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 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
461 /* If it was valid before but breaking out memory refs invalidated it,
462 use it the old way. */
463 if (memory_address_p (mode, oldx))
466 /* Perform machine-dependent transformations on X
467 in certain cases. This is not necessary since the code
468 below can handle all possible cases, but machine-dependent
469 transformations can make better code. */
470 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
472 /* PLUS and MULT can appear in special ways
473 as the result of attempts to make an address usable for indexing.
474 Usually they are dealt with by calling force_operand, below.
475 But a sum containing constant terms is special
476 if removing them makes the sum a valid address:
477 then we generate that address in a register
478 and index off of it. We do this because it often makes
479 shorter code, and because the addresses thus generated
480 in registers often become common subexpressions. */
481 if (GET_CODE (x) == PLUS)
483 rtx constant_term = const0_rtx;
484 rtx y = eliminate_constant_term (x, &constant_term);
485 if (constant_term == const0_rtx
486 || ! memory_address_p (mode, y))
487 x = force_operand (x, NULL_RTX);
490 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
491 if (! memory_address_p (mode, y))
492 x = force_operand (x, NULL_RTX);
498 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
499 x = force_operand (x, NULL_RTX);
501 /* If we have a register that's an invalid address,
502 it must be a hard reg of the wrong class. Copy it to a pseudo. */
506 /* Last resort: copy the value to a register, since
507 the register is a valid address. */
509 x = force_reg (Pmode, x);
516 if (flag_force_addr && ! cse_not_expected && !REG_P (x)
517 /* Don't copy an addr via a reg if it is one of our stack slots. */
518 && ! (GET_CODE (x) == PLUS
519 && (XEXP (x, 0) == virtual_stack_vars_rtx
520 || XEXP (x, 0) == virtual_incoming_args_rtx)))
522 if (general_operand (x, Pmode))
523 x = force_reg (Pmode, x);
525 x = force_operand (x, NULL_RTX);
531 /* If we didn't change the address, we are done. Otherwise, mark
532 a reg as a pointer if we have REG or REG + CONST_INT. */
536 mark_reg_pointer (x, BITS_PER_UNIT);
537 else if (GET_CODE (x) == PLUS
538 && REG_P (XEXP (x, 0))
539 && GET_CODE (XEXP (x, 1)) == CONST_INT)
540 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
542 /* OLDX may have been the address on a temporary. Update the address
543 to indicate that X is now used. */
544 update_temp_slot_address (oldx, x);
549 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
552 memory_address_noforce (enum machine_mode mode, rtx x)
554 int ambient_force_addr = flag_force_addr;
558 val = memory_address (mode, x);
559 flag_force_addr = ambient_force_addr;
563 /* Convert a mem ref into one with a valid memory address.
564 Pass through anything else unchanged. */
567 validize_mem (rtx ref)
571 if (! (flag_force_addr && CONSTANT_ADDRESS_P (XEXP (ref, 0)))
572 && memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
575 /* Don't alter REF itself, since that is probably a stack slot. */
576 return replace_equiv_address (ref, XEXP (ref, 0));
579 /* Given REF, either a MEM or a REG, and T, either the type of X or
580 the expression corresponding to REF, set RTX_UNCHANGING_P if
584 maybe_set_unchanging (rtx ref, tree t)
586 /* We can set RTX_UNCHANGING_P from TREE_READONLY for decls whose
587 initialization is only executed once, or whose initializer always
588 has the same value. Currently we simplify this to PARM_DECLs in the
589 first case, and decls with TREE_CONSTANT initializers in the second.
591 We cannot do this for non-static aggregates, because of the double
592 writes that can be generated by store_constructor, depending on the
593 contents of the initializer. Yes, this does eliminate a good fraction
594 of the number of uses of RTX_UNCHANGING_P for a language like Ada.
595 It also eliminates a good quantity of bugs. Let this be incentive to
596 eliminate RTX_UNCHANGING_P entirely in favor of a more reliable
597 solution, perhaps based on alias sets. */
599 if ((TREE_READONLY (t) && DECL_P (t)
600 && (TREE_STATIC (t) || ! AGGREGATE_TYPE_P (TREE_TYPE (t)))
601 && (TREE_CODE (t) == PARM_DECL
602 || (DECL_INITIAL (t) && TREE_CONSTANT (DECL_INITIAL (t)))))
603 || TREE_CODE_CLASS (TREE_CODE (t)) == 'c')
604 RTX_UNCHANGING_P (ref) = 1;
607 /* Return a modified copy of X with its memory address copied
608 into a temporary register to protect it from side effects.
609 If X is not a MEM, it is returned unchanged (and not copied).
610 Perhaps even if it is a MEM, if there is no need to change it. */
616 || ! rtx_unstable_p (XEXP (x, 0)))
620 replace_equiv_address (x, force_reg (Pmode, copy_all_regs (XEXP (x, 0))));
623 /* Copy the value or contents of X to a new temp reg and return that reg. */
628 rtx temp = gen_reg_rtx (GET_MODE (x));
630 /* If not an operand, must be an address with PLUS and MULT so
631 do the computation. */
632 if (! general_operand (x, VOIDmode))
633 x = force_operand (x, temp);
636 emit_move_insn (temp, x);
641 /* Like copy_to_reg but always give the new register mode Pmode
642 in case X is a constant. */
645 copy_addr_to_reg (rtx x)
647 return copy_to_mode_reg (Pmode, x);
650 /* Like copy_to_reg but always give the new register mode MODE
651 in case X is a constant. */
654 copy_to_mode_reg (enum machine_mode mode, rtx x)
656 rtx temp = gen_reg_rtx (mode);
658 /* If not an operand, must be an address with PLUS and MULT so
659 do the computation. */
660 if (! general_operand (x, VOIDmode))
661 x = force_operand (x, temp);
663 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
666 emit_move_insn (temp, x);
670 /* Load X into a register if it is not already one.
671 Use mode MODE for the register.
672 X should be valid for mode MODE, but it may be a constant which
673 is valid for all integer modes; that's why caller must specify MODE.
675 The caller must not alter the value in the register we return,
676 since we mark it as a "constant" register. */
679 force_reg (enum machine_mode mode, rtx x)
686 if (general_operand (x, mode))
688 temp = gen_reg_rtx (mode);
689 insn = emit_move_insn (temp, x);
693 temp = force_operand (x, NULL_RTX);
695 insn = get_last_insn ();
698 rtx temp2 = gen_reg_rtx (mode);
699 insn = emit_move_insn (temp2, temp);
704 /* Let optimizers know that TEMP's value never changes
705 and that X can be substituted for it. Don't get confused
706 if INSN set something else (such as a SUBREG of TEMP). */
708 && (set = single_set (insn)) != 0
709 && SET_DEST (set) == temp
710 && ! rtx_equal_p (x, SET_SRC (set)))
711 set_unique_reg_note (insn, REG_EQUAL, x);
713 /* Let optimizers know that TEMP is a pointer, and if so, the
714 known alignment of that pointer. */
717 if (GET_CODE (x) == SYMBOL_REF)
719 align = BITS_PER_UNIT;
720 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
721 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
723 else if (GET_CODE (x) == LABEL_REF)
724 align = BITS_PER_UNIT;
725 else if (GET_CODE (x) == CONST
726 && GET_CODE (XEXP (x, 0)) == PLUS
727 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
728 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT)
730 rtx s = XEXP (XEXP (x, 0), 0);
731 rtx c = XEXP (XEXP (x, 0), 1);
735 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
736 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
738 ca = exact_log2 (INTVAL (c) & -INTVAL (c)) * BITS_PER_UNIT;
740 align = MIN (sa, ca);
744 mark_reg_pointer (temp, align);
750 /* If X is a memory ref, copy its contents to a new temp reg and return
751 that reg. Otherwise, return X. */
754 force_not_mem (rtx x)
758 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
761 temp = gen_reg_rtx (GET_MODE (x));
764 REG_POINTER (temp) = 1;
766 emit_move_insn (temp, x);
770 /* Copy X to TARGET (if it's nonzero and a reg)
771 or to a new temp reg and return that reg.
772 MODE is the mode to use for X in case it is a constant. */
775 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode)
779 if (target && REG_P (target))
782 temp = gen_reg_rtx (mode);
784 emit_move_insn (temp, x);
788 /* Return the mode to use to store a scalar of TYPE and MODE.
789 PUNSIGNEDP points to the signedness of the type and may be adjusted
790 to show what signedness to use on extension operations.
792 FOR_CALL is nonzero if this call is promoting args for a call. */
794 #if defined(PROMOTE_MODE) && !defined(PROMOTE_FUNCTION_MODE)
795 #define PROMOTE_FUNCTION_MODE PROMOTE_MODE
799 promote_mode (tree type, enum machine_mode mode, int *punsignedp,
800 int for_call ATTRIBUTE_UNUSED)
802 enum tree_code code = TREE_CODE (type);
803 int unsignedp = *punsignedp;
812 #ifdef PROMOTE_FUNCTION_MODE
813 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
814 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
819 PROMOTE_FUNCTION_MODE (mode, unsignedp, type);
824 PROMOTE_MODE (mode, unsignedp, type);
830 #ifdef POINTERS_EXTEND_UNSIGNED
834 unsignedp = POINTERS_EXTEND_UNSIGNED;
842 *punsignedp = unsignedp;
846 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
847 This pops when ADJUST is positive. ADJUST need not be constant. */
850 adjust_stack (rtx adjust)
854 if (adjust == const0_rtx)
857 /* We expect all variable sized adjustments to be multiple of
858 PREFERRED_STACK_BOUNDARY. */
859 if (GET_CODE (adjust) == CONST_INT)
860 stack_pointer_delta -= INTVAL (adjust);
862 temp = expand_binop (Pmode,
863 #ifdef STACK_GROWS_DOWNWARD
868 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
871 if (temp != stack_pointer_rtx)
872 emit_move_insn (stack_pointer_rtx, temp);
875 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
876 This pushes when ADJUST is positive. ADJUST need not be constant. */
879 anti_adjust_stack (rtx adjust)
883 if (adjust == const0_rtx)
886 /* We expect all variable sized adjustments to be multiple of
887 PREFERRED_STACK_BOUNDARY. */
888 if (GET_CODE (adjust) == CONST_INT)
889 stack_pointer_delta += INTVAL (adjust);
891 temp = expand_binop (Pmode,
892 #ifdef STACK_GROWS_DOWNWARD
897 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
900 if (temp != stack_pointer_rtx)
901 emit_move_insn (stack_pointer_rtx, temp);
904 /* Round the size of a block to be pushed up to the boundary required
905 by this machine. SIZE is the desired size, which need not be constant. */
908 round_push (rtx size)
910 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
915 if (GET_CODE (size) == CONST_INT)
917 HOST_WIDE_INT new = (INTVAL (size) + align - 1) / align * align;
919 if (INTVAL (size) != new)
920 size = GEN_INT (new);
924 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
925 but we know it can't. So add ourselves and then do
927 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
928 NULL_RTX, 1, OPTAB_LIB_WIDEN);
929 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
931 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
937 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
938 to a previously-created save area. If no save area has been allocated,
939 this function will allocate one. If a save area is specified, it
940 must be of the proper mode.
942 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
943 are emitted at the current position. */
946 emit_stack_save (enum save_level save_level, rtx *psave, rtx after)
949 /* The default is that we use a move insn and save in a Pmode object. */
950 rtx (*fcn) (rtx, rtx) = gen_move_insn;
951 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
953 /* See if this machine has anything special to do for this kind of save. */
956 #ifdef HAVE_save_stack_block
958 if (HAVE_save_stack_block)
959 fcn = gen_save_stack_block;
962 #ifdef HAVE_save_stack_function
964 if (HAVE_save_stack_function)
965 fcn = gen_save_stack_function;
968 #ifdef HAVE_save_stack_nonlocal
970 if (HAVE_save_stack_nonlocal)
971 fcn = gen_save_stack_nonlocal;
978 /* If there is no save area and we have to allocate one, do so. Otherwise
979 verify the save area is the proper mode. */
983 if (mode != VOIDmode)
985 if (save_level == SAVE_NONLOCAL)
986 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
988 *psave = sa = gen_reg_rtx (mode);
997 /* We must validize inside the sequence, to ensure that any instructions
998 created by the validize call also get moved to the right place. */
1000 sa = validize_mem (sa);
1001 emit_insn (fcn (sa, stack_pointer_rtx));
1004 emit_insn_after (seq, after);
1009 sa = validize_mem (sa);
1010 emit_insn (fcn (sa, stack_pointer_rtx));
1014 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1015 area made by emit_stack_save. If it is zero, we have nothing to do.
1017 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1018 current position. */
1021 emit_stack_restore (enum save_level save_level, rtx sa, rtx after)
1023 /* The default is that we use a move insn. */
1024 rtx (*fcn) (rtx, rtx) = gen_move_insn;
1026 /* See if this machine has anything special to do for this kind of save. */
1029 #ifdef HAVE_restore_stack_block
1031 if (HAVE_restore_stack_block)
1032 fcn = gen_restore_stack_block;
1035 #ifdef HAVE_restore_stack_function
1037 if (HAVE_restore_stack_function)
1038 fcn = gen_restore_stack_function;
1041 #ifdef HAVE_restore_stack_nonlocal
1043 if (HAVE_restore_stack_nonlocal)
1044 fcn = gen_restore_stack_nonlocal;
1053 sa = validize_mem (sa);
1054 /* These clobbers prevent the scheduler from moving
1055 references to variable arrays below the code
1056 that deletes (pops) the arrays. */
1057 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1058 gen_rtx_MEM (BLKmode,
1059 gen_rtx_SCRATCH (VOIDmode))));
1060 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1061 gen_rtx_MEM (BLKmode, stack_pointer_rtx)));
1069 emit_insn (fcn (stack_pointer_rtx, sa));
1072 emit_insn_after (seq, after);
1075 emit_insn (fcn (stack_pointer_rtx, sa));
1078 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1079 function. This function should be called whenever we allocate or
1080 deallocate dynamic stack space. */
1083 update_nonlocal_goto_save_area (void)
1088 /* The nonlocal_goto_save_area object is an array of N pointers. The
1089 first one is used for the frame pointer save; the rest are sized by
1090 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1091 of the stack save area slots. */
1092 t_save = build (ARRAY_REF, ptr_type_node, cfun->nonlocal_goto_save_area,
1093 integer_one_node, NULL_TREE, NULL_TREE);
1094 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1096 emit_stack_save (SAVE_NONLOCAL, &r_save, NULL_RTX);
1099 #ifdef SETJMP_VIA_SAVE_AREA
1100 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1101 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1102 platforms, the dynamic stack space used can corrupt the original
1103 frame, thus causing a crash if a longjmp unwinds to it. */
1106 optimize_save_area_alloca (void)
1110 for (insn = get_insns (); insn; insn = NEXT_INSN(insn))
1114 if (!NONJUMP_INSN_P (insn))
1117 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1119 if (REG_NOTE_KIND (note) != REG_SAVE_AREA)
1122 if (!current_function_calls_setjmp)
1124 rtx pat = PATTERN (insn);
1126 /* If we do not see the note in a pattern matching
1127 these precise characteristics, we did something
1128 entirely wrong in allocate_dynamic_stack_space.
1130 Note, one way this could happen is if SETJMP_VIA_SAVE_AREA
1131 was defined on a machine where stacks grow towards higher
1134 Right now only supported port with stack that grow upward
1135 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1136 if (GET_CODE (pat) != SET
1137 || SET_DEST (pat) != stack_pointer_rtx
1138 || GET_CODE (SET_SRC (pat)) != MINUS
1139 || XEXP (SET_SRC (pat), 0) != stack_pointer_rtx)
1142 /* This will now be transformed into a (set REG REG)
1143 so we can just blow away all the other notes. */
1144 XEXP (SET_SRC (pat), 1) = XEXP (note, 0);
1145 REG_NOTES (insn) = NULL_RTX;
1149 /* setjmp was called, we must remove the REG_SAVE_AREA
1150 note so that later passes do not get confused by its
1152 if (note == REG_NOTES (insn))
1154 REG_NOTES (insn) = XEXP (note, 1);
1160 for (srch = REG_NOTES (insn); srch; srch = XEXP (srch, 1))
1161 if (XEXP (srch, 1) == note)
1164 if (srch == NULL_RTX)
1167 XEXP (srch, 1) = XEXP (note, 1);
1170 /* Once we've seen the note of interest, we need not look at
1171 the rest of them. */
1176 #endif /* SETJMP_VIA_SAVE_AREA */
1178 /* Return an rtx representing the address of an area of memory dynamically
1179 pushed on the stack. This region of memory is always aligned to
1180 a multiple of BIGGEST_ALIGNMENT.
1182 Any required stack pointer alignment is preserved.
1184 SIZE is an rtx representing the size of the area.
1185 TARGET is a place in which the address can be placed.
1187 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1190 allocate_dynamic_stack_space (rtx size, rtx target, int known_align)
1192 #ifdef SETJMP_VIA_SAVE_AREA
1193 rtx setjmpless_size = NULL_RTX;
1196 /* If we're asking for zero bytes, it doesn't matter what we point
1197 to since we can't dereference it. But return a reasonable
1199 if (size == const0_rtx)
1200 return virtual_stack_dynamic_rtx;
1202 /* Otherwise, show we're calling alloca or equivalent. */
1203 current_function_calls_alloca = 1;
1205 /* Ensure the size is in the proper mode. */
1206 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1207 size = convert_to_mode (Pmode, size, 1);
1209 /* We can't attempt to minimize alignment necessary, because we don't
1210 know the final value of preferred_stack_boundary yet while executing
1212 cfun->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1214 /* We will need to ensure that the address we return is aligned to
1215 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1216 always know its final value at this point in the compilation (it
1217 might depend on the size of the outgoing parameter lists, for
1218 example), so we must align the value to be returned in that case.
1219 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1220 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1221 We must also do an alignment operation on the returned value if
1222 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1224 If we have to align, we must leave space in SIZE for the hole
1225 that might result from the alignment operation. */
1227 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1228 #define MUST_ALIGN 1
1230 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1235 = force_operand (plus_constant (size,
1236 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1239 #ifdef SETJMP_VIA_SAVE_AREA
1240 /* If setjmp restores regs from a save area in the stack frame,
1241 avoid clobbering the reg save area. Note that the offset of
1242 virtual_incoming_args_rtx includes the preallocated stack args space.
1243 It would be no problem to clobber that, but it's on the wrong side
1244 of the old save area. */
1247 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1248 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1250 if (!current_function_calls_setjmp)
1252 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1254 /* See optimize_save_area_alloca to understand what is being
1257 /* ??? Code below assumes that the save area needs maximal
1258 alignment. This constraint may be too strong. */
1259 if (PREFERRED_STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1262 if (GET_CODE (size) == CONST_INT)
1264 HOST_WIDE_INT new = INTVAL (size) / align * align;
1266 if (INTVAL (size) != new)
1267 setjmpless_size = GEN_INT (new);
1269 setjmpless_size = size;
1273 /* Since we know overflow is not possible, we avoid using
1274 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1275 setjmpless_size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1276 GEN_INT (align), NULL_RTX, 1);
1277 setjmpless_size = expand_mult (Pmode, setjmpless_size,
1278 GEN_INT (align), NULL_RTX, 1);
1280 /* Our optimization works based upon being able to perform a simple
1281 transformation of this RTL into a (set REG REG) so make sure things
1282 did in fact end up in a REG. */
1283 if (!register_operand (setjmpless_size, Pmode))
1284 setjmpless_size = force_reg (Pmode, setjmpless_size);
1287 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1288 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1290 #endif /* SETJMP_VIA_SAVE_AREA */
1292 /* Round the size to a multiple of the required stack alignment.
1293 Since the stack if presumed to be rounded before this allocation,
1294 this will maintain the required alignment.
1296 If the stack grows downward, we could save an insn by subtracting
1297 SIZE from the stack pointer and then aligning the stack pointer.
1298 The problem with this is that the stack pointer may be unaligned
1299 between the execution of the subtraction and alignment insns and
1300 some machines do not allow this. Even on those that do, some
1301 signal handlers malfunction if a signal should occur between those
1302 insns. Since this is an extremely rare event, we have no reliable
1303 way of knowing which systems have this problem. So we avoid even
1304 momentarily mis-aligning the stack. */
1306 /* If we added a variable amount to SIZE,
1307 we can no longer assume it is aligned. */
1308 #if !defined (SETJMP_VIA_SAVE_AREA)
1309 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1311 size = round_push (size);
1313 do_pending_stack_adjust ();
1315 /* We ought to be called always on the toplevel and stack ought to be aligned
1317 if (stack_pointer_delta % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT))
1320 /* If needed, check that we have the required amount of stack. Take into
1321 account what has already been checked. */
1322 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1323 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1325 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1326 if (target == 0 || !REG_P (target)
1327 || REGNO (target) < FIRST_PSEUDO_REGISTER
1328 || GET_MODE (target) != Pmode)
1329 target = gen_reg_rtx (Pmode);
1331 mark_reg_pointer (target, known_align);
1333 /* Perform the required allocation from the stack. Some systems do
1334 this differently than simply incrementing/decrementing from the
1335 stack pointer, such as acquiring the space by calling malloc(). */
1336 #ifdef HAVE_allocate_stack
1337 if (HAVE_allocate_stack)
1339 enum machine_mode mode = STACK_SIZE_MODE;
1340 insn_operand_predicate_fn pred;
1342 /* We don't have to check against the predicate for operand 0 since
1343 TARGET is known to be a pseudo of the proper mode, which must
1344 be valid for the operand. For operand 1, convert to the
1345 proper mode and validate. */
1346 if (mode == VOIDmode)
1347 mode = insn_data[(int) CODE_FOR_allocate_stack].operand[1].mode;
1349 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1350 if (pred && ! ((*pred) (size, mode)))
1351 size = copy_to_mode_reg (mode, convert_to_mode (mode, size, 1));
1353 emit_insn (gen_allocate_stack (target, size));
1358 #ifndef STACK_GROWS_DOWNWARD
1359 emit_move_insn (target, virtual_stack_dynamic_rtx);
1362 /* Check stack bounds if necessary. */
1363 if (current_function_limit_stack)
1366 rtx space_available = gen_label_rtx ();
1367 #ifdef STACK_GROWS_DOWNWARD
1368 available = expand_binop (Pmode, sub_optab,
1369 stack_pointer_rtx, stack_limit_rtx,
1370 NULL_RTX, 1, OPTAB_WIDEN);
1372 available = expand_binop (Pmode, sub_optab,
1373 stack_limit_rtx, stack_pointer_rtx,
1374 NULL_RTX, 1, OPTAB_WIDEN);
1376 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1380 emit_insn (gen_trap ());
1383 error ("stack limits not supported on this target");
1385 emit_label (space_available);
1388 anti_adjust_stack (size);
1389 #ifdef SETJMP_VIA_SAVE_AREA
1390 if (setjmpless_size != NULL_RTX)
1392 rtx note_target = get_last_insn ();
1394 REG_NOTES (note_target)
1395 = gen_rtx_EXPR_LIST (REG_SAVE_AREA, setjmpless_size,
1396 REG_NOTES (note_target));
1398 #endif /* SETJMP_VIA_SAVE_AREA */
1400 #ifdef STACK_GROWS_DOWNWARD
1401 emit_move_insn (target, virtual_stack_dynamic_rtx);
1407 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1408 but we know it can't. So add ourselves and then do
1410 target = expand_binop (Pmode, add_optab, target,
1411 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1412 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1413 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1414 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1416 target = expand_mult (Pmode, target,
1417 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1421 /* Record the new stack level for nonlocal gotos. */
1422 if (cfun->nonlocal_goto_save_area != 0)
1423 update_nonlocal_goto_save_area ();
1428 /* A front end may want to override GCC's stack checking by providing a
1429 run-time routine to call to check the stack, so provide a mechanism for
1430 calling that routine. */
1432 static GTY(()) rtx stack_check_libfunc;
1435 set_stack_check_libfunc (rtx libfunc)
1437 stack_check_libfunc = libfunc;
1440 /* Emit one stack probe at ADDRESS, an address within the stack. */
1443 emit_stack_probe (rtx address)
1445 rtx memref = gen_rtx_MEM (word_mode, address);
1447 MEM_VOLATILE_P (memref) = 1;
1449 if (STACK_CHECK_PROBE_LOAD)
1450 emit_move_insn (gen_reg_rtx (word_mode), memref);
1452 emit_move_insn (memref, const0_rtx);
1455 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1456 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1457 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1458 subtract from the stack. If SIZE is constant, this is done
1459 with a fixed number of probes. Otherwise, we must make a loop. */
1461 #ifdef STACK_GROWS_DOWNWARD
1462 #define STACK_GROW_OP MINUS
1464 #define STACK_GROW_OP PLUS
1468 probe_stack_range (HOST_WIDE_INT first, rtx size)
1470 /* First ensure SIZE is Pmode. */
1471 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1472 size = convert_to_mode (Pmode, size, 1);
1474 /* Next see if the front end has set up a function for us to call to
1476 if (stack_check_libfunc != 0)
1478 rtx addr = memory_address (QImode,
1479 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1481 plus_constant (size, first)));
1483 addr = convert_memory_address (ptr_mode, addr);
1484 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1488 /* Next see if we have an insn to check the stack. Use it if so. */
1489 #ifdef HAVE_check_stack
1490 else if (HAVE_check_stack)
1492 insn_operand_predicate_fn pred;
1494 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1496 plus_constant (size, first)),
1499 pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1500 if (pred && ! ((*pred) (last_addr, Pmode)))
1501 last_addr = copy_to_mode_reg (Pmode, last_addr);
1503 emit_insn (gen_check_stack (last_addr));
1507 /* If we have to generate explicit probes, see if we have a constant
1508 small number of them to generate. If so, that's the easy case. */
1509 else if (GET_CODE (size) == CONST_INT
1510 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1512 HOST_WIDE_INT offset;
1514 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1515 for values of N from 1 until it exceeds LAST. If only one
1516 probe is needed, this will not generate any code. Then probe
1518 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1519 offset < INTVAL (size);
1520 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1521 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1525 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1527 plus_constant (size, first)));
1530 /* In the variable case, do the same as above, but in a loop. We emit loop
1531 notes so that loop optimization can be done. */
1535 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1537 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1540 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1542 plus_constant (size, first)),
1544 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1545 rtx loop_lab = gen_label_rtx ();
1546 rtx test_lab = gen_label_rtx ();
1547 rtx end_lab = gen_label_rtx ();
1550 if (!REG_P (test_addr)
1551 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1552 test_addr = force_reg (Pmode, test_addr);
1554 emit_jump (test_lab);
1556 emit_label (loop_lab);
1557 emit_stack_probe (test_addr);
1559 #ifdef STACK_GROWS_DOWNWARD
1560 #define CMP_OPCODE GTU
1561 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1564 #define CMP_OPCODE LTU
1565 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1569 if (temp != test_addr)
1572 emit_label (test_lab);
1573 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1574 NULL_RTX, Pmode, 1, loop_lab);
1575 emit_jump (end_lab);
1576 emit_label (end_lab);
1578 emit_stack_probe (last_addr);
1582 /* Return an rtx representing the register or memory location
1583 in which a scalar value of data type VALTYPE
1584 was returned by a function call to function FUNC.
1585 FUNC is a FUNCTION_DECL node if the precise function is known,
1587 OUTGOING is 1 if on a machine with register windows this function
1588 should return the register in which the function will put its result
1592 hard_function_value (tree valtype, tree func ATTRIBUTE_UNUSED,
1593 int outgoing ATTRIBUTE_UNUSED)
1597 #ifdef FUNCTION_OUTGOING_VALUE
1599 val = FUNCTION_OUTGOING_VALUE (valtype, func);
1602 val = FUNCTION_VALUE (valtype, func);
1605 && GET_MODE (val) == BLKmode)
1607 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1608 enum machine_mode tmpmode;
1610 /* int_size_in_bytes can return -1. We don't need a check here
1611 since the value of bytes will be large enough that no mode
1612 will match and we will abort later in this function. */
1614 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1615 tmpmode != VOIDmode;
1616 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1618 /* Have we found a large enough mode? */
1619 if (GET_MODE_SIZE (tmpmode) >= bytes)
1623 /* No suitable mode found. */
1624 if (tmpmode == VOIDmode)
1627 PUT_MODE (val, tmpmode);
1632 /* Return an rtx representing the register or memory location
1633 in which a scalar value of mode MODE was returned by a library call. */
1636 hard_libcall_value (enum machine_mode mode)
1638 return LIBCALL_VALUE (mode);
1641 /* Look up the tree code for a given rtx code
1642 to provide the arithmetic operation for REAL_ARITHMETIC.
1643 The function returns an int because the caller may not know
1644 what `enum tree_code' means. */
1647 rtx_to_tree_code (enum rtx_code code)
1649 enum tree_code tcode;
1672 tcode = LAST_AND_UNUSED_TREE_CODE;
1675 return ((int) tcode);
1678 #include "gt-explow.h"