1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987, 1991, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
3 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
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"
37 #include "hard-reg-set.h"
38 #include "insn-config.h"
41 #include "langhooks.h"
43 #include "common/common-target.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_PRECISION (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 /* Called without a type node for a libcall. */
776 if (type == NULL_TREE)
778 if (INTEGRAL_MODE_P (mode))
779 return targetm.calls.promote_function_mode (NULL_TREE, mode,
786 switch (TREE_CODE (type))
788 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
789 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
790 case POINTER_TYPE: case REFERENCE_TYPE:
791 return targetm.calls.promote_function_mode (type, mode, punsignedp, funtype,
798 /* Return the mode to use to store a scalar of TYPE and MODE.
799 PUNSIGNEDP points to the signedness of the type and may be adjusted
800 to show what signedness to use on extension operations. */
803 promote_mode (const_tree type ATTRIBUTE_UNUSED, enum machine_mode mode,
804 int *punsignedp ATTRIBUTE_UNUSED)
811 /* For libcalls this is invoked without TYPE from the backends
812 TARGET_PROMOTE_FUNCTION_MODE hooks. Don't do anything in that
814 if (type == NULL_TREE)
817 /* FIXME: this is the same logic that was there until GCC 4.4, but we
818 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
819 is not defined. The affected targets are M32C, S390, SPARC. */
821 code = TREE_CODE (type);
822 unsignedp = *punsignedp;
826 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
827 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
828 PROMOTE_MODE (mode, unsignedp, type);
829 *punsignedp = unsignedp;
833 #ifdef POINTERS_EXTEND_UNSIGNED
836 *punsignedp = POINTERS_EXTEND_UNSIGNED;
837 return targetm.addr_space.address_mode
838 (TYPE_ADDR_SPACE (TREE_TYPE (type)));
851 /* Use one of promote_mode or promote_function_mode to find the promoted
852 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
853 of DECL after promotion. */
856 promote_decl_mode (const_tree decl, int *punsignedp)
858 tree type = TREE_TYPE (decl);
859 int unsignedp = TYPE_UNSIGNED (type);
860 enum machine_mode mode = DECL_MODE (decl);
861 enum machine_mode pmode;
863 if (TREE_CODE (decl) == RESULT_DECL
864 || TREE_CODE (decl) == PARM_DECL)
865 pmode = promote_function_mode (type, mode, &unsignedp,
866 TREE_TYPE (current_function_decl), 2);
868 pmode = promote_mode (type, mode, &unsignedp);
871 *punsignedp = unsignedp;
876 /* Controls the behaviour of {anti_,}adjust_stack. */
877 static bool suppress_reg_args_size;
879 /* A helper for adjust_stack and anti_adjust_stack. */
882 adjust_stack_1 (rtx adjust, bool anti_p)
886 #ifndef STACK_GROWS_DOWNWARD
887 /* Hereafter anti_p means subtract_p. */
891 temp = expand_binop (Pmode,
892 anti_p ? sub_optab : add_optab,
893 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
896 if (temp != stack_pointer_rtx)
897 insn = emit_move_insn (stack_pointer_rtx, temp);
900 insn = get_last_insn ();
901 temp = single_set (insn);
902 gcc_assert (temp != NULL && SET_DEST (temp) == stack_pointer_rtx);
905 if (!suppress_reg_args_size)
906 add_reg_note (insn, REG_ARGS_SIZE, GEN_INT (stack_pointer_delta));
909 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
910 This pops when ADJUST is positive. ADJUST need not be constant. */
913 adjust_stack (rtx adjust)
915 if (adjust == const0_rtx)
918 /* We expect all variable sized adjustments to be multiple of
919 PREFERRED_STACK_BOUNDARY. */
920 if (CONST_INT_P (adjust))
921 stack_pointer_delta -= INTVAL (adjust);
923 adjust_stack_1 (adjust, false);
926 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
927 This pushes when ADJUST is positive. ADJUST need not be constant. */
930 anti_adjust_stack (rtx adjust)
932 if (adjust == const0_rtx)
935 /* We expect all variable sized adjustments to be multiple of
936 PREFERRED_STACK_BOUNDARY. */
937 if (CONST_INT_P (adjust))
938 stack_pointer_delta += INTVAL (adjust);
940 adjust_stack_1 (adjust, true);
943 /* Round the size of a block to be pushed up to the boundary required
944 by this machine. SIZE is the desired size, which need not be constant. */
947 round_push (rtx size)
949 rtx align_rtx, alignm1_rtx;
951 if (!SUPPORTS_STACK_ALIGNMENT
952 || crtl->preferred_stack_boundary == MAX_SUPPORTED_STACK_ALIGNMENT)
954 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
959 if (CONST_INT_P (size))
961 HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align;
963 if (INTVAL (size) != new_size)
964 size = GEN_INT (new_size);
968 align_rtx = GEN_INT (align);
969 alignm1_rtx = GEN_INT (align - 1);
973 /* If crtl->preferred_stack_boundary might still grow, use
974 virtual_preferred_stack_boundary_rtx instead. This will be
975 substituted by the right value in vregs pass and optimized
977 align_rtx = virtual_preferred_stack_boundary_rtx;
978 alignm1_rtx = force_operand (plus_constant (align_rtx, -1), NULL_RTX);
981 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
982 but we know it can't. So add ourselves and then do
984 size = expand_binop (Pmode, add_optab, size, alignm1_rtx,
985 NULL_RTX, 1, OPTAB_LIB_WIDEN);
986 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, align_rtx,
988 size = expand_mult (Pmode, size, align_rtx, NULL_RTX, 1);
993 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
994 to a previously-created save area. If no save area has been allocated,
995 this function will allocate one. If a save area is specified, it
996 must be of the proper mode. */
999 emit_stack_save (enum save_level save_level, rtx *psave)
1002 /* The default is that we use a move insn and save in a Pmode object. */
1003 rtx (*fcn) (rtx, rtx) = gen_move_insn;
1004 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
1006 /* See if this machine has anything special to do for this kind of save. */
1009 #ifdef HAVE_save_stack_block
1011 if (HAVE_save_stack_block)
1012 fcn = gen_save_stack_block;
1015 #ifdef HAVE_save_stack_function
1017 if (HAVE_save_stack_function)
1018 fcn = gen_save_stack_function;
1021 #ifdef HAVE_save_stack_nonlocal
1023 if (HAVE_save_stack_nonlocal)
1024 fcn = gen_save_stack_nonlocal;
1031 /* If there is no save area and we have to allocate one, do so. Otherwise
1032 verify the save area is the proper mode. */
1036 if (mode != VOIDmode)
1038 if (save_level == SAVE_NONLOCAL)
1039 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
1041 *psave = sa = gen_reg_rtx (mode);
1045 do_pending_stack_adjust ();
1047 sa = validize_mem (sa);
1048 emit_insn (fcn (sa, stack_pointer_rtx));
1051 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1052 area made by emit_stack_save. If it is zero, we have nothing to do. */
1055 emit_stack_restore (enum save_level save_level, rtx sa)
1057 /* The default is that we use a move insn. */
1058 rtx (*fcn) (rtx, rtx) = gen_move_insn;
1060 /* See if this machine has anything special to do for this kind of save. */
1063 #ifdef HAVE_restore_stack_block
1065 if (HAVE_restore_stack_block)
1066 fcn = gen_restore_stack_block;
1069 #ifdef HAVE_restore_stack_function
1071 if (HAVE_restore_stack_function)
1072 fcn = gen_restore_stack_function;
1075 #ifdef HAVE_restore_stack_nonlocal
1077 if (HAVE_restore_stack_nonlocal)
1078 fcn = gen_restore_stack_nonlocal;
1087 sa = validize_mem (sa);
1088 /* These clobbers prevent the scheduler from moving
1089 references to variable arrays below the code
1090 that deletes (pops) the arrays. */
1091 emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
1092 emit_clobber (gen_rtx_MEM (BLKmode, stack_pointer_rtx));
1095 discard_pending_stack_adjust ();
1097 emit_insn (fcn (stack_pointer_rtx, sa));
1100 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1101 function. This function should be called whenever we allocate or
1102 deallocate dynamic stack space. */
1105 update_nonlocal_goto_save_area (void)
1110 /* The nonlocal_goto_save_area object is an array of N pointers. The
1111 first one is used for the frame pointer save; the rest are sized by
1112 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1113 of the stack save area slots. */
1114 t_save = build4 (ARRAY_REF,
1115 TREE_TYPE (TREE_TYPE (cfun->nonlocal_goto_save_area)),
1116 cfun->nonlocal_goto_save_area,
1117 integer_one_node, NULL_TREE, NULL_TREE);
1118 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1120 emit_stack_save (SAVE_NONLOCAL, &r_save);
1123 /* Return an rtx representing the address of an area of memory dynamically
1124 pushed on the stack.
1126 Any required stack pointer alignment is preserved.
1128 SIZE is an rtx representing the size of the area.
1130 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1131 parameter may be zero. If so, a proper value will be extracted
1132 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1134 REQUIRED_ALIGN is the alignment (in bits) required for the region
1137 If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
1138 stack space allocated by the generated code cannot be added with itself
1139 in the course of the execution of the function. It is always safe to
1140 pass FALSE here and the following criterion is sufficient in order to
1141 pass TRUE: every path in the CFG that starts at the allocation point and
1142 loops to it executes the associated deallocation code. */
1145 allocate_dynamic_stack_space (rtx size, unsigned size_align,
1146 unsigned required_align, bool cannot_accumulate)
1148 HOST_WIDE_INT stack_usage_size = -1;
1149 rtx final_label, final_target, target;
1150 unsigned extra_align = 0;
1153 /* If we're asking for zero bytes, it doesn't matter what we point
1154 to since we can't dereference it. But return a reasonable
1156 if (size == const0_rtx)
1157 return virtual_stack_dynamic_rtx;
1159 /* Otherwise, show we're calling alloca or equivalent. */
1160 cfun->calls_alloca = 1;
1162 /* If stack usage info is requested, look into the size we are passed.
1163 We need to do so this early to avoid the obfuscation that may be
1164 introduced later by the various alignment operations. */
1165 if (flag_stack_usage_info)
1167 if (CONST_INT_P (size))
1168 stack_usage_size = INTVAL (size);
1169 else if (REG_P (size))
1171 /* Look into the last emitted insn and see if we can deduce
1172 something for the register. */
1173 rtx insn, set, note;
1174 insn = get_last_insn ();
1175 if ((set = single_set (insn)) && rtx_equal_p (SET_DEST (set), size))
1177 if (CONST_INT_P (SET_SRC (set)))
1178 stack_usage_size = INTVAL (SET_SRC (set));
1179 else if ((note = find_reg_equal_equiv_note (insn))
1180 && CONST_INT_P (XEXP (note, 0)))
1181 stack_usage_size = INTVAL (XEXP (note, 0));
1185 /* If the size is not constant, we can't say anything. */
1186 if (stack_usage_size == -1)
1188 current_function_has_unbounded_dynamic_stack_size = 1;
1189 stack_usage_size = 0;
1193 /* Ensure the size is in the proper mode. */
1194 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1195 size = convert_to_mode (Pmode, size, 1);
1197 /* Adjust SIZE_ALIGN, if needed. */
1198 if (CONST_INT_P (size))
1200 unsigned HOST_WIDE_INT lsb;
1202 lsb = INTVAL (size);
1205 /* Watch out for overflow truncating to "unsigned". */
1206 if (lsb > UINT_MAX / BITS_PER_UNIT)
1207 size_align = 1u << (HOST_BITS_PER_INT - 1);
1209 size_align = (unsigned)lsb * BITS_PER_UNIT;
1211 else if (size_align < BITS_PER_UNIT)
1212 size_align = BITS_PER_UNIT;
1214 /* We can't attempt to minimize alignment necessary, because we don't
1215 know the final value of preferred_stack_boundary yet while executing
1217 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
1218 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1220 /* We will need to ensure that the address we return is aligned to
1221 REQUIRED_ALIGN. If STACK_DYNAMIC_OFFSET is defined, we don't
1222 always know its final value at this point in the compilation (it
1223 might depend on the size of the outgoing parameter lists, for
1224 example), so we must align the value to be returned in that case.
1225 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1226 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1227 We must also do an alignment operation on the returned value if
1228 the stack pointer alignment is less strict than REQUIRED_ALIGN.
1230 If we have to align, we must leave space in SIZE for the hole
1231 that might result from the alignment operation. */
1233 must_align = (crtl->preferred_stack_boundary < required_align);
1236 if (required_align > PREFERRED_STACK_BOUNDARY)
1237 extra_align = PREFERRED_STACK_BOUNDARY;
1238 else if (required_align > STACK_BOUNDARY)
1239 extra_align = STACK_BOUNDARY;
1241 extra_align = BITS_PER_UNIT;
1244 /* ??? STACK_POINTER_OFFSET is always defined now. */
1245 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1247 extra_align = BITS_PER_UNIT;
1252 unsigned extra = (required_align - extra_align) / BITS_PER_UNIT;
1254 size = plus_constant (size, extra);
1255 size = force_operand (size, NULL_RTX);
1257 if (flag_stack_usage_info)
1258 stack_usage_size += extra;
1260 if (extra && size_align > extra_align)
1261 size_align = extra_align;
1264 /* Round the size to a multiple of the required stack alignment.
1265 Since the stack if presumed to be rounded before this allocation,
1266 this will maintain the required alignment.
1268 If the stack grows downward, we could save an insn by subtracting
1269 SIZE from the stack pointer and then aligning the stack pointer.
1270 The problem with this is that the stack pointer may be unaligned
1271 between the execution of the subtraction and alignment insns and
1272 some machines do not allow this. Even on those that do, some
1273 signal handlers malfunction if a signal should occur between those
1274 insns. Since this is an extremely rare event, we have no reliable
1275 way of knowing which systems have this problem. So we avoid even
1276 momentarily mis-aligning the stack. */
1277 if (size_align % MAX_SUPPORTED_STACK_ALIGNMENT != 0)
1279 size = round_push (size);
1281 if (flag_stack_usage_info)
1283 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
1284 stack_usage_size = (stack_usage_size + align - 1) / align * align;
1288 target = gen_reg_rtx (Pmode);
1290 /* The size is supposed to be fully adjusted at this point so record it
1291 if stack usage info is requested. */
1292 if (flag_stack_usage_info)
1294 current_function_dynamic_stack_size += stack_usage_size;
1296 /* ??? This is gross but the only safe stance in the absence
1297 of stack usage oriented flow analysis. */
1298 if (!cannot_accumulate)
1299 current_function_has_unbounded_dynamic_stack_size = 1;
1302 final_label = NULL_RTX;
1303 final_target = NULL_RTX;
1305 /* If we are splitting the stack, we need to ask the backend whether
1306 there is enough room on the current stack. If there isn't, or if
1307 the backend doesn't know how to tell is, then we need to call a
1308 function to allocate memory in some other way. This memory will
1309 be released when we release the current stack segment. The
1310 effect is that stack allocation becomes less efficient, but at
1311 least it doesn't cause a stack overflow. */
1312 if (flag_split_stack)
1314 rtx available_label, ask, space, func;
1316 available_label = NULL_RTX;
1318 #ifdef HAVE_split_stack_space_check
1319 if (HAVE_split_stack_space_check)
1321 available_label = gen_label_rtx ();
1323 /* This instruction will branch to AVAILABLE_LABEL if there
1324 are SIZE bytes available on the stack. */
1325 emit_insn (gen_split_stack_space_check (size, available_label));
1329 /* The __morestack_allocate_stack_space function will allocate
1330 memory using malloc. If the alignment of the memory returned
1331 by malloc does not meet REQUIRED_ALIGN, we increase SIZE to
1332 make sure we allocate enough space. */
1333 if (MALLOC_ABI_ALIGNMENT >= required_align)
1337 ask = expand_binop (Pmode, add_optab, size,
1338 GEN_INT (required_align / BITS_PER_UNIT - 1),
1339 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1343 func = init_one_libfunc ("__morestack_allocate_stack_space");
1345 space = emit_library_call_value (func, target, LCT_NORMAL, Pmode,
1348 if (available_label == NULL_RTX)
1351 final_target = gen_reg_rtx (Pmode);
1353 emit_move_insn (final_target, space);
1355 final_label = gen_label_rtx ();
1356 emit_jump (final_label);
1358 emit_label (available_label);
1361 do_pending_stack_adjust ();
1363 /* We ought to be called always on the toplevel and stack ought to be aligned
1365 gcc_assert (!(stack_pointer_delta
1366 % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)));
1368 /* If needed, check that we have the required amount of stack. Take into
1369 account what has already been checked. */
1370 if (STACK_CHECK_MOVING_SP)
1372 else if (flag_stack_check == GENERIC_STACK_CHECK)
1373 probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE,
1375 else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK)
1376 probe_stack_range (STACK_CHECK_PROTECT, size);
1378 /* Perform the required allocation from the stack. Some systems do
1379 this differently than simply incrementing/decrementing from the
1380 stack pointer, such as acquiring the space by calling malloc(). */
1381 #ifdef HAVE_allocate_stack
1382 if (HAVE_allocate_stack)
1384 struct expand_operand ops[2];
1385 /* We don't have to check against the predicate for operand 0 since
1386 TARGET is known to be a pseudo of the proper mode, which must
1387 be valid for the operand. */
1388 create_fixed_operand (&ops[0], target);
1389 create_convert_operand_to (&ops[1], size, STACK_SIZE_MODE, true);
1390 expand_insn (CODE_FOR_allocate_stack, 2, ops);
1395 int saved_stack_pointer_delta;
1397 #ifndef STACK_GROWS_DOWNWARD
1398 emit_move_insn (target, virtual_stack_dynamic_rtx);
1401 /* Check stack bounds if necessary. */
1402 if (crtl->limit_stack)
1405 rtx space_available = gen_label_rtx ();
1406 #ifdef STACK_GROWS_DOWNWARD
1407 available = expand_binop (Pmode, sub_optab,
1408 stack_pointer_rtx, stack_limit_rtx,
1409 NULL_RTX, 1, OPTAB_WIDEN);
1411 available = expand_binop (Pmode, sub_optab,
1412 stack_limit_rtx, stack_pointer_rtx,
1413 NULL_RTX, 1, OPTAB_WIDEN);
1415 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1419 emit_insn (gen_trap ());
1422 error ("stack limits not supported on this target");
1424 emit_label (space_available);
1427 saved_stack_pointer_delta = stack_pointer_delta;
1428 suppress_reg_args_size = true;
1430 if (flag_stack_check && STACK_CHECK_MOVING_SP)
1431 anti_adjust_stack_and_probe (size, false);
1433 anti_adjust_stack (size);
1435 /* Even if size is constant, don't modify stack_pointer_delta.
1436 The constant size alloca should preserve
1437 crtl->preferred_stack_boundary alignment. */
1438 stack_pointer_delta = saved_stack_pointer_delta;
1439 suppress_reg_args_size = false;
1441 #ifdef STACK_GROWS_DOWNWARD
1442 emit_move_insn (target, virtual_stack_dynamic_rtx);
1446 /* Finish up the split stack handling. */
1447 if (final_label != NULL_RTX)
1449 gcc_assert (flag_split_stack);
1450 emit_move_insn (final_target, target);
1451 emit_label (final_label);
1452 target = final_target;
1457 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1458 but we know it can't. So add ourselves and then do
1460 target = expand_binop (Pmode, add_optab, target,
1461 GEN_INT (required_align / BITS_PER_UNIT - 1),
1462 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1463 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1464 GEN_INT (required_align / BITS_PER_UNIT),
1466 target = expand_mult (Pmode, target,
1467 GEN_INT (required_align / BITS_PER_UNIT),
1471 /* Now that we've committed to a return value, mark its alignment. */
1472 mark_reg_pointer (target, required_align);
1474 /* Record the new stack level for nonlocal gotos. */
1475 if (cfun->nonlocal_goto_save_area != 0)
1476 update_nonlocal_goto_save_area ();
1481 /* A front end may want to override GCC's stack checking by providing a
1482 run-time routine to call to check the stack, so provide a mechanism for
1483 calling that routine. */
1485 static GTY(()) rtx stack_check_libfunc;
1488 set_stack_check_libfunc (const char *libfunc_name)
1490 gcc_assert (stack_check_libfunc == NULL_RTX);
1491 stack_check_libfunc = gen_rtx_SYMBOL_REF (Pmode, libfunc_name);
1494 /* Emit one stack probe at ADDRESS, an address within the stack. */
1497 emit_stack_probe (rtx address)
1499 rtx memref = gen_rtx_MEM (word_mode, address);
1501 MEM_VOLATILE_P (memref) = 1;
1503 /* See if we have an insn to probe the stack. */
1504 #ifdef HAVE_probe_stack
1505 if (HAVE_probe_stack)
1506 emit_insn (gen_probe_stack (memref));
1509 emit_move_insn (memref, const0_rtx);
1512 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1513 FIRST is a constant and size is a Pmode RTX. These are offsets from
1514 the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
1515 or subtract them from the stack pointer. */
1517 #define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
1519 #ifdef STACK_GROWS_DOWNWARD
1520 #define STACK_GROW_OP MINUS
1521 #define STACK_GROW_OPTAB sub_optab
1522 #define STACK_GROW_OFF(off) -(off)
1524 #define STACK_GROW_OP PLUS
1525 #define STACK_GROW_OPTAB add_optab
1526 #define STACK_GROW_OFF(off) (off)
1530 probe_stack_range (HOST_WIDE_INT first, rtx size)
1532 /* First ensure SIZE is Pmode. */
1533 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1534 size = convert_to_mode (Pmode, size, 1);
1536 /* Next see if we have a function to check the stack. */
1537 if (stack_check_libfunc)
1539 rtx addr = memory_address (Pmode,
1540 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1542 plus_constant (size, first)));
1543 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1548 /* Next see if we have an insn to check the stack. */
1549 #ifdef HAVE_check_stack
1550 if (HAVE_check_stack)
1552 struct expand_operand ops[1];
1553 rtx addr = memory_address (Pmode,
1554 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1556 plus_constant (size, first)));
1558 create_input_operand (&ops[0], addr, Pmode);
1559 if (maybe_expand_insn (CODE_FOR_check_stack, 1, ops))
1564 /* Otherwise we have to generate explicit probes. If we have a constant
1565 small number of them to generate, that's the easy case. */
1566 else if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
1568 HOST_WIDE_INT isize = INTVAL (size), i;
1571 /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until
1572 it exceeds SIZE. If only one probe is needed, this will not
1573 generate any code. Then probe at FIRST + SIZE. */
1574 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
1576 addr = memory_address (Pmode,
1577 plus_constant (stack_pointer_rtx,
1578 STACK_GROW_OFF (first + i)));
1579 emit_stack_probe (addr);
1582 addr = memory_address (Pmode,
1583 plus_constant (stack_pointer_rtx,
1584 STACK_GROW_OFF (first + isize)));
1585 emit_stack_probe (addr);
1588 /* In the variable case, do the same as above, but in a loop. Note that we
1589 must be extra careful with variables wrapping around because we might be
1590 at the very top (or the very bottom) of the address space and we have to
1591 be able to handle this case properly; in particular, we use an equality
1592 test for the loop condition. */
1595 rtx rounded_size, rounded_size_op, test_addr, last_addr, temp;
1596 rtx loop_lab = gen_label_rtx ();
1597 rtx end_lab = gen_label_rtx ();
1600 /* Step 1: round SIZE to the previous multiple of the interval. */
1602 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1604 = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL));
1605 rounded_size_op = force_operand (rounded_size, NULL_RTX);
1608 /* Step 2: compute initial and final value of the loop counter. */
1610 /* TEST_ADDR = SP + FIRST. */
1611 test_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1613 GEN_INT (first)), NULL_RTX);
1615 /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
1616 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1618 rounded_size_op), NULL_RTX);
1623 while (TEST_ADDR != LAST_ADDR)
1625 TEST_ADDR = TEST_ADDR + PROBE_INTERVAL
1629 probes at FIRST + N * PROBE_INTERVAL for values of N from 1
1630 until it is equal to ROUNDED_SIZE. */
1632 emit_label (loop_lab);
1634 /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
1635 emit_cmp_and_jump_insns (test_addr, last_addr, EQ, NULL_RTX, Pmode, 1,
1638 /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
1639 temp = expand_binop (Pmode, STACK_GROW_OPTAB, test_addr,
1640 GEN_INT (PROBE_INTERVAL), test_addr,
1643 gcc_assert (temp == test_addr);
1645 /* Probe at TEST_ADDR. */
1646 emit_stack_probe (test_addr);
1648 emit_jump (loop_lab);
1650 emit_label (end_lab);
1653 /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
1654 that SIZE is equal to ROUNDED_SIZE. */
1656 /* TEMP = SIZE - ROUNDED_SIZE. */
1657 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
1658 if (temp != const0_rtx)
1662 if (CONST_INT_P (temp))
1664 /* Use [base + disp} addressing mode if supported. */
1665 HOST_WIDE_INT offset = INTVAL (temp);
1666 addr = memory_address (Pmode,
1667 plus_constant (last_addr,
1668 STACK_GROW_OFF (offset)));
1672 /* Manual CSE if the difference is not known at compile-time. */
1673 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
1674 addr = memory_address (Pmode,
1675 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1679 emit_stack_probe (addr);
1684 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
1685 while probing it. This pushes when SIZE is positive. SIZE need not
1686 be constant. If ADJUST_BACK is true, adjust back the stack pointer
1687 by plus SIZE at the end. */
1690 anti_adjust_stack_and_probe (rtx size, bool adjust_back)
1692 /* We skip the probe for the first interval + a small dope of 4 words and
1693 probe that many bytes past the specified size to maintain a protection
1694 area at the botton of the stack. */
1695 const int dope = 4 * UNITS_PER_WORD;
1697 /* First ensure SIZE is Pmode. */
1698 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1699 size = convert_to_mode (Pmode, size, 1);
1701 /* If we have a constant small number of probes to generate, that's the
1703 if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
1705 HOST_WIDE_INT isize = INTVAL (size), i;
1706 bool first_probe = true;
1708 /* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for
1709 values of N from 1 until it exceeds SIZE. If only one probe is
1710 needed, this will not generate any code. Then adjust and probe
1711 to PROBE_INTERVAL + SIZE. */
1712 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
1716 anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL + dope));
1717 first_probe = false;
1720 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
1721 emit_stack_probe (stack_pointer_rtx);
1725 anti_adjust_stack (plus_constant (size, PROBE_INTERVAL + dope));
1727 anti_adjust_stack (plus_constant (size, PROBE_INTERVAL - i));
1728 emit_stack_probe (stack_pointer_rtx);
1731 /* In the variable case, do the same as above, but in a loop. Note that we
1732 must be extra careful with variables wrapping around because we might be
1733 at the very top (or the very bottom) of the address space and we have to
1734 be able to handle this case properly; in particular, we use an equality
1735 test for the loop condition. */
1738 rtx rounded_size, rounded_size_op, last_addr, temp;
1739 rtx loop_lab = gen_label_rtx ();
1740 rtx end_lab = gen_label_rtx ();
1743 /* Step 1: round SIZE to the previous multiple of the interval. */
1745 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1747 = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL));
1748 rounded_size_op = force_operand (rounded_size, NULL_RTX);
1751 /* Step 2: compute initial and final value of the loop counter. */
1753 /* SP = SP_0 + PROBE_INTERVAL. */
1754 anti_adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
1756 /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */
1757 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1759 rounded_size_op), NULL_RTX);
1764 while (SP != LAST_ADDR)
1766 SP = SP + PROBE_INTERVAL
1770 adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for
1771 values of N from 1 until it is equal to ROUNDED_SIZE. */
1773 emit_label (loop_lab);
1775 /* Jump to END_LAB if SP == LAST_ADDR. */
1776 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
1779 /* SP = SP + PROBE_INTERVAL and probe at SP. */
1780 anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
1781 emit_stack_probe (stack_pointer_rtx);
1783 emit_jump (loop_lab);
1785 emit_label (end_lab);
1788 /* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot
1789 assert at compile-time that SIZE is equal to ROUNDED_SIZE. */
1791 /* TEMP = SIZE - ROUNDED_SIZE. */
1792 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
1793 if (temp != const0_rtx)
1795 /* Manual CSE if the difference is not known at compile-time. */
1796 if (GET_CODE (temp) != CONST_INT)
1797 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
1798 anti_adjust_stack (temp);
1799 emit_stack_probe (stack_pointer_rtx);
1803 /* Adjust back and account for the additional first interval. */
1805 adjust_stack (plus_constant (size, PROBE_INTERVAL + dope));
1807 adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
1810 /* Return an rtx representing the register or memory location
1811 in which a scalar value of data type VALTYPE
1812 was returned by a function call to function FUNC.
1813 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1814 function is known, otherwise 0.
1815 OUTGOING is 1 if on a machine with register windows this function
1816 should return the register in which the function will put its result
1820 hard_function_value (const_tree valtype, const_tree func, const_tree fntype,
1821 int outgoing ATTRIBUTE_UNUSED)
1825 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing);
1828 && GET_MODE (val) == BLKmode)
1830 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1831 enum machine_mode tmpmode;
1833 /* int_size_in_bytes can return -1. We don't need a check here
1834 since the value of bytes will then be large enough that no
1835 mode will match anyway. */
1837 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1838 tmpmode != VOIDmode;
1839 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1841 /* Have we found a large enough mode? */
1842 if (GET_MODE_SIZE (tmpmode) >= bytes)
1846 /* No suitable mode found. */
1847 gcc_assert (tmpmode != VOIDmode);
1849 PUT_MODE (val, tmpmode);
1854 /* Return an rtx representing the register or memory location
1855 in which a scalar value of mode MODE was returned by a library call. */
1858 hard_libcall_value (enum machine_mode mode, rtx fun)
1860 return targetm.calls.libcall_value (mode, fun);
1863 /* Look up the tree code for a given rtx code
1864 to provide the arithmetic operation for REAL_ARITHMETIC.
1865 The function returns an int because the caller may not know
1866 what `enum tree_code' means. */
1869 rtx_to_tree_code (enum rtx_code code)
1871 enum tree_code tcode;
1894 tcode = LAST_AND_UNUSED_TREE_CODE;
1897 return ((int) tcode);
1900 #include "gt-explow.h"