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, 2006, 2007, 2008
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
25 #include "coretypes.h"
27 #include "diagnostic-core.h"
38 #include "hard-reg-set.h"
39 #include "insn-config.h"
42 #include "langhooks.h"
46 static rtx break_out_memory_refs (rtx);
49 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
52 trunc_int_for_mode (HOST_WIDE_INT c, enum machine_mode mode)
54 int width = GET_MODE_BITSIZE (mode);
56 /* You want to truncate to a _what_? */
57 gcc_assert (SCALAR_INT_MODE_P (mode));
59 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
61 return c & 1 ? STORE_FLAG_VALUE : 0;
63 /* Sign-extend for the requested mode. */
65 if (width < HOST_BITS_PER_WIDE_INT)
67 HOST_WIDE_INT sign = 1;
77 /* Return an rtx for the sum of X and the integer C. */
80 plus_constant (rtx x, HOST_WIDE_INT c)
84 enum machine_mode mode;
100 return GEN_INT (INTVAL (x) + c);
104 unsigned HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
105 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
106 unsigned HOST_WIDE_INT l2 = c;
107 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
108 unsigned HOST_WIDE_INT lv;
111 add_double (l1, h1, l2, h2, &lv, &hv);
113 return immed_double_const (lv, hv, VOIDmode);
117 /* If this is a reference to the constant pool, try replacing it with
118 a reference to a new constant. If the resulting address isn't
119 valid, don't return it because we have no way to validize it. */
120 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
121 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
124 = force_const_mem (GET_MODE (x),
125 plus_constant (get_pool_constant (XEXP (x, 0)),
127 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
133 /* If adding to something entirely constant, set a flag
134 so that we can add a CONST around the result. */
145 /* The interesting case is adding the integer to a sum.
146 Look for constant term in the sum and combine
147 with C. For an integer constant term, we make a combined
148 integer. For a constant term that is not an explicit integer,
149 we cannot really combine, but group them together anyway.
151 Restart or use a recursive call in case the remaining operand is
152 something that we handle specially, such as a SYMBOL_REF.
154 We may not immediately return from the recursive call here, lest
155 all_constant gets lost. */
157 if (CONST_INT_P (XEXP (x, 1)))
159 c += INTVAL (XEXP (x, 1));
161 if (GET_MODE (x) != VOIDmode)
162 c = trunc_int_for_mode (c, GET_MODE (x));
167 else if (CONSTANT_P (XEXP (x, 1)))
169 x = gen_rtx_PLUS (mode, XEXP (x, 0), plus_constant (XEXP (x, 1), c));
172 else if (find_constant_term_loc (&y))
174 /* We need to be careful since X may be shared and we can't
175 modify it in place. */
176 rtx copy = copy_rtx (x);
177 rtx *const_loc = find_constant_term_loc (©);
179 *const_loc = plus_constant (*const_loc, c);
190 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
192 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
194 else if (all_constant)
195 return gen_rtx_CONST (mode, x);
200 /* If X is a sum, return a new sum like X but lacking any constant terms.
201 Add all the removed constant terms into *CONSTPTR.
202 X itself is not altered. The result != X if and only if
203 it is not isomorphic to X. */
206 eliminate_constant_term (rtx x, rtx *constptr)
211 if (GET_CODE (x) != PLUS)
214 /* First handle constants appearing at this level explicitly. */
215 if (CONST_INT_P (XEXP (x, 1))
216 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
218 && CONST_INT_P (tem))
221 return eliminate_constant_term (XEXP (x, 0), constptr);
225 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
226 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
227 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
228 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
230 && CONST_INT_P (tem))
233 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
239 /* Return an rtx for the size in bytes of the value of EXP. */
246 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
247 size = TREE_OPERAND (exp, 1);
250 size = tree_expr_size (exp);
252 gcc_assert (size == SUBSTITUTE_PLACEHOLDER_IN_EXPR (size, exp));
255 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), EXPAND_NORMAL);
258 /* Return a wide integer for the size in bytes of the value of EXP, or -1
259 if the size can vary or is larger than an integer. */
262 int_expr_size (tree exp)
266 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
267 size = TREE_OPERAND (exp, 1);
270 size = tree_expr_size (exp);
274 if (size == 0 || !host_integerp (size, 0))
277 return tree_low_cst (size, 0);
280 /* Return a copy of X in which all memory references
281 and all constants that involve symbol refs
282 have been replaced with new temporary registers.
283 Also emit code to load the memory locations and constants
284 into those registers.
286 If X contains no such constants or memory references,
287 X itself (not a copy) is returned.
289 If a constant is found in the address that is not a legitimate constant
290 in an insn, it is left alone in the hope that it might be valid in the
293 X may contain no arithmetic except addition, subtraction and multiplication.
294 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
297 break_out_memory_refs (rtx x)
300 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
301 && GET_MODE (x) != VOIDmode))
302 x = force_reg (GET_MODE (x), x);
303 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
304 || GET_CODE (x) == MULT)
306 rtx op0 = break_out_memory_refs (XEXP (x, 0));
307 rtx op1 = break_out_memory_refs (XEXP (x, 1));
309 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
310 x = simplify_gen_binary (GET_CODE (x), GET_MODE (x), op0, op1);
316 /* Given X, a memory address in address space AS' pointer mode, convert it to
317 an address in the address space's address mode, or vice versa (TO_MODE says
318 which way). We take advantage of the fact that pointers are not allowed to
319 overflow by commuting arithmetic operations over conversions so that address
320 arithmetic insns can be used. */
323 convert_memory_address_addr_space (enum machine_mode to_mode ATTRIBUTE_UNUSED,
324 rtx x, addr_space_t as ATTRIBUTE_UNUSED)
326 #ifndef POINTERS_EXTEND_UNSIGNED
327 gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode);
329 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
330 enum machine_mode pointer_mode, address_mode, from_mode;
334 /* If X already has the right mode, just return it. */
335 if (GET_MODE (x) == to_mode)
338 pointer_mode = targetm.addr_space.pointer_mode (as);
339 address_mode = targetm.addr_space.address_mode (as);
340 from_mode = to_mode == pointer_mode ? address_mode : pointer_mode;
342 /* Here we handle some special cases. If none of them apply, fall through
343 to the default case. */
344 switch (GET_CODE (x))
348 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
350 else if (POINTERS_EXTEND_UNSIGNED < 0)
352 else if (POINTERS_EXTEND_UNSIGNED > 0)
356 temp = simplify_unary_operation (code, to_mode, x, from_mode);
362 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
363 && GET_MODE (SUBREG_REG (x)) == to_mode)
364 return SUBREG_REG (x);
368 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
369 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
374 temp = shallow_copy_rtx (x);
375 PUT_MODE (temp, to_mode);
380 return gen_rtx_CONST (to_mode,
381 convert_memory_address_addr_space
382 (to_mode, XEXP (x, 0), as));
387 /* For addition we can safely permute the conversion and addition
388 operation if one operand is a constant and converting the constant
389 does not change it or if one operand is a constant and we are
390 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
391 We can always safely permute them if we are making the address
393 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
394 || (GET_CODE (x) == PLUS
395 && CONST_INT_P (XEXP (x, 1))
396 && (XEXP (x, 1) == convert_memory_address_addr_space
397 (to_mode, XEXP (x, 1), as)
398 || POINTERS_EXTEND_UNSIGNED < 0)))
399 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
400 convert_memory_address_addr_space
401 (to_mode, XEXP (x, 0), as),
409 return convert_modes (to_mode, from_mode,
410 x, POINTERS_EXTEND_UNSIGNED);
411 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
414 /* Return something equivalent to X but valid as a memory address for something
415 of mode MODE in the named address space AS. When X is not itself valid,
416 this works by copying X or subexpressions of it into registers. */
419 memory_address_addr_space (enum machine_mode mode, rtx x, addr_space_t as)
422 enum machine_mode address_mode = targetm.addr_space.address_mode (as);
424 x = convert_memory_address_addr_space (address_mode, x, as);
426 /* By passing constant addresses through registers
427 we get a chance to cse them. */
428 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
429 x = force_reg (address_mode, x);
431 /* We get better cse by rejecting indirect addressing at this stage.
432 Let the combiner create indirect addresses where appropriate.
433 For now, generate the code so that the subexpressions useful to share
434 are visible. But not if cse won't be done! */
437 if (! cse_not_expected && !REG_P (x))
438 x = break_out_memory_refs (x);
440 /* At this point, any valid address is accepted. */
441 if (memory_address_addr_space_p (mode, x, as))
444 /* If it was valid before but breaking out memory refs invalidated it,
445 use it the old way. */
446 if (memory_address_addr_space_p (mode, oldx, as))
452 /* Perform machine-dependent transformations on X
453 in certain cases. This is not necessary since the code
454 below can handle all possible cases, but machine-dependent
455 transformations can make better code. */
458 x = targetm.addr_space.legitimize_address (x, oldx, mode, as);
459 if (orig_x != x && memory_address_addr_space_p (mode, x, as))
463 /* PLUS and MULT can appear in special ways
464 as the result of attempts to make an address usable for indexing.
465 Usually they are dealt with by calling force_operand, below.
466 But a sum containing constant terms is special
467 if removing them makes the sum a valid address:
468 then we generate that address in a register
469 and index off of it. We do this because it often makes
470 shorter code, and because the addresses thus generated
471 in registers often become common subexpressions. */
472 if (GET_CODE (x) == PLUS)
474 rtx constant_term = const0_rtx;
475 rtx y = eliminate_constant_term (x, &constant_term);
476 if (constant_term == const0_rtx
477 || ! memory_address_addr_space_p (mode, y, as))
478 x = force_operand (x, NULL_RTX);
481 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
482 if (! memory_address_addr_space_p (mode, y, as))
483 x = force_operand (x, NULL_RTX);
489 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
490 x = force_operand (x, NULL_RTX);
492 /* If we have a register that's an invalid address,
493 it must be a hard reg of the wrong class. Copy it to a pseudo. */
497 /* Last resort: copy the value to a register, since
498 the register is a valid address. */
500 x = force_reg (address_mode, x);
505 gcc_assert (memory_address_addr_space_p (mode, x, as));
506 /* If we didn't change the address, we are done. Otherwise, mark
507 a reg as a pointer if we have REG or REG + CONST_INT. */
511 mark_reg_pointer (x, BITS_PER_UNIT);
512 else if (GET_CODE (x) == PLUS
513 && REG_P (XEXP (x, 0))
514 && CONST_INT_P (XEXP (x, 1)))
515 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
517 /* OLDX may have been the address on a temporary. Update the address
518 to indicate that X is now used. */
519 update_temp_slot_address (oldx, x);
524 /* Convert a mem ref into one with a valid memory address.
525 Pass through anything else unchanged. */
528 validize_mem (rtx ref)
532 ref = use_anchored_address (ref);
533 if (memory_address_addr_space_p (GET_MODE (ref), XEXP (ref, 0),
534 MEM_ADDR_SPACE (ref)))
537 /* Don't alter REF itself, since that is probably a stack slot. */
538 return replace_equiv_address (ref, XEXP (ref, 0));
541 /* If X is a memory reference to a member of an object block, try rewriting
542 it to use an anchor instead. Return the new memory reference on success
543 and the old one on failure. */
546 use_anchored_address (rtx x)
549 HOST_WIDE_INT offset;
551 if (!flag_section_anchors)
557 /* Split the address into a base and offset. */
560 if (GET_CODE (base) == CONST
561 && GET_CODE (XEXP (base, 0)) == PLUS
562 && CONST_INT_P (XEXP (XEXP (base, 0), 1)))
564 offset += INTVAL (XEXP (XEXP (base, 0), 1));
565 base = XEXP (XEXP (base, 0), 0);
568 /* Check whether BASE is suitable for anchors. */
569 if (GET_CODE (base) != SYMBOL_REF
570 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base)
571 || SYMBOL_REF_ANCHOR_P (base)
572 || SYMBOL_REF_BLOCK (base) == NULL
573 || !targetm.use_anchors_for_symbol_p (base))
576 /* Decide where BASE is going to be. */
577 place_block_symbol (base);
579 /* Get the anchor we need to use. */
580 offset += SYMBOL_REF_BLOCK_OFFSET (base);
581 base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset,
582 SYMBOL_REF_TLS_MODEL (base));
584 /* Work out the offset from the anchor. */
585 offset -= SYMBOL_REF_BLOCK_OFFSET (base);
587 /* If we're going to run a CSE pass, force the anchor into a register.
588 We will then be able to reuse registers for several accesses, if the
589 target costs say that that's worthwhile. */
590 if (!cse_not_expected)
591 base = force_reg (GET_MODE (base), base);
593 return replace_equiv_address (x, plus_constant (base, offset));
596 /* Copy the value or contents of X to a new temp reg and return that reg. */
601 rtx temp = gen_reg_rtx (GET_MODE (x));
603 /* If not an operand, must be an address with PLUS and MULT so
604 do the computation. */
605 if (! general_operand (x, VOIDmode))
606 x = force_operand (x, temp);
609 emit_move_insn (temp, x);
614 /* Like copy_to_reg but always give the new register mode Pmode
615 in case X is a constant. */
618 copy_addr_to_reg (rtx x)
620 return copy_to_mode_reg (Pmode, x);
623 /* Like copy_to_reg but always give the new register mode MODE
624 in case X is a constant. */
627 copy_to_mode_reg (enum machine_mode mode, rtx x)
629 rtx temp = gen_reg_rtx (mode);
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);
636 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode);
638 emit_move_insn (temp, x);
642 /* Load X into a register if it is not already one.
643 Use mode MODE for the register.
644 X should be valid for mode MODE, but it may be a constant which
645 is valid for all integer modes; that's why caller must specify MODE.
647 The caller must not alter the value in the register we return,
648 since we mark it as a "constant" register. */
651 force_reg (enum machine_mode mode, rtx x)
658 if (general_operand (x, mode))
660 temp = gen_reg_rtx (mode);
661 insn = emit_move_insn (temp, x);
665 temp = force_operand (x, NULL_RTX);
667 insn = get_last_insn ();
670 rtx temp2 = gen_reg_rtx (mode);
671 insn = emit_move_insn (temp2, temp);
676 /* Let optimizers know that TEMP's value never changes
677 and that X can be substituted for it. Don't get confused
678 if INSN set something else (such as a SUBREG of TEMP). */
680 && (set = single_set (insn)) != 0
681 && SET_DEST (set) == temp
682 && ! rtx_equal_p (x, SET_SRC (set)))
683 set_unique_reg_note (insn, REG_EQUAL, x);
685 /* Let optimizers know that TEMP is a pointer, and if so, the
686 known alignment of that pointer. */
689 if (GET_CODE (x) == SYMBOL_REF)
691 align = BITS_PER_UNIT;
692 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
693 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
695 else if (GET_CODE (x) == LABEL_REF)
696 align = BITS_PER_UNIT;
697 else if (GET_CODE (x) == CONST
698 && GET_CODE (XEXP (x, 0)) == PLUS
699 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
700 && CONST_INT_P (XEXP (XEXP (x, 0), 1)))
702 rtx s = XEXP (XEXP (x, 0), 0);
703 rtx c = XEXP (XEXP (x, 0), 1);
707 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
708 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
714 ca = ctz_hwi (INTVAL (c)) * BITS_PER_UNIT;
715 align = MIN (sa, ca);
719 if (align || (MEM_P (x) && MEM_POINTER (x)))
720 mark_reg_pointer (temp, align);
726 /* If X is a memory ref, copy its contents to a new temp reg and return
727 that reg. Otherwise, return X. */
730 force_not_mem (rtx x)
734 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
737 temp = gen_reg_rtx (GET_MODE (x));
740 REG_POINTER (temp) = 1;
742 emit_move_insn (temp, x);
746 /* Copy X to TARGET (if it's nonzero and a reg)
747 or to a new temp reg and return that reg.
748 MODE is the mode to use for X in case it is a constant. */
751 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode)
755 if (target && REG_P (target))
758 temp = gen_reg_rtx (mode);
760 emit_move_insn (temp, x);
764 /* Return the mode to use to pass or return a scalar of TYPE and MODE.
765 PUNSIGNEDP points to the signedness of the type and may be adjusted
766 to show what signedness to use on extension operations.
768 FOR_RETURN is nonzero if the caller is promoting the return value
769 of FNDECL, else it is for promoting args. */
772 promote_function_mode (const_tree type, enum machine_mode mode, int *punsignedp,
773 const_tree funtype, int for_return)
775 switch (TREE_CODE (type))
777 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
778 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
779 case POINTER_TYPE: case REFERENCE_TYPE:
780 return targetm.calls.promote_function_mode (type, mode, punsignedp, funtype,
787 /* Return the mode to use to store a scalar of TYPE and MODE.
788 PUNSIGNEDP points to the signedness of the type and may be adjusted
789 to show what signedness to use on extension operations. */
792 promote_mode (const_tree type ATTRIBUTE_UNUSED, enum machine_mode mode,
793 int *punsignedp ATTRIBUTE_UNUSED)
795 /* FIXME: this is the same logic that was there until GCC 4.4, but we
796 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
797 is not defined. The affected targets are M32C, S390, SPARC. */
799 const enum tree_code code = TREE_CODE (type);
800 int unsignedp = *punsignedp;
804 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
805 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
806 PROMOTE_MODE (mode, unsignedp, type);
807 *punsignedp = unsignedp;
811 #ifdef POINTERS_EXTEND_UNSIGNED
814 *punsignedp = POINTERS_EXTEND_UNSIGNED;
815 return targetm.addr_space.address_mode
816 (TYPE_ADDR_SPACE (TREE_TYPE (type)));
829 /* Use one of promote_mode or promote_function_mode to find the promoted
830 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
831 of DECL after promotion. */
834 promote_decl_mode (const_tree decl, int *punsignedp)
836 tree type = TREE_TYPE (decl);
837 int unsignedp = TYPE_UNSIGNED (type);
838 enum machine_mode mode = DECL_MODE (decl);
839 enum machine_mode pmode;
841 if (TREE_CODE (decl) == RESULT_DECL
842 || TREE_CODE (decl) == PARM_DECL)
843 pmode = promote_function_mode (type, mode, &unsignedp,
844 TREE_TYPE (current_function_decl), 2);
846 pmode = promote_mode (type, mode, &unsignedp);
849 *punsignedp = unsignedp;
854 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
855 This pops when ADJUST is positive. ADJUST need not be constant. */
858 adjust_stack (rtx adjust)
862 if (adjust == const0_rtx)
865 /* We expect all variable sized adjustments to be multiple of
866 PREFERRED_STACK_BOUNDARY. */
867 if (CONST_INT_P (adjust))
868 stack_pointer_delta -= INTVAL (adjust);
870 temp = expand_binop (Pmode,
871 #ifdef STACK_GROWS_DOWNWARD
876 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
879 if (temp != stack_pointer_rtx)
880 emit_move_insn (stack_pointer_rtx, temp);
883 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
884 This pushes when ADJUST is positive. ADJUST need not be constant. */
887 anti_adjust_stack (rtx adjust)
891 if (adjust == const0_rtx)
894 /* We expect all variable sized adjustments to be multiple of
895 PREFERRED_STACK_BOUNDARY. */
896 if (CONST_INT_P (adjust))
897 stack_pointer_delta += INTVAL (adjust);
899 temp = expand_binop (Pmode,
900 #ifdef STACK_GROWS_DOWNWARD
905 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
908 if (temp != stack_pointer_rtx)
909 emit_move_insn (stack_pointer_rtx, temp);
912 /* Round the size of a block to be pushed up to the boundary required
913 by this machine. SIZE is the desired size, which need not be constant. */
916 round_push (rtx size)
918 rtx align_rtx, alignm1_rtx;
920 if (!SUPPORTS_STACK_ALIGNMENT
921 || crtl->preferred_stack_boundary == MAX_SUPPORTED_STACK_ALIGNMENT)
923 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
928 if (CONST_INT_P (size))
930 HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align;
932 if (INTVAL (size) != new_size)
933 size = GEN_INT (new_size);
937 align_rtx = GEN_INT (align);
938 alignm1_rtx = GEN_INT (align - 1);
942 /* If crtl->preferred_stack_boundary might still grow, use
943 virtual_preferred_stack_boundary_rtx instead. This will be
944 substituted by the right value in vregs pass and optimized
946 align_rtx = virtual_preferred_stack_boundary_rtx;
947 alignm1_rtx = force_operand (plus_constant (align_rtx, -1), NULL_RTX);
950 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
951 but we know it can't. So add ourselves and then do
953 size = expand_binop (Pmode, add_optab, size, alignm1_rtx,
954 NULL_RTX, 1, OPTAB_LIB_WIDEN);
955 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, align_rtx,
957 size = expand_mult (Pmode, size, align_rtx, NULL_RTX, 1);
962 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
963 to a previously-created save area. If no save area has been allocated,
964 this function will allocate one. If a save area is specified, it
965 must be of the proper mode.
967 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
968 are emitted at the current position. */
971 emit_stack_save (enum save_level save_level, rtx *psave, rtx after)
974 /* The default is that we use a move insn and save in a Pmode object. */
975 rtx (*fcn) (rtx, rtx) = gen_move_insn;
976 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
978 /* See if this machine has anything special to do for this kind of save. */
981 #ifdef HAVE_save_stack_block
983 if (HAVE_save_stack_block)
984 fcn = gen_save_stack_block;
987 #ifdef HAVE_save_stack_function
989 if (HAVE_save_stack_function)
990 fcn = gen_save_stack_function;
993 #ifdef HAVE_save_stack_nonlocal
995 if (HAVE_save_stack_nonlocal)
996 fcn = gen_save_stack_nonlocal;
1003 /* If there is no save area and we have to allocate one, do so. Otherwise
1004 verify the save area is the proper mode. */
1008 if (mode != VOIDmode)
1010 if (save_level == SAVE_NONLOCAL)
1011 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
1013 *psave = sa = gen_reg_rtx (mode);
1022 do_pending_stack_adjust ();
1023 /* We must validize inside the sequence, to ensure that any instructions
1024 created by the validize call also get moved to the right place. */
1026 sa = validize_mem (sa);
1027 emit_insn (fcn (sa, stack_pointer_rtx));
1030 emit_insn_after (seq, after);
1034 do_pending_stack_adjust ();
1036 sa = validize_mem (sa);
1037 emit_insn (fcn (sa, stack_pointer_rtx));
1041 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1042 area made by emit_stack_save. If it is zero, we have nothing to do.
1044 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1045 current position. */
1048 emit_stack_restore (enum save_level save_level, rtx sa, rtx after)
1050 /* The default is that we use a move insn. */
1051 rtx (*fcn) (rtx, rtx) = gen_move_insn;
1053 /* See if this machine has anything special to do for this kind of save. */
1056 #ifdef HAVE_restore_stack_block
1058 if (HAVE_restore_stack_block)
1059 fcn = gen_restore_stack_block;
1062 #ifdef HAVE_restore_stack_function
1064 if (HAVE_restore_stack_function)
1065 fcn = gen_restore_stack_function;
1068 #ifdef HAVE_restore_stack_nonlocal
1070 if (HAVE_restore_stack_nonlocal)
1071 fcn = gen_restore_stack_nonlocal;
1080 sa = validize_mem (sa);
1081 /* These clobbers prevent the scheduler from moving
1082 references to variable arrays below the code
1083 that deletes (pops) the arrays. */
1084 emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
1085 emit_clobber (gen_rtx_MEM (BLKmode, stack_pointer_rtx));
1088 discard_pending_stack_adjust ();
1095 emit_insn (fcn (stack_pointer_rtx, sa));
1098 emit_insn_after (seq, after);
1101 emit_insn (fcn (stack_pointer_rtx, sa));
1104 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1105 function. This function should be called whenever we allocate or
1106 deallocate dynamic stack space. */
1109 update_nonlocal_goto_save_area (void)
1114 /* The nonlocal_goto_save_area object is an array of N pointers. The
1115 first one is used for the frame pointer save; the rest are sized by
1116 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1117 of the stack save area slots. */
1118 t_save = build4 (ARRAY_REF, ptr_type_node, cfun->nonlocal_goto_save_area,
1119 integer_one_node, NULL_TREE, NULL_TREE);
1120 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1122 emit_stack_save (SAVE_NONLOCAL, &r_save, NULL_RTX);
1125 /* Return an rtx representing the address of an area of memory dynamically
1126 pushed on the stack. This region of memory is always aligned to
1127 a multiple of BIGGEST_ALIGNMENT.
1129 Any required stack pointer alignment is preserved.
1131 SIZE is an rtx representing the size of the area.
1132 TARGET is a place in which the address can be placed.
1134 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has.
1136 If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
1137 stack space allocated by the generated code cannot be added with itself
1138 in the course of the execution of the function. It is always safe to
1139 pass FALSE here and the following criterion is sufficient in order to
1140 pass TRUE: every path in the CFG that starts at the allocation point and
1141 loops to it executes the associated deallocation code. */
1144 allocate_dynamic_stack_space (rtx size, rtx target, int known_align,
1145 bool cannot_accumulate)
1147 HOST_WIDE_INT stack_usage_size = -1;
1148 bool known_align_valid = true;
1150 /* If we're asking for zero bytes, it doesn't matter what we point
1151 to since we can't dereference it. But return a reasonable
1153 if (size == const0_rtx)
1154 return virtual_stack_dynamic_rtx;
1156 /* Otherwise, show we're calling alloca or equivalent. */
1157 cfun->calls_alloca = 1;
1159 /* If stack usage info is requested, look into the size we are passed.
1160 We need to do so this early to avoid the obfuscation that may be
1161 introduced later by the various alignment operations. */
1162 if (flag_stack_usage)
1164 if (CONST_INT_P (size))
1165 stack_usage_size = INTVAL (size);
1166 else if (REG_P (size))
1168 /* Look into the last emitted insn and see if we can deduce
1169 something for the register. */
1170 rtx insn, set, note;
1171 insn = get_last_insn ();
1172 if ((set = single_set (insn)) && rtx_equal_p (SET_DEST (set), size))
1174 if (CONST_INT_P (SET_SRC (set)))
1175 stack_usage_size = INTVAL (SET_SRC (set));
1176 else if ((note = find_reg_equal_equiv_note (insn))
1177 && CONST_INT_P (XEXP (note, 0)))
1178 stack_usage_size = INTVAL (XEXP (note, 0));
1182 /* If the size is not constant, we can't say anything. */
1183 if (stack_usage_size == -1)
1185 current_function_has_unbounded_dynamic_stack_size = 1;
1186 stack_usage_size = 0;
1190 /* Ensure the size is in the proper mode. */
1191 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1192 size = convert_to_mode (Pmode, size, 1);
1194 /* We can't attempt to minimize alignment necessary, because we don't
1195 know the final value of preferred_stack_boundary yet while executing
1197 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
1198 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1200 /* We will need to ensure that the address we return is aligned to
1201 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1202 always know its final value at this point in the compilation (it
1203 might depend on the size of the outgoing parameter lists, for
1204 example), so we must align the value to be returned in that case.
1205 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1206 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1207 We must also do an alignment operation on the returned value if
1208 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1210 If we have to align, we must leave space in SIZE for the hole
1211 that might result from the alignment operation. */
1213 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1214 #define MUST_ALIGN 1
1216 #define MUST_ALIGN (crtl->preferred_stack_boundary < BIGGEST_ALIGNMENT)
1222 = force_operand (plus_constant (size,
1223 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1226 if (flag_stack_usage)
1227 stack_usage_size += BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1;
1229 known_align_valid = false;
1232 #ifdef SETJMP_VIA_SAVE_AREA
1233 /* If setjmp restores regs from a save area in the stack frame,
1234 avoid clobbering the reg save area. Note that the offset of
1235 virtual_incoming_args_rtx includes the preallocated stack args space.
1236 It would be no problem to clobber that, but it's on the wrong side
1237 of the old save area.
1239 What used to happen is that, since we did not know for sure
1240 whether setjmp() was invoked until after RTL generation, we
1241 would use reg notes to store the "optimized" size and fix things
1242 up later. These days we know this information before we ever
1243 start building RTL so the reg notes are unnecessary. */
1244 if (cfun->calls_setjmp)
1247 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1248 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1250 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1251 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1253 /* The above dynamic offset cannot be computed statically at this
1254 point, but it will be possible to do so after RTL expansion is
1255 done. Record how many times we will need to add it. */
1256 if (flag_stack_usage)
1257 current_function_dynamic_alloc_count++;
1259 known_align_valid = false;
1261 #endif /* SETJMP_VIA_SAVE_AREA */
1263 /* Round the size to a multiple of the required stack alignment.
1264 Since the stack if presumed to be rounded before this allocation,
1265 this will maintain the required alignment.
1267 If the stack grows downward, we could save an insn by subtracting
1268 SIZE from the stack pointer and then aligning the stack pointer.
1269 The problem with this is that the stack pointer may be unaligned
1270 between the execution of the subtraction and alignment insns and
1271 some machines do not allow this. Even on those that do, some
1272 signal handlers malfunction if a signal should occur between those
1273 insns. Since this is an extremely rare event, we have no reliable
1274 way of knowing which systems have this problem. So we avoid even
1275 momentarily mis-aligning the stack. */
1276 if (!known_align_valid || known_align % MAX_SUPPORTED_STACK_ALIGNMENT != 0)
1278 size = round_push (size);
1280 if (flag_stack_usage)
1282 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
1283 stack_usage_size = (stack_usage_size + align - 1) / align * align;
1287 /* The size is supposed to be fully adjusted at this point so record it
1288 if stack usage info is requested. */
1289 if (flag_stack_usage)
1291 current_function_dynamic_stack_size += stack_usage_size;
1293 /* ??? This is gross but the only safe stance in the absence
1294 of stack usage oriented flow analysis. */
1295 if (!cannot_accumulate)
1296 current_function_has_unbounded_dynamic_stack_size = 1;
1299 do_pending_stack_adjust ();
1301 /* We ought to be called always on the toplevel and stack ought to be aligned
1303 gcc_assert (!(stack_pointer_delta
1304 % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)));
1306 /* If needed, check that we have the required amount of stack. Take into
1307 account what has already been checked. */
1308 if (STACK_CHECK_MOVING_SP)
1310 else if (flag_stack_check == GENERIC_STACK_CHECK)
1311 probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE,
1313 else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK)
1314 probe_stack_range (STACK_CHECK_PROTECT, size);
1316 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1317 if (target == 0 || !REG_P (target)
1318 || REGNO (target) < FIRST_PSEUDO_REGISTER
1319 || GET_MODE (target) != Pmode)
1320 target = gen_reg_rtx (Pmode);
1322 mark_reg_pointer (target, known_align);
1324 /* Perform the required allocation from the stack. Some systems do
1325 this differently than simply incrementing/decrementing from the
1326 stack pointer, such as acquiring the space by calling malloc(). */
1327 #ifdef HAVE_allocate_stack
1328 if (HAVE_allocate_stack)
1330 enum machine_mode mode = STACK_SIZE_MODE;
1331 insn_operand_predicate_fn pred;
1333 /* We don't have to check against the predicate for operand 0 since
1334 TARGET is known to be a pseudo of the proper mode, which must
1335 be valid for the operand. For operand 1, convert to the
1336 proper mode and validate. */
1337 if (mode == VOIDmode)
1338 mode = insn_data[(int) CODE_FOR_allocate_stack].operand[1].mode;
1340 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1341 if (pred && ! ((*pred) (size, mode)))
1342 size = copy_to_mode_reg (mode, convert_to_mode (mode, size, 1));
1344 emit_insn (gen_allocate_stack (target, size));
1349 int saved_stack_pointer_delta;
1351 #ifndef STACK_GROWS_DOWNWARD
1352 emit_move_insn (target, virtual_stack_dynamic_rtx);
1355 /* Check stack bounds if necessary. */
1356 if (crtl->limit_stack)
1359 rtx space_available = gen_label_rtx ();
1360 #ifdef STACK_GROWS_DOWNWARD
1361 available = expand_binop (Pmode, sub_optab,
1362 stack_pointer_rtx, stack_limit_rtx,
1363 NULL_RTX, 1, OPTAB_WIDEN);
1365 available = expand_binop (Pmode, sub_optab,
1366 stack_limit_rtx, stack_pointer_rtx,
1367 NULL_RTX, 1, OPTAB_WIDEN);
1369 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1373 emit_insn (gen_trap ());
1376 error ("stack limits not supported on this target");
1378 emit_label (space_available);
1381 saved_stack_pointer_delta = stack_pointer_delta;
1382 if (flag_stack_check && STACK_CHECK_MOVING_SP)
1383 anti_adjust_stack_and_probe (size, false);
1385 anti_adjust_stack (size);
1386 /* Even if size is constant, don't modify stack_pointer_delta.
1387 The constant size alloca should preserve
1388 crtl->preferred_stack_boundary alignment. */
1389 stack_pointer_delta = saved_stack_pointer_delta;
1391 #ifdef STACK_GROWS_DOWNWARD
1392 emit_move_insn (target, virtual_stack_dynamic_rtx);
1398 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1399 but we know it can't. So add ourselves and then do
1401 target = expand_binop (Pmode, add_optab, target,
1402 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1403 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1404 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1405 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1407 target = expand_mult (Pmode, target,
1408 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1412 /* Record the new stack level for nonlocal gotos. */
1413 if (cfun->nonlocal_goto_save_area != 0)
1414 update_nonlocal_goto_save_area ();
1419 /* A front end may want to override GCC's stack checking by providing a
1420 run-time routine to call to check the stack, so provide a mechanism for
1421 calling that routine. */
1423 static GTY(()) rtx stack_check_libfunc;
1426 set_stack_check_libfunc (const char *libfunc_name)
1428 gcc_assert (stack_check_libfunc == NULL_RTX);
1429 stack_check_libfunc = gen_rtx_SYMBOL_REF (Pmode, libfunc_name);
1432 /* Emit one stack probe at ADDRESS, an address within the stack. */
1435 emit_stack_probe (rtx address)
1437 rtx memref = gen_rtx_MEM (word_mode, address);
1439 MEM_VOLATILE_P (memref) = 1;
1441 /* See if we have an insn to probe the stack. */
1442 #ifdef HAVE_probe_stack
1443 if (HAVE_probe_stack)
1444 emit_insn (gen_probe_stack (memref));
1447 emit_move_insn (memref, const0_rtx);
1450 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1451 FIRST is a constant and size is a Pmode RTX. These are offsets from
1452 the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
1453 or subtract them from the stack pointer. */
1455 #define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
1457 #ifdef STACK_GROWS_DOWNWARD
1458 #define STACK_GROW_OP MINUS
1459 #define STACK_GROW_OPTAB sub_optab
1460 #define STACK_GROW_OFF(off) -(off)
1462 #define STACK_GROW_OP PLUS
1463 #define STACK_GROW_OPTAB add_optab
1464 #define STACK_GROW_OFF(off) (off)
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 we have a function to check the stack. */
1475 if (stack_check_libfunc)
1477 rtx addr = memory_address (Pmode,
1478 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1480 plus_constant (size, first)));
1481 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1485 /* Next see if we have an insn to check the stack. */
1486 #ifdef HAVE_check_stack
1487 else if (HAVE_check_stack)
1489 rtx addr = memory_address (Pmode,
1490 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1492 plus_constant (size, first)));
1493 insn_operand_predicate_fn pred
1494 = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1495 if (pred && !((*pred) (addr, Pmode)))
1496 addr = copy_to_mode_reg (Pmode, addr);
1498 emit_insn (gen_check_stack (addr));
1502 /* Otherwise we have to generate explicit probes. If we have a constant
1503 small number of them to generate, that's the easy case. */
1504 else if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
1506 HOST_WIDE_INT isize = INTVAL (size), i;
1509 /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until
1510 it exceeds SIZE. If only one probe is needed, this will not
1511 generate any code. Then probe at FIRST + SIZE. */
1512 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
1514 addr = memory_address (Pmode,
1515 plus_constant (stack_pointer_rtx,
1516 STACK_GROW_OFF (first + i)));
1517 emit_stack_probe (addr);
1520 addr = memory_address (Pmode,
1521 plus_constant (stack_pointer_rtx,
1522 STACK_GROW_OFF (first + isize)));
1523 emit_stack_probe (addr);
1526 /* In the variable case, do the same as above, but in a loop. Note that we
1527 must be extra careful with variables wrapping around because we might be
1528 at the very top (or the very bottom) of the address space and we have to
1529 be able to handle this case properly; in particular, we use an equality
1530 test for the loop condition. */
1533 rtx rounded_size, rounded_size_op, test_addr, last_addr, temp;
1534 rtx loop_lab = gen_label_rtx ();
1535 rtx end_lab = gen_label_rtx ();
1538 /* Step 1: round SIZE to the previous multiple of the interval. */
1540 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1542 = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL));
1543 rounded_size_op = force_operand (rounded_size, NULL_RTX);
1546 /* Step 2: compute initial and final value of the loop counter. */
1548 /* TEST_ADDR = SP + FIRST. */
1549 test_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1551 GEN_INT (first)), NULL_RTX);
1553 /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
1554 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1556 rounded_size_op), NULL_RTX);
1561 while (TEST_ADDR != LAST_ADDR)
1563 TEST_ADDR = TEST_ADDR + PROBE_INTERVAL
1567 probes at FIRST + N * PROBE_INTERVAL for values of N from 1
1568 until it is equal to ROUNDED_SIZE. */
1570 emit_label (loop_lab);
1572 /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
1573 emit_cmp_and_jump_insns (test_addr, last_addr, EQ, NULL_RTX, Pmode, 1,
1576 /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
1577 temp = expand_binop (Pmode, STACK_GROW_OPTAB, test_addr,
1578 GEN_INT (PROBE_INTERVAL), test_addr,
1581 gcc_assert (temp == test_addr);
1583 /* Probe at TEST_ADDR. */
1584 emit_stack_probe (test_addr);
1586 emit_jump (loop_lab);
1588 emit_label (end_lab);
1591 /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
1592 that SIZE is equal to ROUNDED_SIZE. */
1594 /* TEMP = SIZE - ROUNDED_SIZE. */
1595 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
1596 if (temp != const0_rtx)
1600 if (CONST_INT_P (temp))
1602 /* Use [base + disp} addressing mode if supported. */
1603 HOST_WIDE_INT offset = INTVAL (temp);
1604 addr = memory_address (Pmode,
1605 plus_constant (last_addr,
1606 STACK_GROW_OFF (offset)));
1610 /* Manual CSE if the difference is not known at compile-time. */
1611 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
1612 addr = memory_address (Pmode,
1613 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1617 emit_stack_probe (addr);
1622 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
1623 while probing it. This pushes when SIZE is positive. SIZE need not
1624 be constant. If ADJUST_BACK is true, adjust back the stack pointer
1625 by plus SIZE at the end. */
1628 anti_adjust_stack_and_probe (rtx size, bool adjust_back)
1630 /* We skip the probe for the first interval + a small dope of 4 words and
1631 probe that many bytes past the specified size to maintain a protection
1632 area at the botton of the stack. */
1633 const int dope = 4 * UNITS_PER_WORD;
1635 /* First ensure SIZE is Pmode. */
1636 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1637 size = convert_to_mode (Pmode, size, 1);
1639 /* If we have a constant small number of probes to generate, that's the
1641 if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
1643 HOST_WIDE_INT isize = INTVAL (size), i;
1644 bool first_probe = true;
1646 /* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for
1647 values of N from 1 until it exceeds SIZE. If only one probe is
1648 needed, this will not generate any code. Then adjust and probe
1649 to PROBE_INTERVAL + SIZE. */
1650 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
1654 anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL + dope));
1655 first_probe = false;
1658 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
1659 emit_stack_probe (stack_pointer_rtx);
1663 anti_adjust_stack (plus_constant (size, PROBE_INTERVAL + dope));
1665 anti_adjust_stack (plus_constant (size, PROBE_INTERVAL - i));
1666 emit_stack_probe (stack_pointer_rtx);
1669 /* In the variable case, do the same as above, but in a loop. Note that we
1670 must be extra careful with variables wrapping around because we might be
1671 at the very top (or the very bottom) of the address space and we have to
1672 be able to handle this case properly; in particular, we use an equality
1673 test for the loop condition. */
1676 rtx rounded_size, rounded_size_op, last_addr, temp;
1677 rtx loop_lab = gen_label_rtx ();
1678 rtx end_lab = gen_label_rtx ();
1681 /* Step 1: round SIZE to the previous multiple of the interval. */
1683 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1685 = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL));
1686 rounded_size_op = force_operand (rounded_size, NULL_RTX);
1689 /* Step 2: compute initial and final value of the loop counter. */
1691 /* SP = SP_0 + PROBE_INTERVAL. */
1692 anti_adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
1694 /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */
1695 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1697 rounded_size_op), NULL_RTX);
1702 while (SP != LAST_ADDR)
1704 SP = SP + PROBE_INTERVAL
1708 adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for
1709 values of N from 1 until it is equal to ROUNDED_SIZE. */
1711 emit_label (loop_lab);
1713 /* Jump to END_LAB if SP == LAST_ADDR. */
1714 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
1717 /* SP = SP + PROBE_INTERVAL and probe at SP. */
1718 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
1719 emit_stack_probe (stack_pointer_rtx);
1721 emit_jump (loop_lab);
1723 emit_label (end_lab);
1726 /* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot
1727 assert at compile-time that SIZE is equal to ROUNDED_SIZE. */
1729 /* TEMP = SIZE - ROUNDED_SIZE. */
1730 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
1731 if (temp != const0_rtx)
1733 /* Manual CSE if the difference is not known at compile-time. */
1734 if (GET_CODE (temp) != CONST_INT)
1735 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
1736 anti_adjust_stack (temp);
1737 emit_stack_probe (stack_pointer_rtx);
1741 /* Adjust back and account for the additional first interval. */
1743 adjust_stack (plus_constant (size, PROBE_INTERVAL + dope));
1745 adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
1748 /* Return an rtx representing the register or memory location
1749 in which a scalar value of data type VALTYPE
1750 was returned by a function call to function FUNC.
1751 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1752 function is known, otherwise 0.
1753 OUTGOING is 1 if on a machine with register windows this function
1754 should return the register in which the function will put its result
1758 hard_function_value (const_tree valtype, const_tree func, const_tree fntype,
1759 int outgoing ATTRIBUTE_UNUSED)
1763 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing);
1766 && GET_MODE (val) == BLKmode)
1768 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1769 enum machine_mode tmpmode;
1771 /* int_size_in_bytes can return -1. We don't need a check here
1772 since the value of bytes will then be large enough that no
1773 mode will match anyway. */
1775 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1776 tmpmode != VOIDmode;
1777 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1779 /* Have we found a large enough mode? */
1780 if (GET_MODE_SIZE (tmpmode) >= bytes)
1784 /* No suitable mode found. */
1785 gcc_assert (tmpmode != VOIDmode);
1787 PUT_MODE (val, tmpmode);
1792 /* Return an rtx representing the register or memory location
1793 in which a scalar value of mode MODE was returned by a library call. */
1796 hard_libcall_value (enum machine_mode mode, rtx fun)
1798 return targetm.calls.libcall_value (mode, fun);
1801 /* Look up the tree code for a given rtx code
1802 to provide the arithmetic operation for REAL_ARITHMETIC.
1803 The function returns an int because the caller may not know
1804 what `enum tree_code' means. */
1807 rtx_to_tree_code (enum rtx_code code)
1809 enum tree_code tcode;
1832 tcode = LAST_AND_UNUSED_TREE_CODE;
1835 return ((int) tcode);
1838 #include "gt-explow.h"