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));
43 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
46 trunc_int_for_mode (c, mode)
48 enum machine_mode mode;
50 int width = GET_MODE_BITSIZE (mode);
52 /* We clear out all bits that don't belong in MODE, unless they and our
53 sign bit are all one. So we get either a reasonable negative
54 value or a reasonable unsigned value. */
56 if (width < HOST_BITS_PER_WIDE_INT
57 && ((c & ((HOST_WIDE_INT) (-1) << (width - 1)))
58 != ((HOST_WIDE_INT) (-1) << (width - 1))))
59 c &= ((HOST_WIDE_INT) 1 << width) - 1;
61 /* If this would be an entire word for the target, but is not for
62 the host, then sign-extend on the host so that the number will look
63 the same way on the host that it would on the target.
65 For example, when building a 64 bit alpha hosted 32 bit sparc
66 targeted compiler, then we want the 32 bit unsigned value -1 to be
67 represented as a 64 bit value -1, and not as 0x00000000ffffffff.
68 The later confuses the sparc backend. */
70 if (BITS_PER_WORD < HOST_BITS_PER_WIDE_INT
71 && BITS_PER_WORD == width
72 && (c & ((HOST_WIDE_INT) 1 << (width - 1))))
73 c |= ((HOST_WIDE_INT) (-1) << width);
78 /* Return an rtx for the sum of X and the integer C.
80 This function should be used via the `plus_constant' macro. */
83 plus_constant_wide (x, c)
85 register HOST_WIDE_INT c;
87 register RTX_CODE code;
88 register enum machine_mode mode;
102 return GEN_INT (INTVAL (x) + c);
106 HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
107 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
108 HOST_WIDE_INT l2 = c;
109 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
110 HOST_WIDE_INT lv, hv;
112 add_double (l1, h1, l2, h2, &lv, &hv);
114 return immed_double_const (lv, hv, VOIDmode);
118 /* If this is a reference to the constant pool, try replacing it with
119 a reference to a new constant. If the resulting address isn't
120 valid, don't return it because we have no way to validize it. */
121 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
122 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
124 /* Any rtl we create here must go in a saveable obstack, since
125 we might have been called from within combine. */
126 push_obstacks_nochange ();
127 rtl_in_saveable_obstack ();
129 = force_const_mem (GET_MODE (x),
130 plus_constant (get_pool_constant (XEXP (x, 0)),
133 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
139 /* If adding to something entirely constant, set a flag
140 so that we can add a CONST around the result. */
151 /* The interesting case is adding the integer to a sum.
152 Look for constant term in the sum and combine
153 with C. For an integer constant term, we make a combined
154 integer. For a constant term that is not an explicit integer,
155 we cannot really combine, but group them together anyway.
157 Restart or use a recursive call in case the remaining operand is
158 something that we handle specially, such as a SYMBOL_REF.
160 We may not immediately return from the recursive call here, lest
161 all_constant gets lost. */
163 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
165 c += INTVAL (XEXP (x, 1));
167 if (GET_MODE (x) != VOIDmode)
168 c = trunc_int_for_mode (c, GET_MODE (x));
173 else if (CONSTANT_P (XEXP (x, 0)))
175 x = gen_rtx_PLUS (mode,
176 plus_constant (XEXP (x, 0), c),
180 else if (CONSTANT_P (XEXP (x, 1)))
182 x = gen_rtx_PLUS (mode,
184 plus_constant (XEXP (x, 1), c));
194 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
196 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
198 else if (all_constant)
199 return gen_rtx_CONST (mode, x);
204 /* This is the same as `plus_constant', except that it handles LO_SUM.
206 This function should be used via the `plus_constant_for_output' macro. */
209 plus_constant_for_output_wide (x, c)
211 register HOST_WIDE_INT c;
213 register enum machine_mode mode = GET_MODE (x);
215 if (GET_CODE (x) == LO_SUM)
216 return gen_rtx_LO_SUM (mode, XEXP (x, 0),
217 plus_constant_for_output (XEXP (x, 1), c));
220 return plus_constant (x, c);
223 /* If X is a sum, return a new sum like X but lacking any constant terms.
224 Add all the removed constant terms into *CONSTPTR.
225 X itself is not altered. The result != X if and only if
226 it is not isomorphic to X. */
229 eliminate_constant_term (x, constptr)
236 if (GET_CODE (x) != PLUS)
239 /* First handle constants appearing at this level explicitly. */
240 if (GET_CODE (XEXP (x, 1)) == CONST_INT
241 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
243 && GET_CODE (tem) == CONST_INT)
246 return eliminate_constant_term (XEXP (x, 0), constptr);
250 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
251 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
252 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
253 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
255 && GET_CODE (tem) == CONST_INT)
258 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
264 /* Returns the insn that next references REG after INSN, or 0
265 if REG is clobbered before next referenced or we cannot find
266 an insn that references REG in a straight-line piece of code. */
269 find_next_ref (reg, insn)
275 for (insn = NEXT_INSN (insn); insn; insn = next)
277 next = NEXT_INSN (insn);
278 if (GET_CODE (insn) == NOTE)
280 if (GET_CODE (insn) == CODE_LABEL
281 || GET_CODE (insn) == BARRIER)
283 if (GET_CODE (insn) == INSN
284 || GET_CODE (insn) == JUMP_INSN
285 || GET_CODE (insn) == CALL_INSN)
287 if (reg_set_p (reg, insn))
289 if (reg_mentioned_p (reg, PATTERN (insn)))
291 if (GET_CODE (insn) == JUMP_INSN)
293 if (simplejump_p (insn))
294 next = JUMP_LABEL (insn);
298 if (GET_CODE (insn) == CALL_INSN
299 && REGNO (reg) < FIRST_PSEUDO_REGISTER
300 && call_used_regs[REGNO (reg)])
309 /* Return an rtx for the size in bytes of the value of EXP. */
315 tree size = size_in_bytes (TREE_TYPE (exp));
317 if (TREE_CODE (size) != INTEGER_CST
318 && contains_placeholder_p (size))
319 size = build (WITH_RECORD_EXPR, sizetype, size, exp);
321 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype),
322 EXPAND_MEMORY_USE_BAD);
325 /* Return a copy of X in which all memory references
326 and all constants that involve symbol refs
327 have been replaced with new temporary registers.
328 Also emit code to load the memory locations and constants
329 into those registers.
331 If X contains no such constants or memory references,
332 X itself (not a copy) is returned.
334 If a constant is found in the address that is not a legitimate constant
335 in an insn, it is left alone in the hope that it might be valid in the
338 X may contain no arithmetic except addition, subtraction and multiplication.
339 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
342 break_out_memory_refs (x)
345 if (GET_CODE (x) == MEM
346 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
347 && GET_MODE (x) != VOIDmode))
348 x = force_reg (GET_MODE (x), x);
349 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
350 || GET_CODE (x) == MULT)
352 register rtx op0 = break_out_memory_refs (XEXP (x, 0));
353 register rtx op1 = break_out_memory_refs (XEXP (x, 1));
355 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
356 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
362 #ifdef POINTERS_EXTEND_UNSIGNED
364 /* Given X, a memory address in ptr_mode, convert it to an address
365 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
366 the fact that pointers are not allowed to overflow by commuting arithmetic
367 operations over conversions so that address arithmetic insns can be
371 convert_memory_address (to_mode, x)
372 enum machine_mode to_mode;
375 enum machine_mode from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
378 /* Here we handle some special cases. If none of them apply, fall through
379 to the default case. */
380 switch (GET_CODE (x))
387 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
388 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
392 temp = gen_rtx_SYMBOL_REF (to_mode, XSTR (x, 0));
393 SYMBOL_REF_FLAG (temp) = SYMBOL_REF_FLAG (x);
394 CONSTANT_POOL_ADDRESS_P (temp) = CONSTANT_POOL_ADDRESS_P (x);
398 return gen_rtx_CONST (to_mode,
399 convert_memory_address (to_mode, XEXP (x, 0)));
403 /* For addition the second operand is a small constant, we can safely
404 permute the conversion and addition operation. We can always safely
405 permute them if we are making the address narrower. In addition,
406 always permute the operations if this is a constant. */
407 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
408 || (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 1)) == CONST_INT
409 && (INTVAL (XEXP (x, 1)) + 20000 < 40000
410 || CONSTANT_P (XEXP (x, 0)))))
411 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
412 convert_memory_address (to_mode, XEXP (x, 0)),
413 convert_memory_address (to_mode, XEXP (x, 1)));
420 return convert_modes (to_mode, from_mode,
421 x, POINTERS_EXTEND_UNSIGNED);
425 /* Given a memory address or facsimile X, construct a new address,
426 currently equivalent, that is stable: future stores won't change it.
428 X must be composed of constants, register and memory references
429 combined with addition, subtraction and multiplication:
430 in other words, just what you can get from expand_expr if sum_ok is 1.
432 Works by making copies of all regs and memory locations used
433 by X and combining them the same way X does.
434 You could also stabilize the reference to this address
435 by copying the address to a register with copy_to_reg;
436 but then you wouldn't get indexed addressing in the reference. */
442 if (GET_CODE (x) == REG)
444 if (REGNO (x) != FRAME_POINTER_REGNUM
445 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
446 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
451 else if (GET_CODE (x) == MEM)
453 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
454 || GET_CODE (x) == MULT)
456 register rtx op0 = copy_all_regs (XEXP (x, 0));
457 register rtx op1 = copy_all_regs (XEXP (x, 1));
458 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
459 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
464 /* Return something equivalent to X but valid as a memory address
465 for something of mode MODE. When X is not itself valid, this
466 works by copying X or subexpressions of it into registers. */
469 memory_address (mode, x)
470 enum machine_mode mode;
473 register rtx oldx = x;
475 if (GET_CODE (x) == ADDRESSOF)
478 #ifdef POINTERS_EXTEND_UNSIGNED
479 if (GET_MODE (x) == ptr_mode)
480 x = convert_memory_address (Pmode, x);
483 /* By passing constant addresses thru registers
484 we get a chance to cse them. */
485 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
486 x = force_reg (Pmode, x);
488 /* Accept a QUEUED that refers to a REG
489 even though that isn't a valid address.
490 On attempting to put this in an insn we will call protect_from_queue
491 which will turn it into a REG, which is valid. */
492 else if (GET_CODE (x) == QUEUED
493 && GET_CODE (QUEUED_VAR (x)) == REG)
496 /* We get better cse by rejecting indirect addressing at this stage.
497 Let the combiner create indirect addresses where appropriate.
498 For now, generate the code so that the subexpressions useful to share
499 are visible. But not if cse won't be done! */
502 if (! cse_not_expected && GET_CODE (x) != REG)
503 x = break_out_memory_refs (x);
505 /* At this point, any valid address is accepted. */
506 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
508 /* If it was valid before but breaking out memory refs invalidated it,
509 use it the old way. */
510 if (memory_address_p (mode, oldx))
513 /* Perform machine-dependent transformations on X
514 in certain cases. This is not necessary since the code
515 below can handle all possible cases, but machine-dependent
516 transformations can make better code. */
517 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
519 /* PLUS and MULT can appear in special ways
520 as the result of attempts to make an address usable for indexing.
521 Usually they are dealt with by calling force_operand, below.
522 But a sum containing constant terms is special
523 if removing them makes the sum a valid address:
524 then we generate that address in a register
525 and index off of it. We do this because it often makes
526 shorter code, and because the addresses thus generated
527 in registers often become common subexpressions. */
528 if (GET_CODE (x) == PLUS)
530 rtx constant_term = const0_rtx;
531 rtx y = eliminate_constant_term (x, &constant_term);
532 if (constant_term == const0_rtx
533 || ! memory_address_p (mode, y))
534 x = force_operand (x, NULL_RTX);
537 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
538 if (! memory_address_p (mode, y))
539 x = force_operand (x, NULL_RTX);
545 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
546 x = force_operand (x, NULL_RTX);
548 /* If we have a register that's an invalid address,
549 it must be a hard reg of the wrong class. Copy it to a pseudo. */
550 else if (GET_CODE (x) == REG)
553 /* Last resort: copy the value to a register, since
554 the register is a valid address. */
556 x = force_reg (Pmode, x);
563 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG
564 /* Don't copy an addr via a reg if it is one of our stack slots. */
565 && ! (GET_CODE (x) == PLUS
566 && (XEXP (x, 0) == virtual_stack_vars_rtx
567 || XEXP (x, 0) == virtual_incoming_args_rtx)))
569 if (general_operand (x, Pmode))
570 x = force_reg (Pmode, x);
572 x = force_operand (x, NULL_RTX);
578 /* If we didn't change the address, we are done. Otherwise, mark
579 a reg as a pointer if we have REG or REG + CONST_INT. */
582 else if (GET_CODE (x) == REG)
583 mark_reg_pointer (x, 1);
584 else if (GET_CODE (x) == PLUS
585 && GET_CODE (XEXP (x, 0)) == REG
586 && GET_CODE (XEXP (x, 1)) == CONST_INT)
587 mark_reg_pointer (XEXP (x, 0), 1);
589 /* OLDX may have been the address on a temporary. Update the address
590 to indicate that X is now used. */
591 update_temp_slot_address (oldx, x);
596 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
599 memory_address_noforce (mode, x)
600 enum machine_mode mode;
603 int ambient_force_addr = flag_force_addr;
607 val = memory_address (mode, x);
608 flag_force_addr = ambient_force_addr;
612 /* Convert a mem ref into one with a valid memory address.
613 Pass through anything else unchanged. */
619 if (GET_CODE (ref) != MEM)
621 if (memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
623 /* Don't alter REF itself, since that is probably a stack slot. */
624 return change_address (ref, GET_MODE (ref), XEXP (ref, 0));
627 /* Return a modified copy of X with its memory address copied
628 into a temporary register to protect it from side effects.
629 If X is not a MEM, it is returned unchanged (and not copied).
630 Perhaps even if it is a MEM, if there is no need to change it. */
637 if (GET_CODE (x) != MEM)
640 if (rtx_unstable_p (addr))
642 rtx temp = copy_all_regs (addr);
644 if (GET_CODE (temp) != REG)
645 temp = copy_to_reg (temp);
646 mem = gen_rtx_MEM (GET_MODE (x), temp);
648 /* Mark returned memref with in_struct if it's in an array or
649 structure. Copy const and volatile from original memref. */
651 RTX_UNCHANGING_P (mem) = RTX_UNCHANGING_P (x);
652 MEM_COPY_ATTRIBUTES (mem, x);
653 if (GET_CODE (addr) == PLUS)
654 MEM_SET_IN_STRUCT_P (mem, 1);
656 /* Since the new MEM is just like the old X, it can alias only
657 the things that X could. */
658 MEM_ALIAS_SET (mem) = MEM_ALIAS_SET (x);
665 /* Copy the value or contents of X to a new temp reg and return that reg. */
671 register rtx temp = gen_reg_rtx (GET_MODE (x));
673 /* If not an operand, must be an address with PLUS and MULT so
674 do the computation. */
675 if (! general_operand (x, VOIDmode))
676 x = force_operand (x, temp);
679 emit_move_insn (temp, x);
684 /* Like copy_to_reg but always give the new register mode Pmode
685 in case X is a constant. */
691 return copy_to_mode_reg (Pmode, x);
694 /* Like copy_to_reg but always give the new register mode MODE
695 in case X is a constant. */
698 copy_to_mode_reg (mode, x)
699 enum machine_mode mode;
702 register rtx temp = gen_reg_rtx (mode);
704 /* If not an operand, must be an address with PLUS and MULT so
705 do the computation. */
706 if (! general_operand (x, VOIDmode))
707 x = force_operand (x, temp);
709 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
712 emit_move_insn (temp, x);
716 /* Load X into a register if it is not already one.
717 Use mode MODE for the register.
718 X should be valid for mode MODE, but it may be a constant which
719 is valid for all integer modes; that's why caller must specify MODE.
721 The caller must not alter the value in the register we return,
722 since we mark it as a "constant" register. */
726 enum machine_mode mode;
729 register rtx temp, insn, set;
731 if (GET_CODE (x) == REG)
734 temp = gen_reg_rtx (mode);
736 if (! general_operand (x, mode))
737 x = force_operand (x, NULL_RTX);
739 insn = emit_move_insn (temp, x);
741 /* Let optimizers know that TEMP's value never changes
742 and that X can be substituted for it. Don't get confused
743 if INSN set something else (such as a SUBREG of TEMP). */
745 && (set = single_set (insn)) != 0
746 && SET_DEST (set) == temp)
748 rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
753 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EQUAL, x, REG_NOTES (insn));
758 /* If X is a memory ref, copy its contents to a new temp reg and return
759 that reg. Otherwise, return X. */
766 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode)
768 temp = gen_reg_rtx (GET_MODE (x));
769 emit_move_insn (temp, x);
773 /* Copy X to TARGET (if it's nonzero and a reg)
774 or to a new temp reg and return that reg.
775 MODE is the mode to use for X in case it is a constant. */
778 copy_to_suggested_reg (x, target, mode)
780 enum machine_mode mode;
784 if (target && GET_CODE (target) == REG)
787 temp = gen_reg_rtx (mode);
789 emit_move_insn (temp, x);
793 /* Return the mode to use to store a scalar of TYPE and MODE.
794 PUNSIGNEDP points to the signedness of the type and may be adjusted
795 to show what signedness to use on extension operations.
797 FOR_CALL is non-zero if this call is promoting args for a call. */
800 promote_mode (type, mode, punsignedp, for_call)
802 enum machine_mode mode;
804 int for_call ATTRIBUTE_UNUSED;
806 enum tree_code code = TREE_CODE (type);
807 int unsignedp = *punsignedp;
809 #ifdef PROMOTE_FOR_CALL_ONLY
817 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
818 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
819 PROMOTE_MODE (mode, unsignedp, type);
823 #ifdef POINTERS_EXTEND_UNSIGNED
827 unsignedp = POINTERS_EXTEND_UNSIGNED;
835 *punsignedp = unsignedp;
839 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
840 This pops when ADJUST is positive. ADJUST need not be constant. */
843 adjust_stack (adjust)
847 adjust = protect_from_queue (adjust, 0);
849 if (adjust == const0_rtx)
852 temp = expand_binop (Pmode,
853 #ifdef STACK_GROWS_DOWNWARD
858 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
861 if (temp != stack_pointer_rtx)
862 emit_move_insn (stack_pointer_rtx, temp);
865 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
866 This pushes when ADJUST is positive. ADJUST need not be constant. */
869 anti_adjust_stack (adjust)
873 adjust = protect_from_queue (adjust, 0);
875 if (adjust == const0_rtx)
878 temp = expand_binop (Pmode,
879 #ifdef STACK_GROWS_DOWNWARD
884 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
887 if (temp != stack_pointer_rtx)
888 emit_move_insn (stack_pointer_rtx, temp);
891 /* Round the size of a block to be pushed up to the boundary required
892 by this machine. SIZE is the desired size, which need not be constant. */
898 #ifdef PREFERRED_STACK_BOUNDARY
899 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
902 if (GET_CODE (size) == CONST_INT)
904 int new = (INTVAL (size) + align - 1) / align * align;
905 if (INTVAL (size) != new)
906 size = GEN_INT (new);
910 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
911 but we know it can't. So add ourselves and then do
913 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
914 NULL_RTX, 1, OPTAB_LIB_WIDEN);
915 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
917 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
919 #endif /* PREFERRED_STACK_BOUNDARY */
923 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
924 to a previously-created save area. If no save area has been allocated,
925 this function will allocate one. If a save area is specified, it
926 must be of the proper mode.
928 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
929 are emitted at the current position. */
932 emit_stack_save (save_level, psave, after)
933 enum save_level save_level;
938 /* The default is that we use a move insn and save in a Pmode object. */
939 rtx (*fcn) PROTO ((rtx, rtx)) = gen_move_insn;
940 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
942 /* See if this machine has anything special to do for this kind of save. */
945 #ifdef HAVE_save_stack_block
947 if (HAVE_save_stack_block)
948 fcn = gen_save_stack_block;
951 #ifdef HAVE_save_stack_function
953 if (HAVE_save_stack_function)
954 fcn = gen_save_stack_function;
957 #ifdef HAVE_save_stack_nonlocal
959 if (HAVE_save_stack_nonlocal)
960 fcn = gen_save_stack_nonlocal;
967 /* If there is no save area and we have to allocate one, do so. Otherwise
968 verify the save area is the proper mode. */
972 if (mode != VOIDmode)
974 if (save_level == SAVE_NONLOCAL)
975 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
977 *psave = sa = gen_reg_rtx (mode);
982 if (mode == VOIDmode || GET_MODE (sa) != mode)
991 /* We must validize inside the sequence, to ensure that any instructions
992 created by the validize call also get moved to the right place. */
994 sa = validize_mem (sa);
995 emit_insn (fcn (sa, stack_pointer_rtx));
996 seq = gen_sequence ();
998 emit_insn_after (seq, after);
1003 sa = validize_mem (sa);
1004 emit_insn (fcn (sa, stack_pointer_rtx));
1008 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1009 area made by emit_stack_save. If it is zero, we have nothing to do.
1011 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1012 current position. */
1015 emit_stack_restore (save_level, sa, after)
1016 enum save_level save_level;
1020 /* The default is that we use a move insn. */
1021 rtx (*fcn) PROTO ((rtx, rtx)) = gen_move_insn;
1023 /* See if this machine has anything special to do for this kind of save. */
1026 #ifdef HAVE_restore_stack_block
1028 if (HAVE_restore_stack_block)
1029 fcn = gen_restore_stack_block;
1032 #ifdef HAVE_restore_stack_function
1034 if (HAVE_restore_stack_function)
1035 fcn = gen_restore_stack_function;
1038 #ifdef HAVE_restore_stack_nonlocal
1040 if (HAVE_restore_stack_nonlocal)
1041 fcn = gen_restore_stack_nonlocal;
1049 sa = validize_mem (sa);
1056 emit_insn (fcn (stack_pointer_rtx, sa));
1057 seq = gen_sequence ();
1059 emit_insn_after (seq, after);
1062 emit_insn (fcn (stack_pointer_rtx, sa));
1065 #ifdef SETJMP_VIA_SAVE_AREA
1066 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1067 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1068 platforms, the dynamic stack space used can corrupt the original
1069 frame, thus causing a crash if a longjmp unwinds to it. */
1072 optimize_save_area_alloca (insns)
1077 for (insn = insns; insn; insn = NEXT_INSN(insn))
1081 if (GET_CODE (insn) != INSN)
1084 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1086 if (REG_NOTE_KIND (note) != REG_SAVE_AREA)
1089 if (!current_function_calls_setjmp)
1091 rtx pat = PATTERN (insn);
1093 /* If we do not see the note in a pattern matching
1094 these precise characteristics, we did something
1095 entirely wrong in allocate_dynamic_stack_space.
1097 Note, one way this could happen is if SETJMP_VIA_SAVE_AREA
1098 was defined on a machine where stacks grow towards higher
1101 Right now only supported port with stack that grow upward
1102 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1103 if (GET_CODE (pat) != SET
1104 || SET_DEST (pat) != stack_pointer_rtx
1105 || GET_CODE (SET_SRC (pat)) != MINUS
1106 || XEXP (SET_SRC (pat), 0) != stack_pointer_rtx)
1109 /* This will now be transformed into a (set REG REG)
1110 so we can just blow away all the other notes. */
1111 XEXP (SET_SRC (pat), 1) = XEXP (note, 0);
1112 REG_NOTES (insn) = NULL_RTX;
1116 /* setjmp was called, we must remove the REG_SAVE_AREA
1117 note so that later passes do not get confused by its
1119 if (note == REG_NOTES (insn))
1121 REG_NOTES (insn) = XEXP (note, 1);
1127 for (srch = REG_NOTES (insn); srch; srch = XEXP (srch, 1))
1128 if (XEXP (srch, 1) == note)
1131 if (srch == NULL_RTX)
1134 XEXP (srch, 1) = XEXP (note, 1);
1137 /* Once we've seen the note of interest, we need not look at
1138 the rest of them. */
1143 #endif /* SETJMP_VIA_SAVE_AREA */
1145 /* Return an rtx representing the address of an area of memory dynamically
1146 pushed on the stack. This region of memory is always aligned to
1147 a multiple of BIGGEST_ALIGNMENT.
1149 Any required stack pointer alignment is preserved.
1151 SIZE is an rtx representing the size of the area.
1152 TARGET is a place in which the address can be placed.
1154 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1157 allocate_dynamic_stack_space (size, target, known_align)
1162 #ifdef SETJMP_VIA_SAVE_AREA
1163 rtx setjmpless_size = NULL_RTX;
1166 /* If we're asking for zero bytes, it doesn't matter what we point
1167 to since we can't dereference it. But return a reasonable
1169 if (size == const0_rtx)
1170 return virtual_stack_dynamic_rtx;
1172 /* Otherwise, show we're calling alloca or equivalent. */
1173 current_function_calls_alloca = 1;
1175 /* Ensure the size is in the proper mode. */
1176 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1177 size = convert_to_mode (Pmode, size, 1);
1179 /* We will need to ensure that the address we return is aligned to
1180 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1181 always know its final value at this point in the compilation (it
1182 might depend on the size of the outgoing parameter lists, for
1183 example), so we must align the value to be returned in that case.
1184 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if
1185 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1186 We must also do an alignment operation on the returned value if
1187 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1189 If we have to align, we must leave space in SIZE for the hole
1190 that might result from the alignment operation. */
1192 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) || ! defined (PREFERRED_STACK_BOUNDARY)
1193 #define MUST_ALIGN 1
1195 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1200 if (GET_CODE (size) == CONST_INT)
1201 size = GEN_INT (INTVAL (size)
1202 + (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1));
1204 size = expand_binop (Pmode, add_optab, size,
1205 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1206 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1209 #ifdef SETJMP_VIA_SAVE_AREA
1210 /* If setjmp restores regs from a save area in the stack frame,
1211 avoid clobbering the reg save area. Note that the offset of
1212 virtual_incoming_args_rtx includes the preallocated stack args space.
1213 It would be no problem to clobber that, but it's on the wrong side
1214 of the old save area. */
1217 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1218 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1220 if (!current_function_calls_setjmp)
1222 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1224 /* See optimize_save_area_alloca to understand what is being
1227 #if !defined(PREFERRED_STACK_BOUNDARY) || !defined(MUST_ALIGN) || (PREFERRED_STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1228 /* If anyone creates a target with these characteristics, let them
1229 know that our optimization cannot work correctly in such a case. */
1233 if (GET_CODE (size) == CONST_INT)
1235 int new = INTVAL (size) / align * align;
1237 if (INTVAL (size) != new)
1238 setjmpless_size = GEN_INT (new);
1240 setjmpless_size = size;
1244 /* Since we know overflow is not possible, we avoid using
1245 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1246 setjmpless_size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1247 GEN_INT (align), NULL_RTX, 1);
1248 setjmpless_size = expand_mult (Pmode, setjmpless_size,
1249 GEN_INT (align), NULL_RTX, 1);
1251 /* Our optimization works based upon being able to perform a simple
1252 transformation of this RTL into a (set REG REG) so make sure things
1253 did in fact end up in a REG. */
1254 if (!register_operand (setjmpless_size, Pmode))
1255 setjmpless_size = force_reg (Pmode, setjmpless_size);
1258 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1259 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1261 #endif /* SETJMP_VIA_SAVE_AREA */
1263 /* Round the size to a multiple of the required stack alignment.
1264 Since the stack if presumed to be rounded before this allocation,
1265 this will maintain the required alignment.
1267 If the stack grows downward, we could save an insn by subtracting
1268 SIZE from the stack pointer and then aligning the stack pointer.
1269 The problem with this is that the stack pointer may be unaligned
1270 between the execution of the subtraction and alignment insns and
1271 some machines do not allow this. Even on those that do, some
1272 signal handlers malfunction if a signal should occur between those
1273 insns. Since this is an extremely rare event, we have no reliable
1274 way of knowing which systems have this problem. So we avoid even
1275 momentarily mis-aligning the stack. */
1277 #ifdef PREFERRED_STACK_BOUNDARY
1278 /* If we added a variable amount to SIZE,
1279 we can no longer assume it is aligned. */
1280 #if !defined (SETJMP_VIA_SAVE_AREA)
1281 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1283 size = round_push (size);
1286 do_pending_stack_adjust ();
1288 /* If needed, check that we have the required amount of stack. Take into
1289 account what has already been checked. */
1290 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1291 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1293 /* Don't use a TARGET that isn't a pseudo. */
1294 if (target == 0 || GET_CODE (target) != REG
1295 || REGNO (target) < FIRST_PSEUDO_REGISTER)
1296 target = gen_reg_rtx (Pmode);
1298 mark_reg_pointer (target, known_align / BITS_PER_UNIT);
1300 /* Perform the required allocation from the stack. Some systems do
1301 this differently than simply incrementing/decrementing from the
1302 stack pointer, such as acquiring the space by calling malloc(). */
1303 #ifdef HAVE_allocate_stack
1304 if (HAVE_allocate_stack)
1306 enum machine_mode mode = STACK_SIZE_MODE;
1308 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][0]
1309 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][0])
1311 #ifdef POINTERS_EXTEND_UNSIGNED
1312 target = convert_memory_address (Pmode, target);
1314 target = copy_to_mode_reg (Pmode, target);
1316 size = convert_modes (mode, ptr_mode, size, 1);
1317 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][1]
1318 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][1])
1320 size = copy_to_mode_reg (mode, size);
1322 emit_insn (gen_allocate_stack (target, size));
1327 #ifndef STACK_GROWS_DOWNWARD
1328 emit_move_insn (target, virtual_stack_dynamic_rtx);
1330 size = convert_modes (Pmode, ptr_mode, size, 1);
1331 anti_adjust_stack (size);
1332 #ifdef SETJMP_VIA_SAVE_AREA
1333 if (setjmpless_size != NULL_RTX)
1335 rtx note_target = get_last_insn ();
1337 REG_NOTES (note_target)
1338 = gen_rtx_EXPR_LIST (REG_SAVE_AREA, setjmpless_size,
1339 REG_NOTES (note_target));
1341 #endif /* SETJMP_VIA_SAVE_AREA */
1342 #ifdef STACK_GROWS_DOWNWARD
1343 emit_move_insn (target, virtual_stack_dynamic_rtx);
1349 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1350 but we know it can't. So add ourselves and then do
1352 target = expand_binop (Pmode, add_optab, target,
1353 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1354 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1355 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1356 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1358 target = expand_mult (Pmode, target,
1359 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1363 /* Some systems require a particular insn to refer to the stack
1364 to make the pages exist. */
1367 emit_insn (gen_probe ());
1370 /* Record the new stack level for nonlocal gotos. */
1371 if (nonlocal_goto_handler_slots != 0)
1372 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
1377 /* Emit one stack probe at ADDRESS, an address within the stack. */
1380 emit_stack_probe (address)
1383 rtx memref = gen_rtx_MEM (word_mode, address);
1385 MEM_VOLATILE_P (memref) = 1;
1387 if (STACK_CHECK_PROBE_LOAD)
1388 emit_move_insn (gen_reg_rtx (word_mode), memref);
1390 emit_move_insn (memref, const0_rtx);
1393 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1394 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1395 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1396 subtract from the stack. If SIZE is constant, this is done
1397 with a fixed number of probes. Otherwise, we must make a loop. */
1399 #ifdef STACK_GROWS_DOWNWARD
1400 #define STACK_GROW_OP MINUS
1402 #define STACK_GROW_OP PLUS
1406 probe_stack_range (first, size)
1407 HOST_WIDE_INT first;
1410 /* First see if we have an insn to check the stack. Use it if so. */
1411 #ifdef HAVE_check_stack
1412 if (HAVE_check_stack)
1415 = force_operand (gen_rtx_STACK_GROW_OP (Pmode,
1417 plus_constant (size, first)),
1420 if (insn_operand_predicate[(int) CODE_FOR_check_stack][0]
1421 && ! ((*insn_operand_predicate[(int) CODE_FOR_check_stack][0])
1422 (last_address, Pmode)))
1423 last_address = copy_to_mode_reg (Pmode, last_address);
1425 emit_insn (gen_check_stack (last_address));
1430 /* If we have to generate explicit probes, see if we have a constant
1431 small number of them to generate. If so, that's the easy case. */
1432 if (GET_CODE (size) == CONST_INT
1433 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1435 HOST_WIDE_INT offset;
1437 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1438 for values of N from 1 until it exceeds LAST. If only one
1439 probe is needed, this will not generate any code. Then probe
1441 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1442 offset < INTVAL (size);
1443 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1444 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1448 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1450 plus_constant (size, first)));
1453 /* In the variable case, do the same as above, but in a loop. We emit loop
1454 notes so that loop optimization can be done. */
1458 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1460 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1463 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1465 plus_constant (size, first)),
1467 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1468 rtx loop_lab = gen_label_rtx ();
1469 rtx test_lab = gen_label_rtx ();
1470 rtx end_lab = gen_label_rtx ();
1473 if (GET_CODE (test_addr) != REG
1474 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1475 test_addr = force_reg (Pmode, test_addr);
1477 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
1478 emit_jump (test_lab);
1480 emit_label (loop_lab);
1481 emit_stack_probe (test_addr);
1483 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
1485 #ifdef STACK_GROWS_DOWNWARD
1486 #define CMP_OPCODE GTU
1487 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1490 #define CMP_OPCODE LTU
1491 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1495 if (temp != test_addr)
1498 emit_label (test_lab);
1499 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1500 NULL_RTX, Pmode, 1, 0, loop_lab);
1501 emit_jump (end_lab);
1502 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
1503 emit_label (end_lab);
1505 /* If will be doing stupid optimization, show test_addr is still live. */
1507 emit_insn (gen_rtx_USE (VOIDmode, test_addr));
1509 emit_stack_probe (last_addr);
1513 /* Return an rtx representing the register or memory location
1514 in which a scalar value of data type VALTYPE
1515 was returned by a function call to function FUNC.
1516 FUNC is a FUNCTION_DECL node if the precise function is known,
1520 hard_function_value (valtype, func)
1522 tree func ATTRIBUTE_UNUSED;
1524 rtx val = FUNCTION_VALUE (valtype, func);
1525 if (GET_CODE (val) == REG
1526 && GET_MODE (val) == BLKmode)
1528 int bytes = int_size_in_bytes (valtype);
1529 enum machine_mode tmpmode;
1530 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1531 tmpmode != MAX_MACHINE_MODE;
1532 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1534 /* Have we found a large enough mode? */
1535 if (GET_MODE_SIZE (tmpmode) >= bytes)
1539 /* No suitable mode found. */
1540 if (tmpmode == MAX_MACHINE_MODE)
1543 PUT_MODE (val, tmpmode);
1548 /* Return an rtx representing the register or memory location
1549 in which a scalar value of mode MODE was returned by a library call. */
1552 hard_libcall_value (mode)
1553 enum machine_mode mode;
1555 return LIBCALL_VALUE (mode);
1558 /* Look up the tree code for a given rtx code
1559 to provide the arithmetic operation for REAL_ARITHMETIC.
1560 The function returns an int because the caller may not know
1561 what `enum tree_code' means. */
1564 rtx_to_tree_code (code)
1567 enum tree_code tcode;
1590 tcode = LAST_AND_UNUSED_TREE_CODE;
1593 return ((int) tcode);