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, 2005 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 gcc_assert (SCALAR_INT_MODE_P (mode));
55 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
57 return c & 1 ? STORE_FLAG_VALUE : 0;
59 /* Sign-extend for the requested mode. */
61 if (width < HOST_BITS_PER_WIDE_INT)
63 HOST_WIDE_INT sign = 1;
73 /* Return an rtx for the sum of X and the integer C. */
76 plus_constant (rtx x, HOST_WIDE_INT c)
80 enum machine_mode mode;
96 return GEN_INT (INTVAL (x) + c);
100 unsigned HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
101 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
102 unsigned HOST_WIDE_INT l2 = c;
103 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
104 unsigned HOST_WIDE_INT lv;
107 add_double (l1, h1, l2, h2, &lv, &hv);
109 return immed_double_const (lv, hv, VOIDmode);
113 /* If this is a reference to the constant pool, try replacing it with
114 a reference to a new constant. If the resulting address isn't
115 valid, don't return it because we have no way to validize it. */
116 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
117 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
120 = force_const_mem (GET_MODE (x),
121 plus_constant (get_pool_constant (XEXP (x, 0)),
123 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
129 /* If adding to something entirely constant, set a flag
130 so that we can add a CONST around the result. */
141 /* The interesting case is adding the integer to a sum.
142 Look for constant term in the sum and combine
143 with C. For an integer constant term, we make a combined
144 integer. For a constant term that is not an explicit integer,
145 we cannot really combine, but group them together anyway.
147 Restart or use a recursive call in case the remaining operand is
148 something that we handle specially, such as a SYMBOL_REF.
150 We may not immediately return from the recursive call here, lest
151 all_constant gets lost. */
153 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
155 c += INTVAL (XEXP (x, 1));
157 if (GET_MODE (x) != VOIDmode)
158 c = trunc_int_for_mode (c, GET_MODE (x));
163 else if (CONSTANT_P (XEXP (x, 1)))
165 x = gen_rtx_PLUS (mode, XEXP (x, 0), plus_constant (XEXP (x, 1), c));
168 else if (find_constant_term_loc (&y))
170 /* We need to be careful since X may be shared and we can't
171 modify it in place. */
172 rtx copy = copy_rtx (x);
173 rtx *const_loc = find_constant_term_loc (©);
175 *const_loc = plus_constant (*const_loc, c);
186 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
188 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
190 else if (all_constant)
191 return gen_rtx_CONST (mode, x);
196 /* If X is a sum, return a new sum like X but lacking any constant terms.
197 Add all the removed constant terms into *CONSTPTR.
198 X itself is not altered. The result != X if and only if
199 it is not isomorphic to X. */
202 eliminate_constant_term (rtx x, rtx *constptr)
207 if (GET_CODE (x) != PLUS)
210 /* First handle constants appearing at this level explicitly. */
211 if (GET_CODE (XEXP (x, 1)) == CONST_INT
212 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
214 && GET_CODE (tem) == CONST_INT)
217 return eliminate_constant_term (XEXP (x, 0), constptr);
221 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
222 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
223 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
224 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
226 && GET_CODE (tem) == CONST_INT)
229 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
235 /* Return an rtx for the size in bytes of the value of EXP. */
242 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
243 size = TREE_OPERAND (exp, 1);
245 size = SUBSTITUTE_PLACEHOLDER_IN_EXPR (lang_hooks.expr_size (exp), exp);
247 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), 0);
250 /* Return a wide integer for the size in bytes of the value of EXP, or -1
251 if the size can vary or is larger than an integer. */
254 int_expr_size (tree exp)
258 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
259 size = TREE_OPERAND (exp, 1);
261 size = lang_hooks.expr_size (exp);
263 if (size == 0 || !host_integerp (size, 0))
266 return tree_low_cst (size, 0);
269 /* Return a copy of X in which all memory references
270 and all constants that involve symbol refs
271 have been replaced with new temporary registers.
272 Also emit code to load the memory locations and constants
273 into those registers.
275 If X contains no such constants or memory references,
276 X itself (not a copy) is returned.
278 If a constant is found in the address that is not a legitimate constant
279 in an insn, it is left alone in the hope that it might be valid in the
282 X may contain no arithmetic except addition, subtraction and multiplication.
283 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
286 break_out_memory_refs (rtx x)
289 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
290 && GET_MODE (x) != VOIDmode))
291 x = force_reg (GET_MODE (x), x);
292 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
293 || GET_CODE (x) == MULT)
295 rtx op0 = break_out_memory_refs (XEXP (x, 0));
296 rtx op1 = break_out_memory_refs (XEXP (x, 1));
298 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
299 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
305 /* Given X, a memory address in ptr_mode, convert it to an address
306 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
307 the fact that pointers are not allowed to overflow by commuting arithmetic
308 operations over conversions so that address arithmetic insns can be
312 convert_memory_address (enum machine_mode to_mode ATTRIBUTE_UNUSED,
315 #ifndef POINTERS_EXTEND_UNSIGNED
317 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
318 enum machine_mode from_mode;
322 /* If X already has the right mode, just return it. */
323 if (GET_MODE (x) == to_mode)
326 from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
328 /* Here we handle some special cases. If none of them apply, fall through
329 to the default case. */
330 switch (GET_CODE (x))
334 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
336 else if (POINTERS_EXTEND_UNSIGNED < 0)
338 else if (POINTERS_EXTEND_UNSIGNED > 0)
342 temp = simplify_unary_operation (code, to_mode, x, from_mode);
348 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
349 && GET_MODE (SUBREG_REG (x)) == to_mode)
350 return SUBREG_REG (x);
354 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
355 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
360 temp = shallow_copy_rtx (x);
361 PUT_MODE (temp, to_mode);
366 return gen_rtx_CONST (to_mode,
367 convert_memory_address (to_mode, XEXP (x, 0)));
372 /* For addition we can safely permute the conversion and addition
373 operation if one operand is a constant and converting the constant
374 does not change it. We can always safely permute them if we are
375 making the address narrower. */
376 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
377 || (GET_CODE (x) == PLUS
378 && GET_CODE (XEXP (x, 1)) == CONST_INT
379 && XEXP (x, 1) == convert_memory_address (to_mode, XEXP (x, 1))))
380 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
381 convert_memory_address (to_mode, XEXP (x, 0)),
389 return convert_modes (to_mode, from_mode,
390 x, POINTERS_EXTEND_UNSIGNED);
391 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
394 /* Return something equivalent to X but valid as a memory address
395 for something of mode MODE. When X is not itself valid, this
396 works by copying X or subexpressions of it into registers. */
399 memory_address (enum machine_mode mode, rtx x)
403 x = convert_memory_address (Pmode, x);
405 /* By passing constant addresses through registers
406 we get a chance to cse them. */
407 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
408 x = force_reg (Pmode, x);
410 /* We get better cse by rejecting indirect addressing at this stage.
411 Let the combiner create indirect addresses where appropriate.
412 For now, generate the code so that the subexpressions useful to share
413 are visible. But not if cse won't be done! */
416 if (! cse_not_expected && !REG_P (x))
417 x = break_out_memory_refs (x);
419 /* At this point, any valid address is accepted. */
420 if (memory_address_p (mode, x))
423 /* If it was valid before but breaking out memory refs invalidated it,
424 use it the old way. */
425 if (memory_address_p (mode, oldx))
428 /* Perform machine-dependent transformations on X
429 in certain cases. This is not necessary since the code
430 below can handle all possible cases, but machine-dependent
431 transformations can make better code. */
432 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
434 /* PLUS and MULT can appear in special ways
435 as the result of attempts to make an address usable for indexing.
436 Usually they are dealt with by calling force_operand, below.
437 But a sum containing constant terms is special
438 if removing them makes the sum a valid address:
439 then we generate that address in a register
440 and index off of it. We do this because it often makes
441 shorter code, and because the addresses thus generated
442 in registers often become common subexpressions. */
443 if (GET_CODE (x) == PLUS)
445 rtx constant_term = const0_rtx;
446 rtx y = eliminate_constant_term (x, &constant_term);
447 if (constant_term == const0_rtx
448 || ! memory_address_p (mode, y))
449 x = force_operand (x, NULL_RTX);
452 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
453 if (! memory_address_p (mode, y))
454 x = force_operand (x, NULL_RTX);
460 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
461 x = force_operand (x, NULL_RTX);
463 /* If we have a register that's an invalid address,
464 it must be a hard reg of the wrong class. Copy it to a pseudo. */
468 /* Last resort: copy the value to a register, since
469 the register is a valid address. */
471 x = force_reg (Pmode, x);
478 if (flag_force_addr && ! cse_not_expected && !REG_P (x)
479 /* Don't copy an addr via a reg if it is one of our stack slots. */
480 && ! (GET_CODE (x) == PLUS
481 && (XEXP (x, 0) == virtual_stack_vars_rtx
482 || XEXP (x, 0) == virtual_incoming_args_rtx)))
484 if (general_operand (x, Pmode))
485 x = force_reg (Pmode, x);
487 x = force_operand (x, NULL_RTX);
493 /* If we didn't change the address, we are done. Otherwise, mark
494 a reg as a pointer if we have REG or REG + CONST_INT. */
498 mark_reg_pointer (x, BITS_PER_UNIT);
499 else if (GET_CODE (x) == PLUS
500 && REG_P (XEXP (x, 0))
501 && GET_CODE (XEXP (x, 1)) == CONST_INT)
502 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
504 /* OLDX may have been the address on a temporary. Update the address
505 to indicate that X is now used. */
506 update_temp_slot_address (oldx, x);
511 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
514 memory_address_noforce (enum machine_mode mode, rtx x)
516 int ambient_force_addr = flag_force_addr;
520 val = memory_address (mode, x);
521 flag_force_addr = ambient_force_addr;
525 /* Convert a mem ref into one with a valid memory address.
526 Pass through anything else unchanged. */
529 validize_mem (rtx ref)
533 if (! (flag_force_addr && CONSTANT_ADDRESS_P (XEXP (ref, 0)))
534 && memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
537 /* Don't alter REF itself, since that is probably a stack slot. */
538 return replace_equiv_address (ref, XEXP (ref, 0));
541 /* Copy the value or contents of X to a new temp reg and return that reg. */
546 rtx temp = gen_reg_rtx (GET_MODE (x));
548 /* If not an operand, must be an address with PLUS and MULT so
549 do the computation. */
550 if (! general_operand (x, VOIDmode))
551 x = force_operand (x, temp);
554 emit_move_insn (temp, x);
559 /* Like copy_to_reg but always give the new register mode Pmode
560 in case X is a constant. */
563 copy_addr_to_reg (rtx x)
565 return copy_to_mode_reg (Pmode, x);
568 /* Like copy_to_reg but always give the new register mode MODE
569 in case X is a constant. */
572 copy_to_mode_reg (enum machine_mode mode, rtx x)
574 rtx temp = gen_reg_rtx (mode);
576 /* If not an operand, must be an address with PLUS and MULT so
577 do the computation. */
578 if (! general_operand (x, VOIDmode))
579 x = force_operand (x, temp);
581 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode);
583 emit_move_insn (temp, x);
587 /* Load X into a register if it is not already one.
588 Use mode MODE for the register.
589 X should be valid for mode MODE, but it may be a constant which
590 is valid for all integer modes; that's why caller must specify MODE.
592 The caller must not alter the value in the register we return,
593 since we mark it as a "constant" register. */
596 force_reg (enum machine_mode mode, rtx x)
603 if (general_operand (x, mode))
605 temp = gen_reg_rtx (mode);
606 insn = emit_move_insn (temp, x);
610 temp = force_operand (x, NULL_RTX);
612 insn = get_last_insn ();
615 rtx temp2 = gen_reg_rtx (mode);
616 insn = emit_move_insn (temp2, temp);
621 /* Let optimizers know that TEMP's value never changes
622 and that X can be substituted for it. Don't get confused
623 if INSN set something else (such as a SUBREG of TEMP). */
625 && (set = single_set (insn)) != 0
626 && SET_DEST (set) == temp
627 && ! rtx_equal_p (x, SET_SRC (set)))
628 set_unique_reg_note (insn, REG_EQUAL, x);
630 /* Let optimizers know that TEMP is a pointer, and if so, the
631 known alignment of that pointer. */
634 if (GET_CODE (x) == SYMBOL_REF)
636 align = BITS_PER_UNIT;
637 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
638 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
640 else if (GET_CODE (x) == LABEL_REF)
641 align = BITS_PER_UNIT;
642 else if (GET_CODE (x) == CONST
643 && GET_CODE (XEXP (x, 0)) == PLUS
644 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
645 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT)
647 rtx s = XEXP (XEXP (x, 0), 0);
648 rtx c = XEXP (XEXP (x, 0), 1);
652 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
653 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
655 ca = exact_log2 (INTVAL (c) & -INTVAL (c)) * BITS_PER_UNIT;
657 align = MIN (sa, ca);
661 mark_reg_pointer (temp, align);
667 /* If X is a memory ref, copy its contents to a new temp reg and return
668 that reg. Otherwise, return X. */
671 force_not_mem (rtx x)
675 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
678 temp = gen_reg_rtx (GET_MODE (x));
681 REG_POINTER (temp) = 1;
683 emit_move_insn (temp, x);
687 /* Copy X to TARGET (if it's nonzero and a reg)
688 or to a new temp reg and return that reg.
689 MODE is the mode to use for X in case it is a constant. */
692 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode)
696 if (target && REG_P (target))
699 temp = gen_reg_rtx (mode);
701 emit_move_insn (temp, x);
705 /* Return the mode to use to store a scalar of TYPE and MODE.
706 PUNSIGNEDP points to the signedness of the type and may be adjusted
707 to show what signedness to use on extension operations.
709 FOR_CALL is nonzero if this call is promoting args for a call. */
711 #if defined(PROMOTE_MODE) && !defined(PROMOTE_FUNCTION_MODE)
712 #define PROMOTE_FUNCTION_MODE PROMOTE_MODE
716 promote_mode (tree type, enum machine_mode mode, int *punsignedp,
717 int for_call ATTRIBUTE_UNUSED)
719 enum tree_code code = TREE_CODE (type);
720 int unsignedp = *punsignedp;
729 #ifdef PROMOTE_FUNCTION_MODE
730 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
731 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
736 PROMOTE_FUNCTION_MODE (mode, unsignedp, type);
741 PROMOTE_MODE (mode, unsignedp, type);
747 #ifdef POINTERS_EXTEND_UNSIGNED
751 unsignedp = POINTERS_EXTEND_UNSIGNED;
759 *punsignedp = unsignedp;
763 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
764 This pops when ADJUST is positive. ADJUST need not be constant. */
767 adjust_stack (rtx adjust)
771 if (adjust == const0_rtx)
774 /* We expect all variable sized adjustments to be multiple of
775 PREFERRED_STACK_BOUNDARY. */
776 if (GET_CODE (adjust) == CONST_INT)
777 stack_pointer_delta -= INTVAL (adjust);
779 temp = expand_binop (Pmode,
780 #ifdef STACK_GROWS_DOWNWARD
785 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
788 if (temp != stack_pointer_rtx)
789 emit_move_insn (stack_pointer_rtx, temp);
792 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
793 This pushes when ADJUST is positive. ADJUST need not be constant. */
796 anti_adjust_stack (rtx adjust)
800 if (adjust == const0_rtx)
803 /* We expect all variable sized adjustments to be multiple of
804 PREFERRED_STACK_BOUNDARY. */
805 if (GET_CODE (adjust) == CONST_INT)
806 stack_pointer_delta += INTVAL (adjust);
808 temp = expand_binop (Pmode,
809 #ifdef STACK_GROWS_DOWNWARD
814 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
817 if (temp != stack_pointer_rtx)
818 emit_move_insn (stack_pointer_rtx, temp);
821 /* Round the size of a block to be pushed up to the boundary required
822 by this machine. SIZE is the desired size, which need not be constant. */
825 round_push (rtx size)
827 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
832 if (GET_CODE (size) == CONST_INT)
834 HOST_WIDE_INT new = (INTVAL (size) + align - 1) / align * align;
836 if (INTVAL (size) != new)
837 size = GEN_INT (new);
841 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
842 but we know it can't. So add ourselves and then do
844 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
845 NULL_RTX, 1, OPTAB_LIB_WIDEN);
846 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
848 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
854 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
855 to a previously-created save area. If no save area has been allocated,
856 this function will allocate one. If a save area is specified, it
857 must be of the proper mode.
859 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
860 are emitted at the current position. */
863 emit_stack_save (enum save_level save_level, rtx *psave, rtx after)
866 /* The default is that we use a move insn and save in a Pmode object. */
867 rtx (*fcn) (rtx, rtx) = gen_move_insn;
868 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
870 /* See if this machine has anything special to do for this kind of save. */
873 #ifdef HAVE_save_stack_block
875 if (HAVE_save_stack_block)
876 fcn = gen_save_stack_block;
879 #ifdef HAVE_save_stack_function
881 if (HAVE_save_stack_function)
882 fcn = gen_save_stack_function;
885 #ifdef HAVE_save_stack_nonlocal
887 if (HAVE_save_stack_nonlocal)
888 fcn = gen_save_stack_nonlocal;
895 /* If there is no save area and we have to allocate one, do so. Otherwise
896 verify the save area is the proper mode. */
900 if (mode != VOIDmode)
902 if (save_level == SAVE_NONLOCAL)
903 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
905 *psave = sa = gen_reg_rtx (mode);
914 do_pending_stack_adjust ();
915 /* We must validize inside the sequence, to ensure that any instructions
916 created by the validize call also get moved to the right place. */
918 sa = validize_mem (sa);
919 emit_insn (fcn (sa, stack_pointer_rtx));
922 emit_insn_after (seq, after);
926 do_pending_stack_adjust ();
928 sa = validize_mem (sa);
929 emit_insn (fcn (sa, stack_pointer_rtx));
933 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
934 area made by emit_stack_save. If it is zero, we have nothing to do.
936 Put any emitted insns after insn AFTER, if nonzero, otherwise at
940 emit_stack_restore (enum save_level save_level, rtx sa, rtx after)
942 /* The default is that we use a move insn. */
943 rtx (*fcn) (rtx, rtx) = gen_move_insn;
945 /* See if this machine has anything special to do for this kind of save. */
948 #ifdef HAVE_restore_stack_block
950 if (HAVE_restore_stack_block)
951 fcn = gen_restore_stack_block;
954 #ifdef HAVE_restore_stack_function
956 if (HAVE_restore_stack_function)
957 fcn = gen_restore_stack_function;
960 #ifdef HAVE_restore_stack_nonlocal
962 if (HAVE_restore_stack_nonlocal)
963 fcn = gen_restore_stack_nonlocal;
972 sa = validize_mem (sa);
973 /* These clobbers prevent the scheduler from moving
974 references to variable arrays below the code
975 that deletes (pops) the arrays. */
976 emit_insn (gen_rtx_CLOBBER (VOIDmode,
977 gen_rtx_MEM (BLKmode,
978 gen_rtx_SCRATCH (VOIDmode))));
979 emit_insn (gen_rtx_CLOBBER (VOIDmode,
980 gen_rtx_MEM (BLKmode, stack_pointer_rtx)));
983 discard_pending_stack_adjust ();
990 emit_insn (fcn (stack_pointer_rtx, sa));
993 emit_insn_after (seq, after);
996 emit_insn (fcn (stack_pointer_rtx, sa));
999 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1000 function. This function should be called whenever we allocate or
1001 deallocate dynamic stack space. */
1004 update_nonlocal_goto_save_area (void)
1009 /* The nonlocal_goto_save_area object is an array of N pointers. The
1010 first one is used for the frame pointer save; the rest are sized by
1011 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1012 of the stack save area slots. */
1013 t_save = build4 (ARRAY_REF, ptr_type_node, cfun->nonlocal_goto_save_area,
1014 integer_one_node, NULL_TREE, NULL_TREE);
1015 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1017 emit_stack_save (SAVE_NONLOCAL, &r_save, NULL_RTX);
1020 /* Return an rtx representing the address of an area of memory dynamically
1021 pushed on the stack. This region of memory is always aligned to
1022 a multiple of BIGGEST_ALIGNMENT.
1024 Any required stack pointer alignment is preserved.
1026 SIZE is an rtx representing the size of the area.
1027 TARGET is a place in which the address can be placed.
1029 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1032 allocate_dynamic_stack_space (rtx size, rtx target, int known_align)
1034 /* If we're asking for zero bytes, it doesn't matter what we point
1035 to since we can't dereference it. But return a reasonable
1037 if (size == const0_rtx)
1038 return virtual_stack_dynamic_rtx;
1040 /* Otherwise, show we're calling alloca or equivalent. */
1041 current_function_calls_alloca = 1;
1043 /* Ensure the size is in the proper mode. */
1044 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1045 size = convert_to_mode (Pmode, size, 1);
1047 /* We can't attempt to minimize alignment necessary, because we don't
1048 know the final value of preferred_stack_boundary yet while executing
1050 cfun->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1052 /* We will need to ensure that the address we return is aligned to
1053 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1054 always know its final value at this point in the compilation (it
1055 might depend on the size of the outgoing parameter lists, for
1056 example), so we must align the value to be returned in that case.
1057 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1058 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1059 We must also do an alignment operation on the returned value if
1060 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1062 If we have to align, we must leave space in SIZE for the hole
1063 that might result from the alignment operation. */
1065 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1066 #define MUST_ALIGN 1
1068 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1073 = force_operand (plus_constant (size,
1074 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1077 #ifdef SETJMP_VIA_SAVE_AREA
1078 /* If setjmp restores regs from a save area in the stack frame,
1079 avoid clobbering the reg save area. Note that the offset of
1080 virtual_incoming_args_rtx includes the preallocated stack args space.
1081 It would be no problem to clobber that, but it's on the wrong side
1082 of the old save area.
1084 What used to happen is that, since we did not know for sure
1085 whether setjmp() was invoked until after RTL generation, we
1086 would use reg notes to store the "optimized" size and fix things
1087 up later. These days we know this information before we ever
1088 start building RTL so the reg notes are unnecessary. */
1089 if (!current_function_calls_setjmp)
1091 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1093 /* ??? Code below assumes that the save area needs maximal
1094 alignment. This constraint may be too strong. */
1095 gcc_assert (PREFERRED_STACK_BOUNDARY == BIGGEST_ALIGNMENT);
1097 if (GET_CODE (size) == CONST_INT)
1099 HOST_WIDE_INT new = INTVAL (size) / align * align;
1101 if (INTVAL (size) != new)
1102 size = GEN_INT (new);
1106 /* Since we know overflow is not possible, we avoid using
1107 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1108 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1109 GEN_INT (align), NULL_RTX, 1);
1110 size = expand_mult (Pmode, size,
1111 GEN_INT (align), NULL_RTX, 1);
1117 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1118 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1120 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1121 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1123 #endif /* SETJMP_VIA_SAVE_AREA */
1125 /* Round the size to a multiple of the required stack alignment.
1126 Since the stack if presumed to be rounded before this allocation,
1127 this will maintain the required alignment.
1129 If the stack grows downward, we could save an insn by subtracting
1130 SIZE from the stack pointer and then aligning the stack pointer.
1131 The problem with this is that the stack pointer may be unaligned
1132 between the execution of the subtraction and alignment insns and
1133 some machines do not allow this. Even on those that do, some
1134 signal handlers malfunction if a signal should occur between those
1135 insns. Since this is an extremely rare event, we have no reliable
1136 way of knowing which systems have this problem. So we avoid even
1137 momentarily mis-aligning the stack. */
1139 /* If we added a variable amount to SIZE,
1140 we can no longer assume it is aligned. */
1141 #if !defined (SETJMP_VIA_SAVE_AREA)
1142 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1144 size = round_push (size);
1146 do_pending_stack_adjust ();
1148 /* We ought to be called always on the toplevel and stack ought to be aligned
1150 gcc_assert (!(stack_pointer_delta
1151 % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)));
1153 /* If needed, check that we have the required amount of stack. Take into
1154 account what has already been checked. */
1155 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1156 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1158 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1159 if (target == 0 || !REG_P (target)
1160 || REGNO (target) < FIRST_PSEUDO_REGISTER
1161 || GET_MODE (target) != Pmode)
1162 target = gen_reg_rtx (Pmode);
1164 mark_reg_pointer (target, known_align);
1166 /* Perform the required allocation from the stack. Some systems do
1167 this differently than simply incrementing/decrementing from the
1168 stack pointer, such as acquiring the space by calling malloc(). */
1169 #ifdef HAVE_allocate_stack
1170 if (HAVE_allocate_stack)
1172 enum machine_mode mode = STACK_SIZE_MODE;
1173 insn_operand_predicate_fn pred;
1175 /* We don't have to check against the predicate for operand 0 since
1176 TARGET is known to be a pseudo of the proper mode, which must
1177 be valid for the operand. For operand 1, convert to the
1178 proper mode and validate. */
1179 if (mode == VOIDmode)
1180 mode = insn_data[(int) CODE_FOR_allocate_stack].operand[1].mode;
1182 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1183 if (pred && ! ((*pred) (size, mode)))
1184 size = copy_to_mode_reg (mode, convert_to_mode (mode, size, 1));
1186 emit_insn (gen_allocate_stack (target, size));
1191 #ifndef STACK_GROWS_DOWNWARD
1192 emit_move_insn (target, virtual_stack_dynamic_rtx);
1195 /* Check stack bounds if necessary. */
1196 if (current_function_limit_stack)
1199 rtx space_available = gen_label_rtx ();
1200 #ifdef STACK_GROWS_DOWNWARD
1201 available = expand_binop (Pmode, sub_optab,
1202 stack_pointer_rtx, stack_limit_rtx,
1203 NULL_RTX, 1, OPTAB_WIDEN);
1205 available = expand_binop (Pmode, sub_optab,
1206 stack_limit_rtx, stack_pointer_rtx,
1207 NULL_RTX, 1, OPTAB_WIDEN);
1209 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1213 emit_insn (gen_trap ());
1216 error ("stack limits not supported on this target");
1218 emit_label (space_available);
1221 anti_adjust_stack (size);
1223 #ifdef STACK_GROWS_DOWNWARD
1224 emit_move_insn (target, virtual_stack_dynamic_rtx);
1230 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1231 but we know it can't. So add ourselves and then do
1233 target = expand_binop (Pmode, add_optab, target,
1234 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1235 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1236 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1237 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1239 target = expand_mult (Pmode, target,
1240 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1244 /* Record the new stack level for nonlocal gotos. */
1245 if (cfun->nonlocal_goto_save_area != 0)
1246 update_nonlocal_goto_save_area ();
1251 /* A front end may want to override GCC's stack checking by providing a
1252 run-time routine to call to check the stack, so provide a mechanism for
1253 calling that routine. */
1255 static GTY(()) rtx stack_check_libfunc;
1258 set_stack_check_libfunc (rtx libfunc)
1260 stack_check_libfunc = libfunc;
1263 /* Emit one stack probe at ADDRESS, an address within the stack. */
1266 emit_stack_probe (rtx address)
1268 rtx memref = gen_rtx_MEM (word_mode, address);
1270 MEM_VOLATILE_P (memref) = 1;
1272 if (STACK_CHECK_PROBE_LOAD)
1273 emit_move_insn (gen_reg_rtx (word_mode), memref);
1275 emit_move_insn (memref, const0_rtx);
1278 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1279 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1280 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1281 subtract from the stack. If SIZE is constant, this is done
1282 with a fixed number of probes. Otherwise, we must make a loop. */
1284 #ifdef STACK_GROWS_DOWNWARD
1285 #define STACK_GROW_OP MINUS
1287 #define STACK_GROW_OP PLUS
1291 probe_stack_range (HOST_WIDE_INT first, rtx size)
1293 /* First ensure SIZE is Pmode. */
1294 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1295 size = convert_to_mode (Pmode, size, 1);
1297 /* Next see if the front end has set up a function for us to call to
1299 if (stack_check_libfunc != 0)
1301 rtx addr = memory_address (QImode,
1302 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1304 plus_constant (size, first)));
1306 addr = convert_memory_address (ptr_mode, addr);
1307 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1311 /* Next see if we have an insn to check the stack. Use it if so. */
1312 #ifdef HAVE_check_stack
1313 else if (HAVE_check_stack)
1315 insn_operand_predicate_fn pred;
1317 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1319 plus_constant (size, first)),
1322 pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1323 if (pred && ! ((*pred) (last_addr, Pmode)))
1324 last_addr = copy_to_mode_reg (Pmode, last_addr);
1326 emit_insn (gen_check_stack (last_addr));
1330 /* If we have to generate explicit probes, see if we have a constant
1331 small number of them to generate. If so, that's the easy case. */
1332 else if (GET_CODE (size) == CONST_INT
1333 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1335 HOST_WIDE_INT offset;
1337 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1338 for values of N from 1 until it exceeds LAST. If only one
1339 probe is needed, this will not generate any code. Then probe
1341 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1342 offset < INTVAL (size);
1343 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1344 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1348 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1350 plus_constant (size, first)));
1353 /* In the variable case, do the same as above, but in a loop. We emit loop
1354 notes so that loop optimization can be done. */
1358 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1360 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1363 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1365 plus_constant (size, first)),
1367 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1368 rtx loop_lab = gen_label_rtx ();
1369 rtx test_lab = gen_label_rtx ();
1370 rtx end_lab = gen_label_rtx ();
1373 if (!REG_P (test_addr)
1374 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1375 test_addr = force_reg (Pmode, test_addr);
1377 emit_jump (test_lab);
1379 emit_label (loop_lab);
1380 emit_stack_probe (test_addr);
1382 #ifdef STACK_GROWS_DOWNWARD
1383 #define CMP_OPCODE GTU
1384 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1387 #define CMP_OPCODE LTU
1388 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1392 gcc_assert (temp == test_addr);
1394 emit_label (test_lab);
1395 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1396 NULL_RTX, Pmode, 1, loop_lab);
1397 emit_jump (end_lab);
1398 emit_label (end_lab);
1400 emit_stack_probe (last_addr);
1404 /* Return an rtx representing the register or memory location
1405 in which a scalar value of data type VALTYPE
1406 was returned by a function call to function FUNC.
1407 FUNC is a FUNCTION_DECL node if the precise function is known,
1409 OUTGOING is 1 if on a machine with register windows this function
1410 should return the register in which the function will put its result
1414 hard_function_value (tree valtype, tree func ATTRIBUTE_UNUSED,
1415 int outgoing ATTRIBUTE_UNUSED)
1419 #ifdef FUNCTION_OUTGOING_VALUE
1421 val = FUNCTION_OUTGOING_VALUE (valtype, func);
1424 val = FUNCTION_VALUE (valtype, func);
1427 && GET_MODE (val) == BLKmode)
1429 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1430 enum machine_mode tmpmode;
1432 /* int_size_in_bytes can return -1. We don't need a check here
1433 since the value of bytes will then be large enough that no
1434 mode will match anyway. */
1436 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1437 tmpmode != VOIDmode;
1438 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1440 /* Have we found a large enough mode? */
1441 if (GET_MODE_SIZE (tmpmode) >= bytes)
1445 /* No suitable mode found. */
1446 gcc_assert (tmpmode != VOIDmode);
1448 PUT_MODE (val, tmpmode);
1453 /* Return an rtx representing the register or memory location
1454 in which a scalar value of mode MODE was returned by a library call. */
1457 hard_libcall_value (enum machine_mode mode)
1459 return LIBCALL_VALUE (mode);
1462 /* Look up the tree code for a given rtx code
1463 to provide the arithmetic operation for REAL_ARITHMETIC.
1464 The function returns an int because the caller may not know
1465 what `enum tree_code' means. */
1468 rtx_to_tree_code (enum rtx_code code)
1470 enum tree_code tcode;
1493 tcode = LAST_AND_UNUSED_TREE_CODE;
1496 return ((int) tcode);
1499 #include "gt-explow.h"