1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987, 1991, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
25 #include "coretypes.h"
35 #include "hard-reg-set.h"
36 #include "insn-config.h"
39 #include "langhooks.h"
41 static rtx break_out_memory_refs (rtx);
42 static void emit_stack_probe (rtx);
45 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
48 trunc_int_for_mode (HOST_WIDE_INT c, enum machine_mode mode)
50 int width = GET_MODE_BITSIZE (mode);
52 /* You want to truncate to a _what_? */
53 if (! SCALAR_INT_MODE_P (mode))
56 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
58 return c & 1 ? STORE_FLAG_VALUE : 0;
60 /* Sign-extend for the requested mode. */
62 if (width < HOST_BITS_PER_WIDE_INT)
64 HOST_WIDE_INT sign = 1;
74 /* Return an rtx for the sum of X and the integer C. */
77 plus_constant (rtx x, HOST_WIDE_INT c)
81 enum machine_mode mode;
97 return GEN_INT (INTVAL (x) + c);
101 unsigned HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
102 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
103 unsigned HOST_WIDE_INT l2 = c;
104 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
105 unsigned HOST_WIDE_INT lv;
108 add_double (l1, h1, l2, h2, &lv, &hv);
110 return immed_double_const (lv, hv, VOIDmode);
114 /* If this is a reference to the constant pool, try replacing it with
115 a reference to a new constant. If the resulting address isn't
116 valid, don't return it because we have no way to validize it. */
117 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
118 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
121 = force_const_mem (GET_MODE (x),
122 plus_constant (get_pool_constant (XEXP (x, 0)),
124 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
130 /* If adding to something entirely constant, set a flag
131 so that we can add a CONST around the result. */
142 /* The interesting case is adding the integer to a sum.
143 Look for constant term in the sum and combine
144 with C. For an integer constant term, we make a combined
145 integer. For a constant term that is not an explicit integer,
146 we cannot really combine, but group them together anyway.
148 Restart or use a recursive call in case the remaining operand is
149 something that we handle specially, such as a SYMBOL_REF.
151 We may not immediately return from the recursive call here, lest
152 all_constant gets lost. */
154 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
156 c += INTVAL (XEXP (x, 1));
158 if (GET_MODE (x) != VOIDmode)
159 c = trunc_int_for_mode (c, GET_MODE (x));
164 else if (CONSTANT_P (XEXP (x, 1)))
166 x = gen_rtx_PLUS (mode, XEXP (x, 0), plus_constant (XEXP (x, 1), c));
169 else if (find_constant_term_loc (&y))
171 /* We need to be careful since X may be shared and we can't
172 modify it in place. */
173 rtx copy = copy_rtx (x);
174 rtx *const_loc = find_constant_term_loc (©);
176 *const_loc = plus_constant (*const_loc, c);
187 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
189 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
191 else if (all_constant)
192 return gen_rtx_CONST (mode, x);
197 /* If X is a sum, return a new sum like X but lacking any constant terms.
198 Add all the removed constant terms into *CONSTPTR.
199 X itself is not altered. The result != X if and only if
200 it is not isomorphic to X. */
203 eliminate_constant_term (rtx x, rtx *constptr)
208 if (GET_CODE (x) != PLUS)
211 /* First handle constants appearing at this level explicitly. */
212 if (GET_CODE (XEXP (x, 1)) == CONST_INT
213 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
215 && GET_CODE (tem) == CONST_INT)
218 return eliminate_constant_term (XEXP (x, 0), constptr);
222 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
223 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
224 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
225 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
227 && GET_CODE (tem) == CONST_INT)
230 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
236 /* Return an rtx for the size in bytes of the value of EXP. */
243 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
244 size = TREE_OPERAND (exp, 1);
246 size = SUBSTITUTE_PLACEHOLDER_IN_EXPR (lang_hooks.expr_size (exp), exp);
248 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), 0);
251 /* Return a wide integer for the size in bytes of the value of EXP, or -1
252 if the size can vary or is larger than an integer. */
255 int_expr_size (tree exp)
259 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
260 size = TREE_OPERAND (exp, 1);
262 size = lang_hooks.expr_size (exp);
264 if (size == 0 || !host_integerp (size, 0))
267 return tree_low_cst (size, 0);
270 /* Return a copy of X in which all memory references
271 and all constants that involve symbol refs
272 have been replaced with new temporary registers.
273 Also emit code to load the memory locations and constants
274 into those registers.
276 If X contains no such constants or memory references,
277 X itself (not a copy) is returned.
279 If a constant is found in the address that is not a legitimate constant
280 in an insn, it is left alone in the hope that it might be valid in the
283 X may contain no arithmetic except addition, subtraction and multiplication.
284 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
287 break_out_memory_refs (rtx x)
290 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
291 && GET_MODE (x) != VOIDmode))
292 x = force_reg (GET_MODE (x), x);
293 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
294 || GET_CODE (x) == MULT)
296 rtx op0 = break_out_memory_refs (XEXP (x, 0));
297 rtx op1 = break_out_memory_refs (XEXP (x, 1));
299 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
300 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
306 /* Given X, a memory address in ptr_mode, convert it to an address
307 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
308 the fact that pointers are not allowed to overflow by commuting arithmetic
309 operations over conversions so that address arithmetic insns can be
313 convert_memory_address (enum machine_mode to_mode ATTRIBUTE_UNUSED,
316 #ifndef POINTERS_EXTEND_UNSIGNED
318 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
319 enum machine_mode from_mode;
323 /* If X already has the right mode, just return it. */
324 if (GET_MODE (x) == to_mode)
327 from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
329 /* Here we handle some special cases. If none of them apply, fall through
330 to the default case. */
331 switch (GET_CODE (x))
335 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
337 else if (POINTERS_EXTEND_UNSIGNED < 0)
339 else if (POINTERS_EXTEND_UNSIGNED > 0)
343 temp = simplify_unary_operation (code, to_mode, x, from_mode);
349 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
350 && GET_MODE (SUBREG_REG (x)) == to_mode)
351 return SUBREG_REG (x);
355 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
356 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
361 temp = shallow_copy_rtx (x);
362 PUT_MODE (temp, to_mode);
367 return gen_rtx_CONST (to_mode,
368 convert_memory_address (to_mode, XEXP (x, 0)));
373 /* For addition we can safely permute the conversion and addition
374 operation if one operand is a constant and converting the constant
375 does not change it. We can always safely permute them if we are
376 making the address narrower. */
377 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
378 || (GET_CODE (x) == PLUS
379 && GET_CODE (XEXP (x, 1)) == CONST_INT
380 && XEXP (x, 1) == convert_memory_address (to_mode, XEXP (x, 1))))
381 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
382 convert_memory_address (to_mode, XEXP (x, 0)),
390 return convert_modes (to_mode, from_mode,
391 x, POINTERS_EXTEND_UNSIGNED);
392 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
395 /* Given a memory address or facsimile X, construct a new address,
396 currently equivalent, that is stable: future stores won't change it.
398 X must be composed of constants, register and memory references
399 combined with addition, subtraction and multiplication:
400 in other words, just what you can get from expand_expr if sum_ok is 1.
402 Works by making copies of all regs and memory locations used
403 by X and combining them the same way X does.
404 You could also stabilize the reference to this address
405 by copying the address to a register with copy_to_reg;
406 but then you wouldn't get indexed addressing in the reference. */
409 copy_all_regs (rtx x)
413 if (REGNO (x) != FRAME_POINTER_REGNUM
414 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
415 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
422 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
423 || GET_CODE (x) == MULT)
425 rtx op0 = copy_all_regs (XEXP (x, 0));
426 rtx op1 = copy_all_regs (XEXP (x, 1));
427 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
428 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
433 /* Return something equivalent to X but valid as a memory address
434 for something of mode MODE. When X is not itself valid, this
435 works by copying X or subexpressions of it into registers. */
438 memory_address (enum machine_mode mode, rtx x)
442 x = convert_memory_address (Pmode, x);
444 /* By passing constant addresses through 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 /* We get better cse by rejecting indirect addressing at this stage.
450 Let the combiner create indirect addresses where appropriate.
451 For now, generate the code so that the subexpressions useful to share
452 are visible. But not if cse won't be done! */
455 if (! cse_not_expected && !REG_P (x))
456 x = break_out_memory_refs (x);
458 /* At this point, any valid address is accepted. */
459 if (memory_address_p (mode, x))
462 /* If it was valid before but breaking out memory refs invalidated it,
463 use it the old way. */
464 if (memory_address_p (mode, oldx))
467 /* Perform machine-dependent transformations on X
468 in certain cases. This is not necessary since the code
469 below can handle all possible cases, but machine-dependent
470 transformations can make better code. */
471 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
473 /* PLUS and MULT can appear in special ways
474 as the result of attempts to make an address usable for indexing.
475 Usually they are dealt with by calling force_operand, below.
476 But a sum containing constant terms is special
477 if removing them makes the sum a valid address:
478 then we generate that address in a register
479 and index off of it. We do this because it often makes
480 shorter code, and because the addresses thus generated
481 in registers often become common subexpressions. */
482 if (GET_CODE (x) == PLUS)
484 rtx constant_term = const0_rtx;
485 rtx y = eliminate_constant_term (x, &constant_term);
486 if (constant_term == const0_rtx
487 || ! memory_address_p (mode, y))
488 x = force_operand (x, NULL_RTX);
491 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
492 if (! memory_address_p (mode, y))
493 x = force_operand (x, NULL_RTX);
499 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
500 x = force_operand (x, NULL_RTX);
502 /* If we have a register that's an invalid address,
503 it must be a hard reg of the wrong class. Copy it to a pseudo. */
507 /* Last resort: copy the value to a register, since
508 the register is a valid address. */
510 x = force_reg (Pmode, x);
517 if (flag_force_addr && ! cse_not_expected && !REG_P (x)
518 /* Don't copy an addr via a reg if it is one of our stack slots. */
519 && ! (GET_CODE (x) == PLUS
520 && (XEXP (x, 0) == virtual_stack_vars_rtx
521 || XEXP (x, 0) == virtual_incoming_args_rtx)))
523 if (general_operand (x, Pmode))
524 x = force_reg (Pmode, x);
526 x = force_operand (x, NULL_RTX);
532 /* If we didn't change the address, we are done. Otherwise, mark
533 a reg as a pointer if we have REG or REG + CONST_INT. */
537 mark_reg_pointer (x, BITS_PER_UNIT);
538 else if (GET_CODE (x) == PLUS
539 && REG_P (XEXP (x, 0))
540 && GET_CODE (XEXP (x, 1)) == CONST_INT)
541 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
543 /* OLDX may have been the address on a temporary. Update the address
544 to indicate that X is now used. */
545 update_temp_slot_address (oldx, x);
550 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
553 memory_address_noforce (enum machine_mode mode, rtx x)
555 int ambient_force_addr = flag_force_addr;
559 val = memory_address (mode, x);
560 flag_force_addr = ambient_force_addr;
564 /* Convert a mem ref into one with a valid memory address.
565 Pass through anything else unchanged. */
568 validize_mem (rtx ref)
572 if (! (flag_force_addr && CONSTANT_ADDRESS_P (XEXP (ref, 0)))
573 && memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
576 /* Don't alter REF itself, since that is probably a stack slot. */
577 return replace_equiv_address (ref, XEXP (ref, 0));
580 /* Given REF, either a MEM or a REG, and T, either the type of X or
581 the expression corresponding to REF, set RTX_UNCHANGING_P if
585 maybe_set_unchanging (rtx ref, tree t)
587 /* We can set RTX_UNCHANGING_P from TREE_READONLY for decls whose
588 initialization is only executed once, or whose initializer always
589 has the same value. Currently we simplify this to PARM_DECLs in the
590 first case, and decls with TREE_CONSTANT initializers in the second.
592 We cannot do this for non-static aggregates, because of the double
593 writes that can be generated by store_constructor, depending on the
594 contents of the initializer. Yes, this does eliminate a good fraction
595 of the number of uses of RTX_UNCHANGING_P for a language like Ada.
596 It also eliminates a good quantity of bugs. Let this be incentive to
597 eliminate RTX_UNCHANGING_P entirely in favor of a more reliable
598 solution, perhaps based on alias sets. */
600 if ((TREE_READONLY (t) && DECL_P (t)
601 && (TREE_STATIC (t) || ! AGGREGATE_TYPE_P (TREE_TYPE (t)))
602 && (TREE_CODE (t) == PARM_DECL
603 || (DECL_INITIAL (t) && TREE_CONSTANT (DECL_INITIAL (t)))))
604 || TREE_CODE_CLASS (TREE_CODE (t)) == 'c')
605 RTX_UNCHANGING_P (ref) = 1;
608 /* Return a modified copy of X with its memory address copied
609 into a temporary register to protect it from side effects.
610 If X is not a MEM, it is returned unchanged (and not copied).
611 Perhaps even if it is a MEM, if there is no need to change it. */
617 || ! rtx_unstable_p (XEXP (x, 0)))
621 replace_equiv_address (x, force_reg (Pmode, copy_all_regs (XEXP (x, 0))));
624 /* Copy the value or contents of X to a new temp reg and return that reg. */
629 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. */
646 copy_addr_to_reg (rtx x)
648 return copy_to_mode_reg (Pmode, x);
651 /* Like copy_to_reg but always give the new register mode MODE
652 in case X is a constant. */
655 copy_to_mode_reg (enum machine_mode mode, rtx x)
657 rtx temp = gen_reg_rtx (mode);
659 /* If not an operand, must be an address with PLUS and MULT so
660 do the computation. */
661 if (! general_operand (x, VOIDmode))
662 x = force_operand (x, temp);
664 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
667 emit_move_insn (temp, x);
671 /* Load X into a register if it is not already one.
672 Use mode MODE for the register.
673 X should be valid for mode MODE, but it may be a constant which
674 is valid for all integer modes; that's why caller must specify MODE.
676 The caller must not alter the value in the register we return,
677 since we mark it as a "constant" register. */
680 force_reg (enum machine_mode mode, rtx x)
687 if (general_operand (x, mode))
689 temp = gen_reg_rtx (mode);
690 insn = emit_move_insn (temp, x);
694 temp = force_operand (x, NULL_RTX);
696 insn = get_last_insn ();
699 rtx temp2 = gen_reg_rtx (mode);
700 insn = emit_move_insn (temp2, temp);
705 /* Let optimizers know that TEMP's value never changes
706 and that X can be substituted for it. Don't get confused
707 if INSN set something else (such as a SUBREG of TEMP). */
709 && (set = single_set (insn)) != 0
710 && SET_DEST (set) == temp
711 && ! rtx_equal_p (x, SET_SRC (set)))
712 set_unique_reg_note (insn, REG_EQUAL, x);
714 /* Let optimizers know that TEMP is a pointer, and if so, the
715 known alignment of that pointer. */
718 if (GET_CODE (x) == SYMBOL_REF)
720 align = BITS_PER_UNIT;
721 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
722 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
724 else if (GET_CODE (x) == LABEL_REF)
725 align = BITS_PER_UNIT;
726 else if (GET_CODE (x) == CONST
727 && GET_CODE (XEXP (x, 0)) == PLUS
728 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
729 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT)
731 rtx s = XEXP (XEXP (x, 0), 0);
732 rtx c = XEXP (XEXP (x, 0), 1);
736 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
737 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
739 ca = exact_log2 (INTVAL (c) & -INTVAL (c)) * BITS_PER_UNIT;
741 align = MIN (sa, ca);
745 mark_reg_pointer (temp, align);
751 /* If X is a memory ref, copy its contents to a new temp reg and return
752 that reg. Otherwise, return X. */
755 force_not_mem (rtx x)
759 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
762 temp = gen_reg_rtx (GET_MODE (x));
765 REG_POINTER (temp) = 1;
767 emit_move_insn (temp, x);
771 /* Copy X to TARGET (if it's nonzero and a reg)
772 or to a new temp reg and return that reg.
773 MODE is the mode to use for X in case it is a constant. */
776 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode)
780 if (target && REG_P (target))
783 temp = gen_reg_rtx (mode);
785 emit_move_insn (temp, x);
789 /* Return the mode to use to store a scalar of TYPE and MODE.
790 PUNSIGNEDP points to the signedness of the type and may be adjusted
791 to show what signedness to use on extension operations.
793 FOR_CALL is nonzero if this call is promoting args for a call. */
795 #if defined(PROMOTE_MODE) && !defined(PROMOTE_FUNCTION_MODE)
796 #define PROMOTE_FUNCTION_MODE PROMOTE_MODE
800 promote_mode (tree type, enum machine_mode mode, int *punsignedp,
801 int for_call ATTRIBUTE_UNUSED)
803 enum tree_code code = TREE_CODE (type);
804 int unsignedp = *punsignedp;
813 #ifdef PROMOTE_FUNCTION_MODE
814 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
815 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
820 PROMOTE_FUNCTION_MODE (mode, unsignedp, type);
825 PROMOTE_MODE (mode, unsignedp, type);
831 #ifdef POINTERS_EXTEND_UNSIGNED
835 unsignedp = POINTERS_EXTEND_UNSIGNED;
843 *punsignedp = unsignedp;
847 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
848 This pops when ADJUST is positive. ADJUST need not be constant. */
851 adjust_stack (rtx adjust)
855 if (adjust == const0_rtx)
858 /* We expect all variable sized adjustments to be multiple of
859 PREFERRED_STACK_BOUNDARY. */
860 if (GET_CODE (adjust) == CONST_INT)
861 stack_pointer_delta -= INTVAL (adjust);
863 temp = expand_binop (Pmode,
864 #ifdef STACK_GROWS_DOWNWARD
869 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
872 if (temp != stack_pointer_rtx)
873 emit_move_insn (stack_pointer_rtx, temp);
876 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
877 This pushes when ADJUST is positive. ADJUST need not be constant. */
880 anti_adjust_stack (rtx adjust)
884 if (adjust == const0_rtx)
887 /* We expect all variable sized adjustments to be multiple of
888 PREFERRED_STACK_BOUNDARY. */
889 if (GET_CODE (adjust) == CONST_INT)
890 stack_pointer_delta += INTVAL (adjust);
892 temp = expand_binop (Pmode,
893 #ifdef STACK_GROWS_DOWNWARD
898 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
901 if (temp != stack_pointer_rtx)
902 emit_move_insn (stack_pointer_rtx, temp);
905 /* Round the size of a block to be pushed up to the boundary required
906 by this machine. SIZE is the desired size, which need not be constant. */
909 round_push (rtx size)
911 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
916 if (GET_CODE (size) == CONST_INT)
918 HOST_WIDE_INT new = (INTVAL (size) + align - 1) / align * align;
920 if (INTVAL (size) != new)
921 size = GEN_INT (new);
925 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
926 but we know it can't. So add ourselves and then do
928 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
929 NULL_RTX, 1, OPTAB_LIB_WIDEN);
930 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
932 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
938 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
939 to a previously-created save area. If no save area has been allocated,
940 this function will allocate one. If a save area is specified, it
941 must be of the proper mode.
943 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
944 are emitted at the current position. */
947 emit_stack_save (enum save_level save_level, rtx *psave, rtx after)
950 /* The default is that we use a move insn and save in a Pmode object. */
951 rtx (*fcn) (rtx, rtx) = gen_move_insn;
952 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
954 /* See if this machine has anything special to do for this kind of save. */
957 #ifdef HAVE_save_stack_block
959 if (HAVE_save_stack_block)
960 fcn = gen_save_stack_block;
963 #ifdef HAVE_save_stack_function
965 if (HAVE_save_stack_function)
966 fcn = gen_save_stack_function;
969 #ifdef HAVE_save_stack_nonlocal
971 if (HAVE_save_stack_nonlocal)
972 fcn = gen_save_stack_nonlocal;
979 /* If there is no save area and we have to allocate one, do so. Otherwise
980 verify the save area is the proper mode. */
984 if (mode != VOIDmode)
986 if (save_level == SAVE_NONLOCAL)
987 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
989 *psave = sa = gen_reg_rtx (mode);
998 /* We must validize inside the sequence, to ensure that any instructions
999 created by the validize call also get moved to the right place. */
1001 sa = validize_mem (sa);
1002 emit_insn (fcn (sa, stack_pointer_rtx));
1005 emit_insn_after (seq, after);
1010 sa = validize_mem (sa);
1011 emit_insn (fcn (sa, stack_pointer_rtx));
1015 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1016 area made by emit_stack_save. If it is zero, we have nothing to do.
1018 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1019 current position. */
1022 emit_stack_restore (enum save_level save_level, rtx sa, rtx after)
1024 /* The default is that we use a move insn. */
1025 rtx (*fcn) (rtx, rtx) = gen_move_insn;
1027 /* See if this machine has anything special to do for this kind of save. */
1030 #ifdef HAVE_restore_stack_block
1032 if (HAVE_restore_stack_block)
1033 fcn = gen_restore_stack_block;
1036 #ifdef HAVE_restore_stack_function
1038 if (HAVE_restore_stack_function)
1039 fcn = gen_restore_stack_function;
1042 #ifdef HAVE_restore_stack_nonlocal
1044 if (HAVE_restore_stack_nonlocal)
1045 fcn = gen_restore_stack_nonlocal;
1054 sa = validize_mem (sa);
1055 /* These clobbers prevent the scheduler from moving
1056 references to variable arrays below the code
1057 that deletes (pops) the arrays. */
1058 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1059 gen_rtx_MEM (BLKmode,
1060 gen_rtx_SCRATCH (VOIDmode))));
1061 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1062 gen_rtx_MEM (BLKmode, stack_pointer_rtx)));
1070 emit_insn (fcn (stack_pointer_rtx, sa));
1073 emit_insn_after (seq, after);
1076 emit_insn (fcn (stack_pointer_rtx, sa));
1079 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1080 function. This function should be called whenever we allocate or
1081 deallocate dynamic stack space. */
1084 update_nonlocal_goto_save_area (void)
1089 /* The nonlocal_goto_save_area object is an array of N pointers. The
1090 first one is used for the frame pointer save; the rest are sized by
1091 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1092 of the stack save area slots. */
1093 t_save = build4 (ARRAY_REF, ptr_type_node, cfun->nonlocal_goto_save_area,
1094 integer_one_node, NULL_TREE, NULL_TREE);
1095 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1097 emit_stack_save (SAVE_NONLOCAL, &r_save, NULL_RTX);
1100 #ifdef SETJMP_VIA_SAVE_AREA
1101 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1102 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1103 platforms, the dynamic stack space used can corrupt the original
1104 frame, thus causing a crash if a longjmp unwinds to it. */
1107 optimize_save_area_alloca (void)
1111 for (insn = get_insns (); insn; insn = NEXT_INSN(insn))
1115 if (!NONJUMP_INSN_P (insn))
1118 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1120 if (REG_NOTE_KIND (note) != REG_SAVE_AREA)
1123 if (!current_function_calls_setjmp)
1125 rtx pat = PATTERN (insn);
1127 /* If we do not see the note in a pattern matching
1128 these precise characteristics, we did something
1129 entirely wrong in allocate_dynamic_stack_space.
1131 Note, one way this could happen is if SETJMP_VIA_SAVE_AREA
1132 was defined on a machine where stacks grow towards higher
1135 Right now only supported port with stack that grow upward
1136 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1137 if (GET_CODE (pat) != SET
1138 || SET_DEST (pat) != stack_pointer_rtx
1139 || GET_CODE (SET_SRC (pat)) != MINUS
1140 || XEXP (SET_SRC (pat), 0) != stack_pointer_rtx)
1143 /* This will now be transformed into a (set REG REG)
1144 so we can just blow away all the other notes. */
1145 XEXP (SET_SRC (pat), 1) = XEXP (note, 0);
1146 REG_NOTES (insn) = NULL_RTX;
1150 /* setjmp was called, we must remove the REG_SAVE_AREA
1151 note so that later passes do not get confused by its
1153 if (note == REG_NOTES (insn))
1155 REG_NOTES (insn) = XEXP (note, 1);
1161 for (srch = REG_NOTES (insn); srch; srch = XEXP (srch, 1))
1162 if (XEXP (srch, 1) == note)
1165 if (srch == NULL_RTX)
1168 XEXP (srch, 1) = XEXP (note, 1);
1171 /* Once we've seen the note of interest, we need not look at
1172 the rest of them. */
1177 #endif /* SETJMP_VIA_SAVE_AREA */
1179 /* Return an rtx representing the address of an area of memory dynamically
1180 pushed on the stack. This region of memory is always aligned to
1181 a multiple of BIGGEST_ALIGNMENT.
1183 Any required stack pointer alignment is preserved.
1185 SIZE is an rtx representing the size of the area.
1186 TARGET is a place in which the address can be placed.
1188 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1191 allocate_dynamic_stack_space (rtx size, rtx target, int known_align)
1193 #ifdef SETJMP_VIA_SAVE_AREA
1194 rtx setjmpless_size = NULL_RTX;
1197 /* If we're asking for zero bytes, it doesn't matter what we point
1198 to since we can't dereference it. But return a reasonable
1200 if (size == const0_rtx)
1201 return virtual_stack_dynamic_rtx;
1203 /* Otherwise, show we're calling alloca or equivalent. */
1204 current_function_calls_alloca = 1;
1206 /* Ensure the size is in the proper mode. */
1207 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1208 size = convert_to_mode (Pmode, size, 1);
1210 /* We can't attempt to minimize alignment necessary, because we don't
1211 know the final value of preferred_stack_boundary yet while executing
1213 cfun->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1215 /* We will need to ensure that the address we return is aligned to
1216 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1217 always know its final value at this point in the compilation (it
1218 might depend on the size of the outgoing parameter lists, for
1219 example), so we must align the value to be returned in that case.
1220 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1221 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1222 We must also do an alignment operation on the returned value if
1223 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1225 If we have to align, we must leave space in SIZE for the hole
1226 that might result from the alignment operation. */
1228 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1229 #define MUST_ALIGN 1
1231 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1236 = force_operand (plus_constant (size,
1237 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1240 #ifdef SETJMP_VIA_SAVE_AREA
1241 /* If setjmp restores regs from a save area in the stack frame,
1242 avoid clobbering the reg save area. Note that the offset of
1243 virtual_incoming_args_rtx includes the preallocated stack args space.
1244 It would be no problem to clobber that, but it's on the wrong side
1245 of the old save area. */
1248 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1249 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1251 if (!current_function_calls_setjmp)
1253 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1255 /* See optimize_save_area_alloca to understand what is being
1258 /* ??? Code below assumes that the save area needs maximal
1259 alignment. This constraint may be too strong. */
1260 if (PREFERRED_STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1263 if (GET_CODE (size) == CONST_INT)
1265 HOST_WIDE_INT new = INTVAL (size) / align * align;
1267 if (INTVAL (size) != new)
1268 setjmpless_size = GEN_INT (new);
1270 setjmpless_size = size;
1274 /* Since we know overflow is not possible, we avoid using
1275 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1276 setjmpless_size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1277 GEN_INT (align), NULL_RTX, 1);
1278 setjmpless_size = expand_mult (Pmode, setjmpless_size,
1279 GEN_INT (align), NULL_RTX, 1);
1281 /* Our optimization works based upon being able to perform a simple
1282 transformation of this RTL into a (set REG REG) so make sure things
1283 did in fact end up in a REG. */
1284 if (!register_operand (setjmpless_size, Pmode))
1285 setjmpless_size = force_reg (Pmode, setjmpless_size);
1288 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1289 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1291 #endif /* SETJMP_VIA_SAVE_AREA */
1293 /* Round the size to a multiple of the required stack alignment.
1294 Since the stack if presumed to be rounded before this allocation,
1295 this will maintain the required alignment.
1297 If the stack grows downward, we could save an insn by subtracting
1298 SIZE from the stack pointer and then aligning the stack pointer.
1299 The problem with this is that the stack pointer may be unaligned
1300 between the execution of the subtraction and alignment insns and
1301 some machines do not allow this. Even on those that do, some
1302 signal handlers malfunction if a signal should occur between those
1303 insns. Since this is an extremely rare event, we have no reliable
1304 way of knowing which systems have this problem. So we avoid even
1305 momentarily mis-aligning the stack. */
1307 /* If we added a variable amount to SIZE,
1308 we can no longer assume it is aligned. */
1309 #if !defined (SETJMP_VIA_SAVE_AREA)
1310 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1312 size = round_push (size);
1314 do_pending_stack_adjust ();
1316 /* We ought to be called always on the toplevel and stack ought to be aligned
1318 if (stack_pointer_delta % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT))
1321 /* If needed, check that we have the required amount of stack. Take into
1322 account what has already been checked. */
1323 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1324 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1326 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1327 if (target == 0 || !REG_P (target)
1328 || REGNO (target) < FIRST_PSEUDO_REGISTER
1329 || GET_MODE (target) != Pmode)
1330 target = gen_reg_rtx (Pmode);
1332 mark_reg_pointer (target, known_align);
1334 /* Perform the required allocation from the stack. Some systems do
1335 this differently than simply incrementing/decrementing from the
1336 stack pointer, such as acquiring the space by calling malloc(). */
1337 #ifdef HAVE_allocate_stack
1338 if (HAVE_allocate_stack)
1340 enum machine_mode mode = STACK_SIZE_MODE;
1341 insn_operand_predicate_fn pred;
1343 /* We don't have to check against the predicate for operand 0 since
1344 TARGET is known to be a pseudo of the proper mode, which must
1345 be valid for the operand. For operand 1, convert to the
1346 proper mode and validate. */
1347 if (mode == VOIDmode)
1348 mode = insn_data[(int) CODE_FOR_allocate_stack].operand[1].mode;
1350 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1351 if (pred && ! ((*pred) (size, mode)))
1352 size = copy_to_mode_reg (mode, convert_to_mode (mode, size, 1));
1354 emit_insn (gen_allocate_stack (target, size));
1359 #ifndef STACK_GROWS_DOWNWARD
1360 emit_move_insn (target, virtual_stack_dynamic_rtx);
1363 /* Check stack bounds if necessary. */
1364 if (current_function_limit_stack)
1367 rtx space_available = gen_label_rtx ();
1368 #ifdef STACK_GROWS_DOWNWARD
1369 available = expand_binop (Pmode, sub_optab,
1370 stack_pointer_rtx, stack_limit_rtx,
1371 NULL_RTX, 1, OPTAB_WIDEN);
1373 available = expand_binop (Pmode, sub_optab,
1374 stack_limit_rtx, stack_pointer_rtx,
1375 NULL_RTX, 1, OPTAB_WIDEN);
1377 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1381 emit_insn (gen_trap ());
1384 error ("stack limits not supported on this target");
1386 emit_label (space_available);
1389 anti_adjust_stack (size);
1390 #ifdef SETJMP_VIA_SAVE_AREA
1391 if (setjmpless_size != NULL_RTX)
1393 rtx note_target = get_last_insn ();
1395 REG_NOTES (note_target)
1396 = gen_rtx_EXPR_LIST (REG_SAVE_AREA, setjmpless_size,
1397 REG_NOTES (note_target));
1399 #endif /* SETJMP_VIA_SAVE_AREA */
1401 #ifdef STACK_GROWS_DOWNWARD
1402 emit_move_insn (target, virtual_stack_dynamic_rtx);
1408 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1409 but we know it can't. So add ourselves and then do
1411 target = expand_binop (Pmode, add_optab, target,
1412 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1413 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1414 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1415 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1417 target = expand_mult (Pmode, target,
1418 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1422 /* Record the new stack level for nonlocal gotos. */
1423 if (cfun->nonlocal_goto_save_area != 0)
1424 update_nonlocal_goto_save_area ();
1429 /* A front end may want to override GCC's stack checking by providing a
1430 run-time routine to call to check the stack, so provide a mechanism for
1431 calling that routine. */
1433 static GTY(()) rtx stack_check_libfunc;
1436 set_stack_check_libfunc (rtx libfunc)
1438 stack_check_libfunc = libfunc;
1441 /* Emit one stack probe at ADDRESS, an address within the stack. */
1444 emit_stack_probe (rtx address)
1446 rtx memref = gen_rtx_MEM (word_mode, address);
1448 MEM_VOLATILE_P (memref) = 1;
1450 if (STACK_CHECK_PROBE_LOAD)
1451 emit_move_insn (gen_reg_rtx (word_mode), memref);
1453 emit_move_insn (memref, const0_rtx);
1456 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1457 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1458 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1459 subtract from the stack. If SIZE is constant, this is done
1460 with a fixed number of probes. Otherwise, we must make a loop. */
1462 #ifdef STACK_GROWS_DOWNWARD
1463 #define STACK_GROW_OP MINUS
1465 #define STACK_GROW_OP PLUS
1469 probe_stack_range (HOST_WIDE_INT first, rtx size)
1471 /* First ensure SIZE is Pmode. */
1472 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1473 size = convert_to_mode (Pmode, size, 1);
1475 /* Next see if the front end has set up a function for us to call to
1477 if (stack_check_libfunc != 0)
1479 rtx addr = memory_address (QImode,
1480 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1482 plus_constant (size, first)));
1484 addr = convert_memory_address (ptr_mode, addr);
1485 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1489 /* Next see if we have an insn to check the stack. Use it if so. */
1490 #ifdef HAVE_check_stack
1491 else if (HAVE_check_stack)
1493 insn_operand_predicate_fn pred;
1495 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1497 plus_constant (size, first)),
1500 pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1501 if (pred && ! ((*pred) (last_addr, Pmode)))
1502 last_addr = copy_to_mode_reg (Pmode, last_addr);
1504 emit_insn (gen_check_stack (last_addr));
1508 /* If we have to generate explicit probes, see if we have a constant
1509 small number of them to generate. If so, that's the easy case. */
1510 else if (GET_CODE (size) == CONST_INT
1511 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1513 HOST_WIDE_INT offset;
1515 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1516 for values of N from 1 until it exceeds LAST. If only one
1517 probe is needed, this will not generate any code. Then probe
1519 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1520 offset < INTVAL (size);
1521 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1522 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1526 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1528 plus_constant (size, first)));
1531 /* In the variable case, do the same as above, but in a loop. We emit loop
1532 notes so that loop optimization can be done. */
1536 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1538 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1541 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1543 plus_constant (size, first)),
1545 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1546 rtx loop_lab = gen_label_rtx ();
1547 rtx test_lab = gen_label_rtx ();
1548 rtx end_lab = gen_label_rtx ();
1551 if (!REG_P (test_addr)
1552 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1553 test_addr = force_reg (Pmode, test_addr);
1555 emit_jump (test_lab);
1557 emit_label (loop_lab);
1558 emit_stack_probe (test_addr);
1560 #ifdef STACK_GROWS_DOWNWARD
1561 #define CMP_OPCODE GTU
1562 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1565 #define CMP_OPCODE LTU
1566 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1570 if (temp != test_addr)
1573 emit_label (test_lab);
1574 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1575 NULL_RTX, Pmode, 1, loop_lab);
1576 emit_jump (end_lab);
1577 emit_label (end_lab);
1579 emit_stack_probe (last_addr);
1583 /* Return an rtx representing the register or memory location
1584 in which a scalar value of data type VALTYPE
1585 was returned by a function call to function FUNC.
1586 FUNC is a FUNCTION_DECL node if the precise function is known,
1588 OUTGOING is 1 if on a machine with register windows this function
1589 should return the register in which the function will put its result
1593 hard_function_value (tree valtype, tree func ATTRIBUTE_UNUSED,
1594 int outgoing ATTRIBUTE_UNUSED)
1598 #ifdef FUNCTION_OUTGOING_VALUE
1600 val = FUNCTION_OUTGOING_VALUE (valtype, func);
1603 val = FUNCTION_VALUE (valtype, func);
1606 && GET_MODE (val) == BLKmode)
1608 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1609 enum machine_mode tmpmode;
1611 /* int_size_in_bytes can return -1. We don't need a check here
1612 since the value of bytes will be large enough that no mode
1613 will match and we will abort later in this function. */
1615 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1616 tmpmode != VOIDmode;
1617 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1619 /* Have we found a large enough mode? */
1620 if (GET_MODE_SIZE (tmpmode) >= bytes)
1624 /* No suitable mode found. */
1625 if (tmpmode == VOIDmode)
1628 PUT_MODE (val, tmpmode);
1633 /* Return an rtx representing the register or memory location
1634 in which a scalar value of mode MODE was returned by a library call. */
1637 hard_libcall_value (enum machine_mode mode)
1639 return LIBCALL_VALUE (mode);
1642 /* Look up the tree code for a given rtx code
1643 to provide the arithmetic operation for REAL_ARITHMETIC.
1644 The function returns an int because the caller may not know
1645 what `enum tree_code' means. */
1648 rtx_to_tree_code (enum rtx_code code)
1650 enum tree_code tcode;
1673 tcode = LAST_AND_UNUSED_TREE_CODE;
1676 return ((int) tcode);
1679 #include "gt-explow.h"