUNC.
1469 FUNC is a FUNCTION_DECL node if the precise function is known,
1473 hard_function_value (valtype, func)
1475 tree func ATTRIBUTE_UNUSED;
1477 rtx val = FUNCTION_VALUE (valtype, func);
1478 if (GET_CODE (val) == REG
1479 && GET_MODE (val) == BLKmode)
1481 int bytes = int_size_in_bytes (valtype);
1482 enum machine_mode tmpmode;
1483 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1484 tmpmode != MAX_MACHINE_MODE;
1485 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1487 /* Have we found a large enough mode? */
1488 if (GET_MODE_SIZE (tmpmode) >= bytes)
1492 /* No suitable mode found. */
1493 if (tmpmode == MAX_MACHINE_MODE)
1496 PUT_MODE (val, tmpmode);
1501 /* Return an rtx representing the register or memory location
1502 in which a scalar value of mode MODE was returned by a library call. */
1505 hard_libcall_value (mode)
1506 enum machine_mode mode;
1508 return LIBCALL_VALUE (mode);
1511 /* Look up the tree code for a given rtx code
1512 to provide the arithmetic operation for REAL_ARITHMETIC.
1513 The function returns an int because the caller may not know
1514 what `enum tree_code' means. */
1517 rtx_to_tree_code (code)
1520 enum tree_code tcode;
1543 tcode = LAST_AND_UNUSED_TREE_CODE;
1546 return ((int) tcode);