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 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
25 #include "coretypes.h"
35 #include "hard-reg-set.h"
36 #include "insn-config.h"
39 #include "langhooks.h"
41 static rtx break_out_memory_refs PARAMS ((rtx));
42 static void emit_stack_probe PARAMS ((rtx));
45 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
48 trunc_int_for_mode (c, mode)
50 enum machine_mode mode;
52 int width = GET_MODE_BITSIZE (mode);
54 /* You want to truncate to a _what_? */
55 if (! 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.
78 This function should be used via the `plus_constant' macro. */
81 plus_constant_wide (x, c)
87 enum machine_mode mode;
103 return GEN_INT (INTVAL (x) + c);
107 unsigned HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
108 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
109 unsigned HOST_WIDE_INT l2 = c;
110 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
111 unsigned HOST_WIDE_INT lv;
114 add_double (l1, h1, l2, h2, &lv, &hv);
116 return immed_double_const (lv, hv, VOIDmode);
120 /* If this is a reference to the constant pool, try replacing it with
121 a reference to a new constant. If the resulting address isn't
122 valid, don't return it because we have no way to validize it. */
123 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
124 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
127 = force_const_mem (GET_MODE (x),
128 plus_constant (get_pool_constant (XEXP (x, 0)),
130 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
136 /* If adding to something entirely constant, set a flag
137 so that we can add a CONST around the result. */
148 /* The interesting case is adding the integer to a sum.
149 Look for constant term in the sum and combine
150 with C. For an integer constant term, we make a combined
151 integer. For a constant term that is not an explicit integer,
152 we cannot really combine, but group them together anyway.
154 Restart or use a recursive call in case the remaining operand is
155 something that we handle specially, such as a SYMBOL_REF.
157 We may not immediately return from the recursive call here, lest
158 all_constant gets lost. */
160 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
162 c += INTVAL (XEXP (x, 1));
164 if (GET_MODE (x) != VOIDmode)
165 c = trunc_int_for_mode (c, GET_MODE (x));
170 else if (CONSTANT_P (XEXP (x, 1)))
172 x = gen_rtx_PLUS (mode, XEXP (x, 0), plus_constant (XEXP (x, 1), c));
175 else if (find_constant_term_loc (&y))
177 /* We need to be careful since X may be shared and we can't
178 modify it in place. */
179 rtx copy = copy_rtx (x);
180 rtx *const_loc = find_constant_term_loc (©);
182 *const_loc = plus_constant (*const_loc, c);
193 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
195 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
197 else if (all_constant)
198 return gen_rtx_CONST (mode, x);
203 /* If X is a sum, return a new sum like X but lacking any constant terms.
204 Add all the removed constant terms into *CONSTPTR.
205 X itself is not altered. The result != X if and only if
206 it is not isomorphic to X. */
209 eliminate_constant_term (x, constptr)
216 if (GET_CODE (x) != PLUS)
219 /* First handle constants appearing at this level explicitly. */
220 if (GET_CODE (XEXP (x, 1)) == CONST_INT
221 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
223 && GET_CODE (tem) == CONST_INT)
226 return eliminate_constant_term (XEXP (x, 0), constptr);
230 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
231 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
232 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
233 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
235 && GET_CODE (tem) == CONST_INT)
238 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
244 /* Returns the insn that next references REG after INSN, or 0
245 if REG is clobbered before next referenced or we cannot find
246 an insn that references REG in a straight-line piece of code. */
249 find_next_ref (reg, insn)
255 for (insn = NEXT_INSN (insn); insn; insn = next)
257 next = NEXT_INSN (insn);
258 if (GET_CODE (insn) == NOTE)
260 if (GET_CODE (insn) == CODE_LABEL
261 || GET_CODE (insn) == BARRIER)
263 if (GET_CODE (insn) == INSN
264 || GET_CODE (insn) == JUMP_INSN
265 || GET_CODE (insn) == CALL_INSN)
267 if (reg_set_p (reg, insn))
269 if (reg_mentioned_p (reg, PATTERN (insn)))
271 if (GET_CODE (insn) == JUMP_INSN)
273 if (any_uncondjump_p (insn))
274 next = JUMP_LABEL (insn);
278 if (GET_CODE (insn) == CALL_INSN
279 && REGNO (reg) < FIRST_PSEUDO_REGISTER
280 && call_used_regs[REGNO (reg)])
289 /* Return an rtx for the size in bytes of the value of EXP. */
295 tree size = (*lang_hooks.expr_size) (exp);
297 if (TREE_CODE (size) != INTEGER_CST
298 && contains_placeholder_p (size))
299 size = build (WITH_RECORD_EXPR, sizetype, size, exp);
301 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), 0);
304 /* Return a wide integer for the size in bytes of the value of EXP, or -1
305 if the size can vary or is larger than an integer. */
311 tree t = (*lang_hooks.expr_size) (exp);
314 || TREE_CODE (t) != INTEGER_CST
316 || TREE_INT_CST_HIGH (t) != 0
317 /* If the result would appear negative, it's too big to represent. */
318 || (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0)
321 return TREE_INT_CST_LOW (t);
324 /* Return a copy of X in which all memory references
325 and all constants that involve symbol refs
326 have been replaced with new temporary registers.
327 Also emit code to load the memory locations and constants
328 into those registers.
330 If X contains no such constants or memory references,
331 X itself (not a copy) is returned.
333 If a constant is found in the address that is not a legitimate constant
334 in an insn, it is left alone in the hope that it might be valid in the
337 X may contain no arithmetic except addition, subtraction and multiplication.
338 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
341 break_out_memory_refs (x)
344 if (GET_CODE (x) == MEM
345 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
346 && GET_MODE (x) != VOIDmode))
347 x = force_reg (GET_MODE (x), x);
348 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
349 || GET_CODE (x) == MULT)
351 rtx op0 = break_out_memory_refs (XEXP (x, 0));
352 rtx op1 = break_out_memory_refs (XEXP (x, 1));
354 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
355 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
361 #ifdef POINTERS_EXTEND_UNSIGNED
363 /* Given X, a memory address in ptr_mode, convert it to an address
364 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
365 the fact that pointers are not allowed to overflow by commuting arithmetic
366 operations over conversions so that address arithmetic insns can be
370 convert_memory_address (to_mode, x)
371 enum machine_mode to_mode;
374 enum machine_mode from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
378 /* Here we handle some special cases. If none of them apply, fall through
379 to the default case. */
380 switch (GET_CODE (x))
384 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
386 else if (POINTERS_EXTEND_UNSIGNED < 0)
388 else if (POINTERS_EXTEND_UNSIGNED > 0)
392 temp = simplify_unary_operation (code, to_mode, x, from_mode);
398 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
399 && GET_MODE (SUBREG_REG (x)) == to_mode)
400 return SUBREG_REG (x);
404 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
405 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
410 temp = shallow_copy_rtx (x);
411 PUT_MODE (temp, to_mode);
416 return gen_rtx_CONST (to_mode,
417 convert_memory_address (to_mode, XEXP (x, 0)));
422 /* For addition we can safely permute the conversion and addition
423 operation if one operand is a constant and converting the constant
424 does not change it. We can always safely permute them if we are
425 making the address narrower. */
426 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
427 || (GET_CODE (x) == PLUS
428 && GET_CODE (XEXP (x, 1)) == CONST_INT
429 && XEXP (x, 1) == convert_memory_address (to_mode, XEXP (x, 1))))
430 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
431 convert_memory_address (to_mode, XEXP (x, 0)),
439 return convert_modes (to_mode, from_mode,
440 x, POINTERS_EXTEND_UNSIGNED);
444 /* Given a memory address or facsimile X, construct a new address,
445 currently equivalent, that is stable: future stores won't change it.
447 X must be composed of constants, register and memory references
448 combined with addition, subtraction and multiplication:
449 in other words, just what you can get from expand_expr if sum_ok is 1.
451 Works by making copies of all regs and memory locations used
452 by X and combining them the same way X does.
453 You could also stabilize the reference to this address
454 by copying the address to a register with copy_to_reg;
455 but then you wouldn't get indexed addressing in the reference. */
461 if (GET_CODE (x) == REG)
463 if (REGNO (x) != FRAME_POINTER_REGNUM
464 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
465 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
470 else if (GET_CODE (x) == MEM)
472 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
473 || GET_CODE (x) == MULT)
475 rtx op0 = copy_all_regs (XEXP (x, 0));
476 rtx op1 = copy_all_regs (XEXP (x, 1));
477 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
478 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
483 /* Return something equivalent to X but valid as a memory address
484 for something of mode MODE. When X is not itself valid, this
485 works by copying X or subexpressions of it into registers. */
488 memory_address (mode, x)
489 enum machine_mode mode;
494 if (GET_CODE (x) == ADDRESSOF)
497 #ifdef POINTERS_EXTEND_UNSIGNED
498 if (GET_MODE (x) != Pmode)
499 x = convert_memory_address (Pmode, x);
502 /* By passing constant addresses thru registers
503 we get a chance to cse them. */
504 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
505 x = force_reg (Pmode, x);
507 /* Accept a QUEUED that refers to a REG
508 even though that isn't a valid address.
509 On attempting to put this in an insn we will call protect_from_queue
510 which will turn it into a REG, which is valid. */
511 else if (GET_CODE (x) == QUEUED
512 && GET_CODE (QUEUED_VAR (x)) == REG)
515 /* We get better cse by rejecting indirect addressing at this stage.
516 Let the combiner create indirect addresses where appropriate.
517 For now, generate the code so that the subexpressions useful to share
518 are visible. But not if cse won't be done! */
521 if (! cse_not_expected && GET_CODE (x) != REG)
522 x = break_out_memory_refs (x);
524 /* At this point, any valid address is accepted. */
525 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
527 /* If it was valid before but breaking out memory refs invalidated it,
528 use it the old way. */
529 if (memory_address_p (mode, oldx))
532 /* Perform machine-dependent transformations on X
533 in certain cases. This is not necessary since the code
534 below can handle all possible cases, but machine-dependent
535 transformations can make better code. */
536 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
538 /* PLUS and MULT can appear in special ways
539 as the result of attempts to make an address usable for indexing.
540 Usually they are dealt with by calling force_operand, below.
541 But a sum containing constant terms is special
542 if removing them makes the sum a valid address:
543 then we generate that address in a register
544 and index off of it. We do this because it often makes
545 shorter code, and because the addresses thus generated
546 in registers often become common subexpressions. */
547 if (GET_CODE (x) == PLUS)
549 rtx constant_term = const0_rtx;
550 rtx y = eliminate_constant_term (x, &constant_term);
551 if (constant_term == const0_rtx
552 || ! memory_address_p (mode, y))
553 x = force_operand (x, NULL_RTX);
556 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
557 if (! memory_address_p (mode, y))
558 x = force_operand (x, NULL_RTX);
564 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
565 x = force_operand (x, NULL_RTX);
567 /* If we have a register that's an invalid address,
568 it must be a hard reg of the wrong class. Copy it to a pseudo. */
569 else if (GET_CODE (x) == REG)
572 /* Last resort: copy the value to a register, since
573 the register is a valid address. */
575 x = force_reg (Pmode, x);
582 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG
583 /* Don't copy an addr via a reg if it is one of our stack slots. */
584 && ! (GET_CODE (x) == PLUS
585 && (XEXP (x, 0) == virtual_stack_vars_rtx
586 || XEXP (x, 0) == virtual_incoming_args_rtx)))
588 if (general_operand (x, Pmode))
589 x = force_reg (Pmode, x);
591 x = force_operand (x, NULL_RTX);
597 /* If we didn't change the address, we are done. Otherwise, mark
598 a reg as a pointer if we have REG or REG + CONST_INT. */
601 else if (GET_CODE (x) == REG)
602 mark_reg_pointer (x, BITS_PER_UNIT);
603 else if (GET_CODE (x) == PLUS
604 && GET_CODE (XEXP (x, 0)) == REG
605 && GET_CODE (XEXP (x, 1)) == CONST_INT)
606 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
608 /* OLDX may have been the address on a temporary. Update the address
609 to indicate that X is now used. */
610 update_temp_slot_address (oldx, x);
615 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
618 memory_address_noforce (mode, x)
619 enum machine_mode mode;
622 int ambient_force_addr = flag_force_addr;
626 val = memory_address (mode, x);
627 flag_force_addr = ambient_force_addr;
631 /* Convert a mem ref into one with a valid memory address.
632 Pass through anything else unchanged. */
638 if (GET_CODE (ref) != MEM)
640 if (! (flag_force_addr && CONSTANT_ADDRESS_P (XEXP (ref, 0)))
641 && memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
644 /* Don't alter REF itself, since that is probably a stack slot. */
645 return replace_equiv_address (ref, XEXP (ref, 0));
648 /* Given REF, either a MEM or a REG, and T, either the type of X or
649 the expression corresponding to REF, set RTX_UNCHANGING_P if
653 maybe_set_unchanging (ref, t)
657 /* We can set RTX_UNCHANGING_P from TREE_READONLY for decls whose
658 initialization is only executed once, or whose initializer always
659 has the same value. Currently we simplify this to PARM_DECLs in the
660 first case, and decls with TREE_CONSTANT initializers in the second.
662 We cannot do this for non-static aggregates, because of the double
663 writes that can be generated by store_constructor, depending on the
664 contents of the initializer. Yes, this does eliminate a good fraction
665 of the number of uses of RTX_UNCHANGING_P for a language like Ada.
666 It also eliminates a good quantity of bugs. Let this be incentive to
667 eliminate RTX_UNCHANGING_P entirely in favour of a more reliable
668 solution, perhaps based on alias sets. */
670 if ((TREE_READONLY (t) && DECL_P (t)
671 && (TREE_STATIC (t) || ! AGGREGATE_TYPE_P (TREE_TYPE (t)))
672 && (TREE_CODE (t) == PARM_DECL
673 || (DECL_INITIAL (t) && TREE_CONSTANT (DECL_INITIAL (t)))))
674 || TREE_CODE_CLASS (TREE_CODE (t)) == 'c')
675 RTX_UNCHANGING_P (ref) = 1;
678 /* Return a modified copy of X with its memory address copied
679 into a temporary register to protect it from side effects.
680 If X is not a MEM, it is returned unchanged (and not copied).
681 Perhaps even if it is a MEM, if there is no need to change it. */
687 if (GET_CODE (x) != MEM
688 || ! rtx_unstable_p (XEXP (x, 0)))
692 replace_equiv_address (x, force_reg (Pmode, copy_all_regs (XEXP (x, 0))));
695 /* Copy the value or contents of X to a new temp reg and return that reg. */
701 rtx temp = gen_reg_rtx (GET_MODE (x));
703 /* If not an operand, must be an address with PLUS and MULT so
704 do the computation. */
705 if (! general_operand (x, VOIDmode))
706 x = force_operand (x, temp);
709 emit_move_insn (temp, x);
714 /* Like copy_to_reg but always give the new register mode Pmode
715 in case X is a constant. */
721 return copy_to_mode_reg (Pmode, x);
724 /* Like copy_to_reg but always give the new register mode MODE
725 in case X is a constant. */
728 copy_to_mode_reg (mode, x)
729 enum machine_mode mode;
732 rtx temp = gen_reg_rtx (mode);
734 /* If not an operand, must be an address with PLUS and MULT so
735 do the computation. */
736 if (! general_operand (x, VOIDmode))
737 x = force_operand (x, temp);
739 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
742 emit_move_insn (temp, x);
746 /* Load X into a register if it is not already one.
747 Use mode MODE for the register.
748 X should be valid for mode MODE, but it may be a constant which
749 is valid for all integer modes; that's why caller must specify MODE.
751 The caller must not alter the value in the register we return,
752 since we mark it as a "constant" register. */
756 enum machine_mode mode;
761 if (GET_CODE (x) == REG)
764 if (general_operand (x, mode))
766 temp = gen_reg_rtx (mode);
767 insn = emit_move_insn (temp, x);
771 temp = force_operand (x, NULL_RTX);
772 if (GET_CODE (temp) == REG)
773 insn = get_last_insn ();
776 rtx temp2 = gen_reg_rtx (mode);
777 insn = emit_move_insn (temp2, temp);
782 /* Let optimizers know that TEMP's value never changes
783 and that X can be substituted for it. Don't get confused
784 if INSN set something else (such as a SUBREG of TEMP). */
786 && (set = single_set (insn)) != 0
787 && SET_DEST (set) == temp
788 && ! rtx_equal_p (x, SET_SRC (set)))
789 set_unique_reg_note (insn, REG_EQUAL, x);
794 /* If X is a memory ref, copy its contents to a new temp reg and return
795 that reg. Otherwise, return X. */
803 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode)
806 temp = gen_reg_rtx (GET_MODE (x));
807 emit_move_insn (temp, x);
811 /* Copy X to TARGET (if it's nonzero and a reg)
812 or to a new temp reg and return that reg.
813 MODE is the mode to use for X in case it is a constant. */
816 copy_to_suggested_reg (x, target, mode)
818 enum machine_mode mode;
822 if (target && GET_CODE (target) == REG)
825 temp = gen_reg_rtx (mode);
827 emit_move_insn (temp, x);
831 /* Return the mode to use to store a scalar of TYPE and MODE.
832 PUNSIGNEDP points to the signedness of the type and may be adjusted
833 to show what signedness to use on extension operations.
835 FOR_CALL is nonzero if this call is promoting args for a call. */
838 promote_mode (type, mode, punsignedp, for_call)
840 enum machine_mode mode;
842 int for_call ATTRIBUTE_UNUSED;
844 enum tree_code code = TREE_CODE (type);
845 int unsignedp = *punsignedp;
847 #ifdef PROMOTE_FOR_CALL_ONLY
855 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
856 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
857 PROMOTE_MODE (mode, unsignedp, type);
861 #ifdef POINTERS_EXTEND_UNSIGNED
865 unsignedp = POINTERS_EXTEND_UNSIGNED;
873 *punsignedp = unsignedp;
877 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
878 This pops when ADJUST is positive. ADJUST need not be constant. */
881 adjust_stack (adjust)
885 adjust = protect_from_queue (adjust, 0);
887 if (adjust == const0_rtx)
890 /* We expect all variable sized adjustments to be multiple of
891 PREFERRED_STACK_BOUNDARY. */
892 if (GET_CODE (adjust) == CONST_INT)
893 stack_pointer_delta -= INTVAL (adjust);
895 temp = expand_binop (Pmode,
896 #ifdef STACK_GROWS_DOWNWARD
901 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
904 if (temp != stack_pointer_rtx)
905 emit_move_insn (stack_pointer_rtx, temp);
908 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
909 This pushes when ADJUST is positive. ADJUST need not be constant. */
912 anti_adjust_stack (adjust)
916 adjust = protect_from_queue (adjust, 0);
918 if (adjust == const0_rtx)
921 /* We expect all variable sized adjustments to be multiple of
922 PREFERRED_STACK_BOUNDARY. */
923 if (GET_CODE (adjust) == CONST_INT)
924 stack_pointer_delta += INTVAL (adjust);
926 temp = expand_binop (Pmode,
927 #ifdef STACK_GROWS_DOWNWARD
932 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
935 if (temp != stack_pointer_rtx)
936 emit_move_insn (stack_pointer_rtx, temp);
939 /* Round the size of a block to be pushed up to the boundary required
940 by this machine. SIZE is the desired size, which need not be constant. */
946 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
951 if (GET_CODE (size) == CONST_INT)
953 HOST_WIDE_INT new = (INTVAL (size) + align - 1) / align * align;
955 if (INTVAL (size) != new)
956 size = GEN_INT (new);
960 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
961 but we know it can't. So add ourselves and then do
963 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
964 NULL_RTX, 1, OPTAB_LIB_WIDEN);
965 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
967 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
973 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
974 to a previously-created save area. If no save area has been allocated,
975 this function will allocate one. If a save area is specified, it
976 must be of the proper mode.
978 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
979 are emitted at the current position. */
982 emit_stack_save (save_level, psave, after)
983 enum save_level save_level;
988 /* The default is that we use a move insn and save in a Pmode object. */
989 rtx (*fcn) PARAMS ((rtx, rtx)) = gen_move_insn;
990 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
992 /* See if this machine has anything special to do for this kind of save. */
995 #ifdef HAVE_save_stack_block
997 if (HAVE_save_stack_block)
998 fcn = gen_save_stack_block;
1001 #ifdef HAVE_save_stack_function
1003 if (HAVE_save_stack_function)
1004 fcn = gen_save_stack_function;
1007 #ifdef HAVE_save_stack_nonlocal
1009 if (HAVE_save_stack_nonlocal)
1010 fcn = gen_save_stack_nonlocal;
1017 /* If there is no save area and we have to allocate one, do so. Otherwise
1018 verify the save area is the proper mode. */
1022 if (mode != VOIDmode)
1024 if (save_level == SAVE_NONLOCAL)
1025 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
1027 *psave = sa = gen_reg_rtx (mode);
1032 if (mode == VOIDmode || GET_MODE (sa) != mode)
1041 /* We must validize inside the sequence, to ensure that any instructions
1042 created by the validize call also get moved to the right place. */
1044 sa = validize_mem (sa);
1045 emit_insn (fcn (sa, stack_pointer_rtx));
1048 emit_insn_after (seq, after);
1053 sa = validize_mem (sa);
1054 emit_insn (fcn (sa, stack_pointer_rtx));
1058 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1059 area made by emit_stack_save. If it is zero, we have nothing to do.
1061 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1062 current position. */
1065 emit_stack_restore (save_level, sa, after)
1066 enum save_level save_level;
1070 /* The default is that we use a move insn. */
1071 rtx (*fcn) PARAMS ((rtx, rtx)) = gen_move_insn;
1073 /* See if this machine has anything special to do for this kind of save. */
1076 #ifdef HAVE_restore_stack_block
1078 if (HAVE_restore_stack_block)
1079 fcn = gen_restore_stack_block;
1082 #ifdef HAVE_restore_stack_function
1084 if (HAVE_restore_stack_function)
1085 fcn = gen_restore_stack_function;
1088 #ifdef HAVE_restore_stack_nonlocal
1090 if (HAVE_restore_stack_nonlocal)
1091 fcn = gen_restore_stack_nonlocal;
1100 sa = validize_mem (sa);
1101 /* These clobbers prevent the scheduler from moving
1102 references to variable arrays below the code
1103 that deletes (pops) the arrays. */
1104 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1105 gen_rtx_MEM (BLKmode,
1106 gen_rtx_SCRATCH (VOIDmode))));
1107 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1108 gen_rtx_MEM (BLKmode, stack_pointer_rtx)));
1116 emit_insn (fcn (stack_pointer_rtx, sa));
1119 emit_insn_after (seq, after);
1122 emit_insn (fcn (stack_pointer_rtx, sa));
1125 #ifdef SETJMP_VIA_SAVE_AREA
1126 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1127 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1128 platforms, the dynamic stack space used can corrupt the original
1129 frame, thus causing a crash if a longjmp unwinds to it. */
1132 optimize_save_area_alloca (insns)
1137 for (insn = insns; insn; insn = NEXT_INSN(insn))
1141 if (GET_CODE (insn) != INSN)
1144 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1146 if (REG_NOTE_KIND (note) != REG_SAVE_AREA)
1149 if (!current_function_calls_setjmp)
1151 rtx pat = PATTERN (insn);
1153 /* If we do not see the note in a pattern matching
1154 these precise characteristics, we did something
1155 entirely wrong in allocate_dynamic_stack_space.
1157 Note, one way this could happen is if SETJMP_VIA_SAVE_AREA
1158 was defined on a machine where stacks grow towards higher
1161 Right now only supported port with stack that grow upward
1162 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1163 if (GET_CODE (pat) != SET
1164 || SET_DEST (pat) != stack_pointer_rtx
1165 || GET_CODE (SET_SRC (pat)) != MINUS
1166 || XEXP (SET_SRC (pat), 0) != stack_pointer_rtx)
1169 /* This will now be transformed into a (set REG REG)
1170 so we can just blow away all the other notes. */
1171 XEXP (SET_SRC (pat), 1) = XEXP (note, 0);
1172 REG_NOTES (insn) = NULL_RTX;
1176 /* setjmp was called, we must remove the REG_SAVE_AREA
1177 note so that later passes do not get confused by its
1179 if (note == REG_NOTES (insn))
1181 REG_NOTES (insn) = XEXP (note, 1);
1187 for (srch = REG_NOTES (insn); srch; srch = XEXP (srch, 1))
1188 if (XEXP (srch, 1) == note)
1191 if (srch == NULL_RTX)
1194 XEXP (srch, 1) = XEXP (note, 1);
1197 /* Once we've seen the note of interest, we need not look at
1198 the rest of them. */
1203 #endif /* SETJMP_VIA_SAVE_AREA */
1205 /* Return an rtx representing the address of an area of memory dynamically
1206 pushed on the stack. This region of memory is always aligned to
1207 a multiple of BIGGEST_ALIGNMENT.
1209 Any required stack pointer alignment is preserved.
1211 SIZE is an rtx representing the size of the area.
1212 TARGET is a place in which the address can be placed.
1214 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1217 allocate_dynamic_stack_space (size, target, known_align)
1222 #ifdef SETJMP_VIA_SAVE_AREA
1223 rtx setjmpless_size = NULL_RTX;
1226 /* If we're asking for zero bytes, it doesn't matter what we point
1227 to since we can't dereference it. But return a reasonable
1229 if (size == const0_rtx)
1230 return virtual_stack_dynamic_rtx;
1232 /* Otherwise, show we're calling alloca or equivalent. */
1233 current_function_calls_alloca = 1;
1235 /* Ensure the size is in the proper mode. */
1236 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1237 size = convert_to_mode (Pmode, size, 1);
1239 /* We can't attempt to minimize alignment necessary, because we don't
1240 know the final value of preferred_stack_boundary yet while executing
1242 cfun->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1244 /* We will need to ensure that the address we return is aligned to
1245 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1246 always know its final value at this point in the compilation (it
1247 might depend on the size of the outgoing parameter lists, for
1248 example), so we must align the value to be returned in that case.
1249 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1250 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1251 We must also do an alignment operation on the returned value if
1252 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1254 If we have to align, we must leave space in SIZE for the hole
1255 that might result from the alignment operation. */
1257 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1258 #define MUST_ALIGN 1
1260 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1265 = force_operand (plus_constant (size,
1266 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1269 #ifdef SETJMP_VIA_SAVE_AREA
1270 /* If setjmp restores regs from a save area in the stack frame,
1271 avoid clobbering the reg save area. Note that the offset of
1272 virtual_incoming_args_rtx includes the preallocated stack args space.
1273 It would be no problem to clobber that, but it's on the wrong side
1274 of the old save area. */
1277 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1278 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1280 if (!current_function_calls_setjmp)
1282 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1284 /* See optimize_save_area_alloca to understand what is being
1287 /* ??? Code below assumes that the save area needs maximal
1288 alignment. This constraint may be too strong. */
1289 if (PREFERRED_STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1292 if (GET_CODE (size) == CONST_INT)
1294 HOST_WIDE_INT new = INTVAL (size) / align * align;
1296 if (INTVAL (size) != new)
1297 setjmpless_size = GEN_INT (new);
1299 setjmpless_size = size;
1303 /* Since we know overflow is not possible, we avoid using
1304 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1305 setjmpless_size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1306 GEN_INT (align), NULL_RTX, 1);
1307 setjmpless_size = expand_mult (Pmode, setjmpless_size,
1308 GEN_INT (align), NULL_RTX, 1);
1310 /* Our optimization works based upon being able to perform a simple
1311 transformation of this RTL into a (set REG REG) so make sure things
1312 did in fact end up in a REG. */
1313 if (!register_operand (setjmpless_size, Pmode))
1314 setjmpless_size = force_reg (Pmode, setjmpless_size);
1317 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1318 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1320 #endif /* SETJMP_VIA_SAVE_AREA */
1322 /* Round the size to a multiple of the required stack alignment.
1323 Since the stack if presumed to be rounded before this allocation,
1324 this will maintain the required alignment.
1326 If the stack grows downward, we could save an insn by subtracting
1327 SIZE from the stack pointer and then aligning the stack pointer.
1328 The problem with this is that the stack pointer may be unaligned
1329 between the execution of the subtraction and alignment insns and
1330 some machines do not allow this. Even on those that do, some
1331 signal handlers malfunction if a signal should occur between those
1332 insns. Since this is an extremely rare event, we have no reliable
1333 way of knowing which systems have this problem. So we avoid even
1334 momentarily mis-aligning the stack. */
1336 /* If we added a variable amount to SIZE,
1337 we can no longer assume it is aligned. */
1338 #if !defined (SETJMP_VIA_SAVE_AREA)
1339 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1341 size = round_push (size);
1343 do_pending_stack_adjust ();
1345 /* We ought to be called always on the toplevel and stack ought to be aligned
1347 if (stack_pointer_delta % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT))
1350 /* If needed, check that we have the required amount of stack. Take into
1351 account what has already been checked. */
1352 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1353 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1355 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1356 if (target == 0 || GET_CODE (target) != REG
1357 || REGNO (target) < FIRST_PSEUDO_REGISTER
1358 || GET_MODE (target) != Pmode)
1359 target = gen_reg_rtx (Pmode);
1361 mark_reg_pointer (target, known_align);
1363 /* Perform the required allocation from the stack. Some systems do
1364 this differently than simply incrementing/decrementing from the
1365 stack pointer, such as acquiring the space by calling malloc(). */
1366 #ifdef HAVE_allocate_stack
1367 if (HAVE_allocate_stack)
1369 enum machine_mode mode = STACK_SIZE_MODE;
1370 insn_operand_predicate_fn pred;
1372 /* We don't have to check against the predicate for operand 0 since
1373 TARGET is known to be a pseudo of the proper mode, which must
1374 be valid for the operand. For operand 1, convert to the
1375 proper mode and validate. */
1376 if (mode == VOIDmode)
1377 mode = insn_data[(int) CODE_FOR_allocate_stack].operand[1].mode;
1379 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1380 if (pred && ! ((*pred) (size, mode)))
1381 size = copy_to_mode_reg (mode, convert_to_mode (mode, size, 1));
1383 emit_insn (gen_allocate_stack (target, size));
1388 #ifndef STACK_GROWS_DOWNWARD
1389 emit_move_insn (target, virtual_stack_dynamic_rtx);
1392 /* Check stack bounds if necessary. */
1393 if (current_function_limit_stack)
1396 rtx space_available = gen_label_rtx ();
1397 #ifdef STACK_GROWS_DOWNWARD
1398 available = expand_binop (Pmode, sub_optab,
1399 stack_pointer_rtx, stack_limit_rtx,
1400 NULL_RTX, 1, OPTAB_WIDEN);
1402 available = expand_binop (Pmode, sub_optab,
1403 stack_limit_rtx, stack_pointer_rtx,
1404 NULL_RTX, 1, OPTAB_WIDEN);
1406 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1410 emit_insn (gen_trap ());
1413 error ("stack limits not supported on this target");
1415 emit_label (space_available);
1418 anti_adjust_stack (size);
1419 #ifdef SETJMP_VIA_SAVE_AREA
1420 if (setjmpless_size != NULL_RTX)
1422 rtx note_target = get_last_insn ();
1424 REG_NOTES (note_target)
1425 = gen_rtx_EXPR_LIST (REG_SAVE_AREA, setjmpless_size,
1426 REG_NOTES (note_target));
1428 #endif /* SETJMP_VIA_SAVE_AREA */
1430 #ifdef STACK_GROWS_DOWNWARD
1431 emit_move_insn (target, virtual_stack_dynamic_rtx);
1437 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1438 but we know it can't. So add ourselves and then do
1440 target = expand_binop (Pmode, add_optab, target,
1441 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1442 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1443 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1444 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1446 target = expand_mult (Pmode, target,
1447 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1451 /* Some systems require a particular insn to refer to the stack
1452 to make the pages exist. */
1455 emit_insn (gen_probe ());
1458 /* Record the new stack level for nonlocal gotos. */
1459 if (nonlocal_goto_handler_slots != 0)
1460 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
1465 /* A front end may want to override GCC's stack checking by providing a
1466 run-time routine to call to check the stack, so provide a mechanism for
1467 calling that routine. */
1469 static GTY(()) rtx stack_check_libfunc;
1472 set_stack_check_libfunc (libfunc)
1475 stack_check_libfunc = libfunc;
1478 /* Emit one stack probe at ADDRESS, an address within the stack. */
1481 emit_stack_probe (address)
1484 rtx memref = gen_rtx_MEM (word_mode, address);
1486 MEM_VOLATILE_P (memref) = 1;
1488 if (STACK_CHECK_PROBE_LOAD)
1489 emit_move_insn (gen_reg_rtx (word_mode), memref);
1491 emit_move_insn (memref, const0_rtx);
1494 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1495 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1496 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1497 subtract from the stack. If SIZE is constant, this is done
1498 with a fixed number of probes. Otherwise, we must make a loop. */
1500 #ifdef STACK_GROWS_DOWNWARD
1501 #define STACK_GROW_OP MINUS
1503 #define STACK_GROW_OP PLUS
1507 probe_stack_range (first, size)
1508 HOST_WIDE_INT first;
1511 /* First ensure SIZE is Pmode. */
1512 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1513 size = convert_to_mode (Pmode, size, 1);
1515 /* Next see if the front end has set up a function for us to call to
1517 if (stack_check_libfunc != 0)
1519 rtx addr = memory_address (QImode,
1520 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1522 plus_constant (size, first)));
1524 #ifdef POINTERS_EXTEND_UNSIGNED
1525 if (GET_MODE (addr) != ptr_mode)
1526 addr = convert_memory_address (ptr_mode, addr);
1529 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1533 /* Next see if we have an insn to check the stack. Use it if so. */
1534 #ifdef HAVE_check_stack
1535 else if (HAVE_check_stack)
1537 insn_operand_predicate_fn pred;
1539 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1541 plus_constant (size, first)),
1544 pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1545 if (pred && ! ((*pred) (last_addr, Pmode)))
1546 last_addr = copy_to_mode_reg (Pmode, last_addr);
1548 emit_insn (gen_check_stack (last_addr));
1552 /* If we have to generate explicit probes, see if we have a constant
1553 small number of them to generate. If so, that's the easy case. */
1554 else if (GET_CODE (size) == CONST_INT
1555 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1557 HOST_WIDE_INT offset;
1559 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1560 for values of N from 1 until it exceeds LAST. If only one
1561 probe is needed, this will not generate any code. Then probe
1563 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1564 offset < INTVAL (size);
1565 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1566 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1570 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1572 plus_constant (size, first)));
1575 /* In the variable case, do the same as above, but in a loop. We emit loop
1576 notes so that loop optimization can be done. */
1580 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1582 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1585 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1587 plus_constant (size, first)),
1589 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1590 rtx loop_lab = gen_label_rtx ();
1591 rtx test_lab = gen_label_rtx ();
1592 rtx end_lab = gen_label_rtx ();
1595 if (GET_CODE (test_addr) != REG
1596 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1597 test_addr = force_reg (Pmode, test_addr);
1599 emit_note (NULL, NOTE_INSN_LOOP_BEG);
1600 emit_jump (test_lab);
1602 emit_label (loop_lab);
1603 emit_stack_probe (test_addr);
1605 emit_note (NULL, NOTE_INSN_LOOP_CONT);
1607 #ifdef STACK_GROWS_DOWNWARD
1608 #define CMP_OPCODE GTU
1609 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1612 #define CMP_OPCODE LTU
1613 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1617 if (temp != test_addr)
1620 emit_label (test_lab);
1621 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1622 NULL_RTX, Pmode, 1, loop_lab);
1623 emit_jump (end_lab);
1624 emit_note (NULL, NOTE_INSN_LOOP_END);
1625 emit_label (end_lab);
1627 emit_stack_probe (last_addr);
1631 /* Return an rtx representing the register or memory location
1632 in which a scalar value of data type VALTYPE
1633 was returned by a function call to function FUNC.
1634 FUNC is a FUNCTION_DECL node if the precise function is known,
1636 OUTGOING is 1 if on a machine with register windows this function
1637 should return the register in which the function will put its result
1641 hard_function_value (valtype, func, outgoing)
1643 tree func ATTRIBUTE_UNUSED;
1644 int outgoing ATTRIBUTE_UNUSED;
1648 #ifdef FUNCTION_OUTGOING_VALUE
1650 val = FUNCTION_OUTGOING_VALUE (valtype, func);
1653 val = FUNCTION_VALUE (valtype, func);
1655 if (GET_CODE (val) == REG
1656 && GET_MODE (val) == BLKmode)
1658 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1659 enum machine_mode tmpmode;
1661 /* int_size_in_bytes can return -1. We don't need a check here
1662 since the value of bytes will be large enough that no mode
1663 will match and we will abort later in this function. */
1665 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1666 tmpmode != VOIDmode;
1667 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1669 /* Have we found a large enough mode? */
1670 if (GET_MODE_SIZE (tmpmode) >= bytes)
1674 /* No suitable mode found. */
1675 if (tmpmode == VOIDmode)
1678 PUT_MODE (val, tmpmode);
1683 /* Return an rtx representing the register or memory location
1684 in which a scalar value of mode MODE was returned by a library call. */
1687 hard_libcall_value (mode)
1688 enum machine_mode mode;
1690 return LIBCALL_VALUE (mode);
1693 /* Look up the tree code for a given rtx code
1694 to provide the arithmetic operation for REAL_ARITHMETIC.
1695 The function returns an int because the caller may not know
1696 what `enum tree_code' means. */
1699 rtx_to_tree_code (code)
1702 enum tree_code tcode;
1725 tcode = LAST_AND_UNUSED_TREE_CODE;
1728 return ((int) tcode);
1731 #include "gt-explow.h"