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"
36 #include "hard-reg-set.h"
37 #include "insn-config.h"
40 #include "langhooks.h"
44 static rtx break_out_memory_refs (rtx);
45 static void emit_stack_probe (rtx);
48 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
51 trunc_int_for_mode (HOST_WIDE_INT c, enum machine_mode mode)
53 int width = GET_MODE_BITSIZE (mode);
55 /* You want to truncate to a _what_? */
56 gcc_assert (SCALAR_INT_MODE_P (mode));
58 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
60 return c & 1 ? STORE_FLAG_VALUE : 0;
62 /* Sign-extend for the requested mode. */
64 if (width < HOST_BITS_PER_WIDE_INT)
66 HOST_WIDE_INT sign = 1;
76 /* Return an rtx for the sum of X and the integer C. */
79 plus_constant (rtx x, HOST_WIDE_INT c)
83 enum machine_mode mode;
99 return GEN_INT (INTVAL (x) + c);
103 unsigned HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
104 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
105 unsigned HOST_WIDE_INT l2 = c;
106 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
107 unsigned HOST_WIDE_INT lv;
110 add_double (l1, h1, l2, h2, &lv, &hv);
112 return immed_double_const (lv, hv, VOIDmode);
116 /* If this is a reference to the constant pool, try replacing it with
117 a reference to a new constant. If the resulting address isn't
118 valid, don't return it because we have no way to validize it. */
119 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
120 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
123 = force_const_mem (GET_MODE (x),
124 plus_constant (get_pool_constant (XEXP (x, 0)),
126 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
132 /* If adding to something entirely constant, set a flag
133 so that we can add a CONST around the result. */
144 /* The interesting case is adding the integer to a sum.
145 Look for constant term in the sum and combine
146 with C. For an integer constant term, we make a combined
147 integer. For a constant term that is not an explicit integer,
148 we cannot really combine, but group them together anyway.
150 Restart or use a recursive call in case the remaining operand is
151 something that we handle specially, such as a SYMBOL_REF.
153 We may not immediately return from the recursive call here, lest
154 all_constant gets lost. */
156 if (CONST_INT_P (XEXP (x, 1)))
158 c += INTVAL (XEXP (x, 1));
160 if (GET_MODE (x) != VOIDmode)
161 c = trunc_int_for_mode (c, GET_MODE (x));
166 else if (CONSTANT_P (XEXP (x, 1)))
168 x = gen_rtx_PLUS (mode, XEXP (x, 0), plus_constant (XEXP (x, 1), c));
171 else if (find_constant_term_loc (&y))
173 /* We need to be careful since X may be shared and we can't
174 modify it in place. */
175 rtx copy = copy_rtx (x);
176 rtx *const_loc = find_constant_term_loc (©);
178 *const_loc = plus_constant (*const_loc, c);
189 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
191 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
193 else if (all_constant)
194 return gen_rtx_CONST (mode, x);
199 /* If X is a sum, return a new sum like X but lacking any constant terms.
200 Add all the removed constant terms into *CONSTPTR.
201 X itself is not altered. The result != X if and only if
202 it is not isomorphic to X. */
205 eliminate_constant_term (rtx x, rtx *constptr)
210 if (GET_CODE (x) != PLUS)
213 /* First handle constants appearing at this level explicitly. */
214 if (CONST_INT_P (XEXP (x, 1))
215 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
217 && CONST_INT_P (tem))
220 return eliminate_constant_term (XEXP (x, 0), constptr);
224 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
225 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
226 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
227 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
229 && CONST_INT_P (tem))
232 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
238 /* Return an rtx for the size in bytes of the value of EXP. */
245 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
246 size = TREE_OPERAND (exp, 1);
249 size = lang_hooks.expr_size (exp);
251 gcc_assert (size == SUBSTITUTE_PLACEHOLDER_IN_EXPR (size, exp));
254 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), EXPAND_NORMAL);
257 /* Return a wide integer for the size in bytes of the value of EXP, or -1
258 if the size can vary or is larger than an integer. */
261 int_expr_size (tree exp)
265 if (TREE_CODE (exp) == WITH_SIZE_EXPR)
266 size = TREE_OPERAND (exp, 1);
269 size = lang_hooks.expr_size (exp);
273 if (size == 0 || !host_integerp (size, 0))
276 return tree_low_cst (size, 0);
279 /* Return a copy of X in which all memory references
280 and all constants that involve symbol refs
281 have been replaced with new temporary registers.
282 Also emit code to load the memory locations and constants
283 into those registers.
285 If X contains no such constants or memory references,
286 X itself (not a copy) is returned.
288 If a constant is found in the address that is not a legitimate constant
289 in an insn, it is left alone in the hope that it might be valid in the
292 X may contain no arithmetic except addition, subtraction and multiplication.
293 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
296 break_out_memory_refs (rtx x)
299 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
300 && GET_MODE (x) != VOIDmode))
301 x = force_reg (GET_MODE (x), x);
302 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
303 || GET_CODE (x) == MULT)
305 rtx op0 = break_out_memory_refs (XEXP (x, 0));
306 rtx op1 = break_out_memory_refs (XEXP (x, 1));
308 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
309 x = simplify_gen_binary (GET_CODE (x), Pmode, op0, op1);
315 /* Given X, a memory address in ptr_mode, convert it to an address
316 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
317 the fact that pointers are not allowed to overflow by commuting arithmetic
318 operations over conversions so that address arithmetic insns can be
322 convert_memory_address (enum machine_mode to_mode ATTRIBUTE_UNUSED,
325 #ifndef POINTERS_EXTEND_UNSIGNED
326 gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode);
328 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
329 enum machine_mode from_mode;
333 /* If X already has the right mode, just return it. */
334 if (GET_MODE (x) == to_mode)
337 from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
339 /* Here we handle some special cases. If none of them apply, fall through
340 to the default case. */
341 switch (GET_CODE (x))
345 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
347 else if (POINTERS_EXTEND_UNSIGNED < 0)
349 else if (POINTERS_EXTEND_UNSIGNED > 0)
353 temp = simplify_unary_operation (code, to_mode, x, from_mode);
359 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
360 && GET_MODE (SUBREG_REG (x)) == to_mode)
361 return SUBREG_REG (x);
365 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
366 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
371 temp = shallow_copy_rtx (x);
372 PUT_MODE (temp, to_mode);
377 return gen_rtx_CONST (to_mode,
378 convert_memory_address (to_mode, XEXP (x, 0)));
383 /* For addition we can safely permute the conversion and addition
384 operation if one operand is a constant and converting the constant
385 does not change it or if one operand is a constant and we are
386 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
387 We can always safely permute them if we are making the address
389 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
390 || (GET_CODE (x) == PLUS
391 && CONST_INT_P (XEXP (x, 1))
392 && (XEXP (x, 1) == convert_memory_address (to_mode, XEXP (x, 1))
393 || POINTERS_EXTEND_UNSIGNED < 0)))
394 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
395 convert_memory_address (to_mode, XEXP (x, 0)),
403 return convert_modes (to_mode, from_mode,
404 x, POINTERS_EXTEND_UNSIGNED);
405 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
408 /* Return something equivalent to X but valid as a memory address
409 for something of mode MODE. When X is not itself valid, this
410 works by copying X or subexpressions of it into registers. */
413 memory_address (enum machine_mode mode, rtx x)
417 x = convert_memory_address (Pmode, x);
419 /* By passing constant addresses through registers
420 we get a chance to cse them. */
421 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
422 x = force_reg (Pmode, x);
424 /* We get better cse by rejecting indirect addressing at this stage.
425 Let the combiner create indirect addresses where appropriate.
426 For now, generate the code so that the subexpressions useful to share
427 are visible. But not if cse won't be done! */
430 if (! cse_not_expected && !REG_P (x))
431 x = break_out_memory_refs (x);
433 /* At this point, any valid address is accepted. */
434 if (memory_address_p (mode, x))
437 /* If it was valid before but breaking out memory refs invalidated it,
438 use it the old way. */
439 if (memory_address_p (mode, oldx))
445 /* Perform machine-dependent transformations on X
446 in certain cases. This is not necessary since the code
447 below can handle all possible cases, but machine-dependent
448 transformations can make better code. */
451 x = targetm.legitimize_address (x, oldx, mode);
452 if (orig_x != x && memory_address_p (mode, x))
456 /* PLUS and MULT can appear in special ways
457 as the result of attempts to make an address usable for indexing.
458 Usually they are dealt with by calling force_operand, below.
459 But a sum containing constant terms is special
460 if removing them makes the sum a valid address:
461 then we generate that address in a register
462 and index off of it. We do this because it often makes
463 shorter code, and because the addresses thus generated
464 in registers often become common subexpressions. */
465 if (GET_CODE (x) == PLUS)
467 rtx constant_term = const0_rtx;
468 rtx y = eliminate_constant_term (x, &constant_term);
469 if (constant_term == const0_rtx
470 || ! memory_address_p (mode, y))
471 x = force_operand (x, NULL_RTX);
474 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
475 if (! memory_address_p (mode, y))
476 x = force_operand (x, NULL_RTX);
482 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
483 x = force_operand (x, NULL_RTX);
485 /* If we have a register that's an invalid address,
486 it must be a hard reg of the wrong class. Copy it to a pseudo. */
490 /* Last resort: copy the value to a register, since
491 the register is a valid address. */
493 x = force_reg (Pmode, x);
498 gcc_assert (memory_address_p (mode, x));
499 /* If we didn't change the address, we are done. Otherwise, mark
500 a reg as a pointer if we have REG or REG + CONST_INT. */
504 mark_reg_pointer (x, BITS_PER_UNIT);
505 else if (GET_CODE (x) == PLUS
506 && REG_P (XEXP (x, 0))
507 && CONST_INT_P (XEXP (x, 1)))
508 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
510 /* OLDX may have been the address on a temporary. Update the address
511 to indicate that X is now used. */
512 update_temp_slot_address (oldx, x);
517 /* Convert a mem ref into one with a valid memory address.
518 Pass through anything else unchanged. */
521 validize_mem (rtx ref)
525 ref = use_anchored_address (ref);
526 if (memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
529 /* Don't alter REF itself, since that is probably a stack slot. */
530 return replace_equiv_address (ref, XEXP (ref, 0));
533 /* If X is a memory reference to a member of an object block, try rewriting
534 it to use an anchor instead. Return the new memory reference on success
535 and the old one on failure. */
538 use_anchored_address (rtx x)
541 HOST_WIDE_INT offset;
543 if (!flag_section_anchors)
549 /* Split the address into a base and offset. */
552 if (GET_CODE (base) == CONST
553 && GET_CODE (XEXP (base, 0)) == PLUS
554 && CONST_INT_P (XEXP (XEXP (base, 0), 1)))
556 offset += INTVAL (XEXP (XEXP (base, 0), 1));
557 base = XEXP (XEXP (base, 0), 0);
560 /* Check whether BASE is suitable for anchors. */
561 if (GET_CODE (base) != SYMBOL_REF
562 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base)
563 || SYMBOL_REF_ANCHOR_P (base)
564 || SYMBOL_REF_BLOCK (base) == NULL
565 || !targetm.use_anchors_for_symbol_p (base))
568 /* Decide where BASE is going to be. */
569 place_block_symbol (base);
571 /* Get the anchor we need to use. */
572 offset += SYMBOL_REF_BLOCK_OFFSET (base);
573 base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset,
574 SYMBOL_REF_TLS_MODEL (base));
576 /* Work out the offset from the anchor. */
577 offset -= SYMBOL_REF_BLOCK_OFFSET (base);
579 /* If we're going to run a CSE pass, force the anchor into a register.
580 We will then be able to reuse registers for several accesses, if the
581 target costs say that that's worthwhile. */
582 if (!cse_not_expected)
583 base = force_reg (GET_MODE (base), base);
585 return replace_equiv_address (x, plus_constant (base, offset));
588 /* Copy the value or contents of X to a new temp reg and return that reg. */
593 rtx temp = gen_reg_rtx (GET_MODE (x));
595 /* If not an operand, must be an address with PLUS and MULT so
596 do the computation. */
597 if (! general_operand (x, VOIDmode))
598 x = force_operand (x, temp);
601 emit_move_insn (temp, x);
606 /* Like copy_to_reg but always give the new register mode Pmode
607 in case X is a constant. */
610 copy_addr_to_reg (rtx x)
612 return copy_to_mode_reg (Pmode, x);
615 /* Like copy_to_reg but always give the new register mode MODE
616 in case X is a constant. */
619 copy_to_mode_reg (enum machine_mode mode, rtx x)
621 rtx temp = gen_reg_rtx (mode);
623 /* If not an operand, must be an address with PLUS and MULT so
624 do the computation. */
625 if (! general_operand (x, VOIDmode))
626 x = force_operand (x, temp);
628 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode);
630 emit_move_insn (temp, x);
634 /* Load X into a register if it is not already one.
635 Use mode MODE for the register.
636 X should be valid for mode MODE, but it may be a constant which
637 is valid for all integer modes; that's why caller must specify MODE.
639 The caller must not alter the value in the register we return,
640 since we mark it as a "constant" register. */
643 force_reg (enum machine_mode mode, rtx x)
650 if (general_operand (x, mode))
652 temp = gen_reg_rtx (mode);
653 insn = emit_move_insn (temp, x);
657 temp = force_operand (x, NULL_RTX);
659 insn = get_last_insn ();
662 rtx temp2 = gen_reg_rtx (mode);
663 insn = emit_move_insn (temp2, temp);
668 /* Let optimizers know that TEMP's value never changes
669 and that X can be substituted for it. Don't get confused
670 if INSN set something else (such as a SUBREG of TEMP). */
672 && (set = single_set (insn)) != 0
673 && SET_DEST (set) == temp
674 && ! rtx_equal_p (x, SET_SRC (set)))
675 set_unique_reg_note (insn, REG_EQUAL, x);
677 /* Let optimizers know that TEMP is a pointer, and if so, the
678 known alignment of that pointer. */
681 if (GET_CODE (x) == SYMBOL_REF)
683 align = BITS_PER_UNIT;
684 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
685 align = DECL_ALIGN (SYMBOL_REF_DECL (x));
687 else if (GET_CODE (x) == LABEL_REF)
688 align = BITS_PER_UNIT;
689 else if (GET_CODE (x) == CONST
690 && GET_CODE (XEXP (x, 0)) == PLUS
691 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
692 && CONST_INT_P (XEXP (XEXP (x, 0), 1)))
694 rtx s = XEXP (XEXP (x, 0), 0);
695 rtx c = XEXP (XEXP (x, 0), 1);
699 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
700 sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
702 ca = exact_log2 (INTVAL (c) & -INTVAL (c)) * BITS_PER_UNIT;
704 align = MIN (sa, ca);
707 if (align || (MEM_P (x) && MEM_POINTER (x)))
708 mark_reg_pointer (temp, align);
714 /* If X is a memory ref, copy its contents to a new temp reg and return
715 that reg. Otherwise, return X. */
718 force_not_mem (rtx x)
722 if (!MEM_P (x) || GET_MODE (x) == BLKmode)
725 temp = gen_reg_rtx (GET_MODE (x));
728 REG_POINTER (temp) = 1;
730 emit_move_insn (temp, x);
734 /* Copy X to TARGET (if it's nonzero and a reg)
735 or to a new temp reg and return that reg.
736 MODE is the mode to use for X in case it is a constant. */
739 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode)
743 if (target && REG_P (target))
746 temp = gen_reg_rtx (mode);
748 emit_move_insn (temp, x);
752 /* Return the mode to use to pass or return a scalar of TYPE and MODE.
753 PUNSIGNEDP points to the signedness of the type and may be adjusted
754 to show what signedness to use on extension operations.
756 FOR_RETURN is nonzero if the caller is promoting the return value
757 of FNDECL, else it is for promoting args. */
760 promote_function_mode (const_tree type, enum machine_mode mode, int *punsignedp,
761 const_tree funtype, int for_return)
763 gcc_assert (GET_MODE_CLASS (mode) != MODE_COMPLEX_INT);
764 switch (TREE_CODE (type))
766 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
767 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
768 case POINTER_TYPE: case REFERENCE_TYPE:
769 return targetm.calls.promote_function_mode (type, mode, punsignedp, funtype,
776 /* Return the mode to use to store a scalar of TYPE and MODE.
777 PUNSIGNEDP points to the signedness of the type and may be adjusted
778 to show what signedness to use on extension operations. */
781 promote_mode (const_tree type, enum machine_mode mode, int *punsignedp)
783 /* FIXME: this is the same logic that was there until GCC 4.4, but we
784 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
785 is not defined. The affected targets are M32C, S390, SPARC. */
787 const enum tree_code code = TREE_CODE (type);
788 int unsignedp = *punsignedp;
792 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
793 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
794 PROMOTE_MODE (mode, unsignedp, type);
795 *punsignedp = unsignedp;
799 #ifdef POINTERS_EXTEND_UNSIGNED
802 *punsignedp = POINTERS_EXTEND_UNSIGNED;
816 /* Use one of promote_mode or promote_function_mode to find the promoted
817 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
818 of DECL after promotion. */
821 promote_decl_mode (const_tree decl, int *punsignedp)
823 tree type = TREE_TYPE (decl);
824 int unsignedp = TYPE_UNSIGNED (type);
825 enum machine_mode mode = DECL_MODE (decl);
826 enum machine_mode pmode;
828 if (TREE_CODE (decl) == RESULT_DECL)
829 pmode = promote_function_mode (type, mode, &unsignedp,
830 TREE_TYPE (current_function_decl), 1);
831 else if (TREE_CODE (decl) == PARM_DECL)
832 pmode = promote_function_mode (type, mode, &unsignedp,
833 TREE_TYPE (current_function_decl), 0);
835 pmode = promote_mode (type, mode, &unsignedp);
838 *punsignedp = unsignedp;
843 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
844 This pops when ADJUST is positive. ADJUST need not be constant. */
847 adjust_stack (rtx adjust)
851 if (adjust == const0_rtx)
854 /* We expect all variable sized adjustments to be multiple of
855 PREFERRED_STACK_BOUNDARY. */
856 if (CONST_INT_P (adjust))
857 stack_pointer_delta -= INTVAL (adjust);
859 temp = expand_binop (Pmode,
860 #ifdef STACK_GROWS_DOWNWARD
865 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
868 if (temp != stack_pointer_rtx)
869 emit_move_insn (stack_pointer_rtx, temp);
872 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
873 This pushes when ADJUST is positive. ADJUST need not be constant. */
876 anti_adjust_stack (rtx adjust)
880 if (adjust == const0_rtx)
883 /* We expect all variable sized adjustments to be multiple of
884 PREFERRED_STACK_BOUNDARY. */
885 if (CONST_INT_P (adjust))
886 stack_pointer_delta += INTVAL (adjust);
888 temp = expand_binop (Pmode,
889 #ifdef STACK_GROWS_DOWNWARD
894 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
897 if (temp != stack_pointer_rtx)
898 emit_move_insn (stack_pointer_rtx, temp);
901 /* Round the size of a block to be pushed up to the boundary required
902 by this machine. SIZE is the desired size, which need not be constant. */
905 round_push (rtx size)
907 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
912 if (CONST_INT_P (size))
914 HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align;
916 if (INTVAL (size) != new_size)
917 size = GEN_INT (new_size);
921 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
922 but we know it can't. So add ourselves and then do
924 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
925 NULL_RTX, 1, OPTAB_LIB_WIDEN);
926 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
928 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
934 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
935 to a previously-created save area. If no save area has been allocated,
936 this function will allocate one. If a save area is specified, it
937 must be of the proper mode.
939 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
940 are emitted at the current position. */
943 emit_stack_save (enum save_level save_level, rtx *psave, rtx after)
946 /* The default is that we use a move insn and save in a Pmode object. */
947 rtx (*fcn) (rtx, rtx) = gen_move_insn;
948 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
950 /* See if this machine has anything special to do for this kind of save. */
953 #ifdef HAVE_save_stack_block
955 if (HAVE_save_stack_block)
956 fcn = gen_save_stack_block;
959 #ifdef HAVE_save_stack_function
961 if (HAVE_save_stack_function)
962 fcn = gen_save_stack_function;
965 #ifdef HAVE_save_stack_nonlocal
967 if (HAVE_save_stack_nonlocal)
968 fcn = gen_save_stack_nonlocal;
975 /* If there is no save area and we have to allocate one, do so. Otherwise
976 verify the save area is the proper mode. */
980 if (mode != VOIDmode)
982 if (save_level == SAVE_NONLOCAL)
983 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
985 *psave = sa = gen_reg_rtx (mode);
994 do_pending_stack_adjust ();
995 /* We must validize inside the sequence, to ensure that any instructions
996 created by the validize call also get moved to the right place. */
998 sa = validize_mem (sa);
999 emit_insn (fcn (sa, stack_pointer_rtx));
1002 emit_insn_after (seq, after);
1006 do_pending_stack_adjust ();
1008 sa = validize_mem (sa);
1009 emit_insn (fcn (sa, stack_pointer_rtx));
1013 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1014 area made by emit_stack_save. If it is zero, we have nothing to do.
1016 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1017 current position. */
1020 emit_stack_restore (enum save_level save_level, rtx sa, rtx after)
1022 /* The default is that we use a move insn. */
1023 rtx (*fcn) (rtx, rtx) = gen_move_insn;
1025 /* See if this machine has anything special to do for this kind of save. */
1028 #ifdef HAVE_restore_stack_block
1030 if (HAVE_restore_stack_block)
1031 fcn = gen_restore_stack_block;
1034 #ifdef HAVE_restore_stack_function
1036 if (HAVE_restore_stack_function)
1037 fcn = gen_restore_stack_function;
1040 #ifdef HAVE_restore_stack_nonlocal
1042 if (HAVE_restore_stack_nonlocal)
1043 fcn = gen_restore_stack_nonlocal;
1052 sa = validize_mem (sa);
1053 /* These clobbers prevent the scheduler from moving
1054 references to variable arrays below the code
1055 that deletes (pops) the arrays. */
1056 emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
1057 emit_clobber (gen_rtx_MEM (BLKmode, stack_pointer_rtx));
1060 discard_pending_stack_adjust ();
1067 emit_insn (fcn (stack_pointer_rtx, sa));
1070 emit_insn_after (seq, after);
1073 emit_insn (fcn (stack_pointer_rtx, sa));
1076 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1077 function. This function should be called whenever we allocate or
1078 deallocate dynamic stack space. */
1081 update_nonlocal_goto_save_area (void)
1086 /* The nonlocal_goto_save_area object is an array of N pointers. The
1087 first one is used for the frame pointer save; the rest are sized by
1088 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1089 of the stack save area slots. */
1090 t_save = build4 (ARRAY_REF, ptr_type_node, cfun->nonlocal_goto_save_area,
1091 integer_one_node, NULL_TREE, NULL_TREE);
1092 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
1094 emit_stack_save (SAVE_NONLOCAL, &r_save, NULL_RTX);
1097 /* Return an rtx representing the address of an area of memory dynamically
1098 pushed on the stack. This region of memory is always aligned to
1099 a multiple of BIGGEST_ALIGNMENT.
1101 Any required stack pointer alignment is preserved.
1103 SIZE is an rtx representing the size of the area.
1104 TARGET is a place in which the address can be placed.
1106 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1109 allocate_dynamic_stack_space (rtx size, rtx target, int known_align)
1111 /* If we're asking for zero bytes, it doesn't matter what we point
1112 to since we can't dereference it. But return a reasonable
1114 if (size == const0_rtx)
1115 return virtual_stack_dynamic_rtx;
1117 /* Otherwise, show we're calling alloca or equivalent. */
1118 cfun->calls_alloca = 1;
1120 /* Ensure the size is in the proper mode. */
1121 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1122 size = convert_to_mode (Pmode, size, 1);
1124 /* We can't attempt to minimize alignment necessary, because we don't
1125 know the final value of preferred_stack_boundary yet while executing
1127 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1129 /* We will need to ensure that the address we return is aligned to
1130 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1131 always know its final value at this point in the compilation (it
1132 might depend on the size of the outgoing parameter lists, for
1133 example), so we must align the value to be returned in that case.
1134 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1135 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1136 We must also do an alignment operation on the returned value if
1137 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1139 If we have to align, we must leave space in SIZE for the hole
1140 that might result from the alignment operation. */
1142 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1143 #define MUST_ALIGN 1
1145 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1150 = force_operand (plus_constant (size,
1151 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1154 #ifdef SETJMP_VIA_SAVE_AREA
1155 /* If setjmp restores regs from a save area in the stack frame,
1156 avoid clobbering the reg save area. Note that the offset of
1157 virtual_incoming_args_rtx includes the preallocated stack args space.
1158 It would be no problem to clobber that, but it's on the wrong side
1159 of the old save area.
1161 What used to happen is that, since we did not know for sure
1162 whether setjmp() was invoked until after RTL generation, we
1163 would use reg notes to store the "optimized" size and fix things
1164 up later. These days we know this information before we ever
1165 start building RTL so the reg notes are unnecessary. */
1166 if (!cfun->calls_setjmp)
1168 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1170 /* ??? Code below assumes that the save area needs maximal
1171 alignment. This constraint may be too strong. */
1172 gcc_assert (PREFERRED_STACK_BOUNDARY == BIGGEST_ALIGNMENT);
1174 if (CONST_INT_P (size))
1176 HOST_WIDE_INT new_size = INTVAL (size) / align * align;
1178 if (INTVAL (size) != new_size)
1179 size = GEN_INT (new_size);
1183 /* Since we know overflow is not possible, we avoid using
1184 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1185 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1186 GEN_INT (align), NULL_RTX, 1);
1187 size = expand_mult (Pmode, size,
1188 GEN_INT (align), NULL_RTX, 1);
1194 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1195 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1197 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1198 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1200 #endif /* SETJMP_VIA_SAVE_AREA */
1202 /* Round the size to a multiple of the required stack alignment.
1203 Since the stack if presumed to be rounded before this allocation,
1204 this will maintain the required alignment.
1206 If the stack grows downward, we could save an insn by subtracting
1207 SIZE from the stack pointer and then aligning the stack pointer.
1208 The problem with this is that the stack pointer may be unaligned
1209 between the execution of the subtraction and alignment insns and
1210 some machines do not allow this. Even on those that do, some
1211 signal handlers malfunction if a signal should occur between those
1212 insns. Since this is an extremely rare event, we have no reliable
1213 way of knowing which systems have this problem. So we avoid even
1214 momentarily mis-aligning the stack. */
1216 /* If we added a variable amount to SIZE,
1217 we can no longer assume it is aligned. */
1218 #if !defined (SETJMP_VIA_SAVE_AREA)
1219 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1221 size = round_push (size);
1223 do_pending_stack_adjust ();
1225 /* We ought to be called always on the toplevel and stack ought to be aligned
1227 gcc_assert (!(stack_pointer_delta
1228 % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)));
1230 /* If needed, check that we have the required amount of stack.
1231 Take into account what has already been checked. */
1232 if (flag_stack_check == GENERIC_STACK_CHECK)
1233 probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE,
1235 else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK)
1236 probe_stack_range (STACK_CHECK_PROTECT, size);
1238 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1239 if (target == 0 || !REG_P (target)
1240 || REGNO (target) < FIRST_PSEUDO_REGISTER
1241 || GET_MODE (target) != Pmode)
1242 target = gen_reg_rtx (Pmode);
1244 mark_reg_pointer (target, known_align);
1246 /* Perform the required allocation from the stack. Some systems do
1247 this differently than simply incrementing/decrementing from the
1248 stack pointer, such as acquiring the space by calling malloc(). */
1249 #ifdef HAVE_allocate_stack
1250 if (HAVE_allocate_stack)
1252 enum machine_mode mode = STACK_SIZE_MODE;
1253 insn_operand_predicate_fn pred;
1255 /* We don't have to check against the predicate for operand 0 since
1256 TARGET is known to be a pseudo of the proper mode, which must
1257 be valid for the operand. For operand 1, convert to the
1258 proper mode and validate. */
1259 if (mode == VOIDmode)
1260 mode = insn_data[(int) CODE_FOR_allocate_stack].operand[1].mode;
1262 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1263 if (pred && ! ((*pred) (size, mode)))
1264 size = copy_to_mode_reg (mode, convert_to_mode (mode, size, 1));
1266 emit_insn (gen_allocate_stack (target, size));
1271 #ifndef STACK_GROWS_DOWNWARD
1272 emit_move_insn (target, virtual_stack_dynamic_rtx);
1275 /* Check stack bounds if necessary. */
1276 if (crtl->limit_stack)
1279 rtx space_available = gen_label_rtx ();
1280 #ifdef STACK_GROWS_DOWNWARD
1281 available = expand_binop (Pmode, sub_optab,
1282 stack_pointer_rtx, stack_limit_rtx,
1283 NULL_RTX, 1, OPTAB_WIDEN);
1285 available = expand_binop (Pmode, sub_optab,
1286 stack_limit_rtx, stack_pointer_rtx,
1287 NULL_RTX, 1, OPTAB_WIDEN);
1289 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1293 emit_insn (gen_trap ());
1296 error ("stack limits not supported on this target");
1298 emit_label (space_available);
1301 anti_adjust_stack (size);
1303 #ifdef STACK_GROWS_DOWNWARD
1304 emit_move_insn (target, virtual_stack_dynamic_rtx);
1310 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1311 but we know it can't. So add ourselves and then do
1313 target = expand_binop (Pmode, add_optab, target,
1314 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1315 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1316 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1317 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1319 target = expand_mult (Pmode, target,
1320 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1324 /* Record the new stack level for nonlocal gotos. */
1325 if (cfun->nonlocal_goto_save_area != 0)
1326 update_nonlocal_goto_save_area ();
1331 /* A front end may want to override GCC's stack checking by providing a
1332 run-time routine to call to check the stack, so provide a mechanism for
1333 calling that routine. */
1335 static GTY(()) rtx stack_check_libfunc;
1338 set_stack_check_libfunc (rtx libfunc)
1340 stack_check_libfunc = libfunc;
1343 /* Emit one stack probe at ADDRESS, an address within the stack. */
1346 emit_stack_probe (rtx address)
1348 rtx memref = gen_rtx_MEM (word_mode, address);
1350 MEM_VOLATILE_P (memref) = 1;
1352 if (STACK_CHECK_PROBE_LOAD)
1353 emit_move_insn (gen_reg_rtx (word_mode), memref);
1355 emit_move_insn (memref, const0_rtx);
1358 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1359 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1360 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1361 subtract from the stack. If SIZE is constant, this is done
1362 with a fixed number of probes. Otherwise, we must make a loop. */
1364 #ifdef STACK_GROWS_DOWNWARD
1365 #define STACK_GROW_OP MINUS
1367 #define STACK_GROW_OP PLUS
1371 probe_stack_range (HOST_WIDE_INT first, rtx size)
1373 /* First ensure SIZE is Pmode. */
1374 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1375 size = convert_to_mode (Pmode, size, 1);
1377 /* Next see if the front end has set up a function for us to call to
1379 if (stack_check_libfunc != 0)
1381 rtx addr = memory_address (QImode,
1382 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1384 plus_constant (size, first)));
1386 addr = convert_memory_address (ptr_mode, addr);
1387 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1391 /* Next see if we have an insn to check the stack. Use it if so. */
1392 #ifdef HAVE_check_stack
1393 else if (HAVE_check_stack)
1395 insn_operand_predicate_fn pred;
1397 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1399 plus_constant (size, first)),
1402 pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1403 if (pred && ! ((*pred) (last_addr, Pmode)))
1404 last_addr = copy_to_mode_reg (Pmode, last_addr);
1406 emit_insn (gen_check_stack (last_addr));
1410 /* If we have to generate explicit probes, see if we have a constant
1411 small number of them to generate. If so, that's the easy case. */
1412 else if (CONST_INT_P (size)
1413 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1415 HOST_WIDE_INT offset;
1417 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1418 for values of N from 1 until it exceeds LAST. If only one
1419 probe is needed, this will not generate any code. Then probe
1421 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1422 offset < INTVAL (size);
1423 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1424 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1428 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1430 plus_constant (size, first)));
1433 /* In the variable case, do the same as above, but in a loop. We emit loop
1434 notes so that loop optimization can be done. */
1438 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1440 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1443 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1445 plus_constant (size, first)),
1447 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1448 rtx loop_lab = gen_label_rtx ();
1449 rtx test_lab = gen_label_rtx ();
1450 rtx end_lab = gen_label_rtx ();
1453 if (!REG_P (test_addr)
1454 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1455 test_addr = force_reg (Pmode, test_addr);
1457 emit_jump (test_lab);
1459 emit_label (loop_lab);
1460 emit_stack_probe (test_addr);
1462 #ifdef STACK_GROWS_DOWNWARD
1463 #define CMP_OPCODE GTU
1464 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1467 #define CMP_OPCODE LTU
1468 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1472 gcc_assert (temp == test_addr);
1474 emit_label (test_lab);
1475 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1476 NULL_RTX, Pmode, 1, loop_lab);
1477 emit_jump (end_lab);
1478 emit_label (end_lab);
1480 emit_stack_probe (last_addr);
1484 /* Return an rtx representing the register or memory location
1485 in which a scalar value of data type VALTYPE
1486 was returned by a function call to function FUNC.
1487 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
1488 function is known, otherwise 0.
1489 OUTGOING is 1 if on a machine with register windows this function
1490 should return the register in which the function will put its result
1494 hard_function_value (const_tree valtype, const_tree func, const_tree fntype,
1495 int outgoing ATTRIBUTE_UNUSED)
1499 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing);
1502 && GET_MODE (val) == BLKmode)
1504 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1505 enum machine_mode tmpmode;
1507 /* int_size_in_bytes can return -1. We don't need a check here
1508 since the value of bytes will then be large enough that no
1509 mode will match anyway. */
1511 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1512 tmpmode != VOIDmode;
1513 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1515 /* Have we found a large enough mode? */
1516 if (GET_MODE_SIZE (tmpmode) >= bytes)
1520 /* No suitable mode found. */
1521 gcc_assert (tmpmode != VOIDmode);
1523 PUT_MODE (val, tmpmode);
1528 /* Return an rtx representing the register or memory location
1529 in which a scalar value of mode MODE was returned by a library call. */
1532 hard_libcall_value (enum machine_mode mode)
1534 return LIBCALL_VALUE (mode);
1537 /* Look up the tree code for a given rtx code
1538 to provide the arithmetic operation for REAL_ARITHMETIC.
1539 The function returns an int because the caller may not know
1540 what `enum tree_code' means. */
1543 rtx_to_tree_code (enum rtx_code code)
1545 enum tree_code tcode;
1568 tcode = LAST_AND_UNUSED_TREE_CODE;
1571 return ((int) tcode);
1574 #include "gt-explow.h"